Figure 4
Characterization of hiPSC-derived alveolar like cells cultured under ALI conditions. (a) Change in TEER over 1 week of ALI culture. (b) Comparison of TEER values between primary human small airway cells (hSAEC), literature based human pulmonary alveolar epithelial cells (HPAEpiC) and the generated AT2-like cells. Median; range [min, max], N = 5; ns = not significant, ***p < 0.001, ****p < 0.0001. (c–k) Representative electron microscopy images of lamellar bodies in hiPSC-derived AT2 cells (white arrow heads c,d) of lamellar bodies showing classical lamellar structures (e). Typical microvilli structures at the surface of the cells (f) and characteristic multivesicular bodies indicated with white arrow heads (g). Tight cell–cell desmosome contacts indicated by the white arrow heads (h). (i–k) Apical tight junctions indicated by white arrow heads. M = mitochondria; N = nucleus; LB = lamellar body; MV = microvilli; MB = multivesicular body. Scale bar = 500 nm; magnification scale bars = 100 nm. (l–o) Exemplary surfactant expression in ALI versus submerged conditions (l,m) Immunofluorescence staining of SFTPB at day 27 of differentiation of hiPSC-derived AT2-like cells cultured under submerged or ALI conditions, respectively. (n,o) Immunofluorescence staining of SFTPC at day 27 of differentiation of hiPSC-derived AT2-like cells cultured under submerged or ALI conditions, respectively. Scale bars = 400 µm. (p) Comparison of submerged and ALI cultures, based on semi-quantitative analysis of SFTPB and SFTPC expressing cells.
