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Wang J, Luo J, Liu Y, Jiang Y, Qu X, Liu C, Xiang Y, Qin X. Stress stimulation promotes the injury repair process of airway epithelial cells through the [Cl -] i-FAK signaling axis. Respir Physiol Neurobiol 2024; 323:104237. [PMID: 38354845 DOI: 10.1016/j.resp.2024.104237] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2023] [Revised: 01/25/2024] [Accepted: 02/06/2024] [Indexed: 02/16/2024]
Abstract
The airway epithelium serves as a critical interface with the external environment, making it vulnerable to various external stimuli. Airway epithelial stress acts as a catalyst for the onset of numerous pulmonary and systemic diseases. Our previous studies have highlighted the impact of acute stress stimuli, especially bacterial lipopolysaccharide (LPS) and hydrogen peroxide (H2O2), on the continuous elevation of intracellular chloride concentration ([Cl-]i). However, the precise mechanism behind this [Cl-]i elevation and the consequential effects of such stress on the injury repair function of airway epithelial cells remain unclear. Our findings indicate that H2O2 induces an elevation in [Cl-]i by modulating the expression of CF transmembrane conductance regulator (CFTR) and Ca-activated transmembrane protein 16 A (TMEM16A) in airway epithelial cells (BEAS-2B), whereas LPS achieves this solely through CFTR. Subsequently, the elevated [Cl-]i level facilitated the injury repair process of airway epithelial cells by activating focal adhesion kinase (FAK). In summary, the [Cl-]i-FAK axis appears to play a promoting effect on the injury repair process triggered by stress stimulation. Furthermore, our findings suggest that abnormalities in the [Cl-]i-FAK signaling axis may play a crucial role in the pathogenesis of chronic airway diseases. Therefore, controlling the structure and function of airway epithelial barriers through the modulation of [Cl-]i holds promising prospects for future applications in managing and treating such conditions.
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Affiliation(s)
- Jia Wang
- Hunan Provincial People's Hospital, The First-affiliated Hospital of Hunan Normal University, Changsha 410016, China; Department of Physiology, School of Basic Medicine, Central South University, Changsha 410000, China
| | - Jinhua Luo
- Department of Physiology, School of Basic Medicine, Central South University, Changsha 410000, China
| | - Yanjuan Liu
- Hunan Provincial People's Hospital, The First-affiliated Hospital of Hunan Normal University, Changsha 410016, China
| | - Yu Jiang
- Hunan Provincial People's Hospital, The First-affiliated Hospital of Hunan Normal University, Changsha 410016, China
| | - Xiangping Qu
- Department of Physiology, School of Basic Medicine, Central South University, Changsha 410000, China
| | - Chi Liu
- Department of Physiology, School of Basic Medicine, Central South University, Changsha 410000, China
| | - Yang Xiang
- Department of Physiology, School of Basic Medicine, Central South University, Changsha 410000, China.
| | - Xiaoqun Qin
- Department of Physiology, School of Basic Medicine, Central South University, Changsha 410000, China.
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2
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Markasz L, Mobini-Far H, Sindelar R. Collagen type IV alpha 1 chain (COL4A1) expression in the developing human lung. BMC Pulm Med 2024; 24:75. [PMID: 38331745 PMCID: PMC10851591 DOI: 10.1186/s12890-024-02875-4] [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: 10/11/2023] [Accepted: 01/22/2024] [Indexed: 02/10/2024] Open
Abstract
BACKGROUND Collagen type IV alpha 1 chain (COL4A1) in the basement membrane is an important component during lung development, as suggested from animal models where COL4A1 has been shown to regulate alveolarization and angiogenesis. Less is known about its role in human lung development. Our aim was to study COL4A1 expression in preterm infants with different lung maturational and clinical features. METHODS COL4A1 expression in 115 lung samples from newborn infants (21-41 weeks' gestational age; 0-228 days' postnatal age [PNA]) was studied by immunohistochemistry combined with digital image analysis. Cluster analysis was performed to find subgroups according to immunohistologic and clinical data. RESULTS Patients were automatically categorized into 4 Groups depending on their COL4A1 expression. Expression of COL4A1 was mainly extracellular in Group 1, low in Group 2, intracellular in Group 3, and both extra- and intracellular in Group 4. Intracellular/extracellular ratio of COL4A1 expression related to PNA showed a distinctive postnatal maturational pattern on days 1-7, where intracellular expression of COL4A1 was overrepresented in extremely preterm infants. CONCLUSIONS COL4A1 expression seems to be highly dynamic during the postnatal life due to a possible rapid remodeling of the basement membrane. Intracellular accumulation of COL4A1 in the lungs of extremely premature infants occurs more frequently between 1 and 7 postnatal days than during the first 24 hours. In view of the lung arrest described in extremely preterm infants, the pathological and/or developmental role of postnatally increased intracellular COL4A1 as marker for basement membrane turnover, needs to be further investigated.
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Affiliation(s)
- Laszlo Markasz
- Department of Women's and Children's Health, Uppsala University, Uppsala, SE-751 85, Sweden.
| | - Hamid Mobini-Far
- Department of Pathology, Uppsala University Hospital, Uppsala, Sweden
| | - Richard Sindelar
- Department of Women's and Children's Health, Uppsala University, Uppsala, SE-751 85, Sweden
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3
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Raby KL, Michaeloudes C, Tonkin J, Chung KF, Bhavsar PK. Mechanisms of airway epithelial injury and abnormal repair in asthma and COPD. Front Immunol 2023; 14:1201658. [PMID: 37520564 PMCID: PMC10374037 DOI: 10.3389/fimmu.2023.1201658] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Accepted: 06/19/2023] [Indexed: 08/01/2023] Open
Abstract
The airway epithelium comprises of different cell types and acts as a physical barrier preventing pathogens, including inhaled particles and microbes, from entering the lungs. Goblet cells and submucosal glands produce mucus that traps pathogens, which are expelled from the respiratory tract by ciliated cells. Basal cells act as progenitor cells, differentiating into different epithelial cell types, to maintain homeostasis following injury. Adherens and tight junctions between cells maintain the epithelial barrier function and regulate the movement of molecules across it. In this review we discuss how abnormal epithelial structure and function, caused by chronic injury and abnormal repair, drives airway disease and specifically asthma and chronic obstructive pulmonary disease (COPD). In both diseases, inhaled allergens, pollutants and microbes disrupt junctional complexes and promote cell death, impairing the barrier function and leading to increased penetration of pathogens and a constant airway immune response. In asthma, the inflammatory response precipitates the epithelial injury and drives abnormal basal cell differentiation. This leads to reduced ciliated cells, goblet cell hyperplasia and increased epithelial mesenchymal transition, which contribute to impaired mucociliary clearance and airway remodelling. In COPD, chronic oxidative stress and inflammation trigger premature epithelial cell senescence, which contributes to loss of epithelial integrity and airway inflammation and remodelling. Increased numbers of basal cells showing deregulated differentiation, contributes to ciliary dysfunction and mucous hyperproduction in COPD airways. Defective antioxidant, antiviral and damage repair mechanisms, possibly due to genetic or epigenetic factors, may confer susceptibility to airway epithelial dysfunction in these diseases. The current evidence suggests that a constant cycle of injury and abnormal repair of the epithelium drives chronic airway inflammation and remodelling in asthma and COPD. Mechanistic understanding of injury susceptibility and damage response may lead to improved therapies for these diseases.
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Affiliation(s)
- Katie Louise Raby
- National Heart and Lung Institute, Imperial College London, London, United Kingdom
| | | | - James Tonkin
- National Heart and Lung Institute, Imperial College London, London, United Kingdom
- Department of Respiratory Medicine, Royal Brompton and Harefield Hospital, London, United Kingdom
| | - Kian Fan Chung
- National Heart and Lung Institute, Imperial College London, London, United Kingdom
- Department of Respiratory Medicine, Royal Brompton and Harefield Hospital, London, United Kingdom
| | - Pankaj Kumar Bhavsar
- National Heart and Lung Institute, Imperial College London, London, United Kingdom
- Department of Respiratory Medicine, Royal Brompton and Harefield Hospital, London, United Kingdom
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4
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Gadalla D, Tchoukalova YD, Lott DG. Regenerating airway epithelium using fibrous biomimetic basement membranes. J Biomed Mater Res A 2022; 110:1251-1262. [PMID: 35142434 DOI: 10.1002/jbm.a.37371] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Revised: 12/28/2021] [Accepted: 01/27/2022] [Indexed: 11/09/2022]
Abstract
There are reciprocal interactions between epithelial cells and underlying basement membrane. The resemblance of biomaterials to native basement membrane is thus critical for their success when used to regenerate epithelium-containing organs. Particularly, the use of nanofibers and the incorporation of basement membrane proteins may mimic both biophysical and biochemical properties of basement membrane, respectively. Herein we tested how electrospun polycaprolactone/heparin fibers with and without adsorbed laminin and collagen IV proteins affect epithelial cell functions. We found that airway epithelial cells attached, migrated, and proliferated on all scaffolds but protein-functionalized fibers promoted higher attachment, quicker migration, and increased proliferation. Fibers were then integrated on polyethylene scaffolds and cultured at an air-liquid interface. The detection of secretory and ciliated cell markers was higher in cells on polyethylene with fibers. These findings demonstrate that electrospun fibers incite beneficial epithelial cell responses and can be used in the fabrication of bioengineered functional epithelia.
