title: Effects of heparin-binding epidermal growth factor-like growth factor on cell repopulation and signal transduction in periodontal ligament cells after scratch wounding in vitro.
abstract: OBJECTIVE
  A growing amount of attention has been placed on periodontal regeneration and wound healing for periodontal therapy. This study was conducted in an effort to determine the effects of heparin-binding epidermal growth factor-like growth factor on cell repopulation and signal transduction in periodontal ligament cells after scratch wounding in vitro.
  
  
  METHODS
  Human periodontal ligament cells were acquired from explant tissue of human healthy periodontal ligament. After the wounding of periodontal ligament cells, the change in expression of heparin-binding epidermal growth factor-like growth factor and epidermal growth factor receptors 1-4 mRNA was assessed. The effects of heparin-binding epidermal growth factor-like growth factor on periodontal ligament cell proliferation and repopulation were assessed in vitro via the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and by photographing the injuries, respectively. Extracellular signal-regulated kinase (Erk)1/2, p38 and Akt phosphorylation was characterized via western blotting.
  
  
  RESULTS
  Scratch wounding resulted in a significant up-regulation of heparin-binding epidermal growth factor-like growth factor mRNA expression, whereas wounding had no effect on the expression levels of epidermal growth factor receptors 1-4. Interestingly, no expression of epidermal growth factor receptors 2 and 4 was detectable prior to or after wounding. Heparin-binding epidermal growth factor-like growth factor treatment promoted the proliferation and repopulation of periodontal ligament cells. The scratch wounding also stimulated the phosphorylation of Erk1/2 and p38, but not of Akt, in periodontal ligament cells, and heparin-binding epidermal growth factor-like growth factor treatment applied after wounding amplified and extended the activations of Erk1/2 and p38, but not of Akt. Furthermore, Erk1/2 inhibition blocked the process of cell repopulation induced by heparin-binding epidermal growth factor-like growth factor, whereas the inhibition of p38 delayed the process.
  
  
  CONCLUSIONS
  These results indicate that heparin-binding epidermal growth factor-like growth factor may constitute a critical factor in the wound healing of human periodontal ligament cells by a mechanism that requires the activation of Erk1/2 via specific interaction with epidermal growth factor receptor 1.
authors.affiliation: Department of Oral Biology, BK21 project, Oral Science Research Center, Yonsei University College of Dentistry, Seoul, Korea.
authors.forename: J S
authors.initials: JS
authors.lastname: Lee
authors.forename: J M
authors.initials: JM
authors.lastname: Kim
authors.forename: E K
authors.initials: EK
authors.lastname: Hong
authors.forename: S-O
authors.initials: SO
authors.lastname: Kim
authors.forename: Y-J
authors.initials: YJ
authors.lastname: Yoo
authors.forename: J-H
authors.initials: JH
authors.lastname: Cha
mesh_terms: D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D004396:Coloring Agents; D004789:Enzyme Activation / Q000502:physiology; D066246:ErbB Receptors / Q000032:analysis; D006493:Heparin / Q000032:analysis / Q000502:physiology*; D066257:Heparin-binding EGF-like Growth Factor; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins / Q000032:analysis / Q000502:physiology*; D019950:Mitogen-Activated Protein Kinase 1 / Q000032:analysis; D048052:Mitogen-Activated Protein Kinase 3 / Q000032:analysis; D010513:Periodontal Ligament / Q000293:injuries* / Q000473:pathology; D010766:Phosphorylation / Q000502:physiology; D051057:Proto-Oncogene Proteins c-akt / Q000032:analysis; D011956:Receptors, Cell Surface / Q000032:analysis / Q000502:physiology*; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology*; D013778:Tetrazolium Salts; D013844:Thiazoles; D014945:Wound Healing / Q000187:drug effects / Q000502:physiology; D048051:p38 Mitogen-Activated Protein Kinases / Q000032:analysis
chemical_list: D004396:Coloring Agents; C587883:HBEGF protein, human; D066257:Heparin-binding EGF-like Growth Factor; D036341:Intercellular Signaling Peptides and Proteins; D011956:Receptors, Cell Surface; D013778:Tetrazolium Salts; D013844:Thiazoles; D006493:Heparin; D066246:ErbB Receptors; D051057:Proto-Oncogene Proteins c-akt; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D048051:p38 Mitogen-Activated Protein Kinases; C022616:thiazolyl blue