151
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Ahmadpour N, Kantroo M, Stobart JL. Extracellular Calcium Influx Pathways in Astrocyte Calcium Microdomain Physiology. Biomolecules 2021; 11:1467. [PMID: 34680100 PMCID: PMC8533159 DOI: 10.3390/biom11101467] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2021] [Revised: 09/25/2021] [Accepted: 10/01/2021] [Indexed: 02/08/2023] Open
Abstract
Astrocytes are complex glial cells that play many essential roles in the brain, including the fine-tuning of synaptic activity and blood flow. These roles are linked to fluctuations in intracellular Ca2+ within astrocytes. Recent advances in imaging techniques have identified localized Ca2+ transients within the fine processes of the astrocytic structure, which we term microdomain Ca2+ events. These Ca2+ transients are very diverse and occur under different conditions, including in the presence or absence of surrounding circuit activity. This complexity suggests that different signalling mechanisms mediate microdomain events which may then encode specific astrocyte functions from the modulation of synapses up to brain circuits and behaviour. Several recent studies have shown that a subset of astrocyte microdomain Ca2+ events occur rapidly following local neuronal circuit activity. In this review, we consider the physiological relevance of microdomain astrocyte Ca2+ signalling within brain circuits and outline possible pathways of extracellular Ca2+ influx through ionotropic receptors and other Ca2+ ion channels, which may contribute to astrocyte microdomain events with potentially fast dynamics.
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Affiliation(s)
| | | | - Jillian L. Stobart
- College of Pharmacy, Rady Faculty of Health Sciences, University of Manitoba, 750 McDermot Avenue, Winnipeg, MG R3E 0T5, Canada; (N.A.); (M.K.)
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152
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Li F, Geng X, Yun HJ, Haddad Y, Chen Y, Ding Y. Neuroplastic Effect of Exercise Through Astrocytes Activation and Cellular Crosstalk. Aging Dis 2021; 12:1644-1657. [PMID: 34631212 PMCID: PMC8460294 DOI: 10.14336/ad.2021.0325] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Accepted: 03/25/2021] [Indexed: 12/21/2022] Open
Abstract
Physical exercise is an effective therapy for neurorehabilitation. Exercise has been shown to induce remodeling and proliferation of astrocyte. Astrocytes potentially affect the recruitment and function of neurons; they could intensify responses of neurons and bring more neurons for the process of neuroplasticity. Interactions between astrocytes, microglia and neurons modulate neuroplasticity and, subsequently, neural circuit function. These cellular interactions promote the number and function of synapses, neurogenesis, and cerebrovascular remodeling. However, the roles and crosstalk of astrocytes with neurons and microglia and any subsequent neuroplastic effects have not been studied extensively in exercise-induced settings. This article discusses the impact of physical exercise on astrocyte proliferation and highlights the interplay between astrocytes, microglia and neurons. The crosstalk between these cells may enhance neuroplasticity, leading to the neuroplastic effects of exercise.
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Affiliation(s)
- Fengwu Li
- China-America Institute of Neuroscience, Luhe Hospital, Capital Medical University, Beijing, China.
- Department of Developmental Cell Biology, Key Laboratory of Cell Biology, Ministry of Public Health, and Key Laboratory of Medical Cell Biology, Ministry of Education, China Medical University, Shenyang, China
| | - Xiaokun Geng
- China-America Institute of Neuroscience, Luhe Hospital, Capital Medical University, Beijing, China.
- Department of Neurology, Beijing Luhe Hospital, Capital Medical University, China.
- Department of Neurosurgery, Wayne State University School of Medicine, Detroit, MI, USA.
| | - Ho Jun Yun
- Department of Neurosurgery, Wayne State University School of Medicine, Detroit, MI, USA.
| | - Yazeed Haddad
- Department of Neurosurgery, Wayne State University School of Medicine, Detroit, MI, USA.
| | - Yuhua Chen
- Department of Developmental Cell Biology, Key Laboratory of Cell Biology, Ministry of Public Health, and Key Laboratory of Medical Cell Biology, Ministry of Education, China Medical University, Shenyang, China
| | - Yuchuan Ding
- Department of Neurosurgery, Wayne State University School of Medicine, Detroit, MI, USA.
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153
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Liu X, Ying J, Wang X, Zheng Q, Zhao T, Yoon S, Yu W, Yang D, Fang Y, Hua F. Astrocytes in Neural Circuits: Key Factors in Synaptic Regulation and Potential Targets for Neurodevelopmental Disorders. Front Mol Neurosci 2021; 14:729273. [PMID: 34658786 PMCID: PMC8515196 DOI: 10.3389/fnmol.2021.729273] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Accepted: 09/02/2021] [Indexed: 12/14/2022] Open
Abstract
Astrocytes are the major glial cells in the brain, which play a supporting role in the energy and nutritional supply of neurons. They were initially regarded as passive space-filling cells, but the latest progress in the study of the development and function of astrocytes highlights their active roles in regulating synaptic transmission, formation, and plasticity. In the concept of "tripartite synapse," the bidirectional influence between astrocytes and neurons, in addition to their steady-state and supporting function, suggests that any negative changes in the structure or function of astrocytes will affect the activity of neurons, leading to neurodevelopmental disorders. The role of astrocytes in the pathophysiology of various neurological and psychiatric disorders caused by synaptic defects is increasingly appreciated. Understanding the roles of astrocytes in regulating synaptic development and the plasticity of neural circuits could help provide new treatments for these diseases.
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Affiliation(s)
- Xing Liu
- Department of Anesthesiology, The Second Affiliated Hospital of Nanchang University, Nanchang, China
- Key Laboratory of Anesthesiology of Jiangxi Province, Nanchang, China
| | - Jun Ying
- Department of Anesthesiology, The Second Affiliated Hospital of Nanchang University, Nanchang, China
- Key Laboratory of Anesthesiology of Jiangxi Province, Nanchang, China
| | - Xifeng Wang
- Department of Anesthesiology, The First Affiliated Hospital of Nanchang University, Nanchang, China
| | - Qingcui Zheng
- Department of Anesthesiology, The Second Affiliated Hospital of Nanchang University, Nanchang, China
- Key Laboratory of Anesthesiology of Jiangxi Province, Nanchang, China
| | - Tiancheng Zhao
- Mailman School of Public Health, Columbia University, New York, NY, United States
| | - Sungtae Yoon
- Helping Minds International Charitable Foundation, New York, NY, United States
| | - Wen Yu
- Department of Anesthesiology, The Second Affiliated Hospital of Nanchang University, Nanchang, China
- Key Laboratory of Anesthesiology of Jiangxi Province, Nanchang, China
| | - Danying Yang
- Department of Anesthesiology, The Second Affiliated Hospital of Nanchang University, Nanchang, China
- Key Laboratory of Anesthesiology of Jiangxi Province, Nanchang, China
| | - Yang Fang
- Department of Anesthesiology, The Second Affiliated Hospital of Nanchang University, Nanchang, China
- Key Laboratory of Anesthesiology of Jiangxi Province, Nanchang, China
| | - Fuzhou Hua
- Department of Anesthesiology, The Second Affiliated Hospital of Nanchang University, Nanchang, China
- Key Laboratory of Anesthesiology of Jiangxi Province, Nanchang, China
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154
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Akther S, Hirase H. Assessment of astrocytes as a mediator of memory and learning in rodents. Glia 2021; 70:1484-1505. [PMID: 34582594 DOI: 10.1002/glia.24099] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Revised: 09/15/2021] [Accepted: 09/16/2021] [Indexed: 12/26/2022]
Abstract
The classical view of astrocytes is that they provide supportive functions for neurons, transporting metabolites and maintaining the homeostasis of the extracellular milieu. This view is gradually changing with the advent of molecular genetics and optical methods allowing interrogation of selected cell types in live experimental animals. An emerging view that astrocytes additionally act as a mediator of synaptic plasticity and contribute to learning processes has gained in vitro and in vivo experimental support. Here we focus on the literature published in the past two decades to review the roles of astrocytes in brain plasticity in rodents, whereby the roles of neurotransmitters and neuromodulators are considered to be comparable to those in humans. We outline established inputs and outputs of astrocytes and discuss how manipulations of astrocytes have impacted the behavior in various learning paradigms. Multiple studies suggest that the contribution of astrocytes has a considerably longer time course than neuronal activation, indicating metabolic roles of astrocytes. We advocate that exploring upstream and downstream mechanisms of astrocytic activation will further provide insight into brain plasticity and memory/learning impairment.
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Affiliation(s)
- Sonam Akther
- Center for Translational Neuromedicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Hajime Hirase
- Center for Translational Neuromedicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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155
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Potential of Multiscale Astrocyte Imaging for Revealing Mechanisms Underlying Neurodevelopmental Disorders. Int J Mol Sci 2021; 22:ijms221910312. [PMID: 34638653 PMCID: PMC8508625 DOI: 10.3390/ijms221910312] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2021] [Revised: 09/21/2021] [Accepted: 09/22/2021] [Indexed: 01/18/2023] Open
Abstract
Astrocytes provide trophic and metabolic support to neurons and modulate circuit formation during development. In addition, astrocytes help maintain neuronal homeostasis through neurovascular coupling, blood-brain barrier maintenance, clearance of metabolites and nonfunctional proteins via the glymphatic system, extracellular potassium buffering, and regulation of synaptic activity. Thus, astrocyte dysfunction may contribute to a myriad of neurological disorders. Indeed, astrocyte dysfunction during development has been implicated in Rett disease, Alexander's disease, epilepsy, and autism, among other disorders. Numerous disease model mice have been established to investigate these diseases, but important preclinical findings on etiology and pathophysiology have not translated into clinical interventions. A multidisciplinary approach is required to elucidate the mechanism of these diseases because astrocyte dysfunction can result in altered neuronal connectivity, morphology, and activity. Recent progress in neuroimaging techniques has enabled noninvasive investigations of brain structure and function at multiple spatiotemporal scales, and these technologies are expected to facilitate the translation of preclinical findings to clinical studies and ultimately to clinical trials. Here, we review recent progress on astrocyte contributions to neurodevelopmental and neuropsychiatric disorders revealed using novel imaging techniques, from microscopy scale to mesoscopic scale.
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156
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Van Den Herrewegen Y, Sanderson TM, Sahu S, De Bundel D, Bortolotto ZA, Smolders I. Side-by-side comparison of the effects of Gq- and Gi-DREADD-mediated astrocyte modulation on intracellular calcium dynamics and synaptic plasticity in the hippocampal CA1. Mol Brain 2021; 14:144. [PMID: 34544455 PMCID: PMC8451082 DOI: 10.1186/s13041-021-00856-w] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Accepted: 09/11/2021] [Indexed: 12/12/2022] Open
Abstract
Astrocytes express a plethora of G protein-coupled receptors (GPCRs) that are crucial for shaping synaptic activity. Upon GPCR activation, astrocytes can respond with transient variations in intracellular Ca2+. In addition, Ca2+-dependent and/or Ca2+-independent release of gliotransmitters can occur, allowing them to engage in bidirectional neuron-astrocyte communication. The development of designer receptors exclusively activated by designer drugs (DREADDs) has facilitated many new discoveries on the roles of astrocytes in both physiological and pathological conditions. They are an excellent tool, as they can target endogenous GPCR-mediated intracellular signal transduction pathways specifically in astrocytes. With increasing interest and accumulating research on this topic, several discrepancies on astrocytic Ca2+ signalling and astrocyte-mediated effects on synaptic plasticity have emerged, preventing a clear-cut consensus about the downstream effects of DREADDs in astrocytes. In the present study, we performed a side-by-side evaluation of the effects of bath application of the DREADD agonist, clozapine-N-oxide (10 µM), on Gq- and Gi-DREADD activation in mouse CA1 hippocampal astrocytes. In doing so, we aimed to avoid confounding factors, such as differences in experimental procedures, and to directly compare the actions of both DREADDs on astrocytic intracellular Ca2+ dynamics and synaptic plasticity in acute hippocampal slices. We used an adeno-associated viral vector approach to transduce dorsal hippocampi of male, 8-week-old C57BL6/J mice, to drive expression of either the Gq-DREADD or Gi-DREADD in CA1 astrocytes. A viral vector lacking the DREADD construct was used to generate controls. Here, we show that agonism of Gq-DREADDs, but not Gi-DREADDs, induced consistent increases in spontaneous astrocytic Ca2+ events. Moreover, we demonstrate that both Gq-DREADD as well as Gi-DREADD-mediated activation of CA1 astrocytes induces long-lasting synaptic potentiation in the hippocampal CA1 Schaffer collateral pathway in the absence of a high frequency stimulus. Moreover, we report for the first time that astrocytic Gi-DREADD activation is sufficient to elicit de novo potentiation. Our data demonstrate that activation of either Gq or Gi pathways drives synaptic potentiation through Ca2+-dependent and Ca2+-independent mechanisms, respectively.
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Affiliation(s)
- Yana Van Den Herrewegen
- Department of Pharmaceutical Chemistry, Drug Analysis and Drug Information, Research Group Experimental Pharmacology, Center for Neurosciences (C4N), Vrije Universiteit Brussel (VUB), Laarbeeklaan 103, 1090, Brussels, Belgium
| | - Thomas M Sanderson
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Tankard's Cl, University Walk, BS8 1TD, Bristol, UK
| | - Surajit Sahu
- Department of Pharmaceutical Chemistry, Drug Analysis and Drug Information, Research Group Experimental Pharmacology, Center for Neurosciences (C4N), Vrije Universiteit Brussel (VUB), Laarbeeklaan 103, 1090, Brussels, Belgium
| | - Dimitri De Bundel
- Department of Pharmaceutical Chemistry, Drug Analysis and Drug Information, Research Group Experimental Pharmacology, Center for Neurosciences (C4N), Vrije Universiteit Brussel (VUB), Laarbeeklaan 103, 1090, Brussels, Belgium
| | - Zuner A Bortolotto
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Tankard's Cl, University Walk, BS8 1TD, Bristol, UK
| | - Ilse Smolders
- Department of Pharmaceutical Chemistry, Drug Analysis and Drug Information, Research Group Experimental Pharmacology, Center for Neurosciences (C4N), Vrije Universiteit Brussel (VUB), Laarbeeklaan 103, 1090, Brussels, Belgium.
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157
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Mielnicka A, Michaluk P. Exocytosis in Astrocytes. Biomolecules 2021; 11:1367. [PMID: 34572580 PMCID: PMC8471187 DOI: 10.3390/biom11091367] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Revised: 09/10/2021] [Accepted: 09/14/2021] [Indexed: 12/17/2022] Open
Abstract
Until recently, astrocytes were thought to be a part of a simple "brain glue" providing only a supporting role for neurons. However, the discoveries of the last two decades have proven astrocytes to be dynamic partners participating in brain metabolism and actively influencing communication between neurons. The means of astrocyte-neuron communication are diverse, although regulated exocytosis has received the most attention but also caused the most debate. Similar to most of eukaryotic cells, astrocytes have a complex range of vesicular organelles which can undergo exocytosis as well as intricate molecular mechanisms that regulate this process. In this review, we focus on the components needed for regulated exocytosis to occur and summarise the knowledge about experimental evidence showing its presence in astrocytes.
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Affiliation(s)
| | - Piotr Michaluk
- BRAINCITY, Laboratory of Neurobiology, The Nencki Institute of Experimental Biology, PAS, 02-093 Warsaw, Poland;
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158
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Zhang D, Chen Q, Bi Y, Zhang H, Chen M, Wan J, Shi C, Zhang W, Zhang J, Qiao Z, Li J, Chen S, Liu R. Bio-inspired poly-DL-serine materials resist the foreign-body response. Nat Commun 2021; 12:5327. [PMID: 34493717 PMCID: PMC8423817 DOI: 10.1038/s41467-021-25581-9] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Accepted: 08/02/2021] [Indexed: 11/09/2022] Open
Abstract
Implantation-caused foreign-body response (FBR) is a commonly encountered issue and can result in failure of implants. The high L-serine content in low immunogenic silk sericin, and the high D-serine content as a neurotransmitter together inspire us to prepare poly-DL-serine (PSer) materials in mitigating the FBR. Here we report highly water soluble, biocompatible and easily accessible PSer hydrogels that cause negligible inflammatory response after subcutaneous implantation in mice for 1 week and 2 weeks. No obvious collagen capsulation is found surrounding the PSer hydrogels after 4 weeks, 3 months and 7 months post implantation. Histological analysis on inflammatory cytokines and RNA-seq assay both indicate that PSer hydrogels show low FBR, comparable to the Mock group. The anti-FBR performance of PSer hydrogels at all time points surpass the poly(ethyleneglycol) hydrogels that is widely utilized as bio-inert materials, implying the potent and wide application of PSer materials in implantable biomaterials and biomedical devices.
