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Vasiljevs S, Witney AA, Baines DL. The presence of cystic fibrosis-related diabetes modifies the sputum microbiome in cystic fibrosis disease. Am J Physiol Lung Cell Mol Physiol 2024; 326:L125-L134. [PMID: 38084404 DOI: 10.1152/ajplung.00219.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Revised: 10/30/2023] [Accepted: 11/23/2023] [Indexed: 01/24/2024] Open
Abstract
Cystic fibrosis-related diabetes (CFRD) affects 40%-50% of adults with CF and is associated with a decline in respiratory health. The microbial flora of the lung is known to change with the development of CF disease, but how CFRD affects the microbiome has not been described. We analyzed the microbiome in sputa from 14 people with CF, 14 with CFRD, and two who were classed as pre-CFRD by extracting DNA and amplifying the variable V3-V4 region of the microbial 16S ribosomal RNA gene by PCR. Sequences were analyzed and sources were identified to genus level. We found that the α-diversity of the microbiome using Shannon's diversity index was increased in CFRD compared with CF. Bray Curtis dissimilarity analysis showed that there was separation of the microbiomes in CF and CFRD sputa. The most abundant phyla identified in the sputum samples were Firmicutes and Proteobacteria, Actinobacteriota and Bacteroidota, and the ratio of Firmicutes/Bacteroidota was reduced in CFRD compared with CF. Pseudomonas, Azhorizophilus, Porphyromonas, and Actinobacillus were more abundant in CFRD compared with CF, whereas Staphylococcus was less abundant. The relative abundance of these genera did not correlate with age; some correlated with a decline in FEV1/FVC but all correlated with hemoglobin A1C (HbA1c) indicating that development of CFRD mediates further changes to the respiratory microbiome in CF.NEW & NOTEWORTHY Cystic fibrosis-related diabetes (CFRD) is associated with a decline in respiratory health. We show for the first time that there was a change in the sputum microbiome of people with CFRD compared with CF that correlated with markers of raised blood glucose.
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Affiliation(s)
- Stanislavs Vasiljevs
- Institute for Infection and Immunity, St George's, University of London, London, United Kingdom
| | - Adam A Witney
- 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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2
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Walker AJ, Graham C, Greenwood M, Woodall M, Maeshima R, O’Hara-Wright M, Sanz DJ, Guerrini I, Aldossary AM, O’Callaghan C, Baines DL, Harrison PT, Hart SL. Molecular and functional correction of a deep intronic splicing mutation in CFTR by CRISPR-Cas9 gene editing. Mol Ther Methods Clin Dev 2023; 31:101140. [PMID: 38027060 PMCID: PMC10661860 DOI: 10.1016/j.omtm.2023.101140] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Accepted: 10/17/2023] [Indexed: 12/01/2023]
Abstract
Cystic fibrosis (CF) is an autosomal recessive disorder caused by mutations in the CFTR gene. The 10th most common mutation, c.3178-2477C>T (3849+10kb C>T), involves a cryptic, intronic splice site. This mutation was corrected in CF primary cells homozygous for this mutation by delivering pairs of guide RNAs (gRNAs) with Cas9 protein in ribonucleoprotein (RNP) complexes that introduce double-strand breaks to flanking sites to excise the 3849+10kb C>T mutation, followed by DNA repair by the non-homologous end-joining pathway, which functions in all cells of the airway epithelium. RNP complexes were delivered to CF basal epithelial cell by a non-viral, receptor-targeted nanocomplex comprising a formulation of targeting peptides and lipids. Canonical CFTR mRNA splicing was, thus, restored leading to the restoration of CFTR protein expression with concomitant restoration of electrophysiological function in airway epithelial air-liquid interface cultures. Off-target editing was not detected by Sanger sequencing of in silico-selected genomic sites with the highest sequence similarities to the gRNAs, although more sensitive unbiased whole genome sequencing methods would be required for possible translational developments. This approach could potentially be used to correct aberrant splicing signals in several other CF mutations and other genetic disorders where deep-intronic mutations are pathogenic.
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Affiliation(s)
- Amy J. Walker
- Genetics and Genomic Medicine Department, UCL Great Ormond Street Institute of Child Health, London, UK
| | - Carina Graham
- Genetics and Genomic Medicine Department, UCL Great Ormond Street Institute of Child Health, London, UK
| | - Miriam Greenwood
- Genetics and Genomic Medicine Department, UCL Great Ormond Street Institute of Child Health, London, UK
| | - Maximillian Woodall
- Institute for Infection and Immunity, St. George’s, University of London, London, UK
| | - Ruhina Maeshima
- Genetics and Genomic Medicine Department, UCL Great Ormond Street Institute of Child Health, London, UK
| | - Michelle O’Hara-Wright
- Genetics and Genomic Medicine Department, UCL Great Ormond Street Institute of Child Health, London, UK
| | - David J. Sanz
- Department of Physiology, BioSciences Institute, University College Cork, Cork, Ireland
| | - Ileana Guerrini
- Genetics and Genomic Medicine Department, UCL Great Ormond Street Institute of Child Health, London, UK
| | - Ahmad M. Aldossary
- Genetics and Genomic Medicine Department, UCL Great Ormond Street Institute of Child Health, London, UK
| | - Christopher O’Callaghan
- Infection, Immunity & Inflammation Department, UCL Great Ormond Street Institute of Child Health, London, UK
| | - Deborah L. Baines
- Institute for Infection and Immunity, St. George’s, University of London, London, UK
| | - Patrick T. Harrison
- Department of Physiology, BioSciences Institute, University College Cork, Cork, Ireland
| | - Stephen L. Hart
- Genetics and Genomic Medicine Department, UCL Great Ormond Street Institute of Child Health, London, UK
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Kalsi KK, Jackson S, Baines DL. Lipoxin receptor agonist and inhibition of LTA4 hydrolase prevent tight junction disruption caused by P. aeruginosa filtrate in airway epithelial cells. PLoS One 2023; 18:e0287183. [PMID: 37406028 PMCID: PMC10321624 DOI: 10.1371/journal.pone.0287183] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Accepted: 05/31/2023] [Indexed: 07/07/2023] Open
Abstract
Airway diseases can disrupt tight junction proteins, compromising the epithelial barrier and making it more permeable to pathogens. In people with pulmonary disease who are prone to infection with Pseudomonas aeruginosa, pro-inflammatory leukotrienes are increased and anti-inflammatory lipoxins are decreased. Upregulation of lipoxins is effective in counteracting inflammation and infection. However, whether combining a lipoxin receptor agonist with a specific leukotriene A4 hydrolase (LTA4H) inhibitor could enhance these protective effects has not to our knowledge been investigated. Therefore, we explored the effect of lipoxin receptor agonist BML-111 and JNJ26993135 a specific LTA4H inhibitor that prevents the production of pro-inflammatory LTB4 on tight junction proteins disrupted by P. aeruginosa filtrate (PAF) in human airway epithelial cell lines H441 and 16HBE-14o. Pre-treatment with BML-111 prevented an increase in epithelial permeability induced by PAF and conserved ZO-1 and claudin-1 at the cell junctions. JNJ26993135 similarly prevented the increased permeability induced by PAF, restored ZO-1 and E-cadherin and reduced IL-8 but not IL-6. Cells pre-treated with BML-111 plus JNJ26993135 restored TEER and permeability, ZO-1 and claudin-1 to the cell junctions. Taken together, these data indicate that the combination of a lipoxin receptor agonist with a LTA4H inhibitor could provide a more potent therapy.
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Affiliation(s)
- Kameljit K. Kalsi
- Institute for Infection and Immunity, St George’s University of London, London, United Kingdom
| | - Sonya Jackson
- Translational Science and Experimental Medicine Research and Early Development, Respiratory, Inflammation & Autoimmune (RIA), Biopharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden
| | - Deborah L. Baines
- Institute for Infection and Immunity, St George’s University of London, London, United Kingdom
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Wu T, Wrennall JA, Dang H, Baines DL, Tarran R. Passaging Primary Human Bronchial Epithelia Reduces CFTR-Mediated Fluid Transport and Alters mRNA Expression. Cells 2023; 12:997. [PMID: 37048070 PMCID: PMC10092965 DOI: 10.3390/cells12070997] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Revised: 03/17/2023] [Accepted: 03/21/2023] [Indexed: 04/14/2023] Open
Abstract
Primary human bronchial epithelial cultures (HBECs) are used to study airway physiology, disease, and drug development. HBECs often replicate human airway physiology/pathophysiology. Indeed, in the search for cystic fibrosis (CF) transmembrane conductance regulator (CFTR) therapies, HBECs were seen as the "gold standard" in preclinical studies. However, HBECs are not without their limitations: they are non-immortalized and the requirement for human donors, especially those with rare genetic mutations, can make HBECs expensive and/or difficult to source. For these reasons, researchers may opt to expand HBECs by passaging. This practice is common, but to date, there has not been a robust analysis of the impact of expanding HBECs on their phenotype. Here, we used functional studies of airway surface liquid (ASL) homeostasis, epithelial barrier properties, and RNA-seq and Western blotting to investigate HBEC changes over two passage cycles. We found that passaging impaired CFTR-mediated ASL secretion and led to a reduction in the plasma membrane expression of the epithelial sodium channel (ENaC) and CFTR. Passaging also resulted in an increase in transepithelial resistance and a decrease in epithelial water permeability. We then looked for changes at the mRNA level and found that passaging significantly affected 323 genes, including genes involved in inflammation, cell growth, and extracellular matrix remodeling. Collectively, these data highlight the potential for HBEC expansion to impact research findings.
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Affiliation(s)
- Tongde Wu
- Department of Cell Biology & Physiology, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Joe A. Wrennall
- Department of Cell Biology & Physiology, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Hong Dang
- Marsico Lung Institute, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Deborah L. Baines
- Institute for Infection and Immunity, St George’s, University of London, Tooting, London SW17 0RE, UK
| | - Robert Tarran
- Department of Cell Biology & Physiology, University of North Carolina, Chapel Hill, NC 27599, USA
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Baines DL, Vasiljevs S, Kalsi KK. Getting sweeter: new evidence for glucose transporters in specific cell types of the airway? Am J Physiol Cell Physiol 2023; 324:C153-C166. [PMID: 36409177 PMCID: PMC9829484 DOI: 10.1152/ajpcell.00140.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
New technologies such as single-cell RNA sequencing (scRNAseq) has enabled identification of the mRNA transcripts expressed by individual cells. This review provides insight from recent scRNAseq studies on the expression of glucose transporters in the epithelial cells of the airway epithelium from trachea to alveolus. The number of studies analyzed was limited, not all reported the full range of glucose transporters and there were differences between cells freshly isolated from the airways and those grown in vitro. Furthermore, glucose transporter mRNA transcripts were expressed at lower levels than other epithelial marker genes. Nevertheless, these studies highlighted that there were differences in cellular expression of glucose transporters. GLUT1 was the most abundant of the broadly expressed transporters that included GLUT8, 10, and 13. GLUT9 transcripts were more common in basal cells and GLUT12 in ionocytes/ciliated cells. In addition to alveolar cells, SGLT1 transcripts were present in secretory cells. GLUT3 mRNA transcripts were expressed in a cell cluster that expressed monocarboxylate (MCT2) transporters. Such distributions likely underlie cell-specific metabolic requirements to support proliferation, ion transport, mucous secretion, environment sensing, and airway glucose homeostasis. These studies have also highlighted the role of glucose transporters in the movement of dehydroascorbic acid/vitamin C/myoinositol/urate, which are factors important to the innate immune properties of the airways. Discrepancies remain between detection of mRNAs, protein, and function of glucose transporters in the lungs. However, collation of the data from further scRNAseq studies may provide a better consensus and understanding, supported by qPCR, immunohistochemistry, and functional experiments.
