FNDC5 and metabolic dysfunction-associated steatotic liver disease: NR (nicotinamide riboside) stimulates SIRT2, promotes SIRT2 deacetylation, and stabilizes Fndc5 to prevent HFD-induced NAFLD; SIRT2 also deacetylates and stabilizes CCAAT/enhancer-binding protein beta (C/EBPβ) to prevent NAFLD; alternatively, NAFLD can be treated by targeting the SIRT2-HNF4α pathway [43, 149, 150].