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Affiliation(s)
- Donghui Zhang
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China
| | - Qi Chen
- Key Laboratory for Ultrafine Materials of Ministry of Education, Frontiers Science Center for Materiobiology and Dynamic Chemistry, Research Center for Biomedical Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai, China
| | - Yufang Bi
- Key Laboratory for Ultrafine Materials of Ministry of Education, Frontiers Science Center for Materiobiology and Dynamic Chemistry, Research Center for Biomedical Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai, China
| | - Haodong Zhang
- Key Laboratory for Ultrafine Materials of Ministry of Education, Frontiers Science Center for Materiobiology and Dynamic Chemistry, Research Center for Biomedical Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai, China
| | - Minzhang Chen
- Key Laboratory for Ultrafine Materials of Ministry of Education, Frontiers Science Center for Materiobiology and Dynamic Chemistry, Research Center for Biomedical Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai, China
| | - Jianglin Wan
- Key Laboratory for Ultrafine Materials of Ministry of Education, Frontiers Science Center for Materiobiology and Dynamic Chemistry, Research Center for Biomedical Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai, China
| | - Chao Shi
- Key Laboratory for Ultrafine Materials of Ministry of Education, Frontiers Science Center for Materiobiology and Dynamic Chemistry, Research Center for Biomedical Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai, China
| | - Wenjing Zhang
- Key Laboratory for Ultrafine Materials of Ministry of Education, Frontiers Science Center for Materiobiology and Dynamic Chemistry, Research Center for Biomedical Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai, China
| | - Junyu Zhang
- Key Laboratory for Ultrafine Materials of Ministry of Education, Frontiers Science Center for Materiobiology and Dynamic Chemistry, Research Center for Biomedical Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai, China
| | - Zhongqian Qiao
- Key Laboratory for Ultrafine Materials of Ministry of Education, Frontiers Science Center for Materiobiology and Dynamic Chemistry, Research Center for Biomedical Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai, China
| | - Jin Li
- Shanghai Key Laboratory of Orbital Diseases and Ocular Oncology, Department of Ophthalmology, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Shengfu Chen
- Key Laboratory of Biomass Chemical Engineering of Ministry of Education, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou, Zhejiang, China
| | - Runhui Liu
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China. .,Key Laboratory for Ultrafine Materials of Ministry of Education, Frontiers Science Center for Materiobiology and Dynamic Chemistry, Research Center for Biomedical Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai, China.
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159
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Gerasimov E, Erofeev A, Borodinova A, Bolshakova A, Balaban P, Bezprozvanny I, Vlasova OL. Optogenetic Activation of Astrocytes-Effects on Neuronal Network Function. Int J Mol Sci 2021; 22:9613. [PMID: 34502519 PMCID: PMC8431749 DOI: 10.3390/ijms22179613] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Revised: 08/24/2021] [Accepted: 09/01/2021] [Indexed: 01/04/2023] Open
Abstract
Optogenetics approach is used widely in neurobiology as it allows control of cellular activity with high spatial and temporal resolution. In most studies, optogenetics is used to control neuronal activity. In the present study optogenetics was used to stimulate astrocytes with the aim to modulate neuronal activity. To achieve this goal, light stimulation was applied to astrocytes expressing a version of ChR2 (ionotropic opsin) or Opto-α1AR (metabotropic opsin). Optimal optogenetic stimulation parameters were determined using patch-clamp recordings of hippocampal pyramidal neurons' spontaneous activity in brain slices as a readout. It was determined that the greatest increase in the number of spontaneous synaptic currents was observed when astrocytes expressing ChR2(H134R) were activated by 5 s of continuous light. For the astrocytes expressing Opto-α1AR, the greatest response was observed in the pulse stimulation mode (T = 1 s, t = 100 ms). It was also observed that activation of the astrocytic Opto-a1AR but not ChR2 results in an increase of the fEPSP slope in hippocampal neurons. Based on these results, we concluded that Opto-a1AR expressed in hippocampal astrocytes provides an opportunity to modulate the long-term synaptic plasticity optogenetically, and may potentially be used to normalize the synaptic transmission and plasticity defects in a variety of neuropathological conditions, including models of Alzheimer's disease and other neurodegenerative disorders.
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Affiliation(s)
- Evgenii Gerasimov
- Laboratory of Molecular Neurodegeneration, Peter the Great St. Petersburg Polytechnic University, Khlopina St. 11, 194021 St. Petersburg, Russia; (A.E.); (A.B.); (I.B.)
| | - Alexander Erofeev
- Laboratory of Molecular Neurodegeneration, Peter the Great St. Petersburg Polytechnic University, Khlopina St. 11, 194021 St. Petersburg, Russia; (A.E.); (A.B.); (I.B.)
| | - Anastasia Borodinova
- Cellular Neurobiology of Learning Lab, Institute of Higher Nervous Activity and Neurophysiology of the Russian Academy of Science, Butlerova St. 5A, 117485 Moscow, Russia; (A.B.); (P.B.)
| | - Anastasia Bolshakova
- Laboratory of Molecular Neurodegeneration, Peter the Great St. Petersburg Polytechnic University, Khlopina St. 11, 194021 St. Petersburg, Russia; (A.E.); (A.B.); (I.B.)
| | - Pavel Balaban
- Cellular Neurobiology of Learning Lab, Institute of Higher Nervous Activity and Neurophysiology of the Russian Academy of Science, Butlerova St. 5A, 117485 Moscow, Russia; (A.B.); (P.B.)
| | - Ilya Bezprozvanny
- Laboratory of Molecular Neurodegeneration, Peter the Great St. Petersburg Polytechnic University, Khlopina St. 11, 194021 St. Petersburg, Russia; (A.E.); (A.B.); (I.B.)
- Department of Physiology, UT Southwestern Medical Center at Dallas, Dallas, TX 75390, USA
| | - Olga L. Vlasova
- Laboratory of Molecular Neurodegeneration, Peter the Great St. Petersburg Polytechnic University, Khlopina St. 11, 194021 St. Petersburg, Russia; (A.E.); (A.B.); (I.B.)
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160
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Fritschi L, Lindmar JH, Scheidl F, Lenk K. Neuronal and Astrocytic Regulations in Schizophrenia: A Computational Modelling Study. Front Cell Neurosci 2021; 15:718459. [PMID: 34512269 PMCID: PMC8428975 DOI: 10.3389/fncel.2021.718459] [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: 05/31/2021] [Accepted: 07/26/2021] [Indexed: 11/15/2022] Open
Abstract
According to the tripartite synapse model, astrocytes have a modulatory effect on neuronal signal transmission. More recently, astrocyte malfunction has been associated with psychiatric diseases such as schizophrenia. Several hypotheses have been proposed on the pathological mechanisms of astrocytes in schizophrenia. For example, post-mortem examinations have revealed a reduced astrocytic density in patients with schizophrenia. Another hypothesis suggests that disease symptoms are linked to an abnormality of glutamate transmission, which is also regulated by astrocytes (glutamate hypothesis of schizophrenia). Electrophysiological findings indicate a dispute over whether the disorder causes an increase or a decrease in neuronal and astrocytic activity. Moreover, there is no consensus as to which molecular pathways and network mechanisms are altered in schizophrenia. Computational models can aid the process in finding the underlying pathological malfunctions. The effect of astrocytes on the activity of neuron-astrocyte networks has been analysed with computational models. These can reproduce experimentally observed phenomena, such as astrocytic modulation of spike and burst signalling in neuron-astrocyte networks. Using an established computational neuron-astrocyte network model, we simulate experimental data of healthy and pathological networks by using different neuronal and astrocytic parameter configurations. In our simulations, the reduction of neuronal or astrocytic cell densities yields decreased glutamate levels and a statistically significant reduction in the network activity. Amplifications of the astrocytic ATP release toward postsynaptic terminals also reduced the network activity and resulted in temporarily increased glutamate levels. In contrast, reducing either the glutamate release or re-uptake in astrocytes resulted in higher network activities. Similarly, an increase in synaptic weights of excitatory or inhibitory neurons raises the excitability of individual cells and elevates the activation level of the network. To conclude, our simulations suggest that the impairment of both neurons and astrocytes disturbs the neuronal network activity in schizophrenia.
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Affiliation(s)
- Lea Fritschi
- Department of Mathematics, ETH Zurich, Zurich, Switzerland
| | | | - Florian Scheidl
- Department of Computer Science, ETH Zurich, Zurich, Switzerland
| | - Kerstin Lenk
- Computational Biophysics and Imaging Group (CBIG), Faculty of Medicine and Health Technology, BioMediTech, Tampere University, Tampere, Finland
- Institute of Neural Engineering, Graz University of Technology, Graz, Austria
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161
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Müller FE, Cherkas V, Stopper G, Caudal LC, Stopper L, Kirchhoff F, Henneberger C, Ponimaskin EG, Zeug A. Elucidating regulators of astrocytic Ca 2+ signaling via multi-threshold event detection (MTED). Glia 2021; 69:2798-2811. [PMID: 34388285 DOI: 10.1002/glia.24070] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Revised: 07/26/2021] [Accepted: 07/28/2021] [Indexed: 01/23/2023]
Abstract
Recent achievements in indicator optimization and imaging techniques promote the advancement of functional imaging to decipher complex signaling processes in living cells, such as Ca2+ activity patterns. Astrocytes are important regulators of the brain network and well known for their highly complex morphology and spontaneous Ca2+ activity. However, the astrocyte community is lacking standardized methods to analyze and interpret Ca2+ activity recordings, hindering global comparisons. Here, we present a biophysically-based analytical concept for deciphering the complex spatio-temporal changes of Ca2+ biosensor fluorescence for understanding the underlying signaling mechanisms. We developed a pixel-based multi-threshold event detection (MTED) analysis of multidimensional data, which accounts for signal strength as an additional signaling dimension and provides the experimenter with a comprehensive toolbox for a differentiated and in-depth characterization of fluorescence signals. MTED was validated by analyzing astrocytic Ca2+ activity across Ca2+ indicators, imaging setups, and model systems from primary cell culture to awake, head-fixed mice. We identified extended Ca2+ activity at 25°C compared to 37°C physiological body temperature and dissected how neuronal activity shapes long-lasting astrocytic Ca2+ activity. Our MTED strategy, as a parameter-free approach, is easily transferrable to other fluorescent indicators and biosensors and embraces the additional dimensionality of signaling activity strength. It will also advance the definition of standardized procedures and parameters to improve comparability of research data and reports.
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Affiliation(s)
| | - Volodymyr Cherkas
- Cellular Neurophysiology, Hannover Medical School, Hannover, Germany
| | - Gebhard Stopper
- Department of Molecular Physiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), University of Saarland, Homburg, Germany
| | - Laura C Caudal
- Department of Molecular Physiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), University of Saarland, Homburg, Germany
| | - Laura Stopper
- Department of Molecular Physiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), University of Saarland, Homburg, Germany
| | - Frank Kirchhoff
- Department of Molecular Physiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), University of Saarland, Homburg, 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, UK
| | | | - Andre Zeug
- Cellular Neurophysiology, Hannover Medical School, Hannover, Germany
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162
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Shin TH, Lee DY, Manavalan B, Basith S, Na YC, Yoon C, Lee HS, Paik MJ, Lee G. Silica-coated magnetic nanoparticles activate microglia and induce neurotoxic D-serine secretion. Part Fibre Toxicol 2021; 18:30. [PMID: 34384435 PMCID: PMC8359100 DOI: 10.1186/s12989-021-00420-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Accepted: 07/13/2021] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Nanoparticles have been studied for brain imaging, diagnosis, and drug delivery owing to their versatile properties due to their small sizes. However, there are growing concerns that nanoparticles may exert toxic effects in the brain. In this study, we assessed direct nanotoxicity on microglia, the resident macrophages of the central nervous system, and indirect toxicity on neuronal cells exerted by silica-coated magnetic nanoparticles containing rhodamine B isothiocyanate dye [MNPs@SiO2(RITC)]. METHODS We investigated MNPs@SiO2(RITC)-induced biological changes in BV2 murine microglial cells via RNA-sequencing-based transcriptome analysis and gas chromatography-mass spectrometry-based intracellular and extracellular amino acid profiling. Morphological changes were analyzed by transmission electron microscopy. Indirect effects of MNPs@SiO2(RITC) on neuronal cells were assessed by Transwell-based coculture with MNPs@SiO2(RITC)-treated microglia. MNPs@SiO2(RITC)-induced biological changes in the mouse brain in vivo were examined by immunohistochemical analysis. RESULTS BV2 murine microglial cells were morphologically activated and the expression of Iba1, an activation marker protein, was increased after MNPs@SiO2(RITC) treatment. Transmission electron microscopy analysis revealed lysosomal accumulation of MNPs@SiO2(RITC) and the formation of vesicle-like structures in MNPs@SiO2(RITC)-treated BV2 cells. The expression of several genes related to metabolism and inflammation were altered in 100 µg/ml MNPs@SiO2(RITC)-treated microglia when compared with that in non-treated (control) and 10 µg/ml MNPs@SiO2(RITC)-treated microglia. Combined transcriptome and amino acid profiling analyses revealed that the transport of serine family amino acids, including glycine, cysteine, and serine, was enhanced. However, only serine was increased in the growth medium of activated microglia; especially, excitotoxic D-serine secretion from primary rat microglia was the most strongly enhanced. Activated primary microglia reduced intracellular ATP levels and proteasome activity in cocultured neuronal cells, especially in primary cortical neurons, via D-serine secretion. Moreover, ubiquitinated proteins accumulated and inclusion bodies were increased in primary dopaminergic and cortical neurons cocultured with activated primary microglia. In vivo, MNPs@SiO2(RITC), D-serine, and ubiquitin aggresomes were distributed in the MNPs@SiO2(RITC)-treated mouse brain. CONCLUSIONS MNPs@SiO2(RITC)-induced activation of microglia triggers excitotoxicity in neurons via D-serine secretion, highlighting the importance of neurotoxicity mechanisms incurred by nanoparticle-induced microglial activation.
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Affiliation(s)
- Tae Hwan Shin
- Department of Physiology, Ajou University School of Medicine, 206 World cup-ro, 16499 Suwon, Republic of Korea
| | - Da Yeon Lee
- Department of Physiology, Ajou University School of Medicine, 206 World cup-ro, 16499 Suwon, Republic of Korea
| | - Balachandran Manavalan
- Department of Physiology, Ajou University School of Medicine, 206 World cup-ro, 16499 Suwon, Republic of Korea
| | - Shaherin Basith
- Department of Physiology, Ajou University School of Medicine, 206 World cup-ro, 16499 Suwon, Republic of Korea
| | - Yun-Cheol Na
- Western Seoul Center, Korea Basic Science Institute, 150 Bugahyeon-ro, 03759 Seoul, Republic of Korea
| | - Cheolho Yoon
- Ochang Center, Korea Basic Science Institute, 162 Yeongudanji-ro, 28119 Cheongju, Republic of Korea
| | - Hyeon-Seong Lee
- College of Pharmacy, Sunchon National University, 255 Jungang-ro, 57922 Suncheon, Republic of Korea
| | - Man Jeong Paik
- College of Pharmacy, Sunchon National University, 255 Jungang-ro, 57922 Suncheon, Republic of Korea
| | - Gwang Lee
- Department of Physiology, Ajou University School of Medicine, 206 World cup-ro, 16499 Suwon, Republic of Korea
- Department of Molecular Science and Technology, Ajou University, 206 World cup-ro, 16499 Suwon, Republic of Korea
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163
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Watkins JC, Evans RH, Bayés À, Booker SA, Gibb A, Mabb AM, Mayer M, Mellor JR, Molnár E, Niu L, Ortega A, Pankratov Y, Ramos-Vicente D, Rodríguez-Campuzano A, Rodríguez-Moreno A, Wang LY, Wang YT, Wollmuth L, Wyllie DJA, Zhuo M, Frenguelli BG. 21st century excitatory amino acid research: A Q & A with Jeff Watkins and Dick Evans. Neuropharmacology 2021; 198:108743. [PMID: 34363811 DOI: 10.1016/j.neuropharm.2021.108743] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
In 1981 Jeff Watkins and Dick Evans wrote what was to become a seminal review on excitatory amino acids (EAAs) and their receptors (Watkins and Evans, 1981). Bringing together various lines of evidence dating back over several decades on: the distribution in the nervous system of putative amino acid neurotransmitters; enzymes involved in their production and metabolism; the uptake and release of amino acids; binding of EAAs to membranes; the pharmacological action of endogenous excitatory amino acids and their synthetic analogues, and notably the actions of antagonists for the excitations caused by both nerve stimulation and exogenous agonists, often using pharmacological tools developed by Jeff and his colleagues, they provided a compelling account for EAAs, especially l-glutamate, as a bona fide neurotransmitter in the nervous system. The rest, as they say, is history, but far from being consigned to history, EAA research is in rude health well into the 21st Century as this series of Special Issues of Neuropharmacology exemplifies. With EAAs and their receptors flourishing across a wide range of disciplines and clinical conditions, we enter into a dialogue with two of the most prominent and influential figures in the early days of EAA research: Jeff Watkins and Dick Evans.
