Drugs of abuse and the epigenetic and signaling pathways controlling HIV latency

描述(由申请人提供)：三分之一的艾滋病毒感染者会患上某种形式的艾滋病毒相关神经认知障碍(HAND)。服用甲基苯丙胺等滥用药物会加重手部症状，但这些药物影响中枢神经系统(CNS)艾滋病毒疾病进展的细胞和分子机制仍不明确。在这项研究中，将检验这一假设，即HAND是由于潜伏感染的小胶质细胞间歇性重新激活导致神经毒性病毒蛋白Tat和gp120的表达。具体地说，我们将确定参与控制HIV潜伏期和获得抗炎M2表型的特定神经胶质细胞分子网络的特定贡献。我们最近对维持CHME-5/HIV细胞中HIV潜伏所需因子的无偏倚人shRNA文库筛选表明，配体激活的核受体(LA-NR)PPAR、RAR和RXR可以诱导微胶质细胞中的HIV沉默。PPAR、RAR和RXR激动剂和拮抗剂的化学筛选证实，这些受体在控制小胶质细胞中的HIV潜伏期方面具有关键的调节作用，并且受体激动剂是HIV重新激活的有效阻滞剂。在这项研究中，我们将研究LA-NR控制小胶质细胞中HIV转录的分子基础，以及这一调控途径是如何被冰毒修饰的。利用潜伏感染的小胶质细胞和神经元之间的新型共培养系统，我们将研究该方法对潜伏的HIV前病毒的诱导及其随后的神经毒性的影响。我们还将使用这个系统来评估PPAR、RAR和RXR激动剂的神经保护效果，这与最近的证据一致，即RXR激动剂贝沙罗汀或PPAR激动剂吡格列酮对阿尔茨海默病小鼠模型具有神经保护作用。最后，我们将使用一种新的双转基因小鼠模型JR-CSF/Hu-CycT1小鼠来评估配体核受体途径在HIV诱导的神经退化中的作用，该模型允许HIV在小鼠细胞中复制，并允许研究HIV感染如何导致脑功能障碍。我们还计划开发一种新的艾滋病毒诱导的神经变性模型，使用潜伏感染的小鼠单核细胞来重新填充CD11b-HSVtk转基因小鼠的大脑，在那里小胶质细胞已经耗尽。本申请中描述的多学科实验代表了对脑内小胶质细胞中HIV潜伏期的分子基础、冰毒对HIV潜伏期和神经变性的影响的全面评估，以及对核受体激动剂作为神经保护剂的潜力的广泛评估。我们相信，我们在这里提出的系统研究将为改善我们滥用药物患者的艾滋病毒相关性痴呆(HAD)和轻微认知运动障碍(MCMD)的临床管理奠定基础。

DESCRIPTION (provided by applicant): One in three HIV-infected individuals develops some form of HIV-associated neurocognitive disorder (HAND). Consumption of drugs of abuse such as methamphetamine (METH) aggravates the symptoms of HAND, but the cellular and molecular mechanisms by which these drugs impact HIV disease progression in the central nervous system (CNS) remain ill-defined. In this study will test the hypothesis that HAND arises from the intermittent reactivation of latently infected microglial cells leading to the expression f the neurotoxic viral proteins, Tat and gp120. Specifically, we will identify the specific contributon of specific molecular networks of glial cells that are involved in the control of HIV latency and te acquisition of an anti-inflammatory M2 phenotype. Our recent unbiased human shRNA library screen for factors that are required to maintain HIV latency in CHME-5/HIV cells showed that HIV silencing in microglila cells can be induced by the ligand- activated nuclear receptors (LA-NR) PPAR, RAR and RXR. Chemical screens of PPAR, RAR and RXR agonists and antagonists confirmed that these receptors have a critical regulatory role in controlling HIV latency in microglial cells and that receptor agonists are potent blockers of HIV reactivation. In this study we will study the molecular basis for LA-NR control of HIV transcription in microglial cells and how this regulatory pathway is modified by METH. Using novel co-culture systems between latently infected microglial cells and neurons we will study the impact METH on the induction of latent HIV proviruses and their subsequent neurotoxicity. We will also use this system to evaluate the neuroprotective effects of PPAR, RAR and RXR agonists, consistent with the recent demonstration that the RXR agonist bexarotene or the PPAR agonist pioglitazone are neuroprotective in mouse models of Alzheimer's disease. Finally we will evaluate the role of the ligand nuclear receptor pathway on HIV induced neurodegeneration using a novel double transgenic mouse model, JR-CSF/hu-CycT1 mice, that permits HIV replication in mouse cells and allows study of how HIV infection induces brain dysfunction. We also plan to develop a novel model for HIV-induced neurodegeneration using latently infected mouse monocytes to repopulate the brains of CD11b-HSVTK transgenic mice where microglial cells have been depleted. The multidisciplinary experiments described in this application represent a comprehensive evaluation of the molecular basis for HIV latency in microglial cells in the brain, the impact of METH on HIV latency and neurodegeneration, and extensive evaluations of the potential of nuclear receptor agonists as neuroprotective agents. We believe that the systematic studies we have proposed here will set the stage for improved clinical management of HIV-associated dementia (HAD) and minor cognitive motor disorder (MCMD) in our patients who abuse drugs.