1
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Rose CR, Verkhratsky A. Sodium homeostasis and signalling: The core and the hub of astrocyte function. Cell Calcium 2024; 117:102817. [PMID: 37979342 DOI: 10.1016/j.ceca.2023.102817] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2023] [Accepted: 10/20/2023] [Indexed: 11/20/2023]
Abstract
Neuronal activity and neurochemical stimulation trigger spatio-temporal changes in the cytoplasmic concentration of Na+ ions in astrocytes. These changes constitute the substrate for Na+ signalling and are fundamental for astrocytic excitability. Astrocytic Na+ signals are generated by Na+ influx through neurotransmitter transporters, with primary contribution of glutamate transporters, and through cationic channels; whereas recovery from Na+ transients is mediated mainly by the plasmalemmal Na+/K+ ATPase. Astrocytic Na+ signals regulate the activity of plasmalemmal transporters critical for homeostatic function of astrocytes, thus providing real-time coordination between neuronal activity and astrocytic support.
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Affiliation(s)
- Christine R Rose
- Institute of Neurobiology, Faculty of Mathematics and Natural Sciences, Heinrich Heine University Düsseldorf, 40225 Düsseldorf, Germany.
| | - Alexej Verkhratsky
- Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, M13 9PT, United Kingdom; Achucarro Centre for Neuroscience, IKERBASQUE, Basque Foundation for Science, 48011 Bilbao, Spain; Department of Forensic Analytical Toxicology, School of Forensic Medicine, China Medical University, Shenyang, China; International Collaborative Center on Big Science Plan for Purinergic Signaling, Chengdu University of Traditional Chinese Medicine, Chengdu, China; Department of Stem Cell Biology, State Research Institute Centre for Innovative Medicine, LT-01102, Vilnius, Lithuania.
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2
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Maiolo L, Guarino V, Saracino E, Convertino A, Melucci M, Muccini M, Ambrosio L, Zamboni R, Benfenati V. Glial Interfaces: Advanced Materials and Devices to Uncover the Role of Astroglial Cells in Brain Function and Dysfunction. Adv Healthc Mater 2021; 10:e2001268. [PMID: 33103375 DOI: 10.1002/adhm.202001268] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2020] [Revised: 10/06/2020] [Indexed: 12/13/2022]
Abstract
Research over the past four decades has highlighted the importance of certain brain cells, called glial cells, and has moved the neurocentric vision of structure, function, and pathology of the nervous system toward a more holistic perspective. In this view, the demand for technologies that are able to target and both selectively monitor and control glial cells is emerging as a challenge across neuroscience, engineering, chemistry, and material science. Frequently neglected or marginally considered as a barrier to be overcome between neural implants and neuronal targets, glial cells, and in particular astrocytes, are increasingly considered as active players in determining the outcomes of device implantation. This review provides a concise overview not only of the previously established but also of the emerging physiological and pathological roles of astrocytes. It also critically discusses the most recent advances in biomaterial interfaces and devices that interact with glial cells and thus have enabled scientists to reach unprecedented insights into the role of astroglial cells in brain function and dysfunction. This work proposes glial interfaces and glial engineering as multidisciplinary fields that have the potential to enable significant advancement of knowledge surrounding cognitive function and acute and chronic neuropathologies.
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Affiliation(s)
- Luca Maiolo
- Consiglio Nazionale delle Ricerche Istituto per la Microelettronica e i Microsistemi Via del Fosso del Cavaliere n.100 Roma 00133 Italy
| | - Vincenzo Guarino
- Consiglio Nazionale delle Ricerche Istituto per i Polimeri Compositi e Biomateriali Viale J.F. Kennedy 54, Mostra d'Oltremare, Pad 20 Napoli 80125 Italy
| | - Emanuela Saracino
- Consiglio Nazionale delle Ricerche Istituto per la Sintesi Organica e la Fotoreattività via P. Gobetti 101 Bologna 40129 Italy
| | - Annalisa Convertino
- Consiglio Nazionale delle Ricerche Istituto per la Microelettronica e i Microsistemi Via del Fosso del Cavaliere n.100 Roma 00133 Italy
| | - Manuela Melucci
