title: Dentin matrix protein-1 activates dental pulp fibroblasts.
abstract: BACKGROUND
  Dentin matrix protein-1 (DMP-1) is involved in the mineralization of hard dental tissues. DMP-1 is localized in several soft tissues, but its role is unclear.
  
  
  METHODS
  Human inflamed dental pulps were collected from the endodontic clinic and human normal pulps from impacted teeth. Dental pulp cells from 8 subjects were explanted to test the effect of DMP-1 on interleukin-6 (IL-6) and IL-8 production by using enzyme-linked immunosorbent assay.
  
  
  RESULTS
  DMP-1 was localized in pulp inflammation by using immunohistochemistry but was not present in impacted root pulps. Wherever found, areas of calcification were positively stained against DMP-1, suggesting its possible involvement in pulp inflammation and in pathologic calcification. To test this hypothesis, primary human pulp fibroblasts were cultured. The fibroblasts were identified on the basis of their morphology, immunoreactivity against vimentin and collagen 1a1 by immunofluorescence and negative staining to CD45, CD34, and cytokeratin by flow cytometry. DMP-1 (10 ng/mL) stimulated the production of IL-6 and IL-8 from pulp fibroblasts. DMP-1 showed an additive effect with lipopolysaccharide in IL-6 and IL-8 production. Inhibition of the p38 mitogen-activated protein kinase pathway blocked the proinflammatory effect of DMP-1 on pulp fibroblasts.
  
  
  CONCLUSIONS
  Our data indicate that DMP-1 might participate in the development of inflammatory changes in the dental pulp. DMP-1 inhibition might be a new therapeutic strategy to target pulp inflammation and pathologic calcification.
authors.affiliation: Department of Dentistry, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada.
authors.forename: Ashraf
authors.initials: A
authors.lastname: Abd-Elmeguid
authors.forename: Donald C
authors.initials: DC
authors.lastname: Yu
authors.forename: Loren W
authors.initials: LW
authors.lastname: Kline
authors.forename: Redwan
authors.initials: R
authors.lastname: Moqbel
authors.forename: Harissios
authors.initials: H
authors.lastname: Vliagoftis
mesh_terms: D002114:Calcinosis / Q000473:pathology; D018929:Cell Culture Techniques; D003782:Dental Pulp / Q000166:cytology* / Q000276:immunology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D016326:Extracellular Matrix Proteins / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D005347:Fibroblasts / Q000187:drug effects* / Q000276:immunology; D006801:Humans; D007093:Imidazoles / Q000494:pharmacology; D018836:Inflammation Mediators / Q000037:antagonists & inhibitors; D015850:Interleukin-6 / Q000032:analysis; D016209:Interleukin-8 / Q000187:drug effects; D008070:Lipopolysaccharides / Q000494:pharmacology; D020935:MAP Kinase Signaling System / Q000187:drug effects; D010750:Phosphoproteins / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D011671:Pulpitis / Q000473:pathology; D011725:Pyridines / Q000494:pharmacology; D014095:Tooth, Impacted / Q000473:pathology; D048051:p38 Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors
chemical_list: C513309:DMP1 protein, human; D004791:Enzyme Inhibitors; D016326:Extracellular Matrix Proteins; D007093:Imidazoles; D018836:Inflammation Mediators; D015850:Interleukin-6; D016209:Interleukin-8; D008070:Lipopolysaccharides; D010750:Phosphoproteins; D011725:Pyridines; D048051:p38 Mitogen-Activated Protein Kinases; C093642:SB 203580