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Yu H, Luo C, Linghu R, Yang J, Wu H. Ezrin Contributes to the Damage of Airway Epithelial Barrier Related to Diabetes Mellitus. J Inflamm Res 2024; 17:2609-2621. [PMID: 38689797 PMCID: PMC11060175 DOI: 10.2147/jir.s449487] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2023] [Accepted: 04/18/2024] [Indexed: 05/02/2024] Open
Abstract
Background Diabetes mellitus predisposes individuals to respiratory infections. The airway epithelial barrier provides defense against inhaled antigens and pathogens. Ezrin, is a component of the membrane-cytoskeleton that maintains the cellular morphology, intercellular adhesion, and barrier function of epithelial cells. This study aimed to explore the role of ezrin in airway epithelial barrier damage and correlate its expression and activation with diabetes mellitus. Methods This study was performed in a murine model of diabetes mellitus and with human bronchial epithelial BEAS-2B cells using real-time PCR, Western blotting, immunohistochemical and immunofluorescence staining. Ezrin was knocked down in BEAS-2B cells using siRNA. Ezrin phosphorylation levels were measured to determine activation status. The integrity of the airway epithelial barrier was assessed in vivo by characterizing morphological structure, and in vitro in BEAS-2B cells by measuring tight junction protein expression, transepithelial electrical resistance (TER) and permeability. Results We demonstrated that ezrin expression levels were lower in the lung tissue and airway epithelium of diabetic mice than those in control mice. The morphological structure of the airway epithelium was altered in diabetic mice. High glucose levels downregulated the expression and distribution of ezrin and connexin 43, reduced the expression of tight junction proteins, and altered the epithelial barrier characteristics of BEAS-2B cells. Ezrin knockdown had effects similar to those of high glucose levels. Moreover, a specific inhibitor of ezrin Thr567 phosphorylation (NSC305787) inhibited epithelial barrier formation. Conclusion These results demonstrate that ezrin expression and activation are associated with airway epithelial damage in diabetes mellitus. These findings provide new insights into the molecular pathogenesis of pulmonary infections in diabetes mellitus and may lead to novel therapeutic interventions for airway epithelial barrier damage.
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Affiliation(s)
- Hongmei Yu
- Department of Geriatrics, The First Affiliated Hospital of Chongqing Medical University, Chongqing, People’s Republic of China
| | - Cheng Luo
- Department of Geriatrics, The First Affiliated Hospital of Chongqing Medical University, Chongqing, People’s Republic of China
| | - Ru Linghu
- Department of Internal Medicine, Hospital of Chongqing University, Chongqing, People’s Republic of China
| | - Juan Yang
- Department of Respiratory Medicine, Chongqing Hospital of Traditional Chinese Medicine, Chongqing, People’s Republic of China
| | - Haiqiao Wu
- Department of Respiratory Medicine, Chongqing Hospital of Traditional Chinese Medicine, Chongqing, People’s Republic of China
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2
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Guo J, Liu X, Zhao J, Xu H, Gao Z, Wu ZQ, Song YY. Rational design of mesoporous chiral MOFs as reactive pockets in nanochannels for enzyme-free identification of monosaccharide enantiomers. Chem Sci 2023; 14:1742-1751. [PMID: 36819857 PMCID: PMC9930935 DOI: 10.1039/d2sc05784k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Accepted: 01/17/2023] [Indexed: 01/19/2023] Open
Abstract
Monosaccharides play significant roles in daily metabolism in living organisms. Although various devices have been constructed for monosaccharide identification, most rely on the specificity of the natural enzyme. Herein, inspired by natural ionic channels, an asymmetrical MOF-in-nanochannel architecture is developed to discriminate monosaccharide enantiomers based on cascade reactions by combining oxidase-mimicking and Fenton-like catalysis in homochiral mesoporous CuMOF pockets. The identification performance is remarkably enhanced by the increased oxidase-mimicking activity of Au nanoparticles under a local surface plasmon resonance (LSPR) excitation. The apparent steady-state kinetic parameters and nano-fluidic simulation indicate that the different affinities induced by Au-LSPR excitation and the confinement effect from MOF pockets precipitate the high chiral sensitivity. This study offers a promising strategy for designing an enantiomer discrimination device and helps to gain insight into the origin of stereoselectivity in a natural enzyme.
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Affiliation(s)
- Junli Guo
- College of Sciences, Northeastern University Shenyang 110819 China
| | - Xuao Liu
- College of Sciences, Northeastern University Shenyang 110819 China
| | - Junjian Zhao
- College of Sciences, Northeastern University Shenyang 110819 China
| | - Huijie Xu
- College of Sciences, Northeastern University Shenyang 110819 China
| | - Zhida Gao
- College of Sciences, Northeastern University Shenyang 110819 China
| | - Zeng-Qiang Wu
- School of Public Health, Nantong University Nantong 226019 China
| | - Yan-Yan Song
- College of Sciences, Northeastern University Shenyang 110819 China
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3
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Dubovski N, Ben Shoshan-Galeczki Y, Malach E, Niv MY. Taste and chirality: l-glucose sweetness is mediated by TAS1R2/TAS2R3 receptor. Food Chem 2022; 373:131393. [PMID: 34715629 DOI: 10.1016/j.foodchem.2021.131393] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Revised: 09/27/2021] [Accepted: 10/09/2021] [Indexed: 01/14/2023]
Abstract
Naturally occurring sugars usually have d-chirality. While a change in chirality typically affects ligand-receptor interaction, non-caloric l-glucose was reported as sweet for humans. Here we show that l- and d-glucose have similar sensory detection thresholds (0.041 ± 0.006 M for d-glucose, and 0.032 ± 0.007 M for l-glucose) and similar sweetness intensities at suprathreshold concentrations. We demonstrate that l-glucose acts via the sweet taste receptor TAS1R2/TAS1R3, eliciting a dose-dependent activation in cell-based functional assays. Computational docking of glucose to the VFT domain of TAS1R2 suggests two sub-pockets, each compatible with each of the enantiomers. While some polar residues (Y103, D142, N143, S144, Y215) are unique for sub-pocket A and others (D307, T326, E382, R383) for sub-pocket B, no interaction is unique for only one enantiomer. The many options for creating hydrogen bonds with the hydroxyl moieties of glucose explain how both enantiomers can fit each one of the sub-pockets.
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Affiliation(s)
- Nitzan Dubovski
- The Institute of Biochemistry, Food Science and Nutrition, Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, P.O. Box 12, Rehovot 76100, Israel; Fritz Haber Center for Molecular Dynamics, The Hebrew University, Jerusalem, Israel.
| | - Yaron Ben Shoshan-Galeczki
- The Institute of Biochemistry, Food Science and Nutrition, Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, P.O. Box 12, Rehovot 76100, Israel; Fritz Haber Center for Molecular Dynamics, The Hebrew University, Jerusalem, Israel.
| | - Einav Malach
- The Institute of Biochemistry, Food Science and Nutrition, Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, P.O. Box 12, Rehovot 76100, Israel; Fritz Haber Center for Molecular Dynamics, The Hebrew University, Jerusalem, Israel
| | - Masha Y Niv
- The Institute of Biochemistry, Food Science and Nutrition, Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, P.O. Box 12, Rehovot 76100, Israel; Fritz Haber Center for Molecular Dynamics, The Hebrew University, Jerusalem, Israel.
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4
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Martens K, Steelant B, Bullens DMA. Taste Receptors: The Gatekeepers of the Airway Epithelium. Cells 2021; 10:cells10112889. [PMID: 34831117 PMCID: PMC8616034 DOI: 10.3390/cells10112889] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Revised: 10/17/2021] [Accepted: 10/22/2021] [Indexed: 02/07/2023] Open
Abstract
Taste receptors are well known for their role in the sensation of taste. Surprisingly, the expression and involvement of taste receptors in chemosensory processes outside the tongue have been recently identified in many organs including the airways. Currently, a clear understanding of the airway-specific function of these receptors and the endogenous activating/inhibitory ligands is lagging. The focus of this review is on recent physiological and clinical data describing the taste receptors in the airways and their activation by secreted bacterial compounds. Taste receptors in the airways are potentially involved in three different immune pathways (i.e., the production of nitric oxide and antimicrobial peptides secretion, modulation of ciliary beat frequency, and bronchial smooth muscle cell relaxation). Moreover, genetic polymorphisms in these receptors may alter the patients’ susceptibility to certain types of respiratory infections as well as to differential outcomes in patients with chronic inflammatory airway diseases such as chronic rhinosinusitis and asthma. A better understanding of the function of taste receptors in the airways may lead to the development of a novel class of therapeutic molecules that can stimulate airway mucosal immune responses and could treat patients with chronic airway diseases.
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Affiliation(s)
- Katleen Martens
- Allergy and Clinical Immunology Research Group, Department of Microbiology, Immunology and Transplantation, KU Leuven, 3000 Leuven, Belgium; (K.M.); (B.S.)
- Department of Bioscience Engineering, University of Antwerp, 2020 Antwerp, Belgium
| | - Brecht Steelant
- Allergy and Clinical Immunology Research Group, Department of Microbiology, Immunology and Transplantation, KU Leuven, 3000 Leuven, Belgium; (K.M.); (B.S.)
| | - Dominique M. A. Bullens
- Allergy and Clinical Immunology Research Group, Department of Microbiology, Immunology and Transplantation, KU Leuven, 3000 Leuven, Belgium; (K.M.); (B.S.)
- Clinical Division of Pediatrics, University Hospitals Leuven, 3000 Leuven, Belgium
- Correspondence:
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5
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Logette E, Lorin C, Favreau C, Oshurko E, Coggan JS, Casalegno F, Sy MF, Monney C, Bertschy M, Delattre E, Fonta PA, Krepl J, Schmidt S, Keller D, Kerrien S, Scantamburlo E, Kaufmann AK, Markram H. A Machine-Generated View of the Role of Blood Glucose Levels in the Severity of COVID-19. Front Public Health 2021; 9:695139. [PMID: 34395368 PMCID: PMC8356061 DOI: 10.3389/fpubh.2021.695139] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Accepted: 06/30/2021] [Indexed: 01/08/2023] Open
Abstract
SARS-CoV-2 started spreading toward the end of 2019 causing COVID-19, a disease that reached pandemic proportions among the human population within months. The reasons for the spectrum of differences in the severity of the disease across the population, and in particular why the disease affects more severely the aging population and those with specific preconditions are unclear. We developed machine learning models to mine 240,000 scientific articles openly accessible in the CORD-19 database, and constructed knowledge graphs to synthesize the extracted information and navigate the collective knowledge in an attempt to search for a potential common underlying reason for disease severity. The machine-driven framework we developed repeatedly pointed to elevated blood glucose as a key facilitator in the progression of COVID-19. Indeed, when we systematically retraced the steps of the SARS-CoV-2 infection, we found evidence linking elevated glucose to each major step of the life-cycle of the virus, progression of the disease, and presentation of symptoms. Specifically, elevations of glucose provide ideal conditions for the virus to evade and weaken the first level of the immune defense system in the lungs, gain access to deep alveolar cells, bind to the ACE2 receptor and enter the pulmonary cells, accelerate replication of the virus within cells increasing cell death and inducing an pulmonary inflammatory response, which overwhelms an already weakened innate immune system to trigger an avalanche of systemic infections, inflammation and cell damage, a cytokine storm and thrombotic events. We tested the feasibility of the hypothesis by manually reviewing the literature referenced by the machine-generated synthesis, reconstructing atomistically the virus at the surface of the pulmonary airways, and performing quantitative computational modeling of the effects of glucose levels on the infection process. We conclude that elevation in glucose levels can facilitate the progression of the disease through multiple mechanisms and can explain much of the differences in disease severity seen across the population. The study provides diagnostic considerations, new areas of research and potential treatments, and cautions on treatment strategies and critical care conditions that induce elevations in blood glucose levels.
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Affiliation(s)
- Emmanuelle Logette
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL), Geneva, Switzerland
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | - Henry Markram
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL), Geneva, Switzerland
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6
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Bahadoran A, Bezavada L, Smallwood HS. Fueling influenza and the immune response: Implications for metabolic reprogramming during influenza infection and immunometabolism. Immunol Rev 2021; 295:140-166. [PMID: 32320072 DOI: 10.1111/imr.12851] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2019] [Revised: 02/19/2020] [Accepted: 02/24/2020] [Indexed: 12/11/2022]
Abstract
Recent studies support the notion that glycolysis and oxidative phosphorylation are rheostats in immune cells whose bioenergetics have functional outputs in terms of their biology. Specific intrinsic and extrinsic molecular factors function as molecular potentiometers to adjust and control glycolytic to respiratory power output. In many cases, these potentiometers are used by influenza viruses and immune cells to support pathogenesis and the host immune response, respectively. Influenza virus infects the respiratory tract, providing a specific environmental niche, while immune cells encounter variable nutrient concentrations as they migrate in response to infection. Immune cell subsets have distinct metabolic programs that adjust to meet energetic and biosynthetic requirements to support effector functions, differentiation, and longevity in their ever-changing microenvironments. This review details how influenza coopts the host cell for metabolic reprogramming and describes the overlap of these regulatory controls in immune cells whose function and fate are dictated by metabolism. These details are contextualized with emerging evidence of the consequences of influenza-induced changes in metabolic homeostasis on disease progression.
