Figure 2

Matrix metalloproteinase (MMP)-2 upregulation by macrophage migration inhibitory factor (MIF) is time-dependent. (a) Using gelatin zymography of rheumatoid arthritis (RA) synovial fibroblast culture supernatants, we found MMP-2 upregulation, beginning after 1 hour and increasing continuously over a period of 24 hours. The results represent one of four individual experiments using cells from four donors. (b) Immunofluorescence staining of RA synovial fibroblasts for MMP-2 showed a strong perinuclear and discrete diffuse cytoplasmic expression after 1 hour of stimulation by MIF (50 nM; 400×). Results represent one of four individual experiments using cells from four donors. NS, nonstimulated; pro-MMP, pro-matrix metalloproteinase-2; rhMIF, recombinant human macrophage migration inhibitory factor.