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Giovannuzzi S, Chavarria D, Provensi G, Leri M, Bucciantini M, Carradori S, Bonardi A, Gratteri P, Borges F, Nocentini A, Supuran CT. Dual Inhibitors of Brain Carbonic Anhydrases and Monoamine Oxidase-B Efficiently Protect against Amyloid-β-Induced Neuronal Toxicity, Oxidative Stress, and Mitochondrial Dysfunction. J Med Chem 2024; 67:4170-4193. [PMID: 38436571 DOI: 10.1021/acs.jmedchem.4c00045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/05/2024]
Abstract
We report here the first dual inhibitors of brain carbonic anhydrases (CAs) and monoamine oxidase-B (MAO-B) for the management of Alzheimer's disease. Classical CA inhibitors (CAIs) such as methazolamide prevent amyloid-β-peptide (Aβ)-induced overproduction of reactive oxygen species (ROS) and mitochondrial dysfunction. MAO-B is also implicated in ROS production, cholinergic system disruption, and amyloid plaque formation. In this work, we combined a reversible MAO-B inhibitor of the coumarin and chromone type with benzenesulfonamide fragments as highly effective CAIs. A hit-to-lead optimization led to a significant set of derivatives showing potent low nanomolar inhibition of the target brain CAs (KIs in the range of 0.1-90.0 nM) and MAO-B (IC50 in the range of 6.7-32.6 nM). Computational studies were conducted to elucidate the structure-activity relationship and predict ADMET properties. The most effective multitarget compounds totally prevented Aβ-related toxicity, reverted ROS formation, and restored the mitochondrial functionality in an SH-SY5Y cell model surpassing the efficacy of single-target drugs.
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Affiliation(s)
- Simone Giovannuzzi
- NEUROFARBA Department, Pharmaceutical and Nutraceutical Section, University of Florence, Via U. Schiff 6, Sesto Fiorentino, 50019 Florence, Italy
| | - Daniel Chavarria
- CIQUP-IMS, Department of Chemistry and Biochemistry, Faculty of Sciences, University of Porto, Rua do Campo Alegre s/n, 4169-007 Porto, Portugal
| | - Gustavo Provensi
- NEUROFARBA Department, Section of Pharmacology and Toxicology, University of Florence, via G. Pieraccini 6, 50139 Florence, Italy
| | - Manuela Leri
- Department of Experimental and Clinical Biomedical Sciences "Mario Serio", University of Florence, 50134 Florence, Italy
| | - Monica Bucciantini
- Department of Experimental and Clinical Biomedical Sciences "Mario Serio", University of Florence, 50134 Florence, Italy
| | - Simone Carradori
- Department of Pharmacy, "G. D'Annunzio" University of Chieti and Pescara, via dei Vestini 31, 66100 Chieti, Italy
| | - Alessandro Bonardi
- NEUROFARBA Department, Pharmaceutical and Nutraceutical Section, Laboratory of Molecular Modeling Cheminformatics & QSAR, University of Florence, Via U. Schiff 6, Sesto Fiorentino, 50019 Florence, Italy
| | - Paola Gratteri
- NEUROFARBA Department, Pharmaceutical and Nutraceutical Section, Laboratory of Molecular Modeling Cheminformatics & QSAR, University of Florence, Via U. Schiff 6, Sesto Fiorentino, 50019 Florence, Italy
| | - Fernanda Borges
- CIQUP-IMS, Department of Chemistry and Biochemistry, Faculty of Sciences, University of Porto, Rua do Campo Alegre s/n, 4169-007 Porto, Portugal
| | - Alessio Nocentini
- NEUROFARBA Department, Pharmaceutical and Nutraceutical Section, University of Florence, Via U. Schiff 6, Sesto Fiorentino, 50019 Florence, Italy
| | - Claudiu T Supuran
- NEUROFARBA Department, Pharmaceutical and Nutraceutical Section, University of Florence, Via U. Schiff 6, Sesto Fiorentino, 50019 Florence, Italy
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García-Llorca A, Carta F, Supuran CT, Eysteinsson T. Carbonic anhydrase, its inhibitors and vascular function. Front Mol Biosci 2024; 11:1338528. [PMID: 38348465 PMCID: PMC10859760 DOI: 10.3389/fmolb.2024.1338528] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2023] [Accepted: 01/03/2024] [Indexed: 02/15/2024] Open
Abstract
It has been known for some time that Carbonic Anhydrase (CA, EC 4.2.1.1) plays a complex role in vascular function, and in the regulation of vascular tone. Clinically employed CA inhibitors (CAIs) are used primarily to lower intraocular pressure in glaucoma, and also to affect retinal blood flow and oxygen saturation. CAIs have been shown to dilate vessels and increase blood flow in both the cerebral and ocular vasculature. Similar effects of CAIs on vascular function have been observed in the liver, brain and kidney, while vessels in abdominal muscle and the stomach are unaffected. Most of the studies on the vascular effects of CAIs have been focused on the cerebral and ocular vasculatures, and in particular the retinal vasculature, where vasodilation of its vessels, after intravenous infusion of sulfonamide-based CAIs can be easily observed and measured from the fundus of the eye. The mechanism by which CAIs exert their effects on the vasculature is still unclear, but the classic sulfonamide-based inhibitors have been found to directly dilate isolated vessel segments when applied to the extracellular fluid. Modification of the structure of CAI compounds affects their efficacy and potency as vasodilators. CAIs of the coumarin type, which generally are less effective in inhibiting the catalytically dominant isoform hCA II and unable to accept NO, have comparable vasodilatory effects as the primary sulfonamides on pre-contracted retinal arteriolar vessel segments, providing insights into which CA isoforms are involved. Alterations of the lipophilicity of CAI compounds affect their potency as vasodilators, and CAIs that are membrane impermeant do not act as vasodilators of isolated vessel segments. Experiments with CAIs, that shed light on the role of CA in the regulation of vascular tone of vessels, will be discussed in this review. The role of CA in vascular function will be discussed, with specific emphasis on findings with the effects of CA inhibitors (CAI).
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Affiliation(s)
- Andrea García-Llorca
- Department of Physiology, Faculty of Medicine, University of Iceland, Reykjavik, Iceland
| | - Fabrizio Carta
- NEUROFARBA Department, Section of Pharmaceutical and Nutraceutical Sciences, University of Florence, Florence, Italy
| | - Claudiu T. Supuran
- NEUROFARBA Department, Section of Pharmaceutical and Nutraceutical Sciences, University of Florence, Florence, Italy
| | - Thor Eysteinsson
- Department of Physiology, Faculty of Medicine, University of Iceland, Reykjavik, Iceland
- Department of Ophthalmology, Faculty of Medicine, University of Iceland, Reykjavik, Iceland
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Cuffaro D, Di Leo R, Ciccone L, Nocentini A, Supuran CT, Nuti E, Rossello A. New isoxazolidinyl-based N-alkylethanolamines as new activators of human brain carbonic anhydrases. J Enzyme Inhib Med Chem 2023; 38:2164574. [PMID: 36630083 PMCID: PMC9848372 DOI: 10.1080/14756366.2022.2164574] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Carbonic anhydrases (CAs) are widespread metalloenzymes which catalyse the reversible hydration of carbon dioxide (CO2) to bicarbonate (HCO3-) and a proton, relevant in many physiological processes. In the last few years, the involvement of CA activation in different metabolic pathways in the human brain addressed the research to the discovery of novel CA activators. Here, a new series of isoxazoline-based amino alcohols as CA activators was investigated. The synthesis and the CA activating effects towards four human CA isoforms expressed in the human brain, that are hCAs I, II, IV and VII, were reported. The best results were obtained for the (methyl)-isoxazoline-amino alcohols 3 and 5 with KA values in the submicromolar range (0.52-0.86 µM) towards hCA VII, and a good selectivity over hCA I. Being hCA VII involved in brain function and metabolism, the newly identified CA activators might be promising hit compounds with potential therapeutic applications in ageing, epilepsy or neurodegeneration.
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Affiliation(s)
| | | | - Lidia Ciccone
- Department of Pharmacy, University of Pisa, Pisa, Italy
| | - Alessio Nocentini
- Department of Neurofarba, University of Florence, Sesto Fiorentino, Italy,CONTACT Alessio Nocentini Physical address Department of Neurofarba, University of Florence, Sesto Fiorentino, Italy
| | - Claudiu T. Supuran
- Department of Neurofarba, University of Florence, Sesto Fiorentino, Italy
| | - Elisa Nuti
- Department of Pharmacy, University of Pisa, Pisa, Italy,Elisa Nuti Physical address Department of Pharmacy, University of Pisa, Pisa, Italy
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4
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Cheng K, Wang Y, He Y, Tian Y, Li J, Chen C, Xu X, Wu Z, Yu H, Chen X, Wu Y, Song W, Dong Z, Xu H, Xie P. Upregulation of carbonic anhydrase 1 beneficial for depressive disorder. Acta Neuropathol Commun 2023; 11:59. [PMID: 37013604 PMCID: PMC10071615 DOI: 10.1186/s40478-023-01545-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Accepted: 03/06/2023] [Indexed: 04/05/2023] Open
Abstract
Carbonic Anhydrase 1 (CAR1) is a zinc-metalloenzyme that catalyzes the hydration of carbon dioxide, and the alteration of CAR1 has been implicated in neuropsychiatric disorders. However, the mechanism underlying the role of CAR1 in major depressive disorder (MDD) remains largely unknown. In this study, we report the decreased level of CAR1 in MDD patients and depression-like model rodents. We found that CAR1 is expressed in hippocampal astrocytes and CAR1 regulates extracellular bicarbonate concentration and pH value in the partial hilus. Ablation of the CAR1 gene increased the activity of granule cells via decreasing their miniature inhibitory postsynaptic currents (mIPSC), and caused depression-like behaviors in CAR1-knockout mice. Astrocytic CAR1 expression rescued the deficits in mIPSCs of granule cells and reduced depression-like behaviors in CAR1 deficient mice. Furthermore, pharmacological activation of CAR1 and overexpression of CAR1 in the ventral hippocampus of mice improved depressive behaviors. These findings uncover a critical role of CAR1 in the MDD pathogenesis and its therapeutic potential.
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Affiliation(s)
- Ke Cheng
- NHC Key Laboratory of Diagnosis and Treatment on Brain Functional Diseases, The First Affiliated Hospital of Chongqing Medical University, Chongqing, 400016, China
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, 200031, China
| | - Yue Wang
- NHC Key Laboratory of Diagnosis and Treatment on Brain Functional Diseases, The First Affiliated Hospital of Chongqing Medical University, Chongqing, 400016, China
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, 200031, China
| | - Yong He
- NHC Key Laboratory of Diagnosis and Treatment on Brain Functional Diseases, The First Affiliated Hospital of Chongqing Medical University, Chongqing, 400016, China
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, 400016, China
| | - Yu Tian
- NHC Key Laboratory of Diagnosis and Treatment on Brain Functional Diseases, The First Affiliated Hospital of Chongqing Medical University, Chongqing, 400016, China
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, 400016, China
| | - Junjie Li
- Ministry of Education Key Laboratory of Child Development and Disorders, National Clinical Research Center for Child Health and Disorders, Chongqing, 400014, China
- Chongqing Key Laboratory of Translational Medical Research in Cognitive Development and Learning and Memory Disorders, Children's Hospital of Chongqing Medical University, Chongqing, 400014, China
| | - Chong Chen
- NHC Key Laboratory of Diagnosis and Treatment on Brain Functional Diseases, The First Affiliated Hospital of Chongqing Medical University, Chongqing, 400016, China
| | - Xingzhe Xu
- NHC Key Laboratory of Diagnosis and Treatment on Brain Functional Diseases, The First Affiliated Hospital of Chongqing Medical University, Chongqing, 400016, China
| | - Zhonghao Wu
- NHC Key Laboratory of Diagnosis and Treatment on Brain Functional Diseases, The First Affiliated Hospital of Chongqing Medical University, Chongqing, 400016, China
| | - Heming Yu
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, 400016, China
| | - Xiangyu Chen
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, 400016, China
| | - Yili Wu
- Oujiang Laboratory (Zhejiang Lab for Regenerative Medicine, Vision and Brain Health), Institute of Aging, Zhejiang Provincial Clinical Research Center for Mental Disorders, Key Laboratory of Alzheimer's Disease of Zhejiang Province, School of Mental Health and Kangning Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, 325000, China
| | - Weihong Song
- Oujiang Laboratory (Zhejiang Lab for Regenerative Medicine, Vision and Brain Health), Institute of Aging, Zhejiang Provincial Clinical Research Center for Mental Disorders, Key Laboratory of Alzheimer's Disease of Zhejiang Province, School of Mental Health and Kangning Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, 325000, China.
| | - Zhifang Dong
- Ministry of Education Key Laboratory of Child Development and Disorders, National Clinical Research Center for Child Health and Disorders, Chongqing, 400014, China.
- Chongqing Key Laboratory of Translational Medical Research in Cognitive Development and Learning and Memory Disorders, Children's Hospital of Chongqing Medical University, Chongqing, 400014, China.
| | - Huatai Xu
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, 200031, China.
- Shanghai Center for Brain Science and Brain-Inspired Intelligence Technology, Shanghai, 201210, China.
| | - Peng Xie
- NHC Key Laboratory of Diagnosis and Treatment on Brain Functional Diseases, The First Affiliated Hospital of Chongqing Medical University, Chongqing, 400016, China.
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, 400016, China.
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Gupta SC, Ghobbeh A, Taugher-Hebl RJ, Fan R, Hardie JB, LaLumiere RT, Wemmie JA. Carbonic anhydrase 4 disruption decreases synaptic and behavioral adaptations induced by cocaine withdrawal. SCIENCE ADVANCES 2022; 8:eabq5058. [PMID: 36383659 PMCID: PMC9668291 DOI: 10.1126/sciadv.abq5058] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Accepted: 09/22/2022] [Indexed: 06/16/2023]
Abstract
Cocaine use followed by withdrawal induces synaptic changes in nucleus accumbens (NAc), which are thought to underlie subsequent drug-seeking behaviors and relapse. Previous studies suggest that cocaine-induced synaptic changes depend on acid-sensing ion channels (ASICs). Here, we investigated potential involvement of carbonic anhydrase 4 (CA4), an extracellular pH-buffering enzyme. We examined effects of CA4 in mice on ASIC-mediated synaptic transmission in medium spiny neurons (MSNs) in NAc, as well as on cocaine-induced synaptic changes and behavior. We found that CA4 is expressed in the NAc and present in synaptosomes. Disrupting CA4 either globally, or locally, increased ASIC-mediated synaptic currents in NAc MSNs and protected against cocaine withdrawal-induced changes in synapses and cocaine-seeking behavior. These findings raise the possibility that CA4 might be a previously unidentified therapeutic target for addiction and relapse.