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Affiliation(s)
- Azadeh Bahadoran
- Department of Pediatrics, University of Tennessee Health Science Center, Memphis, TN, USA
| | - Lavanya Bezavada
- Department of Pediatrics, University of Tennessee Health Science Center, Memphis, TN, USA
| | - Heather S Smallwood
- Department of Pediatrics, University of Tennessee Health Science Center, Memphis, TN, USA
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7
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Oliveira TL, Melo IS, Cardoso-Sousa L, Santos IA, El Zoghbi MB, Shimoura CG, Georjutti RP, Castro OW, Goulart LR, Jardim ACG, Cunha TM, Sabino-Silva R. Pathophysiology of SARS-CoV-2 in Lung of Diabetic Patients. Front Physiol 2020; 11:587013. [PMID: 33362575 PMCID: PMC7758507 DOI: 10.3389/fphys.2020.587013] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Accepted: 10/27/2020] [Indexed: 12/11/2022] Open
Abstract
Novel coronavirus disease (COVID-19) is an infectious disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Its impact on patients with comorbidities is clearly related to fatality cases, and diabetes has been linked to one of the most important causes of severity and mortality in SARS-CoV-2 infected patients. Substantial research progress has been made on COVID-19 therapeutics; however, effective treatments remain unsatisfactory. This unmet clinical need is robustly associated with the complexity of pathophysiological mechanisms described for COVID-19. Several key lung pathophysiological mechanisms promoted by SARS-CoV-2 have driven the response in normoglycemic and hyperglycemic subjects. There is sufficient evidence that glucose metabolism pathways in the lung are closely tied to bacterial proliferation, inflammation, oxidative stress, and pro-thrombotic responses, which lead to severe clinical outcomes. It is also likely that SARS-CoV-2 proliferation is affected by glucose metabolism of type I and type II cells. This review summarizes the current understanding of pathophysiology of SARS-CoV-2 in the lung of diabetic patients and highlights the changes in clinical outcomes of COVID-19 in normoglycemic and hyperglycemic conditions.
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Affiliation(s)
- Tales Lyra Oliveira
- Heart Institute, Faculty of Medicine, University of São Paulo, São Paulo, Brazil.,Medical School, Municipal University of São Caetano do Sul, São Paulo, Brazil
| | - Igor Santana Melo
- Institute of Biological Sciences and Health, Federal University of Alagoas, Alagoas, Brazil
| | - Léia Cardoso-Sousa
- Department of Physiology, Institute of Biomedical Sciences, Federal University of Uberlândia, Uberlândia, Brazil
| | - Igor Andrade Santos
- Laboratory of Virology, Institute of Biomedical Sciences, Federal University of Uberlândia, Uberlândia, Brazil
| | | | - Caroline Gusson Shimoura
- Department of Physiology and Anatomy, University of North Texas Health Science Center, Fort Worth, TX, United States
| | - Renata Pereira Georjutti
- Department of Physiology and Anatomy, University of North Texas Health Science Center, Fort Worth, TX, United States
| | - Olagide Wagner Castro
- Institute of Biological Sciences and Health, Federal University of Alagoas, Alagoas, Brazil
| | - Luiz Ricardo Goulart
- Institute of Biotechnology, Federal University of Uberlândia, Uberlândia, Brazil.,Department of Medical Microbiology and Immunology, University of California, Davis, Davis, CA, United States
| | - Ana Carolina Gomes Jardim
- Laboratory of Virology, Institute of Biomedical Sciences, Federal University of Uberlândia, Uberlândia, Brazil
| | - Thúlio Marquez Cunha
- Department of Pulmonology, School of Medicine, Federal University of Uberlândia, Uberlândia, Brazil
| | - Robinson Sabino-Silva
- Department of Physiology, Institute of Biomedical Sciences, Federal University of Uberlândia, Uberlândia, Brazil
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8
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Woodall M, Jacob J, Kalsi KK, Schroeder V, Davis E, Kenyon B, Khan I, Garnett JP, Tarran R, Baines DL. E-cigarette constituents propylene glycol and vegetable glycerin decrease glucose uptake and its metabolism in airway epithelial cells in vitro. Am J Physiol Lung Cell Mol Physiol 2020; 319:L957-L967. [PMID: 32996783 PMCID: PMC7792687 DOI: 10.1152/ajplung.00123.2020] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 09/11/2020] [Accepted: 09/11/2020] [Indexed: 02/07/2023] Open
Abstract
Electronic nicotine delivery systems, or e-cigarettes, utilize a liquid solution that normally contains propylene glycol (PG) and vegetable glycerin (VG) to generate vapor and act as a carrier for nicotine and flavorings. Evidence indicated these "carriers" reduced growth and survival of epithelial cells including those of the airway. We hypothesized that 3% PG or PG mixed with VG (3% PG/VG, 55:45) inhibited glucose uptake in human airway epithelial cells as a first step to reducing airway cell survival. Exposure of H441 or human bronchiolar epithelial cells (HBECs) to PG and PG/VG (30-60 min) inhibited glucose uptake and mitochondrial ATP synthesis. PG/VG inhibited glycolysis. PG/VG and mannitol reduced cell volume and height of air-liquid interface cultures. Mannitol, but not PG/VG, increased phosphorylation of p38 MAPK. PG/VG reduced transepithelial electrical resistance, which was associated with increased transepithelial solute permeability. PG/VG decreased fluorescence recovery after photobleaching of green fluorescent protein-linked glucose transporters GLUT1 and GLUT10, indicating that glucose transport function was compromised. Puffing PG/VG vapor onto the apical surface of primary HBECs for 10 min to mimic the effect of e-cigarette smoking also reduced glucose transport. In conclusion, short-term exposure to PG/VG, key components of e-cigarettes, decreased glucose transport and metabolism in airway cells. We propose that this was a result of PG/VG reduced cell volume and membrane fluidity, with further consequences on epithelial barrier function. Taking these results together, we suggest these factors contribute to reduced defensive properties of the epithelium. We propose that repeated/chronic exposure to these agents are likely to contribute to airway damage in e-cigarette users.
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Affiliation(s)
- M. Woodall
- Institute for Infection and Immunity, St George’s, University of London, Tooting, London, United Kingdom
| | - J. Jacob
- Institute for Infection and Immunity, St George’s, University of London, Tooting, London, United Kingdom
| | - K. K. Kalsi
- Institute for Infection and Immunity, St George’s, University of London, Tooting, London, United Kingdom
| | - V. Schroeder
- Immunology and Respiratory Diseases Research, Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach an der Riss, Germany
| | - E. Davis
- Marsico Lung Institute and Department of Cell Biology and Physiology, University of North Carolina, Chapel Hill, North Carolina
| | - B. Kenyon
- Marsico Lung Institute and Department of Cell Biology and Physiology, University of North Carolina, Chapel Hill, North Carolina
| | - I. Khan
- Institute for Infection and Immunity, St George’s, University of London, Tooting, London, United Kingdom
| | - J. P. Garnett
- Immunology and Respiratory Diseases Research, Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach an der Riss, Germany
| | - R. Tarran
- Marsico Lung Institute and Department of Cell Biology and Physiology, University of North Carolina, Chapel Hill, North Carolina
| | - D. L. Baines
- Institute for Infection and Immunity, St George’s, University of London, Tooting, London, United Kingdom
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9
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Favia M, de Bari L, Bobba A, Atlante A. An Intriguing Involvement of Mitochondria in Cystic Fibrosis. J Clin Med 2019; 8:jcm8111890. [PMID: 31698802 PMCID: PMC6912654 DOI: 10.3390/jcm8111890] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Revised: 10/31/2019] [Accepted: 11/04/2019] [Indexed: 12/16/2022] Open
Abstract
Cystic fibrosis (CF) occurs when the cystic fibrosis transmembrane conductance regulator (CFTR) protein is not synthetized and folded correctly. The CFTR protein helps to maintain the balance of salt and water on many body surfaces, such as the lung surface. When the protein is not working correctly, chloride becomes trapped in cells, then water cannot hydrate the cellular surface and the mucus covering the cells becomes thick and sticky. Furthermore, a defective CFTR appears to produce a redox imbalance in epithelial cells and extracellular fluids and to cause an abnormal generation of reactive oxygen species: as a consequence, oxidative stress has been implicated as a causative factor in the aetiology of the process. Moreover, massive evidences show that defective CFTR gives rise to extracellular GSH level decrease and elevated glucose concentrations in airway surface liquid (ASL), thus encouraging lung infection by pathogens in the CF advancement. Recent research in progress aims to rediscover a possible role of mitochondria in CF. Here the latest new and recent studies on mitochondrial bioenergetics are collected. Surprisingly, they have enabled us to ascertain that mitochondria have a leading role in opposing the high ASL glucose level as well as oxidative stress in CF.
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Affiliation(s)
- Maria Favia
- Istituto di Biomembrane, Bioenergetica e Biotecnologie Molecolari—CNR, Via G. Amendola 122/O, 70126 Bari, Italy; (L.d.B.); (A.B.)
- Dipartimento di Bioscienze, Biotecnologie e Biofarmaceutica, Università di Bari, Via E. Orabona 4, 70126 Bari, Italy
- Correspondence: (M.F.); (A.A.)
| | - Lidia de Bari
- Istituto di Biomembrane, Bioenergetica e Biotecnologie Molecolari—CNR, Via G. Amendola 122/O, 70126 Bari, Italy; (L.d.B.); (A.B.)
| | - Antonella Bobba
- Istituto di Biomembrane, Bioenergetica e Biotecnologie Molecolari—CNR, Via G. Amendola 122/O, 70126 Bari, Italy; (L.d.B.); (A.B.)
| | - Anna Atlante
- Istituto di Biomembrane, Bioenergetica e Biotecnologie Molecolari—CNR, Via G. Amendola 122/O, 70126 Bari, Italy; (L.d.B.); (A.B.)
- Correspondence: (M.F.); (A.A.)
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10
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Bearham J, Garnett JP, Schroeder V, Biggart MGS, Baines DL. Effective glucose metabolism maintains low intracellular glucose in airway epithelial cells after exposure to hyperglycemia. Am J Physiol Cell Physiol 2019; 317:C983-C992. [PMID: 31433692 PMCID: PMC6879884 DOI: 10.1152/ajpcell.00193.2019] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Revised: 07/26/2019] [Accepted: 08/13/2019] [Indexed: 02/07/2023]
Abstract
The airway epithelium maintains differential glucose concentrations between the airway surface liquid (ASL, ~0.4 mM) and the blood/interstitium (5-6 mM), which is important for defense against infection. Glucose primarily moves from the blood to the ASL via paracellular movement, down its concentration gradient, across the tight junctions. However, there is evidence that glucose can move transcellularly across epithelial cells. Using a Förster resonance energy transfer sensor for glucose, we investigated intracellular glucose concentrations in airway epithelial cells and the role of hexokinases in regulating intracellular glucose concentrations in normoglycemic and hyperglycemic conditions. Our findings indicated that in airway epithelial cells (H441 or primary human bronchial epithelial cells) exposed to 5 mM glucose (normoglycemia), intracellular glucose concentration is in the micromolar range. Inhibition of facilitative glucose transporters (GLUTs) with cytochalasin B reduced intracellular glucose concentration. When cells were exposed to 15 mM glucose (hyperglycemia), intracellular glucose concentration was reduced. Airway cells expressed hexokinases I, II, and III. Inhibition with 3-bromopyruvate decreased hexokinase activity by 25% and elevated intracellular glucose concentration, but levels remained in the micromolar range. Exposure to hyperglycemia increased glycolysis, glycogen, and sorbitol. Thus, glucose enters the airway cell via GLUTs and is then rapidly processed by hexokinase-dependent and hexokinase-independent metabolic pathways to maintain low intracellular glucose concentrations. We propose that this prevents transcellular transport and aids the removal of glucose from the ASL and that the main route of entry for glucose into the ASL is via the paracellular pathway.
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Affiliation(s)
- Jade Bearham
- Institute for Infection and Immunity, St. George's University of London, London, United Kingdom
| | - James P Garnett
- Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne, United Kingdom
- Immunology and Respiratory Diseases Research, Boehringer Ingelheim Pharma and Company, Biberach an der Riss, Germany
| | - Victoria Schroeder
- Immunology and Respiratory Diseases Research, Boehringer Ingelheim Pharma and Company, Biberach an der Riss, Germany
| | - Matthew G S Biggart
- Institute for Infection and Immunity, St. George's University of London, London, United Kingdom
| | - Deborah L Baines
- Institute for Infection and Immunity, St. George's University of London, London, United Kingdom
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11
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Dai W, Wang H, Zhou Q, Li D, Feng X, Yang Z, Wang W, Qiu C, Lu Z, Xu X, Lyu M, Xie G, Li Y, Bao Y, Liu Y, Shen K, Yao K, Feng X, Yang Y, Zhou K, Li S, Zheng Y. An integrated respiratory microbial gene catalogue to better understand the microbial aetiology of Mycoplasma pneumoniae pneumonia. Gigascience 2019; 8:giz093. [PMID: 31367746 PMCID: PMC6669060 DOI: 10.1093/gigascience/giz093] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Revised: 05/31/2019] [Accepted: 07/10/2019] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND The imbalanced respiratory microbiota observed in pneumonia causes high morbidity and mortality in childhood. Respiratory metagenomic analysis demands a comprehensive microbial gene catalogue, which will significantly advance our understanding of host-microorganism interactions. RESULTS We collected 334 respiratory microbial samples from 171 healthy children and 76 children with pneumonia. The respiratory microbial gene catalogue we established comprised 2.25 million non-redundant microbial genes, covering 90.52% of prevalent genes. The major oropharyngeal microbial species found in healthy children were Prevotella and Streptococcus. In children with Mycoplasma pneumoniae pneumonia (MPP), oropharyngeal microbial diversity and associated gene numbers decreased compared with those of healthy children. The concurrence network of oropharyngeal microorganisms in patients predominantly featured Staphylococcus spp. and M. pneumoniae. Functional orthologues, which are associated with the metabolism of various lipids, membrane transport, and signal transduction, accumulated in the oropharyngeal microbiome of children with pneumonia. Several antibiotic resistance genes and virulence factor genes were identified in the genomes of M. pneumoniae and 13 other microorganisms reconstructed via metagenomic data. Although the common macrolide/β-lactam resistance genes were not identified in the assembled M. pneumoniae genome, a single-nucleotide polymorphism (A2063G) related to macrolide resistance was identified in a 23S ribosomal RNA gene. CONCLUSIONS The results of this study will facilitate exploration of unknown microbial components and host-microorganism interactions in studies of the respiratory microbiome. They will also yield further insights into the microbial aetiology of MPP.
