研究者基本情報

• 博士（獣医学）, 北海道大学

• https://researchmap.jp/tomohisat

• https://jglobal.jst.go.jp/detail?JGLOBAL_ID=201801006235298631
• https://orcid.org/0000-0002-6343-0230

• 30585310

• https://orcid.org/0000-0002-6343-0230

• 201801006235298631

研究活動情報

• Identification of claudin-3 as an entry factor for rat hepacivirus
  Tomohisa Tanaka; Yasunori Akaike; Hirotake Kasai; Atsuya Yamashita; Yoshiharu Matsuura; Kohji Moriishi
  Proceedings of the National Academy of Sciences, 122, 40, Proceedings of the National Academy of Sciences, 2025年10月02日
  研究論文（学術雑誌）, Approximately 58 million people worldwide are believed to be infected with hepatitis C virus (HCV), a major causative agent of chronic liver diseases. Hepacivirus ratti strain rn-1, which was discovered from Rattus norvegicus (Norway rat) and designated Norway rat hepacivirus 1 (NRHV1), shares similar properties with HCV in terms of genetic homology, target cell tropism, pathogenicity, and the immune response. In vivo infection systems for NRHV1 will help overcome the challenges in HCV research for vaccine development. However, the virological characteristics of NRHV1, such as the mechanisms of cell entry, remain largely unexplored, in part owing to a paucity of cell culture systems for NRHV1. Here, we identified the host factors that facilitate NRHV1 entry by profiling the gene expression of two cell lines with different susceptibilities to NRHV1 infection. NRHV1 employs rodent orthologues of HCV entry factors, including scavenger receptor class BI, CD81, and occludin, and utilizes claudin-3 (CLDN3) but not claudin-1. The expression of rat and mouse, but not human, CLDN3 facilitates the entry of NRHV1 into murine cell lines that are nonsusceptible to NRHV1 infection. The host-specific cell entry of CLDN3 is determined by two amino acid residues, Ile ⁴⁴ and Trp ⁴⁶ , in extracellular loop 1. These findings suggest that CLDN3 serves as an entry factor for rat hepacivirus.
• Berberine promotes K48-linked polyubiquitination of HNF4α, leading to the inhibition of HBV replication.
  Atsuya Yamashita; Hirotake Kasai; Shinya Maekawa; Tomohisa Tanaka; Yasunori Akaike; Akihide Ryo; Nobuyuki Enomoto; Kohji Moriishi
  Antiviral research, 232, 106027, 106027, 2024年11月01日, ［国際誌］
  英語, 研究論文（学術雑誌）, The current antiviral agents for the treatment of chronic infection with hepatitis B virus (HBV) do not completely remove covalently closed circular DNA (cccDNA) and integrated viral DNA fragments from patients. Berberine is an isoquinoline alkaloid extracted from various plants and has been reported to inhibit the replication of various types of DNA. In this study, we tested the effects of berberine and its derivatives on HBV infection. Berberine inhibited viral core promoter activity at the highest level among the compounds tested and suppressed HBV production and cccDNA synthesis in primary human hepatocytes and HBV-infected HepG2-NTCP cells at an EC50 value of 3.6 μM and a CC50 value of over 240.0 μM. Compared with other viral promoter activities, berberine treatment potently downregulated core promoter activity and reduced protein levels, but not RNA levels, of hepatic nuclear factor 4α (HNF4α), which primarily enhances enhancer II/core promoter activity. Furthermore, berberine treatment enhanced K48-linked, but not K63-linked, polyubiquitination and subsequent proteasome-dependent degradation of HNF4α. These results suggest that berberine enhances the polyubiquitination- and proteasome-dependent degradation of HNF4α and then inhibits HBV replication via the suppression of core promoter activity. The development of antiviral agents based on berberine may contribute to the amelioration of HBV-related disorders, regardless of the presence of residual cccDNA or integrated viral DNA fragments.
• HCV infection activates the proteasome via PA28γ acetylation and heptamerization to facilitate the degradation of RNF2, a catalytic component of polycomb repressive complex 1.
  Hirotake Kasai; Atsuya Yamashita; Yasunori Akaike; Tomohisa Tanaka; Yoshiharu Matsuura; Kohji Moriishi
  mBio, e0169124, 2024年09月27日, ［国際誌］
  英語, 研究論文（学術雑誌）, We previously reported that hepatitis C virus (HCV) infection or HCV core protein expression induces HOX gene expression by impairing histone H2A monoubiquitination via a proteasome-dependent reduction in the level of RNF2, a key catalytic component of polycomb repressive complex 1 (H. Kasai, K. Mochizuki, T. Tanaka, A. Yamashita, et al., J Virol 95:e01784-20, 2021, https://doi.org/10.1128/jvi.01784-20). In this study, we aimed to investigate the mechanism by which HCV infection accelerates RNF2 degradation. Yeast two-hybrid screening and an immunoprecipitation assay revealed that RNF2 is a PA28γ-binding protein. The proteasome activator PA28γ destabilized the RNF2 protein in a proteasome-dependent manner, since RNF2 degradation was impaired by PA28γ knockout or MG132 treatment. HCV infection or core protein expression reduced the levels of RNF2 and histone H2A K119 monoubiquitination and induced the expression of HOX genes in the presence of PA28γ, while PA28γ knockout reversed these changes. Treatment with a lysine acetyltransferase inhibitor inhibited the acetylation of PA28γ at K195 and the degradation of the RNF2 protein, while treatment with a lysine deacetylase inhibitor accelerated these events in a PA28γ-dependent manner. RNF2 protein degradation was increased by expression of the acetylation mimetic PA28γ mutant but not by expression of the acetylation-defective mutant or the proteasome activation-defective mutant. Furthermore, HCV infection or core protein expression facilitated the interaction between PA28γ and the lysine acetyltransferase CBP/p300 and then accelerated PA28γ acetylation and heptazmerization to promote RNF2 degradation. These data suggest that HCV infection accelerates the acetylation-dependent heptamerization of PA28γ to increase the proteasomal targeting of RNF2.IMPORTANCEHCV is a causative agent of HCV-related liver diseases, including hepatic steatosis, cirrhosis, and hepatocellular carcinoma. PA28γ, which, in heptameric form, activates the 20S core proteasome for the degradation of PA28γ-binding proteins, is responsible for HCV-related liver diseases. HCV core protein expression or HCV infection accelerates RNF2 degradation, leading to the induction of HOX gene expression via a decrease in the level of H2Aub on HOX gene promoters. However, the mechanism of RNF2 degradation in HCV-infected cells has not been clarified. The data presented in this study suggest that PA28γ acetylation and heptamerization are promoted by HCV infection or by core protein expression to activate the proteasome for the degradation of RNF2 and are responsible for HCV propagation. This study provides novel insights valuable for the development of therapies targeting both HCV propagation and HCV-related diseases.
• SARS-CoV-2 papain-like protease inhibits ISGylation of the viral nucleocapsid protein to evade host anti-viral immunity.