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Affiliation(s)
| | | | - Àlex Bayés
- Molecular Physiology of the Synapse Laboratory, Biomedical Research Institute Sant Pau, Barcelona, Spain and Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Sam A Booker
- Simons Initiative for the Developing Brain, Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, EH8 9XD, UK
| | - Alasdair Gibb
- Research Department of Neuroscience, Physiology & Pharmacology, University College London, Gower Street, London, WC1E 6BT, UK
| | - Angela M Mabb
- Neuroscience Institute, Georgia State University, Atlanta, GA, United States
| | - Mark Mayer
- Bldg 35A, Room 3D-904, 35A Convent Drive, NINDS, NIH, Bethesda, MD, 20892, USA
| | - Jack R Mellor
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Biomedical Sciences Building, University Walk, Bristol, BS8 1TD, UK
| | - Elek Molnár
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Biomedical Sciences Building, University Walk, Bristol, BS8 1TD, UK
| | - Li Niu
- Chemistry Department, University at Albany, SUNY, 1400 Washington Ave, Albany, NY, 12222, USA
| | - Arturo Ortega
- Department of Toxicology, Cinvestav, Mexico City, Mexico
| | - Yuriy Pankratov
- School of Life Sciences, University of Warwick, Coventry, CV4 7AL, UK
| | - David Ramos-Vicente
- Molecular Physiology of the Synapse Laboratory, Biomedical Research Institute Sant Pau, Barcelona, Spain and Universitat Autònoma de Barcelona, Barcelona, Spain
| | | | | | - Lu-Yang Wang
- Program in Neurosciences & Mental Health, SickKids Research Institute and Department of Physiology, University of Toronto, 555 University Ave, Toronto, Ontario, M5G 1X8, Canada
| | - Yu Tian Wang
- Department of Medicine, University of British Columbia, Vancouver, BC, V6T 2B5, Canada
| | - Lonnie Wollmuth
- Depts. of Neurobiology & Behavior and Biochemistry & Cell Biology, Center for Nervous System Disorders, Stony Brook University, Stony Brook, NY, 11794-5230, USA
| | - David J A Wyllie
- Simons Initiative for the Developing Brain, Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, EH8 9XD, UK
| | - Min Zhuo
- Institute of Brain Research, Qingdao International Academician Park, Qingdao, 266000, China
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164
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Postnikova TY, Griflyuk AV, Amakhin DV, Kovalenko AA, Soboleva EB, Zubareva OE, Zaitsev AV. Early Life Febrile Seizures Impair Hippocampal Synaptic Plasticity in Young Rats. Int J Mol Sci 2021; 22:8218. [PMID: 34360983 PMCID: PMC8347828 DOI: 10.3390/ijms22158218] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Revised: 07/27/2021] [Accepted: 07/28/2021] [Indexed: 01/04/2023] Open
Abstract
Febrile seizures (FSs) in early life are significant risk factors of neurological disorders and cognitive impairment in later life. However, existing data about the impact of FSs on the developing brain are conflicting. We aimed to investigate morphological and functional changes in the hippocampus of young rats exposed to hyperthermia-induced seizures at postnatal day 10. We found that FSs led to a slight morphological disturbance. The cell numbers decreased by 10% in the CA1 and hilus but did not reduce in the CA3 or dentate gyrus areas. In contrast, functional impairments were robust. Long-term potentiation (LTP) in CA3-CA1 synapses was strongly reduced, which we attribute to the insufficient activity of N-methyl-D-aspartate receptors (NMDARs). Using whole-cell recordings, we found higher desensitization of NMDAR currents in the FS group. Since the desensitization of NMDARs depends on subunit composition, we analyzed NMDAR current decays and gene expression of subunits, which revealed no differences between control and FS rats. We suggest that an increased desensitization is due to insufficient activation of the glycine site of NMDARs, as the application of D-serine, the glycine site agonist, allows the restoration of LTP to a control value. Our results reveal a new molecular mechanism of FS impact on the developing brain.
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Affiliation(s)
| | | | | | | | | | | | - Aleksey V. Zaitsev
- Sechenov Institute of Evolutionary Physiology and Biochemistry of RAS, 44, Toreza Prospekt, 194223 Saint Petersburg, Russia; (T.Y.P.); (A.V.G.); (D.V.A.); (A.A.K.); (E.B.S.); (O.E.Z.)
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165
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Durkee C, Kofuji P, Navarrete M, Araque A. Astrocyte and neuron cooperation in long-term depression. Trends Neurosci 2021; 44:837-848. [PMID: 34334233 DOI: 10.1016/j.tins.2021.07.004] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Revised: 07/06/2021] [Accepted: 07/07/2021] [Indexed: 01/28/2023]
Abstract
Activity-dependent long-term changes in synaptic transmission known as synaptic plasticity are fundamental processes in brain function and are recognized as the cellular basis of learning and memory. While the neuronal mechanisms underlying synaptic plasticity have been largely identified, the involvement of astrocytes in these processes has been less recognized. However, astrocytes are emerging as important cells that regulate synaptic function by interacting with neurons at tripartite synapses. In this review, we discuss recent evidence suggesting that astrocytes are necessary elements in long-term synaptic depression (LTD). We highlight the mechanistic heterogeneity of astrocyte contribution to this form of synaptic plasticity and propose that astrocytes are integral participants in LTD.
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Affiliation(s)
- Caitlin Durkee
- Department of Neuroscience, University of Minnesota, Minneapolis, MN 55455, USA
| | - Paulo Kofuji
- Department of Neuroscience, University of Minnesota, Minneapolis, MN 55455, USA
| | | | - Alfonso Araque
- Department of Neuroscience, University of Minnesota, Minneapolis, MN 55455, USA.
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166
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Astrocytic contribution to glutamate-related central respiratory chemoreception in vertebrates. Respir Physiol Neurobiol 2021; 294:103744. [PMID: 34302992 DOI: 10.1016/j.resp.2021.103744] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 07/01/2021] [Accepted: 07/18/2021] [Indexed: 12/24/2022]
Abstract
Central respiratory chemoreceptors play a key role in the respiratory homeostasis by sensing CO2 and H+ in brain and activating the respiratory neural network. This ability of specific brain regions to respond to acidosis and hypercapnia is based on neuronal and glial mechanisms. Several decades ago, glutamatergic transmission was proposed to be involved as a main mechanism in central chemoreception. However, a complete identification of mechanism has been elusive. At the rostral medulla, chemosensitive neurons of the retrotrapezoid nucleus (RTN) are glutamatergic and they are stimulated by ATP released by RTN astrocytes in response to hypercapnia. In addition, recent findings show that caudal medullary astrocytes in brainstem can also contribute as CO2 and H+ sensors that release D-serine and glutamate, both gliotransmitters able to activate the respiratory neural network. In this review, we describe the mammalian astrocytic glutamatergic contribution to the central respiratory chemoreception trying to trace in vertebrates the emergence of several components involved in this process.
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167
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Paumier A, Boisseau S, Jacquier-Sarlin M, Pernet-Gallay K, Buisson A, Albrieux M. Astrocyte-neuron interplay is critical for Alzheimer's disease pathogenesis and is rescued by TRPA1 channel blockade. Brain 2021; 145:388-405. [PMID: 34302466 DOI: 10.1093/brain/awab281] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Revised: 06/21/2021] [Accepted: 07/16/2021] [Indexed: 11/12/2022] Open
Abstract
The sequence of cellular dysfunctions in preclinical Alzheimer's disease must be understood if we are to plot new therapeutic routes. Hippocampal neuronal hyperactivity is one of the earliest events occurring during the preclinical stages of Alzheimer's disease in both humans and mouse models. The most common hypothesis describes amyloid β accumulation as the triggering factor of the disease but the effects of this accumulation and the cascade of events leading to cognitive decline remain unclear. In mice, we previously showed that amyloid β-dependent TRPA1 channel activation triggers hippocampal astrocyte hyperactivity, subsequently inducing hyperactivity in nearby neurons. In this work, we investigated the potential protection against Alzheimer's disease progression provided by early chronic pharmacological inhibition of TRPA1 channel. A specific inhibitor of TRPA1 channel (HC030031) was administered intraperitoneally from the onset of amyloid β overproduction in the APP/PS1-21 mouse model of Alzheimer's disease. Short-, medium-, and long-term effects of this chronic pharmacological TRPA1 blockade were characterized on Alzheimer's disease progression at functional (astrocytic and neuronal activity), structural, biochemical, and behavioural levels. Our results revealed that the first observable disruptions in the Alzheimer's disease transgenic mouse model used correspond to aberrant hippocampal astrocyte and neuron hyperactivity. We showed that chronic TRPA1 blockade normalizes astrocytic activity, avoids perisynaptic astrocytic process withdrawal, prevents neuronal dysfunction and preserves structural synaptic integrity. These protective effects preserved spatial working-memory in this Alzheimer's disease mouse model. The toxic effect of amyloid β on astrocytes triggered by TRPA1 channel activation is pivotal to Alzheimer's disease progression. TRPA1 blockade prevents irreversible neuronal dysfunction, making this channel a potential therapeutic target to promote neuroprotection.
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Affiliation(s)
- Adrien Paumier
- Univ. Grenoble Alpes, Inserm, U1216, Grenoble Institut Neurosciences, GIN, 38000 Grenoble, France
| | - Sylvie Boisseau
- Univ. Grenoble Alpes, Inserm, U1216, Grenoble Institut Neurosciences, GIN, 38000 Grenoble, France
| | - Muriel Jacquier-Sarlin
- Univ. Grenoble Alpes, Inserm, U1216, Grenoble Institut Neurosciences, GIN, 38000 Grenoble, France
| | - Karin Pernet-Gallay
- Univ. Grenoble Alpes, Inserm, U1216, Grenoble Institut Neurosciences, GIN, 38000 Grenoble, France
| | - Alain Buisson
- Univ. Grenoble Alpes, Inserm, U1216, Grenoble Institut Neurosciences, GIN, 38000 Grenoble, France
| | - Mireille Albrieux
- Univ. Grenoble Alpes, Inserm, U1216, Grenoble Institut Neurosciences, GIN, 38000 Grenoble, France
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168
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Pereira MF, Amaral IM, Lopes C, Leitão C, Madeira D, Lopes JP, Gonçalves FQ, Canas PM, Cunha RA, Agostinho P. l-α-aminoadipate causes astrocyte pathology with negative impact on mouse hippocampal synaptic plasticity and memory. FASEB J 2021; 35:e21726. [PMID: 34196433 DOI: 10.1096/fj.202100336r] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2021] [Revised: 05/12/2021] [Accepted: 05/24/2021] [Indexed: 12/26/2022]
Abstract
Increasing evidence shows that astrocytes, by releasing and uptaking neuroactive molecules, regulate synaptic plasticity, considered the neurophysiological basis of memory. This study investigated the impact of l-α-aminoadipate (l-AA) on astrocytes which sense and respond to stimuli at the synaptic level and modulate hippocampal long-term potentiation (LTP) and memory. l-AA selectivity toward astrocytes was proposed in the early 70's and further tested in different systems. Although it has been used for impairing the astrocytic function, its effects appear to be variable in different brain regions. To test the effects of l-AA in the hippocampus of male C57Bl/6 mice we performed two different treatments (ex vivo and in vivo) and took advantage of other compounds that were reported to affect astrocytes. l-AA superfusion did not affect the basal synaptic transmission but decreased LTP magnitude. Likewise, trifluoroacetate and dihydrokainate decreased LTP magnitude and occluded the effect of l-AA on synaptic plasticity, confirming l-AA selectivity. l-AA superfusion altered astrocyte morphology, increasing the length and complexity of their processes. In vivo, l-AA intracerebroventricular injection not only reduced the astrocytic markers but also LTP magnitude and impaired hippocampal-dependent memory in mice. Interestingly, d-serine administration recovered hippocampal LTP reduction triggered by l-AA (2 h exposure in hippocampal slices), whereas in mice injected with l-AA, the superfusion of d-serine did not fully rescue LTP magnitude. Overall, these data show that both l-AA treatments affect astrocytes differently, astrocytic activation or loss, with similar negative outcomes on hippocampal LTP, implying that opposite astrocytic adaptive alterations are equally detrimental for synaptic plasticity.
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Affiliation(s)
| | - Inês M Amaral
- Center for Neuroscience and Cell Biology, CNC, Coimbra, Portugal
| | - Cátia Lopes
- Center for Neuroscience and Cell Biology, CNC, Coimbra, Portugal
| | - Catarina Leitão
- Center for Neuroscience and Cell Biology, CNC, Coimbra, Portugal
| | - Daniela Madeira
- Center for Neuroscience and Cell Biology, CNC, Coimbra, Portugal.,Faculty of Medicine, University of Coimbra, FMUC, Coimbra, Portugal
| | - João P Lopes
- Center for Neuroscience and Cell Biology, CNC, Coimbra, Portugal
| | | | - Paula M Canas
- Center for Neuroscience and Cell Biology, CNC, Coimbra, Portugal
| | - Rodrigo A Cunha
- Center for Neuroscience and Cell Biology, CNC, Coimbra, Portugal.,Faculty of Medicine, University of Coimbra, FMUC, Coimbra, Portugal
| | - Paula Agostinho
- Center for Neuroscience and Cell Biology, CNC, Coimbra, Portugal.,Faculty of Medicine, University of Coimbra, FMUC, Coimbra, Portugal
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169
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Hart CG, Karimi-Abdolrezaee S. Recent insights on astrocyte mechanisms in CNS homeostasis, pathology, and repair. J Neurosci Res 2021; 99:2427-2462. [PMID: 34259342 DOI: 10.1002/jnr.24922] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2021] [Revised: 06/06/2021] [Accepted: 06/24/2021] [Indexed: 12/20/2022]
Abstract
Astrocytes play essential roles in development, homeostasis, injury, and repair of the central nervous system (CNS). Their development is tightly regulated by distinct spatial and temporal cues during embryogenesis and into adulthood throughout the CNS. Astrocytes have several important responsibilities such as regulating blood flow and permeability of the blood-CNS barrier, glucose metabolism and storage, synapse formation and function, and axon myelination. In CNS pathologies, astrocytes also play critical parts in both injury and repair mechanisms. Upon injury, they undergo a robust phenotypic shift known as "reactive astrogliosis," which results in both constructive and deleterious outcomes. Astrocyte activation and migration at the site of injury provides an early defense mechanism to minimize the extent of injury by enveloping the lesion area. However, astrogliosis also contributes to the inhibitory microenvironment of CNS injury and potentiate secondary injury mechanisms, such as inflammation, oxidative stress, and glutamate excitotoxicity, which facilitate neurodegeneration in CNS pathologies. Intriguingly, reactive astrocytes are increasingly a focus in current therapeutic strategies as their activation can be modulated toward a neuroprotective and reparative phenotype. This review will discuss recent advancements in knowledge regarding the development and role of astrocytes in the healthy and pathological CNS. We will also review how astrocytes have been genetically modified to optimize their reparative potential after injury, and how they may be transdifferentiated into neurons and oligodendrocytes to promote repair after CNS injury and neurodegeneration.
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Affiliation(s)
- Christopher G Hart
- Department of Physiology and Pathophysiology, Spinal Cord Research Centre, Children's Hospital Research Institute of Manitoba, University of Manitoba, Winnipeg, MB, Canada
| | - Soheila Karimi-Abdolrezaee
- Department of Physiology and Pathophysiology, Spinal Cord Research Centre, Children's Hospital Research Institute of Manitoba, University of Manitoba, Winnipeg, MB, Canada
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170
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Integrative Functional Genomic Analysis of Molecular Signatures and Mechanistic Pathways in the Cell Cycle Underlying Alzheimer's Disease. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2021; 2021:5552623. [PMID: 34336099 PMCID: PMC8290224 DOI: 10.1155/2021/5552623] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/27/2021] [Accepted: 06/25/2021] [Indexed: 11/18/2022]
Abstract
Objective Alzheimer's disease (AD) is associated with cell cycle reentry of mature neurons that subsequently undergo degeneration. This study is aimed to identify key regulators of the cell cycle and their underlying pathways for developing optimal treatment of AD. Methods RNA sequencing data were profiled to screen for differentially expressed genes in the cell cycle. Correlation of created modules with AD phenotype was computed by weight gene correlation network analysis (WGCNA). Signature genes for trophic factor receptors were determined using Pearson correlation coefficient (PCC) analysis. Results Among the 13,679 background genes, 775 cell cycle genes and 77 trophic factor receptors were differentially expressed in AD versus nondementia controls. Four coexpression modules were constructed by WGCNA, among which the turquoise module had the strongest correlation with AD. According to PCC analysis, 10 signature trophic receptors most strongly interacting with cell cycle genes were filtered and subsequently displayed in the global regulatory network. Further cross-talking pathways of signature receptors, such as glutamatergic synapse, long-term potentiation, PI3K-Akt, and MAPK signaling pathways, were identified. Conclusions Our findings highlighted the mechanistic pathways of signature trophic receptors in cell cycle perturbation underlying AD pathogenesis, thereby providing new molecular targets for therapeutic intervention in AD.
