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Kota P. Sustained inhibition of ENaC in CF: Potential RNA-based therapies for mutation-agnostic treatment. Curr Opin Pharmacol 2022; 64:102209. [PMID: 35483215 DOI: 10.1016/j.coph.2022.102209] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Revised: 02/26/2022] [Accepted: 03/02/2022] [Indexed: 12/17/2022]
Abstract
Disruption of the equilibrium between ion secretion and absorption processes by the airway epithelium is central to many muco-obstructive lung diseases including cystic fibrosis (CF). Besides correction of defective folding and function of CFTR, inhibition of amiloride-sensitive epithelia sodium channels (ENaC) has emerged as a bona fide therapeutic strategy to improve mucociliary clearance in patients with CF. The short half-life of amiloride-based ENaC blockers and hyperosmotic therapies have led to the development of novel RNA-based interventions for targeted and sustained reduction of ENaC expression and function in preclinical models of CF. This review summarizes the recent advances in RNA therapeutics targeting ENaC for mutation-agnostic treatment of CF.
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Affiliation(s)
- Pradeep Kota
- Cystic Fibrosis Research and Treatment Center, University of North Carolina at Chapel Hill, NC 27599, USA.
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Hiramatsu A, Izumi Y, Eguchi K, Matsuo N, Deng Q, Inoue H, Nakayama Y, Nonoguchi H, Aramburu J, López-Rodríguez C, Kakizoe Y, Adachi M, Kuwabara T, Kim-Mitsuyama S, Mukoyama M. Salt-Sensitive Hypertension of the Renal Tubular Cell-Specific NFAT5 (Nuclear Factor of Activated T-Cells 5) Knockout Mice. Hypertension 2021; 78:1335-1346. [PMID: 34601973 DOI: 10.1161/hypertensionaha.121.17435] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
[Figure: see text].
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Affiliation(s)
- Akiko Hiramatsu
- Department of Nephrology (A.H., Y.I., K.E., N.M., Q.D., H.I., Y.N., Y.K., M.A., T.K., M.M.), Kumamoto University Graduate School of Medical Sciences, Japan
| | - Yuichiro Izumi
- Department of Nephrology (A.H., Y.I., K.E., N.M., Q.D., H.I., Y.N., Y.K., M.A., T.K., M.M.), Kumamoto University Graduate School of Medical Sciences, Japan
| | - Koji Eguchi
- Department of Nephrology (A.H., Y.I., K.E., N.M., Q.D., H.I., Y.N., Y.K., M.A., T.K., M.M.), Kumamoto University Graduate School of Medical Sciences, Japan
| | - Naomi Matsuo
- Department of Nephrology (A.H., Y.I., K.E., N.M., Q.D., H.I., Y.N., Y.K., M.A., T.K., M.M.), Kumamoto University Graduate School of Medical Sciences, Japan
| | - Qinyuan Deng
- Department of Nephrology (A.H., Y.I., K.E., N.M., Q.D., H.I., Y.N., Y.K., M.A., T.K., M.M.), Kumamoto University Graduate School of Medical Sciences, Japan
| | - Hideki Inoue
- Department of Nephrology (A.H., Y.I., K.E., N.M., Q.D., H.I., Y.N., Y.K., M.A., T.K., M.M.), Kumamoto University Graduate School of Medical Sciences, Japan
| | - Yushi Nakayama
- Department of Nephrology (A.H., Y.I., K.E., N.M., Q.D., H.I., Y.N., Y.K., M.A., T.K., M.M.), Kumamoto University Graduate School of Medical Sciences, Japan
| | - Hiroshi Nonoguchi
- Division of Internal Medicine, Kitasato University Medical Center, Kitamoto, Saitama, Japan (H.N.)
| | - Jose Aramburu
- Immunology Unit, Department of Experimental and Health Sciences, Universitat Pompeu Fabra, and Barcelona Biomedical Research Park, Spain (J.A., C.L.-R.)
| | - Cristina López-Rodríguez
- Immunology Unit, Department of Experimental and Health Sciences, Universitat Pompeu Fabra, and Barcelona Biomedical Research Park, Spain (J.A., C.L.-R.)
| | - Yutaka Kakizoe
- Department of Nephrology (A.H., Y.I., K.E., N.M., Q.D., H.I., Y.N., Y.K., M.A., T.K., M.M.), Kumamoto University Graduate School of Medical Sciences, Japan
| | - Masataka Adachi
- Department of Nephrology (A.H., Y.I., K.E., N.M., Q.D., H.I., Y.N., Y.K., M.A., T.K., M.M.), Kumamoto University Graduate School of Medical Sciences, Japan
| | - Takashige Kuwabara
- Department of Nephrology (A.H., Y.I., K.E., N.M., Q.D., H.I., Y.N., Y.K., M.A., T.K., M.M.), Kumamoto University Graduate School of Medical Sciences, Japan
| | - Shokei Kim-Mitsuyama
- Department of Pharmacology and Molecular Therapeutics (S.K.-M.), Kumamoto University Graduate School of Medical Sciences, Japan
| | - Masashi Mukoyama
- Department of Nephrology (A.H., Y.I., K.E., N.M., Q.D., H.I., Y.N., Y.K., M.A., T.K., M.M.), Kumamoto University Graduate School of Medical Sciences, Japan
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Giorgetti M, Klymiuk N, Bähr A, Hemmerling M, Jinton L, Tarran R, Malmgren A, Åstrand A, Hansson GC, Ermund A. New generation ENaC inhibitors detach cystic fibrosis airway mucus bundles via sodium/hydrogen exchanger inhibition. Eur J Pharmacol 2021; 904:174123. [PMID: 33974881 PMCID: PMC8477379 DOI: 10.1016/j.ejphar.2021.174123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Revised: 04/19/2021] [Accepted: 04/23/2021] [Indexed: 11/18/2022]
Abstract
Cystic fibrosis (CF) is a recessive inherited disease caused by mutations affecting anion transport by the epithelial ion channel cystic fibrosis transmembrane conductance regulator (CFTR). The disease is characterized by mucus accumulation in the airways and intestine, but the major cause of mortality in CF is airway mucus accumulation, leading to bacterial colonization, inflammation and respiratory failure. Several drug targets are under evaluation to alleviate airway mucus obstruction in CF and one of these targets is the epithelial sodium channel ENaC. To explore effects of ENaC inhibitors on mucus properties, we used two model systems to investigate mucus characteristics, mucus attachment in mouse ileum and mucus bundle transport in piglet airways. We quantified mucus attachment in explants from CFTR null (CF) mice and tracheobronchial explants from newborn CFTR null (CF) piglets to evaluate effects of ENaC or sodium/hydrogen exchanger (NHE) inhibitors on mucus attachment. ENaC inhibitors detached mucus in the CF mouse ileum, although the ileum lacks ENaC expression. This effect was mimicked by two NHE inhibitors. Airway mucus bundles were immobile in untreated newborn CF piglets but were detached by the therapeutic drug candidate AZD5634 (patent WO, 2015140527). These results suggest that the ENaC inhibitor AZD5634 causes detachment of CF mucus in the ileum and airway via NHE inhibition and that drug design should focus on NHE instead of ENaC inhibition.
