scholarly journals Coordinated induction of plasminogen activator inhibitor-1 (PAI-1) and inhibition of plasminogen activator gene expression by hypoxia promotes pulmonary vascular fibrin deposition.

1998 ◽  
Vol 102 (5) ◽  
pp. 919-928 ◽  
Author(s):  
D J Pinsky ◽  
H Liao ◽  
C A Lawson ◽  
S F Yan ◽  
J Chen ◽  
...  
Keyword(s):  
Gene Expression ◽  
Plasminogen Activator ◽  
Plasminogen Activator Inhibitor ◽  
Fibrin Deposition ◽  
Plasminogen Activator Inhibitor 1 ◽  
Activator Inhibitor ◽  
Pai 1

scholarly journals Role of plasminogen activator inhibitor-1 in promoting fibrin deposition in rabbits infused with ancrod or thrombin

Blood ◽  
1993 ◽  
Vol 82 (12) ◽  
pp. 3631-3636 ◽  
Author(s):  
C Krishnamurti ◽  
C Bolan ◽  
CA Colleton ◽  
TM Reilly ◽  
BM Alving
Keyword(s):  
Plasminogen Activator ◽  
Plasminogen Activator Inhibitor ◽  
Fibrin Deposition ◽  
Plasminogen Activator Inhibitor 1 ◽  
Elevated Activity ◽  
Activator Inhibitor ◽  
Pai 1

The role of defective fibrinolysis caused by elevated activity of plasminogen activator inhibitor-1 (PAI-1) in promoting fibrin deposition in vivo has not been well established. The present study compared the efficacy of thrombin or ancrod, a venom-derived enzyme that clots fibrinogen, to induce fibrin formation in rabbits with elevated PAI-1 levels. One set of male New Zealand rabbits received intravenous endotoxin to increase endogenous PAI-1 activity followed by a 1-hour infusion of ancrod or thrombin; another set of normal rabbits received intravenous human recombinant PAI-1 (rPAI-1) during an infusion of ancrod or thrombin. Thirty minutes after the end of the infusion, renal fibrin deposition was assessed by histopathology. Animals receiving endotoxin, rPAI-1, ancrod, or thrombin alone did not develop renal thrombi. All endotoxin-treated rabbits developed fibrin deposition when infused with ancrod (n = 4) or thrombin (n = 6). Fibrin deposition occurred in 7 of 7 rabbits receiving both rPAI-1 and ancrod and in only 1 of 6 receiving rPAI-1 and thrombin (P “ .01). In vitro, thrombin but not ancrod was inactivated by normal rabbit plasma and by purified antithrombin III or thrombomodulin. The data indicate that elevated levels of PAI-1 promote fibrin deposition in rabbits infused with ancrod but not with thrombin. In endotoxin-treated rabbits, fibrin deposition that occurs with thrombin infusion may be caused by decreased inhibition of procoagulant activity and not increased PAI-1 activity.

Critical Roles of Rho Kinase and Mek/Erk Pathways for Angiotensin Ii-Induced Plasminogen Activator Inhibitor-1 Gene Expression

Hypertension ◽  
2000 ◽  
Vol 36 (suppl_1) ◽  
pp. 721-721
Author(s):  
Kotaro Takeda ◽  
Toshihiro Ichiki ◽  
Tomotake Tokunou ◽  
Satoshi Fujii ◽  
Akira Kitabatake ◽  
...  
Keyword(s):  
Gene Expression ◽  
Angiotensin Ii ◽  
Plasminogen Activator ◽  
Rho Kinase ◽  
Plasminogen Activator Inhibitor ◽  
Luciferase Assay ◽  
Ang Ii ◽  
Plasminogen Activator Inhibitor 1 ◽  
Activator Inhibitor ◽  
Pai 1

