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Berczeli O, Vizvári E, Katona M, Török D, Szalay L, Rárosi F, Németh I, Rakonczay Z, Hegyi P, Ding C, Tóth-Molnár E. Novel Insight Into the Role of CFTR in Lacrimal Gland Duct Function in Mice. Invest Ophthalmol Vis Sci 2018; 59:54-62. [PMID: 29305607 PMCID: PMC5756044 DOI: 10.1167/iovs.17-22533] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Purpose The role of cystic fibrosis transmembrane conductance regulator (CFTR) in lacrimal gland (LG) function has only recently received some attention, mainly from our group. In the present study, we investigated the potential changes of LG pathology, tear secretion, ocular surface integrity, and fluid secretion in isolated LG ducts from CFTR knockout (KO) mice. Methods Tear production and ocular surface integrity were investigated in anesthetized wild-type (WT) and KO mice using cotton threads and fluorescein staining, respectively. Immunofluorescence was used to localize CFTR protein in the LGs. Ductal fluid secretions evoked by forskolin (10 μM); cell-permeable cAMP analogue (8-bromo cAMP, 100 μM); or carbachol (100 μM) were measured in isolated LG ducts using video-microscopy. Intracellular Ca2+ homeostasis underlying carbachol stimulation was investigated with microfluorometry. Results Significant decrease in tear secretion and impaired ocular surface integrity were observed in KO mice. Immunofluorescence demonstrated the predominant presence of CFTR protein in the apical membranes of the duct cells from WT mice. Continuous fluid secretion was evoked by forskolin and 8-bromo cAMP in LG ducts from WT mice, while no secretory response was observed in ducts from KO mice. Carbachol caused similar secretory responses in ducts from WT and KO animals without significant differences in cytosolic Ca2+ signaling. Conclusions Our results suggest the important role of CFTR in LG ductal secretion and in the maintenance of ocular surface integrity, suggesting that CFTR may be a promising target of novel therapeutic approaches in the treatment of dry eye.
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Affiliation(s)
- Orsolya Berczeli
- Department of Ophthalmology, University of Szeged, Szeged, Hungary
| | - Eszter Vizvári
- Department of Ophthalmology, University of Szeged, Szeged, Hungary
| | - Máté Katona
- 1st Department of Internal Medicine, University of Szeged, Szeged, Hungary
| | - Dénes Török
- Department of Anatomy, University of Szeged, Szeged, Hungary
| | - László Szalay
- Department of Ophthalmology, University of Szeged, Szeged, Hungary
| | - Ferenc Rárosi
- Department of Medical Physics and Informatics, University of Szeged, Szeged, Hungary
| | - István Németh
- Department of Dermatology and Allergology, University of Szeged, Szeged, Hungary
| | - Zoltán Rakonczay
- 1st Department of Internal Medicine, University of Szeged, Szeged, Hungary.,Department of Pathophysiology, University of Szeged, Szeged, Hungary
| | - Péter Hegyi
- Institute for Translational Medicine and First Department of Medicine, University of Pécs, Pécs, Hungary.,MTA-SZTE Translational Gastroenterology Research Group, Szeged, Hungary
| | - Chuanqing Ding
- Pharmacology & Pharmaceutical Sciences, Ophthalmology, University of Southern California, Los Angeles, California, United States
| | - Edit Tóth-Molnár
- Department of Ophthalmology, University of Szeged, Szeged, Hungary.,Department of Pharmacology and Pharmacotherapy, University of Szeged, Szeged, Hungary
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Felix CM, Lee S, Levin MH, Verkman AS. Pro-Secretory Activity and Pharmacology in Rabbits of an Aminophenyl-1,3,5-Triazine CFTR Activator for Dry Eye Disorders. Invest Ophthalmol Vis Sci 2017; 58:4506-4513. [PMID: 28873176 PMCID: PMC5584707 DOI: 10.1167/iovs.17-22525] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Purpose Pharmacological activation of ocular surface cystic fibrosis transmembrane conductance regulator (CFTR) chloride channels is a potential pro-secretory approach to treat dry eye disorders. We previously reported the discovery of aminophenyl-1,3,5-triazines, one of which, N-methyl-N-phenyl-6-(2,2,3,3-tetrafluoropropoxy)-1,3,5-triazine-2,4-diamine (herein called CFTRact-K267), fully activated human wildtype CFTR with EC50 ∼ 30 nM and increased tear volume for 8 hours in mice. Here, functional and pharmacological studies of CFTRact-K267 were done in adult New Zealand white rabbits. Methods CFTR chloride conductance was measured in vivo by ocular surface potential differences and in ex vivo conjunctiva by short-circuit current. Tear volume was measured by the Schirmer tear test II and CFTRact-K267 pharmacokinetics and tissue distribution by liquid chromatography/mass spectrometry. Toxicity profile was studied for 28 days with twice-daily topical administration. Results Electrophysiological measurements in vivo and in ex vivo conjunctiva demonstrated CFTR activation by CFTRact-K267. A single topical dose of 3 nmol CFTRact-K267 increased tear production by >5 mm for 9 hours by the Schirmer tear test, with predicted therapeutic concentrations maintained in tear fluid. No tachyphylaxis was seen following 28-day twice-daily administration, and changes were not observed in corneal surface integrity or thickness, intraocular pressure, or ocular histology. At day 28, CFTRact-K267 was concentrated in the cornea and conjunctiva and was not detectable in blood or peripheral organs. Conclusions These studies support the development of CFTRact-K267 as a pro-secretory therapy for dry eye disorders.
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Affiliation(s)
- Christian M Felix
- Departments of Medicine and Physiology, University of California, San Francisco, California, United States
| | - Sujin Lee
- Departments of Medicine and Physiology, University of California, San Francisco, California, United States
| | - Marc H Levin
- Department of Ophthalmology, Palo Alto Medical Foundation, Palo Alto, California, United States
| | - Alan S Verkman
- Departments of Medicine and Physiology, University of California, San Francisco, California, United States
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Li S, Kim E, Bonanno JA. Fluid transport by the cornea endothelium is dependent on buffering lactic acid efflux. Am J Physiol Cell Physiol 2016; 311:C116-26. [PMID: 27225657 PMCID: PMC4967133 DOI: 10.1152/ajpcell.00095.2016] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2016] [Accepted: 05/17/2016] [Indexed: 11/22/2022]
Abstract
Maintenance of corneal hydration is dependent on the active transport properties of the corneal endothelium. We tested the hypothesis that lactic acid efflux, facilitated by buffering, is a component of the endothelial fluid pump. Rabbit corneas were perfused with bicarbonate-rich (BR) or bicarbonate-free (BF) Ringer of varying buffering power, while corneal thickness was measured. Perfusate was collected and analyzed for lactate efflux. In BF with no added HEPES, the maximal corneal swelling rate was 30.0 ± 4.1 μm/h compared with 5.2 ± 0.9 μm/h in BR. Corneal swelling decreased directly with [HEPES], such that with 60 mM HEPES corneas swelled at 7.5 ± 1.6 μm/h. Perfusate [lactate] increased directly with [HEPES]. Similarly, reducing the [HCO3 (-)] increased corneal swelling and decreased lactate efflux. Corneal swelling was inversely related to Ringer buffering power (β), whereas lactate efflux was directly related to β. Ouabain (100 μM) produced maximal swelling and reduction in lactate efflux, whereas carbonic anhydrase inhibition and an monocarboxylic acid transporter 1 inhibitor produced intermediate swelling and decreases in lactate efflux. Conversely, 10 μM adenosine reduced the swelling rate to 4.2 ± 0.8 μm/h and increased lactate efflux by 25%. We found a strong inverse relation between corneal swelling and lactate efflux (r = 0.98, P < 0.0001). Introducing lactate in the Ringer transiently increased corneal thickness, reaching a steady state (0 ± 0.6 μm/h) within 90 min. We conclude that corneal endothelial function does not have an absolute requirement for bicarbonate; rather it requires a perfusing solution with high buffering power. This facilitates lactic acid efflux, which is directly linked to water efflux, indicating that lactate flux is a component of the corneal endothelial pump.