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171
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Sherwood MW, Oliet SHR, Panatier A. NMDARs, Coincidence Detectors of Astrocytic and Neuronal Activities. Int J Mol Sci 2021; 22:7258. [PMID: 34298875 PMCID: PMC8307462 DOI: 10.3390/ijms22147258] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Revised: 06/30/2021] [Accepted: 06/30/2021] [Indexed: 12/18/2022] Open
Abstract
Synaptic plasticity is an extensively studied cellular correlate of learning and memory in which NMDARs play a starring role. One of the most interesting features of NMDARs is their ability to act as a co-incident detector. It is unique amongst neurotransmitter receptors in this respect. Co-incident detection is possible because the opening of NMDARs requires membrane depolarisation and the binding of glutamate. Opening of NMDARs also requires a co-agonist. Although the dynamic regulation of glutamate and membrane depolarization have been well studied in coincident detection, the role of the co-agonist site is unexplored. It turns out that non-neuronal glial cells, astrocytes, regulate co-agonist availability, giving them the ability to influence synaptic plasticity. The unique morphology and spatial arrangement of astrocytes at the synaptic level affords them the capacity to sample and integrate information originating from unrelated synapses, regardless of any pre-synaptic and post-synaptic commonality. As astrocytes are classically considered slow responders, their influence at the synapse is widely recognized as modulatory. The aim herein is to reconsider the potential of astrocytes to participate directly in ongoing synaptic NMDAR activity and co-incident detection.
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Affiliation(s)
- Mark W. Sherwood
- University of Bordeaux, INSERM, Neurocentre Magendie, U1215, F-3300 Bordeaux, France;
| | | | - Aude Panatier
- University of Bordeaux, INSERM, Neurocentre Magendie, U1215, F-3300 Bordeaux, France;
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172
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Ma Z, Wei L, Du X, Hou S, Chen F, Jiao Q, Liu A, Liu S, Wang J, Shen H. Two-photon calcium imaging of neuronal and astrocytic responses: the influence of electrical stimulus parameters and calcium signaling mechanisms. J Neural Eng 2021; 18. [PMID: 34130271 DOI: 10.1088/1741-2552/ac0b50] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Accepted: 06/15/2021] [Indexed: 12/30/2022]
Abstract
Objective. Electrical brain stimulation has been used to ameliorate symptoms associated with neurologic and psychiatric disorders. The astrocytic activation and its interaction with neurons may contribute to the therapeutic effects of electrical stimulation. However, how the astrocytic activity is affected by electrical stimulation and its calcium signaling mechanisms remain largely unknown. This study is to explore the influence of electrical stimulus parameters on cellular calcium responses and corresponding calcium signaling mechanisms, with a focus on the heretofore largely overlooked astrocytes.Approach. Usingin vivotwo-photon microscopy in mouse somatosensory cortex, the calcium activity in neurons and astrocytes were recorded.Main results. The cathodal stimulation evoked larger responses in both neurons and astrocytes than anodal stimulation. Both neuronal and astrocytic response profiles exhibited the unimodal frequency dependency, the astrocytes prefer higher frequency stimulation than neurons. Astrocytes need longer pulse width and higher current intensity than neurons to activate. Compared to neurons, the astrocytes were not capable of keeping sustained calcium elevation during prolonged electrical stimulation. The neuronal Ca2+influx involves postsynaptic effects and direct depolarization. The Ca2+surge of astrocytes has a neuronal origin, the noradrenergic and glutamatergic signaling act synergistically to induce astrocytic activity.Significance. The astrocytic activity can be regulated by manipulating stimulus parameters and its calcium activation should be fully considered when interpreting the mechanisms of action of electrical neuromodulation. This study brings considerable benefits in the application of electrical stimulation and provides useful insights into cortical signal transduction, which contributes to the understanding of mechanisms underlying the therapeutic efficacy of electrical stimulation for neurorehabilitation applications.
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Affiliation(s)
- Zengguang Ma
- School of Biomedical Engineering, Tianjin Medical University, 22 Qixiangtai Road, Tianjin 300070, China
| | - Liangpeng Wei
- School of Biomedical Engineering, Tianjin Medical University, 22 Qixiangtai Road, Tianjin 300070, China
| | - Xiaolang Du
- Department of Pharmacy, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin's Clinical Research Center for Cancer, Tianjin 300060, China
| | - Shaowei Hou
- School of Biomedical Engineering, Tianjin Medical University, 22 Qixiangtai Road, Tianjin 300070, China
| | - Feng Chen
- School of Biomedical Engineering, Tianjin Medical University, 22 Qixiangtai Road, Tianjin 300070, China
| | - Qingyan Jiao
- School of Biomedical Engineering, Tianjin Medical University, 22 Qixiangtai Road, Tianjin 300070, China
| | - Aili Liu
- School of Biomedical Engineering, Tianjin Medical University, 22 Qixiangtai Road, Tianjin 300070, China
| | - Shujing Liu
- School of Biomedical Engineering, Tianjin Medical University, 22 Qixiangtai Road, Tianjin 300070, China
| | - Junsong Wang
- School of Biomedical Engineering, Tianjin Medical University, 22 Qixiangtai Road, Tianjin 300070, China
| | - Hui Shen
- School of Biomedical Engineering, Tianjin Medical University, 22 Qixiangtai Road, Tianjin 300070, China.,Research Institute of Neurology, General Hospital, Tianjin Medical University, Tianjin 300052, China
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Goodman AM, Langner BM, Jackson N, Alex C, McMahon LL. Heightened Hippocampal β-Adrenergic Receptor Function Drives Synaptic Potentiation and Supports Learning and Memory in the TgF344-AD Rat Model during Prodromal Alzheimer's Disease. J Neurosci 2021; 41:5747-5761. [PMID: 33952633 PMCID: PMC8244969 DOI: 10.1523/jneurosci.0119-21.2021] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2021] [Revised: 02/23/2021] [Accepted: 04/28/2021] [Indexed: 01/27/2023] Open
Abstract
The central noradrenergic (NA) system is critical for the maintenance of attention, behavioral flexibility, spatial navigation, and learning and memory, those cognitive functions lost first in early Alzheimer's disease (AD). In fact, the locus coeruleus (LC), the sole source of norepinephrine (NE) for >90% of the brain, is the first site of pathologic tau accumulation in human AD with axon loss throughout forebrain, including hippocampus. The dentate gyrus is heavily innervated by LC-NA axons, where released NE acts on β-adrenergic receptors (ARs) at excitatory synapses from entorhinal cortex to facilitate long-term synaptic plasticity and memory formation. These synapses experience dysfunction in early AD before cognitive impairment. In the TgF344-AD rat model of AD, degeneration of LC-NA axons in hippocampus recapitulates human AD, providing a preclinical model to investigate synaptic and behavioral consequences. Using immunohistochemistry, Western blot analysis, and brain slice electrophysiology in 6- to 9-month-old wild-type and TgF344-AD rats, we discovered that the loss of LC-NA axons coincides with the heightened β-AR function at medial perforant path-dentate granule cell synapses that is responsible for the increase in LTP magnitude at these synapses. Furthermore, novel object recognition is facilitated in TgF344-AD rats that requires β-ARs, and pharmacological blockade of β-ARs unmasks a deficit in extinction learning only in TgF344-AD rats, indicating a greater reliance on β-ARs in both behaviors. Thus, a compensatory increase in β-AR function during prodromal AD in TgF344-AD rats heightens synaptic plasticity and preserves some forms of learning and memory.SIGNIFICANCE STATEMENT The locus coeruleus (LC), a brain region located in the brainstem which is responsible for attention and arousal, is damaged first by Alzheimer's disease (AD) pathology. The LC sends axons to hippocampus where released norepinephrine (NE) modulates synaptic function required for learning and memory. How degeneration of LC axons and loss of NE in hippocampus in early AD impacts synaptic function and learning and memory is not well understood despite the importance of LC in cognitive function. We used a transgenic AD rat model with LC axon degeneration mimicking human AD and found that heightened function of β-adrenergic receptors in the dentate gyrus increased synaptic plasticity and preserved learning and memory in early stages of the disease.
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Affiliation(s)
- Anthoni M Goodman
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama 35294-0006
| | - Bethany M Langner
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama 35294-0006
| | - Nateka Jackson
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama 35294-0006
| | - Capri Alex
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama 35294-0006
| | - Lori L McMahon
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama 35294-0006
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174
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Semyachkina-Glushkovskaya O, Mamedova A, Vinnik V, Klimova M, Saranceva E, Ageev V, Yu T, Zhu D, Penzel T, Kurths J. Brain Mechanisms of COVID-19-Sleep Disorders. Int J Mol Sci 2021; 22:6917. [PMID: 34203143 PMCID: PMC8268116 DOI: 10.3390/ijms22136917] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Revised: 06/15/2021] [Accepted: 06/17/2021] [Indexed: 02/06/2023] Open
Abstract
2020 and 2021 have been unprecedented years due to the rapid spread of the modified severe acute respiratory syndrome coronavirus around the world. The coronavirus disease 2019 (COVID-19) causes atypical infiltrated pneumonia with many neurological symptoms, and major sleep changes. The exposure of people to stress, such as social confinement and changes in daily routines, is accompanied by various sleep disturbances, known as 'coronasomnia' phenomenon. Sleep disorders induce neuroinflammation, which promotes the blood-brain barrier (BBB) disruption and entry of antigens and inflammatory factors into the brain. Here, we review findings and trends in sleep research in 2020-2021, demonstrating how COVID-19 and sleep disorders can induce BBB leakage via neuroinflammation, which might contribute to the 'coronasomnia' phenomenon. The new studies suggest that the control of sleep hygiene and quality should be incorporated into the rehabilitation of COVID-19 patients. We also discuss perspective strategies for the prevention of COVID-19-related BBB disorders. We demonstrate that sleep might be a novel biomarker of BBB leakage, and the analysis of sleep EEG patterns can be a breakthrough non-invasive technology for diagnosis of the COVID-19-caused BBB disruption.
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Affiliation(s)
- Oxana Semyachkina-Glushkovskaya
- Institute of Physics, Humboldt University, Newtonstrasse 15, 12489 Berlin, Germany;
- Department of Biology, Saratov State University, Atrakhanskaya Str. 83, 410012 Saratov, Russia; (A.M.); (V.V.); (M.K.); (E.S.); (V.A.)
| | - Aysel Mamedova
- Department of Biology, Saratov State University, Atrakhanskaya Str. 83, 410012 Saratov, Russia; (A.M.); (V.V.); (M.K.); (E.S.); (V.A.)
| | - Valeria Vinnik
- Department of Biology, Saratov State University, Atrakhanskaya Str. 83, 410012 Saratov, Russia; (A.M.); (V.V.); (M.K.); (E.S.); (V.A.)
| | - Maria Klimova
- Department of Biology, Saratov State University, Atrakhanskaya Str. 83, 410012 Saratov, Russia; (A.M.); (V.V.); (M.K.); (E.S.); (V.A.)
| | - Elena Saranceva
- Department of Biology, Saratov State University, Atrakhanskaya Str. 83, 410012 Saratov, Russia; (A.M.); (V.V.); (M.K.); (E.S.); (V.A.)
| | - Vasily Ageev
- Department of Biology, Saratov State University, Atrakhanskaya Str. 83, 410012 Saratov, Russia; (A.M.); (V.V.); (M.K.); (E.S.); (V.A.)
| | - Tingting Yu
- Wuhan National Laboratory for Optoelectronics, Britton Chance Center for Biomedical Photonics, Huazhong University of Science and Technology, Wuhan 430074, China; (T.Y.); (D.Z.)
- MoE Key Laboratory for Biomedical Photonics, Collaborative Innovation Center for Biomedical Engineering, School of Engineering Sciences, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Dan Zhu
- Wuhan National Laboratory for Optoelectronics, Britton Chance Center for Biomedical Photonics, Huazhong University of Science and Technology, Wuhan 430074, China; (T.Y.); (D.Z.)
- MoE Key Laboratory for Biomedical Photonics, Collaborative Innovation Center for Biomedical Engineering, School of Engineering Sciences, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Thomas Penzel
- Department of Biology, Saratov State University, Atrakhanskaya Str. 83, 410012 Saratov, Russia; (A.M.); (V.V.); (M.K.); (E.S.); (V.A.)
- Sleep Medicine Center, Charité-Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany
| | - Jürgen Kurths
- Institute of Physics, Humboldt University, Newtonstrasse 15, 12489 Berlin, Germany;
- Department of Biology, Saratov State University, Atrakhanskaya Str. 83, 410012 Saratov, Russia; (A.M.); (V.V.); (M.K.); (E.S.); (V.A.)
- Potsdam Institute for Climate Impact Research, Telegrafenberg A31, 14473 Potsdam, Germany
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175
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Pollegioni L, Molla G, Sacchi S, Murtas G. Human D-aspartate Oxidase: A Key Player in D-aspartate Metabolism. Front Mol Biosci 2021; 8:689719. [PMID: 34250021 PMCID: PMC8260693 DOI: 10.3389/fmolb.2021.689719] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Accepted: 06/09/2021] [Indexed: 11/15/2022] Open
Abstract
In recent years, the D-enantiomers of amino acids have been recognized as natural molecules present in all kingdoms, playing a variety of biological roles. In humans, d-serine and d-aspartate attracted attention for their presence in the central nervous system. Here, we focus on d-aspartate, which is involved in glutamatergic neurotransmission and the synthesis of various hormones. The biosynthesis of d-aspartate is still obscure, while its degradation is due to the peroxisomal flavin adenine dinucleotide (FAD)-containing enzyme d-aspartate oxidase. d-Aspartate emergence is strictly controlled: levels decrease in brain within the first days of life while increasing in endocrine glands postnatally and through adulthood. The human d-aspartate oxidase (hDASPO) belongs to the d-amino acid oxidase-like family: its tertiary structure closely resembles that of human d-amino acid oxidase (hDAAO), the enzyme that degrades neutral and basic d-amino acids. The structure-function relationships of the physiological isoform of hDASPO (named hDASPO_341) and the regulation of gene expression and distribution and properties of the longer isoform hDASPO_369 have all been recently elucidated. Beyond the substrate preference, hDASPO and hDAAO also differ in kinetic efficiency, FAD-binding affinity, pH profile, and oligomeric state. Such differences suggest that evolution diverged to create two different ways to modulate d-aspartate and d-serine levels in the human brain. Current knowledge about hDASPO is shedding light on the molecular mechanisms underlying the modulation of d-aspartate levels in human tissues and is pushing novel, targeted therapeutic strategies. Now, it has been proposed that dysfunction in NMDA receptor-mediated neurotransmission is caused by disrupted d-aspartate metabolism in the nervous system during the onset of various disorders (such as schizophrenia): the design of suitable hDASPO inhibitors aimed at increasing d-aspartate levels thus represents a novel and useful form of therapy.
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Affiliation(s)
- Loredano Pollegioni
- Department of Biotechnology and Life Sciences, University of Insubria, Varese, Italy
| | - Gianluca Molla
- Department of Biotechnology and Life Sciences, University of Insubria, Varese, Italy
| | - Silvia Sacchi
- Department of Biotechnology and Life Sciences, University of Insubria, Varese, Italy
| | - Giulia Murtas
- Department of Biotechnology and Life Sciences, University of Insubria, Varese, Italy
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176
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Covelo A, Eraso-Pichot A, Fernández-Moncada I, Serrat R, Marsicano G. CB1R-dependent regulation of astrocyte physiology and astrocyte-neuron interactions. Neuropharmacology 2021; 195:108678. [PMID: 34157362 DOI: 10.1016/j.neuropharm.2021.108678] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 05/24/2021] [Accepted: 06/17/2021] [Indexed: 12/12/2022]
Abstract
The endocannabinoid system (ECS) is involved in a variety of brain functions, mainly through the activation of the type-1 cannabinoid receptors (CB1R). CB1R are highly expressed throughout the brain at different structural, cellular and subcellular locations and its activity and expression levels have a direct impact in synaptic activity and behavior. In the last few decades, astrocytes have arisen as active players of brain physiology through their participation in the tripartite synapse and through their metabolic interaction with neurons. Here, we discuss some of the mechanisms by which astroglial CB1R at different subcellular locations, regulate astrocyte calcium signals and have an impact on gliotransmission and metabolic regulation. In addition, we discuss evidence pointing at astrocytes as potential important sources of endocannabinoid synthesis and release. Thus, we summarize recent findings that add further complexity and establish that the ECS is a fundamental effector of astrocyte functions in the brain. This article is part of the special issue on 'Cannabinoids'.
