研究者データベース

木村 和弘(キムラ カズヒロ)
獣医学研究院 獣医学部門 基礎獣医科学分野
教授

基本情報

所属

  • 獣医学研究院 獣医学部門 基礎獣医科学分野

職名

  • 教授

学位

  • 博士(獣医学)

ホームページURL

研究キーワード

  • 肥満   Kupffer細胞   レプチン   プロスタグランジン   脱共役蛋白質   乳癌   グリコーゲン分解   脂肪細胞   ネコ   UCP   トロンボキサン   乳腺   マンナン   フエ-ス   サイクリックAMP   マンノース結合タンパク質   VEGF   ノックアウトマウス   脱共役タンパク質(uncoupling protein : UCP)   heregulin   プロラクチン   貪食   AMPキナーゼ   マンノース   Kapffer細胞   細胞呼吸   貧食   PAF   VEGF-B   乳房炎   エネルギー代謝   転写調節   細胞内情報伝達機構   Energy metabolism   Transcriptional control   Signal transdnction   

研究分野

  • ライフサイエンス / 獣医学
  • ライフサイエンス / 獣医学
  • ライフサイエンス / 獣医学
  • ライフサイエンス / 獣医学
  • ライフサイエンス / 獣医学
  • ライフサイエンス / 獣医学

職歴

  • 2007年06月 - 現在 北海道大学 (連合)獣医学研究科 教授
  • 1995年04月 - 2007年05月 北海道大学 (連合)獣医学研究科 助教授
  • 1989年10月 - 1995年03月 大阪府立大学(農学部) 助手
  • 1989年 - 1995年 Research Assistant, Osaka Prefecture
  • 1988年04月 - 1989年09月 大阪大学(医学部) 研究生
  • University

学歴

  • 1983年04月 - 1988年03月   北海道大学   大学院獣医学研究科
  •         - 1988年   北海道大学
  • 1979年04月 - 1983年03月   北海道大学   獣医学部
  •         - 1983年   北海道大学

所属学協会

  • 日本肥満学会   日本獣医学会   日本生化学会   

研究活動情報

論文

  • Tsubota A, Okamatsu-Ogura Y, Bariuan JV, Mae J, Matsuoka S, Nio-Kobayashi J, Kimura K
    The Journal of veterinary medical science 81 10 1461 - 1467 2019年10月 [査読有り][通常論文]
  • Izawa S, Chowdhury S, Miyazaki T, Mukai Y, Ono D, Inoue R, Ohmura Y, Mizoguchi H, Kimura K, Yoshioka M, Terao A, Kilduff TS, Yamanaka A
    Science (New York, N.Y.) 365 6459 1308 - 1313 2019年09月 [査読有り][通常論文]
  • Shin W, Okamatsu-Ogura Y, Matsuoka S, Tsubota A, Kimura K
    The Journal of veterinary medical science 81 6 799 - 807 2019年06月 [査読有り][通常論文]
  • Yoneshiro T, Shin W, Machida K, Fukano K, Tsubota A, Chen Y, Yasui H, Inanami O, Okamatsu-Ogura Y, Kimura K
    FASEB journal : official publication of the Federation of American Societies for Experimental Biology 33 4 5196 - 5207 2019年04月 [査読有り][通常論文]
     
    Bone marrow provides progenitors of several types of cells, including muscle and white adipocytes, ensuring peripheral tissue homeostasis. However, the role of bone marrow-derived cells (BMCs) in induction of thermogenic adipocytes is unresolved. The purpose of this study is to examine whether BMCs are involved in the emergence of thermogenic adipocytes through adrenergic activation. Irradiation of mice with 8 Gy of X-ray-depleted BMCs and peripheral blood mononucleated cells (PBMCs), which in turn impaired induction of uncoupling protein 1 (UCP1) through administration of β3 adrenergic receptor agonist, CL 316,243 (CL), in inguinal white adipose tissue (iWAT). In contrast, CL-induced UCP1 induction in brown adipose tissue was unaffected by BMC depletion. Transplantation of normal BMCs into mice depleted of BMCs recovered PBMC levels and rescued the ability of iWAT browning by CL. Furthermore, analyses of mice transplanted with green fluorescent protein (GFP)-labeled BMCs revealed that the number of GFP-positive BMCs and PBMCs were significantly decreased by CL and that GFP-positive stromal cells and GFP-positive UCP1-expressing multilocular adipocytes appeared in iWAT after CL administration, demonstrating differentiation of BMC-derived preadipocytes into UCP1-expressing thermogenic adipocytes. These results unveiled a crucial role of the BMC as a nonresident origin for a subset of thermogenic adipocytes, contributing to browning of white adipose tissue.-Yoneshiro, T., Shin, W., Machida, K., Fukano, K., Tsubota, A., Chen, Y., Yasui, H., Inanami, O., Okamatsu-Ogura, Y., Kimura, K. Differentiation of bone marrow-derived cells toward thermogenic adipocytes in white adipose tissue induced by the β3 adrenergic stimulation.
  • Okura Y, Imao T, Murashima S, Shibata H, Kamikavwa A, Okamatsu-Ogura Y, Saito M, Kimura K
    International journal of molecular sciences 20 7 2019年03月 [査読有り][通常論文]
  • Takeshi Yoneshiro, Ryuji Kaede, Kazuki Nagaya, Manami Saito, Julia Aoyama, Mohamed Elfeky, Yuko Okamatsu-Ogura, Kazuhiro Kimura, Akira Terao
    Nutrition research (New York, N.Y.) 58 17 - 25 2018年10月 [査読有り][通常論文]
     
    Dietary supplementation with melinjo (Gnetum gnemon L.) seed extract (MSE) has been proposed as an anti-obesity strategy. However, it remains unclear how MSE modulates energy balance. We tested the hypothesis that dietary MSE reduces energy intake and/or increases physical activity and metabolic thermogenesis in brown and white adipose tissue (BAT and WAT) in mice. Twenty-four C57BL/6 J mice were provided with normal diet, high-fat diet (HFD), or HFD with 1% MSE added, for 17 weeks. Food intake, spontaneous locomotor activity, hepatic triglyceride (TG) content, and blood parameters were examined. Mitochondrial thermogenesis-associated molecule and inflammatory marker expression levels in BAT and WAT were examined by quantitative PCR and western blotting. Dietary MSE did not affect energy intake or spontaneous locomotor activity, but significantly suppressed HFD-induced fat accumulation, hyperglycemia, and hyperinsulinemia. Homeostasis model assessment of insulin resistance score and hepatic TG content were both lower in the MSE-supplemented HFD-fed group than in the HFD-fed group, indicating reduced insulin resistance and a less fatty liver. Dietary MSE upregulated thermogenic uncoupling protein 1 (UCP1) and mitochondrial marker cytochrome c oxidase subunit IV protein expression in BAT; this was closely associated with sirtuin 1 mRNA induction. mRNAs of adipose inflammatory markers, such as monocyte chemotactic 1 and interleukin-1, were induced by HFD but suppressed by MSE. Considering that UCP1 protein expression is the most physiologically relevant parameter to assess the thermogenic capacities of BAT, our results indicate that dietary MSE supplementation induces BAT thermogenesis and reduces obesity-associated adipose tissue inflammation, hepatic steatosis, and insulin resistance.
  • Atsushi Watanabe, Eiji Hata, Petr Sláma, Kazuhiro Kimura, Tsunao Hirai
    Journal of Applied Animal Research 46 1 604 - 608 2018年08月25日 [査読有り][通常論文]
     
    To evaluate the relationship between intramammary infection and basic characteristics of mammary secretion at late dry period, regarding mammary secretions, macroscopic observations, infection status, somatic cell counts (SCC), serum albumin concentrations, immunoglobulin (Ig) G1and IgG2 levels were examined on 20 dairy cows at 9-12 days before calving. Intramammary infections were found in mammary secretions from 37 of the total 80 quarters. All of the mammary secretions with intramammary infection showed lower viscosity than that of normal colostrum. In four mammary secretions without intramammary infection, some macroscopic abnormalities were found. For mammary secretions without intramammary infection or macroscopic abnormality, viscosities were apparently higher than that in normal colostrum, indicating that viscosity is associated with macroscopic normality of the mammary secretion at approximately 10 days before calving. SCC and serum albumin concentrations were significantly higher in mammary secretions with intramammary infection or macroscopic abnormality. The SCC and serum albumin concentrations were correlated with viscosity of the mammary secretions, suggesting that most intramammary infections at approximately 10 days before calving may cause mastitis with increased permeability of the blood–milk barrier. No significant difference was observed in concentrations of IgG1 and IgG2regardless of the presence of intramammary infections or macroscopic abnormalities.
  • Kazuki Nagaya, Yuko Okamatsu-Ogura, Junko Nio-Kobayashi, Shohei Nakagiri, Ayumi Tsubota, Kazuhiro Kimura
    Journal of Physiological Sciences 1 - 8 2018年04月02日 [査読有り][通常論文]
     
    In Syrian hamsters, brown adipose tissue (BAT) develops postnatally through the proliferation and differentiation of brown adipocyte progenitors. In the study reported here, we investigated how ambient temperature influenced BAT formation in neonatal hamsters. In both hamsters raised at 23 or 30 °C, the interscapular fat changed from white to brown coloration in an age-dependent manner and acquired the typical morphological features of BAT by day 16. However, the expression of uncoupling protein 1, a brown adipocyte marker, and of vascular endothelial growth factor α were lower in the group raised at 30 °C than in that raised at 23 °C. Immunofluorescent staining revealed that the proportion of Ki67-expressing progenitors and endothelial cells was lower in the 30 °C group than in the 23 °C group. These results indicate that warm ambient temperature suppresses the proliferation of brown adipocyte progenitors and endothelial cells and negatively affects the postnatal development of BAT in Syrian hamsters.
  • Mohamed Elfeky, Takeshi Yoneshiro, Yuko Okamatsu-Ogura, Kazuhiro Kimura
    Journal of Biochemistry 163 2 143 - 153 2018年02月01日 [査読有り][通常論文]
     
    High-mobility group protein B1 (HMGB1) is a late inflammatory mediator released from inflammatory cells when stimulated, resulting in exaggerating septic symptoms. We recently demonstrated that full-length adiponectin, a potent anti-inflammatory adipokine, inhibits lipopolysaccharide-induced HMGB1 release. However, the effects of adiponectin on HMGB1-induced exaggerating signals currently remain unknown. This study aimed to investigate the effects of adiponectin on the pro-inflammatory function of HMGB1 in RAW264 macrophage cells. The treatment of RAW264 cells with HMGB1 significantly up-regulated the mRNA expression of tumour necrosis factor-α, interleukin-1β and C-X-C motif chemokine 10. HMGB1-induced cytokine expression was markedly suppressed by a toll-like receptor 4 (TLR4) antagonist and slightly suppressed by an antagonist of the receptor for advanced glycation end products. A prior treatment with full-length or globular adiponectin dose-dependently suppressed all types of HMGB1-induced cytokine expression, and this suppression was abolished by compound C, an AMPK inhibitor, but not by the haem oxygenase (HO)-1 inhibitor, zinc protoporphyrin IX. Both forms of adiponectin also reduced the mRNA expression of TLR4. These results suggest that full-length and globular adiponectin suppress HMGB1-induced cytokine expression through an AMPK-mediated HO-1-independent pathway.
  • Yuko Okamatsu-Ogura, Junko Nio-Kobayashi, Kazuki Nagaya, Ayumi Tsubota, Kazuhiro Kimura
    Journal of Applied Physiology 124 1 99 - 108 2018年01月01日 [査読有り][通常論文]
     
    To investigate the postnatal development of brown adipose tissue (BAT) in Syrian hamsters, we histologically examined interscapular fat tissue from 5-16-day-old pups, focusing on how brown adipocytes arise. Interscapular fat of 5-day-old hamsters mainly consisted of white adipocytes containing large unilocular lipid droplets, as observed in typical white adipose tissue (WAT). On day 7, clusters of small, proliferative nonadipocytes with a strong immunoreactivity for Ki67 appeared near the edge of the interscapular fat tissue. The area of the Ki67-positive regions expanded to ~50% of the total tissue area by day 10.The interscapular fat showed the typical BAT feature by day 16. A brown adipocyte-specific marker, uncoupling protein-1, was clearly detected on day 10 and thereafter, while not detected on day 7. During conversion of interscapular fat from WAT to BAT, unilocular adipocytes completely and rapidly disappeared without obvious apoptosis. Dual immunofluorescence staining for Ki67 and monocarboxylate transporter 1 (MCT1), another selective marker for brown adipocytes, revealed that most of the proliferating cells were of the brown adipocyte lineage. Electron microscopic examination showed that some of the white adipocytes contained small lipid droplets in addition to the large droplet and expressed MCT1 as do progenitor and mature brown adipocytes, implying a direct conversion from white to brown adipocytes. These results suggest that BAT of Syrian hamsters develops postnatally through two different pathways: The proliferation and differentiation of brown adipocyte progenitors and the conversion of unilocular adipocytes to multilocular brown adipocytes.
  • Takeshi Yoneshiro, Ryuji Kaede, Kazuki Nagaya, Julia Aoyama, Mana Saito, Yuko Okamatsu-Ogura, Kazuhiro Kimura, Akira Terao
    Obesity Research and Clinical Practice 12 1 127 - 137 2018年01月01日 [査読有り][通常論文]
     
    Introduction: Identification of thermogenic food ingredients is potentially a useful strategy for the prevention of obesity and related metabolic disorders. It has been reported that royal jelly (RJ) supplementation improves insulin sensitivity however, its impacts on energy expenditure and adiposity remain elusive. We investigated anti-obesity effects of RJ supplementation and their relation to physical activity levels and thermogenic capacities of brown (BAT) and white adipose tissue (WAT). Methods: C57BL/6J mice were fed under four different experimental conditions for 17 weeks: normal diet (ND), high fat diet (HFD), HFD with 5% RJ, and HFD with 5% honey bee larva powder (BL). Spontaneous locomotor activity, hepatic triglyceride (TG) content, and blood parameters were examined. Gene and protein expressions of thermogenic uncoupling protein 1 (UCP1) and mitochondrial cytochrome c oxidase subunit IV (COX-IV) in BAT and WAT were investigated by qPCR and Western blotting analysis, respectively. Results: Dietary RJ, but not BL, suppressed HFD-induced accumulations of WAT and hepatic TG without modifying food intake. Consistently, RJ improved hyperglycemia and the homeostasis model assessment-insulin resistance (HOMA-IR). Although dietary RJ and BL unchanged locomotor activity, gene and protein expressions of UCP1 and COX-IV in BAT were increased in the RJ group compared to the other experimental groups. Neither the RJ nor BL treatment induced browning of WAT. Conclusion: Our results indicate that dietary RJ ameliorates diet-induced obesity, hyperglycemia, and hepatic steatosis by promoting metabolic thermogenesis in BAT in mice. RJ may be a novel promising food ingredient to combat obesity and metabolic disorders.
  • Role of macrophages in depot-dependent browning of white adipose tissue.
    Machida, K, Okamatsu-Ogura, Y, Shin, W, Matsuoka, S, Tsubota, A, Kimura, K
    Journal of Physiological Sciences 68 601 - 608 2018年 [査読有り][通常論文]
  • D. Yamaji, M. M. Soliman, A. Kamikawa, T. Ito, M. M. Ahmed, Y. Okamatsu-Ogura, M. Saito, K. Kimura
    DOMESTIC ANIMAL ENDOCRINOLOGY 62 39 - 48 2018年01月 [査読有り][通常論文]
     
    Hepatocyte growth factor (HGF) is a mesenchymal cell-derived factor that regulates cell growth, cell motility, and morphogenesis. Since there are conflicting reports on HGF-producing cells, we herein examined HGF activity in conditioned medium (CM) of bovine and mouse preadipocytes before and after adipogenic differentiation. CM of bovine adipocytes and mouse preadipocytes induced the morphogenesis of mammary epithelial cells that was inhibited by an NK4 HGF antagonist, whereas CM of bovine preadipocytes and mouse adipocytes did not. HGF mRNA expression was increased by a treatment with dexamethasone and isobutylmethylxanthine in bovine as well as human cells, whereas it was decreased in rodent cells. It was unfortunate that HGF gene promoter activity failed to reflect HGF mRNA expression in these cells. After actinomycin D treatment, expression of HGF mRNA remained stable in pre- and differentiated bovine adipocytes and mouse preadipocytes, whereas rapidly decreased in mouse-differentiated adipocytes. These results indicate that expression and production of HGF are regulated in a species-specific adipogenic differentiation-dependent manner and suggest that the decrease in HGF mRNA in mouse differentiated adipocytes is, at least in part, mediated by differentiation-dependent loss of its stability. (C) 2017 Elsevier Inc. All rights reserved.
  • Yuko Okamatsu-Ogura, Keigo Fukano, Ayumi Tsubota, Junko Nio-Kobayashi, Kyoko Nakamura, Masami Morimatsu, Hiroshi Sakaue, Masayuki Saito, Kazuhiro Kimura
    SCIENTIFIC REPORTS 7 2017年07月 [査読有り][通常論文]
     
    We previously reported brown adipocytes can proliferate even after differentiation. To test the involvement of mature adipocyte proliferation in cell number control in fat tissue, we generated transgenic (Tg) mice over-expressing cell-cycle inhibitory protein p27 specifically in adipocytes, using the aP2 promoter. While there was no apparent difference in white adipose tissue (WAT) between wild-type (WT) and Tg mice, the amount of brown adipose tissue (BAT) was much smaller in Tg mice. Although BAT showed a normal cellular morphology, Tg mice had lower content of uncoupling protein 1 (UCP1) as a whole, and attenuated cold exposure-or beta 3-adrenergic receptor (AR) agonist-induced thermogenesis, with a decrease in the number of mature brown adipocytes expressing proliferation markers. An agonist for the beta 3-AR failed to increase the number of proliferating brown adipocytes, UCP1 content in BAT, and oxygen consumption in Tg mice, although the induction and the function of beige adipocytes in inguinal WAT from Tg mice were similar to WT mice. These results show that brown adipocyte proliferation significantly contributes to BAT development and adaptive thermogenesis in mice, but not to induction of beige adipocytes.
  • Mabrouk Attia Abd Eldaim, Shinya Matsuoka, Yuko Okamatsu-Ogura, Akihiro Kamikawa, Mohamed Mohamed Ahmed, Akira Terao, Kei-ichi Nakajima, Kazuhiro Kimura
    GENES TO CELLS 22 6 568 - 582 2017年06月 [査読有り][通常論文]
     
    It is well known that retinoic acid (RA) suppresses adipogenesis, although there are some contradicting reports. In this study, we examined the effect of extracellular glucose on RA-induced suppression of adipogenesis in 3T3L1 cell culture. When the cells were cultured in normal glucose medium (NG), the addition of RA suppressed lipid accumulation. However, when cultured in high glucose medium (HG), addition of RA to the cells enhanced lipid accumulation. These changes were accompanied by parallel alterations in fatty acid synthase (FAS) and sterol regulatory element-binding protein (SREBP)-1 gene expression. Transfection of SREBP-1 siRNA suppressed RA-induced enhancement of lipid accumulation and FAS expression in the cells cultured with HG. Transfection of the nuclear form of SREBP-1a cDNA into the cells cultured with NG inhibited RA-induced suppression of lipid accumulation and FAS expression. Moreover, RA- and HG-induced SREBP-1a expression occurred at the early phase of adipogenesis and was dependent on glucocorticoid to induce liver X receptor (LXR) , peroxisomal proliferator-activated receptor (PPAR) and retinoid X receptor (RXR), the key nuclear factors influencing the SREBP-1a gene expression. These results suggest that RA suppresses and enhances lipid accumulation through extracellular glucose concentration-dependent modulation of SREBP-1 expression.
  • Woongchul Shin, Yuko Okamatsu-Ogura, Ken Machida, Ayumi Tsubota, Junko Nio-Kobayashi, Kazuhiro Kimura
    OBESITY 25 2 417 - 423 2017年02月 [査読有り][通常論文]
     
    Objective: There are two types of thermogenic adipocytes expressing uncoupling protein ( UCP)-1: the brown adipocyte activated by adrenergic stimulation and the beige adipocyte that appears within the white adipose tissue ( WAT) in response to chronic adrenergic stimulation. This study examined age-related changes in responses of both types of adipocytes to adrenergic stimulation in mice. Methods: Aged ( age 20 months) and young ( 4 months) mice were injected daily with either saline or beta 3-adrenergic receptor agonist CL316,243 ( CL; 0.1 mg/kg, once a day) for 1 week. Results: The body and WAT weight tended to be higher in aged mice. CL treatment increased UCP-1 protein amounts in both brown adipose tissue and inguinal WAT, suggesting activation of brown and beige adipocytes. However, induction of beige adipocytes was impaired in aged mice, whereas brown adipocyte activation was comparable to young mice. The number of platelet-derived growth factor receptor alpha-expressing progenitor cells, which were reported to differentiate into beige adipocytes, significantly decreased in inguinal WAT of aged mice compared with that of young mice. Conclusions: Inductive ability of beige adipocytes in WAT declines with aging in mice. It may be partly because of a decreased number of progenitor cells associated with aging.
  • Tomoki Ito, Daisuke Yamaji, Akihiro Kamikawa, Mabrouk Attia Abd Eldaim, Yuko Okamatsu-Ogura, Akira Terao, Masayuki Saito, Kazuhiro Kimura
    ENDOCRINE JOURNAL 64 8 777 - 785 2017年 [査読有り][通常論文]
     
    It is well documented that estrogen is predominant inducer of hepatocyte growth factor (HGF) in a variety of cell types. However, the effect of progesterone (P) remains to be elusive. Thus, in the present study, we examined the effect of P and combined effect of P and 17 beta-estradiol (E2) on HGF expression and production in 3T3-L1 fibroblastic preadipocytes and mature adipocytes, as a model of stromal cells. Northern blot analysis showed that hgf mRNA expressed in preadipocytes was notably higher than that of mature adipocytes, and increased by treatment of preadipocytes with E2 or 10 nM P, but not with 1,000 nM P. The E2-induced hgf mRNA expression was enhanced by 10 nM P, but suppressed by 1,000 nM P. Western blot analysis revealed that biological active forms of HGF protein was found in the preadipocyte culture medium, while the lesser amount of HGF precursor protein was detected in the mature adipocyte culture medium. The amounts of HGF were changed dependently on the hgf mRNA expression levels. These results indicate that HGF production is intricately regulated by E2 and P at the transcriptional levels in 3T3-L1 cells, and may explain the changes in the HGF production during the mammary gland development, especially decrease in HGF expression during pregnancy when P concentration is high.
  • Keigo Fukano, Yuko Okamatsu-Ogura, Ayumi Tsubota, Junko Nio-Kobayashi, Kazuhiro Kimura
    PLOS ONE 11 11 2016年11月 [査読有り][通常論文]
     
