Calcium-mediated increased expression of fibroblast growth factor-2 acts through NF-κB and PGE2/EP4 receptor signaling pathways in cementoblasts

Sousuke Kanaya, Eiji Nemoto, Yukihiko Sakisaka, Hidetoshi Shimauchi

Research output: Contribution to journalArticlepeer-review

13 Citations (Scopus)

Abstract

We reported previously that cementoblasts are provided with sensing mechanisms for extracellular Ca2+ and that elevated extracellular Ca2+ increases fibroblast growth factor-2 (FGF-2) gene and protein expression levels via a cyclic AMP/protein kinase A (PKA) dependent pathway. In the present study, we found that stimulation of murine cementoblasts with 10mM CaCl2 induced cyclooxygenase-2 (COX-2) gene expression and prostaglandin E2 (PGE2) biosynthesis. NS-398, a COX-2 inhibitor, significantly reduced CaCl2-induced increase in Fgf-2 gene expression, indicating that PGE2 synthesized by COX-2 may be involved in FGF-2 induction. The inhibitory effect of NS-398 was restored completely by the addition of PGE2 receptor 4 (E-prostanoid receptor 4, called EP4) agonist, but not agonists for EP1, EP2, and EP3. Furthermore, EP4 antagonist significantly reduced CaCl2-induced Fgf-2 induction, suggesting that it is mediated by EP4 activation. However, stimulation with EP4 agonist alone in the absence of CaCl2 had no effect on the Fgf-2 induction, indicating that EP4 signaling alone is not sufficient. CaCl2 also upregulated gene expression levels of Ep4 and Cox-2, as well as Fgf-2 and induction of these genes was abolished by pretreatment with BMS-345541, a nuclear factor-κB (NF-κB) inhibitor, indicating that NF-κB signaling triggered by CaCl2 is indispensable for FGF-2 induction. Furthermore, CaCl2-induced Fgf-2 induction was synergistically enhanced by the addition of EP4 agonist. This indicates that the signaling triggered via CaCl2 and its combination with EP4 agonist may be useful as a novel strategy for periodontal regeneration.

Original languageEnglish
Pages (from-to)398-405
Number of pages8
JournalBone
Volume56
Issue number2
DOIs
Publication statusPublished - 2013 Oct

Keywords

  • COX-2
  • Cementoblast
  • Extracellular Ca
  • FGF-2
  • PGE

ASJC Scopus subject areas

  • Endocrinology, Diabetes and Metabolism
  • Physiology
  • Histology

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