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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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52
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Dos Santos RR, Bernardino TC, da Silva MCM, de Oliveira ACP, Drumond LE, Rosa DV, Massensini AR, Moraes MFD, Doretto MC, Romano-Silva MA, Reis HJ. Neurochemical abnormalities in the hippocampus of male rats displaying audiogenic seizures, a genetic model of epilepsy. Neurosci Lett 2021; 761:136123. [PMID: 34293418 DOI: 10.1016/j.neulet.2021.136123] [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: 02/27/2021] [Revised: 07/11/2021] [Accepted: 07/16/2021] [Indexed: 11/17/2022]
Abstract
BACKGROUND Epilepsy is a disorder characterized by recurrent seizures that affects 1% of the population. However, the neurochemical alterations observed in epilepsy are not fully understood. There are different animal models of epilepsy, such as genetic or drug induced. In the present study, we utilize Wistar Audiogenic Rats (WAR), a murine strain that develops seizures in response to high intensity audio stimulation, in order to investigate abnormalities in glutamatergic and GABAergic systems. METHODS Synaptosomes and glial plasmalemmal vesicles were prepared from hippocampus and cortex, respectively. Glutamate and GABA release and uptake were assayed by monitoring the fluorescence and using L-[3H]-radiolabeled compounds. Glutamate and calcium concentration in the synaptosomes were also measured. The expression of neuronal calcium sensor 1 (NCS-1) was determined by western blot. RESULTS Glutamate and GABA release evoked by KCl was decreased in WAR compared to control Wistar rats. Calcium independent release was not considerably different in both groups. The total amount of glutamate of synaptosomes, as well as glutamate uptake by synaptosomes and GPV were also decreased in WAR in comparison with the controls. In addition, [Ca2+]i of hippocampal synaptosomes, as well as NCS-1 expression in the hippocampus, were increased in WAR in comparison with controls. CONCLUSION In conclusion, our results suggest that WAR have important alterations in the glutamatergic and GABAergic pathways, as well as an increased expression of NCS-1 in the hippocampus and inferior colliculus. These alterations may be linked to the spreading of hyperexcitability and recruitment of various brain regions.
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Affiliation(s)
- Rodrigo Ribeiro Dos Santos
- Departamento de Saúde Mental, Faculdade de Medicina, Universidade Federal de Minas Gerais. Av Alfredo Balena 190, CEP 30130-100 Belo Horizonte, MG, Brazil; Laboratório de Neurofarmacologia, Departamento de Farmacologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais. Av Antonio Carlos 6627, Campus Pampulha, CEP 30190-901 Belo Horizonte, MG, Brazil
| | - Túlio C Bernardino
- Laboratório de Neurofarmacologia, Departamento de Farmacologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais. Av Antonio Carlos 6627, Campus Pampulha, CEP 30190-901 Belo Horizonte, MG, Brazil
| | - Maria Carolina Machado da Silva
- Laboratório de Neurofarmacologia, Departamento de Farmacologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais. Av Antonio Carlos 6627, Campus Pampulha, CEP 30190-901 Belo Horizonte, MG, Brazil
| | - Antônio C P de Oliveira
- Laboratório de Neurofarmacologia, Departamento de Farmacologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais. Av Antonio Carlos 6627, Campus Pampulha, CEP 30190-901 Belo Horizonte, MG, Brazil
| | - Luciana E Drumond
- Núcleo de Neurociências, Departamento de Biofísica e Fisiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais. Av Antonio Carlos 6627, Campus Pampulha, CEP 30190-901 Belo Horizonte, MG, Brazil
| | - Daniela V Rosa
- Departamento de Saúde Mental, Faculdade de Medicina, Universidade Federal de Minas Gerais. Av Alfredo Balena 190, CEP 30130-100 Belo Horizonte, MG, Brazil
| | - André R Massensini
- Núcleo de Neurociências, Departamento de Biofísica e Fisiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais. Av Antonio Carlos 6627, Campus Pampulha, CEP 30190-901 Belo Horizonte, MG, Brazil
| | - Márcio F D Moraes
- Núcleo de Neurociências, Departamento de Biofísica e Fisiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais. Av Antonio Carlos 6627, Campus Pampulha, CEP 30190-901 Belo Horizonte, MG, Brazil
| | - Maria C Doretto
- Núcleo de Neurociências, Departamento de Biofísica e Fisiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais. Av Antonio Carlos 6627, Campus Pampulha, CEP 30190-901 Belo Horizonte, MG, Brazil
| | - Marco A Romano-Silva
- Departamento de Saúde Mental, Faculdade de Medicina, Universidade Federal de Minas Gerais. Av Alfredo Balena 190, CEP 30130-100 Belo Horizonte, MG, Brazil
| | - Helton J Reis
- Laboratório de Neurofarmacologia, Departamento de Farmacologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais. Av Antonio Carlos 6627, Campus Pampulha, CEP 30190-901 Belo Horizonte, MG, Brazil.
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53
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Heuser K, Enger R. Astrocytic Ca 2+ Signaling in Epilepsy. Front Cell Neurosci 2021; 15:695380. [PMID: 34335188 PMCID: PMC8320018 DOI: 10.3389/fncel.2021.695380] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Accepted: 06/16/2021] [Indexed: 01/10/2023] Open
Abstract
Epilepsy is one of the most common neurological disorders – estimated to affect at least 65 million worldwide. Most of the epilepsy research has so far focused on how to dampen neuronal discharges and to explain how changes in intrinsic neuronal activity or network function cause seizures. As a result, pharmacological therapy has largely been limited to symptomatic treatment targeted at neurons. Given the expanding spectrum of functions ascribed to the non-neuronal constituents of the brain, in both physiological brain function and in brain disorders, it is natural to closely consider the roles of astrocytes in epilepsy. It is now widely accepted that astrocytes are key controllers of the composition of the extracellular fluids, and may directly interact with neurons by releasing gliotransmitters. A central tenet is that astrocytic intracellular Ca2+ signals promote release of such signaling substances, either through synaptic or non-synaptic mechanisms. Accruing evidence suggests that astrocytic Ca2+ signals play important roles in both seizures and epilepsy, and this review aims to highlight the current knowledge of the roles of this central astrocytic signaling mechanism in ictogenesis and epileptogenesis.
