Mitoquinone protects against acetaminophen-induced liver injury in an FSP1-dependent and GPX4-independent manner.

Mitochondrial oxidative stress has been a crucial mediator in acetaminophen (APAP)-induced hepatotoxicity. MitoQ, an analog of coenzyme Q10, is targeted towards mitochondria and acts as a potent antioxidant. This study aimed to explore the effect of MitoQ on APAP-induced liver injury and its possible mechanisms. To investigate this, CD-1 mice and AML-12 cells were treated with APAP. Hepatic MDA and 4-HNE, two markers of lipid peroxidation (LPO), were elevated as early as 2 h after APAP. Oxidized lipids were rapidly upregulated in APAP-exposed AML-12 cells. Hepatocyte death and mitochondrial ultrastructure alterations were observed in APAP-induced acute liver injury. The in vitro experiments showed that mitochondrial membrane potentials and OXPHOS subunits were downregulated in APAP-exposed hepatocytes. MtROS and oxidized lipids were elevated in APAP-exposed hepatocytes. We discovered that APAP-induced hepatocyte death and liver injury were ameliorated by attenuation of protein nitration and LPO in MitoQ-pretreated mice. Mechanistically, knockdown of GPX4, a key enzyme for LPO defense systems, exacerbated APAP-induced oxidized lipids, but did not influence the protective effect of MitoQ on APAP-induced LPO and hepatocyte death. Whereas knockdown of FSP1, another key enzyme for LPO defense systems, had little effect on APAP-induced lipid oxidation but partially weakened the protection of MitoQ on APAP-induced LPO and hepatocyte death. These results suggest that MitoQ may alleviate APAP-evoked hepatotoxicity by eliminating protein nitration and suppressing hepatic LPO. MitoQ prevents APAP-induced liver injury partially dependent of FSP1 and independent of GPX4.