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

项目摘要 来自艾滋病毒携带者(PLWH)的脑组织显示出阿尔茨海默病(AD)样病理的证据， 包括神经毒性淀粉样蛋白b增加(Ab40/42)、淀粉样斑块和Tau过度磷酸化(Ptau) 与神经变性和艾滋病毒相关的神经认知障碍(手)有关。其作用机制 HIV通过增加抗体、ptau和诱导AD样中枢神经系统(CNS)损害而不是 为人所知。尽管大多数有CNS抗体斑块和ptau的PLWH已经接受了长期的抗逆转录病毒治疗(ART)， ART在ptau和Ab的产生以及AD样病理中的作用尚未被研究。调查结果来自 我们的R21研究，使用体外、体内和体外方法，证明HIV-1显著增加 CNS AB42和ptau在人源化小鼠中的表达，这与1)显著增加的表达和 β-分泌酶-1(BACE1)、可溶性(S)APPB(淀粉样变通路效应物)和GSK3b的激活/活性 (使Tau磷酸化的激酶)；2)Neprilysin(NEP，抗体降解酶)的表达/活性降低；3) 晚期糖基化终产物受体(RAGE， 介导抗体CNS内流)，并降低低密度脂蛋白受体相关蛋白-1的BBB表达 (4)增加神经炎症、神经元损伤和血脑屏障损伤。我们 证实LRP1和CCR5介导抗体通过血脑屏障转运，AZT增强HIV诱导的 上调/激活BACE1、sAPPB和GSK3b，AZT可阻断NEP的表达/活性。 值得注意的是，CCR5拮抗剂马拉韦罗(Maraviroc，MVC)消除了HIV和AZT诱导的这些效应。 因此，我们假设CCR5通过LRP1在抗体的形成、运输和分解代谢中发挥主要作用， PLWH中淀粉样蛋白的发生和ptau，靶向CCR5可以预防HIV诱导的抗体和ptau， 增加抗中枢神经系统的外流，消除中枢神经系统损伤和手部损伤。使用经过验证的艾滋病毒/艾滋病动物模型， 原代人类细胞和人脑组织，我们将检验这一假设并进一步研究 常用抗逆转录病毒药物(AZT、TDF)对HIV诱导的BACE1和APP激活的影响 淀粉样蛋白生成途径、牛磺酸代谢和中枢神经系统损伤(AIM-1)；抗体转运、降解、清除和 神经炎症(AIM-2)；以及相关的血脑屏障转录和表观基因组特征(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 增加抗体的产生或ii)通过干扰LRP1介导的抗体的运输、降解、清除；iii) 抗逆转录病毒药物的作用；iv)CCR5是否调节这些效应；v)表征脑血管转录组 表观基因组与HIV/ARVS诱导的调节失调和MVC保护作用相关。我们的建议 研究具有高度的影响和翻译意义，并解决了NIH重点关注的高优先级研究领域 关于“在抗逆转录病毒治疗…的背景下研究艾滋病毒引起的中枢神经系统功能障碍的病理生理机制”和 开发新的治疗方法，以减少艾滋病毒感染的中枢神经系统并发症。“

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.”