PRMT3-mediated post-translational adaptation to fasting regulates metabolic flexibility.

Obesity impairs metabolic flexibility-the capacity to adapt to fluctuating energy demands. Emerging evidence suggests that dietary interventions, particularly time-restricted feeding (TRF), may help restore this flexibility. In this study, we demonstrate that feeding upregulates PRMT3 and asymmetric dimethylarginine (ADMA)-containing proteins via insulin-pAKT signaling, while fasting reduces their expression. Pharmacological inhibition of PRMT3 attenuates diet-induced obesity (DIO) and enhances adipocyte glycolysis in male mice. Mechanistically, PRMT3 drives the expression of citrate transporter SLC25A1 during feeding through direct arginine methylation. A 16:8 TRF regimen normalizes PRMT3 and ADMA levels while suppressing SLC25A1 expression. Notably, PRMT3 inhibition recapitulates the metabolic benefits of 16:8 TRF and improves metabolic flexibility. Furthermore, adipocyte-specific deletion of Slc25a1 in male mice protects against DIO and enhances insulin sensitivity. Collectively, these findings identify PRMT3-mediated arginine methylation in vWAT as a nutrient-responsive regulatory axis that impairs metabolic flexibility in obesity, which is a potential therapeutic target.