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Affiliation(s)
- Kjell Heuser
- Department of Neurology, Oslo University Hospital, Rikshospitalet, Oslo, Norway
| | - Rune Enger
- Letten Centre and GliaLab, Division of Anatomy, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
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54
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Shan L, Zhang T, Fan K, Cai W, Liu H. Astrocyte-Neuron Signaling in Synaptogenesis. Front Cell Dev Biol 2021; 9:680301. [PMID: 34277621 PMCID: PMC8284252 DOI: 10.3389/fcell.2021.680301] [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: 03/14/2021] [Accepted: 06/14/2021] [Indexed: 01/10/2023] Open
Abstract
Astrocytes are the key component of the central nervous system (CNS), serving as pivotal regulators of neuronal synapse formation and maturation through their ability to dynamically and bidirectionally communicate with synapses throughout life. In the past 20 years, numerous astrocyte-derived molecules promoting synaptogenesis have been discovered. However, our understanding of the cell biological basis underlying intra-neuron processes and astrocyte-mediated synaptogenesis is still in its infancy. Here, we provide a comprehensive overview of the various ways astrocytes talk to neurons, and highlight astrocytes’ heterogeneity that allow them to displays regional-specific capabilities in boosting synaptogenesis. Finally, we conclude with promises and future directions on how organoids generated from human induced pluripotent stem cells (hiPSCs) effectively address the signaling pathways astrocytes employ in synaptic development.
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Affiliation(s)
- Lili Shan
- Guangzhou Laboratory, Guangzhou, China.,Bioland Laboratory (Guangzhou Regenerative Medicine and Health Guangdong Laboratory), Guangzhou, China
| | - Tongran Zhang
- Guangzhou Laboratory, Guangzhou, China.,Bioland Laboratory (Guangzhou Regenerative Medicine and Health Guangdong Laboratory), Guangzhou, China
| | - Kevin Fan
- Department of Radiology, University of Wisconsin-Madison, Madison, WI, United States.,Department of Medical Physics, University of Wisconsin-Madison, Madison, WI, United States
| | - Weibo Cai
- Department of Radiology, University of Wisconsin-Madison, Madison, WI, United States.,Department of Medical Physics, University of Wisconsin-Madison, Madison, WI, United States
| | - Huisheng Liu
- Guangzhou Laboratory, Guangzhou, China.,Bioland Laboratory (Guangzhou Regenerative Medicine and Health Guangdong Laboratory), Guangzhou, China
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55
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Javdani M, Ghorbani R, Hashemnia M. Histopathological Evaluation of Spinal Cord with Experimental Traumatic Injury Following Implantation of a Controlled Released Drug Delivery System of Chitosan Hydrogel Loaded with Selenium Nanoparticle. Biol Trace Elem Res 2021; 199:2677-2686. [PMID: 32959339 DOI: 10.1007/s12011-020-02395-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/18/2020] [Accepted: 09/13/2020] [Indexed: 10/23/2022]
Abstract
The purpose of this study was to evaluate the neuroprotective effect of local implantation of a controlled delivery system of chitosan hydrogel loaded with selenium nanoparticles in rats with spinal cord injury (SCI). For this purpose, 60 adult female rats were randomly divided into three equal groups. In all three groups, SCI was induced by aneurysm clamping at the level of thoracic vertebrae under inhaled anesthesia with isoflurane. In one group after spinal cord injury, chitosan hydrogels loaded with selenium nanoparticles (treatment group), and in the other group, only chitosan hydrogels (positive control group) were placed at the site of injury. In the last group (negative control), no material was placed in the injury site. Hematoxylin-eosin and glial fibrillary acidic protein (GFAP) staining evaluated histological changes at the site of injury on days 3, 7, 21, and 28 after surgery. Evaluations show that hemorrhage and inflammation also have a marked decrease in inflammatory cells at different times in the treatment group. This decrease was also seen in the chitosan group but was less severe than in the treatment group. The formation of nerve fibers was also observed in the treatment group over time of injury. Immunohistochemical studies of damaged tissue showed higher expression of GFAP protein in the astrocytes of the treatment group than in the other two groups and the chitosan group compared with the negative control group. A controlled drug delivery system containing selenium nanoparticles seems to play a role in the protection of nerve cells through its anti-inflammatory effect.
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Affiliation(s)
- Moosa Javdani
- Department of Clinical Sciences, Faculty of Veterinary Medicine, Shahrekord University, 115, Shahrekord, Iran.
| | - Roya Ghorbani
- Department of Clinical Sciences, Faculty of Veterinary Medicine, Shahrekord University, 115, Shahrekord, Iran
| | - Mohammad Hashemnia
- Department of Pathobiology, Faculty of Veterinary Medicine, Razi University, Kermanshah, Iran
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56
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Wang Q, Kong Y, Lin S, Wu DY, Hu J, Huang L, Zang WS, Li XW, Yang JM, Gao TM. The ATP Level in the mPFC Mediates the Antidepressant Effect of Calorie Restriction. Neurosci Bull 2021; 37:1303-1313. [PMID: 34089507 DOI: 10.1007/s12264-021-00726-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Accepted: 01/31/2021] [Indexed: 11/25/2022] Open
Abstract
Food deprivation can rescue obesity and overweight-induced mood disorders, and promote mood performance in normal subjects. Animal studies and clinical research have revealed the antidepressant-like effect of calorie restriction, but little is known about the mechanism of calorie restriction-induced mood modification. Previous studies have found that astrocytes modulate depressive-like behaviors. Inositol 1,4,5-trisphosphate receptor type 2 (IP3R2) is the predominant isoform in mediating astrocyte Ca2+ signals and its genetic knockout mice are widely used to study astrocyte function in vivo. In this study, we showed that deletion of IP3R2 blocked the antidepressant-like effect induced by calorie restriction. In vivo microdialysis experiments demonstrated that calorie restriction induced an increase in ATP level in the medial prefrontal cortex (mPFC) in naïve mice but this effect disappeared in IP3R2-knockout mice, suggesting a role of astrocytic ATP in the calorie restriction-induced antidepressant effect. Further experiments showed that systemic administration and local infusion of ATP into the mPFC induced an antidepressant effect, whereas decreasing ATP by Apyrase in the mPFC blocked calorie restriction-induced antidepressant regulation. Together, these findings support a role for astrocytic ATP in the antidepressant-like effect caused by calorie restriction.
