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Zajac M, Dreano E, Edwards A, Planelles G, Sermet-Gaudelus I. Airway Surface Liquid pH Regulation in Airway Epithelium Current Understandings and Gaps in Knowledge. Int J Mol Sci 2021; 22:3384. [PMID: 33806154 PMCID: PMC8037888 DOI: 10.3390/ijms22073384] [Citation(s) in RCA: 45] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Revised: 03/08/2021] [Accepted: 03/08/2021] [Indexed: 12/22/2022] Open
Abstract
Knowledge on the mechanisms of acid and base secretion in airways has progressed recently. The aim of this review is to summarize the known mechanisms of airway surface liquid (ASL) pH regulation and their implication in lung diseases. Normal ASL is slightly acidic relative to the interstitium, and defects in ASL pH regulation are associated with various respiratory diseases, such as cystic fibrosis. Basolateral bicarbonate (HCO3-) entry occurs via the electrogenic, coupled transport of sodium (Na+) and HCO3-, and, together with carbonic anhydrase enzymatic activity, provides HCO3- for apical secretion. The latter mainly involves CFTR, the apical chloride/bicarbonate exchanger pendrin and paracellular transport. Proton (H+) secretion into ASL is crucial to maintain its relative acidity compared to the blood. This is enabled by H+ apical secretion, mainly involving H+/K+ ATPase and vacuolar H+-ATPase that carry H+ against the electrochemical potential gradient. Paracellular HCO3- transport, the direction of which depends on the ASL pH value, acts as an ASL protective buffering mechanism. How the transepithelial transport of H+ and HCO3- is coordinated to tightly regulate ASL pH remains poorly understood, and should be the focus of new studies.
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Affiliation(s)
- Miroslaw Zajac
- Department of Physics and Biophysics, Institute of Biology, Warsaw University of Life Sciences, 02-776 Warsaw, Poland;
| | - Elise Dreano
- Institut Necker Enfants Malades, INSERM U1151, 75015 Paris, France;
- Centre de Recherche des Cordeliers, Sorbonne Université, INSERM, Université de Paris, 75006 Paris, France;
| | - Aurelie Edwards
- Department of Biomedical Engineering, Boston University, Boston, MA 02215, USA;
| | - Gabrielle Planelles
- Centre de Recherche des Cordeliers, Sorbonne Université, INSERM, Université de Paris, 75006 Paris, France;
- Laboratoire de Physiologie rénale et Tubulopathies, CNRS ERL 8228, 75006 Paris, France
| | - Isabelle Sermet-Gaudelus
- Institut Necker Enfants Malades, INSERM U1151, 75015 Paris, France;
- Centre de Recherche des Cordeliers, Sorbonne Université, INSERM, Université de Paris, 75006 Paris, France;
- Centre de Référence Maladies Rares, Mucoviscidose et Maladies de CFTR, Hôpital Necker Enfants Malades, 75015 Paris, France
- Clinical Trial Network, European Cystic Fibrosis Society, BT2 Belfast, Ireland
- European Respiratory Network Lung, 75006 Paris, France
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Trampert DC, van de Graaf SFJ, Jongejan A, Oude Elferink RPJ, Beuers U. Hepatobiliary acid-base homeostasis: Insights from analogous secretory epithelia. J Hepatol 2021; 74:428-441. [PMID: 33342564 DOI: 10.1016/j.jhep.2020.10.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Revised: 10/03/2020] [Accepted: 10/19/2020] [Indexed: 12/14/2022]
Abstract
Many epithelia secrete bicarbonate-rich fluid to generate flow, alter viscosity, control pH and potentially protect luminal and intracellular structures from chemical stress. Bicarbonate is a key component of human bile and impaired biliary bicarbonate secretion is associated with liver damage. Major efforts have been undertaken to gain insight into acid-base homeostasis in cholangiocytes and more can be learned from analogous secretory epithelia. Extrahepatic examples include salivary and pancreatic duct cells, duodenocytes, airway and renal epithelial cells. The cellular machinery involved in acid-base homeostasis includes carbonic anhydrase enzymes, transporters of the solute carrier family, and intra- and extracellular pH sensors. This pH-regulatory system is orchestrated by protein-protein interactions, the establishment of an electrochemical gradient across the plasma membrane and bicarbonate sensing of the intra- and extracellular compartment. In this review, we discuss conserved principles identified in analogous secretory epithelia in the light of current knowledge on cholangiocyte physiology. We present a framework for cholangiocellular acid-base homeostasis supported by expression analysis of publicly available single-cell RNA sequencing datasets from human cholangiocytes, which provide insights into the molecular basis of pH homeostasis and dysregulation in the biliary system.
