scholarly journals Chlorzoxazone or 1-EBIO increases Na+absorption across cystic fibrosis airway epithelial cells

2001 ◽  
Vol 281 (5) ◽  
pp. L1123-L1129 ◽  
Author(s):  
Lin Gao ◽  
James R. Yankaskas ◽  
Catherine M. Fuller ◽  
Eric J. Sorscher ◽  
Sadis Matalon ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Short Circuit ◽  
Fold Increase ◽  
Short Circuit Current ◽  
Airway Disease ◽  
Airway Epithelial Cells ◽  
Transmembrane Conductance Regulator ◽  
Airway Epithelial ◽  
Cystic Fibrosis Airway ◽  
Cf Transmembrane Conductance Regulator

Previous studies demonstrated that chlorzoxazone or 1-ethyl-2-benzimidazolinone (1-EBIO) enhances transepithelial Cl− secretion by increasing basolateral K+ conductance ( G K) (Singh AK, Devor DC, Gerlach AC, Gondor M, Pilewski JM, and Bridges RJ. J Pharmacol Exp Ther 292: 778–787, 2000). Hence these compounds may be useful to treat cystic fibrosis (CF) airway disease. The goal of the present study was to determine whether chlorzoxazone or 1-EBIO altered ion transport across ΔF508-CF transmembrane conductance regulator homozygous CFT1 airway cells. CFT1 monolayers exhibited a basal short-circuit current that was abolished by apical amiloride (inhibition constant 320 nM) as expected for Na+ absorption. The addition of chlorzoxazone (400 μM) or 1-EBIO (2 mM) increased the amiloride-sensitive I sc ∼2.5-fold. This overlapping specificity may preclude use of these compounds as CF therapeutics. Assaying for changes in the basolateral G K with a K+ gradient plus the pore-forming antibiotic amphotericin B revealed that chlorzoxazone or 1-EBIO evoked an ∼10-fold increase in clotrimazole-sensitive G K. In contrast, chlorzoxazone did not alter epithelial Na+ channel-mediated currents across basolateral-permeabilized monolayers or in Xenopus oocytes. These data further suggest that alterations in basolateral G K alone can modulate epithelial Na+ transport.

Cystic fibrosis and beta-adrenergic response of airway epithelial cell cultures

1986 ◽  
Vol 251 (4) ◽  
pp. R818-R822 ◽  
Author(s):  
J. H. Widdicombe
Keyword(s):  
Cystic Fibrosis ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Airway Epithelial Cells ◽  
Ionophore A23187 ◽  
Airway Epithelial ◽  
Cell Sheets ◽  
Maximal Increase ◽  
Cl Secretion ◽  
Camp Levels

Confluent cell sheets were cultured from the tracheal epithelium of normal humans or from tracheal and nasal epithelia of patients with cystic fibrosis (CF). Changes in short-circuit current (Isc) or cyclic AMP (cAMP) levels in response to 10(-5) M isoproterenol were measured. In CF tracheal cells the response to isoproterenol was transient, and the maximal increase in Isc was one-tenth normal. In CF nasal cells, isoproterenol or epinephrine caused only small transient increases in Isc. However, in both CF nasal and tracheal cells, the Ca ionophore, A23187, caused relatively large increases in Isc that were inhibited by the Cl transport blocker, bumetanide, suggesting that Cl secretion can be induced by raising intracellular levels of Ca. In normal tracheal cell sheets, cAMP levels increased within 15 s of isoproterenol addition and continued to increase for up to 20 min. Resting levels of cAMP in CF tracheal cells were not statistically different from those of normal cells and showed linear increases for up to 4 min after addition of isoproterenol. Changes in cAMP in CF nasal cells were similar to the changes in CF tracheal cells. After 2 min, all three cell types showed cAMP levels elevated approximately equal to 10-fold. These results suggest that receptor-activated stimulation of adenylate cyclase is normal in CF. However, though raised cAMP levels stimulate Cl secretion in normal, they are unable to do so in CF airway epithelial cells.

scholarly journals Naringenin Regulates CFTR Activation and Expression in Airway Epithelial Cells

