title: Nephronectin Stimulates the Differentiation of MDPC-23 Cells into an Odontoblast-like Phenotype.
abstract: BACKGROUND
  The present study investigated the in vitro effects of nephronectin (Npnt) on the proliferation, differentiation, and mineralization of a rat odontoblast-like cell line (MDPC-23 cells).
  
  
  METHODS
  MDPC-23 cells were cultured on Npnt-coated polystyrene or in the presence of soluble Npnt. Cell proliferation was analyzed using a Cell Counting Kit-8 kit (Dojindo, Kumamoto, Japan). Alkaline phosphatase (ALP) activity was quantified using an ALP activity assay. A reverse-transcription polymerase chain reaction was performed to evaluate the messenger RNA (mRNA) expression level of odontogenic markers and integrin(s). Alizarin red staining was conducted to quantify the calcium deposition.
  
  
  RESULTS
  Soluble Npnt had no adverse effect on the proliferation of MDPC-23 cells, but it exhibited concentration-dependent inhibitory activity toward differentiation. In contrast, coated Npnt promoted cell proliferation dramatically and significantly up-regulated the mRNA expression of odontogenesis-related genes; moreover, mRNA expression of integrin α1, α3, α5, β1, and β5 was found to be augmented. MDPC-23 cells cultured on Npnt-coated polystyrene displayed markedly higher ALP activity as early as day 3 after inoculation. In addition, mineralization was accelerated on Npnt-coated polystyrene.
  
  
  CONCLUSIONS
  Npnt in its immobilized form enhanced the proliferation of MDPC-23 cells and induced this odontoblastic precursor cell line to differentiate into a mineralizing phenotype.
authors.affiliation: Division of Clinical Cariology, Department of Oral Rehabilitation, School of Dentistry, Health Sciences University of Hokkaido, Ishikari-Tobetsu, Hokkaido, Japan. Electronic address: tangjia@hoku-iryo-u.ac.jp.
authors.forename: Jia
authors.initials: J
authors.lastname: Tang
authors.affiliation: Division of Clinical Cariology, Department of Oral Rehabilitation, School of Dentistry, Health Sciences University of Hokkaido, Ishikari-Tobetsu, Hokkaido, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Saito
mesh_terms: D000469:Alkaline Phosphatase / Q000378:metabolism; D000818:Animals; D002454:Cell Differentiation / Q000187:drug effects*; D002460:Cell Line; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D016326:Extracellular Matrix Proteins / Q000494:pharmacology*; D009804:Odontoblasts / Q000187:drug effects*; D010641:Phenotype; D011137:Polystyrenes; D051381:Rats
chemical_list: D016326:Extracellular Matrix Proteins; D011137:Polystyrenes; C432915:nephronectin; D000469:Alkaline Phosphatase
keywords: Dentin; differentiation; nephronectin; odontoblast