  Aulia Fitri Rhamadianti; Takayuki Abe; Tomohisa Tanaka; Chikako Ono; Hisashi Katayama; Yoshiteru Makino; Lin Deng; Chieko Matsui; Kohji Moriishi; Fumi Shima; Yoshiharu Matsuura; Ikuo Shoji
  Journal of virology, 98, 9, e0085524, 2024年09月17日, ［国際誌］
  英語, 研究論文（学術雑誌）, A severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection causes mild-to-severe respiratory symptoms, including acute respiratory distress. Despite remarkable efforts to investigate the virological and pathological impacts of SARS-CoV-2, many of the characteristics of SARS-CoV-2 infection still remain unknown. The interferon-inducible ubiquitin-like protein ISG15 is covalently conjugated to several viral proteins to suppress their functions. It was reported that SARS-CoV-2 utilizes its papain-like protease (PLpro) to impede ISG15 conjugation, ISGylation. However, the role of ISGylation in SARS-CoV-2 infection remains unclear. We aimed to elucidate the role of ISGylation in SARS-CoV-2 replication. We observed that the SARS-CoV-2 nucleocapsid protein is a target protein for the HERC5 E3 ligase-mediated ISGylation in cultured cells. Site-directed mutagenesis reveals that the residue K374 within the C-terminal spacer B-N3 (SB/N3) domain is required for nucleocapsid-ISGylation, alongside conserved lysine residue in MERS-CoV (K372) and SARS-CoV (K375). We also observed that the nucleocapsid-ISGylation results in the disruption of nucleocapsid oligomerization, thereby inhibiting viral replication. Knockdown of ISG15 mRNA enhanced SARS-CoV-2 replication in the SARS-CoV-2 reporter replicon cells, while exogenous expression of ISGylation components partially hampered SARS-CoV-2 replication. Taken together, these results suggest that SARS-CoV-2 PLpro inhibits ISGylation of the nucleocapsid protein to promote viral replication by evading ISGylation-mediated disruption of the nucleocapsid oligomerization.IMPORTANCEISG15 is an interferon-inducible ubiquitin-like protein that is covalently conjugated to the viral protein via specific Lys residues and suppresses viral functions and viral propagation in many viruses. However, the role of ISGylation in SARS-CoV-2 infection remains largely unclear. Here, we demonstrated that the SARS-CoV-2 nucleocapsid protein is a target protein for the HERC5 E3 ligase-mediated ISGylation. We also found that the residue K374 within the C-terminal spacer B-N3 (SB/N3) domain is required for nucleocapsid-ISGylation. We obtained evidence suggesting that nucleocapsid-ISGylation results in the disruption of nucleocapsid-oligomerization, thereby suppressing SARS-CoV-2 replication. We discovered that SARS-CoV-2 papain-like protease inhibits ISG15 conjugation of nucleocapsid protein via its de-conjugating enzyme activity. The present study may contribute to gaining new insight into the roles of ISGylation-mediated anti-viral function in SARS-CoV-2 infection and may lead to the development of more potent and selective inhibitors targeted to SARS-CoV-2 nucleocapsid protein.
• Identification of neutralizing epitopes in the preS2 domain of the hepatitis B virus.
  Keigo Yato; Mami Matsuda; Kento Fukano; Tomohisa Tanaka; Kohji Moriishi; Hironori Nishitsuji; Kunitada Shimotohno; Koji Tamura; Takaji Wakita; Masamichi Muramatsu; Takanobu Kato; Ryosuke Suzuki
  Virus research, 323, 199014, 199014, 2023年01月02日, ［国際誌］
  英語, 研究論文（学術雑誌）, Hepatitis B virus (HBV) infection is a major public health problem. The sodium taurocholate cotransporting polypeptide (NTCP) has been identified as an essential HBV receptor. Human hepatocytes are infected with HBV via binding between the preS1 region of the HBV large envelope protein and the NTCP. However, the role of preS2 in HBV entry is not well understood. In this study, we induced anti-preS2 serum in mice by DNA immunization, and showed that the resulting antiserum neutralized HBV infectivity. Competition assays using overlapping peptides suggested that the neutralizing epitope is located in the N-terminal region of preS2. In addition, monoclonal antibodies targeting the N-terminal region of preS2 neutralized HBV infectivity, indicating that these domains are critical epitopes for viral neutralization. These findings provide new insights into the HBV entry machinery while suggesting a novel modality for the prevention and treatment of HBV infection.
• Neutralization of hepatitis B virus with vaccine-escape mutations by hepatitis B vaccine with large-HBs antigen
  Ayaka Washizaki; Asako Murayama; Megumi Murata; Tomoko Kiyohara; Keigo Yato; Norie Yamada; Hussein Hassan Aly; Tomohisa Tanaka; Kohji Moriishi; Hironori Nishitsuji; Kunitada Shimotohno; Yasumasa Goh; Ken J. Ishii; Hiroshi Yotsuyanagi; Masamichi Muramatsu; Koji Ishii; Yoshimasa Takahashi; Ryosuke Suzuki; Hirofumi Akari; Takanobu Kato
  Nature Communications, 13, 1, Springer Science and Business Media LLC, 2022年09月05日
  研究論文（学術雑誌）, Abstract
  
  Although the current hepatitis B (HB) vaccine comprising small-HBs antigen (Ag) is potent and safe, attenuated prophylaxis against hepatitis B virus (HBV) with vaccine-escape mutations (VEMs) has been reported. We investigate an HB vaccine consisting of large-HBsAg that overcomes the shortcomings of the current HB vaccine. Yeast-derived large-HBsAg is immunized into rhesus macaques, and the neutralizing activities of the induced antibodies are compared with those of the current HB vaccine. Although the antibodies induced by the current HB vaccine cannot prevent HBV infection with VEMs, the large-HBsAg vaccine-induced antibodies neutralize those infections. The HBV genotypes that exhibited attenuated neutralization via these vaccines are different. Here, we show that the HB vaccine consisting of large-HBsAg is useful to compensate for the shortcomings of the current HB vaccine. The combined use of these HB vaccines may induce antibodies that can neutralize HBV strains with VEMs or multiple HBV genotypes.
• Hydrophobic Alpha-Helical Short Peptides in Overlapping Reading Frames of the Coronavirus Genome
  Takashi Okura; Kazuya Shirato; Masatoshi Kakizaki; Satoko Sugimoto; Shutoku Matsuyama; Tomohisa Tanaka; Yohei Kume; Mina Chishiki; Takashi Ono; Kohji Moriishi; Masashi Sonoyama; Mitsuaki Hosoya; Koichi Hashimoto; Katsumi Maenaka; Makoto Takeda
  Pathogens, 11, 8, 877, 877, MDPI AG, 2022年08月03日, ［査読有り］, ［国際誌］
  英語, 研究論文（学術雑誌）, In this study, we show that the coronavirus (CoV) genome may encode many functional hydrophobic alpha-helical peptides (HAHPs) in overlapping reading frames of major coronaviral proteins throughout the entire viral genome. These HAHPs can theoretically be expressed from non-canonical sub-genomic (sg)RNAs that are synthesized in substantial amounts in infected cells. We selected and analyzed five and six HAHPs encoded in the S gene regions of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and Middle East respiratory syndrome coronavirus (MERS-CoV), respectively. Two and three HAHPs derived from SARS-CoV-2 and MERS-CoV, respectively, specifically interacted with both the SARS-CoV-2 and MERS-CoV S proteins and inhibited their membrane fusion activity. Furthermore, one of the SARS-CoV-2 HAHPs specifically inhibited viral RNA synthesis by accumulating at the site of viral RNA synthesis. Our data show that a group of HAHPs in the coronaviral genome potentially has a regulatory role in viral propagation.
• SARS-CoV-2 ORF6 disrupts nucleocytoplasmic trafficking to advance viral replication.
  Yoichi Miyamoto; Yumi Itoh; Tatsuya Suzuki; Tomohisa Tanaka; Yusuke Sakai; Masaru Koido; Chiaki Hata; Cai-Xia Wang; Mayumi Otani; Kohji Moriishi; Taro Tachibana; Yoichiro Kamatani; Yoshihiro Yoneda; Toru Okamoto; Masahiro Oka
  Communications biology, 5, 1, 483, 483, 2022年05月19日, ［国際誌］
  英語, 研究論文（学術雑誌）, Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) ORF6 is an antagonist of interferon (IFN)-mediated antiviral signaling, achieved through the prevention of STAT1 nuclear localization. However, the exact mechanism through which ORF6 prevents STAT1 nuclear trafficking remains unclear. Herein, we demonstrate that ORF6 directly binds to STAT1 with or without IFN stimulation, resulting in the nuclear exclusion of STAT1. ORF6 also recognizes importin α subtypes with different modes, in particular, high affinity to importin α1 but a low affinity to importin α5. Although ORF6 potentially disrupts the importin α/importin β1-mediated nuclear transport, thereby suppressing the nuclear translocation of the other classical nuclear localization signal-containing cargo proteins, the inhibitory effect of ORF6 is modest when compared with that of STAT1. The results indicate that the drastic nuclear exclusion of STAT1 is attributed to the specific binding with ORF6, which is a distinct strategy for the importin α1-mediated pathway. Combined with the results from a newly-produced replicon system and a hamster model, we conclude that SARS-CoV-2 ORF6 acts as a virulence factor via regulation of nucleocytoplasmic trafficking to accelerate viral replication, resulting in disease progression.
