Roles for RCK/DDX6 in hepatitis C virus pathogenesis and hepatocellular carcinoma

RCK/DDX6 在丙型肝炎病毒发病机制和肝细胞癌中的作用

• 批准号: 7698228
• 负责人: PETER SARNOW
• 金额: $ 29.58万
• 依托单位: STANFORD UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-07-17 至 2011-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7698228
• 关键词: Affect; Alcohol abuse; Antiviral Therapy; Biochemical; Biological Assay; Boxing; Cancer Etiology; Cell physiology; Cells; Cessation of life; Chronic; Cirrhosis; Cytolysis; Cytoplasmic Granules; Degradation Pathway; Detection; Disease; Economic Burden; Family; Fractionation; Gene Amplification; Gene Expression; Gene Expression Regulation; Genome; Goals; Hepatitis B; Hepatitis C; Hepatitis C virus; Hepatocyte; Immunoprecipitation; In Situ Hybridization; Individual; Infection; Interferons; Intravenous; Lead; Life; Liver; Liver diseases; Malignant neoplasm of liver; Mammalian Cell; Measures; Mediating; MicroRNAs; Monitor; Nature; Oligonucleotides; Pathway interactions; Patients; Plasmids; Primary carcinoma of the liver cells; Proteins; RNA; RNA chemical synthesis; Ribavirin; Ribosomes; Role; Staging; Stress; Structure; System; Technology; Toxic Environmental Substances; Transfection; Translation Initiation; UV induced; Up-Regulation; Viral; Viral Genome; Viral Proteins; Virus Replication; cancer cell; cellular targeting; cholesterol biosynthesis; combat; crosslink; helicase; member; new technology; novel; overexpression; protein complex; reconstitution; research study; tool; viral RNA; virus pathogenesis

Hepatocellular carcinoma (HCC) is a leading cause of cancer-related deaths. Although many cases of HCC are induced by chronic alcohol abuse or environmental toxins, approximately 80% are caused by infection with either hepatitis B or hepatitis C virus (HCV). The burden of HCV infection worldwide is very large, with most of the personal and economic burden yet to come, as cirrhosis and HCC take years to develop. Approximately 170 million people are infected worldwide with HCV. Most infected individuals do not clear the disease, but develop chronic infections that often lead to end-stage liver disease and HCC. Current treatment is limited to co-treatment with ribavirin and interferon , a therapy that is expensive and ineffective in 50% of infected individuals. Therefore, there is an urgent need to identify new and accessible viral and cellular targets for therapies against HCV and HCC. It has been shown recently that cellular microRNAs, especially those in the liver, can be readily inactivated by direct intravenous delivery of modified oligonucleotides. Thus, our finding that liver-specific microRNA miR-122 interacts directly with the viral 5’ noncoding region of HCV and that this interaction is essential to maintain intracellular abundance of the viral RNA, identifies a promising target for antiviral therapy. What are the host proteins required for microRNA expression in the liver? Recently, it has been found that host cell protein RCK/DDX6, a member of the DEAD box helicase family, is important for microRNA-mediated gene regulation in mammalian cells and that both miR-122 and RCK are greatly overexpressed in HCV-induced HCC in patient livers. Our preliminary results have shown that RCK is an essential positive regulator of HCV gene expression; depletion of RCK results in loss of HCV proteins. In this proposal, we propose to examine the mechanism by which RCK upregulates HCV gene expression at an apparently post-transcriptional step and by which RCK affects microRNA abundance and intracellular distribution in uninfected and HCV-infected liver cells. Using novel in situ hybridization technology, we will determine the effect of RCK expression on microRNA localization to specific cytoplasmic compartments known as P-bodies and stress granules. Finally, we propose experiments to identify targets for microRNAs whose abundance and distribution is affected by RCK, These studies will develop novel tools for HCV and HCC and are likely to point to new targets for antiviral therapy.

肝细胞癌 (HCC) 是癌症相关死亡的主要原因，尽管许多 HCC 病例是由长期酗酒或环境毒素引起的，但大约 80% 是由乙型肝炎或丙型肝炎病毒 (HCV) 感染引起的。全世界 HCV 感染的负担非常大，大部分个人和经济负担尚未到来，因为全球大约有 1.7 亿人感染 HCV，肝硬化和 HCC 需要数年时间才能形成。大多数感染者无法清除疾病，而是发展为慢性感染，通常导致终末期肝病和 HCC。目前的治疗仅限于利巴韦林和干扰素  的联合治疗，这种疗法价格昂贵且对 50% 的患者无效。因此，迫切需要确定新的、可利用的病毒和细胞靶点来治疗 HCV 和 HCC。最近的研究表明，细胞 microRNA，尤其是肝脏中的 microRNA，可以通过直接静脉注射轻松灭活。因此，我们发现肝脏特异性 microRNA miR-122 直接与 HCV 病毒 5' 非编码区相互作用，并且这种相互作用对于维持病毒 RNA 的细胞内丰度至关重要，从而确定了一个有希望的抗病毒治疗靶点。肝脏中microRNA表达所需的宿主蛋白有哪些？最近发现宿主细胞蛋白RCK/DDX6（DEAD box解旋酶家族的成员）对于microRNA介导的基因调控具有重要作用。哺乳动物细胞中，miR-122 和 RCK 在 HCV 诱导的 HCC 患者肝脏中显着过度表达。在本提案中，我们建议研究 RCK 在转录后明显上调 HCV 基因表达的机制，以及 RCK 影响未感染和感染者中 microRNA 丰度和细胞内分布的机制。 HCV 感染的肝细胞。使用新型原位杂交技术，我们将确定 RCK 表达对称为 P 体和应激颗粒的特定细胞质区室的 microRNA 定位的影响。这些研究将开发针对 HCV 和 HCC 的新工具，并可能指出抗病毒治疗的新靶点。