Mizutani Tatsuaki
| Faculty of Medicine Physiological Science Physiology | Lecturer |
Last Updated :2025/06/10
■Researcher basic information
Researchmap personal page
J-Global ID
Research Field
Educational Organization
- Bachelor's degree program, Departments of Medicine, School of Medicine
- Master's degree program, Graduate School of Medicine
- Doctoral (PhD) degree program, Graduate School of Medicine
■Career
Career
- Dec. 2023 - Present
Hokkaido University, Departmen of Cell Physiology Faculty of Medicine, Senior lecturer, Japan - Apr. 2022 - Nov. 2023
Institute for Life and Medical Sciences, Kyoto University., Lab of Cell Regulation, Assistant Professor, Japan - Jan. 2017 - Mar. 2022
Institute for Frontier Life and Medical Sciences Kyoto University, 細胞制御分野, Assistant professor, Japan - Jul. 2014 - Dec. 2016
Institute for virus research Kyoto university, 細胞制御分野, Assistant professor, Japan - Feb. 2013 - Jun. 2014
Nagasaki University, 創薬教育研究センター, Assistant professor, Japan - May 2010 - Feb. 2013
Ludwig-Boltzmann Institute for Cancer Research, Post-doc, Austria - Apr. 2007 - May 2010
Hokkaido University, Graduate School of Medicine, ポスドク研究員, Japan
Educational Background
- Apr. 2003 - Mar. 2007, The University of Tokyo, Graduate School of Medicine, 病因・病理学専攻, Japan
- Apr. 2001 - Mar. 2003, The University of Tokyo, Graduate School of Science, Department of Biophysics and Biochemistry, Japan
- Apr. 1996 - Mar. 2001, Tokyo Institute of Technology, School of Bioscience and Biotechnology, 生体機構学科, Japan
■Research activity information
Papers
- Neutrophil S100A9 supports M2 macrophage niche formation in granulomas
Tatsuaki Mizutani, Toshiaki Ano, Yuya Yoshioka, Satoshi Mizuta, Keiko Takemoto, Yuki Ouchi, Daisuke Morita, Satsuki Kitano, Hitoshi Miyachi, Tatsuaki Tsuruyama, Nagatoshi Fujiwara, Masahiko Sugita
iScience, 106081, 106081, Elsevier BV, Jan. 2023, [Lead author, Corresponding author]
Scientific journal - Crystal structures of N-myristoylated lipopeptide-bound HLA class I complexes indicate reorganization of B-pocket architecture upon ligand binding
Minori Asa, Daisuke Morita, Jin Kuroha, Tatsuaki Mizutani, Naoki Mori, Bunzo Mikami, Masahiko Sugita
Journal of Biological Chemistry, 298, 7, 102100, 102100, Elsevier BV, Jul. 2022
Scientific journal - Identification of novel chemical compounds targeting filovirus VP40-mediated particle production
Shuzo Urata, Olaposi Idowu Omotuyi, Ayako Izumisawa, Takeshi Ishikawa, Satoshi Mizuta, Yasuteru Sakurai, Tatsuaki Mizutani, Hiroshi Ueda, Yoshimasa Tanaka, Jiro Yasuda
Antiviral Research, 199, 105267, 105267, Elsevier BV, Feb. 2022
Scientific journal - Crystal structure of the ternary complex of TCR, MHC class I, and lipopeptides.
Daisuke Morita, Chieri Iwashita, Tatsuaki Mizutani, Naoki Mori, Bunzo Mikami, Masahiko Sugita
International immunology, 32, 12, 805, 810, 28 Jul. 2020, [Peer-reviewed], [International Magazine]
English, Scientific journal, The covalent conjugation of a 14-carbon fatty acid (myristic acid) to the N-terminal Gly residue, termed N-myristoylation, occurs in some viral proteins to dictate their pathological function. This protein lipidation reaction, however, is monitored by host cytotoxic T-lymphocytes that are capable of recognizing N-terminal lipopeptide fragments in the context of MHC class I molecules. In a rhesus model of human AIDS, for example, the classical MHC class I allomorph, Mamu-B*05104, was shown to bind SIV Nef-derived 4-mer lipopeptides (Myristic acid-Gly-Gly-Ala-Ile; C14nef4) and present them to the CD8+ T cell line, SN45. These lipopeptides accommodated in MHC class I molecules expose much shorter peptide chains than conventional MHC class I-presented 8-10-mer peptides, and the molecular mechanisms by which αβ TCRs recognize lipopeptides currently remain unclear. An X-ray crystallographic analysis of the SN45 TCR α and β heterodimer in a form that was co-crystallized with the C14nef4-bound Mamu-B*05104 complex indicated that the amide group of the N-myristoylated glycine residue offered a primary T-cell epitope by establishing a sole hydrogen bond between its nitrogen atom and the side chain of Glu at position 101 of CDR3β. Accordingly, the Glu to Ala mutation at this position resulted in the loss of lipopeptide recognition. On the other hand, TCRs were positioned remotely from the peptide portion of C14nef4, and strong interactions were not observed. Thus, these observations provide novel structural insights into lipopeptide recognition by TCRs, which contrast sharply with the general molecular principle of peptide recognition. - Crystal structures of lysophospholipid-bound MHC class I molecules.
