Capsaicin Potentiates Wild-Type and Mutant Cystic Fibrosis Transmembrane Conductance Regulator Chloride-Channel Currents

2004 ◽  
Vol 65 (6) ◽  
pp. 1415-1426 ◽  
Author(s):  
Tomohiko Ai ◽  
Silvia G. Bompadre ◽  
Xiaohui Wang ◽  
Shenghui Hu ◽  
Min Li ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Chloride Channel ◽  
Transmembrane Conductance Regulator ◽  
Wild Type ◽  
Transmembrane Conductance ◽  
Cystic Fibrosis Transmembrane ◽  
Channel Currents

scholarly journals Carbon monoxide-releasing molecules inhibit the cystic fibrosis transmembrane conductance regulator Cl− channel

2020 ◽  
Vol 319 (6) ◽  
pp. L997-L1009
Author(s):  
Mayuree Rodrat ◽  
Walailak Jantarajit ◽  
Demi R. S. Ng ◽  
Bartholomew S. J. Harvey ◽  
Jia Liu ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Carbon Monoxide ◽  
Current Flow ◽  
Open Channels ◽  
Transmembrane Conductance Regulator ◽  
Channel Activity ◽  
Wild Type ◽  
Transmembrane Conductance ◽  
Flow Through ◽  
Cystic Fibrosis Transmembrane

The gasotransmitter carbon monoxide (CO) regulates fluid and electrolyte movements across epithelial tissues. However, its action on anion channels is incompletely understood. Here, we investigate the direct action of CO on the cystic fibrosis transmembrane conductance regulator (CFTR) by applying CO-releasing molecules (CO-RMs) to the intracellular side of excised inside-out membrane patches from cells heterologously expressing wild-type human CFTR. Addition of increasing concentrations of tricarbonyldichlororuthenium(II) dimer (CORM-2) (1–300 μM) inhibited CFTR channel activity, whereas the control RuCl3 (100 μM) was without effect. CORM-2 predominantly inhibited CFTR by decreasing the frequency of channel openings and, hence, open probability ( Po). But, it also reduced current flow through open channels with very fast kinetics, particularly at elevated concentrations. By contrast, the chemically distinct CO-releasing molecule CORM-3 inhibited CFTR by decreasing Po without altering current flow through open channels. Neither depolarizing the membrane voltage nor raising the ATP concentration on the intracellular side of the membrane affected CFTR inhibition by CORM-2. Interestingly, CFTR inhibition by CORM-2, but not by CFTRinh-172, was prevented by prior enhancement of channel activity by the clinically approved CFTR potentiator ivacaftor. Similarly, when added after CORM-2, ivacaftor completely relieved CFTR inhibition. In conclusion, CORM-2 has complex effects on wild-type human CFTR consistent with allosteric inhibition and open-channel blockade. Inhibition of CFTR by CO-releasing molecules suggests that CO regulates CFTR activity and that the gasotransmitter has tissue-specific effects on epithelial ion transport. The action of ivacaftor on CFTR Cl− channels inhibited by CO potentially expands the drug’s clinical utility.

scholarly journals Influence of Cystic Fibrosis Transmembrane Conductance Regulator on Gene Expression in Response to Pseudomonas aeruginosa Infection of Human Bronchial Epithelial Cells

2005 ◽  
Vol 73 (10) ◽  
pp. 6822-6830 ◽  
Author(s):  
Nina Reiniger ◽  
Jeffrey K. Ichikawa ◽  
Gerald B. Pier
Keyword(s):  
Cystic Fibrosis ◽  
Cell Line ◽  
Cell Lines ◽  
The Other ◽  
Transmembrane Conductance Regulator ◽  
Wild Type ◽  
Transmembrane Conductance ◽  
Bronchial Epithelial ◽  
Cystic Fibrosis Transmembrane ◽  
In Cells

