Molecular mechanisms underlying HIV & Cocaine-mediated microglial activation: Targeting NLRP3 inflammasome

HIV的分子机制

• 批准号: 10161058
• 负责人: Shilpa J. Buch
• 金额: $ 10.78万
• 依托单位: UNIVERSITY OF NEBRASKA MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-09-30 至 2024-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10161058
• 关键词: Affect; Astrocytes; Behavior assessment; Binding; Blood - brain barrier anatomy; Brain; CASP1 gene; Caspase; Cells; Cocaine; Cocaine Abuse; Complex; Data; Development; Disease; Down-Regulation; Drug abuse; Enzyme-Linked Immunosorbent Assay; Exposure to; Future; Gene Silencing; Genetic Transcription; HIV; HIV-associated neurocognitive disorder; Human; IL18 gene; Immune; In Vitro; Individual; Inflammasome; Inflammatory Response; Interleukin-1 beta; Leucine-Rich Repeat; Mediating; Memory; Messenger RNA; MicroRNAs; Microglia; Molecular; Motor Activity; Multiprotein Complexes; Mus; Neurocognitive; Neurocognitive Deficit; Neuroglia; Nuclear Translocation; Nucleotides; Pathway interactions; Pharmacology; Phosphorylation; Prevalence; Process; Proteins; Quality of life; Reactive Oxygen Species; Rodent; Rodent Model; Role; Signal Pathway; Signal Transduction; Site; Testing; Time; Trans-Activators; Transgenic Organisms; Up-Regulation; Western Blotting; antiretroviral therapy; base; combinatorial; comorbidity; cytokine; cytotoxic; efficacy testing; in vivo; inhibitor/antagonist; neuroinflammation; novel therapeutics; response; symptomatology

Abstract: In the current era of combination antiretroviral therapy (cART), there is increased prevalence of HIV-associated neurocognitive disorders (HAND) with about 30-50% of HIV-infected individuals afflicted with varying degrees of neurocognitive impairments, substantially affecting their quality of life. It is well-recognized that despite cART, there is unabated persistence & presence of early HIV protein(s) such as the cytotoxic transactivator of transcription (TAT), that contributes to neuroinflammation. Adding fuel to the mix is the comorbidity of drug abuse in HIV-infected individuals, which further exacerbates microglial activation & thus symptomatology of HAND. Until recently, CNS was considered as an immune-privileged site, however, a recent paradigm shift in our understanding has revealed the role of cytosolic, multiprotein complexes, belonging to the nucleotide-binding domain leucine-rich repeat containing (NLR) protein superfamily, termed as “inflammasomes,” in various neuroinflammatory diseases. Assembly of these multiprotein complexes activates the proinflammatory caspases (specifically caspase 1), leading, in turn, to the cleavage & release of IL1β & 1L18, consequently resulting in a potent inflammatory response. Among the various NLRs, NLRC5 & NLRP3 are highly expressed in microglia & differentially regulate inflammatory responses. In our efforts to understand the combinatorial effects of HIV Tat & cocaine on Mg activation, we have made several exciting preliminary observations: 1) Exposure of rodent primary Mg to both HIV Tat & cocaine demonstrated significantly downregulated expression of NLRC5, with a concomitant upregulation of NLRP3 and, exacerbated Mg activation compared to cells exposed to either agent alone; 2) Rodent Mg exposed to HIV TAT demonstrated time-dependent upregulation of microRNA (miR)-34a, leading, in turn, to downregulation of its target - NLRC5; 3) Cocaine-mediated activation of Mg involved induction of reactive oxygen species (ROS), that was accompanied with defective mitophagy & subsequent oligomerization of NLRP3 inflammasome complex, leading to induced expression of mature (m)IL1β & IL18; 4) NLRP3 inhibitor - MCC950 mitigated cocaine-mediated activation of Mg. Based on these observations, we hypothesize that the co-operative effects of HIV TAT & cocaine on Mg activation involve two processes: a) downregulated expression of NLRC5 resulting in activation of NFκB (signal 1), leading, in turn, to transcriptional upregulation of NLRP3, pro IL1β & IL18, & b) induction of ROS-mediated defective mitophagy (signal 2), which, in turn, induces activation of NLRP3 inflammasome, resulting in increased cleavage & secretion of mIL1β & IL18. The hypothesis will be tested in two SA: 1) Explore the molecular mechanism(s) underlying HIV & cocaine- mediated induction of the NLRP3 inflammasome leading to Mg activation and 2) To validate in vivo the role of NLRC5/NFκB & ROS/defective mitophagy/NLRP3 axes underlying HIV Tat & cocaine-mediated activation of Mg. Understanding the mechanisms responsible for microglial activation induced by HIV & cocaine will set the stage for the future development of novel therapeutics aimed at dampening the neuroinflammatory responses.

抽象的： 在当前的抗逆转录病毒疗法（CART）的时代，与HIV相关的患病率增加 大约30-50％感染不同程度的HIV感染者的神经认知障碍（手） 神经认知障碍，其次影响其生活质量。众所周知，欲望购物车， 早期HIV蛋白（例如的细胞毒性反式激活因子）的持久性和存在 转录（TAT），导致神经炎症。添加燃料的混合物是药物滥用的合并症 在艾滋病毒感染的个体中，这进一步加剧了小胶质激活，从而加剧了手的症状。 直到最近，CNS仍被认为是一个免疫特性部位，但是，我们最近的范式转移了我们 理解揭示了属于核苷酸结合的胞质，多蛋白复合物的作用 含有域亮氨酸的重复含有（NLR）蛋白超家族，称为“炎症”，在各种 神经炎症性疾病。这些多蛋白络合物的组装激活促炎胱天蛋白酶 （特别是caspase 1），反过来，导致IL1β和1L18的裂解和释放，从而导致A 潜在的炎症反应。在各种NLR中，NLRC5和NLRP3在小胶质细胞中高度表达 差异调节炎症反应。在我们了解HIV TAT的组合作用的努力中 ＆可卡因在MG激活中，我们进行了几个令人兴奋的初步观察：1）啮齿动物的暴露 对HIV TAT和可卡因的一级MG表现出明显下调NLRC5的表达， 与暴露于任何一种药物的细胞相比 独自的; 2）暴露于HIV TAT的啮齿动物MG显示了MicroRNA（MIR）-34A的时间依赖性更新 反过来，领先于其目标-NLRC5的下调； 3）可卡因介导的Mg激活涉及诱导 伴随有缺陷的线粒体和随后的活性氧（ROS） NLRP3炎性体复合物的寡聚化，导致成熟（M）IL1β和IL18的诱导表达； 4） NLRP3抑制剂-MCC950减轻可卡因介导的Mg激活。基于这些观察，我们 假设HIV TAT和可卡因对MG激活的合作作用涉及两个过程：A） NLRC5的下调表达，导致NFκB激活（信号1），依次导致转录 NLRP3，ProIL1β和IL18的上调，＆b）诱导ROS介导的有缺陷的线粒体（信号2） 反过来，诱导NLRP3炎性体的激活，从而导致MIL1β和IL18的裂解和分泌增加。 该假设将在两个SA中进行检验：1）探索HIV和可卡因基础的分子机制 NLRP3炎性体的介导导致MG激活的诱导和2）在体内验证的作用 NLRC5/NFκB和ROS/有缺陷的线粒体/NLRP3轴为HIV TAT和可卡因介导的Mg的激活。 了解艾滋病毒和可卡因引起的小胶质细胞激活的机制将设定阶段 为了使新疗法的未来发展旨在减弱神经炎症反应。