Yoko Shima, Daisuke Morita, Tatsuaki Mizutani, Naoki Mori, Bunzo Mikami, Masahiko Sugita
The Journal of biological chemistry, 295, 20, 6983, 6991, 08 Apr. 2020, [Peer-reviewed], [International Magazine]
English, Scientific journal, Newly synthesized major histocompatibility complex (MHC) class I proteins are stabilized in the endoplasmic reticulum (ER) by binding 8- to 10-mer-long self-peptide antigens that are provided by transporter associated with antigen processing (TAP). These MHC class I:peptide complexes then exit the ER and reach the plasma membrane, serving to sustain the steady state MHC class I expression on the cell surface. A novel subset of MHC class I molecules that preferentially bind lipid-containing ligands rather than conventional peptides was recently identified. The primate classical MHC class I allomorphs, Mamu-B*098 and Mamu-B*05104, are capable of binding the N-myristoylated 5-mer (C14-Gly-Gly-Ala-Ile-Ser) or 4-mer (C14-Gly-Gly-Ala-Ile) lipopeptides derived from the N-myristoylated SIV Nef protein, respectively, and of activating lipopeptide antigen-specific cytotoxic T lymphocytes. We herein demonstrate that Mamu-B*098 samples lysophosphatidylethanolamine and lysophosphatidylcholine containing up to a C20 fatty acid in the ER. The X-ray crystal structures of Mamu-B*098 and Mamu-B*05104 complexed with lysophospholipids at high resolution revealed that the B and D pockets in the antigen-binding grooves of these MHC class I molecules accommodate these lipids through a mono-acyl glycerol moiety. Consistent with the capacity to bind cellular lipid ligands, these two MHC class I molecules did not require TAP function for cell-surface expression. Collectively, these results indicate that peptide- and lipopeptide-presenting MHC class I subsets use distinct sources of endogenous ligands. - An antiviral drug screening platform with a FRET biosensor for measurement of arenavirus Z assembly
Tatsuaki Mizutani, Yusuke Ohba, Satoshi Mizuta, Jiro Yasuda, Shuzo Urata
Cell Structure and Function, 45, 2, 155, 163, Japan Society for Cell Biology, 2020, [Peer-reviewed], [Lead author, Corresponding author], [Domestic magazines]
English, Scientific journal, The smallest arenavirus gene product, Z protein, plays critical roles in the virus life cycle. Z is the major driving force of budding and particle production because of a unique property that defines self-assembly. In addition to the roles in budding, Z also participates in the suppression of type I interferon production to evade host antiviral immunity. Therefore, Z and its assembled form are an attractive drug target for arenaviral hemorrhagic fever, such as Lassa fever. Here, we developed a biosensor that enabled the evaluation of the prototype arenavirus, lymphocytic choriomeningitis virus (LCMV), Z assembly using the principle of Förster resonance energy transfer (FRET). This FRET biosensor consisted of three tandem Z that were sandwiched between super-enhanced cyan-emitting fluorescent protein and variant of a yellow-emitting mutant of green fluorescent protein so that Z-Z intermolecular binding via the really interesting new gene finger domain increased the emission ratio. To identify novel anti-arenavirus compounds, the FRET biosensor was employed to screen the PathogenBox400 for inhibitors of Z assembly in a 96-well plate format. The assay performed well, with a Z'-factor of 0.89, and identified two compounds that decreased the emission ratio of the FRET biosensor in a dose-dependent manner. Of them, the compound, 5,6,7,8-tetrahydro-7-(benzyl)-pyrido[4',3':4,5]thieno[2,3-d]pyrimidin-2,4-diamine, was found to significantly inhibit LCMV propagation in infected cells. Thereby, the present study demonstrated that a novel FRET biosensor incorporating Z assembly built on FRET and named Zabton, was a valuable screening tool to identify anti-arenavirus compounds in the context of inhibition of Z assembly.Key words: Arenavirus, Förster resonance energy transfer, anti-viral drugs, Z protein. - STAT3β is a tumor suppressor in acute myeloid leukemia.
Petra Aigner, Tatsuaki Mizutani, Jaqueline Horvath, Thomas Eder, Stefan Heber, Karin Lind, Valentin Just, Herwig P Moll, Assa Yeroslaviz, Michael J M Fischer, Lukas Kenner, Balázs Győrffy, Heinz Sill, Florian Grebien, Richard Moriggl, Emilio Casanova, Dagmar Stoiber
Blood advances, 3, 13, 1989, 2002, 09 Jul. 2019, [Peer-reviewed], [International Magazine]
English, Signal transducer and activator of transcription 3 (STAT3) exists in 2 alternatively spliced isoforms, STAT3α and STAT3β. Although truncated STAT3β was originally postulated to act as a dominant-negative form of STAT3α, it has been shown to have various STAT3α-independent regulatory functions. Recently, STAT3β gained attention as a powerful antitumorigenic molecule in cancer. Deregulated STAT3 signaling is often found in acute myeloid leukemia (AML); however, the role of STAT3β in AML remains elusive. Therefore, we analyzed the STAT3β/α messenger RNA (mRNA) expression ratio in AML patients, where we observed that a higher STAT3β/α mRNA ratio correlated with a favorable prognosis and increased overall survival. To gain better understanding of the function of STAT3β in AML, we engineered a transgenic mouse allowing for balanced Stat3β expression. Transgenic Stat3β expression resulted in decelerated disease progression and extended survival in PTEN- and MLL-AF9-dependent AML mouse models. Our findings further suggest that the antitumorigenic function of STAT3β depends on the tumor-intrinsic regulation of a small set of significantly up- and downregulated genes, identified via RNA sequencing. In conclusion, we demonstrate that STAT3β plays an essential tumor-suppressive role in AML. - Identification and Structure of an MHC Class I-Encoded Protein with the Potential to Present N-Myristoylated 4-mer Peptides to T Cells.
Yukie Yamamoto, Daisuke Morita, Yoko Shima, Akihiro Midorikawa, Tatsuaki Mizutani, Juri Suzuki, Naoki Mori, Takashi Shiina, Hidetoshi Inoko, Yoshimasa Tanaka, Bunzo Mikami, Masahiko Sugita
Journal of immunology (Baltimore, Md. : 1950), 202, 12, 3349, 3358, 15 Jun. 2019, [Peer-reviewed], [International Magazine]
English, Scientific journal, Similar to host proteins, N-myristoylation occurs for viral proteins to dictate their pathological function. However, this lipid-modifying reaction creates a novel class of "lipopeptide" Ags targeted by host CTLs. The primate MHC class I-encoded protein, Mamu-B*098, was previously shown to bind N-myristoylated 5-mer peptides. Nevertheless, T cells exist that recognize even shorter lipopeptides, and much remains to be elucidated concerning the molecular mechanisms of lipopeptide presentation. We, in this study, demonstrate that the MHC class I allele, Mamu-B*05104, binds the N-myristoylated 4-mer peptide (C14-Gly-Gly-Ala-Ile) derived from the viral Nef protein for its presentation to CTLs. A phylogenetic tree analysis indicates that these classical MHC class I alleles are not closely associated; however, the high-resolution x-ray crystallographic analyses indicate that both molecules share lipid-binding structures defined by the exceptionally large, hydrophobic B pocket to accommodate the acylated glycine (G1) as an anchor. The C-terminal isoleucine (I4) of C14-Gly-Gly-Ala-Ile anchors at the F pocket, which is distinct from that of Mamu-B*098 and is virtually identical to that of the peptide-presenting MHC class I molecule, HLA-B51. The two central amino acid residues (G2 and A3) are only exposed externally for recognition by T cells, and the methyl side chain on A3 constitutes a major T cell epitope, underscoring that the epitopic diversity is highly limited for lipopeptides as compared with that for MHC class I-presented long peptides. These structural features suggest that lipopeptide-presenting MHC class I alleles comprise a distinct MHC class I subset that mediates an alternative pathway for CTL activation. - Neutrophils and the S100A9 protein critically regulate granuloma formation.
