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Lemmens-Gruber R, Tzotzos S. The Epithelial Sodium Channel-An Underestimated Drug Target. Int J Mol Sci 2023; 24:ijms24097775. [PMID: 37175488 PMCID: PMC10178586 DOI: 10.3390/ijms24097775] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Revised: 04/14/2023] [Accepted: 04/15/2023] [Indexed: 05/15/2023] Open
Abstract
Epithelial sodium channels (ENaC) are part of a complex network of interacting biochemical pathways and as such are involved in several disease states. Dependent on site and type of mutation, gain- or loss-of-function generated symptoms occur which span from asymptomatic to life-threatening disorders such as Liddle syndrome, cystic fibrosis or generalized pseudohypoaldosteronism type 1. Variants of ENaC which are implicated in disease assist further understanding of their molecular mechanisms in order to create models for specific pharmacological targeting. Identification and characterization of ENaC modifiers not only furthers our basic understanding of how these regulatory processes interact, but also enables discovery of new therapeutic targets for the disease conditions caused by ENaC dysfunction. Numerous test compounds have revealed encouraging results in vitro and in animal models but less in clinical settings. The EMA- and FDA-designated orphan drug solnatide is currently being tested in phase 2 clinical trials in the setting of acute respiratory distress syndrome, and the NOX1/ NOX4 inhibitor setanaxib is undergoing clinical phase 2 and 3 trials for therapy of primary biliary cholangitis, liver stiffness, and carcinoma. The established ENaC blocker amiloride is mainly used as an add-on drug in the therapy of resistant hypertension and is being studied in ongoing clinical phase 3 and 4 trials for special applications. This review focuses on discussing some recent developments in the search for novel therapeutic agents.
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Affiliation(s)
- Rosa Lemmens-Gruber
- Department of Pharmaceutical Sciences, Division of Pharmacology and Toxicology, University of Vienna, A-1090 Vienna, Austria
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2
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Mobley JA, Molyvdas A, Kojima K, Ahmad I, Jilling T, Li JL, Garantziotis S, Matalon S. The SARS-CoV-2 spike S1 protein induces global proteomic changes in ATII-like rat L2 cells that are attenuated by hyaluronan. Am J Physiol Lung Cell Mol Physiol 2023; 324:L413-L432. [PMID: 36719087 PMCID: PMC10042596 DOI: 10.1152/ajplung.00282.2022] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Revised: 12/29/2022] [Accepted: 01/25/2023] [Indexed: 02/01/2023] Open
Abstract
The COVID-19 pandemic continues to impose a major impact on global health and economy since its identification in early 2020, causing significant morbidity and mortality worldwide. Caused by the SARS-CoV-2 virus, along with a growing number of variants, COVID-19 has led to 651,918,402 confirmed cases and 6,656,601 deaths worldwide (as of December 27, 2022; https://covid19.who.int/). Despite advances in our understanding of COVID-19 pathogenesis, the precise mechanism by which SARS-CoV2 causes epithelial injury is incompletely understood. In this current study, robust application of global-discovery proteomics identified highly significant induced changes by the Spike S1 protein of SARS-CoV-2 in the proteome of alveolar type II (ATII)-like rat L2 cells that lack ACE2 receptors. Systems biology analysis revealed that the S1-induced proteomics changes were associated with three significant network hubs: E2F1, CREB1/RelA, and ROCK2/RhoA. We also found that pretreatment of L2 cells with high molecular weight hyaluronan (HMW-HA) greatly attenuated the S1 effects on the proteome. Western blotting analysis and cell cycle measurements confirmed the S1 upregulation of E2F1 and ROCK2/RhoA in L2 cells and the protective effects of HMW-HA. Taken as a whole, our studies revealed profound and novel biological changes that contribute to our current understanding of both S1 and hyaluronan biology. These data show that the S1 protein may contribute to epithelial injury induced by SARS-CoV-2. In addition, our work supports the potential benefit of HMW-HA in ameliorating SARS CoV-2-induced cell injury.
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Affiliation(s)
- James A Mobley
- Division of Molecular and Translational Biomedicine, Department of Anesthesiology and Perioperative Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States
- O'Neal Comprehensive Cancer Center, University of Alabama at Birmingham, Birmingham, Alabama, United States
| | - Adam Molyvdas
- Division of Molecular and Translational Biomedicine, Department of Anesthesiology and Perioperative Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States
| | - Kyoko Kojima
- O'Neal Comprehensive Cancer Center, University of Alabama at Birmingham, Birmingham, Alabama, United States
| | - Israr Ahmad
- Division of Molecular and Translational Biomedicine, Department of Anesthesiology and Perioperative Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States
| | - Tamas Jilling
- Division of Neonatology, Department of Pediatrics, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States
| | - Jian-Liang Li
- National Institute of Environmental Health Sciences, Durham, North Carolina, United States
| | - Stavros Garantziotis
- National Institute of Environmental Health Sciences, Durham, North Carolina, United States
| | - Sadis Matalon
- Division of Molecular and Translational Biomedicine, Department of Anesthesiology and Perioperative Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States
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3
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Lucas R, Hadizamani Y, Enkhbaatar P, Csanyi G, Caldwell RW, Hundsberger H, Sridhar S, Lever AA, Hudel M, Ash D, Ushio-Fukai M, Fukai T, Chakraborty T, Verin A, Eaton DC, Romero M, Hamacher J. Dichotomous Role of Tumor Necrosis Factor in Pulmonary Barrier Function and Alveolar Fluid Clearance. Front Physiol 2022; 12:793251. [PMID: 35264975 PMCID: PMC8899333 DOI: 10.3389/fphys.2021.793251] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Accepted: 11/30/2021] [Indexed: 02/04/2023] Open
Abstract
Alveolar-capillary leak is a hallmark of the acute respiratory distress syndrome (ARDS), a potentially lethal complication of severe sepsis, trauma and pneumonia, including COVID-19. Apart from barrier dysfunction, ARDS is characterized by hyper-inflammation and impaired alveolar fluid clearance (AFC), which foster the development of pulmonary permeability edema and hamper gas exchange. Tumor Necrosis Factor (TNF) is an evolutionarily conserved pleiotropic cytokine, involved in host immune defense against pathogens and cancer. TNF exists in both membrane-bound and soluble form and its mainly -but not exclusively- pro-inflammatory and cytolytic actions are mediated by partially overlapping TNFR1 and TNFR2 binding sites situated at the interface between neighboring subunits in the homo-trimer. Whereas TNFR1 signaling can mediate hyper-inflammation and impaired barrier function and AFC in the lungs, ligand stimulation of TNFR2 can protect from ventilation-induced lung injury. Spatially distinct from the TNFR binding sites, TNF harbors within its structure a lectin-like domain that rather protects lung function in ARDS. The lectin-like domain of TNF -mimicked by the 17 residue TIP peptide- represents a physiological mediator of alveolar-capillary barrier protection. and increases AFC in both hydrostatic and permeability pulmonary edema animal models. The TIP peptide directly activates the epithelial sodium channel (ENaC) -a key mediator of fluid and blood pressure control- upon binding to its α subunit, which is also a part of the non-selective cation channel (NSC). Activity of the lectin-like domain of TNF is preserved in complexes between TNF and its soluble TNFRs and can be physiologically relevant in pneumonia. Antibody- and soluble TNFR-based therapeutic strategies show considerable success in diseases such as rheumatoid arthritis, psoriasis and inflammatory bowel disease, but their chronic use can increase susceptibility to infection. Since the lectin-like domain of TNF does not interfere with TNF's anti-bacterial actions, while exerting protective actions in the alveolar-capillary compartments, it is currently evaluated in clinical trials in ARDS and COVID-19. A more comprehensive knowledge of the precise role of the TNFR binding sites versus the lectin-like domain of TNF in lung injury, tissue hypoxia, repair and remodeling may foster the development of novel therapeutics for ARDS.
