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Han X, Li D, Zhu Y, Schneider-Futschik EK. Recommended Tool Compounds for Modifying the Cystic Fibrosis Transmembrane Conductance Regulator Channel Variants. ACS Pharmacol Transl Sci 2024; 7:933-950. [PMID: 38633590 PMCID: PMC11019735 DOI: 10.1021/acsptsci.3c00362] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Revised: 02/20/2024] [Accepted: 02/23/2024] [Indexed: 04/19/2024]
Abstract
Cystic fibrosis (CF) is a genetic disorder arising from variations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene, leading to multiple organ system defects. CFTR tool compounds are molecules that can modify the activity of the CFTR channel. Especially, patients that are currently not able to benefit from approved CFTR modulators, such as patients with rare CFTR variants, benefit from further research in discovering novel tools to modulate CFTR. This Review explores the development and classification of CFTR tool compounds, including CFTR blockers (CFTRinh-172, GlyH-101), potentiators (VRT-532, Genistein), correctors (VRT-325, Corr-4a), and other approved and unapproved modulators, with detailed descriptions and discussions for each compound. The challenges and future directions in targeting rare variants and optimizing drug delivery, and the potential synergistic effects in combination therapies are outlined. CFTR modulation holds promise not only for CF treatment but also for generating CF models that contribute to CF research and potentially treating other diseases such as secretory diarrhea. Therefore, continued research on CFTR tool compounds is critical.
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Affiliation(s)
- XiaoXuan Han
- Department of Biochemistry & Pharmacology,
School of Biomedical Sciences, Faculty of Medicine, Dentistry and
Health Sciences, The University of Melbourne, Parkville, VIC 3010, Australia
| | - Danni Li
- Department of Biochemistry & Pharmacology,
School of Biomedical Sciences, Faculty of Medicine, Dentistry and
Health Sciences, The University of Melbourne, Parkville, VIC 3010, Australia
| | - Yimin Zhu
- Department of Biochemistry & Pharmacology,
School of Biomedical Sciences, Faculty of Medicine, Dentistry and
Health Sciences, The University of Melbourne, Parkville, VIC 3010, Australia
| | - Elena K. Schneider-Futschik
- Department of Biochemistry & Pharmacology,
School of Biomedical Sciences, Faculty of Medicine, Dentistry and
Health Sciences, The University of Melbourne, Parkville, VIC 3010, Australia
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2
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Cho DY, Grayson JW, Woodworth BA. Unified Airway—Cystic Fibrosis. Otolaryngol Clin North Am 2022; 56:125-136. [DOI: 10.1016/j.otc.2022.09.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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3
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Brindani N, Gianotti A, Giovani S, Giacomina F, Di Fruscia P, Sorana F, Bertozzi SM, Ottonello G, Goldoni L, Penna I, Russo D, Summa M, Bertorelli R, Ferrera L, Pesce E, Sondo E, Galietta LJV, Bandiera T, Pedemonte N, Bertozzi F. Identification, Structure-Activity Relationship, and Biological Characterization of 2,3,4,5-Tetrahydro-1 H-pyrido[4,3- b]indoles as a Novel Class of CFTR Potentiators. J Med Chem 2020; 63:11169-11194. [PMID: 32946228 PMCID: PMC8011931 DOI: 10.1021/acs.jmedchem.0c01050] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Cystic fibrosis (CF) is a life-threatening autosomal recessive disease, caused by mutations in the CF transmembrane conductance regulator (CFTR) chloride channel. CFTR modulators have been reported to address the basic defects associated with CF-causing mutations, partially restoring the CFTR function in terms of protein processing and/or channel gating. Small-molecule compounds, called potentiators, are known to ameliorate the gating defect. In this study, we describe the identification of the 2,3,4,5-tetrahydro-1H-pyrido[4,3-b]indole core as a novel chemotype of potentiators. In-depth structure-activity relationship studies led to the discovery of enantiomerically pure 39 endowed with a good efficacy in rescuing the gating defect of F508del- and G551D-CFTR and a promising in vitro druglike profile. The in vivo characterization of γ-carboline 39 showed considerable exposure levels and good oral bioavailability, with detectable distribution to the lungs after oral administration to rats. Overall, these findings may represent an encouraging starting point to further expand this chemical class, adding a new chemotype to the existing classes of CFTR potentiators.
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Affiliation(s)
- Nicoletta Brindani
- D3-PharmaChemistry, Istituto Italiano di Tecnologia (IIT), 16163 Genova, Italy
| | - Ambra Gianotti
- UOC Genetica Medica, IRCCS Istituto Giannina Gaslini, 16147 Genova, Italy
| | - Simone Giovani
- D3-PharmaChemistry, Istituto Italiano di Tecnologia (IIT), 16163 Genova, Italy
| | - Francesca Giacomina
- D3-PharmaChemistry, Istituto Italiano di Tecnologia (IIT), 16163 Genova, Italy
| | - Paolo Di Fruscia
- D3-PharmaChemistry, Istituto Italiano di Tecnologia (IIT), 16163 Genova, Italy
| | - Federico Sorana
- D3-PharmaChemistry, Istituto Italiano di Tecnologia (IIT), 16163 Genova, Italy
| | - Sine Mandrup Bertozzi
- Analytical Chemistry and Translational Pharmacology, Istituto Italiano di Tecnologia (IIT), 16163 Genova, Italy
| | - Giuliana Ottonello
- Analytical Chemistry and Translational Pharmacology, Istituto Italiano di Tecnologia (IIT), 16163 Genova, Italy
| | - Luca Goldoni
- Analytical Chemistry and Translational Pharmacology, Istituto Italiano di Tecnologia (IIT), 16163 Genova, Italy
| | - Ilaria Penna
- D3-PharmaChemistry, Istituto Italiano di Tecnologia (IIT), 16163 Genova, Italy
| | - Debora Russo
- D3-PharmaChemistry, Istituto Italiano di Tecnologia (IIT), 16163 Genova, Italy
| | - Maria Summa
- Analytical Chemistry and Translational Pharmacology, Istituto Italiano di Tecnologia (IIT), 16163 Genova, Italy
| | - Rosalia Bertorelli
- Analytical Chemistry and Translational Pharmacology, Istituto Italiano di Tecnologia (IIT), 16163 Genova, Italy
| | - Loretta Ferrera
- UOC Genetica Medica, IRCCS Istituto Giannina Gaslini, 16147 Genova, Italy
| | - Emanuela Pesce
- UOC Genetica Medica, IRCCS Istituto Giannina Gaslini, 16147 Genova, Italy
| | - Elvira Sondo
- UOC Genetica Medica, IRCCS Istituto Giannina Gaslini, 16147 Genova, Italy
| | - Luis J V Galietta
- Telethon Institute of Genetics and Medicine (TIGEM), 80078 Pozzuoli, Italy.,Department of Translational Medical Sciences (DISMET), University of Naples Federico II, 80138 Naples, Italy
| | - Tiziano Bandiera
- D3-PharmaChemistry, Istituto Italiano di Tecnologia (IIT), 16163 Genova, Italy
| | | | - Fabio Bertozzi
- D3-PharmaChemistry, Istituto Italiano di Tecnologia (IIT), 16163 Genova, Italy
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Cho DY, Skinner D, Zhang S, Lazrak A, Lim DJ, Weeks CG, Banks CG, Han CK, Kim SK, Tearney GJ, Matalon S, Rowe SM, Woodworth BA. Korean Red Ginseng aqueous extract improves markers of mucociliary clearance by stimulating chloride secretion. J Ginseng Res 2019; 45:66-74. [PMID: 33437158 PMCID: PMC7790903 DOI: 10.1016/j.jgr.2019.09.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Revised: 08/30/2019] [Accepted: 09/06/2019] [Indexed: 11/26/2022] Open
Abstract
Background Abnormal chloride (Cl-) transport has a detrimental impact on mucociliary clearance in both cystic fibrosis (CF) and non-CF chronic rhinosinusitis. Ginseng is a medicinal plant noted to have anti-inflammatory and antimicrobial properties. The present study aims to assess the capability of red ginseng aqueous extract (RGAE) to promote transepithelial Cl- secretion in nasal epithelium. Methods Primary murine nasal septal epithelial (MNSE) [wild-type (WT) and transgenic CFTR-/-], fisher-rat-thyroid (FRT) cells expressing human WT CFTR, and TMEM16A-expressing human embryonic kidney cultures were utilized for the present experiments. Ciliary beat frequency (CBF) and airway surface liquid (ASL) depth measurements were performed using micro-optical coherence tomography (μOCT). Mechanisms underlying transepithelial Cl- transport were determined using pharmacologic manipulation in Ussing chambers and whole-cell patch clamp analysis. Results RGAE (at 30μg/mL of ginsenosides) significantly increased Cl- transport [measured as change in short-circuit current (ΔISC = μA/cm2)] when compared with control in WT and CFTR-/- MNSE (WT vs control = 49.8±2.6 vs 0.1+/-0.2, CFTR-/- = 33.5±1.5 vs 0.2±0.3, p < 0.0001). In FRT cells, the CFTR-mediated ΔISC attributed to RGAE was small (6.8 ± 2.5 vs control, 0.03 ± 0.01, p < 0.05). In patch clamp, TMEM16A-mediated currents were markedly improved with co-administration of RGAE and uridine 5-triphosphate (8406.3 +/- 807.7 pA) over uridine 5-triphosphate (3524.1 +/- 292.4 pA) or RGAE alone (465.2 +/- 90.7 pA) (p < 0.0001). ASL and CBF were significantly greater with RGAE (6.2+/-0.3 μm vs control, 3.9+/-0.09 μm; 10.4+/-0.3 Hz vs control, 7.3 ± 0.2 Hz; p < 0.0001) in MNSE. Conclusion RGAE augments ASL depth and CBF by stimulating Cl- secretion through CaCC, which suggests therapeutic potential in both CF and non-CF chronic rhinosinusitis.
