Background and aims: Mitochondrial cholesterol (mChol) accumulation is associated with chronic liver diseases, including fatty liver disease and hepatocellular carcinoma. Increased cholesterol trafficking to mitochondria alters membrane physical properties, including the transport of cytosol GSH into mitochondrial matrix, which results in mitochondrial GSH (mGSH) depletion. As GSH is a critical player in drug-induced liver injury (DILI), we hypothesized that altered mChol homeostasis contributes to DILI. Valproic acid (VPA) is a widely prescribed epileptic and anticonvulsant drug, and patients under VPA therapy have been shown to develop acetaminophen (APAP) hepatotoxicity. Therefore, our aim was to examine the role of targeting cholesterol by statins and its trafficking to mitochondria mediated by StARD1 in VPA sensitization to APAP-mediated hepatotoxicity and acute liver failure. Method: WT C57BL/6J male mice were fed with normal chow (Ctrl) or high-cholesterol diet (2% Cholesterol and 0, 5% Sodium Cholate, HC) followed by a single dose of APAP (300 mg/Kg, ip). Mice were dosed daily by oral gavage with atorvastatin (Pfizer, 10 mg/kg) or vehicle 7 days before being treated three times every 12 h with VPA (400 mg/Kg, sc) followed by a single dose of APAP (300 mg/Kg, ip). Moreover, mice with hepatocyte-specific StARD1 deletion (StARD1¿Hep) were analysed for VPA sensitization to APAP mediated hepatotoxicity. Liver damage by ALT and HandE, cholesterol trafficking and GSH homeostasis were examined following VPA plus APAP cotreatment. Expression of StARD1, MLN64, ER stress markers and lipogenic transcription factors were examined by qPCR and WB. Results: Mice fed a cholesterol-enriched (HC) diet, which exhibited enhanced hepatic cholesterol loading in mitochondria, were highly sensitive to APAP-induced liver injury, determined by serum ALT levels and HandE. Livers from HC+APAP displayed increased mChol transporters and ER stress markers expression and mChol accumulation, resulting in GSH depletion. Interestingly, atorvastatin therapy prevented the mChol loading and reduced the expression of StARD1, MLN64 and ER stress markers in mice treated with VPA+APAP. Atorvastatin therapy protected mice from VPA plus APAP liver injury, revealed by the HandE staining and the significant serum ALT decrease. Moreover, StARD1¿Hep mice were resistant to VPA+APAP mediated hepatotoxicity, exhibiting decreased mChol accumulation and mGSH repletion compared to StARD1 f/f mice. Conclusion: Cholesterol exacerbates liver toxicity following APAP administration and its targeting by atorvastatin protects against the hepatotoxic effects of VPA-induced sensitization to APAP hepatotoxicity. Similar findings are observed in StARD1¿Hep mice indicating that the selective mChol pool plays an important role in DILI.

Trabajo presentado en el International Lipid Signaling and Oxidative Stress in Pathology Symposium, celebrado en Barcelona (España), los días 1 y 2 de diciembre de 2022