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Li H, Valkenier H, Thorne AG, Dias CM, Cooper JA, Kieffer M, Busschaert N, Gale PA, Sheppard DN, Davis AP. Anion carriers as potential treatments for cystic fibrosis: transport in cystic fibrosis cells, and additivity to channel-targeting drugs. Chem Sci 2019; 10:9663-9672. [PMID: 32055336 PMCID: PMC6984391 DOI: 10.1039/c9sc04242c] [Citation(s) in RCA: 67] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Accepted: 09/09/2019] [Indexed: 12/12/2022] Open
Abstract
Defective anion transport is a hallmark of the genetic disease cystic fibrosis (CF). One approach to restore anion transport to CF cells utilises alternative pathways for transmembrane anion transport, including artificial anion carriers (anionophores). Here, we screened 22 anionophores for biological activity using fluorescence emission from the halide-sensitive yellow fluorescent protein. Three compounds possessed anion transport activity similar to or greater than that of a bis-(p-nitrophenyl)ureidodecalin previously shown to have promising biological activity. Anion transport by these anionophores was concentration-dependent and persistent. All four anionophores mediated anion transport in CF cells, and their activity was additive to rescue of the predominant disease-causing variant F508del-CFTR using the clinically-licensed drugs lumacaftor and ivacaftor. Toxicity was variable but minimal at the lower end. The results provide further evidence that anionophores, by themselves or together with other treatments that restore anion transport, offer a potential therapeutic strategy for CF.
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Affiliation(s)
- Hongyu Li
- School of Physiology , Pharmacology and Neuroscience , University of Bristol , Biomedical Sciences Building, University Walk , Bristol BS8 1TD , UK .
| | - Hennie Valkenier
- School of Chemistry , University of Bristol , Cantock's Close , Bristol BS8 1TS , UK .
| | - Abigail G Thorne
- School of Chemistry , University of Bristol , Cantock's Close , Bristol BS8 1TS , UK .
| | - Christopher M Dias
- School of Chemistry , University of Bristol , Cantock's Close , Bristol BS8 1TS , UK .
| | - James A Cooper
- School of Chemistry , University of Bristol , Cantock's Close , Bristol BS8 1TS , UK .
| | - Marion Kieffer
- School of Chemistry , University of Bristol , Cantock's Close , Bristol BS8 1TS , UK .
| | | | - Philip A Gale
- Chemistry , University of Southampton , Southampton SO17 1BJ , UK .
| | - David N Sheppard
- School of Physiology , Pharmacology and Neuroscience , University of Bristol , Biomedical Sciences Building, University Walk , Bristol BS8 1TD , UK .
| | - Anthony P Davis
- School of Chemistry , University of Bristol , Cantock's Close , Bristol BS8 1TS , UK .
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Dbouk HA, Huang CL, Cobb MH. Hypertension: the missing WNKs. Am J Physiol Renal Physiol 2016; 311:F16-27. [PMID: 27009339 PMCID: PMC4967160 DOI: 10.1152/ajprenal.00358.2015] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2015] [Accepted: 03/16/2016] [Indexed: 12/23/2022] Open
Abstract
The With no Lysine [K] (WNK) family of enzymes are central in the regulation of blood pressure. WNKs have been implicated in hereditary hypertension disorders, mainly through control of the activity and levels of ion cotransporters and channels. Actions of WNKs in the kidney have been heavily investigated, and recent studies have provided insight into not only the regulation of these enzymes but also how mutations in WNKs and their interacting partners contribute to hypertensive disorders. Defining the roles of WNKs in the cardiovascular system will provide clues about additional mechanisms by which WNKs can regulate blood pressure. This review summarizes recent developments in the regulation of the WNK signaling cascade and its role in regulation of blood pressure.
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Affiliation(s)
- Hashem A Dbouk
- Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, Texas; and
| | - Chou-Long Huang
- Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Melanie H Cobb
- Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, Texas; and
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3
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Cong D, Zhu W, Kuo JS, Hu S, Sun D. Ion transporters in brain tumors. Curr Med Chem 2016; 22:1171-81. [PMID: 25620102 DOI: 10.2174/0929867322666150114151946] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2014] [Revised: 01/05/2015] [Accepted: 01/08/2015] [Indexed: 11/22/2022]
Abstract
Ion transporters are important in regulation of ionic homeostasis, cell volume, and cellular signal transduction under physiological conditions. They have recently emerged as important players in cancer progression. In this review, we discussed two important ion transporter proteins, sodium-potassium-chloride cotransporter isoform 1 (NKCC-1) and sodium-hydrogen exchanger isoform 1 (NHE-1) in Glioblastoma multiforme (GBM) and other malignant tumors. NKCC-1 is a Na(+)- dependent Cl(-) transporter that mediates the movement of Na(+), K(+), and Cl(-) ions across the plasma membrane and maintains cell volume and intracellular K(+) and Cl(-) homeostasis. NHE-1 is a ubiquitously expressed cell membrane protein which regulates intracellular pH (pH(i)) and extracellular pH (pH(e)) homeostasis and cell volume. Here, we summarized recent pre-clinical experimental studies on NKCC-1 and NHE-1 in GBM and other malignant tumors, such as breast cancer, hepatocellular carcinoma, and lung cancer cells. These studies illustrated that pharmacological inhibition or down-regulation of these ion transporter proteins reduces proliferation, increases apoptosis, and suppresses migration and invasion of cancer cells. These new findings reveal the potentials of these ion transporters as new targets for cancer diagnosis and/or treatment.
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Affiliation(s)
| | | | | | | | - Dandan Sun
- Department of Neurology, University of Pittsburgh Medical School, S-598 South Biomedical Science Tower (BST), 3500 Terrace St., Pittsburgh, PA 15213, USA.
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Ghorai A, Achari B, Chattopadhyay P. Self-assembly of cyclic peptides and peptidomimetic macrocycles: linking structure with function. Tetrahedron 2016. [DOI: 10.1016/j.tet.2016.04.071] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Bisri T, Utomo BA, Fuadi I. Exogenous lactate infusion improved neurocognitive function of patients with mild traumatic brain injury. Asian J Neurosurg 2016; 11:151-9. [PMID: 27057222 PMCID: PMC4802937 DOI: 10.4103/1793-5482.145375] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
BACKGROUND Many studies showed a better recovery of cognitive function after administration of exogenous lactate during moderate-severe traumatic brain injury. However, the study evaluating lactate effect on mild traumatic brain injury is still limited. AIMS To evaluate the effect of exogenous lactate on cognitive function in mild traumatic brain injury patients. SETTINGS AND DESIGN Prospective, single blind, randomized controlled study on 60 mild traumatic brain injury patients who were undergoing neurosurgery. MATERIALS AND METHODS Subjects were randomly assigned into hyperosmolar sodium lactate (HSL) group or hyperosmolar sodium chloride (HSS) group. Patients in each group received either intravenous infusion of HSL or NaCl 3% at 1.5 ml/KgBW within 15 min before neurosurgery. During the surgery, patients in both groups received maintenance infusion of NaCl 0.9% at 1.5 ml/KgBW/hour. STATISTICAL ANALYSIS Cognitive function, as assessed by Mini-Mental State Examination (MMSE) score at 24 h, 30 and 90 days post-surgery, was analyzed by Anova repeated measures test. RESULTS The MMSE score improvement was significantly better in HSL group than HSS group (P < 0.001). In HSL group the MMSE score improved from 16.00 (13.75-18.00) at baseline to 21.00 (18.75-22.00); 25.00 (23.75-26.00); 28.00 (27.00-29.00) at 24 h, 30, 90 days post-surgery, respectively. In contrast, in HSS group the MMSE score almost unchanged at 24 h and only slightly increased at 30 and 90 days post-surgery. CONCLUSIONS Hyperosmolar sodium lactate infusion during mild traumatic brain injury improved cognitive function better than sodium chloride 3%.
