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Inhibition of SERPINE1 Function Attenuates Wound Closure in Response to Tissue Injury: A Role for PAI-1 in Re-Epithelialization and Granulation Tissue Formation. J Dev Biol 2015. [DOI: 10.3390/jdb3010011] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
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52
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Liu F, Lagares D, Choi KM, Stopfer L, Marinković A, Vrbanac V, Probst CK, Hiemer SE, Sisson TH, Horowitz JC, Rosas IO, Fredenburgh LE, Feghali-Bostwick C, Varelas X, Tager AM, Tschumperlin DJ. Mechanosignaling through YAP and TAZ drives fibroblast activation and fibrosis. Am J Physiol Lung Cell Mol Physiol 2014; 308:L344-57. [PMID: 25502501 DOI: 10.1152/ajplung.00300.2014] [Citation(s) in RCA: 538] [Impact Index Per Article: 53.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Pathological fibrosis is driven by a feedback loop in which the fibrotic extracellular matrix is both a cause and consequence of fibroblast activation. However, the molecular mechanisms underlying this process remain poorly understood. Here we identify yes-associated protein (YAP) (homolog of drosophila Yki) and transcriptional coactivator with PDZ-binding motif (TAZ) (also known as Wwtr1), transcriptional effectors of the Hippo pathway, as key matrix stiffness-regulated coordinators of fibroblast activation and matrix synthesis. YAP and TAZ are prominently expressed in fibrotic but not healthy lung tissue, with particularly pronounced nuclear expression of TAZ in spindle-shaped fibroblastic cells. In culture, both YAP and TAZ accumulate in the nuclei of fibroblasts grown on pathologically stiff matrices but not physiologically compliant matrices. Knockdown of YAP and TAZ together in vitro attenuates key fibroblast functions, including matrix synthesis, contraction, and proliferation, and does so exclusively on pathologically stiff matrices. Profibrotic effects of YAP and TAZ operate, in part, through their transcriptional target plasminogen activator inhibitor-1, which is regulated by matrix stiffness independent of transforming growth factor-β signaling. Immortalized fibroblasts conditionally expressing active YAP or TAZ mutant proteins overcome soft matrix limitations on growth and promote fibrosis when adoptively transferred to the murine lung, demonstrating the ability of fibroblast YAP/TAZ activation to drive a profibrotic response in vivo. Together, these results identify YAP and TAZ as mechanoactivated coordinators of the matrix-driven feedback loop that amplifies and sustains fibrosis.
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Affiliation(s)
- Fei Liu
- Molecular and Integrative Physiological Sciences, Department of Environmental Health, Harvard School of Public Health, Boston, Massachusetts
| | - David Lagares
- Pulmonary and Critical Care Unit and Center for Immunology and Inflammatory Diseases, Massachusetts General Hospital, Charlestown, Massachusetts
| | - Kyoung Moo Choi
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota
| | - Lauren Stopfer
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota
| | - Aleksandar Marinković
- Molecular and Integrative Physiological Sciences, Department of Environmental Health, Harvard School of Public Health, Boston, Massachusetts
| | - Vladimir Vrbanac
- Pulmonary and Critical Care Unit and Center for Immunology and Inflammatory Diseases, Massachusetts General Hospital, Charlestown, Massachusetts
| | - Clemens K Probst
- Pulmonary and Critical Care Unit and Center for Immunology and Inflammatory Diseases, Massachusetts General Hospital, Charlestown, Massachusetts
| | - Samantha E Hiemer
- Department of Biochemistry, Boston University School of Medicine, Boston, Massachusetts
| | - Thomas H Sisson
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, University of Michigan Medical Center, Ann Arbor, Michigan
| | - Jeffrey C Horowitz
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, University of Michigan Medical Center, Ann Arbor, Michigan
| | - Ivan O Rosas
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Brigham and Women's Hospital, Boston, Massachusetts
| | - Laura E Fredenburgh
