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Haematologica Feb 2021Tissue plasminogen activator (tPA) and urokinase (uPA) differ in their modes of action. Efficient tPA-mediated plasminogen activation requires binding to fibrin. In...
Tissue plasminogen activator (tPA) and urokinase (uPA) differ in their modes of action. Efficient tPA-mediated plasminogen activation requires binding to fibrin. In contrast, uPA is fibrin independent and activates plasminogen in solution or when associated with its cellular receptor uPAR. We have previously shown that polyphosphate (polyP), alters fibrin structure and attenuates tPA and plasminogen binding to fibrin, thereby down-regulating fibrinolysis. Here we investigate the impact of polyP on uPA-mediated fibrinolysis. As previously reported polyP of an average chain length of 65 (polyP65) delays tPA-mediated fibrinolysis. The rate of plasmin generation was also delayed and reduced 1.6-fold in polyP65-containing clots (0.74 ± 0.06 vs. 1.17 ± 0.14 pM/s in P < 0.05). Analysis of tPA-mediated fibrinolysis in real-time by confocal microscopy was significantly slower in polyP65-containing clots. In marked contrast, polyP65 augmented the rate of uPA-mediated plasmin generation 4.7-fold (3.96 ± 0.34 vs. 0.84 ± 0.08 pM/s; P < 0.001) and accelerated fibrinolysis (t1/2 64.5 ± 1.7 min vs. 108.2 ± 3.8 min; P < 0.001). Analysis of lysis in real-time confirmed that polyP65 enhanced uPA-mediated fibrinolysis. Varying the plasminogen concentration (0.125 to 1 μM) in clots dose-dependently enhanced uPA-mediated fibrinolysis, while negligible changes were observed on tPA-mediated fibrinolysis. The accelerating effect of polyP65 on uPA-mediated fibrinolysis was overcome by additional plasminogen, while the down-regulation of tPA-mediated lysis and plasmin generation was largely unaffected. PolyP65 exerts opposing effects on tPA- and uPA-mediated fibrinolysis, attenuating the fibrin cofactor function in tPA-mediated plasminogen activation. In contrast, polyP may facilitate the interaction between fibrin-independent uPA and plasminogen thereby accelerating plasmin generation and downstream fibrinolysis.
Topics: Fibrinolysin; Fibrinolysis; Humans; Plasminogen; Polyphosphates; Tissue Plasminogen Activator; Urokinase-Type Plasminogen Activator
PubMed: 32029503
DOI: 10.3324/haematol.2019.237966 -
Croatian Medical Journal Dec 2023Soluble fibrin is composed mainly of desA fibrin and fibrinogen oligomers consisting of fewer than 16 monomers partially cross-linked by factor XIIIa. Soluble fibrin... (Review)
Review
Soluble fibrin is composed mainly of desA fibrin and fibrinogen oligomers consisting of fewer than 16 monomers partially cross-linked by factor XIIIa. Soluble fibrin cannot stimulate Glu-plasminogen activation by tissue plasminogen activator (t-PA); therefore, it may not be a direct predecessor of D-dimer. However, within the microcirculatory system, soluble fibrin oligomers may form microclots. Fibrin microclots stimulate Glu-plasminogen activation by t-PA, a process resulting in the formation of Glu-plasmin. Glu-plasmin dissolves the microclots, forming D-dimer. In normal and pathological blood plasma samples, soluble fibrin levels are substantially higher than those of D-dimer. Their concentrations in the plasma are also regulated by transendothelial transfer, absorption by blood macrophages, and binding and internalization with low-density lipoprotein receptors of the cells of the reticuloendothelial system. Therefore, the exact mechanisms of fibrin clots formation and elimination in normal and pathological conditions remain unclear. In this study, we reviewed findings on the molecular mechanisms of the formation and dissolution of fibrin clots, fibrin-dependent activation of Glu-plasminogen by t-PA, and blood plasma behavior in the microcirculatory system. Finally, we proposed a model that explains the relations of D-dimer and soluble fibrin underlying the common and separate mechanisms of their formation and elimination.
