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Angyal D, Bijvelds MJC, Bruno MJ, Peppelenbosch MP, de Jonge HR. Bicarbonate Transport in Cystic Fibrosis and Pancreatitis. Cells 2021; 11:cells11010054. [PMID: 35011616 PMCID: PMC8750324 DOI: 10.3390/cells11010054] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2021] [Revised: 12/20/2021] [Accepted: 12/21/2021] [Indexed: 12/12/2022] Open
Abstract
CFTR, the cystic fibrosis (CF) gene-encoded epithelial anion channel, has a prominent role in driving chloride, bicarbonate and fluid secretion in the ductal cells of the exocrine pancreas. Whereas severe mutations in CFTR cause fibrosis of the pancreas in utero, CFTR mutants with residual function, or CFTR variants with a normal chloride but defective bicarbonate permeability (CFTRBD), are associated with an enhanced risk of pancreatitis. Recent studies indicate that CFTR function is not only compromised in genetic but also in selected patients with an acquired form of pancreatitis induced by alcohol, bile salts or smoking. In this review, we summarize recent insights into the mechanism and regulation of CFTR-mediated and modulated bicarbonate secretion in the pancreatic duct, including the role of the osmotic stress/chloride sensor WNK1 and the scaffolding protein IRBIT, and current knowledge about the role of CFTR in genetic and acquired forms of pancreatitis. Furthermore, we discuss the perspectives for CFTR modulator therapy in the treatment of exocrine pancreatic insufficiency and pancreatitis and introduce pancreatic organoids as a promising model system to study CFTR function in the human pancreas, its role in the pathology of pancreatitis and its sensitivity to CFTR modulators on a personalized basis.
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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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Hegyi P, Maléth J, Walters JR, Hofmann AF, Keely SJ. Guts and Gall: Bile Acids in Regulation of Intestinal Epithelial Function in Health and Disease. Physiol Rev 2019; 98:1983-2023. [PMID: 30067158 DOI: 10.1152/physrev.00054.2017] [Citation(s) in RCA: 164] [Impact Index Per Article: 32.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Epithelial cells line the entire surface of the gastrointestinal tract and its accessory organs where they primarily function in transporting digestive enzymes, nutrients, electrolytes, and fluid to and from the luminal contents. At the same time, epithelial cells are responsible for forming a physical and biochemical barrier that prevents the entry into the body of harmful agents, such as bacteria and their toxins. Dysregulation of epithelial transport and barrier function is associated with the pathogenesis of a number of conditions throughout the intestine, such as inflammatory bowel disease, chronic diarrhea, pancreatitis, reflux esophagitis, and cancer. Driven by discovery of specific receptors on intestinal epithelial cells, new insights into mechanisms that control their synthesis and enterohepatic circulation, and a growing appreciation of their roles as bioactive bacterial metabolites, bile acids are currently receiving a great deal of interest as critical regulators of epithelial function in health and disease. This review aims to summarize recent advances in this field and to highlight how bile acids are now emerging as exciting new targets for disease intervention.