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Affiliation(s)
- Qian Wang
- State Key Laboratory of Organ Failure Research, Key Laboratory of Mental Health of the Ministry of Education, Guangdong-Hong Kong-Macao Greater Bay Area Center for Brian Science and Brain-Inspired Intelligence, Guangdong Province Key Laboratory of Psychiatric Disorders, Department of Neurobiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, 510515, China
| | - Ying Kong
- State Key Laboratory of Organ Failure Research, Key Laboratory of Mental Health of the Ministry of Education, Guangdong-Hong Kong-Macao Greater Bay Area Center for Brian Science and Brain-Inspired Intelligence, Guangdong Province Key Laboratory of Psychiatric Disorders, Department of Neurobiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, 510515, China
| | - Song Lin
- State Key Laboratory of Organ Failure Research, Key Laboratory of Mental Health of the Ministry of Education, Guangdong-Hong Kong-Macao Greater Bay Area Center for Brian Science and Brain-Inspired Intelligence, Guangdong Province Key Laboratory of Psychiatric Disorders, Department of Neurobiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, 510515, China
| | - Ding-Yu Wu
- State Key Laboratory of Organ Failure Research, Key Laboratory of Mental Health of the Ministry of Education, Guangdong-Hong Kong-Macao Greater Bay Area Center for Brian Science and Brain-Inspired Intelligence, Guangdong Province Key Laboratory of Psychiatric Disorders, Department of Neurobiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, 510515, China
| | - Jian Hu
- State Key Laboratory of Organ Failure Research, Key Laboratory of Mental Health of the Ministry of Education, Guangdong-Hong Kong-Macao Greater Bay Area Center for Brian Science and Brain-Inspired Intelligence, Guangdong Province Key Laboratory of Psychiatric Disorders, Department of Neurobiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, 510515, China
| | - Lang Huang
- State Key Laboratory of Organ Failure Research, Key Laboratory of Mental Health of the Ministry of Education, Guangdong-Hong Kong-Macao Greater Bay Area Center for Brian Science and Brain-Inspired Intelligence, Guangdong Province Key Laboratory of Psychiatric Disorders, Department of Neurobiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, 510515, China
| | - Wen-Si Zang
- State Key Laboratory of Organ Failure Research, Key Laboratory of Mental Health of the Ministry of Education, Guangdong-Hong Kong-Macao Greater Bay Area Center for Brian Science and Brain-Inspired Intelligence, Guangdong Province Key Laboratory of Psychiatric Disorders, Department of Neurobiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, 510515, China
| | - Xiao-Wen Li
- State Key Laboratory of Organ Failure Research, Key Laboratory of Mental Health of the Ministry of Education, Guangdong-Hong Kong-Macao Greater Bay Area Center for Brian Science and Brain-Inspired Intelligence, Guangdong Province Key Laboratory of Psychiatric Disorders, Department of Neurobiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, 510515, China
| | - Jian-Ming Yang
- State Key Laboratory of Organ Failure Research, Key Laboratory of Mental Health of the Ministry of Education, Guangdong-Hong Kong-Macao Greater Bay Area Center for Brian Science and Brain-Inspired Intelligence, Guangdong Province Key Laboratory of Psychiatric Disorders, Department of Neurobiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, 510515, China
| | - Tian-Ming Gao
- State Key Laboratory of Organ Failure Research, Key Laboratory of Mental Health of the Ministry of Education, Guangdong-Hong Kong-Macao Greater Bay Area Center for Brian Science and Brain-Inspired Intelligence, Guangdong Province Key Laboratory of Psychiatric Disorders, Department of Neurobiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, 510515, China.
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57
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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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58
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van Putten MJ, Fahlke C, Kafitz KW, Hofmeijer J, Rose CR. Dysregulation of Astrocyte Ion Homeostasis and Its Relevance for Stroke-Induced Brain Damage. Int J Mol Sci 2021; 22:5679. [PMID: 34073593 PMCID: PMC8198632 DOI: 10.3390/ijms22115679] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Revised: 05/21/2021] [Accepted: 05/22/2021] [Indexed: 12/14/2022] Open
Abstract
Ischemic stroke is a leading cause of mortality and chronic disability. Either recovery or progression towards irreversible failure of neurons and astrocytes occurs within minutes to days, depending on remaining perfusion levels. Initial damage arises from energy depletion resulting in a failure to maintain homeostasis and ion gradients between extra- and intracellular spaces. Astrocytes play a key role in these processes and are thus central players in the dynamics towards recovery or progression of stroke-induced brain damage. Here, we present a synopsis of the pivotal functions of astrocytes at the tripartite synapse, which form the basis of physiological brain functioning. We summarize the evidence of astrocytic failure and its consequences under ischemic conditions. Special emphasis is put on the homeostasis and stroke-induced dysregulation of the major monovalent ions, namely Na+, K+, H+, and Cl-, and their involvement in maintenance of cellular volume and generation of cerebral edema.
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Affiliation(s)
- Michel J.A.M. van Putten
- Department of Clinical Neurophysiology, University of Twente, 7522 NB Enschede, The Netherlands; (M.J.A.M.v.P.); (J.H.)
| | - Christoph Fahlke
- Institut für Biologische Informationsprozesse, Molekular-und Zellphysiologie (IBI-1), Forschungszentrum Jülich, 52425 Jülich, Germany;
| | - Karl W. Kafitz
- Institute of Neurobiology, Heinrich Heine University Düsseldorf, 40225 Düsseldorf, Germany;
| | - Jeannette Hofmeijer
- Department of Clinical Neurophysiology, University of Twente, 7522 NB Enschede, The Netherlands; (M.J.A.M.v.P.); (J.H.)
| | - Christine R. Rose
- Institute of Neurobiology, Heinrich Heine University Düsseldorf, 40225 Düsseldorf, Germany;
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Yu X, Moye SL, Khakh BS. Local and CNS-Wide Astrocyte Intracellular Calcium Signaling Attenuation In Vivo with CalEx flox Mice. J Neurosci 2021; 41:4556-4574. [PMID: 33903221 PMCID: PMC8260243 DOI: 10.1523/jneurosci.0085-21.2021] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Revised: 03/21/2021] [Accepted: 03/30/2021] [Indexed: 01/12/2023] Open
Abstract
Astrocytes exist throughout the CNS and affect neural circuits and behavior through intracellular Ca2+ signaling. Studying the function(s) of astrocyte Ca2+ signaling has proven difficult because of the paucity of tools to achieve selective attenuation. Based on recent studies, we generated and used male and female knock-in mice for Cre-dependent expression of mCherry-tagged hPMCA2w/b to attenuate astrocyte Ca2+ signaling in genetically defined cells in vivo (CalExflox mice for Calcium Extrusion). We characterized CalExflox mice following local AAV-Cre microinjections into the striatum and found reduced astrocyte Ca2+ signaling (∼90%) accompanied with repetitive self-grooming behavior. We also crossed CalExflox mice to astrocyte-specific Aldh1l1-Cre/ERT2 mice to achieve inducible global CNS-wide Ca2+ signaling attenuation. Within 6 d of induction in the bigenic mice, we observed significantly altered ambulation in the open field, disrupted motor coordination and gait, and premature lethality. Furthermore, with histologic, imaging, and transcriptomic analyses, we identified cellular and molecular alterations in the cerebellum following mCherry-tagged hPMCA2w/b expression. Our data show that expression of mCherry-tagged hPMCA2w/b with CalExflox mice throughout the CNS resulted in substantial attenuation of astrocyte Ca2+ signaling and significant behavioral alterations in adult mice. We interpreted these findings candidly in relation to the ability of CalEx to attenuate astrocyte Ca2+ signaling, with regards to additional mechanistic interpretations of the data, and their relation to past studies that reduced astrocyte Ca2+ signaling throughout the CNS. The data and resources provide complementary ways to interrogate the function(s) of astrocytes in multiple experimental scenarios.SIGNIFICANCE STATEMENT Astrocytes represent a significant fraction of all brain cells and tile the entire central nervous system. Unlike neurons, astrocytes lack propagated electrical signals. Instead, astrocytes are proposed to use diverse and dynamic intracellular Ca2+ signals to communicate with other cells. An open question concerns if and how astrocyte Ca2+ signaling regulates behavior in adult mice. We approached this problem by generating a new transgenic mouse line to achieve inducible astrocyte Ca2+ signaling attenuation in vivo We report our data with this mouse line and we interpret the findings candidly in relation to past studies and within the framework of different mechanistic interpretations.
