1
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Varricchi G, Brightling CE, Grainge C, Lambrecht BN, Chanez P. Airway remodelling in asthma and the epithelium: on the edge of a new era. Eur Respir J 2024; 63:2301619. [PMID: 38609094 PMCID: PMC11024394 DOI: 10.1183/13993003.01619-2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Accepted: 02/15/2024] [Indexed: 04/14/2024]
Abstract
Asthma is a chronic, heterogeneous disease of the airways, often characterised by structural changes known collectively as airway remodelling. In response to environmental insults, including pathogens, allergens and pollutants, the epithelium can initiate remodelling via an inflammatory cascade involving a variety of mediators that have downstream effects on both structural and immune cells. These mediators include the epithelial cytokines thymic stromal lymphopoietin, interleukin (IL)-33 and IL-25, which facilitate airway remodelling through cross-talk between epithelial cells and fibroblasts, and between mast cells and airway smooth muscle cells, as well as through signalling with immune cells such as macrophages. The epithelium can also initiate airway remodelling independently of inflammation in response to the mechanical stress present during bronchoconstriction. Furthermore, genetic and epigenetic alterations to epithelial components are believed to influence remodelling. Here, we review recent advances in our understanding of the roles of the epithelium and epithelial cytokines in driving airway remodelling, facilitated by developments in genetic sequencing and imaging techniques. We also explore how new and existing therapeutics that target the epithelium and epithelial cytokines could modify airway remodelling.
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Affiliation(s)
- Gilda Varricchi
- Department of Translational Medical Sciences and Center for Basic and Clinical Immunology Research (CISI), School of Medicine, University of Naples Federico II, WAO Center of Excellence, Naples, Italy
- Institute of Experimental Endocrinology and Oncology (IEOS), National Research Council, Naples, Italy
- G. Varricchi and C.E. Brightling contributed equally
| | - Christopher E. Brightling
- Institute for Lung Health, NIHR Leicester Biomedical Research Centre, University of Leicester, Leicester, UK
- G. Varricchi and C.E. Brightling contributed equally
| | - Christopher Grainge
- School of Medicine and Public Health, University of Newcastle, Callaghan, Australia
| | - Bart N. Lambrecht
- Center for Inflammation Research, Laboratory of Immunoregulation and Mucosal Immunology, VIB Center for Inflammation Research, Ghent, Belgium
| | - Pascal Chanez
- Department of Respiratory Diseases, Aix-Marseille University, Marseille, France
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2
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Harvey BJ. Molecular mechanisms of dexamethasone actions in COVID-19: Ion channels and airway surface liquid dynamics. Steroids 2024; 202:109348. [PMID: 38049079 DOI: 10.1016/j.steroids.2023.109348] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Revised: 11/23/2023] [Accepted: 11/28/2023] [Indexed: 12/06/2023]
Abstract
The COVID-19 pandemic has been a global health crisis of unprecedented magnitude. In the battle against the SARS-CoV-2 coronavirus, dexamethasone, a widely used corticosteroid with potent anti-inflammatory properties, has emerged as a promising therapy in the fight against severe COVID-19. Dexamethasone is a synthetic glucocorticoid that exerts its therapeutic effects by suppressing the immune system and reducing inflammation. In the context of COVID-19, the severe form of the disease is often characterized by a hyperactive immune response, known as a cytokine storm. Dexamethasone anti-inflammatory properties make it a potent tool in modulating this exaggerated immune response. Lung inflammation may lead to excessive fluid accumulation in the airways which can reduce gas exchange and mucociliary clearance. Pulmonary oedema and flooding of the airways are hallmarks of severe COVID-19 lung disease. The volume of airway surface liquid is determined by a delicate balance of salt and water secretion and absorption across the airway epithelium. In addition to its anti-inflammatory actions, dexamethasone modulates the activity of ion channels which regulate electrolyte and water transport across the airway epithelium. The observations of dexamethasone activation of sodium ion absorption via ENaC Na+ channels and inhibition of chloride ion secretion via CFTR Cl- channels to decrease airway surface liquid volume indicate a novel therapeutic action of the glucocorticoid to reverse airway flooding. This brief review delves into the early non-genomic and late genomic signaling mechanisms of dexamethasone regulation of ion channels and airway surface liquid dynamics, shedding light on the molecular mechanisms underpinning the action of the glucocorticoid in managing COVID-19.
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Affiliation(s)
- Brian J Harvey
- Faculty of Medicine, Royal College of Surgeons in Ireland, RCSI University of Medicine and Health Sciences, Dublin 2, Ireland; Centro de Estudios Cientificos, Valdivia, Chile.
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3
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Kawasumi M, Araki Y, Mito M, Fukuhara K, Zaitsu J, Kuraoka K, Senoo T. A Case of Invasive Mucinous Adenocarcinoma with Acute Respiratory Distress Syndrome Diagnosed by Autopsy Findings. Intern Med 2022. [PMID: 36418103 PMCID: PMC10400389 DOI: 10.2169/internalmedicine.0926-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
We herein report a fatal case of invasive mucinous adenocarcinoma (IMA) with acute respiratory distress syndrome (ARDS) diagnosed based on autopsy findings. A 76-year-old man presented with severe respiratory discomfort on admission. Computed tomography (CT) revealed a peripheral distribution of consolidation. Although his respiratory status improved after steroid therapy, re-exacerbation occurred, and the patient died on day 131. A bronchoscopic lung biopsy had shown organizing pneumonia, but a post-mortem examination surprisingly revealed IMA with organizing pneumonia. IMA presenting with ARDS as the first symptom is extremely rare.
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Affiliation(s)
- Muneo Kawasumi
- The Clinical Training Center, National Hospital Organization, Kure Medical Center and Chugoku Cancer Center, Japan
| | - Yusuke Araki
- Department of Respiratory Medicine, National Hospital Organization, Kure Medical Center and Chugoku Cancer Center, Japan
| | - Mineyo Mito
- Department of Respiratory Medicine, National Hospital Organization, Kure Medical Center and Chugoku Cancer Center, Japan
| | - Kazuhide Fukuhara
- Department of Respiratory Medicine, National Hospital Organization, Kure Medical Center and Chugoku Cancer Center, Japan
| | - Junichi Zaitsu
- Department of Diagnostic Pathology, National Hospital Organization, Kure Medical Center and Chugoku Cancer Center, Japan
| | - Kazuya Kuraoka
- Department of Diagnostic Pathology, National Hospital Organization, Kure Medical Center and Chugoku Cancer Center, Japan
| | - Tadashi Senoo
- Department of Respiratory Medicine, National Hospital Organization, Kure Medical Center and Chugoku Cancer Center, Japan
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4
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Carlier FM, de Fays C, Pilette C. Epithelial Barrier Dysfunction in Chronic Respiratory Diseases. Front Physiol 2021; 12:691227. [PMID: 34248677 PMCID: PMC8264588 DOI: 10.3389/fphys.2021.691227] [Citation(s) in RCA: 57] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Accepted: 05/20/2021] [Indexed: 12/15/2022] Open
Abstract
Mucosal surfaces are lined by epithelial cells, which provide a complex and adaptive module that ensures first-line defense against external toxics, irritants, antigens, and pathogens. The underlying mechanisms of host protection encompass multiple physical, chemical, and immune pathways. In the lung, inhaled agents continually challenge the airway epithelial barrier, which is altered in chronic diseases such as chronic obstructive pulmonary disease, asthma, cystic fibrosis, or pulmonary fibrosis. In this review, we describe the epithelial barrier abnormalities that are observed in such disorders and summarize current knowledge on the mechanisms driving impaired barrier function, which could represent targets of future therapeutic approaches.
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Affiliation(s)
- François M. Carlier
- Pole of Pneumology, ENT, and Dermatology, Institute of Experimental and Clinical Research, Université catholique de Louvain, Brussels, Belgium
- Department of Pneumology and Lung Transplant, Centre Hospitalier Universitaire UCL Namur, Yvoir, Belgium
| | - Charlotte de Fays
- Pole of Pneumology, ENT, and Dermatology, Institute of Experimental and Clinical Research, Université catholique de Louvain, Brussels, Belgium
| | - Charles Pilette
- Pole of Pneumology, ENT, and Dermatology, Institute of Experimental and Clinical Research, Université catholique de Louvain, Brussels, Belgium
- Department of Pneumology, Cliniques universitaires St-Luc, Brussels, Belgium
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5
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Ishahak M, Hill J, Amin Q, Wubker L, Hernandez A, Mitrofanova A, Sloan A, Fornoni A, Agarwal A. Modular Microphysiological System for Modeling of Biologic Barrier Function. Front Bioeng Biotechnol 2020; 8:581163. [PMID: 33304889 PMCID: PMC7693638 DOI: 10.3389/fbioe.2020.581163] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Accepted: 10/21/2020] [Indexed: 12/13/2022] Open
Abstract
Microphysiological systems, also known as organs-on-chips, are microfluidic devices designed to model human physiology in vitro. Polydimethylsiloxane (PDMS) is the most widely used material for organs-on-chips due to established microfabrication methods, and properties that make it suitable for biological applications such as low cytotoxicity, optical transparency, gas permeability. However, absorption of small molecules and leaching of uncrosslinked oligomers might hinder the adoption of PDMS-based organs-on-chips for drug discovery assays. Here, we have engineered a modular, PDMS-free microphysiological system that is capable of recapitulating biologic barrier functions commonly demonstrated in PDMS-based devices. Our microphysiological system is comprised of a microfluidic chip to house cell cultures and pneumatic microfluidic pumps to drive flow with programmable pressure and shear stress. The modular architecture and programmable pumps enabled us to model multiple in vivo microenvironments. First, we demonstrate the ability to generate cyclic strain on the culture membrane and establish a model of the alveolar air-liquid interface. Next, we utilized three-dimensional finite element analysis modeling to characterize the fluid dynamics within the device and develop a model of the pressure-driven filtration that occurs at the glomerular filtration barrier. Finally, we demonstrate that our model can be used to recapitulate sphingolipid induced kidney injury. Together, our results demonstrate that a multifunctional and modular microphysiological system can be deployed without the use of PDMS. Further, the bio-inert plastic used in our microfluidic device is amenable to various established, high-throughput manufacturing techniques, such as injection molding. As a result, the development plastic organs-on-chips provides an avenue to meet the increasing demand for organ-on-chip technology.
