Mechanism of HIV-1 attachment to dendritic cells

描述（由申请人提供）：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）是病毒传播到初始宿主后早期被病毒靶向的初始细胞类型之一，在体内建立多产的病毒感染和HIV-1传播中起关键作用。虽然dc本身总是被感染，但dc捕获的HIV-1颗粒有效地传播到CD4+ T细胞，这是HIV-1反式感染的一种机制。尽管研究广泛，但HIV-1颗粒侵入dc的机制仍然难以捉摸。许多树突状细胞特异性HIV-1附着因子已被提出以HIV-1包膜糖蛋白gp120依赖的方式解释dc介导的病毒捕获。但是，在dc中靶向中和任何或所有这些先前提出的HIV-1附着因子，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，这表明dc中存在不依赖gp120的病毒捕获机制，这对于HIV-1反式感染的建立至关重要。我们提出HIV-1可以通过在病毒颗粒膜脂质双分子层中表达的鞘糖脂结合树突状细胞，并且这些独立于gp120结合的病毒颗粒可以传播到CD4+ T细胞。该项目的目标是确定HIV-1不依赖于gp120的、依赖于鞘糖脂的与dc结合的机制的性质。我们将尝试使用两种独立的实验策略来鉴定HIV-1颗粒表面介导DCs附着的鞘糖脂。我们将利用一种靶向sirna的方法，选择性地耗尽病毒产生者水平上的GSLs，以确定病毒颗粒附着在dc上所需的GSLs类别。接下来，我们将使用基于比较质谱的脂质组学策略来鉴定介导病毒颗粒附着的特异性GSL。最后，我们将确定存在于病毒颗粒膜中的GSLs是否对将HIV-1颗粒靶向到dc介导的T细胞转感染途径至关重要。了解这种发生的机制将为HIV-树突状细胞相互作用途径的关键步骤提供信息，并为树突状细胞在HIV-1发病机制中的作用提供见解。此外，阐明HIV-1粘附于dc的这一机制可能为设计特异性靶向HIV-1生命周期早期阶段的抗病毒药物提供新的靶点。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（HIV-1）结合树突状细胞的机制，这是建立病毒在体内感染和传播的关键步骤。对HIV-1发病机制中这一关键步骤的详细了解可能会导致杀菌剂等抗病毒药物的开发，以防止HIV-1传播给幼稚的宿主。

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.