Heat shock protein 90 and HIV persistence

描述：高效抗逆转录病毒疗法（HAART）成功地将病毒载量降低到检测极限以下，但在患者停止治疗后，HIV复制很快恢复。据信，一小部分持续性HIV感染的静止CD4+ T细胞在缺乏HAART的情况下被激活，并有助于患者病毒载量的反弹。这导致了一种新的治疗策略，提出了潜伏清除药物和HAART的组合，期望激活hiv感染的静息CD4+ T细胞将通过病毒介导的细胞死亡、免疫系统和HAART来消除持续的病毒库。静息CD4+ T细胞中HIV潜伏期的重新激活也可以通过非化学方式由热休克诱导。在正在进行的实验中，我们发现热休克蛋白90 （Hsp90）对HIV复制至关重要，热休克（39.5℃）显著增加HIV传染性，同时增加Hsp90蛋白的表达。其他人的类似研究表明，热休克对HIV潜伏期的再激活依赖于Hsp90的表达。HIV潜伏期在静止的CD4+ T细胞中通过抑制病毒特异性蛋白的水平得以维持。细胞激活导致这些宿主因子的产生，但这些蛋白质需要被激活才能诱导HIV再激活。活性P-TEFb复合物和NF-？B家族转录因子对HIV再激活至关重要，这些细胞蛋白被Hsp90伴侣机制激活。同样，控制HIV潜伏期的某些染色质重塑蛋白被Hsp90激活并导致HIV再激活。上面提到的例子是大量研究的一部分，这些研究表明热休克，特别是热休克蛋白90，会影响HIV的复制。鉴于这些观察结果，我们假设Hsp90在重新激活HIV潜伏期中具有功能作用。这一假设将在以下特定目的的实验中得到解决：(1)研究Hsp90如何在静止的CD4+ T细胞中重新激活HIV潜伏期；(2)鉴定重新激活HIV潜伏期的Hsp90相互作用蛋白。这些研究包括在未转化的原代人淋巴细胞中表达Hsp90，并分析在潜伏感染的静息CD4+ T细胞中诱导HIV再激活的特异性Hsp90相互作用蛋白。这一假设将在人源化NSG-BLT小鼠HIV潜伏期模型中得到验证。这项提议的目的是鉴定hsp90相互作用蛋白，重新激活HIV潜伏期，分析这些蛋白可能会发现消除潜伏HIV储存库的新靶点。

DESCRIPTION: Highly active antiretroviral therapy (HAART) successfully reduces the viral load to below the limit of detection, but HIV replication resumes soon after patients cease therapy. It is believed that a small subset of persistent HIV- infected resting CD4+ T cells are activated in the absence of HAART and contribute to the rebound in patient viral load. This has led to a new treatment strategy that proposes a combination of latency-purging drugs and HAART, with the expectation that activating HIV-infected resting CD4+ T cells will eliminate the persistent viral reservoir by virus-mediated cell death, by the immune system, and by HAART. Reactivation of HIV latency in resting CD4+ T cells can also be induced nonchemically by heat shock. In ongoing experiments, we have found that heat shock protein 90 (Hsp90) is essential for HIV replication and that heat shock (39.5oC) significantly increases HIV infectivity with a simultaneous increase in Hsp90 protein expression. Similar studies by others suggest that reactivation of HIV latency by heat shock is dependent on Hsp90 expression. HIV latency is maintained in resting CD4+ T cells by suppression of the level of virus- specific proteins. Cellular activation results in production of these host factors, but these proteins need to be activated in order to induce HIV reactivation. The active P-TEFb complex and the NF-?B family of transcription factors are essential for HIV reactivation, and these cellular proteins are activated by the Hsp90 chaperone machinery. Similarly, certain chromatin-remodeling proteins that control HIV latency are activated by Hsp90 and lead to HIV reactivation. The examples mentioned above are part of a larger body of work showing that heat shock, and specifically Hsp90, influence HIV replication. Given these observations, we hypothesize that Hsp90 has a functional role in reactivating HIV latency. This hypothesis will be addressed in the experiments of the following Specific Aims: (1) to study how Hsp90 reactivates HIV latency in resting CD4+ T cells, and (2) to identify Hsp90-interacting proteins that reactivate HIV latency. These studies include expressing Hsp90 in untransformed primary human lymphocytes and analyzing the specific Hsp90-interacting proteins that induce HIV reactivation in latently infected resting CD4+ T cells. This hypothesis will be validated in the humanized NSG-BLT mouse model of HIV latency. The objective of this proposal is to identify Hsp90-interacting proteins that reactivate HIV latency, and analysis of these proteins may reveal novel targets for elimination of the latent HIV reservoir.