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Petersilie L, Heiduschka S, Nelson JS, Neu LA, Le S, Anand R, Kafitz KW, Prigione A, Rose CR. Cortical brain organoid slices (cBOS) for the study of human neural cells in minimal networks. iScience 2024; 27:109415. [PMID: 38523789 PMCID: PMC10957451 DOI: 10.1016/j.isci.2024.109415] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Revised: 01/29/2024] [Accepted: 02/29/2024] [Indexed: 03/26/2024] Open
Abstract
Brain organoids derived from human pluripotent stem cells are a promising tool for studying human neurodevelopment and related disorders. Here, we generated long-term cultures of cortical brain organoid slices (cBOS) grown at the air-liquid interphase from regionalized cortical organoids. We show that cBOS host mature neurons and astrocytes organized in complex architecture. Whole-cell patch-clamp demonstrated subthreshold synaptic inputs and action potential firing of neurons. Spontaneous intracellular calcium signals turned into synchronous large-scale oscillations upon combined disinhibition of NMDA receptors and blocking of GABAA receptors. Brief metabolic inhibition to mimic transient energy restriction in the ischemic brain induced reversible intracellular calcium loading of cBOS. Moreover, metabolic inhibition induced a reversible decline in neuronal ATP as revealed by ATeam1.03YEMK. Overall, cBOS provide a powerful platform to assess morphological and functional aspects of human neural cells in intact minimal networks and to address the pathways that drive cellular damage during brain ischemia.
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Affiliation(s)
- Laura Petersilie
- Institute of Neurobiology, Faculty of Mathematics and Natural Sciences, Heinrich Heine University Duesseldorf, 40225 Duesseldorf, Germany
| | - Sonja Heiduschka
- Department of General Pediatrics, Neonatology and Pediatric Cardiology, University Children’s Hospital and Heinrich Heine University Duesseldorf, 40225 Duesseldorf, Germany
| | - Joel S.E. Nelson
- Institute of Neurobiology, Faculty of Mathematics and Natural Sciences, Heinrich Heine University Duesseldorf, 40225 Duesseldorf, Germany
| | - Louis A. Neu
- Institute of Neurobiology, Faculty of Mathematics and Natural Sciences, Heinrich Heine University Duesseldorf, 40225 Duesseldorf, Germany
| | - Stephanie Le
- Department of General Pediatrics, Neonatology and Pediatric Cardiology, University Children’s Hospital and Heinrich Heine University Duesseldorf, 40225 Duesseldorf, Germany
| | - Ruchika Anand
- Institute of Biochemistry and Molecular Biology I, Medical Faculty and University Hospital Duesseldorf, Heinrich Heine University Duesseldorf, 40225 Duesseldorf, Germany
| | - Karl W. Kafitz
- Institute of Neurobiology, Faculty of Mathematics and Natural Sciences, Heinrich Heine University Duesseldorf, 40225 Duesseldorf, Germany
| | - Alessandro Prigione
- Department of General Pediatrics, Neonatology and Pediatric Cardiology, University Children’s Hospital and Heinrich Heine University Duesseldorf, 40225 Duesseldorf, Germany
| | - Christine R. Rose
- Institute of Neurobiology, Faculty of Mathematics and Natural Sciences, Heinrich Heine University Duesseldorf, 40225 Duesseldorf, Germany
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Theparambil SM, Begum G, Rose CR. pH regulating mechanisms of astrocytes: A critical component in physiology and disease of the brain. Cell Calcium 2024; 120:102882. [PMID: 38631162 DOI: 10.1016/j.ceca.2024.102882] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2024] [Revised: 03/28/2024] [Accepted: 03/28/2024] [Indexed: 04/19/2024]
Abstract
Strict homeostatic control of pH in both intra- and extracellular compartments of the brain is fundamentally important, primarily due to the profound impact of free protons ([H+]) on neuronal activity and overall brain function. Astrocytes, crucial players in the homeostasis of various ions in the brain, actively regulate their intracellular [H+] (pHi) through multiple membrane transporters and carbonic anhydrases. The activation of astroglial pHi regulating mechanisms also leads to corresponding alterations in the acid-base status of the extracellular fluid. Notably, astrocyte pH regulators are modulated by various neuronal signals, suggesting their pivotal role in regulating brain acid-base balance in both health and disease. This review presents the mechanisms involved in pH regulation in astrocytes and discusses their potential impact on extracellular pH under physiological conditions and in brain disorders. Targeting astrocytic pH regulatory mechanisms represents a promising therapeutic approach for modulating brain acid-base balance in diseases, offering a potential critical contribution to neuroprotection.
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Affiliation(s)
- Shefeeq M Theparambil
- Faculty of Health and Medicine, Department of Biomedical and Life Sciences, Lancaster University, Lancaster, LA1 4YW, Lancaster, UK.
| | - Gulnaz Begum
- Department of Neurology, The Pittsburgh Institute for Neurodegenerative Diseases, University of Pittsburgh, Pittsburgh, PA, USA
| | - Christine R Rose
- Institute of Neurobiology, Faculty of Mathematics and Natural Sciences, Heinrich Heine University Düsseldorf, 40225, Düsseldorf, Germany
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Verkhratsky A, Rose CR. Multiple ions control astroglial excitability, or "Nein, Kalzium, ist NICHT alles". Acta Physiol (Oxf) 2024; 240:e14120. [PMID: 38391057 DOI: 10.1111/apha.14120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2024] [Accepted: 02/13/2024] [Indexed: 02/24/2024]
Affiliation(s)
- Alexei Verkhratsky
- Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK
- Achucarro Centre for Neuroscience, IKERBASQUE, Basque Foundation for Science, Bilbao, Spain
- Department of Forensic Analytical Toxicology, School of Forensic Medicine, China Medical University, Shenyang, China
- International Collaborative Centre on Big Science Plan for Purinergic Signalling, Chengdu University of Traditional Chinese Medicine, Chengdu, China
- Department of Stem Cell Biology, State Research Institute Centre for Innovative Medicine, Vilnius, Lithuania
| | - Christine R Rose
- Institute of Neurobiology, Faculty of Mathematics and Natural Sciences, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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Everaerts K, Thapaliya P, Pape N, Durry S, Eitelmann S, Roussa E, Ullah G, Rose CR. Inward Operation of Sodium-Bicarbonate Cotransporter 1 Promotes Astrocytic Na + Loading and Loss of ATP in Mouse Neocortex during Brief Chemical Ischemia. Cells 2023; 12:2675. [PMID: 38067105 PMCID: PMC10705779 DOI: 10.3390/cells12232675] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Revised: 11/14/2023] [Accepted: 11/16/2023] [Indexed: 12/18/2023] Open
Abstract
Ischemic conditions cause an increase in the sodium concentration of astrocytes, driving the breakdown of ionic homeostasis and exacerbating cellular damage. Astrocytes express high levels of the electrogenic sodium-bicarbonate cotransporter1 (NBCe1), which couples intracellular Na+ homeostasis to regulation of pH and operates close to its reversal potential under physiological conditions. Here, we analyzed its mode of operation during transient energy deprivation via imaging astrocytic pH, Na+, and ATP in organotypic slice cultures of the mouse neocortex, complemented with patch-clamp and ion-selective microelectrode recordings and computational modeling. We found that a 2 min period of metabolic failure resulted in a transient acidosis accompanied by a Na+ increase in astrocytes. Inhibition of NBCe1 increased the acidosis while decreasing the Na+ load. Similar results were obtained when comparing ion changes in wild-type and Nbce1-deficient mice. Mathematical modeling replicated these findings and further predicted that NBCe1 activation contributes to the loss of cellular ATP under ischemic conditions, a result confirmed experimentally using FRET-based imaging of ATP. Altogether, our data demonstrate that transient energy failure stimulates the inward operation of NBCe1 in astrocytes. This causes a significant amelioration of ischemia-induced astrocytic acidification, albeit at the expense of increased Na+ influx and a decline in cellular ATP.
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Affiliation(s)
- Katharina Everaerts
- Institute of Neurobiology, Heinrich Heine University Düsseldorf, Universitätsstraße 1, D-40225 Düsseldorf, Germany; (K.E.); (N.P.); (S.D.); (S.E.)
| | - Pawan Thapaliya
- Department of Physics, University of South Florida, Tampa, FL 33620, USA; (P.T.); (G.U.)
| | - Nils Pape
- Institute of Neurobiology, Heinrich Heine University Düsseldorf, Universitätsstraße 1, D-40225 Düsseldorf, Germany; (K.E.); (N.P.); (S.D.); (S.E.)
| | - Simone Durry
- Institute of Neurobiology, Heinrich Heine University Düsseldorf, Universitätsstraße 1, D-40225 Düsseldorf, Germany; (K.E.); (N.P.); (S.D.); (S.E.)
| | - Sara Eitelmann
- Institute of Neurobiology, Heinrich Heine University Düsseldorf, Universitätsstraße 1, D-40225 Düsseldorf, Germany; (K.E.); (N.P.); (S.D.); (S.E.)
| | - Eleni Roussa
- Institute of Anatomy and Cell Biology, Department of Molecular Embryology, Faculty of Medicine, Albert-Ludwigs-Universität Freiburg, Albertstrasse 17, D-79104 Freiburg, Germany;
| | - Ghanim Ullah
- Department of Physics, University of South Florida, Tampa, FL 33620, USA; (P.T.); (G.U.)
| | - Christine R. Rose
- Institute of Neurobiology, Heinrich Heine University Düsseldorf, Universitätsstraße 1, D-40225 Düsseldorf, Germany; (K.E.); (N.P.); (S.D.); (S.E.)
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Stopper G, Caudal LC, Rieder P, Gobbo D, Stopper L, Felix L, Everaerts K, Bai X, Rose CR, Scheller A, Kirchhoff F. Novel algorithms for improved detection and analysis of fluorescent signal fluctuations. Pflugers Arch 2023; 475:1283-1300. [PMID: 37700120 PMCID: PMC10567899 DOI: 10.1007/s00424-023-02855-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Revised: 08/02/2023] [Accepted: 08/26/2023] [Indexed: 09/14/2023]
Abstract
Fluorescent dyes and genetically encoded fluorescence indicators (GEFI) are common tools for visualizing concentration changes of specific ions and messenger molecules during intra- as well as intercellular communication. Using advanced imaging technologies, fluorescence indicators are a prerequisite for the analysis of physiological molecular signaling. Automated detection and analysis of fluorescence signals require to overcome several challenges, including correct estimation of fluorescence fluctuations at basal concentrations of messenger molecules, detection, and extraction of events themselves as well as proper segmentation of neighboring events. Moreover, event detection algorithms need to be sensitive enough to accurately capture localized and low amplitude events exhibiting a limited spatial extent. Here, we present two algorithms (PBasE and CoRoDe) for accurate baseline estimation and automated detection and segmentation of fluorescence fluctuations.
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Affiliation(s)
- Gebhard Stopper
- Department of Molecular Physiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), University of Saarland, Building 48, 66421, Homburg, Germany
| | - Laura C Caudal
- Department of Molecular Physiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), University of Saarland, Building 48, 66421, Homburg, Germany
| | - Phillip Rieder
- Department of Molecular Physiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), University of Saarland, Building 48, 66421, Homburg, Germany
| | - Davide Gobbo
- Department of Molecular Physiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), University of Saarland, Building 48, 66421, Homburg, Germany
| | - Laura Stopper
- Department of Molecular Physiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), University of Saarland, Building 48, 66421, Homburg, Germany
| | - Lisa Felix
- Institute of Neurobiology, Faculty of Mathematics and Natural Sciences, Heinrich Heine University Düsseldorf, 40225, Düsseldorf, Germany
| | - Katharina Everaerts
- Institute of Neurobiology, Faculty of Mathematics and Natural Sciences, Heinrich Heine University Düsseldorf, 40225, Düsseldorf, Germany
| | - Xianshu Bai
- Department of Molecular Physiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), University of Saarland, Building 48, 66421, Homburg, Germany
| | - Christine R Rose
- Institute of Neurobiology, Faculty of Mathematics and Natural Sciences, Heinrich Heine University Düsseldorf, 40225, Düsseldorf, Germany
| | - Anja Scheller
- Department of Molecular Physiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), University of Saarland, Building 48, 66421, Homburg, Germany
| | - Frank Kirchhoff
- Department of Molecular Physiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), University of Saarland, Building 48, 66421, Homburg, Germany.
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Eitelmann S, Everaerts K, Petersilie L, Rose CR, Stephan J. Ca 2+-dependent rapid uncoupling of astrocytes upon brief metabolic stress. Front Cell Neurosci 2023; 17:1151608. [PMID: 37886111 PMCID: PMC10598858 DOI: 10.3389/fncel.2023.1151608] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Accepted: 08/23/2023] [Indexed: 10/28/2023] Open
Abstract
Astrocytic gap junctional coupling is a major element in neuron-glia interaction. There is strong evidence that impaired coupling is involved in neurological disorders. Reduced coupling was, e.g., demonstrated for core regions of ischemic stroke that suffer from massive cell death. In the surrounding penumbra, cells may recover, but recovery is hampered by spreading depolarizations, which impose additional metabolic stress onto the tissue. Spreading depolarizations are characterized by transient breakdown of cellular ion homeostasis, including pH and Ca2+, which might directly affect gap junctional coupling. Here, we exposed acute mouse neocortical tissue slices to brief metabolic stress and examined its effects on the coupling strength between astrocytes. Changes in gap junctional coupling were assessed by recordings of the syncytial isopotentiality. Moreover, quantitative ion imaging was performed in astrocytes to analyze the mechanisms triggering the observed changes. Our experiments show that a 2-minute perfusion of tissue slices with blockers of glycolysis and oxidative phosphorylation causes a rapid uncoupling in half of the recorded cells. They further indicate that uncoupling is not mediated by the accompanying (moderate) intracellular acidification. Dampening large astrocytic Ca2+ loads by removal of extracellular Ca2+ or blocking Ca2+ influx pathways as well as a pharmacological inhibition of calmodulin, however, prevent the uncoupling. Taken together, we conclude that astrocytes exposed to brief episodes of metabolic stress can undergo a rapid, Ca2+/calmodulin-dependent uncoupling. Such uncoupling may help to confine and reduce cellular damage in the ischemic penumbra in vivo.
