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Ébert A, Gál E, Tóth E, Szögi T, Hegyi P, Venglovecz V. Role of CFTR in diabetes-induced pancreatic ductal fluid and HCO 3 - secretion. J Physiol 2024; 602:1065-1083. [PMID: 38389307 DOI: 10.1113/jp285702] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Accepted: 01/17/2024] [Indexed: 02/24/2024] Open
Abstract
Type 1 diabetes is a disease of the endocrine pancreas; however, it also affects exocrine function. Although most studies have examined the effects of diabetes on acinar cells, much less is known regarding ductal cells, despite their important protective function in the pancreas. Therefore, we investigated the effect of diabetes on ductal function. Diabetes was induced in wild-type and cystic fibrosis transmembrane conductance regulator (CFTR) knockout mice following an i.p. administration of streptozotocin. Pancreatic ductal fluid and HCO3 - secretion were determined using fluid secretion measurements and fluorescence microscopy, respectively. The expression of ion transporters was measured by real-time PCR and immunohistochemistry. Transmission electron microscopy was used for the morphological characterization of the pancreas. Serum secretin and cholecystokinin levels were measured by an enzyme-linked immunosorbent assay. Ductal fluid and HCO3 - secretion, CFTR activity, and the expression of CFTR, Na+ /H+ exchanger-1, anoctamine-1 and aquaporin-1 were significantly elevated in diabetic mice. Acute or chronic glucose treatment did not affect HCO3 - secretion, but increased alkalizing transporter activity. Inhibition of CFTR significantly reduced HCO3 - secretion in both normal and diabetic mice. Serum levels of secretin and cholecystokinin were unchanged, but the expression of secretin receptors significantly increased in diabetic mice. Diabetes increases fluid and HCO3 - secretion in pancreatic ductal cells, which is associated with the increased function of ion and water transporters, particularly CFTR. KEY POINTS: There is a lively interaction between the exocrine and endocrine pancreas not only under physiological conditions, but also under pathophysiological conditions The most common disease affecting the endocrine part is type-1 diabetes mellitus (T1DM), which is often associated with pancreatic exocrine insufficiency Compared with acinar cells, there is considerably less information regarding the effect of diabetes on pancreatic ductal epithelial cells, despite the fact that the large amount of fluid and HCO3 - produced by ductal cells is essential for maintaining normal pancreatic functions Ductal fluid and HCO3 - secretion increase in T1DM, in which increased cystic fibrosis transmembrane conductance regulator activation plays a central role. We have identified a novel interaction between T1DM and ductal cells. Presumably, the increased ductal secretion represents a defence mechanism in the prevention of diabetes, but further studies are needed to clarify this issue.
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Affiliation(s)
- Attila Ébert
- Department of Pharmacology and Pharmacotherapy, University of Szeged, Szeged, Hungary
- ELI ALPS, ELI-HU Non-Proft Ltd, Szeged, Hungary
| | - Eleonóra Gál
- Department of Pharmacology and Pharmacotherapy, University of Szeged, Szeged, Hungary
| | - Emese Tóth
- Translational Pancreatology Research Group, Interdisciplinary Center of Excellence for Research Development and Innovation, University of Szeged, Szeged, Hungary
- Department of Health Sciences, Department of Theoretical and Integrative Health Sciences, University of Debrecen, Debrecen, Hungary
| | - Titanilla Szögi
- Department of Pathology, University of Szeged, Szeged, Hungary
| | - Péter Hegyi
- Translational Pancreatology Research Group, Interdisciplinary Center of Excellence for Research Development and Innovation, University of Szeged, Szeged, Hungary
- Institute for Translational Medicine, Szentágothai Research Centre, Medical School, University of Pécs, Pécs, Hungary
- Centre for Translational Medicine, Semmelweis University, Budapest, Hungary
- Division of Pancreatic Diseases, Heart and Vascular Center, Semmelweis University, Budapest, Hungary
| | - Viktória Venglovecz
- Department of Pharmacology and Pharmacotherapy, University of Szeged, Szeged, Hungary
- Institute for Translational Medicine, Szentágothai Research Centre, Medical School, University of Pécs, Pécs, Hungary
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2
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Heneghan JF, Majmundar AJ, Rivera A, Wohlgemuth JG, Dlott JS, Snyder LM, Hildebrandt F, Alper SL. Activation of 2-oxoglutarate receptor 1 (OXGR1) by α-ketoglutarate (αKG) does not detectably stimulate Pendrin-mediated anion exchange in Xenopus oocytes. Physiol Rep 2022; 10:e15362. [PMID: 35851763 PMCID: PMC9294391 DOI: 10.14814/phy2.15362] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2022] [Revised: 06/01/2022] [Accepted: 06/03/2022] [Indexed: 06/15/2023] Open
Abstract
SLC26A4/Pendrin is the major electroneutral Cl- /HCO3- exchanger of the apical membrane of the Type B intercalated cell (IC) of the connecting segment (CNT) and cortical collecting duct (CCD). Pendrin mediates both base secretion in response to systemic base load and Cl- reabsorption in response to systemic volume depletion, manifested as decreased nephron salt and water delivery to the distal nephron. Pendrin-mediated Cl- /HCO3- exchange in the apical membrane is upregulated through stimulation of the β-IC apical membrane G protein-coupled receptor, 2-oxoglutarate receptor 1 (OXGR1/GPR99), by its ligand α-ketoglutarate (αKG). αKG is both filtered by the glomerulus and lumenally secreted by proximal tubule apical membrane organic anion transporters (OATs). OXGR1-mediated regulation of Pendrin by αKG has been documented in transgenic mice and in isolated perfused CCD. However, aspects of the OXGR1 signaling pathway have remained little investigated since its original discovery in lymphocytes. Moreover, no ex vivo cellular system has been reported in which to study the OXGR1 signaling pathway of Type B-IC, a cell type refractory to survival in culture in its differentiated state. As Xenopus oocytes express robust heterologous Pendrin activity, we investigated OXGR1 regulation of Pendrin in oocytes. Despite functional expression of OXGR1 in oocytes, co-expression of Pendrin and OXGR1 failed to exhibit αKG-sensitive stimulation of Pendrin-mediated Cl- /anion exchange under a wide range of conditions. We conclude that Xenopus oocytes lack one or more essential molecular components or physical conditions required for OXGR1 to regulate Pendrin activity.