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Affiliation(s)
- Melania Giorgetti
- Department of Medical Biochemistry and Cell Biology, University of Gothenburg, Sweden.
| | - Nikolai Klymiuk
- Institute of Molecular Animal Breeding and Biotechnology, Gene Center, Ludwig-Maximilians-University Munich, Germany.
| | - Andrea Bähr
- Institute of Molecular Animal Breeding and Biotechnology, Gene Center, Ludwig-Maximilians-University Munich, Germany.
| | - Martin Hemmerling
- Research and Early Development, Respiratory, Inflammation and Autoimmunity (RIA), BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden.
| | - Lisa Jinton
- Research and Early Development, Respiratory, Inflammation and Autoimmunity (RIA), BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden.
| | - Robert Tarran
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, North Carolina, United States.
| | - Anna Malmgren
- Research and Early Development, Respiratory, Inflammation and Autoimmunity (RIA), BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden.
| | - Annika Åstrand
- Research and Early Development, Respiratory, Inflammation and Autoimmunity (RIA), BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden.
| | - Gunnar C Hansson
- Department of Medical Biochemistry and Cell Biology, University of Gothenburg, Sweden.
| | - Anna Ermund
- Department of Medical Biochemistry and Cell Biology, University of Gothenburg, Sweden.
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Sparks MA, Dilmen E, Ralph DL, Rianto F, Hoang TA, Hollis A, Diaz EJ, Adhikari R, Chew G, Petretto EG, Gurley SB, McDonough AA, Coffman TM. Vascular control of kidney epithelial transporters. Am J Physiol Renal Physiol 2021; 320:F1080-F1092. [PMID: 33969697 PMCID: PMC8285646 DOI: 10.1152/ajprenal.00084.2021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Revised: 04/23/2021] [Accepted: 05/05/2021] [Indexed: 01/03/2023] Open
Abstract
A major pathway in hypertension pathogenesis involves direct activation of ANG II type 1 (AT1) receptors in the kidney, stimulating Na+ reabsorption. AT1 receptors in tubular epithelia control expression and stimulation of Na+ transporters and channels. Recently, we found reduced blood pressure and enhanced natriuresis in mice with cell-specific deletion of AT1 receptors in smooth muscle (SMKO mice). Although impaired vasoconstriction and preserved renal blood flow might contribute to exaggerated urinary Na+ excretion in SMKO mice, we considered whether alterations in Na+ transporter expression might also play a role; therefore, we carried out proteomic analysis of key Na+ transporters and associated proteins. Here, we show that levels of Na+-K+-2Cl- cotransporter isoform 2 (NKCC2) and Na+/H+ exchanger isoform 3 (NHE3) are reduced at baseline in SMKO mice, accompanied by attenuated natriuretic and diuretic responses to furosemide. During ANG II hypertension, we found widespread remodeling of transporter expression in wild-type mice with significant increases in the levels of total NaCl cotransporter, phosphorylated NaCl cotransporter (Ser71), and phosphorylated NKCC2, along with the cleaved, activated forms of the α- and γ-epithelial Na+ channel. However, the increases in α- and γ-epithelial Na+ channel with ANG II were substantially attenuated in SMKO mice. This was accompanied by a reduced natriuretic response to amiloride. Thus, enhanced urinary Na+ excretion observed after cell-specific deletion of AT1 receptors from smooth muscle cells is associated with altered Na+ transporter abundance across epithelia in multiple nephron segments. These findings suggest a system of vascular-epithelial in the kidney, modulating the expression of Na+ transporters and contributing to the regulation of pressure natriuresis.NEW & NOTEWORTHY The use of drugs to block the renin-angiotensin system to reduce blood pressure is common. However, the precise mechanism for how these medications control blood pressure is incompletely understood. Here, we show that mice lacking angiotensin receptors specifically in smooth muscle cells lead to alternation in tubular transporter amount and function. Thus, demonstrating the importance of vascular-tubular cross talk in the control of blood pressure.
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Affiliation(s)
- Matthew A Sparks
- Division of Nephrology, Department of Medicine, Duke University School of Medicine, Durham, North Carolina
- Renal Section, Durham Veterans Affairs Health Care System, Durham, North Carolina
| | - Emre Dilmen
- Division of Nephrology, Department of Medicine, Duke University School of Medicine, Durham, North Carolina
| | - Donna L Ralph
- Department of Physiology and Neuroscience, Keck School of Medicine of the University of Southern California, Los Angeles, California
| | - Fitra Rianto
- Division of Nephrology, Department of Medicine, Duke University School of Medicine, Durham, North Carolina
| | - Thien A Hoang
- Division of Nephrology, Department of Medicine, Duke University School of Medicine, Durham, North Carolina
| | - Alison Hollis
- Division of Nephrology, Department of Medicine, Duke University School of Medicine, Durham, North Carolina
| | - Edward J Diaz
- Division of Nephrology, Department of Medicine, Duke University School of Medicine, Durham, North Carolina
| | - Rishav Adhikari
- Division of Nephrology, Department of Medicine, Duke University School of Medicine, Durham, North Carolina
| | - Gabriel Chew
- Program in Cardiovascular and Metabolic Disorders, Duke-NUS Medical School, Singapore
| | - Enrico G Petretto
- Program in Cardiovascular and Metabolic Disorders, Duke-NUS Medical School, Singapore
| | - Susan B Gurley
- Division of Nephrology and Hypertension, Oregon Health & Science University, Portland, Oregon
| | - Alicia A McDonough
- Department of Physiology and Neuroscience, Keck School of Medicine of the University of Southern California, Los Angeles, California
| | - Thomas M Coffman
- Division of Nephrology, Department of Medicine, Duke University School of Medicine, Durham, North Carolina
- Renal Section, Durham Veterans Affairs Health Care System, Durham, North Carolina
- Program in Cardiovascular and Metabolic Disorders, Duke-NUS Medical School, Singapore
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5
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Kang BS, Choi BY, Kho AR, Lee SH, Hong DK, Jeong JH, Kang DH, Park MK, Suh SW. An Inhibitor of the Sodium-Hydrogen Exchanger-1 (NHE-1), Amiloride, Reduced Zinc Accumulation and Hippocampal Neuronal Death after Ischemia. Int J Mol Sci 2020; 21:ijms21124232. [PMID: 32545865 PMCID: PMC7352629 DOI: 10.3390/ijms21124232] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2020] [Revised: 06/12/2020] [Accepted: 06/12/2020] [Indexed: 12/11/2022] Open
Abstract
Acidosis in the brain plays an important role in neuronal injury and is a common feature of several neurological diseases. It has been reported that the sodium–hydrogen exchanger-1 (NHE-1) is a key mediator of acidosis-induced neuronal injury. It modulates the concentration of intra- and extra-cellular sodium and hydrogen ions. During the ischemic state, excessive sodium ions enter neurons and inappropriately activate the sodium–calcium exchanger (NCX). Zinc can also enter neurons through voltage-gated calcium channels and NCX. Here, we tested the hypothesis that zinc enters the intracellular space through NCX and the subsequent zinc accumulation induces neuronal cell death after global cerebral ischemia (GCI). Thus, we conducted the present study to confirm whether inhibition of NHE-1 by amiloride attenuates zinc accumulation and subsequent hippocampus neuronal death following GCI. Mice were subjected to GCI by bilateral common carotid artery (BCCA) occlusion for 30 min, followed by restoration of blood flow and resuscitation. Amiloride (10 mg/kg, intraperitoneally (i.p.)) was immediately injected, which reduced zinc accumulation and neuronal death after GCI. Therefore, the present study demonstrates that amiloride attenuates GCI-induced neuronal injury, likely via the prevention of intracellular zinc accumulation. Consequently, we suggest that amiloride may have a high therapeutic potential for the prevention of GCI-induced neuronal death.
