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 cellreplacement therapy for lung degenerative diseases. The extracellular matrix (ECM) pro-vides a dynamic environmentand 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 embryonicstem cell (ESC) differentiation toward the tissue-specific lineages during in vitro culture. Therefore, the aim of this studywas to evaluate the effect of sheep lung dECM-derived scaffold on differentiation and further maturation of ESC-derivedlung progenitor cells.

This study was an experimental study. In the first step, a sheep lung was decellularizedto achieve dECM scaffolds and hydrogels. Afterwards, the obtained dECM scaffold was evaluated for collagen andglycosaminoglycan contents, DNA quantification, and its ultrastructure. Next, the three experimental groups: i. Sheeplung dECM-derived scaffold, ii. Sheep lung dECM-derived hydrogel, and iii. Fibronectin-coated plates were comparedin 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 chainreaction (PCR) assessments.

We found that the dECM-derived scaffold preserved its composition and native porous structures whilelacking nuclei and intact cells. All experimental groups displayed lung progenitor cell differen-tiation as revealed by theRNA and protein expression of NKX2.1, P63 and CK5. DE cells differenti-ated on dECM-derived scaffold and dECMderivedhydrogel 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 expressionof 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 towardslung alveolar progenitor cells in comparison with dECM-derived hydrogel and fibronectin-coated plates.