Development and characterization of an AAV-based tool to functionally ablate astrocytic mitochondria in specific brain regions in vivo

项目摘要 星形胶质细胞是一组在大脑中具有多种作用的神经胶质细胞。它们扩展了精细的流程， 定位于突触和血管附近，从而局部调节突触的形成、消除和 功能，以及血脑屏障通透性。这一地方性法规对功能的影响更广泛 大脑中更大的神经回路。不同脑区的星形胶质细胞表现出不同的形态和 基因表达谱，表明功能的区域特异性。神经元退行性变， 脑部疾病，如帕金森氏病(PD)和阿尔茨海默病(AD)，以及星形细胞增多症 故障被怀疑，但在机械上没有得到很好的描述。 星形胶质细胞中的线粒体最近作为特殊的亚细胞细胞器出现，具有强大的 一种独特的功能蛋白质组--能够对神经递质激动剂做出反应的自发钙离子通量 与钙通量和形态的过程相比，体细胞的空间分离。 这些独特的特征使我们假设，星形细胞线粒体的异常在 在加速大脑中的神经退化过程中的作用。然而，缺乏功能性消融的工具 体内特定脑区星形胶质细胞中的线粒体是决定 星形胶质细胞线粒体功能障碍如何导致神经变性。具体地说，开发这样一个工具 将有助于从机制上理解星形细胞线粒体在帕金森病和阿尔茨海默病中的作用。在这里，我们 建议开发和鉴定一种基于腺相关病毒(AAV)的功能性消融工具 与PD和AD相关的两个脑区的星形细胞线粒体。纹状体和后扣带 分别为大脑皮层。此外，我们还将研究细胞自主和非细胞自主的影响 功能性消融星形胶质细胞线粒体对星形胶质细胞和神经元基因表达谱的影响及未来 目的是将所获得的知识应用于帕金森病和阿尔茨海默病的体内模型。

PROJECT ABSTRACT Astrocytes are a group of glial cells with multiple roles in the brain. They extend fine processes that localize near synapses and blood vessels and thus locally regulate synapse formation, elimination and function, as well as blood-brain-barrier permeability. This local regulation more broadly impacts on the function of larger neural circuits within the brain. Astrocytes from different brain regions show distinct morphological and gene expression profiles, which suggest regional specificity of function. Links between neuronal degeneration, distinctive of brain maladies such as Parkinson’s disease (PD) and Alzheimer’s disease (AD), and astrocytic malfunction are suspected but not well characterized mechanistically. Mitochondria in astrocytes have recently emerged as specialized subcellular organelles with robust spontaneous Ca2+ fluxes capable of responding to neurotransmitter agonists, a distinct functional proteomic profile, and spatial segregation into somata versus processes with regard to Ca2+ fluxes and morphology. These unique characteristics lead us to hypothesize that abnormalities in astrocytic mitochondria play a major role in accelerating neurodegenerative processes in the brain. However, the lack of tools to functionally ablate mitochondria selectively in astrocytes from specified brain regions in vivo is a major barrier towards defining how astrocytic mitochondrial dysfunction contributes to neurodegeneration. Specifically, developing such a tool would enable a mechanistic understanding of the role of astrocytic mitochondria in PD and AD. Here, we propose to develop and characterize an adeno-associated virus (AAV)-based tool to functionally ablate astrocytic mitochondria in two brain regions relevant to PD and AD, viz. the striatum and posterior cingulate cortex, respectively. In addition, we will examine the cell-autonomous and non-cell autonomous effects of functionally ablating astrocytic mitochondria on astrocytic and neuronal gene expression profiles with the future goal of applying the knowledge gained to in vivo models of PD and AD.