CM1 Enhances Proinflammatory cytokine Production in Peripheral Blood Mononuclear Cells and Synovial Fluid Mononuclear Cells from Rheumatoid Arthritis Patients (99.53)

Abstract

Abstract CM1 (centrocyte/-blast marker 1) is expressed on the surface of activated peripheral blood mononuclear cells (PBMCs). Recently, we found that the production of prostaglandin E2 (PGE2) from activated PBMCs was increased by CM1 stimulation via the activation of nuclear factor kappa B (NF-kB). Therefore, this study was attempted to investigate the roles of CM1 in the regulation of rheumatoid arthritis (RA). PBMCs were purified from healthy donors, RA patients and degenerative osteoarthritis (OA) patients, and knee joint synovial fluid mononuclear cells (SFMCs) were purified from RA patients. The expression of CM1 on PBMCs and SFMCs were analyzed by flowcytometry. The production of inflammatory cytokines and PGE2 by CM1 stimulation was measured by ELISA and chromatin immunoprecipitation (ChIP) assay and immunoblotting were performed to examine signaling mediators for inflammatory cytokines by CM1 stimulation. CM1 is highly expressed on PBMCs and SFMCs from RA patients, but not from OA patients. TNF-alpha, IL-1 alpha/beta, IFN-gamma and PGE2 production were markedly increased in PBMCs and SFMCs of RA patients upon CM1 stimulation. The phosphorylation of p38 MAPK was increased in PBMCs and SFMCs from RA patients in a time dependent manner after CM1 stimulation. In addition, the binding of NF-kB to the promoters of TNF-alpha and IL-1 beta after CM1 stimulation was also confirmed by the ChIP assay. Our results strongly suggest that CM1 may play a critical role in the disease progression of RA via the induction of disease-related proinflammatory cytokines and PGE2 production.