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Affiliation(s)
- Deborah L. Baines
- Institute for Infection and Immunity, St George’s, University of London, London, United Kingdom
| | - Stanislavs Vasiljevs
- Institute for Infection and Immunity, St George’s, University of London, London, United Kingdom
| | - Kameljit K. Kalsi
- Institute for Infection and Immunity, St George’s, University of London, London, United Kingdom
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Woodall M, Reidel B, Kesimer M, Tarran R, Baines DL. Culture with apically applied healthy or disease sputum alters the airway surface liquid proteome and ion transport across human bronchial epithelial cells. Am J Physiol Cell Physiol 2021; 321:C954-C963. [PMID: 34613844 PMCID: PMC8714986 DOI: 10.1152/ajpcell.00234.2021] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Airway secretions contain many signaling molecules and peptides/proteins that are
not found in airway surface liquid (ASL) generated by normal human bronchial
epithelial cells (NHBEs) in vitro. These play a key role in innate defense and
mediate communication between the epithelium, the immune cells, and the external
environment. We investigated how culture of NHBE with apically applied
secretions from healthy or diseased (cystic fibrosis, CF) lungs affected
epithelial function with a view to providing better in vitro models of the in
vivo environment. NHBEs from 6 to 8 different donors were cultured at air-liquid
interface (ALI), with apically applied sputum from normal healthy donors (normal
lung sputum; NLS) or CF donors (CFS) for 2–4 h, 48 h, or with sputum
reapplied over 48 h. Proteomics analysis was carried out on the sputa and on the
NHBE ASL before and after culture with sputa. Transepithelial electrical
resistance (TEER), short circuit current (Isc), and changes to ASL
height were measured. There were 71 proteins common to both sputa but not ASL.
The protease:protease inhibitor balance was increased in CFS compared with NLS
and ASL. Culture of NHBE with sputa for 48 h identified additional factors not
present in NLS, CFS, or ASL alone. Culture with either NLS or CFS for 48 h
increased cystic fibrosis transmembrane regulator (CFTR) activity,
calcium-activated chloride channel (CaCC) activity, and changed ASL height.
These data indicate that culture with healthy or disease sputum changes the
proteomic profile of ASL and ion transport properties of NHBE and this may
increase physiological relevance when using in vitro airway models.
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Affiliation(s)
- Maximillian Woodall
- Institute for Infection and Immunity, St George's, University of London, Cranmer Terrace, Tooting, London, United Kingdom
| | - Boris Reidel
- Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Mehmet Kesimer
- Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Robert Tarran
- Department of Cell Biology & Physiology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Deborah L Baines
- Institute for Infection and Immunity, St George's, University of London, Cranmer Terrace, Tooting, London, United Kingdom
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Bearham J, Krutrök N, Lindberg B, Woodall M, Astrand A, Taylor JD, Biggart M, Vasiljevs S, Tarran R, Baines DL. A modified fluorescent sensor for reporting glucose concentration in the airway lumen. PLoS One 2021; 16:e0254248. [PMID: 34242292 PMCID: PMC8270177 DOI: 10.1371/journal.pone.0254248] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Accepted: 06/23/2021] [Indexed: 11/19/2022] Open
Abstract
We have modified the periplasmic Escherichia coli glucose/galactose binding protein (GBP) and labelled with environmentally sensitive fluorophores to further explore its potential as a sensor for the evaluation of glucose concentration in airway surface liquid (ASL). We identified E149C/A213R GBP labelled with N,N’-Dimethyl-N-(iodoacetyl)-N’-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)ethylenediamine (IANBD, emission wavelength maximum 536nm) with a Kd for D-glucose of 1.02mM and a fluorescence dynamic range of 5.8. This sensor was specific for D-glucose and exhibited fluorescence stability in experiments for several hours. The use of E149C/A213R GBP-IANBD in the ASL of airway cells grown at air-liquid-interface (ALI) detected an increase in glucose concentration 10 minutes after raising basolateral glucose from 5 to 15mM. This sensor also reported a greater change in ASL glucose concentration in response to increased basolateral glucose in H441 airway cells compared to human bronchial epithelial cells (HBEC) and there was less variability with HBEC data than that of H441 indicating that HBEC more effectively regulate glucose movement into the ASL. The sensor detected glucose in bronchoalveolar lavage fluid (BALf) from diabetic db/db mice but not normoglycaemic wildtype mice, indicating limited sensitivity of the sensor at glucose concentrations <50μM. Using nasal inhalation of the sensor and spectral unmixing to generate images, E149C/A213R GBP-IANBD fluorescence was detected in luminal regions of cryosections of the murine distal lung that was greater in db/db than wildtype mice. In conclusion, this sensor provides a useful tool for further development to measure luminal glucose concentration in models of lung/airway to explore how this may change in disease.
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Affiliation(s)
- Jade Bearham
- Institute for Infection and Immunity, St George’s University of London, London, United Kingdom
| | - Nina Krutrök
- Research and Early Development, Respiratory & Immunology, BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden
| | - Botilda Lindberg
- Research and Early Development, Respiratory & Immunology, BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden
| | - Maximillian Woodall
- Institute for Infection and Immunity, St George’s University of London, London, United Kingdom
| | - Annika Astrand
- Research and Early Development, Respiratory & Immunology, BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden
| | - John D. Taylor
- Research and Early Development, Respiratory & Immunology, BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden
| | - Matthew Biggart
- Institute for Infection and Immunity, St George’s University of London, London, United Kingdom
| | - Stanislavs Vasiljevs
- Institute for Infection and Immunity, St George’s University of London, London, United Kingdom
| | - Robert Tarran
- Department of Cell Biology & Physiology, University of North Carolina, Chapel Hill, North Carolina, United States of America
| | - Deborah L. Baines
- Institute for Infection and Immunity, St George’s University of London, London, United Kingdom
- * E-mail:
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Affiliation(s)
- Deborah L Baines
- Institute for Infection and Immunity, St George's, University of London, Cranmer Terrace, Tooting, London, UK
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9
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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Kalsi KK, Garnett JP, Patkee W, Weekes A, Dockrell ME, Baker EH, Baines DL. Metformin attenuates the effect of Staphylococcus aureus on airway tight junctions by increasing PKCζ-mediated phosphorylation of occludin. J Cell Mol Med 2018; 23:317-327. [PMID: 30450773 PMCID: PMC6307806 DOI: 10.1111/jcmm.13929] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2018] [Accepted: 08/29/2018] [Indexed: 01/03/2023] Open
Abstract
Airway epithelial tight junction (TJ) proteins form a resistive barrier to the external environment, however, during respiratory bacterial infection TJs become disrupted compromising barrier function. This promotes glucose flux/accumulation into the lumen which acts as a nutrient source for bacterial growth. Metformin used for the treatment of diabetes increases transepithelial resistance (TEER) and partially prevents the effect of bacteria but the mechanisms of action are unclear. We investigated the effect of metformin and Staphylococcus aureus on TJ proteins, zonula occludins (ZO)-1 and occludin in human airway epithelial cells (H441). We also explored the role of AMP-activated protein kinase (AMPK) and PKCζ in metformin-induced effects. Pretreatment with metformin prevented the S. aureus-induced changes in ZO-1 and occludin. Metformin also promoted increased abundance of full length over smaller cleaved occludin proteins. The nonspecific PKC inhibitor staurosporine reduced TEER but did not prevent the effect of metformin indicating that the pathway may involve atypical PKC isoforms. Investigation of TJ reassembly after calcium depletion showed that metformin increased TEER more rapidly and promoted the abundance and localization of occludin at the TJ. These effects were inhibited by the AMPK inhibitor, compound C and the PKCζ pseudosubstrate inhibitor (PSI). Metformin increased phosphorylation of occludin and acetyl-coA-carboxylase but only the former was prevented by PSI. This study demonstrates that metformin improves TJ barrier function by promoting the abundance and assembly of full length occludin at the TJ and that this process involves phosphorylation of the protein via an AMPK-PKCζ pathway.
