Activation of dickkopf-1 and focal adhesion kinase pathway by tumour necrosis factor α induces enhanced migration of fibroblast-like synoviocytes in rheumatoid arthritis

Jung-Yoon Choe, Ji Hun Kim, Ki-Yeun Park, Chang-Hyuk Choi, Seong-Kyu Kim
2015 Rheumatology  
Objective. The objective of this study was to investigate the roles of dickkopf-1 (DKK-1) and integrinrelated focal adhesion kinase (FAK) by TNF-a on the migration of fibroblast-like synoviocytes (FLSs) in RA. Methods. Wound scratch assays were performed to assess FLS migration. Western blotting was used to measure the levels of DKK-1, Wnt signalling molecules and FAK signalling molecules. Quantitative realtime PCR was used to measure the expression levels of DKK-1, integrin av, laminin,
more » ... ctin, E-cadherin, MMP-8 and MMP-13. The concentrations of DKK-1, TNF-a and GSK-3b were measured by ELISA. Genetic silencing of TNF-a was achieved by the transfection of small interfering RNA into cells. Results. Migrating RA FLSs exhibited higher levels of DKK-1 and TNF-a expression compared with those in OA FLSs and/or stationary RA FLSs. Moreover, migrating FLSs exhibited significantly higher levels of FAK, p-JNK, paxillin and cdc42 expression, whereas the level of cytosolic b-catenin was lower. WAY-262611, Wnt pathway agonist via inhibition of DKK-1, markedly inhibited cell migration of RA FLSs through the accumulation of cytosolic b-catenin and suppression of FAK-related signalling pathways. TNF-a treatment to RA FLSs up-regulated expression of DKK-1, integrin av, fibronectin, laminin and MMP-13. TNF-a stimulation also suppressed cytosolic b-catenin and E-cadherin expression in a time-dependent manner. Moreover, TNF-a small interfering RNAtransfected migrating FLSs exhibited decreased activation of integrin-related FAK, paxillin, p-JNK and cdc42 signalling pathways. Conclusion. This study demonstrates that the activation of DKK-1 and the integrin-related FAK signalling pathway stimulated by TNF-a induces the dissociation of b-catenin/E-cadherin, thus promoting RA FLS migration. Key words: rheumatoid arthritis, dickkopf-1, fibroblast-like synoviocyte, migration, focal adhesion kinase, b-catenin, E-cadherin Rheumatology key messages . Enhanced expression of DKK-1 and FAK-related signal molecules was exhibited in migrating RA fibroblast-like synoviocytes (FLSs). . Dissociation of b-catenin and E-cadherin by DKK-1 is related with migration of RA FLSs. . Blocking of either DKK-1 or TNF-a might prevent migration of RA FLSs.
doi:10.1093/rheumatology/kev422 pmid:26715774 fatcat:hgdmkktr7ngd3cqy677t7vufse