Human induced Pluripotent Stem Cell (hi-PSC) -derived cardiomyocytes transduced with adenoviruses containing green fluorescent protein (Ad.GFP), M1-SIRT3 (Ad.M1-SIRT3), M3-SIRT3 (Ad.M3-SIRT3), mutant M1-SIRT3 (Ad.mutM1-SIRT3), or mutant M3-SIRT3 (Ad.mutM3-SIRT3) for 24 h; treated with vehicle, DMSO (CON), or DOX (10 μM) for 24h and stained with MitoSOX (5 μM). Representative images of cardiomyocytes transduced with (A) Ad.GFP (B) Ad.M1-SIRT3 or Ad.M3-SIRT3 (C) Ad.mutM1-SIRT3 or Ad.mutM3-SIRT3 and treated with vehicle or DOX. (D) Quantification of mitochondrial reactive oxygen species levels determined by epifluorescence imaging. n = 4 biological replicates. Scale bars = 100 μm, Values are mean ± SD. Statistics are two-way ANOVA with Tukey’s post-hoc test.