Bovine Stearoyl-CoA Desaturase 1 Promotes Adipogenesis by Activating the PPARγ Receptor

Stearoyl-CoA desaturase 1 (SCD1) is a rate-limiting enzyme that mainly catalyzes the saturated fatty acids (SFAs) into the monounsaturated fatty acids (MUFAs). The expression level of SCD1 is positively correlated with the marbling score. However, the functional mechanism of SCD1 in adipogenesis is still unclear. In this study, we identified SCD1 as highly expressed in subcutaneous and visceral fat, peaking at 2 days after differentiation in bovine stromal vascular fraction (SVF) cells. When the SCD1 was overexpressed in bovine SVF cells, lipid droplets accumulation was increased from 142.46 +/- 21.77 to 254.89 +/- 11.75 mu g/mg (P < 0.01). Further, the expression levels of FABP4, FASN, and ACCa were increased (P < 0.01), while the expression of PPAR gamma or C/EBPa was not changed at mRNA or protein level (P > 0.05). Dual-luciferase reporter assay showed that the activity of the PPAR gamma receptor was enhanced by 3.69 times (P < 0.01). Moreover, the contents of palmitoleate (C16:1) and oleate (C18:1) were significantly increased (P < 0.05). Furthermore, 100 mu M exogenous oleate increased the lipid accumulation by 22.28 times (P < 0.01). These results suggest that oleate is probably a strong ligand of the PPAR gamma receptor to enhance adipogenesis.