A comparative proteomics study of a synovial cell line stimulated with TNF-α.

To elucidate the pathogenesis of rheumatoid arthritis (RA), we used proteomic analysis to determine the protein profile in a synovial cell line, MH7A, established from patients with RA. Proteins were extracted from MH7A cells that were or were not stimulated with tumor necrosis factor-α (TNF-α), and then analyzed on a liquid chromatography/mass spectrometry system equipped with a unique long monolithic silica capillary. On the basis of the results of this proteomic analysis, we identified 2650 proteins from untreated MH7A cells and 2688 proteins from MH7A cells stimulated with TNF-α. Next, we selected 269 differentially produced proteins that were detected only under TNF-α stimulation, and classified these proteins by performing gene ontology analysis by using DAVID as a functional annotation tool. In TNF-α-stimulated MH7A cells, we observed substantial production of plasminogen-activator inhibitor 2 and apoptosis-regulating proteins such as BH3-interacting domain death agonist, autophagy protein 5, apolipoprotein E, and caspase-3. These results indicate that the upregulation of plasminogen-activator inhibitor 2 and apoptosis-regulating proteins in synovial cells in response to TNF-α stimulation might represent a predominant factor that contributes to the pathogenesis of RA.