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González-Miguel J, Siles-Lucas M, Kartashev V, Morchón R, Simón F. Plasmin in Parasitic Chronic Infections: Friend or Foe? Trends Parasitol 2016; 32:325-335. [PMID: 26775037 DOI: 10.1016/j.pt.2015.12.012] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2015] [Revised: 12/04/2015] [Accepted: 12/16/2015] [Indexed: 12/24/2022]
Abstract
Plasmin is the final product of the fibrinolytic system, the physiological mechanism responsible for dissolving fibrin clots. Its broad-range proteolytic activity implies that interaction with fibrinolysis and recruitment of plasmin by blood and tissue parasites is an important mechanism that mediates the invasion and establishment of this kind of pathogen in the hosts. However, recent studies have linked an excess of plasmin generated by this interaction with serious pathological events at the vascular level, including the proliferation and migration of arterial wall cells, inflammation, and degradation of the extracellular matrix. Therefore, we present data that support the need to reconsider the role of plasmin, as well as its benefits or drawbacks, in the context of host-parasite relations.
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Affiliation(s)
- Javier González-Miguel
- Laboratory of Parasitology, Faculty of Pharmacy, University of Salamanca, 37007, Salamanca, Spain.
| | | | - Vladimir Kartashev
- Department of Infectious Diseases, Rostov State Medical University, Rostov-na-Donu, Russia
| | - Rodrigo Morchón
- Laboratory of Parasitology, Faculty of Pharmacy, University of Salamanca, 37007, Salamanca, Spain
| | - Fernando Simón
- Laboratory of Parasitology, Faculty of Pharmacy, University of Salamanca, 37007, Salamanca, Spain
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Fibrinolytic PLGA nanoparticles for slow clot lysis within abdominal aortic aneurysms attenuate proteolytic loss of vascular elastic matrix. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2015; 59:145-156. [PMID: 26652359 DOI: 10.1016/j.msec.2015.09.056] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2015] [Revised: 08/17/2015] [Accepted: 09/13/2015] [Indexed: 01/19/2023]
Abstract
Abdominal aortic aneurysms (AAAs) involve chronic overexpression of proteases in the aortic wall that result in disruption of elastic fibers and consequent loss of vessel elasticity. Nearly 75% of AAAs contain flow-obstructing, fibrin-rich intraluminal thrombi (ILT), which act as a) a bioinert shield, protecting the underlying AAA wall from high hemodynamic stresses, and b) a reservoir of inflammatory cells and proteases that cause matrix breakdown. For these reasons, restoring flow through the aorta lumen and facilitating transmural diffusion of therapeutics from circulation to the AAA wall must be achieved by slow thrombolysis of the ILT to render it porous without rapid breakdown. Intravenously dosed tissue plasminogen activator (tPA) has been shown to rapidly lyse ILTs in acute stroke and myocardial infarctions. For future use in opening up AAA segments, in this study, we investigated the ability of tPA released from poly(lactic-co-glycolic acid) nanoparticles (PLGA NPs) to slowly lyse fibrin clots without inducing proteolytic injury and matrix synthesis-inhibitory effects on cultured rat aneurysmal smooth muscle cells (EaRASMCs). Fibrin clot lysis time was greatly extended over that in presence of exogenous tPA. Surface functionalization of NPs with a cationic amphiphile allowed them to bind to anionic fibrin clot, release tPA at a slower rate and to lyse the clot as a front proceeding outwards in unlike the more rapid and homogenous lysis that occurred due to anionic PLGA NPs. Elastic matrix content was decreased in EaRASMC cultures exposed to byproducts of clot lysis with exogenous tPA, but not tPA-NPs, and was likely due to increased proteolytic activity (MMPs, plasmin) in EaRASMC cultures exposed to exogenous tPA-lysed clots. Our results suggest that gradual ILT lysis via slow release of tPA from NPs will be likely beneficial over exogenous tPA delivery in preserving elastic matrix content and attenuating matrilysis in the adjoining AAA wall, in vivo, while rendering the ILT porous to facilitate transmural delivery of endoluminally delivered AAA therapeutics.
