Prostaglandin D2 enhances lipid accumulation through suppression of lipolysis via DP2 (CRTH2) receptors in adipocytes

Prostaglandin (PG) D2 enhanced lipid accumulation in adipocytes. However, its molecular mechanism remains unclear. In this study, we investigated the regulatory mechanisms of PGD2-elevated lipid accumulation in mouse adipocytic 3T3-L1 cells. The Gi-coupled DP2 (CRTH2) receptors (DP2R), one of the two-types of PGD2 receptors were dominantly expressed in adipocytes. A DP2R antagonist, CAY10595, but not DP1 receptor antagonist, BWA868C cleared the PGD2-elevated intracellular triglyceride level. While, a DP2R agonist, 15R-15-methyl PGD2 (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 PGD2 suppressed the lipolysis by repression of the cAMP-PKA-HSL axis through DP2R in adipocytes.