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（Dendritic cells，DC）是HIV-1病毒感染宿主后早期靶向的细胞类型之一，在HIV-1病毒感染和传播过程中起着重要作用。虽然DC本身总是被感染，但DC捕获的HIV-1颗粒有效地传递到CD 4 + T细胞，这是HIV-1反式感染的机制。虽然广泛研究，HIV-1颗粒侵入DC的机制仍然难以捉摸。已经提出了许多树突状细胞特异性HIV-1附着因子以HIV-1包膜糖蛋白gp 120依赖性方式解释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，表明DC中存在对HIV-1反式感染的建立至关重要的gp 120非依赖性病毒捕获机制。我们建议，HIV-1可以结合DC使用的鞘糖脂表达的病毒颗粒膜的脂质双层，这些病毒颗粒结合独立的gp 120可以传输到CD 4 + T细胞。该项目的目标是确定HIV-1 gp 120独立的、鞘糖脂依赖的与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颗粒表面介导与DC附着的鞘糖脂。我们将利用靶向siRNA为基础的方法，选择性地耗尽GSL的病毒生产水平，以确定病毒颗粒附着到DC所需的GSL的类别。我们接下来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，我们将确定是否GSL存在于病毒颗粒膜是至关重要的靶向HIV-1颗粒的DC介导的T细胞的反式感染途径。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关键步骤的信息，并提供对树突状细胞在HIV-1发病机制中作用的见解。此外，阐明HIV-1附着于DC的这种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：本项目的目的是确定人类免疫缺陷病毒1型（HIV-1）与树突细胞结合的机制，这是病毒在体内建立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抗病毒药物的开发，如防止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.