Fig. 4. Harmine reverses the effect of NE on cell size of hESC-derived cardiomyocytes.

a Schematic illustrating the differentiation protocol for H7 hESC line into cardiomyocytes in chemically defined medium. b The dose-dependent effect of harmine on beating rates of NE (20 μM) treated cardiomyocytes for 24 h. IC₅₀ value for harmine was 25.45 ± 2.122 μM (n = 3 for each dose). c Representative immunostaining images of hESC-derived cardiomyocytes stained with cTnT (green) for sarcomere maker and DAPI (blue) for nuclei. Scale bars, 100 μm. d Stimulation with NE (20 μM) for 3 days leads to an increase in cell size, while a reduction after pre-treated with harmine (10 μM) for 3 h and then co-treated with NE for 3 days (n > 400 per group). Data are mean ± SEM. ****P < 0.0001; by two-tailed Student’s t test.