Role of pannexin-1 hemichannels in NeuroAIDS

项目摘要： 根据世卫组织和联合国的报告，2014年全球估计有3400万人与 爱滋病毒。除了损害免疫系统外，艾滋病毒还可以在感染早期感染中枢神经系统 疾病，导致破坏性的神经后果(神经艾滋病)。越来越多的证据 表明神经艾滋病的神经损害不是由活跃的病毒复制引发的，而是由 艾滋病毒感染的白细胞向大脑的迁移以及相关的神经炎症。虽然它是 众所周知，艾滋病毒使用宿主编码的蛋白质来促进病毒感染、复制和 移行到中枢神经系统，参与神经艾滋病发病的特定宿主因素仍然存在 人们对此知之甚少。我们的实验室最近发现PAnnexin-1通道是必不可少的 免疫细胞中艾滋病毒生命周期的组成部分以及神经艾滋病的发病机制。在……里面 特别是，我们和其他人已经证明了pAnnexin-1通道的开放促进了多个步骤 艾滋病毒介导的中枢神经系统损害，包括：(1)调节CCR5表面聚集和贩运 对艾滋病毒感染的反应；(2)通过直接调节渠道开放和随后进入艾滋病毒 释放细胞内的ATP，自激活的嘌呤能受体；(3)释放细胞内的因子，如 作为促进炎症的三磷酸腺苷；(4)单核细胞对趋化因子的反应分化和成熟 和/或HIV；(5)白细胞到 跨血脑屏障移行；(6)神经炎症。我们还发现，三磷酸腺苷会损害血脑屏障的完整性 和功能，我们对大量患者样本的分析表明，循环中的ATP可能是 中枢神经系统疾病的生物标志物。我们的初步数据显示，不同的种族群体携带着特定的 PAnnexin-1基因的多态性和该通道的差异表达和开放，潜在地 至少部分原因是观察到的艾滋病毒感染和神经艾滋病易感性的差异 不同的种族。我们最近的初步数据表明，循环中的ATP浓度及其 与中枢神经系统损害的相关性也与种族有关。重要的是，pAnnexin-1通道有 作为治疗靶点的极佳潜力，因为(1)它们的开口可以在体内被有效地阻断 使用几种pAnnexin-1通道阻滞剂，包括我们最近设计的一种特定的模拟肽； (2)这些通道在生理条件下大多以闭合状态存在，使电势最小 副作用。该提案旨在定义将pAnnexin-1通道开放连接到 HIV受体的表达、运输和功能(目标1)、白细胞分化和向 中枢神经系统(AIM 2)，以及通过通道释放的神经炎性因子在BBB和BBB中的作用 中枢神经系统功能(目标3)。最后，在目标4中，我们将研究PAnnexin-1通道在两种动物中的作用 模特们。总之，这些实验将揭示一种重要的新宿主因素在神经艾滋病中的作用。

Project Abstract: According to WHO and UN reports, in 2014 an estimated 34 million persons worldwide were living with HIV. In addition to compromising the immune system, HIV can also infect the CNS early during the disease, leading to devastating neurological consequences (NeuroAIDS). A growing body of evidence indicates that neurological damage in NeuroAIDS is triggered not by the active viral replication but by the transmigration of HIV-infected leukocytes into the brain and the associated neuroinflammation. While it is well established that HIV uses host-encoded proteins to facilitate viral infection, replication and transmigration into the CNS, specific host factors involved in the pathogenesis of NeuroAIDS are still extremely poorly understood. Our laboratory recently identified pannexin-1 channels as essential components of the HIV life cycle in immune cells as well as in the pathogenesis of NeuroAIDS. In particular, we and others have demonstrated that pannexin-1 channel opening facilitates multiple steps of HIV-mediated CNS compromise, including: (1) regulation of CCR5 surface aggregation and trafficking in response to HIV infection; (2) HIV entry by direct regulation of the channel opening and subsequent release of intracellular ATP, auto-activating purinergic receptors; (3) release of intracellular factors such as ATP that promote inflammation; (4) monocyte differentiation and maturation in response to chemokines and/or HIV; (5) increased expression of several adhesion molecules required for leukocytes to transmigrate across the BBB; (6) neuroinflammation. We also found that ATP compromises BBB integrity and function, and our analysis of a large number of patient samples suggests that circulating ATP may be a biomarker of CNS disease. Our preliminary data indicate that different ethnic groups carry specific pannexin-1 polymorphisms and have differential expression and opening of this channel, potentially underlying, at least in part, the observed variation in susceptibility to HIV infection and NeuroAIDS among different ethnicities. Our recent preliminary data indicate that circulating ATP concentrations and their correlation with CNS compromise are also ethnicity related. Importantly, pannexin-1 channels have excellent potential as a therapeutic target because (1) their opening can be effectively blocked in vivo using several pannexin-1 channel blockers, including a specific mimetic peptide we recently designed; and (2) these channels mostly exist in a closed state under physiological conditions, minimizing potential side effects. This proposal is designed to define the mechanisms linking pannexin-1 channel opening to HIV receptor expression, trafficking, and function (Aim 1), leukocyte differentiation and transmigration into the CNS (Aim 2), and the role of neuroinflammatory factors released through the channel in BBB and CNS function (Aim 3). Finally, in Aim 4 we will examine the role of pannexin-1 channels in two animal models. Together, these experiments will reveal the role of an important new host factor in NeuroAIDS.