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Scull CE, Luo M, Jennings S, Taylor CM, Wang G. Cftr deletion in mouse epithelial and immune cells differentially influence the intestinal microbiota. Commun Biol 2022; 5:1130. [PMID: 36289287 PMCID: PMC9605958 DOI: 10.1038/s42003-022-04101-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Accepted: 10/11/2022] [Indexed: 11/25/2022] Open
Abstract
Cystic fibrosis (CF) is a life-threatening genetic disorder, caused by mutations in the CF transmembrane-conductance regulator gene (cftr) that encodes CFTR, a cAMP-activated chloride and bicarbonate channel. Clinically, CF lung disease dominates the adult patient population. However, its gastrointestinal illness claims the early morbidity and mortality, manifesting as intestinal dysbiosis, inflammation and obstruction. As CF is widely accepted as a disease of epithelial dysfunction, it is unknown whether CFTR loss-of-function in immune cells contributes to these clinical outcomes. Using cftr genetic knockout and bone marrow transplantation mouse models, we performed 16S rRNA gene sequencing of the intestinal microbes. Here we show that cftr deletion in both epithelial and immune cells collectively influence the intestinal microbiota. However, the immune defect is a major factor determining the dysbiosis in the small intestine, while the epithelial defect largely influences that in the large intestine. This finding revises the current concept by suggesting that CF epithelial defect and immune defect play differential roles in CF intestinal disease.
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Affiliation(s)
- Callie E Scull
- Department of Microbiology, Immunology and Parasitology, Louisiana State University Health Sciences Center, New Orleans, LA, USA
| | - Meng Luo
- Department of Microbiology, Immunology and Parasitology, Louisiana State University Health Sciences Center, New Orleans, LA, USA
| | - Scott Jennings
- Department of Microbiology, Immunology and Parasitology, Louisiana State University Health Sciences Center, New Orleans, LA, USA
| | - Christopher M Taylor
- Department of Microbiology, Immunology and Parasitology, Louisiana State University Health Sciences Center, New Orleans, LA, USA
| | - Guoshun Wang
- Department of Microbiology, Immunology and Parasitology, Louisiana State University Health Sciences Center, New Orleans, LA, USA.
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Vásquez Cachay ME, Gomez EP, Rodríguez Gutiérrez JL, Lira Mejía B, Pérez NF, Zanuzzi CN, Barbeito C. Paneth Cell Identification in the Small Intestine of Guinea Pig Offsprings (Cavia porcellus). Anat Rec (Hoboken) 2014; 297:856-63. [DOI: 10.1002/ar.22890] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2013] [Accepted: 01/08/2014] [Indexed: 01/21/2023]
Affiliation(s)
- María Elith Vásquez Cachay
- Animal Physiology Laboratory; Veterinary Medicine School; National University of San Marcos; San Borja Lima Perú
| | - Erika Pebe Gomez
- Animal Physiology Laboratory; Veterinary Medicine School; National University of San Marcos; San Borja Lima Perú
| | - José Luis Rodríguez Gutiérrez
- Experimental Centre IVITA-El Mantaro; Veterinary Medicine School; National University of San Marcos; San Borja Lima Perú
| | - Boris Lira Mejía
- Animal Physiology Laboratory; Veterinary Medicine School; National University of San Marcos; San Borja Lima Perú
| | - Néstor Falcón Pérez
- Veterinary and Zootecnic Medicine School; Cayetano Heredia University (UPCH); San Martin de Porres Lima Perú
| | - Carolina Natalia Zanuzzi
- Department of Histology and Embryology; School of Veterinary Sciences, National University of La Plata; La Plata Buenos Aires Argentina
- National Scientific and Technical Research Council (CONICET-CCT La Plata); Buenos Aires Argentina
| | - Claudio Barbeito
- Department of Histology and Embryology; School of Veterinary Sciences, National University of La Plata; La Plata Buenos Aires Argentina
- National Scientific and Technical Research Council (CONICET-CCT La Plata); Buenos Aires Argentina