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Affiliation(s)
- Matthew Ishahak
- Department of Biomedical Engineering, University of Miami, Coral Gables, FL, United States
| | - Jordan Hill
- Department of Biomedical Engineering, University of Miami, Coral Gables, FL, United States
| | - Quratulain Amin
- Department of Biomedical Engineering, University of Miami, Coral Gables, FL, United States
| | - Laura Wubker
- Department of Biomedical Engineering, University of Miami, Coral Gables, FL, United States
| | - Adiel Hernandez
- Department of Biomedical Engineering, University of Miami, Coral Gables, FL, United States
| | - Alla Mitrofanova
- Katz Family Division of Nephrology and Hypertension, Department of Medicine, Peggy and Harold Katz Family Drug Discovery Center, University of Miami Miller School of Medicine, Miami, FL, United States
| | - Alexis Sloan
- Katz Family Division of Nephrology and Hypertension, Department of Medicine, Peggy and Harold Katz Family Drug Discovery Center, University of Miami Miller School of Medicine, Miami, FL, United States
| | - Alessia Fornoni
- Department of Biochemistry & Molecular Biology, DJTMF Biomedical Nanotechnology Institute, University of Miami Miller School of Medicine, Miami, FL, United States.,Katz Family Division of Nephrology and Hypertension, Department of Medicine, Peggy and Harold Katz Family Drug Discovery Center, University of Miami Miller School of Medicine, Miami, FL, United States
| | - Ashutosh Agarwal
- Department of Biomedical Engineering, University of Miami, Coral Gables, FL, United States.,Department of Biochemistry & Molecular Biology, DJTMF Biomedical Nanotechnology Institute, University of Miami Miller School of Medicine, Miami, FL, United States
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Kato K, Chang EH, Chen Y, Lu W, Kim MM, Niihori M, Hecker L, Kim KC. MUC1 contributes to goblet cell metaplasia and MUC5AC expression in response to cigarette smoke in vivo. Am J Physiol Lung Cell Mol Physiol 2020; 319:L82-L90. [PMID: 32401676 DOI: 10.1152/ajplung.00049.2019] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Goblet cell metaplasia (GCM) and mucin overproduction are a hallmark of chronic rhinosinusitis (CRS) and chronic obstructive pulmonary disease (COPD). In the airways, cigarette smoke (CS) induces activation of the epidermal growth factor receptor (EGFR) leading to GCM and overexpression of the gel-forming mucin MUC5AC. Although previous studies have demonstrated that a membrane-bound mucin, MUC1, modulates the activation of CS-induced EGFR, the role of MUC1 in CS-induced GCM and mucin overproduction has not been explored. In response to CS exposure, wild-type (WT) rats displayed Muc1 translocation from the apical surface of airway epithelium to the intracellular compartment of hyperplastic intermediate cells, EGFR phosphorylation, GCM, and Muc5ac overproduction. Similarly, human CRS sinonasal tissues demonstrated hyperplasia of intermediate cells enriched with MUC1 in the intracellular compartment, which was accompanied by GCM and increased MUC5AC expression. To further evaluate the role of Muc1 in vivo, a Muc1 knockout (KO) rat (MUC in humans and Muc in animals) was developed. In contrast to WT littermates, Muc1-KO rats exhibited no activation of EGFR, and were protected from GCM and Muc5ac overproduction. Genetic knockdown of MUC1 in human lung or Muc1 knockout in primary rat airway epithelial cells led to significantly diminished EGF-induced MUC5AC production. Together, these findings suggest that MUC1-dependent EGFR activation mediates CS-induced GCM and mucin overproduction. Strategies designed to suppress MUC1-dependent EGFR activation may provide a novel therapeutic approach for treating mucin hypersecretion in CRS and COPD.
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Affiliation(s)
- Kosuke Kato
- Department of Medicine, Division of Pulmonary, Allergy, Critical Care and Sleep Medicine, University of Arizona College of Medicine, Tucson, Arizona
| | - Eugene H Chang
- Department of Otolaryngology, University of Arizona College of Medicine, Tucson, Arizona
| | - Yin Chen
- Department of Pharmacology and Toxicology, University of Arizona College of Pharmacy, Tucson, Arizona
| | - Wenju Lu
- Department of Medicine, National Key Laboratory of Respiratory Disease, Guangzhou Medical University, Guangzhou, China
| | - Marianne M Kim
- Department of Otolaryngology, University of Arizona College of Medicine, Tucson, Arizona
| | - Maki Niihori
- Department of Otolaryngology, University of Arizona College of Medicine, Tucson, Arizona
| | - Louise Hecker
- Department of Medicine, Division of Pulmonary, Allergy, Critical Care and Sleep Medicine, University of Arizona College of Medicine, Tucson, Arizona.,Southern Arizona Veterans Affairs Health Care System, Tucson, Arizona
| | - Kwang Chul Kim
- Department of Otolaryngology, University of Arizona College of Medicine, Tucson, Arizona
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7
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Garić D, De Sanctis JB, Dumut DC, Shah J, Peña MJ, Youssef M, Petrof BJ, Kopriva F, Hanrahan JW, Hajduch M, Radzioch D. Fenretinide favorably affects mucins (MUC5AC/MUC5B) and fatty acid imbalance in a manner mimicking CFTR-induced correction. Biochim Biophys Acta Mol Cell Biol Lipids 2019; 1865:158538. [PMID: 31678518 DOI: 10.1016/j.bbalip.2019.158538] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2019] [Revised: 09/28/2019] [Accepted: 10/03/2019] [Indexed: 02/07/2023]
Abstract
Cystic fibrosis (CF) is the most common genetic disease in Caucasians. CF is manifested by abnormal accumulation of mucus in the lungs, which serves as fertile ground for the growth of microorganisms leading to recurrent infections and ultimately, lung failure. Mucus in CF patients consists of DNA from dead neutrophils as well as mucins produced by goblet cells. MUC5AC mucin leads to pathological plugging of the airways whereas MUC5B has a protective role against bacterial infection. Therefore, decreasing the level of MUC5AC while maintaining MUC5B intact would in principle be a desirable mucoregulatory treatment outcome. Fenretinide prevented the lipopolysaccharide-induced increase of MUC5AC gene expression, without affecting the level of MUC5B, in a lung goblet cell line. Additionally, fenretinide treatment reversed the pro-inflammatory imbalance of fatty acids by increasing docosahexaenoic acid and decreasing the levels of arachidonic acid in a lung epithelial cell line and primary leukocytes derived from CF patients. Furthermore, for the first time we also demonstrate the effect of fenretinide on multiple unsaturated fatty acids, as well as differential effects on the levels of long- compared to very-long-chain saturated fatty acids which are important substrates of complex phospholipids. Finally, we demonstrate that pre-treating mice with fenretinide in a chronic model of P. aeruginosa lung infection efficiently decreases the accumulation of mucus. These findings suggest that fenretinide may offer a new approach to therapeutic modulation of pathological mucus production in CF.
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Affiliation(s)
- Dušan Garić
- Department of Human Genetics, McGill University, Montreal, Quebec, Canada; Program in Infectious Diseases and Immunity in Global Health, McGill University Health Center, Montreal, Quebec, Canada
| | - Juan B De Sanctis
- Institute of Molecular and Translational Medicine, Faculty of Medicine and Dentistry, Palacky University, Olomouc, Czech Republic; Institute of Immunology, Faculty of Medicine, Universidad Central de Venezuela, Bolivarian Republic of Venezuela
| | - Daciana Catalina Dumut
- Department of Medicine, Division of Experimental Medicine, McGill University, Montreal, Quebec, Canada; Program in Infectious Diseases and Immunity in Global Health, McGill University Health Center, Montreal, Quebec, Canada
| | - Juhi Shah
- Department of Pharmacology and Therapeutics, McGill University, Montreal, Quebec, Canada; Program in Infectious Diseases and Immunity in Global Health, McGill University Health Center, Montreal, Quebec, Canada
| | - Maria Johanna Peña
- Institute of Immunology, Faculty of Medicine, Universidad Central de Venezuela, Bolivarian Republic of Venezuela
| | - Mina Youssef
- Department of Human Genetics, McGill University, Montreal, Quebec, Canada; Program in Infectious Diseases and Immunity in Global Health, McGill University Health Center, Montreal, Quebec, Canada
| | - Basil J Petrof
- Meakins-Christie Laboratories, Translational Research in Respiratory Diseases Program, Department of Medicine, McGill University Health Centre, Montreal, Quebec, Canada
| | - Francisek Kopriva
- Institute of Molecular and Translational Medicine, Faculty of Medicine and Dentistry, Palacky University, Olomouc, Czech Republic
| | - John W Hanrahan
- Department of Biochemistry, McGill University, Montreal, Quebec, Canada
| | - Marian Hajduch
- Institute of Molecular and Translational Medicine, Faculty of Medicine and Dentistry, Palacky University, Olomouc, Czech Republic
| | - Danuta Radzioch
- Department of Human Genetics, McGill University, Montreal, Quebec, Canada; Institute of Molecular and Translational Medicine, Faculty of Medicine and Dentistry, Palacky University, Olomouc, Czech Republic; Department of Medicine, Division of Experimental Medicine, McGill University, Montreal, Quebec, Canada; Program in Infectious Diseases and Immunity in Global Health, McGill University Health Center, Montreal, Quebec, Canada.
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8
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An JY, Ahn C, Kang HY, Jeung EB. Inhibition of mucin secretion via glucocorticoid-induced regulation of calcium-related proteins in mouse lung. Am J Physiol Lung Cell Mol Physiol 2018; 314:L956-L966. [DOI: 10.1152/ajplung.00417.2017] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Calcium is important for physiological functioning in many tissues and is essential in mucus secretion and muscle contraction. Intracellular concentrations of calcium are regulated by calcium-related proteins, such as transient receptor potential cation channel subfamily V member 4 (TRPV 4), TRPV6, Calbindin-D9k (CaBP-9k), sodium-calcium exchanger (NCX1), and plasma membrane Ca2+ ATPase 1 (PMCA1). In this study, the relationship between secretion of pulmonary mucus and calcium regulation was investigated. To confirm the effect of steroid hormones, immature mice were injected with estrogen (E2) or progesterone (P4), and mature mice were injected with dexamethasone (DEX). Subsequently, the location and expression of TRPV4, TRPV6, CaBP-9k, NCX1, and PMCA1 in lung tissue were examined. Periodic acid-Schiff staining was performed to investigate functional aspects of the protein expression. There were no significant differences in calcium-related gene expression in E2- and P4-treated mice, but TRPV4, NCX1, and PMCA1 were increased in DEX-treated mice and were recovered by RU486 treatment. DEX induces the expression of calcium-related proteins through the glucocorticoid receptor-mediated pathway and may involve decreased mucin secretion in the bronchiole. TRPV4, TRPV6, CaBP-9k, NCX1, and PMCA1 were specifically expressed in Clara and alveolar type 2 cells of mouse lung. CC10, a marker of Clara cells, was decreased by DEX. In addition, mucin secretion, which is a functional aspect of this cell, was also decreased by DEX treatment. Control of calcium-related gene expression may affect the control of mucus secretion in the lung. Such a control mechanism can form the basis of studies into diseases such as inflammation attributable to mucus secretion abnormalities, coughing, and respiratory disorders and distress.
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Affiliation(s)
- Jin Yong An
- Laboratory of Veterinary Biochemistry and Molecular Biology, College of Veterinary Medicine, Chungbuk National University, Cheongju, Chungbuk, Republic of Korea
| | - Changhwan Ahn
- Laboratory of Veterinary Biochemistry and Molecular Biology, College of Veterinary Medicine, Chungbuk National University, Cheongju, Chungbuk, Republic of Korea
| | - Hee Young Kang
- Laboratory of Veterinary Biochemistry and Molecular Biology, College of Veterinary Medicine, Chungbuk National University, Cheongju, Chungbuk, Republic of Korea
- Immunotherapy Convergence Research Center, Korea Research Institute of Bioscience and Biotechnology, Yuseong-gu, Daejeon, Republic of Korea
| | - Eui-Bae Jeung
- Laboratory of Veterinary Biochemistry and Molecular Biology, College of Veterinary Medicine, Chungbuk National University, Cheongju, Chungbuk, Republic of Korea
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9
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Ohneck EJ, Arivett BA, Fiester SE, Wood CR, Metz ML, Simeone GM, Actis LA. Mucin acts as a nutrient source and a signal for the differential expression of genes coding for cellular processes and virulence factors in Acinetobacter baumannii. PLoS One 2018; 13:e0190599. [PMID: 29309434 PMCID: PMC5757984 DOI: 10.1371/journal.pone.0190599] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2017] [Accepted: 12/18/2017] [Indexed: 12/27/2022] Open
Abstract
The capacity of Acinetobacter baumannii to persist and cause infections depends on its interaction with abiotic and biotic surfaces, including those found on medical devices and host mucosal surfaces. However, the extracellular stimuli affecting these interactions are poorly understood. Based on our previous observations, we hypothesized that mucin, a glycoprotein secreted by lung epithelial cells, particularly during respiratory infections, significantly alters A. baumannii's physiology and its interaction with the surrounding environment. Biofilm, virulence and growth assays showed that mucin enhances the interaction of A. baumannii ATCC 19606T with abiotic and biotic surfaces and its cytolytic activity against epithelial cells while serving as a nutrient source. The global effect of mucin on the physiology and virulence of this pathogen is supported by RNA-Seq data showing that its presence in a low nutrient medium results in the differential transcription of 427 predicted protein-coding genes. The reduced expression of ion acquisition genes and the increased transcription of genes coding for energy production together with the detection of mucin degradation indicate that this host glycoprotein is a nutrient source. The increased expression of genes coding for adherence and biofilm biogenesis on abiotic and biotic surfaces, the degradation of phenylacetic acid and the production of an active type VI secretion system further supports the role mucin plays in virulence. Taken together, our observations indicate that A. baumannii recognizes mucin as an environmental signal, which triggers a response cascade that allows this pathogen to acquire critical nutrients and promotes host-pathogen interactions that play a role in the pathogenesis of bacterial infections.
