1
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Calbiague-Garcia V, Chen Y, Cádiz B, Tapia F, Paquet-Durand F, Schmachtenberg O. Extracellular lactate as an alternative energy source for retinal bipolar cells. J Biol Chem 2024; 300:106794. [PMID: 38403245 PMCID: PMC10966802 DOI: 10.1016/j.jbc.2024.106794] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Revised: 02/11/2024] [Accepted: 02/16/2024] [Indexed: 02/27/2024] Open
Abstract
Retinal bipolar and amacrine cells receive visual information from photoreceptors and participate in the first steps of image processing in the retina. Several studies have suggested the operation of aerobic glycolysis and a lactate shuttle system in the retina due to the high production of this metabolite under aerobic conditions. However, whether bipolar cells form part of this metabolic circuit remains unclear. Here, we show that the monocarboxylate transporter 2 is expressed and functional in inner retinal neurons. Additionally, we used genetically encoded FRET nanosensors to demonstrate the ability of inner retinal neurons to consume extracellular lactate as an alternative to glucose. In rod bipolar cells, lactate consumption allowed cells to maintain the homeostasis of ions and electrical responses. We also found that lactate synthesis and transporter inhibition caused functional alterations and an increased rate of cell death. Overall, our data shed light on a notable but still poorly understood aspect of retinal metabolism.
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Affiliation(s)
- Victor Calbiague-Garcia
- PhD Program in Neuroscience, Universidad de Valparaíso, Valparaíso, Chile; CINV, Instituto de Biología, Universidad de Valparaíso, Valparaíso, Chile.
| | - Yiyi Chen
- Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany
| | - Bárbara Cádiz
- CINV, Instituto de Biología, Universidad de Valparaíso, Valparaíso, Chile
| | - Felipe Tapia
- CINV, Instituto de Biología, Universidad de Valparaíso, Valparaíso, Chile
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2
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Bøgh N, Sørensen CB, Alstrup AKO, Hansen ESS, Andersen OM, Laustsen C. Mice and minipigs with compromised expression of the Alzheimer's disease gene SORL1 show cerebral metabolic disturbances on hyperpolarized [1- 13C]pyruvate and sodium MRI. Brain Commun 2024; 6:fcae114. [PMID: 38650831 PMCID: PMC11034025 DOI: 10.1093/braincomms/fcae114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Revised: 01/24/2024] [Accepted: 03/29/2024] [Indexed: 04/25/2024] Open
Abstract
The sortilin-related receptor 1 (SORL1) gene, encoding the cellular endosomal sorting-related receptor with A-type repeats (SORLA), is now established as a causal gene for Alzheimer's disease. As the latest addition to the list of causal genes, the pathophysiological effects and biomarker potential of SORL1 variants remain relatively undiscovered. Metabolic dysfunction is, however, well described in patients with Alzheimer's disease and is used as an imaging biomarker in clinical diagnosis settings. To understand the metabolic consequences of loss-of-function SORL1 mutations, we applied two metabolic MRI technologies, sodium (23Na) MRI and MRI with hyperpolarized [1-13C]pyruvate, in minipigs and mice with compromised expression of SORL1. At the age analysed here, both animal models display no conventional imaging evidence of neurodegeneration but show biochemical signs of elevated amyloid production, thus representing the early preclinical disease. With hyperpolarized MRI, the exchange from [1-13C]pyruvate to [1-13C]lactate and 13C-bicarbonate was decreased by 32 and 23%, respectively, in the cerebrum of SORL1-haploinsufficient minipigs. A robust 11% decrease in the sodium content was observed with 23Na-MRI in the same minipigs. Comparably, the brain sodium concentration gradually decreased from control to SORL1 haploinsufficient (-11%) to SORL1 knockout mice (-23%), suggesting a gene dose dependence in the metabolic dysfunction. The present study highlights that metabolic MRI technologies are sensitive to the functional, metabolic consequences of Alzheimer's disease and Alzheimer's disease-linked genotypes. Further, the study suggests a potential avenue of research into the mechanisms of metabolic alterations by SORL1 mutations and their potential role in neurodegeneration.
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Affiliation(s)
- Nikolaj Bøgh
- Department of Clinical Medicine, The MR Research Centre, Aarhus University, 8200 Aarhus, Denmark
- A&E, Gødstrup Hospital, 7400 Herning, Denmark
| | | | - Aage K O Alstrup
- Department of Clinical Medicine, Aarhus University, 8200 Aarhus, Denmark
- Department of Nuclear Medicine and PET-Centre, Aarhus University Hospital, 8200 Aarhus, Denmark
| | - Esben S S Hansen
- Department of Clinical Medicine, The MR Research Centre, Aarhus University, 8200 Aarhus, Denmark
| | - Olav M Andersen
- Department of Biomedicine, Aarhus University, 8200 Aarhus, Denmark
| | - Christoffer Laustsen
- Department of Clinical Medicine, The MR Research Centre, Aarhus University, 8200 Aarhus, Denmark
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3
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Dreier JP, Lemale CL, Horst V, Major S, Kola V, Schoknecht K, Scheel M, Hartings JA, Vajkoczy P, Wolf S, Woitzik J, Hecht N. Similarities in the Electrographic Patterns of Delayed Cerebral Infarction and Brain Death After Aneurysmal and Traumatic Subarachnoid Hemorrhage. Transl Stroke Res 2024:10.1007/s12975-024-01237-w. [PMID: 38396252 DOI: 10.1007/s12975-024-01237-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2024] [Revised: 02/11/2024] [Accepted: 02/14/2024] [Indexed: 02/25/2024]
Abstract
While subarachnoid hemorrhage is the second most common hemorrhagic stroke in epidemiologic studies, the recent DISCHARGE-1 trial has shown that in reality, three-quarters of focal brain damage after subarachnoid hemorrhage is ischemic. Two-fifths of these ischemic infarctions occur early and three-fifths are delayed. The vast majority are cortical infarcts whose pathomorphology corresponds to anemic infarcts. Therefore, we propose in this review that subarachnoid hemorrhage as an ischemic-hemorrhagic stroke is rather a third, separate entity in addition to purely ischemic or hemorrhagic strokes. Cumulative focal brain damage, determined by neuroimaging after the first 2 weeks, is the strongest known predictor of patient outcome half a year after the initial hemorrhage. Because of the unique ability to implant neuromonitoring probes at the brain surface before stroke onset and to perform longitudinal MRI scans before and after stroke, delayed cerebral ischemia is currently the stroke variant in humans whose pathophysiological details are by far the best characterized. Optoelectrodes located directly over newly developing delayed infarcts have shown that, as mechanistic correlates of infarct development, spreading depolarizations trigger (1) spreading ischemia, (2) severe hypoxia, (3) persistent activity depression, and (4) transition from clustered spreading depolarizations to a negative ultraslow potential. Furthermore, traumatic brain injury and subarachnoid hemorrhage are the second and third most common etiologies of brain death during continued systemic circulation. Here, we use examples to illustrate that although the pathophysiological cascades associated with brain death are global, they closely resemble the local cascades associated with the development of delayed cerebral infarcts.
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Affiliation(s)
- Jens P Dreier
- Center for Stroke Research Berlin, Campus Charité Mitte, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Charitéplatz 1, 10117, Berlin, Germany.
- Department of Experimental Neurology, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.
- Department of Neurology, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.