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Affiliation(s)
| | | | | | - Christine R. Rose
- Institute of Neurobiology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Jonathan Stephan
- Institute of Neurobiology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
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Pape N, Rose CR. Activation of TRPV4 channels promotes the loss of cellular ATP in organotypic slices of the mouse neocortex exposed to chemical ischemia. J Physiol 2023. [PMID: 37195195 DOI: 10.1113/jp284430] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Accepted: 05/15/2023] [Indexed: 05/18/2023] Open
Abstract
The vertebrate brain has an exceptionally high energy need. During ischemia, intracellular ATP concentrations decline rapidly, resulting in the breakdown of ion gradients and cellular damage. Here, we employed the nanosensor ATeam1.03YEMK to analyse the pathways driving the loss of ATP upon transient metabolic inhibition in neurons and astrocytes of the mouse neocortex. We demonstrate that brief chemical ischemia, induced by combined inhibition of glycolysis and oxidative phosphorylation, results in a transient decrease in intracellular ATP. Neurons experienced a larger relative decline and showed less ability to recover from prolonged (>5 minutes) metabolic inhibition than astrocytes. Blocking voltage-gated Na+ channels or NMDA receptors ameliorated the ATP decline in neurons and astrocytes, while blocking glutamate uptake aggravated the overall reduction in neuronal ATP, confirming the central role of excitatory neuronal activity in the cellular energy loss. Unexpectedly, pharmacological inhibition of transient receptor potential vanilloid 4 (TRPV4) channels significantly reduced the ischemia-induced decline in ATP in both cell types. Imaging with Na+ -sensitive indicator dye ING-2 furthermore showed that TRPV4 inhibition also reduced ischemia-induced increases in intracellular Na+ . Altogether, our results demonstrate that neurons exhibit a higher vulnerability to brief metabolic inhibition than astrocytes. Moreover, they reveal an unexpected strong contribution of TRPV4 channels to the loss of cellular ATP and suggest that the demonstrated TRPV4-related ATP consumption is most likely a direct consequence of Na+ influx. Activation of TRPV4 channels thus provides a hitherto unacknowledged contribution to the cellular energy loss during energy failure, generating a significant metabolic cost in ischemic conditions. KEY POINTS: In the ischemic brain, cellular ATP concentrations decline rapidly, which results in the collapse of ion gradients and promotes cellular damage and death. We analysed the pathways driving the loss of ATP upon transient metabolic inhibition in neurons and astrocytes of the mouse neocortex. Our results confirm the central role of excitatory neuronal activity in the cellular energy loss and demonstrate that neurons experience a larger decline in ATP and are more vulnerable to brief metabolic stress than astrocytes. Our study also reveals a new, previously unknown involvement of osmotically-activated transient receptor potential vanilloid 4 (TRPV4) channels to the reduction in cellular ATP in both cell types and indicates that this is a consequence of TRPV4-mediated Na+ influx. We conclude that activation of TRPV4 channels provides a considerable contribution to the cellular energy loss, thereby generating a significant metabolic cost in ischemic conditions. Abstract figure legend We show that brief chemical ischemia, induced by combined inhibition of glycolysis and oxidative phosphorylation results in a transient decrease in cellular ATP of neurons and astrocytes of the murine neocortex. The decline in ATP is promoted by activation of NMDA receptors (NMDA-R), of voltage-gated Na+ channels (Nav) in neurons and of excitatory amino acid transporters (EAATs) in astrocytes. In addition, our study reveals that transient receptor potential vanilloid 4 (TRPV4) channels contribute to the ischemia-induced ATP decline in both cell types. Our data furthermore suggests that the TRPV4-related decline in cellular ATP is caused by TRPV4-related Na+ influx. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Nils Pape
- Institute of Neurobiology, Heinrich Heine University Düsseldorf, Universitätsstraße 1, Düsseldorf, Germany
| | - Christine R Rose
- Institute of Neurobiology, Heinrich Heine University Düsseldorf, Universitätsstraße 1, Düsseldorf, Germany
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Thapaliya P, Pape N, Rose CR, Ullah G. Modeling the heterogeneity of sodium and calcium homeostasis between cortical and hippocampal astrocytes and its impact on bioenergetics. Front Cell Neurosci 2023; 17:1035553. [PMID: 36794264 PMCID: PMC9922870 DOI: 10.3389/fncel.2023.1035553] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Accepted: 01/13/2023] [Indexed: 01/31/2023] Open
Abstract
Emerging evidence indicates that neuronal activity-evoked changes in sodium concentration in astrocytes Na a represent a special form of excitability, which is tightly linked to all other major ions in the astrocyte and extracellular space, as well as to bioenergetics, neurotransmitter uptake, and neurovascular coupling. Recently, one of us reported that Na a transients in the neocortex have a significantly higher amplitude than those in the hippocampus. Based on the extensive data from that study, here we develop a detailed biophysical model to further understand the origin of this heterogeneity and how it affects bioenergetics in the astrocytes. In addition to closely fitting the observed experimental Na a changes under different conditions, our model shows that the heterogeneity in Na a signaling leads to substantial differences in the dynamics of astrocytic Ca2+ signals in the two brain regions, and leaves cortical astrocytes more susceptible to Na+ and Ca2+ overload under metabolic stress. The model also predicts that activity-evoked Na a transients result in significantly larger ATP consumption in cortical astrocytes than in the hippocampus. The difference in ATP consumption is mainly due to the different expression levels of NMDA receptors in the two regions. We confirm predictions from our model experimentally by fluorescence-based measurement of glutamate-induced changes in ATP levels in neocortical and hippocampal astrocytes in the absence and presence of the NMDA receptor's antagonist (2R)-amino-5-phosphonovaleric acid.
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Affiliation(s)
- Pawan Thapaliya
- Department of Physics, University of South Florida, Tampa, FL, United States
| | - Nils Pape
- Faculty of Mathematics and Natural Sciences, Institute of Neurobiology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Christine R. Rose
- Faculty of Mathematics and Natural Sciences, Institute of Neurobiology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Ghanim Ullah
- Department of Physics, University of South Florida, Tampa, FL, United States,*Correspondence: Ghanim Ullah ✉
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Oernbo EK, Steffensen AB, Razzaghi Khamesi P, Toft-Bertelsen TL, Barbuskaite D, Vilhardt F, Gerkau NJ, Tritsaris K, Simonsen AH, Lolansen SD, Andreassen SN, Hasselbalch SG, Zeuthen T, Rose CR, Kurtcuoglu V, MacAulay N. Membrane transporters control cerebrospinal fluid formation independently of conventional osmosis to modulate intracranial pressure. Fluids Barriers CNS 2022; 19:65. [PMID: 36038945 PMCID: PMC9422132 DOI: 10.1186/s12987-022-00358-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Accepted: 07/13/2022] [Indexed: 11/23/2022] Open
Abstract
Background Disturbances in the brain fluid balance can lead to life-threatening elevation in the intracranial pressure (ICP), which represents a vast clinical challenge. Nevertheless, the details underlying the molecular mechanisms governing cerebrospinal fluid (CSF) secretion are largely unresolved, thus preventing targeted and efficient pharmaceutical therapy of cerebral pathologies involving elevated ICP. Methods Experimental rats were employed for in vivo determinations of CSF secretion rates, ICP, blood pressure and ex vivo excised choroid plexus for morphological analysis and quantification of expression and activity of various transport proteins. CSF and blood extractions from rats, pigs, and humans were employed for osmolality determinations and a mathematical model employed to determine a contribution from potential local gradients at the surface of choroid plexus. Results We demonstrate that CSF secretion can occur independently of conventional osmosis and that local osmotic gradients do not suffice to support CSF secretion. Instead, the CSF secretion across the luminal membrane of choroid plexus relies approximately equally on the Na+/K+/2Cl− cotransporter NKCC1, the Na+/HCO3− cotransporter NBCe2, and the Na+/K+-ATPase, but not on the Na+/H+ exchanger NHE1. We demonstrate that pharmacological modulation of CSF secretion directly affects the ICP. Conclusions CSF secretion appears to not rely on conventional osmosis, but rather occur by a concerted effort of different choroidal transporters, possibly via a molecular mode of water transport inherent in the proteins themselves. Therapeutic modulation of the rate of CSF secretion may be employed as a strategy to modulate ICP. These insights identify new promising therapeutic targets against brain pathologies associated with elevated ICP. Supplementary Information The online version contains supplementary material available at 10.1186/s12987-022-00358-4.
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Affiliation(s)
- Eva K Oernbo
- Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3, 2200, Copenhagen, Denmark
| | - Annette B Steffensen
- Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3, 2200, Copenhagen, Denmark
| | - Pooya Razzaghi Khamesi
- Institute of Physiology, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland
| | - Trine L Toft-Bertelsen
- Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3, 2200, Copenhagen, Denmark
| | - Dagne Barbuskaite
- Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3, 2200, Copenhagen, Denmark
| | - Frederik Vilhardt
- Department of Cellular and Molecular Medicine, University of Copenhagen, Blegdamsvej 3, 2200, Copenhagen, Denmark
| | - Niklas J Gerkau
- Institute of Neurobiology, Heinrich Heine University Düsseldorf, Universitätsstrasse 1, 40225, Düsseldorf, Germany
| | - Katerina Tritsaris
- Department of Cellular and Molecular Medicine, University of Copenhagen, Blegdamsvej 3, 2200, Copenhagen, Denmark
| | - Anja H Simonsen
- Danish Dementia Research Centre, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Sara D Lolansen
- Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3, 2200, Copenhagen, Denmark
| | - Søren N Andreassen
- Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3, 2200, Copenhagen, Denmark
| | - Steen G Hasselbalch
- Danish Dementia Research Centre, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Thomas Zeuthen
- Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3, 2200, Copenhagen, Denmark
| | - Christine R Rose
- Institute of Neurobiology, Heinrich Heine University Düsseldorf, Universitätsstrasse 1, 40225, Düsseldorf, Germany
| | - Vartan Kurtcuoglu
- Institute of Physiology, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland
| | - Nanna MacAulay
- Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3, 2200, Copenhagen, Denmark.
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Giannaki M, Ruf DE, Pfeifer E, Everaerts K, Heiland DH, Schnell O, Rose CR, Roussa E. Cell-Type Dependent Regulation of the Electrogenic Na+/HCO3- Cotransporter 1 (NBCe1) by Hypoxia and Acidosis in Glioblastoma. Int J Mol Sci 2022; 23:ijms23168975. [PMID: 36012235 PMCID: PMC9408864 DOI: 10.3390/ijms23168975] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Revised: 08/05/2022] [Accepted: 08/08/2022] [Indexed: 11/16/2022] Open
Abstract
Glioblastoma multiforme (GBM) is the most common and malignant brain tumour. It is characterised by transcriptionally distinct cell populations. In tumour cells, physiological pH gradients between the intracellular and extracellular compartments are reversed, compared to non-cancer cells. Intracellular pH in tumour cells is alkaline, whereas extracellular pH is acidic. Consequently, the function and/or expression of pH regulating transporters might be altered. Here, we investigated protein expression and regulation of the electrogenic sodium/bicarbonate cotransporter 1 (NBCe1) in mesenchymal (MES)-like hypoxia-dependent and -independent cells, as well as in astrocyte-like glioblastoma cells following chemical hypoxia, acidosis and elucidated putative underlying molecular pathways. Immunoblotting, immunocytochemistry, and intracellular pH recording with the H+-sensitive dye 2′,7′-bis-(carboxyethyl)-5-(and-6)-carboxyfluorescein were applied. The results show NBCe1 protein abundance and active NBCe1 transport. Hypoxia upregulated NBCe1 protein and activity in MES-like hypoxia-dependent GBM cells. This effect was positively correlated with HIF-1α protein levels, was mediated by TGF-β signalling, and was prevented by extracellular acidosis. In MES-like hypoxia-independent GBM cells, acidosis (but not hypoxia) regulated NBCe1 activity in an HIF-1α-independent manner. These results demonstrate a cell-specific adaptation of NBCe1 expression and activity to the microenvironment challenge of hypoxia and acidosis that depends on their transcriptional signature in GBM.
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Affiliation(s)
- Marina Giannaki
- Department of Molecular Embryology, Faculty of Medicine, Institute of Anatomy and Cell Biology, Albert-Ludwigs-Universität Freiburg, Albertstrasse 17, D-79104 Freiburg, Germany
| | - Debora E. Ruf
- Department of Molecular Embryology, Faculty of Medicine, Institute of Anatomy and Cell Biology, Albert-Ludwigs-Universität Freiburg, Albertstrasse 17, D-79104 Freiburg, Germany
| | - Emilie Pfeifer
- Department of Molecular Embryology, Faculty of Medicine, Institute of Anatomy and Cell Biology, Albert-Ludwigs-Universität Freiburg, Albertstrasse 17, D-79104 Freiburg, Germany
| | - Katharina Everaerts
- Institute of Neurobiology, Heinrich Heine University, D-40225 Düsseldorf, Germany
| | - Dieter H. Heiland
- Department of Neurosurgery, Faculty of Medicine, Medical Center, University of Freiburg, D-79106 Freiburg, Germany
- Microenvironment and Immunology Research Laboratory, Medical Center, University of Freiburg, D-79106 Freiburg, Germany
| | - Oliver Schnell
- Department of Neurosurgery, Faculty of Medicine, Medical Center, University of Freiburg, D-79106 Freiburg, Germany
| | - Christine R. Rose
- Institute of Neurobiology, Heinrich Heine University, D-40225 Düsseldorf, Germany
| | - Eleni Roussa
- Department of Molecular Embryology, Faculty of Medicine, Institute of Anatomy and Cell Biology, Albert-Ludwigs-Universität Freiburg, Albertstrasse 17, D-79104 Freiburg, Germany
- Correspondence: ; Tel.: +49-761-203-5114
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12
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Barbuskaite D, Oernbo EK, Wardman JH, Toft-Bertelsen TL, Conti E, Andreassen SN, Gerkau NJ, Rose CR, MacAulay N. Acetazolamide modulates intracranial pressure directly by its action on the cerebrospinal fluid secretion apparatus. Fluids Barriers CNS 2022; 19:53. [PMID: 35768824 PMCID: PMC9245291 DOI: 10.1186/s12987-022-00348-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Accepted: 06/01/2022] [Indexed: 01/29/2023] Open
Abstract
Background Elevated intracranial pressure (ICP) is observed in many neurological pathologies, e.g. hydrocephalus and stroke. This condition is routinely relieved with neurosurgical approaches, since effective and targeted pharmacological tools are still lacking. The carbonic anhydrase inhibitor, acetazolamide (AZE), may be employed to treat elevated ICP. However, its effectiveness is questioned, its location of action unresolved, and its tolerability low. Here, we determined the efficacy and mode of action of AZE in the rat . Methods We employed in vivo approaches including ICP and cerebrospinal fluid secretion measurements in anaesthetized rats and telemetric monitoring of ICP and blood pressure in awake rats in combination with ex vivo choroidal radioisotope flux assays and transcriptomic analysis. Results AZE effectively reduced the ICP, irrespective of the mode of drug administration and level of anaesthesia. The effect appeared to occur via a direct action on the choroid plexus and an associated decrease in cerebrospinal fluid secretion, and not indirectly via the systemic action of AZE on renal and vascular processes. Upon a single administration, the reduced ICP endured for approximately 10 h post-AZE delivery with no long-term changes of brain water content or choroidal transporter expression. However, a persistent reduction of ICP was secured with repeated AZE administrations throughout the day. Conclusions AZE lowers ICP directly via its ability to reduce the choroid plexus CSF secretion, irrespective of mode of drug administration. Supplementary Information The online version contains supplementary material available at 10.1186/s12987-022-00348-6.
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Affiliation(s)
- Dagne Barbuskaite
- Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3, 2200, Copenhagen, Denmark
| | - Eva K Oernbo
- Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3, 2200, Copenhagen, Denmark
| | - Jonathan H Wardman
- Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3, 2200, Copenhagen, Denmark
| | - Trine L Toft-Bertelsen
- Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3, 2200, Copenhagen, Denmark
| | - Eller Conti
- Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3, 2200, Copenhagen, Denmark
| | - Søren N Andreassen
- Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3, 2200, Copenhagen, Denmark
| | - Niklas J Gerkau
- Institute of Neurobiology, Heinrich Heine University, Universitätsstrasse 1, 40225, Düsseldorf, Germany
| | - Christine R Rose
- Institute of Neurobiology, Heinrich Heine University, Universitätsstrasse 1, 40225, Düsseldorf, Germany
| | - Nanna MacAulay
- Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3, 2200, Copenhagen, Denmark.
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13
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Eitelmann S, Stephan J, Everaerts K, Durry S, Pape N, Gerkau NJ, Rose CR. Changes in Astroglial K + upon Brief Periods of Energy Deprivation in the Mouse Neocortex. Int J Mol Sci 2022; 23:ijms23094836. [PMID: 35563238 PMCID: PMC9102782 DOI: 10.3390/ijms23094836] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Revised: 04/21/2022] [Accepted: 04/24/2022] [Indexed: 11/16/2022] Open
Abstract
Malfunction of astrocytic K+ regulation contributes to the breakdown of extracellular K+ homeostasis during ischemia and spreading depolarization events. Studying astroglial K+ changes is, however, hampered by a lack of suitable techniques. Here, we combined results from fluorescence imaging, ion-selective microelectrodes, and patch-clamp recordings in murine neocortical slices with the calculation of astrocytic [K+]. Brief chemical ischemia caused a reversible ATP reduction and a transient depolarization of astrocytes. Moreover, astrocytic [Na+] increased by 24 mM and extracellular [Na+] decreased. Extracellular [K+] increased, followed by an undershoot during recovery. Feeding these data into the Goldman-Hodgkin-Katz equation revealed a baseline astroglial [K+] of 146 mM, an initial K+ loss by 43 mM upon chemical ischemia, and a transient K+ overshoot of 16 mM during recovery. It also disclosed a biphasic mismatch in astrocytic Na+/K+ balance, which was initially ameliorated, but later aggravated by accompanying changes in pH and bicarbonate, respectively. Altogether, our study predicts a loss of K+ from astrocytes upon chemical ischemia followed by a net gain. The overshooting K+ uptake will promote low extracellular K+ during recovery, likely exerting a neuroprotective effect. The resulting late cation/anion imbalance requires additional efflux of cations and/or influx of anions, the latter eventually driving delayed astrocyte swelling.
