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Karki P, Li Y, Zhang CO, Ke Y, Promnares K, Birukova AA, Eggerman TL, Bocharov AV, Birukov KG. Amphipathic Helical Peptide L37pA Protects against Lung Vascular Endothelial Dysfunction Caused by Truncated Oxidized Phospholipids via Antagonism with CD36 Receptor. Am J Respir Cell Mol Biol 2024; 70:11-25. [PMID: 37725486 PMCID: PMC10768836 DOI: 10.1165/rcmb.2023-0127oc] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Accepted: 09/12/2023] [Indexed: 09/21/2023] Open
Abstract
The generation of bioactive truncated oxidized phospholipids (Tr-OxPLs) from oxidation of cell-membrane or circulating lipoproteins is a common feature of various pathological states. Scavenger receptor CD36 is involved in lipid transport and acts as a receptor for Tr-OxPLs. Interestingly, Tr-OxPLs and CD36 are involved in endothelial dysfunction-derived acute lung injury, but the precise mechanistic connections remain unexplored. In the present study, we investigated the role of CD36 in mediating pulmonary endothelial cell (EC) dysfunction caused by Tr-OxPLs. Our results demonstrated that the Tr-OxPLs KOdia-PC, Paz-PC, PGPC, PON-PC, POV-PC, and lysophosphocholine caused an acute EC barrier disruption as revealed by measurements of transendothelial electrical resistance and VE-cadherin immunostaining. More importantly, a synthetic amphipathic helical peptide, L37pA, targeting human CD36 strongly attenuated Tr-OxPL-induced EC permeability. L37pA also suppressed Tr-OxPL-induced endothelial inflammatory activation monitored by mRNA expression of inflammatory cytokines/chemokines and adhesion molecules. In addition, L37pA blocked Tr-OxPL-induced NF-κB activation and tyrosine phosphorylation of Src kinase and VE-cadherin. The Src inhibitor SU6656 attenuated KOdia-PC-induced EC permeability and inflammation, but inhibition of the Toll-like receptors (TLRs) TLR1, TLR2, TLR4, and TLR6 had no such protective effects. CD36-knockout mice were more resistant to Tr-OxPL-induced lung injury. Treatment with L37pA was equally effective in ameliorating Tr-OxPL-induced vascular leak and lung inflammation as determined by an Evans blue extravasation assay and total cell and protein content in BAL fluid. Altogether, these results demonstrate an essential role of CD36 in mediating Tr-OxPL-induced EC dysfunction and suggest a strong therapeutic potential of CD36 inhibitory peptides in mitigating lung injury and inflammation.
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Affiliation(s)
- Pratap Karki
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, and
| | - Yue Li
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, and
| | - Chen-Ou Zhang
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, and
| | - Yunbo Ke
- Department of Anesthesiology, University of Maryland School of Medicine, Baltimore, Maryland
| | - Kamoltip Promnares
- Department of Anesthesiology, University of Maryland School of Medicine, Baltimore, Maryland
| | - Anna A. Birukova
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, and
| | - Thomas L. Eggerman
- Department of Laboratory Medicine, Clinical Center, and
- National Institute of Diabetes, Digestive, and Kidney Diseases, National Institutes of Health, Bethesda, Maryland
| | | | - Konstantin G. Birukov
- Department of Anesthesiology, University of Maryland School of Medicine, Baltimore, Maryland
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Ramasubramanian B, Kim J, Ke Y, Li Y, Zhang CO, Promnares K, Tanaka KA, Birukov KG, Karki P, Birukova AA. Mechanisms of pulmonary endothelial permeability and inflammation caused by extracellular histone subunits H3 and H4. FASEB J 2022; 36:e22470. [PMID: 35969180 DOI: 10.1096/fj.202200303rr] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Revised: 07/04/2022] [Accepted: 07/14/2022] [Indexed: 11/11/2022]
Abstract
Extracellular DNA-binding proteins such as histones are danger-associated molecular pattern released by the injured tissues in trauma and sepsis settings, which trigger host immune response and vascular dysfunction. Molecular events leading to histone-induced endothelial cell (EC) dysfunction remain poorly understood. This study performed comparative analysis of H1, H2A, H2B, H3, and H4 histone subunits effects on human pulmonary EC permeability and inflammatory response. Analysis of transendothelial electrical resistance and EC monolayer permeability for macromolecues revealed that H3 and H4, but not H1, H2A, or H2B caused dose-dependent EC permeability accompanied by disassembly of adherens junctions. At higher doses, H3 and H4 activated nuclear factor kappa B inflammatory cascade leading to upregulation EC adhesion molecules ICAM1, VCAM1, E-selectin, and release of inflammatory cytokines. Inhibitory receptor analysis showed that toll-like receptor (TLR) 4 but not TLR1/2 or receptor for advanced glycation end inhibition significantly attenuated deleterious effects of H3 and H4 histones. Inhibitor of Rho-kinase was without effect, while inhibition of Src kinase caused partial preservation of cell-cell junctions, H3/H4-induced permeability and inflammation. Deleterious effects of H3/H4 were blocked by heparin. Activation of Epac-Rap1 signaling restored EC barrier properties after histone challenge. Intravenous injection of histones in mice caused elevation of inflammatory markers and increased vascular leak. Post-treatment with pharmacological Epac/Rap1 activator suppressed injurious effects of histones in vitro and in vivo. These results identify H3 and H4 as key histone subunits exhibiting deleterious effects on pulmonary vascular endothelium via TLR4-dependent mechanism. In conclusion, elevation of circulating histones may represent a serious risk of exacerbated acute lung injury (ALI) and multiple organ injury during severe trauma and infection.
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Affiliation(s)
- Baalachandran Ramasubramanian
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Junghyun Kim
- Department of Anesthesiology, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Yunbo Ke
- Department of Anesthesiology, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Yue Li
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Chen-Ou Zhang
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Kamoltip Promnares
- Department of Anesthesiology, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Kenichi A Tanaka
- Department of Anesthesiology, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Konstantin G Birukov
- Department of Anesthesiology, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Pratap Karki
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Anna A Birukova
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland, USA
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Kim J, Baalachandran R, Li Y, Zhang CO, Ke Y, Karki P, Birukov KG, Birukova AA. Circulating extracellular histones exacerbate acute lung injury by augmenting pulmonary endothelial dysfunction via TLR4-dependent mechanism. Am J Physiol Lung Cell Mol Physiol 2022; 323:L223-L239. [PMID: 35852995 PMCID: PMC9512107 DOI: 10.1152/ajplung.00072.2022] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Revised: 06/21/2022] [Accepted: 06/27/2022] [Indexed: 11/22/2022] Open
Abstract
Extracellular histones released into the circulation following trauma, sepsis, and ARDS may act as potent damage-associated molecular pattern signals leading to multiple organ failure. Endothelial cell (EC) dysfunction caused by extracellular histones has been demonstrated in vitro and in vivo; however, precise mechanistic details of histone-induced EC dysfunction and exacerbation of ongoing inflammation remain poorly understood. This study investigated the role of extracellular histones in exacerbating preexisting endothelial dysfunction and acute lung injury. Histone subunits H3 and H4, but not H1, H2A, or H2B, induced permeability in human pulmonary EC. H3 and H4 at concentrations above 30 µg/mL caused EC inflammation reflected by activation of the NF-κB pathway, transcriptional activation, and release of cytokines and chemokines including IL-6 and IL-8, and increased mRNA and protein expression of EC adhesion molecules VCAM-1 and ICAM-1. Pharmacological inhibitors targeting Toll-like receptor TLR4 but not TLR2/6, blocked histone-induced EC dysfunction. H3 and H4 also strongly augmented EC permeability and inflammation caused by Gram-negative and Gram-positive bacterial particles, endotoxin, and TNFα. Heparin blocked histone-induced augmentation of EC inflammation caused by endotoxin and TNFα. Injection of histone in mouse models of lung injury caused by bacterial wall lipopolysaccharide (LPS) and heat-killed Staphylococcus aureus (HKSA) augmented ALI parameters: increased protein content, cell count, and inflammatory cytokine secretion in bronchoalveolar lavage fluid. Important clinical significance of these findings is in the demonstration that even a modest increase in extracellular histone levels can act as a severe exacerbating factor in conjunction with other EC barrier disruptive or proinflammatory agents.
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Affiliation(s)
- Junghyun Kim
- Department of Anesthesiology, University of Maryland School of Medicine, Baltimore, Maryland
| | - Ramasubramanian Baalachandran
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland
| | - Yue Li
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland
| | - Chen-Ou Zhang
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland
| | - Yunbo Ke
- Department of Anesthesiology, University of Maryland School of Medicine, Baltimore, Maryland
| | - Pratap Karki
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland
| | - Konstantin G Birukov
- Department of Anesthesiology, University of Maryland School of Medicine, Baltimore, Maryland
| | - Anna A Birukova
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland
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Karki P, Birukov KG. Oxidized Phospholipids in Control of Endothelial Barrier Function: Mechanisms and Implication in Lung Injury. Front Endocrinol (Lausanne) 2021; 12:794437. [PMID: 34887839 PMCID: PMC8649713 DOI: 10.3389/fendo.2021.794437] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Accepted: 11/05/2021] [Indexed: 01/25/2023] Open
Abstract
Earlier studies investigating the pathogenesis of chronic vascular inflammation associated with atherosclerosis described pro-inflammatory and vascular barrier disruptive effects of lipid oxidation products accumulated in the sites of vascular lesion and atherosclerotic plaque. However, accumulating evidence including studies from our group suggests potent barrier protective and anti-inflammatory properties of certain oxidized phospholipids (OxPLs) in the lung vascular endothelium. Among these OxPLs, oxidized 1-palmitoyl-2-arachdonyl-sn-glycero-3-phosphocholine (OxPAPC) causes sustained enhancement of lung endothelial cell (EC) basal barrier properties and protects against vascular permeability induced by a wide variety of agonists ranging from bacterial pathogens and their cell wall components, endotoxins, thrombin, mechanical insults, and inflammatory cytokines. On the other hand, truncated OxPLs cause acute endothelial barrier disruption and potentiate inflammation. It appears that multiple signaling mechanisms triggering cytoskeletal remodeling are involved in OxPLs-mediated regulation of EC barrier. The promising vascular barrier protective and anti-inflammatory properties exhibited by OxPAPC and its particular components that have been established in the cellular and animal models of sepsis and acute lung injury has prompted consideration of OxPAPC as a prototype therapeutic molecule. In this review, we will summarize signaling and cytoskeletal mechanisms involved in OxPLs-mediated damage, rescue, and restoration of endothelial barrier in various pathophysiological settings and discuss a future potential of OxPAPC in treating lung disorders associated with endothelial barrier dysfunction.