Topics: Humans; Tissue Plasminogen Activator; Fibrinolysin; Microcirculation; Plasminogen; Fibrin
PubMed: 38168523
DOI: 10.3325/cmj.2023.64.421 -
The Cochrane Database of Systematic... Oct 2019Pleural infection, including parapneumonic effusions and thoracic empyema, may complicate lower respiratory tract infections. Standard treatment of these collections in... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Pleural infection, including parapneumonic effusions and thoracic empyema, may complicate lower respiratory tract infections. Standard treatment of these collections in adults involves antibiotic therapy, effective drainage of infected fluid and surgical intervention if conservative management fails. Intrapleural fibrinolytic agents such as streptokinase and alteplase have been hypothesised to improve fluid drainage in complicated parapneumonic effusions and empyema and therefore improve treatment outcomes and prevent the need for thoracic surgical intervention. Intrapleural fibrinolytic agents have been used in combination with DNase, but this is beyond the scope of this review.
OBJECTIVES
To assess the benefits and harms of adding intrapleural fibrinolytic therapy to standard conservative therapy (intercostal catheter drainage and antibiotic therapy) in the treatment of complicated parapneumonic effusions and empyema.
SEARCH METHODS
We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE and Embase, ClinicalTrials.gov and the World Health Organization (WHO) trials portal. We contacted trial authors for further information and requested details regarding the possibility of unpublished trials. The most recent search was conducted on 28 August 2019.
SELECTION CRITERIA
Parallel-group randomised controlled trials (RCTs) in adult patients with post-pneumonic empyema or complicated parapneumonic effusions (excluding tuberculous effusions) who had not had prior surgical intervention or trauma comparing an intrapleural fibrinolytic agent (streptokinase, alteplase or urokinase) versus placebo or a comparison of two fibrinolytic agents.
DATA COLLECTION AND ANALYSIS
Two review authors independently extracted data. We contacted study authors for further information. We used odds ratios (OR) for dichotomous data and reported 95% confidence intervals (CIs). We used Cochrane's standard methodological procedures of meta-analysis. We applied the GRADE approach to summarise results and to assess the overall certainty of evidence.
MAIN RESULTS
We included in this review a total of 12 RCTs. Ten studies assessed fibrinolytic agents versus placebo (993 participants); one study compared streptokinase with urokinase (50 participants); and one compared alteplase versus urokinase (99 participants). The primary outcomes were death, requirement for surgical intervention, overall treatment failure and serious adverse effects. All studies were in the inpatient setting. Outcomes were measured at varying time points from hospital discharge to three months. Seven trials were at low or unclear risk of bias and two at high risk of bias due to inadequate randomisation and inappropriate study design respectively. We found no evidence of difference in overall mortality with fibrinolytic versus placebo (OR 1.16, 95% CI 0.71 to 1.91; 8 studies, 867 participants; I² = 0%; moderate certainty of evidence). We found evidence of a reduction in surgical intervention with fibrinolysis in the same studies (OR 0.37, 95% CI 0.21 to 0.68; 8 studies, 897 participants; I² = 51%; low certainty of evidence); and overall treatment failure (OR 0.16, 95% CI 0.05 to 0.58; 7 studies, 769 participants; I² = 88%; very low certainty of evidence, with evidence of significant heterogeneity). We found no clear evidence of an increase in adverse effects with intrapleural fibrinolysis, although this cannot be excluded (OR 1.28, 95% CI 0.36 to 4.57; low certainty of evidence). In a sensitivity analysis, the reduction in referrals for surgery and overall treatment failure with fibrinolysis disappeared when the analysis was confined to studies at low or unclear risk of bias. In a moderate-risk population (baseline 14% risk of death, 20% risk of surgery, 27% risk of treatment failure), intra-pleural fibrinolysis leads to 19 more deaths (36 fewer to 59 more), 115 fewer surgical interventions (150 fewer to 55 fewer) and 214 fewer overall treatment failures (252 fewer to 93 fewer) per 1000 people. A single study of streptokinase versus urokinase found no clear difference between the treatments for requirement for surgery (OR 1.00, 95% CI 0.13 to 7.72; 50 participants; low-certainty evidence). A single study of alteplase versus urokinase showed no clear difference in requirement for surgery (OR alteplase versus urokinase 0.46, 95% CI 0.04 to 5.24) but an increased rate of adverse effects, primarily bleeding, with alteplase (OR 5.61, 95% CI 1.16 to 27.11; 99 participants; low-certainty evidence). This translated into 154 (6 to 499 more) serious adverse events with alteplase compared with urokinase per 1000 people treated.
