Morphine disrupts the regulation of neuronal function mediated by astrocyte exosomes

 描述(申请人提供)：在抗逆转录病毒治疗(ART)的时代，神经元连接的减少、突触简化和树突复杂性的减少与艾滋病毒感染者认知障碍的严重程度相关。也有相当多的证据表明，使用阿片类药物的艾滋病毒感染者的突触损伤和认知障碍更严重。虽然许多研究表明，吗啡与艾滋病毒及其组成部分相互作用，导致星形胶质细胞和神经元生物学失调，但这些相互作用的机制尚不清楚。星形胶质细胞和神经元之间的双向通讯调节突触的形成和突触强度，并通过协调神经元之间的活动参与神经回路的调节。细胞外小泡生物学的最新进展已经开始涉及到神经胶质释放的微粒作为神经胶质细胞与神经元通讯的媒介。在初步实验中，我们发现星形胶质细胞外切体(在内源性刺激下释放)在施加到神经元上时调节神经营养反应。我们确定外切体的分子货物是复杂的，包含约280种不同的蛋白质、114种miRNA和数百种脂类。此外，星形胶质细胞外切体的分子组成被用来诱导释放的刺激所改变。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的关注不太可能产生这些重要信号复合体的真实功能代表。因此，我们使用生物信息学的方法来了解外切体的整个组成如何与神经元信号通路相互作用，并将我们的努力集中在少数已识别的通路上。特别是，我们集中在与突触形成、脊柱形成和轴突生长相关的神经通路上，因为这些通路与对内源性刺激释放的星形胶质细胞外体的神经营养反应是一致的。这项应用的目标是了解HIV和吗啡如何调节星形胶质细胞外切体的货物，以及这些货物的差异如何调节神经元中的树突和突触功能。

 DESCRIPTION (provided by applicant): In the era of Antiretroviral Therapy (ART), reductions in neuronal connectivity, synaptic simplification and reductions in dendritic complexity are correlated with the severity of cognitive impairments in HIV-infected individuals. There is also considerable evidence that synaptic damage, and cognitive impairments are worse in HIV-infected people who use opiate drugs. Although a number of studies have shown that morphine interacts with HIV and components of HIV to dysregulate astrocyte and neuronal biology, the mechanisms for these interactions are not understood. 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. Recent advancements in the biology of extracellular vesicles have begun to implicate glial released microparticles as mediators of glia to neuron communication. In preliminary experiments we found that astrocyte exosomes (released in response to a endogenous stimuli) regulated a neurotrophic response when applied onto neurons. We determined that the molecular cargo of exosomes is complex and contains ~280 distinct proteins, 114 miRNA, and hundreds of lipid species. Moreover, the molecular composition of astrocyte exosomes was modified by the stimulus used to induce release. 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 function for these important signaling complexes. Therefore, we used bioinformatics approaches to understand how the entire composition of exosomes interacts with neuronal signaling pathways, and 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 pathways were consistent with the neurotrophic response to astrocyte exosomes released in response to an endogenous stimuli. The goals of this application are to understand how HIV and morphine modulate the cargo of astrocyte exosomes and how these differences in cargo regulate dendritic and synaptic functions in neurons.