SYNOVIAL CELL ACTIVATION - STUDIES ON THE MECHANISM OF ACTION OF SYNOVIAL ACTIVATOR ACTIVITY

  • 1 January 1983
    • journal article
    • research article
    • Vol. 10  (6) , 872-880
Abstract
Synovial activator (SA) from peripheral blood mononuclear cells stimulates the plasminogen activator (PA) levels of human synovial fibroblasts. Using the sensitive technique of transcriptional inhibition followed by a prolonged translation period, data suggested that the 1st synthesis of mRNA needed for the increase in PA activity began within 40-60 min; this increase in protease activity was reversible on removal of SA from the cultures and also declined after about 3 days even in SA was not withdrawn. The RNA dependent events necessary for the synovial cell activation were to a large extent completed by about 4-8 h while those dependent on protein synthesis lasted for about 12 h. The effectiveness of suboptimal concentrations of SA could be potentiated by all-trans retinoic acid. A similar potentiation was effected by phosphodiesterase inhibitors, 3-isobutyl-1-methylxanthine adn theophylline, by 8-bromo-cAMP and by prostaglandins of the E and F series; cyclic nucleotide involvement in the SA-mediated elevation of synovial fibroblast PA activity is suggested.