Regulation of interleukin-1β-induced chemokine production and matrix metalloproteinase 2 activation by epigallocatechin-3-gallate in rheumatoid arthritis synovial fibroblasts

Objective. To evaluate the efficacy of epigallocatechin-3-gallate (EGCG), a potent antiinflammatory molecule, in regulating interleukin-1 beta (IL-1 beta)-induced production of the chemokines RANTES (CCL5), monocyte chemoattractant protein 1 (MCP-1/ CCL2), epithelial neutrophil-activating peptide 78 (ENA-78/CXCL5), growth-regulated oncogene alpha (GRO alpha/CXCL1), and matrix metalloproteinase 2 (MMP-2) activity in rheumatoid arthritis (RA) synovial fibroblasts. Methods. Fibroblasts obtained from RA synovium were grown, and conditioned medium was obtained. Cell viability was determined by MTT assay. RANTES, MCP-1, ENA-78, and GRO alpha produced in culture super-natants were measured by enzyme-linked immunosorbent assay. MMP-2 activity was analyzed by gelatin zymography. Western blotting was used to study the phosphorylation of protein kinase C (PKC) isoforms and nuclear translocation of NF-kappa B. Results. EGCG was nontoxic to RA synovial fibroblasts. Treatment with EGCG at 10 mu M or 20 mu M significantly inhibited IL-1 beta-induced ENA-78, RANTES, and GRO alpha, but not MCP-1 production in a concentration-dependent manner. EGCG at 50 mu M caused a complete block of IL-10-induced production of RANTES, ENA-78, and GRO alpha, and reduced production of MCP-1 by 48% (P < 0.05). Zymography showed that EGCG blocked constitutive, IL-1 beta-induced, and chemokine-mediated MMP-2 activity. Evaluation of signaling events revealed that EGCG preferentially blocked the phosphorylation of PKC delta and inhibited the activation and nuclear translocation of NF-kappa B in IL-1 beta-treated RA synovial fibroblasts. Conclusion. These results suggest that EGCG may be of potential therapeutic value in inhibiting joint destruction in RA.