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Affiliation(s)
- David C Trampert
- Amsterdam UMC, University of Amsterdam, Department of Gastroenterology and Hepatology, Tytgat Institute for Liver and Intestinal Research, Amsterdam Gastroenterology Endocrinology Metabolism (AGEM), Meibergdreef 9, Amsterdam, the Netherlands
| | - Stan F J van de Graaf
- Amsterdam UMC, University of Amsterdam, Department of Gastroenterology and Hepatology, Tytgat Institute for Liver and Intestinal Research, Amsterdam Gastroenterology Endocrinology Metabolism (AGEM), Meibergdreef 9, Amsterdam, the Netherlands
| | - Aldo Jongejan
- Amsterdam UMC, University of Amsterdam, Department of Clinical Epidemiology, Biostatistics and Bioinformatics, Meibergdreef 9, Amsterdam, the Netherlands
| | - Ronald P J Oude Elferink
- Amsterdam UMC, University of Amsterdam, Department of Gastroenterology and Hepatology, Tytgat Institute for Liver and Intestinal Research, Amsterdam Gastroenterology Endocrinology Metabolism (AGEM), Meibergdreef 9, Amsterdam, the Netherlands
| | - Ulrich Beuers
- Amsterdam UMC, University of Amsterdam, Department of Gastroenterology and Hepatology, Tytgat Institute for Liver and Intestinal Research, Amsterdam Gastroenterology Endocrinology Metabolism (AGEM), Meibergdreef 9, Amsterdam, the Netherlands.
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Brinkmann F, Hanusch B, Ballmann M, Mayorandan S, Bollenbach A, Chobanyan-Jürgens K, Jansen K, Schmidt-Choudhury A, Derichs N, Tsikas D, Lücke T. Activated L-Arginine/Nitric Oxide Pathway in Pediatric Cystic Fibrosis and Its Association with Pancreatic Insufficiency, Liver Involvement and Nourishment: An Overview and New Results. J Clin Med 2020; 9:jcm9062012. [PMID: 32604946 PMCID: PMC7356307 DOI: 10.3390/jcm9062012] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Revised: 06/15/2020] [Accepted: 06/23/2020] [Indexed: 02/07/2023] Open
Abstract
Cystic fibrosis (CF; OMIM 219700) is a rare genetic disorder caused by a chloride channel defect, resulting in lung disease, pancreas insufficiency and liver impairment. Altered L-arginine (Arg)/nitric oxide (NO) metabolism has been observed in CF patients’ lungs and in connection with malnutrition. The aim of the present study was to investigate markers of the Arg/NO pathway in the plasma and urine of CF patients and to identify possible risk factors, especially associated with malnutrition. We measured the major NO metabolites nitrite and nitrate, Arg, a semi-essential amino acid and NO precursor, the NO synthesis inhibitor asymmetric dimethylarginine (ADMA) and its major urinary metabolite dimethylamine (DMA) in plasma and urine samples of 70 pediatric CF patients and 78 age-matched healthy controls. Biomarkers were determined by gas chromatography–mass spectrometry and high-performance liquid chromatography. We observed higher plasma Arg (90.3 vs. 75.6 µM, p < 0.0001), ADMA (0.62 vs. 0.57 µM, p = 0.03), Arg/ADMA ratio (148 vs. 135, p = 0.01), nitrite (2.07 vs. 1.95 µM, p = 0.03) and nitrate (43.3 vs. 33.1 µM, p < 0.001) concentrations, as well as higher urinary DMA (57.9 vs. 40.7 µM/mM creatinine, p < 0.001) and nitrate (159 vs. 115 µM/mM creatinine, p = 0.001) excretion rates in the CF patients compared to healthy controls. CF patients with pancreatic sufficiency showed plasma concentrations of the biomarkers comparable to those of healthy controls. Malnourished CF patients had lower Arg/ADMA ratios (p = 0.02), indicating a higher NO synthesis capacity in sufficiently nourished CF patients. We conclude that NO production, protein-arginine dimethylation, and ADMA metabolism is increased in pediatric CF patients. Pancreas and liver function influence Arg/NO metabolism. Good nutritional status is associated with higher NO synthesis capacity and lower protein-arginine dimethylation.
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Affiliation(s)
- Folke Brinkmann
- University Children’s Hospital, Ruhr University, 44791 Bochum, Germany; (F.B.); (M.B.); (K.J.); (A.S.-C.); (T.L.)
| | - Beatrice Hanusch
- University Children’s Hospital, Ruhr University, 44791 Bochum, Germany; (F.B.); (M.B.); (K.J.); (A.S.-C.); (T.L.)
- Correspondence: ; Tel.: +49-234-5092615
| | - Manfred Ballmann
- University Children’s Hospital, Ruhr University, 44791 Bochum, Germany; (F.B.); (M.B.); (K.J.); (A.S.-C.); (T.L.)
- Paediatric Clinic, University Medicine Rostock, 18057 Rostock, Germany
| | - Sebene Mayorandan
- Department of Paediatrics, Hannover Medical School, 30623 Hannover, Germany; (S.M.); (K.C.-J.); (N.D.)
- Department of Paediatrics, University Clinic Münster, 48149 Münster, Germany
| | - Alexander Bollenbach
- Institute of Toxicology, Core Unit Proteomics, Hannover Medical School, 30623 Hannover, Germany; (A.B.); (D.T.)
| | - Kristine Chobanyan-Jürgens
- Department of Paediatrics, Hannover Medical School, 30623 Hannover, Germany; (S.M.); (K.C.-J.); (N.D.)