AUTHORS' CONCLUSIONS
In patients with complicated infective pleural effusion or empyema, intrapleural fibrinolytic therapy was associated with a reduction in the requirement for surgical intervention and overall treatment failure but with no evidence of change in mortality. Discordance between the negative largest trial of this therapy and other studies is of concern, however, as is an absence of significant effect when analysing low risk of bias trials only. The reasons for this difference are uncertain but may include publication bias. Intrapleural fibrinolytics may increase the rate of serious adverse events, but the evidence is insufficient to confirm or exclude this possibility.
Topics: Anti-Bacterial Agents; Drainage; Empyema, Pleural; Fibrinolytic Agents; Humans; Pleural Effusion; Randomized Controlled Trials as Topic; Streptokinase; Thrombolytic Therapy; Tissue Plasminogen Activator; Urokinase-Type Plasminogen Activator
PubMed: 31684683
DOI: 10.1002/14651858.CD002312.pub4 -
Molecular Biology Reports Feb 2023Bikunin is a small chondroitin sulfate proteoglycan (PG) with Ser-protease inhibitory activity that plays pleiotropic roles in health and disease. It is involved in... (Review)
Review
Bikunin is a small chondroitin sulfate proteoglycan (PG) with Ser-protease inhibitory activity that plays pleiotropic roles in health and disease. It is involved in several physiological processes including stabilization of the extracellular matrix (ECM) of connective tissues and key reproductive events. Bikunin is also implicated in both acute and chronic inflammatory conditions and represents a non-invasive circulating and/or urinary (as Urinary Trypsin Inhibitor or UTI) biomarker. It exerts inhibitory effects on urokinase-type plasminogen activator (uPA) and its receptor (uPAR) mediating tumor invasiveness by a down-regulation of uPA mRNA expression, thus representing an anti-metastatic agent. However, only limited data on its potential as a diagnostic and/or prognostic marker of cancer have been reported so far. Recent technological advances in mass spectrometry-based proteomics have provided researchers with a huge amount of information allowing for large-scale surveys of the cancer proteome. To address such issues, we analyzed bikunin expression data across several types of tumors, by using UALCAN proteogenomic analysis portal. In this article we critically review the roles of bikunin in human pathobiology, with a special focus on its inhibitory effects and mechanisms in cancer aggressiveness as well as its significance as cancer circulating biomarker.
Topics: Humans; Glycoproteins; Neoplasm Invasiveness; Extracellular Matrix; Down-Regulation; Biomarkers, Tumor; Urokinase-Type Plasminogen Activator
PubMed: 36414878
DOI: 10.1007/s11033-022-08117-2 -
Biomolecules Jan 2022Pancreatic cancer is a highly aggressive malignancy that features high recurrence rates and the poorest prognosis of all solid cancers. The urokinase plasminogen... (Review)
Review
Pancreatic cancer is a highly aggressive malignancy that features high recurrence rates and the poorest prognosis of all solid cancers. The urokinase plasminogen activation system (uPAS) is strongly implicated in the pathophysiology and clinical outcomes of patients with pancreatic ductal adenocarcinoma (PDAC), which accounts for more than 90% of all pancreatic cancers. Overexpression of the urokinase-type plasminogen activator (uPA) or its cell surface receptor uPAR is a key step in the acquisition of a metastatic phenotype via multiple mechanisms, including the increased activation of cell surface localised plasminogen which generates the serine protease plasmin. This triggers multiple downstream processes that promote tumour cell migration and invasion. Increasing clinical evidence shows that the overexpression of uPA, uPAR, or of both is strongly associated with worse clinicopathological features and poor prognosis in PDAC patients. This review provides an overview of the current understanding of the uPAS in the pathogenesis and progression of pancreatic cancer, with a focus on PDAC, and summarises the substantial body of evidence that supports the role of uPAS components, including plasminogen receptors, in this disease. The review further outlines the clinical utility of uPAS components as prospective diagnostic and prognostic biomarkers for PDAC, as well as a rationale for the development of novel uPAS-targeted therapeutics.