- Bernstein Center for Computational Neuroscience Berlin, Berlin, Germany.
- Einstein Center for Neurosciences Berlin, Berlin, Germany.
| | - Coline L Lemale
- Center for Stroke Research Berlin, Campus Charité Mitte, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Charitéplatz 1, 10117, Berlin, Germany
- Department of Experimental Neurology, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Viktor Horst
- Center for Stroke Research Berlin, Campus Charité Mitte, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Charitéplatz 1, 10117, Berlin, Germany
- Institute of Neuropathology, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Sebastian Major
- Center for Stroke Research Berlin, Campus Charité Mitte, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Charitéplatz 1, 10117, Berlin, Germany
- Department of Experimental Neurology, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
- Department of Neurology, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Vasilis Kola
- Center for Stroke Research Berlin, Campus Charité Mitte, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Charitéplatz 1, 10117, Berlin, Germany
| | - Karl Schoknecht
- Medical Faculty, Carl Ludwig Institute for Physiology, University of Leipzig, Leipzig, Germany
| | - Michael Scheel
- Department of Neuroradiology, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Jed A Hartings
- Department of Neurosurgery, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Peter Vajkoczy
- Department of Neurosurgery, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Stefan Wolf
- Department of Neurosurgery, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Johannes Woitzik
- Department of Neurosurgery, Evangelisches Krankenhaus Oldenburg, University of Oldenburg, Oldenburg, Germany
| | - Nils Hecht
- Department of Neurosurgery, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
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4
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Khananshvili D. Neuronal and astrocyte NCX isoform/splice variants: How do they participate in Na + and Ca 2+ signalling? Cell Calcium 2023; 116:102818. [PMID: 37918135 DOI: 10.1016/j.ceca.2023.102818] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Revised: 10/20/2023] [Accepted: 10/22/2023] [Indexed: 11/04/2023]
Abstract
NCX1, NCX2, and NCX3 gene isoforms and their splice variants are characteristically expressed in different regions of the brain. The tissue-specific splice variants of NCX1-3 isoforms show specific expression profiles in neurons and astrocytes, whereas the relevant NCX isoform/splice variants exhibit diverse allosteric modes of Na+- and Ca2+-dependent regulation. In general, overexpression of NCX1-3 genes leads to neuroprotective effects, whereas their ablation gains the opposite results. At this end, the partial contributions of NCX isoform/splice variants to neuroprotective effects remain unresolved. The glutamate-dependent Na+ entry generates Na+ transients (in response to neuronal cell activities), whereas the Na+-driven Ca2+ entry (through the reverse NCX mode) raises Ca2+ transients. This special mode of signal coupling translates Na+ transients into the Ca2+ signals while being a part of synaptic neurotransmission. This mechanism is of general interest since disease-related conditions (ischemia, metabolic stress, and stroke among many others) trigger Na+ and Ca2+ overload with deadly outcomes of downstream apoptosis and excitotoxicity. The recently discovered mechanisms of NCX allosteric regulation indicate that some NCX variants might play a critical role in the dynamic coupling of Na+-driven Ca2+ entry. In contrast, the others are less important or even could be dangerous under altered conditions (e.g., metabolic stress). This working hypothesis can be tested by applying advanced experimental approaches and highly focused computational simulations. This may allow the development of structure-based blockers/activators that can selectively modulate predefined NCX variants to lessen the life-threatening outcomes of excitotoxicity, ischemia, apoptosis, metabolic deprivation, brain injury, and stroke.
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Affiliation(s)
- Daniel Khananshvili
- Department of Physiology and Pharmacology, Faculty of Medicine, Tel-Aviv University, Tel Aviv 69978, Israel.
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5
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Brazhe A, Verisokin A, Verveyko D, Postnov D. Astrocytes: new evidence, new models, new roles. Biophys Rev 2023; 15:1303-1333. [PMID: 37975000 PMCID: PMC10643736 DOI: 10.1007/s12551-023-01145-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Accepted: 09/08/2023] [Indexed: 11/19/2023] Open
Abstract
Astrocytes have been in the limelight of active research for about 3 decades now. Over this period, ideas about their function and role in the nervous system have evolved from simple assistance in energy supply and homeostasis maintenance to a complex informational and metabolic hub that integrates data on local neuronal activity, sensory and arousal context, and orchestrates many crucial processes in the brain. Rapid progress in experimental techniques and data analysis produces a growing body of data, which can be used as a foundation for formulation of new hypotheses, building new refined mathematical models, and ultimately should lead to a new level of understanding of the contribution of astrocytes to the cognitive tasks performed by the brain. Here, we highlight recent progress in astrocyte research, which we believe expands our understanding of how low-level signaling at a cellular level builds up to processes at the level of the whole brain and animal behavior. We start our review with revisiting data on the role of noradrenaline-mediated astrocytic signaling in locomotion, arousal, sensory integration, memory, and sleep. We then briefly review astrocyte contribution to the regulation of cerebral blood flow regulation, which is followed by a discussion of biophysical mechanisms underlying astrocyte effects on different brain processes. The experimental section is closed by an overview of recent experimental techniques available for modulation and visualization of astrocyte dynamics. We then evaluate how the new data can be potentially incorporated into the new mathematical models or where and how it already has been done. Finally, we discuss an interesting prospect that astrocytes may be key players in important processes such as the switching between sleep and wakefulness and the removal of toxic metabolites from the brain milieu.
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Affiliation(s)
- Alexey Brazhe
- Department of Biophysics, Biological Faculty, Lomonosov Moscow State University, Leninskie Gory, 1/24, Moscow, 119234 Russia
- Department of Molecular Neurobiology, Institute of Bioorganic Chemistry RAS, GSP-7, Miklukho-Maklay Str., 16/10, Moscow, 117997 Russia
| | - Andrey Verisokin
- Department of Theoretical Physics, Kursk State University, Radishcheva st., 33, Kursk, 305000 Russia
| | - Darya Verveyko
- Department of Theoretical Physics, Kursk State University, Radishcheva st., 33, Kursk, 305000 Russia
| | - Dmitry Postnov
- Department of Optics and Biophotonics, Saratov State University, Astrakhanskaya st., 83, Saratov, 410012 Russia
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6
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Costa RT, Santos MB, Alberto-Silva C, Carrettiero DC, Ribeiro CAJ. Methylmalonic Acid Impairs Cell Respiration and Glutamate Uptake in C6 Rat Glioma Cells: Implications for Methylmalonic Acidemia. Cell Mol Neurobiol 2023; 43:1163-1180. [PMID: 35674974 DOI: 10.1007/s10571-022-01236-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Accepted: 05/20/2022] [Indexed: 11/28/2022]
Abstract
Methylmalonic acidemia is an organic acidemia caused by deficient activity of L-methylmalonyl-CoA mutase or its cofactor cyanocobalamin and it is biochemically characterized by an accumulation of methylmalonic acid (MMA) in tissue and body fluids of patients. The main clinical manifestations of this disease are neurological and observable symptoms during metabolic decompensation are encephalopathy, cerebral atrophy, coma, and seizures, which commonly appear in newborns. This study aimed to investigate the toxic effects of MMA in a glial cell line presenting astrocytic features. Astroglial C6 cells were exposed to MMA (0.1-10 mM) for 24 or 48 h and cell metabolic viability, glucose consumption, and oxygen consumption rate, as well as glutamate uptake and ATP content were analyzed. The possible preventive effects of bezafibrate were also evaluated. MMA significantly reduced cell metabolic viability after 48-h period and increased glucose consumption during the same period of incubation. Regarding the energy homeostasis, MMA significantly reduced respiratory parameters of cells after 48-h exposure, indicating that cell metabolism is compromised at resting and reserve capacity state, which might influence the cell capacity to meet energetic demands. Glutamate uptake and ATP content were also compromised after exposure to MMA, which can be influenced energy metabolism impairment, affecting the functionality of the astroglial cells. Our findings suggest that these effects could be involved in the pathophysiology of neurological dysfunction of this disease. Methylmalonic acid compromises mitochondrial functioning leading to reduced ATP production and reduces glutamate uptake by C6 astroglial cells.