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Affiliation(s)
- Tatang Bisri
- Department of Anesthesiology and Intensive Care, Faculty of Medicine, Universitas Padjadjaran, Hasan Sadikin Hospital, Bandung, Indonesia
| | - Billy A. Utomo
- Department of Anesthesiology and Intensive Care, Faculty of Medicine, Universitas Padjadjaran, Hasan Sadikin Hospital, Bandung, Indonesia
| | - Iwan Fuadi
- Department of Anesthesiology and Intensive Care, Faculty of Medicine, Universitas Padjadjaran, Hasan Sadikin Hospital, Bandung, Indonesia
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Milano D, Benedetti B, Boccalon M, Brugnara A, Iengo E, Tecilla P. Anion transport across phospholipid membranes mediated by a diphosphine–Pd(ii) complex. Chem Commun (Camb) 2014; 50:9157-60. [DOI: 10.1039/c4cc02881c] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Swelling-activated Cl− currents and intracellular CLC-3 are involved in proliferation of human pulmonary artery smooth muscle cells. J Hypertens 2014; 32:318-30. [DOI: 10.1097/hjh.0000000000000013] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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Alfonso I, Quesada R. Biological activity of synthetic ionophores: ion transporters as prospective drugs? Chem Sci 2013. [DOI: 10.1039/c3sc50882j] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
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Quesada R. Membrane Transport. Supramol Chem 2012. [DOI: 10.1002/9780470661345.smc173] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Elie CR, Charbonneau M, Schmitzer AR. An anion structure–activity relationship of imidazolium-based synthetic transporters. MEDCHEMCOMM 2012. [DOI: 10.1039/c2md20107k] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Cefaratti C, Romani A. Modulation of Na+/Mg2+ exchanger stoichiometry ratio by Cl− ions in basolateral rat liver plasma membrane vesicles. Mol Cell Biochem 2011; 351:133-42. [DOI: 10.1007/s11010-011-0720-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2010] [Accepted: 01/05/2011] [Indexed: 10/18/2022]
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Elie CR, Noujeim N, Pardin C, Schmitzer AR. Uncovering new properties of imidazolium salts: Cl−transport and supramolecular regulation of their transmembrane activity. Chem Commun (Camb) 2011; 47:1788-90. [DOI: 10.1039/c0cc04280c] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Hennig A, Fischer L, Guichard G, Matile S. Anion−Macrodipole Interactions: Self-Assembling Oligourea/Amide Macrocycles as Anion Transporters that Respond to Membrane Polarization. J Am Chem Soc 2009; 131:16889-95. [DOI: 10.1021/ja9067518] [Citation(s) in RCA: 98] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Andreas Hennig
- Department of Organic Chemistry, University of Geneva, Geneva, Switzerland, and CNRS, Institut de Biologie Moléculaire et Cellulaire, Laboratoire d’Immunologie et Chimie Thérapeutiques, Strasbourg, France
| | - Lucile Fischer
- Department of Organic Chemistry, University of Geneva, Geneva, Switzerland, and CNRS, Institut de Biologie Moléculaire et Cellulaire, Laboratoire d’Immunologie et Chimie Thérapeutiques, Strasbourg, France
| | - Gilles Guichard
- Department of Organic Chemistry, University of Geneva, Geneva, Switzerland, and CNRS, Institut de Biologie Moléculaire et Cellulaire, Laboratoire d’Immunologie et Chimie Thérapeutiques, Strasbourg, France
| | - Stefan Matile
- Department of Organic Chemistry, University of Geneva, Geneva, Switzerland, and CNRS, Institut de Biologie Moléculaire et Cellulaire, Laboratoire d’Immunologie et Chimie Thérapeutiques, Strasbourg, France
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Li X, Shen B, Yao XQ, Yang D. Synthetic Chloride Channel Regulates Cell Membrane Potentials and Voltage-Gated Calcium Channels. J Am Chem Soc 2009; 131:13676-80. [DOI: 10.1021/ja902352g] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Xiang Li
- Morningside Laboratory for Chemical Biology, Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong, People's Republic of China, and Department of Physiology, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong, People's Republic of China
| | - Bing Shen
- Morningside Laboratory for Chemical Biology, Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong, People's Republic of China, and Department of Physiology, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong, People's Republic of China
| | - Xiao-Qiang Yao
- Morningside Laboratory for Chemical Biology, Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong, People's Republic of China, and Department of Physiology, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong, People's Republic of China
| | - Dan Yang
- Morningside Laboratory for Chemical Biology, Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong, People's Republic of China, and Department of Physiology, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong, People's Republic of China
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Ringman Uggla A, Zelenina M, Eklöf AC, Aperia A, Frenckner B. Expression of chloride channels in trachea-occluded hyperplastic lungs and nitrofen-induced hypoplastic lungs in rats. Pediatr Surg Int 2009; 25:799-806. [PMID: 19652985 DOI: 10.1007/s00383-009-2423-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 07/17/2009] [Indexed: 11/29/2022]
Abstract
BACKGROUND Congenital diaphragmatic hernia is accompanied by pulmonary hypoplasia. Fetal lung growth is dependent on the secretion of lung liquid, in which Cl(-) secretion by the pulmonary epithelium plays a crucial role. A decrease of lung liquid production during fetal development renders marked pulmonary hypoplasia, while accelerated fetal lung growth in the form of pulmonary hyperplasia can be achieved by in utero tracheal occlusion (TO). Cl(-) secretion presumably involves NKCC-1, the primary basolateral Cl(-) entry pathway in airway epithelia, coupled to an apical Cl(-) exit pathway. The chloride channels ClC-2, -3 and -5, members of the CLC gene family, are all localized to the apical membrane of fetal respiratory epithelia, which makes them possible candidates for being mediators of fetal apical Cl(-) secretion. The aim of the study was to examine the potential of ClC-2, -3 and -5 as alternative apical airway epithelial Cl(-) channels in normal lung development and their possible role in the development of hypoplastic lungs in CDH. We also wanted to examine ClC-2, -3 and -5 together with the NKCC-1 in hyperplastic lungs created by TO. METHODS Pregnant Sprague-Dawley rat dams were given nitrofen on gestational day 9.5 to induce pulmonary hypoplasia. Controls were given only olive oil. The rat fetuses were removed on days 17, 19 and 21. Hyperplastic lungs were created by intrauterine TO of rat fetuses on day 19 and the lungs were harvested on day 21. The pulmonary expression of ClC-2, -3, -5 and NKCC-1 was then analyzed using Western blot. RESULTS We found that the temporal expression of ClC-2 and -3 in normal fetal lungs points toward a developmental regulation. ClC-2 and -3 were also both down-regulated on day 21 in hypoplastic CDH lungs. In TO induced hyperplastic lungs, the levels of ClC-2 were found to be significantly up-regulated. NKCC-1 showed a tendency toward up-regulation in hyperplastic lungs, while ClC-3 showed a tendency to be down-regulated, but no statistically significant changes could be seen. There was no difference between controls and any of the groups for the expression of ClC-5. CONCLUSION We show that the developmental changes in ClC-2 and ClC-3 protein expression are negatively affected in hypoplastic CDH lungs. Lung hyperplasia created by TO up-regulates the expression of ClC-2. ClC-2 is therefore an interesting potential target in the development of novel, non-invasive, therapies for CDH treatment.
