Long non-coding RNA G23Rik attenuates fasting-induced lipid accumulation in the liver

Peroxisome proliferator-activated receptor (PPAR) is a key mediator of lipid metabolism and metabolic stress in the liver. A recent study revealed that PPAR-dependent long non-coding RNAs (lncRNAs) play an important role in modulating metabolic stress and inflammation in the livers of fasted mice. Here hepatic lncRNA 3930402G23Rik (G23Rik) was found to have active peroxisome proliferator response elements (PPREs) within its promoter and is directly regulated by PPAR. Although G23Rik RNA was expressed to varying degrees in several tissues, the PPAR-dependent regulation of this lncRNA was only observed in the liver. Pharmacological activation of PPAR induced PPAR recruitment at the G23Rik promoter and a pronounced increase in hepatic G23Rik lncRNA expression. A G23Rik-null mouse line was developed to further characterize the function of this lncRNA in the liver. G23Rik-null mice were more susceptible to hepatic lipid accumulation in response to acute fasting. Histological analysis further revealed a pronounced buildup of lipid droplets and a significant increase in neutral triglycerides and lipids as indicated by enhance oil red O staining of liver sections. Hepatic cholesterol, non-esterified fatty acid, and triglyceride levels were significantly elevated in G23Rik-null mice and associated with induction of the lipid-metabolism related gene Cd36. These findings provide evidence for a lncRNA dependent mechanism by which PPAR attenuates hepatic lipid accumulation in response to metabolic stress through lncRNA G23Rik induction. Key pointsO_LI3930402G23Rik (G23Rik) is a liver-enriched long non-RNA. C_LIO_LIG23Rik is a PPARA target gene. C_LIO_LILoss of G23Rik increases hepatic lipid accumulation during fasting C_LI