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A key role for the urokinase plasminogen activator (uPA) in invasive Group A streptococcal infection.

ABSTRACT: Recruitment of the serine protease plasmin is central to the pathogenesis of many bacterial species, including Group A streptococcus (GAS), a leading cause of morbidity and mortality globally. A key process in invasive GAS disease is the ability to accumulate plasmin at the cell surface, however the role of host activators of plasminogen in this process is poorly understood. Here, we demonstrate for the first time that the urokinase-type plasminogen activator (uPA) contributes to plasmin recruitment and subsequent invasive disease initiation in vivo. In the absence of a source of host plasminogen activators, streptokinase (Ska) was required to facilitate cell surface plasmin acquisition by GAS. However, in the absence of Ska, host activators were sufficient to promote cell surface plasmin acquisition by GAS strain 5448 during incubation with plasminogen or human plasma. Furthermore, GAS were able mediate a significant increase in the activation of zymogen pro-uPA in human plasma. In order to assess the contribution of uPA to invasive GAS disease, a previously undescribed transgenic mouse model of infection was employed. Both C57/black 6J, and AlbPLG1 mice expressing the human plasminogen transgene, were significantly more susceptible to invasive GAS disease than uPA-/- mice. The observed decrease in virulence in uPA-/-mice was found to correlate directly with a decrease in bacterial dissemination and reduced cell surface plasmin accumulation by GAS. These findings have significant implications for our understanding of GAS pathogenesis, and research aimed at therapeutic targeting of plasminogen activation in invasive bacterial infections.

SUBMITTER: Sanderson-Smith ML

PROVIDER: S-EPMC3701706 | biostudies-literature | 2013

REPOSITORIES: biostudies-literature

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A key role for the urokinase plasminogen activator (uPA) in invasive Group A streptococcal infection.

Sanderson-Smith Martina L ML Zhang Yueling Y Ly Diane D Donahue Deborah D Hollands Andrew A Nizet Victor V Ranson Marie M Ploplis Victoria A VA Walker Mark J MJ Castellino Francis J FJ

PLoS pathogens 20130704 7

Recruitment of the serine protease plasmin is central to the pathogenesis of many bacterial species, including Group A streptococcus (GAS), a leading cause of morbidity and mortality globally. A key process in invasive GAS disease is the ability to accumulate plasmin at the cell surface, however the role of host activators of plasminogen in this process is poorly understood. Here, we demonstrate for the first time that the urokinase-type plasminogen activator (uPA) contributes to plasmin recruit ...[more]

PMID: 23853591

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Project description:Data from clinical studies, cell culture, and animal models implicate the urokinase (uPA)/Plasminogen (Plg) system in the development of atherosclerosis and aneurysms. However, the mechanisms through which uPA/Plg stimulate these diseases are not yet defined. We used genetically modified, atherosclerosis-prone mice, including mice with macrophage-specific uPA overexpression to clarify mechanisms of uPA/Plg-accelerated atherosclerosis and aneurysm formation. Microarray studies were performed to identify potential mediators of uPA-accelerated atherosclerosis. These studies identified S100A8 and S100A9 mRNA as the most highly upregulated transcripts in uPA-overexpressing macrophages; upregulation of S100A9 protein in uPA-overexpressing macrophages was confirmed by Western blotting. S100A8/A9, which are atherogenic in mice and are expressed in human atherosclerotic plaques, are also upregulated in aortae of mice with uPA-overexpressing macrophages, and macrophage S100A9 mRNA is upregulated by exposure of wild-type macrophages to medium from uPA-overexpressing macrophages. Bioinformatics analysis of the microarray data suggest significant effects of uPA overexpression on cell migration and cell-matrix interactions. Our results confirm—in a second animal model—that macrophage-expressed uPA stimulates atherosclerosis and aortic dilation. They also implicate specific pathways in uPA/Plg-accelerated atherosclerosis and aneurysmal disease. Six independent biological replicate RNA samples were prepared from thioglycollate-elicited peritoneal macrophages from mice of two different genotypes: SR-uPA+/0 transgenic (overexpress uPA in macrophages) and nontransgenic, respectively), for a total of 12 independent RNA samples. Both transgenic and nontransgenic mice were Apoe-/- and were fed Western diet from 5-15 weeks before peritoneal macrophages were elicited. In addition, from the six samples of each genotype, a pooled sample was prepared by combining the six genotype-specific samples. Each of the two pooled samples was assayed on the BeadChip in two technical replicates, for a total of 16 hybridizations performed using two Illumina Mouse Ref-8 v1.1 chips.

