Differentiation of adipose-derived adult stem cells into epithelial-like stem cells

Adipose-derived adult stem (ADAS) cells can be easily obtained in large quantities. Previous studies have suggested that all-trans-retinoic acid (ATRA) plays an important role in the differentiation of mesenchymal stem cells toward an epithelial lineage. In order to verify that ADAS-cells can differentiate into an epithelial lineage retaining most of the characteristics of stem cells, ADAS-cells were isolated and cultured. They were induced to differentiate toward an epithelial lineage in vitro. Differentiated epithelial cells were assayed as to whether they retain characteristics of stem cells by RT-PCR and cell cycle stage analysis, and were further induced to differentiate toward an osteogenic lineage. RT-PCR analysis revealed that no CK5, CK10 or CK19 mRNA was detected in ADAS-cells, CK19 but not CK5 or CK10 mRNA was detected in differentiated cells at passage 1, CK10 and CK19 expression but not CK5 mRNA was detected in differentiated cells at passage 10. After induction, the expression of CK19 was observed by immunofluorescent staining. Positive staining with alkaline phosphatase (ALP) and Von Kossa staining verified that differentiated epithelial cells still had potential to further differentiate toward an osteogenic lineage. These experiments provide proof that ADAS-cells can differentiate into an epithelial lineage retaining most of the characteristics of stem cells.