• Establishment of a stable SARS-CoV-2 replicon system for application in high-throughput screening.
  Tomohisa Tanaka; Akatsuki Saito; Tatsuya Suzuki; Yoichi Miyamoto; Kazuo Takayama; Toru Okamoto; Kohji Moriishi
  Antiviral research, 199, 105268, 105268, 2022年03月, ［国際誌］
  英語, 研究論文（学術雑誌）, Experiments with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are limited by the need for biosafety level 3 (BSL3) conditions. A SARS-CoV-2 replicon system rather than an in vitro infection system is suitable for antiviral screening since it can be handled under BSL2 conditions and does not produce infectious particles. However, the reported replicon systems are cumbersome because of the need for transient transfection in each assay. In this study, we constructed a bacterial artificial chromosome vector (the replicon-BAC vector) including the SARS-CoV-2 replicon and a fusion gene encoding Renilla luciferase and neomycin phosphotransferase II, examined the antiviral effects of several known compounds, and then established a cell line stably harboring the replicon-BAC vector. Several cell lines transiently transfected with the replicon-BAC vector produced subgenomic replicon RNAs (sgRNAs) and viral proteins, and exhibited luciferase activity. In the transient replicon system, treatment with remdesivir or interferon-β but not with camostat or favipiravir suppressed the production of viral agents and luciferase, indicating that luciferase activity corresponds to viral replication. VeroE6/Rep3, a stable replicon cell line based on VeroE6 cells, was successfully established and continuously produced viral proteins, sgRNAs and luciferase, and their production was suppressed by treatment with remdesivir or interferon-β. Molnupiravir, a novel coronavirus RdRp inhibitor, inhibited viral replication more potently in VeroE6/Rep3 cells than in VeroE6-based transient replicon cells. In summary, our stable replicon system will be a powerful tool for the identification of SARS-CoV-2 antivirals through high-throughput screening.
• Establishment of monoclonal antibodies broadly neutralize infection of hepatitis B virus.
  He Zhang; Yumi Itoh; Tatsuya Suzuki; Kan-Ichiro Ihara; Tomohisa Tanaka; Saori Haga; Hajime Enatsu; Maho Yumiya; Mari Kimura; Akira Takada; Daiki Itoh; Yuri Shibazaki; Shuto Nakao; Sachiyo Yoshio; Kei Miyakawa; Yuki Miyamoto; Hanae Sasaki; Tadahiro Kajita; Masaya Sugiyama; Masashi Mizokami; Taro Tachibana; Akihide Ryo; Kohji Moriishi; Eiji Miyoshi; Tatsuya Kanto; Toru Okamoto; Yoshiharu Matsuura
  Microbiology and immunology, 66, 4, 179, 192, 2022年01月27日, ［国際誌］
  英語, 研究論文（学術雑誌）, Antibodies against hepatitis B virus S protein can protect against hepatitis B virus (HBV) infection. Therefore, hepatitis B immunoglobulin (HBIG), which contains HBsAb, is used clinically as a therapy for HBV infection. In this study, a series of monoclonal antibodies that recognize multiple HBV genotypes was obtained. All the antibodies recognized conformational epitopes of S protein, but not linear epitopes. Several antibodies neutralized HBV infection and exhibited strong affinities and neutralizing activities. Antigenic epitope analysis demonstrated that they recognized residue Ile152 of S protein, which is localized outside the "a" determinant. Ile152 is highly conserved, and a mutation in this residue resulted in reduced expression of large hepatitis B surface proteins (L protein), suggesting that the amino acid at this position is involved in the expression of L protein. In addition, the antibodies neutralized the infection of hepatitis D virus possessing a Gly145 mutation to Arg in S protein, which is a well-known escape mutation against HBIG treatment. Using mouse monoclonal antibodies, a humanized antibody possessing affinities and neutralizing activities similar to those of the original mouse antibody was successfully established. The antibodies generated in this study may have the potential for use in alternative antibody therapies for HBV infection.
• Inhibitory effect of a novel thiazolidinedione derivative on hepatitis B virus entry.
  Tomohisa Tanaka; Kaori Okuyama-Dobashi; Ryoji Motohashi; Hiromasa Yokoe; Kazunori Takahashi; Pattama Wiriyasermkul; Hirotake Kasai; Atsuya Yamashita; Shinya Maekawa; Nobuyuki Enomoto; Akihide Ryo; Shushi Nagamori; Masayoshi Tsubuki; Kohji Moriishi
  Antiviral research, 194, 105165, 105165, 2021年08月19日, ［国際誌］
  英語, 研究論文（学術雑誌）, The development of novel antivirals to treat hepatitis B virus (HBV) infection is still needed because currently available drugs do not completely eradicate chronic HBV in some patients. Recently, troglitazone and ciglitazone, classified among the compounds including the thiazolidinedione (TZD) moiety, were found to inhibit HBV infection, but these compounds are not clinically available. In this study, we synthesized 11 TZD derivatives, compounds 1-11, and examined the effect of each compound on HBV infection in HepG2 cells expressing NTCP (HepG2/NTCP cells). Among the derivatives, (Z)-5-((4'-(naphthalen-1-yl)-[1,1'-biphenyl]-4-yl)methylene)thiazolidine-2,4-dione (compound 6) showed the highest antiviral activity, with an IC50 value of 0.3 μM and a selectivity index (SI) of 85, but compound 6 did not affect HCV infection. Treatment with compound 6 inhibited HBV infection in primary human hepatocytes (PHHs) but did not inhibit viral replication in HepG2.2.15 cells or HBV DNA-transfected Huh7 cells. Moreover, treatment with compound 6 significantly impaired hepatitis delta virus (HDV) infection and inhibited a step in HBV particle internalization but did not inhibit attachment of the preS1 lipopeptide or viral particles to the cell surface. These findings suggest that compound 6 interferes with HBV infection via inhibition of the internalization process.
• DsRNA Sequencing for RNA Virus Surveillance Using Human Clinical Samples.
  Takuma Izumi; Yuhei Morioka; Syun-Ichi Urayama; Daisuke Motooka; Tomokazu Tamura; Takahiro Kawagishi; Yuta Kanai; Takeshi Kobayashi; Chikako Ono; Akinari Morinaga; Takahiro Tomiyama; Norifumi Iseda; Yukiko Kosai; Shoichi Inokuchi; Shota Nakamura; Tomohisa Tanaka; Kohji Moriishi; Hiroaki Kariwa; Tomoharu Yoshizumi; Masaki Mori; Yoshiharu Matsuura; Takasuke Fukuhara
  Viruses, 13, 7, 2021年07月06日, ［国際誌］
  英語, 研究論文（学術雑誌）, Although viruses infect various organs and are associated with diseases, there may be many unidentified pathogenic viruses. The recent development of next-generation sequencing technologies has facilitated the establishment of an environmental viral metagenomic approach targeting the intracellular viral genome. However, an efficient method for the detection of a viral genome derived from an RNA virus in animal or human samples has not been established. Here, we established a method for the efficient detection of RNA viruses in human clinical samples. We then tested the efficiency of the method compared to other conventional methods by using tissue samples collected from 57 recipients of living donor liver transplantations performed between June 2017 and February 2019 at Kyushu University Hospital. The viral read ratio in human clinical samples was higher by the new method than by the other conventional methods. In addition, the new method correctly identified viral RNA from liver tissues infected with hepatitis C virus. This new technique will be an effective tool for intracellular RNA virus surveillance in human clinical samples and may be useful for the detection of new RNA viruses associated with diseases.
