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The ClC-2 Chloride Channel Activator, Lubiprostone, Improves Intestinal Barrier Function in Biopsies from Crohn’s Disease but Not Ulcerative Colitis Patients. Pharmaceutics 2023; 15:pharmaceutics15030811. [PMID: 36986672 PMCID: PMC10053841 DOI: 10.3390/pharmaceutics15030811] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2022] [Revised: 02/05/2023] [Accepted: 02/22/2023] [Indexed: 03/06/2023] Open
Abstract
The prostone analog, lubiprostone, is approved to manage constipation-predominant irritable bowel syndrome. Lubiprostone also protects intestinal mucosal barrier function in animal models of colitis. The aim of this study was to determine if lubiprostone improves barrier properties in isolated colonic biopsies from Crohn’s disease (CD) and ulcerative colitis (UC) patients. Sigmoid colon biopsies from healthy subjects, CD and UC patients in remission, and CD patients with active disease were mounted in Ussing chambers. Tissues were treated with lubiprostone or vehicle to determine the effects on transepithelial electrical resistance (TER), FITC-dextran 4kD (FD4) permeability, and electrogenic ion transport responses to forskolin and carbachol. Localization of the tight junction protein, occludin, was determined by immunofluorescence. Lubiprostone significantly increased ion transport across control, CD and UC remission biopsies but not active CD. Lubiprostone selectively improved TER in both CD remission and active disease biopsies but not in control or UC biopsies. The improved TER was associated with increased membrane localization of occludin. Lubiprostone selectively improved barrier properties of biopsies from CD patients vs. UC and independent of an ion transport response. These data indicate that lubiprostone has potential efficacy in improving mucosal integrity in Crohn’s disease.
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Li X, Yu H, Guo W, Cheng M, Song Q, Ding L. Development and validation of a highly sensitive and selective LC-MS/MS method for the determination of 15-hydroxylubiprostone in human plasma: Application to a pharmacokinetic study in healthy Chinese volunteers. Xenobiotica 2022; 52:567-574. [PMID: 36129160 DOI: 10.1080/00498254.2022.2123751] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
Abstract
Lubiprostone, a derivative of prostaglandin E1, is the first chemical-type constipation treatment approved by FDA. Lubiprostone has low systemic exposure after oral administration. Therefore, it is recommended that 15-hydroxylubiprostone, which is a dominant active metabolite of lubiprostone, be used as the pharmacokinetic evaluation indicator. Due to the microdosage of the lubiprostone capsules, it is difficult to develop a highly sensitive bioanalytical method for 15-hydroxylubiprostone.In this study, a highly sensitive and selective liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) method has been established and fully validated for the quantification of 15-hydroxylubiprostone in human plasma, and the validated bioanalytical method has been applied to a pharmacokinetic study of lubiprostone capsules successfully.The pharmacokinetics of 15-hydroxylubiprostone were observed after fed administration in healthy Chinese volunteers. The Cmax and AUC0-t were 75.8 ± 57.6 pg/mL and 222 ± 68.0 pg·h/mL for 15-hydroxylubiprostone.This study investigated the pharmacokinetic properties of 15-hydroxylubiprostone under fed conditions in healthy Chinese volunteers and would provide clinical guidance for the application and further development of lubiprostone capsules.
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Affiliation(s)
- Xianjing Li
- Key Laboratory of Drug Quality Control and Pharmacovigilance, Ministry of Education, School of Pharmacy, China Pharmaceutical University, Nanjing 210009, China.,Department of pharmaceutical Analysis, China Pharmaceutical University, 24 Tongjiaxiang, Nanjing 210009, China
| | - Haitao Yu
- Nanjing Chia Tai Tianqing Pharmaceutical Co., Ltd, Nanjing 210038, China
| | - Wenjing Guo
- Key Laboratory of Drug Quality Control and Pharmacovigilance, Ministry of Education, School of Pharmacy, China Pharmaceutical University, Nanjing 210009, China.,Department of pharmaceutical Analysis, China Pharmaceutical University, 24 Tongjiaxiang, Nanjing 210009, China
| | - Minlu Cheng
- Nanjing Clinical Tech. Laboratories Inc., 18 Zhilan Road, Jiangning District, Nanjing 211100, China
| | - Qinxin Song
- Key Laboratory of Drug Quality Control and Pharmacovigilance, Ministry of Education, School of Pharmacy, China Pharmaceutical University, Nanjing 210009, China.,Department of pharmaceutical Analysis, China Pharmaceutical University, 24 Tongjiaxiang, Nanjing 210009, China
| | - Li Ding
- Key Laboratory of Drug Quality Control and Pharmacovigilance, Ministry of Education, School of Pharmacy, China Pharmaceutical University, Nanjing 210009, China.,Department of pharmaceutical Analysis, China Pharmaceutical University, 24 Tongjiaxiang, Nanjing 210009, China.,Nanjing Clinical Tech. Laboratories Inc., 18 Zhilan Road, Jiangning District, Nanjing 211100, China
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3
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Boger KD, Sheridan AE, Ziegler AL, Blikslager AT. Mechanisms and modeling of wound repair in the intestinal epithelium. Tissue Barriers 2022; 11:2087454. [PMID: 35695206 PMCID: PMC10161961 DOI: 10.1080/21688370.2022.2087454] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
Abstract
The intestinal epithelial barrier is susceptible to injury from insults, such as ischemia or infectious disease. The epithelium's ability to repair wounded regions is critical to maintaining barrier integrity. Mechanisms of intestinal epithelial repair can be studied with models that recapitulate the in vivo environment. This review focuses on in vitro injury models and intestinal cell lines utilized in such systems. The formation of artificial wounds in a controlled environment allows for the exploration of reparative physiology in cell lines modeling diverse aspects of intestinal physiology. Specifically, the use of intestinal cell lines, IPEC-J2, Caco-2, T-84, HT-29, and IEC-6, to model intestinal epithelium is discussed. Understanding the unique systems available for creating intestinal injury and the differences in monolayers used for in vitro work is essential for designing studies that properly capture relevant physiology for the study of intestinal wound repair.
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Affiliation(s)
- Kasey D Boger
- Comparative Medicine Institute, Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, USA
| | - Ana E Sheridan
- Comparative Medicine Institute, Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, USA
| | - Amanda L Ziegler
- Comparative Medicine Institute, Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, USA
| | - Anthony T Blikslager
- Comparative Medicine Institute, Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, USA
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4
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Oak AA, Chu T, Yottasan P, Chhetri PD, Zhu J, Du Bois J, Cil O. Lubiprostone is non-selective activator of cAMP-gated ion channels and Clc-2 has a minor role in its prosecretory effect in intestinal epithelial cells. Mol Pharmacol 2022; 102:MOLPHARM-AR-2022-000542. [PMID: 35680165 PMCID: PMC9341254 DOI: 10.1124/molpharm.122.000542] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2022] [Revised: 05/21/2022] [Accepted: 05/27/2022] [Indexed: 12/14/2022] Open
Abstract
Loss of prosecretory Cl- channel CFTR activity is considered as the key cause of gastrointestinal disorders in cystic fibrosis including constipation and meconium ileus. Clc-2 is proposed as an alternative Cl- channel in intestinal epithelia that can compensate for CFTR loss-of-function. Lubiprostone is an FDA-approved drug with Clc-2 activation as its presumed mechanism of action. However, relative contribution of Clc-2 in intestinal Cl- secretion and the mechanism of action of lubiprostone remain controversial due to lack of selective Clc-2 inhibitors. Using recently identified selective Clc-2 inhibitor AK-42, we characterized the roles of Clc-2 in Cl- secretion in human intestinal epithelial T84 cells. Clc-2 inhibitor AK-42 had minimal (15%) inhibitory effect on secretory short-circuit current (Isc) induced by cAMP agonists, where subsequently applied CFTR inhibitor (CFTRinh-172) caused 2-3 fold greater inhibition. Similarly, AK-42 inhibited lubiprostone-induced secretory Isc by 20%, whereas CFTRinh-172 caused 2-3 fold greater inhibition. In addition to increasing CFTR and Clc-2-mediated apical Cl- conductance, lubiprostone increased basolateral membrane K+ conductance, which was completely reversed by cAMP-activated K+ channel inhibitor BaCl2 All components of lubiprostone-induced secretion (Clc-2, CFTR and K+ channels) were inhibited by ~65% with the extracellular Ca2+-sensing receptor (CaSR) activator cinacalcet that stimulates cAMP hydrolysis. Lastly, EP4 prostaglandin receptor inhibitor GW627368 pretreatment inhibited lubiprostone-induced secretion by 40% without any effect on forskolin response. Our findings suggest that Clc-2 has minor role in cAMP-induced intestinal Cl- secretion; and lubiprostone is not a selective Clc-2 activator, but general activator of cAMP-gated ion channels in human intestinal epithelial cells. Significance Statement Cl- channel Clc-2 activation is the proposed mechanism of action of the FDA-approved constipation drug lubiprostone. Using first-in-class selective Clc-2 inhibitor AK-42, we showed that Clc-2 has minor contribution in intestinal Cl- secretion induced by lubiprostone and cAMP agonists. We also found that lubiprostone is a general activator of cAMP-gated ion channels in human intestinal epithelial cells (via EP4 receptors). Our findings clarify the roles of Clc-2 in intestinal Cl- secretion and elucidate the mechanism of action of approved-drug lubiprostone.
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Affiliation(s)
| | | | | | | | - Jie Zhu
- Stanford University, United States
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5
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Shaughnessy CA, Yadav S, Bratcher PE, Zeitlin PL. Receptor-mediated activation of CFTR via prostaglandin signaling pathways in the airway. Am J Physiol Lung Cell Mol Physiol 2022; 322:L305-L314. [PMID: 35020527 PMCID: PMC8858663 DOI: 10.1152/ajplung.00388.2021] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Cystic fibrosis (CF) is a genetic disease caused by mutations of the gene encoding a cAMP-activated Cl- channel, the cystic fibrosis transmembrane conductance regulator (CFTR). CFTR modulator therapies consist of small-molecule drugs that rescue mutant CFTR. Regimens of single or combinations of CFTR modulators still rely on endogenous levels of cAMP to regulate CFTR activity. We investigated CFTR activation by the natural mediator prostaglandin E2 (PGE2) and lubiprostone (a Food and Drug Administration-approved drug known to target prostaglandin receptors) and tested the hypothesis that receptor-mediated CFTR activators can be used in combination with currently available CFTR modulators to increase function of mutant CFTR. Primary-cultured airway epithelia were assayed in Ussing chambers. Experimental CFTR activators and established CFTR modulators were applied for 24 h and/or acutely and analyzed for their effect on CFTR activity as measured by changes in short-circuit current (ISC). In non-CF airway epithelia, acute application of lubiprostone and PGE2 activated CFTR to the levels comparable to forskolin (Fsk). Pretreatment (24 h) with antagonists to prostaglandin receptors EP2 and EP4 abolished the ability of lubiprostone to acutely activate CFTR. In F508del homozygous airway epithelia pretreated with the triple combination of elexacaftor, tezacaftor, and ivacaftor (ELEXA/TEZ/IVA; i.e., Trikafta), acute application of lubiprostone was able to maximally activate CFTR. Prolonged (24 h) cotreatment of F508del homozygous epithelia with ELEXA/TEZ/IVA and lubiprostone increased acute CFTR activation by ∼60% compared with the treatment with ELEXA/TEZ/IVA alone. This work establishes the feasibility of targeting prostaglandin receptors to activate CFTR on the airway epithelia and demonstrates that cotreatment with lubiprostone can further restore modulator-rescued CFTR.
