Innate Control of Hepatitis C Virus Infection: Antiviral and Evasion Mechanisms

描述（由申请人提供）：这些研究的长期目标是确定在丙型肝炎病毒（HCV）感染期间发生的先天宿主-病毒相互作用，希望这将导致新的治疗方法。HCV是一种非细胞病变的正链RNA病毒，可引起急性和慢性肝炎和肝细胞癌。在美国大约有2-4百万人慢性感染丙型肝炎病毒，全世界有1.7亿人慢性感染丙型肝炎病毒，其中许多人将死于肝功能衰竭和肝细胞癌。最近HCV感染的一个强大的细胞培养模型的发展允许分析整个HCV生命周期，并有助于分析决定HCV感染结果的宿主-病毒相互作用。使用该模型，我们最近报道了HCV不会在感染细胞中诱导1型干扰素或干扰素刺激基因；病毒NS3/4A蛋白酶通过切割dsRNA信号通路中的一个关键中间体来阻断双链RNA信号传导；HCV通过一种全新的不依赖ns3 / 4a的机制在感染细胞中逃避先天宿主反应，该机制由HCV NS4B蛋白介导。我们还发现，1型干扰素可以快速调节细胞microrna （mirna）亚群的表达，这些亚群部分介导IFN对HCV的抗病毒作用。这些发现确定了干扰素反应的一个以前未被怀疑的效应臂，有助于控制HCV感染。在目前的建议中，我们将以以下具体目标扩展这些研究。在Specific Aim 1中，我们将通过确定NS4B是否直接与RIG-I相互作用，是否调节RIG-I亚细胞定位，以及是否阻断RIG-I结合dsRNA的能力，来表征NS4B阻断双链rna信号传导的分子机制。在特异性目标2中，我们将鉴定介导干扰素对HCV抗病毒作用的细胞mirna库，鉴定介导其抗病毒作用的细胞基因，并表征这些基因控制HCV感染的机制。总的来说，这些实验将提供对病毒逃避和宿主防御机制的见解，这可能导致开发新的抗病毒策略来终止慢性HCV感染。

DESCRIPTION (provided by applicant): The long term goal of these studies is to define the innate host-virus interactions that occur during hepatitis C virus (HCV) infection with the hope that this will lead to novel therapeutic approaches to this disease. HCV is a noncytopathic, positive-strand RNA virus that causes acute and chronic hepatitis and hepatocellular carcinoma. Approximately 2-4 million persons are chronically infected by HCV in the USA and 170 million people are chronically infected worldwide, many of whom will die from liver failure and hepatocellular carcinoma. The recent development of a robust cell culture model of HCV infection permits analysis of the entire HCV life cycle and facilitates analysis of the host-virus interactions that determine the outcome of HCV infection. Using that model we recently reported that HCV doesn't induce type 1 interferon or interferon stimulated genes in infected cells; that the viral NS3/4A protease blocks double stranded (ds) RNA signaling by cleaving a key intermediate in the dsRNA signaling pathway; and that HCV evades the innate host response in infected cells by an entirely novel NS3/4A-independent mechanism that is mediated by the HCV NS4B protein. We also discovered that type 1 interferon rapidly modulates the expression of a subset of cellular microRNAs (miRNAs) that partially mediate the antiviral effects of IFN against HCV. These findings identify a previously unsuspected effector arm of the interferon response that contributes to the control of HCV infection. In the current proposal we will extend these studies with the following Specific Aims. In Specific Aim 1, we will characterize the molecular mechanism whereby NS4B blocks double stranded RNA-signaling by determining if it directly interacts with RIG-I, if it regulates RIG-I subcellular localization, and if it blocks the ability of RIG-I to bind dsRNA. In Specific Aim 2, we will identify the repertoire of cellular miRNAs that mediate the antiviral effect of interferon against HCV, identify the cellular genes that mediate their antiviral effects, and characterize the mechanism whereby those genes control HCV infection. Collectively, these experiments will provide insight into viral evasion and host defense mechanisms that could lead to the development of novel antiviral strategies to terminate chronic HCV infection.