Prostaglandin D enhances lipid accumulation through suppression of lipolysis via DP2 (CRTH2) receptors in adipocytes.

Prostaglandin (PG) D enhanced lipid accumulation in adipocytes. However, its molecular mechanism remains unclear. In this study, we investigated the regulatory mechanisms of PGD-elevated lipid accumulation in mouse adipocytic 3T3-L1 cells. The Gi-coupled DP2 (CRTH2) receptors (DP2R), one of the two-types of PGD receptors were dominantly expressed in adipocytes. A DP2R antagonist, CAY10595, but not DP1 receptor antagonist, BWA868C cleared the PGD-elevated intracellular triglyceride level. While, a DP2R agonist, 15R-15-methyl PGD (15R) increased the mRNA levels of the adipogenic and lipogenic genes, and decreased the glycerol release level. In addition, the forskolin-mediated increase of cAMP-dependent protein kinase A (PKA) activity and phosphorylation of hormone-sensitive lipase (HSL) was repressed by the co-treatment with 15R. Moreover, the lipolysis was enhanced in the adipocyte-differentiated DP2R gene-knockout mouse embryonic fibroblasts. These results indicate that PGD suppressed the lipolysis by repression of the cAMP-PKA-HSL axis through DP2R in adipocytes.