Volume 9 Supplement 3

6thGlobal Arthritis Research Network (GARN) Meeting

Open Access

Activation of synovial fibroblasts by laminin-1 and transforming growth factor beta induces expression of stromelysins independently of TNFα, IL-1β or NF-κB

  • Katrin Warstat1,
  • Thomas Pap2,
  • Gerd Klein3,
  • Steffen Gay4 and
  • Wilhelm K Aicher1
Arthritis Research & Therapy20079(Suppl 3):P17

DOI: 10.1186/ar2243

Published: 19 October 2007

Recently it was shown that attachment of synovial fibroblasts (SF) from rheumatoid arthritis patients to laminin-111 (LM-111) induced an elevated expression of stromelysin-1 (MMP-3). We therefore investigated the regulation of additional matrix metalloproteinases (MMPs) and their specific tissue inhibitors of matrix metalloproteinases (TIMPs) by attachment to LM-111 in the presence of transforming growth factor beta (TGFβ). Changes in steady-state mRNA levels encoding TIMPs and MMPs were investigated by quantitative RT-PCR. Production of MMPs and cytokines was monitored by a multiplexed immunoarray or by ELISA. Signal transduction pathways were studied by immunoblotting. Attachment of SF to LM-111 in the presence of TGFβ induced significant increases in stromelysin-1 mRNA (12.35-fold, P < 0.001) and protein (mean 62 ng/ml, sixfold, P < 0.008). Expression of stromelysin-2 (MMP-10) mRNA (11.68-fold, P < 0.05) and protein (54 ng/ml, 20-fold, P ≥ 0.02) was significantly activated as well. All other TIMPs and MMPs investigated failed to show this LM-111-facilitated TGFβ response. Induction of stromelysin-1 and stromelysin-2 was associated with the activation of transcription factors c-fos and Egr-1, but phosphorylation of NF-κB was not observed. Further, LM-111-activated and TGFβ-activated SF failed to produce remarkable amounts of IL-1β or TNFα. We conclude that costimulation of synovial fibroblasts by LM-111 together with TGFβ suffices to induce significant expression of MMP-3 and MMP-10 by SF and that this induction is independent of phosphorylation of NF-κB.

Authors’ Affiliations

(1)
Center for Medical Research (ZMF), Department of Orthopedic Surgery, Eberhard-Karls-University Medical School
(2)
Division of Molecular Medicine of Musculoskeletal Tissue, Department of Orthopedics, Münster University Hospital
(3)
Center for Medical Research (ZMF), Section for Transplantation Immunology, University of Tübingen
(4)
WHO Center for Experimental Rheumatology, University Hospital Zürich

Copyright

© BioMed Central Ltd 2007

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