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Affiliation(s)
- John F. Heneghan
- Division of NephrologyBeth Israel Deaconess Medical CenterBostonMassachusettsUSA
- Department of MedicineHarvard Medical SchoolBostonMassachusettsUSA
| | - Amar J. Majmundar
- Division of NephrologyBoston Children's HospitalBostonMassachusettsUSA
- Department of PediatricsHarvard Medical SchoolBostonMassachusettsUSA
| | - Alicia Rivera
- Division of NephrologyBeth Israel Deaconess Medical CenterBostonMassachusettsUSA
- Department of MedicineHarvard Medical SchoolBostonMassachusettsUSA
| | | | | | | | - Friedhelm Hildebrandt
- Division of NephrologyBoston Children's HospitalBostonMassachusettsUSA
- Department of PediatricsHarvard Medical SchoolBostonMassachusettsUSA
- Department of GeneticsHarvard Medical SchoolBostonMassachusettsUSA
| | - Seth L. Alper
- Division of NephrologyBeth Israel Deaconess Medical CenterBostonMassachusettsUSA
- Department of MedicineHarvard Medical SchoolBostonMassachusettsUSA
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3
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Racz R, Nagy A, Rakonczay Z, Dunavari EK, Gerber G, Varga G. Defense Mechanisms Against Acid Exposure by Dental Enamel Formation, Saliva and Pancreatic Juice Production. Curr Pharm Des 2019; 24:2012-2022. [PMID: 29769002 PMCID: PMC6225347 DOI: 10.2174/1381612824666180515125654] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2018] [Revised: 04/30/2018] [Accepted: 05/08/2018] [Indexed: 12/16/2022]
Abstract
The pancreas, the salivary glands and the dental enamel producing ameloblasts have marked developmental, structural and functional similarities. One of the most striking similarities is their bicarbonate-rich secretory product, serving acid neutralization. An important difference between them is that while pancreatic juice and saliva are delivered into a lumen where they can be collected and analyzed, ameloblasts produce locally precipitating hydroxyapatite which cannot be easily studied. Interestingly, the ion and protein secretion by the pancreas, the salivary glands, and maturation ameloblasts are all two-step processes, of course with significant differences too. As they all have to defend against acid exposure by producing extremely large quantities of bicarbonate, the failure of this function leads to deteriorating consequences. The aim of the present review is to describe and characterize the defense mechanisms of the pancreas, the salivary glands and enamel-producing ameloblasts against acid exposure and to compare their functional capabilities to do this by producing bicarbonate.
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Affiliation(s)
- Robert Racz
- Department of Oral Biology, Semmelweis University, Budapest, Hungary
| | - Akos Nagy
- Department of Dentistry, Oral and Maxillofacial Surgery, University of Pecs, Pecs, Hungary
| | - Zoltan Rakonczay
- Department of Pathophysiology, University of Szeged, Szeged, Hungary
| | - Erika Katalin Dunavari
- Department of Dentistry, Oral and Maxillofacial Surgery, University of Pecs, Pecs, Hungary
| | - Gabor Gerber
- Department of Anatomy, Histology and Embryology, Semmelweis University, Budapest, Hungary
| | - Gabor Varga
- Department of Oral Biology, Semmelweis University, Budapest, Hungary
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4
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O'Malley Y, Rotti PG, Thornell IM, Vanegas Calderón OG, Febres-Aldana C, Durham K, Yao J, Li X, Zhu Z, Norris AW, Zabner J, Engelhardt JF, Uc A. Development of a polarized pancreatic ductular cell epithelium for physiological studies. J Appl Physiol (1985) 2018. [PMID: 29517421 DOI: 10.1152/japplphysiol.00043.2018] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Pancreatic ductular epithelial cells comprise the majority of duct cells in pancreas, control cystic fibrosis transmembrane conductance regulator (CFTR)-dependent bicarbonate ([Formula: see text]) secretion, but are difficult to grow as a polarized monolayer. Using NIH-3T3-J2 fibroblast feeder cells and a Rho-associated kinase inhibitor, we produced well-differentiated and polarized porcine pancreatic ductular epithelial cells. Cells grown on semipermeable filters at the air-liquid interface developed typical epithelial cell morphology and stable transepithelial resistance and expressed epithelial cell markers (zona occludens-1 and β-catenin), duct cell markers (SOX-9 and CFTR), but no acinar (amylase) or islet cell (chromogranin) markers. Polarized cells were studied in Ussing chambers bathed in Krebs-Ringer [Formula: see text] solution at 37°C gassed with 5% CO2 to measure short-circuit currents ( Isc). Ratiometric measurement of extracellular pH was performed with fluorescent SNARF-conjugated dextran at 5% CO2. Cells demonstrated a baseline Isc (12.2 ± 3.2 μA/cm2) that increased significantly in response to apical forskolin-IBMX (∆ Isc: 35.4 ± 3.8 μA/cm2, P < 0.001) or basolateral secretin (∆ Isc: 31.4 ± 2.5 μA/cm2, P < 0.001), both of which increase cellular levels of cAMP. Subsequent addition of apical GlyH-101, a CFTR inhibitor, decreased the current (∆ Isc: 20.4 ± 3.8 μA/cm2, P < 0.01). Extracellular pH and [Formula: see text] concentration increased significantly after forskolin-IBMX (pH: 7.18 ± 0.23 vs. 7.53 ± 0.19; [Formula: see text] concentration, 14.5 ± 5.9 vs. 31.8 ± 13.4 mM; P < 0.05 for both). We demonstrate the development of a polarized pancreatic ductular epithelial cell epithelium with CFTR-dependent [Formula: see text] secretion in response to secretin and cAMP. This model is highly relevant, as porcine pancreas physiology is very similar to humans and pancreatic damage in the cystic fibrosis pig model recapitulates that of humans. NEW & NOTEWORTHY Pancreas ductular epithelial cells control cystic fibrosis transmembrane conductance regulator (CFTR)-dependent bicarbonate secretion. Their function is critical because when CFTR is deficient in cystic fibrosis bicarbonate secretion is lost and the pancreas is damaged. Mechanisms that control pancreatic bicarbonate secretion are incompletely understood. We generated well-differentiated and polarized porcine pancreatic ductular epithelial cells and demonstrated feasibility of bicarbonate secretion. This novel method will advance our understanding of pancreas physiology and mechanisms of bicarbonate secretion.
