Dysregualtion of gliotransmission in models of neuroHIV

 描述（由申请人提供）：星形胶质细胞和神经元之间的双向通信调节突触形成、突触强度，并通过协调神经元组之间的活动参与神经回路的调节。在HIV感染和其他神经退行性疾病的背景下，星形胶质细胞功能障碍被认为会破坏参与记忆和执行功能的神经网络的活动。虽然已经证明了从星形胶质细胞释放的各种细胞因子、趋化因子和生长因子的组成和数量的HIV相关扰动，但这些观察结果迄今仍不足以解释星形胶质细胞应激如何导致神经元功能障碍。这些问题在抗逆转录病毒疗法（ART）时代尤其重要，其中神经元连接的减少、突触简化和树突复杂性的减少被认为是HIV感染个体中认知障碍的主要贡献者。我们对细胞外囊泡生物学的理解的进步已经开始暗示胶质细胞释放的微囊泡是胶质细胞与神经元通讯的主要介质。在初步实验中，我们提供的证据表明，各种刺激可以诱导星形胶质细胞脱落微泡。星形胶质细胞脱落微泡的分子货物是复杂的，包含200多种不同的蛋白质，100种miRNA和数百种生物活性脂质物质。此外，星形胶质细胞外泌体的蛋白质、miRNA和脂质组成被用于诱导释放的刺激物修饰。这些星形胶质细胞脱落的外泌体直接与神经元相互作用，以改变神经元的结构和功能。基于这些初步发现，我们推断，科学上对任何一种蛋白质、脂质或miRNA的关注都不太可能真实地代表这种复杂的信号囊泡所调控的功能。因此，我们使用生物信息学和系统生物学方法来了解外泌体的蛋白质、miRNA和脂质组成如何相互作用以调节通过靶神经元的全基因组测序鉴定的神经元信号传导途径。在本申请中，我们将精力集中在少数已确定的途径上。特别是，我们集中在与突触形成，棘形成和神经突生长相关的神经通路，因为这些神经元结构似乎在许多HIV感染者中受损。本申请的目标是了解与HIV感染相关的内源性兴奋性刺激和炎症刺激如何调节星形胶质细胞脱落的外泌体的货物，以及这些外泌体如何调节/失调其靶神经元的结构和功能。

 DESCRIPTION (provided by applicant): Bi-directional communication between astrocytes and neurons regulates synaptic formation, synaptic strength, and participates in the regulation of neural circuitry by coordinating activity among groups of neurons. Astrocyte dysfunction in the settings of HIV-infection, and other neurodegenerative conditions has been postulated to disrupt the activity of neural networks involved in memory and executive functions. Although HIV-associated perturbations in the composition and quantity of various cytokine, chemokine and growth factors released from astrocytes have been demonstrated, these observations have thus far been insufficient to explain how astrocyte stress contributes to neuronal dysfunction. These questions are particularly important in the era of Antiretroviral Therapy (ART), where reductions in neuronal connectivity, synaptic simplification and reductions in dendritic complexity are thought to be primary contributors to cognitive impairments in HIV- infected individuals. Advancements in our understanding of the biology of extracellular vesicles have begun to implicate glial released microvesicles as primary mediators of glia to neuron communication. In preliminary experiments we provide evidence that a variety of stimuli can induce astrocytes to shed microvesicles. The molecular cargo of astrocyte-shed microvesicles was complex and contained more than 200 distinct proteins, 100 miRNA, and hundreds of bioreactive lipid species. Moreover, the protein, miRNA and lipid composition of astrocyte exosomes was modified by the stimulus used to induce release. These astrocyte-shed exosomes directly interacted with neurons to modify neuronal structure and function. Based on these preliminary findings we reasoned that a scientific focus on any one protein, lipid or miRNA would be unlikely to produce a true representation of the functions regulated by this complex signaling vesicles. Therefore, we used bioinformatic and systems biology approaches to understand how the protein, miRNA and lipid composition of exosomes interacts to regulate neuronal signaling pathways identified by whole genome sequencing of target neurons. In this application we focused our efforts on a small number of the identified pathways. In particular we concentrated on neural pathways associated with synapse formation, spine formation, and neurite outgrowth, as these neuronal structures appear to be damaged in many HIV infected individuals. The goals of this application are to understand how endogenous excitatory stimuli and inflammatory stimuli associated with HIV-infection modulate the cargo of astrocyte-shed exosomes and how these exosomes regulate/dysregulate the structure and function of their target neurons.