Activation of Wnt signaling in Axin2+ cells leads to osteodentin formation and cementum overgrowth

Abstract Objectives In this study, we used the mouse incisor model to investigate the regulatory mechanisms of Wnt/β‐catenin signaling on Axin2 + cells in tooth development. Materials and Methods Axin2 lacZ/+ reporter mice were used to define the expression pattern of Axin2 in mouse incisors. We traced the fate of Axin2 + cells from postnatal Day 21 (P21) to P56 using Axin2 CreERT2/+ and R26R tdTomato/+ reporter mice. For constitutive activation of Wnt signaling, Axin2 CreERT2/+ , β‐catenin flox(Ex3)/+ , and R26R tdTomato/+ (CA‐β‐cat) mice were generated to investigate the gain of function (GOF) of β‐catenin in mouse incisor growth. Results The X‐gal staining of Axin2 lacZ/+ reporter mice and lineage tracing showed that Axin2 was widely expressed in dental mesenchyme of mouse incisors, and Axin2 + cells were essential cell sources for odontoblasts, pulp cells, and periodontal ligament cells. The constitutive activation of Wnt signaling in Axin2 + cells resulted in the formation of osteodentin featured with increased DMP1 and dispersed DSP expression and overgrowth of cementum. Conclusion Wnt signaling plays a key role in the differentiation and maturation of Axin2 + cells in mouse incisors.