Retinoid Repression of HIV Through Chromatin Remodeling

描述(申请人提供)：HIV-1感染导致免疫 宿主的反应，被认为可以解决高水平的病毒血症 在感染的急性期被发现。慢性感染是可能的 因为HIV-1的进化是为了逃避宿主的免疫反应。一种战略 HIV-1所使用的免疫逃避是建立潜伏感染。维生素 A类代谢物，包括全反式维甲酸(RA)，是天然的抑制物 并可能在HIV1的建立和维持中发挥作用 病毒潜伏期。RA持续抑制HIV-1在原发区域的复制 受细胞因子刺激的巨噬细胞在正常情况下 感染的巨噬细胞驻留在活体内的局部部位的浓度 这项提案的总体目标是了解RA如何抑制HIV-1 并确定这一过程在潜伏期、RA抑制中的作用 HIV-1的表达与抑制重塑和 位于核小体起始点的组蛋白H4的高乙酰化 HIV-1转录。这些结果，以及镇压需要 新的细胞蛋白质合成，支持RA诱导因子的假设 与病毒启动子特异性结合，从而防止 染色质重塑。这项提议的目标是检验这一假设。 有两个具体目标。目标I的目标是评估RA作为 细胞因子激活的原代巨噬细胞中HIV-1复制的抑制因子和 以确定抑制是否需要诱导特定的细胞 信号通路。目标2的目标是评估RA作为 HIV-1染色质结构在已建立的细胞系和 原生细胞。RA诱导的核小体结合的改变和 组蛋白的翻译后修饰将在体内使用 核小体图谱和足迹以及染色质免疫沉淀 化验。这些目标是描绘分子的长期目标的一部分。 维甲酸介导的抑制机制及其治疗方法的确定 潜力。

DESCRIPTION (provided by applicant): HIV-1 infection leads to an immune response in the host that is thought to resolve the high levels of viremia found during the acute phase of infection. Chronic infections are possible because HIV-1 has evolved to evade the host immune response. One strategy of immune evasion used by HIV-1 is the establishment of latent infections. Vitamin A metabolites, including all-trans retinoic acid (RA), are natural repressors of HIV1 expression and may play a role in the establishment and maintenance of viral latency. RA consistently represses HIV-1 replication in primary macrophages that are stimulated by cytokines normally found in high concentrations at local sites, where infected macrophages reside in viva The overall goals of this proposal are to understand how RA represses HIV-1 expression and to determine the role of this process in latency, RA repression of HIV-1 expression is associated with an inhibition in the remodeling and histone H4 hyperacetylation of a nucleosome positioned at the start site of HIV-1 transcription. These results, and the finding that repression requires new cellular protein synthesis, support the hypothesis that RA induces a factor that specifically associates with the viral promoter and thereby prevents chromatin remodeling. The goal of this proposal is to test this hypothesis. There are two specific aims. The goal of aim I is to evaluate the role of RA as a repressor of HIV-1 replication in cytokine activated primary macrophages and to determine whether repression requires the induction of specific cellular signaling pathways. The goal of aim 2 is to evaluate the role of RA as an regulator of the HIV-1 chromatin structure in established cell lines and primary cells. RA-induced changes in nucleosome binding and the post-translational modification of histones will be examined using in vivo nucleosome mapping and footprinting as well as chromatin immunoprecipitation assays. These aims are part of the long term goal of delineating the molecular mechanisms of retinoid-mediated repression and determining their therapeutic potential.