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Affiliation(s)
- Renata T Costa
- Centro de Ciências Naturais E Humanas (CCNH), UFABC - Universidade Federal do ABC, Alameda da Universidade, s/n, São Bernardo do Campo, SP, CEP 09606-045, Brazil
| | - Marcella B Santos
- Centro de Ciências Naturais E Humanas (CCNH), UFABC - Universidade Federal do ABC, Alameda da Universidade, s/n, São Bernardo do Campo, SP, CEP 09606-045, Brazil
| | - Carlos Alberto-Silva
- Centro de Ciências Naturais E Humanas (CCNH), UFABC - Universidade Federal do ABC, Alameda da Universidade, s/n, São Bernardo do Campo, SP, CEP 09606-045, Brazil
| | - Daniel C Carrettiero
- Centro de Ciências Naturais E Humanas (CCNH), UFABC - Universidade Federal do ABC, Alameda da Universidade, s/n, São Bernardo do Campo, SP, CEP 09606-045, Brazil
| | - César A J Ribeiro
- Centro de Ciências Naturais E Humanas (CCNH), UFABC - Universidade Federal do ABC, Alameda da Universidade, s/n, São Bernardo do Campo, SP, CEP 09606-045, Brazil.
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7
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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] [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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8
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Azilinon M, Makhalova J, Zaaraoui W, Medina Villalon S, Viout P, Roussel T, El Mendili MM, Ridley B, Ranjeva J, Bartolomei F, Jirsa V, Guye M. Combining sodium MRI, proton MR spectroscopic imaging, and intracerebral EEG in epilepsy. Hum Brain Mapp 2022; 44:825-840. [PMID: 36217746 PMCID: PMC9842896 DOI: 10.1002/hbm.26102] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Revised: 09/12/2022] [Accepted: 09/17/2022] [Indexed: 01/25/2023] Open
Abstract
Whole brain ionic and metabolic imaging has potential as a powerful tool for the characterization of brain diseases. We combined sodium MRI (23 Na MRI) and 1 H-MR Spectroscopic Imaging (1 H-MRSI), assessing changes within epileptogenic networks in comparison with electrophysiologically normal networks as defined by stereotactic EEG (SEEG) recordings analysis. We applied a multi-echo density adapted 3D projection reconstruction pulse sequence at 7 T (23 Na-MRI) and a 3D echo-planar spectroscopic imaging sequence at 3 T (1 H-MRSI) in 19 patients suffering from drug-resistant focal epilepsy who underwent presurgical SEEG. We investigated 23 Na MRI parameters including total sodium concentration (TSC) and the sodium signal fraction associated with the short component of T2 * decay (f), alongside the level of metabolites N-acetyl aspartate (NAA), choline compounds (Cho), and total creatine (tCr). All measures were extracted from spherical regions of interest (ROIs) centered between two adjacent SEEG electrode contacts and z-scored against the same ROI in controls. Group comparison showed a significant increase in f only in the epileptogenic zone (EZ) compared to controls and compared to patients' propagation zone (PZ) and non-involved zone (NIZ). TSC was significantly increased in all patients' regions compared to controls. Conversely, NAA levels were significantly lower in patients compared to controls, and lower in the EZ compared to PZ and NIZ. Multiple regression analyzing the relationship between sodium and metabolites levels revealed significant relations in PZ and in NIZ but not in EZ. Our results are in agreement with the energetic failure hypothesis in epileptic regions associated with widespread tissue reorganization.
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Affiliation(s)
- Mikhael Azilinon
- Aix Marseille Univ, CNRS, CRMBMMarseilleFrance,Aix Marseille Univ, INSERM, INS, Inst Neurosci SystMarseilleFrance,APHM, Timone Hospital, CEMEREMMarseilleFrance
| | - Julia Makhalova
- APHM, Timone Hospital, CEMEREMMarseilleFrance,Epileptology DepartmentAPHM, Timone HospitalMarseilleFrance
| | - Wafaa Zaaraoui
- Aix Marseille Univ, CNRS, CRMBMMarseilleFrance,APHM, Timone Hospital, CEMEREMMarseilleFrance
| | - Samuel Medina Villalon
- Aix Marseille Univ, INSERM, INS, Inst Neurosci SystMarseilleFrance,Epileptology DepartmentAPHM, Timone HospitalMarseilleFrance
| | - Patrick Viout
- Aix Marseille Univ, CNRS, CRMBMMarseilleFrance,APHM, Timone Hospital, CEMEREMMarseilleFrance
| | - Tangi Roussel
- Aix Marseille Univ, CNRS, CRMBMMarseilleFrance,APHM, Timone Hospital, CEMEREMMarseilleFrance
| | - Mohamed M. El Mendili
- Aix Marseille Univ, CNRS, CRMBMMarseilleFrance,APHM, Timone Hospital, CEMEREMMarseilleFrance
| | - Ben Ridley
- IRCCS Istituto delle Scienze Neurologiche di BolognaBolognaItaly
| | - Jean‐Philippe Ranjeva
- Aix Marseille Univ, CNRS, CRMBMMarseilleFrance,APHM, Timone Hospital, CEMEREMMarseilleFrance
| | - Fabrice Bartolomei
- Aix Marseille Univ, INSERM, INS, Inst Neurosci SystMarseilleFrance,Epileptology DepartmentAPHM, Timone HospitalMarseilleFrance
| | - Viktor Jirsa
- Aix Marseille Univ, INSERM, INS, Inst Neurosci SystMarseilleFrance
| | - Maxime Guye
- Aix Marseille Univ, CNRS, CRMBMMarseilleFrance,APHM, Timone Hospital, CEMEREMMarseilleFrance
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9
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Rodrigues T, Piccirillo S, Magi S, Preziuso A, Dos Santos Ramos V, Serfilippi T, Orciani M, Maciel Palacio Alvarez M, Luis Dos Santos Tersariol I, Amoroso S, Lariccia V. Control of Ca 2+ and metabolic homeostasis by the Na +/Ca 2+ exchangers (NCXs) in health and disease. Biochem Pharmacol 2022; 203:115163. [PMID: 35803319 DOI: 10.1016/j.bcp.2022.115163] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Revised: 06/30/2022] [Accepted: 07/01/2022] [Indexed: 11/16/2022]
Abstract
Spatial and temporal control of calcium (Ca2+) levels is essential for the background rhythms and responses of living cells to environmental stimuli. Whatever other regulators a given cellular activity may have, localized and wider scale Ca2+ events (sparks, transients, and waves) are hierarchical determinants of fundamental processes such as cell contraction, excitability, growth, metabolism and survival. Different cell types express specific channels, pumps and exchangers to efficiently generate and adapt Ca2+ patterns to cell requirements. The Na+/Ca2+ exchangers (NCXs) in particular contribute to Ca2+ homeostasis by buffering intracellular Ca2+ loads according to the electrochemical gradients of substrate ions - i.e., Ca2+ and sodium (Na+) - and under a dynamic control of redundant regulatory processes. An interesting feature of NCX emerges from the strict relationship that connects transporter activity with cell metabolism: on the one hand NCX operates under constant control of ATP-dependent regulatory processes, on the other hand the ion fluxes generated through NCX provide mechanistic support for the Na+-driven uptake of glutamate and Ca2+ influx to fuel mitochondrial respiration. Proof of concept evidence highlights therapeutic potential of preserving a timed and balanced NCX activity in a growing rate of diseases (including excitability, neurodegenerative, and proliferative disorders) because of an improved ability of stressed cells to safely maintain ion gradients and mitochondrial bioenergetics. Here, we will summarize and review recent works that have focused on the pathophysiological roles of NCXs in balancing the two-way relationship between Ca2+ signals and metabolism.