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Jarman ER, Khambata VS, Yun Ye L, Cheung K, Thomas M, Duggan N, Jarai G. A translational preclinical model of interstitial pulmonary fibrosis and pulmonary hypertension: mechanistic pathways driving disease pathophysiology. Physiol Rep 2014; 2:e12133. [PMID: 25214520 PMCID: PMC4270229 DOI: 10.14814/phy2.12133] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2014] [Revised: 08/05/2014] [Accepted: 08/06/2014] [Indexed: 01/11/2023] Open
Abstract
Idiopathic pulmonary fibrosis (IPF) is a chronic progressive interstitial lung disease, in which a decline in patient prognosis is frequently associated with the onset of pulmonary hypertension (PH). Animal models exhibiting principle pathophysiological features of IPF and PH could provide greater insight into mechanistic pathways underlying disease progression and a means for evaluating novel therapeutic approaches for intervention. Here, we describe an in vivo disease model, in which animals develop progressive interstitial pulmonary fibrosis and associated PH, as defined by the presence of fibrotic foci adjacent to areas of alveolar injury and remodeling of the pulmonary vasculature. Associated changes in physiological parameters included a decline in lung function and increase in mean pulmonary arterial pressure (mPAP) >25 mmHg. The early fibrotic pathology is associated with a profibrogenic microenvironment, elevated levels of the matrix metalloproteases, MMP-2, MMP-7, and MMP-12, TIMP-1, the chemoattractant and mitogen, PDGF-β, and the chemokines CCL2 and CXCL12, that are associated with the recruitment of macrophages, mast cells, and fibrocytes. Principle mechanistic pathways associated with disease pathogenesis are upregulated in the lungs and pulmonary arteries, with sustained increases in gene transcripts for the profibrotic mediator TGF-β1 and components of the TGF-β signaling pathway; PAI-1, Nox-4, and HIF-1α. Therapeutic treatment with the ALK-5/TGF-β RI inhibitor SB-525334 reversed established pulmonary fibrosis and associated vascular remodeling, leading to normalization in clinically translatable physiological parameters including lung function and hemodynamic measurements of mPAP. These studies highlight the application of this model in validating potential approaches for targeting common mechanistic pathways driving disease pathogenesis.
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Affiliation(s)
- Elizabeth R. Jarman
- Respiratory Disease Area, Novartis Institutes for BioMedical Research, Horsham, West Sussex, UK
| | - Valerie S. Khambata
- Respiratory Disease Area, Novartis Institutes for BioMedical Research, Horsham, West Sussex, UK
| | - Li Yun Ye
- Respiratory Disease Area, Novartis Institutes for BioMedical Research, Horsham, West Sussex, UK
| | - Kenneth Cheung
- Respiratory Disease Area, Novartis Institutes for BioMedical Research, Horsham, West Sussex, UK
| | - Matthew Thomas
- Respiratory Disease Area, Novartis Institutes for BioMedical Research, Horsham, West Sussex, UK
| | - Nicholas Duggan
- Respiratory Disease Area, Novartis Institutes for BioMedical Research, Horsham, West Sussex, UK
| | - Gabor Jarai
- Respiratory Disease Area, Novartis Institutes for BioMedical Research, Horsham, West Sussex, UK
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Shang RZ, Dai B, Wang DS. Role of uPA/uPAR system in tumors. Shijie Huaren Xiaohua Zazhi 2014; 22:1235-1240. [DOI: 10.11569/wcjd.v22.i9.1235] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Urokinase type plasminogen activator (uPA) is a major activator of plasminogen, and uPA receptor is the specific receptor of uPA. The uPA/uPAR system regulates plasminogen activity, which participates in degradation and remodeling of the extracellular matrix (ECM), and is involved in many pathophysiological processes. In neoplasms, the activation of plasminogen into plasmin caused by the uPA/uPAR system induces the degradation of components in the basement membrane as well as in the ECM, which provides a favorable microenvironment for tumor invasion and metastasis. In addition, the uPA/uPAR system regulates tumor proliferation and angiogenesis. In this review, we will discuss the role of the uPA/uPAR system in tumors and its potential clinical implications.