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Affiliation(s)
- Do-Yeon Cho
- Department of Otolaryngology Head & Neck Surgery, University of Alabama at Birmingham, Birmingham, Alabama, United States.,Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama at Birmingham, Birmingham, Alabama, United States
| | - Daniel Skinner
- Department of Otolaryngology Head & Neck Surgery, University of Alabama at Birmingham, Birmingham, Alabama, United States
| | - Shaoyan Zhang
- Department of Otolaryngology Head & Neck Surgery, University of Alabama at Birmingham, Birmingham, Alabama, United States
| | - Ahmed Lazrak
- Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama at Birmingham, Birmingham, Alabama, United States.,Department of Anesthesiology and Perioperative Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States
| | - Dong Jin Lim
- Department of Otolaryngology Head & Neck Surgery, University of Alabama at Birmingham, Birmingham, Alabama, United States
| | - Christopher G Weeks
- Department of Otolaryngology Head & Neck Surgery, University of Alabama at Birmingham, Birmingham, Alabama, United States
| | - Catherine G Banks
- Department of Otolaryngology Head & Neck Surgery, University of Alabama at Birmingham, Birmingham, Alabama, United States
| | - Chang Kyun Han
- Korea Ginseng Research Institute, Korea Ginseng Corporation, Daejeon, Republic of Korea
| | - Si-Kwan Kim
- Department of Biomedical Chemistry, Konkuk University, Chungju, Republic of Korea
| | - Guillermo J Tearney
- Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, Massachusetts, United States
| | - Sadis Matalon
- Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama at Birmingham, Birmingham, Alabama, United States.,Department of Anesthesiology and Perioperative Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States
| | - Steven M Rowe
- Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama at Birmingham, Birmingham, Alabama, United States.,Departments of Medicine, Pediatrics, Cell Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama, United States
| | - Bradford A Woodworth
- Department of Otolaryngology Head & Neck Surgery, University of Alabama at Birmingham, Birmingham, Alabama, United States.,Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama at Birmingham, Birmingham, Alabama, United States
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5
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Cabrini G. Innovative Therapies for Cystic Fibrosis: The Road from Treatment to Cure. Mol Diagn Ther 2019; 23:263-279. [PMID: 30478715 DOI: 10.1007/s40291-018-0372-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Cystic fibrosis (CF), a life-threatening multiorgan genetic disease, is facing a new era of research and development using innovative gene-directed personalized therapies. The priority organ to cure is the lung, which suffers recurrent and chronic bacterial infection and inflammation since infancy, representing the main cause of morbidity and precocious mortality of these individuals. After the disappointing failure of gene-replacement approaches using gene therapy vectors, no single drug is presently available to repair all the CF gene defects. The impressive number of different CF gene mutations is now tackled with different chemical and biotechnological tools tailored to the specific molecular derangements, thanks to the extensive knowledge acquired over many years on the mechanisms of CF cell and organ pathology. This review provides an overview and recalls both the successes and limitations of the different experimental approaches, such as high-throughput screening on chemical libraries to discover CF gene correctors and potentiators, dual-acting compounds, read-through molecules, splicing defect repairing tools, cystic fibrosis transmembrane conductance regulator (CFTR) "amplifiers," CFTR interactome modulators and the first gene editing attempts.
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Affiliation(s)
- Giulio Cabrini
- Laboratory of Molecular Pathology, University Hospital, Verona, Italy. .,Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy.
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6
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Bose SJ, Bijvelds MJC, Wang Y, Liu J, Cai Z, Bot AGM, de Jonge HR, Sheppard DN. Differential thermostability and response to cystic fibrosis transmembrane conductance regulator potentiators of human and mouse F508del-CFTR. Am J Physiol Lung Cell Mol Physiol 2019; 317:L71-L86. [PMID: 30969810 PMCID: PMC6689747 DOI: 10.1152/ajplung.00034.2019] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Cross-species comparative studies have highlighted differences between human and mouse cystic fibrosis transmembrane conductance regulator (CFTR), the epithelial Cl- channel defective in cystic fibrosis (CF). Here, we compare the impact of the most common CF mutation F508del on the function of human and mouse CFTR heterologously expressed in mammalian cells and their response to CFTR modulators using the iodide efflux and patch-clamp techniques. Once delivered to the plasma membrane, human F508del-CFTR exhibited a severe gating defect characterized by infrequent channel openings and was thermally unstable, deactivating within minutes at 37°C. By contrast, the F508del mutation was without effect on the gating pattern of mouse CFTR, and channel activity demonstrated thermostability at 37°C. Strikingly, at all concentrations tested, the clinically approved CFTR potentiator ivacaftor was without effect on the mouse F508del-CFTR Cl- channel. Moreover, eight CFTR potentiators, including ivacaftor, failed to generate CFTR-mediated iodide efflux from CHO cells expressing mouse F508del-CFTR. However, they all produced CFTR-mediated iodide efflux with human F508del-CFTR-expressing CHO cells, while fifteen CFTR correctors rescued the plasma membrane expression of both human and mouse F508del-CFTR. Interestingly, the CFTR potentiator genistein enhanced CFTR-mediated iodide efflux from CHO cells expressing either human or mouse F508del-CFTR, whereas it only potentiated human F508del-CFTR Cl- channels in cell-free membrane patches, suggesting that its action on mouse F508del-CFTR is indirect. Thus, the F508del mutation has distinct effects on human and mouse CFTR Cl- channels.
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Affiliation(s)
- Samuel J Bose
- School of Physiology, Pharmacology and Neuroscience, University of Bristol , Bristol , United Kingdom
| | - Marcel J C Bijvelds
- Department of Gastroenterology and Hepatology, Erasmus University Medical Center , Rotterdam , The Netherlands
| | - Yiting Wang
- School of Physiology, Pharmacology and Neuroscience, University of Bristol , Bristol , United Kingdom
| | - Jia Liu
- School of Physiology, Pharmacology and Neuroscience, University of Bristol , Bristol , United Kingdom
| | - Zhiwei Cai
- School of Physiology, Pharmacology and Neuroscience, University of Bristol , Bristol , United Kingdom
| | - Alice G M Bot
- Department of Gastroenterology and Hepatology, Erasmus University Medical Center , Rotterdam , The Netherlands
| | - Hugo R de Jonge
- Department of Gastroenterology and Hepatology, Erasmus University Medical Center , Rotterdam , The Netherlands
| | - David N Sheppard
- School of Physiology, Pharmacology and Neuroscience, University of Bristol , Bristol , United Kingdom
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7
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Wang Y, Cai Z, Gosling M, Sheppard DN. Potentiation of the cystic fibrosis transmembrane conductance regulator Cl− channel by ivacaftor is temperature independent. Am J Physiol Lung Cell Mol Physiol 2018; 315:L846-L857. [DOI: 10.1152/ajplung.00235.2018] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Ivacaftor is the first drug to target directly defects in the cystic fibrosis transmembrane conductance regulator (CFTR), which causes cystic fibrosis (CF). To understand better how ivacaftor potentiates CFTR channel gating, here we investigated the effects of temperature on its action. As a control, we studied the benzimidazolone UCCF-853, which potentiates CFTR by a different mechanism. Using the patch-clamp technique and cells expressing recombinant CFTR, we studied the single-channel behavior of wild-type and F508del-CFTR, the most common CF mutation. Raising the temperature of the intracellular solution from 23 to 37°C increased the frequency but reduced the duration of wild-type and F508del-CFTR channel openings. Although the open probability ( Po) of wild-type CFTR increased progressively as temperature was elevated, the relationship between Po and temperature for F508del-CFTR was bell-shaped with a maximum Po at ~30°C. For wild-type CFTR and to a greatly reduced extent F508del-CFTR, the temperature dependence of channel gating was asymmetric with the opening rate demonstrating greater temperature sensitivity than the closing rate. At all temperatures tested, ivacaftor and UCCF-853 potentiated wild-type and F508del-CFTR. Strikingly, ivacaftor but not UCCF-853 abolished the asymmetric temperature dependence of CFTR channel gating. At all temperatures tested, Po values of wild-type CFTR in the presence of ivacaftor were approximately double those of F508del-CFTR, which were equivalent to or greater than those of wild-type CFTR at 37°C in the absence of the drug. We conclude that the principal effect of ivacaftor is to promote channel opening to abolish the temperature dependence of CFTR channel gating.
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Affiliation(s)
- Yiting Wang
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Biomedical Sciences Building, University Walk, Bristol, United Kingdom
| | - Zhiwei Cai
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Biomedical Sciences Building, University Walk, Bristol, United Kingdom
| | - Martin Gosling
- Enterprise Therapeutics, Sussex Innovation Centre, University of Sussex, Science Park Square, Brighton, United Kingdom
- Sussex Drug Discovery Centre, School of Life Sciences, University of Sussex, Brighton, United Kingdom
| | - David N. Sheppard
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Biomedical Sciences Building, University Walk, Bristol, United Kingdom
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8
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Dechecchi MC, Tamanini A, Cabrini G. Molecular basis of cystic fibrosis: from bench to bedside. ANNALS OF TRANSLATIONAL MEDICINE 2018; 6:334. [PMID: 30306073 PMCID: PMC6174194 DOI: 10.21037/atm.2018.06.48] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2018] [Accepted: 06/26/2018] [Indexed: 12/21/2022]
Abstract
Cystic fibrosis (CF), is an autosomal recessive disease affecting different organs. The lung disease, characterized by recurrent and chronic bacterial infection and inflammation since infancy, is the main cause of morbidity and precocious mortality of these individuals. The innovative therapies directed to repair the defective CF gene should account for the presence of more than 200 disease-causing mutations of the CF transmembrane conductance regulator (CFTR) gene. The review will recall the different experimental approaches in discovering CFTR protein targeted molecules, such as the high throughput screening on chemical libraries to discover correctors and potentiators of CFTR protein, dual-acting compounds, read-through molecules, splicing defects repairing tools, CFTR "amplifiers".
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Affiliation(s)
- Maria Cristina Dechecchi
- Laboratory of Analysis, Section of Molecular Pathology, University Hospital of Verona, Verona, Italy
| | - Anna Tamanini
- Laboratory of Analysis, Section of Molecular Pathology, University Hospital of Verona, Verona, Italy
| | - Giulio Cabrini
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
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9
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Cho DY, Zhang S, Lazrak A, Grayson JW, Peña Garcia JA, Skinner DF, Lim DJ, Mackey C, Banks C, Matalon S, Woodworth BA. Resveratrol and ivacaftor are additive G551D CFTR-channel potentiators: therapeutic implications for cystic fibrosis sinus disease. Int Forum Allergy Rhinol 2018; 9:100-105. [PMID: 30152192 DOI: 10.1002/alr.22202] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2018] [Revised: 06/19/2018] [Accepted: 07/15/2018] [Indexed: 01/04/2023]
Abstract
BACKGROUND Mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene result in defective Cl- transport and cause chronic bacterial infections in the upper and lower airways of cystic fibrosis (CF) patients. Ivacaftor is a CFTR potentiator that improves Cl- transport in CF patients with at least 1 copy of the G551D mutation. Resveratrol is also a potent CFTR potentiator that increases determinants of mucociliary transport. The objective of this study is to determine whether resveratrol and ivacaftor improve Cl- secretion in G551D CFTR over either agent alone. METHODS Fisher rat thyroid cells (FRT) transfected with G551D CFTR and human sinonasal epithelial cells (HSNE) containing the CFTR G551D mutation were subjected to pharmacologic manipulation of transepithelial ion transport in Ussing chambers. Activity was further evaluated using whole-cell patch clamp methods in G551D FRT cells. RESULTS In G551D FRT cells, resveratrol (100 μM) and ivacaftor (10 μM) significantly increased Cl- transport (change in short-circuit current, δISC = μA/cm2 ) compared with single-agent and dimethylsulfoxide vehicle controls (resveratrol + ivacaftor 4.97 ± 0.57 vs ivacaftor 0.74 ± 0.12 vs resveratrol 2.96 ± 0.52 vs control 0.74 ± 0.12; p < 0.001). Maximal Cl- secretion (20 μM forskolin) was also significantly enhanced (p < 0.0001). Activity was confirmed in G551D HSNE (resveratrol + ivacaftor 4.48 ± 0.39 vs ivacaftor 1.05 ± 0.11 vs. resveratrol 0.84 ± 0.3 vs control, 0.0 ± 0.02; p < 0.001), and whole-cell patch clamp analysis in G551D FRT cells (resveratrol + ivacaftor -2535 ± 179.3 pA vs ivacaftor -1408.9 ± 101.3 pA vs resveratrol; -766.2 ± 71.2 pA; p < 0.0001). CONCLUSION Additive improvement in G551D CFTR-mediated Cl- secretion suggests that resveratrol could enhance ivacaftor therapy in these patients and improve CF-related rhinosinusitis.