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Affiliation(s)
- Peter Hegyi
- Momentum Translational Gastroenterology Research Group, Hungarian Academy of Sciences-University of Szeged , Szeged , Hungary ; Institute for Translational Medicine, Medical School, University of Pécs , Pécs , Hungary ; Momentum Epithelial Cell Signalling and Secretion Research Group and First Department of Medicine, University of Szeged , Szeged , Hungary ; Division of Digestive Diseases, Department of Gastroenterology, Hammersmith Hospital, Imperial College London , London , United Kingdom ; Division of Gastroenterology, Department of Medicine, University of California, San Diego, La Jolla, California ; and Department of Molecular Medicine, Royal College of Surgeons in Ireland, Education and Research Centre, Beaumont Hospital , Dublin , Ireland
| | - Joszef Maléth
- Momentum Translational Gastroenterology Research Group, Hungarian Academy of Sciences-University of Szeged , Szeged , Hungary ; Institute for Translational Medicine, Medical School, University of Pécs , Pécs , Hungary ; Momentum Epithelial Cell Signalling and Secretion Research Group and First Department of Medicine, University of Szeged , Szeged , Hungary ; Division of Digestive Diseases, Department of Gastroenterology, Hammersmith Hospital, Imperial College London , London , United Kingdom ; Division of Gastroenterology, Department of Medicine, University of California, San Diego, La Jolla, California ; and Department of Molecular Medicine, Royal College of Surgeons in Ireland, Education and Research Centre, Beaumont Hospital , Dublin , Ireland
| | - Julian R Walters
- Momentum Translational Gastroenterology Research Group, Hungarian Academy of Sciences-University of Szeged , Szeged , Hungary ; Institute for Translational Medicine, Medical School, University of Pécs , Pécs , Hungary ; Momentum Epithelial Cell Signalling and Secretion Research Group and First Department of Medicine, University of Szeged , Szeged , Hungary ; Division of Digestive Diseases, Department of Gastroenterology, Hammersmith Hospital, Imperial College London , London , United Kingdom ; Division of Gastroenterology, Department of Medicine, University of California, San Diego, La Jolla, California ; and Department of Molecular Medicine, Royal College of Surgeons in Ireland, Education and Research Centre, Beaumont Hospital , Dublin , Ireland
| | - Alan F Hofmann
- Momentum Translational Gastroenterology Research Group, Hungarian Academy of Sciences-University of Szeged , Szeged , Hungary ; Institute for Translational Medicine, Medical School, University of Pécs , Pécs , Hungary ; Momentum Epithelial Cell Signalling and Secretion Research Group and First Department of Medicine, University of Szeged , Szeged , Hungary ; Division of Digestive Diseases, Department of Gastroenterology, Hammersmith Hospital, Imperial College London , London , United Kingdom ; Division of Gastroenterology, Department of Medicine, University of California, San Diego, La Jolla, California ; and Department of Molecular Medicine, Royal College of Surgeons in Ireland, Education and Research Centre, Beaumont Hospital , Dublin , Ireland
| | - Stephen J Keely
- Momentum Translational Gastroenterology Research Group, Hungarian Academy of Sciences-University of Szeged , Szeged , Hungary ; Institute for Translational Medicine, Medical School, University of Pécs , Pécs , Hungary ; Momentum Epithelial Cell Signalling and Secretion Research Group and First Department of Medicine, University of Szeged , Szeged , Hungary ; Division of Digestive Diseases, Department of Gastroenterology, Hammersmith Hospital, Imperial College London , London , United Kingdom ; Division of Gastroenterology, Department of Medicine, University of California, San Diego, La Jolla, California ; and Department of Molecular Medicine, Royal College of Surgeons in Ireland, Education and Research Centre, Beaumont Hospital , Dublin , Ireland
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Saint-Criq V, Gray MA. Role of CFTR in epithelial physiology. Cell Mol Life Sci 2016; 74:93-115. [PMID: 27714410 PMCID: PMC5209439 DOI: 10.1007/s00018-016-2391-y] [Citation(s) in RCA: 252] [Impact Index Per Article: 31.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Accepted: 09/28/2016] [Indexed: 12/20/2022]
Abstract
Salt and fluid absorption and secretion are two processes that are fundamental to epithelial function and whole body fluid homeostasis, and as such are tightly regulated in epithelial tissues. The CFTR anion channel plays a major role in regulating both secretion and absorption in a diverse range of epithelial tissues, including the airways, the GI and reproductive tracts, sweat and salivary glands. It is not surprising then that defects in CFTR function are linked to disease, including life-threatening secretory diarrhoeas, such as cholera, as well as the inherited disease, cystic fibrosis (CF), one of the most common life-limiting genetic diseases in Caucasian populations. More recently, CFTR dysfunction has also been implicated in the pathogenesis of acute pancreatitis, chronic obstructive pulmonary disease (COPD), and the hyper-responsiveness in asthma, underscoring its fundamental role in whole body health and disease. CFTR regulates many mechanisms in epithelial physiology, such as maintaining epithelial surface hydration and regulating luminal pH. Indeed, recent studies have identified luminal pH as an important arbiter of epithelial barrier function and innate defence, particularly in the airways and GI tract. In this chapter, we will illustrate the different operational roles of CFTR in epithelial function by describing its characteristics in three different tissues: the airways, the pancreas, and the sweat gland.
