Interleukin-21 receptor deficiency increases the initial toll-like receptor 2 response but protects against joint pathology by reducing Th1 and Th17 cells during streptococcal cell wall arthritis

Renoud J. Marijnissen, Debbie M. Roeleveld, Deborah Young, Cheryl Nickerson-Nutter, Shahla Abdollahi-Roodsaz, Sabrina Garcia de Aquino, Fons A. J. van de Loo, Annemiek B. van Spriel, Annemieke M. H. Boots, Wim B. van den Berg, Marije I. Koenders*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

26 Citations (Scopus)

Abstract

OBJECTIVE: The cytokine interleukin-21 (IL-21) can have both proinflammatory and immunosuppressive effects. The purpose of this study was to investigate the potential dual role of IL-21 in experimental arthritis in relation to Th17 cells.

METHODS: Antigen-induced arthritis (AIA) and chronic streptococcal cell wall (SCW) arthritis were induced in IL-21 receptor-deficient (IL-21R(-/-) ) and wild-type mice. Knee joints, synovial tissue, and serum were analyzed for arthritis pathology and inflammatory markers.

RESULTS: During AIA and chronic SCW arthritis, IL-21R deficiency protected against severe inflammation and joint destruction. This was accompanied by suppressed serum IgG1 levels and antigen-specific T cell responses. Levels of IL-17 were reduced during AIA, and synovial lymphocytes isolated during SCW arthritis for flow cytometry demonstrated that mainly IL-17+ interferon-γ (IFNγ)-positive T cells were reduced in IL-21R(-/-) mice. However, during the acute phases of SCW arthritis, significantly higher joint swelling scores were observed, consistent with enhanced tumor necrosis factor and IL-6 expression. Interestingly, IL-21R(-/-) mice were significantly less capable of up-regulating suppressor of cytokine signaling 1 (SOCS-1) and SOCS-3 messenger RNA. IL-21 stimulation also affected the Toll-like receptor 2 (TLR-2)/caspase recruitment domain 15 response to SCW fragments in vitro, indicating that impaired SOCS regulation in the absence of IL-21 signaling might contribute to the increased local activation during SCW arthritis.

CONCLUSION: In contrast to the proinflammatory role of IL-21 in adaptive immunity, which drives IL-17+IFN+ cells and joint pathology during chronic experimental arthritis, IL-21 also has an important immunosuppressive role, presumably by inhibiting TLR signaling via SOCS-1 and SOCS-3. If this dual role of IL-21 in various immune processes is present in human disease, it could make IL-21 a difficult therapeutic target in rheumatoid arthritis.

Original languageEnglish
Pages (from-to)886-895
Number of pages10
JournalArthritis & Rheumatology
Volume66
Issue number4
DOIs
Publication statusPublished - Apr-2014

Keywords

  • RHEUMATOID-ARTHRITIS
  • MURINE ARTHRITIS
  • T(H)17 CELLS
  • IL-21
  • ACTIVATION
  • DIFFERENTIATION
  • INFLAMMATION
  • GENERATION
  • EXPANSION
  • PATHWAY

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