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Affiliation(s)
- Wenkui Dai
- Department of Computer Science, City University of Hong Kong, Hong Kong 999077, China
| | - Heping Wang
- Department of Respiratory Diseases, Shenzhen Children’s Hospital, Shenzhen 518026, China
| | - Qian Zhou
- Department of Microbial Research, WeHealthGene Institute, Shenzhen 518000, China
| | - Dongfang Li
- Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, No. 1037 Luoyu Road, Wuhan 430074, China
| | - Xin Feng
- Department of Microbial Research, WeHealthGene Institute, Shenzhen 518000, China
| | - Zhenyu Yang
- Department of Microbial Research, WeHealthGene Institute, Shenzhen 518000, China
| | - Wenjian Wang
- Department of Respiratory Diseases, Shenzhen Children’s Hospital, Shenzhen 518026, China
| | - Chuangzhao Qiu
- Department of Microbial Research, WeHealthGene Institute, Shenzhen 518000, China
| | - Zhiwei Lu
- Department of Respiratory Diseases, Shenzhen Children’s Hospital, Shenzhen 518026, China
| | - Ximing Xu
- Institute of Statistics, Nankai University, No. 94 Weijin Road, Tianjin 300071, China
| | - Mengxuan Lyu
- Department of Computer Science, City University of Hong Kong, Hong Kong 999077, China
| | - Gan Xie
- Department of Respiratory Diseases, Shenzhen Children’s Hospital, Shenzhen 518026, China
| | - Yinhu Li
- Department of Microbial Research, WeHealthGene Institute, Shenzhen 518000, China
| | - Yanmin Bao
- Department of Respiratory Diseases, Shenzhen Children’s Hospital, Shenzhen 518026, China
| | - Yanhong Liu
- Department of Microbial Research, WeHealthGene Institute, Shenzhen 518000, China
| | - Kunling Shen
- Department of Respiratory Diseases, Shenzhen Children’s Hospital, Shenzhen 518026, China
- Department of Respiratory Diseases, Beijing Children's Hospital, Beijing 100045, China
| | - Kaihu Yao
- Department of Respiratory Diseases, Shenzhen Children’s Hospital, Shenzhen 518026, China
- Department of Respiratory Diseases, Beijing Children's Hospital, Beijing 100045, China
| | - Xikang Feng
- Department of Computer Science, City University of Hong Kong, Hong Kong 999077, China
| | - Yonghong Yang
- Department of Respiratory Diseases, Shenzhen Children’s Hospital, Shenzhen 518026, China
- Department of Microbial Research, WeHealthGene Institute, Shenzhen 518000, China
- Department of Respiratory Diseases, Beijing Children's Hospital, Beijing 100045, China
| | - Ke Zhou
- Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, No. 1037 Luoyu Road, Wuhan 430074, China
| | - Shuaicheng Li
- Department of Computer Science, City University of Hong Kong, Hong Kong 999077, China
| | - Yuejie Zheng
- Department of Respiratory Diseases, Shenzhen Children’s Hospital, Shenzhen 518026, China
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12
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Modulation of glucose-related metabolic pathways controls glucose level in airway surface liquid and fight oxidative stress in cystic fibrosis cells. J Bioenerg Biomembr 2019; 51:203-218. [PMID: 31030390 DOI: 10.1007/s10863-019-09797-5] [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: 12/06/2018] [Accepted: 04/09/2019] [Indexed: 10/26/2022]
Abstract
Direct and indirect evidences show that elevated glucose concentrations in airway surface liquid (ASL) promote lung infection by pathogens, playing a role in the progression of the Cystic Fibrosis (CF) disease. The joint action of transporter/s for glucose and of the cellular enzymes is essential in order to try to lower ASL glucose level. Inside the cell, the glycolysis and the pentose phosphate pathway (PPP) compete for the utilization of glucose-6-phosphate (G6P), the product in which glucose, after entry within the cell and phosphorylation, is trapped. The study aims to clarify whether, modulating the activity of enzymatic proteins and/or the level of metabolites/cofactors, involved in intracellular glucose utilization, a lowering of the extracellular glucose level in CF occurs. Biochemical approaches have enabled us to understand i) how G6P is shunted between glycolysis and PPP and ii) that mitochondria, more than enzymes/cofactors participating to the two cell glucose utilization pathways, are protagonists of the scene in counteracting the high ASL glucose level as well as oxidative stress in CF.
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13
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The Role of Taste Receptors in Airway Innate Immune Defense. SINUSITIS 2018. [DOI: 10.3390/sinusitis3020006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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14
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Hsu IL, Lu CL, Li CC, Tsai SH, Chen CZ, Hu SC, Li CY. Population-based cohort study suggesting a significantly increased risk of developing chronic obstructive pulmonary disease in people with type 2 diabetes mellitus. Diabetes Res Clin Pract 2018; 138:66-74. [PMID: 29408706 DOI: 10.1016/j.diabres.2018.01.037] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Revised: 01/05/2018] [Accepted: 01/30/2018] [Indexed: 01/04/2023]
Abstract
AIMS To investigate whether type 2 diabetes mellitus (T2DM) increases the risk of developing chronic obstructive pulmonary disease (COPD). METHODS This population-based cohort study used Taiwan's National Health insurance claim data to investigate the association of T2DM with the risk of COPD. A total of 716,623 pairs of people (patients with T2DM and their age-, sex-, and calendar year-matched controls) were identified in 2002-2003 and were followed until the occurrence of newly-diagnosed COPD or the end of 2011. Cox proportional hazard models were used to relate COPD incidence to T2DM. RESULTS People with T2DM experienced a higher incidence rate of COPD than controls (159.6 vs 122.7 per 104 person-years). After controlling for confounders, T2DM significantly increased the hazard of COPD (hazard ratio [HR] = 1.15, 95% confidence interval = 1.14-1.16). Stratified analysis indicated that the association between T2DM and COPD was slightly greater in women than in men (HR, 1.15 vs. 1.11) and in people aged <65 years than in people aged ≥65 years (HR, 1.17 vs. 1.05 in men; 1.16 vs. 1.13 in women). CONCLUSIONS Our findings demonstrated a modest association of T2DM with the risk of developing COPD, possibly shedding light into the adverse effects of hyperglycemia on pulmonary function.
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Affiliation(s)
- I-Lin Hsu
- Department of Public Health, College of Medicine, National Cheng Kung University, Tainan, Taiwan; Department of Emergency Medicine, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Chin-Li Lu
- Department of Public Health, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Chia-Chun Li
- Department of Public Health, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Sheng-Han Tsai
- Division of Chest Medicine, Department of Internal Medicine, College of Medicine and Hospital, National Cheng Kung University, Tainan, Taiwan
| | - Chiung-Zuei Chen
- Division of Chest Medicine, Department of Internal Medicine, College of Medicine and Hospital, National Cheng Kung University, Tainan, Taiwan
| | - Susan C Hu
- Department of Public Health, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Chung-Yi Li
- Department of Public Health, College of Medicine, National Cheng Kung University, Tainan, Taiwan; Department of Public Health, College of Public Health, China Medical University, Taichung, Taiwan.
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15
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Airway Glucose Homeostasis. Chest 2018; 153:507-514. [DOI: 10.1016/j.chest.2017.05.031] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Revised: 05/12/2017] [Accepted: 05/25/2017] [Indexed: 01/19/2023] Open
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16
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Lee RJ, Hariri BM, McMahon DB, Chen B, Doghramji L, Adappa ND, Palmer JN, Kennedy DW, Jiang P, Margolskee RF, Cohen NA. Bacterial d-amino acids suppress sinonasal innate immunity through sweet taste receptors in solitary chemosensory cells. Sci Signal 2017; 10:10/495/eaam7703. [PMID: 28874606 DOI: 10.1126/scisignal.aam7703] [Citation(s) in RCA: 78] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
In the upper respiratory epithelium, bitter and sweet taste receptors present in solitary chemosensory cells influence antimicrobial innate immune defense responses. Whereas activation of bitter taste receptors (T2Rs) stimulates surrounding epithelial cells to release antimicrobial peptides, activation of the sweet taste receptor (T1R) in the same cells inhibits this response. This mechanism is thought to control the magnitude of antimicrobial peptide release based on the sugar content of airway surface liquid. We hypothesized that d-amino acids, which are produced by various bacteria and activate T1R in taste receptor cells in the mouth, may also activate T1R in the airway. We showed that both the T1R2 and T1R3 subunits of the sweet taste receptor (T1R2/3) were present in the same chemosensory cells of primary human sinonasal epithelial cultures. Respiratory isolates of Staphylococcus species, but not Pseudomonas aeruginosa, produced at least two d-amino acids that activate the sweet taste receptor. In addition to inhibiting P. aeruginosa biofilm formation, d-amino acids derived from Staphylococcus inhibited T2R-mediated signaling and defensin secretion in sinonasal cells by activating T1R2/3. d-Amino acid-mediated activation of T1R2/3 also enhanced epithelial cell death during challenge with Staphylococcus aureus in the presence of the bitter receptor-activating compound denatonium benzoate. These data establish a potential mechanism for interkingdom signaling in the airway mediated by bacterial d-amino acids and the mammalian sweet taste receptor in airway chemosensory cells.
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Affiliation(s)
- Robert J Lee
- Department of Otorhinolaryngology-Head and Neck Surgery, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA. .,Department of Physiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Benjamin M Hariri
- Department of Otorhinolaryngology-Head and Neck Surgery, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Derek B McMahon
- Department of Otorhinolaryngology-Head and Neck Surgery, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Bei Chen
- Department of Otorhinolaryngology-Head and Neck Surgery, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Laurel Doghramji
- Department of Otorhinolaryngology-Head and Neck Surgery, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Nithin D Adappa
- Department of Otorhinolaryngology-Head and Neck Surgery, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - James N Palmer
- Department of Otorhinolaryngology-Head and Neck Surgery, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - David W Kennedy
- Department of Otorhinolaryngology-Head and Neck Surgery, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Peihua Jiang
- Monell Chemical Senses Center, Philadelphia, PA 19104, USA
| | | | - Noam A Cohen
- Department of Otorhinolaryngology-Head and Neck Surgery, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA. .,Monell Chemical Senses Center, Philadelphia, PA 19104, USA.,Philadelphia Veterans Affairs Medical Center Surgical Service, Philadelphia, PA 19104, USA
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17
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He L, Zhou X, Huang N, Li H, Cui Z, Tian J, Jiang Q, Liu S, Wu J, Li T, Yao K, Yin Y. Administration of alpha-ketoglutarate improves epithelial restitution under stress injury in early-weaning piglets. Oncotarget 2017; 8:91965-91978. [PMID: 29190890 PMCID: PMC5696156 DOI: 10.18632/oncotarget.20555] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Accepted: 08/07/2017] [Indexed: 12/21/2022] Open
Abstract
Alpha-ketoglutarate (AKG) is an important cellular metabolite that participates in energy production and amino acid metabolism. However, the protective effects and mechanism of AKG on mucosal lesions have not been well understood. This study was conducted to investigate the effects of dietary AKG supplementation on epithelial restitution in early-weaning piglets under Escherichia coli lipopolysaccharide (LPS) induction. A total of 32 weaned piglets were used in a 2 × 2 factorial design; the major factors were dietary treatment (basal diet or AKG diet) and inflammatory challenge (LPS or saline). The results showed that AKG supplementation improved the growth performance and intestinal morphology in the LPS-induced early-weaning piglets. Compared with the basal diet, the AKG diet remarkably decreased the concentration and mRNA expression of intestinal inflammatory cytokines (IL-1β, IL-6, and IL-12) in the LPS-induced piglets. Moreover, AKG administration upregulated the mRNA expression of nutrient-sensing transporters (GLUT-2, SGLT-1, PEPT-1, I-FABP2) in the small intestine of both saline- and LPS-treated piglets, and improved the distribution and expression of tight-junction genes andproteins (ZO-1, Occludin, Claudins, E-cadherin). Collectively, our findings indicate that AKG has the potential to alleviate intestinal inflammatory response and improve epithelial restitution and nutrient-sensing ability under stress injury in early-weaning piglets, and it also provides an experimental basis for enteral use of AKG in swine production and clinical application to prevent intestinal epithelial damage.
