Retrorsine Induces Hepatotoxicity through ATF3-Mediated Ferroptosis in Mouse Primary Hepatocytes and CYP3A4-HepG2 Cells.

Pyrrolizidine alkaloids (PAs) enter the food chain mainly through contaminated agricultural products, posing a global health risk. Given that ferroptosis─a form of cell death characterized by glutathione depletion─is involved in toxicant-induced liver injury and that retrorsine (RTS, a typical toxic PA) depletes glutathione, we investigated whether RTS induces hepatotoxicity via ferroptosis. This study demonstrates that RTS induces acute hepatotoxicity and ferroptosis in vivo and in vitro, RTS triggers mitochondrial dysfunction and activates activate transcription factors 3 (ATF3), which translocate to the nucleus and is associated with repression of phospholipase A2 group VI (PLA2G6) expression. Genetic manipulation of ATF3, through either knockdown or overexpression, consistently sensitized CYP3A4-HepG2 cells to RTS-induced cytotoxicity. In contrast, its downstream target PLA2G6 exerted a clear protective effect. These findings identify the ATF3-PLA2G6 axis as a key regulatory pathway associated with RTS-induced ferroptosis, and suggest that PLA2G6 may function downstream of ATF3 to modulate hepatotoxicity.