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Affiliation(s)
- Dina Gadalla
- Head and Neck Regenerative Medicine Laboratory, Mayo Clinic Arizona, Phoenix, Arizona, USA
| | - Yourka D Tchoukalova
- Head and Neck Regenerative Medicine Laboratory, Mayo Clinic Arizona, Phoenix, Arizona, USA
| | - David G Lott
- Head and Neck Regenerative Medicine Laboratory, Mayo Clinic Arizona, Phoenix, Arizona, USA.,Division of Laryngology, Mayo Clinic Arizona, Phoenix, Arizona, USA
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5
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Liu Y, Zhou X, Hu N, Wang C, Zhao L. P311 regulates distal lung development via its interaction with several binding proteins. Mech Dev 2020; 163:103633. [PMID: 32682987 DOI: 10.1016/j.mod.2020.103633] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Revised: 05/27/2020] [Accepted: 07/03/2020] [Indexed: 01/17/2023]
Abstract
Little is known about the molecular mechanisms underlying alveolar development. P311, a putative neuronal protein originally identified for its high expression during neuronal development, has once been reported to play a potential role in distal lung generation. However, the function of this protein has been poorly understood so far. Hence, we carried out a yeast two-hybrid screen, combining with other protein-protein interaction experiments, to isolate several binding partners of P311 during lung development, which may help us explore its function. We report 7 proteins here, including Gal-1, Loxl-1 and SPARC, etc, that can interact with it. Most of them have similar spatio-temporal expression patterns to P311. In addition, it was also found that P311 could stimulate their expression indirectly in L929 mouse fibroblast. Besides, computational methods were applied to construct a P311 centered protein-protein interaction network during alveolarization, using the 7 binding partners and their protein interaction information provided by public data resources. By analyzing the structure and function of this network, the effects of P311 on lung development were further clarified and all of the bioinformatic predictions from the network could be validated by real experiments. We have found here that P311 can control lung redox events, extracellular matrix and cell cycle progression, which are all crucial to pulmonary morphogenesis. This gives us a novel thought to explore the mechanisms controlling alveolarization.
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Affiliation(s)
- Yu Liu
- Department of Biochemistry and Molecular Biology, College of Life Sciences, Nankai University, Tianjin 300071, China; Department of Computational Medicine and Bioinformatics, Medical School, University of Michigan, Ann Arbor, MI 48109, USA
| | - Xiaohai Zhou
- Department of Biochemistry and Molecular Biology, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Naiyue Hu
- Department of Biochemistry and Molecular Biology, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Chunyan Wang
- Department of Biochemistry and Molecular Biology, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Liqing Zhao
- Department of Biochemistry and Molecular Biology, College of Life Sciences, Nankai University, Tianjin 300071, China.
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6
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Lung extracellular matrix and redox regulation. Redox Biol 2016; 8:305-15. [PMID: 26938939 PMCID: PMC4777985 DOI: 10.1016/j.redox.2016.02.005] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2015] [Revised: 02/15/2016] [Accepted: 02/17/2016] [Indexed: 12/28/2022] Open
Abstract
Pulmonary fibrosis affects millions worldwide and, even though there has been a significant investment in understanding the processes involved in wound healing and maladaptive repair, a complete understanding of the mechanisms responsible for lung fibrogenesis eludes us, and interventions capable of reversing or halting disease progression are not available. Pulmonary fibrosis is characterized by the excessive expression and uncontrolled deposition of extracellular matrix (ECM) proteins resulting in erosion of the tissue structure. Initially considered an 'end-stage' process elicited after injury, these events are now considered pathogenic and are believed to contribute to the course of the disease. By interacting with integrins capable of signal transduction and by influencing tissue mechanics, ECM proteins modulate processes ranging from cell adhesion and migration to differentiation and growth factor expression. In doing so, ECM proteins help orchestrate complex developmental processes and maintain tissue homeostasis. However, poorly controlled deposition of ECM proteins promotes inflammation, fibroproliferation, and aberrant differentiation of cells, and has been implicated in the pathogenesis of pulmonary fibrosis, atherosclerosis and cancer. Considering their vital functions, ECM proteins are the target of investigation, and oxidation-reduction (redox) reactions have emerged as important regulators of the ECM. Oxidative stress invariably accompanies lung disease and promotes ECM expression directly or through the overproduction of pro-fibrotic growth factors, while affecting integrin binding and activation. In vitro and in vivo investigations point to redox reactions as targets for intervention in pulmonary fibrosis and related disorders, but studies in humans have been disappointing probably due to the narrow impact of the interventions tested, and our poor understanding of the factors that regulate these complex reactions. This review is not meant to provide a comprehensive review of this field, but rather to highlight what has been learned and to raise interest in this area in need of much attention.
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7
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Iosifidis T, Garratt LW, Coombe DR, Knight DA, Stick SM, Kicic A. Airway epithelial repair in health and disease: Orchestrator or simply a player? Respirology 2016; 21:438-48. [PMID: 26804630 DOI: 10.1111/resp.12731] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2015] [Revised: 11/01/2015] [Accepted: 12/03/2015] [Indexed: 12/21/2022]
Abstract
Epithelial cells represent the most important surface of contact in the body and form the first line of defence of the body to external environment. Consequently, epithelia have numerous roles in order to maintain a homeostatic defence barrier. Although the epithelium has been extensively studied over several decades, it remains the focus of new research, indicating a lack of understanding that continues to exist around these cells in specific disease settings. Importantly, evidence is emerging that airway epithelial cells in particular have varied complex functions rather than simple passive roles. One area of current interest is its role following injury. In particular, the epithelial-specific cellular mechanisms regulating their migration during wound repair remain poorly understood and remain an area that requires much needed investigation. A better understanding of the physiological, cellular and molecular wound repair mechanisms could assist in elucidating pathological processes that contribute to airway epithelial pathology. This review attempts to highlight migration-specific and cell-extracellular matrix (ECM) aspects of repair used by epithelial cells under normal and disease settings, in the context of human airways.
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Affiliation(s)
- Thomas Iosifidis
- School of Paediatrics and Child Health, The University of Western Australia, Nedlands, Western Australia, Australia.,Centre for Cell Therapy and Regenerative Medicine, School of Medicine and Pharmacology, The University of Western Australia and Harry Perkins Institute of Medical Research, Nedlands, Western Australia, Australia
| | - Luke W Garratt
- School of Paediatrics and Child Health, The University of Western Australia, Nedlands, Western Australia, Australia.,Telethon Kids Institute, Centre for Health Research, The University of Western Australia, Nedlands, Western Australia, Australia
| | - Deirdre R Coombe
- Centre for Cell Therapy and Regenerative Medicine, School of Medicine and Pharmacology, The University of Western Australia and Harry Perkins Institute of Medical Research, Nedlands, Western Australia, Australia.,School of Biomedical Science and Curtin Health Innovation Research Institute, Curtin University, Bentley, Western Australia, Australia
| | - Darryl A Knight
- School of Biomedical Sciences and Pharmacy, University of Newcastle, Callaghan, New South Wales, Australia.,Priority Research Centre for Asthma and Respiratory Disease, Hunter Medical Research Institute, Newcastle, New South Wales, Australia.,Department of Anesthesiology, Pharmacology and Therapeutics, University of British Columbia, Vancouver, Canada
| | - Stephen M Stick
- School of Paediatrics and Child Health, The University of Western Australia, Nedlands, Western Australia, Australia.,Centre for Cell Therapy and Regenerative Medicine, School of Medicine and Pharmacology, The University of Western Australia and Harry Perkins Institute of Medical Research, Nedlands, Western Australia, Australia.,Telethon Kids Institute, Centre for Health Research, The University of Western Australia, Nedlands, Western Australia, Australia.,Department of Respiratory Medicine, Princess Margaret Hospital for Children, Perth, Western Australia, Australia
| | - Anthony Kicic
- School of Paediatrics and Child Health, The University of Western Australia, Nedlands, Western Australia, Australia.,Centre for Cell Therapy and Regenerative Medicine, School of Medicine and Pharmacology, The University of Western Australia and Harry Perkins Institute of Medical Research, Nedlands, Western Australia, Australia.,Telethon Kids Institute, Centre for Health Research, The University of Western Australia, Nedlands, Western Australia, Australia.,Department of Respiratory Medicine, Princess Margaret Hospital for Children, Perth, Western Australia, Australia
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8
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Lee DY, Lee JH, Ahn HJ, Oh SH, Kim TH, Kim HB, Park SW, Kwon SK. Synergistic effect of laminin and mesenchymal stem cells on tracheal mucosal regeneration. Biomaterials 2015; 44:134-42. [DOI: 10.1016/j.biomaterials.2014.12.029] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2014] [Revised: 12/17/2014] [Accepted: 12/20/2014] [Indexed: 12/21/2022]
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9
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Kligys K, Wu Y, Hamill KJ, Lewandowski KT, Hopkinson SB, Budinger GRS, Jones JCR. Laminin-332 and α3β1 integrin-supported migration of bronchial epithelial cells is modulated by fibronectin. Am J Respir Cell Mol Biol 2013; 49:731-40. [PMID: 23590307 PMCID: PMC3931100 DOI: 10.1165/rcmb.2012-0509oc] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2012] [Accepted: 03/22/2013] [Indexed: 11/24/2022] Open
Abstract
The repair of the bronchiolar epithelium damaged by cell-mediated, physical, or chemical insult requires epithelial cell migration over a provisional matrix composed of complexes of extracellular matrix molecules, including fibronectin and laminin. These matrix molecules support migration and enhance cell adhesion. When cells adhere too tightly to their matrix they fail to move; but if they adhere too little, they are unable to develop the traction force necessary for motility. Thus, we investigated the relative contributions of laminin and fibronectin to bronchiolar cell adhesion and migration using the immortalized bronchial lung epithelial cell line (BEP2D) and normal human bronchial epithelial (NHBE) cells, both of which assemble a laminin α3β3γ2 (LM332)/fibronectin-rich matrix. Intriguingly, BEP2D and NHBE cells migrate significantly faster on an LM332-rich matrix than on fibronectin. Moreover, addition of fibronectin to LM332 matrix suppresses motility of both cell types. Finally, fibronectin enhances the adhesion of both BEP2D and NHBE cells to LM332-coated surfaces. These results suggest that fibronectin fine tunes LM332-mediated migration by boosting bronchiolar cell adhesion to substrate. We suggest that, during epithelial wound healing of the injured airway, fibronectin plays an important adhesive role for laminin-driven epithelial cell motility by promoting a stable cellular interaction with the provisional matrix.
