Role of TLR3 Signaling in Control of HCV

产品说明：先天细胞抗病毒防御可能会影响许多人类病毒感染的结果，包括丙型肝炎病毒（HCV），这是一种正链RNA病毒，经常引起持续性感染，导致慢性肝炎、肝硬化和肝癌。然而，肝细胞如何感知HCV感染并启动保护性反应却知之甚少。我们最近发现，非肿瘤性PH 5CH 8肝细胞含有两个不同的抗病毒信号通路，Toll样受体3（TLR 3）和视黄酸诱导基因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HCV感染中的作用。虽然RIG-I信号最近显示有助于有义细胞内HCV RNA复制，但TLR 3信号在识别和控制HCV感染中的作用仍有待确定，因为先前的研究都是在缺乏功能性TLR 3途径的肝癌Huh 7细胞中进行的。我们假设TLR 3信号传导是肝细胞的重要抗病毒机制，并有助于宿主防御HCV。我们提出了三个应用目标：（1）确定TLR 3的亚细胞定位和TLR 3信号转导机制在肝细胞中的起始位置以及它与RIG-I通路的交叉程度。(2)确定结构化HCV RNA和HCV感染是否激活TLR 3重建的Huh细胞中的TLR 3信号通路，以及TLR 3是否与支持HCV复制的细胞中的HCV复制复合物相关。(3)确定TLR 3信号传导是否有助于肝细胞控制HCV复制。这项拟议的研究将提高我们对丙型肝炎发病机制中病毒-宿主相互作用以及先天免疫在控制HCV感染中的作用的认识，这将可能有利于设计新的HCV感染治疗干预措施。

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.