- Department of Clinical Pharmacology and Pharmacoepidemiology, Heidelberg University Hospital, 69120 Heidelberg, Germany
- Department of General Pediatrics, Neuropediatrics, Metabolism, Gastroenterology, Nephrology, Center for Pediatric and Adolescent Medicine, University Hospital Heidelberg, 69120 Heidelberg, Germany
- Pediatric Clinical-Pharmacological Trial Center (paedKliPS), Center for Pediatric and Adolescent Medicine, University Hospital Heidelberg, 69120 Heidelberg, Germany
| | - Kathrin Jansen
- University Children’s Hospital, Ruhr University, 44791 Bochum, Germany; (F.B.); (M.B.); (K.J.); (A.S.-C.); (T.L.)
| | - Anjona Schmidt-Choudhury
- University Children’s Hospital, Ruhr University, 44791 Bochum, Germany; (F.B.); (M.B.); (K.J.); (A.S.-C.); (T.L.)
| | - Nico Derichs
- Department of Paediatrics, Hannover Medical School, 30623 Hannover, Germany; (S.M.); (K.C.-J.); (N.D.)
- KinderPneumologieDerichs, Pediatric Pneumology and Allergology, CFTR & Pulmonary Research Center, 30173 Hannover, Germany
| | - Dimitrios Tsikas
- Institute of Toxicology, Core Unit Proteomics, Hannover Medical School, 30623 Hannover, Germany; (A.B.); (D.T.)
| | - Thomas Lücke
- University Children’s Hospital, Ruhr University, 44791 Bochum, Germany; (F.B.); (M.B.); (K.J.); (A.S.-C.); (T.L.)
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Steiger AK, Zhao Y, Pluth MD. Emerging Roles of Carbonyl Sulfide in Chemical Biology: Sulfide Transporter or Gasotransmitter? Antioxid Redox Signal 2018; 28:1516-1532. [PMID: 28443679 PMCID: PMC5930797 DOI: 10.1089/ars.2017.7119] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Accepted: 04/16/2017] [Indexed: 12/19/2022]
Abstract
SIGNIFICANCE Carbonyl sulfide (COS) is the most prevalent sulfur-containing gas in the Earth's atmosphere, and it plays important roles in the global sulfur cycle. COS has been implicated in origin of life peptide ligation, is the primary energy source for certain bacteria, and has been detected in mammalian systems. Despite this long and intertwined history with terrestrial biology, limited attention has focused on potential roles of COS as a biological mediator. Recent Advances: Although bacterial COS production is well documented, definitive sources of mammalian COS production have not been confirmed. Enzymatic COS consumption in mammals, however, is well documented and occurs primarily by carbonic anhydrase (CA)-mediated conversion to hydrogen sulfide (H2S). COS has been detected in ex vivo mammalian tissue culture, as well as in exhaled breath as a potential biomarker for different disease pathologies, including cystic fibrosis and organ rejection. Recently, chemical tools for COS delivery have emerged and are poised to advance future investigations into the role of COS in different biological contexts. CRITICAL ISSUES Possible roles of COS as an important biomolecule, gasotransmitter, or sulfide transport intermediate remain to be determined. Key advances in both biological and chemical tools for COS research are needed to further investigate these questions. FUTURE DIRECTIONS Further evaluation of the biological roles of COS and disentangling the chemical biology of COS from that of H2S are needed to further elucidate these interactions. Chemical tools for COS delivery and modulation may provide a first avenue of investigative tools to answer many of these questions. Antioxid. Redox Signal. 28, 1516-1532.
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Affiliation(s)
- Andrea K Steiger
- Department of Chemistry and Biochemistry, Institute of Molecular Biology, Materials Science Institute, University of Oregon , Eugene, Oregon
| | - Yu Zhao
- Department of Chemistry and Biochemistry, Institute of Molecular Biology, Materials Science Institute, University of Oregon , Eugene, Oregon
| | - Michael D Pluth
- Department of Chemistry and Biochemistry, Institute of Molecular Biology, Materials Science Institute, University of Oregon , Eugene, Oregon
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Yin J, Tse CM, Avula LR, Singh V, Foulke-Abel J, de Jonge HR, Donowitz M. Molecular Basis and Differentiation-Associated Alterations of Anion Secretion in Human Duodenal Enteroid Monolayers. Cell Mol Gastroenterol Hepatol 2018; 5:591-609. [PMID: 29930980 PMCID: PMC6009799 DOI: 10.1016/j.jcmgh.2018.02.002] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Accepted: 02/05/2018] [Indexed: 12/12/2022]
Abstract
BACKGROUND & AIMS Human enteroids present a novel tool to study human intestinal ion transport physiology and pathophysiology. The present study describes the contributions of Cl- and HCO3- secretion to total cyclic adenosine monophosphate (cAMP)-stimulated electrogenic anion secretion in human duodenal enteroid monolayers and the relevant changes after differentiation. METHODS Human duodenal enteroids derived from 4 donors were grown as monolayers and differentiated by a protocol that includes the removal of Wnt3A, R-spondin1, and SB202190 for 5 days. The messenger RNA level and protein expression of selected ion transporters and carbonic anhydrase isoforms were determined by quantitative real-time polymerase chain reaction and immunoblotting, respectively. Undifferentiated and differentiated enteroid