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Affiliation(s)
- Shimin Li
- School of Optometry, Indiana University, Bloomington, Indiana
| | - Edward Kim
- School of Optometry, Indiana University, Bloomington, Indiana
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Adijanto J, Philp NJ. The SLC16A family of monocarboxylate transporters (MCTs)--physiology and function in cellular metabolism, pH homeostasis, and fluid transport. CURRENT TOPICS IN MEMBRANES 2012. [PMID: 23177990 DOI: 10.1016/b978-0-12-394316-3.00009-0] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The SLC16A family of monocarboxylate transporters (MCTs) is composed of 14 members. MCT1 through MCT4 (MCTs 1-4) are H(+)-coupled monocarboxylate transporters, MCT8 and MCT10 transport thyroid hormone and aromatic amino acids, while the substrate specificity and function of other MCTs have yet to be determined. The focus of this review is on MCTs 1-4 because their role in lactate transport is intrinsically linked to cellular metabolism in various biological systems, including skeletal muscle, brain, retina, and testis. Although MCTs 1-4 all transport lactate, they differ in their transport kinetics and vary in tissue and subcellular distribution, where they facilitate "lactate-shuttling" between glycolytic and oxidative cells within tissues and across blood-tissue barriers. However, the role of MCTs 1-4 is not confined to cellular metabolism. By interacting with bicarbonate transport proteins and carbonic anhydrases, MCTs participate in the regulation of pH homeostasis and fluid transport in renal proximal tubule and corneal endothelium, respectively. Here, we provide a comprehensive review of MCTs 1-4, linking their cellular distribution to their functions in various parts of the human body, so that we can better understand the physiological roles of MCTs at the systemic level.
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Affiliation(s)
- Jeffrey Adijanto
- Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, PA, USA.
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Nguyen TT, Bonanno JA. Bicarbonate, NBCe1, NHE, and carbonic anhydrase activity enhance lactate-H+ transport in bovine corneal endothelium. Invest Ophthalmol Vis Sci 2011; 52:8086-93. [PMID: 21896839 DOI: 10.1167/iovs.11-8086] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE To identify and localize the monocarboxylate transporters (MCTs) expressed in bovine corneal endothelial cells (BCEC) and to test the hypothesis that buffering contributed by HCO(3)(-), sodium bicarbonate cotransporter (NBCe1), sodium hydrogen exchanger (NHE), and carbonic anhydrase (CA) activity facilitates lactate flux. METHODS MCT1-4 expression was screened by RT-PCR, Western blot analysis, and immunofluorescence. Endogenous lactate efflux and/or pH(i) were measured in BCEC in HCO(3)(-)-free or HCO(3)(-)-rich Ringer, with and without niflumic acid (MCT inhibitor), acetazolamide (ACTZ, a CA inhibitor), 5-(N-Ethyl-N-isopropyl)amiloride (EIPA) (Na(+)/H(+) exchange blocker), disodium 4,4'-diisothiocyanatostilbene-2,2'-disulfonate (DIDS; anion transport inhibitor), or with NBCe1-specific small interfering (si) RNA-treated cells. RESULTS MCT1, 2, and 4 are expressed in BCEC. MCT1 was localized to the lateral membrane, MCT2 was lateral and apical, while MCT4 was apical. pH(i) measurements showed significant lactate-induced cell acidification (LIA) in response to 20-second pulses of lactate. Incubation with niflumic acid significantly reduced the rate of pHi change (dpH(i)/dt) and lactate-induced cell acidification. EIPA inhibited alkalinization after lactate removal. Lactate-dependent proton flux was significantly greater in the presence of HCO(3)(-) but was reduced by ACTZ. Efflux of endogenously produced lactate was significantly faster in the presence of HCO(3)(-), was greater on the apical surface, was reduced on the apical side by ACTZ, as well as on the apical and basolateral side by NBCe1-specific siRNA, DIDS, or EIPA. CONCLUSIONS MCT1, 2, and 4 are expressed in BCEC on both the apical and basolateral membrane (BL) surfaces consistent with niflumic acid-sensitive lactate-H(+) transport. Lactate dependent proton flux can activate Na(+)/H(+) exchange and be facilitated by maximizing intracellular buffering capacity through the presence of HCO(3)(-), HCO(3)(-) transport, NHE and CA activity.
