Differential inducibility of human and porcine dental pulp-derived cells into odontoblasts

A robust method for generating odontoblasts from cultured dental pulp cells has not been established. In this study, efficient methods for deriving odontoblasts from cultured human and porcine dental pulp-derived cells were investigated with special attention to species differences. Cultured human cells showed relatively low alkaline phosphatase (ALP) activity in the presence of dexamethasone (Dex) and beta-glycerophosphate (beta-Gly). In contrast, the addition of 1,25-dihydroxyvitaminD(3) (VitD3) significantly increased the ALP activity. In porcine cells, beta-Gly alone or a combination of Dex and beta-Gly significantly increased ALP activity; however, addition of VitD3 reduced this activity. RT-PCR and Western blotting analysis revealed that the combination of three induction reagents on human cells significantly upregulates the expression of osteocalcin mRNA, and dentin sialoprotein. We propose that the combination of Dex, beta-Gly, and VitD3 is critical for differentiation of human dental pulp-derived cells into odontoblasts. In addition, the inducibility of dental pulp-derived cells presented remarkable species differences.