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ABSTRACT: Chronic lung disease remains the major cause of morbidity and mortality of cystic fibrosis (CF) patients. Cftr mutant mice developed severe intestinal obstruction, but did not exhibit the characteristic CF ion transport defects (i.e. deficient cAMP-dependent Cl(-) secretion and increased Na(+) absorption) in the lower airways, and failed to develop CF-like lung disease. These observations led to the generation of transgenic mice with airway-specific overexpression of the epithelial Na(+) channel (ENaC) as an alternative approach to mimic CF ion transport pathophysiology in the lung. Studies of the phenotype of βENaC-transgenic mice demonstrated that increased airway Na(+) absorption causes airway surface liquid (ASL) depletion, reduced mucus transport and a spontaneous CF-like lung disease with airway mucus obstruction and chronic airway inflammation. Here, we summarize approaches that can be applied for studies of the complex in vivo pathogenesis and preclinical evaluation of novel therapeutic strategies in this model of CF lung disease.
Journal of cystic fibrosis: official journal of the European Cystic Fibrosis Society 06/2011; 10 Suppl 2:S172-82. · 3.19 Impact Factor
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Veronica Marcos, Zhe Zhou,
Ali Önder Yildirim,
Alexander Bohla,
Andreas Hector,
Ljubomir Vitkov,
Eva-Maria Wiedenbauer,
Wolf Dietrich Krautgartner,
Walter Stoiber,
Bernd H Belohradsky,
Nikolaus Rieber,
Michael Kormann,
Barbara Koller,
Adelbert Roscher,
Dirk Roos,
Matthias Griese,
Oliver Eickelberg,
Gerd Döring,
Marcus A Mall,
Dominik Hartl
Nature medicine 01/2011; 17(7):899. · 27.14 Impact Factor
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Andreas Hector,
Michael S D Kormann,
Ines Mack,
Philipp Latzin,
Carmen Casaulta,
Elisabeth Kieninger, Zhe Zhou,
Ali Ö Yildirim,
Alexander Bohla,
Nikolaus Rieber,
Matthias Kappler,
Barbara Koller,
Ernst Eber,
Olaf Eickmeier,
Stefan Zielen,
Oliver Eickelberg,
Matthias Griese,
Marcus A Mall,
Dominik Hartl
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ABSTRACT: The chitinase-like protein YKL-40 was found to be increased in patients with severe asthma and chronic obstructive pulmonary disease (COPD), two disease conditions featuring neutrophilic infiltrates. Based on these studies and a previous report indicating that neutrophils secrete YKL-40, we hypothesized that YKL-40 plays a key role in cystic fibrosis (CF) lung disease, a prototypic neutrophilic disease. The aim of this study was (i) to analyze YKL-40 levels in human and murine CF lung disease and (ii) to investigate whether YKL-40 single-nucleotide polymorphisms (SNPs) modulate CF lung disease severity. YKL-40 protein levels were quantified in serum and sputum supernatants from CF patients and control individuals. Levels of the murine homologue BRP-39 were analyzed in airway fluids from CF-like βENaC-Tg mice. YKL-40SNPs were analyzed in CF patients. YKL-40 levels were increased in sputum supernatants and in serum from CF patients compared to healthy control individuals. Within CF patients, YKL-40 levels were higher in sputum than in serum. BRP-39 levels were increased in airways fluids from βENaC-Tg mice compared to wild-type littermates. In both CF patients and βENaC-Tg mice, YKL-40/BRP-39 airway levels correlated with the severity of pulmonary obstruction. Two YKL-40 SNPs (rs871799 and rs880633) were found to modulate age-adjusted lung function in CF patients. YKL-40/BRP-39 levelsare increased in human and murine CF airway fluids, correlate with pulmonary function and modulate CF lung disease severity genetically. These findings suggest YKL-40 as a potential biomarker in CF lung disease.
PLoS ONE 01/2011; 6(9):e24399. · 4.09 Impact Factor
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Veronica Marcos, Zhe Zhou,
Ali Onder Yildirim,
Alexander Bohla,
Andreas Hector,
Ljubomir Vitkov,
Eva-Maria Wiedenbauer,
Wolf Dietrich Krautgartner,
Walter Stoiber,
Bernd H Belohradsky,
Nikolaus Rieber,
Michael Kormann,
Barbara Koller,
Adelbert Roscher,
Dirk Roos,
Matthias Griese,
Oliver Eickelberg,
Gerd Döring,
Marcus A Mall,
Dominik Hartl
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ABSTRACT: Upon activation, neutrophils release DNA fibers decorated with antimicrobial proteins, forming neutrophil extracellular traps (NETs). Although NETs are bactericidal and contribute to innate host defense, excessive NET formation has been linked to the pathogenesis of autoinflammatory diseases. However, the mechanisms regulating NET formation, particularly during chronic inflammation, are poorly understood. Here we show that the G protein-coupled receptor (GPCR) CXCR2 mediates NET formation. Downstream analyses showed that CXCR2-mediated NET formation was independent of NADPH oxidase and involved Src family kinases. We show the pathophysiological relevance of this mechanism in cystic fibrosis lung disease, characterized by chronic neutrophilic inflammation. We found abundant NETs in airway fluids of individuals with cystic fibrosis and mouse cystic fibrosis lung disease, and NET amounts correlated with impaired obstructive lung function. Pulmonary blockade of CXCR2 by intra-airway delivery of small-molecule antagonists inhibited NET formation and improved lung function in vivo without affecting neutrophil recruitment, proteolytic activity or antibacterial host defense. These studies establish CXCR2 as a receptor mediating NADPH oxidase-independent NET formation and provide evidence that this GPCR pathway is operative and druggable in cystic fibrosis lung disease.
