Serotonin induces the expression of tissue factor and plasminogen activator inhibitor-1 in cultured rat aortic endothelial cells

Blood ◽  
2001 ◽  
Vol 97 (6) ◽  
pp. 1697-1702 ◽  
Author(s):  
Hidehiko Kawano ◽  
Hajime Tsuji ◽  
Hiromi Nishimura ◽  
Shinzo Kimura ◽  
Shingo Yano ◽  
...  

Serotonin (5-hydroxytryptamine, or 5-HT), released from activated platelets, not only accelerates aggregation of platelets but also is known to promote mitosis, migration, and contraction of vascular smooth muscle cells (VSMCs). These effects are considered to contribute to thrombus formation and atherosclerosis. The aim of this study was to investigate the effects of 5-HT on the expressions of coagulative and fibrinolytic factors in rat aortic endothelial cells. Endothelial cells were stimulated with various concentrations of 5-HT (0.1∼10 μM), and the expressions of tissue factor (TF), tissue factor pathway inhibitor (TFPI), plasminogen activator inhibitor-1 (PAI-1), and tissue-type plasminogen activator (TPA) messenger RNAs (mRNAs) were evaluated by Northern blot analysis. The activities of TF and PAI-1 were also measured. TF and PAI-1 mRNA were increased significantly in a concentration- and time-dependent manner. However, TFPI and TPA mRNA expression did not change. The inductions of TF and PAI-1 mRNAs were inhibited by a 5-HT1/5-HT2 receptor antagonist (methiothepin) and a selective 5-HT2A receptor antagonist (MCI-9042). These results indicate that 5-HT increases procoagulant activity and reduces fibrinolytic activities of endothelial cells through the 5-HT2A receptor. It was concluded that the modulation of procoagulant and hypofibrinolytic activities of endothelial cells by 5-HT synergistically promotes thrombus formation at the site of vessel injury with the platelet aggregation, VSMC contraction, and VSMC proliferation.

1997 ◽  
Vol 77 (06) ◽  
pp. 1189-1195 ◽  
Author(s):  
Hiromi Nishimura ◽  
Hajime Tsuji ◽  
Haruchika Masuda ◽  
Katsumi Nakagawa ◽  
Yoshihumi Nakahara ◽  
...  

SummaryAngiotensin converting enzyme inhibitors (ACE-I) have been reported to prevent the recurrence of cardiovascular events. The mechanism of this decrease, however, can not be completely explained by anti-hypertensive and anti-hypertrophic effects of ACE-I. To investigate the mechanism of this decrease, we studied the regulation of plasminogen activator inhibitor-1 (PAI-1), tissue type plasminogen activator (TPA), tissue factor (TF), and tissue factor pathway inhibitor (TFPI) by angiotensin II (Ang II) in cultured rat aortic endothelial cells. Ang II increased PAI-1 and TF mRNA expression without affecting that of TPA or TFPI. These inductions were accompanied by increases in PAI-1 and TF activities and were inhibited by a type 1 Ang II receptor antagonist. The results suggest that Ang II decreases the antithrombotic properties of endothelial cells which increases the chance of thrombosis. Thus, inhibition of the renin-angiotensin system may be beneficial to prevent thrombus formation in treatment of ischemic heart disease.


2002 ◽  
Vol 88 (12) ◽  
pp. 1060-1065 ◽  
Author(s):  
Ana Pérez-Ruiz ◽  
Ramón Montes ◽  
Francisco Velasco ◽  
Chary López-Pedrera ◽  
José Páramo ◽  
...  

SummaryThe increase in nitric oxide (NO) production in lipopolysaccharide (LPS)-induced sepsis is thought to contribute to the development of shock. However, NO could also play an antithrombotic role. Little is known about the modulating effect of NO on the endothelial overexpression and production of tissue factor (TF) and plasminogen activator inhibitor-1 (PAI-1) occurring in endotoxemia. We analyzed the effect of N(G)-nitro-L-arginine-methyl-ester (L-NAME), an inhibitor of NO synthases, and S-nitroso-N-acetyl-D,L-penicillamine (SNAP), a NO donor, on the expression and synthesis of TF and PAI-1 by LPS-challenged human umbilical vein endothelial cells (HUVEC): L-NAME enhanced the increase in TF mRNA and antigen levels (P <0.05) observed in LPS-treated HUVEC; SNAP down-regulated the LPSinduced TF increment (p <0.05). However, no effects of NO on regulation of the LPS-dependent increase in PAI-1 could be seen. Thus, NO could play an antithrombotic role in sepsis by down-regulating the endothelial overexpression and production of TF.


1998 ◽  
Vol 79 (03) ◽  
pp. 631-634 ◽  
Author(s):  
Hajime Tsuji ◽  
Hiromi Nishimura ◽  
Teruhisa Kasahara ◽  
Tatsuya Sugano ◽  
Haruchika Masuda ◽  
...  