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Affiliation(s)
- Beom Seok Kang
- Department of Physiology, College of Medicine, Hallym University, Chuncheon 24252, Korea; (B.S.K.); (B.Y.C.); (A.R.K.); (S.H.L.); (D.K.H.); (J.H.J.); (M.K.P.)
| | - Bo Young Choi
- Department of Physiology, College of Medicine, Hallym University, Chuncheon 24252, Korea; (B.S.K.); (B.Y.C.); (A.R.K.); (S.H.L.); (D.K.H.); (J.H.J.); (M.K.P.)
| | - A Ra Kho
- Department of Physiology, College of Medicine, Hallym University, Chuncheon 24252, Korea; (B.S.K.); (B.Y.C.); (A.R.K.); (S.H.L.); (D.K.H.); (J.H.J.); (M.K.P.)
| | - Song Hee Lee
- Department of Physiology, College of Medicine, Hallym University, Chuncheon 24252, Korea; (B.S.K.); (B.Y.C.); (A.R.K.); (S.H.L.); (D.K.H.); (J.H.J.); (M.K.P.)
| | - Dae Ki Hong
- Department of Physiology, College of Medicine, Hallym University, Chuncheon 24252, Korea; (B.S.K.); (B.Y.C.); (A.R.K.); (S.H.L.); (D.K.H.); (J.H.J.); (M.K.P.)
| | - Jeong Hyun Jeong
- Department of Physiology, College of Medicine, Hallym University, Chuncheon 24252, Korea; (B.S.K.); (B.Y.C.); (A.R.K.); (S.H.L.); (D.K.H.); (J.H.J.); (M.K.P.)
| | - Dong Hyeon Kang
- Department of Medical Science, College of Medicine, Hallym University, Chuncheon 24252, Korea;
| | - Min Kyu Park
- Department of Physiology, College of Medicine, Hallym University, Chuncheon 24252, Korea; (B.S.K.); (B.Y.C.); (A.R.K.); (S.H.L.); (D.K.H.); (J.H.J.); (M.K.P.)
| | - Sang Won Suh
- Department of Physiology, College of Medicine, Hallym University, Chuncheon 24252, Korea; (B.S.K.); (B.Y.C.); (A.R.K.); (S.H.L.); (D.K.H.); (J.H.J.); (M.K.P.)
- Correspondence: ; Tel.: +82-10-8573-6364
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Wang F, Luo R, Peng K, Liu X, Xu C, Lu X, Soodvilai S, Yang T. Soluble (pro)renin receptor regulation of ENaC involved in aldosterone signaling in cultured collecting duct cells. Am J Physiol Renal Physiol 2020; 318:F817-F825. [PMID: 31841392 PMCID: PMC7099505 DOI: 10.1152/ajprenal.00436.2019] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Revised: 11/18/2019] [Accepted: 12/11/2019] [Indexed: 11/22/2022] Open
Abstract
We have previously shown that activation of (pro)renin receptor (PRR) induces epithelial Na+ channel (ENaC) activity in cultured collecting duct cells. Here, we examined the role of soluble PRR (sPRR), the cleavage product of PRR in ENaC regulation, and further tested its relevance to aldosterone signaling. In cultured mpkCCD cells, administration of recombinant histidine-tagged sPRR (sPRR-His) at 10 nM within minutes induced a significant and transient increase in the amiloride-sensitive short-circuit current as assessed using the Ussing chamber technique. The acute ENaC activation was blocked by the NADPH oxidase 1/4 inhibitor GKT137892 and siRNA against Nox4 but not the β-catenin inhibitor ICG-001. In primary rat inner medullary collecting duct cells, administration of sPRR-His at 10 nM for 24 h induced protein expression of the α-subunit but not β- or γ-subunits of ENaC, in parallel with upregulation of mRNA expression as well as promoter activity of the α-subunit. The transcriptional activation of α-ENaC was dependent on β-catenin signaling. Consistent results obtained by epithelial volt ohmmeter measurement of equivalent current and Ussing chamber determination of short-circuit current showed that aldosterone-induced transepithelial Na+ transport was inhibited by the PRR decoy inhibitor PRO20 and PF-429242, an inhibitor of sPRR-generating enzyme site-1 protease, and the response was restored by the addition of sPRR-His. Medium sPRR was elevated by aldosterone and inhibited by PF-429242. Taken together, these results demonstrate that sPRR induces two phases of ENaC activation via distinct mechanisms and functions as a mediator of the natriferic action of aldosterone.
