Exploration of novel block-and-lock agents alone and in combination for HIV remission in humanized mice

摘要 HIV-1转录抑制物在功能治疗方法中具有巨大的潜力，并可能改变 我们治疗艾滋病毒感染的方式。与目前的抗逆转录病毒疗法(ART)不同，转录抑制物可提供 减少由含有整合前病毒的长寿命细胞库产生的残留病毒血症的前景， 可能会减少正在进行的慢性免疫激活、炎症和艾滋病毒相关的共病 艾滋病病毒携带者的艺术追随者所经历的。此外，我们认为转录抑制物是 服从封锁和锁定的功能性治疗方法，目的是在没有艾滋病毒的情况下持久抑制艾滋病毒 通过对整合的前病毒进行永久的表观遗传沉默，进行日常治疗。这一假说是成立的 有效的TAT抑制剂二氢皮质酮A(DCA)的活性。HIV的体外和体内模型研究 随着时间的推移，DCA抑制HIV转录的潜伏期促使病毒启动子进入深度转录 抑制，在治疗中断或使用潜伏期复活剂(LRA)时限制病毒复活。 尽管它们具有巨大的潜力，但临床上仍然没有艾滋病毒转录抑制物，而且面临着 大规模生产DCA的成本正在减缓其临床研究的进展。 在这里，我们建议研究FDA批准的醛固酮拮抗剂螺内酯(SP)的再利用 用来抑制艾滋病毒的转录。SP的一种非靶标活性是通用的XPB亚基的降解 转录因子TFIIH，在基因转录起始点(TSS)的RNAPII启动过程中起关键作用。我们 体外实验证明，SP处理或shRNA敲除XPB选择性地抑制HIV转录和 阻止病毒从潜伏期重新激活，而不存在全球转录缺陷。这项研究强调了宿主因素 XPB是一种新的药物靶点，SP是一种潜在的阻断和锁定剂。在这里，我们建议探索一下 SP单独或与DCA联合作为人源化骨髓、胸腺肝中的阻断和锁定剂 (BLT)小鼠HIV感染模型的建立：1)确定SP治疗时间与残留时间的关系 HIV感染ART患者组织中病毒血症水平与慢性免疫激活/炎症的相关性 受抑制的BLT小鼠。；2)评估SP作为单一药物在缺乏 ART和研究病毒耐药性的演变；3)DCA和SP联合作为一线治疗对 已建立的病毒库的大小和病毒反弹的时间。我们预测，更长的艾滋病毒治疗时间 感染SP的BLT小鼠将与低级别HIV持续转录从 病毒库和可能的慢性免疫激活。重要的是，我们试图证明，一旦深入 转录抑制被确立，SP单独阻止病毒反弹。此外，当作为前线使用时， 治疗我们预计已建立的病毒库的大小将减少，与DCA的结合将 改善结果。这项研究将为转录抑制物的使用提供重要的概念验证 治疗艾滋病毒携带者并探索在未来的临床试验中测试的最佳实验环境

Abstract HIV-1 transcriptional inhibitors have immense potential in functional cure approaches and could transform the way we treat HIV infections. Unlike current antiretroviral therapy (ART), transcriptional inhibitors offer the prospect of reducing residual viremia derived from reservoir of long-lived cells containing integrated proviruses, likely reducing ongoing the chronic immune activation, inflammation and HIV-associated co-morbidities still experienced by ART-adherent individuals living with HIV. Furthermore, we believe transcriptional inhibitors are amenable to block-and-lock functional cure approaches, aimed at the durable suppression of HIV in the absence of daily therapy, through permanent epigenetic silencing of integrated proviruses. This hypothesis was founded on the activity of the potent Tat inhibitor didehydro-Cortistatin A (dCA). In in vitro and in vivo models of HIV latency, dCA inhibition of HIV transcription over time prompts the viral promoter into deep transcriptional inhibition, limiting viral reactivation upon treatment interruption or with latency reactivating agents (LRAs). Despite their great potential, there are still no HIV transcriptional inhibitors in the clinic, and challenges with the cost of large-scale production of dCA are slowing its progression towards clinical studies. Here we propose to investigate the repurposing the FDA approved aldosterone antagonist Spironolactone (SP) for HIV transcriptional inhibition. An off-target activity of SP is the degradation of the XPB subunit of the general transcription factor TFIIH, a key player in RNAPII initiation at the transcriptional start site (TSS) of genes. We demonstrated in vitro that SP treatment or shRNA knockdown of XPB selectively inhibits HIV transcription and blocks viral reactivation from latency without global transcriptomic defects. This study highlighted the host factor XPB as a novel drug target and SP as a potential block-and-lock agent. Here we propose to explore the potential of SP, alone or in combination with dCA, as a block-and-lock agent in the humanized bone-marrow, thymus liver (BLT) mouse model of HIV infection by: 1) Determine the relationship between SP treatment length with residual viremia levels in tissues and correlates of chronic immune activation/inflammation in HIV infected ART- suppressed BLT mice.; 2) Assess the ability of SP to maintain deep latency as a single drug in the absence of ART and study viral resistance evolution; 3) Impact of dCA and SP in combination as front-line therapy on the size of the established viral reservoir and time to viral rebound. We predict that longer treatment lengths of HIV infected BLT mice with SP will correlate with improved reduction of low-grade HIV persistent transcription from the viral reservoir and likely chronic immune activation. Importantly, we seek to demonstrate that once deep transcriptional suppression is established, SP alone blocks viral rebound. In addition, when used as front-line therapy we expect a reduction in the size of the established viral reservoir and the combination with dCA will improve the outcome. This study will provide an important proof-of-concept for the use of transcriptional inhibitors to treat people living with HIV and explore optimal experimental settings to be tested in future clinical trials