Human synovial fibroblast plasminogen activator. modulation of enzyme activity by antiinflammatory steroids

Abstract

Human synovial fibroblasts in culture have been shown to have low plasminogen activator (PA) activity; however, conditioned medium from concanavalin A‐stimulated peripheral blood mononuclear cells (c‐MCCM) stimulates the cellular levels of this protease. The present study shows that low concentrations of a series of antiinflammatory steroids inhibit the PA activities of both unstimulated and c‐MCCM‐stimulated fibroblasts. Dexamethasone, the corticosteroid studied in greatest detail, suppresses both the extracellular and cell‐associated enzyme activities; this inhibition is rapid, reversible, and is not due to the inhibition of cellular RNA, protein, or DNA synthesis. PA has been invoked as p..