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Affiliation(s)
- Fei Wang
- Department of Internal Medicine, University of Utah and Veterans Affairs Medical Center, Salt Lake City, Utah
| | - Renfei Luo
- Department of Internal Medicine, University of Utah and Veterans Affairs Medical Center, Salt Lake City, Utah
| | - Kexin Peng
- Department of Internal Medicine, University of Utah and Veterans Affairs Medical Center, Salt Lake City, Utah
- Institute of Hypertension, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China
| | - Xiyang Liu
- Institute of Hypertension, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China
| | - Chuanming Xu
- Department of Internal Medicine, University of Utah and Veterans Affairs Medical Center, Salt Lake City, Utah
| | - Xiaohan Lu
- Department of Internal Medicine, University of Utah and Veterans Affairs Medical Center, Salt Lake City, Utah
| | - Sunhapas Soodvilai
- Department of Physiology, Faculty of Science, Mahidol University, Bangkok, Thailand
| | - Tianxin Yang
- Department of Internal Medicine, University of Utah and Veterans Affairs Medical Center, Salt Lake City, Utah
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Mroz MS, Harvey BJ. Ursodeoxycholic acid inhibits ENaC and Na/K pump activity to restore airway surface liquid height in cystic fibrosis bronchial epithelial cells. Steroids 2019; 151:108461. [PMID: 31344409 DOI: 10.1016/j.steroids.2019.108461] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/25/2019] [Accepted: 07/15/2019] [Indexed: 01/22/2023]
Abstract
Cystic fibrosis (CF) is a disease caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) that in the airways result in reduced Cl- secretion and increased Na+ absorption, airway surface liquid (ASL) dehydration, decreased mucociliary clearance, infection and inflammation leading to lung injury. Cystic fibrosis patients often present with bile acids in the lower airways, however the effects of bile acids on ASL and ion transport in CF airways are not known. Secondary bile acids, such as ursodeoxycholic acid (UDCA), have been shown to modulate immune responses and epithelial ion transport. Here we investigated the effects of UDCA in normal and CF airway epithelial cell models. NuLi-1 (normal genotype) and CuFi-1 (CF genotype, Δ508/Δ508) primary immortalized airway epithelial cells were grown under an air-liquid interface. Electrogenic transepithelial ion transport was measured by short-circuit current (Isc) across cell monolayers mounted in Ussing chambers. We observed that UDCA (500 μM, 60 min, bilateral) decreased the basal Isc and ENaC currents in both NuLi-1 and CuFi-1 cells. UDCA inhibited the amiloride-sensitive ENaC current by 44% in NulI-1 monolayers and by 30% in CuFi-1 cells. Interestingly, UDCA also inhibited currents through the basolateral Na/K pump in both Nuli-1 and CuFi-1 monolayers without alterting the expression of ENaC or Na+/K+-ATPase proteins. The airway surface liquid height is regulated by transpeithelial Na+ absorption (ENaC) and Cl- secretion (CFTR) in normal airway but mainly by ENaC activity in CF epithelia when Cl- secretion is compromised by CFTR mutations. UDCA increased ASL height by 50% in Nuli-1 and by 40% in CUFI-1 monolayers. In conclusion, we demonstrate a previously unknown effect of UDCA to inhibit ENaC activity and increase ASL height in normal and CF human airway epithelial cells suggesting a therapeutic potential for UDCA in CF lung disease.
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Affiliation(s)
- Magdalena S Mroz
- Department of Molecular Medicine, Royal College of Surgeons in Ireland, RCSI ERC Beaumont Hospital, Dublin 9, Ireland
| | - Brian J Harvey
- Department of Molecular Medicine, Royal College of Surgeons in Ireland, RCSI ERC Beaumont Hospital, Dublin 9, Ireland; Centro di Estudios Cientificos CECs, Valdivia, Chile.
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Wu M, Liang C, Yu X, Song B, Yue Q, Zhai Y, Linck V, Cai Y, Niu N, Yang X, Zhang B, Wang Q, Zou L, Zhang S, Thai TL, Ma J, Sutliff RL, Zhang Z, Ma H. Lovastatin attenuates hypertension induced by renal tubule-specific knockout of ATP-binding cassette transporter A1, by inhibiting epithelial sodium channels. Br J Pharmacol 2019; 176:3695-3711. [PMID: 31222723 PMCID: PMC6715779 DOI: 10.1111/bph.14775] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2018] [Revised: 05/12/2019] [Accepted: 06/08/2019] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND AND PURPOSE We have shown that cholesterol is synthesized in the principal cells of renal cortical collecting ducts (CCD) and stimulates the epithelial sodium channels (ENaC). Here we have determined whether lovastatin, a cholesterol synthesis inhibitor, can antagonize the hypertension induced by activated ENaC, following deletion of the cholesterol transporter (ATP-binding cassette transporter A1; ABCA1). EXPERIMENTAL APPROACH We selectively deleted ABCA1 in the principal cells of mouse CCD and used the cell-attached patch-clamp technique to record ENaC activity. Western blot and immunofluorescence staining were used to evaluate protein expression levels. Systolic BP was measured with the tail-cuff method. KEY RESULTS Specific deletion of ABCA1 elevated BP and ENaC single-channel activity in the principal cells of CCD in mice. These effects were antagonized by lovastatin. ABCA1 deletion elevated intracellular cholesterol levels, which was accompanied by elevated ROS, increased expression of serum/glucocorticoid regulated kinase 1 (Sgk1), phosphorylated neural precursor cell-expressed developmentally down-regulated protein 4-2 (Nedd4-2) and furin, along with shorten the primary cilium, and reduced ATP levels in urine. CONCLUSIONS AND IMPLICATIONS These data suggest that specific deletion of ABCA1 in principal cells increases BP by stimulating ENaC channels via a cholesterol-dependent pathway which induces several secondary responses associated with oxidative stress, activated Sgk1/Nedd4-2, increased furin expression, and reduced cilium-mediated release of ATP. As ABCA1 can be blocked by cyclosporine A, these results suggest further investigation of the possible use of statins to treat CsA-induced hypertension.