monolayers were mounted in the Ussing chamber/voltage-current clamp apparatus, using solutions that contained as well as lacked Cl- and HCO3-/CO2, to determine the magnitude of forskolin-induced short-circuit current change and its sensitivity to specific inhibitors that target selected ion transporters and carbonic anhydrase(s). RESULTS Differentiation resulted in a significant reduction in the messenger RNA level and protein expression of cystic fibrosis transmembrane conductance regulator, (CFTR) Na+/K+/2Cl- co-transporter 1 (NKCC1), and potassium channel, voltage gated, subfamily E, regulatory subunit 3 (KCNE3); and, conversely, increase of down-regulated-in-adenoma (DRA), electrogenic Na+/HCO3- co-transporter 1 (NBCe1), carbonic anhydrase 2 (CA2), and carbonic anhydrase 4 (CA4). Both undifferentiated and differentiated enteroids showed active cAMP-stimulated anion secretion that included both Cl- and HCO3- secretion as the magnitude of total active anion secretion was reduced after the removal of extracellular Cl- or HCO3-/CO2. The magnitude of total anion secretion in differentiated enteroids was approximately 33% of that in undifferentiated enteroids, primarily owing to the reduction in Cl- secretion with no significant change in HCO3- secretion. Anion secretion was consistently lower but detectable in differentiated enteroids compared with undifferentiated enteroids in the absence of extracellular Cl- or HCO3-/CO2. Inhibiting CFTR, NKCC1, carbonic anhydrase(s), cAMP-activated K+ channel(s), and Na+/K+-adenosine triphosphatase reduced cAMP-stimulated anion secretion in both undifferentiated and differentiated enteroids. CONCLUSIONS Human enteroids recapitulate anion secretion physiology of small intestinal epithelium. Enteroid differentiation is associated with significant alterations in the expression of several ion transporters and carbonic anhydrase isoforms, leading to a reduced but preserved anion secretory phenotype owing to markedly reduced Cl- secretion but no significant change in HCO3- secretion.
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Key Words
- AE2, anion exchanger 2
- Bicarbonate Secretion
- CA, carbonic anhydrase
- CFTR, cystic fibrosis transmembrane conductance regulator
- Chloride Secretion
- DRA
- DRA, down-regulated-in-adenoma
- Ion Transport
- Isc, short-circuit current
- KRB, Krebs–Ringer bicarbonate
- NBC, Na+/HCO3- co-transporter
- NBCe1, electrogenic Na+/HCO3- co-transporter 1
- NHE, Na+/H+ exchanger
- NKCC1, Na+/K+/2Cl- co-transporter 1
- SDS, sodium dodecyl sulfate
- SITS, 4-Acetamido-4′-isothiocyanato-2,2′-stilbenedisulfonic acid disodium salt hydrate
- TER, transepithelial electrical resistance
- cAMP, cyclic adenosine monophosphate
- mRNA, messenger ribonucleic acid
- qRT-PCR, quantitative real-time polymerase chain reaction
- ΔIsc, change in short-circuit current
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Affiliation(s)
- Jianyi Yin
- Department of Medicine, Division of Gastroenterology and Hepatology, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Chung-Ming Tse
- Department of Medicine, Division of Gastroenterology and Hepatology, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Leela Rani Avula
- Department of Medicine, Division of Gastroenterology and Hepatology, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Varsha Singh
- Department of Medicine, Division of Gastroenterology and Hepatology, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Jennifer Foulke-Abel
- Department of Medicine, Division of Gastroenterology and Hepatology, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Hugo R. de Jonge
- Department of Gastroenterology and Hepatology, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Mark Donowitz
- Department of Medicine, Division of Gastroenterology and Hepatology, Johns Hopkins University School of Medicine, Baltimore, Maryland,Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, Maryland,Correspondence Address correspondence to: Mark Donowitz, MD, Johns Hopkins University School of Medicine, 720 Rutland Avenue, 925 Ross Research Building, Baltimore, Maryland 21205. fax: (410) 955-9677.
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Abstract
The human exocrine pancreas consists of 2 main cell types: acinar and ductal cells. These exocrine cells interact closely to contribute to the secretion of pancreatic juice. The most important ion in terms of the pancreatic ductal secretion is HCO3. In fact, duct cells produce an alkaline fluid that may contain up to 140 mM NaHCO3, which is essential for normal digestion. This article provides an overview of the basics of pancreatic ductal physiology and pathophysiology. In the first part of the article, we discuss the ductal electrolyte and fluid transporters and their regulation. The central role of cystic fibrosis transmembrane conductance regulator (CFTR) is highlighted, which is much more than just a Cl channel. We also review the role of pancreatic ducts in severe debilitating diseases such as cystic fibrosis (caused by various genetic defects of cftr), pancreatitis, and diabetes mellitus. Stimulation of ductal secretion in cystic fibrosis and pancreatitis may have beneficial effects in their treatment.
