Email updates

Keep up to date with the latest news and content from Arthritis Research & Therapy and BioMed Central.

This article is part of the supplement: 25th European Workshop for Rheumatology Research

Poster presentation

Resistance of rheumatoid arthritis synovial fibroblasts to p38 MAP-kinase inhibition of pro-destructive functions mediated by tumor necrosis factor alpha/tumor necrosis factor receptor-1

E Kunisch1, B Ukena1, R Fuhrmann2, A Roth2, R Winter2 and RW Kinne1

Author Affiliations

1 Experimental Rheumatology Unit, Friedrich Schiller University Jena, Germany

2 Clinic of Orthopedics, Friedrich Schiller University Jena, Germany

For all author emails, please log on.

Arthritis Research & Therapy 2005, 7(Suppl 1):P115  doi:10.1186/ar1636


The electronic version of this article is the complete one and can be found online at:


Received:11 January 2005
Published:17 February 2005

© 2005 BioMed Central Ltd

Objectives

In rheumatoid arthritis (RA), tumor necrosis factor (TNF) alpha is a major inductor of the proinflammatory/pro-destructive functions of synovial fibroblasts (SFB). These effects are predominantly mediated via the TNF receptor-1 (TNFR1). In addition to the NF-κB pathway, the p38 MAP kinase seems to play a central role for the underlying signal transduction. In the present study, RA-SFB were compared with osteoarthritis (OA)-SFB concerning the TNF-α/TNFR1/2-induced secretion of IL-6, IL-8, prostaglandin E2 (PGE2), and matrix metalloproteinase-1/tissue inhibitor of matrix metalloproteinase-1 (MMP-1/TIMP-1), as well as the sensitivity to p38 MAP-kinase inhibition.

Methods

Early-passage (second) RA-SFB and OA-SFB were analyzed for TNFR expression by FACS. The cells were then stimulated with TNF-α (10 ng/ml) or agonistic anti-TNFR1 (HTR-9) or anti-TNFR2 monoclonal antibodies (UTR-1; 10 μg/ml each) with/without inhibition of the p38 kinase by SB203580 (1 μM). Secretion of IL-6, IL-8, PGE2, MMP-1, and TIMP-1 was analyzed by ELISA.

Results

RA-SFB and OA-SFB both expressed TNFR1 and TNFR2 on their surface, without significant differences between the two groups. Secretion of IL-6, IL-8, PGE2, and MMP-1, but not TIMP-1, was significantly augmented by stimulation of RA-SFB and OA-SFB with TNF-α. Except for PGE2 (induced via both TNFRs), these effects were exclusively mediated via the TNFR1. Inhibition of p38 kinase reduced the secretion of IL-6 and PGE2 significantly and equally well in RA-SFB and OA-SFB. However, the secretion of MMP-1 was significantly suppressed only in OA-SFB, whereas RA-SFB were insensitive to the inhibition of MMP-1 secretion by p38 inhibition.

Conclusion

In early-passage RA-SFB and OA-SFB, TNF-α-induced proinflammatory/pro-destructive functions are predominantly mediated by TNFR1. Strikingly, RA-SFB are partially resistant to the suppression of pro-destructive MMP-1 by p38 MAP-kinase inhibition. The underlying structural or functional alterations of the p38 MAP kinase in RA-SFB may contribute to the pathogenesis and/or therapeutic sensitivity of RA.

Acknowledgements

This study was supported by the German Federal Ministry of Education and Research (BMBF; grant FKZ 01ZZ0105 to RWK, Interdisciplinary Center for Clinical Research Jena) and the German Research Foundation (DFG; grant KI 439/7-1 to RWK), as well as a grant for the advancement of female scientists to EK (LUBOM Thuringia).