Effects of the Selective EP2 Receptor Agonist Omidenepag on Adipocyte Differentiation in 3T3-L1 Cells

We aimed at comparing the effects of omidenepag (OMD) with those of prostaglandin F (FP) receptor agonists (FP agonists) on adipogenesis in mouse 3T3-L1 cells. To evaluate the agonistic activities of OMD against the mouse EP2 (mEP2) receptor, we determined cAMP contents in mEP2 receptor-expressing CHO cells by using radioimmunoassays. Overall, 3T3-L1 cells were cultured in differentiation medium for 10 days and adipocyte differentiation was assessed according to Oil Red O-stained cell areas. Changes in expression levels of the adipogenic transcription factors Pparg, Cebpa, and Cebpb were determined by using real-time polymerase chain reaction (PCR). OMD at 0.1, 1, 10, and 40 μmol/L, latanoprost free acid (LAT-A) at 0.1 μmol/L, or prostaglandin F_2α (PGF_2α), at 0.1 μmol/L were added to cell culture media during adipogenesis. Oil Red O-stained areas and expression patterns of transcription factor targets of OMD or FP agonists were compared with those of untreated controls. The 50% effective concentration (EC₅₀) of OMD against the mEP2 receptor was 3.9 nmol/L. Accumulations of Oil Red O-stained lipid droplets were observed inside control cells on day 10. LAT-A and PGF_2α significantly inhibited the accumulation of lipid droplets; however, OMD had no effect on this process even at concentrations up to 40 μmol/L. LAT-A and PGF_2α significantly suppressed Pparg, Cebpa, and Cebpb gene expression levels during adipocyte differentiation. Conversely, OMD had no obvious effects on the expression levels of these genes. A selective EP2 receptor agonist, OMD, did not affect the adipocyte differentiation in 3T3-L1 cells, whereas FP agonists significantly inhibited this process.