Characterization and Consequences of HCV Interaction with Host Lipoproteins

描述（由申请人提供）：全世界有超过1.7亿人感染丙型肝炎病毒（HCV），这是肝硬化和肝细胞癌的主要原因。尽管HCV在全球范围内流行，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在感染个体中作为基于浮力密度的异质群体循环，并且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-的结合。HCV与脂蛋白的结合起始于病毒颗粒组装期间，并且子代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，这促进了进入的快速动力学，被认为有助于从中和抗体中逃逸。总之，这些数据支持HCV和脂蛋白之间的相互作用，并强调它们在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是未知的，其相互作用的全部后果没有充分探讨。我们的总体假设是，HCV病毒体与宿主蛋白质和脂质的结合或掺入降低了病毒对中和的敏感性。以前的研究表明，脂蛋白相互作用是由HCV表面糖蛋白，E1和E2介导的。在具体目标1中，我们将使用生物化学测定法来解剖HDL复合物和糖蛋白诱变策略来确定脂蛋白（特别是HDL）-HCV相互作用的特定分子要求，以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，并且HDL已被特别地证明调节补体激活。因此，在具体目标2中，我们将研究HCV与HDL的关联对病毒对补体介导的病毒溶解的易感性的影响。我们最终的具体目标是对纯化的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-病毒相互作用，而且还将使我们能够对病毒颗粒的细胞组分进行编目。这种分析将提供有价值的深入了解HCV颗粒的组成及其生命周期。 公共卫生相关性：全球有超过1.7亿人感染丙型肝炎病毒，这是肝硬化和肝细胞癌的主要原因。迄今为止，没有获得许可的疫苗或普遍有效的治疗方法，更好的治疗方案的开发将需要进一步了解HCV如何与宿主相互作用以建立持续感染。为了解决这个问题，本申请中概述的研究旨在定义HCV和宿主脂蛋白之间的特异性相互作用，并研究这种相互作用对宿主免疫系统病毒逃避的影响。

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.