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Affiliation(s)
- Pratap Karki
- Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Konstantin G. Birukov
- Department of Anesthesiology, University of Maryland School of Medicine, Baltimore, MD, United States
- *Correspondence: Konstantin G. Birukov,
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Haeberle H, Prohaska S, Martus P, Straub A, Zarbock A, Marx G, Zago M, Giera M, Koeppen M, Rosenberger P. Therapeutic iloprost for the treatment of acute respiratory distress syndrome (ARDS) (the ThIlo trial): a prospective, randomized, multicenter phase II study. Trials 2020; 21:242. [PMID: 32131881 PMCID: PMC7057516 DOI: 10.1186/s13063-020-4163-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Accepted: 02/12/2020] [Indexed: 01/08/2023] Open
Abstract
Background Acute respiratory distress syndrome (ARDS) is caused by rapid-onset (within hours) acute inflammatory processes in lung tissue, and it is a life-threatening condition with high mortality. The treatment of ARDS to date is focused on the prevention of further iatrogenic damage of the lung rather than the treatment of the initial inflammatory process. Several preclinical studies have revealed a beneficial effect of iloprost on the control of pulmonary inflammation, and in a small number of patients with ARDS, iloprost treatment resulted in improved oxygenation. Therefore, we plan to conduct a large multicenter trial to evaluate the effect of iloprost on ARDS. Methods The Therapeutic Iloprost during ARDS trial (ThIlo trial) is a multicenter, randomized, single blinded, clinical phase II trial assessing the efficacy of inhaled iloprost for the prevention of the development and progression of ARDS in critically ill patients. One hundred fifty critically ill patients suffering from acute ARDS will be treated either by nebulized iloprost or NaCl 0.9% for 5 days. Blood samples will be drawn at defined time points to elucidate the serum levels of iloprost and inflammatory markers during treatment. Mechanical ventilation will be standardized. In follow-up visits at days 28 and 90 as well as 6 months after enrollment, functional status according to the Barthel Index and a health care-related questionnaire, and frailty (Vulnerable Elders Survey) will be evaluated. The primary endpoint is the improvement of oxygenation, defined as the ratio of PaO2/FiO2. Secondary endpoints include 90-day all-cause mortality, Sequential Organ Failure Assessment scores during the study period up to day 90, the duration of mechanical ventilation, the length of intensive care unit (ICU) stay, ventilator-associated pneumonia, delirium, ICU-acquired weakness, and discharge localization. The study will be conducted in three university ARDS centers in Germany. Discussion The results of the ThIlo trial will highlight the anti-inflammatory effect of iloprost on early inflammatory processes during ARDS, resulting in the improvement of outcome parameters in patients with ARDS. Trial registration EUDRA-CT: 2016-003168-37. Registered on 12 April 2017. ClinicalTrials.gov: NCT03111212. Registered on 4 June 2017.
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Affiliation(s)
- Helene Haeberle
- Department of Anesthesiology and Intensive Care Medicine, University Hospital, Universitätsklinikum Tübingen, Universitätsklinikum Tübingen, Hoppe-Seyler-Straße 3, 72076, Tübingen, Germany.
| | - Stefanie Prohaska
- Department of Anesthesiology and Intensive Care Medicine, University Hospital, Universitätsklinikum Tübingen, Universitätsklinikum Tübingen, Hoppe-Seyler-Straße 3, 72076, Tübingen, Germany
| | - Peter Martus
- Institute for Clinical Epidemiology und Applied Biostatistics, Eberhard Karls University, Tübingen, Germany
| | - Andreas Straub
- Department of Anesthesiology and Intensive Care Medicine, University Hospital, Universitätsklinikum Tübingen, Universitätsklinikum Tübingen, Hoppe-Seyler-Straße 3, 72076, Tübingen, Germany
| | - Alexander Zarbock
- Department of Anesthesiology, Intensive Care Therapy and Pain Medicine, University Hospital Münster, Münster, Germany
| | - Gernot Marx
- Department of Intensive Care Medicine and Intermediate Care, University Hospital RWTH Aachen, Medical Faculty RWTH Aachen University, Aachen, Germany
| | - Manola Zago
- Center for Clinical Studies, University Hospital, Tübingen, Germany
| | - Martin Giera
- Center for Proteomics and Metabolomics, Leiden University Medical Center (LUMC), Leiden, The Netherlands
| | - Michael Koeppen
- Department of Anesthesiology and Intensive Care Medicine, University Hospital, Universitätsklinikum Tübingen, Universitätsklinikum Tübingen, Hoppe-Seyler-Straße 3, 72076, Tübingen, Germany
| | - Peter Rosenberger
- Department of Anesthesiology and Intensive Care Medicine, University Hospital, Universitätsklinikum Tübingen, Universitätsklinikum Tübingen, Hoppe-Seyler-Straße 3, 72076, Tübingen, Germany.
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6
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Young BM, Shankar K, Tho CK, Pellegrino AR, Heise RL. Laminin-driven Epac/Rap1 regulation of epithelial barriers on decellularized matrix. Acta Biomater 2019; 100:223-234. [PMID: 31593773 DOI: 10.1016/j.actbio.2019.10.009] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Revised: 10/03/2019] [Accepted: 10/03/2019] [Indexed: 12/28/2022]
Abstract
Decellularized tissues offer a unique tool for developing regenerative biomaterials or in vitro platforms for the study of cell-extracellular matrix (ECM) interactions. One main challenge associated with decellularized lung tissue is that ECM components can be stripped away or altered by the detergents used to remove cellular debris. Without characterizing the composition of lung decellularized ECM (dECM) and the cellular response caused by the altered composition, it is difficult to utilize dECM for regeneration and specifically, engineering the complexities of the alveolar-capillary barrier. This study takes steps towards uncovering if dECM must be enhanced with lost ECM proteins to achieve proper epithelial barrier formation. To achieve this, the epithelial barrier function was assessed on dECM coatings with and without the systematic addition of several key basement membrane proteins. After comparing barrier function on collagen I, fibronectin, laminin, and dECM in varying combinations as an in vitro coating, the alveolar epithelium exhibited superior barrier function when dECM was supplemented with laminin as evidenced by trans-epithelial electrical resistance (TEER) and permeability assays. Increased barrier resistance with laminin addition was associated with upregulation of Claudin-18, E-cadherin, and junction adhesion molecule (JAM)-A, and stabilization of zonula occludens (ZO)-1 at junction complexes. The Epac/Rap1 pathway was observed to play a role in the ECM-mediated barrier function determined by protein expression and Epac inhibition. These findings revealed potential ECM coatings and molecular therapeutic targets for improved regeneration with decellularized scaffolds. STATEMENT OF SIGNIFICANCE: Efforts to produce a transplantable organ-scale biomaterial for lung regeneration has not been entirely successful to date, due to incomplete cell-cell junction formation, ultimately leading to severe edema in vivo. To fully understand the process of alveolar junction formation on ECM-derived biomaterials, this research has characterized and tailored decellularized ECM (dECM) to mitigate reductions in barrier strength or cell attachment caused by abnormal ECM compositions or detergent damage to dECM. These results indicate that laminin-driven Epac signaling plays a vital role in the stabilization of the alveolar barrier. Addition of laminin or Epac agonists during alveolar regeneration can reduce epithelial permeability within bioengineered lungs.
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Affiliation(s)
- Bethany M Young
- Department of Biomedical Engineering, Virginia Commonwealth University, 800 E. Leigh St, Room 1071, Richmond, VA 23219, United States
| | - Keerthana Shankar
- Department of Biomedical Engineering, Virginia Commonwealth University, 800 E. Leigh St, Room 1071, Richmond, VA 23219, United States
| | - Cindy K Tho
- Department of Biomedical Engineering, Virginia Commonwealth University, 800 E. Leigh St, Room 1071, Richmond, VA 23219, United States
| | - Amanda R Pellegrino
- Department of Biomedical Engineering and Nursing, Duquesne University, 600 Forbes Ave, Pittsburg, Pennsylvania 15282, United States
| | - Rebecca L Heise
- Department of Biomedical Engineering, Virginia Commonwealth University, 800 E. Leigh St, Room 1071, Richmond, VA 23219, United States; Department of Physiology and Biophysics, Virginia Commonwealth University School of Medicine, 1101 East Marshall St, Richmond, Virginia 23298, United States.
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7
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Zemskov EA, Lu Q, Ornatowski W, Klinger CN, Desai AA, Maltepe E, Yuan JXJ, Wang T, Fineman JR, Black SM. Biomechanical Forces and Oxidative Stress: Implications for Pulmonary Vascular Disease. Antioxid Redox Signal 2019; 31:819-842. [PMID: 30623676 PMCID: PMC6751394 DOI: 10.1089/ars.2018.7720] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Significance: Oxidative stress in the cell is characterized by excessive generation of reactive oxygen species (ROS). Superoxide (O2-) and hydrogen peroxide (H2O2) are the main ROS involved in the regulation of cellular metabolism. As our fundamental understanding of the underlying causes of lung disease has increased it has become evident that oxidative stress plays a critical role. Recent Advances: A number of cells in the lung both produce, and respond to, ROS. These include vascular endothelial and smooth muscle cells, fibroblasts, and epithelial cells as well as the cells involved in the inflammatory response, including macrophages, neutrophils, eosinophils. The redox system is involved in multiple aspects of cell metabolism and cell homeostasis. Critical Issues: Dysregulation of the cellular redox system has consequential effects on cell signaling pathways that are intimately involved in disease progression. The lung is exposed to biomechanical forces (fluid shear stress, cyclic stretch, and pressure) due to the passage of blood through the pulmonary vessels and the distension of the lungs during the breathing cycle. Cells within the lung respond to these forces by activating signal transduction pathways that alter their redox state with both physiologic and pathologic consequences. Future Directions: Here, we will discuss the intimate relationship between biomechanical forces and redox signaling and its role in the development of pulmonary disease. An understanding of the molecular mechanisms induced by biomechanical forces in the pulmonary vasculature is necessary for the development of new therapeutic strategies.
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Affiliation(s)
- Evgeny A Zemskov
- Department of Medicine, The University of Arizona Health Sciences, Tucson, Arizona
| | - Qing Lu
- Department of Medicine, The University of Arizona Health Sciences, Tucson, Arizona
| | - Wojciech Ornatowski
- Department of Medicine, The University of Arizona Health Sciences, Tucson, Arizona
| | - Christina N Klinger
- Department of Medicine, The University of Arizona Health Sciences, Tucson, Arizona
| | - Ankit A Desai
- Department of Medicine, Indiana University, Indianapolis, Indiana
| | - Emin Maltepe
- Department of Pediatrics, University of California, San Francisco, San Francisco, California
| | - Jason X-J Yuan
- Department of Medicine, The University of Arizona Health Sciences, Tucson, Arizona
| | - Ting Wang
- Department of Internal Medicine, The University of Arizona Health Sciences, Phoenix, Arizona
| | - Jeffrey R Fineman
- Department of Pediatrics, University of California, San Francisco, San Francisco, California
| | - Stephen M Black
- Department of Medicine, The University of Arizona Health Sciences, Tucson, Arizona
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8
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Ke Y, Karki P, Zhang C, Li Y, Nguyen T, Birukov KG, Birukova AA. Mechanosensitive Rap1 activation promotes barrier function of lung vascular endothelium under cyclic stretch. Mol Biol Cell 2019; 30:959-974. [PMID: 30759056 PMCID: PMC6589902 DOI: 10.1091/mbc.e18-07-0422] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Mechanical ventilation remains an imperative treatment for the patients with acute respiratory distress syndrome, but can also exacerbate lung injury. We have previously described a key role of RhoA GTPase in high cyclic stretch (CS)-induced endothelial cell (EC) barrier dysfunction. However, cellular mechanotransduction complexes remain to be characterized. This study tested a hypothesis that recovery of a vascular EC barrier after pathologic mechanical stress may be accelerated by cell exposure to physiologic CS levels and involves Rap1-dependent rearrangement of endothelial cell junctions. Using biochemical, molecular, and imaging approaches we found that EC pre- or postconditioning at physiologically relevant low-magnitude CS promotes resealing of cell junctions disrupted by pathologic, high-magnitude CS. Cytoskeletal remodeling induced by low CS was dependent on small GTPase Rap1. Protective effects of EC preconditioning at low CS were abolished by pharmacological or molecular inhibition of Rap1 activity. In vivo, using mice exposed to mechanical ventilation, we found that the protective effect of low tidal volume ventilation against lung injury caused by lipopolysaccharides and ventilation at high tidal volume was suppressed in Rap1 knockout mice. Taken together, our results demonstrate a prominent role of Rap1-mediated signaling mechanisms activated by low CS in acceleration of lung vascular EC barrier restoration.
