Abstract
Umbelliferone (UMB), a natural coumarin compound, has been reported to possess anti-rheumatic effects on rheumatoid arthritis (RA) experimental models, but its potential role of UMB in regulating migration, invasion and inflammation of RA fibroblast-like synoviocytes (FLS) remain unclear. Herein, MTT assay was performed to confirm the non-cytotoxic concentrations (10, 20, and 40M) and the treatment time (24h) of UMB on TNF--stimulated RA FLS (MH7A cells) in vitro. Results of wound-healing, transwell and phalloidin staining assays revealed that UMB inhibited TNF--induced migration, invasion and F-actin cytoskeletal reorganization in MH7A. Results of ELISA, western blot and gelatin zymography indicated that UMB decreased the productions of pro-inflammatory factors, including IL-1, IL-6, IL-8, MMP-2 and MMP-9, and inhibited MMP-2 activity in TNF--stimulated MH7A cells. In vivo, UMB (25mg/kg and 50mg/kg) relieved the joint damage and synovial inflammation in rats with adjuvant-induced arthritis (AIA). Mechanistically, UMB could suppress Wnt/-catenin signaling both in TNF--induced MH7A cells and in AIA rat synovium, evidenced by decreasing Wnt1 protein level, activating GSK-3 kinase by blocking GSK-3 (Ser9) phosphorylation, and reducing the protein level and nuclear translocation of -catenin. Importantly, combined use of lithium chloride (a Wnt/-catenin signaling agonist) eliminated the inhibitory effects of UMB on migration, invasion and inflammation in vitro and the anti-arthritic effects of UMB in vivo. We concluded that UMB inhibited TNF--induced migration, invasion and inflammation of RA FLS and attenuated the severity of rat AIA through its ability to block Wnt/-catenin signaling pathway.