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Affiliation(s)
- Subhash C. Gupta
- Department of Psychiatry, University of Iowa, Iowa City, IA, USA
- Department of Veterans Affairs Medical Center, Iowa City, IA, USA
| | - Ali Ghobbeh
- Department of Psychiatry, University of Iowa, Iowa City, IA, USA
- Department of Veterans Affairs Medical Center, Iowa City, IA, USA
| | - Rebecca J. Taugher-Hebl
- Department of Psychiatry, University of Iowa, Iowa City, IA, USA
- Department of Veterans Affairs Medical Center, Iowa City, IA, USA
| | - Rong Fan
- Department of Psychiatry, University of Iowa, Iowa City, IA, USA
- Department of Veterans Affairs Medical Center, Iowa City, IA, USA
| | - Jason B. Hardie
- Department of Psychiatry, University of Iowa, Iowa City, IA, USA
- Department of Veterans Affairs Medical Center, Iowa City, IA, USA
| | - Ryan T. LaLumiere
- Department of Psychological and Brain Sciences, University of Iowa, Iowa City, IA, USA
- Iowa Neuroscience Institute, University of Iowa, Iowa City, IA, USA
- Interdisciplinary Graduate Program in Neuroscience, University of Iowa, Iowa City, IA, USA
| | - John A. Wemmie
- Department of Psychiatry, University of Iowa, Iowa City, IA, USA
- Department of Veterans Affairs Medical Center, Iowa City, IA, USA
- Iowa Neuroscience Institute, University of Iowa, Iowa City, IA, USA
- Interdisciplinary Graduate Program in Neuroscience, University of Iowa, Iowa City, IA, USA
- Department of Molecular Physiology and Biophysics, University of Iowa, Iowa City, IA, USA
- Medical Scientist Training Program, University of Iowa, Iowa City, IA, USA
- Department of Neurosurgery, University of Iowa, Iowa City, IA, USA
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6
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Ma J, Gao X, Li Y, DeCoursey TE, Shull GE, Wang HS. The HVCN1 voltage-gated proton channel contributes to pH regulation in canine ventricular myocytes. J Physiol 2022; 600:2089-2103. [PMID: 35244217 PMCID: PMC9058222 DOI: 10.1113/jp282126] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Accepted: 02/24/2022] [Indexed: 11/09/2022] Open
Abstract
KEY POINTS Intracellular pH (pHi ) regulation is crucial for cardiac function, as acidification depresses contractility and causes arrhythmias. H+ ions are generated in cardiomyocytes from metabolic processes and particularly from CO2 hydration, which has been shown to facilitate CO2 -venting from mitochondria. Currently, the NHE1 Na+ /H+ exchanger is viewed as the dominant H+ -extrusion mechanism in cardiac muscle. We show that the HVCN1 voltage-gated proton channel is present and functional in canine ventricular myocytes, and that HVCN1 and NHE1 both contribute to pHi regulation. HVCN1 provides an energetically-efficient mechanism of H+ -extrusion that would not cause Na+ -loading, which can cause pathology, and that could contribute to transport-mediated CO2 disposal. These results provide a major advance in our understanding of pHi regulation in cardiac muscle. ABSTRACT Regulation of intracellular pH (pHi ) in cardiomyocytes is crucial for cardiac function; however, currently known mechanisms for direct or indirect extrusion of acid from cardiomyocytes seem insufficient for energetically-efficient extrusion of the massive H+ loads generated under in vivo conditions. In cardiomyocytes, voltage-sensitive H+ channel activity mediated by the HVCN1 proton channel would be a highly efficient means of disposing of H+ , while avoiding Na+ -loading, as occurs during direct acid extrusion via Na+ /H+ exchange or indirect acid extrusion via Na+ -HCO3 - cotransport. PCR and immunoblotting demonstrated expression of HVCN1 mRNA and protein in canine heart. Patch clamp analysis of canine ventricular myocytes revealed a voltage-gated H+ current that was highly H+ -selective. The current was blocked by external Zn2+ and the HVCN1 blocker 5-chloro-2-guanidinobenzimidazole (ClGBI). Both the gating and Zn2+ blockade of the current were strongly influenced by the pH gradient across the membrane. All characteristics of the observed current were consistent with the known hallmarks of HVCN1-mediated H+ current. Inhibition of HVCN1 and the NHE1 Na+ /H+ exchanger, singly and in combination, showed that either mechanism is largely sufficient to maintain pHi in beating cardiomyocytes, but that inhibition of both activities causes rapid acidification. These results show that HVCN1 is expressed in canine ventricular myocytes and provides a major H+ -extrusion activity, with a capacity similar to that of NHE1. In the beating heart in vivo, this activity would allow Na+ -independent extrusion of H+ during each action potential and, when functionally coupled with anion transport mechanisms, could facilitate transport-mediated CO2 disposal. Abstract figure legend The HVCN1 proton channel is expressed in canine ventricular myocytes and contributes to H+ extrusion. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Jianyong Ma
- Department of Pharmacology and Systems Physiology, University of Cincinnati College of Medicine, Cincinnati, Ohio, 45267, USA
| | - Xiaoqian Gao
- Department of Pharmacology and Systems Physiology, University of Cincinnati College of Medicine, Cincinnati, Ohio, 45267, USA
| | - Yutian Li
- Department of Pharmacology and Systems Physiology, University of Cincinnati College of Medicine, Cincinnati, Ohio, 45267, USA
| | - Thomas E DeCoursey
- Department of Physiology & Biophysics, Rush University, Chicago, Illinois, 60612, USA
| | - Gary E Shull
- Department of Molecular Genetics, Biochemistry and Microbiology, University of Cincinnati College of Medicine, Cincinnati, Ohio, 45267, USA
| | - Hong-Sheng Wang
- Department of Pharmacology and Systems Physiology, University of Cincinnati College of Medicine, Cincinnati, Ohio, 45267, USA
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Lee A, Mason ML, Lin T, Kumar SB, Kowdley D, Leung JH, Muhanna D, Sun Y, Ortega-Anaya J, Yu L, Fitzgerald J, DeVries AC, Nelson RJ, Weil ZM, Jiménez-Flores R, Parquette JR, Ziouzenkova O. Amino Acid Nanofibers Improve Glycemia and Confer Cognitive Therapeutic Efficacy to Bound Insulin. Pharmaceutics 2021; 14:pharmaceutics14010081. [PMID: 35056977 PMCID: PMC8778970 DOI: 10.3390/pharmaceutics14010081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Revised: 12/19/2021] [Accepted: 12/23/2021] [Indexed: 12/04/2022] Open
Abstract
Diabetes poses a high risk for debilitating complications in neural tissues, regulating glucose uptake through insulin-dependent and predominantly insulin-independent pathways. Supramolecular nanostructures provide a flexible strategy for combinatorial regulation of glycemia. Here, we compare the effects of free insulin to insulin bound to positively charged nanofibers comprised of self-assembling amino acid compounds (AACs) with an antioxidant-modified side chain moiety (AAC2) in both in vitro and in vivo models of type 1 diabetes. Free AAC2, free human insulin (hINS) and AAC2-bound-human insulin (AAC2-hINS) were tested in streptozotocin (STZ)-induced mouse model of type 1 diabetes. AAC2-hINS acted as a complex and exhibited different properties compared to free AAC2 or hINS. Mice treated with the AAC2-hINS complex were devoid of hypoglycemic episodes, had improved levels of insulin in circulation and in the brain, and increased expression of neurotransmitter taurine transporter, Slc6a6. Consequently, treatment with AAC2-hINS markedly advanced both physical and cognitive performance in mice with STZ-induced and genetic type 1 diabetes compared to treatments with free AAC2 or hINS. This study demonstrates that the flexible nanofiber AAC2 can serve as a therapeutic platform for the combinatorial treatment of diabetes and its complications.
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Affiliation(s)
- Aejin Lee
- Department of Human Sciences, The Ohio State University, Columbus, OH 43210, USA; (A.L.); (S.B.K.); (D.K.); (J.H.L.); (D.M.)
| | - McKensie L. Mason
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA; (M.L.M.); (T.L.); (Y.S.); (J.R.P.)
| | - Tao Lin
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA; (M.L.M.); (T.L.); (Y.S.); (J.R.P.)
| | - Shashi Bhushan Kumar
- Department of Human Sciences, The Ohio State University, Columbus, OH 43210, USA; (A.L.); (S.B.K.); (D.K.); (J.H.L.); (D.M.)
| | - Devan Kowdley
- Department of Human Sciences, The Ohio State University, Columbus, OH 43210, USA; (A.L.); (S.B.K.); (D.K.); (J.H.L.); (D.M.)
| | - Jacob H. Leung
- Department of Human Sciences, The Ohio State University, Columbus, OH 43210, USA; (A.L.); (S.B.K.); (D.K.); (J.H.L.); (D.M.)
| | - Danah Muhanna
- Department of Human Sciences, The Ohio State University, Columbus, OH 43210, USA; (A.L.); (S.B.K.); (D.K.); (J.H.L.); (D.M.)
| | - Yuan Sun
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA; (M.L.M.); (T.L.); (Y.S.); (J.R.P.)
| | - Joana Ortega-Anaya
- Department of Food Science and Technology, The Ohio State University, Columbus, OH 43210, USA; (J.O.-A.); (R.J.-F.)
| | - Lianbo Yu
- Department of Biomedical Informatics, The Ohio State University, Columbus, OH 43210, USA;
| | - Julie Fitzgerald
- Department of Neuroscience, The Ohio State University, Columbus, OH 43210, USA; (J.F.); (A.C.D.); (Z.M.W.)
| | - A. Courtney DeVries
- Department of Neuroscience, The Ohio State University, Columbus, OH 43210, USA; (J.F.); (A.C.D.); (Z.M.W.)
- Department of Neuroscience, West Virginia University, Morgantown, WV 26506, USA
| | - Randy J. Nelson
- Rockefeller Neuroscience Institute, West Virginia University, Morgantown, WV 26506, USA;
| | - Zachary M. Weil
- Department of Neuroscience, The Ohio State University, Columbus, OH 43210, USA; (J.F.); (A.C.D.); (Z.M.W.)
| | - Rafael Jiménez-Flores
- Department of Food Science and Technology, The Ohio State University, Columbus, OH 43210, USA; (J.O.-A.); (R.J.-F.)
| | - Jon R. Parquette
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA; (M.L.M.); (T.L.); (Y.S.); (J.R.P.)
| | - Ouliana Ziouzenkova
- Department of Human Sciences, The Ohio State University, Columbus, OH 43210, USA; (A.L.); (S.B.K.); (D.K.); (J.H.L.); (D.M.)
- Correspondence: ; Tel.: +1-614-292-5034
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Barresi E, Ravichandran R, Germelli L, Angeli A, Baglini E, Salerno S, Marini AM, Costa B, Da Pozzo E, Martini C, Da Settimo F, Supuran C, Cosconati S, Taliani S. Carbonic anhydrase activation profile of indole-based derivatives. J Enzyme Inhib Med Chem 2021; 36:1783-1797. [PMID: 34340630 PMCID: PMC8344252 DOI: 10.1080/14756366.2021.1959573] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Carbonic Anhydrase Activators (CAAs) could represent a novel approach for the treatment of Alzheimer’s disease, ageing, and other conditions that require remedial achievement of spatial learning and memory therapy. Within a research project aimed at developing novel CAAs selective for certain isoforms, three series of indole-based derivatives were investigated. Enzyme activation assay on human CA I, II, VA, and VII isoforms revealed several effective micromolar activators, with promising selectivity profiles towards the brain-associated cytosolic isoform hCA VII. Molecular modelling studies suggested a theoretical model of the complex between hCA VII and the new activators and provide a possible explanation for their modulating as well as selectivity properties. Preliminary biological evaluations demonstrated that one of the most potent CAA 7 is not cytotoxic and is able to increase the release of the brain-derived neurotrophic factor (BDNF) from human microglial cells, highlighting its possible application in the treatment of CNS-related disorders.
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Affiliation(s)
| | | | | | - Andrea Angeli
- Department of NEUROFARBA, Section of Pharmaceutical and Nutraceutical Sciences, University of Florence, Firenze, Sesto Fiorentino, Italy
| | - Emma Baglini
- Department of Pharmacy, University of Pisa, Pisa, Italy
| | | | | | - Barbara Costa
- Department of Pharmacy, University of Pisa, Pisa, Italy
| | | | | | | | - Claudiu Supuran
- Department of NEUROFARBA, Section of Pharmaceutical and Nutraceutical Sciences, University of Florence, Firenze, Sesto Fiorentino, Italy
| | - Sandro Cosconati
- DiSTABiF, University of Campania Luigi Vanvitelli, Caserta, Italy
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9
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Nocentini A, Cuffaro D, Ciccone L, Orlandini E, Nencetti S, Nuti E, Rossello A, Supuran CT. Activation of carbonic anhydrases from human brain by amino alcohol oxime ethers: towards human carbonic anhydrase VII selective activators. J Enzyme Inhib Med Chem 2021; 36:48-57. [PMID: 33103482 PMCID: PMC7594847 DOI: 10.1080/14756366.2020.1838501] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
The synthesis and carbonic anhydrase (CA; EC 4.2.1.1) activating effects of a series of oxime ether-based amino alcohols towards four human (h) CA isoforms expressed in human brain, hCA I, II, IV and VII, are described. Most investigated amino alcohol derivatives induced a consistent activation of the tested CAs, with KAs spanning from a low micromolar to a medium nanomolar range. Specifically, hCA II and VII, putative main CA targets when central nervous system (CNS) diseases are concerned, were most efficiently activated by these oxime ether derivatives. Furthermore, a multitude of selective hCA VII activators were identified. As hCA VII is one of the key isoforms involved in brain metabolism and other brain functions, the identified potent and selective hCA VII activators may be considered of interest for investigations of various therapeutic applications or as lead compounds in search of even more potent and selective CA activators.
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Affiliation(s)
- Alessio Nocentini
- Section of Pharmaceutical and Nutraceutical Sciences, Department of Neuroscience, Psychology, Drug Research and Child's Health (Neurofarba), University of Florence, Sesto Fiorentino, Italy
| | | | - Lidia Ciccone
- Department of Pharmacy, University of Pisa, Pisa, Italy
| | | | | | - Elisa Nuti
- Department of Pharmacy, University of Pisa, Pisa, Italy
| | | | - Claudiu T Supuran
- Section of Pharmaceutical and Nutraceutical Sciences, Department of Neuroscience, Psychology, Drug Research and Child's Health (Neurofarba), University of Florence, Sesto Fiorentino, Italy
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10
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Bonnet U, Wiemann M. Topiramate Decelerates Bicarbonate-Driven Acid-Elimination of Human Neocortical Neurons: Strategic Significance for its Antiepileptic, Antimigraine and Neuroprotective Properties. CNS & NEUROLOGICAL DISORDERS-DRUG TARGETS 2020; 19:264-275. [PMID: 32496992 DOI: 10.2174/1871527319666200604173208] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2019] [Revised: 04/08/2020] [Accepted: 04/09/2020] [Indexed: 12/27/2022]
Abstract
BACKGROUND Mammalian central neurons regulate their intracellular pH (pHi) strongly and even slight pHi-fluctuations can influence inter-/intracellular signaling, synaptic plasticity and excitability. OBJECTIVE For the first time, we investigated topiramate´s (TPM) influence on pHi-behavior of human central neurons representing a promising target for anticonvulsants and antimigraine drugs. METHODS In slice-preparations of tissue resected from the middle temporal gyrus of five adults with intractable temporal lobe epilepsy, BCECF-AM-loaded neocortical pyramidal-cells were investigated by fluorometry. The pHi-regulation was estimated by using the recovery-slope from intracellular acidification after an Ammonium-Prepulse (APP). RESULTS Among 17 pyramidal neurons exposed to 50 μM TPM, seven (41.24%) responded with an altered resting-pHi (7.02±0.12), i.e., acidification of 0.01-0.03 pH-units. The more alkaline the neurons, the greater the TPM-related acidifications (r=0.7, p=0.001, n=17). The recovery from APPacidification was significantly slowed under TPM (p<0.001, n=5). Further experiments using nominal bicarbonate-free (n=2) and chloride-free (n=2) conditions pointed to a modulation of the HCO3 -- driven pHi-regulation by TPM, favoring a stimulation of the passive Cl-/HCO3 --antiporter (CBT) - an acid-loader predominantly in more alkaline neurons. CONCLUSION TPM modulated the bicarbonate-driven pHi-regulation, just as previously described in adult guinea-pig hippocampal neurons. We discussed the significance of the resulting subtle acidifications for beneficial antiepileptic, antimigraine and neuroprotective effects as well as for unwanted cognitive deficits.
