USP15 and metabolic dysfunction-associated steatotic liver disease: Researchers discovered that The expression of the deubiquitinating enzyme USP15 is upregulated in the livers of HFD-fed mice and in liver biopsy tissues from patients with NAFLD or NASH, whereas hepatocyte deletion of USP15 suppresses hepatic steatosis, inflammation, and fibrosis in a mouse model of NASH (133).