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Affiliation(s)
- Ming‐Ming Wu
- Departments of Cardiology and Clinic Pharmacy, Institute of Metabolic Disease, Heilongjiang Academy of Medical Science, Key Laboratories of Education Ministry for Myocardial Ischemia Mechanism and TreatmentHarbin Medical University Cancer HospitalHarbinChina
- Department of PhysiologyEmory University School of MedicineAtlantaGeorgia
| | - Chen Liang
- Departments of Cardiology and Clinic Pharmacy, Institute of Metabolic Disease, Heilongjiang Academy of Medical Science, Key Laboratories of Education Ministry for Myocardial Ischemia Mechanism and TreatmentHarbin Medical University Cancer HospitalHarbinChina
| | - Xiao‐Di Yu
- Departments of Cardiology and Clinic Pharmacy, Institute of Metabolic Disease, Heilongjiang Academy of Medical Science, Key Laboratories of Education Ministry for Myocardial Ischemia Mechanism and TreatmentHarbin Medical University Cancer HospitalHarbinChina
| | - Bin‐Lin Song
- Departments of Cardiology and Clinic Pharmacy, Institute of Metabolic Disease, Heilongjiang Academy of Medical Science, Key Laboratories of Education Ministry for Myocardial Ischemia Mechanism and TreatmentHarbin Medical University Cancer HospitalHarbinChina
- Department of PhysiologyEmory University School of MedicineAtlantaGeorgia
| | - Qiang Yue
- Department of PhysiologyEmory University School of MedicineAtlantaGeorgia
| | - Yu‐Jia Zhai
- Department of PhysiologyEmory University School of MedicineAtlantaGeorgia
| | - Valerie Linck
- Department of PhysiologyEmory University School of MedicineAtlantaGeorgia
| | - Yong‐Xu Cai
- Departments of Cardiology and Clinic Pharmacy, Institute of Metabolic Disease, Heilongjiang Academy of Medical Science, Key Laboratories of Education Ministry for Myocardial Ischemia Mechanism and TreatmentHarbin Medical University Cancer HospitalHarbinChina
| | - Na Niu
- Departments of Cardiology and Clinic Pharmacy, Institute of Metabolic Disease, Heilongjiang Academy of Medical Science, Key Laboratories of Education Ministry for Myocardial Ischemia Mechanism and TreatmentHarbin Medical University Cancer HospitalHarbinChina
| | - Xu Yang
- Departments of Cardiology and Clinic Pharmacy, Institute of Metabolic Disease, Heilongjiang Academy of Medical Science, Key Laboratories of Education Ministry for Myocardial Ischemia Mechanism and TreatmentHarbin Medical University Cancer HospitalHarbinChina
| | - Bao‐Long Zhang
- Departments of Cardiology and Clinic Pharmacy, Institute of Metabolic Disease, Heilongjiang Academy of Medical Science, Key Laboratories of Education Ministry for Myocardial Ischemia Mechanism and TreatmentHarbin Medical University Cancer HospitalHarbinChina
| | - Qiu‐Shi Wang
- Departments of Cardiology and Clinic Pharmacy, Institute of Metabolic Disease, Heilongjiang Academy of Medical Science, Key Laboratories of Education Ministry for Myocardial Ischemia Mechanism and TreatmentHarbin Medical University Cancer HospitalHarbinChina
| | - Li Zou
- Department of PhysiologyEmory University School of MedicineAtlantaGeorgia
| | - Shuai Zhang
- Department of PhysiologyEmory University School of MedicineAtlantaGeorgia
| | - Tiffany L. Thai
- Department of PhysiologyEmory University School of MedicineAtlantaGeorgia
| | - Jing Ma
- Division of Pulmonary, Allergy, Critical Care and Sleep Medicine, Department of MedicineAtlanta Veterans Affairs Medical CenterDecaturGeorgia
| | - Roy L. Sutliff
- Division of Pulmonary, Allergy, Critical Care and Sleep Medicine, Department of MedicineAtlanta Veterans Affairs Medical CenterDecaturGeorgia
| | - Zhi‐Ren Zhang
- Departments of Cardiology and Clinic Pharmacy, Institute of Metabolic Disease, Heilongjiang Academy of Medical Science, Key Laboratories of Education Ministry for Myocardial Ischemia Mechanism and TreatmentHarbin Medical University Cancer HospitalHarbinChina
| | - He‐Ping Ma
- Department of PhysiologyEmory University School of MedicineAtlantaGeorgia
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9
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Chan LKY, Wang Y, Ng EKW, Leung PS. Na + /H + exchanger 3 blockade ameliorates type 2 diabetes mellitus via inhibition of sodium-glucose co-transporter 1-mediated glucose absorption in the small intestine. Diabetes Obes Metab 2018; 20:709-717. [PMID: 29110392 DOI: 10.1111/dom.13151] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/05/2017] [Revised: 10/12/2017] [Accepted: 10/29/2017] [Indexed: 01/02/2023]
Abstract
AIM To elucidate the role of Na+ /H+ exchanger 3 (NHE3) in sodium-glucose co-transporter 1 (SGLT1)-mediated small intestinal brush border membrane (BBM) glucose absorption and its functional implications in type 2 diabetes mellitus (T2DM). MATERIALS AND METHODS Human jejunal samples were obtained from patients undergoing gastrectomy. 14 C-glucose absorption was measured by liquid scintillation counting. NHE3 expression was suppressed by siRNA-mediated knockdown or augmented in Caco2 cells. Glucose and insulin tolerance in db/db and m+/db mice was assessed with oral and intraperitoneal glucose tolerance tests, and an intraperitoneal insulin tolerance test. Insulin resistance and β-cell function were assessed using homeostatic model assessment of insulin resistance and β-cell function. RESULTS NHE3 expression was upregulated in db/db mouse jejunal BBM and high-glucose-treated Caco2 cells. NHE3 blockade impaired SGLT1-mediated glucose absorption in human jejunum, m+/db and db/db mouse jejunums, and Caco2 cells, via serum/glucocorticoid-regulated kinase 1 (SGK1). NHE3 knockdown suppressed SGLT1-mediated glucose uptake and reduced mRNA and protein levels of SGK1 and SGLT1, which were conversely enhanced by NHE3 overexpression. Chronic S3226 treatment diminished postprandial glucose levels and ameliorated glucose intolerance in db/db mice. CONCLUSION NHE3 is essential in the modulation of small intestinal BBM glucose absorption. Our findings provide a rationale for future possible clinical application of NHE3 for treatment of T2DM through reducing intestinal glucose uptake and counteracting postprandial hyperglycaemia.