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Simone TM, Archambeault J, Higgins PJ. Small Molecule Targeting of PAI-1 Function: A New Therapeutic Approach for Treatment of Vascular Stenosis. J Mol Genet Med 2013; 7. [PMID: 24382978 PMCID: PMC3875289 DOI: 10.4172/1747-0862.1000059] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Affiliation(s)
- Tessa M Simone
- Center for Cell Biology & Cancer Research, Albany Medical College, Albany, New York 12208, USA
| | - Jaclyn Archambeault
- Center for Cell Biology & Cancer Research, Albany Medical College, Albany, New York 12208, USA
| | - Paul J Higgins
- Center for Cell Biology & Cancer Research, Albany Medical College, Albany, New York 12208, USA
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DiMusto PD, Lu G, Ghosh A, Roelofs KJ, Su G, Zhao Y, Lau CL, Sadiq O, McEvoy B, Laser A, Diaz JA, Wakefield TW, Henke PK, Eliason JL, Upchurch GR. Increased PAI-1 in females compared with males is protective for abdominal aortic aneurysm formation in a rodent model. Am J Physiol Heart Circ Physiol 2012; 302:H1378-86. [PMID: 22307671 DOI: 10.1152/ajpheart.00620.2011] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The serine proteases, along with their inhibitor plasmin activator inhibitor-1 (PAI-1), have been shown to play a role in abdominal aortic aneurysm (AAA) formation. The aim of this study is to determine if PAI-1 may be a protective factor for AAA formation and partially responsible for the gender difference observed in AAAs. Male and female wild-type (WT) C57BL/6 and PAI-1(-/-) mice 8-12 wk of age underwent aortic perfusion with porcine pancreatic elastase. Animals were harvested 14 days following perfusion and analyzed for phenotype, PAI-1 protein levels, and matrix metalloproteinase (MMP)-9 and -2 activity. WT males had an average increase in aortic diameter of 80%, whereas females only increased 32% (P < 0.001). PAI-1(-/-) males increased 204% and females 161%, significantly more than their WT counterparts (P < 0.001). Western blot revealed 61% higher PAI-1 protein levels in the WT females compared with the WT males (P = 0.01). Zymography revealed higher levels of pro-MMP-2 and active MMP-2 in the PAI-1(-/-) males and females compared with their WT counterparts. PAI-1(-/-) females had significantly higher serum plasmin levels compared with WT females (P = 0.003). In conclusion, WT female mice are protected from aneurysm formation and have higher levels of PAI-1 compared with males during experimental aneurysm formation. Additionally, both male and female PAI-1(-/-) animals develop significantly larger aneurysms than WT animals, correlating with higher pro- and active MMP-2 levels. These findings suggest that PAI-1 is protective for aneurysm formation in the elastase model of AAA and plays a role in the gender differences seen in AAA formation.
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Affiliation(s)
- Paul D DiMusto
- Jobst Vascular Research Laboratory, Department of Surgery, University of Michigan, Ann Arbor, USA
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Bae HB, Zmijewski JW, Deshane JS, Zhi D, Thompson LC, Peterson CB, Chaplin DD, Abraham E. Vitronectin inhibits neutrophil apoptosis through activation of integrin-associated signaling pathways. Am J Respir Cell Mol Biol 2012; 46:790-6. [PMID: 22281987 DOI: 10.1165/rcmb.2011-0187oc] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Vitronectin is present in large concentrations in serum and the extracellular matrix. Although vitronectin is known to modulate neutrophil adhesion and chemotaxis, and to contribute to neutrophil-associated proinflammatory processes, a role in apoptosis has not been demonstrated. In the present studies, we found that neutrophils demonstrated more rapid progression to spontaneous or TNF-related apoptosis-inducing ligand-induced apoptosis when incubated under vitronectin-free conditions than when vitronectin was present. The ability of native vitronectin to delay neutrophil apoptosis was not recapitulated by the vitronectin somatomedin B domain. In contrast, inclusion of the cyclo[Arg-Gly-Asp-D-Phe-Val] peptide in cultures containing vitronectin resulted in enhanced neutrophil apoptosis, showing that the vitronectin RGD motif (Arg-Gly-Asp motif) was responsible for the antiapoptotic effects of vitronectin. Addition of antibodies to β(1), β(3), or β(5), but not to β(2) or β(4) integrins, reversed the ability of vitronectin to diminish neutrophil apoptosis. The ability of vitronectin to enhance neutrophil viability was dependent on activation of phosphatidylinositol 3-kinase and extracellular signal-regulated kinase 1/2 kinases, but not on the p38 kinase. Increased numbers of apoptotic neutrophils were present in the lungs of LPS-treated transgenic vitronectin-deficient mice, as compared with control mice. These results demonstrate a novel antiapoptotic function for vitronectin.
