ACTIVATION OF DICKKOPF-1 AND FOCAL ADHESION KINASE PATHWAY BY TUMOR NECROSIS FACTOR-ALPHA ENHANCED MIGRATION OF FIBROBLAST-LIKE SYNOVIOCYTES IN RHEUMATOID ARTHRITIS

Background: The migration of fibroblast-like synoviocytes (FLS) has been recognized as a unique feature in rheumatoid arthritis (RA). Objectives: This study investigated the role of dickkopf-1 (DKK-1) and integrin-related focal adhesion kinase (FAK) on the cell migration of fibroblast-like synoviocytes (FLS) through the regulation of β-catenin in RA. Methods: The activation of migration were preformed by wound scratching assays. The expression of Wnt/β-catenin and FAK signaling molecules was determined by western blot. Expression of integrin αv, laminin, fibronectin, E-cadherin, integrins, MMP-8, and MMP-13 was measured by real-time quantitative RT-PCR. The DKK-1 morphology was observed by fluorescence microscopy. The inhibitory effects of TNF-α were employed by small interfering RNA transfection into cells. Results: More enhanced DKK-1 and TNF-α expression in migrating RA FLS were noted than those in OA FLS and/or stationary FLS. Migrating FLS induced FAK, p-JNK, paxillin, and cdc42 expression, but attenuated cytosolic β-catenin expression. WAY-262611 markedly inhibited cell migration in RA FLS through accumulation of cytosolic β-catenin and suppression of FAK-related signaling pathway. TNF-α enhanced DKK-1, integrin αv, fibronectin, laminin, and MMP-13 expression, which were markedly reduced by WAY-262611 treated with FLS. Increased expression of integrin-related FAK and its downstream molecules such as paxillin, JNK, and cdc42 in migrating FLS was suppressed by blocking TNF-α using RLS trasnfected with siRNA TNF-α. TNF-α suppressed cytosolic β-catenin and E-cadherin expression in time-dependent manner. Conclusions: This study demonstrated that enhanced expression of DKK-1 and activation of integrin-related FAK signal pathway stimulated by TNF-α induced dissociation of β-catenin and E-cadherin, then resulting in promotion of RA FLS migration. References: 1. Neumann E, et al. Trends Mol Med 2010;16:458-68. 2. Müller-Ladner U, et al. Am J Pathol 1996;149:1607-15. 3. Cadigan KM, et al. Genes Dev 1997;11:3286-305. 4. Koch S, et al. Mol Biol Cell 2009;20:4816-25. 5. Kuang HB, et al. Front Biosci 2009;14:2212-20. Disclosure of Interest: None declared DOI: 10.1136/annrheumdis-2015-eular.4317Citation: Annals of the Rheumatic Diseases, volume 74, supplement 2, year 2015, page 937Session: Rheumatoid arthritis - etiology, pathogenesis and animal models (Abstracts Accepted for Publication )