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14
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Engels M, Kalia M, Rahmati S, Petersilie L, Kovermann P, van Putten MJAM, Rose CR, Meijer HGE, Gensch T, Fahlke C. Glial Chloride Homeostasis Under Transient Ischemic Stress. Front Cell Neurosci 2021; 15:735300. [PMID: 34602981 PMCID: PMC8481871 DOI: 10.3389/fncel.2021.735300] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Accepted: 08/23/2021] [Indexed: 12/17/2022] Open
Abstract
High water permeabilities permit rapid adjustments of glial volume upon changes in external and internal osmolarity, and pathologically altered intracellular chloride concentrations ([Cl–]int) and glial cell swelling are often assumed to represent early events in ischemia, infections, or traumatic brain injury. Experimental data for glial [Cl–]int are lacking for most brain regions, under normal as well as under pathological conditions. We measured [Cl–]int in hippocampal and neocortical astrocytes and in hippocampal radial glia-like (RGL) cells in acute murine brain slices using fluorescence lifetime imaging microscopy with the chloride-sensitive dye MQAE at room temperature. We observed substantial heterogeneity in baseline [Cl–]int, ranging from 14.0 ± 2.0 mM in neocortical astrocytes to 28.4 ± 3.0 mM in dentate gyrus astrocytes. Chloride accumulation by the Na+-K+-2Cl– cotransporter (NKCC1) and chloride outward transport (efflux) through K+-Cl– cotransporters (KCC1 and KCC3) or excitatory amino acid transporter (EAAT) anion channels control [Cl–]int to variable extent in distinct brain regions. In hippocampal astrocytes, blocking NKCC1 decreased [Cl–]int, whereas KCC or EAAT anion channel inhibition had little effect. In contrast, neocortical astrocytic or RGL [Cl–]int was very sensitive to block of chloride outward transport, but not to NKCC1 inhibition. Mathematical modeling demonstrated that higher numbers of NKCC1 and KCC transporters can account for lower [Cl–]int in neocortical than in hippocampal astrocytes. Energy depletion mimicking ischemia for up to 10 min did not result in pronounced changes in [Cl–]int in any of the tested glial cell types. However, [Cl–]int changes occurred under ischemic conditions after blocking selected anion transporters. We conclude that stimulated chloride accumulation and chloride efflux compensate for each other and prevent glial swelling under transient energy deprivation.
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Affiliation(s)
- Miriam Engels
- Institute of Biological Information Processing, Molekular-und Zellphysiologie (IBI-1), Forschungszentrum Jülich, Jülich, Germany
| | - Manu Kalia
- Applied Analysis, Department of Applied Mathematics, University of Twente, Enschede, Netherlands.,Institute of Neurobiology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Sarah Rahmati
- Institute of Biological Information Processing, Molekular-und Zellphysiologie (IBI-1), Forschungszentrum Jülich, Jülich, Germany
| | - Laura Petersilie
- Institute of Neurobiology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Peter Kovermann
- Institute of Biological Information Processing, Molekular-und Zellphysiologie (IBI-1), Forschungszentrum Jülich, Jülich, Germany
| | | | - Christine R Rose
- Institute of Neurobiology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Hil G E Meijer
- Applied Analysis, Department of Applied Mathematics, University of Twente, Enschede, Netherlands
| | - Thomas Gensch
- Institute of Biological Information Processing, Molekular-und Zellphysiologie (IBI-1), Forschungszentrum Jülich, Jülich, Germany
| | - Christoph Fahlke
- Institute of Biological Information Processing, Molekular-und Zellphysiologie (IBI-1), Forschungszentrum Jülich, Jülich, Germany
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15
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Kapr J, Petersilie L, Distler T, Lauria I, Bendt F, Sauter CM, Boccaccini AR, Rose CR, Fritsche E. Human Induced Pluripotent Stem Cell-Derived Neural Progenitor Cells Produce Distinct Neural 3D In Vitro Models Depending on Alginate/Gellan Gum/Laminin Hydrogel Blend Properties. Adv Healthc Mater 2021; 10:e2100131. [PMID: 34197049 DOI: 10.1002/adhm.202100131] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Revised: 06/01/2021] [Indexed: 12/12/2022]
Abstract
Stable and predictive neural cell culture models are a necessary premise for many research fields. However, conventional 2D models lack 3D cell-material/-cell interactions and hence do not reflect the complexity of the in vivo situation properly. Here two alginate/gellan gum/laminin (ALG/GG/LAM) hydrogel blends are presented for the fabrication of human induced pluripotent stem cell (hiPSC)-based 3D neural models. For hydrogel embedding, hiPSC-derived neural progenitor cells (hiNPCs) are used either directly or after 3D neural pre-differentiation. It is shown that stiffness and stress relaxation of the gel blends, as well as the cell differentiation strategy influence 3D model development. The embedded hiNPCs differentiate into neurons and astrocytes within the gel blends and display spontaneous intracellular calcium signals. Two fit-for-purpose models valuable for i) applications requiring a high degree of complexity, but less throughput, such as disease modeling and long-term exposure studies and ii) higher throughput applications, such as acute exposures or substance screenings are proposed. Due to their wide range of applications, adjustability, and printing capabilities, the ALG/GG/LAM based 3D neural models are of great potential for 3D neural modeling in the future.
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Affiliation(s)
- Julia Kapr
- IUF – Leibniz Research Institute for Environmental Medicine Düsseldorf 40225 Germany
| | - Laura Petersilie
- Institute of Neurobiology Heinrich Heine University Düsseldorf 40225 Germany
| | - Thomas Distler
- Institute of Biomaterials Department of Materials Science and Engineering Friedrich‐Alexander‐University Erlangen‐Nuremberg Erlangen 91054 Germany
| | - Ines Lauria
- IUF – Leibniz Research Institute for Environmental Medicine Düsseldorf 40225 Germany
| | - Farina Bendt
- IUF – Leibniz Research Institute for Environmental Medicine Düsseldorf 40225 Germany
| | - Clemens M. Sauter
- IUF – Leibniz Research Institute for Environmental Medicine Düsseldorf 40225 Germany
| | - Aldo R. Boccaccini
- Institute of Biomaterials Department of Materials Science and Engineering Friedrich‐Alexander‐University Erlangen‐Nuremberg Erlangen 91054 Germany
| | - Christine R. Rose
- Institute of Neurobiology Heinrich Heine University Düsseldorf 40225 Germany
| | - Ellen Fritsche
- IUF – Leibniz Research Institute for Environmental Medicine Düsseldorf 40225 Germany
- Medical Faculty Heinrich Heine University Düsseldorf 40225 Germany
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16
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Le S, Petersilie L, Inak G, Menacho-Pando C, Kafitz KW, Rybak-Wolf A, Rajewsky N, Rose CR, Prigione A. Generation of Human Brain Organoids for Mitochondrial Disease Modeling. J Vis Exp 2021. [PMID: 34223837 DOI: 10.3791/62756] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Mitochondrial diseases represent the largest class of inborn errors of metabolism and are currently incurable. These diseases cause neurodevelopmental defects whose underlying mechanisms remain to be elucidated. A major roadblock is the lack of effective models recapitulating the early-onset neuronal impairment seen in the patients. Advances in the technology of induced pluripotent stem cells (iPSCs) enable the generation of three-dimensional (3D) brain organoids that can be used to investigate the impact of diseases on the development and organization of the nervous system. Researchers, including these authors, have recently introduced human brain organoids to model mitochondrial disorders. This paper reports a detailed protocol for the robust generation of human iPSC-derived brain organoids and their use in mitochondrial bioenergetic profiling and imaging analyses. These experiments will allow the use of brain organoids to investigate metabolic and developmental dysfunctions and may provide crucial information to dissect the neuronal pathology of mitochondrial diseases.
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Affiliation(s)
- Stephanie Le
- Department of General Pediatrics, Neonatology and Pediatric Cardiology, Duesseldorf University Hospital, Medical Faculty, Heinrich Heine University
| | | | - Gizem Inak
- Department of General Pediatrics, Neonatology and Pediatric Cardiology, Duesseldorf University Hospital, Medical Faculty, Heinrich Heine University; Seaver Autism Center for Research and Treatment, Icahn School of Medicine at Mount Sinai
| | - Carmen Menacho-Pando
- Department of General Pediatrics, Neonatology and Pediatric Cardiology, Duesseldorf University Hospital, Medical Faculty, Heinrich Heine University
| | - Karl W Kafitz
- Institute of Neurobiology, Heinrich Heine University
| | - Agnieszka Rybak-Wolf
- Berlin Institute for Medical Systems Biology (BIMSB), Max Delbrueck Center for Molecular Medicine (MDC)
| | - Nikolaus Rajewsky
- Berlin Institute for Medical Systems Biology (BIMSB), Max Delbrueck Center for Molecular Medicine (MDC)
| | | | - Alessandro Prigione
- Department of General Pediatrics, Neonatology and Pediatric Cardiology, Duesseldorf University Hospital, Medical Faculty, Heinrich Heine University; Max Delbrueck Center for Molecular Medicine (MDC);
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17
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Kalia M, Meijer HGE, van Gils SA, van Putten MJAM, Rose CR. Ion dynamics at the energy-deprived tripartite synapse. PLoS Comput Biol 2021; 17:e1009019. [PMID: 34143772 PMCID: PMC8244923 DOI: 10.1371/journal.pcbi.1009019] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Revised: 06/30/2021] [Accepted: 04/28/2021] [Indexed: 01/09/2023] Open
Abstract
The anatomical and functional organization of neurons and astrocytes at 'tripartite synapses' is essential for reliable neurotransmission, which critically depends on ATP. In low energy conditions, synaptic transmission fails, accompanied by a breakdown of ion gradients, changes in membrane potentials and cell swelling. The resulting cellular damage and cell death are causal to the often devastating consequences of an ischemic stroke. The severity of ischemic damage depends on the age and the brain region in which a stroke occurs, but the reasons for this differential vulnerability are far from understood. In the present study, we address this question by developing a comprehensive biophysical model of a glutamatergic synapse to identify key determinants of synaptic failure during energy deprivation. Our model is based on fundamental biophysical principles, includes dynamics of the most relevant ions, i.e., Na+, K+, Ca2+, Cl- and glutamate, and is calibrated with experimental data. It confirms the critical role of the Na+/K+-ATPase in maintaining ion gradients, membrane potentials and cell volumes. Our simulations demonstrate that the system exhibits two stable states, one physiological and one pathological. During energy deprivation, the physiological state may disappear, forcing a transit to the pathological state, which can be reverted when blocking voltage-gated Na+ and K+ channels. Our model predicts that the transition to the pathological state is favoured if the extracellular space fraction is small. A reduction in the extracellular space volume fraction, as, e.g. observed with ageing, will thus promote the brain's susceptibility to ischemic damage. Our work provides new insights into the brain's ability to recover from energy deprivation, with translational relevance for diagnosis and treatment of ischemic strokes.
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Affiliation(s)
- Manu Kalia
- Applied Analysis, Department of Applied Mathematics, University of Twente, Enschede, The Netherlands
- * E-mail:
| | - Hil G. E. Meijer
- Applied Analysis, Department of Applied Mathematics, University of Twente, Enschede, The Netherlands
| | - Stephan A. van Gils
- Applied Analysis, Department of Applied Mathematics, University of Twente, Enschede, The Netherlands
| | | | - Christine R. Rose
- Institute of Neurobiology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
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18
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van Putten MJ, Fahlke C, Kafitz KW, Hofmeijer J, Rose CR. Dysregulation of Astrocyte Ion Homeostasis and Its Relevance for Stroke-Induced Brain Damage. Int J Mol Sci 2021; 22:5679. [PMID: 34073593 PMCID: PMC8198632 DOI: 10.3390/ijms22115679] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Revised: 05/21/2021] [Accepted: 05/22/2021] [Indexed: 12/14/2022] Open
Abstract
Ischemic stroke is a leading cause of mortality and chronic disability. Either recovery or progression towards irreversible failure of neurons and astrocytes occurs within minutes to days, depending on remaining perfusion levels. Initial damage arises from energy depletion resulting in a failure to maintain homeostasis and ion gradients between extra- and intracellular spaces. Astrocytes play a key role in these processes and are thus central players in the dynamics towards recovery or progression of stroke-induced brain damage. Here, we present a synopsis of the pivotal functions of astrocytes at the tripartite synapse, which form the basis of physiological brain functioning. We summarize the evidence of astrocytic failure and its consequences under ischemic conditions. Special emphasis is put on the homeostasis and stroke-induced dysregulation of the major monovalent ions, namely Na+, K+, H+, and Cl-, and their involvement in maintenance of cellular volume and generation of cerebral edema.
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Affiliation(s)
- Michel J.A.M. van Putten
- Department of Clinical Neurophysiology, University of Twente, 7522 NB Enschede, The Netherlands; (M.J.A.M.v.P.); (J.H.)
| | - Christoph Fahlke
- Institut für Biologische Informationsprozesse, Molekular-und Zellphysiologie (IBI-1), Forschungszentrum Jülich, 52425 Jülich, Germany;
| | - Karl W. Kafitz
- Institute of Neurobiology, Heinrich Heine University Düsseldorf, 40225 Düsseldorf, Germany;
| | - Jeannette Hofmeijer
- Department of Clinical Neurophysiology, University of Twente, 7522 NB Enschede, The Netherlands; (M.J.A.M.v.P.); (J.H.)
| | - Christine R. Rose
- Institute of Neurobiology, Heinrich Heine University Düsseldorf, 40225 Düsseldorf, Germany;
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19
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Escartin C, Galea E, Lakatos A, O'Callaghan JP, Petzold GC, Serrano-Pozo A, Steinhäuser C, Volterra A, Carmignoto G, Agarwal A, Allen NJ, Araque A, Barbeito L, Barzilai A, Bergles DE, Bonvento G, Butt AM, Chen WT, Cohen-Salmon M, Cunningham C, Deneen B, De Strooper B, Díaz-Castro B, Farina C, Freeman M, Gallo V, Goldman JE, Goldman SA, Götz M, Gutiérrez A, Haydon PG, Heiland DH, Hol EM, Holt MG, Iino M, Kastanenka KV, Kettenmann H, Khakh BS, Koizumi S, Lee CJ, Liddelow SA, MacVicar BA, Magistretti P, Messing A, Mishra A, Molofsky AV, Murai KK, Norris CM, Okada S, Oliet SHR, Oliveira JF, Panatier A, Parpura V, Pekna M, Pekny M, Pellerin L, Perea G, Pérez-Nievas BG, Pfrieger FW, Poskanzer KE, Quintana FJ, Ransohoff RM, Riquelme-Perez M, Robel S, Rose CR, Rothstein JD, Rouach N, Rowitch DH, Semyanov A, Sirko S, Sontheimer H, Swanson RA, Vitorica J, Wanner IB, Wood LB, Wu J, Zheng B, Zimmer ER, Zorec R, Sofroniew MV, Verkhratsky A. Reactive astrocyte nomenclature, definitions, and future directions. Nat Neurosci 2021; 24:312-325. [PMID: 33589835 PMCID: PMC8007081 DOI: 10.1038/s41593-020-00783-4] [Citation(s) in RCA: 937] [Impact Index Per Article: 312.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Accepted: 12/16/2020] [Indexed: 12/18/2022]
Abstract
Reactive astrocytes are astrocytes undergoing morphological, molecular, and functional remodeling in response to injury, disease, or infection of the CNS. Although this remodeling was first described over a century ago, uncertainties and controversies remain regarding the contribution of reactive astrocytes to CNS diseases, repair, and aging. It is also unclear whether fixed categories of reactive astrocytes exist and, if so, how to identify them. We point out the shortcomings of binary divisions of reactive astrocytes into good-vs-bad, neurotoxic-vs-neuroprotective or A1-vs-A2. We advocate, instead, that research on reactive astrocytes include assessment of multiple molecular and functional parameters-preferably in vivo-plus multivariate statistics and determination of impact on pathological hallmarks in relevant models. These guidelines may spur the discovery of astrocyte-based biomarkers as well as astrocyte-targeting therapies that abrogate detrimental actions of reactive astrocytes, potentiate their neuro- and glioprotective actions, and restore or augment their homeostatic, modulatory, and defensive functions.
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Affiliation(s)
- Carole Escartin
- Université Paris-Saclay, CEA, CNRS, MIRCen, Laboratoire des Maladies Neurodégénératives, Fontenay-aux-Roses, France.
| | - Elena Galea
- Institut de Neurociències and Departament de Bioquímica i Biologia Molecular, Unitat de Bioquímica de Medicina, Universitat Autònoma de Barcelona, Barcelona, Spain.
