Figure 3. SIRT1 activation and SIRT1 inhibition have opposite effects on keratinocyte differentiation.
(a) NHEK cells treated with growth media (Control); nicotinamide (NAA) (8 mm), a SIRT1 inhibitor; DMSO, a control for resveratrol; resveratrol (RES) (3 µm), a SIRT1 activator. Cells were harvested at 80% confluence (80), 100% confluence (100), or 3 days after 100% confluence (+ 3D). A western blot was performed to determine the levels of involucrin and actin. (b and c) Statistical analysis of three biological replicates for NAA- and Res-treated NHEK cells shown in panel a. Panels b and c mean ± SEM for each treatment. NAA treatment reduces normalized involucrin abundance (t-test, P<0.05), and although not meeting the same level of statistical significance, resveratrol treatment trended toward increasing normalized involucrin abundance (t-test, P = 0.058).