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Brigham and Women's Hospital, Boston, Massachusetts
| | - Carol Feghali-Bostwick
- Division of Rheumatology and Immunology, Department of Medicine, Medical University of South Carolina, Charleston, South Carolina
| | - Xaralabos Varelas
- Department of Biochemistry, Boston University School of Medicine, Boston, Massachusetts
| | - Andrew M Tager
- Pulmonary and Critical Care Unit and Center for Immunology and Inflammatory Diseases, Massachusetts General Hospital, Charlestown, Massachusetts
| | - Daniel J Tschumperlin
- Molecular and Integrative Physiological Sciences, Department of Environmental Health, Harvard School of Public Health, Boston, Massachusetts; Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota;
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Huang WT, Akhter H, Jiang C, MacEwen M, Ding Q, Antony V, Thannickal VJ, Liu RM. Plasminogen activator inhibitor 1, fibroblast apoptosis resistance, and aging-related susceptibility to lung fibrosis. Exp Gerontol 2014; 61:62-75. [PMID: 25451236 DOI: 10.1016/j.exger.2014.11.018] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2014] [Revised: 11/24/2014] [Accepted: 11/27/2014] [Indexed: 12/31/2022]
Abstract
Idiopathic pulmonary fibrosis (IPF) is a fatal lung disorder with unknown cause and no effective treatment. The incidence of and mortality from IPF increase with age, suggesting that advanced age is a major risk factor for IPF. The mechanism underlying the increased susceptibility of the elderly to IPF, however, is unknown. In this study, we show for the first time that the protein level of plasminogen activator inhibitor 1 (PAI-1), a protease inhibitor which plays an essential role in the control of fibrinolysis, was significantly increased with age in mouse lung homogenate and lung fibroblasts. Upon bleomycin challenge, old mice experienced augmented PAI-1 induction and lung fibrosis as compared to young mice. Most interestingly, we show that fewer (myo)fibroblasts underwent apoptosis and more (myo)fibroblasts with increased level of PAI-1 accumulated in the lung of old than in young mice after bleomycin challenge. In vitro studies further demonstrate that fibroblasts isolated from lungs of old mice were resistant to H2O2 and tumor necrosis factor alpha-induced apoptosis and had augmented fibrotic responses to TGF-β1, compared to fibroblasts isolated from young mice. Inhibition of PAI-1 activity with a PAI-1 inhibitor, on the other hand, eliminated the aging-related apoptosis resistance and TGF-β1 sensitivity in isolated fibroblasts. Moreover, we show that knocking down PAI-1 in human lung fibroblasts with PAI-1 siRNA significantly increased their sensitivity to apoptosis and inhibited their responses to TGF-β1. Together, the results suggest that increased PAI-1 expression may underlie the aging-related sensitivity to lung fibrosis in part by protecting fibroblasts from apoptosis.
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Affiliation(s)
- Wen-Tan Huang
- Department of Environmental Health Sciences, School of Public Health, University of Alabama at Birmingham, Birmingham, USA
| | - Hasina Akhter
- Department of Environmental Health Sciences, School of Public Health, University of Alabama at Birmingham, Birmingham, USA
| | - Chunsun Jiang
- Division of Pulmonary, Allergy, and Critical Care Medicine, University of Alabama at Birmingham, Birmingham, USA
| | - Mark MacEwen
- Department of Pediatrics, University of Alabama at Birmingham, Birmingham, USA
| | - Qiang Ding
- Division of Pulmonary, Allergy, and Critical Care Medicine, University of Alabama at Birmingham, Birmingham, USA
| | - Veena Antony
- Division of Pulmonary, Allergy, and Critical Care Medicine, University of Alabama at Birmingham, Birmingham, USA
| | - Victor John Thannickal
- Division of Pulmonary, Allergy, and Critical Care Medicine, University of Alabama at Birmingham, Birmingham, USA
| | - Rui-Ming Liu
- Department of Environmental Health Sciences, School of Public Health, University of Alabama at Birmingham, Birmingham, USA; Division of Pulmonary, Allergy, and Critical Care Medicine, University of Alabama at Birmingham, Birmingham, USA.