Yuya Yoshioka, Tatsuaki Mizutani, Satoshi Mizuta, Ayumi Miyamoto, Satoru Murata, Toshiaki Ano, Hiroshi Ichise, Daisuke Morita, Hiroyuki Yamada, Yoshihiko Hoshino, Tatsuaki Tsuruyama, Masahiko Sugita
Blood advances, 1, 3, 184, 192, 27 Dec. 2016, [Peer-reviewed], [Corresponding author], [International Magazine]
English, Scientific journal, Macrophages have the potential to undergo cellular transformation into epithelioid cells, and their concentric accumulation in tissues results in the development of granulomas. Although epithelioid cells are an essential and dominant component of granulomas, other cell types have also been detected, which may contribute to the establishment of well-organized granulomas, as observed in human granulomatous diseases. We herein demonstrated that neutrophils may mediate these functions. By taking advantage of the guinea pig pulmonary granuloma model, we obtained a rat monoclonal antibody with unique reactivity to granuloma cells. This antibody, termed G213, reacted with clusters of neutrophils located in the central area of granulomas, and a biochemical analysis identified the G213-reactive antigen as S100A9, a calcium-binding protein of the S100 family, which was expressed abundantly in neutrophils. Consistent with the multifaceted functions attributed to S100A9, including its role in neutrophil extravasation and macrophage activation, the blockade of S100A9 functions with the specific inhibitor, tasquinimod, impaired the formation of organized granulomas with neutrophil cores. These results demonstrate the critical role of neutrophils and the S100A9 protein in granuloma formation. Because intragranuloma S100A9+ neutrophils were also detected in humans, these results indicate the potential of tasquinimod, a new anticancer drug candidate, for manipulating human granulomatous diseases. - Crystal structure of the N-myristoylated lipopeptide-bound MHC class I complex.
Daisuke Morita, Yukie Yamamoto, Tatsuaki Mizutani, Takeshi Ishikawa, Juri Suzuki, Tatsuhiko Igarashi, Naoki Mori, Takashi Shiina, Hidetoshi Inoko, Hiroaki Fujita, Kazuhiro Iwai, Yoshimasa Tanaka, Bunzo Mikami, Masahiko Sugita
Nature communications, 7, 10356, 10356, 13 Jan. 2016, [Peer-reviewed], [International Magazine]
English, Scientific journal, The covalent conjugation of a 14-carbon saturated fatty acid (myristic acid) to the amino-terminal glycine residue is critical for some viral proteins to function. This protein lipidation modification, termed N-myristoylation, is targeted by host cytotoxic T lymphocytes (CTLs) that specifically recognize N-myristoylated short peptides; however, the molecular mechanisms underlying lipopeptide antigen (Ag) presentation remain elusive. Here we show that a primate major histocompatibility complex (MHC) class I-encoded protein is capable of binding N-myristoylated 5-mer peptides and presenting them to specific CTLs. A high-resolution X-ray crystallographic analysis of the MHC class I:lipopeptide complex reveals an Ag-binding groove that is elaborately constructed to bind N-myristoylated short peptides rather than prototypic 9-mer peptides. The identification of lipopeptide-specific, MHC class I-restricted CTLs indicates that the widely accepted concept of MHC class I-mediated presentation of long peptides to CTLs may need some modifications to incorporate a novel MHC class I function of lipopeptide Ag presentation. - Conditional IFNAR1 ablation reveals distinct requirements of Type I IFN signaling for NK cell maturation and tumor surveillance.
Tatsuaki Mizutani, Nina Neugebauer, Eva M Putz, Nadine Moritz, Olivia Simma, Eva Zebedin-Brandl, Dagmar Gotthardt, Wolfgang Warsch, Eva Eckelhart, Hans-Peter Kantner, Ulrich Kalinke, Stefan Lienenklaus, Siegfried Weiss, Birgit Strobl, Mathias Müller, Veronika Sexl, Dagmar Stoiber
Oncoimmunology, 1, 7, 1027, 1037, 01 Oct. 2012, [Peer-reviewed], [Lead author], [International Magazine]
English, Mice with an impaired Type I interferon (IFN) signaling (IFNAR1- and IFNβ-deficient mice) display an increased susceptibility toward v-ABL-induced B-cell leukemia/lymphoma. The enhanced leukemogenesis in the absence of an intact Type I IFN signaling is caused by alterations within the tumor environment. Deletion of Ifnar1 in tumor cells (as obtained in Ifnar1(f/f) CD19-Cre mice) failed to impact on disease latency or type. In line with this observation, the initial transformation and proliferative capacity of tumor cells were unaltered irrespective of whether the cells expressed IFNAR1 or not. v-ABL-induced leukemogenesis is mainly subjected to natural killer (NK) cell-mediated tumor surveillance. Thus, we concentrated on NK cell functions in IFNAR1 deficient animals. Ifnar1(-/-) NK cells displayed maturation defects as well as an impaired cytolytic activity. When we deleted Ifnar1 selectively in mature NK cells (by crossing Ncr1-iCre mice to Ifnar1(f/f) animals), maturation was not altered. However, NK cells derived from Ifnar1(f/f) Ncr1-iCre mice showed a significant cytolytic defect in vitro against the hematopoietic cell lines YAC-1 and RMA-S, but not against the melanoma cell line B16F10. Interestingly, this defect was not related to an in vivo phenotype as v-ABL-induced leukemogenesis was unaltered in Ifnar1(f/f )Ncr1-iCre compared with Ifnar1(f/f) control mice. Moreover, the ability of Ifnar1(f/f) Ncr1-iCre NK cells to kill B16F10 melanoma cells was unaltered, both in vitro and in vivo. Our data reveal that despite the necessity for Type I IFN in NK cell maturation the expression of IFNAR1 on mature murine NK cells is not required for efficient tumor surveillance. - Biosensors for BCR-ABL activity and their application to cancer
Yusuke Ohba, Stephanie Darmanin, Tatsuaki Mizutani, Masumi Tsuda, Takeshi Kondo
Biosensors and Cancer, 268, 283, CRC Press, 01 Jan. 2012
English, In book - ZAPS is a potent stimulator of signaling mediated by the RNA helicase RIG-I during antiviral responses.
