125. Roles of Wnt/-catenin signaling in tooth root formation

Speaker : Eui-Sic Cho, (Chonbuk National University School of Dentistry,, Korea)

Location : Room 512 Dental building, Dankook University 

Date: 2022-06-10

 

Roles of Wnt/β-catenin signaling in tooth root formation

Abstract

Laboratory for Craniofacial Biology, Institute of Oral Bioscience

Chonbuk National University School of Dentistry, Jeonju 54896, Korea

Wnt/β-catenin signaling plays multiple roles in both dental epithelium and mesenchyme

during various stages of tooth development. Previously, we reported that Wnt/β-catenin

signaling is essential in dental mesenchyme for tooth root formation and cementum

apposition. However, it remains unknown whether Wnt/β-catenin signaling is required in

Hertwig’s epithelial root sheath (HERS), essential for tooth root formation. To address the

contribution of Wnt/β-catenin signaling in HERS during root development, we analyzed

mice with inducible β-catenin disruption or stabilization allele in HERS. Following the

disruption of β-catenin induced by tamoxifen administration, HERS was prematurely

dissociated in the developing root apex and further root elongation was impaired. In contrast,

HERS dissociation was failed after root dentin formation and it covered the root dentin

surface following the induction of β-catenin stabilization. Moreover, neither acellular

cementum nor cementoblasts were observed and mineralization of the neighboring root

dentin was severely impaired. These results indicate that Wnt/β-catenin signaling is

necessary to maintain cellular integrity of HERS until completion of root formation, and that

excessive Wnt/β-catenin signaling disturbs HERS dissociation after root dentin formation

and leads to impaired acellular cementum formation and dentin mineralization. Taken

together, it is suggested that Wnt/β-catenin signaling plays an essential role in root and

cementum formation through the fate determination of HERS. These findings may provide

new insight to understand molecular and cellular events underlying root and cementum

formation.