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Affiliation(s)
- Xinzhu Yu
- Department of Physiology
- Department of Molecular and Integrative Physiology, Beckman Institute, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801-3704
| | | | - Baljit S Khakh
- Department of Physiology
- Department of Neurobiology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California 90095-1751
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60
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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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61
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Neyrinck K, Van Den Daele J, Vervliet T, De Smedt J, Wierda K, Nijs M, Vanbokhoven T, D'hondt A, Planque M, Fendt SM, Shih PY, Seibt F, Almenar JP, Kreir M, Kumar D, Broccoli V, Bultynck G, Ebneth A, Cabrera-Socorro A, Verfaillie C. SOX9-induced Generation of Functional Astrocytes Supporting Neuronal Maturation in an All-human System. Stem Cell Rev Rep 2021; 17:1855-1873. [PMID: 33982246 PMCID: PMC8553725 DOI: 10.1007/s12015-021-10179-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/29/2021] [Indexed: 11/29/2022]
Abstract
Astrocytes, the main supportive cell type of the brain, show functional impairments upon ageing and in a broad spectrum of neurological disorders. Limited access to human astroglia for pre-clinical studies has been a major bottleneck delaying our understanding of their role in brain health and disease. We demonstrate here that functionally mature human astrocytes can be generated by SOX9 overexpression for 6 days in pluripotent stem cell (PSC)-derived neural progenitor cells. Inducible (i)SOX9-astrocytes display functional properties comparable to primary human astrocytes comprising glutamate uptake, induced calcium responses and cytokine/growth factor secretion. Importantly, electrophysiological properties of iNGN2-neurons co-cultured with iSOX9-astrocytes are indistinguishable from gold-standard murine primary cultures. The high yield, fast timing and the possibility to cryopreserve iSOX9-astrocytes without losing functional properties makes them suitable for scaled-up production for high-throughput analyses. Our findings represent a step forward to an all-human iPSC-derived neural model for drug development in neuroscience and towards the reduction of animal use in biomedical research.
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Affiliation(s)
- Katrien Neyrinck
- Stem Cell Institute, Department of Development and Regeneration, KU Leuven, Leuven, 3000, Belgium.
| | - Johanna Van Den Daele
- Stem Cell Institute, Department of Development and Regeneration, KU Leuven, Leuven, 3000, Belgium.
| | - Tim Vervliet
- Laboratory of Molecular and Cellular Signalling, Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium
| | - Jonathan De Smedt
- Stem Cell Institute, Department of Development and Regeneration, KU Leuven, Leuven, 3000, Belgium
| | - Keimpe Wierda
- Electrophysiology Expert Unit, VIB-KU Leuven Center for Brain & Disease Research, Leuven, 3000, Belgium
| | - Melissa Nijs
- Stem Cell Institute, Department of Development and Regeneration, KU Leuven, Leuven, 3000, Belgium
| | - Tom Vanbokhoven
- Stem Cell Institute, Department of Development and Regeneration, KU Leuven, Leuven, 3000, Belgium
| | - Astrid D'hondt
- Stem Cell Institute, Department of Development and Regeneration, KU Leuven, Leuven, 3000, Belgium
| | - Mélanie Planque
- Laboratory of Cellular Metabolism and Metabolic Regulation, Department of Oncoloy, KU Leuven and Leuven Cancer Institute (LKI), Leuven, 3000, Belgium
- Laboratory of Cellular Metabolism and Metabolic Regulation, VIB-KU Leuven Center for Cancer Biology, VIB, Leuven, 3000, Belgium
| | - Sarah-Maria Fendt
- Laboratory of Cellular Metabolism and Metabolic Regulation, Department of Oncoloy, KU Leuven and Leuven Cancer Institute (LKI), Leuven, 3000, Belgium
- Laboratory of Cellular Metabolism and Metabolic Regulation, VIB-KU Leuven Center for Cancer Biology, VIB, Leuven, 3000, Belgium
| | - Pei-Yu Shih
- Division of Janssen Pharmaceutica, Janssen Research & Development, Beerse, 2340, Belgium
| | - Frederik Seibt
- Division of Janssen Pharmaceutica, Janssen Research & Development, Beerse, 2340, Belgium
| | - Juan Pita Almenar
- Division of Janssen Pharmaceutica, Janssen Research & Development, Beerse, 2340, Belgium
| | - Mohamed Kreir
- Division of Janssen Pharmaceutica, Janssen Research & Development, Beerse, 2340, Belgium
| | - Devesh Kumar
- Division of Janssen Pharmaceutica, Janssen Research & Development, Beerse, 2340, Belgium
| | - Vania Broccoli
- Division of Neuroscience, IRCCS, San Raffaele Scientific Hospital, 20132, Milan, Italy
- Institute of Neuroscience, National Research Council (CNR), 20129, Milan, Italy
| | - Geert Bultynck
- Laboratory of Molecular and Cellular Signalling, Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium
| | - Andreas Ebneth
- Division of Janssen Pharmaceutica, Janssen Research & Development, Beerse, 2340, Belgium
| | | | - Catherine Verfaillie
- Stem Cell Institute, Department of Development and Regeneration, KU Leuven, Leuven, 3000, Belgium.
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62
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McCann MS, Maguire-Zeiss KA. Environmental toxicants in the brain: A review of astrocytic metabolic dysfunction. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2021; 84:103608. [PMID: 33556584 DOI: 10.1016/j.etap.2021.103608] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Revised: 01/24/2021] [Accepted: 01/29/2021] [Indexed: 06/12/2023]
Abstract
Exposure to environmental toxicants is linked to long-term adverse outcomes in the brain and involves the dysfunction of glial and neuronal cells. Astrocytes, the most numerous cell type, are increasingly implicated in the pathogenesis of many diseases of the central nervous system, including neurodegenerative diseases. Astrocytes are critical for proper brain function in part due to their robust antioxidant and unique metabolic capabilities. Additionally, astrocytes are positioned both at the blood-brain barrier, where they are the primary responders to xenobiotic penetrance of the CNS, and at synapses where they are in close contact with neurons and synaptic machinery. While exposure to several classes of environmental toxicants, including chlorinated and fluorinated compounds, and trace metals, have been implicated in neurodegenerative diseases, their impact on astrocytes represents an important and growing field of research. Here, we review existing literature focused on the impact of a range of synthetic compounds on astrocytic function. We focus specifically on perturbed metabolic processes in response to these compounds and consider how perturbation of these pathways impacts disease pathogenesis.