• Induction of HOX Genes by Hepatitis C Virus Infection via Impairment of Histone H2A Monoubiquitination
  Hirotake Kasai; Kazuki Mochizuki; Tomohisa Tanaka; Atsuya Yamashita; Yoshiharu Matsuura; Kohji Moriishi
  JOURNAL OF VIROLOGY, 95, 6, 2021年02月24日, ［査読有り］, ［国際誌］
  英語, 研究論文（学術雑誌）, Hepatitis C virus (HCV) infection causes liver pathologies, including hepatocellular carcinoma (HCC). Homeobox (HOX) gene products regulate embryonic development and are associated with tumorigenesis, although the regulation of HOX genes by HCV infection has not been clarified in detail. We examined the effect of HCV infection on HOX gene expression. In this study, HCV infection induced more than half of the HOX genes and reduced the level of histone H2A monoubiquitination on lysine 119 (K119) (H2Aub), which represses HOX gene promoter activity. HCV infection also promoted proteasome-dependent degradation of RNF2, which is an E3 ligase mediating H2A monoubiquitination as a component of polycomb repressive complex 1. Since full-genomic replicon cells but not subgenomic replicon cells exhibited reduced RNF2 and H2Aub levels and induction of HOX genes, we focused on the core protein. Expression of the core protein reduced the amounts of RNF2 and H2Aub and induced HOX genes. Treatment with LY-411575, which can reduce HCV core protein expression via signal peptide peptidase (SPP) inhibition without affecting other viral proteins, dose-dependently restored the amounts of RNF2 and H2Aub in HCV-infected cells and impaired the induction of HOX genes and production of viral particles but not viral replication. The chromatin immunoprecipitation assay results also indicated infection- and proteasome-dependent reductions in H2Aub located in HOX gene promoters. These results suggest that HCV infection or core protein induces HOX genes by impairing histone H2A monoubiquitination via a reduction in the RNF2 level.IMPORTANCE Recently sustained virologic response can be achieved by direct-acting antiviral (DAA) therapy in most hepatitis C patients. Unfortunately, DAA therapy does not completely eliminate a risk of hepatocellular carcinoma (HCC). Several epigenetic factors, including histone modifications, are well known to contribute to hepatitis C virus (HCV)-associated HCC. However, the regulation of histone modifications by HCV infection has not been clarified in detail. In this study, our data suggest that HCV infection or HCV core protein expression impairs monoubiquitination of histone H2A K119 in the homeobox (HOX) gene promoter via destabilization of RNF2 and then induces HOX genes. Several lines of evidence suggest that the expression of several HOX genes is dysregulated in certain types of tumors. These findings reveal a novel mechanism of HCV-related histone modification and may provide information about new targets for diagnosis and prevention of HCC occurrence.
• N-Terminal PreS1 Sequence Regulates Efficient Infection of Cell-Culture-Generated Hepatitis B Virus
  Asako Murayama; Norie Yamada; Yoshiki Osaki; Masaaki Shiina; Hussein Hassan Aly; Masashi Iwamoto; Senko Tsukuda; Koichi Watashi; Mami Matsuda; Ryosuke Suzuki; Tomohisa Tanaka; Kohji Moriishi; Tetsuro Suzuki; Hironori Nishitsuji; Masaya Sugiyama; Masashi Mizokami; Kunitada Shimotohno; Takaji Wakita; Masamichi Muramatsu; T Jake Liang; Takanobu Kato
  HEPATOLOGY, 73, 2, 520, 532, 2021年02月, ［査読有り］, ［国際誌］
  英語, 研究論文（学術雑誌）, BACKGROUND AND AIMS: An efficient cell-culture system for hepatitis B virus (HBV) is indispensable for research on viral characteristics and antiviral reagents. Currently, for the HBV infection assay in cell culture, viruses derived from HBV genome-integrated cell lines of HepG2.2.15 or HepAD-38 are commonly used. However, these viruses are not suitable for the evaluation of polymorphism-dependent viral characteristics or resistant mutations against antiviral reagents. HBV obtained by the transient transfection of the ordinary HBV molecular clone has limited infection efficiencies in cell culture. APPROACH AND RESULTS: We found that an 11-amino-acid deletion (d11) in the preS1 region enhances the infectivity of cell-culture-generated HBV (HBVcc) to sodium taurocholate cotransporting polypeptide-transduced HepG2 (HepG2/NTCP) cells. Infection of HBVcc derived from a d11-introduced genotype C strain (GTC-d11) was ~10-fold more efficient than infection of wild-type GTC (GTC-wt), and the number of infected cells was comparable between GTC-d11- and HepG2.2.15-derived viruses when inoculated with the same genome equivalents. A time-dependent increase in pregenomic RNA and efficient synthesis of covalently closed circular DNA were detected after infection with the GTC-d11 virus. The involvement of d11 in the HBV large surface protein in the enhanced infectivity was confirmed by an HBV reporter virus and hepatitis D virus infection system. The binding step of the GTC-d11 virus onto the cell surface was responsible for this efficient infection. CONCLUSIONS: This system provides a powerful tool for studying the infection and propagation of HBV in cell culture and also for developing the antiviral strategy against HBV infection.
• Amino Acid Polymorphism in Hepatitis B Virus Associated With Functional Cure.
  Takashi Honda; Norie Yamada; Asako Murayama; Masaaki Shiina; Hussein Hassan Aly; Asuka Kato; Takanori Ito; Yoji Ishizu; Teiji Kuzuya; Masatoshi Ishigami; Yoshiki Murakami; Tomohisa Tanaka; Kohji Moriishi; Hironori Nishitsuji; Kunitada Shimotohno; Tetsuya Ishikawa; Mitsuhiro Fujishiro; Masamichi Muramatsu; Takaji Wakita; Takanobu Kato
  Cellular and molecular gastroenterology and hepatology, 12, 5, 1583, 1598, 2021年, ［国際誌］
  英語, 研究論文（学術雑誌）, BACKGROUND & AIMS: To provide an adequate treatment strategy for chronic hepatitis B, it is essential to know which patients are expected to have a good prognosis and which patients do not require therapeutic intervention. Previously, we identified the substitution of isoleucine to leucine at amino acid 97 (I97L) in the hepatitis B core region as a key predictor among patients with stable hepatitis. In this study, we attempted to identify the point at which I97L affects the hepatitis B virus (HBV) life cycle and to elucidate the underlying mechanisms governing the stabilization of hepatitis. METHODS: To confirm the clinical features of I97L, we used a cohort of hepatitis B e antigen-negative patients with chronic hepatitis B infected with HBV-I97 wild-type (wt) or HBV-I97L. The effects of I97L on viral characteristics were evaluated by in vitro HBV production and infection systems with the HBV reporter virus and cell culture-generated HBV. RESULTS: The ratios of reduction in hepatitis B surface antigen and HBV DNA were higher in patients with HBV-I97L than in those with HBV-I97wt. HBV-I97L exhibited lower infectivity than HBV-I97wt in both infection systems with reporter HBV and cell culture-generated HBV. HBV-I97L virions exhibiting low infectivity primarily contained a single-stranded HBV genome. The lower efficiency of cccDNA synthesis was demonstrated after infection of HBV-I97L or transfection of the molecular clone of HBV-I97L. CONCLUSIONS: The I97L substitution reduces the level of cccDNA through the generation of immature virions with single-stranded genomes. This I97L-associated low efficiency of cccDNA synthesis may be involved in the stabilization of hepatitis.
• Establishment of a cell culture model permissive for infection by hepatitis B and C viruses.