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Affiliation(s)
- Kristina Kligys
- Department of Cell and Molecular Biology and Department of Medicine, Division of Pulmonary and Critical Care Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - Yvonne Wu
- Department of Cell and Molecular Biology and Department of Medicine, Division of Pulmonary and Critical Care Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - Kevin J. Hamill
- Department of Cell and Molecular Biology and Department of Medicine, Division of Pulmonary and Critical Care Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - Katherine T. Lewandowski
- Department of Cell and Molecular Biology and Department of Medicine, Division of Pulmonary and Critical Care Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - Susan B. Hopkinson
- Department of Cell and Molecular Biology and Department of Medicine, Division of Pulmonary and Critical Care Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - G. R. Scott Budinger
- Department of Cell and Molecular Biology and Department of Medicine, Division of Pulmonary and Critical Care Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - Jonathan C. R. Jones
- Department of Cell and Molecular Biology and Department of Medicine, Division of Pulmonary and Critical Care Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois
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10
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Abstract
The distal airways are covered with a heterogeneous layer of cells known as the alveolar epithelium. Alveolar epithelial cells provide the major barrier between the airspace and fluid filled tissue compartments. As such, regulation of the alveolar epithelium is critical to maintain a healthy lung and for optimal gas exchange. In this chapter, we discuss functional roles for alveolar epithelial cells with particular emphasis on intercellular junctions and communication. As a thin layer of cells directly exposed to atmospheric oxygen, alveoli are particularly sensitive to oxidant insults. Alcohol significantly diminishes the normal antioxidant reserves of the alveolar epithelium, thereby rendering it sensitized for an exaggerated damage response to acute and chronic injuries. The effects of alcohol on alveolar epithelia are discussed along with open questions and potential therapeutic targets to prevent the pathophysiology of alcoholic lung disease.
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11
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Xiao H, Li DX, Liu M. Knowledge translation: airway epithelial cell migration and respiratory diseases. Cell Mol Life Sci 2012; 69:4149-62. [PMID: 22718093 PMCID: PMC11115183 DOI: 10.1007/s00018-012-1044-z] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2011] [Revised: 05/23/2012] [Accepted: 05/25/2012] [Indexed: 12/17/2022]
Abstract
Airway epithelial cell migration is essential for lung development and growth, as well as the maintenance of respiratory tissue integrity. This vital cellular process is also important for the repair and regeneration of damaged airway epithelium. More importantly, several lung diseases characterized by aberrant tissue remodeling result from the improper repair of damaged respiratory tissue. Epithelial cell migration relies upon extracellular matrix molecules and is further regulated by numerous local, neuronal, and hormonal factors. Under inflammatory conditions, cell migration can also be stimulated by certain cytokines and chemokines. Many well-known environmental factors involved in the pathogenesis of chronic lung diseases (e.g., cigarette smoking, air pollution, alcohol intake, inflammation, viral and bacterial infections) can inhibit airway epithelial cell migration. Further investigation of cellular and molecular mechanisms of cell migration with advanced techniques may provide knowledge that is relevant to physiological and pathological conditions. These studies may eventually lead to the development of therapeutic interventions to improve lung repair and regeneration and to prevent aberrant remodeling in the lung.
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Affiliation(s)
- Helan Xiao
- Latner Thoracic Surgery Research Laboratories, Toronto General Research Institute, University Health Network, Toronto, ON Canada
- Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, ON Canada
| | - Debbie X. Li
- Latner Thoracic Surgery Research Laboratories, Toronto General Research Institute, University Health Network, Toronto, ON Canada
| | - Mingyao Liu
- Latner Thoracic Surgery Research Laboratories, Toronto General Research Institute, University Health Network, Toronto, ON Canada
- Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, ON Canada
- Departments of Surgery and Medicine, Faculty of Medicine, University of Toronto, Room TMDT 2-814, 101 College Street, Toronto, ON M5G 1L7 Canada
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12
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Abstract
COPD is a worldwide public health problem that reduces the quality of life. The exact pathways by which CS and other environmental toxins produce COPD are not known. Currently, the leading candidates are (1) the protease-antiprotease hypothesis, (2) the Dutch hypothesis, (3) the British hypothesis, and the (4) autoimmunity hypothesis. Given the heterogeneity of the disease (and phenotypes), it is probably unrealistic that one pathway will fully explain COPD pathophysiology.
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Affiliation(s)
- Anthony Tam
- Department of Medicine, The UBC James Hogg Research Centre, Providence Heart and Lung Centre, University of British Columbia, Vancouver, British Columbia, Canada
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13
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Tam A, Wadsworth S, Dorscheid D, Man SFP, Sin DD. The airway epithelium: more than just a structural barrier. Ther Adv Respir Dis 2011; 5:255-73. [PMID: 21372121 DOI: 10.1177/1753465810396539] [Citation(s) in RCA: 156] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The mammalian airway is lined by a variety of specialized epithelial cells that not only serve as a physical barrier but also respond to environment-induced damage through the release of biologically active factors and constant cellular renewal. The lung epithelium responds to environmental insults such as pathogens, cigarette smoke and pollution by secreting inflammatory mediators and antimicrobial peptides, and by recruiting immune cells to the site of infection or damage. When the epithelium is severely damaged, basal cells and Clara cells that have stem-cell-like properties are capable of self-renewal and proliferation in the affected area, to repair the damage. In order to effectively fight off infections, the epithelium requires the assistance of neutrophils recruited from the peripheral circulation through transendothelial followed by transepithelial migration events. Activated neutrophils migrate across the epithelium through a series of ligand-receptor interactions to the site of injury, where they secrete proteolytic enzymes and oxidative radicals for pathogen destruction. However, chronic activation and recruitment of neutrophils in airway diseases such as chronic obstructive pulmonary disease and asthma has been associated with tissue damage and disease severity. In this paper, we review the current understanding of the airway epithelial response to injury and its interaction with inflammatory cells, in particular the neutrophil.
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Affiliation(s)
- Anthony Tam
- The UBC James Hogg Research Centre, Providence Heart and Lung Centre and Department of Medicine, University of British Columbia, UBC, Vancouver, BC, Canada
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14
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Zander DS, Popper HH, Jagirdar J, Haque AK, Cagle PT, Barrios R. Epithelial Repair and Regeneration. MOLECULAR PATHOLOGY OF LUNG DISEASES 2010; 1. [PMCID: PMC7147447 DOI: 10.1007/978-0-387-72430-0_45] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Contact with the environment positions the respiratory epithelium at risk for acute and chronic injury from infectious pathogens, noxious agents, and inflammatory processes. Thus, to protect gas transfer within the lung the epithelium is programmed for routine maintenance and repair. Programs for repair are directed by epithelial, mesenchymal, and inflammatory signals that collectively constitute highly regulated networks. Principal components of the repair network are developmental morphogens, integrin and growth factor signaling molecules, and transcription factors. The epithelium responds to these signals with a remarkable plasticity and is bulwarked by a population of lung progenitor cells to ensure maintenance and repair for fluid balance and host defense functions.
