Fig. 2.

Evaluation of cardiac characteristics in hPSC-derived CMs. The expression of cardiac-specific genes was evaluated at the mRNA and protein level. Each stage of differentiation in hPSCs demonstrated expression of critical cardiac cascade genes. A Immunostaining of hPSC-derived CMs. Expression of cardiac specific genes in hESC-derived (a–e) and hiPSC-derived CMs (f–j) at each stage. Cardiac transcription factor Nkx2.5, protein for contraction cardiac troponin I (cTnI), structural protein αMHC, and the cardiomyocyte secreting protein ANF were immunolabeled and evaluated using laser scanning microscopy. Images were captured at 200× magnification (insets) and enlarged images at 800× magnification are represented. a, f Stage 1(day 12), Nkx2.5 (green), cTn I (red); b, g stage 2 (day 18), Nkx2.5 (green), αMHC (red); d, i stage 3 (day 24), Nkx2.5 (green), ANF (red). Images of replated hESC-derived (c, e) and hiPSC-derived CMs (h, j) were captured at 200× magnification (insets) and enlarged images at 1,200× magnification are represented. c, h Stage 2 (day 18), Nkx2.5 (green), αMHC (red); e, j stage 3 (day 24), Nkx2.5 (green), ANF (red). B Expression of cardiac specific genes in hPSC-derived CMs using qRT-PCR. Expression level was normalized to GAPDH and run in triplicate. C Positive populations for Nkx2.5 and αMHC were evaluated. More than 60 % of differentiated cells were positive for Nkx2.5 and αMHC as measured by FACS analysis