  Teruhime Otoguro; Tomohisa Tanaka; Hirotake Kasai; Nobuhiro Kobayashi; Atsuya Yamashita; Takasuke Fukuhara; Akihide Ryo; Moto Fukai; Akinobu Taketomi; Yoshiharu Matsuura; Kohji Moriishi
  Hepatology communications, 5, 4, 634, 649, 2020年12月19日, ［査読有り］, ［国際誌］
  英語, 研究論文（学術雑誌）, Compared with each monoinfection, coinfection with hepatitis B virus (HBV) and hepatitis C virus (HCV) is well known to increase the risks of developing liver cirrhosis and hepatocellular carcinoma. However, the mechanism by which HBV/HCV coinfection is established in hepatocytes is not well understood. Common cell culture models for coinfection are required to examine viral propagation. In this study, we aimed to establish a cell line permissive for both HBV and HCV infection. We first prepared a HepG2 cell line expressing sodium taurocholate cotransporting polypeptide, an HBV receptor, and then selected a cell line highly permissive for HBV infection, G2/NT18-B. After transduction with a lentivirus-encoding microRNA-122, the cell line harboring the highest level of replicon RNA was selected and then treated with anti-HCV compounds to eliminate the replicon RNA. The resulting cured cell line was transduced with a plasmid-encoding CD81. The cell line permissive for HCV infection was cloned and then designated the G2BC-C2 cell line, which exhibited permissiveness for HBV and HCV propagation. JAK inhibitor I potentiated the HCV superinfection of HBV-infected cells, and fluorescence-activated cell-sorting analysis indicated that HBV/HCV double-positive cells accounted for approximately 30% of the coinfected cells. Among several host genes tested, cyclooxygenase-2 showed synergistic induction by coinfection compared with each monoinfection. Conclusion: These data indicate that our in vitro HBV/HCV coinfection system provides an easy-to-use platform for the study of host and viral responses against coinfection and the development of antiviral agents targeting HBV and HCV.
• Identification of Two Critical Neutralizing Epitopes in the Receptor Binding Domain of Hepatitis B Virus preS1
  Keigo Yato; Taishi Onodera; Mami Matsuda; Saya Moriyama; Akira Fujimoto; Koichi Watashi; Hideki Aizaki; Tomohisa Tanaka; Kohji Moriishi; Hironori Nishitsuji; Kunitada Shimotohno; Koji Tamura; Yoshimasa Takahashi; Takaji Wakita; Masamichi Muramatsu; Takanobu Kato; Ryosuke Suzuki
  JOURNAL OF VIROLOGY, 2020年12月09日, ［査読有り］, ［国際誌］
  英語, 研究論文（学術雑誌）, Hepatitis B virus (HBV) infection is a major public health problem. Human hepatocytes are infected with HBV via binding between the preS1 region in the large envelope protein of HBV and sodium taurocholate cotransporting polypeptide. Although several monoclonal antibodies (MAbs) that recognize the receptor binding domain in preS1 and neutralize HBV infection have been isolated, details of neutralizing epitopes are not understood. In this study, we generated 13 MAbs targeting the preS1 receptor binding domain from preS1-specific memory B cells derived from DNA immunized mice. The MAbs were classified into three groups according to the epitope regions, designated epitopes I-III. A virus neutralization assay revealed that MAbs recognizing epitopes I and III neutralized HBV infection, suggesting that these domains are critical epitopes for viral neutralization. In addition, a neutralization assay against multiple genotypes of HBV revealed that epitope I is a semi-pangenotypic neutralizing epitope, whereas epitope III is a genotype-specific epitope. We also showed that neutralizing MAbs against preS1 could neutralize HBV bearing vaccine-induced escape mutation. These findings provide insight into novel immunoprophylaxis for the prevention and treatment of HBV infection.IMPORTANCE The HBV preS1 2-47 aa region (preS1/2-47) is essential for virus binding with sodium taurocholate cotransporting polypeptide. Several MAbs targeting preS1/2-47 have been reported to neutralize HBV infection; however, which region in preS1/2-47 contains the critical neutralizing epitope for HBV infection is unclear. Here, we generated several MAbs targeting preS1/2-47 and found that MAbs recognizing the N- or C-terminus of preS1/2-47 remarkably neutralized HBV infection. We further confirmed the neutralizing activity of anti-preS1 MAbs against HBV with vaccine escape mutation. These data clarified the relationship between the antibody epitope and the virus neutralizing activity and also suggested the potential ability of a vaccine antigen containing the preS1 region to overcome the weakness of current HB vaccines comprising the small S protein.
• USP15 Participates in Hepatitis C Virus Propagation through Regulation of Viral RNA Translation and Lipid Droplet Formation.
  Shinji Kusakabe; Tatsuya Suzuki; Yukari Sugiyama; Saori Haga; Kanako Horike; Makoto Tokunaga; Junki Hirano; He Zhang; David Virya Chen; Hanako Ishiga; Yasumasa Komoda; Chikako Ono; Takasuke Fukuhara; Masahiro Yamamoto; Masahito Ikawa; Takashi Satoh; Shizuo Akira; Tomohisa Tanaka; Kohji Moriishi; Moto Fukai; Akinobu Taketomi; Sachiyo Yoshio; Tatsuya Kanto; Tetsuro Suzuki; Toru Okamoto; Yoshiharu Matsuura
  Journal of virology, 93, 6, 2019年03月15日, ［査読有り］, ［国際誌］
  英語, 研究論文（学術雑誌）, Hepatitis C virus (HCV) utilizes cellular factors for efficient propagation. Ubiquitin is covalently conjugated to the substrate to alter its stability or to modulate signal transduction. In this study, we examined the importance of ubiquitination for HCV propagation. We found that inhibition of deubiquitinating enzymes (DUBs) or overexpression of nonspecific DUBs impaired HCV replication, suggesting that ubiquitination regulates HCV replication. To identify specific DUBs involved in HCV propagation, we set up RNA interference (RNAi) screening against DUBs and successfully identified ubiquitin-specific protease 15 (USP15) as a novel host factor for HCV propagation. Our studies showed that USP15 is involved in translation of HCV RNA and production of infectious HCV particles. In addition, deficiency of USP15 in human hepatic cell lines (Huh7 and Hep3B/miR-122 cells) but not in a nonhepatic cell line (293T cells) impaired HCV propagation, suggesting that USP15 participates in HCV propagation through the regulation of hepatocyte-specific functions. Moreover, we showed that loss of USP15 had no effect on innate immune responses in vitro and in vivo We also found that USP15-deficient Huh7 cells showed reductions in the amounts of lipid droplets (LDs), and the addition of palmitic acids restored the production of infectious HCV particles. Taken together, these data suggest that USP15 participates in HCV propagation by regulating the translation of HCV RNA and the formation of LDs.IMPORTANCE Although ubiquitination has been shown to play important roles in the HCV life cycle, the roles of deubiquitinating enzymes (DUBs), which cleave ubiquitin chains from their substrates, in HCV propagation have not been investigated. Here, we identified USP15 as a DUB regulating HCV propagation. USP15 showed no interaction with viral proteins and no participation in innate immune responses. Deficiency of USP15 in Huh7 cells resulted in suppression of the translation of HCV RNA and reduction in the amounts of lipid droplets, and the addition of fatty acids partially restored the production of infectious HCV particles. These data suggest that USP15 participates in HCV propagation in hepatic cells through the regulation of viral RNA translation and lipid metabolism.
