Role of Gut Microbiome- Brain Axis in Modulating CNS Inflammasomes in the Neuropathology Produced by Opioid Exposure and HIV

摘要/项目摘要 长期使用阿片类药物与肠道微生物失调、肠道屏障破坏和全身细菌有关 易位。肠道渗漏、微生物易位和全身炎症是HIV疾病的特征 进步。近年来，人们对Toll-like的影响进行了大量的研究 小胶质细胞激活和NLRP3炎性小体组装中的受体(TLR)作为持续的机制 神经炎症和神经认知疾病的进展。虽然之前的研究已经调查了 HIV相关毒蛋白(TAT和gp120)和阿片类药物对炎性小体激活的直接作用 小胶质细胞对肠道衍生产物的作用及其对炎症小体激活的影响知之甚少。 和神经认知障碍，这些障碍在使用艾滋病毒患者的实质上很普遍。尽管大多数研究 革兰氏阴性杆菌产生的内毒素水平和细菌产物与炎症和 HIV疾病的进展，最近的研究清楚地显示出明显的革兰氏阳性的丰富和流行 与正常健康人相比，HIV感染者体内的细菌群落。我们的中央 假说是以革兰氏阳性细菌群落的扩张为主导的微生物失调 导致G细菌产物作为小胶质细胞TLR2同源配体的全身性渗漏 导致TLR2激活并诱导炎症体组件组装。我们的中心假设是 得到以下初步数据的支持。在药物滥用的背景下使用艾滋病毒的啮齿动物模型，我们 证明1)肠道细菌移位显著增加，b)全身炎症，c)NLRP3 HIV感染动物的小胶质细胞表达在HIV吗啡中显著加剧 当与它们各自的对照相比时，处理过的动物。2)吗啡诱导的NLRP3表达 在BV2小胶质细胞中观察到TLR2同源配体的存在。我们将检验这一假设-- 微生物区系免疫脑轴激活脑小胶质细胞中的炎症体信号通路，导致 持续的炎症导致阿片类药物滥用HIV感染者手部的神经病理。 目标1：我们将使用无菌的方法来确定肠道微生物区系在小胶质细胞炎症体激活中的作用。 小鼠b)不同的抗生素(革兰氏特异性耗尽)处理的小鼠和c)革兰氏阳性的感染 粪肠球菌。我们还将调查动物的性别是否是小胶质细胞的生物学变量 在艾滋病毒感染背景下，我们的阿片依赖模型中的NLRP3激活。目标2：确定角色 TLR2在组织特异性缺失诱导小胶质细胞NLRP3中的表达 CX3CR1 Cre小鼠小胶质细胞特异性cre的表达。目标3：确定益生菌和 TLR2拮抗剂可减弱NLRP3对小胶质细胞的诱导作用。

Abstract/Project Summary Chronic opioid use is associated with gut microbial dysbiosis, gut barrier disruption and systemic bacterial translocation. Gut leakiness, microbial translocation and systemic inflammation are hallmarks of HIV disease progression. In recent years, much attention has been focused towards elucidating the impact of Toll-like receptors (TLRs) in microglial activation and NLRP3 inflammasome assembly as a mechanism for sustained neuroinflammation and neurocognitive disease progression. While previous studies have investigated the direct effect of HIV associated toxic proteins (TAT and gp120) and opioids on inflammasome activation on microglial little is known about the role of gut derived products and their impact on inflammasome activation and neurocognitive disorders that are prevalent in substance using HIV patients. Although most studies correlate endotoxin levels and bacterial products derived from gram-negative bacteria with inflammation and HIV disease progression, recent studies clearly show a distinct enrichment and prevalence of gram positive bacterial communities in HIV infected patients when compared to normal healthy individuals. Our central hypothesis is that microbial dysbiosis with predominant expansion of Gram positive bacterial communities leading to systemic leakage of G+ bacterial products serve as cognate ligands on TLR2 on microglial cells leading to TLR2 activation and induction of inflammasome components assembly. Our central hypothesis is supported by the following preliminary data. Using a rodent model of HIV in the context of drug abuse, we demonstrate 1) Significant increase in a) gut bacterial translocation b) systemic inflammation c) NLRP3 expression on microglial cells in HIV infected animals that are dramatically exacerbated in HIV+ Morphine treated animals when compared to their respective controls. 2) Morphine induced NLRP3 expression is only observed in the presence of TLR2 cognate ligand in BV2 microglial cells. We will test the hypothesis that gut- microbiota immune brain axis activate inflammasome signaling pathways in brain microglial cells leading to sustained inflammation contributing to the neuropathology of HAND in an opioid abusing HIV infected patients. Aim 1: We will establish the role of the gut microbiota in microglial inflammasome activation using a) germ free mice b) differential antibiotic (gram specific depletion)treated mice and c) infection with gram positive Enterococcus Faecalis. We will also investigate if sex of the animals serves as a biological variable in microglia NLRP3 activation in our model of opioid dependence in the context of HIV infection. Aim 2: Determine the role of TLR2 in NLRP3 induction in microglial cells using tissue specific deletion by breeding floxed TLR2 with microglial specific cre expression using Cx3Cr1 Cre mice. Aim 3: Determine if combination of probiotics and TLR2 antagonist attenuate NLRP3 induction on microglial cells.