Disease relevance of SERPINE1

• Urokinase-type plasminogen activator and its inhibitor PAI-1: predictors of poor response to tamoxifen therapy in recurrent breast cancer [1].
• Its activity during metastasis may be regulated by an inhibitor, PAI-1 [1].
• We hypothesized that therapy with a mutant human PAI-1 (PAI-1R) that binds to matrix vitronectin but does not inhibit plasminogen activators, would enhance plasmin generation, increase matrix turnover, and decrease matrix accumulation in experimental glomerulonephritis [2].
• The decrease in t-PA activity in the neoplastic tissues, determined enzymatically and zymographically, was significantly correlated with an increase in PAI-1 and PAI-2, in particular in carcinomas [3].
• The deposition of both PAI-1 and fibronectin by the sarcoma cells was enhanced, after treating the cells with 10(-6) M dexamethasone [4].
• Similar increases in thrombus lysis were observed on inclusion of neutralizing antibodies to PAI-1 and alpha(2)AP, with alpha(2)AP playing the dominant role [5].
• Likewise, the association between the FGB A allele and GMT was restricted to lupus nephritis patients homozygous for the PAI-1 4G allele [6].
• Our data show a correlation between the 4G4G genotype of the PAI-1 gene and development of DIC in meningococcal infection [7].
• These recent findings emphasize the involvement of PAI-1 in controlling the biology of adipose tissue; PAI-1 is an attractive new therapeutic target to retard the metabolic complications that accompany obesity [8].
• The deletion of the PAI-1 gene reduces, whereas the overexpression of PAI-1 enhances, the susceptibility of animals to lung fibrosis induced by different stimuli, indicating an important role of PAI-1 in the development of lung fibrosis [9].

Psychiatry related information on SERPINE1

• Only individual patients with severe AIDS dementia complex had increased levels of uPA (but not PAI-1) which fell upon initiation of antiretroviral therapy [10].
• This suggests that the impact of apoE4 on Alzheimer's disease is not the result of altered clearance of tPA or PAI-1 by the LRP receptor [11].
• RESULTS: PAI-1 levels were significantly lower in American than in Japanese men, even after adjustment for age, waist girth, cigarette smoking, habitual alcohol drinking, and other factors [12].
• Examination included physique measurement (BMI and waist girth), blood analysis (lipid profiles, glucose, insulin, C-reactive protein, and PAI-1), and life-style assessment by self-administered questionnaires [12].
• It is possible to reduce plasma PAI-1 by changes in life style, e.g. weight reduction and physical activity [13].

High impact information on SERPINE1

• The concentration of t-PA antigen correlated with that of the t-PA-PAI-1 complex in a linear regression model (squared correlation coefficient, 0.80; P<0.001) [14].
• BACKGROUND: Plasma levels of plasminogen-activator inhibitor type 1 (PAI-1), an essential inhibitor of fibrinolysis in humans, increase in women after menopause, and this may contribute to the risk of cardiovascular disease [15].
• Transdermal estradiol caused no significant changes in PAI-1 levels from base-line values [15].
• CONCLUSIONS: Conjugated estrogen, alone or combined with progestin therapy, reduced PAI-1 levels by approximately 50 percent in postmenopausal women and was associated with enhanced systemic fibrinolysis [15].
• METHODS: In a randomized, crossover study, we investigated the effects of oral conjugated estrogen (0.625 mg per day) in 30 postmenopausal women and transdermal estradiol (0.1 mg per day) in 20 postmenopausal women, either alone or in combination with medroxyprogesterone acetate (2.5 mg daily) for one month, on plasma PAI-1 antigen levels [15].