Sumio Hayakawa, Souichi Shiratori, Hiroaki Yamato, Takeshi Kameyama, Chihiro Kitatsuji, Fumi Kashigi, Showhey Goto, Shoichiro Kameoka, Daisuke Fujikura, Taisho Yamada, Tatsuaki Mizutani, Mika Kazumata, Maiko Sato, Junji Tanaka, Masahiro Asaka, Yusuke Ohba, Tadaaki Miyazaki, Masahiro Imamura, Akinori Takaoka
Nature immunology, 12, 1, 37, 44, Jan. 2011, [Peer-reviewed], [International Magazine]
English, Scientific journal, The poly(ADP-ribose) polymerases (PARPs) participate in many biological and pathological processes. Here we report that the PARP-13 shorter isoform (ZAPS), rather than the full-length protein (ZAP), was selectively induced by 5'-triphosphate-modified RNA (3pRNA) and functioned as a potent stimulator of interferon responses in human cells mediated by the RNA helicase RIG-I. ZAPS associated with RIG-I to promote the oligomerization and ATPase activity of RIG-I, which led to robust activation of IRF3 and NF-κB transcription factors. Disruption of the gene encoding ZAPS resulted in impaired induction of interferon-α (IFN-α), IFN-β and other cytokines after viral infection. These results indicate that ZAPS is a key regulator of RIG-I signaling during the innate antiviral immune response, which suggests its possible use as a therapeutic target for viral control. - A novel FRET-based biosensor for the measurement of BCR-ABL activity and its response to drugs in living cells.
Tatsuaki Mizutani, Takeshi Kondo, Stephanie Darmanin, Masumi Tsuda, Shinya Tanaka, Minoru Tobiume, Masahiro Asaka, Yusuke Ohba
Clinical cancer research : an official journal of the American Association for Cancer Research, 16, 15, 3964, 75, 01 Aug. 2010, [Peer-reviewed], [Lead author], [International Magazine]
English, PURPOSE: To develop a novel diagnostic method for the assessment of drug efficacy in chronic myeloid leukemia (CML) patients individually, we generated a biosensor that enables the evaluation of BCR-ABL kinase activity in living cells using the principle of fluorescence resonance energy transfer (FRET). EXPERIMENTAL DESIGN: To develop FRET-based biosensors, we used CrkL, the most characteristic substrate of BCR-ABL, and designed a protein in which CrkL is sandwiched between Venus, a variant of YFP, and enhanced cyan fluorescent protein, so that CrkL intramolecular binding of the SH2 domain to phosphorylated tyrosine (Y207) increases FRET efficiency. After evaluation of the properties of this biosensor by comparison with established methods including Western blotting and flow cytometry, BCR-ABL activity and its response to drugs were examined in CML patient cells. RESULTS: After optimization, we obtained a biosensor that possesses higher sensitivity than that of established techniques with respect to measuring BCR-ABL activity and its suppression by imatinib. Thanks to its high sensitivity, this biosensor accurately gauges BCR-ABL activity in relatively small cell numbers and can also detect <1% minor drug-resistant populations within heterogeneous ones. We also noticed that this method enabled us to predict future onset of drug resistance as well as to monitor the disease status during imatinib therapy, using patient cells. CONCLUSION: In consideration of its quick and practical nature, this method is potentially a promising tool for the prediction of both current and future therapeutic responses in individual CML patients, which will be surely beneficial for both patients and clinicians. - Homeostatic erythropoiesis by the transcription factor IRF2 through attenuation of type I interferon signaling.
Tatsuaki Mizutani, Kohichiro Tsuji, Yasuhiro Ebihara, Shinsuke Taki, Yusuke Ohba, Tadatsugu Taniguchi, Kenya Honda
Experimental hematology, 36, 3, 255, 64, Mar. 2008, [Peer-reviewed], [Lead author], [International Magazine]
English, OBJECTIVE: Erythrocyte production is tightly regulated by cytokines, particularly erythropoietin (EPO), which affects expansion and viability of erythroid lineage cells via induction of several factors, including Bcl2-like 1 (Bcl-XL). Because type I interferon (IFN) is known to inhibit erythropoiesis, we studied mice deficient in the gene for interferon regulatory factor 2 (IRF2), which functions as a negative regulator of type I IFN signaling, in the context of erythropoiesis regulation. MATERIALS AND METHODS: We performed hematologic analyses and detected normocytic anemia in Irf2-deficient mice. RESULTS: Assessment of the maturation of erythroid progenitors in Irf2-deficient bone marrow by flow cytometry revealed a decreased number of late erythroblasts accompanied by an increased number of early erythroid progenitors. Irf2-deficient mice manifested elevated serum EPO levels, decreased Bcl-XL expression levels and enhanced apoptosis of erythroblasts, which may account for the decreased number of late erythroblasts. We further assessed the role of IRF2 in the regulation of type I IFN signaling during erythropoiesis, and found that additional homozygous mutation of IFNAR1, a subunit of type I IFN receptor complex, led to rescue of the defect of erythropoiesis in Irf2-deficient mice. CONCLUSIONS: Impaired erythropoiesis in Irf2-deficient mice results from excessive type I IFN signaling, which inhibits Bcl-XL expression in erythroid lineage cells. Our present study provides a mechanistic understanding of the potential cross-talk between type I IFN and EPO signaling pathways during erythropoiesis and may offer therapeutic insights into anemia. - IRF family transcription factors in type I interferon induction
Hideyuki Yanai, Tatsuaki Mizutani, Takayuki Inuzuka, Kenya Honda, Akinori Takaoka, Tadatsugu Taniguchi
International Congress Series, 1285, 104, 113, Nov. 2005, [Peer-reviewed], [Invited]
English, Scientific journal - Spatiotemporal regulation of MyD88-IRF-7 signalling for robust type-I interferon induction.
Kenya Honda, Yusuke Ohba, Hideyuki Yanai, Hideo Negishi, Tatsuaki Mizutani, Akinori Takaoka, Choji Taya, Tadatsugu Taniguchi
Nature, 434, 7036, 1035, 40, 21 Apr. 2005, [Peer-reviewed], [International Magazine]
English, Robust type-I interferon (IFN-alpha/beta) induction in plasmacytoid dendritic cells, through the activation of Toll-like receptor 9 (TLR9), constitutes a critical aspect of immunity. It is absolutely dependent on the transcription factor IRF-7, which interacts with and is activated by the adaptor MyD88. How plasmacytoid dendritic cells, but not other cell types (such as conventional dendritic cells), are able to activate the MyD88-IRF-7-dependent IFN induction pathway remains unknown. Here we show that the spatiotemporal regulation of MyD88-IRF-7 signalling is critical for a high-level IFN induction in response to TLR9 activation. The IFN-inducing TLR9 ligand, A/D-type CpG oligodeoxynucleotide (CpG-A), is retained for long periods in the endosomal vesicles of plasmacytoid dendritic cells, together with the MyD88-IRF-7 complex. However, in conventional dendritic cells, CpG-A is rapidly transferred to lysosomal vesicles. We further show that conventional dendritic cells can also mount a robust IFN induction if CpG-A is manipulated for endosomal retention using a cationic lipid. This strategy also allows us to demonstrate endosomal activation of the IFN pathway by the otherwise inactive TLR9 ligand B/K-type oligodeoxynucleotide (CpG-B). Thus, our study offers insights into the regulation of TLR9 signalling in space, potentially suggesting a new avenue for therapeutic intervention. - IRF-7 is the master regulator of type-I interferon-dependent immune responses.