    Hyperplasia of brown adipose tissue (BAT) is a fundamental mechanism for adaptation to survive in the cold environment in rodents. To determine which cell types comprising BAT contribute to tissue hyperplasia, immunohistochemical analysis using a proliferative marker Ki67 was performed on the BAT from 6-week-old C57BLJ6J mice housed at 23 degrees C (control) or 10 degrees C (cold) for 5 days. Interestingly, in the control group, the cell proliferative marker Ki67 was detected in the nuclei of uncoupling protein 1-positive mature brown adipocytes (7.2% +/- 0.4% of brown adipocyte), as well as in the non-adipocyte stromal-vascular (SV) cells (19.6% +/- 2.3% of SV cells), which include preadiopocytes. The percentage of Ki67-positive brown adipocytes increased to 25.6% +/- 1.8% at Day 1 after cold exposure and was significantly higher than the non-cold acclimated control until Day 5 (21.8%+/- 1.7%). On the other hand, the percentage of Ki67-positive SV cells gradually increased by a cold exposure and peaked to 42.1%+/- 8.3% at Day 5. Injection of a beta 3-adrenergic receptor (beta 3-AR) agonist for continuous 5 days increased the number of Ki67-positive brown adipocytes even at Day 1 but not that of SV cells. In addition, the beta 3-AR antagonist, but not beta 1-AR antagonist, attenuated the cold exposure-induced increase in the number of Ki67-positive brown adipocytes. These results suggest that mature brown adipocytes proliferate immediately after cold exposure in a beta 3-AR-mediated pathway. Thus, proliferation of mature brown adipocytes as well as preadipocytes in SV cells may contribute to cold exposure-induced BAT hyperplasia.
  • Mohamed Elfeky, Ryuji Kaede, Yuko Okamatsu-Ogura, Kazuhiro Kimura
    MEDIATORS OF INFLAMMATION 2016年 [査読有り][通常論文]
     
    High mobility group protein B1 (HMGB1) is a late inflammatory mediator that exaggerates septic symptoms. Adiponectin, an adipokine, has potent anti-inflammatory properties. However, possible effects of adiponectin on lipopolysaccharide-(LPS-) induced HMGB1 release are unknown. The aim of this study was to investigate effects of full length adiponectin on HMGB1 release in LPS-stimulated RAW 264 macrophage cells. Treatment of the cells with LPS alone significantly induced HMGB1 release associated with HMGB1 translocation from the nucleus to the cytosol. However, prior treatment with adiponectin suppressed LPS-induced HMGB1 release and translocation. The anti-inflammatory cytokine interleukin-(IL-) 10 similarly suppressed LPS-induced-HMGB1 release. Adiponectin treatment decreased toll-like receptor 4 (TLR4) mRNA expression and increased heme oxygenase-(HO-) 1 mRNA expression without inducing IL-10 mRNA, while IL-10 treatment decreased TLR2 and HMGB1 mRNA expression and increased the expression of IL-10 andHO-1mRNA. Treatment with the HO-1 inhibitor ZnPP completely prevented the suppression of HMGB1 release by adiponectin but only partially inhibited that induced by IL-10. Treatment with compound C, an AMP kinase (AMPK) inhibitor, abolished the increase in HO-1 expression and the suppression of HMGB1 release mediated by adiponectin. In conclusion, our results indicate that adiponectin suppresses HMGB1 release by LPS through an AMPK-mediated and HO-1-dependent IL-10-independent pathway.
  • Yuko Okamatsu-Ogura, Ayumi Tsubota, Kana Ohygma, Yoshihito Nogusa, Masayuki Saito, Kazuhiro Kimura
    JOURNAL OF FUNCTIONAL FOODS 19 1 - 9 2015年12月 [査読有り][通常論文]
     
    Capsinoids are less pungent capsaicin analogues that increase whole body energy expenditure and hence reduce fat. Several studies have suggested that capsinoids activate brown adipose tissue (BAT), a major site of adaptive thermogenesis, but the actual contribution of BAT and uncoupling protein 1 (UCP1), a thermogenic protein expressed in BAT, to the fat-reducing effect of capsinoids has not yet been determined. Here, we investigated the effect of capsinoids on high-fat diet (HFD)-induced obesity using wild-type (WT) and UCP1-deficient (KO) mice. Capsinoids feeding potently suppressed HFD-induced increase in body weight, adiposity, and fatty liver development in WT mice. In contrast, such effects of capsinoids were completely abolished in UCP1-KO mice. Moreover, capsinoids significantly increased UCP1 protein expression in BAT without its apparent induction in white adipose tissue (WAT) in WT mice. These results indicate that capsinoids suppress diet-induced obesity of mice through the UCP1 function in BAT but not in WAT. (C) 2015 Elsevier Ltd. All rights reserved.
  • Yuta Sakurai, Yuko Okamatsu-Ogura, Masayuki Saito, Kazuhiro Kimura, Ryo Nakao, Aiko Ohnuma, Mari Kobayashi
    MARINE MAMMAL SCIENCE 31 2 818 - 827 2015年04月 [査読有り][通常論文]
  • Yasufumi Teramura, Akira Terao, Yuko Okada, Junichi Tomida, Yuko Okamatsu-Ogura, Kazuhiro Kimura
    JAPANESE JOURNAL OF VETERINARY RESEARCH 62 3 117 - 127 2014年08月 [査読有り][通常論文]
     
    The effects of three stressors of different categories, namely cold exposure, immobilization, and lipopolysaccharide (LPS) treatment, on sympathetic nerve activity were examined by assessing its biochemical index norepinephrine (NE) turnover in peripheral organs of C57BL/6 mice. NE turnover was assessed by measuring the decrease in the organ NE concentration 3 h after inhibition of catecholamine biosynthesis with alpha-methyl-p-tyrosine. NE turnover in brown adipose tissue (BAT) in the room temperature (23 degrees C) control group was as high as that in the cold exposure (4 degrees C) group. Similarly, the mRNA level of the thermogenic marker uncoupling protein 1 (UCP1) in the room temperature control group was as high as that in the cold exposure group. As sympathetic stimulation upregulates the UCP1 mRNA level, we thought that sympathetic nerve tonus in BAT was already accelerated at room temperature. To exclude factors affecting basal sympathetic nerve activity, mice housed at thermoneutral temperature (30 degrees C) were used as controls for the subsequent experiments. In this condition, cold exposure accelerated NE turnover in the BAT, as well as heart and pancreas. The corticosterone level showed a higher trend in the cold exposure group in comparison to the control group. Immobilization accelerated NE turnover in the spleen, pancreas, and white adipose tissue and elevated the corticosterone level. LPS (3 mg/kg, i.p.) did not affect NE turnover in all peripheral organs but elevated the corticosterone level. In summary, the sympathetic nervous and adrenocortical responses to three stressors differed greatly. In particular, sympathetic responses showed clear organ-specific acceleration patterns. This important feature may improve our understanding of the multiplicity of biological responses.
  • Keigo Fukano, Kazuhiro Kimura
    CONCEPTUAL BACKGROUND AND BIOENERGETIC/MITOCHONDRIAL ASPECTS OF ONCOMETABOLISM 542 115 - 124 2014年 [査読有り][通常論文]
     
    Enolase (EC 4.2.1.11) is a cytosolic metalloenzyme responsible for the conversion of 2-phosphoglycerate into phosphoenolpyruvate, the second to last step in glycolysis. In mammals, enolase is encoded by three homologous genes. These gene products not only possess distinct biochemical and immunological properties but also show different tissue distribution. Besides its glycolytic function, alpha-enolase plays a variety of roles in pathophysiological settings including oncogenesis, tumor progression, ischemia, and bacterial infection. The expression levels of alpha-enolase have been attributed diagnostic and prognostic value in a number of tumors. Furthermore, neuron-specific alpha-enolase is released into the cerebrospinal fluid as well as in the systemic circulation upon traumatic brain injury and ischemic episodes. Thus, the measurement of the enzymatic activity of enolase is relevant for diverse fields of investigation, including oncometabolism. Here, we described simple and rapid protocols to measure the activity of enolase in lysates from mammalian cells and tissues.
  • Hiyoshi, H, Terao, A, Okamatsu-Ogura, Y, Kimura, K
    Experimental Animals 62 205 - 213 2014年 [査読有り][通常論文]
  • Yuko Okamatsu-Ogura, Keigo Fukano, Ayumi Tsubota, Akihiro Uozumi, Akira Terao, Kazuhiro Kimura, Masayuki Saito
    PLOS ONE 8 12 2013年12月 [査読有り][通常論文]
     
    Chronic adrenergic activation leads to the emergence of beige adipocytes in some depots of white adipose tissue in mice. Despite their morphological similarities to brown adipocytes and their expression of uncoupling protein 1 (UCP1), a thermogenic protein exclusively expressed in brown adipocytes, the beige adipocytes have a gene expression pattern distinct from that of brown adipocytes. However, it is unclear whether the thermogenic function of beige adipocytes is different from that of classical brown adipocytes existing in brown adipose tissue. To examine the thermogenic ability of UCP1 expressed in beige and brown adipocytes, the adipocytes were isolated from the fat depots of C57BL/6J mice housed at 24 degrees C (control group) or 10 degrees C (cold-acclimated group) for 3 weeks. Morphological and gene expression analyses revealed that the adipocytes isolated from brown adipose tissue of both the control and cold-acclimated groups consisted mainly of brown adipocytes. These brown adipocytes contained large amounts of UCP1 and increased their oxygen consumption when stimulated with norepinephirine. Adipocytes isolated from the perigonadal white adipose tissues of both groups and the inguinal white adipose tissue of the control group were white adipocytes that showed no increase in oxygen consumption after norepinephrine stimulation. Adipocytes isolated from the inguinal white adipose tissue of the cold-acclimated group were a mixture of white and beige adipocytes, which expressed UCP1 and increased their oxygen consumption in response to norepinephrine. The UCP1 content and thermogenic ability of beige adipocytes estimated on the basis of their abundance in the cell mixture were similar to those of brown adipocytes. These results revealed that the inducible beige adipocytes have potent thermogenic ability comparable to classical brown adipocytes.
  • Kyoko Tsukiyama-Kohara, Asao Katsume, Kazuhiro Kimura, Masayuki Saito, Michinori Kohara
    Genes to Cells 18 7 602 - 607 2013年07月 [査読有り][通常論文]
     
    4E Binding protein 1 (4E-BP1) suppresses translation initiation. The absence of 4E-BP1 drastically reduces the amount of adipose tissue in mice. To address the role of 4E-BP1 in adipocyte differentiation, we characterized 4E-BP1-/- mice in this study. The lack of 4E-BP1 decreased the amount of white adipose tissue and increased the amount of brown adipose tissue. In 4E-BP1-/- MEF cells, PPARγ coactivator 1 alpha (PGC-1α) expression increased and exogenous 4E-BP1 expression suppressed PGC-1α expression. The level of 4E-BP1 expression was higher in white adipocytes than in brown adipocytes and showed significantly greater up-regulation in white adipocytes than in brown adipocytes during preadipocyte differentiation into mature adipocytes. The amount of PGC-1α was consistently higher in HB cells (a brown preadipocyte cell line) than in HW cells (a white preadipocyte cell line) during differentiation. Moreover, the ectopic over-expression of 4E-BP1 suppressed PGC-1α expression in white adipocytes, but not in brown adipocytes. Thus, the results of our study indicate that 4E-BP1 may suppress brown adipocyte differentiation and PGC-1α expression in white adipose tissues. © 2013 by the Molecular Biology Society of Japan and Wiley Publishing Asia Pty Ltd.
  • Shogo Tanno, Akira Terao, Yuko Okamatsu-Ogura, Kazuhiro Kimura
    Obesity Research and Clinical Practice 7 4 e251 - e257 2013年07月 [査読有り][通常論文]
     
    Orexins are hypothalamic neuropeptides, which play important roles in the regulation and maintenance of sleep/wakefulness states and energy homeostasis. To evaluate whether alterations in orexin system is associated with the sleep/wakefulness abnormalities observed in obesity, we examined the mRNA expression of prepro-orexin, orexin receptor type 1 (orexin 1r), and orexin receptor type 2 (oxexin 2r) in the hypothalamus in mice fed with a normal diet (ND) and high-fat diet (HFD)-induced obese mice. We also compared their relationships with sleep/wakefulness. Twenty-four, 4-week-old, male C57BL/6J mice were divided randomly into three groups, which received the following: (1) ND for 17 weeks (2) HFD for 17 weeks and (3) ND for 7 weeks and HFD for a further 10 weeks. The body weights of mice fed the HFD for 10-17 weeks were 112-150% of the average body weight of the ND group. The daily amount of non-rapid eye movement (NREM) sleep increased significantly in HFD-fed mice. These changes were accompanied by increases in the number but decreases in the duration of each NREM sleep episode. In addition, brief awakenings (< 20 s epoch) during NREM sleep was nearly 2-fold more frequent. The mRNA level of prepro-orexin in the hypothalamus was significantly reduced in HFD-induced obese mice, whereas the levels of orexin 1r and orexin 2r were unaffected. The daily amount of NREM sleep was negatively correlated with the hypothalamic prepro-orexin mRNA level, so these results suggest that the increased NREM sleep levels in HFD-induced obese mice are attributable to impaired orexin activity. © 2013 Asian Oceanian Association for the Study of Obesity.
  • Effect of missense mutation of leptin gene on serum leptin concentration and some blood metabolic parameters in Czech pied bulls.
    Pavlik, A, Slama, P, Knoll, A, Dufek, A, Kimura, K, Subrt, J
    Bulgarian Journal of Agricultural Science 19 14425 - 1430 2013年 [査読有り][通常論文]
  • Ishii T, Fukano K, Shimada K, Kamikawa A, Okamatsu-Ogura Y, Terao A, Yoshida T, Saito M, Kimura K
    Journal of biochemistry 152 1 53 - 62 1 2012年07月 [査読有り][通常論文]
     
    Proinsulin C-peptide shows beneficial effects on microvascular complications of Type 1 diabetes. However, the possible occurrence of membrane C-peptide receptor(s) has not been elucidated. The aim of this study was to identify and characterize membrane proteins to which C-peptide binds. The enzyme alpha-enolase was co-immunoprecipitated with C-peptide after chemical cross-linking to HL-60 cell surface proteins and identified by mass spectrometry. Recombinant alpha-enolase activity was modulated by C-peptide, with a significant decrease in K-m for 2-phosphoglycerate without affecting V-max. The enzyme modulation by C-peptide was abolished when C-terminal basic lysine residue (K434) of the enzyme was replaced by neutral alanine or acidic glutamate, but not with basic arginine. The enzyme modulation by C-peptide was reproduced with the C-peptide fragments containing glutamate corresponding to position 27 (E27) of the full-length C-peptide. Addition of a lysine analogue to the assay and A31 cell culture abrogated the enzyme modulation and MAP kinase activation by C-peptide, respectively. The results indicate that C-peptide has the capacity to activate alpha-enolase through a specific interaction between E27 of the peptide and K434 of the enzyme. Since alpha-enolase plays a role as a cell surface receptor for plasminogen, it may conceivably also serve as a receptor for C-peptide in vivo.
  • Kohei Shimada, Yuta Ohno, Yuko Okamatsu-Ogura, Masahiro Suzuki, Akihiro Kamikawa, Akira Terao, Kazuhiro Kimura
    PEPTIDES 34 2 336 - 342 2012年04月 [査読有り][通常論文]
     
    The thermogenic function of brown adipose tissue (BAT) is increased by norepinephrine (NE) released from sympathetic nerve endings, but the roles of NPY released along with NE are poorly elucidated. Here, we examined effect of NPY on basal and NE-enhanced thermogenesis in isolated brown adipocytes that express Y1 and Y5 receptor mRNA. Treatment of cells with NPY did not influence the basal and NE-enhanced rates of oxygen consumption and cAMP accumulation. Treatment with NPY also failed to induce ERK (Thr202/Tyr204) phosphorylation in the brown adipocytes. In contrast, treatment with NPY increased ERK phosphorylation in cultured stromal vascular cells from the BAT that express Y1 receptor mRNA. In the latter treatment with NPY also increased STAT3 (Ser727) phosphorylation. These results suggest that NPY mainly acts on stromal vascular cells in BAT and plays roles in the regulation of their gene transcription through ERK and STAT3 pathways, while NPY does not affect the thermogenic function of brown adipocytes. (C) 2012 Elsevier Inc. All rights reserved.
  • Watanabe A, Hirota J, Shimizu S, Inumaru S, Kimura K
    Veterinary medicine international 2012 172072  2012年 [査読有り][通常論文]
  • Kazuhiro Kimura, Akihiro Kamikawa
    Diabetes & C-Peptide: Scientific and Clinical Aspects 55 - 65 2012年01月01日 [査読有り][通常論文]
  • Yuko Okamatsu-Ogura, Junko Nio-Kobayashi, Toshihiko Iwanaga, Akira Terao, Kazuhiro Kimura, Masayuki Saito
    EXPERIMENTAL BIOLOGY AND MEDICINE 236 11 1274 - 1281 2011年11月 [査読有り][通常論文]
     
    Leptin reduces body fat by decreasing food intake and increasing energy expenditure. Uncoupling protein (UCP) 1, a key molecule for brown adipose tissue (BAT) thermogenesis, was reported to contribute to the stimulatory effect of leptin on energy expenditure. To clarify whether UCP1 is also involved in the anorexigenic effect of leptin, in this study we examined the effect of leptin on food intake using wild-type (WT) and UCP1-deficient (UCP1-KO) mice. Repeated injection of leptin decreased food intake more markedly in WT mice than in UCP1-KO mice, while a single injection of leptin showed similar effects in the two groups of mice. As chronic leptin stimulation induces UCP1 expression in BAT and ectopically in white adipose tissue (WAT), we mimicked the UCP1 induction by repeated injection of CL316,243 (CL), a highly specific beta 3-adrenoceptor agonist, and measured food intake in response to a single injection of leptin. Two-week treatment with CL enhanced the anorexigenic effect of leptin in WT mice, but not in UCP1-KO mice. Three-day treatment with CL in WT mice also enhanced the anorexigenic effect of leptin and leptin-induced phosphorylation of signal transducer and activator of transcription 3 (STAT3) in the arcuate nucleus of the hypothalamus, without any notable change in adiposity. These results indicate that UCP1 enhances leptin action at the hypothalamus level, suggesting UCP1 contributes to the control of energy balance not only through the regulation of energy expenditure but also through appetite control by modulating leptin action.
  • Shigeki Shimba, Tomohiro Ogawa, Shunsuke Hitosugi, Yuya Ichihashi, Yuki Nakadaira, Munehiro Kobayashi, Masakatsu Tezuka, Yasuhiro Kosuge, Kumiko Ishige, Yoshihisa Ito, Kazuo Komiyama, Yuko Okamatsu-Ogura, Kazuhiro Kimura, Masayuki Saito
    PLOS ONE 6 9 e25231  2011年09月 [査読有り][通常論文]
     
    A link between circadian rhythm and metabolism has long been discussed. Circadian rhythm is controlled by positive and negative transcriptional and translational feedback loops composed of several clock genes. Among clock genes, the brain and muscle Arnt-like protein-1 (BMAL1) and circadian locomotor output cycles kaput (CLOCK) play important roles in the regulation of the positive rhythmic transcription. In addition to control of circadian rhythm, we have previously shown that BMAL1 regulates adipogenesis. In metabolic syndrome patients, the function of BMAL1 is dysregulated in visceral adipose tissue. In addition, analysis of SNPs has revealed that BMAL1 is associated with susceptibility to hypertension and type II diabetes. Furthermore, the significant roles of BMAL1 in pancreatic beta cells proliferation and maturation were recently reported. These results suggest that BMAL1 regulates energy homeostasis. Therefore, in this study, we examined whether loss of BMAL1 function is capable of inducing metabolic syndrome. Deficient of the Bmal1 gene in mice resulted in elevation of the respiratory quotient value, indicating that BMAL1 is involved in the utilization of fat as an energy source. Indeed, lack of Bmal1 reduced the capacity of fat storage in adipose tissue, resulting in an increase in the levels of circulating fatty acids, including triglycerides, free fatty acids, and cholesterol. Elevation of the circulating fatty acids level induced the formation of ectopic fat in the liver and skeletal muscle in Bmal1 -/- mice. Interestingly, ectopic fat formation was not observed in tissue-specific (liver or skeletal muscle) Bmal1 -/- mice even under high fat diet feeding condition. Therefore, we were led to conclude that BMAL1 is a crucial factor in the regulation of energy homeostasis, and disorders of the functions of BMAL1 lead to the development of metabolic syndrome.
  • Takashi Sawada, Hideaki Miyoshi, Kohei Shimada, Akira Suzuki, Yuko Okamatsu-Ogura, James W. Perfield, Takuma Kondo, So Nagai, Chikara Shimizu, Narihito Yoshioka, Andrew S. Greenberg, Kazuhiro Kimura, Takao Koike
    PLOS ONE 5 11 e14006  2010年11月 [査読有り][通常論文]
     
    Background: Perilipin A (PeriA) exclusively locates on adipocyte lipid droplets and is essential for lipid storage and lipolysis. Previously, we reported that adipocyte specific overexpression of PeriA caused resistance to diet-induced obesity and resulted in improved insulin sensitivity. In order to better understand the biological basis for this observed phenotype, we performed additional studies in this transgenic mouse model. Methodology and Principal Findings: When compared to control animals, whole body energy expenditure was increased in the transgenic mice. Subsequently, we performed DNA microarray analysis and real-time PCR on white adipose tissue. Consistent with the metabolic chamber data, we observed increased expression of genes associated with fatty acid beta-oxidation and heat production, and a decrease in the genes associated with lipid synthesis. Gene expression of Pgc1a, a regulator of fatty acid oxidation and Ucp1, a brown adipocyte specific protein, was increased in the white adipose tissue of the transgenic mice. This observation was subsequently verified by both Western blotting and histological examination. Expression of RIP140, a regulator of white adipocyte differentiation, and the lipid droplet protein FSP27 was decreased in the transgenic mice. Importantly, FSP27 has been shown to control gene expression of these crucial metabolic regulators. Overexpression of PeriA in 3T3-L1 adipocytes also reduced FSP27 expression and diminished lipid droplet size. Conclusions: These findings demonstrate that overexpression of PeriA in white adipocytes reduces lipid droplet size by decreasing FSP27 expression and thereby inducing a brown adipose tissue-like phenotype. Our data suggest that modulation of lipid droplet proteins in white adipocytes is a potential therapeutic strategy for the treatment of obesity and its related disorders.
  • Mabrouk A. Abd Eldaim, Yuko Okamatsu-Ogura, Akira Terao, Kazuhiro Kimura
    JAPANESE JOURNAL OF VETERINARY RESEARCH 58 3-4 149 - 154 2010年11月 [査読有り][通常論文]
     