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Affiliation(s)
- Udo Bonnet
- Department of Psychiatry, Psychotherapy, and Psychosomatic Medicine, Evangelisches Krankenhaus Castrop-Rauxel, Academic Teaching Hospital of the University Duisburg-Essen, Castrop-Rauxel, Germany.,Department of Psychiatry and Psychotherapy, Faculty of Medicine, LVR-Hospital Essen, University of Duisburg-Essen, Essen, Germany
| | - Martin Wiemann
- Institute of Physiology, University of Duisburg-Essen, Essen, Germany.,IBE R&D gGmbH, Institute for Lung Health, D-48149 Munster, Germany
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11
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Becker HM, Deitmer JW. Transport Metabolons and Acid/Base Balance in Tumor Cells. Cancers (Basel) 2020; 12:cancers12040899. [PMID: 32272695 PMCID: PMC7226098 DOI: 10.3390/cancers12040899] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Revised: 04/03/2020] [Accepted: 04/04/2020] [Indexed: 02/07/2023] Open
Abstract
Solid tumors are metabolically highly active tissues, which produce large amounts of acid. The acid/base balance in tumor cells is regulated by the concerted interplay between a variety of membrane transporters and carbonic anhydrases (CAs), which cooperate to produce an alkaline intracellular, and an acidic extracellular, environment, in which cancer cells can outcompete their adjacent host cells. Many acid/base transporters form a structural and functional complex with CAs, coined "transport metabolon". Transport metabolons with bicarbonate transporters require the binding of CA to the transporter and CA enzymatic activity. In cancer cells, these bicarbonate transport metabolons have been attributed a role in pH regulation and cell migration. Another type of transport metabolon is formed between CAs and monocarboxylate transporters, which mediate proton-coupled lactate transport across the cell membrane. In this complex, CAs function as "proton antenna" for the transporter, which mediate the rapid exchange of protons between the transporter and the surroundings. These transport metabolons do not require CA catalytic activity, and support the rapid efflux of lactate and protons from hypoxic cancer cells to allow sustained glycolytic activity and cell proliferation. Due to their prominent role in tumor acid/base regulation and metabolism, transport metabolons might be promising drug targets for new approaches in cancer therapy.
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Affiliation(s)
- Holger M. Becker
- Institute of Physiological Chemistry, University of Veterinary Medicine Hannover, D-30559 Hannover, Germany
- Correspondence:
| | - Joachim W. Deitmer
- Department of Biology, University of Kaiserslautern, D-67653 Kaiserslautern, Germany;
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12
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Lee D, Hong JH. The Fundamental Role of Bicarbonate Transporters and Associated Carbonic Anhydrase Enzymes in Maintaining Ion and pH Homeostasis in Non-Secretory Organs. Int J Mol Sci 2020; 21:ijms21010339. [PMID: 31947992 PMCID: PMC6981687 DOI: 10.3390/ijms21010339] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Revised: 01/02/2020] [Accepted: 01/03/2020] [Indexed: 12/18/2022] Open
Abstract
The bicarbonate ion has a fundamental role in vital systems. Impaired bicarbonate transport leads to various diseases, including immune disorders, cystic fibrosis, tumorigenesis, kidney diseases, brain dysfunction, tooth fracture, ischemic reperfusion injury, hypertension, impaired reproductive system, and systemic acidosis. Carbonic anhydrases are involved in the mechanism of bicarbonate movement and consist of complex of bicarbonate transport systems including bicarbonate transporters. This review focused on the convergent regulation of ion homeostasis through various ion transporters including bicarbonate transporters, their regulatory enzymes, such as carbonic anhydrases, pH regulatory role, and the expression pattern of ion transporters in non-secretory systems throughout the body. Understanding the correlation between these systems will be helpful in order to obtain new insights and design potential therapeutic strategies for the treatment of pH-related disorders. In this review, we have discussed the broad prospects and challenges that remain in elucidation of bicarbonate-transport-related biological and developmental systems.
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Affiliation(s)
| | - Jeong Hee Hong
- Correspondence: ; Tel.: +82-32-899-6682; Fax: +82-32-899-6039
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13
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Becker HM. Carbonic anhydrase IX and acid transport in cancer. Br J Cancer 2020; 122:157-167. [PMID: 31819195 PMCID: PMC7051959 DOI: 10.1038/s41416-019-0642-z] [Citation(s) in RCA: 99] [Impact Index Per Article: 24.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Revised: 08/29/2019] [Accepted: 10/22/2019] [Indexed: 02/07/2023] Open
Abstract
Alterations in tumour metabolism and acid/base regulation result in the formation of a hostile environment, which fosters tumour growth and metastasis. Acid/base homoeostasis in cancer cells is governed by the concerted interplay between carbonic anhydrases (CAs) and various transport proteins, which either mediate proton extrusion or the shuttling of acid/base equivalents, such as bicarbonate and lactate, across the cell membrane. Accumulating evidence suggests that some of these transporters interact both directly and functionally with CAIX to form a protein complex coined the 'transport metabolon'. Transport metabolons formed between bicarbonate transporters and CAIX require CA catalytic activity and have a function in cancer cell migration and invasion. Another type of transport metabolon is formed by CAIX and monocarboxylate transporters. In this complex, CAIX functions as a proton antenna for the transporter, which drives the export of lactate and protons from the cell. Since CAIX is almost exclusively expressed in cancer cells, these transport metabolons might serve as promising targets to interfere with tumour pH regulation and energy metabolism. This review provides an overview of the current state of research on the function of CAIX in tumour acid/base transport and discusses how CAIX transport metabolons could be exploited in modern cancer therapy.
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Affiliation(s)
- Holger M Becker
- Institute of Physiological Chemistry, University of Veterinary Medicine Hannover, D-30559, Hannover, Germany.
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14
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Deitmer JW, Theparambil SM, Ruminot I, Noor SI, Becker HM. Energy Dynamics in the Brain: Contributions of Astrocytes to Metabolism and pH Homeostasis. Front Neurosci 2019; 13:1301. [PMID: 31866811 PMCID: PMC6909239 DOI: 10.3389/fnins.2019.01301] [Citation(s) in RCA: 70] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Accepted: 11/20/2019] [Indexed: 12/17/2022] Open
Abstract
Regulation of metabolism is complex and involves enzymes and membrane transporters, which form networks to support energy dynamics. Lactate, as a metabolic intermediate from glucose or glycogen breakdown, appears to play a major role as additional energetic substrate, which is shuttled between glycolytic and oxidative cells, both under hypoxic and normoxic conditions. Transport of lactate across the cell membrane is mediated by monocarboxylate transporters (MCTs) in cotransport with H+, which is a substrate, a signal and a modulator of metabolic processes. MCTs form a “transport metabolon” with carbonic anhydrases (CAs), which not only provide a rapid equilibrium between CO2, HCO3– and H+, but, in addition, enhances lactate transport, as found in Xenopus oocytes, employed as heterologous expression system, as well as in astrocytes and cancer cells. Functional interactions between different CA isoforms and MCTs have been found to be isoform-specific, independent of the enzyme’s catalytic activity, and they require physical interaction between the proteins. CAs mediate between different states of metabolic acidosis, induced by glycolysis and oxidative phosphorylation, and play a relay function in coupling pH regulation and metabolism. In the brain, metabolic processes in astrocytes appear to be linked to bicarbonate transport and to neuronal activity. Here, we focus on physiological processes of energy dynamics in astrocytes as well as on the transfer of energetic substrates to neurons.
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Affiliation(s)
- Joachim W Deitmer
- Department of Biology, University of Kaiserslautern, Kaiserslautern, Germany
| | - Shefeeq M Theparambil
- Centre for Cardiovascular and Metabolic Neuroscience, Department of Neuroscience, Physiology and Pharmacology, University College London, London, United Kingdom
| | | | - Sina I Noor
- Centre for Organismal Studies, Heidelberg University, Heidelberg, Germany
| | - Holger M Becker
- Institute of Physiological Chemistry, University of Veterinary Medicine Hanover, Hanover, Germany
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15
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Provensi G, Carta F, Nocentini A, Supuran CT, Casamenti F, Passani MB, Fossati S. A New Kid on the Block? Carbonic Anhydrases as Possible New Targets in Alzheimer's Disease. Int J Mol Sci 2019; 20:E4724. [PMID: 31554165 PMCID: PMC6801497 DOI: 10.3390/ijms20194724] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Revised: 09/20/2019] [Accepted: 09/20/2019] [Indexed: 12/28/2022] Open
Abstract
The increase in the incidence of neurodegenerative diseases, in particular Alzheimer's Disease (AD), is a consequence of the world's population aging but unfortunately, existing treatments are only effective at delaying some of the symptoms and for a limited time. Despite huge efforts by both academic researchers and pharmaceutical companies, no disease-modifying drugs have been brought to the market in the last decades. Recently, several studies shed light on Carbonic Anhydrases (CAs, EC 4.2.1.1) as possible new targets for AD treatment. In the present review we summarized preclinical and clinical findings regarding the role of CAs and their inhibitors/activators on cognition, aging and neurodegeneration and we discuss future challenges and opportunities in the field.
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Affiliation(s)
- Gustavo Provensi
- Department of Neuroscience, Psychology, Drug Research and Child Health (NEUROFARBA), Section of Pharmacology of Toxicology, University of Florence, 50139 Florence, Italy.
| | - Fabrizio Carta
- Department of Neuroscience, Psychology, Drug Research and Child Health (NEUROFARBA), Section of Pharmaceutical and Nutraceutical Sciences, University of Florence, 50019 Florence, Italy.
| | - Alessio Nocentini
- Department of Neuroscience, Psychology, Drug Research and Child Health (NEUROFARBA), Section of Pharmaceutical and Nutraceutical Sciences, University of Florence, 50019 Florence, Italy.
| | - Claudiu T Supuran
- Department of Neuroscience, Psychology, Drug Research and Child Health (NEUROFARBA), Section of Pharmaceutical and Nutraceutical Sciences, University of Florence, 50019 Florence, Italy.
| | - Fiorella Casamenti
- Department of Neuroscience, Psychology, Drug Research and Child Health (NEUROFARBA), Section of Pharmacology of Toxicology, University of Florence, 50139 Florence, Italy.
| | - M Beatrice Passani
- Department of Health Sciences (DSS), Section of Clinical Pharmacology and Oncology, University of Florence, 50139 Florence, Italy.
| | - Silvia Fossati
- Alzheimer's Center at Temple (ACT), Department of Pharmacology, Lewis Katz School of Medicine, Temple University, Philadelphia, PA 19140, USA.
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16
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Jiang S, Wang X, Wei J, Zhang G, Zhang J, Xie P, Xu L, Wang L, Zhao L, Li L, Wilcox CS, Chen J, Lai EY, Liu R. NaHCO 3 Dilates Mouse Afferent Arteriole Via Na +/HCO 3- Cotransporters NBCs. Hypertension 2019; 74:1104-1112. [PMID: 31522618 DOI: 10.1161/hypertensionaha.119.13235] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Sodium bicarbonate has long been used to treat chronic kidney disease. It has been demonstrated to slow the decline in glomerular filtration rate in chronic kidney disease patient; however, the mechanisms are not completely understood. We hypothesized that NaHCO3 dilates afferent arterioles (Af-Art) by stimulating nitric oxide (NO) release mediated by the Na+/HCO3- cotransporter (NBC) contributing to the elevation in glomerular filtration rate. Isolated microperfused mouse renal Af-Art, preconstricted with norepinephrine (1 µmol/L), dilated 45±2% (n=6, P<0.05) in response to NaHCO3 (44 mmol/L). Whereas, NaCl solution containing the same Na+ concentration was not effective. The mRNA for NBCn1 and NBCe1 were detected in microdissected Af-Art using reverse transcription-polymerase chain reaction and quantitative polymerase chain reaction. The Af-Art intracellular pH measured with 2',7'-bis-(2-carboxyethyl)-5-(and-6) carboxyfluorescein, acetoxymethyl ester increased significantly by 0.29±0.02 (n=6; P<0.05) in the presence of NaHCO3, which was blunted by N-cyanosulphonamide compound (S0859) that is an inhibitor of the NBC family. After clamping the intracellular pH with 10 μM nigericin, changing the bath solution pH from 7.4 to 7.8 still dilates the Af-Art by 53±4% (n=7; P<0.005) and increases NO generation by 22±3% (n=7; P<0.005). Both pH-induced NO generation and vasodilation were blocked by L-NG-Nitroarginine Methyl Ester. NaHCO3 increased NO generation in Af-Art by 19±4% (n=5; P<0.005) and elevated glomerular filtration rate in conscious mice by 36% (233 versus 318 ul/min; n=9-10; P<0.0001). S0859 and L-NG-nitroarginine methyl ester blocked NaHCO3-induced increases in NO generation and vasodilation. We conclude that NBCn1 and NBCe1 are expressed in Af-Art and that NaHCO3 dilates Af-Art via NBCs mediated by NO that increases the glomerular filtration rate.