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Affiliation(s)
- Yunbo Ke
- Department of Anesthesiology, University of Maryland School of Medicine, Baltimore, MD 21201
| | - Pratap Karki
- Department of Medicine, University of Maryland School of Medicine, Baltimore, MD 21201
| | - Chenou Zhang
- Department of Medicine, University of Maryland School of Medicine, Baltimore, MD 21201
| | - Yue Li
- Department of Medicine, University of Maryland School of Medicine, Baltimore, MD 21201
| | - Trang Nguyen
- Department of Medicine, University of Maryland School of Medicine, Baltimore, MD 21201
| | - Konstantin G. Birukov
- Department of Anesthesiology, University of Maryland School of Medicine, Baltimore, MD 21201
| | - Anna A. Birukova
- Department of Medicine, University of Maryland School of Medicine, Baltimore, MD 21201,*Address correspondence to: Anna A. Birukova ()
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Fang Y, Wu D, Birukov KG. Mechanosensing and Mechanoregulation of Endothelial Cell Functions. Compr Physiol 2019; 9:873-904. [PMID: 30873580 PMCID: PMC6697421 DOI: 10.1002/cphy.c180020] [Citation(s) in RCA: 107] [Impact Index Per Article: 21.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Vascular endothelial cells (ECs) form a semiselective barrier for macromolecules and cell elements regulated by dynamic interactions between cytoskeletal elements and cell adhesion complexes. ECs also participate in many other vital processes including innate immune reactions, vascular repair, secretion, and metabolism of bioactive molecules. Moreover, vascular ECs represent a unique cell type exposed to continuous, time-dependent mechanical forces: different patterns of shear stress imposed by blood flow in macrovasculature and by rolling blood cells in the microvasculature; circumferential cyclic stretch experienced by the arterial vascular bed caused by heart propulsions; mechanical stretch of lung microvascular endothelium at different magnitudes due to spontaneous respiration or mechanical ventilation in critically ill patients. Accumulating evidence suggests that vascular ECs contain mechanosensory complexes, which rapidly react to changes in mechanical loading, process the signal, and develop context-specific adaptive responses to rebalance the cell homeostatic state. The significance of the interactions between specific mechanical forces in the EC microenvironment together with circulating bioactive molecules in the progression and resolution of vascular pathologies including vascular injury, atherosclerosis, pulmonary edema, and acute respiratory distress syndrome has been only recently recognized. This review will summarize the current understanding of EC mechanosensory mechanisms, modulation of EC responses to humoral factors by surrounding mechanical forces (particularly the cyclic stretch), and discuss recent findings of magnitude-specific regulation of EC functions by transcriptional, posttranscriptional and epigenetic mechanisms using -omics approaches. We also discuss ongoing challenges and future opportunities in developing new therapies targeting dysregulated mechanosensing mechanisms to treat vascular diseases. © 2019 American Physiological Society. Compr Physiol 9:873-904, 2019.
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Affiliation(s)
- Yun Fang
- Department of Medicine, University of Chicago, Chicago, Illinois, USA,Correspondence to
| | - David Wu
- Department of Medicine, University of Chicago, Chicago, Illinois, USA
| | - Konstantin G. Birukov
- Department of Anesthesiology, University of Maryland Baltimore School of Medicine, Baltimore, Maryland, USA
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Abstract
Edema is typically presented as a secondary effect from injury, illness, disease, or medication, and its impact on patient wellness is nested within the underlying etiology. Therefore, it is often thought of more as an amplifier to current preexisting conditions. Edema, however, can be an independent risk factor for patient deterioration. Improper management of edema is costly not only to the patient, but also to treatment and care facilities, as mismanagement of edema results in increased lengths of hospital stay. Direct tissue trauma, disease, or inappropriate resuscitation and/or ventilation strategies result in edema formation through physical disruption and chemical messenger-based structural modifications of the microvascular barrier. Derangements in microvascular barrier function limit tissue oxygenation, nutrient flow, and cellular waste removal. Recent studies have sought to elucidate cellular signaling and structural alterations that result in vascular hyperpermeability in a variety of critical care conditions to include hemorrhage, burn trauma, and sepsis. These studies and many others have highlighted how multiple mechanisms alter paracellular and/or transcellular pathways promoting hyperpermeability. Roles for endothelial glycocalyx, extracellular matrix and basement membrane, vesiculo-vacuolar organelles, cellular junction and cytoskeletal proteins, and vascular pericytes have been described, demonstrating the complexity of microvascular barrier regulation. Understanding these basic mechanisms inside and out of microvessels aid in developing better treatment strategies to mitigate the harmful effects of excessive edema formation.
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11
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Incorporation of iloprost in phospholipase-resistant phospholipid scaffold enhances its barrier protective effects on pulmonary endothelium. Sci Rep 2018; 8:879. [PMID: 29343759 PMCID: PMC5772615 DOI: 10.1038/s41598-018-19197-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Accepted: 12/27/2017] [Indexed: 12/15/2022] Open
Abstract
Correction of barrier dysfunction and inflammation in acute lung injury (ALI) represents an important problem. Previous studies demonstrate barrier-protective and anti-inflammatory effects of bioactive lipid prostacyclin and its stable analog iloprost (ILO). We generated a phospholipase resistant synthetic phospholipid with iloprost attached at the sn-2 position (ILO-PC) and investigated its biological effects. In comparison to free ILO, ILO-PC caused sustained endothelial cell (EC) barrier enhancement, linked to more prolonged activation of Rap1 and Rac1 GTPases and their cytoskeletal and cell junction effectors: cortactin, PAK1, p120-catenin and VE-cadherin. ILO and ILO-PC equally efficiently suppressed acute, Rho GTPase-dependent EC hyper-permeability caused by thrombin. However, ILO-PC exhibited more sustained barrier-protective and anti-inflammatory effects in the model of chronic EC dysfunction caused by bacterial wall lipopolysacharide (LPS). ILO-PC was also more potent inhibitor of NFκB signaling and lung vascular leak in the murine model of LPS-induced ALI. Treatment with ILO-PC showed more efficient ALI recovery over 3 days after LPS challenge than free ILO. In conclusion, this study describes a novel synthetic phospholipid with barrier-enhancing and anti-inflammatory properties superior to existing prostacyclin analogs, which may be used as a prototype for future development of more efficient treatment for ALI and other vascular leak syndromes.
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12
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Birukov KG, Karki P. Injured lung endothelium: mechanisms of self-repair and agonist-assisted recovery (2017 Grover Conference Series). Pulm Circ 2017; 8:2045893217752660. [PMID: 29261029 PMCID: PMC6022073 DOI: 10.1177/2045893217752660] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The lung endothelium is vulnerable to both exogenous and endogenous insults, so a properly coordinated efficient repair system is essential for the timely recovery of the lung after injury. The agents that cause endothelial injury and dysfunction fall into a broad range from mechanical forces such as pathological cyclic stretch and shear stress to bacterial pathogens and their virulent components, vasoactive agonists including thrombin and histamine, metabolic causes including high glucose and oxidized low-density lipoprotein (OxLDL), circulating microparticles, and inflammatory cytokines. The repair mechanisms employed by endothelial cells (EC) can be broadly categorized into three groups: (1) intrinsic mechanism of recovery regulated by the cross-talk between small GTPases as exemplified by Rap1-mediated EC barrier recovery from Rho-mediated thrombin-induced EC hyperpermeability; (2) agonist-assisted recovery facilitated by the activation of Rac and Rap1 with subsequent inhibition of Rho signaling as observed with many barrier protective agonists including oxidized phospholipids, sphingosine 1-phosphate, prostacyclins, and hepatocyte growth factor; and (3) self-recovery of EC by the secretion of growth factors and other pro-survival bioactive compounds including anti-inflammatory molecules such as lipoxins during the resolution of inflammation. In this review, we will discuss the molecular and cellular mechanisms of pulmonary endothelium repair that is critical for the recovery from various forms of lung injuries.
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Affiliation(s)
- Konstantin G. Birukov
- Department of Anesthesiology, University of
Maryland Baltimore, School of Medicine, Baltimore, MD, USA,Konstantin G. Birukov, Department of Anesthesiology,
University of Maryland, School of Medicine, 20 Penn Street, HSF-2, Room 145 Baltimore, MD
21201, USA.
| | - Pratap Karki
- Division of Pulmonary and Critical Care
Medicine, Department of Medicine, University of Maryland Baltimore, School of Medicine,
Baltimore, MD, USA
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13
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Abstract
Lipid mediators play a critical role in the development and resolution of vascular endothelial barrier dysfunction caused by various pathologic interventions. The accumulation of excess lipids directly impairs endothelial cell (EC) barrier function that is known to contribute to the development of atherosclerosis and metabolic disorders such as obesity and diabetes as well as chronic inflammation in the vascular endothelium. Certain products of phospholipid oxidation (OxPL) such as fragmented phospholipids generated during oxidative and nitrosative stress show pro-inflammatory potential and cause endothelial barrier dysfunction. In turn, other OxPL products enhance basal EC barrier and exhibit potent barrier-protective effects in pathologic settings of acute vascular leak caused by pro-inflammatory mediators, barrier disruptive agonists and pathologic mechanical stimulation. These beneficial effects were further confirmed in rodent models of lung injury and inflammation. The bioactive oxidized lipid molecules may serve as important therapeutic prototype molecules for future treatment of acute lung injury syndromes associated with endothelial barrier dysfunction and inflammation. This review will summarize recent studies of biological effects exhibited by various groups of lipid mediators with a focus on the role of oxidized phospholipids in control of vascular endothelial barrier, agonist induced EC permeability, inflammation, and barrier recovery related to clinical settings of acute lung injury and inflammatory vascular leak.
