title: CpG ODN-induced matrix metalloproteinase-13 expression is mediated via activation of the ERK and NF-κB signalling pathways in odontoblast cells.
abstract: OBJECTIVE
  To investigate the effects of CpG ODN (CpG oligodeoxynucleotides) to model the action of bacterial challenge on pulpal matrix metalloproteinase-13 (MMP-13) expression and elucidate the associated intracellular signalling pathways.
  
  
  METHODS
  Real-time PCR was used to detect the effects of CpG ODN on MMP-13 mRNA expression levels in a murine odontoblast-lineage cell line (OLCs). The possible involvement of TLR9/MyD88, NF-κB or MAPK pathways involved in the CpG ODN-induced MMP-13 expression was examined by real-time PCR, transient transfection, luciferase activity assay and ELISA. Western blotting was performed to assay the phosphorylation of ERK at a range of time points.
  
  
  RESULTS
  MMP-13 was constitutively expressed in OLCs, and their exposure to CpG ODN significantly increased MMP-13 expression. Pre-treatment of OLCs with the inhibitory peptide MyD88, or chloroquine, attenuated the CpG ODN-induced expression of MMP-13. Treatment of the OLCs with CpG ODN increased NF-κB-luciferase activity. This activity was decreased by the over-expression of a nondegrading mutant of IκBα (IκBαSR), although enhanced by the over-expression of NF-κB p65. MMP-13 expression induced by CpG ODN was markedly suppressed by NF-κB inhibitors (pyrrolidine dithiocarbamate, PDTC), IκBα phosphorylation inhibitors (Bay 117082) or IκB protease inhibitor (L-1-tosylamido-2-phenylethyl chloromethyl ketone, TPCK). The inhibitor of ERK1/2, U0126, but not inhibitors of p38 MAPK and JNK, SB203580 and SP600125, decreased CpG ODN-mediated MMP-13 expression.
  
  
  CONCLUSIONS
  The CpG ODN-induced MMP-13 expression in OLCs is mediated through TLR9, NF-κB and the ERK pathway indicating that potentially the recognition of CpG ODN by TLR9 on odontoblasts may regulate the remodelling of injured dental pulp and hard tissues by inducing MMP-13 expression.
authors: Department of Operative Dentistry & Endodontics, School of Stomatology, Fourth Military Medical University, Xi'an, China.
authors: J
authors: J
authors: Zhang
authors: Q L
authors: QL
authors: Zhu
authors: P
authors: P
authors: Huang
authors: Q
authors: Q
authors: Yu
authors: Z H
authors: ZH
authors: Wang
authors: P R
authors: PR
authors: Cooper
authors: A J
authors: AJ
authors: Smith
authors: W
authors: W
authors: He
mesh_terms: D000818:Animals; D000873:Anthracenes / Q000494:pharmacology; D002460:Cell Line; D002738:Chloroquine / Q000494:pharmacology; D018899:CpG Islands; D003782:Dental Pulp / Q000187:drug effects / Q000201:enzymology*; D048049:Extracellular Signal-Regulated MAP Kinases / Q000187:drug effects; D020672:I-kappa B Proteins / Q000494:pharmacology; D007093:Imidazoles / Q000494:pharmacology; D020935:MAP Kinase Signaling System / Q000187:drug effects; D053509:Matrix Metalloproteinase 13 / Q000187:drug effects*; D051379:Mice; D020928:Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors; D053594:Myeloid Differentiation Factor 88 / Q000494:pharmacology; D016328:NF-kappa B / Q000037:antagonists & inhibitors / Q000187:drug effects; D009570:Nitriles / Q000494:pharmacology; D009804:Odontoblasts / Q000187:drug effects / Q000201:enzymology; D009838:Oligodeoxyribonucleotides / Q000494:pharmacology*; D010766:Phosphorylation; D011725:Pyridines / Q000494:pharmacology; D011759:Pyrrolidines / Q000494:pharmacology; D060888:Real-Time Polymerase Chain Reaction; D015398:Signal Transduction / Q000187:drug effects; D013450:Sulfones / Q000494:pharmacology; D013859:Thiocarbamates / Q000494:pharmacology; D051217:Toll-Like Receptor 9 / Q000187:drug effects; D014108:Tosylphenylalanyl Chloromethyl Ketone / Q000494:pharmacology; D051996:Transcription Factor RelA / Q000494:pharmacology
chemical_list: C434003:3-(4-methylphenylsulfonyl)-2-propenenitrile; D000873:Anthracenes; C408982:CPG-oligonucleotide; C083487:I kappa B beta protein; D020672:I-kappa B Proteins; D007093:Imidazoles; C507780:Myd88 protein, mouse; D053594:Myeloid Differentiation Factor 88; D016328:NF-kappa B; D009570:Nitriles; D009838:Oligodeoxyribonucleotides; D011725:Pyridines; D011759:Pyrrolidines; C498144:Rela protein, mouse; D013450:Sulfones; D013859:Thiocarbamates; C495370:Tlr9 protein, mouse; D051217:Toll-Like Receptor 9; D051996:Transcription Factor RelA; C432165:pyrazolanthrone; C020972:pyrrolidine dithiocarbamic acid; D014108:Tosylphenylalanyl Chloromethyl Ketone; D002738:Chloroquine; D048049:Extracellular Signal-Regulated MAP Kinases; D020928:Mitogen-Activated Protein Kinases; D053509:Matrix Metalloproteinase 13; C507081:Mmp13 protein, mouse; C093642:SB 203580