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Affiliation(s)
- Shan Jiang
- From Kidney Disease Center, the First Affiliated Hospital, and Department of Physiology, School of Basic Medical Sciences, Zhejiang University School of Medicine, Hangzhou, China (S.J., G.Z., P.X., L.Z., L.L., J.C., E.Y.L.).,Department of Molecular Pharmacology and Physiology, University of South Florida College of Medicine, Tampa (S.J., X.W., J.W., G.Z., J.Z., L.W., R.L.)
| | - Ximing Wang
- Department of Molecular Pharmacology and Physiology, University of South Florida College of Medicine, Tampa (S.J., X.W., J.W., G.Z., J.Z., L.W., R.L.).,Shandong Provincial Hospital, Affiliated Hospital of Shandong University, Jinan, China (X.W.)
| | - Jin Wei
- Department of Molecular Pharmacology and Physiology, University of South Florida College of Medicine, Tampa (S.J., X.W., J.W., G.Z., J.Z., L.W., R.L.)
| | - Gensheng Zhang
- From Kidney Disease Center, the First Affiliated Hospital, and Department of Physiology, School of Basic Medical Sciences, Zhejiang University School of Medicine, Hangzhou, China (S.J., G.Z., P.X., L.Z., L.L., J.C., E.Y.L.).,Department of Molecular Pharmacology and Physiology, University of South Florida College of Medicine, Tampa (S.J., X.W., J.W., G.Z., J.Z., L.W., R.L.)
| | - Jie Zhang
- Department of Molecular Pharmacology and Physiology, University of South Florida College of Medicine, Tampa (S.J., X.W., J.W., G.Z., J.Z., L.W., R.L.)
| | - Peng Xie
- From Kidney Disease Center, the First Affiliated Hospital, and Department of Physiology, School of Basic Medical Sciences, Zhejiang University School of Medicine, Hangzhou, China (S.J., G.Z., P.X., L.Z., L.L., J.C., E.Y.L.)
| | - Lan Xu
- College of Public Health, University of South Florida, Tampa (L.X.)
| | - Lei Wang
- Department of Molecular Pharmacology and Physiology, University of South Florida College of Medicine, Tampa (S.J., X.W., J.W., G.Z., J.Z., L.W., R.L.)
| | - Liang Zhao
- From Kidney Disease Center, the First Affiliated Hospital, and Department of Physiology, School of Basic Medical Sciences, Zhejiang University School of Medicine, Hangzhou, China (S.J., G.Z., P.X., L.Z., L.L., J.C., E.Y.L.).,Department of Physiology, School of Basic Medical Sciences, Guangzhou Medical University, China (L.Z., E.Y.L.).,Institute of Vegetative Physiology, Charité-Universitätsmedizin Berlin, Humboldt-Universität zu Berlin, Germany (L.Z., E.Y.L.)
| | - Lingli Li
- From Kidney Disease Center, the First Affiliated Hospital, and Department of Physiology, School of Basic Medical Sciences, Zhejiang University School of Medicine, Hangzhou, China (S.J., G.Z., P.X., L.Z., L.L., J.C., E.Y.L.).,Division of Nephrology and Hypertension, and Hypertension Center, Georgetown University, Washington, DC (L.L., C.S.W.)
| | - Christopher S Wilcox
- Division of Nephrology and Hypertension, and Hypertension Center, Georgetown University, Washington, DC (L.L., C.S.W.)
| | - Jianghua Chen
- From Kidney Disease Center, the First Affiliated Hospital, and Department of Physiology, School of Basic Medical Sciences, Zhejiang University School of Medicine, Hangzhou, China (S.J., G.Z., P.X., L.Z., L.L., J.C., E.Y.L.)
| | - En Yin Lai
- From Kidney Disease Center, the First Affiliated Hospital, and Department of Physiology, School of Basic Medical Sciences, Zhejiang University School of Medicine, Hangzhou, China (S.J., G.Z., P.X., L.Z., L.L., J.C., E.Y.L.).,Department of Physiology, School of Basic Medical Sciences, Guangzhou Medical University, China (L.Z., E.Y.L.).,Institute of Vegetative Physiology, Charité-Universitätsmedizin Berlin, Humboldt-Universität zu Berlin, Germany (L.Z., E.Y.L.)
| | - Ruisheng Liu
- Department of Molecular Pharmacology and Physiology, University of South Florida College of Medicine, Tampa (S.J., X.W., J.W., G.Z., J.Z., L.W., R.L.)
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17
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Bonnet U, Bingmann D, Speckmann EJ, Wiemann M. Levetiracetam mediates subtle pH-shifts in adult human neocortical pyramidal cells via an inhibition of the bicarbonate-driven neuronal pH-regulation - Implications for excitability and plasticity modulation. Brain Res 2019; 1710:146-156. [PMID: 30590026 DOI: 10.1016/j.brainres.2018.12.039] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Revised: 11/24/2018] [Accepted: 12/23/2018] [Indexed: 01/20/2023]
Abstract
The intracellular pH (pHi) of mammalian central neurons is tightly regulated and small pHi-fluctuations can fine-tune inter-/intracellular signaling, excitability, and synaptic plasticity. The research-gap about the pHi-regulation of human brain neurons is addressed here by testing possible influences of the anticonvulsant levetiracetam (LEV). BCECF-AM-loaded neocortical pyramidal cells were fluorometrically investigated in slice-preparations of tissue resected from the middle temporal gyrus of five adults with intractable temporal-lobe epilepsy. Recovery-slope from intracellular acidification following an ammonium prepulse (APP) was used to measure the pHi-regulation. Among twenty pyramidal cells exposed to 50 μM LEV, the resting pHi (7.09 ± 0.14) was lowered in eight (40%) neurons, on average by 0.02 ± 0.011 pH-units. In three (15%) and nine (45%) neurons, a minimal alkaline shift (0.017 ± 0.004 pH-units) and no pHi-shift occurred, respectively. The LEV-induced pHi-shifts were positively correlated with the resting pHi (r = 0.6, p = 0.006, n = 20). In five neurons, which all had responded on LEV with an acidification before, the recovery from APP-acidification was significantly delayed during LEV (p < 0.001). This inhibitory LEV-effect on pHi-regulation i) was similar to that of 200 μM 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid (n = 2) and ii) did not occur under nominal bicarbonate-free conditions (n = 2). Thus, LEV lowered the pHi of human neocortical pyramidal cells most likely by a weakening of the transmembrane HCO3(-)-mediated acid-extrusion. This might contribute to LEV's anticonvulsive potency. Neurons with more acidic resting pHi-values showed a minimal alkalization upon LEV providing a mechanism for paradoxical proconvulsive LEV-effects rarely observed in epilepsy patients. The significance of these subtle pHi-shifts for cortical excitability and plasticity is discussed.
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Affiliation(s)
- Udo Bonnet
- Department of Psychiatry, Psychotherapy, and Psychosomatic Medicine, Evangelisches Krankenhaus Castrop-Rauxel, Academic Teaching Hospital of the University Duisburg-Essen, Castrop-Rauxel, Germany; Department of Psychiatry and Psychotherapy, Faculty of Medicine, LVR-Hospital Essen, University of Duisburg-Essen, Essen, Germany.
| | - Dieter Bingmann
- Institute of Physiology, University of Duisburg-Essen, Essen, Germany
| | | | - Martin Wiemann
- Institute of Physiology, University of Duisburg-Essen, Essen, Germany; IBE R&D gGmbH, Institute for Lung Health, D-48149 Münster, Germany
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18
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Forero-Quintero LS, Ames S, Schneider HP, Thyssen A, Boone CD, Andring JT, McKenna R, Casey JR, Deitmer JW, Becker HM. Membrane-anchored carbonic anhydrase IV interacts with monocarboxylate transporters via their chaperones CD147 and GP70. J Biol Chem 2018; 294:593-607. [PMID: 30446621 DOI: 10.1074/jbc.ra118.005536] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2018] [Revised: 11/12/2018] [Indexed: 12/20/2022] Open
Abstract
Monocarboxylate transporters (MCTs) mediate the proton-coupled exchange of high-energy metabolites, including lactate and pyruvate, between cells and tissues. The transport activity of MCT1, MCT2, and MCT4 can be facilitated by the extracellular carbonic anhydrase IV (CAIV) via a noncatalytic mechanism. Combining physiological measurements in HEK-293 cells and Xenopus oocytes with pulldown experiments, we analyzed the direct interaction between CAIV and the two MCT chaperones basigin (CD147) and embigin (GP70). Our results show that facilitation of MCT transport activity requires direct binding of CAIV to the transporters chaperones. We found that this binding is mediated by the highly conserved His-88 residue in CAIV, which is also the central residue of the enzyme's intramolecular proton shuttle, and a charged amino acid residue in the Ig1 domain of the chaperone. Although the position of the CAIV-binding site in the chaperone was conserved, the amino acid residue itself varied among different species. In human CD147, binding of CAIV was mediated by the negatively charged Glu-73 and in rat CD147 by the positively charged Lys-73. In rat GP70, we identified the positively charged Arg-130 as the binding site. Further analysis of the CAIV-binding site revealed that the His-88 in CAIV can either act as H donor or H acceptor for the hydrogen bond, depending on the charge of the binding residue in the chaperone. Our results suggest that the CAIV-mediated increase in MCT transport activity requires direct binding between CAIV-His-88 and a charged amino acid in the extracellular domain of the transporter's chaperone.
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Affiliation(s)
- Linda S Forero-Quintero
- From the Division of General Zoology, Department of Biology, University of Kaiserlautern, D-67653 Kaiserslautern, Germany
| | - Samantha Ames
- From the Division of General Zoology, Department of Biology, University of Kaiserlautern, D-67653 Kaiserslautern, Germany
| | - Hans-Peter Schneider
- From the Division of General Zoology, Department of Biology, University of Kaiserlautern, D-67653 Kaiserslautern, Germany
| | - Anne Thyssen
- From the Division of General Zoology, Department of Biology, University of Kaiserlautern, D-67653 Kaiserslautern, Germany
| | - Christopher D Boone
- the Department of Biochemistry and Molecular Biology, University of Florida, Gainesville, Florida 32610
| | - Jacob T Andring
- the Department of Biochemistry and Molecular Biology, University of Florida, Gainesville, Florida 32610
| | - Robert McKenna
- the Department of Biochemistry and Molecular Biology, University of Florida, Gainesville, Florida 32610
| | - Joseph R Casey
- the Department of Biochemistry, Membrane Protein Disease Research Group, University of Alberta, Edmonton, Alberta T6G 2E1, Canada, and
| | - Joachim W Deitmer
- From the Division of General Zoology, Department of Biology, University of Kaiserlautern, D-67653 Kaiserslautern, Germany
| | - Holger M Becker
- From the Division of General Zoology, Department of Biology, University of Kaiserlautern, D-67653 Kaiserslautern, Germany, .,the Institute of Physiological Chemistry, University of Veterinary Medicine Hannover, D-30559 Hannover, Germany
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Chamessian A, Young M, Qadri Y, Berta T, Ji RR, Van de Ven T. Transcriptional Profiling of Somatostatin Interneurons in the Spinal Dorsal Horn. Sci Rep 2018; 8:6809. [PMID: 29717160 PMCID: PMC5931607 DOI: 10.1038/s41598-018-25110-7] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2017] [Accepted: 04/13/2018] [Indexed: 01/08/2023] Open
Abstract
The spinal dorsal horn (SDH) is comprised of distinct neuronal populations that process different somatosensory modalities. Somatostatin (SST)-expressing interneurons in the SDH have been implicated specifically in mediating mechanical pain. Identifying the transcriptomic profile of SST neurons could elucidate the unique genetic features of this population and enable selective analgesic targeting. To that end, we combined the Isolation of Nuclei Tagged in Specific Cell Types (INTACT) method and Fluorescence Activated Nuclei Sorting (FANS) to capture tagged SST nuclei in the SDH of adult male mice. Using RNA-sequencing (RNA-seq), we uncovered more than 13,000 genes. Differential gene expression analysis revealed more than 900 genes with at least 2-fold enrichment. In addition to many known dorsal horn genes, we identified and validated several novel transcripts from pharmacologically tractable functional classes: Carbonic Anhydrase 12 (Car12), Phosphodiesterase 11 A (Pde11a), and Protease-Activated Receptor 3 (F2rl2). In situ hybridization of these novel genes showed differential expression patterns in the SDH, demonstrating the presence of transcriptionally distinct subpopulations within the SST population. Overall, our findings provide new insights into the gene repertoire of SST dorsal horn neurons and reveal several novel targets for pharmacological modulation of this pain-mediating population and treatment of pathological pain.
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Affiliation(s)
- Alexander Chamessian
- Department of Anesthesiology, Duke University Medical Center, Durham, North Carolina, 27710, USA. .,Medical Scientist Training Program, Duke University School of Medicine, Durham, North Carolina, 27710, USA. .,Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina, 27710, USA.
| | - Michael Young
- Department of Neurobiology, Duke University Medical Center, Durham, North Carolina, 27710, USA
| | - Yawar Qadri
- Department of Anesthesiology, Duke University Medical Center, Durham, North Carolina, 27710, USA
| | - Temugin Berta
- Pain Research Center, Department of Anesthesiology, University of Cincinnati Medical Center, Cincinnati, Ohio, 45267, USA
| | - Ru-Rong Ji
- Department of Anesthesiology, Duke University Medical Center, Durham, North Carolina, 27710, USA.,Department of Neurobiology, Duke University Medical Center, Durham, North Carolina, 27710, USA
| | - Thomas Van de Ven
- Department of Anesthesiology, Duke University Medical Center, Durham, North Carolina, 27710, USA
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Intrinsic thermodynamics of high affinity inhibitor binding to recombinant human carbonic anhydrase IV. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2017; 47:271-290. [PMID: 28975383 DOI: 10.1007/s00249-017-1256-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2017] [Revised: 09/07/2017] [Accepted: 09/15/2017] [Indexed: 10/18/2022]
Abstract
Membrane-associated carbonic anhydrase (CA) isoform IV participates in carbon metabolism and pH homeostasis and is implicated in the development of eye diseases such as retinitis pigmentosa and glaucoma. A series of substituted benzenesulfonamides were designed and their binding affinity to CA IV was determined by fluorescent thermal shift assay and isothermal titration calorimetry (ITC). Compound [(4-chloro-2-phenylsulfanyl-5-sulfamoyl-benzoyl)amino]propyl acetate (19) bound CA IV with the K d of 1.0 nM and exhibited significant selectivity over the remaining 11 human CA isoforms. The compound could be developed as a drug targeting CA IV. Various forms of recombinant CA IV were produced in Escherichia coli and mammalian cell cultures. Comparison of their temperature stability in various buffers and salt solutions demonstrated that CA IV is most stable at slightly alkaline conditions and at elevated sodium sulfate concentrations. High-resolution X-ray crystallographic structures of ortho-Cl and meta-thiazole-substituted benzene sulfonamide in complex with CA IV revealed the position of and interactions between the ligand and the protein. Sulfonamide inhibitor binding to CA IV is linked to several reactions-the deprotonation of the sulfonamide amino group, the protonation of CA-Zn(II)-bound hydroxide at the active site of CA IV, and the compensating reactions of the buffer. The dissection of binding-linked reactions yielded the intrinsic thermodynamic parameters, characterizing the interaction between CA IV and the sulfonamides in the binding-able protonation forms, including Gibbs energy, enthalpy, and entropy, that could be used for the characterization of binding to any CA in the process of drug design.
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Vairamani K, Wang HS, Medvedovic M, Lorenz JN, Shull GE. RNA SEQ Analysis Indicates that the AE3 Cl -/HCO 3- Exchanger Contributes to Active Transport-Mediated CO 2 Disposal in Heart. Sci Rep 2017; 7:7264. [PMID: 28779178 PMCID: PMC5544674 DOI: 10.1038/s41598-017-07585-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Accepted: 06/29/2017] [Indexed: 02/06/2023] Open
Abstract
Loss of the AE3 Cl−/HCO3− exchanger (Slc4a3) in mice causes an impaired cardiac force-frequency response and heart failure under some conditions but the mechanisms are not known. To better understand the functions of AE3, we performed RNA Seq analysis of AE3-null and wild-type mouse hearts and evaluated the data with respect to three hypotheses (CO2 disposal, facilitation of Na+-loading, and recovery from an alkaline load) that have been proposed for its physiological functions. Gene Ontology and PubMatrix analyses of differentially expressed genes revealed a hypoxia response and changes in vasodilation and angiogenesis genes that strongly support the CO2 disposal hypothesis. Differential expression of energy metabolism genes, which indicated increased glucose utilization and decreased fatty acid utilization, were consistent with adaptive responses to perturbations of O2/CO2 balance in AE3-null myocytes. Given that the myocardium is an obligate aerobic tissue and consumes large amounts of O2, the data suggest that loss of AE3, which has the potential to extrude CO2 in the form of HCO3−, impairs O2/CO2 balance in cardiac myocytes. These results support a model in which the AE3 Cl−/HCO3− exchanger, coupled with parallel Cl− and H+-extrusion mechanisms and extracellular carbonic anhydrase, is responsible for active transport-mediated disposal of CO2.