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Affiliation(s)
| | - Sangya Yadav
- 1Department of Pediatrics, National Jewish Health, Denver, Colorado
| | - Preston E. Bratcher
- 1Department of Pediatrics, National Jewish Health, Denver, Colorado,2Department of Pediatrics, University of Colorado Denver, Anschutz Medical Campus, Aurora, Colorado
| | - Pamela L. Zeitlin
- 1Department of Pediatrics, National Jewish Health, Denver, Colorado,2Department of Pediatrics, University of Colorado Denver, Anschutz Medical Campus, Aurora, Colorado
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Korsós MM, Bellák T, Becskeházi E, Gál E, Veréb Z, Hegyi P, Venglovecz V. Mouse organoid culture is a suitable model to study esophageal ion transport mechanisms. Am J Physiol Cell Physiol 2021; 321:C798-C811. [PMID: 34524930 DOI: 10.1152/ajpcell.00295.2021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Accepted: 09/08/2021] [Indexed: 11/22/2022]
Abstract
Altered esophageal ion transport mechanisms play a key role in inflammatory and cancerous diseases of the esophagus, but epithelial ion processes have been less studied in the esophagus because of the lack of a suitable experimental model. In this study, we generated three-dimensional (3D) esophageal organoids (EOs) from two different mouse strains and characterized the ion transport processes of the EOs. EOs form a cell-filled structure with a diameter of 250-300 µm and were generated from epithelial stem cells as shown by FACS analysis. Using conventional PCR and immunostaining, the presence of Slc26a6 Cl-/HCO3- anion exchanger (AE), Na+/H+ exchanger (NHE), Na+/HCO3- cotransporter (NBC), cystic fibrosis transmembrane conductance regulator (CFTR), and anoctamin 1 Cl- channels was detected in EOs. Microfluorimetric techniques revealed high NHE, AE, and NBC activities, whereas that of CFTR was relatively low. In addition, inhibition of CFTR led to functional interactions between the major acid-base transporters and CFTR. We conclude that EOs provide a relevant and suitable model system for studying the ion transport mechanisms of esophageal epithelial cells, and they can be also used as preclinical tools to assess the effectiveness of novel therapeutic compounds in esophageal diseases associated with altered ion transport processes.
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Affiliation(s)
| | - Tamás Bellák
- Department of Anatomy, Histology and Embryology, University of Szeged, Szeged, Hungary
- BioTalentum Ltd., Gödöllő, Hungary
| | - Eszter Becskeházi
- Department of Pharmacology and Pharmacotherapy, University of Szeged, Szeged, Hungary
| | - Eleonóra Gál
- Department of Pharmacology and Pharmacotherapy, University of Szeged, Szeged, Hungary
| | - Zoltán Veréb
- Regenerative Medicine and Cellular Pharmacology Research Laboratory, Department of Dermatology and Allergology, University of Szeged, Szeged, Hungary
| | - Péter Hegyi
- First Department of Medicine, University of Szeged, Szeged, Hungary
- Szentágothai Research Centre, Institute for Translational Medicine, Medical School, University of Pécs, Pécs, Hungary
- Division of Gastroenterology, First Department of Medicine, Medical School, University of Pécs, Pécs, Hungary
| | - Viktória Venglovecz
- Department of Pharmacology and Pharmacotherapy, University of Szeged, Szeged, Hungary
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Catalán MA, Julio-Kalajzić F, Niemeyer MI, Cid LP, Sepúlveda FV. Short Chain Fatty Acids Effect on Chloride Channel ClC-2 as a Possible Mechanism for Lubiprostone Intestinal Action. Cells 2020; 9:cells9081781. [PMID: 32722648 PMCID: PMC7464869 DOI: 10.3390/cells9081781] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Revised: 07/22/2020] [Accepted: 07/23/2020] [Indexed: 01/22/2023] Open
Abstract
Lubiprostone, a 20-carbon synthetic fatty acid used for the treatment of constipation, is thought to act through an action on Cl− channel ClC-2. Short chain fatty acids (SCFAs) are produced and absorbed in the distal intestine. We explore whether SCFAs affect ClC-2, re-examine a possible direct effect of lubiprostone on ClC-2, and use mice deficient in ClC-2 to stringently address the hypothesis that the epithelial effect of lubiprostone targets this anion channel. Patch-clamp whole cell recordings of ClC-2 expressed in mammalian cells are used to assay SCFA and lubiprostone effects. Using chamber measurements of ion current in mice deficient in ClC-2 or CFTR channels served to analyze the target of lubiprostone in the distal intestinal epithelium. Intracellular SCFAs had a dual action on ClC-2, partially inhibiting conduction but, importantly, facilitating the voltage activation of ClC-2. Intra- or extracellular lubiprostone had no effect on ClC-2 currents. Lubiprostone elicited a secretory current across colonic epithelia that was increased in mice deficient in ClC-2, consistent with the channel’s proposed proabsorptive function, but absent from those deficient in CFTR. Whilst SCFAs might exert a physiological effect on ClC-2 as part of their known proabsorptive effect, ClC-2 plays no part in the lubiprostone intestinal effect that appears mediated by CFTR activation.
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Affiliation(s)
- Marcelo A. Catalán
- Centro de Estudios Científicos (CECs), Avenida Arturo Prat 514, Valdivia 5110466, Chile; (F.J.-K.); (M.I.N.); (L.P.C.)
- Instituto de Fisiología, Facultad de Medicina, Universidad Austral de Chile, Valdivia 5090000, Chile
- Correspondence: (M.A.C.); (F.V.S.); Tel.: +56-63-2221686 (M.A.C.)
| | - Francisca Julio-Kalajzić
- Centro de Estudios Científicos (CECs), Avenida Arturo Prat 514, Valdivia 5110466, Chile; (F.J.-K.); (M.I.N.); (L.P.C.)
| | - María Isabel Niemeyer
- Centro de Estudios Científicos (CECs), Avenida Arturo Prat 514, Valdivia 5110466, Chile; (F.J.-K.); (M.I.N.); (L.P.C.)
| | - Luis Pablo Cid
- Centro de Estudios Científicos (CECs), Avenida Arturo Prat 514, Valdivia 5110466, Chile; (F.J.-K.); (M.I.N.); (L.P.C.)
| | - Francisco V. Sepúlveda
- Centro de Estudios Científicos (CECs), Avenida Arturo Prat 514, Valdivia 5110466, Chile; (F.J.-K.); (M.I.N.); (L.P.C.)
- Correspondence: (M.A.C.); (F.V.S.); Tel.: +56-63-2221686 (M.A.C.)
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8
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Akita H, Yoshie S, Ishida T, Takeishi Y, Hazama A. Negative chronotropic and inotropic effects of lubiprostone on iPS cell-derived cardiomyocytes via activation of CFTR. BMC Complement Med Ther 2020; 20:118. [PMID: 32306956 PMCID: PMC7169008 DOI: 10.1186/s12906-020-02923-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Accepted: 04/07/2020] [Indexed: 11/10/2022] Open
Abstract
Background Lubiprostone (LBP) is a novel chloride channel opener that has been reported to activate chloride channel protein 2 (ClC-2) and cystic fibrosis transmembrane conductance regulator (CFTR). LBP facilitates fluid secretion by activating CFTR in the intestine and is used as a drug for treating chronic constipation. While ClC-2 and CFTR expression has been confirmed in cardiomyocytes (CMs), the effect of LBP on CMs has not yet been investigated. Thus, the present study aimed to investigate the effect of LBP on CMs using mouse-induced pluripotent stem (iPS) cell-derived CMs (iPS-CMs). Methods We induced mouse iPS cells into CMs through embryoid body (EB) formation. We compared the differentiated cells to CMs isolated from adult and fetal mice using gene expression, spontaneous beating rate, and contraction ratio analyses. Results Gene expression analysis revealed that, in the iPS-CMs, the mRNA expression of the undifferentiated cell markers Rex1 and Nanog decreased, whereas the expression of the unique cardiomyocyte markers cardiac troponin I (cTnI) and cardiac troponin T (cTNT), increased. Immunostaining showed that the localization of cTnI and connexin-43 in the iPS-CMs was similar to that in the primary fetal CMs (FCMs) and adult CMs (ACMs). LBP decreased the spontaneous beating rate of the iPS-CMs and FCMs, and decreased the contraction ratio of the iPS-CMs and ACMs. The reduction in the beating rate and contraction ratio caused by LBP was inhibited by glycine hydrazide (GlyH), which is a CFTR inhibitor. Conclusion These results suggest that LBP stimulates CFTR in CMs and that LBP has negative chronotropic and inotropic effects on CMs. LBP may be useful for treating cardiac diseases such as heart failure, ischemia, and arrhythmia.
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Affiliation(s)
- Hiraku Akita
- Department of Cardiovascular Medicine, Fukushima Medical University, Fukushima, Japan
| | - Susumu Yoshie
- Department of Cellular and Integrative Physiology, School of Medicine, Fukushima Medical University, 1 Hikarigaoka, Fukushima City, 960-1295, Japan
| | - Takafumi Ishida
- Department of Cardiovascular Medicine, Fukushima Medical University, Fukushima, Japan
| | - Yasuchika Takeishi
- Department of Cardiovascular Medicine, Fukushima Medical University, Fukushima, Japan
| | - Akihiro Hazama
- Department of Cellular and Integrative Physiology, School of Medicine, Fukushima Medical University, 1 Hikarigaoka, Fukushima City, 960-1295, Japan.
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Du C, Liu J, Wan H, Dong H, Zhao X. Functional Role of Basolateral ClC-2 Channels in the Regulation of Duodenal Anion Secretion in Mice. Dig Dis Sci 2019; 64:2527-2537. [PMID: 30874987 DOI: 10.1007/s10620-019-05578-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Accepted: 03/05/2019] [Indexed: 12/09/2022]
Abstract
BACKGROUND Although ClC-2 channels are important in colonic Cl- secretion, it is unclear about their roles in small intestinal anion secretion. Therefore, we sought to examine whether ClC-2 channels play important roles in anion secretion, particularly duodenal bicarbonate secretion (DBS). METHODS Duodenal mucosae from mice were stripped of seromuscular layers and mounted in Ussing chambers. Both duodenal short-circuit current (Isc) and HCO3- secretion in vitro were simultaneously recorded. DBS in vivo was measured by a CO2-sensitive electrode. RESULTS Lubiprostone, a selective ClC-2 activator, concentration-dependently increased both duodenal Isc and DBS only when applied basolaterally, but not when applied apically. Removal of extracellular Cl- abolished lubiprostone-induced duodenal Isc, but did not alter HCO3- secretion even in the presence of DIDS, a Cl-/HCO3- exchanger inhibitor. However, further addition of glibenclamide, a CFTR channel blocker, abolished lubiprostone-evoked HCO3- secretion. Moreover, lubiprostone-induced HCO3- secretion was impaired in CFTR-/- mice compared to wild-type littermates. Luminal perfusion of duodenal lumen with lubiprostone did not alter basal DBS in vivo, but lubiprostone (i.p.) was able to induce DBS, which was also significantly inhibited by Cd2+, a ClC-2 channel blocker. [Ca2+]cyt level, Ca2+-activated K+ channel- and cAMP-mediated duodenal Isc, and HCO3- secretion were unchanged by lubiprostone. CONCLUSIONS We have provided the first evidence for the novel functional role of basolateral ClC-2 channels in the regulation of duodenal anion secretion.
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Affiliation(s)
- Chao Du
- Department of Gastroenterology, Xinqiao Hospital, Army Medical University, Chongqing, 400037, China
| | - Jingjing Liu
- Department of Gastroenterology, Xinqiao Hospital, Army Medical University, Chongqing, 400037, China
| | - Hanxing Wan
- Department of Gastroenterology, Xinqiao Hospital, Army Medical University, Chongqing, 400037, China
| | - Hui Dong
- Department of Gastroenterology, Xinqiao Hospital, Army Medical University, Chongqing, 400037, China. .,Department of Medicine, School of Medicine, University of California, San Diego, CA, 92093, USA.
| | - Xiaoyan Zhao
- Department of Gastroenterology, Xinqiao Hospital, Army Medical University, Chongqing, 400037, China.
