SCOPE: To study the effects of Maresin 1 (MaR1), a docosahexaenoic-acid-derived lipid mediator, on fibroblast growth factor 21 (FGF21) production and to characterize the tissue-specific regulation of Fgf21 and its signaling pathway in liver, skeletal muscle, and white adipose tissue (WAT).
METHODS AND RESULTS: Diet-induced obese (DIO) mice are treated with MaR1 (50g kg-1 , 10 days, oral gavage) and serum FGF21 levels and liver, muscle and WAT Fgf21, beta-Klotho, Fgfr1, Egr1, and cFos mRNA expression are evaluated. Additionally, MaR1 effects are tested in mouse primary hepatocytes, HepG2 human hepatocytes, C2C12 myotubes, and 3T3-L1 adipocytes. In DIO mice, MaR1 decreases circulating FGF21 levels and HFD-induced hepatic Fgf21 mRNA expression. MaR1 increases hepatic beta-Klotho, Egr1, and cFos in DIO mice. In WAT, MaR1 counteracts the HFD-induced downregulation of Fgf21, Fgfr1, and beta-Klotho. In muscle, MaR1 does not modify Fgf21 but promoted Fgfr1 expression. In mouse primary hepatocytes, MaR1 decreases Fgf21 expression and downregulated Pparalpha mRNA levels. In HepG2 cells, MaR1 reverses the increased production of FGF21 and the downregulation of FGFR1, Beta-KLOTHO, EGR1, and cFOS induced by palmitate. Preincubation with a PPARalpha antagonist prevents MaR1 effects on FGF21 secretion.
CONCLUSION: The ability of MaR1 to modulate FGF21 can contribute to its beneficial metabolic effects.