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Affiliation(s)
- Tracy T Nguyen
- School of Optometry, Indiana University, Bloomington, Indiana 47405, USA
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Bonanno JA. Molecular mechanisms underlying the corneal endothelial pump. Exp Eye Res 2011; 95:2-7. [PMID: 21693119 DOI: 10.1016/j.exer.2011.06.004] [Citation(s) in RCA: 209] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2011] [Revised: 05/28/2011] [Accepted: 06/07/2011] [Indexed: 01/03/2023]
Abstract
The corneal endothelium is responsible for maintaining the hydration of the cornea. This is through a "Pump-Leak" mechanism where the active transport properties of the endothelium represent the "Pump" and the stromal swelling pressure represents the "Leak". For the "Pump", Na(+), K(+) ATPase activity and the presence of HCO(3)(-), Cl(-), and carbonic anhydrase activity are required. Several basolateral (stromal side) anion transporters, apical (facing the aqueous humor) ion channels and water channels have been identified that could support a model for ion secretion as the basis for the endothelial pump, however evidence of sustained anion fluxes, osmotic gradients or the need for water channels is lacking. This has prompted consideration of other models, such as Electro-osmosis, and consideration of metabolite flux as components of the endothelial pump. Although the conditions under which the "Pump" is supported are known, a complete model of the endothelial "Pump" has yet to emerge.
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Affiliation(s)
- Joseph A Bonanno
- Indiana University, School of Optometry, 800 E Atwater Avenue, Bloomington, IN 47405, USA.
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Fan T, Zhao J, Ma X, Xu X, Zhao W, Xu B. Establishment of a continuous untransfected human corneal endothelial cell line and its biocompatibility to denuded amniotic membrane. Mol Vis 2011; 17:469-80. [PMID: 21365020 PMCID: PMC3042360] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2010] [Accepted: 02/08/2011] [Indexed: 12/04/2022] Open
Abstract
PURPOSE To establish an untransfected human corneal endothelial (HCE) cell line and characterize its biocompatibility to denuded amniotic membrane (dAM). METHODS Primary culture was initiated with a pure population of HCE cells in DMEM/F12 media (pH 7.2) containing 20% fetal bovine serum and various supplements. The established cell line was characterized by growth property, chromosome analysis, morphology recovery, tumorigenicity assay, and expression of marker proteins, cell-junction proteins, and membrane transport proteins. The biocompatibility of HCE cells to dAM was evaluated by light microscopy, alizarin red staining, immunofluorescence assay, and electron microscopy. RESULTS HCE cells proliferated to confluence 6 weeks later in primary culture and have been subcultured to passage 224 so far. A continuous untransfected HCE cell line with a population doubling time of 26.20 h at passage 101 has been established. Results of chromosome analysis, morphology, combined with the results of expression of marker protein, cell-junction protein and membrane transport protein, suggested that the cells retained HCE cell properties and potencies to form cell junctions and perform membrane transport. Furthermore, HCE cells, without any tumorigenicity, could form confluent cell sheets on dAMs. The single layer sheets that attached tightly to dAMs had similar morphology and structure to those of HCE in situ and had an average cell density of 3,413±111 cells/mm². CONCLUSIONS An untransfected and non-tumorigenic HCE cell line has been established, and the cells maintained positive expression of marker proteins, cell-junction proteins and membrane transport proteins. The cell line, with excellent biocompatibility to dAM, might be used for in vitro reconstruction of HCE and provides a promising method for the treatment of diseases caused by corneal endothelial disorders.