SummaryThe pharmacological characteristics of atrial natriuretic peptide (ANP), such as natriuresis, vasodilation, or suppression of smooth muscle cell proliferation, are well investigated. However, this is the first study to report its role on blood coagulation and fibrinolysis mediated by vascular endothelial cells. In this study, the effects of ANP on the enhanced expression of tissue factor (TF) and plasminogen activator inhibitor 1 (PAI-1) by angiotensin II (Ang II) in cultured rat aortic endothelial cells (RAECs) were examined. The expressions of TF and PAI-1 mRNA were detected by northern blotting methods. The activities of TF on the surface of RAECs and PAI-1 in the culture media were measured by chromogenic assay. ANP suppressed mRNA expressions of TF and PAI-1 induced by Ang II in a concentration-dependent manner. This suppression was accompanied by the decreased activities of TF and PAI-1.


Stroke ◽  
2014 ◽  
Vol 45 (suppl_1) ◽  
Author(s):  
Qi Liu ◽  
Xiang Fan ◽  
Helen Brogren ◽  
Ming-Ming Ning ◽  
Eng H Lo ◽  
...  

Aims: Plasminogen activator inhibitor-1 (PAI-1) is the main and potent endogenous tissue-type plasminogen activator (tPA) inhibitor, but an important question on whether PAI-1 in blood stream responds and interferes with the exogenously administered tPA remains unexplored. We for the first time investigated temporal profiles of PAI-1 concentration and activity in circulation after stroke and tPA administration in rats. Methods: Permanent MCAO focal stroke of rats were treated with saline or 10mg/kg tPA at 3 hours after stroke (n=10 per group). Plasma (platelet free) PAI-1 antigen and activity levels were measured by ELISA at before stroke, 3, 4.5 (1.5 hours after saline or tPA treatments) and 24 hours after stroke. Since vascular endothelial cells and platelets are two major cellular sources for PAI-1 in circulation, we measured releases of PAI-1 from cultured endothelial cells and isolated platelets after direct tPA (4 μg/ml) exposures for 60 min in vitro by ELISA (n=4 per group). Results: At 3 hours after stroke, both plasma PAI-1 antigen and activity were significantly increased (3.09±0.67, and 3.42±0.57 fold of before stroke baseline, respectively, all data are expressed as mean±SE). At 4.5 hours after stroke, intravenous tPA administration significantly further elevated PAI-1 antigen levels (5.26±1.24), while as expected that tPA neutralized most elevated PAI-1 activity (0.33±0.05). At 24 hours after stroke, PAI-1 antigen levels returned to the before baseline level, however, there was a significantly higher PAI-1 activity (2.51±0.53) in tPA treated rats. In vitro tPA exposures significantly increased PAI-1 releases into culture medium in cultured endothelial cells (1.65±0.08) and platelets (2.02±0.17). Conclution: Our experimental results suggest that tPA administration may further elevate stroke-increased blood PAI-1 concentration, but also increase PAI-1 activity at late 24 hours after stroke. The increased PAI-1 releases after tPA exposures in vitro suggest tPA may directly stimulate PAI-1 secretions from vascular walls and circulation platelets, which partially contributes to the PAI-1 elevation observed in focal stroke rats. The underlying regulation mechanisms and pathological consequence need further investigation.


Blood ◽  
1996 ◽  
Vol 87 (10) ◽  
pp. 4204-4213 ◽  
Author(s):  
S Handt ◽  
WG Jerome ◽  
L Tietze ◽  
RR Hantgan

Time-dependent thrombolytic resistance is a critical problem in thrombolytic therapy for acute myocardial infarction. Platelets have been regarded as the main source of plasminogen activator inhibitor-1 (PAI-1) found in occlusive platelet-rich clots. However, endothelial cells are also known to influence the fibrinolytic capacity of blood vessels, but their ability to actively mediate time-dependent thrombolytic resistance has not been fully established. We will show that, in vitro, tumor necrosis factor-alpha-stimulated endothelial cells secrete large amounts of PAI-1 over a period of hours, which then binds to fibrin and protects the clot from tissue plasminogen activator- induced fibrinolysis. In vivo, endothelial cells covering atherosclerotic plaques are influenced by cytokines synthesized by plaque cells. Therefore, we propose that continuous activation of endothelial cells in atherosclerotic blood vessels, followed by elevated PAI-1 secretion and storage of active PAI-1 in the fibrin matrix, leads to clot stabilization. This scenario makes endothelial cells a major factor in time-dependent thrombolytic resistance.


Blood ◽  
2000 ◽  
Vol 96 (1) ◽  
pp. 153-160
Author(s):  
Tomihisa Kawasaki ◽  
Mieke Dewerchin ◽  
Henri R. Lijnen ◽  
Jos Vermylen ◽  
Marc F. Hoylaerts