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Affiliation(s)
- Emily J. Ohneck
- Department of Microbiology, Miami University, Oxford, OH, United States of America
| | - Brock A. Arivett
- Department of Microbiology, Miami University, Oxford, OH, United States of America
| | - Steven E. Fiester
- Department of Microbiology, Miami University, Oxford, OH, United States of America
| | - Cecily R. Wood
- Department of Microbiology, Miami University, Oxford, OH, United States of America
| | - Maeva L. Metz
- Department of Microbiology, Miami University, Oxford, OH, United States of America
| | - Gabriella M. Simeone
- Department of Microbiology, Miami University, Oxford, OH, United States of America
| | - Luis A. Actis
- Department of Microbiology, Miami University, Oxford, OH, United States of America
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10
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Kamei S, Fujikawa H, Nohara H, Ueno-Shuto K, Maruta K, Nakashima R, Kawakami T, Matsumoto C, Sakaguchi Y, Ono T, Suico MA, Boucher RC, Gruenert DC, Takeo T, Nakagata N, Li JD, Kai H, Shuto T. Zinc Deficiency via a Splice Switch in Zinc Importer ZIP2/SLC39A2 Causes Cystic Fibrosis-Associated MUC5AC Hypersecretion in Airway Epithelial Cells. EBioMedicine 2017; 27:304-316. [PMID: 29289532 PMCID: PMC5828551 DOI: 10.1016/j.ebiom.2017.12.025] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2017] [Revised: 12/15/2017] [Accepted: 12/19/2017] [Indexed: 01/02/2023] Open
Abstract
Airway mucus hyperproduction and fluid imbalance are important hallmarks of cystic fibrosis (CF), the most common life-shortening genetic disorder in Caucasians. Dysregulated expression and/or function of airway ion transporters, including cystic fibrosis transmembrane conductance regulator (CFTR) and epithelial sodium channel (ENaC), have been implicated as causes of CF-associated mucus hypersecretory phenotype. However, the contributory roles of other substances and transporters in the regulation of CF airway pathogenesis remain unelucidated. Here, we identified a novel connection between CFTR/ENaC expression and the intracellular Zn2 + concentration in the regulation of MUC5AC, a major secreted mucin that is highly expressed in CF airway. CFTR-defective and ENaC-hyperactive airway epithelial cells specifically and highly expressed a unique, alternative splice isoform of the zinc importer ZIP2/SLC39A2 (ΔC-ZIP2), which lacks the C-terminal domain. Importantly, ΔC-ZIP2 levels correlated inversely with wild-type ZIP2 and intracellular Zn2 + levels. Moreover, the splice switch to ΔC-ZIP2 as well as decreased expression of other ZIPs caused zinc deficiency, which is sufficient for induction of MUC5AC; while ΔC-ZIP2 expression per se induced ENaC expression and function. Thus, our findings demonstrate that the novel splicing switch contributes to CF lung pathology via the novel interplay of CFTR, ENaC, and ZIP2 transporters. Zinc deficiency is a common feature in both CFTR-defective (CF) and ENaC-hyperactive (CF-like) airway epithelial cells. A splice switch from WT-ZIP2 to ΔC-ZIP2 as well as other ZIPs down-regulation caused zinc deficiency in CF and CF-like cells. Lower intracellular Zn2 + levels contributed to CF-associated MUC5AC hypersecretion in airway epithelial cells.
The role of zinc in the pathogenesis of CF lung disease is not well understood. We utilized human CF patient-derived cell lines and primary cells as well as murine CF model, and identified zinc deficiency as a common characteristic in CF models. Down-regulation of several zinc importers (ZIPs) in CF cells caused zinc deficiency, which is sufficient for induction of MUC5AC, a major secreted mucin that exacerbates CF pathogenesis. Especially, strong contribution of ΔC-ZIP2, a novel ZIP2 splice isoform, in the regulation of CF-associated MUC5AC hypersecretion was clearly demonstrated. The study refined the importance of zinc in airway homeostasis.
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Affiliation(s)
- Shunsuke Kamei
- Department of Molecular Medicine, Graduate School of Pharmaceutical Sciences, Kumamoto University, 5-1 Oe-Honmachi, Chuo-ku, Kumamoto 862-0973, Japan; Program for Leading Graduate Schools "HIGO (Health life science: Interdisciplinary and Glocal Oriented) Program", Kumamoto University, 5-1 Oe-Honmachi, Chuo-ku, Kumamoto 862-0973, Japan
| | - Haruka Fujikawa
- Department of Molecular Medicine, Graduate School of Pharmaceutical Sciences, Kumamoto University, 5-1 Oe-Honmachi, Chuo-ku, Kumamoto 862-0973, Japan; Program for Leading Graduate Schools "HIGO (Health life science: Interdisciplinary and Glocal Oriented) Program", Kumamoto University, 5-1 Oe-Honmachi, Chuo-ku, Kumamoto 862-0973, Japan
| | - Hirofumi Nohara
- Department of Molecular Medicine, Graduate School of Pharmaceutical Sciences, Kumamoto University, 5-1 Oe-Honmachi, Chuo-ku, Kumamoto 862-0973, Japan; Program for Leading Graduate Schools "HIGO (Health life science: Interdisciplinary and Glocal Oriented) Program", Kumamoto University, 5-1 Oe-Honmachi, Chuo-ku, Kumamoto 862-0973, Japan
| | - Keiko Ueno-Shuto
- Laboratory of Pharmacology, Division of Life Science, Faculty of Pharmaceutical Sciences, Sojo University, 4-22-1 Ikeda, Nishi-ku, Kumamoto 860-0082, Japan
| | - Kasumi Maruta
- Department of Molecular Medicine, Graduate School of Pharmaceutical Sciences, Kumamoto University, 5-1 Oe-Honmachi, Chuo-ku, Kumamoto 862-0973, Japan
| | - Ryunosuke Nakashima
- Department of Molecular Medicine, Graduate School of Pharmaceutical Sciences, Kumamoto University, 5-1 Oe-Honmachi, Chuo-ku, Kumamoto 862-0973, Japan
| | - Taisei Kawakami
- Department of Molecular Medicine, Graduate School of Pharmaceutical Sciences, Kumamoto University, 5-1 Oe-Honmachi, Chuo-ku, Kumamoto 862-0973, Japan
| | - Chizuru Matsumoto
- Department of Molecular Medicine, Graduate School of Pharmaceutical Sciences, Kumamoto University, 5-1 Oe-Honmachi, Chuo-ku, Kumamoto 862-0973, Japan
| | - Yuki Sakaguchi
- Department of Molecular Medicine, Graduate School of Pharmaceutical Sciences, Kumamoto University, 5-1 Oe-Honmachi, Chuo-ku, Kumamoto 862-0973, Japan
| | - Tomomi Ono
- Department of Molecular Medicine, Graduate School of Pharmaceutical Sciences, Kumamoto University, 5-1 Oe-Honmachi, Chuo-ku, Kumamoto 862-0973, Japan
| | - Mary Ann Suico
- Department of Molecular Medicine, Graduate School of Pharmaceutical Sciences, Kumamoto University, 5-1 Oe-Honmachi, Chuo-ku, Kumamoto 862-0973, Japan
| | - Richard C Boucher
- Marsico Lung Institute, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Dieter C Gruenert
- Head and Neck Stem Cell Lab, University of California, San Francisco, 2340 Sutter St, Box 1330, N331, San Francisco, CA 94115, USA
| | - Toru Takeo
- Division of Reproductive Engineering, Center for Animal Resources and Development (CARD), Kumamoto University, 2-2-1 Honjo, Chuo-ku, Kumamoto 860-0811, Japan
| | - Naomi Nakagata
- Division of Reproductive Engineering, Center for Animal Resources and Development (CARD), Kumamoto University, 2-2-1 Honjo, Chuo-ku, Kumamoto 860-0811, Japan
| | - Jian-Dong Li
- Center for Inflammation, Immunity & Infection, Institute for Biomedical Sciences, Georgia State University, 714 Petit Science Center, 100 Piedmont Ave SE, Atlanta GA30303, USA
| | - Hirofumi Kai
- Department of Molecular Medicine, Graduate School of Pharmaceutical Sciences, Kumamoto University, 5-1 Oe-Honmachi, Chuo-ku, Kumamoto 862-0973, Japan.
| | - Tsuyoshi Shuto
- Department of Molecular Medicine, Graduate School of Pharmaceutical Sciences, Kumamoto University, 5-1 Oe-Honmachi, Chuo-ku, Kumamoto 862-0973, Japan.
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11
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Uchino Y, Woodward AM, Argüeso P. Differential effect of rebamipide on transmembrane mucin biosynthesis in stratified ocular surface epithelial cells. Exp Eye Res 2016; 153:1-7. [PMID: 27725198 DOI: 10.1016/j.exer.2016.10.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2016] [Revised: 09/29/2016] [Accepted: 10/06/2016] [Indexed: 10/20/2022]
Abstract
Mucins are a group of highly glycosylated glycoproteins responsible for the protection of wet-surfaced epithelia. Recent data indicate that transmembrane mucins differ in their contribution to the protective function of the ocular surface, with MUC16 being the most effective barrier on the apical surface glycocalyx. Here, we investigated the role of the mucoprotective drug rebamipide in the regulation of transmembrane mucin biosynthesis using stratified cultures of human corneal and conjunctival epithelial cells. We find that the addition of rebamipide to corneal, but not conjunctival, epithelial cells increased MUC16 protein biosynthesis. Rebamipide did not affect the levels of MUC1, 4 and 20 compared to control. In these experiments, rebamipide had no effect on the expression levels of Notch intracellular domains, suggesting that the rebamipide-induced increase in MUC16 biosynthesis in differentiated corneal cultures is not regulated by Notch signaling. Overall these findings indicate that rebamipide induces the differential upregulation of MUC16 in stratified cultures of human corneal epithelial cells, which may have implications to the proper restoration of barrier function in ocular surface disease.
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Affiliation(s)
- Yuichi Uchino
- Schepens Eye Research Institute and Massachusetts Eye and Ear, Department of Ophthalmology, Harvard Medical School, Boston, MA 02114, USA
| | - Ashley M Woodward
- Schepens Eye Research Institute and Massachusetts Eye and Ear, Department of Ophthalmology, Harvard Medical School, Boston, MA 02114, USA
| | - Pablo Argüeso
- Schepens Eye Research Institute and Massachusetts Eye and Ear, Department of Ophthalmology, Harvard Medical School, Boston, MA 02114, USA.
