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固有免疫中起着核心作用，其潜在机制仍不清楚。为了实现这一目标，我们最近已经表明，干扰素诱导的跨膜（IFITM）蛋白深刻抑制膜融合和感染的一些包膜病毒，包括HIV-1。有趣的是，我们发现，虽然人IFITM 2和IFITM 3阻碍HIV- 1（BH 10）进入，但人IFITM 1削弱病毒感染性。值得注意的是，BH 10 HIV-1的长期培养导致HIV-1 Env中出现突变，使病毒对IFITM 1抑制具有抗性，这表明IFITM可能在功能上作用于HIV-1 Env并降低病毒感染性。这个R 01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作用的机制。目标1将解决IFITM蛋白如何抑制HIV-1进入。我们将使用新的细胞-细胞融合和单病毒融合技术来测试半融合和孔扩张都被IFITM 2和IFITM 3抑制的假设。目标2将重点关注IFITM蛋白，特别是IFITM 1，如何降低HIV-1的感染性。我们将测试IFITM蛋白被纳入HIV-1颗粒和功能性抑制HIV-1 Env活性的中心假设。目标3将描述HIV-1拮抗IFITMs的特性，特别是HIV-1 Env在此过程中可能的作用。总的来说，该项目的结果将为IFITM的作用机制提供重要的见解，并将有助于开发新的抗HIV-1感染的抗病毒剂。

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.