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Affiliation(s)
- Vinciane Saint-Criq
- Epithelial Research Group, Institute for Cell and Molecular Biosciences, University Medical School, Newcastle University, Framlington Place, Newcastle upon Tyne, NE2 4HH UK
| | - Michael A. Gray
- Epithelial Research Group, Institute for Cell and Molecular Biosciences, University Medical School, Newcastle University, Framlington Place, Newcastle upon Tyne, NE2 4HH UK
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Abstract
OBJECTIVES The aim of this study was to determine if comprehensive genetic testing was useful to identify genetic variants that discriminate chronic pancreatitis (CP) from acute recurrent pancreatitis (ARP) in a pediatric population. METHODS We conducted a retrospective review of 50 patients enrolled in our institutional pancreatitis registry between April 2013 and January 2015. Genetic analysis of PRSS1, CFTR, SPINK1, and CTRC classified variants as mutations or variants of unknown clinical significance and the minor allele frequency of variants in our cohort was obtained. RESULTS Genetic testing was obtained in 16/16 (100%) of CP and 29/34 (85%) of ARP patients. A total of 39 genetic variants were found in 27 (60%) of 45 subjects tested with 5 (11%) subjects having 2 different genes affected. Variant frequency was greatest in patients for CFTR (17/45, 38%) followed by SPINK1 (11/44, 25%), CTRC (2/27, 7%), and PRSS1 (2/44, 4%). CFTR variants were more likely in those with CP compared to ARP (63% and 24%, P = 0.01). CONCLUSIONS This study is the first to find a higher rate of CFTR mutations in CP versus ARP groups using comprehensive genetic testing in a pediatric population.
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Hegyi P, Wilschanski M, Muallem S, Lukacs GL, Sahin-Tóth M, Uc A, Gray MA, Rakonczay Z, Maléth J. CFTR: A New Horizon in the Pathomechanism and Treatment of Pancreatitis. Rev Physiol Biochem Pharmacol 2016; 170:37-66. [PMID: 26856995 DOI: 10.1007/112_2015_5002] [Citation(s) in RCA: 67] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Cystic fibrosis transmembrane conductance regulator (CFTR) is an ion channel that conducts chloride and bicarbonate ions across epithelial cell membranes. Mutations in the CFTR gene diminish the ion channel function and lead to impaired epithelial fluid transport in multiple organs such as the lung and the pancreas resulting in cystic fibrosis. Heterozygous carriers of CFTR mutations do not develop cystic fibrosis but exhibit increased risk for pancreatitis and associated pancreatic damage characterized by elevated mucus levels, fibrosis, and cyst formation. Importantly, recent studies demonstrated that pancreatitis causing insults, such as alcohol, smoking, or bile acids, strongly inhibit CFTR function. Furthermore, human studies showed reduced levels of CFTR expression and function in all forms of pancreatitis. These findings indicate that impairment of CFTR is critical in the development of pancreatitis; therefore, correcting CFTR function could be the first specific therapy in pancreatitis. In this review, we summarize recent advances in the field and discuss new possibilities for the treatment of pancreatitis.
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Affiliation(s)
- Péter Hegyi
- Institute for Translational Medicine and 1st Department of Medicine, University of Pécs, Pécs, Hungary.
- MTA-SZTE Translational Gastroenterology Research Group, Szeged, Hungary.
- First Department of Medicine, University of Szeged, Szeged, Hungary.
| | - Michael Wilschanski
- Pediatric Gastroenterology Unit, Hadassah Medical Center, Hebrew University, Jerusalem, Israel
| | - Shmuel Muallem
- National Institute of Dental and Craniofacial Research, Bethesda, MD, USA
| | | | - Miklós Sahin-Tóth
- Department of Molecular and Cell Biology, Boston University Henry M. Goldman School of Dental Medicine, Boston, MA, USA
| | - Aliye Uc
- Department of Pediatrics, University of Iowa, Carver College of Medicine, Iowa City, IA, USA
| | - Michael A Gray
- Institute for Cell & Molecular Biosciences, University Medical School, Newcastle University, Newcastle upon Tyne, UK
| | - Zoltán Rakonczay
- First Department of Medicine, University of Szeged, Szeged, Hungary
- Department of Pathophysiology, University of Szeged, Szeged, Hungary
| | - József Maléth
- First Department of Medicine, University of Szeged, Szeged, Hungary
- MTA-SZTE Translational Gastroenterology Research Group, Szeged, Hungary
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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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Abstract
The early phase of both acute and chronic pancreatitis can be characterized by disrupt level and function of the cystic fibrosis transmembrane conductance regulator (CFTR) Cl(-) channel, decreased bicarbonate secretion, intraductal acidosis, decrease of fluid secretion and elevation of mucoprotein levels. It is almost needless to say that these intrapancreatic changes are very similar to the pathophysiological changes observed in cystic fibrosis. The aim of this mini review is to describe the development of the above mentioned pathological observations in details, moreover highlight some future therapeutic opportunities in pancreatitis.
