Functional Apical Large Conductance, Ca2+-activated, and Voltage-dependent K+ Channels Are Required for Maintenance of Airway Surface Liquid Volume

Manzanares, Dahis; González, Carlos; Ivonnet, Pedro; Chen, Ren Shiang; Valencia-Gattas, Monica; Conner, Gregory E.; Larsson, H. Peter; Salathé, Matthias

doi:10.1074/jbc.m110.185074

Cited by 77 publications

(71 citation statements)

References 63 publications

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“…Ion channel conductance for CFTR was significantly reduced in cells exposed to nicotine-containing e-cigarette vapours 8 hours after exposure (figure 6E), and was independent of the expression of the CFTR gene (figure 6F). Ion channel conductance for the BK channel was also significantly reduced in cells exposed to nicotine-containing e-cigarette vapours at 8 hours after exposure (figure 6G), which coincided with reduced expression of BK channel α subunit ( KCNMA1 ) gene that regulates ASL 25. ASL volume changes showed a significant decrease, from 14.6±2 µL in cells exposed to nicotine-free e-cigarette vapour at 24 hours after exposure to 3.8±1 µL in cells exposed to nicotine-containing e-cigarette vapour (mean±SEM; p<0.01; figure 6I).…”

Section: Resultsmentioning

confidence: 91%

Chronic electronic cigarette exposure in mice induces features of COPD in a nicotine-dependent manner

García-Arcos

Geraghty

Baumlin

et al. 2016

Thorax

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276

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BackgroundThe use of electronic (e)-cigarettes is increasing rapidly, but their lung health effects are not established. Clinical studies examining the potential long-term impact of e-cigarette use on lung health will take decades. To address this gap in knowledge, this study investigated the effects of exposure to aerosolised nicotine-free and nicotine-containing e-cigarette fluid on mouse lungs and normal human airway epithelial cells.MethodsMice were exposed to aerosolised phosphate-buffered saline, nicotine-free or nicotine-containing e-cigarette solution, 1-hour daily for 4 months. Normal human bronchial epithelial (NHBE) cells cultured at an air-liquid interface were exposed to e-cigarette vapours or nicotine solutions using a Vitrocell smoke exposure robot.ResultsInhalation of nicotine-containing e-cigarettes increased airway hyper-reactivity, distal airspace enlargement, mucin production, cytokine and protease expression. Exposure to nicotine-free e-cigarettes did not affect these lung parameters. NHBE cells exposed to nicotine-containing e-cigarette vapour showed impaired ciliary beat frequency, airway surface liquid volume, cystic fibrosis transmembrane regulator and ATP-stimulated K+ ion conductance and decreased expression of FOXJ1 and KCNMA1. Exposure of NHBE cells to nicotine for 5 days increased interleukin (IL)-6 and IL-8 secretion.ConclusionsExposure to inhaled nicotine-containing e-cigarette fluids triggered effects normally associated with the development of COPD including cytokine expression, airway hyper-reactivity and lung tissue destruction. These effects were nicotine-dependent both in the mouse lung and in human airway cells, suggesting that inhaled nicotine contributes to airway and lung disease in addition to its addictive properties. Thus, these findings highlight the potential dangers of nicotine inhalation during e-cigarette use.

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Section: Resultsmentioning

confidence: 91%

Chronic electronic cigarette exposure in mice induces features of COPD in a nicotine-dependent manner

García-Arcos

Geraghty

Baumlin

et al. 2016

Thorax

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276

263

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“…A deficit in ASL volume contributes to the pathogenesis of CF (41), and increased ASL volumes increase mucociliary clearance (42,43). ASL volume is controlled in part by anion secretion and the corresponding movement of Na 1 and K 1 to and from the mucosal surface (1,44). CFTR channel activity is essential for the regulation of this process.…”