Kenya Honda, Hideyuki Yanai, Hideo Negishi, Masataka Asagiri, Mitsuharu Sato, Tatsuaki Mizutani, Naoya Shimada, Yusuke Ohba, Akinori Takaoka, Nobuaki Yoshida, Tadatsugu Taniguchi
Nature, 434, 7034, 772, 7, 07 Apr. 2005, [Peer-reviewed], [International Magazine]
English, Scientific journal, The type-I interferon (IFN-alpha/beta) response is critical to immunity against viruses and can be triggered in many cell types by cytosolic detection of viral infection, or in differentiated plasmacytoid dendritic cells by the Toll-like receptor 9 (TLR9) subfamily, which generates signals via the adaptor MyD88 to elicit robust IFN induction. Using mice deficient in the Irf7 gene (Irf7-/- mice), we show that the transcription factor IRF-7 is essential for the induction of IFN-alpha/beta genes via the virus-activated, MyD88-independent pathway and the TLR-activated, MyD88-dependent pathway. Viral induction of MyD88-independent IFN-alpha/beta genes is severely impaired in Irf7-/- fibroblasts. Consistently, Irf7-/- mice are more vulnerable than Myd88-/- mice to viral infection, and this correlates with a marked decrease in serum IFN levels, indicating the importance of the IRF-7-dependent induction of systemic IFN responses for innate antiviral immunity. Furthermore, robust induction of IFN production by activation of the TLR9 subfamily in plasmacytoid dendritic cells is entirely dependent on IRF-7, and this MyD88-IRF-7 pathway governs the induction of CD8+ T-cell responses. Thus, all elements of IFN responses, whether the systemic production of IFN in innate immunity or the local action of IFN from plasmacytoid dendritic cells in adaptive immunity, are under the control of IRF-7. - Integral role of IRF-5 in the gene induction programme activated by Toll-like receptors.
Akinori Takaoka, Hideyuki Yanai, Seiji Kondo, Gordon Duncan, Hideo Negishi, Tatsuaki Mizutani, Shin-Ichi Kano, Kenya Honda, Yusuke Ohba, Tak W Mak, Tadatsugu Taniguchi
Nature, 434, 7030, 243, 9, 10 Mar. 2005, [Peer-reviewed], [International Magazine]
English, The activation of Toll-like receptors (TLRs) is central to innate and adaptive immunity. All TLRs use the adaptor MyD88 for signalling, but the mechanisms underlying the MyD88-mediated gene induction programme are as yet not fully understood. Here, we demonstrate that the transcription factor IRF-5 is generally involved downstream of the TLR-MyD88 signalling pathway for gene induction of proinflammatory cytokines, such as interleukin-6 (IL-6), IL-12 and tumour-necrosis factor-alpha. In haematopoietic cells from mice deficient in the Irf5 gene (Irf5-/- mice), the induction of these cytokines by various TLR ligands is severely impaired, whereas interferon-alpha induction is normal. We also provide evidence that IRF-5 interacts with and is activated by MyD88 and TRAF6, and that TLR activation results in the nuclear translocation of IRF-5 to activate cytokine gene transcription. Consistently, Irf5-/- mice show resistance to lethal shock induced by either unmethylated DNA or lipopolysaccharide, which correlates with a marked decrease in the serum levels of proinflammatory cytokines. Thus, our study identifies IRF-5 as a new, principal downstream regulator of the TLR-MyD88 signalling pathway and a potential target of therapeutic intervention to control harmful immune responses. - Role of a transductional-transcriptional processor complex involving MyD88 and IRF-7 in Toll-like receptor signaling.
Kenya Honda, Hideyuki Yanai, Tatsuaki Mizutani, Hideo Negishi, Naoya Shimada, Nobutaka Suzuki, Yusuke Ohba, Akinori Takaoka, Wen-Chen Yeh, Tadatsugu Taniguchi
Proceedings of the National Academy of Sciences of the United States of America, 101, 43, 15416, 21, 26 Oct. 2004, [Peer-reviewed], [International Magazine]
English, Toll-like receptor (TLR) activation is central to immunity, wherein the activation of the TLR9 subfamily members TLR9 and TLR7 results in the robust induction of type I IFNs (IFN-alpha/beta) by means of the MyD88 adaptor protein. However, it remains unknown how the TLR signal "input" can be processed through MyD88 to "output" the induction of the IFN genes. Here, we demonstrate that the transcription factor IRF-7 interacts with MyD88 to form a complex in the cytoplasm. We provide evidence that this complex also involves IRAK4 and TRAF6 and provides the foundation for the TLR9-dependent activation of the IFN genes. The complex defined in this study represents an example of how the coupling of the signaling adaptor and effector kinase molecules together with the transcription factor regulate the processing of an extracellular signal to evoke its versatile downstream transcriptional events in a cell. Thus, we propose that this molecular complex may function as a cytoplasmic transductional-transcriptional processor. - Crystal structure of the calcium pump with a bound ATP analogue.
Chikashi Toyoshima, Tatsuaki Mizutani
Nature, 430, 6999, 529, 35, 29 Jul. 2004, [Peer-reviewed], [International Magazine]
English, P-type ATPases are ATP-powered ion pumps that establish ion concentration gradients across cell and organelle membranes. Here, we describe the crystal structure of the Ca2+ pump of skeletal muscle sarcoplasmic reticulum, a representative member of the P-type ATPase superfamily, with an ATP analogue, a Mg2+ and two Ca2+ ions in the respective binding sites. In this state, the ATP analogue reorganizes the three cytoplasmic domains (A, N and P), which are widely separated without nucleotide, by directly bridging the N and P domains. The structure of the P-domain itself is altered by the binding of the ATP analogue and Mg2+. As a result, the A-domain is tilted so that one of the transmembrane helices moves to lock the cytoplasmic gate of the transmembrane Ca2+-binding sites. This appears to be the mechanism for occluding the bound Ca2+ ions, before releasing them into the lumen of the sarcoplasmic reticulum. - Negative regulation of IFN-alpha/beta signaling by IFN regulatory factor 2 for homeostatic development of dendritic cells.