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Affiliation(s)
- Rudolf Lucas
- Vascular Biology Center, Augusta University, Augusta, GA, United States,Department of Pharmacology and Toxicology, Augusta University, Augusta, GA, United States,Department of Medicine, Medical College of Georgia, Augusta University, Augusta, GA, United States,*Correspondence: Rudolf Lucas,
| | - Yalda Hadizamani
- Lungen-und Atmungsstiftung Bern, Bern, Switzerland,Pneumology, Clinic for General Internal Medicine, Lindenhofspital Bern, Bern, Switzerland
| | - Perenlei Enkhbaatar
- Department of Anesthesiology, University of Texas Medical Branch, Galveston, TX, United States
| | - Gabor Csanyi
- Vascular Biology Center, Augusta University, Augusta, GA, United States,Department of Pharmacology and Toxicology, Augusta University, Augusta, GA, United States
| | - Robert W. Caldwell
- Department of Pharmacology and Toxicology, Augusta University, Augusta, GA, United States
| | - Harald Hundsberger
- Department of Medical Biotechnology, University of Applied Sciences, Krems, Austria,Department of Dermatology, University Hospital of the Paracelsus Medical University, Salzburg, Austria
| | - Supriya Sridhar
- Vascular Biology Center, Augusta University, Augusta, GA, United States
| | - Alice Ann Lever
- Vascular Biology Center, Augusta University, Augusta, GA, United States,Department of Medicine, Medical College of Georgia, Augusta University, Augusta, GA, United States
| | - Martina Hudel
- Institute for Medical Microbiology, Justus-Liebig University, Giessen, Germany
| | - Dipankar Ash
- Vascular Biology Center, Augusta University, Augusta, GA, United States
| | - Masuko Ushio-Fukai
- Vascular Biology Center, Augusta University, Augusta, GA, United States,Department of Medicine, Medical College of Georgia, Augusta University, Augusta, GA, United States
| | - Tohru Fukai
- Vascular Biology Center, Augusta University, Augusta, GA, United States,Department of Pharmacology and Toxicology, Augusta University, Augusta, GA, United States,Charlie Norwood Veterans Affairs Medical Center, Augusta, GA, United States
| | - Trinad Chakraborty
- Institute for Medical Microbiology, Justus-Liebig University, Giessen, Germany
| | - Alexander Verin
- Vascular Biology Center, Augusta University, Augusta, GA, United States,Department of Medicine, Medical College of Georgia, Augusta University, Augusta, GA, United States
| | - Douglas C. Eaton
- Department of Medicine, School of Medicine, Emory University, Atlanta, GA, United States
| | - Maritza Romero
- Vascular Biology Center, Augusta University, Augusta, GA, United States,Department of Pharmacology and Toxicology, Augusta University, Augusta, GA, United States,Department of Anesthesiology and Perioperative Medicine, Medical College of Georgia, Augusta University, Augusta, GA, United States
| | - Jürg Hamacher
- Lungen-und Atmungsstiftung Bern, Bern, Switzerland,Pneumology, Clinic for General Internal Medicine, Lindenhofspital Bern, Bern, Switzerland,Medical Clinic V-Pneumology, Allergology, Intensive Care Medicine, and Environmental Medicine, Faculty of Medicine, University Medical Centre of the Saarland, Saarland University, Homburg, Germany,Institute for Clinical & Experimental Surgery, Faculty of Medicine, Saarland University, Homburg, Germany,Jürg Hamacher,
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Li X, Yu Y, Gorshkov B, Haigh S, Bordan Z, Weintraub D, Rudic RD, Chakraborty T, Barman SA, Verin AD, Su Y, Lucas R, Stepp DW, Chen F, Fulton DJR. Hsp70 Suppresses Mitochondrial Reactive Oxygen Species and Preserves Pulmonary Microvascular Barrier Integrity Following Exposure to Bacterial Toxins. Front Immunol 2018; 9:1309. [PMID: 29951058 PMCID: PMC6008539 DOI: 10.3389/fimmu.2018.01309] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Accepted: 05/25/2018] [Indexed: 01/22/2023] Open
Abstract
Pneumonia is a leading cause of death in children and the elderly worldwide, accounting for 15% of all deaths of children under 5 years old. Streptococcus pneumoniae is a common and aggressive cause of pneumonia and can also contribute to meningitis and sepsis. Despite the widespread use of antibiotics, mortality rates for pneumonia remain unacceptably high in part due to the release of bacterial toxins. Pneumolysin (PLY) is a cholesterol-dependent toxin that is produced by Streptococcus, and it is both necessary and sufficient for the development of the extensive pulmonary permeability edema that underlies acute lung injury. The mechanisms by which PLY disrupts the pulmonary endothelial barrier are not fully understood. Previously, we found that reactive oxygen species (ROS) contribute to the barrier destructive effects of PLY and identified an unexpected but potent role of Hsp70 in suppressing ROS production. The ability of Hsp70 to influence PLY-induced barrier dysfunction is not yet described, and the goal of the current study was to identify whether Hsp70 upregulation is an effective strategy to protect the lung microvascular endothelial barrier from G+ bacterial toxins. Overexpression of Hsp70 via adenovirus-mediated gene transfer attenuated PLY-induced increases in permeability in human lung microvascular endothelial cells (HLMVEC) with no evidence of cytotoxicity. To adopt a more translational approach, we employed a pharmacological approach using geranylgeranylacetone (GGA) to acutely upregulate endogenous Hsp70 expression. Following acute treatment (6 h) with GGA, HLMVECs exposed to PLY displayed improved cell viability and enhanced endothelial barrier function as measured by both Electric Cell-substrate Impedance Sensing (ECIS) and transwell permeability assays compared to control treated cells. PLY promoted increased mitochondrial ROS, decreased mitochondrial oxygen consumption, and increased caspase 3 cleavage and cell death, which were collectively improved in cells pretreated with GGA. In mice, IP pretreatment with GGA 24 h prior to IT administration of PLY resulted in significantly less Evans Blue Dye extravasation compared to vehicle, indicating preserved endothelial barrier integrity and suggesting that the acute upregulation of Hsp70 may be an effective therapeutic approach in the treatment of lung injury associated with pneumonia.
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Affiliation(s)
- Xueyi Li
- Vascular Biology Center, Medical College of Georgia at Augusta University, Augusta, Georgia
| | - Yanfang Yu
- Vascular Biology Center, Medical College of Georgia at Augusta University, Augusta, Georgia.,Department of Forensic Medicine, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Boris Gorshkov
- Vascular Biology Center, Medical College of Georgia at Augusta University, Augusta, Georgia
| | - Stephen Haigh
- Vascular Biology Center, Medical College of Georgia at Augusta University, Augusta, Georgia
| | - Zsuzsanna Bordan
- Vascular Biology Center, Medical College of Georgia at Augusta University, Augusta, Georgia
| | - Daniel Weintraub
- Vascular Biology Center, Medical College of Georgia at Augusta University, Augusta, Georgia
| | - Radu Daniel Rudic
- Department of Pharmacology and Toxicology, Medical College of Georgia at Augusta University, Augusta, GA, United States
| | - Trinad Chakraborty
- Institute for Medical Microbiology, Justus-Liebig University Giessen, Giessen, Germany
| | - Scott A Barman
- Department of Pharmacology and Toxicology, Medical College of Georgia at Augusta University, Augusta, GA, United States
| | - Alexander D Verin
- Vascular Biology Center, Medical College of Georgia at Augusta University, Augusta, Georgia
| | - Yunchao Su
- Department of Pharmacology and Toxicology, Medical College of Georgia at Augusta University, Augusta, GA, United States
| | - Rudolf Lucas
- Vascular Biology Center, Medical College of Georgia at Augusta University, Augusta, Georgia.,Department of Pharmacology and Toxicology, Medical College of Georgia at Augusta University, Augusta, GA, United States
| | - David W Stepp
- Department of Pharmacology and Toxicology, Medical College of Georgia at Augusta University, Augusta, GA, United States
| | - Feng Chen
- Vascular Biology Center, Medical College of Georgia at Augusta University, Augusta, Georgia.,Department of Forensic Medicine, Nanjing Medical University, Nanjing, Jiangsu, China
| | - David J R Fulton
- Vascular Biology Center, Medical College of Georgia at Augusta University, Augusta, Georgia.,Department of Pharmacology and Toxicology, Medical College of Georgia at Augusta University, Augusta, GA, United States
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5
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Yang G, Pillich H, White R, Czikora I, Pochic I, Yue Q, Hudel M, Gorshkov B, Verin A, Sridhar S, Isales CM, Eaton DC, Hamacher J, Chakraborty T, Lucas R. Listeriolysin O Causes ENaC Dysfunction in Human Airway Epithelial Cells. Toxins (Basel) 2018; 10:toxins10020079. [PMID: 29439494 PMCID: PMC5848180 DOI: 10.3390/toxins10020079] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Revised: 02/01/2018] [Accepted: 02/07/2018] [Indexed: 01/22/2023] Open
Abstract
Pulmonary permeability edema is characterized by reduced alveolar Na⁺ uptake capacity and capillary barrier dysfunction and is a potentially lethal complication of listeriosis. Apical Na⁺ uptake is mainly mediated by the epithelial sodium channel (ENaC) and initiates alveolar liquid clearance. Here we examine how listeriolysin O (LLO), the pore-forming toxin of Listeria monocytogenes, impairs the expression and activity of ENaC. To that purpose, we studied how sub-lytic concentrations of LLO affect negative and positive regulators of ENaC expression in the H441 airway epithelial cell line. LLO reduced expression of the crucial ENaC-α subunit in H441 cells within 2 h and this was preceded by activation of PKC-α, a negative regulator of the channel's expression. At later time points, LLO caused a significant reduction in the phosphorylation of Sgk-1 at residue T256 and of Akt-1 at residue S473, both of which are required for full activation of ENaC. The TNF-derived TIP peptide prevented LLO-mediated PKC-α activation and restored phospho-Sgk-1-T256. The TIP peptide also counteracted the observed LLO-induced decrease in amiloride-sensitive Na⁺ current and ENaC-α expression in H441 cells. Intratracheally instilled LLO caused profound pulmonary edema formation in mice, an effect that was prevented by the TIP peptide; thus indicating the therapeutic potential of the peptide for the treatment of pore-forming toxin-associated permeability edema.
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Affiliation(s)
- Guang Yang
- Vascular Biology Center, Medical College of Georgia at Augusta University, Room CB-3213B, Augusta, GA 30912-2500, USA.
| | - Helena Pillich
- Institute of Medical Microbiology, Justus-Liebig University Giessen, 35392 Gießen, Germany.
| | - Richard White
- Department of Pharmacology and Toxicology, Medical College of Georgia at Augusta University, Room CB-3213B, Augusta, GA 30912-2500, USA.
