The Molecular Basis of VEEV Pathogenesis

描述(申请人提供)：Togaviridae家族的甲型病毒属包括一些重要的人类和动物病原体，包括委内瑞拉(VEEV)、东部(EEEV)和西部马脑炎(Weev)病毒。后者在美国构成了严重的公共卫生威胁，因为它们在自然界中持续循环，并有能力导致人和马的致命疾病。此外，EEEV、WeEV，特别是VEEV有可能被恐怖分子用作生物战剂。尽管VEEV流行的威胁持续不断，但VEEV的生物学，特别是其高毒力的分子基础，与其他甲型病毒相比，一直没有得到深入的研究。辛德比斯(SINV)和塞姆利基森林病毒(SFV)的致病性大大低于VEEV，被认为是研究VEEV复制机制和病毒与宿主相互作用的良好模型。然而，最近与VEEV和SINV的比较研究结果表明，VEEV的复制及其致病机制与以前对SINV的描述有很大不同。因此，我们关于SINV生物学的大部分知识不能直接应用于VEEV。我们的初步研究有力地表明，VEEV衣壳在抑制核质转运和细胞转录方面发挥关键作用，从而下调先天性免疫反应。我们的结果还表明VEEV基因组的5‘非编码区是病毒致病的重要决定因素之一。因此，本研究旨在进一步了解VEEV衣壳蛋白和5‘端非编码区在病毒复制中的作用，并从不同水平确定病毒的致病机制。建议的实验分为三个目标。在特定的目标1中，我们打算定义VEEV衣壳在核质转运抑制中的功能。在特定的目标2中，我们将在分子和细胞水平上详细研究5‘非编码区的毒株特异性突变对VEEV复制和致病的影响；在特定的目标3中，我们将应用已有的信息和将在我们提议的实验中产生的新数据来开发用于疫苗应用的新的高度减毒的VEEV毒株。具体的目标代表了三个独立的研究方向，但预计它们将产生补充数据。这项研究的结果也将适用于其他脑源性甲型病毒，如EEEV和WeEV。 与公共卫生相关：甲型病毒包括一组广泛分布的人类和动物病原体；其中一些会导致高度衰弱的疾病，并在美国构成严重的公共卫生威胁。这项应用的目的是了解病毒蛋白在病毒复制和开发针对脑源性甲型病毒的高度减毒活疫苗开发过程中对细胞内环境的改变所起的作用。

DESCRIPTION (provided by applicant): The Alphavirus genus in the Togaviridae family includes a number of important human and animal pathogens, including Venezuelan (VEEV), eastern (EEEV) and western equine encephalitis (WEEV) viruses. The latter constitute a serious public health threat in the US, because they continuously circulate in nature and have the ability to cause fatal disease in humans and horses. In addition, EEEV, WEEV and, in particular, VEEV have the potential for use by terrorists and as biological warfare agents. In spite of the continuous threat of VEEV epidemics, the biology of VEEV, in particular the molecular basis of its high virulence, has been studied less intensively than that of other alphaviruses. It was believed that Sindbis (SINV) and Semliki Forest (SFV) viruses, which are dramatically less pathogenic than VEEV, represent good models for studying the mechanism of VEEV replication and virus-host interactions. However, results from recent comparative studies with VEEV and SINV suggested that VEEV replication and its pathogenesis strongly differ from those previously described for SINV. Hence, a great part of our knowledge about SINV biology cannot be directly applied to VEEV. Our preliminary studies strongly suggested that the VEEV capsid plays critical roles in inhibiting both nucleocytoplasmic trafficking and cellular transcription and, thus, downregulation of the innate immune response. Our results also suggested the 5'UTR of the VEEV genome is one of the important determinants of viral pathogenesis. Therefore, the proposed research is aimed at further understanding the functions of VEEV capsid and 5'UTR in virus replication, and in determining virus pathogenesis at different levels. The proposed experiments are organized into three aims. In specific aim 1, we intend to define functioning of VEEV capsid in the nucleocytoplasmic transport inhibition. In specific aim 2, we will perform a detailed investigation of the effects of the strain-specific mutations in the 5'UTR sequence on VEEV replication and pathogenesis on molecular and cellular levels; and in specific aim 3, we will apply already available information and new data that will be generated in our proposed experiments to develop new, highly attenuated strains of VEEV for vaccine applications. The specific aims represent three independent lines of research, but they are expected to generate complementary data. The results of this study will also be applicable to other encephalitogenic alphaviruses, such as EEEV and WEEV. PUBLIC HEALTH RELEVANCE: Alphaviruses comprise a group of widely distributed human and animal pathogens; some of them induce highly debilitating diseases and represent a serious public health threat in the US. The goal of this application is to understand the role of viral proteins in modification of the intracellular environment during virus replication and development of new, highly attenuated, live vaccines against encephalitogenic alphaviruses.