- ICREA, Barcelona, Spain.
| | - András Lakatos
- John van Geest Centre for Brain Repair and Division of Stem Cell Neurobiology, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
- Wellcome Trust-MRC Cambridge Stem Cell Institute, Cambridge Biomedical Campus, Cambridge, UK
| | - James P O'Callaghan
- Health Effects Laboratory Division, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, Morgantown, West Virginia, USA
| | - Gabor C Petzold
- German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany
- Division of Vascular Neurology, Department of Neurology, University Hospital Bonn, Bonn, Germany
| | - Alberto Serrano-Pozo
- Alzheimer Research Unit, Department of Neurology, Massachusetts General Hospital, Charlestown, Massachusetts, USA
- Harvard Medical School, Boston, Massachusetts, USA
| | - Christian Steinhäuser
- Institute of Cellular Neurosciences, Medical Faculty, University of Bonn, Bonn, Germany
| | - Andrea Volterra
- Department of Fundamental Neuroscience, University of Lausanne, Lausanne, Switzerland
| | - Giorgio Carmignoto
- Neuroscience Institute, Italian National Research Council (CNR), Padua, Italy
- Department of Biomedical Sciences, University of Padua, Padua, Italy
| | - Amit Agarwal
- The Chica and Heinz Schaller Research Group, Institute for Anatomy and Cell Biology, Heidelberg University, Heidelberg, Germany
| | - Nicola J Allen
- Salk Institute for Biological Studies, Molecular Neurobiology Laboratory, La Jolla, California, USA
| | - Alfonso Araque
- Department of Neuroscience, University of Minnesota, Minneapolis, Minnesota, USA
| | | | - Ari Barzilai
- Department of Neurobiology, George S. Wise, Faculty of Life Sciences and Sagol School of Neuroscience, Tel Aviv University, Ramat Aviv Tel Aviv, Israel
| | - Dwight E Bergles
- The Solomon H. Snyder Department of Neuroscience, Kavli Neuroscience Discovery Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Gilles Bonvento
- Université Paris-Saclay, CEA, CNRS, MIRCen, Laboratoire des Maladies Neurodégénératives, Fontenay-aux-Roses, France
| | - Arthur M Butt
- School of Pharmacy and Biomedical Science, University of Portsmouth, Portsmouth, UK
| | - Wei-Ting Chen
- Center for Brain and Disease Research, VIB and University of Leuven, Leuven, Belgium
| | - Martine Cohen-Salmon
- 'Physiology and Physiopathology of the Gliovascular Unit' Research Group, Center for Interdisciplinary Research in Biology (CIRB), College de France, Unité Mixte de Recherche 7241 CNRS, Unité1050 INSERM, PSL Research University, Paris, France
| | - Colm Cunningham
- Trinity Biomedical Sciences Institute & Trinity College Institute of Neuroscience, School of Biochemistry & Immunology, Trinity College Dublin, Dublin, Republic of Ireland
| | - Benjamin Deneen
- Center for Cell and Gene Therapy, Department of Neurosurgery, Baylor College of Medicine, Houston, Texas, USA
| | - Bart De Strooper
- Center for Brain and Disease Research, VIB and University of Leuven, Leuven, Belgium
- UK Dementia Research Institute at the University College London, London, UK
| | - Blanca Díaz-Castro
- UK Dementia Research Institute at the University of Edinburgh, Centre for Discovery Brain Sciences, Edinburgh, UK
| | - Cinthia Farina
- Institute of Experimental Neurology (INSpe) and Division of Neuroscience, San Raffaele Scientific Institute, Milan, Italy
| | | | - Vittorio Gallo
- Center for Neuroscience Research, Children's National Research Institute, Children's National Hospital, Washington DC, USA
| | - James E Goldman
- Department of Pathology & Cell Biology, Columbia University, New York, New York, USA
| | - Steven A Goldman
- University of Rochester Medical Center, Rochester, New York, USA
- Center for Translational Neuromedicine, University of Copenhagen Faculty of Health and Medical Science and Rigshospitalet, Kobenhavn N, Denmark
| | - Magdalena Götz
- Physiological Genomics, Biomedical Center, Ludwig-Maximilians-Universitaet & Institute of Stem Cell Research, Helmholtz Center Munich, Munich, Germany
- Synergy, Excellence Cluster of Systems Neurology, Biomedical Center, Munich, Germany
| | - Antonia Gutiérrez
- Dpto. Biología Celular, Genética y Fisiología, Instituto de Investigación Biomédica de Málaga-IBIMA, Facultad de Ciencias, Universidad de Málaga, Málaga, Spain
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
| | - Philip G Haydon
- Department of Neuroscience, Tufts University School of Medicine, Boston, Massachusetts, USA
| | - Dieter H Heiland
- Microenvironment and Immunology Research Laboratory, Medical Center, Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Department of Neurosurgery, Medical Center, University of Freiburg, Faculty of Medicine, Freiburg, Germany
| | - Elly M Hol
- Department of Translational Neuroscience, University Medical Center Utrecht Brain Center, Utrecht University, Utrecht, The Netherlands
| | - Matthew G Holt
- Laboratory of Glia Biology, VIB-KU Leuven Center for Brain and Disease Research, Leuven, Belgium
| | - Masamitsu Iino
- Division of Cellular and Molecular Pharmacology, Nihon University School of Medicine, Tokyo, Japan
| | - Ksenia V Kastanenka
- Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts, USA
| | - Helmut Kettenmann
- Cellular Neurosciences, Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
| | - Baljit S Khakh
- Department of Physiology, David Geffen School of Medicine at UCLA, Los Angeles, California, USA
| | - Schuichi Koizumi
- Department of Neuropharmacology, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Yamanashi, Japan
| | - C Justin Lee
- Center for Cognition and Sociality, Institute for Basic Science 55, Expo-ro, Yuseong-gu, Daejeon, Korea
| | - Shane A Liddelow
- Neuroscience Institute, Department of Neuroscience and Physiology, Department of Ophthalmology, NYU School of Medicine, New York, USA
| | - Brian A MacVicar
- Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, British Columbia, Canada
| | - Pierre Magistretti
- Division of Biological and Environmental Sciences and Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
- Centre de Neurosciences Psychiatriques, University of Lausanne and CHUV, Site de Cery, Prilly-Lausanne, Lausanne, Switzerland
| | - Albee Messing
- Waisman Center and School of Veterinary Medicine, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Anusha Mishra
- Department of Neurology Jungers Center for Neurosciences Research and Knight Cardiovascular Institute, Oregon Health & Science University, Portland, Oregon, USA
| | - Anna V Molofsky
- Departments of Psychiatry/Weill Institute for Neuroscience University of California, San Francisco, California, USA
| | - Keith K Murai
- Centre for Research in Neuroscience, Department of Neurology & Neurosurgery, Brain Repair and Integrative Neuroscience Program, Research Institute of the McGill University Health Centre, Montreal, Quebec, Canada
| | - Christopher M Norris
- Sanders-Brown Center on Aging, University of Kentucky College of Medicine, Lexington, Kentucky, USA
| | - Seiji Okada
- Department of Immunobiology and Neuroscience, Medical Institute of Bioregulation, Kyushu University, Fukuoka, Japan
| | - Stéphane H R Oliet
- Université de Bordeaux, Inserm, Neurocentre Magendie, U1215, Bordeaux, France
| | - João F Oliveira
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal
- ICVS/3B's -PT Government Associate Laboratory, Braga/Guimarães, Portugal
- IPCA-EST-2Ai, Polytechnic Institute of Cávado and Ave, Applied Artificial Intelligence Laboratory, Campus of IPCA, Barcelos, Portugal
| | - Aude Panatier
- Université de Bordeaux, Inserm, Neurocentre Magendie, U1215, Bordeaux, France
| | - Vladimir Parpura
- Department of Neurobiology, The University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Marcela Pekna
- Laboratory of Regenerative Neuroimmunology, Center for Brain Repair, Department of Clinical Neuroscience, Institute of Neuroscience and Physiology, Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden
| | - Milos Pekny
- Laboratory of Astrocyte Biology and CNS Regeneration, Center for Brain Repair, Department of Clinical Neuroscience, Institute of Neuroscience and Physiology, Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden
| | - Luc Pellerin
- INSERM U1082, Université de Poitiers, Poitiers, France
| | - Gertrudis Perea
- Department of Functional and Systems Neurobiology, Cajal Institute, CSIC, Madrid, Spain
| | - Beatriz G Pérez-Nievas
- Department of Basic and Clinical Neuroscience, Maurice Wohl Clinical Neuroscience Institute, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
| | - Frank W Pfrieger
- Centre National de la Recherche Scientifique, Université de Strasbourg, Institut des Neurosciences Cellulaires et Intégratives, Strasbourg, France
| | - Kira E Poskanzer
- Department of Biochemistry & Biophysics, Kavli Institute for Fundamental Neuroscience, University of California, San Francisco, California, USA
| | - Francisco J Quintana
- Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital, Harvard Medical School. Associate Member, The Broad Institute, Boston, Massachusetts, USA
| | | | - Miriam Riquelme-Perez
- Université Paris-Saclay, CEA, CNRS, MIRCen, Laboratoire des Maladies Neurodégénératives, Fontenay-aux-Roses, France
| | - Stefanie Robel
- Fralin Biomedical Research Institute at Virginia Tech Carilion, School of Neuroscience Virginia Tech, Riverside Circle, Roanoke, Virginia, USA
| | - Christine R Rose
- Institute of Neurobiology, Heinrich Heine University, Düsseldorf, Germany
| | - Jeffrey D Rothstein
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Nathalie Rouach
- Neuroglial Interactions in Cerebral Physiology and Pathologies, Center for Interdisciplinary Research in Biology, Collège de France, CNRS UMR 7241, INSERM U1050, Labex Memolife, PSL Research University Paris, Paris, France
| | - David H Rowitch
- Wellcome Trust-MRC Cambridge Stem Cell Institute, Cambridge Biomedical Campus, Cambridge, UK
| | - Alexey Semyanov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Moscow, Russia
- Sechenov First Moscow State Medical University, Moscow, Russia
| | - Swetlana Sirko
- Physiological Genomics, Biomedical Center, LMU Munich, Munich, Germany
- Institute for Stem Cell Research, Helmholtz Zentrum Munich, Neuherberg, Germany
| | - Harald Sontheimer
- Virginia Tech School of Neuroscience and Center for Glial Biology in Health, Disease and Cancer, Virginia Tech at the Fralin Biomedical Research Institute, Roanoke, Virginia, USA
| | - Raymond A Swanson
- Dept. of Neurology, University of California San Francisco and San Francisco Veterans Affairs Health Care System, San Francisco, California, USA
| | - Javier Vitorica
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
- Dept. Bioquímica y Biología Molecular, Instituto de Biomedicina de Sevilla, Universidad de Sevilla, Hospital Virgen del Rocío/CSIC, Sevilla, Spain
| | - Ina-Beate Wanner
- Semel Institute for Neuroscience & Human Behavior, IDDRC, David Geffen School of Medicine, UCLA, Los Angeles, California, USA
| | - Levi B Wood
- George W. Woodruff School of Mechanical Engineering, Wallace H. Coulter Department of Biomedical Engineering at Georgia Tech and Emory, and Parker H. Petit Institute for Bioengineering & Bioscience, Georgia Institute of Technology, Atlanta, Georgia, USA
| | - Jiaqian Wu
- The Vivian L. Smith Department of Neurosurgery, Center for Stem Cell and Regenerative Medicine, MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, McGovern Medical School, UTHealth, University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Binhai Zheng
- Department of Neurosciences, UC San Diego School of Medicine, La Jolla; VA San Diego Research Service, San Diego, CA, USA
| | - Eduardo R Zimmer
- Department of Pharmacology, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Robert Zorec
- Laboratory of Neuroendocrinology, Molecular Cell Physiology, Institute of Pathophysiology, University of Ljubljana, Faculty of Medicine, Ljubljana, Slovenia
- Celica Biomedical, 1000, Ljubljana, Slovenia
| | - Michael V Sofroniew
- Department of Neurobiology, David Geffen School of Medicine, University of California, Los Angeles, California, USA.
| | - Alexei Verkhratsky
- Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK.
- Achúcarro Basque Center for Neuroscience, IKERBASQUE, Basque Foundation for Science, Bilbao, Spain.
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20
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Deutsch M, Günther A, Lerchundi R, Rose CR, Balfanz S, Baumann A. AAV-Mediated CRISPRi and RNAi Based Gene Silencing in Mouse Hippocampal Neurons. Cells 2021; 10:324. [PMID: 33557342 PMCID: PMC7915209 DOI: 10.3390/cells10020324] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Revised: 01/27/2021] [Accepted: 01/30/2021] [Indexed: 12/12/2022] Open
Abstract
Uncovering the physiological role of individual proteins that are part of the intricate process of cellular signaling is often a complex and challenging task. A straightforward strategy of studying a protein's function is by manipulating the expression rate of its gene. In recent years, the Clustered Regularly Interspaced Short Palindromic Repeat (CRISPR)/Cas9-based technology was established as a powerful gene-editing tool for generating sequence specific changes in proliferating cells. However, obtaining homogeneous populations of transgenic post-mitotic neurons by CRISPR/Cas9 turned out to be challenging. These constraints can be partially overcome by CRISPR interference (CRISPRi), which mediates the inhibition of gene expression by competing with the transcription machinery for promoter binding and, thus, transcription initiation. Notably, CRISPR/Cas is only one of several described approaches for the manipulation of gene expression. Here, we targeted neurons with recombinant Adeno-associated viruses to induce either CRISPRi or RNA interference (RNAi), a well-established method for impairing de novo protein biosynthesis by using cellular regulatory mechanisms that induce the degradation of pre-existing mRNA. We specifically targeted hyperpolarization-activated and cyclic nucleotide-gated (HCN) channels, which are widely expressed in neuronal tissues and play essential physiological roles in maintaining biophysical characteristics in neurons. Both of the strategies reduced the expression levels of three HCN isoforms (HCN1, 2, and 4) with high specificity. Furthermore, detailed analysis revealed that the knock-down of just a single HCN isoform (HCN4) in hippocampal neurons did not affect basic electrical parameters of transduced neurons, whereas substantial changes emerged in HCN-current specific properties.
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Affiliation(s)
- Matthias Deutsch
- Forschungszentrum Jülich, Institute of Biological Information Processing, IBI-1, Leo-Brandt-Straße, 52428 Jülich, Germany; (M.D.); (S.B.)
- Department of Biology, University of California, San Diego, La Jolla, CA 92083, USA
| | - Anne Günther
- Center for Molecular Neurobiology Hamburg, University Medical Center Hamburg-Eppendorf, Falkenried 94, 20251 Hamburg, Germany;
| | - Rodrigo Lerchundi
- Institute of Neurobiology, Heinrich Heine University Düsseldorf, Universitätsstraße 1, 40225 Düsseldorf, Germany; (R.L.); (C.R.R.)
| | - Christine R. Rose
- Institute of Neurobiology, Heinrich Heine University Düsseldorf, Universitätsstraße 1, 40225 Düsseldorf, Germany; (R.L.); (C.R.R.)
| | - Sabine Balfanz
- Forschungszentrum Jülich, Institute of Biological Information Processing, IBI-1, Leo-Brandt-Straße, 52428 Jülich, Germany; (M.D.); (S.B.)
| | - Arnd Baumann
- Forschungszentrum Jülich, Institute of Biological Information Processing, IBI-1, Leo-Brandt-Straße, 52428 Jülich, Germany; (M.D.); (S.B.)
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21
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Passlick S, Rose CR, Petzold GC, Henneberger C. Disruption of Glutamate Transport and Homeostasis by Acute Metabolic Stress. Front Cell Neurosci 2021; 15:637784. [PMID: 33603647 PMCID: PMC7884476 DOI: 10.3389/fncel.2021.637784] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Accepted: 01/11/2021] [Indexed: 01/02/2023] Open
Abstract
High-affinity, Na+-dependent glutamate transporters are the primary means by which synaptically released glutamate is removed from the extracellular space. They restrict the spread of glutamate from the synaptic cleft into the perisynaptic space and reduce its spillover to neighboring synapses. Thereby, glutamate uptake increases the spatial precision of synaptic communication. Its dysfunction and the entailing rise of the extracellular glutamate concentration accompanied by an increased spread of glutamate result in a loss of precision and in enhanced excitation, which can eventually lead to neuronal death via excitotoxicity. Efficient glutamate uptake depends on a negative resting membrane potential as well as on the transmembrane gradients of the co-transported ions (Na+, K+, and H+) and thus on the proper functioning of the Na+/K+-ATPase. Consequently, numerous studies have documented the impact of an energy shortage, as occurring for instance during an ischemic stroke, on glutamate clearance and homeostasis. The observations range from rapid changes in the transport activity to altered expression of glutamate transporters. Notably, while astrocytes account for the majority of glutamate uptake under physiological conditions, they may also become a source of extracellular glutamate elevation during metabolic stress. However, the mechanisms of the latter phenomenon are still under debate. Here, we review the recent literature addressing changes of glutamate uptake and homeostasis triggered by acute metabolic stress, i.e., on a timescale of seconds to minutes.