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Affiliation(s)
- Pratap Karki
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, University of Maryland Baltimore, School of Medicine, Baltimore, MD, USA
| | - Konstantin G. Birukov
- Department of Anesthesiology, University of Maryland Baltimore, School of Medicine, Baltimore, MD, USA,CONTACT Konstantin G. Birukov, MD, PhD Department of Anesthesiology, University of Maryland, School of Medicine, 20 Penn Street, HSF-2, Room 145, Baltimore, MD 21201, USA
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14
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Tundup S, Kandasamy M, Perez JT, Mena N, Steel J, Nagy T, Albrecht RA, Manicassamy B. Endothelial cell tropism is a determinant of H5N1 pathogenesis in mammalian species. PLoS Pathog 2017; 13:e1006270. [PMID: 28282445 PMCID: PMC5362246 DOI: 10.1371/journal.ppat.1006270] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Revised: 03/22/2017] [Accepted: 03/02/2017] [Indexed: 12/19/2022] Open
Abstract
The cellular and molecular mechanisms underpinning the unusually high virulence of highly pathogenic avian influenza H5N1 viruses in mammalian species remains unknown. Here, we investigated if the cell tropism of H5N1 virus is a determinant of enhanced virulence in mammalian species. We engineered H5N1 viruses with restricted cell tropism through the exploitation of cell type-specific microRNA expression by incorporating microRNA target sites into the viral genome. Restriction of H5N1 replication in endothelial cells via miR-126 ameliorated disease symptoms, prevented systemic viral spread and limited mortality, despite showing similar levels of peak viral replication in the lungs as compared to control virus-infected mice. Similarly, restriction of H5N1 replication in endothelial cells resulted in ameliorated disease symptoms and decreased viral spread in ferrets. Our studies demonstrate that H5N1 infection of endothelial cells results in excessive production of cytokines and reduces endothelial barrier integrity in the lungs, which culminates in vascular leakage and viral pneumonia. Importantly, our studies suggest a need for a combinational therapy that targets viral components, suppresses host immune responses, and improves endothelial barrier integrity for the treatment of highly pathogenic H5N1 virus infections. In healthy individuals, the symptoms of seasonal influenza virus infection are mild and the infection is cleared within 4–7 days. However, infection with highly pathogenic avian influenza virus (H5N1) can be severe and often results in fatal pneumonia even in healthy adults. While it is known that both viral and host factors play a role in enhanced disease progression, the molecular mechanisms for the high virulence of H5N1 virus are not completely understood. In this study, we engineered avian influenza H5N1 viruses incapable of replicating in endothelial cells and evaluated disease symptoms in mice and ferrets. Our studies show that H5N1 infection of endothelial cells causes severe disease and death of infected animals in part due to the damage of endothelial cells lining the blood vessels, which results in leakage of fluid into the lungs (pneumonia).
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Affiliation(s)
- Smanla Tundup
- Department of Microbiology, University of Chicago, Chicago, IL, United States of America
- Howard Taylor Ricketts Laboratory, University of Chicago, Argonne, IL, United States of America
| | - Matheswaran Kandasamy
- Department of Microbiology, University of Chicago, Chicago, IL, United States of America
- Howard Taylor Ricketts Laboratory, University of Chicago, Argonne, IL, United States of America
| | - Jasmine T. Perez
- Department of Microbiology, University of Chicago, Chicago, IL, United States of America
| | - Nacho Mena
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY, United States of America
| | - John Steel
- Department of Microbiology, Emory University, Atlanta, GA, United States of America
| | - Tamas Nagy
- Comparative Pathology Laboratory, University of Georgia, Athens, GA, United States of America
| | - Randy A. Albrecht
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY, United States of America
| | - Balaji Manicassamy
- Department of Microbiology, University of Chicago, Chicago, IL, United States of America
- Howard Taylor Ricketts Laboratory, University of Chicago, Argonne, IL, United States of America
- * E-mail:
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15
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Aman J, Weijers EM, van Nieuw Amerongen GP, Malik AB, van Hinsbergh VWM. Using cultured endothelial cells to study endothelial barrier dysfunction: Challenges and opportunities. Am J Physiol Lung Cell Mol Physiol 2016; 311:L453-66. [PMID: 27343194 DOI: 10.1152/ajplung.00393.2015] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2015] [Accepted: 06/20/2016] [Indexed: 12/24/2022] Open
Abstract
Despite considerable progress in the understanding of endothelial barrier regulation and the identification of approaches that have the potential to improve endothelial barrier function, no drug- or stem cell-based therapy is presently available to reverse the widespread vascular leak that is observed in acute respiratory distress syndrome (ARDS) and sepsis. The translational gap suggests a need to develop experimental approaches and tools that better mimic the complex environment of the microcirculation in which the vascular leak develops. Recent studies have identified several elements of this microenvironment. Among these are composition and stiffness of the extracellular matrix, fluid shear stress, interaction of endothelial cells (ECs) with pericytes, oxygen tension, and the combination of toxic and mechanic injurious stimuli. Development of novel cell culture techniques that integrate these elements would allow in-depth analysis of EC biology that closely approaches the (patho)physiological conditions in situ. In parallel, techniques to isolate organ-specific ECs, to define EC heterogeneity in its full complexity, and to culture patient-derived ECs from inducible pluripotent stem cells or endothelial progenitor cells are likely to advance the understanding of ARDS and lead to development of therapeutics. This review 1) summarizes the advantages and pitfalls of EC cultures to study vascular leak in ARDS, 2) provides an overview of elements of the microvascular environment that can directly affect endothelial barrier function, and 3) discusses alternative methods to bridge the gap between basic research and clinical application with the intent of improving the translational value of present EC culture approaches.
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Affiliation(s)
- Jurjan Aman
- Department of Physiology, Institute for Cardiovascular Research, VU University Medical Center, Amsterdam, The Netherlands; Department of Pulmonary Diseases, Institute for Cardiovascular Research, VU University Medical Center, Amsterdam, The Netherlands;
| | - Ester M Weijers
- Department of Physiology, Institute for Cardiovascular Research, VU University Medical Center, Amsterdam, The Netherlands
| | - Geerten P van Nieuw Amerongen
- Department of Physiology, Institute for Cardiovascular Research, VU University Medical Center, Amsterdam, The Netherlands
| | - Asrar B Malik
- Department of Pharmacology, University of Illinois College of Medicine, Chicago, Illinois
| | - Victor W M van Hinsbergh
- Department of Physiology, Institute for Cardiovascular Research, VU University Medical Center, Amsterdam, The Netherlands
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16
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Meliton A, Meng F, Tian Y, Shah AA, Birukova AA, Birukov KG. Role of Krev Interaction Trapped-1 in Prostacyclin-Induced Protection against Lung Vascular Permeability Induced by Excessive Mechanical Forces and Thrombin Receptor Activating Peptide 6. Am J Respir Cell Mol Biol 2016; 53:834-43. [PMID: 25923142 DOI: 10.1165/rcmb.2014-0376oc] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Mechanisms of vascular endothelial cell (EC) barrier regulation during acute lung injury (ALI) or other pathologies associated with increased vascular leakiness are an active area of research. Adaptor protein krev interaction trapped-1 (KRIT1) participates in angiogenesis, lumen formation, and stabilization of EC adherens junctions (AJs) in mature vasculature. We tested a role of KRIT1 in the regulation of Rho-GTPase signaling induced by mechanical stimulation and barrier dysfunction relevant to ventilator-induced lung injury and investigated KRIT1 involvement in EC barrier protection by prostacyclin (PC). PC stimulated Ras-related protein 1 (Rap1)-dependent association of KRIT1 with vascular endothelial cadherin at AJs, with KRIT1-dependent cortical cytoskeletal remodeling leading to EC barrier enhancement. KRIT1 knockdown exacerbated Rho-GTPase activation and EC barrier disruption induced by pathologic 18% cyclic stretch and thrombin receptor activating peptide (TRAP) 6 and attenuated the protective effects of PC. In the two-hit model of ALI caused by high tidal volume (HTV) mechanical ventilation and TRAP6 injection, KRIT1 functional deficiency in KRIT1(+/-) mice increased basal lung vascular leak and augmented vascular leak and lung injury caused by exposure to HTV and TRAP6. Down-regulation of KRIT1 also diminished the protective effects of PC against TRAP6/HTV-induced lung injury. These results demonstrate a KRIT1-dependent mechanism of vascular EC barrier control in basal conditions and in the two-hit model of ALI caused by excessive mechanical forces and TRAP6 via negative regulation of Rho activity and enhancement of cell junctions. We also conclude that the stimulation of the Rap1-KRIT1 signaling module is a major mechanism of vascular endothelial barrier protection by PC in the injured lung.
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Affiliation(s)
- Angelo Meliton
- Lung Injury Center and Section of Pulmonary and Critical Care Medicine, Department of Medicine, University of Chicago, Chicago, Illinois
| | - Fanyong Meng
- Lung Injury Center and Section of Pulmonary and Critical Care Medicine, Department of Medicine, University of Chicago, Chicago, Illinois
| | - Yufeng Tian
- Lung Injury Center and Section of Pulmonary and Critical Care Medicine, Department of Medicine, University of Chicago, Chicago, Illinois
| | - Alok A Shah
- Lung Injury Center and Section of Pulmonary and Critical Care Medicine, Department of Medicine, University of Chicago, Chicago, Illinois
| | - Anna A Birukova
- Lung Injury Center and Section of Pulmonary and Critical Care Medicine, Department of Medicine, University of Chicago, Chicago, Illinois
| | - Konstantin G Birukov
- Lung Injury Center and Section of Pulmonary and Critical Care Medicine, Department of Medicine, University of Chicago, Chicago, Illinois
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17
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Tian Y, Gawlak G, O'Donnell JJ, Birukova AA, Birukov KG. Activation of Vascular Endothelial Growth Factor (VEGF) Receptor 2 Mediates Endothelial Permeability Caused by Cyclic Stretch. J Biol Chem 2016; 291:10032-45. [PMID: 26884340 DOI: 10.1074/jbc.m115.690487] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Indexed: 01/28/2023] Open
Abstract
High tidal volume mechanical ventilation and the resultant excessive mechanical forces experienced by lung vascular endothelium are known to lead to increased vascular endothelial leak, but the underlying molecular mechanisms remain incompletely understood. One reported mechanotransduction pathway of increased endothelial cell (EC) permeability caused by high magnitude cyclic stretch (18% CS) involves CS-induced activation of the focal adhesion associated signalosome, which triggers Rho GTPase signaling. This study identified an alternative pathway of CS-induced EC permeability. We show here that high magnitude cyclic stretch (18% CS) rapidly activates VEGF receptor 2 (VEGFR2) signaling by dissociating VEGFR2 from VE-cadherin at the cell junctions. This results in VEGFR2 activation, Src-dependent VE-cadherin tyrosine phosphorylation, and internalization leading to increased endothelial permeability. This process is also accompanied by CS-induced phosphorylation and internalization of PECAM1. Importantly, CS-induced endothelial barrier disruption was attenuated by VEGFR2 inhibition. 18% CS-induced EC permeability was linked to dissociation of cell junction scaffold afadin from the adherens junctions. Forced expression of recombinant afadin in pulmonary endothelium attenuated CS-induced VEGFR2 and VE-cadherin phosphorylation, preserved adherens junction integrity and VEGFR2·VE-cadherin complex, and suppressed CS-induced EC permeability. This study shows for the first time a mechanism whereby VEGFR2 activation mediates EC permeability induced by pathologically relevant cyclic stretch. In this mechanism, CS induces dissociation of the VE-cadherin·VEGFR2 complex localized at the adherens juctions, causing activation of VEGFR2, VEGFR2-mediated Src-dependent phosphorylation of VE-cadherin, disassembly of adherens junctions, and EC barrier failure.
