Molecular determinants of virulent arenavirus infection in hosts

描述(申请人提供)：病毒如拉沙热病毒(LASV)可引起人类急性病毒性出血热疾病，目前还没有疫苗或有效的治疗方法。LASV的基础生物学、毒力机制和致病机理的研究显著受阻，部分原因是对BSL-4的严格要求与这种选择因子一起工作，以及缺乏感染性克隆。拉沙热的一个小动物模型--感染了同一个Arenaviridae家族中的非致病性Pichinde病毒(PICV)的豚鼠--在临床和组织病理学上显示出与致死性人类拉沙热感染的许多相似之处。我们最近为两个密切相关的PICV毒株开发了感染性克隆，这两个毒株在豚鼠身上表现出相反的疾病结果。此外，我们还开发了安全和方便的系统来表征病毒包膜糖蛋白(GPC)介导的细胞进入和LASV病毒RNA的体外合成。根据我们的初步结果，我们推测GPC介导的细胞进入和依赖于聚合酶蛋白L的病毒核糖核酸合成是ArenaVirus的两种主要毒力机制。我们建议利用本实验室现有的分子、遗传和动物系统来表征感染宿主中ARV强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。具体地说，我们希望(1)在豚鼠ArenaVirus出血热模型中表征毒力感染的分子决定因素；(2)表征ArenaVirus gpc蛋白在细胞进入途径中的分子机制；(3)表征LASV L蛋白在病毒核糖核酸合成、病毒复制和毒力方面的分子机制。这些研究可能导致确定拉沙热和其他阿雷纳病毒出血热疾病的潜在治疗靶点。 公共卫生相关性：感染拉沙热病毒或其他几种阿拉伯病毒可导致人类患出血热(HF)疾病，目前尚无疫苗(Junin病毒除外)或有效的抗病毒治疗。同一病毒家族中的一种相关的Pichinde病毒在人类中是非致病性的，但会在豚鼠中引起明显的疾病症状，类似于人类的阿雷纳病毒HF。我们建议在这里研究一些禽类病毒在宿主中引起毒力感染的分子机制。这些研究可能会导致开发有效的治疗方法来对抗人类致命的禽流感病毒HF。

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.