- Consiglio Nazionale delle Ricerche Istituto per la Sintesi Organica e la Fotoreattività via P. Gobetti 101 Bologna 40129 Italy
| | - Michele Muccini
- Consiglio Nazionale delle Ricerche Istituto per la Studio dei Materiali Nanostrutturati via P. Gobetti 101 Bologna 40129 Italy
| | - Luigi Ambrosio
- Consiglio Nazionale delle Ricerche Istituto per i Polimeri Compositi e Biomateriali Viale J.F. Kennedy 54, Mostra d'Oltremare, Pad 20 Napoli 80125 Italy
| | - Roberto Zamboni
- Consiglio Nazionale delle Ricerche Istituto per la Sintesi Organica e la Fotoreattività via P. Gobetti 101 Bologna 40129 Italy
| | - Valentina Benfenati
- Consiglio Nazionale delle Ricerche Istituto per la Sintesi Organica e la Fotoreattività via P. Gobetti 101 Bologna 40129 Italy
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3
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Boente-Juncal A, Raposo-García S, Costas C, Louzao MC, Vale C, Botana LM. Partial Blockade of Human Voltage-Dependent Sodium Channels by the Marine Toxins Azaspiracids. Chem Res Toxicol 2020; 33:2593-2604. [DOI: 10.1021/acs.chemrestox.0c00216] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- Andrea Boente-Juncal
- Departamento de Farmacologı́a, Farmacia y Tecnologı́a Farmacéutica, Facultade de Veterinaria, Universidade de Santiago de Compostela, Campus Universitario s/n, 27002 Lugo, Spain
| | - Sandra Raposo-García
- Departamento de Farmacologı́a, Farmacia y Tecnologı́a Farmacéutica, Facultade de Veterinaria, Universidade de Santiago de Compostela, Campus Universitario s/n, 27002 Lugo, Spain
| | - Celia Costas
- Departamento de Farmacologı́a, Farmacia y Tecnologı́a Farmacéutica, Facultade de Veterinaria, Universidade de Santiago de Compostela, Campus Universitario s/n, 27002 Lugo, Spain
| | - M. Carmen Louzao
- Departamento de Farmacologı́a, Farmacia y Tecnologı́a Farmacéutica, Facultade de Veterinaria, Universidade de Santiago de Compostela, Campus Universitario s/n, 27002 Lugo, Spain
| | - Carmen Vale
- Departamento de Farmacologı́a, Farmacia y Tecnologı́a Farmacéutica, Facultade de Veterinaria, Universidade de Santiago de Compostela, Campus Universitario s/n, 27002 Lugo, Spain
| | - Luis M. Botana
- Departamento de Farmacologı́a, Farmacia y Tecnologı́a Farmacéutica, Facultade de Veterinaria, Universidade de Santiago de Compostela, Campus Universitario s/n, 27002 Lugo, Spain
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4
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Felix L, Delekate A, Petzold GC, Rose CR. Sodium Fluctuations in Astroglia and Their Potential Impact on Astrocyte Function. Front Physiol 2020; 11:871. [PMID: 32903427 PMCID: PMC7435049 DOI: 10.3389/fphys.2020.00871] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Accepted: 06/29/2020] [Indexed: 12/12/2022] Open
Abstract
Astrocytes are the main cell type responsible for the regulation of brain homeostasis, including the maintenance of ion gradients and neurotransmitter clearance. These processes are tightly coupled to changes in the intracellular sodium (Na+) concentration. While activation of the sodium-potassium-ATPase (NKA) in response to an elevation of extracellular K+ may decrease intracellular Na+, the cotransport of transmitters, such as glutamate, together with Na+ results in an increase in astrocytic Na+. This increase in intracellular Na+ can modulate, for instance, metabolic downstream pathways. Thereby, astrocytes are capable to react on a fast time scale to surrounding neuronal activity via intracellular Na+ fluctuations and adjust energy production to the demand of their environment. Beside the well-documented conventional roles of Na+ signaling mainly mediated through changes in its electrochemical gradient, several recent studies have identified more atypical roles for Na+, including protein interactions leading to changes in their biochemical activity or Na+-dependent regulation of gene expression. In this review, we will address both the conventional as well as the atypical functions of astrocytic Na+ signaling, presenting the role of transporters and channels involved and their implications for physiological processes in the central nervous system (CNS). We will also discuss how these important functions are affected under pathological conditions, including stroke and migraine. We postulate that Na+ is an essential player not only in the maintenance of homeostatic processes but also as a messenger for the fast communication between neurons and astrocytes, adjusting the functional properties of various cellular interaction partners to the needs of the surrounding network.
