A DUAL CHIMERIC HUMAN ASTROGLIAL-MICROGLIAL MODEL OF HIV AND HAND

摘要突触功能障碍是HIV感染的重要特征，也是HIV感染的一个可能的关键因素。 相关的神经认知障碍（HAND）。然而，目前的动物模型已被证明在定义 这一过程的机制，部分是因为艾滋病毒感染的物种特异性，但也因为 人类星形胶质细胞的复杂性比老鼠的更高。为了解决这个问题，我们将利用老鼠 嵌合的人小胶质细胞和人星形胶质细胞，以评估HIV感染对中枢神经系统的影响。 神经元为此，我们将人类神经胶质祖细胞（hGPCs）和小胶质细胞移植到小鼠体内， 来源于胚胎干细胞（hESC）。我们已经建立了产生这些人类神经胶质细胞的方法， 嵌合体，通过hGPCs的新生儿植入，其胜过并最终取代宿主小鼠 GPCs，产生广泛定植有人类星形胶质细胞的成年嵌合体1 -5。这一过程尤其适用于 新纹状体，允许关键参与纹状体奖励和成瘾回路的区域的神经胶质人源化。 我们最近扩展了这种方法，包括与hESC衍生的小胶质细胞嵌合，与 使用缺乏宿主小胶质细胞的CSF 1 R敲除小鼠，与NSG SGM 3小鼠杂交，以允许稳定的异种移植 hGPCs因此，小鼠在T和B细胞缺陷型中嵌合hGPC衍生的星形胶质细胞以及小胶质细胞。 背景允许神经胶质HIV感染对神经元的影响被分离，脑内注射后， 接种艾滋病毒感染的小胶质细胞。这些嵌合的人星形胶质细胞-小胶质细胞（CHAM）小鼠尤其是 吸引人，因为它们结合了人类星形胶质细胞的原始人特有的特征，这本身就是关键 中央突触的组成部分。使用这个模型，我们将测试星形胶质细胞既成为 小胶质细胞HIV感染在结构和功能上受损，导致突触接合丧失， 受影响的星形胶质细胞，随之而来的树突退化和网络中断。通过感染CHAM小鼠， 我们将利用狂犬病病毒-EGFP追踪纹状体树突，评估星形胶质细胞HIV感染的影响 树突状结构和突触结构的居民中型多刺神经元。同时，我们将研究 CHAM小鼠中HIV感染并发甲基苯丙胺使用的影响-一种常见的和致残的 抑制多巴胺能输入纹状体的共代谢物-关注结构和转录 人类神经胶质细胞对感染和成瘾的反应，以及对行为的影响。 这种组合。为此，我们将使用单细胞RNA-Seq来评估基因表达的变化， 人类星形胶质细胞和它们的伴侣小鼠神经元引起的HIV感染，无论是单独和一起， 慢性甲基苯丙胺的使用，以确定这些变化，有助于纹状体突触破坏， 这些小鼠的行为病理学。我们的目标是检验这样一个假设，即艾滋病毒感染的纹状体， 特别是星形胶质细胞纤维与多巴胺能突触的分离， 安非他明滥用，同时定义神经胶质病理学的转录基础，这种脆弱性。

Abstract Synaptic failure is an important feature of HIV infection of the brain, and a likely key contributor to HIV- associated neurocognitive disorders (HAND). Yet current animal models have proven of limited utility in defining the mechanisms of this process, in part because of the species-specific nature of HIV infection, but also because of the greater complexity of human astrocytes relative to those of mice. To address this issue, we will utilize mice chimeric for both human microglia and human astrocytes, to assess the effects of HIV infection on central neurons. To that end, we will engraft mice with both human glial progenitor cells (hGPCs) and microglia, each derived from embryonic stem cells (hESCs). We have established the methods of generating these human glial chimeras, by the neonatal implantation of hGPCs, which outcompete and ultimately replace the host mouse GPCs, yielding adult chimeras broadly colonized with human astroglia1-5. This process is especially robust in the neostriatum, allowing the glial humanization of regions critically involved in striatal reward and addiction circuits. We have recently extended this approach to include chimerization with hESC-derived microglia, paired with the use of CSF1R null mice lacking host microglia, crossed to NSG SGM3 mice to allow the stable xenograft of hGPCs. The mice are thus chimeric for hGPC-derived astrocytes as well as microglia, in a T- and B-cell deficient background that allows the effects of glial HIV infection on neurons to be isolated, following intracerebral inoculation with HIV-infected microglia. These chimeric human astroglial-microglial (CHAM) mice are especially attractive, since they incorporate the hominid-specific features of human astroglia, which are themselves key components of central synapses. Using this model, we will test the postulate that astrocytes become both structurally and functionally impaired by microglial HIV infection, resulting in the loss of synaptic engagement by affected astrocytes, with consequent dendritic involution and network disruption. By infecting CHAM mice with HIV, and using rabies viral-EGFP to trace striatal dendrites, we will assess the effects of astrocytic HIV infection on the dendritic architecture and synaptic structure of resident medium spiny neurons. In parallel, we will study the effects in CHAM mice of HIV infection complicated by methamphetamine use – a common and disabling comorbidity that suppresses dopaminergic input to the striatum – focusing on the structural and transcriptional responses of human glia to the combination of infection and addiction, as well as on the behavioral effects of that combination. To that end, we will use single cell RNA-Seq to assess the changes in gene expression by human astrocytes and their partnered mouse neurons caused by HIV infection, both alone and together with chronic methamphetamine use, to identify those changes that contribute to the striatal synaptic disruption and behavioral pathology of these mice. Our goal is to test the hypothesis that the HIV-infected striatum, by virtue of astrocytic fiber disengagement from dopaminergic synapses in particular, is especially vulnerable to the effects of amphetamine abuse, while defining the transcriptional basis for the glial pathology underlying that vulnerability.