Modulation of HBV Replication by the Immunoproteasome

描述(申请人提供)：乙肝病毒(乙肝病毒)在感染者中引起自限性急性或慢性肝炎。全球约有3.5亿人慢性感染乙肝病毒，每年有100多万人死于肝硬变和肝细胞癌。这项应用的长期目标是确定调节乙肝病毒复制和持久性的细胞机制。从受感染的宿主清除乙肝病毒可能既需要干扰素(干扰素)诱导的非细胞病变抑制乙肝病毒复制，也需要病毒特异性细胞毒性T淋巴细胞(CTL)杀死感染的肝细胞。以前，已经证明干扰素通过蛋白酶体依赖的方式降低含有HBVRNA的衣壳的组装和/或稳定性来抑制乙肝病毒的复制。蛋白酶体是一种大的多亚单位的蛋白水解酶，它能降解细胞质和核蛋白，从而调节蛋白质的稳定性，并产生多肽供MHC I类分子呈递。因此，蛋白酶体和乙肝病毒之间的相互作用可能是病毒复制和感染进展为急性或慢性肝病的重要决定因素。因此，我们将检验这一假设，即干扰素对蛋白酶体活性的调节对于非细胞病理性抑制乙肝病毒复制以及宿主对病毒的适应性免疫反应都是至关重要的。在乙肝转基因小鼠和永生化肝细胞系中使用基于RNA干扰的方法，我们将确定干扰素诱导的蛋白酶体催化(LMP2，LMP7，MECL-1)或调节(PA28)亚单位是否介导了干扰素对乙肝病毒复制的抑制。我们还将研究LMP2和LMP7对针对乙肝病毒核心、聚合酶和包膜蛋白的CTL反应的大小、特异性和亲和力的影响，使用这些亚单位的遗传缺陷的人HLA-A2转基因小鼠。这些研究可能提供对宿主因素的更好的理解，这些宿主因素调节乙肝病毒复制并最终决定感染的结果。

DESCRIPTION (provided by applicant): The hepatitis B virus (HBV) causes either self-limiting acute or chronic hepatitis in infected individuals. Approximately 350 million people are chronically infected with HBV worldwide, leading to over 1 million deaths per year from cirrhosis and hepatocellular carcinoma. The long-term goal of this application is to define the cellular mechanisms that modulate the replication and persistence of HBV. The clearance of HBV from an infected host likely requires both the non-cytopathic inhibition of HBV replication induced by interferon (IFN), as well as the killing of infected hepatocytes by virus-specific cytotoxic T-lymphocytes (CTL). Previously, it has been demonstrated that IFN inhibits HBV replication by reducing the assembly and/or stability of HBV RNA-containing capsids in a proteasome-dependent manner. The proteasome is a large multisubunit protease that degrades cytoplasmic and nuclear proteins, thereby regulating protein stability and generating peptides for presentation by MHC class I molecules. The interaction between the proteasome and HBV may therefore be an important determinant of viral replication and the progression of infection to either acute or chronic liver disease. Thus, we will examine the hypothesis that regulation of proteasome activity by IFN is critical for both the non-cytopathic inhibition of HBV replication, as well as the host adaptive immune response to the virus. Using RNA interference-based approaches in HBV transgenic mice and immortalized hepatocyte cell lines, we will determine if the IFN-inducible proteasome catalytic (LMP2, LMP7, MECL-1) or regulatory (PA28) subunits mediate the inhibition of HBV replication by IFN. We will also examine the influence of LMP2 and LMP7 on the magnitude, specificity, and avidity of the CTL response to the HBV core, polymerase, and envelope proteins using human HLA-A2 transgenic mice genetically deficient for these subunits. These studies may provide a better understanding of the host factors that modulate HBV replication and that ultimately determine the outcome of infection.