    Both retinoic acid (RA) and oxidative stress (11202) increased transcription and cleavage of membrane-bound sterol regulatory element-binding protein (SREBP)-1, leading to enhanced transcription of fatty acid synthase (FAS) in hepatoma cells. On the other hand, RA and H2O2 decreased and increased lipogenesis in adipocytes, respectively, although roles of SREBP-1 activation in these effects remain to be elucidated. To elucidate its involvement, we examined the activation of SREBP-1a, expression of FAS genes and lipid accumulation in 3T3-L1 cells in the presence of RA and/or H2O2. RA (1 mu M) treatment suppressed expression of SREBP-la and FAS genes and lipid accumulation. H2O2 (2 mu M) treatment induced increased cleavage of SREBP-la, without affecting amounts of SREBP-1a mRNA and precursor protein, and enhanced expression of FAS gene and lipid accumulation. Increased cleavage of SREBP-1a by H2O2 was also observed even in the presence of RA. These results suggest that 11202 enhances a cleavage of SREBP-1a precursor protein, which independently occurs with the RA suppression of SREBP-1a gene expression, and that RA itself has no role in the SREBP-1a activation in adipocytes.
  • Lina Nordquist, Kohei Shimada, Tatsuya Ishii, Daniela Tomie Furuya, Akihiro Kamikawa, Kazuhiro Kimura
    DIABETES-METABOLISM RESEARCH AND REVIEWS 26 3 193 - 199 2010年03月 [査読有り][通常論文]
     
    Aims/Hypothesis C-peptide reduces renal damage in diabetic patients and experimental animal models. In vitro studies suggest that the renal effects of C-peptide may, in part, be explained by stimulation of Na+/K+-ATPase activity. However, the responses of Na+/K+-ATPase expression in the kidney of diabetic animals to C-peptide administration remain unclear. The aim of this study was to clarify the responses. Methods Type 1 diabetic rats were produced by injecting streptozotocin (STZ), and some of the rats were treated with either C-peptide or insulin by the aid of an osmotic pump for 1 week. The mRNA expression and immunohistochemical localization of Na+/K+-ATPase alpha 1-, alpha 2- and beta 3-subunits were investigated in the kidney of these rats. Results Na+/K+-ATPase alpha 1-subunit was abundantly expressed in the medullary collecting ducts of control animals, but the expression was markedly decreased in the diabetic state with concomitant decrease in its mRNA expression. Similar decreases were observed in the insulin-treated diabetic rats, whereas in the C-peptide-treated diabetic rats, there was no reduction in the alpha 1-expression. The beta 3-subunit was expressed in podocytes and parietal cells in the glomeruli, vascular endothelial cells, and cortical collecting ducts, but lesser signals were observed in the proximal and distal tubules. However, the beta 3-subunit did not appear to be affected by the diabetic state. Conclusions Diabetes selectively reduced Na+/K+-ATPase alpha 1-subunit expression and abundance. Chronic administration of C-peptide prevented this decrease. This implies a role for C-peptide in the long-term regulation of Na+/K+-ATPase function. Copyright (C) 2010 John Wiley & Sons, Ltd.
  • Mabrouk A. Abd Eldaim, Akihiro Kamikawa, Mohamed M. Soliman, Mohamed M. Ahmed, Yuko Okamatsu-Ogura, Akira Terao, Toru Miyamoto, Kazuhiro Kimura
    JOURNAL OF DAIRY RESEARCH 77 1 27 - 32 2010年02月 [査読有り][通常論文]
     
    Retinol-binding protein 4 (RBP4) is a plasma protein involved in retinol transportation, and recent evidence in rodents suggests that RBP4 is also a metabolic regulator that modifies insulin sensitivity. To assess how RBP4 levels are regulated in ruminants, we determined the RBP4 concentrations in bovine plasma and milk using Western blot analysis. Plasma RBP4 levels in non-pregnant non-lactating (control) cows were around 45 mu g/ml, which were sustained during 60-h fasting, but decreased significantly 4 h after lipopolysaccharide (LPS) administration. Basal plasma retinol concentration was around 30 mu g/dl, but this decreased to approximately one-third and one-half of these values during fasting and 8 h after LPS challenge, respectively. Plasma RBP4 and retinol levels in cows 3-6 d before parturition were comparable to those of the controls. However, on the day of parturition both were significantly decreased and had returned to basal levels by two weeks after calving. Interestingly, RBP4 was clearly detected in colostrum (16.4 +/- 5.6 mu g/ml) but was only faintly detected in milk from cows at 7 d and 15 d after calving. Retinol concentrations in colostrum were almost 10-fold higher than those in plasma, while those in milk were comparable to those in plasma. These results suggest that RBP4 and retinol levels are independently regulated under physiological and pathophysiological conditions and that RBP4, like retinol, is transferred from maternal stores to calves through colostrum.
  • Daniela Tomie Furuya, Tatsuya Ishii, Akihiro Kamikawa, Kohei Shimada, Ubiratan Fabres Machado, Masayuki Saito, Kazuhiro Kimura
    JAPANESE JOURNAL OF VETERINARY RESEARCH 57 3 163 - 167 2009年11月 [査読有り][通常論文]
     
    To characterize the roles of C-peptide in vascular homeostatic processes, we examined the genes regulated by C-peptide in LEII mouse lung microvascular endothelial cells. Treatment of the cells with C-peptide increased the expression of c-Jun N-terminal kinase 1 (JNK1) mRNA dose-dependently, accompanied by an increase in JNK1 protein content. Prior treatment of the cells with PD98059, an ERK kinase inhibitor or SB203580, a p38MAPK inhibitor, abrogated the C-peptide-elicited JNK1 mRNA expression. These results indicate that C-peptide increases JNK1 protein levels, possibly through ERK- and p38MAPK-dependent activation of JNK. gene transcription.
  • Mohamed Mohamed Soliman, Yakut Abdel-Fattah El-Senosi, Maysara Mahmoud Salem, Omniya Mahmoud Abdel Hamid, Kimura Kazuhiro
    JOURNAL OF VETERINARY SCIENCE 10 3 197 - 201 2009年09月 [査読有り][通常論文]
     
    Treatment of AIDS (HIV) and hepatitis C virus needs protease inhibitors (PI) to prevent viral replication. Uses of PI in therapy are usually associated with a decrease in body weight and dyslipidemia. Acylation stimulating protein (ASP) is a protein synthesized in adipocytes to increase triglycerides biosynthesis, for that the relation of PI and ASP to adipogenesis is tested in this work. ASP expression was increased during 3T3-L1 differentiation and reached a peak at day 8 with cell maturation. Addition of PI during adipocytes differentiation dose dependently and significantly (p < 0.5) inhibited the degree of triglycerides (TG) accumulation. Moreover, presence of ASP (450 ng/mL) in media significantly (p < 0.5) stimulated the degree of TG accumulation and there was additive stimulation for ASP when added with insulin (10 mu g/mL). Finally, when ASP in different doses (Low, 16.7; Medium, 45 and High, 450 ng/mL) incubated with a dose of x 150 PI, ASP partially inhibited the PI-inhibited adipogenesis and TG accumulation. The results in this study show that PI inhibit lipids accumulation and confirm role of ASP in TG biosynthesis and adipogenesis.
  • Akihiro Kamikawa, Osamu Ichii, Daisuke Yamaji, Takeshi Imao, Chihairu Suzuki, Yuko Okamatsu-Ogura, Akira Terao, Yasuhiro Kon, Kazuhiro Kimura
    DEVELOPMENTAL DYNAMICS 238 5 1092 - 1099 2009年05月 [査読有り][通常論文]
     
    Mammary glands develop postnatally in response to the hypothalamic-pituitary-gonadal axis. Obesity-induced changes in the local environment, however, retard mammary gland development during late pregnancy and lactation. To clarify the effects of obesity on fundamental duct development, we compared the mammary glands of nulliparous nonpregnant obese mice fed a high-fat diet with those of lean mice fed a normal diet. Obese mice had enlarged mammary glands, reflecting fat pad size, whereas the ducts in obese mice showed a less dense distribution with less frequent branching. Additionally, the ducts were surrounded by thick collagen layers, and were incompletely lined with myoepithelium. Because leptin receptors were localized in the epithelium region and leptin that was highly expressed in the obese glands suppressed mammary epithelial cell proliferation in vitro, the present results suggest that obesity disrupts mammary ductal development, possibly by remodeling the mammary microenvironment and promoting the expression of such paracrine factors as leptin. Developmental Dynamics 238:1092-1099, 2009. (C) 2009 Wiley-Liss, Inc.
  • Katsumi Ishioka, Asako Omachi, Noriyasu Sasaki, Kazuhiro Kimura, Masayuki Saito
    JOURNAL OF VETERINARY MEDICAL SCIENCE 71 2 189 - 194 2009年02月 [査読有り][通常論文]
     
    Adiponectin is an adipokine that is specifically expressed in adipose tissues, directly sensitizes the body to insulin via specific receptors and its decreased plasma concentration is responsible for insulin resistance in obese humans. Diabetes is all important problem also in veterinary medicine. and feline diabetes is very similar to human type 2 diabetes, in which obesity is an important risk factor. In the present Study. We obtained cDNA clones corresponding to feline adiponectin and adiponectin receptor 1 (AD-R1). whose nucleotide and deduced amino acid sequences were highly identical to those of other species, especially, the extra-cellular domain of feline AD-R1 was almost identical to that of human AD-R1. Adiponectin mRNA was exclusively detected in the adipose tissue. but AD-R1 was in all tissues tested in this study. Next. plasma samples were collected from 22 cats visiting veterinary practices. They were divided to 2 groups based on a five-point scale body condition score (BCS), Such as normal group (BCS ranged from 2.5 through 3.5) and obese group (BCS ranged from 4.0 through 5.0). Plasma adiponectin in obese cats (7.2 +/- 1.5 mu g/ml) was significantly lower than that of normal cats (18.0 +/- 3.2 mu g/ml). These results suggest that adiponectin may be responsible for insulin function also in the cat, and it can be a target molecule for treatment of obesity and diabetes in cats.
  • A. Omachi, Y. Matsushita, K. Kimura, M. Saito
    Research in Veterinary Science 85 2 214 - 219 2008年10月 [査読有り][通常論文]
     
    We have reported that chronic treatment with beta 3-adrenoceptor agonists reduces body fat content and induces the expression of mitochondrial thermogenic uncoupling protein 1 (UCP1) in adipose tissue in the dog. To evaluate the role of UCP1 in the anti-obesity effect of the agonists, we isolated adipocytes from subcutaneous fat pad of beagles before and after a 2-week treatment with AJ-9677, a specific beta 3-adrenoceptor agonist, and examined their thermogenic activity in vitro. Histological and protein analysis revealed that adipose tissues before the treatment were composed of unilocular cells filled with a single large droplet, while the tissues after the treatment contained many smaller and some multilocular adipocytes expressing UCP1 and abundant mitochondrial proteins. Before the treatment, oxygen consumption rate was very low and did not change even when the cells were stimulated by AJ-9677. Two-week AJ-9677 treatment increased basal oxygen consumption rate by 7-fold, and produced a clear responsiveness to AJ-9677 stimulation. Thus, chronic treatment with AJ-9677 induced UCP1 in adipocytes, where oxygen consumption increased in response to AJ-9677 stimulation. It was suggested that UCP1-dependent energy expenditure in adipose tissue contributes to the anti-obesity effect of beta 3-adrenoceptor agonist in dogs. (C) 2008 Elsevier Ltd. All rights reserved.
  • Naonobu Nishino, Yoshikazu Tamori, Sanshiro Tateya, Takayuki Kawaguchi, Tetsuro Shibakusa, Wataru Mizunoya, Kazuo Inoue, Riko Kitazawa, Sohei Kitazawa, Yasushi Matsuki, Ryuji Hiramatsu, Satoru Masubuchi, Asako Omachi, Kazuhiro Kimura, Masayuki Saito, Taku Amo, Shigeo Ohta, Tomohiro Yamaguchi, Takashi Osumi, Jinglei Cheng, Toyoshi Fujimoto, Harumi Nakao, Kazuki Nakao, Atsu Aiba, Hitoshi Okamura, Tohru Fushiki, Masato Kasuga
    JOURNAL OF CLINICAL INVESTIGATION 118 8 2808 - 2821 2008年08月 [査読有り][通常論文]
     
    White adipocytes are unique in that they contain large unilocular lipid droplets that occupy most of the cytoplasm. To identify genes involved in the maintenance of mature adipocytes, we expressed dominant-negative PPAR gamma in 3T3-L1 cells and performed a microarray screen. The fat-specific protein of 27 kDa (FSP27) was strongly downregulated in this context. FSP27 expression correlated with induction of differentiation in cultured preadipocytes, and the protein localized to lipid droplets in murine white adipocytes in vivo. Ablation of FSP27 in mice resulted in the formation of multilocular lipid droplets in these cells. Furthermore, FSP27-deficient mice were protected from diet-induced obesity and insulin resistance and displayed an increased metabolic rate due to increased mitochondrial biogenesis in white adipose tissue (WAT). Depletion of FSP27 by siRNA in murine cultured white adipocytes resulted in the formation of numerous small lipid droplets, increased lipolysis, and decreased triacylglycerol storage, while expression of FSP27 in COS cells promoted the formation of large lipid droplets. Our results suggest that FSP27 contributes to efficient energy storage in WAT by promoting the formation of unilocular lipid droplets, thereby restricting lipolysis. In addition, we found that the nature of lipid accumulation in WAT appears to be associated with maintenance of energy balance and insulin sensitivity.
  • Mohamed Ahmed, Kazuhiro Kimura, Mohamed Soliman, Daisuke Yamaji, Yuko Okamatsu-Ogura, Katsumi Ishioka, Kennedy Makondo, Katsuro Hagiwara, Masayuki Saito
    Veterinary journal (London, England : 1997) 176 3 361 - 8 2008年06月 [査読有り][通常論文]
     
    This study examined the mitogenic response of bovine peripheral T lymphocytes to leptin, a pleiotropic hormone regulating food intake and energy expenditure. Leptin alone slightly suppressed proliferation of T lymphocytes in the presence of concanavalin A (ConA). Leptin also inhibited proliferation of T lymphocytes induced by anti-CD3 antibody. ConA treatment activated some protein kinases, including p44/p42(MAPK) and Akt/PKB, while anti-CD3 antibody treatment increased mRNA expression of suppressor of cytokine signalling (SOCS) 3, interferon (IFN)gamma, interleukin (IL) 2 and IL4 in T lymphocytes. Leptin alone increased only SOCS3 mRNA expression. Simultaneous treatment with mitogens and leptin enhanced IFNgamma mRNA expression but decreased IL2 mRNA expression, without any synergistic effect on phosphorylation of protein kinases or mRNA expression of SOCS3 and IL4. These results suggest that leptin modulates bovine T lymphocyte functions.
  • Akihiro Kamikawa, Tatsuya Ishii, Kohei Shimada, Kennedy Makondo, Osamu Inanami, Naoki Sakane, Toshihide Yoshida, Masayuki Saito, Kazuhiro Kimura
    DIABETES-METABOLISM RESEARCH AND REVIEWS 24 4 331 - 338 2008年05月 [査読有り][通常論文]
     
    Background Proinsulin C-peptide shows ameliorative effects on diabetic complications, possibly through the production of nitric oxide (NO). On the contrary, increased local availability of NO and expression of endothelial NO synthase (eNOS) in the renal endothelium are shown to be involved in the progression of diabetic nephropathy. The aim of this study was to elucidate the effect of C-peptide and insulin as a reference on the eNOS expression in the early phase of type 1 diabetic rat kidney. Methods Type 1 diabetes in rats was produced by streptozotocin injection and some of the rats were treated with either C-peptide or insulin by the aid of an osmotic pump for 1 week. Conventional biochemical and histological analyses were performed on tissue samples. Results The diabetic rats showed hyperglycemia with over 90% reduction of endogenous insulin and C-peptide. Replacement with C-peptide or insulin resulted in recovery of weight lost, but only insulin infusion lowered plasma-glucose concentration. The eNOS protein was localized in glomeruli and endothelial cells of arterioles, and its amounts in the kidneys, but not in the lungs, of diabetic rats was increased. Replacement with C-peptide or insulin-abrogated diabetes-induced increase of renal eNOS protein. Conclusion The results indicate that C-peptide suppresses diabetes-induced abnormal renal eNOS expression, by which C-peptide may exert beneficial effects on diabetic nephropathy. Copyright (C) 2007 John Wiley & Sons, Ltd.
  • 大町麻子, 石岡克己, 寺尾晶, 木村和弘
    ペット栄養学会誌 11 1 13 - 19 2008年04月 [査読有り][通常論文]
  • Kennedy Makondo, Akihiro Kamikawa, Mohamed Ahmed, Akira Terao, Masayuki Saito, Kazuhiro Kimura
    EUROPEAN JOURNAL OF PHARMACOLOGY 582 1-3 110 - 115 2008年03月 [査読有り][通常論文]
     
    Previously, we demonstrated that hepatocyte growth factor (HGF) potently stimulates endothelial nitric oxide synthase (eNOS) activity and nitric oxide (NO) production through a calcium- and Akt-mediated phosphorylation at Ser-1179 (Ser-1177 human) in bovine aortic endothelial cells. The regulation of eNOS, however, also involves interaction with chaperone proteins such as heat shock protein (HSP) 90, which can be enhanced by agonist stimulation of the enzyme. In the present work, the role of HSP90 in HGF stimulation of eNOS was examined in an endothelial cell culture system. Treatment of endothelial cells with geldanamycin, a commonly used HSP90 inhibitor, augmented HGF-stimulated eNOS phosphorylation at Ser-1179, while it did not alter eNOS phosphorylation at Thr-497. However, other HSP90 inhibitors, namely 17-(allylamino)-17-demethoxygeldanamycin (17-AAG) and radicicol, did not possess similar effects. Neither HGF nor geldanamycin treatment, independently or in combination, altered HSP90/eNOS interaction in endothelial cells. In addition, geldanamycin treatment did not enhance the HGF-induced phosphorylation of Akt, ERK1/2 and p38MAPK. Src kinase inhibition by PP2 also failed to block the geldanamycin effects. These results suggest that geldanamycin, but neither 17-AAG nor radicicol, may enhance HGF-mediated eNOS Ser-1179 phosphorylation. by some as yet unknown mechanisms independently of HSP90 inhibition. (c) 2007 Elsevier B.V. All rights reserved.
  • Akira Terao, Takashi Haruyama, Kazuhiro Kimura
    JAPANESE JOURNAL OF VETERINARY RESEARCH 55 2-3 75 - 83 2008年01月 [査読有り][通常論文]
     
    Hypocretin/orexin is produced exclusively in the dorsal and lateral hypothalamus but its projection is widespread within the brain and plays important roles. In this paper, we review the independent discoveries of the hypocretin/orexin peptides, the neuroanatomy of this system, and the link to the sleep disorder narcolepsy that has led to the idea that this system plays a crucial role in the regulation of sleep and wakefulness.
  • Yuko Okamatsu-Ogura, Akihiro Uozumi, Chitoku Toda, Kazuhiro Kimura, Hitoshi Yamashita, Masayuki Saito
    OBESITY RESEARCH & CLINICAL PRACTICE 1 4 233 - 241 2007年12月 [査読有り][通常論文]
     
    Leptin is proposed to reduce body fat by increasing energy expenditure, in addition to decreasing food intake, through the activation of brown adipose tissue (BAT) thermogenesis. To confirm this, we investigated the effects of leptin on whole body energy expenditure, BAT functions and adiposity in wild-type (WT) mice, and compared with those in mice deficient in uncoupling protein 1 (UCP1), a key molecule for BAT thermogenesis. Chronic hyperleptinemia induced by adenovirus gene transfer reduced food intake in both WT and UCP1-KO mice. WT mice with hyperleptinemia, compared to pair-fed controls, showed increased oxygen consumption, elevated UCP1 expression in BAT, ectopic UCP1 induction in white adipose tissue (WAT), and reduced body fat content. These effects of chronic hyperleptinemia were not observed in UCP1-KO mice. It was concluded that the fat-reducing effect of leptin is due to not only decreased food intake, but also increased UCP1-dependent energy expenditure. (c) 2007 Asian Oceanian Association for the Study of Obesity. Published by Elsevier Ltd. All rights reserved.
  • Mohamed Soliman, Kazuhiro Kimura, Mohamed Ahmed, Daisuke Yamaji, Yukiko Matsushita, Yuko Okamatsu-Ogura, Kennedy Makondo, Masayuki Saito
    DOMESTIC ANIMAL ENDOCRINOLOGY 33 4 400 - 409 2007年11月 [査読有り][通常論文]
     
    Leptin is an adipose tissue-derived cytokine plays key roles in the regulation of food intake and energy expenditure. However, regulatory mechanisms of leptin gene expression are not fully elucidated in ruminants that utilize short-chain fatty acids (SCFA), known as volatile fatty acids, as principal energy sources. In this study, we determined effects of SCFA and long-chain fatty acids (LCFA) on leptin expression in bovine adipocytes. Bovine stromal vascular cells isolated from subcutaneous adipose tissue of Holstein cows were cultured to confluence and treated sequentially with dexamethasone and isobutylmethylxanthine for 2 days and insulin and troglitazone for 12 days to achieve full differentiation to adipocytes. The cells started to accumulate lipids 4 days after the onset of treatment, with increased mRNA expression of leptin, as well as aP2, adiponectin, and PPAR-gamma. Removal of fetal calf serum and reduction of glucose in the culture medium of differentiated adipocytes decreased leptin mRNA expression. Subsequent addition of acetate, butyrate, or propionate dose-dependently restored and rather increased leptin expression, while addition of LCFA suppressed it. The stimulatory effect of acetate was abolished by prior treatment of the cells with pertussis toxin and by addition of LCFA. Furthermore, cows fasted for 48 h and fed thereafter, elaborate reduced and increased plasma leptin levels, respectively. Thus. these results suggest that plasma leptin levels in cows are inversely controlled at the transcription level by VFA and LCFA, and that the effects of SCFA possibly act through a G protein-coupled receptor for SCFA. (c) 2006 Elsevier Inc. All rights reserved.
  • Naoya Kitao, Takahiro Yahata, Takaaki Matsumoto, Yuko Okamatsu-Ogura, Asako Omachi, Kazuhiro Kimura, Masayuki Saito
    The Journal of veterinary medical science 69 10 1065 - 8 2007年10月 [査読有り][通常論文]
     
    Uncoupling protein 1 (UCP1) is present exclusively in brown adipose tissue, and contributes to body temperature control during cold exposure. We cloned UCP1 cDNA of plateau pika (Ochotona dauurica), a small, non-hibernating, diurnal lagomorph that inhabits in relatively cold climates and at high altitudes in Mongolia and in northern China. The nucleotide sequence of pika UCP1 was highly homologous to UCP1 of other species, and the deduced amino acid sequence had some common domains for UCP, including six mitochondrial carrier protein motifs and a putative purine-nucleotide binding site. RT-PCR and Western blot analyses revealed that both UCP1 mRNA and protein were expressed exclusively in the interscapular adipose tissue. These results suggest that pika UCP1 contributes to heat production in brown adipose tissue, as do those in other species.
  • Wakako Fujimoto, Tetsuya Shiuchi, Takashi Miki, Yasuhiko Minokoshi, Yoshihisa Takahashi, Ayako Takeuchi, Kazuhiro Kimura, Masayuki Saito, Toshihiko Iwanaga, Susumu Seino
    PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA 104 39 15514 - 15519 2007年09月 [査読有り][通常論文]
     
