Airway Surface Dehydration by Transforming Growth Factor β (TGF-β) in Cystic Fibrosis Is Due to Decreased Function of a Voltage-dependent Potassium Channel and Can Be Rescued by the Drug Pirfenidone

Manzanares, Dahis; Krick, Stefanie; Baumlin, Nathalie; Dennis, John S.; Tyrrell, Jean; Tarran, Robert; Salathé, Matthias

doi:10.1074/jbc.m115.670885

Cited by 43 publications

(58 citation statements)

References 29 publications

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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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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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“…There, TGF-β1 levels correlate with the severity of obstruction 27 – 29 . In cystic fibrosis (CF), TGF-β1 has been described to cause mucociliary dysfunction by reducing ASL volume via decreased apical BK channel activity 11 through a down-regulation of Leucine Rich Repeat Containing protein 26 (LRRC26), the γ subunit necessary for BK function in non-excitable tissues 30 . By activating cell surface receptors, TGF-β induces Smad2/Smad3 phosphorylation, which triggers the translocation of the complex to the nucleus where it affects chromatin remodelling and the transcription of target responsive genes 31 .…”

Section: Introductionmentioning

confidence: 99%

Role of Smad3 and p38 Signalling in Cigarette Smoke-induced CFTR and BK dysfunction in Primary Human Bronchial Airway Epithelial Cells

Sailland

Grosche

Baumlin

et al. 2017

Sci Rep

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Mucociliary clearance (MCC) is a major airway host defence system that is impaired in patients with smoking-associated chronic bronchitis. This dysfunction is partially related to a decrease of airway surface liquid (ASL) volume that is in part regulated by apically expressed cystic fibrosis transmembrane conductance regulator (CFTR) and large-conductance, Ca2+-activated, and voltage dependent K+ (BK) channels. Here, data from human bronchial epithelial cells (HBEC) confirm that cigarette smoke not only downregulates CFTR activity but also inhibits BK channel function, thereby causing ASL depletion. Inhibition of signalling pathways involved in cigarette smoke-induced channel dysfunction reveals that CFTR activity is downregulated via Smad3 signalling whereas BK activity is decreased via the p38 cascade. In addition, pre-treatment with pirfenidone, a drug presently used to inhibit TGF-β signalling in idiopathic pulmonary fibrosis, ameliorated BK dysfunction and ASL volume loss. Taken together, our results highlight the importance of not only CFTR but also BK channel function in maintaining ASL homeostasis and emphasize the possibility that pirfenidone could be employed as a novel therapeutic regimen to help improve MCC in smoking-related chronic bronchitis.

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“…Native BK channels exhibit a wide range of biophysical, pharmacological, and functional properties that differ among various cell types (Ding, Li, & Lingle, 1998; Gessner et al, 2005; Jones, Gray-Keller, Art, & Fettiplace, 1999; Xia, Ding, & Lingle, 1999), at different stages of development (Carvalho-de-Souza, Varanda, Tostes, & Chignalia, 2013), and in different physiological or pathological conditions (Hu et al, 2011; Manzanares et al, 2015; Tao et al, 2015). BK channels with slightly different biophysical properties can be produced by alternative splicing of KCNMA1 precursor mRNA at several different sites (Glauser, Johnson, Aldrich, & Goodman, 2011; Ramanathan, Michael, Jiang, Hiel, & Fuchs, 1999; Saito, Nelson, Salkoff, & Lingle, 1997; Schreiber, Yuan, & Salkoff, 1999; Yu, Upadhyaya, & Atkinson, 2006).…”

Section: Introductionmentioning

confidence: 99%

Modulation of BK Channel Function by Auxiliary Beta and Gamma Subunits

Yan

2016

International Review of Neurobiology

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The large-conductance, Ca2+- and voltage-activated K+ (BK) channel is ubiquitously expressed in mammalian tissues and displays diverse biophysical or pharmacological characteristics. This diversity is in part conferred by channel modulation with different regulatory auxiliary subunits. To date, two distinct classes of BK channel auxiliary subunits have been identified: β subunits and γ subunits. Modulation of BK channels by the four auxiliary β (β1–β4) subunits has been well established and intensively investigated over the past two decades. The auxiliary γ subunits, however, were identified only very recently, which adds a new dimension to BK channel regulation and improves our understanding of the physiological functions of BK channels in various tissues and cell types. This chapter will review the current understanding of BK channel modulation by auxiliary β and γ subunits, especially the latest findings.

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Airway Surface Dehydration by Transforming Growth Factor β (TGF-β) in Cystic Fibrosis Is Due to Decreased Function of a Voltage-dependent Potassium Channel and Can Be Rescued by the Drug Pirfenidone

Cited by 43 publications

References 29 publications

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

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

Role of Smad3 and p38 Signalling in Cigarette Smoke-induced CFTR and BK dysfunction in Primary Human Bronchial Airway Epithelial Cells

Modulation of BK Channel Function by Auxiliary Beta and Gamma Subunits

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