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Affiliation(s)
- Leo K Y Chan
- School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
| | - Yi Wang
- School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
| | - Enders K W Ng
- Department of Surgery, Prince of Wales Hospital, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
| | - Po Sing Leung
- School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
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10
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Pontes G, Pereira MH, Barrozo RB. Salt controls feeding decisions in a blood-sucking insect. J Insect Physiol 2017; 98:93-100. [PMID: 27989677 DOI: 10.1016/j.jinsphys.2016.12.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2016] [Revised: 12/07/2016] [Accepted: 12/10/2016] [Indexed: 06/06/2023]
Abstract
Salts are necessary for maintaining homeostatic conditions within the body of all living organisms. Like with all essential nutrients, deficient or excessive ingestion of salts can result in adverse health effects. The taste system is a primary sensory modality that helps animals to make adequate feeding decisions in terms of salt consumption. In this work we show that sodium and potassium chloride salts modulate the feeding behavior of Rhodnius prolixus in a concentration-dependent manner. Feeding is only triggered by an optimal concentration of any of these salts (0.1-0.15M) and in presence of the phagostimulant ATP. Conversely, feeding solutions that do not contain salts or have a high-salt concentration (>0.3M) are not ingested by insects. Notably, we show that feeding decisions of insects cannot be explained as an osmotic effect, because they still feed over hyperosmotic solutions bearing the optimal salt concentration. Insects perceive optimal-salt, no-salt and high-salt solutions as different gustatory information, as revealed the electromyogram recordings of the cibarial pump. Moreover, because insects do a continuous gustatory monitoring of the incoming food during feeding, sudden changes beyond the optimal sodium concentration decrease and even inhibit feeding. The administration of amiloride, a sodium channel blocker, noticeably reduces the ingestion of the optimal sodium solution but not of the optimal potassium solution. Salt detection seems to occur at least through two salt receptors, one amiloride-sensitive and another amiloride-insensitive. Our results confirm the importance of the gustatory system in R. prolixus, showing the relevant role that salts play on their feeding decisions.
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Affiliation(s)
- Gina Pontes
- Grupo de Neuroetología de Insectos Vectores, Laboratorio Fisiología de Insectos, IBBEA, CONICET-UBA, DBBE, Facultad Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, BA, Argentina
| | - Marcos H Pereira
- Laboratório de Fisiologia de Insetos Hematófagos, Departamento de Parasitologia, ICB, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Romina B Barrozo
- Grupo de Neuroetología de Insectos Vectores, Laboratorio Fisiología de Insectos, IBBEA, CONICET-UBA, DBBE, Facultad Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, BA, Argentina.
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11
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Yang C, Xiong Y, Zhang SS, An FM, Sun J, Zhang QL, Zhan Q. Regulating effect of TongXie-YaoFang on colonic epithelial secretion via Cl - and HCO 3- channel. World J Gastroenterol 2016; 22:10584-10591. [PMID: 28082810 PMCID: PMC5192269 DOI: 10.3748/wjg.v22.i48.10584] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/23/2016] [Revised: 10/10/2016] [Accepted: 11/16/2016] [Indexed: 02/06/2023] Open
Abstract
AIM To investigate the pharmacological effect of TongXie-YaoFang (TXYF) formula, a Chinese herbal formula, on Diarrhea-predominant irritable bowel syndrome (D-IBS) rats.
METHODS In a neonatal maternal separation plus restraint stress (NMS + RS) model of D-IBS, male Sprague Dawley rats were randomly divided into two groups (NMS + RS group and TXYF-formula group) with no handlings were used as controls (NH group). Starting from postnatal day 60, rats in TXYF-formula group were administered TXYF-formula (4.92 g/100 g bodyweight) orally twice a day for 14 consecutive days while NH group and NMS + RS group were given distilled water. Using short-circuit current technology, we observed 5-HT-induced changes of current across ion channels, such as cystic fibrosis transmembrane conductance regulator (CFTR) Cl- channel, epithelial Na+ channel (ENaC), Ca2+-dependent Cl- channel (CACC), Na+-K+-2Cl- co-transporter (NKCC), and Na+-HCO3- co-transporter (NBC), in the colonic epithelium of three groups after exposure to drugs and specific blockers with a Power Lab System (AD Instruments International).
RESULTS Under basal conditions, the changes of short-circuit current (∆Isc, µA/cm2) induced by 5-HT were similar in NH group and TXYF-formula group, and both higher than NMS + RS group (70.86 µA/cm2 ± 12.32 µA/cm2, 67.67 µA/cm2 ± 11.68 µA/cm2 vs 38.8 µA/cm2 ± 7.25 µA/cm2, P < 0.01, respectively). When CACC was blocked by 4,4′-diisothiocyanato-stilbene-2,2′-disulfonic acid, 5-HT-induced ∆Isc was smaller in NMS + RS group than in NH group and TXYF-formula group, respectively (48.41 µA/cm2 ± 13.15 µA/cm2 vs 74.62 µA/cm2 ± 10.73 µA/cm2, 69.22 µA/cm2 ± 11.7 µA/cm2, P < 0.05, respectively). The similar result could be obtained when ENaC was blocked by Amiloride (44.69 µA/cm2 ± 12.58 µA/cm2 vs 62.05 µA/cm2 ± 11.26 µA/cm2, 62.11 µA/cm2 ± 12.01 µA/cm2, P < 0.05, respectively). However, when CFTR Cl- channel was blocked by 1,1-dimethyl piperidinium chloride (DPC), 5-HT-induced ∆Isc did not significantly differ in three groups (42.28 µA/cm2 ± 10.61 µA/cm2 vs 51.48 µA/cm2 ± 6.56 µA/cm2 vs 47.75 µA/cm2 ± 7.99 µA/cm2, P > 0.05, respectively). The similar results could also be obtained in three groups when NBC and NKCC were respectively blocked by their blockers.
CONCLUSION TXYF-formula can regulate the Cl- and HCO3- secretion of colonic mucosa via CFTR Cl- channel, Cl-/HCO3- exchanger, NBC and NKCC co-transporters.
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12
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Vílchez MC, Morini M, Peñaranda DS, Gallego V, Asturiano JF, Pérez L. Sodium affects the sperm motility in the European eel. Comp Biochem Physiol A Mol Integr Physiol 2016; 198:51-8. [PMID: 27085371 DOI: 10.1016/j.cbpa.2016.04.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Revised: 04/04/2016] [Accepted: 04/09/2016] [Indexed: 11/17/2022]
Abstract
The role of seminal plasma sodium and activation media sodium on sperm motility was examined by selectively removing the element from these two media, in European eel sperm. Sperm size (sperm head area) was also measured using an ASMA (Automated Sperm Morphometry Analyses) system, in the different conditions. Intracellular sodium [Na(+)]i was quantitatively analyzed by first time in the spermatozoa from a marine fish species. Measurement of [Na(+)]i was done before and after motility activation, by Flow Cytometry, using CoroNa Green AM as a dye. Sperm motility activation induced an increase in [Na(+)]i, from 96.72mM in quiescent stage to 152.21mM post-activation in seawater. A significant decrease in sperm head area was observed post-activation in seawater. There was a notable reduction in sperm motility when sodium was removed from the seminal plasma, but not when it was removed from the activation media. Sodium removal was also linked to a significant reduction in sperm head area in comparison to the controls. Our results indicate that the presence of the ion Na(+) in the seminal plasma (or in the extender medium) is necessary for the preservation of sperm motility in European eel, probably because it plays a role in maintaining an appropriate sperm cell volume in the quiescent stage of the spermatozoa.