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Affiliation(s)
- Anita Balázs
- First Department of Medicine, University of Szeged, Szeged, Hungary
| | - Péter Hegyi
- First Department of Medicine, University of Szeged, Szeged, Hungary; MTA-SZTE Momentum Translational Gastroenterology Research Group, Szeged, Hungary.
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Hegyi P, Rakonczay Z. The role of pancreatic ducts in the pathogenesis of acute pancreatitis. Pancreatology 2015; 15:S13-7. [PMID: 25921231 DOI: 10.1016/j.pan.2015.03.010] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/13/2014] [Revised: 03/09/2015] [Accepted: 03/17/2015] [Indexed: 12/11/2022]
Abstract
Pancreatic ducts secrete 2.5 l of alkaline, HCO3(-)-rich fluid daily which greatly contributes to the homeostasis of the pancreas. Ducts are also important in the pathophysiology of the pancreas; alteration of ductal function can lead to severe diseases such as cystic fibrosis and chronic pancreatitis. The role of pancreatic ducts in the development of acute pancreatitis has only been uncovered recently. Pancreatitis inducing agents like bile acids and ethanol dose-dependently affect pancreatic ductal secretion; low concentrations stimulate, whereas high concentrations inhibit secretion. The majority of the review will focus on the central role of cystic fibrosis transmembrane conductance regulator (CFTR), a critical protein in the regulation of ductal secretion, in the pathogenesis of acute pancreatitis which is highlighted by numerous investigations. Downregulation of CFTR expression results in increased severity of acute pancreatitis in mice. Furthermore, human genetic studies have demonstrated statistically significant association of CFTR mutations with acute recurrent pancreatitis. Overall, the data support the involvement of pancreatic ducts in the pathogenesis of acute pancreatitis.
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Affiliation(s)
- Peter Hegyi
- University of Szeged, First Department of Medicine, Szeged, Hungary; MTA-SZTE Lendület Translational Gastroenterology Research Group, Szeged, Hungary
| | - Zoltan Rakonczay
- University of Szeged, First Department of Medicine, Szeged, Hungary.
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Kowal JM, Haanes KA, Christensen NM, Novak I. Bile acid effects are mediated by ATP release and purinergic signalling in exocrine pancreatic cells. Cell Commun Signal 2015; 13:28. [PMID: 26050734 PMCID: PMC4459444 DOI: 10.1186/s12964-015-0107-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2015] [Accepted: 05/26/2015] [Indexed: 02/06/2023] Open
Abstract
Background In many cells, bile acids (BAs) have a multitude of effects, some of which may be mediated by specific receptors such the TGR5 or FXR receptors. In pancreas systemic BAs, as well as intra-ductal BAs from bile reflux, can affect pancreatic secretion. Extracellular ATP and purinergic signalling are other important regulators of similar secretory mechanisms in pancreas. The aim of our study was to elucidate whether there is interplay between ATP and BA signalling. Results Here we show that CDCA (chenodeoxycholic acid) caused fast and concentration-dependent ATP release from acini (AR42J) and duct cells (Capan-1). Taurine and glycine conjugated forms of CDCA had smaller effects on ATP release in Capan-1 cells. In duct monolayers, CDCA stimulated ATP release mainly from the luminal membrane; the releasing mechanisms involved both vesicular and non-vesicular secretion pathways. Duct cells were not depleted of intracellular ATP with CDCA, but acinar cells lost some ATP, as detected by several methods including ATP sensor AT1.03YEMK. In duct cells, CDCA caused reversible increase in the intracellular Ca2+ concentration [Ca2 +]i, which could be significantly inhibited by antagonists of purinergic receptors. The TGR5 receptor, expressed on the luminal side of pancreatic ducts, was not involved in ATP release and Ca2+ signals, but could stimulate Na+/Ca2+ exchange in some conditions. Conclusions CDCA evokes significant ATP release that can stimulate purinergic receptors, which in turn increase [Ca2+]i. The TGR5 receptor is not involved in these processes but can play a protective role at high intracellular Ca2+ conditions. We propose that purinergic signalling could be taken into consideration in other cells/organs, and thereby potentially explain some of the multifaceted effects of BAs. Electronic supplementary material The online version of this article (doi:10.1186/s12964-015-0107-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Justyna M Kowal
- Department of Biology, Section for Cell Biology and Physiology, August Krogh Building, University of Copenhagen, Universitetsparken 13, DK-2100, Copenhagen, Denmark.
