Nuclear factor-κB regulates RANTES chemokine expression in response to tumor necrosis factor-α in fibroblast-like synoviocytes

Abstract

We investigated the role of nuclear factor (NF)-κB on tumor necrosis factor (TNF)-α-induced regulated upon activation, normal T-cell expressed and secreted (RANTES) expression in fibroblast-like synoviocytes from patients with rheumatoid arthritis (RA). Using cultured human fibroblast-like synoviocytes from patients with RA, semiquantitative reverse transcriptase-polymerase chain reaction, electrophoretic mobility shift assay, and Western blot were performed for RANTES expression, NF-κB activation, and degradation of IκB, respectively. In addition, the transcriptional effect of TNF-α on RANTES gene expression was analyzed by reporter gene assay. We found that TNF-α clearly induced RANTES protein production and expression of RANTES mRNA in a time-dependent manner. Furthermore, TNF-α persistently induced NF-κB activation caused by IκBα and IκBβ1 degradation. Supershift analysis revealed that TNF-α-induced DNA-binding complexes were composed principally of the p65 and p50 Rel family members. Moreover, transcriptional activation of the RANTES promoter by TNF-α was dependent on specific NF-κB response elements that were regulated by NF-κB. Results herein indicate that NF-κB activation caused by degradation of IκBα and IκBβ1 by TNF-α increased RANTES gene expression in fibroblast-like synoviocytes, suggesting that NF-κB plays an important role in the migration of inflammatory cells by RANTES to the synovium in patients with rheumatoid arthritis.

Key words::

• Nuclear factor (NF)-κB
• Regulated upon activation, normal T-cell expressed and secreted (RANTES)
• Rheumatoid arthritis (RA)
• Synoviocyte
• Tumor necrosis factor (TNF)-α