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Affiliation(s)
- Mondona S McCann
- Interdisciplinary Program in Neuroscience, Georgetown University Medical Center, Washington, DC, 20057, United States.
| | - Kathleen A Maguire-Zeiss
- Interdisciplinary Program in Neuroscience, Georgetown University Medical Center, Washington, DC, 20057, United States; Department of Neuroscience, Georgetown University Medical Center, Washington, DC, 20057, United States
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63
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Choi JIV, Tchernookova BK, Kumar W, Kiedrowski L, Goeke C, Guizzetti M, Larson J, Kreitzer MA, Malchow RP. Extracellular ATP-Induced Alterations in Extracellular H + Fluxes From Cultured Cortical and Hippocampal Astrocytes. Front Cell Neurosci 2021; 15:640217. [PMID: 33994945 PMCID: PMC8120152 DOI: 10.3389/fncel.2021.640217] [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: 12/10/2020] [Accepted: 03/19/2021] [Indexed: 12/18/2022] Open
Abstract
Small alterations in the level of extracellular H+ can profoundly alter neuronal activity throughout the nervous system. In this study, self-referencing H+-selective microelectrodes were used to examine extracellular H+ fluxes from individual astrocytes. Activation of astrocytes cultured from mouse hippocampus and rat cortex with extracellular ATP produced a pronounced increase in extracellular H+ flux. The ATP-elicited increase in H+ flux appeared to be independent of bicarbonate transport, as ATP increased H+ flux regardless of whether the primary extracellular pH buffer was 26 mM bicarbonate or 1 mM HEPES, and persisted when atmospheric levels of CO2 were replaced by oxygen. Adenosine failed to elicit any change in extracellular H+ fluxes, and ATP-mediated increases in H+ flux were inhibited by the P2 inhibitors suramin and PPADS suggesting direct activation of ATP receptors. Extracellular ATP also induced an intracellular rise in calcium in cultured astrocytes, and ATP-induced rises in both calcium and H+ efflux were significantly attenuated when calcium re-loading into the endoplasmic reticulum was inhibited by thapsigargin. Replacement of extracellular sodium with choline did not significantly reduce the size of the ATP-induced increases in H+ flux, and the increases in H+ flux were not significantly affected by addition of EIPA, suggesting little involvement of Na+/H+ exchangers in ATP-elicited increases in H+ flux. Given the high sensitivity of voltage-sensitive calcium channels on neurons to small changes in levels of free H+, we hypothesize that the ATP-mediated extrusion of H+ from astrocytes may play a key role in regulating signaling at synapses within the nervous system.
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Affiliation(s)
- Ji-In Vivien Choi
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, IL, United States.,Stritch School of Medicine, Loyola University, Maywood, IL, United States
| | - Boriana K Tchernookova
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, IL, United States
| | - Wasan Kumar
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, IL, United States
| | - Lech Kiedrowski
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, IL, United States.,Spot Cells LLC, Chicago, IL, United States
| | - Calla Goeke
- VA Portland Health Care System, Portland, OR, United States.,Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR, United States
| | - Marina Guizzetti
- VA Portland Health Care System, Portland, OR, United States.,Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR, United States
| | - John Larson
- Department of Psychiatry, University of Illinois at Chicago, Chicago, IL, United States
| | - Matthew A Kreitzer
- Department of Biology, Indiana Wesleyan University, Marion, IN, United States
| | - Robert Paul Malchow
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, IL, United States.,Department Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, IL, United States
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64
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Broadhead MJ, Miles GB. A common role for astrocytes in rhythmic behaviours? Prog Neurobiol 2021; 202:102052. [PMID: 33894330 DOI: 10.1016/j.pneurobio.2021.102052] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Revised: 03/03/2021] [Accepted: 04/13/2021] [Indexed: 01/16/2023]
Abstract
Astrocytes are a functionally diverse form of glial cell involved in various aspects of nervous system infrastructure, from the metabolic and structural support of neurons to direct neuromodulation of synaptic activity. Investigating how astrocytes behave in functionally related circuits may help us understand whether there is any conserved logic to the role of astrocytes within neuronal networks. Astrocytes are implicated as key neuromodulatory cells within neural circuits that control a number of rhythmic behaviours such as breathing, locomotion and circadian sleep-wake cycles. In this review, we examine the evidence that astrocytes are directly involved in the regulation of the neural circuits underlying six different rhythmic behaviours: locomotion, breathing, chewing, gastrointestinal motility, circadian sleep-wake cycles and oscillatory feeding behaviour. We discuss how astrocytes are integrated into the neuronal networks that regulate these behaviours, and identify the potential gliotransmission signalling mechanisms involved. From reviewing the evidence of astrocytic involvement in a range of rhythmic behaviours, we reveal a heterogenous array of gliotransmission mechanisms, which help to regulate neuronal networks. However, we also observe an intriguing thread of commonality, in the form of purinergic gliotransmission, which is frequently utilised to facilitate feedback inhibition within rhythmic networks to constrain a given behaviour within its operational range.
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Affiliation(s)
- Matthew J Broadhead
- School of Psychology and Neuroscience, University of St Andrews, St Andrews, UK.
| | - Gareth B Miles
- School of Psychology and Neuroscience, University of St Andrews, St Andrews, UK
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65
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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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66
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Vaidyanathan TV, Collard M, Yokoyama S, Reitman ME, Poskanzer KE. Cortical astrocytes independently regulate sleep depth and duration via separate GPCR pathways. eLife 2021; 10:63329. [PMID: 33729913 PMCID: PMC7968927 DOI: 10.7554/elife.63329] [Citation(s) in RCA: 66] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Accepted: 02/17/2021] [Indexed: 12/11/2022] Open
Abstract
Non-rapid eye movement (NREM) sleep, characterized by slow-wave electrophysiological activity, underlies several critical functions, including learning and memory. However, NREM sleep is heterogeneous, varying in duration, depth, and spatially across the cortex. While these NREM sleep features are thought to be largely independently regulated, there is also evidence that they are mechanistically coupled. To investigate how cortical NREM sleep features are controlled, we examined the astrocytic network, comprising a cortex-wide syncytium that influences population-level neuronal activity. We quantified endogenous astrocyte activity in mice over natural sleep and wake, then manipulated specific astrocytic G-protein-coupled receptor (GPCR) signaling pathways in vivo. We find that astrocytic Gi- and Gq-coupled GPCR signaling separately control NREM sleep depth and duration, respectively, and that astrocytic signaling causes differential changes in local and remote cortex. These data support a model in which the cortical astrocyte network serves as a hub for regulating distinct NREM sleep features. Sleep has many roles, from strengthening new memories to regulating mood and appetite. While we might instinctively think of sleep as a uniform state of reduced brain activity, the reality is more complex. First, over the course of the night, we cycle between a number of different sleep stages, which reflect different levels of sleep depth. Second, the amount of sleep depth is not necessarily even across the brain but can vary between regions. These sleep stages consist of either rapid eye movement (REM) sleep or non-REM (NREM) sleep. REM sleep is when most dreaming occurs, whereas NREM sleep is particularly important for learning and memory and can vary in duration and depth. During NREM sleep, large groups of neurons synchronize their firing to create rhythmic waves of activity known as slow waves. The more synchronous the activity, the deeper the sleep. Vaidyanathan et al. now show that brain cells called astrocytes help regulate NREM sleep. Astrocytes are not neurons but belong to a group of specialized cells called glia. They are the largest glia cell type in the brain and display an array of proteins on their surfaces called G-protein-coupled receptors (GPCRs). These enable them to sense sleep-wake signals from other parts of the brain and to generate their own signals. In fact, each astrocyte can communicate with thousands of neurons at once. They are therefore well-poised to coordinate brain activity during NREM sleep. Using innovative tools, Vaidyanathan et al. visualized astrocyte activity in mice as the animals woke up or fell asleep. The results showed that astrocytes change their activity just before each sleep–wake transition. They also revealed that astrocytes control both the depth and duration of NREM sleep via two different types of GPCR signals. Increasing one of these signals (Gi-GPCR) made the mice sleep more deeply but did not change sleep duration. Decreasing the other (Gq-GPCR) made the mice sleep for longer but did not affect sleep depth. Sleep problems affect many people at some point in their lives, and often co-exist with other conditions such as mental health disorders. Understanding how the brain regulates different features of sleep could help us develop better – and perhaps more specific – treatments for sleep disorders. The current study suggests that manipulating GPCRs on astrocytes might increase sleep depth, for example. But before work to test this idea can begin, we must first determine whether findings from sleeping mice also apply to people.
