title: Combined effects of simvastatin and enamel matrix derivative on odontoblastic differentiation of human dental pulp cells.
abstract: BACKGROUND
  We previously reported that simvastatin and enamel matrix derivative (EMD) have a dentinogenic effect. However, there is little information about the combined effects of these 2 agents on odontoblastic differentiation. The aim of this study was to investigate the effects of combined treatment with simvastatin and EMD on odontoblastic differentiation of human dental pulp cells (hDPCs). This study further explored the role of extracellular signal-regulated kinase (ERK) as a target and mediator of the differentiation induced by simvastatin in hDPCs.
  
  
  METHODS
  The odontoblastic differentiation was analyzed by alkaline phosphatase activity, real-time polymerase chain reaction (PCR) for odontoblastic/osteoblastic markers (ie, dentin sialophosphoprotein, dentin matrix protein 1, and osteonectin), and alizarin red S staining. We also explored the role of ERK signaling as a mediator of simvastatin by Western blotting and real-time PCR. The expression of osteoblast-specific transcription factors was detected by reverse-transcription PCR.
  
  
  RESULTS
  The alkaline phosphatase activity and the expression of odontoblastic markers (ie, dentin sialophosphoprotein and dentin matrix protein 1) increased in simvastatin/EMD-treated cells. Mineralized nodule formation increased in EMD- and simvastatin/EMD-treated cells. Notably, the combined use of both simvastatin and EMD resulted in more potent differentiation than that observed after a single therapy. Simvastatin activated ERK phosphorylation and treatment with ERK inhibitor blocked the messenger RNA expression of odontoblastic markers. However, in simvastatin/EMD-treated cells, the expression of these genes did not decrease significantly. Compared with other groups, the EMD- and simvastatin/EMD-treated group showed a greater expression of osterix.
  
  
  CONCLUSIONS
  Simvastatin promotes odontoblastic differentiation of hDPCs via the ERK signaling pathway. In addition, simvastatin-induced differentiation is facilitated by co-treatment with EMD. Collectively, these results suggest a new strategy to induce odontoblastic differentiation of hDPCs.
authors.affiliation: Department of Conservative Dentistry, Wonkwang University School of Dentistry, Iksan, Korea.
authors.forename: Lorena
authors.initials: L
authors.lastname: Karanxha
authors.forename: Su-Jung
authors.initials: SJ
authors.lastname: Park
authors.forename: Won-Jun
authors.initials: WJ
authors.lastname: Son
authors.forename: Jacques E
authors.initials: JE
authors.lastname: Nör
authors.forename: Kyung-San
authors.initials: KS
authors.lastname: Min
mesh_terms: D000469:Alkaline Phosphatase / Q000032:analysis; D000880:Anthraquinones; D002070:Butadienes / Q000494:pharmacology; D002113:Calcification, Physiologic / Q000187:drug effects; D018929:Cell Culture Techniques; D002454:Cell Differentiation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D004396:Coloring Agents; D050659:Core Binding Factor Alpha 1 Subunit / Q000032:analysis; D003746:Dental Enamel Proteins / Q000494:pharmacology*; D003782:Dental Pulp / Q000166:cytology / Q000187:drug effects*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D016326:Extracellular Matrix Proteins / Q000032:analysis; D048049:Extracellular Signal-Regulated MAP Kinases / Q000037:antagonists & inhibitors / Q000187:drug effects; D006801:Humans; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors / Q000494:pharmacology*; D020935:MAP Kinase Signaling System / Q000187:drug effects; D009570:Nitriles / Q000494:pharmacology; D009804:Odontoblasts / Q000187:drug effects*; D010006:Osteoblasts / Q000187:drug effects; D015676:Osteonectin / Q000032:analysis; D010750:Phosphoproteins / Q000032:analysis; D010766:Phosphorylation; D012795:Sialoglycoproteins / Q000032:analysis; D019821:Simvastatin / Q000494:pharmacology*; D000076182:Sp7 Transcription Factor; D014157:Transcription Factors / Q000032:analysis; D000099311:Dentin Sialophosphoprotein
chemical_list: D000469:Alkaline Phosphatase; D000880:Anthraquinones; D002070:Butadienes; D004396:Coloring Agents; D050659:Core Binding Factor Alpha 1 Subunit; D003746:Dental Enamel Proteins; D004791:Enzyme Inhibitors; D016326:Extracellular Matrix Proteins; D048049:Extracellular Signal-Regulated MAP Kinases; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors; D009570:Nitriles; D015676:Osteonectin; D010750:Phosphoproteins; D012795:Sialoglycoproteins; D019821:Simvastatin; D000076182:Sp7 Transcription Factor; D014157:Transcription Factors; D000099311:Dentin Sialophosphoprotein; C513309:DMP1 protein, human; C493709:RUNX2 protein, human; C478163:SP7 protein, human; C113580:U 0126; C109069:enamel matrix proteins; C004468:Alizarin Red S