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Affiliation(s)
- Hong-Beom Bae
- Department of Medicine, University of Alabama at Birmingham Division of Pulmonary, Allergy & Critical Care Medicine, 901 19th Street South, Birmingham, AL 35294, USA
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Abstract
Cell activation by stressors is characterized by a sequence of detectable phenotypic cell changes. A given stimulus, depending on its strength, induces modifications in the activity of membrane phospholipid transporters and calpains, which lead to phosphatidylserine exposure, membrane blebbing and the release of microparticles (nanoscale membrane vesicles). This vesiculation could be considered as a warning signal that may be followed, if the stimulus is maintained, by cell detachment-induced apoptosis. In the present study, plasminogen incubated with adherent cells is converted into plasmin by constitutively expressed tPA (tissue-type plasminogen activator) or uPA (urokinase-type plasminogen activator). Plasmin formed on the cell membrane then induces a unique response characterized by membrane blebbing and vesiculation. Hitherto unknown for plasmin, these membrane changes are similar to those induced by thrombin on platelets. If plasmin formation persists, matrix proteins are then degraded, cells lose their attachments and enter the apoptotic process, characterized by DNA fragmentation and specific ultrastructural features. Since other proteolytic or inflammatory stimuli may evoke similar responses in different types of adherent cells, the proposed experimental procedure can be used to distinguish activated adherent cells from cells entering the apoptotic process. Such a distinction is crucial for evaluating the effects of mediators, inhibitors and potential therapeutic agents.
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Schuliga M, Harris T, Stewart AG. Plasminogen activation by airway smooth muscle is regulated by type I collagen. Am J Respir Cell Mol Biol 2010; 44:831-9. [PMID: 20693403 DOI: 10.1165/rcmb.2009-0469oc] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Plasmin, the activated protease product of plasminogen, is involved in collagen remodeling, and is strongly implicated in asthma pathophysiology by recent genome-wide association studies. This study examines plasminogen "activation" by airway smooth muscle cells, and its regulation in a fibrotic environment created by culture on type I collagen and incubation with transforming growth factor (TGF)-β. Urokinase plasminogen activator (uPA) activity was detected in the supernatants of human airway smooth muscle cell cultures maintained in serum-free conditions. Incubation with plasminogen (1.5-50.0 μg/ml, 24 h) increased plasmin activity in a concentration-dependent manner (P < 0.001). uPA activity was higher in cultures maintained on fibrillar type I collagen substrata than in those on plastic, as was plasmin activity after incubation with plasminogen (20 μg/ml). Pretreatment with TGF-β (100 pM) for 18 hours inhibited plasminogen activation by airway smooth muscle cells maintained on plastic, but not on collagen. TGF-β stimulated an increase in the level of uPA mRNA in airway smooth muscle cells grown on collagen, but not on plastic. Reducing the levels of β1-integrin collagen receptor, using interference RNA, attenuated plasmin formation by airway smooth muscle cells grown on collagen, and restored the inhibitory effect of TGF-β. This study shows that airway smooth muscle activation of plasminogen by uPA is accelerated in a collagen-rich environment in which the inhibitory effect of TGF-β is attenuated in association with greater uPA expression induced via β1-integrin signaling. These findings suggest that the plasminogen-activation system involving uPA has the potential to contribute to airway wall remodeling in asthma.
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Affiliation(s)
- Michael Schuliga
- Department of Pharmacology, University of Melbourne, Parkville, Victoria, Australia.