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Affiliation(s)
- Dani S. Zander
- grid.240473.60000000405439901Department of Pathology, Penn State Milton S. Hershey Medical Center, Hershey, PA USA
| | - Helmut H. Popper
- grid.11598.340000000089882476Institute of Pathology, Laboratories for Molecular Cytogenetics, Medical University of Graz, Graz, Austria
| | - Jaishree Jagirdar
- grid.267309.90000000106295880Department of Pathology, University of Texas Health Science Center, San Antonio, TX USA
| | - Abida K. Haque
- grid.5386.8000000041936877XWeill Medical College of Cornell University, New York, NY ,grid.415073.4Department of Pathology, San Jacinto Methodist Hospital, Baytown, TX USA
| | - Philip T. Cagle
- grid.5386.8000000041936877XPathology and Laboratory Medicine, Weill Medical College of Cornell University, New York, NY ,grid.63368.380000000404450041The Methodist Hospital, Houston, TX USA
| | - Roberto Barrios
- grid.5386.8000000041936877XPathology and Laboratory Medicine, Weill Medical College of Cornell University, New York, NY ,grid.63368.380000000404450041The Methodist Hospital, Houston, TX USA
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15
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Desai LP, White SR, Waters CM. Cyclic mechanical stretch decreases cell migration by inhibiting phosphatidylinositol 3-kinase- and focal adhesion kinase-mediated JNK1 activation. J Biol Chem 2010; 285:4511-9. [PMID: 20018857 PMCID: PMC2836056 DOI: 10.1074/jbc.m109.084335] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2009] [Revised: 11/30/2009] [Indexed: 01/11/2023] Open
Abstract
Epithelial cell migration during wound healing requires coordinated signaling pathways that direct polarization of the leading and trailing ends of the cells, cytoskeletal organization, and remodeling of focal adhesions. These inherently mechanical processes are disrupted by cyclic stretch (CS), but the specific signaling molecules involved in this disruption are not well understood. In this study, we demonstrate that inhibition of phosphatidylinositol 3-kinase (PI3K) or expression of a dominant-negative form of PI3K caused inhibition of airway epithelial cell wound closure. CS caused a sustained decrease in activation of PI3K and inhibited wound healing. Expression of constitutively active PI3K stimulated translocation of Tiam1 to the membrane, increased Rac1 activity, and increased wound healing of airway epithelial cells. Increased Rac1 activity resulted in increased phosphorylation of JNK1. PI3K activation was not regulated by association with focal adhesion kinase. Restoration of efficient cell migration during CS required coexpression of constitutively active PI3K, focal adhesion kinase, and JIP3.
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Affiliation(s)
| | - Steven R. White
- the Section of Pulmonary and Critical Care Medicine, University of Chicago, Chicago, Illinois 60637
| | - Christopher M. Waters
- From the Departments of Physiology
- Medicine, and
- Biomedical Engineering, University of Tennessee Health Science Center, Memphis, Tennessee 38163 and
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16
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Ngan DA, Vickerman SV, Granville DJ, Man SFP, Sin DD. The possible role of granzyme B in the pathogenesis of chronic obstructive pulmonary disease. Ther Adv Respir Dis 2009; 3:113-29. [PMID: 19638369 DOI: 10.1177/1753465809341965] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Chronic obstructive pulmonary disease (COPD) is a highly prevalent inflammatory lung condition characterized by airways disease and emphysema, and the precise mechanism of pathogenesis is poorly understood. The consistent features of COPD include protease-antiprotease imbalance, inflammation and accelerated aging caused by apoptosis or senescence. One family of molecules involved in all of these processes is the granzymes, serine proteases with the best-known member being granzyme B (GzmB). The majority of GzmB is released unidirectionally towards target cells, but GzmB can also be released nonspecifically and escape into the extracellular environment. GzmB is capable of cleaving extracellular matrix (ECM) proteins in vitro, and the accumulation of GzmB in the extracellular milieu during chronic inflammation in COPD could contribute to ECM degradation and remodelling and, consequently, the emphysematous phenotype in the lung. Preliminary studies suggest that increased GzmB expression is associated with increased COPD severity, and this may represent a promising new target for drug and biomarker discovery in COPD. In this paper, we review the potential pathogenic contributions of GzmB to the pathogenesis of COPD.
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Affiliation(s)
- David A Ngan
- James Hogg Research Laboratories, Providence Heart + Lung Institute at St. Paul's Hospital and Department of Medicine, University of British Columbia, Vancouver, BC, Canada
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17
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Desai LP, White SR, Waters CM. Mechanical stretch decreases FAK phosphorylation and reduces cell migration through loss of JIP3-induced JNK phosphorylation in airway epithelial cells. Am J Physiol Lung Cell Mol Physiol 2009; 297:L520-9. [PMID: 19574423 DOI: 10.1152/ajplung.00076.2009] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
JNK is a nonreceptor kinase involved in the early events that signal cell migration after injury. However, the linkage to early signals required to initiate the migration response to JNK has not been defined in airway epithelial cells, which exist in an environment subjected to cyclic mechanical strain (MS). The present studies demonstrate that the JNK/stress-activated protein kinase-associated protein 1 (JSAP1; also termed JNK-interacting protein 3, JIP3), a scaffold factor for MAPK cascades that links JNK activation to focal adhesion kinase (FAK), are both associated and activated following mechanical injury in 16HBE14o- human airway epithelial cells and that both FAK and JIP3 phosphorylation seen after injury are decreased in cells subjected to cyclic MS. Overexpression of either wild-type (WT)-FAK or WT-JIP3 enhanced phosphorylation and kinase activation of JNK and reduced the inhibitory effect of cyclic MS. These results suggest that cyclic MS impairs signaling of cell migration after injury via a pathway that involves FAK-JIP3-JNK.
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Affiliation(s)
- Leena P Desai
- Dept. of Physiology, The Univ. of Tennessee Health Science Center, 894 Union Ave, Rm. 426, Memphis, TN 38163-0001, USA
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18
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Koval M, Ward C, Findley MK, Roser-Page S, Helms MN, Roman J. Extracellular matrix influences alveolar epithelial claudin expression and barrier function. Am J Respir Cell Mol Biol 2009; 42:172-80. [PMID: 19423774 DOI: 10.1165/rcmb.2008-0270oc] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
The lung is dynamically remodeled in response to injury, which alters extracellular matrix composition, and can lead to either healthy or impaired lung regeneration. To determine how changes in extracellular matrix can influence alveolar epithelial barrier function, we examined the expression and function of tight junction proteins by rat alveolar epithelial type II cells cultured on one of three different matrix components: type I collagen or fibronectin, matrix glycoproteins which are highly expressed in injured lungs, or laminin, a basement membrane matrix component. Of note, alveolar epithelial cells cultured for 2 days on fibronectin formed high-resistance barriers and showed continuous claudin-3 and claudin-18 localization to the plasma membrane, as opposed to cells cultured on either type I collagen or laminin, which had low resistance monolayers and had areas of cell-cell contact that were claudin deficient. The barrier formed by cells cultured on fibronectin also had preferential permeability to chloride as compared with sodium. Regardless of the initial matrix composition, alveolar epithelial cells cultured for 5 days formed high-resistance barriers, which correlated with increased claudin-18 localization to the plasma membrane and an increase in zonula occludens-1. Day 5 cells on laminin had significantly higher resistance than cells on either fibronectin or type I collagen. Thus, although alveolar epithelial cells on fibronectin formed rapid barriers, it was at the expense of producing an optimized barrier.
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Affiliation(s)
- Michael Koval
- Department of Medicine, Division of Pulmonary, Allergy, and Critical Care Medicine, Emory University School of Medicine, Whitehead Biomedical Research Building, 615 Michael St., Suite 205, Atlanta, GA 30322, USA.
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19
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Ito K, Kon S, Nakayama Y, Kurotaki D, Saito Y, Kanayama M, Kimura C, Diao H, Morimoto J, Matsui Y, Uede T. The differential amino acid requirement within osteopontin in alpha4 and alpha9 integrin-mediated cell binding and migration. Matrix Biol 2008; 28:11-9. [PMID: 19000758 DOI: 10.1016/j.matbio.2008.10.002] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2008] [Revised: 09/02/2008] [Accepted: 10/01/2008] [Indexed: 11/16/2022]
Abstract
Osteopontin (OPN) contains at least two major integrin recognition domains, Arg159-Gly-Asp161 (RGD) and Ser162-Val-Val-Tyr-Gly-Leu-Arg168 (SVVYGLR), recognized by alphavbeta3 and alpha5beta1 and alpha4 and alpha9 integrins, respectively. OPN is specifically cleaved by thrombin and matrix metalloproteinase (MMP)-3 or MMP-7 at a position of Arg168/Ser169 (R/S) and Gly166/Leu167 (G/L), respectively. We in this study examined the requirement of residues within SVVYGLR for the alpha4 and alpha9 integrin recognition and how MMP-cleavage influences the integrin recognition. The residues, Val164, Tyr165, and Leu167 are critical for alpha4 and alpha9 integrin recognition in both cell adhesion and cell migration. The residue Arg168 is additionally required for alpha9 integrin recognition in cell adhesion and this explains why alpha9 integrin binds to only thrombin cleaved form of OPN. alpha4 integrin is able to bind to SVVYG (MMP-cleaved form of RAA OPN-N half), while alpha9 integrin is not, supporting the above notion that Arg168 is additionally required for alpha9 integrin-mediated cell adhesion. The residue Val163 is important for alpha4, but not for alpha9 integrin recognition in cell migration. Importantly, we found that the replacement of Arg168 by Ala (R168A mutant) induces the augmentation of cell migration via alpha4 and alpha9 integrins.
