MECHANISM OF REGULATION OF HIV-1 INFECTION BY CHEMOKINES

趋化因子调节 HIV-1 感染的机制

• 批准号: 6534118
• 负责人: Helena Schmidtmayerova
• 金额: $ 25.7万
• 依托单位: FEINSTEIN INSTITUTE FOR MEDICAL RESEARCH
• 依托单位国家: 美国
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-09-01 至 2004-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6534118
• 关键词: G protein; HIV infections; T lymphocyte; biological signal transduction; chemokine; cytokine receptors; human immunodeficiency virus 1; immunofluorescence technique; macrophage; protein localization; receptor expression; second messengers; tissue /cell culture; virus replication

This is the second re-submission of the PI's first independent support request in which we propose to study the molecular mechanisms involved in beta-chemokine regulation of HIV-1 infection in primary macrophages (versus lymphocytes). The members of the chemokine receptor family, CXCR4 and CCR5, have been shown to act as fusion cofactors for HIV-1 T-tropic (X4) and M-tropic (R5) strains, respectively. The discovery in humans of the association of a homozygous defective CCR5 allele (CCR5 delta32) with resistance to HIV-1 infection demonstrated the importance of CCR5 in HIV-1 transmission. Furthermore, this observation suggested that targeting the HIV-1-CCR5 interaction may provide a means of interfering with HIV-1 infection. However, while a large body of work has demonstrated that the natural ligands of CCR5 (beta-chemokines; MIP-1alpha, MIP-1beta, and RANTES) inhibit HIV-1 replication in lymphocytes, our results demonstrated an enhancing rather than an inhibitory effect of beta-chemokines on HIV-1 replication in primary macrophages. We have begun to address the mechanisms which underlie this phenomenon and our preliminary data suggest that in macrophages beta-chemokine-treatment induces only transient inhibition of HIV-1 entry followed by upregulation of virus replication (inhibition of HIV-1 replication in lymphocytes combines sustained inhibition at the entry and post-entry level). Since macrophages are an important target of HIV-1 during virus transmission, a major goal of this proposal is to define the mechanisms which facilitate upregulation of HIV-1 replication in beta-chemokine-treated macrophages. We propose to characterize the regulation of CCR5 expression by beta-chemokines, and to establish whether altered expression of CCR5 in macrophages (as compared to lymphocytes) contributes to the observed phenomenon. Further, we propose to identify G proteins and downstream effectors activated by beta-chemokine binding to CCR5 receptors expressed in macrophages, and to characterize their effects on the signaling pathways involved in HIV-1 replication in macrophages (lymphocytes will be assayed in parallel for comparison). Together, these proposed studies should provide new insights into the mechanisms by which beta-chemokines regulate HIV-1 infection in primary macrophages, an important target of the virus during transmission of HIV-1 infection, and thus contribute to a better understanding of the unique aspects of AIDS pathogenesis.

这是 PI 第一次独立支持请求的第二次重新提交，在该请求中，我们建议研究初级巨噬细胞（相对于淋巴细胞）中 HIV-1 感染的 β 趋化因子调节所涉及的分子机制。 趋化因子受体家族的成员 CXCR4 和 CCR5 已被证明分别充当 HIV-1 T 向性 (X4) 和 M 向性 (R5) 毒株的融合辅助因子。 在人类中发现纯合缺陷 CCR5 等位基因 (CCR5 delta32) 与 HIV-1 感染抵抗力之间的关联，证明了 CCR5 在 HIV-1 传播中的重要性。 此外，这一观察结果表明，针对 HIV-1-CCR5 相互作用可能提供一种干扰 HIV-1 感染的方法。然而，虽然大量工作已证明 CCR5（β 趋化因子；MIP-1α、MIP-1β 和 RANTES）的天然配体抑制淋巴细胞中的 HIV-1 复制，但我们的结果表明 β 趋化因子对原代巨噬细胞中的 HIV-1 复制具有增强作用，而不是抑制作用。 我们已经开始解决这一现象背后的机制，我们的初步数据表明，在巨噬细胞中，β-趋化因子治疗仅诱导短暂抑制 HIV-1 进入，随后上调病毒复制（淋巴细胞中 HIV-1 复制的抑制结合了进入和进入后水平的持续抑制）。 由于巨噬细胞是 HIV-1 在病毒传播过程中的重要目标，因此该提案的一个主要目标是确定促进经 β-趋化因子处理的巨噬细胞中 HIV-1 复制上调的机制。 我们建议表征 β-趋化因子对 CCR5 表达的调节，并确定巨噬细胞（与淋巴细胞相比）中 CCR5 表达的改变是否有助于观察到的现象。此外，我们建议鉴定由与巨噬细胞中表达的 CCR5 受体结合的 β-趋化因子激活的 G 蛋白和下游效应子，并表征它们对巨噬细胞中 HIV-1 复制所涉及的信号通路的影响（将平行测定淋巴细胞以进行比较）。 总之，这些拟议的研究应该为 β 趋化因子调节原代巨噬细胞中 HIV-1 感染的机制提供新的见解，原代巨噬细胞是 HIV-1 感染传播过程中病毒的重要目标，从而有助于更好地了解艾滋病发病机制的独特方面。