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到的限度以下，但在患者停止治疗后不久，艾滋病毒复制就恢复了。据信，在没有HAART的情况下，一小部分持续感染HIV的静息CD4+T细胞被激活，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，提出了潜伏期清除药物和HAART的组合，期望激活HIV感染的静止CD4+T细胞将通过病毒介导的细胞死亡、免疫系统和HAART消除持久的病毒库。热休克也可以非化学方式诱导静息的CD4+T细胞中HIV潜伏期的重新激活。在正在进行的实验中，我们发现热休克蛋白90(Hsp90)对HIV复制是必不可少的，并且热休克(39.5oC)显著增加HIV的传染性，同时Hsp90蛋白表达增加。其他人的类似研究表明，热休克重新激活HIV潜伏期取决于Hsp90的表达。HIV潜伏期是通过抑制病毒特异性蛋白水平在静息的CD4+T细胞中维持的。细胞激活会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重新激活。活跃的P-TEFb复合体和核因子-？B转录因子家族是HIV重新激活所必需的，这些细胞蛋白由Hsp90分子伴侣机制激活。同样，某些控制HIV潜伏期的染色质重塑蛋白被Hsp90激活，并导致HIV重新激活。上面提到的例子是一个更大的工作的一部分，表明热休克，特别是Hsp90，影响艾滋病毒复制。鉴于这些观察，我们假设Hsp90在重新激活HIV潜伏期方面具有功能作用。这一假设将在以下特定目标的实验中得到解决：(1)研究Hsp90如何重新激活静止的CD4+T细胞中的HIV潜伏期，以及(2)鉴定Hsp90与重新激活HIV潜伏期的相互作用蛋白。这些研究包括在未转化的原代人类淋巴细胞中表达Hsp90，并分析在潜伏感染的静止CD4+T细胞中诱导HIV重新激活的特定Hsp90相互作用蛋白。这一假设将在人源化的HIV潜伏期NSG-BLT小鼠模型中得到验证。这项建议的目的是确定重新激活HIV潜伏期的Hsp90相互作用蛋白，对这些蛋白的分析可能揭示消除潜伏性HIV储备库的新靶点。

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.