title: Laminin alpha2 is essential for odontoblast differentiation regulating dentin sialoprotein expression.
abstract: Laminin alpha2 is subunit of laminin-2 (alpha2beta1gamma1), which is a major component of the muscle basement membrane. Although the laminin alpha2 chain is expressed in the early stage of dental mesenchyme development and localized in the tooth germ basement membrane, its expression pattern in the late stage of tooth germ development and molecular roles are not clearly understood. We analyzed the role of laminin alpha2 in tooth development by using targeted mice with a disrupted lama2 gene. Laminin alpha2 is expressed in dental mesenchymal cells, especially in odontoblasts and during the maturation stage of ameloblasts, but not in the pre-secretory or secretory stages of ameloblasts. Lama2 mutant mice have thin dentin and a widely opened dentinal tube, as compared with wild-type and heterozygote mice, which is similar to the phenotype of dentinogenesis imperfecta. During dentin formation, the expression of dentin sialoprotein, a marker of odontoblast differentiation, was found to be decreased in odontoblasts from mutant mice. Furthermore, in primary cultures of dental mesenchymal cells, dentin matrix protein, and dentin sialophosphoprotein, mRNA expression was increased in laminin-2 coated dishes but not in those coated with other matrices, fibronectin, or type I collagen. Our results suggest that laminin alpha2 is essential for odontoblast differentiation and regulates the expression of dentin matrix proteins.
authors.affiliation: Division of Pediatric Dentistry, Department of Developmental and Reconstructive Medicine, Nagasaki University Graduate School of Biomedical Sciences, 1-7-1 Sakamoto, Nagasaki 852-8588, Japan.
authors.forename: Kenji
authors.initials: K
authors.lastname: Yuasa
authors.forename: Satoshi
authors.initials: S
authors.lastname: Fukumoto
authors.forename: Yoko
authors.initials: Y
authors.lastname: Kamasaki
authors.forename: Aya
authors.initials: A
authors.lastname: Yamada
authors.forename: Emiko
authors.initials: E
authors.lastname: Fukumoto
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Kanaoka
authors.forename: Kan
authors.initials: K
authors.lastname: Saito
authors.forename: Hidemitsu
authors.initials: H
authors.lastname: Harada
authors.forename: Eri
authors.initials: E
authors.lastname: Arikawa-Hirasawa
authors.forename: Yuko
authors.initials: Y
authors.lastname: Miyagoe-Suzuki
authors.forename: Shinichi
authors.initials: S
authors.lastname: Takeda
authors.forename: Kuniaki
authors.initials: K
authors.lastname: Okamoto
authors.forename: Yuzo
authors.initials: Y
authors.lastname: Kato
authors.forename: Taku
authors.initials: T
authors.lastname: Fujiwara
mesh_terms: D000818:Animals; D001485:Basement Membrane / Q000378:metabolism; D002448:Cell Adhesion; D002454:Cell Differentiation; D002455:Cell Division; D002478:Cells, Cultured; D003094:Collagen / Q000378:metabolism; D003743:Dental Enamel / Q000378:metabolism; D003804:Dentin / Q000378:metabolism; D016326:Extracellular Matrix Proteins; D005353:Fibronectins / Q000378:metabolism; D007150:Immunohistochemistry; D007797:Laminin / Q000378:metabolism / Q000502:physiology*; D051379:Mice; D008822:Mice, Transgenic; D008855:Microscopy, Electron, Scanning; D008856:Microscopy, Fluorescence; D009154:Mutation; D009804:Odontoblasts / Q000166:cytology* / Q000378:metabolism; D053495:Osteopontin; D010641:Phenotype; D010750:Phosphoproteins; D011485:Protein Binding; D011498:Protein Precursors; D012333:RNA, Messenger / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012795:Sialoglycoproteins / Q000096:biosynthesis*; D014070:Tooth / Q000196:embryology / Q000648:ultrastructure; D000099311:Dentin Sialophosphoprotein
chemical_list: D003094:Collagen; D016326:Extracellular Matrix Proteins; D005353:Fibronectins; D007797:Laminin; D053495:Osteopontin; D010750:Phosphoproteins; D011498:Protein Precursors; D012333:RNA, Messenger; D012795:Sialoglycoproteins; D000099311:Dentin Sialophosphoprotein; C506896:Spp1 protein, mouse; C102645:laminin alpha 2