Figure 8. Nicotinamide mononucleotide (NMN)treatment preserves NAD+ and prevents senescence in human retinal pigment epithelial cells. Human retinal pigment epithelial cells (ARPE-19) were treated with 10μM FK866 alone or in combination with different doses of NMN (0.05-1 mM) for 72 hr. (A) NAD+ content was measured using a NAD assay kit. (B) Changes in expression of SIRT1, p16INK4a and p21Waf/Cip1 proteins levels were evaluated by western blotting. (C-D) RPE senescence was evaluated by β-galactosidase staining. A representative western blot image from three replicates is shown. Data are presented as mean ± S.E.M for n=3 independent experiments. *p<0.05 compared to CON (Vehicle treated) and #p<0.05 compared to FK866.