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Affiliation(s)
- Yufeng Tian
- From the Lung Injury Center and Section of Pulmonary and Critical Care Medicine, Department of Medicine, University of Chicago, Chicago, Illinois 60637
| | - Grzegorz Gawlak
- From the Lung Injury Center and Section of Pulmonary and Critical Care Medicine, Department of Medicine, University of Chicago, Chicago, Illinois 60637
| | - James J O'Donnell
- From the Lung Injury Center and Section of Pulmonary and Critical Care Medicine, Department of Medicine, University of Chicago, Chicago, Illinois 60637
| | - Anna A Birukova
- From the Lung Injury Center and Section of Pulmonary and Critical Care Medicine, Department of Medicine, University of Chicago, Chicago, Illinois 60637
| | - Konstantin G Birukov
- From the Lung Injury Center and Section of Pulmonary and Critical Care Medicine, Department of Medicine, University of Chicago, Chicago, Illinois 60637
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18
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Huang Y, Tan Q, Chen R, Cao B, Li W. Sevoflurane prevents lipopolysaccharide-induced barrier dysfunction in human lung microvascular endothelial cells: Rho-mediated alterations of VE-cadherin. Biochem Biophys Res Commun 2015; 468:119-24. [PMID: 26529544 DOI: 10.1016/j.bbrc.2015.10.150] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2015] [Accepted: 10/28/2015] [Indexed: 12/24/2022]
Abstract
Acute lung injury (ALI) mainly occurs as increased permeability of lung tissue and pleural effusion. Inhaled anesthetic sevoflurane has been demonstrated to alleviate lung permeability by upregulating junction proteins after ischemia-reperfusion. However, the exact mechanisms of its protective effect on reperfusion injury remain elusive. The aim of this study was to assess possible preconditioning with sevoflurane in an in vitro model of lipopolysaccharide (LPS)-induced barrier dysfunction in human lung microvascular endothelial cells (HMVEC-Ls). In this study, HMVEC-Ls were exposed to minimum alveolar concentration of sevoflurane for 2 h. LPS significantly increased the permeability of HMVEC-L. Moreover, the distribution of junction protein, vascular endothelial (VE)-cadherin, in cell-cell junction area and the total expression in HMVEC-Ls were significantly decreased by LPS treatment. However, the abnormal distribution and decreased expression of VE-cadherin and hyperpermeability of HMVEC-Ls were significantly reversed by pretreatment with sevoflurane. Furthermore, LPS-induced activation of the RhoA/ROCK signaling pathway was significantly inhibited with sevoflurane. Such activation, abnormal distribution and decreased expression of VE-cadherin and hyperpermeability of HMVEC-Ls were significantly inhibited with sevoflurane pretreatment or knockdown of RhoA or ROCK-2. In conclusion, sevoflurane prevented LPS-induced rupture of HMVEC-L monolayers by suppressing the RhoA/ROCK-mediated VE-cadherin signaling pathway. Our results may explain, at least in part, some beneficial effects of sevoflurane on pulmonary dysfunction such as ischemia-reperfusion injury.
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Affiliation(s)
- Yiran Huang
- Department of Anesthesiology, The 157 Affiliated Hospital, General Hospital of Guangzhou Military Command of PLA, Guangzhou 510510, PR China.
| | - Qindong Tan
- Department of Anesthesiology, Xiangya Hospital, Central South University, Changsha, 410008 Hunan, PR China
| | - Rui Chen
- Department of Anesthesiology, The 157 Affiliated Hospital, General Hospital of Guangzhou Military Command of PLA, Guangzhou 510510, PR China
| | - Biao Cao
- Department of Anesthesiology, The 157 Affiliated Hospital, General Hospital of Guangzhou Military Command of PLA, Guangzhou 510510, PR China
| | - Wenhong Li
- Department of Anesthesiology, The 157 Affiliated Hospital, General Hospital of Guangzhou Military Command of PLA, Guangzhou 510510, PR China
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19
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Konya V, Maric J, Jandl K, Luschnig P, Aringer I, Lanz I, Platzer W, Theiler A, Bärnthaler T, Frei R, Marsche G, Marsh LM, Olschewski A, Lippe IT, Heinemann A, Schuligoi R. Activation of EP 4 receptors prevents endotoxin-induced neutrophil infiltration into the airways and enhances microvascular barrier function. Br J Pharmacol 2015; 172:4454-4468. [PMID: 26103450 DOI: 10.1111/bph.13229] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2014] [Revised: 06/16/2015] [Accepted: 06/16/2015] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND AND PURPOSE Pulmonary vascular dysfunction is a key event in acute lung injury. We recently demonstrated that PGE2 , via activation of E-prostanoid (EP)4 receptors, strongly enhances microvascular barrier function in vitro. The aim of this study was to investigate the beneficial effects of concomitant EP4 receptor activation in murine models of acute pulmonary inflammation. EXPERIMENTAL APPROACH Pulmonary inflammation in male BALB/c mice was induced by LPS (20 μg per mouse intranasally) or oleic acid (0.15 μL·g-1 , i.v. ). In-vitro, endothelial barrier function was determined by measuring electrical impedance. KEY RESULTS PGE2 activation of EP4 receptors reduced neutrophil infiltration, pulmonary vascular leakage and TNF-α concentration in bronchoalveolar lavage fluid from LPS-induced pulmonary inflammation. Similarly, pulmonary vascular hyperpermeability induced by oleic acid was counteracted by EP4 receptor activation. In lung function assays, the EP4 agonist ONO AE1-329 restored the increased resistance and reduced compliance upon methacholine challenge in mice treated with LPS or oleic acid. In agreement with these findings, EP4 receptor activation increased the in vitro vascular barrier function of human and mouse pulmonary microvascular endothelial cells and diminished the barrier disruption induced by LPS. The EP2 agonist ONO AE1-259 likewise reversed LPS-induced lung dysfunction without enhancing vascular barrier function. CONCLUSION AND IMPLICATIONS Our results show that activation of the EP4 receptor strengthens the microvascular barrier function and thereby ameliorates the pathology of acute lung inflammation, including neutrophil infiltration, vascular oedema formation and airway dysfunction. This suggests a potential benefit for EP4 agonists in acute pulmonary inflammation.
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Affiliation(s)
- V Konya
- Institute of Experimental and Clinical Pharmacology, Medical University of Graz, Graz, Austria
| | - J Maric
- Institute of Experimental and Clinical Pharmacology, Medical University of Graz, Graz, Austria
| | - K Jandl
- Institute of Experimental and Clinical Pharmacology, Medical University of Graz, Graz, Austria
| | - P Luschnig
- Institute of Experimental and Clinical Pharmacology, Medical University of Graz, Graz, Austria
| | - I Aringer
- Institute of Experimental and Clinical Pharmacology, Medical University of Graz, Graz, Austria.,Clinical Division of Nephrology, Department of Internal Medicine, Medical University of Graz, Graz, Austria
| | - I Lanz
- Institute of Experimental and Clinical Pharmacology, Medical University of Graz, Graz, Austria
| | - W Platzer
- Institute of Experimental and Clinical Pharmacology, Medical University of Graz, Graz, Austria
| | - A Theiler
- Institute of Experimental and Clinical Pharmacology, Medical University of Graz, Graz, Austria
| | - T Bärnthaler
- Institute of Experimental and Clinical Pharmacology, Medical University of Graz, Graz, Austria
| | - R Frei
- Institute of Experimental and Clinical Pharmacology, Medical University of Graz, Graz, Austria
| | - G Marsche
- Institute of Experimental and Clinical Pharmacology, Medical University of Graz, Graz, Austria
| | - L M Marsh
- Ludwig Boltzmann Institute for Lung Vascular Research, Graz, Austria
| | - A Olschewski
- Ludwig Boltzmann Institute for Lung Vascular Research, Graz, Austria
| | - I T Lippe
- Institute of Experimental and Clinical Pharmacology, Medical University of Graz, Graz, Austria
| | - A Heinemann
- Institute of Experimental and Clinical Pharmacology, Medical University of Graz, Graz, Austria
| | - R Schuligoi
- Institute of Experimental and Clinical Pharmacology, Medical University of Graz, Graz, Austria
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20
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Yang J, Yao W, Qian G, Wei Z, Wu G, Wang G. Rab5-mediated VE-cadherin internalization regulates the barrier function of the lung microvascular endothelium. Cell Mol Life Sci 2015; 72:4849-66. [PMID: 26112597 PMCID: PMC4827161 DOI: 10.1007/s00018-015-1973-4] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2015] [Revised: 06/15/2015] [Accepted: 06/17/2015] [Indexed: 12/21/2022]
Abstract
The small GTPase Rab5 has been well defined to control the vesicle-mediated plasma membrane protein transport to the endosomal compartment. However, its function in the internalization of vascular endothelial (VE)-cadherin, an important component of adherens junctions, and as a result regulating the endothelial cell polarity and barrier function remain unknown. Here, we demonstrated that lipopolysaccharide (LPS) simulation markedly enhanced the activation and expression of Rab5 in human pulmonary microvascular endothelial cells (HPMECs), which is accompanied by VE-cadherin internalization. In parallel, LPS challenge also induced abnormal cell polarity and dysfunction of the endothelial barrier in HPMECs. LPS stimulation promoted the translocation of VE-cadherin from the plasma membrane to intracellular compartments, and intracellularly expressed VE-cadherin was extensively colocalized with Rab5. Small interfering RNA (siRNA)-mediated depletion of Rab5a expression attenuated the disruption of LPS-induced internalization of VE-cadherin and the disorder of cell polarity. Furthermore, knockdown of Rab5 inhibited the vascular endothelial hyperpermeability and protected endothelial barrier function from LPS injury, both in vitro and in vivo. These results suggest that Rab5 is a critical mediator of LPS-induced endothelial barrier dysfunction, which is likely mediated through regulating VE-cadherin internalization. These findings provide evidence, implicating that Rab5a is a potential therapeutic target for preventing endothelial barrier disruption and vascular inflammation.
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Affiliation(s)
- Junjun Yang
- Institute of Respiratory Diseases and Critical Care, Xinqiao Hospital, Third Military Medical University, Chongqing, 400037, China
| | - Wei Yao
- Institute of Respiratory Diseases and Critical Care, Xinqiao Hospital, Third Military Medical University, Chongqing, 400037, China
| | - Guisheng Qian
- Institute of Respiratory Diseases and Critical Care, Xinqiao Hospital, Third Military Medical University, Chongqing, 400037, China
| | - Zhenghua Wei
- Institute of Respiratory Diseases and Critical Care, Xinqiao Hospital, Third Military Medical University, Chongqing, 400037, China
| | - Guangyu Wu
- Department of Pharmacology and Toxicology, Medical College of Georgia, Georgia Regents University, 1459 Laney Walker Blvd., Augusta, GA, 30912, USA.
| | - Guansong Wang
- Institute of Respiratory Diseases and Critical Care, Xinqiao Hospital, Third Military Medical University, Chongqing, 400037, China.
