FIGURE 5.
NAD treatment blocks the agonist-mediated cardiac hypertrophy independent of SIRT1. A, endogenous LKB1 was immunoprecipitated (IP) from heart lysates of mice treated with Ang-II, Ang-II plus NAD, or NAD alone. It was analyzed by Western blotting with anti-Ac-K antibody. The stripped blot was probed with anti-LKB1 antibody for loading control. B, expression of phospho (P)-LKB1 and phospho-AMPK in the hearts of wild-type and Sirt1−/− mice. Total LKB1 and AMPK were used as loading controls. Results are shown for two mice of each group. C, heart weight/body weight ratio of wild-type (WT) and Sirt1+/− mice treated with vehicle (cont.) ISO or ISO plus NAD for 7 days. D and E, quantification of cardiac fibrosis and the myocyte cross-sectional area in wild-type and Sirt1+/− mice subjected to different treatments. F, expression levels of SIRT1 in wild-type and Sirt1+/− hearts. G, Collagen-α and Anf mRNA levels in heart samples of wild-type and Sirt1+/− mice subjected different treatments. H, primary cultures of neonatal rat cardiomyocytes were pretreated with vehicle (control), 20 μm compound C (comp.c), or 50 μm splitomicin (splitom.) and then stimulated with PE in the absence or presence of NAD. Cells were subsequently labeled with [3H]leucine and incorporation of the isotope into total cellular proteins was measured 48 h after PE treatment. Bar diagrams represent values ± S.E. of five experiments.