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Affiliation(s)
- Kameljit K. Kalsi
- Institute for Infection and ImmunitySt George's University of LondonLondonUK
| | - James P. Garnett
- Institute for Infection and ImmunitySt George's University of LondonLondonUK
- Present address:
Institute of Cellular MedicineNewcastle UniversityNewcastle upon TyneUK
| | - Wishwanath Patkee
- Institute for Infection and ImmunitySt George's University of LondonLondonUK
| | - Alexina Weekes
- Institute for Infection and ImmunitySt George's University of LondonLondonUK
| | - Mark E. Dockrell
- South West Thames Institute for Renal ResearchSt Helier HospitalCarshaltonUK
| | - Emma H. Baker
- Institute for Infection and ImmunitySt George's University of LondonLondonUK
| | - Deborah L. Baines
- Institute for Infection and ImmunitySt George's University of LondonLondonUK
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Kellezi B, Baines DL, Coupland C, Beckett K, Barnes J, Sleney J, Christie N, Kendrick D. The impact of injuries on health service resource use and costs in primary and secondary care in the English NHS. J Public Health (Oxf) 2018; 38:e464-e471. [PMID: 28158513 DOI: 10.1093/pubmed/fdv173] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Affiliation(s)
| | - D L Baines
- Centre for Technology Enabled Health Research, Coventry University, Coventry CV1 5FB, UK
| | - C Coupland
- Division of Primary Care, University Park, Nottingham NG7 2RD, UK
| | - K Beckett
- Centre for Research in Clinical Practice, University of the West of England/University Hospitals Bristol NHS Foundation Trust Education Centre, Bristol BS2 8AE, UK
| | - J Barnes
- Design School, Loughborough University, Loughborough LE11 3TU, UK
| | - J Sleney
- Faculty of Arts and Human Sciences, University of Surrey, Surrey, UK
| | - N Christie
- Centre for Transport Studies, University College London, London WC1E 6BT, UK
| | - D Kendrick
- Division of Primary Care, University Park, Nottingham NG7 2RD, UK
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Tagalakis AD, Munye MM, Ivanova R, Chen H, Smith CM, Aldossary AM, Rosa LZ, Moulding D, Barnes JL, Kafetzis KN, Jones SA, Baines DL, Moss GWJ, O'Callaghan C, McAnulty RJ, Hart SL. Effective silencing of ENaC by siRNA delivered with epithelial-targeted nanocomplexes in human cystic fibrosis cells and in mouse lung. Thorax 2018; 73:847-856. [PMID: 29748250 PMCID: PMC6109249 DOI: 10.1136/thoraxjnl-2017-210670] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Revised: 04/08/2018] [Accepted: 04/09/2018] [Indexed: 12/21/2022]
Abstract
INTRODUCTION Loss of the cystic fibrosis transmembrane conductance regulator in cystic fibrosis (CF) leads to hyperabsorption of sodium and fluid from the airway due to upregulation of the epithelial sodium channel (ENaC). Thickened mucus and depleted airway surface liquid (ASL) then lead to impaired mucociliary clearance. ENaC regulation is thus a promising target for CF therapy. Our aim was to develop siRNA nanocomplexes that mediate effective silencing of airway epithelial ENaC in vitro and in vivo with functional correction of epithelial ion and fluid transport. METHODS We investigated translocation of nanocomplexes through mucus and their transfection efficiency in primary CF epithelial cells grown at air-liquid interface (ALI).Short interfering RNA (SiRNA)-mediated silencing was examined by quantitative RT-PCR and western analysis of ENaC. Transepithelial potential (Vt), short circuit current (Isc), ASL depth and ciliary beat frequency (CBF) were measured for functional analysis. Inflammation was analysed by histological analysis of normal mouse lung tissue sections. RESULTS Nanocomplexes translocated more rapidly than siRNA alone through mucus. Transfections of primary CF epithelial cells with nanocomplexes targeting αENaC siRNA, reduced αENaC and βENaC mRNA by 30%. Transfections reduced Vt, the amiloride-sensitive Isc and mucus protein concentration while increasing ASL depth and CBF to normal levels. A single dose of siRNA in mouse lung silenced ENaC by approximately 30%, which persisted for at least 7 days. Three doses of siRNA increased silencing to approximately 50%. CONCLUSION Nanoparticle-mediated delivery of ENaCsiRNA to ALI cultures corrected aspects of the mucociliary defect in human CF cells and offers effective delivery and silencing in vivo.
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Affiliation(s)
- Aristides D Tagalakis
- Experimental and Personalised Medicine Section, UCL Great Ormond Street Institute of Child Health, London, UK
| | - Mustafa M Munye
- Experimental and Personalised Medicine Section, UCL Great Ormond Street Institute of Child Health, London, UK
| | - Rositsa Ivanova
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, UK
| | - Hanpeng Chen
- Institute of Pharmaceutical Science, Faculty of Life Science and Medicine, King's College London, London, UK
| | - Claire M Smith
- Respiratory, Critical Care and Anaesthesia, UCL Great Ormond Street Institute of Child Health, London, UK
| | - Ahmad M Aldossary
- Experimental and Personalised Medicine Section, UCL Great Ormond Street Institute of Child Health, London, UK
| | - Luca Z Rosa
- Experimental and Personalised Medicine Section, UCL Great Ormond Street Institute of Child Health, London, UK
| | - Dale Moulding
- UCL Great Ormond Street Institute of Child Health, London, UK
| | | | - Konstantinos N Kafetzis
- Experimental and Personalised Medicine Section, UCL Great Ormond Street Institute of Child Health, London, UK
| | - Stuart A Jones
- Institute of Pharmaceutical Science, Faculty of Life Science and Medicine, King's College London, London, UK
| | - Deborah L Baines
- Institute of Infection and Immunity, St George's University of London, London, UK
| | - Guy W J Moss
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, UK
| | - Christopher O'Callaghan
- Respiratory, Critical Care and Anaesthesia, UCL Great Ormond Street Institute of Child Health, London, UK
| | - Robin J McAnulty
- UCL Respiratory Centre for Inflammation and Tissue Repair, London, UK
| | - Stephen L Hart
- Experimental and Personalised Medicine Section, UCL Great Ormond Street Institute of Child Health, London, UK
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13
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Holmberg CN, Åstrand A, Wingren C, Garnett JP, Mayer G, Taylor JD, Baker EH, Baines DL. Differential Effect of LPS on Glucose, Lactate and Inflammatory Markers in the Lungs of Normal and Diabetic Mice. J Pulm Respir Med 2017; 2017:PROA-101. [PMID: 29938126 PMCID: PMC6010169] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Elevation of blood glucose results in increased glucose in the fluid that lines the surface of the airways and this is associated with an increased susceptibility to infection with respiratory pathogens. Infection induces an inflammatory response in the lung, but how this is altered by hyperglycemia and how this affects glucose, lactate and cytokine concentrations in the airway surface liquid is not understood. We used Wild Type (WT) and glucokinase heterozygote (GK+/-) mice to investigate the effect of hyperglycemia, with and without LPS-induced inflammatory responses, on airway glucose, lactate, inflammatory cells and cytokines measured in Bronchoalveolar Lavage Fluid (BALF). We found that glucose and lactate concentrations in BALF were elevated in GK+/- compared to WT mice and that there was a direct correlation between blood glucose and BALF glucose concentrations. LPS challenge increased BALF inflammatory cell numbers and this correlated with decreased glucose and increased lactate concentrations although the effect was less in GK+/- compared to WT mice. All cytokines measured (except IL-2) increased in BALF with LPS challenge. However, concentrations of TNFα, INFγ, IL-1β and IL-2 were less in GK+/- compared to WT mice. This study shows that the normal glucose/lactate environment of the airway surface liquid is altered by hyperglycemia and the inflammatory response. These data indicate that inflammatory cells utilize BALF glucose and that production of lactate and cytokines is compromised in hyperglycemic GK+/- mice.
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Affiliation(s)
- Cecilia Nagorny Holmberg
- Respiratory, Inflammation and Autoimmunity Innovative Medicines Research Unit, AstraZeneca Gothenburg, Pepparedsleden, Mölndal, Sweden
| | - Annika Åstrand
- Respiratory, Inflammation and Autoimmunity Innovative Medicines Research Unit, AstraZeneca Gothenburg, Pepparedsleden, Mölndal, Sweden
| | - Cecilia Wingren
- Respiratory, Inflammation and Autoimmunity Innovative Medicines Research Unit, AstraZeneca Gothenburg, Pepparedsleden, Mölndal, Sweden
| | - James P Garnett
- Institute for Infection and Immunity, St George’s, University of London, London, UK
| | - Gaëll Mayer
- Respiratory, Inflammation and Autoimmunity Innovative Medicines Research Unit, AstraZeneca Gothenburg, Pepparedsleden, Mölndal, Sweden
| | - John D Taylor
- Respiratory, Inflammation and Autoimmunity Innovative Medicines Research Unit, AstraZeneca Gothenburg, Pepparedsleden, Mölndal, Sweden
| | - 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
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14
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Åstrand A, Wingren C, Benjamin A, Tregoning JS, Garnett JP, Groves H, Gill S, Orogo‐Wenn M, Lundqvist AJ, Walters D, Smith DM, Taylor JD, Baker EH, Baines DL. Dapagliflozin-lowered blood glucose reduces respiratory Pseudomonas aeruginosa infection in diabetic mice. Br J Pharmacol 2017; 174:836-847. [PMID: 28192604 PMCID: PMC5386993 DOI: 10.1111/bph.13741] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2016] [Revised: 01/24/2017] [Accepted: 02/07/2017] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND AND PURPOSE Hyperglycaemia increases glucose concentrations in airway surface liquid and increases the risk of pulmonary Pseudomonas aeruginosa infection. We determined whether reduction of blood and airway glucose concentrations by the anti-diabetic drug dapagliflozin could reduce P. aeruginosa growth/survival in the lungs of diabetic mice. EXPERIMENTAL APPROACH The effect of dapagliflozin on blood and airway glucose concentration, the inflammatory response and infection were investigated in C57BL/6J (wild type, WT) or leptin receptor-deficient (db/db) mice, treated orally with dapagliflozin prior to intranasal dosing with LPS or inoculation with P. aeruginosa. Pulmonary glucose transport and fluid absorption were investigated in Wistar rats using the perfused fluid-filled lung technique. KEY RESULTS Fasting blood, airway glucose and lactate concentrations were elevated in the db/db mouse lung. LPS challenge increased inflammatory cells in bronchoalveolar lavage fluid from WT and db/db mice with and without dapagliflozin treatment. P. aeruginosa colony-forming units (CFU) were increased in db/db lungs. Pretreatment with dapagliflozin reduced blood and bronchoalveolar lavage glucose concentrations and P. aeruginosa CFU in db/db mice towards those seen in WT. Dapagliflozin had no adverse effects on the inflammatory response in the mouse or pulmonary glucose transport or fluid absorption in the rat lung. CONCLUSION AND IMPLICATIONS Pharmacological lowering of blood glucose with dapagliflozin effectively reduced P. aeruginosa infection in the lungs of diabetic mice and had no adverse pulmonary effects in the rat. Dapagliflozin has potential to reduce the use, or augment the effect, of antimicrobials in the prevention or treatment of pulmonary infection.