P157 Plasminogen activator inhibitor-1 (PAI-1) plays an integral role not only in the regulation of plasminogen activity and fibrinolytic system but also in the pathogenesis of atherosclerosis and hypertension. Because angiotensin II (Ang II) is also involved in these processes, we investigated its role in the intracellular signaling cascade leading to PAI-1 gene expression in vascular smooth muscle cells (VSMC). Ang II increased the PAI-1 mRNA and protein levels through Ang II type 1 receptor. Although PAI-1 mRNA stability was not increased by Ang II, PAI-1 gene promoter activity, which was measured by luciferase assay, was significantly increased by Ang II. This process did not require de novo protein synthesis. BAPTA-AM, genistein and AG1478 completely inhibited the Ang II-induced PAI-1 mRNA upregulation, suggesting that intracellular calcium, tyrosine kinase and epidermal growth factor (EGF) receptor transactivation were involved in this process. However, inhibition of protein kinase C (PKC) by calphostin C, GF109203, or prolonged exposure to PMA failed to abolish the Ang II-induced PAI-1 upregulation, suggesting PKC pathway was not involved. PD98059 suppressed Ang II-induced PAI-1 upregulation, whereas SB203580 did not, suggesting that MEK/ERK1/2 pathway rather than p38 MAP kinase pathway was crucial in this process. Furthermore, adenovirus-mediated expression of dominant negative form of Rho kinase or Rho kinase inhibitor Y27632 also completely suppressed PAI-1 induction by Ang II without affecting Ang II-induced ERK1/2 activation. These data suggest that activation of both MEK/ERK1/2 and Rho kinase pathways will be necessary for the upregulation of PAI-1 gene expression and these two pathways may act synergically to promote PAI-1 gene transcription at least at the downstream of ERK1/2 in VSMC. These findings are important biological and therapeutical implications for the evolution of arterial wall thrombus and the pathogenesis of atherosclerosis by Ang II.

scholarly journals Glucocorticoid-modulated gene expression of tissue- and urinary-type plasminogen activator and plasminogen activator inhibitor 1 and 2.

1988 ◽  
Vol 106 (3) ◽  
pp. 971-978 ◽  
Author(s):  
R L Medcalf ◽  
E Van den Berg ◽  
W D Schleuning
Keyword(s):  
Gene Expression ◽  
Plasminogen Activator ◽  
Protein Biosynthesis ◽  
Plasminogen Activator Inhibitor ◽  
Tissue Type ◽  
Northern Blot Hybridization ◽  
Plasminogen Activator Inhibitor 1 ◽  
Type Plasminogen Activator ◽  
Activator Inhibitor ◽  
Pai 1

Constitutive gene expression of four components of plasminogen activating enzyme system, urinary and tissue-type plasminogen activator (u-PA and t-PA), plasminogen activator inhibitor 1 (PAI-1) and PAI-2 in HT-1080 human fibrosarcoma cells, was modulated by the synthetic glucocorticoid dexamethasone (Dex, 10(-7) M). More than 90% of u-PA, t-PA and PAI-1 antigen was found in conditioned medium, whereas PAI-2 was mainly cell associated. In 48-h culture supernatants (expressed per 10(6) cells) PAI-1 antigen increased from 350 to 3,300 ng and t-PA from 19 to 38 ng. u-PA and PAI-2 in the same samples decreased from 380 to 46 ng and from 3.5 to 1.8 ng, respectively. Northern blot hybridization and nuclear "Run-on" transcription assays demonstrated that the increase of t-PA and PAI-1 and the decrease of u-PA were associated with equivalent changes of gene template activity. Modulation of u-PA, t-PA and PAI-1 gene expression by Dex was completely blocked by the glucocorticoid antagonist RU 38486, suggesting that all effects were mediated through the glucocorticoid receptor. Cycloheximide, an inhibitor of protein biosynthesis induced a rapid transient increase of t-PA, u-PA and PAI-1 mRNA and a sustained increase of PAI-2 mRNA, but blocked the more long term effects of Dex, suggesting that both constitutive and hormonally regulated maintenance of mRNA steady state levels required protein biosynthesis.

scholarly journals Endogenous Aldosterone Contributes to Acute Angiotensin II-Stimulated Plasminogen Activator Inhibitor-1 and Preproendothelin-1 Expression in Heart But Not Aorta