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Affiliation(s)
- Andreas Ringman Uggla
- Research Laboratory Q2:09, Department of Woman and Child Health, Nordic Centre of Excellence for Research in Water Imbalance Related Disorders, Astrid Lindgren Children's Hospital, Karolinska University Hospital, Karolinska Institutet, 171 76 Stockholm, Sweden.
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Hoffmann EK, Lambert IH, Pedersen SF. Physiology of cell volume regulation in vertebrates. Physiol Rev 2009; 89:193-277. [PMID: 19126758 DOI: 10.1152/physrev.00037.2007] [Citation(s) in RCA: 1060] [Impact Index Per Article: 66.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
The ability to control cell volume is pivotal for cell function. Cell volume perturbation elicits a wide array of signaling events, leading to protective (e.g., cytoskeletal rearrangement) and adaptive (e.g., altered expression of osmolyte transporters and heat shock proteins) measures and, in most cases, activation of volume regulatory osmolyte transport. After acute swelling, cell volume is regulated by the process of regulatory volume decrease (RVD), which involves the activation of KCl cotransport and of channels mediating K(+), Cl(-), and taurine efflux. Conversely, after acute shrinkage, cell volume is regulated by the process of regulatory volume increase (RVI), which is mediated primarily by Na(+)/H(+) exchange, Na(+)-K(+)-2Cl(-) cotransport, and Na(+) channels. Here, we review in detail the current knowledge regarding the molecular identity of these transport pathways and their regulation by, e.g., membrane deformation, ionic strength, Ca(2+), protein kinases and phosphatases, cytoskeletal elements, GTP binding proteins, lipid mediators, and reactive oxygen species, upon changes in cell volume. We also discuss the nature of the upstream elements in volume sensing in vertebrate organisms. Importantly, cell volume impacts on a wide array of physiological processes, including transepithelial transport; cell migration, proliferation, and death; and changes in cell volume function as specific signals regulating these processes. A discussion of this issue concludes the review.
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Affiliation(s)
- Else K Hoffmann
- Department of Biology, University of Copenhagen, Copenhagen, Denmark.
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Muir JG, Rose R, Rosella O, Liels K, Barrett JS, Shepherd SJ, Gibson PR. Measurement of short-chain carbohydrates in common Australian vegetables and fruits by high-performance liquid chromatography (HPLC). JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2009; 57:554-65. [PMID: 19123815 DOI: 10.1021/jf802700e] [Citation(s) in RCA: 237] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Fermentable oligo-, di-, and monosaccharides and polyols (FODMAPs) are short-chain carbohydrates that can be poorly absorbed by the small intestine and may have a wide range of effects on gastrointestinal processes. FODMAPs include lactose, fructose in excess of glucose, fructans and fructooligosaccharides (FOS, nystose, kestose), galactooligosaccharides (GOS, raffinose, stachyose), and sugar polyols (sorbitol, mannitol). This paper describes an analytical approach based on HPLC with ELSD that quantifies the major FODMAPs in 45 vegetables and 41 fruits. Sorbitol and/or mannitol were measured in 18 vegetables (range = 0.09-2.96 g/100 g of fw), raffinose and/or stachyose in 7 vegetables (0.08-0.68 g/100 g of fw), and nystose and/or kestose in 19 vegetables (0.02-0.71 g/100 g of fw). Apple, pear, mango, clingstone peach, and watermelon all contained fructose in excess of glucose. Sorbitol was measured in 15 fruits (0.53-5.99 g/100 g of fw), mannitol was found in 2 fruits, and nystose or kestose was measured in 8 fruits. Understanding the importance of dietary FODMAPs will be greatly assisted by comprehensive food composition data.
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Affiliation(s)
- Jane G Muir
- Department of Medicine, Monash University, Box Hill Hospital, Clive Ward Centre, Victoria, Australia.
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Matsuno T, Ito Y, Ohashi T, Morise M, Takeda N, Shimokata K, Imaizumi K, Kume H, Hasegawa Y. Dual pathway activated by tert-butyl hydroperoxide in human airway anion secretion. J Pharmacol Exp Ther 2008; 327:453-64. [PMID: 18664589 DOI: 10.1124/jpet.108.141580] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We analyzed the mechanisms underlying the ion transport induced by tert-butyl hydroperoxide (t-BOOH), a membrane-permeant oxidant that has been widely used as a model of oxidative stress, in human airway epithelial cells (Calu-3). We found that t-BOOH induced a short-circuit current that was composed of two distinct components, a peaked component (PC) and a sustained component (SC). Both components were reduced by the presence of H-89 (N-[2-(4-bromocinnamylamino)ethyl]-5-isoquinoline) [10 microM, a protein kinase A (PKA) inhibitor] and clofilium (100 microM, a cAMP-dependent K+ channel inhibitor) but not by charybdotoxin (50 nM, a human intermediate conductance Ca2+-activated K+ channel inhibitor), suggesting that both PC and SC were generated through a common PKA-dependent/Ca2+-independent pathway. Notwithstanding, analyses of the physiological properties revealed that PC and SC were attributable to different pathways. PC, but not SC, was correlated with apical membrane Cl- conductance and was inhibited by the cyclooxygenase (COX)-2 inhibitor NS-398 (N-[2-(cyclohexyloxyl)-4-nitrophenyl]-methane sulfonamide; 10 microM). In contrast, SC, but not PC, was composed of a component sensitive to bumetanide (50 microM), an inhibitor of the basolateral Na+-K+-2Cl- cotransporter (NKCC1), and was abolished by the cytoskeleton dysfunction induced by cytochalasin D (10 microM) and (R)-(+)-trans-N-(4-pyridyl)-4-(1-aminoethyl)-cyclohexane carboxamide (Y-27632; 20 microM). Collectively, t-BOOH induces PKA-related anion secretion through two independent pathways: rapid activation of apical anion efflux through a COX-2-dependent/cytoskeleton-independent pathway and relatively delayed activation of NKCC1 for basolateral anion uptake through a COX-2-independent/cytoskeleton-dependent pathway.
