TNF-α stimulates MMP-3 production via PGE2 signalling through the NF-kB and p38 MAPK pathway in a murine cementoblast cell line

Background: Cementoblasts are considered to play an important role in the homeostasis of periodontal tissues under both physiologic and pathologic conditions. Matrix metalloproteinases (MMPs) is the key family of enzymes participating in extracellular matrix remodelling. In the present study, the effects and regulatory mechanisms of tumour necrosis factor (TNF)-alpha on the expression of MMPs and their inhibitors (tissue inhibitor of metalloproteinases; TIMPs) were investigated. Materials and methods: OCCM-30, an immortalised murine cementoblast cell line, was stimulated with TNF-alpha at 1 and 10 ng/ml for 24 h. The expression of Mmp-2, Mmp-3, Mmp-13, Mmp-14, Timp-1, and Timp-2 as well as PGE(2) was determined. Inhibitors of MAPKs, PI3K/Akt, NF-kB and Cox-2 were employed to reveal possible TNF-alpha induced regulatory signalling pathway(s). The mRNA and protein expression were analysed by (semi)quantitative real-time PCR and enzyme-linked immunosorbent assay (ELISA), respectively. Results: TNF-alpha dose-dependently stimulated MMP-3 expression by cementoblasts. This was found for mRNA as well as protein expression. No significant differences were found in the mrtNA expression of Mmp-2, Mmp-13, Mmp-14, Timp-1, and Timp-2 upon TNF-alpha stimulation. The level of PGE(2), however, was significantly increased along with MMP-3. Treatment with a selective Cox-2 inhibitor resulted in partial suppression of TNF-alpha-induced Mmp-3 mRNA expression. Addition of PGE(2) enhanced Mmp-3 mRNA in a dose dependent manner, suggesting an inductive effect of TNF-alpha partly via PGE(2). The up-regulation of Mmp-3 by TNF-alpha was completely suppressed by a combination of NF-kB and p38 MAPK inhibitors, while partial suppression was found with each inhibitor. The effect of PGE(2) on Mmp-3 expression was abolished by treating cells with an NF-kB inhibitor; a p38 MAPK inhibitor had only a small effect. Conclusions: The present study indicates that cementoblasts respond to TNF-alpha by increasing MMP-3 production partially via PGE(2) and signalling through the NF-kB and p38 MAPK pathway. MMP-3 may participate in periodontal tissue degradation/remodelling. (C) 2015 Elsevier Ltd. All rights reserved.