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Affiliation(s)
- Do-Yeon Cho
- Department of Otolaryngology, University of Alabama at Birmingham, Birmingham, AL.,Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama at Birmingham, Birmingham, AL
| | - Shaoyan Zhang
- Department of Otolaryngology, University of Alabama at Birmingham, Birmingham, AL.,Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama at Birmingham, Birmingham, AL
| | - Ahmed Lazrak
- Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama at Birmingham, Birmingham, AL.,Department of Anesthesiology and Perioperative Medicine, University of Alabama at Birmingham, Birmingham, AL
| | - Jessica W Grayson
- Department of Otolaryngology, University of Alabama at Birmingham, Birmingham, AL
| | - Jaime A Peña Garcia
- Department of Otolaryngology, University of Alabama at Birmingham, Birmingham, AL
| | - Daniel F Skinner
- Department of Otolaryngology, University of Alabama at Birmingham, Birmingham, AL.,Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama at Birmingham, Birmingham, AL
| | - Dong Jin Lim
- Department of Otolaryngology, University of Alabama at Birmingham, Birmingham, AL.,Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama at Birmingham, Birmingham, AL
| | - Calvin Mackey
- Department of Otolaryngology, University of Alabama at Birmingham, Birmingham, AL.,Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama at Birmingham, Birmingham, AL
| | - Catherine Banks
- Department of Otolaryngology, University of Alabama at Birmingham, Birmingham, AL
| | - Sadis Matalon
- Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama at Birmingham, Birmingham, AL.,Department of Anesthesiology and Perioperative Medicine, University of Alabama at Birmingham, Birmingham, AL
| | - Bradford A Woodworth
- Department of Otolaryngology, University of Alabama at Birmingham, Birmingham, AL.,Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama at Birmingham, Birmingham, AL
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10
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Han ST, Rab A, Pellicore MJ, Davis EF, McCague AF, Evans TA, Joynt AT, Lu Z, Cai Z, Raraigh KS, Hong JS, Sheppard DN, Sorscher EJ, Cutting GR. Residual function of cystic fibrosis mutants predicts response to small molecule CFTR modulators. JCI Insight 2018; 3:121159. [PMID: 30046002 DOI: 10.1172/jci.insight.121159] [Citation(s) in RCA: 70] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2018] [Accepted: 06/12/2018] [Indexed: 12/24/2022] Open
Abstract
Treatment of individuals with cystic fibrosis (CF) has been transformed by small molecule therapies that target select pathogenic variants in the CF transmembrane conductance regulator (CFTR). To expand treatment eligibility, we stably expressed 43 rare missense CFTR variants associated with moderate CF from a single site in the genome of human CF bronchial epithelial (CFBE41o-) cells. The magnitude of drug response was highly correlated with residual CFTR function for the potentiator ivacaftor, the corrector lumacaftor, and ivacaftor-lumacaftor combination therapy. Response of a second set of 16 variants expressed stably in Fischer rat thyroid (FRT) cells showed nearly identical correlations. Subsets of variants were identified that demonstrated statistically significantly higher responses to specific treatments. Furthermore, nearly all variants studied in CFBE cells (40 of 43) and FRT cells (13 of 16) demonstrated greater response to ivacaftor-lumacaftor combination therapy than either modulator alone. Together, these variants represent 87% of individuals in the CFTR2 database with at least 1 missense variant. Thus, our results indicate that most individuals with CF carrying missense variants are (a) likely to respond modestly to currently available modulator therapy, while a small fraction will have pronounced responses, and (b) likely to derive the greatest benefit from combination therapy.
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Affiliation(s)
- Sangwoo T Han
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Andras Rab
- Department of Pediatrics, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Matthew J Pellicore
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Emily F Davis
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Allison F McCague
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Taylor A Evans
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Anya T Joynt
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Zhongzhou Lu
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Zhiwei Cai
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, United Kingdom
| | - Karen S Raraigh
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Jeong S Hong
- Department of Pediatrics, Emory University School of Medicine, Atlanta, Georgia, USA
| | - David N Sheppard
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, United Kingdom
| | - Eric J Sorscher
- Department of Pediatrics, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Garry R Cutting
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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Spielberg DR, Clancy JP. Cystic Fibrosis and Its Management Through Established and Emerging Therapies. Annu Rev Genomics Hum Genet 2016; 17:155-75. [PMID: 26905785 DOI: 10.1146/annurev-genom-090314-050024] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Cystic fibrosis (CF) is the most common life-shortening autosomal recessive disorder in the Caucasian population and occurs in many other ethnicities worldwide. The daily treatment burden is substantial for CF patients even when they are well, with numerous pharmacologic and physical therapies targeting lung disease requiring the greatest time commitment. CF treatments continue to advance with greater understanding of factors influencing long-term morbidity and mortality. In recent years, in-depth understanding of genetic and protein structure-function relationships has led to the introduction of targeted therapies for patients with specific CF genotypes. With these advances, CF has become a model of personalized or precision medicine. The near future will see greater access to targeted therapies for most patients carrying common mutations, which will mandate individualized bench-to-bedside methodologies for those with rare genotypes.
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Affiliation(s)
- David R Spielberg
- Department of Pediatrics, Division of Pulmonary Medicine, Cincinnati Children's Hospital Medical Center and University of Cincinnati, Cincinnati, Ohio 45229; ,
| | - John P Clancy
- Department of Pediatrics, Division of Pulmonary Medicine, Cincinnati Children's Hospital Medical Center and University of Cincinnati, Cincinnati, Ohio 45229; ,
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Woodworth BA. Resveratrol ameliorates abnormalities of fluid and electrolyte secretion in a hypoxia-Induced model of acquired CFTR deficiency. Laryngoscope 2015; 125 Suppl 7:S1-S13. [PMID: 25946147 DOI: 10.1002/lary.25335] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2015] [Accepted: 03/24/2015] [Indexed: 01/25/2023]
Abstract
OBJECTIVE/HYPOTHESIS Ineffective mucociliary clearance (MCC) is a common pathophysiologic process that underlies airway inflammation and infection. A dominant fluid and electrolyte secretory pathway in the nasal airways is governed by the cystic fibrosis transmembrane conductance regulator (CFTR). Decreased transepithelial Cl(-) transport secondary to an acquired CFTR deficiency may exacerbate respiratory epithelial dysfunction by diminishing MCC and increasing mucus viscosity. The objectives of the present study are to 1) develop a model of acquired CFTR deficiency in sinonasal epithelium using hypoxia, 2) investigate whether the polyphenol resveratrol promotes CFTR-mediated anion transport, 3) explore resveratrol mechanism of action and determine therapeutic suitability for overcoming acquired CFTR defects, and 4) test the drug in the hypoxic model of acquired CFTR deficiency in preparation for a clinical trial in human sinus disease. We hypothesize that hypoxia will induce depletion of airway surface liquid (ASL) secondary to acquired CFTR deficiency and that resveratrol will restore transepithelial Cl(-) secretion and recover ASL hydration. STUDY DESIGN Basic science. METHODS Murine nasal septal (MNSE) and human sinonasal epithelial (HSNE) cultures were incubated under hypoxic conditions (1% O2 , 5% CO2 ) and transepithelial ion transport (change in short-circuit current = ΔISC ) evaluated in Ussing chambers. Resveratrol was tested using primary cells and HEK293 cells expressing human CFTR by Ussing chamber and patch clamp techniques under both phosphorylating and nonphosphorylating conditions. CFTR activation was evaluated in human explants and by murine in vivo (nasal potential difference) assessment. Cellular cyclic adenosine monophosphate (cAMP) (ELISA) and subsequent CFTR regulatory domain (R-D) phosphorylation (gel-shift assay) were also evaluated. Effects of hypoxia and resveratrol on ASL were tested using confocal laser scanning microscopy (CLSM) and micro-optical coherence tomography (µOCT). RESULTS Hypoxia significantly decreased ΔISC (in µA/cm(2) ) attributable to CFTR at 12 and 24 hours of exposure in both MNSE (13.55 ± 0.46 [12 hours]; 12.75 ± 0.07 [24 hours] vs. 19.23 ± 0.18 [control]; P < 0.05) and HSNE (19.55 ± 0.56 [12 hours]; 17.67 ± 1.13 [24 hours] vs. 25.49 ± 1.48 [control]; P < 0.05). We have shown that resveratrol (100 μM) enhanced CFTR-dependent Cl(-) secretion in HSNE to an extent comparable to the recently Food and Drug Administration-approved CFTR potentiator, ivacaftor. Cl(-) transport across human sinonasal explants (78.42 ± 1.75 vs. 1.75 ± 1.5 [control]; P < 0.05) and in vivo murine nasal epithelium (-4 ± 1.8 vs. -0.8 ± 1.7 mV [control]; P < 0.05) were also significantly increased by the drug. No increase in cAMP or CFTR R-D phosphorylation was detected. Inside-out patches showed increased CFTR open probability (NPo/N (N = channel number]) compared to controls in both MNSE (0.329 ± 0.116 vs. 0.119 ± 0.059 [control]; P < 0.05) and HEK293 cells (0.22 ± 0.048 vs. 0.125 ± 0.07 [control]; P < 0.05). ASL thickness was decreased under hypoxic conditions when measured by CLSM (4.19 ± 0.44 vs. 6.88 ± 0.67 [control]; P < 0.05). A 30-minute apical application of resveratrol increased ASL depth in normal epithelium (8.08 ± 1.68 vs. 6.11 ± 0.47 [control]; P < 0.05). Furthermore, hypoxia-induced abnormalities of fluid and electrolyte secretion in sinonasal epithelium were restored with resveratrol treatment (5.55 ± 0.74 vs. 3.13 ± 0.17 [control]; P < 0.05). CONCLUSIONS CFTR activation with a leading edge Cl(-) secretagogue such as resveratrol represents an innovative approach to overcoming acquired CFTR defects in sinus and nasal airway disease. This exciting new strategy bears further testing in non-CF individuals with chronic rhinosinusitis. LEVEL OF EVIDENCE N/A. Laryngoscope, 125:S1-S13, 2015.
