USP25 and fatty liver disease: Notably, the mRNA levels of downstream targets of Pparα (acyl-Coenzyme A oxidase 1, carnitine palmitoyltransferase 1α, and fatty acid binding protein 1) were also significantly reduced (Fig. 3I), suggesting that USP25 may influence hepatic steatosis through PPARα regulation, given the pivotal role of Pparα in lipid beta-oxidation (19).