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Lee MG, Ohana E, Park HW, Yang D, Muallem S. Molecular mechanism of pancreatic and salivary gland fluid and HCO3 secretion. Physiol Rev 2012; 92:39-74. [PMID: 22298651 DOI: 10.1152/physrev.00011.2011] [Citation(s) in RCA: 273] [Impact Index Per Article: 22.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Fluid and HCO(3)(-) secretion is a vital function of all epithelia and is required for the survival of the tissue. Aberrant fluid and HCO(3)(-) secretion is associated with many epithelial diseases, such as cystic fibrosis, pancreatitis, Sjögren's syndrome, and other epithelial inflammatory and autoimmune diseases. Significant progress has been made over the last 20 years in our understanding of epithelial fluid and HCO(3)(-) secretion, in particular by secretory glands. Fluid and HCO(3)(-) secretion by secretory glands is a two-step process. Acinar cells secrete isotonic fluid in which the major salt is NaCl. Subsequently, the duct modifies the volume and electrolyte composition of the fluid to absorb the Cl(-) and secrete HCO(3)(-). The relative volume secreted by acinar and duct cells and modification of electrolyte composition of the secreted fluids varies among secretory glands to meet their physiological functions. In the pancreas, acinar cells secrete a small amount of NaCl-rich fluid, while the duct absorbs the Cl(-) and secretes HCO(3)(-) and the bulk of the fluid in the pancreatic juice. Fluid secretion appears to be driven by active HCO(3)(-) secretion. In the salivary glands, acinar cells secrete the bulk of the fluid in the saliva that is driven by active Cl(-) secretion and contains high concentrations of Na(+) and Cl(-). The salivary glands duct absorbs both the Na(+) and Cl(-) and secretes K(+) and HCO(3)(-). In this review, we focus on the molecular mechanism of fluid and HCO(3)(-) secretion by the pancreas and salivary glands, to highlight the similarities of the fundamental mechanisms of acinar and duct cell functions, and to point out the differences to meet gland-specific secretions.
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Affiliation(s)
- Min Goo Lee
- Department of Pharmacology, Yonsei University College of Medicine, Seoul, Korea
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Fanjul M, Alvarez L, Hollande E. Expression and subcellular localization of a 35-kDa carbonic anhydrase IV in a human pancreatic ductal cell line (Capan-1). J Histochem Cytochem 2007; 55:783-94. [PMID: 17409381 DOI: 10.1369/jhc.6a7112.2007] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The high intraluminal concentrations of HCO(3)(-) in the human pancreatic ducts have suggested the existence of a membrane protein supplying the Cl(-)/HCO(3)(-) exchanger. Membrane-bound carbonic anhydrase IV (CA IV) is one of the potential candidates for this protein. The difficulties in isolating human pancreatic ducts have led the authors to study the molecular mechanisms of HCO(3)(-) secretion in cancerous cell lines. In this work, we have characterized the CA IV expressed in Capan-1 cells. A 35-kDa CA IV was detected in cell homogenates and purified plasma membranes. Treatment of purified plasma membranes with phosphatidylinositol-phospholipase-C indicated that this CA IV was not anchored by a glycosylphosphatidylinositol (GPI). In contrast, its detection on purified plasma membranes by an antibody specifically directed against the carboxyl terminus of human immature GPI-anchored CA IV indicated that it was anchored by a C-terminal hydrophobic segment. Immunoelectron microscopy and double-labeling immunofluorescence revealed that this CA IV was present on apical plasma membranes, and in the rough endoplasmic reticulum, the endoplasmic reticulum-Golgi intermediate compartment, the Golgi complex, and secretory granules, suggesting its transport via the classical biosynthesis/secretory pathway. The expression in Capan-1 cells of a 35-kDa CA IV anchored in the apical plasma membrane through a hydrophobic segment, as is the case in the healthy human pancreas, should make the study of its role in pancreatic HCO(3)(-) secretion easier.
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Affiliation(s)
- Marjorie Fanjul
- INSERM U.858/12MR, Equipe 16, CHU Rangueil, Toulouse, France
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Li L, Falany CN. Elevated hepatic SULT1E1 activity in mouse models of cystic fibrosis alters the regulation of estrogen responsive proteins. J Cyst Fibros 2006; 6:23-30. [PMID: 16798114 DOI: 10.1016/j.jcf.2006.05.001] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2006] [Revised: 04/27/2006] [Accepted: 05/02/2006] [Indexed: 12/01/2022]
Abstract
BACKGROUND Previous studies with cystic fibrosis transmembrane conductance regulator (CFTR) DeltaF508 mice indicate that estrogen levels may play a role in the occurrence or severity of CF-associated liver disease. However, the underlying mechanisms of liver disease in CF are poorly understood. METHODS The levels of SULT1E1 (estrogen sulfotransferase) were measured in livers of control and CFTR-knockout (KO) mice. The impact of increased SULT1E1 activity on hepatic protein expression was assessed by immunoblot and MALDI mass spectrometric analysis. RESULTS SULT1E1 expression was significantly elevated in livers of several CFTR-KO mice. SULT1E1 and CFTR were specifically detected in hepatocytes and cholangiocytes, respectively. Elevated SULT1E1 activity may result in lower levels of free beta-estradiol thereby altering estrogen-responsive hepatic protein expression. Estrogen receptors (ER)-alpha and beta were differentially regulated in CFTR-KO and CFTR-DeltaF508 mice. ERalpha expression was reduced in mice with high SULT1E1 activity. Glutathione S-transferase-P1 and carbonic anhydrase III were significantly decreased in CFTR (-/-) mice with high SULT1E1 activity. Furthermore, cytochrome P450 2B9, also estrogen regulated, was significantly induced in the livers of CFTR (-/-) mice with high SULT1E1 activity. CONCLUSIONS Elevated SULT1E1 levels and associated alterations in estrogen-regulated hepatic protein expression may play an important role in CF liver disease.