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10
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Rao MC. Physiology of Electrolyte Transport in the Gut: Implications for Disease. Compr Physiol 2019; 9:947-1023. [PMID: 31187895 DOI: 10.1002/cphy.c180011] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
We now have an increased understanding of the genetics, cell biology, and physiology of electrolyte transport processes in the mammalian intestine, due to the availability of sophisticated methodologies ranging from genome wide association studies to CRISPR-CAS technology, stem cell-derived organoids, 3D microscopy, electron cryomicroscopy, single cell RNA sequencing, transgenic methodologies, and tools to manipulate cellular processes at a molecular level. This knowledge has simultaneously underscored the complexity of biological systems and the interdependence of multiple regulatory systems. In addition to the plethora of mammalian neurohumoral factors and their cross talk, advances in pyrosequencing and metagenomic analyses have highlighted the relevance of the microbiome to intestinal regulation. This article provides an overview of our current understanding of electrolyte transport processes in the small and large intestine, their regulation in health and how dysregulation at multiple levels can result in disease. Intestinal electrolyte transport is a balance of ion secretory and ion absorptive processes, all exquisitely dependent on the basolateral Na+ /K+ ATPase; when this balance goes awry, it can result in diarrhea or in constipation. The key transporters involved in secretion are the apical membrane Cl- channels and the basolateral Na+ -K+ -2Cl- cotransporter, NKCC1 and K+ channels. Absorption chiefly involves apical membrane Na+ /H+ exchangers and Cl- /HCO3 - exchangers in the small intestine and proximal colon and Na+ channels in the distal colon. Key examples of our current understanding of infectious, inflammatory, and genetic diarrheal diseases and of constipation are provided. © 2019 American Physiological Society. Compr Physiol 9:947-1023, 2019.
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Affiliation(s)
- Mrinalini C Rao
- Department of Physiology and Biophysics, University of Illinois at Chicago, Chicago, Illinois, USA
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11
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Sardi C, Garetto S, Capone L, Galbiati V, Racchi M, Govoni S, Giovagnoni E, Lucci J. Experimental Paradigm for the Assessment of the Non-pharmacological Mechanism of Action in Medical Device Classification: The Example of Glycerine as Laxative. Front Pharmacol 2018; 9:1410. [PMID: 30581385 PMCID: PMC6292988 DOI: 10.3389/fphar.2018.01410] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Accepted: 11/16/2018] [Indexed: 01/19/2023] Open
Abstract
The evolution of medical devices has led to the introduction of medical devices that include "substances" and which, due to their presentation and sites of application may resemble medicinal products. The difference between substance-based medical devices and medicinal products lies in the proper definition of the principal mechanism of action. The major problem at the moment is the lack of a proper procedure for the demonstration of a mechanism that is "not pharmacological, immunological or metabolic." We aimed to design an experimental set up to demonstrate the difference between the mechanism of action of two substances used commonly for the treatment of constipation, lubiprostone (example of medicinal product) and glycerine (example of medical device). By implementing cellular models and molecular analyses we demonstrate the difference in their mechanism of action. This set up can be considered an example on the possibility to define a paradigm for the case by case study of the mechanism of action of substances and combination of substances in medical devices.
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Affiliation(s)
| | | | | | - Valentina Galbiati
- Department of Environmental Science and Policies, Università degli Studi di Milan, Milan, Italy
| | - Marco Racchi
- Dipartimento di Scienze del Farmaco, Università degli Studi di Pavia, Pavia, Italy
| | - Stefano Govoni
- Dipartimento di Scienze del Farmaco, Università degli Studi di Pavia, Pavia, Italy
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Jung D, Alshaikh A, Ratakonda S, Bashir M, Amin R, Jeon S, Stevens J, Sharma S, Ahmed W, Musch M, Hassan H. Adenosinergic signaling inhibits oxalate transport by human intestinal Caco2-BBE cells through the A 2B adenosine receptor. Am J Physiol Cell Physiol 2018; 315:C687-C698. [PMID: 30020825 DOI: 10.1152/ajpcell.00024.2017] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Most kidney stones (KS) are composed of calcium oxalate, and small increases in urine oxalate affect the stone risk. Intestinal oxalate secretion mediated by anion exchanger SLC26A6 (PAT1) plays a crucial role in limiting net absorption of ingested oxalate, thereby preventing hyperoxaluria and related KS, reflecting the importance of understanding regulation of intestinal oxalate transport. We previously showed that ATP and UTP inhibit oxalate transport by human intestinal Caco2-BBE cells (C2). Since ATP is rapidly degraded to adenosine (ADO), we examined whether intestinal oxalate transport is regulated by ADO. We measured [14C]oxalate uptake in the presence of an outward Cl gradient as an assay of Cl-oxalate exchange activity, ≥49% of which is PAT1-mediated in C2 cells. We found that ADO significantly inhibited oxalate transport by C2 cells, an effect completely blocked by the nonselective ADO receptor antagonist 8- p-sulfophenyltheophylline. ADO also significantly inhibited oxalate efflux by C2 cells, which is important since PAT1 mediates oxalate efflux in vivo. Using pharmacological antagonists and A2B adenosine receptor (A2B AR) siRNA knockdown studies, we observed that ADO inhibits oxalate transport through the A2B AR, phospholipase C, and PKC. ADO inhibits oxalate transport by reducing PAT1 surface expression as shown by biotinylation studies. We conclude that ADO inhibits oxalate transport by lowering PAT1 surface expression in C2 cells through signaling pathways including the A2B AR, PKC, and phospholipase C. Given higher ADO levels and overexpression of the A2B AR in inflammatory bowel disease (IBD), our findings have potential relevance to pathophysiology of IBD-associated hyperoxaluria and related KS.
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Affiliation(s)
- Daniel Jung
- Department of Medicine, The University of Chicago , Chicago, Illinois
| | - Altayeb Alshaikh
- Department of Medicine, The University of Chicago , Chicago, Illinois
| | | | - Mohamed Bashir
- Department of Medicine, The University of Chicago , Chicago, Illinois
| | - Ruhul Amin
- Department of Medicine, The University of Chicago , Chicago, Illinois
| | - Sohee Jeon
- Department of Medicine, The University of Chicago , Chicago, Illinois
| | - Jan Stevens
- Department of Medicine, The University of Chicago , Chicago, Illinois
| | - Sapna Sharma
- Department of Medicine, The University of Chicago , Chicago, Illinois
| | - Wahaj Ahmed
- Department of Medicine, The University of Chicago , Chicago, Illinois
| | - Mark Musch
- Department of Medicine, The University of Chicago , Chicago, Illinois
| | - Hatim Hassan
- Department of Medicine, The University of Chicago , Chicago, Illinois
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13
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Jentsch TJ, Pusch M. CLC Chloride Channels and Transporters: Structure, Function, Physiology, and Disease. Physiol Rev 2018; 98:1493-1590. [DOI: 10.1152/physrev.00047.2017] [Citation(s) in RCA: 214] [Impact Index Per Article: 35.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
CLC anion transporters are found in all phyla and form a gene family of eight members in mammals. Two CLC proteins, each of which completely contains an ion translocation parthway, assemble to homo- or heteromeric dimers that sometimes require accessory β-subunits for function. CLC proteins come in two flavors: anion channels and anion/proton exchangers. Structures of these two CLC protein classes are surprisingly similar. Extensive structure-function analysis identified residues involved in ion permeation, anion-proton coupling and gating and led to attractive biophysical models. In mammals, ClC-1, -2, -Ka/-Kb are plasma membrane Cl−channels, whereas ClC-3 through ClC-7 are 2Cl−/H+-exchangers in endolysosomal membranes. Biological roles of CLCs were mostly studied in mammals, but also in plants and model organisms like yeast and Caenorhabditis elegans. CLC Cl−channels have roles in the control of electrical excitability, extra- and intracellular ion homeostasis, and transepithelial transport, whereas anion/proton exchangers influence vesicular ion composition and impinge on endocytosis and lysosomal function. The surprisingly diverse roles of CLCs are highlighted by human and mouse disorders elicited by mutations in their genes. These pathologies include neurodegeneration, leukodystrophy, mental retardation, deafness, blindness, myotonia, hyperaldosteronism, renal salt loss, proteinuria, kidney stones, male infertility, and osteopetrosis. In this review, emphasis is laid on biophysical structure-function analysis and on the cell biological and organismal roles of mammalian CLCs and their role in disease.
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Affiliation(s)
- Thomas J. Jentsch
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP) and Max-Delbrück-Centrum für Molekulare Medizin (MDC), Berlin, Germany; and Istituto di Biofisica, Consiglio Nazionale delle Ricerche, Genova, Italy
| | - Michael Pusch
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP) and Max-Delbrück-Centrum für Molekulare Medizin (MDC), Berlin, Germany; and Istituto di Biofisica, Consiglio Nazionale delle Ricerche, Genova, Italy
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14
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Sarathy J, Detloff SJ, Ao M, Khan N, French S, Sirajuddin H, Nair T, Rao MC. The Yin and Yang of bile acid action on tight junctions in a model colonic epithelium. Physiol Rep 2018; 5:e13294. [PMID: 28554966 PMCID: PMC5449568 DOI: 10.14814/phy2.13294] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Revised: 04/28/2017] [Accepted: 05/01/2017] [Indexed: 12/14/2022] Open
Abstract
Gastrointestinal epithelial barrier loss due to tight junction (TJ) dysfunction and bile acid‐induced diarrhea are common in patients with inflammatory diseases. Although excess colonic bile acids are known to alter mucosal permeability, few studies have compared the effects of specific bile acids on TJ function. We report that the primary bile acid, chenodeoxycholic acid (CDCA), and its 7α‐dehydroxylated derivative, lithocholic acid (LCA) have opposite effects on epithelial integrity in human colonic T84 cells. CDCA decreased transepithelial barrier resistance (pore) and increased paracellular 10 kDa dextran permeability (leak), effects that were enhanced by proinflammatory cytokines (PiC [ng/mL]: TNFα[10] + IL‐1ß[10] + IFNγ[30]). CDCA reversed the cation selectivity of the monolayer and decreased intercellular adhesion. In contrast, LCA alone did not alter any of these parameters, but attenuated the effects of CDCA ± PiC on paracellular permeability. CDCA, but not PiC, decreased occludin and not claudin‐2 protein expression; CDCA also decreased occludin localization. LCA ± CDCA had no effects on occludin or claudin expression/localization. While PiC and CDCA increased IL‐8 production, LCA reduced both basal and PiC ± CDCA‐induced IL‐8 production. TNFα + IL1ß increased IFNγ, which was enhanced by CDCA and attenuated by LCA. CDCA±PiC increased production of reactive oxygen species (ROS) that was attenuated by LCA. Finally, scavenging ROS attenuated CDCA's leak, but not pore actions, and LCA enhanced this effect. Thus, in T84 cells, CDCA plays a role in the inflammatory response causing barrier dysfunction, while LCA restores barrier integrity. Understanding the interplay of LCA, CDCA, and PiC could lead to innovative therapeutic strategies for inflammatory and diarrheal diseases.