Endocrinology ◽  
2008 ◽  
Vol 150 (5) ◽  
pp. 2229-2236 ◽  
Author(s):  
James M. Luther ◽  
Zuofei Wang ◽  
Ji Ma ◽  
Natalia Makhanova ◽  
Hyung-Suk Kim ◽  
...  
Keyword(s):  
Gene Expression ◽  
Mrna Expression ◽  
Plasminogen Activator ◽  
Plasma Renin ◽  
Plasminogen Activator Inhibitor ◽  
Renin Activity ◽  
Ang Ii ◽  
Plasminogen Activator Inhibitor 1 ◽  
Activator Inhibitor ◽  
Pai 1

To test the hypothesis that angiotensin (Ang) II induces profibrotic gene expression through endogenous aldosterone, we measured the effect of 4 h infusion (600 ng/kg · min) of Ang II on tissue mRNA expression of plasminogen activator inhibitor 1 (PAI-1), preproendothelin-1 (ppET-1), TGF-β, and osteopontin in wild-type (WT), aldosterone synthase-deficient (AS−/−), and AS−/− mice treated with aldosterone (either 500 ng/d for 7 d or 250 ng as a concurrent 4 h infusion). Ang II increased aldosterone in WT (P < 0.001) but not in AS−/− mice. Aldosterone (7 d) normalized basal aldosterone concentrations in AS−/− mice; however, there was no further effect of Ang II on aldosterone (P = NS). Basal cardiac and aortic PAI-1 and ppET-1 expression were similar in WT and AS−/− mice. Ang II-stimulated PAI-1 (P < 0.001) and ppET-1 expression (P = 0.01) was diminished in the heart of AS−/− mice; treatment with aldosterone for 4 h or 7 d restored PAI-1 and ppET-1 mRNA responsiveness to Ang II in the heart. Ang II increased PAI-1 (P = 0.01) expression in the aorta of AS−/− as well as WT mice. In the kidney, basal PAI-1, ppET-1, and TGF-β mRNA expression was increased in AS−/− compared with WT mice and correlated with plasma renin activity. Ang II did not stimulate osteopontin or TGF-β expression in the heart or kidney. Endogenous aldosterone contributes to the acute stimulatory effect of Ang II on PAI-1 and ppET-1 mRNA expression in the heart; renin activity correlates with basal profibrotic gene expression in the kidney.

Hypoxia-inducible factor-1 and hypoxia response elements mediate the induction of plasminogen activator inhibitor-1 gene expression by insulin in primary rat hepatocytes

Blood ◽  
2003 ◽  
Vol 101 (3) ◽  
pp. 907-914 ◽  
Author(s):  
Thomas Kietzmann ◽  
Anatoly Samoylenko ◽  
Ulrike Roth ◽  
Kurt Jungermann
Keyword(s):  
Gene Expression ◽  
Plasminogen Activator ◽  
Hypoxia Inducible Factor ◽  
Plasminogen Activator Inhibitor ◽  
Plasminogen Activator Inhibitor 1 ◽  
Hypoxia Response ◽  
Response Elements ◽  
Hypoxia Inducible Factor 1 ◽  
Activator Inhibitor ◽  
Pai 1

AbstractThe expression of the plasminogen activator inhibitor-1(PAI-1) gene is enhanced by insulin both in vivo and in various cell types. Because insulin exerts a number of its biologic activities via the phosphatidylinositol 3-kinase and protein kinase B (PI3K/PKB) signaling pathway, it was the aim of the present study to investigate the role of the PI3K/PKB pathway in the expression of the PAI-1 gene and to identify the insulin responsive promoter sequences. It was shown that the induction of PAI-1 mRNA and protein expression by insulin and mild hypoxia could be repressed by the PI3K inhibitor wortmannin. Overexpression of a constitutively active PKB led to induction of PAI-1 mRNA expression and of luciferase (Luc) activity from a gene construct containing 766 bp of the rat PAI-1 promoter. Mutation of the hypoxia response elements (HRE-1 and HRE-2) in rat PAI-1 promoter, which could bind hypoxia inducible factor-1 (HIF-1), abolished the induction of PAI-1 by insulin and PKB. Insulin and the constitutive active PKB also induced Luc expression in cells transfected with the pGl3EPO-HRE Luc construct, containing 3 copies of the HRE from the erythropoietin gene in front of the SV40 promoter. Furthermore, insulin and the active PKB enhanced all 3 HIF α-subunit protein levels and HIF-1 DNA-binding activity, as shown by electrophoretic mobility shift assays (EMSAs). Thus, the insulin-dependent activation of the PAI-1 gene expression can be mediated via the PI3K/PKB pathway and the transcription factor HIF-1 binding to the HREs in the PAI-1 gene promoter.