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Affiliation(s)
- Bradford A Woodworth
- Department of Otolaryngology-Head and Neck Surgery, University of Alabama at Birmingham, Birmingham, Alabama, U.S.A
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Wang Y, Liu J, Loizidou A, Bugeja LA, Warner R, Hawley BR, Cai Z, Toye AM, Sheppard DN, Li H. CFTR potentiators partially restore channel function to A561E-CFTR, a cystic fibrosis mutant with a similar mechanism of dysfunction as F508del-CFTR. Br J Pharmacol 2014; 171:4490-503. [PMID: 24902474 DOI: 10.1111/bph.12791] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2013] [Revised: 04/22/2014] [Accepted: 05/24/2014] [Indexed: 01/13/2023] Open
Abstract
BACKGROUND AND PURPOSE Dysfunction of the cystic fibrosis transmembrane conductance regulator (CFTR) Cl(-) channel causes the genetic disease cystic fibrosis (CF). Towards the development of transformational drug therapies for CF, we investigated the channel function and action of CFTR potentiators on A561E, a CF mutation found frequently in Portugal. Like the most common CF mutation F508del, A561E causes a temperature-sensitive folding defect that prevents CFTR delivery to the cell membrane and is associated with severe disease. EXPERIMENTAL APPROACH Using baby hamster kidney cells expressing recombinant CFTR, we investigated CFTR expression by cell surface biotinylation, and function and pharmacology with the iodide efflux and patch-clamp techniques. KEY RESULTS Low temperature incubation delivered a small proportion of A561E-CFTR protein to the cell surface. Like F508del-CFTR, low temperature-rescued A561E-CFTR exhibited a severe gating defect characterized by brief channel openings separated by prolonged channel closures. A561E-CFTR also exhibited thermoinstability, losing function more quickly than F508del-CFTR in cell-free membrane patches and intact cells. Using the iodide efflux assay, CFTR potentiators, including genistein and the clinically approved small-molecule ivacaftor, partially restored function to A561E-CFTR. Interestingly, ivacaftor restored wild-type levels of channel activity (as measured by open probability) to single A561E- and F508del-CFTR Cl(-) channels. However, it accentuated the thermoinstability of both mutants in cell-free membrane patches. CONCLUSIONS AND IMPLICATIONS Like F508del-CFTR, A561E-CFTR perturbs protein processing, thermostability and channel gating. CFTR potentiators partially restore channel function to low temperature-rescued A561E-CFTR. Transformational drug therapy for A561E-CFTR is likely to require CFTR correctors, CFTR potentiators and special attention to thermostability.
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Affiliation(s)
- Yiting Wang
- School of Physiology and Pharmacology, University of Bristol, Bristol, UK
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14
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Gianotti A, Melani R, Caci E, Sondo E, Ravazzolo R, Galietta LJV, Zegarra-Moran O. Epithelial sodium channel silencing as a strategy to correct the airway surface fluid deficit in cystic fibrosis. Am J Respir Cell Mol Biol 2013; 49:445-52. [PMID: 23600628 DOI: 10.1165/rcmb.2012-0408oc] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
In the respiratory system, Na(+) absorption and Cl(-) secretion are balanced to maintain an appropriate airway surface fluid (ASF) volume and ensure efficient mucociliary clearance. In cystic fibrosis (CF), this equilibrium is disrupted by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene, resulting in the absence of functional CFTR-dependent Cl(-) secretion. The consequences of defective Cl(-) transport are worsened by the persistence of Na(+) absorption, which contributes to airway surface dehydration. We asked whether normal ASF can be restored to an equal extent by recovering Cl(-) secretion from mutated CFTR or by reducing Na(+) absorption. This is highly relevant in the selection of the best strategy for the treatment of patients with CF. We analyzed the ASF thickness of primary cultured bronchial CF and non-CF epithelia after silencing the epithelial Na(+) channel (ENaC) with specific short, interfering RNAs (siRNAs) and after the pharmacological stimulation of CFTR. Our results indicate that (1) single siRNAs complementary to ENaC subunits are sufficient to reduce ENaC transcripts, Na(+) channel activity, and fluid transport, but only silencing both the α and β ENaC subunits at the same time leads to an increase of ASF (from nearly 7 µm to more than 9 µm); (2) the ASF thickness obtained in this way is about half that measured after maximal CFTR stimulation in non-CF epithelia (10-14 µm); and (3) the pharmacological rescue of mutant CFTR increases the ASF to the same extent as ENaC silencing. Our results indicate that CFTR rescue and ENaC silencing both produce a significant and long-lasting increase of airway hydration in vitro.
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Affiliation(s)
- Ambra Gianotti
- Laboratorio di Genetica Molecolare, Istituto Giannina Gaslini, Largo G. Gaslini 5, Genoa, Italy
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Namkung W, Park J, Seo Y, Verkman AS. Novel amino-carbonitrile-pyrazole identified in a small molecule screen activates wild-type and ΔF508 cystic fibrosis transmembrane conductance regulator in the absence of a cAMP agonist. Mol Pharmacol 2013; 84:384-92. [PMID: 23788656 DOI: 10.1124/mol.113.086348] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Cystic fibrosis (CF) is caused by loss-of-function mutations in the CF transmembrane conductance regulator (CFTR) Cl⁻ channel. We developed a phenotype-based high-throughput screen to identify small-molecule activators of human airway epithelial Ca²⁺-activated Cl⁻ channels (CaCCs) for CF therapy. Unexpectedly, screening of ∼110,000 synthetic small molecules revealed an amino-carbonitrile-pyrazole, C(act)-A1, that activated CFTR but not CaCC Cl⁻ conductance. C(act)-A1 produced large and sustained CFTR Cl⁻ currents in CFTR-expressing Fisher rat thyroid (FRT) cells and in primary cultures of human bronchial epithelial (HBE) cells, without increasing intracellular cAMP and in the absence of a cAMP agonist. C(act)-A1 produced linear whole-cell currents. C(act)-A1 also activated ΔF508-CFTR Cl⁻ currents in low temperature-rescued ΔF508-CFTR-expressing FRT cells and CF-HBE cells (from homozygous ΔF508 patients) in the absence of a cAMP agonist, and showed additive effects with forskolin. In contrast, N-(2,4-di-tert-butyl-5-hydroxyphenyl)-4-oxo-1,4-dihydroquinoline-3-carboxamide (VX-770) and genistein produced little or no ΔF508-CFTR Cl⁻ current in the absence of a cAMP agonist. In FRT cells expressing G551D-CFTR and in CF nasal polyp epithelial cells (from a heterozygous G551D/Y1092X-CFTR patient), C(act)-A1 produced little Cl⁻ current by itself but showed synergy with forskolin. The amino-carbonitrile-pyrazole C(act)-A1 identified here is unique among prior CFTR-activating compounds, as it strongly activated wild-type and ΔF508-CFTR in the absence of a cAMP agonist. Increasing ΔF508-CFTR Cl⁻ conductance by an "activator," as defined by activation in the absence of cAMP stimulation, provides a novel strategy for CF therapy that is different from that of a "potentiator," which requires cAMP elevation.
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Affiliation(s)
- Wan Namkung
- College of Pharmacy, Yonsei Institute of Pharmaceutical Sciences, Yonsei University, Incheon 406-840, Korea.
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16
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Galfrè E, Galeno L, Moran O. A potentiator induces conformational changes on the recombinant CFTR nucleotide binding domains in solution. Cell Mol Life Sci 2012; 69:3701-13. [PMID: 22752155 PMCID: PMC11114511 DOI: 10.1007/s00018-012-1049-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2012] [Revised: 05/14/2012] [Accepted: 05/30/2012] [Indexed: 01/23/2023]
Abstract
Nucleotide binding domains (NBD1 and NBD2) of the cystic fibrosis transmembrane conductance regulator (CFTR), the defective protein in cystic fibrosis, are responsible for controlling the gating of the chloride channel and are the putative binding sites for several candidate drugs in the disease treatment. We studied the effects of the application of 2-pyrimidin-7,8-benzoflavone (PBF), a strong potentiator of the CFTR, on the properties of recombinant and equimolar NBD1/NBD2 mixture in solution. The results indicate that the potentiator induces significant conformational changes of the NBD1/NBD2 dimer in solution. The potentiator does not modify the ATP binding constant, but reduces the ATP hydrolysis activity of the NBD1/NBD2 mixture. The intrinsic fluorescence and the guanidinium denaturation measurements indicate that the potentiator induces different conformational changes on the NBD1/NBD2 mixture in the presence and absence of ATP. It was confirmed from small-angle X-ray scattering experiments that, in absence of ATP, the NBD1/NBD2 dimer was disrupted by the potentiator, but in the presence of 2 mM ATP, the two NBDs kept dimerised, and a major change in the size and the shape of the structure was observed. We propose that these conformational changes could modify the NBDs-intracellular loop interaction in a way that would facilitate the open state of the channel.
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Affiliation(s)
- Elena Galfrè
- Istituto di Biofisica, Consiglio Nazionale delle Ricerche, Via De Marini, 6, 16149 Genoa, Italy
| | - Lauretta Galeno
- Istituto di Biofisica, Consiglio Nazionale delle Ricerche, Via De Marini, 6, 16149 Genoa, Italy
| | - Oscar Moran
- Istituto di Biofisica, Consiglio Nazionale delle Ricerche, Via De Marini, 6, 16149 Genoa, Italy
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17
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Pawlikowska-Pawlęga B, Misiak LE, Zarzyka B, Paduch R, Gawron A, Gruszecki WI. FTIR, (1)H NMR and EPR spectroscopy studies on the interaction of flavone apigenin with dipalmitoylphosphatidylcholine liposomes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2012; 1828:518-27. [PMID: 23088916 DOI: 10.1016/j.bbamem.2012.10.013] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2012] [Revised: 09/27/2012] [Accepted: 10/15/2012] [Indexed: 11/25/2022]
Abstract
Apigenin (5,7,4'-trihydroxyflavone) is a cancer chemopreventive agent and a member of the family of plant flavonoids. Apigenin interaction with liposomes formed with dipalmitoylphosphatidylcholine (DPPC) was investigated by means of FTIR spectroscopy, (1)H NMR and EPR techniques. Fluorescent microscopy and electron microscopy were applied to study the apigenin effects on colon myofibroblasts and human skin fibroblasts. The strong rigidifying effect of apigenin with respect to polar head groups was concluded on the basis of the action of the flavone on partition coefficient of Tempo spin label between the water and lipid phases. The ordering effect was also found in hydrophobic region at the depth monitored by 5-SASL and 16-SASL spin labels. The inclusion of apigenin to the membrane restricted the motional freedom of polar head groups lowering penetration of Pr(3+) ions to the membranes. The (1)H NMR technique supported also the restriction of motional freedom of the membrane in the hydrophobic region, especially in the zone of CH(2) groups of alkyl chains. FTIR analysis showed that apigenin incorporates into DPPC liposomes via hydrogen bonding between its own hydroxyl groups and lipid polar head groups in the C-O-P-O-C segment. It is also very likely that hydroxyl groups of apigenin link with polar groups of DPPC by water bridges. Electron and fluorescence microscopic observations revealed changes in the internal membrane organization of the examined cells. In conclusion, the changes of the structural and dynamic properties of membranes can be crucial for processes involving tumor suppression signal transduction pathways and cell cycle regulation.
