HTS for Synergistic Activators of Latent HIV-1 Infection

描述（由申请人提供）：艾滋病毒-1潜伏期使病毒在抗逆转录病毒治疗下仍能持续存在，这可能是开发艾滋病毒-1感染的治愈性治疗方法需要克服的主要障碍。虽然很明显需要根除潜伏的HIV-1储存库，但尚不清楚如何实现这一目标。在分子生物学水平上，目前的HIV-1研究主要集中在潜伏HIV-1感染的分子控制一定不同于诱导细胞基因的控制，其特征在于病毒LTR处存在限制性染色质环境，但当潜伏病毒整合到主动表达的宿主基因中时，这种限制性染色质环境是如何形成的尚不清楚。当一个复杂的限制性染色质结构被认为保护LTR时，如何在潜伏病毒LTR中发现暂停的RNAP II ？这种对限制性染色质环境作为潜伏性HIV-1感染的分子控制机制的关注转化为药物发现和临床应用，其中HDAC抑制剂被视为HIV-1再激活策略的圣杯。然而，在仔细查阅文献后发现，HDAC抑制剂作为HIV-1再激活剂在临床上被追求，无论是在许多潜伏感染模型中，还是在离体实验或临床研究中，都没有显示出令人信服的疗效。可能的例外是SAHA，临床批准作为HDAC抑制剂伏立诺他。在大多数实验系统中，包括我们的系统，SAHA表现出一定的HIV-1再激活能力，但SAHA最初是作为一种高效的细胞分化剂开发的，使用HMBA(另一种细胞分化剂，可重新激活潜伏的HIV-1作为结构模板。为此，我们在此报告，先前对HIV-1再激活药物组合的药物筛选显示，fda批准的一组具有细胞分化能力的药物或化合物，包括放射霉素、阿克拉霉素、阿糖胞苷和阿帕迪克林，通过低水平激活，使潜伏感染再激活。我们假设细胞分化药物可以通过协同激活剂激活潜伏的HIV-1感染，而协同激活剂本身仅发挥最小的激活作用。因此，该申请的两个目标是：(i)确定与启动药物联合触发系统范围再激活的协同激活因子；（ii）描述差异化药物如何改变细胞转录因子谱和信号转导途径，从而引发潜伏的HIV-1感染再激活。该应用程序的目标是确定针对潜伏HIV-1感染的多个分子控制水平的多药物组合，以触发再激活。这将通过药物筛选或合理选择化合物/药物来实现，随着我们越来越详细地了解已鉴定的药物如何改变对潜伏HIV-1感染事件的细胞控制，这将成为可能。

DESCRIPTION (provided by applicant): HIV-1 latency, which allows the virus to persist in the presence of antiretroviral therapy, is likely the major hurdle to overcome towards the development of a curative therapy for HIV-1 infection. While it is clear that the latent HIV-1 reservoir needs to be eradicated, it is unclear how this can be achieved. At the molecular biology level, current HIV-1 research focuses on the idea that molecular control of latent HIV-1 infection must be different from the control of inducible cellular genes and is characterized by the presence of a restrictive chromatin environment at the viral LTR. But how such a restrictive chromatin environment can form when the latent virus is integrated into actively expressed host-genes is unclear. How can paused RNAP II be found at the latent viral LTR, when a complex restrictive chromatin structure supposedly shields the LTR? This focus on a restrictive chromatin environment as the molecular control mechanism for latent HIV-1 infection translates into drug discovery and clinical application, where HDAC inhibitors are viewed as the holy grail of HIV-1 reactivation strategies. However, upon closer review of the literature, HDAC inhibitors, which are clinically pursued as HIV-1 reactivating agents, do not show convincing efficacy, neither in many models of latent infection, nor in ex vivo experiments or clinical studies. The possible exception is SAHA, clinically approved as the HDAC inhibitor vorinostat. SAHA exhibits some HIV-1 reactivating capacity in most experimental systems, including ours, but SAHA was initially developed as a highly potent cell-differentiating agent, using HMBA, another cell differentiating agent that reactivates latent HIV-1 as a structural template. To this end, we here report that a previous drug screen for HIV-1 reactivating drug combinations revealed that a panel of FDA-approved drugs or compounds with reported cell-differentiating capacity including dactinomycin, aclacinomycin, cytarabine and aphidicolin prime latent infection for reactivation by low-level activation. We hypothesize that cell-differentiating drugs can act to prime latent HIV-1 infection for reactivation by synergistic activators, which by themselves only exert a minimal activating effect. Thus the two objectives of the application are (i) to identify synergistic activators that trigger system-wide reactivation in combination with the priming drugs and (ii) to describe how differentiating drugs alter the cellular transcription factor profiles and signal transduction pathways to prime latent HIV-1 infection for reactivation. The goal of the application is to identiy multi-drug combinations that target latent HIV-1 infection at several levels of molecular control t trigger reactivation. This will be achieved through drug screening or by rational selection of compounds/drugs that will be enabled as we gain increasingly detailed insights into how the identified drugs alter the cellular control over the latent HIV-1 infection events.