Use of alveolar epithelial cells derived from induced pluripotent stem cell to study alveolar wound repair in vitro

The introduction of human induced pluripotent stem cells (hiPSCs) for the generation of various cell types allows the development of more realistic and patient-specific tissue models. A major advantage is the possibility to obtain multiple cell types with the same genetic background from the same hiPSC line. The aim of the present study was to develop alveolar epithelial type 2 (AT2) cells from hiPSCs in order to develop a model of alveolar wound repair. Therefore, hiPSCs were gradually differentiated towards an alveolar and endothelial fate by closely controlling the BMP, FGF, WNT, RA and TGF-β signalling pathways. First, definitive endoderm was induced over a period of 4 days, followed by the formation of anterior foregut endoderm and subsequently ventralized over a period of 12 days. Following ventralization, alveolar progenitors were generated during 8 days and finally the cells were exposed to dexamethasone and KGF for 4-6 weeks to induce expression of alveolar epithelial type 2 markers (surfactant proteins and LP-CAT 1) as well as lamellar bodies in about 20% of the cells. Using an EpCAM isolation we managed to setup a long-term culture of induced ATII cells at the air liquid interface (ALI). Using this setup we were able to visualize and monitor alveolar repair over the course of 2 weeks following mechanical wounding of the cultures. In a next phase of our research, we will compare wound repair of primary and hiPSC-derived ATII cells.