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Affiliation(s)
- Kanimozhi Vairamani
- Department of Molecular Genetics, Biochemistry and Microbiology, University of Cincinnati College of Medicine, Cincinnati, Ohio, 45267, USA
| | - Hong-Sheng Wang
- Department of Pharmacology and Cell Biophysics, University of Cincinnati College of Medicine, Cincinnati, Ohio, 45267, USA
| | - Mario Medvedovic
- Department of Environmental Health, University of Cincinnati College of Medicine, Cincinnati, Ohio, 45267, USA
| | - John N Lorenz
- Department of Cellular and Molecular Physiology, University of Cincinnati College of Medicine, Cincinnati, Ohio, 45267, USA
| | - Gary E Shull
- Department of Molecular Genetics, Biochemistry and Microbiology, University of Cincinnati College of Medicine, Cincinnati, Ohio, 45267, USA.
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22
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Salameh AI, Hübner CA, Boron WF. Role of Cl - -HCO 3- exchanger AE3 in intracellular pH homeostasis in cultured murine hippocampal neurons, and in crosstalk to adjacent astrocytes. J Physiol 2016; 595:93-124. [PMID: 27353306 DOI: 10.1113/jp272470] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2016] [Accepted: 06/20/2016] [Indexed: 12/11/2022] Open
Abstract
KEY POINTS A polymorphism of human AE3 is associated with idiopathic generalized epilepsy. Knockout of AE3 in mice lowers the threshold for triggering epileptic seizures. The explanations for these effects are elusive. Comparisons of cells from wild-type vs. AE3-/- mice show that AE3 (present in hippocampal neurons, not astrocytes; mediates HCO3- efflux) enhances intracellular pH (pHi ) recovery (decrease) from alkali loads in neurons and, surprisingly, adjacent astrocytes. During metabolic acidosis (MAc), AE3 speeds initial acidification, but limits the extent of pHi decrease in neurons and astrocytes. AE3 speeds re-alkalization after removal of MAc in neurons and astrocytes, and speeds neuronal pHi recovery from an ammonium prepulse-induced acid load. We propose that neuronal AE3 indirectly increases acid extrusion in (a) neurons via Cl- loading, and (b) astrocytes by somehow enhancing NBCe1 (major acid extruder). The latter would enhance depolarization-induced alkalinization of astrocytes, and extracellular acidification, and thereby reduce susceptibility to epileptic seizures. ABSTRACT The anion exchanger AE3, expressed in hippocampal (HC) neurons but not astrocytes, contributes to intracellular pH (pHi ) regulation by facilitating the exchange of extracellular Cl- for intracellular HCO3- . The human AE3 polymorphism A867D is associated with idiopathic generalized epilepsy. Moreover, AE3 knockout (AE3-/- ) mice are more susceptible to epileptic seizure. The mechanism of these effects has been unclear because the starting pHi in AE3-/- and wild-type neurons is indistinguishable. The purpose of the present study was to use AE3-/- mice to investigate the role of AE3 in pHi homeostasis in HC neurons, co-cultured with astrocytes. We find that the presence of AE3 increases the acidification rate constant during pHi recovery from intracellular alkaline loads imposed by reducing [CO2 ]. The presence of AE3 also speeds intracellular acidification during the early phase of metabolic acidosis (MAc), not just in neurons but, surprisingly, in adjacent astrocytes. Additionally, AE3 contributes to braking the decrease in pHi later during MAc in both neurons and astrocytes. Paradoxically, AE3 enhances intracellular re-alkalization after MAc removal in neurons and astrocytes, and pHi recovery from an ammonium prepulse-induced acid load in neurons. The effects of AE3 knockout on astrocytic pHi homeostasis in MAc-related assays require the presence of neurons, and are consistent with the hypothesis that the AE3 knockout reduces functional expression of astrocytic NBCe1. These findings suggest a new type of neuron-astrocyte communication, based on the expression of AE3 in neurons, which could explain how AE3 reduces seizure susceptibility.
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Affiliation(s)
- Ahlam I Salameh
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
| | | | - Walter F Boron
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
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Amiloride-Insensitive Salt Taste Is Mediated by Two Populations of Type III Taste Cells with Distinct Transduction Mechanisms. J Neurosci 2016; 36:1942-53. [PMID: 26865617 DOI: 10.1523/jneurosci.2947-15.2016] [Citation(s) in RCA: 87] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
UNLABELLED Responses in the amiloride-insensitive (AI) pathway, one of the two pathways mediating salty taste in mammals, are modulated by the size of the anion of a salt. This "anion effect" has been hypothesized to result from inhibitory transepithelial potentials (TPs) generated across the lingual epithelium as cations permeate through tight junctions and leave their larger and less permeable anions behind (Ye et al., 1991). We tested directly the necessity of TPs for the anion effect by measuring responses to NaCl and Na-gluconate (small and large anion sodium salts, respectively) in isolated taste cells from mouse circumvallate papillae. Using calcium imaging, we identified AI salt-responsive type III taste cells and demonstrated that they compose a subpopulation of acid-responsive taste cells. Even in the absence of TPs, many (66%) AI salt-responsive type III taste cells still exhibited the anion effect, demonstrating that some component of the transduction machinery for salty taste in type III cells is sensitive to anion size. We hypothesized that osmotic responses could explain why a minority of type III cells (34%) had AI salt responses but lacked anion sensitivity. All AI type III cells had osmotic responses to cellobiose, which were significantly modulated by extracellular sodium concentration, suggesting the presence of a sodium-conducting osmotically sensitive ion channel. However, these responses were significantly larger in AI type III cells that did not exhibit the anion effect. These findings indicate that multiple mechanisms could underlie AI salt responses in type III taste cells, one of which may contribute to the anion effect. SIGNIFICANCE STATEMENT Understanding the mechanisms underlying salty taste will help inform strategies to combat the health problems associated with NaCl overconsumption by humans. Of the two pathways underlying salty taste in mammals, the amiloride-insensitive (AI) pathway is the least understood. Using calcium imaging of isolated mouse taste cells, we identify two separate populations of AI salt-responsive type III taste cells distinguished by their sensitivity to anion size and show that these cells compose subpopulations of acid-responsive taste cells. We also find evidence that a sodium-conducting osmotically sensitive mechanism contributes to salt responses in type III taste cells. Our data not only provide new insights into the transduction mechanisms of AI salt taste but also have important implications for general theories of taste encoding.
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Eyre HA, Eskin A, Nelson SF, St. Cyr NM, Siddarth P, Baune BT, Lavretsky H. Genomic predictors of remission to antidepressant treatment in geriatric depression using genome-wide expression analyses: a pilot study. Int J Geriatr Psychiatry 2016; 31:510-7. [PMID: 26471432 PMCID: PMC5567872 DOI: 10.1002/gps.4356] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/04/2015] [Accepted: 08/21/2015] [Indexed: 02/03/2023]
Abstract
OBJECTIVE This first pilot study of genome-wide expression as predictor of antidepressant response in late-life depression examined genome-wide transcriptional profiles in a randomized placebo-controlled trial of combined methylphenidate and citalopram. METHODS Genome-wide transcriptional profiles were examined in peripheral blood leukocytes sampled at baseline and 16 weeks from 35 older adults with major depression, who were randomized to methylphenidate + citalopram, citalopram + placebo, or methylphenidate + placebo. Methylphenidate doses ranged between 10 and 40 mg/day, and citalopram doses ranged between 20 and 60 mg/day. Remission was defined as Hamilton Depression Rating Scale score of 6 or below. Early remission was achieved in the first 4 weeks of treatment. We hypothesized that differential gene expression at baseline can predict antidepressant response. RESULTS We analyzed gene expression in 24 remitters and 11 non-remitters. At baseline, we found three genes showing higher expression in all remitters versus non-remitters that satisfied the established level of significance: a fold change of 2 and p-value of 0.05 that included HLA-DRB5, SELENBP1, and LOC388588. Two gene transcripts showed higher expression in early remitters at baseline compared with non-remitters. The first gene was CA1 carbonic anhydrase gene, on chromosome 8 involved in respiratory function (fold change 2.54; p = 0.03). The second gene was the SNCA-α-synuclein gene, implicated, which binds to dopamine transporter (fold change 2.1; p = 0.03). CONCLUSIONS Remission to antidepressants in geriatric depression may be associated with a particular gene expression profile in monoaminergic and metabolic pathways and needs to be replicated in a larger sample.
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Affiliation(s)
- Harris A. Eyre
- Discipline of Psychiatry, University of Adelaide, Adelaide, South Australia, Australia,UCLA Semel Institute for Neuroscience and Human Behavior, UCLA, Los Angeles, CA, USA
| | - Ascia Eskin
- Department of Human Genetics, UCLA, Los Angeles, CA, USA
| | | | - Natalie M. St. Cyr
- UCLA Semel Institute for Neuroscience and Human Behavior, UCLA, Los Angeles, CA, USA
| | - Prabha Siddarth
- UCLA Semel Institute for Neuroscience and Human Behavior, UCLA, Los Angeles, CA, USA
| | - Bernhard T. Baune
- Discipline of Psychiatry, University of Adelaide, Adelaide, South Australia, Australia
| | - Helen Lavretsky
- UCLA Semel Institute for Neuroscience and Human Behavior, UCLA, Los Angeles, CA, USA
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Rodrigues AM, Santos LEC, Covolan L, Hamani C, de Almeida ACG. pH during non-synaptic epileptiform activity—computational simulations. Phys Biol 2015; 12:056007. [DOI: 10.1088/1478-3975/12/5/056007] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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26
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Theparambil SM, Naoshin Z, Thyssen A, Deitmer JW. Reversed electrogenic sodium bicarbonate cotransporter 1 is the major acid loader during recovery from cytosolic alkalosis in mouse cortical astrocytes. J Physiol 2015; 593:3533-47. [PMID: 25990710 DOI: 10.1113/jp270086] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Accepted: 05/17/2015] [Indexed: 12/29/2022] Open
Abstract
KEY POINTS The regulation of H(+) i from cytosolic alkalosis has generally been attributed to the activity of Cl(-) -coupled acid loaders/base extruders in most cell types, including brain cells. The present study demonstrates that outwardly-directed sodium bicarbonate cotransport via electrogenic sodium bicarbonate cotransporter 1 (NBCe1) mediates the major fraction of H(+) i regulation from cytosolic alkalosis in mouse cortical astrocytes. Cl(-) -coupled acid-loading transporters play only a minor role in the regulation of H(+) i from alkalosis in mouse cortical astrocytes. NBCe1-mediated H(+) i regulation from alkalosis was dominant, with the support of intracellular carbonic anhydrase II, even when the intra- and extracellular [HCO3 (-) ] was very low (<1mM), as in nominally CO2 /HCO3 (-) free condition. A reversed NBCe1 in astrocytes may also be significant for stabilizing extracellular pH in brain tissue. ABSTRACT Recovery of intracellular pH from cytosolic alkalosis has been attributed primarily to Cl(-) coupled acid loaders/base extruders such as Cl(-) /HCO3 (-) or Cl(-) /OH(-) exchangers. We have studied this process in cortical astrocytes from wild-type and transgenic mouse models with gene deletion for the electrogenic sodium bicarbonate cotransporter 1 (NBCe1) and for carbonic anhydrase (CA) isoform II. An acute cytosolic alkalosis was induced by the removal of either CO2 /HCO3 (-) or butyric acid, and the subsequent acid loading was analysed by monitoring changes in cytosolic H(+) or Na(+) using ion-sensitive fluorescent dyes. We have identified that NBCe1 reverses during alkalosis and contributes more than 70% to the rate of recovery from alkalosis by extruding Na(+) and HCO3 (-) . After CA inhibition or in CAII-knockout (KO) cells, the rate of recovery was reduced by 40%, and even by 70% in the nominal absence of CO2 /HCO3 (-) . Increasing the extracellular K(+) concentration modulated the rate of acid loading in wild-type cells, but not in NBCe1-KO cells. Removing chloride had only a minor effect on the recovery from alkalosis. Reversal of NBCe1 by reducing pH/[HCO3 (-) ] was demonstrated in astrocytes and in Xenopus oocytes, in which human NBCe1 was heterologously expressed. The results obtained suggest that reversed NBCe1, supported by CAII activity, plays a major role in acid-loading cortical astrocytes to support recovery from cytosolic alkalosis.
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Affiliation(s)
- Shefeeq M Theparambil
- Department of General Zoology, Faculty of Biology, University of Kaiserslautern, Kaiserslautern, Germany
| | - Zinnia Naoshin
- Department of General Zoology, Faculty of Biology, University of Kaiserslautern, Kaiserslautern, Germany
| | - Anne Thyssen
- Department of General Zoology, Faculty of Biology, University of Kaiserslautern, Kaiserslautern, Germany
| | - Joachim W Deitmer
- Department of General Zoology, Faculty of Biology, University of Kaiserslautern, Kaiserslautern, Germany
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Rungta R, Choi H, Tyson J, Malik A, Dissing-Olesen L, Lin P, Cain S, Cullis P, Snutch T, MacVicar B. The Cellular Mechanisms of Neuronal Swelling Underlying Cytotoxic Edema. Cell 2015; 161:610-621. [DOI: 10.1016/j.cell.2015.03.029] [Citation(s) in RCA: 150] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2014] [Revised: 02/03/2015] [Accepted: 03/12/2015] [Indexed: 01/08/2023]
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28
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Ruffin VA, Salameh AI, Boron WF, Parker MD. Intracellular pH regulation by acid-base transporters in mammalian neurons. Front Physiol 2014; 5:43. [PMID: 24592239 PMCID: PMC3923155 DOI: 10.3389/fphys.2014.00043] [Citation(s) in RCA: 112] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2013] [Accepted: 01/23/2014] [Indexed: 12/22/2022] Open
Abstract
Intracellular pH (pHi) regulation in the brain is important in both physiological and physiopathological conditions because changes in pHi generally result in altered neuronal excitability. In this review, we will cover 4 major areas: (1) The effect of pHi on cellular processes in the brain, including channel activity and neuronal excitability. (2) pHi homeostasis and how it is determined by the balance between rates of acid loading (JL) and extrusion (JE). The balance between JE and JL determine steady-state pHi, as well as the ability of the cell to defend pHi in the face of extracellular acid-base disturbances (e.g., metabolic acidosis). (3) The properties and importance of members of the SLC4 and SLC9 families of acid-base transporters expressed in the brain that contribute to JL (namely the Cl-HCO3 exchanger AE3) and JE (the Na-H exchangers NHE1, NHE3, and NHE5 as well as the Na+- coupled HCO3− transporters NBCe1, NBCn1, NDCBE, and NBCn2). (4) The effect of acid-base disturbances on neuronal function and the roles of acid-base transporters in defending neuronal pHi under physiopathologic conditions.