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Affiliation(s)
- Koyu Ito
- Division of Molecular Immunology, Institute for Genetic Medicine, Hokkaido University, Kita-15, Nishi-7, Kita-ku, Sapporo, 060-0815, Japan
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20
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Atkinson JJ, Adair-Kirk TL, Kelley DG, Demello D, Senior RM. Clara cell adhesion and migration to extracellular matrix. Respir Res 2008; 9:1. [PMID: 18179694 PMCID: PMC2249579 DOI: 10.1186/1465-9921-9-1] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2007] [Accepted: 01/07/2008] [Indexed: 11/10/2022] Open
Abstract
Background Clara cells are the epithelial progenitor cell of the small airways, a location known to be important in many lung disorders. Although migration of alveolar type II and bronchiolar ciliated epithelial cells has been examined, the migratory response of Clara cells has received little attention. Methods Using a modification of existing procedures for Clara cell isolation, we examined mouse Clara cells and a mouse Clara-like cell line (C22) for adhesion to and migration toward matrix substrate gradients, to establish the nature and integrin dependence of migration in Clara cells. Results We observed that Clara cells adhere preferentially to fibronectin (Fn) and type I collagen (Col I) similar to previous reports. Migration of Clara cells can be directed by a fixed gradient of matrix substrates (haptotaxis). Migration of the C22 cell line was similar to the Clara cells so integrin dependence of migration was evaluated with this cell line. As determined by competition with an RGD containing-peptide, migration of C22 cells toward Fn and laminin (Lm) 511 (formerly laminin 10) was significantly RGD integrin dependent, but migration toward Col I was RGD integrin independent, suggesting that Clara cells utilize different receptors for these different matrices. Conclusion Thus, Clara cells resemble alveolar type II and bronchiolar ciliated epithelial cells by showing integrin mediated pro-migratory changes to extracellular matrix components that are present in tissues after injury.
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Affiliation(s)
- Jeffrey J Atkinson
- Department of Internal Medicine, Pulmonary and Critical Care Division, Washington University School of Medicine, St, Louis, MO, USA.
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21
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PERSSON CGA, ERJEFÄLT JS, ERJEFÄLT I, KORSGREN MC, NILSSON MC, SUNDLER F. Epithelial shedding-restitution as a causative process in airway inflammation. Clin Exp Allergy 2006. [DOI: 10.1111/j.1365-2222.1996.tb00604.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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22
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Spurzem JR, Veys T, Devasure J, Sisson JH, Wyatt TA. Ethanol treatment reduces bovine bronchial epithelial cell migration. Alcohol Clin Exp Res 2005; 29:485-92. [PMID: 15834212 DOI: 10.1097/01.alc.0000158830.21657.bb] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Chronic ethanol abuse is associated with significant lung disease. Excessive alcohol intake increases risk for a variety of respiratory tract diseases, including pneumonia and bronchitis. Damage to airway epithelium is critical to the pathogenesis of airway disorders such as chronic bronchitis and chronic obstructive pulmonary disease. The ability of the airway epithelium to repair itself is an important step in the resolution of airway inflammation and disease. Ethanol exposure is known to modulate signaling systems in bronchial epithelial cells. We hypothesize that chronic ethanol exposure down-regulates the adenosine 3':5'-cyclic monophosphate signaling cascade in airway epithelial cells, resulting in decreased epithelial cell migration and repair. METHODS We evaluated the effect of ethanol on primary cultures of bovine bronchial epithelial cells in in vitro models of cell migration, wound repair, cell attachment, and cell spreading. RESULTS Ethanol causes a concentration-dependent effect on closure of mechanical wounds in cell monolayers. Pretreatment of cells with 100 mm ethanol for 24 hr further slows wound closure. Ethanol pretreatment also reduced the protein kinase A response to wounding and made the cells unresponsive to stimuli of protein kinase A that accelerate wound closure. The effects of ethanol on cell migration in wound closure were confirmed in another assay of migration, the Boyden chamber cell migration assay. Prolonged treatment with ethanol also reduced other cell functions, such as spreading and attachment, which are necessary for epithelial repair. CONCLUSIONS Ethanol modulates signaling systems that are relevant to airway injury and repair, suggesting that chronic, heavy ethanol ingestion has a detrimental impact on airway repair. Impaired response to inflammation and injury may contribute to chronic airway disease.
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Affiliation(s)
- John R Spurzem
- Department of Internal Medicine, Omaha Veterans Affairs Medical Center, Omaha, Nebraska 68198-5300, USA.
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23
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Sacco O, Silvestri M, Sabatini F, Sale R, Defilippi AC, Rossi GA. Epithelial cells and fibroblasts: structural repair and remodelling in the airways. Paediatr Respir Rev 2004; 5 Suppl A:S35-40. [PMID: 14980241 DOI: 10.1016/s1526-0542(04)90008-5] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Extensive lesions and changes in the architecture of the airway walls are commonly described in patients with respiratory infections, asthma, chronic bronchitis and interstitial lung diseases. Current knowledge identifies in airway epithelial cells and in fibroblasts the two cell types mainly involved in tissue repair after injury. During inflammatory respiratory disorders, extensive injury of airway epithelium may occur, with shedding of a large sheet of damaged cells in the bronchial and alveolar lumen but also with activation of the surviving epithelial cells and of the underlying fibroblasts. Indeed, besides acting as a physical and functional barrier to external agents, the epithelial surface of the bronchi has the capability to modulate the repair processes through the secretion of extracellular matrix proteins and the interaction with interstitial fibroblasts. Besides releasing pro-inflammatory cytokines and chemokines, the surviving epithelial cells and the underlying fibroblasts secrete factors contributing to airway repair, including the formation of the provisional extracellular matrix. This is indeed the substrate to which the epithelial cells at the edge of the lesion can attach to migrate in order to reconstitute the surface layer. In these processes airway epithelial cells receive the support of bronchial wall fibroblasts which actively release cytokines stimulating epithelial cell functions.
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Affiliation(s)
- Oliviero Sacco
- Pulmonary Division, G Gaslini Institute, 16148 Genoa, Italy
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24
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Abstract
The major function of the respiratory epithelium was once thought to be that of a physical barrier. However, it constitutes the interface between the internal milieu and the external environment as well as being a primary target for inhaled respiratory drugs. It also responds to changes in the external environment by secreting a large number of molecules and mediators that signal to cells of the immune system and underlying mesenchyme. Thus, the epithelium is in a unique position to translate gene-environment interactions. Normally, the epithelium has a tremendous capacity to repair itself following injury. However, evidence is rapidly accumulating to show that the airway epithelium of asthmatics is abnormal and has increased susceptibility to injury compared to normal epithelium. Areas of detachment and fragility are a characteristic feature not observed in other inflammatory diseases such as COPD. In addition to being more susceptible to damage, normal repair processes are also compromised. Failure of appropriate growth and differentiation of airway epithelial cells will cause persistent mucosal injury. The response to traditional therapy such as glucocorticoids may also be compromised. However, whether the differences observed in asthmatic epithelium are a cause of or secondary to the development of the disease remains unanswered. Strategies to address this question include careful examination of the ontogeny of the disease in children and use of gene array technology should provide some important answers, as well as allow a better understanding of the critical role that the epithelium plays under normal conditions and in diseases such as asthma.
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Affiliation(s)
- Darryl A Knight
- Asthma and Allergy Research Institute, Sir Charles Gairdner Hospital, Nedlands, Western Australia, Australia.
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25
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Genden EM, Iskander A, Bromberg JS, Mayer L. The kinetics and pattern of tracheal allograft re-epithelialization. Am J Respir Cell Mol Biol 2003; 28:673-81. [PMID: 12760965 DOI: 10.1165/rcmb.2002-0214oc] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Extensive tracheal defects may pose a life-threatening dilemma. Although tracheal transplantation may represent a reconstructive solution, very little is known regarding the immunobiology and behavior of tracheal allografts. The objective of this study was to assess the pattern and kinetics of re-epithelialization of orthotopic tracheal allografts in immunosuppressed recipients. Thirty-eight age-matched mice were randomly assigned to five experimental groups. BALB/c donor tracheal segments were orthotopically transplanted into either syngeneic BALB/c or MHC mismatched allogeneic C57BL/6 recipients with and without immunosuppression. On post-transplant days 7, 14, 28, 48, and 62, animals from each group were evaluated by serial histology, electron microscopy, and serial immunohistochemical analysis for mucosal phenotype, re-epithelialization pattern, and lymphocyte subpopulations. Nonimmunosuppressed recipients underwent recipient-derived basal cell re-epithelialization by Day 48, with differentiation into a sparse population of ciliated columnar epithelium by Day 62, whereas immunosuppressed recipients underwent basal cell re-epithelialization 28 d after transplantation and differentiation into a dense population of ciliated columnar epithelium by Day 48. The re-epithelialization process occurred in a definable pattern that was significantly enhanced with the addition of immunosuppression. Orthotopic tracheal transplants undergo progressive re-epithelialization with recipient-derived basal cells that differentiate into ciliated columnar epithelium in a definable pattern that is enhanced with the addition of immunosuppression.