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Affiliation(s)
- Lisa Felix
- Institute of Neurobiology, Heinrich Heine University Duesseldorf, Duesseldorf, Germany
| | - Andrea Delekate
- German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany
| | - Gabor C Petzold
- German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany.,Division of Vascular Neurology, Department of Neurology, University Hospital Bonn, Bonn, Germany
| | - Christine R Rose
- Institute of Neurobiology, Heinrich Heine University Duesseldorf, Duesseldorf, Germany
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5
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Guo H, Yin A, Ma Y, Fan Z, Tao L, Tang W, Ma Y, Hou W, Cai G, Zhuo L, Zhang J, Li Y, Xiong L. Astroglial N-myc downstream-regulated gene 2 protects the brain from cerebral edema induced by stroke. Glia 2020; 69:281-295. [PMID: 32652708 PMCID: PMC7754347 DOI: 10.1002/glia.23888] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2018] [Revised: 06/16/2020] [Accepted: 06/26/2020] [Indexed: 01/14/2023]
Abstract
Brain edema is a grave complication of brain ischemia and is the main cause of herniation and death. Although astrocytic swelling is the main contributor to cytotoxic edema, the molecular mechanism involved in this process remains elusive. N‐myc downstream‐regulated gene 2 (NDRG2), a well‐studied tumor suppressor gene, is mainly expressed in astrocytes in mammalian brains. Here, we found that NDRG2 deficiency leads to worsened cerebral edema, imbalanced Na+ transfer, and astrocyte swelling after ischemia. We also found that NDRG2 deletion in astrocytes dramatically changed the expression and distribution of aquaporin‐4 and Na+‐K+‐ATPase β1, which are strongly associated with cell polarity, in the ischemic brain. Brain edema and astrocyte swelling were significantly alleviated by rescuing the expression of astrocytic Na+‐K+‐ATPase β1 in NDRG2‐knockout mouse brains. In addition, the upregulation of astrocytic NDRG2 by lentiviral constructs notably attenuated brain edema, astrocytic swelling, and blood–brain barrier destruction. Our results indicate a particular role of NDRG2 in maintaining astrocytic polarization to facilitate Na+ and water transfer balance and to protect the brain from ischemic edema. These findings provide insight into NDRG2 as a therapeutic target in cerebral edema.
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Affiliation(s)
- Hang Guo
- Department of Anesthesiology, The Seventh Medical Center of Chinese PLA General Hospital, Beijing, China.,Department of Anesthesiology and Perioperative Medicine, Xijing Hospital, The Air Force Military Medical University, Xi'an, China
| | - Anqi Yin
- Department of Anesthesiology and Perioperative Medicine, Xijing Hospital, The Air Force Military Medical University, Xi'an, China.,Department of Anesthesiology, Jinling Hospital, Nanjing, China
| | - Yulong Ma
- Anesthesia and Operation Center, The First Medical Center of Chinese PLA General Hospital, Beijing, China
| | - Ze Fan
- Department of Anesthesiology and Perioperative Medicine, Xijing Hospital, The Air Force Military Medical University, Xi'an, China
| | - Liang Tao
- Department of Anesthesiology and Perioperative Medicine, Xijing Hospital, The Air Force Military Medical University, Xi'an, China
| | - Wenhong Tang
- Department of Anesthesiology, The 960th Hospital of PLA, Jinan, China
| | - Yaqun Ma
- Department of Anesthesiology, The Seventh Medical Center of Chinese PLA General Hospital, Beijing, China
| | - Wugang Hou
- Department of Anesthesiology and Perioperative Medicine, Xijing Hospital, The Air Force Military Medical University, Xi'an, China
| | - Guohong Cai
- Institute of Neuroscience, The Air Force Military Medical University, Xi'an, China
| | - Lixia Zhuo
- Department of Anesthesiology & Center for Brain Science, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China
| | - Jian Zhang
- Department of Biochemistry and Molecular Biology, The Air Force Military Medical University, Xi'an, China
| | - Yan Li
- Department of Anesthesiology and Perioperative Medicine, Xijing Hospital, The Air Force Military Medical University, Xi'an, China.,Department of Anesthesiology & Center for Brain Science, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China
| | - Lize Xiong
- Department of Anesthesiology and Perioperative Medicine, Xijing Hospital, The Air Force Military Medical University, Xi'an, China.,Department of Anesthesiology & Translational Research Institute of Brain and Brain-Like Intelligence, Shanghai Fourth People's Hospital, Tongji University School of Medicine, Shanghai, China
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6
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Roles of volume-regulatory anion channels, VSOR and Maxi-Cl, in apoptosis, cisplatin resistance, necrosis, ischemic cell death, stroke and myocardial infarction. CURRENT TOPICS IN MEMBRANES 2019; 83:205-283. [DOI: 10.1016/bs.ctm.2019.03.001] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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7
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Wilson CS, Mongin AA. Cell Volume Control in Healthy Brain and Neuropathologies. CURRENT TOPICS IN MEMBRANES 2018; 81:385-455. [PMID: 30243438 DOI: 10.1016/bs.ctm.2018.07.006] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Regulation of cellular volume is a critical homeostatic process that is intimately linked to ionic and osmotic balance in the brain tissue. Because the brain is encased in the rigid skull and has a very complex cellular architecture, even minute changes in the volume of extracellular and intracellular compartments have a very strong impact on tissue excitability and function. The failure of cell volume control is a major feature of several neuropathologies, such as hyponatremia, stroke, epilepsy, hyperammonemia, and others. There is strong evidence that such dysregulation, especially uncontrolled cell swelling, plays a major role in adverse pathological outcomes. To protect themselves, brain cells utilize a variety of mechanisms to maintain their optimal volume, primarily by releasing or taking in ions and small organic molecules through diverse volume-sensitive ion channels and transporters. In principle, the mechanisms of cell volume regulation are not unique to the brain and share many commonalities with other tissues. However, because ions and some organic osmolytes (e.g., major amino acid neurotransmitters) have a strong impact on neuronal excitability, cell volume regulation in the brain is a surprisingly treacherous process, which may cause more harm than good. This topical review covers the established and emerging information in this rapidly developing area of physiology.