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Role of the urokinase-fibrinolytic system in epithelial-mesenchymal transition during lung injury. THE AMERICAN JOURNAL OF PATHOLOGY 2014; 185:55-68. [PMID: 25447049 DOI: 10.1016/j.ajpath.2014.08.027] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2014] [Revised: 08/04/2014] [Accepted: 08/28/2014] [Indexed: 01/10/2023]
Abstract
Alveolar type II epithelial (ATII) cell injury precedes development of pulmonary fibrosis. Mice lacking urokinase-type plasminogen activator (uPA) are highly susceptible, whereas those deficient in plasminogen activator inhibitor (PAI-1) are resistant to lung injury and pulmonary fibrosis. Epithelial-mesenchymal transition (EMT) has been considered, at least in part, as a source of myofibroblast formation during fibrogenesis. However, the contribution of altered expression of major components of the uPA system on ATII cell EMT during lung injury is not well understood. To investigate whether changes in uPA and PAI-1 by ATII cells contribute to EMT, ATII cells from patients with idiopathic pulmonary fibrosis and chronic obstructive pulmonary disease, and mice with bleomycin-, transforming growth factor β-, or passive cigarette smoke-induced lung injury were analyzed for uPA, PAI-1, and EMT markers. We found reduced expression of E-cadherin and zona occludens-1, whereas collagen-I and α-smooth muscle actin were increased in ATII cells isolated from injured lungs. These changes were associated with a parallel increase in PAI-1 and reduced uPA expression. Further, inhibition of Src kinase activity using caveolin-1 scaffolding domain peptide suppressed bleomycin-, transforming growth factor β-, or passive cigarette smoke-induced EMT and restored uPA expression while suppressing PAI-1. These studies show that induction of PAI-1 and inhibition of uPA during fibrosing lung injury lead to EMT in ATII cells.
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Abstract
Transforming growth factor β (TGF-β) has long been implicated in fibrotic diseases, including the multisystem fibrotic disease systemic sclerosis (SSc). Expression of TGF-β-regulated genes in fibrotic skin and lungs of patients with SSc correlates with disease activity, which points to this cytokine as the central mediator of pathogenesis. Patients with SSc often develop pulmonary arterial hypertension (PAH), a particularly lethal complication caused by vascular dysfunction. Several genetic diseases with vascular features related to SSc, such as familial PAH and hereditary haemorrhagic telangiectasia, are caused by mutations in the TGF-β-sensing ALK-1 signalling pathway. These observations suggest that increased TGF-β signalling causes both vascular and fibrotic features of SSc. The question of how latent TGF-β becomes activated in local SSc tissues is, therefore, central to the understanding of SSc. Both TGF-β1 and TGF-β3 can be activated by integrins αvβ6 and αvβ8, whose upregulation in bronchial epithelial cells can activate TGF-β in SSc lungs. Other αv integrins, thrombospondin-1 or altered TGF-β sequestration by matrix proteins might be important in other target tissues. How the immune system triggers this process remains unclear, although links between inflammation and TGF-β activation are emerging. Together, these observations provide an increasingly secure framework for understanding TGF-β in SSc pathogenesis.
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Affiliation(s)
- Robert Lafyatis
- Boston University School of Medicine, E5 Arthritis Centre, 72 E. Concord Street, Boston, MA 02118, USA
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56
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Jarman ER, Khambata VS, Cope C, Jones P, Roger J, Ye LY, Duggan N, Head D, Pearce A, Press NJ, Bellenie B, Sohal B, Jarai G. An inhibitor of NADPH oxidase-4 attenuates established pulmonary fibrosis in a rodent disease model. Am J Respir Cell Mol Biol 2014; 50:158-69. [PMID: 23977848 DOI: 10.1165/rcmb.2013-0174oc] [Citation(s) in RCA: 75] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Idiopathic pulmonary fibrosis is a chronic progressive disease of increasing prevalence for which there is no effective therapy. Increased oxidative stress associated with an oxidant-antioxidant imbalance is thought to contribute to disease progression. NADPH oxidases (Nox) are a primary source of reactive oxygen species within the lung and cardiovascular system. We demonstrate that the Nox4 isoform is up-regulated in the lungs of patients with IPF and in a rodent model of bleomycin-induced pulmonary fibrosis and vascular remodeling. Nox4 is constitutively active, and therefore increased expression levels are likely to contribute to disease pathology. Using a small molecule Nox4/Nox1 inhibitor, we demonstrate that targeting Nox4 results in attenuation of an established fibrotic response, with reductions in gene transcripts for the extracellular matrix components collagen 1α1, collagen 3α1, and fibronectin and in principle pathway components associated with pulmonary fibrosis and hypoxia-mediated vascular remodeling: transforming growth factor (TGF)-β1, plasminogen activator inhibitor-1, hypoxia-inducible factor, and Nox4. TGF-β1 is a principle fibrotic mediator responsible for inducing up-regulation of profibrotic pathways associated with disease pathology. Using normal human lung-derived primary fibroblasts, we demonstrate that inhibition of Nox4 activity using a small molecule antagonist attenuates TGF-β1-mediated up-regulation in expression of profibrotic genes and inhibits the differentiation of fibroblast to myofibroblasts, that is associated with up-regulation in smooth muscle actin and acquisition of a contractile phenotype. These studies support the view that targeting Nox4 may provide a therapeutic approach for attenuating pulmonary fibrosis.