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Affiliation(s)
- Stefan Passlick
- Institute of Cellular Neurosciences, Medical Faculty, University of Bonn, Bonn, Germany
| | - Christine R Rose
- Institute of Neurobiology, Faculty of Mathematics and Natural Sciences, Heinrich Heine University Duesseldorf, Duesseldorf, Germany
| | - Gabor C Petzold
- German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany.,Division of Vascular Neurology, University Hospital Bonn, Bonn, Germany
| | - Christian Henneberger
- Institute of Cellular Neurosciences, Medical Faculty, University of Bonn, Bonn, Germany.,German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany.,Institute of Neurology, University College London, London, United Kingdom
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22
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Perez C, Felix L, Durry S, Rose CR, Ullah G. On the origin of ultraslow spontaneous Na + fluctuations in neurons of the neonatal forebrain. J Neurophysiol 2020; 125:408-425. [PMID: 33236936 DOI: 10.1152/jn.00373.2020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Spontaneous neuronal and astrocytic activity in the neonate forebrain is believed to drive the maturation of individual cells and their integration into complex brain-region-specific networks. The previously reported forms include bursts of electrical activity and oscillations in intracellular Ca2+ concentration. Here, we use ratiometric Na+ imaging to demonstrate spontaneous fluctuations in the intracellular Na+ concentration of CA1 pyramidal neurons and astrocytes in tissue slices obtained from the hippocampus of mice at postnatal days 2-4 (P2-4). These occur at very low frequency (∼2/h), can last minutes with amplitudes up to several millimolar, and mostly disappear after the first postnatal week. To further investigate their mechanisms, we model a network consisting of pyramidal neurons and interneurons. Experimentally observed Na+ fluctuations are mimicked when GABAergic inhibition in the simulated network is made depolarizing. Both our experiments and computational model show that blocking voltage-gated Na+ channels or GABAergic signaling significantly diminish the neuronal Na+ fluctuations. On the other hand, blocking a variety of other ion channels, receptors, or transporters including glutamatergic pathways does not have significant effects. Our model also shows that the amplitude and duration of Na+ fluctuations decrease as we increase the strength of glial K+ uptake. Furthermore, neurons with smaller somatic volumes exhibit fluctuations with higher frequency and amplitude. As opposed to this, larger extracellular to intracellular volume ratio observed in neonatal brain exerts a dampening effect. Finally, our model predicts that these periods of spontaneous Na+ influx leave neonatal neuronal networks more vulnerable to seizure-like states when compared with mature brain.NEW & NOTEWORTHY Spontaneous activity in the neonate forebrain plays a key role in cell maturation and brain development. We report spontaneous, ultraslow, asynchronous fluctuations in the intracellular Na+ concentration of neurons and astrocytes. We show that this activity is not correlated with the previously reported synchronous neuronal population bursting or Ca2+ oscillations, both of which occur at much faster timescales. Furthermore, extracellular K+ concentration remains nearly constant. The spontaneous Na+ fluctuations disappear after the first postnatal week.
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Affiliation(s)
- Carlos Perez
- Department of Physics, University of South Florida, Tampa, Florida
| | - Lisa Felix
- Faculty of Mathematics and Natural Sciences, Institute of Neurobiology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Simone Durry
- Faculty of Mathematics and Natural Sciences, Institute of Neurobiology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Christine R Rose
- Faculty of Mathematics and Natural Sciences, Institute of Neurobiology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Ghanim Ullah
- Department of Physics, University of South Florida, Tampa, Florida
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23
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Ona Jodar T, Lage-Rupprecht V, Abraham NM, Rose CR, Egger V. Local Postsynaptic Signaling on Slow Time Scales in Reciprocal Olfactory Bulb Granule Cell Spines Matches Asynchronous Release. Front Synaptic Neurosci 2020; 12:551691. [PMID: 33304264 PMCID: PMC7701096 DOI: 10.3389/fnsyn.2020.551691] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Accepted: 10/19/2020] [Indexed: 11/13/2022] Open
Abstract
In the vertebrate olfactory bulb (OB), axonless granule cells (GC) mediate self- and lateral inhibitory interactions between mitral/tufted cells via reciprocal dendrodendritic synapses. Locally triggered release of GABA from the large reciprocal GC spines occurs on both fast and slow time scales, possibly enabling parallel processing during olfactory perception. Here we investigate local mechanisms for asynchronous spine output. To reveal the temporal and spatial characteristics of postsynaptic ion transients, we imaged spine and adjacent dendrite Ca2 +- and Na+-signals with minimal exogenous buffering by the respective fluorescent indicator dyes upon two-photon uncaging of DNI-glutamate in OB slices from juvenile rats. Both postsynaptic fluorescence signals decayed slowly, with average half durations in the spine head of t1 / 2_Δ[Ca2 +]i ∼500 ms and t1 / 2_Δ[Na+]i ∼1,000 ms. We also analyzed the kinetics of already existing data of postsynaptic spine Ca2 +-signals in response to glomerular stimulation in OB slices from adult mice, either WT or animals with partial GC glutamate receptor deletions (NMDAR: GluN1 subunit; AMPAR: GluA2 subunit). In a large subset of spines the fluorescence signal had a protracted rise time (average time to peak ∼400 ms, range 20 to >1,000 ms). This slow rise was independent of Ca2 + entry via NMDARs, since similarly slow signals occurred in ΔGluN1 GCs. Additional Ca2 + entry in ΔGluA2 GCs (with AMPARs rendered Ca2 +-permeable), however, resulted in larger ΔF/Fs that rose yet more slowly. Thus GC spines appear to dispose of several local mechanisms to promote asynchronous GABA release, which are reflected in the time course of mitral/tufted cell recurrent inhibition.
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Affiliation(s)
- Tiffany Ona Jodar
- Regensburg University, Regensburg, Germany
- Institut D’Investigacions Biomèdiques, Barcelona, Spain
| | - Vanessa Lage-Rupprecht
- Regensburg University, Regensburg, Germany
- Fraunhofer Institute for Algorithms and Scientific Computing, St. Augustin, Germany
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24
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Affiliation(s)
- Nanna MacAulay
- University of Copenhagen, Blegdamsvej 3, Copenhagen, 2200, Denmark
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25
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MacAulay N, Rose CR. CrossTalk opposing view: NKCC1 in the luminal membrane of choroid plexus is outwardly directed under basal conditions and contributes directly to cerebrospinal fluid secretion. J Physiol 2020; 598:4737-4739. [PMID: 32870507 DOI: 10.1113/jp279868] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Affiliation(s)
- N MacAulay
- University of Copenhagen, Blegdamsvej 3, Copenhagen, 2200, Denmark
| | - C R Rose
- Heinrich Heine University, Düsseldorf, Germany
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26
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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: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [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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27
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Felix L, Stephan J, Rose CR. Astrocytes of the early postnatal brain. Eur J Neurosci 2020; 54:5649-5672. [PMID: 32406559 DOI: 10.1111/ejn.14780] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Revised: 04/30/2020] [Accepted: 05/06/2020] [Indexed: 12/21/2022]
Abstract
In the rodent forebrain, the majority of astrocytes are generated during the early postnatal phase. Following differentiation, astrocytes undergo maturation which accompanies the development of the neuronal network. Neonate astrocytes exhibit a distinct morphology and domain size which differs to their mature counterparts. Moreover, many of the plasma membrane proteins prototypical for fully developed astrocytes are only expressed at low levels at neonatal stages. These include connexins and Kir4.1, which define the low membrane resistance and highly negative membrane potential of mature astrocytes. Newborn astrocytes moreover express only low amounts of GLT-1, a glutamate transporter critical later in development. Furthermore, they show specific differences in the properties and spatio-temporal pattern of intracellular calcium signals, resulting from differences in their repertoire of receptors and signalling pathways. Therefore, roles fulfilled by mature astrocytes, including ion and transmitter homeostasis, are underdeveloped in the young brain. Similarly, astrocytic ion signalling in response to neuronal activity, a process central to neuron-glia interaction, differs between the neonate and mature brain. This review describes the unique functional properties of astrocytes in the first weeks after birth and compares them to later stages of development. We conclude that with an immature neuronal network and wider extracellular space, astrocytic support might not be as demanding and critical compared to the mature brain. The delayed differentiation and maturation of astrocytes in the first postnatal weeks might thus reflect a reduced need for active, energy-consuming regulation of the extracellular space and a less tight control of glial feedback onto synaptic transmission.
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Affiliation(s)
- Lisa Felix
- Institute of Neurobiology, Faculty of Mathematics and Natural Sciences, Heinrich Heine University Duesseldorf, Duesseldorf, Germany
| | - Jonathan Stephan
- Institute of Neurobiology, Faculty of Mathematics and Natural Sciences, Heinrich Heine University Duesseldorf, Duesseldorf, Germany
| | - Christine R Rose
- Institute of Neurobiology, Faculty of Mathematics and Natural Sciences, Heinrich Heine University Duesseldorf, Duesseldorf, Germany
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28
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Lerchundi R, Huang N, Rose CR. Quantitative Imaging of Changes in Astrocytic and Neuronal Adenosine Triphosphate Using Two Different Variants of ATeam. Front Cell Neurosci 2020; 14:80. [PMID: 32372916 PMCID: PMC7186936 DOI: 10.3389/fncel.2020.00080] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Accepted: 03/19/2020] [Indexed: 12/25/2022] Open
Abstract
Genetically encoded nanosensors such as the FRET-based adenosine triphosphate (ATP) sensor ATeam enable the measurement of changes in ATP levels inside cells, promoting our understanding of metabolic interactions between astrocytes and neurons. The sensors are usually well characterized in vitro but display altered properties when expressed inside cells, precluding a meaningful conversion of changes in FRET ratios into changes in intracellular ATP concentrations ([ATP]) on the basis of their in vitro properties. Here, we present an experimental strategy for the intracellular calibration of two different variants of ATeam in organotypic tissue slice culture of the mouse brain. After cell-type-specific expression of the sensors in astrocytes or neurons, slices were first perfused with a saline containing the saponin β-escin to permeabilize plasma membranes for ATP. Next, cells were depleted of ATP by perfusion with ATP-free saline containing metabolic inhibitors. Finally, ATP was re-added at defined concentrations and resulting changes in the FRET ratio recorded. When employing this protocol, ATeam1.03 expressed in astrocytes reliably responds to changes in [ATP], exhibiting an apparent KD of 9.4 mM. The high-affinity sensor ATeam1.03YEMK displayed a significantly lower intracellular KD of 2.7 mM. On the basis of these calibrations, we found that induction of a recurrent neuronal network activity resulted in an initial transient increase in astrocytic [ATP] by ~0.12 mM as detected by ATeam1.03YEMK, a result confirmed using ATeam1.03. In neurons, in contrast, [ATP] immediately started to decline upon initiation of a network activity, amounting to a decrease by an average of 0.29 mM after 2 min. Taken together, our results demonstrate that ATeam1.03YEMK and ATeam1.03 display a significant increase in their apparent KD when expressed inside cells as compared with in vitro. Moreover, they show that both ATeam variants enable the quantitative detection of changes of astrocytic and neuronal [ATP] in the physiological range. ATeam1.03YEMK, however, seems preferable because its KD is close to baseline ATP levels. Finally, our data support the idea that synchronized neuronal activity initially stimulates the generation of ATP in astrocytes, presumably through increased glycolysis, whereas ATP levels in neurons decline.
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Affiliation(s)
- Rodrigo Lerchundi
- Institute of Neurobiology, Faculty of Mathematics and Natural Sciences, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Na Huang
- Institute of Neurobiology, Faculty of Mathematics and Natural Sciences, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Christine R Rose
- Institute of Neurobiology, Faculty of Mathematics and Natural Sciences, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
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Rose CR, Ziemens D, Verkhratsky A. On the special role of NCX in astrocytes: Translating Na +-transients into intracellular Ca 2+ signals. Cell Calcium 2019; 86:102154. [PMID: 31901681 DOI: 10.1016/j.ceca.2019.102154] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Revised: 12/02/2019] [Accepted: 12/02/2019] [Indexed: 10/25/2022]
Abstract
As a solute carrier electrogenic transporter, the sodium/calcium exchanger (NCX1-3/SLC8A1-A3) links the trans-plasmalemmal gradients of sodium and calcium ions (Na+, Ca2+) to the membrane potential of astrocytes. Classically, NCX is considered to serve the export of Ca2+ at the expense of the Na+ gradient, defined as a "forward mode" operation. Forward mode NCX activity contributes to Ca2+ extrusion and thus to the recovery from intracellular Ca2+ signals in astrocytes. The reversal potential of the NCX, owing to its transport stoichiometry of 3 Na+ to 1 Ca2+, is, however, close to the astrocytes' membrane potential and hence even small elevations in the astrocytic Na+ concentration or minor depolarisations switch it into the "reverse mode" (Ca2+ import/Na+ export). Notably, transient Na+ elevations in the millimolar range are induced by uptake of glutamate or GABA into astrocytes and/or by the opening of Na+-permeable ion channels in response to neuronal activity. Activity-related Na+ transients result in NCX reversal, which mediates Ca2+ influx from the extracellular space, thereby generating astrocyte Ca2+ signalling independent from InsP3-mediated release from intracellular stores. Under pathological conditions, reverse NCX promotes cytosolic Ca2+ overload, while dampening Na+ elevations of astrocytes. This review provides an overview on our current knowledge about this fascinating transporter and its special functional role in astrocytes. We shall delineate that Na+-driven, reverse NCX-mediated astrocyte Ca2+ signals are involved neurone-glia interaction. Na+ transients, translated by the NCX into Ca2+ elevations, thereby emerge as a new signalling pathway in astrocytes.
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Affiliation(s)
- Christine R Rose
- Institute of Neurobiology, Faculty of Mathematics and Natural Sciences, Heinrich Heine University Duesseldorf, 40225, Duesseldorf, Germany.
| | - Daniel Ziemens
- Institute of Neurobiology, Faculty of Mathematics and Natural Sciences, Heinrich Heine University Duesseldorf, 40225, Duesseldorf, Germany
| | - Alexei Verkhratsky
- Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, M13 9PT, UK; Achucarro Centre for Neuroscience, IKERBASQUE, Basque Foundation for Science, 48011, Bilbao, Spain
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Lerchundi R, Kafitz KW, Färfers M, Beyer F, Huang N, Rose CR. Imaging of Intracellular ATP in Organotypic Tissue Slices of the Mouse Brain using the FRET-based Sensor ATeam1.03YEMK. J Vis Exp 2019. [PMID: 31904744 DOI: 10.3791/60294] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Neuronal activity in the central nervous system (CNS) evokes a high demand on cellular energy provided by the breakdown of adenosine triphosphate (ATP). A large share of ATP is needed to re-install ion gradients across plasma membranes degraded by electrical signaling of neurons. There is evidence that astrocytes - while not generating fast electrical signals themselves - undergo increased production of ATP in response to neuronal activity and support active neurons by providing energy metabolites to them. The recent development of genetically encoded sensors for different metabolites now enables the study of such metabolic interactions between neurons and astrocytes. Here, we describe a protocol for cell-type specific expression of the ATP-sensitive Fluorescence Resonance Energy Transfer- (FRET-) sensor ATeam1.03YEMK in organotypic tissue slice cultures of the mouse hippocampus and cortex using adeno-associated viral vectors (AAV). Furthermore, we demonstrate how this sensor can be employed for dynamic measurement of changes in cellular ATP levels in neurons and astrocytes upon increases in extracellular potassium and following induction of chemical ischemia (i.e., an inhibition of cellular energy metabolism).
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Affiliation(s)
| | - Karl W Kafitz
- Institute of Neurobiology, Heinrich Heine University Düsseldorf
| | - Marcel Färfers
- Institute of Neurobiology, Heinrich Heine University Düsseldorf
| | - Felix Beyer
- Department of Neurology, Düsseldorf University Hospital
| | - Na Huang
- Institute of Neurobiology, Heinrich Heine University Düsseldorf
| | - Christine R Rose
- Institute of Neurobiology, Heinrich Heine University Düsseldorf;
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Verkhratsky A, Rose CR. Na +-dependent transporters: The backbone of astroglial homeostatic function. Cell Calcium 2019; 85:102136. [PMID: 31835178 DOI: 10.1016/j.ceca.2019.102136] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2019] [Revised: 11/30/2019] [Accepted: 11/30/2019] [Indexed: 01/30/2023]
Abstract
Astrocytes are the principal homeostatic cells of the central nerves system (CNS) that support the CNS function at all levels of organisation, from molecular to organ. Several fundamental homeostatic functions of astrocytes are mediated through plasmalemmal pumps and transporters; most of which are also regulated by the transplasmalemmal gradient of Na+ ions. Neuronal activity as well as mechanical or chemical stimulation of astrocytes trigger plasmalemmal Na+ fluxes, which in turn generate spatio-temporally organised transient changes in the cytosolic Na+ concentration, which represent the substrate of astroglial Na+ signalling. Astroglial Na+ signals link and coordinate neuronal activity and CNS homeostatic demands with the astroglial homeostatic response.