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Affiliation(s)
- Liuqin He
- Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Scientific Observing and Experimental Station of Animal Nutrition and Feed Science in South-Central, Ministry of Agriculture, Hunan Provincial Engineering Research Center for Healthy Livestock and Poultry Production, Changsha, Hunan 410125, China.,University of Chinese Academy of Sciences, Beijing, 10039, China
| | - Xihong Zhou
- Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Scientific Observing and Experimental Station of Animal Nutrition and Feed Science in South-Central, Ministry of Agriculture, Hunan Provincial Engineering Research Center for Healthy Livestock and Poultry Production, Changsha, Hunan 410125, China
| | - Niu Huang
- College of Animal Science and Technology, Hunan Agricultural University, Changsha, Hunan, 410128, China
| | - Huan Li
- College of Animal Science and Technology, Hunan Agricultural University, Changsha, Hunan, 410128, China
| | - Zhijie Cui
- Xiangtan University, Xiangtan, Hunan 411105, China
| | - Junquan Tian
- Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Scientific Observing and Experimental Station of Animal Nutrition and Feed Science in South-Central, Ministry of Agriculture, Hunan Provincial Engineering Research Center for Healthy Livestock and Poultry Production, Changsha, Hunan 410125, China.,University of Chinese Academy of Sciences, Beijing, 10039, China
| | - Qian Jiang
- Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Scientific Observing and Experimental Station of Animal Nutrition and Feed Science in South-Central, Ministry of Agriculture, Hunan Provincial Engineering Research Center for Healthy Livestock and Poultry Production, Changsha, Hunan 410125, China.,University of Chinese Academy of Sciences, Beijing, 10039, China
| | - Shaojuan Liu
- Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Scientific Observing and Experimental Station of Animal Nutrition and Feed Science in South-Central, Ministry of Agriculture, Hunan Provincial Engineering Research Center for Healthy Livestock and Poultry Production, Changsha, Hunan 410125, China.,University of Chinese Academy of Sciences, Beijing, 10039, China
| | - Jian Wu
- Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Scientific Observing and Experimental Station of Animal Nutrition and Feed Science in South-Central, Ministry of Agriculture, Hunan Provincial Engineering Research Center for Healthy Livestock and Poultry Production, Changsha, Hunan 410125, China.,University of Chinese Academy of Sciences, Beijing, 10039, China
| | - Tiejun Li
- Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Scientific Observing and Experimental Station of Animal Nutrition and Feed Science in South-Central, Ministry of Agriculture, Hunan Provincial Engineering Research Center for Healthy Livestock and Poultry Production, Changsha, Hunan 410125, China.,Hunan Co-Innovation Center of Animal Production Safety, Changsha, Hunan, 410128, China
| | - Kang Yao
- Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Scientific Observing and Experimental Station of Animal Nutrition and Feed Science in South-Central, Ministry of Agriculture, Hunan Provincial Engineering Research Center for Healthy Livestock and Poultry Production, Changsha, Hunan 410125, China.,Hunan Co-Innovation Center of Animal Production Safety, Changsha, Hunan, 410128, China
| | - Yulong Yin
- Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Scientific Observing and Experimental Station of Animal Nutrition and Feed Science in South-Central, Ministry of Agriculture, Hunan Provincial Engineering Research Center for Healthy Livestock and Poultry Production, Changsha, Hunan 410125, China.,Hunan Co-Innovation Center of Animal Production Safety, Changsha, Hunan, 410128, China.,Laboratory of Animal Nutrition and Human Health, College of Life Sciences, Hunan Normal University, Changsha, Hunan, 410006, China
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18
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Molina SA, Moriarty HK, Infield DT, Imhoff BR, Vance RJ, Kim AH, Hansen JM, Hunt WR, Koval M, McCarty NA. Insulin signaling via the PI3-kinase/Akt pathway regulates airway glucose uptake and barrier function in a CFTR-dependent manner. Am J Physiol Lung Cell Mol Physiol 2017; 312:L688-L702. [PMID: 28213469 PMCID: PMC5451595 DOI: 10.1152/ajplung.00364.2016] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2016] [Revised: 02/07/2017] [Accepted: 02/08/2017] [Indexed: 12/13/2022] Open
Abstract
Cystic fibrosis-related diabetes is the most common comorbidity associated with cystic fibrosis (CF) and correlates with increased rates of lung function decline. Because glucose is a nutrient present in the airways of patients with bacterial airway infections and because insulin controls glucose metabolism, the effect of insulin on CF airway epithelia was investigated to determine the role of insulin receptors and glucose transport in regulating glucose availability in the airway. The response to insulin by human airway epithelial cells was characterized by quantitative PCR, immunoblot, immunofluorescence, and glucose uptake assays. Phosphatidylinositol 3-kinase/protein kinase B (Akt) signaling and cystic fibrosis transmembrane conductance regulator (CFTR) activity were analyzed by pharmacological and immunoblot assays. We found that normal human primary airway epithelial cells expressed glucose transporter 4 and that application of insulin stimulated cytochalasin B-inhibitable glucose uptake, consistent with a requirement for glucose transporter translocation. Application of insulin to normal primary human airway epithelial cells promoted airway barrier function as demonstrated by increased transepithelial electrical resistance and decreased paracellular flux of small molecules. This provides the first demonstration that airway cells express insulin-regulated glucose transporters that act in concert with tight junctions to form an airway glucose barrier. However, insulin failed to increase glucose uptake or decrease paracellular flux of small molecules in human airway epithelia expressing F508del-CFTR. Insulin stimulation of Akt1 and Akt2 signaling in CF airway cells was diminished compared with that observed in airway cells expressing wild-type CFTR. These results indicate that the airway glucose barrier is regulated by insulin and is dysfunctional in CF.
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Affiliation(s)
- Samuel A Molina
- Emory+Children's Center for Cystic Fibrosis and Airways Disease Research, Emory University School of Medicine and Children's Healthcare of Atlanta, Atlanta, Georgia;
- Division of Pulmonary, Allergy, Critical Care and Sleep Medicine, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia
| | - Hannah K Moriarty
- Division of Pulmonary, Allergy, Critical Care and Sleep Medicine, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia
| | - Daniel T Infield
- Emory+Children's Center for Cystic Fibrosis and Airways Disease Research, Emory University School of Medicine and Children's Healthcare of Atlanta, Atlanta, Georgia
- Division of Pulmonology, Allergy & Immunology, Cystic Fibrosis and Sleep, Department of Pediatrics, Emory University School of Medicine, Atlanta, Georgia; and
| | - Barry R Imhoff
- Emory+Children's Center for Cystic Fibrosis and Airways Disease Research, Emory University School of Medicine and Children's Healthcare of Atlanta, Atlanta, Georgia
- Division of Pulmonology, Allergy & Immunology, Cystic Fibrosis and Sleep, Department of Pediatrics, Emory University School of Medicine, Atlanta, Georgia; and
| | - Rachel J Vance
- Emory+Children's Center for Cystic Fibrosis and Airways Disease Research, Emory University School of Medicine and Children's Healthcare of Atlanta, Atlanta, Georgia
- Division of Pulmonary, Allergy, Critical Care and Sleep Medicine, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia
| | - Agnes H Kim
- Division of Pulmonary, Allergy, Critical Care and Sleep Medicine, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia
| | - Jason M Hansen
- Emory+Children's Center for Cystic Fibrosis and Airways Disease Research, Emory University School of Medicine and Children's Healthcare of Atlanta, Atlanta, Georgia
| | - William R Hunt
- Emory+Children's Center for Cystic Fibrosis and Airways Disease Research, Emory University School of Medicine and Children's Healthcare of Atlanta, Atlanta, Georgia
- Division of Pulmonary, Allergy, Critical Care and Sleep Medicine, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia
| | - Michael Koval
- Emory+Children's Center for Cystic Fibrosis and Airways Disease Research, Emory University School of Medicine and Children's Healthcare of Atlanta, Atlanta, Georgia
- Division of Pulmonary, Allergy, Critical Care and Sleep Medicine, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia
- Department of Cell Biology, Emory University School of Medicine, Atlanta, Georgia
| | - Nael A McCarty
- Emory+Children's Center for Cystic Fibrosis and Airways Disease Research, Emory University School of Medicine and Children's Healthcare of Atlanta, Atlanta, Georgia
- Division of Pulmonology, Allergy & Immunology, Cystic Fibrosis and Sleep, Department of Pediatrics, Emory University School of Medicine, Atlanta, Georgia; and
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19
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Taste Receptors Mediate Sinonasal Immunity and Respiratory Disease. Int J Mol Sci 2017; 18:ijms18020437. [PMID: 28218655 PMCID: PMC5343971 DOI: 10.3390/ijms18020437] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2016] [Revised: 02/11/2017] [Accepted: 02/12/2017] [Indexed: 02/07/2023] Open
Abstract
The bitter taste receptor T2R38 has been shown to play a role in the pathogenesis of chronic rhinosinusitis (CRS), where the receptor functions to enhance upper respiratory innate immunity through a triad of beneficial immune responses. Individuals with a functional version of T2R38 are tasters for the bitter compound phenylthiocarbamide (PTC) and exhibit an anti-microbial response in the upper airway to certain invading pathogens, while those individuals with a non-functional version of the receptor are PTC non-tasters and lack this beneficial response. The clinical ramifications are significant, with the non-taster genotype being an independent risk factor for CRS requiring surgery, poor quality-of-life (QOL) improvements post-operatively, and decreased rhinologic QOL in patients with cystic fibrosis. Furthermore, indirect evidence suggests that non-tasters also have a larger burden of biofilm formation. This new data may influence the clinical management of patients with infectious conditions affecting the upper respiratory tract and possibly at other mucosal sites throughout the body.
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20
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Carey RM, Adappa ND, Palmer JN, Lee RJ, Cohen NA. Taste Receptors: Regulators of Sinonasal Innate Immunity. Laryngoscope Investig Otolaryngol 2016; 1:88-95. [PMID: 27819057 PMCID: PMC5089074 DOI: 10.1002/lio2.26] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Taste receptors in the oral cavity guide our preferences for foods, preventing toxic ingestions and encouraging proper nutrient consumption. More recently, expression of taste receptors has been demonstrated in other locations throughout the body, including the airway, gastrointestinal tract, pancreas, and brain. The extent and specific roles of extraoral taste receptors are largely unknown, but a growing body of evidence suggests that taste receptors in the airway serve a critical role in sensing bacteria and regulating innate immunity. This review will focus on the function of bitter and sweet taste receptors in the human airway, with particular emphasis on T2R38, a bitter taste receptor found in sinonasal ciliated cells, and the bitter and sweet receptors found on specialized sinonasal solitary chemosensory cells. The importance of these novel taste receptor‐immune circuits in the human airway and their clinical relevance in airway disease will also be reviewed.
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Affiliation(s)
- Ryan M Carey
- Department of Otorhinolaryngology, Perelman School of Medicine, University of Pennsylvania, Ravdin Building, 5 floor, Philadelphia, PA 19104
| | - Nithin D Adappa
- Department of Otorhinolaryngology, Perelman School of Medicine, University of Pennsylvania, Ravdin Building, 5 floor, Philadelphia, PA 19104
| | - James N Palmer
- Department of Otorhinolaryngology, Perelman School of Medicine, University of Pennsylvania, Ravdin Building, 5 floor, Philadelphia, PA 19104
| | - Robert J Lee
- Department of Otorhinolaryngology, Perelman School of Medicine, University of Pennsylvania, Ravdin Building, 5 floor, Philadelphia, PA 19104
| | - Noam A Cohen
- Department of Otorhinolaryngology, Perelman School of Medicine, University of Pennsylvania, Ravdin Building, 5 floor, Philadelphia, PA 19104
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21
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Gill SK, Hui K, Farne H, Garnett JP, Baines DL, Moore LS, Holmes AH, Filloux A, Tregoning JS. Increased airway glucose increases airway bacterial load in hyperglycaemia. Sci Rep 2016; 6:27636. [PMID: 27273266 PMCID: PMC4897689 DOI: 10.1038/srep27636] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2015] [Accepted: 05/19/2016] [Indexed: 01/15/2023] Open
Abstract
Diabetes is associated with increased frequency of hospitalization due to bacterial lung infection. We hypothesize that increased airway glucose caused by hyperglycaemia leads to increased bacterial loads. In critical care patients, we observed that respiratory tract bacterial colonisation is significantly more likely when blood glucose is high. We engineered mutants in genes affecting glucose uptake and metabolism (oprB, gltK, gtrS and glk) in Pseudomonas aeruginosa, strain PAO1. These mutants displayed attenuated growth in minimal medium supplemented with glucose as the sole carbon source. The effect of glucose on growth in vivo was tested using streptozocin-induced, hyperglycaemic mice, which have significantly greater airway glucose. Bacterial burden in hyperglycaemic animals was greater than control animals when infected with wild type but not mutant PAO1. Metformin pre-treatment of hyperglycaemic animals reduced both airway glucose and bacterial load. These data support airway glucose as a critical determinant of increased bacterial load during diabetes.
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Affiliation(s)
- Simren K. Gill
- Mucosal Infection & Immunity Group, Section of Virology, Imperial College London, St Mary’s Campus, London, W2 1PG, UK
- MRC Centre for Molecular Bacteriology and Infection, Department of Life Sciences, Imperial College London, London, SW7 2AZ, UK
| | - Kailyn Hui
- MRC Centre for Molecular Bacteriology and Infection, Department of Life Sciences, Imperial College London, London, SW7 2AZ, UK
| | - Hugo Farne
- Airway Disease Infection Section, National Heart & Lung Institute, Imperial College London, London, W2 1PG, UK
| | - James P. Garnett
- Institute for Infection and Immunity, St George’s, University of London, London SW17 0RE, UK
| | - Deborah L. Baines
- Institute for Infection and Immunity, St George’s, University of London, London SW17 0RE, UK
| | - Luke S.P. Moore
- Health Protection Research Unit in Healthcare Associated Infection and Antimicrobial Resistance, Imperial College London, Hammersmith Campus, London W12 0HS, UK
| | - Alison H. Holmes
- Health Protection Research Unit in Healthcare Associated Infection and Antimicrobial Resistance, Imperial College London, Hammersmith Campus, London W12 0HS, UK
| | - Alain Filloux
- MRC Centre for Molecular Bacteriology and Infection, Department of Life Sciences, Imperial College London, London, SW7 2AZ, UK
| | - John S. Tregoning
- Mucosal Infection & Immunity Group, Section of Virology, Imperial College London, St Mary’s Campus, London, W2 1PG, UK
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22
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Identification of a major IP5 kinase in Cryptococcus neoformans confirms that PP-IP5/IP7, not IP6, is essential for virulence. Sci Rep 2016; 6:23927. [PMID: 27033523 PMCID: PMC4817067 DOI: 10.1038/srep23927] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2016] [Accepted: 03/15/2016] [Indexed: 01/15/2023] Open
Abstract
Fungal inositol polyphosphate (IP) kinases catalyse phosphorylation of IP3 to inositol pyrophosphate, PP-IP5/IP7, which is essential for virulence of Cryptococcus neoformans. Cryptococcal Kcs1 converts IP6 to PP-IP5/IP7, but the kinase converting IP5 to IP6 is unknown. Deletion of a putative IP5 kinase-encoding gene (IPK1) alone (ipk1Δ), and in combination with KCS1 (ipk1Δkcs1Δ), profoundly reduced virulence in mice. However, deletion of KCS1 and IPK1 had a greater impact on virulence attenuation than that of IPK1 alone. ipk1Δkcs1Δ and kcs1Δ lung burdens were also lower than those of ipk1Δ. Unlike ipk1Δ, ipk1Δkcs1Δ and kcs1Δ failed to disseminate to the brain. IP profiling confirmed Ipk1 as the major IP5 kinase in C. neoformans: ipk1Δ produced no IP6 or PP-IP5/IP7 and, in contrast to ipk1Δkcs1Δ, accumulated IP5 and its pyrophosphorylated PP-IP4 derivative. Kcs1 is therefore a dual specificity (IP5 and IP6) kinase producing PP-IP4 and PP-IP5/IP7. All mutants were similarly attenuated in virulence phenotypes including laccase, urease and growth under oxidative/nitrosative stress. Alternative carbon source utilisation was also reduced significantly in all mutants except ipk1Δ, suggesting that PP-IP4 partially compensates for absent PP-IP5/IP7 in ipk1Δ grown under this condition. In conclusion, PP-IP5/IP7, not IP6, is essential for fungal virulence.