• Roles of the 5' untranslated region of nonprimate hepacivirus in translation initiation and viral replication
  Tomohisa Tanaka; Teruhime Otoguro; Atsuya Yamashita; Hirotake Kasai; Takasuke Fukuhara; Yoshiharu Matsuura; Kohji Moriishi
  Journal of Virology, 92, 7, American Society for Microbiology, 2018年04月01日, ［査読有り］, ［国際誌］
  英語, 研究論文（学術雑誌）
• Seroepidemiology of non-primate hepacivirus (NPHV) in japanese native horses
  Shizuka Hayashi; Tomohisa Tanaka; Kohji Moriishi; Kazuhiro Hirayama; Akio Yamada; Kozue Hotta
  Journal of Veterinary Medical Science, 80, 1, 186, 189, Japanese Society of Veterinary Science, 2018年, ［査読有り］, ［国内誌］
  英語, 研究論文（学術雑誌）
• Seroepidemiology of non-primate hepacivirus (NPHV) in japanese native horses
  Shizuka Hayashi; Tomohisa Tanaka; Kohji Moriishi; Kazuhiro Hirayama; Akio Yamada; Kozue Hotta
  Journal of Veterinary Medical Science, 80, 1, 186, 189, Japanese Society of Veterinary Science, 2018年, ［査読有り］
  英語, 研究論文（学術雑誌）
• Inhibitory effects of metachromin A on hepatitis B virus production via impairment of the viral promoter activity
  Atsuya Yamashita; Mayumi Tamaki; Hirotake Kasai; Tomohisa Tanaka; Teruhime Otoguro; Akihide Ryo; Shinya Maekawa; Nobuyuki Enomoto; Nicole J. de Voogd; Junichi Tanaka; Kohji Moriishi
  ANTIVIRAL RESEARCH, 145, 136, 145, 2017年09月, ［査読有り］, ［国際誌］
  英語, 研究論文（学術雑誌）
• Cinnamic acid derivatives inhibit hepatitis C virus replication via the induction of oxidative stress
  Ryota Amano; Atsuya Yamashita; Hirotake Kasai; Tomoka Hori; Sayoko Miyasato; Setsu Saito; Hiromasa Yokoe; Kazunori Takahashi; Tomohisa Tanaka; Teruhime Otoguro; Shinya Maekawa; Nobuyuki Enomoto; Masayoshi Tsubuki; Kohji Moriishi
  ANTIVIRAL RESEARCH, 145, 123, 130, 2017年09月, ［査読有り］, ［国際誌］
  英語, 研究論文（学術雑誌）
• Hepatitis B virus prevents excessive viral production via reduction of cell death-inducing DFF45-like effectors
  Jun Yasumoto; Hirotake Kasai; Kentaro Yoshimura; Teruhime Otoguro; Koichi Watashi; Takaji Wakita; Atsuya Yamashita; Tomohisa Tanaka; Sen Takeda; Kohji Moriishi
  JOURNAL OF GENERAL VIROLOGY, 98, 7, 1762, 1773, 2017年07月, ［査読有り］, ［国際誌］
  英語, 研究論文（学術雑誌）
• Inhibitory effect of presenilin inhibitor LY411575 on maturation of hepatitis C virus core protein, production of the viral particle and expression of host proteins involved in pathogenicity
  Teruhime Otoguro; Tomohisa Tanaka; Hirotake Kasai; Atsuya Yamashita; Kohji Moriishi
  MICROBIOLOGY AND IMMUNOLOGY, 60, 11, 740, 753, 2016年11月, ［査読有り］, ［国際誌］
  英語, 研究論文（学術雑誌）
• CDK9 inhibitor FIT-039 suppresses HBV propagation
  Kohji Moriishi; Tomohisa Tanaka; Kaori Okuyama-obashi; Wenjia Chen; Toru Okamoto; Keiji Ueda; Takamitsu Hosoya; Yoshiharu Matsuura; Akihide Ryo; Yasuhito Tanaka; Masatoshi Hagiwara
  2016年10月, ［査読有り］
  英語, 研究論文（その他学術会議資料等）
• Inhibitory effect of CDK9 inhibitor FIT-039 on hepatitis B virus propagation
  Tomohisa Tanaka; Kaori Okuyama-Dobashi; Shuko Murakami; Wenjia Chen; Toru Okamoto; Keiji Ueda; Takamitsu Hosoya; Yoshiharu Matsuura; Akihide Ryo; Yasuhito Tanaka; Masatoshi Hagiwara; Kohji Moriishi
  ANTIVIRAL RESEARCH, 133, 156, 164, 2016年09月, ［査読有り］, ［国際誌］
  英語, 研究論文（学術雑誌）
• Hepatitis B virus efficiently infects non-adherent hepatoma cells via human sodium taurocholate cotransporting polypeptide
  Kaori Okuyama-Dobashi; Hirotake Kasai; Tomohisa Tanaka; Atsuya Yamashita; Jun Yasumoto; Wenjia Chen; Toru Okamoto; Shinya Maekawa; Koichi Watashi; Takaji Wakita; Akihide Ryo; Tetsuro Suzuki; Yoshiharu Matsuura; Nobuyuki Enomoto; Kohji Moriishi
  SCIENTIFIC REPORTS, 5, 17047, 17047, 2015年11月, ［査読有り］, ［国際誌］
  英語, 研究論文（学術雑誌）
• Involvement of FKBP6 in hepatitis C virus replication
  Hirotake Kasai; Kunihiro Kawakami; Hiromasa Yokoe; Kentaro Yoshimura; Masanori Matsuda; Jun Yasumoto; Shinya Maekawa; Atsuya Yamashita; Tomohisa Tanaka; Masanori Ikeda; Nobuyuki Kato; Toru Okamoto; Yoshiharu Matsuura; Naoya Sakamoto; Nobuyuki Enomoto; Sen Takeda; Hideki Fujii; Masayoshi Tsubuki; Masami Kusunoki; Kohji Moriishi
  SCIENTIFIC REPORTS, 5, 16699, 16699, 2015年11月, ［査読有り］, ［国際誌］
  英語, 研究論文（学術雑誌）
• Identification of Antiviral Agents Targeting Hepatitis B Virus Promoter from Extracts of Indonesian Marine Organisms by a Novel Cell-Based Screening Assay
  Atsuya Yamashita; Yuusuke Fujimoto; Mayumi Tamaki; Andi Setiawan; Tomohisa Tanaka; Kaori Okuyama-Dobashi; Hirotake Kasai; Koichi Watashi; Takaji Wakita; Masaaki Toyama; Masanori Baba; Nicole J. de Voogd; Shinya Maekawa; Nobuyuki Enomoto; Junichi Tanaka; Kohji Moriishi
  MARINE DRUGS, 13, 11, 6759, 6773, 2015年11月, ［査読有り］, ［国際誌］
  英語, 研究論文（学術雑誌）
• トリプシン・EDTAによるNTCP依存HBV感染の増強
  土橋香織; 葛西宏威; 田中智久; 陳文家; 渡士幸一; 脇田隆字; 山下篤哉; 梁明秀; 岡本徹; 松浦善治; 森石恆司
  2014年11月, ［査読有り］
  日本語, 研究論文（その他学術会議資料等）
• Hallmarks of Hepatitis C Virus in Equine Hepacivirus