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Affiliation(s)
- Alexei Verkhratsky
- Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, M13 9PT, UK; Achucarro Centre for Neuroscience, IKERBASQUE, Basque Foundation for Science, 48011, Bilbao, Spain.
| | - Christine R Rose
- Institute of Neurobiology, Faculty of Mathematics and Natural Sciences, Heinrich Heine University Düsseldorf, Universitätsstrasse 1, D-40225, Düsseldorf, Germany
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Ali AAH, Schwarz-Herzke B, Rollenhagen A, Anstötz M, Holub M, Lübke J, Rose CR, Schnittler HJ, von Gall C. Bmal1-deficiency affects glial synaptic coverage of the hippocampal mossy fiber synapse and the actin cytoskeleton in astrocytes. Glia 2019; 68:947-962. [PMID: 31743496 DOI: 10.1002/glia.23754] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Revised: 10/30/2019] [Accepted: 10/31/2019] [Indexed: 01/13/2023]
Abstract
Bmal1 is an essential component of the molecular clockwork, which drives circadian rhythms in cell function. In Bmal1-deficient (Bmal1-/-) mice, chronodisruption is associated with cognitive deficits and progressive brain pathology including astrocytosis indicated by increased expression of glial fibrillary acidic protein (GFAP). However, relatively little is known about the impact of Bmal1-deficiency on astrocyte morphology prior to astrocytosis. Therefore, in this study we analysed astrocyte morphology in young (6-8 weeks old) adult Bmal1-/- mice. At this age, overall GFAP immunoreactivity was not increased in Bmal1-deficient mice. At the ultrastructural level, we found a decrease in the volume fraction of the fine astrocytic processes that cover the hippocampal mossy fiber synapse, suggesting an impairment of perisynaptic processes and their contribution to neurotransmission. For further analyses of actin cytoskeleton, which is essential for distal process formation, we used cultured Bmal1-/- astrocytes. Bmal1-/- astrocytes showed an impaired formation of actin stress fibers. Moreover, Bmal1-/- astrocytes showed reduced levels of the actin-binding protein cortactin (CTTN). Cttn promoter region contains an E-Box like element and chromatin immunoprecipitation revealed that Cttn is a potential Bmal1 target gene. In addition, the level of GTP-bound (active) Rho-GTPase (Rho-GTP) was reduced in Bmal1-/- astrocytes. In summary, our data demonstrate that Bmal1-deficiency affects morphology of the fine astrocyte processes prior to strong upregulation of GFAP, presumably because of impaired Cttn expression and reduced Rho-GTP activation. These morphological changes might result in altered synaptic function and, thereby, relate to cognitive deficits in chronodisruption.
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Affiliation(s)
- Amira A H Ali
- Institute of Anatomy II, Medical Faculty, Heinrich Heine University, Düsseldorf, Germany
| | - Beryl Schwarz-Herzke
- Institute of Anatomy II, Medical Faculty, Heinrich Heine University, Düsseldorf, Germany
| | - Astrid Rollenhagen
- Institute of Neuroscience and Medicine INM-10, Research Centre Jülich GmbH, Jülich, Germany
| | - Max Anstötz
- Institute of Neuroscience and Medicine INM-10, Research Centre Jülich GmbH, Jülich, Germany
| | - Martin Holub
- Institute of Anatomy II, Medical Faculty, Heinrich Heine University, Düsseldorf, Germany
| | - Joachim Lübke
- Institute of Neuroscience and Medicine INM-10, Research Centre Jülich GmbH, Jülich, Germany.,Department of Psychiatry, Psychotherapy and Psychosomatics, Medical Faculty/RWTH University Hospital Aachen, Aachen, Germany.,Institute of Neuroscience and Medicine INM-10, JARA Translational Brain Medicine, Aachen, Germany
| | - Christine R Rose
- Institute of Neurobiology, Faculty of Mathematics and Natural Sciences, Heinrich Heine University, Düsseldorf, Germany
| | - Hans-Joachim Schnittler
- Institute of Anatomy and Vascular Biology, Medical Faculty, Westfälische Wilhelms University, Münster, Germany
| | - Charlotte von Gall
- Institute of Anatomy II, Medical Faculty, Heinrich Heine University, Düsseldorf, Germany
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Gerkau NJ, Rakers C, Durry S, Petzold GC, Rose CR. Reverse NCX Attenuates Cellular Sodium Loading in Metabolically Compromised Cortex. Cereb Cortex 2019; 28:4264-4280. [PMID: 29136153 DOI: 10.1093/cercor/bhx280] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2017] [Accepted: 10/04/2017] [Indexed: 01/05/2023] Open
Abstract
In core regions of ischemic stroke, disruption of blood flow causes breakdown of ionic gradients and, ultimately, calcium overload and cell death. In the surrounding penumbra, cells may recover upon reperfusion, but recovery is hampered by additional metabolic demands imposed by peri-infarct depolarizations (PIDs). There is evidence that sodium influx drives PIDs, but no data exist on PID-related sodium accumulations in vivo. Here, we found that PIDs in mouse neocortex are associated with propagating sodium elevations in neurons and astrocytes. Similar transient sodium elevations were induced in acute tissue slices by brief chemical ischemia. Blocking NMDA-receptors dampened sodium and accompanying calcium loads of neurons in tissue slices, while inhibiting glutamate transport diminished sodium influx into astrocytes, but amplified neuronal sodium loads. In both cell types, inhibition of sodium/calcium exchange (NCX) increased sodium transients. Blocking NCX also significantly reduced calcium transients, a result confirmed in vivo. Our study provides the first quantitative data on sodium elevations in peri-infarct regions in vivo. They suggest that sodium influx drives reversal of NCX, triggering a massive secondary calcium elevation while promoting export of sodium. Reported neuroprotective effects of NCX activity in stroke models might thus be related to its dampening of ischemia-induced sodium loading.
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Affiliation(s)
- Niklas J Gerkau
- Institute of Neurobiology, Faculty of Mathematics and Natural Sciences, Heinrich Heine University Duesseldorf, Universitaetsstrasse 1, Duesseldorf, Germany
| | - Cordula Rakers
- German Center for Neurodegenerative Diseases (DZNE), Sigmund-Freud-Str. 27, Bonn, Germany
| | - Simone Durry
- Institute of Neurobiology, Faculty of Mathematics and Natural Sciences, Heinrich Heine University Duesseldorf, Universitaetsstrasse 1, Duesseldorf, Germany
| | - Gabor C Petzold
- German Center for Neurodegenerative Diseases (DZNE), Sigmund-Freud-Str. 27, Bonn, Germany.,Department of Neurology, University Hospital Bonn, Sigmund-Freud-Str. 25, Bonn, Germany
| | - Christine R Rose
- Institute of Neurobiology, Faculty of Mathematics and Natural Sciences, Heinrich Heine University Duesseldorf, Universitaetsstrasse 1, Duesseldorf, Germany
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Gerkau NJ, Lerchundi R, Nelson JSE, Lantermann M, Meyer J, Hirrlinger J, Rose CR. Relation between activity-induced intracellular sodium transients and ATP dynamics in mouse hippocampal neurons. J Physiol 2019; 597:5687-5705. [PMID: 31549401 DOI: 10.1113/jp278658] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Accepted: 09/23/2019] [Indexed: 12/17/2022] Open
Abstract
KEY POINTS Employing quantitative Na+ -imaging and Förster resonance energy transfer-based imaging with ATeam1.03YEMK (ATeam), we studied the relation between activity-induced Na+ influx and intracellular ATP in CA1 pyramidal neurons of the mouse hippocampus. Calibration of ATeam in situ enabled a quantitative estimate of changes in intracellular ATP concentrations. Different paradigms of stimulation that induced global Na+ influx into the entire neuron resulted in decreases in [ATP] in the range of 0.1-0.6 mm in somata and dendrites, while Na+ influx that was locally restricted to parts of dendrites did not evoke a detectable change in dendritic [ATP]. Our data suggest that global Na+ transients require global cellular activation of the Na+ /K+ -ATPase resulting in a consumption of ATP that transiently overrides its production. For recovery from locally restricted Na+ influx, ATP production as well as fast intracellular diffusion of ATP and Na+ might prevent a local drop in [ATP]. ABSTRACT Excitatory neuronal activity results in the influx of Na+ through voltage- and ligand-gated channels. Recovery from accompanying increases in intracellular Na+ concentrations ([Na+ ]i ) is mainly mediated by the Na+ /K+ -ATPase (NKA) and is one of the major energy-consuming processes in the brain. Here, we analysed the relation between different patterns of activity-induced [Na+ ]i signalling and ATP in mouse hippocampal CA1 pyramidal neurons by Na+ imaging with sodium-binding benzofurane isophthalate (SBFI) and employing the genetically encoded nanosensor ATeam1.03YEMK (ATeam). In situ calibrations demonstrated a sigmoidal dependence of the ATeam Förster resonance energy transfer ratio on the intracellular ATP concentration ([ATP]i ) with an apparent KD of 2.6 mm, indicating its suitability for [ATP]i measurement. Induction of recurrent network activity resulted in global [Na+ ]i oscillations with amplitudes of ∼10 mm, encompassing somata and dendrites. These were accompanied by a steady decline in [ATP]i by 0.3-0.4 mm in both compartments. Global [Na+ ]i transients, induced by afferent fibre stimulation or bath application of glutamate, caused delayed, transient decreases in [ATP]i as well. Brief focal glutamate application that evoked transient local Na+ influx into a dendrite, however, did not result in a measurable reduction in [ATP]i . Our results suggest that ATP consumption by the NKA following global [Na+ ]i transients temporarily overrides its availability, causing a decrease in [ATP]i . Locally restricted Na+ transients, however, do not result in detectable changes in local [ATP]i , suggesting that ATP production, together with rapid intracellular diffusion of both ATP and Na+ from and to unstimulated neighbouring regions, counteracts a local energy shortage under these conditions.
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Affiliation(s)
- Niklas J Gerkau
- Institute of Neurobiology, Faculty of Mathematics and Natural Sciences, Heinrich Heine University Duesseldorf, 40225, Duesseldorf, Germany
| | - Rodrigo Lerchundi
- Institute of Neurobiology, Faculty of Mathematics and Natural Sciences, Heinrich Heine University Duesseldorf, 40225, Duesseldorf, Germany
| | - Joel S E Nelson
- Institute of Neurobiology, Faculty of Mathematics and Natural Sciences, Heinrich Heine University Duesseldorf, 40225, Duesseldorf, Germany
| | - Marina Lantermann
- Institute of Neurobiology, Faculty of Mathematics and Natural Sciences, Heinrich Heine University Duesseldorf, 40225, Duesseldorf, Germany
| | - Jan Meyer
- Institute of Neurobiology, Faculty of Mathematics and Natural Sciences, Heinrich Heine University Duesseldorf, 40225, Duesseldorf, Germany
| | - Johannes Hirrlinger
- Carl-Ludwig-Institute for Physiology, University of Leipzig, 04103, Leipzig, Germany.,Department of Neurogenetics, Max-Planck-Institute for Experimental Medicine, 37075, Goettingen, Germany
| | - Christine R Rose
- Institute of Neurobiology, Faculty of Mathematics and Natural Sciences, Heinrich Heine University Duesseldorf, 40225, Duesseldorf, Germany
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35
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Meyer J, Untiet V, Fahlke C, Gensch T, Rose CR. Quantitative determination of cellular [Na +] by fluorescence lifetime imaging with CoroNaGreen. J Gen Physiol 2019; 151:1319-1331. [PMID: 31597684 PMCID: PMC6829561 DOI: 10.1085/jgp.201912404] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Accepted: 09/11/2019] [Indexed: 12/23/2022] Open
Abstract
Meyer et al. establish the suitability of the sodium-sensitive indicator dye CoroNaGreen for fluorescence lifetime imaging inside cells. This approach represents a valuable tool for quantitative and dynamic determination of intracellular sodium concentrations independent of dye concentration. Fluorescence lifetime imaging microscopy (FLIM) with fluorescent ion sensors enables the measurement of ion concentrations based on the detection of photon emission events after brief excitation with a pulsed laser source. In contrast to intensity-based imaging, it is independent of dye concentration, photobleaching, or focus drift and has thus been successfully employed for quantitative analysis of, e.g., calcium levels in different cell types and cellular microdomains. Here, we tested the suitability of CoroNaGreen for FLIM-based determination of sodium concentration ([Na+]) inside cells. In vitro measurements confirmed that fluorescence lifetimes of CoroNaGreen (CoroNaFL) increased with increasing [Na+]. Moreover, CoroNaFL was largely independent of changes in potassium concentration or viscosity. Changes in pH slightly affected FL in the acidic range (pH ≤ 5.5). For intracellular determination of [Na+], HEK293T cells were loaded with the membrane-permeable form of CoroNaGreen. Fluorescence decay curves of CoroNaGreen, derived from time-correlated single-photon counting, were approximated by a bi-exponential decay. In situ calibrations revealed a sigmoidal dependence of CoroNaFL on [Na+] between 0 and 150 mM, exhibiting an apparent Kd of ∼80 mM. Based on these calibrations, a [Na+] of 17.6 mM was determined in the cytosol. Cellular nuclei showed a significantly lower [Na+] of 13.0 mM, whereas [Na+] in perinuclear regions was significantly higher (26.5 mM). Metabolic inhibition or blocking the Na+/K+-ATPase by removal of extracellular K+ caused significant [Na+] increases in all cellular subcompartments. Using an alternative approach for data analysis (“Ratio FLIM”) increased the temporal resolution and revealed a sequential response to K+ removal, with cytosolic [Na+] increasing first, followed by the nucleus and finally the perinuclear regions. Taken together, our results show that CoroNaGreen is suitable for dynamic, FLIM-based determination of intracellular [Na+]. This approach thus represents a valuable tool for quantitative determination of [Na+] and changes thereof in different subcellular compartments.
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Affiliation(s)
- Jan Meyer
- Institute of Neurobiology, Faculty of Mathematics and Natural Sciences, Heinrich Heine University Düsseldorf, Düsseldorf, Germany.,Institute of Complex Systems 4 (ICS-4), Zelluläre Biophysik, Forschungszentrum Jülich, Jülich, Germany
| | - Verena Untiet
- Institute of Complex Systems 4 (ICS-4), Zelluläre Biophysik, Forschungszentrum Jülich, Jülich, Germany
| | - Christoph Fahlke
- Institute of Complex Systems 4 (ICS-4), Zelluläre Biophysik, Forschungszentrum Jülich, Jülich, Germany
| | - Thomas Gensch
- Institute of Complex Systems 4 (ICS-4), Zelluläre Biophysik, Forschungszentrum Jülich, Jülich, Germany
| | - Christine R Rose
- Institute of Neurobiology, Faculty of Mathematics and Natural Sciences, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
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Abstract
Astrocytes are homeostatic and protective cells of the central nervous system. Astroglial homeostatic responses are tightly coordinated with neuronal activity. Astrocytes maintain neuronal excitability through regulation of extracellular ion concentrations, as well as assisting and modulating synaptic transmission by uptake and catabolism of major neurotransmitters. Moreover, they support neuronal metabolism and detoxify ammonium and reactive oxygen species. Astroglial homeostatic actions are initiated and controlled by intercellular signalling of ions, including Ca2+ , Na+ , Cl- , H+ and possibly K+ . This review summarises current knowledge on ionic signals mediated by the major monovalent ions, which occur in microdomains, as global events, or as propagating intercellular waves and thereby represent the substrate for astroglial excitability.
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Affiliation(s)
- Alexei Verkhratsky
- Faculty of Biology, Medicine and Health, The University of Manchester, M13 9PT, Manchester, UK.,Centre for Basic and Translational Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, 2200, Copenhagen, Denmark.,Achucarro Centre for Neuroscience, IKERBASQUE, Basque Foundation for Science, 48011, Bilbao, Spain
| | - Verena Untiet
- Centre for Basic and Translational Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, 2200, Copenhagen, Denmark
| | - Christine R Rose
- Institute of Neurobiology, Faculty of Mathematics and Natural Sciences, Heinrich Heine University Düsseldorf, Universitätsstrasse 1, D-40225, Düsseldorf, Germany
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37
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Abstract
The use of fluorescent chemical indicator dyes enables the dynamic and quantitative imaging of intracellular sodium concentrations and activity-related sodium transients in astrocytes.Here we describe different approaches for the loading of cellular networks or single astrocytes with sodium-sensitive indicators in brain tissue. Fluorescence signals can then be detected and analyzed with conventional camera-based, wide-field imaging or by employing high-resolution multi-photon microscopy. We furthermore explain strategies for the induction of local and global sodium transients in astrocytes. Finally, we illustrate how fluorescence signals derived from such imaging experiments can be converted into absolute changes of sodium concentration in astrocytes based on an in situ calibration procedure.