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Affiliation(s)
- Li Li
- Department of Pharmacology and Toxicology, 1670 University Blvd., Volker Hall G133M, University of Alabama at Birmingham, Birmingham, AL 35294, USA
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Rakonczay Z, Fearn A, Hegyi P, Boros I, Gray MA, Argent BE. Characterization of H + and HCO 3- transporters in CFPAC-1 human pancreatic duct cells. World J Gastroenterol 2006; 12:885-95. [PMID: 16521216 PMCID: PMC4066153 DOI: 10.3748/wjg.v12.i6.885] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
AIM: To characterize H+ and HCO3- transporters in polarized CFPAC-1 human pancreatic duct cells, which were derived from a cystic fibrosis patient with the ΔF508 CFTR mutation.
METHODS: CFPAC-1 cells were seeded at high density onto permeable supports and grown to confluence. The cells were loaded with the pH-sensitive fluorescent dye BCECF, and mounted into a perfusion chamber, which allowed the simultaneous perfusion of the basolateral and apical membranes. Transmembrane base flux was calculated from the changes in intracellular pH and the buffering capacity of the cells.
RESULTS: Our results showed differential permeability to HCO3-/CO2 at the apical and basolateral membranes of CFPAC-1 cells. Na+/HCO3- co-transporters (NBCs) and Cl-/HCO3- exchangers (AEs) were present on the basolateral membrane, and Na+/H+ exchangers (NHEs) on both the apical and basolateral membranes of the cells. Basolateral HCO3- uptake was sensitive to variations of extracellular K+ concentration, the membrane permeable carbonic anhydrase (CA) inhibitors acetazolamide (100 µmol/L) and ethoxyzolamide (100 µmol/L), and was partially inhibited by H2-DIDS (600 µmol/L). The membrane-impermeable CA inhibitor 1-N-(4-sulfamoylphenylethyl)-2,4,6-trimethylpyridine perchlorate did not have any effect on HCO3- uptake. The basolateral AE had a much higher activity than that in the apical membrane, whereas there was no such difference with the NHE under resting conditions. Also, 10 µmol/L forskolin did not significantly influence Cl-/HCO3- exchange on the apical and basolateral membranes. The administration of 250 µmol/L H2-DIDS significantly inhibited the basolateral AE. Amiloride (300 µmol/L) completely inhibited NHEs on both membranes of the cells. RT-PCR revealed the expression of pNBC1, AE2, and NHE1 mRNA.
CONCLUSION: These data suggest that apart from the lack of CFTR and apical Cl-/HCO3- exchanger activity, CFPAC-1 cells express similar H+ and HCO3- transporters to those observed in native animal tissue.
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Affiliation(s)
- Zoltan Rakonczay
- Institute for Cell and Molecular Biosciences, University of Newcastle upon Tyne, Medical School, Framlington Place, Newcastle upon Tyne NE2 4HH, United Kingdom
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Kamboures MA, Blake DR, Cooper DM, Newcomb RL, Barker M, Larson JK, Meinardi S, Nussbaum E, Rowland FS. Breath sulfides and pulmonary function in cystic fibrosis. Proc Natl Acad Sci U S A 2005; 102:15762-7. [PMID: 16247007 PMCID: PMC1276081 DOI: 10.1073/pnas.0507263102] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
We have determined the concentrations of carbonyl sulfide (OCS), dimethylsulfide, and carbon disulfide (CS(2)) in the breath of a group of cystic fibrosis (CF) patients and one of healthy controls. At the detection sensitivity in these experiments, room air always contained measurable quantities of these three gases. For each subject the inhaled room concentrations were subtracted from the time-coincident concentrations in exhaled breath air. The most significant differences between the CF and control cohorts in these breath-minus-room values were found for OCS. The control group demonstrated a net uptake of 250 +/- 20 parts-per-trillion-by-volume (pptv), whereas the CF cohort had a net uptake of 110 +/- 60 pptv (P = 0.00003). Three CF patients exhaled more OCS than they inhaled from the room. The OCS concentrations in the CF cohort were strongly correlated with pulmonary function. The dimethylsulfide concentrations in breath were greatly enhanced over ambient, but no significant difference was observed between the CF and healthy control groups. The net (breath minus room) CS(2) concentrations for individuals ranged between +180 and -100 pptv. They were slightly greater in the CF cohort (+26 +/- 38 pptv) vs. the control group (-17 +/- 15 pptv; P = 0.04). Lung disease in CF is accompanied by the subsistence of chronic bacterial infections. Sulfides are known to be produced by bacteria in various systems and were therefore the special target for this investigation. Our results suggest that breath sulfide content deserves attention as a noninvasive marker of respiratory colonization.
