Coenzyme Q10 alleviates the mitochondrial damage by high-fat load in hepatocytes of spotted seabass (Lateolabrax maculatus) via promoting mitophagy

Coenzyme Q10, as a natural fat-soluble compound, can play a role in protecting mitochondria, but the mechanism is still unclear. Here, we explored the mechanism of coenzyme Q10 enhancing mitochondrial function using hepatocytes of spotted seabass. Three groups were set: normal medium as control group, fatty acid group containing 100 mol/L FA (FA group), and 100 mol/L FA and 5 mol/L coenzyme Q10 group (FA+COQ10). After the culture, the results showed that FA treatment significantly increased the triglyceride content in the cells. Bodipy staining showed that many lipid droplets appeared in the FA group, while coenzyme Q10 reduced triglycerides content and lipid droplets. Moreover, coenzyme Q10 significantly reduced the content of ROS in cells. After scavenging ROS, the liver cell damage caused by FA was alleviated, the mitochondrial membrane potential and its mitochondrial metabolic enzyme activity were restored, and the ATP content was increased. Further analysis showed that FA significantly down-regulated the expression of mitophagy key genes pink, parkin and lc3b, while up-regulated the expression of p62. Through mitochondrial fluorescence staining and mtDNA content detection, it was found that the number of mitochondria in FA-treated cells decreased significantly, while the number of mitochondria increased significantly after FA+COQ10 treatment. This indicates that coenzyme Q10 can significantly promote the mitophagy process. In order to further study whether the enhancement of mitochondrial function by coenzyme Q10 is related to the activation of autophagy, we set up FA group, FA+COQ10 group and FA+COQ10+Mdivi-1 group (pretreatment with mitophagy inhibitor Mdivi-1). After Mtphagy Dye staining, it was found that the number of autophagosomes in the FA+COQ10+Mdivi-1 group was lower than that in the FA+COQ10 group, indicating that the activation of mitophagy by coenzyme Q10 was inhibited. The results of this study indicate that coenzyme Q10 enhances mitochondrial function and alleviates excessive fat deposition dependent on PINK1-mediated mitophagy.