Heterogeneous regulation of constitutive thrombomodulin or inducible tissue-factor activities on the surface of human saphenous-vein endothelial cells in culture following stimulation by interleukin-1, tumour necrosis factor, thrombin or phorbol ester

Abstract

Thrombomodulin and tissue-factor activities were measured on the surface of confluent human saphenous-vein endothelial cells (HSVEC) cultivated in 96-multiwell plates. Thrombomodulin activity was measured in the presence of purified human thrombin (2.2 nM) and protein C (65 nM). Tissue-factor activity was measured with purified human Factor VII (5 nM) and Factor X (400 nM). Generated activated protein C and Factor Xa released in the supernatant were assayed with chromogenic substrates. Resting cells exhibited significant thrombomodulin activity, but no detectable tissue-factor activity. After 4 h of preincubation with tumour necrosis factor (TNF, 22-2200 pM), interleukin-1 (IL-1, 5.7-570 nM) or phorbol myristate acetate (PMA, 1.61-161 nM) there was an increase in tissue-factor activity and a concomitant decrease in thrombomodulin activity. However, the extent of both responses varied according to the nature of the stimulus. Thrombin (0.44-44 nM) also induced an increase in tissue-factor activity, but had no effect on thrombomodulin activity. Kinetic studies showed that for all stimuli the increase in tissue factor was transient, reaching a maximum after 4-8 h of preincubation with the stimulating agent and returning to normal values after 24 h. IL-1 and TNF induced a time-dependent decrease in thrombomodulin, by respectively 47% and 67% of control values after 24 h. However, PMA induced only a transient down-regulation of thrombomodulin, full activity being recovered after 18 h. Hence this simultaneous assay system, using intact HSVEC and purified human coagulation factors, enabled us to observe that the regulation of thrombin generation could be diversely affected by various substances known to stimulate the endothelium. This suggests that the simultaneous and opposite modulation of these proteins does not represent an unified response of the endothelial cells to procoagulant stimuli. These results also confirm the absence of effect of thrombin on the expression of thrombomodulin on the cell surface.

IL‐4 inhibits LPS‐, IL‐1β‐ and TNFα‐induced expression of tissue factor in endothelial cells and monocytes

“…The TF activity was normalized to the cell counts from the same well and expressed as,aU of TF/10 s ¢¢11s. expression of TF which reached a maximum around 6 h. These results confirm previous observations showing that these compounds induce endothelial cell procoagulant activity while suppressing cell-surface anticoagulant activity [11,12]. For both ABAE and monocytes, TF expression in control wells did not vary significantly over the 24-h incubation period and the passage number had no effect on the procoagulant activity of the various inflammatory mediators (not shown).…”

Statin Prevents Tissue Factor Expression in Human Endothelial Cells

“…7 However, the signaling mechanisms underlying tissue factor expression are not fully understood. Here, we showed that thrombin-induced tissue factor expression is regulated positively by Rho/Rho-kinase and p38 MAP kinase.…”

“…5 Indeed, thrombin induces platelet aggregation 6 and tissue factor expression. 7 Thus, thrombin is a key modulator of this positive feedback mechanism of thrombus formation. However, the signaling pathways responsible for thrombin-induced tissue factor expression remain unclear.…”

Venous thromboembolism in systemic autoimmune diseases: A narrative review with emphasis on primary systemic vasculitides

“…[16][17][18] Another inflammatory cytokine, interleukin 1 has also been shown to reduce thrombomodulin activity on endothelial cells. 19,20 Another important pathway linking inflammation and coagulation is the fibrinolytic system. Plasminogen is converted to plasmin by tissue-type plasminogen activator (t-PA) or urokinase-type plasminogen activator (u-PA), both of which are regulated by plasminogen activator inhibitor-1 (PAI-1).…”