Article
Rheumatoid arthritis synovial fibroblasts require distinct interaction with endothelial cells for long distance migration
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Authors
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Birgit Zimmermann
- Justus-Liebig Universität Gießen, Kerckhoff-Klinik GmbH, Rheumatologie u. klinische Immunologie, Osteologie, Physikalische Therapie, Bad Nauheim
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Sina Köppert
- Justus-Liebig Universität Gießen, Kerckhoff-Klinik GmbH, Rheumatologie u. klinische Immunologie, Osteologie, Physikalische Therapie, Bad Nauheim
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Stefan Rehart
- Agaplesion Markus Krankenhaus, Akademisches Lehrkrankenhaus der Johann Wolfgang Goethe-Universität, Klinik für Orthopädie und Unfallchirurgie, Frankfurt/Main
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Ulf Müller-Ladner
- Justus-Liebig Universität Gießen, Kerckhoff-Klinik GmbH, Rheumatologie u. klinische Immunologie, Osteologie, Physikalische Therapie, Bad Nauheim
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Elena Neumann
- Justus-Liebig Universität Gießen, Kerckhoff-Klinik GmbH, Rheumatologie u. klinische Immunologie, Osteologie, Physikalische Therapie, Bad Nauheim
| Published: | September 12, 2014 |
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Outline
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Background: Rheumatoid arthritis (RA) is a joint destructive disease and synovial fibroblasts (SF) are key players in that process. RASF long distance migration through the vasculature to distant cartilage could be observed in the SCID-mouse-model of RA. Up-regulated adhesion molecules on activated lymphocytes bind to their ligands on endothelial cells (EC), a process crucial for extravasation. The aim was to define molecules participating in the interaction between RASF and EC.
Methods: Immunostainings: Double-staining for CD15s (E-selectin ligand) and vimentin (fibroblasts) in RA and osteoarthritis (OA) synovium; CD15s staining on serum-stimulated RA-/OASF. Laminar flow assay: Quantification of adhering and tethering RA- and OASF under dynamic conditions towards E-/P-selectins or TNF-treated (10ng/ml) HUVEC (aHUVEC) or untreated HUVEC on capillary slides. Sialidase digestion of RASF for 30 min was used to reduce selectin-ligands on RASF. Cell-to-cell binding assay: Static adhesion of RA-/OASF incubated with RPMI/DMEM for 15min on aHUVEC- or HUVEC-monolayers.
Results: 12/12 RA and 1/7 OA tissues were CD15s-positive, CD15s was co-localized with vimentin in 67% of the RA (50% in the sublining, 25% in vessels, 25% in both compartments) but not in OA tissues. RA- but not healthy serum induced CD15s in cultured RASF (80%, n=5) and OASF (33%, n=3). RASF adhesion to E-selectin-coated capillaries was significantly higher than to P-selectin (e.g. 18.4ml/h: E-selectin=15.3±2.5, P-selectin=1.5±1.5; n=4). RASF adhered to E-selectin significantly stronger than OASF (n=3; e.g. 18.4ml/h: E-selectin=2.1±0.2). RASF-adhesion to aHUVEC was significantly increased (18.4ml/h: RASF 9.7±1.3, OASF 2.1±0.4, n=3). Sialidase (n=2) reduced RASF dynamic adhesion to E-/P-selectin. Static adhesion (n=3) was significantly increased for RASF in RPMI (aHUVEC-RPMI: 122.1±10.3; HUVEC-RPMI: 78.2±7.3; aHUVEC-DMEM: 77.1±6.5; HUVEC-DMEM: 58.7±5.9). OASF showed reduced adhesion than RASF (aHUVEC-RPMI: 55.0±3.1; HUVEC-RPMI: 47.2±5.1; aHUVEC-DMEM: 62.2±2.9; HUVEC-DMEM: 50.3±3.4).
Conclusion: The data show an increased adhesion of RASF compared to OASF under static and dynamic conditions, most likely based on CD15 expression and subsequent EC interaction. Thus, the RASF-specific ability to express CD15s and interact with EC most likely facilitates the crucial interaction of RASF with the vascular system. Other adhesion molecules, beside selectins, which are known to be increased in RASF, likely participate also to this interaction.