    Dmbx1 is a paired-class homeodomain transcription factor. We show here that mice deficient in Dmbx1 exhibit severe leanness associated with hypophagia and hyperactivity and that isolation of a Dmbx1(-/-) mouse from its cohabitants induces self-starvation, sometimes leading to death, features similar to those of anorexia nervosa in humans. Interestingly, overexpression of agouti in Dmbx1(-/-) mice failed to induce aspects of the A(y/a) phenotype, including hyperphagia, obesity, and diabetes mellitus. In Dmbx1(-/-) mice, administration of agouti-related protein increased cumulative food intake for the initial 6 h but significantly decreased it over 24- and 48-h periods. In addition, Dmbx1 was shown to be expressed at embryonic day 15.5 in the lateral parabrachial nucleus, the rostral nucleus of the tractus solitarius, the dorsal motor nucleus of the vagus, and the reticular nucleus in the brainstem, all of which receive melanocortin signaling, indicating involvement of Dmbx1 in the development of the neural network for the signaling. Thus, Dmbx1 is essential for various actions of agouti-related protein and plays a role in normal regulation of energy homeostasis and behavior.
  • A. Omachi, K. Ishioka, A. Uozumi, A. Kamikawa, C. Toda, K. Kimura, M. Saito
    Research in Veterinary Science 83 1 5 - 11 2007年08月 [査読有り][通常論文]
     
    A selective beta 3-adrenoceptor agonist, AJ-9677, was reported to ameliorate obesity and insulin resistance in KK-Ay mice. We examined the acute and chronic effects of AJ-9677 on obese dogs. Oral administration of AJ-9677 (0.01 or 0.1 mg/kg) to overnight fasted obese beagles produced a dose-dependent rise in the plasma levels of non-esterified fatty acids and insulin in I h, followed by a gradual drop of the plasma glucose level. It produced no apparent abnormal behaviors, but easily detectable cutaneous flushing. Daily treatment of AJ-9677 at a lower dose (0.01 mg/kg) for three weeks produced no notable change in body weight, but at a higher dose (0.1 mg/kg) it reduced the body weight compared to a placebo treatment after seven weeks. Computed tomographic examinations revealed a remarkable reduction of body fat after the AJ treatment, being consistent with the histological observations that the adipose tissue of AJ-9677-treated dogs consisted of smaller and some multilocular adipocytes. The plasma levels of leptin and adiponectin were decreased and increased, respectively, after the AJ treatment, reflecting the reduction of adiposity. It was concluded that AJ-9677 is useful for the treatment of obesity in the dog. (c) 2006 Elsevier Ltd. All rights reserved.
  • Yuko Okamatsu-Ogura, Naoya Kitao, Kazuhiro Kimura, Masayuki Saito
    INTERNATIONAL JOURNAL OF OBESITY 31 S58 - S58 2007年05月 [査読有り][通常論文]
  • Mohamed Ahmed, Zein Shaban, Daisuke Yamaji, Yuko Okamatsu-Ogura, Mohamed Soliman, Mabrouk Abd Eldaim, Katsumi Ishioka, Kennedy Makondo, Masayuki Saito, Kazuhiro Kimura
    JOURNAL OF VETERINARY MEDICAL SCIENCE 69 5 509 - 514 2007年05月 [査読有り][通常論文]
     
    The proliferation of peripheral blood mononuclear cells (PBMC) containing both monocyte/macrophages and T lymphocytes increased after treatment with T-cell mitogen (concanavalin A: Con A). PBMC treated with either leptin alone or combination of leptin and ConA showed enhanced proliferative activity by 10-40%, compared with those treated with ConA alone. In contrast, isolated T lymphocytes treated with leptin and ConA showed lowered proliferative activity than the ConA-treated alone, indicating that leptin induced production of some cytokines from monocyte/macrophages, that subsequently resulted in enhancement of T lymphocytes proliferation in PBMC. Among the cytokines examined, monocyte/monocytes constitutively expressed interleukin (IL)-1 beta, IL-12p35, IL-18 mRNA, and faintly expressed tumor necrosis factor (TNF)-alpha and IL-12p40 mRNA. Leptin treatment augmented the monocyte/macrophages mRNA expression of only TNF-alpha and IL-12p40 to comparable levels of cells treated with lipopolysaccharide (LPS). However, leptin treatment increased monocyte/macrophages production of IL-1 beta as well as TNF-alpha, and induced the mRNA expression of caspase-1, which is shown to mediate the conversion of latent pro-IL-1 beta and pro-IL-18 to active forms. These results suggest that leptin directly acts on monocyte/macrophages to produce factors that induce T lymphocytes proliferation such as IL-12p35/p40 complex through IL12p40 induction and IL-1 beta/IL-18 production through caspase-1 induction.
  • Yuko Okamatsu-Ogura, Naoya Kitao, Kazuhiro Kimura, Masayuki Saito
    AMERICAN JOURNAL OF PHYSIOLOGY-ENDOCRINOLOGY AND METABOLISM 292 4 E1135 - E1139 2007年04月 [査読有り][通常論文]
     
    Brown fat UCP1 is not involved in the febrile and thermogenic responses to IL-1 beta in mice. Am J Physiol Endocrinol Metab 292: E1135-E1139, 2007. First published December 12, 2006; doi:10.1152/ajpendo.00425.2006. - The activity of brown adipose tissue (BAT), a site of nonshivering metabolic thermogenesis, has been reported to increase after interleukin (IL)-1 beta/lipopolysaccharide injection. To clarify the possible contribution of BAT thermogenesis to whole body febrile response, we investigated febrile and thermogenic response to IL-1 beta using mice deficient in uncoupling protein-1 (UCP1), a key molecule for BAT thermogenesis. In wild-type (WT) mice, IL-1 beta injection (5 mu g/kg ip) increased body temperature (+1.82 degrees C at 20 min), decreased physical activity (-37% at 1 h), and produced a slight and insignificant rise (+15% at 1 h) in oxygen consumption (V-O2). V-O2 dependent on metabolic thermogenesis (Delta V-O2 thermogenesis) calculated by correcting the effect of physical activity was increased after IL-1 beta injection (726 +/- 200 ml center dot h(-1)center dot kg(-1) at 1 h). Almost the same responses were observed in UCP1-deficient mice, showing 638 +/- 87 ml center dot h(-1)center dot kg(-1) of Delta V-O2 (thermogenesis) at 1 h. In contrast, CL316,243, a selective activator of BAT thermogenesis, increased body temperature, decreased physical activity, and produced a significant rise in V-O2 in WT mice, showing 1,229 +/- 35 ml center dot h(-1)center dot kg(-1) of Delta V-O2 thermogenesis at 1 h. These changes were not observed in UCP1-deficient mice. These results, conflicting with a previously proposed idea of a role of BAT in fever, suggest a minor contribution of BAT thermogenesis to IL-1 beta-induced fever. In support of this, we found no effect of IL-1 beta on triglyceride content and UCP1 mRNA level in BAT, in contrast with apparent effects of CL316,243.
  • Mohamed Ahmed, Kazuhiro Kimura, Mohamed Soliman, Daisuke Yamaji, Yuko Okamatsu-Ogura, Kennedy Makondo, Osamu Inanami, Masayuki Saito
    JOURNAL OF VETERINARY MEDICAL SCIENCE 69 2 125 - 131 2007年02月 [査読有り][通常論文]
     
    Leptin, a pleiotropic hormone regulating food intake and energy expenditure, has been shown to directly modulate human polymorphonuclear neutrophil (PMN) functions or indirectly through the action of tumor necrosis factor-alpha (TNF-alpha). Bovine PMN have considerable different characteristics from human PMN. For example, it does not respond to N-formyl-Methionyl-Leucyl-phenylalanine, a well known human PMN activator. In the present study, we tested the effects of leptin and TNF-alpha on superoxide production and degranulation of bovine peripheral PMN, in which both long isoform of leptin receptor (Ob-Rb) and TNF receptor I were expressed. Human leptin, human TNF-a, phorbol myristate acetate (PMA) and opsonized zymosan particles (OZP) did not stimulate degranulation responses, while zymosan-activated serum (ZAS) did. Neither leptin nor TNF-alpha enhanced the ZAS-induced degranulation responses. TNF-alpha, PMA, OZP and ZAS increased superoxide production in different magnitudes, whereas leptin did not. TNF-alpha, but not leptin, enhanced OZP- and ZAS-induced superoxide production, possibly, in part due to facilitating translocation of p47(phox), a component of NADPH oxidase. These results indicate that, unlike in human PMN, leptin does not have any direct effect on degranulation and superoxide production in bovine PMN, although TNF-alpha. influences superoxide production.
  • Daisuke Yamaji, Akihiro Kamikawa, Mohamed M. Soliman, Tomoki Ito, Mohamed M. Ahmed, Kennedy Makondo, Atsushi Watanabe, Masayuki Saito, Kazuhiro Kimura
    JAPANESE JOURNAL OF VETERINARY RESEARCH 54 4 183 - 189 2007年02月 [査読有り][通常論文]
     
    We examined the effect of stroma-derived factors, hepatocyte growth factor (HGF) and leptin, on morphological differentiation of bovine mammary epithelial cells (BMEC) in collagen gel three-dimensional culture in vitro. BMEC treated with HGF, but not leptin, formed duct-like organoids. The formation of organoids by HGF was enhanced by treatment with a mixture of insulin, cortisol and prolactin, while BMEC treated with the mixture alone did not produce the organoid. In contrast, the formation of organoids by HGF was dose-dependently inhibited by simultaneous addition of leptin, regardless of the presence or absence of the hormone mixture. These results suggest that stroma-derived factors intricately regulate mammary epithelial morphogenesis.
  • K. Ishioka, K. Hosoya, H. Kitagawa, H. Shibata, T. Honjoh, K. Kimura, M. Saito
    RESEARCH IN VETERINARY SCIENCE 82 1 11 - 15 2007年02月 [査読有り][通常論文]
     
    Leptin is a cytokine produced by adipocytes, and plays a key role in the regulation of energy balance. In the present study, we measured plasma leptin concentrations of 166 normal and obese dogs visiting veterinary practices, and clarified the influence of age, gender and breed on plasma leptin levels in dogs. Leptin levels were higher in the dogs with higher body condition scores. There was no noticeable influence of age, gender and breed, but those in optimal puppies and obese Miniature Dachshund tended to be lower than those in corresponding groups. We conclude that plasma leptin is a reliable marker of adiposity in dogs regardless of age, gender and breed variations, and thereby useful as a blood biochemistry test for health examinations and treatment of obesity. (c) 2006 Elsevier Ltd. All rights reserved.
  • Yuko Okamatsu-Ogura, Akihiro Uozumi, Naoya Kitao, Kazuhiro Kimura, Masayuki Saito
    OBESITY RESEARCH & CLINICAL PRACTICE 1 1 61 - 67 2007年01月 [査読有り][通常論文]
     
    beta 3-adrenergic receptor (beta 3-AR) agonist, a drug that reduces body fat, stimulates lipomobilization from white adipose tissue (WAT) and thermogenesis in brown adipose tissue (BAT). To test the day-night difference in the effects of beta 3-AR agonist, in the present study, we examined the responses of lipomobitization and energy expenditure to CL316,243 (CL) during the daytime at 10:00 and nighttime at 22:00 in mice kept in a 12 h light-dark cycle with lights on from 07:00. CL injection increased plasma free fatty acid to the same extent at 10:00 and 22:00. In contrast, CL injection increased total oxygen consumption more markedly at 10:00 than 22:00. Physical activity was suppressed by CL injection especially at 22:00. Correcting total oxygen consumption by the suppressive effect on physical activity, oxygen consumption dependent on BAT thermogenesis was estimated. This revealed that the effect of CL on BAT thermogenesis was not different between 10:00 and 22:00. Thus, we concluded that there is no day-night difference in the CL effects on lipomobilization from WAT and thermogenesis in BAT. The stronger effect of CL on total energy expenditure in the daytime was largely due to a more suppressive effect on physical activity in the nighttime. (C) 2006 Asian Oceanian Association for the Study of Obesity. Published by Elsevier Ltd. All rights reserved.
  • YX Wang, K Kimura, K Inokuma, M Saito, Y Kontani, Y Kobayashi, N Mori, H Yamashita
    PFLUGERS ARCHIV-EUROPEAN JOURNAL OF PHYSIOLOGY 452 3 363 - 369 2006年06月 [査読有り][通常論文]
     
    To investigate the thermoregulatory mechanism in mice lacking uncoupling protein 1 (UCP1) from the viewpoint of heat loss, we measured oxygen consumptions (VO2), skin-surface temperatures (Tskin, an index of heat release), blood flows in the tails, and rectal temperatures (Trectal) of mice housed in an animal room under the standard thermal condition of similar to 23 degrees C. Compared with wild-type (Ucp1(+/+)) mice, adult UCP1-deficient (Ucp1(-/-)) mice tended to show a reduced VO2. Thermograhic analysis of the acute response of Ucp1(-/-) mice to a small change (a drop of 1-2 degrees C) in the ambient temperature revealed a sustained fall in the Tskin of Ucp1(-/-) mice; but this fall was only transient in Ucp1(+/+) mice. Analysis of tail blood flow under anesthesia clearly showed a stronger vasoconstrictor response in Ucp1(-/-) mice than in Ucp1(+/+) mice. Administration of a vasodilator, evodiamine, transiently increased Tskin in Ucp1(+/+) and Ucp1(-/-) mice similarly; whereas the induction of vasodilation caused a greater and more prolonged reduction in Trectal in Ucp1(-/-) mice than in Ucp1(+/+) mice. These results indicate that Ucp1 (-/-) mice highly, or at least partly, rely on vasoconstriction for heat conservation to compensate for their UCP1 deficiency and to maintain homeothermy under the condition of normal housing temperature.
  • K Inokuma, Y Okamatsu-Ogura, A Omachi, Y Matsushita, K Kimura, H Yamashita, M Saito
    AMERICAN JOURNAL OF PHYSIOLOGY-ENDOCRINOLOGY AND METABOLISM 290 5 E1014 - E1021 2006年05月 [査読有り][通常論文]
     
    Mitochondrial uncoupling protein-1 ( UCP1) has been thought to be a key molecule for thermogenesis during cold exposure and spontaneous hyperphagia and thereby in the autonomic regulation of energy expenditure and adiposity. However, UCP1 knockout ( KO) mice were reported to be cold intolerant but unexpectedly did not get obese even after hyperphagia, implying that UCP1 may not be involved in the regulation of adiposity. Treatment of obese animals with beta(3)-adrenergic agonists is known to increase lipid mobilization, induce UCP1, and, finally, reduce body fat content. To obtain direct evidence for the role of UCP1 in the anti-obesity effect of beta(3)-adrenergic stimulation, in the present study, UCP1-KO and wild-type ( WT) mice were fed on cafeteria diets for 8 wk and then given a beta(3)-adrenergic agonist, CL-316,243 ( CL), or saline for 2 wk. A single injection of CL increased whole body oxygen consumption and brown fat temperature in WT mice but not in KO mice, and it elicited almost the same plasma free fatty acid response in WT and KO mice. WT and KO mice increased similarly their body and white fat pad weights on cafeteria diets compared with those on laboratory chow. Daily treatment with CL resulted in a marked reduction of white fat pad weight and the size of adipocytes in WT mice, but not in KO mice. Compared with WT mice, KO mice expressed increased levels of UCP2 in brown fat but decreased levels in white fat and comparable levels of UCP3. It was concluded that the anti-obesity effect of beta(3)-adrenergic stimulation is largely attributable to UCP1, but less to UCP2 and UCP3, and thereby to UCP1-dependent degradation of fatty acids released from white adipose tissue.
  • K Ishioka, A Omachi, M Sagawa, H Shibata, T Honjoh, K Kimura, M Saito
    RESEARCH IN VETERINARY SCIENCE 80 2 127 - 132 2006年04月 [査読有り][通常論文]
     
    Adiponectin is a protein synthesized and secreted by adipocytes. Decreased adiponectin is responsible for insulin resistance and atherosclerosis associated with human obesity. We obtained a cDNA clone corresponding to canine adiponectin, whose nucleotide and deduced amino acid sequences were highly identical to those of other species. Adiponectin mRNA was detected in adipose tissues, but not in other tissues, of dogs. When 22 adult beagles were given a high-energy diet for 14 weeks, they became obese, showing heavier body weights, higher plasma leptin concentrations, but lower plasma adiponectin concentrations. The adiponectin concentrations of plasma samples collected from 71 dogs visiting veterinary practices were negatively correlated to plasma leptin concentrations, being lower in obese than non-obese dogs. These results are compatible with those reported in other species, and suggest that adiponectin is an index of adiposity and a target molecule for Studies on diseases associated with obesity in dogs. (c) 2005 Elsevier Ltd. All rights reserved.
  • D Yamaji, K Kimura, A Watanabe, Y Kon, T Iwanaga, MM Soliman, MM Ahmed, M Saito
    DOMESTIC ANIMAL ENDOCRINOLOGY 30 3 239 - 246 2006年03月 [査読有り][通常論文]
     
    Hepatocyte growth factor/scatter factor (HGF/SF) is a pleiotropic cytokine that plays a crucial role in the embryonic and postnatal development of various organs including the mammary gland. We cloned bovine HGF and its c-Met receptor cDNAs, and examined their expression during mammary gland development in dairy cows. The 2.5-kbp HGF cDNA clone contained a 2190 bp open reading frame coding a 730 amino acid protein, while the 4.8-kbp c-Met cDNA clone contained a 4152 bp open reading frame coding a 1384 amino acid protein. The bovine HGF and c-Met sequences exhibited more than 87% identity with those of other mammals. RT-PCR analysis revealed ubiquitous expression of both HGF and c-Met mRNAs in various bovine tissues tested. HGF mRNA was detected only in the inactive stage of bovine mammary gland development and not in the developing, lactating, and involuting stages, while c-Met mRNA was detected in the inactive and involuting stages. Immunohistochemical analysis demonstrated that the c-Met protein was found on mammary epithelial cells in the inactive, developing, and involuting stages, and on myoepithelial cells in all stages. These results suggest pivotal roles of HGF and c-Met in the development of bovine mammary gland. (c) 2005 Elsevier Inc. All rights reserved.
  • K Kimura, A Niijima, R Yoshida, T Kitamura, A Kamikawa, DT Furuya, N Kitamura, A Konno, H Nakamoto, N Sakane, T Yoshida, M Saito
    PEPTIDES 26 12 2547 - 2553 2005年12月 [査読有り][通常論文]
     
    The aim of this study was to examine the effect of proinsulin C-peptide on the autonomic nervous systems in rats. Intravenous administration of C-peptide gradually increased electrophysiological activity of the vagus nerves into the stomach and pancreas for at least 90 min. It also slightly increased gastric acid secretion that was suppressed by the treatment with atropine. Intraperitoneal injection of C-peptide did not affect the basal and stress-induced norepinephrine (NE) turnover rate, a biochemical index of sympathetic nerve activity. These results indicate that C-peptide increases parasympathetic nerve activity without affecting sympathetic nerve activity. This could explain, at least in part, the ameliorating effects of C-peptide on impaired cardiac autonomic nerve functions in patients with type I diabetes. (c) 2005 Elsevier Inc. All rights reserved.
  • MC Moore, K Kimura, H Shibata, T Honjoh, M Saito, CA Everett, MS Smith, AD Cherrington
    AMERICAN JOURNAL OF PHYSIOLOGY-ENDOCRINOLOGY AND METABOLISM 289 2 E225 - E231 2005年08月 [査読有り][通常論文]
     
    Intraportal serotonin infusion enhances net hepatic glucose uptake (NHGU) during glucose infusion but blunts nonhepatic glucose uptake and can cause gastrointestinal discomfort and diarrhea at high doses. Whether the serotonin precursor 5-hydroxytryptophan (5-HTP) could enhance NHGU without gastrointestinal side effects during glucose infusion was examined in conscious 42-h-fasted dogs, using arteriovenous difference and tracer ([3-H-3]glucose) techniques. Experiments consisted of equilibration (-120 to -30 min), basal (-30 to 0 min), and experimental (EXP; 0-270 min) periods. During EXP, somatostatin, fourfold basal intraportal insulin, basal intraportal glucagon, and peripheral glucose (to double the hepatic glucose load) were infused. In one group of dogs (HTP, n = 6), saline was infused intraportally from 0 to 90 min (P1), and 5-HTP was infused intraportally at 10, 20, and 40 mu g.kg(-1).min(-1) from 90 to 150 (P2), 150 to 210 (P3), and 210 to 270 (P4) min, respectively. In the other group ( SAL, n = 7), saline was infused intraportally from 0 to 270 min. NHGU in SAL was 14.8 +/- 1.9, 18.5 +/- 2.3, 16.3 +/- 1.4, and 19.7 +/- 1.6 mu mol.kg(-1).min(-1) in P1-P4, whereas NHGU in 5-HTP averaged 16.4 +/- 2.6, 18.5 +/- 1.4, 20.8 +/- 2.0, and 27.6 +/- 2.6 mu mol.kg(-1).min(-1) (P < 0.05 vs. SAL). Nonhepatic glucose uptake (mu mol.kg(-1).min(-1)) in SAL was 30.2 +/- 4.3, 36.8 +/- 5.8, 44.3 +/- 5.8, and 54.6 +/- 11.8 during P1-P4, respectively, whereas in HTP the corresponding values were 26.3 +/- 6.8, 44.9 +/- 10.1, 47.5 +/- 11.7, and 51.4 +/- 13.2 (not significant between groups). Intraportal 5-HTP enhances NHGU without significantly altering nonhepatic glucose uptake or causing gastrointestinal side effects, raising the possibility that a related agent might have a role in reducing postprandial hyperglycemia.
  • H Shibata, R Akahane, T Honjoh, M Asano, K Mominoki, K Fujii, M Suzuki, N Ohtaishi, K Ishioka, M Ahmed, M Soliman, K Kimura, M Saito
    JOURNAL OF EXPERIMENTAL ZOOLOGY PART A-COMPARATIVE EXPERIMENTAL BIOLOGY 303A 7 527 - 533 2005年07月 [査読有り][通常論文]
     
