Plasminogen activator inhibitor-1: a potential etiological role in livedoid vasculopathy.
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ABSTRACT:
SUBMITTER: Gao Y
PROVIDER: S-EPMC7948802 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:BackgroundProtein levels of urokinase plasminogen activator (uPA) and its inhibitor (PAI-1) determined by enzyme-linked immunosorbent assay from fresh-frozen tumor tissue have been evaluated as prognostic factors in prospectively randomized trials in breast cancer. However, the role of uPA and PAI-1 in the context of breast cancer subtypes and for mRNA expression of these factors is less clear.MethodsWe evaluated uPA and PAI-1 mRNA expression using the Affymetrix HG-U 133A array within molecular subgroups of breast cancer in cohorts of patients with systemic treatment (cohort A, n=362) and without systemic treatment (cohort B, n=200). We validated mRNA expression in a cohort of HER2-positive breast cancer patients (cohort C, n=290). Luminal, triple-negative, and HER2-positive subcohorts were defined by ESR1 and ERBB2 mRNA expression using predefined cutoffs.ResultsIn the entire cohort A, elevated PAI-1 but not uPA mRNA expression was associated with shorter disease-free survival (P=0.007 for PAI and 0.069 for uPA). Regarding different molecular subgroups, 67% (n=244) of tumors were luminal, 14% (n=49) were HER2-positive, and 19% (n=69) were triple-negative. Elevated PAI-1 mRNA expression was associated with shorter disease-free survival only in the HER2-positive subgroup (P=0.031). The same disease-free survival results were found for uPA in HER2-positive patients (P=0.011). In contrast, no association between either marker and survival was observed in the luminal or triple-negative subgroups. In the HER2-positive validation cohort C, elevated uPA and PAI-1 mRNA expression also showed strong associations with shorter disease-free survival (P=0.014 for PAI-1, P<0.001 for uPA).ConclusionIn this study, the prognostic impact of uPA and PAI-1 expression was mainly observed in patients with HER2-positive tumors.
| S-EPMC4259258 | biostudies-literature
Project description:Plasminogen activator inhibitor-1 (PAI-1), together with its physiological target urokinase-type plasminogen activator (uPA), plays a pivotal role in fibrinolysis, cell migration, and tissue remodeling and is currently recognized as being among the most extensively validated biological prognostic factors in several cancer types. PAI-1 specifically and rapidly inhibits uPA and tissue-type PA (tPA). Despite extensive structural/functional studies on these two reactions, the underlying structural mechanism has remained unknown due to the technical difficulties of obtaining the relevant structures. Here, we report a strategy to generate a PAI-1·uPA(S195A) Michaelis complex and present its crystal structure at 2.3-? resolution. In this structure, the PAI-1 reactive center loop serves as a bait to attract uPA onto the top of the PAI-1 molecule. The P4-P3' residues of the reactive center loop interact extensively with the uPA catalytic site, accounting for about two-thirds of the total contact area. Besides the active site, almost all uPA exosite loops, including the 37-, 60-, 97-, 147-, and 217-loops, are involved in the interaction with PAI-1. The uPA 37-loop makes an extensive interaction with PAI-1 ?-sheet B, and the 147-loop directly contacts PAI-1 ?-sheet C. Both loops are important for initial Michaelis complex formation. This study lays down a foundation for understanding the specificity of PAI-1 for uPA and tPA and provides a structural basis for further functional studies.
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Project description:Patients with coronavirus disease-19 (COVID-19) are at high risk for thrombotic arterial and venous occlusions. However, bleeding complications have also been observed in some patients. Understanding the balance between coagulation and fibrinolysis will help inform optimal approaches to thrombosis prophylaxis and potential utility of fibrinolytic-targeted therapies. 118 hospitalized COVID-19 patients and 30 healthy controls were included in the study. We measured plasma antigen levels of tissue-type plasminogen activator (tPA) and plasminogen activator inhibitor-1 (PAI-1) and performed spontaneous clot-lysis assays. We found markedly elevated tPA and PAI-1 levels in patients hospitalized with COVID-19. Both factors demonstrated strong correlations with neutrophil counts and markers of neutrophil activation. High levels of tPA and PAI-1 were associated with worse respiratory status. High levels of tPA, in particular, were strongly correlated with mortality and a significant enhancement in spontaneous ex vivo clot-lysis. While both tPA and PAI-1 are elevated among COVID-19 patients, extremely high levels of tPA enhance spontaneous fibrinolysis and are significantly associated with mortality in some patients. These data indicate that fibrinolytic homeostasis in COVID-19 is complex with a subset of patients expressing a balance of factors that may favor fibrinolysis. Further study of tPA as a biomarker is warranted.