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Affiliation(s)
- Bożena Pawlikowska-Pawlęga
- Department of Comparative Anatomy and Anthropology, Maria Curie-Skłodowska University, Akademicka 19, 20-033 Lublin, Poland.
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18
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Laube M, Kimpel SU, Dietl P, Thome UH, Wittekindt OH. Benzimidazolones enhance the function of epithelial Na⁺ transport. Br J Pharmacol 2012; 168:1329-40. [PMID: 23083067 DOI: 10.1111/bph.12027] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2011] [Revised: 09/11/2012] [Accepted: 09/18/2012] [Indexed: 01/11/2023] Open
Abstract
BACKGROUND AND PURPOSE Pharmacological enhancement of vectorial Na⁺ transport may be useful to increase alveolar fluid clearance. Herein, we investigated the influence of the benzimidazolones 1-ethyl-1,3-dihydro-2-benzimidazolone (1-EBIO), 5,6-dichloro-1-EBIO (DC-EBIO) and chlorzoxazone on vectorial epithelial Na⁺ transport. EXPERIMENTAL APPROACH Effects on vectorial Na⁺ transport and amiloride-sensitive apical membrane Na⁺ permeability were determined by measuring short-circuit currents (I(SC)) in rat fetal distal lung epithelial (FDLE) monolayers. Furthermore, amiloride-sensitive membrane conductance and the open probability of epithelial Na⁺ channels (ENaC) were determined by patch clamp experiments using A549 cells. KEY RESULTS I(SC) was increased by approximately 50% after addition of 1-EBIO, DC-EBIO and chlorzoxazone. With permeabilized basolateral membranes in the presence of a 145:5 apical to basolateral Na⁺ gradient, the benzimidazolones markedly increased amiloride-sensitive I(SC). 5-(N-Ethyl-N-isopropyl)amiloride-induced inhibition of I(SC) was not affected. The benzamil-sensitive I(SC) was increased in benzimidazolone-stimulated monolayers. Pretreating the apical membrane with amiloride, which inhibits ENaC, completely prevented the stimulating effects of benzimidazolones on I(SC). Furthermore, 1-EBIO (1 mM) and DC-EBIO (0.1 mM) significantly increased (threefold) the open probability of ENaC without influencing current amplitude. Whole cell measurements showed that DC-EBIO (0.1 mM) induced an amiloride-sensitive increase in membrane conductance. CONCLUSION AND IMPLICATIONS Benzimidazolones have a stimulating effect on vectorial Na⁺ transport. The antagonist sensitivity of this effect suggests the benzimidazolones elicit this action by activating the highly selective ENaC currents. Thus, the results demonstrate a possible new strategy for directly enhancing epithelial Na⁺ transport.
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Affiliation(s)
- M Laube
- Division of Neonatology, University of Leipzig, Leipzig, Germany
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19
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Roomans GM. Pharmacological Approaches to Correcting the Ion Transport Defect in Cystic Fibrosis. ACTA ACUST UNITED AC 2012; 2:413-31. [PMID: 14719993 DOI: 10.1007/bf03256668] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Cystic fibrosis (CF) is a lethal genetic disease caused by a mutation in a membrane protein, the cystic fibrosis transmembrane conductance regulator (CFTR), which mainly (but not exclusively) functions as a chloride channel. The main clinical symptoms are chronic obstructive lung disease, which is responsible for most of the morbidity and mortality associated with CF, and pancreatic insufficiency. About 1000 mutations of the gene coding for CFTR are currently known; the most common of these, present in the great majority of the patients (Delta508) results in the deletion of a phenylalanine at position 508. In this mutation, the aberrant CFTR is not transported to the membrane but degraded in the ubiquitin-proteasome pathway. The aim of this review is to give an overview of the pharmacologic strategies currently used in attempts to overcome the ion transport defect in CF. One strategy to develop pharmacologic treatment for CF is to inhibit the breakdown of DeltaF508-CFTR by interfering with the chaperones involved in the folding of CFTR. At least in in vitro systems, this can be accomplished by sodium phenylbutyrate, or S-nitrosoglutathione (GSNO), and also by genistein or benzo[c]quinolizinium compounds. It is also possible to stimulate CFTR or its mutated forms, when present in the plasma membrane, using xanthines, genistein, and various other compounds, such as benzamidizoles and benzoxazoles, benzo[c]quinolizinium compounds or phenantrolines. Experimental results are not always unambiguous, and adverse effects have been incompletely tested. Some clinical tests have been done on sodium phenyl butyrate, GSNO and genistein, mostly in respect to other diseases, and the results demonstrate that these drugs are reasonably well tolerated. Their efficiency in the treatment of CF has not yet been demonstrated, however. An alternative strategy is to compensate for the defective chloride transport by CFTR by stimulation of other chloride channels. This can be done via purinergic receptors. A phase I study using a stable uridine triphosphate analog has recently been completed. A second alternative strategy is to attempt to maintain hydration of the airway mucus by inhibiting Na(+) uptake by the epithelial Na(+) channel using amiloride or stable analogs of amiloride. Clinical tests so far have been inconclusive. A number of other suggestions are currently being explored. The minority of patients with CF who have a stop mutation may benefit from treatment with gentamicin. The difficulties in finding a pharmacologic treatment for CF may be due to the fact that CFTR has additional functions besides chloride transport, and interfering with CFTR biosynthesis or activation implies interference with central cellular processes, which may have undesirable adverse effects.
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Affiliation(s)
- Godfried M Roomans
- Department of Medical Cell Biology, University of Uppsala, Uppsala, Sweden.
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Abstract
With knowledge of the molecular behaviour of the cystic fibrosis transmembrane conductance regulator (CFTR), its physiological role and dysfunction in cystic fibrosis (CF), therapeutic strategies are now being developed that target the root cause of CF rather than disease symptoms. Here, we review progress towards the development of rational new therapies for CF. We highlight the discovery of small molecules that rescue the cell surface expression and defective channel gating of CF mutants, termed CFTR correctors and CFTR potentiators, respectively. We draw attention to alternative approaches to restore epithelial ion transport to CF epithelia, including inhibitors of the epithelial Na(+) channel (ENaC) and activators of the Ca(2+)-activated Cl(-) channel TMEM16A. The expertise required to translate small molecules identified in the laboratory to drugs for CF patients depends on our ability to coordinate drug development at an international level and our ability to provide pertinent biological information using suitable disease models.
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Dannhoffer L, Billet A, Jollivet M, Melin-Heschel P, Faveau C, Becq F. Stimulation of Wild-Type, F508del- and G551D-CFTR Chloride Channels by Non-Toxic Modified pyrrolo[2,3-b]pyrazine Derivatives. Front Pharmacol 2011; 2:48. [PMID: 21897819 PMCID: PMC3159890 DOI: 10.3389/fphar.2011.00048] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2011] [Accepted: 08/03/2011] [Indexed: 11/17/2022] Open
Abstract
Cystic fibrosis (CF) is a major inherited disorder involving abnormalities of fluid and electrolyte transport in a number of different organs due to abnormal function of cystic fibrosis transmembrane conductance regulator (CFTR) protein. We recently identified a family of CFTR activators, which contains the hit: RP107 [7-n-butyl-6-(4-hydroxyphenyl)[5H]-pyrrolo[2,3-b]pyrazine]. Here, we further evaluated the effect of the chemical modifications of the RP107-OH radical on CFTR activation. The replacement of the OH radical by a fluorine atom at position 2 (RP193) or 4 (RP185) significantly decreased the toxicity of the compounds without altering the ability to activate CFTR, especially for RP193. The non-toxic compound RP193 has no effect on cAMP production but stimulates the channel activity of wild-type CFTR in stably transfected CHO cells, in human bronchial epithelial NuLi-1 cells, and in primary culture of human bronchial epithelial cells (HBEC). Whole-cell and single patch-clamp recordings showed that RP193 induced a linear, time- and voltage-independent current, which was fully inhibited by two different and selective CFTR inhibitors (CFTRinh-172 and GPinh5a). Moreover, RP193 stimulates CFTR in temperature-rescued CuFi-1 (F508del/F508del) HBEC and in CHO cells stably expressing G551D-CFTR. This study shows that it is feasible to reduce cytotoxicity of chemical compounds without affecting their potency to activate CFTR and to rescue the class 2 F508del-CFTR and class 3 G551D-CFTR CF mutant activities.
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Affiliation(s)
- Luc Dannhoffer
- Institut de Physiologie et Biologie Cellulaires, UMR 6187, Université de Poitiers CNRS, Poitiers, France
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Sondo E, Tomati V, Caci E, Esposito AI, Pfeffer U, Pedemonte N, Galietta LJV. Rescue of the mutant CFTR chloride channel by pharmacological correctors and low temperature analyzed by gene expression profiling. Am J Physiol Cell Physiol 2011; 301:C872-85. [PMID: 21753184 DOI: 10.1152/ajpcell.00507.2010] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The F508del mutation, the most frequent in cystic fibrosis (CF), impairs the maturation of the CFTR chloride channel. The F508del defect can be partially overcome at low temperature (27°C) or with pharmacological correctors. However, the efficacy of correctors on the mutant protein appears to be dependent on the cell expression system. We have used a bronchial epithelial cell line, CFBE41o-, to determine the efficacy of various known treatments and to discover new correctors. Compared with other cell types, CFBE41o- shows the largest response to low temperature and the lowest one to correctors such as corr-4a and VRT-325. A screening of a small-molecule library identified 9-aminoacridine and ciclopirox, which were significantly more effective than corr-4a and VRT-325. Analysis with microarrays revealed that 9-aminoacridine, ciclopirox, and low temperature, in contrast to corr-4a, cause a profound change in cell transcriptome. These data suggest that 9-aminoacridine and ciclopirox act on F508del-CFTR maturation as proteostasis regulators, a mechanism already proposed for the histone deacetylase inhibitor suberoylanilide hydroxamic acid (SAHA). However, we found that 9-aminoacridine, ciclopirox, and SAHA, in contrast to corr-4a, VRT-325, and low temperature, do not increase chloride secretion in primary bronchial epithelial cells from CF patients. These conflicting data appeared to be correlated with different gene expression signatures generated by these treatments in the cell line and in primary bronchial epithelial cells. Our results suggest that F508del-CFTR correctors acting by altering the cell transcriptome may be particularly active in heterologous expression systems but markedly less effective in native epithelial cells.
