Inhibition of mitoNEET induces Pink1-Parkin-mediated mitophagy

Abstract

MitoNEET, a mitochondrial outer membrane protein containing the Asn-Glu-Glu-Thr (NEET) sequence, controls the formation of intermitochondrial junctions and confers autophagy resistance. Moreover, mitoNEET as a mitochondrial substrate undergoes ubiquitination by activated Parkin during the initiation of mitophagy. Therefore, mitoNEET is linked to the regulation of autophagy and mitophagy. Mitophagy is the selective removal of the damaged or unnecessary mitochondria, which is crucial to sustaining mitochondrial quality control. In numerous human diseases, the accumulation of damaged mitochondria by impaired mitophagy has been observed. However, the therapeutic strategy targeting of mitoNEET as a mitophagy-enhancing mediator requires further research. Herein, we confirmed that mitophagy is indeed activated by mitoNEET inhibition. CCCP (carbonyl cyanide m-chlorophenyl hydrazone), which leads to mitochondrial depolarization, induces mitochondrial dysfunction and superoxide production. This, in turn, contributes to the induction of mitophagy; mitoNEET protein levels were initially increased before an increase in LC3-Ⅱ protein following CCCP treatment. Pharmacological inhibition of mitoNEET using mitoNEET Ligand-1 (NL-1) promoted accumulation of Pink1 and Parkin, which are mitophagy-associated proteins, and activation of mitochondria–lysosome crosstalk, in comparison to CCCP alone. Inhibition of mitoNEET using NL-1, or mitoNEET shRNA transfected into RAW264.7 cells, abrogated CCCP-induced ROS and mitochondrial cell death; additionally, it activated the expression of PGC-1α and SOD2, regulators of oxidative metabolism. In particular, the increase in PGC-1α, which is a major regulator of mitochondrial biogenesis, promotes mitochondrial quality control. These results indicated that mitoNEET is a potential therapeutic target in numerous human diseases to enhance mitophagy and protect cells by maintaining a network of healthy mitochondria.

Mitochondrial CISD1/Cisd accumulation blocks mitophagy and genetic or pharmacological inhibition rescues neurodegenerative phenotypes in Pink1/parkin models

“…We have shown that depletion of CISD proteins increased mitophagy in vivo and in human cells. A recent report has also described that genetic or pharmacologic inhibition of CISD1 upregulated Parkin-dependent mitophagy in human cells [55], although our data indicate that Cisd depletion-induced mitophagy can be Parkin-independent since it occurred in parkin mutant ies. Interestingly, while we found that Cisd depletion-induced mitophagy alleviated blocked mitochondrial turnover in Pink1/parkin mutants, under steady-state conditions mitophagy induction occurred in quite selective circumstances, notably in aged muscle.…”

PINK1/Parkin‐mediated mitophagy enhances the survival of Staphylococcus aureus in bovine macrophages

“…Mdivi‐1, an inhibitor of Drp1, was reported in studies to block mitochondrial fission. CCCP and Mdivi‐1 have been reported in several studies as regulators of mitophagy 25,26,28 . Next, we focused on the relationship between mitochondria and intracellular parasitism of S. aureus .…”

“…CCCP and Mdivi‐1 have been reported in several studies as regulators of mitophagy. 25 , 26 , 28 Next, we focused on the relationship between mitochondria and intracellular parasitism of S. aureus . CCCP and Mdivi‐1 were used to regulate mitochondrial autophagy.…”

Iron-sulfur cluster loss in mitochondrial CISD1 mediates PINK1 loss-of-function phenotypes

“…NL-1 has shown promise in mouse models of traumatic brain injury (Yonutas et al , 2020), ischemic stroke (Saralkar et al , 2021), and lipopolysaccharide-induced inflammation (Lee et al , 2022b). It was even shown to induce mitophagy by promoting accumulation of PINK1 and Parkin (Lee et al , 2022a). Future studies will further explore the potential of NL-1 to mitigate the progression of Parkinson’s disease in animal models and potentially in patients.…”