Kenya Honda, Tatsuaki Mizutani, Tadatsugu Taniguchi
Proceedings of the National Academy of Sciences of the United States of America, 101, 8, 2416, 21, 24 Feb. 2004, [Peer-reviewed], [International Magazine]
English, The development and cooperation of distinct subsets of antigen-presenting cells, particularly dendritic cells (DCs), may be critical for maintaining homeostatic immune responses. Recently, much attention has been focused on IFN-alpha/beta, the cytokines induced en masse by virus infection or the activation of Toll-like receptors, in the context of DC activation. Here, we show that mice deficient in IFN regulatory factor 2 exhibit selective loss of CD8alpha- DCs, the so-called myeloid DCs, which is accompanied by a notable increase in CD11c-CD11bhigh other myeloid lineage cells. Such deficiency is intrinsic to the bone marrow precursors, in which the abnormal induction of IFN-alpha/beta genes causes excessive IFN signaling. The critical function of IFN regulatory factor 2 in the negative regulation of IFN-alpha/beta signaling is underscored by the observation that the deficiency is rescued by introducing an additional null mutation for the IFN receptor complex. In view of accumulating evidence of the critical role of IFN-alpha/beta signaling in DC activation, our present study offers a unique example in that the magnitude of a cytokine signal should be properly balanced in a stage-specific manner during the differentiation and activation of DCs. - Essential role of IRF-3 in lipopolysaccharide-induced interferon-beta gene expression and endotoxin shock.
Shinya Sakaguchi, Hideo Negishi, Masataka Asagiri, Chigusa Nakajima, Tatsuaki Mizutani, Akinori Takaoka, Kenya Honda, Tadatsugu Taniguchi
Biochemical and biophysical research communications, 306, 4, 860, 6, 11 Jul. 2003, [Peer-reviewed], [International Magazine]
English, Scientific journal, Type I interferons (IFN-alpha/beta) affect many aspects of immune responses. Many pathogen-associated molecules, including bacterial lipopolysaccharide (LPS) and virus-associated double-stranded RNA, induce IFN gene expression through activation of distinct Toll-like receptors (TLRs). Although much has been studied about the activation of the transcription factor IRF-3 and induction of IFN-beta gene by the LPS-mediated TLR4 signaling, definitive evidence is missing about the actual role of IRF-3 in LPS responses in vitro and in vivo. Using IRF-3 deficient mice, we show here that IRF-3 is indeed essential for the LPS-mediated IFN-beta gene induction. Loss of IRF-3 also affects the expression of profile of other cytokine/chemokine genes. We also provide evidence that the LPS/TLR4 signaling activates IRF-7 to induce IFN-beta, if IRF-7 is induced by IFNs prior to LPS simulation. Finally, the IRF-3-deficient mice show resistance to LPS-induced endotoxin shock. These results place IRF-3 as a molecule central to LPS/TLR4 signaling.
Other Activities and Achievements
- 肉芽腫深部における好中球主導型マクロファージM2化機構
水谷龍明, 杉田昌彦, 医学の歩み, 289, 12, 907, 908, Jun. 2024, [Invited], [Lead author, Corresponding author] - アレナウイルスZ蛋白の自己重合を検出するFRETバイオセンサーの開発と,それを利用した抗ウイルス薬スクリーニング法の確立
水谷龍明, 大場雄介, 水田賢志, 浦田秀造, 日本蛋白質科学会年会プログラム・要旨集, 23rd (CD-ROM), 2023 - 【グローバル時代の新興再興感染症への科学的アプローチ】デング・ジカ・SFTS・出血熱へのアプローチ ラッサウイルス・エボラウイルスに対する創薬研究
泉澤 文子, 水谷 龍明, 浦田 秀造, 生体の科学, 72, 4, 326, 329, Aug. 2021
(公財)金原一郎記念医学医療振興財団, Japanese - S100A9は抗腫瘍型M1-TAMを誘導し、腫瘍成長を抑制する
大和 勇輝, 水谷 龍明, 日本癌学会総会記事, 79回, OJ12, 2, Oct. 2020
(一社)日本癌学会, English - Identification of novel chemical compounds which inhibited filovirus VP40-mediated virus-like particle (VLP) production
浦田秀造, 浦田秀造, OMOTUYI Olaposi Idowu, 石川岳志, 水田賢志, 櫻井康晃, 櫻井康晃, 水谷龍明, 植田弘師, 田中義正, 安田二朗, 安田二朗, 安田二朗, 日本薬学会年会要旨集(CD-ROM), 140th (Web), 27F, pm12, 2020
(公社)日本薬学会, Japanese - 抗ラッサウイルス作用を有するリード阻害剤の創出
水谷龍明, 浦田秀造, 水田賢志, 大場雄介, 長崎大学熱帯医学研究拠点共同研究報告集, 2018, 2019 - フィロウイルスVP40による粒子形成を阻害する新規化合物の同定
浦田秀造, 石川岳志, 水田賢志, OLAPOSI Omotuyi, 水谷龍明, 植田弘師, 田中義正, 安田二朗, 安田二朗, 日本ウイルス学会学術集会プログラム・予稿集(Web), 67th, 2019 - 結核肉芽腫形成を制御する好中球機能の解明
水谷 龍明, 吉岡 祐弥, 大内 結貴, 森田 大輔, 杉田 昌彦, 生命科学系学会合同年次大会, 2017年度, [4LT24, 02(3P, Dec. 2017
生命科学系学会合同年次大会運営事務局, Japanese - 【非結核性抗酸菌症の今日的問題】 脂質免疫の新視点から見た非結核性抗酸菌感染症
水谷 龍明, 杉田 昌彦, 化学療法の領域, 32, 8, 1477, 1483, Jul. 2016
(株)医薬ジャーナル社, Japanese - NK細胞の抗腫瘍活性におけるインターフェロンシグナルの役割
MIZUTANI TATSUAKI, MIZUTANI TATSUAKI, NEUGEBAUER NINA, PUTZ EVA M, SEXL VERONIKA, STOIBER DAGMAR, STOIBER DAGMAR, 日本分子生物学会年会プログラム・要旨集(Web), 37th, 2P-0804 (WEB ONLY), 2014
Japanese - 抗ウイルス応答において活性化されるRIG-Iの強力な調節因子ZAPSの同定