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Xu Y, Krause A, Hamai H, Harvey BG, Worgall TS, Worgall S. Proinflammatory phenotype and increased caveolin-1 in alveolar macrophages with silenced CFTR mRNA. PLoS One 2010; 5:e11004. [PMID: 20543983 PMCID: PMC2882373 DOI: 10.1371/journal.pone.0011004] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2010] [Accepted: 05/15/2010] [Indexed: 11/18/2022] Open
Abstract
The inflammatory milieu in the respiratory tract in cystic fibrosis (CF) has been linked to the defective expression of the cystic transmembrane regulator (CFTR) in epithelial cells. Alveolar macrophages (AM), important contibutors to inflammatory responses in the lung, also express CFTR. The present study analyzes the phenotype of human AM with silenced CFTR. Expression of CFTR mRNA and the immature form of the CFTR protein decreased 100-fold and 5.2-fold, respectively, in AM transfected with a CFTR specific siRNA (CFTR-siRNA) compared to controls. Reduction of CFTR expression in AM resulted in increased secretion of IL-8, increased phosphorylation of NF-κB, a positive regulator of IL-8 expression, and decreased expression of IκB-α, the inhibitory protein of NF-κB activation. AM with silenced CFTR expression also showed increased apoptosis. We hypothesized that caveolin-1 (Cav1), a membrane protein that is co-localized with CFTR in lipid rafts and that is related to inflammation and apoptosis in macrophages, may be affected by decreased CFTR expression. Messenger RNA and protein levels of Cav1 were increased in AM with silenced CFTR. Expression and transcriptional activity of sterol regulatory element binding protein (SREBP), a negative transcriptional regulator of Cav1, was decreased in AM with silenced CFTR, but total and free cholesterol mass did not change. These findings indicate that silencing of CFTR in human AM results in an inflammatory phenotype and apoptosis, which is associated to SREBP-mediated regulation of Cav1.
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Affiliation(s)
- Yaqin Xu
- Department of Pediatrics, Weill Cornell Medical College, New York, New York, United States of America
| | - Anja Krause
- Department of Genetic Medicine, Weill Cornell Medical College, New York, New York, United States of America
| | - Hiroko Hamai
- Department of Pathology, Columbia University, New York, New York, United States of America
| | - Ben-Gary Harvey
- Department of Genetic Medicine, Weill Cornell Medical College, New York, New York, United States of America
| | - Tilla S. Worgall
- Department of Pathology, Columbia University, New York, New York, United States of America
| | - Stefan Worgall
- Department of Pediatrics, Weill Cornell Medical College, New York, New York, United States of America
- Department of Genetic Medicine, Weill Cornell Medical College, New York, New York, United States of America
- * E-mail:
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Cao L, Zhang XD, Liu X, Chen TY, Zhao M. Chloride channels and transporters in human corneal epithelium. Exp Eye Res 2010; 90:771-9. [PMID: 20346358 DOI: 10.1016/j.exer.2010.03.013] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2009] [Revised: 03/02/2010] [Accepted: 03/17/2010] [Indexed: 01/14/2023]
Abstract
Transport of water and electrolytes is critical for corneal clarity. Recent studies indicate another important function of transport of ions and electrolytes - establishing wound electric fields that guide cell migration. We found chloride (Cl(-)) flux is a major component of the corneal wound electric current. In order to elucidate the mechanisms of Cl(-) transport, we studied Cl(-) channels and transporters in human corneal epithelial (HCE) cells. We tested a transformed human corneal epithelial cell line (tHCE), primary cultures of human corneal epithelial cells (pHCE), and human donor