Characterization and Consequences of HCV Interaction with Host Lipoproteins

描述(申请人提供)：全球有超过1.7亿人感染丙型肝炎病毒(丙型肝炎病毒)，这是导致肝硬变和肝细胞癌的主要原因。尽管丙型肝炎病毒在全球流行，但人们对这种病毒如何与宿主相互作用并逃避免疫系统以建立持续感染知之甚少。丙型肝炎病毒在感染者中以浮力密度为基础的异质性群体在感染个体中循环，这种异质性部分是由于病毒与脂蛋白-包括极低密度(VLDL)、低密度(LDL)和高密度(HDL)脂蛋白-的关联。丙型肝炎病毒与脂蛋白的结合始于病毒颗粒的组装，子代丙型肝炎病毒的释放与极低密度脂蛋白的分泌途径密切相关。与脂蛋白，特别是高密度脂蛋白的相互作用也促进了进入敏感细胞的过程，这促进了进入细胞的快速动力学，从而有助于逃避中和抗体。总之，这些数据支持丙型肝炎病毒和脂蛋白之间的相互作用，并强调了它们在丙型肝炎发病机制中的作用，然而，这些脂蛋白如何与丙型肝炎病毒相互作用的确切性质尚不清楚，它们相互作用的全部后果也没有得到充分的研究。我们的总体假设是，丙型肝炎病毒粒子与宿主蛋白和脂类结合或结合，可降低病毒对中和的敏感性。先前的研究表明，脂蛋白相互作用是由丙型肝炎病毒表面糖蛋白E1和E2介导的。在特定的目标1中，我们将定义脂蛋白(特别是高密度脂蛋白)与丙型肝炎病毒相互作用的特定分子要求，使用生化分析来剖析高密度脂蛋白复合体，并使用糖蛋白突变策略来确定关键的病毒残基以结合。脂蛋白与病毒感染无关，已被证明具有免疫调节活性，而高密度脂蛋白已被明确地显示为调节补体激活。因此，在特定的目标2中，我们将研究丙型肝炎病毒与高密度脂蛋白的关联对病毒对补体介导的病毒裂解的易感性的影响。我们的最终目标是对纯化的丙型肝炎病毒进行完整的蛋白质组和脂组学分析。这些数据不仅将进一步阐明脂蛋白与病毒的相互作用，而且还将使我们能够对病毒颗粒的细胞成分进行分类。这样的分析将为了解丙型肝炎病毒颗粒的组成及其生命周期提供有价值的见解。

DESCRIPTION (provided by applicant): Over 170 million people world-wide are infected with hepatitis C virus (HCV), a major cause of liver cirrhosis and hepatocellular carcinoma. Despite the global prevalence of HCV, little is known about how this virus interacts with the host and evades the immune system to establish persistent infection. HCV circulates in infected individuals as a heterogeneous population based on buoyant density and this heterogeneity is due in part to virus association with lipoproteins - including very low density (VLDL), low density (LDL) and high density (HDL) lipoproteins. HCV association with lipoproteins initiates during virus particle assembly, and release of progeny HCV is closely linked to the VLDL secretory pathway. Entry into susceptible cells is also facilitated by interaction with lipoproteins, specifically HDL, which promotes rapid kinetics of entry thought to facilitate escape from neutralizing antibodies. Together, these data support the interaction between HCV and lipoproteins and underscore their role in HCV pathogenesis, however, the precise nature of how these lipoproteins interact with HCV is unknown and the full consequences of their interaction not fully explored. Our overall hypothesis is that HCV virion association with, or incorporation of, host proteins and lipids reduces virus susceptibility to neutralization. Previous studies indicate that lipoprotein interaction is mediated by the HCV surface glycoproteins, E1 and E2. In Specific Aim 1, we will define the specific molecular requirements for lipoprotein (specifically HDL)-HCV interaction using both biochemical assays to dissect the HDL complex and a glycoprotein mutagenesis strategy to identify critical viral residues for binding. Independent of viral infection, lipoproteins have been shown to have immunoregulatory activities, and HDL has specifically been shown to modulate complement activation. Thus, in Specific Aim 2 we will investigate the impact of HCV association with HDL on virus susceptibility to complement-mediated virolysis. Our final Specific Aim is to perform complete proteomic and lipidomic analyses on purified HCV. These data will not only further elucidate the lipoprotein-virus interaction, but will also enable us to catalog the cellular components of the virus particle. Such analyses will provide valuable insight into the composition of the HCV particle and its life cycle.