title: FSL-1 induces MMP-9 production through TLR-2 and NF-κB /AP-1 signaling pathways in monocytic THP-1 cells.
abstract: BACKGROUND
  Matrix metalloproteinase-9 (MMP-9) is known to be implicated in the pathogenesis of many inflammatory disorders. FSL-1 (fibroblast-stimulating lipopeptide-1) induces cytokine production by monocytes/macrophages. However, it is unclear whether FSL-1 is also able to induce MMP-9 production. Herein, we determined whether FSL-1 could induce MMP-9 production, and if so, which signal transduction pathway(s) were involved.
  
  
  METHODS
  MMP-9 expression was assessed with real-time qPCR and ELISA. Signaling pathways were studied by using THP1-XBlue™ cells, THP1-XBlue™-defMyD cells, anti-TLR2 mAb and pharmacological inhibitors. Phospho and total proteins were determined by Western blotting.
  
  
  RESULTS
  FSL-1 induces MMP-9 expression (P<0.001) at both mRNA and protein levels in human monocytic THP-1 cells. Elevated activity (P<0.001) of NF-κB/AP-1 was also observed in FSL-1-treated THP-1 cells. FSL-1-induced MMP-9 secretion was markedly suppressed either by neutralizing anti-TLR-2 antibody or by inhibiting clathrin-dependent endocytosis. Furthermore, MyD88(-/-) THP-1 cells did not express MMP-9 in response to FSL-1 treatment. By small interfering RNA-mediated knockdown, we also show that FSL-1-induced up-regulation of MMP-9 requires MyD88. Pre-treatment of THP-1 cells with inhibitors of JNK (SP600125), MEK/ERK (U0126; PD98056; XMD 8-92), p38 MAPK (SB203580) and NF-κB (BAY11-7085, Triptolide, Resveratrol) significantly suppressed (P<0.05) MMP-9 gene expression and NF-κB/AP-1 transcription factors activity.
  
  
  CONCLUSIONS
  These findings provide the first evidence that FSL-1 induces TLR-2-dependent MMP-9 gene expression which requires the recruitment of MyD88 and leads to activation of MEK1/2 /ERK 1/2, MEK5/ERK5, JNK, p38 MAPK and NF-κB/AP-1.
authors.affiliation: Immunology & Innovative Cell therapy Unit, Dasman Diabetes Institute, Kuwait, Kuwait.
authors.forename: Rasheed
authors.initials: R
authors.lastname: Ahmad
authors.forename: Puthiyaveetil Kochumon
authors.initials: PK
authors.lastname: Shihab
authors.forename: Sara
authors.initials: S
authors.lastname: Jasem
authors.forename: Kazem
authors.initials: K
authors.lastname: Behbehani
mesh_terms: D015153:Blotting, Western; D002460:Cell Line; D004075:Diglycerides / Q000494:pharmacology*; D006801:Humans; D020780:Matrix Metalloproteinase 9 / Q000096:biosynthesis*; D016328:NF-kappa B / Q000378:metabolism*; D009842:Oligopeptides / Q000494:pharmacology*; D060888:Real-Time Polymerase Chain Reaction; D015398:Signal Transduction; D051195:Toll-Like Receptor 2 / Q000378:metabolism*; D018808:Transcription Factor AP-1 / Q000378:metabolism*
chemical_list: D004075:Diglycerides; C460864:FSL-1 lipoprotein, synthetic; D016328:NF-kappa B; D009842:Oligopeptides; C495342:TLR2 protein, human; D051195:Toll-Like Receptor 2; D018808:Transcription Factor AP-1; D020780:Matrix Metalloproteinase 9