Nature medicine 09/2010; 16(9):1018-23. · 27.14 Impact Factor
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Marcus A Mall,
Brian Button,
Bjarki Johannesson, Zhe Zhou,
Alessandra Livraghi,
Ray A Caldwell,
Susanne C Schubert,
Carsten Schultz,
Wanda K O'Neal,
Sylvain Pradervand,
Edith Hummler,
Bernard C Rossier,
Barbara R Grubb,
Richard C Boucher
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ABSTRACT: Studies in cystic fibrosis patients and mice overexpressing the epithelial Na(+) channel beta-subunit (betaENaC-Tg) suggest that raised airway Na(+) transport and airway surface liquid (ASL) depletion are central to the pathogenesis of cystic fibrosis lung disease. However, patients or mice with Liddle gain-of-function betaENaC mutations exhibit hypertension but no lung disease. To investigate this apparent paradox, we compared the airway phenotype (nasal versus tracheal) of Liddle with CFTR-null, betaENaC-Tg, and double mutant mice. In mouse nasal epithelium, the region that functionally mimics human airways, high levels of CFTR expression inhibited Liddle epithelial Nat channel (ENaC) hyperfunction. Conversely, in mouse trachea, low levels of CFTR failed to suppress Liddle ENaC hyperfunction. Indeed, Na(+) transport measured in Ussing chambers ("flooded" conditions) was raised in both Liddle and betaENaC-Tg mice. Because enhanced Na(+) transport did not correlate with lung disease in these mutant mice, measurements in tracheal cultures under physiologic "thin film" conditions and in vivo were performed. Regulation of ASL volume and ENaC-mediated Na(+) absorption were intact in Liddle but defective in betaENaC-Tg mice. We conclude that the capacity to regulate Na(+) transport and ASL volume, not absolute Na(+) transport rates in Ussing chambers, is the key physiologic function protecting airways from dehydration-induced lung disease.
Journal of Biological Chemistry 08/2010; 285(35):26945-55. · 4.77 Impact Factor
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ABSTRACT: Increased airway Na(+) absorption mediated by epithelial Na(+) channels (ENaC) is a characteristic abnormality in the pathogenesis of cystic fibrosis (CF) lung disease. However, inhalation therapy with the ENaC blocker amiloride did not have therapeutic benefits in patients with CF with established lung disease.
We hypothesized that preventive inhibition of increased Na(+) absorption in a structurally normal lung may be required for effective therapy of CF lung disease in vivo, and that therapeutic effects of late amiloride intervention may be impeded by the chronic disease process.
To test this hypothesis in vivo, we used the betaENaC-overexpression mouse as a model of CF lung disease and determined therapeutic effects of preventive versus late amiloride therapy on survival, airway mucus plugging, chronic bronchitis, and airway remodeling.
We show that early intervention, i.e., from the first day of life, with the intranasal administration of amiloride significantly reduced pulmonary mortality, airway mucus obstruction, epithelial necrosis, goblet cell metaplasia, and airway inflammation in betaENaC-overexpressing mice. In contrast, consistent with previous human trials in patients with CF, amiloride administration did not have benefits if treatment was started after the development of CF-like lung disease in betaENaC-overexpressing mice.
We conclude that preventive inhibition of increased airway Na(+) absorption provides an effective therapy for CF-like lung disease in vivo. These results suggest that amiloride therapy may be an effective preventive therapy for patients with CF if initiated early in life before the onset of lung disease.
American Journal of Respiratory and Critical Care Medicine 11/2008; 178(12):1245-56. · 11.08 Impact Factor
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Marcus A Mall,
Jack R Harkema,
Joanna B Trojanek,
Diana Treis,
Alessandra Livraghi,
Susanne Schubert, Zhe Zhou,
Silvia M Kreda,
Stephen L Tilley,
Elizabeth J Hudson,
Wanda K O'Neal,
Richard C Boucher
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ABSTRACT: Chronic obstructive pulmonary disease is a leading cause of death worldwide, but its pathogenesis is not well understood. Previous studies have shown that airway surface dehydration in beta-epithelial Na(+) channel (betaENaC)-overexpressing mice caused a chronic lung disease with high neonatal pulmonary mortality and chronic bronchitis in adult survivors.
The aim of this study was to identify the initiating lesions and investigate the natural progression of lung disease caused by airway surface dehydration.
Lung morphology, gene expression, bronchoalveolar lavage, and lung mechanics were studied at different ages in betaENaC-overexpressing mice.
Mucus obstruction in betaENaC-overexpressing mice originated in the trachea in the first days of life and was associated with hypoxia, airway epithelial necrosis, and death. In surviving betaENaC-overexpressing mice, mucus obstruction extended into the lungs and was accompanied by goblet cell metaplasia, increased mucin expression, and airway inflammation with transient perinatal increases in tumor necrosis factor-alpha and macrophages, IL-13 and eosinophils, and persistent increases in keratinocyte-derived cytokine (KC), neutrophils, and chitinases in the lung. betaENaC-overexpressing mice also developed emphysema with increased lung volumes, distal airspace enlargement, and increased lung compliance.
Our studies demonstrate that airway surface dehydration is sufficient to initiate persistent neutrophilic airway inflammation with chronic airways mucus obstruction and to cause transient eosinophilic airway inflammation and emphysema. These results suggest that deficient airway surface hydration may play a critical role in the pathogenesis of chronic obstructive pulmonary diseases of different etiologies and serve as a target for novel therapies.
American Journal of Respiratory and Critical Care Medicine 05/2008; 177(7):730-42. · 11.08 Impact Factor