ABSTRACT Chronic lung infection by Pseudomonas aeruginosa causes significant morbidity in cystic fibrosis patients initiated by the failure of innate immune responses. We used microarray analysis and real-time PCR to detect transcriptional changes associated with cytokine production in isogenic bronchial epithelial cell lines with either wild-type (WT) or mutant cystic fibrosis transmembrane conductance regulator (CFTR) in response to P. aeruginosa infection. The transcription of four NF-κB-regulated cytokine genes was maximal in the presence of WT CFTR: the interleukin-8 (IL-8), IL-6, CXCL1, and intracellular adhesion molecule 1 (ICAM-1) genes. Analysis of protein expression in two cell lines paired for wild-type and mutant CFTR with three P. aeruginosa strains showed IL-6 and IL-8 expressions were consistently enhanced by the presence of WT CFTR in both cell lines with all three strains of P. aeruginosa, although some strains gave small IL-8 increases in cells with mutant CFTR. CXCL1 production showed consistent enhancement in cells with WT CFTR using all three bacterial strains in one cell line, whereas in the other cell line, CXCL1 showed a significant increase in cells with either WT or mutant CFTR. ICAM-1 was unchanged at the protein level in one of the cell lines but did show mild enhancement with WT CFTR in the other cell pair. Inhibitions of NF-κB prior to infection indicated differing degrees of dependence on NF-κB for production of the cytokines, contingent on the cell line. Cytokine effectors of innate immunity to P. aeruginosa were found to be positively influenced by the presence of WT CFTR, indicating a role in resistance to P. aeruginosa infection.

scholarly journals Enhancement of alveolar epithelial sodium channel activity with decreased cystic fibrosis transmembrane conductance regulator expression in mouse lung

2011 ◽  
Vol 301 (4) ◽  
pp. L557-L567 ◽  
Author(s):  
Ahmed Lazrak ◽  
Asta Jurkuvenaite ◽  
Lan Chen ◽  
Kim M. Keeling ◽  
James F. Collawn ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Epithelial Cells ◽  
Alveolar Epithelial Cells ◽  
Alveolar Type ◽  
Transmembrane Conductance Regulator ◽  
Wild Type ◽  
Transmembrane Conductance ◽  
Alveolar Epithelial ◽  
Cystic Fibrosis Transmembrane

We sought to establish whether the cystic fibrosis transmembrane conductance regulator (CFTR) regulates the activity of amiloride-sensitive sodium channels (ENaC) in alveolar epithelial cells of wild-type, heterozygous ( Cftr +/−), knockout ( Cftr −/−), and ΔF508-expressing mice in situ. RT-PCR studies confirmed the presence of CFTR message in freshly isolated alveolar type II (ATII) cells from wild-type mice. We patched alveolar type I (ATI) and ATII cells in freshly prepared lung slices from these mice and demonstrated the presence of 4-pS ENaC channels with the following basal open probabilities (Po): wild-type=0.21 ± 0.015: Cftr +/−=0.4 ± 0.03; ΔF508=0.55 ± 0.01; and Cftr −/−=and 0.81 ± 0.016 (means ± SE; n ≥ 9). Forskolin (5 μM) or trypsin (2 μM), applied in the pipette solution, increased the Po and number of channels in ATII cells of wild-type, Cftr +/−, and ΔF508, but not in Cftr −/− mice, suggesting that the latter were maximally activated. Western blot analysis showed that lungs of all groups of mice had similar levels of α-ENaC; however, lungs of Cftr +/− and Cftr −/− mice had significantly higher levels of an α-ENaC proteolytic fragment (65 kDa) that is associated with active ENaC channels. Our results indicate that ENaC activity is inversely correlated to predicted CFTR levels and that CFTR heterozygous and homozygous mice have higher levels of proteolytically processed ENaC fragments in their lungs. This is the first demonstration of functional ENaC-CFTR interactions in alveolar epithelial cells in situ.

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