Wnt11 expression in rat dental pulp and promotional effects of W nt signaling on odontoblast differentiation

Congenital anomalies of wingless‐type mouse mammary tumor virus ( MMTV) integration site family ( W nt) are frequently accompanied with tooth and dentin abnormality. The aim of this study was to investigate the effects of W nt signaling on odontoblast differentiation of mouse dental papilla cells ( MDPs ). Mouse dental papilla cells were cultured in α‐modified minimum essential medium containing 10% fetal bovine serum and antibiotics. Odontoblast differentiation was induced by bone morphogenic protein 2 ( BMP2 ), and the expression of odontoblast‐specific markers and Wnt‐related signaling molecules was analyzed by real‐time reverse transcription‐polymerase chain reaction and immunohistochemistry. Odontoblast differentiation was evaluated by dentin sialophosphoprotein ( D spp ) and dentin matrix protein ( DMP ) 1 expression. Localization of β‐catenin in MDPs was detected by immunocytochemistry using an anti‐β‐catenin antibody. D spp expression in MDPs was upregulated in the presence of BMP2 . W nt5a , W nt11 , L ef1 and T cf4 expression was upregulated in BMP2 ‐treated MDPs . W nt11 expression was detected in rat dental pulp in vivo , and particularly strong expression of W nt11 was detected in odontoblasts. Enhanced D spp and DMP1 expression and alkaline phosphatase activity induced by BMP2 were completely negated by the W nt antagonist: IWR ‐1‐endo treatment. Nuclear translocation of β‐catenin observed in BMP2 ‐treated MDPs was also negated by IWR ‐1‐endo treatment. These results indicate that W nt signaling upregulates odontoblast marker expression in MDPs , suggesting a promoting effect of Wnt signaling on odontoblast differentiation.