Figure 3. Leptin activates the PPARα P2 Promoter in HepG2 Cells P1, P2 and P3 promoter constructs were transfected into HepG2 cells and treated for 24 hrs with a vehicle control or an increasing concentration of leptin (0,50, 500, 1000 ng/ml).

B) P1 and P2 promoter constructs were transfected into HepG2 cells and treated for 24 hrs with leptin (1000 ng/ml) and an increasing concentration of the STAT3 inhibitor PpYLKTK-mts (0,1,10 nM). C) Mutation of the Sp1 site blocks leptin activation of P2 promoter activity. P2 (P2-pGL3) and P2 promoter construct containing the mutated Sp1 response element (SP1M EcoRI-pGL3) was transfected into HepG2 cells and treated with leptin (1000 ng/ml) for 24 hrs. All values represent the mean of 6 independent experiments ±SEM. Statistical comparisons of luciferase activity between treatments relative to the untreated control were determined by ANOVA followed by Bonferroni post hoc analysis. (* p<0.05, ** p<0.001, *** p<0.001).