PREVENTING ALZHEIMER’S DISEASE-LIKE BRAIN PATHOLOGY IN HIV INFECTION BY TARGETING CCR5

项目摘要 来自艾滋病毒感染者（PLWH）的脑组织显示出阿尔茨海默病（AD）样病理的证据， 包括增加的神经毒性淀粉样蛋白-b（Ab40/42）、淀粉样蛋白斑块和Tau过度磷酸化（pTau） 与神经变性和HIV相关的神经认知障碍（HAND）相关。的机制 HIV增加Ab、pTau和诱导AD样中枢神经系统（CNS）损害的途径， 知道的尽管大多数患有CNS Ab斑块和pTau的PLWH一直在接受长期抗逆转录病毒治疗（ART）， ART在pTau和Ab产生以及AD样病理中的作用尚未研究。的结果 我们使用体外、体内和离体方法进行的R21研究表明， CNS Ab42和pTau在人源化小鼠中的表达显著增加，并且这与1）显著增加的表达和 b-分泌酶-1（BACE1）、可溶性APPb（淀粉样蛋白生成途径效应物）和GSK 3b的活化/活性 （磷酸化Tau的激酶）; 2）降低脑啡肽酶（NEP，Ab降解酶）的表达/活性; 3） 晚期糖基化终末产物受体的血脑屏障（BBB）表达增加（ESTA， 介导Ab CNS流入），并降低BBB低密度脂蛋白受体相关蛋白-1的表达 (LRP1介导CNS Ab流出）;和4）增加的神经炎症、神经元损伤和BBB损伤。我们 表明LRP 1和CCR 5介导抗体转运通过血脑屏障，AZT增强HIV诱导的 AZT能抑制NEP的表达/活性，而BACE1、sAPPb和GSK3b的表达/活性则被AZT阻断。 值得注意的是，CCR5拮抗剂马拉韦罗（MVC）消除了这些HIV和AZT诱导的作用。 因此，我们假设CCR5通过LRP 1在抗体形成、转运和催化中起主要作用， PLWH中的淀粉样蛋白生成和pTau，并且靶向CCR5防止HIV诱导的Ab和pTau， 增加Ab CNS流出，消除CNS损伤和HAND。使用经验证的HIV/AIDS动物模型， 原代人类细胞和人脑组织，我们将测试这一假设，并进一步研究的影响， 常用抗逆转录病毒（ARV）药物（AZT、TDF）对HIV诱导的BACE1和APP激活的影响 淀粉样蛋白生成途径、Tau代谢和CNS损伤（Aim-1）; Ab转运、降解、清除和 神经炎症（Aim-2）;以及相关的BBB转录组和表观基因组标记（Aim-3）。这些 机制研究将有助于确定HIV是否通过i）激活BACE1通路诱导淀粉样蛋白生成 增加Ab产生或ii）通过干扰LRP 1介导的Ab转运、降解、清除; iii） ARV的作用; iv）CCR5是否调节这些作用;以及v）表征脑血管转录组 表观基因组与HIV/ARV诱导的失调和MVC保护作用有关。我们提出的 这些研究具有高影响力和转化意义，并涉及NIH高度优先的研究领域， 关于"在ART背景下检查HIV诱导的CNS功能障碍的病理生理机制. 开发新的治疗方法，以减轻HIV感染的CNS并发症。

PROJECT ABSTRACT Brain tissues from people living with HIV (PLWH) showed evidence of Alzheimer’s Disease (AD)-like pathologies, including increased neurotoxic amyloid-b (Ab40/42), amyloid plaques and Tau hyperphosphorylation (pTau) associated with neurodegeneration and HIV-associated neurocognitive disorders (HAND). The mechanisms through which HIV increase Ab, pTau, and induce AD-like central nervous system (CNS) impairment are not known. Although most PLWH with CNS Ab plaques and pTau had been on long-term antiretroviral therapy (ART), the role of ART in pTau and Ab production, and AD-like pathologies has not been investigated. Findings from our R21 studies, using in vitro, in vivo and ex vivo approaches, demonstrated that HIV-1 significantly increased CNS Ab42 and pTau in humanized mice, and this was associated with significantly 1) increased expression and activation/activity of b-secretase-1 (BACE1), soluble (s)APPb (amyloidogenic pathway effectors), and GSK3b (kinase that phosphorylates Tau); 2) reduced expression/activity of neprilysin (NEP, Ab-degrading enzyme); 3) increased blood-brain barrier (BBB) expression of the receptor for advanced glycation end products (RAGE, mediates Ab CNS influx), and reduced BBB expression of low-density lipoprotein receptor–related protein-1 (LRP1, mediates CNS Ab efflux); and 4) increased neuroinflammation, neuronal damage and BBB injury. We demonstrated that LRP1 and CCR5 mediated Ab transport through the BBB, that AZT potentiated HIV-induced upregulation/activation of BACE1, sAPPb and GSK3b, and that AZT blocked NEP expression/activity. Significantly, the CCR5 antagonist maraviroc (MVC) abrogated these HIV- and AZT- induced effects. Thus, we hypothesize that CCR5, via LRP1, plays a major role in Ab formation, transport, and catabolism, amyloidogenesis and pTau in PLWH, and that targeting CCR5 prevents HIV-induced Ab and pTau, increases Ab CNS efflux, and abrogates CNS injury and HAND. Using a validated HIV/AIDS animal model, primary human cells and human brain tissues, we will test this hypothesis and further investigate the effects of commonly prescribed antiretroviral (ARV) drugs (AZT, TDF) on HIV-induced activation of BACE1 and APP amyloidogenic pathway, Tau metabolism, and CNS injury (Aim-1); Ab transport, degradation, clearance, and neuroinflammation (Aim-2); and associated BBB transcriptomic and epigenomic signatures (Aim-3). These mechanistic studies will help determine whether HIV induces amyloidogenesis by i) activating BACE1 pathways to increase Ab production or ii) by interfering with LRP1-mediated Ab transport, degradation, clearance; iii) the role of ARVs; iv) whether CCR5 modulates these effects; and v) characterize the brain vascular transcriptome and epigenome associated with HIV/ARVs-induced dysregulation and MVC protective effects. Our proposed studies are of high-impact, translational significance, and address the NIH high priority research areas that focus on “Examining the pathophysiologic mechanisms of HIV-induced CNS dysfunction in the setting of ART…and development of novel therapeutic approaches to mitigate CNS complications of HIV infection.”