Topics: Carcinoma, Pancreatic Ductal; Humans; Pancreatic Neoplasms; Plasminogen; Prospective Studies; Urokinase-Type Plasminogen Activator
PubMed: 35204653
DOI: 10.3390/biom12020152 -
Seminars in Thrombosis and Hemostasis Apr 2022Tissue plasminogen activator's (tPA) fibrinolytic function in the vasculature is well-established. This specific role for tPA in the vasculature, however, contrasts with... (Review)
Review
Tissue plasminogen activator's (tPA) fibrinolytic function in the vasculature is well-established. This specific role for tPA in the vasculature, however, contrasts with its pleiotropic activities in the central nervous system. Numerous physiological and pathological functions have been attributed to tPA in the central nervous system, including neurite outgrowth and regeneration; synaptic and spine plasticity; neurovascular coupling; neurodegeneration; microglial activation; and blood-brain barrier permeability. In addition, multiple substrates, both plasminogen-dependent and -independent, have been proposed to be responsible for tPA's action(s) in the central nervous system. This review aims to dissect a subset of these different functions and the different molecular mechanisms attributed to tPA in the context of learning and memory. We start from the original research that identified tPA as an immediate-early gene with a putative role in synaptic plasticity to what is currently known about tPA's role in a learning and memory disorder, Alzheimer's disease. We specifically focus on studies demonstrating tPA's involvement in the clearance of amyloid-β and neurovascular coupling. In addition, given that tPA has been shown to regulate blood-brain barrier permeability, which is perturbed in Alzheimer's disease, this review also discusses tPA-mediated vascular dysfunction and possible alternative mechanisms of action for tPA in Alzheimer's disease pathology.
Topics: Alzheimer Disease; Humans; Neuronal Plasticity; Tissue Plasminogen Activator
PubMed: 34942669
DOI: 10.1055/s-0041-1740265 -
Reproductive Sciences (Thousand Oaks,... Mar 2022As a key mechanism in fibrinolysis and tissue remodeling, the plasminogen activator system has been suggested in the process of endometrial shedding and tissue...
As a key mechanism in fibrinolysis and tissue remodeling, the plasminogen activator system has been suggested in the process of endometrial shedding and tissue remodeling. Previous studies have explored the role of estrogen, progesterone, and androgen receptors as well as elements of the renin-angiotensin-aldosterone system in shaping the morphology of the endometrium. This study investigates the distribution and concentrations of the mineralocorticoid receptor, glucocorticoid receptor, tissue plasminogen activator, urokinase plasminogen activator, and plasminogen activator inhibitor-1 within the endometrial stroma, glandular, and endothelial cells of the primate endometrium during artificial menstrual cycles. Our immunohistochemistry quantification shows mineralocorticoid and glucocorticoid receptors are ubiquitously distributed within the macaque endometrium with their patterns of expression following similar fluctuations to urokinase and tissue plasminogen activators particularly within the endometrial vasculature. These proteins are present in endometrial vasculature in high levels during the proliferative phase, decreasing levels during the secretory phase followed by rising levels in the menstrual phase. These similarities could suggest overlapping pathways and interactions between the plasminogen activator system and the steroid receptors within the endometrium. Given the anti-inflammatory properties of glucocorticoids and the role of plasminogen activators in endometrial breakdown, the glucocorticoid receptor may be contributing to stabilizing the endometrium by regulating plasminogen activators during the proliferative phase and menstruation. Furthermore, given the anti-mineralocorticoid properties of certain anti-androgenic progestins and their reduced unscheduled uterine bleeding patterns, the mineralocorticoid receptor may be involved in unscheduled endometrial bleeding.
Topics: Animals; Endometrium; Female; Macaca mulatta; Menstrual Cycle; Receptors, Glucocorticoid; Receptors, Mineralocorticoid; Tissue Plasminogen Activator
PubMed: 34796470
DOI: 10.1007/s43032-021-00797-8 -
The Journal of Biological Chemistry Jan 2024Calreticulin (CRT) was originally identified as a key calcium-binding protein of the endoplasmic reticulum. Subsequently, CRT was shown to possess multiple intracellular...
