Seijo Uchijima, Yuusei Tahara, Soshi Shinohara, Miki Nakajima, Tatsuki Fukami
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 1,000 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 to 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.