The Molecular Basis of VEEV Pathogenesis

描述（由申请人提供）：披膜病毒科甲病毒属包括许多重要的人类和动物病原体，包括委内瑞拉（VEEV）、东方（EEEV）和西方马脑炎（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不断传播，并有能力在人类和马匹中引起致命疾病。此外，EEEV、WEEV，特别是VEEV有可能被恐怖分子利用，并被用作生物战剂。尽管VEEV流行病的持续威胁，但VEEV的生物学，特别是其高毒力的分子基础，与其他甲病毒相比研究较少。据信，辛德毕斯（SINV）和塞姆利基森林（SFV）病毒，这是显着低于VEEV的致病性，代表了良好的模型，用于研究VEEV复制和病毒-宿主相互作用的机制。然而，最近的VEEV和SINV的比较研究结果表明，VEEV的复制和其发病机制与以前描述的SINV有很大的不同。因此，我们关于SINV生物学的大部分知识不能直接应用于VEEV。我们的初步研究强烈表明，VEEV衣壳在抑制核质运输和细胞转录中起关键作用，因此，下调先天免疫应答。我们的研究结果还表明VEEV基因组的5 'UTR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衣壳和5 'UTR在病毒复制中的功能，并在不同水平上确定病毒的致病机制。拟议的实验分为三个目标。在具体目标1中，我们打算定义VEEV衣壳在核质转运抑制中的功能。在具体目标2中，我们将在分子和细胞水平上详细研究5 'UTR序列中的菌株特异性突变对VEEV复制和发病机制的影响;在具体目标3中，我们将应用已经获得的信息和将在我们提出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菌株。具体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。本研究的结果也适用于其他致脑炎甲病毒，如EEEV和WEEV。 公共卫生相关性：甲病毒包括一组广泛分布的人类和动物病原体;其中一些引起高度衰弱性疾病，并在美国构成严重的公共卫生威胁。本申请的目的是了解病毒蛋白在病毒复制和开发抗致脑炎甲病毒的新型高度减毒活疫苗期间细胞内环境修饰中的作用。

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.