Differentiation media based on mRNA expression levels of endodermal and lung epithelial markers. (A): Differentiation protocols for the derivation of alveolar epithelial cells from mouse iPSCs using a dissociated seeding method. (B): Quantitative polymerase chain reaction analysis of lung epithelial markers on day 12. ∗, p < .05 versus D12-1; #, p < .01 versus D12-2; ▴, p < .01 versus D12-1. (C): Quantitative polymerase chain reaction analysis of lung epithelial markers in differentiated iPSCs D12-2 compared with the murine type II pneumocyte cell line MLE12 and mouse lung tissue. Expression ratios were normalized to the GAPDH expression level. Data are representative of three independent experiments. Note that the y-axis is a logarithmic scale. Abbreviations: Basic DM, basic differentiation medium; BSA, bovine serum albumin; CCSP, Clara cell secretory protein; FGF, fibroblast growth factor; GAPDH, glyceraldehyde-3-phosphate dehydrogenase; iPS, induced pluripotent stem; iPSC, induced pluripotent stem cell; SABM, small-airway basal medium; SPA, surfactant protein A; SPB, surfactant protein B; SPC, surfactant protein C; SPD, surfactant protein D; TTF-1, thyroid transcription factor 1.