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Affiliation(s)
- Elizabeth R Jarman
- Respiratory Disease Area, Novartis Institutes for BioMedical Research, Horsham, West Sussex, United Kingdom
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57
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Miyata T, Ando T, Hiragi H, Watanabe K, Yamamoto F, Vaughan DE, Kurokawa T, Oshima Y, van Ypersele de Strihou C, Takeuchi M. Drug discovery in renal disease—towards a more efficient framework. Nat Rev Nephrol 2014; 10:290-6. [DOI: 10.1038/nrneph.2014.36] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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58
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Simone TM, Higgins CE, Czekay RP, Law BK, Higgins SP, Archambeault J, Kutz SM, Higgins PJ. SERPINE1: A Molecular Switch in the Proliferation-Migration Dichotomy in Wound-"Activated" Keratinocytes. Adv Wound Care (New Rochelle) 2014; 3:281-290. [PMID: 24669362 DOI: 10.1089/wound.2013.0512] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2013] [Accepted: 01/13/2014] [Indexed: 11/13/2022] Open
Abstract
Significance: A highly interactive serine protease/plasmin/matrix metalloproteinase axis regulates stromal remodeling in the wound microenvironment. Current findings highlight the importance of stringent controls on protease expression and their topographic activities in cell proliferation, migration, and tissue homeostasis. Targeting elements in this cascading network may lead to novel therapeutic approaches for fibrotic diseases and chronic wounds. Recent Advances: Matrix-active proteases and their inhibitors orchestrate wound site tissue remodeling, cell migration, and proliferation. Indeed, the serine proteases urokinase plasminogen activator and tissue-type plasminogen activator (uPA/tPA) and their major phsyiological inhibitor, plasminogen activator inhibitor-1 (PAI-1; serine protease inhibitor clade E member 1 [SERPINE1]), are upregulated in several cell types during injury repair. Coordinate expression of proteolytic enzymes and their inhibitors in the wound bed provides a mechanism for fine control of focal proteolysis to facilitate matrix restructuring and cell motility in complex environments. Critical Issues: Cosmetic and tissue functional consequences of wound repair anomalies affect the quality of life of millions of patients in the United States alone. The development of novel therapeutics to manage individuals most affected by healing anomalies will likely derive from the identification of critical, translationally accessible, control elements in the wound site microenvironment. Future Directions: Activation of the PAI-1 gene early after wounding, its prominence in the repair transcriptome and varied functions suggest a key role in the global cutaneous injury response program. Targeting PAI-1 gene expression and/or PAI-1 function with molecular genetic constructs, neutralizing antibodies or small molecule inhibitors may provide a novel, therapeutically relevant approach, to manage the pathophysiology of wound healing disorders associated with deficient or excessive PAI-1 levels.
