Glial origins of HIV and opiate-driven synaptodendritic injury

说明（由申请人提供）：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易换取毒品而进一步传播。在过去的十年中，我们提出，除了外周免疫失调，阿片类药物通过直接作用于阿片受体表达（MOR）神经元和胶质细胞，加剧了艾滋病毒在中枢神经系统中的病理作用。由于神经元、星形胶质细胞、小胶质细胞和内皮细胞中MOR作用的复杂性和相互关联性，中枢神经系统可能优先易受阿片和HIV-1相互作用的影响。我们最近报道了Tat或gp120和吗啡的收敛性神经毒性作用主要是由于MOR+胶质细胞的作用。我们的体内研究支持了胶质细胞在亚致死性/致死性突触树突损伤中的核心作用。吗啡加重了表达tat的小鼠海马和纹状体的结构和功能紊乱，包括脊柱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毒株特异性的。暴露于活的或紫外线灭活的R5-tropic HIV-1SF162病毒粒子的单核细胞培养基对神经元有毒性；CCR5拮抗剂maraviroc可显著减轻这一症状。我们假设阿片类药物引起的HIV毒性恶化是通过小胶质细胞、星形胶质细胞和神经元之间的CCR5信号传导调节的，这可以根据环境损伤或保护神经元。我们提出阿片类药物和Tat或HIV在TNF -下游相互作用，以增强星形胶质细胞的炎症趋化因子释放。特别是，阿片类药物和Tat/HIV的趋同效应似乎失调了CCL5/CCR5信号，创造了一个促进小胶质细胞运动和螺旋状小胶质细胞激活的环境。我们的假设在三个目标中得到验证，这些目标检验了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相互作用中的个体作用。目的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)体内研究，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，以及诱导Tat转基因小鼠与CCL5-/-或CCR-/-小鼠杂交。在Aim 3中，人类神经胶质细胞和神经元被用于研究HIV引起的神经退行性改变，以及在多株HIV感染模型中与CCL5- CCR5信号相关的鸦片效应。CCR5激活的传染性/非传染性效应使用活病毒和灭活病毒以及突变病毒株进行分类。CCR5通路与HIV尤其相关。CCR5是嗜m型毒株的HIV共受体；CCR5多态性影响疾病易感性；CCR5拮抗剂马拉维洛克在临床上减缓HIV的进展。研究对制定治疗策略至关重要。通过确定每种胶质细胞类型如何导致CCL5/CCR5失调，可以设计出明智的细胞和途径特异性措施来预防阿片类药物- hiv共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.