- Department of Biomedical Sciences, Georgia Campus-Philadelphia College of Osteopathic Medicine, Atlanta, GA 30224, USA.
| | - Istvan Czikora
- Vascular Biology Center, Medical College of Georgia at Augusta University, Room CB-3213B, Augusta, GA 30912-2500, USA.
| | - Isabelle Pochic
- Biochemical Pharmacology, University of Konstanz, 78464 Konstanz, Germany.
- Sandoz Inc., 83607 Holzkirchen, Germany.
| | - Qiang Yue
- Department of Physiology, Emory School of Medicine, Atlanta, GA 30307, USA.
| | - Martina Hudel
- Institute of Medical Microbiology, Justus-Liebig University Giessen, 35392 Gießen, Germany.
| | - Boris Gorshkov
- Vascular Biology Center, Medical College of Georgia at Augusta University, Room CB-3213B, Augusta, GA 30912-2500, USA.
| | - Alexander Verin
- Vascular Biology Center, Medical College of Georgia at Augusta University, Room CB-3213B, Augusta, GA 30912-2500, USA.
| | - Supriya Sridhar
- Vascular Biology Center, Medical College of Georgia at Augusta University, Room CB-3213B, Augusta, GA 30912-2500, USA.
| | - Carlos M Isales
- Department of Medicine, Medical College of Georgia, Augusta, GA 30901, USA.
| | - Douglas C Eaton
- Department of Physiology, Emory School of Medicine, Atlanta, GA 30307, USA.
| | - Jürg Hamacher
- Biochemical Pharmacology, University of Konstanz, 78464 Konstanz, Germany.
- Department of Pneumology, Lindenhofspital, 3001 Bern, Switzerland.
- Internal, Pulmonary and Critical Care Medicine, Saarland University, 66424 Homburg/Saar, Germany.
- Lungen-und Atmungsstifung, 3001 Bern, Switzerland.
| | - Trinad Chakraborty
- Institute of Medical Microbiology, Justus-Liebig University Giessen, 35392 Gießen, Germany.
| | - Rudolf Lucas
- Vascular Biology Center, Medical College of Georgia at Augusta University, Room CB-3213B, Augusta, GA 30912-2500, USA.
- Department of Pharmacology and Toxicology, Medical College of Georgia at Augusta University, Room CB-3213B, Augusta, GA 30912-2500, USA.
- Department of Medicine, Medical College of Georgia, Augusta, GA 30901, USA.
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Hamacher J, Hadizamani Y, Borgmann M, Mohaupt M, Männel DN, Moehrlen U, Lucas R, Stammberger U. Cytokine-Ion Channel Interactions in Pulmonary Inflammation. Front Immunol 2018; 8:1644. [PMID: 29354115 PMCID: PMC5758508 DOI: 10.3389/fimmu.2017.01644] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Accepted: 11/10/2017] [Indexed: 12/12/2022] Open
Abstract
The lungs conceptually represent a sponge that is interposed in series in the bodies’ systemic circulation to take up oxygen and eliminate carbon dioxide. As such, it matches the huge surface areas of the alveolar epithelium to the pulmonary blood capillaries. The lung’s constant exposure to the exterior necessitates a competent immune system, as evidenced by the association of clinical immunodeficiencies with pulmonary infections. From the in utero to the postnatal and adult situation, there is an inherent vital need to manage alveolar fluid reabsorption, be it postnatally, or in case of hydrostatic or permeability edema. Whereas a wealth of literature exists on the physiological basis of fluid and solute reabsorption by ion channels and water pores, only sparse knowledge is available so far on pathological situations, such as in microbial infection, acute lung injury or acute respiratory distress syndrome, and in the pulmonary reimplantation response in transplanted lungs. The aim of this review is to discuss alveolar liquid clearance in a selection of lung injury models, thereby especially focusing on cytokines and mediators that modulate ion channels. Inflammation is characterized by complex and probably time-dependent co-signaling, interactions between the involved cell types, as well as by cell demise and barrier dysfunction, which may not uniquely determine a clinical picture. This review, therefore, aims to give integrative thoughts and wants to foster the unraveling of unmet needs in future research.
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Affiliation(s)
- Jürg Hamacher
- Internal Medicine and Pneumology, Lindenhofspital, Bern, Switzerland.,Internal Medicine V - Pneumology, Allergology, Respiratory and Environmental Medicine, Faculty of Medicine, Saarland University, Saarbrücken, Germany.,Lungen- und Atmungsstiftung Bern, Bern, Switzerland
| | - Yalda Hadizamani
- Internal Medicine and Pneumology, Lindenhofspital, Bern, Switzerland.,Lungen- und Atmungsstiftung Bern, Bern, Switzerland
| | - Michèle Borgmann
- Internal Medicine and Pneumology, Lindenhofspital, Bern, Switzerland.,Lungen- und Atmungsstiftung Bern, Bern, Switzerland
| | - Markus Mohaupt
- Internal Medicine, Sonnenhofspital Bern, Bern, Switzerland
| | | | - Ueli Moehrlen
- Paediatric Visceral Surgery, Universitäts-Kinderspital Zürich, Zürich, Switzerland
| | - Rudolf Lucas
- Department of Pharmacology and Toxicology, Vascular Biology Center, Medical College of Georgia, Augusta, GA, United States
| | - Uz Stammberger
- Lungen- und Atmungsstiftung Bern, Bern, Switzerland.,Novartis Institutes for Biomedical Research, Translational Clinical Oncology, Novartis Pharma AG, Basel, Switzerland
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Krenn K, Lucas R, Croizé A, Boehme S, Klein KU, Hermann R, Markstaller K, Ullrich R. Inhaled AP301 for treatment of pulmonary edema in mechanically ventilated patients with acute respiratory distress syndrome: a phase IIa randomized placebo-controlled trial. CRITICAL CARE : THE OFFICIAL JOURNAL OF THE CRITICAL CARE FORUM 2017; 21:194. [PMID: 28750677 PMCID: PMC5531100 DOI: 10.1186/s13054-017-1795-x] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/29/2017] [Accepted: 07/12/2017] [Indexed: 02/08/2023]
Abstract
Background High-permeability pulmonary edema is a hallmark of acute respiratory distress syndrome (ARDS) and is frequently accompanied by impaired alveolar fluid clearance (AFC). AP301 enhances AFC by activating epithelial sodium channels (ENaCs) on alveolar epithelial cells, and we investigated its effect on extravascular lung water index (EVLWI) in mechanically ventilated patients with ARDS. Methods Forty adult mechanically ventilated patients with ARDS were included in a randomized, double-blind, placebo-controlled trial for proof of concept. Patients were treated with inhaled AP301 (n = 20) or placebo (0.9% NaCl; n = 20) twice daily for 7 days. EVLWI was measured by thermodilution (PiCCO®), and treatment groups were compared using the nonparametric Mann–Whitney U test. Results AP301 inhalation was well tolerated. No differences in mean baseline-adjusted change in EVLWI from screening to day 7 were found between the AP301 and placebo group (p = 0.196). There was no difference in the PaO2/FiO2 ratio, ventilation pressures, Murray lung injury score, or 28-day mortality between the treatment groups. An exploratory subgroup analysis according to severity of illness showed reductions in EVLWI (p = 0.04) and ventilation pressures (p < 0.05) over 7 days in patients with initial sequential organ failure assessment (SOFA) scores ≥11 inhaling AP301 versus placebo, but not in patients with SOFA scores ≤10. Conclusions There was no difference in mean baseline-adjusted EVLWI between the AP301 and placebo group. An exploratory post-hoc subgroup analysis indicated reduced EVLWI in patients with SOFA scores ≥11 receiving AP301. These results suggest further confirmation in future clinical trials of inhaled AP301 for treatment of pulmonary edema in patients with ARDS. Trial registration The study was prospectively registered at clinicaltrials.gov, NCT01627613. Registered 20 June 2012. Electronic supplementary material The online version of this article (doi:10.1186/s13054-017-1795-x) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Katharina Krenn
- Department of Anaesthesia, Critical Care and Pain Medicine, Medical University of Vienna, Waehringer Guertel 18-20, A-1090, Vienna, Austria
| | - Rudolf Lucas
- Vascular Biology Center, Department of Pharmacology and Toxicology and Division of Pulmonary and Critical Care Medicine, Medical College of Georgia, Augusta University, Augusta, GA, USA
| | - Adrien Croizé
- Department of Anaesthesia, Critical Care and Pain Medicine, Medical University of Vienna, Waehringer Guertel 18-20, A-1090, Vienna, Austria
| | - Stefan Boehme
- Department of Anaesthesia, Critical Care and Pain Medicine, Medical University of Vienna, Waehringer Guertel 18-20, A-1090, Vienna, Austria
| | - Klaus Ulrich Klein
- Department of Anaesthesia, Critical Care and Pain Medicine, Medical University of Vienna, Waehringer Guertel 18-20, A-1090, Vienna, Austria
| | | | - Klaus Markstaller
- Department of Anaesthesia, Critical Care and Pain Medicine, Medical University of Vienna, Waehringer Guertel 18-20, A-1090, Vienna, Austria
| | - Roman Ullrich
- Department of Anaesthesia, Critical Care and Pain Medicine, Medical University of Vienna, Waehringer Guertel 18-20, A-1090, Vienna, Austria.
