Mechanism of hepatocyte injury via survival and death signaling induced by hepatitis viruses

肝炎病毒诱导的生存和死亡信号损伤肝细胞的机制

• 批准号: 13307019
• 负责人: OMATA Masao
• 金额: $ 33.53万
• 依托单位: The University of Tokyo
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (A)
• 财政年份: 2001
• 资助国家: 日本
• 起止时间: 2001 至 2004
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-13307019/
• 关键词: Hepatitis B virus; Hepatitis C virus; Hepatitis delta virus; Signal transduction; Apoptosis; Innate Immunity; Persistent infection; NF-κB; A型肝炎ウイルス; 線維化; TGF-β; インターフェロン; p53; cDNA array; シグナル伝導; NF-KB; Bcl-Xr; SRF

In this study, we aimed to clarify the mechanism of hepatocyte injury via survival and death signaling induced by hepatitis viruses. 1)Hepatitis C virus(HCV) core protein activated NF-κB-dependent signaling pathway through tumor necrosis factor receptor-associated factor. This function of HCV core protein may play an important role in the inflammatory reaction induced by this virus. In fact, HCV core protein activated also interteukin(IL)-8 promoter through NF-κB. Moreover, differences in the amino acid sequence of HCV core protein correlates with hepatitis activity through modulation of IL-8 induction in HCV infected patients. In addition, HCV core protein upregulated transforming growth factor(TGF)β-1 expression, suggesting a new paradigm for exacerbation of liver fibrosis by HCV infection. 2)HCV NS3 protein interacts directly with TBK1,and that this binding results in the inhibition of the association between TBK1 and IRF-3,a key transcriptional factor to produce interferon-b, which … More leads to the inhibition of IRF-3 activation. This might show the mechanisms in the inhbition of innate immune responses and in the persistence of HCV infection by NS3 protein. 3)HCV NS4A and NS4B proteins inhibited cellular protein synthesis by targeting the process of translation. HCV NS4A and NS4B proteins have an effect of translational inhbition. This novel function may be involved in HCV infection and help its survival in host cells. 4)HCV NS5A protein interacts with and partially sequestrates p53 and hTAFII32,a component of TFIID and an essential coactivator of p53, in the cytoplasm and suppresses p53-mediated transcriptional transactivation and apoptosis during HCV infection, which may contribute to the hepatocarcinogenesis of HCV infection. 5)Uncerstanding the function of hepatitis B virus(HBV) X protein(HBx) is fundamental to elucidating the underlying mechanisms of hepatitis and hepatocarcinogenesis caused by HBV infection. We identified heat shock protein 60(Hsp60) as a novel cellular target of HBx by the combination of affinity purification and mass spectrometry. Confocal laser microscopy demonstrated that HBx and Hsp60 colocalized in mitochondria. Furthermore, TUNEL revealed that the introduction of HspGO into cells facilitated HBx-induced apoptosis. These findings suggest the importance of the molecular chaperon protein Hsp60 to the function of HBV viral proteins. 6)Hepatitis delta virus(HDV) is a naturally occurring satellite of HBV. HBx, alone or with the large isoform of HDV antigens(LHDAg), synergistically activated the serum response element(SRE)-dependent pathway. HBx activated the transcriptional ability of Elk-1,whereas LHDAg activated the transcritional ability of serum response factor(SRF). Thus, HBx and LHDAg synergistically activated the SRE-dependent pathway. These results may help us understand clinical phenomena in patients coinfected with HBV and HDV. Less