2017 ◽  
Vol 44 (3) ◽  
pp. 1146-1160 ◽  
Author(s):  
Rui Shi ◽  
Zi-Ting Xiao ◽  
Yi-Jun Zheng ◽  
Yi-Lin Zhang ◽  
Jia-Wen Xu ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Short Circuit ◽  
Short Circuit Current ◽  
The Elderly ◽  
Airway Epithelial Cells ◽  
Intracellular Camp ◽  
Transmembrane Conductance Regulator ◽  
Airway Epithelial ◽  
Camp Content ◽  
Basolateral Side

Background/Aims: Sputum symptoms are commonly seen in the elderly. This study aimed to identify an efficacious expectorant treatment stratagem through evaluating the secretion-promoting activation and cystic fibrosis transmembrane conductance regulator (CFTR) expression of the bioactive herbal monomer naringenin. Methods: Vectorial Cl- transport was determined by measuring short-circuit current (ISC) in rat airway epithelium. cAMP content was measured by ELISA in primary cultured epithelial cells and Calu-3 cells. CFTR expression in Calu-3 cells was determined by qPCR. Results: Addition of naringenin to the basolateral side of the rat airway led to a concentration-dependent sustained increase in ISC. The current was suppressed when exposed to Cl–-free solution or by bumetanide, BaCl2, and DPC but not by DIDS and IBMX. Forskolin-induced ISC increase and CFTRinh-172/MDL-12330A-induced ISC inhibition were not altered by naringenin. Intracellular cAMP content was significantly increased by naringenin. With lipopolysaccharide stimulation, CFTR expression was significantly reduced, and naringenin dose-dependently enhanced CFTR mRNA expression. Conclusion: These results demonstrate that naringenin has the ability to stimulate Cl- secretion, which is mediated by CFTR through a signaling pathway by increasing cAMP content. Moreover, naringenin can increase CFTR expression when organism CFTR expression is seriously hampered. Our data suggest a potentially effective treatment strategy for sputum.

scholarly journals Modulation of Ion Transport to Restore Airway Hydration in Cystic Fibrosis

Genes ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 453
Author(s):  
James A. Reihill ◽  
Lisa E. J. Douglas ◽  
S. Lorraine Martin
Keyword(s):  
Cystic Fibrosis ◽  
Epithelial Cells ◽  
Genetic Disorder ◽  
Airway Epithelial Cells ◽  
Transmembrane Conductance Regulator ◽  
Airway Epithelial ◽  
Loss Of Function ◽  
Transmembrane Conductance ◽  
Infection And Inflammation ◽  
Cf Transmembrane Conductance Regulator

Cystic fibrosis (CF) is a life-limiting genetic disorder caused by loss-of-function mutations in the gene which codes for the CF transmembrane conductance regulator (CFTR) Cl− channel. Loss of Cl− secretion across the apical membrane of airway lining epithelial cells results in dehydration of the airway surface liquid (ASL) layer which impairs mucociliary clearance (MCC), and as a consequence promotes bacterial infection and inflammation of the airways. Interventions that restore airway hydration are known to improve MCC. Here we review the ion channels present at the luminal surface of airway epithelial cells that may be targeted to improve airway hydration and MCC in CF airways.

Enhanced colonic Na+ absorption in cystic fibrosis mice versus normal mice

1997 ◽  
Vol 272 (2) ◽  
pp. G393-G400 ◽  
Author(s):  
B. R. Grubb ◽  
R. C. Boucher
Keyword(s):  
Cystic Fibrosis ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Distal Colon ◽  
Proximal Colon ◽  
Na Channel ◽  
Transmembrane Conductance Regulator ◽  
Transmembrane Conductance ◽  
Constant Dose ◽  
Cf Transmembrane Conductance Regulator

Because there are reports that electrogenic Na+ absorption is increased in colonic epithelia of cystic fibrosis (CF) subjects, we tested whether amiloride-sensitive Na+ absorption was increased in the colonic epithelia of CF mice compared with normal mice on high- or low-Na+ diets. When mice consumed a diet high in Na+, none of the colonic regions (distal colon, proximal colon, or cecum) from either group of mice exhibited an amiloride-sensitive short-circuit current (Isc). However, when mice were placed on a low-Na+ diet for 2 wk, all three intestinal regions from the CF mice exhibited a significant response to amiloride (P < or = 0.05). In contrast, normal mice on the low-Na+ diet exhibited an amiloride-sensitive Isc that was smaller and only significant in the cecum and distal colon. Measurement of plasma aldosterone levels revealed that the CF mice on the low-Na+ diet had significantly greater aldosterone levels than similarly treated controls [8,906 +/- 1,039 (n = 14) vs. 5,243 +/- 1,410 pg/ml (n = 14), respectively]. When mice were infused with a constant dose of aldosterone (1 microg x g(-1) x day(-1)) for 7 days, the distal colon of the CF mice still had a significantly greater amiloride-sensitive Isc than did the normal distal colon. If the presence of CF transmembrane conductance regulator (CFTR) down-regulates Na+ absorption in the colonic tissue from normal mice, our data suggest that at least some CFTR may be colocalized with the Na+ channel. Alternatively, other factors may be involved.