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Affiliation(s)
- Yunxia O'Malley
- Stead Family Department of Pediatrics, University of Iowa , Iowa City, Iowa
| | - Pavana G Rotti
- Department of Anatomy and Cell Biology, University of Iowa , Iowa City, Iowa
| | - Ian M Thornell
- Department of Internal Medicine, University of Iowa , Iowa City, Iowa
| | | | - Christopher Febres-Aldana
- The Arkadi M. Rywlin M.D. Department of Pathology and Laboratory Medicine, Mount Sinai Medical Center , Miami Beach, Florida
| | - Katelin Durham
- Stead Family Department of Pediatrics, University of Iowa , Iowa City, Iowa
| | - Jianrong Yao
- Stead Family Department of Pediatrics, University of Iowa , Iowa City, Iowa
| | - Xiaopeng Li
- Department of Internal Medicine, University of Iowa , Iowa City, Iowa
| | - Zheng Zhu
- Stead Family Department of Pediatrics, University of Iowa , Iowa City, Iowa
| | - Andrew W Norris
- Stead Family Department of Pediatrics, University of Iowa , Iowa City, Iowa.,Fraternal Order of Eagles Diabetes Research Center, University of Iowa , Iowa City, Iowa
| | - Joseph Zabner
- Department of Internal Medicine, University of Iowa , Iowa City, Iowa
| | - John F Engelhardt
- Department of Anatomy and Cell Biology, University of Iowa , Iowa City, Iowa
| | - Aliye Uc
- Stead Family Department of Pediatrics, University of Iowa , Iowa City, Iowa
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5
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Pakai E, Tekus V, Zsiboras C, Rumbus Z, Olah E, Keringer P, Khidhir N, Matics R, Deres L, Ordog K, Szentes N, Pohoczky K, Kemeny A, Hegyi P, Pinter E, Garami A. The Neurokinin-1 Receptor Contributes to the Early Phase of Lipopolysaccharide-Induced Fever via Stimulation of Peripheral Cyclooxygenase-2 Protein Expression in Mice. Front Immunol 2018; 9:166. [PMID: 29459872 PMCID: PMC5807668 DOI: 10.3389/fimmu.2018.00166] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2017] [Accepted: 01/18/2018] [Indexed: 12/20/2022] Open
Abstract
Neurokinin (NK) signaling is involved in various inflammatory processes. A common manifestation of systemic inflammation is fever, which is usually induced in animal models with the administration of bacterial lipopolysaccharide (LPS). A role for the NK1 receptor was shown in LPS-induced fever, but the underlying mechanisms of how the NK1 receptor contributes to febrile response, especially in the early phase, have remained unknown. We administered LPS (120 µg/kg, intraperitoneally) to mice with the Tacr1 gene, i.e., the gene encoding the NK1 receptor, either present (Tacr1+/+ ) or absent (Tacr1-/- ) and measured their thermoregulatory responses, serum cytokine levels, tissue cyclooxygenase-2 (COX-2) expression, and prostaglandin (PG) E2 concentration. We found that the LPS-induced febrile response was attenuated in Tacr1-/- compared to their Tacr1+/+ littermates starting from 40 min postinfusion. The febrigenic effect of intracerebroventricularly administered PGE2 was not suppressed in the Tacr1-/- mice. Serum concentration of pyrogenic cytokines did not differ between Tacr1-/- and Tacr1+/+ at 40 min post-LPS infusion. Administration of LPS resulted in amplification of COX-2 mRNA expression in the lungs, liver, and brain of the mice, which was statistically indistinguishable between the genotypes. In contrast, the LPS-induced augmentation of COX-2 protein expression was attenuated in the lungs and tended to be suppressed in the liver of Tacr1-/- mice compared with Tacr1+/+ mice. The Tacr1+/+ mice responded to LPS with a significant surge of PGE2 production in the lungs, whereas Tacr1-/- mice did not. In conclusion, the NK1 receptor is necessary for normal fever genesis. Our results suggest that the NK1 receptor contributes to the early phase of LPS-induced fever by enhancing COX-2 protein expression in the periphery. These findings advance the understanding of the crosstalk between NK signaling and the "cytokine-COX-2-prostaglandin E2" axis in systemic inflammation, thereby open up the possibilities for new therapeutic approaches.
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Affiliation(s)
- Eszter Pakai
- Institute for Translational Medicine, Medical School, University of Pecs, Pecs, Hungary.,Momentum Gastroenterology Multidisciplinary Research Group, Hungarian Academy of Sciences - University of Szeged, Szeged, Hungary
| | - Valeria Tekus
- Department of Pharmacology and Pharmacotherapy, Medical School, University of Pecs, Pecs, Hungary.,Janos Szentagothai Research Centre, University of Pecs, Pecs, Hungary
| | - Csaba Zsiboras
- Institute for Translational Medicine, Medical School, University of Pecs, Pecs, Hungary
| | - Zoltan Rumbus
- Institute for Translational Medicine, Medical School, University of Pecs, Pecs, Hungary
| | - Emoke Olah
- Institute for Translational Medicine, Medical School, University of Pecs, Pecs, Hungary
| | - Patrik Keringer
- Institute for Translational Medicine, Medical School, University of Pecs, Pecs, Hungary
| | - Nora Khidhir
- Institute for Translational Medicine, Medical School, University of Pecs, Pecs, Hungary
| | - Robert Matics
- Institute for Translational Medicine, Medical School, University of Pecs, Pecs, Hungary
| | - Laszlo Deres
- Janos Szentagothai Research Centre, University of Pecs, Pecs, Hungary.,First Department of Medicine, Medical School, University of Pecs, Pecs, Hungary
| | - Katalin Ordog
- Janos Szentagothai Research Centre, University of Pecs, Pecs, Hungary.,First Department of Medicine, Medical School, University of Pecs, Pecs, Hungary
| | - Nikolett Szentes
- Department of Pharmacology and Pharmacotherapy, Medical School, University of Pecs, Pecs, Hungary.,Janos Szentagothai Research Centre, University of Pecs, Pecs, Hungary
| | - Krisztina Pohoczky
- Department of Pharmacology and Pharmacotherapy, Medical School, University of Pecs, Pecs, Hungary.,Janos Szentagothai Research Centre, University of Pecs, Pecs, Hungary
| | - Agnes Kemeny
- Janos Szentagothai Research Centre, University of Pecs, Pecs, Hungary.,Department of Medical Biology, Medical School, University of Pecs, Pecs, Hungary
| | - Peter Hegyi
- Institute for Translational Medicine, Medical School, University of Pecs, Pecs, Hungary.,Momentum Gastroenterology Multidisciplinary Research Group, Hungarian Academy of Sciences - University of Szeged, Szeged, Hungary.,First Department of Medicine, University of Szeged, Szeged, Hungary
| | - Erika Pinter
- Department of Pharmacology and Pharmacotherapy, Medical School, University of Pecs, Pecs, Hungary.,Janos Szentagothai Research Centre, University of Pecs, Pecs, Hungary
| | - Andras Garami
- Institute for Translational Medicine, Medical School, University of Pecs, Pecs, Hungary
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6
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Fleming AK, Storz P. Protein kinase C isoforms in the normal pancreas and in pancreatic disease. Cell Signal 2017; 40:1-9. [PMID: 28826907 DOI: 10.1016/j.cellsig.2017.08.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2017] [Accepted: 08/17/2017] [Indexed: 12/16/2022]
Abstract
Protein Kinase C isoforms have been implicated in regulating multiple processes within the healthy pancreas. Moreover, their dysregulation contributes to all aspects of pancreatic disease. In this review, with a focus on acinar, ductal, and islet cells, we highlight the roles and contributions of the different PKC isoforms to normal pancreas function. We also discuss the contribution of PKC enzymes to pancreatic diseases, including insulin resistance and diabetes mellitus, as well as pancreatitis and the development and progression of pancreatic cancer.