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8
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Czikora I, Alli AA, Sridhar S, Matthay MA, Pillich H, Hudel M, Berisha B, Gorshkov B, Romero MJ, Gonzales J, Wu G, Huo Y, Su Y, Verin AD, Fulton D, Chakraborty T, Eaton DC, Lucas R. Epithelial Sodium Channel-α Mediates the Protective Effect of the TNF-Derived TIP Peptide in Pneumolysin-Induced Endothelial Barrier Dysfunction. Front Immunol 2017; 8:842. [PMID: 28785264 PMCID: PMC5519615 DOI: 10.3389/fimmu.2017.00842] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2017] [Accepted: 07/04/2017] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Streptococcus pneumoniae is a major etiologic agent of bacterial pneumonia. Autolysis and antibiotic-mediated lysis of pneumococci induce release of the pore-forming toxin, pneumolysin (PLY), their major virulence factor, which is a prominent cause of acute lung injury. PLY inhibits alveolar liquid clearance and severely compromises alveolar-capillary barrier function, leading to permeability edema associated with pneumonia. As a consequence, alveolar flooding occurs, which can precipitate lethal hypoxemia by impairing gas exchange. The α subunit of the epithelial sodium channel (ENaC) is crucial for promoting Na+ reabsorption across Na+-transporting epithelia. However, it is not known if human lung microvascular endothelial cells (HL-MVEC) also express ENaC-α and whether this subunit is involved in the regulation of their barrier function. METHODS The presence of α, β, and γ subunits of ENaC and protein phosphorylation status in HL-MVEC were assessed in western blotting. The role of ENaC-α in monolayer resistance of HL-MVEC was examined by depletion of this subunit by specific siRNA and by employing the TNF-derived TIP peptide, a specific activator that directly binds to ENaC-α. RESULTS HL-MVEC express all three subunits of ENaC, as well as acid-sensing ion channel 1a (ASIC1a), which has the capacity to form hybrid non-selective cation channels with ENaC-α. Both TIP peptide, which specifically binds to ENaC-α, and the specific ASIC1a activator MitTx significantly strengthened barrier function in PLY-treated HL-MVEC. ENaC-α depletion significantly increased sensitivity to PLY-induced hyperpermeability and in addition, blunted the protective effect of both the TIP peptide and MitTx, indicating an important role for ENaC-α and for hybrid NSC channels in barrier function of HL-MVEC. TIP peptide blunted PLY-induced phosphorylation of both calmodulin-dependent kinase II (CaMKII) and of its substrate, the actin-binding protein filamin A (FLN-A), requiring the expression of both ENaC-α and ASIC1a. Since non-phosphorylated FLN-A promotes ENaC channel open probability and blunts stress fiber formation, modulation of this activity represents an attractive target for the protective actions of ENaC-α in both barrier function and liquid clearance. CONCLUSION Our results in cultured endothelial cells demonstrate a previously unrecognized role for ENaC-α in strengthening capillary barrier function that may apply to the human lung. Strategies aiming to activate endothelial NSC channels that contain ENaC-α should be further investigated as a novel approach to improve barrier function in the capillary endothelium during pneumonia.
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Affiliation(s)
- Istvan Czikora
- Vascular Biology Center, Medical College of Georgia, Augusta University, Augusta, GA, United States
| | - Abdel A Alli
- Department of Physiology and Functional Genomics, University of Florida College of Medicine, Gainesville, FL, United States.,Division of Nephrology, Hypertension, and Renal Transplantation, Department of Medicine, University of Florida College of Medicine, Gainesville, FL, United States
| | - Supriya Sridhar
- Vascular Biology Center, Medical College of Georgia, Augusta University, Augusta, GA, United States
| | - Michael A Matthay
- Cardiovascular Research Institute, UCSF, San Francisco, CA, United States
| | - Helena Pillich
- Institute for Medical Microbiology, Justus-Liebig University, Giessen, Germany
| | - Martina Hudel
- Institute for Medical Microbiology, Justus-Liebig University, Giessen, Germany
| | - Besim Berisha
- Institute for Medical Microbiology, Justus-Liebig University, Giessen, Germany
| | - Boris Gorshkov
- Vascular Biology Center, Medical College of Georgia, Augusta University, Augusta, GA, United States
| | - Maritza J Romero
- Vascular Biology Center, Medical College of Georgia, Augusta University, Augusta, GA, United States.,Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, GA, United States
| | - Joyce Gonzales
- Department of Medicine, Medical College of Georgia, Augusta University, Augusta, GA, United States
| | - Guangyu Wu
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, GA, United States
| | - Yuqing Huo
- Vascular Biology Center, Medical College of Georgia, Augusta University, Augusta, GA, United States.,Department of Medicine, Medical College of Georgia, Augusta University, Augusta, GA, United States
| | - Yunchao Su
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, GA, United States
| | - Alexander D Verin
- Vascular Biology Center, Medical College of Georgia, Augusta University, Augusta, GA, United States.,Department of Medicine, Medical College of Georgia, Augusta University, Augusta, GA, United States
| | - David Fulton
- Vascular Biology Center, Medical College of Georgia, Augusta University, Augusta, GA, United States.,Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, GA, United States
| | - Trinad Chakraborty
- Institute for Medical Microbiology, Justus-Liebig University, Giessen, Germany
| | - Douglas C Eaton
- Department of Physiology, Emory University School of Medicine, Atlanta, GA, United States
| | - Rudolf Lucas
- Vascular Biology Center, Medical College of Georgia, Augusta University, Augusta, GA, United States.,Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, GA, United States.,Department of Medicine, Medical College of Georgia, Augusta University, Augusta, GA, United States
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9
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Willam A, Aufy M, Tzotzos S, El-Malazi D, Poser F, Wagner A, Unterköfler B, Gurmani D, Martan D, Iqbal SM, Fischer B, Fischer H, Pietschmann H, Czikora I, Lucas R, Lemmens-Gruber R, Shabbir W. TNF Lectin-Like Domain Restores Epithelial Sodium Channel Function in Frameshift Mutants Associated with Pseudohypoaldosteronism Type 1B. Front Immunol 2017; 8:601. [PMID: 28611771 PMCID: PMC5447021 DOI: 10.3389/fimmu.2017.00601] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Accepted: 05/08/2017] [Indexed: 11/28/2022] Open
Abstract
Previous in vitro studies have indicated that tumor necrosis factor (TNF) activates amiloride-sensitive epithelial sodium channel (ENaC) current through its lectin-like (TIP) domain, since cyclic peptides mimicking the TIP domain (e.g., solnatide), showed ENaC-activating properties. In the current study, the effects of TNF and solnatide on individual ENaC subunits or ENaC carrying mutated glycosylation sites in the α-ENaC subunit were compared, revealing a similar mode of action for TNF and solnatide and corroborating the previous assumption that the lectin-like domain of TNF is the relevant molecular structure for ENaC activation. Accordingly, TNF enhanced ENaC current by increasing open probability of the glycosylated channel, position N511 in the α-ENaC subunit being identified as the most important glycosylation site. TNF significantly increased Na+ current through ENaC comprising only the pore forming subunits α or δ, was less active in ENaC comprising only β-subunits, and showed no effect on ENaC comprising γ-subunits. TNF did not increase the membrane abundance of ENaC subunits to the extent observed with solnatide. Since the α-subunit is believed to play a prominent role in the ENaC current activating effect of TNF and TIP, we investigated whether TNF and solnatide can enhance αβγ-ENaC current in α-ENaC loss-of-function frameshift mutants. The efficacy of solnatide has been already proven in pathological conditions involving ENaC in phase II clinical trials. The frameshift mutations αI68fs, αT169fs, αP197fs, αE272fs, αF435fs, αR438fs, αY447fs, αR448fs, αS452fs, and αT482fs have been reported to cause pseudohypoaldosteronism type 1B (PHA1B), a rare, life-threatening, salt-wasting disease, which hitherto has been treated only symptomatically. In a heterologous expression system, all frameshift mutants showed significantly reduced amiloride-sensitive whole-cell current compared to wild type αβγ-ENaC, whereas membrane abundance varied between mutants. Solnatide restored function in α-ENaC frameshift mutants to current density levels of wild type ENaC or higher despite their lacking a binding site for solnatide, previously located to the region between TM2 and the C-terminus of the α-subunit. TNF similarly restored current density to wild type levels in the mutant αR448fs. Activation of βγ-ENaC may contribute to this moderate current enhancement, but whatever the mechanism, experimental data indicate that solnatide could be a new strategy to treat PHA1B.