白鳥 聡一, 早川 清雄, 大和 弘明, 亀山 武志, 北辻 千展, 樫木 芙美, 後藤 翔平, 亀岡 章一郎, 藤倉 大輔, 山田 大翔, 水谷 龍明, 数馬田 美香, 佐藤 麻衣子, 田中 淳司, 浅香 正博, 大場 雄介, 宮崎 忠昭, 今村 雅寛, 高岡 晃教, 北海道醫學雜誌 = Acta medica Hokkaidonensia, 87, 4, 194, 194, 01 Aug. 2012
Japanese - The role of STAT3 alpha in Pten-dependent hematopoietic malignancy
Tatsuaki Mizutani, Emilio Casanova, Dagmar Stoiber, CANCER RESEARCH, 72, Apr. 2012
English, Summary international conference - 慢性骨髄白血病に対する分子標的治療薬の反応性・抵抗性判定試験(Seeing response and resistance to BCR-ABL inhibition in chronic myeloid leukemia)
大場 雄介, 金安 顕子, 水谷 龍明, ダルマニン・ステファニー, 近藤 健, 津田 真寿美, 日本癌学会総会記事, 70回, 242, 242, Sep. 2011
日本癌学会, English - 自然免疫系における核酸認識受容体を介したシグナルの新規調節因子と抗ウイルス作用
KAMEYAMA TAKESHI, HAYAKAWA SUMIO, SHIRATORI TOSHIKAZU, YAMATO HIROAKI, KITATSUJI CHIHIRO, KASHIKI FUMI, GOTO SHOHEI, KAMEOKA SHOICHIRO, FUJIKURA DAISUKE, MIZUTANI TATSUAKI, KAZUMATA MIKA, SATO MAIKO, IMAMURA MASAHIRO, ASAKA MASAHIRO, OBA YUSUKE, MIYAZAKI TADAAKI, TAKAOKA AKINORI, 日本ウイルス学会学術集会プログラム・抄録集, 58th, 220, 15 Oct. 2010
Japanese - FRETバイオセンサーを用いたCML分子標的薬剤の薬効評価系の構築(A FRET-based biosensor for the evaluation of the efficacy of molecular targeted drugs for chronic myeloid leukemia)
水谷 龍明, 近藤 健, ダルマニン・ステファニー, 津田 真寿美, 田中 伸哉, 浅香 正博, 大場 雄介, 日本癌学会総会記事, 68回, 457, 457, Aug. 2009
日本癌学会, English - 慢性骨髄性白血病に対する分子標的治療薬の新たな薬効評価系の構築
MIZUTANI TATSUAKI, KONDO TAKESHI, STEPHANIE DARMANIN, TSUDA MASUMI, KAWAGUCHI HIDEAKI, ASAKA MASAHIRO, OBA YUSUKE, 日本病理学会会誌, 98, 1, 278, 20 Mar. 2009
Japanese - 慢性骨髄性白血病に対する分子標的治療薬の新たな薬効評価系の構築
MIZUTANI TATSUAKI, KONDO TAKESHI, DARMANIN STEPHANIE, TSUDA MASUMI, KAIHARA TAKUMA, KAWAGUCHI HIDEAKI, ASAKA MASAHIRO, OBA YUSUKE, 生化学, 4P-1171, 2008
Japanese - 慢性骨髄性白血病に対する新たな診断技術の開発
MIZUTANI TATSUAKI, TSUDA MASUMI, KAWAGUCHI HIDEAKI, OBA YUSUKE, 生化学, 4P-0935, 2007
Japanese - 樹状細胞群の分化と活性化の分子機構
HONDA KEN'YA, YANAI HIROYUKI, MIZUTANI TATSUAKI, NEGISHI HIDEO, OBA YUSUKE, TAKAOKA AKINORI, TANIGUCHI TADATSUGU, 日本分子生物学会年会プログラム・講演要旨集, 27th, 345, 25 Nov. 2004
Japanese - 樹状細胞群におけるIRFファミリー転写因子の役割
YANAI HIDEYUKI, HONDA KEN'YA, ASAGIRI MASATAKA, NEGISHI HIDEO, MIZUTANI TATSUAKI, SHIMADA NAOYA, YOSHIDA NOBUAKI, OBA YUSUKE, TAKAOKA AKINORI, 日本分子生物学会年会プログラム・講演要旨集, 27th, 593, 25 Nov. 2004
Japanese - LPS応答における転写因子IRF‐3の機能解析
SAKAGUCHI SHIN'YA, NEGISHI HIDEO, ASAGIRI SHIGETAKA, NAKAJIMA CHIGUSA, MIZUTANI TATSUAKI, TAKAOKA AKINORI, HONDA KEN'YA, TANIGUCHI KOREAKI, 日本免疫学会総会・学術集会記録, 33, 124, 05 Nov. 2003
Japanese
Lectures, oral presentations, etc.
- Neutrophil/macrophage interactions in deep granulomas
水谷龍明, 杉田昌彦
第46回分子生物学会年会, 07 Dec. 2023, Poster presentation
06 Dec. 2023 - 08 Dec. 2023 - Neutrophil S100A9-Cox2 axis dictates the formation of the M2 macrophage niche in granulomas
Tatsuaki Mizutani, Toshiaki Ano, Yuya Yoshioka, Satoshi Mizuta, Keiko Takemoto, Nagatoshi Fujiwara, Masahiko Sugita
The 29th East Asia Joint Symposium, 25 Oct. 2023, English, Oral presentation
24 Oct. 2023 - 27 Oct. 2023 - 好中球S100A9による肉芽腫M2マクロファージの誘導機序,
水谷龍明, 阿野敏明, 水田賢志, 鶴山竜昭, 藤原永年, 杉田昌彦
第34回日本生体防御学会学術総会,, Sep. 2023 - STAT3β plays a tumor-suppressive role in acute myeloid leukemia
Mizutani T, Aigner P, Casanova E, Stoiber D
第82回日本癌学会学術総会, Sep. 2023 - 肉芽腫形成を制御するS100A9
水谷 龍明, 吉岡佑弥, 杉田昌彦
第29回日本生体防御学会学術総会, Jun. 2018, Japanese, Oral presentation
[Domestic Conference] - 結核肉芽腫形成を制御する好中球機能の解明
水谷龍明
第40回分子生物学会年会（2017年度生命科学系学会合同年次大会, ConBio2017）, Jul. 2017 - Evaluation of BCR-ABL activity in living CML cells by FRET-based monitors
Tatsuaki Mizutani
30th Annual Meeting of the Molecular Biology Society of Japan, Dec. 2007
Courses
- 生理学I
北海道大学
Oct. 2024 - Present - 医学研究法II 生理学・薬理学研究技法
北海道大学医学研究院
Apr. 2024 - Present - ILASセミナー「ウイルス学と免疫学の最前線」
京都大学
Apr. 2018 - Mar. 2023 - ポケットゼミ「ウイルスと免疫」
京都大学
Apr. 2015 - Mar. 2018 - 生命科学入門
長崎大学
Apr. 2013 - Jun. 2013 - 薬理IV
長崎大学
Apr. 2013 - Jun. 2013 - 薬理III
長崎大学
Apr. 2013 - Jun. 2013 - 薬学概論II
長崎大学
Apr. 2013 - Jun. 2013 - メディカルバイオ特論IV
長崎大学大学院
Apr. 2013 - Jun. 2013 - 生命薬科学トピックスI
長崎大学大学院
Apr. 2013 - Jun. 2013
Affiliated academic society
Research Themes
- 癌助長性好中球で生じるS100A9依存的転写調節機能の解明
科学研究費助成事業
01 Apr. 2025 - 31 Mar. 2028
水谷 龍明
日本学術振興会, 基盤研究(C), 北海道大学, 25K10440 - 癌助長性好中球におけるS100A9依存的転写制御メカニズムの解明
科学研究費助成事業 基盤研究(C)
01 Apr. 2022 - 31 Mar. 2025
水谷 龍明
日本学術振興会, 基盤研究(C), 京都大学, 22K07167 - 乳がんを助長する好中球機能分子の同定とその阻害剤探索
橋渡し研究プログラム シーズＨ
Apr. 2023 - Mar. 2025
国立研究開発法人日本医療研究開発機構, 北海道大学, Principal investigator, H055 - Regulation of macrophages polarization by neutrophils: implication in tuberculosis and cancer pathology
Grants-in-Aid for Scientific Research
