Figure 3. SB431542 and XAV939 enhance the quality and speed of cardiac reprogramming in vitro.
(A) Quantification of percent beating cardiomyocytes over time showing that SB431542 and XAV939 accelerate the appearance of spontaneously beating cells as early as 1 week and increase the number of beating cells (n=3 independent experiment, *p<0.05, GMT (Blue), GMT + SB431542 (Green), GMT + XAV939 (Purple), GMT + SB431542 + XAV939 (Red)) (B) Within 2 weeks of reprogramming, troponin T and enhanced sarcomere organization were observed in the GMT + SB431542 + XAV939 group, but not in other settings (scale bar 50 µm). (C) Calcium transients from spontaneously contracting iCMs loaded with Fluo-4 calcium dye (Movie S3) (1 and 2 from two adjacent cells that beat at different rates) after 3 weeks of reprogramming, and quantification of the percentage of iCMs that exhibit spontaneous calcium transients over 8 weeks of reprogramming (n=200 cells analyzed at each time point from two independent experiments, *p<0.05 compared to GMT).