Geranylgeraniol Induces PPARγ Expression and Enhances the Biological Effects of a PPARγ Agonist in Adipocyte Lineage Cells

Background: The global incidence of diabetes mellitus (DM) has risen precipitously, even in middle- and low-income countries. Peroxisome proliferator-activated receptor gamma (PPAR gamma) plays an important role in the control of cellular glucose metabolism. Activation of PPAR gamma beneficially results in increased insulin sensitivity. However, the expression of PPAR gamma is reduced by obesity and several nutritional factors. Here we examined the effect of geranylgeraniol (GGOH), a bioactive compound found naturally in fruits, vegetables, and grains, on the expression and activation of PPAR gamma. Materials and Methods: C3H10T1/2 mouse embryonic fibroblasts and 3T3-L1 pre-adipocytes were used as in vitro models of adipocyte differentiation and function. Quantitative reverse-transcriptase polymerase chain reaction, western blotting, Oil Red O staining, and luciferase assay were performed to respectively assess mRNA expression, protein levels, lipid droplet formation and transcriptional activity. Results: GGOH increased the expression of PPAR gamma in adipocyte lineage cells. GGOH also enhanced adipogenesis induced by rosiglitazone, a thiazolidinedione class PPAR gamma agonist. Conclusion: GGOH induces PPAR gamma expression and enhances the biological effects of a PPAR gamma agonist in adipocyte lineage cells.