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12
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Poletti D, Iannini V, Casolari P, Contoli M, Papi A, Kirkham P, Hansel TT, Chung KF, Barnes PJ, Pastore A, Pelucchi S, Adcock IM, Caramori G. Nasal inflammation and its response to local glucocorticoid regular treatment in patients with persistent non-allergic rhinitis: a pilot study. JOURNAL OF INFLAMMATION-LONDON 2016; 13:26. [PMID: 27493587 PMCID: PMC4973027 DOI: 10.1186/s12950-016-0134-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Accepted: 07/29/2016] [Indexed: 11/10/2022]
Abstract
BACKGROUND The pathogenesis of non-allergic rhinitis (NAR) is still largely unknown. Furthermore, it is unclear whether there is a correlation between the effect of nasal glucocorticoids on nasal inflammation and on nasal symptoms and quality of life. METHODS In this pilot study we recruited 12 healthy subjects and 24 patients with recently diagnosed persistent NAR [12 untreated and 12 under regular treatment with nasal fluticasone furoate (two sprays of 27.5 μg each in each nostril once daily, total daily dose = 110 μg) for at least 20 days]. Each subject filled a mini rhinoconjunctivitis quality of life questionnaire (mini RQLQ). Nasal scrapings were obtained from each subject and used to prepare slides for Diff-Quik and immunocytochemical staining for inflammatory and epithelial cells count, MUC5AC expression and the general pro-inflammatory transcription factor nuclear factor kB (NF-kB) activation. RESULTS The nasal score of the mini RQLQ, the number of nasal inflammatory cells (neutrophils, eosinophils) and the number of goblet cells are significantly higher in untreated patients with persistent NAR compared with control subjects and treated NAR patients. The percentage of MUC5AC+ nasal epithelial cells is significantly increased in untreated patients with persistent NAR compared with the control subjects (41.8 ± 6.4 vs 22.3 ± 4.8, respectively; p = 0.0403) without significant differences between control subjects and patients with persistent NAR on regular fluticasone furoate treatment (33.9 ± 5.0 %; p = 0.0604) nor between the 2 groups of persistent NAR subjects (p = 0.3260). The number of cytosolic and/or nuclear p65+ nasal epithelial and inflammatory cells was not significantly different between the three groups. CONCLUSIONS Patients with persistent untreated NAR, compared with normal control subjects and patients with persistent NAR under regular treatment with nasal fluticasone furoate by at least 20 days, have more nasal symptoms, worst quality of life and an increased number of nasal inflammatory cells (neutrophils, eosinophils), goblet cells and MUC5AC+ nasal epithelial cells. This nasal inflammation seems unrelated to NF-kB activation.
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Affiliation(s)
- Donatella Poletti
- ORL, Azienda USL Ferrara, Italy, Sezione di Scienze Otorinolaringoiatriche e Fisica Medica, Departimento di Scienze Biomediche e Chirurgico Specialistiche, University of Ferrara, Ferrara, Italy
| | - Valeria Iannini
- Sezione di Scienze Otorinolaringoiatriche e Fisica Medica, Dipartimento di Scienze Biomediche e Chirurgico Specialistiche, University of Ferrara, Ferrara, Italy
| | - Paolo Casolari
- Centro Interdipartimentale per lo Studio delle Malattie Infiammatorie delle Vie Aeree e Patologie Fumo-correlate (CEMICEF), Dipartimento di Scienze Mediche, Sezione di Medicina Interna e Cardiorespiratoria, Università di Ferrara, Via Ludovico Ariosto 35, 44121 Ferrara, Italy
| | - Marco Contoli
- Centro Interdipartimentale per lo Studio delle Malattie Infiammatorie delle Vie Aeree e Patologie Fumo-correlate (CEMICEF), Dipartimento di Scienze Mediche, Sezione di Medicina Interna e Cardiorespiratoria, Università di Ferrara, Via Ludovico Ariosto 35, 44121 Ferrara, Italy
| | - Alberto Papi
- Centro Interdipartimentale per lo Studio delle Malattie Infiammatorie delle Vie Aeree e Patologie Fumo-correlate (CEMICEF), Dipartimento di Scienze Mediche, Sezione di Medicina Interna e Cardiorespiratoria, Università di Ferrara, Via Ludovico Ariosto 35, 44121 Ferrara, Italy
| | - Paul Kirkham
- Department of Biomedical Sciences, Faculty of Science and Engineering, University of Wolverhampton, Wolverhampton, UK
| | - Trevor T Hansel
- Centre for Respiratory Infection, National Heart and Lung Institute at Imperial College, St. Mary's Hospital, Mint Wing, Entrance C, Paddington, London, W2 1NY UK
| | - Kian Fan Chung
- Airway Disease Section, National Heart and Lung Institute, Imperial College London, London, UK
| | - Peter J Barnes
- Airway Disease Section, National Heart and Lung Institute, Imperial College London, London, UK
| | - Antonio Pastore
- Sezione di Scienze Otorinolaringoiatriche e Fisica Medica, Dipartimento di Scienze Biomediche e Chirurgico Specialistiche, University of Ferrara, Ferrara, Italy
| | - Stefano Pelucchi
- Sezione di Scienze Otorinolaringoiatriche e Fisica Medica, Dipartimento di Scienze Biomediche e Chirurgico Specialistiche, University of Ferrara, Ferrara, Italy
| | - Ian M Adcock
- Airway Disease Section, National Heart and Lung Institute, Imperial College London, London, UK
| | - Gaetano Caramori
- Centro Interdipartimentale per lo Studio delle Malattie Infiammatorie delle Vie Aeree e Patologie Fumo-correlate (CEMICEF), Dipartimento di Scienze Mediche, Sezione di Medicina Interna e Cardiorespiratoria, Università di Ferrara, Via Ludovico Ariosto 35, 44121 Ferrara, Italy
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13
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Garvin LM, Chen Y, Damsker JM, Rose MC. A novel dissociative steroid VBP15 reduces MUC5AC gene expression in airway epithelial cells but lacks the GRE mediated transcriptional properties of dexamethasone. Pulm Pharmacol Ther 2016; 38:17-26. [PMID: 27133900 DOI: 10.1016/j.pupt.2016.04.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/01/2015] [Revised: 03/09/2016] [Accepted: 04/28/2016] [Indexed: 10/21/2022]
Abstract
Overproduction of secretory mucins contributes to morbidity/mortality in inflammatory lung diseases. Inflammatory mediators directly increase expression of mucin genes, but few drugs have been shown to directly repress mucin gene expression. IL-1β upregulates the MUC5AC mucin gene in part via the transcription factors NFκB while the glucocorticoid Dexamethasone (Dex) transcriptionally represses MUC5AC expression by Dex-activated GR binding to two GRE cis-sites in the MUC5AC promoter in lung epithelial cells. VBP compounds (ReveraGen BioPharma) maintain anti-inflammatory activity through inhibition of NFκB but exhibit reduced GRE-mediated transcriptional properties associated with adverse side-effects and thus have potential to minimize harmful side effects of long-term steroid therapy in inflammatory lung diseases. We investigated VBP15 efficacy as an anti-mucin agent in two types of airway epithelial cells and analyzed the transcription factor activity and promoter binding associated with VBP15-induced MUC5AC repression. VBP15 reduced MUC5AC mRNA abundance in a dose- and time-dependent manner similar to Dex in the presence or absence of IL-1β in A549 and differentiated human bronchial epithelial cells. Repression was abrogated in the presence of RU486, demonstrating a requirement for GR in the VBP15-induced repression of MUC5AC. Inhibition of NFκB activity resulted in reduced baseline expression of MUC5AC indicating that constitutive activity maintains MUC5AC production. Chromatin immunoprecipitation analysis demonstrated lack of GR and of p65 (NFκB) binding to composite GRE domains in the MUC5AC promoter following VBP15 exposure of cells, in contrast to Dex. These data demonstrate that VBP15 is a novel anti-mucin agent that mediates the reduction of MUC5AC gene expression differently than the classical glucocorticoid, Dex.
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Affiliation(s)
- Lindsay M Garvin
- Department of Integrative Systems Biology, George Washington University School of Medicine and Health Sciences, Washington, DC, USA; Center for Genetic Medicine Research, Children's National Health System, Washington, DC, USA
| | - Yajun Chen
- Center for Genetic Medicine Research, Children's National Health System, Washington, DC, USA
| | | | - Mary C Rose
- Department of Integrative Systems Biology, George Washington University School of Medicine and Health Sciences, Washington, DC, USA; Center for Genetic Medicine Research, Children's National Health System, Washington, DC, USA.
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14
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Coursey TG, Tukler Henriksson J, Barbosa FL, de Paiva CS, Pflugfelder SC. Interferon-γ-Induced Unfolded Protein Response in Conjunctival Goblet Cells as a Cause of Mucin Deficiency in Sjögren Syndrome. THE AMERICAN JOURNAL OF PATHOLOGY 2016; 186:1547-58. [PMID: 27085137 DOI: 10.1016/j.ajpath.2016.02.004] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Revised: 01/19/2016] [Accepted: 02/01/2016] [Indexed: 12/21/2022]
Abstract
Goblet cells (GCs) are specialized secretory cells that produce mucins and a variety of other proteins. Significant conjunctival GC loss occurs in both experimental dry eye models and patients with keratoconjunctivitis sicca due to the induction of interferon (IFN)-γ. With the use of a primary murine culture model, we found that GCs are highly sensitive to IFN-γ with significantly reduced proliferation and altered structure with low concentrations. GC cultures treated with IFN-γ have increased gene expression of Muc2 and Muc5AC but do not express these mucin glycoproteins. We hypothesized that IFN-γ induces endoplasmic reticulum stress and the unfolded protein response (UPR) in GCs. Cultures treated with IFN-γ increased expression of UPR-associated genes and proteins. Increased GRP78 and sXBP1 expression was found in experimental dry eye and Sjögren syndrome models and was GC specific. Increased GRP78 was also found in the conjunctiva of patients with Sjögren syndrome at the gene and protein levels. Treatment with dexamethasone inhibited expression of UPR-associated genes and increased mucin production. These results indicate that induction of UPR by IFN-γ is an important cause of GC-associated mucin deficiency observed in aqueous-deficient dry eye. Therapies to block the effects of IFN-γ on the metabolically active endoplasmic reticulum in these cells might enhance synthesis and secretion of the protective GC mucins on the ocular surface.
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Affiliation(s)
- Terry G Coursey
- Ocular Surface Center, Department of Ophthalmology, Cullen Eye Institute, Baylor College of Medicine, Houston, Texas
| | - Johanna Tukler Henriksson
- Ocular Surface Center, Department of Ophthalmology, Cullen Eye Institute, Baylor College of Medicine, Houston, Texas
| | - Flavia L Barbosa
- Ocular Surface Center, Department of Ophthalmology, Cullen Eye Institute, Baylor College of Medicine, Houston, Texas
| | - Cintia S de Paiva
- Ocular Surface Center, Department of Ophthalmology, Cullen Eye Institute, Baylor College of Medicine, Houston, Texas
| | - Stephen C Pflugfelder
- Ocular Surface Center, Department of Ophthalmology, Cullen Eye Institute, Baylor College of Medicine, Houston, Texas.
