Abstract | INTRODUCTION: METHODS: Expression of RasGRF1, MMP-1, MMP-3, and IL-6 was detected in synovial tissue by immunohistochemistry and stained sections were evaluated by digital image analysis. Expression of RasGRF1 in FLS and synovial tissue was also assessed by immunoblotting. Double staining was performed to detect proteins in specific cell populations, and cells producing MMP-1 and MMP-3. RasGRF1 expression was manipulated in RA FLS by cDNA transfection and gene silencing, and effects on MMP-1, TIMP-1, MMP-3, IL-6, and IL-8 production measured by ELISA. RESULTS: Expression of RasGRF1 was significantly enhanced in RA synovial tissue, and detected in FLS and synovial macrophages in situ. In cultured FLS and synovial biopsies, RasGRF1 was detected by immunoblotting as a truncated fragment lacking its negative regulatory domain. Production of MMP-1 and MMP-3 in RA but not non-RA synovial tissue positively correlated with expression of RasGRF1 and co-localized in cells expressing RasGRF1. RasGRF1 overexpression in FLS induced production of MMP-3, and RasGRF1 silencing inhibited spontaneous MMP-3 production. CONCLUSIONS: Enhanced expression and post-translational modification of RasGRF1 contributes to MMP-3 production in RA synovial tissue and the semi-transformed phenotype of RA FLS.
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Authors | Joana R F Abreu, Daphne de Launay, Marjolein E Sanders, Aleksander M Grabiec, Marleen G van de Sande, Paul P Tak, Kris A Reedquist |
Journal | Arthritis research & therapy
(Arthritis Res Ther)
Vol. 11
Issue 4
Pg. R121
( 2009)
ISSN: 1478-6362 [Electronic] England |
PMID | 19678938
(Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
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Chemical References |
- RASGRF1 protein, human
- ras-GRF1
- Matrix Metalloproteinase 3
- Matrix Metalloproteinase 1
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Topics |
- Adult
- Aged
- Arthritis, Rheumatoid
(metabolism)
- Blotting, Western
- Cells, Cultured
- Enzyme-Linked Immunosorbent Assay
- Female
- Fibroblasts
(metabolism)
- Fluorescent Antibody Technique
- Gene Expression
- Gene Expression Regulation
(physiology)
- Humans
- Image Processing, Computer-Assisted
- Immunohistochemistry
- Male
- Matrix Metalloproteinase 1
(biosynthesis)
- Matrix Metalloproteinase 3
(biosynthesis)
- Middle Aged
- Synovial Membrane
(metabolism)
- Transfection
- ras-GRF1
(genetics, metabolism)
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