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21
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Birukova AA, Meng F, Tian Y, Meliton A, Sarich N, Quilliam LA, Birukov KG. Prostacyclin post-treatment improves LPS-induced acute lung injury and endothelial barrier recovery via Rap1. Biochim Biophys Acta Mol Basis Dis 2014; 1852:778-91. [PMID: 25545047 DOI: 10.1016/j.bbadis.2014.12.016] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2014] [Revised: 12/15/2014] [Accepted: 12/22/2014] [Indexed: 12/27/2022]
Abstract
Protective effects of prostacyclin (PC) or its stable analog beraprost against agonist-induced lung vascular inflammation have been associated with elevation of intracellular cAMP and Rac GTPase signaling which inhibited the RhoA GTPase-dependent pathway of endothelial barrier dysfunction. This study investigated a distinct mechanism of PC-stimulated lung vascular endothelial (EC) barrier recovery and resolution of LPS-induced inflammation mediated by small GTPase Rap1. Efficient barrier recovery was observed in LPS-challenged pulmonary EC after prostacyclin administration even after 15 h of initial inflammatory insult and was accompanied by the significant attenuation of p38 MAP kinase and NFκB signaling and decreased production of IL-8 and soluble ICAM1. These effects were reproduced in cells post-treated with 8CPT, a small molecule activator of Rap1-specific nucleotide exchange factor Epac. By contrast, pharmacologic Epac inhibitor, Rap1 knockdown, or knockdown of cell junction-associated Rap1 effector afadin attenuated EC recovery caused by PC or 8CPT post-treatment. The key role of Rap1 in lung barrier restoration was further confirmed in the murine model of LPS-induced acute lung injury. Lung injury was monitored by measurements of bronchoalveolar lavage protein content, cell count, and Evans blue extravasation and live imaging of vascular leak over 6 days using a fluorescent tracer. The data showed significant acceleration of lung recovery by PC and 8CPT post-treatment, which was abrogated in Rap1a(-/-) mice. These results suggest that post-treatment with PC triggers the Epac/Rap1/afadin-dependent mechanism of endothelial barrier restoration and downregulation of p38MAPK and NFκB inflammatory cascades, altogether leading to accelerated lung recovery.
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Affiliation(s)
- Anna A Birukova
- Lung Injury Center, Section of Pulmonary and Critical Medicine, Department of Medicine, University of Chicago, Chicago, IL 60637, USA
| | - Fanyong Meng
- Lung Injury Center, Section of Pulmonary and Critical Medicine, Department of Medicine, University of Chicago, Chicago, IL 60637, USA
| | - Yufeng Tian
- Lung Injury Center, Section of Pulmonary and Critical Medicine, Department of Medicine, University of Chicago, Chicago, IL 60637, USA
| | - Angelo Meliton
- Lung Injury Center, Section of Pulmonary and Critical Medicine, Department of Medicine, University of Chicago, Chicago, IL 60637, USA
| | - Nicolene Sarich
- Lung Injury Center, Section of Pulmonary and Critical Medicine, Department of Medicine, University of Chicago, Chicago, IL 60637, USA
| | - Lawrence A Quilliam
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN 46202-5122, USA
| | - Konstantin G Birukov
- Lung Injury Center, Section of Pulmonary and Critical Medicine, Department of Medicine, University of Chicago, Chicago, IL 60637, USA.
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The role of 8-oxoguanine DNA glycosylase-1 in inflammation. Int J Mol Sci 2014; 15:16975-97. [PMID: 25250913 PMCID: PMC4200771 DOI: 10.3390/ijms150916975] [Citation(s) in RCA: 75] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2014] [Revised: 09/09/2014] [Accepted: 09/16/2014] [Indexed: 12/12/2022] Open
Abstract
Many, if not all, environmental pollutants/chemicals and infectious agents increase intracellular levels of reactive oxygen species (ROS) at the site of exposure. ROS not only function as intracellular signaling entities, but also induce damage to cellular molecules including DNA. Among the several dozen ROS-induced DNA base lesions generated in the genome, 8-oxo-7,8-dihydroguanine (8-oxoG) is one of the most abundant because of guanine’s lowest redox potential among DNA bases. In mammalian cells, 8-oxoG is repaired by the 8-oxoguanine DNA glycosylase-1 (OGG1)-initiated DNA base excision repair pathway (OGG1–BER). Accumulation of 8-oxoG in DNA has traditionally been associated with mutagenesis, as well as various human diseases and aging processes, while the free 8-oxoG base in body fluids is one of the best biomarkers of ongoing pathophysiological processes. In this review, we discuss the biological significance of the 8-oxoG base and particularly the role of OGG1–BER in the activation of small GTPases and changes in gene expression, including those that regulate pro-inflammatory chemokines/cytokines and cause inflammation.
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Ibuprofen protects ventilator-induced lung injury by downregulating Rho-kinase activity in rats. BIOMED RESEARCH INTERNATIONAL 2014; 2014:749097. [PMID: 25019086 PMCID: PMC4075182 DOI: 10.1155/2014/749097] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/16/2014] [Revised: 05/15/2014] [Accepted: 05/19/2014] [Indexed: 12/20/2022]
Abstract
Background. Ventilator-induced lung injury-(VILI-) induced endothelial permeability is regulated through the Rho-dependent signaling pathway. Ibuprofen inhibits Rho activation in animal models of spinal-cord injury and Alzheimer's disease. The study aims to investigate ibuprofen effects on high tidal volume associated VILI. Methods. Twenty-eight adult male Sprague-Dawley rats were randomized to receive a ventilation strategy with three different interventions for 2 h: (1) a high-volume zero-positive end-expiratory pressure (PEEP) (HVZP) group; (2) an HVZP + ibuprofen 15 mg/kg group; and (3) an HVZP + ibuprofen 30 mg/kg group. A fourth group without ventilation served as the control group. Rho-kinase activity was determined by ratio of phosphorylated ezrin, radixin, and moesin (p-ERM), substrates of Rho-kinase, to total ERM. VILI was characterized by increased pulmonary protein leak, wet-to-dry weight ratio, cytokines level, and Rho guanine nucleotide exchange factor (GEF-H1), RhoA activity, p-ERM/total ERM, and p-myosin light chain (MLC) protein expression. Results. Ibuprofen pretreatment significantly reduced the HVZP ventilation-induced increase in pulmonary protein leak, wet-to-dry weight ratio, bronchoalveolar lavage fluid interleukin-6 and RANTES levels, and lung GEF-H1, RhoA activity, p-ERM/total ERM, and p-MLC protein expression. Conclusion. Ibuprofen attenuated high tidal volume induced pulmonary endothelial hyperpermeability. This protective effect was associated with a reduced Rho-kinase activity.
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Tian X, Tian Y, Gawlak G, Sarich N, Wu T, Birukova AA. Control of vascular permeability by atrial natriuretic peptide via a GEF-H1-dependent mechanism. J Biol Chem 2013; 289:5168-83. [PMID: 24352660 DOI: 10.1074/jbc.m113.493924] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Microtubule (MT) dynamics is involved in a variety of cell functions, including control of the endothelial cell (EC) barrier. Release of Rho-specific nucleotide exchange factor GEF-H1 from microtubules activates the Rho pathway of EC permeability. In turn, pathologic vascular leak can be prevented by treatment with atrial natriuretic peptide (ANP). This study investigated a novel mechanism of vascular barrier protection by ANP via modulation of GEF-H1 function. In pulmonary ECs, ANP suppressed thrombin-induced disassembly of peripheral MT and attenuated Rho signaling and cell retraction. ANP effects were mediated by the Rac1 GTPase effector PAK1. Activation of Rac1-PAK1 promoted PAK1 interaction with the Rho activator GEF-H1, inducing phosphorylation of total and MT-bound GEF-H1 and leading to attenuation of Rho-dependent actin remodeling. In vivo, ANP attenuated lung injury caused by excessive mechanical ventilation and TRAP peptide (TRAP/HTV), which was further exacerbated in ANP(-/-) mice. The protective effects of ANP against TRAP/HTV-induced lung injury were linked to the increased pool of stabilized MT and inactivation of Rho signaling via ANP-induced, PAK1-dependent inhibitory phosphorylation of GEF-H1. This study demonstrates a novel protective mechanism of ANP against pathologic hyperpermeability and suggests a novel pharmacological intervention for the prevention of increased vascular leak via PAK1-dependent modulation of GEF-H1 activity.
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Affiliation(s)
- Xinyong Tian
- From the Lung Injury Center, Section of Pulmonary and Critical Medicine, Department of Medicine, University of Chicago, Chicago, Illinois 60637
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Abstract
Increased endothelial permeability and reduction of alveolar liquid clearance capacity are two leading pathogenic mechanisms of pulmonary edema, which is a major complication of acute lung injury, severe pneumonia, and acute respiratory distress syndrome, the pathologies characterized by unacceptably high rates of morbidity and mortality. Besides the success in protective ventilation strategies, no efficient pharmacological approaches exist to treat this devastating condition. Understanding of fundamental mechanisms involved in regulation of endothelial permeability is essential for development of barrier protective therapeutic strategies. Ongoing studies characterized specific barrier protective mechanisms and identified intracellular targets directly involved in regulation of endothelial permeability. Growing evidence suggests that, although each protective agonist triggers a unique pattern of signaling pathways, selected common mechanisms contributing to endothelial barrier protection may be shared by different barrier protective agents. Therefore, understanding of basic barrier protective mechanisms in pulmonary endothelium is essential for selection of optimal treatment of pulmonary edema of different etiology. This article focuses on mechanisms of lung vascular permeability, reviews major intracellular signaling cascades involved in endothelial monolayer barrier preservation and summarizes a current knowledge regarding recently identified compounds which either reduce pulmonary endothelial barrier disruption and hyperpermeability, or reverse preexisting lung vascular barrier compromise induced by pathologic insults.
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Affiliation(s)
- Konstantin G Birukov
- Lung Injury Center, Section of Pulmonary and Critical Care, Department of Medicine, University of Chicago, Chicago, Illinois, USA.
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Abstract
Mechanical ventilation (MV) is, by definition, the application of external forces to the lungs. Depending on their magnitude, these forces can cause a continuum of pathophysiological alterations ranging from the stimulation of inflammation to the disruption of cell-cell contacts and cell membranes. These side effects of MV are particularly relevant for patients with inhomogeneously injured lungs such as in acute lung injury (ALI). These patients require supraphysiological ventilation pressures to guarantee even the most modest gas exchange. In this situation, ventilation causes additional strain by overdistension of the yet non-injured region, and additional stress that forms because of the interdependence between intact and atelectatic areas. Cells are equipped with elaborate mechanotransduction machineries that respond to strain and stress by the activation of inflammation and repair mechanisms. Inflammation is the fundamental response of the host to external assaults, be they of mechanical or of microbial origin and can, if excessive, injure the parenchymal tissue leading to ALI. Here, we will discuss the forces generated by MV and how they may injure the lungs mechanically and through inflammation. We will give an overview of the mechanotransduction and how it leads to inflammation and review studies demonstrating that ventilator-induced lung injury can be prevented by blocking pathways of mechanotransduction or inflammation.
