Role of LIGHT in the pathogenesis of joint destruction in rheumatoid arthritis

Figure 1 LIGHT induces receptor-activator nuclear factor kappa-B ligand-independent osteoclastogenesis from rheumatoid arthritis synovial fluid macrophages. A: Osteoclast differentiation in 14-d cultures of RA SF macrophages incubated with M-CSF and LIGHT showing (left) TRAP+ multinucleated osteoclasts and (right) F actin-ring formation; B: Dentine slices stained with Toluidine blue showing lacunar resorption in 14-d RA SF macrophage cultures treated with M-CSF and sRANKL, LIGHT or LIGHT ± OPG; C: Percentage surface area lacunar resorption on dentine slices in LIGHT- (± OPG) treated SF macrophage cultures relative to sRANKL - treated controls; data is expressed as mean ± SEM of three independent experiments where each condition was carried out in triplicate. RANKL: Receptor-activator nuclear factor kappa-B ligand; RA: Rheumatoid arthritis; SF: Synovial fluid; M-CSF: Macrophage-colony stimulating factor; OPG: Osteoprotegerin.