FIG. 2.

SIRT3 is a stress-responsive factor in cardiomyocytes. (A) Expression levels of SIRT3 in cardiomyocytes grown for 48 h in a medium with serum or defined medium without serum. Note induction of ∼44-kDa band but not 28-kDa band of SIRT3 in serum-free medium. (B) SIRT3 levels in cardiomyocytes treated with vehicle (Cont.) or MNNG at indicated concentrations for 24 h. (C) SIRT3 levels in cardiomyocytes treated with different concentrations of H₂O₂ for 24 h. (D and E) SIRT3 levels in cardiomyocytes treated with Ang-II (D) (5 μM) or PE (E) (20 μM) for 48 h. (F) Immunostaining of cardiomyocytes for ANF release from nuclei (white), a marker of cellular stress. Positions of nuclei were determined by DAPI staining. Values are means ± standard errors of three to four experiments. SIRT3 antibody AP6242a was used for Western analysis.