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Affiliation(s)
- Tadakatsu Matsuno
- Department of Respiratory Medicine, Nagoya University Graduate School of Medicine, Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan.
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NKCC-1 and ENaC are down-regulated in nitrofen-induced hypoplastic lungs with congenital diaphragmatic hernia. Pediatr Surg Int 2008; 24:993-1000. [PMID: 18668250 DOI: 10.1007/s00383-008-2209-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 07/09/2008] [Indexed: 10/21/2022]
Abstract
Congenital diaphragmatic hernia (CDH) is accompanied by pulmonary hypoplasia and pulmonary hypertension. Fetal lung growth is dependent on the secretion of lung liquid, which normally is absorbed at partus. The ion channel NKCC-1 is involved in this secretory process, but has recently also been reported to be implicated in absorption. CDH patients show a disturbed transition from secretion to absorption. alpha- and beta-ENaC are essential for lung liquid absorption. Common for all transcellular ion transport is the need for Na/K-ATPase as a primary driving force. The aim of the study was first to map the normal pulmonary expression of the above proteins during late gestation and secondly to see if the expression was affected in a CDH rat model. Pregnant Sprague-Dawley rat dams were given nitrofen on gestational day 9.5 to induce CDH. The fetuses were removed on gestational days E18 and E21. In addition, newborn rats were harvested postpartum on day P2. The fetuses were put into one of two groups: hypoplastic lungs without CDH (N-CDH) and hypoplastic lungs with CDH (N+CDH). The pulmonary expression of NKCC-1, alpha-/beta-ENaC and Na/K-ATPase was then analyzed using Western blot. We found that the protein levels of NKCC-1 on gestational days E18 and E21 were significantly lower among fetuses with N+CDH as well as N-CDH compared to controls. The expression of beta-ENaC was also significantly down-regulated in both the groups on E18 and E21. The protein levels of alpha-ENaC and Na/K-ATPase were not found to be significantly decreased, but both showed a tendency towards down-regulation. The marked down-regulation of NKCC-1 in fetal hypoplastic lungs with CDH indicates a possibly decreased lung liquid production. This may be one of the mechanisms behind the disturbed pulmonary development in CDH. We also show that beta-ENaC is down-regulated. Down-regulation of beta-ENaC may result in abnormal lung liquid absorption, which could be one of the mechanisms behind the respiratory distress seen in CDH patients postpartum.
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Rocha-González HI, Mao S, Alvarez-Leefmans FJ. Na+,K+,2Cl- cotransport and intracellular chloride regulation in rat primary sensory neurons: thermodynamic and kinetic aspects. J Neurophysiol 2008; 100:169-84. [PMID: 18385481 DOI: 10.1152/jn.01007.2007] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Adult primary afferent neurons are depolarized by GABA throughout their entire surface, including their somata located in dorsal root ganglia (DRG). Primary afferent depolarization (PAD) mediated by GABA released from spinal interneurons determines presynaptic inhibition, a key mechanism in somatosensory processing. The depolarization is due to Cl(-) efflux through GABA(A) channels; the outward Cl(-) gradient is generated by a Na+,K+,2Cl(-) cotransporter (NKCC) as first established in amphibians. Using fluorescence imaging microscopy we measured [Cl(-)]i and cell water volume (CWV) in dissociated rat DRG cells (P0-P21) loaded with N-(ethoxycarbonylmethyl)-6-methoxyquinolinium bromide and calcein, respectively. Basal [Cl(-)]i was 44.2 +/- 1.2 mM (mean +/- SE), Cl(-) equilibrium potential (E Cl) was -27.0 +/- 0.7 mV (n = 75). This [Cl(-)]i is about four times higher than electrochemical equilibrium. On isosmotic removal of external Cl(-), cells lost Cl(-) and shrank. On returning to control solution, cells reaccumulated Cl(-) and recovered CWV. Cl(-) reaccumulation had Na+-dependent (SDC) and Na+-independent (SIC) components. The SIC stabilized at [Cl(-)]i = 13.2 +/- 1.2 mM, suggesting that it was passive (E(Cl) = -60.5 +/- 3 mV). Bumetanide blocked CWV recovery and most (65%) of the SDC (IC50 = 5.7 microM), indicating that both were mediated by NKCC. Active Cl(-) uptake fell with increasing [Cl(-)]i and became negligible when [Cl(-)]i reached basal levels. The kinetics of active Cl(-) uptake suggests a negative feedback system in which intracellular Cl(-)regulates its own influx thereby keeping [Cl(-)]i constant, above electrochemical equilibrium but below the value that would attain if NKCC reached thermodynamic equilibrium.
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Affiliation(s)
- Héctor I Rocha-González
- Department of Pharmacology and Toxicology, Wright State University, Boonshoft School of Medicine, Dayton, Ohio 45435-0001, USA
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Okunola OA, Seganish JL, Salimian KJ, Zavalij PY, Davis JT. Membrane-active calixarenes: toward ‘gating’ transmembrane anion transport. Tetrahedron 2007. [DOI: 10.1016/j.tet.2007.06.124] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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22
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Pieraut S, Laurent-Matha V, Sar C, Hubert T, Méchaly I, Hilaire C, Mersel M, Delpire E, Valmier J, Scamps F. NKCC1 phosphorylation stimulates neurite growth of injured adult sensory neurons. J Neurosci 2007; 27:6751-9. [PMID: 17581962 PMCID: PMC6672700 DOI: 10.1523/jneurosci.1337-07.2007] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Peripheral nerve section promotes regenerative, elongated neuritic growth of adult sensory neurons. Although the role of chloride homeostasis, through the regulation of ionotropic GABA receptors, in the growth status of immature neurons in the CNS begins to emerge, nothing is known of its role in the regenerative growth of injured adult neurons. To analyze the intracellular Cl- variation after a sciatic nerve section in vivo, gramicidin perforated-patch recordings were used to study muscimol-induced currents in mice dorsal root ganglion neurons isolated from control and axotomized neurons. We show that the reversal potential of muscimol-induced current, E(GABA-A), was shifted toward depolarized potentials in axotomized neurons. This was attributable to Cl- influx because removal of extracellular Cl- prevented this shift. Application of bumetanide, an inhibitor of NKCC1 cotransporter and E(GABA-A) recordings in sensory neurons from NKCC1-/- mice, identified NKCC1 as being responsible for the increase in intracellular Cl- in axotomized neurons. In addition, we demonstrate with a phospho-NKCC1 antibody that nerve injury induces an increase in the phosphorylated form of NKCC1 in dorsal root ganglia that could account for intracellular Cl- accumulation. Time-lapse recordings of the neuritic growth of axotomized neurons show a faster growth velocity compared with control. Bumetanide, the intrathecal injection of NKCC1 small interfering RNA, and the use of NKCC1-/- mice demonstrated that NKCC1 is involved in determining the velocity of elongated growth of axotomized neurons. Our results clearly show that NKCC1-induced increase in intracellular chloride concentration is a major event accompanying peripheral nerve regeneration.
