Characterization and Consequences of HCV Interaction with Host Lipoproteins

描述（由申请人提供）：全球有超过1.7亿人感染丙型肝炎病毒（HCV），这是导致肝硬化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。HCV在受感染个体中作为一个基于浮力密度的异质人群传播，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。HCV与脂蛋白的结合在病毒颗粒组装过程中启动，后代HCV的释放与VLDL分泌途径密切相关。与脂蛋白，特别是HDL的相互作用也促进了进入易感细胞，这促进了快速进入动力学，从而促进了从中和抗体中逃脱。总之，这些数据支持HCV和脂蛋白之间的相互作用，并强调了它们在HCV发病机制中的作用，然而，这些脂蛋白如何与HCV相互作用的确切性质尚不清楚，其相互作用的全部后果尚未得到充分探讨。我们的总体假设是，HCV病毒粒子与宿主蛋白和脂质的结合或结合降低了病毒对中和的易感性。先前的研究表明，HCV表面糖蛋白E1和E2介导了脂蛋白相互作用。在Specific Aim 1中，我们将定义脂蛋白（特别是HDL）-HCV相互作用的特定分子需求，使用生化分析来解剖HDL复合物和糖蛋白诱变策略来确定结合的关键病毒残基。独立于病毒感染，脂蛋白已被证明具有免疫调节活性，高密度脂蛋白已被证明可以特别调节补体激活。因此，在特异性目的2中，我们将研究HCV与HDL的关联对补体介导的病毒溶解的病毒易感性的影响。我们的最终目标是对纯化的HCV进行完整的蛋白质组学和脂质组学分析。这些数据不仅将进一步阐明脂蛋白与病毒的相互作用，而且将使我们能够对病毒颗粒的细胞成分进行编目。这种分析将对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. PUBLIC HEALTH RELEVANCE: Over 170 million people world-wide are infected with HCV, a major cause of liver cirrhosis and hepatocellular carcinoma. No licensed vaccine or universally effective therapy is available to date and development of better treatment options will require further understanding of how HCV interacts with the host to establish persistent infection. To address this, the studies outlined in this application are designed to define the specific interaction between HCV and host lipoproteins and investigate the impact of this interaction on viral evasion of the host immune system.