Molecular determinants of virulent arenavirus infection in hosts

描述（由申请人提供）：沙病毒如拉沙热病毒（LASV）可引起人类急性病毒性出血热，目前尚无疫苗或有效治疗方法。LASV的基础生物学、毒力机制和发病机制的研究受到了很大的阻碍，部分原因是BSL-4对这种选择剂的遏制要求严格，而且缺乏传染性克隆。拉沙热的一种小动物模型——豚鼠感染了同一沙病毒科的一种非致病性皮欣德病毒（PICV）——在临床和组织病理学发现上显示出与致命性人类拉沙热感染的许多相似之处。我们最近开发了两种密切相关的PICV毒株的传染性克隆，它们在豚鼠中显示出相反的疾病结果。此外，我们已经开发出安全方便的系统来表征沙粒病毒包膜糖蛋白（GPC）介导的细胞进入和LASV病毒RNA的体外合成。基于我们的初步结果，我们假设gpc介导的细胞进入和聚合酶蛋白L依赖的病毒RNA合成是沙粒病毒的两种主要毒力机制。我们建议利用我们实验室中可用的许多分子、遗传和动物系统来表征受感染宿主中毒力沙粒病毒感染的分子决定因素，并在分子水平上探索GPC和L蛋白的毒力机制。具体来说，我们希望(1)表征沙粒病毒出血热豚鼠模型中毒力感染的分子决定因素，(2)表征沙粒病毒GPC蛋白在细胞进入途径中的分子机制，(3)表征LASV L蛋白在病毒RNA合成、病毒复制和毒力中的分子机制。这些研究可能有助于确定针对拉沙热和其他沙粒病毒出血热疾病的潜在治疗靶点。

DESCRIPTION (provided by applicant): Arenaviruses such as Lassa fever virus (LASV) can cause acute viral hemorrhagic fever disease in humans, to which there is no vaccine or effective treatment. Studies on basic biology, virulent mechanism, and pathogenesis of LASV are significantly hindered, partly due to the strict requirement for BSL-4 containment to work with this select agent and the lack of infectious clones. A small animal model for Lassa fever - guinea pig infected with a non-pathogenic Pichinde virus (PICV) within the same Arenaviridae family - has shown many similarities in the clinical and histopathological findings to lethal human Lassa fever infections. We have recently developed the infectious clones for two closely related PICV strains that show opposing disease outcomes in guinea pigs. In addition, we have developed safe and convenient systems to characterize arenavirus envelope glycoprotein (GPC)-mediated cell entry and LASV viral RNA synthesis in vitro. Based on our preliminary results, we hypothesize that the GPC-mediated cell entry and the polymerase protein L- dependent viral RNA synthesis represent two major virulence mechanisms of arenavirus. We propose to utilize the many molecular, genetic, and animal systems that are available in our laboratory to characterize the molecular determinants of virulent arenavirus infection in the infected hosts and to explore the virulence mechanisms of the GPC and L proteins at molecular level. Specifically, we wish to (1) characterize the molecular determinants for virulent infection in a guinea pig model of arenavirus hemorrhagic fever, (2) characterize the molecular mechanism of arenavirus GPC protein in cell entry pathways, (3) characterize the molecular mechanism of LASV L protein in viral RNA synthesis, viral replication, and virulence. These studies may lead to identification of potential therapeutic targets against Lassa fever and other arenavirus hemorrhagic fever diseases. PUBLIC HEALTH RELEVANCE: Infection by Lassa fever virus or several other arenaviruses can lead to hemorrhagic fever (HF) diseases in humans, for which there is no vaccine (with the exception of Junin virus) or effective antiviral treatment. A related Pichinde virus in the same viral family is non-pathogenic in humans but causes distinct disease symptoms in guinea pigs that are similar to arenavirus HF in humans. We propose here to study the molecular mechanisms by which some arenaviruses can cause virulent infections in the hosts. These studies may lead to the development of effective treatments against the deadly arenavirus HF in humans.