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Affiliation(s)
- Ana Covelo
- Institut national de la santé et de la recherche médicale (INSERM), U1215 NeuroCentre Magendie, Bordeaux, 33077, France; University of Bordeaux, Bordeaux, 33077, France
| | - Abel Eraso-Pichot
- Institut national de la santé et de la recherche médicale (INSERM), U1215 NeuroCentre Magendie, Bordeaux, 33077, France; University of Bordeaux, Bordeaux, 33077, France
| | - Ignacio Fernández-Moncada
- Institut national de la santé et de la recherche médicale (INSERM), U1215 NeuroCentre Magendie, Bordeaux, 33077, France; University of Bordeaux, Bordeaux, 33077, France
| | - Román Serrat
- Institut national de la santé et de la recherche médicale (INSERM), U1215 NeuroCentre Magendie, Bordeaux, 33077, France; University of Bordeaux, Bordeaux, 33077, France; INRAE, Nutrition and Integrative Neurobiology, UMR 1286, 33077, Bordeaux, France
| | - Giovanni Marsicano
- Institut national de la santé et de la recherche médicale (INSERM), U1215 NeuroCentre Magendie, Bordeaux, 33077, France; University of Bordeaux, Bordeaux, 33077, France.
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177
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Maugeri G, D’Agata V, Magrì B, Roggio F, Castorina A, Ravalli S, Di Rosa M, Musumeci G. Neuroprotective Effects of Physical Activity via the Adaptation of Astrocytes. Cells 2021; 10:cells10061542. [PMID: 34207393 PMCID: PMC8234474 DOI: 10.3390/cells10061542] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Revised: 06/14/2021] [Accepted: 06/14/2021] [Indexed: 12/27/2022] Open
Abstract
The multifold benefits of regular physical exercise have been largely demonstrated in human and animal models. Several studies have reported the beneficial effects of physical activity, both in peripheral tissues and in the central nervous system (CNS). Regular exercise improves cognition, brain plasticity, neurogenesis and reduces the symptoms of neurodegenerative diseases, making timeless the principle of “mens sana in corpore sano” (i.e., a healthy mind in a healthy body). Physical exercise promotes morphological and functional changes in the brain, acting not only in neurons but also in astrocytes, which represent the most numerous glial cells in the brain. The multiple effects of exercise on astrocytes comprise the increased number of new astrocytes, the maintenance of basal levels of catecholamine, the increase in glutamate uptake, the major release of trophic factors and better astrocytic coverage of cerebral blood vessels. The purpose of this review is to highlight the effects of exercise on brain function, emphasize the role of astrocytes in the healthy CNS, and provide an update for a better understanding of the effects of physical exercise in the modulation of astrocyte function.
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Affiliation(s)
- Grazia Maugeri
- Department of Biomedical and Biotechnological Sciences, Human, Histology and Movement Science Section, University of Catania, Via S. Sofia n°87, 95100 Catania, Italy; (G.M.); (V.D.); (B.M.); (F.R.); (S.R.); (M.D.R.)
| | - Velia D’Agata
- Department of Biomedical and Biotechnological Sciences, Human, Histology and Movement Science Section, University of Catania, Via S. Sofia n°87, 95100 Catania, Italy; (G.M.); (V.D.); (B.M.); (F.R.); (S.R.); (M.D.R.)
| | - Benedetta Magrì
- Department of Biomedical and Biotechnological Sciences, Human, Histology and Movement Science Section, University of Catania, Via S. Sofia n°87, 95100 Catania, Italy; (G.M.); (V.D.); (B.M.); (F.R.); (S.R.); (M.D.R.)
| | - Federico Roggio
- Department of Biomedical and Biotechnological Sciences, Human, Histology and Movement Science Section, University of Catania, Via S. Sofia n°87, 95100 Catania, Italy; (G.M.); (V.D.); (B.M.); (F.R.); (S.R.); (M.D.R.)
| | - Alessandro Castorina
- Laboratory of Cellular and Molecular Neuroscience (LCMN), School of Life Science, Faculty of Science, University of Technology Sydney, Broadway, NSW 2007, Australia;
- Laboratory of Neural Structure and Function (LNSF), School of Medical Sciences, (Anatomy and Histology), Faculty of Medicine and Health, University of Sydney, Sydney, NSW 2006, Australia
| | - Silvia Ravalli
- Department of Biomedical and Biotechnological Sciences, Human, Histology and Movement Science Section, University of Catania, Via S. Sofia n°87, 95100 Catania, Italy; (G.M.); (V.D.); (B.M.); (F.R.); (S.R.); (M.D.R.)
| | - Michelino Di Rosa
- Department of Biomedical and Biotechnological Sciences, Human, Histology and Movement Science Section, University of Catania, Via S. Sofia n°87, 95100 Catania, Italy; (G.M.); (V.D.); (B.M.); (F.R.); (S.R.); (M.D.R.)
| | - Giuseppe Musumeci
- Department of Biomedical and Biotechnological Sciences, Human, Histology and Movement Science Section, University of Catania, Via S. Sofia n°87, 95100 Catania, Italy; (G.M.); (V.D.); (B.M.); (F.R.); (S.R.); (M.D.R.)
- Research Center on Motor Activities (CRAM), University of Catania, Via S. Sofia n°97, 95100 Catania, Italy
- Department of Biology, Sbarro Institute for Cancer Research and Molecular Medicine, College of Science and Technology, Temple University, Philadelphia, PA 19122, USA
- Correspondence: ; Tel.: +39-095-378-2043
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178
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Pérez-Sisqués L, Sancho-Balsells A, Solana-Balaguer J, Campoy-Campos G, Vives-Isern M, Soler-Palazón F, Anglada-Huguet M, López-Toledano MÁ, Mandelkow EM, Alberch J, Giralt A, Malagelada C. RTP801/REDD1 contributes to neuroinflammation severity and memory impairments in Alzheimer's disease. Cell Death Dis 2021; 12:616. [PMID: 34131105 PMCID: PMC8206344 DOI: 10.1038/s41419-021-03899-y] [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: 11/19/2020] [Revised: 05/25/2021] [Accepted: 06/01/2021] [Indexed: 02/05/2023]
Abstract
RTP801/REDD1 is a stress-regulated protein whose upregulation is necessary and sufficient to trigger neuronal death. Its downregulation in Parkinson's and Huntington's disease models ameliorates the pathological phenotypes. In the context of Alzheimer's disease (AD), the coding gene for RTP801, DDIT4, is responsive to Aβ and modulates its cytotoxicity in vitro. Also, RTP801 mRNA levels are increased in AD patients' lymphocytes. However, the involvement of RTP801 in the pathophysiology of AD has not been yet tested. Here, we demonstrate that RTP801 levels are increased in postmortem hippocampal samples from AD patients. Interestingly, RTP801 protein levels correlated with both Braak and Thal stages of the disease and with GFAP expression. RTP801 levels are also upregulated in hippocampal synaptosomal fractions obtained from murine 5xFAD and rTg4510 mice models of the disease. A local RTP801 knockdown in the 5xFAD hippocampal neurons with shRNA-containing AAV particles ameliorates cognitive deficits in 7-month-old animals. Upon RTP801 silencing in the 5xFAD mice, no major changes were detected in hippocampal synaptic markers or spine density. Importantly, we found an unanticipated recovery of several gliosis hallmarks and inflammasome key proteins upon neuronal RTP801 downregulation in the 5xFAD mice. Altogether our results suggest that RTP801 could be a potential future target for theranostic studies since it could be a biomarker of neuroinflammation and neurotoxicity severity of the disease and, at the same time, a promising therapeutic target in the treatment of AD.
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Affiliation(s)
- Leticia Pérez-Sisqués
- Departament de Biomedicina, Facultat de Medicina i Ciències de la Salut, Institut de Neurociències, Universitat de Barcelona, Barcelona, Catalonia, Spain
| | - Anna Sancho-Balsells
- Departament de Biomedicina, Facultat de Medicina i Ciències de la Salut, Institut de Neurociències, Universitat de Barcelona, Barcelona, Catalonia, Spain
- Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Catalonia, Spain
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
| | - Júlia Solana-Balaguer
- Departament de Biomedicina, Facultat de Medicina i Ciències de la Salut, Institut de Neurociències, Universitat de Barcelona, Barcelona, Catalonia, Spain
| | - Genís Campoy-Campos
- Departament de Biomedicina, Facultat de Medicina i Ciències de la Salut, Institut de Neurociències, Universitat de Barcelona, Barcelona, Catalonia, Spain
| | - Marcel Vives-Isern
- Departament de Biomedicina, Facultat de Medicina i Ciències de la Salut, Institut de Neurociències, Universitat de Barcelona, Barcelona, Catalonia, Spain
| | - Ferran Soler-Palazón
- Departament de Biomedicina, Facultat de Medicina i Ciències de la Salut, Institut de Neurociències, Universitat de Barcelona, Barcelona, Catalonia, Spain
| | - Marta Anglada-Huguet
- German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany
- CAESAR Research Center, Bonn, Germany
| | | | - Eva-Maria Mandelkow
- German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany
- CAESAR Research Center, Bonn, Germany
| | - Jordi Alberch
- Departament de Biomedicina, Facultat de Medicina i Ciències de la Salut, Institut de Neurociències, Universitat de Barcelona, Barcelona, Catalonia, Spain
- Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Catalonia, Spain
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
- Production and Validation Center of Advanced Therapies (Creatio), Faculty of Medicine and Health Science, University of Barcelona, Barcelona, Catalonia, Spain
| | - Albert Giralt
- Departament de Biomedicina, Facultat de Medicina i Ciències de la Salut, Institut de Neurociències, Universitat de Barcelona, Barcelona, Catalonia, Spain.
- Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Catalonia, Spain.
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain.
- Production and Validation Center of Advanced Therapies (Creatio), Faculty of Medicine and Health Science, University of Barcelona, Barcelona, Catalonia, Spain.
| | - Cristina Malagelada
- Departament de Biomedicina, Facultat de Medicina i Ciències de la Salut, Institut de Neurociències, Universitat de Barcelona, Barcelona, Catalonia, Spain.
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain.
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179
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Refaeli R, Doron A, Benmelech-Chovav A, Groysman M, Kreisel T, Loewenstein Y, Goshen I. Features of hippocampal astrocytic domains and their spatial relation to excitatory and inhibitory neurons. Glia 2021; 69:2378-2390. [PMID: 34117643 DOI: 10.1002/glia.24044] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Revised: 05/28/2021] [Accepted: 06/01/2021] [Indexed: 11/07/2022]
Abstract
The mounting evidence for the involvement of astrocytes in neuronal circuits function and behavior stands in stark contrast to the lack of detailed anatomical description of these cells and the neurons in their domains. To fill this void, we imaged >30,000 astrocytes in hippocampi made transparent by CLARITY, and determined the elaborate structure, distribution, and neuronal content of astrocytic domains. First, we characterized the spatial distribution of >19,000 astrocytes across CA1 lamina, and analyzed the morphology of thousands of reconstructed domains. We then determined the excitatory somatic content of CA1 astrocytes, and measured the distance between inhibitory neuronal somata to the nearest astrocyte soma. We find that on average, there are almost 14 pyramidal neurons per domain in the CA1, increasing toward the pyramidal layer midline, compared to only five excitatory neurons per domain in the amygdala. Finally, we discovered that somatostatin neurons are found in close proximity to astrocytes, compared to parvalbumin and VIP inhibitory neurons. This work provides a comprehensive large-scale quantitative foundation for studying neuron-astrocyte interactions.
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Affiliation(s)
- Ron Refaeli
- Edmond and Lily Safra Center for Brain Sciences (ELSC), The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Adi Doron
- Edmond and Lily Safra Center for Brain Sciences (ELSC), The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Aviya Benmelech-Chovav
- Edmond and Lily Safra Center for Brain Sciences (ELSC), The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Maya Groysman
- ELSC Vector Core Facility, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Tirzah Kreisel
- Edmond and Lily Safra Center for Brain Sciences (ELSC), The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Yonatan Loewenstein
- Edmond and Lily Safra Center for Brain Sciences (ELSC), The Hebrew University of Jerusalem, Jerusalem, Israel.,Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel.,Federmann Center for the Study of Rationality, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Inbal Goshen
- Edmond and Lily Safra Center for Brain Sciences (ELSC), The Hebrew University of Jerusalem, Jerusalem, Israel
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180
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Lohr C, Beiersdorfer A, Fischer T, Hirnet D, Rotermund N, Sauer J, Schulz K, Gee CE. Using Genetically Encoded Calcium Indicators to Study Astrocyte Physiology: A Field Guide. Front Cell Neurosci 2021; 15:690147. [PMID: 34177468 PMCID: PMC8226001 DOI: 10.3389/fncel.2021.690147] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Accepted: 05/06/2021] [Indexed: 01/14/2023] Open
Abstract
Ca2+ imaging is the most frequently used technique to study glial cell physiology. While chemical Ca2+ indicators served to visualize and measure changes in glial cell cytosolic Ca2+ concentration for several decades, genetically encoded Ca2+ indicators (GECIs) have become state of the art in recent years. Great improvements have been made since the development of the first GECI and a large number of GECIs with different physical properties exist, rendering it difficult to select the optimal Ca2+ indicator. This review discusses some of the most frequently used GECIs and their suitability for glial cell research.
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Affiliation(s)
- Christian Lohr
- Division of Neurophysiology, University of Hamburg, Hamburg, Germany
| | | | - Timo Fischer
- Division of Neurophysiology, University of Hamburg, Hamburg, Germany
| | - Daniela Hirnet
- Division of Neurophysiology, University of Hamburg, Hamburg, Germany
| | - Natalie Rotermund
- Division of Neurophysiology, University of Hamburg, Hamburg, Germany
| | - Jessica Sauer
- Division of Neurophysiology, University of Hamburg, Hamburg, Germany
| | - Kristina Schulz
- Division of Neurophysiology, University of Hamburg, Hamburg, Germany
| | - Christine E Gee
- Institute of Synaptic Physiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
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181
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Lia A, Henriques VJ, Zonta M, Chiavegato A, Carmignoto G, Gómez-Gonzalo M, Losi G. Calcium Signals in Astrocyte Microdomains, a Decade of Great Advances. Front Cell Neurosci 2021; 15:673433. [PMID: 34163329 PMCID: PMC8216559 DOI: 10.3389/fncel.2021.673433] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2021] [Accepted: 04/23/2021] [Indexed: 12/13/2022] Open
Abstract
The glial cells astrocytes have long been recognized as important neuron-supporting elements in brain development, homeostasis, and metabolism. After the discovery that the reciprocal communication between astrocytes and neurons is a fundamental mechanism in the modulation of neuronal synaptic communication, over the last two decades astrocytes became a hot topic in neuroscience research. Crucial to their functional interactions with neurons are the cytosolic Ca2+ elevations that mediate gliotransmission. Large attention has been posed to the so-called Ca2+microdomains, dynamic Ca2+ changes spatially restricted to fine astrocytic processes including perisynaptic astrocytic processes (PAPs). With presynaptic terminals and postsynaptic neuronal membranes, PAPs compose the tripartite synapse. The distinct spatial-temporal features and functional roles of astrocyte microdomain Ca2+ activity remain poorly defined. However, thanks to the development of genetically encoded Ca2+ indicators (GECIs), advanced microscopy techniques, and innovative analytical approaches, Ca2+ transients in astrocyte microdomains were recently studied in unprecedented detail. These events have been observed to occur much more frequently (∼50–100-fold) and dynamically than somatic Ca2+ elevations with mechanisms that likely involve both IP3-dependent and -independent pathways. Further progress aimed to clarify the complex, dynamic machinery responsible for astrocytic Ca2+ activity at microdomains is a crucial step in our understanding of the astrocyte role in brain function and may also reveal astrocytes as novel therapeutic targets for different brain diseases. Here, we review the most recent studies that improve our mechanistic understanding of the essential features of astrocyte Ca2+ microdomains.
