Mechanisms of PSGL-1 restriction of HIV virion infectivity

PSGL-1限制HIV病毒粒子感染性的机制

• 批准号: 10366051
• 负责人: YUNTAO WU
• 金额: $ 38.62万
• 依托单位: GEORGE MASON UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-04-01 至 2025-03-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10366051
• 关键词: Amino Acids; Binding; Biological Assay; CD4 Positive T Lymphocytes; Cell membrane; Cell surface; Cells; Clathrin; Dimerization; Disease remission; Down-Regulation; E-Selectin; Endothelium; Exclusion; Extracellular Domain; Glycoproteins; HIV; HIV Infections; HIV-1; Immune; Infection; L-Selectin; Leukocytes; Link; Lymphoid Cell; Mediating; Membrane; Mucins; Mutagenesis; Myeloid Cells; N-terminal; Natural Immunity; P-Selectin; P-selectin ligand protein; Pathogenesis; Pathway interactions; Phenotype; Process; Proteins; Receptor Cell; Residual state; Role; Site; Structure-Activity Relationship; Surface; Testing; Tissues; Ubiquitination; Viral; Viral Physiology; Viral reservoir; Virion; Virus Assembly; base; dimer; extracellular; glycosylation; migration; novel therapeutic intervention; particle; receptor; trafficking; tyrosine O-sulfate; ubiquitin-protein ligase; virus host interaction

Project Summary/Abstract Mechanisms of PSGL-1 restriction of HIV virion infectivity Restriction factors are an important component of host innate immunity. Studying the anti-HIV mechanisms of restriction factors is central to understanding virus-host interaction. These mechanisms may also offer new therapeutic strategies to inactivate viral reservoirs to achieve lasting HIV remission. Recently, we have identified a new HIV restriction factor, PSGL-1 (P-selectin glycoprotein ligand-1), that can inactivate the infectivity of HIV virions released from HIV producing cells. PSGL-1 is a dimeric mucin-like 120-KD glycoprotein that is primarily expressed on the surface of lymphoid and myeloid cells. PSGL-1 binds to P-, L-, and E-selectin, and mediates leukocyte tethering and rolling on endothelium for leukocyte migration into inflamed tissues. PSGL-1 is also an INF-γ-regulated factor involved in Th1-mediated anti-viral activity. Our preliminary mechanistic studies further revealed that PSGL-1 is incorporated into viral particles, which blocks HIV Env incorporation and disables the ability of virions to attach to target CD4 T cells for infection. In addition, we found that PSGL-1 is antagonized by Vpu and Nef through surface down-regulation. Based on these preliminary studies, we hypothesize that: (1) PSGL-1-mediated restriction of HIV infectivity involves its specific domains; (2) PSGL-1 restricts HIV infectivity likely through competitive exclusion of Env incorporation during viral assembly and steric hindrance of Env binding to cell receptors (3) Nef-mediated PSGL-1 down-regulation is likely achieved through linking PSGL-1 to components of clathrin-dependent trafficking pathways. In this application, we will pursue the following aims: Specific Aim 1 is to characterize PSGL-1 for inactivating HIV infectivity. We propose to identify PSGL-1 domains key to restricting HIV-1. We will determine the structure-function relationship of PSGL-1, defining the roles of PSGL-1 dimerization, N- terminal glycosylation and tyrosine sulfation, N-terminal decameric repeats, and the polybasic region in restricting HIV. Specific Aim 2 is to perform mechanistic studies of PSGL-1 inactivation of HIV viral infectivity. We hypothesized that PSGL-1 restricts HIV infectivity likely through two possible mechanisms: (1) competitive exclusion of Env incorporation during viral assembly; (2) steric hindrance of residual Env binding to cell receptors. We will test these two hypotheses to determine the mechanisms of action. Specific Aim 3 is to study the mechanism of Nef-mediated surface down-regulation of PSGL-1. We will identify functional domains of Nef and PSGL-1 for their involvement in PSGL-1 down-regulation. Nef-mediated PSGL-1 downregulation may facilitate viral spread in immune cells.

项目概要/摘要 PSGL-1限制HIV病毒粒子感染性的机制 限制因素是宿主先天免疫的重要组成部分。研究抗HIV机制 限制因素对于理解病毒与宿主相互作用至关重要。这些机制也可能提供新的 灭活病毒库以实现艾滋病毒持久缓解的治疗策略。最近，我们有 鉴定出一种新的 HIV 限制因子 PSGL-1（P-选择素糖蛋白配体-1），它可以使 HIV 失活 HIV产生细胞释放的HIV病毒粒子的感染性。 PSGL-1 是一种二聚粘蛋白样 120-KD 主要表达于淋巴和骨髓细胞表面的糖蛋白。 PSGL-1 结合 P-、L-、 和 E-选择素，并介导白细胞在内皮上的束缚和滚动，使白细胞迁移到 发炎的组织。 PSGL-1 也是一种 INF-γ 调节因子，参与 Th1 介导的抗病毒活性。我们的 初步机制研究进一步表明，PSGL-1 被纳入病毒颗粒中，从而阻断 HIV Env 掺入并禁用病毒颗粒附着到目标 CD4 T 细胞进行感染的能力。在 此外，我们发现PSGL-1通过表面下调而被Vpu和Nef拮抗。基于 根据这些初步研究，我们假设：(1) PSGL-1 介导的 HIV 感染性限制涉及其 特定领域； (2) PSGL-1可能通过竞争性排斥Env来限制HIV传染性 病毒组装过程中的掺入以及 Env 与细胞受体结合的空间位阻 (3) Nef 介导 PSGL-1 下调可能是通过将 PSGL-1 与网格蛋白依赖性成分连接来实现的 贩运途径。在此应用中，我们将追求以下目标： 具体目标 1 是表征 PSGL-1 用于灭活 HIV 感染性。我们建议确定限制 HIV-1 的关键 PSGL-1 结构域。我们 将确定 PSGL-1 的结构-功能关系，定义 PSGL-1 二聚化的作用，N- 末端糖基化和酪氨酸硫酸化、N 末端十聚重复序列以及多碱基区域 限制艾滋病毒。具体目标 2 是进行 PSGL-1 灭活 HIV 病毒的机​​制研究 传染性。我们假设 PSGL-1 可能通过两种可能的机制限制 HIV 感染性：(1) 在病毒组装过程中竞争性排除 Env 掺入； (2)残留Env结合的空间位阻 到细胞受体。我们将测试这两个假设以确定作用机制。具体目标 3 是 研究 Nef 介导的 PSGL-1 表面下调机制。我们将确定功能 Nef 和 PSGL-1 的结构域参与 PSGL-1 下调。 Nef介导的PSGL-1 下调可能会促进病毒在免疫细胞中的传播。