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Affiliation(s)
- Anita Willam
- Department of Pharmacology and Toxicology, University of Vienna, Vienna, Austria.,APEPTICO GmbH, Vienna, Austria
| | - Mohammed Aufy
- Department of Pharmacology and Toxicology, University of Vienna, Vienna, Austria
| | | | - Dina El-Malazi
- Department of Pharmacology and Toxicology, University of Vienna, Vienna, Austria
| | - Franziska Poser
- Department of Pharmacology and Toxicology, University of Vienna, Vienna, Austria
| | - Alina Wagner
- Department of Pharmacology and Toxicology, University of Vienna, Vienna, Austria
| | - Birgit Unterköfler
- Department of Pharmacology and Toxicology, University of Vienna, Vienna, Austria
| | - Didja Gurmani
- Department of Pharmacology and Toxicology, University of Vienna, Vienna, Austria
| | - David Martan
- Department of Pharmacology and Toxicology, University of Vienna, Vienna, Austria
| | | | | | | | | | - Istvan Czikora
- Vascular Biology Center, Medical College of Georgia, Augusta University, Augusta, GA, United States
| | - Rudolf Lucas
- Vascular Biology Center, Medical College of Georgia, Augusta University, Augusta, GA, United States
| | - Rosa Lemmens-Gruber
- Department of Pharmacology and Toxicology, University of Vienna, Vienna, Austria
| | - Waheed Shabbir
- Department of Pharmacology and Toxicology, University of Vienna, Vienna, Austria.,APEPTICO GmbH, Vienna, Austria
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10
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Maurer J, Hupp S, Bischoff C, Foertsch C, Mitchell TJ, Chakraborty T, Iliev AI. Distinct Neurotoxicity Profile of Listeriolysin O from Listeria monocytogenes. Toxins (Basel) 2017; 9:toxins9010034. [PMID: 28098781 PMCID: PMC5308266 DOI: 10.3390/toxins9010034] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Revised: 01/09/2017] [Accepted: 01/10/2017] [Indexed: 11/16/2022] Open
Abstract
Cholesterol-dependent cytolysins (CDCs) are protein toxins that originate from Gram-positive bacteria and contribute substantially to their pathogenicity. CDCs bind membrane cholesterol and build prepores and lytic pores. Some effects of the toxins are observed in non-lytic concentrations. Two pathogens, Streptococcus pneumoniae and Listeria monocytogenes, cause fatal bacterial meningitis, and both produce toxins of the CDC family-pneumolysin and listeriolysin O, respectively. It has been demonstrated that pneumolysin produces dendritic varicosities (dendrite swellings) and dendritic spine collapse in the mouse neocortex, followed by synaptic loss and astrocyte cell shape remodeling without elevated cell death. We utilized primary glial cultures and acute mouse brain slices to examine the neuropathological effects of listeriolysin O and to compare it to pneumolysin with identical hemolytic activity. In cultures, listeriolysin O permeabilized cells slower than pneumolysin did but still initiated non-lytic astrocytic cell shape changes, just as pneumolysin did. In an acute brain slice culture system, listeriolysin O produced dendritic varicosities in an NMDA-dependent manner but failed to cause dendritic spine collapse and cortical astrocyte reorganization. Thus, listeriolysin O demonstrated slower cell permeabilization and milder glial cell remodeling ability than did pneumolysin and lacked dendritic spine collapse capacity but exhibited equivalent dendritic pathology.
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Affiliation(s)
- Jana Maurer
- DFG Membrane/Cytoskeleton Interaction Group, Institute of Pharmacology and Toxicology & Rudolf Virchow Center for Experimental Biomedical Science, University of Würzburg, Versbacherstr. 9, 97078 Würzburg, Germany.
- Institute of Physiology and Pathophysiology, Heidelberg University, Im Neuenheimer Feld 326, 69120 Heidelberg, Germany.
| | - Sabrina Hupp
- DFG Membrane/Cytoskeleton Interaction Group, Institute of Pharmacology and Toxicology & Rudolf Virchow Center for Experimental Biomedical Science, University of Würzburg, Versbacherstr. 9, 97078 Würzburg, Germany.
- Institute of Anatomy, University of Bern, Baltzerstrasse 2, 3012 Bern, Switzerland.
| | - Carolin Bischoff
- DFG Membrane/Cytoskeleton Interaction Group, Institute of Pharmacology and Toxicology & Rudolf Virchow Center for Experimental Biomedical Science, University of Würzburg, Versbacherstr. 9, 97078 Würzburg, Germany.
| | - Christina Foertsch
- DFG Membrane/Cytoskeleton Interaction Group, Institute of Pharmacology and Toxicology & Rudolf Virchow Center for Experimental Biomedical Science, University of Würzburg, Versbacherstr. 9, 97078 Würzburg, Germany.
| | - Timothy J Mitchell
- Chair of Microbial Infection and Immunity, Institute of Microbiology and Infection, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK.
| | - Trinad Chakraborty
- Institute for Medical Microbiology, University of Giessen, Schubertstr. 81, 35392 Giessen, Germany.
| | - Asparouh I Iliev
- DFG Membrane/Cytoskeleton Interaction Group, Institute of Pharmacology and Toxicology & Rudolf Virchow Center for Experimental Biomedical Science, University of Würzburg, Versbacherstr. 9, 97078 Würzburg, Germany.
- Institute of Anatomy, University of Bern, Baltzerstrasse 2, 3012 Bern, Switzerland.
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11
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RhoA S-nitrosylation as a regulatory mechanism influencing endothelial barrier function in response to G +-bacterial toxins. Biochem Pharmacol 2016; 127:34-45. [PMID: 28017778 DOI: 10.1016/j.bcp.2016.12.014] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2016] [Accepted: 12/19/2016] [Indexed: 01/05/2023]
Abstract
Disruption of the endothelial barrier in response to Gram positive (G+) bacterial toxins is a major complication of acute lung injury (ALI) and can be further aggravated by antibiotics which stimulate toxin release. The integrity of the pulmonary endothelial barrier is mediated by the balance of disruptive forces such as the small GTPase RhoA, and protective forces including endothelium-derived nitric oxide (NO). How NO protects against the barrier dysfunction is incompletely understood and our goal was to determine whether NO and S-nitrosylation can modulate RhoA activity and whether this mechanism is important for G+ toxin-induced microvascular permeability. We found that the G+ toxin listeriolysin-O (LLO) increased RhoA activity and that NO and S-NO donors inhibit RhoA activity. RhoA was robustly S-nitrosylated as determined by biotin-switch and mercury column analysis. MS revealed that three primary cysteine residues are S-nitrosylated including cys16, cys20 and cys159. Mutation of these residues to serine diminished S-nitrosylation to endogenous NO and mutant RhoA was less sensitive to inhibition by S-NO. G+-toxins stimulated the denitrosylation of RhoA which was not mediated by S-nitrosoglutathione reductase (GSNOR), thioredoxin (TRX) or thiol-dependent enzyme activity but was instead stimulated directly by elevated calcium levels. Calcium-promoted the direct denitrosylation of WT but not mutant RhoA and mutant RhoA adenovirus was more effective than WT in disrupting the barrier integrity of human lung microvascular endothelial cells. In conclusion, we reveal a novel mechanism by which NO and S-nitrosylation reduces RhoA activity which may be of significance in the management of pulmonary endothelial permeability induced by G+-toxins.
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12
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Vibrio vulnificus VvhA induces NF-κB-dependent mitochondrial cell death via lipid raft-mediated ROS production in intestinal epithelial cells. Cell Death Dis 2015; 6:1655. [PMID: 25695598 PMCID: PMC4669806 DOI: 10.1038/cddis.2015.19] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2014] [Revised: 01/07/2015] [Accepted: 01/07/2015] [Indexed: 01/29/2023]
Abstract
The Gram-negative bacterium Vibrio vulnificus produces hemolysin (VvhA), which induces cytotoxicity in mammalian cells. However, our understanding of the cytotoxic mechanism and the modes of action of VvhA are still fragmentary and incomplete. The recombinant protein (r) VvhA (50 pg/ml) significantly induces necrotic cell death and apoptosis in human intestinal epithelial (INT-407) cells. The apoptotic cell death induced by rVvhA is highly susceptible to the sequestration of cholesterol by methyl-β-cyclodextrin, whereas for necrotic cell death, this shows a marginal effect. We found that rVvhA induces the aggregation of lipid raft components coupled with NADPH oxidase enzymes, in which rVvhA increased the interaction of NADPH oxidase 2 (NOX2, gp91phox) with a cytosolic protein NCF1 (p47phox) to facilitate the production of reactive oxygen species (ROS). rVvhA uniquely stimulated a conventional PKC isoform PKCα and induced the phosphorylation of both ERK and JNK, which are responsible for the activation of transcription factor NF-κB. rVvhA induced an NF-κB-dependent imbalance of the Bcl-2/Bax ratio, the release of mitochondrial cytochrome c, and caspase-3/-9 activation during its promotion of apoptotic cell death. In addition, rVvhA has the ability to inhibit the expression of cell cycle-related proteins, such as CDK2, CDK4, cyclin D1, and cyclin E. These results demonstrate that rVvhA induces NF-κB-dependent mitochondrial cell death via lipid raft-mediated ROS production by the distinct activation of PKCα and ERK/JNK in intestinal epithelial cells.