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Affiliation(s)
- Corinne S Wilson
- Department of Neuroscience and Experimental Therapeutics, Albany Medical College, Albany, NY, United States
| | - Alexander A Mongin
- Department of Neuroscience and Experimental Therapeutics, Albany Medical College, Albany, NY, United States; Department of Biophysics and Functional Diagnostics, Siberian State Medical University, Tomsk, Russian Federation
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8
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Abstract
Astrocytes are neural cells of ectodermal, neuroepithelial origin that provide for homeostasis and defense of the central nervous system (CNS). Astrocytes are highly heterogeneous in morphological appearance; they express a multitude of receptors, channels, and membrane transporters. This complement underlies their remarkable adaptive plasticity that defines the functional maintenance of the CNS in development and aging. Astrocytes are tightly integrated into neural networks and act within the context of neural tissue; astrocytes control homeostasis of the CNS at all levels of organization from molecular to the whole organ.
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Affiliation(s)
- Alexei Verkhratsky
- The University of Manchester , Manchester , United Kingdom ; Achúcarro Basque Center for Neuroscience, IKERBASQUE, Basque Foundation for Science , Bilbao , Spain ; Department of Neuroscience, University of the Basque Country UPV/EHU and CIBERNED, Leioa, Spain ; Center for Basic and Translational Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen , Copenhagen , Denmark ; and Center for Translational Neuromedicine, University of Rochester Medical Center , Rochester, New York
| | - Maiken Nedergaard
- The University of Manchester , Manchester , United Kingdom ; Achúcarro Basque Center for Neuroscience, IKERBASQUE, Basque Foundation for Science , Bilbao , Spain ; Department of Neuroscience, University of the Basque Country UPV/EHU and CIBERNED, Leioa, Spain ; Center for Basic and Translational Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen , Copenhagen , Denmark ; and Center for Translational Neuromedicine, University of Rochester Medical Center , Rochester, New York
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9
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Verkhratsky A, Nedergaard M. Physiology of Astroglia. Physiol Rev 2018; 98:239-389. [PMID: 29351512 PMCID: PMC6050349 DOI: 10.1152/physrev.00042.2016] [Citation(s) in RCA: 899] [Impact Index Per Article: 149.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Revised: 03/22/2017] [Accepted: 04/27/2017] [Indexed: 02/07/2023] Open
Abstract
Astrocytes are neural cells of ectodermal, neuroepithelial origin that provide for homeostasis and defense of the central nervous system (CNS). Astrocytes are highly heterogeneous in morphological appearance; they express a multitude of receptors, channels, and membrane transporters. This complement underlies their remarkable adaptive plasticity that defines the functional maintenance of the CNS in development and aging. Astrocytes are tightly integrated into neural networks and act within the context of neural tissue; astrocytes control homeostasis of the CNS at all levels of organization from molecular to the whole organ.