01 Apr. 2017 - 31 Mar. 2020
Mizutani Tatsuaki
After tuberculosis infection, the granuloma formed with heterogeneously activated macrophages. We have specified S100A9-expressing neutrophils were adjacent to immunosuppressive M2 macrophages in the granulomas. This observation suggested that S100A9/neutrophils motivated the M2 polarization in macrophages. To reveal this novel macrophage polarization pathway more explicitly, we generated S100A9 knockout （A9KO）mice and analyzed the BCG infection model as well as tumor xenograft model. Results obtained from A9KO studies revealed that the neutrophil-derived S100A9 could induce the M2 polarization in macrophages. Molecular analyses also specified that S100A9 upregulated anti-inflammatory cytokines followed by M2 macrophages polarization, which was critical for tuberculosis pathology. Besides, we noticed that less significant lung metastatic potential in A9KO compared to WT mice. These results potentially emphasize that S100A9 dependent M2 polarization could operate in the metastasis.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (C), Kyoto University, 17K08659 - Reproduction of chronic pain model through a reconstitution of neuronal circuit components including LPA priming and iPS cells, and its application for drug discovery
Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (A)
01 Apr. 2014 - 31 Mar. 2017
UEDA Hiroshi
We clarified that LPA signals play roles in the development and maintenance of various types of neuropathic pain models and various types of fibromyalgia models. We then performed the high throughput and in silico screening of inhibitors and their chemical optimizations, and successfully obtained biochemical tools to clarify molecular mechanisms underlying chronic pain and therapeutic lead compounds for drug development. As chronic pain was found to comprise of multiple feed-forward systems including immune system, we performed the in vivo reconstitution of LPA-primed cells (microglia, astrocytes, iPS cells, T-cells). From these studies, we found LPA3-microglia-cytokine and LPA1-astrocytes-chemokine production are involved in the development and maintenance of chronic pain, respectively.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (A), Nagasaki University, 26253077 - Revealing the mechanism of the tumor initiation and development due to the tumor immunosuppression by Prothymosin-alpha.
Grants-in-Aid for Scientific Research Grant-in-Aid for Young Scientists (B)
01 Apr. 2014 - 31 Mar. 2016
Mizutani Tatsuaki
How does cancer escape the host immune system? To reveal the molecular mechanism underlying tumor immunosuppression, I focused on the PTMA, one of the DAMPs, which may release the tumor microenvironment from injured malignant cells. To analyze the physiological interaction between tumor and immune cells, I first developed a novel 3D co-culture system where heterogenous immune cells could be communicated together during a long period. I also developed a novel non-radioactive cellular cytotoxicity assay to evaluate the tumor immunosuppression. In addition to such in vitro assays, I specified one in vivo physiological condition upon bacterial infection is closely similar with tumor microenvironment in terms of the expression of M2 macrophages, which is known to one of the immunosuppressive immune cells. They will be certainly useful tools to understand the uncertain cancer immunosurveillance.
Japan Society for the Promotion of Science, Grant-in-Aid for Young Scientists (B), Kyoto University, 26860038 - 骨髄幹細胞から免疫細胞への分化制御における分子基盤の解明
科学研究費助成事業 特別研究員奨励費
2006 - 2007
水谷 龍明
転写因子IRF-2の遺伝子欠損マウスのin vivo解析から、同マウスの新たな表現型として慢性的貧血症状が新たに見出された。同遺伝子欠損マウスの貧血症状は正球性正色素性貧血に分類され、特にTer119high、CD71high細胞すなわち正染性赤芽球の分化ステージにおいて、高頻度にアポトーシス細胞が観測されることが明らかとなった。赤芽球の生存・増殖に必須とされているBcl-xlの発現量を同遺伝子欠損マウス骨髄細胞を用いてRT-PCRで解析したところ、野生型骨髄細胞と比較して有意に減少していることが見出された。転写因子IRF-2はI型インターフェロン(I型IFN)シグナルの負の調節因子であり、実際に同遺伝子欠損マウス骨髄細胞において過剰なI型IFNシグナル(I型IFN誘導遺伝子であるPKR、OASの高いレベルの発現)が検出された。過剰なI型IFNによる細胞増殖現象はよく知られていることから、赤芽球の分化・増殖抑制に対してもI型IFNが関与していることが推察された。そこで、I型IFN受容体欠損マウスとIRF-2遺伝子欠損マウスとの両欠損マウスを作成し、赤芽球異常を観察したところ、正常に回復された。以上のことより、I型IFNシグナル依存的に赤芽球分化抑制が起こっていることが個体レベルで明らかとなった。これはインターフェロン療法の際に、しばしば引き起こされる副作用の一つである貧血の原因解明につながる研究である。実際に、I型IFNシグナルによって、Bcl-xLの発現抑制がどのような分子メカニズムによるものかを解析すれば、効果的な貧血防止薬剤などの開発が可能であり、副作用の少ないインターフェロン療法の実施が実現する。抑制作用の分子基盤の解明に着手してきたが、未だ有用な手がかりが得られていない。I型IFNによる細胞分化抑制は、赤血球以外にも知られていることから他の抑制機構との比較検討からこの分子基盤解明につなげていきたいと考えている。
日本学術振興会, 特別研究員奨励費, 06J10441