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Affiliation(s)
- Tiago Rodrigues
- Center for Natural and Human Sciences (CCNH), Federal University of ABC (UFABC), Santo André, SP, Brazil.
| | - Silvia Piccirillo
- Department of Biomedical Sciences and Public Health, School of Medicine, University "Politecnica delle Marche", Ancona, Italy.
| | - Simona Magi
- Department of Biomedical Sciences and Public Health, School of Medicine, University "Politecnica delle Marche", Ancona, Italy.
| | - Alessandra Preziuso
- Department of Biomedical Sciences and Public Health, School of Medicine, University "Politecnica delle Marche", Ancona, Italy.
| | - Vyctória Dos Santos Ramos
- Interdisciplinary Center for Biochemistry Investigation (CIIB), University of Mogi das Cruzes (UMC), Mogi das Cruzes, SP, Brazil
| | - Tiziano Serfilippi
- Department of Biomedical Sciences and Public Health, School of Medicine, University "Politecnica delle Marche", Ancona, Italy.
| | - Monia Orciani
- Department of Clinical and Molecular Sciences, Histology, University "Politecnica delle Marche", Ancona, Italy.
| | - Marcela Maciel Palacio Alvarez
- Department of Biochemistry, São Paulo School of Medicine, Federal University of São Paulo (Unifesp) São Paulo, SP, Brazil
| | | | - Salvatore Amoroso
- Department of Biomedical Sciences and Public Health, School of Medicine, University "Politecnica delle Marche", Ancona, Italy.
| | - Vincenzo Lariccia
- Department of Biomedical Sciences and Public Health, School of Medicine, University "Politecnica delle Marche", Ancona, Italy.
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10
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Shen Z, Xiang M, Chen C, Ding F, Wang Y, Shang C, Xin L, Zhang Y, Cui X. Glutamate excitotoxicity: Potential therapeutic target for ischemic stroke. Biomed Pharmacother 2022; 151:113125. [PMID: 35609367 DOI: 10.1016/j.biopha.2022.113125] [Citation(s) in RCA: 44] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Revised: 05/01/2022] [Accepted: 05/13/2022] [Indexed: 11/29/2022] Open
Abstract
Glutamate-mediated excitotoxicity is an important mechanism leading to post ischemic stroke damage. After acute stroke, the sudden reduction in cerebral blood flow is most initially followed by ion transport protein dysfunction and disruption of ion homeostasis, which in turn leads to impaired glutamate release, reuptake, and excessive N-methyl-D-aspartate receptor (NMDAR) activation, promoting neuronal death. Despite extensive evidence from preclinical studies suggesting that excessive NMDAR stimulation during ischemic stroke is a central step in post-stroke damage, NMDAR blockers have failed to translate into clinical stroke treatment. Current treatment options for stroke are very limited, and there is therefore a great need to develop new targets for neuroprotective therapeutic agents in ischemic stroke to extend the therapeutic time window. In this review, we highlight recent findings on glutamate release, reuptake mechanisms, NMDAR and its downstream cellular signaling pathways in post-ischemic stroke damage, and review the pathological changes in each link to help develop viable new therapeutic targets. We then also summarize potential neuroprotective drugs and therapeutic approaches for these new targets in the treatment of ischemic stroke.
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Affiliation(s)
- Zihuan Shen
- Department of Cardiovascular, Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing 100053, China; Clinical Medical School, Beijing University of Traditional Chinese Medicine, Beijing 100029, China
| | - Mi Xiang
- Department of Cardiovascular, Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing 100053, China
| | - Chen Chen
- Department of Cardiovascular, Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing 100053, China
| | - Fan Ding
- Department of Cardiovascular, Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing 100053, China; Clinical Medical School, Beijing University of Traditional Chinese Medicine, Beijing 100029, China
| | - Yuling Wang
- Department of Cardiovascular, Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing 100053, China; Clinical Medical School, Beijing University of Traditional Chinese Medicine, Beijing 100029, China
| | - Chang Shang
- Department of Cardiovascular, Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing 100053, China; Clinical Medical School, Beijing University of Traditional Chinese Medicine, Beijing 100029, China
| | - Laiyun Xin
- Department of Cardiovascular, Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing 100053, China
| | - Yang Zhang
- Department of Cardiovascular, Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing 100053, China.
| | - Xiangning Cui
- Department of Cardiovascular, Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing 100053, China.
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11
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Huo Y, Sawant A, Tan Y, Mahdi AH, Li T, Ma H, Bhatt V, Yan R, Coleman J, Dreyfus CF, Guo JY, Mouradian MM, White E, Xia B. Tumor suppressor PALB2 maintains redox and mitochondrial homeostasis in the brain and cooperates with ATG7/autophagy to suppress neurodegeneration. PLoS Genet 2022; 18:e1010138. [PMID: 35404932 PMCID: PMC9022806 DOI: 10.1371/journal.pgen.1010138] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2021] [Revised: 04/21/2022] [Accepted: 03/09/2022] [Indexed: 01/22/2023] Open
Abstract
The PALB2 tumor suppressor plays key roles in DNA repair and has been implicated in redox homeostasis. Autophagy maintains mitochondrial quality, mitigates oxidative stress and suppresses neurodegeneration. Here we show that Palb2 deletion in the mouse brain leads to mild motor deficits and that co-deletion of Palb2 with the essential autophagy gene Atg7 accelerates and exacerbates neurodegeneration induced by ATG7 loss. Palb2 deletion leads to elevated DNA damage, oxidative stress and mitochondrial markers, especially in Purkinje cells, and co-deletion of Palb2 and Atg7 results in accelerated Purkinje cell loss. Further analyses suggest that the accelerated Purkinje cell loss and severe neurodegeneration in the double deletion mice are due to excessive oxidative stress and mitochondrial dysfunction, rather than DNA damage, and partially dependent on p53 activity. Our studies uncover a role of PALB2 in mitochondrial homeostasis and a cooperation between PALB2 and ATG7/autophagy in maintaining redox and mitochondrial homeostasis essential for neuronal survival.
