Wnt/β-Catenin Signaling Promotes the Formation of Preodontoblasts In Vitro

Abstract

Odontoblast differentiation is a complex and multistep process regulated by signaling pathways, including the Wnt/β-catenin signaling pathway. Both positive and negative effects of Wnt/β-catenin signaling on dentinogenesis have been reported, but the underlying mechanisms of these conflicting results are still unclear. To gain a better insight into the role of Wnt/β-catenin in dentinogenesis, we used dental pulp cells from a panel of transgenic mice, in which fluorescent protein expression identifies cells at different stages of odontoblast and osteoblast differentiation. Our results showed that exposure of pulp cells to WNT3a at various times and durations did not induce premature differentiation of odontoblasts. These treatments supported the survival of undifferentiated cells in dental pulp and promoted the formation of 2.3GFP+ preodontoblasts and their rapid transition into differentiated odontoblasts expressing DMP1-Cherry and DSPP-Cerulean transgenes. WNT3a also promoted osteogenesis in dental pulp cultures. These findings provide critical information for the development of improved treatments for vital pulp therapy and dentin regeneration.

6-Bromoindirubin-3′-Oxime Regulates Colony Formation, Apoptosis, and Odonto/Osteogenic Differentiation in Human Dental Pulp Stem Cells

“…In the present study, BIO treatment enhanced hDPSC osteogenic differentiation, as seen by increased ALP activity, odonto/osteogenic marker gene expression, and mineralised nodule formation. Similar results were found in other cell types, e.g., human PDLSCs [ 59 ], mouse PDLSCs [ 60 ], apical papilla stem cells [ 61 ], mouse DPs [ 62 ], hBMSCs [ 38 ], canine BMSCs [ 46 ], and mouse embryonic fibroblasts [ 63 ]. In contrast, it has been reported that LiCl-mediated Wnt signaling activation decreased the osteogenic differentiation [ 64 , 65 ].…”

Functional Dental Pulp Regeneration: Basic Research and Clinical Translation

“…It was proposed that Alx3 could promote parenchymal and stromal regeneration of tooth tissue by direct transactivation of the Wnt3a and VEGF promoters; thus, the Alx3/Wnt3a axis might represent a pivotal signalling pathway in the regeneration of pulpodentinal complex. Wnt3a was shown to direct and regulate the survival, migration, proliferation, and rapid differentiation of DPSCs [143][144][145]. After infusing recombinant human Wnt3a in collagen gel into clinically treated root canals of miniswine, the regeneration of vascularised pulp-like tissues and mineralised dentin-like structures was observed, probably through the recruitment of endogenous cells and promotion of cell survival in vivo [34].…”

Lithium Chloride Exerts Differential Effects on Dentinogenesis and Osteogenesis in Primary Pulp Cultures

“…These observations indicated that the positive effects of LiCl in the differentiation of osteoblasts and odontoblasts from αSMA + progenitors are mediated by Wnt/βcatenin signaling. The effects of LiCl on early progenitors is very similar to the effects of WNT3a (27).…”

“…The LiCl-induced decreases in the levels of Bsp during the mineralization phase of in vitro growth were not reversed by DKK1, indicating that the inhibitory effects of LiCl on osteogenesis and Bsp are not mediated through Wnt/β-catenin signaling. The inhibitory effects of prolonged exposure of pulp cells to LiCl are different from the stimulatory effects of WNT3a on pulp cells (27).…”

“…Primary pulp cultures were prepared from the coronal pulp of first and second molars from 5-to 7-d-old mice and grown as described in previous publications (26,27). The cultures were grown in the presence of vehicle (VH; 0.1% bovine serum albumin), various concentrations of LiCl (Sigma), and Dickkopf1 (DKK1) (R&D Systems), with or without simultaneous LiCl between days 3 and 21 (referred to as continuous exposure), days 7 and 21 (referred to as late exposure), and days 3 and 7 (referred to as early exposure).…”