Roles of Macropinocytosis in HIV-1 infection of CD4+ T Cells

标题：巨胞饮在HIV-1感染CD 4 + T细胞中的作用 项目摘要： 进入宿主细胞是艾滋病病原体HIV-1复制周期的第一步。虽然受体 在病毒进入过程中病毒Env糖蛋白的结合和随后的病毒-细胞融合已经被 虽然已经详细描述了这些事件，但是这些事件的亚细胞位置仍有待确定。特别是，尽管 CD 4 + T淋巴细胞作为HIV-1天然宿主细胞类型的重要性，病毒粒子内吞作用的贡献 对HIV-1感染的CD 4 + T细胞仍然知之甚少。以前关于HIV-1进入T细胞的研究 主要集中在网格蛋白介导的内吞作用和细胞表面融合。然而，我们的团队最近 发现原代CD 4 + T细胞参与强大的巨胞饮作用，这是一种大规模的，不依赖网格蛋白的 内吞作用的形式。重要的是，我们的初步数据表明， 巨胞饮作用阻断HIV-1颗粒的内化和原代人的生产性感染 CD 4 + T细胞。相比之下，同样的治疗方法不会影响HIV感染常用的CD 4 + T细胞 线这些结果表明，巨胞饮细胞进入是迄今为止被忽视的HIV-1进入模式， 有助于感染原代人CD 4 + T细胞。有趣的是，我们的初步研究还表明， 在病毒内化完成后抑制巨胞饮作用也阻断了病毒编码的 基因，表明巨胞饮在生产性HIV感染中具有另一种后期作用， 从病毒内化。在当前的应用中，我们提出确定巨胞饮作用在 原代CD 4 + T细胞的生产性感染。我们的长期目标是充分描述细胞机制， 促进HIV-1感染，并利用获得的知识制定抗病毒策略。我们的中央 本申请中的假设是原代人CD 4 + T细胞中的巨胞饮作用有助于产生 感染作为主要的HIV-1进入途径和作为维持允许的免疫应答所必需的细胞功能。 病毒的环境。为了验证这一假设，我们计划确定：1）巨胞饮细胞在多大程度上 内化有助于HIV进入原代人CD 4 + T细胞; 2） Env-受体相互作用促进HIV-1巨胞饮作用; 3）巨胞饮体的影响 环境对HIV-1进入的影响;以及4）内化后巨胞饮功能的性质， 生产性感染本提案中概述的实验结果可能会填补知识空白 我们对HIV-1进入的理解，HIV-1复制周期的一个基本方面，并帮助我们发展 或改善靶向病毒进入和在CD 4 + T细胞中建立生产性感染的抗病毒策略。

Title: Roles of Macropinocytosis in HIV-1 infection of CD4+ T Cells Project Summary: Host cell entry is the first step in the replication cycle of HIV-1, the causative agent of AIDS. Although receptor binding of viral Env glycoprotein and subsequent virus-cell fusion during the virus entry process have been described in detail, subcellular locations of these events remain to be determined. In particular, despite the importance of CD4+ T lymphocytes as a natural host cell type for HIV-1, the contribution of virion endocytosis to HIV-1 infection of CD4+ T cells remains poorly understood. Previous studies of HIV-1 entry into T cells have largely focused on clathrin-mediated endocytosis and cell surface fusion. However, our team recently discovered that primary CD4+ T cells engage in robust macropinocytosis, a large-scale, clathrin-independent form of endocytosis. Importantly, our preliminary data indicate that pharmacological inhibition of macropinocytosis blocks both internalization of HIV-1 particles and productive infection in primary human CD4+ T cells. In contrast, the same treatment does not affect HIV infection of a commonly used CD4+ T cell line. These results suggest that the macropinocytic entry is a hitherto overlooked mode of HIV-1 entry that contributes to infection of primary human CD4+ T cells. Interestingly, our preliminary study also showed that inhibition of macropinocytosis after completion of virus internalization also blocks expression of virus-encoded genes, suggesting that macropinocytosis has another later role in productive HIV infection, which is separable from virus internalization. In the current application, we propose to determine the roles of macropinocytosis in productive infection of primary CD4+ T cells. Our long-term goal is to fully describe cellular mechanisms that promote HIV-1 infection and to use the obtained knowledge for developing antiviral strategies. Our central hypothesis in this application is that macropinocytosis in primary human CD4+ T cells contributes to productive infection as a major HIV-1 entry pathway and as a cellular function necessary for maintaining a permissive environment for the virus. To test this hypothesis, we plan to determine: 1) the extent to which macropinocytic internalization contributes to productive HIV entry into primary human CD4+ T cells; 2) the roles played by Env-receptor interactions in promoting HIV-1 macropinocytosis; 3) the influence of macropinosome environment on HIV-1 entry; and 4) the nature of post-internalization macropinocytosis function that promotes productive infection. The outcomes of the experiments outlined in this proposal will likely fill the knowledge gap in our understanding of HIV-1 entry, a fundamental aspect of the HIV-1 replication cycle, and help us develop or improve antiviral strategies that target virus entry and establishment of productive infection in CD4+ T cells.