Effect of fibronectin fragment on monocyte chemotactic protein expression in synovial fibroblasts from human temporomandibular joints

Abstract

Metabolites of extracellular matrix have been shown to be one of the pathogens for chronic inflammation. Fibronectin, an extracellular matrix component, is degraded by enzymes such as matrix metalloproteinase. Fibronectin fragments (FN-Fs; 30-200 kDa molecular weight) are present at high levels in synovial fluid from osteoarthritis patients, and are associated with inflammatory conditions. In this study, we investigated the role of FN-Fs in inflammation pathogens of temporomandibular joint disorders (TMDs). Synovial fibroblasts were prepared from synovium of the temporomandibular joint (TMJ) with internal derangement using the outgrowth method. Synovial fibroblasts were treated with 30 kDa FN-F. Gene expression was examined using a real-time PCR method. The FN-F induced the gene expression of monocyte chemotactic protein (MCP) -1, -2, and -3 in synovial fibroblasts from human TMJ synovium. The protein level of MCP-1, one of the best-known MCP members, was measured using ELISA. The protein concentration of MCP-1 was increased in the conditioned medium from synovial fibroblasts treated with 30 kDa FN-F. Furthermore, signal inhibitor experiments indicated that 30 kDa FN-F mediated induction of MCP-1 was inhibited via activation of NF-κB. MCP production mainly modulates monocyte/macrophage recruitment in multiple inflammatory diseases. These results suggest that 30 kDa FN-F is associated with the progression of inflammation of TMDs.