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Affiliation(s)
- Elvira Sondo
- Laboratory of Molecular Genetics, Istituto Giannina Gaslini, Genoa, Italy
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Pyle LC, Ehrhardt A, Mitchell LH, Fan L, Ren A, Naren AP, Li Y, Clancy JP, Bolger GB, Sorscher EJ, Rowe SM. Regulatory domain phosphorylation to distinguish the mechanistic basis underlying acute CFTR modulators. Am J Physiol Lung Cell Mol Physiol 2011; 301:L587-97. [PMID: 21724857 DOI: 10.1152/ajplung.00465.2010] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Modulator compounds intended to overcome disease-causing mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) show significant promise in clinical testing for cystic fibrosis. However, the mechanism(s) of action underlying these compounds are not fully understood. Activation of CFTR ion transport requires PKA-regulated phosphorylation of the regulatory domain (R-D) and dimerization of the nucleotide binding domains. Using a newly developed assay, we evaluated nine compounds including both CFTR potentatiators and activators discovered via various high-throughput screening strategies to acutely augment CFTR activity. We found considerable differences in the effects on R-D phosphorylation. Some (including UC(CF)-152) stimulated robust phosphorylation, and others had little effect (e.g., VRT-532 and VX-770). We then compared CFTR activation by UC(CF)-152 and VRT-532 in Ussing chamber studies using two epithelial models, CFBE41o(-) and Fischer rat thyroid cells, expressing various CFTR forms. UC(CF)-152 activated wild-type-, G551D-, and rescued F508del-CFTR currents but did not potentiate cAMP-mediated CFTR activation. In contrast, VRT-532 moderately activated CFTR short-circuit current and strongly potentiated forskolin-mediated current. Combined with the result that UC(CF)-152, but not VRT-532 or VX-770, acts by increasing CFTR R-D phosphorylation, these findings indicate that potentiation of endogenous cAMP-mediated activation of mutant CFTR is not due to a pathway involving augmented R-D phosphorylation. This study presents an assay useful to distinguish preclinical compounds by a crucial mechanism underlying CFTR activation, delineates two types of compound able to acutely augment CFTR activity (e.g., activators and potentiators), and demonstrates that a number of different mechanisms can be successfully employed to activate mutant CFTR.
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Affiliation(s)
- Louise C Pyle
- Departments of Genetics, University of Alabama at Birmingham, 35294-0006, USA
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Kelly-Aubert M, Trudel S, Fritsch J, Nguyen-Khoa T, Baudouin-Legros M, Moriceau S, Jeanson L, Djouadi F, Matar C, Conti M, Ollero M, Brouillard F, Edelman A. GSH monoethyl ester rescues mitochondrial defects in cystic fibrosis models. Hum Mol Genet 2011; 20:2745-59. [DOI: 10.1093/hmg/ddr173] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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25
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Yu YC, Miki H, Nakamura Y, Hanyuda A, Matsuzaki Y, Abe Y, Yasui M, Tanaka K, Hwang TC, Bompadre SG, Sohma Y. Curcumin and genistein additively potentiate G551D-CFTR. J Cyst Fibros 2011; 10:243-52. [PMID: 21441077 DOI: 10.1016/j.jcf.2011.03.001] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2010] [Revised: 02/19/2011] [Accepted: 03/01/2011] [Indexed: 12/20/2022]
Abstract
BACKGROUND The G551D mutation in the cystic fibrosis transmembrane conductance regulator (CFTR) is a common cause of cystic fibrosis (CF). G551D-CFTR is characterized by an extremely low open probability despite its normal trafficking to the plasma membrane. Numerous small molecules have been shown to increase the activity of G551D-CFTR presumably by binding to the CFTR protein. METHODS We investigated the effect of curcumin, genistein and their combined application on G551D-CFTR activity using the patch clamp technique. RESULTS Curcumin increased G551D-CFTR whole-cell and single-channel currents less than genistein did at their maximally effective concentrations. However, curcumin further increased the channel activity of G551D-CFTR that had been already maximally potentiated by genistein, up to ~50% of the WT-CFTR level. In addition, the combined application of genistein and curcumin over a lower concentration range synergistically rescued the gating defect of G551D-CFTR. CONCLUSIONS The additive effects between curcumin and genistein not only support the hypothesis that multiple mechanisms are involved in the action of CFTR potentiators, but also pose pharmaceutical implications in the development of drugs for CF pharmacotherapy.
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Affiliation(s)
- Ying-Chun Yu
- Department of Pharmacology, Keio University School of Medicine, Shinjuku, Tokyo 160-8582, Japan
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Noy E, Senderowitz H. Combating cystic fibrosis: in search for CF transmembrane conductance regulator (CFTR) modulators. ChemMedChem 2011; 6:243-51. [PMID: 21275046 DOI: 10.1002/cmdc.201000488] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2010] [Indexed: 11/05/2022]
Affiliation(s)
- Efrat Noy
- Department of Chemistry, Bar Ilan University, Ramat-Gan 52900, Israel
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Lin S, Sui J, Cotard S, Fung B, Andersen J, Zhu P, El Messadi N, Lehar J, Lee M, Staunton J. Identification of synergistic combinations of F508del cystic fibrosis transmembrane conductance regulator (CFTR) modulators. Assay Drug Dev Technol 2010; 8:669-84. [PMID: 21050065 DOI: 10.1089/adt.2010.0313] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Cystic fibrosis (CF) is an inherited, life-threatening disease caused by mutations in the gene encoding cystic fibrosis transmembrane conductance regulator (CFTR), an ABC transporter-class protein and ion channel that transports ions across epithelial cell membranes. The most common mutation leads to the deletion of a single phenylalanine, and the resulting protein, F508del-CFTR, shows reduced trafficking to the membrane and defective channel gating. The ideal therapeutic approach would address both of these defects and restore channel function at the same time. We describe here the application of a combination high-throughput screening to search for synergistic modulators of F508del-CFTR. With the adapted Fischer rat thyroid-yellow fluorescent protein halide flux assay to the combination high-throughput screening platform, we identified many interesting single agents as CFTR modulators from a library of approved drugs and mechanistic probe compounds, and combinations that synergistically modulate F508del-CFTR channel function in Fischer rat thyroid cells, demonstrating the potential for combination therapeutics to address the defects that cause CF.
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Affiliation(s)
- Stephen Lin
- Zalicus, Inc., Cambridge, Massachusetts, USA
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Sui J, Cotard S, Andersen J, Zhu P, Staunton J, Lee M, Lin S. Optimization of a Yellow fluorescent protein-based iodide influx high-throughput screening assay for cystic fibrosis transmembrane conductance regulator (CFTR) modulators. Assay Drug Dev Technol 2010; 8:656-68. [PMID: 21050066 DOI: 10.1089/adt.2010.0312] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Cystic fibrosis is an inherited, life-threatening disease associated with mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene. The most common mutation, F508del CFTR, is found in 90% of CF patients. The loss of a single amino acid (phenylalanine at position 508) results in malformed CFTR with defective trafficking to the plasma membrane and impaired channel function. A functional assay with cells expressing F508del CFTR has been previously described by others using genetically engineered halide-sensitive yellow fluorescent protein to screen for CFTR modulators. We adapted this yellow fluorescent protein assay to 384-well plate format with a high-throughput screening plate reader, and optimized the assay in terms of data quality, resolution, and throughput, with target-specific protocols. The optimized assay was validated with reference compounds from cystic fibrosis foundation therapeutics. On the basis of the Z-factor range (≥0.5) and the potential productivity, this assay is well suited for high-throughput screening. It was successfully used to screen for active single agent and synergistic combinations of single agent modulators of F508del CFTR from a library collection of current active pharmaceutical ingredients (supported by Cystic Fibrosis Foundation Therapeutics).
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Melani R, Tomati V, Galietta LJV, Zegarra-Moran O. Modulation of cystic fibrosis transmembrane conductance regulator (CFTR) activity and genistein binding by cytosolic pH. J Biol Chem 2010; 285:41591-6. [PMID: 20974851 DOI: 10.1074/jbc.m110.166850] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Potentiators are molecules that increase the activity of the cystic fibrosis transmembrane conductance regulator (CFTR). Some potentiators can also inhibit CFTR at higher concentrations. The activating binding site is thought to be located at the interface of the dimer formed by the two nucleotide-binding domains. We have hypothesized that if binding of potentiators involves titratable residues forming salt bridges, then modifications of cytosolic pH (pH(i)) would alter the binding affinity. Here, we analyzed the effect of pH(i) on CFTR activation and on the binding of genistein, a well known CFTR potentiator. We found that pH(i) does modify CFTR maximum current (I(m)) and half-activation concentration (K(d)): I(m) = 127.7, 185.5, and 231.8 μA/cm(2) and K(d) = 32.7, 56.6 and 71.9 μm at pH 6, 7.35, and 8, respectively. We also found that the genistein apparent dissociation constant for activation (K(a)) increased at alkaline pH(i), near cysteine pK (K(a) = 1.83, 1.81 and 4.99 μm at pH(i) 6, 7.35, and 8, respectively), suggesting the involvement of cysteines in the binding site. Mutations of cysteine residues predicted to be within (Cys-491) or outside (Cys-1344) the potentiator-binding site showed that Cys-491 is responsible for the sensitivity of potentiator binding to alkaline pH(i). Effects of pH(i) on inhibition by high genistein doses were also analyzed. Our results extend previous data about multiple effects of pH(i) on CFTR activity and demonstrate that binding of potentiators involves salt bridge formation with amino acids of nucleotide-binding domain 1.
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Affiliation(s)
- Raffaella Melani
- Laboratorio di Genetica Molecolare, Istituto Giannina Gaslini, 16148 Genoa, Italy
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Pedemonte N, Tomati V, Sondo E, Galietta LJV. Influence of cell background on pharmacological rescue of mutant CFTR. Am J Physiol Cell Physiol 2010; 298:C866-74. [DOI: 10.1152/ajpcell.00404.2009] [Citation(s) in RCA: 104] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Cystic fibrosis (CF) is caused by mutations in the CFTR chloride channel. Deletion of phenylalanine 508 (F508del), the most frequent CF mutation, impairs the maturation and gating of the CFTR protein. Such defects may be corrected in vitro by pharmacological modulators named as correctors and potentiators, respectively. We have evaluated a panel of correctors and potentiators derived from various sources to assess potency, efficacy, and mechanism of action. For this purpose, we have used functional and biochemical assays on two different cell expression systems, Fischer rat thyroid (FRT) and A549 cells. The order of potency and efficacy of potentiators was similar in the two cell types considered, with phenylglycine PG-01 and isoxazole UCCF-152 being the most potent and least potent, respectively. Most potentiators were also effective on two mutations, G551D and G1349D, that cause a purely gating defect. In contrast, corrector effect was strongly affected by cell background, with the extreme case of many compounds working in one cell type only. Our findings are in favor of a direct action of potentiators on CFTR, possibly at a common binding site. In contrast, most correctors seem to work indirectly with various mechanisms of action. Combinations of correctors acting at different levels may lead to additive F508del-CFTR rescue.