| | - Kristian A Haanes
- Department of Biology, Section for Cell Biology and Physiology, August Krogh Building, University of Copenhagen, Universitetsparken 13, DK-2100, Copenhagen, Denmark. .,Present address: Department of Clinical Experimental Research, Glostrup Research Institute, Copenhagen University Hospital, Glostrup, Denmark.
| | - Nynne M Christensen
- Department of Biology, Section for Cell Biology and Physiology, August Krogh Building, University of Copenhagen, Universitetsparken 13, DK-2100, Copenhagen, Denmark.
| | - Ivana Novak
- Department of Biology, Section for Cell Biology and Physiology, August Krogh Building, University of Copenhagen, Universitetsparken 13, DK-2100, Copenhagen, Denmark.
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Judák L, Hegyi P, Rakonczay Z, Maléth J, Gray MA, Venglovecz V. Ethanol and its non-oxidative metabolites profoundly inhibit CFTR function in pancreatic epithelial cells which is prevented by ATP supplementation. Pflugers Arch 2013; 466:549-62. [PMID: 23948742 DOI: 10.1007/s00424-013-1333-x] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2013] [Revised: 07/26/2013] [Accepted: 07/30/2013] [Indexed: 02/06/2023]
Abstract
Excessive alcohol consumption is a major cause of acute pancreatitis, but the mechanism involved is not well understood. Recent investigations suggest that pancreatic ductal epithelial cells (PDECs) help defend the pancreas from noxious agents such as alcohol. Because the cystic fibrosis transmembrane conductance regulator (CFTR) Cl(-) channel plays a major role in PDEC physiology and mutated CFTR is often associated with pancreatitis, we tested the hypothesis that ethanol affects CFTR to impair ductal function. Electrophysiological studies on native PDECs showed that ethanol (10 and 100 mM) increased basal, but reversibly blocked, forskolin-stimulated CFTR currents. The inhibitory effect of ethanol was mimicked by its non-oxidative metabolites, palmitoleic acid ethyl ester (POAEE) and palmitoleic acid (POA), but not by the oxidative metabolite, acetaldehyde. Ethanol, POAEE and POA markedly reduced intracellular ATP (ATPi) which was linked to CFTR inhibition since the inhibitory effects were almost completely abolished if ATPi depletion was prevented. We propose that ethanol causes functional damage of CFTR through an ATPi-dependent mechanism, which compromises ductal fluid secretion and likely contributes to the pathogenesis of acute pancreatitis. We suggest that the maintenance of ATPi may represent a therapeutic option in the treatment of the disease.
