title: Requirement of Smad4-mediated signaling in odontoblast differentiation and dentin matrix formation.
abstract: Dentin is the major part of tooth and formed by odontoblasts. Under the influence of the inner enamel epithelium, odontoblasts differentiate from ectomesenchymal cells of the dental papilla and secrete pre-dentin which then undergo mineralization into dentin. Transforming growth factor-beta (TGF-β)/bone morphogenetic protein (BMP) signaling is essential for dentinogenesis; however, the precise molecular mechanisms remain unclear. To understand the role of TGF-β/BMP signaling in odontoblast differentiation and dentin formation, we generated mice with conditional ablation of Smad4, a key intracellular mediator of TGF-β/BMP signaling, usingOsr2orOC-Cremice. Here we found the molars ofOsr2CreSmad4mutant mice exhibited impaired odontoblast differentiation, and normal dentin was replaced by ectopic bone-like structure. InOsr2CreSmad4mutant mice, cell polarity of odontoblast was lost, and the thickness of crown dentin was decreased in later stage compared to wild type. Moreover, the root dentin was also impaired and showed ectopic bone-like structure similar toOsr2CreSmad4mutant mice. Taken together, our results suggest that Smad4-dependent TGF-β/BMP signaling plays a critical role in odontoblast differentiation and dentin formation during tooth development.
authors.affiliation: Cluster for Craniofacial Development and Regeneration Research, Institute of Oral Biosciences, Chonbuk National University School of Dentistry, Jeonju, Korea.
authors.forename: Chi-Young
authors.initials: CY
authors.lastname: Yun
authors.affiliation: Cluster for Craniofacial Development and Regeneration Research, Institute of Oral Biosciences, Chonbuk National University School of Dentistry, Jeonju, Korea.
authors.forename: Hwajung
authors.initials: H
authors.lastname: Choi
authors.affiliation: Cluster for Craniofacial Development and Regeneration Research, Institute of Oral Biosciences, Chonbuk National University School of Dentistry, Jeonju, Korea.
authors.forename: Young-Jae
authors.initials: YJ
authors.lastname: You
authors.affiliation: Department of Dental Hygiene, Daejeon Institute of Science and Technology, Daejeon, Korea.
authors.forename: Jin-Young
authors.initials: JY
authors.lastname: Yang
authors.affiliation: Cluster for Craniofacial Development and Regeneration Research, Institute of Oral Biosciences, Chonbuk National University School of Dentistry, Jeonju, Korea.
authors.forename: Jin-A
authors.initials: JA
authors.lastname: Baek
authors.affiliation: Cluster for Craniofacial Development and Regeneration Research, Institute of Oral Biosciences, Chonbuk National University School of Dentistry, Jeonju, Korea.
authors.forename: Eui-Sic
authors.initials: ES
authors.lastname: Cho
keywords: Dentin; Odontoblasts; Smad4; TGF-β/BMP signaling