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Affiliation(s)
- Ulrike Uhlig
- Department of Pharmacology & Toxicology, Medical Faculty, RWTH Aachen University, Aachen, Germany
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Storck EM, Wojciak-Stothard B. Rho GTPases in pulmonary vascular dysfunction. Vascul Pharmacol 2013; 58:202-10. [DOI: 10.1016/j.vph.2012.09.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2012] [Revised: 09/05/2012] [Accepted: 09/09/2012] [Indexed: 12/19/2022]
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Kuebler WM. Eisenmenger's Syndrome: In Search of the Best Vasodilator. Cardiology 2013; 126:252-4. [DOI: 10.1159/000354937] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/18/2013] [Accepted: 07/18/2013] [Indexed: 11/19/2022]
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Birukova AA, Tian Y, Dubrovskyi O, Zebda N, Sarich N, Tian X, Wang Y, Birukov KG. VE-cadherin trans-interactions modulate Rac activation and enhancement of lung endothelial barrier by iloprost. J Cell Physiol 2012; 227:3405-16. [PMID: 22213015 DOI: 10.1002/jcp.24041] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Small GTPase Rac is important regulator of endothelial cell (EC) barrier enhancement by prostacyclin characterized by increased peripheral actin cytoskeleton and increased interactions between VE-cadherin and other adherens junction (AJ) proteins. This study utilized complementary approaches including siRNA knockdown, culturing in Ca(2+) -free medium, and VE-cadherin blocking antibody to alter VE-cadherin extracellular interactions to investigate the role of VE-cadherin outside-in signaling in modulation of Rac activation and EC barrier regulation by prostacyclin analog iloprost. Spatial analysis of Rac activation in pulmonary EC by FRET revealed additional spike in iloprost-induced Rac activity at the sites of newly formed cell-cell junctions. In contrast, disruption of VE-cadherin extracellular trans-interactions suppressed iloprost-activated Rac signaling and attenuated EC barrier enhancement and cytoskeletal remodeling. These inhibitory effects were associated with decreased membrane accumulation and activation of Rac-specific guanine nucleotide exchange factors (GEFs) Tiam1 and Vav2. Conversely, plating of pulmonary EC on surfaces coated with extracellular VE-cadherin domain further promoted iloprost-induced Rac signaling. In the model of thrombin-induced EC barrier recovery, blocking of VE-cadherin trans-interactions attenuated activation of Rac pathway during recovery phase and delayed suppression of Rho signaling and restoration of EC barrier properties. These results suggest that VE-cadherin outside-in signaling controls locally Rac activity stimulated by barrier protective agonists. This control is essential for maximal EC barrier enhancement and accelerated barrier recovery.
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Affiliation(s)
- Anna A Birukova
- Lung Injury Center, Section of Pulmonary and Critical Medicine, Department of Medicine, University of Chicago, Chicago, IL 60637, USA.
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Ren Y, Guo L, Tang X, Apparsundaram S, Kitson C, Deguzman J, Fuentes ME, Coyle L, Majmudar R, Allard J, Truitt T, Hamid R, Chen Y, Qian Y, Budd DC. Comparing the differential effects of LPA on the barrier function of human pulmonary endothelial cells. Microvasc Res 2012; 85:59-67. [PMID: 23084965 DOI: 10.1016/j.mvr.2012.10.004] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2012] [Revised: 10/08/2012] [Accepted: 10/09/2012] [Indexed: 02/08/2023]
Abstract
Lysophosphatidic acid (LPA) is a class of bioactive lyso-phospholipid that mediates most of its biological effects through a family of G protein-coupled receptors of which six have been identified. The role of the LPA pathway in driving chronic lung diseases such as idiopathic pulmonary fibrosis (IPF) has gained considerable academic and industry attention. Modulation of the pulmonary artery endothelial barrier function by the LPA1 receptor has been shown to drive pulmonary fibrosis in murine models of disease. The purpose of this study was (i) to assess the effect of LPA on the barrier function of human pulmonary arterial (HPAEC) and microvascular (HMVEC) endothelial cells and (ii) to identify the LPA receptor subtype(s) responsible for changes in human pulmonary endothelial cell permeability using LPA receptor antagonists and siRNA technology. Analysis of the LPA receptor subtype expression demonstrated predominant expression of LPA2 and LPA6 receptor subtypes in both HPAECs and HMVECs. HPAECs also exhibit low expression of LPA1, LPA3, and LPA4 receptor subtypes. Treatment of cells with increasing concentrations of LPA caused loss of barrier function in HPAECs but not HMVECs, despite both cell types exhibiting very similar LPA receptor expression profiles. The LPA-mediated loss of barrier function in HPAECs appears to be independent of the LPA1 receptor and likely to be mediated via the LPA6 receptor although we cannot exclude an additional role for the LPA2 and LPA4 receptors in mediating these effects. These results suggest cell-specific mechanisms exist in human pulmonary endothelial cells to permit regulation of barrier function downstream of LPA receptors. More importantly, our data indicate that selective LPA1 receptor antagonism may be insufficient for therapeutic use in pulmonary diseases where impaired endothelial barrier function is related to disease initiation and progression.
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Affiliation(s)
- Yonglin Ren
- Inflammation Discovery Therapeutic Area, Hoffmann-La Roche Inc., Nutley, NJ 07110-1199, USA
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Tian X, Tian Y, Sarich N, Wu T, Birukova AA. Novel role of stathmin in microtubule-dependent control of endothelial permeability. FASEB J 2012; 26:3862-74. [PMID: 22700873 DOI: 10.1096/fj.12-207746] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Microtubule (MT) dynamics in vascular endothelium are modulated by vasoactive mediators and are critically involved in the control of endothelial cell (EC) permeability via Rho GTPase-dependent crosstalk with the actin cytoskeleton. However, the role of regulators in MT stability in these mechanisms remains unclear. This study investigated the involvement of the MT-associated protein stathmin in the mediation of agonist-induced permeability in EC cultures and vascular leak in vivo. Thrombin treatment of human pulmonary ECs induced rapid dephosphorylation and activation of stathmin. Inhibition of stathmin activity by small interfering RNA-based knockdown or cAMP-mediated phosphorylation abrogated thrombin-induced F-actin remodeling and Rho-dependent EC hyperpermeability, while expression of a phosphorylation-deficient stathmin mutant exacerbated thrombin-induced EC barrier disruption. Stathmin suppression preserved the MT network against thrombin-induced MT disassembly and release of Rho-specific guanine nucleotide exchange factor, GEF-H1. The protective effects of stathmin knockdown were observed in vivo in the mouse 2-hit model of ventilator-induced lung injury and were linked to MT stabilization and down-regulation of Rho signaling in the lung. These results demonstrate the mechanism of stathmin-dependent control of MT dynamics, Rho signaling, and permeability and suggest novel potential pharmacological interventions in the prevention of increased vascular leak via modulation of stathmin activity.
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Affiliation(s)
- Xinyong Tian
- Lung Injury Center, Section of Pulmonary and Critical Medicine, Department of Medicine, University of Chicago, Chicago, Illinois 60637, USA
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Robertson JA, Sauer D, Gold JA, Nonas SA. The role of cyclooxygenase-2 in mechanical ventilation-induced lung injury. Am J Respir Cell Mol Biol 2012; 47:387-94. [PMID: 22556158 DOI: 10.1165/rcmb.2011-0005oc] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Mechanical ventilation is necessary for patients with acute respiratory failure, but can cause or propagate lung injury. We previously identified cyclooxygenase-2 as a candidate gene in mechanical ventilation-induced lung injury. Our objective was to determine the role of cyclooxygenase-2 in mechanical ventilation-induced lung injury and the effects of cyclooxygenase-2 inhibition on lung inflammation and barrier disruption. Mice were mechanically ventilated at low and high tidal volumes, in the presence or absence of pharmacologic cyclooxygenase-2-specific inhibition with 3-(4-methylsulphonylphenyl)-4-phenyl-5-trifluoromethylisoxazole (CAY10404). Lung injury was assessed using markers of alveolar-capillary leakage and lung inflammation. Cyclooxygenase-2 expression and activity were measured by Western blotting, real-time PCR, and lung/plasma prostanoid analysis, and tissue sections were analyzed for cyclooxygenase-2 staining by immunohistochemistry. High tidal volume ventilation induced lung injury, significantly increasing both lung leakage and lung inflammation relative to control and low tidal volume ventilation. High tidal volume mechanical ventilation significantly induced cyclooxygenase-2 expression and activity, both in the lungs and systemically, compared with control mice and low tidal volume mice. The immunohistochemical analysis of lung sections localized cyclooxygenase-2 expression to monocytes and macrophages in the alveoli. The pharmacologic inhibition of cyclooxygenase-2 with CAY10404 significantly decreased cyclooxygenase activity and attenuated lung injury in mice ventilated at high tidal volume, attenuating barrier disruption, tissue inflammation, and inflammatory cell signaling. This study demonstrates the induction of cyclooxygenase-2 by mechanical ventilation, and suggests that the therapeutic inhibition of cyclooxygenase-2 may attenuate ventilator-induced acute lung injury.
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Affiliation(s)
- Joshua A Robertson
- Division of Pulmonary and Critical Care, Oregon Health and Science University, Portland, OR 97239, USA
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Abstract
PURPOSE OF REVIEW Ventilator-induced lung injury (VILI) is a ubiquitous iatrogenic clinical problem in critical care. Aside from avoiding large tidal volumes, little progress has been made in identifying effective clinical strategies to minimize this injury. With recent rapid development in bioinformatics and high-throughput molecular technology, the genetic basis of lung injury has been intensively investigated. This review will describe recent insights and potential therapies developed in the field. RECENT FINDINGS Much progress has been made in delineating the possible genes and gene products involved in VILI through various mechanisms such as early induced genes, capillary leak, apoptosis, fibrin deposition, inflammatory cytokines, oxidative stress, disrupted angiogenesis, and neutrophil infiltration. Some studies have translated bench findings to the bedside in an attempt to identify clinically important genetic susceptibility, which could aid in the identification of at-risk individuals who might benefit from careful titration of mechanical ventilation. Genetic insights also provide candidate pharmaceutical approaches that may ameliorate VILI in the future. SUMMARY Much relevant information exists for investigators and clinicians interested in VILI. Future research will interlink evolving data to provide a more integrated picture of the molecular mechanisms involved in VILI enabling translation of the most promising candidate therapies.
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Birukova AA, Tian Y, Meliton A, Leff A, Wu T, Birukov KG. Stimulation of Rho signaling by pathologic mechanical stretch is a "second hit" to Rho-independent lung injury induced by IL-6. Am J Physiol Lung Cell Mol Physiol 2012; 302:L965-75. [PMID: 22345573 DOI: 10.1152/ajplung.00292.2011] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Most patients with acute lung injury (ALI) and acute respiratory distress syndrome of septic and nonseptic nature require assisted ventilation with positive pressure, which at suboptimal range may further exacerbate lung dysfunction. Previous studies described enhancement of agonist-induced Rho GTPase signaling and endothelial cell (EC) permeability in EC cultures exposed to pathologically relevant cyclic stretch (CS) magnitudes. This study examined a role of pathologic CS in modulation of pulmonary EC permeability caused by IL-6, a cytokine increased in sepsis and acting in a Rho-independent manner. IL-6 increased EC permeability, which was associated with activation of Jak/signal transducers and activators of transcription, p38 MAP kinase, and NF-κB signaling and was augmented by EC exposure to 18% CS. Rho kinase inhibitor Y-27632 suppressed the synergistic effect of 18% CS on IL-6-induced EC monolayer disruption but did not alter the IL-6 effects on static EC culture. 18% CS also increased IL-6-induced ICAM-1 expression by pulmonary EC and neutrophil adhesion, which was attenuated by Y-27632. Intratracheal IL-6 administration in C57BL/6J mice increased protein content and cell count in bronchoalveolar lavage fluid. These changes were augmented by high tidal volume mechanical ventilation (HTV; 30 ml/kg, 4 h). Intravenous injection of Y-27632 suppressed IL6/HTV-induced lung injury. In conclusion, this study proposes a novel mechanism contributing to two-hit model of ALI: in addition to synergistic effects on Rho-dependent endothelial hyper-permeability triggered by thrombin, TNFα, LPS, or other agonists, ventilator-induced lung injury-relevant CS may also exacerbate Rho-independent mechanisms of EC permeability induced by other inflammatory mediators such as IL-6 via mechanisms involving Rho activity.
