Fig. 2

HAND1 deficiency promoted SHF and its derived cardiomyocyte differentiation. A The percentage of NKX2.5-eGFP⁺ cells in WT and H1-KO cells at different time points of cardiomyocyte differentiation (n = 3). B, C Expression of FHF (B) and SHF (C) markers in early cardiomyocyte differentiation of WT and H1-KO cells. Relative to GAPDH expression (n = 3). Unpaired t test. D, E Expression of NKX2.5 (D) and ventricular, atrial and outflow tract cardiomyocyte (VCM, ACM and OFT) markers (E) in WT and H1-KO-derived day 30 cardiomyocytes. Relative to GAPDH expression (n = 3). Unpaired t test. F Western blot analysis of CX43 and MYL2 expression in WT and H1-KO-derived day 30 cardiomyocytes. GAPDH served as loading control. Corresponding uncropped full-length gels and blots are presented in Additional file 8: Fig. S8. G The percentage of MYL2⁺ cardiomyocytes in WT and H1-KO cells at differentiation day 30 (n = 5). H Immunofluorescence staining of NR2F2 in WT and H1-KO-derived day 30 cardiomyocytes. Scale bar = 100 μm. I The field potential and simulated action potential recorded by MEA in WT and H1-KO-derived day 30 cardiomyocytes. Black lines represented the field potential while red lines represented the simulated action potential. J Comparison of corrected APD90, APD50 and APD90/APD50 ratio in WT and H1-KO-derived day 30 cardiomyocytes (n ≥ 7). Unpaired t test. K The action potential paced by 1Hz recorded by whole-cell patch clamp in WT and H1-KO-derived differentiation day 30 cardiomyocytes. L Comparison of APD90 and APD50 in WT and H1-KO-derived day 30 cardiomyocytes (n ≥ 9). Unpaired t test. M Expression of ion channels of WT and H1-KO-derived differentiation day 30 cardiomyocytes. Relative to GAPDH expression (n = 3). Unpaired t test. *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001. n.s: non-significant