Chemical compound and disease context of SERPINE1

• To determine whether pharmacological concentrations of gemfibrozil directly affect PAI-1 synthesis, we characterized its effects on a human hepatoma cell line (Hep G2) in vitro [16].
• To this end PAI-1 was purified from cortisol-stimulated HT 1080 fibrosarcoma cells and antisera raised in rabbits [17].
• It was shown that the Ca(2+)-ionophore A23187 and the cell permeable Ca(2+)-chelator BAPTA-am (1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid-acetoxymethyl ester) induced PAI-1 mRNA and protein expression under normoxia and hypoxia in HepG2 cells [18].
• Serine proteinase inhibitors, including plasminogen activator inhibitor type 1 (PAI-1) and antithrombin, are key regulators of hemostatic processes such as thrombosis and wound healing [19].
• Its effects on ROS production, AP-1 activity, plasminogen activator inhibitor 1 (PAI-1) gene expression, and cellular proliferation and migration were measured in response to high glucose and angiotensin II (Ang II) concentrations, two major factors in the pathogenesis of atherosclerosis in patients with diabetes and hypertension [20].

Biological context of SERPINE1

• We provide evidence that this balance between cell adhesion and cell detachment is governed by PA inhibitor-1 (PAI-1) [21].
• Transfection experiments demonstrate that efficient cell detachment by PAI-1 requires an excess of matrix-engaged uPA-uPAR-integrin complexes over free engaged integrins and that changes in this ratio alter the efficacy of PAI-1 [22].
• Domain swapping and mutagenesis studies indicate that the uPAR-binding sequence is located within the central region of the SMB domain, a region previously shown to contain the PAI-1-binding motif [21].
• Beneficial effects of gemfibrozil in reducing coronary events in hypertriglyceridemic patients may depend, in part, on potentiation of fibrinolysis by direct diminution of synthesis of endogenous PAI-1 [16].
• Thus acquisition of sensitivity to PAI-1 through a structural motif that enhances the specificity of the protease-inhibitor interaction confers to ch-uPA an added level of regulation in the context of the degradative cellular phenotype [23].

Anatomical context of SERPINE1

• Association of a plasminogen activator inhibitor (PAI-1) with the growth substratum and membrane of human endothelial cells [24].
• We have studied the mechanism of a transforming growth factor-beta (TGF-beta)-stimulated production of type-1 plasminogen activator inhibitor (PAI-1) in WI-38 human lung fibroblasts [25].
• We have studied the distribution of the plasminogen activator inhibitor type 1 (PAI-1) in cultures of confluent human umbilical vein endothelial cells [24].
• U937 cells were incubated at 4 degrees C with labeled uPA-PAI-1 (and other ligands), the temperature then raised to 37 degrees C and the fate of the ligand followed for 3 h thereafter [26].
• The rapid deposition and predominance of PAI-1 in the underlying compartment of endothelial cells may explain how the basement membrane is protected from proteolytic degradation by plasmin-generating enzymes [24].

Associations of SERPINE1 with chemical compounds

• TGF-beta signals through type I and II receptor serine/ threonine kinases and induces transcription of many genes including plasminogen activator inhibitor-1 (PAI-1) [27].
• The association of PAI-1 expression and the response to tamoxifen was less pronounced when patients were stratified by ER/PgR status [1].
• Blocking of protein synthesis with cycloheximide causes an equally strong increase in the level of PAI-1 mRNA [25].
• The degradation of the uPA-PAI-1 complex is preceded by internalization and is inhibited by chloroquine, an inhibitor of lysosomal protein degradation [26].
• This MRE sequence mediated a 4-fold increase of MEK1,2-dependent PAI-1/luciferase mRNA expression by angiotensin II stimulation [28].
• Antagonists of the alphavbeta5 integrin mimicked the effect of PAI1 on cell morphology and fibronectin matrix deposition, indicating that stimulation of matrix assembly by PAI1 required disruption of the interaction between the alphavbeta5 integrin and vitronectin [29].

Physical interactions of SERPINE1

• Receptor bound active uPA can also interact with its specific type 1 inhibiror (PAI-1) which is therefore able to inhibit the cell surface plasmin formation [26].
• This pathway may represent a general mechanism, since PAI-1 also can detach cells from fibronectin and type-1 collagen [22].
• The identification of platelet VN and its binding to platelet PAI-1 raises the possibility that VN, in contrast to other adhesive proteins, may participate in localized regulatory functions of blood coagulation and fibrinolysis in platelet-matrix interactions and the protection of the matrix against proteolysis [30].
• Several findings suggest that PAI-1 is a major binding site for S478A t-PA [31].
• The effect of Smad6s on the PAI-1 promoter appeared to be the result of increase binding of the forkhead winged helix factor FoxD1 to a TGF-beta-responsive element [32].