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Workman AD, Palmer JN, Adappa ND, Cohen NA. The Role of Bitter and Sweet Taste Receptors in Upper Airway Immunity. Curr Allergy Asthma Rep 2016; 15:72. [PMID: 26492878 DOI: 10.1007/s11882-015-0571-8] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Over the past several years, taste receptors have emerged as key players in the regulation of innate immune defenses in the mammalian respiratory tract. Several cell types in the airway, including ciliated epithelial cells, solitary chemosensory cells, and bronchial smooth muscle cells, all display chemoresponsive properties that utilize taste receptors. A variety of bitter products secreted by microbes are detected with resultant downstream inflammation, increased mucous clearance, antimicrobial peptide secretion, and direct bacterial killing. Genetic variation of bitter taste receptors also appears to play a role in the susceptibility to infection in respiratory disease states, including that of chronic rhinosinusitis. Ongoing taste receptor research may yield new therapeutics that harness innate immune defenses in the respiratory tract and may offer alternatives to antibiotic treatment. The present review discusses taste receptor-protective responses and analyzes the role these receptors play in mediating airway immune function.
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Affiliation(s)
- Alan D Workman
- Department of Otorhinolaryngology: Head and Neck Surgery, University of Pennsylvania Medical Center, 5th Floor Ravdin Building, 3400 Spruce Street, Philadelphia, PA, 19104, USA.,Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - James N Palmer
- Department of Otorhinolaryngology: Head and Neck Surgery, University of Pennsylvania Medical Center, 5th Floor Ravdin Building, 3400 Spruce Street, Philadelphia, PA, 19104, USA.,Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - Nithin D Adappa
- Department of Otorhinolaryngology: Head and Neck Surgery, University of Pennsylvania Medical Center, 5th Floor Ravdin Building, 3400 Spruce Street, Philadelphia, PA, 19104, USA.,Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - Noam A Cohen
- Department of Otorhinolaryngology: Head and Neck Surgery, University of Pennsylvania Medical Center, 5th Floor Ravdin Building, 3400 Spruce Street, Philadelphia, PA, 19104, USA. .,Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA. .,Monell Smell and Taste Center, Philadelphia, PA, USA. .,Philadelphia Veterans Affairs Medical Center, Philadelphia, PA, USA.
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SGLT1 activity in lung alveolar cells of diabetic rats modulates airway surface liquid glucose concentration and bacterial proliferation. Sci Rep 2016; 6:21752. [PMID: 26902517 PMCID: PMC4763199 DOI: 10.1038/srep21752] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Accepted: 01/27/2016] [Indexed: 01/23/2023] Open
Abstract
High glucose concentration in the airway surface liquid (ASL) is an important feature of diabetes that predisposes to respiratory infections. We investigated the role of alveolar epithelial SGLT1 activity on ASL glucose concentration and bacterial proliferation. Non-diabetic and diabetic rats were intranasally treated with saline, isoproterenol (to increase SGLT1 activity) or phlorizin (to decrease SGLT1 activity); 2 hours later, glucose concentration and bacterial proliferation (methicillin-resistant Sthaphylococcus aureus, MRSA and Pseudomonas aeruginosa, P. aeruginosa) were analyzed in bronchoalveolar lavage (BAL); and alveolar SGLT1 was analyzed by immunohistochemistry. BAL glucose concentration and bacterial proliferation increased in diabetic animals: isoproterenol stimulated SGLT1 migration to luminal membrane, and reduced (50%) the BAL glucose concentration; whereas phlorizin increased the BAL glucose concentration (100%). These regulations were accompanied by parallel changes of in vitro MRSA and P. aeruginosa proliferation in BAL (r = 0.9651 and r = 0.9613, respectively, Pearson correlation). The same regulations were observed in in vivo P. aeruginosa proliferation. In summary, the results indicate a relationship among SGLT1 activity, ASL glucose concentration and pulmonary bacterial proliferation. Besides, the study highlights that, in situations of pulmonary infection risk, such as in diabetic subjects, increased SGLT1 activity may prevent bacterial proliferation whereas decreased SGLT1 activity can exacerbate it.
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25
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Yu H, Yang J, Zhou X, Xiao Q, Lü Y, Xia L. High glucose induces dysfunction of airway epithelial barrier through down-regulation of connexin 43. Exp Cell Res 2016; 342:11-9. [PMID: 26902399 DOI: 10.1016/j.yexcr.2016.02.012] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Revised: 02/16/2016] [Accepted: 02/18/2016] [Indexed: 10/22/2022]
Abstract
The airway epithelium is a barrier to the inhaled antigens and pathogens. Connexin 43 (Cx43) has been found to play critical role in maintaining the function of airway epithelial barrier and be involved in the pathogenesis of the diabetic retinal vasculature, diabetes nephropathy and diabetes skin. Hyperglycemia has been shown to be an independent risk factor for respiratory infections. We hypothesize that the down-regulation of Cx43 induced by HG alters the expression of tight junctions (zonula occludens-1 (ZO-1) and occludin) and contributes to dysfunction of airway epithelial barrier, and Cx43 plays a critical role in the process in human airway epithelial cells (16 HBE). We show that high glucose (HG) decreased the expression of ZO-1 and occludin, disassociated interaction between Cx43 and tight junctions, and then increased airway epithelial transepithelial electrical resistance (TER) and permeability by down-regulation of Cx43 in human airway epithelial cells. These observations demonstrate an important role for Cx43 in regulating HG-induced dysfunction of airway epithelial barrier. These findings may bring new insights into the molecular pathogenesis of pulmonary infection related to diabetes mellitus and lead to novel therapeutic intervention for the dysfunction of airway epithelial barrier in chronic inflammatory airway diseases.
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Affiliation(s)
- Hongmei Yu
- Department of Geriatrics, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China.
| | - Juan Yang
- Division of Respiratory Medicine, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Xiangdong Zhou
- Division of Respiratory Medicine, The Affiliated Hospital of Hainan Medical College, Hainan, China
| | - Qian Xiao
- Department of Geriatrics, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Yang Lü
- Department of Geriatrics, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Li Xia
- Department of Geriatrics, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
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26
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Patkee WRA, Carr G, Baker EH, Baines DL, Garnett JP. Metformin prevents the effects of Pseudomonas aeruginosa on airway epithelial tight junctions and restricts hyperglycaemia-induced bacterial growth. J Cell Mol Med 2016; 20:758-64. [PMID: 26837005 PMCID: PMC4864950 DOI: 10.1111/jcmm.12784] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2015] [Accepted: 12/07/2015] [Indexed: 12/20/2022] Open
Abstract
Lung disease and elevation of blood glucose are associated with increased glucose concentration in the airway surface liquid (ASL). Raised ASL glucose is associated with increased susceptibility to infection by respiratory pathogens including Staphylococcus aureus and Pseudomonas aeruginosa. We have previously shown that the anti‐diabetes drug, metformin, reduces glucose‐induced S. aureus growth across in vitro airway epithelial cultures. The aim of this study was to investigate whether metformin has the potential to reduce glucose‐induced P. aeruginosa infections across airway epithelial (Calu‐3) cultures by limiting glucose permeability. We also explored the effect of P. aeruginosa and metformin on airway epithelial barrier function by investigating changes in tight junction protein abundance. Apical P. aeruginosa growth increased with basolateral glucose concentration, reduced transepithelial electrical resistance (TEER) and increased paracellular glucose flux. Metformin pre‐treatment of the epithelium inhibited the glucose‐induced growth of P. aeruginosa, increased TEER and decreased glucose flux. Similar effects on bacterial growth and TEER were observed with the AMP activated protein kinase agonist, 5‐aminoimidazole‐4‐carboxamide ribonucleotide. Interestingly, metformin was able to prevent the P. aeruginosa‐induced reduction in the abundance of tight junction proteins, claudin‐1 and occludin. Our study highlights the potential of metformin to reduce hyperglycaemia‐induced P. aeruginosa growth through airway epithelial tight junction modulation, and that claudin‐1 and occludin could be important targets to regulate glucose permeability across airway epithelia and supress bacterial growth. Further investigation into the mechanisms regulating metformin and P. aeruginosa action on airway epithelial tight junctions could yield new therapeutic targets to prevent/suppress hyperglycaemia‐induced respiratory infections, avoiding the use of antibiotics.
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Affiliation(s)
| | - Georgina Carr
- Institute of Cellular Medicine, Newcastle University, Newcastle-upon-Tyne, UK
| | - Emma H Baker
- Institute for Infection and Immunity, St George's, University of London, London, UK
| | - Deborah L Baines
- Institute for Infection and Immunity, St George's, University of London, London, UK
| | - James P Garnett
- Institute of Cellular Medicine, Newcastle University, Newcastle-upon-Tyne, UK
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27
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Merigo F, Boschi F, Lasconi C, Benati D, Sbarbati A. Molecules implicated in glucose homeostasis are differentially expressed in the trachea of lean and obese Zucker rats. Eur J Histochem 2016; 60:2557. [PMID: 26972710 PMCID: PMC4800246 DOI: 10.4081/ejh.2016.2557] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2015] [Revised: 11/18/2015] [Accepted: 11/30/2015] [Indexed: 01/16/2023] Open
Abstract
Recent studies indicate that the processes mediated by the (T1R2/T1R3) glucose/sugar receptor of gustatory cells in the tongue, and hormones like leptin and ghrelin contribute to the regulation of glucose homeostasis. Altered plasma levels of leptin and ghrelin are associated with obesity both in humans and rodents. In the present study, we evaluated the ultrastructure of the mucosa, and the expression of molecules implicated in the regulation of glucose homeostasis (GLUT2, SGLT1, T1R3, ghrelin and its receptor) in the trachea of an animal model of obesity (Zucker rats). We found that the tracheal epithelium of obese animals was characterized by the presence of poorly differentiated cells. Ciliated and secretory cells were the cell lineages with greatest loss of differentiation. Severe epithelial alterations were associated with marked deposit of extracellular matrix in the lamina propria. The expression pattern of GLUT2 and SGLT1 glucose transporters was similar in the trachea of both the Zucker rat genotypes, whereas that of T1R3 was reduced in ciliated cells of obese rats. A different immunolocalization for ghrelin was also found in the trachea of obese rats. In conclusion, the tracheal morphological alterations in obese animals seem to compromise the expression of molecules involved in the homeostasis of glucose.
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28
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Douglas JE, Saunders CJ, Reed DR, Cohen NA. A role for airway taste receptor modulation in the treatment of upper respiratory infections. Expert Rev Respir Med 2016; 10:157-70. [PMID: 26731661 DOI: 10.1586/17476348.2016.1135742] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Taste receptors, initially identified in the oral epithelium, have since been shown to be widely distributed, being found in the upper and lower respiratory tracts, gastrointestinal epithelium, thyroid, and brain. The presence of taste receptors in the nasal epithelium has led to the discovery of their role in innate immunity, defending the paranasal sinuses against pathogens. This article addresses the current paradigm for understanding the role of extraoral taste receptors, specifically the T2R38 bitter taste receptor and the T1R2+3 sweet taste receptor, in respiratory innate defenses and presents evidence for the use of these and other taste receptors as therapeutic targets in the management of chronic rhinosinusitis. Future studies should focus on understanding the polymorphisms of taste receptors beyond T2R38 to fully elucidate their potential therapeutic use and lay the groundwork for their modulation in a clinical setting to decrease the health impact and economic burden of upper respiratory disease.
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Affiliation(s)
- Jennifer E Douglas
- a Perelman School of Medicine , University of Pennsylvania , Philadelphia , PA , USA.,b Department of Otorhinolaryngology-Head and Neck Surgery , University of Pennsylvania Health System , Philadelphia , PA , USA.,c Monell Chemical Senses Center , Philadelphia , PA , USA
| | - Cecil J Saunders
- b Department of Otorhinolaryngology-Head and Neck Surgery , University of Pennsylvania Health System , Philadelphia , PA , USA
| | | | - Noam A Cohen
- a Perelman School of Medicine , University of Pennsylvania , Philadelphia , PA , USA.,b Department of Otorhinolaryngology-Head and Neck Surgery , University of Pennsylvania Health System , Philadelphia , PA , USA.,c Monell Chemical Senses Center , Philadelphia , PA , USA.,d Philadelphia Veterans Affairs Medical Center Surgical Services , Philadelphia , PA , USA
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29
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Kinney GL, Baker EH, Klein OL, Black-Shinn JL, Wan ES, Make B, Regan E, Bowler RP, Lutz SM, Young KA, Duca LM, Washko GR, Silverman EK, Crapo JD, Hokanson JE. Pulmonary Predictors of Incident Diabetes in Smokers. CHRONIC OBSTRUCTIVE PULMONARY DISEASES-JOURNAL OF THE COPD FOUNDATION 2016; 3:739-747. [PMID: 27795984 DOI: 10.15326/jcopdf.3.4.2016.0137] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
BACKGROUND Diabetes mellitus and its complications are a large and increasing burden for health care worldwide. Reduced pulmonary function has been observed in diabetes (both type 1 and type 2), and this reduction is thought to occur prior to diagnosis. Other measures of pulmonary health are associated with diabetes, including lower exercise tolerance, greater dyspnea, lower quality of life (as measured by the St. George's Respiratory Questionaire [SGRQ]) and susceptibility to lung infection and these measures may also predate diabetes diagnosis. METHODS We examined 7080 participants in the COPD Genetic Epidemiology (COPDGene) study who did not report diabetes at their baseline visit and who provided health status updates during 4.2 years of longitudinal follow-up (LFU). We used Cox proportional hazards modeling, censoring participants at final LFU contact, reported mortality or report of incident diabetes to model predictors of diabetes. These models were constructed using known risk factors as well as proposed markers related to pulmonary health, forced expiratory volume in 1 second (FEV1), forced vital capacity (FVC), FEV1/FVC, respiratory exacerbations (RE), 6-minute walk distance (6MWD), pulmonary associated quality of life (as measured by the SGRQ), corticosteroid use, chronic bronchitis and dyspnea. RESULTS Over 21,519 person years of follow-up, 392 of 7080 participants reported incident diabetes which was associated with expected predictors; increased body mass index (BMI), high blood pressure, high cholesterol and current smoking status. Age, gender and accumulated smoking exposure were not associated with incident diabetes. Additionally, preserved ratio with impaired spirometry (PRISm) pattern pulmonary function, reduced 6MWD and any report of serious pulmonary events were associated with incident diabetes. CONCLUSIONS This cluster of pulmonary indicators may aid clinicians in identifying and treating patients with pre- or undiagnosed diabetes.