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Affiliation(s)
- Yanying Huo
- Rutgers Cancer Institute of New Jersey, New Brunswick, New Jersey, United States of America
- Department of Radiation Oncology, Rutgers Robert Wood Johnson Medical School, New Brunswick, New Jersey, United States of America
| | - Akshada Sawant
- Rutgers Cancer Institute of New Jersey, New Brunswick, New Jersey, United States of America
- Department of Molecular Biology and Biochemistry, Rutgers, The State University of New Jersey, Piscataway, New Jersey, United States of America
| | - Yongmei Tan
- Stomatological Hospital of Guangzhou Medical University, Guangzhou, P.R. China
| | - Amar H Mahdi
- Rutgers Cancer Institute of New Jersey, New Brunswick, New Jersey, United States of America
- Department of Radiation Oncology, Rutgers Robert Wood Johnson Medical School, New Brunswick, New Jersey, United States of America
| | - Tao Li
- Rutgers Cancer Institute of New Jersey, New Brunswick, New Jersey, United States of America
- Department of Radiation Oncology, Rutgers Robert Wood Johnson Medical School, New Brunswick, New Jersey, United States of America
| | - Hui Ma
- Rutgers Cancer Institute of New Jersey, New Brunswick, New Jersey, United States of America
- Department of Radiation Oncology, Rutgers Robert Wood Johnson Medical School, New Brunswick, New Jersey, United States of America
| | - Vrushank Bhatt
- Rutgers Cancer Institute of New Jersey, New Brunswick, New Jersey, United States of America
- Department of Medicine, Rutgers Robert Wood Johnson Medical School, New Brunswick, New Jersey, United States of America
| | - Run Yan
- Department of Neurology, Rutgers Robert Wood Johnson Medical School, New Brunswick, New Jersey, United States of America
- RWJMS Institute for Neurological Therapeutics, Rutgers Robert Wood Johnson Medical School, New Brunswick, New Jersey, United States of America
| | - Jake Coleman
- Rutgers Cancer Institute of New Jersey, New Brunswick, New Jersey, United States of America
- Department of Neuroscience and Cell Biology, Rutgers Robert Wood Johnson Medical School, New Brunswick, New Jersey, United States of America
| | - Cheryl F Dreyfus
- Rutgers School of Environmental and Biological Sciences, New Brunswick, New Jersey, United States of America
| | - Jessie Yanxiang Guo
- Rutgers Cancer Institute of New Jersey, New Brunswick, New Jersey, United States of America
- Department of Medicine, Rutgers Robert Wood Johnson Medical School, New Brunswick, New Jersey, United States of America
- Department of Chemical Biology, Rutgers Ernest Mario School of Pharmacy, Piscataway, New Jersey, United States of America
| | - M. Maral Mouradian
- Department of Neurology, Rutgers Robert Wood Johnson Medical School, New Brunswick, New Jersey, United States of America
- RWJMS Institute for Neurological Therapeutics, Rutgers Robert Wood Johnson Medical School, New Brunswick, New Jersey, United States of America
| | - Eileen White
- Rutgers Cancer Institute of New Jersey, New Brunswick, New Jersey, United States of America
- Department of Molecular Biology and Biochemistry, Rutgers, The State University of New Jersey, Piscataway, New Jersey, United States of America
| | - Bing Xia
- Rutgers Cancer Institute of New Jersey, New Brunswick, New Jersey, United States of America
- Department of Radiation Oncology, Rutgers Robert Wood Johnson Medical School, New Brunswick, New Jersey, United States of America
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12
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Lemale CL, Lückl J, Horst V, Reiffurth C, Major S, Hecht N, Woitzik J, Dreier JP. Migraine Aura, Transient Ischemic Attacks, Stroke, and Dying of the Brain Share the Same Key Pathophysiological Process in Neurons Driven by Gibbs–Donnan Forces, Namely Spreading Depolarization. Front Cell Neurosci 2022; 16:837650. [PMID: 35237133 PMCID: PMC8884062 DOI: 10.3389/fncel.2022.837650] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Accepted: 01/19/2022] [Indexed: 12/15/2022] Open
Abstract
Neuronal cytotoxic edema is the morphological correlate of the near-complete neuronal battery breakdown called spreading depolarization, or conversely, spreading depolarization is the electrophysiological correlate of the initial, still reversible phase of neuronal cytotoxic edema. Cytotoxic edema and spreading depolarization are thus different modalities of the same process, which represents a metastable universal reference state in the gray matter of the brain close to Gibbs–Donnan equilibrium. Different but merging sections of the spreading-depolarization continuum from short duration waves to intermediate duration waves to terminal waves occur in a plethora of clinical conditions, including migraine aura, ischemic stroke, traumatic brain injury, aneurysmal subarachnoid hemorrhage (aSAH) and delayed cerebral ischemia (DCI), spontaneous intracerebral hemorrhage, subdural hematoma, development of brain death, and the dying process during cardio circulatory arrest. Thus, spreading depolarization represents a prime and simultaneously the most neglected pathophysiological process in acute neurology. Aristides Leão postulated as early as the 1940s that the pathophysiological process in neurons underlying migraine aura is of the same nature as the pathophysiological process in neurons that occurs in response to cerebral circulatory arrest, because he assumed that spreading depolarization occurs in both conditions. With this in mind, it is not surprising that patients with migraine with aura have about a twofold increased risk of stroke, as some spreading depolarizations leading to the patient percept of migraine aura could be caused by cerebral ischemia. However, it is in the nature of spreading depolarization that it can have different etiologies and not all spreading depolarizations arise because of ischemia. Spreading depolarization is observed as a negative direct current (DC) shift and associated with different changes in spontaneous brain activity in the alternating current (AC) band of the electrocorticogram. These are non-spreading depression and spreading activity depression and epileptiform activity. The same spreading depolarization wave may be associated with different activity changes in adjacent brain regions. Here, we review the basal mechanism underlying spreading depolarization and the associated activity changes. Using original recordings in animals and patients, we illustrate that the associated changes in spontaneous activity are by no means trivial, but pose unsolved mechanistic puzzles and require proper scientific analysis.
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Affiliation(s)
- Coline L. Lemale
- Center for Stroke Research Berlin, Berlin Institute of Health, Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany
- Department of Experimental Neurology, Berlin Institute of Health, Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Janos Lückl
- Center for Stroke Research Berlin, Berlin Institute of Health, Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany
- Department of Medical Physics and Informatics, University of Szeged, Szeged, Hungary
- Department of Neurology, University of Szeged, Szeged, Hungary
| | - Viktor Horst
- Center for Stroke Research Berlin, Berlin Institute of Health, Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Clemens Reiffurth
- Center for Stroke Research Berlin, Berlin Institute of Health, Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany
- Department of Experimental Neurology, Berlin Institute of Health, Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Sebastian Major
- Center for Stroke Research Berlin, Berlin Institute of Health, Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany
- Department of Experimental Neurology, Berlin Institute of Health, Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany
- Department of Neurology, Berlin Institute of Health, Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Nils Hecht
- Department of Neurosurgery, Berlin Institute of Health, Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Johannes Woitzik
- Department of Neurosurgery, Evangelisches Krankenhaus Oldenburg, University of Oldenburg, Oldenburg, Germany
| | - Jens P. Dreier
- Center for Stroke Research Berlin, Berlin Institute of Health, Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany
- Department of Experimental Neurology, Berlin Institute of Health, Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany
- Department of Neurology, Berlin Institute of Health, Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany
- Bernstein Center for Computational Neuroscience Berlin, Berlin, Germany
- Einstein Center for Neurosciences Berlin, Berlin, Germany
- *Correspondence: Jens P. Dreier,
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13
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Abstract
Although glucose classically serves as the main neuronal fuel source in the brain, Silva et al. demonstrate that ketones produced by local glial cells are critical for memory formation in starving flies. Here we discuss the implications of these findings for aging, neurodegeneration and the genetics of ketone metabolism.
