Protocol for the differentiation of human alveolar epithelial type I cells from pluripotent stem cell-derived type II-like cells

Pulmonary alveolar epithelial type I (AT1) cells have a flattened morphology to permit the diffusion of oxygen into the capillaries and historically have been difficult to isolate or maintain in culture. Here, we present a protocol for generating human alveolar type I-like cells (induced pluripotent stem cell-derived AT1s [iAT1s]) from induced pluripotent stem cell-derived alveolar epithelial type II cells (iAT2s) in vitro. We describe steps to plate iAT1s in either 3D or air-liquid interface cultures and to analyze or isolate iAT1s via flow cytometry. For complete details on the use and execution of this protocol, please refer to Burgess et al.¹.