Monocrotaline induces liver injury via TRX1-ASK1-JNK Axis-mediated mitochondrial damage in hepatocytes

Pyrrolizidine alkaloid-induced liver injury (PAs-ILI) is a significant hepatic disorder resulting from exposure to pyrrolizidine alkaloids (PAs), often presenting as acute liver damage that may progress to cirrhosis, liver failure, or death; however, its underlying mechanisms remain incompletely elucidated. This study employed monocrotaline (MCT), a well-established PA, to investigate the pathogenesis of PAs-ILI in a mouse model. Utilizing RNA-seq, Western blot, ROS detection, mitochondrial membrane potential and ATP assays, GSH quantification, transmission electron microscopy, and qRT-PCR, we demonstrated that MCT induced marked liver injury, as indicated by elevated serum biomarkers and histopathological changes. MCT provoked hepatic oxidative stress, characterized by increased ROS and significant suppression of thioredoxin 1 (TRX1), leading to mitochondrial dysfunction evidenced by reduced ATP production, membrane potential depolarization, and activation of the ASK1-JNK pro-apoptotic pathway. In vitro experiments in HepG2 cells confirmed MCT-induced DNA damage and ASK1-dependent JNK phosphorylation, underscoring the central role of this pathway in cytotoxicity. Pretreatment with the ASK1 inhibitor Selonsertib (SEL) attenuated MCT-induced liver injury by suppressing ASK1-JNK activation and preserving mitochondrial integrity. These results indicate that MCT elicits hepatotoxicity via TRX1-ASK1-JNK axis-mediated mitochondrial damage, and that SEL disrupts this cascade, highlighting the therapeutic potential of ASK1 inhibition in PAs-ILI.