BET bromodomain-targeting compounds reactivate HIV from latency via a Tat-independent mechanism
BET bromodomain-targeting compounds reactivate HIV from latency via a Tat-independent mechanism
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DOI：
10.4161/cc.23309
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发表时间：
2013-02-01
期刊：
影响因子：
4.3
通讯作者：
Ott, Melanie
中科院分区：
文献类型：
--
作者：
Boehm, Daniela;Calvanese, Vincenzo;Ott, Melanie
最近在血液系统恶性肿瘤和慢性炎症中出现了药物抑制溴结构域和端外蛋白(BET)的治疗潜力。我们发现，BET抑制剂化合物(JQ1，i-Bet，i-BET151和MS417)从潜伏期开始重新激活HIV。这在含有潜伏的传染性艾滋病毒的多克隆Jurkat细胞群体以及艾滋病毒潜伏的初级T细胞模型中是明显的。重要的是，我们证明了这种激活依赖于正转录延伸因子p-TEFb，但独立于病毒TAT蛋白，论证了去除BET蛋白BRD4是BET抑制剂作用的主要机制的可能性，BRD4是TAT的细胞竞争对手。相反，我们发现相关的BET蛋白BRD2在没有TAT的情况下强制执行HIV潜伏期，这为BET抑制剂治疗HIV感染指出了一个新的靶点。在shRNA介导的基因敲除实验中，BRD2的敲除对HIV转录的激活程度与JQ1处理相同，而BRD4的影响较小。在单细胞时间推移荧光显微镜中，对大约2,000个病毒整合位点的定量分析证实了JQ1的非TAT依赖效应，并指出JQ1对转录延长有积极作用，同时推迟了病毒启动子上聚合酶复合体的重新启动。总体而言，我们的结果确定BRD2是一种新的TAT依赖的HIV转录抑制因子，并强调了BET抑制剂在逆转HIV潜伏时间方面的治疗潜力。
The therapeutic potential of pharmacologic inhibition of bromodomain and extraterminal (BET) proteins has recently emerged in hematological malignancies and chronic inflammation. We find that BET inhibitor compounds (JQ1, I-Bet, I-Bet151 and MS417) reactivate HIV from latency. This is evident in polyclonal Jurkat cell populations containing latent infectious HIV, as well as in a primary T-cell model of HIV latency. Importantly, we show that this activation is dependent on the positive transcription elongation factor p-TEFb but independent from the viral Tat protein, arguing against the possibility that removal of the BET protein BRD4, which functions as a cellular competitor for Tat, serves as a primary mechanism for BET inhibitor action. Instead, we find that the related BET protein, BRD2, enforces HIV latency in the absence of Tat, pointing to a new target for BET inhibitor treatment in HIV infection. In shRNA-mediated knockdown experiments, knockdown of BRD2 activates HIV transcription to the same extent as JQ1 treatment, while a lesser effect is observed with BRD4. In single-cell time-lapse fluorescence microscopy, quantitative analyses across similar to 2,000 viral integration sites confirm the Tat-independent effect of JQ1 and point to positive effects of JQ1 on transcription elongation, while delaying re-initiation of the polymerase complex at the viral promoter. Collectively, our results identify BRD2 as a new Tat-independent suppressor of HIV transcription in latently infected cells and underscore the therapeutic potential of BET inhibitors in the reversal of HIV latency.