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Affiliation(s)
- M Carmen Vílchez
- Grupo de Acuicultura y Biodiversidad, Instituto de Ciencia y Tecnología Animal, Universitat Politècnica de València, Camino de Vera, s/n., 46022 Valencia, Spain
| | - Marina Morini
- Grupo de Acuicultura y Biodiversidad, Instituto de Ciencia y Tecnología Animal, Universitat Politècnica de València, Camino de Vera, s/n., 46022 Valencia, Spain
| | - David S Peñaranda
- Grupo de Acuicultura y Biodiversidad, Instituto de Ciencia y Tecnología Animal, Universitat Politècnica de València, Camino de Vera, s/n., 46022 Valencia, Spain
| | - Víctor Gallego
- Grupo de Acuicultura y Biodiversidad, Instituto de Ciencia y Tecnología Animal, Universitat Politècnica de València, Camino de Vera, s/n., 46022 Valencia, Spain
| | - Juan F Asturiano
- Grupo de Acuicultura y Biodiversidad, Instituto de Ciencia y Tecnología Animal, Universitat Politècnica de València, Camino de Vera, s/n., 46022 Valencia, Spain
| | - Luz Pérez
- Grupo de Acuicultura y Biodiversidad, Instituto de Ciencia y Tecnología Animal, Universitat Politècnica de València, Camino de Vera, s/n., 46022 Valencia, Spain.
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13
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Saraví FD, González Otárula KA, Carra GE, Ibáñez JE. Aldosterone increases oxygen consumption of rectal epithelia of normal, sodium-deprived and sodiumloaded rats. Acta Gastroenterol Latinoam 2015; 45:203-211. [PMID: 28590603] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
INTRODUCTION The colonic epithelium is a classical aldosterone target, but the effect of the hormone on the oxygen consumption rate (QO2 ) of this tissue is unknown. Objectives. We aimed at assessing, in the rectal epithelium of rats fed with diets of different sodium content, the effect of epithelial sodium channel (ENaC) blockade on short-circuit current (ISC ) and QO2 , and the acute effect of aldosterone incubation on ISC and QO2 . METHODS Adult male rats were fed with normal, low or high-sodium diets for 8 days. Plasma sodium and serum aldosterone were measured. Isolated mucosa preparations from the rectal portion of the colon were mounted in Ussing chambers modified to measure ISC and QO2. RESULTS Baseline ISC and QO2 were highest in sodium-deprived rats. Both were proportionally reduced by amiloride (0.1 mM) in this group and in the normal sodium group, but not in sodium-loaded rats. In separate experiments, incubation with aldosterone (10 nM) for 7 h increased ISC and QO2 in all groups; increases were larger in the normal and sodium-loaded groups. Amiloride decreased both ISC and QO2 , abolishing the differences between groups. Linear regression of the decrease in QO2 and ISC after amiloride showed the steepest slope for the sodium-deprived group and the flattest one for the sodium-loaded group. CONCLUSIONS Baseline epithelial QO2 of sodium-deprived and control rats is reduced by ENaC blockade. Aldosterone increased QO2 proportionally to ISC augmentation in all groups, but the coupling between aerobic metabolism and electrogenic transport seems more efficient in sodium-deprived animals.
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14
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Cerecedo D, Martínez-Vieyra I, Alonso-Rangel L, Benítez-Cardoza C, Ortega A. Epithelial sodium channel modulates platelet collagen activation. Eur J Cell Biol 2014; 93:127-36. [PMID: 24679405 DOI: 10.1016/j.ejcb.2014.02.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2013] [Revised: 01/30/2014] [Accepted: 02/24/2014] [Indexed: 12/14/2022] Open
Abstract
Activated platelets adhere to the exposed subendothelial extracellular matrix and undergo a rapid cytoskeletal rearrangement resulting in shape change and release of their intracellular dense and alpha granule contents to avoid hemorrhage. A central step in this process is the elevation of the intracellular Ca(2+) concentration through its release from intracellular stores and on throughout its influx from the extracellular space. The Epithelial sodium channel (ENaC) is a highly selective Na(+) channel involved in mechanosensation, nociception, fluid volume homeostasis, and control of arterial blood pressure. The present study describes the expression, distribution, and participation of ENaC in platelet migration and granule secretion using pharmacological inhibition with amiloride. Our biochemical and confocal analysis in suspended and adhered platelets suggests that ENaC is associated with Intermediate filaments (IF) and with Dystrophin-associated proteins (DAP) via α-syntrophin and β-dystroglycan. Migration assays, quantification of soluble P-selectin, and serotonin release suggest that ENaC is dispensable for migration and alpha and dense granule secretion, whereas Na(+) influx through this channel is fundamental for platelet collagen activation.
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Affiliation(s)
- Doris Cerecedo
- Laboratorio de Hematobiología, Escuela Nacional de Medicina y Homeopatía (ENMH), Instituto Politécnico Nacional (IPN), Mexico City, Mexico.
| | - Ivette Martínez-Vieyra
- Laboratorio de Hematobiología, Escuela Nacional de Medicina y Homeopatía (ENMH), Instituto Politécnico Nacional (IPN), Mexico City, Mexico
| | - Lea Alonso-Rangel
- Laboratorio de Hematobiología, Escuela Nacional de Medicina y Homeopatía (ENMH), Instituto Politécnico Nacional (IPN), Mexico City, Mexico
| | - Claudia Benítez-Cardoza
- Laboratorio de Bioquímica, Escuela Nacional de Medicina y Homeopatía (ENMH), Instituto Politécnico Nacional (IPN), Mexico City, Mexico
| | - Arturo Ortega
- Departamento de Genética y Biología Molecular, Centro de Investigación y de Estudios Avanzados del IPN (Cinvestav-IPN), Mexico City, Mexico
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15
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Hosseinzadeh Z, Luo D, Sopjani M, Bhavsar SK, Lang F. Down-regulation of the epithelial Na⁺ channel ENaC by Janus kinase 2. J Membr Biol 2014; 247:331-8. [PMID: 24562791 DOI: 10.1007/s00232-014-9636-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2013] [Accepted: 01/29/2014] [Indexed: 11/26/2022]
Abstract
Janus kinase-2 (JAK2), a signaling molecule mediating effects of various hormones including leptin and growth hormone, has previously been shown to modify the activity of several channels and carriers. Leptin is known to inhibit and growth hormone to stimulate epithelial Na(+) transport, effects at least partially involving regulation of the epithelial Na(+) channel ENaC. However, no published evidence is available regarding an influence of JAK2 on the activity of the epithelial Na(+) channel ENaC. In order to test whether JAK2 participates in the regulation of ENaC, cRNA encoding ENaC was injected into Xenopus oocytes with or without additional injection of cRNA encoding wild type JAK2, gain-of-function (V617F)JAK2 or inactive (K882E)JAK2. Moreover, ENaC was expressed with or without the ENaC regulating ubiquitin ligase Nedd4-2 with or without JAK2, (V617F)JAK2 or (K882E)JAK2. ENaC was determined from amiloride (50 μM)-sensitive current (I(amil)) in dual electrode voltage clamp. Moreover, I(amil) was determined in colonic tissue utilizing Ussing chambers. As a result, the I(amil) in ENaC-expressing oocytes was significantly decreased following coexpression of JAK2 or (V617F)JAK2, but not by coexpression of (K882E)JAK2. Coexpression of JAK2 and Nedd4-2 decreased I(amil) in ENaC-expressing oocytes to a larger extent than coexpression of Nedd4-2 alone. Exposure of ENaC- and JAK2-expressing oocytes to JAK2 inhibitor AG490 (40 μM) significantly increased I(amil). In colonic epithelium, I(amil) was significantly enhanced by AG490 pretreatment (40 μM, 1 h). In conclusion, JAK2 is a powerful inhibitor of ENaC.