  Tomohisa Tanaka; Hirotake Kasai; Atsuya Yamashita; Kaori Okuyama-Dobashi; Jun Yasumoto; Shinya Maekawa; Nobuyuki Enomoto; Toru Okamoto; Yoshiharu Matsuura; Masami Morimatsu; Noboru Manabe; Kazuhiko Ochiai; Kazuto Yamashita; Kohji Moriishi
  JOURNAL OF VIROLOGY, 88, 22, 13352, 13366, 2014年11月, ［査読有り］, ［国際誌］
  英語, 研究論文（学術雑誌）
• Inhibitory Effects of Caffeic Acid Phenethyl Ester Derivatives on Replication of Hepatitis C Virus
  Hui Shen; Atsuya Yamashita; Masamichi Nakakoshi; Hiromasa Yokoe; Masashi Sudo; Hirotake Kasai; Tomohisa Tanaka; Yuusuke Fujimoto; Masanori Ikeda; Nobuyuki Kato; Naoya Sakamoto; Hiroko Shindo; Shinya Maekawa; Nobuyuki Enomoto; Masayoshi Tsubuki; Kohji Moriishi
  PLOS ONE, 8, 12, e82299, 2013年12月, ［査読有り］, ［国際誌］
  英語, 研究論文（学術雑誌）
• Excessive Cytokine Response to Rapid Proliferation of Highly Pathogenic Avian Influenza Viruses Leads to Fatal Systemic Capillary Leakage in Chickens
  Saya Kuribayashi; Yoshihiro Sakoda; Takeshi Kawasaki; Tomohisa Tanaka; Naoki Yamamoto; Masatoshi Okamatsu; Norikazu Isoda; Yoshimi Tsuda; Yuji Sunden; Takashi Umemura; Noriko Nakajima; Hideki Hasegawa; Hiroshi Kida
  PLOS ONE, 8, 7, e68375, 2013年07月, ［査読有り］, ［国際誌］
  英語, 研究論文（学術雑誌）
• Severe Acute Respiratory Syndrome Coronavirus nsp1 Facilitates Efficient Propagation in Cells through a Specific Translational Shutoff of Host mRNA
  Tomohisa Tanaka; Wataru Kamitani; Marta L. DeDiego; Luis Enjuanes; Yoshiharu Matsuura
  JOURNAL OF VIROLOGY, 86, 20, 11128, 11137, 2012年10月, ［査読有り］, ［国際誌］
  英語, 研究論文（学術雑誌）
• Recovery of Leptospires from Miniature Pigs Experimentally Infected with Leptospira interrogans Serovar Manilae Strain UP-MMC under Immunosuppressive Conditions by Dexamethasone
  Yoshihiro Sakoda; Michiko Naito; Mutsumi Ito; Yuki Ito; Norikazu Isoda; Tomohisa Tanaka; Takashi Umemura; Hiroshi Kida
  JOURNAL OF VETERINARY MEDICAL SCIENCE, 74, 7, 955, 958, 2012年07月, ［査読有り］, ［国内誌］
  英語, 研究論文（学術雑誌）
• Antigenic, genetic, and pathogenic characterization of H5N1 highly pathogenic avian influenza viruses isolated from dead whooper swans (Cygnus cygnus) found in northern Japan in 2008
  Masatoshi Okamatsu; Tomohisa Tanaka; Naoki Yamamoto; Yoshihiro Sakoda; Takashi Sasaki; Yoshimi Tsuda; Norikazu Isoda; Norihide Kokumai; Ayato Takada; Takashi Umemura; Hiroshi Kida
  VIRUS GENES, 41, 3, 351, 357, 2010年12月, ［査読有り］, ［国際誌］
  英語, 研究論文（学術雑誌）
• Lipopolysaccharide treatment and inoculation of influenza A virus results in influenza virus-associated encephalopathy-like changes in neonatal mice
  Tomohisa Tanaka; Yuji Sunden; Yoshihiro Sakoda; Hiroshi Kida; Kenji Ochiai; Takashi Umemura
  JOURNAL OF NEUROVIROLOGY, 16, 2, 125, 132, 2010年04月, ［査読有り］, ［国際誌］
  英語, 研究論文（学術雑誌）
• Glycosylation of the West Nile Virus Envelope Protein Increases In Vivo and In Vitro Viral Multiplication in Birds
  Ryo Murata; Yuki Eshita; Akihiko Maeda; Junko Maeda; Saki Akita; Tomohisa Tanaka; Kentaro Yoshii; Hiroaki Kariwa; Takashi Umemura; Ikuo Takashima
  AMERICAN JOURNAL OF TROPICAL MEDICINE AND HYGIENE, 82, 4, 696, 704, 2010年04月, ［査読有り］, ［国際誌］
  英語, 研究論文（学術雑誌）
• Chemical deicer poisoning was suspected as a cause of the 2005-2006 wintertime mortality of small wild birds in Hokkaido
  Tomohisa Tanaka; Ginpei Tanoue; Masahiro Yamasaki; Ikuo Takashima; Yoshihiro Sakoda; Kenji Ochiai; Takashi Umemura
  JOURNAL OF VETERINARY MEDICAL SCIENCE, 70, 6, 607, 610, 2008年06月, ［査読有り］, ［国内誌］
  英語, 研究論文（学術雑誌）
• Efficacy of intracerebral immunization against pseudorabies virus in mice
  Jae-Ho Shin; Yoshihiro Sakoda; Jae Hoon Kim; Tomohisa Tanaka; Hiroshi Kida; Takashi Kimura; Kenji Ochiai; Takashi Umemura
  MICROBIOLOGY AND IMMUNOLOGY, 50, 10, 823, 830, 2006年, ［査読有り］, ［国際誌］
  英語, 研究論文（学術雑誌）
• Efficacy of intracerebral immunization against pseudorabies virus in mice
  Jae-Ho Shin; Yoshihiro Sakoda; Hoon Kim Jae; Tomohisa Tanaka; Hiroshi Kida; Takashi Kimura; Kenji Ochiai; Takashi Umemura
  Microbiology and Immunology, 50, 10, 823, 830, Center for Academic Publications Japan, 2006年, ［査読有り］
  英語, 研究論文（学術雑誌）

• B型肝炎ウイルスpreS2領域に対する抗体はウイルス感染を抑制する
  矢藤慶悟; 矢藤慶悟; 深野顕人; 松田麻未; 田中智久; 森石恆司; 西辻裕紀; 下遠野邦忠; 田村浩二; 加藤孝宣; 村松正道; 鈴木亮介; 鈴木亮介, 日本ウイルス学会学術集会プログラム・予稿集(Web), 68th, 2021年
• Probe Electrospray Ionization質量分析法(PESI-MS)を用いたHCV感染細胞内脂質組成の解析
  葛西宏威; 吉村健太郎; 安本順; 山下篤哉; 田中智久; 竹田扇; 森石恆司, 日本ウイルス学会学術集会プログラム・抄録集, 61st, 2013年
• 2008年北海道で発見された斃死オオハクチョウから分離したH5N1高病原性鳥インフルエンザウイルスの性状
  岡松正敏; 迫田義博; 吉田裕美; 田中智久; 津田祥美; 磯田典和; 中山絵里; 苫米地大輔; 松野啓太; 梅村孝司; 高田礼人; 喜田宏, 日本ウイルス学会学術集会プログラム・抄録集, 56th, 263, 2008年10月01日
  日本語
• 2008年北海道で発見された斃死オオハクチョウから分離したH5N1高病原性鳥インフルエンザウイルスの性状
  岡松正敏; 迫田義博; 吉田裕美; 田中智久; 津田祥美; 磯田典和; 中山絵里; 苫米地大輔; 松野啓太; 梅村孝司; 高田礼人; 喜田宏, 日本獣医学会学術集会講演要旨集, 146th, 193, 2008年09月05日
  日本語
• Efficacy of intracerebral vaccination against pseudorabies virus in mice
  Jae-Ho Shin; Yoshihiro Sakoda; Jae Hoon Kim; Tomohisa Tanaka; Hiroshi Kida; Takashi Kimura; Kenji Ochiai; Takashi Umemura, JOURNAL OF NEUROIMMUNOLOGY, 178, 114, 114, 2006年09月
  英語, 研究発表ペーパー・要旨（国際会議）

