IFITM-mediated Inhibition of HIV Infection and Viral Countermeasures

描述（由申请人提供）：干扰素（IFN）在宿主对病毒感染的内在免疫中起核心作用，其潜在机制尚不明确。为了实现这一目标，我们最近发现干扰素诱导的跨膜（IFITM）蛋白深刻地抑制了许多包膜病毒（包括HIV-1）的膜融合和感染。有趣的是，我们发现，虽然人类IFITM2和IFITM3阻碍HIV- 1 （BH10）的进入，但人类IFITM1损害病毒的传染性。值得注意的是，BH10 HIV-1的长时间培养导致HIV-1 Env中出现突变，使病毒对IFITM1抑制产生抗性，这表明ifitm可能在功能上作用于HIV-1 Env并降低病毒的传染性。这个R01项目的目标是确定IFITM蛋白抑制HIV复制的不同步骤以及病毒拮抗的机制。目的1将探讨IFITM蛋白如何抑制HIV-1的进入。我们将使用新的细胞-细胞融合和单病毒融合技术来验证IFITM2和IFITM3抑制半融合和孔扩张的假设。目标2将重点关注IFITM蛋白，特别是IFITM1如何降低HIV-1的传染性。我们将验证IFITM蛋白被整合到HIV-1颗粒中并在功能上灭活HIV-1 Env活性的中心假设。目的3将描述HIV-1对ifitm的拮抗作用，特别是HIV-1 Env在这一过程中的可能作用。总的来说，这个项目的结果将为ifitm的作用机制提供重要的见解，并将有助于开发针对HIV-1感染的新型抗病毒药物。

DESCRIPTION (provided by applicant): Interferon (IFN) plays a central role in host intrinsic immunity to viral infection, the underlying mechanism of which remains poorly defined. Towards this goal, we have recently shown that interferon-induced transmembrane (IFITM) proteins profoundly inhibit the membrane fusion and infection of a number of enveloped viruses, including HIV-1. Interestingly, we found that, while human IFITM2 and IFITM3 impede HIV- 1 (BH10) entry, human IFITM1 impairs viral infectivity. Notably, the prolonged culture of BH10 HIV-1 led to the emergence of mutations in HIV-1 Env that render the virus resistant to IFITM1 inhibition, suggesting that IFITMs may functionally act on HIV-1 Env and diminish viral infectivity. The goal of this R01 project is to determine the mechanisms by which IFITM proteins inhibit distinct steps of HIV replication, as well as viral antagonisms. Aim 1 will address how IFITM proteins inhibit HIV-1 entry. We will use novel cell-cell fusion and single virus fusion techniques to test the hypothesis that both hemifusion and pore expansion are inhibited by IFITM2 and IFITM3. Aim 2 will focus on how IFITM proteins, especially IFITM1, diminish HIV-1 infectivity. We will test the central hypothesis that IFITM proteins are incorporated into HIV-1 particles and functionally inactivate HIV-1 Env activity. Aim 3 will characterize HIV-1 antagonisms against IFITMs, particularly the possible role of HIV-1 Env in this process. Collectively, results from this project will provide critical insights into the mechanisms of actio of IFITMs, and will aid in the development of novel antiviral agents against HIV-1 infection.