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Affiliation(s)
- Alexei Verkhratsky
- The University of Manchester , Manchester , United Kingdom ; Achúcarro Basque Center for Neuroscience, IKERBASQUE, Basque Foundation for Science , Bilbao , Spain ; Department of Neuroscience, University of the Basque Country UPV/EHU and CIBERNED, Leioa, Spain ; Center for Basic and Translational Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen , Copenhagen , Denmark ; and Center for Translational Neuromedicine, University of Rochester Medical Center , Rochester, New York
| | - Maiken Nedergaard
- The University of Manchester , Manchester , United Kingdom ; Achúcarro Basque Center for Neuroscience, IKERBASQUE, Basque Foundation for Science , Bilbao , Spain ; Department of Neuroscience, University of the Basque Country UPV/EHU and CIBERNED, Leioa, Spain ; Center for Basic and Translational Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen , Copenhagen , Denmark ; and Center for Translational Neuromedicine, University of Rochester Medical Center , Rochester, New York
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10
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Gaitán-Peñas H, Gradogna A, Laparra-Cuervo L, Solsona C, Fernández-Dueñas V, Barrallo-Gimeno A, Ciruela F, Lakadamyali M, Pusch M, Estévez R. Investigation of LRRC8-Mediated Volume-Regulated Anion Currents in Xenopus Oocytes. Biophys J 2017; 111:1429-1443. [PMID: 27705766 PMCID: PMC5052465 DOI: 10.1016/j.bpj.2016.08.030] [Citation(s) in RCA: 85] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Revised: 08/24/2016] [Accepted: 08/26/2016] [Indexed: 12/31/2022] Open
Abstract
Volume-regulated anion channels (VRACs) play an important role in controlling cell volume by opening upon cell swelling. Recent work has shown that heteromers of LRRC8A with other LRRC8 members (B, C, D, and E) form the VRAC. Here, we used Xenopus oocytes as a simple system to study LRRC8 proteins. We discovered that adding fluorescent proteins to the C-terminus resulted in constitutive anion channel activity. Using these constructs, we reproduced previous findings indicating that LRRC8 heteromers mediate anion and osmolyte flux with subunit-dependent kinetics and selectivity. Additionally, we found that LRRC8 heteromers mediate glutamate and ATP flux and that the inhibitor carbenoxolone acts from the extracellular side, binding to probably more than one site. Our results also suggest that the stoichiometry of LRRC8 heteromers is variable, with a number of subunits ≥6, and that the heteromer composition depends on the relative expression of different subunits. The system described here enables easy structure-function analysis of LRRC8 proteins.
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Affiliation(s)
- Héctor Gaitán-Peñas
- Unitat de Fisiología, Departament de Ciències Fisiològiques II, IDIBELL-Universitat de Barcelona, L'Hospitalet de Llobregat, Spain; U-750, CIBERER, ISCIII, Spain
| | | | - Lara Laparra-Cuervo
- ICFO-Institut de Ciències Fotòniques, The Barcelona Institute of Science and Technology, Castelldefels, Spain
| | - Carles Solsona
- Unitat de Neurobiologia, Departament Patologia i Terapèutica Experimental IDIBELL-Universitat de Barcelona, L'Hospitalet de Llobregat
| | - Victor Fernández-Dueñas
- Unitat de Farmacologia, Departament Patologia i Terapèutica Experimental IDIBELL-Universitat de Barcelona, L'Hospitalet de Llobregat
| | - Alejandro Barrallo-Gimeno
- Unitat de Fisiología, Departament de Ciències Fisiològiques II, IDIBELL-Universitat de Barcelona, L'Hospitalet de Llobregat, Spain; U-750, CIBERER, ISCIII, Spain
| | - Francisco Ciruela
- Unitat de Farmacologia, Departament Patologia i Terapèutica Experimental IDIBELL-Universitat de Barcelona, L'Hospitalet de Llobregat
| | - Melike Lakadamyali
- ICFO-Institut de Ciències Fotòniques, The Barcelona Institute of Science and Technology, Castelldefels, Spain
| | | | - Raúl Estévez
- Unitat de Fisiología, Departament de Ciències Fisiològiques II, IDIBELL-Universitat de Barcelona, L'Hospitalet de Llobregat, Spain; U-750, CIBERER, ISCIII, Spain.
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11
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Enger R, Dukefoss DB, Tang W, Pettersen KH, Bjørnstad DM, Helm PJ, Jensen V, Sprengel R, Vervaeke K, Ottersen OP, Nagelhus EA. Deletion of Aquaporin-4 Curtails Extracellular Glutamate Elevation in Cortical Spreading Depression in Awake Mice. Cereb Cortex 2017; 27:24-33. [PMID: 28365776 PMCID: PMC5939213 DOI: 10.1093/cercor/bhw359] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2016] [Revised: 10/25/2016] [Accepted: 10/29/2016] [Indexed: 12/20/2022] Open
Abstract
Cortical spreading depression (CSD) is a phenomenon that challenges the homeostatic mechanisms on which normal brain function so critically depends. Analyzing the sequence of events in CSD holds the potential of providing new insight in the physiological processes underlying normal brain function as well as the pathophysiology of neurological conditions characterized by ionic dyshomeostasis. Here, we have studied the sequential progression of CSD in awake wild-type mice and in mice lacking aquaporin-4 (AQP4) or inositol 1,4,5-triphosphate type 2 receptor (IP3R2). By the use of a novel combination of genetically encoded sensors that a novel combination - an unprecedented temporal and spatial resolution, we show that CSD leads to brisk Ca2+ signals in astrocytes and that the duration of these Ca2+ signals is shortened in the absence of AQP4 but not in the absence of IP3R2. The decrease of the astrocytic, AQP4-dependent Ca2+ signals, coincides in time and space with a decrease in the duration of extracellular glutamate overflow but not with the initial peak of the glutamate release suggesting that in CSD, extracellular glutamate accumulation is extended through AQP4-dependent glutamate release from astrocytes. The present data point to a salient glial contribution to CSD and identify AQP4 as a new target for therapy.
