title: Stratum intermedium lineage diverges from ameloblast lineage via Notch signaling.
abstract: The stratum intermedium develops as flattened cell layers on the proximal side of the ameloblast layer during tooth development. However, little information is available regarding the origin and the role. In this study, we indicate that some stratum intermedium cells originate from the inner enamel epithelium (IEE) in rat incisor organ cultures using DiI as a tracer. Immunohistochemical and in situ hybridization studies showed that the stratum intermedium cells express the Notch1 protein and Hes1 mRNAs, while the IEE and ameloblasts express the Jagged1. Further, we examined the role of Notch signaling using the dental epithelial cell line HAT-7. Recombinant Jagged1 protein enhanced the appearance of stratum intermedium cells in HAT-7 cultures and neutralization with an anti-Jagged1 antibody inhibited these effects. Additionally, overexpression of the Notch1 internal domain increased the number of stratum intermedium cells. We hypothesize that the stratum intermedium lineage differentiates from the ameloblast lineage via Notch signaling.
authors.affiliation: Department of Oral Anatomy and Developmental Biology, Osaka University Graduate School of Dentistry, 1-8, Yamadaoka, Suita, Osaka 565-0871, Japan. hide-h@dent.osaka-u.ac.jp
authors.forename: Hidemitsu
authors.initials: H
authors.lastname: Harada
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Ichimori
authors.forename: Tamaki
authors.initials: T
authors.lastname: Yokohama-Tamaki
authors.forename: Hayato
authors.initials: H
authors.lastname: Ohshima
authors.forename: Shintaro
authors.initials: S
authors.lastname: Kawano
authors.forename: Ken-ichi
authors.initials: K
authors.lastname: Katsube
authors.forename: Satoshi
authors.initials: S
authors.lastname: Wakisaka
mesh_terms: D000565:Ameloblasts / Q000166:cytology* / Q000502:physiology*; D000818:Animals; D002135:Calcium-Binding Proteins / Q000378:metabolism / Q000502:physiology; D002450:Cell Communication / Q000502:physiology; D002454:Cell Differentiation / Q000502:physiology*; D002460:Cell Line; D019070:Cell Lineage / Q000502:physiology*; D003743:Dental Enamel / Q000166:cytology / Q000254:growth & development / Q000502:physiology; D007180:Incisor; D036341:Intercellular Signaling Peptides and Proteins; D000072100:Jagged-1 Protein; D008565:Membrane Proteins / Q000378:metabolism / Q000502:physiology; D009924:Organ Culture Techniques; D051381:Rats; D017207:Rats, Sprague-Dawley; D051880:Receptors, Notch / Q000502:physiology*; D000072099:Serrate-Jagged Proteins; D015398:Signal Transduction / Q000502:physiology*
chemical_list: D002135:Calcium-Binding Proteins; D036341:Intercellular Signaling Peptides and Proteins; C000606275:Jag1 protein, rat; D000072100:Jagged-1 Protein; D008565:Membrane Proteins; D051880:Receptors, Notch; D000072099:Serrate-Jagged Proteins