FIGURE 5.

Induction of SIRT1 protein expression by FoxO1. A and B, FoxO1 depletion by siRNA decreases SIRT1 expression. VSMCs (A) or HEK293 cells (B) were transfected with 30 nm FoxO1 or FoxO3a siRNA or scrambled siRNA for 48 h. C and D, FoxO1 overexpression increases SIRT1 protein level. C, VSMCs were infected with adeno-FoxO1 or control adeno-GFP for 24 h. D, HEK293 cells in 100 × 20-mm tissue culture dishes were transiently transfected with 10 μg/dish of FoxO1 expression plasmid or control vector pcDNA3 for 24 h. E, SIRT2 and SIRT3 expression were unaffected by FoxO1 overexpression in VSMCs. Protein expression of the samples from two independent experiments was analyzed by Western blotting. Data shown are from one of 3–4 independent experiments.