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Affiliation(s)
- Annamaria Lia
- Neuroscience Institute, National Research Council (IN-CNR), Padua, Italy.,Department of Biomedical Sciences, University of Padua, Padua, Italy
| | - Vanessa Jorge Henriques
- Neuroscience Institute, National Research Council (IN-CNR), Padua, Italy.,Department of Biomedical Sciences, University of Padua, Padua, Italy
| | - Micaela Zonta
- Neuroscience Institute, National Research Council (IN-CNR), Padua, Italy.,Department of Biomedical Sciences, University of Padua, Padua, Italy
| | - Angela Chiavegato
- Department of Biomedical Sciences, University of Padua, Padua, Italy
| | - Giorgio Carmignoto
- Neuroscience Institute, National Research Council (IN-CNR), Padua, Italy.,Department of Biomedical Sciences, University of Padua, Padua, Italy
| | - Marta Gómez-Gonzalo
- Neuroscience Institute, National Research Council (IN-CNR), Padua, Italy.,Department of Biomedical Sciences, University of Padua, Padua, Italy
| | - Gabriele Losi
- Neuroscience Institute, National Research Council (IN-CNR), Padua, Italy.,Department of Biomedical Sciences, University of Padua, Padua, Italy
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182
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Lim EY, Ye L, Paukert M. Potential and Realized Impact of Astroglia Ca 2 + Dynamics on Circuit Function and Behavior. Front Cell Neurosci 2021; 15:682888. [PMID: 34163330 PMCID: PMC8215280 DOI: 10.3389/fncel.2021.682888] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Accepted: 05/03/2021] [Indexed: 11/13/2022] Open
Abstract
Astroglia display a wide range of spontaneous and behavioral state-dependent Ca2+ dynamics. During heightened vigilance, noradrenergic signaling leads to quasi-synchronous Ca2+ elevations encompassing soma and processes across the brain-wide astroglia network. Distinct from this vigilance-associated global Ca2+ rise are apparently spontaneous fluctuations within spatially restricted microdomains. Over the years, several strategies have been pursued to shed light on the physiological impact of these signals including deletion of endogenous ion channels or receptors and reduction of intracellular Ca2+ through buffering, extrusion or inhibition of release. Some experiments that revealed the most compelling behavioral alterations employed chemogenetic and optogenetic manipulations to modify astroglia Ca2+ signaling. However, there is considerable contrast between these findings and the comparatively modest effects of inhibiting endogenous sources of Ca2+. In this review, we describe the underlying mechanisms of various forms of astroglia Ca2+ signaling as well as the functional consequences of their inhibition. We then discuss how the effects of exogenous astroglia Ca2+ modification combined with our knowledge of physiological mechanisms of astroglia Ca2+ activation could guide further refinement of behavioral paradigms that will help elucidate the natural Ca2+-dependent function of astroglia.
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Affiliation(s)
- Eunice Y. Lim
- Department of Cellular and Integrative Physiology, University of Texas Health Science Center at San Antonio, San Antonio, TX, United States,Center for Biomedical Neuroscience, University of Texas Health Science Center at San Antonio, San Antonio, TX, United States
| | - Liang Ye
- Department of Cellular and Integrative Physiology, University of Texas Health Science Center at San Antonio, San Antonio, TX, United States
| | - Martin Paukert
- Department of Cellular and Integrative Physiology, University of Texas Health Science Center at San Antonio, San Antonio, TX, United States,Center for Biomedical Neuroscience, University of Texas Health Science Center at San Antonio, San Antonio, TX, United States,*Correspondence: Martin Paukert,
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183
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Minge D, Domingos C, Unichenko P, Behringer C, Pauletti A, Anders S, Herde MK, Delekate A, Gulakova P, Schoch S, Petzold GC, Henneberger C. Heterogeneity and Development of Fine Astrocyte Morphology Captured by Diffraction-Limited Microscopy. Front Cell Neurosci 2021; 15:669280. [PMID: 34149361 PMCID: PMC8211899 DOI: 10.3389/fncel.2021.669280] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Accepted: 05/06/2021] [Indexed: 12/26/2022] Open
Abstract
The fine processes of single astrocytes can contact many thousands of synapses whose function they can modulate through bi-directional signaling. The spatial arrangement of astrocytic processes and neuronal structures is relevant for such interactions and for the support of neuronal signaling by astrocytes. At the same time, the geometry of perisynaptic astrocyte processes is variable and dynamically regulated. Studying these fine astrocyte processes represents a technical challenge, because many of them cannot be fully resolved by diffraction-limited microscopy. Therefore, we have established two indirect parameters of astrocyte morphology, which, while not fully resolving local geometry by design, provide statistical measures of astrocyte morphology: the fraction of tissue volume that astrocytes occupy and the density of resolvable astrocytic processes. Both are straightforward to obtain using widely available microscopy techniques. We here present the approach and demonstrate its robustness across various experimental conditions using mainly two-photon excitation fluorescence microscopy in acute slices and in vivo as well as modeling. Using these indirect measures allowed us to analyze the morphology of relatively large populations of astrocytes. Doing so we captured the heterogeneity of astrocytes within and between the layers of the hippocampal CA1 region and the developmental profile of astrocyte morphology. This demonstrates that volume fraction (VF) and segment density are useful parameters for describing the structure of astrocytes. They are also suitable for online monitoring of astrocyte morphology with widely available microscopy techniques.
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Affiliation(s)
- Daniel Minge
- Institute of Cellular Neurosciences, Medical Faculty, University of Bonn, Bonn, Germany
| | - Cátia Domingos
- Institute of Cellular Neurosciences, Medical Faculty, University of Bonn, Bonn, Germany
| | - Petr Unichenko
- Institute of Cellular Neurosciences, Medical Faculty, University of Bonn, Bonn, Germany
| | - Charlotte Behringer
- Institute of Cellular Neurosciences, Medical Faculty, University of Bonn, Bonn, Germany
| | - Alberto Pauletti
- Institute of Cellular Neurosciences, Medical Faculty, University of Bonn, Bonn, Germany
| | - Stefanie Anders
- Institute of Cellular Neurosciences, Medical Faculty, University of Bonn, Bonn, Germany
| | - Michel K Herde
- Institute of Cellular Neurosciences, Medical Faculty, University of Bonn, Bonn, Germany
| | - Andrea Delekate
- German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany
| | - Polina Gulakova
- Department of Neuropathology, University Hospital Bonn, Bonn, Germany
| | - Susanne Schoch
- Department of Neuropathology, University Hospital Bonn, Bonn, 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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184
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Maccioni RB, Navarrete LP, González A, González-Canacer A, Guzmán-Martínez L, Cortés N. Inflammation: A Major Target for Compounds to Control Alzheimer's Disease. J Alzheimers Dis 2021; 76:1199-1213. [PMID: 32597798 DOI: 10.3233/jad-191014] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Several hypotheses have been postulated to explain how Alzheimer's disease is triggered, but none of them provide a unified view of its pathogenesis. The dominant hypothesis based on build-ups of the amyloid-β peptide has been around for longer than three decades; however, up to today, numerous clinical trials based on the amyloid postulates have been attempted, but all of them have failed. Clearly, the revisited tau hypothesis provides a better explanation of the clinical observations of patients, but it needs to integrate the cumulative observations on the onset of this disease. In this context, the neuroimmuno modulation theory, based on the involvement of inflammatory events in the central nervous system, accounts for all these observations. In this review we intend to emphasize the idea that neuroinflammation is a main target for the search of new therapeutic strategies to control Alzheimer's disease. Beyond mono-targeting approaches using synthetic drugs that control only specific pathophysiological events, emerging therapeutics views based on multi targeting compounds appear to provide a new pathway for Alzheimer's disease treatment.
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Affiliation(s)
- Ricardo B Maccioni
- Laboratory of Neuroscience and Functional Medicine, International Center for Biomedicine, Vitacura, Santiago, Chile, and Faculty of Sciences, University of Chile, Ñuñoa, Santiago, Chile
| | - Leonardo P Navarrete
- Laboratory of Neuroscience and Functional Medicine, International Center for Biomedicine, Vitacura, Santiago, Chile, and Faculty of Sciences, University of Chile, Ñuñoa, Santiago, Chile
| | - Andrea González
- Laboratory of Neuroscience and Functional Medicine, International Center for Biomedicine, Vitacura, Santiago, Chile, and Faculty of Sciences, University of Chile, Ñuñoa, Santiago, Chile
| | - Alejandra González-Canacer
- Laboratory of Neuroscience and Functional Medicine, International Center for Biomedicine, Vitacura, Santiago, Chile, and Faculty of Sciences, University of Chile, Ñuñoa, Santiago, Chile
| | - Leonardo Guzmán-Martínez
- Laboratory of Neuroscience and Functional Medicine, International Center for Biomedicine, Vitacura, Santiago, Chile, and Faculty of Sciences, University of Chile, Ñuñoa, Santiago, Chile
| | - Nicole Cortés
- Laboratory of Neuroscience and Functional Medicine, International Center for Biomedicine, Vitacura, Santiago, Chile, and Faculty of Sciences, University of Chile, Ñuñoa, Santiago, Chile
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185
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Stavsky A, Stoler O, Kostic M, Katoshevsky T, Assali EA, Savic I, Amitai Y, Prokisch H, Leiz S, Daumer-Haas C, Fleidervish I, Perocchi F, Gitler D, Sekler I. Aberrant activity of mitochondrial NCLX is linked to impaired synaptic transmission and is associated with mental retardation. Commun Biol 2021; 4:666. [PMID: 34079053 PMCID: PMC8172942 DOI: 10.1038/s42003-021-02114-0] [Citation(s) in RCA: 21] [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: 08/25/2020] [Accepted: 03/22/2021] [Indexed: 02/04/2023] Open
Abstract
Calcium dynamics control synaptic transmission. Calcium triggers synaptic vesicle fusion, determines release probability, modulates vesicle recycling, participates in long-term plasticity and regulates cellular metabolism. Mitochondria, the main source of cellular energy, serve as calcium signaling hubs. Mitochondrial calcium transients are primarily determined by the balance between calcium influx, mediated by the mitochondrial calcium uniporter (MCU), and calcium efflux through the sodium/lithium/calcium exchanger (NCLX). We identified a human recessive missense SLC8B1 variant that impairs NCLX activity and is associated with severe mental retardation. On this basis, we examined the effect of deleting NCLX in mice on mitochondrial and synaptic calcium homeostasis, synaptic activity, and plasticity. Neuronal mitochondria exhibited basal calcium overload, membrane depolarization, and a reduction in the amplitude and rate of calcium influx and efflux. We observed smaller cytoplasmic calcium transients in the presynaptic terminals of NCLX-KO neurons, leading to a lower probability of release and weaker transmission. In agreement, synaptic facilitation in NCLX-KO hippocampal slices was enhanced. Importantly, deletion of NCLX abolished long term potentiation of Schaffer collateral synapses. Our results show that NCLX controls presynaptic calcium transients that are crucial for defining synaptic strength as well as short- and long-term plasticity, key elements of learning and memory processes.
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Affiliation(s)
- Alexandra Stavsky
- Department of Physiology and Cell Biology, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
- Zlotowski Center for Neuroscience, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Ohad Stoler
- Department of Physiology and Cell Biology, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
- Zlotowski Center for Neuroscience, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Marko Kostic
- Department of Physiology and Cell Biology, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
- Zlotowski Center for Neuroscience, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Tomer Katoshevsky
- Department of Physiology and Cell Biology, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
- Zlotowski Center for Neuroscience, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Essam A Assali
- Department of Physiology and Cell Biology, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
- Zlotowski Center for Neuroscience, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Ivana Savic
- Department of Physiology and Cell Biology, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
- Zlotowski Center for Neuroscience, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Yael Amitai
- Department of Physiology and Cell Biology, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
- Zlotowski Center for Neuroscience, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Holger Prokisch
- Institute of Human Genetics, School of Medicine, Technische Universität München, Munich, Germany
- Institute of Neurogenomics, Helmholtz Zentrum München, Munich, Germany
| | - Steffen Leiz
- Department of Pediatrics, Klinikum Dritter Orden, Munich, Germany
| | | | - Ilya Fleidervish
- Department of Physiology and Cell Biology, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
- Zlotowski Center for Neuroscience, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Fabiana Perocchi
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center (HDC), Helmholtz Zentrum München, Munich, Germany
- Munich Cluster for Systems Neurology, Munich, Germany
| | - Daniel Gitler
- Department of Physiology and Cell Biology, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel.
- Zlotowski Center for Neuroscience, Ben-Gurion University of the Negev, Beer-Sheva, Israel.
| | - Israel Sekler
- Department of Physiology and Cell Biology, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel.
- Zlotowski Center for Neuroscience, Ben-Gurion University of the Negev, Beer-Sheva, Israel.
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186
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Bouali-Benazzouz R, Landry M, Benazzouz A, Fossat P. Neuropathic pain modeling: Focus on synaptic and ion channel mechanisms. Prog Neurobiol 2021; 201:102030. [PMID: 33711402 DOI: 10.1016/j.pneurobio.2021.102030] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2020] [Accepted: 02/22/2021] [Indexed: 12/28/2022]
Abstract
Animal models of pain consist of modeling a pain-like state and measuring the consequent behavior. The first animal models of neuropathic pain (NP) were developed in rodents with a total lesion of the sciatic nerve. Later, other models targeting central or peripheral branches of nerves were developed to identify novel mechanisms that contribute to persistent pain conditions in NP. Objective assessment of pain in these different animal models represents a significant challenge for pre-clinical research. Multiple behavioral approaches are used to investigate and to validate pain phenotypes including withdrawal reflex to evoked stimuli, vocalizations, spontaneous pain, but also emotional and affective behaviors. Furthermore, animal models were very useful in investigating the mechanisms of NP. This review will focus on a detailed description of rodent models of NP and provide an overview of the assessment of the sensory and emotional components of pain. A detailed inventory will be made to examine spinal mechanisms involved in NP-induced hyperexcitability and underlying the current pharmacological approaches used in clinics with the possibility to present new avenues for future treatment. The success of pre-clinical studies in this area of research depends on the choice of the relevant model and the appropriate test based on the objectives of the study.
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Affiliation(s)
- Rabia Bouali-Benazzouz
- Université de Bordeaux, Institut des Maladies Neurodégénératives, UMR 5293, Bordeaux, France; CNRS, Institut des Maladies Neurodégénératives, UMR 5293, Bordeaux, France.
| | - Marc Landry
- Université de Bordeaux, Institut des Maladies Neurodégénératives, UMR 5293, Bordeaux, France; CNRS, Institut des Maladies Neurodégénératives, UMR 5293, Bordeaux, France
| | - Abdelhamid Benazzouz
- Université de Bordeaux, Institut des Maladies Neurodégénératives, UMR 5293, Bordeaux, France; CNRS, Institut des Maladies Neurodégénératives, UMR 5293, Bordeaux, France
| | - Pascal Fossat
- Université de Bordeaux, Institut des Maladies Neurodégénératives, UMR 5293, Bordeaux, France; CNRS, Institut des Maladies Neurodégénératives, UMR 5293, Bordeaux, France
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187
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Sancho L, Contreras M, Allen NJ. Glia as sculptors of synaptic plasticity. Neurosci Res 2021; 167:17-29. [PMID: 33316304 PMCID: PMC8513541 DOI: 10.1016/j.neures.2020.11.005] [Citation(s) in RCA: 75] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Revised: 11/05/2020] [Accepted: 11/09/2020] [Indexed: 12/16/2022]
Abstract
Glial cells are non-neuronal cells in the nervous system that are crucial for proper brain development and function. Three major classes of glia in the central nervous system (CNS) include astrocytes, microglia and oligodendrocytes. These cells have dynamic morphological and functional properties and constantly surveil neural activity throughout life, sculpting synaptic plasticity. Astrocytes form part of the tripartite synapse with neurons and perform many homeostatic functions essential to proper synaptic function including clearing neurotransmitter and regulating ion balance; they can modify these properties, in addition to additional mechanisms such as gliotransmitter release, to influence short- and long-term plasticity. Microglia, the resident macrophage of the CNS, monitor synaptic activity and can eliminate synapses by phagocytosis or modify synapses by release of cytokines or neurotrophic factors. Oligodendrocytes regulate speed of action potential conduction and efficiency of information exchange through the formation of myelin, having important consequences for the plasticity of neural circuits. A deeper understanding of how glia modulate synaptic and circuit plasticity will further our understanding of the ongoing changes that take place throughout life in the dynamic environment of the CNS.
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Affiliation(s)
- Laura Sancho
- Molecular Neurobiology Laboratory, Salk Institute for Biological Studies, 10010 North Torrey Pines Rd, La Jolla, CA, 92037, USA
| | - Minerva Contreras
- Molecular Neurobiology Laboratory, Salk Institute for Biological Studies, 10010 North Torrey Pines Rd, La Jolla, CA, 92037, USA
| | - Nicola J Allen
- Molecular Neurobiology Laboratory, Salk Institute for Biological Studies, 10010 North Torrey Pines Rd, La Jolla, CA, 92037, USA.
