Mitochondrial reactive oxygen species modify extracellular vesicles secretion rate

Abstract

Extracellular vesicle (EV) secretion rate is stimulated by hypoxia that causes increased reactive oxygen species (ROS) production by the mitochondrial electron transport chain (ETC) and hypoxia‐induced factor (HIF)‐1 signaling; however, their contribution to the increased EV secretion rate is unknown. We found that the EV marker secretion rate in our EV reporter cell line CD9truc‐EGFP was unaffected by the HIF‐1α stabilizer roxadustat; yet, ETC stimulation by dichloroacetic acid (DCA) significantly increased EV secretion. The DCA‐induced EV secretion was blocked by the antioxidant TEMPO and rotenone, an inhibitor of the ETC's Complex I. Under hypoxic conditions, the limited oxygen reduction impedes the ETC's Complex III. To mimic this, we inhibited Complex III with antimycin A, which increased ROS‐dependent EV secretion. The electron transport between Complex I and III is accomplished by coenzyme Q created by the mevalonate pathway and tyrosine metabolites. Blocking an early step in the mevalonate pathway using pitavastatin augmented the DCA‐induced EV secretion, and 4‐nitrobenzoate—an inhibitor of the condensation of the mevalonate pathway with tyrosine metabolites—increased ROS‐dependent EV secretion. Our findings indicate that hypoxia‐mimetics targeting the ETC modify EV secretion and that ROS produced by the ETC is a potent stimulus for EV secretion.

Cholesterol Metabolite 27-Hydroxycholesterol Enhances the Secretion of Cancer Promoting Extracellular Vesicles by a Mitochondrial ROS-Induced Impairment of Lysosomal Function

“…Several studies have shown that elevated levels of reactive oxygen species (ROS) result in impaired lysosomal function (51,52). Interestingly, elevated ROS has also been found to increase EV secretion (53,54).…”

Alcohol and e-cigarette damage alveolar-epithelial barrier by activation of P2X7r and provoke brain endothelial injury via extracellular vesicles

“…UPR stimulated by alcohol and other abusive drugs facilitates ER stress, followed by ER-Ca 2+ efflux into the mitochondrial matrix, resulting in mitochondrial OXPHOS reduction and ROS accumulation [ 36 , 37 ]. Mitochondrial dysfunction and ROS buildup promote EV release in mouse myeloblast cells [ 38 ]. Similarly, morphine-exposed BMVECs revealed redox imbalance, resulting in unwarranted EV release [ 39 ].…”

New guidelines to uncover the physiology of extracellular vesicles

“…For example, conditions that increase mitochondria-derived reactive oxygen species production, such as hypoxia, are associated with higher EV secretion rates. 8 This adds extra challenges to the physiological interpretation of EV data; the RNA and protein levels measured in isolated EVs are the product of two dynamically regulated parameters: the cargo level within each EV and the EV abundance. The dynamic cell type-specific EV secretion rate, thus, confounds EV data analyses.…”

“…In addition to biodistribution and clearance of EVs, cell type‐specific EV secretion rates span several orders of magnitude, 4 and in vitro studies of cultured cells have demonstrated that EV secretion rates are not constant. For example, conditions that increase mitochondria‐derived reactive oxygen species production, such as hypoxia, are associated with higher EV secretion rates 8 . This adds extra challenges to the physiological interpretation of EV data; the RNA and protein levels measured in isolated EVs are the product of two dynamically regulated parameters: the cargo level within each EV and the EV abundance.…”