    Several reports have been published on blood leptin concentrations in feral animals, including members of the Carnivora, using a commercially available multi-species radioimmunoassay (RIA) kit with anti-human leptin antibody. However, we observed weak immunoreactivity between recombinant canine leptin and anti-human leptin antibody, suggesting a limitation in the applicability of the RIA kit for leptin assays in Carnivora species. We tested the applicability of RIA and sandwich enzyme-linked immunosorbent assay (ELISA) with anti-canine leptin antibody to assay blood leptin in the dog (Canis familiaris) and the raccoon (Procyon lotor). When RIA was used for recombinant canine leptin and dog sera, values were much lower than those determined by ELISA at higher concentrations (> 10 ng/ml), while rather higher at lower concentrations (< 2ng/ml). A similar discrepancy between the two methods was found for serum leptin concentrations in raccoons. Clear seasonal variations were observed by ELISA, but not by RIA, with high values in autumn (3.46 +/- 0.45ng/ml) and low values in spring and summer (0.71 +/- 0.07ng/ml). Serum leptin concentrations in raccoons correlated positively with their body weight (r = 0.753) and body mass index (r = 0.755), corroborating our previous findings of a strong positive correlation between serum leptin concentrations and body fat content in dogs. Thus, the canine leptin ELISA is useful for assays of dog and raccoon leptin, and blood leptin is a good marker of nutritional condition in the species of Carnivora assayed in this study. (c) 2005 Wiley-Liss, Inc.
  • Y Kontani, Y Wang, K Kimura, KI Inokuma, M Saito, T Suzuki-Miura, Z Wang, Y Sato, N Mori, H Yamashita
    AGING CELL 4 3 147 - 155 2005年06月 [査読有り][通常論文]
     
    Loss of nonshivering thermogenesis in mice by inactivation of the mitochondrial uncoupling protein gene (Ucp1(-/-) mice) causes increased sensitivity to cold and unexpected resistance to diet-induced obesity at a young age. To clarify the role of UCP1 in body weight regulation throughout life and influence of UCP1 deficiency on longevity, we longitudinally analyzed the phenotypes of Ucp1(-/-) mice maintained in a room at 23 degrees C. There was no difference in body weight and lifespan between genotypes under the standard chow diet condition, whereas the mutant mice developed obesity with age under the high-fat (HF) diet condition. Compared with Ucp1(+/+) mice, Ucp1(-/-) mice showed increased expression of genes related to thermogenesis and fatty acid metabolism, such as beta 3-adrenergic receptor, in adipose tissues of the 3-month-old mutants; however, the augmented expression was reduced in Ucp1(+/+) mice in 11-month-old Ucp1(-/-) mice fed the HF diet. Likewise, the increased levels of UCP3 and cAMP-dependent protein kinase in the brown adipose tissue of Ucp1(-/-) mice given the standard diet were decreased significantly in that of Ucp1(-/-) mice fed the HF diet, which animals showed impaired norepinephrine-induced lipolysis in their adipose tissues. These results suggest profound attenuation of beta-adrenergic responsiveness and fatty acid utilization in Ucp1(-/-) mice fed the HF diet, bringing them to late-onset obesity. Our findings provide evidence that UCP1 is neither essential for body weight regulation nor for longevity under conditions of standard diet and normal housing temperature, but deficiency increases susceptibility to obesity with age in combination with HF diet.
  • K Inokuma, Y Ogura-Kamatsu, C Toda, K Kimura, H Yamashita, M Saito
    DIABETES 54 5 1385 - 1391 2005年05月 [査読有り][通常論文]
     
    Sympathetic stimulation activates glucose utilization in parallel with fatty acid oxidation and thermogenesis in brown adipose tissue (BAT) through the beta-adrenergic receptors. To clarify the roles of the principal thermogenic molecule mitochondrial uncoupling protein 1 (UCP1) in the sympathetically stimulated glucose utilization, we investigated the uptake of 2-deoxyglucose (2-DG) into BAT and some other tissues of UCP1-knockout (KO) mice in vivo. In wild-type (WT) mice, administration of norepinephrine (NE) accelerated the disappearance of plasma 2-DG and increased 2-DG uptake into BAT and heart without any rise of plasma insulin level. In UCP1-KO mice, the stimulatory effect of NE on 2-DG uptake into BAT, but not into heart, disappeared completely. Insulin administration increased 2-DG uptake into BAT and also heart similarly in WT and UCP1-KO mice. NE also increased the activity of AMP-activated protein kinase (AMP kinase) in BAT of WT but not UCP1-KO mice. Our results, together with reports that the activation of AMP kinase increases glucose transport in myocytes, suggest that the sympathetically stimulated glucose utilization in BAT is due to the serial activation of UCP1 and AMP kinase.
  • Kimura K
    Seikagaku. The Journal of Japanese Biochemical Society 77 419 - 423 5 2005年05月 [査読有り][通常論文]
  • K Ishioka, M Okumura, M Sagawa, F Nakadomo, K Kimura, M Saito
    VETERINARY RADIOLOGY & ULTRASOUND 46 1 49 - 53 2005年01月 [査読有り][通常論文]
     
    Obesity is the most common nutritional disorder in small animals. To establish a computed tomogmphic (CT) method for assessment of visceral and subcutaneous fat content in the dog, CT analysis was performed in normal and obese beagles. Fat area was measured by the level detection method at varied attenuation ranges and compared with body fat content estimated by the deuterium oxide dilution method. Fat area measured at L3 using the attenuation range of -135/-105 Hounsfield unit had the best correlation with body fat content (r=0.98). Regional fat distribution was almost the same between normal and obese dogs with more fat accumulation at L1-S1 than T10-T13. Moreover, visceral and subcutaneous fat area could be estimated separately. This CT method may contribute to both the clinical diagnosis and the study of canine obesity. especially for studies in the relationship between body fat distribution and obesity-associated diseases.
  • K Ishioka, H Hatai, K Komabayashi, MM Soliman, H Shibata, T Honjoh, K Kimura, M Saito
    VETERINARY JOURNAL 169 1 85 - 90 2005年01月 [査読有り][通常論文]
     
    Leptin is a protein synthesized and secreted primarily by adipocytes, and plays a key role in the regulation of energy balance. We have reported that serum leptin is elevated in obese dogs. In the present study, we examined diurnal variations of serum leptin in the dog, with special references to feeding and fasting cycles. Four male beagles were accustomed to feed once a day at 10:00 h, and blood samples were taken every 3 h for 24-36 h. Serum leptin concentration showed clear diurnal variations, being lowest before food intake (2.3 +/- 0.5 ng/mL) at 09:00 h, and highest (10.5 +/- 2.4 ng/mL) at 18:00 h. Such diurnal variations disappeared when the dogs were fasted. Serum insulin also showed diurnal variation with higher levels at 12:00-15:00 h. When insulin or glucose was injected in the fasted dogs to mimic the post-prandial insulin rise, serum leptin concentration was significantly increased in 4-8 h, but in both cases to a lesser extents than those after food intake. The results indicate that serum leptin concentrations change diurnally in association with feeding-fasting cycles in the dog, partially due to changes in insulin secretion. (C) 2004 Elsevier Ltd. All rights reserved.
  • A Ohashi, Y Matsushita, H Shibata, K Kimura, K Miyashita, M Saito
    JOURNAL OF NUTRITIONAL SCIENCE AND VITAMINOLOGY 50 6 416 - 421 2004年12月 [査読有り][通常論文]
     
    Dietary supplementation of conjugated linoleic acids (CLA) is known to have some beneficial effects such as anti-carcinogenic and anti-obesity effects in several animal species, while it also induces insulin resistance and fatty liver. especially in mice. To explore the possible factors responsible for the CLA-induced insulin resistance. we examined the plasma and mRNA expression levels of several adipocytokincs. which are likely involved in the regulation of insulin sensitivity. in normal C57BL mildly obese/diabetic KK and morbidly obese/diabetic KKAy mice. Feeding a diet supplemented with 0.5% CLA oil consisting of 30.5% c9. t11-CLA and 28.9% t10. c12-CLA for 4 wk resulted in a decrease in white adipose tissue (WAT). an increase in liver weight with excess accumulation of triglyceride and insulin resistance associated with hyperglycemia and hyperinsulinemia. The plasma and WAT mRNA levels of leptin were higher in KK and KKAy mice than C57BL mice. whereas those of adiponectin were higher in C57BL mice. CLA-feeding decreased the levels of leptin, adiponectin and resistin. especially in KK and KKAy mice. In contrast, tumor necrosis factor-alpha (TNF alpha) mRNA levels were higher in KK and KKAy mice than C57BL mice. and were increased by CLA feeding. The present results thus indicate that CLA feeding promotes insulin resistance in obese/diabetic mice by at least inverse regulation of leptin and adiponectin, and TNF alpha. adipocytokines known to either ameliorate or deteriorate insulin sensitivity respectively.
  • Z Shaban, S El-Shazly, S Abdelhady, Fattouh, I, K Muzandu, M Ishizuka, K Kimura, A Kazusaka, S Fujita
    JOURNAL OF VETERINARY MEDICAL SCIENCE 66 11 1377 - 1386 2004年11月 [査読有り][通常論文]
     
    Aryl hydrocarbon receptor (AhR) is a ligand-activated transcription factor that mediates a spectrum of toxic and biological effects of 2,3,7,8-tetrachloro dibenzo-p-dioxin (TCDD) and related compounds. Peroxisome proliferator activated receptor alpha (PPARalpha) is a nuclear receptor involved in the maintenance of lipid and glucose homeostasis. In this study we hypothesized that one of the possible mechanisms for the effect of TCDD and its related chemicals on fat metabolism could be through down regulation of PPARalpha functions. We treated Wistar rats with an AhR ligand, Sudan III (S.III), and/or PPARalpha ligand, Clofibric Acid (CA), for 3 days. We analysed the expression of one of the PPARalpha-target gene products, CYP4A protein and its mRNA. We also tested HepG2 cells with the afore-mentioned treatments and evaluated their effects on PPARalpha and RXRalpha protein. Treatment of Wistar rats with S.III was found to down regulates CYP4A protein expression and reduced its induction with CA. It also decreased mRNA expressions of CYP4A1, CYP4A2, CYP4A3 and PPARalpha. In HepG2 cells, PPARalpha and RXRalpha protein expression was decreased by S.III treatment in a dose dependent manner. Our results suggest that AhR has an inhibitory effect on PPARa function and a new pathway by which AhR ligands could disturb lipid metabolism.
  • Z Shaban, S El-Shazly, M Ishizuka, K Kimura, A Kazusaka, S Fujita
    ARCHIVES OF TOXICOLOGY 78 9 496 - 507 2004年09月 [査読有り][通常論文]
     
    Fibrates, hypolipidemic drugs, have been reported to suppress the metabolic activities of cytochrome P450 1A1 and 1A2 in rats but the mechanism has not been elucidated. In the present study we tested the hypothesis that the inhibitory effect of fibrates on arylhydrocarbon receptor (AhR) function may be due to their stimulatory effects on PPARalpha. Sudan III (S.III) treatment induced CYP 1A1 and CYP 1A2 protein expression, mRNA and their metabolic activities, methoxyresorufin-O-demethylase (MROD) and ethoxyresorufin-O-deethylase (EROD), in Wistar rats higher than those in the control. Co-treatment of rats with S.III and clofibric acid (CA) caused a 40-50% decrease in the induced levels of CYP1A1 and CYP1A2 protein, mRNA expression and their metabolic activities and reduced AhR protein expression. When we treated HepG2 cells with S.III and/or CA, no suppressive effect on S.III-induced CYP1A1 protein expression due to CA was found. HepG2 cells were transiently transfected with increasing concentrations of PPARalpha mammalian expression vector and exposed to the same treatment. CA co-treatment with S.III decreased AhR protein and S.III-induced CYP1A1 protein expression with increasing dose of PPARalpha transfected into HepG2 cells. Our results demonstrate that the suppressive effect of fibrates on CYP1A is PPARalpha-dependent and suggest that PPARalphahas an inhibitory effect on AhR function.
  • M Soliman, S Okamoto, H Kitamura, S Kushibiki, K Kimura, M Saito
    JAPANESE JOURNAL OF VETERINARY RESEARCH 52 2 95 - 99 2004年08月 [査読有り][通常論文]
     
    The responses of plasma cortisol and adrenocorticotropic hormone (ACTH) were examined to intravenous injection of recombinant bovine tumor necrosis factor-alpha (TNF-alpha) and interferon-gamma (INF-gamma) in Holstein cows. INF-gamma induced dose-dependent rises in the plasma levels of both cortisol and ACTH, while TNF-alpha induced comparable plasma cortisol responses with much smaller rises in plasma ACTH. The results suggest a direct stimulatory action of TNF-alpha on cortisol secretion from the adrenal gland in cattle.
  • D Yamaji, H Kitamura, K Kimura, Y Matsushita, H Okada, T Shiina, M Morimatsu, M Saito
    VETERINARY IMMUNOLOGY AND IMMUNOPATHOLOGY 98 3-4 175 - 184 2004年04月 [査読有り][通常論文]
     
    Molecule possessing ankyrin-repeats induced by lipopolysaccharide (MAIL) is known as an IkappaB protein induced after administration of bacterial lipopolysaccharide, (LPS) to mice. In the present study, we cloned bovine MAIL cDNA and examined its mRNA expression in white blood cells isolated from Holstein cows. Bovine MAIL had more than 80% amino acid identities with murine and human MAILs, highly conserved ankyrin-repeat motifs and PEST-like sequences. Bovine MAIL mRNA was undetectable in isolated peripheral white blood cells, but rapidly induced (< 1h) after stimulation by LPS and lipid A in vitro in a dose-dependent manner. The lipid A-induced MAIL mRNA expression was found in polymorphonuclear cells, monocytes/macrophages and total lymphocytes, but not in T-lymphocytes. MAIL mRNA was also induced in vivo in peripheral blood leukocytes of cows after intramammary injection of Escherichia coli derived from coliform, mastitis. Thus, bovine MAIL, as rodent MAILs, is induced by inflammatory stimuli in specific immune cells in vitro and in vivo, suggesting a role in inflammatory responses to bacterial infection in cattle. (C) 2003 Elsevier B.V. All rights reserved.
  • H Nakamoto, N Sakane, K Kimura, T Yoshida, S Mochizuki, Y Ogasawara, F Kajiya
    METABOLISM-CLINICAL AND EXPERIMENTAL 53 3 335 - 339 2004年03月 [査読有り][通常論文]
     
    The aims of the present study are (1) to examine whether coronary flow is increased and (2) to examine the role of C-peptide in relation to nitric oxide (NO) production and coronary flow in a rat heart (Wistar) during the early stages of type 1 diabetes. Coronary flow increased by 36.4% +/- 10.6% (P < .05) during the early stages of streptozotocin-induced diabetes of isolated perfused rat hearts, but NO production increased without significance. C-peptide alone did not change coronary flow, but increased NO production in diabetes. In the presence of insulin, C-peptide reversed both flow and NO production to the control level of normal rats (P < .05). In conclusion, during the early stages of type 1 diabetes, coronary flow was increased, and C-peptide in the presence of insulin synergistically normalized the excessive flow and NO production induced by C-peptide to the control level of normal rats. (C) 2004 Elsevier Inc. All rights reserved.
  • Fujimoto W, Kimura K, Suzuki M, Syuto B, Onuma M, Iwanaga T
    The Journal of veterinary medical science / the Japanese Society of Veterinary Science 66 3 291 - 294 3 2004年03月 [査読有り][通常論文]
  • Makondo K, Kimura K, Kitamura T, Yamaji D, Dong Jung B, Shibata H, Saito M
    Biochimica et biophysica acta 1644 9 - 15 1 2004年02月 [査読有り][通常論文]
  • Shibata H, Sasaki N, Honjoh T, Ohishi I, Takiguchi M, Ishioka K, Ahmed M, Soliman M, Kimura K, Saito M
    The Journal of veterinary medical science / the Japanese Society of Veterinary Science 65 11 1207 - 1211 11 2003年11月 [査読有り][通常論文]
  • K Makondo, K Kimura, N Kitamura, T Kitamura, D Yamaji, BD Jung, M Saito
    BIOCHEMICAL JOURNAL 374 1 63 - 69 2003年08月 [査読有り][通常論文]
     
    Hepatocyte growth factor (HGF) causes endothelium-dependent vasodilation, but its relation to endothelial nitric oxide synthase (eNOS) activity remains to be elucidated. Treatment of bovine aortic endothelial cells with HGF increased eNOS activity within minutes, accompanied by an increase of activity-related site-specific phosphorylation of eNOS. The phosphorylation was completely abolished by pretreatment of the cells with a phosphoinositide 3-kinase (PI3K) inhibitor (wortmannin) and by transfection of dominant-negative Akt, and the enzyme activity was inhibited by wortmannin. In addition, eNOS activity and phos phorylation were abolished by pretreatment of the cells with an intracellular Ca2+-chelator, bis-(o-aminophenoxy)ethane-N,N, N',N'-tetra-acetic acid tetrakis(acetoxymethyl ester) (BAPTA/ AM), with a suppression of Akt phosphorylation. These results suggest that HGF stimulates eNOS activity by a PI3K/Akt-dependent phosphorylation in a Ca2+ -sensitive manner in vascular endothelial cells.
  • K Makondo, K Kimura, T Kitamura, D Yamaji, M Saito
    JAPANESE JOURNAL OF VETERINARY RESEARCH 51 2 105 - 112 2003年08月 [査読有り][通常論文]
     
    Endothelial cells are important for maintenance of vascular integrity by producing a variety of bioactive molecules such as nitric oxide (NO). Recent evidence has suggested that there are some differences in characteristics between endothelial cells from different origins. Here we examined responses of two typical endothelial cells to hepatocyte growth factor (HGF), which induces endothelium-dependent relaxation of microvessels. Stimulation of human umbilical vein endothelial cells (HUVEC) and bovine aortic endothelial cells (BAEC) with HGF increased endothelial NO synthase activity, accompanied with an increase of activity-related site-specific phosphorylation of protein kinase B/Akt. However, HGF stimulated phosphorylation of p38 mitogen-activated protein kinase (MAPK) only in HUVEC, but not in BAEC, while it induced phosphorylation of p44 /p42 MAPK in both cells. These results suggest that HGF transduces different intracellular signals between aortic and umbilical venous endothelial cells, and that the differences might represent divergent endothelial responses to growth factors, especially those that activate receptor-tyrosine kinases.
  • Soliman M, Ishioka K, Yoshida R, Komabayashi K, Hatai H, Matsui Y, Hirai T, Katagiri S, Takahashi Y, Kawakita Y, Abe H, Kitamura H, Kimura K, Saito M
    The Journal of veterinary medical science / the Japanese Society of Veterinary Science 64 11 1053 - 1056 11 2002年11月 [査読有り][通常論文]
  • Soliman M, Ishioka K, Kimura K, Kushibiki S, Saito M
    The Japanese journal of veterinary research 50 107 - 114 2-3 2002年11月 [査読有り][通常論文]
  • K Ishioka, MM Soliman, T Honjoh, H Shibata, K Kimura, M Saito
    VETERINARY JOURNAL 164 3 295 - 297 2002年11月 [査読有り][通常論文]
  • T Kitamura, K Kimura, BD Jung, K Makondo, N Sakane, T Yoshida, M Saito
    BIOCHEMICAL JOURNAL 366 737 - 744 2002年09月 [査読有り][通常論文]
     
    Proinsulin C-peptide has been reported to have some biological activities and to be possibly involved in the development of diabetic microangiopathy. In the present study, we examined the effects of C-peptide on the mitogen-activated protein kinase pathway in LEII mouse lung capillary endothelial cells. Stimulation of the cells with C-peptide increased both p38 mitogen-activated protein kinase (p38MAPK) and extracellular signal-regulated kinase (ERK1/2) activities and activity-related site-specific phosphorylation of the respective kinases in a concentration-dependent manner, but failed to activate c-Jun N-terminal kinase. Stimulation of the cells with C-peptide also induced site-specific phosphorylation of cAMP response element (CRE)-binding protein (CREB)/activating transcription factor 1 (ATF1), and thereby binding of these transcription factors to CRE. Among three CREB kinases tested, phosphorylation of mitogen-activated protein kinase-activated protein kinase 2 (MAPKAPK2) was induced after stimulation with C-peptide. The phosphorylation of CREB, ATF1 and MAPKAP-K2 were inhibited by SB203580, a p38MAPK inhibitor, but not by PD98059, an ERK kinase inhibitor. These results indicate that C-peptide activates p38MAPK followed by MAPKAP-K2 to enhance DNA-CREB/ATF1 interactions.
  • W Fujimoto, M Suzuki, K Kimura, T Iwanaga
    BIOMEDICAL RESEARCH-TOKYO 23 2 91 - 99 2002年04月 [査読無し][通常論文]
     
    Gut chitinase, originally identified as acidic mammalian chitinase, is secreted from the salivary gland and stomach in humans and mice, but exclusively from the liver in cattle. Since the organs producing gut chitinase differ depending on the species, here we determined the expression site of this enzyme in the gastrointestinal tract of frogs, Xenopus laevis and Rana catesbeiana, which eat a large amount of chitin-coated animals, using in situ hybridization and immunohistochemistry. The chitinase was detected only in the oxynticopeptic cells of gastric glands and was accumulated in secretory granules in the cytoplasm, suggesting that the enzyme may be released into the gastric lumen directly. In addition, the enzyme was not found in the stomach of larvae, but was detected at stage 62 of metamorphosis and later, when the frogs changed from a herbivorous to a carnivorous diet.
  • Ishioka K, Soliman MM, Sagawa M, Nakadomo F, Shibata H, Honjoh T, Hashimoto A, Kitamura H, Kimura K, Saito M
    The Journal of veterinary medical science / the Japanese Society of Veterinary Science 64 4 349 - 353 4 2002年04月 [査読有り][通常論文]
  • N Takahashi, T Kawada, T Goto, T Yamamoto, A Taimatsu, N Matsui, K Kimura, M Saito, M Hosokawa, K Miyashita, T Fushiki
    FEBS LETTERS 514 2-3 315 - 322 2002年03月 [査読有り][通常論文]
     
    Several herbal medicines improve hyperlipidemia, diabetes and cardiovascular diseases. However, the molecular mechanism underlying this improvement has not yet been clarified. In this study, we found that several isoprenols, common components of herbal plants, activate human peroxisome proliferator-activated receptors (PPARs) as determined using the novel GAL4 ligand-binding domain chimera assay system with coactivator coexpression. Farnesol and geranylgeraniol that are typical isoprenols in herbs and fruits activated not only PPARgamma but also PPARalpha as determined using the chimera assay system. These compounds also activated full-length human PPARgamma and PPARalpha in CV1 cells. Moreover, these isoprenols upregulated the expression of some lipid metabolic target genes of PPARgamma and PPARalpha in 3T3-L1 adipocytes and HepG2 hepatocytes, respectively. These results suggest that herbal medicines containing isoprenols with dual action on both PPARgamma and PPARalpha can be of interest for the amelioration of lipid metabolic disorders associated with diabetes. (C) 2002 Federation of European Biochemical Societies. Published by Elsevier Science B.V. All rights reserved.
  • K Ishioka, K Kanehira, N Sasaki, H Kitamura, K Kimura, M Saito
    COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY B-BIOCHEMISTRY & MOLECULAR BIOLOGY 131 3 483 - 489 2002年03月 [査読有り][通常論文]
     