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Affiliation(s)
- Annika Åstrand
- Respiratory, Inflammation and Autoimmunity Innovative Medicines Research UnitAstraZeneca GothenburgMölndalSweden
| | - Cecilia Wingren
- Respiratory, Inflammation and Autoimmunity Innovative Medicines Research UnitAstraZeneca GothenburgMölndalSweden
| | - Audra Benjamin
- Institute for Infection and ImmunitySt George's, University of LondonLondonUK
| | - John S Tregoning
- Mucosal Infection & Immunity Group, Section of VirologyImperial College London, St Mary's CampusLondonUK
| | - James P Garnett
- Institute for Infection and ImmunitySt George's, University of LondonLondonUK
| | - Helen Groves
- Mucosal Infection & Immunity Group, Section of VirologyImperial College London, St Mary's CampusLondonUK
| | - Simren Gill
- Mucosal Infection & Immunity Group, Section of VirologyImperial College London, St Mary's CampusLondonUK
| | - Maria Orogo‐Wenn
- Institute for Infection and ImmunitySt George's, University of LondonLondonUK
| | - Anders J Lundqvist
- Respiratory, Inflammation and Autoimmunity Innovative Medicines Research UnitAstraZeneca GothenburgMölndalSweden
| | - Dafydd Walters
- Institute for Infection and ImmunitySt George's, University of LondonLondonUK
| | - David M Smith
- Cardiovascular & Metabolic Diseases Innovative Medicines Research UnitAstraZeneca GothenburgMölndalSweden
| | - John D Taylor
- Respiratory, Inflammation and Autoimmunity Innovative Medicines Research UnitAstraZeneca GothenburgMölndalSweden
| | - Emma H Baker
- Institute for Infection and ImmunitySt George's, University of LondonLondonUK
| | - Deborah L Baines
- Institute for Infection and ImmunitySt George's, University of LondonLondonUK
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15
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Munye MM, Shoemark A, Hirst RA, Delhove JM, Sharp TV, McKay TR, O'Callaghan C, Baines DL, Howe SJ, Hart SL. BMI-1 extends proliferative potential of human bronchial epithelial cells while retaining their mucociliary differentiation capacity. Am J Physiol Lung Cell Mol Physiol 2016; 312:L258-L267. [PMID: 27979861 DOI: 10.1152/ajplung.00471.2016] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Revised: 12/13/2016] [Accepted: 12/14/2016] [Indexed: 12/15/2022] Open
Abstract
Air-liquid interface (ALI) culture of primary airway epithelial cells enables mucociliary differentiation providing an in vitro model of the human airway, but their proliferative potential is limited. To extend proliferation, these cells were previously transduced with viral oncogenes or mouse Bmi-1 + hTERT, but the resultant cell lines did not undergo mucociliary differentiation. We hypothesized that use of human BMI-1 alone would increase the proliferative potential of bronchial epithelial cells while retaining their mucociliary differentiation potential. Cystic fibrosis (CF) and non-CF bronchial epithelial cells were transduced by lentivirus with BMI-1 and then their morphology, replication kinetics, and karyotype were assessed. When differentiated at ALI, mucin production, ciliary function, and transepithelial electrophysiology were measured. Finally, shRNA knockdown of DNAH5 in BMI-1 cells was used to model primary ciliary dyskinesia (PCD). BMI-1-transduced basal cells showed normal cell morphology, karyotype, and doubling times despite extensive passaging. The cell lines underwent mucociliary differentiation when cultured at ALI with abundant ciliation and production of the gel-forming mucins MUC5AC and MUC5B evident. Cilia displayed a normal beat frequency and 9+2 ultrastructure. Electrophysiological characteristics of BMI-1-transduced cells were similar to those of untransduced cells. shRNA knockdown of DNAH5 in BMI-1 cells produced immotile cilia and absence of DNAH5 in the ciliary axoneme as seen in cells from patients with PCD. BMI-1 delayed senescence in bronchial epithelial cells, increasing their proliferative potential but maintaining mucociliary differentiation at ALI. We have shown these cells are amenable to genetic manipulation and can be used to produce novel disease models for research and dissemination.
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Affiliation(s)
- Mustafa M Munye
- University College London Great Ormond Street Institute of Child Health, London, United Kingdom
| | - Amelia Shoemark
- Imperial College London, UK Electron Microscopy Department, Royal Brompton and Harefield NHS Foundation Trust, London, United Kingdom
| | - Robert A Hirst
- Primary Ciliary Dyskinesia Centre Department of Infection, Immunity and Inflammation, University of Leicester, Leicester, United Kingdom
| | - Juliette M Delhove
- University College London Great Ormond Street Institute of Child Health, London, United Kingdom
| | - Tyson V Sharp
- Centre for Molecular Oncology, Barts Cancer Institute, Queen Mary University of London, London, United Kingdom
| | - Tristan R McKay
- School of Healthcare Science, Manchester Metropolitan University, Manchester, United Kingdom; and
| | - Christopher O'Callaghan
- University College London Great Ormond Street Institute of Child Health, London, United Kingdom
| | - Deborah L Baines
- Institute for Infection and Immunity, St George's, University of London, London, United Kingdom
| | - Steven J Howe
- University College London Great Ormond Street Institute of Child Health, London, United Kingdom
| | - Stephen L Hart
- University College London Great Ormond Street Institute of Child Health, London, United Kingdom;
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16
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Garnett JP, Kalsi KK, Sobotta M, Bearham J, Carr G, Powell J, Brodlie M, Ward C, Tarran R, Baines DL. Hyperglycaemia and Pseudomonas aeruginosa acidify cystic fibrosis airway surface liquid by elevating epithelial monocarboxylate transporter 2 dependent lactate-H + secretion. Sci Rep 2016; 6:37955. [PMID: 27897253 PMCID: PMC5126573 DOI: 10.1038/srep37955] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2016] [Accepted: 11/02/2016] [Indexed: 01/26/2023] Open
Abstract
The cystic fibrosis (CF) airway surface liquid (ASL) provides a nutrient rich environment for bacterial growth including elevated glucose, which together with defective bacterial killing due to aberrant HCO3- transport and acidic ASL, make the CF airways susceptible to colonisation by respiratory pathogens such as Pseudomonas aeruginosa. Approximately half of adults with CF have CF related diabetes (CFRD) and this is associated with increased respiratory decline. CF ASL contains elevated lactate concentrations and hyperglycaemia can also increase ASL lactate. We show that primary human bronchial epithelial (HBE) cells secrete lactate into ASL, which is elevated in hyperglycaemia. This leads to ASL acidification in CFHBE, which could only be mimicked in non-CF HBE following HCO3- removal. Hyperglycaemia-induced changes in ASL lactate and pH were exacerbated by the presence of P. aeruginosa and were attenuated by inhibition of monocarboxylate lactate-H+ co-transporters (MCTs) with AR-C155858. We conclude that hyperglycaemia and P. aeruginosa induce a metabolic shift which increases lactate generation and efflux into ASL via epithelial MCT2 transporters. Normal airways compensate for MCT-driven H+ secretion by secreting HCO3-, a process which is dysfunctional in CF airway epithelium leading to ASL acidification and that these processes may contribute to worsening respiratory disease in CFRD.
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Affiliation(s)
- James Peter Garnett
- Institute of Cellular Medicine, Newcastle University, Newcastle-upon-Tyne, UK
- Immunology & Respiratory Diseases Research, Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach an der Riss, Germany
| | - Kameljit K. Kalsi
- Institute for Infection and Immunity, St George’s, University of London, Tooting, London, UK
| | - Mirko Sobotta
- Immunology & Respiratory Diseases Research, Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach an der Riss, Germany
| | - Jade Bearham
- Institute for Infection and Immunity, St George’s, University of London, Tooting, London, UK
| | - Georgina Carr
- Institute of Cellular Medicine, Newcastle University, Newcastle-upon-Tyne, UK
| | - Jason Powell
- Institute of Cellular Medicine, Newcastle University, Newcastle-upon-Tyne, UK
| | - Malcolm Brodlie
- Institute of Cellular Medicine, Newcastle University, Newcastle-upon-Tyne, UK
| | - Christopher Ward
- Institute of Cellular Medicine, Newcastle University, Newcastle-upon-Tyne, UK
| | - Robert Tarran
- Cystic Fibrosis Centre/Marisco Lung Institute, University of North Carolina, Chapel Hill, NC, USA
| | - Deborah L. Baines
- Institute for Infection and Immunity, St George’s, University of London, Tooting, London, UK
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17
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Gill SK, Hui K, Farne H, Garnett JP, Baines DL, Moore LSP, 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: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [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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18
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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19
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Zuckermann AME, La Ragione RM, Baines DL, Williams RSB. Valproic acid protects against haemorrhagic shock-induced signalling changes via PPARγ activation in an in vitro model. Br J Pharmacol 2015; 172:5306-17. [PMID: 26333042 PMCID: PMC5123713 DOI: 10.1111/bph.13320] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2015] [Revised: 08/04/2015] [Accepted: 08/24/2015] [Indexed: 01/29/2023] Open
Abstract
BACKGROUND AND PURPOSE Valproic acid (VPA), a widely used epilepsy and bipolar disorder treatment, provides acute protection against haemorrhagic shock-induced mortality in a range of in vivo models through an unknown mechanism. In the liver, this effect occurs with a concomitant protection against a decrease in GSK3β-Ser(9) phosphorylation. Here, we developed an in vitro model to investigate this protective effect of VPA and define a molecular mechanism. EXPERIMENTAL APPROACH The human hepatocarcinoma cell line (Huh7) was exposed to conditions occurring during haemorrhagic shock (hypoxia, hypercapnia and hypothermia) to investigate the changes in GSK3β-Ser(9) phosphorylation for a 4 h period following treatment with VPA, related congeners, PPAR agonists, antagonists and siRNA. KEY RESULTS Huh7 cells undergoing combined hypoxia, hypercapnia, and hypothermia reproduced the reduced GSK3β-Ser(9) phosphorylation shown in vivo during haemorrhagic shock, and this change was blocked by VPA. The protective effect occurred through upstream PTEN and Akt signalling, and prevented downstream β-catenin degradation while increasing histone 2/3 acetylation. This effect was reproduced by several VPA-related compounds with known PPARγ agonist activity, independent of histone deacetylase (HDAC) inhibitory activity. Specific pharmacological inhibition (by T0070907) or knockdown of PPARγ blocked the protective effect of VPA against these signalling changes and apoptosis. In addition, specific activation of PPARγ using ciglitazone reproduced the changes induced by VPA in haemorrhagic shock-like conditions. CONCLUSION AND IMPLICATIONS Changes in GSK3β-Ser(9) phosphorylation in in vivo haemorrhagic shock models can be modelled in vitro, and this has identified a role for PPARγ activation in the protective role of VPA.
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Affiliation(s)
- Alexandra M E Zuckermann
- Centre for Biomedical Sciences, School of Biological Sciences, Royal Holloway University of London, Egham, TW20 0EX, UK
| | - Roberto M La Ragione
- School of Veterinary Medicine, University of Surrey, Guildford Surrey, GU2 7XH, UK
| | - Deborah L Baines
- Institute for Infection and Immunity, St George's University of London, London, SW17 0RE, UK
| | - Robin S B Williams
- Centre for Biomedical Sciences, School of Biological Sciences, Royal Holloway University of London, Egham, TW20 0EX, UK
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20
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Sofat N, Wait R, Robertson SD, Baines DL, Baker EH. Interaction between extracellular matrix molecules and microbial pathogens: evidence for the missing link in autoimmunity with rheumatoid arthritis as a disease model. Front Microbiol 2015; 5:783. [PMID: 25642219 PMCID: PMC4294210 DOI: 10.3389/fmicb.2014.00783] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2014] [Accepted: 12/21/2014] [Indexed: 12/29/2022] Open
Abstract
Rheumatoid arthritis (RA) is an autoimmune disease characterized by inflammation followed by tissue rebuilding or fibrosis. A failure by the body to regulate inflammation effectively is one of the hallmarks of RA. The interaction between the external environment and the human host plays an important role in the development of autoimmunity. In RA, the observation of anti-cyclic citrullinated peptide antibodies (ACPA) to autoantigens is well recognized. Citrullination is a post-translational modification mediated by peptidyl arginine deiminases, which exist in both mammalian and bacterial forms. Previous studies have shown how proteins expressed in the human extracellular matrix (ECM) acquire properties of damage-associated molecular patterns (DAMPs) in RA and include collagens, tenascin-C, and fibronectin (FN). ECM DAMPs can further potentiate tissue damage in RA. Recent work has shown that citrullination in RA occurs at mucosal sites, including the oral cavity and lung. Mucosal sites have been linked with bacterial infection, e.g., periodontal disease, where exogenous pathogens are implicated in the development of autoimmunity via an infectious trigger. Proteases produced at mucosal sites, both by bacteria and the human host, can induce the release of ECM DAMPs, thereby revealing neoepitopes which can be citrullinated and lead to an autoantibody response with further production of ACPA. In this perspectives article, the evidence for the interplay between the ECM and bacteria at human mucosal surfaces, which can become a focus for citrullination and the development of autoimmunity, is explored. Specific examples, with reference to collagen, fibrinogen, and FN, are discussed.
