Anti-inflammatory and anti-osteoarthritis effects of Cm-02 and Ck-02.

ABSTRACT

Osteoarthritis (OA) is a common degenerative joint disease characterized by progressive deterioration of articular cartilage. There have been reports that small molecule inhibitors have anti-osteoarthritis effects; however, the effects of 3-(4-chloro-2-fluorophenyl)-6-(2,4-difluorophenyl)-2H-benzo[e] [1,3]oxazine-2,4(3H)-dione (Cm-02) and 6-(2,4-difluorophenyl)-3-(3,4-difluorophenyl)-2H-benzo[e] [1,3]oxazine-2,4(3H)-dione (Ck-02), small molecule inhibitors which share many structural similarities with quercetin (a potent anti-inflammatory flavonoid), remain unclear. In this study, TNF-α-stimulated porcine and human chondrocyte models were used to investigate the inhibitory effects of Cm-02 and Ck-02 on the molecular mechanisms underlying the anti-OA effects. TNF-α was used to stimulate porcine and human chondrocytes to mimic immunomodulatory potency in-vitro. Anti-osteoarthritic effects were characterized in terms of protein and mRNA levels associated with the pathogenesis of OA. We also examined (1) the inducible nitric oxide synthase (iNOS)-nitric oxide (NO) system in cultured chondrocytes, (2) matrix metalloproteinases (MMPs) in cultured chondrocytes, and (3) aggrecan degradation in cartilage explants. Finally, we tested the activation of nuclear factor-kappaB (NF-κB), interferon regulatory factor-1 (IRF-1), and activate the protein-1 (AP-1), and we tested the signal transduction and activation of transcription-3 (STAT-3). Our results indicate that, in chondrocytes, Cm-02 and Ck-02 inhibit TNF-α induced NO production, iNOS, MMP, the expression of disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS), and the enzyme activity of MMP-13. Furthermore, both Cm-02 and Ck-02 were found to stimulate TNF-α, which has been shown to suppress the activation of several transcription factors, including NF-κB, STAT-3, and IRF-1 in porcine and human chondrocytes. Cm-02 and Ck-02 were also found to help prevent the release of proteoglycans from cartilage explants. Our findings demonstrate that both Cm-02 and Ck-02 have potent anti-inflammatory activities and the ability to protect cartilage in an OA cell model. These findings indicate that Cm-02 and Ck-02 have the potential to be further developed for the therapeutic treatment of OA.