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Affiliation(s)
- Alicia K Fleming
- Department of Cancer Biology, Mayo Clinic, Jacksonville, FL, USA
| | - Peter Storz
- Department of Cancer Biology, Mayo Clinic, Jacksonville, FL, USA.
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7
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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: 241] [Impact Index Per Article: 30.1] [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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8
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Katona M, Hegyi P, Kui B, Balla Z, Rakonczay Z, Rázga Z, Tiszlavicz L, Maléth J, Venglovecz V. A novel, protective role of ursodeoxycholate in bile-induced pancreatic ductal injury. Am J Physiol Gastrointest Liver Physiol 2016; 310:G193-204. [PMID: 26608189 DOI: 10.1152/ajpgi.00317.2015] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/10/2015] [Accepted: 11/23/2015] [Indexed: 01/31/2023]
Abstract
We have previously shown that chenodeoxycholic acid (CDCA) strongly inhibits pancreatic ductal HCO3 (-) secretion through the destruction of mitochondrial function, which may have significance in the pathomechanism of acute pancreatitis (AP). Ursodeoxycholic acid (UDCA) is known to protect the mitochondria against hydrophobic bile acids and has an ameliorating effect on cell death. Therefore, our aim was to investigate the effect of UDCA pretreatment on CDCA-induced pancreatic ductal injury. Guinea pig intrainterlobular pancreatic ducts were isolated by collagenase digestion. Ducts were treated with UDCA for 5 and 24 h, and the effect of CDCA on intracellular Ca(2+) concentration ([Ca(2+)]i), intracellular pH (pHi), morphological and functional changes of mitochondria, and the rate of apoptosis were investigated. AP was induced in rat by retrograde intraductal injection of CDCA (0.5%), and the disease severity of pancreatitis was assessed by measuring standard laboratory and histological parameters. Twenty-four-hour pretreatment of pancreatic ducts with 0.5 mM UDCA significantly reduced the rate of ATP depletion, mitochondrial injury, and cell death induced by 1 mM CDCA and completely prevented the inhibitory effect of CDCA on acid-base transporters. UDCA pretreatment had no effect on CDCA-induced Ca(2+) signaling. Oral administration of UDCA (250 mg/kg) markedly reduced the severity of CDCA-induced AP. Our results clearly demonstrate that UDCA 1) suppresses the CDCA-induced pancreatic ductal injury by reducing apoptosis and mitochondrial damage and 2) reduces the severity of CDCA-induced AP. The protective effect of UDCA against hydrophobic bile acids may represent a novel therapeutic target in the treatment of biliary AP.
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Affiliation(s)
- Máté Katona
- Department of Pharmacology and Pharmacotherapy, University of Szeged, Szeged, Hungary
| | - Péter Hegyi
- Institute for Translational Medicine and First Department of Medicine, University of Pécs, Pécs, Hungary; First Department of Medicine, University of Szeged, Szeged, Hungary; MTA-SZTE Translational Gastroenterology Research Group, University of Szeged, Szeged, Hungary
| | - Balázs Kui
- First Department of Medicine, University of Szeged, Szeged, Hungary
| | - Zsolt Balla
- Department of Pathophysiology, University of Szeged, Szeged, Hungary; and Department of Pathophysiology, University of Szeged, Szeged, Hungary; and
| | - Zoltán Rakonczay
- First Department of Medicine, University of Szeged, Szeged, Hungary; Department of Pathophysiology, University of Szeged, Szeged, Hungary; and
| | - Zsolt Rázga
- Department of Pathology, University of Szeged, Szeged, Hungary
| | | | - József Maléth
- First Department of Medicine, University of Szeged, Szeged, Hungary
| | - Viktória Venglovecz
- Department of Pharmacology and Pharmacotherapy, University of Szeged, Szeged, Hungary;
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9
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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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10
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The role of pancreatic ductal secretion in protection against acute pancreatitis in mice*. Crit Care Med 2014; 42:e177-88. [PMID: 24368347 DOI: 10.1097/ccm.0000000000000101] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
OBJECTIVES A common potentially fatal disease of the pancreas is acute pancreatitis, for which there is no treatment. Most studies of this disorder focus on the damage to acinar cells since they are assumed to be the primary target of multiple stressors affecting the pancreas. However, increasing evidence suggests that the ducts may also have a crucial role in induction of the disease. To test this hypothesis, we sought to determine the specific role of the duct in the induction of acute pancreatitis using well-established disease models and mice with deletion of the Na/H exchanger regulatory factor-1 that have selectively impaired ductal function. DESIGN Randomized animal study. SETTING Animal research laboratory. SUBJECTS Wild-type and Na/H exchanger regulatory factor-1 knockout mice. INTERVENTIONS Acute necrotizing pancreatitis was induced by i.p. administration of cerulein or by intraductal administration of sodium taurocholate. The pancreatic expression of Na/H exchanger regulatory factor-1 and cystic fibrosis transmembrane conductance regulator (a key player in the control of ductal secretion) was analyzed by immunohistochemistry. In vivo pancreatic ductal secretion was studied in anesthetized mice. Functions of pancreatic acinar and ductal cells as well as inflammatory cells were analyzed in vitro. MEASUREMENTS AND MAIN RESULTS Deletion of Na/H exchanger regulatory factor-1 resulted in gross mislocalization of cystic fibrosis transmembrane conductance regulator, causing marked reduction in pancreatic ductal fluid and bicarbonate secretion. Importantly, deletion of Na/H exchanger regulatory factor-1 had no deleterious effect on functions of acinar and inflammatory cells. Deletion of Na/H exchanger regulatory factor-1, which specifically impaired ductal function, increased the severity of acute pancreatitis in the two mouse models tested. CONCLUSIONS Our findings provide the first direct evidence for the crucial role of ductal secretion in protecting the pancreas from acute pancreatitis and strongly suggest that improved ductal function should be an important modality in prevention and treatment of the disease.