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Affiliation(s)
- Nidhi Sofat
- Institute of Infection and Immunity, St George's, University of London London, UK
| | - Robin Wait
- The Kennedy Institute of Rheumatology, Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, University of Oxford Oxford, UK
| | - Saralili D Robertson
- Institute of Infection and Immunity, St George's, University of London London, UK
| | - Deborah L Baines
- Institute of Infection and Immunity, St George's, University of London London, UK
| | - Emma H Baker
- Institute of Infection and Immunity, St George's, University of London London, UK
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21
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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22
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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23
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Badshah II, Baines DL, Dockrell ME. Erk5 is a mediator to TGFβ1-induced loss of phenotype and function in human podocytes. Front Pharmacol 2014; 5:71. [PMID: 24795631 PMCID: PMC4001011 DOI: 10.3389/fphar.2014.00071] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2013] [Accepted: 03/26/2014] [Indexed: 11/13/2022] Open
Abstract
Background: Podocytes are highly specialized cells integral to the normal functioning kidney, however, in diabetic nephropathy injury occurs leading to a compromised phenotype and podocyte dysfunction which critically produces podocyte loss with subsequent renal impairment. TGFβ1 holds a major role in the development of diabetic nephropathy. Erk5 is an atypical mitogen-activated protein (MAP) kinase involved in pathways modulating cell survival, proliferation, differentiation, and motility. Accordingly, the role of Erk5 in mediating TGFβ1-induced podocyte damage was investigated. Methods: Conditionally immortalized human podocytes were stimulated with TGFβ1 (2.5 ng/ml); inhibition of Erk5 activation was conducted with the chemical inhibitor BIX02188 (10 μM) directed to the upstream Mek5; inhibition of Alk5 was performed with SB431542 (10 μM); Ras signaling was inhibited with farnesylthiosalicylic acid (10 μM). Intracellular signaling proteins were investigated by western blotting; phenotype was explored by immunofluorescence; proliferation was assessed with a MTS assay; motility was examined with a scratch assay; barrier function was studied using electric cell-substrate impedance sensing; apoptosis was studied with annexin V-FITC flow cytometry. Results: Podocytes expressed Erk5 which was phosphorylated by TGFβ1 via Mek5, whilst not involving Ras. TGFβ1 altered podocyte phenotype by decreasing P-cadherin staining and increasing α-SMA, as well as reducing podocyte barrier function; both were prevented by inhibiting Erk5 phosphorylation with BIX02188. TGFβ1-induced podocyte proliferation was prevented by BIX02188, whereas the induced apoptosis was not. Podocyte motility was reduced by BIX02188 alone and further diminished with TGFβ1 co-incubation. Conclusion: These results describe for the first time the expression of Erk5 in podocytes and identify it as a potential target for the treatment of diabetic renal disease.
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Affiliation(s)
- Irbaz I Badshah
- South West Thames Institute for Renal Research Surrey, UK ; St. George's, University of London London, UK
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24
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Abstract
OBJECTIVE To compare the risk of fetal death on the day of childbirth, with the risk of death at other ages, and with the risks of some hazardous activities, on a common scale of risk per day. DESIGN Review of publicly available data. SETTING UK SAMPLE Data extracted from the Office of National Statistics and other sources. METHODS Data from the Office of National Statistics and other sources were used to calculate death rates at different ages expressed as rates per day of life. Death rates for different activities were also calculated as risks per day, or risks per activity, as appropriate. All risks were expressed in micromorts, the number of one in a million chances of dying. Figures on life expectancy (LE) were used to compare potential life years lost. MAIN OUTCOME MEASURES Daily, or unit of activity, risk of dying for different activities compared with the risk of dying on the day of childbirth. RESULTS The risk of dying on the day of birth (0.43 per 1000, or 430 micromorts) exceeds that of any other average day of life until the 92nd year. It is comparable with other apparently more dangerous activities, such as undergoing major surgery. For comparison, the average risk of non-natural death per day and the increased risk from smoking one cigarette or travelling 200 miles by car are all about 1 micromort. CONCLUSIONS The lifetime risk of death in childbirth is low, but is concentrated in a short period, making being born a high-risk activity. Parents considering interventions to reduce these risks should be made aware of this.
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Affiliation(s)
- K F Walker
- Maternity Department, Nottingham City Hospital, Nottingham, UK
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25
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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: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [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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26
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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27
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Garnett JP, Baker EH, Tregoning JS, Baines DL. Reduced transepithelial glucose movement in metformin‐treated airways correlates with inhibition of hyperglycemia‐induced bacterial growth. FASEB J 2013. [DOI: 10.1096/fasebj.27.1_supplement.1148.22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- James P Garnett
- Division of Biomedical Sciences, St George'sUniversity of LondonLondonUnited Kingdom
| | - Emma H Baker
- Division of Biomedical Sciences, St George'sUniversity of LondonLondonUnited Kingdom
| | - John S Tregoning
- Department of MedicineImperial College LondonLondonUnited Kingdom
| | - Deborah L Baines
- Division of Biomedical Sciences, St George'sUniversity of LondonLondonUnited Kingdom
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28
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Yang HY, Charles RP, Hummler E, Baines DL, Isseroff RR. The epithelial sodium channel mediates the directionality of galvanotaxis in human keratinocytes. J Cell Sci 2013; 126:1942-51. [PMID: 23447677 DOI: 10.1242/jcs.113225] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Cellular directional migration in an electric field (galvanotaxis) is one of the mechanisms guiding cell movement in embryogenesis and in skin epidermal repair. The epithelial sodium channel (ENaC), in addition to its function of regulating sodium transport in kidney, has recently been found to modulate cell locomotory speed. Here we tested whether ENaC has an additional function of mediating the directional migration of galvanotaxis in keratinocytes. Genetic depletion of ENaC completely blocks only galvanotaxis and does not decrease migration speed. Overexpression of ENaC is sufficient to drive galvanotaxis in otherwise unresponsive cells. Pharmacologic blockade or maintenance of the open state of ENaC also decreases or increases, respectively, galvanotaxis, suggesting that the channel open state is responsible for the response. Stable lamellipodial extensions formed at the cathodal sides of wild-type cells at the start of galvanotaxis; these were absent in the ENaC knockout keratinocytes, suggesting that ENaC mediates galvanotaxis by generating stable lamellipodia that steer cell migration. We provide evidence that ENaC is required for directional migration of keratinocytes in an electric field, supporting a role for ENaC in skin wound healing.
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Affiliation(s)
- Hsin-Ya Yang
- Department of Dermatology, University of California, Davis, CA 95616, USA
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29
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Tan CD, Smolenski RT, Harhun MI, Patel HK, Ahmed SG, Wanisch K, Yáñez-Muñoz RJ, Baines DL. AMP-activated protein kinase (AMPK)-dependent and -independent pathways regulate hypoxic inhibition of transepithelial Na+ transport across human airway epithelial cells. Br J Pharmacol 2013; 167:368-82. [PMID: 22509822 DOI: 10.1111/j.1476-5381.2012.01993.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
BACKGROUND AND PURPOSE Pulmonary transepithelial Na(+) transport is reduced by hypoxia, but in the airway the regulatory mechanisms remain unclear. We investigated the role of AMPK and ROS in the hypoxic regulation of apical amiloride-sensitive Na(+) channels and basolateral Na(+) K(+) ATPase activity. EXPERIMENTAL APPROACH H441 human airway epithelial cells were used to examine the effects of hypoxia on Na(+) transport, AMP : ATP ratio and AMPK activity. Lentiviral constructs were used to modify cellular AMPK abundance and activity; pharmacological agents were used to modify cellular ROS. KEY RESULTS AMPK was activated by exposure to 3% or 0.2% O(2) for 60 min in cells grown in submerged culture or when fluid (0.1 mL·cm(-2) ) was added to the apical surface of cells grown at the air-liquid interface. Only 0.2% O(2) activated AMPK in cells grown at the air-liquid interface. AMPK activation was associated with elevation of cellular AMP:ATP ratio and activity of the upstream kinase LKB1. Hypoxia inhibited basolateral ouabain-sensitive I(sc) (I(ouabain) ) and apical amiloride-sensitive Na(+) conductance (G(Na+) ). Modification of AMPK activity prevented the effect of hypoxia on I(ouabain) (Na(+) K(+) ATPase) but not apical G(Na+) . Scavenging of superoxide and inhibition of NADPH oxidase prevented the effect of hypoxia on apical G(Na+) (epithelial Na(+) channels). CONCLUSIONS AND IMPLICATIONS Hypoxia activates AMPK-dependent and -independent pathways in airway epithelial cells. Importantly, these pathways differentially regulate apical Na(+) channels and basolateral Na(+) K(+) ATPase activity to decrease transepithelial Na(+) transport. Luminal fluid potentiated the effect of hypoxia and activated AMPK, which could have important consequences in lung disease conditions.