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Affiliation(s)
- Jayashree Sarathy
- Department of Physiology and Biophysics, University of Illinois at Chicago, Chicago, Illinois.,Department of Biological Sciences, Benedictine University, Lisle, Illinois
| | - Sally Jo Detloff
- Department of Biological Sciences, Benedictine University, Lisle, Illinois
| | - Mei Ao
- Department of Physiology and Biophysics, University of Illinois at Chicago, Chicago, Illinois
| | - Nabihah Khan
- Department of Biological Sciences, Benedictine University, Lisle, Illinois
| | - Sydney French
- Department of Biological Sciences, Benedictine University, Lisle, Illinois
| | - Hafsa Sirajuddin
- Department of Biological Sciences, Benedictine University, Lisle, Illinois
| | - Tanushree Nair
- Department of Biological Sciences, Benedictine University, Lisle, Illinois
| | - Mrinalini C Rao
- Department of Physiology and Biophysics, University of Illinois at Chicago, Chicago, Illinois
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15
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Sinagra E, Morreale GC, Mohammadian G, Fusco G, Guarnotta V, Tomasello G, Cappello F, Rossi F, Amvrosiadis G, Raimondo D. New therapeutic perspectives in irritable bowel syndrome: Targeting low-grade inflammation, immuno-neuroendocrine axis, motility, secretion and beyond. World J Gastroenterol 2017; 23:6593-6627. [PMID: 29085207 PMCID: PMC5643283 DOI: 10.3748/wjg.v23.i36.6593] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Revised: 04/15/2017] [Accepted: 07/04/2017] [Indexed: 02/06/2023] Open
Abstract
Irritable bowel syndrome (IBS) is a chronic, recurring, and remitting functional disorder of the gastrointestinal tract characterized by abdominal pain, distention, and changes in bowel habits. Although there are several drugs for IBS, effective and approved treatments for one or more of the symptoms for various IBS subtypes are needed. Improved understanding of pathophysiological mechanisms such as the role of impaired bile acid metabolism, neurohormonal regulation, immune dysfunction, the epithelial barrier and the secretory properties of the gut has led to advancements in the treatment of IBS. With regards to therapies for restoring intestinal permeability, multiple studies with prebiotics and probiotics are ongoing, even if to date their efficacy has been limited. In parallel, much progress has been made in targeting low-grade inflammation, especially through the introduction of drugs such as mesalazine and rifaximin, even if a better knowledge of the mechanisms underlying the low-grade inflammation in IBS may allow the design of clinical trials that test the efficacy and safety of such drugs. This literature review aims to summarize the findings related to new and investigational therapeutic agents for IBS, most recently developed in preclinical as well as Phase 1 and Phase 2 clinical studies.
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Affiliation(s)
- Emanuele Sinagra
- Gastroenterology and Endoscopy Unit, Fondazione Istituto Giuseppe Giglio, Contrada Pietra Pollastra Pisciotto, 90015 Cefalù, Italy
- Euro-Mediterranean Institute of Science and Technology, 90100 Palermo, Italy
- Department of Experimental Biomedicine and Clinical Neuroscience, Section of Human Anatomy, University of Palermo, 90100 Palermo, Italy
| | | | - Ghazaleh Mohammadian
- Department of Medicine, Division of Gastroenterology and Hepatology, Karolinska Institutet, Karolinska University Hospital, Huddinge, 17176 Stockholm, Sweden
| | - Giorgio Fusco
- Unit of Internal Medicine, Ospedali Riuniti Villa Sofia-Vincenzo Cervello, 90100 Palermo, Italy
| | - Valentina Guarnotta
- Section of Cardio-Respiratory and Endocrine-Metabolic Diseases, Biomedical Department of Internal and Specialist Medicine, University of Palermo, Palermo 90127, Italy
| | - Giovanni Tomasello
- Euro-Mediterranean Institute of Science and Technology, 90100 Palermo, Italy
- Department of Experimental Biomedicine and Clinical Neuroscience, Section of Human Anatomy, University of Palermo, 90100 Palermo, Italy
| | - Francesco Cappello
- Euro-Mediterranean Institute of Science and Technology, 90100 Palermo, Italy
- Department of Experimental Biomedicine and Clinical Neuroscience, Section of Human Anatomy, University of Palermo, 90100 Palermo, Italy
| | - Francesca Rossi
- Gastroenterology and Endoscopy Unit, Fondazione Istituto Giuseppe Giglio, Contrada Pietra Pollastra Pisciotto, 90015 Cefalù, Italy
| | - Georgios Amvrosiadis
- Unit of Gastroenterology, Ospedali Riuniti Villa Sofia-Vincenzo Cervello, 90100 Palermo, Italy
| | - Dario Raimondo
- Gastroenterology and Endoscopy Unit, Fondazione Istituto Giuseppe Giglio, Contrada Pietra Pollastra Pisciotto, 90015 Cefalù, Italy
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16
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Wang H, Xu M, Kong Q, Sun P, Yan F, Tian W, Wang X. Research and progress on ClC‑2 (Review). Mol Med Rep 2017; 16:11-22. [PMID: 28534947 PMCID: PMC5482133 DOI: 10.3892/mmr.2017.6600] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2016] [Accepted: 02/13/2017] [Indexed: 12/22/2022] Open
Abstract
Chloride channel 2 (ClC-2) is one of the nine mammalian members of the ClC family. The present review discusses the molecular properties of ClC‑2, including CLCN2, ClC‑2 promoter and the structural properties of ClC‑2 protein; physiological properties; functional properties, including the regulation of cell volume. The effects of ClC‑2 on the digestive, respiratory, circulatory, nervous and optical systems are also discussed, in addition to the mechanisms involved in the regulation of ClC‑2. The review then discusses the diseases associated with ClC‑2, including degeneration of the retina, Sjögren's syndrome, age‑related cataracts, degeneration of the testes, azoospermia, lung cancer, constipation, repair of impaired intestinal mucosa barrier, leukemia, cystic fibrosis, leukoencephalopathy, epilepsy and diabetes mellitus. It was concluded that future investigations of ClC‑2 are likely to be focused on developing specific drugs, activators and inhibitors regulating the expression of ClC‑2 to treat diseases associated with ClC‑2. The determination of CLCN2 is required to prevent and treat several diseases associated with ClC‑2.
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Affiliation(s)
- Hongwei Wang
- Department of Ophthalmology, People's Hospital of Jingjiang, Jingjiang, Jiangsu 214500, P.R. China
| | - Minghui Xu
- Library, Qiqihar Medical University, Qiqihar, Heilongjiang 161006, P.R. China
| | - Qingjie Kong
- School of Computer Science and Information Technology, Northeast Normal University, Changchun, Jilin 130024, P.R. China
| | - Peng Sun
- Department of Ophthalmology, The First Affiliated Hospital of Jiamusi University, Jiamusi, Heilongjiang 154000, P.R. China
| | - Fengyun Yan
- Assets Division, Harbin University of Science and Technology, Harbin, Heilongjiang 150080, P.R. China
| | - Wenying Tian
- Library, Qiqihar Medical University, Qiqihar, Heilongjiang 161006, P.R. China
| | - Xin Wang
- Library, Qiqihar Medical University, Qiqihar, Heilongjiang 161006, P.R. China
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17
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Cuppoletti J, Tewari KP, Chakrabarti J, Malinowska DH. Identification of the fatty acid activation site on human ClC-2. Am J Physiol Cell Physiol 2017; 312:C707-C723. [PMID: 28424169 DOI: 10.1152/ajpcell.00267.2016] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2016] [Revised: 04/11/2017] [Accepted: 04/11/2017] [Indexed: 01/26/2023]
Abstract
Fatty acids (including lubiprostone and cobiprostone) are human ClC-2 (hClC-2) Cl- channel activators. Molecular and cellular mechanisms underlying this activation were examined. Role of a four-amino acid PKA activation site, RGET691, of hClC-2 was investigated using wild-type (WT) and mutant (AGET, RGEA, and AGAA) hClC-2 expressed in 293EBNA cells as well as involvement of PKA, intracellular cAMP concentration ([cAMP]i), EP2, or EP4 receptor agonist activity. All fatty acids [lubiprostone, cobiprostone, eicosatetraynoic acid (ETYA), oleic acid, and elaidic acid] caused significant rightward shifts in concentration-dependent Cl- current activation (increasing EC50s) with mutant compared with WT hClC-2 channels, without changing time and voltage dependence, current-voltage rectification, or methadone inhibition of the channel. As with lubiprostone, cobiprostone activation of hClC-2 occurred with PKA inhibitor (myristoylated protein kinase inhibitor) present or when using double PKA activation site (RRAA655/RGEA691) mutant. Cobiprostone did not activate human CFTR. Fatty acids did not increase [cAMP]i in hClC-2/293EBNA or T84 cells. Using T84 CFTR knockdown cells, cobiprostone increased hClC-2 Cl- currents without increasing [cAMP]i, while PGE2 and forskolin-IBMX increased both. Fatty acids were not agonists of EP2 or EP4 receptors. L-161,982, a supposed EP4-selective inhibitor, had no effect on lubiprostone-activated hClC-2 Cl- currents but significantly decreased T84 cell barrier function measured by transepithelial resistance and fluorescent dextran transepithelial movement. The present findings show that RGET691 of hClC-2 (possible binding site) plays an important functional role in fatty acid activation of hClC-2. PKA, [cAMP]i, and EP2 or EP4 receptors are not involved. These studies provide the molecular basis for fatty acid regulation of hClC-2.
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Affiliation(s)
- John Cuppoletti
- Department of Molecular and Cellular Physiology, University of Cincinnati, Cincinnati, Ohio
| | - Kirti P Tewari
- Department of Molecular and Cellular Physiology, University of Cincinnati, Cincinnati, Ohio
| | - Jayati Chakrabarti
- Department of Molecular and Cellular Physiology, University of Cincinnati, Cincinnati, Ohio
| | - Danuta H Malinowska
- Department of Molecular and Cellular Physiology, University of Cincinnati, Cincinnati, Ohio
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18
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Arvans D, Jung YC, Antonopoulos D, Koval J, Granja I, Bashir M, Karrar E, Roy-Chowdhury J, Musch M, Asplin J, Chang E, Hassan H. Oxalobacter formigenes-Derived Bioactive Factors Stimulate Oxalate Transport by Intestinal Epithelial Cells. J Am Soc Nephrol 2016; 28:876-887. [PMID: 27738124 DOI: 10.1681/asn.2016020132] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2016] [Accepted: 08/13/2016] [Indexed: 12/12/2022] Open
Abstract
Hyperoxaluria is a major risk factor for kidney stones and has no specific therapy, although Oxalobacter formigenes colonization is associated with reduced stone risk. O. formigenes interacts with colonic epithelium and induces colonic oxalate secretion, thereby reducing urinary oxalate excretion, via an unknown secretagogue. The difficulties in sustaining O. formigenes colonization underscore the need to identify the derived factors inducing colonic oxalate secretion. We therefore evaluated the effects of O. formigenes culture conditioned medium (CM) on apical 14C-oxalate uptake by human intestinal Caco-2-BBE cells. Compared with control medium, O. formigenes CM significantly stimulated oxalate uptake (>2.4-fold), whereas CM from Lactobacillus acidophilus did not. Treating the O. formigenes CM with heat or pepsin completely abolished this bioactivity, and selective ultrafiltration of the CM revealed that the O. formigenes-derived factors have molecular masses of 10-30 kDa. Treatment with the protein kinase A inhibitor H89 or the anion exchange inhibitor 4,4'-diisothiocyano-2,2'-stilbenedisulfonic acid completely blocked the CM-induced oxalate transport. Knockdown of the oxalate transporter SLC26A6 also significantly restricted the induction of oxalate transport by CM. In a mouse model of primary hyperoxaluria type 1, rectal administration of O. formigenes CM significantly reduced (>32.5%) urinary oxalate excretion and stimulated (>42%) distal colonic oxalate secretion. We conclude that O. formigenes-derived bioactive factors stimulate oxalate transport in intestinal cells through mechanisms including PKA activation. The reduction in urinary oxalate excretion in hyperoxaluric mice treated with O. formigenes CM reflects the in vivo retention of biologic activity and the therapeutic potential of these factors.