    Uncoupling proteins (UCPs) are members of the mitochondrial transporter family that dissipate the proton gradient as heat more than via ATP synthesis. In the present study, nucleotide and amino acid sequences of UCPs 1, 2 and 3 of a dog were determined, and their mRNA expression in various peripheral tissues was examined. The sequences were highly (76-97%) homologous to those of other species. Although lower homologies (60-74%) were found when compared among the three canine UCPs, their deduced amino acid sequences had some common domains, such as three mitochondrial carrier protein motifs, six transmembrane a-helix domains, and putative purine nucleotide binding domains. By Northern blot analyses, UCP1 mRNA was not detected in any tissues examined. UCP2 mRNA was expressed in most tissues, particularly abundantly in adipose tissue, spleen and lung. Two sizes of UCP3 mRNA were found exclusively in heart and skeletal muscle. These results suggest that canine UCPs have uncoupling activity, and are involved in the regulation of metabolic heat production and/or energy expenditure, as do those of other species. (C) 2002 Elsevier Science Inc. All rights reserved.
  • Energy metabolism and brown adipocyte.
    Pharma Medica 20, 61-67 2002年 [査読無し][通常論文]
  • Effects of fish oil feeding on obesity and UCP expression in dogs.
    Veterinary Biochem. 39, 31-38 2002年 [査読無し][通常論文]
  • イヌの肥満に対する魚油給餌の効果とUCPの発現
    石岡克己, Mohamed Mohamed Soliman, 奥村正裕, 佐川真由美, 柴田治樹, 本庄 勉, 北村 浩, 木村和弘, 斉藤昌之
    獣医生化学 37 19 - 26 2002年 [査読有り][通常論文]
  • N Sasaki, H Shibata, T Honjoh, K Kimura, M Saito, Ohishi, I
    JOURNAL OF VETERINARY MEDICAL SCIENCE 63 10 1115 - 1120 2001年10月 [査読無し][通常論文]
     
    Leptin, the product of the obese (ob) gene. is an adipocyte-derived hormone involved in regulating food intake and energy expenditure in humans and rodents. To determine the primary structure of feline leptin, we cloned the feline leptin cDNA using reverse transcription-polymerase chain reaction (RT-PCR) and rapid amplification of complementary DNA (cDNA) ends (RACE) methods. The full-length feline leptin cDNA was 2935 bp with a 501 bp open reading frame encoding the precursor peptide of 167 amino acids including 21 residues of signal peptide. The sequence of a 146-amino acid mature leptin was 81.5-91.8% homologous to those of other species. RT-PCR analysis revealed that the leptin mRNA was expressed in adipose tissues and not detected in liver, hearth kidney, lung, pancreas, brain and skeletal muscle. These data show that feline leptin is highly homologous to leptins of other species. and expressed in adipose tissues in cats.
  • M Soliman, S Abdelhady, L Fattouh, K Ishioka, H Kitamura, K Kimura, M Saito
    JOURNAL OF VETERINARY MEDICAL SCIENCE 63 10 1143 - 1145 2001年10月 [査読無し][通常論文]
     
    To determine the role of leptin in endotoxin-induced anorexia in ruminants, circulating leptin levels were measured during acute experimental endotoxemia in sheep. Injection of bacterial lipopolysaccharide (450 ng/kg, i.v.) induced anorexia accompanied with fever and increases in serum levels of cortisol, insulin and glucose which are known to stimulate leptin secretion in rodent and human, while it did not affect serum leptin levels at all. These results indicate that serum leptin levels in sheep during acute endotoxemia are differentially regulated from those in rodent and human. and that leptin might not be involved in the endotoxin-induced anorexia in sheep.
  • S Okamoto, K Kimura, M Saito
    NEUROSCIENCE LETTERS 307 3 179 - 182 2001年07月 [査読無し][通常論文]
     
    Leptin is a key afferent signal that decreases food intake and increases energy expenditure by acting on the specific receptors in the hypothalamus. Corticotropin-releasing hormone (CRH) and its homologous peptide, urocortin, are also known to have a potent anorectic effect when given intracranially. To determine possible involvement of these two peptides in the leptin-induced anorexia, in the present study, food intake was measured in rats pretreated with antibodies against CRH and urocortin. In the control rats without antibody pretreatment, intracerebroventricular (icv) injection of leptin (0.1-1 mug/rat) suppressed nocturnal food intake. The anorectic effect of leptin was substantially attenuated in rats pretreated with icy injection of an anti-CRH antibody, but not with an anti-urocortin antibody. These results suggest that the anorectic effect of leptin is mediated by CRH, but not by urocortin, in the hypothalamus. (C) 2001 Elsevier Science Ireland Ltd. All rights reserved.
  • Shiroshita, N, Musashi, M, Sakurada, K, Kimura, K, Tsuda, Y, Ota, S, Iwasaki, H, Miyazaki, T, Kato, T, Miyazaki, H, Shimosaka, A, Asaka, M
    Journal of Pharmacology and Experimental Therapeutics 297 3 868 - 875 2001年06月 [査読無し][通常論文]
     
    We studied the effect of thrombopoietin (TPO) on interleukin-3 (IL-3)-dependent bone marrow cell colony formation of mice to clarify the role of protein kinase C (PKC) in the signal transduction of TPO for the proliferation of primitive hematopoietic progenitors. TPO alone hardly yielded colonies. However, TPO in combination with IL-3 increased colony numbers synergistically from 2- to 4-fold, compared with those supported by IL-3 alone. Serial observation of colony development showed that TPO may hasten the appearance of colonies by shortening the dormant period (G(o)) of primitive progenitors. Immunocytochemical studies on PKC isoforms in progenitor cells stimulated with TPO have revealed that the expression pattern of PKC-epsilon is changed, but not that of PKC-alpha, -beta, -gamma, -delta, or -xi. Selective PKC inhibitors, such as calphostin C and GF 109203X, and PKC-epsilon -specific translocation inhibitor peptide abrogated the enhancing effect of TPO on IL-3-dependent colony formation and the changes in the intracellular expression pattern of PKC-epsilon. These data taken together suggest that TPO has a direct effect on primitive progenitors and enhances IL-3-dependent colony formation, at least partly through the activation of PKC-epsilon.
  • Ishikawa, I, H Kitamura, K Kimura, M Saito
    JAPANESE JOURNAL OF VETERINARY RESEARCH 49 1 19 - 25 2001年05月 [査読無し][通常論文]
     
    Interleukin (IL)-6, a cytokine for host defense responses to infection and imflammation, is known to be induced by non-invasive physical or psychological stress, too. To test possible involvement of brain IL-1 in the stress-induced IL-6 production, IL-1 mRNA expression in the hypothalamus, in parallel with blood IL-6 level, was examined in rats subjected to restriction of their movement (immobilization stress). When rats were immobilized, the hypothalamic IL-1 beta mRNA level was increased in 1 hr, followed by progressive rises in the serum IL-6 level. The immobilization-induced rise in serum IL-6 was mimicked by intracerebroventricular (icv) administration of IL-1 beta under normal conditions, whereas it was attenuated by icv injection of an IL-1 receptor antagonist. These results indicate that IL-1 in the hypothalamus plays a pivotal mediating role in the stress-induced peripheral IL-6 production.
  • T Kitamura, K Kimura, BD Jung, K Makondo, S Okamoto, Canas, X, N Sakane, T Yoshida, M Saito
    BIOCHEMICAL JOURNAL 355 1 123 - 129 2001年04月 [査読無し][通常論文]
     
    It has been demonstrated that proinsulin C-peptide possesses several biological activities and that its specific binding sites are present on the surface of cell membranes. However, the molecular and cellular mechanisms of C-peptide actions are poorly known. In the present study we examined the possible involvement of the mitogen-activated protein kinase (MAPK) pathway in C-peptide effects. C-peptide induced the phosphorylation of MAPK [p44 extracellular signal-regulated kinase 1 (ERK1) and p42 ERK2] in Swiss 3T3 and 3T3-F442A fibroblasts but not in 3T3-L1 fibroblasts and some other cell lines such as L6E9 muscle cells. In Swiss 3T3 cells, C-peptide-induced phosphorylation of MAPK was dependent on time and concentration, being maximal at 1 min and at 1 nM C-peptide and was accompanied by an increase in MAPK activity and MAPK kinase (MEK) phosphorylation. The MAPK phosphorylation by C-peptide was abolished by treatment with pertussis toxin (PTX) and also with a MEK inhibitor, PD 98059. In addition, MAPK phosphorylation was attenuated by treatment with a phosphoinositide 3-kinase (PI-3K) inhibitor. wortmannin, and with a protein kinase C (PKC) inhibitor, GF109203X, and by down-regulation of PKC by prolonged treatment with PMA. Similar effects of the inhibitors and PTX were found on the MAPK phosphorylation induced by neuropeptide Y. These results suggest that C-peptide activates MAPK through a putative G(1)/G(0)-linked receptor for C-peptide and through PI-3K-dependent and PKC-dependent pathways.
  • Interaction of immune cytokines and the sympathetic nerve system: mechanisms of hepatic cytokine induction in stress situations.
    The Autonomic Nervous System 38, 234-241 2001年 [査読無し][通常論文]
  • Enzyme-linked immunosorbent assay of canine leptin and increased serum concentrations in obese beagles.
    Veterinary Biochem. 38, 35-41 2001年 [査読無し][通常論文]
  • S Okamoto, K Kimura, T Kitamura, Canas, X, T Yoshida, M Saito
    DIABETOLOGIA 43 12 1512 - 1517 2000年12月 [査読無し][通常論文]
     
    Aims/hypothesis. To investigate whether proinsulin C peptide influences sympathetic nerve activity directly or indirectly through parasympathetic nerve activity. Methods. The proliferative response of splenic lymphocytes to Concanavalin A (ConA response) which is known to be suppressed by subjection of rats to footshock or intracerebroventricular injection of corticotropin-releasing factor through sympathetic nerve activation was measured. Effect of C peptide alone or before subjection to footshock or injection of corticotropin-releasing factor was examined, Results. Intraperitoneal injection of C peptide was without effect on the basal ConA response, while subjection to footshock or injection of corticotropin-releasing factor lowered it. In contrast, prior injection of C peptide obviated the footshock and corticotropin-releasing factor-induced suppression of the response. When given intracerebroventricularly, C peptide was also effective at much smaller doses. Prior injection of atropine cancelled the C-peptide effects. Conclusion/interpretation. Our results indicate that C peptide counteracts the sympathetic nerve-mediated suppression of splenic lymphocyte proliferation in an atropine-sensitive manner. Thus, C peptide probably activates the parasympathetic nervous system through the afferent mechanism, that in turn antagonizes the sympathetic nerve-mediated suppression of splenic lymphocyte functions.
  • Jung, B. D, Kimura, K, Kitamura, H, Makondo, K, Kanehira, K, Saito, M
    Journal of Veterinary Medical Sciences 62 4 409 - 413 2000年04月 [査読無し][通常論文]
     
    Interleukin (IL)-1 beta mRNA expression in the liver and spleen was examined after subjection to oscillation stress in the rat. Thirty-minute subjection to oscillation stress increased IL-1 beta mRNA expression in the both organs. Prior treatment of rats with gadolinium chloride, which eliminates macrophages, prevented the stress-induced IL-1 beta expression. Either adrenalectomy or treatment of guanethidine, a blocker of norepinephrine release in the sympathetic nerve endings, partially attenuated the stress-induced response, but the combined treatment completely blocked it. Injection of beta-adrenergic antagonist (propranolol) also suppressed the stress-induced response. These results suggest that oscillation stress induces IL-1 beta mRNA expression in the liver and spleen, probably in Kupffer cells and splenic macrophages, and that stress-induced IL-1 beta expression is elicited by catecholamines released from sympathetic nerve terminals and the adrenal gland.
  • R Komagome, K Kimura, M Saito
    JAPANESE JOURNAL OF VETERINARY RESEARCH 47 3-4 127 - 133 2000年02月 [査読無し][通常論文]
     
    To provide information on the role of Rho, a GTP-binding protein, in postnatal development of the brain cells, the change in the levels of Rho protein and Rho-related proteins was examined in the brain of mice for two weeks after birth, in parallel with the changes in the activity of marker enzymes for neuronal and glial cells. The activities of acetylcholine esterase and choline acetyltransferase of whole brain homogenate, both of which are neuronal marker enzymes, were progressively increased in an age-dependent manner. The activity of 2',3'-cyclic nucleotide 3'-phosphohydrolase, a glial marker enzyme, increased markedly between one and two weeks after birth. In contrast, the levels of RhoA and RhoB in the membrane fraction were decreased during the postnatal period. The amount of Rho GDP dissociation inhibitor, a regulatory protein for Rho, was unchanged, while those of Rho target proteins, Rock-2 and citron, were gradually increased. Since the inactivation of Rho is known to induce neurite extension and neuronal and glial differentiation in vitro, our results suggest that the Rho signalling pathway plays a regulatory role in the postnatal differentiation of neuronal and glial cells in vivo.
  • M Iwase, K Kimura, R Komagome, N Sasaki, K Ishioka, T Honjoh, M Saito
    JOURNAL OF VETERINARY MEDICAL SCIENCE 62 2 207 - 209 2000年02月 [査読無し][通常論文]
     
    Leptin is the ob gene product secreted from adipocytes in mammals, and thereby its plasma level reflects body fat content. To establish an assay method for leptin in the dog, rabbit anti-canine leptin antibody was obtained using canine recombinant leptin as an antigen. This antibody reacted to canine leptin much stronger than mouse, rat and human leptins. Sandwich enzyme-linked immunosorbent assay (ELISA) using this antibody was developed. The serum leptin levels of 13 healthy dogs were in a range from 1.4 to 5.6 ng/ml with the mean +/- SEM of 3.0 +/- 0.3 ng/ml.
  • S Okamoto, Y Irie, Ishikawa, I, K Kimura, M Saito
    BRAIN RESEARCH 855 1 192 - 197 2000年02月 [査読無し][通常論文]
     
    Leptin is one of the key afferent signals that regulate food intake and energy expenditure by acting on specific receptors in the hypothalamus. Recently, leptin was reported to activate the peripheral immune system by acting directly on lymphocytes. To elucidate the brain-mediated participation of leptin in the modulation of peripheral immune functions, we examined the effects of intracerebroventricular (icv) injection of murine recombinant leptin on the proliferative response to Concanavalin A (ConA response) of splenic lymphocytes in rats. The ConA response of splenic lymphocytes was markedly reduced 30 min after icy injection of leptin. The suppressive effect of leptin was abolished completely either by surgical severing of the splenic nerves or by icy injection of an antibody against corticotropin-releasing hormone (CRH), but only partially by an anti-urocortin antibody. Icy injection of CRH and urocortin also suppressed the ConA response of splenic lymphocytes, and the effect of urocortin was prevented by the anti-CRH antibody, while that of CRH was not prevented by the anti-urocortin antibody. These results suggest that leptin suppresses peripheral lymphocyte functions, in contrast to the direct activating effects, indirectly through the activation of the CRH (urocortin)-sympathetic nervous system. (C) 2000 Elsevier Science B.V. All rights reserved.
  • BD Jung, K Kimura, H Kitamura, K Makondo, K Okita, M Kawasaki, M Saito
    JOURNAL OF BIOCHEMISTRY 127 2 205 - 209 2000年02月 [査読無し][通常論文]
     
    Non-invasive immobilization stress causes an increase in the plasma interleukin (IL)-6 level accompanied by increased IL-6 mRNA expression and IL-6 immunoactivity in the liver [Biochem. Biophys. Res. Commun, (1997) 238, 707-711]. In the present study, using rat primary cultured hepatocytes and non-parenchymal liver cells, the effect of norepinephrine (NE) on IL-6 mRNA expression was determined. IL-6 mRNA expression in hepatocytes, but not in non-parenchymal liver cells, increased when the cells were treated with NE, The stimulatory effect of NE was inhibited by the combined use of alpha-and beta-adrenergic antagonists. IL-6 mRNA expression in hepatocytes also increased on incubation with the culture medium of non-parenchymal liver cells treated with NE, The effect of the medium was blocked by an IL-1 receptor antagonist. Moreover, exogenous IL-1 beta stimulated IL-6 mRNA expression in hepatocytes. IL-1 beta was present in the medium of non-parenchymal liver cells and increased with NE-treatment. These results suggest that NE released from sympathetic nerve terminals during stress can directly increase ILS mRNA expression in hepatocytes and indirectly through IL-1 beta production from non-parenchymal liver cells.
  • Canine uncoupling proteins : cDNA cloning and tissue distribution.
    Veterinary Biochem. 37 65 - 72 2000年 [査読無し][通常論文]
  • Sympathetic regulation of hepatic interleukin expression in the rat.
    Animal Biochem. 36 21 - 28 2000年 [査読無し][通常論文]
  • Canine leptin : molecular cloning, expression and functional properties of recombinant protein.
    Iwase, M, Kimura, K, Sasaki, N, Komagome, R, Ishioka, K, Morimatsu, M, Murakami, T, Saito, M
    Research in Veterinary Science 68 109 - 114 2000年 [査読無し][通常論文]
  • Mutated human β3-adrenergic receptor (Trp64Arg)lowers the response to β3-adrenergic agonists in transfected 3T3-L1 preadipocytes.
    Kimura, K, Sasaki, N, Asano, A, Mizukami, J, Kayahashi, S, Kawada, T, Fushiki, T, Morimatsu, M, Yoshida, T, Saito, M
    Hormone and Metabolic Research 36 91 - 96 2000年 [査読無し][通常論文]
  • Nagase, I, S Yoshida, Canas, X, Y Irie, K Kimura, T Yoshida, M Saito
    FEBS LETTERS 461 3 319 - 322 1999年11月 [査読無し][通常論文]
     
    Uncoupling protein 3 (UCP3), expressed abundantly in the skeletal muscle, is one of the carrier proteins dissipating the transmitochondrial electrochemical gradient as heat, and thereby has been implicated in the regulation of energy metabolism. We have investigated UCP3 mRNA expression in the widely used L6 myocyte cell line by Northern blot analysis. UCP3 mRNA was not detected in L6 myoblasts, but appeared after their differentiation to myotubes, The UCP3 mRNA level was increased when L6 myotubes were treated with increasing concentrations of triiodothyronine (T3), oleic acid, alpha-bromopalmitate and carbacyclin, a non-selective ligand of peroxisome proliferator-activated receptors (PPARs), whereas it was not influenced when treated with selective ligands of PPAR alpha (WY 14 643) and PPAR gamma (troglitazone), A ligand of retinoid X receptor (RXR), 9-cis retinoic acid, was also effective by itself and in combination with carbacyclin in stimulating UCP3 mRNA expression, The mRNA analysis of individual PPAR isoforms revealed that L6 cell expressed a significant level of PPAR delta but undetectable levels of PPAR alpha and PPAR gamma. These results suggest that UCP3 expression in myocytes is differentiation-dependent and regulated by the T3 receptor, RXR and PPAR delta. (C) 1999 Federation of European Biochemical Societies.
  • R Komagome, B Shuto, K Moriishi, K Kimura, M Saito
    NEUROPATHOLOGY 19 3 288 - 293 1999年09月 [査読有り][通常論文]
     
    Exoenzyme C3 (C3) produced by Clostridium botulinum type C and D strains specifically modifies the small GTP, binding protein Rho. It has been reported that C3 induces neuronal differentiation of the PC12 cell, an adrenergic cell line. In this study, the effects of C3 on a cholinergic cell line (NG108-15) and a glioma (CG) were examined for their differentiation. Treatment of NG108-15 cells and C6 glioma cells with C3 for 3 days induced neurite or process formation. Moreover, treatment by C3 increased the activities of acetylcholine esterase and choline acetyltransferase in NG108-15 cells, and 2',3'-cyclic nucleotide 3'-phosphohydrolase in C6 cells. These results suggest that C3 induces neuronal differentiation of the cholinergic cell as well as the adrenergic cell, and also glial differentiation of the glioma cell.
  • A Asano, K Kimura, M Saito
    JOURNAL OF VETERINARY MEDICAL SCIENCE 61 4 403 - 409 1999年04月 [査読無し][通常論文]
     
    Brown adipose tissue (BAT) is the major site of non-shivering thermogenesis in rodents. Rapid angiogenesis is induced in association with adaptive hyperplasia of this tissue when the animal is exposed to cold. We demonstrated previously adrenergic activation of mRNA expression of vascular endothelial growth factor (VEGF) in rat BAT and its possible contribution to the cold-induced angiogenesis in this tissue. In the present study, we examined the effect of cold exposure on mRNA expression of other two angiogenic factors. VEGF-B and basic fibroblast growth factor (bFGF), in rats. Conventional Northern blot analysis revealed abundant mRNA expression of VEGF-B as well as VEGF, but not bFGF, in BAT. When rats were exposed to cold at 4 degrees C, the VEGF mRNA level was increased by 2.7-fold in 1-4 hr and returned to the basal level within 24 hr. In contrast, the VEGF-B mRNA level did not change throughout the course of cold exposure. A significant expression of bFGF mRNA was detected in BAT by reverse transcription polymerase chain reaction (RT-PCR). To evaluate the tissue bFGF mRNA level quantitatively, a competitive RT-PCR method was developed using a shorter RNA fragment as a competitor. The bFGF mRNA level in BAT was found to increase by 2.3-fold in 4 hr and decreased to the basal level within 24 hr after cold exposure. These results suggest that cold exposure leads to induce VEGF and bFGF rapidly and transiently in BAT, which in turn stimulate the proliferation of vascular endothelial cells in this tissue.
  • BH White, K Kimura, A Sidhu
    NEUROENDOCRINOLOGY 69 3 209 - 216 1999年03月 [査読無し][通常論文]
     
    We have previously found that the D-5 dopamine receptor couples to a G-protein other than G(s)alpha, and could be involved in signaling pathways other than regulation of adenylyl cyclase. To describe interactions of the D-5 receptor with cellular effecters, we used GH(4)C(1) cells transfected with cDNA for the human Dg receptor. Thyrotropin-releasing hormone (TRH, 100 nM) stimulated accumulation of inositol phosphates (IPs) fivefold in D(5)GH(4)C(1) cells. Dopamine (DA, 10 mu M) inhibited TRH-stimulated IP values by 29%; at higher concentrations (100 mu M), maximal inhibition of 61% was observed. The D-5 agonist SKF R-38393 (10 mu M) mimicked this effect (28% inhibition). SCH 23390, a D-5 antagonist, blocked the inhibition caused by both DA and SKF R-38393, Spiperone, a D-2 receptor antagonist, did not block the inhibition. The D-2 agonist (+/-)-2-(N-phenylethyl-N-propyl)amino-5-hydroxytetralin (PPHT) did not inhibit TRH-stimulated IP production, nor did it augment the effect of D-5 agonists. The DA-mediated suppression of IP levels was not sensitive to pertussis toxin; cholera toxin blocked both TRH stimulation and DA suppression of IP accumulation in response to 100 nM TRH. Neither dibutyryl cAMP nor forskolin lowered IP formation in response to TRH. Phorbol ester decreased TRH-stimulated IP accumulation in D(5)GH(4)C(1) cells; however, an inhibitor of protein kinase C (PKC) did not block the effect of DA.
  • Sidhu, A, Olde, B, Humblot, N, Kimura, K, Gardner, N
    Neuroscience Letter 91 2 537 - 547 1999年 [査読無し][通常論文]
  • Kimura, K, Jung, B. D, Kanehira, K, Irie, Y, Cañas, X, Saito, M
    FEBS Letters 457 1 75 - 79 1999年 [査読無し][通常論文]
  • S Okamoto, Ishikawa, I, K Kimura, M Saito
    NEUROREPORT 9 18 4035 - 4039 1998年12月 [査読無し][通常論文]
     