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Alexander SPH, Benson HE, Faccenda E, Pawson AJ, Sharman JL, Catterall WA, Spedding M, Peters JA, Harmar AJ. The Concise Guide to PHARMACOLOGY 2013/14: ion channels. Br J Pharmacol 2013; 170:1607-51. [PMID: 24528239 PMCID: PMC3892289 DOI: 10.1111/bph.12447] [Citation(s) in RCA: 225] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The Concise Guide to PHARMACOLOGY 2013/14 provides concise overviews of the key properties of over 2000 human drug targets with their pharmacology, plus links to an open access knowledgebase of drug targets and their ligands (www.guidetopharmacology.org), which provides more detailed views of target and ligand properties. The full contents can be found at http://onlinelibrary.wiley.com/doi/10.1111/bph.12444/full. Ion channels are one of the seven major pharmacological targets into which the Guide is divided, with the others being G protein-coupled receptors, ligand-gated ion channels, catalytic receptors, nuclear hormone receptors, transporters and enzymes. These are presented with nomenclature guidance and summary information on the best available pharmacological tools, alongside key references and suggestions for further reading. A new landscape format has easy to use tables comparing related targets. It is a condensed version of material contemporary to late 2013, which is presented in greater detail and constantly updated on the website www.guidetopharmacology.org, superseding data presented in previous Guides to Receptors and Channels. It is produced in conjunction with NC-IUPHAR and provides the official IUPHAR classification and nomenclature for human drug targets, where appropriate. It consolidates information previously curated and displayed separately in IUPHAR-DB and the Guide to Receptors and Channels, providing a permanent, citable, point-in-time record that will survive database updates.
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Affiliation(s)
- Stephen PH Alexander
- School of Life Sciences, University of Nottingham Medical SchoolNottingham, NG7 2UH, UK
- *
Author for correspondence;
| | - Helen E Benson
- The University/BHF Centre for Cardiovascular Science, University of EdinburghEdinburgh, EH16 4TJ, UK
| | - Elena Faccenda
- The University/BHF Centre for Cardiovascular Science, University of EdinburghEdinburgh, EH16 4TJ, UK
| | - Adam J Pawson
- The University/BHF Centre for Cardiovascular Science, University of EdinburghEdinburgh, EH16 4TJ, UK
| | - Joanna L Sharman
- The University/BHF Centre for Cardiovascular Science, University of EdinburghEdinburgh, EH16 4TJ, UK
| | - William A Catterall
- University of Washington, School of Medicine, Department of PharmacologyBox 357280, Seattle, WA 98195-7280, USA
| | | | - John A Peters
- Neuroscience Division, Medical Education Institute, Ninewells Hospital and Medical School, University of DundeeDundee, DD1 9SY, UK
| | - Anthony J Harmar
- The University/BHF Centre for Cardiovascular Science, University of EdinburghEdinburgh, EH16 4TJ, UK
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Figueiras-Fierro D, Acevedo JJ, Martínez-López P, Escoffier J, Sepúlveda FV, Balderas E, Orta G, Visconti PE, Darszon A. Electrophysiological evidence for the presence of cystic fibrosis transmembrane conductance regulator (CFTR) in mouse sperm. J Cell Physiol 2013; 228:590-601. [PMID: 22833409 DOI: 10.1002/jcp.24166] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2011] [Accepted: 07/17/2012] [Indexed: 01/25/2023]
Abstract
Mammalian sperm must undergo a maturational process, named capacitation, in the female reproductive tract to fertilize the egg. Sperm capacitation is regulated by a cAMP/protein kinase A (PKA) pathway and involves increases in intracellular Ca(2+), pH, Cl(-), protein tyrosine phosphorylation, and in mouse and some other mammals a membrane potential hyperpolarization. The cystic fibrosis transmembrane conductance regulator (CFTR), a Cl(-) channel modulated by cAMP/PKA and ATP, was detected in mammalian sperm and proposed to modulate capacitation. Our whole-cell patch-clamp recordings from testicular mouse sperm now reveal a Cl(-) selective component to membrane current that is ATP-dependent, stimulated by cAMP, cGMP, and genistein (a CFTR agonist, at low concentrations), and inhibited by DPC and CFTR(inh) -172, two well-known CFTR antagonists. Furthermore, the Cl(-) current component activated by cAMP and inhibited by CFTR(inh) -172 is absent in recordings on testicular sperm from mice possessing the CFTR ΔF508 loss-of-function mutation, indicating that CFTR is responsible for this component. A Cl(-) selective like current component displaying CFTR characteristics was also found in wild type epididymal sperm bearing the cytoplasmatic droplet. Capacitated sperm treated with CFTR(inh) -172 undergo a shape change, suggesting that CFTR is involved in cell volume regulation. These findings indicate that functional CFTR channels are present in mouse sperm and their biophysical properties are consistent with their proposed participation in capacitation.
