Induction of autophagy via the ROS-dependent AMPK/mTOR pathway protects deoxynivalenol exposure grass carp hepatocytes damage

Abstract

Deoxynivalenol (DON) is one of the most frequently found mycotoxin sources in feed and raw food products, endangering human and animal health. The mechanism of grass carp (Ctenopharyngodon idellus) liver cell (L8824) toxicity induced by DON is still unknown. The DON was administered to the L8824 cells in concentrations of 150, 200, and 250 ng/mL for 24 h. The results of this study suggested that DON could enable L8824 cells to significantly increase the levels of autophagy. Concurrently, DON could trigger autophagy through the AMPK-mTOR pathway, which upregulated the expression of p-AMPK and p-ULK1 while downregulating the expression of p-mTOR. In the meantime, DON treatment could alter the levels of expression of the related proteins in autophagy. Additionally, DON treatment dramatically reduced the activity of the antioxidant enzymes as well as increased the levels of oxidase, which increased the production of ROS in L8824 cells. This indicates that DON could induce oxidative stress. Furthermore, we discovered that DON exposure caused apoptosis, which is characterized by elevated levels of BAX, Caspase 9, Caspase 3, and decreased Bcl-2 levels. Next, it was investigated how oxidative stress affected DON-induced autophagy. The research revealed that the oxidative stress inhibitor (NAC) attenuated DON-induced autophagy. Additionally, the study also investigated how autophagy worked under the L8824 cells induced by DON. The ROS production, however, was enhanced by the addition of the autophagy inhibitor (3-MA). Additionally, co-treatment with the apoptosis inhibitor Z-VAD-FMK had no influence on autophagy. The combined findings showed that induction of autophagy via the ROS-dependent AMPK-mTOR pathway protects DON-induced L8824 cells from damage.