Molybdenum and cadmium co-induce mitophagy and mitochondrial dysfunction via ROS-mediated PINK1/Parkin pathway in Hepa1-6 cells

Excessive molybdenum (Mo) and Cadmium (Cd) can adversely affect health status. However, the correlation between mitophagy and mitochondrial dysfunction caused by Mo and Cd and the underlying mechanisms are still unknown. The aim of this study was to investigate the relationship between mitophagy and mitochondrial dysfunction via the ROS-mediated PINK1/Parkin pathway caused by Mo and Cd. Here, Hepa1–6 cells were incubated with (NH4)6Mo7O24.4 H2O (600.0 μM Mo), CdCl2 (10.0 μM Cd), and the combination of reactive oxygen species (ROS) scavenger (N-acetyl-L-cysteine, NAC, 100.0 μM), or mitophagy inhibitor (Cyclosporin A, CsA, 1.0 μM) for 24 h. Results revealed that Mo or/and Cd elevated the level of intracellular ROS and malondialdehyde (MDA) content, reduced superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) activities. Additionally, Mo or/and Cd could observably increase the percentage of cells with low membrane potential and decrease the content of ATP, elevate the number of autophagosomes and LC3 puncta, upregulate the mRNA and protein levels of LC3II/LC3I, Parkin, Pink1, VDAC1, downregulate mRNA and protein levels of P62. Moreover, treatments with NAC could significantly alleviate the changes of the above factors co-induced by Mo and Cd, and CsA intensify the changes of the above factors. In summary, our results reveal that Mo and Cd co-exposure can cause oxidative stress and mitophagy via the ROS-mediated PINK1/Parkin pathway in Hepa1–6 cells, and inhibition of mitophagy aggravates Mo and Cd co-induced mitochondrial dysfunction.