Fibroblast Growth Factor-21 Regulates PPARγ Activity and the Antidiabetic Actions of Thiazolidinediones. Mus musculus

Fibroblast growth factor-21 (FGF21) is a circulating hepatokine that beneficially affects carbohydrate and lipid metabolism. Here we report that FGF21 is also an inducible, fed-state autocrine factor in adipose tissue that functions in a feed-forward loop to regulate the activity of peroxisome proliferator-activated receptor γ (PPARγ), a master transcriptional regulator of adipogenesis. FGF21-knockout (KO) mice display defects in PPARγ signaling including decreased body fat and attenuation of PPARγ-dependent gene expression. Moreover, FGF21-KO mice are refratory to both the beneficial, insulin-sensitizing effects and the detrimental weight gain and edema side effects of the PPARγ agonist rosiglitazone. This loss of function in FGF21-KO mice is coincident with a marked increase in the sumoylation of PPARγ, which reduces its transcriptional activity. Adding back FGF21 prevents sumoylation and restores PPARγ activity. Collectively, these results reveal FGF21 as a key mediator of the physiologic and pharmacologic actions of PPARγ. Overall design: RNA was prepared from epididymal white adipose tissue of Diet-induced Obesity (DIO) wild-type and FGF21-KO mice treated with rosiglitazone or vehicle for 14 days (2 pools of 2 mice per condition).