| S-EPMC7810990 | biostudies-literature
Project description:Plasminogen activator inhibitor-1 (PAI-1) is known to protect mice against cardiac fibrosis. It has been speculated that PAI-1 may regulate cardiac fibrosis by inactivating urokinase-type plasminogen activator (uPA) and ultimately plasmin (Pm) generation. However, the in vivo role of PAI-1 in inactivating uPA and limiting the generation of Pm during cardiac fibrosis remains to be established. The objective of this study was to determine if the cardioprotective effect of PAI-1 is mediated through its ability to directly regulate urokinase -mediated activation of plasminogen (Pg). An Angiotensin II (AngII)-aldosterone (Ald) infusion mouse model of hypertension was utilised in this study. Four weeks after AngII-Ald infusion, PAI-1-deficient (PAI-1-/-) mice developed severe cardiac fibrosis. However, a marked reduction in cardiac fibrosis was observed in PAI-1-/-/uPA-/- double knockout mice that was associated with reduced inflammation, lower expression levels of TGF-β and proteases associated with tissue remodeling, and diminished Smad2 signaling. Moreover, total ablation of cardiac fibrosis was observed in PAI-1-/- mice that express inactive plasmin (Pm) but normal levels of zymogen Pg (PAI-1-/-/PgS743A/S743A). Our findings indicate that PAI-1 protects mice from hypertension-induced cardiac fibrosis by inhibiting the generation of active Pm.
| S-EPMC5428408 | biostudies-literature
Project description:Due to controversial evidence in the literature pertaining to the activity of plasminogen activator inhibitor-1 in platelets, we examined the effects of residual platelets present in plasma (a potential pre-analytical variable) on various plasminogen activator inhibitor-1 and plasminogen activator inhibitor-1-related assays. Blood samples were collected from 151 individuals and centrifuged at 352 and 1500 g to obtain plasma with varying numbers of platelet. In a follow-up study, blood samples were collected from an additional 23 individuals, from whom platelet-poor (2000 g), platelet-containing (352 g) and platelet-rich plasma (200 g) were prepared and analysed as fresh-frozen and after five defrost-refreeze cycles (to determine the contribution of in vitro platelet degradation). Plasminogen activator inhibitor-1 activity, plasminogen activator inhibitor-1 antigen, tissue plasminogen activator/plasminogen activator inhibitor-1 complex, plasma clot lysis time, β-thromboglobulin and plasma platelet count were analysed. Platelet α-granule release (plasma β-thromboglobulin) showed a significant association with plasminogen activator inhibitor-1 antigen levels but weak associations with plasminogen activator inhibitor-1 activity and a functional marker of fibrinolysis, clot lysis time. Upon dividing the study population into quartiles based on β-thromboglobulin levels, plasminogen activator inhibitor-1 antigen increased significantly across the quartiles while plasminogen activator inhibitor-1 activity and clot lysis time tended to increase in the 4th quartile only. In the follow-up study, plasma plasminogen activator inhibitor-1 antigen was also significantly influenced by platelet count in a concentration-dependent manner. Plasma plasminogen activator inhibitor-1 antigen levels increased further after complete platelet degradation. Residual platelets in plasma significantly influence plasma plasminogen activator inhibitor-1 antigen levels mainly through release of latent plasminogen activator inhibitor-1 with limited effects on plasminogen activator inhibitor-1 activity, tissue plasminogen activator/plasminogen activator inhibitor-1 complex or plasma clot lysis time. Platelets may however also have functional effects on plasma fibrinolytic potential in the presence of high platelet counts, such as in platelet-rich plasma.
| S-EPMC5291504 | biostudies-literature
Project description:Plasminogen activator inhibitor-1 (PAI-1) is the main inhibitor of plasminogen activators, such as tissue-type plasminogen activator (t-PA) and urokinase-type plasminogen activator (u-PA), and a major regulator of the fibrinolytic system. PAI-1 plays a pivotal role in acute thrombotic events such as deep vein thrombosis (DVT) and myocardial infarction (MI). The biological effects of PAI-1 extend far beyond thrombosis including its critical role in fibrotic disorders, atherosclerosis, renal and pulmonary fibrosis, type-2 diabetes, and cancer. The conversion of PAI-1 from the active to the latent conformation appears to be unique among serpins in that it occurs spontaneously at a relatively rapid rate. Latency transition is believed to represent a regulatory mechanism, reducing the risk of thrombosis from a prolonged antifibrinolytic action of PAI-1. Thus, relying solely on plasma concentrations of PAI-1 without assessing its function may be misleading in interpreting the role of PAI-1 in many complex diseases. Environmental conditions, interaction with other proteins, mutations, and glycosylation are the main factors that have a significant impact on the stability of the PAI-1 structure. This review provides an overview on the current knowledge on PAI-1 especially importance of PAI-1 level and stability and highlights the potential use of PAI-1 inhibitors for treating cardiovascular disease.
