Dissecting the alphavirus entry receptor NRAMP

描述（由申请方提供）：甲病毒与细胞受体的相互作用可能在决定病毒嗜性和驱动病毒诱导的疾病中发挥主要作用。然而，介导甲病毒进入的病毒受体知之甚少。使用辛德毕斯病毒的全基因组筛选将NRAMP鉴定为昆虫细胞中潜在的甲病毒进入受体。其他研究表明，NRAMP也是委内瑞拉马脑炎病毒的进入受体。此外，在哺乳动物细胞中，普遍表达的同源物NRAMP 2可以介导这些甲病毒的感染。我们的长期目标是剖析NRAMP在甲病毒感染性和发病机制中的作用，目的是制定对抗这些病原体的策略。我们将从病毒及其不同宿主的角度研究这种重要的相互作用，包括确定其他甲病毒是否使用NRAMP作为受体的研究，以及确定介导NRAMP结合的病毒糖蛋白区域的研究。由于哺乳动物有两个同源基因，NRAMP 1和NRAMP 2，我们还将测试NRAMP 1和NRAMP 2是否可以在功能上相互替代作为甲病毒进入受体，并测试这些分子中的一个或两个是否需要在不同谱系的原代细胞和体内甲病毒感染。我们将利用我们已经开发的强大的检测方法来研究甲病毒在昆虫和哺乳动物细胞中的进入和感染，并将这些研究扩展到小鼠和成年苍蝇，以探索NRAMPs在病毒发病机制和传播中的作用。我们的中心假设是，解剖这些医学上重要的虫媒病毒与其受体的相互作用将揭示机制，这将有助于开发针对这些未充分研究的病原体的抗病毒治疗，这些病原体没有疫苗或治疗方法。 公共卫生相关性：甲病毒是人类疾病的重要原因，了解甲病毒受体如何调节病毒嗜性和发病机制可能会导致开发针对这些人类病原体的新疗法。本提案中概述的研究将评估NRAMP 1和NRAMP 2作为甲病毒在昆虫和脊椎动物宿主中的进入受体的作用，最终目标是阐明NRAMP/甲病毒相互作用如何影响病毒发病机制。

DESCRIPTION (provided by applicant): Alphavirus interactions with cellular receptors are likely to play a major role determining viral tropism and driving virus-induced disease. However, the viral receptors that mediate alphavirus entry are poorly understood. A genome wide screen using Sindbis virus identified NRAMP as a potential alphavirus entry receptor in insect cells. Additional studies suggest that NRAMP is also an entry receptor for Venezuelan Equine Encephalitis virus. Furthermore, in mammalian cells the ubiquitously expressed homolog, NRAMP2, can mediate infection of these alphaviruses. Our long-term goal is to dissect the role of NRAMPs in infectivity and pathogenesis of alphaviruses with the goal of developing strategies to combat these pathogens. We will study this important interaction from both the perspective of the viruses and their varied hosts, including studies to determine whether additional alphaviruses use NRAMP as a receptor and to define the regions of the viral glycoproteins that mediate NRAMP binding. Since mammals have two homologous genes, NRAMP1 and NRAMP2, we will also test whether NRAMP1 and NRAMP2 can functionally substitute for one another as alphavirus entry receptors and test whether one or both of these molecules is required for alphavirus infection in primary cells from diverse lineages and in vivo. We will take advantage of powerful assays that we have developed to study alphavirus entry and infection both in insect and mammalian cells and extend these studies to mice and adult flies to explore the role of NRAMPs in viral pathogenesis and spread. Our central hypothesis is that dissecting the interactions of these medically important arboviruses with their receptor will reveal mechanisms that will aid in the development of antiviral treatments against these understudied pathogens for which there are no vaccines or therapeutics. PUBLIC HEALTH RELEVANCE: Alphaviruses are a significant cause of human disease and understanding how alphavirus receptors regulate viral tropism and pathogenesis is likely to result in the development of new therapies against these human pathogens. The studies outlined in this proposal will evaluate the role of NRAMP1 and NRAMP2 as entry receptors for alphaviruses in insects and vertebrate hosts, with the ultimate goal of elucidating how NRAMP/alphavirus interactions impact viral pathogenesis.