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Affiliation(s)
- Simon Pieraut
- Inserm, Unité 583, F-34000 Montpellier, France
- Université Montpellier II, F-34000 Montpellier, France
| | - Valérie Laurent-Matha
- Inserm, Unité 583, F-34000 Montpellier, France
- Université Montpellier II, F-34000 Montpellier, France
| | | | | | - Ilana Méchaly
- Inserm, Unité 583, F-34000 Montpellier, France
- Université Montpellier II, F-34000 Montpellier, France
| | | | | | - Eric Delpire
- Vanderbilt University, Nashville, Tennessee 37235
| | - Jean Valmier
- Inserm, Unité 583, F-34000 Montpellier, France
- Université Montpellier II, F-34000 Montpellier, France
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23
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Gorteau V, Bollot G, Mareda J, Matile S. Rigid-rod anion–π slides for multiion hopping across lipid bilayers. Org Biomol Chem 2007; 5:3000-12. [PMID: 17728867 DOI: 10.1039/b708337h] [Citation(s) in RCA: 148] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Shape-persistent oligo-p-phenylene-N,N-naphthalenediimide (O-NDI) rods are introduced as anion-pi slides for chloride-selective multiion hopping across lipid bilayers. Results from end-group engineering and covalent capture as O-NDI hairpins suggested that self-assembly into transmembrane O-NDI bundles is essential for activity. A halide topology VI (Cl > F > Br approximately I, Cl/Br approximately Cl/I > 7) implied strong anion binding along the anion-pi slides with relatively weak contributions from size exclusion (F >or= OAc). Anomalous mole fraction effects (AMFE) supported the occurrence of multiion hopping along the pi-acidic O-NDI rods. The existence of anion-pi interactions was corroborated by high-level ab initio and DFT calculations. The latter revealed positive NDI quadrupole moments far beyond the hexafluorobenzene standard. Computational studies further suggested that anion binding occurs at the confined, pi-acidic edges of the sticky NDI surface and is influenced by the nature of the phenyl spacer between two NDIs. With regard to methods development, a detailed analysis of the detection of ion selectivity with the HPTS assay including AMFE in vesicles is provided.
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Affiliation(s)
- Virginie Gorteau
- Department of Organic Chemistry, University of Geneva, Geneva, Switzerland
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24
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Abstract
The development of low molecular weight anion transporters is an emerging topic in supramolecular chemistry. The major focus of this tutorial review is on synthetic chloride transport systems that operate in vesicle and cell membranes. The transporters alter transmembrane concentration gradients, and thus they have applications as reagents for cell biology research and as potential chemotherapeutic agents. The molecular designs include monomolecular channels, self-assembled channels and mobile carriers. Also discussed are the experimental assays that measure transport rates across model bilayer membranes.
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Affiliation(s)
- Anthony P. Davis
- School of Chemistry, University of Bristol, Cantock's Close, Bristol, BS8 1TS, UK.
| | - David N. Sheppard
- Department of Physiology, School of Medical Sciences, University of Bristol, University Walk, Bristol, BS8 1TD, UK.
| | - Bradley D. Smith
- Department of Chemistry and Biochemistry and Walther Cancer Research Center, University of Notre Dame, Notre Dame, Indiana 46556, USA.
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25
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Orlov SN, Hamet P. Intracellular monovalent ions as second messengers. J Membr Biol 2006; 210:161-72. [PMID: 16909338 DOI: 10.1007/s00232-006-0857-9] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2005] [Revised: 02/08/2006] [Indexed: 01/03/2023]
Abstract
It is generally accepted that electrochemical gradients of monovalent ions across the plasma membrane, created by the coupled function of pumps, carriers and channels, are involved in the maintenance of resting and action membrane potential, cell volume adjustment, intracellular Ca(2+ )handling and accumulation of glucose, amino acids, nucleotides and other precursors of macromolecular synthesis. In the present review, we summarize data showing that side-by-side with these classic functions, modulation of the intracellular concentration of monovalent ions in a physiologically reasonable range is sufficient to trigger numerous cellular responses, including changes in enzyme activity, gene expression, protein synthesis, cell proliferation and death. Importantly, the engagement of monovalent ions in regulation of the above-listed cellular responses occurs at steps upstream of Ca(2+) (i) and other key intermediates of intracellular signaling, which allows them to be considered as second messengers. With the exception of HCO (3) (-) -sensitive soluble adenylyl cyclase, the molecular origin of sensors involved in the function of monovalent ions as second messengers remains unknown.
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Affiliation(s)
- S N Orlov
- Centre de recherche, Centre hospitalier de l'Université de Montréal, (CHUM)-Hôtel-Dieu, Montreal, Quebec, Canada.
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26
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Winschel CA, Kalidindi A, Zgani I, Magruder JL, Sidorov V. Receptor for Anionic Pyrene Derivatives Provides the Basis for New Biomembrane Assays. J Am Chem Soc 2005; 127:14704-13. [PMID: 16231924 DOI: 10.1021/ja052397i] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
This study describes a new receptor cyclen 1 capable of strong selective binding of pyrene-based anionic dyes under near-physiological conditions. This receptor comprises four naphthylthiourea groups tethered to a cyclen core via an ester linkage. The complexation behavior of cyclen 1 receptor is characterized by a series of (1)H NMR, microcalorimetry, UV-vis, and fluorometry experiments. The relevance of structural features of this receptor to its recognition function is assessed using control compounds that lack some of the groups found in cyclen 1. The specificity of cyclen 1 toward pyrene-based dyes is assessed through experiments using dyes with different molecular organization. The most important finding was the ability of cyclen 1 to bind efficiently to a pH-sensitive dye pyranine, a dye that is commonly used in various biomembrane assays. The high affinity of cyclen 1 to pyranine, its impermeability to the lipid bilayer membrane, fast kinetics of binding, and ability to quench the pyranine's fluorescence were used as a basis for a new membrane leakage assay. This membrane leakage assay is fully compatible with the commonly applied pH-stat transport assay, and therefore it allows for differentiation of the ion transport and nonselective leakage mechanisms within a single set of experiments. The ability of cyclen 1 to quench the fluorescence of pyranine also finds limited applicability to the detection of endovesiculation.