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Affiliation(s)
- Donna Arvans
- Department of Medicine, The University of Chicago, Chicago, Illinois
| | - Yong-Chul Jung
- Department of Medicine, The University of Chicago, Chicago, Illinois
| | - Dionysios Antonopoulos
- Department of Medicine, The University of Chicago, Chicago, Illinois.,Biosciences Division, Argonne National Laboratory, Argonne, Illinois
| | - Jason Koval
- Biosciences Division, Argonne National Laboratory, Argonne, Illinois
| | - Ignacio Granja
- Litholink Corporation, Laboratory Corporation of America Holdings, Chicago, Illinois; and
| | - Mohamed Bashir
- Department of Medicine, The University of Chicago, Chicago, Illinois
| | - Eltayeb Karrar
- Department of Medicine, The University of Chicago, Chicago, Illinois
| | | | - Mark Musch
- Department of Medicine, The University of Chicago, Chicago, Illinois
| | - John Asplin
- Litholink Corporation, Laboratory Corporation of America Holdings, Chicago, Illinois; and
| | - Eugene Chang
- Department of Medicine, The University of Chicago, Chicago, Illinois
| | - Hatim Hassan
- Department of Medicine, The University of Chicago, Chicago, Illinois;
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19
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Domingue JC, Ao M, Sarathy J, Rao MC. Chenodeoxycholic acid requires activation of EGFR, EPAC, and Ca2+ to stimulate CFTR-dependent Cl- secretion in human colonic T84 cells. Am J Physiol Cell Physiol 2016; 311:C777-C792. [PMID: 27558159 DOI: 10.1152/ajpcell.00168.2016] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2016] [Accepted: 08/19/2016] [Indexed: 12/12/2022]
Abstract
Bile acids are known to initiate intricate signaling events in a variety of tissues, primarily in the liver and gastrointestinal tract. Of the known bile acids, only the 7α-dihydroxy species, deoxycholic acid and chenodeoxycholic acid (CDCA), and their conjugates, activate processes that stimulate epithelial Cl- secretion. We have previously published that CDCA acts in a rapid manner to stimulate colonic ion secretion via protein kinase A (PKA)-mediated activation of the dominant Cl- channel, the cystic fibrosis transmembrane conductance regulator (CFTR) (Ao M, Sarathy J, Domingue J, Alrefai WA, and Rao MC. Am J Physiol Cell Physiol 305: C447-C456, 2013); however, PKA signaling did not account for the entire CDCA response. Here we show that in human colonic T84 cells, CDCA's induction of CFTR activity, measured as changes in short-circuit current (Isc), is dependent on epidermal growth factor receptor (EGFR) activation and does not involve the bile acid receptors TGR5 or farnesoid X receptor. CDCA activation of Cl- secretion does not require Src, mitogen-activated protein kinases, or phosphoinositide 3-kinase downstream of EGFR but does require an increase in cytosolic Ca2+ In addition to PKA signaling, we found that the CDCA response requires the novel involvement of the exchange protein directly activated by cAMP (EPAC). EPAC is a known hub for cAMP and Ca2+ cross talk. Downstream of EPAC, CDCA activates Rap2, and changes in free cytosolic Ca2+ were dependent on both EPAC and EGFR activation. This study establishes the complexity of CDCA signaling in the colonic epithelium and shows the contribution of EGFR, EPAC, and Ca2+ in CDCA-induced activation of CFTR-dependent Cl- secretion.
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Affiliation(s)
- Jada C Domingue
- Department of Physiology and Biophysics, University of Illinois at Chicago, Chicago, Illinois
| | - Mei Ao
- Department of Physiology and Biophysics, University of Illinois at Chicago, Chicago, Illinois
| | - Jayashree Sarathy
- Department of Physiology and Biophysics, University of Illinois at Chicago, Chicago, Illinois.,Department of Biology, Benedictine University, Lisle, Illinois
| | - Mrinalini C Rao
- Department of Physiology and Biophysics, University of Illinois at Chicago, Chicago, Illinois; .,Department of Medicine, University of Illinois at Chicago, Chicago, Illinois; and
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20
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Abstract
Constipation is common in the general population and for those on opioids and/or who are suffering from advanced cancer. Self-management consists of dietary changes, exercise, and laxatives. However, responses to self-management efforts are often inadequate to relieve the subjective and objective experience of constipation. Multiple new anti-constipating medications have recently been tested in randomized trials and the following are available commercially: probiotics, prucalopride, lubiprostone, linaclotide, elobixibat, antidepressants, methylnaltrexone, alvimopan, and naloxegol. This review will discuss the evidence-based benefits of these medications and outline an approach to managing constipation.
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Affiliation(s)
- Mellar Davis
- Cleveland Clinic Lerner School of Medicine Case, Western Reserve University, 9500 Euclid Avenue, T34, Cleveland, OH, 44195, USA.
- Clinical Fellowship Program, Cleveland, OH, USA.
- Palliative Medicine and Supportive Oncology Services, Taussig Cancer Institute, Cleveland, OH, USA.
| | - Pamela Gamier
- Cleveland Clinic Lerner School of Medicine Case, Western Reserve University, 9500 Euclid Avenue, T34, Cleveland, OH, 44195, USA
- Clinical Fellowship Program, Cleveland, OH, USA
- Palliative Medicine and Supportive Oncology Services, Taussig Cancer Institute, Cleveland, OH, USA
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21
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Ao M, Domingue JC, Khan N, Javed F, Osmani K, Sarathy J, Rao MC. Lithocholic acid attenuates cAMP-dependent Cl- secretion in human colonic epithelial T84 cells. Am J Physiol Cell Physiol 2016; 310:C1010-23. [PMID: 27076617 DOI: 10.1152/ajpcell.00350.2015] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2015] [Accepted: 04/12/2016] [Indexed: 01/14/2023]
Abstract
Bile acids (BAs) play a complex role in colonic fluid secretion. We showed that dihydroxy BAs, but not the monohydroxy BA lithocholic acid (LCA), stimulate Cl(-) secretion in human colonic T84 cells (Ao M, Sarathy J, Domingue J, Alrefai WA, Rao MC. Am J Physiol Cell Physiol 305: C447-C456, 2013). In this study, we explored the effect of LCA on the action of other secretagogues in T84 cells. While LCA (50 μM, 15 min) drastically (>90%) inhibited FSK-stimulated short-circuit current (Isc), it did not alter carbachol-stimulated Isc LCA did not alter basal Isc, transepithelial resistance, cell viability, or cytotoxicity. LCA's inhibitory effect was dose dependent, acted faster from the apical membrane, rapid, and not immediately reversible. LCA also prevented the Isc stimulated by the cAMP-dependent secretagogues 8-bromo-cAMP, lubiprostone, or chenodeoxycholic acid (CDCA). The LCA inhibitory effect was BA specific, since CDCA, cholic acid, or taurodeoxycholic acid did not alter FSK or carbachol action. While LCA alone had no effect on intracellular cAMP concentration ([cAMP]i), it decreased FSK-stimulated [cAMP]i by 90%. Although LCA caused a small increase in intracellular Ca(2+) concentration ([Ca(2+)]i), chelation by BAPTA-AM did not reverse LCA's effect on Isc LCA action does not appear to involve known BA receptors, farnesoid X receptor, vitamin D receptor, muscarinic acetylcholine receptor M3, or bile acid-specific transmembrane G protein-coupled receptor 5. LCA significantly increased ERK1/2 phosphorylation, which was completely abolished by the MEK inhibitor PD-98059. Surprisingly PD-98059 did not reverse LCA's effect on Isc Finally, although LCA had no effect on basal Isc, nystatin permeabilization studies showed that LCA both stimulates an apical cystic fibrosis transmembrane conductance regulator Cl(-) current and inhibits a basolateral K(+) current. In summary, 50 μM LCA greatly inhibits cAMP-stimulated Cl(-) secretion, making low doses of LCA of potential therapeutic interest for diarrheal diseases.
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Affiliation(s)
- Mei Ao
- Department of Physiology and Biophysics, University of Illinois at Chicago, Chicago, Illinois
| | - Jada C Domingue
- Department of Physiology and Biophysics, University of Illinois at Chicago, Chicago, Illinois
| | - Nabihah Khan
- Department of Biology, Benedictine University, Lisle, Illinois
| | - Fatima Javed
- Department of Biology, Benedictine University, Lisle, Illinois
| | - Kashif Osmani
- Department of Physiology and Biophysics, University of Illinois at Chicago, Chicago, Illinois
| | - Jayashree Sarathy
- Department of Physiology and Biophysics, University of Illinois at Chicago, Chicago, Illinois; Department of Biology, Benedictine University, Lisle, Illinois
| | - Mrinalini C Rao
- Department of Physiology and Biophysics, University of Illinois at Chicago, Chicago, Illinois; Department of Medicine, University of Illinois at Chicago, Chicago, Illinois; and
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22
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Pharmaceutical Activation or Genetic Absence of ClC-2 Alters Tight Junctions During Experimental Colitis. Inflamm Bowel Dis 2015; 21:2747-57. [PMID: 26332307 DOI: 10.1097/mib.0000000000000550] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
BACKGROUND We have previously reported that the ClC-2 chloride channel has an important role in regulation of tight junction barrier function during experimental colitis, and the pharmaceutical ClC-2 activator lubiprostone initiates intestinal barrier repair in ischemic-injured intestine. Thus, we hypothesized that pharmaceutical ClC-2 activation would have a protective and therapeutic effect in murine models of colitis, which would be absent in ClC-2 mice. METHODS We administered lubiprostone to wild-type or ClC-2 mice with dextran sulfate sodium (DSS) or 2, 4, 5-trinitrobenzene sulfonic acid-induced colitis. We determined the severity of colitis and assessed intestinal permeability. Selected tight junction proteins were analyzed by Western blotting and immunofluorescence/confocal microscopy, whereas proliferative and differentiated cells were examined with special staining and immunohistochemistry. RESULTS Oral preventive or therapeutic administration of lubiprostone significantly reduced the severity of colitis and reduced intestinal permeability in both DSS and trinitrobenzene sulfonic acid-induced colitis. Preventive treatment with lubiprostone induced significant recovery of the expression and distribution of selected sealing tight junction proteins in mice with DSS-induced colitis. In addition, lubiprostone reduced crypt proliferation and increased the number of differentiated epithelial cells. Alternatively, when lubiprostone was administered to ClC-2 mice, the protective effect against DSS colitis was limited. CONCLUSIONS This study suggests a central role for ClC-2 in restoration of barrier function and tight junction architecture in experimental murine colitis, which can be therapeutically targeted with lubiprostone.
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Jin Y, Blikslager AT. ClC-2 regulation of intestinal barrier function: Translation of basic science to therapeutic target. Tissue Barriers 2015; 3:e1105906. [PMID: 26716076 DOI: 10.1080/21688370.2015.1105906] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Revised: 09/28/2015] [Accepted: 10/01/2015] [Indexed: 02/06/2023] Open
Abstract
The ClC-2 chloride channel is a member of the voltage-gated chloride channel family. ClC-2 is involved in various physiological processes, including fluid transport and secretion, regulation of cell volume and pH, maintaining the membrane potential of the cell, cell-to-cell communication, and tissue homeostasis. Recently, our laboratory has accumulated evidence indicating a critical role of ClC-2 in the regulation of intestinal barrier function by altering inter-epithelial tight junction composition. This review will detail the role of ClC-2 in intestinal barrier function during intestinal disorders, including experimental ischemia/reperfusion injury and dextran sodium sulfate (DSS)-induced inflammatory bowel disease. Details of pharmacological manipulation of ClC-2 via prostone agonists will also be provided in an effort to show the potential therapeutic relevance of ClC-2 regulation, particularly during intestinal barrier disruption.
