Fig. 4.

Interactions between PPARα and Sirt1.

First, 100 ng of pGL6 constructs, 100 ng of pLasPPARα and siSirt1 constructs, and 2 ng of the Renilla luciferase plasmid pRL-TK were co-transfected into 293T cells. The relative luciferase activity was then assessed using a Spectrophotometer. MC3T3-E1 cells transfected with pLasPPARα and siSirt1 were incubated in OM and HG-FFA for 14 days for evaluation of the expression of PPARγ and PGC-1α. (A) PPARα overexpression significantly decreased the relative luciferase activity of both PPARγ and PGC-1α promoters. Silencing of Sirt1 increased the relative luciferase activity, whereas PPARα overexpression reversed this activity significantly. PPARα overexpression markedly reduced and reversed the mRNA (B) and protein (C, D) expression of PPARγ and PGC-1α induced by Sirt1 silencing. (D) The densitometry analysis of Western blot results. *** indicates P < 0.001; ** and ## indicate P < 0.01; * and # indicate P < 0.05. N = 3.