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Affiliation(s)
- Gregory L Kinney
- Department of Epidemiology, Colorado School of Public Health, University of Colorado Anschutz Medical Campus
| | - Emma H Baker
- St. George's, University of London, United Kingdom
| | - Oana L Klein
- Department of Medicine, University of California-San Francisco
| | - Jennifer L Black-Shinn
- Department of Epidemiology, Colorado School of Public Health, University of Colorado Anschutz Medical Campus
| | - Emily S Wan
- Channing Division of Network Medicine, Brigham and Women's Hospital, Boston, Massachusetts
| | - Barry Make
- National Jewish Health and University of Colorado-Denver
| | | | | | - Sharon M Lutz
- Department of Biostatistics, Colorado School of Public Health, University of Colorado Anschutz Medical Campus
| | - Kendra A Young
- Department of Epidemiology, Colorado School of Public Health, University of Colorado Anschutz Medical Campus
| | - Lindsey M Duca
- Department of Epidemiology, Colorado School of Public Health, University of Colorado Anschutz Medical Campus
| | - George R Washko
- Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts
| | - Edwin K Silverman
- Channing Division of Network Medicine, Brigham and Women's Hospital, Boston, Massachusetts
| | - James D Crapo
- National Jewish Health and University of Colorado-Denver
| | - John E Hokanson
- Department of Epidemiology, Colorado School of Public Health, University of Colorado Anschutz Medical Campus
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30
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Lee RJ, Cohen NA. Sinonasal solitary chemosensory cells "taste" the upper respiratory environment to regulate innate immunity. Am J Rhinol Allergy 2015; 28:366-73. [PMID: 25198020 DOI: 10.2500/ajra.2014.28.4077] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND It is not fully understood how sinonasal epithelial cells detect the presence of pathogens and activate innate defense responses necessary for protecting the upper airway from infection. One mechanism is through bitter taste receptors (T2Rs), which are expressed in the sinonasal cavity. One T2R isoform, T2R38, is expressed in ciliated cells and detects quorum-sensing molecules from gram-negative bacteria, activating antimicrobial nitric oxide production. More recent studies have examined the role of T2Rs expressed in a sinonasal cell type that has only recently been identified in humans, the solitary chemosensory cell (SCC). We sought to provide an overview of SCCs and taste receptor function in human sinonasal defense as well as implications for chronic rhinosinusitis (CRS). METHODS A literature review of the current knowledge of SCCs and taste receptors in sinonasal physiology and CRS was conducted. RESULTS Human sinonasal SCCs express both bitter T2R and sweet T1R2/3 receptors. Activation of SCC T2Rs activates a calcium signal that propagates to the surrounding epithelial cells and causes secretion of antimicrobial peptides. T1R2/3 sweet receptor activation by physiological airway surface liquid (ASL) glucose concentrations attenuates the T2R response, likely as a mechanism to prevent full activation of the T2R pathway except during times of infection, when pathogens may consume ASL glucose and reduce its concentration. CONCLUSION SCCs appear to be important mediators of upper airway innate immunity, as the SCC T2Rs regulate antimicrobial peptide secretion, but further study is needed to determine the specific T2R isoforms involved as well as whether polymorphisms in these isoforms affect susceptibility to infection or patient outcomes in CRS. The inhibitory role of T1R2/3 sweet receptor suggests that T1R2/3 blockers may have therapeutic potential in some CRS patients, particularly those with diabetes mellitus. However, further clinical study of the relationship between infection and T1R2/3 genotype is required.
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Affiliation(s)
- Robert J Lee
- Department of Otorhinolaryngology-Head and Neck Surgery, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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31
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Hatten KM, Palmer JN, Lee RJ, Adappa ND, Kennedy DW, Cohen NA. Corticosteroid use does not alter nasal mucus glucose in chronic rhinosinusitis. Otolaryngol Head Neck Surg 2015; 152:1140-4. [PMID: 25820586 DOI: 10.1177/0194599815577567] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2014] [Accepted: 02/24/2015] [Indexed: 01/09/2023]
Abstract
OBJECTIVES To evaluate nasal mucus glucose concentrations in patients with and without chronic rhinosinusitis and determine if corticosteroid therapy alters mucus glucose. STUDY DESIGN Prospective observational study. SETTING Single tertiary care center. SUBJECTS Ninety-five patients presenting to an otolaryngology clinic. METHODS Participants completed questionnaires that included a history of medical and surgical therapies as well as sinusitis-specific quality-of-life measurements. Nasal mucus was collected in an outpatient clinic using an open cell foam technique. The nasal mucus glucose concentrations of patients with and without chronic rhinosinusitis were compared to the use of systemic and topical glucocorticoid treatment. RESULTS A statistically significant difference was measured between mean nasal glucose secretions of control patients, 10.2 mg/dL, compared with patients diagnosed with chronic rhinosinusitis, 18.4 mg/dL (P < .0001). Use of corticosteroids, both topical and systemic, did not correlate with nasal glucose concentrations. CONCLUSION Patients diagnosed with chronic rhinosinusitis have elevated nasal glucose concentrations compared with control patients, and this elevated nasal glucose level was independent of corticosteroid use. Nasal glucose may independently contribute to the pathophysiology of chronic rhinosinusitis.
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Affiliation(s)
- Kyle M Hatten
- Department of Otorhinolaryngology-Head & Neck Surgery, University of Pennsylvania Health System, Philadelphia, Pennsylvania, USA
| | - James N Palmer
- Department of Otorhinolaryngology-Head & Neck Surgery, University of Pennsylvania Health System, Philadelphia, Pennsylvania, USA
| | - Robert J Lee
- Department of Otorhinolaryngology-Head & Neck Surgery, University of Pennsylvania Health System, Philadelphia, Pennsylvania, USA
| | - Nithin D Adappa
- Department of Otorhinolaryngology-Head & Neck Surgery, University of Pennsylvania Health System, Philadelphia, Pennsylvania, USA
| | - David W Kennedy
- Department of Otorhinolaryngology-Head & Neck Surgery, University of Pennsylvania Health System, Philadelphia, Pennsylvania, USA
| | - Noam A Cohen
- Department of Otorhinolaryngology-Head & Neck Surgery, University of Pennsylvania Health System, Philadelphia, Pennsylvania, USA Philadelphia Veterans Affairs Medical Center Surgical Services, Philadelphia, Pennsylvania, USA
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Yu H, Yang J, Xiao Q, Lü Y, Zhou X, Xia L, Nie D. Regulation of high glucose-mediated mucin expression by matrix metalloproteinase-9 in human airway epithelial cells. Exp Cell Res 2015; 333:127-35. [PMID: 25704757 DOI: 10.1016/j.yexcr.2015.02.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2014] [Revised: 02/02/2015] [Accepted: 02/10/2015] [Indexed: 11/15/2022]
Abstract
Mucus hypersecretion is the key manifestation in patients with chronic inflammatory airway diseases and mucin 5AC (MUC5AC) is a major component of airway mucus. Matrix metalloproteinases (MMP)-9, have been found to be involved in the pathogenesis of inflammatory airway diseases. Hyperglycemia has been shown to be an independent risk factor for respiratory infections. We hypothesize that high glucose (HG)-regulates MMP-9 production and MMP-9 activity through nicotinamide adenine dinucleotide phosphate (NADPH)/reactive oxygen species (ROS) cascades pathways, leading to mucin production in human airway epithelial cells (16HBE). We show that HG increases MMP-9 production, MMP-9 activity and MUC5AC expression. These effects are prevented by small interfering RNA (siRNA) for MMP-9, indicating that HG-induced mucin production is MMP-9-dependent. HG activates MMP-9 production, MMP-9 activity and MUC5AC overproduction, which is inhibited by nPG, DMSO and DPI (inhibitors of ROS and NADPH), suggesting that HG-activated mucin synthesis is mediated by NADPH/ROS in 16HBE cells. These observations demonstrate an important role for MMP-9 activated by NADPH/ROS signaling pathways in regulating HG-induced MUC5AC expression. These findings may bring new insights into the molecular pathogenesis of the infections related to diabetes mellitus and lead to novel therapeutic intervention for mucin overproduction in chronic inflammatory airway diseases.
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Affiliation(s)
- Hongmei Yu
- Department of Geriatrics, The First Affiliated Hospital of Chongqing Medical University, No. 1, Youyi Road, Yuzhong District, Chongqing 400016, China.
| | - Juan Yang
- Division of Respiratory Medicine, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Qian Xiao
- Department of Geriatrics, The First Affiliated Hospital of Chongqing Medical University, No. 1, Youyi Road, Yuzhong District, Chongqing 400016, China
| | - Yang Lü
- Department of Geriatrics, The First Affiliated Hospital of Chongqing Medical University, No. 1, Youyi Road, Yuzhong District, Chongqing 400016, China
| | - Xiangdong Zhou
- Division of Respiratory Medicine, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Li Xia
- Department of Geriatrics, The First Affiliated Hospital of Chongqing Medical University, No. 1, Youyi Road, Yuzhong District, Chongqing 400016, China
| | - Daijing Nie
- Department of Geriatrics, The First Affiliated Hospital of Chongqing Medical University, No. 1, Youyi Road, Yuzhong District, Chongqing 400016, China
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Lee RJ, Cohen NA. Taste receptors in innate immunity. Cell Mol Life Sci 2015; 72:217-36. [PMID: 25323130 PMCID: PMC4286424 DOI: 10.1007/s00018-014-1736-7] [Citation(s) in RCA: 91] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2014] [Revised: 09/11/2014] [Accepted: 09/16/2014] [Indexed: 02/07/2023]
Abstract
Taste receptors were first identified on the tongue, where they initiate a signaling pathway that communicates information to the brain about the nutrient content or potential toxicity of ingested foods. However, recent research has shown that taste receptors are also expressed in a myriad of other tissues, from the airway and gastrointestinal epithelia to the pancreas and brain. The functions of many of these extraoral taste receptors remain unknown, but emerging evidence suggests that bitter and sweet taste receptors in the airway are important sentinels of innate immunity. This review discusses taste receptor signaling, focusing on the G-protein-coupled receptors that detect bitter, sweet, and savory tastes, followed by an overview of extraoral taste receptors and in-depth discussion of studies demonstrating the roles of taste receptors in airway innate immunity. Future research on extraoral taste receptors has significant potential for identification of novel immune mechanisms and insights into host-pathogen interactions.
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Affiliation(s)
- Robert J. Lee
- Department of Otorhinolaryngology, Perelman School of Medicine, University of Pennsylvania, Ravdin Building, 5th floor, Philadelphia, PA 19104 USA
| | - Noam A. Cohen
- Department of Otorhinolaryngology, Perelman School of Medicine, University of Pennsylvania, Ravdin Building, 5th floor, Philadelphia, PA 19104 USA
- Philadelphia Veterans Affairs Medical Center Surgical Services, 3900 Woodland Ave, Philadelphia, PA 19104 USA
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34
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Helassa N, Garnett JP, Farrant M, Khan F, Pickup JC, Hahn KM, MacNevin CJ, Tarran R, Baines DL. A novel fluorescent sensor protein for detecting changes in airway surface liquid glucose concentration. Biochem J 2014; 464:213-20. [PMID: 25220254 PMCID: PMC4357280 DOI: 10.1042/bj20141041] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Both lung disease and elevation of blood glucose are associated with increased glucose concentration (from 0.4 to ~4.0 mM) in the airway surface liquid (ASL). This perturbation of ASL glucose makes the airway more susceptible to infection by respiratory pathogens. ASL is minute (~1 μl/cm(2)) and the measurement of glucose concentration in the small volume ASL is extremely difficult. Therefore, we sought to develop a fluorescent biosensor with sufficient sensitivity to determine glucose concentrations in ASL in situ. We coupled a range of environmentally sensitive fluorophores to mutated forms of a glucose/galactose-binding protein (GBP) including H152C and H152C/A213R and determined their equilibrium binding properties. Of these, GBP H152C/A213R-BADAN (Kd 0.86 ± 0.01 mM, Fmax/F0 3.6) was optimal for glucose sensing and in ASL increased fluorescence when basolateral glucose concentration was raised from 1 to 20 mM. Moreover, interpolation of the data showed that the glucose concentration in ASL was increased, with results similar to that using glucose oxidase analysis. The fluorescence of GBP H152C/A213R-BADAN in native ASL from human airway epithelial cultures in situ was significantly increased over time when basolateral glucose was increased from 5 to 20 mM. Overall our data indicate that this GBP is a useful tool to monitor glucose homoeostasis in the lung.