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Affiliation(s)
- C D Tan
- Pharmacology and Cell Physiology Research Group, Division of Biomedical Sciences, St George's University of London, Cranmer Terrace, London, UK
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30
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Althaus M, Urness KD, Clauss WG, Baines DL, Fronius M. The gasotransmitter hydrogen sulphide decreases Na⁺ transport across pulmonary epithelial cells. Br J Pharmacol 2012; 166:1946-63. [PMID: 22352810 DOI: 10.1111/j.1476-5381.2012.01909.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
BACKGROUND AND PURPOSE The transepithelial absorption of Na(+) in the lungs is crucial for the maintenance of the volume and composition of epithelial lining fluid. The regulation of Na(+) transport is essential, because hypo- or hyperabsorption of Na(+) is associated with lung diseases such as pulmonary oedema or cystic fibrosis. This study investigated the effects of the gaseous signalling molecule hydrogen sulphide (H(2) S) on Na(+) absorption across pulmonary epithelial cells. EXPERIMENTAL APPROACH Ion transport processes were electrophysiologically assessed in Ussing chambers on H441 cells grown on permeable supports at air/liquid interface and on native tracheal preparations of pigs and mice. The effects of H(2)S were further investigated on Na(+) channels expressed in Xenopus oocytes and Na(+) /K(+)-ATPase activity in vitro. Membrane abundance of Na(+) /K(+)-ATPase was determined by surface biotinylation and Western blot. Cellular ATP concentrations were measured colorimetrically, and cytosolic Ca(2+) concentrations were measured with Fura-2. KEY RESULTS H(2)S rapidly and reversibly inhibited Na(+) transport in all the models employed. H(2)S had no effect on Na(+) channels, whereas it decreased Na(+) /K(+)-ATPase currents. H(2)S did not affect the membrane abundance of Na(+) /K(+)-ATPase, its metabolic or calcium-dependent regulation, or its direct activity. However, H(2)S inhibited basolateral calcium-dependent K(+) channels, which consequently decreased Na(+) absorption by H441 monolayers. CONCLUSIONS AND IMPLICATIONS H(2) S impairs pulmonary transepithelial Na(+) absorption, mainly by inhibiting basolateral Ca(2+)-dependent K(+) channels. These data suggest that the H(2)S signalling system might represent a novel pharmacological target for modifying pulmonary transepithelial Na(+) transport.
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Affiliation(s)
- M Althaus
- Institute of Animal Physiology, Justus-Liebig University of Giessen, Giessen, Germany.
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31
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Abstract
For over 50 years, glucose has been recognised to cross the lung epithelial barrier and be transported by lung epithelial cells. However, until recently, research into these processes focused on their effects on lung liquid volume. Here, we consider a newly identified role for pulmonary glucose transport in maintaining low airway surface liquid (ASL) glucose concentrations and propose that this contributes to lung defence against infection. Glucose diffuses into ASL via paracellular pathways at a rate determined by paracellular permeability and the transepithelial glucose gradient. Glucose is removed from ASL in proximal airways via facilitative glucose transporters, down a concentration gradient generated by intracellular glucose metabolism. In the distal lung, glucose transport via sodium-coupled glucose transporters predominates. These processes vary between species but universally maintain ASL glucose at 3-20-fold lower concentrations than plasma. ASL glucose concentrations are increased in respiratory disease and by hyperglycaemia. Elevated ASL glucose in intensive care patients was associated with increased Staphylococcus aureus infection. Diabetic patients with and without chronic lung disease are at increased risk of respiratory infection. Understanding of mechanisms underlying lung glucose homeostasis could identify new therapeutic targets for control of ASL glucose and prevention and treatment of lung infection.
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Affiliation(s)
- James P Garnett
- Division of Biomedical Sciences St George's, University of London, London, UK
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32
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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. J Immunol 2012; 189:373-80. [PMID: 22623330 DOI: 10.4049/jimmunol.1200718] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [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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33
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Althaus M, Urness KD, Clauss W, Baines DL, Fronius M. The gasotransmitter hydrogen sulphide decreases Na
+
transport across lung epithelial cells. FASEB J 2012. [DOI: 10.1096/fasebj.26.1_supplement.696.6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Mike Althaus
- Institute of Animal PhysiologyJustus-Liebig University of GiessenGiessenGermany
| | | | - Wolfgang Clauss
- Institute of Animal PhysiologyJustus-Liebig University of GiessenGiessenGermany
| | - Deborah L Baines
- Division of Biomedical SciencesSt George's University of LondonLondonUnited Kingdom
| | - Martin Fronius
- Institute of Animal PhysiologyJustus-Liebig University of GiessenGiessenGermany
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34
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Garnett JP, Naik S, Baker E, Baines DL. Metformin restricts the basolateral glucose dependent growth of apical
Staphylococcus aureus
in airway epithelia‐bacteria co‐cultures. FASEB J 2012. [DOI: 10.1096/fasebj.26.1_supplement.885.22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- James Peter Garnett
- Division of Biomedical SciencesSt George's, University of LondonLondonUnited Kingdom
| | - Sonam Naik
- Division of Biomedical SciencesSt George's, University of LondonLondonUnited Kingdom
| | - Emma Baker
- Division of Biomedical SciencesSt George's, University of LondonLondonUnited Kingdom
| | - Deborah L Baines
- Division of Biomedical SciencesSt George's, University of LondonLondonUnited Kingdom
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35
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Baines DL, Albert AP, Hazell MJ, Gambling L, Woollhead AM, Dockrell MEC. Lipopolysaccharide modifies amiloride-sensitive Na+ transport processes across human airway cells: role of mitogen-activated protein kinases ERK 1/2 and 5. Pflugers Arch 2009; 459:451-63. [PMID: 19823867 PMCID: PMC2810363 DOI: 10.1007/s00424-009-0717-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2009] [Accepted: 08/14/2009] [Indexed: 02/08/2023]
Abstract
Bacterial lipopolysaccharides (LPS) are potent inducers of proinflammatory signaling pathways via the activation of nuclear factor-kappa B (NF-κB) and mitogen-activated protein kinase (MAPK), causing changes in the processes that control lung fluid homeostasis and contributing to the pathogenesis of lung disease. In human H441 airway epithelial cells, incubation of cells with 15 µg ml−1 LPS caused a significant reduction in amiloride-sensitive Isc from 15 ± 2 to 8 ± 2 µA cm−2 (p = 0.01, n = 13) and a shift in IC50 amiloride of currents from 6.8 × 10−7 to 6.4 × 10−6 M. This effect was associated with a decrease in the activity of 5 pS, highly Na+ selective, amiloride-sensitive <1 µM channels (HSC) and an increase in the activity of ∼18 pS, nonselective, amiloride-sensitive >10 µM cation channels (NSC) in the apical membrane. LPS decreased αENaC mRNA and protein abundance, inferring that LPS inhibited αENaC gene expression. This correlated with the decrease in HSC activity, indicating that these channels, but not NSCs, were comprised of at least αENaC protein. LPS increased NF-κB DNA binding activity and phosphorylation of extracellular signal-related kinase (ERK)1/2, but decreased phosphorylation of ERK5 in H441 cells. Pretreatment of monolayers with PD98059 (20 µM) inhibited ERK1/2 phosphorylation, promoted phosphorylation of ERK5, increased αENaC protein abundance, and reversed the effect of LPS on Isc and the shift in amiloride sensitivity. Inhibitors of NF-κB activation were without effect. Taken together, our data indicate that LPS acts via ERK signaling pathways to decrease αENaC transcription, reducing HSC/ENaC channel abundance, activity, and transepithelial Na+ transport in H441 airway epithelial cells.
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Affiliation(s)
- D L Baines
- St. George's, University of London, Tooting, London SW17 0RE, UK.
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36
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Kalsi KK, Baker EH, Fraser O, Chung YL, Mace OJ, Tarelli E, Philips BJ, Baines DL. Glucose homeostasis across human airway epithelial cell monolayers: role of diffusion, transport and metabolism. Pflugers Arch 2008; 457:1061-70. [PMID: 18781323 DOI: 10.1007/s00424-008-0576-4] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2008] [Accepted: 08/09/2008] [Indexed: 12/20/2022]
Abstract
Glucose in airway surface liquid (ASL) is maintained at low concentrations compared to blood glucose. Using radiolabelled [(3)H]-D: -glucose and [(14)C]-L: -glucose, detection of D: - and L: -glucose by high-performance liquid chromatography and metabolites by nuclear magnetic resonance, we found that glucose applied to the basolateral side of H441 human airway epithelial cell monolayers at a physiological concentration (5 mM) crossed to the apical side by paracellular diffusion. Transepithelial resistance of the monolayer was inversely correlated with paracellular diffusion. Appearance of glucose in the apical compartment was reduced by uptake of glucose into the cell by basolateral and apical phloretin-sensitive GLUT transporters. Glucose taken up into the cell was metabolised to lactate which was then released, at least in part, across the apical membrane. We suggest that glucose transport through GLUT transporters and its subsequent metabolism in lung epithelial cells help to maintain low glucose concentrations in human ASL which is important for protecting the lung against infection.
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Affiliation(s)
- Kameljit K Kalsi
- Centre for Ion Channel and Cell Signalling, St George's, University of London, Cranmer Terrace, UK
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37
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Albert AP, Woollhead AM, Mace OJ, Baines DL. AICAR decreases the activity of two distinct amiloride-sensitive Na+-permeable channels in H441 human lung epithelial cell monolayers. Am J Physiol Lung Cell Mol Physiol 2008; 295:L837-48. [PMID: 18723760 PMCID: PMC2584878 DOI: 10.1152/ajplung.90353.2008] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Transepithelial transport of Na+ across the lung epithelium via amiloride-sensitive Na+ channels (ENaC) regulates fluid volume in the lung lumen. Activators of AMP-activated protein kinase (AMPK), the adenosine monophosphate mimetic AICAR, and the biguanide metformin decreased amiloride-sensitive apical Na+ conductance (GNa+) in human H441 airway epithelial cell monolayers. Cell-attached patch-clamp recordings identified two distinct constitutively active cation channels in the apical membrane that were likely to contribute to GNa+: a 5-pS highly Na+ selective ENaC-like channel (HSC) and an 18-pS nonselective cation channel (NSC). Substituting NaCl with NMDG-Cl in the patch pipette solution shifted the reversal potentials of HSC and NSC, respectively, from +23 mV to −38 mV and 0 mV to −35 mV. Amiloride at 1 μM inhibited HSC activity and 56% of short-circuit current (Isc), whereas 10 μM amiloride partially reduced NSC activity and inhibited a further 30% of Isc. Neither conductance was associated with CNG channels as there was no effect of 10 μM pimoside on Isc, HSC, or NSC activity, and 8-bromo-cGMP (0.3–0.1 mM) did not induce or increase HSC or NSC activity. Pretreatment of H441 monolayers with 2 mM AICAR inhibited HSC/NSC activity by 90%, and this effect was reversed by the AMPK inhibitor Compound C. All three ENaC proteins were identified in the apical membrane of H441 monolayers, but no change in their abundance was detected after treatment with AICAR. In conclusion, activation of AMPK with AICAR in H441 cell monolayers is associated with inhibition of two distinct amiloride-sensitive Na+-permeable channels by a mechanism that likely reduces channel open probability.