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Affiliation(s)
- Dulce Figueiras-Fierro
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca Morelos, Mexico
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7
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Kida H, Miyoshi T, Manabe K, Takahashi N, Konno T, Ueda S, Chiba T, Shimizu T, Okada Y, Morishima S. Roles of aquaporin-3 water channels in volume-regulatory water flow in a human epithelial cell line. J Membr Biol 2009; 208:55-64. [PMID: 16596446 DOI: 10.1007/s00232-005-0819-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2005] [Revised: 11/10/2005] [Indexed: 10/24/2022]
Abstract
Membrane water transport is an essential event not only in the osmotic cell volume change but also in the subsequent cell volume regulation. Here we investigated the route of water transport involved in the regulatory volume decrease (RVD) that occurs after osmotic swelling in human epithelial Intestine 407 cells. The diffusion water permeability coefficient (Pd) measured by NMR under isotonic conditions was much smaller than the osmotic water permeability coefficient (Pf) measured under an osmotic gradient. Temperature dependence of Pf showed the Arrhenius activation energy (Ea) of a low value (1.6 kcal/mol). These results indicate an involvement of a facilitated diffusion mechanism in osmotic water transport. A mercurial water channel blocker (HgCl(2)) diminished the Pf value. A non-mercurial sulfhydryl reagent (MMTS) was also effective. These blockers of water channels suppressed the RVD. RT-PCR and immunocytochemistry demonstrated predominant expression of AQP3 water channel in this cell line. Downregulation of AQP3 expression induced by treatment with antisense oligodeoxynucleotides was found to suppress the RVD response. Thus, it is concluded that AQP3 water channels serve as an essential pathway for volume-regulatory water transport in, human epithelial cells.
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Affiliation(s)
- H Kida
- Department of Cell Physiology, National Institute for Physiological Sciences, Okazaki 444-8585, Japan
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9
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Nissant A, Lourdel S, Baillet S, Paulais M, Marvao P, Teulon J, Imbert-Teboul M. Heterogeneous distribution of chloride channels along the distal convoluted tubule probed by single-cell RT-PCR and patch clamp. Am J Physiol Renal Physiol 2004; 287:F1233-43. [PMID: 15280163 DOI: 10.1152/ajprenal.00155.2004] [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] [Indexed: 11/22/2022] Open
Abstract
The distal convoluted tubule (DCT) is a heterogeneous segment subdivided into early (DCT1) and late (DCT2) parts, depending on the distribution of various transport systems. We do not have an exhaustive picture of the Cl−channels on the basolateral side: the presence of ClC-K2 channels is generally accepted, whereas that of ClC-K1 remains controversial. We used here single-cell RT-PCR and patch clamp to probe Cl−channel heterogeneity in microdissected mouse DCT at the molecular and functional levels. Our findings show that 63% of the DCT cells express ClC-K2 mRNA, either alone (type 1 cells: 47 and 23% in DCT1 and DCT2, respectively), or combined with ClC-K1, mostly in DCT2 (type 2 cells: 33%), but 37% of DCT1 and DCT2 cells do not express any ClC-K. Patch-clamp experiments revealed that a Cl−channel, with 9-pS conductance and Cl−> NO3−= Br−anion selectivity sequence, is present in the DCT1 and DCT2 basolateral membranes (87 and 71% of the patches, respectively). This dominant channel is likely to be ClC-K2 in type 1 cells. In type 2 cells, it could be ClC-K2 and/or ClC-K1 homodimers, but also ClC-K1/ClC-K2 heterodimers, or a mixture of all combinations. A second, distinct Cl−channel (13% of DCT1 patches, 29% of DCT2 patches) also displayed 9-pS conductance but had a completely different anion selectivity (I−> NO3−> Br−> Cl−), which was not compatible with that of the ClC-Ks. This indicates that a Cl−channel that is unlikely to belong to the ClC family may also be involved in Cl−absorption in the DCT2.