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Largo R, Martínez-Calatrava MJ, Sánchez-Pernaute O, Marcos ME, Moreno-Rubio J, Aparicio C, Egido J, Herrero-Beaumont G. Effect of a high dose of glucosamine on systemic and tissue inflammation in an experimental model of atherosclerosis aggravated by chronic arthritis. Am J Physiol Heart Circ Physiol 2009; 297:H268-76. [DOI: 10.1152/ajpheart.00142.2009] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Glucosamine sulfate (GS) is a glycosaminoglycan with anti-inflammatory and immunoregulatory properties. Here we set out to explore the effect of GS administration on markers of systemic and local inflammation in rabbits with atherosclerosis aggravated by chronic arthritis. Atherosclerosis was induced in rabbits by maintaining them on a hyperlipidemic diet after producing an endothelial lesion in the femoral arteries. Simultaneously, chronic arthritis was induced in these animals by repeated intra-articular injections of ovalbumin in previously immunized rabbits. A group of these rabbits was treated prophylactically with oral GS (500 mg·kg−1·day−1), and, when the animals were killed, serum was extracted and peripheral blood mononuclear cells (PBMC) were isolated. Furthermore, the femoral arteries, thoracic aorta, and synovial membranes were examined in gene expression studies and histologically. GS administration reduced circulating levels of the C-reactive protein and of interleukin-6. GS also lowered nuclear factor-κB activation in PBMC, and it downregulated the expression of both the CCL2 (monocyte chemoattractant protein) and cyclooxygenase-2 genes in these cells. Lesions at the femoral wall were milder after GS treatment, as reflected by the intimal-to-media thickened ratio and the absence of aortic lesions. Indeed, GS also attenuated the histological lesions in synovial tissue. In a combined rabbit model of chronic arthritis and atherosclerosis, orally administered GS reduced the markers of inflammation in peripheral blood, as well as the femoral and synovial membrane lesions. GS also prevented the development of inflammation-associated aortic lesions. These results suggest an atheroprotective effect of GS.
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Balsara RD, Ploplis VA. Plasminogen activator inhibitor-1: the double-edged sword in apoptosis. Thromb Haemost 2008; 100:1029-1036. [PMID: 19132226 PMCID: PMC3674867] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Plasminogen activator inhibitor type-1 (PAI-1) is a multi-functional protein. It is a fast-acting inhibitor of plasminogen activators; urokinase-plasminogen activator and tissue type plasminogen activator, and also plays an important role in regulating cell proliferation, adhesion, migration, and signal transduction pathways. These biological events are important processes during angiogenesis and restenosis. PAI-1 has been shown to regulate proliferation, migration, and apoptosis of vascular smooth muscle cells and endothelial cells. The ability of PAI-1 to regulate cellular proliferation and migration has been attributed to its ability to control plasmin production, modify signaling pathways, and its inherent multifactorial ability to bind to vitronectin and lipoprotein receptor-related protein. However, the mechanism by which PAI-1 regulates the apoptotic pathway is not well understood. Evidence from the literature suggests that PAI-1 or its deficiency alters key signalling pathways, such as the PI3-k/Akt and the Jak/STAT pathways, and is involved in maintaining endothelial cell integrity thereby regulating cell death. Other investigators have demonstrated that PAI-1 directly binds to caspases as a mechanism of PAI-1-mediated cellular apoptosis. Moreover, results from studies assessing the role of PAI-1 in apoptosis have suggested that PAI-1 can exert pathogenic or protective effects, which may be related to the disease model or type of injury employed.