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Affiliation(s)
- Christine A Winschel
- Department of Chemistry, Virginia Commonwealth University, Richmond, Virginia 23284-2006, USA
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27
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Matskevich I, Hegney KL, Flatman PW. Regulation of erythrocyte Na–K–2Cl cotransport by threonine phosphorylation. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2005; 1714:25-34. [PMID: 15996636 DOI: 10.1016/j.bbamem.2005.06.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2004] [Revised: 05/12/2005] [Accepted: 06/06/2005] [Indexed: 10/25/2022]
Abstract
A method is described to measure threonine phosphorylation of the Na-K-2Cl cotransporter in ferret erythrocytes using readily available antibodies. We show that most, if not all, cotransporter in these cells is NKCC1, and this was immunoprecipitated with T4. Cotransport rate, measured as 86Rb influx, correlates well with threonine phosphorylation of T4-immunoprecipitated protein. The cotransporter effects large fluxes and is significantly phosphorylated in cells under control conditions. Transport and phosphorylation increase 2.5- to 3-fold when cells are treated with calyculin A or Na+ arsenite. Both fall to 60% control when cell [Mg2+] is reduced below micromolar or when cells are treated with the kinase inhibitors, 4-amino-5-(4-methylphenyl)-7-(t-butyl)pyrazolo[3,4-d]pyrimidine or staurosporine. Importantly, these latter interventions do not abolish either phosphorylation or transport suggesting that a phosphorylated form of the cotransporter is responsible for residual fluxes. Our experiments suggest protein phosphatase 1 (PrP-1) is extremely active in these cells and dephosphorylates key regulatory threonine residues on the cotransporter. Examination of the effects of kinase inhibition after cells have been treated with high concentrations of calyculin indicates that residual PrP-1 activity is capable of rapidly dephosphorylating the cotransporter. Experiments on cotransporter precipitation with microcystin sepharose suggest that PrP-1 binds to a phosphorylated form of the cotransporter.
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Affiliation(s)
- Ioulia Matskevich
- Membrane Biology Group, College of Medicine and Veterinary Medicine, School of Biomedical and Clinical Laboratory Sciences, The University of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH8 9XD, Scotland, UK
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28
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Marakhova I, Karitskaya I, Aksenov N, Zenin V, Vinogradova T. Interleukin-2-dependent regulation of Na/K pump in human lymphocytes. FEBS Lett 2005; 579:2773-80. [PMID: 15907480 DOI: 10.1016/j.febslet.2005.03.096] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2005] [Revised: 03/04/2005] [Accepted: 03/06/2005] [Indexed: 11/26/2022]
Abstract
The present study provides the first evidence that the abundance of catalytic alpha1-subunit of Na,K-ATPase increases in the course of T cell blast transformation. Immunodepressant cyclosporin A at anti-proliferative doses diminished the induction of alpha1 protein in activated lymphocytes. Furthermore, in competent T cells, IL-2 increases both the transport activity of Na/K pump and the content of Na,K-ATPase alpha1 protein in a time-dependent manner. A correlation was found between the long-term elevation in ouabain-sensitive Rb influxes and the increase in alpha1 protein content in late activated T cells. These results suggest that (1) the increased expression of Na,K-ATPase proteins underlie the cell cycle-dependent upregulation of ion pump during T cell transformation, and (2) IL-2 is involved in the regulated expression of Na,K-ATPase in human lymphocytes.
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29
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Johanson C, McMillan P, Tavares R, Spangenberger A, Duncan J, Silverberg G, Stopa E. Homeostatic capabilities of the choroid plexus epithelium in Alzheimer's disease. Cerebrospinal Fluid Res 2004; 1:3. [PMID: 15679944 PMCID: PMC546405 DOI: 10.1186/1743-8454-1-3] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2004] [Accepted: 12/10/2004] [Indexed: 11/10/2022] Open
Abstract
As the secretory source of vitamins, peptides and hormones for neurons, the choroid plexus (CP) epithelium critically provides substances for brain homeostasis. This distributive process of cerebrospinal fluid (CSF) volume transmission reaches many cellular targets in the CNS. In ageing and ageing-related dementias, the CP-CSF system is less able to regulate brain interstitial fluid. CP primarily generates CSF bulk flow, and so its malfunctioning exacerbates Alzheimers disease (AD). Considerable attention has been devoted to the blood-brain barrier in AD, but more insight is needed on regulatory systems at the human blood-CSF barrier in order to improve epithelial function in severe disease. Using autopsied CP specimens from AD patients, we immunocytochemically examined expression of heat shock proteins (HSP90 and GRP94), fibroblast growth factor receptors (FGFr) and a fluid-regulatory protein (NaK2Cl cotransporter isoform 1 or NKCC1). CP upregulated HSP90, FGFr and NKCC1, even in end-stage AD. These CP adjustments involve growth factors and neuropeptides that help to buffer perturbations in CNS water balance and metabolism. They shed light on CP-CSF system responses to ventriculomegaly and the altered intracranial pressure that occurs in AD and normal pressure hydrocephalus. The ability of injured CP to express key regulatory proteins even at Braak stage V/VI, points to plasticity and function that may be boosted by drug treatment to expedite CSF dynamics. The enhanced expression of human CP 'homeostatic proteins' in AD dementia is discussed in relation to brain deficits and pharmacology.
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Affiliation(s)
- Conrad Johanson
- Department of Clinical Neurosciences, Brown Medical School, Providence, RI 02903, USA
| | - Paul McMillan
- Department of Pathology, Brown Medical School, Providence, RI 02903,USA
| | - Rosemarie Tavares
- Department of Pathology, Brown Medical School, Providence, RI 02903,USA
| | - Anthony Spangenberger
- Department of Clinical Neurosciences, Brown Medical School, Providence, RI 02903, USA
| | - John Duncan
- Department of Clinical Neurosciences, Brown Medical School, Providence, RI 02903, USA
| | - Gerald Silverberg
- Department of Clinical Neurosciences, Brown Medical School, Providence, RI 02903, USA
| | - Edward Stopa
- Department of Clinical Neurosciences, Brown Medical School, Providence, RI 02903, USA
- Department of Pathology, Brown Medical School, Providence, RI 02903,USA
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30
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31
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Jiang G, Akar F, Cobbs SL, Lomashvilli K, Lakkis R, Gordon FJ, Sutliff RL, O'Neill WC. Blood pressure regulates the activity and function of the Na-K-2Cl cotransporter in vascular smooth muscle. Am J Physiol Heart Circ Physiol 2004; 286:H1552-7. [PMID: 15020309 DOI: 10.1152/ajpheart.00695.2003] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The Na-K-2Cl cotransporter (NKCC1) is one of several transporters that have been linked to hypertension, and its inhibition reduces vascular smooth muscle tone and blood pressure. NKCC1 in the rat aorta is stimulated by vasoconstrictors and inhibited by nitrovasodilators, and this is linked to the contractile state of the smooth muscle. To determine whether blood pressure also regulates NKCC1, we examined the acute effect of hypertension on NKCC1 in rats after aortic coarctation. In the hypertensive aorta (28-mmHg rise in mean blood pressure), an increase in NKCC1 activity (measured as bumetanide-sensitive (86)Rb efflux) was apparent by 16 h and reached a plateau of 62% greater than control at 48 h. In contrast, there was a slight decrease in NKCC1 activity in the hypotensive aorta (21% decrease in mean blood pressure). Measurement of NKCC1 mRNA by real-time PCR revealed a fivefold increase in the hypertensive aorta compared with the hypotensive aorta or sham aorta. The inhibition by bumetanide of isometric force response to phenylephrine was significantly greater in the hypertensive aorta than in the control aorta or hypotensive aorta. We conclude that NKCC1 in rat aortic smooth muscle is regulated by blood pressure, most likely through changes in transporter abundance. This upregulation of NKCC1 is associated with a greater contribution to force generation in the hypertensive aorta. This is the first demonstration that NKCC1 in vascular smooth muscle is regulated by blood pressure and indicates that this transporter is important in the acute response of vascular smooth muscle to hypertension.
