1996 Volume 120 Issue 6 Pages 1203-1208
Tissue-type plasminogen activator (t-PA) and its physiological inhibitor, plasminogen activator inhibitor-1 (PAI-1), are known to be synthesized by vascular endothelial cells and to play important roles in regulating the fibrinolytic activity of plasma. We found that a new butadiene derivative, (3E, 4E)-3-benzylidene-4-(3, 4, 5-trimethoxybenzylidene) pyrrolidine-2, 5-dione (T-686), inhibits PAI-1 production without affecting plasminogen activator (PA) synthesis in cultured bovine endothelial cells. T-686 (1-10 μM) dose-dependently decreased the accumulation of PAI-1 in conditioned medium from the treated cells and elevated PA activity in the conditioned medium. Analysis of the conditioned medium by the zymography technique indicated that T-686 decreased the activities of PAI-1 with an Mr of 55, 000 and t-PA/PAI-1 complex with an Mr of 99, 000. Furthermore, T-686 attenuated the augmentation of PAI-1 antigen induced by lipopolysaccharide in the conditioned medium. The decrease of PAI-1 antigen was in parallel with the reduction of the PAI-1 mRNA level (Northern blots). These results suggest that T-686 can promote net fibrinolytic activity through suppression of PAI-1 production without affecting PA elaboration in endothelial cells.