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11
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May O, Yu H, Riederer B, Manns MP, Seidler U, Bachmann O. Short-term regulation of murine colonic NBCe1-B (electrogenic Na+/HCO3(-) cotransporter) membrane expression and activity by protein kinase C. PLoS One 2014; 9:e92275. [PMID: 24642792 PMCID: PMC3958514 DOI: 10.1371/journal.pone.0092275] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2013] [Accepted: 02/20/2014] [Indexed: 12/22/2022] Open
Abstract
The colonic mucosa actively secretes HCO3(-), and several lines of evidence point to an important role of Na+/HCO3(-) cotransport (NBC) as a basolateral HCO3(-) import pathway. We could recently demonstrate that the predominant NBC isoform in murine colonic crypts is electrogenic NBCe1-B, and that secretagogues cause NBCe1 exocytosis, which likely represents a component of NBC activation. Since protein kinase C (PKC) plays a key role in the regulation of ion transport by trafficking events, we asked whether it is also involved in the observed NBC activity increase. Crypts were isolated from murine proximal colon to assess PKC activation as well as NBC function and membrane abundance using fluorometric pHi measurements and cell surface biotinylation, respectively. PKC isoform translocation and phosphorylation occurred in response to PMA-, as well as secretagogue stimulation. The conventional and novel PKC inhibitors Gö6976 or Gö6850 did not alter NBC function or surface expression by themselves, but stimulation with forskolin (10(-5) M) or carbachol (10(-4) M) in their presence led to a significant decrease in NBC-mediated proton flux, and biotinylated NBCe1. Our data thus indicate that secretagogues lead to PKC translocation and phosphorylation in murine colonic crypts, and that PKC is necessary for the increase in NBC transport rate and membrane abundance caused by cholinergic and cAMP-dependent stimuli.
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Affiliation(s)
- Oliver May
- Department of Gastroenterology, Hepatology and Endocrinology, Hannover Medical School, Hannover, Germany
| | - Haoyang Yu
- Department of Gastroenterology, Hepatology and Endocrinology, Hannover Medical School, Hannover, Germany
| | - Brigitte Riederer
- Department of Gastroenterology, Hepatology and Endocrinology, Hannover Medical School, Hannover, Germany
| | - Michael P. Manns
- Department of Gastroenterology, Hepatology and Endocrinology, Hannover Medical School, Hannover, Germany
| | - Ursula Seidler
- Department of Gastroenterology, Hepatology and Endocrinology, Hannover Medical School, Hannover, Germany
| | - Oliver Bachmann
- Department of Gastroenterology, Hepatology and Endocrinology, Hannover Medical School, Hannover, Germany
- * E-mail:
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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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Pallagi P, Venglovecz V, Rakonczay Z, Borka K, Korompay A, Ózsvári B, Judák L, Sahin-Tóth M, Geisz A, Schnúr A, Maléth J, Takács T, Gray MA, Argent BE, Mayerle J, Lerch MM, Wittmann T, Hegyi P. Trypsin reduces pancreatic ductal bicarbonate secretion by inhibiting CFTR Cl⁻ channels and luminal anion exchangers. Gastroenterology 2011; 141:2228-2239.e6. [PMID: 21893120 PMCID: PMC3273991 DOI: 10.1053/j.gastro.2011.08.039] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/26/2010] [Revised: 07/14/2011] [Accepted: 08/05/2011] [Indexed: 12/16/2022]
Abstract
BACKGROUND & AIMS The effects of trypsin on pancreatic ductal epithelial cells (PDECs) vary among species and depend on the localization of proteinase-activated receptor 2 (PAR-2). We compared PAR-2 localization in human and guinea-pig PDECs, and used isolated guinea pig ducts to study the effects of trypsin and a PAR-2 agonist on bicarbonate secretion. METHODS PAR-2 localization was analyzed by immunohistochemistry in guinea pig and human pancreatic tissue samples (from 15 patients with chronic pancreatitis and 15 without pancreatic disease). Functionally, guinea pig PDECs were studied by microperfusion of isolated ducts, measurements of intracellular pH and intracellular Ca(2+) concentration, and patch clamp analysis. The effect of pH on trypsinogen autoactivation was assessed using recombinant human cationic trypsinogen. RESULTS PAR-2 localized to the apical membrane of human and guinea pig PDECs. Trypsin increased intracellular Ca(2+) concentration and intracellular pH and inhibited secretion of bicarbonate by the luminal anion exchanger and the cystic fibrosis transmembrane conductance regulator (CFTR) Cl(-) channel. Autoactivation of human cationic trypsinogen accelerated when the pH was reduced from 8.5 to 6.0. PAR-2 expression was strongly down-regulated, at transcriptional and protein levels, in the ducts of patients with chronic pancreatitis, consistent with increased activity of intraductal trypsin. Importantly, in PAR-2 knockout mice, the effects of trypsin were markedly reduced. CONCLUSIONS Trypsin reduces pancreatic ductal bicarbonate secretion via PAR-2-dependent inhibition of the apical anion exchanger and the CFTR Cl(-) channel. This could contribute to the development of chronic pancreatitis by decreasing luminal pH and promoting premature activation of trypsinogen in the pancreatic ducts.
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Affiliation(s)
- Petra Pallagi
- First Dept. of Medicine, University of Szeged, Szeged, Hungary
| | | | | | - Katalin Borka
- 2nd Dept. of Pathology, Semmelweis University, Budapest, Hungary
| | - Anna Korompay
- 2nd Dept. of Pathology, Semmelweis University, Budapest, Hungary
| | - Béla Ózsvári
- First Dept. of Medicine, University of Szeged, Szeged, Hungary
| | - Linda Judák
- First Dept. of Medicine, University of Szeged, Szeged, Hungary
| | - Miklós Sahin-Tóth
- Dept. of Molecular and Cell Biology, Henry M. Goldman School of Dental Medicine, Boston University, Boston, MA, USA
| | - Andrea Geisz
- First Dept. of Medicine, University of Szeged, Szeged, Hungary,Dept. of Molecular and Cell Biology, Henry M. Goldman School of Dental Medicine, Boston University, Boston, MA, USA
| | - Andrea Schnúr
- First Dept. of Medicine, University of Szeged, Szeged, Hungary,Dept. of Molecular and Cell Biology, Henry M. Goldman School of Dental Medicine, Boston University, Boston, MA, USA
| | - József Maléth
- First Dept. of Medicine, University of Szeged, Szeged, Hungary
| | - Tamás Takács
- First Dept. of Medicine, University of Szeged, Szeged, Hungary
| | - Mike A. Gray
- Institute for Cell & Molecular Biosciences, Newcastle University, Newcastle upon Tyne, UK
| | - Barry E. Argent
- Institute for Cell & Molecular Biosciences, Newcastle University, Newcastle upon Tyne, UK
| | - Julia Mayerle
- Department of Medicine A, Greifswald University Hospital, Greifswald, Germany
| | - Markus M. Lerch
- Department of Medicine A, Greifswald University Hospital, Greifswald, Germany
| | - Tibor Wittmann
- First Dept. of Medicine, University of Szeged, Szeged, Hungary
| | - Péter Hegyi
- First Dept. of Medicine, University of Szeged, Szeged, Hungary
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Sancho V, Berna MJ, Thill M, Jensen RT. PKCθ activation in pancreatic acinar cells by gastrointestinal hormones/neurotransmitters and growth factors is needed for stimulation of numerous important cellular signaling cascades. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2011; 1813:2145-56. [PMID: 21810446 DOI: 10.1016/j.bbamcr.2011.07.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2011] [Revised: 07/12/2011] [Accepted: 07/13/2011] [Indexed: 02/08/2023]
Abstract
The novel PKCθ isoform is highly expressed in T-cells, brain and skeletal muscle and originally thought to have a restricted distribution. It has been extensively studied in T-cells and shown to be important for apoptosis, T-cell activation and proliferation. Recent studies showed its presence in other tissues and importance in insulin signaling, lung surfactant secretion, intestinal barrier permeability, platelet and mast-cell functions. However, little information is available for PKCθ activation by gastrointestinal (GI) hormones/neurotransmitters and growth factors. In the present study we used rat pancreatic acinar cells to explore their ability to activate PKCθ and the possible interactions with important cellular mediators of their actions. Particular attention was paid to cholecystokinin (CCK), a physiological regulator of pancreatic function and important in pathological processes affecting acinar function, like pancreatitis. PKCθ-protein/mRNA was present in the pancreatic acini, and T538-PKCθ phosphorylation/activation was stimulated only by hormones/neurotransmitters activating phospholipase C. PKCθ was activated in time- and dose-related manner by CCK, mediated 30% by high-affinity CCK(A)-receptor activation. CCK stimulated PKCθ translocation from cytosol to membrane. PKCθ inhibition (by pseudostrate-inhibitor or dominant negative) inhibited CCK- and TPA-stimulation of PKD, Src, RafC, PYK2, p125(FAK) and IKKα/β, but not basal/stimulated enzyme secretion. Also CCK- and TPA-induced PKCθ activation produced an increment in PKCθ's direct association with AKT, RafA, RafC and Lyn. These results show for the first time the PKCθ presence in pancreatic acinar cells, its activation by some GI hormones/neurotransmitters and involvement in important cell signaling pathways mediating physiological responses (enzyme secretion, proliferation, apoptosis, cytokine expression, and pathological responses like pancreatitis and cancer growth).
