Fig. 5
The function of histamine in the cardiac differentiation is mediated by the histamine 1 receptor. a The expression of H1R and H2R during cardiac differentiation was confirmed by immunoblot. Representative images and the densitometric analysis are shown. b Immunofluorescence staining for H1R, H2R, and NKX2.5 in hiPSCs and hiPSC-CPCs. Scale bar 100 μM. c Percentages of α-actinin+ cardiomyocytes on day 10 in the total population derived from iPSCs with or without pyrilamine and cimetidine treatment analyzed by FACS. d The mRNA levels of cardiogenic markers in hiPSC-CMs on day 10 with histamine and pyrilamine treatment. e The protein levels of α-actinin and cTnT in hiPSC-CMs on day 10 of differentiation. f Representative immunofluorescence images of а-actinin+ hiPSC-CMs. Scale bar 100 μM. g Representative immunostaining images of MEF2C (red), NKX2.5 (green), and nuclei (blue), in hiPSC-CPCs at day 5 of differentiation. Scale bar 200 μM. h The protein levels of GATA4, MEF2C, and NKX2.5 in hiPSC-CPCs on day 5. i Percentages of NKX2.5+ cells on day 5 in the total population derived from both hiPSC lines with or without histamine and pyrilamine treatment. Data are expressed as the mean ± SEM. *p < 0.05, **p < 0.01 vs control, #p < 0.05 vs His (n = 3 for each group)