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Affiliation(s)
- A P Albert
- Centre for Ion Channels and Cell Signalling, Division of Basic Medical Sciences, St. George's, University of London, London, UK
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38
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Mace OJ, Woollhead AM, Baines DL. AICAR activates AMPK and alters PIP2 association with the epithelial sodium channel ENaC to inhibit Na+ transport in H441 lung epithelial cells. J Physiol 2008; 586:4541-57. [PMID: 18669532 DOI: 10.1113/jphysiol.2008.158253] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Changes in amiloride-sensitive epithelial Na(+) channel (ENaC) activity (NP(o)) in the lung lead to pathologies associated with dysregulation of lung fluid balance. UTP activation of purinergic receptors and hydrolysis of PIP(2) via activation of phospholipase C (PLC) or AICAR activation of AMP-activated protein kinase (AMPK) inhibited amiloride-sensitive Na(+) transport across human H441 epithelial cell monolayers. Neither treatment altered alpha, beta or gamma ENaC subunit abundance (N) in the apical membrane indicating that the mechanism of inhibition was via a change in channel open state probability (P(o)). We found that UTP depleted PIP(2) abundance in the apical membrane whilst activation of AMPK prevented the binding of beta and gamma ENaC subunits to PIP(2.) The association of PIP(2) with the ENaC subunits is required to maintain channel activity via P(o). Thus, these data show for the first time that AICAR activation of AMPK inhibits Na(+) transport via a mechanism that perturbs the PIP(2)-ENaC channel interaction to alter P(o). In addition, we show that dissociation of PIP(2) from ENaC together with activation of AMPK further reduced Na(+) transport by a secondary effect that correlated with ENaC subunit internalization. Thus, when PIP(2)-ENaC subunit interactions were compromised, ENaC protein retrieval was initiated, indicating that AMPK can modulate ENaC P(o) and N.
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Affiliation(s)
- Oliver J Mace
- Division of Basic Medical Sciences, St George's University of London, Cranmer Terrace, London SW17 0RE, UK.
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39
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Greenwood IA, Yeung SYM, Hettiarachi S, Andersson M, Baines DL. KCNQ-encoded channels regulate Na+ transport across H441 lung epithelial cells. Pflugers Arch 2008; 457:785-94. [PMID: 18663467 DOI: 10.1007/s00424-008-0557-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2008] [Revised: 07/09/2008] [Accepted: 07/09/2008] [Indexed: 12/11/2022]
Abstract
H441 cells are a model of absorptive airway epithelia that are characterised by a pronounced apical Na+ flux through amiloride-sensitive Na+ channels. The flux of Na+ is intimately linked to Na+ handling by the cell as well as the membrane potential across the apical membrane. As KCNQ-encoded K+ channels influence chloride secretion in gastrointestinal epithelia, the goal of the present study was to ascertain the expression of KCNQ genes in H441 cells and determine the functional role of the expression products. Message for KCNQ3 and KCNQ5 was detected by RT-polymerase chain reaction and the translated proteins were observed by immunocytochemistry. Ussing experiments showed that the pan-KCNQ channel blocker XE991, but not KCNQ1 selective blockers, reduced the short circuit current and the amiloride-sensitive component. These data show for the first time that potassium channels encoded by KCNQ3 or KCNQ5 are crucial determinants of epithelial Na+ flux.
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Affiliation(s)
- I A Greenwood
- Division of Basic Medical Sciences, St. George's, University of London, London, SW17 0RE, UK
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40
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Kalsi KK, Fraser O, Chung Y, Tarelli E, Philips B, Baker E, Baines DL. Transepithelial glucose transport and metabolism in H441 human airway epithelial cells. FASEB J 2008. [DOI: 10.1096/fasebj.22.1_supplement.764.5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | - Owen Fraser
- Basic Medical SciencesSt George's, University of LondonLondonUnited Kingdom
| | - Yuen‐Li Chung
- Basic Medical SciencesSt George's, University of LondonLondonUnited Kingdom
| | - Edward Tarelli
- Basic Medical SciencesSt George's, University of LondonLondonUnited Kingdom
| | - Barbara Philips
- Basic Medical SciencesSt George's, University of LondonLondonUnited Kingdom
| | - Emma Baker
- Basic Medical SciencesSt George's, University of LondonLondonUnited Kingdom
| | - Deborah L Baines
- Basic Medical SciencesSt George's, University of LondonLondonUnited Kingdom
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41
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Baines DL, Albert AP, Woollhead AM. Lipopolysaccharides modify amiloride‐sensitive Na
+
transport processes across H441 lung epithelial cells. FASEB J 2008. [DOI: 10.1096/fasebj.22.1_supplement.934.2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Deborah L Baines
- Basic Medical SciencesSt. George'sUniversity of LondonLondonUnited Kingdom
| | - Anthony P Albert
- Basic Medical SciencesSt. George'sUniversity of LondonLondonUnited Kingdom
| | - Alison M Woollhead
- School of Pharmacy and Biomolecular SciencesUniversity of BrightonBrightonUnited Kingdom
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42
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Mace OJ, Baines DL. Regulation of Na
+
transport in H441 cells by AMPK and PIP
2. FASEB J 2008. [DOI: 10.1096/fasebj.22.1_supplement.1215.3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Oliver John Mace
- Basic Medical SciencesSt. George'sUniversity of LondonLondonUnited Kingdom
| | - Deborah L Baines
- Basic Medical SciencesSt. George'sUniversity of LondonLondonUnited Kingdom
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43
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Kalsi KK, Baker EH, Medina RA, Rice S, Wood DM, Ratoff JC, Philips BJ, Baines DL. Apical and basolateral localisation of GLUT2 transporters in human lung epithelial cells. Pflugers Arch 2008; 456:991-1003. [PMID: 18239936 PMCID: PMC2480509 DOI: 10.1007/s00424-008-0459-8] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2007] [Revised: 01/11/2008] [Accepted: 01/15/2008] [Indexed: 12/15/2022]
Abstract
Glucose concentrations of normal human airway surface liquid are ~12.5 times lower than blood glucose concentrations indicating that glucose uptake by epithelial cells may play a role in maintaining lung glucose homeostasis. We have therefore investigated potential glucose uptake mechanisms in non-polarised and polarised H441 human airway epithelial cells and bronchial biopsies. We detected mRNA and protein for glucose transporter type 2 (GLUT2) and glucose transporter type 4 (GLUT4) in non-polarised cells but GLUT4 was not detected in the plasma membrane. In polarised cells, GLUT2 protein was detected in both apical and basolateral membranes. Furthermore, GLUT2 protein was localised to epithelial cells of human bronchial mucosa biopsies. In non-polarised H441 cells, uptake of d-glucose and deoxyglucose was similar. Uptake of both was inhibited by phloretin indicating that glucose uptake was via GLUT-mediated transport. Phloretin-sensitive transport remained the predominant route for glucose uptake across apical and basolateral membranes of polarised cells and was maximal at 5–10 mM glucose. We could not conclusively demonstrate sodium/glucose transporter-mediated transport in non-polarised or polarised cells. Our study provides the first evidence that glucose transport in human airway epithelial cells in vitro and in vivo utilises GLUT2 transporters. We speculate that these transporters could contribute to glucose uptake/homeostasis in the human airway.
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Affiliation(s)
- Kameljit K Kalsi
- Centre for Ion Channel and Cell Signalling, Division of Basic Medical Sciences, St George's, University of London, Cranmer Terrace, London, SW17 0RE, UK
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44
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Diwakar R, Pearson AL, Colville-Nash P, Baines DL, Dockrell MEC. Role played by disabled-2 in albumin induced MAP Kinase signalling. Biochem Biophys Res Commun 2007; 366:675-80. [PMID: 18070591 DOI: 10.1016/j.bbrc.2007.11.171] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2007] [Accepted: 11/27/2007] [Indexed: 10/22/2022]
Abstract
Albumin has been shown to activate the mitogen activated protein kinase (MAPK) pathway in proximal tubular cells (PTECs) of the kidney. Megalin, the putative receptor for albumin has potential signalling properties. However, the mechanisms by which megalin signals are unclear. The adaptor phosphoprotein Disabled-2 (Dab2) is known to interact with the cytoplasmic tail of megalin and may be involved in albumin-mediated MAPK signalling. In this study, we investigated the role of Dab2 in albumin-mediated MAPK signalling and further studied the role of Dab2 in albumin-induced TGFbeta-1 secretion, a MAPK dependent event. We used RNA interference to knockdown Dab2 protein abundance in HKC-8 cells a model of human PTECs. Albumin activated ERK1,2 and Elk-1 in a MEK-1 dependent manner and resulted in secretion of TGFbeta-1. In the absence of albumin, knockdown of Dab2 resulted in a trend towards increase in pERK1,2 consistent with its putative role as an inhibitor of cell proliferation. However albumin-induced ERK1,2 activation was completely abolished by Dab2 knockdown. Dab2 knockdown did not however result in inhibition of albumin-induced TGFbeta-1 secretion. These results suggest that Dab2 is a ligand dependent bi-directional regulator of ERK1,2 activity by demonstrating that in addition to its more traditional role as an inhibitor of ERK1,2 it may also activate ERK1,2.
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Affiliation(s)
- Ramaswamy Diwakar
- South West Thames Institute for Renal Research, St. Helier Hospital, Wrythe Lane, Carshalton, Surrey SM5 1AA, UK
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45
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Woollhead AM, Sivagnanasundaram J, Kalsi KK, Pucovsky V, Pellatt LJ, Scott JW, Mustard KJ, Hardie DG, Baines DL. Pharmacological activators of AMP-activated protein kinase have different effects on Na+ transport processes across human lung epithelial cells. Br J Pharmacol 2007; 151:1204-15. [PMID: 17603555 PMCID: PMC2189835 DOI: 10.1038/sj.bjp.0707343] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
BACKGROUND AND PURPOSE AMP-activated protein kinase (AMPK) is activated by metformin, phenformin, and the AMP mimetic, 5-aminoimidazole-4-carboxamide-1-beta-D-ribofuranoside (AICAR). We have completed an extensive study of the pharmacological effects of these drugs on AMPK activation, adenine nucleotide concentration, transepithelial amiloride-sensitive (I(amiloride)) and ouabain-sensitive basolateral (I(ouabain)) short circuit current in H441 lung epithelial cells. EXPERIMENTAL APPROACH H441 cells were grown on permeable filters at air interface. I(amiloride), I(ouabain) and transepithelial resistance were measured in Ussing chambers. AMPK activity was measured as the amount of radiolabelled phosphate transferred to the SAMS peptide. Adenine nucleotide concentration was analysed by reverse phase HPLC and NAD(P)H autofluorescence was measured using confocal microscopy. KEY RESULTS Phenformin, AICAR and metformin increased AMPK (alpha1) activity and decreased I(amiloride). The AMPK inhibitor Compound C prevented the action of metformin and AICAR but not phenformin. Phenformin and AICAR decreased I(ouabain) across H441 monolayers and decreased monolayer resistance. The decrease in I(amiloride) was closely related to I(ouabain) with phenformin, but not in AICAR treated monolayers. Metformin and phenformin increased the cellular AMP:ATP ratio but only phenformin and AICAR decreased cellular ATP. CONCLUSIONS AND IMPLICATIONS Activation of alpha1-AMPK is associated with inhibition of apical amiloride-sensitive Na(+) channels (ENaC), which has important implications for the clinical use of metformin. Additional pharmacological effects evoked by AICAR and phenformin on I(ouabain), with potential secondary effects on apical Na+ conductance, ENaC activity and monolayer resistance, have important consequences for their use as pharmacological activators of AMPK in cell systems where Na+K+ATPase is an important component.
