| Abstract: |
Objective. It is not understood why cultured fibroblast-like synoviocytes (FLS) from patients with rheumatoid arthritis (RA) often display a persistently activated phenotype, despite removal from an inflammatory environment. Previously, we found that these FLS expressed high levels of both Wnt-5A and Frizzled 5 (Fz5), a receptor-ligand pair implicated in both limb bud and bone marrow stem cell development. The objective of the present experiments was to determine whether Wnt-5A/Fz5 signaling contributes to FLS activation. Methods. Wnt-5A expression in FLS was inhibited by transfection with both antisense and dominant negative (dn) vectors. Fz5 signaling was blocked with an antibody to the extracellular domain of the receptor. The effects of these treatments on the expression of the proinflammatory cytokines interleukin-6 (IL-6) and IL-15 and on the expression of receptor activator of nuclear factor κB ligand (RANKL) were assessed by reverse transcriptase-polymerase chain reaction and immunoblotting. Results. Both antisense Wnt-5A and dnWnt-5A vectors, but not empty vector, diminished IL-6 and IL-15 expression in RA FLS. Anti-Fz5 antibody exerted similar effects and also reduced RANKL expression. Conclusion. Wnt-5A/Fz5 signaling, may contribute to the activated state of FLS in RA. Receptor antagonists of Fz5 should be considered for the treatment of refractory synovitis. |
| Keywords: |
signal transduction; protein expression; proto-oncogene proteins; nonhuman; cells, cultured; reverse transcription polymerase chain reaction; gene expression; dna, antisense; immunoglobulin enhancer binding protein; transfection; enzyme linked immunosorbent assay; hybrid protein; reverse transcriptase polymerase chain reaction; rna, messenger; membrane glycoproteins; arthritis; carrier proteins; ligand; glutathione transferase; immunoblotting; interleukin 6; interleukin-6; fibroblasts; rheumatoid arthritis; enzyme-linked immunosorbent assay; wnt proteins; wnt protein; receptors, g-protein-coupled; interleukin 15; complementary dna; rank ligand; antibodies, blocking; frizzled receptors; interleukin-15; synovial membrane; synoviocyte; synovitis; arthritis, rheumatoid; receptor activator of nuclear factor-kappa b; humans; human; priority journal; article; receptors, neurotransmitter
|