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Affiliation(s)
- Trisha V Vaidyanathan
- Neuroscience Graduate Program, University of California, San Francisco, San Francisco, United States.,Department of Biochemistry & Biophysics, University of California, San Francisco, San Francisco, United States
| | - Max Collard
- Neuroscience Graduate Program, University of California, San Francisco, San Francisco, United States
| | - Sae Yokoyama
- Department of Biochemistry & Biophysics, University of California, San Francisco, San Francisco, United States
| | - Michael E Reitman
- Neuroscience Graduate Program, University of California, San Francisco, San Francisco, United States.,Department of Biochemistry & Biophysics, University of California, San Francisco, San Francisco, United States
| | - Kira E Poskanzer
- Neuroscience Graduate Program, University of California, San Francisco, San Francisco, United States.,Department of Biochemistry & Biophysics, University of California, San Francisco, San Francisco, United States.,Kavli Institute for Fundamental Neuroscience, San Francisco, United States
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67
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Kronschläger MT, Siegert ASM, Resch FJ, Rajendran PS, Khakh BS, Sandkühler J. Lamina-specific properties of spinal astrocytes. Glia 2021; 69:1749-1766. [PMID: 33694249 PMCID: PMC8252791 DOI: 10.1002/glia.23990] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Revised: 02/24/2021] [Accepted: 02/26/2021] [Indexed: 12/19/2022]
Abstract
Astrocytes are indispensable for proper neuronal functioning. Given the diverse needs of neuronal circuits and the variety of tasks astrocytes perform, the perceived homogeneous nature of astrocytes has been questioned. In the spinal dorsal horn, complex neuronal circuitries regulate the integration of sensory information of different modalities. The dorsal horn is organized in a distinct laminar manner based on termination patterns of high‐ and low‐threshold afferent fibers and neuronal properties. Neurons in laminae I (L1) and II (L2) integrate potentially painful, nociceptive information, whereas neurons in lamina III (L3) and deeper laminae integrate innocuous, tactile information from the periphery. Sensory information is also integrated by an uncharacterized network of astrocytes. How these lamina‐specific characteristics of neuronal circuits of the dorsal horn are of functional importance for properties of astrocytes is currently unknown. We addressed if astrocytes in L1, L2, and L3 of the upper dorsal horn of mice are differentially equipped for the needs of neuronal circuits that process sensory information of different modalities. We found that astrocytes in L1 and L2 were characterized by a higher density, higher expression of GFAP, Cx43, and GLAST and a faster coupling speed than astrocytes located in L3. L1 astrocytes were more responsive to Kir4.1 blockade and had higher levels of AQP4 compared to L3 astrocytes. In contrast, basic membrane properties, network formation, and somatic intracellular calcium signaling were similar in L1–L3 astrocytes. Our data indicate that the properties of spinal astrocytes are fine‐tuned for the integration of nociceptive versus tactile information.
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Affiliation(s)
- Mira T Kronschläger
- Department of Neurophysiology, Center for Brain Research, Medical University of Vienna, Vienna, Austria.,Department of Physiology, David Geffen Schoof of Medicine, University of California Los Angeles, Los Angeles, California, USA
| | - Anna S M Siegert
- Department of Neurophysiology, Center for Brain Research, Medical University of Vienna, Vienna, Austria
| | - Felix J Resch
- Department of Neurophysiology, Center for Brain Research, Medical University of Vienna, Vienna, Austria
| | - Pradeep S Rajendran
- UCLA Cardiac Arrhythmia Center, Neurocardiology Research Program of Excellence, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, USA
| | - Baljit S Khakh
- Department of Physiology, David Geffen Schoof of Medicine, University of California Los Angeles, Los Angeles, California, USA
| | - Jürgen Sandkühler
- Department of Neurophysiology, Center for Brain Research, Medical University of Vienna, Vienna, Austria
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68
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Fabbri R, Saracino E, Treossi E, Zamboni R, Palermo V, Benfenati V. Graphene glial-interfaces: challenges and perspectives. NANOSCALE 2021; 13:4390-4407. [PMID: 33599662 DOI: 10.1039/d0nr07824g] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Graphene nanosheets are mechanically strong but flexible, electrically conductive and bio-compatible. Thus, due to these unique properties, they are being intensively studied as materials for the next generation of neural interfaces. Most of the literature focused on optimizing the interface between these materials and neurons. However, one of the most common causes of implant failure is the adverse inflammatory reaction of glial cells. These cells are not, as previously considered, just passive and supportive cells, but play a crucial role in the physiology and pathology of the nervous system, and in the interaction with implanted electrodes. Besides providing structural support to neurons, glia are responsible for the modulation of synaptic transmission and control of central and peripheral homeostasis. Accordingly, knowledge on the interaction between glia and biomaterials is essential to develop new implant-based therapies for the treatment of neurological disorders, such as epilepsy, brain tumours, and Alzheimer's and Parkinson's disease. This work provides an overview of the emerging literature on the interaction of graphene-based materials with glial cells, together with a complete description of the different types of glial cells and problems associated with them. We believe that this description will be important for researchers working in materials science and nanotechnology to develop new active materials to interface, measure and stimulate these cells.
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Affiliation(s)
- Roberta Fabbri
- Consiglio Nazionale delle Ricerche, Istituto per la Sintesi Organica e la Fotoreattività (CNR-ISOF), via Piero Gobetti 101, 40129 Bologna, Italy.