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Affiliation(s)
- Rune Enger
- Department of Neurology, Oslo University Hospital, N-0027 Oslo, Norway
- GliaLab and Letten Centre, Division of Physiology, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, N-0317 Oslo, Norway
| | - Didrik B. Dukefoss
- GliaLab and Letten Centre, Division of Physiology, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, N-0317 Oslo, Norway
| | - Wannan Tang
- GliaLab and Letten Centre, Division of Physiology, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, N-0317 Oslo, Norway
| | - Klas H. Pettersen
- GliaLab and Letten Centre, Division of Physiology, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, N-0317 Oslo, Norway
| | - Daniel M. Bjørnstad
- GliaLab and Letten Centre, Division of Physiology, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, N-0317 Oslo, Norway
| | - P. Johannes Helm
- GliaLab and Letten Centre, Division of Physiology, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, N-0317 Oslo, Norway
| | - Vidar Jensen
- GliaLab and Letten Centre, Division of Physiology, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, N-0317 Oslo, Norway
| | - Rolf Sprengel
- Department of Molecular Neurobiology, Max Planck Institute for Medical Research, D-69120 Heidelberg, Germany
- Max Planck Research Group at the Institute for Anatomy and Cell Biology, Heidelberg University, D-69120 Heidelberg, Germany
| | - Koen Vervaeke
- Division of Physiology, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, N-0317 Oslo, Norway
| | - Ole P. Ottersen
- Division of Anatomy, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, N-0317 Oslo, Norway
| | - Erlend A. Nagelhus
- Department of Neurology, Oslo University Hospital, N-0027 Oslo, Norway
- GliaLab and Letten Centre, Division of Physiology, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, N-0317 Oslo, Norway
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12
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Shuvaev AN, Salmin VV, Kuvacheva NV, Pozhilenkova EA, Morgun AV, Lopatina OL, Salmina AB, Illarioshkin SN. Current advances in cell electrophysiology: applications for the analysis of intercellular communications within the neurovascular unit. Rev Neurosci 2016; 27:365-76. [PMID: 26641963 DOI: 10.1515/revneuro-2015-0047] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Accepted: 10/21/2015] [Indexed: 01/09/2023]
Abstract
Patch clamp is a golden standard for studying (patho)physiological processes affecting membranes of excitable cells. This method is rather labor-intensive and requires well-trained professionals and long-lasting experimental procedures; therefore, accurate designing of the experiments with patch clamp methodology as well as collecting and analyzing the data obtained are essential for the widely spread implementation of this method into the routine research practice. Recently, the method became very prospective not only for the characterization of single excitable cells but also for the detailed assessment of intercellular communication, i.e. within the neurovascular unit. Here, we analyze the main advantages and disadvantages of patch clamp method, with special focus on the tendencies in clamping technique improvement with the help of patch electrodes for the assessment of intercellular communication in the brain.
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13
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Stokum JA, Gerzanich V, Simard JM. Molecular pathophysiology of cerebral edema. J Cereb Blood Flow Metab 2016; 36:513-38. [PMID: 26661240 PMCID: PMC4776312 DOI: 10.1177/0271678x15617172] [Citation(s) in RCA: 357] [Impact Index Per Article: 44.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Revised: 10/21/2015] [Accepted: 10/22/2015] [Indexed: 12/25/2022]
Abstract
Advancements in molecular biology have led to a greater understanding of the individual proteins responsible for generating cerebral edema. In large part, the study of cerebral edema is the study of maladaptive ion transport. Following acute CNS injury, cells of the neurovascular unit, particularly brain endothelial cells and astrocytes, undergo a program of pre- and post-transcriptional changes in the activity of ion channels and transporters. These changes can result in maladaptive ion transport and the generation of abnormal osmotic forces that, ultimately, manifest as cerebral edema. This review discusses past models and current knowledge regarding the molecular and cellular pathophysiology of cerebral edema.