Section: Discussionmentioning

confidence: 99%

H₂O₂ Stimulates Cystic Fibrosis Transmembrane Conductance Regulator through an Autocrine Prostaglandin Pathway, Using Multidrug-Resistant Protein–4

Conner

Ivonnet²,

Gelin³

et al. 2013

Am J Respir Cell Mol Biol

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Cystic fibrosis transmembrane conductance regulator (CFTR) activity is essential for the maintenance of airway surface liquid depth, and therefore mucociliary clearance. Reactive oxygen species, increased during inflammatory airway diseases, alter CFTR activity. Here, H 2 O 2 levels in the surface liquid of normal human bronchial epithelial cultures differentiated at the air-liquid interface were estimated, and H 2 O 2 -mediated changes in CFTR activity were examined. In Ussing chambers, H 2 O 2 -induced anion currents were sensitive to the CFTR inhibitors CFTR inh 172 and GlyH-101. These currents were absent in cells from patients with cystic fibrosis. Effective airway clearance relies on the regulation of ciliary beat frequency (CBF), adequate airway surface liquid (ASL) volume, and correct mucus properties. Mucus hydration and thus the viscosity of mucus depend, in part, on the movement of water through the airway epithelium to the mucosal surface via the coordinated activities of ion channels. An important player in this regulation is the cystic fibrosis transmembrane conductance regulator (CFTR) that passes chloride (and other anions) while regulating the epithelial Na 1 channel to balance osmolarity (1). CFTR and CBF are both regulated through increases in cyclic adenosine monophosphate (cAMP) and protein kinase A activity (2-4). Thus, mediators that stimulate adenylyl cyclase are expected to result in improved airway clearance by increasing chloride secretion and CBF.Airway epithelia actively synthesize H 2 O 2 via the nicotinamide adenine dinucleotide phosphate-reduced (NADPH) dual oxidases Duox1 and Duox2, as reviewed by Fischer (5), presumably for the use of the lactoperoxidase host defense against infection (6-9). Duox1 and Duox2 are regulated by cytokines (10-12) and bacterial products (10,13,14) to increase H 2 O 2 synthesis to high levels (10). Stimulation with interferon-g increased H 2 O 2 synthesis levels 30-fold when measured in air-liquid interface (ALI) cultures of normal human airway epithelial cells (10), leading to 10 mM H 2 O 2 in washes used for assays. The experiments presented here address ASL H 2 O 2 and show that it is present at high concentrations.In addition to its role in stimulating lactoperoxidase host defense, H 2 O 2 may also regulate the innate defense related to mucociliary clearance. In the bronchial submucosal adenocarcinoma cell line Calu-3, CFTR activity is increased by exposure of the airway epithelium to exogenous H 2 O 2 (15, 16). In cell lines, the effect of H 2 O 2 on CFTR is reported to occur through increases in transmembrane adenylyl cyclase activity and through the activation of two K 1 channels (15), most likely KCNQ1 and KCNN4, which are located in the basolateral membrane. These channels are believed to provide a driving force for apical Cl 2 release (17, 18). Yet the mechanisms by which H 2 O 2 leads to the activation of the cAMP pathway are not understood. Although both Calu-3 cells (19) and bovine tracheal epithelia (20) have been shown to respond to isop...

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“…mRNA levels were assayed by real-time PCR using TaqMan kits as described previously (15), and Western blotting was done as above. We have been successful in knocking down several proteins in fully differentiated airway epithelial cells (5,25,26).…”

Section: Methodsmentioning

confidence: 99%

Dual Oxidase 2 (Duox2) Regulates Pannexin 1-mediated ATP Release in Primary Human Airway Epithelial Cells via Changes in Intracellular pH and Not H2O2 Production

