Mito-TEMPO Ameliorates Sodium Palmitate Induced Ferroptosis in MIN6 Cells through PINK1/Parkin-Mediated Mitophagy.

Abstract

Objective: Mitochondrial reactive oxygen species (mtROS) could cause damage to pancreatic β-cells, rendering them susceptible to oxidative damage. Hence, investigating the potential of the mitochondria-targeted antioxidant (Mito-TEMPO) to protect pancreatic β-cells from ferroptosis by mitigating lipid peroxidation becomes crucial.

Methods: MIN6 cells were cultured in vitro with 100 μmol/L sodium palmitate (SP) to simulate diabetes. FerroOrange was utilized for the detection of Fe ²⁺ fluorescence staining, BODIPY581/591C11 for lipid reactive oxygen species, and MitoSox-Red for mtROS. Alterations in mitophagy levels were assessed through the co-localization of lysosomal and mitochondrial fluorescence. Western blotting was employed to quantify protein levels of Acsl4, GPX4, FSP1, FE, PINK1, Parkin, TOMM20, P62, and LC3. Subsequently, interventions were implemented using Mito-TEMPO and Carbonyl cyanide 3-chlorophenylhydrazone (CCCP) to observe changes in ferroptosis and mitophagy within MIN6 cells.

Results: We found that SP induced a dose-dependent increase in Fe ²⁺ and lipid ROS in MIN6 cells while decreasing the expression levels of GPX4 and FSP1 proteins. Through bioinformatics analysis, it has been uncovered that mitophagy assumes a crucial role within the ferroptosis pathway associated with diabetes. Additionally, SP decreased the expression of mitophagy-related proteins PINK1 and Parkin, leading to mtROS overproduction. Conversely, Mito-TEMPO effectively eliminated mtROS while activating the mitophagy pathways involving PINK1 and Parkin, thereby reducing the occurrence of ferroptosis in MIN6 cells. CCCP also demonstrated efficacy in reducing ferroptosis in MIN6 cells.

Conclusion: In summary, Mito-TEMPO proved effective in attenuating mtROS production and initiating mitophagy pathways mediated by PINK1 and Parkin in MIN6 cells. Consequently, this decreased iron overload and lipid peroxidation, ultimately safeguarding the cells from ferroptosis.