• HBV Enhancer I-X promoterをターゲットとした抗HBV化合物の同定
  山下 篤哉; 田中 智久; 葛西 宏威; 森石 恆司
  第68回日本ウイルス学会学術集会, 2021年11月16日, 日本ウイルス学会, 日本語, 口頭発表（一般）
  ［国内会議］
• HCV感染によるポリコーム抑制複合体1活性制御の分子機序
  葛西 宏威; 山下 篤哉; 田中 智久; 赤池 康範; 大津 直樹; 森石 恆司
  第68回日本ウイルス学会学術集会, 2021年11月16日, 日本ウイルス学会, 日本語, 口頭発表（一般）
  ［国内会議］
• ラットヘパシウイルスの異種間伝播とマウス適応化
  大津 直樹; 田中 智久; 山下 篤哉; 葛西 宏威; 赤池 康範; 森石 恆司
  第68回日本ウイルス学会学術集会, 2021年11月16日, 日本ウイルス学会, 日本語, 口頭発表（一般）
  ［国内会議］
• 一過性および安定発現系への適用可能なSARS-CoV-2レプリコンシステムの開発
  田中 智久; 岡本 徹; 葛西 宏威; 山下 篤哉; 森石 恆司
  第68回日本ウイルス学会学術集会, 2021年11月16日, 日本ウイルス学会, 日本語, 口頭発表（一般）
  ［国内会議］
• B型肝炎ウイルスpreS2領域に対する抗体はウイルス感染を抑制する
  矢藤 慶悟; 深野 顕人; 松田 麻未; 田中 智久; 森石 恆司; 西辻 裕紀; 下遠野邦忠; 田村 浩二; 加藤 孝宣; 村松 正道; 鈴木 亮介
  第68回日本ウイルス学会学術集会, 2021年11月16日, 日本ウイルス学会, 日本語, ポスター発表
  ［国内会議］
• HBV感染に関与する cyclin-dependent kinaseの解析
  田中智久; 乙黒光姫; 葛西宏威; 山下篤哉; 福原崇介; 松浦善治; 森石恆司
  第67回日本ウイルス学会学術集会, 2019年10月29日, 英語, 口頭発表（一般）
  東京都, ［国内会議］
• B型および C型肝炎ウイルス感染を許容する培養細胞の樹立
  乙黒光姫; 田中智久; 葛西宏威; 山下篤哉; 福原崇介; 松浦善治; 森石恆司
  第67回日本ウイルス学会学術集会, 2019年10月29日, 英語, 口頭発表（一般）
  東京都, ［国内会議］
• HBV core promoter をターゲットとした新規抗HBV化合物4,4'-bis(cyclohexylmethyl)biphenyl-2,2',5,5'-tetraol
  山下篤哉; 田中智久; 乙黒光姫; 葛西宏威; 森石恆司
  第67回日本ウイルス学会学術集会, 2019年10月29日, 日本語, ポスター発表
  東京都, ［国内会議］
• C型肝炎ウイルス感染の宿主リン脂質構成への影 響
  葛西宏威; 田中智久; 山下篤哉; 乙黒光姫; 森石恆司
  第67回日本ウイルス学会学術集会, 2019年10月29日, 日本語, ポスター発表
  ［国内会議］
• Involvement of a novel cyclin-dependent kinase in HBV infection
  Tomohisa Tanaka; Kohji Moriishi
  2019 International HBV Meeting, 2019年10月01日, 英語, ポスター発表
  Melbourne, Australia, ［国際会議］
• へパシウイルスの疫学調査とHCVサロゲートモデルへの応用
  田中智久
  第8回肝炎ウイルス研修会, 2019年09月12日, 日本語, 口頭発表（一般）
  東京都, ［国内会議］
• Identification of Hepacivirus F subspecies from Japanese rodents
  Tanaka T; Otoguro T; Kasai H; Yamashita A; Kariwa H; Moriishi K
  第66回日本ウイルス学会学術集会, 2018年10月28日, 英語, ポスター発表
  京都テルサ, ［国内会議］
• Inhibition of signal peptide peptidase restores monoubiquitination of histone H2A and impairs Hox gene expression in HCV-infected cells
  Kasai H; Tanaka T; Yamashita A; Otoguro T; Moriishi K
  The 66th Annual Meeting of the Japanese Society for Virology, 2018年10月28日, 英語, 口頭発表（一般）
  京都テルサ, ［国内会議］
• Berberine suppresses hepatitis B virus production via impairment of HBV core promoter activity
  Yamashita A; Tanaka T; Otoguro T; Kasai H; Moriishi K
  第66回日本ウイルス学会学術集会, 2018年10月28日, 英語, ポスター発表
  京都テルサ, ［国内会議］
• Identification of Hepacivirus F subspecies in Japan
  Tanaka T; Kriwa H; Moriishi K
  25th International Symposium on Hepatitis C Virus and Related Viruses, 2018年10月09日, 英語, ポスター発表
  Dublin, Ireland, ［国際会議］
• Identification of a cyclin-dependent kinase that facilitates HBV infection
  Tanaka T; Otoguro T; Kasai H; Yamashita A; Moriishi K
  2018 International HBV Meeting, 2018年10月04日, 英語, ポスター発表
  Taormina, Italy, ［国際会議］
• anti-HBV activity of CDK9 selective inhibitor FIT-039
  Tomohisa Tanaka
  5th JAPAN-TAIWAN-KOREA HBV Research Symposium 2017, 2017年04月, 英語, シンポジウム・ワークショップパネル（公募）
  National Institute of Infectious Diseases, Toyama-Branch, ［国際会議］
• Cross-species compatibility of hepacivirus 5’ untranslated region
  Tomohisa Tanaka; Teruhime Otoguro; Hirotake Kasai; Atsuya Yamashita; Kaori Okuyama-Dobashi; Kohji Moriishi
  日本ウイルス学会学術集会, 2016年10月, 英語, 口頭発表（一般）
  ［国内会議］

• ウイルス学会
• 獣医学会
• 分子生物学会

• 古代ウイルスゲノム解析で明らかにするヒトと病原体の歴史
  科学研究費助成事業
  2022年06月30日 - 2025年03月31日
  安達 登; 田中 智久; 神澤 秀明; 森石 恆司
  青森県尻労安部遺跡および北海道北黄金貝塚から出土した人骨から検出されたヒトB型肝炎ウイルス(HBV)の遺伝子(以下、SHTおよびKGN)は、全領域を通じて塩基配列の相同性が高く、共通の祖先を持つHBV遺伝子と考えられた。既知のHBVのジェノタイプの中で、SHTとKGNはともに全体として東南アジア型のHBV遺伝子(SEA)に最も近ことが分かった。SHTもKGNも少なくともCore領域はSEA由来であり、SHTはSEA由来のS領域の一部を持っている。SHTはこのS領域において、ジェノタイプJやジェノタイプC4に非常に近い。そして、SHTとKGNの縄文タイプ（縄文タイプ：preS1に33bpのインサートを持ちその他の配列は全体としてSEAと近い）を系統ネットワーク解析した結果、これらのHBVは早い時期（：後期更新世の間）にSEAから分岐した可能性が示唆された。この結果から、SHTとKGNの共通祖先は東南アジアに起源を持ち、SEAから分岐して日本列島に到達し、そこで分岐・拡散したと考えられた。SEAには存在しないpreS1領域での33bpのインサートがSHT、KGNにはあることからも、SHTとKGNの縄文型はしばらくの間単系統であり、その後SHTとKGNに分岐した可能性があることが分かった。今回の研究で、東アジアに到達した初期の人類のうち、縄文人の祖先集団の一部とヒマラヤの南下集団との間に強い関係があることが明らかとなった。この成果を、第77回日本人類学会大会にて発表した。
  日本学術振興会, 挑戦的研究(萌芽), 山梨大学, 22K19343
• プロテオミクスに基づく新規の抗肝炎ウイルス戦略
  科学研究費助成事業
  2015年04月01日 - 2018年03月31日
  森石 恆司; 山下 篤哉; 葛西 宏威; 田中 智久
  本研究の目的は、C型肝炎ウイルス（HCV）蛋白質およびB型肝炎ウイルス（HBV）に対して相互作用する宿主因子を同定し、抗ウイルス活性および抗肝がん化活性をもつ化合物を同定し、新規抗肝炎ウイルス療法開発を目指すことである。HCV複製および感染粒子形成に必須である宿主因子としてFKBP6、HM13を同定し、DM-CHX、桂皮酸誘導体などを抗ウイルス化合物および抗肝がん化化合物として同定した。また、HBV複製に重要な因子p-TEFbに対する阻害剤も同定し、抗ウイルス活性があることを示し、ウイルスゲノム排除の可能性も示した。この研究成果、今後の新規抗肝炎ウイルス化合物開発に貢献するものと思われる。
  日本学術振興会, 基盤研究(C), 山梨大学, 15K08493
• コロナウイルスによるmRNA分解機構の解明と病原性発現機序の解明
  科学研究費助成事業
  2013年04月01日 - 2015年03月31日
  田中 智久
  重症急性呼吸器症候群（SARS）コロナウイルスのnsp1タンパク質は、宿主mRNAの切断を引き起こすことにより宿主遺伝子発現を阻害するが、そのメカニズムは分かっていない。本研究課題では、nsp1タンパク質依存性RNA切断に関与する分子候補として、宿主mRNA品質管理機構の一つであるナンセンスRNA分解機構において中心的な働きを担っているUPF1タンパク質を同定した。これまで、ウイルスの生存戦略として宿主mRNA品質管理機構が利用されているという報告はなく、本成果はウイルスの病原性発現機構の解明のみならず、細胞生物学分野においても重要な知見となることが考えられる。
  日本学術振興会, 若手研究(B), 山梨大学, 25860338