Differentiation of porcine mesenchymal stem cells into epithelial cells as a potential therapeutic application to facilitate epithelial regeneration

Epithelial denudation has been shown to be one of the characteristics of chronic asthma and airway remodeling. To restore its functions, the airway epithelium has to rapidly repair the injuries and regenerate its structure and integrity. Mesenchymal stem cells (MSCs) have been shown to differentiate into many different cell lineages. In this study, we examined and optimized the conditions for differentiation of MSCs into airway epithelial cells by using three defined cell culture media compositions with various growth supplementations. MSCs were isolated from porcine bone marrow by density gradient centrifugation. The cells were observed to be CD11b- CD34- CD45- CD73+ CD90+ and CD105+ by immunostaining and flow cytometry. MSCs were stimulated with EpiGRO (Millipore), BEpiCM (ScienCell), and AECGM (PromoCell) media for 5 days and 10 days, and epithelial differentiation into epithelial cells was assessed by fluorometry and flow cytometry using the epithelial cell specific markers, cytokeratin 7-8, cytokeratin 14-15-16-19, and epithelial cell adhesion molecule (EpCAM). The cells cultured in BEpiCM containing fibroblast growth factor and prostaglandin E2 showed the highest expression of the epithelial markers, CK7-8 (85.90%), CK-14-15-16-19 (10.14%), and EpCAM (64.61%). These studies suggest that stem cells isolated from bone marrow express epithelial markers and retain their differentiated phenotype when cultured ex vivo. In conclusion, the results from this study represent the first step to utilizing bone marrow-derived stem cells for facilitating the repair of denuded airways in asthmatic subjects.