Treating the Airway Consequences of Cystic Fibrosis Transmembrane Conductance Regulator Dysfunction

2019 ◽  
Vol 40 (06) ◽  
pp. 751-761
Author(s):  
Demet Toprak ◽  
Chelsea Davis ◽  
Margaret Rosenfeld
Keyword(s):  
Cystic Fibrosis ◽  
Airway Epithelial Cells ◽  
Transmembrane Conductance Regulator ◽  
Airway Epithelial ◽  
National Guidelines ◽  
Transmembrane Conductance ◽  
Infection And Inflammation ◽  
Surface Liquid ◽  
Cf Transmembrane Conductance Regulator ◽  
Cystic Fibrosis Transmembrane

AbstractIn cystic fibrosis (CF), absent or dysfunctional CF transmembrane conductance regulator (CFTR) on the surface of airway epithelial cells causes abnormal mucociliary clearance, leading to chronic endobronchial infection and inflammation, in turn resulting in life-shortening progressive obstructive lung disease and structural airway damage. Fortunately, CF-specific therapies have been developed that improve lung function and reduce pulmonary exacerbations, contributing significantly to improved survival over the past 4 decades. Therapies not originally developed for CF, such as bronchodilators and corticosteroids, are also widely used by people living with CF. Therapies to be reviewed in this article include mucolytics, airway surface liquid hydrators, anti-inflammatory medications, bronchodilators, inhaled and oral antibiotics, and airway clearance techniques. Determining which therapies to utilize can be challenging, as there is variable evidence for each treatment, differing national guidelines, few head-to-head studies, potential for drug–drug interactions, and synergistic toxicities, as well as issues with burden of care. In this review, we summarize the mechanism of action and available evidence, and compare national guidelines for each major medication used to treat the airway consequences of CFTR dysfunction.

Partial correction of defective Cl− secretion in cystic fibrosis epithelial cells by an analog of squalamine

2001 ◽  
Vol 281 (5) ◽  
pp. L1164-L1172 ◽  
Author(s):  
Canwen Jiang ◽  
Edward R. Lee ◽  
Mathieu B. Lane ◽  
Yong-Fu Xiao ◽  
David J. Harris ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Epithelial Cells ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Airway Epithelial Cells ◽  
Synthetic Analog ◽  
Airway Epithelial ◽  
Thyroid Cells ◽  
Rat Thyroid ◽  
Partial Correction

Defective cystic fibrosis (CF) transmembrane conductance regulator (CFTR)-mediated Cl− transport across the apical membrane of airway epithelial cells is implicated in the pathophysiology of CF lungs. A strategy to compensate for this loss is to augment Cl− transport through alternative pathways. We report here that partial correction of this defect could be attained through the incorporation of artificial anion channels into the CF cells. Introduction of GL-172, a synthetic analog of squalamine, into CFT1 cells increased cell membrane halide permeability. Furthermore, when a Cl− gradient was generated across polarized monolayers of primary human airway or Fischer rat thyroid cells in an Ussing chamber, addition of GL-172 caused an increase in the equivalent short-circuit current. The magnitude of this change in short-circuit current was ∼30% of that attained when CFTR was maximally stimulated with cAMP agonists. Patch-clamp studies showed that addition of GL-172 to CFT1 cells also increased whole cell Cl− currents. These currents displayed a linear current-voltage relationship and no time dependence. Additionally, administration of GL-172 to the nasal epithelium of transgenic CF mice induced a hyperpolarization response to perfusion with a low-Cl− solution, indicating restoration of Cl− secretion. Together, these results demonstrate that in CF airway epithelial cells, administration of GL-172 is capable of partially correcting the defective Cl− secretion.

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