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Affiliation(s)
- Eric M Genden
- Department of Otolaryngology-Head and Neck Surgery, Mount Sinai School of Medicine, One Gustave Levy Place, New York, NY 10029, USA.
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26
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Koval M. Sharing signals: connecting lung epithelial cells with gap junction channels. Am J Physiol Lung Cell Mol Physiol 2002; 283:L875-93. [PMID: 12376339 DOI: 10.1152/ajplung.00078.2002] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Gap junction channels enable the direct flow of signaling molecules and metabolites between cells. Alveolar epithelial cells show great variability in the expression of gap junction proteins (connexins) as a function of cell phenotype and cell state. Differential connexin expression and control by alveolar epithelial cells have the potential to enable these cells to regulate the extent of intercellular coupling in response to cell stress and to regulate surfactant secretion. However, defining the precise signals transmitted through gap junction channels and the cross talk between gap junctions and other signaling pathways has proven difficult. Insights from what is known about roles for gap junctions in other systems in the context of the connexin expression pattern by lung cells can be used to predict potential roles for gap junctional communication between alveolar epithelial cells.
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Affiliation(s)
- Michael Koval
- Department of Physiology and Institute for Environmental Medicine, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104, USA.
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27
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Spurzem JR, Gupta J, Veys T, Kneifl KR, Rennard SI, Wyatt TA. Activation of protein kinase A accelerates bovine bronchial epithelial cell migration. Am J Physiol Lung Cell Mol Physiol 2002; 282:L1108-16. [PMID: 11943677 DOI: 10.1152/ajplung.00148.2001] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Bronchial epithelial cell migration is required for the repair of damaged airway epithelium. We hypothesized that bronchial epithelial cell migration during wound repair is influenced by cAMP and the activity of its cyclic nucleotide-dependent protein kinase, protein kinase A (PKA). We found that, when confluent monolayers of bronchial epithelial cells are wounded, an increase in PKA activity occurs. Augmentation of PKA activity with a cell-permeable analog of cAMP, dibutyryl adenosine 3',5'-cyclic monophosphate, isoproterenol, or a phosphodiesterase inhibitor accelerated migration of normal bronchial epithelial cells in in vitro wound closure assays and Boyden chamber migration assays. A role for PKA activity was also confirmed with a PKA inhibitor, KT-5720, which reduced stimulated migration. Augmentation of PKA activity reduced the levels of active Rho and the formation of focal adhesions. These studies suggest that PKA activation modulates Rho activity, migration mechanisms, and thus bronchial epithelial repair mechanisms.
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Affiliation(s)
- John R Spurzem
- Department Of Veterans Affairs Medical Center, Omaha, Nebraska 68105, USA.
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28
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Michaelson JE, Ritzenthaler JD, Roman J. Regulation of serum-induced fibronectin expression by protein kinases, cytoskeletal integrity, and CREB. Am J Physiol Lung Cell Mol Physiol 2002; 282:L291-301. [PMID: 11792634 DOI: 10.1152/ajplung.00445.2000] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Lung injury, characterized by the flooding of interstitial and alveolar spaces with serum proteins, induces the expression of fibronectin (FN). This cell-adhesive extracellular matrix (ECM) glycoprotein is believed to modulate inflammation and wound repair. Murine NIH/3T3 fibroblasts transfected with a 1.2-kb human FN promoter-reporter gene were studied to gain insight into the mechanisms involved in the induction of FN by serum. Transcription of the FN gene, followed by FN protein production, was enhanced by 10% fetal bovine serum. This effect was blocked by inhibitors of protein kinase C and mitogen-activated protein kinases. ECMs typically found in injured tissues (i.e., type I collagen, fibrin, and FN) had no effect. Conversely, disruption of actin microfilaments inhibited, whereas disruption of microtubular assembly enhanced, the serum-induced FN response. The stimulatory effects of serum and microtubular disruption on FN gene transcription were related to increased DNA binding of the transcription factor cAMP response element binding protein. The data suggest that regulation of serum-induced FN expression in fibroblasts is dependent on protein kinases and on cytoskeletal integrity.
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Affiliation(s)
- Jeffrey E Michaelson
- Division of Pulmonary and Critical Care Medicine, Atlanta Veterans Affairs Medical Center and Emory University School of Medicine, Atlanta, Georgia 30033, USA
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29
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Oertel M, Graness A, Thim L, Bühling F, Kalbacher H, Hoffmann W. Trefoil factor family-peptides promote migration of human bronchial epithelial cells: synergistic effect with epidermal growth factor. Am J Respir Cell Mol Biol 2001; 25:418-24. [PMID: 11694446 DOI: 10.1165/ajrcmb.25.4.4429] [Citation(s) in RCA: 83] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
A process termed "restitution" enables rapid repair of the respiratory epithelium by migration of neighbouring cells. Mucin-associated TFF-peptides (formerly P-domain peptides or trefoil factors) are typical motogens enhancing migration of cells in various in vitro models mimicking restitution of the intestine. The human bronchial epithelial cell line BEAS-2B was used as a model system of airway restitution. The motogenic activities of recombinant human TFF2 as well as porcine TFF2 were demonstrated by in vitro wound healing assays of BEAS-2B cells. TFF2 did not induce phosphorylation of the epidermal growth factor (EGF) receptor. EGF was capable of enhancing the motogenic effect of human TFF2 at a concentration of 3 x 10(-10) M whereas EGF itself (i.e., in the absence of TFF2) did not stimulate migration at this low concentration. Furthermore, TFF2 as well as monomeric and dimeric forms of TFF3 enhanced migration of BEAS-2B cells in Boyden chambers. Motogenic activity of TFF2 was also shown for normal human bronchial epithelial (NHBE) cells in Boyden chambers. These results suggest that TFF-peptides act as motogens in the human respiratory epithelium triggering rapid repair of damaged mucosa in the course of airway diseases such as asthma.
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Affiliation(s)
- M Oertel
- Institut für Molekularbiologie und Medizinische Chemie, Otto-von-Guericke-Universität, Leipziger Strasse 44, D-39120 Magdeburg, Germany
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30
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Knight D. Leukaemia inhibitory factor (LIF): a cytokine of emerging importance in chronic airway inflammation. Pulm Pharmacol Ther 2001; 14:169-76. [PMID: 11448143 DOI: 10.1006/pupt.2001.0282] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Inflammation is a complex set of mechanisms by which tissues respond to an injury. These responses involve the coordinated interaction between the nervous and immune systems. An integral part of this interaction is the release of a variety of cytokines that regulate cellular and molecular responses. Leukaemia Inhibitory Factor (LIF), a member of the IL-6 family of cytokines, has been shown to be an integral component of the interface between nerves and the immune system. However, little is known about this cytokine in the context of normal lung function or indeed, inflammation. Evidence is emerging that this cytokine may play an important role in regulating the neural-immune system interaction during acute inflammatory insult and the subsequent healing and restitution process. However, LIF may act as either a pro- or antiinflammatory cytokine, depending on the cell type and a number of other variables. In this review, the role of LIF in airway inflammation and resolution of inflammation is discussed. In particular, recent work suggesting that LIF is a mediator of bi-directional cross-talk between neural tissue and the immune system is highlighted.
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Affiliation(s)
- D Knight
- Asthma & Allergy Research Institute, Department of Medicine, University of Western Australia, Perth, WA, Australia.
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31
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Li XF, Thinakaran G, Sisodia SS, Yu FS. Amyloid precursor-like protein 2 promotes cell migration toward fibronectin and collagen IV. J Biol Chem 1999; 274:27249-56. [PMID: 10480944 DOI: 10.1074/jbc.274.38.27249] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Previous studies have established that in response to wounding, the expression of amyloid precursor-like protein 2 (APLP2) in the basal cells of migrating corneal epithelium is greatly up-regulated. To further our understanding of the functional significance of APLP2 in wound healing, we have measured the migratory response of transfected Chinese hamster ovary (CHO) cells expressing APLP2 isoforms to a variety of extracellular matrix components including laminin, collagen types I, IV, and VII, fibronectin, and heparan sulfate proteoglycans (HSPGs). CHO cells overexpressing either of two APLP2 variants, differing in chondroitin sulfate (CS) attachment, exhibit a marked increase in chemotaxis toward type IV collagen and fibronectin but not to laminin, collagen types I and VII, and HSPGs. Cells overexpressing APLP2-751 (CS-modified) exhibited a greater migratory response to fibronectin and type IV collagen than their non-CS-attached counterparts (APLP2-763), suggesting that CS modification enhanced APLP2 effects on cell migration. Moreover, in the presence of chondroitin sulfate, transfectants overexpressing APLP2-751 failed to exhibit this enhanced migration toward fibronectin. The APLP2-ECM interactions were also explored by solid phase adhesion assays. While overexpression of APLP2 isoforms moderately enhanced CHO adhesion to laminin, collagen types I and VII, and HSPGs lines, especially those overexpressing APLP2-751, exhibited greatly increased adhesion to type IV collagen and fibronectin. These observations suggest that APLP2 contributes to re-epithelialization during wound healing by supporting epithelial cell adhesion to fibronectin and collagen IV, thus influencing their capacity to migrate over the wound bed. Furthermore, APLP2 interactions with fibronectin and collagen IV appear to be potentiated by the addition of a CS chain to the core proteins.
