Differentiation potential and characterization of dental epithelial cells derived from human deciduous dental pulp

Background Deciduous tooth pulp derived epithelial stem–like cells (DPESCs) have been reported to be an alternative type of dental epithelial cell that can be used for tooth regeneration. The epithelial cell characteristics and differentiation capacity of rodent odontoblastic cells have been reported previously; however, the ability of these cells to differentiate from human dental stem cells has not been reported. Method DPESCs were cocultured with dental pulp stem cells from deciduous teeth (dDPSCs) to induce differentiation through epithelial‒mesenchymal interactions. Differentiation patterns were compared between dDPSCs cocultured with DPESCs and dDPSCs alone. To confirm the ability of DPESCs to induce differentiation in dental epithelial cells, induced pluripotent stem cells (iPSCs) were differentiated into dental epithelial cells on a DPESC feeder layer treated with mitomycin C. Established epithelial-like cells (DDes) were characterized and differentiated with dDPSCs. Results DPESCs cocultured with dDPSCs showed a differentiation pattern with significantly high expression of amelo-/odontogenic differentiation markers such as KLK4 , ENAM , Amelogenin , OCN , DMP1 , and DSPP 8 days after differentiation induction. DSPP protein was also highly expressed in the cocultured DPESCs with dDPSCs. Calcium deposits were observed later than in cocultured DPESCs with dDPSCs than in HERS/ERM cells but were observed in all three DPESC lines during the long differentiation period. DPESC could form a hard tissue structure 12 weeks after in vivo transplantation. iPSCs on the DPESC feeder layer successfully differentiated into epithelial-like cells, and DDes expressed epithelial stem cell markers such as E-cadherin , ABCG2 , EpCAM , Bmi1 , and p75 , as well as stemness-related markers such as Oct-4 , Nanog , and Sox-2 , similar to HERS/ERM cells. In DDes cocultured with dDPSCs, the expression of the KLK4 , ENAM , OCN , DMP1 , and DSPP genes and DSPP protein increased 8 days after differentiation induction, and mineralization was detected 20 days after differentiation induction. Conclusions The results confirmed the differentiation capacity of DPESCs through epithelial‒mesenchymal interactions and the epithelial differentiation ability of DPESCs. These results suggest that both the epithelial cells and mesenchymal stem cells necessary for tooth regeneration can be secured through the preservation of deciduous teeth.