title: Transforming growth factor β1 down-regulates Runx-2 and alkaline phosphatase activity of human dental pulp cells via ALK5/Smad2/3 signaling.
abstract: OBJECTIVE
  Transforming growth factor β1 (TGF-β1) plays a role in repair and dentinogenesis in dental pulp. The purpose of this study was to study how TGF-β1 affects 2 differentiation markers, Runt-related transcription factor 2 (Runx-2) and ALP, in dental pulp cells.
  
  
  METHODS
  Primary-cultured human dental pulp cells were treated with TGF-β1 with or without pretreatment and coincubation with 1,4-diamino-2,3-dicyano-1,4-bis(o-aminophenylmercapto)butadiene (U0126, a mitogen-induced extracellular kinase (MEK)/extracellular signal-regulated kinase (ERK) inhibitor), Noggin (a bone morphogenetic protein inhibitor), or 4-(5-benzol[1,3]dioxol-5-yl-4-pyrldin-2-yl-1H-imidazol-2-yl)-benzamide hydrate (SB431542, an activin receptor-like kinase (ALK) 5/Smad2/3 inhibitor). The differentiation status of pulp cells was evaluated by ALP staining and quantitative ALP activity assay. Changes in ALP and Runx-2 mRNA expression were determined by reverse-transcription polymerase chain reaction.
  
  
  RESULTS
  Cells under the treatment of TGF-β1 (5 and 10 ng/mL) showed a decrease in ALP activity and gene expression of ALP and Runx-2. Pretreatment by U0126 and Noggin was not effective to prevent the TGF-β1-induced decline of ALP activity. Interestingly, SB431542 prevented the TGF-β1-induced decline of ALP activity and ALP and Runx-2 gene expression.
  
  
  CONCLUSIONS
  TGF-β1 down-regulates Runx-2 and ALP in human dental pulp cells via ALK5/Smad2/3 signaling. These events may play important roles at specific stages of pulpal repair and dentinogenesis.
authors.affiliation: Department of Dentistry/School of Dentistry, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, Taiwan.
authors.forename: Po-Shuen
authors.initials: PS
authors.lastname: Lin
authors.forename: Mei-Chi
authors.initials: MC
authors.lastname: Chang
authors.forename: Chiu-Po
authors.initials: CP
authors.lastname: Chan
authors.forename: Sheng-Yang
authors.initials: SY
authors.lastname: Lee
authors.forename: Jang-Jaer
authors.initials: JJ
authors.lastname: Lee
authors.forename: Yi-Ling
authors.initials: YL
authors.lastname: Tsai
authors.forename: Hui-Chun
authors.initials: HC
authors.lastname: Tseng
authors.forename: Tseng-Fang
authors.initials: TF
authors.lastname: Tai
authors.forename: Hsueh-Jen
authors.initials: HJ
authors.lastname: Lin
authors.forename: Jiiang-Huei
authors.initials: JH
authors.lastname: Jeng
mesh_terms: D000469:Alkaline Phosphatase / Q000037:antagonists & inhibitors / Q000378:metabolism*; D001549:Benzamides / Q000494:pharmacology; D019485:Bone Morphogenetic Proteins / Q000037:antagonists & inhibitors; D002070:Butadienes / Q000494:pharmacology; D002352:Carrier Proteins / Q000494:pharmacology; D002478:Cells, Cultured; D050659:Core Binding Factor Alpha 1 Subunit / Q000037:antagonists & inhibitors / Q000378:metabolism*; D003782:Dental Pulp / Q000166:cytology / Q000201:enzymology / Q000378:metabolism*; D004149:Dioxoles / Q000494:pharmacology; D015536:Down-Regulation / Q000502:physiology*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006801:Humans; D020929:Mitogen-Activated Protein Kinase Kinases / Q000037:antagonists & inhibitors; D009570:Nitriles / Q000494:pharmacology; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D000077293:Receptor, Transforming Growth Factor-beta Type I; D018125:Receptors, Transforming Growth Factor beta / Q000037:antagonists & inhibitors / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology*; D051899:Smad2 Protein / Q000037:antagonists & inhibitors / Q000378:metabolism*; D051900:Smad3 Protein / Q000037:antagonists & inhibitors / Q000378:metabolism*; D053773:Transforming Growth Factor beta1 / Q000378:metabolism* / Q000494:pharmacology; D000099176:Noggin Protein
chemical_list: D000469:Alkaline Phosphatase; D001549:Benzamides; D019485:Bone Morphogenetic Proteins; D002070:Butadienes; D002352:Carrier Proteins; D050659:Core Binding Factor Alpha 1 Subunit; D004149:Dioxoles; D004791:Enzyme Inhibitors; D020929:Mitogen-Activated Protein Kinase Kinases; D009570:Nitriles; D017346:Protein Serine-Threonine Kinases; D000077293:Receptor, Transforming Growth Factor-beta Type I; D018125:Receptors, Transforming Growth Factor beta; D051899:Smad2 Protein; D051900:Smad3 Protein; D053773:Transforming Growth Factor beta1; D000099176:Noggin Protein; C459179:4-(5-benzo(1,3)dioxol-5-yl-4-pyridin-2-yl-1H-imidazol-2-yl)benzamide; C493709:RUNX2 protein, human; C497782:SMAD2 protein, human; C497790:SMAD3 protein, human; C113580:U 0126; C000625841:TGFBR1 protein, human