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Affiliation(s)
- Veronica Sancho
- Digestive Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-1804, USA
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Treharne KJ, Xu Z, Chen JH, Best OG, Cassidy DM, Gruenert DC, Hegyi P, Gray MA, Sheppard DN, Kunzelmann K, Mehta A. Inhibition of protein kinase CK2 closes the CFTR Cl channel, but has no effect on the cystic fibrosis mutant deltaF508-CFTR. Cell Physiol Biochem 2009; 24:347-60. [PMID: 19910675 DOI: 10.1159/000257427] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/24/2009] [Indexed: 01/10/2023] Open
Abstract
BACKGROUND Deletion of phenylalanine-508 (DeltaF508) from the first nucleotide-binding domain (NBD1) in the wild-type cystic fibrosis (CF) transmembrane-conductance regulator (wtCFTR) causes CF. However, the mechanistic relationship between DeltaF508-CFTR and the diversity of CF disease is unexplained. The surface location of F508 on NBD1 creates the potential for protein-protein interactions and nearby, lies a consensus sequence (SYDE) reported to control the pleiotropic protein kinase CK2. METHODS Electrophysiology, immunofluorescence and biochemistry applied to CFTR-expressing cells, Xenopus oocytes, pancreatic ducts and patient biopsies. RESULTS Irrespective of PKA activation, CK2 inhibition (ducts, oocytes, cells) attenuates CFTR-dependent Cl(-) transport, closing wtCFTR in cell-attached membrane patches. CK2 and wtCFTR co-precipitate and CK2 co-localized with wtCFTR (but not DeltaF508-CFTR) in apical membranes of human airway biopsies. Comparing wild-type and DeltaF508CFTR expressing oocytes, only DeltaF508-CFTR Cl(-) currents were insensitive to two CK2 inhibitors. Furthermore, wtCFTR was inhibited by injecting a peptide mimicking the F508 region, whereas the DeltaF508-equivalent peptide had no effect. CONCLUSIONS CK2 controls wtCFTR, but not DeltaF508-CFTR. Others find that peptides from the F508 region of NBD1 allosterically control CK2, acting through F508. Hence, disruption of CK2-CFTR interaction by DeltaF508-CFTR might disrupt multiple, membrane-associated, CK2-dependent pathways, creating a new molecular disease paradigm for deleted F508 in CFTR.
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Affiliation(s)
- Kate J Treharne
- Centre for Cardiovascular and Lung Biology, University of Dundee, Ninewells Hospital, UK
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Abstract
PURPOSE OF REVIEW The pancreatic duct epithelium is remarkable for its capacity to secrete HCO(3)(-) ions at concentrations as high as 140 mmol/l. The properties of the key transporters involved in this process and the central role played by cystic fibrosis transmembrane conductance regulator (CFTR) are the main focus of this review. RECENT FINDINGS The Cl(-)/HCO(3)(-) exchanger at the apical membrane of pancreatic duct cells is now known to be SLC26A6. The 1: 2 stoichiometry and electrogenicity of this exchanger enable it to contribute to the secretion of HCO(3)(-) at high concentrations. The apical CFTR channels also appear to have sufficient HCO(3)(-) permeability to contribute directly to HCO(3)(-) secretion. There is a strong possibility that the Ca(2+)-activated Cl(-) channels at the apical membrane are members of the bestrophin family which, like CFTR, are also permeable to HCO(3)(-). More has been learned about the complex interactions between CFTR and other transporters within macromolecular complexes coordinated at the apical membrane by scaffolding proteins. Further details are also emerging of the protective paracrine roles of nucleotides, nucleosides, bile acids and trypsin in the regulation of ductal secretion. SUMMARY Most of the key transporters involved in Cl(-) and HCO(3)(-) secretion have now been identified and characterized. Current research focuses on the molecular interactions between these transporters and the ways in which they are regulated by extracellular signals.
