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

线粒体是在细胞代谢中起中心作用的动态细胞器。我们的初步

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.