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Affiliation(s)
- Younggeon Jin
- Department of Clinical Sciences; College of Veterinary Medicine, North Carolina State University ; Raleigh, NC, USA
| | - Anthony T Blikslager
- Department of Clinical Sciences; College of Veterinary Medicine, North Carolina State University ; Raleigh, NC, USA
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Kang SB, Marchelletta RR, Penrose H, Docherty MJ, McCole DF. A comparison of linaclotide and lubiprostone dosing regimens on ion transport responses in human colonic mucosa. Pharmacol Res Perspect 2015; 3:e00128. [PMID: 26038704 PMCID: PMC4448989 DOI: 10.1002/prp2.128] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2015] [Accepted: 01/19/2015] [Indexed: 12/17/2022] Open
Abstract
Linaclotide, a synthetic guanylyl cyclase C (GC-C) agonist, and the prostone analog, Lubiprostone, are approved to manage chronic idiopathic constipation and constipation-predominant irritable bowel syndrome. Lubiprostone also protects intestinal mucosal barrier function in ischemia. GC-C signaling regulates local fluid balance and other components of intestinal mucosal homeostasis including epithelial barrier function. The aim of this study was to compare if select dosing regimens differentially affect linaclotide and lubiprostone modulation of ion transport and barrier properties of normal human colonic mucosa. Normal sigmoid colon biopsies from healthy subjects were mounted in Ussing chambers. Tissues were treated with linaclotide, lubiprostone, or vehicle to determine effects on short-circuit current (Isc). Subsequent Isc responses to the cAMP agonist, forskolin, and the calcium agonist, carbachol, were also measured to assess if either drug caused desensitization. Barrier properties were assessed by measuring transepithelial electrical resistance. Isc responses to linaclotide and lubiprostone were significantly higher than vehicle control when administered bilaterally or to the mucosal side only. Single versus cumulative concentrations of linaclotide showed differences in efficacy while cumulative but not single dosing caused desensitization to forskolin. Lubiprostone reduced forskolin responses under all conditions. Linaclotide and lubiprostone exerted a positive effect on TER that was dependent on the dosing regimen. Linaclotide and lubiprostone increase ion transport responses across normal human colon but linaclotide displays increased sensitivity to the dosing regimen used. These findings may have implications for dosing protocols of these agents in patients with constipation.
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Affiliation(s)
- Sang Bum Kang
- Division of Gastroenterology, Department of Internal Medicine, St. Mary's Hospital, Catholic University of Korea Seoul, Korea ; Division of Gastroenterology, School of Medicine, University of California, San Diego La Jolla, California
| | - Ronald R Marchelletta
- Division of Gastroenterology, School of Medicine, University of California, San Diego La Jolla, California
| | - Harrison Penrose
- Division of Gastroenterology, School of Medicine, University of California, San Diego La Jolla, California
| | - Michael J Docherty
- Division of Gastroenterology, School of Medicine, University of California, San Diego La Jolla, California
| | - Declan F McCole
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside Riverside, California
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Rossi M, Merello M, Perez-Lloret S. Management of constipation in Parkinson's disease. Expert Opin Pharmacother 2014; 16:547-57. [PMID: 25539892 DOI: 10.1517/14656566.2015.997211] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
INTRODUCTION Constipation is a frequent non-motor feature of Parkinson's disease (PD). It is the most common gastrointestinal symptom of the disease and it can precede motor symptoms by as much as 20 years. Constipation can produce discomfort and affect activities of daily living, productivity and quality of life, thus warranting early diagnosis and treatment. AREAS COVERED In this review, the safety and efficacy of traditional and novel strategies for constipation management will be discussed. A treatment algorithm for constipation in PD will be presented. EXPERT OPINION Polyethylene glycol and lubiprostone are first-line compounds recommended by evidence-based medicine guidelines for the treatment of constipation due to slow colonic transit in PD. Management of constipation secondary to defecatory dysfunction due to pelvic floor dyssynergia can be done by levodopa or apomorphine injections, botulinum toxin type A injection into the puborectalis muscle, and nonpharmacological interventions, like biofeedback therapy or functional magnetic stimulation, which showed some benefit in PD patients with constipation, but in general more extensive studies are warranted.
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Affiliation(s)
- Malco Rossi
- Raul Carrea Institute for Neurological Research (FLENI), Neuroscience Department, Movement Disorders Section , Buenos Aires , Argentina
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Cuppoletti J, Chakrabarti J, Tewari KP, Malinowska DH. Differentiation between human ClC-2 and CFTR Cl− channels with pharmacological agents. Am J Physiol Cell Physiol 2014; 307:C479-92. [DOI: 10.1152/ajpcell.00077.2014] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
It has been difficult to separate/identify the roles of ClC-2 and CFTR in Cl− transport studies. Using pharmacological agents, we aimed to differentiate functionally between ClC-2 and CFTR Cl− channel currents. Effects of CFTR inhibitor 172 (CFTRinh172), N-(4-methylphenylsulfonyl)- N′-(4-trifluoromethylphenyl)urea (DASU-02), and methadone were examined by whole cell patch clamp on Cl− currents in recombinant human ClC-2/human embryonic kidney 293 (ClC-2/HEK293) cells stably transformed with Epstein-Barr nuclear antigen 1 (hClC-2/293EBNA) and human CFTR/HEK293 (hCFTR/HEK293) cells and by short-circuit current ( Isc) measurements in T84 cells. Lubiprostone and forskolin-IBMX were used as activators. CFTRinh172 inhibited forskolin-IBMX-stimulated recombinant human CFTR (hCFTR) and lubiprostone-stimulated recombinant human ClC-2 (hClC-2) Cl− currents in a concentration-dependent manner equipotently. DASU-02 inhibited forskolin-IBMX-stimulated Cl− currents in hCFTR/HEK293 cells, but not lubiprostone-stimulated Cl− currents in hClC-2/293EBNA cells. In T84 cells with basolateral nystatin or 1-ethyl-2-benzimidazolinone (1-EBIO), lubiprostone-stimulated and forskolin-IBMX-cyclosporin A (FICA)-stimulated Isc components were observed. CFTRinh172 inhibited major portions of both components. DASU-02 had no effect on lubiprostone-stimulated Isc but partially inhibited FICA-stimulated Isc. T84 cells in which ClC-2 or CFTR was knocked down using siRNAs were constructed. T84 ClC-2 knockdown cells did not respond to lubiprostone but did respond to forskolin-IBMX in a methadone-insensitive, DASU-02-sensitive manner, indicating CFTR function. T84 CFTR knockdown cells responded separately to lubiprostone and forskolin-IBMX in a methadone-sensitive and DASU-02-insensitive manner, indicating ClC-2 function. Low lubiprostone concentrations activated ClC-2, but not CFTR, and both channels were activated by forskolin-IBMX but have different inhibitor sensitivities. Methadone, but not DASU-02, inhibited ClC-2. DASU-02, but not methadone, inhibited CFTR. In T84 cells, both ClC-2 and CFTR are present and likely play roles in Cl− secretion.
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Affiliation(s)
- John Cuppoletti
- Department of Molecular and Cellular Physiology, University of Cincinnati College of Medicine, Cincinnati, Ohio
| | - Jayati Chakrabarti
- Department of Molecular and Cellular Physiology, University of Cincinnati College of Medicine, Cincinnati, Ohio
| | - Kirti P. Tewari
- Department of Molecular and Cellular Physiology, University of Cincinnati College of Medicine, Cincinnati, Ohio
| | - Danuta H. Malinowska
- Department of Molecular and Cellular Physiology, University of Cincinnati College of Medicine, Cincinnati, Ohio
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Jiao HY, Kim DH, Ki JS, Ryu KH, Choi S, Jun JY. Effects of lubiprostone on pacemaker activity of interstitial cells of cajal from the mouse colon. THE KOREAN JOURNAL OF PHYSIOLOGY & PHARMACOLOGY : OFFICIAL JOURNAL OF THE KOREAN PHYSIOLOGICAL SOCIETY AND THE KOREAN SOCIETY OF PHARMACOLOGY 2014; 18:341-6. [PMID: 25177167 PMCID: PMC4146637 DOI: 10.4196/kjpp.2014.18.4.341] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/01/2014] [Revised: 07/09/2014] [Accepted: 07/09/2014] [Indexed: 12/13/2022]
Abstract
Lubiprostone is a chloride (Cl-) channel activator derived from prostaglandin E1 and used for managing constipation. In addition, lubiprostone affects the activity of gastrointestinal smooth muscles. Interstitial cells of Cajal (ICCs) are pacemaker cells that generate slow-wave activity in smooth muscles. We studied the effects of lubiprostone on the pacemaker potentials of colonic ICCs. We used the whole-cell patch-clamp technique to determine the pacemaker activity in cultured colonic ICCs obtained from mice. Lubiprostone hyperpolarized the membrane and inhibited the generation of pacemaker potentials. Prostanoid EP1, EP2, EP3, and EP4 antagonists (SC-19220, PF-04418948, 6-methoxypyridine-2-boronc acid N-phenyldiethanolamine ester, and GW627368, respectively) did not block the response to lubiprostone. L-NG-nitroarginine methyl ester (L-NAME, an inhibitor of nitric oxide synthase) and 1H-[1,2,4]oxadiazolo[4,3,-a]quinoxalin-1-one (ODQ, an inhibitor of guanylate cyclase) did not block the response to lubiprostone. In addition, tetraethylammonium (TEA, a voltage-dependent potassium [K+] channel blocker) and apamin (a calcium [Ca2+]-dependent K+ channel blocker) did not block the response to lubiprostone. However, glibenclamide (an ATP-sensitive K+ channel blocker) blocked the response to lubiprostone. Similar to lubiprostone, pinacidil (an opener of ATP-sensitive K+ channel) hyperpolarized the membrane and inhibited the generation of pacemaker potentials, and these effects were inhibited by glibenclamide. These results suggest that lubiprostone can modulate the pacemaker potentials of colonic ICCs via activation of ATP-sensitive K+ channel through a prostanoid EP receptor-independent mechanism.
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Affiliation(s)
- Han-Yi Jiao
- Department of Physiology, College of Medicine, Chosun University, Gwangju 501-759, Korea
| | - Dong Hyun Kim
- Department of Radiology, College of Medicine, Chosun University, Gwangju 501-759, Korea
| | - Jung Suk Ki
- Department of Physiology, College of Medicine, Chosun University, Gwangju 501-759, Korea
| | - Kwon Ho Ryu
- Department of Physiology, College of Medicine, Chosun University, Gwangju 501-759, Korea
| | - Seok Choi
- Department of Physiology, College of Medicine, Chosun University, Gwangju 501-759, Korea
| | - Jae Yeoul Jun
- Department of Physiology, College of Medicine, Chosun University, Gwangju 501-759, Korea
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Sobczak M, Sałaga M, Storr MA, Fichna J. Physiology, signaling, and pharmacology of opioid receptors and their ligands in the gastrointestinal tract: current concepts and future perspectives. J Gastroenterol 2014; 49:24-45. [PMID: 23397116 PMCID: PMC3895212 DOI: 10.1007/s00535-013-0753-x] [Citation(s) in RCA: 125] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/28/2012] [Accepted: 01/10/2013] [Indexed: 02/04/2023]
Abstract
Opioid receptors are widely distributed in the human body and are crucially involved in numerous physiological processes. These include pain signaling in the central and the peripheral nervous system, reproduction, growth, respiration, and immunological response. Opioid receptors additionally play a major role in the gastrointestinal (GI) tract in physiological and pathophysiological conditions. This review discusses the physiology and pharmacology of the opioid system in the GI tract. We additionally focus on GI disorders and malfunctions, where pathophysiology involves the endogenous opioid system, such as opioid-induced bowel dysfunction, opioid-induced constipation or abdominal pain. Based on recent reports in the field of pharmacology and medicinal chemistry, we will also discuss the opportunities of targeting the opioid system, suggesting future treatment options for functional disorders and inflammatory states of the GI tract.