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Affiliation(s)
- Niklas J Gerkau
- Institute of Neurobiology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Karl W Kafitz
- Institute of Neurobiology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Christine R Rose
- Institute of Neurobiology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany.
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38
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Lerchundi R, Kafitz KW, Winkler U, Färfers M, Hirrlinger J, Rose CR. FRET-based imaging of intracellular ATP in organotypic brain slices. J Neurosci Res 2018; 97:933-945. [PMID: 30506574 DOI: 10.1002/jnr.24361] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2018] [Revised: 10/29/2018] [Accepted: 11/13/2018] [Indexed: 12/24/2022]
Abstract
Active neurons require a substantial amount of adenosine triphosphate (ATP) to re-establish ion gradients degraded by ion flux across their plasma membranes. Despite this fact, neurons, in contrast to astrocytes, do not contain any significant stores of energy substrates. Recent work has provided evidence for a neuro-metabolic coupling between both cell types, in which increased glycolysis and lactate production in astrocytes support neuronal metabolism. Here, we established the cell type-specific expression of the Förster resonance energy transfer (FRET) based nanosensor ATeam1.03YEMK ("Ateam") for dynamic measurement of changes in intracellular ATP levels in organotypic brain tissue slices. To this end, adeno-associated viral vectors coding for Ateam, driven by either the synapsin- or glial fibrillary acidic protein (GFAP) promoter were employed for specific transduction of neurons or astrocytes, respectively. Chemical ischemia, induced by perfusion of tissue slices with metabolic inhibitors of cellular glycolysis and mitochondrial respiration, resulted in a rapid decrease in the cellular Ateam signal to a new, low level, indicating nominal depletion of intracellular ATP. Increasing the extracellular potassium concentration to 8 mM, thereby mimicking the release of potassium from active neurons, did not alter ATP levels in neurons. It, however, caused in an increase in ATP levels in astrocytes, a result which was confirmed in acutely isolated tissue slices. In summary, our results demonstrate that organotypic cultured slices are a reliable tool for FRET-based dynamic imaging of ATP in neurons and astrocytes. They moreover provide evidence for an increased ATP synthesis in astrocytes, but not neurons, during periods of elevated extracellular potassium concentrations.
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Affiliation(s)
- Rodrigo Lerchundi
- Faculty of Mathematics and Natural Sciences, Institute of Neurobiology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Karl W Kafitz
- Faculty of Mathematics and Natural Sciences, Institute of Neurobiology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Ulrike Winkler
- Faculty of Medicine, Carl-Ludwig-Institute for Physiology, University of Leipzig, Leipzig, Germany
| | - Marcel Färfers
- Faculty of Mathematics and Natural Sciences, Institute of Neurobiology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Johannes Hirrlinger
- Faculty of Medicine, Carl-Ludwig-Institute for Physiology, University of Leipzig, Leipzig, Germany.,Department of Neurogenetics, Max-Planck-Institute for Experimental Medicine, Göttingen, Germany
| | - Christine R Rose
- Faculty of Mathematics and Natural Sciences, Institute of Neurobiology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
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39
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Wadle SL, Augustin V, Langer J, Jabs R, Philippot C, Weingarten DJ, Rose CR, Steinhäuser C, Stephan J. Anisotropic Panglial Coupling Reflects Tonotopic Organization in the Inferior Colliculus. Front Cell Neurosci 2018; 12:431. [PMID: 30542265 PMCID: PMC6277822 DOI: 10.3389/fncel.2018.00431] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Accepted: 10/31/2018] [Indexed: 12/17/2022] Open
Abstract
Astrocytes and oligodendrocytes in different brain regions form panglial networks and the topography of such networks can correlate with neuronal topography and function. Astrocyte-oligodendrocyte networks in the lateral superior olive (LSO)-an auditory brainstem nucleus-were found to be anisotropic with a preferred orientation orthogonally to the tonotopic axis. We hypothesized that such a specialization might be present in other tonotopically organized brainstem nuclei, too. Thus, we analyzed gap junctional coupling in the center of the inferior colliculus (IC)-another nucleus of the auditory brainstem that exhibits tonotopic organization. In acute brainstem slices obtained from mice, IC networks were traced employing whole-cell patch-clamp recordings of single sulforhodamine (SR) 101-identified astrocytes and concomitant intracellular loading of the gap junction-permeable tracer neurobiotin. The majority of dye-coupled networks exhibited an oval topography, which was preferentially oriented orthogonal to the tonotopic axis. Astrocyte processes showed preferentially the same orientation indicating a correlation between astrocyte and network topography. In addition to SR101-positive astrocytes, IC networks contained oligodendrocytes. Using Na+ imaging, we analyzed the capability of IC networks to redistribute small ions. Na+ bi-directionally diffused between SR101-positive astrocytes and SR101-negative cells-presumably oligodendrocytes-showing the functionality of IC networks. Taken together, our results demonstrate that IC astrocytes and IC oligodendrocytes form functional anisotropic panglial networks that are preferentially oriented orthogonal to the tonotopic axis. Thus, our data indicate that the topographic specialization of glial networks seen in IC and LSO might be a general feature of tonotopically organized auditory brainstem nuclei.
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Affiliation(s)
- Simon L Wadle
- Animal Physiology Group, Department of Biology, University of Kaiserslautern, Kaiserslautern, Germany
| | - Vanessa Augustin
- Animal Physiology Group, Department of Biology, University of Kaiserslautern, Kaiserslautern, Germany
| | - Julia Langer
- Institute of Neurobiology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Ronald Jabs
- Institute of Cellular Neurosciences, Medical Faculty, University of Bonn, Bonn, Germany
| | - Camille Philippot
- Institute of Cellular Neurosciences, Medical Faculty, University of Bonn, Bonn, Germany
| | - Dennis J Weingarten
- Animal Physiology Group, Department of Biology, University of Kaiserslautern, Kaiserslautern, Germany
| | - Christine R Rose
- Institute of Neurobiology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Christian Steinhäuser
- Institute of Cellular Neurosciences, Medical Faculty, University of Bonn, Bonn, Germany
| | - Jonathan Stephan
- Animal Physiology Group, Department of Biology, University of Kaiserslautern, Kaiserslautern, Germany
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Steffensen AB, Oernbo EK, Stoica A, Gerkau NJ, Barbuskaite D, Tritsaris K, Rose CR, MacAulay N. Cotransporter-mediated water transport underlying cerebrospinal fluid formation. Nat Commun 2018; 9:2167. [PMID: 29867199 PMCID: PMC5986890 DOI: 10.1038/s41467-018-04677-9] [Citation(s) in RCA: 103] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Accepted: 05/14/2018] [Indexed: 12/20/2022] Open
Abstract
Cerebrospinal fluid (CSF) production occurs at a rate of 500 ml per day in the adult human. Conventional osmotic forces do not suffice to support such production rate and the molecular mechanisms underlying this fluid production remain elusive. Using ex vivo choroid plexus live imaging and isotope flux in combination with in vivo CSF production determination in mice, we identify a key component in the CSF production machinery. The Na+/K+/2Cl− cotransporter (NKCC1) expressed in the luminal membrane of choroid plexus contributes approximately half of the CSF production, via its unusual outward transport direction and its unique ability to directly couple water transport to ion translocation. We thereby establish the concept of cotransport of water as a missing link in the search for molecular pathways sustaining CSF production and redefine the current model of this pivotal physiological process. Our results provide a rational pharmacological target for pathologies involving disturbed brain fluid dynamics. Osmotic forces do not suffice to explain the rate of cerebrospinal fluid (CSF) production. Here, the authors show that the Na+/K+/2Cl− cotransporter in the choroid plexus contributes substantially to CSF production via its inherent ability to cotransport water.
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Affiliation(s)
- Annette B Steffensen
- Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Noerre Allé 14, 2200, Copenhagen, Denmark
| | - Eva K Oernbo
- Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Noerre Allé 14, 2200, Copenhagen, Denmark
| | - Anca Stoica
- Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Noerre Allé 14, 2200, Copenhagen, Denmark
| | - Niklas J Gerkau
- Institute of Neurobiology, Heinrich Heine University Duesseldorf, Universitaetsstrasse 1, 40225, Duesseldorf, Germany
| | - Dagne Barbuskaite
- Department of Cellular and Molecular Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Noerre Allé 14, 2200, Copenhagen, Denmark
| | - Katerina Tritsaris
- Department of Cellular and Molecular Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Noerre Allé 14, 2200, Copenhagen, Denmark
| | - Christine R Rose
- Institute of Neurobiology, Heinrich Heine University Duesseldorf, Universitaetsstrasse 1, 40225, Duesseldorf, Germany
| | - Nanna MacAulay
- Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Noerre Allé 14, 2200, Copenhagen, Denmark.
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Petrik D, Myoga MH, Grade S, Gerkau NJ, Pusch M, Rose CR, Grothe B, Götz M. Epithelial Sodium Channel Regulates Adult Neural Stem Cell Proliferation in a Flow-Dependent Manner. Cell Stem Cell 2018; 22:865-878.e8. [DOI: 10.1016/j.stem.2018.04.016] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Revised: 02/16/2018] [Accepted: 04/17/2018] [Indexed: 12/22/2022]
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Affiliation(s)
- Christine R Rose
- Institute of Neurobiology, Faculty of Mathematics and Natural Sciences, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Alexei Verkhratsky
- Faculty of Life Sciences, The University of Manchester, Manchester, United Kingdom
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Rose CR, Felix L, Zeug A, Dietrich D, Reiner A, Henneberger C. Astroglial Glutamate Signaling and Uptake in the Hippocampus. Front Mol Neurosci 2018; 10:451. [PMID: 29386994 PMCID: PMC5776105 DOI: 10.3389/fnmol.2017.00451] [Citation(s) in RCA: 122] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Accepted: 12/22/2017] [Indexed: 12/22/2022] Open
Abstract
Astrocytes have long been regarded as essentially unexcitable cells that do not contribute to active signaling and information processing in the brain. Contrary to this classical view, it is now firmly established that astrocytes can specifically respond to glutamate released from neurons. Astrocyte glutamate signaling is initiated upon binding of glutamate to ionotropic and/or metabotropic receptors, which can result in calcium signaling, a major form of glial excitability. Release of so-called gliotransmitters like glutamate, ATP and D-serine from astrocytes in response to activation of glutamate receptors has been demonstrated to modulate various aspects of neuronal function in the hippocampus. In addition to receptors, glutamate binds to high-affinity, sodium-dependent transporters, which results in rapid buffering of synaptically-released glutamate, followed by its removal from the synaptic cleft through uptake into astrocytes. The degree to which astrocytes modulate and control extracellular glutamate levels through glutamate transporters depends on their expression levels and on the ionic driving forces that decrease with ongoing activity. Another major determinant of astrocytic control of glutamate levels could be the precise morphological arrangement of fine perisynaptic processes close to synapses, defining the diffusional distance for glutamate, and the spatial proximity of transporters in relation to the synaptic cleft. In this review, we will present an overview of the mechanisms and physiological role of glutamate-induced ion signaling in astrocytes in the hippocampus as mediated by receptors and transporters. Moreover, we will discuss the relevance of astroglial glutamate uptake for extracellular glutamate homeostasis, focusing on how activity-induced dynamic changes of perisynaptic processes could shape synaptic transmission at glutamatergic synapses.
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Affiliation(s)
- Christine R Rose
- Institute of Neurobiology, Faculty of Mathematics and Natural Sciences, Heinrich Heine University Duesseldorf, Duesseldorf, Germany
| | - Lisa Felix
- Institute of Neurobiology, Faculty of Mathematics and Natural Sciences, Heinrich Heine University Duesseldorf, Duesseldorf, Germany
| | - Andre Zeug
- Cellular Neurophysiology, Hannover Medical School, Hannover, Germany
| | - Dirk Dietrich
- Department of Neurosurgery, University of Bonn Medical School, Bonn, Germany
| | - Andreas Reiner
- Cellular Neurobiology, Faculty of Biology and Biotechnology, Ruhr University Bochum, Bochum, Germany
| | - Christian Henneberger
- Institute of Cellular Neurosciences, University of Bonn Medical School, Bonn, Germany.,German Center for Degenerative Diseases (DZNE), Bonn, Germany.,Institute of Neurology, University College London, London, United Kingdom
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Hesse J, Leberling S, Boden E, Friebe D, Schmidt T, Ding Z, Dieterich P, Deussen A, Roderigo C, Rose CR, Floss DM, Scheller J, Schrader J. CD73-derived adenosine and tenascin-C control cytokine production by epicardium-derived cells formed after myocardial infarction. FASEB J 2017; 31:3040-3053. [PMID: 28363952 DOI: 10.1096/fj.201601307r] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2016] [Accepted: 03/13/2017] [Indexed: 01/29/2023]
Abstract
Epicardium-derived cells (EPDCs) play a fundamental role in embryonic cardiac development and are reactivated in the adult heart in response to myocardial infarction (MI). In this study, EPDCs from post-MI rat hearts highly expressed the ectoenzyme CD73 and secreted the profibrotic matricellular protein tenascin-C (TNC). CD73 on EPDCs extensively generated adenosine from both extracellular ATP and NAD. This in turn stimulated the release of additional nucleotides from a Brefeldin A-sensitive intracellular pool via adenosine-A2BR signaling, forming a positive-feedback loop. A2BR activation, in addition, strongly promoted the release of major regulatory cytokines, such as IL-6, IL-11, and VEGF. TNC was found to stimulate EPDC migration and, together with ATP-P2X7R signaling, to activate inflammasomes in EPDCs via TLR4. Our results demonstrate that EPDCs are an important source of various proinflammatory factors in the post-MI heart controlled by purinergic and TNC signaling.-Hesse, J., Leberling, S., Boden, E., Friebe, D., Schmidt, T., Ding, Z., Dieterich, P., Deussen, A., Roderigo, C., Rose, C. R., Floss, D. M., Scheller, J., Schrader, J. CD73-derived adenosine and tenascin-C control cytokine production by epicardium-derived cells formed after myocardial infarction.
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Affiliation(s)
- Julia Hesse
- Department of Molecular Cardiology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Stella Leberling
- Department of Molecular Cardiology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Elisabeth Boden
- Department of Molecular Cardiology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Daniela Friebe
- Department of Molecular Cardiology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Timo Schmidt
- Department of Molecular Cardiology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Zhaoping Ding
- Department of Molecular Cardiology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Peter Dieterich
- Institute of Physiology, Medical Faculty Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
| | - Andreas Deussen
- Institute of Physiology, Medical Faculty Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
| | - Claudia Roderigo
- Institute of Neurobiology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Christine R Rose
- Institute of Neurobiology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Doreen M Floss
- Institute of Biochemistry and Molecular Biology II, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Jürgen Scheller
- Institute of Biochemistry and Molecular Biology II, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Jürgen Schrader
- Department of Molecular Cardiology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany;
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Ona-Jodar T, Gerkau NJ, Sara Aghvami S, Rose CR, Egger V. Two-Photon Na + Imaging Reports Somatically Evoked Action Potentials in Rat Olfactory Bulb Mitral and Granule Cell Neurites. Front Cell Neurosci 2017; 11:50. [PMID: 28293175 PMCID: PMC5329072 DOI: 10.3389/fncel.2017.00050] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2016] [Accepted: 02/14/2017] [Indexed: 12/05/2022] Open
Abstract
Dendrodendritic synaptic interactions are a hallmark of neuronal processing in the vertebrate olfactory bulb. Many classes of olfactory bulb neurons including the principal mitral cells (MCs) and the axonless granule cells (GCs) dispose of highly efficient propagation of action potentials (AP) within their dendrites, from where they can release transmitter onto each other. So far, backpropagation in GC dendrites has been investigated indirectly via Ca2+ imaging. Here, we used two-photon Na+ imaging to directly report opening of voltage-gated sodium channels due to AP propagation in both cell types. To this end, neurons in acute slices from juvenile rat bulbs were filled with 1 mM SBFI via whole-cell patch-clamp. Calibration of SBFI signals revealed that a change in fluorescence ΔF/F by 10% corresponded to a Δ[Na+]i of ∼22 mM. We then imaged proximal axon segments of MCs during somatically evoked APs (sAP). While single sAPs were detectable in ∼50% of axons, trains of 20 sAPs at 50 Hz always resulted in substantial ΔF/F of ∼15% (∼33 mM Δ[Na+]i). ΔF/F was significantly larger for 80 Hz vs. 50 Hz trains, and decayed with half-durations τ1/2 ∼0.6 s for both frequencies. In MC lateral dendrites, AP trains yielded small ΔF/F of ∼3% (∼7 mM Δ[Na+]i). In GC apical dendrites and adjacent spines, single sAPs were not detectable. Trains resulted in an average dendritic ΔF/F of 7% (16 mM Δ[Na+]i) with τ1/2 ∼1 s, similar for 50 and 80 Hz. Na+ transients were indistinguishable between large GC spines and their adjacent dendrites. Cell-wise analysis revealed two classes of GCs with the first showing a decrease in ΔF/F along the dendrite with distance from the soma and the second an increase. These classes clustered with morphological parameters. Simulations of Δ[Na+]i replicated these behaviors via negative and positive gradients in Na+ current density, assuming faithful AP backpropagation. Such specializations of dendritic excitability might confer specific temporal processing capabilities to bulbar principal cell-GC subnetworks. In conclusion, we show that Na+ imaging provides a valuable tool for characterizing AP invasion of MC axons and GC dendrites and spines.