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Samarakoon R, Higgins PJ. Integration of non-SMAD and SMAD signaling in TGF-beta1-induced plasminogen activator inhibitor type-1 gene expression in vascular smooth muscle cells. Thromb Haemost 2008; 100:976-83. [PMID: 19132220 PMCID: PMC2963177] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Overexpression of plasminogen activator inhibitor-1 (SERPINE1, PAI-1), the major physiological inhibitor of pericellular plasmin generation, is a significant causative factor in the progression of vascular disorders (e.g. arteriosclerosis, thrombosis, perivascular fibrosis) as well as a biomarker and a predictor of cardiovascular-disease associated mortality. PAI-1 is a temporal/spatial regulator of pericellular proteolysis and ECM accumulation impacting, thereby, vascular remodeling, smooth muscle cell migration, proliferation and apoptosis. Within the specific context of TGF-beta1-initiated vascular fibrosis and neointima formation, PAI-1 is a member of the most prominently expressed subset of TGF-beta1-induced transcripts. Recent findings implicate EGFR/pp60c-src-->MEK/ERK1/2 and Rho/ROCK-->SMAD2/3 signaling in TGF-beta1-stimulated PAI-1 expression in vascular smooth muscle cells. The EGFR is a direct upstream regulator of MEK/ERK1/2 while Rho/ROCK modulate both the duration of SMAD2/3 phosphorylation and nuclear accumulation. E-box motifs (CACGTG) in the PE1/PE2 promoter regions of the human PAI-1 gene, moreover, are platforms for a MAP kinase-directed USF subtype switch (USF-1-->USF-2) in response to growth factor addition suggesting that the EGFR-->MEK/ERK axis impacts PAI-1 expression, at least partly, through USF-dependent transcriptional controls. This paper reviews recent data suggesting the essential cooperativity among the EGFR-->MAP kinase cascade, the Rho/ROCK pathway and SMADs in TGF-beta1-initiated PAI-1 expression. The continued clarification of mechanistic controls on PAI-1 transcription may lead to new targeted therapies and clinically-relevant options for the treatment of vascular diseases in which PAI-1 dysregulation is a major underlying pathogenic feature.
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Affiliation(s)
- Rohan Samarakoon
- Center for Cell Biology & Cancer Research, Albany Medical College, 47 New Scotland Avenue, Albany, New York 12208, USA
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Horowitz JC, Rogers DS, Simon RH, Sisson TH, Thannickal VJ. Plasminogen activation induced pericellular fibronectin proteolysis promotes fibroblast apoptosis. Am J Respir Cell Mol Biol 2007; 38:78-87. [PMID: 17656680 PMCID: PMC2176129 DOI: 10.1165/rcmb.2007-0174oc] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Apoptosis of fibroblasts/myofibroblasts is a critical event in the resolution of tissue repair responses; however, mechanisms for the regulation of (myo)fibroblast apoptosis/survival remain unclear. In this study, we demonstrate counter-regulatory interactions between the plasminogen activation system and transforming growth factor-beta1 (TGF-beta1) in the control of fibroblast apoptosis. Plasmin treatment induced fibroblast apoptosis in a time- and dose-dependent manner in association with proteolytic degradation of extracellular matrix proteins, as detected by the release of soluble fibronectin peptides. Plasminogen, which was activated to plasmin by fibroblasts, also induced fibronectin proteolysis and fibroblast apoptosis, both of which were blocked by alpha2-antiplasmin but not by inhibition of matrix metalloproteinase activity. TGF-beta1 protected fibroblasts from apoptosis induced by plasminogen but not from apoptosis induced by exogenous plasmin. The protection from plasminogen-induced apoptosis conferred by TGF-beta1 is associated with the up-regulation of plasminogen activator-1 (PAI-1) expression and inhibition of plasminogen activation. Moreover, lung fibroblasts from mice genetically deficient in PAI-1 lose the protective effect of TGF-beta1 against plasminogen-induced apoptosis. These findings support a novel role for the plasminogen activation system in the regulation of fibroblast apoptosis and a potential role of TGF-beta1/PAI-1 in promoting (myo)fibroblast survival in chronic fibrotic disorders.
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Affiliation(s)
- Jeffrey C Horowitz
- University of Michigan Medical Center, 6301 MSRB III, 1150 W. Medical Center Dr., Ann Arbor, MI 48109-5642, USA.