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Affiliation(s)
- Zohreh Hosseinzadeh
- Department of Physiology, University of Tübingen, Gmelinstr. 5, 72076, Tübingen, Germany
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16
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Haerteis S, Krappitz M, Bertog M, Krappitz A, Baraznenok V, Henderson I, Lindström E, Murphy JE, Bunnett NW, Korbmacher C. Proteolytic activation of the epithelial sodium channel (ENaC) by the cysteine protease cathepsin-S. Pflugers Arch 2012; 464:353-65. [PMID: 22864553 PMCID: PMC3448907 DOI: 10.1007/s00424-012-1138-3] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2012] [Revised: 07/10/2012] [Accepted: 07/10/2012] [Indexed: 01/16/2023]
Abstract
Proteolytic processing of the amiloride-sensitive epithelial sodium channel (ENaC) by serine proteases is known to be important for channel activation. Inappropriate ENaC activation by proteases may contribute to the pathophysiology of cystic fibrosis and could be involved in sodium retention and the pathogenesis of arterial hypertension in the context of renal disease. We hypothesized that in addition to serine proteases, cathepsin proteases may activate ENaC. Cathepsin proteases belong to the group of cysteine proteases and play a pathophysiological role in inflammatory diseases. Under pathophysiological conditions, cathepsin-S (Cat-S) may reach ENaC in the apical membrane of epithelial cells. The aim of this study was to investigate the effect of purified Cat-S on human ENaC heterologously expressed in Xenopus laevis oocytes and on ENaC-mediated sodium transport in cultured M-1 mouse renal collecting duct cells. We demonstrated that Cat-S activates amiloride-sensitive whole-cell currents in ENaC-expressing oocytes. The stimulatory effect of Cat-S was preserved at pH 5. ENaC stimulation by Cat-S was associated with the appearance of a γENaC cleavage fragment at the plasma membrane indicating proteolytic channel activation. Mutating two valine residues (V182 and V193) in the critical region of γENaC prevented proteolytic activation of ENaC by Cat-S. Pre-incubation of the oocytes with the Cat-S inhibitor morpholinurea-leucine-homophenylalanine-vinylsulfone-phenyl (LHVS) prevented the stimulatory effect of Cat-S on ENaC. In contrast, LHVS had no effect on ENaC activation by the prototypical serine proteases trypsin and chymotrypsin. Cat-S also stimulated ENaC in differentiated renal epithelial cells. These findings demonstrate that the cysteine protease Cat-S can activate ENaC which may be relevant under pathophysiological conditions.
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Affiliation(s)
- Silke Haerteis
- Institut für Zelluläre und Molekulare Physiologie, Friedrich-Alexander-Universität Erlangen-Nürnberg, Waldstr. 6, 91054 Erlangen, Germany
| | - Matteus Krappitz
- Institut für Zelluläre und Molekulare Physiologie, Friedrich-Alexander-Universität Erlangen-Nürnberg, Waldstr. 6, 91054 Erlangen, Germany
| | - Marko Bertog
- Institut für Zelluläre und Molekulare Physiologie, Friedrich-Alexander-Universität Erlangen-Nürnberg, Waldstr. 6, 91054 Erlangen, Germany
| | - Annabel Krappitz
- Institut für Zelluläre und Molekulare Physiologie, Friedrich-Alexander-Universität Erlangen-Nürnberg, Waldstr. 6, 91054 Erlangen, Germany
| | | | | | | | - Jane E. Murphy
- Center for the Neurobiology of Digestive Diseases, Department of Surgery, University of California San Francisco, San Francisco, CA USA
| | - Nigel W. Bunnett
- Monash Institute of Pharmaceutical Sciences, 381 Royal Parade, Parkville, VIC 3052 Australia
| | - Christoph Korbmacher
- Institut für Zelluläre und Molekulare Physiologie, Friedrich-Alexander-Universität Erlangen-Nürnberg, Waldstr. 6, 91054 Erlangen, Germany
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Abstract
About one third of the population worldwide is supposed to be salt sensitive which is a major cause for arterial hypertension later in life. For preventive actions it is thus desirable to identify salt-sensitive individuals before the appearance of clinical symptoms. Recent observations suggest that the vascular endothelium consists of two salt-sensitive barriers in series, the glycocalyx that buffers sodium and the endothelial cell membrane that contains sodium channels. Glycocalyx sodium buffer capacity and sodium channel activity are conversely related to each other. For proof of concept, a so-called salt provocation test (SPT) was developed that should unmask vascular salt sensitivity in humans at virtually any age. Nineteen healthy subjects, ranging from 25 to 63 years of age, underwent two series of 1-h blood pressure measurements after acute ingestion of a salt cocktail with or without addition of a sodium channel blocker effective in vascular endothelium. Differential analysis of the changes in diastolic blood pressure (net ∆DP) identified 12 individuals (63 %) as being salt resistant (net ∆DP = −0.05 ± 0.62 mmHg) and seven individuals (37 %) as being salt sensitive (net ∆DP = +6.98 ± 0.75 mmHg). Vascular salt sensitivity was not related to the age of the study participants. It is concluded that the SPT could be useful for identifying vascular salt sensitivity in humans already early in life.
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Affiliation(s)
- Hans Oberleithner
- Institute of Physiology II, University of Muenster, Robert-Koch-Strasse 27b, 48149, Muenster, Germany.
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