    To assess the possible role of urocortin, a recently identified neuropeptide related to corticotropin-releasing factor (CRF), in modulation of peripheral immune functions, the effects of intracranially administrated urocortin on the proliferative activity of splenic lymphocytes were examined in rats; Intracerebroventricular (i.c.v.) injection of urocortin (1 ng) produced a marked decrease in the proliferative response of splenocytes to a mitogen. The suppressive effect of urocortin was abolished by pretreatment with a ganglionic blocking agent (chlorisondamine) or a beta-adrenergic receptor antagonist (propranolol), but not by adrenalectomy. These results suggest that urocortin is an important neuropeptide involved in the brain control of peripheral immune functions such as stress-induced immunosuppression, and that the suppressive effect of urocortin is mediated by the sympathetic nervous system. (C) 1998 Lippincott Williams & Wilkins.
  • A Sidhu, K Kimura, M Uh, BH White, S Patel
    JOURNAL OF NEUROCHEMISTRY 70 6 2459 - 2467 1998年06月 [査読無し][通常論文]
     
    We have demonstrated previously that D1 dopamine receptors are coupled to both G(s) alpha and G(s) alpha. We examine here the coupling between human D5 dopamine receptors and G proteins in transfected rat pituitary GH(4)C(1) cells. Similar to D1 receptors, cholera toxin treatment of cells reduced, but did not abolish, D5 agonist high-affinity binding sites, indicating D5 receptors couple to both G(x) alpha and cholera toxin-insensitive G proteins. The interaction between D5 receptors and G(s) alpha was confirmed by immunoprecipitation studies and by the ability of D5 receptors to stimulate adenylyl cyclase. Unlike D1 receptors, D5 receptors did not display any pertussis toxin-sensitive G-protein coupling to G(o) alpha or G(i) alpha. D5 receptors were also not coupled to G(q) alpha and were unable to mediate phosphatidylinositol metabolism. Instead, D5 sites appeared to be coupled to an AlF4--sensitive, N-ethylmaleimide-resistant G protein. Anti-G(z) alpha caused immunoprecipitation of 24.2 +/- 5.2% of G protein-associated D5 receptors, indicating coupling between D5 and G(z) alpha. The coupling to G(z) alpha was specific for D5 receptors, because similar associations were not detected between D1 receptors and G(z) alpha.
  • K Kimura, M Moriyama, M Nishisako, Y Kannan, M Shiota, T Sugano
    HORMONE AND METABOLIC RESEARCH 30 4 178 - 181 1998年04月 [査読無し][通常論文]
     
    Effects of endotoxin on arachidonic acid (AA)-induced hepatic glycogenolysis were examined in perfused rat liver. in normal rat liver, infusion of AA increased oxygen consumption and glucose production concurrently. in rats injected with lipopolysaccharide (LPS) 6 h before, AA increased glucose production but suppressed oxygen consumption. The changes in LPS-injected rat were abolished by a thromboxane (Tx) A(2) receptor antagonist. The release of Tx B-2 by AA increased after LPS-injection. These results suggest that priming of hepatic macrophage by endotoxin in vivo enhances Tx synthesis, resulting in modulating hepatic glycogenolysis.
  • β3-aderenergic receptor and brown adipose tissue.
    The lipid 9 253 - 258 1998年 [査読無し][通常論文]
  • Li, Y.Q, Kobayashi, M, Yuan, L, Wang, J, Matsushita, K, Hamada, J, Kimura, K, Yagita, H, Okumura, K, Hosokawa, M
    Immunology 93 4 455 - 461 1998年 [査読無し][通常論文]
  • Modulation of platelet activating factor induced glycogenolysis in the perfused rat liver after administration of endotoxin in vivo.
    Kimura, K, Moriyama, M, Nishisako, M, Kannan, Y, Shiota, M, Sakurada, K, Musashi, M, Sugano, T
    Journal of Biochemistry 123 143 - 150 1998年 [査読無し][通常論文]
  • H Kitamura, A Konno, M Morimatsu, BD Jung, K Kimura, M Saito
    BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS 238 3 707 - 711 1997年09月 [査読無し][通常論文]
     
    When mice were subjected to restriction of movement in a small cylinder (immobilization stress), the serum interleukin (IL)-6 level rose in 1 h, following increased expression of IL-6 mRNA in both the liver and the spleen. The IL-6 mRNA induction was much greater in the liver than in the spleen when compared on a whole-organ basis. Intraperitoneal injection of bacterial lipopolysaccharide (LPS) also increased IL-6 mRNA expression in these organs, but more preferentially in the spleen. Immunohistochemical examinations of liver tissue using an antibody against murine IL-6 revealed that immobilization stress induced IL-6 mainly in hepatic parenchymal cells, whereas LPS injection did so only in sinusoidal mononuclear cells. These results indicate that immobilization stress induces IL-6 production in the liver, especially in hepatic parenchymal cells, probably by a different mechanism from that for IL-6 induction by LPS. (C) 1997 Academic Press.
  • S Sela, BH White, M Uh, K Kimura, S Patel, A Sidhu
    JOURNAL OF HYPERTENSION 15 3 259 - 267 1997年03月 [査読無し][通常論文]
     
    Background Dysfunctional dopamine neurotransmission and defective D1(A) receptor-G protein coupling exist in renal proximal tubules (RPT) of the spontaneously hypertensive rat (SHR). Objective To determine whether the G proteins in SHR are abnormal, preventing formation of agonist high affinity sites in SHR, Methods We examined the expression levels of the alpha-subunits of G proteins, as well as D1(A) receptor receptor coupling to exogenously added normal G proteins, in RPT of SHR and the normotensive Wister-Kyoto (WKY) rat, Results In the presence of 110 mmol/l NaCl, the D1(A) dopamine receptor-selective agonist SKF R-38393 binds both to high- and to low-affinity sites on solubilized and reconstituted D1(A) receptors extracted from renal proximal tubules of normotensive Wistar-Kyoto (WKY) rats, In the spontaneously hypertensive rat (SHR), SKF R-38393 bound to a single site on the reconstituted receptor with affinity values corresponding to the low-affinity state of the receptor, Western blot analyses indicated that the alpha-subunit of the guanine nucleotide binding protein (G-protein), G(s), was expressed at similar levels, whereas G(o) alpha was not expressed in proximal tubule membranes from WKY rats and SHR. Pretreatment of proximal tubule membranes with the alkylating agent N-ethylmaleimide in the presence of SKF R-38393 inactivated alpha-subunits of endogenous G-proteins, but not D1(A) receptors, resulting in loss of high-affinity binding sites in WKY rats, These N-ethylmaleimide-treated D1(A) receptors from WKY rats, when reconstituted with exogenous sources of G-proteins, were able to couple to these exogenous G-proteins, with complete restoration of high-affinity sites, Moreover, the affinity values and the proportion of these hybrid sites were similar to those of untreated receptors, and these affinity sites were regulated by guanine nucleotide analogs, Reconstitution of D1(A) receptors from SHR with the same exogenous G-proteins failed to similarly induce formation of the high-affinity binding sites in the hybrid reconstituted systems, and SKF R-38393 continued to bind in a single low-affinity state of the receptor, Conclusion These results demonstrate that the absence of G-protein coupling in SHR is due to intrinsic defects within the receptor protein, rather than to any abnormalities of the endogenous G-proteins themselves.
  • Sidhu, A, Kimura, K
    Journal of Neurochemistry 68 1 187 - 194 1997年01月 [査読無し][通常論文]
     
    Exposure of human neuroblastoma SK-N-MC cells to 100 mu M dopamine (DA) for 72 h caused 70% loss of immunodetectable membrane-bound levels of the alpha-subunit of G(s). The loss in G(s) alpha was accompanied by reduced (64.3 +/- 0.35% of control values) NaF-mediated stimulation of adenylyl cyclase and was independent of accumulated cyclic AMP (cAMP) levels, because neither forskolin nor dibutyryl cAMP treatment of cells mimicked the DA-induced effects. The reduction in G(s) alpha content was manifest at the transcriptional level; G(s) alpha mRNA levels were attenuated to 56.5 +/- 10% of control values after a 24-h treatment of cells with 100 mu M DA. The concentration of DA required to produce the half-maximal decrease of G(s) alpha mRNA content was 20 nM, similar to the high-affinity binding value (8.5 nM) of DA to D1 sites. G(s) alpha mRNA levels were also attenuated (52 +/- 3.5% of control values) by the D1-selective agonist SKF R-38393 but not by forskolin or dibutyryl cAMP. Attenuation of G(s) alpha mRNA levels by agonists was blocked by the D1-selective antagonist SCH 23390. Stimulation of adenylyl cyclase-inhibitory DA receptors, which are coexpressed in these cells, failed to down-regulate G(s) alpha mRNA, indicating that regulation of G(s) alpha mRNA expression occurs specifically through chronic stimulation of D1 DA receptors.
  • K Kimura, M Hamada, M Moriyama, Y Kannan, M Shiota, K Sakurada, M Musashi, T Sugano
    JOURNAL OF BIOCHEMISTRY 120 3 488 - 493 1996年09月 [査読無し][通常論文]
     
    Mannan, a ligand for the mannose/N-acetylglucosamine (GlcNAc) receptor, induces suppression of oxygen consumption and increases glucose production in the perfused rat liver, and repeated infusion of mannan causes desensitization of the responses, In this study, we examined whether activation of Kupffer cells by endotoxin and phorbol ester alters the glycogenolytic responses to mannan, Infusion of lipopolysaccharide (LPS, 10 mu g/ml) in the perfusate failed to inhibit the responses to mannan, Intravenous administration of LPS (1 mg/kg) 6 and 24 h before perfusion did not desensitize the responses to mannan, suggesting that the responses through mannose/GlcNAc receptors in the liver ape retained even after activation of Kupffer cells by LPS, In contrast, prior infusion of phorbol 12-myristate 13-acetate (PMA, 100 nM) in vitro abolished the glycogenolytic responses to subsequently infused mannan, but not that to norepinephrine (100 nM), while prior infusions of 4-alpha-phorbol 12,13-didecanoate (100 nM), A23187 (50 nM), or forskolin (1 mu M) had no effect on the mannan-induced responses, H-7, an inhibitor of protein kinase C, reduced the glycogenolytic responses to mannan, while it failed to restore the desensitization. These results suggest that protein kinase C may be involved in the process of glycogenolysis by mannan, but is unlikely to be involved in the homologous desensitization of the responses.
  • M Moriyama, Makiyama, I, M Shiota, K Uesugi, Y Kannan, M Ohta, K Kimura, T Sugano
    HEPATOLOGY 23 6 1584 - 1590 1996年06月 [査読無し][通常論文]
     
    Ureagenesis from ammonia, alanine, and glutamine in the liver after partial hepatectomy (PH) was determined by using the liver-perfusion system, The maximum rate of ureagenesis from ammonium chloride (10 mmol/L) in hepatectomized (HX) rats at 24 hours after surgery was obtained in the presence of ornithine, lactate, and pyruvate, and it was almost identical to that in sham-operated (SO) rats, The rate of urea production hom glutamine (1 mmol/L or 10 mmol/L) in HX rats was significantly lower than that of SO rats with a concomitant decrease in hepatic glutaminase activities, However, the rate of urea synthesis from glutamine (1 mmol/L) in the presence of added ammonia (0.5 mmol/L) was accelerated approximately 10-fold, and the significant difference in the rate of urea formation between HX and SO rats was abolished, This result indicates that there is enough glutaminase to generate ammonia from glutamine in the liver of HX rats. The rate of urea production from alanine (1 mmol/L or 10 mmol/L) in HX rats was significantly decreased at 24 hours following surgery, while that of SO rats was increased. The decreased formation of urea from alanine was not seen at 72 and 120 hours after the operation, These results suggest that during the proliferation phase of liver regeneration, a reduction of ureagenesis from alanine facilitates the remnant Liver to make nonessential amino acids such as aspartate, This metabolic alteration might be related to the proliferation of Liver cells.
  • K KIMURA, Y OKAMOTO, H SASHIWA, H SAIMOTO, Y SHIGEMASA, M MORIYAMA, M SHIOTA, T SUGANO
    JOURNAL OF BIOCHEMISTRY 118 5 953 - 958 1995年11月 [査読無し][通常論文]
     
    Mannan interacts with mannose/N-acetylglucosamine (GIcNAc) receptors on the surface of both Kupffer cells and endothelial cells in the liver, and induces glycogenolysis through production of peptide-leukotriene (LT) in the perfused rat liver, In the present study, we examined whether positively and negatively charged GlcNAc-containing polysaccharides stimulate glycogenolysis in perfused rat liver, Infusion of the former, 67% deacetylated chitin (DAC), induced biphasic increases in glucose production and a steep decrease in oxygen consumption by the liver, ONO-1078, an LT D-4 receptor antagonist, abolished the suppression of oxygen consumption and reduced the glucose production by DAC, Infusion of the latter, hyaluronan, stimulated glucose production with a concomitant increase in oxygen consumption, Ibuprofen, a cyclooxygenase inhibitor, reduced the glucose production by hyaluronan, Sequential infusions of mannan and DAC, but not hyaluronan, did not induce glycogenolytic responses when mannan was infused 20 min before the second stimulation, These results suggest that DAC, but not hyaluronan, stimulates mannose/GlcNAc receptors in the perfused rat liver, and that potent immunological activity induced by DAC may be mediated by activation of the receptors.
  • K KIMURA, BH WHITE, A SIDHU
    JOURNAL OF BIOLOGICAL CHEMISTRY 270 24 14672 - 14678 1995年06月 [査読無し][通常論文]
     
    Coupling between D-1 dopamine receptors and G proteins in cell lines expressing human D-1 receptors and different G proteins was examined. Pertussis toxin (PTX) treatment of rat pituitary GH(4)C(1) cells significantly reduced, but did not abolish, agonist high affinity binding sites of the D-1 dopamine receptor; in SK-N-MC neuroblastoma cells, PTX failed to have any effect on D-1 high affinity sites. Cholera toxin (CTX) treatment of GH(4)C(1) cells reduced but did not abolish the high affinity sites of D-1 receptors, while in SK-N-MC cells, treatment with CTX abolished all the high affinity sites. Western blot analyses with specific antisera indicated that G(s) alpha, Q(i1)alpha, G(i3)alpha and G(q) alpha were expressed in both cell lines, while G(i2)alpha and G(o) alpha were expressed in GH(4)C(1) but not SK-N-MC cells. Antisera NEI-805 (anti-G(s) alpha) and 9072 (anti-G(o) alpha) immunoprecipitated 24 +/- 4.3 and 34.4 +/- 6.9%, respectively, of G protein-associated D-1 dopamine receptors. Antisera 3646 (anti-G(i1)alpha), 1521 (anti-G(i2)alpha), 1518 (anti-G(i3)alpha), and 0941 (anti-G(q) alpha) failed to coimmunoprecipitate appreciable levels df soluble receptors. These data indicate that D-1 dopamine receptors are coupled to both G(s) alpha and G(o) alpha but not to G(q) alpha.
  • K KIMURA, S SELA, C BOUVIER, DK GRANDY, A SIDHU
    JOURNAL OF NEUROCHEMISTRY 64 5 2118 - 2124 1995年05月 [査読無し][通常論文]
     
    D1 and D5 dopamine receptor genes, stably expressed in GH(4)C(1) rat somatomammotrophic cells, display identical binding values and stimulate adenylate cyclase. Approximately 60% of D1 receptors were in the agonist high-affinity state and were converted to the low-affinity slate by 100 mu M guanyl-5'-ylimidodiphosphate [Gpp(NH)p]. Of the 48% of D5 receptors in the high-affinity state, only half were modulated by 100 mu M Gpp(NH)p; in the presence of the G protein activator, AIF(4)(-), the high-affinity sites of D5 receptors were abolished by Gpp(NH)p, suggesting tight coupling between D5 receptors and G proteins. The high-affinity sites of D1, but not D5, receptors were reduced after pertussis toxin treatment of cells. Thus, whereas D1 receptors in GH(4)C(1) cells couple to both G(s), the G stimulatory protein, and a pertussis toxin-sensitive G protein, D5 receptors couple to G(s) and a pertussis toxin-insensitive G protein. Neither D1 nor D5 receptors were able to stimulate phosphoinositide metabolism in these cells. The ability of D5, but not D1, receptors to couple to novel G proteins may be significant in assigning a functional role for these receptors.
  • M SHIOTA, F CHINZEI, M MORIYAMA, K KIMURA, T SUGANO
    JOURNAL OF BIOCHEMISTRY 117 5 958 - 964 1995年05月 [査読有り][通常論文]
     
    The effects of increases in perfusion pressure and direction of perfusion flow (anterograde and retrograde) on hepatic carbohydrate metabolism were examined in the isolated perfused rat liver, Changing the direction of flow from anterograde (portal to caval vein) to retrograde (caval to portal vein) increased the rates of glycogenolysis and gluconeogenesis from sorbitol, lactate, pyruvate, and dihydroxyacetone. The extent of stimulation of gluconeogenesis by norepinephrine was higher during anterograde perfusion while stimulation by glucagon was higher during retrograde perfusion, Since the inflowing perfusion pressure was higher in retrograde perfusion (3.8 mmHg) than during anterograde perfusion (2.2 mmHg), we examined the effect of elevation in perfusion pressure on hepatic metabolism, In anterograde (portal to caval vein) perfusion, increases in perfusion pressure above the basal level (2.2 mmHg) caused increases in rates of glycogenolysis and gluconeogenesis with maximum rates at 4 mmHg, The extent of stimulation of gluconeogenesis by norepinephrine decreased and that by glucagon increased during perfusion at elevated pressure, At the same perfusion pressure (4 mmHg), there were no differences in rates of glycogenolysis and gluconeogenesis and in the responses to hormones between anterogradely and retrogradely perfused livers, The omission of Ca2+ ions from the perfusate abolished the effects of retrograde perfusion and of the elevation of perfusion pressure on carbohydrate metabolism, An infusion of A23187 (30 nM) induced an increase in both glycogenolysis and gluconeogenesis with unchanged perfusion pressure. The results suggest that elevated perfusion pressure during retrograde perfusion stimulates hepatic carbohydrate metabolism via a Ca2+-dependent process.
  • Differences in photoaffinity labeling of DA. reaptous in renal proximal tubules from normotensive rat and SHR.
    Vachvanichsanong, P, Kimura, K, Sidhu, A
    American Journal of Physiology 268 F1009 - F1016 1995年 [査読無し][通常論文]
  • Cold acclination indues zonal heterogeneity in gluconeogenic responses to glucagon in rat liver lobule.
    Shiota, M, Inagami, M, Fujimoto, Y, Moriyama, M, Kimura, K, Sugano, T
    American Journal of Physiology Endocrinology and Metabolism 268 E1184 - E1191 1995年 [査読無し][通常論文]
  • K KIMURA, M HAMADA, M MORIYAMA, M SHIOTA, M OHTA, T SUGANO
    CELLS OF THE HEPATIC SINUSOID, VOL 5 370 - 371 1995年 [査読有り][通常論文]
  • K KIMURA, A SIDHU
    JOURNAL OF NEUROCHEMISTRY 63 6 2093 - 2098 1994年12月 [査読無し][通常論文]
     
    Effects of ascorbic acid (AA) on I-125-SCH 23982 binding to D-1 dopaminergic receptors in membrane preparations from rat striatum were investigated. AA in the range of 0.03 mu M-0.33 mM inhibited 75% of specific binding of I-125-SCH 23982 in a dose-dependent manner. At higher concentrations, this inhibition of binding activity by AA was less potent, and 3.3 mM AA inhibited only 30% of specific binding. Reduced glutathione did not alter the inhibition of binding by 0.33 mM AA, but reduced the inhibition by 3.3 mM AA to 8% of specific binding. The loss of specific binding by AA was rescued by 1 mM EDTA, an inhibitor of lipid peroxidation. In the absence of AA, competition experiments with the agonist, dopamine, revealed the presence of high-affinity (K-h = 224.9 +/- 48.9 nM) and low-affinity (K-l = 21,100 +/- 2,400 nM) binding sites. Although the maximum binding of I-125-SCH 23982 decreased to 40% without affecting the K-D value in the presence of 1.67 mM AA, the value of the high-affinity site for dopamine was increased (K-h = 23.3 +/- 9.4 nM) and that of the low-affinity site was decreased (K-l = 136,800 +/- 40,900 nM). These results suggest that AA may affect D-1 dopamine receptor function by lipid peroxidation, competition with dopamine for low-affinity sites, and reduced oxidation of dopamine.
  • A SIDHU, K KIMURA, P VACHVANICHSANONG
    BIOCHEMISTRY 33 37 11246 - 11253 1994年09月 [査読有り][通常論文]
     
    We have purified the D-1 dopamine receptor 8200-fold to 78% purity from rat striatal membranes. Critical to this purification was the N-ethylmaleimide (NEM)-mediated alkylation of all endogenous sulfhydryl groups, except those associated with the D-1 dopamine receptors, which were protected by the D-1 agonist SKF R-38393. Such NEM treatment of D-1 receptors abolished all agonist high-affinity binding sites of the receptors, but did not alter the antagonist binding properties. When NEM-treated D-1 receptors were affinity-purified by mercury-agarose columns, the pharmacological properties of these purified receptors were examined, after removal of beta-mercaptoethanol (beta ME), which was used for elution of receptors from the affinity column. Purified D-1 receptors displayed typical dopaminergic antagonist binding values; however, agonists bound to the purified receptors with only high-affinity binding values, despite the prior absence of high-affinity sites in crude soluble extracts of NEM-treated receptors. The agonist high-affinity binding of purified D-1 receptors was insensitive to modulation by the GTP analog Gpp(NH)p and occurred in the absence of any G proteins. These Gpp(NH)p-insensitive high-affinity sites appeared to be induced by beta ME, since similar high-affinity binding was also restored by beta ME to crude soluble and membrane-bound receptors, which had been pretreated with NEM. The ability of D-1 dopamine receptors to bind with high-affinity to agonists in the absence of functionally active G proteins may be an intrinsic property of the reduced state of D-1 dopamine receptors.
  • A SIDHU, K KIMURA
    JOURNAL OF NEUROCHEMISTRY 63 1 201 - 206 1994年07月 [査読有り][通常論文]
     