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Affiliation(s)
| | - Sudipta Bar
- Buck Institute for Research on Aging, Novato, CA, USA
| | - Pankaj Kapahi
- Buck Institute for Research on Aging, Novato, CA, USA.
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14
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Piccialli I, Ciccone R, Secondo A, Boscia F, Tedeschi V, de Rosa V, Cepparulo P, Annunziato L, Pannaccione A. The Na +/Ca 2+ Exchanger 3 Is Functionally Coupled With the Na V1.6 Voltage-Gated Channel and Promotes an Endoplasmic Reticulum Ca 2+ Refilling in a Transgenic Model of Alzheimer's Disease. Front Pharmacol 2021; 12:775271. [PMID: 34955845 PMCID: PMC8692738 DOI: 10.3389/fphar.2021.775271] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Accepted: 11/22/2021] [Indexed: 01/15/2023] Open
Abstract
The remodelling of neuronal ionic homeostasis by altered channels and transporters is a critical feature of the Alzheimer's disease (AD) pathogenesis. Different reports converge on the concept that the Na+/Ca2+ exchanger (NCX), as one of the main regulators of Na+ and Ca2+ concentrations and signalling, could exert a neuroprotective role in AD. The activity of NCX has been found to be increased in AD brains, where it seemed to correlate with an increased neuronal survival. Moreover, the enhancement of the NCX3 currents (INCX) in primary neurons treated with the neurotoxic amyloid β 1-42 (Aβ1-42) oligomers prevented the endoplasmic reticulum (ER) stress and neuronal death. The present study has been designed to investigate any possible modulation of the INCX, the functional interaction between NCX and the NaV1.6 channel, and their impact on the Ca2+ homeostasis in a transgenic in vitro model of AD, the primary hippocampal neurons from the Tg2576 mouse, which overproduce the Aβ1-42 peptide. Electrophysiological studies, carried in the presence of siRNA and the isoform-selective NCX inhibitor KB-R7943, showed that the activity of a specific NCX isoform, NCX3, was upregulated in its reverse, Ca2+ influx mode of operation in the Tg2576 neurons. The enhanced NCX activity contributed, in turn, to increase the ER Ca2+ content, without affecting the cytosolic Ca2+ concentrations of the Tg2576 neurons. Interestingly, our experiments have also uncovered a functional coupling between NCX3 and the voltage-gated NaV1.6 channels. In particular, the increased NaV1.6 currents appeared to be responsible for the upregulation of the reverse mode of NCX3, since both TTX and the Streptomyces griseolus antibiotic anisomycin, by reducing the NaV1.6 currents, counteracted the increase of the INCX in the Tg2576 neurons. In agreement, our immunofluorescence analyses revealed that the NCX3/NaV1.6 co-expression was increased in the Tg2576 hippocampal neurons in comparison with the WT neurons. Collectively, these findings indicate that NCX3 might intervene in the Ca2+ remodelling occurring in the Tg2576 primary neurons thus emerging as a molecular target with a neuroprotective potential, and provide a new outcome of the NaV1.6 upregulation related to the modulation of the intracellular Ca2+ concentrations in AD neurons.
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Affiliation(s)
- Ilaria Piccialli
- Division of Pharmacology, Department of Neuroscience, Reproductive and Dentistry Sciences, School of Medicine, Federico II University of Naples, Naples, Italy
| | - Roselia Ciccone
- Division of Pharmacology, Department of Neuroscience, Reproductive and Dentistry Sciences, School of Medicine, Federico II University of Naples, Naples, Italy
| | - Agnese Secondo
- Division of Pharmacology, Department of Neuroscience, Reproductive and Dentistry Sciences, School of Medicine, Federico II University of Naples, Naples, Italy
| | - Francesca Boscia
- Division of Pharmacology, Department of Neuroscience, Reproductive and Dentistry Sciences, School of Medicine, Federico II University of Naples, Naples, Italy
| | - Valentina Tedeschi
- Division of Pharmacology, Department of Neuroscience, Reproductive and Dentistry Sciences, School of Medicine, Federico II University of Naples, Naples, Italy
| | - Valeria de Rosa
- Division of Pharmacology, Department of Neuroscience, Reproductive and Dentistry Sciences, School of Medicine, Federico II University of Naples, Naples, Italy
| | - Pasquale Cepparulo
- Division of Pharmacology, Department of Neuroscience, Reproductive and Dentistry Sciences, School of Medicine, Federico II University of Naples, Naples, Italy
| | | | - Anna Pannaccione
- Division of Pharmacology, Department of Neuroscience, Reproductive and Dentistry Sciences, School of Medicine, Federico II University of Naples, Naples, Italy
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15
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Shen XY, Gao ZK, Han Y, Yuan M, Guo YS, Bi X. Activation and Role of Astrocytes in Ischemic Stroke. Front Cell Neurosci 2021; 15:755955. [PMID: 34867201 PMCID: PMC8635513 DOI: 10.3389/fncel.2021.755955] [Citation(s) in RCA: 60] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Accepted: 10/22/2021] [Indexed: 12/21/2022] Open
Abstract
Ischemic stroke refers to the disorder of blood supply of local brain tissue caused by various reasons. It has high morbidity and mortality worldwide. Astrocytes are the most abundant glial cells in the central nervous system (CNS). They are responsible for the homeostasis, nutrition, and protection of the CNS and play an essential role in many nervous system diseases’ physiological and pathological processes. After stroke injury, astrocytes are activated and play a protective role through the heterogeneous and gradual changes of their gene expression, morphology, proliferation, and function, that is, reactive astrocytes. However, the position of reactive astrocytes has always been a controversial topic. Many studies have shown that reactive astrocytes are a double-edged sword with both beneficial and harmful effects. It is worth noting that their different spatial and temporal expression determines astrocytes’ various functions. Here, we comprehensively review the different roles and mechanisms of astrocytes after ischemic stroke. In addition, the intracellular mechanism of astrocyte activation has also been involved. More importantly, due to the complex cascade reaction and action mechanism after ischemic stroke, the role of astrocytes is still difficult to define. Still, there is no doubt that astrocytes are one of the critical factors mediating the deterioration or improvement of ischemic stroke.
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Affiliation(s)
- Xin-Ya Shen
- Graduate School of Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Zhen-Kun Gao
- Graduate School of Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Yu Han
- Department of Sport Rehabilitation, Shanghai University of Sport, Shanghai, China
| | - Mei Yuan
- Department of Sport Rehabilitation, Shanghai University of Sport, Shanghai, China
| | - Yi-Sha Guo
- Department of Sport Rehabilitation, Shanghai University of Sport, Shanghai, China
| | - Xia Bi
- Department of Rehabilitation Medicine, Shanghai University of Medicine and Health Sciences Affiliated Zhoupu Hospital, Shanghai, China
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16
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Maex R. Effect of extracellular volume on the energy stored in transmembrane concentration gradients. Phys Rev E 2021; 104:044409. [PMID: 34781519 DOI: 10.1103/physreve.104.044409] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Accepted: 09/30/2021] [Indexed: 11/07/2022]
Abstract
The amount of energy that can be retrieved from a concentration gradient across a membrane separating two compartments depends on the relative size of the compartments. Having a larger low-concentration compartment is in general beneficial. It is shown here analytically that the retrieved energy further increases when the high-concentration compartment shrinks during the mixing process, and a general formula is derived for the energy when the ratio of transported solvent to solute varies. These calculations are then applied to the interstitial compartment of the brain, which is rich in Na^{+} and Cl^{-} ions and poor in K^{+}. The reported shrinkage of this compartment, and swelling of the neurons, during oxygen deprivation is shown to enhance the energy recovered from NaCl entering the neurons. The slight loss of energy on the part of K^{+} can be compensated for by the uptake of K^{+} ions by glial cells. In conclusion, the present study proposes that the reported fluctuations in the size of the interstitial compartment of the brain (expansion during sleep and contraction during oxygen deprivation) optimize the amount of energy that neurons can store in, and retrieve from, their ionic concentration gradients.