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69
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Abrego L, Gordleeva S, Kanakov O, Krivonosov M, Zaikin A. Estimating integrated information in bidirectional neuron-astrocyte communication. Phys Rev E 2021; 103:022410. [PMID: 33736090 DOI: 10.1103/physreve.103.022410] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Accepted: 01/04/2021] [Indexed: 01/14/2023]
Abstract
There is growing evidence that suggests the importance of astrocytes as elements for neural information processing through the modulation of synaptic transmission. A key aspect of this problem is understanding the impact of astrocytes in the information carried by compound events in neurons across time. In this paper, we investigate how the astrocytes participate in the information integrated by individual neurons in an ensemble through the measurement of "integrated information." We propose a computational model that considers bidirectional communication between astrocytes and neurons through glutamate-induced calcium signaling. Our model highlights the role of astrocytes in information processing through dynamical coordination. Our findings suggest that the astrocytic feedback promotes synergetic influences in the neural communication, which is maximized when there is a balance between excess correlation and spontaneous spiking activity. The results were further linked with additional measures such as net synergy and mutual information. This result reinforces the idea that astrocytes have integrative properties in communication among neurons.
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Affiliation(s)
- Luis Abrego
- Department of Mathematics, University College London, London, United Kingdom
| | - Susanna Gordleeva
- Neuroscience and Cognitive Technology Laboratory, Center for Technologies in Robotics and Mechatronics Components, Innopolis University, Innopolis, Russia
- Lobachevsky State University of Nizhny Novgorod, Nizhny Novgorod, Russia
| | - Oleg Kanakov
- Lobachevsky State University of Nizhny Novgorod, Nizhny Novgorod, Russia
| | - Mikhail Krivonosov
- Lobachevsky State University of Nizhny Novgorod, Nizhny Novgorod, Russia
| | - Alexey Zaikin
- Department of Mathematics, University College London, London, United Kingdom
- Lobachevsky State University of Nizhny Novgorod, Nizhny Novgorod, Russia
- Institute for Women's Health, University College London, London WC1E 6BT, United Kingdom
- Centre for Analysis of Complex Systems, Sechenov First Moscow State Medical University (Sechenov University), Moscow, Russia
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70
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Nguyen H, Zerimech S, Baltan S. Astrocyte Mitochondria in White-Matter Injury. Neurochem Res 2021; 46:2696-2714. [PMID: 33527218 DOI: 10.1007/s11064-021-03239-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 01/05/2021] [Accepted: 01/06/2021] [Indexed: 12/11/2022]
Abstract
This review summarizes the diverse structure and function of astrocytes to describe the bioenergetic versatility required of astrocytes that are situated at different locations. The intercellular domain of astrocyte mitochondria defines their roles in supporting and regulating astrocyte-neuron coupling and survival against ischemia. The heterogeneity of astrocyte mitochondria, and how subpopulations of astrocyte mitochondria adapt to interact with other glia and regulate axon function, require further investigation. It has become clear that mitochondrial permeability transition pores play a key role in a wide variety of human diseases, whose common pathology may be based on mitochondrial dysfunction triggered by Ca2+ and potentiated by oxidative stress. Reactive oxygen species cause axonal degeneration and a reduction in axonal transport, leading to axonal dystrophies and neurodegeneration including Alzheimer's disease, amyotrophic lateral sclerosis, Parkinson's disease, and Huntington's disease. Developing new tools to allow better investigation of mitochondrial structure and function in astrocytes, and techniques to specifically target astrocyte mitochondria, can help to unravel the role of mitochondrial health and dysfunction in a more inclusive context outside of neuronal cells. Overall, this review will assess the value of astrocyte mitochondria as a therapeutic target to mitigate acute and chronic injury in the CNS.
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Affiliation(s)
- Hung Nguyen
- Anesthesiology and Peri-Operative Medicine (APOM), Oregon Health and Science University, Portland, OR, 97239, USA
| | - Sarah Zerimech
- Anesthesiology and Peri-Operative Medicine (APOM), Oregon Health and Science University, Portland, OR, 97239, USA
| | - Selva Baltan
- Anesthesiology and Peri-Operative Medicine (APOM), Oregon Health and Science University, Portland, OR, 97239, USA.
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71
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Yanpallewar S, Fulgenzi G, Tomassoni-Ardori F, Barrick C, Tessarollo L. Delayed onset of inherited ALS by deletion of the BDNF receptor TrkB.T1 is non-cell autonomous. Exp Neurol 2020; 337:113576. [PMID: 33359475 DOI: 10.1016/j.expneurol.2020.113576] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2020] [Revised: 12/04/2020] [Accepted: 12/21/2020] [Indexed: 12/18/2022]
Abstract
The pathophysiology of Amyotrophic Lateral Sclerosis (ALS), a disease caused by the gradual degeneration of motoneurons, is still largely unknown. Insufficient neurotrophic support has been cited as one of the causes of motoneuron cell death. Neurotrophic factors such as BDNF have been evaluated in ALS human clinical trials, but yielded disappointing results attributed to the poor pharmacokinetics and pharmacodynamics of BDNF. In the inherited ALS G93A SOD1 animal model, deletion of the BDNF receptor TrkB.T1 delays spinal cord motoneuron cell death and muscle weakness through an unknown cellular mechanism. Here we show that TrkB.T1 is expressed ubiquitously in the spinal cord and its deletion does not change the SOD1 mutant spinal cord inflammatory state suggesting that TrkB.T1 does not influence microglia or astrocyte activation. Although TrkB.T1 knockout in astrocytes preserves muscle strength and co-ordination at early stages of disease, its specific conditional deletion in motoneurons or astrocytes does not delay motoneuron cell death during the early stage of the disease. These data suggest that TrkB.T1 may limit the neuroprotective BDNF signaling to motoneurons via a non-cell autonomous mechanism providing new understanding into the reasons for past clinical failures and insights into the design of future clinical trials employing TrkB agonists in ALS.
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Affiliation(s)
| | - Gianluca Fulgenzi
- Neural Development Section, Mouse Cancer Genetics Program, CCR, NCI, NIH, USA
| | | | - Colleen Barrick
- Neural Development Section, Mouse Cancer Genetics Program, CCR, NCI, NIH, USA
| | - Lino Tessarollo
- Neural Development Section, Mouse Cancer Genetics Program, CCR, NCI, NIH, USA.