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Affiliation(s)
- Nicoletta Pedemonte
- Laboratorio di Genetica Molecolare, Istituto Giannina Gaslini and
- Centro di Biotecnologie Avanzate, Genoa, Italy
| | - Valeria Tomati
- Laboratorio di Genetica Molecolare, Istituto Giannina Gaslini and
| | - Elvira Sondo
- Laboratorio di Genetica Molecolare, Istituto Giannina Gaslini and
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31
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Moran O. Model of the cAMP activation of chloride transport by CFTR channel and the mechanism of potentiators. J Theor Biol 2009; 262:73-9. [PMID: 19766125 DOI: 10.1016/j.jtbi.2009.08.032] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2009] [Revised: 08/12/2009] [Accepted: 08/22/2009] [Indexed: 11/30/2022]
Abstract
Mutations of the cystic fibrosis transmembrane conductance regulator (CFTR) cause cystic fibrosis, a hereditary lethal disease. CFTR is a chloride channel expressed in the apical membrane of epithelia. It is activated by cAMP dependent phosphorylation and gated by the binding of ATP. The impaired chloride transport of some types of cystic fibrosis mutations could be pharmacologically solved by the use of chemical compounds called potentiators. Here it is undertaken the construction of a model of the CFTR activation pathways, and the possible modification produced by a potentiator application. The model yields a novel mechanism for the potentiator action, describing the activatory and inhibitory activities on two different positions in the CFTR activation pathway.
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Moran O, Zegarra-Moran O. On the measurement of the functional properties of the CFTR. J Cyst Fibros 2008; 7:483-94. [PMID: 18818127 DOI: 10.1016/j.jcf.2008.05.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2008] [Revised: 04/01/2008] [Accepted: 05/14/2008] [Indexed: 10/21/2022]
Abstract
A number of methods are currently employed to assess the functional properties of CFTR channels and their response to pharmacological potentiators, correction of the defective CFTR trafficking, and vectorial introduction of new proteins. Here we review the most common methods used to assess CFTR channel function. The suitability of each technique to various experimental conditions is discussed.
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Affiliation(s)
- Oscar Moran
- Istituto di Biofisica, CNR, 16149 Genova, Italy.
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Ferrera L, Pincin C, Moran O. Characterization of a 7,8-benzoflavone double effect on CFTR Cl(-) channel activity. J Membr Biol 2007; 220:1-9. [PMID: 17876495 DOI: 10.1007/s00232-007-9066-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2007] [Accepted: 07/21/2007] [Indexed: 10/22/2022]
Abstract
The human cystic fibrosis transmembrane conductance regulator (CFTR) is a member of the superfamily of adenosine triphosphate (ATP)-binding cassette (ABC) transporter ATPases. This protein forms a Cl(-) channel with a complex regulation; gene mutations cause cystic fibrosis disease. We investigated the interaction between the protein and the flavone UCCF-029 using the patch-clamp technique in the excised inside-out configuration in order to study the molecular mechanism of action for this potentiator on completely phosphorylated channel (25 U/ml protein kinase A) and a relatively low level of ATP (0.3 mM: ). Low concentrations of UCCF-029 (<50 nM: ) increase the open probability (p (o)), favoring the channel transition to an activated state, while high UCCF-029 (>50 nM: ) levels determine inhibition of the CFTR by a reduction of the total open time. Our data suggest that this drug can potentiate CFTR by binding to a specific site on the nucleotide binding domain, promoting dimer formation. The response of CFTR to variable concentrations of ATP is not modified by application of the potentiator UCCF-029 at either low, activatory, concentration or high, inhibitory, levels. Hence, we conclude that the potentiator may not interfere with binding of ATP but probably acts at an independent site in the protein, interacting directly with CFTR to modulate channel activity.
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Affiliation(s)
- Loretta Ferrera
- Istituto di Biofisica, CNR, Via De Marini 6, 16149, Genoa, Italy
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Rubenstein RC. Targeted therapy for cystic fibrosis: cystic fibrosis transmembrane conductance regulator mutation-specific pharmacologic strategies. Mol Diagn Ther 2006; 10:293-301. [PMID: 17022692 DOI: 10.1007/bf03256204] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Cystic fibrosis (CF) results from the absence or dysfunction of a single protein, the CF transmembrane conductance regulator (CFTR). CFTR plays a critical role in the regulation of ion transport in a number of exocrine epithelia. Improvement or restoration of CFTR function, where it is deficient, should improve the CF phenotype. There are >1000 reported disease-causing mutations of the CFTR gene. Recent investigations have afforded a better understanding of the mechanism of dysfunction of many of these mutant CFTRs, and have allowed them to be classified according to their mechanism of dysfunction. These data, as well as an enhanced understanding of the role of CFTR in regulating epithelial ion transport, have led to the development of therapeutic strategies based on pharmacologic enhancement or repair of mutant CFTR dysfunction. The strategy, termed 'protein repair therapy', is aimed at improving the regulation of epithelial ion transport by mutant CFTRs in a mutation-specific fashion. The grouping of CFTR gene mutations, according to mechanism of dysfunction, yields some guidance as to which pharmacologic repair agents may be useful for specific CFTR mutations. Recent data has suggested that combinations of pharmacologic repair agents may be necessary to obtain clinically meaningful CFTR repair. Nevertheless, such strategies to improve mutant CFTR function hold great promise for the development of novel therapies aimed at correcting the underlying pathophysiology of CF.
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Affiliation(s)
- Ronald C Rubenstein
- Division of Pulmonary Medicine and Cystic Fibrosis Center, Children's Hospital of Philadelphia, PA 19104, USA.
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35
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Fang X, Song Y, Hirsch J, Galietta LJV, Pedemonte N, Zemans RL, Dolganov G, Verkman AS, Matthay MA. Contribution of CFTR to apical-basolateral fluid transport in cultured human alveolar epithelial type II cells. Am J Physiol Lung Cell Mol Physiol 2006; 290:L242-9. [PMID: 16143588 DOI: 10.1152/ajplung.00178.2005] [Citation(s) in RCA: 129] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Previous studies in intact lung suggest that CFTR may play a role in cAMP-regulated fluid transport from the distal air spaces of the lung. However, the potential contribution of different epithelial cells (alveolar epithelial type I, type II, or bronchial epithelial cells) to CFTR-regulated fluid transport is unknown. In this study we determined whether the CFTR gene is expressed in human lung alveolar epithelial type II (AT II) cells and whether the CFTR chloride channel contributes to cAMP-regulated fluid transport in cultured human AT II cells. Human AT II cells were isolated and cultured on collagen I-coated Transwell membranes for 120–144 h with an air-liquid interface. The cultured cells retained typical AT II-like features based on morphologic studies. Net basal fluid transport was 0.9 ± 0.1 μl·cm−2·h−1and increased to 1.35 ± 0.11 μl·cm−2·h−1(mean ± SE, n = 18, P < 0.05) by stimulation with cAMP agonists. The CFTR inhibitor, CFTRinh-172, inhibited cAMP stimulated but not basal fluid transport. In short-circuit current ( Isc) studies with an apical-to-basolateral transepithelial Cl−gradient, apical application of CFTRinh-172 reversed the forskolin-induced decrease in Isc. Real time RT-PCR demonstrated CFTR transcript expression in human AT II cells at a level similar to that in airway epithelial cells. We conclude that CFTR is expressed in cultured human AT II cells and may contribute to cAMP-regulated apical-basolateral fluid transport.
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Affiliation(s)
- Xiaohui Fang
- Cardiovascular Research Inst., Department of Medicine/Physiology, Univ. of California, San Francisco, CA 94143-0130, USA.
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Adebamiro A, Cheng Y, Johnson JP, Bridges RJ. Endogenous protease activation of ENaC: effect of serine protease inhibition on ENaC single channel properties. ACTA ACUST UNITED AC 2005; 126:339-52. [PMID: 16186561 PMCID: PMC2266620 DOI: 10.1085/jgp.200509285] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Endogenous serine proteases have been reported to control the reabsorption of Na+ by kidney- and lung-derived epithelial cells via stimulation of electrogenic Na+ transport mediated by the epithelial Na+ channel (ENaC). In this study we investigated the effects of aprotinin on ENaC single channel properties using transepithelial fluctuation analysis in the amphibian kidney epithelium, A6. Aprotinin caused a time- and concentration-dependent inhibition (84 ± 10.5%) in the amiloride-sensitive sodium transport (INa) with a time constant of 18 min and half maximal inhibition constant of 1 μM. Analysis of amiloride analogue blocker–induced fluctuations in INa showed linear rate–concentration plots with identical blocker on and off rates in control and aprotinin-inhibited conditions. Verification of open-block kinetics allowed for the use of a pulse protocol method (Helman, S.I., X. Liu, K. Baldwin, B.L. Blazer-Yost, and W.J. Els. 1998. Am. J. Physiol. 274:C947–C957) to study the same cells under different conditions as well as the reversibility of the aprotinin effect on single channel properties. Aprotinin caused reversible changes in all three single channel properties but only the change in the number of open channels was consistent with the inhibition of INa. A 50% decrease in INa was accompanied by 50% increases in the single channel current and open probability but an 80% decrease in the number of open channels. Washout of aprotinin led to a time-dependent restoration of INa as well as the single channel properties to the control, pre-aprotinin, values. We conclude that protease regulation of INa is mediated by changes in the number of open channels in the apical membrane. The increase in the single channel current caused by protease inhibition can be explained by a hyperpolarization of the apical membrane potential as active Na+ channels are retrieved. The paradoxical increase in channel open probability caused by protease inhibition will require further investigation but does suggest a potential compensatory regulatory mechanism to maintain INa at some minimal threshold value.
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Affiliation(s)
- Adedotun Adebamiro
- Department of Cell Biology and Physiology, University of Pittsburgh, Pittsburgh, PA, USA
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Moran O, Zegarra-Moran O. A quantitative description of the activation and inhibition of CFTR by potentiators: Genistein. FEBS Lett 2005; 579:3979-83. [PMID: 15996659 DOI: 10.1016/j.febslet.2005.06.026] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2005] [Revised: 06/14/2005] [Accepted: 06/15/2005] [Indexed: 11/23/2022]
Abstract
The CFTR, encoded by the gene mutated in cystic fibrosis (CF) patients, is responsible for cAMP dependent chloride transport in epithelia. Substances that activate CFTR have been suggested as possible CF therapy. Most substances investigated so far exert a dual effect on the CFTR: low concentrations stimulate CFTR, whereas higher concentrations inhibit CFTR. Besides, the CFTR phosphorylation level determines the apparent affinity of the drug. We have studied the properties of genistein, the well known CFTR potentiator, by measuring apical membrane current on epithelia formed by cells stably transfected with CFTR and stimulated with different concentrations of CPTcAMP. We propose a quantitative model to describe the activatory and inhibitory effect of genistein, accounting also for the cAMP dependent activation.
