Engineered hydrogel biomaterials facilitate lung progenitor cell differentiation from induced pluripotent stem cells

Lung progenitor (LP) cells identified by the expression of transcription factor NK2 homeobox 1 (NKX2.1) are essential for development of all lung epithelial cell types and hold tremendous potential for pulmonary research and translational regenerative medicine applications. Here we present engineered hydrogels as a promising alternative to the naturally derived materials that are often used to differentiate human induced pluripotent stem cells (iPSCs) into LP cells. Poly(ethylene glycol) norbornene (PEGNB) hydrogels with defined composition were used to systematically investigate the role of microenvironmental stiffness, cell origin, and splitting during the differentiation process. Results demonstrated that each of these factors impacted LP differentiation efficiency. Soft hydrogels replicating healthy lung stiffness (E = 4.00  0.25 kPa) produced the highest proportion of LP cells (54% by flow cytometry), stiff hydrogels (E = 18.83  2.24 kPa) resulted in 48% differentiation efficiency, and a thin coating of Matrigel on tissue culture (TC) plastic (E~3 GPa) resulted in the lowest proportion of LP cells (32%) at the end of the non-split differentiation protocol. Collectively these results showed that engineered hydrogels enable researchers to control parameters that impact cell differentiation and produce LP cells using well-defined microenvironments that may improve our ability to translate iPSC-derived LP cells into clinical applications.