Calreticulin (CRT) was originally identified as a key calcium-binding protein of the endoplasmic reticulum. Subsequently, CRT was shown to possess multiple intracellular functions, including roles in calcium homeostasis and protein folding. Recently, several extracellular functions have been identified for CRT, including roles in cancer cell invasion and phagocytosis of apoptotic and cancer cells by macrophages. In the current report, we uncover a novel function for extracellular CRT and report that CRT functions as a plasminogen-binding receptor that regulates the conversion of plasminogen to plasmin. We show that human recombinant or bovine tissue-derived CRT dramatically stimulated the conversion of plasminogen to plasmin by tissue plasminogen activator or urokinase-type plasminogen activator. Surface plasmon resonance analysis revealed that CRT-bound plasminogen (K = 1.8 μM) with moderate affinity. Plasminogen binding and activation by CRT were inhibited by ε-aminocaproic acid, suggesting that an internal lysine residue of CRT interacts with plasminogen. We subsequently show that clinically relevant CRT variants (lacking four or eight lysines in carboxyl-terminal region) exhibited decreased plasminogen activation. Furthermore, CRT-deficient fibroblasts generated 90% less plasmin and CRT-depleted MDA MB 231 cells also demonstrated a significant reduction in plasmin generation. Moreover, treatment of fibroblasts with mitoxantrone dramatically stimulated plasmin generation by WT but not CRT-deficient fibroblasts. Our results suggest that CRT is an important cellular plasminogen regulatory protein. Given that CRT can empower cells with plasmin proteolytic activity, this discovery may provide new mechanistic insight into the established role of CRT in cancer.
Topics: Animals; Cattle; Humans; Calreticulin; Fibrinolysin; Plasminogen; Tissue Plasminogen Activator; Urokinase-Type Plasminogen Activator; Protein Domains; Mutation; Recombinant Proteins; Gene Knockout Techniques; Cell Line, Tumor; Neoplasms
PubMed: 37979915
DOI: 10.1016/j.jbc.2023.105465 -
Proceedings of the National Academy of... Jan 2023The urokinase-type plasminogen activator (uPA) system consists of the proteinase uPA, its receptor (PLAUR/uPAR). Under physiological conditions, uPA and PLAUR are...
The urokinase-type plasminogen activator (uPA) system consists of the proteinase uPA, its receptor (PLAUR/uPAR). Under physiological conditions, uPA and PLAUR are predominantly expressed by blood cells, including neutrophils, monocytes, and macrophages, and play important roles in cell activation, adhesion, migration, and extravasation. Here, we report that PLAUR, which is highly expressed in macrophages and dendritic cells (DCs) but hardly expressed in CD4 T cells, inhibits the release of HIV-1 progeny virions from the cell membrane. Silencing markedly enhanced the transmission of HIV-1 in macrophages and DCs. We further demonstrated that PLAUR is localized at the cell membrane to block the release of HIV-1 virions. Interestingly, we found that uPA compromises the PLAUR-mediated inhibition to slightly enhance HIV-1 production in primary macrophages and DCs. In the absence of PLAUR, this enhanced effect induced by uPA is abrogated. In conclusion, PLAUR is a new anti-HIV-1 protein produced in both macrophages and DCs where it inhibits HIV-1 transmission. This discovery may provide a novel therapeutic target for combating HIV.
Topics: Humans; Cell Membrane; HIV-1; Receptors, Urokinase Plasminogen Activator; Urokinase-Type Plasminogen Activator; Virion; Virus Replication
PubMed: 36638209
DOI: 10.1073/pnas.2212991120 -
Frontiers in Molecular Biosciences 2021Thrombosis, a major cause of deaths in this modern era responsible for 31% of all global deaths reported by WHO in 2017, is due to the aggregation of fibrin in blood... (Review)
Review
Thrombosis, a major cause of deaths in this modern era responsible for 31% of all global deaths reported by WHO in 2017, is due to the aggregation of fibrin in blood vessels which leads to myocardial infarction or other cardiovascular diseases (CVDs). Classical agents such as anti-platelet, anti-coagulant drugs or other enzymes used for thrombosis treatment at present could leads to unwanted side effects including bleeding complication, hemorrhage and allergy. Furthermore, their high cost is a burden for patients, especially for those from low and middle-income countries. Hence, there is an urgent need to develop novel and low-cost drugs for thrombosis treatment. Fibrinolytic enzymes, including plasmin like proteins such as proteases, nattokinase, and lumbrokinase, as well as plasminogen activators such as urokinase plasminogen activator, and tissue-type plasminogen activator, could eliminate thrombi with high efficacy rate and do not have significant drawbacks by directly degrading the fibrin. Furthermore, they could be produced with high-yield and in a cost-effective manner from microorganisms as well as other sources. Hence, they have been considered as potential compounds for thrombosis therapy. Herein, we will discuss about natural mechanism of fibrinolysis and thrombus formation, the production of fibrinolytic enzymes from different sources and their application as drugs for thrombosis therapy.
PubMed: 34124160
DOI: 10.3389/fmolb.2021.680397