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15
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Li Z, Wang J, Wang Y, Jiang H, Xu X, Zhang C, Li D, Xu C, Zhang K, Qi Y, Gong X, Tang C, Zhong N, Lu W. Bone morphogenetic protein 4 inhibits liposaccharide-induced inflammation in the airway. Eur J Immunol 2014; 44:3283-94. [PMID: 25142202 DOI: 10.1002/eji.201344287] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2013] [Revised: 08/03/2014] [Accepted: 08/15/2014] [Indexed: 01/02/2023]
Abstract
Bone morphogenetic protein 4 (BMP4) is a multifunctional growth factor that belongs to the TGF-β superfamily. The role of BMP4 in lung diseases is not fully understood. Here, we demonstrate that BMP4 was upregulated in lungs undergoing lipopolysaccharide (LPS)-induced inflammation, and in airway epithelial cells treated with LPS or TNF-α. BMP4 mutant (BMP4(+/-) ) mice presented with more severe lung inflammation in response to LPS or Pseudomonas aeruginosa, and lower bacterial load compared with that in BMP4(+/+) mice. Knockdown of BMP4 by siRNA increased LPS and TNF-α-induced IL-8 expression in 16HBE human airway epithelial cells and in primary human bronchial epithelial cells. Similarly, peritoneal macrophages from BMP4(+/-) mice produced greater levels of TNF-α and keratinocyte chemoattractant (KC) upon LPS treatment compared with cells from BMP4(+/+) mice. Administration of exogenous BMP4 attenuated the upregulation of TNF-α, IL-8, or KC induced by LPS and/or TNF-α in airway epithelial cells, and peritoneal macrophages. Finally, partial deficiency of BMP4 in BMP4(+/-) mice protected the animals from restrictive lung function reduction upon chronic LPS exposure. These results indicate that BMP4 plays an important anti-inflammatory role, controlling the strength and facilitating the resolution of acute lung inflammation; yet, BMP4 also contributes to lung function impairment during chronic lung inflammation.
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Affiliation(s)
- Zhengtu Li
- State Key Laboratory of Respiratory Diseases, Guangzhou Institute of Respiratory Disease, The First Affiliated Hospital, Guangzhou Medical University, Guangzhou, China
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16
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Chen Y, Garvin LM, Nickola TJ, Watson AM, Colberg-Poley AM, Rose MC. IL-1β induction of MUC5AC gene expression is mediated by CREB and NF-κB and repressed by dexamethasone. Am J Physiol Lung Cell Mol Physiol 2014; 306:L797-807. [PMID: 24487386 PMCID: PMC3989721 DOI: 10.1152/ajplung.00347.2013] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2013] [Accepted: 01/29/2014] [Indexed: 12/17/2022] Open
Abstract
Chronic airway diseases are characterized by inflammation and mucus overproduction. The MUC5AC mucin gene is upregulated by the proinflammatory cytokine interleukin-1 β (IL-1β) via activation of cAMP response element-binding protein (CREB) in the NCI-H292 cancer cell line and nuclear factor-κB (NF-κB) in the HBE1 transformed cell line, with each transcription factor binding to a cognate cis site in the proximal or distal region, respectively, of the MUC5AC promoter. We utilized primary differentiated human bronchial epithelial (HBE) and A549 lung adenocarcinoma cells to further investigate the contributions of CREB and NF-κB subunits to the IL-1β-induced upregulation of MUC5AC. Data show that ligand binding of IL-1β to the IL-1β receptor is required to increase MUC5AC mRNA abundance. Chromatin immunoprecipitation analyses show direct binding of CREB to the previously identified cAMP response element site and binding of p65 and p50 subunits to a novel NF-κB site in a mucin-regulatory domain in the proximal promoter and to a previously identified NF-κB site in the distal promoter. P50 binds to both NF-κB sites at 1 h following IL-1β exposure, but is replaced at 2 h by p65 in A549 cells and by a p50/p65 heterodimer in HBE cells. Thus IL-1β activates multiple domains in the MUC5AC promoter but exhibits some cell-specific responses, highlighting the complexity of MUC5AC transcriptional regulation. Data show that dexamethasone, a glucocorticoid that transcriptionally represses MUC5AC gene expression under constitutive conditions, also represses IL-1β-mediated upregulation of MUC5AC gene expression. A further understanding of mechanisms mediating MUC5AC regulation should lead to a honing of therapeutic approaches for the treatment of mucus overproduction in inflammatory lung diseases.
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Affiliation(s)
- Yajun Chen
- Children's National, 111 Michigan Ave NW, Washington, DC 20010.
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17
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Oliveira-Braga KA, Nepomuceno NA, Correia AT, Jatene FB, Pêgo-Fernandes PM. Effects of prednisone on mucociliary clearance in a murine model. Transplant Proc 2013; 44:2486-9. [PMID: 23026626 DOI: 10.1016/j.transproceed.2012.07.053] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
All transplant patients are at increased risk of developing pulmonary infections, a significant cause of morbidity and mortality. Immunosuppressants increase the incidence of lung infection by acting not only directly on the inflammatory cells, but also on the native immune system. Experimental studies have shown corticosteroid therapy, which is used in most immunosuppressive protocols after transplantation, to suppress mucus production by inhibiting calceiform. The objective of this study was to evaluate the effects of prednisone on mucociliary clearance. A total of 120 male Wistar rats were distributed into 4 groups. Animals in P1, P2, and P3 groups received daily doses of prednisone (0.625, 1.25, and 2.5 mg/kg/d), and hosts in the Sal group underwent gavage with saline solution (2.5 mL/d). After 7, 15, and 30 days, treatment, animals were killed. We assessed ciliary beating frequency (CBF), mucociliary transport velocity (MCTV), and mucus transportability (MT). There was no significant difference for CBF regarding dose (P = .089) or treatment duration (P = .175). MCTV values of 0.60 ± 0.14 in group P1, 0.59 ± 0.13 in group P2, 0.51 ± 0.19 in group P3, and 0.61 ± 0.08 Group Sal, showed P3 to significantly differ from P1 (P = .048) and Sal (P = .007) groups. Regardless of the prednisone dose, all groups displayed impaired MT compared with the Sal group: P1 (P = .02); P2 (P = .02) P3 (P = .03). There was no interaction between the therapy and the treatment time for CBF (P = .10), MCTV (P = .71), and MT (P = .64). Prednisone reduced the transportability of mucus even when administered at low doses; however, this change was not sufficient to alter the mucociliary clearance. Only high doses of prednisone impaired mucociliary clearance.
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Affiliation(s)
- K A Oliveira-Braga
- Laboratory of Thoracic Surgery Research, Heart Institute (InCor), Hospital das Clínicas, Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil.
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18
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Lillehoj EP, Kato K, Lu W, Kim KC. Cellular and molecular biology of airway mucins. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2013; 303:139-202. [PMID: 23445810 PMCID: PMC5593132 DOI: 10.1016/b978-0-12-407697-6.00004-0] [Citation(s) in RCA: 104] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Airway mucus constitutes a thin layer of airway surface liquid with component macromolecules that covers the luminal surface of the respiratory tract. The major function of mucus is to protect the lungs through mucociliary clearance of inhaled foreign particles and noxious chemicals. Mucus is comprised of water, ions, mucin glycoproteins, and a variety of other macromolecules, some of which possess anti-microbial, anti-protease, and anti-oxidant activities. Mucins comprise the major protein component of mucus and exist as secreted and cell-associated glycoproteins. Secreted, gel-forming mucins are mainly responsible for the viscoelastic property of mucus, which is crucial for effective mucociliary clearance. Cell-associated mucins shield the epithelial surface from pathogens through their extracellular domains and regulate intracellular signaling through their cytoplasmic regions. However, neither the exact structures of mucin glycoproteins, nor the manner through which their expression is regulated, are completely understood. This chapter reviews what is currently known about the cellular and molecular properties of airway mucins.
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Affiliation(s)
- Erik P. Lillehoj
- Department of Pediatrics, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Kosuke Kato
- Center for Inflammation, Translational and Clinical Lung Research and Department of Physiology, Temple University School of Medicine, Philadelphia, PA, USA
| | - Wenju Lu
- Guangzhou Institute of Respiratory Diseases, State Key Laboratory of Respiratory Diseases, The First Affiliated Hospital, Guangzhou Medical University, Guangzhou, PR China
| | - Kwang C. Kim
- Center for Inflammation, Translational and Clinical Lung Research and Department of Physiology, Temple University School of Medicine, Philadelphia, PA, USA
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19
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Chen Y, Watson AM, Williamson CD, Rahimi M, Liang C, Colberg-Poley AM, Rose MC. Glucocorticoid receptor and histone deacetylase-2 mediate dexamethasone-induced repression of MUC5AC gene expression. Am J Respir Cell Mol Biol 2012; 47:637-44. [PMID: 22798432 PMCID: PMC3547101 DOI: 10.1165/rcmb.2012-0009oc] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2012] [Accepted: 07/09/2012] [Indexed: 01/05/2023] Open
Abstract
Airway occlusion in obstructive airway diseases is caused in part by the overproduction of secretory mucin glycoproteins through the up-regulation of mucin (MUC) genes by inflammatory mediators. Some pharmacological agents, including the glucocorticoid dexamethasone (Dex), repress mucin concentrations in lung epithelial cancer cells. Here, we show that Dex reduces the expression of MUC5AC, a major airway mucin gene, in primary differentiated normal human bronchial epithelial (NHBE) cells in a dose-dependent and time-dependent manner, and that the Dex-induced repression is mediated by the glucocorticoid receptor (GR) and two glucocorticoid response elements (GREs) in the MUC5AC promoter. The pre-exposure of cells to RU486, a GR antagonist, and mutations in either the GRE3 or GRE5 cis-sites abolished the Dex-induced repression. Chromatin immunoprecipitation (ChIP) assays showed a rapid temporal recruitment of GR to the GRE3 and GRE5 cis-elements in the MUC5AC promoter in NHBE and in A549 cells. Immunofluorescence showed nuclear colocalization of GR and histone deacetylase-2 (HDAC2) in MUC5AC-expressing NHBE cells. ChIP also showed a rapid temporal recruitment of HDAC2 to the GRE3 and GRE5 cis-elements in the MUC5AC promoter in both cell types. The knockdown of HDAC2 by HDAC2-specific short interfering RNA prevented the Dex-induced repression of MUC5AC in NHBE and A549 cells. These data demonstrate that GR and HDAC2 are recruited to the GRE3 and GRE5 cis-sites in the MUC5AC promoter and mediate the Dex-induced cis repression of MUC5AC gene expression. A better understanding of the mechanisms whereby glucocorticoids repress MUC5AC gene expression may be useful in formulating therapeutic interventions in chronic lung diseases.
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Affiliation(s)
- Yajun Chen
- Center for Genetic Medicine Research, Children’s National Medical Center, Washington, DC; and
| | - Alan M. Watson
- Center for Genetic Medicine Research, Children’s National Medical Center, Washington, DC; and
| | | | - Michael Rahimi
- Center for Genetic Medicine Research, Children’s National Medical Center, Washington, DC; and
| | - Chong Liang
- Center for Genetic Medicine Research, Children’s National Medical Center, Washington, DC; and
| | - Anamaris M. Colberg-Poley
- Center for Genetic Medicine Research, Children’s National Medical Center, Washington, DC; and
- Department of Biochemistry and Molecular Biology
- Department of Integrative Systems Biology, and
- Department of Pediatrics, George Washington University, Washington, DC
| | - Mary C. Rose
- Center for Genetic Medicine Research, Children’s National Medical Center, Washington, DC; and
- Department of Biochemistry and Molecular Biology
- Department of Integrative Systems Biology, and
- Department of Pediatrics, George Washington University, Washington, DC
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20
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Takami S, Mizuno T, Oyanagi T, Tadaki H, Suzuki T, Muramatsu K, Takizawa T, Arakawa H. Glucocorticoids inhibit MUC5AC production induced by transforming growth factor-α in human respiratory cells. Allergol Int 2012; 61:451-9. [PMID: 22824974 DOI: 10.2332/allergolint.11-oa-0411] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2011] [Accepted: 03/19/2012] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND Mucus hypersecretion from airway epithelium is a characteristic feature of severe asthma. Glucocorticoids (GCs) may suppress mucus production and diminish the harmful airway obstruction. We investigated the ability of GCs to suppress mRNA expression and protein synthesis of a gene encoding mucin, MUC5AC, induced by transforming growth factor (TGF)-α in human mucoepidermoid carcinoma (NCI-H292) cells and the molecular mechanisms underlying the suppression. METHODS We determined if GCs such as dexamethasone (DEX), budesonide (BUD), and fluticasone (FP) could suppress MUC5AC production induced by a combination of TGF-α and double-strand RNA, polyinosinic-polycytidylic acid (polyI:C). MUC5AC mRNA expression and MUC5AC protein production were evaluated. The signaling pathways activated by TGF-α and their inhibition by GCs were tested using a phosphoprotein assay and MUC5AC promoter assay. RESULTS DEX significantly suppressed the expression of MUC5AC mRNA and MUC5AC protein induced by TGF-α. The activation of the MUC5AC promoter by TGF-α was significantly inhibited by DEX. DEX did not affect activation of downstream pathways of the EGF receptor or mRNA stability of MUC5AC transcripts. DEX, BUD, and FP suppressed MUC5AC protein expression induced by a combination of TGF-α and polyI:C in a dose-dependent manner. CONCLUSIONS GCs inhibited MUC5AC production induced by TGF-α alone or a combination of TGF-α and polyI:C; the repression may be mediated at the transcriptional but not post-transcriptional level.
