The expression of the receptor for advanced glycation end-products (RAGE) in RA-FLS is induced by IL-17 via Act-1

INTRODUCTION The receptor for advanced glycation end-products (RAGE) has been implicated in the pathogenesis of arthritis. We conducted this study to determine the effect of interleukin (IL)-17 on the expression and production of RAGE in fibroblast-like synoviocytes (FLS) from patients with rheumatoid arthritis (RA). The role of nuclear factor-κB (NF-κB) activator 1 (Act1) in IL-17-induced RAGE expression in RA-FLS was also evaluated. METHODS RAGE expression in synovial tissues was assessed by immunohistochemical staining. RAGE mRNA production was determined by real-time polymerase chain reaction. Act-1 short hairpin RNA (shRNA) was produced and treated to evaluate the role of Act-1 on RAGE production. RESULTS RAGE, IL-17, and Act-1 expression increased in RA synovium compared to osteoarthritis synovium. RAGE expression and production increased by IL-17 and IL-1β (*P <0.05 vs. untreated cells) treatment but not by tumor necrosis factor (TNF)-α in RA-FLS. The combined stimuli of both IL-17 and IL-1β significantly increased RAGE production compared to a single stimulus with IL-17 or IL-1β alone (P <0.05 vs. 10 ng/ml IL-17). Act-1 shRNA added to the RA-FLS culture supernatant completely suppressed the enhanced production of RAGE induced by IL-17. CONCLUSIONS RAGE was overexpressed in RA synovial tissues, and RAGE production was stimulated by IL-17 and IL-1β. Act-1 contributed to the stimulatory effect of IL-17 on RAGE production, suggesting a possible inhibitory target for RA treatment.