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Affiliation(s)
- Tessa M. Simone
- Center for Cell Biology and Cancer Research, Albany Medical College, Albany, New York
| | - Craig E. Higgins
- Center for Cell Biology and Cancer Research, Albany Medical College, Albany, New York
| | - Ralf-Peter Czekay
- Center for Cell Biology and Cancer Research, Albany Medical College, Albany, New York
| | - Brian K. Law
- Department of Pharmacology and Therapeutics, University of Florida, Gainesville, Florida
| | - Stephen P. Higgins
- Center for Cell Biology and Cancer Research, Albany Medical College, Albany, New York
| | - Jaclyn Archambeault
- Center for Cell Biology and Cancer Research, Albany Medical College, Albany, New York
| | - Stacie M. Kutz
- Department of Biology, Sage College of Albany, Albany, New York
| | - Paul J. Higgins
- Center for Cell Biology and Cancer Research, Albany Medical College, Albany, New York
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59
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Simone TM, Higgins SP, Higgins CE, Lennartz MR, Higgins PJ. Chemical Antagonists of Plasminogen Activator Inhibitor-1: Mechanisms of Action and Therapeutic Potential in Vascular Disease. J Mol Genet Med 2014; 8. [PMID: 26110015 PMCID: PMC4476021 DOI: 10.4172/1747-0862.1000125] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Affiliation(s)
- Tessa M Simone
- Center for Cell Biology & Cancer Research, Albany Medical College, Albany, New York 12208, USA
| | - Stephen P Higgins
- Center for Cell Biology & Cancer Research, Albany Medical College, Albany, New York 12208, USA
| | - Craig E Higgins
- Center for Cell Biology & Cancer Research, Albany Medical College, Albany, New York 12208, USA
| | - Michelle R Lennartz
- 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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60
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Ghosh AK, Quaggin SE, Vaughan DE. Molecular basis of organ fibrosis: potential therapeutic approaches. Exp Biol Med (Maywood) 2013; 238:461-81. [PMID: 23856899 DOI: 10.1177/1535370213489441] [Citation(s) in RCA: 111] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Fibrosis, a non-physiological wound healing in multiple organs, is associated with end-stage pathological symptoms of a wide variety of vascular injury and inflammation related diseases. In response to chemical, immunological and physical insults, the body's defense system and matrix synthetic machinery respond to healing the wound and maintain tissue homeostasis. However, uncontrolled wound healing leads to scarring or fibrosis, a pathological condition characterized by excessive synthesis and accumulation of extracellular matrix proteins, loss of tissue homeostasis and organ failure. Understanding the actual cause of pathological wound healing and identification of igniter(s) of fibrogenesis would be helpful to design novel therapeutic approaches to control pathological wound healing and to prevent fibrosis related morbidity and mortality. In this article, we review the significance of a few key cytokines (TGF-β, IFN-γ, IL-10) transcriptional activators (Sp1, Egr-1, Smad3), repressors (Smad7, Fli-1, PPAR-γ, p53, Klotho) and epigenetic modulators (acetyltransferase, methyltransferases, deacetylases, microRNAs) involved in major matrix protein collagen synthesis under pathological stage of wound healing, and the potentiality of these regulators as therapeutic targets for fibrosis treatment. The significance of endothelial to mesenchymal transition (EndMT) and senescence, two newly emerged fields in fibrosis research, has also been discussed.
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Affiliation(s)
- Asish K Ghosh
- Feinberg Cardiovascular Research Institute & Division of Nephrology, Northwestern University, Chicago, IL, USA.
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61
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Florova G, Karandashova S, Declerck PJ, Idell S, Komissarov AA. Remarkable stabilization of plasminogen activator inhibitor 1 in a "molecular sandwich" complex. Biochemistry 2013; 52:4697-709. [PMID: 23734661 DOI: 10.1021/bi400470s] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Plasminogen activator inhibitor 1 (PAI-1) levels are elevated in a number of life-threatening conditions and often correlate with unfavorable outcomes. Spontaneous inactivation due to active to latent transition limits PAI-1 activity in vivo. While endogenous vitronectin (Vn) stabilizes PAI-1 by 1.5-2.0-fold, further stabilization occurs in a "molecular sandwich" complex (MSC) in which a ligand that restricts the exposed reactive center loop is bound to PAI-1/Vn. The effects of S195A two-chain urokinase (tcuPA) and Vn on inactivation of wild-type (wt) glycosylated (Gl-PAI-1), nonglycosylated (rPAI-1), and nonglycosylated Q123K PAI-1 (lacks Vn binding) forms were studied. S195A tcuPA decreased the rate constant (kL) for spontaneous inactivation at 37 °C for rPAI-1, Q123K, and Gl-PAI-1 by 6.7-, 3.4-, and 7.8-fold, respectively, and both S195A tcuPA and Vn by 66.7-, 5.5-, and 103.3-fold, respectively. Analysis of the temperature dependences of kL revealed a synergistic increase in the Gibbs free activation energy for spontaneous inactivation of wt Gl-PAI-1 and rPAI-1 in MSC from 99.8 and 96.1 to 111.3 and 107.0 kJ/mol, respectively, due to an increase in the activation enthalpy and a decrease in the activation entropy. Anti-PAI-1 monoclonal antibodies (mAbs) competing with proteinase also stabilize PAI-1/Vn. The rate of inhibition of target proteinases by MSCs, with a stoichiometry close to unity, was limited by the dissociation (k = 10(-4) to 10(-3) s(-1)) of S195A tcuPA or mAb. The stabilization of PAI-1 in MSCs in vivo may potentiate uncontrolled thrombosis or extravascular fibrin deposition, suggesting a new paradigm for using PAI-1 inhibitors and novel potential targets for therapy.
