Decellularized Lung Extracellular Matrix Scaffold Promotes Human Embryonic Stem Cell Differentiation towards Alveolar Progenitors.

Efficient production of functional and mature alveolar epithelial is a major challenge for developing any cell replacement therapy for lung degenerative diseases. The extracellular matrix (ECM) pro-vides a dynamic environment and mediates cellular responses during development and maintenance of tissue functions. The decellularized ECM (dECM) which retains its native-like structure and bio-chemical composition can provide the induction of embryonic stem cell (ESC) differentiation toward the tissue-specific lineages during in vitro culture. Therefore, the aim of this study was to evaluate the effect of sheep lung dECM-derived scaffold on differentiation and further maturation of ESC-derived lung progenitor cells. This study was an experimental study. In the first step, a sheep lung was decellularized to achieve dECM scaffolds and hydrogels. Afterwards, the obtained dECM scaffold was evaluated for collagen and glycosaminoglycan contents, DNA quantification, and its ultrastructure. Next, the three experimental groups: i. Sheep lung dECM-derived scaffold, ii. Sheep lung dECM-derived hydrogel, and iii. Fibronectin-coated plates were compared in their abilities to induce further differentiation of human embryonic stem cells (hESCs)-derived definitive endoderm (DE) into lung progenitor cells. The comparison was evaluated by immuno-staining and real-time polymerase chain reaction (PCR) assessments. We found that the dECM-derived scaffold preserved its composition and native porous structures while lacking nuclei and intact cells. All experimental groups displayed lung progenitor cell differen-tiation as revealed by the RNA and protein expression of NKX2.1, P63 and CK5. DE cells differenti-ated on dECM-derived scaffold and dECMderived hydrogel showed significant upregulation of SOX9 gene expression, a marker of the distal airway epithelium. DE cells differentiated on the dECM-derived scaffold compared to the two other groups, showed enhanced expression of SFTPC (type 2 alveolar epithelial [AT2] cell marker), FOXJ1 (ciliated cell marker), and MUC5A (secretory cell marker) genes. Overall, our results suggest that dECM-derived scaffold improves the differentiation of DE cells towards lung alveolar progenitor cells in comparison with dECM-derived hydrogel and fibronectin-coated plates.