Figure 5

Macrophage migration inhibitory factor (MIF)-induced matrix metalloproteinase (MMP)-2 production is PKCδ, JNK, and Src pathway-dependent. Rheumatoid arthritis (RA) synovial fibroblasts were incubated for 6 hours, with or without MIF (50 nM), in the presence or absence of signaling pathway inhibitors: PKC (pan) inhibitor Ro-31-8425 (1 μM), PKCδ isoform-specific inhibitor rottlerin (1 μM), JNK inhibitor JNK II, and Src inhibitor PP2 (10 μM). (a) MMP-2 concentrations in cell culture supernatants were measured by ELISA. Inhibitors to PKCδ, JNK, and Src signaling intermediates inhibited MIF-induced MMP-2 upregulation. (b) Gelatin zymography showed the same effect of these inhibitors on MMP-2 upregulation. Results represent three experiments using RA synovial fibroblasts from six donors. DMSO, dimethyl sulfoxide; JNK, c-jun N-terminal kinase; NS, non-stimulated; pro-MMP, pro-matrix metalloproteinase-2; PKC, protein kinase C; rhMIF, recombinant human macrophage migration inhibitory factor.