corneas. We first used RT-PCR to determine expression levels of mRNA of CLC (Cl(-) channels/transporters of CLC gene family) family members and CFTR (cystic fibrosis transmembrane conductance regulator) in HCE cells. We then confirmed protein expression and distribution of selected CLC family members and CFTR with Western blot and immunofluorescence confocal microscopy. Finally, Cl(-) currents were recorded with electrophysiological techniques. The mRNAs of CLC-2, CLC-3, CLC-4, CLC-5, CLC-6, and CFTR were detected in the HCE cell line. CLC-1 and CLC-7 were not detectable. Western blot and immunostaining confirmed protein expression and distribution of CLC-2, CLC-3, CLC-4, CLC-6 and CFTR in human corneal epithelium. CLC-2 preferentially labeled the apical and basal layers, while CLC-3 and CLC-4 labeled only the superficial layer. CLC-6 and CFTR labeling showed a unique gradient with strong staining in apical layers which gradually decreased towards the basal layers. Corneal endothelium was positive for CLC-2, CLC-3, CLC-4, CLC-6 and possibly CFTR. Human corneal epithelial cells demonstrated voltage dependent Cl(-) currents. HCE cells express functional Cl(-) channels and transporters. CLC-2, CLC-3, CLC-4, CLC-6, and CFTR had distinct expression patterns in human corneal epithelium. Those molecules and their distribution may play important roles in maintaining resting Cl(-) fluxes and in regulating Cl(-) flux at corneal wounds, which may be a major contributor to wound electrical signaling.
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Affiliation(s)
- Lin Cao
- Department of Dermatology, University of California, Davis, CA 95618, USA
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Zheng W, Kuhlicke J, Jäckel K, Eltzschig HK, Singh A, Sjöblom M, Riederer B, Weinhold C, Seidler U, Colgan SP, Karhausen J. Hypoxia inducible factor-1 (HIF-1)-mediated repression of cystic fibrosis transmembrane conductance regulator (CFTR) in the intestinal epithelium. FASEB J 2008; 23:204-13. [PMID: 18779379 DOI: 10.1096/fj.08-110221] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Diarrhea is widespread in intestinal diseases involving ischemia and/or hypoxia. Since hypoxia alters stimulated Cl(-) and water flux, we investigated the influence of such a physiologically and pathophysiologically important signal on expression of the cystic fibrosis transmembrane conductance regulator (CFTR). Located on the apical membrane, this cAMP-activated Cl(-) channel determines salt and fluid transport across mucosal surfaces. Our studies revealed depression of CFTR mRNA, protein, and function in hypoxic epithelia. Chromatin immunoprecipitation identified a previously unappreciated binding site for the hypoxia inducible factor-1 (HIF-1), and promoter studies established its relevance by loss of repression following point mutation. Consequently, HIF-1 overexpressing cells exhibited significantly reduced transport capacity in colorimetric Cl(-) efflux studies, altered short circuit measurements, and changes in transepithelial fluid movement. Whole-body hypoxia in wild-type mice resulted in significantly reduced small intestinal fluid and HCO(3)(-) secretory responses to forskolin. Experiments performed in Cftr(-/-) and Nkcc1(-/-) mice underlined the role of altered CFTR expression for these functional changes, and work in conditional Hif1a mutant mice verified HIF-1-dependent CFTR regulation in vivo. In summary, our study clarifies CFTR regulation and introduces the concept of a HIF-1-orchestrated response designed to regulate ion and fluid movement across hypoxic intestinal epithelia.
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Affiliation(s)
- Wen Zheng
- Abteilung Gastroenterologie, Hepatologie und Endokrinologie, Medizinische Hochschule Hannover, Hannover,
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