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Stewart AK, Yamamoto A, Nakakuki M, Kondo T, Alper SL, Ishiguro H. Functional coupling of apical Cl-/HCO3- exchange with CFTR in stimulated HCO3- secretion by guinea pig interlobular pancreatic duct. Am J Physiol Gastrointest Liver Physiol 2009; 296:G1307-17. [PMID: 19342507 PMCID: PMC2697944 DOI: 10.1152/ajpgi.90697.2008] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Pancreatic ductal epithelium produces a HCO(3)(-)-rich fluid. HCO(3)(-) transport across ductal apical membranes has been proposed to be mediated by both SLC26-mediated Cl(-)/HCO(3)(-) exchange and CFTR-mediated HCO(3)(-) conductance, with proportional contributions determined in part by axial changes in gene expression and luminal anion composition. In this study we investigated the characteristics of apical Cl(-)/HCO(3)(-) exchange and its functional interaction with Cftr activity in isolated interlobular ducts of guinea pig pancreas. BCECF-loaded epithelial cells of luminally microperfused ducts were alkalinized by acetate prepulse or by luminal Cl(-) removal in the presence of HCO(3)(-)-CO(2). Intracellular pH recovery upon luminal Cl(-) restoration (nominal Cl(-)/HCO(3)(-) exchange) in cAMP-stimulated ducts was largely inhibited by luminal dihydro-DIDS (H(2)DIDS), accelerated by luminal CFTR inhibitor inh-172 (CFTRinh-172), and was insensitive to elevated bath K(+) concentration. Luminal introduction of CFTRinh-172 into sealed duct lumens containing BCECF-dextran in HCO(3)(-)-free, Cl(-)-rich solution enhanced cAMP-stimulated HCO(3)(-) secretion, as calculated from changes in luminal pH and volume. Luminal Cl(-) removal produced, after a transient small depolarization, sustained cell hyperpolarization of approximately 15 mV consistent with electrogenic Cl(-)/HCO(3)(-) exchange. The hyperpolarization was inhibited by H(2)DIDS and potentiated by CFTRinh-172. Interlobular ducts expressed mRNAs encoding CFTR, Slc26a6, and Slc26a3, as detected by RT-PCR. Thus Cl(-)-dependent apical HCO(3)(-) secretion in pancreatic duct is mediated predominantly by an Slc26a6-like Cl(-)/HCO(3)(-) exchanger and is accelerated by inhibition of CFTR. This study demonstrates functional coupling between Cftr and Slc26a6-like Cl(-)/HCO(3)(-) exchange activity in apical membrane of guinea pig pancreatic interlobular duct.
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Affiliation(s)
- A. K. Stewart
- Renal Division and Molecular and Vascular Medicine Unit, Beth Israel Deaconess Medical Center, and Department of Medicine, Harvard Medical School, Boston, Massachusetts; and Human Nutrition, Nagoya University Graduate School of Medicine, Showa-ku, Nagoya, Japan
| | - A. Yamamoto
- Renal Division and Molecular and Vascular Medicine Unit, Beth Israel Deaconess Medical Center, and Department of Medicine, Harvard Medical School, Boston, Massachusetts; and Human Nutrition, Nagoya University Graduate School of Medicine, Showa-ku, Nagoya, Japan
| | - M. Nakakuki
- Renal Division and Molecular and Vascular Medicine Unit, Beth Israel Deaconess Medical Center, and Department of Medicine, Harvard Medical School, Boston, Massachusetts; and Human Nutrition, Nagoya University Graduate School of Medicine, Showa-ku, Nagoya, Japan
| | - T. Kondo
- Renal Division and Molecular and Vascular Medicine Unit, Beth Israel Deaconess Medical Center, and Department of Medicine, Harvard Medical School, Boston, Massachusetts; and Human Nutrition, Nagoya University Graduate School of Medicine, Showa-ku, Nagoya, Japan
| | - S. L. Alper
- Renal Division and Molecular and Vascular Medicine Unit, Beth Israel Deaconess Medical Center, and Department of Medicine, Harvard Medical School, Boston, Massachusetts; and Human Nutrition, Nagoya University Graduate School of Medicine, Showa-ku, Nagoya, Japan
| | - H. Ishiguro
- Renal Division and Molecular and Vascular Medicine Unit, Beth Israel Deaconess Medical Center, and Department of Medicine, Harvard Medical School, Boston, Massachusetts; and Human Nutrition, Nagoya University Graduate School of Medicine, Showa-ku, Nagoya, Japan
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Pancreatic duct secretion: experimental methods, ion transport mechanisms and regulation. J Physiol Biochem 2008; 64:243-57. [DOI: 10.1007/bf03178846] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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Dorwart MR, Shcheynikov N, Yang D, Muallem S. The solute carrier 26 family of proteins in epithelial ion transport. Physiology (Bethesda) 2008; 23:104-14. [PMID: 18400693 DOI: 10.1152/physiol.00037.2007] [Citation(s) in RCA: 151] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Transepithelial Cl(-) and HCO(3)(-) transport is critically important for the function of all epithelia and, when altered or ablated, leads to a number of diseases, including cystic fibrosis, congenital chloride diarrhea, deafness, and hypotension (78, 111, 119, 126). HCO(3)(-) is the biological buffer that maintains acid-base balance, thereby preventing metabolic and respiratory acidosis (48). HCO(3)(-) also buffers the pH of the mucosal layers that line all epithelia, protecting them from injury (2). Being a chaotropic ion, HCO(3)(-) is essential for solubilization of ions and macromolecules such as mucins and digestive enzymes in secreted fluids. Most epithelia have a Cl(-)/HCO(3) exchange activity in the luminal membrane. The molecular nature of this activity remained a mystery for many years until the discovery of SLC26A3 and the realization that it is a member of a new family of Cl(-) and HCO(3)(-) transporters, the SLC26 family (73, 78). This review will highlight structural features, the functional diversity, and several regulatory aspects of the SLC26 transporters.
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Affiliation(s)
- Michael R Dorwart
- Department of Physiology, University of Texas Southwestern, Medical Center at Dallas, Dallas, Texas, USA
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21
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Novak I. Purinergic receptors in the endocrine and exocrine pancreas. Purinergic Signal 2007; 4:237-53. [PMID: 18368520 DOI: 10.1007/s11302-007-9087-6] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2007] [Accepted: 11/06/2007] [Indexed: 11/28/2022] Open
Abstract
The pancreas is a complex gland performing both endocrine and exocrine functions. In recent years there has been increasing evidence that both endocrine and exocrine cells possess purinergic receptors, which influence processes such as insulin secretion and epithelial ion transport. Most commonly, these processes have been viewed separately. In beta cells, stimulation of P2Y(1) receptors amplifies secretion of insulin in the presence of glucose. Nucleotides released from secretory granules could also contribute to autocrine/paracrine regulation in pancreatic islets. In addition to P2Y(1) receptors, there is also evidence for other P2 and adenosine receptors in beta cells (P2Y(2), P2Y(4), P2Y(6), P2X subtypes and A(1) receptors) and in glucagon-secreting alpha cells (P2X(7), A(2) receptors). In the exocrine pancreas, acini release ATP and ATP-hydrolysing and ATP-generating enzymes. P2 receptors are prominent in pancreatic ducts, and several studies indicate that P2Y(2), P2Y(4), P2Y(11), P2X(4) and P2X(7) receptors could regulate secretion, primarily by affecting Cl(-) and K(+) channels and intracellular Ca(2+) signalling. In order to understand the physiology of the whole organ, it is necessary to consider the full complement of purinergic receptors on different cells as well as the structural and functional relation between various cells within the whole organ. In addition to the possible physiological function of purinergic receptors, this review analyses whether the receptors could be potential therapeutic targets for drug design aimed at treatment of pancreatic diseases.
