Blood brain barrier immune compromise in NeuroAIDS

摘要： 血脑屏障(BBB)的损害在HIV-1感染者中很常见，并与 HIV-1相关性痴呆的发病机制。这一屏障的后盾允许后代病毒和激活的HIV-1- 感染的巨噬细胞渗入大脑，将病毒传播到血管周围的巨噬细胞和小胶质细胞。 大脑中受感染的细胞分泌神经毒素，影响神经元功能，导致认知障碍。 因此，阻止血脑屏障损伤是预防HIV-1感染后神经损伤的主要手段。至 要做到这一点，就需要阐明HIV感染导致血脑屏障功能障碍的机制。 使用定义的平台，整合基因组学、蛋白质组学和细胞生物系统，我们最近 证实HIV-1感染的巨噬细胞与人脑微血管内皮细胞接触并刺激 促炎症细胞因子和趋化因子的自分泌和旁分泌级联反应，最终影响 BBB的结构和完整性。我们的初步工作，在体外，并使用艾滋病毒的脑微血管- 感染人类，表明HIV-1诱导了人脑内皮细胞的炎症和损伤 涉及丝氨酸727处的STAT1的激活。我们进一步证明了氟达拉滨，一种特定的STAT1 抑制，减少炎症和病毒感染性，减少病毒血症，胶质增生和巨噬细胞浸润 HIV脑炎小鼠的大脑。基于这些观察，我们的假设是STAT1发挥了关键作用 在HIV-1诱导的血脑屏障功能障碍和调节巨噬细胞-内皮相互作用中的作用。我们 假设通过影响STAT1通路，血脑屏障功能障碍可以逆转，从而产生保护作用 屏障的完整性。这一假设将在以下具体目标中得到解决：在目标1中，我们将 研究HIV-1和病毒诱导的细胞因子对内皮细胞骨架的影响，并破译 STAT-1在这些改变中的作用。这是基于我们的初步观察，艾滋病毒-1感染 巨噬细胞炎症反应改变内皮细胞骨架。在目标2中，我们将调查 STAT1在HIV感染背景下内皮细胞功能和内皮-巨噬细胞相互作用中的作用。 最后，在目标3中，我们将测试我们的假设，即STAT1在体内介导艾滋病毒诱导的血脑屏障损伤，使用 HIV-1脑炎动物模型的建立。这些研究将为深入了解细胞因子 艾滋病毒在血脑屏障传递信号，这是艾滋病毒感染时发生的失调，并导致血脑屏障功能障碍。相关性： 目前世界上有4000万人感染艾滋病毒/艾滋病，神经系统并发症有 在这些感染者中很常见。HIV侵入大脑，破坏大脑内皮细胞，然后 感染脑巨噬细胞，损伤神经元，导致认知障碍，有时还会痴呆。这个 这项提案的工作将帮助我们了解艾滋病毒是如何损害大脑内皮并进入大脑的， 如何防止病毒进入大脑，以及艾滋病毒相关痴呆症。

Abstract: Blood-brain barrier (BBB) compromise is common in HIV-1-infected individuals and is implicated in the pathogenesis of HIV-1-associated dementia. Breech of this barrier allows progeny virus and activated, HIV-1- infected macrophages to infiltrate the brain, disseminate virus to perivascular macrophages and microglia. Infected cells in the brain secrete neurotoxins that affect neuronal function and lead to cognitive impairments. Therefore, a principal means to prevent neurological injury following HIV-1 infection is to halt BBB injury. To accomplish this, the mechanisms through which HIV infection leads to BBB dysfunction need be elucidated. Using a defined platform, integrating genomics, proteomics and cell biological systems, we recently demonstrated that HIV-1-infected macrophages engage human brain microvascular endothelial cells and incite an autocrine and paracrine cascade of pro-inflammatory cytokines and chemokines that ultimately affect the structure and integrity of the BBB. Our preliminary work, in vitro and using brain microvessels from HIV- infected humans, demonstrated that HIV-1-induced inflammation and injury to human brain endothelial cells involve activation of STAT1 at serine 727. We further demonstrated that Fludarabine, a specific STAT1 inhibitor, reduced inflammation and viral infectivity, reduced viremia, gliosis and macrophage infiltration in the brain of HIV encephalitic mice. Based on these observations, it is our hypothesis that STAT1 play a critical role in HIV-1-induced BBB dysfunction and modulates macrophage-endothelial interactions. We hypothesize that by affecting STAT1 pathways, BBB dysfunction can be reversed leading to protection of the barrier's integrity. This hypothesis will be addressed in the following specific aims: in Aim 1, we will investigate the effects of HIV-1 and viral-induced cytokines on the endothelial cytoskeleton, and decipher the role of STAT-1 on these alterations. This is based on our preliminary observation that HIV-1-infected macrophage inflammatory responses alter the endothelial cytoskeleton. In Aim 2, we will investigate the role of STAT1 in endothelial cell function and endothelial-macrophage interaction in the context of HIV infection. Finally in Aim 3, we will test our hypothesis that STAT1 mediates HIV-induced BBB injury in vivo, using an animal model of HIV-1 encephalitis. These studies will provide insight into the mechanisms by which cytokines and HIV transduce signals at the BBB, dysregulations that occurs in HIV infection and lead to BBB dysfunction. Relevance: Forty-million people in the world are currently living with HIV/AIDS; and neurological complications are common among these infected individuals. HIV infiltrates the brain damaging the brain endothelium, then infects brain macrophages and injures neurons, resulting in cognitive deficits and sometimes dementia. The work in this proposal will help us understand how HIV damages the brain endothelium and enters the brain, how to prevent viral entry into the brain, and HIV-associated dementia.