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Affiliation(s)
- Nordine Helassa
- Institute of Cardiovascular and Cell Science, St George’s, University of London, London SW17 0RE, U.K
| | - James P. Garnett
- Institute for Infection and Immunity, St George’s, University of London, London SW17 0RE, U.K
| | - Matthew Farrant
- Institute for Infection and Immunity, St George’s, University of London, London SW17 0RE, U.K
| | - Faaizah Khan
- Diabetes Research Group, King’s College London, Guy’s Hospital Campus, London SE1 1UL, U.K
| | - John C. Pickup
- Diabetes Research Group, King’s College London, Guy’s Hospital Campus, London SE1 1UL, U.K
| | - Klaus M. Hahn
- Department of Pharmacology/Cell Biology & Physiology, University of North Carolina, Chapel Hill, NC, 27599 U.S.A
| | - Christopher J. MacNevin
- Department of Pharmacology/Cell Biology & Physiology, University of North Carolina, Chapel Hill, NC, 27599 U.S.A
| | - Robert Tarran
- Department of Pharmacology/Cell Biology & Physiology, University of North Carolina, Chapel Hill, NC, 27599 U.S.A
| | - Deborah L. Baines
- Institute for Infection and Immunity, St George’s, University of London, London SW17 0RE, U.K
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Garnett JP, Braun D, McCarthy AJ, Farrant MR, Baker EH, Lindsay JA, Baines DL. Fructose transport-deficient Staphylococcus aureus reveals important role of epithelial glucose transporters in limiting sugar-driven bacterial growth in airway surface liquid. Cell Mol Life Sci 2014; 71:4665-73. [PMID: 24810961 PMCID: PMC4232747 DOI: 10.1007/s00018-014-1635-y] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2014] [Revised: 04/11/2014] [Accepted: 04/28/2014] [Indexed: 02/05/2023]
Abstract
Hyperglycaemia as a result of diabetes mellitus or acute illness is associated with increased susceptibility to respiratory infection with Staphylococcus aureus. Hyperglycaemia increases the concentration of glucose in airway surface liquid (ASL) and promotes the growth of S. aureus in vitro and in vivo. Whether elevation of other sugars in the blood, such as fructose, also results in increased concentrations in ASL is unknown and whether sugars in ASL are directly utilised by S. aureus for growth has not been investigated. We obtained mutant S. aureus JE2 strains with transposon disrupted sugar transport genes. NE768(fruA) exhibited restricted growth in 10 mM fructose. In H441 airway epithelial-bacterial co-culture, elevation of basolateral sugar concentration (5-20 mM) increased the apical growth of JE2. However, sugar-induced growth of NE768(fruA) was significantly less when basolateral fructose rather than glucose was elevated. This is the first experimental evidence to show that S. aureus directly utilises sugars present in the ASL for growth. Interestingly, JE2 growth was promoted less by glucose than fructose. Net transepithelial flux of D-glucose was lower than D-fructose. However, uptake of D-glucose was higher than D-fructose across both apical and basolateral membranes consistent with the presence of GLUT1/10 in the airway epithelium. Therefore, we propose that the preferential uptake of glucose (compared to fructose) limits its accumulation in ASL. Pre-treatment with metformin increased transepithelial resistance and reduced the sugar-dependent growth of S. aureus. Thus, epithelial paracellular permeability and glucose transport mechanisms are vital to maintain low glucose concentration in ASL and limit bacterial nutrient sources as a defence against infection.
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Affiliation(s)
- James P. Garnett
- Institute for Infection and Immunity, St George’s, University of London, Tooting, London, SW17 0RE UK
| | - Daniela Braun
- Institute for Infection and Immunity, St George’s, University of London, Tooting, London, SW17 0RE UK
| | - Alex J. McCarthy
- Institute for Infection and Immunity, St George’s, University of London, Tooting, London, SW17 0RE UK
| | - Matthew R. Farrant
- Institute for Infection and Immunity, St George’s, University of London, Tooting, London, SW17 0RE UK
| | - Emma H. Baker
- Institute for Infection and Immunity, St George’s, University of London, Tooting, London, SW17 0RE UK
| | - Jodi A. Lindsay
- Institute for Infection and Immunity, St George’s, University of London, Tooting, London, SW17 0RE UK
| | - Deborah L. Baines
- Institute for Infection and Immunity, St George’s, University of London, Tooting, London, SW17 0RE UK
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Haghi M, Ong HX, Traini D, Young P. Across the pulmonary epithelial barrier: Integration of physicochemical properties and human cell models to study pulmonary drug formulations. Pharmacol Ther 2014; 144:235-52. [DOI: 10.1016/j.pharmthera.2014.05.003] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2014] [Accepted: 04/30/2014] [Indexed: 11/16/2022]
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Bitter and sweet taste receptors in the respiratory epithelium in health and disease. J Mol Med (Berl) 2014; 92:1235-44. [PMID: 25391251 DOI: 10.1007/s00109-014-1222-6] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2014] [Revised: 11/01/2014] [Accepted: 11/04/2014] [Indexed: 11/27/2022]
Abstract
Taste receptors on the tongue communicate information to the brain about the nutrient content or potential toxicity of ingested foods. However, recent research has now shown that taste receptors are also expressed far beyond the tongue, from the airway and gastrointestinal epithelia to the pancreas and brain. The functions of many of these so-called extraoral taste receptors remain unknown, but emerging basic science and clinical evidence suggests that bitter and sweet taste receptors in the airway are important in sensing bacteria and regulating innate immunity. This review focuses on the role of bitter and sweet taste receptors in human airway innate immunity and the potential clinical relevance to airway infections. The T2R38 bitter taste receptor in sinonasal cilia detects bitter bacterial quorum-sensing molecules and activates nitric oxide-dependent innate immune responses. Polymorphisms that underlie T2R38 functionality also appear to be involved in susceptibility to upper respiratory infection and chronic rhinosinusitis (CRS). Bitter and sweet receptors in specialized sinonasal solitary chemosensory cells control antimicrobial peptide secretion, which may have important implications for airway infections in CRS patients as well as patients with diabetes mellitus. Future research on taste receptors in the airway has tremendous potential to identify immune mechanisms involved in host-pathogen interactions and thus reveal novel therapeutic targets.
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Lee RJ, Kofonow JM, Rosen PL, Siebert AP, Chen B, Doghramji L, Xiong G, Adappa ND, Palmer JN, Kennedy DW, Kreindler JL, Margolskee RF, Cohen NA. Bitter and sweet taste receptors regulate human upper respiratory innate immunity. J Clin Invest 2014; 124:1393-405. [PMID: 24531552 DOI: 10.1172/jci72094] [Citation(s) in RCA: 287] [Impact Index Per Article: 28.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2013] [Accepted: 12/11/2013] [Indexed: 12/11/2022] Open
Abstract
Bitter taste receptors (T2Rs) in the human airway detect harmful compounds, including secreted bacterial products. Here, using human primary sinonasal air-liquid interface cultures and tissue explants, we determined that activation of a subset of airway T2Rs expressed in nasal solitary chemosensory cells activates a calcium wave that propagates through gap junctions to the surrounding respiratory epithelial cells. The T2R-dependent calcium wave stimulated robust secretion of antimicrobial peptides into the mucus that was capable of killing a variety of respiratory pathogens. Furthermore, sweet taste receptor (T1R2/3) activation suppressed T2R-mediated antimicrobial peptide secretion, suggesting that T1R2/3-mediated inhibition of T2Rs prevents full antimicrobial peptide release during times of relative health. In contrast, during acute bacterial infection, T1R2/3 is likely deactivated in response to bacterial consumption of airway surface liquid glucose, alleviating T2R inhibition and resulting in antimicrobial peptide secretion. We found that patients with chronic rhinosinusitis have elevated glucose concentrations in their nasal secretions, and other reports have shown that patients with hyperglycemia likewise have elevated nasal glucose levels. These data suggest that increased glucose in respiratory secretions in pathologic states, such as chronic rhinosinusitis or hyperglycemia, promotes tonic activation of T1R2/3 and suppresses T2R-mediated innate defense. Furthermore, targeting T1R2/3-dependent suppression of T2Rs may have therapeutic potential for upper respiratory tract infections.
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Kinney GL, Black-Shinn JL, Wan ES, Make B, Regan E, Lutz S, Soler X, Silverman EK, Crapo J, Hokanson JE. Pulmonary function reduction in diabetes with and without chronic obstructive pulmonary disease. Diabetes Care 2014; 37:389-95. [PMID: 24026562 PMCID: PMC3898761 DOI: 10.2337/dc13-1435] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
OBJECTIVE Diabetes damages major organ systems through disrupted glycemic control and increased inflammation. The effects of diabetes on the lung have been of interest for decades, but the modest reduction in pulmonary function and its nonprogressive nature have limited its investigation. A recent systematic review found that diabetes was associated with reductions in forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC), and diffusing capacity for carbon monoxide of the lung and increased FEV1/FVC. They reported pooled results including few smokers. This study will examine measures of pulmonary function in participants with extensive smoking exposure. RESEARCH DESIGN AND METHODS We examined pulmonary function in participants with a >10-pack-year history of smoking with and without diabetes with and without chronic obstructive pulmonary disease (COPD). We measured pulmonary function, exercise capacity, and pulmonary-related quality of life in 10,129 participants in the Genetic Epidemiology of Chronic Obstructive Pulmonary Disease (COPDGene) Study. RESULTS Participants with diabetes were observed to have reduced pulmonary function after controlling for known risk factors and also significant reductions in exercise capacity and quality of life across functional stages of COPD. CONCLUSIONS Pulmonary function in patients with ≥10 pack-years of smoking and diabetes is reduced, and this decrease is associated with significant reductions in activity-related quality of life and exercise capacity.
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Garnett JP, Gray MA, Tarran R, Brodlie M, Ward C, Baker EH, Baines DL. Elevated paracellular glucose flux across cystic fibrosis airway epithelial monolayers is an important factor for Pseudomonas aeruginosa growth. PLoS One 2013; 8:e76283. [PMID: 24124542 PMCID: PMC3790714 DOI: 10.1371/journal.pone.0076283] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2013] [Accepted: 08/22/2013] [Indexed: 01/17/2023] Open
Abstract
People with cystic fibrosis (CF) who develop related diabetes (CFRD) have accelerated pulmonary decline, increased infection with antibiotic-resistant Pseudomonas aeruginosa and increased pulmonary exacerbations. We have previously shown that glucose concentrations are elevated in airway surface liquid (ASL) of people with CF, particularly in those with CFRD. We therefore explored the hypotheses that glucose homeostasis is altered in CF airway epithelia and that elevation of glucose flux into ASL drives increased bacterial growth, with an effect over and above other cystic fibrosis transmembrane conductance regulator (CFTR)-related ASL abnormalities. The aim of this study was to compare the mechanisms governing airway glucose homeostasis in CF and non-CF primary human bronchial epithelial (HBE) monolayers, under normal conditions and in the presence of Ps. aeruginosa filtrate. HBE-bacterial co-cultures were performed in the presence of 5 mM or 15 mM basolateral glucose to investigate how changes in blood glucose, such as those seen in CFRD, affects luminal Ps. aeruginosa growth. Calu-3 cell monolayers were used to evaluate the potential importance of glucose on Ps. aeruginosa growth, in comparison to other hallmarks of the CF ASL, namely mucus hyperviscosity and impaired CFTR-dependent fluid secretions. We show that elevation of basolateral glucose promotes the apical growth of Ps. aeruginosa on CF airway epithelial monolayers more than non-CF monolayers. Ps. aeruginosa secretions elicited more glucose flux across CF airway epithelial monolayers compared to non-CF monolayers which we propose increases glucose availability in ASL for bacterial growth. In addition, elevating basolateral glucose increased Ps. aeruginosa growth over and above any CFTR-dependent effects and the presence or absence of mucus in Calu-3 airway epithelia-bacteria co-cultures. Together these studies highlight the importance of glucose as an additional factor in promoting Ps. aeruginosa growth and respiratory infection in CF disease.
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Affiliation(s)
- James P. Garnett
- Division of Biomedical Sciences, St George's University of London, London, United Kingdom
| | - Michael A. Gray
- Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle-upon-Tyne, United Kingdom
| | - Robert Tarran
- Cystic Fibrosis/Pulmonary Research and Treatment Centre, University of North Carolina, Chapel Hill, North Carolina, United States of America
| | - Malcolm Brodlie
- Institute of Cellular Medicine, Newcastle University, Newcastle-upon-Tyne, United Kingdom
| | - Christopher Ward
- Institute of Cellular Medicine, Newcastle University, Newcastle-upon-Tyne, United Kingdom
| | - Emma H. Baker
- Division of Biomedical Sciences, St George's University of London, London, United Kingdom
| | - Deborah L. Baines
- Division of Biomedical Sciences, St George's University of London, London, United Kingdom
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Kraft R, Herndon DN, Mlcak RP, Finnerty CC, Cox RA, Williams FN, Jeschke MG. Bacterial respiratory tract infections are promoted by systemic hyperglycemia after severe burn injury in pediatric patients. Burns 2013; 40:428-35. [PMID: 24074819 DOI: 10.1016/j.burns.2013.07.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2013] [Revised: 07/10/2013] [Accepted: 07/11/2013] [Indexed: 12/11/2022]
Abstract
BACKGROUND Burns are associated with hyperglycemia leading to increased incidence of infections with pneumonia being one of the most prominent and adverse complications. Recently, various studies in critically ill patients indicated that increased pulmonary glucose levels with airway/blood glucose threshold over 150 mg/dl lead to an overwhelming growth of bacteria in the broncho-pulmonary system, subsequently resulting in an increased risk of pulmonary infections. The aim of the present study was to determine whether a similar cutoff value exists for severely burned pediatric patients. METHODS One-hundred six severely burned pediatric patients were enrolled in the study. Patients were divided in two groups: high (H) defined as daily average glucose levels >75% of LOS >150 mg/dl), and low (L) with daily average glucose levels >75% of the LOS <150 mg/dl). Incidences of pneumonia, atelectasis, and acute respiratory distress syndrome (ARDS) were assessed. Incidence of infections, sepsis, and respiratory parameters were recorded. Blood was analyzed for glucose and insulin levels. Statistical analysis was performed using Student's t-test and chi-square test. Significance was set at p<0.05. RESULTS Patient groups were similar in demographics and injury characteristics. Pneumonia in patients on the mechanical ventilation (L: 21%, H: 32%) and off mechanical ventilation (L: 5%, H: 15%), as well as ARDS were significantly higher in the high group (L: 3%, H: 19%), p<0.05, while atelectasis was not different. Patients in the high group required significantly longer ventilation compared to low patients (p<0.05). Furthermore, incidence of infection and sepsis were significantly higher in the high group, p<0.05. CONCLUSION Our results indicate that systemic glucose levels over 150 mg/dl are associated with a higher incidence of pneumonia confirming the previous studies in critically ill patients.
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Affiliation(s)
- Robert Kraft
- Department of Trauma, Klinikum Memmingen, Germany
| | - David N Herndon
- Shriners Hospitals for Children, Galveston, TX, United States; Department of Surgery, United States
| | - Ronald P Mlcak
- Shriners Hospitals for Children, Galveston, TX, United States
| | - Celeste C Finnerty
- Shriners Hospitals for Children, Galveston, TX, United States; Department of Surgery, United States; Sealy Center for Molecular Medicine, and the Institute for Translational Science, University Texas Medical Branch, Galveston, TX, United States
| | - Robert A Cox
- Shriners Hospitals for Children, Galveston, TX, United States
| | | | - Marc G Jeschke
- Department of Surgery, Division of Plastic Surgery, Department of Immunology, Ross Tilley Burn Centre - Sunnybrook Health Sciences Centre, Sunnybrook Research Institute, Toronto, ON, Canada.