The role of plasminogen activator inhibitor-1 (PAI-1) in the plasma, blood platelets, and vessel wall during acute arterial thrombus formation was investigated in gene-deficient mice. Photochemically induced thrombosis in the carotid artery was analyzed via transillumination. In comparison to thrombosis in C57BL/6J wild-type (wt) mice (113 ± 19 × 106 arbitrary light units [AU] n = 15, mean ± SEM), thrombosis in PAI-1−/− mice (40 ± 10 × 106 AU, n = 13) was inhibited (P < .01), indicating that PAI-1 controls fibrinolysis during thrombus formation. Systemic administration of murine PAI-1 into PAI-1−/− mice led to a full recovery of thrombotic response. Occurrence of fibrinolytic activity was confirmed in 2-antiplasmin (2-AP)–deficient mice. The sizes of thrombi developing in wt mice, in 2-AP+/− and 2-AP−/− mice were 102 ± 35, 65 ± 8.1, and 13 ± 6.1 × 106 AU, respectively (n = 6 each) (P < .05), compatible with functional plasmin inhibition by 2-AP. In contrast, thrombi in wt mice, t-PA−/− and u-PA−/−mice were comparable, substantiating efficient inhibition of fibrinolysis by the combined PAI-1/2-AP action. Platelet depletion and reconstitution confirmed a normal thrombotic response in wt mice, reconstituted with PAI-1−/− platelets, but weak thrombosis in PAI-1−/− mice reconstituted with wt platelets. Accordingly, murine (wt) PAI-1 levels in platelet lysates and releasates were 0.43 ± 0.09 ng/109 platelets and plasma concentrations equaled 0.73 ± 0.13 ng/mL. After photochemical injury, plasma PAI-1 rose to 2.9 ± 0.7 ng/mL (n = 9, P < .01). The plasma rise was prevented by ligating the carotid artery. Hence, during acute thrombosis, fibrinolysis is efficiently prevented by plasma 2-AP, but also by vascular PAI-1, locally released into the circulation after endothelial injury.


2002 ◽  
Vol 87 (3) ◽  
pp. 1419-1422 ◽  
Author(s):  
Ahmad Aljada ◽  
Husam Ghanim ◽  
Priya Mohanty ◽  
Neeti Kapur ◽  
Paresh Dandona

We have recently demonstrated that an infusion of a low dose of insulin reduces the intranuclear NF-κB (a pro-inflammatory transcription factor) content in MNC while also reducing the p;asma concentration of NF-κB dependent pro-inflammatory cytokines and adhesion molecules. We have now tested the effect of insulin on the pro-inflammatory transcription factor, early growth response-1 (Egr-1) and plasma concentration of tissue factor (TF) and plasminogen activator inhibitor-1 (PAI-1), two major proteins whose expression is modulated by Egr-1. Insulin was infused at the rate of 2 IU/h in 5% dextrose (100 mL/h) and KCI (8 mmol/h) for 4 h in the fasting state in ten obese subjects. Blood samples were obtained at 0, 2, 4 and 6 h. MNC were isolated and their total homogenates and nuclear fractions were prepared and Egr-1 was measured by electrophoretic mobility shift assay (EMSA). Plasma TF and PAI-1 were assayed by ELISA. There was a significant fall in Egr-1 at 2 (66 ± 14% of basal level) and 4 h (47± 17% of the basal level; P&lt;0.01). PAI-1 levels (basal = 100%) decreased significantly after insulin infusion at 2 h (57 ± 6.7% of the basal level) and at 4 h (58 ± 8.3% of the basal level; P&lt;0.001). Plasma TF levels (basal = 100%) decreased to 76 ± 7.7% of the basal level at 2 h and to 85 ± 10.4% of the basal level at 4 h (P&lt;0.05). Thus, insulin reduces intranuclear Egr-1 and the expression of TF and PAI-1. These data provide further evidence that insulin has an anti-inflammatory effect including the inhibition of TF and PAI-1 expression. These effects suggest a potential beneficial effect of insulin in thrombin formation and fibrinolysis in atherothrombosis.


Blood ◽  
2004 ◽  
Vol 103 (4) ◽  
pp. 1319-1324 ◽  
Author(s):  
Khalid N. I. Al-Nedawi ◽  
Malgorzata Czyz ◽  
Radoslaw Bednarek ◽  
Janusz Szemraj ◽  
Maria Swiatkowska ◽  
...  

Abstract Thymosin β4(Tβ4), a 4.9-kDa polypeptide primarily known as a main G-actin–sequestering peptide, is present in high concentrations in various cells and in the circulation. We have found that Tβ4 upregulates the expression of plasminogen activator inhibitor 1 (PAI-1) in endothelial cells measured both at the level of mRNA and protein synthesis. This effect seems to be cell specific and was not observed when other cells such as human fibroblasts, PC3, and U937 were tested. Tβ4 significantly activated the PAI-1 promoter in EA.hy 926 cells transiently transfected either with plasmid p800LUC containing PAI-1 promoter fragment (–800 to +71) or the PAI-1 promoter linked with green fluorescent protein. Tβ4 mediated up-regulation of PAI-1 involved activation of the mitogen-activated protein kinase cascade. Furthermore, Tβ4 enhanced c-Fos/c-Jun DNA-binding activity to the activator protein 1 (AP-1)–like element (–59 to –52). The specificity of this binding activity was demonstrated by competition electrophoretic mobility shift assay and after transfection of EA.hy 926 cells with the mutated PAI-1 promoter. Taken together, these data indicate that, in response to Tβ4 stimulation, AP-1 activity increases to enhance PAI-1 transcription through its unique AP-1–like element at –59 to –52 in the PAI-1 promoter.


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