Host Cell Factors and AIDS Pathogenesis

宿主细胞因素与艾滋病发病机制

• 批准号: 7622724
• 负责人: GHALIB ABBAS ALKHATIB
• 金额: $ 38.5万
• 依托单位: INDIANA UNIV-PURDUE UNIV AT INDIANAPOLIS
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-05-15 至 2010-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7622724
• 关键词: Acquired Immunodeficiency Syndrome; Apoptosis; Biological; Biological Process; Bypass; C-terminal; CCR5 gene; CD4 Positive T Lymphocytes; CXCR4 gene; Cells; Characteristics; Chronic; Disease; Drug Design; Excision; Future; Glycoproteins; Goals; HIV; HIV Envelope Protein gp120; HIV Infections; HIV-1; Heterodimerization; Homosexuals; Individual; Induction of Apoptosis; Infection; Knowledge; Mediating; Molecular; Mutation; Nature; Pathogenesis; Patients; Pattern Recognition; Peptides; Peripheral Blood Mononuclear Cell; Phenotype; Physiologic pulse; Play; Production; Promoter Regions; Protein Deficiency; Proteins; Public Health; Reagent; Recombinants; Research; Resistance; Role; Sampling; Signal Pathway; Surface; Tail; Translations; Viral; Viral Load result; Virus; base; env Glycoproteins; in vivo; insight; neutralizing antibody; novel; protective effect; protein expression; public health relevance; receptor; research study; resistance mechanism; therapeutic target; transmission process; vaccine development; virology

DESCRIPTION (provided by applicant): A lack of CCR5 expression is associated with resistance to HIV-1 infection. This deficiency is due to homozygosity of a 32bp deletion in the CCR5 gene (CCR5 32). Several CCR5 32 individuals lacking CCR5 expression (CCR5-/-) yet HIV-1-seropositive have been identified. How the virus overcomes the CCR5 32 protective effects have not been delineated and we have investigated this in six HIV+ CCR5-/- patients. We demonstrated that peripheral blood mononuclear cells (PBMCs) isolated from exposed/uninfected (EU) CCR5- /- individuals express a truncated CCR5 32 protein. In contrast, four exposed/infected (EI) CCR5-/- patients lack expression of the CCR5 32 protein and two others expressed low levels. Pulse-chase experiments demonstrated instability of the protein in three HIV+CCR5-/- individuals. Another two had a mutation in the promoter region that was associated with low translation of the CCR5 32 protein. The lack or low CCR5 32 protein expression was associated with increased surface CXCR4. However, our results indicate that the loss of resistance in the HIV+CCR5-/- patients cannot be solely due to their increased CXCR4 levels. Expression of recombinant CCR5 32 protein restored the protective effect in three HIV+ CCR5-/- PBMC samples but failed to restore the protective effect in samples from another three HIV+ CCR5-/- individuals. Two potential mechanisms are proposed to be investigated for the loss of CCR5 32 expression in HIV+CCR5-/- subject; 1) a trans effect caused by the infecting virus or 2) a cis host effect that ultimately resulted in the creation of new signaling pathways and the loss of the resistance phenotype. We found that envelope glycoproteins (Envs) cloned from two independent CCR5-/- patients showed expanded coreceptor usage. We hypothesize that the primary HIV-1 strains isolated from the HIV+CCR5-/- individuals have unique structural determinants that allowed them to bypass the protective effect of the CCR5 32 mutation. Rapid CD4+ T cell loss despite mild viral load is characteristic of the chronic infection of these HIV+CCR5-/- patients. The novelty of our approach lay in the unique nature of these primary isolates to infect and replicate in CCR5-/- cells in vivo. The overall goal of this proposal is to define the molecular basis for the loss of the CCR5 32 protective effect. To do this we will characterize primary HIV-1 isolates from CCR5-/- patients, evaluating Env fusogenicity, apoptosis induction ability, coreceptor recognition patterns, and we will determine the role of the novel 31 residues at the C-terminus of CCR5 32 protein. PUBLIC HEALTH RELEVANCE: This application proposes to investigate the kind of HIV viruses harbored in infected homosexual individuals. Since HIV is the virus that causes acquired immunodeficiency syndrome (AIDS), the basic knowledge of these HIV viruses will provide an important new insight into AIDS pathogenesis. This project is very relevant to public health since the results of the proposed research will provide new mechanistic approaches to the design of drugs that block HIV-1 infection.

描述（由申请人提供）：缺乏CCR5表达与对HIV-1感染的抗性有关。这种缺陷是由于CCR5基因中32bp缺失的纯合性（CCR5 32）。已经鉴定出了几个缺乏CCR5表达（CCR5 - / - ）但HIV-1序列阳性的CCR5 32个个体。该病毒如何克服CCR5 32保护作用尚未划定，我们已经在六名HIV+ CCR5 - / - 患者中进行了研究。我们证明了外周血单核细胞（PBMC）从暴露 /未感染（EU）CCR5- / - 个体中分离出来，表达截短的CCR5 32蛋白。相反，四个暴露/感染（EI）CCR5 - / - 患者缺乏CCR5 32蛋白的表达，另外两种表达低水平。脉搏追踪实验表明，在三个HIV+CCR5 - / - 个体中蛋白质的不稳定。另外两个在启动子区域中有一个突变，与CCR5 32蛋白的低翻译相关。缺乏或低CCR5 32蛋白表达与表面CXCR4增加有关。但是，我们的结果表明，HIV+CCR5 - / - 患者的耐药性损失不能仅仅是由于其CXCR4水平升高。重组CCR5 32蛋白的表达恢复了三个HIV+ CCR5 - / - PBMC样品中的保护作用，但未能恢复另外三个HIV+ CCR5 - / - 个体的样品中的保护作用。建议研究两种潜在的机制，以使HIV+CCR5 - / - 受试者中CCR5 32表达的丧失； 1）由感染病毒引起的反式效应或2）CIS宿主效应最终导致创建新的信号通路和电阻表型的丧失。我们发现，从两名独立的CCR5 - / - 患者克隆的包膜糖蛋白（ENVS）显示出使用的colecector使用量扩大。我们假设从HIV+CCR5 - / - 个体分离出的主要HIV-1菌株具有独特的结构决定因素，使他们能够绕过CCR5 32突变的保护作用。尽管病毒负荷轻度，快速CD4+ T细胞损失是这些HIV+ CCR5 - / - 患者的慢性感染的特征。我们方法的新颖性在于这些主要分离株的独特性质，以在体内感染和复制在CCR5 - / - 细胞中。该提案的总体目标是定义丢失CCR5 32保护效应的分子基础。为此，我们将表征来自CCR5 - / - 患者的原发性HIV-1分离株，评估ENV融合性，凋亡诱导能力，良好受体识别模式，我们将确定新型31个残基在CCR5 32蛋白的C-末端的作用。公共卫生相关性：本申请提议调查受感染同性恋者所藏有的艾滋病毒病毒。由于HIV是引起获得性免疫缺陷综合征（AIDS）的病毒，因此这些HIV病毒的基本知识将为AIDS发病机理提供重要的新见解。该项目与公共卫生非常相关，因为拟议的研究结果将为阻断HIV-1感染的药物设计提供新的机械方法。