    Solubilization of rat striatal membranes with sodium cholate, followed by reconstitution into phospholipid vesicles, leads to a 6.5-fold increase in the agonist high-affinity binding sites of the D-1 dopamine receptor. These high-affinity binding sites display differential sensitivity toward temperature. When reconstituted receptors were preincubated for 1 h at 0-4 degrees C (on ice) or at 22 degrees C (room temperature) followed by radioligand binding assays with dopamine, neither the high-affinity values of the receptor for dopamine nor the percent receptors in the high-affinity state (31-39%) were changed from control reconstituted receptors, which were not subject to any preincubations. At 30 degrees C, there was a partial loss in the number of high-affinity D-1 receptors with only 25% of the total receptor population in the high-affinity state; there was no change in the affinity values of the high-affinity binding sites. At 37 degrees C, there was a 40% loss in total number of D-1 receptor binding sites. All the high-affinity binding sites were lost and the remaining 60% of binding activity represented the low-affinity binding slate of the receptor. These results indicate that the high-affinity binding sites of the reconstituted D-1 dopamine receptors are uniquely sensitive to higher temperatures.
  • M SHIOTA, M HIRAMATSU, Y FUJIMOTO, M MORIYAMA, K KIMURA, M OHTA, T SUGANO
    ARCHIVES OF BIOCHEMISTRY AND BIOPHYSICS 308 2 349 - 356 1994年02月 [査読有り][通常論文]
     
    The capacity of the malate-aspartate shuttle was evaluated in periportal (PP-H) and perivenous subfraction of rat hepatocytes (PV-H). The rate of glutamine production from alanine was 34-fold higher in PV-H than in PP-H. Statistically significant differences between PP-H and PV-H were found for the activities of lactate dehydrogenase and pyruvate kinase but not for the activities of NAD(+)-malate dehydrogenase, aspartate aminotransferase, and mitochondrial alanine aminotransferase. The rate of glucose production from sorbitol and the rate of ethanol utilization were higher in PP-H than in PV-H. In the presence of phenazine methosulfate (PMS), the increments in these rates were significantly greater in PV-H than in PP-H. The capacity of malate-aspartate shuttle in the presence of alanine was significantly higher in PP-H than in PV-H but in the presence of asparagine was similar in PP-H and PV-H. The results suggest that the capacity of malate-aspartate shuttle distributes heterogeneously along liver lobules with the dominance in periportal zone and that the difference of the capacity may result from the difference in the transport of aspartate across the mitochondrial membrane. (C) 1994 Academic Press, Inc.
  • P BALEN, K KIMURA, A SIDHU
    BIOCHEMISTRY 33 6 1539 - 1544 1994年02月 [査読有り][通常論文]
     
    We have reported the solubilization and reconstitution of functional D-1 dopamine receptors from rat striatal tissue, using sodium cholate as detergent [Sidhu, A. (1988) Biochemistry 27, 8768-8776]. Critical to our method of extraction was the absolute requirement for the persistent presence of a crude extract of phospholipids (PLs) from bovine brain, during both solubilization of membranes and reconstitution of the soluble extract into PL vesicles. In the absence of PLs, fewer than 10% of the receptors were recovered, while in the presence of PLs, 40% of the receptors were reconstituted into vesicles. To probe the composition of PLs required by D-1 dopamine receptors during these extraction procedures, specific PLs of a defined composition were used during either solubilization or reconstitution alone or during both solubilization and reconstitution. Phosphatidylcholine (PC), when used during the solublization procedure alone or during both solubilization and reconstitution, resulted in recovery of 41-48% of the D-1 dopamine receptors but was 3.7-fold less effective when present during reconstitution alone (11%). Phosphatidylethanolamine (PE), when used during reconstitution alone, resulted in recovery of nearly 25% of the D-1 dopamine receptors. When PE was present during either solubilization or both solubilization and reconstitution, 6-11% of the receptors were recovered. If PE was used with PC in ratios of 1:1 or 2:1, respectively, 28-38% of the receptors were recovered. When PL vesicles of PE:PC were present in ratios of 1:2 during both solubilization and reconstitution, the maximum theoretical (74-87%) recovery of total receptor binding sites was achieved. These reconstituted receptors were pharmacologically active, with 53.5% of the receptor population present in the high-affinity state.
  • Adaptive changes in zonation for gluconeogenic capacity in liver lobules of cold-exposed rats
    Shiota, M, Fujimoto, Y, Inagami, M, Hiramatsu, M, Moriyama, M, Kimura, K, Ohta, M, Sugano, T
    American Journal of Physiology 265 E559 - E564 1993年 [査読無し][通常論文]
  • Responses to catecholamines in perfused livers of hypothalamic lesioned rats.
    Matsui, Y, Ishibashi, H, Kimura, K, Shiota, M, Ohta, M, Sugano, T
    American Journal of Physiology 265 R117 - R123 1993年 [査読有り][通常論文]
  • M SHIOTA, Y KURANO, Y MOCHIZUKI, K KIMURA, M OHTA, T SUGANO
    AMERICAN JOURNAL OF PHYSIOLOGY 263 3 G353 - G359 1992年09月 [査読有り][通常論文]
     
    The effects of sympathetic nerve stimulation and zymosan (cell wall particles from yeast) on glycogenolysis were studied in perfused livers from rats kept for 5 and 20 days at 4-degrees-C. The rate of glycogenolysis induced by nerve stimulation decreased significantly without any decrease in norepinephrine outflow during cold exposure, and the rate induced by norepinephrine did not change. By contrast, the rate of zymosan-induced glycogenolysis increased markedly during cold exposure. The rats with denervated hepatic nerves did not show the increased response to zymosan. In cold-exposed rats, both mepacrine and ibuprofen inhibited the effects of zymosan and of nerve stimulation without any inhibition of the outflow of norepinephrine. Neither inhibitor had any effect on the effects of norepinephrine. The metabolic effects of nerve stimulation and zymosan were not additive in cold-exposed rats. These results suggest that cold exposure may modulate the metabolism of arachidonic acid in Kupffer cells via hepatic nerve and decrease the eicosanoid-dependent glycogenolysis by nerve stimulation.
  • K KIMURA, M SHIOTA, K MOCHIZUKI, M OHTA, T SUGANO
    BIOCHEMICAL JOURNAL 283 773 - 779 1992年05月 [査読無し][通常論文]
     
    Zymosan (non-boiled) induced glycogenolysis biphasically, with no lag time, in the perfused rat liver. After the zymosan was boiled, it could be separated into two fractions, both of which stimulated glycogenolysis independently. The soluble fraction of boiled zymosan (zymosan sup) showed homologous desensitization, indicating that zymosan sup-induced glycogenolysis is a receptor-mediated event. Mannan (polymannose), which is known to be a biologically active component of zymosan, induced a glycogenolytic response similar to that produced by zymosan sup, and desensitized the response to the latter. Preinfusion of platelet-activating factor (PAF, 20 nM) or isoprenaline (10-mu-M) did not extinguish the glycogenolytic response to zymosan sup, while the response to a secondary infusion of PAF was blocked. The glycogenolytic response to zymosan sup was completely inhibited by nordihydroguaiaretic acid (NDGA, 10-mu-M), a lipoxygenase inhibitor, and by ONO- 1078 (100 ng/ml), a leukotriene (LT) D4 receptor antagonist. On the other hand, the glycogenolytic effect of zymosan pellet (the particulate fraction of boiled zymosan) was not affected by preinfusion of zymosan sup, and was inhibited by ibuprofen (20-mu-M), a cyclo-oxygenase inhibitor. Prostaglandins (PGs) detected in the perfusate were augmented with infusion of zymosan pellet. Opsonization of the zymosan pellet by serum (complement) enhanced the glycogenolytic response without a lag period, and with a concomitant enhancement of PG output. Correlations between glucose production and PGs were r = 0.832 (PGD2), r = 0.872 (PGF2-alpha), r = 0.752 (PGE2) and r = 0.349 (6-oxo-PGF1-alpha). The glycogenolytic response to non-boiled zymosan was delayed and the biphasic glycogenolytic response was not observed when mannan was infused first. NDGA mimicked the effects of the preinfusion of mannan, while ibuprofen had no effect on the non-boiled-zymosan-induced glycogenolysis. These results suggest: (1) that non-boiled zymosan stimulates glycogenolysis through a mannose receptor-dependent, but unidentified, pathway, (2) that zymosan sup induces glycogenolysis via mannose receptor activation through the production of peptide-LTs but not PAF, and (3) that zymosan pellet causes glycogenolysis through the production of prostanoids, which is enhanced in the presence of complement.
  • K KIMURA, H MATSUBARA, S SOGOH, Y KITA, T SAKATA, Y NISHITANI, S WATANABE, T HAMAOKA, H FUJIWARA
    JOURNAL OF IMMUNOLOGY 146 8 2618 - 2624 1991年04月 [査読無し][通常論文]
     
    The present study investigates the regulatory effects of glycosaminoglycans such as heparin and heparan sulfate on T cell proliferation induced by thymic stromal cell monolayer or its derived T cell growth factor (TCGF). A thymic stromal cell clone (MRL104.8a) supported the growth of Ag-specific, IL-2-dependent Th cell clone (9-16) in the absence of Ag and IL-2 by producing a unique TCGF designated as thymic stroma-derived T cell growth factor (TSTGF). The addition of heparin to cultures in which the growth of 9-16 Th cells was otherwise stimulated by the MRL104.8a monolayer or a semipurified sample of the TSTGF resulted in heparin dose-dependent inhibition of 9-16 Th proliferation. The dose of heparin required for inducing 50% reduction of TSTGF-induced proliferation of Th at a given cell number was found to be proportional to the magnitude of the TSTGF added to cultures, suggesting that heparin exerted its inhibitory effect by binding to the TSTGF rather than by acting on Th cells. A similar growth-inhibiting effect of heparin was observed in IL-7-dependent proliferation of pre-B cell line or Th, but not in IL-2-dependent T cell proliferation or IL-3-dependent myeloid cell proliferation. A strong affinity of TSTGF and IL-7 for heparin was confirmed by the fact that both TSTGF and IL-7 adhered to columns of heparin-agarose and were eluted by salt. When various glycosaminoglycans were tested for the heparin-like Th growth-regulatory capacity, heparan sulfate exhibited Th growth-inhibiting ability comparable to that observed for heparin. These results indicate that the activity of thymic and/or bone marrow stroma-derived lymphocyte growth factor (TSTGF/IL-7) but not of Th-producing TCGF (IL-2) is negatively regulated by heparin or heparan sulfate, which would represent major glycosaminoglycans in the extracellular matrix of stromal cells.
  • Effects of calmodulin antagonists on hydrogen-translocating shuttles in perfused rat liver.
    Hamatani, Y, Inoue, M, Kimura, K, Shiota, M, Ohta, M, Sugano, T
    American Journal of Physiology 261 E325 - E331 1991年 [査読有り][通常論文]
  • Y TATSUMI, A KUMANOGOH, M SAITOH, Y MIZUSHIMA, K KIMURA, S SUZUKI, H YAGI, A HORIUCHI, M OGATA, T HAMAOKA, H FUJIWARA
    PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA 87 7 2750 - 2754 1990年04月 [査読有り][通常論文]
  • T SUDA, J SHIMIZU, M MURAMATSU, K KIMURA, TO YOSHIDA, Y FUKAMI, H FUJIWARA, T HAMAOKA
    JAPANESE JOURNAL OF CANCER RESEARCH 80 9 879 - 886 1989年09月 [査読有り][通常論文]
  • N KATOH, K KIMURA
    AMERICAN JOURNAL OF VETERINARY RESEARCH 50 9 1489 - 1492 1989年09月 [査読有り][通常論文]
  • Katoh, N, Kimura, K
    Japanese Journal of Veterinary Science (J. Vet. Med. Sci.) 51 105 - 109 1988年 [査読有り][通常論文]
  • K KIMURA, S KUBO, K SAKURADA, K ABE, N KATOH
    BIOCHIMICA ET BIOPHYSICA ACTA 929 2 203 - 207 1987年07月 [査読有り][通常論文]
  • K SAKURADA, T MIYAZAKI, K KIMURA, M YAMABE, F KATABAMI, M KOYAMA, Y UEHARA, N KATOH
    CANCER RESEARCH 45 2 903 - 908 1985年 [査読有り][通常論文]
  • N KATOH, K KIMURA, K SAKURADA
    JOURNAL OF BIOCHEMISTRY 97 3 859 - 866 1985年 [査読有り][通常論文]
  • K KIMURA, K SAKURADA, N KATOH
    BIOCHIMICA ET BIOPHYSICA ACTA 839 3 276 - 280 1985年 [査読有り][通常論文]
  • K KIMURA, N KATOH, K SAKURADA, S KUBO
    BIOCHEMICAL JOURNAL 227 1 271 - 276 1985年 [査読有り][通常論文]
  • K KIMURA, N KATOH, K SAKURADA, S KUBO
    ENDOCRINOLOGY 115 6 2391 - 2399 1984年 [査読無し][通常論文]

書籍

  • Patel VB ed. Molecular Nutrition: Carbohydrate
    松岡慎也, 木村和弘他 (担当:分担執筆範囲:Linking pathways and processes: retinoic acid and glucose. Chapter 15, pp247-264)
    Academic press, Elsevier 2019年
  • 改訂. 獣医生化学
    木村 和弘 (担当:編者(編著者)範囲:編集および第14章細胞間情報伝達と受容、応答、調節 pp147-168の執筆)
    朝倉書店 2016年04月
  • Conceptual background and bioenergetic/mitochondrial aspects of oncometabolism. in Methods of Enzymology
    木村 和弘 (担当:分担執筆範囲:Measurement of enolase activity in cell lysates.Methods Enzymol 542, 115-124.)
    Elsever 2014年
  • 特集 褐色脂肪細胞と食品成分−抗肥満へのアプローチ
    木村 和弘 (担当:監修範囲:特集号の監修 30巻11号)
    バイオインダストリー 2013年11月
  • Sima AAF (ed) Diabetes and C-Peptide: Scientific and Clinical Aspects. Contemporary Diabetes
    木村 和弘 (担当:分担執筆範囲:Is NO-eNOS a target for C-peptide action and its protective effects on diabetic nephropathy? (Chapter6))
    Springer Science+Business Media, LLC 2011年
  • からだと酸素の辞典 (酸素ダイナミックス研究会編)
    木村 和弘 (担当:分担執筆範囲:UCPと酸素消費量)
    朝倉書店 2009年
  • 獣医生化学実験
    獣医生理学, 生理化学教育懇談会 (担当:監修範囲:第3版改訂監修)
    緑書房 2008年04月
  • ホルモンハンドブック 新訂eBook版(日本比較内分泌学会編)
    木村 和弘 (担当:分担執筆範囲:レプチン (Section I-E-4-g))
    南江堂 2007年
  • 獣医生化学
    木村 和弘 (担当:分担執筆範囲:細胞間情報伝達と受容、応答、調節(第15章))
    朝倉書店 2005年
  • 臓器灌流実験講座 (臓器灌流研究会編)
    木村 和弘 (担当:分担執筆範囲:プロスタノイドの生成とグリコーゲン分解)
    新興医学出版 2000年
  • Prostanoid synthesis and glycogenolysis in the perfused liver.
    2000年
  • Cells of the hepatic sinusoid. Vol.V (Wisse, E., Knook, D.L., and Wake, K. eds)
    KIMURA Kazuhiro (担当:分担執筆範囲:Phorbol ester altered phagocytosis-induced glycogenolysis by activating thromboxane production in perfused rat liver.)
    The Kupffer Cell Foundation, Leiden, The Netherlands 1995年
  • Phorbol ester altered phagocytosis-indused glycogenolysis by activating thromboxane production in perfused rat liver
    Cell of the hepatic sinusoid 1995年

その他活動・業績

特許

受賞

  • 2006年03月 日本獣医学会賞
     
    受賞者: 木村 和弘

共同研究・競争的資金等の研究課題

  • 文部科学省:科学研究費補助金(基盤研究(B))
    研究期間 : 2009年 -2011年 
    代表者 : 木村 和弘, 岡松 優子
     
    これまで脂肪細胞の状態が大きく異なる食餌性肥満(HFD)マウスと対照(ND)マウスを用い、HFD群未妊娠の乳腺では導管の分枝頻度が低下し、その細胞組成や間質構造にも異常があること、HFD群妊娠期乳腺においても腺房構造形成遅延と機能成熟の遅れがあることを明らかにした。ここでは出産後の泌乳期における肥満影響の解明を試みたが,HFD群のマウスでは母性行動異常により授乳がほとんどの個体でみられず、ND群との乳腺構造の単純な比較は意味がないと思われた。そこで、肥満と母性行動の関連ついて定量的解析を試みた。HFD群、ND群両間で妊娠率、胎児数に差はなかったが、肥満群では全ての胎児を娩出できた個体は35%と対照群(85%)の半数以下であった。また対照群では妊娠中の巣作り行動が80%の個体で観察されたのに対し、肥満群では70%の個体は巣作りをしなかった。さらに、出産後の育児(仔マウスを集合させるか否か)についても対照群では90%の個体で観察されたのに対し、肥満群ではわずか15%の個体のみであった。この時,血中のグルコース、遊離脂肪酸、プロラクチン、プロゲステロン、エストロゲン濃度に両群で差はなかったが、レプチン濃度に大きな差が認められた。つまり食餌性肥満は母性行動に大きく影響し、妊娠期に見られる巣作り行動や出産後の育児行動を抑制することが明らかとなった。レプチンの作用は主に脳視床下部弓状核を...
  • 文部科学省:科学研究費補助金(基盤研究(B))
    研究期間 : 2006年 -2008年 
    代表者 : 木村 和弘
     
    未妊娠の雌マウスにおいて肥満が乳腺発達異常(導管径の短縮と分岐数の減少、筋上皮細胞層の欠失とコラーゲン層の肥厚)をもたらすことを明らかにし、その異常の一部は脂肪細胞分泌因子レプチンに因ることを強く示唆した。一方、イヌ乳腺腫瘍組織より得た不死化細胞5株の増殖はレプチンにより影響されず、癌化に伴う応答性の変化が示唆された。さらに導管形成を促進する成長因子HGFの脂肪細胞における発現調節機構などについて検討した。
  • 文部科学省:科学研究費補助金(特定領域研究)
    研究期間 : 2003年 -2007年 
    代表者 : 斉藤 昌之, 木村 和弘
     
    哺乳動物には通常の白色脂肪とは別に褐色脂肪組織(BAT)があり、ミトコンドリアにある脱共役蛋白質(UCP1)の働きによって熱を産生している。本研究では、BATについて、特に交感神経の調節作用と脂肪・糖代謝、肥満との関係に焦点を当ててマウスやイヌ、ヒトで検討した。1、β3アドレナリン受容体(AR)は脂肪細胞に局在している。正常マウスにβ3AR作動薬を投与すると、摂食量は変わらないが、BAT熱産生亢進、白色脂肪からの脂肪動員、エネルギー(酸素)消費亢進が起こり、最終的には白色脂肪細胞サイズが小さくなり体脂肪が減少した。しかし、これらの効果はUCP1欠損マウスでは見られなかった。2、同様のβ3AR作動薬の抗肥満効果がイヌでも見られることを、CTによる体脂肪量評価や血中アディポサイトカイン動態、UCP1発現などから証明した。3、主な生理的摂食抑制因子であるレプチンのエネルギー消費に対する作用についても、アデノウィルス発現法などを用いて検討した所、レプチンが白色脂肪UCP1を誘導してエネルギー消費を増やし、体脂肪減少に寄与することを見出した。これらの結果から、UCP1によるBAT熱産生がエネルギー出納の調節に重要であり、この障害が肥満の一因になると結論した。4、寒冷暴露やβAR刺激によるBAT熱産生時にはこの組織で糖代謝も亢進する。その機構をUCP1欠損マウスを用いて検討した所、βAR...
  • 文部科学省:科学研究費補助金(基盤研究(C))
    研究期間 : 2003年 -2004年 
    代表者 : 木村 和弘
     
    脱共役タンパク質(UCP)はミトコンドリア内膜と外膜間に形成されたプロトン勾配とATP合成を脱共役させる。AMP-activated protein kinase (AMPK)はATPの分解産物であるAMPによって活性化される蛋白質リン酸化酵素であり、細胞内エネルギーレベルの低下を感知して活性が上昇する。本研究ではUCPの発現あるいは活性化が細胞のATPレベルを低下させ、AMPKを介して細胞のエネルギー代謝を調節するか明らかにすることを目的とした。まずUCP1遺伝子ノックアウト(KO)マウスと野生型(WT)マウスを用いて組織へのエネルギー基質(糖)の取り込みについて調べた。インスリンを投与するといずれのマウスも褐色脂肪組織(BAT)における糖(2-DG)取り込みが亢進した。一方、ノルエピネフリン(NE)を投与するとWTのBATでは2-DG取り込みが亢進したが、KOでは変化しなかった。NE刺激によりWTではBAT組織内のAMP/ATP比が上昇し、AMPKの活性およびそのリン酸化レベルが亢進した。しかしながら、KOではAMP/ATP比、AMPK活性やリン酸化は変化しなかった。つまりBATにおいてはNEがβ3アドレナリン受容体を介してUCP1を活性化し、ATP産生を低下させることでAMPK活性を増大させ、糖の取り込みを促進すると考えられた。またUCP1がこの代謝機能の調節に必須の分...
  • 文部科学省:科学研究費補助金(基盤研究(C))
    研究期間 : 2000年 -2001年 
    代表者 : 木村 和弘
     
    脱共役タンパク質UCP2(uncoupling protein2)の肝臓での発現がエネルギー代謝調節および物質(糖・アミノ酸・脂肪酸)代謝に与える影響を明らかにするため、以下の実験を行った。肝細胞でのUCP2の発現を解析したところ、肝部分切除後の再生肝において発現が増大した。肝臓潅流法を用いて、種々の代謝について検討したところ、再生肝では脂肪酸からの酸素消費(ベータ酸化)やケトン体生成が促進し、ケトン体生成1モル当りの酸素消費量は対照に比べ有意に高く、逆にミトコンドリア内のNADH/NAD比(β-ヒドロキシ酪酸/アセト酢酸比)は有意に抑制されていた。しかしながら、UCP2の発現は偽手術群でも見られたことから、UCP2は脂肪酸化、レドックス調節、ケトン体生成とは直接関与しないと考えられた。次に、肝細胞におけるUCP2遺伝子の発現調節機構を明らかにするためにUCP2遺伝子のプロモーター領域をクローニングし、2つの肝細胞由来細胞を用いて分泌型アルカリフォスファターゼをレポーターとするレポータージーンアッセイを行った。内在性にUCP2を発現するHepG2細胞では転写関始点とその上流100塩基の間に転写調節部位が少なくとも2つ存在することが明かとなった.UCP2を発現しないHep3B細胞を用いて同様の検討を行ったところ、HepG2細胞よりもむしろ強いプロモーター活性を示した.Hep3B...
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  • Metabolic regulations in healthy and diseased animals

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