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Affiliation(s)
- L Judák
- Department of Pharmacology and Pharmacotherapy, University of Szeged, Szeged, Hungary
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12
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The Exocrine Pancreas: The Acinar-Ductal Tango in Physiology and Pathophysiology. Rev Physiol Biochem Pharmacol 2013; 165:1-30. [DOI: 10.1007/112_2013_14] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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13
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Xiao F, Li J, Singh AK, Riederer B, Wang J, Sultan A, Park H, Lee MG, Lamprecht G, Scholte BJ, De Jonge HR, Seidler U. Rescue of epithelial HCO3- secretion in murine intestine by apical membrane expression of the cystic fibrosis transmembrane conductance regulator mutant F508del. J Physiol 2012; 590:5317-34. [PMID: 22802588 DOI: 10.1113/jphysiol.2012.232124] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
This study investigated whether expression of the common cystic fibrosis transmembrane conductance regulator (CFTR) mutant F508del in the apical membrane of enterocytes confers increased bicarbonate secretory capacity on the intestinal epithelium of F508del mutant mice compared to that of CFTR knockout (KO) mice. CFTR KO mice, F508del mutant mice (F508del) and wild-type (WT) littermates were bred on the FVB/N background. F508del isolated brush border membrane (BBM) contained approximately 5-10% fully glycosylated band C protein compared to WT BBM. Similarly, the forskolin (FSK)-induced, CFTR-dependent short-circuit current (I(sc)) of F508del mucosa was approximately 5-10% of WT, whereas the HCO(3)(-) secretory response ( ) was almost half that of WT in both duodenum and mid-colon studied in vitro and in vivo. While WT intestine retained full FSK-induced in the absence of luminal Cl(-), the markedly higher than I(sc) in F508del intestine was dependent on the presence of luminal Cl(-), and was blocked by CFTR inhibitors. The Ste20-related proline-alanine-rich kinases (SPAK/OSR1), which are downstream of the with-no-lysine (K) protein kinases (WNK), were rapidly phosphorylated by FSK in WT and F508del, but significantly more slowly in CFTR KO intestine. In conclusion, the data demonstrate that low levels of F508del membrane expression in the intestine of F508del mice significantly increased FSK-induced HCO(3)(-) secretion mediated by Cl(-)/HCO(3)(-) exchange. However, in WT mucosa FSK elicited strong SPAK/OSR1 phosphorylation and Cl(-)-independent HCO(3)(-) efflux. This suggests that therapeutic strategies which deliver F508del to the apical membrane have the potential to significantly enhance epithelial HCO(3)(-) secretion.
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Affiliation(s)
- Fang Xiao
- Department of Gastoenterology, Hepatology and Endocrinology, Hannover Medical School, Hannover, Germany
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14
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Chávez JC, Hernández-González EO, Wertheimer E, Visconti PE, Darszon A, Treviño CL. Participation of the Cl-/HCO(3)- exchangers SLC26A3 and SLC26A6, the Cl- channel CFTR, and the regulatory factor SLC9A3R1 in mouse sperm capacitation. Biol Reprod 2012; 86:1-14. [PMID: 21976599 DOI: 10.1095/biolreprod.111.094037] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Sperm capacitation is required for fertilization and involves several ion permeability changes. Although Cl(-) and HCO(3)(-) are essential for capacitation, the molecular entities responsible for their transport are not fully known. During mouse sperm capacitation, the intracellular concentration of Cl(-) ([Cl(-)](i)) increases and membrane potential (Em) hyperpolarizes. As in noncapacitated sperm, the Cl(-) equilibrium potential appears to be close to the cell resting Em, opening of Cl(-) channels could not support the [Cl(-)](i) increase observed during capacitation. Alternatively, the [Cl(-)](i) increase might be mediated by anion exchangers. Among them, SLC26A3 and SLC26A6 are good candidates, since, in several cell types, they increase [Cl(-)](i) and interact with cystic fibrosis transmembrane conductance regulator (CFTR), a Cl(-) channel present in mouse and human sperm. This interaction is known to be mediated and probably regulated by the Na(+)/H(+) regulatory factor-1 (official symbol, SLC9A3R1). Our RT-PCR, immunocytochemistry, Western blot, and immunoprecipitation data indicate that SLC26A3, SLC26A6, and SLC9A3R1 are expressed in mouse sperm, localize to the midpiece, and interact between each other and with CFTR. Moreover, we present evidence indicating that CFTR and SLC26A3 are involved in the [Cl(-)](i) increase induced by db-cAMP in noncapacitated sperm. Furthermore, we found that inhibitors of SLC26A3 (Tenidap and 5099) interfere with the Em changes that accompany capacitation. Together, these findings indicate that a CFTR/SLC26A3 functional interaction is important for mouse sperm capacitation.