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Affiliation(s)
- Reinoud Maex
- Biocomputation Research Group, University of Hertfordshire, Hatfield AL10 9AB, United Kingdom
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17
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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] [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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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] [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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Hossain MJ, Kendig MD, Wild BM, Issar T, Krishnan AV, Morris MJ, Arnold R. Evidence of Altered Peripheral Nerve Function in a Rodent Model of Diet-Induced Prediabetes. Biomedicines 2020; 8:biomedicines8090313. [PMID: 32872256 PMCID: PMC7555926 DOI: 10.3390/biomedicines8090313] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 08/26/2020] [Accepted: 08/26/2020] [Indexed: 12/12/2022] Open
Abstract
Peripheral neuropathy (PN) is a debilitating complication of diabetes that affects >50% of patients. Recent evidence suggests that obesity and metabolic disease, which often precede diabetes diagnosis, may influence PN onset and severity. We examined this in a translationally relevant model of prediabetes induced by a cafeteria (CAF) diet in Sprague–Dawley rats (n = 15 CAF versus n = 15 control). Neuropathy phenotyping included nerve conduction, tactile sensitivity, intraepidermal nerve fiber density (IENFD) and nerve excitability testing, an in vivo measure of ion channel function and membrane potential. Metabolic phenotyping included body composition, blood glucose and lipids, plasma hormones and inflammatory cytokines. After 13 weeks diet, CAF-fed rats demonstrated prediabetes with significantly elevated fasting blood glucose, insulin and impaired glucose tolerance as well as obesity and dyslipidemia. Nerve conduction, tactile sensitivity and IENFD did not differ; however, superexcitability was significantly increased in CAF-fed rats. Mathematical modeling demonstrated this was consistent with a reduction in sodium–potassium pump current. Moreover, superexcitability correlated positively with insulin resistance and adiposity, and negatively with fasting high-density lipoprotein cholesterol. In conclusion, prediabetic rats over-consuming processed, palatable foods demonstrated altered nerve function that preceded overt PN. This work provides a relevant model for pathophysiological investigation of diabetic complications.
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Affiliation(s)
- Md Jakir Hossain
- School of Medical Sciences, UNSW Sydney, Sydney, NSW 2052, Australia; (M.J.H.); (M.D.K.); (B.M.W.); (M.J.M.)
| | - Michael D. Kendig
- School of Medical Sciences, UNSW Sydney, Sydney, NSW 2052, Australia; (M.J.H.); (M.D.K.); (B.M.W.); (M.J.M.)
| | - Brandon M. Wild
- School of Medical Sciences, UNSW Sydney, Sydney, NSW 2052, Australia; (M.J.H.); (M.D.K.); (B.M.W.); (M.J.M.)
| | - Tushar Issar
- Prince of Wales Clinical School, UNSW Sydney, Sydney, NSW 2052, Australia; (T.I.); (A.V.K.)
| | - Arun V. Krishnan
- Prince of Wales Clinical School, UNSW Sydney, Sydney, NSW 2052, Australia; (T.I.); (A.V.K.)
| | - Margaret J. Morris
- School of Medical Sciences, UNSW Sydney, Sydney, NSW 2052, Australia; (M.J.H.); (M.D.K.); (B.M.W.); (M.J.M.)
| | - Ria Arnold
- School of Medical Sciences, UNSW Sydney, Sydney, NSW 2052, Australia; (M.J.H.); (M.D.K.); (B.M.W.); (M.J.M.)
- Correspondence: ; Tel.: +61-293858709
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20
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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] [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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21
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Flønes IH, Ricken G, Klotz S, Lang A, Ströbel T, Dölle C, Kovacs GG, Tzoulis C. Mitochondrial respiratory chain deficiency correlates with the severity of neuropathology in sporadic Creutzfeldt-Jakob disease. Acta Neuropathol Commun 2020; 8:50. [PMID: 32299489 PMCID: PMC7160955 DOI: 10.1186/s40478-020-00915-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2020] [Accepted: 03/13/2020] [Indexed: 01/30/2023] Open
Abstract
Mitochondrial dysfunction has been implicated in multiple neurodegenerative diseases but remains largely unexplored in Creutzfeldt-Jakob disease. Here, we characterize the mitochondrial respiratory chain at the individual neuron level in the MM1 and VV2 common molecular subtypes of sporadic Creutzfeldt-Jakob disease. Moreover, we investigate the associations between the mitochondrial respiratory chain and neuropathological markers of the disease.Brain tissue from individuals with sporadic Creutzfeldt-Jakob disease and age-matched controls were obtained from the brain collection of the Austrian Creutzfeldt-Jakob Surveillance. The mitochondrial respiratory chain was studied through a dichotomous approach of immunoreactivities in the temporal cortex and the hippocampal subregions of CA4 and CA3.We show that profound deficiency of all mitochondrial respiratory complexes (I-V) occurs in neurons of the severely affected temporal cortex of patients with Creutzfeldt-Jakob disease. This deficiency correlates strongly with the severity of neuropathological changes, including vacuolation of the neuropil, gliosis and disease associated prion protein load. Respiratory chain deficiency is less pronounced in hippocampal CA4 and CA3 regions compared to the temporal cortex. In both areas respiratory chain deficiency shows a predilection for the MM1 molecular subtype of Creutzfeldt-Jakob disease.Our findings indicate that aberrant mitochondrial respiration could be involved early in the pathogenesis of sporadic Creutzfeldt-Jakob disease and contributes to neuronal death, most likely via ATP depletion. Based on these results, we propose that the restricted MRI diffusion profile seen in the brain of patients with sporadic Creutzfeldt-Jakob disease might reflect cytotoxic changes due to neuronal respiratory chain failure and ATP loss.
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Affiliation(s)
- Irene H Flønes
- Neuro-SysMed, Department of Neurology, Haukeland University Hospital, 5021, Bergen, Norway
- Department of Clinical Medicine, University of Bergen, Pb 7804, 5020, Bergen, Norway
| | - Gerda Ricken
- Institute of Neurology, Medical University of Vienna, Vienna, Austria
| | - Sigrid Klotz
- Institute of Neurology, Medical University of Vienna, Vienna, Austria
| | - Alexandra Lang
- Institute of Neurology, Medical University of Vienna, Vienna, Austria
| | - Thomas Ströbel
- Institute of Neurology, Medical University of Vienna, Vienna, Austria
| | - Christian Dölle
- Neuro-SysMed, Department of Neurology, Haukeland University Hospital, 5021, Bergen, Norway
- Department of Clinical Medicine, University of Bergen, Pb 7804, 5020, Bergen, Norway
| | - Gabor G Kovacs
- Institute of Neurology, Medical University of Vienna, Vienna, Austria.
