Cr(VI)-induced overactive mitophagy contributes to mitochondrial loss and cytotoxicity in L02 hepatocytes

Hexavalent chromium [Cr(VI)] has aroused the main interest of environmental health researchers due to its high toxicity. Liver is the main target organ of Cr(VI), and the purpose of this study was to explore whether mitophagy contributes to Cr(VI)-induced hepatotoxicity and to demonstrate the potential mechanisms. Cr(VI) exposure induced mitochondrial loss, energy metabolism disorders and cell apoptosis, which were associated with the occurrence of excessive mitophagy characterized by the increased number of green fluorescent protein-microtubule-associated protein light chain 3 (GFP-LC3) puncta and lysosomal colocalization with mitochondria. In addition, the suppression of mitophagy by autophagy-related 5 (ATG5) siRNA can effectively inhibit Cr(VI)-induced mitochondrial loss and cytotoxicity. In summary, we reached the conclusion that Cr(VI)-induced overactive mitophagy contributes to mitochondrial loss and cytotoxicity in L02 hepatocytes, which will further reveal the possible mechanisms of Cr(VI)-induced hepatotoxicity, and provide a new experimental basis for the study of the health hazard effects of chromium.