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Affiliation(s)
- M A Kamboures
- Department of Chemistry, University of California, Irvine, CA 92697-2025, USA
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12
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Hollande E, Salvador-Cartier C, Alvarez L, Fanjul M. Expression of a wild-type CFTR maintains the integrity of the biosynthetic/secretory pathway in human cystic fibrosis pancreatic duct cells. J Histochem Cytochem 2005; 53:1539-52. [PMID: 15956032 PMCID: PMC3957539 DOI: 10.1369/jhc.4a6587.2005] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The structural integrity of the Golgi complex is essential to its functions in the maturation, sorting, and transport of plasma membrane proteins. Previously, we demonstrated that in pancreatic duct CFPAC-1 cells, which express DeltaF508 CFTR (cystic fibrosis transmembrane conductance regulator), the intracellular trafficking of carbonic anhydrase IV (CA IV), a membrane protein involved in HCO(3)(-) secretion, was impaired. To determine whether these abnormalities were related to changes in the Golgi complex, we examined the ultrastructure and distribution of Golgi compartments with regard to the microtubule cytoskeleton in CFPAC-1 cells transfected or not with the wild-type CFTR. Ultrastructural and immunocytochemical analysis showed that in polarized CFPAC-1 cells, Golgi stacks were disconnected from one another and scattered throughout the cytoplasm. The colocalization of CA IV with markers of Golgi compartments indicated the ability of stacks to transfer this enzyme. This Golgi dispersal was associated with abnormal microtubule distribution and multiplicity of the microtubule-organizing centers (MTOCs). In reverted cells, the normalization of Golgi structure, microtubule distribution, and MTOC number was observed. These observations suggest that the entire biosynthetic/secretory pathway is disrupted in CFPAC-1 cells, which might explain the abnormal intracellular transport of CA IV. Taken together, these results point to the fact that the expression of DeltaF508 CFTR affects the integrity of the secretory pathway.
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Affiliation(s)
- Etienne Hollande
- Laboratoire de Biologie Cellulaire et Moléculaire des Epithéliums, Université Paul Sabatier, Toulouse, France.
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13
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Abstract
In many species the pancreatic duct epithelium secretes HCO3- ions at a concentration of around 140 mM by a mechanism that is only partially understood. We know that HCO3- uptake at the basolateral membrane is achieved by Na+-HCO3- cotransport and also by a H+-ATPase and Na+/H+ exchanger operating together with carbonic anhydrase. At the apical membrane, the secretion of moderate concentrations of HCO3- can be explained by the parallel activity of a Cl-/HCO3- exchanger and a Cl- conductance, either the cystic fibrosis transmembrane conductance regulator (CFTR) or a Ca2+-activated Cl- channel (CaCC). However, the sustained secretion of HCO3- into a HCO- -rich luminal fluid cannot be explained by conventional Cl-/HCO3- exchange. HCO3- efflux across the apical membrane is an electrogenic process that is facilitated by the depletion of intracellular Cl-, but it remains to be seen whether it is mediated predominantly by CFTR or by an electrogenic SLC26 anion exchanger.
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Affiliation(s)
- Martin C Steward
- Faculty of Life Sciences, University of Manchester, Manchester M13 9PT, United Kingdom.
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14
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Bonapace G, Waheed A, Shah GN, Sly WS. Chemical chaperones protect from effects of apoptosis-inducing mutation in carbonic anhydrase IV identified in retinitis pigmentosa 17. Proc Natl Acad Sci U S A 2004; 101:12300-5. [PMID: 15295099 PMCID: PMC514473 DOI: 10.1073/pnas.0404764101] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Carbonic anhydrase (CA) IV is a glycosylphosphotidylinositol-anchored enzyme highly expressed on the plasma face of microcapillaries and especially strongly expressed in the choriocapillaris of the human eye. In collaboration with scientists at the University of Cape Town (Rondebosch, South Africa), we recently showed that the R14W mutation in the signal sequence of CA IV, which they identified in patients with the retinitis pigmentosa (RP) 17 form of autosomal dominant RP, results in accumulation of unfolded protein in the endoplasmic reticulum (ER), leading to ER stress, the unfolded protein response, and apoptosis in a large fraction of transfected COS-7 cells expressing mutant, but not wild-type, CA IV. Here we present experiments showing that several well characterized CA inhibitors largely prevent the adverse effects of expressing R14W CA IV in transfected COS-7 cells. Specifically, CA inhibitors prevent the accelerated turnover of the mutant protein, the up-regulation of Ig-binding protein, double-stranded RNA-regulated protein kinase-like ER kinase, and CCAAT/enhancer-binding protein homologous protein (markers of the unfolded protein response and ER stress), the inhibition of production of other secretory proteins expressed from COS-7-transfecting plasmids, and the induction of apoptosis, all characteristics of transfected cells expressing R14W CA IV. Furthermore, treatment with 4-phenylbutyric acid, a nonspecific chemical chaperone used in other protein-folding disorders, also dramatically reduces the apoptosis-inducing effect of expressing R14W CA IV cDNA in transfected COS-7 cells. These experiments suggest a promising approach to treatment of RP17 that might delay the onset or possibly prevent this autosomal dominant form of RP.