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Affiliation(s)
- Galina Florova
- Texas Lung Injury Institute, University of Texas Health Science Center at Tyler , 11937 U.S. Highway 271, Tyler, Texas 75708-3154, United States
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62
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Schuliga M, Westall G, Xia Y, Stewart AG. The plasminogen activation system: new targets in lung inflammation and remodeling. Curr Opin Pharmacol 2013; 13:386-93. [PMID: 23735578 DOI: 10.1016/j.coph.2013.05.014] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2013] [Revised: 05/14/2013] [Accepted: 05/14/2013] [Indexed: 11/26/2022]
Abstract
The plasminogen activation system (PAS) and the plasmin it forms have dual roles in chronic respiratory diseases including asthma, chronic obstructive pulmonary disease and interstitial lung disease. Whilst plasmin-mediated airspace fibrinolysis is beneficial, interstitial plasmin contributes to lung dysfunction because of its pro-inflammatory and tissue remodeling activities. Recent studies highlight the potential of fibrinolytic agents, including small molecule inhibitors of plasminogen activator inhibitor-1 (PAI-1), as treatments for chronic respiratory disease. Current data also suggest that interstitial urokinase plasminogen activator is an important mediator of lung inflammation and remodeling. However, further preclinical characterization of uPA as a drug target for lung disease is required. Here we review the concept of selectively targeting the contributions of PAS to treat chronic respiratory disease.
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Affiliation(s)
- Michael Schuliga
- Department of Pharmacol, University of Melbourne, Parkville, Victoria, Australia
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63
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McKleroy W, Lee TH, Atabai K. Always cleave up your mess: targeting collagen degradation to treat tissue fibrosis. Am J Physiol Lung Cell Mol Physiol 2013; 304:L709-21. [PMID: 23564511 PMCID: PMC3680761 DOI: 10.1152/ajplung.00418.2012] [Citation(s) in RCA: 161] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2012] [Accepted: 03/26/2013] [Indexed: 12/23/2022] Open
Abstract
Pulmonary fibrosis is a vexing clinical problem with no proven therapeutic options. In the normal lung there is continuous collagen synthesis and collagen degradation, and these two processes are precisely balanced to maintain normal tissue architecture. With lung injury there is an increase in the rate of both collagen production and collagen degradation. The increase in collagen degradation is critical in preventing the formation of permanent scar tissue each time the lung is exposed to injury. In pulmonary fibrosis, collagen degradation does not keep pace with collagen production, resulting in extracellular accumulation of fibrillar collagen. Collagen degradation occurs through both extracellular and intracellular pathways. The extracellular pathway involves cleavage of collagen fibrils by proteolytic enzyme including the metalloproteinases. The less-well-described intracellular pathway involves binding and uptake of collagen fragments by fibroblasts and macrophages for lysosomal degradation. The relationship between these two pathways and their relevance to the development of fibrosis is complex. Fibrosis in the lung, liver, and skin has been associated with an impaired degradative environment. Much of the current scientific effort in fibrosis is focused on understanding the pathways that regulate increased collagen production. However, recent reports suggest an important role for collagen turnover and degradation in regulating the severity of tissue fibrosis. The objective of this review is to evaluate the roles of the extracellular and intracellular collagen degradation pathways in the development of fibrosis and to examine whether pulmonary fibrosis can be viewed as a disease of impaired matrix degradation rather than a disease of increased matrix production.