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13
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Hartmann EK, Ziebart A, Thomas R, Liu T, Schad A, Tews M, Moosmann B, Kamuf J, Duenges B, Thal SC, David M. Inhalation therapy with the synthetic TIP-like peptide AP318 attenuates pulmonary inflammation in a porcine sepsis model. BMC Pulm Med 2015; 15:7. [PMID: 25879802 PMCID: PMC4346123 DOI: 10.1186/s12890-015-0002-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2014] [Accepted: 01/19/2015] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND The lectin-like domain of TNF-α can be mimicked by synthetic TIP peptides and represents an innovative pharmacologic option to treat edematous respiratory failure. TIP inhalation was shown to reduce pulmonary edema and improve gas exchange. In addition to its edema resolution effect, TIP peptides may exert some anti-inflammatory properties. The present study therefore investigates the influence of the inhaled TIP peptide AP318 on intrapulmonary inflammatory response in a porcine model of systemic sepsis. METHODS In a randomized-blinded setting lung injury was induced in 18 pigs by lipopolysaccharide-infusion and a second hit with a short period of ventilator-induced lung stress, followed by a six-hour observation period. The animals received either two inhalations with the peptide (AP318, 2×1 mg kg(-1)) or vehicle. Post-mortem pulmonary expression of inflammatory and mechanotransduction markers were determined by real-time polymerase chain reaction (IL-1β, IL-6, TNF-α, COX-2, iNOS, amphiregulin, and tenascin-c). Furthermore, regional histopathological lung injury, edema formation and systemic inflammation were quantified. RESULTS Despite similar systemic response to lipopolysaccharide infusion in both groups, pulmonary inflammation (IL-6, TNF-α, COX-2, tenascin-c) was significantly mitigated by AP318. Furthermore, a Western blot analysis shows a significantly lower of COX-2 protein level. The present sepsis model caused minor lung edema formation and moderate gas exchange impairment. Six hours after onset pathologic scoring showed no improvement, while gas exchange parameters and pulmonary edema formation were similar in the two groups. CONCLUSION In summary, AP318 significantly attenuated intrapulmonary inflammatory response even without the presence or resolution of severe pulmonary edema in a porcine model of systemic sepsis-associated lung injury. These findings suggest an anti-inflammatory mechanism of the lectin-like domain beyond mere edema reabsorption in endotoxemic lung injury in vivo.
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Affiliation(s)
- Erik K Hartmann
- Department of Anesthesiology, Medical Center of the Johannes Gutenberg-University, Langenbeckstrasse 1, 55131, Mainz, Germany.
| | - Alexander Ziebart
- Department of Anesthesiology, Medical Center of the Johannes Gutenberg-University, Langenbeckstrasse 1, 55131, Mainz, Germany.
| | - Rainer Thomas
- Department of Anesthesiology, Medical Center of the Johannes Gutenberg-University, Langenbeckstrasse 1, 55131, Mainz, Germany.
| | - Tanghua Liu
- Department of Anesthesiology, Medical Center of the Johannes Gutenberg-University, Langenbeckstrasse 1, 55131, Mainz, Germany.
| | - Arno Schad
- Institute of Pathology, Medical Center of the Johannes Gutenberg-University, Langenbeckstrasse 1, 55131, Mainz, Germany.
| | - Martha Tews
- Institute of Pathobiochemistry, Medical Center of the Johannes, Gutenberg-University, Duesbergweg 6, 55128, Mainz, Germany.
| | - Bernd Moosmann
- Institute of Pathobiochemistry, Medical Center of the Johannes, Gutenberg-University, Duesbergweg 6, 55128, Mainz, Germany.
| | - Jens Kamuf
- Department of Anesthesiology, Medical Center of the Johannes Gutenberg-University, Langenbeckstrasse 1, 55131, Mainz, Germany.
| | - Bastian Duenges
- Department of Anesthesiology, Medical Center of the Johannes Gutenberg-University, Langenbeckstrasse 1, 55131, Mainz, Germany.
| | - Serge C Thal
- Department of Anesthesiology, Medical Center of the Johannes Gutenberg-University, Langenbeckstrasse 1, 55131, Mainz, Germany.
| | - Matthias David
- Department of Anesthesiology, Medical Center of the Johannes Gutenberg-University, Langenbeckstrasse 1, 55131, Mainz, Germany.
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14
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Chen F, Kumar S, Yu Y, Aggarwal S, Gross C, Wang Y, Chakraborty T, Verin AD, Catravas JD, Lucas R, Black SM, Fulton DJR. PKC-dependent phosphorylation of eNOS at T495 regulates eNOS coupling and endothelial barrier function in response to G+ -toxins. PLoS One 2014; 9:e99823. [PMID: 25020117 PMCID: PMC4096401 DOI: 10.1371/journal.pone.0099823] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2014] [Accepted: 05/19/2014] [Indexed: 11/30/2022] Open
Abstract
Gram positive (G+) infections make up ∼50% of all acute lung injury cases which are characterized by extensive permeability edema secondary to disruption of endothelial cell (EC) barrier integrity. A primary cause of increased permeability are cholesterol-dependent cytolysins (CDCs) of G+-bacteria, such as pneumolysin (PLY) and listeriolysin-O (LLO) which create plasma membrane pores, promoting Ca2+-influx and activation of PKCα. In human lung microvascular endothelial cells (HLMVEC), pretreatment with the nitric oxide synthase (NOS) inhibitor, ETU reduced the ability of LLO to increase microvascular cell permeability suggesting an endothelial nitric oxide synthase (eNOS)-dependent mechanism. LLO stimulated superoxide production from HLMVEC and this was prevented by silencing PKCα or NOS inhibition suggesting a link between these pathways. Both LLO and PLY stimulated eNOS T495 phosphorylation in a PKC-dependent manner. Expression of a phosphomimetic T495D eNOS (human isoform) resulted in increased superoxide and diminished nitric oxide (NO) production. Transduction of HLMVEC with an active form of PKCα resulted in the robust phosphorylation of T495 and increased peroxynitrite production, indicative of eNOS uncoupling. To determine the mechanisms underlying eNOS uncoupling, HLMVEC were stimulated with LLO and the amount of hsp90 and caveolin-1 bound to eNOS determined. LLO stimulated the dissociation of hsp90, and in particular, caveolin-1 from eNOS. Both hsp90 and caveolin-1 have been shown to influence eNOS uncoupling and a peptide mimicking the scaffolding domain of caveolin-1 blocked the ability of PKCα to stimulate eNOS-derived superoxide. Collectively, these results suggest that the G+ pore-forming toxins promote increased EC permeability via activation of PKCα, phosphorylation of eNOS-T495, loss of hsp90 and caveolin-1 binding which collectively promote eNOS uncoupling and the production of barrier disruptive superoxide.
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Affiliation(s)
- Feng Chen
- Department of Forensic Medicine, Nanjing Medical University, Nanjing, Jiangsu, China
- Vascular Biology Center Medical College of Georgia at Georgia Regents University, Augusta, Georgia, United States of America
| | - Sanjiv Kumar
- Vascular Biology Center Medical College of Georgia at Georgia Regents University, Augusta, Georgia, United States of America
| | - Yanfang Yu
- Vascular Biology Center Medical College of Georgia at Georgia Regents University, Augusta, Georgia, United States of America
| | - Saurabh Aggarwal
- Vascular Biology Center Medical College of Georgia at Georgia Regents University, Augusta, Georgia, United States of America
| | - Christine Gross
- Vascular Biology Center Medical College of Georgia at Georgia Regents University, Augusta, Georgia, United States of America
| | - Yusi Wang
- Vascular Biology Center Medical College of Georgia at Georgia Regents University, Augusta, Georgia, United States of America
| | - Trinad Chakraborty
- Institute for Medical Microbiology, Justus Liebig University, Giessen, Germany
| | - Alexander D. Verin
- Vascular Biology Center Medical College of Georgia at Georgia Regents University, Augusta, Georgia, United States of America
| | - John D. Catravas
- Old Dominion University, Norfolk, Virginia, United States of America
| | - Rudolf Lucas
- Vascular Biology Center Medical College of Georgia at Georgia Regents University, Augusta, Georgia, United States of America
- Department of Pharmacology, Medical College of Georgia at Georgia Regents University, Augusta, Georgia, United States of America
| | - Stephen M. Black
- Vascular Biology Center Medical College of Georgia at Georgia Regents University, Augusta, Georgia, United States of America
| | - David J. R. Fulton
- Vascular Biology Center Medical College of Georgia at Georgia Regents University, Augusta, Georgia, United States of America
- Department of Pharmacology, Medical College of Georgia at Georgia Regents University, Augusta, Georgia, United States of America
- * E-mail:
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15
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Hartmann EK, Thomas R, Liu T, Stefaniak J, Ziebart A, Duenges B, Eckle D, Markstaller K, David M. TIP peptide inhalation in experimental acute lung injury: effect of repetitive dosage and different synthetic variants. BMC Anesthesiol 2014; 14:42. [PMID: 24904234 PMCID: PMC4046002 DOI: 10.1186/1471-2253-14-42] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2013] [Accepted: 05/21/2014] [Indexed: 12/17/2022] Open
Abstract
Background Inhalation of TIP peptides that mimic the lectin-like domain of TNF-α is a novel approach to attenuate pulmonary oedema on the threshold to clinical application. A placebo-controlled porcine model of acute respiratory distress syndrome (ARDS) demonstrated a reduced thermodilution-derived extravascular lung water index (EVLWI) and improved gas exchange through TIP peptide inhalation within three hours. Based on these findings, the present study compares a single versus a repetitive inhalation of a TIP peptide (TIP-A) and two alternate peptide versions (TIP-A, TIP-B). Methods Following animal care committee approval ARDS was induced by bronchoalveolar lavage followed by injurious ventilation in 21 anaesthetized pigs. A randomised-blinded three-group setting compared the single-dosed peptide variants TIP-A and TIP-B as well as single versus repetitive inhalation of TIP-A (n = 7 per group). Over two three-hour intervals parameters of gas exchange, transpulmonary thermodilution, calculated alveolar fluid clearance, and ventilation/perfusion-distribution were assessed. Post-mortem measurements included pulmonary wet/dry ratio and haemorrhage/congestion scoring. Results The repetitive TIP-A inhalation led to a significantly lower wet/dry ratio than a single dose and a small but significantly lower EVLWI. However, EVLWI changes over time and the derived alveolar fluid clearance did not differ significantly. The comparison of TIP-A and B showed no relevant differences. Gas exchange and ventilation/perfusion-distribution significantly improved in all groups without intergroup differences. No differences were found in haemorrhage/congestion scoring. Conclusions In comparison to a single application the repetitive inhalation of a TIP peptide in three-hour intervals may lead to a small additional reduction the lung water content. Two alternate TIP peptide versions showed interchangeable characteristics.