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Affiliation(s)
- Vernon A Ruffin
- Department of Physiology and Biophysics, Case Western Reserve University OH, USA
| | - Ahlam I Salameh
- Department of Physiology and Biophysics, Case Western Reserve University OH, USA
| | - Walter F Boron
- Department of Physiology and Biophysics, Case Western Reserve University OH, USA
| | - Mark D Parker
- Department of Physiology and Biophysics, Case Western Reserve University OH, USA
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Abstract
Carbonic anhydrases (CAs) have not only been identified as ubiquitous enzymes catalyzing the fast reversible hydration of carbon dioxide to generate or consume protons and bicarbonate, but also as intra- and extracellular proteins, which facilitate transport function of many acid/base transporting membrane proteins, coined 'transport metabolon'. Functional interaction between CAs and acid/base transporters, such as chloride/bicarbonate exchanger (AE), sodium-bicarbonate cotransporter (NBC) and sodium/hydrogen exchanger (NHE) has been shown to require both catalytic CA activity as well as direct binding of the enzyme to specific sites on the transporter. In contrast, functional interaction between different CA isoforms and lactate-proton-cotransporting monocarboxylate transporters (MCT) has been found to be isoform-specific and independent of CA catalytic activity, but seems to require an intramolecular proton shuttle within the enzyme. In this chapter, we review the various types of interactions between acid/base-coupled membrane carriers and different CA isoforms, as studied in vitro, in intact Xenopus oocytes, and in various mammalian cell types. Furthermore, we discuss recent findings that indicate the significance of these 'transport metabolons' for normal cell functions.
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Abstract
H(+) ions are remarkably efficient modulators of neuronal excitability. This renders brain functions highly sensitive to small changes in pH which are generated "extrinsically" via mechanisms that regulate the acid-base status of the whole organism; and "intrinsically", by activity-induced transmembrane fluxes and de novo generation of acid-base equivalents. The effects of pH changes on neuronal excitability are mediated by diverse, largely synergistically-acting mechanisms operating at the level of voltage- and ligand-gated ion channels and gap junctions. In general, alkaline shifts induce an increase in excitability which is often intense enough to trigger epileptiform activity, while acidosis has the opposite effect. Brain pH changes show a wide variability in their spatiotemporal properties, ranging from long-lasting global shifts to fast and highly localized transients that take place in subcellular microdomains. Thirteen catalytically-active mammalian carbonic anhydrase isoforms have been identified, whereof 11 are expressed in the brain. Distinct CA isoforms which have their catalytic sites within brain cells and the interstitial fluid exert a remarkably strong influence on the dynamics of pH shifts and, consequently, on neuronal functions. In this review, we will discuss the various roles of H(+) as an intra- and extracellular signaling factor in the brain, focusing on the effects mediated by CAs. Special attention is paid on the developmental expression patterns and actions of the neuronal isoform, CA VII. Studies on the various functions of CAs will shed light on fundamental mechanisms underlying neuronal development, signaling and plasticity; on pathophysiological mechanisms associated with epilepsy and related diseases; and on the modes of action of CA inhibitors used as CNS-targeting drugs.
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Affiliation(s)
- Eva Ruusuvuori
- Department of Biosciences, University of Helsinki, Helsinki, Finland,
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Waheed A, Sly WS. Membrane associated carbonic anhydrase IV (CA IV): a personal and historical perspective. Subcell Biochem 2014; 75:157-79. [PMID: 24146379 DOI: 10.1007/978-94-007-7359-2_9] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Carbonic anhydrase IV is one of 12 active human isozymes and one of four expressed on the extracellular surfaces of certain endothelial and epithelial cells. It is unique in being attached to the plasma membrane by a glycosyl-phosphatiydyl-inositol (GPI) anchor rather than by a membrane-spanning domain. It is also uniquely resistant to high concentrations of sodium dodecyl sulfate (SDS), which allows purification from tissues by inhibitor affinity chromatography without contamination by other isozymes. This unique resistance to SDS and recovery following denaturation is explained by the two disulfide bonds. The 35-kDa human CA IV is a "high activity" isozyme in CO2 hydration activity, like CA II, and has higher activity than other isozymes in catalyzing the dehydration of HCO3 (-). Human CA IV is also unique in that it contains no oligosaccharide chains, where all other mammalian CA IVs are glycoproteins with one to several oligosaccharide side chains.Although CA IV has been shown to be active in mediating CO2 and HCO3 (-) transport in many important tissues like kidney and lung, and in isolated cells from brain and muscle, the gene for CA IV appears not to be essential. The CA IV knockout mouse produced by targeted mutagenesis, though slightly smaller and produced in lower than expected numbers, is viable and has no obvious mutant phenotype. Conversely, several dominant negative mutations in humans are associated with one form of reitinitis pigmentosa (RP-17), which we attribute to unfolded protein accumulation in the choreocapillaris, leading to apoptosis of cells in the overlying retina.
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Affiliation(s)
- Abdul Waheed
- Edward A. Doisy Department of Biochemistry and Molecular Biology, Saint Louis University, School of Medicine, St. Louis, MO, USA,
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Hübner CA, Holthoff K. Anion transport and GABA signaling. Front Cell Neurosci 2013; 7:177. [PMID: 24187533 PMCID: PMC3807543 DOI: 10.3389/fncel.2013.00177] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2013] [Accepted: 09/21/2013] [Indexed: 12/02/2022] Open
Abstract
Whereas activation of GABAA receptors by GABA usually results in a hyperpolarizing influx of chloride into the neuron, the reversed chloride driving force in the immature nervous system results in a depolarizing efflux of chloride. This GABAergic depolarization is deemed to be important for the maturation of the neuronal network. The concept of a developmental GABA switch has mainly been derived from in vitro experiments and reliable in vivo evidence is still missing. As GABAA receptors are permeable for both chloride and bicarbonate, the net effect of GABA also critically depends on the distribution of bicarbonate. Whereas chloride can either mediate depolarizing or hyperpolarizing currents, bicarbonate invariably mediates a depolarizing current under physiological conditions. Intracellular bicarbonate is quickly replenished by cytosolic carbonic anhydrases. Intracellular bicarbonate levels also depend on different bicarbonate transporters expressed by neurons. The expression of these proteins is not only developmentally regulated but also differs between cell types and even subcellular regions. In this review we will summarize current knowledge about the role of some of these transporters for brain development and brain function.
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Affiliation(s)
- Christian A Hübner
- Institute of Human Genetics, Jena University Hospital, Friedrich Schiller University Jena Jena, Germany
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33
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Sinning A, Hübner CA. Minireview: pH and synaptic transmission. FEBS Lett 2013; 587:1923-8. [PMID: 23669358 DOI: 10.1016/j.febslet.2013.04.045] [Citation(s) in RCA: 122] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2013] [Revised: 04/26/2013] [Accepted: 04/26/2013] [Indexed: 11/30/2022]
Abstract
As a general rule a rise in pH increases neuronal activity, whereas it is dampened by a fall of pH. Neuronal activity per se also challenges pH homeostasis by the increase of metabolic acid equivalents. Moreover, the negative membrane potential of neurons promotes the intracellular accumulation of protons. Synaptic key players such as glutamate receptors or voltage-gated calcium channels show strong pH dependence and effects of pH gradients on synaptic processes are well known. However, the processes and mechanisms that allow controlling the pH in synaptic structures and how these mechanisms contribute to normal synaptic function are only beginning to be resolved.
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Affiliation(s)
- Anne Sinning
- Institute of Human Genetics, University Hospital Jena, Friedrich Schiller University Jena, Kollegiengasse 10, D-07743 Jena, Germany
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Rossano AJ, Chouhan AK, Macleod GT. Genetically encoded pH-indicators reveal activity-dependent cytosolic acidification of Drosophila motor nerve termini in vivo. J Physiol 2013; 591:1691-706. [PMID: 23401611 PMCID: PMC3624846 DOI: 10.1113/jphysiol.2012.248377] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2012] [Accepted: 01/04/2013] [Indexed: 01/27/2023] Open
Abstract
All biochemical processes, including those underlying synaptic function and plasticity, are pH sensitive. Cytosolic pH (pH(cyto)) shifts are known to accompany nerve activity in situ, but technological limitations have prevented characterization of such shifts in vivo. Genetically encoded pH-indicators (GEpHIs) allow for tissue-specific in vivo measurement of pH. We expressed three different GEpHIs in the cytosol of Drosophila larval motor neurons and observed substantial presynaptic acidification in nerve termini during nerve stimulation in situ. SuperEcliptic pHluorin was the most useful GEpHI for studying pH(cyto) shifts in this model system. We determined the resting pH of the nerve terminal cytosol to be 7.30 ± 0.02, and observed a decrease of 0.16 ± 0.01 pH units when the axon was stimulated at 40 Hz for 4 s. Realkalinization occurred upon cessation of stimulation with a time course of 20.54 ± 1.05 s (τ). The chemical pH-indicator 2,7-bis-(2-carboxyethyl)-5-(and-6)-carboxyfluorescein corroborated these changes in pH(cyto). Bicarbonate-derived buffering did not contribute to buffering of acid loads from short (≤ 4 s) trains of action potentials but did buffer slow (~60 s) acid loads. The magnitude of cytosolic acid transients correlated with cytosolic Ca(2+) increase upon stimulation, and partial inhibition of the plasma membrane Ca(2+)-ATPase, a Ca(2+)/H(+) exchanger, attenuated pH(cyto) shifts. Repeated stimulus trains mimicking motor patterns generated greater cytosolic acidification (~0.30 pH units). Imaging through the cuticle of intact larvae revealed spontaneous pH(cyto) shifts in presynaptic termini in vivo, similar to those seen in situ during fictive locomotion, indicating that presynaptic pH(cyto) shifts cannot be dismissed as artifacts of ex vivo preparations.
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Affiliation(s)
- Adam J Rossano
- Department of Physiology, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
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GPI-anchored carbonic anhydrase IV displays both intra- and extracellular activity in cRNA-injected oocytes and in mouse neurons. Proc Natl Acad Sci U S A 2013; 110:1494-9. [PMID: 23297198 DOI: 10.1073/pnas.1221213110] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Soluble cytosolic carbonic anhydrases (CAs) are well known to participate in pH regulation of the cytoplasm of mammalian cells. Membrane-bound CA isoforms--such as isoforms IV, IX, XII, XIV, and XV--also catalyze the reversible conversion of carbon dioxide to protons and bicarbonate, but at the extracellular face of the cell membrane. When human CA isoform IV was heterologously expressed in Xenopus oocytes, we observed, by measuring H(+) at the outer face of the cell membrane and in the cytosol with ion-selective microelectrodes, not only extracellular catalytic CA activity but also robust intracellular activity. CA IV expression in oocytes was confirmed by immunocytochemistry, and CA IV activity measured by mass spectrometry. Extra- and intracellular catalytic activity of CA IV could be pharmacologically dissected using benzolamide, the CA inhibitor, which is relatively slowly membrane-permeable. In acute cerebellar slices of mutant mice lacking CA IV, cytosolic H(+) shifts of granule cells following CO(2) removal/addition were significantly slower than in wild-type mice. Our results suggest that membrane-associated CA IV contributes robust catalytic activity intracellularly, and that this activity participates in regulating H(+) dynamics in the cytosol, both in injected oocytes and in mouse neurons.
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Nissou MF, Brocard J, El Atifi M, Guttin A, Andrieux A, Berger F, Issartel JP, Wion D. The transcriptomic response of mixed neuron-glial cell cultures to 1,25-dihydroxyvitamin d3 includes genes limiting the progression of neurodegenerative diseases. J Alzheimers Dis 2013; 35:553-64. [PMID: 23455988 PMCID: PMC3962683 DOI: 10.3233/jad-122005] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Seasonal or chronic vitamin D deficiency and/or insufficiency is highly prevalent in the human population. Receptors for 1,25-dihydroxyvitamin D3, the hormonal metabolite of vitamin D, are found throughout the brain. To provide further information on the role of this hormone on brain function, we analyzed the transcriptomic profiles of mixed neuron-glial cell cultures in response to 1,25-dihydroxyvitamin D3. 1,25-dihydroxyvitamin D3 treatment increases the mRNA levels of 27 genes by at least 1.9 fold. Among them, 17 genes were related to neurodegenerative and psychiatric diseases, or brain morphogenesis. Notably, 10 of these genes encode proteins potentially limiting the progression of Alzheimer's disease. These data provide support for a role of 1,25-dihydroxyvitamin D3 in brain disease prevention. The possible consequences of circannual or chronic vitamin D insufficiencies on a tissue with a low regenerative potential such as the brain should be considered.
