Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas, USA.
Institute for Human Infections and Immunity, Sealy Institute for Vaccine Sciences, University of Texas Medical Branch, Galveston, Texas, USA.
J Virol. 2020 May 18;94(11). doi: 10.1128/JVI.01880-19.
Brain-resident microglia and myeloid cells (perivascular macrophages) are important HIV reservoirs , especially in the central nervous system (CNS). Despite antiretroviral therapy (ART), low-level persistent HIV replication in these reservoirs remains detectable, which contributes to neuroinflammation and neurological disorders in HIV-infected patients. New approaches complementary to ART to repress residual HIV replication in CNS reservoirs are needed. Our group has recently identified a BRD4-selective small molecule modulator (ZL0580) that induces the epigenetic suppression of HIV. Here, we examined the effects of this compound on HIV in human myeloid cells. We found that ZL0580 induces potent and durable suppression of both induced and basal HIV transcription in microglial cells (HC69) and monocytic cell lines (U1 and OM10.1). Pretreatment of microglia with ZL0580 renders them more refractory to latent HIV reactivation, indicating an epigenetic reprogramming effect of ZL0580 on HIV long terminal repeat (LTR) in microglia. We also demonstrate that ZL0580 induces repressive effect on HIV in human primary monocyte-derived macrophages (MDMs) by promoting HIV suppression during ART treatment. Mechanistically, ZL0580 inhibits Tat transactivation in microglia by disrupting binding of Tat to CDK9, a process key to HIV transcription elongation. High-resolution micrococcal nuclease mapping showed that ZL0580 induces a repressive chromatin structure at the HIV LTR. Taken together, our data suggest that ZL0580 represents a potential approach that could be used in combination with ART to suppress residual HIV replication and/or latent HIV reactivation in CNS reservoirs, thereby reducing HIV-associated neuroinflammation. Brain-resident microglia and perivascular macrophages are important HIV reservoirs in the CNS. Persistent viral replication and latent HIV reactivation in the CNS, even under ART, are believed to occur, causing neuroinflammation and neurological disorders in HIV-infected patients. It is critical to identify new approaches that can control residual HIV replication and/or latent HIV reactivation in these reservoirs. We here report that the BRD4-selective small molecule modulator, ZL0580, induces potent and durable suppression of HIV in human microglial and monocytic cell lines. Using an HIV-infected, ART-treated MDM model, we show that ZL0580 also induces suppressive effect on HIV in human primary macrophages. The significance of our research is that it suggests a potential new approach that has utility in combination with ART to suppress residual HIV replication and/or HIV reactivation in CNS reservoirs, thereby reducing neuroinflammation and neurological disorders in HIV-infected individuals.
脑驻留小胶质细胞和髓样细胞（血管周巨噬细胞）是 HIV 的重要储存库，尤其是在中枢神经系统（CNS）中。尽管有抗逆转录病毒治疗（ART），但这些储存库中仍可检测到低水平持续的 HIV 复制，这导致 HIV 感染患者的神经炎症和神经紊乱。需要寻找新的方法来补充 ART，以抑制 CNS 储存库中残留的 HIV 复制。我们的研究小组最近发现了一种 BRD4 选择性小分子调节剂（ZL0580），它可以诱导 HIV 的表观遗传抑制。在这里，我们研究了该化合物对人髓样细胞中 HIV 的影响。我们发现，ZL0580 可诱导小胶质细胞（HC69）和单核细胞系（U1 和 OM10.1）中诱导和基础 HIV 转录的有效且持久的抑制。ZL0580 预处理小胶质细胞可使其对潜伏 HIV 再激活更具抗性，表明 ZL0580 对小胶质细胞 HIV 长末端重复（LTR）的表观遗传重编程作用。我们还证明，ZL0580 通过在 ART 治疗期间促进 HIV 抑制，对人原代单核细胞衍生的巨噬细胞（MDM）中的 HIV 产生抑制作用。在机制上，ZL0580 通过破坏 Tat 与 CDK9 的结合来抑制 Tat 的反式激活，这是 HIV 转录延伸的关键过程。高分辨率微球菌核酸酶作图显示，ZL0580 诱导 HIV LTR 处的抑制性染色质结构。总之，我们的数据表明，ZL0580 代表了一种潜在的方法，可与 ART 联合使用，以抑制 CNS 储存库中残留的 HIV 复制和/或潜伏 HIV 再激活，从而减少 HIV 相关的神经炎症。脑驻留小胶质细胞和血管周巨噬细胞是中枢神经系统中 HIV 的重要储存库。据信，即使在接受 ART 治疗的情况下，CNS 中的病毒持续复制和潜伏的 HIV 再激活也会发生，从而导致 HIV 感染患者的神经炎症和神经紊乱。因此，确定新的方法来控制这些储存库中残留的 HIV 复制和/或潜伏的 HIV 再激活至关重要。我们在这里报告，BRD4 选择性小分子调节剂 ZL0580 可有效且持久地抑制人小胶质细胞和单核细胞系中的 HIV。使用感染 HIV 并接受 ART 治疗的 MDM 模型，我们表明 ZL0580 还可诱导人原代巨噬细胞中 HIV 的抑制作用。我们研究的意义在于，它提出了一种潜在的新方法，与 ART 联合使用，可抑制 CNS 储存库中残留的 HIV 复制和/或 HIV 再激活，从而减少 HIV 感染者的神经炎症和神经紊乱。
