HIV Tat and morphine-mediated pyroptosis activates astrocytes: Role of NLRP6 inflammasome in HAND

项目摘要 尽管联合抗逆转录病毒疗法能够显著抑制病毒血症，但大脑继续 成为艾滋病毒低水平复制的蓄水池。使这一问题更加复杂的是药物滥用与 艾滋病毒相关的神经认知障碍和神经艾滋病毒。在几种滥用药物中，阿片类药物的使用是 在艾滋病毒感染者中非常普遍，既是一种滥用药物，也是止痛药物。一直以来 研究表明，艾滋病毒/艾滋病毒蛋白和滥用药物如吗啡都会导致神经炎症， 反过来，又涉及到炎性小体的激活。越来越多的证据也表明，非编码RNA 作为表观遗传和转录后调节因子，控制重要的细胞功能，包括激活， 从而改变了各种生物过程的动态。虽然HIV蛋白和阿片类药物都已被证明 为了改变中枢神经系统细胞的基因表达谱，人们对详细的分子水平缺乏了解 艾滋病病毒Tat蛋白和Tat蛋白协同作用的机制(S) 吗啡对星形胶质细胞激活的影响。这一提议的中心假设是HIV Tat和吗啡，通过 明确的调控机制(S)增强星形胶质细胞的激活，进而导致恶化 神经炎。SIV前额叶全基因组亚硫酸氢盐测序的初步数据 感染的恒河猴表现出NLRP6(NOD样受体家族，吡林)DNA低甲基化增加 含有结构域的蛋白6)启动子，伴随着NLRP6表达的上调。另外， 人类和小鼠原代星形胶质细胞暴露于HIV、TAT和吗啡也导致减少 MicroRNA-152的表达伴随着NLRP6的表达增加。有趣的是，我们还 发现这些原代星形胶质细胞暴露在HIV Tat或吗啡中会导致细胞数量增加 炎症性细胞因子(IL-1、β和IL-18)通过上睑下垂表达增加而激活。基于 中心假设和可靠的初步数据，这一建议导致了以下具体目标：具体目标 1：确定microRNA-152介导NLRP6炎症小体激活的分子机制(S) 人类免疫缺陷病毒TAT和吗啡暴露的星形胶质细胞；特定目标2：确定表观遗传学机制(S) 在体外参与HIVTAT和吗啡暴露的星形胶质细胞中NLRP6启动子DNA的低甲基化； 特异性目标3：验证HIV、Tat和吗啡对NLRP6介导的炎症小体的联合作用 星形胶质细胞激活，在体内。了解HIV诱导星形胶质细胞激活的机制 吗啡将为未来新疗法的发展奠定基础，旨在抑制艾滋病毒和 阿片类药物介导的神经炎性反应。

Project Summary Despite the ability of combination antiretroviral therapy to dramatically suppress viremia, the brain continues to be a reservoir of HIV low-level replication. Adding further complexity to this is the co-morbidity of drug abuse with HIV-associated neurocognitive disorders and neuroHIV. Among several abused drugs, the use of opiates is highly prevalent in HIV-infected individuals, both as an abused drug as well as for pain management. It has been shown that both HIV/HIV proteins and abused drugs such as morphine contribute to neuroinflammation, which, in turn, involves activation of the inflammasomes. Mounting evidence has also shown that noncoding RNAs function as epigenetic and post-transcriptional regulators controlling vital cellular functions, including activation, thus altering the dynamics of various biological processes. While both HIV proteins and opioids have been shown to change the gene expression profiles of CNS cells, there is a gap of knowledge on the detailed molecular mechanism(s) underlying the co-operative effects of HIV Transactivator of transcription (Tat) protein and morphine on astrocyte activation. The central hypothesis of this proposal is that HIV Tat and morphine, via distinct regulatory mechanism(s) augment astrocyte activation leading, in turn, to exacerbated neuroinflammation. Our preliminary data on whole-genome bisulfite sequencing in the frontal cortices of SIV- infected rhesus macaques show increased DNA hypomethylation of the NLRP6 (NOD-like receptor family, pyrin domain-containing protein 6) promoter with a concomitant upregulation in NLRP6 expression. Additionally, exposure of human and mouse primary astrocytes to HIV Tat and morphine also resulted in decreased expression of microRNA-152 that was accompanied by increased expression of NLRP6. Interestingly, we also found that exposure of these primary astrocytes to either HIV Tat or morphine resulted in increased cellular activation with increased expression of proinflammatory cytokines (IL1β and IL18) via pyroptosis. Based on the central hypothesis and the reliable preliminary data, this proposal led to the following specific aims: Specific Aim 1: Determine the molecular mechanism(s) involved in microRNA-152 mediated NLRP6 inflammasome activation in HIV Tat and morphine-exposed astrocytes in vitro; Specific Aim 2: Determine the epigenetic mechanism(s) involved in promoter DNA hypomethylation of the NLRP6 in HIV Tat and morphine-exposed astrocytes in vitro; Specific Aim 3: Validate the combinatorial effects of HIV Tat and morphine on NLRP6 inflammasome mediated astrocyte activation, in vivo. Understanding the mechanisms responsible for astrocyte activation induced by HIV and morphine will set the stage for the future development of novel therapeutics aimed at dampening HIV and opiate-mediated neuroinflammatory responses.