Artikel
Focal adhesion proteins kindlin-1, -2 and talin-1 are downregulated in IL-1β activated rheumatoid arthritis synovial fibroblasts
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Autoren
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Mona Arnold
- Justus-Liebig-University, Campus Kerckhoff, Department of Rheumatology and Clinical Immunology, Bad Nauheim
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Stefan Rehart
- Agaplesion Markus Hospital, Department of Orthopaedics and Trauma Surgery, Frankfurt am Main
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Michael Sauerbier
- Private Practice for Hand and Plastic Surgery, Bad Homburg v. d. Hoehe
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Christoph Biehl
- University Hospital of Giessen-Marburg, Dept. of Trauma, Hand and Reconstructive Surgery, Giessen
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Ulf Müller-Ladner
- Justus-Liebig-University, Campus Kerckhoff, Department of Rheumatology and Clinical Immunology, Bad Nauheim
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Elena Neumann
- Justus-Liebig-University, Campus Kerckhoff, Department of Rheumatology and Clinical Immunology, Bad Nauheim
| Veröffentlicht: | 31. August 2022 |
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Gliederung
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Introduction: Rheumatoid arthritis (RA) is a progressive chronic inflammatory disease characterized by activated synovial fibroblasts (SF) resulting in excessive joint erosion. The kindlin family of focal adhesion proteins consists of three members whose function is to activate integrins. The consequences of this activation are cell adhesion, migration and proliferation, all of which are known to be pathologically increased in RASF. It is well described that kindlin-1,-2,-3 and their co-factor talin-1 are involved in the pathogenesis of certain diseases. However, the role of kindlins and talin-1 in RA, and specifically RASF, remain unclear.
Objective: To investigate the cellular and compartmental localisation of kindlins and talin-1 in RA synovial tissue and RASF, and the impact of pro-inflammatory stimulation on their expression on mRNA and protein level
Methods: RASF were isolated from synovial tissue after joint replacement surgery. RASF were stimulated with 10 ng/ml IL-1β for 6 h,17 h,24 h and 48 h. RNA was isolated and qPCR performed for kindlins-1,-2,-3 and talin-1. Immunocytochemistry on RASF seeded on chamber slides was performed. Immunohistochemistry on synovial tissue was performed on 5 µm acetone-fixed cryosections. Kruskal-Wallis-test with Dunn’s multiple comparison was used for statistics.
Results: Kindlin-2 and talin-1 were expressed adjacent to blood vessels, in the synovial lining layer and sublining of RA synovial tissues and on RASF. Relative mRNA levels (arbitrary units) of kindlins and talin-1 in RASF were different, with talin-1 (663.1±186.2), followed by kindlin-2 (88.9±23.2), kindlin-1 (2.15±2.06) and kindlin-3 (0.12±0.08). In comparison to unstimulated controls, IL-1β led to a downregulation of kindlin-2 (-4.1-fold, p=0.0456) and talin-1 (-1.6-fold) after 17 h and returned to the baseline mRNA levels after 48 h. This effect could also be observed in immunocytochemistry of RASF. Kindlin-1 mRNA expression was significantly upregulated after 6 h (2.9-fold, p=0.0178) of stimulation and downregulated after 17 h (-1.5-fold, p<0.0001), 24 h (-0.7-fold, p=0.0004) and 48 h (-1.2-fold, p<0.0001).
Conclusion: Kindlins and talin-1, factors involved in integrin activation of cells, are present on RASF. As a time-dependent regulation of kindlins after stimulation was observed, this effect may lead to a temporary activation of RASF and activation of integrins, subsequently contributing to altered adhesion and migration of RASF under inflammatory arthritic conditions.