Enzymatic interactions of SERPINE1

• HNE cleaved active PAI-1 and produced low molecular weight forms of inactive PAI-1, as previously reported [33].
• A stabilized active PAI-1 variant was also cleaved by MMP-3 [34].
• Detailed interpretation of the (19)F NMR spectra of the PAI-1 mutants provides insights into the local segmental structure of the active form of the proteins and the structural changes that occur in the cleaved and t-PA complexed forms [35].
• Accordingly, PAI-1 was recovered in a reactive-centre-cleaved form from incubations with urokinase-type plasminogen activator (uPA) and tissue-type plasminogen activator (tPA) at 0 degree C, but not at 37 degrees C. It thus behaved as a substrate for the target proteinases at the lower temperature [36].

Co-localisations of SERPINE1

• CLSM image analysis confirmed that the b-Vn was internalized and that it colocalized with PAI-1 in storage granules [37].

Regulatory relationships of SERPINE1

• Our results demonstrate that PAI-1 may regulate uPA-initiated cell signaling by a mechanism that requires VLDLr recruitment [38].
• Human plasminogen activator inhibitor-1 (PAI-1) is a gene that is potently induced by TGF beta [39].
• The basic helix-loop-helix leucine zipper (bHLHZIP) protein TFE3 and Smad3 synergistically activate transcription of the plasminogen activator inhibitor-1 (PAI-1) as well as other genes [40].
• Binding of PAI-1 to endothelial cells stimulated by thymosin beta4 and modulation of their fibrinolytic potential [41].
• Finally, kinetic modeling demonstrated that acylation is the rate-limiting step in thrombin inhibition by PAI-1 (k approximately 10(-3) s(-1)) and this kinetic block is alleviated by the introduction of the tPA-VR1 into thrombin (k>1 s(-1)) [42].
• These data indicate that extracellular RNA and PAI-1 can regulate FSAP activity, thereby playing a potentially important role in hemostasis and cell functions under various pathophysiological conditions, such as acute respiratory distress syndrome [43].

Other interactions of SERPINE1

• In addition, patients with uPA-positive or PAI-1-positive tumors showed shorter progression-free survival (P = .001 and P < .05, respectively) and total survival after relapse (P = .005 and P < .005, respectively) [1].
• Together, these results suggest a VN-independent, uPA-uPAR-dependent mechanism by which PAI-1 induces cell detachment [22].
• This was the result of an increase of PAI-1 antigen; PAI-2 antigen was not detectable [44].
• The cleavage and inactivation of PAI-1 by HNE was shown to be a novel pathway to enhance fibrinolysis [33].
• Nur77 drives transcription of PAI-1 through direct binding to an NGFI-B responsive element (NBRE), indicating monomeric binding and a ligand-independent mechanism [45].

Analytical, diagnostic and therapeutic context of SERPINE1

• Immunoprecipitation and subcellular fractionation experiments reveal that PAI-1 treatment triggers deactivation and disengagement of uPA-uPAR-integrin complexes and their endocytic clearance by the low density lipoprotein receptor-related protein [22].
• We further demonstrated the deposition of u-PA to the contact areas of cells obtained by saponin treatment by zymography, and that of PAI-1 by metabolic labeling, reverse zymography, immunoblotting, and immunoprecipitation [4].
• Immuno-electron microscopy confirmed the plasma membrane to intracellular translocation of uPAR, and its dependence on LRP/alpha 2-MR in LB6 clone 19 cells only after binding to the uPA-PAI-1 complex [46].
• PAI-1 mRNA and protein expression were seen in human coronary artery atherectomy specimens as well and were localized to analogous monocyte/macrophages and to smooth muscle cells as judged from results of in situ hybridization and immunocytochemistry studies [47].
• BACKGROUND: In patients with established ischemic heart disease, prospective cohort studies have indicated that plasminogen activator inhibitor (PAI-1), the inhibitor of the fibrinolytic system, may predict cardiovascular events [48].

References