Mechanism of HIV-1 attachment to dendritic cells

描述(申请人提供)：人类免疫缺陷病毒1型(HIV-1)是人类艾滋病的病原体。树突状细胞(DC)是病毒传播到幼稚宿主后早期被病毒靶向的初始细胞类型之一，在建立生产性病毒感染和在体内传播HIV-1方面发挥关键作用。虽然DC本身总是被感染的，但DC捕获的HIV-1颗粒会有效地传播到CD4+T细胞，这是HIV-1反式感染的一种机制。尽管进行了广泛的研究，但HIV-1颗粒入侵DC的机制仍然难以捉摸。一些树突状细胞特异性的HIV-1附着因子被提出来解释DC介导的HIV-1包膜糖蛋白gp120依赖的病毒捕获。但是，有针对性地中和任何或所有这些先前提出的DC中的HIV-1附着因子，并不能抑制病毒捕获或捕获的HIV-1颗粒从DC向T细胞的传播，提示DC中存在gp120非依赖的病毒捕获机制(S)，这对建立HIV-1反式感染至关重要。我们认为HIV-1可以通过表达在病毒颗粒膜脂双层中的糖鞘糖脂与DC结合，并且这些与gp120无关的病毒颗粒可以被传递到CD4+T细胞。本项目的目标是确定HIV-1gp120非依赖的、糖鞘糖脂依赖的DC结合机制的性质。我们将尝试使用两种独立的实验策略来鉴定HIV-1颗粒表面的糖鞘糖脂，这些糖脂介导与DC的附着。我们将利用基于siRNA的有针对性的方法在病毒产生者水平选择性地消耗GSLS，以确定病毒颗粒附着到DC所需的GSLS的类别。接下来，我们将使用基于比较质谱学的脂质组学策略来确定介导病毒颗粒附着的特定GSL。最后，我们将确定病毒颗粒膜上存在的GSLs是否对将HIV-1颗粒靶向DC介导的T细胞传播途径至关重要。了解这种情况发生的机制将提供有关HIV-树突状细胞相互作用途径中的关键步骤的信息，并有助于深入了解树突状细胞在HIV-1发病机制中的作用。此外，阐明HIV-1与树突状细胞结合的这种机制可能为针对HIV-1生命周期早期阶段的抗病毒药物的设计提供新的靶点。公共卫生相关性：该项目的目的是确定人类免疫缺陷病毒1型(S)与树突状细胞结合的机制(S)，这是病毒在体内建立感染和传播的关键步骤。对HIV-1致病过程中这一关键步骤的详细了解可能会导致开发抗病毒药物，如防止将HIV-1传播给幼稚宿主的杀微生物剂。

DESCRIPTION (provided by applicant): Human immunodeficiency virus type 1 (HIV-1) is the causative agent of AIDS in humans. Dendritic cells (DCs) are one of the initial cell types that are targeted by the virus early following virus transmission to a naive host, and play a critical role in the establishment of productive virus infection and dissemination of HIV-1 in vivo. While DCs themselves are invariably infected, HIV-1 particles captured by DCs are efficiently transmitted to CD4+ T cells, a mechanism of HIV-1 trans infection. Though studied extensively, the mechanisms by which HIV-1 particles invade DCs have remained elusive. A number of dendritic cell-specific HIV-1 attachment factors have been proposed to account for DC-mediated virus capture in a HIV-1 envelope glycoprotein gp120 dependent manner. But targeted neutralization of any or all of these previously proposed HIV-1 attachment factors in DCs, fails to inhibit virus capture or transmission of captured HIV-1 particles from DCs to T cells, suggesting the existence of gp120-independent virus capture mechanism(s) in DCs that is crucial for the establishment of HIV-1 trans infection. We propose that HIV-1 can bind DCs using glycosphingolipids expressed in the lipid bilayer of the virus particle membrane and that these virus particles bound independently of gp120 can be transmitted to CD4+ T cells. The goal of this project is to identify the nature of the HIV-1 gp120-independent, glycosphingolipid-dependent mechanism of binding to DCs. We will attempt to identify the glycosphingolipids on the HIV-1 particle surface that mediate attachment to DCs using two independent experimental strategies. We will utilize a targeted siRNA-based approach to selectively deplete GSLs in the virus-producer levels to determine the class of GSLs necessary for virus particle attachment to DCs. We will next use comparative mass spectrometry based lipidomics strategy to identify the specific GSL that mediates virus particle attachment. Finally, we will determine if GSLs present in the virus particle membrane are crucial for targeting HIV-1 particles to the DC-mediated T cell trans infection pathway. Understanding the mechanism by which this occurs will provide information about a key step in the HIV - dendritic cell interaction pathway, and provide insights into the role of dendritic cells in HIV-1 pathogenesis. Furthermore, elucidation of this mechanism of HIV-1 attachment to DCs might provide novel targets for design of anti-virals that specifically target an early step in the HIV-1 life cycle. PUBLIC HEALTH RELEVANCE: The aim of this project is to identify the mechanism(s) by which human immunodeficiency virus type 1 (HIV-1) can bind dendritic cells, a critical step in the establishment of infection and dissemination of virus in vivo. A detailed understanding of this crucial step in HIV-1 pathogenesis could lead to the development of anti-virals such as microbicides that prevent transmission of HIV-1 to a naive host.