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Affiliation(s)
- Satoru Takami
- Department of Pediatrics, Gunma University Graduate School of Medicine, 3−39−15 Showa-machi, Maebashi, Gunma, Japan
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Kyo Y, Kato K, Park YS, Gajghate S, Gajhate S, Umehara T, Lillehoj EP, Suzaki H, Kim KC. Antiinflammatory role of MUC1 mucin during infection with nontypeable Haemophilus influenzae. Am J Respir Cell Mol Biol 2012; 46:149-56. [PMID: 22298528 DOI: 10.1165/rcmb.2011-0142oc] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
MUC1 (or Muc1 in nonhuman species) is a membrane-tethered mucin expressed on the apical surface of mucosal epithelia (including those of the airways) that suppresses Toll-like receptor (TLR) signaling. We sought to determine whether the anti-inflammatory effect of MUC1 is operative during infection with nontypeable Haemophilus influenzae (NTHi), and if so, which TLR pathway was affected. Our results showed that: (1) a lysate of NTHi increased the early release of IL-8 and later production of MUC1 protein by A549 cells in dose-dependent and time-dependent manners, compared with vehicle control; (2) both effects were attenuated after transfection of the cells with a TLR2-targeting small interfering (si) RNA, compared with a control siRNA; (3) the NTHi-induced release of IL-8 was suppressed by an overexpression of MUC1, and was enhanced by the knockdown of MUC1; (4) the TNF-α released after treatment with NTHi was sufficient to up-regulate MUC1, which was completely inhibited by pretreatment with a soluble TNF-α receptor; and (5) primary murine tracheal surface epithelial (MTSE) cells from Muc1 knockout mice exhibited an increased in vitro production of NTHi-stimulated keratinocyte chemoattractant compared with MTSE cells from Muc1-expressing animals. These results suggest a hypothetical feedback loop model whereby NTHi activates TLRs (mainly TLR2) in airway epithelial cells, leading to the increased production of TNF-α and IL-8, which subsequently up-regulate the expression of MUC1, resulting in suppressed TLR signaling and decreased production of IL-8. This report is the first, to the best of our knowledge, demonstrating that the inflammatory response in airway epithelial cells during infection with NTHi is controlled by MUC1 mucin, mainly through the suppression of TLR2 signaling.
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Affiliation(s)
- Yoshiyuki Kyo
- Department of Physiology, Temple University School of Medicine, Philadelphia, PA 19140, USA
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Park YS, Lillehoj EP, Kato K, Park CS, Kim KC. PPARγ inhibits airway epithelial cell inflammatory response through a MUC1-dependent mechanism. Am J Physiol Lung Cell Mol Physiol 2012; 302:L679-87. [PMID: 22268120 DOI: 10.1152/ajplung.00360.2011] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
This study was conducted to examine the relationship between the peroxisome proliferator-associated receptor-γ (PPARγ) and MUC1 mucin, two anti-inflammatory molecules expressed in the airways. Treatment of A549 lung epithelial cells or primary mouse tracheal surface epithelial (MTSE) cells with phorbol 12-myristate 13-acetate (PMA) increased the levels of tumor necrosis factor (TNF)-α in cell culture media compared with cells treated with vehicle alone. Overexpression of MUC1 in A549 cells decreased PMA-stimulated TNF-α levels, whereas deficiency of Muc1 expression in MTSE cells from Muc1 null mice increased PMA-induced TNF-α levels. Treatment of A549 or MTSE cells with the PPARγ agonist troglitazone (TGN) blocked the ability of PMA to stimulate TNF-α levels. However, the effect of TGN required the presence of MUC1/Muc1, since no differences in TNF-α levels were seen between PMA and PMA plus TGN in MUC1/Muc1-deficient cells. Similarly, whereas TGN decreased interleukin-8 (IL-8) levels in culture media of MUC1-expressing A549 cells treated with Pseudomonas aeruginosa strain K (PAK), no differences in IL-8 levels were seen between PAK and PAK plus TGN in MUC1-nonexpressing cells. EMSA confirmed the presence of a PPARγ-binding element in the MUC1 gene promoter. Finally, TGN treatment of A549 cells increased MUC1 promoter activity measured using a MUC1-luciferase reporter gene, augmented MUC1 mRNA levels by quantitative RT-PCR, and enhanced MUC1 protein expression by Western blot analysis. These combined data are consistent with the hypothesis that PPARγ stimulates MUC1/Muc1 expression, thereby blocking PMA/PAK-induced TNF-α/IL-8 production by airway epithelial cells.
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Affiliation(s)
- Yong Sung Park
- Center for Inflammation, Translational and Clinical Lung Research, Temple Univ. School of Medicine, Philadelphia, PA 19140, USA
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Seagrave J, Albrecht H, Park YS, Rubin B, Solomon G, Kim KC. Effect of guaifenesin on mucin production, rheology, and mucociliary transport in differentiated human airway epithelial cells. Exp Lung Res 2011; 37:606-14. [DOI: 10.3109/01902148.2011.623116] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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Kanoh S, Tanabe T, Rubin BK. IL-13-induced MUC5AC production and goblet cell differentiation is steroid resistant in human airway cells. Clin Exp Allergy 2011; 41:1747-56. [PMID: 22092504 DOI: 10.1111/j.1365-2222.2011.03852.x] [Citation(s) in RCA: 86] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2011] [Revised: 07/20/2011] [Accepted: 07/25/2011] [Indexed: 11/28/2022]
Abstract
BACKGROUND Glucocorticosteroids (GCS) are used to treat bronchial asthma, but are not uniformly effective, especially in severe asthma. IL-13 is a T helper type 2 cytokine implicated in the pathogenesis of asthma, and IL-13 induces mucus production and goblet cell hyperplasia in airway epithelial cells. The effect of GCS on IL-13-induced mucin production is not well characterized. OBJECTIVE The aim of this study was to evaluate the effect of dexamethasone (Dex), a potent synthetic GCS, on IL-13-induced MUC5AC mucin expression and goblet cell proliferation in differentiated normal human bronchial epithelial cells (NHBECs). METHODS NHBECs were cultured for 14 days at an air-liquid interface with IL-13, with or without Dex. MUC5AC protein secretion and mRNA expression was determined using ELISA and quantitative real-time PCR. IL-8 production was assayed using ELISA. Histochemical analysis was performed using H&E and periodic acid-Schiff stain, and MUC5AC immunostaining. RESULTS Although Dex dose dependently inhibited IL-8 release induced by 5 ng/mL IL-13, Dex 0.001-1 μg/mL had no effect on IL-13 induced MUC5AC protein secretion or mRNA expression. Dex paradoxically increased MUC5AC induced by IL-13 at 0.5 and 1 ng/mL, but had no effect alone or with IL-13 at 0.1 ng/mL. Dex 0.001-1 μg/mL did not inhibit the differentiation of cells into goblet cells and MUC5AC-positive cells induced by IL-13. CONCLUSION AND CLINICAL RELEVANCE Dex at therapeutic concentrations did not inhibit the effects of IL-13 on goblet cell differentiation, characteristic of severe asthma. Paradoxically, MUC5AC production was increased with lower dose IL-13 exposure. This may lead to airway mucus obstruction commonly seen in life-threatening asthma.
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Affiliation(s)
- S Kanoh
- Department of Pediatrics, Virginia Commonwealth University School of Medicine, Richmond, VA 23298, USA
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Sprenger L, Goldmann T, Vollmer E, Steffen A, Wollenberg B, Zabel P, Hauber HP. Dexamethasone and N-acetyl-cysteine attenuate Pseudomonas aeruginosa-induced mucus expression in human airways. Pulm Pharmacol Ther 2011; 24:232-9. [DOI: 10.1016/j.pupt.2010.11.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/28/2010] [Revised: 11/11/2010] [Accepted: 11/28/2010] [Indexed: 11/29/2022]
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Ali M, Lillehoj EP, Park Y, Kyo Y, Kim KC. Analysis of the proteome of human airway epithelial secretions. Proteome Sci 2011; 9:4. [PMID: 21251289 PMCID: PMC3036598 DOI: 10.1186/1477-5956-9-4] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2010] [Accepted: 01/20/2011] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND Airway surface liquid, often referred to as mucus, is a thin layer of fluid covering the luminal surface that plays an important defensive role against foreign particles and chemicals entering the lungs. Airway mucus contains various macromolecules, the most abundant being mucin glycoproteins, which contribute to its defensive function. Airway epithelial cells cultured in vitro secrete mucins and nonmucin proteins from their apical surface that mimics mucus production in vivo. The current study was undertaken to identify the polypeptide constituents of human airway epithelial cell secretions to gain a better understanding of the protein composition of respiratory mucus. RESULTS Fifty-five proteins were identified in the high molecular weight fraction of apical secretions collected from in vitro cultures of well-differentiated primary human airway epithelial cells and isolated under physiological conditions. Among these were MUC1, MUC4, MUC5B, and MUC16 mucins. By proteomic analysis, the nonmucin proteins could be classified as inflammatory, anti-inflammatory, anti-oxidative, and/or anti-microbial. CONCLUSIONS Because the majority of the nonmucin proteins possess molecular weights less than that selected for analysis, it is theoretically possible that they may associate with the high molecular weight and negatively charged mucins to form a highly ordered structural organization that is likely to be important for maintaining the proper defensive function of airway mucus.
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Affiliation(s)
- Mehboob Ali
- Department of Physiology and Lung Center, Temple University School of Medicine, Philadelphia, PA, USA.,Department of Pharmacology and Experimental Therapeutics, Thomas Jefferson University, 1020 Locust Street, JAH 364, Philadelphia, PA 19107, USA
| | - Erik P Lillehoj
- Department of Pediatrics, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Yongsung Park
- Department of Physiology and Lung Center, Temple University School of Medicine, Philadelphia, PA, USA
| | - Yoshiyuki Kyo
- Department of Physiology and Lung Center, Temple University School of Medicine, Philadelphia, PA, USA
| | - K Chul Kim
- Department of Physiology and Lung Center, Temple University School of Medicine, Philadelphia, PA, USA
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Li Y, Dinwiddie DL, Harrod KS, Jiang Y, Kim KC. Anti-inflammatory effect of MUC1 during respiratory syncytial virus infection of lung epithelial cells in vitro. Am J Physiol Lung Cell Mol Physiol 2010; 298:L558-63. [PMID: 20081068 DOI: 10.1152/ajplung.00225.2009] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
MUC1 is a transmembrane glycoprotein expressed on the apical surface of airway epithelial cells and plays an anti-inflammatory role during airway bacterial infection. In this study, we determined whether the anti-inflammatory effect of MUC1 is also operative during the respiratory syncytial virus (RSV) infection. The lung epithelial cell line A549 was treated with RSV, and the production of TNFalpha and the levels of MUC1 protein were monitored temporally during the course of infection by ELISA and Western blot analysis. Small inhibitory RNA (siRNA) transfection was utilized to assess the role of MUC1 in regulating RSV-mediated inflammatory responses by lung epithelial cells. Our results revealed that: 1) following RSV infection, an increase in MUC1 level was preceded by an increase in TNFalpha production and completely inhibited by soluble TNF receptor (TNFR); and 2) knockdown of MUC1 using MUC1 siRNA resulted in a greater increase in TNFalpha level following RSV infection compared with control siRNA treatment. We conclude that the RSV-induced increase in the TNFalpha levels upregulates MUC1 through its interaction with TNFR, which in turn suppresses further increase in TNFalpha by RSV, thus forming a negative feedback loop in the control of RSV-induced inflammation. This is the first demonstration showing that MUC1 can suppress the virus-induced inflammatory responses.