- Tanz Centre for Research in Neurodegenerative Disease, University of Toronto, Toronto, Ontario, Canada.
- Laboratory Medicine Program, University Health Network, Toronto, Canada.
| | - Charalampos Tzoulis
- Neuro-SysMed, Department of Neurology, Haukeland University Hospital, 5021, Bergen, Norway.
- Department of Clinical Medicine, University of Bergen, Pb 7804, 5020, Bergen, Norway.
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22
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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] [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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Lutz NW, Bernard M. A method for multiparametric statistical quantification of the heterogeneity of free Na + concentration by 19 F MR spectroscopy: Proof of principle in silico and in vitro. NMR IN BIOMEDICINE 2019; 32:e4117. [PMID: 31297903 DOI: 10.1002/nbm.4117] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2018] [Revised: 04/01/2019] [Accepted: 04/23/2019] [Indexed: 06/10/2023]
Abstract
Sodium(I) (Na+ ) is one of the most important cations in mammalian tissues. Since Na+ plays a key role in basic cell function, noninvasive methods for measuring intracellular concentrations of free sodium ions in biological tissue have been developed on the basis of 19 F NMR spectroscopy. However, intracellular Na+ levels are often not uniform throughout a tissue volume (or voxel) being measured. In such cases, [Na+ ] heterogeneity is not reflected in results obtained by the classical technique, and may even result in biased average values. For this reason, we have designed an approach for quantifying [Na+ ] heterogeneity. First, the 19 F MRS resonance from FCrown-1 serving as a "Na+ probe" is transformed into a [Na+ ] curve. Then the digital points of the resulting [Na+ ] profile are used to construct a histogram with specially developed algorithms. From each [Na+ ] histogram, at least eight quantitative parameters describing the underlying statistical [Na+ ] distribution were computed: weighted median, weighted mean, standard deviation, range, mode(s), kurtosis, skewness, and entropy. In addition to our new paradigm, we present a first validation based on (i) computer simulations and (ii) experimentally obtained 19 F MR spectra of model solutions. This basic proof of principle warrants future in vivo experiments, in particular because of its ability to provide quantitative information complementary to that made available by commonly used 23 Na MRI: (i) multiparametric statistical characterization of [Na+ ] distributions; (ii) total [Na+ ] heterogeneity analysis not intrinsically limited by the size of any MRI voxels; and (iii) analysis of unequivocally intracellular [Na+ ], as opposed to measurement of a combination of intra- and extracellular [Na+ ].
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Affiliation(s)
- Norbert W Lutz
- School of Medicine, CRMBM, Aix-Marseille University, Marseille, France
| | - Monique Bernard
- School of Medicine, CRMBM, Aix-Marseille University, Marseille, France
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24
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Lozano DC, Choe TE, Cepurna WO, Morrison JC, Johnson EC. Early Optic Nerve Head Glial Proliferation and Jak-Stat Pathway Activation in Chronic Experimental Glaucoma. Invest Ophthalmol Vis Sci 2019; 60:921-932. [PMID: 30835784 PMCID: PMC6402265 DOI: 10.1167/iovs.18-25700] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2018] [Accepted: 01/25/2019] [Indexed: 12/18/2022] Open
Abstract
PURPOSE We previously reported increased expression of cell proliferation and Jak-Stat pathway-related genes in chronic experimental glaucoma model optic nerve heads (ONH) with early, mild injury. Here, we confirm these observations by localizing, identifying, and quantifying ONH cellular proliferation and Jak-Stat pathway activation in this model. METHODS Chronic intraocular pressure (IOP) elevation was achieved via outflow pathway sclerosis. After 5 weeks, ONH longitudinal sections were immunolabeled with proliferation and cell-type markers to determine nuclear densities in the anterior (unmyelinated) and transition (partially myelinated) ONH. Nuclear pStat3 labeling was used to detect Jak-Stat pathway activation. Nuclear density differences between control ONH (uninjected) and ONH with either early or advanced injury (determined by optic nerve injury grading) were identified by ANOVA. RESULTS Advanced injury ONH had twice the nuclear density (P < 0.0001) of controls and significantly greater astrocyte density in anterior (P = 0.0001) and transition (P = 0.006) ONH regions. An increased optic nerve injury grade positively correlated with increased microglia/macrophage density in anterior and transition ONH (P < 0.0001, both). Oligodendroglial density was unaffected. In glaucoma model ONH, 80% of anterior and 66% of transition region proliferating cells were astrocytes. Nuclear pStat3 labeling significantly increased in early injury anterior ONH, and 95% colocalized with astrocytes. CONCLUSIONS Astrocytes account for the majority of proliferating cells, contributing to a doubled nuclear density in advanced injury ONH. Jak-Stat pathway activation is apparent in the early injury glaucoma model ONH. These data confirm dramatic astrocyte cell proliferation and early Jak-Stat pathway activation in ONH injured by elevated IOP.
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Affiliation(s)
- Diana C. Lozano
- Casey Eye Institute, Oregon Health & Science University, Portland, Oregon, United States
| | - Tiffany E. Choe
- Casey Eye Institute, Oregon Health & Science University, Portland, Oregon, United States
| | - William O. Cepurna
- Casey Eye Institute, Oregon Health & Science University, Portland, Oregon, United States
| | - John C. Morrison
- Casey Eye Institute, Oregon Health & Science University, Portland, Oregon, United States
| | - Elaine C. Johnson
- Casey Eye Institute, Oregon Health & Science University, Portland, Oregon, United States
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25
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Mahan VL. Neurointegrity and neurophysiology: astrocyte, glutamate, and carbon monoxide interactions. Med Gas Res 2019; 9:24-45. [PMID: 30950417 PMCID: PMC6463446 DOI: 10.4103/2045-9912.254639] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Accepted: 02/15/2019] [Indexed: 12/27/2022] Open
Abstract
Astrocyte contributions to brain function and prevention of neuropathologies are as extensive as that of neurons. Astroglial regulation of glutamate, a primary neurotransmitter, is through uptake, release through vesicular and non-vesicular pathways, and catabolism to intermediates. Homeostasis by astrocytes is considered to be of primary importance in determining normal central nervous system health and central nervous system physiology - glutamate is central to dynamic physiologic changes and central nervous system stability. Gasotransmitters may affect diverse glutamate interactions positively or negatively. The effect of carbon monoxide, an intrinsic central nervous system gasotransmitter, in the complex astrocyte homeostasis of glutamate may offer insights to normal brain development, protection, and its use as a neuromodulator and neurotherapeutic. In this article, we will review the effects of carbon monoxide on astrocyte homeostasis of glutamate.
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Affiliation(s)
- Vicki L. Mahan
- Division of Pediatric Cardiothoracic Surgery in the Department of Surgery, St. Christopher's Hospital for Children/Drexel University College of Medicine, Philadelphia, PA, USA
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26
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Sharipov RR, Krasilnikova IA, Pinelis VG, Gorbacheva LR, Surin AM. Study of the Mechanism of the Neuron Sensitization to the Repeated Glutamate Challenge. BIOCHEMISTRY MOSCOW SUPPLEMENT SERIES A-MEMBRANE AND CELL BIOLOGY 2018. [DOI: 10.1134/s1990747818050057] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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27
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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] [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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