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Affiliation(s)
- X F Li
- Schepens Eye Research Institute, Harvard Medical School, Boston, Massachusetts 02114, USA
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White SR, Dorscheid DR, Rabe KF, Wojcik KR, Hamann KJ. Role of very late adhesion integrins in mediating repair of human airway epithelial cell monolayers after mechanical injury. Am J Respir Cell Mol Biol 1999; 20:787-96. [PMID: 10101012 DOI: 10.1165/ajrcmb.20.4.3318] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Repair of the airway epithelium after injury requires that processes such as adhesion and cell migration occur in a defined order. Both of these processes depend on interactions between extracellular matrix (ECM) proteins and appropriate integrins. To study these interactions, we examined monolayer wound repair in a cultured human airway epithelial cell line, 16HBE14o-. Wounds created in confluent monolayers grown on either collagen-IV, laminin-1, or laminin-2 matrix closed quickly in response to 15 ng/ml epidermal growth factor (EGF). Concurrent treatment of cells grown on each matrix protein with EGF and a monoclonal antibody (mAb) to beta1-integrin inhibited wound closure. Treatment with a mAb to alpha2-, alpha3-, and alpha6-integrin blocked wound repair in monolayers grown on collagen-IV but did not do so in monolayers grown either on laminin-1 or laminin-2. Inhibition was not due to cell detachment or apoptosis. These data demonstrate that integrins expressed by airway epithelial cells mediate wound closure on different constitutive ECM proteins. These data suggest that beta1-integrin subunit function is required to permit migration and spreading of epithelial cells, and that alpha-integrin subunits alone do not mediate migration of epithelial cells grown on either laminin-1 or laminin-2. These differences may become important if the matrix protein composition of airway basement membrane changes in disease states such as asthma.
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Affiliation(s)
- S R White
- Section of Pulmonary and Critical Care Medicine, Department of Medicine, Division of Biological Sciences, University of Chicago, Chicago, Illinois, USA.
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33
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Savla U, Waters CM. Mechanical strain inhibits repair of airway epithelium in vitro. THE AMERICAN JOURNAL OF PHYSIOLOGY 1998; 274:L883-92. [PMID: 9609726 DOI: 10.1152/ajplung.1998.274.6.l883] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The repair of airway epithelium after injury is crucial in restoring epithelial barrier integrity. Although the airway epithelium is stretched and compressed due to changes in both circumferential and longitudinal dimensions during respiration and may be overdistended during mechanical ventilation, the effect of cyclic strain on the repair of epithelial wounds is unknown. Human and cat airway epithelial cells were cultured on flexible membranes, wounded by scraping with a metal spatula, and subjected to cyclic strain using the Flexercell Strain Unit. Because the radial strain profile in the wells was nonuniform, we compared closure in regions of elongation and compression within the same well. Both cyclic elongation and cyclic compression significantly slowed repair, with compression having the greatest effect. This attenuation was dependent upon the time of relaxation (TR) during the cycle. When wells were stretched at 10 cycles/min (6 s/cycle) with TR = 5 s, wounds closed similarly to wounds in static wells, whereas in wells with TR = 1 s, significant inhibition was observed. As the TR during cycles increased (higher TR), wounds closed faster. We measured the effect of strain at various TRs on cell area and centroid-centroid distance (CD) as a measure of spreading and migration. While cell area and CD in static wells significantly increased over time, the area and CD of cells in the elongated regions did not change. Cells in compressed regions were significantly smaller, with significantly lower CD. Cell area and CD became progressively larger with increasing TR. These results suggest that mechanical strain inhibits epithelial repair.
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Affiliation(s)
- U Savla
- Department of Biomedical Engineering, Northwestern University, Chicago, Illinois 60611, USA
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Liu X, Umino T, Cano M, Ertl R, Veys T, Spurzem J, Romberger D, Rennard SI. Human bronchial epithelial cells can contract type I collagen gels. THE AMERICAN JOURNAL OF PHYSIOLOGY 1998; 274:L58-65. [PMID: 9458801 DOI: 10.1152/ajplung.1998.274.1.l58] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Fibroblasts can contract collagen gels, a process thought to be related to tissue remodeling. Because epithelial cells are also involved in repair responses, we postulated that human bronchial epithelial cells (HBECs) could cause contraction of collagen gels. To evaluate this, HBECs were plated on the top of native type I collagen gels and were incubated for 48 h. After this, the gels were released and floated in LHC-9-RPMI 1640 for varying times, and gel size was measured with an image analyzer. HBECs caused a marked contraction of the gels within 24 h; the area was reduced by 88 +/- 4% (P < 0.01). The degree of gel contraction was dependent on cell density; 12,500 cells/cm2 resulted in maximal contraction, and half-maximal contraction occurred at 7,500 cells/cm2. Contraction varied inversely with the collagen concentration (91 +/- 1% with 0.5 mg/ml collagen vs. 43 +/- 5% with 1.5 mg/ml collagen). In contrast to fibroblasts that contract gels most efficiently when cast into the gel, HBEC-mediated contraction was significantly (P < 0.01) more efficient when cells were on top of the gels rather than when cast into the gels. Anti-beta 1-integrin antibody blocked HBEC-mediated contraction by > 50%, whereas anti-alpha 2-, anti-alpha 3-, anti-alpha v-, anti-alpha v beta 5-, anti-beta 2-, or anti-beta 4-integrin antibody was without effect. The combination of anti-beta 1-integrin antibody and an anti-alpha-subfamily antibody completely blocked gel contraction induced by HBECs. In contrast, anti-cellular fibronectin antibody did not block HBEC-induced gel contraction, whereas it did block fibroblast-mediated gel contraction. In summary, human airway epithelial cells can contract type I collagen gels, a process that appears to require integrins but may not require fibronectin. This process may contribute to airway remodeling.
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Affiliation(s)
- X Liu
- Department of Internal Medicine, University of Nebraska Medical Center, Omaha 68198-5300, USA
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Knight D, McKay K, Wiggs B, Schellenberg RR, Bai T. Localization of leukaemia inhibitory factor to airway epithelium and its amplification of contractile responses to tachykinins. Br J Pharmacol 1997; 120:883-91. [PMID: 9138695 PMCID: PMC1564531 DOI: 10.1038/sj.bjp.0700965] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
1. In neural tissue, leukaemia inhibitory factor (LIF) is an important trophic cytokine. In this investigation, we determined if LIF was present in human and guinea-pig airways and examined the role of this cytokine in modulating airway responses to endogenous and exogenous tachykinins as well as muscarinic receptor and beta-adrenoceptor stimulation. 2. The presence of LIF in both human and guinea-pig airways was determined by immunohistochemistry. Guinea-pig tracheal explants were incubated in CRML-1066 media containing LIF (0.5, 5 or 50 ng ml-1) for periods of 3, 6, 24 and 48 h. Tracheal rings were then transferred to organ baths for measurement of isometric force in response to carbachol, capsaicin, the neurokinin1 (NK1) receptor agonist [Sar9,Met(O2)11]-substance P (SP), the NK2 receptor agonist neurokinin A (NKA) and isoprenaline. 3. LIF immunoreactivity was observed primarily in basally situated cells in the airway epithelium of both large and small airways. Less intense immunoreactivity was observed in vascular endothelium and glandular epithelium. 4. Treatment with LIF (0.5 ng ml-1) for 3 and 6 h significantly increased contractile responses to capsaicin by 42% and 43%, respectively, compared to time controls, whereas higher concentrations of LIF (5 and 50 ng ml-1) enhanced capsaicin-induced contractions only after 6 h. After 24 h, responses to capsaicin were not significantly different from 0 h control. Contractile responses to capsaicin following exposure to LIF at any concentration for 24 h were not significantly different from relative time control values. 5. Responses to [Sar9,Met(O2)11]-SP, carbachol and isoprenaline were not influenced by time in culture or by exposure to LIF for up to 48 h. Contractile responses induced by NKA were not influenced by 3 or 6 h exposure to LIF, but at 24 and 48 h the mean maximum contractile responses to NKA were significantly increased by 33% and 35%, respectively, compared to control. 6. These results demonstrate that LIF is present in guinea-pig and human airway epithelium, and modulates airway responses to tachykinins. In the acute setting LIF augments the capsaicin-induced release of endogenous tachykinins, whilst in the longer term (> 24 h), LIF increases airway smooth muscle responses to tachykinins via an NK2 receptor selective mechanism. We conclude that LIF may be an important effector molecule in the response of airways to injury or inflammation.
