Cyclosporine differentially regulates interleukin-10, interleukin-15, and tumor necrosis factor a production by rheumatoid synoviocytes

Abstract

Objective: To determine the direct effect of cyclosporin A (CSA) on the production of cytokines by rheumatoid synovial fibroblasts.

Methods: Fibroblast-like synoviocytes (FLS) were prepared from the synovial tissues of patients with rheumatoid arthritis and cultured in the presence of CSA. The production of interleukin-10 (IL-10), IL-15, and tumor necrosis factor a (TNFalpha) by FLS was measured in culture supernatants by enzyme-linked immunosorbent assay. The expression of IL-10, IL-15, and TNFalpha messenger RNA (mRNA) in FLS was determined by polymerase chain reaction (PCR).

Results: CSA (1-1,000 ng/ml) increased the production of IL-10, but decreased in a dose-dependent manner the levels of IL-15 and TNFalpha that were spontaneously secreted from FLS. CSA also potently inhibited the production of IL-15 and TNFalpha stimulated with interferon-gamma, IL-1beta, or lipopolysaccharide. The inhibitory effect of CSA on IL-15 and TNFalpha production depended on the increase in IL-10, since neutralizing anti-IL-10 antibodies were able to partially reverse this inhibition. In a semiquantitative PCR, CSA increased IL-10 mRNA expression but strongly suppressed IL-1beta-induced IL-15 and TNFalpha mRNA expression, indicating that the production of these cytokines by CSA was regulated at the transcriptional level. Results with the calcineurin inhibitor FK-506, but not with the immunosuppressant rapamycin, were similar to those with CSA. Agonists of cAMP displayed an additive effect on the changes produced in the IL-10, IL-15, and TNFalpha levels by CSA, while a cAMP antagonist almost completely abrogated the effect of CSA, suggesting that cAMP is the major intracellular signal that mediates cytokine regulation by CSA.

Conclusion: These results suggest that CSA differentially regulates the production of cytokines by rheumatoid synoviocytes via a cAMP-dependent pathway.