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Affiliation(s)
- Oscar Moran
- Instituto di Biofisica, Consiglio Nazionale dela Ricerche, CNR, Via DeMarini, 6, 16149 Genova, Italy.
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Abstract
PURPOSE OF REVIEW Cystic fibrosis results from disruption of the biosynthesis or function of the cystic fibrosis transmembrane conductance regulator. Cystic fibrosis transmembrane conductance regulator plays a critical role in the regulation of epithelial ion transport. Restoration of cystic fibrosis transmembrane conductance regulator function should improve the cystic fibrosis phenotype. RECENT FINDINGS Recent investigations affording a better understanding of the mechanism of dysfunction of mutant cystic fibrosis transmembrane conductance regulators, as well as the roles of cystic fibrosis transmembrane conductance regulator in regulating epithelial ion transport, have led to development of therapeutic strategies based on repair or bypass of mutant cystic fibrosis transmembrane conductance regulator dysfunction. The former strategy, coined 'protein repair therapy,' is aimed at improving or restoring the function of mutant cystic fibrosis transmembrane conductance regulators, whereas the latter approach aims to augment epithelial ion transport to compensate for the absent function mutant cystic fibrosis transmembrane conductance regulator. SUMMARY Strategies to improve mutant cystic fibrosis transmembrane conductance regulator function or to bypass mutant cystic fibrosis transmembrane conductance regulator function hold great promise for development of novel therapies aimed at correcting the underlying pathophysiology of cystic fibrosis.
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Affiliation(s)
- Ronald C Rubenstein
- Department of Pediatrics, University of Pennsylvania School of Medicine, Children's Hospital of Philadelphia, Pennsylvania 19104, USA.
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Amaral MD. Processing of CFTR: traversing the cellular maze--how much CFTR needs to go through to avoid cystic fibrosis? Pediatr Pulmonol 2005; 39:479-91. [PMID: 15765539 DOI: 10.1002/ppul.20168] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Biosynthesis of the cystic fibrosis transmembrane conductance regulator (CFTR), like other proteins aimed at the cell surface, involves transport through a series of membranous compartments, the first of which is the endoplasmic reticulum (ER), where CFTR encounters the appropriate environment for folding, oligomerization, maturation, and export from the ER. After exiting the ER, CFTR has to traffic through complex pathways until it reaches the cell surface. Although not yet fully understood, the fine details of these pathways are starting to emerge, partially through identification of an increasing number of CFTR-interacting proteins (CIPs) and the clarification of their roles in CFTR trafficking and function. These aspects of CFTR biogenesis/degradation and by membrane traffic and CIPs are discussed in this review. Following this description of complex pathways and multiple checkpoints to which CFTR is subjected in the cell, the basic question remains of how much CFTR has to overcome these barriers and be functionally expressed at the plasma membrane to avoid CF. This question is also discussed here.
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Affiliation(s)
- Margarida D Amaral
- Department of Chemistry and Biochemistry, Faculty of Sciences, University of Lisbon, and Centre of Human Genetics, National Institute of Health Dr. Ricardo Jorge, Lisbon, Portugal.
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Szkotak AJ, Murthy M, MacVinish LJ, Duszyk M, Cuthbert AW. 4-Chloro-benzo[F]isoquinoline (CBIQ) activates CFTR chloride channels and KCNN4 potassium channels in Calu-3 human airway epithelial cells. Br J Pharmacol 2004; 142:531-42. [PMID: 15148241 PMCID: PMC1574981 DOI: 10.1038/sj.bjp.0705846] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
1 Calu-3 cells have been used to investigate the actions of 4-chloro-benzo[F]isoquinoline (CBIQ) on short-circuit current (SCC) in monolayers, whole-cell recording from single cells and by patch clamping. 2 CBIQ caused a sustained, reversible and repeatable increase in SCC in Calu-3 monolayers with an EC50 of 4.0 microm. Simultaneous measurements of SCC and isotopic fluxes of 36Cl- showed that CBIQ caused electrogenic chloride secretion. 3 Apical membrane permeabilisation to allow recording of basolateral membrane conductance in the presence of a K+ gradient suggested that CBIQ activated the intermediate-conductance calcium-sensitive K(+)-channel (KCNN4). Permeabilisation of the basolateral membranes of epithelial monolayers in the presence of a Cl- gradient suggested that CBIQ activated the Cl(-)-channel CFTR in the apical membrane. 4 Whole-cell recording in the absence of ATP/GTP of Calu-3 cells showed that CBIQ generated an inwardly rectifying current sensitive to clotrimazole. In the presence of the nucleotides, a more complex I/V relation was found that was partially sensitive to glibenclamide. The data are consistent with the presence of both KCNN4 and CFTR in Calu-3. 5 Isolated inside-out patches from Calu-3 cells revealed clotrimazole-sensitive channels with a conductance of 12 pS at positive potentials after activation with CBIQ and demonstrating inwardly rectifying properties, consistent with the known properties of KCNN4. Cell-attached patches showed single channel events with a conductance of 7 pS and a linear I/V relation that were further activated by CBIQ by an increase in open state probability, consistent with known properties of CFTR. It is concluded that CBIQ activates CFTR and KCNN4 ion channels in Calu-3 cells.
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Affiliation(s)
- A J Szkotak
- Department of Physiology, University of Alberta, Edmonton, Alberta, Canada
| | - M Murthy
- Department of Medicine, University of Cambridge, Addenbrooke's Hospital (Level5, Box 157), Hills Road, Cambridge
| | - L J MacVinish
- Department of Medicine, University of Cambridge, Addenbrooke's Hospital (Level5, Box 157), Hills Road, Cambridge
| | - M Duszyk
- Department of Physiology, University of Alberta, Edmonton, Alberta, Canada
| | - A W Cuthbert
- Department of Medicine, University of Cambridge, Addenbrooke's Hospital (Level5, Box 157), Hills Road, Cambridge
- Author for correspondence:
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Cuthbert AW, MacVinish LJ. Mechanisms of anion secretion in Calu-3 human airway epithelial cells by 7,8-benzoquinoline. Br J Pharmacol 2003; 140:81-90. [PMID: 12967937 PMCID: PMC1574001 DOI: 10.1038/sj.bjp.0705403] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
(1) Cultured epithelial monolayers of Calu-3 human airway cells were used to measure anion secretion in response to a number of phenanthrolines and benzoquinolines, using short-circuit current measurements. Calu-3 cells are derived from serous cells of submucosal glands of the airways and are a target for conditions in which muco-ciliary clearance is compromised. (2) Compounds studied were 5,6-benzoquinoline, 5-chloro-1,10-phenanthroline, 7,8-benzoquinoline, 5-nitro-1,10-phenanthroline, benzo[c]cinnoline and 1,10-phenanthroline, which gave EC50 values of 34, 48, 123, 235, 192 and 217 microm, respectively. Of these, 7,8-benzoquinoline was chosen for further detailed study. Concentration-response relationships for all the compounds had Hill slopes greater than 1. (3) Permeabilisation of the apical surface of epithelia with nystatin in the presence of an apical to basolateral potassium ion gradient reduced the EC50 for 7,8-benzoquinoline to 31 microm and altered the Hill slope to close to 1. (4) Using apically permeabilised epithelia it was shown that 7,8-benzoquinoline activates an intermediate-conductance calcium-sensitive potassium channel (KCNN4) and a cAMP-sensitive potassium channel (KCNQ1/KCNE3) in the basolateral epithelial membranes. (5) 7,8-Benzoquinoline was shown to increase chloride conductance of apical epithelial membranes, presumed to be by activation of the cystic fibrosis transmembrane conductance regulator. (6) 7,8-Benzoquinoline had a minor effect on cAMP accumulation in Calu-3 cells, probably by inhibition of phosphodiesterase, which may contribute to its effect on CFTR- and cAMP-sensitive potassium channels. (7) The usefulness of these novel actions in promoting secretion in airway submucosal glands is discussed.
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Affiliation(s)
- A W Cuthbert
- Department of Medicine, University of Cambridge, Addenbrooke's Hospital (Level 5, Box 157), Hills Road, Cambridge CB2 2QQ.
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Cuthbert AW, Supuran CT, MacVinish LJ. Bicarbonate-dependent chloride secretion in Calu-3 epithelia in response to 7,8-benzoquinoline. J Physiol 2003; 551:79-92. [PMID: 12872009 PMCID: PMC2343133 DOI: 10.1113/jphysiol.2003.046482] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Stimulation of Calu-3 epithelia with 7,8-benzoquinoline, under short circuit current conditions, produced a current increase that was completely accounted for by the net flux of chloride, measured simultaneously with 36Cl-. Nevertheless the current stimulated by 7,8-benzoquinoline was sensitive to acetazolamide, which caused up to 50 % inhibition of the stimulated current, the remainder being sensitive to the Na+-K+-2Cl- cotransport inhibitor bumetanide. The effects of acetazolamide could be mimicked by either amiloride or by the di-sodium salt of 4,4'-dinitrostilbene-2,2'-disulphonic acid (DNDS) added to the basolateral side of the epithelium, but their actions were not additive. Amiloride was needed in sufficient concentration to inhibit the sodium-proton exchanger NHE1. DNDS blocks both the chloride-bicarbonate exchanger AE2 and the sodium-bicarbonate transporter NBC1. However, since 7,8-benzoquinoline activates basolateral K+ channels, causing hyperpolarisation, it is unlikely NBC1 is active after addition of 7,8-benzoquinoline. The effect of DNDS is, therefore, mainly on AE2. It is concluded that chloride enters the basolateral aspect of the cells using the Na+-K+-2Cl- cotransporter and a parallel arrangement of NHE1 with AE2, these latter two being sensitive to acetazolamide because of their association with the cytoplasmic form of carbonic anhydrase CAII. The effects of acetazolamide could be mimicked by removal of HCO3-/CO2 from the bathing medium, and furthermore showed that the NHE1-AE2 mechanism is particularly important when the transport rate is high. Thus part of the current stimulated by 7,8-benzoquinoline and inhibited by acetazolamide or HCO3-/CO2 removal can be said to represent bicarbonate-dependent chloride secretion.
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Affiliation(s)
- A W Cuthbert
- Department of Medicine, University of Cambridge, Addenbrooke's Hospital, Level 5 Box 157, Hills Road, Cambridge CB2 2QQ, UK.
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