Comparison of pro-adipogenic effects between prostaglandin (PG) D2 and its stable, isosteric analogue, 11-deoxy-11-methylene-PGD2, during the maturation phase of cultured adipocytes.

ABSTRACT

Prostaglandin (PG) D2 is relatively unstable and dehydrated non-enzymatically into PGJ2 derivatives, which are known to serve as pro-adipogenic factors by activating peroxisome proliferator-activated receptor (PPAR) γ, a master regulator of adipogenesis. 11-Deoxy-11-methylene-PGD2 (11d-11m-PGD2) is a novel, chemically stable, isosteric analogue of PGD2 in which the 11-keto group is replaced by an exocyclic methylene. Here we attempted to investigate pro-adipogenic effects of PGD2 and 11d-11m-PGD2 and to compare the difference in their ways during the maturation phase of cultured adipocytes. The dose-dependent study showed that 11d-11m-PGD2 was significantly more potent than natural PGD2 to stimulate the storage of fats suppressed in the presence of indomethacin, a cyclooxygenase inhibitor. These pro-adipogenic effects were caused by the up-regulation of adipogenesis as evident with higher gene expression levels of adipogenesis markers. Analysis of transcript levels revealed the enhanced gene expression of two subtypes of cell-surface membrane receptors for PGD2, namely the prostanoid DP1 and DP2 (chemoattractant receptor-homologous molecule expressed on Th2 cells (CRTH2)) receptors together with lipocalin-type PGD synthase during the maturation phase. Specific agonists for DP1, CRTH2, and PPARγ were appreciably effective to rescue adipogenesis attenuated by indomethacin. The action of PGD2 was attenuated by specific antagonists for DP1 and PPARγ. By contrast, the effect of 11d-11m-PGD2 was more potently interfered by a selective antagonist for CRTH2 than that for DP1 while PPARγ antagonist GW9662 had almost no inhibitory effects. These results suggest that PGD2 exerts its pro-adipogenic effect principally through the mediation of DP1 and PPARγ, whereas the stimulatory effect of 11d-11m-PGD2 on adipogenesis occurs preferentially by the interaction with CRTH2.