Disease-modifying antirheumatic drug (DMARD) response signatures in human chondrocytes. Centroid view (fold change) of rheumatoid arthritis (RA)-related chondrocyte gene expression following treatment of rheumatoid arthritis synovial fibroblasts (RASFs) with DMARDs azathioprine, gold sodium thiomalate, chloroquine phosphate, and methotrexate. Black bars represent the RA-related gene expression in human chondrocytes (differential gene expression of RASFsn-stimulated chondrocytes versus NDSFsn stimulation). Grey bars represent the DMARD response signatures in human chondrocytes (differential gene expression of human chondrocytes stimulated with drug-treated RASFs compared with stimulation with untreated RASFs). Azathioprine, gold sodium thiomalate, and methotrexate treatment of RASFs resulted in a reverted gene expression of the majority of RA-related genes in human chondrocytes. In contrast, RASF treatment with chloroquine phosphate had only minor effects. NDSFsn, supernatant of untreated normal (healthy) donor synovial fibroblast; NF-κB, nuclear factor-kappa-B; RASFsn, supernatant of untreated rheumatoid arthritis synovial fibroblast.