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Project description:Oral squamous cell carcinoma (OSCC) is often associated with metastatic disease and a poor 5 year survival rate. Patients diagnosed with small tumours generally have a more favourable outcome, but some of these small tumours are aggressive and lead to early death. To avoid harmful overtreatment of patients with favourable prognosis, there is a need for predictive biomarkers that can be used for treatment stratification. In this study we assessed the possibility to use components of the plasminogen activator (PA) system as prognostic markers for OSCC outcome and compared this to the commonly used biomarker Ki-67. A tissue-micro-array (TMA) based immunohistochemical analysis of primary tumour tissue obtained from a North Norwegian cohort of 115 patients diagnosed with OSCC was conducted. The expression of the biomarkers was compared with clinicopathological variables and disease specific death. The statistical analyses revealed that low expression of uPAR (p = 0.031) and PAI-1 (p = 0.021) in the tumour cells was significantly associated with low disease specific death in patients with small tumours and no lymph node metastasis (T1N0). The commonly used biomarker, Ki-67, was not associated with disease specific death in any of the groups of patients analysed. The conclusion is that uPAR and PAI-1 are potential predictive biomarkers in early stage tumours and that this warrants further studies on a larger cohort of patients.
| S-EPMC4084992 | biostudies-literature
Project description:Livedoid vasculopathy (LV) is considered a disease of hypercoagulability. Association of LV with genetic variants is poorly characterised and large-scale genetic association studies have not been performed. The aim of the study was to systematically review variants in LV patients and to analyse the available clinical data. A systematic search of the literature in PubMed and Embase databases was performed to identify articles investigating genetic variation in LV patients. Thirty studies or case reports were identified that reported 265 LV patients tested for at least one out of six genetic variations. Among them, PAI-1 -675 4G/5G was the most common, accounting for 85.26% (81/95). Heterozygous 4G/5G was the major genotype. PAI-1 A844G, MTHFR C677T, and MTHFR A1298C were the second, third, and fourth most common variants in LV patients. Prothrombin G20210A and Factor V G1691A were mainly present in LV patients from Europe, North America, and South America. This review highlights the associations between LV and genetic variants. The distribution of variants may be geographically or ethnicity dependent; however, large sample case-control studies are needed to clarify associations.
| S-EPMC8450804 | biostudies-literature
Project description:Plasminogen activator inhibitor-1 (PAI-1) is a biomarker for several vascular disease states; however, its target of action within the vessel wall is undefined.Determine the ability of PAI-1 to regulate myoendothelial junction (MEJ) formation.MEJs are found throughout the vasculature linking endothelial cells (ECs) and vascular smooth muscle cells. Using a vascular cell coculture we isolated MEJ fractions and performed two-dimensional differential gel electrophoresis. Mass spectrometry identified PAI-1 as being enriched within MEJ fractions, which we confirmed in vivo. In the vascular cell coculture, recombinant PAI-1 added to the EC monolayer significantly increased MEJs. Conversely, addition of a PAI-1 monoclonal antibody to the EC monolayer reduced the number of MEJs. This was also observed in vivo where mice fed a high fat diet had increased PAI-1 and MEJs and the number of MEJs in coronary arterioles of PAI-1(-/-) mice was significantly reduced when compared to C57Bl/6 mice. The presence of MEJs in PAI-1(-/-) coronary arterioles was restored when their hearts were transplanted into and exposed to the circulation of C57Bl/6 mice. Application of biotin-conjugated PAI-1 to the EC monolayer in vitro confirmed the ability of luminal PAI-1 to translocate to the MEJ. Functionally, phenylephrine-induced heterocellular calcium communication in the vascular cell coculture was temporally enhanced when recombinant PAI-1 was present, and prolonged when PAI-1 was absent.Our data implicate circulating PAI-1 as a key regulator of MEJ formation and a potential target for pharmacological intervention in diseases with vascular abnormalities (eg, diabetes mellitus).
| S-EPMC2848897 | biostudies-literature
Project description:The molecular mechanisms underlying cerebral angiogenesis have not been fully investigated. Using primary mouse brain endothelial cells (MBECs) and a capillary-like tube formation assay, we investigated whether the sonic hedgehog (Shh) signaling pathway is coupled with the plasminogen/plasmin system in mediating cerebral angiogenesis. We found that incubation of MBECs with recombinant human Shh (rhShh) substantially increased the tube formation in naïve MBECs. This was associated with increases in tissue plasminogen activator (tPA) activation and reduction of plasminogen activator inhibitor 1 (PAI-1). Blockage of the Shh pathway with cyclopamine abolished the induction of tube formation and the effect of rhShh on tPA and PAI-1. Addition of PAI-1 reduced rhShh-augmented tube formation. Genetic ablation of tPA in MBECs impaired tube formation and downregulated of vascular endothelial growth factor (VEGF) and angiopoietin 1 (Ang1). Addition of rhShh to tPA-/- MBECs only partially restored the tube formation and upregulated Ang1, but not VEGF, although rhShh increased VEGF and Ang1 expression on wild-type MBECs. Complete restoration of tube formation in tPA-/- MBECs was observed only when both exogenous Shh and tPA were added. The present study provides evidence that tPA and PAI-1 contribute to Shh-induced in vitro cerebral angiogenesis.
| S-EPMC3303815 | biostudies-literature