scholarly journals Prevention of Renal Fibrin Deposition in Endotoxin-induced DIC through Inhibition of PAI-1

2000 ◽  
Vol 84 (07) ◽  
pp. 65-70 ◽  
Author(s):  
Ramón Montes ◽  
Paul Declerck ◽  
Alfonso Calvo ◽  
Marta Montes ◽  
José Hermida ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Plasminogen Activator ◽  
Disseminated Intravascular Coagulation ◽  
Plasminogen Activator Inhibitor ◽  
Control Group ◽  
Fibrin Deposition ◽  
Plasminogen Activator Inhibitor 1 ◽  
Activator Inhibitor ◽  
Pai 1

SummaryPlasminogen activator inhibitor-1 (PAI-1) increases in endotoxemia thus possibly cooperating in altering the hemostatic balance in a prothrombotic direction. The effect of the inhibition of PAI-1 with the monoclonal antibody MA-33B8 was studied systemically and in kidneys in a lapine model of endotoxin-induced disseminated intravascular coagulation (DIC). The increase in plasmatic PAI activity in the control group (n = 9) was inhibited in the MA-33B8 treated rabbits (n = 5). Control rabbits showed renal fibrin deposits, whereas only one of the MA-33B8 rabbits did so. These results were confirmed immunohistochemically in kidneys as PAI-1 immunostaining was seen inside the glomeruli and larger vessels in the control group, whereas MA-33B8 rabbits showed a remarkable decrease, demonstrating that MA-33B8 successfully inhibited PAI-1 in the kidneys as well. Therefore evidence for the important role of PAI-1 in fibrin generation in endotoxin-induced DIC is presented, suggesting that strategies aiming at its reduction can be useful in this pathology.

scholarly journals Role of plasminogen activator inhibitor-1 in promoting fibrin deposition in rabbits infused with ancrod or thrombin

Blood ◽  
1993 ◽  
Vol 82 (12) ◽  
pp. 3631-3636 ◽  
Author(s):  
C Krishnamurti ◽  
C Bolan ◽  
CA Colleton ◽  
TM Reilly ◽  
BM Alving
Keyword(s):  
Plasminogen Activator ◽  
Plasminogen Activator Inhibitor ◽  
Fibrin Deposition ◽  
Plasminogen Activator Inhibitor 1 ◽  
Elevated Activity ◽  
Activator Inhibitor ◽  
Pai 1

Abstract The role of defective fibrinolysis caused by elevated activity of plasminogen activator inhibitor-1 (PAI-1) in promoting fibrin deposition in vivo has not been well established. The present study compared the efficacy of thrombin or ancrod, a venom-derived enzyme that clots fibrinogen, to induce fibrin formation in rabbits with elevated PAI-1 levels. One set of male New Zealand rabbits received intravenous endotoxin to increase endogenous PAI-1 activity followed by a 1-hour infusion of ancrod or thrombin; another set of normal rabbits received intravenous human recombinant PAI-1 (rPAI-1) during an infusion of ancrod or thrombin. Thirty minutes after the end of the infusion, renal fibrin deposition was assessed by histopathology. Animals receiving endotoxin, rPAI-1, ancrod, or thrombin alone did not develop renal thrombi. All endotoxin-treated rabbits developed fibrin deposition when infused with ancrod (n = 4) or thrombin (n = 6). Fibrin deposition occurred in 7 of 7 rabbits receiving both rPAI-1 and ancrod and in only 1 of 6 receiving rPAI-1 and thrombin (P “ .01). In vitro, thrombin but not ancrod was inactivated by normal rabbit plasma and by purified antithrombin III or thrombomodulin. The data indicate that elevated levels of PAI-1 promote fibrin deposition in rabbits infused with ancrod but not with thrombin. In endotoxin-treated rabbits, fibrin deposition that occurs with thrombin infusion may be caused by decreased inhibition of procoagulant activity and not increased PAI-1 activity.

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