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Affiliation(s)
- Erik K Hartmann
- Department of Anaesthesiology, Medical Centre of the Johannes Gutenberg-University Mainz, Langenbeckstraße 1, 55131 Mainz, Germany
| | - Rainer Thomas
- Department of Anaesthesiology, Medical Centre of the Johannes Gutenberg-University Mainz, Langenbeckstraße 1, 55131 Mainz, Germany
| | - Tanghua Liu
- Department of Anaesthesiology, Medical Centre of the Johannes Gutenberg-University Mainz, Langenbeckstraße 1, 55131 Mainz, Germany
| | - Joanna Stefaniak
- Department of Anaesthesiology, General Critical Care Medicine and Pain Therapy, Medical University Vienna, Währinger Gürtel 18-20, 1090 Vienna, Austria
| | - Alexander Ziebart
- Department of Anaesthesiology, Medical Centre of the Johannes Gutenberg-University Mainz, Langenbeckstraße 1, 55131 Mainz, Germany
| | - Bastian Duenges
- Department of Anaesthesiology, Medical Centre of the Johannes Gutenberg-University Mainz, Langenbeckstraße 1, 55131 Mainz, Germany
| | - Daniel Eckle
- Department of Anaesthesiology, Medical Centre of the Johannes Gutenberg-University Mainz, Langenbeckstraße 1, 55131 Mainz, Germany
| | - Klaus Markstaller
- Department of Anaesthesiology, Medical Centre of the Johannes Gutenberg-University Mainz, Langenbeckstraße 1, 55131 Mainz, Germany ; Department of Anaesthesiology, General Critical Care Medicine and Pain Therapy, Medical University Vienna, Währinger Gürtel 18-20, 1090 Vienna, Austria
| | - Matthias David
- Department of Anaesthesiology, Medical Centre of the Johannes Gutenberg-University Mainz, Langenbeckstraße 1, 55131 Mainz, Germany
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Duluc L, Wojciak-Stothard B. Rho GTPases in the regulation of pulmonary vascular barrier function. Cell Tissue Res 2014; 355:675-85. [PMID: 24599334 DOI: 10.1007/s00441-014-1805-0] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2013] [Accepted: 01/10/2014] [Indexed: 12/12/2022]
Abstract
Pulmonary endothelial permeability is an important determinant of vascular adaptation to changes in oxygen tension, blood pressure, levels of growth factors or inflammatory cytokines. The Ras homologous (Rho) family of guanosine triphosphate phosphatases (Rho GTPases), key regulators of the actin cytoskeleton, regulate endothelial barrier function in response to a variety of environmental factors and signalling agents via the reorganization of the actin cytoskeleton, changes in receptor trafficking or the phosphorylation of junctional proteins. This review provides a brief summary of recent knowledge on Rho-GTPase-mediated effects on pulmonary endothelial barrier function and focuses in particular on their role in pulmonary vascular disorders, including pulmonary hypertension, chronic obstructive pulmonary disease, acute lung injury and acute respiratory distress syndrome.
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Affiliation(s)
- Lucie Duluc
- Centre for Pharmacology & Therapeutics, Imperial College London, London, UK
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Schwameis R, Eder S, Pietschmann H, Fischer B, Mascher H, Tzotzos S, Fischer H, Lucas R, Zeitlinger M, Hermann R. A FIM study to assess safety and exposure of inhaled single doses of AP301-A specific ENaC channel activator for the treatment of acute lung injury. J Clin Pharmacol 2014; 54:341-50. [PMID: 24515273 PMCID: PMC4160070 DOI: 10.1002/jcph.203] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2013] [Accepted: 10/01/2013] [Indexed: 11/05/2022]
Abstract
AP301 is an activator of ENaC-mediated Na(+) uptake for the treatment of pulmonary permeability edema in acute respiratory distress syndrome (ARDS). The purpose of this "first-in-man" study was to examine local and systemic safety and systemic exposure of ascending single doses of AP301, when inhaled by healthy male subjects. In a double-blind, placebo-controlled study, 48 healthy male subjects were randomized to 6 ascending dose groups (single doses up to 120 mg) of 8 subjects each (3:1 randomization of AP301: placebo). Serial assessments included spirometry, exhaled nitric oxide (eNO), vital signs, ECG, safety laboratory, adverse events (AE), and blood samples for the quantification of AP301 in plasma. Descriptive statistics was applied. All 48 subjects received treatment, and completed the study as per protocol. No serious, local (e.g., hoarseness, cough, bronchospasm), or dose-limiting AEs were noted. None of the assessments indicated notable dose or time-related alterations of safety outcomes. Observed AP301 systemic exposure levels were very low, with mean Cmax values of <2.5 ng/mL in the highest dose groups. Inhaled AP301 single doses up to 120 mg were safe and well tolerated by healthy male subjects. Distribution of inhaled AP301 was largely confined to the lung, as indicated by very low AP301 systemic exposure levels.
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Affiliation(s)
- Richard Schwameis
- Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Sandra Eder
- Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria
| | | | | | | | | | | | - Rudolf Lucas
- Department of Pharmacology and Toxicology, Vascular Biology Center, Georgia Health Sciences University, Augusta, GA, USA
| | - Markus Zeitlinger
- Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Robert Hermann
- Clinical Research Appliance, Heinrich-Vingerhut-Weg 3, D-63571, Gelnhausen, Germany
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Hartmann EK, Bentley A, Duenges B, Klein KU, Boehme S, Markstaller K, David M. TIP peptide inhalation in oleic acid-induced experimental lung injury: a post-hoc comparison. BMC Res Notes 2013; 6:385. [PMID: 24070340 PMCID: PMC3849219 DOI: 10.1186/1756-0500-6-385] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2013] [Accepted: 09/25/2013] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The lectin-like domain of TNF-α mimicked by an inhaled TIP peptide represents a novel approach to attenuate a pulmonary edema in respiratory failure, which is on the threshold to clinical application. In extension to a previously published study, which reported an improved pulmonary function following TIP peptide inhalation in a porcine model of lavage-induced lung injury, a post-hoc comparison to additional experiments was conducted. This analysis addresses the hypothesis that oleic acid injection-induced capillary leakage and alveolar necrosis blunts the previously reported beneficial effects of TIP peptide inhalation in a porcine model. FINDINGS Following animal care committee approval lung injury was induced by oleic acid injection in six pigs with a setting strictly according to a previously published protocol that was used for lung-lavaged pigs. Ventilation/perfusion-distribution by multiple inert gas elimination, parameters of gas exchange and pulmonary edema were assessed as surrogates of the pulmonary function. A significantly improved ventilation/perfusion-distribution following TIP inhalation was recognized only in the bronchoalveolar lavage model but not following oleic acid injection. The time course after oleic acid injection yielded no comparable impact of the TIP peptide on gas exchange and edema formation. CONCLUSIONS Reported beneficial effects of the TIP peptide on gas exchange and pulmonary edema were not reproducible in the oleic acid injection model. This analysis assumes that sustained alveolar epithelial necrosis as induced by oleic acid injection may inhibit the TIP-induced edema resolution. Regarding the on-going clinical development of the TIP peptide this approach should hardly be effective in states of severe alveolar epithelial damage.
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Affiliation(s)
- Erik K Hartmann
- Department of Anaesthesiology, Medical Centre of the Johannes Gutenberg-University, Langenbeckstr, 1, 55131 Mainz, Germany.