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Affiliation(s)
- Marie-France Nissou
- GIN, Grenoble Institut des Neurosciences
INSERM : U836Université Joseph Fourier - Grenoble ICHU GrenobleCEA : DSV/IRTSVUJF - Site Santé La Tronche BP 170 38042 Grenoble Cedex 9, FR
| | - Jacques Brocard
- GIN, Grenoble Institut des Neurosciences
INSERM : U836Université Joseph Fourier - Grenoble ICHU GrenobleCEA : DSV/IRTSVUJF - Site Santé La Tronche BP 170 38042 Grenoble Cedex 9, FR
| | - Michèle El Atifi
- GIN, Grenoble Institut des Neurosciences
INSERM : U836Université Joseph Fourier - Grenoble ICHU GrenobleCEA : DSV/IRTSVUJF - Site Santé La Tronche BP 170 38042 Grenoble Cedex 9, FR
| | - Audrey Guttin
- GIN, Grenoble Institut des Neurosciences
INSERM : U836Université Joseph Fourier - Grenoble ICHU GrenobleCEA : DSV/IRTSVUJF - Site Santé La Tronche BP 170 38042 Grenoble Cedex 9, FR
| | - Annie Andrieux
- GIN, Grenoble Institut des Neurosciences
INSERM : U836Université Joseph Fourier - Grenoble ICHU GrenobleCEA : DSV/IRTSVUJF - Site Santé La Tronche BP 170 38042 Grenoble Cedex 9, FR
- GPC-GIN, Groupe Physiopathologie du Cytosquelette
INSERM : U836CEA : DSV/IRTSV/GPCUniversité Joseph Fourier - Grenoble IUJF - Site Santé La Tronche BP 170 38042 Grenoble Cedex 9, FR
| | - François Berger
- GIN, Grenoble Institut des Neurosciences
INSERM : U836Université Joseph Fourier - Grenoble ICHU GrenobleCEA : DSV/IRTSVUJF - Site Santé La Tronche BP 170 38042 Grenoble Cedex 9, FR
| | - Jean-Paul Issartel
- GIN, Grenoble Institut des Neurosciences
INSERM : U836Université Joseph Fourier - Grenoble ICHU GrenobleCEA : DSV/IRTSVUJF - Site Santé La Tronche BP 170 38042 Grenoble Cedex 9, FR
| | - Didier Wion
- GIN, Grenoble Institut des Neurosciences
INSERM : U836Université Joseph Fourier - Grenoble ICHU GrenobleCEA : DSV/IRTSVUJF - Site Santé La Tronche BP 170 38042 Grenoble Cedex 9, FR
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Hailey DW, Roberts B, Owens KN, Stewart AK, Linbo T, Pujol R, Alper SL, Rubel EW, Raible DW. Loss of Slc4a1b chloride/bicarbonate exchanger function protects mechanosensory hair cells from aminoglycoside damage in the zebrafish mutant persephone. PLoS Genet 2012; 8:e1002971. [PMID: 23071446 PMCID: PMC3469417 DOI: 10.1371/journal.pgen.1002971] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2012] [Accepted: 08/08/2012] [Indexed: 11/19/2022] Open
Abstract
Mechanosensory hair cell death is a leading cause of hearing and balance disorders in the human population. Hair cells are remarkably sensitive to environmental insults such as excessive noise and exposure to some otherwise therapeutic drugs. However, individual responses to damaging agents can vary, in part due to genetic differences. We previously carried out a forward genetic screen using the zebrafish lateral line system to identify mutations that alter the response of larval hair cells to the antibiotic neomycin, one of a class of aminoglycoside compounds that cause hair cell death in humans. The persephone mutation confers resistance to aminoglycosides. 5 dpf homozygous persephone mutants are indistinguishable from wild-type siblings, but differ in their retention of lateral line hair cells upon exposure to neomycin. The mutation in persephone maps to the chloride/bicarbonate exchanger slc4a1b and introduces a single Ser-to-Phe substitution in zSlc4a1b. This mutation prevents delivery of the exchanger to the cell surface and abolishes the ability of the protein to import chloride across the plasma membrane. Loss of function of zSlc4a1b reduces hair cell death caused by exposure to the aminoglycosides neomycin, kanamycin, and gentamicin, and the chemotherapeutic drug cisplatin. Pharmacological block of anion transport with the disulfonic stilbene derivatives DIDS and SITS, or exposure to exogenous bicarbonate, also protects hair cells against damage. Both persephone mutant and DIDS-treated wild-type larvae show reduced uptake of labeled aminoglycosides. persephone mutants also show reduced FM1-43 uptake, indicating a potential impact on mechanotransduction-coupled activity in the mutant. We propose that tight regulation of the ionic environment of sensory hair cells, mediated by zSlc4a1b activity, is critical for their sensitivity to aminoglycoside antibiotics.
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Affiliation(s)
- Dale W. Hailey
- Department of Biological Structure, University of Washington, Seattle, Washington, United States of America
- Virginia Merrill Bloedel Hearing Research Center, University of Washington, Seattle, Washington, United States of America
| | - Brock Roberts
- Department of Biological Structure, University of Washington, Seattle, Washington, United States of America
- Virginia Merrill Bloedel Hearing Research Center, University of Washington, Seattle, Washington, United States of America
| | - Kelly N. Owens
- Department of Biological Structure, University of Washington, Seattle, Washington, United States of America
- Virginia Merrill Bloedel Hearing Research Center, University of Washington, Seattle, Washington, United States of America
- Department of Otolaryngology–Head and Neck Surgery, University of Washington, Seattle, Washington, United States of America
| | - Andrew K. Stewart
- Renal Division and Molecular and Vascular Medicine Unit, Beth Israel Deaconess Medical Center, Boston, Massachusetts, United States of America
| | - Tor Linbo
- Department of Biological Structure, University of Washington, Seattle, Washington, United States of America
| | - Remy Pujol
- Virginia Merrill Bloedel Hearing Research Center, University of Washington, Seattle, Washington, United States of America
- Department of Otolaryngology–Head and Neck Surgery, University of Washington, Seattle, Washington, United States of America
- INSERM Unit 583, Universite de Montpellier, Institut des Neurosciences de Montpellier, Hopital St. Eloi, Montpellier, France
| | - Seth L. Alper
- Renal Division and Molecular and Vascular Medicine Unit, Beth Israel Deaconess Medical Center, Boston, Massachusetts, United States of America
| | - Edwin W. Rubel
- Virginia Merrill Bloedel Hearing Research Center, University of Washington, Seattle, Washington, United States of America
- Department of Otolaryngology–Head and Neck Surgery, University of Washington, Seattle, Washington, United States of America
| | - David W. Raible
- Department of Biological Structure, University of Washington, Seattle, Washington, United States of America
- Virginia Merrill Bloedel Hearing Research Center, University of Washington, Seattle, Washington, United States of America
- * E-mail:
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Tolvanen MEE, Ortutay C, Barker HR, Aspatwar A, Patrikainen M, Parkkila S. Analysis of evolution of carbonic anhydrases IV and XV reveals a rich history of gene duplications and a new group of isozymes. Bioorg Med Chem 2012; 21:1503-10. [PMID: 23022279 DOI: 10.1016/j.bmc.2012.08.060] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2012] [Revised: 08/23/2012] [Accepted: 08/31/2012] [Indexed: 01/09/2023]
Abstract
Carbonic anhydrase (CA) isozymes CA IV and CA XV are anchored on the extracellular cell surface via glycosylphosphatidylinositol (GPI) linkage. Analysis of evolution of these isozymes in vertebrates reveals an additional group of GPI-linked CAs, CA XVII, which has been lost in mammals. Our work resolves nomenclature issues in GPI-linked fish CAs. Review of expression data brings forth previously unreported tissue and cancer types in which human CA IV is expressed. Analysis of collective glycosylation patterns of GPI-linked CAs suggests functionally important regions on the protein surface.
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Affiliation(s)
- Martti E E Tolvanen
- Institute of Biomedical Technology, University of Tampere, Finland and BioMediTech, FI-33014 Tampere, Finland.
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Imtaiyaz Hassan M, Shajee B, Waheed A, Ahmad F, Sly WS. Structure, function and applications of carbonic anhydrase isozymes. Bioorg Med Chem 2012; 21:1570-82. [PMID: 22607884 DOI: 10.1016/j.bmc.2012.04.044] [Citation(s) in RCA: 160] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2012] [Revised: 04/02/2012] [Accepted: 04/21/2012] [Indexed: 01/16/2023]
Abstract
The carbonic anhydrases enzymes (CAs, EC 4.2.1.1) are zinc containing metalloproteins, which efficiently catalyse the reversible conversion of carbon dioxide to bicarbonate and release proton. These enzymes are essentially important for biological system and play several important physiological and patho-physiological functions. There are 16 different alpha-carbonic anhydrase isoforms studied, differing widely in their cellular localization and biophysical properties. The catalytic domains of all CAs possess a conserved tertiary structure fold, with predominately β-strands. We performed an extensive analysis of all 16 mammalian CAs for its structure and function in order to establish a structure-function relationship. CAs have been a potential therapeutic target for many diseases. Sulfonamides are considered as a strong and specific inhibitor of CA, and are being used as diuretics, anti-glaucoma, anti-epileptic, anti-ulcer agents. Currently CA inhibitors are widely used as a drug for the treatment of neurological disorders, anti-glaucoma drugs, anti-cancer, or anti-obesity agents. Here we tried to emphasize how CAs can be used for drug discovery, design and screening. Furthermore, we discussed the role of CA in carbon capture, carbon sensor and metabolon. We hope this review provide many useful information on structure, function, mechanism, and applications of CAs in various discipline.
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Affiliation(s)
- Md Imtaiyaz Hassan
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, Jamia Nagar, New Delhi 110025, India.
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Sherman TA, Rongali SC, Matthews TA, Pfeiffer J, Nehrke K. Identification of a nuclear carbonic anhydrase in Caenorhabditis elegans. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2012; 1823:808-17. [PMID: 22245567 DOI: 10.1016/j.bbamcr.2011.12.014] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2011] [Revised: 12/01/2011] [Accepted: 12/13/2011] [Indexed: 12/27/2022]
Abstract
BACKGROUND Carbonic anhydrases (CA) catalyze the inter-conversion of CO(2) with HCO(3) and H(+), and are involved in a wide variety of physiologic processes such as anion transport, pH regulation, and water balance. In mammals there are sixteen members of the classical α-type CA family, while the simple genetic model organism Caenorhabditis elegans codes for six αCA isoforms (cah-1 through cah-6). METHODS Fluorescent reporter constructs were used to analyze gene promoter usage, splice variation, and protein localization in transgenic worms. Catalytic activity of recombinant CA proteins was assessed using Hansson's histochemistry. CA's ability to regulate pH as a function of CO(2) and HCO(3) was measured using dynamic fluorescent imaging of genetically-targeted biosensors. RESULTS Each of the six CA genes was found to be expressed in a distinct repertoire of cell types. Surprisingly, worms also expressed a catalytically-active CA splice variant, cah-4a, in which an alternative first exon targeted the protein to the nucleus. Cah-4a expression was restricted mainly to the nervous system, where it was found in nearly all neurons, and recombinant CAH-4A protein could regulate pH in the nucleus. CONCLUSIONS In addition to establishing C. elegans as a platform for studying αCA function, this is the first example of a nuclear-targeted αCA in any organism to date. GENERAL SIGNIFICANCE A classical αCA isoform is targeted exclusively to the nucleus where its activity may impact nuclear physiologic and pathophysiologic responses.
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Affiliation(s)
- Teresa A Sherman
- Department of Medicine, University of Rochester Medical Center, Rochester, NY, USA
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Adijanto J, Philp NJ. The SLC16A family of monocarboxylate transporters (MCTs)--physiology and function in cellular metabolism, pH homeostasis, and fluid transport. CURRENT TOPICS IN MEMBRANES 2012. [PMID: 23177990 DOI: 10.1016/b978-0-12-394316-3.00009-0] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The SLC16A family of monocarboxylate transporters (MCTs) is composed of 14 members. MCT1 through MCT4 (MCTs 1-4) are H(+)-coupled monocarboxylate transporters, MCT8 and MCT10 transport thyroid hormone and aromatic amino acids, while the substrate specificity and function of other MCTs have yet to be determined. The focus of this review is on MCTs 1-4 because their role in lactate transport is intrinsically linked to cellular metabolism in various biological systems, including skeletal muscle, brain, retina, and testis. Although MCTs 1-4 all transport lactate, they differ in their transport kinetics and vary in tissue and subcellular distribution, where they facilitate "lactate-shuttling" between glycolytic and oxidative cells within tissues and across blood-tissue barriers. However, the role of MCTs 1-4 is not confined to cellular metabolism. By interacting with bicarbonate transport proteins and carbonic anhydrases, MCTs participate in the regulation of pH homeostasis and fluid transport in renal proximal tubule and corneal endothelium, respectively. Here, we provide a comprehensive review of MCTs 1-4, linking their cellular distribution to their functions in various parts of the human body, so that we can better understand the physiological roles of MCTs at the systemic level.
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Affiliation(s)
- Jeffrey Adijanto
- Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, PA, USA.
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Vargas LA, Alvarez BV. Carbonic anhydrase XIV in the normal and hypertrophic myocardium. J Mol Cell Cardiol 2011; 52:741-52. [PMID: 22227327 DOI: 10.1016/j.yjmcc.2011.12.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/11/2011] [Revised: 11/21/2011] [Accepted: 12/14/2011] [Indexed: 01/20/2023]
Abstract
Two AE3 transcripts, full-length (AE3fl) and cardiac (AE3c) are expressed in the heart. AE3 catalyzes electroneutral Cl(-)/HCO(3)(-) exchange across cardiomyocyte sarcolemma. AE proteins associate with carbonic anhydrases (CA), including CAII and CAIV, forming a HCO(3)(-) transport metabolon (BTM), increasing HCO(3)(-) fluxes and regulating cardiomyocytes pH. CAXIV, which is also expressed in the heart's sarcolemma, is a transmembrane enzyme with an extracellular catalytic domain. Herein, AE3/CAXIV physical association was examined by coimmunoprecipitation using rodent heart lysates. CAXIV immunoprecipitated with anti-AE3 antibody and both AE3fl and AE3c were reciprocally immunoprecipitated using anti-CAXIV antibody, indicating AE3fl-AE3c/CAXIV interaction in the myocardium. Coimmunoprecipitation experiments on heart lysates from a mouse with targeted disruption of the ae3 gene, failed to pull down AE3 with the CAXIV antibody. Confocal images demonstrated colocalization of CAXIV and AE3 in mouse ventricular myocytes. Functional association of AE3fl and CAXIV was examined in isolated hypertrophic rat cardiomyocytes, using fluorescence measurements of BCECF to monitor cytosolic pH. Hypertrophic cardiomyocytes of spontaneously hypertensive rats (SHR) presented elevated myocardial AE-mediated Cl(-)/HCO(3)(-) exchange activity (J(HCO3-) mM.min(-1)) compared to normal (Wistar) rats (7.5±1.3, n=4 versus 2.9±0.1, n=6, respectively). AE3fl, AE3c, CAII, CAIV, and CAIX protein expressions were similar in SHR and Wistar rat hearts. However, immunoblots revealed a twofold increase of CAXIV protein expression in the SHR myocardium compared to normal hearts (n=11). Furthermore, the CA-inhibitor, benzolamide, neutralized the stimulatory effect of extracellular CA on AE3 transport activity (3.7±1.5, n=3), normalizing AE3-dependent HCO(3)(-) fluxes in SHR. CAXIV/AE3 interaction constitutes an extracellular component of a BTM which potentiates AE3-mediated HCO(3)(-) transport in the heart. Increased CAXIV expression and consequent AE3/CAXIV complex formation would render AE3 hyperactive in the SHR heart.
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Affiliation(s)
- Lorena A Vargas
- Centro de Investigaciones Cardiovasculares, Consejo Nacional de Investigaciones Científicas y Técnicas, Facultad de Ciencias Médicas, Universidad Nacional de La Plata, 1900 La Plata, Argentina
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Ravera S, Pepe IM, Calzia D, Morelli A, Panfoli I. Extremely low-frequency electromagnetic fields affect lipid-linked carbonic anhydrase. Electromagn Biol Med 2011; 30:67-73. [PMID: 21591890 DOI: 10.3109/15368378.2011.566770] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
In the last years, the effect of extremely low-frequency electromagnetic fields (ELF-EMF) on the activity of different enzymes were investigated. Only the membrane-anchored enzymes did decrease their activity, up to 50%. In this work, the effect of ELF-EMF on bovine lung membrane carbonic anhydrase (CA) were studied. Carbonic anhydrases are a family of 14 zinc-containing isozymes catalyzing the reversible reaction: CO(2)+H(2)O = HCO(3)(- )+H(+). CA differ in catalytic activity and subcellular localization. CA IV, IX, XII, XIV, and XV are membrane bound. In particular, CA IV, which is expressed in the lung, is glycosyl phosphatidyl inositol-linked to the membrane, therefore it was a candidate to inhibition by ELF-EMF. Exposure to the membranes to a field of 75 Hz frequency and different amplitudes caused CA activity to a reproducible decrease in enzymatic activity by 17% with a threshold of about 0.74 mT. The decrease in enzymatic activity was independent of the time of permanence in the field and was completely reversible. When the source of enzyme was solubilized with Triton, the field lost its effect on CA enzymatic activity, suggesting a crucial role of the membrane, as well as of the particular linkage of the enzyme to it, in determining the conditions for CA inactivation. Results are discussed in terms of the possible physiologic effects of CA inhibition in target organs.