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Affiliation(s)
- Marta Sobczak
- Department of Biomolecular Chemistry, Faculty of Medicine, Medical University of Lodz, Mazowiecka 6/8, 92-215 Lodz, Poland
| | - Maciej Sałaga
- Department of Biomolecular Chemistry, Faculty of Medicine, Medical University of Lodz, Mazowiecka 6/8, 92-215 Lodz, Poland
| | - Martin A. Storr
- Division of Gastroenterology, Department of Medicine, Ludwig Maximilians University of Munich, Munich, Germany
| | - Jakub Fichna
- Department of Biomolecular Chemistry, Faculty of Medicine, Medical University of Lodz, Mazowiecka 6/8, 92-215 Lodz, Poland
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Methadone but not morphine inhibits lubiprostone-stimulated Cl- currents in T84 intestinal cells and recombinant human ClC-2, but not CFTR Cl- currents. Cell Biochem Biophys 2013; 66:53-63. [PMID: 22918821 PMCID: PMC3627040 DOI: 10.1007/s12013-012-9406-6] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
In clinical trials, methadone, but not morphine, appeared to prevent beneficial effects of lubiprostone, a ClC-2 Cl− channel activator, on opioid-induced constipation. Effects of methadone and morphine on lubiprostone-stimulated Cl− currents were measured by short circuit current (Isc) across T84 cells. Whole cell patch clamp of human ClC-2 (hClC-2) stably expressed in HEK293 cells and in a high expression cell line (HEK293EBNA) as well as human CFTR (hCFTR) stably expressed in HEK293 cells was used to study methadone and morphine effects on recombinant hClC-2 and hCFTR Cl− currents. Methadone but not morphine inhibited lubiprostone-stimulated Isc in T84 cells with half-maximal inhibition at 100 nM. Naloxone did not affect lubiprostone stimulation or methadone inhibition of Isc. Lubiprostone-stimulated Cl− currents in hClC-2/HEK293 cells, but not forskolin/IBMX-stimulated Cl− currents in hCFTR/HEK293 cells, were inhibited by methadone, but not morphine. HEK293EBNA cells expressing hClC-2 showed time-dependent, voltage-activated, CdCl2-inhibited Cl− currents in the absence (control) and the presence of lubiprostone. Methadone, but not morphine, inhibited control and lubiprostone-stimulated hClC-2 Cl− currents with half-maximal inhibition at 100 and 200–230 nM, respectively. Forskolin/IBMX-stimulated hClC-2 Cl− currents were also inhibited by methadone. Myristoylated protein kinase inhibitor (a specific PKA inhibitor) inhibited forskolin/IBMX- but not lubiprostone-stimulated hClC-2 Cl− currents. Methadone caused greater inhibition of lubiprostone-stimulated currents added before patching (66.1 %) compared with after patching (28.7 %). Methadone caused inhibition of lubiprostone-stimulated Cl− currents in T84 cells and control; lubiprostone- and forskolin/IBMX-stimulated recombinant hClC-2 Cl− currents may be the basis for reduced efficacy of lubiprostone in methadone-treated patients.
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Stauber T, Weinert S, Jentsch TJ. Cell biology and physiology of CLC chloride channels and transporters. Compr Physiol 2013; 2:1701-44. [PMID: 23723021 DOI: 10.1002/cphy.c110038] [Citation(s) in RCA: 112] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Proteins of the CLC gene family assemble to homo- or sometimes heterodimers and either function as Cl(-) channels or as Cl(-)/H(+)-exchangers. CLC proteins are present in all phyla. Detailed structural information is available from crystal structures of bacterial and algal CLCs. Mammals express nine CLC genes, four of which encode Cl(-) channels and five 2Cl(-)/H(+)-exchangers. Two accessory β-subunits are known: (1) barttin and (2) Ostm1. ClC-Ka and ClC-Kb Cl(-) channels need barttin, whereas Ostm1 is required for the function of the lysosomal ClC-7 2Cl(-)/H(+)-exchanger. ClC-1, -2, -Ka and -Kb Cl(-) channels reside in the plasma membrane and function in the control of electrical excitability of muscles or neurons, in extra- and intracellular ion homeostasis, and in transepithelial transport. The mainly endosomal/lysosomal Cl(-)/H(+)-exchangers ClC-3 to ClC-7 may facilitate vesicular acidification by shunting currents of proton pumps and increase vesicular Cl(-) concentration. ClC-3 is also present on synaptic vesicles, whereas ClC-4 and -5 can reach the plasma membrane to some extent. ClC-7/Ostm1 is coinserted with the vesicular H(+)-ATPase into the acid-secreting ruffled border membrane of osteoclasts. Mice or humans lacking ClC-7 or Ostm1 display osteopetrosis and lysosomal storage disease. Disruption of the endosomal ClC-5 Cl(-)/H(+)-exchanger leads to proteinuria and Dent's disease. Mouse models in which ClC-5 or ClC-7 is converted to uncoupled Cl(-) conductors suggest an important role of vesicular Cl(-) accumulation in these pathologies. The important functions of CLC Cl(-) channels were also revealed by human diseases and mouse models, with phenotypes including myotonia, renal loss of salt and water, deafness, blindness, leukodystrophy, and male infertility.
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Affiliation(s)
- Tobias Stauber
- Leibniz-Institut für Molekulare Pharmakologie FMP and Max-Delbrück-Centrum für Molekulare Medizin MDC, Berlin, Germany
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Ao M, Sarathy J, Domingue J, Alrefai WA, Rao MC. Chenodeoxycholic acid stimulates Cl(-) secretion via cAMP signaling and increases cystic fibrosis transmembrane conductance regulator phosphorylation in T84 cells. Am J Physiol Cell Physiol 2013; 305:C447-56. [PMID: 23761628 DOI: 10.1152/ajpcell.00416.2012] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
High levels of chenodeoxycholic acid (CDCA) and deoxycholic acid stimulate Cl(-) secretion in mammalian colonic epithelia. While different second messengers have been implicated in this action, the specific signaling pathway has not been fully delineated. Using human colon carcinoma T84 cells, we elucidated this cascade assessing Cl(-) transport by measuring I(-) efflux and short-circuit current (Isc). CDCA (500 μM) rapidly increases I(-) efflux, and we confirmed by Isc that it elicits a larger response when added to the basolateral vs. apical surface. However, preincubation with cytokines increases the monolayer responsiveness to apical addition by 55%. Nystatin permeabilization studies demonstrate that CDCA stimulates an eletrogenic apical Cl(-) but not a basolateral K(+) current. Furthermore, CDCA-induced Isc was inhibited (≥67%) by bumetanide, BaCl2, and the cystic fibrosis transmembrane conductance regulator (CFTR) inhibitor CFTRinh-172. CDCA-stimulated Isc was decreased 43% by the adenylate cyclase inhibitor MDL12330A and CDCA increases intracellular cAMP concentration. The protein kinase A inhibitor H89 and the microtubule disrupting agent nocodazole, respectively, cause 94 and 47% reductions in CDCA-stimulated Isc. Immunoprecipitation with CFTR antibodies, followed by sequential immunoblotting with Pan-phospho and CFTR antibodies, shows that CDCA increases CFTR phosphorylation by approximately twofold. The rapidity and side specificity of the response to CDCA imply a membrane-mediated process. While CDCA effects are not blocked by the muscarinic receptor antagonist atropine, T84 cells possess transcript and protein for the bile acid G protein-coupled receptor TGR5. These results demonstrate for the first time that CDCA activates CFTR via a cAMP-PKA pathway involving microtubules and imply that this occurs via a basolateral membrane receptor.
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Affiliation(s)
- Mei Ao
- Department of Physiology and Biophysics, University of Illinois, Chicago, Illinois
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Amin R, Sharma S, Ratakonda S, Hassan HA. Extracellular nucleotides inhibit oxalate transport by human intestinal Caco-2-BBe cells through PKC-δ activation. Am J Physiol Cell Physiol 2013; 305:C78-89. [PMID: 23596171 DOI: 10.1152/ajpcell.00339.2012] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Nephrolithiasis remains a major health problem in Western countries. Seventy to 80% of kidney stones are composed of calcium oxalate, and small changes in urinary oxalate affect risk of kidney stone formation. Intestinal oxalate secretion mediated by the anion exchanger SLC26A6 plays an essential role in preventing hyperoxaluria and calcium oxalate nephrolithiasis, indicating that understanding the mechanisms regulating intestinal oxalate transport is critical for management of hyperoxaluria. Purinergic signaling modulates several intestinal processes through pathways including PKC activation, which we previously found to inhibit Slc26a6 activity in mouse duodenal tissue. We therefore examined whether purinergic stimulation with ATP and UTP affects oxalate transport by human intestinal Caco-2-BBe (C2) cells. We measured [¹⁴C]oxalate uptake in the presence of an outward Cl⁻ gradient as an assay of Cl⁻/oxalate exchange activity, ≥50% of which is mediated by SLC26A6. We found that ATP and UTP significantly inhibited oxalate transport by C2 cells, an effect blocked by the PKC inhibitor Gö-6983. Utilizing pharmacological agonists and antagonists, as well as PKC-δ knockdown studies, we observed that ATP inhibits oxalate transport through the P2Y₂ receptor, PLC, and PKC-δ. Biotinylation studies showed that ATP inhibits oxalate transport by lowering SLC26A6 surface expression. These findings are of potential relevance to pathophysiology of inflammatory bowel disease-associated hyperoxaluria, where supraphysiological levels of ATP/UTP are expected and overexpression of the P2Y₂ receptor has been reported. We conclude that ATP and UTP inhibit oxalate transport by lowering SLC26A6 surface expression in C2 cells through signaling pathways including the P2Y₂ purinergic receptor, PLC, and PKC-δ.
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Affiliation(s)
- Ruhul Amin
- Department of Medicine, University of Chicago, Chicago, IL 60637, USA
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Musch MW, Wang Y, Claud EC, Chang EB. Lubiprostone decreases mouse colonic inner mucus layer thickness and alters intestinal microbiota. Dig Dis Sci 2013; 58:668-77. [PMID: 23329012 PMCID: PMC3618493 DOI: 10.1007/s10620-012-2509-5] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/01/2011] [Accepted: 12/01/2012] [Indexed: 01/02/2023]
Abstract
BACKGROUND Lubiprostone has been used to treat constipation through its effects to stimulate Cl(-) secretion, resulting in water and electrolyte secretion. AIM Potential associated changes in intestinal mucus and the colonizing bacteria (microbiome) have not been studied. As mucus obstructions may play a role in cystic fibrosis, the hypothesis that lubiprostone alters intestinal mucus and the microbiome was investigated. METHODS Ion transport studies were performed ex vivo. For mucus and microbiome studies, mice were gavaged daily with lubiprostone or vehicle. Mucin from intestinal sections was analyzed in Carnoy's fixed tissues stained with Alcian blue. Microbiome composition was analyzed by 16S rRNA gene-based sequencing. RESULTS Lubiprostone stimulated short circuit current in all mouse intestinal segments after both serosal and mucosal additions, albeit at lower concentrations in the latter. Current was Cl-dependent and blocked by mucosal diphenylcarboxylic acid, serosal bumetanide, and serosal Ba(++). The CFTR inhibitor CFTRinh172 had a marginal effect. Mucus near epithelial cells (inner layer mucus) was not present in the small intestine of any mice. Proximal colon inner mucus layer was thicker in ∆F/∆F compared with +/∆F and +/+ mice. Lubiprostone decreased inner mucus layer thickness in both proximal and distal colon of all mice. Furthermore, lubiprostone altered the intestinal microbiome by increasing abundance of Lactobacillus and Alistipes. CONCLUSIONS Lubiprostone activates non-CFTR Cl(-) secretion and alters the colonic inner mucus layer, which is associated with changes in the composition of the enteric microbiome.