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Zou Y, Qi Y, Roztocil E, Nicholl SM, Davies MG. Patterns of kinase activation induced by injury in the murine femoral artery. J Surg Res 2007; 142:332-40. [PMID: 17631902 PMCID: PMC2048817 DOI: 10.1016/j.jss.2007.05.033] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2007] [Revised: 05/07/2007] [Accepted: 05/25/2007] [Indexed: 11/27/2022]
Abstract
BACKGROUND Intimal hyperplasia remains the principal lesion in the development of restenosis after vessel wall injury. Cell signaling in vascular smooth muscle cells remains a potential molecular target to modulate the development of intimal hyperplasia. The aim of this study was to define a baseline pattern of histological changes and kinase activation in a murine model. METHODS The murine femoral wire injury model was used in which a microwire was passed through a branch of the femoral artery and used to denude the common femoral artery. Pluronic gel was used to apply mitogen-activated protein kinases (MAPK) inhibitors (PD98059, SB230580, and SP600125) on the exterior of the vessels. Specimens were perfusion-fixed and sections were stained for morphometry using an ImagePro system. Additional specimens of femoral artery were also harvested and snap frozen for Western blotting and zymography to allow for the study of kinase and protease activation. Contralateral vessels were used as controls. RESULTS The injured femoral arteries developed intimal hyperplasia, which is maximal at 28 days and does not change substantially between day 28 and day 56. Sham-operated vessels did not produce such a response. Cell apoptosis peaked within 3 days and cell proliferation peaked at 7 days after injury. There is a time-dependent increase in kinase activity immediately after injury. MEK1/2 activation peaks at 20 min after injury and is followed by a peak in extracellular signal-regulated kinase-1/2 activation at 45 min. The stress kinases p38(MAPK) and JNK peak between 10 and 20 min. Activation of akt is later at 45 min and 120 min and activation of p70S6K was biphasic. There was a time-dependent increase in uPA/PAI-1 expression and activity after injury. Local application of MAPK inhibitors (PD98059, SB230580, and SP600125) within a pluronic gel reduced respective MAPK activity, decreased cell proliferation and enhanced cell apoptosis, increased PAI-1, and decreased uPA expression and activity; at 14 days there was a decrease in intimal hyperplasia. CONCLUSIONS These data demonstrate that femoral wire injury in the mouse induces a consistent model of intimal hyperplasia and that it is associated with a time dependent increase in signaling kinase activity. Interruption of these pathways will interrupt the uPA/PAI-1 pathway and decrease intimal hyperplasia development. Accurate characterization of cell signaling is a necessary step in the development of molecular therapeutics.
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Affiliation(s)
- Yiping Zou
- Vascular Biology and Therapeutics Program, Department of Surgery, University of Rochester, Rochester, New York, USA
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Zaman AKMT, Fujii S, Schneider DJ, Taatjes DJ, Lijnen HR, Sobel BE. Deleterious effects of lack of cardiac PAI-1 after coronary occlusion in mice and their pathophysiologic determinants. Histochem Cell Biol 2007; 128:135-45. [PMID: 17576591 DOI: 10.1007/s00418-007-0300-z] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/22/2007] [Indexed: 11/25/2022]
Abstract
We sought to delineate mechanisms through which the lack of plasminogen activator inhibitor (PAI)-1 in the heart affects remodeling of the heart early after myocardial infarction (MI). MI was induced by coronary occlusion in 10-weeks old PAI-1 knockout (KO) and control mice. Three days after MI, systolic and diastolic function was assessed with high-resolution echocardiography, infarct size was determined biochemically and histologically and accumulation of acute inflammatory cells in zones of infarction was characterized by immunocytochemistry. PAI-1 KO mice exhibited markedly thickened diastolic left ventricular anterior walls (1.38 +/- 0.38 mm vs. 0.77 +/- 0.13 SD), more profound depression of global and regional cardiac function (19 vs. 22% fractional shortening), and greater evidence of diastolic dysfunction (average E wave amplitude = 568 vs. 675 mm/s) all of which were significant. Markedly greater extent of infarction was demonstrated biochemically and histologically in knockout mice compared with controls (76 vs. 29% of the left ventricle, P < 0.05) associated with striking hemorrhage and intense inflammation. Fibrosis normalized for infarct size was markedly reduced (0.006 vs. 0.022 microg hydroxyproline/mg dry weight). Thus, lack of PAI-1 in the heart exerted deleterious effects mediated, at least in part by increased inflammation and hemorrhage and attenuating of fibrosis.
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Affiliation(s)
- A K M Tarikuz Zaman
- Cardiovascular Research Institute, University of Vermont, Colchester Research Facility, 208 South Park Drive, Colchester, VT 05446, USA
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