AIM(2)ing at the inflammasome: Impact of MAVS signaling in cocaine-and HIV-1 induced neuroinflammation

项目摘要/摘要 可卡因是美国使用量第二大的非法药物，它降低了中枢神经系统对艾滋病毒-1的免疫反应，增加了 HIV-1介导的神经毒性的严重程度和发病。星形胶质细胞是抵抗毒性的第一道防线 在中枢神经系统中，并在可卡因暴露后启动对艾滋病毒-1的炎症反应和抗病毒活动(33)； 然而，不受控制的炎症和未能控制艾滋病毒-1复制是一个持续存在的问题。 线粒体抗病毒信号蛋白(MAVS)与黑色素瘤缺失2(AIM2)样受体 炎症体、它们的相互作用、串扰和双支架可能是触发的关键机制 可卡因和HIV-1中的炎症和抗病毒信号。星形胶质细胞暴露可卡因，增加 干扰素(IFN)(33)和干扰素刺激反应元件(ISRE)的活性，推测是通过MAV。我们 证实可卡因引起线粒体毒性，线粒体毒性调节MAVS功能和AIM2炎症体 激活(30，77)。我们发现星形胶质细胞中的可卡因暴露是AIM2启动的主要调节因素 通过caspase-1裂解和AIM2水平的增加来衡量，干扰素刺激基因(ISG)(32，88)。 此外，MAVS在可卡因诱导的AIM2启动中起着至关重要的作用，这在MAVS中得到了证实 下调的星形胶质细胞。MAV和AIM2的双重过度激活会导致慢性炎症病理， 通过核因子κB信号和干扰素的产生(16，23)。我们证实，反复接触可卡因减少了 MAV切割产物并增加MAV聚集性，这是决定干扰素和核因子κB信号的差异因素， 检测细胞因子/趋化因子水平升高，干扰素β水平下降。有趣的是，AIM2结合伙伴， 接头相关的斑点样蛋白(ASC)，通过caspase招募结构域(CARD)与MAV结合 抑制MAVS诱导的干扰素产生的同型相互作用(35)。ASC受由以下因素启动的激酶的调节 MAVS和干扰素信号转导(36，37)，并可能在促进AIM2诱导的异常中发挥重要作用 可卡因和HIV-1中的神经炎症和MAVS抗病毒信号减少。 我们假设可卡因通过线粒体毒性、启动作用促进MAV激活 AIM2炎性小体。反复接触可卡因和/或HIV-1，导致ASC双重招募到 星形胶质细胞MAVS/AIM2。ASC招募启动信号转导事件，触发星形胶质细胞- 诱导炎症和减少抗病毒信号，促进星形胶质细胞诱导的神经毒性 可卡因和HIV-1。为了验证这一假设，我们将揭示可卡因引起AIM2的机制 通过激活星形胶质细胞MAVS激活炎症小体(目标1)；描绘星形胶质细胞MAVS和AIM2支架 和串扰对AIM2炎症体寡聚和信号转导的影响(目标2)；并探讨 星形胶质细胞ASC在AIM2信号中的调节/募集和减弱可卡因和HIV-1中MAVS的激活。 反复接触可卡因和/或随后感染HIV-1会淹没先天免疫反应。 产生高免疫力并降低抗病毒表型，增加艾滋病毒-1神经毒性的风险。

Project Summary/Abstract Cocaine, the second highest used illegal drug in the US, reduces CNS immune responses to HIV-1, increasing the severity and onset of HIV-1-mediated neurotoxicity. Astrocytes are the first line of defense against toxicity in the CNS and initiate inflammatory responses to HIV-1 and antiviral activity following cocaine exposure (33); however, uncontrolled inflammation and the failure to control HIV-1 replication is a continued problem. Mitochondrial antiviral signaling protein (MAVS), together with absent in melanoma 2 (AIM2)-like receptor inflammasomes, their interactions, crosstalk and dual scaffolding could be key mechanisms triggering inflammatory and antiviral signaling in cocaine and HIV-1. Cocaine exposure in astrocytes, increases interferons (IFNs) (33) and activity of the IFN stimulated response element (ISRE), presumably via MAVS. We identified that cocaine induced mitochondrial toxicity, which regulates MAVS function and AIM2 inflammasome activation (30, 77). We discovered that cocaine exposure in astrocytes is a major regulator of AIM2 priming measured by increased caspase-1 cleavage and AIM2 levels, an IFN stimulated gene (ISG) (32, 88). Furthermore, MAVS plays a crucial role in cocaine induced AIM2 priming as demonstrated in MAVS downregulated astrocytes. Dual overactivation of MAVS and AIM2 produce chronic inflammatory pathologies, via NFκB signaling and IFN production (16, 23). We established that repeated cocaine exposure reduced MAVS cleaved products and increased MAVS aggregation, which differentially dictate IFN and NFκB signaling, and we measured increased cytokines/chemokines and decreased IFNβ. Interestingly, AIM2 binding partner, adaptor associated speck-like protein (ASC), binds MAVS via caspase recruitment domain (CARD)-CARD homotypic interactions to inhibit MAVS-induced IFN generation (35). ASC is regulated by kinases initiated by MAVS and IFN signaling (36, 37) and may play a vital role in promoting AIM2-induced aberrant neuroinflammation and reduced MAVS antiviral signaling, in cocaine and HIV-1. We hypothesize that cocaine promotes MAVS activation via mitochondrial toxicity, priming AIM2 inflammasomes. Repeated cocaine exposure, and/or HIV-1, results in dual recruitment of ASC to astrocyte MAVS/AIM2. ASC recruitment initiates signal transduction events triggering astrocyte- induced inflammation and decrease antiviral signaling, promoting astrocyte-induced neurotoxicity in cocaine and HIV-1. To test this hypothesis we will uncover mechanisms by which cocaine cause AIM2 inflammasome priming via astrocyte MAVS activation (Aim 1); delineate astrocyte MAVS and AIM2 scaffolding and crosstalk on AIM2 inflammasome oligomerization and signaling (Aim 2); and explore the impact of astrocyte ASC regulation/recruitment in AIM2 signaling and attenuated MAVS activation in cocaine and HIV-1. Repeated cocaine exposure, and/or subsequent introduction of HIV-1, inundates the innate immune response producing a hyperimmuno and decreased antiviral phenotype, increasing the risk of HIV-1 neurotoxicity.