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Affiliation(s)
- Gengru Jiang
- Department of Medicine, Emory University School of Medicine, Atlanta, GA 30322, USA
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32
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Monteiro I, David ES, Ferraris RP. Ontogenetic development of rat intestinal bile acid transport requires thyroxine but not corticosterone. Pediatr Res 2004; 55:611-21. [PMID: 14711893 DOI: 10.1203/01.pdr.0000112126.07230.9a] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Absorption of bile acids by the distal ileum is an essential component of the enterohepatic circulation. In neonatal rats, the appearance of the apical sodium-dependent bile acid transporter (ASBT) at 17 d of age coincides with increases in serum corticosterone and thyroxine. We tested the hypothesis that these hormones modulate ASBT expression during ileal development. Taurocholate uptake into the isolated ileum of normal 20-d-old pups exhibited saturable (K(m) = 0.52 mM, J(max) = 0.34 pmol mg/min) and nonsaturable (K(diff) = 0.015 min(-1)) components and was two to five times greater than uptake in the proximal intestine. Hypothyroid or euthyroid pups received daily thyroxine injections starting at 6 d of age. At 12 d of age, serum concentrations of thyroxine, ileal abundance of ASBT mRNA, and ileal rates of taurocholate uptake were low in hypothyroid pups that received an injection of vehicle (HT-) or thyroxine (HT+) and in euthyroid pups that received an injection of vehicle (ET-) or thyroxine (ET+). At 20 and 26 d, ileal ASBT mRNA abundance and taurocholate uptake rate remained low in HT- pups but increased dramatically in ET- and ET+ pups, paralleling the increase in serum thyroxine. Restoration of normal plasma thyroxine in HT- pups by thyroxine injections (HT+) restored normal ASBT development. Sodium-glucose co-transporter activity and mRNA expression were independent of serum thyroxine levels. Corticosterone levels were significantly lower in pups that were adrenalectomized at 10 d of age. ASBT mRNA abundance and taurocholate uptake rate increased markedly with age but were the same in adrenalectomized, sham-operated, and nonoperated pups. Hence, endogenous thyroxine but not corticosterone regulates the developmentally timed appearance of ASBT.
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Affiliation(s)
- IonaM Monteiro
- Department of Pediatrics, New Jersey Medical School, 185 S. Orange Avenue, Newark, NJ 07103-2714, USA
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33
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Flatman PW. Regulation of Na-K-2Cl cotransport in red cells. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2004; 559:77-88. [PMID: 18727229 DOI: 10.1007/0-387-23752-6_7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Affiliation(s)
- Peter W Flatman
- Membrane Biology Group, College of Medicine and Veterinary Medicine, The University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, EH8 9XD Scotland, UK.
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34
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Abstract
Mg(2+) efflux from rat erythrocytes was measured in NaCl, NaNO(3), NaSCN and Na gluconate medium. Substitution of extracellular and intracellular Cl(-) with the permeant anions NO(3)(-) and SCN(-) reduced Mg(2+) efflux via Na(+)/Mg(2+) antiport. After substitution of extracellular Cl(-) with the non-permeant anion gluconate, Mg(2+) efflux was not significantly reduced. In Na gluconate medium, an influence of the changed membrane potential and intracellular pH on Mg(2+) efflux could be excluded. The results indicate the existence of Cl(-)-independent Na(+)/Mg(2+) antiport and of Na(+)/Mg(2+) antiport stimulated by intracellular Cl(-). Intracellular Cl(-), as determined by means of (36)Cl(-), was found to stimulate Na(+)/Mg(2+) antiport through a cooperative effect according to a sigmoidal kinetics. The Hill coefficient for intracellular Cl(-) amounted to 1.4-1.8, indicating that two intracellular Cl(-) may be simultaneously active. With respect to specificity, Cl(-) was most effective, followed by Br(-), J(-), and F(-). Stimulation of Na(+)/Mg(2+) antiport by intracellular Cl(-) together with intracellular Mg(2+) may play a role during deoxygenation of erythrocytes and in essential hypertension.
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Affiliation(s)
- H Ebel
- Institut für Klinische Physiologie, Klinikum Benjamin Franklin, Freie Universität Berlin, Hindenburgdamm 30, 12200, Berlin, Germany.
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35
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Jiang G, Cobbs S, Klein JD, O'Neill WC. Aldosterone regulates the Na-K-2Cl cotransporter in vascular smooth muscle. Hypertension 2003; 41:1131-5. [PMID: 12668585 DOI: 10.1161/01.hyp.0000066128.04083.ca] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Aldosterone increases cation transport and contractility of vascular smooth muscle, but the specific transporter involved and how it is linked to smooth muscle tone is unknown. Because the Na-K-2Cl cotransporter (NKCC1) contributes to vascular smooth muscle contraction and is regulated by vasoactive compounds, we sought to determine whether this transporter is a target of aldosterone in rat aorta. Treatment of adrenalectomized rats with aldosterone for 7 days resulted in a 63% increase in NKCC1 activity as measured by bumetanide-sensitive efflux of 86Rb+. Treatment of normal aortas in culture with aldosterone for 3 and 7 days resulted in 29% and 47% increases in NKCC1 activity, respectively. Aldosterone had no acute effect on 86Rb+ efflux. Stimulation of NKCC1 was blocked by spironolactone, a mineralocorticoid receptor antagonist, but not by RU38486, a glucocorticoid receptor antagonist. Aldosterone did not augment the stimulation of NKCC1 by phenylephrine and did not increase NKCC1 mRNA as determined by real-time polymerase chain reaction. We conclude that aldosterone regulates the Na-K-2Cl cotransporter in vascular smooth muscle through classic mineralocorticoid receptors but not through changes in the abundance of NKCC1 mRNA. This could account for the increase in Na+, K+, and Cl- fluxes previously observed in vascular smooth muscle from mineralocorticoid-treated animals and may contribute to increased vascular tone.