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Affiliation(s)
- Silvia Ravera
- Department of Biology, University of Genoa, Genova, Italy.
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Baghdasaryan A, Claudel T, Gumhold J, Silbert D, Adorini L, Roda A, Vecchiotti S, Gonzalez FJ, Schoonjans K, Strazzabosco M, Fickert P, Trauner M. Dual farnesoid X receptor/TGR5 agonist INT-767 reduces liver injury in the Mdr2-/- (Abcb4-/-) mouse cholangiopathy model by promoting biliary HCO⁻₃ output. Hepatology 2011; 54:1303-12. [PMID: 22006858 PMCID: PMC3744065 DOI: 10.1002/hep.24537] [Citation(s) in RCA: 170] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
UNLABELLED Chronic cholangiopathies have limited therapeutic options and represent an important indication for liver transplantation. The nuclear farnesoid X receptor (FXR) and the membrane G protein-coupled receptor, TGR5, regulate bile acid (BA) homeostasis and inflammation. Therefore, we hypothesized that activation of FXR and/or TGR5 could ameliorate liver injury in Mdr2(-/-) (Abcb4(-/-)) mice, a model of chronic cholangiopathy. Hepatic inflammation, fibrosis, as well as bile secretion and key genes of BA homeostasis were addressed in Mdr2(-/-) mice fed either a chow diet or a diet supplemented with the FXR agonist, INT-747, the TGR5 agonist, INT-777, or the dual FXR/TGR5 agonist, INT-767 (0.03% w/w). Only the dual FXR/TGR5 agonist, INT-767, significantly improved serum liver enzymes, hepatic inflammation, and biliary fibrosis in Mdr2(-/-) mice, whereas INT-747 and INT-777 had no hepatoprotective effects. In line with this, INT-767 significantly induced bile flow and biliary HCO 3- output, as well as gene expression of carbonic anhydrase 14, an important enzyme able to enhance HCO 3- transport, in an Fxr-dependent manner. In addition, INT-767 dramatically reduced bile acid synthesis via the induction of ileal Fgf15 and hepatic Shp gene expression, thus resulting in significantly reduced biliary bile acid output in Mdr2(-/-) mice. CONCLUSION This study shows that FXR activation improves liver injury in a mouse model of chronic cholangiopathy by reduction of biliary BA output and promotion of HCO 3--rich bile secretion.
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Affiliation(s)
- Anna Baghdasaryan
- Laboratory of Experimental and Molecular Hepatology, Division of Gastroenterology and Hepatology, Department of Internal Medicine, Medical University of Graz, Graz, Austria
| | - Thierry Claudel
- Laboratory of Experimental and Molecular Hepatology, Division of Gastroenterology and Hepatology, Department of Internal Medicine, Medical University of Graz, Graz, Austria
- Division of Gastroenterology and Hepatology, Department of Internal Medicine III, Medical University of Vienna, Vienna, Austria
| | - Judith Gumhold
- Laboratory of Experimental and Molecular Hepatology, Division of Gastroenterology and Hepatology, Department of Internal Medicine, Medical University of Graz, Graz, Austria
| | - Dagmar Silbert
- Laboratory of Experimental and Molecular Hepatology, Division of Gastroenterology and Hepatology, Department of Internal Medicine, Medical University of Graz, Graz, Austria
| | | | - Aldo Roda
- Laboratory of Bioanalytical and Analytical Chemistry, Department of Pharmaceutical Sciences, Alma Mater Studiorum, University of Bologna, Bologna, Italy
| | - Stefania Vecchiotti
- Laboratory of Bioanalytical and Analytical Chemistry, Department of Pharmaceutical Sciences, Alma Mater Studiorum, University of Bologna, Bologna, Italy
| | - Frank J. Gonzalez
- Laboratory of Metabolism, National Cancer Institute, National Institutes of Health, Bethesda, MD
| | - Kristina Schoonjans
- Laboratory of Integrative and Systems Physiology, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Mario Strazzabosco
- Department of Internal Medicine, Section of Digestive Diseases, Yale University School of Medicine, New Haven, CT
- Department of Clinical Medicine and Prevention, University of Milan-Bicocca, Milan, Milan, Italy
| | - Peter Fickert
- Laboratory of Experimental and Molecular Hepatology, Division of Gastroenterology and Hepatology, Department of Internal Medicine, Medical University of Graz, Graz, Austria
| | - Michael Trauner
- Laboratory of Experimental and Molecular Hepatology, Division of Gastroenterology and Hepatology, Department of Internal Medicine, Medical University of Graz, Graz, Austria
- Division of Gastroenterology and Hepatology, Department of Internal Medicine III, Medical University of Vienna, Vienna, Austria
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Preemptive regulation of intracellular pH in hippocampal neurons by a dual mechanism of depolarization-induced alkalinization. J Neurosci 2011; 31:6997-7004. [PMID: 21562261 DOI: 10.1523/jneurosci.6088-10.2011] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Numerous studies have documented the mechanisms that regulate intracellular pH (pH(i)) in hippocampal neurons in response to an acid load. Here, we studied the response of pH(i) to depolarization in cultured hippocampal neurons. Elevation of external K+ (6-30 mm) elicited an acid transient followed by a large net alkaline shift. Similar responses were observed in acutely dissociated hippocampal neurons. In Ca2+ -free media, the acid response was curtailed and the alkaline shift enhanced. DIDS blocked the alkaline response and revealed a prolonged underlying acidification that was highly dependent on Ca2+ entry. Similar alkaline responses could be elicited by AMPA, indicating that this rise in pH(i) was a depolarization-induced alkalinization (DIA). The DIA was found to consist of Cl- -dependent and Cl- -independent components, each accounting for approximately one-half of the peak amplitude. The Cl- -independent component was postulated to arise from operation of the electrogenic Na+ -HCO3- cotransporter NBCe1. Quantitative PCR and single-cell multiplex reverse transcription-PCR demonstrated message for NBCe1 in our hippocampal neurons. In neurons cultured from Slc4a4 knock-out (KO) mice, the DIA was reduced by approximately one-half compared with wild type, suggesting that NBCe1 was responsible for the Cl- -independent DIA. In Slc4a4 KO neurons, the remaining DIA was virtually abolished in Cl- -free media. These data demonstrate that DIA of hippocampal neurons occurs via NBCe1, and a parallel DIDS-sensitive, Cl- -dependent mechanism. Our results indicate that, by activating net acid extrusion in response to depolarization, hippocampal neurons can preempt a large, prolonged, Ca2+ -dependent acidosis.
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Perrin RJ, Craig-Schapiro R, Malone JP, Shah AR, Gilmore P, Davis AE, Roe CM, Peskind ER, Li G, Galasko DR, Clark CM, Quinn JF, Kaye JA, Morris JC, Holtzman DM, Townsend RR, Fagan AM. Identification and validation of novel cerebrospinal fluid biomarkers for staging early Alzheimer's disease. PLoS One 2011; 6:e16032. [PMID: 21264269 PMCID: PMC3020224 DOI: 10.1371/journal.pone.0016032] [Citation(s) in RCA: 125] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2010] [Accepted: 12/03/2010] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND Ideally, disease modifying therapies for Alzheimer disease (AD) will be applied during the 'preclinical' stage (pathology present with cognition intact) before severe neuronal damage occurs, or upon recognizing very mild cognitive impairment. Developing and judiciously administering such therapies will require biomarker panels to identify early AD pathology, classify disease stage, monitor pathological progression, and predict cognitive decline. To discover such biomarkers, we measured AD-associated changes in the cerebrospinal fluid (CSF) proteome. METHODS AND FINDINGS CSF samples from individuals with mild AD (Clinical Dementia Rating [CDR] 1) (n = 24) and cognitively normal controls (CDR 0) (n = 24) were subjected to two-dimensional difference-in-gel electrophoresis. Within 119 differentially-abundant gel features, mass spectrometry (LC-MS/MS) identified 47 proteins. For validation, eleven proteins were re-evaluated by enzyme-linked immunosorbent assays (ELISA). Six of these assays (NrCAM, YKL-40, chromogranin A, carnosinase I, transthyretin, cystatin C) distinguished CDR 1 and CDR 0 groups and were subsequently applied (with tau, p-tau181 and Aβ42 ELISAs) to a larger independent cohort (n = 292) that included individuals with very mild dementia (CDR 0.5). Receiver-operating characteristic curve analyses using stepwise logistic regression yielded optimal biomarker combinations to distinguish CDR 0 from CDR>0 (tau, YKL-40, NrCAM) and CDR 1 from CDR<1 (tau, chromogranin A, carnosinase I) with areas under the curve of 0.90 (0.85-0.94 95% confidence interval [CI]) and 0.88 (0.81-0.94 CI), respectively. CONCLUSIONS Four novel CSF biomarkers for AD (NrCAM, YKL-40, chromogranin A, carnosinase I) can improve the diagnostic accuracy of Aβ42 and tau. Together, these six markers describe six clinicopathological stages from cognitive normalcy to mild dementia, including stages defined by increased risk of cognitive decline. Such a panel might improve clinical trial efficiency by guiding subject enrollment and monitoring disease progression. Further studies will be required to validate this panel and evaluate its potential for distinguishing AD from other dementing conditions.
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Affiliation(s)
- Richard J Perrin
- Division of Neuropathology, Washington University School of Medicine, St. Louis, Missouri, United States of America.
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Goebel M, Stengel A, Lambrecht NWG, Sachs G. Selective gene expression by rat gastric corpus epithelium. Physiol Genomics 2010; 43:237-54. [PMID: 21177383 DOI: 10.1152/physiolgenomics.00193.2010] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
The gastrointestinal (GI) tract is divided into several segments that have distinct functional properties, largely absorptive. The gastric corpus is the only segment thought of as largely secretory. Microarray hybridization of the gastric corpus mucosal epithelial cells was used to compare gene expression with other segments of the columnar GI tract followed by statistical data subtraction to identify genes selectively expressed by the rat gastric corpus mucosa. This provides a means of identifying less obvious specific functions of the corpus in addition to its secretion-related genes. For example, important properties found by this GI tract comparative transcriptome reflect the energy demand of acid secretion, a role in lipid metabolism, the large variety of resident neuroendocrine cells, responses to damaging agents and transcription factors defining differentiation of its epithelium. In terms of overlap of gastric corpus genes with the rest of the GI tract, the distal small bowel appears to express many of the gastric corpus genes in contrast to proximal small and large bowel. This differential map of gene expression by the gastric corpus epithelium will allow a more detailed description of major properties of the gastric corpus and may lead to the discovery of gastric corpus cell differentiation genes and those mis-regulated in gastric carcinomas.
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Affiliation(s)
- M Goebel
- Department of Medicine, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, USA
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Davis RA, Innocenti A, Poulsen SA, Supuran CT. Carbonic anhydrase inhibitors. Identification of selective inhibitors of the human mitochondrial isozymes VA and VB over the cytosolic isozymes I and II from a natural product-based phenolic library. Bioorg Med Chem 2010; 18:14-8. [DOI: 10.1016/j.bmc.2009.11.021] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2009] [Revised: 10/29/2009] [Accepted: 11/07/2009] [Indexed: 12/21/2022]
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Chiche J, Brahimi-Horn MC, Pouysségur J. Tumour hypoxia induces a metabolic shift causing acidosis: a common feature in cancer. J Cell Mol Med 2009; 14:771-94. [PMID: 20015196 PMCID: PMC3823111 DOI: 10.1111/j.1582-4934.2009.00994.x] [Citation(s) in RCA: 459] [Impact Index Per Article: 30.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Maintenance of cellular pH homeostasis is fundamental to life. A number of key intracellular pH (pHi) regulating systems including the Na+/H+ exchangers, the proton pump, the monocarboxylate transporters, the HCO3− transporters and exchangers and the membrane-associated and cytosolic carbonic anhydrases cooperate in maintaining a pHi that is permissive for cell survival. A common feature of tumours is acidosis caused by hypoxia (low oxygen tension). In addition to oncogene activation and transformation, hypoxia is responsible for inducing acidosis through a shift in cellular metabolism that generates a high acid load in the tumour microenvironment. However, hypoxia and oncogene activation also allow cells to adapt to the potentially toxic effects of an excess in acidosis. Hypoxia does so by inducing the activity of a transcription factor the hypoxia-inducible factor (HIF), and particularly HIF-1, that in turn enhances the expression of a number of pHi-regulating systems that cope with acidosis. In this review, we will focus on the characterization and function of some of the hypoxia-inducible pH-regulating systems and their induction by hypoxic stress. It is essential to understand the fundamentals of pH regulation to meet the challenge consisting in targeting tumour metabolism and acidosis as an anti-tumour approach. We will summarize strategies that take advantage of intracellular and extracellular pH regulation to target the primary tumour and metastatic growth, and to turn around resistance to chemotherapy and radiotherapy.
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Affiliation(s)
- Johanna Chiche
- Institute of Developmental Biology and Cancer Research, University of Nice, CNRS UMR, Centre A. Lacassagne, Nice, France
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Casey JR, Sly WS, Shah GN, Alvarez BV. Bicarbonate homeostasis in excitable tissues: role of AE3 Cl-/HCO3- exchanger and carbonic anhydrase XIV interaction. Am J Physiol Cell Physiol 2009; 297:C1091-102. [PMID: 19692653 DOI: 10.1152/ajpcell.00177.2009] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Bicarbonate transport and metabolism are key elements of normal cellular function. Two alternate transcripts of anion exchanger 3 (AE3), full-length (AE3fl) and cardiac (AE3c), are expressed in central nervous system (CNS), where AE3 catalyzes electroneutral Cl(-)/HCO(3)(-) exchange across the plasma membrane of neuronal and glial cells of CNS. Anion exchanger isoforms, AE3fl and AE3c, associate with the carbonic anhydrases (CA) CAII and CAIV, forming a HCO(3)(-) transport metabolon, to maximize HCO(3)(-) flux across the plasma membrane. CAXIV, with catalytic domain anchored to the extracellular surface, is also expressed in CNS. Here physical association of AE3 and CAXIV was examined by coimmunoprecipitation experiments, using mouse brain and retinal lysates. CAXIV immunoprecipitated with anti-AE3 antibody, and both AE3 isoforms were immunoprecipitated using anti-CAXIV antibody, indicating CAXIV and AE3 interaction in the CNS. Confocal images revealed colocalization of CAXIV and AE3 in Müller and horizontal cells, in the mouse retina. Cl(-)/HCO(3)(-) exchange activity of AE3fl was investigated in transiently transfected human embryonic kidney 293 cells, using intracellular fluorescence measurements of BCECF, to monitor intracellular pH. CAXIV increased the rate of AE3fl-mediated HCO(3)(-) transport by up to 120%, which was suppressed by the CA inhibitor acetazolamide. Association of AE3 and CAXIV may represent a mechanism to enhance disposal of waste CO(2) and to balance pH in excitable tissues.
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Affiliation(s)
- Joseph R Casey
- Department of Physiology and Department of Biochemistry, Membrane Protein Research Group, University of Alberta, Edmonton, Canada
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