Project description:Data from clinical studies, cell culture, and animal models implicate the urokinase plasminogen activator (uPA)/uPA receptor (uPAR)/plasminogen system in the development of atherosclerosis and aneurysms. However, the mechanisms through which uPA/uPAR/plasminogen stimulate these diseases are not yet defined. We used genetically modified, atherosclerosis-prone mice, including mice with macrophage-specific uPA overexpression and mice genetically deficient in uPAR to elucidate mechanisms of uPA/uPAR/plasminogen-accelerated atherosclerosis and aneurysm formation. We found that macrophage-specific uPA overexpression accelerates atherosclerosis and causes aortic root dilation in fat-fed Ldlr(-/-) mice (as we previously reported in Apoe(-/-) mice). Macrophage-expressed uPA accelerates atherosclerosis by stimulation of lesion progression rather than initiation and causes disproportionate lipid accumulation in early lesions. uPA-accelerated atherosclerosis and aortic dilation are largely, if not completely, independent of uPAR. In the absence of uPA overexpression, however, uPAR contributes modestly to both atherosclerosis and aortic dilation. Microarray studies identified S100A8 and S100A9 mRNA as the most highly up-regulated transcripts in uPA-overexpressing macrophages; up-regulation of S100A9 protein in uPA-overexpressing macrophages was confirmed by Western blotting. S100A8/A9, which are atherogenic in mice and are expressed in human atherosclerotic plaques, are also up-regulated in the aortae of mice with uPA-overexpressing macrophages, and macrophage S100A9 mRNA is up-regulated by exposure of wild-type macrophages to medium from uPA-overexpressing macrophages. Macrophage microarray data suggest significant effects of uPA overexpression on cell migration and cell-matrix interactions. Our results confirm in a second animal model that macrophage-expressed uPA stimulates atherosclerosis and aortic dilation. They also reveal uPAR independence of these actions and implicate specific pathways in uPA/Plg-accelerated atherosclerosis and aneurysmal disease.

Project description:BackgroundPrevious studies have revealed the role of dysregulated urokinase plasminogen activator (encoded by PLAU) expression and activity in several pathways associated with cancer progression. However, systematic investigation into the association of PLAU expression with factors that modulate PDAC (pancreatic ductal adenocarcinoma) progression is lacking, such as those affecting stromal (pancreatic stellate cell, PSC)-cancer cell interactions, tumour immunity, PDAC subtypes and clinical outcomes from potential PLAU inhibition.MethodsThis study used an integrated bioinformatics approach to identify prognostic markers correlated with PLAU expression using different transcriptomics, proteomics, and clinical data sets. We then determined the association of dysregulated PLAU and correlated signatures with oncogenic pathways, metastatic phenotypes, stroma, immunosuppressive tumour microenvironment (TME) and clinical outcome. Finally, using an in vivo orthotopic model of pancreatic cancer, we confirmed the predicted effect of inhibiting PLAU on tumour growth and metastasis.ResultsOur analyses revealed that PLAU upregulation is not only associated with numerous other prognostic markers but also associated with the activation of various oncogenic signalling pathways, aggressive phenotypes relevant to PDAC growth and metastasis, such as proliferation, epithelial-mesenchymal transition (EMT), stemness, hypoxia, extracellular cell matrix (ECM) degradation, upregulation of stromal signatures, and immune suppression in the tumour microenvironment (TME). Moreover, the upregulation of PLAU was directly connected with signalling pathways known to mediate PSC-cancer cell interactions. Furthermore, PLAU upregulation was associated with the aggressive basal/squamous phenotype of PDAC and significantly reduced overall survival, indicating that this subset of patients may benefit from therapeutic interventions to inhibit PLAU activity. Our studies with a clinically relevant orthotopic pancreatic model showed that even short-term PLAU inhibition is sufficient to significantly halt tumour growth and, importantly, eliminate visible metastasis.ConclusionElevated PLAU correlates with increased aggressive phenotypes, stromal score, and immune suppression in PDAC. PLAU upregulation is also closely associated with the basal subtype type of PDAC; patients with this subtype are at high risk of mortality from the disease and may benefit from therapeutic targeting of PLAU.

Dataset Information

A key role for the urokinase plasminogen activator (uPA) in invasive Group A streptococcal infection.

Publications

A key role for the urokinase plasminogen activator (uPA) in invasive Group A streptococcal infection.

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