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

项目总结/摘要 可卡因是美国使用量第二高的非法药物，可降低CNS对HIV-1的免疫反应， HIV-1介导的神经毒性的严重程度和发作。星形胶质细胞是抵御毒性的第一道防线 在中枢神经系统和启动炎症反应的HIV-1和抗病毒活性后，可卡因暴露（33）; 然而，不受控制的炎症和不能控制HIV-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（AIM 2）样受体 炎性小体，它们之间的相互作用，串扰和双重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。星形胶质细胞中的皮质醇暴露，增加 干扰素（IFN）（33）和IFN刺激的反应元件（ISRE）的活性，推测是通过MAVS。我们 确定可卡因诱导线粒体毒性，其调节MAVS功能和AIM 2炎性体 激活（30，77）。我们发现，星形胶质细胞中的可卡因暴露是AIM 2启动的主要调节因子。 通过增加的半胱天冬酶-1切割和AIM 2水平来测量，IFN刺激基因（ISG）（32，88）。 此外，MAVS在可卡因诱导的AIM 2启动中起关键作用，如MAVS中所示。 下调星形胶质细胞。MAVS和AIM 2的双重过度活化产生慢性炎症病理， 通过NFκB信号传导和IFN产生（16，23）。我们确定了重复接触可卡因 MAVS切割产物并增加MAVS聚集，这差异性地决定了IFN和NFκB信号传导， 我们检测到细胞因子/趋化因子增加和IFNβ减少。有趣的是，AIM 2结合伴侣， 衔接子相关斑点样蛋白（ASC），通过半胱天冬酶募集结构域（CARD）结合MAVS-CARD 同型相互作用以抑制MAVS诱导的IFN产生（35）。ASC受以下激酶的调节： MAVS和IFN信号传导（36，37），并可能在促进AIM 2诱导的异常细胞凋亡中发挥重要作用。 神经炎症和减少MAVS抗病毒信号，在可卡因和HIV-1。 我们假设可卡因通过线粒体毒性、引发和激活MAVS来促进MAVS激活。 AIM 2炎性小体。反复接触可卡因和/或HIV-1，导致ASC的双重招募， 星形胶质细胞MAVS/AIM 2。ASC募集启动信号转导事件，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AIM 2的机制。 通过星形胶质细胞MAVS激活引发炎性小体（Aim 1）;描述星形胶质细胞MAVS和AIM 2支架 和串扰对AIM 2炎性小体寡聚化和信号传导（Aim 2）的影响;并探讨 星形胶质细胞ASC调节/募集AIM 2信号传导和减弱可卡因和HIV-1中的MAVS活化。 反复接触可卡因和/或随后引入HIV-1，淹没先天免疫反应 产生超免疫和降低的抗病毒表型，增加HIV-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.