Modulation of BRD4 to epigenetically suppress HIV

调节 BRD4 以表观遗传抑制 HIV

• 批准号: 10434159
• 负责人: Haitao Hu
• 金额: $ 60.17万
• 依托单位: UNIVERSITY OF TEXAS MED BR GALVESTON
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-06-17 至 2026-05-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10434159
• 关键词: Aftercare; Binding; Binding Sites; Bromodomain; CD4 Positive T Lymphocytes; Cell model; Cells; Chemicals; Chromatin; Chromatin Structure; Complex; Crystallization; Docking; Epigenetic Process; Future; Genetic Transcription; Genome; Goals; HIV; Histones; Human; In Vitro; Infection; Investigation; Knock-out; Laboratories; Lead; Lysine; Mediating; Microglia; Molecular; Molecular Probes; Mus; Myeloid Cells; Pathway interactions; Peripheral Blood Mononuclear Cell; Protein Family; Protein Isoforms; Proteins; Reader; Regulation; Repression; Research; Residual state; Role; Site; Structure; T-Lymphocyte; Tertiary Protein Structure; Testing; Toxic effect; Transactivation; Transcription Elongation; Withholding Treatment; analog; base; design; epigenetic regulation; humanized mouse; in vivo; inhibitor; innovation; latent infection; mouse model; multidisciplinary; novel; novel strategies; overexpression analysis; pandemic disease; prevent; protein protein interaction; recruit; scaffold; small molecule; transcriptome sequencing; transcriptomics; viral DNA

ABSTRACT Integration of HIV viral DNA into host cell genomes and establishment of stable latent infection have posed a major obstacle for finding an HIV cure. HIV proviral expression in cell reservoirs is regulated by host epigenetic and transcriptional mechanisms. Identification of effective approaches targeting host machineries to disrupt or enforce HIV latency is a significant goal. BRD4 is an epigenetic reader that belongs to the bromodomain (BD) and extra-terminal domain (ET) protein family (BET). Via the BDs, BRD4 binds to acetyl-lysine (KAc) residues in chromatin histones and serves as a scaffolding platform for recruiting partner proteins through protein-protein interactions (PPI) to regulate gene transcription, including HIV. Modulation of BET/BRD4 by a pan-BET inhibitor (JQ1), which targets the classic KAc binding site in BDs, has been shown to activate HIV transcription. Recent studies by my group and others indicate that BRD4 is functionally versatile, and its activity on gene transcription is tailored by specific partner proteins it engages. Using structure-aided design, our studies (1, 2) have identified a lead small molecule (ZL0580) and several analogs that are distinct from JQ1 but induce HIV transcriptional suppression through BRD4. We demonstrate that ZL0580 induces suppression of both transcriptionally active and latent HIV in multiple cell models, including J-Lat, CD4 T cells and myeloid cells/microglia. Docking analyses of binding modes and mechanistic investigations indicate that unlike JQ1, ZL0580 targets a distinct new region of BRD4 BD1 for binding [non-acetyl-lysine (KAc) site] and induces HIV transcriptional suppression by inhibiting Tat transactivation and by inducing a repressive chromatin structure at the HIV LTR. Based on these novel findings, our central hypothesis is that host BRD4 and its associated epigenetic machinery can be modulated to repress HIV, leading to enforced HIV latency. Other than ZL0580, our ongoing research has identified another analog (YL0255) that is structurally close to ZL0580 and induces stronger HIV suppression. In this application, we will use ZL0580 and YL0255 as two novel molecular probes to systemically investigate modulation of BRD4 in HIV epigenetic suppression. In Aim 1, we will determine if BRD4 is a selective protein target for ZL0580/YL0255 and the underlying structural basis. In Aim 2, we will elucidate the molecular mechanisms by which modulation of BRD4 by ZL0580/YL0255 induces HIV epigenetic suppression. In Aim 3, as a proof of concept, we will examine if modulation of BRD4 by ZL0580/YL0255 induces repression of latent HIV in vivo. Collectively, these studies are critical for better understanding HIV epigenetic regulation and latency and will lay critical groundwork for developing novel strategies for inducing HIV suppression and/or silencing in future.

抽象的 HIV病毒DNA整合到宿主细胞基因组中并建立稳定的潜伏感染已成为 寻找艾滋病毒治疗方法的主要障碍。 HIV原病毒在细胞库中的表达受到宿主表观遗传的调节 和转录机制。确定针对主机机器进行破坏或破坏的有效方法 加强艾滋病毒潜伏期是一个重要目标。 BRD4 是属于溴结构域 (BD) 的表观遗传读取器 和末端域外 (ET) 蛋白家族 (BET)。通过 BD，BRD4 与乙酰基赖氨酸 (KAc) 残基结合 位于染色质组蛋白中，并作为通过蛋白质-蛋白质招募伴侣蛋白的支架平台 相互作用（PPI）来调节基因转录，包括 HIV。泛 BET 抑制剂对 BET/BRD4 的调节 (JQ1) 靶向 BD 中的经典 KAc 结合位点，已被证明可以激活 HIV 转录。最近的 我的团队和其他人的研究表明 BRD4 具有多种功能，并且它对基因转录的活性 是由它所参与的特定伙伴蛋白定制的。使用结构辅助设计，我们的研究 (1, 2) 已经确定 一种先导小分子 (ZL0580) 和几种与 JQ1 不同但诱导 HIV 转录的类似物 通过 BRD4 抑制。我们证明 ZL0580 诱导抑制转录活性 以及多种细胞模型中的潜伏 HIV，包括 J-Lat、CD4 T 细胞和骨髓细胞/小胶质细胞。对接分析 结合模式和机制研究表明，与 JQ1 不同，ZL0580 靶向一个独特的新区域 BRD4 BD1 结合[非乙酰基赖氨酸 (KAc) 位点]并通过抑制 Tat 反式激活并通过在 HIV LTR 处诱导抑制性染色质结构。根据这些小说 研究结果表明，我们的中心假设是宿主 BRD4 及其相关的表观遗传机制可以被调节 抑制艾滋病毒，导致艾滋病毒潜伏期延长。除了 ZL0580 之外，我们正在进行的研究还发现了另一种 类似物 (YL0255)，其结构与 ZL0580 接近，可诱导更强的 HIV 抑制作用。在这个应用程序中， 我们将使用ZL0580和YL0255作为两种新型分子探针来系统地研究BRD4的调节 HIV表观遗传抑制。在目标 1 中，我们将确定 BRD4 是否是 ZL0580/YL0255及底层结构基础。在目标 2 中，我们将通过以下方式阐明分子机制： ZL0580/YL0255 对 BRD4 的调节可诱导 HIV 表观遗传抑制。在目标 3 中，作为证明 概念，我们将检查 ZL0580/YL0255 对 BRD4 的调节是否会诱导体内潜伏 HIV 的抑制。 总的来说，这些研究对于更好地了解艾滋病毒表观遗传调控和潜伏期至关重要，并将奠定 为未来制定抑制和/或沉默艾滋病毒的新策略奠定了重要基础。