title: Activation of dickkopf-1 and focal adhesion kinase pathway by tumour necrosis factor α induces enhanced migration of fibroblast-like synoviocytes in rheumatoid arthritis.
abstract: OBJECTIVE
  The objective of this study was to investigate the roles of dickkopf-1 (DKK-1) and integrin-related focal adhesion kinase (FAK) by TNF-α 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 real-time PCR was used to measure the expression levels of DKK-1, integrin αv, laminin, fibronectin, E-cadherin, MMP-8 and MMP-13. The concentrations of DKK-1, TNF-α and GSK-3β were measured by ELISA. Genetic silencing of TNF-α was achieved by the transfection of small interfering RNA into cells.
  
  
  RESULTS
  Migrating RA FLSs exhibited higher levels of DKK-1 and TNF-α 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 β-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 β-catenin and suppression of FAK-related signalling pathways. TNF-α treatment to RA FLSs up-regulated expression of DKK-1, integrin αv, fibronectin, laminin and MMP-13. TNF-α stimulation also suppressed cytosolic β-catenin and E-cadherin expression in a time-dependent manner. Moreover, TNF-α small interfering RNA-transfected migrating FLSs exhibited decreased activation of integrin-related FAK, paxillin, p-JNK and cdc42 signalling pathways.
  
  
  CONCLUSIONS
  This study demonstrates that the activation of DKK-1 and the integrin-related FAK signalling pathway stimulated by TNF-α induces the dissociation of β-catenin/E-cadherin, thus promoting RA FLS migration.
authors.affiliation: Division of Rheumatology, Department of Internal Medicine, Catholic University of Daegu School of Medicine, Arthritis and Autoimmunity Research Center, Catholic University of Daegu, Daegu.
authors.forename: Jung-Yoon
authors.initials: JY
authors.lastname: Choe
authors.affiliation: Department of Rheumatology, Pohang Semyung Christianity Hospital, Pohang and.
authors.forename: Ji
authors.initials: J
authors.lastname: Hun Kim
authors.affiliation: Arthritis and Autoimmunity Research Center, Catholic University of Daegu, Daegu.
authors.forename: Ki-Yeun
authors.initials: KY
authors.lastname: Park
authors.affiliation: Department of Orthopedic Surgery, Catholic University of Daegu School of Medicine, Daegu, Republic of Korea.
authors.forename: Chang-Hyuk
authors.initials: CH
authors.lastname: Choi
authors.affiliation: Division of Rheumatology, Department of Internal Medicine, Catholic University of Daegu School of Medicine, Arthritis and Autoimmunity Research Center, Catholic University of Daegu, Daegu, kimsk714@cu.ac.kr.
authors.forename: Seong-Kyu
authors.initials: SK
authors.lastname: Kim
mesh_terms: D000368:Aged; D001172:Arthritis, Rheumatoid / Q000378:metabolism / Q000473:pathology*; D015820:Cadherins / Q000378:metabolism; D002465:Cell Movement / Q000502:physiology; D002478:Cells, Cultured; D005260:Female; D005347:Fibroblasts / Q000502:physiology; D051417:Focal Adhesion Kinase 1 / Q000235:genetics / Q000502:physiology*; D020868:Gene Silencing; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins / Q000235:genetics / Q000502:physiology*; D008875:Middle Aged; D010003:Osteoarthritis / Q000378:metabolism / Q000473:pathology; D034741:RNA, Small Interfering / Q000235:genetics; D015398:Signal Transduction / Q000502:physiology; D013583:Synovial Membrane / Q000473:pathology*; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics / Q000502:physiology*; D051176:beta Catenin / Q000378:metabolism
chemical_list: C495270:CTNNB1 protein, human; D015820:Cadherins; C501126:DKK1 protein, human; D036341:Intercellular Signaling Peptides and Proteins; D034741:RNA, Small Interfering; D014409:Tumor Necrosis Factor-alpha; D051176:beta Catenin; D051417:Focal Adhesion Kinase 1; C496050:PTK2 protein, human
keywords: E-cadherin; dickkopf-1; fibroblast-like synoviocyte; focal adhesion kinase; migration; rheumatoid arthritis; β-catenin