Figure 4.

Silencing of Sirt1 by siRNA blocks niacin-mediated NO production. For silencing Sirt1, HAEC were transfected with Sirt1 siRNA for 48 h using commercially available and validated Sirt1 siRNA as described in Methods. Sirt1 siRNA was transfected, and control cells were incubated with niacin for 24 h. Cellular extracts were used for NO production assays. NO levels are expressed as nmol/0.5 mg cellular protein. Data are mean ± SE of 3 experiments. P-values shown are compared to the respective bar diagrams in the figure.