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Affiliation(s)
- Antoine Nissant
- Centre National de la Recherche Scientifique, Université Pierre et Marie Curie, UMR 7134, Institut des Cordeliers, 15 rue de l'Ecole de Médecine, 75270 Paris Cedex 06, France
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Konturek PC, Konturek SJ, Hahn EG. Duodenal alkaline secretion: its mechanisms and role in mucosal protection against gastric acid. Dig Liver Dis 2004; 36:505-12. [PMID: 15334769 DOI: 10.1016/j.dld.2004.03.008] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Duodenal mucosa, especially its proximal portion, is exposed to intermittent pulses of gastric acid (H+). This review summarises the mechanisms of duodenal bicarbonate (HCO3-) secretion and their role in protecting duodenal epithelium against gastric H+. Duodenal epithelium is a leaky barrier against gastric H+, which diffuses into duodenocytes, but fails to damage them due to: (a) an enhanced expression of cyclooxygenase, producing protective prostaglandins and expression of nitric oxide synthase, releasing nitric oxide, both stimulating duodenal HCO3- secretion and (b) the release of several neurotransmitters also stimulating HCO3- secretion such as vasoactive intestinal peptide, pituitary adenylate cyclase-activating polypeptide, acetylcholine and melatonin. At the apical duodenocyte membrane, several HCO3-/Cl- anion exchangers operate in response to luminal H+ to extrude HCO3- into duodenal lumen. In baso-lateral duodenocyte membrane, both non-electrogenic and electrogenic Na+-HCO3- cotransporters are activated after exposure of duodenum to gastric H+, causing inward movement of HCO3- from extracellular fluid to duodenocytes. There are also at least three Na+/H+ exchangers, eliminating H+ which diffused into these cells. The Helicobacter pylori infection with gastric metaplasia in the duodenum and bacterium inoculation results in the inhibition of HCO3- secretion by its endogenous inhibitor dimethyl arginine, resulting in ulcerogenesis.
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Affiliation(s)
- P C Konturek
- First Department of Medicine, University Erlangen-Nuernberg. Erlangen, Germany
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11
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Manabe KI, Shimizu T, Morishima S, Okada Y. Regulatory volume increase after secretory volume decrease in colonic epithelial cells under muscarinic stimulation. Pflugers Arch 2004; 448:596-604. [PMID: 15243741 DOI: 10.1007/s00424-004-1301-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2004] [Accepted: 05/19/2004] [Indexed: 10/26/2022]
Abstract
To address the question of whether colonic secretory cells change their volume in response to carbachol (CCh) stimulation and, if so, the mechanisms involved therein, we used two-photon laser scanning microscopy to measure the volume of individual epithelial cells in the fundus region of crypts isolated from the guinea-pig distal colon. We also measured the volume of human colonic epithelial T84 cells using an electronic sizing technique. Both types of colonocytes responded to stimulation by CCh with shrinkage and then underwent a regulatory volume increase (RVI), even during continued stimulation by CCh. The secretory volume decrease (SVD) induced by CCh was antagonized by atropine, BAPTA loading and niflumic acid, a blocker of Ca(2+)-activated Cl(-) channels. An increase in the intracellular free [Ca(2+)] was observed with fura-2 during these volume responses to CCh. Removal of all Na(+) or K(+) or of most of the Cl(-) from the extracellular solution abolished the RVI, but not the preceding SVD. The RVI, but not the preceding SVD, was abolished by bumetanide, a blocker of the Na(+)-K(+)-2Cl(-) cotransporter. We conclude that guinea-pig crypt colonocytes and human T84 cells exhibit a cytosolic Ca(2+)-dependent SVD and undergo a subsequent RVI that is dependent on the operation of Na(+)-K(+)-2Cl(-) cotransporters.