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Affiliation(s)
- Gengru Jiang
- Renal Division, Department of Medicine, Emory University School of Medicine, Atlanta, Ga 30322, USA
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36
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Abstract
OBJECTIVE To measure nutrient absorption by the intestine during postnatal development of dogs. ANIMAL 110 Beagles ranging from neonatal to adult dogs. PROCEDURE Rates of absorption for sugars (glucose, galactose, and fructose), amino acids (aspartate, leucine, lysine, methionine, and proline), a dipeptide (glycyl-sarcosine), and linoleic acid by the proximal, mid, and distal regions of the small intestine were measured as functions of age and concentration (kinetics) by use of intact tissues and brush-border membrane vesicles. Absorption of octanoic acid by the proximal portion of the colon was measured in intact tissues. RESULTS Rates of carrier-mediated transport by intact tissues decreased from birth to adulthood for aldohexoses and most amino acids but not for fructose and aspartate. Kinetics and characteristics of absorption suggest that there were changes in the densities, types, and proportions of various carriers for sugars and amino acids. Saturable absorption of linoleic acid in the small intestine and octanoic acid in the proximal portion of the colon increased after weaning. CONCLUSIONS AND CLINICAL RELEVANCE Rates of absorption decreased between birth and adulthood for most nutrients. However, because of intestinal growth, absorption capacities of the entire small intestine remained constant for leucine and proline and increased for glucose, galactose, fructose, aspartate, and proline but were less than predicted from the increase in body weight. Although postnatal ontogeny of nutrient absorption was consistent with changes in the composition of the natural and commercial diets of growing dogs, rates of amino acid and peptide absorption were lower than expected.
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Affiliation(s)
- Randal K Buddington
- Department of Biological Sciences, College of Arts and Science, Mississippi State University, Mississippi State, MS 39762, USA
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37
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Campello S, Tombola F, Cabrini G, Zoratti M. The vacuolating toxin of Helicobacter pylori mimicks the CFTR-mediated chloride conductance. FEBS Lett 2002; 532:237-40. [PMID: 12459497 DOI: 10.1016/s0014-5793(02)03656-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Cystic fibrosis (CF) is caused by defects of the CF transmembrane conductance regulator (CFTR), which acts both as an anion-selective channel and as a regulator of other proteins. The relative contribution of these two functions in CF disease is debated. The toxin VacA forms channels with properties similar to those of the CFTR, and we report here that it can insert into the membrane of various cells originating from respiratory epithelia, generating a chloride conductance comparable to that produced by activation of the CFTR. VacA may therefore become a valuable tool in the study of CF pathogenesis.
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Affiliation(s)
- Silvia Campello
- CNR Institute of Neuroscience, Section for Biomembranes, University of Padova, Viale G. Colombo 3, 35121 Padua, Italy
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38
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Flatman PW. Regulation of Na-K-2Cl cotransport by phosphorylation and protein-protein interactions. BIOCHIMICA ET BIOPHYSICA ACTA 2002; 1566:140-51. [PMID: 12421545 DOI: 10.1016/s0005-2736(02)00586-2] [Citation(s) in RCA: 84] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The Na-K-2Cl cotransporter plays important roles in cell ion homeostasis and volume control and is particularly important in mediating the movement of ions and thus water across epithelia. In addition to being affected by the concentration of the transported ions, cotransport is affected by cell volume, hormones, growth factors, oxygen tension, and intracellular ionized Mg(2+) concentration. These probably influence transport through three main routes acting in parallel: cotransporter phosphorylation, protein-protein interactions and cell Cl(-) concentration. Many effects are mediated, at least in part, by changes in protein phosphorylation, and are disrupted by kinase and phosphatase inhibitors, and manoeuvres that reduce cell ATP content. In some cases, phosphorylation of the cotransporter itself on serine and threonine (but not tyrosine) is associated with changes in transport rate, in others, phosphorylation of associated proteins has more influence. Analysis of the stimulation of cotransport by calyculin A, arsenite and deoxygenation suggests that the cotransporter is phosphorylated by several kinases and dephosphorylated by several phosphatases. These kinases and phosphatases may themselves be regulated by phosphorylation of residues including tyrosine, with Src kinases possibly playing an important role. Protein-protein interactions also influence cotransport activity. Cotransporter molecules bind to each other to form high molecular weight complexes, they also bind to other members of the cation-chloride cotransport family, to a variety of cytoskeletal proteins, and to enzymes that are part of regulatory cascades. Many of these interactions affect transport and may override the effects of cotransporter phosphorylation. Cell Cl(-) may also directly affect the way the cotransporter functions independently of its role as substrate.
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Affiliation(s)
- Peter W Flatman
- Membrane Biology Group, Division of Biomedical and Clinical Laboratory Sciences, The University of Edinburgh, Hugh Robson Building, George Square, Edinburgh Scotland, UK.
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39
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Lytle C, McManus T. Coordinate modulation of Na-K-2Cl cotransport and K-Cl cotransport by cell volume and chloride. Am J Physiol Cell Physiol 2002; 283:C1422-31. [PMID: 12372803 DOI: 10.1152/ajpcell.00130.2002] [Citation(s) in RCA: 84] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Na-K-2Cl cotransporter (NKCC) and K-Cl cotransporter (KCC) play key roles in cell volume regulation and epithelial Cl(-) transport. Reductions in either cell volume or cytosolic Cl(-) concentration ([Cl(-)](i)) stimulate a corrective uptake of KCl and water via NKCC, whereas cell swelling triggers KCl loss via KCC. The dependence of these transporters on volume and [Cl(-)](i) was evaluated in model duck red blood cells. Replacement of [Cl(-)](i) with methanesulfonate elevated the volume set point at which NKCC activates and KCC inactivates. The set point was insensitive to cytosolic ionic strength. Reducing [Cl(-)](i) at a constant driving force for inward NKCC and outward KCC caused the cells to adopt the new set point volume. Phosphopeptide maps of NKCC indicated that activation by cell shrinkage or low [Cl(-)](i) is associated with phosphorylation of a similar constellation of Ser/Thr sites. Like shrinkage, reduction of [Cl(-)](i) accelerated NKCC phosphorylation after abrupt inhibition of the deactivating phosphatase with calyculin A in vivo, whereas [Cl(-)] had no specific effect on dephosphorylation in vitro. Our results indicate that NKCC and KCC are reciprocally regulated by a negative feedback system dually modulated by cell volume and [Cl(-)]. The major effect of Cl(-) on NKCC is exerted through the volume-sensitive kinase that phosphorylates the transport protein.
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Affiliation(s)
- Christian Lytle
- Division of Biomedical Sciences, University of California, Riverside, California 92521, USA.
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