Glial origins of HIV and opiate-driven synaptodendritic injury

说明(申请人提供)：药物滥用和艾滋病毒/艾滋病是相互关联的流行病，因为艾滋病毒-1通过共用针头和通过性交换毒品增加了传播。在过去的十年中，我们已经提出，除了外周免疫失调外，阿片类药物还通过直接作用于阿片受体表达(MOR)神经元和神经胶质细胞，加剧了HIV在中枢神经系统的病理效应。由于MOR在神经元、星形胶质细胞、小胶质细胞和内皮细胞中作用的复杂性和相互关联性，中枢神经系统可能更容易受到阿片类药物和HIV-1相互作用的影响。我们最近报道，Tat或gp120和吗啡的汇聚性神经毒性作用很大程度上是由于MOR+神经胶质细胞的作用。我们在体内的工作支持神经胶质细胞在亚致死性/致死性突触树突状细胞损伤中的核心作用。吗啡加重表达TAT的小鼠海马体和纹状体的结构和功能异常，包括脊椎丢失和突触树突损伤。与吗啡和gp120的神经毒性相互作用是HIV毒株特有的。暴露于活的或紫外线灭活的R5嗜性HIV-1SF162病毒粒子的单核细胞培养液对神经元有毒性；CCR5拮抗剂马拉韦罗可显著减弱这种毒性。我们假设，阿片剂诱导的HIV毒性加剧是通过小胶质细胞、星形胶质细胞和神经元之间的不同CCR5信号来调节的，这可以根据上下文损伤或保护神经元。我们认为阿片类药物与TAT或HIV在肿瘤坏死因子下游相互作用，以促进星形胶质细胞释放炎性趋化因子。特别是，阿片类药物和TAT/HIV的融合效应似乎扰乱了CCL5/CCR5信号，创造了促进小胶质细胞运动和螺旋式激活小胶质细胞的环境。我们的假设在3个目标上进行了测试，以检验星形胶质细胞和小胶质细胞在驱动神经毒性阿片类药物-HIV相互作用中的单独作用。目标1和2使用小鼠模型：a)细胞死亡和亚致死性神经退行性变化的长期、重复成像；b)活体研究，以检测种群变化、神经元病理和行为缺陷。模型包括细胞特异性Cre-lox消融MOR的小鼠，以及可诱导的TAT转基因小鼠与CCL5-/-或CCR-/-小鼠杂交。在目标3中，我们使用人脑胶质细胞和神经元来研究HIV引起的神经退行性改变以及与CCL5-CCR5信号相关的阿片效应。使用活的和灭活的病毒以及突变的病毒株对CCR5激活的感染/非感染效应进行分类。CCR5途径与HIV特别相关。CCR5是M嗜性毒株的HIV共同受体；CCR5基因多态性影响疾病易感性；CCR5拮抗剂马拉韦罗在临床上减缓HIV的进展。研究对于提供治疗策略是必不可少的。通过确定每种神经胶质类型如何导致CCL5/CCR5失调，可以设计明智的细胞和途径特定的措施，以防止阿片剂和艾滋病毒共同暴露的神经毒性后遗症。

DESCRIPTION (provided by applicant): Drug abuse and HIV/AIDS are interlinked epidemics because of increased spread of HIV-1 through needle sharing and through the exchange of sex for drugs. During the past decade, we have proposed that, besides peripheral immune dysregulation, opiates exacerbate the pathological effects of HIV in the CNS though direct actions on ¿-opioid receptor expressing (MOR) neurons and glia. The CNS may be preferentially vulnerable to opiate and HIV-1 interactions because of the complexity and interrelatedness of MOR action in neurons, astroglia, microglia and endothelium. We recently reported that convergent, neurotoxic effects of Tat or gp120 and morphine are largely due to actions of MOR+ glia. Our in vivo work supports a central role for glia in sublethal/lethal synaptodendritic injury. Morphine worsens structural and functional irregularities in hippocampus and striatum of Tat-expressing mice, including spine losses and synaptodendritic injury. Neurotoxic interactions with morphine and gp120 are HIV strain specific. Medium from monocytes exposed to live or UV-inactivated R5-tropic HIV-1SF162 virions is toxic to neurons; this is significantly attenuated by the CCR5 antagonist maraviroc. We hypothesize that opiate-induced exacerbation of HIV toxicity is regulated through differential CCR5 signaling between microglia, astroglia, and neurons, which can injure or protect neurons depending on context. We propose that opiates and Tat or HIV interact downstream of TNF¿ to enhance inflammatory chemokine release from astroglia. In particular, convergent effects of opiates and Tat/HIV appear to dysregulate CCL5/CCR5 signaling, creating a milieu that promotes microglial motility and spiraling microglial activation. Our hypotheses are tested in 3 aims that examine individual roles of astroglia and microglia in driving neurotoxic opiate-HIV interactions. Aims 1 & 2 use murine models for both: a) long-term, repeated imaging of cell death and sublethal neurodegenerative changes; and b) in vivo studies to detect population changes, neuron pathology, and behavioral deficits. Models include mice with cell-specific Cre-lox ablation of MOR, and inducible Tat transgenic mice crossed with CCL5-/- or CCR-/- mice. In Aim 3, human glia and neurons are used to study neurodegenerative changes due to HIV and opiate effects related to CCL5- CCR5 signaling in an infectious model with multiple strains of HIV. Infectious/non-infectious effects of CCR5 activation are sorted using live and inactivated virus, and mutant viral strains. The CCR5 pathway is especially relevant to HIV. CCR5 is an HIV co-receptor for M-tropic strains; CCR5 polymorphisms affect disease susceptibility; the CCR5 antagonist maraviroc slows HIV progression clinically. Studies are essential for informing therapeutic strategies. By defining how each glial type contributes to CCL5/CCR5 dysregulation, judicious cell- and pathway-specific measures to prevent the neurotoxic sequelae of opiate-HIV co-exposure can be designed.