CARD14 is essential for hepatitis C virus replication and activation of NFKB

描述（由申请人提供）：丙型肝炎病毒（HCV）感染困扰着全球约1.7亿人，这些人的慢性病毒感染是肝细胞癌（HCC）的重要原因。HCV诱导HCC的机制在很大程度上是未知的，但病毒诱导宿主细胞信号传导途径的改变以创建病毒的复制小生境并避免宿主抗病毒程序可能是这种发病机制的重要组成部分。使用基因组规模的siRNA筛选，我们已经确定了宿主蛋白CARD 14作为HCV RNA复制的重要因素。CARD 14是已知的NF-κ B通路的调节因子，但其在生物学中的确切功能尚不清楚。我们的初步数据显示，HCV感染细胞导致NF-κ B活化显著增加，并且这种活化依赖于CARD 14蛋白的存在。许多感染因子改变NF-kB基因表达以促进宿主细胞的存活，并且在慢性HCV感染期间长期操纵该途径可能是导致癌症发展的因素之一。我们的假设是，CARD 14依赖性激活NF-κ B通路是有效的HCV RNA复制和预防感染细胞凋亡所必需的，并且HCV对该通路的操纵是HCC发展的重要因素。CARD 14如何在NF-κ B信号传导中发挥作用，病毒如何操纵这一途径，以及这种操纵导致基因表达的变化是需要解决的重要问题，我们设计了四个具体目标来解决这些重要问题。我们建议验证CARD 14和NF-kB激活之间的联系，映射CARD 14的哪些区域是NF-kB激活和HCV复制所需的，确定CARD 14是否作为细胞凋亡的调节因子发挥作用，定义作为CARD 14信号通路一部分的蛋白质，并确定CARD 14在HCV感染期间操纵哪些细胞基因。这些目标的完成将大大增加我们对HCV复制的细胞要求，HCV对NF-κ B信号传导的操纵以促进细胞存活以及CARD 14在这些过程中的功能的理解。这些实验对HCV感染者发生HCC具有重要的潜在意义。

DESCRIPTION (provided by applicant): Hepatitis C virus (HCV) infection afflicts approximately 170 million people worldwide and chronic virus infection in these individuals is a significant cause of hepatocellular carcinoma (HCC). The mechanisms by which HCV induces HCC are largely unknown, but it is likely that virus induced alteration of host cell signaling pathways to create a replication niche for the virus and avoid the host anti-viral program is an important component of this pathogenesis. Using genomic scale siRNA screening, we have identified the host protein CARD14 as an important factor for HCV RNA replication. CARD14 is a known regulator of the NF-kB pathway, but its precise function in biology is unknown. Our preliminary data shows that infection of cells by HCV leads to a dramatic increase in NF-kB activation, and this activation is dependent on the presence of the CARD14 protein. Many infectious agents alter NF-kB gene expression to promote survival of the host cell, and the long-term manipulation of this pathway during chronic HCV infection may be one factor leading to the development of cancer. Our hypothesis is that CARD14 dependent activation of the NF-kB pathway is required for efficient HCV RNA replication and the prevention of apoptosis in infected cells, and that manipulation of this pathway by HCV is an important factor in the development of HCC. The details of how CARD14 functions in NF-kB signaling, how the virus manipulates this pathway, and what changes in gene expression result from this manipulation are important questions that need to be addressed, and we have designed four specific aims to address these important questions. We propose to validate the connection between CARD14 and NF-kB activation, map what regions of CARD14 are required for NF-kB activation and HCV replication, determine if CARD14 is functioning as a regulator of apoptosis, define proteins that are part of the CARD14 signaling pathway, and determine what cellular genes CARD14 manipulates during HCV infection. The completion of these aims will add considerably to our understanding of the cellular requirements for HCV replication, the manipulation of NF-kB signaling by HCV to promote cell survival, and the function of CARD14 in these processes. These experiments are of great potential significance to the development of HCC in those infected with HCV.