Manipulating Epigenetic Control Mechanisms to Control HIV Transcription

描述（由申请人提供）：终身高效抗逆转录病毒疗法（HAART）不仅在患者管理、费用和长期毒性方面存在严重问题，而且不能从感染者身上根除病毒。HIV在HAART治疗中持续存在，这是由于在药物难以接近的部位进行低水平复制，以及在多种类型的潜伏感染中发展，包括长寿命记忆CD4+ T细胞群、巨噬细胞和大脑中的小胶质细胞。人们已经广泛认识到需要开发新的治疗工具来攻击潜伏感染人群，但使用传统的药物开发方法几乎没有进展。在这里，我们建议开发新的技术，允许利用自然的表观遗传沉默机制，DNA甲基化，来阻止HIV转录。作为开发治疗性沉默剂的前奏，需要更好地了解细胞用于控制逆转录病毒和反转录转座子的自然沉默机制。关于HIV沉默仍有待回答的关键问题包括：诱导沉默的主要序列触发器和机制是什么（即蛋白质抑制因子和/或病毒衍生的siRNA）？什么情况会导致病毒前DNA甲基化？是否类似的沉默机制在每一种被HIV感染的细胞类型中都起作用？滥用药物是否通过诱导组蛋白乙酰化来阻断HIV沉默？利用沉默的治疗方法包括开发增强DNA甲基化的小分子，通过短双链RNA（或其类似物）诱导基因特异性沉默，以及通过蛋白质介质将DNA甲基转移酶定向到启动子进行沉默。与需要持续给药的传统抗病毒药物相比，治疗性表观遗传基因沉默有可能在单次感染暴露后对病毒复制产生稳定的可遗传阻断

DESCRIPTION (provided by applicant): Lifelong highly active antiretroviral therapy (HAART) not only presents formidable problems in terms of patient management, cost and long-term toxicities but also fails to eradicate the virus from infected individuals. HIV persists in the face of HAART due to constitutive low-level replication in sites that are poorly accessible to drugs and the development of latent infections in a variety of types including the long-lived memory CD4+ T cell population, macrophages, and microglial cells in the brain. The need to develop novel therapeutic tools to attack the latently infected population has been widely recognized, but there has been little progress using conventional drug development approaches. Here we propose to develop novel technologies allowing exploitation a natural epigenetic silencing mechanism, DNA methylation, to block HIV transcription. As a prelude to developing therapeutic silencing agents, a much better understanding of the natural silencing mechanisms used by cells to control retroviruses and retrotranspons is needed. Key questions about HIV silencing that remain to be answered include: What are the primary sequence triggers and mechanisms that induce silencing (i.e. protein repressors and/or viral-derived siRNA)? What conditions lead to proviral DNA methylation? Do similar silencing mechanisms operate in each of the cell types infected by HIV? Do drugs of abuse block HIV silencing by inducing histone acetylation? Therapeutic approaches to exploit silencing include development of small molecules that enhance DNA methylation, gene-specific induction of silencing by short double-stranded RNA (or it analogues) and silencing by direction of DNA methyltransferases to promoters through protein mediators. In contrast to traditional antivirals, which require continuous administration, therapeutic epigenetic gene silencing has the potential to produce stable inheritable blocks to viral replication after only a single exposure of an infec