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188
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Jami SA, Cameron S, Wong JM, Daly ER, McAllister AK, Gray JA. Increased excitation-inhibition balance and loss of GABAergic synapses in the serine racemase knockout model of NMDA receptor hypofunction. J Neurophysiol 2021; 126:11-27. [PMID: 34038186 DOI: 10.1152/jn.00661.2020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
There is substantial evidence that both N-methyl-D-aspartate receptor (NMDAR) hypofunction and dysfunction of GABAergic neurotransmission contribute to schizophrenia, though the relationship between these pathophysiological processes remains largely unknown. Although models using cell-type-specific genetic deletion of NMDARs have been informative, they display overly pronounced phenotypes extending beyond those of schizophrenia. Here, we used the serine racemase knockout (SRKO) mice, a model of reduced NMDAR activity rather than complete receptor elimination, to examine the link between NMDAR hypofunction and decreased GABAergic inhibition. The SRKO mice, in which there is a >90% reduction in the NMDAR coagonist d-serine, exhibit many of the neurochemical and behavioral abnormalities observed in schizophrenia. We found a significant reduction in inhibitory synapses onto CA1 pyramidal neurons in the SRKO mice. This reduction increases the excitation/inhibition balance resulting in enhanced synaptically driven neuronal excitability without changes in intrinsic excitability. Consistently, significant reductions in inhibitory synapse density in CA1 were observed by immunohistochemistry. We further show, using a single-neuron genetic deletion approach, that the loss of GABAergic synapses onto pyramidal neurons observed in the SRKO mice is driven in a cell-autonomous manner following the deletion of SR in individual CA1 pyramidal cells. These results support a model whereby NMDAR hypofunction in pyramidal cells disrupts GABAergic synapses leading to disrupted feedback inhibition and impaired neuronal synchrony.NEW & NOTEWORTHY Recently, disruption of excitation/inhibition (E/I) balance has become an area of considerable interest for psychiatric research. Here, we report a reduction in inhibition in the serine racemase knockout mouse model of schizophrenia that increases E/I balance and enhances synaptically driven neuronal excitability. This reduced inhibition was driven cell-autonomously in pyramidal cells lacking serine racemase, suggesting a novel mechanism for how chronic NMDA receptor hypofunction can disrupt information processing in schizophrenia.
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Affiliation(s)
- Shekib A Jami
- Center for Neuroscience, University of California, Davis, California
| | - Scott Cameron
- Center for Neuroscience, University of California, Davis, California
| | - Jonathan M Wong
- Center for Neuroscience, University of California, Davis, California
| | - Emily R Daly
- Center for Neuroscience, University of California, Davis, California
| | - A Kimberley McAllister
- Center for Neuroscience, University of California, Davis, California.,Department of Neurobiology, Physiology, and Behavior, University of California, Davis, California.,Department of Neurology, University of California, Davis, California
| | - John A Gray
- Center for Neuroscience, University of California, Davis, California.,Department of Neurology, University of California, Davis, California
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189
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Chiareli RA, Carvalho GA, Marques BL, Mota LS, Oliveira-Lima OC, Gomes RM, Birbrair A, Gomez RS, Simão F, Klempin F, Leist M, Pinto MCX. The Role of Astrocytes in the Neurorepair Process. Front Cell Dev Biol 2021; 9:665795. [PMID: 34113618 PMCID: PMC8186445 DOI: 10.3389/fcell.2021.665795] [Citation(s) in RCA: 43] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Accepted: 04/29/2021] [Indexed: 12/17/2022] Open
Abstract
Astrocytes are highly specialized glial cells responsible for trophic and metabolic support of neurons. They are associated to ionic homeostasis, the regulation of cerebral blood flow and metabolism, the modulation of synaptic activity by capturing and recycle of neurotransmitters and maintenance of the blood-brain barrier. During injuries and infections, astrocytes act in cerebral defense through heterogeneous and progressive changes in their gene expression, morphology, proliferative capacity, and function, which is known as reactive astrocytes. Thus, reactive astrocytes release several signaling molecules that modulates and contributes to the defense against injuries and infection in the central nervous system. Therefore, deciphering the complex signaling pathways of reactive astrocytes after brain damage can contribute to the neuroinflammation control and reveal new molecular targets to stimulate neurorepair process. In this review, we present the current knowledge about the role of astrocytes in brain damage and repair, highlighting the cellular and molecular bases involved in synaptogenesis and neurogenesis. In addition, we present new approaches to modulate the astrocytic activity and potentiates the neurorepair process after brain damage.
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Affiliation(s)
| | | | | | - Lennia Soares Mota
- Department of Pharmacology, Federal University of Goias, Goiânia, Brazil
| | | | | | - Alexander Birbrair
- Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, Brazil
| | - Renato Santiago Gomez
- Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, Brazil
| | - Fabrício Simão
- Research Division, Vascular Cell Biology, Joslin Diabetes Center and Harvard Medical School, Boston, MA, United States
| | | | - Marcel Leist
- Konstanz Research School Chemical Biology, University of Konstanz, Konstanz, Germany
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190
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McNeill J, Rudyk C, Hildebrand ME, Salmaso N. Ion Channels and Electrophysiological Properties of Astrocytes: Implications for Emergent Stimulation Technologies. Front Cell Neurosci 2021; 15:644126. [PMID: 34093129 PMCID: PMC8173131 DOI: 10.3389/fncel.2021.644126] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2020] [Accepted: 04/26/2021] [Indexed: 12/12/2022] Open
Abstract
Astrocytes comprise a heterogeneous cell population characterized by distinct morphologies, protein expression and function. Unlike neurons, astrocytes do not generate action potentials, however, they are electrically dynamic cells with extensive electrophysiological heterogeneity and diversity. Astrocytes are hyperpolarized cells with low membrane resistance. They are heavily involved in the modulation of K+ and express an array of different voltage-dependent and voltage-independent channels to help with this ion regulation. In addition to these K+ channels, astrocytes also express several different types of Na+ channels; intracellular Na+ signaling in astrocytes has been linked to some of their functional properties. The physiological hallmark of astrocytes is their extensive intracellular Ca2+ signaling cascades, which vary at the regional, subregional, and cellular levels. In this review article, we highlight the physiological properties of astrocytes and the implications for their function and influence of network and synaptic activity. Furthermore, we discuss the implications of these differences in the context of optogenetic and DREADD experiments and consider whether these tools represent physiologically relevant techniques for the interrogation of astrocyte function.
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Affiliation(s)
- Jessica McNeill
- Department of Neuroscience, Carleton University, Ottawa, ON, Canada
| | | | | | - Natalina Salmaso
- Department of Neuroscience, Carleton University, Ottawa, ON, Canada
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191
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Dason JS, Sokolowski MB. A cGMP-dependent protein kinase, encoded by the Drosophila foraging gene, regulates neurotransmission through changes in synaptic structure and function. J Neurogenet 2021; 35:213-220. [PMID: 33998378 DOI: 10.1080/01677063.2021.1905639] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
A cGMP-dependent protein kinase (PKG) encoded by the Drosophila foraging (for) gene regulates both synaptic structure (nerve terminal growth) and function (neurotransmission) through independent mechanisms at the Drosophila larval neuromuscular junction (nmj). Glial for is known to restrict nerve terminal growth, whereas presynaptic for inhibits synaptic vesicle (SV) exocytosis during low frequency stimulation. Presynaptic for also facilitates SV endocytosis during high frequency stimulation. for's effects on neurotransmission can occur independent of any changes in nerve terminal growth. However, it remains unclear if for's effects on neurotransmission affect nerve terminal growth. Furthermore, it's possible that for's effects on synaptic structure contribute to changes in neurotransmission. In the present study, we examined these questions using RNA interference to selectively knockdown for in presynaptic neurons or glia at the Drosophila larval nmj. Consistent with our previous findings, presynaptic knockdown of for impaired SV endocytosis, whereas knockdown of glial for had no effect on SV endocytosis. Surprisingly, we found that knockdown of either presynaptic or glial for increased neurotransmitter release in response to low frequency stimulation. Knockdown of presynaptic for did not affect nerve terminal growth, demonstrating that for's effects on neurotransmission does not alter nerve terminal growth. In contrast, knockdown of glial for enhanced nerve terminal growth. This enhanced nerve terminal growth was likely the cause of the enhanced neurotransmitter release seen following knockdown of glial for. Overall, we show that for can affect neurotransmitter release by regulating both synaptic structure and function.
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Affiliation(s)
- Jeffrey S Dason
- Department of Cell & Systems Biology, University of Toronto, Toronto, Canada.,Department of Biomedical Sciences, University of Windsor, Windsor, Canada
| | - Marla B Sokolowski
- Department of Cell & Systems Biology, University of Toronto, Toronto, Canada.,Department of Ecology & Evolutionary Biology, University of Toronto, Toronto, Canada.,Child and Brain Development Program, Canadian Institute for Advanced Research (CIFAR), Toronto, Canada
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192
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Nosi D, Lana D, Giovannini MG, Delfino G, Zecchi-Orlandini S. Neuroinflammation: Integrated Nervous Tissue Response through Intercellular Interactions at the "Whole System" Scale. Cells 2021; 10:1195. [PMID: 34068375 PMCID: PMC8153304 DOI: 10.3390/cells10051195] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 05/07/2021] [Accepted: 05/10/2021] [Indexed: 12/12/2022] Open
Abstract
Different cell populations in the nervous tissue establish numerous, heterotypic interactions and perform specific, frequently intersecting activities devoted to the maintenance of homeostasis. Microglia and astrocytes, respectively the immune and the "housekeeper" cells of nervous tissue, play a key role in neurodegenerative diseases. Alterations of tissue homeostasis trigger neuroinflammation, a collective dynamic response of glial cells. Reactive astrocytes and microglia express various functional phenotypes, ranging from anti-inflammatory to pro-inflammatory. Chronic neuroinflammation is characterized by a gradual shift of astroglial and microglial phenotypes from anti-inflammatory to pro-inflammatory, switching their activities from cytoprotective to cytotoxic. In this scenario, the different cell populations reciprocally modulate their phenotypes through intense, reverberating signaling. Current evidence suggests that heterotypic interactions are links in an intricate network of mutual influences and interdependencies connecting all cell types in the nervous system. In this view, activation, modulation, as well as outcomes of neuroinflammation, should be ascribed to the nervous tissue as a whole. While the need remains of identifying further links in this network, a step back to rethink our view of neuroinflammation in the light of the "whole system" scale, could help us to understand some of its most controversial and puzzling features.
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Affiliation(s)
- Daniele Nosi
- Section of Histology anf Human Anatomy, Department of Experimental and Clinical Medicine, University of Florence, Largo Brambilla, 3, 50134 Florence, Italy;
| | - Daniele Lana
- Section of Clinical Pharmacology and Oncology, Department of Health Sciences, University of Florence, Viale Gaetano Pieraccini, 50139 Florence, Italy; (D.L.); (M.G.G.)
| | - Maria Grazia Giovannini
- Section of Clinical Pharmacology and Oncology, Department of Health Sciences, University of Florence, Viale Gaetano Pieraccini, 50139 Florence, Italy; (D.L.); (M.G.G.)
| | - Giovanni Delfino
- Department of Biology, University of Florence, Via Madonna del Piano, 6, 50019 Sesto Fiorentino, Florence, Italy;
| | - Sandra Zecchi-Orlandini
- Section of Histology anf Human Anatomy, Department of Experimental and Clinical Medicine, University of Florence, Largo Brambilla, 3, 50134 Florence, Italy;
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193
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De-Miguel FF, Leon-Pinzon C, Torres-Platas SG, Del-Pozo V, Hernández-Mendoza GA, Aguirre-Olivas D, Méndez B, Moore S, Sánchez-Sugía C, García-Aguilera MA, Martínez-Valencia A, Ramírez-Santiago G, Rubí JM. Extrasynaptic Communication. Front Mol Neurosci 2021; 14:638858. [PMID: 33994942 PMCID: PMC8119753 DOI: 10.3389/fnmol.2021.638858] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Accepted: 04/01/2021] [Indexed: 12/18/2022] Open
Abstract
Streams of action potentials or long depolarizations evoke a massive exocytosis of transmitters and peptides from the surface of dendrites, axons and cell bodies of different neuron types. Such mode of exocytosis is known as extrasynaptic for occurring without utilization of synaptic structures. Most transmitters and all peptides can be released extrasynaptically. Neurons may discharge their contents with relative independence from the axon, soma and dendrites. Extrasynaptic exocytosis takes fractions of a second in varicosities or minutes in the soma or dendrites, but its effects last from seconds to hours. Unlike synaptic exocytosis, which is well localized, extrasynaptic exocytosis is diffuse and affects neuronal circuits, glia and blood vessels. Molecules that are liberated may reach extrasynaptic receptors microns away. The coupling between excitation and exocytosis follows a multistep mechanism, different from that at synapses, but similar to that for the release of hormones. The steps from excitation to exocytosis have been studied step by step for the vital transmitter serotonin in leech Retzius neurons. The events leading to serotonin exocytosis occur similarly for the release of other transmitters and peptides in central and peripheral neurons. Extrasynaptic exocytosis occurs commonly onto glial cells, which react by releasing the same or other transmitters. In the last section, we discuss how illumination of the retina evokes extrasynaptic release of dopamine and ATP. Dopamine contributes to light-adaptation; ATP activates glia, which mediates an increase in blood flow and oxygenation. A proper understanding of the workings of the nervous system requires the understanding of extrasynaptic communication.
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Affiliation(s)
- Francisco F De-Miguel
- Instituto de Fisiología Celular-Neurociencias, Universidad Nacional Autónoma de México, México City, Mexico.,Centro de Ciencias de la Complejidad, Universidad Nacional Autónoma de México, México City, Mexico
| | - Carolina Leon-Pinzon
- Instituto de Fisiología Celular-Neurociencias, Universidad Nacional Autónoma de México, México City, Mexico
| | - Susana G Torres-Platas
- Instituto de Fisiología Celular-Neurociencias, Universidad Nacional Autónoma de México, México City, Mexico
| | - Vanessa Del-Pozo
- Instituto de Fisiología Celular-Neurociencias, Universidad Nacional Autónoma de México, México City, Mexico
| | | | - Dilia Aguirre-Olivas
- Instituto de Fisiología Celular-Neurociencias, Universidad Nacional Autónoma de México, México City, Mexico
| | - Bruno Méndez
- Instituto de Fisiología Celular-Neurociencias, Universidad Nacional Autónoma de México, México City, Mexico
| | - Sharlen Moore
- Instituto de Fisiología Celular-Neurociencias, Universidad Nacional Autónoma de México, México City, Mexico
| | - Celeste Sánchez-Sugía
- Instituto de Fisiología Celular-Neurociencias, Universidad Nacional Autónoma de México, México City, Mexico
| | | | | | | | - J Miguel Rubí
- Facultat de Fisica, Universitat de Barcelona, Barcelona, Spain
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194
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Uddin MS, Hasana S, Ahmad J, Hossain MF, Rahman MM, Behl T, Rauf A, Ahmad A, Hafeez A, Perveen A, Ashraf GM. Anti-Neuroinflammatory Potential of Polyphenols by Inhibiting NF-κB to Halt Alzheimer's Disease. Curr Pharm Des 2021; 27:402-414. [PMID: 33213314 DOI: 10.2174/1381612826666201118092422] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Accepted: 10/01/2020] [Indexed: 11/22/2022]
Abstract
Alzheimer's disease (AD) is an irrevocable chronic brain disorder featured by neuronal loss, microglial accumulation, and progressive cognitive impairment. The proper pathophysiology of this life-threatening disorder is not completely understood and no exact remedies have been found yet. Over the last few decades, research on AD has mainly highlighted pathomechanisms linked to a couple of the major pathological hallmarks, including extracellular senile plaques made of amyloid-β (Aβ) peptides, and intracellular neurofibrillary tangles (NFTs) made of tau proteins. Aβ can induce apoptosis, trigger an inflammatory response, and inhibit the synaptic plasticity of the hippocampus, which ultimately contributes to reducing cognitive functions and memory impairment. Recently, a third disease hallmark, the neuroinflammatory reaction that is mediated by cerebral innate immune cells, has become a spotlight in the current research area, assured by pre-clinical, clinical, and genetic investigations. Nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), a cytokine producer, is significantly associated with physiological inflammatory proceedings and thus shows a promising candidate for inflammation- based AD therapy. Recent data reveal that phytochemicals, mainly polyphenol compounds, exhibit potential neuroprotective functions and these may be considered as a vital resource for discovering several drug candidates against AD. Interestingly, phytochemicals can easily interfere with the signaling pathway of NF-κB. This review represents the anti-neuroinflammatory potential of polyphenols as inhibitors of NF-κB to combat AD pathogenesis.
