Nonesterified Fatty Acids Cause Hepatic Ferroptosis in Dairy Cows via SIRT3-JNK Signaling

Elevated nonesterified fatty acid (NEFA) levels, resulting from excessive fat mobilization, are recognized as the pathological basis for fatty liver in dairy cows. Hepatotoxicity of high NEFA is antagonized by the activity of Sirtuin 3 (SIRT3). However, it is unclear whether SIRT3 antagonizes ferroptosis in bovine hepatocytes. Hence, we aimed to investigate the interplay between NEFA and SIRT3 on ferroptosis. High NEFA caused ferroptosis in cultured bovine hepatocytes, as validated by lipid peroxidation measurement, ultrastructure observation, and key gene expression. SIRT3 overexpression alleviated high NEFA-induced ferroptosis. RNA-seq revealed that NEFA-induced ferroptosis was inhibited by SIRT3 through the JNK signaling pathway, and this was further confirmed by the JNK signaling agonist assay. Dairy cows with fatty liver showed reduced hepatic SIRT3 protein levels alongside heightened JNK signaling activity. These results highlight the potential for targeting the SIRT3-JNK axis to prevent or alleviate NEFA-induced hepatotoxicity during the periparturient period.