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Affiliation(s)
- Ken-ichi Manabe
- Department of Cell Physiology, National Institute for Physiological Sciences, Myodaiji-cho, 444-8585 Okazaki, Japan
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12
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Kogan I, Ramjeesingh M, Li C, Kidd JF, Wang Y, Leslie EM, Cole SPC, Bear CE. CFTR directly mediates nucleotide-regulated glutathione flux. EMBO J 2003; 22:1981-9. [PMID: 12727866 PMCID: PMC156066 DOI: 10.1093/emboj/cdg194] [Citation(s) in RCA: 159] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Studies have shown that expression of cystic fibrosis transmembrane conductance regulator (CFTR) is associated with enhanced glutathione (GSH) efflux from airway epithelial cells, implicating a role for CFTR in the control of oxidative stress in the airways. To define the mechanism underlying CFTR-associated GSH flux, we studied wild-type and mutant CFTR proteins expressed in Sf9 membranes, as well as purified and reconstituted CFTR. We show that CFTR-expressing membrane vesicles mediate nucleotide-activated GSH flux, which is disrupted in the R347D pore mutant, and in the Walker A K464A and K1250A mutants. Further, we reveal that purified CFTR protein alone directly mediates nucleotide-dependent GSH flux. Interestingly, although ATP supports GSH flux through CFTR, this activity is enhanced in the presence of the non-hydrolyzable ATP analog AMP-PNP. These findings corroborate previous suggestions that CFTR pore properties can vary with the nature of the nucleotide interaction. In conclusion, our data demonstrate that GSH flux is an intrinsic function of CFTR and prompt future examination of the role of this function in airway biology in health and disease.
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Affiliation(s)
- Ilana Kogan
- Hospital for Sick Children, Department of Physiology, University of Toronto, Toronto, Ontario M5G 1X8
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13
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Abstract
AIM This review describes molecular and functional properties of the following Cl- channels: the ClC family of voltage-dependent Cl- channels, the cAMP-activated transmembrane conductance regulator (CFTR), Ca2+ activated Cl- channels (CaCC) and volume-regulated anion channels (VRAC). If structural data are available, their relationship with the function of Cl- channels will be discussed. We also describe shortly some recently discovered channels, including high conductance Cl- channels and the family of bestrophins. We illustrate the growing physiological importance of these channels in the plasma membrane and in intracellular membranes, including their involvement in transepithelial transport, pH regulation of intracellular organelles, regulation of excitability and volume regulation. Finally, we discuss the role of Cl- channels in various diseases and describe the pathological phenotypes observed in knockout mice models.
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Affiliation(s)
- B Nilius
- KU Leuven, Laboratorium voor Fysiologie, Campus Gasthuisberg, Leuven, Belgium
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14
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Yeger H, Pan J, Fu XW, Bear C, Cutz E. Expression of CFTR and Cl(-) conductances in cells of pulmonary neuroepithelial bodies. Am J Physiol Lung Cell Mol Physiol 2001; 281:L713-21. [PMID: 11504700 DOI: 10.1152/ajplung.2001.281.3.l713] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The pulmonary neuroendocrine cell system comprises solitary neuroendocrine cells and clusters of innervated cells or neuroepithelial bodies (NEBs). NEBs figure prominently during the perinatal period when they are postulated to be involved in physiological adaptation to air breathing. Previous studies have documented hyperplasia of NEBs in cystic fibrosis (CF) lungs and increased neuropeptide (bombesin) content produced by these cells, possibly secondary to chronic hypoxia related to CF lung disease. However, little is known about the role of NEBs in the pathogenesis of CF lung disease. In the present study, using a panel of cystic fibrosis transmembrane conductance regulator (CFTR)-specific antibodies and confocal microscopy in combination with RT-PCR, we demonstrate expression of CFTR message and protein in NEB cells of rabbit neonatal lungs. NEB cells expressed CFTR along with neuroendocrine markers. Confocal microscopy established apical membrane localization of the CFTR protein in NEB cells. Cl(-) conductances corresponding to functional CFTR were demonstrated in NEB cells in a fresh lung slice preparation. Our findings suggest that NEBs, and related neuroendocrine mechanisms, likely play a role in the pathogenesis of CF lung disease, including the early stages before establishment of chronic infection and chronic lung disease.
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Affiliation(s)
- H Yeger
- Division of Pathology, Department of Pediatric Laboratory Medicine and Pathobiology, Research Institute and Hospital for Sick Children, Toronto, Ontario, Canada M5G 1X8.
