HIV-1 Env conformation and tropism in brain colonization and neuroAIDS

高效结合CD4的高度嗜麦性HIV-1R5基因与HIV神经系统疾病相关 包括艾滋病毒相关性痴呆(HAD)。然而，我们对环境的性质和决定因素的知识 这种定植大脑并进化成高度嗜麦性、神经毒性的变种是不完整的。如果没有这个，我们 不会完全了解嗜神经性HIV-1毒株是如何以及在哪里产生并发展成神经毒力形式的。 我们的初步数据显示，R5env来源于无或仅有脑组织的受试者 轻度神经认知疾病(N/MC)与HAD脑病变相比，以非嗜中性为主。 这一数据表明，艾滋病毒进入脑组织并不需要嗜麦性，并打开了一种可能性 在嗜麦性和神经毒性变异株进化之前，艾滋病毒被感染的T细胞携带进来。环境决定因素 HAD的嗜麦性包括CD4b内或其近端的残基。然而，单一的通用 嗜麦性的环境决定因素尚未确定，在gp120的不同部分，如V1V2中存在残基 而V3环则对嗜麦性有调节作用。这些残基可能会增加蛋白质的亲和力 (1)直接通过接触残基的变化或(2)通过改善获得 CD4或增强CD4诱导的构象变化。我们最近建立了一个三聚体Env：CD4结合 实验表明，来自大脑的嗜Mac环境三聚体有效地结合了CD4，而非嗜Mac环境三聚体则不能。 我们将使用这一方法和其他分析方法来研究免疫和免疫系统中环境蛋白的构象和功能的变化。 N/MC和HAD受试者的脑组织。我们的假设是，HAD是由环境变量的进化决定的 与CD4的亲和力更高，(1)携带不那么紧密封闭的环境三聚体，具有更多暴露的CD4bs，(2)是 更容易被CD4触发；(3)介导有效的巨噬细胞感染。我们提出三个目标： 目的1：分析N/MC患者免疫和脑组织中HIV-1的复制和趋向性。我们会 确定从N/MC受试者脑中恢复的ENV是否来自活跃复制的病毒和 它们在多大程度上是向Mac的。 目的2：研究N/MC中Env构象、趋向性、受体相互作用和神经毒性的变化。 有受试者。我们将研究免疫和大脑之间环境三聚体的构象和功能的变化。 N/MC组织和HAD受试者。 目的3：确定gp120和gp41中调控嗜麦性的决定因素，并评估它们对 Env的构象和功能。我们将确定与(1)相关的环境行列式和属性 脑组织中的定植和病毒复制；(2)神经毒力和神经艾滋病。我们将提供新的 帮助制定战略以识别有神经艾滋病风险的艾滋病毒+受试者的见解和治疗方法 攻击中枢神经系统中持续存在的艾滋病毒。

Highly mac-tropic HIV-1 R5 Envs that efficiently bind CD4 are associated with HIV neurological disease including HIV associated dementia (HAD). However, our knowledge of the properties and determinants of Envs that colonize brain and evolve into highly mac-tropic, neurovirulent variants are incomplete. Without this, we will not fully understand how and where neurotropic HIV-1 strains arise and develop into neurovirulent forms. Our preliminary data shows that R5 Envs derived from brain tissue of subjects without or with only minor neurocognitive disease (N/MCs) were mainly non-mac-tropic compared to those in HAD brain. This data suggests that mac-tropism is not required for HIV to enter brain tissue and opens up the possibility that HIV is carried in by infected T-cells, before mac-tropic and neurovirulent variants evolve. Env determinants that confer mac-tropism in HAD include residues within or proximal to the CD4bs. However, a single universal Env determinant of mac-tropism has not been identified and residues in different parts of gp120 e.g. the V1V2 and V3 loops were shown to modulate mac-tropism. These residues presumably increase the affinity of the Env trimer for CD4 either (1) directly via changes in contact residues or (2) indirectly by improving access to CD4 or enhancing CD4-induced conformational changes. We recently established a trimeric Env: CD4 binding assay, which shows mac-tropic Env trimers from brain bind CD4 efficiently, while non-mac-tropic Envs don't. We will use this and other assays to investigate how Env conformation and function varies in immune and brain tissue of N/MC and HAD subjects. Our hypothesis is that HAD is determined by the evolution of Envs with a higher affinity for CD4, that (1) carry less tightly closed Env trimers with a more exposed CD4bs, (2) are more easily triggered by CD4 and (3) mediate efficient macrophage infection. We propose 3 aims: Aim 1: To analyze HIV-1 replication and tropism in immune and brain tissue of N/MC subjects. We will establish whether envs recovered from brain of N/MC subjects are derived from actively replicating virus and the extent they are mac-tropic. Aim 2: To establish how Env conformation, tropism, receptor interactions and neurotoxicity vary in N/MC and HAD subjects. We will investigate how Env trimer conformation and function vary between immune and brain tissue of N/MC and HAD subjects. Aim 3: To identify determinants in gp120 and gp41 that modulate mac-tropism and evaluate their impact on Env conformation and function. We will identify Env determinants and properties associated with (1) colonization and viral replication in brain tissue and (2) neurovirulence and neuroAIDS. We will provide new insights to help develop strategies to identify HIV+ subjects at risk of neuroAIDS and `cure' approaches to attack persistent HIV in the CNS.