title: Prostaglandin E2 inhibits in-vitro mineral deposition by human periodontal ligament cells via modulating the expression of TWIST1 and RUNX2.
abstract: OBJECTIVE
  Prostaglandin E2 (PGE2) has been shown to be able to influence both bone formation and resorption. The purpose of this study was to investigate the effect of PGE2 on the osteogenic differentiation of human periodontal ligament (HPDL) cells.
  
  
  METHODS
  HPDL cells were cultured with 0.001-1 μm PGE2 in osteogenic medium. In-vitro mineral deposition was determined by Alizarin Red S staining, and gene expression was determined by real-time PCR.
  
  
  RESULTS
  PGE2 inhibited in-vitro mineral deposition by HPDL cells in a dose-dependent manner. PCR analyses showed that PGE2 upregulated the expression of Runt-related transcription factor 2 (RUNX2), but had no effect on osteocalcin expression. Upregulation of TWIST-related protein1 (TWIST1), a functional antagonist of RUNX2, was also observed. In addition, increased levels of RUNX2 and TWIST1 proteins, induced by PGE2, were detected by western blot analysis. Using a chemical activator of E prostanoid (EP) receptors as well as small interfering RNA against an EP receptor, it was shown that PGE2 regulated RUNX2 and TWIST1 via the EP2 receptor. The role of protein kinase A in the inductive effect of PGE2 was also demonstrated.
  
  
  CONCLUSIONS
  The results of this study revealed that PGE2 modulates the osteogenic differentiation of HPDL cells via regulating the expression of RUNX2 and TWIST1. The results suggest a possible role for PGE2 in regulating the homeostasis of periodontal ligament tissue.
authors.affiliation: Mineralized Tissue Research Unit, Faculty of Dentistry, Chulalongkorn University, Bangkok, Thailand.
authors.forename: J
authors.initials: J
authors.lastname: Manokawinchoke
authors.forename: A
authors.initials: A
authors.lastname: Pimkhaokhum
authors.forename: V
authors.initials: V
authors.lastname: Everts
authors.forename: P
authors.initials: P
authors.lastname: Pavasant
mesh_terms: D000880:Anthraquinones; D018929:Cell Culture Techniques; D002454:Cell Differentiation / Q000187:drug effects; D002478:Cells, Cultured; D004396:Coloring Agents; D050659:Core Binding Factor Alpha 1 Subunit / Q000187:drug effects*; D017868:Cyclic AMP-Dependent Protein Kinases / Q000187:drug effects; D015232:Dinoprostone / Q000008:administration & dosage / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D005786:Gene Expression Regulation / Q000187:drug effects; D006706:Homeostasis / Q000187:drug effects; D006801:Humans; D009687:Nuclear Proteins / Q000187:drug effects*; D015675:Osteocalcin / Q000187:drug effects; D010012:Osteogenesis / Q000187:drug effects*; D010513:Periodontal Ligament / Q000166:cytology / Q000187:drug effects*; D016133:Polymerase Chain Reaction / Q000379:methods; D034741:RNA, Small Interfering / Q000235:genetics; D058307:Receptors, Prostaglandin E, EP2 Subtype / Q000819:agonists / Q000187:drug effects / Q000235:genetics; D051879:Twist-Related Protein 1 / Q000187:drug effects*; D015854:Up-Regulation
chemical_list: D000880:Anthraquinones; D004396:Coloring Agents; D050659:Core Binding Factor Alpha 1 Subunit; D009687:Nuclear Proteins; D034741:RNA, Small Interfering; C493709:RUNX2 protein, human; D058307:Receptors, Prostaglandin E, EP2 Subtype; C103173:TWIST1 protein, human; D051879:Twist-Related Protein 1; D015675:Osteocalcin; C004468:Alizarin Red S; D017868:Cyclic AMP-Dependent Protein Kinases; D015232:Dinoprostone
keywords: PGE2; RUNX2; TWIST1; human periodontal ligament cells; in-vitro mineral deposition