(a) A schematic illustration of expansion of alveolar stem cells by using LysoTracker. (b) Representative histograms of LysoTracker Red for each cell component of FD-AOs (EpCAM+SFTPC+ cells, EpCAM+SFTPC- cells, and mesenchymal cells). (c) RT-qPCR analysis of alveolar epithelial cell markers in FD-AOs derived from EpCAM+LysoTrackerhi cell population in five PSC lines compared with those in P1 FD-AOs derived from FD-SFTPC+ cells using genetic reporter (B2-3) -based cell sorting. The expression human fetal lung was set at 1. Error bars indicates the mean ± s.e.m (n=3 independent organoids, each). (d) A TEM image of lamellar bodies in P2 FD-AO derived from EPCAM+LysoTrackerhigh cells (n = 3 collected images). Scale bar, 2 μm. (e) Immunofluorescence images of AT2 markers in P2 FD-AO derived from EPCAM+LysoTrackerhi cells (n = 5 collected images). B2-3 and 648A1 hiPSC lines were used in (b) and (d) (e), respectively.