CBF-1 role in regulating HIV reservoir in microglial cells

项目概述：虽然静息记忆CD 4 + T细胞是最好的公认的长寿水库， 潜伏的HIV前病毒，现在普遍认为骨髓细胞，特别是中枢神经系统（CNS）的骨髓细胞， - 包括血管周围的巨噬细胞和小胶质细胞-也可以有助于病毒库。 通过对HIV潜伏期的分析，初步确定了HIV潜伏期的分子机制， 感染的CD 4+淋巴细胞。然而，对骨髓细胞中的HIV潜伏/持续性知之甚少。 值得注意的是，CNS中携带HIV的髓样细胞的存在被证明是促成 中枢神经系统炎症和促进HIV相关的神经认知障碍（HAND）的HIV患者。小胶质 细胞是中枢神经系统中主要的HIV储存库，然而，关于我们对HIV的理解， 维持HIV病毒在这些细胞中的储存的分子机制。我们的长期目标是确定和 表征调节小胶质细胞中HIV潜伏期的潜在分子机制。重要 CBF-1介导的转录抑制在HIV潜伏期期间的作用在淋巴样细胞中已被充分确立。的 该基金的目的是描述CBF-1在小胶质细胞中HIV潜伏期中的作用。基于我们 已发表的和初步的研究结果，我们假设，类似于淋巴细胞，在小胶质细胞CBF- 1通过诱导转录抑制异染色质的产生促进HIV潜伏/减速 HIV LTR的结构。我们的理由是，由于艾滋病毒的潜伏期主要是在转录水平上调节， 确定在小胶质细胞中调节HIV转录的精确机制将提供新的治疗方法， 有机会靶向中枢神经系统中的HIV储库。在目标1中，我们将研究CBF-1诱导的表观遗传作用， 限制HIV转录的变化及其对建立和维持 HIV潜伏期的各个阶段。在目标2中，我们将描述CBF-1在HIV LTR招募的辅阻遏物复合物的特征 以及它们在促进小胶质细胞中HIV储库中的功能意义。一旦结束，我们将能够 确定CBF-1介导的促进HIV潜伏期建立和维持的机制， 小胶质细胞这些研究还将以CBF-1的形式提供明确的治疗靶点， 辅阻遏物复合物，以便同时解除多种阻遏性表观遗传修饰。 拟议的研究是创新的，因为它使用了人类原代小胶质细胞和一种新的离体模型 系统的艾滋病毒潜伏在小胶质细胞，第一次，允许研究的分子相关性， HIV进入和退出小胶质细胞中的潜伏期，这在其他情况下是不可能完成的任务， 大脑尸检标本的可用性。这一贡献意义重大，因为已确定的机制， 调节HIV在小胶质细胞中的转录和潜伏期，将有助于设计优化的治疗方法。 靶向中枢神经系统的艾滋病病毒库，有助于治愈方法。

Project Summary: Although the resting memory CD4+ T cells are the best-recognized long-lived reservoirs of latent HIV provirus, it is now well accepted that the myeloid cells, especially of the central nervous system (CNS)- -including perivascular macrophages and microglial cells--can also contribute to viral reservoirs. The molecular mechanisms relevant to HIV latency are primarily defined by analyzing HIV latency in latently infected CD4+ lymphoid cells. However, very little is known about HIV latency/persistence in myeloid cells. Notably, the presence of HIV-harboring myeloid cells in the CNS are documented to be the key factor contributing to CNS inflammation and promoting HIV-associated neurocognitive disorder (HAND) in HIV patients. Microglial cells are the main HIV reservoir in the CNS, yet a gap in the knowledge regarding our understanding of the molecular mechanisms that maintains HIV reservoirs in those cells. Our long term goal is identifying and characterizing the underlying molecular mechanisms that regulate HIV latency in microglial cells. The important role of CBF-1-mediated transcriptional inhibition during HIV latency is well established in lymphoid cells. The objective of this grant is to characterize the role of CBF-1 during HIV latency in microglial cells. Based on our published and preliminary findings, we have hypothesized that, similar to lymphocytes, in microglial cells CBF- 1 promotes HIV latency/slowdown by inducing the generation of transcriptionally-repressive heterochromatin structures at HIV LTR. Our rationale is that since HIV latency is primarily regulated at the transcriptional level, defining the precise mechanism(s) that regulate HIV transcription in microglial cells will offer new therapeutic opportunities to target HIV reservoirs in the CNS. In Aim 1, we will examine the role of CBF-1-induced epigenetic changes in restricting HIV transcription and their eventual impact on the establishment and the maintenance phases of HIV latency. In Aim 2, we will characterize the corepressor complexes that CBF-1 recruits at HIV LTR and their functional significance in promoting HIV reservoir in microglial cells. Upon conclusion, we will be able to define the CBF-1-mediated mechanisms that facilitate the establishment and maintenance of HIV latency in microglial cells. These studies will also provide a well-defined therapeutic target in the form of CBF-1 and its corepressor complexes in order to relieve multiple repressive epigenetic modifications simultaneously. Proposed research is innovative because it uses human primary microglial cells, and a novel ex vivo model system for HIV latency in microglial cells that, for the first time, allows the studies of the molecular correlates for HIV entry and exit into latency in microglial cells, which is otherwise an impossible task due to insufficient availability of brain autopsy specimens. This contribution is significant since the identified mechanisms, which regulate HIV transcription and latency in microglial cells, will facilitate the designing of optimized therapies targeting CNS reservoirs of HIV, contributing to cure approaches.