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Affiliation(s)
- Yusheng Li
- Department of Physiology and Lung Center, Temple University School of Medicine, Philadelphia, Pennsylvania 19140, USA
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Chen L, Wang T, Zhang JY, Zhang SF, Liu DS, Xu D, Wang X, Chen YJ, Wen FQ. Toll-like Receptor 4 Relates to Lipopolysaccharide-induced Mucus Hypersecretion in Rat Airway. Arch Med Res 2009; 40:10-7. [DOI: 10.1016/j.arcmed.2008.10.005] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2008] [Accepted: 09/22/2008] [Indexed: 11/27/2022]
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Komatsu K, Jono H, Lim JH, Imasato A, Xu H, Kai H, Yan C, Li JD. Glucocorticoids inhibit nontypeable Haemophilus influenzae-induced MUC5AC mucin expression via MAPK phosphatase-1-dependent inhibition of p38 MAPK. Biochem Biophys Res Commun 2008; 377:763-8. [DOI: 10.1016/j.bbrc.2008.10.091] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2008] [Accepted: 10/08/2008] [Indexed: 12/31/2022]
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Martínez-Antón A, de Bolós C, Alobid I, Benítez P, Roca-Ferrer J, Picado C, Mullol J. Corticosteroid therapy increases membrane-tethered while decreases secreted mucin expression in nasal polyps. Allergy 2008; 63:1368-76. [PMID: 18547287 DOI: 10.1111/j.1398-9995.2008.01678.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
BACKGROUND Mucus hypersecretion is a hallmark of nasal polyposis (NP). Corticosteroids (CS) are first-line treatment for NP, decreasing their size and inflammatory component. However, their effect on mucin production is not well-understood. The aim of this (pilot) study was to investigate CS effect on mucin expression in NP. METHODS Patients were randomized in control (n = 9) and treatment (oral prednisone for 2 weeks and intranasal budesonide for 12 weeks; n = 23) groups. Nasal polyposis from nonasthmatic (NP; n = 13), aspirin-tolerant (NP-ATA; n = 11) and aspirin-intolerant (NP-AIA; n = 8) asthmatics were studied. Nasal polyposis biopsies were obtained before (w0) and after 2 (w2) and 12 (w12) weeks of CS treatment. Secreted (MUC5AC, MUC5B and MUC8) and membrane-tethered (MUC1, MUC4) mucins (immunohistochemistry) and goblet cells (Alcian blue-periodic acid Schiff) were quantified in both epithelium and glands. Rhinorrea and nasal obstruction were also assessed. RESULTS At w2, steroids increased MUC1 (from 70 to 97.5) and MUC4 (from 80 to 100) in NP-ATA patients' epithelium compared with baseline (w0). At w12, steroids decreased MUC5AC (from 40 to 5) and MUC5B (from 45 to 2.5) in NP-ATA patients' epithelium and glands, respectively, compared with baseline. No mucin presented significant changes in NP-AIA patients. MUC5AC and MUC5B expression correlated with goblet and mucous cell numbers, respectively, and MUC5AC also with rhinorrea score. CONCLUSIONS These results suggest: (i) CS up-regulate membrane (MUC1, MUC4) while down-regulate secreted (MUC5AC, MUC5B) mucins; (ii) there exists a link between secreted mucin expression and goblet cell hyperplasia; and (iii) NP from AIA may develop resistance to CS treatment.
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Affiliation(s)
- A Martínez-Antón
- Immunoal.lèrgia Respiratòria Clínica i Experimental, Institut d'Investigacions Biomèdiques August Pi i Sunyer, Barcelona, Spain
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Effect of steroids, acetyl-cysteine and calcium-activated chloride channel inhibitors on allergic mucin expression in sinus mucosa. Laryngoscope 2008; 118:1528-33. [PMID: 18596559 DOI: 10.1097/mlg.0b013e31817b0732] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
OBJECTIVES/HYPOTHESIS Allergic inflammation of the upper airways is commonly associated with mucus hypersecretion. At present, there is no specific mucus regulating drug available. Our goal was to investigate the effect of glucocorticosteroids, acetyl-cysteine (ACC), and calcium-activated chloride channel (CLCA) inhibitors in a model of Th2 type cytokine induced mucin expression in human airway mucosa. STUDY DESIGN Prospective. METHODS Explanted tissue from human sinus mucosa was stimulated with interleukin (IL)-4, IL-9, or IL-13. Different concentrations of dexamethasone, ACC, or CLCA inhibitors [niflumic acid (NFA) or MSI-2216] were added to stimulated tissue. Epithelial mucin expression was quantified using periodic acid-Schiff staining. RESULTS IL-4, IL-9, and IL-13 significantly increased epithelial mucin expression (P < .05). Dexamethasone reduced Th2 type cytokine induced mucin expression in a dose-dependent manner being statistically significant at concentrations >or=4.0 micromol/L (IL-4) and >or=40.0 micromol/L (IL-9 and IL-13) (P < .05). ACC had no significant effect on IL-4 and IL-13 induced mucin expression, whereas IL-9 induced mucin expression was significantly decreased at concentrations >or=3.0 mmol/L (P < .05). NFA and MSI-2216 decreased Th2 type cytokine induced mucin expression in a dose-dependent manner. This effect was statistically significant at concentrations >or=100 micromol/L (NFA) and >or=50 micromol/L (MSI-2216) (P < .05). CONCLUSIONS Th2 type cytokines can induce mucin expression in a model of explanted human airway mucosa. Th2 type cytokine induced mucin expression can be effectively reduced by either glucocorticosteroids or CLCA inhibitors ex vivo. Besides glucocorticosteroids CLCA inhibitors may offer an alternative therapeutic approach to treat allergic mucus hypersecretion.
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Mishra NC, Rir-Sima-Ah J, Langley RJ, Singh SP, Peña-Philippides JC, Koga T, Razani-Boroujerdi S, Hutt J, Campen M, Kim KC, Tesfaigzi Y, Sopori ML. Nicotine primarily suppresses lung Th2 but not goblet cell and muscle cell responses to allergens. THE JOURNAL OF IMMUNOLOGY 2008; 180:7655-63. [PMID: 18490768 DOI: 10.4049/jimmunol.180.11.7655] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Allergic asthma, an inflammatory disease characterized by the infiltration and activation of various leukocytes, the production of Th2 cytokines and leukotrienes, and atopy, also affects the function of other cell types, causing goblet cell hyperplasia/hypertrophy, increased mucus production/secretion, and airway hyperreactivity. Eosinophilic inflammation is a characteristic feature of human asthma, and recent evidence suggests that eosinophils also play a critical role in T cell trafficking in animal models of asthma. Nicotine is an anti-inflammatory, but the association between smoking and asthma is highly contentious and some report that smoking cessation increases the risk of asthma in ex-smokers. To ascertain the effects of nicotine on allergy/asthma, Brown Norway rats were treated with nicotine and sensitized and challenged with allergens. The results unequivocally show that, even after multiple allergen sensitizations, nicotine dramatically suppresses inflammatory/allergic parameters in the lung including the following: eosinophilic/lymphocytic emigration; mRNA and/or protein expression of the Th2 cytokines/chemokines IL-4, IL-5, IL-13, IL-25, and eotaxin; leukotriene C(4); and total as well as allergen-specific IgE. Although nicotine did not significantly affect hexosaminidase release, IgG, or methacholine-induced airway resistance, it significantly decreased mucus content in bronchoalveolar lavage; interestingly, however, despite the strong suppression of IL-4/IL-13, nicotine significantly increased the intraepithelial-stored mucosubstances and Muc5ac mRNA expression. These results suggest that nicotine modulates allergy/asthma primarily by suppressing eosinophil trafficking and suppressing Th2 cytokine/chemokine responses without reducing goblet cell metaplasia or mucous production and may explain the lower risk of allergic diseases in smokers. To our knowledge this is the first direct evidence that nicotine modulates allergic responses.
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Affiliation(s)
- Neerad C Mishra
- Immunology Program, Lovelace Respiratory Research Institute, Albuquerque, NM 87108, USA
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Stellato C. Glucocorticoid actions on airway epithelial responses in immunity: functional outcomes and molecular targets. J Allergy Clin Immunol 2008; 120:1247-63; quiz 1264-5. [PMID: 18073120 DOI: 10.1016/j.jaci.2007.10.041] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2007] [Revised: 10/26/2007] [Accepted: 10/29/2007] [Indexed: 12/27/2022]
Abstract
Research on the biology of airway epithelium in the last decades has progressively uncovered the many roles of this cell type during the immune response. Far from the early view of the epithelial layer simply as a passive barrier, the airway epithelium is now considered a central player in mucosal immunity, providing innate mechanisms of first-line host defense as well as facilitating adaptive immune responses. Alterations of the epithelial phenotype are primarily involved in the pathogenesis of allergic airways disease, particularly in severe asthma. Appreciation of the epithelium as target of glucocorticoid therapy has also grown, because of studies defining the pathways and mediators affected by glucocorticoids, and studies illustrating the relevance of the control of the response from epithelium in the overall efficacy of topical and systemic therapy with glucocorticoids. Studies of the mechanism of action of glucocorticoids within the biology of the immune response of the epithelium have uncovered mechanisms of gene regulation involving both transcriptional and posttranscriptional events. The view of epithelium as therapeutic target therefore has plenty of room to evolve, as new knowledge on the role of epithelium in immunity is established and novel pathways mediating glucocorticoid regulation are elucidated.
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Affiliation(s)
- Cristiana Stellato
- Division of Allergy and Clinical Immunology, Johns Hopkins University, Baltimore, MD, USA.
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Ueno K, Koga T, Kato K, Golenbock DT, Gendler SJ, Kai H, Kim KC. MUC1 mucin is a negative regulator of toll-like receptor signaling. Am J Respir Cell Mol Biol 2007; 38:263-8. [PMID: 18079492 DOI: 10.1165/rcmb.2007-0336rc] [Citation(s) in RCA: 130] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
MUC1 (MUC1 in humans and Muc1 in nonhuman species) is a transmembrane mucin-like glycoprotein expressed in epithelial cells lining various mucosal surfaces as well as hematopoietic cells. Recently, we showed that Muc1(-/-) mice exhibited greater inflammatory responses to Pseudomonas aeruginosa or its flagellin compared with their wild-type littermates, and our studies with cultured cells revealed that MUC1/Muc1 suppressed the Toll-like receptor (TLR) 5 signaling pathway, suggesting its anti-inflammatory role. Here we demonstrate that other TLR signaling (TLR2, 3, 4, 7, and 9) is also suppressed by MUC1/Muc1. The results from this study suggest that MUC1/Muc1 may play a crucial role during airway infection and inflammation by various pathogenic bacteria and viruses.