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Affiliation(s)
- Tiffany Ona-Jodar
- Neurophysiology, Institute of Zoology, Universität Regensburg Regensburg, Germany
| | - Niklas J Gerkau
- Institute of Neurobiology, Heinrich-Heine-Universität Düsseldorf Düsseldorf, Germany
| | - S Sara Aghvami
- Neurophysiology, Institute of Zoology, Universität RegensburgRegensburg, Germany; School of Electrical and Computer Engineering, University of TehranTehran, Iran; School of Cognitive Science, Institute for Research in Fundamental ScienceTehran, Iran
| | - Christine R Rose
- Institute of Neurobiology, Heinrich-Heine-Universität Düsseldorf Düsseldorf, Germany
| | - Veronica Egger
- Neurophysiology, Institute of Zoology, Universität RegensburgRegensburg, Germany; Regensburg Center of Neuroscience, Universität RegensburgRegensburg, Germany
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Gerkau NJ, Rakers C, Petzold GC, Rose CR. Differential effects of energy deprivation on intracellular sodium homeostasis in neurons and astrocytes. J Neurosci Res 2017; 95:2275-2285. [PMID: 28150887 DOI: 10.1002/jnr.23995] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2016] [Revised: 11/10/2016] [Accepted: 11/10/2016] [Indexed: 12/11/2022]
Abstract
The maintenance of a low intracellular sodium concentration by the Na+ /K+ -ATPase (NKA) is critical for brain function. In both neurons and glial cells, NKA activity is required to counteract changes in the sodium gradient due to opening of voltage- and ligand-gated channels and/or activation of sodium-dependent secondary active transporters. Because NKA consumes about 50% of cellular ATP, sodium homeostasis is strictly dependent on an intact cellular energy metabolism. Despite the high energetic costs of electrical signaling, neurons do not contain significant energy stores themselves, but rely on a close metabolic interaction with surrounding astrocytes. A disruption of energy supply as observed during focal ischemia causes a rapid drop in ATP in both neurons and astrocytes. There is accumulating evidence that dysregulation of intracellular sodium is an inherent consequence of a reduction in cellular ATP, triggering secondary failure of extra- and intracellular homeostasis of other ions -in particular potassium, calcium, and protons- and thereby promoting excitotoxicity. The characteristics, cellular mechanisms and direct consequences of harmful sodium influx, however, differ between neurons and astrocytes. Moreover, recent work has shown that an intact astrocyte metabolism and sodium homeostasis are critical to maintain the sodium homeostasis of surrounding neurons as well as their capacity to recover from imposed sodium influx. Understanding the mechanisms of sodium increases upon metabolic failure and the differential responses of neurons and glial cells as well as their metabolic interactions will be critical to fully unravel the events causing cellular malfunction, failure and cell death following energy depletion. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Niklas J Gerkau
- Institute of Neurobiology, Faculty of Mathematics and Natural Sciences, Heinrich Heine University Düsseldorf, Universitätsstrasse 1, D-40225, Düsseldorf, Germany
| | - Cordula Rakers
- German Center for Neurodegenerative Diseases (DZNE), Sigmund-Freud-Strasse 27, 53127, Bonn, Germany
| | - Gabor C Petzold
- German Center for Neurodegenerative Diseases (DZNE), Sigmund-Freud-Strasse 27, 53127, Bonn, Germany
| | - Christine R Rose
- Institute of Neurobiology, Faculty of Mathematics and Natural Sciences, Heinrich Heine University Düsseldorf, Universitätsstrasse 1, D-40225, Düsseldorf, Germany
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Rose CR, Ziemens D, Untiet V, Fahlke C. Molecular and cellular physiology of sodium-dependent glutamate transporters. Brain Res Bull 2016; 136:3-16. [PMID: 28040508 DOI: 10.1016/j.brainresbull.2016.12.013] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Revised: 12/20/2016] [Accepted: 12/21/2016] [Indexed: 02/04/2023]
Abstract
Glutamate is the major excitatory transmitter in the vertebrate brain. After its release from presynaptic nerve terminals, it is rapidly taken up by high-affinity sodium-dependent plasma membrane transporters. While both neurons and glial cells express these excitatory amino acid transporters (EAATs), the majority of glutamate uptake is accomplished by astrocytes, which convert synaptically-released glutamate to glutamine or feed it into their own metabolism. Glutamate uptake by astrocytes not only shapes synaptic transmission by regulating the availability of glutamate to postsynaptic neuronal receptors, but also protects neurons from hyper-excitability and subsequent excitotoxic damage. In the present review, we provide an overview of the molecular and cellular characteristics of sodium-dependent glutamate transporters and their associated anion permeation pathways, with a focus on astrocytic glutamate transport. We summarize their functional properties and roles within tripartite synapses under physiological and pathophysiological conditions, exemplifying the intricate interactions and interrelationships between neurons and glial cells in the brain.
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Affiliation(s)
- Christine R Rose
- Institute of Neurobiology, Faculty of Mathematics and Natural Sciences, Heinrich Heine University Düsseldorf, Germany.
| | - Daniel Ziemens
- Institute of Neurobiology, Faculty of Mathematics and Natural Sciences, Heinrich Heine University Düsseldorf, Germany
| | - Verena Untiet
- Institute of Complex Systems, Zelluläre Biophysik (ICS-4), Forschungszentrum Jülich, Germany
| | - Christoph Fahlke
- Institute of Complex Systems, Zelluläre Biophysik (ICS-4), Forschungszentrum Jülich, Germany
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Untiet V, Kovermann P, Gerkau NJ, Gensch T, Rose CR, Fahlke C. Glutamate transporter-associated anion channels adjust intracellular chloride concentrations during glial maturation. Glia 2016; 65:388-400. [PMID: 27859594 DOI: 10.1002/glia.23098] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2016] [Revised: 10/18/2016] [Accepted: 10/24/2016] [Indexed: 01/09/2023]
Abstract
Astrocytic volume regulation and neurotransmitter uptake are critically dependent on the intracellular anion concentration, but little is known about the mechanisms controlling internal anion homeostasis in these cells. Here we used fluorescence lifetime imaging microscopy (FLIM) with the chloride-sensitive dye MQAE to measure intracellular chloride concentrations in murine Bergmann glial cells in acute cerebellar slices. We found Bergmann glial [Cl- ]int to be controlled by two opposing transport processes: chloride is actively accumulated by the Na+ -K+ -2Cl- cotransporter NKCC1, and chloride efflux through anion channels associated with excitatory amino acid transporters (EAATs) reduces [Cl- ]int to values that vary upon changes in expression levels or activity of these channels. EAATs transiently form anion-selective channels during glutamate transport, and thus represent a class of ligand-gated anion channels. Age-dependent upregulation of EAATs results in a developmental chloride switch from high internal chloride concentrations (51.6 ± 2.2 mM, mean ± 95% confidence interval) during early development to adult levels (35.3 ± 0.3 mM). Simultaneous blockade of EAAT1/GLAST and EAAT2/GLT-1 increased [Cl- ]int in adult glia to neonatal values. Moreover, EAAT activation by synaptic stimulations rapidly decreased [Cl- ]int . Other tested chloride channels or chloride transporters do not contribute to [Cl- ]int under our experimental conditions. Neither genetic removal of ClC-2 nor pharmacological block of K+ -Cl- cotransporter change resting Bergmann glial [Cl- ]int in acute cerebellar slices. We conclude that EAAT anion channels play an important and unexpected role in adjusting glial intracellular anion concentration during maturation and in response to cerebellar activity. GLIA 2017;65:388-400.
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Affiliation(s)
- Verena Untiet
- Institute of Complex Systems, Zelluläre Biophysik (ICS-4), Forschungszentrum Jülich, Germany
| | - Peter Kovermann
- Institute of Complex Systems, Zelluläre Biophysik (ICS-4), Forschungszentrum Jülich, Germany
| | - Niklas J Gerkau
- Institute of Neurobiology, Heinrich-Heine-Universität Düsseldorf, Germany
| | - Thomas Gensch
- Institute of Complex Systems, Zelluläre Biophysik (ICS-4), Forschungszentrum Jülich, Germany
| | - Christine R Rose
- Institute of Neurobiology, Heinrich-Heine-Universität Düsseldorf, Germany
| | - Christoph Fahlke
- Institute of Complex Systems, Zelluläre Biophysik (ICS-4), Forschungszentrum Jülich, Germany
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Langer J, Gerkau NJ, Derouiche A, Kleinhans C, Moshrefi-Ravasdjani B, Fredrich M, Kafitz KW, Seifert G, Steinhäuser C, Rose CR. Rapid sodium signaling couples glutamate uptake to breakdown of ATP in perivascular astrocyte endfeet. Glia 2016; 65:293-308. [PMID: 27785828 DOI: 10.1002/glia.23092] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2016] [Revised: 10/05/2016] [Accepted: 10/06/2016] [Indexed: 12/19/2022]
Abstract
Perivascular endfeet of astrocytes are highly polarized compartments that ensheath blood vessels and contribute to the blood-brain barrier. They experience calcium transients with neuronal activity, a phenomenon involved in neurovascular coupling. Endfeet also mediate the uptake of glucose from the blood, a process stimulated in active brain regions. Here, we demonstrate in mouse hippocampal tissue slices that endfeet undergo sodium signaling upon stimulation of glutamatergic synaptic activity. Glutamate-induced endfeet sodium transients were diminished by TFB-TBOA, suggesting that they were generated by sodium-dependent glutamate uptake. With local agonist application, they could be restricted to endfeet and immunohistochemical analysis revealed prominent expression of glutamate transporters GLAST and GLT-1 localized towards the neuropil vs. the vascular side of endfeet. Endfeet sodium signals spread at an apparent maximum velocity of ∼120 µm/s and directly propagated from stimulated into neighboring endfeet; this spread was omitted in Cx30/Cx43 double-deficient mice. Sodium transients resulted in elevation of intracellular magnesium, indicating a decrease in intracellular ATP. In summary, our results establish that excitatory synaptic activity and stimulation of glutamate uptake in astrocytes trigger transient sodium increases in perivascular endfeet which rapidly spread through gap junctions into neighboring endfeet and cause a reduction of intracellular ATP. The newly discovered endfeet sodium signaling thereby represents a fast, long-lived and inter-cellularly acting indicator of synaptic activity at the blood-brain barrier, which likely constitutes an important component of neuro-metabolic coupling in the brain. GLIA 2017;65:293-308.
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Affiliation(s)
- Julia Langer
- Faculty of Mathematics and Natural Sciences, Institute of Neurobiology, Heinrich Heine University Duesseldorf, Universitätsstrasse 1, Duesseldorf, D-40225, Germany
| | - Niklas J Gerkau
- Faculty of Mathematics and Natural Sciences, Institute of Neurobiology, Heinrich Heine University Duesseldorf, Universitätsstrasse 1, Duesseldorf, D-40225, Germany
| | - Amin Derouiche
- Institute of Anatomy II and Dr. Senckenbergisches Chronomedizinisches Institut, Goethe-University of Frankfurt, Theodor-Stern-Kai 7, Frankfurt/M, D-60590, Germany
| | - Christian Kleinhans
- Faculty of Mathematics and Natural Sciences, Institute of Neurobiology, Heinrich Heine University Duesseldorf, Universitätsstrasse 1, Duesseldorf, D-40225, Germany
| | - Behrouz Moshrefi-Ravasdjani
- Faculty of Mathematics and Natural Sciences, Institute of Neurobiology, Heinrich Heine University Duesseldorf, Universitätsstrasse 1, Duesseldorf, D-40225, Germany
| | - Michaela Fredrich
- Institute of Anatomy II and Dr. Senckenbergisches Chronomedizinisches Institut, Goethe-University of Frankfurt, Theodor-Stern-Kai 7, Frankfurt/M, D-60590, Germany
| | - Karl W Kafitz
- Faculty of Mathematics and Natural Sciences, Institute of Neurobiology, Heinrich Heine University Duesseldorf, Universitätsstrasse 1, Duesseldorf, D-40225, Germany
| | - Gerald Seifert
- Medical Faculty, Institute of Cellular Neurosciences, University of Bonn, Bonn, D-53105, Germany
| | - Christian Steinhäuser
- Medical Faculty, Institute of Cellular Neurosciences, University of Bonn, Bonn, D-53105, Germany
| | - Christine R Rose
- Faculty of Mathematics and Natural Sciences, Institute of Neurobiology, Heinrich Heine University Duesseldorf, Universitätsstrasse 1, Duesseldorf, D-40225, Germany
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Mondragão MA, Schmidt H, Kleinhans C, Langer J, Kafitz KW, Rose CR. Extrusion versus diffusion: mechanisms for recovery from sodium loads in mouse CA1 pyramidal neurons. J Physiol 2016; 594:5507-27. [PMID: 27080107 PMCID: PMC5043027 DOI: 10.1113/jp272431] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2016] [Accepted: 04/07/2016] [Indexed: 12/20/2022] Open
Abstract
KEY POINTS Neuronal activity causes local or global sodium signalling in neurons, depending on the pattern of synaptic activity. Recovery from global sodium loads critically relies on Na(+) /K(+) -ATPase and an intact energy metabolism in both somata and dendrites. For recovery from local sodium loads in dendrites, Na(+) /K(+) -ATPase activity is not required per se. Instead, recovery is predominately mediated by lateral diffusion, exhibiting rates that are 10-fold higher than for global sodium signals. Recovery from local dendritic sodium increases is still efficient during short periods of energy deprivation, indicating that fast diffusion of sodium to non-stimulated regions strongly reduces local energy requirements. ABSTRACT Excitatory activity is accompanied by sodium influx into neurones as a result of the opening of voltage- and ligand-activated channels. Recovery from resulting sodium transients has mainly been attributed to Na(+) /K(+) -ATPase (NKA). Because sodium ions are highly mobile, diffusion could provide an additional pathway. We tested this in hippocampal neurones using whole-cell patch-clamp recordings and sodium imaging. Somatic sodium transients induced by local glutamate application recovered at a maximum rate of 8 mm min(-1) (∼0.03 mm min(-1 ) μm(-2) ). Somatic sodium extrusion was accelerated at higher temperature and blocked by ouabain, emphasizing its dependence on NKA. Moreover, it was slowed down during inhibition of glycolysis by sodium fluoride (NaF). Local glutamate application to dendrites revealed a 10-fold higher apparent dendritic sodium extrusion rate compared to somata. Recovery was almost unaltered by increased temperature, ouabain or NaF. We found that sodium diffused along primary dendrites with a diffusion coefficient of ∼330 μm²/s. During global glutamate application, impeding substantial net diffusion, apparent dendritic extrusion rates were reduced to somatic rates and also affected by NaF. Numerical simulations confirmed the essential role of NKA for the recovery of somatic, but not dendritic sodium loads. Our data show that sodium export upon global sodium increases is largely mediated by NKA and depends on an intact energy metabolism. For recovery from local dendritic sodium increases, diffusion dominates over extrusion, operating efficiently even during short periods of energy deprivation. Although sodium will eventually be extruded by the NKA, its diffusion-based fast dissemination to non-stimulated regions might reduce local energy requirements.
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Affiliation(s)
- Miguel A Mondragão
- Institute of Neurobiology, Faculty of Mathematics and Natural Sciences, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Hartmut Schmidt
- Carl-Ludwig-Institute for Physiology, Medical Faculty, University of Leipzig, Leipzig, Germany
| | - Christian Kleinhans
- Institute of Neurobiology, Faculty of Mathematics and Natural Sciences, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Julia Langer
- Institute of Neurobiology, Faculty of Mathematics and Natural Sciences, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Karl W Kafitz
- Institute of Neurobiology, Faculty of Mathematics and Natural Sciences, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Christine R Rose
- Institute of Neurobiology, Faculty of Mathematics and Natural Sciences, Heinrich Heine University Düsseldorf, Düsseldorf, Germany.
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