Fig. 1. γ-secretase inhibitor DAPT promoted differentiation of hiPSC-derived muscle progenitors.

a DAPT inhibited Notch signaling by inhibiting γ-secretase. b Experimental design-1. Hu5/KD3 cells were plated onto collagen-I-coated plates and cultured for 10 days in 10% FBS/DMEM with or without DAPT, and the fusion index was determined at day 10. c Representative photos of myotube formation by Hu5/KD3 cells with or without DAPT. d Quantification of fusion index in c. Data are expressed as dot plot in control (0.1% DMSO treatment) and DAPT (10 μM DAPT treatment) cells. Data were analyzed by unpaired two-tailed Student’s t-test. n = 3 samples/group. e Quantification of myotube diameter in (c). More than 10 myotubes were measured per group. Data were analyzed by an unpaired two-tailed Student’s t-test. In d, e, the effect size of Pearson’s r correlation (r) is shown. f Experimental design 2. After 6 weeks of sphere culture-based muscle induction, cells were plated onto collagen-I-coated plates and cultured for 7 days in 10% FBS/DMEM. Then ERBB3(+)CD271(+) cells as muscle progenitors were sorted by FACS. Sorted cells were cultured for a further 6 days with (10 μM) or without DAPT (0.1% DMSO). Induction and sorting of muscle progenitors was performed twice (2 experiments per group). g Representative photos of myotubes formed by hiPSC-derived ERBB3(+)CD271(+) cells with or without DAPT. h Quantification of fusion index in g. Three wells per sample were examined. The average of each sample was shown as dot. i Distribution of myotube diameter in g. Diameter of more than 15 myotubes per sample were measured. In c and g, myotubes were stained with an antibody against skeletal muscle myosin (MF20, red) and DAPI (Nuclei, blue). Scale bars, 200 μm.