Hepatitis C virus and autophagic response

描述(申请人提供)：丙型肝炎病毒(丙型肝炎病毒)是一种重要的人类病原体，可导致严重的肝脏疾病，包括肝硬变和肝细胞癌。最近，我们的实验室发现，丙型肝炎病毒可以干扰自噬途径，导致自噬小体在细胞内积聚。自噬在维持细胞内环境平衡方面起着重要作用。丙型肝炎病毒在慢性感染期间持续扰乱自噬途径的能力在丙型肝炎病毒的发病机制和肿瘤发生中具有深远的后果。我们的进一步研究揭示了丙型肝炎病毒RNA复制复合体与自噬体膜的关联，表明丙型肝炎病毒诱导自噬小体促进其RNA合成。显然，丙型肝炎病毒通过抑制自噬小体与溶酶体的融合来诱导自噬小体。有趣的是，我们的初步研究还表明，丙型肝炎病毒通过一种不依赖于3类磷脂酰肌醇-3-激酶(PI3KC3)的新机制诱导自噬小体的生物发生。在这一应用中，我们建议继续我们的新发现来研究丙型肝炎病毒如何抑制自噬小体的成熟。具体地说，我们将测试这一假设，即丙型肝炎病毒诱导Rubcon从HOPS复合体中隔离UVRAG，以抑制自噬小体的成熟。此外，我们还将阐明丙型肝炎病毒诱导自噬小体生物发生的分子途径。最后，我们还将使用我们最近开发的一种新方法来纯化丙型肝炎病毒感染细胞中的自噬小体，并对其相关蛋白因子进行表征，以了解这些膜小泡的生物发生以及自噬小体与丙型肝炎病毒RNA复制复合体之间的关系。我们的研究将为我们了解丙型肝炎病毒与其宿主细胞之间的相互作用以及更好地理解丙型肝炎病毒的复制和发病机制提供重要的信息。

DESCRIPTION (provided by applicant): Hepatitis C virus (HCV) is an important human pathogen that can cause severe liver diseases including liver cirrhosis and hepatocellular carcinoma. Recently, our laboratory discovered that HCV could perturb the autophagic pathway, leading to the accumulation of autophagosomes in cells. Autophagy plays an important role in maintaining cellular homeostasis. The ability of HCV to persistently perturb the autophagic pathway during chronic infection can have profound consequences in HCV pathogenesis and oncogenesis. Our further studies revealed the association of the HCV RNA replication complex with autophagosomal membranes, suggesting that HCV induces autophagosomes to facilitate its RNA synthesis. HCV apparently induces autophagosomes by inhibiting their fusion with lysosomes. Interestingly, our preliminary studies also indicate that HCV induces the biogenesis of autophagosomes via a novel mechanism independent of the class 3 phosphatidylinositol-3-kinase (PI3KC3). In this application, we propose to continue our novel findings to study how HCV inhibits the maturation of autophagosomes. Specifically, we will test the hypothesis that HCV induces Rubicon to sequester UVRAG from the HOPS complex to inhibit the maturation of autophagosomes. In addition, we will also elucidate the molecular pathway of HCV-induced biogenesis of autophagosomes. Finally, we will also use a novel approach that we recently developed to purify autophagosomes from HCV-infected cells and to characterize their associated protein factors to understand the biogenesis of these membrane vesicles and the relationship between autophagosomes and the HCV RNA replication complex. Our proposed research will generate important information for us to understand the interaction between HCV and its host cell and lead to a better understanding of HCV replication and pathogenesis.