FGF21 and fatty liver disease: HFD-induced hepatic steatosis was significantly attenuated by the treatment with adiponectin-expressing tTreg precursors, as demonstrated by histological staining, tissue lipid measurement and mRNA quantification of genes encoding fibroblast growth factor 21 (FGF21) or peroxisome proliferator-activated receptor alpha (PPARA) (Fig. 6c).