Inhibition of Plasminogen Activator Inhibitor-1 by 11-Keto-9(E), 12(E)-octadecadienoic Acid, a Novel Fatty Acid Produced by Trichoderma sp

We have recently found a novel fatty acid, 11-keto-9(E), 12(E)-octadecadienoic acid (KOD), that enhances fibrinolytic activity of endothelial cells. The mechanism of action of KOD has been investigated. KOD increased 2-fold the plasmin activity of bovine aortic endothelial cells at 250 μM. The stimulation was dependent on plasminogen and was inhibited by anti-urokinase, whereas KOD did not enhance the urokinase-catalyzed plasminogen activation and the resulting plasmin activity in a cell-free system. Neither the production of urokinase nor the conversion of pro-urokinase to the active, two-chain form was elevated by KOD, but it decreased plasminogen activator inhibitor-1 (PAI-1) activity of cells and inactivated PAI-1 irreversibly in a purified system. These results demonstrated that the KOD enhancement of endothelial fibrinolytic activity was mediated, at least in part, by inactivation of PAI-1.