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Dulebo A, Ettrich R, Lucas R, Kaftan D. A computational study of the oligosaccharide binding sites in the lectin-like domain of Tumor Necrosis Factor and the TNF-derived TIP peptide. Curr Pharm Des 2013; 18:4236-43. [PMID: 22697478 DOI: 10.2174/138161212802430549] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2012] [Accepted: 06/11/2012] [Indexed: 01/18/2023]
Abstract
The lectin-like domain of Tumor Necrosis Factor (TNF), mimicked by the TIP peptide, activates amiloride-sensitive sodium uptake in type II alveolar epithelial cells and as such increases alveolar liquid clearance in dysfunctional lungs. This protective effect is blunted upon mutation of residues T105, E107 and E110 in human TNF into alanine or upon pre-incubation of the cytokine with the disaccharide N,N'-diacetylchitobiose. In this study, we used molecular docking and molecular dynamics simulation to predict the binding sites for N,N'-diacetylchitobiose and trimannose-O-ethyl in the lectin-like domain of TNF and in the TIP peptide. Specific sites (K98, S99, P100, Q102 and E116) in the three loops of the lectin-like domain provide specific binding for both oligosaccharides, but none of the residues crucial for anti-edema activity are involved in hydrogen bonding with oligosaccharides or are subjected to steric hindrance by them. These results thus suggest that neither chitobiose nor trimannose affect crucial amino acids, while they occupy the cavity in the lectin-like domain. Consequently, both crucial amino acids and the emptiness of the cavity in the lectin-like domain may be critical for TNF's lectin-like activity. Analogously, the R4, E5, P7, Y16 amino acids of the TIP peptide are involved in forming hydrogen bonds with both oligosaccharides, whereas residues T6, E8 and E11 (corresponding to T105, E107 and E110 in hTNF) play an important role in stabilizing the peptide-oligosaccharide complex, supporting the hypothesis that amino acids in the polar region (TPEGAE) of the TIP peptide represent only a partial binding motif for sugars.
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Affiliation(s)
- Alexander Dulebo
- University of South Bohemia in Ceské Budejovice, Faculty of Science, Czech Republic
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20
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Lucas R, Yang G, Gorshkov BA, Zemskov EA, Sridhar S, Umapathy NS, Jezierska-Drutel A, Alieva IB, Leustik M, Hossain H, Fischer B, Catravas JD, Verin AD, Pittet JF, Caldwell RB, Mitchell TJ, Cederbaum SD, Fulton DJ, Matthay MA, Caldwell RW, Romero MJ, Chakraborty T. Protein kinase C-α and arginase I mediate pneumolysin-induced pulmonary endothelial hyperpermeability. Am J Respir Cell Mol Biol 2012; 47:445-53. [PMID: 22582175 DOI: 10.1165/rcmb.2011-0332oc] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Antibiotics-induced release of the pore-forming virulence factor pneumolysin (PLY) in patients with pneumococcal pneumonia results in its presence days after lungs are sterile and is a major factor responsible for the induction of permeability edema. Here we sought to identify major mechanisms mediating PLY-induced endothelial dysfunction. We evaluated PLY-induced endothelial hyperpermeability in human lung microvascular endothelial cells (HL-MVECs) and human lung pulmonary artery endothelial cells in vitro and in mice instilled intratracheally with PLY. PLY increases permeability in endothelial monolayers by reducing stable and dynamic microtubule content and modulating VE-cadherin expression. These events, dependent upon an increased calcium influx, are preceded by protein kinase C (PKC)-α activation, perturbation of the RhoA/Rac1 balance, and an increase in myosin light chain phosphorylation. At later time points, PLY treatment increases the expression and activity of arginase in HL-MVECs. Arginase inhibition abrogates and suppresses PLY-induced endothelial barrier dysfunction by restoring NO generation. Consequently, a specific PKC-α inhibitor and the TNF-derived tonoplast intrinsic protein peptide, which blunts PLY-induced PKC-α activation, are able to prevent activation of arginase in HL-MVECs and to reduce PLY-induced endothelial hyperpermeability in mice. Arginase I (AI)(+/-)/arginase II (AII)(-/-) C57BL/6 mice, displaying a significantly reduced arginase I expression in the lungs, are significantly less sensitive to PLY-induced capillary leak than their wild-type or AI(+/+)/AII(-/-) counterparts, indicating an important role for arginase I in PLY-induced endothelial hyperpermeability. These results identify PKC-α and arginase I as potential upstream and downstream therapeutic targets in PLY-induced pulmonary endothelial dysfunction.
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Affiliation(s)
- Rudolf Lucas
- Vascular Biology Center and Dept. of Pharmacology and Toxicology, Georgia Health Sciences University, 1459 Laney-Walker Blvd., Augusta, GA 30912-2500, USA.
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Agonist of growth hormone-releasing hormone reduces pneumolysin-induced pulmonary permeability edema. Proc Natl Acad Sci U S A 2012; 109:2084-9. [PMID: 22308467 DOI: 10.1073/pnas.1121075109] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Aggressive treatment with antibiotics in patients infected with Streptococcus pneumoniae induces release of the bacterial virulence factor pneumolysin (PLY). Days after lungs are sterile, this pore-forming toxin can still induce pulmonary permeability edema in patients, characterized by alveolar/capillary barrier dysfunction and impaired alveolar liquid clearance (ALC). ALC is mainly regulated through Na(+) transport by the apically expressed epithelial sodium channel (ENaC) and the basolaterally expressed Na(+)/K(+)-ATPase in type II alveolar epithelial cells. Because no standard treatment is currently available to treat permeability edema, the search for novel therapeutic candidates is of high priority. We detected mRNA expression for the active receptor splice variant SV1 of the hypothalamic polypeptide growth hormone-releasing hormone (GHRH), as well as for GHRH itself, in human lung microvascular endothelial cells (HL-MVEC). Therefore, we have evaluated the effect of the GHRH agonist JI-34 on PLY-induced barrier and ALC dysfunction. JI-34 blunts PLY-mediated endothelial hyperpermeability in monolayers of HL-MVEC, in a cAMP-dependent manner, by means of reducing the phosphorylation of myosin light chain and vascular endothelial (VE)-cadherin. In human airway epithelial H441 cells, PLY significantly impairs Na(+) uptake, but JI-34 restores it to basal levels by means of increasing cAMP levels. Intratracheal instillation of PLY into C57BL6 mice causes pulmonary alveolar epithelial and endothelial hyperpermeability as well as edema formation, all of which are blunted by JI-34. These findings point toward a protective role of the GHRH signaling pathway in PLY-induced permeability edema.
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Yang G, Lucas R, Caldwell R, Yao L, Romero MJ, Caldwell RW. Novel mechanisms of endothelial dysfunction in diabetes. J Cardiovasc Dis Res 2011; 1:59-63. [PMID: 20877687 PMCID: PMC2945199 DOI: 10.4103/0975-3583.64432] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Diabetes mellitus is a major risk factor for cardiovascular morbidity and mortality. This condition increases the risk of developing coronary, cerebrovascular, and peripheral arterial disease fourfold. Endothelial dysfunction is a major contributor to the pathogenesis of vascular disease in diabetes mellitus patients and has recently received increased attention. In this review article, some recent developments that could improve the knowledge of diabetes-induced endothelial dysfunction are discussed.
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Affiliation(s)
- Guang Yang
- Department of Vascular Biology Center, Medical College of Georgia, Augusta, GA, USA
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Yang G, Hamacher J, Gorshkov B, White R, Sridhar S, Verin A, Chakraborty T, Lucas R. The Dual Role of TNF in Pulmonary Edema. J Cardiovasc Dis Res 2011; 1:29-36. [PMID: 21188088 PMCID: PMC3004168 DOI: 10.4103/0975-3583.59983] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
—Pulmonary edema, a major manifestation of left ventricular heart failure, renal insufficiency, shock, diffuse alveolar damage and lung hypersensitivity states, is a significant medical problem worldwide and can be life-threatening. The proinflammatory cytokine tumor necrosis factor (TNF) has been shown to contribute to the pathogenesis and development of pulmonary edema. However, some recent studies have demonstrated surprisingly that TNF can also promote alveolar fluid reabsorption in vivo and in vitro. This protective effect of the cytokine is mediated by the lectin-like domain of the cytokine, which is spatially distinct from the TNF receptor binding sites. The TIP peptide, a synthetic mimic of the lectin-like domain of TNF, can significantly increase alveolar fluid clearance and improve lung compliance in pulmonary edema models. In this review, we will discuss the dual role of TNF in pulmonary edema.
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Affiliation(s)
- Guang Yang
- Vascular Biology Center & Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta, GA, 30912, USA
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Grinnell KL, Harrington EO. Interplay between FAK, PKCδ, and p190RhoGAP in the regulation of endothelial barrier function. Microvasc Res 2011; 83:12-21. [PMID: 21549132 DOI: 10.1016/j.mvr.2011.04.005] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2011] [Revised: 04/15/2011] [Accepted: 04/16/2011] [Indexed: 11/16/2022]
Abstract
Disruption of either intercellular or extracellular junctions involved in maintaining endothelial barrier function can result in increased endothelial permeability. Increased endothelial permeability, in turn, allows for the unregulated movement of fluid and solutes out of the vasculature and into the surrounding connective tissue, contributing to a number of disease states, including stroke and pulmonary edema (Ermert et al., 1995; Lee and Slutsky, 2010; van Hinsbergh, 1997; Waller et al., 1996; Warboys et al., 2010). Thus, a better understanding of the molecular mechanisms by which endothelial cell junction integrity is controlled is necessary for development of therapies aimed at treating such conditions. In this review, we will discuss the functions of three signaling molecules known to be involved in regulation of endothelial permeability: focal adhesion kinase (FAK), protein kinase C delta (PKCδ), and p190RhoGAP (p190). We will discuss the independent functions of each protein, as well as the interplay that exists between them and the effects of such interactions on endothelial function.
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Affiliation(s)
- Katie L Grinnell
- Vascular Research Laboratory, Providence VA Medical Center, Department of Medicine, Warren Alpert Medical School of Brown University, Providence, RI 02908, USA
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