title: Amelogenin enhances the proliferation of cementoblast lineage cells.
abstract: BACKGROUND
  It is well known that enamel matrix proteins play a crucial role in tooth root formation and amelogenesis. Because amelogenin is a major enamel matrix protein, it is assumed that amelogenin also affects the metabolism of cementum. However, the biologic functions of amelogenin in cementoblasts remain unclear. The purpose of this study is to examine the effect of recombinant human full-length amelogenin (rh174) on the proliferation of cultured human cementoblast-like (HCEM) and human periodontal ligament (HPDL) cells.
  
  
  METHODS
  HCEM and HPDL cells were cultured and treated with 100 ng/mL rh174 in the presence or absence of an anti-cluster of differentiation (CD) 63 blocking antibody. Cell proliferation was evaluated using a cell proliferation enzyme-linked immunosorbent assay 5-bromo-2-deoxyuridine kit and quantification of the cell number by 3-(4, 5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2 H-tetrazolium-inner salt assay. The phosphorylation of extracellular signal-regulated kinases (ERK) 1/2 was measured by enzyme-linked immunosorbent assay and Western blot analysis.
  
  
  RESULTS
  The proliferation of HCEM and HPDL cells was enhanced significantly (P <0.05) by treatment with rh174, and inhibited significantly (P <0.05) by the addition of anti-CD63 blocking antibody. In addition, the ratio of phosphorylated ERK1/2 to total ERK1/2 became significantly larger (P <0.05) by treatment with rh174, and was reduced significantly by the addition of anti-CD63 blocking antibody in both HCEM and HPDL cells.
  
  
  CONCLUSIONS
  The results show that rh174 interacts with CD63, and rh174/CD63 interaction activates the ERK1/2 signaling pathway, enhancing the proliferation activities of HCEM and HPDL cells.
authors.affiliation: Department of Orthodontics and Craniofacial Developmental Biology, Hiroshima University Graduate School of Biomedical Sciences, Hiroshima, Japan.
authors.forename: Ryo
authors.initials: R
authors.lastname: Kunimatsu
authors.forename: Kotaro
authors.initials: K
authors.lastname: Tanimoto
authors.forename: Yuki
authors.initials: Y
authors.lastname: Tanne
authors.forename: Takashi
authors.initials: T
authors.lastname: Kamiya
authors.forename: Satoru
authors.initials: S
authors.lastname: Ohkuma
authors.forename: Yu-Ching
authors.initials: YC
authors.lastname: Huang
authors.forename: Yuki
authors.initials: Y
authors.lastname: Yoshimi
authors.forename: Mutsumi
authors.initials: M
authors.lastname: Miyauchi
authors.forename: Takashi
authors.initials: T
authors.lastname: Takata
authors.forename: Kazuo
authors.initials: K
authors.lastname: Tanne
mesh_terms: D053523:Amelogenin / Q000378:metabolism*; D002460:Cell Line; D049109:Cell Proliferation; D003739:Dental Cementum / Q000166:cytology / Q000502:physiology*; D006801:Humans; D020935:MAP Kinase Signaling System / Q000502:physiology*; D010513:Periodontal Ligament / Q000166:cytology / Q000502:physiology*; D011994:Recombinant Proteins; D015398:Signal Transduction / Q000502:physiology; D060149:Tetraspanin 30 / Q000378:metabolism*
chemical_list: D053523:Amelogenin; D011994:Recombinant Proteins; D060149:Tetraspanin 30