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Garnett JP, Baker EH, Naik S, Lindsay JA, Knight GM, Gill S, Tregoning JS, Baines DL. Metformin reduces airway glucose permeability and hyperglycaemia-induced Staphylococcus aureus load independently of effects on blood glucose. Thorax 2013; 68:835-45. [PMID: 23709760 PMCID: PMC3756442 DOI: 10.1136/thoraxjnl-2012-203178] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
BACKGROUND Diabetes is a risk factor for respiratory infection, and hyperglycaemia is associated with increased glucose in airway surface liquid and risk of Staphylococcus aureus infection. OBJECTIVES To investigate whether elevation of basolateral/blood glucose concentration promotes airway Staphylococcus aureus growth and whether pretreatment with the antidiabetic drug metformin affects this relationship. METHODS Human airway epithelial cells grown at air-liquid interface (±18 h pre-treatment, 30 μM-1 mM metformin) were inoculated with 5×10(5) colony-forming units (CFU)/cm(2) S aureus 8325-4 or JE2 or Pseudomonas aeruginosa PA01 on the apical surface and incubated for 7 h. Wild-type C57BL/6 or db/db (leptin receptor-deficient) mice, 6-10 weeks old, were treated with intraperitoneal phosphate-buffered saline or 40 mg/kg metformin for 2 days before intranasal inoculation with 1×10(7) CFU S aureus. Mice were culled 24 h after infection and bronchoalveolar lavage fluid collected. RESULTS Apical S aureus growth increased with basolateral glucose concentration in an in vitro airway epithelia-bacteria co-culture model. S aureus reduced transepithelial electrical resistance (RT) and increased paracellular glucose flux. Metformin inhibited the glucose-induced growth of S aureus, increased RT and decreased glucose flux. Diabetic (db/db) mice infected with S aureus exhibited a higher bacterial load in their airways than control mice after 2 days and metformin treatment reversed this effect. Metformin did not decrease blood glucose but reduced paracellular flux across ex vivo murine tracheas. CONCLUSIONS Hyperglycaemia promotes respiratory S aureus infection, and metformin modifies glucose flux across the airway epithelium to limit hyperglycaemia-induced bacterial growth. Metformin might, therefore, be of additional benefit in the prevention and treatment of respiratory infection.
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Affiliation(s)
- James P Garnett
- Division of Biomedical Sciences, Centre for Cell Physiology and Pharmacology, St George's, University of London, London, UK
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Abstract
Lung epithelial cells interconnected by tight junctions provide a barrier to the free diffusion of solutes into airspaces. Transmembrane tight junction proteins known as claudins are essential for epithelial barrier function. Claudins are regulated through interactions with each other that are coordinated with other transmembrane tight junction proteins and cytosolic scaffold proteins. Of the 14 claudins expressed by the alveolar epithelium, claudin-3, claudin-4, and claudin-18 are the most prominent; each confers unique properties to alveolar barrier function. In particular, a protective role for claudin-4 in preventing lung injury has emerged. By contrast, lung diseases that affect claudin expression and impair barrier function, including alcoholic lung syndrome and sepsis, prime the lung for pulmonary edema. Thus, approaches to restore and/or augment lung claudin expression provide potential targets for promoting healthy barrier function.
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Affiliation(s)
- Michael Koval
- Division of Pulmonary, Allergy and Critical Care Medicine, Department of Medicine, Emory University, Atlanta, Georgia 30322, USA.
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Merigo F, Benati D, Cristofoletti M, Amarù F, Osculati F, Sbarbati A. Glucose transporter/T1R3-expressing cells in rat tracheal epithelium. J Anat 2012; 221:138-50. [PMID: 22640462 DOI: 10.1111/j.1469-7580.2012.01522.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Glucose transport plays an important role in maintaining low sugar concentration in airway surface liquid (ASL), which is critical for mucociliary clearance and bacterial colonization. Experimental evidence indicates that glucose/hexose uptake in lung/airway cells occurs by means of two structurally distinct glucose transporter pathways: the Na(+) -dependent glucose transporters (SGLT family) and the facilitative glucose transporters (GLUT family). In this study, we examined the expression of the major glucose transporters of the intestine, GLUT2, GLUT5, SGLT1 and T1R3 taste receptor subunit, in the trachea of rats using immunohistochemistry and immunoelectron microscopy, and compared them using double-labeled confocal microscopy. We found that GLUT2, GLUT5, SGLT1 and T1R3 are selectively expressed in different cell types. T1R3 and GLUT2 are predominantly expressed in subsets of solitary chemoreceptor cells (SCCs) and ciliated cells, GLUT5 is present in subsets of SCCs and in secretory cells, and SGLT1 is exclusively expressed in a unique cell type, SCCs. Furthermore, we demonstrated that T1R3 is colocalized with SGLT1 in SCCs and with GLUT2 transporter in ciliated cells. In conclusion, these findings reveal that different cell types are associated with the uptake of glucose in ASL and that, due to their T1R3 expression, SCCs and ciliated cells are most likely to participate in the chemosensory process in ASL.
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Affiliation(s)
- Flavia Merigo
- Department of Neurological, Neuropsychological, Morphological and Movement Sciences, Human Anatomy and Histology Section, University of Verona, School of Medicine, Verona, Italy.
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Garnett JP, Nguyen TT, Moffatt JD, Pelham ER, Kalsi KK, Baker EH, Baines DL. Proinflammatory mediators disrupt glucose homeostasis in airway surface liquid. THE JOURNAL OF IMMUNOLOGY 2012; 189:373-80. [PMID: 22623330 DOI: 10.4049/jimmunol.1200718] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The glucose concentration of the airway surface liquid (ASL) is much lower than that in blood and is tightly regulated by the airway epithelium. ASL glucose is elevated in patients with viral colds, cystic fibrosis, chronic obstructive pulmonary disease, and asthma. Elevated ASL glucose is also associated with increased incidence of respiratory infection. However, the mechanism by which ASL glucose increases under inflammatory conditions is unknown. The aim of this study was to investigate the effect of proinflammatory mediators (PIMs) on the mechanisms governing airway glucose homeostasis in polarized monolayers of human airway (H441) and primary human bronchial epithelial (HBE) cells. Monolayers were treated with TNF-α, IFN-γ, and LPS during 72 h. PIM treatment led to increase in ASL glucose concentration and significantly reduced H441 and HBE transepithelial resistance. This decline in transepithelial resistance was associated with an increase in paracellular permeability of glucose. Similar enhanced rates of paracellular glucose flux were also observed across excised trachea from LPS-treated mice. Interestingly, PIMs enhanced glucose uptake across the apical, but not the basolateral, membrane of H441 and HBE monolayers. This increase was predominantly via phloretin-sensitive glucose transporter (GLUT)-mediated uptake, which coincided with an increase in GLUT-2 and GLUT-10 abundance. In conclusion, exposure of airway epithelial monolayers to PIMs results in increased paracellular glucose flux, as well as apical GLUT-mediated glucose uptake. However, uptake was insufficient to limit glucose accumulation in ASL. To our knowledge, these data provide for the first time a mechanism to support clinical findings that ASL glucose concentration is increased in patients with airway inflammation.
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Affiliation(s)
- James P Garnett
- Division of Biomedical Sciences, St. George's, University of London, Tooting, London SW17 0RE, United Kingdom
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Valenza F, Rosso L, Coppola S, Froio S, Colombo J, Dossi R, Fumagalli J, Salice V, Pizzocri M, Conte G, Gatti S, Santambrogio L, Gattinoni L. β-Adrenergic agonist infusion during extracorporeal lung perfusion: Effects on glucose concentration in the perfusion fluid and on lung function. J Heart Lung Transplant 2012; 31:524-30. [DOI: 10.1016/j.healun.2012.02.001] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2011] [Revised: 12/16/2011] [Accepted: 02/02/2012] [Indexed: 11/25/2022] Open
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Pezzulo AA, Gutiérrez J, Duschner KS, McConnell KS, Taft PJ, Ernst SE, Yahr TL, Rahmouni K, Klesney-Tait J, Stoltz DA, Zabner J. Glucose depletion in the airway surface liquid is essential for sterility of the airways. PLoS One 2011; 6:e16166. [PMID: 21311590 PMCID: PMC3029092 DOI: 10.1371/journal.pone.0016166] [Citation(s) in RCA: 86] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2010] [Accepted: 12/08/2010] [Indexed: 11/19/2022] Open
Abstract
Diabetes mellitus predisposes the host to bacterial infections. Moreover, hyperglycemia has been shown to be an independent risk factor for respiratory infections. The luminal surface of airway epithelia is covered by a thin layer of airway surface liquid (ASL) and is normally sterile despite constant exposure to bacteria. The balance between bacterial growth and killing in the airway determines the outcome of exposure to inhaled or aspirated bacteria: infection or sterility. We hypothesized that restriction of carbon sources--including glucose--in the ASL is required for sterility of the lungs. We found that airway epithelia deplete glucose from the ASL via a novel mechanism involving polarized expression of GLUT-1 and GLUT-10, intracellular glucose phosphorylation, and low relative paracellular glucose permeability in well-differentiated cultures of human airway epithelia and in segments of airway epithelia excised from human tracheas. Moreover, we found that increased glucose concentration in the ASL augments growth of P. aeruginosa in vitro and in the lungs of hyperglycemic ob/ob and db/db mice in vivo. In contrast, hyperglycemia had no effect on intrapulmonary bacterial growth of a P. aeruginosa mutant that is unable to utilize glucose as a carbon source. Our data suggest that depletion of glucose in the airway epithelial surface is a novel mechanism for innate immunity. This mechanism is important for sterility of the airways and has implications in hyperglycemia and conditions that result in disruption of the epithelial barrier in the lung.
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Affiliation(s)
- Alejandro A. Pezzulo
- Department of Internal Medicine, University of Iowa, Iowa City, Iowa, United States of America
| | - Jeydith Gutiérrez
- Department of Internal Medicine, University of Iowa, Iowa City, Iowa, United States of America
| | - Kelly S. Duschner
- Department of Internal Medicine, University of Iowa, Iowa City, Iowa, United States of America
| | - Kelly S. McConnell
- Department of Internal Medicine, University of Iowa, Iowa City, Iowa, United States of America
| | - Peter J. Taft
- Department of Internal Medicine, University of Iowa, Iowa City, Iowa, United States of America
| | - Sarah E. Ernst
- Department of Internal Medicine, University of Iowa, Iowa City, Iowa, United States of America
| | - Timothy L. Yahr
- Department of Microbiology, University of Iowa, Iowa City, Iowa, United States of America
| | - Kamal Rahmouni
- Department of Internal Medicine, University of Iowa, Iowa City, Iowa, United States of America
| | - Julia Klesney-Tait
- Department of Internal Medicine, University of Iowa, Iowa City, Iowa, United States of America
| | - David A. Stoltz
- Department of Internal Medicine, University of Iowa, Iowa City, Iowa, United States of America
| | - Joseph Zabner
- Department of Internal Medicine, University of Iowa, Iowa City, Iowa, United States of America
- * E-mail:
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Role of glucose in the expression of Cryptococcus neoformans antiphagocytic protein 1, App1. EUKARYOTIC CELL 2011; 10:293-301. [PMID: 21239626 DOI: 10.1128/ec.00252-10] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The cryptococcus-specific protein antiphagocytic protein 1 (App1) regulates Cryptococcus neoformans virulence by controlling macrophage-driven fungal phagocytosis. This is accomplished through complement receptors (CR), specifically CR3. When inhaled, C. neoformans can cause a life-threatening meningoencephalitis in immunocompromised patients. Because glucose starvation can significantly change the gene expression and virulence of C. neoformans and because App1 is critical for phagocytosis in the lung-a low-glucose environment-we investigated the role of glucose in App1 expression. We found that App1 was upregulated dramatically under low-glucose conditions, and it was upregulated when C. neoformans cells were incubated in bronchoalveolar lavage (BAL) fluid, serum, and cerebrospinal fluid, which are low-glucose environments. Characterization of App1's regulation based on mammalian lung physiology revealed that App1 is upregulated via both increases in transcription and increases in mRNA stability. Our data provide new insights regarding C. neoformans adaptations to low-glucose environments.
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Küpeli E, Ulubay G, Ulasli SS, Sahin T, Erayman Z, Gürsoy A. Metabolic syndrome is associated with increased risk of acute exacerbation of COPD: a preliminary study. Endocrine 2010; 38:76-82. [PMID: 20960105 DOI: 10.1007/s12020-010-9351-3] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/05/2010] [Accepted: 05/23/2010] [Indexed: 12/31/2022]
Abstract
Studies have confirmed correlation between metabolic syndrome (MetS) and chronic obstructive pulmonary disease (COPD). However, to date, no studies have analyzed correlation between exacerbations of COPD (ECOPD) and MetS. The aim of this preliminary study was to examine if presence of MetS increases the frequency and duration of ECOPD. Patients with COPD were prospectively enrolled and followed between March 2008 and September 2009. Medical records, pulmonary function tests, chest X-rays; laboratory test results were gathered to establish the presence of COPD and MetS. Patients were divided in two groups; with and without MetS. The ECOPD was defined as worsening of symptoms requiring increased use of rescue medications and/or need for either systemic steroids or antibiotics or that led to emergency room visit or hospitalizations during 12 months follow-up. A total of 106 patients were recruited, 29 with MetS and 77 without. The mean exacerbation of COPD frequency was 2.4 ± 0.8 in MetS group versus 0.68 ± 0.6 in the control group during the follow-up period (P < 0.001). Mean duration of each exacerbation was 7.5 ± 1.5 days in patients with MetS versus 5 ± 2.4 days in patients without. Serum C-reactive protein (r = 0.31, P = 0.001), fasting blood glucose (r = 0.55, P < 0.001), and triglycerides (r = 0.251, P = 0.01) were positively and significantly correlated with exacerbation frequency. This study demonstrates an association between ECOPD and its duration with the MetS. The systemic inflammation induced by common cytokines may explain the linkage between the two conditions.
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Affiliation(s)
- Elif Küpeli
- Department of Pulmonary Diseases, Baskent University Faculty of Medicine, Ankara, Turkey.
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