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Affiliation(s)
- William McKleroy
- Cardiovascular Research Institute, Lung Biology Center, University of California San Francisco, San Francisco, CA 94158, USA
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64
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Fortenberry YM. Plasminogen activator inhibitor-1 inhibitors: a patent review (2006-present). Expert Opin Ther Pat 2013; 23:801-15. [PMID: 23521527 DOI: 10.1517/13543776.2013.782393] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
INTRODUCTION Plasminogen activator inhibitor-1 (PAI-1), the serine protease inhibitor (serpin), binds to and inhibits the plasminogen activators-tissue-type plasminogen activator (tPA) and the urokinase-type plasminogen activator (uPA). This results in both a decrease in plasmin production and a decrease in the dissolution of fibrin clots. Elevated levels of PAI-1 are correlated with an increased risk for cardiovascular disease and have been linked to obesity and metabolic syndrome. Consequently, the pharmacological suppression of PAI-1 might prevent or treat vascular disease. AREAS COVERED This article provides an overview of the patenting activity on PAI-1 inhibitors. Patents filed by pharmaceutical companies or individual research groups are described, and the biological and biochemical evaluation of the inhibitors, including in vitro and in vivo studies, is discussed. An overview of patents pertaining to using these inhibitors for treating various diseases is also included. EXPERT OPINION Although there is still no PAI-1 inhibitor being evaluated in a clinical setting or approved for human therapy, research in this field has progressed, and promising new compounds have been designed. Most research has focused on improving the pharmacological profile of these compounds, which will hopefully allow them to proceed to clinical studies. Despite the need for further testing and research, the potential use of PAI-1 inhibitors for treating cardiovascular disease appears quite promising.
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Affiliation(s)
- Yolanda M Fortenberry
- Johns Hopkins University School of Medicine, Division of Hematology/Department of Pediatrics, 720 Rutland Avenue Ross 1120, Baltimore, MD 21205, USA.
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65
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Zhang YP, Wang WL, Liu J, Li WB, Bai LL, Yuan YD, Song SX. Plasminogen activator inhibitor-1 promotes the proliferation and inhibits the apoptosis of pulmonary fibroblasts by Ca2+ signaling. Thromb Res 2013; 131:64-71. [DOI: 10.1016/j.thromres.2012.09.003] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2012] [Revised: 08/18/2012] [Accepted: 09/03/2012] [Indexed: 01/21/2023]
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66
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Samarakoon R, Overstreet JM, Higgins PJ. TGF-β signaling in tissue fibrosis: redox controls, target genes and therapeutic opportunities. Cell Signal 2012; 25:264-8. [PMID: 23063463 DOI: 10.1016/j.cellsig.2012.10.003] [Citation(s) in RCA: 269] [Impact Index Per Article: 22.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2012] [Accepted: 10/07/2012] [Indexed: 10/27/2022]
Abstract
During development of TGF-β1-initiated fibroproliferative disorders, NADPH oxidases (NOX family members) generate reactive oxygen species (ROS) resulting in downstream transcription of a subset genes encoding matrix structural elements and profibrotic factors. Prominent among the repertoire of disease-implicated genes is the TGF-β1 target gene encoding the potent profibrotic matricellular protein plasminogen activator inhibitor-1 (PAI-1 or SERPINE1). PAI-1 is the major physiologic inhibitor of the plasmin-based pericellular cascade and a causative factor in the development of vascular thrombotic and fibroproliferative disorders. ROS generation in response to TGF-β1 stimulation is rapid and precedes PAI-1 induction; engagement of non-SMAD (e.g., EGFR, Src kinase, MAP kinases, p53) and SMAD2/3 pathways are both required for PAI-1 expression and are ROS-dependent. Recent findings suggest a novel role for p53 in TGF-β1-induced PAI-1 transcription that involves ROS generation and p53/SMAD interactions. Targeting ROS and ROS-activated cellular events is likely to have therapeutic implications in the management of fibrotic disorders, particularly in the context of prolonged TGF-β1 signaling.