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Affiliation(s)
- Giuseppe Bonapace
- Edward A. Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, St. Louis, MO 63104, USA
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15
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Fanjul M, Alvarez L, Salvador C, Gmyr V, Kerr-Conte J, Pattou F, Carter N, Hollande E. Evidence for a membrane carbonic anhydrase IV anchored by its C-terminal peptide in normal human pancreatic ductal cells. Histochem Cell Biol 2004; 121:91-9. [PMID: 14740223 DOI: 10.1007/s00418-003-0616-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/11/2003] [Indexed: 11/26/2022]
Abstract
The high concentration of HCO(3)(-) ions (150 mM) in the human pancreatic ducts raises the question of the membrane proteins responsible for their secretion in addition to the Cl(-)/HCO(3)(-) exchanger. In this study, we investigated the expression of carbonic anhydrase IV (CA IV), a possible candidate. Experiments were carried out on specimens of normal human pancreas obtained from brain-dead donors ( n=9) as well as on isolated human ductal cells. Two antibodies were generated: CA IV NH(2) antibody directed against the NH(2) terminal of human glycosyl phosphatidylinositol (GPI)-anchored CA IV and CA IV COOH antibody directed against the COOH terminal of the same protein before its association with a GPI in the rough endoplasmic reticulum. A 35-kDa CA IV was detected in the homogenates of human pancreas. Immunocytochemistry demonstrated the expression of CA IV in centroacinar cells and in intercalated, intralobular, and interlobular ductal cells. The immunoreactivity observed with the CA IV COOH antibody was mainly localized on luminal membranes of ductal cells. Treatment of purified plasma membranes with phosphatidylinositol-phospholipase C indicated that the CA IV expressed in pancreatic ducts was not GPI-anchored. Its detection in the same extracts by the CA IV COOH antibody indicated that it was anchored by a hydrophobic segment at the carboxy terminal. Taken together, these results suggest that normal human pancreatic ductal cells express a 35-kDa CA IV anchored in their luminal plasma membrane by a hydrophobic segment of the COOH terminus. In view of its localization and its mode of anchorage in luminal plasma membranes, this CA IV may participate in the maintenance of luminal pH.
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Affiliation(s)
- Marjorie Fanjul
- Laboratoire de Biologie Cellulaire et Moléculaire des Epithéliums (EA 3032), Université Paul Sabatier, 38 rue des 36 Ponts, 31400 Toulouse, France
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16
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Alvarez BV, Loiselle FB, Supuran CT, Schwartz GJ, Casey JR. Direct extracellular interaction between carbonic anhydrase IV and the human NBC1 sodium/bicarbonate co-transporter. Biochemistry 2003; 42:12321-9. [PMID: 14567693 DOI: 10.1021/bi0353124] [Citation(s) in RCA: 123] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Sodium/bicarbonate co-transporters (NBC) are crucial in the regulation of intracellular pH (pH(i)) and HCO(3)(-) metabolism. Electrogenic NBC1 catalyzes HCO(3)(-) fluxes in mammalian kidney, pancreas, and heart cells. Carbonic anhydrase IV (CAIV), which is also present in these tissues, is glycosylphosphatidyl inositol-anchored to the outer surface of the plasma membrane where it catalyzes the hydration-dehydration of CO(2)/HCO(3)(-). The physical and functional interactions of CAIV and NBC1 were investigated. NBC1 activity was measured by changes of pH(i) in NBC1-transfected HEK293 cells subjected to acid loads. Cotransfection of CAIV with NBC1 increased the rate of pH(i) recovery by 44 +/- 3%, as compared to NBC1-alone. In contrast, CAIV did not increase the functional activity of G767T-NBC1 (mutated on the fourth extracellular loop (EC4) of NBC1), and G767T-NBC1, unlike wild-type NBC1, did not interact with CAIV in glutathione-S-transferase pull-down assays. This indicates that G767 of NBC1 is directly involved in CAIV interaction. NBC1-mediated pH(i) recovery rate after acid load was inhibited by 40 +/- 7% when coexpressed with the inactive human CAII mutant, V143Y. V143Y CAII competes with endogenous CAII for interaction with NBC1 at the inner surface of the plasma membrane, which indicates that NBC1/CAII interaction is needed for full pH(i) recovery activity. We conclude that CAIV binds EC4 of NBC1, and this interaction is essential for full NBC1 activity. The tethering of CAII and CAIV close to the NBC1 HCO(3)(-) transport site maximizes the transmembrane HCO(3)(-) gradient local to NBC1 and thereby activates the transport rate.
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Affiliation(s)
- Bernardo V Alvarez
- Department of Physiology, University of Alberta, Edmonton, Alberta, Canada T6G 2H7
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17
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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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