Viral Protein R (Vpr) in HIV-associated Brain Neuroinflammation and Neurotoxicity

这一提议的项目与退伍军人医疗保健直接相关，因为它涉及退伍军人管理局目前的研究 优先关注HIV-1感染如何导致脑损伤，影响退伍军人的心理健康，包括HIV-1 相关的神经认知障碍(手)和自杀。目前大约有3700万人与 全球范围内的艾滋病毒/艾滋病。成功的联合抗逆转录病毒疗法(CART)可以消除 积极复制病毒，将患者的生命延长到接近正常的寿命。然而，新的挑战是 超过一半的HIV感染和老龄化患者面临的是慢性中枢神经系统炎症，它 通向各式各样的手。虽然重度和进展性手由于CART而显著减少，但慢性 手通常持续存在，导致精神错乱、痴呆症和抑郁症的高发生率，可能导致自杀。 事实上，“艾滋病毒感染者的自杀死亡率是未感染者的3-5倍。 对口单位“。然而，HAND的神经发病机制尚不清楚。 Hand的典型特征是HIV介导的神经胶质炎症和神经毒性。有趣的是， 某些手的严重程度并不总是与艾滋病毒水平直接相关，而是与神经胶质细胞的激活有关， 这表明其他与艾滋病毒相关的因素，而不是整个病毒本身，对这些疾病起到了作用。HIV-1病毒蛋白 R(Vpr)可能是病毒因素之一，因为vpr会导致神经炎症和神经细胞。 细胞凋亡。此外，在CART下没有病毒活跃复制的情况下，可以在与CNS相关的VPR中发现 因为1)它可以直接从病毒颗粒中释放出来；2)它可以穿过血脑屏障， 被神经胶质细胞和神经元摄取；3)通过与LTR结合，触发潜伏感染细胞的病毒转录 推动者。尽管这些强有力的证据表明VPR在手中发挥着突出的作用，但VPR到底是如何 对手部的贡献仍然难以捉摸。这项建议的目的是研究VPR(S)在 宿主神经炎症的激活、神经毒性和病毒再激活，以及其对手部的贡献。 通过我们的初步研究，我们发现艾滋病毒表达和激活 HIV感染者星形胶质细胞中促炎症标志物(TLR4、肿瘤坏死因子α、核因子-κB和Sur1-Trpm4通道)的研究 人和转基因小鼠的死后脑组织。此外，VPR单独激活了相同的一组 神经胶质细胞中的标志物。VPR和Sur1-Trpm4通道之间的连接可能是重要的 因为这一通道是参与各种神经认知大脑的关键神经调节因子 条件。事实上，FDA批准的改变用途的药物格列本脲对该通道的抑制可以减少 VPR诱导细胞凋亡，改善其他神经炎性脑部状况。因此，我们的初步研究可能会 揭示了HAND参与VPR诱导的Sur1-Trpm4通道激活的新机制。因此， 我们假设vpr通过TLR4/MyD88和/或肿瘤坏死因子α介导的NF-κB激活而参与HAND，这是 进而上调Sur1-Trpm4通道，导致神经炎症和神经毒性。或者，VPR- 诱生手是由NF-κB和Sur1-Trpm4介导的神经病理效应共同参与的。我们 进一步假设，靶向特异性抑制关键调控因子，如Sur1-Trpm4通道可以缓解 VPR诱导的手。我们将用三个特定的目标(SA)来检验这些假设。SA1：描绘分子 VPR诱导原代星形胶质细胞神经炎症、神经毒性和病毒重新激活的机制；SA2： 检测VPR与Sur1-Trpm4通道的功能联系、与核因子-kB的相互作用及其在VPR中的作用。 和SA3：评估Sur1-Trpm4基因和药物抑制的效果 利用基因敲除小鼠和靶向特异性治疗药物如 格列本脲。该项目的成功完成将为1)分子机制提供新的见解 以及HIV-1Vpr对Hand的贡献；2)Vpr与Sur1-Trpm4通道之间的功能联系及其 对手的贡献，以及3)治疗药物格列本脲治疗VPR相关手的可行性。

This proposed project has direct relevance to Veteran healthcare because it addresses current VA’s research priority on how HIV-1 infection causes brain damages that affect Veteran’s mental health including HIV- associated neurocognitive disorders (HAND) and suicide. There are about 37 million people currently living with HIV/AIDS worldwide. Successful treatment with combinational antiretroviral therapies (cART) can eliminate active replicating viruses and prolong patients’ lives to nearly normal lifespans. However, the new challenge faced by more than half of those HIV-infected and aging patients is the chronic CNS neuroinflammation, which leads to various HAND. While severe and progressive HAND has decreased significantly due to cART, chronic HANDS often persists, resulting in high rates of delirium, dementia and depression that could lead to suicide. Indeed, “the risk of suicide mortality in HIV-infected persons is 3-5 times higher than in HIV-uninfected counterparts”. Nevertheless, the mechanism of neuropathogenesis underlying HAND is not well understood. HAND is typically characterized by HIV-mediated glial neuroinflammation and neurotoxicity. Interestingly, the severity of some HAND does not always directly correlate with the levels of HIV, but rather with glial activation, suggesting other HIV-associated factors, not the whole virus per se, contribute to those