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Affiliation(s)
- I Novak
- Department of Biosciences, University of Copenhagen, August Krogh Building, Universitetsparken 13, 2100, Copenhagen Ø, Denmark,
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Hassan HA, Mentone S, Karniski LP, Rajendran VM, Aronson PS. Regulation of anion exchanger Slc26a6 by protein kinase C. Am J Physiol Cell Physiol 2007; 292:C1485-92. [PMID: 17151144 DOI: 10.1152/ajpcell.00447.2006] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
SLC26A6 (CFEX, PAT1) is an anion exchanger expressed in several tissues including renal proximal tubule, pancreatic duct, small intestine, liver, stomach, and heart. It has recently been reported that PKC activation inhibits A6-mediated Cl/HCO3exchange by disrupting binding of carbonic anhydrase to A6. However, A6 can operate in HCO3-independent exchange modes of physiological importance, as A6-mediated Cl/oxalate exchange plays important roles in proximal tubule NaCl reabsorption and intestinal oxalate secretion. We therefore examined whether PKC activation affects HCO3-independent exchange modes of Slc26a6 functionally expressed in Xenopus oocytes. We found that PKC activation inhibited Cl/formate exchange mediated by Slc26a6 but failed to inhibit the related anion exchanger pendrin (SLC26A4) under identical conditions. PKC activation inhibited Slc26a6-mediated Cl/formate exchange, Cl/oxalate exchange, and Cl/Cl exchange to a similar extent. The inhibitor sensitivity profile and the finding that PMA-induced inhibition was calcium independent suggested a potential role for PKC-δ. Indeed, the PKC-δ-selective inhibitor rottlerin significantly blocked PMA-induced inhibition of Slc26a6 activity. Localization of Slc26a6 by immunofluorescence microscopy demonstrated that exposure to PKC activation led to redistribution of Slc26a6 from the oocyte plasma membrane to the intracellular compartment immediately below it. We also observed that PMA decreased the pool of Slc26a6 available to surface biotinylation but had no effect on total Slc26a6 expression. The physiological significance of these findings was supported by the observation that PKC activation inhibited mouse duodenal oxalate secretion, an effect blocked by rottlerin. We conclude that multiple modes of anion exchange mediated by Slc26a6 are negatively regulated by PKC-δ activation.
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Affiliation(s)
- Hatim A Hassan
- Department of Internal Medicine, Yale University School of Medicine, New Haven, CT 06520, USA
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Hegyi P, Rakonczay Z. The inhibitory pathways of pancreatic ductal bicarbonate secretion. Int J Biochem Cell Biol 2006; 39:25-30. [PMID: 16996776 DOI: 10.1016/j.biocel.2006.07.011] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2006] [Revised: 06/26/2006] [Accepted: 07/31/2006] [Indexed: 10/24/2022]
Abstract
Pancreatic duct cells secrete the HCO(3)(-) ions found in pancreatic juice. While the regulatory pathways that stimulate pancreatic ductal HCO(3)(-) secretion are well described, little is known about inhibitory pathways, apart from the fact that they exist. Nevertheless, such inhibitory pathways may be physiologically important in terms of limiting the hydrostatic pressure within the lumen of the duct, and in terms switching off pancreatic secretion after a meal. Methionine encephalin, insulin, somatostatin, peptide YY, substance P, basolaterally applied adenosine triphosphate, arginine vasopressin, 5-hydroxytryptamine and epidermal growth factor have all been shown to inhibit fluid and/or HCO(3)(-) secretion from pancreatic ducts. Importantly, most of these inhibitors have been shown to reduce secretion in isolated pancreatic ducts, so they must act directly on the ductal epithelium. This brief review provides an overview of our current knowledge of the inhibitors, and inhibitory pathways of pancreatic ductal secretion. SIGNALLING NETWORK FACTS: Methionine encephalin, insulin, somatostatin, peptide YY, substance P, basolaterally applied adenosine triphosphate, arginine vasopressin, 5-hydroxytryptamine and epidermal growth factor have all been shown to inhibit fluid and/or HCO(3)(-) secretion from pancreatic ducts. The inhibition of pancreatic secretion can be mediated by indirect (decreased cholinergic or increased adrenergic stimulation, decreased release of stimulatory hormones) and direct (inhibitory hormone or neurotransmitter acting on the duct cells) mechanisms.
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Affiliation(s)
- Péter Hegyi
- First Department of Medicine, Faculty of Medicine, University of Szeged, Koranyi fasor 8-10, Szeged H6720, Hungary.
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Alvarez BV, Vilas GL, Casey JR. Metabolon disruption: a mechanism that regulates bicarbonate transport. EMBO J 2005; 24:2499-511. [PMID: 15990874 PMCID: PMC1176462 DOI: 10.1038/sj.emboj.7600736] [Citation(s) in RCA: 103] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2005] [Accepted: 06/08/2005] [Indexed: 02/07/2023] Open
Abstract
Carbonic anhydrases (CA) catalyze the reversible conversion of CO2 to HCO3-. Some bicarbonate transporters bind CA, forming a complex called a transport metabolon, to maximize the coupled catalytic/transport flux. SLC26A6, a plasma membrane Cl-/HCO3- exchanger with a suggested role in pancreatic HCO3- secretion, was found to bind the cytoplasmic enzyme CAII. Mutation of the identified CAII binding (CAB) site greatly reduced SLC26A6 activity, demonstrating the importance of the interaction. Regulation of SLC26A6 bicarbonate transport by protein kinase C (PKC) was investigated. Angiotensin II (AngII), which activates PKC, decreased Cl-/HCO3- exchange in cells coexpressing SLC26A6 and AT1a-AngII receptor. Activation of PKC reduced SLC26A6/CAII association in immunoprecipitates. Similarly, PKC activation displaced CAII from the plasma membrane, as monitored by immunofluorescence. Finally, mutation of a PKC site adjacent to the SLC26A6 CAB site rendered the transporter unresponsive to PKC. PKC therefore reduces CAII/SLC26A6 interaction, reducing bicarbonate transport rate. Taken together, our data support a mechanism for acute regulation of membrane transport: metabolon disruption.
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Affiliation(s)
- Bernardo V Alvarez
- Membrane Protein Research Group, Department of Physiology, University of Alberta, Edmonton, Alberta, Canada
| | - Gonzalo L Vilas
- Department of Cell Biology, University of Alberta, Edmonton, Alberta, Canada
| | - Joseph R Casey
- Membrane Protein Research Group, Department of Physiology, University of Alberta, Edmonton, Alberta, Canada
- Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada
- Department of Physiology, University of Alberta, Edmonton, Alberta, Canada T6G 2H7. Tel.: +1 780 492 7203; Fax: +1 780 492 8915; E-mail:
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