Superoxide drives progression of Parkin/PINK1-dependent mitophagy following translocation of Parkin to mitochondria

Abstract

Reactive oxygen species (ROS) and mitophagy are profoundly implicated in the pathogenesis of neurodegenerative diseases, such as Parkinson’s disease (PD). Several studies have suggested that ROS are not involved in mitochondrial translocation of Parkin which primes mitochondria for autophagic elimination. However, whether ROS play a role in the execution of mitophagy is unknown. In the present study, we show that carbonyl cyanide m-chlorophenylhydrazone (CCCP) treatment induced both mitochondrial depolarization and generation of ROS that were needed for the mitophagy process. Cells failed to proceed to complete mitophagy if CCCP treatment was discontinued even after recruitment of Parkin and autophagy machinery to mitochondria. Notably, treatment of pro-oxidant was able to replace CCCP treatment to take mitophagy forward, while it alone was insufficient to induce translocation of Parkin to mitochondria or autophagic clearance of mitochondria. In addition, an SOD mimetic that attenuated the superoxide level suppressed mitophagy, while an SOD inhibitor accumulated cellular superoxide and promoted mitophagy. Furthermore, blockage of the p38 signaling pathway inhibited mitophagy induced by ROS, suggesting that it may contribute to the activation of ROS-mediated mitophagy. Together, our study sheds light on the link between ROS and mitophagy at a molecular level, and suggests the therapeutic potential of regulating mitophagy through the superoxide–p38–mitophagy axis.

The Role of Reactive Oxygen Species in the Life Cycle of the Mitochondrion

“…However, the treatment of pro-oxidant alone was insufficient to induce translocation of Parkin to mitochondria or autophagic clearance of mitochondria. Moreover, it was also shown that the p38 signaling pathway may contribute to the progression of mitophagy induced by ROS [281]. This result agrees with those of previous authors reporting that the MAPK signaling pathway was required for mitophagy in Saccharomyces cerevisiae [282] and HeLa cells [283].…”

Cholesterol Alters Mitophagy by Impairing Optineurin Recruitment and Lysosomal Clearance in Alzheimer’s Disease

“…In these cells, pretreatment with GSHee, a membrane-permeable derivative of GSH that recovers the mitochondrial GSH content and inhibits A -induced ROS [18,26], completely abolished the presence of mitochondrial PINK1 and mitophagosomes formation. These data complement previous studies that illustrate how modulation of the mitochondrial antioxidant protein superoxide dismutase-2 has a direct impact on mitophagy progression, and point to mitochondrial ROS production as an upstream inducer of the process [61,66,67].…”

Autophagy, Cellular Aging and Age-related Human Diseases

“…Cells with reduced AMPK activity increase mitochondrial ROS and experience premature aging [49]. Parkinsonism-causing genes like Parkin, phosphatase and tensin homolog-induced putative kinase (PINK), and DJ-1 impact mitochondrial health via autophagy [50][51][52]. ROS promotes Parkin/PINK-dependent mitophagy [50].…”

“…Parkinsonism-causing genes like Parkin, phosphatase and tensin homolog-induced putative kinase (PINK), and DJ-1 impact mitochondrial health via autophagy [50][51][52]. ROS promotes Parkin/PINK-dependent mitophagy [50]. Also, Parkin induces beclin1-mediated autophagic degradation of molecular debris and dysfunctional mitochondria, which prevents oxidative stress [51].…”