HAND. HIV-1 viral protein R (Vpr) might be one of those viral factors, because Vpr induces neuroinflammation and causes neuronal apoptosis. Moreover, in the absence of active viral replication under cART, Vpr can be found in CNS-associated cells because 1) it can be released directly from viral particles; 2) it crosses the blood-brain barrier that can be taken up by glia and neurons; and 3) it triggers viral transcription of latently-infected cells by binding to LTR promoter. Despite these strong evidences indicating a prominent role of Vpr in HAND, how exactly Vpr contributes to HAND remains elusive. The objective of this proposal is to study the specific role(s) of Vpr in activation of host neuroinflammation, neurotoxicity and viral reactivation, as well as its contribution to HAND. Through our pilot studies, we discovered correlations between HIV expression and activation of proinflammatory markers (TLR4, TNFα, NF-κB and the Sur1-Trpm4 channel) in astrocytes of HIV-infected postmortem human and transgenic mouse brain tissues. Furthermore, Vpr alone activate the same set of markers in glial cells. The connection between Vpr and the Sur1-Trpm4 channel could potentially be significant for understanding HAND because this channel is a key neuro-regulator involved in various neurocognitive brain conditions. Indeed, inhibition of the channel by a repurposed and FDA-approved drug glibenclamide reduces Vpr-induced apoptosis and improves other neuroinflammatory brain conditions. Thus, our pilot studies may have revealed a novel mechanism of HAND involving Vpr-induced activation of the Sur1-Trpm4 channel. Therefore, we hypothesize that Vpr contributes to HAND by TLR4/MyD88- and/or TNFα-mediated NF-κB activation, which in turn upregulate the Sur1-Trpm4 channel leading to neuroinflammation and neurotoxicity. Alternatively, Vpr- induced HAND is contributed collectively by NF-κB and Sur1-Trpm4-mediated neuropathologic effects. We further hypothesize that target-specific inhibition of key regulators such as the Sur1-Trpm4 channel mitigates Vpr-induced HAND. We will test these hypotheses with three specific aims (SA). SA1: delineate molecular mechanism of Vpr-induced neuroinflammation, neurotoxicity and viral reactivation in primary astrocytes; SA2: test the functional link of Vpr with the Sur1-Trpm4 channel, its interaction with NF-kB and its contribution to Vpr- induced HAND; and SA3: evaluate the effects of genetic and pharmacologic inhibitions of the Sur1-Trpm4 channel on Vpr-induced HAND by using knock-out mice and by target-specific therapeutic drugs such as glibenclamide. Successful completion of this project will provide novel insights into 1) the molecular mechanism and contribution of HIV-1 Vpr to HAND, 2) the functional link between Vpr and the Sur1-Trpm4 channel and its contribution to HAND, and 3) the feasibility of treating Vpr-related HAND with the therapeutic drug glibenclamide.