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Affiliation(s)
- Rohan Samarakoon
- Center for Cell Biology and Cancer Research, Albany Medical College, 47 New Scotland Avenue, Albany, NY 12208, USA
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Van De Craen B, Declerck PJ, Gils A. The Biochemistry, Physiology and Pathological roles of PAI-1 and the requirements for PAI-1 inhibition in vivo. Thromb Res 2012; 130:576-85. [DOI: 10.1016/j.thromres.2012.06.023] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2012] [Revised: 06/12/2012] [Accepted: 06/27/2012] [Indexed: 12/16/2022]
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Liu RM, Vayalil PK, Ballinger C, Dickinson DA, Huang WT, Wang S, Kavanagh TJ, Matthews QL, Postlethwait EM. Transforming growth factor β suppresses glutamate-cysteine ligase gene expression and induces oxidative stress in a lung fibrosis model. Free Radic Biol Med 2012; 53:554-63. [PMID: 22634145 PMCID: PMC3432394 DOI: 10.1016/j.freeradbiomed.2012.05.016] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/11/2012] [Revised: 04/03/2012] [Accepted: 05/09/2012] [Indexed: 01/01/2023]
Abstract
The concentration of glutathione (GSH), the most abundant intracellular free thiol and an important antioxidant, is decreased in the lung in both fibrotic diseases and experimental fibrosis models. The underlying mechanisms and biological significance of GSH depletion, however, remain unclear. Transforming growth factor β (TGF-β) is the most potent and ubiquitous profibrogenic cytokine and its expression is increased in almost all fibrotic diseases. In this study, we show that increasing TGF-β1 expression in mouse lung to a level comparable to those found in lung fibrotic diseases by intranasal instillation of AdTGF-β1(223/225), an adenovirus expressing constitutively active TGF-β1, suppressed the expression of both catalytic and modifier subunits of glutamate-cysteine ligase (GCL), the rate-limiting enzyme in de novo GSH synthesis, decreased GSH concentration, and increased protein and lipid peroxidation in mouse lung. Furthermore, we show that increasing TGF-β1 expression activated JNK and induced activating transcription factor 3, a transcriptional repressor involved in the regulation of the catalytic subunit of GCL, in mouse lung. Control virus (AdDL70-3) had no significant effect on any of these parameters, compared to saline-treated control. Concurrent with GSH depletion, TGF-β1 induced lung epithelial apoptosis and robust pulmonary fibrosis. Importantly, lung GSH levels returned to normal, whereas fibrosis persisted at least 21 days after TGF-β1 instillation. Together, the data suggest that increased TGF-β1 expression may contribute to the GSH depletion observed in pulmonary fibrosis diseases and that GSH depletion may be an early event in, rather than a consequence of, fibrosis development.
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Affiliation(s)
- Rui-Ming Liu
- Department of Environmental Health Sciences, School of Public Health, University of Alabama at Birmingham, AL 35294, USA.
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Osterholzer JJ, Christensen PJ, Lama V, Horowitz JC, Hattori N, Subbotina N, Cunningham A, Lin Y, Murdock BJ, Morey RE, Olszewski MA, Lawrence DA, Simon RH, Sisson TH. PAI-1 promotes the accumulation of exudate macrophages and worsens pulmonary fibrosis following type II alveolar epithelial cell injury. J Pathol 2012; 228:170-80. [PMID: 22262246 DOI: 10.1002/path.3992] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2011] [Revised: 12/12/2011] [Accepted: 01/12/2012] [Indexed: 01/16/2023]
Abstract
Fibrotic disorders of the lung are associated with perturbations in the plasminogen activation system. Specifically, plasminogen activator inhibitor-1 (PAI-1) expression is increased relative to the plasminogen activators. A direct role for this imbalance in modulating the severity of lung scarring following injury has been substantiated in the bleomycin model of pulmonary fibrosis. However, it remains unclear whether derangements in the plasminogen activation system contribute more generally to the pathogenesis of lung fibrosis beyond bleomycin injury. To answer this question, we employed an alternative model of lung scarring, in which type II alveolar epithelial cells (AECs) are specifically injured by administering diphtheria toxin (DT) to mice genetically engineered to express the human DT receptor (DTR) off the surfactant protein C promoter. This targeted AEC injury results in the diffuse accumulation of interstitial collagen. In the present study, we found that this targeted type II cell insult also increases PAI-1 expression in the alveolar compartment. We identified AECs and lung macrophages to be sources of PAI-1 production. To determine whether this elevated PAI-1 concentration was directly related to the severity of fibrosis, DTR(+) mice were crossed into a PAI-1-deficient background (DTR(+) : PAI-1(-/-) ). DT administration to DTR(+) : PAI-1(-/-) animals caused significantly less fibrosis than was measured in DTR(+) mice with intact PAI-1 production. PAI-1 deficiency also abrogated the accumulation of CD11b(+) exudate macrophages that were found to express PAI-1 and type-1 collagen. These observations substantiate the critical function of PAI-1 in pulmonary fibrosis pathogenesis and provide new insight into a potential mechanism by which this pro-fibrotic molecule influences collagen accumulation. Copyright © 2012 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
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Affiliation(s)
- John J Osterholzer
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI, USA
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