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Affiliation(s)
- D Knight
- University of British Columbia Pulmonary Research Laboratory, St Paul's Hospital, Vancouver, Canada
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Abstract
Asthma is classically defined in terms of reversible airflow obstruction. It is now recognized that histologic abnormalities, including inflammation, are a regular feature of asthma. In addition, alterations of the structural elements of the airway wall occur regularly in asthma. These alterations include a thickened basal lamina comprised of interstitial collagens as well as alterations in the mesenchymal cell population with an accumulation of myofibroblasts. It seems likely that these connective tissue alterations in the airway wall contribute to the physiologic abnormalities of asthma. While controversial, the long-term physiologic sequela of asthma may depend in large part on these changes. The biochemical and cellular basis that leads to these changes is, as yet, unknown, but recent studies suggest that a variety of cells in the airway, including inflammatory cells and the cells of the airway epithelium, may participate in regulating this response.
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Affiliation(s)
- S I Rennard
- University of Nebraska Medical Center, Pulmonary and Critical Care Medicine Section, Omaha 68198-5300, USA
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Ito H, Rennard SI, Spurzem JR. Mononuclear cell conditioned medium enhances bronchial epithelial cell migration but inhibits attachment to fibronectin. THE JOURNAL OF LABORATORY AND CLINICAL MEDICINE 1996; 127:494-503. [PMID: 8621987 DOI: 10.1016/s0022-2143(96)90067-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The attachment and migration of bronchial epithelial cells are important features in re-epithelialization after tissue injury. We hypothesized that inflammatory cytokines might alter bronchial epithelial cell attachment and migration. To test this hypothesis, we evaluated the effects of mononuclear cell conditioned medium (MNCCM) on attachment and migration of bronchial epithelial cells to fibronectin in vitro. MNCCM was prepared from bovine blood mononuclear cells that were stimulated with concanavalin A. MNCCM stimulated bronchial epithelial cell migration and spreading. Sephadex G-75 column chromatography of MNCCM found two peaks of migration-stimulatory activity. Activity in the higher molecular weight peak was partially inhibited by anti-tumor necrosis factor-alpha antibodies. Activity in the low-molecular-weight peak was lipid-extractable, suggesting the possibility that the activity was an arachidonate metabolite. We evaluated the effects of protein kinase C (PKC) inhibitors on enhancement of bronchial epithelial cell migration by MNCCM under the hypothesis that stimulated bronchial epithelial cell migration by MNCCM was elicited through PKC-dependent signaling pathways. PKC inhibitors, calphostin and H-7, inhibited the effect of MNCCM on bronchial epithelial cell migration. In addition, MNCCM stimulated PKC translocation and activity in these cells. Thus mononuclear cells produce inflammatory cytokines with important effects on bronchial epithelial cell migration and spreading. The stimulatory effect may be mediated in part through PKC signaling pathways.
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Affiliation(s)
- H Ito
- Research Service, Department of Veterans Affairs Medical Center, Omaha, NE USA
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Norlander T, Westrin KM, Fukami M, Stierna P, Carlsöö B. Experimentally induced polyps in the sinus mucosa: a structural analysis of the initial stages. Laryngoscope 1996; 106:196-203. [PMID: 8583853 DOI: 10.1097/00005537-199602000-00017] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
To document polyp formation in the sinus mucosa, the authors of this study subjected New Zealand white rabbits to different modes of manipulation intended to induce inflammation of the maxillary sinus. These manipulations included a combination of bacterial infection and mechanical trauma, the deposition of agarose into the sinus cavity, and the deposition of N-formyl-methionyl-leucyl-phenylalanine, a chemotactic peptide, into the sinus cavity. A majority of animals developed polyps, which were examined by light and electron microscopy. Polyp formation appears to involve epithelial disruption and the migration of immature branching epithelium. While part of the migrating epithelium eventually covers the mucosal defect, other branches spread into the underlying connective tissue, where intraepithelial microcavities with a differentiated, ciliated lining are formed. Fusing cavities separate the developing polyp body from the adjacent mucosa. With the described method, mucosal polyps can be induced with high reproducibility.
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Affiliation(s)
- T Norlander
- Department of Oto-Rhino-Laryngology, Huddinge University Hospital, Karolinska Institute, Sweden
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Erjefält JS, Erjefält I, Sundler F, Persson CG. In vivo restitution of airway epithelium. Cell Tissue Res 1995; 281:305-16. [PMID: 7648624 DOI: 10.1007/bf00583399] [Citation(s) in RCA: 140] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Epithelial shedding occurs in health and, extensively, in inflammatory airway diseases. This study describes deepithelialisation, reepithelialisation and associated events in guinea-pig trachea after shedding-like epithelial denudation in vivo. Mechanical deepithelialisation of an 800-microns wide tracheal zone was carried out using an orotracheal steel probe without bleeding or damage to the basement membrane. Reepithelialisation was studied by scanning- and transmission electron microscopy and light microscopy. Nerve fibres were examined by immunostaining. Cell proliferation was analysed by [3H]-thymidine autoradiography. Immediately after epithelial removal secretory and ciliated (and presumably basal) epithelial cells at the wound margin dedifferentiated, flattened and migrated rapidly (2-3 microns/min) over the denuded basement membrane. Within 8-15 h a new, flattened epithelium covered the entire deepithelialised zone. At 30 h a tight epithelial barrier was established and after 5 days the epithelium was fully redifferentiated. After completed migration an increased mitotic activity occurred in the epithelium and in fibroblasts/smooth muscle beneath the restitution zone. Reinnervating intraepithelial calcitonin gene-related peptide-containing nerve fibres appeared within 30 h. We conclude that (1) reproducible shedding-like denudation, without bleeding or damage to the basement membrane, can be produced in vivo; (2) secretory and ciliated cells participate in reepithelialisation by dedifferentiation and migration; (3) the initial migration is very fast in vivo; (4) shedding-like denudation may cause strong secretory and exudative responses as well as proliferation of epithelium, and fibroblasts/smooth muscle. Rapid restitution of airway epithelium may depend on contributions from the microcirculation and innervation.
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Affiliation(s)
- J S Erjefält
- Department of Medical Cell Research, University of Lund, Sweden
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Erjefält JS, Erjefält I, Sundler F, Persson CG. Effects of topical budesonide on epithelial restitution in vivo in guinea pig trachea. Thorax 1995; 50:785-92. [PMID: 7570417 PMCID: PMC474655 DOI: 10.1136/thx.50.7.785] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
BACKGROUND Continuous epithelial shedding and restitution processes may characterise the airways in diseases such as asthma. Epithelial restitution involves several humoral and cellular mechanisms that may potentially be affected by inhaled anti-asthma drugs. The present study examines the effect of a topical steroid on epithelial restitution in vivo in the guinea pig. METHODS The airway epithelium was mechanically removed from well defined areas of guinea pig trachea without surgery and without damage to the basement membrane or bleeding. An anti-inflammatory dose of budesonide (1 mg) was administered repeatedly to the tracheal surface by local superfusion 24 hours before, at (0 hours), and 24 hours after the denudation. Migration of epithelial cells, formation of a plasma exudation-derived gel, and appearance of luminal leucocytes were recorded by scanning electron microscopy. Cell proliferation was visualised by bromodeoxyuridine immunohistochemistry and tissue neutrophils and eosinophils by enzyme histochemistry. RESULTS Immediately after creation of the denuded zone ciliated and secretory cells on its border dedifferentiated, flattened out, and migrated speedily (mean (SE) 2.3 (0.3) micron/min) over the basement membrane. After 48 hours the entire denuded zone (800 microns wide) was covered by a tightly sealed epithelium; at this time increased proliferation was observed in new and old epithelium and subepithelial cells. Budesonide had no detectable effect on epithelial dedifferentiation, migration, sealing, or proliferation. Immediately after denudation and continuously during the migration phase plasma was extravasated creating a fibrinous gel rich in leucocytes, particularly neutrophils, over the denuded area. Budesonide had no effect on either the gel or the leucocyte density. CONCLUSIONS These observations suggest that topical glucocorticoids may not interfere with a fast and efficient restitution of the epithelium in the airways.
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Affiliation(s)
- J S Erjefält
- Department of Medical Cell Research, University of Lund, Sweden
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Rennard SI, Romberger DJ, Sisson JH, Von Essen SG, Rubinstein I, Robbins RA, Spurzem JR. Airway epithelial cells: functional roles in airway disease. Am J Respir Crit Care Med 1994; 150:S27-30. [PMID: 7952587 DOI: 10.1164/ajrccm/150.5_pt_2.s27] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Affiliation(s)
- S I Rennard
- Department of Internal Medicine, University of Nebraska, Omaha
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