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Affiliation(s)
- A M Woollhead
- Centre for Ion Channels and Cell Signalling, Div. of Basic Medical Sciences, St George's, University of London London, UK
| | - J Sivagnanasundaram
- Centre for Ion Channels and Cell Signalling, Div. of Basic Medical Sciences, St George's, University of London London, UK
| | - K K Kalsi
- Centre for Ion Channels and Cell Signalling, Div. of Basic Medical Sciences, St George's, University of London London, UK
| | - V Pucovsky
- Centre for Ion Channels and Cell Signalling, Div. of Basic Medical Sciences, St George's, University of London London, UK
| | - L J Pellatt
- Centre for Ion Channels and Cell Signalling, Div. of Basic Medical Sciences, St George's, University of London London, UK
| | - J W Scott
- Division of Molecular Physiology, School of Life Sciences, University of Dundee Dundee, UK
| | - K J Mustard
- Division of Molecular Physiology, School of Life Sciences, University of Dundee Dundee, UK
| | - D G Hardie
- Division of Molecular Physiology, School of Life Sciences, University of Dundee Dundee, UK
| | - D L Baines
- Centre for Ion Channels and Cell Signalling, Div. of Basic Medical Sciences, St George's, University of London London, UK
- Author for correspondence:
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46
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Baker EH, Clark N, Brennan AL, Fisher DA, Gyi KM, Hodson ME, Philips BJ, Baines DL, Wood DM. Hyperglycemia and cystic fibrosis alter respiratory fluid glucose concentrations estimated by breath condensate analysis. J Appl Physiol (1985) 2007; 102:1969-75. [PMID: 17303703 DOI: 10.1152/japplphysiol.01425.2006] [Citation(s) in RCA: 128] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
In animals, glucose concentrations are 3–20 times lower in lung lining fluid than in plasma. In humans, glucose concentrations are normally low (<1 mmol/l) in nasal and bronchial fluid, but they are elevated by inflammation or hyperglycemia. Furthermore, elevated bronchial glucose is associated with increased respiratory infection in intensive care patients. Our aims were to estimate normal glucose concentrations in fluid from distal human lung sampled noninvasively and to determine effects of hyperglycemia and lung disease on lung glucose concentrations. Respiratory fluid was sampled as exhaled breath condensate, and glucose was measured by chromatography with pulsed amperometric detection. Dilution corrections, based on conductivity, were applied to estimate respiratory fluid glucose concentrations (breath glucose). We found that breath glucose in healthy volunteers was 0.40 mmol/l (SD 0.24), reproducible, and unaffected by changes in salivary glucose. Breath-to-blood glucose ratio (BBGR) was 0.08 (SD 0.05). Breath glucose increased during experimental hyperglycemia ( P < 0.05) and was elevated in diabetic patients without lung disease [1.20 mmol/l (SD 0.69)] in proportion to hyperglycemia [BBGR 0.09 (SD 0.06)]. Breath glucose was elevated more than expected for blood glucose in cystic fibrosis patients [breath 2.04 mmol/l (SD 1.14), BBGR 0.29 (SD 0.17)] and in cystic fibrosis-related diabetes [breath 4.00 mmol/l (SD 2.07), BBGR 0.54 (0.28); P < 0.0001]. These data indicate that 1) this method makes a biologically plausible estimate of respiratory fluid glucose concentration, 2) respiratory fluid glucose concentrations are elevated by hyperglycemia and lung disease, and 3) effects of hyperglycemia and lung disease can be distinguished using the BBGR. This method will support future in vivo investigation of the cause and effect of elevated respiratory fluid glucose in human lung disease.
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Affiliation(s)
- Emma H Baker
- Cardiac and Vascular Sciences (Respiratory), St. George's, University of London, Cranmer Terrace, London SW17 0RE, UK.
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47
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Kalsi KK, Medina RA, Heap GA, Baker EH, Philips BJ, Baines DL. Glucose transport in lung airway epithelial cells. FASEB J 2007. [DOI: 10.1096/fasebj.21.5.a543-d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Kameljit Kaur Kalsi
- Basic Medical Sciences, St GeorgesUniversity of LondonCranmer TerraceLondonSW17 0REUnited Kingdom
| | - Rudulfo A Medina
- Basic Medical Sciences, St GeorgesUniversity of LondonCranmer TerraceLondonSW17 0REUnited Kingdom
| | - Graham A Heap
- Basic Medical Sciences, St GeorgesUniversity of LondonCranmer TerraceLondonSW17 0REUnited Kingdom
| | - Emma H Baker
- Basic Medical Sciences, St GeorgesUniversity of LondonCranmer TerraceLondonSW17 0REUnited Kingdom
| | - Barbara J Philips
- Basic Medical Sciences, St GeorgesUniversity of LondonCranmer TerraceLondonSW17 0REUnited Kingdom
| | - Deborah L Baines
- Basic Medical Sciences, St GeorgesUniversity of LondonCranmer TerraceLondonSW17 0REUnited Kingdom
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48
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Brennan AL, Gyi KM, Wood DM, Johnson J, Holliman R, Baines DL, Philips BJ, Geddes DM, Hodson ME, Baker EH. Airway glucose concentrations and effect on growth of respiratory pathogens in cystic fibrosis. J Cyst Fibros 2007; 6:101-9. [PMID: 16844431 DOI: 10.1016/j.jcf.2006.03.009] [Citation(s) in RCA: 131] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2006] [Revised: 03/24/2006] [Accepted: 03/31/2006] [Indexed: 10/24/2022]
Abstract
BACKGROUND Pulmonary decline accelerates in cystic fibrosis-related diabetes (CFRD) proportional to severity of glucose intolerance, but mechanisms are unclear. In people without CF, airway glucose (AG) concentrations are elevated when blood glucose (BG)> or =8 mmol L(-1) (airway threshold), and are associated with acquisition of respiratory infection. METHODS To determine the relationship between BG and AG, 40 CF patients underwent paired BG and AG (nasal) measurements. Daily time with BG>airway threshold was compared in 10 CFRD, 10 CF patients with normal glucose tolerance (CF-NGT) and 10 healthy volunteers by continuous BG monitoring. The effect of glucose at airway concentrations on bacterial growth was determined in vitro by optical densitometry. RESULTS AG was present more frequently (85%-vs.-19%, p<0.0001) and at higher concentrations (0.5-3 mmol L(-1)-vs.-0.5-1 mmol L(-1), p<0.0001) when BG was > or =8 mmol L(-1)-vs.-<8 mmol L(-1). Daily time with BG> or =8 mmol L(-1) was CFRD (49+/-25%), CF-NGT (6+/-5%), healthy volunteers (1+/-3%), p<0.0001. Staphylococcus aureus growth increased at > or =0.5 mmol L(-1) (p=0.006) and Pseudomonas aeruginosa growth above 1-4 mmol L(-1) glucose (p=0.039). CONCLUSIONS BG> or =8 mmol L(-1) predicted elevated AG concentrations in CF, at least in nasal secretions. CFRD patients spent approximately 50% day with BG>airway threshold, implying persistently elevated AG concentrations. Further studies are required to determine whether elevated airway glucose concentrations contribute to accelerated pulmonary decline in CFRD.
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Affiliation(s)
- Amanda L Brennan
- Glucose and Pulmonary Infection Group, St George's, University of London, Room 66, Ground Floor Jenner Wing, Cardiac and Vascular Sciences (Respiratory), Cranmer Terrace, SW17 0RE, London, United Kingdom
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49
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Abstract
Pathophysiological stress from acute illness causes metabolic disturbance, including altered hepatic glucose metabolism, increased peripheral insulin resistance and hyperglycaemia. Acute hyperglycaemia is associated with increased morbidity and mortality in patients in intensive care units and patients with acute respiratory disease. The present review will consider mechanisms underlying this association. In normal lungs the glucose concentration of airway secretions is approximately 10-fold lower than that of plasma. Low airway glucose concentrations are maintained against a concentration gradient by active glucose transport. Airway glucose concentrations become elevated if normal homeostasis is disrupted by a rise in blood glucose concentrations or inflammation of the airway epithelium. Elevated airway glucose concentrations are associated with and precede increased isolation of respiratory pathogens, particularly methicillin-resistant Staphylococcus aureus, from bronchial aspirates of patients intubated on intensive care. Markers of elevated airway glucose are associated with similar patterns of respiratory infection in patients admitted with acute exacerbations of chronic obstructive pulmonary disease. Glucose at airway concentrations stimulates the growth of respiratory pathogens, over and above the effect of other nutrients. Elevated airway glucose concentrations may also worsen respiratory disease by promoting local inflammation. Hyperglycaemia may thus promote pulmonary infection, at least in part, by an effect on airway glucose concentrations. Therapeutic options, including systemic control of blood glucose and local manipulation of airway glucose homeostasis, will be considered.
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Affiliation(s)
- Emma H Baker
- Glucose and Pulmonary Infection Group, Cardiac and Vascular Sciences (Respiratory), St George's, University of London, Cranmer Terrace, London SW17 0RE, UK.
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50
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Woollhead AM, Scott JW, Albert AP, Kalsi KK, Hardie DG, Baines DL. Phenformin and AICAR decrease transepithelial Na+ transport across human H441 lung epithelial cells by different mechanisms. FASEB J 2007. [DOI: 10.1096/fasebj.21.6.a954-b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Alison M Woollhead
- Basic Medical SciencesSt. George’sUniversity of LondonCranmer TerraceLondonSW17 0REUnited Kingdom
| | - John W Scott
- Division of Molecular PhysiologyUniversity of DundeeWellcome Trust BiocentreDundeeDD1 5EHUnited Kingdom
| | - Anthony P Albert
- Basic Medical SciencesSt. George’sUniversity of LondonCranmer TerraceLondonSW17 0REUnited Kingdom
| | - Kameljit K Kalsi
- Basic Medical SciencesSt. George’sUniversity of LondonCranmer TerraceLondonSW17 0REUnited Kingdom
| | - D Grahame Hardie
- Division of Molecular PhysiologyUniversity of DundeeWellcome Trust BiocentreDundeeDD1 5EHUnited Kingdom
| | - Deborah L Baines
- Basic Medical SciencesSt. George’sUniversity of LondonCranmer TerraceLondonSW17 0REUnited Kingdom
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