HIV Latency, Epigenetics, and Therapeutics

描述(由申请人提供)：逆转录病毒基因组与宿主染色质的整合使艾滋病毒能够在感染细胞内持续存在。终身治疗的困难使得必须了解艾滋病毒持续感染的机制，制定克服潜在艾滋病毒感染的策略。组蛋白修饰酶在前病毒潜伏期中起关键作用，组蛋白脱乙酰酶(HDAC)抑制剂诱导HIV启动子和病毒表达。滥用药物，尤其是可卡因，可以通过表观遗传修饰改变细胞功能。这种环境对记忆T细胞和持续HIV感染的持久表观遗传影响尚不清楚。需要更全面地了解表观遗传学如何调节艾滋病毒前病毒的平静，以及暴露于可卡因是否会改变潜伏感染。为了实现这一点，我们将使用潜伏期的转换和原代细胞模型以及从患者(包括有可卡因暴露史的患者)获得的潜伏感染细胞来综合评估以下假设。特定目的I：特定的HDAC被特异性地招募来作用于HIV启动子，并且靶向的HDAC抑制诱导静止的前病毒HIV的表达：辅因子复合体招募HDAC 1、2和3作用于HIV LTR，其中HDAC异构体的占据是自动调节的。阻断选定的HDAC的功能可以在模型系统中诱导潜伏的前病毒表达，并允许从HIV感染的ART治疗患者的静止CD4+T细胞中恢复病毒。特定目的II：组蛋白去乙酰化是在沉默的LTR上建立限制性染色质结构的早期步骤：组蛋白去乙酰化后的一系列染色质修饰，包括组蛋白甲基化，导致从可诱导状态到锁定状态的转变，降低HIV启动子对单一诱导信号的反应性。具体目标三：可卡因的使用将改变潜伏感染细胞的数量，降低它们对诱导信号的反应：通过诱导静止的CD4+T细胞的组蛋白乙酰化，暴露可卡因将减少对HDAC抑制剂反应的潜伏感染细胞的数量。详细研究HIV感染者的表观遗传学和前病毒静止的调控，包括滥用药物对潜伏的HIV感染的影响，将有助于我们对HIV持续感染的理解。这些研究将指导治疗方法的发展，以阻断持续的前病毒感染，并确保这种方法适用于广泛的患者群体。

DESCRIPTION (provided by applicant): The integration of retroviral genomes into host chromatin allows HIV to persist within infected cells. The difficulties of lifelong therapy make it imperative to understand the mechanisms of persistent HIV infection, to devise strategies to overcome latent HIV infection. Histone modifying enzymes play a critical role in proviral latency, and histone deacetylase (HDAC) inhibitors induce HIV promoter and viral expression. Drugs of abuse, most notably cocaine, can alter cellular function via epigenetic modification. The durable, epigenetic effect of such environmental influences on memory T cells and persistent HIV infection is unexplored. A more complete understanding of how epigenetics modulate HIV proviral quiescence, and whether latent infection is altered by exposure to cocaine is needed. To achieve this we will comprehensively evaluate the following hypotheses using transformed and primary cell models of latency, and latently infected cells obtained from patients, including patients with a history of cocaine exposure. Specific Aim I: Selected HDACs are specifically recruited to act at the HIV promoter, and targeted HDAC inhibition induces the expression of quiescent proviral HIV: Cofactor complexes recruit HDACs 1, 2, and 3 to act on the HIV LTR, where HDAC isoform occupancy is autoregulated. Blockade of the function of selected HDACs can induce latent proviral expression in model systems, and allow viral recovery from the resting CD4+ T cells of HIV-infected, ART-treated patients. Specific Aim II: Histone deacetylation is an early step in the establishment of restrictive chromatin structures on the silenced LTR: An extensive series of chromatin modifications following histone deacetylation, including histone methylation, results in transition from the "inducible" to the "locked" state, decreasing responsiveness of the HIV promoter to single inductive signals. Specific Aim III: Cocaine use will alter the population of latently infected cells, reducing their response to inductive signals: By inducing histone acetylation in resting CD4+ T cells, cocaine exposure will reduce the number of latently infected cells in the "inducible state" responsive to HDAC inhibitors. Detailed studies of the epigenetics and regulation of proviral quiescence in HIV-infected patients, including the effects of drugs of abuse on latent HIV infection, will enhance our understanding of persistent HIV infection. These studies will guide the development of therapeutic approaches to disrupt persistent proviral infection, and insure that such approaches are applicable to broad populations of patients.