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Affiliation(s)
- Anna A Birukova
- Lung Injury Center, Section of Pulmonary and Critical Medicine, Dept. of Medicine, Univ. of Chicago, Chicago, IL 60637, USA
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DiPaolo BC, Margulies SS. Rho kinase signaling pathways during stretch in primary alveolar epithelia. Am J Physiol Lung Cell Mol Physiol 2012; 302:L992-1002. [PMID: 22287611 DOI: 10.1152/ajplung.00175.2011] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Alveolar epithelial cells (AECs) maintain integrity of the blood-gas barrier with actin-anchored intercellular tight junctions. Stretched type I-like AECs undergo magnitude- and frequency-dependent actin cytoskeletal remodeling into perijunctional actin rings. On the basis of published studies in human pulmonary artery endothelial cells (HPAECs), we hypothesize that RhoA activity, Rho kinase (ROCK) activity, and phosphorylation of myosin light chain II (MLC2) increase in stretched type I-like AECs in a manner that is dependent on stretch magnitude, and that RhoA, ROCK, or MLC2 activity inhibition will attenuate stretch-induced actin remodeling and preserve barrier properties. Primary type I-like AEC monolayers were stretched biaxially to create a change in surface area (ΔSA) of 12%, 25%, or 37% in a cyclic manner at 0.25 Hz for up to 60 min or left unstretched. Type I-like AECs were also treated with Rho pathway inhibitors (ML-7, Y-27632, or blebbistatin) and stained for F-actin or treated with the myosin phosphatase inhibitor calyculin-A and quantified for monolayer permeability. Counter to our hypothesis, ROCK activity and MLC2 phosphorylation decreased in type I-like AECs stretched to 25% and 37% ΔSA and did not change in monolayers stretched to 12% ΔSA. Furthermore, RhoA activity decreased in type I-like AECs stretched to 37% ΔSA. In contrast, MLC2 phosphorylation in HPAECs increased when HPAECs were stretched to 12% ΔSA but then decreased when they were stretched to 37% ΔSA, similar to type I-like AECs. Perijunctional actin rings were observed in unstretched type I-like AECs treated with the Rho pathway inhibitor blebbistatin. Myosin phosphatase inhibition increased MLC2 phosphorylation in stretched type I-like AECs but had no effect on monolayer permeability. In summary, stretch alters RhoA activity, ROCK activity, and MLC2 phosphorylation in a manner dependent on stretch magnitude and cell type.
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Affiliation(s)
- Brian C DiPaolo
- Department of Bioengineering, University of Pennsylvania, 210 South 33rd St., Philadelphia, PA 19104-6321, USA
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Induction of cellular antioxidant defense by amifostine improves ventilator-induced lung injury. Crit Care Med 2012; 39:2711-21. [PMID: 21765345 DOI: 10.1097/ccm.0b013e3182284a5f] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
OBJECTIVES To test the hypothesis that preconditioning animals with amifostine improves ventilator-induced lung injury via induction of antioxidant defense enzymes. Mechanical ventilation at high tidal volume induces reactive oxygen species production and oxidative stress in the lung, which plays a major role in the pathogenesis of ventilator-induced lung injury. Amifostine attenuates oxidative stress and improves lipopolysaccharide-induced lung injury by acting as a direct scavenger of reactive oxygen and nitrogen species. This study tested effects of chronic amifostine administration on parameters of oxidative stress, lung barrier function, and inflammation associated with ventilator-induced lung injury. DESIGN Randomized and controlled laboratory investigation in mice and cell culture. SETTING University laboratory. SUBJECTS C57BL/6J mice. INTERVENTIONS Mice received once-daily dosing with amifostine (10-100 mg/kg, intraperitoneal injection) 3 days consecutively before high tidal volume ventilation (30 mL/kg, 4 hrs) at day 4. Pulmonary endothelial cell cultures were exposed to pathologic cyclic stretching (18% equibiaxial stretch) and thrombin in a previously verified two-hit model of in vitro ventilator-induced lung injury. MEASUREMENTS AND MAIN RESULTS Three-day amifostine preconditioning before high tidal volume attenuated high tidal volume-induced protein and cell accumulation in the alveolar space judged by bronchoalveolar lavage fluid analysis, decreased Evans Blue dye extravasation into the lung parenchyma, decreased biochemical parameters of high tidal volume-induced tissue oxidative stress, and inhibited high tidal volume-induced activation of redox-sensitive stress kinases and nuclear factor-kappa B inflammatory cascade. These protective effects of amifostine were associated with increased superoxide dismutase 2 expression and increased superoxide dismutase and catalase enzymatic activities in the animal and endothelial cell culture models of ventilator-induced lung injury. CONCLUSIONS Amifostine preconditioning activates lung tissue antioxidant cell defense mechanisms and may be a promising strategy for alleviation of ventilator-induced lung injury in critically ill patients subjected to extended mechanical ventilation.
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Makena PS, Gorantla VK, Ghosh MC, Bezawada L, Balazs L, Luellen C, Parthasarathi K, Waters CM, Sinclair SE. Lung injury caused by high tidal volume mechanical ventilation and hyperoxia is dependent on oxidant-mediated c-Jun NH2-terminal kinase activation. J Appl Physiol (1985) 2011; 111:1467-76. [PMID: 21799126 DOI: 10.1152/japplphysiol.00539.2011] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Both prolonged exposure to hyperoxia and large tidal volume mechanical ventilation can each independently cause lung injury. However, the combined impact of these insults is poorly understood. We recently reported that preexposure to hyperoxia for 12 h, followed by ventilation with large tidal volumes, induced significant lung injury and epithelial cell apoptosis compared with either stimulus alone (Makena et al. Am J Physiol Lung Cell Mol Physiol 299: L711-L719, 2010). The upstream mechanisms of this lung injury and apoptosis have not been clearly elucidated. We hypothesized that lung injury in this model was dependent on oxidative signaling via the c-Jun NH(2)-terminal kinases (JNK). We, therefore, evaluated lung injury and apoptosis in the presence of N-acetyl-cysteine (NAC) in both mouse and cell culture models, and we provide evidence that NAC significantly inhibited lung injury and apoptosis by reducing the production of ROS, activation of JNK, and apoptosis. To confirm JNK involvement in apoptosis, cells treated with a specific JNK inhibitor, SP600125, and subjected to preexposure to hyperoxia, followed by mechanical stretch, exhibited significantly reduced evidence of apoptosis. In conclusion, lung injury and apoptosis caused by preexposure to hyperoxia, followed by high tidal volume mechanical ventilation, induces ROS-mediated activation of JNK and mitochondrial-mediated apoptosis. NAC protects lung injury and apoptosis by inhibiting ROS-mediated activation of JNK and downstream proapoptotic signaling.
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Affiliation(s)
- Patrudu S Makena
- Dept. of Medicine, Univ. of Tennessee Health Science Center, Memphis, TN 38163, USA
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Crosby LM, Luellen C, Zhang Z, Tague LL, Sinclair SE, Waters CM. Balance of life and death in alveolar epithelial type II cells: proliferation, apoptosis, and the effects of cyclic stretch on wound healing. Am J Physiol Lung Cell Mol Physiol 2011; 301:L536-46. [PMID: 21724858 DOI: 10.1152/ajplung.00371.2010] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
After acute lung injury, repair of the alveolar epithelium occurs on a substrate undergoing cyclic mechanical deformation. While previous studies showed that mechanical stretch increased alveolar epithelial cell necrosis and apoptosis, the impact of cell death during repair was not determined. We examined epithelial repair during cyclic stretch (CS) in a scratch-wound model of primary rat alveolar type II (ATII) cells and found that CS altered the balance between proliferation and cell death. We measured cell migration, size, and density; intercellular gap formation; cell number, proliferation, and apoptosis; cytoskeletal organization; and focal adhesions in response to scratch wounding followed by CS for up to 24 h. Under static conditions, wounds were closed by 24 h, but repair was inhibited by CS. Wounding stimulated cell motility and proliferation, actin and vinculin redistribution, and focal adhesion formation at the wound edge, while CS impeded cell spreading, initiated apoptosis, stimulated cytoskeletal reorganization, and attenuated focal adhesion formation. CS also caused significant intercellular gap formation compared with static cells. Our results suggest that CS alters several mechanisms of epithelial repair and that an imbalance occurs between cell death and proliferation that must be overcome to restore the epithelial barrier.
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Affiliation(s)
- Lynn M Crosby
- Department of Physiology, University of Tennessee Health Science Center, Memphis, USA
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Birukova AA, Fu P, Xing J, Yakubov B, Cokic I, Birukov KG. Mechanotransduction by GEF-H1 as a novel mechanism of ventilator-induced vascular endothelial permeability. Am J Physiol Lung Cell Mol Physiol 2010; 298:L837-48. [PMID: 20348280 DOI: 10.1152/ajplung.00263.2009] [Citation(s) in RCA: 88] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Pathological lung overdistention associated with mechanical ventilation at high tidal volumes (ventilator-induced lung injury; VILI) compromises endothelial cell (EC) barrier leading to development of pulmonary edema and increased morbidity and mortality. We have previously shown involvement of microtubule (MT)-associated Rho-specific guanine nucleotide exchange factor GEF-H1 in the agonist-induced regulation of EC permeability. Using an in vitro model of human pulmonary EC exposed to VILI-relevant magnitude of cyclic stretch (18% CS) we tested a hypothesis that CS-induced alterations in MT dynamics contribute to the activation of Rho-dependent signaling via GEF-H1 and mediate early EC response to pathological mechanical stretch. Acute CS (30 min) induced disassembly of MT network, cell reorientation, and activation of Rho pathway, which was prevented by MT stabilizer taxol. siRNA-based GEF-H1 knockdown suppressed CS-induced disassembly of MT network, abolished Rho signaling, and attenuated CS-induced stress fiber formation and EC realignment compared with nonspecific RNA controls. Depletion of GEF-H1 in the murine two-hit model of VILI attenuated vascular leak induced by lung ventilation at high tidal volume and thrombin-derived peptide TRAP6. These data show for the first time the critical involvement of microtubules and microtubule-associated GEF-H1 in lung vascular endothelial barrier dysfunction induced by pathological mechanical strain.
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Affiliation(s)
- Anna A Birukova
- Section of Pulmonary and Critical Medicine, Department of Medicine, University of Chicago, Chicago, Illinois 60637, USA
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