在本研究中，我们旨在阐明肝炎病毒通过存活和死亡信号诱导肝细胞损伤的机制。1)丙型肝炎病毒核心蛋白通过肿瘤坏死因子受体相关因子激活NF-κB依赖的信号通路。丙型肝炎病毒核心蛋白的这一功能可能在该病毒引起的炎症反应中起重要作用。事实上，丙型肝炎病毒核心蛋白还通过核因子κB激活了IL-8启动子。此外，丙型肝炎病毒核心蛋白氨基酸序列的差异可能通过调节IL-8的诱导而影响肝炎的活动性。此外，丙型肝炎病毒核心蛋白上调转化生长因子β-1的表达，为丙型肝炎病毒感染加重肝纤维化提供了新的范例。2)丙型肝炎病毒NS3蛋白直接与Tbk1相互作用，这种结合导致抑制Tbk1和Irf-3之间的结合，Irf-3是产生干扰素-b的关键转录因子，…更多则导致抑制IRF-3的激活。这可能揭示了NS3蛋白抑制先天免疫反应和持续感染丙型肝炎病毒的机制。3)丙型肝炎病毒NS4A和NS4B蛋白通过靶向翻译过程抑制细胞蛋白质合成。丙型肝炎病毒NS4A和NS4B蛋白具有翻译抑制作用。这一新的功能可能参与了丙型肝炎病毒的感染，并帮助其在宿主细胞中存活。4)丙型肝炎病毒NS5A蛋白与TFIID组分、P53的重要辅活化子p53和hTAFII32相互作用并部分封闭在细胞质中，抑制P53介导的转录反式激活和细胞凋亡，这可能参与了丙型肝炎病毒感染的肝癌发生。5)了解乙肝病毒X蛋白(HBx)的功能是阐明乙肝病毒感染所致肝炎和肝癌发生机制的基础。我们通过亲和纯化和质谱分析相结合的方法，确定了热休克蛋白60(Hsp60)是HBx的一个新的细胞靶点。激光共聚焦显微镜显示HBx和Hsp60共定位于线粒体。此外，原位末端标记法显示，HspGO导入细胞可促进HBx诱导的细胞凋亡。这些发现提示分子伴侣蛋白Hsp60对乙肝病毒蛋白功能的重要性。6)丁型肝炎病毒(HDV)是一种天然存在的乙肝病毒卫星。HBx单独或与HDV大亚型抗原(LHDAg)协同激活依赖血清反应元件(SRE)的途径。HBx激活ELK-1转录能力，而LHDAg激活血清反应因子(SRF)转录能力。因此，HBx和LHDAg协同激活了SRE依赖的途径。这些结果有助于我们了解乙肝病毒和丁型肝炎病毒混合感染患者的临床现象。较少

项目成果

Acyclic retinoid inhibits human hepatoma cell growth by suppressing fibroblast growth factor-mediated signaling pathways

• DOI: 10.1053/j.gastro.2004.09.077
• 发表时间: 2005-01-01
• 期刊: GASTROENTEROLOGY
• 影响因子: 29.4
• 作者: Shao, RX;Otsuka, M;Omata, M
• 通讯作者: Omata, M

Otsuka M: "Comparing gene expression profiles in human liver, gastric, and pancreatic tissues using full-length-enriched cDNA libraries"Hepatol Res. 27. 76-82 (2003)

Otsuka M：“使用全长富集 cDNA 文库比较人类肝脏、胃和胰腺组织中的基因表达谱”Hepatol Res。

Taniguchi H: "Hepatitis C virus core protein upregulates transforming growth factor-β1 transcription"J Med Virol. 72. 52-59 (2004)

Taniguchi H：“丙型肝炎病毒核心蛋白上调转化生长因子-β1转录”J Med Virol。72. 52-59 (2004)

Kato J. et al.: "Hepatitis C virus NS4A and NS4B proteins supress translation in vivo"J Med Virol. 66. 187-199 (2002)

Kato J. 等人：“丙型肝炎病毒 NS4A 和 NS4B 蛋白抑制体内翻译”J Med Virol。

Goto T: "Hepatitis B virus HBX and the large hepatitis Delta antigen synergistically activate the SRE dependent pathway"J Infect Dis. 187. 820-828 (2003)

Goto T：“乙型肝炎病毒 HBX 和大肝炎 Delta 抗原协同激活 SRE 依赖性途径”J Infect Dis。