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Affiliation(s)
- Jesse A Stokum
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, USA
| | - Volodymyr Gerzanich
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, USA
| | - J Marc Simard
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, USA Department of Pathology, University of Maryland School of Medicine, Baltimore, USA Department of Physiology, University of Maryland School of Medicine, Baltimore, USA
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14
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Lakomá J, Donadio V, Liguori R, Caprini M. Characterization of Human Dermal Fibroblasts in Fabry Disease. J Cell Physiol 2016; 231:192-203. [PMID: 26058984 DOI: 10.1002/jcp.25072] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2015] [Accepted: 06/05/2015] [Indexed: 12/14/2022]
Abstract
Fabry disease (FD) is a hereditary X-linked metabolic lysosomal storage disorder due to insufficient amounts or a complete lack of the lysosomal enzyme α-galactosidase A (α-GalA). The loss of α-GalA activity leads to an abnormal accumulation of globotriaosylcerami (Gb3) in lysosomes and other cellular components of different tissues and cell types, affecting the cell function. However, whether these biochemical alterations also modify functional processes associated to the cell mitotic ability is still unknown. The goal of the present study was to characterize lineages of human dermal fibroblasts (HDFs) of FD patients and healthy controls focusing on Gb3 accumulation, expression of chloride channels that regulate proliferation, and proliferative activity. The biochemical and functional analyses indicate the existence of quantitative differences in some but not all the parameters of cytoskeletal organization, proliferation, and differentiation processes.
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Affiliation(s)
- Jarmila Lakomá
- Laboratory of Human General Physiology, Department of Pharmacy Biotechnology FaBiT, University of Bologna, Bologna, Italy
| | - Vincenzo Donadio
- IRCCS Institute of Neurological Sciences, AUSL Bologna, Bologna, Italy
| | - Rocco Liguori
- IRCCS Institute of Neurological Sciences, AUSL Bologna, Bologna, Italy.,Department of Biomedical and Neuromotor Sciences (DIBINEM), University of Bologna, Bologna, Italy
| | - Marco Caprini
- Laboratory of Human General Physiology, Department of Pharmacy Biotechnology FaBiT, University of Bologna, Bologna, Italy
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15
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Fugelli K. Effects of sodium ions on rat thyrocyte (FRTL-5 cells) swelling- and thyrotropin-activated taurine efflux dependent on cAMP and Epac. Amino Acids 2015; 48:763-777. [PMID: 26553454 DOI: 10.1007/s00726-015-2124-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2015] [Accepted: 10/26/2015] [Indexed: 11/25/2022]
Abstract
Cellular osmolyte release is important in preventing water accumulation and swelling. However, the signaling pathways that detect volume increase and activate solute efflux are still not fully understood. We investigated efflux activation of the osmolyte taurine which is actively accumulated in rat thyrocytes (FRTL-5). Efflux of accumulated [(3)H]taurine was stimulated by cellular swelling and thyrotropin (TSH). These effects were significantly diminished in cells having reduced TSH receptor concentrations. Phosphodiesterase inhibitors (IBMX, Rolipram) enhanced both responses. An analog of forskolin (FSK; 7-deacetyl-7-[O-(N-methylpiperazino)-γ-butyryl] dihydrochloride) and an analog of cAMP, specific for activating exchange protein activated directly by cAMP (Epac; 8-(4-chlorophenylthio)-2'-O-methyladenosine-3',5'-cyclic monophosphate, acetoxymethyl ester), significantly stimulated [(3)H]taurine efflux. A cAMP analog specific for activating protein kinase A (PKA; N6-benzoyladenosine-3',5'-cyclic monophosphate, acetoxymethyl ester) had no significant stimulatory effect on [(3)H]taurine efflux rate. The amiloride analog, 5-(N-ethyl-N-isopropyl)-amiloride, which inhibits a TSH-stimulated Na(+)/H(+) exchanger, enhanced (100 %) and ouabain inhibited (50 %) the TSH-stimulated [(3)H]taurine efflux rate. The effect of FSK on efflux was strongly potentiated by Na(+)-free iso-osmotic conditions and by osmolality/cell volume that affected also the db-cAMP-stimulated efflux. The TSH receptors and downstream elements of the signaling pathway comprising adenylyl cyclase, cAMP and Epac appeared to mediate the hormone-induced signal for [(3)H]taurine efflux from FRTL-5 cells. With less evidence, the cell volume/osmolality-induced [(3)H]taurine efflux cascade appeared to share some of the hormone signaling elements and to modulate the hormone signaling pathway at two levels through cellular Na(+).
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Affiliation(s)
- Kjell Fugelli
- Department of Biosciences, University of Oslo, POBox 1066, Blindern, 0316, Oslo, Norway.