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Affiliation(s)
- Keiko Ueno
- Lovelace Respiratory Research Institute, 2425 Ridgecrest Dr., S.E., Albuquerque, NM 87108-5127, USA
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Hauber HP, Goldmann T, Vollmer E, Wollenberg B, Zabel P. Effect of Dexamethasone and ACC on Bacteria-Induced Mucin Expression in Human Airway Mucosa. Am J Respir Cell Mol Biol 2007; 37:606-16. [PMID: 17600317 DOI: 10.1165/rcmb.2006-0404oc] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Gram-negative bacteria can stimulate mucin production, but excessive mucus supports bacterial infection and consequently leads to airway obstruction. Therefore, the effect of dexamethasone (DEX) and the antioxidant acetyl-cysteine (ACC) on bacteria-induced mucus expression was investigated. Explanted human airway mucosa and mucoepidermoid cells (Calu-3) were stimulated with lipopolysaccharide (LPS) or PAM3 (a synthetic lipoprotein). DEX or ACC were added to either LPS- or PAM3-stimulated airway mucosa or Calu-3 cells. Mucin mRNA expression (MUC5AC) and total mucus glycoconjugates (mucin protein) were quantified using real-time PCR and periodic acid Schiff staining. LPS and PAM3 significantly increased mucin expression in airway mucosa and Calu-3 cells (P < 0.05). DEX alone had no significant effect on mucin expression in airway mucosa or Calu-3 cells (P > 0.05). In contrast, DEX significantly reduced LPS- and PAM3-induced mucin expression in explanted mucosal tissue and mucin expression in Calu-3 cells (P < 0.05). In explanted human airway mucosa ACC alone significantly increased mucin expression (P < 0.05). In contrast, ACC significantly decreased LPS- and PAM3-induced mucin expression (P < 0.05). In Calu-3 cells ACC alone had no significant effect on mucin expression (P > 0.05). ACC decreased LPS- and PAM3-induced mucin expression, but this effect was not significant (P > 0.05). These data suggest that DEX can effectively reduce bacteria-induced mucin expression in the airways. ACC alone may increase mucin expression in noninfected mucosa, but it decreased bacteria-induced mucin expression. Further studies are warranted to evaluate whether the effect of DEX or ACC is clinically relevant.
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Affiliation(s)
- Hans-Peter Hauber
- Medical Clinic, Research Center Borstel, Research Center Borstel, Borstel, Germany.
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Koga T, Kuwahara I, Lillehoj EP, Lu W, Miyata T, Isohama Y, Kim KC. TNF-alpha induces MUC1 gene transcription in lung epithelial cells: its signaling pathway and biological implication. Am J Physiol Lung Cell Mol Physiol 2007; 293:L693-701. [PMID: 17575006 DOI: 10.1152/ajplung.00491.2006] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The current study was conducted to elucidate the mechanism through which TNF-alpha stimulates expression of MUC1, a membrane-tethered mucin. A549 human lung alveolar cells treated with TNF-alpha exhibited significantly higher MUC1 protein levels in detergent lysates compared with cells treated with vehicle alone. Increased MUC1 protein levels were correlated with significantly higher levels of MUC1 mRNA in TNF-alpha-treated cells compared with controls. However, TNF-alpha did not alter MUC1 transcript stability, implying increased de novo transcription induced by the cytokine. TNF-alpha increased MUC1 gene promoter activity in A549 cells transfected with a promoter-luciferase reporter plasmid. Both U0126, an inhibitor of MEK1/2, and dominant negative ERK1 prevented TNF-alpha-induced MUC1 promoter activation, and anti-TNFR1 antibody blocked TNF-alpha-stimulated ERK1/2 activation. MUC1 promoter activation by TNF-alpha also was blocked by mithramycin A, an inhibitor of Sp1, as well as either deletion or mutation of a putative Sp1 binding site in the MUC1 promoter located between nucleotides -99 and -90. TNF-alpha-stimulated binding of Sp1 to the MUC1 promoter in intact cells was demonstrated by chromatin immunoprecipitation assay. We conclude that TNF-alpha induces MUC1 gene transcription through a TNFR1 --> MEK1/2 --> ERK1 --> Sp1 pathway.
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MESH Headings
- Animals
- Antigens, Neoplasm/genetics
- Antigens, Neoplasm/metabolism
- Binding Sites
- Cell Line, Tumor
- Cell Survival/drug effects
- Dose-Response Relationship, Drug
- Epithelial Cells/drug effects
- Epithelial Cells/metabolism
- Gene Expression Regulation, Neoplastic/drug effects
- Humans
- Lung/cytology
- Lung/drug effects
- Lung/metabolism
- Mice
- Mitogen-Activated Protein Kinase 3/metabolism
- Mucin-1
- Mucins/genetics
- Mucins/metabolism
- Promoter Regions, Genetic/genetics
- Protein Binding/drug effects
- RNA Stability/drug effects
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Receptors, Tumor Necrosis Factor, Type I/metabolism
- Signal Transduction/drug effects
- Sp1 Transcription Factor/metabolism
- Time Factors
- Transcription, Genetic/drug effects
- Tumor Necrosis Factor-alpha/pharmacology
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Affiliation(s)
- Takeshi Koga
- Lovelace Respiratory Research Institute, Albuquerque, New Mexico 87108, USA
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38
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Theodoropoulos G, Carraway KL. Molecular signaling in the regulation of mucins. J Cell Biochem 2007; 102:1103-16. [DOI: 10.1002/jcb.21539] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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39
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Abstract
PURPOSE OF REVIEW Asthma is characterized by chronic airway inflammation and a mucus hypersecretory phenotype comprising excess mucus secretion, goblet cell hyperplasia and submucosal gland hypertrophy. This augmented mucus secretion has been relatively undervalued in asthma compared with airway inflammation. However, mucus plugging contributes to airflow limitation and airway hyperresponsiveness, and to morbidity and mortality in asthma. We review recent contributions to this field and therapeutic avenues to control mucus hypersecretion. RECENT FINDINGS A distinct mucus hypersecretory phenotype may present in asthma. Overexpression of MUC5AC, MUC5B and MUC2 have been described in asthma secretions, but identification of defined biochemical abnormalities and polymorphisms of mucin genes linked to asthma remains elusive. Activation of epidermal growth factor receptor (EGFR) activation appears central in transducing many different stimuli, including oxidative stress, proteases and cytokines. In contrast, nitrosative stress has barely been investigated. The existence of crosstalk between EGFR and other receptor systems may provide new clues regarding the activity of acetylcholine, adenosine and other agonists of G-protein-coupled receptors and other receptor families on mucin secretion. Modern techniques for noninvasive detection of mucus pathology will advance clinical research in this field. SUMMARY Airway mucus hypersecretion as a part of airway remodelling represents a problem in asthma, and studies of pathophysiology and therapeutic approaches are therefore warranted. Identification of targets such as the EGFR cascade, which are crucial in excessive and abnormal mucus secretion, may lead to the rational design of new antihypersecretory drugs that may enhance future asthma treatment.
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Affiliation(s)
- Esteban J Morcillo
- Department of Pharmacology, Faculty of Medicine, University of Valencia, and Research Foundation of University General Hospital Consortium, Valencia, Spain.
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40
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Abstract
This review focuses on the role and regulation of mucin glycoproteins (mucins) in airway health and disease. Mucins are highly glycosylated macromolecules (> or =50% carbohydrate, wt/wt). MUC protein backbones are characterized by numerous tandem repeats that contain proline and are high in serine and/or threonine residues, the sites of O-glycosylation. Secretory and membrane-tethered mucins contribute to mucociliary defense, an innate immune defense system that protects the airways against pathogens and environmental toxins. Inflammatory/immune response mediators and the overproduction of mucus characterize chronic airway diseases: asthma, chronic obstructive pulmonary diseases (COPD), or cystic fibrosis (CF). Specific inflammatory/immune response mediators can activate mucin gene regulation and airway remodeling, including goblet cell hyperplasia (GCH). These processes sustain airway mucin overproduction and contribute to airway obstruction by mucus and therefore to the high morbidity and mortality associated with these diseases. Importantly, mucin overproduction and GCH, although linked, are not synonymous and may follow from different signaling and gene regulatory pathways. In section i, structure, expression, and localization of the 18 human MUC genes and MUC gene products having tandem repeat domains and the specificity and application of MUC-specific antibodies that identify mucin gene products in airway tissues, cells, and secretions are overviewed. Mucin overproduction in chronic airway diseases and secretory cell metaplasia in animal model systems are reviewed in section ii and addressed in disease-specific subsections on asthma, COPD, and CF. Information on regulation of mucin genes by inflammatory/immune response mediators is summarized in section iii. In section iv, deficiencies in understanding the functional roles of mucins at the molecular level are identified as areas for further investigations that will impact on airway health and disease. The underlying premise is that understanding the pathways and processes that lead to mucus overproduction in specific airway diseases will allow circumvention or amelioration of these processes.
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Affiliation(s)
- Mary Callaghan Rose
- Research Center for Genetic Medicine, Room 5700, Children's National Medical Center, 111 Michigan Avenue NW, Washington, DC 20010, USA.
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41
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Voynow JA, Gendler SJ, Rose MC. Regulation of mucin genes in chronic inflammatory airway diseases. Am J Respir Cell Mol Biol 2006; 34:661-5. [PMID: 16456183 DOI: 10.1165/rcmb.2006-0035sf] [Citation(s) in RCA: 155] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
In this review, we summarize work over the past 15 years on mucin gene expression and regulation in the lung, as well as how mucin gene expression is altered in chronic lung diseases. This field owes a great debt to Carol Basbaum for her pioneering work in dissecting signaling pathways regulating mucin gene expression and for her tremendous energy in promoting the importance of understanding the basic pathogenic mechanisms that drive mucus overproduction in cystic fibrosis, chronic obstructive pulmonary disease, and asthma.
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Affiliation(s)
- Judith A Voynow
- Department of Pediatrics, Duke University Medical Center, Durham, NC 27710, USA.
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42
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Chen Y, Nickola TJ, DiFronzo NL, Colberg-Poley AM, Rose MC. Dexamethasone-mediated repression of MUC5AC gene expression in human lung epithelial cells. Am J Respir Cell Mol Biol 2005; 34:338-47. [PMID: 16239644 PMCID: PMC2644199 DOI: 10.1165/rcmb.2005-0176oc] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Glucocorticoids regulate gene expression via binding of the ligand-activated glucocorticoid receptor (GR) to glucocorticoid-responsive elements (GRE) in target gene promoters. The MUC5AC gene, which encodes the protein backbone of an abundant secreted airway mucin, has several putative GRE cis-elements in its 5' sequence. Mechanism(s) whereby glucocorticoids regulate mucin genes have not previously been described. In this study, the glucocorticoid dexamethasone (Dex) decreased MUC5AC mRNA abundance in A549 and NCI-H292 cell lines and primary differentiated normal bronchial epithelial cells by 50-80%, suggesting a common mechanism of MUC5AC gene repression in human lung epithelial cells. Kinetic analyses showed that MUC5AC mRNA was not significantly decreased until 6 h after Dex exposure, and that nuclear translocation of GR was biphasic, suggesting that Dex-mediated cis-repression of MUC5AC gene expression was a delayed response of GR translocation. Transfection analyses demonstrated that Dex transcriptionally repressed the MUC5AC promoter. Electrophoretic mobility shift assays with wild-type and mutant oligonucleotide probes showed that GR bound to two GRE cis-sites (nucleotides -930 to -912 and -369 to -351) in the MUC5AC promoter. Analyses of mutated MUC5AC promoter constructs demonstrated that NF-kappaB cis-sites were not involved in Dex-mediated repression of MUC5AC. Dex did not alter mRNA stability of MUC5AC transcripts. Taken together, the data indicate that Dex transcriptionally mediates repression of MUC5AC gene expression in human lung epithelial cells at quiescent states after binding of GR to one or more GRE cis-elements in the MUC5AC promoter.
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Affiliation(s)
- Yajun Chen
- Center for Genetic Medicine Research, Children's Research Institute, Washington, DC 20010, USA
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