The Mammalian NRAMP family as Alphavirus Pathogenesis Determinants

描述（由申请人提供）：甲病毒如基孔肯雅病毒（CHIKV）和委内瑞拉马脑炎病毒（VEEV）是已知可引起爆炸性流行病的重要新发人类病原体。这些病毒是人类病毒性脑炎暴发或反复出现疼痛性关节痛的原因。每年，它们都有可能从蚊子或鸟类宿主传播到新的地区。在病媒监测和症状管理方面投入了大量资金，但预防甲病毒感染的治疗方法和疫苗取得的成功有限。本小组研究了甲病毒在体内的发病机制，包括CHIKV和Sindbis病毒（SINV）。这些类型的研究可以通过加强对感染期间发生的分子事件的理解，有助于设计更有效的治疗方法和疫苗。我们的长期目标是了解甲病毒与其宿主相互作用的确切机制。在这项提议中，我们研究了SINV与两个相关受体，哺乳动物NRAMP 1和2之间的相互作用。甲型病毒Sindbis病毒（SINV）感染哺乳动物细胞需要天然耐药相关巨噬细胞蛋白2 （NRAMP2）进入。然而，这一要求从未在体内进行过评估。此外，SINV与密切相关且功能相似的NRAMP1蛋白之间的相互作用从未被评估过。因此，我们在本研究中的目的是确定NRAMP2利用对SINV发病机制的影响，并确定NRAMP1是否存在类似的作用。我们假设哺乳动物NRAMP蛋白是SINV趋向性和发病机制的重要决定因素。为了实现我们的目标，我们提出了以下目标。在SPECIFIC AIM 1中，我们将分析NRAMP2在宿主疾病易感性和病毒趋向性中的作用。我们将使用组织特异性和可诱导的NRAMP2敲除小鼠模型来实现这一目标。在SPECIFIC AIM 2中，我们将研究NRAMP1是否在SINV感染期间作为额外的进入受体起作用。我们将使用体外模型过表达NRAMP1，并通过SINV确定小鼠或人类NRAMP1与NRAMP2的相对利用率。这些研究将确定哺乳动物NRAMP表达对SINV感染和疾病的确切影响。这些目标的成功完成可能表明NRAMP蛋白是合适的和新的治疗靶点。拟议的研究为申请人提供了影响甲病毒发病机制的病毒-宿主相互作用的良好培训来源。

DESCRIPTION (provided by applicant): Alphaviruses such as Chikungunya virus (CHIKV) and Venezuelan equine encephalitis virus (VEEV) are important emerging human pathogens known to cause explosive epidemics. These viruses are responsible for outbreaks of viral encephalitis or painful recurring arthralgia in humans. Each year they have the potential to spread from a mosquito or avian reservoir to new regions. Large sums have been invested in vector surveillance and symptom management, but therapeutics and vaccines that protect against alphavirus infection have had limited success. Our group studies the pathogenesis of alphaviruses in vivo, including CHIKV and Sindbis virus (SINV). These kinds of studies can contribute to the design of more effective therapeutics and vaccines through an enhanced understanding of the molecular events that occur during infection. Our LONG-TERM GOAL is to understand the exact mechanisms of alphavirus interactions with their hosts. In this proposal, we investigate the interaction between SINV and two related receptors, mammalian NRAMP 1 and 2. Infection of mammalian cells by the alphavirus Sindbis virus (SINV) requires natural resistance-association macrophage protein 2 (NRAMP2) for entry. However, this requirement has never been evaluated in vivo. Further, the interaction between SINV and the closely related and functionally similar NRAMP1 protein has never been evaluated. Therefore, our OBJECTIVE in this study is to define the consequence of NRAMP2 utilization on SINV pathogenesis and to determine whether a similar role exists for NRAMP1. We HYPOTHESIZE that the mammalian NRAMP proteins are important determinants of SINV tropism and pathogenesis. To achieve our objective, we have proposed the following aims. In SPECIFIC AIM 1, we will analyze the role of NRAMP2 in host susceptibility to disease and virus tropism. We will achieve this aim using tissue- specific and inducible NRAMP2 knockout mouse models. In SPECIFIC AIM 2, we will investigate whether NRAMP1 functions as an additional entry receptor during SINV infection. We will use an in vitro model to overexpress NRAMP1 and define the relative utilization of mouse or human NRAMP 1 versus NRAMP2 by SINV. These studies will define the precise impact of mammalian NRAMP expression on SINV infection and disease. Successful completion of these aims could indicate that the NRAMP proteins are appropriate and novel therapeutic targets. The proposed study provides the applicant with an excellent source of training in virus-host interactions that impact alphavirus pathogenesis.