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Affiliation(s)
- Md Sahab Uddin
- Department of Pharmacy, Southeast University, Dhaka, Bangladesh
| | - Sharifa Hasana
- Department of Pharmacy, Southeast University, Dhaka, Bangladesh
| | - Jamil Ahmad
- Department of Human Nutrition, The University of Agriculture Peshawar, Khyber Pakhtunkhwa, Pakistan
| | | | | | - Tapan Behl
- Chitkara College of Pharmacy, Chitkara University, Punjab, India
| | - Abdur Rauf
- Department of Chemistry, University of Swabi, Swabi, Anbar, Khyber Pakhtunkhwa, Pakistan
| | - Ausaf Ahmad
- Amity Institute of Biotechnology, Amity University Uttar Pradesh Lucknow Campus, Uttar Pradesh, India
| | - Abdul Hafeez
- Glocal School of Pharmacy, Glocal University, Saharanpur, India
| | - Asma Perveen
- Glocal School of Life Sciences, Glocal University, Saharanpur, India
| | - Ghulam Md Ashraf
- King Fahd Medical Research Center, King Abdulaziz University, Jeddah, Saudi Arabia
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195
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Szabó Z, Péter M, Héja L, Kardos J. Dual Role for Astroglial Copper-Assisted Polyamine Metabolism during Intense Network Activity. Biomolecules 2021; 11:604. [PMID: 33921742 PMCID: PMC8073386 DOI: 10.3390/biom11040604] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Revised: 04/09/2021] [Accepted: 04/14/2021] [Indexed: 12/29/2022] Open
Abstract
Astrocytes serve essential roles in human brain function and diseases. Growing evidence indicates that astrocytes are central players of the feedback modulation of excitatory Glu signalling during epileptiform activity via Glu-GABA exchange. The underlying mechanism results in the increase of tonic inhibition by reverse operation of the astroglial GABA transporter, induced by Glu-Na+ symport. GABA, released from astrocytes, is synthesized from the polyamine (PA) putrescine and this process involves copper amino oxidase. Through this pathway, putrescine can be considered as an important source of inhibitory signaling that counterbalances epileptic discharges. Putrescine, however, is also a precursor for spermine that is known to enhance gap junction channel communication and, consequently, supports long-range Ca2+ signaling and contributes to spreading of excitatory activity through the astrocytic syncytium. Recently, we presented the possibility of neuron-glia redox coupling through copper (Cu+/Cu2+) signaling and oxidative putrescine catabolism. In the current work, we explore whether the Cu+/Cu2+ homeostasis is involved in astrocytic control on neuronal excitability by regulating PA catabolism. We provide supporting experimental data underlying this hypothesis. We show that the blockade of copper transporter (CTR1) by AgNO3 (3.6 µM) prevents GABA transporter-mediated tonic inhibitory currents, indicating causal relationship between copper (Cu+/Cu2+) uptake and the catabolism of putrescine to GABA in astrocytes. In addition, we show that MnCl2 (20 μM), an inhibitor of the divalent metal transporter DMT1, also prevents the astrocytic Glu-GABA exchange. Furthermore, we observed that facilitation of copper uptake by added CuCl2 (2 µM) boosts tonic inhibitory currents. These findings corroborate the hypothesis that modulation of neuron-glia coupling by copper uptake drives putrescine → GABA transformation, which leads to subsequent Glu-GABA exchange and tonic inhibition. Findings may in turn highlight the potential role of copper signaling in fine-tuning the activity of the tripartite synapse.
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Affiliation(s)
- Zsolt Szabó
- Functional Pharmacology Research Group, Research Centre for Natural Sciences, Institute of Organic Chemistry, H-1117 Budapest, Hungary; (Z.S.); (M.P.); (J.K.)
| | - Márton Péter
- Functional Pharmacology Research Group, Research Centre for Natural Sciences, Institute of Organic Chemistry, H-1117 Budapest, Hungary; (Z.S.); (M.P.); (J.K.)
- Hevesy György Ph.D. School of Chemistry, ELTE Eötvös Loránd University, H-1117 Budapest, Hungary
| | - László Héja
- Functional Pharmacology Research Group, Research Centre for Natural Sciences, Institute of Organic Chemistry, H-1117 Budapest, Hungary; (Z.S.); (M.P.); (J.K.)
| | - Julianna Kardos
- Functional Pharmacology Research Group, Research Centre for Natural Sciences, Institute of Organic Chemistry, H-1117 Budapest, Hungary; (Z.S.); (M.P.); (J.K.)
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196
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Wang Y, Fu AKY, Ip NY. Instructive roles of astrocytes in hippocampal synaptic plasticity: neuronal activity-dependent regulatory mechanisms. FEBS J 2021; 289:2202-2218. [PMID: 33864430 PMCID: PMC9290076 DOI: 10.1111/febs.15878] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Revised: 03/02/2021] [Accepted: 04/12/2021] [Indexed: 12/22/2022]
Abstract
In the adult hippocampus, synaptic plasticity is important for information processing, learning, and memory encoding. Astrocytes, the most common glial cells, play a pivotal role in the regulation of hippocampal synaptic plasticity. While astrocytes were initially described as a homogenous cell population, emerging evidence indicates that in the adult hippocampus, astrocytes are highly heterogeneous and can differentially respond to changes in neuronal activity in a subregion‐dependent manner to actively modulate synaptic plasticity. In this review, we summarize how local neuronal activity changes regulate the interactions between astrocytes and synapses, either by modulating the secretion of gliotransmitters and synaptogenic proteins or via contact‐mediated signaling pathways. In turn, these specific responses induced in astrocytes mediate the interactions between astrocytes and neurons, thus shaping synaptic communication in the adult hippocampus. Importantly, the activation of astrocytic signaling is required for memory performance including memory acquisition and recall. Meanwhile, the dysregulation of this signaling can cause hippocampal circuit dysfunction in pathological conditions, resulting in cognitive impairment and neurodegeneration. Indeed, reactive astrocytes, which have dysregulated signaling associated with memory, are induced in the brains of patients with Alzheimer's disease (AD) and transgenic mouse model of AD. Emerging technologies that can precisely manipulate and monitor astrocytic signaling in vivo enable the examination of the specific actions of astrocytes in response to neuronal activity changes as well as how they modulate synaptic connections and circuit activity. Such findings will clarify the roles of astrocytes in hippocampal synaptic plasticity and memory in health and disease.
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Affiliation(s)
- Ye Wang
- Division of Life Science, The Hong Kong University of Science and Technology, China.,Molecular Neuroscience Center, The Hong Kong University of Science and Technology, China.,State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, China.,Hong Kong Center for Neurodegenerative Diseases, China
| | - Amy K Y Fu
- Division of Life Science, The Hong Kong University of Science and Technology, China.,Molecular Neuroscience Center, The Hong Kong University of Science and Technology, China.,State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, China.,Hong Kong Center for Neurodegenerative Diseases, China.,Guangdong Provincial Key Laboratory of Brain Science, Disease and Drug Development, HKUST Shenzhen Research Institute, Shenzhen-Hong Kong Institute of Brain Science, Shenzhen, China
| | - Nancy Y Ip
- Division of Life Science, The Hong Kong University of Science and Technology, China.,Molecular Neuroscience Center, The Hong Kong University of Science and Technology, China.,State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, China.,Hong Kong Center for Neurodegenerative Diseases, China.,Guangdong Provincial Key Laboratory of Brain Science, Disease and Drug Development, HKUST Shenzhen Research Institute, Shenzhen-Hong Kong Institute of Brain Science, Shenzhen, China
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197
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Wu Q, Huang J, Wu R. Drugs Based on NMDAR Hypofunction Hypothesis in Schizophrenia. Front Neurosci 2021; 15:641047. [PMID: 33912003 PMCID: PMC8072017 DOI: 10.3389/fnins.2021.641047] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2020] [Accepted: 03/12/2021] [Indexed: 12/30/2022] Open
Abstract
Treatments for negative symptoms and cognitive dysfunction in schizophrenia remain issues that psychiatrists around the world are trying to solve. Their mechanisms may be associated with N-methyl-D-aspartate receptors (NMDARs). The NMDAR hypofunction hypothesis for schizophrenia was brought to the fore mainly based on the clinical effects of NMDAR antagonists and anti-NMDAR encephalitis pathology. Drugs targeted at augmenting NMDAR function in the brain seem to be promising in improving negative symptoms and cognitive dysfunction in patients with schizophrenia. In this review, we list NMDAR-targeted drugs and report on related clinical studies. We then summarize their effects on negative symptoms and cognitive dysfunction and analyze the unsatisfactory outcomes of these clinical studies according to the improved glutamate hypothesis that has been revealed in animal models. We aimed to provide perspectives for scientists who sought therapeutic strategies for negative symptoms and cognitive dysfunction in schizophrenia based on the NMDAR hypofunction hypothesis.
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Affiliation(s)
- Qiongqiong Wu
- Department of Psychiatry, National Clinical Research Center for Mental Disorders, The Second Xiangya Hospital of Central South University, Changsha, China
| | - Jing Huang
- Department of Psychiatry, National Clinical Research Center for Mental Disorders, The Second Xiangya Hospital of Central South University, Changsha, China
| | - Renrong Wu
- Department of Psychiatry, National Clinical Research Center for Mental Disorders, The Second Xiangya Hospital of Central South University, Changsha, China
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198
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Sensing and Regulating Synaptic Activity by Astrocytes at Tripartite Synapse. Neurochem Res 2021; 46:2580-2585. [PMID: 33837868 PMCID: PMC10159683 DOI: 10.1007/s11064-021-03317-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Revised: 03/27/2021] [Accepted: 03/29/2021] [Indexed: 12/11/2022]
Abstract
Astrocytes are recognized as more important cells than historically thought in synaptic function through the reciprocal exchange of signaling with the neuronal synaptic elements. The idea that astrocytes are active elements in synaptic physiology is conceptualized in the Tripartite Synapse concept. This review article presents and discusses recent representative examples that highlight the heterogeneity of signaling in tripartite synapse function and its consequences on neural network function and animal behavior.
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199
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Austin T, Bani-Ahmed A, Cirstea MC. N-Acetylaspartate Biomarker of Stroke Recovery: A Case Series Study. FRONTIERS IN NEUROLOGY AND NEUROSCIENCE RESEARCH 2021; 2:100007. [PMID: 34296219 PMCID: PMC8294783] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
BACKGROUND AND PURPOSE Strong experimental neurobehavioral evidence suggests that intensive training improves arm motor disability after stroke. Yet, we still have only limited understanding why some patients recover more completely and others do not. This is in part due to our limited knowledge of the neurobiological principles of recovery from stroke. Mounting evidence suggests that functional and structural remapping of the primary motor cortex (M1) plays a major role in arm recovery after stroke. We used MR Spectroscopy to test the hypothesis that therapy-related arm improvement is associated with changes in levels of a putative marker of neuronal integrity (N-acetylaspartate, NAA) in M1 controlling the paretic arm (ipsilesional M1) in chronic stroke patients (n=5). METHODS Patients (1 female, age, mean ± SD, 58.4 ± 5.8 years) underwent 4-week arm-focused motor training (1080 repetitions of a reach-to-grasp task) at 13.6 ± 5.3 months after stroke onset. NAA levels in the ipsilesional M1 and arm impairment (Fugl-Meyer, FM, 66=normal; proximal FM, FMp, 30=normal) were assessed prior to and immediately after training. RESULTS At baseline, patients exhibited moderate-to-mild arm impairment (FM, 47.2 ± 18.8, FMp, 22.2 ± 8.6) and showed lower levels of NAA compared with age/sex-matched healthy controls (10.2 ± 0.9 mM in patients vs. 11.6 ± 1.6 mM in controls, p=0.03). After training, arm impairment improved (FM by 7%, 50.6 ± 17.5, p=0.01; FMp, by 5%, 23.4 ± 8.2, p=0.2) and NAA levels increased by 10.5% (11.2 ± 1.2 mM, p=0.1). Changes in NAA positively correlated with changes in FM (r=0.63, p=0.2) and FMp (r=0.93, p=0.03), suggesting that patients who show greater neuronal changes have a better chance of recovery. CONCLUSIONS Our data suggest the potential use of M1 NAA as a biomarker of motor recovery after stroke. However, because of our small sample, these preliminary results should be interpreted cautiously. Further work with larger sample sizes is warranted.
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Affiliation(s)
- Tyler Austin
- University of Missouri School of Medicine, Columbia, Missouri, USA
| | - Ali Bani-Ahmed
- Hoglund Brain Imaging Center, University of Kansas Medical Center, Kansas City, Kansas, USA
- Department of Physical Therapy & Rehabilitation Science, University of Kansas Medical Center, Kansas City, Kansas, USA
- Department of Rehabilitation Sciences, Jordan University of Science and Technology, Ar-Ramtha, Jordan
| | - Mihaela Carmen Cirstea
- Hoglund Brain Imaging Center, University of Kansas Medical Center, Kansas City, Kansas, USA
- Department of Physical Therapy & Rehabilitation Science, University of Kansas Medical Center, Kansas City, Kansas, USA
- Department of Neurology, University of Kansas Medical Center, Kansas City, Kansas, USA
- Department of Physical Medicine & Rehabilitation, University of Missouri, Columbia, Missouri, USA
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200
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Gordleeva SY, Tsybina YA, Krivonosov MI, Ivanchenko MV, Zaikin AA, Kazantsev VB, Gorban AN. Modeling Working Memory in a Spiking Neuron Network Accompanied by Astrocytes. Front Cell Neurosci 2021; 15:631485. [PMID: 33867939 PMCID: PMC8044545 DOI: 10.3389/fncel.2021.631485] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Accepted: 03/04/2021] [Indexed: 01/07/2023] Open
Abstract
We propose a novel biologically plausible computational model of working memory (WM) implemented by a spiking neuron network (SNN) interacting with a network of astrocytes. The SNN is modeled by synaptically coupled Izhikevich neurons with a non-specific architecture connection topology. Astrocytes generating calcium signals are connected by local gap junction diffusive couplings and interact with neurons via chemicals diffused in the extracellular space. Calcium elevations occur in response to the increased concentration of the neurotransmitter released by spiking neurons when a group of them fire coherently. In turn, gliotransmitters are released by activated astrocytes modulating the strength of the synaptic connections in the corresponding neuronal group. Input information is encoded as two-dimensional patterns of short applied current pulses stimulating neurons. The output is taken from frequencies of transient discharges of corresponding neurons. We show how a set of information patterns with quite significant overlapping areas can be uploaded into the neuron-astrocyte network and stored for several seconds. Information retrieval is organized by the application of a cue pattern representing one from the memory set distorted by noise. We found that successful retrieval with the level of the correlation between the recalled pattern and ideal pattern exceeding 90% is possible for the multi-item WM task. Having analyzed the dynamical mechanism of WM formation, we discovered that astrocytes operating at a time scale of a dozen of seconds can successfully store traces of neuronal activations corresponding to information patterns. In the retrieval stage, the astrocytic network selectively modulates synaptic connections in the SNN leading to successful recall. Information and dynamical characteristics of the proposed WM model agrees with classical concepts and other WM models.
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Affiliation(s)
- Susanna Yu Gordleeva
- Scientific and Educational Mathematical Center "Mathematics of Future Technology," Lobachevsky State University of Nizhny Novgorod, Nizhny Novgorod, Russia.,Neuroscience and Cognitive Technology Laboratory, Center for Technologies in Robotics and Mechatronics Components, Innopolis University, Innopolis, Russia
| | - Yuliya A Tsybina
- Scientific and Educational Mathematical Center "Mathematics of Future Technology," Lobachevsky State University of Nizhny Novgorod, Nizhny Novgorod, Russia
| | - Mikhail I Krivonosov
- Scientific and Educational Mathematical Center "Mathematics of Future Technology," Lobachevsky State University of Nizhny Novgorod, Nizhny Novgorod, Russia
| | - Mikhail V Ivanchenko
- Scientific and Educational Mathematical Center "Mathematics of Future Technology," Lobachevsky State University of Nizhny Novgorod, Nizhny Novgorod, Russia
| | - Alexey A Zaikin
- Scientific and Educational Mathematical Center "Mathematics of Future Technology," Lobachevsky State University of Nizhny Novgorod, Nizhny Novgorod, Russia.,Center for Analysis of Complex Systems, Sechenov First Moscow State Medical University, Sechenov University, Moscow, Russia.,Institute for Women's Health and Department of Mathematics, University College London, London, United Kingdom
| | - Victor B Kazantsev
- Scientific and Educational Mathematical Center "Mathematics of Future Technology," Lobachevsky State University of Nizhny Novgorod, Nizhny Novgorod, Russia.,Neuroscience and Cognitive Technology Laboratory, Center for Technologies in Robotics and Mechatronics Components, Innopolis University, Innopolis, Russia.,Neuroscience Research Institute, Samara State Medical University, Samara, Russia
| | - Alexander N Gorban
- Scientific and Educational Mathematical Center "Mathematics of Future Technology," Lobachevsky State University of Nizhny Novgorod, Nizhny Novgorod, Russia.,Department of Mathematics, University of Leicester, Leicester, United Kingdom
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