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Affiliation(s)
- Mark W Musch
- Division of Biological Sciences, Department of Medicine, The University of Chicago, 900 E. 57th St., Chicago, IL 60637, USA
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Schiffhauer ES, Vij N, Kovbasnjuk O, Kang PW, Walker D, Lee S, Zeitlin PL. Dual activation of CFTR and CLCN2 by lubiprostone in murine nasal epithelia. Am J Physiol Lung Cell Mol Physiol 2013; 304:L324-31. [PMID: 23316067 DOI: 10.1152/ajplung.00277.2012] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Multiple sodium and chloride channels on the apical surface of nasal epithelial cells contribute to periciliary fluid homeostasis, a function that is disrupted in patients with cystic fibrosis (CF). Among these channels is the chloride channel CLCN2, which has been studied as a potential alternative chloride efflux pathway in the absence of CFTR. The object of the present study was to use the nasal potential difference test (NPD) to quantify CLCN2 function in an epithelial-directed TetOn CLCN2 transgenic mouse model (TGN-K18rtTA-hCLCN2) by using the putative CLCN2 pharmacological agonist lubiprostone and peptide inhibitor GaTx2. Lubiprostone significantly increased chloride transport in the CLCN2-overexpressing mice following activation of the transgene by doxycycline. This response to lubiprostone was significantly inhibited by GaTx2 after CLCN2 activation in TGN-CLCN2 mice. Cftr(-/-) and Clc2(-/-) mice showed hyperpolarization indicative of chloride efflux in response to lubiprostone, which was fully inhibited by GaTx2 and CFTR inhibitor 172 + GlyH-101, respectively. Our study reveals lubiprostone as a pharmacological activator of both CFTR and CLCN2. Overexpression and activation of CLCN2 leads to improved mouse NPD readings, suggesting it is available as an alternative pathway for epithelial chloride secretion in murine airways. The utilization of CLCN2 as an alternative chloride efflux channel could provide clinical benefit to patients with CF, especially if the pharmacological activator is administered as an aerosol.
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Affiliation(s)
- Eric S Schiffhauer
- Department of Pediatrics, The Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
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BHARUCHA ADILE, PEMBERTON JOHNH, LOCKE GRICHARD. American Gastroenterological Association technical review on constipation. Gastroenterology 2013; 144:218-38. [PMID: 23261065 PMCID: PMC3531555 DOI: 10.1053/j.gastro.2012.10.028] [Citation(s) in RCA: 505] [Impact Index Per Article: 45.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- ADIL E. BHARUCHA
- Division of Gastroenterology and Hepatology Mayo Clinic and Mayo Medical School Rochester, Minnesota
| | - JOHN H. PEMBERTON
- Division of Colon and Rectal Surgery Mayo Clinic and Mayo Medical School Rochester, Minnesota
| | - G. RICHARD LOCKE
- Division of Gastroenterology and Hepatology Mayo Clinic and Mayo Medical School Rochester, Minnesota
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Lubiprostone targets prostanoid signaling and promotes ion transporter trafficking, mucus exocytosis, and contractility. Dig Dis Sci 2012; 57:2826-45. [PMID: 22923315 PMCID: PMC3482986 DOI: 10.1007/s10620-012-2352-8] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2012] [Accepted: 07/28/2012] [Indexed: 12/12/2022]
Abstract
BACKGROUND AND AIM Lubiprostone is a chloride channel activator in clinical use for the treatment of chronic constipation, but the mechanisms of action of the drug are poorly understood. The aim of this study was to determine whether lubiprostone exerts secretory effects in the intestine by membrane trafficking of ion transporters and associated machinery. METHODS Immunolabeling and quantitative fluorescence intensity were used to examine lubiprostone-induced trafficking of the cystic fibrosis transmembrane conductance regulator (CFTR), sodium/potassium-coupled chloride co-transporter 1 (NKCC1), electrogenic sodium/bicarbonate co-transporter 1 (NBCe1), down-regulated in adenoma (DRA), putative anion transporter 1 (PAT1), sodium/proton exchanger 3 (NHE3), Ca(2+) activated chloride channel 2 (ClC-2) serotonin and its transporter SERT, E prostanoid receptors EP4 and EP1, sodium/potassium ATPase (Na-K-ATPase) and protein kinase A (PKA). The effects of lubiprostone on mucus exocytosis in rat intestine and human rectosigmoid explants were also examined. RESULTS Lubiprostone induced contraction of villi and proximal colonic plicae and membrane trafficking of transporters that was more pronounced in villus/surface cells compared to the crypt. Membrane trafficking was determined by: (1) increased membrane labeling for CFTR, PAT1, NKCC1, and NBCe1 and decreased membrane labeling for NHE3, DRA and ClC-2; (2) increased serotonin, SERT, EP4, EP1 and PKA labeling in enterochromaffin cells; (3) increased SERT, EP4, EP1, PKA and Na-K-ATPase in enterocytes; and (4) increased mucus exocytosis in goblet cells. CONCLUSION These data suggest that lubiprostone can target serotonergic, EP4/PKA and EP1 signaling in surface/villus regions; stimulate membrane trafficking of CFTR/NBCe1/NKCC1 in villus epithelia and PAT1/NBCe1/NKCC1 in colonic surface epithelia; suppress NHE3/DRA trafficking and fluid absorption; and enhance mucus-mobilization and mucosal contractility.
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Akiba Y, Kaunitz JD. May the truth be with you: lubiprostone as EP receptor agonist/ClC-2 internalizing "inhibitor". Dig Dis Sci 2012; 57:2740-2. [PMID: 23001408 DOI: 10.1007/s10620-012-2410-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/09/2022]
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Norimatsu Y, Moran AR, MacDonald KD. Lubiprostone activates CFTR, but not ClC-2, via the prostaglandin receptor (EP(4)). Biochem Biophys Res Commun 2012; 426:374-9. [PMID: 22960173 DOI: 10.1016/j.bbrc.2012.08.097] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2012] [Accepted: 08/21/2012] [Indexed: 11/19/2022]
Abstract
The goal of this study was to determine the mechanism of lubiprostone activation of epithelial chloride transport. Lubiprostone is a bicyclic fatty acid approved for the treatment of constipation [1]. There is uncertainty, however, as to how lubiprostone increases epithelial chloride transport. Direct stimulation of ClC-2 and CFTR chloride channels as well as stimulation of these channels via the EP(4) receptor has been described [2-5]. To better define this mechanism, two-electrode voltage clamp was used to assay Xenopus oocytes expressing ClC-2, with or without co-expression of the EP(4) receptor or β adrenergic receptor (βAR), for changes in conductance elicited by lubiprostone. Oocytes co-expressing CFTR and either βAR or the EP(4) receptor were also studied. In oocytes co-expressing ClC-2 and βAR conductance was stimulated by hyperpolarization and acidic pH (pH = 6), but there was no response to the β adrenergic agonist, isoproterenol. Oocytes expressing ClC-2 only or co-expressing ClC-2 and EP(4) did not respond to the presence of 0.1, 1, or 10 μM lubiprostone in the superperfusate. Oocytes co-expressing CFTR and βAR did not respond to hyperpolarization, acidic pH, or 1 μM lubiprostone. However, conductance was elevated by isoproterenol and inhibited by CFTR(inh)172. Co-expression of CFTR and EP(4) resulted in lubiprostone-stimulated conductance, which was also sensitive to CFTR(inh)172. The EC(50) for lubiprostone mediated CFTR activation was ~10 nM. These results demonstrate no direct action of lubiprostone on either ClC-2 or CFTR channels expressed in oocytes. However, the results confirm that CFTR can be activated by lubiprostone via the EP(4) receptor in oocytes.
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Affiliation(s)
- Yohei Norimatsu
- Department of Physiology - Pharmacology, Oregon Health and Science University, OR 97239, USA
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Muanprasat C, Sirianant L, Soodvilai S, Chokchaisiri R, Suksamrarn A, Chatsudthipong V. Novel Action of the Chalcone Isoliquiritigenin as a Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) Inhibitor: Potential Therapy for Cholera and Polycystic Kidney Disease. J Pharmacol Sci 2012; 118:82-91. [DOI: 10.1254/jphs.11153fp] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2011] [Accepted: 11/10/2011] [Indexed: 10/14/2022] Open
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Hassan HA, Cheng M, Aronson PS. Cholinergic signaling inhibits oxalate transport by human intestinal T84 cells. Am J Physiol Cell Physiol 2011; 302:C46-58. [PMID: 21956166 DOI: 10.1152/ajpcell.00075.2011] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Urolithiasis remains a very common disease in Western countries. Seventy to eighty percent of kidney stones are composed of calcium oxalate, and minor changes in urinary oxalate affect stone risk. Intestinal oxalate secretion mediated by anion exchanger SLC26A6 plays a major constitutive role in limiting net absorption of ingested oxalate, thereby preventing hyperoxaluria and calcium oxalate urolithiasis. Using the relatively selective PKC-δ inhibitor rottlerin, we had previously found that PKC-δ activation inhibits Slc26a6 activity in mouse duodenal tissue. To identify a model system to study physiologic agonists upstream of PKC-δ, we characterized the human intestinal cell line T84. Knockdown studies demonstrated that endogenous SLC26A6 mediates most of the oxalate transport by T84 cells. Cholinergic stimulation with carbachol modulates intestinal ion transport through signaling pathways including PKC activation. We therefore examined whether carbachol affects oxalate transport in T84 cells. We found that carbachol significantly inhibited oxalate transport by T84 cells, an effect blocked by rottlerin. Carbachol also led to significant translocation of PKC-δ from the cytosol to the membrane of T84 cells. Using pharmacological inhibitors, we observed that carbachol inhibits oxalate transport through the M(3) muscarinic receptor and phospholipase C. Utilizing the Src inhibitor PP2 and phosphorylation studies, we found that the observed regulation downstream of PKC-δ is partially mediated by c-Src. Biotinylation studies revealed that carbachol inhibits oxalate transport by reducing SLC26A6 surface expression. We conclude that carbachol negatively regulates oxalate transport by reducing SLC26A6 surface expression in T84 cells through signaling pathways including the M(3) muscarinic receptor, phospholipase C, PKC-δ, and c-Src.
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Affiliation(s)
- Hatim A Hassan
- Section of Nephrology, Dept. of Medicine, The Univ. of Chicago, 5841 S. Maryland Ave., MC5100, Chicago, IL 60637, USA.
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O'Brien CE, Anderson PJ, Stowe CD. Lubiprostone for Constipation in Adults with Cystic Fibrosis: A Pilot Study. Ann Pharmacother 2011; 45:1061-6. [DOI: 10.1345/aph.1q219] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Affiliation(s)
- Catherine E O'Brien
- Department of Pharmacy Practice, College of Pharmacy, University of Arkansas for Medical Sciences, Little Rock, AR
| | - Paula J Anderson
- Department of Internal Medicine, Division of Pulmonary and Critical Care Medicine, College of Medicine, University of Arkansas for Medical Sciences
| | - Cindy D Stowe
- Department of Pharmacy Practice, College of Pharmacy, University of Arkansas for Medical Sciences
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Vazquez Roque M, Camilleri M. Linaclotide, a synthetic guanylate cyclase C agonist, for the treatment of functional gastrointestinal disorders associated with constipation. Expert Rev Gastroenterol Hepatol 2011; 5:301-10. [PMID: 21651347 DOI: 10.1586/egh.11.30] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Chronic constipation (CC) and irritable bowel syndrome with constipation (IBS-C) are two functional gastrointestinal disorders that are associated with constipation. CC and IBS-C affect approximately 20% of the general population including the elderly, impairing quality of life. Patients not responding to over-the-counter treatments require effective and safe long-term therapies. Some treatments introduced in the last decade have been associated with side effects that led to withdrawal from the US market (e.g., tegaserod) or intolerance to treatment (e.g., nausea in patients treated with lubiprostone). Linaclotide is a novel drug, with a unique mechanism of action, low bioavailability and local action in the intestinal epithelial cells. It is currently being developed for patients with CC and IBS-C. From animal studies to human pharmacodynamic Phase Ib trials, and a comprehensive program of Phase IIb and III trials in health and disease, linaclotide demonstrates long-term efficacy and safety in CC and IBS-C.
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Affiliation(s)
- Maria Vazquez Roque
- Clinical Enteric Neuroscience Translational and Epidemiological Research, Mayo Clinic, Rochester, MN, USA
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