Cocaine upregulates mitochondria-derived vesicular pathway for selective removal of oxidized cargo

线粒体是动态细胞器，在细胞新陈代谢中起着核心作用。我们的预赛 数据显示，当星形胶质细胞暴露在可卡因中时，会增加OXPHOS活性，导致产生 线粒体活性氧(MRO)。相反，增加的MRO代并不是 伴有线粒体去极化、有丝分裂或细胞死亡。基于这些观察，我们 假设氧化的线粒体蛋白复合体稳定去除的另一种机制 促进星形胶质细胞的激活、增殖和存活，并可能扰乱神经元-胶质细胞信号转导，从而 在滥用可卡因期间导致中枢神经系统突触受损。目前的提案 将侧重于确定负责可卡因诱导变化的星形胶质细胞中的线粒体质量控制机制。线粒体质量控制是清除线粒体堆积所需的必要过程 细胞器中未折叠、氧化或以其他方式损坏的蛋白质和脂类。作为“能源强国”， 线粒体依赖于几种不同的路径，这些路径不断地检测损伤。除了包括结构性线粒体蛋白分解和有丝分裂在内的描述良好的途径外，最近的研究 发现了一种新的线粒体质量控制途径，不受细菌的影响，在这种途径中，线粒体 释放线粒体衍生的小泡(MDV)。在这种情况下，我们观察到MDV在 暴露于可卡因的星形胶质细胞，提示MDV的形成是一种基本的管家机制和一种 对抗可卡因诱导的星形胶质细胞毒性的第一道防线。我们的高风险/高回报方法是：(I) 在稳态下观察编队MDV，(Ii)分析货物选择性，(Iii)表征不同的MDV 以及(Iv)确定最终的递送目的地(即，运输到溶酶体或过氧化物体) 可卡因的存在。我们的长期目标是了解MDV如何构成数量和高度 可卡因使用过程中线粒体质量控制的选择性途径为未来提供平台 研究和干预。

Mitochondria are dynamic organelles that have a central role in cellular metabolism. Our preliminary data show that astrocytes, when exposed to cocaine, increase the OXPHOS activity leading to generation of mitochondrial reactive oxygen species (mROS). Conversely, the increased generation of mROS was not accompanied by mitochondrial depolarization, mitophagy or cell death. Based on these observations, we hypothesize that another mechanism of steady-state removal of oxidized mitochondrial protein complexes facilitated astrocytic activation, proliferation and survival and may disrupt the neuron-glia signaling, thereby contributing to synaptic impairment in the central nervous system during cocaine abuse. The current proposal will focus on identifying the mitochondrial quality control mechanism in astrocytes responsible for cocaine-induced changes. Mitochondrial quality control is an essential process required to clear the accumulation of unfolded, oxidized or otherwise damaged proteins and lipids from the organelle. As the “energy powerhouse”, mitochondria depend on several different pathways that continually survey for damage. Apart from the well-characterized pathways including constitutive mitochondrial proteolysis and mitophagy, recent studies uncovered a novel mitochondrial quality control pathway, conserved from bacteria, in which mitochondria release small, mitochondrial-derived vesicles (MDVs). In this context, we observed rapid formation of MDVs in astrocytes exposed to cocaine, suggesting MDV formation as an essential housekeeping mechanism and a first line of defense against cocaine-induced toxicity in astrocytes. Our high risk/high reward approach is (i) to observe the formation MDVs in steady state, (ii) analyze the cargo selectivity, (iii) characterize distinct MDV pools, and (iv) identify the final delivery destination (ie., transport to lysosomes or peroxisomes) in the presence of cocaine. Our long-term goal is to understand how MDVs comprise a quantitative and highly selective pathway utilized for mitochondrial quality control during cocaine use to provide a platform for future research and intervention.