Arylacetamide deacetylase plays a protective role against amodiaquine-induced liver injury by suppressing ferroptosis.

Amodiaquine (AQ), an antimalarial drug, is metabolized by cytochrome P450 3A4 (CYP3A4) to quinoneimine forms, which are proposed to cause liver injury; however, the underlying mechanism remains unclear. Ferroptosis, a type of regulated cell death driven by iron-dependent lipid peroxidation, has been implicated in certain cases of drug-induced liver injury. Arylacetamide deacetylase (AADAC), a drug-metabolizing hydrolase, regulates hepatic iron homeostasis through non-enzymatic mechanisms and may protect against ferroptosis-associated drug-induced liver injury. This study aimed to elucidate the involvement of ferroptosis in AQ-induced liver injury and to assess the impact of AADAC deficiency. Oral administration of 150 mg/kg AQ with l-buthionine-(S,R)-sulfoximine, a glutathione synthesis inhibitor, induced liver injury in 42% of female C57BL/6J mice, as indicated by plasma alanine aminotransferase levels exceeding 1000 U/L-these were defined as high-responders. Pretreatment with either a P450 inhibitor (1-aminobenzotriazole) or a ferroptosis inhibitor (deferoxamine) resulted in no mice with high plasma alanine aminotransferase levels by AQ treatment, suggesting that quinoneimine formations lead to ferroptosis-associated liver injury. Furthermore, Aadac knockout mice had a higher proportion of high-responders compared with wild-type mice, reinforcing the involvement of ferroptosis in AQ-induced liver injury. In human hepatocarcinoma-derived HepG2 cells overexpressing CYP3A4, pretreatment with deferoxamine effectively prevented AQ-induced cytotoxicity. Overexpression of AADAC also attenuated AQ-induced cytotoxicity in CYP3A4-expressing HepG2 cells, indicating a protective role for AADAC against AQ-induced ferroptosis in humans. In conclusion, this study demonstrates that AQ-induced liver injury is mediated by ferroptosis through P450-dependent metabolism and highlights a protective function of AADAC against AQ-induced ferroptosis.