CBF-1 role in regulating HIV reservoir in microglial cells

项目摘要：尽管静止记忆的CD4T细胞是公认的最长寿的蓄水池 潜伏的HIV前病毒，现在人们普遍认为髓系细胞，特别是中枢神经系统(CNS)的髓系细胞- --包括血管周围巨噬细胞和小胶质细胞--也可以促进病毒库的形成。 与HIV潜伏期相关的分子机制主要是通过分析HIV潜伏期来确定的 感染的CD4淋巴样细胞。然而，对HIV在髓系细胞中的潜伏期/持久性知之甚少。 值得注意的是，中枢神经系统中携带艾滋病毒的髓系细胞的存在被证明是造成这一现象的关键因素。 与中枢神经系统炎症和促进HIV患者的HIV相关神经认知障碍(HAND)有关。小胶质细胞 细胞是中枢神经系统中HIV的主要储存库，但关于我们对 维持这些细胞中艾滋病毒储存库的分子机制。我们的长期目标是识别和 描述调节小胶质细胞中HIV潜伏期的潜在分子机制。重要的是 CBF-1介导的转录抑制在HIV潜伏期间的作用在淋巴细胞中得到了很好的证实。这个 这项资助的目的是表征CBF-1在小胶质细胞中HIV潜伏期间的作用。基于我们的 已发表的和初步的发现，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/减慢 HIV LTR的结构。我们的理由是，由于HIV潜伏期主要是在转录水平上调节的， 明确调控小胶质细胞中艾滋病毒转录的精确机制(S)将提供新的治疗方法 瞄准中南地区艾滋病毒宿主的机会。在目标1中，我们将研究CBF-1诱导的表观遗传学的作用 限制艾滋病毒转录的变化及其最终对艾滋病毒建立和维持的影响 艾滋病毒潜伏期的不同阶段。在目标2中，我们将描述cbf-1在HIV ltr招募的辅阻遏子复合体的特征。 以及它们在促进小胶质细胞中HIV蓄积方面的功能意义。一旦得出结论，我们将能够 定义CBF-1介导的机制，以促进艾滋病毒潜伏期的建立和维持 小胶质细胞。这些研究还将以CBF-1和它的形式提供明确的治疗靶点 辅阻遏子复合体，以同时解除多个抑制性表观遗传修饰。 提出的研究具有创新性，因为它使用了人类原代小胶质细胞，以及一种新的体外模型 小胶质细胞中HIV潜伏期的系统，第一次允许研究与 HIV进入和退出小胶质细胞的潜伏期，否则这是一个不可能的任务，因为不足 脑部尸检标本的可用性。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，将有助于优化治疗方案的设计 以艾滋病毒的中枢神经系统宿主为目标，有助于治疗方法。

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.