Effects of prostaglandin E2, indomethacin, trifluoperazine and drugs affecting the cytoskeleton on collagenase production by cultured adherent rheumatoid synovial cells.

Cultured adherent rheumatoid synovial cells with fibroblast properties release large amounts of collagenase and prostaglandin E2 (PGE2) into the medium. With age in culture and passage of the cells, the levels of collagenase and PGE2 decrease, but can be increased by a factor (MCF; mononuclear cell factor) released by cultured human blood monocyte-macrophages. The magnitude of the stimulation varies with different synovial cell strains. To determine some of the mechanisms which regulate the collagenase response, synovial cells were exposed to a cyclooxygenase inhibitor (indomethacin) and substances which alter the cytoskeleton (cytochalasin B or colchicine) or interact with Ca2+ X calmodulin (trifluoperazine). The collagenase response was retained even when PGE2 synthesis was totally blocked with indomethacin. The collagenase response, however, was blunted at high indomethacin concentrations (greater than 10 microM) and paradoxically augmented at lower indomethacin concentrations (0.001 microM). In some synovial cell strains, the blunting effect of 10 microM indomethacin was reversed by the addition of low concentrations of exogenous PGE2 (10 ng/ml). Preincubation of synovial cells for 1 or 24 hr with colchicine or cytochalasin B (1-10 microM) resulted in an augmented collagenase and PGE2 response to MCF. Cells preincubated or incubated with 1-50 microM trifluoperazine, a phenothiazine, also augmented collagenase stimulation by MCF, but, in contrast to colchicine or cytochalasin B, trifluoperazine suppressed the PGE2 response. Thus, although PGE2 and collagenase production by synovial cells may be dissociated, altering ambient PGE2 levels affected basal collagenase production and modulated the collagenase response to MCF.