Role of TLR3 Signaling in Control of HCV

描述：固有的细胞抗病毒防御能力可能会影响许多人类病毒感染的结局，包括丙型肝炎病毒(HCV)，一种正链RNA病毒，经常导致持续感染，导致慢性肝炎、肝硬变和肝癌。然而，人们对肝细胞如何感知丙型肝炎病毒感染并启动保护性反应知之甚少。我们最近发现，非肿瘤性PH5CH8肝细胞包含两条不同的抗病毒信号通路，Toll样受体3(TLR3)和维甲酸诱导基因I(RIG-I)，识别病毒双链(DS)RNA并导致随后的干扰素抗病毒反应。我们的长期目标是阐明这些信号通路在肝细胞控制丙型肝炎病毒感染中的作用。虽然RIG-I信号被证明有助于细胞内正义的丙型肝炎病毒RNA复制，但TLR3信号在识别和控制丙型肝炎病毒感染中的作用仍有待确定，因为以前的研究都是在缺乏TLR3途径的肝癌HuH7细胞中进行的。我们推测TLR3信号是肝细胞重要的抗病毒机制，有助于宿主抵御丙型肝炎病毒。我们提出了这一应用的三个目标：(1)确定TLR3在肝细胞中的亚细胞定位和TLR3信号在肝细胞中的启动机制，以及TLR3与RIG-I通路的相互作用程度。(2)确定结构化的丙型肝炎病毒RNA和丙型肝炎病毒感染是否激活了TLR3重组HUH细胞中的TLR3信号通路，以及TLR3是否与支持丙型肝炎病毒复制的细胞中的丙型肝炎病毒复制复合体相关。(3)确定TLR3信号是否参与肝细胞对丙型肝炎病毒复制的调控。这项拟议的研究将促进我们对丙型肝炎发病机制中病毒与宿主的相互作用以及先天免疫在控制丙型肝炎病毒感染中的作用的认识，这可能有助于设计新的丙型肝炎病毒感染的治疗措施。

DESCRIPTION: Innate cellular antiviral defenses are likely to influence the outcome of infections by many human viruses, including hepatitis C virus (HCV), a positive strand RNA virus that frequently establishes persistent infections leading to chronic hepatitis, cirrhosis and liver cancer. However, little is known about how hepatocytes sense HCV infection and initiate protective responses. We have recently shown that non-neoplastic PH5CH8 hepatocytes contain two distinct antiviral signaling pathways, Toll-like receptor 3 (TLR3) and retinoic acid-inducible gene I (RIG-I), to recognize viral double-stranded (ds) RNA and lead to subsequent interferon antiviral response. Our long-term goal is to elucidate the role of these signaling pathways in hepatocellular control of HCV infection. While RIG-I signaling was recently shown to contribute to sense intracellular HCV RNA replication, the role of TLR3 signaling in recognition and control of HCV infection remains to be determined, as previous investigations were all conducted in hepatoma Huh7 cells which lack a functional TLR3 pathway. We hypothesize that TLR3 signaling is an important antiviral mechanism of hepatocytes, and contributes to host defenses against HCV. We propose three aims for this application: (1) Determine the subcellular localization of TLR3 and the mechanism of TLR3 signaling in hepatocytes where it is initiated and to what extent it cross-talks with the RIG-I pathway. (2) Determine whether structured HCV RNA and HCV infection activate TLR3 signaling pathway in TLR3 reconstituted Huh cells and whether TLR3 is associated with HCV replication complex in cells supporting HCV replication. (3) Determine whether TLR3 signaling contributes to hepatocellular control of HCV replication. This proposed research shall advance our knowledge regarding virus-host interactions in hepatitis C pathogenesis and the role of innate immunity in controlling HCV infection, which would potentially benefit the design of new therapeutic interventions for HCV infection.