Cell dynamics in Hertwig's epithelial root sheath are regulated by β-catenin activity during tooth root development

beta-catenin, a key mediator of Wnt signaling, plays multiple roles in tooth development. However, the role of beta-catenin in Hertwig's epithelial root sheath (HERS) during root formation remains unclear. In this study, we generated inducible tissue-specific beta-catenin conditional knockout mice (Ctnnb1(i increment shh)) to investigate how beta-catenin in HERS affects tooth root development. The inactivation of beta-catenin in HERS led to interrupted root elongation due to premature disruption of HERS. This phenotype was accompanied by reduced cell-cell adhesion and decreased expression of junctional proteins, as well as increased epithelial-to-mesenchymal transition of HERS cells upon beta-catenin depletion. Accordingly, stabilization of beta-catenin in HERS (Catnb(i increment shh)) led to the formation of unfragmented HERS and resulted in the failure of HERS dissociation, with increased expression of junctional proteins. Our results suggest that fine control of beta-catenin is important for HERS to guide root formation through regulating its structural integrity.

Automated summary

Fine control of beta-catenin is crucial for Hertwig's epithelial root sheath (HERS) integrity and junctional protein expression, which play pivotal roles in tooth root formation. Stabilization of beta-catenin promotes unfragmented HERS formation and prevents HERS dissociation, while its destabilization leads to premature disruption of HERS and interrupted root elongation.