Increased phosphorylation of ezrin is associated with the migration and invasion of fibroblast-like synoviocytes from patients with rheumatoid arthritis

Rheumatology (Oxford). 2014 Jul;53(7):1291-300. doi: 10.1093/rheumatology/keu013. Epub 2014 Mar 4.


Objective: Increasing evidence indicates that the cytoskeletal protein ezrin may play a critical role in cell motility. This study aims to investigate the role of ezrin in regulating the migration and invasion of fibroblast-like synoviocytes (FLSs) from patients with RA.

Methods: Synovial tissues were obtained from 12 patients with RA and 6 with OA, and then FLSs were separated from synovial tissues. The expression of ezrin and phosphorylated ezrin (p-ezrin) was examined by Western blotting or IF staining. A specific inhibitor of ezrin phosphorylation and small interference RNA-mediated ezrin knockdown were used to inhibit the phosphorylation of ezrin. Migration and invasion of FLSs in vitro were measured by the Boyden chamber assay.

Results: Increased expression of p-ezrin protein was found in synovial tissue and FLSs in patients with RA compared with patients with OA. Stimulation with TNF-α and IL-1β increased ezrin phosphorylation in RA FLSs. Inhibition of p-ezrin protein by a specific inhibitor of phosphorylation of ezrin and small interfering RNA-mediated knockdown reduced in vitro migration and invasion, as well as actin stress fibre formation in RA FLS. Furthermore, rho kinase and p38 mitogen-activated protein kinase (MAPK) signal pathways were involved in the phosphorylation of ezrin and invasion of RA FLSs.

Conclusion: Increased expression of p-ezrin may contribute to aberrant aggressive behaviours of RA FLSs, which are mediated by rho kinase and the p38 MAPK pathway. This suggests a novel strategy targeting phosphorylation of ezrin to prevent synovial invasiveness and joint destruction in RA.

Keywords: ezrin; fibroblast-like synoviocytes; invasion; phosphorylation; rheumatoid arthritis; signal transduction.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Arthritis, Rheumatoid / metabolism*
  • Arthritis, Rheumatoid / pathology*
  • Cell Movement / drug effects
  • Cell Movement / physiology*
  • Cells, Cultured
  • Cytoskeletal Proteins / metabolism*
  • Female
  • Fibroblasts / drug effects
  • Fibroblasts / metabolism
  • Fibroblasts / pathology*
  • Humans
  • In Vitro Techniques
  • Interleukin-1beta / pharmacology
  • Male
  • Middle Aged
  • Phosphorylation / drug effects
  • Phosphorylation / physiology
  • RNA, Small Interfering / pharmacology
  • Signal Transduction / drug effects
  • Signal Transduction / physiology
  • Synovial Membrane / drug effects
  • Synovial Membrane / metabolism
  • Synovial Membrane / pathology*
  • Tumor Necrosis Factor-alpha / pharmacology
  • p38 Mitogen-Activated Protein Kinases / metabolism
  • rho-Associated Kinases / metabolism


  • Cytoskeletal Proteins
  • Interleukin-1beta
  • RNA, Small Interfering
  • Tumor Necrosis Factor-alpha
  • ezrin
  • rho-Associated Kinases
  • p38 Mitogen-Activated Protein Kinases