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16
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Jo AO, Ryskamp DA, Phuong TTT, Verkman AS, Yarishkin O, MacAulay N, Križaj D. TRPV4 and AQP4 Channels Synergistically Regulate Cell Volume and Calcium Homeostasis in Retinal Müller Glia. J Neurosci 2015; 35:13525-37. [PMID: 26424896 PMCID: PMC4588615 DOI: 10.1523/jneurosci.1987-15.2015] [Citation(s) in RCA: 160] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2015] [Revised: 08/26/2015] [Accepted: 08/27/2015] [Indexed: 11/21/2022] Open
Abstract
Brain edema formation occurs after dysfunctional control of extracellular volume partly through impaired astrocytic ion and water transport. Here, we show that such processes might involve synergistic cooperation between the glial water channel aquaporin 4 (AQP4) and the transient receptor potential isoform 4 (TRPV4), a polymodal swelling-sensitive cation channel. In mouse retinas, TRPV4 colocalized with AQP4 in the end feet and radial processes of Müller astroglia. Genetic ablation of TRPV4 did not affect the distribution of AQP4 and vice versa. However, retinas from Trpv4(-/-) and Aqp4(-/-) mice exhibited suppressed transcription of genes encoding Trpv4, Aqp4, and the Kir4.1 subunit of inwardly rectifying potassium channels. Swelling and [Ca(2+)]i elevations evoked in Müller cells by hypotonic stimulation were antagonized by the selective TRPV4 antagonist HC-067047 (2-methyl-1-[3-(4-morpholinyl)propyl]-5-phenyl-N-[3-(trifluoromethyl)phenyl]-1H-pyrrole-3-carboxamide) or Trpv4 ablation. Elimination of Aqp4 suppressed swelling-induced [Ca(2+)]i elevations but only modestly attenuated the amplitude of Ca(2+) signals evoked by the TRPV4 agonist GSK1016790A [(N-((1S)-1-{[4-((2S)-2-{[(2,4-dichlorophenyl)sulfonyl]amino}-3-hydroxypropanoyl)-1-piperazinyl]carbonyl}-3-methylbutyl)-1-benzothiophene-2-carboxamide]. Glial cells lacking TRPV4 but not AQP4 showed deficits in hypotonic swelling and regulatory volume decrease. Functional synergy between TRPV4 and AQP4 during cell swelling was confirmed in the heterologously expressing Xenopus oocyte model. Importantly, when the swelling rate was osmotically matched for AQP4-positive and AQP4-negative oocytes, TRPV4 activation became independent of AQP4. We conclude that AQP4-mediated water fluxes promote the activation of the swelling sensor, whereas Ca(2+) entry through TRPV4 channels reciprocally modulates volume regulation, swelling, and Aqp4 gene expression. Therefore, TRPV4-AQP4 interactions constitute a molecular system that fine-tunes astroglial volume regulation by integrating osmosensing, calcium signaling, and water transport and, when overactivated, triggers pathological swelling. Significance statement: We characterize the physiological features of interactions between the astroglial swelling sensor transient receptor potential isoform 4 (TRPV4) and the aquaporin 4 (AQP4) water channel in retinal Müller cells. Our data reveal an elegant and complex set of mechanisms involving reciprocal interactions at the level of glial gene expression, calcium homeostasis, swelling, and volume regulation. Specifically, water influx through AQP4 drives calcium influx via TRPV4 in the glial end foot, which regulates expression of Aqp4 and Kir4.1 genes and facilitates the time course and amplitude of hypotonicity-induced swelling and regulatory volume decrease. We confirm the crucial facets of the signaling mechanism in heterologously expressing oocytes. These results identify the molecular mechanism that contributes to dynamic regulation of glial volume but also provide new insights into the pathophysiology of glial reactivity and edema formation.
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Affiliation(s)
- Andrew O Jo
- Department of Ophthalmology and Visual Sciences, Moran Eye Institute
| | - Daniel A Ryskamp
- Department of Ophthalmology and Visual Sciences, Moran Eye Institute, Interdepartmental Program in Neuroscience, and
| | - Tam T T Phuong
- Department of Ophthalmology and Visual Sciences, Moran Eye Institute
| | - Alan S Verkman
- Department of Medicine, University of California San Francisco, San Francisco, California 94143, and
| | - Oleg Yarishkin
- Department of Ophthalmology and Visual Sciences, Moran Eye Institute
| | - Nanna MacAulay
- Department of Cellular and Molecular Medicine, University of Copenhagen, 2200 Copenhagen, Denmark
| | - David Križaj
- Department of Ophthalmology and Visual Sciences, Moran Eye Institute, Interdepartmental Program in Neuroscience, and Department of Neurobiology and Anatomy, University of Utah School of Medicine, Salt Lake City, Utah 84132,
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