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Affiliation(s)
- Julio C Chávez
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología-Universidad Nacional Autónoma de México, Cuernavaca, México
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Ma K, He Y, Zhang H, Fei Q, Niu D, Wang D, Ding X, Xu H, Chen X, Zhu J. DNA methylation-regulated miR-193a-3p dictates resistance of hepatocellular carcinoma to 5-fluorouracil via repression of SRSF2 expression. J Biol Chem 2011; 287:5639-49. [PMID: 22117060 DOI: 10.1074/jbc.m111.291229] [Citation(s) in RCA: 92] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Chemoresistance prevents effective cancer therapy and is rarely predictable prior to treatment, particularly for hepatocellular carcinoma (HCC). Following the chemoresistance profiling of eight HCC cell lines to each of nine chemotherapeutics, two cell lines (QGY-7703 as a sensitive and SMMC-7721 as a resistant cell line to 5-fluorouracil (5-FU) treatment) were systematically studied for mechanistic insights underpinning HCC 5-FU chemoresistance. Genomic profiling at both DNA methylation and microRNA (miR) levels and subsequent mechanistic studies illustrate a new mechanism for how DNA methylation-regulated miR-193a-3p dictates the 5-FU resistance of HCC cells via repression of serine/arginine-rich splicing factor 2 (SRSF2) expression. In turn, SRSF2 preferentially up-regulates the proapoptotic splicing form of caspase 2 (CASP2L) and sensitizes HCC cells to 5-FU. Forced changes of miR-193a-3p level reverse all of the phenotypic features examined, including cell proliferation, cell cycle progression, and 5-FU sensitivity, in cell culture and in nude mice. Importantly, the siRNA-mediated repression of SRSF2 phenocopies all of the miR-193a-3p mimic-triggered changes in QGY-7703. This newly identified miR-193a-3p-SRSF2 axis highlights a new set of companion diagnostics required for optimal 5-FU therapy of HCC, which involve assaying both the DNA methylation state of the miR-193a gene and the expression of miR-193a-3p and SRSF2 and the relative level of the proapoptotic versus antiapoptotic splicing forms of caspase 2 in clinical samples.
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Affiliation(s)
- Kelong Ma
- Shanghai Medical College, Fudan University, Shanghai 200032, China
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Singh AK, Riederer B, Chen M, Xiao F, Krabbenhöft A, Engelhardt R, Nylander O, Soleimani M, Seidler U. The switch of intestinal Slc26 exchangers from anion absorptive to HCOFormula secretory mode is dependent on CFTR anion channel function. Am J Physiol Cell Physiol 2010; 298:C1057-65. [PMID: 20164375 DOI: 10.1152/ajpcell.00454.2009] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
CFTR has been recognized to function as both an anion channel and a key regulator of Slc26 anion transporters in heterologous expression systems. Whether this regulatory relationship between CFTR and Slc26 transporters is seen in native intestine, and whether this effect is coupled to CFTR transport function or other features of this protein, has not been studied. The duodena of anesthetized CFTR-, NHE3-, Slc26a6-, and Scl26a3-deficient mice and wild-type (WT) littermates were perfused, and duodenal bicarbonate (HCO(3)(-)) secretion (DBS) and fluid absorptive or secretory rates were measured. The selective NHE3 inhibitor S1611 or genetic ablation of NHE3 significantly reduced fluid absorptive rates and increased DBS. Slc26a6 (PAT1) or Slc26a3 (DRA) ablation reduced the S1611-induced DBS increase and reduced fluid absorptive rates, suggesting that the effect of S1611 or NHE3 ablation on HCO(3)(-) secretion may be an unmasking of Slc26a6- and Slc26a3-mediated Cl(-)/HCO(3)(-) exchange activity. In the absence of CFTR expression or after application of the CFTR(inh)-172, fluid absorptive rates were similar to those of WT, but S1611 induced virtually no increase in DBS, demonstrating that CFTR transport activity, and not just its presence, is required for Slc26-mediated duodenal HCO(3)(-) secretion. A functionally active CFTR is an absolute requirement for Slc26-mediated duodenal HCO(3)(-) secretion, but not for Slc26-mediated fluid absorption, in which these transporters operate in conjunction with the Na(+)/H(+) exchanger NHE3. This suggests that Slc26a6 and Slc26a3 need proton recycling via NHE3 to operate in the Cl(-) absorptive mode and Cl(-) exit via CFTR to operate in the HCO(3)(-) secretory mode.
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Affiliation(s)
- Anurag Kumar Singh
- Dept. of Gastroenterology, Hepatology and Endocrinology, Hannover Medical School, Germany
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