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Signaling mechanism of thrombin‐induced gingival fibroblast‐populated collagen gel contraction
Author(s) -
Jeng JiiangHuei,
Lan WanHong,
Wang JuoSong,
Chan ChiuPo,
Ho YuanSoon,
Lee PoHsuen,
Wang YingJen,
Wang TongMei,
Chen YiJane,
Chang MeiChi
Publication year - 2006
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1038/sj.bjp.0706462
Subject(s) - thrombin , chemistry , wortmannin , endocrinology , biochemistry , pharmacology , medicine , kinase , phosphatidylinositol , biology , platelet
Thrombin is activated during gingival tissue injury and inflammation. Thrombin (platelet)‐rich plasma has been used for periodontal regeneration with success. Thrombin and other bacterial proteases also affect the functions of adjacent periodontal cells via stimulation of protease‐activated receptors (PARs). We noted that thrombin (0.1–2 U ml −1 ), human, and frog PAR‐1 agonist peptide (20–240 μ M ) induced the gingival fibroblast (GF)‐populated collagen gel contraction within 2 h of exposure. However, PAR‐2, PAR‐3, and PAR‐4 agonist peptide (20–240 μ M ) showed little effect on collagen gel contraction. U73122 (phospholipase C inhibitor) and 2‐APB (IP3 antagonist) were effective in inhibition of GF contraction. Thrombin‐induced GF contraction was inhibited by 5 m M EGTA (an extracellular calcium chelator) and verapamil (an L‐type calcium channel blocker). In addition, W7 (10 and 25 μ M , a calcium/calmodulin (CaM) inhibitor), ML‐7 (50 μ M , myosin light chain kinase (MLCK) inhibitor), and HA1077 (100 μ M , Rho kinase inhibitor) completely inhibited the thrombin‐induced collagen gel contraction. Thrombin also induced the phosphorylation of ERK1/ERK2 and elevated the Rho‐GTP levels in GF. However, U0126 only partially inhibited the thrombin‐induced GF contraction. Similarly, wortmannin (100 n M ), LY294002 (20 μ M ) (two PI3K inhibitor) and genistein also showed partial inhibition. Moreover, NAC was not able to suppress the GF contraction, as supported by the slight decrease in reactive oxygen species production in GF by thrombin. Thrombin also stimulated metalloproteinase‐2 (MMP‐2) and MMP‐3 production in GF. But addition of GM6001 or 1,10‐phenanthroline, two MMP inhibitors, could not inhibit the thrombin‐induced GF contraction. These results indicate that thrombin is crucial in the periodontal inflammation and wound healing by promoting GF contraction. This event is mainly mediated via PAR‐1 activation, PLC activation, extracellular calcium influx via L‐type calcium channel, and the calcium/CaM–MLCK and Rho kinase activation pathway.British Journal of Pharmacology (2006) 147 , 188–198. doi: 10.1038/sj.bjp.0706462