Krick¹,

Wang

St-Pierre³

et al. 2016

Journal of Biological Chemistry

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ATP is a key regulator of the innate pulmonary host defense by activating purinergic P2Y2 receptors, which promote chloride secretion by calcium-activated Cl Ϫ channels, inhibit Na ϩ absorption by epithelial Na ϩ channels, increase ciliary beat frequency and airway surface liquid volume, and induce mucin release, thereby activating mucociliary clearance (1-4).Although the effects of ATP on airway epithelial cells have been studied widely, Panx1 channels have only been recognized recently to be involved in ATP release in these tissues (5, 6). Mechanical stress has been shown to be one of the prime stimuli to increase the ATP concentration on the airway surface to a concentration sufficient to activate P2Y2 receptors (7). This ATP release was neither dependent on the intracellular calcium concentration, excluding an exocytotic release mechanism, nor caused by the cystic fibrosis transmembrane conductance regulator. In previous studies, we were the first to show that Panx1, an ortholog of the invertebrate innexin, is expressed at the apical membrane of airway epithelia, contributing to ATP release (5).Pannexin proteins form pannexons, which are channels that open at resting membrane potential because of mechanical stress and in response to extracellular ATP when co-expressed with P2Y2 receptors (8, 9). In addition to stimulated ATP release, resting ATP levels on the apical surface reflect a steady state that, depending on its range, can help autoregulate the release or metabolism of ATP.Currently little is known about the physiological regulation of pannexin channels in the airway epithelium. Most studies have been performed on oocytes or transfected HEK cells. These studies demonstrated that ATP itself is a potent regulator by increasing the permeability of Panx1 initially when coexpressed with P2Y2 receptors but, consequently, causing inhibition as a feedback loop (10, 11).The cytokine IFN-␥ is produced in inflammatory airway diseases such as severe asthma (12, 13) and chronic bronchitis with and without airflow obstruction (14). We have shown that IFN-␥ can increase H 2 O 2 production via increased expression of Duox2, a member of the NADPH oxidase gene family, in ALI 2 cultures (15, 16). In addition to H 2 O 2 , Duox also releases cytosolic H ϩ (17), which could contribute to intracellular acidification. Consequently, a decrease in intracellular pH could decrease mucociliary function by direct inhibition of the ciliary beat frequency (18). In fact, Duox is up-regulated in chronic bronchitis and patients with smoke exposure (15,19,20). Preliminary data also suggested that intracellular pH is essential in

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Functional Apical Large Conductance, Ca2+-activated, and Voltage-dependent K+ Channels Are Required for Maintenance of Airway Surface Liquid Volume

Cited by 77 publications

References 63 publications

Chronic electronic cigarette exposure in mice induces features of COPD in a nicotine-dependent manner

Chronic electronic cigarette exposure in mice induces features of COPD in a nicotine-dependent manner

H₂O₂ Stimulates Cystic Fibrosis Transmembrane Conductance Regulator through an Autocrine Prostaglandin Pathway, Using Multidrug-Resistant Protein–4

Dual Oxidase 2 (Duox2) Regulates Pannexin 1-mediated ATP Release in Primary Human Airway Epithelial Cells via Changes in Intracellular pH and Not H2O2 Production

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Functional Apical Large Conductance, Ca2+-activated, and Voltage-dependent K+ Channels Are Required for Maintenance of Airway Surface Liquid Volume

Cited by 77 publications

References 63 publications

Chronic electronic cigarette exposure in mice induces features of COPD in a nicotine-dependent manner

Chronic electronic cigarette exposure in mice induces features of COPD in a nicotine-dependent manner

H2O2 Stimulates Cystic Fibrosis Transmembrane Conductance Regulator through an Autocrine Prostaglandin Pathway, Using Multidrug-Resistant Protein–4

Dual Oxidase 2 (Duox2) Regulates Pannexin 1-mediated ATP Release in Primary Human Airway Epithelial Cells via Changes in Intracellular pH and Not H2O2 Production

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H₂O₂ Stimulates Cystic Fibrosis Transmembrane Conductance Regulator through an Autocrine Prostaglandin Pathway, Using Multidrug-Resistant Protein–4