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Leung GP, Gong XD, Cheung KH, Cheng-Chew SB, Wong PY. Expression of cystic fibrosis transmembrane conductance regulator in rat efferent duct epithelium. Biol Reprod 2001; 64:1509-15. [PMID: 11319159 DOI: 10.1093/biolreprod/64.5.1509] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The expression of cystic fibrosis transmembrane conductance regulator (CFTR) was studied in rat efferent ducts. Under whole-cell patch-clamp condition, efferent duct cells responded to intracellular cAMP with a rise in inward current. The cAMP-activated current exhibited a linear I-V relationship and time- and voltage-independent characteristics. The current was inhibited by the Cl(-) channel blocker diphenylamine 2,2'-dicarboxylic acid (DPC) in a voltage-dependent manner and reversed at 24 +/- 0.5 mV, close to the equilibrium potential for Cl(-) (30 mV), suggesting that the current was Cl(-) selective. The cAMP-activated current displayed a permeability sequence of Br(-) > Cl(-) > I(-). Short-circuit current measurement in cultured rat efferent duct epithelia also revealed a cAMP-activated inward current inhibitable by DPC. These electrophysiological properties of the cAMP-activated Cl(-) conductance in the efferent duct were consistent with those reported for CFTR. In support of the functional studies, reverse transcription polymerase chain reaction revealed the presence of CFTR message in cultured efferent duct epithelium. Immunohistochemical studies in intact rats also demonstrated CFTR protein at the apical membrane of the principal cells of efferent duct. CFTR may play a role in modulating fluid transport in the efferent duct.
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Affiliation(s)
- G P Leung
- Department of Physiology, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong, China
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Daniel EE, Kwan CY, Janssen L. Pharmacological techniques for the in vitro study of intestinal smooth muscles. J Pharmacol Toxicol Methods 2001; 45:141-58. [PMID: 11687381 DOI: 10.1016/s1056-8719(01)00131-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
MESH Headings
- Animals
- Dose-Response Relationship, Drug
- Electric Stimulation
- Humans
- In Vitro Techniques
- Intestine, Large/drug effects
- Intestine, Large/innervation
- Intestine, Large/physiology
- Intestine, Small/drug effects
- Intestine, Small/innervation
- Intestine, Small/physiology
- Muscle Contraction/drug effects
- Muscle Contraction/physiology
- Muscle, Smooth/drug effects
- Muscle, Smooth/innervation
- Muscle, Smooth/physiology
- Xenobiotics/pharmacology
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Affiliation(s)
- E E Daniel
- Department of Medicine, Faculty of Health Sciences, McMaster University, Hamilton, Ontario L8N 3Z5, Canada
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Praetorius J, Hager H, Nielsen S, Aalkjaer C, Friis UG, Ainsworth MA, Johansen T. Molecular and functional evidence for electrogenic and electroneutral Na(+)-HCO(3)(-) cotransporters in murine duodenum. Am J Physiol Gastrointest Liver Physiol 2001; 280:G332-43. [PMID: 11171615 DOI: 10.1152/ajpgi.2001.280.3.g332] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Inward Na(+)-HCO(3)(-) cotransport has previously been demonstrated in acidified duodenal epithelial cells, but the identity and localization of the mRNAs and proteins involved have not been determined. The molecular expression and localization of Na(+)-HCO(3)(-) cotransporters (NBCs) were studied by RT-PCR, sequence analysis, and immunohistochemistry. By fluorescence spectroscopy, the intracellular pH (pH(i)) was recorded in suspensions of isolated murine duodenal epithelial cells loaded with 2',7'-bis(2-carboxyethyl)-5(6)-carboxyfluorescein. Proximal duodenal epithelial cells expressed mRNA encoding two electrogenic NBC1 isoforms and the electroneutral NBCn1. Both NBC1 and NBCn1 were localized to the basolateral membrane of proximal duodenal villus cells, whereas the crypt cells did not label with the anti-NBC antibodies. DIDS or removal of extracellular Cl(-) increased pH(i), whereas an acidification was observed on removal of Na(+) or both Na(+) and Cl(-). The effects of inhibitors and ionic dependence of acid/base transporters were consistent with both inward and outward Na(+)-HCO(3)(-) cotransport. Hence, we propose that NBCs are involved in both basolateral electroneutral HCO(3)(-) transport as well as basolateral electrogenic HCO(3)(-) transport in proximal duodenal villus cells.
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Affiliation(s)
- J Praetorius
- Department of Physiology and Pharmacology, Institute of Medical Biology, University of Southern Denmark-Odense University, Winsloewparken 21, DK-5000 Odense C, Denmark.
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Schwiehert EM, Rozmahel R. Chapter 6 The cystic fibrosis transmembrane conductance regulator in the gastrointestinal system. CURRENT TOPICS IN MEMBRANES 2000. [DOI: 10.1016/s1063-5823(00)50008-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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