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72
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Dynamic Transitions in Neuronal Network Firing Sustained by Abnormal Astrocyte Feedback. Neural Plast 2020; 2020:8864246. [PMID: 33299401 PMCID: PMC7704208 DOI: 10.1155/2020/8864246] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Revised: 10/24/2020] [Accepted: 10/28/2020] [Indexed: 11/21/2022] Open
Abstract
Astrocytes play a crucial role in neuronal firing activity. Their abnormal state may lead to the pathological transition of neuronal firing patterns and even induce seizures. However, there is still little evidence explaining how the astrocyte network modulates seizures caused by structural abnormalities, such as gliosis. To explore the role of gliosis of the astrocyte network in epileptic seizures, we first established a direct astrocyte feedback neuronal network model on the basis of the hippocampal CA3 neuron-astrocyte model to simulate the condition of gliosis when astrocyte processes swell and the feedback to neurons increases in an abnormal state. We analyzed the firing pattern transitions of the neuronal network when astrocyte feedback starts to change via increases in both astrocyte feedback intensity and the connection probability of astrocytes to neurons in the network. The results show that as the connection probability and astrocyte feedback intensity increase, neuronal firing transforms from a nonepileptic synchronous firing state to an asynchronous firing state, and when astrocyte feedback starts to become abnormal, seizure-like firing becomes more severe and synchronized; meanwhile, the synchronization area continues to expand and eventually transforms into long-term seizure-like synchronous firing. Therefore, our results prove that astrocyte feedback can regulate the firing of the neuronal network, and when the astrocyte network develops gliosis, there will be an increase in the induction rate of epileptic seizures.
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73
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das Neves SP, Sousa JC, Sousa N, Cerqueira JJ, Marques F. Altered astrocytic function in experimental neuroinflammation and multiple sclerosis. Glia 2020; 69:1341-1368. [PMID: 33247866 DOI: 10.1002/glia.23940] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Revised: 11/14/2020] [Accepted: 11/17/2020] [Indexed: 12/11/2022]
Abstract
Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system (CNS) that affects about 2.5 million people worldwide. In MS, the patients' immune system starts to attack the myelin sheath, leading to demyelination, neurodegeneration, and, ultimately, loss of vital neurological functions such as walking. There is currently no cure for MS and the available treatments only slow the initial phases of the disease. The later-disease mechanisms are poorly understood and do not directly correlate with the activity of immune system cells, the main target of the available treatments. Instead, evidence suggests that disease progression and disability are better correlated with the maintenance of a persistent low-grade inflammation inside the CNS, driven by local glial cells, like astrocytes and microglia. Depending on the context, astrocytes can (a) exacerbate inflammation or (b) promote immunosuppression and tissue repair. In this review, we will address the present knowledge that exists regarding the role of astrocytes in MS and experimental animal models of the disease.
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Affiliation(s)
- Sofia Pereira das Neves
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal.,ICVS/3B's - PT Government Associate Laboratory, Braga, Portugal
| | - João Carlos Sousa
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal.,ICVS/3B's - PT Government Associate Laboratory, Braga, Portugal
| | - Nuno Sousa
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal.,ICVS/3B's - PT Government Associate Laboratory, Braga, Portugal.,Clinical Academic Center, Braga, Portugal
| | - João José Cerqueira
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal.,ICVS/3B's - PT Government Associate Laboratory, Braga, Portugal.,Clinical Academic Center, Braga, Portugal
| | - Fernanda Marques
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal.,ICVS/3B's - PT Government Associate Laboratory, Braga, Portugal
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74
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Blum ID, Keleş MF, Baz ES, Han E, Park K, Luu S, Issa H, Brown M, Ho MCW, Tabuchi M, Liu S, Wu MN. Astroglial Calcium Signaling Encodes Sleep Need in Drosophila. Curr Biol 2020; 31:150-162.e7. [PMID: 33186550 DOI: 10.1016/j.cub.2020.10.012] [Citation(s) in RCA: 56] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 09/17/2020] [Accepted: 10/07/2020] [Indexed: 12/14/2022]
Abstract
Sleep is under homeostatic control, whereby increasing wakefulness generates sleep need and triggers sleep drive. However, the molecular and cellular pathways by which sleep need is encoded are poorly understood. In addition, the mechanisms underlying both how and when sleep need is transformed to sleep drive are unknown. Here, using ex vivo and in vivo imaging, we show in Drosophila that astroglial Ca2+ signaling increases with sleep need. We demonstrate that this signaling is dependent on a specific L-type Ca2+ channel and is necessary for homeostatic sleep rebound. Thermogenetically increasing Ca2+ in astrocytes induces persistent sleep behavior, and we exploit this phenotype to conduct a genetic screen for genes required for the homeostatic regulation of sleep. From this large-scale screen, we identify TyrRII, a monoaminergic receptor required in astrocytes for sleep homeostasis. TyrRII levels rise following sleep deprivation in a Ca2+-dependent manner, promoting further increases in astrocytic Ca2+ and resulting in a positive-feedback loop. Moreover, our findings suggest that astrocytes then transmit this sleep need to a sleep drive circuit by upregulating and releasing the interleukin-1 analog Spätzle, which then acts on Toll receptors on R5 neurons. These findings define astroglial Ca2+ signaling mechanisms encoding sleep need and reveal dynamic properties of the sleep homeostatic control system.
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Affiliation(s)
- Ian D Blum
- Department of Neurology, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Mehmet F Keleş
- Department of Neurology, Johns Hopkins University, Baltimore, MD 21205, USA
| | - El-Sayed Baz
- VIB Center for Brain and Disease Research and Department of Neurosciences, KU Leuven, Leuven 3000, Belgium
| | - Emily Han
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Kristen Park
- Department of Neurology, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Skylar Luu
- Department of Neurology, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Habon Issa
- Department of Neurology, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Matt Brown
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Margaret C W Ho
- Department of Neurology, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Masashi Tabuchi
- Department of Neurology, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Sha Liu
- VIB Center for Brain and Disease Research and Department of Neurosciences, KU Leuven, Leuven 3000, Belgium.
| | - Mark N Wu
- Department of Neurology, Johns Hopkins University, Baltimore, MD 21205, USA; Solomon H. Snyder Department of Neuroscience, Johns Hopkins University, Baltimore, MD 21205, USA.
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75
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Purinergic signaling orchestrating neuron-glia communication. Pharmacol Res 2020; 162:105253. [PMID: 33080321 DOI: 10.1016/j.phrs.2020.105253] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Revised: 09/29/2020] [Accepted: 10/09/2020] [Indexed: 12/12/2022]
Abstract
This review discusses the evidence supporting a role for ATP signaling (operated by P2X and P2Y receptors) and adenosine signaling (mainly operated by A1 and A2A receptors) in the crosstalk between neurons, astrocytes, microglia and oligodendrocytes. An initial emphasis will be given to the cooperation between adenosine receptors to sharpen information salience encoding across synapses. The interplay between ATP and adenosine signaling in the communication between astrocytes and neurons will then be presented in context of the integrative properties of the astrocytic syncytium, allowing to implement heterosynaptic depression processes in neuronal networks. The process of microglia 'activation' and its control by astrocytes and neurons will then be analyzed under the perspective of an interplay between different P2 receptors and adenosine A2A receptors. In spite of these indications of a prominent role of purinergic signaling in the bidirectional communication between neurons and glia, its therapeutical exploitation still awaits obtaining an integrated view of the spatio-temporal action of ATP signaling and adenosine signaling, clearly distinguishing the involvement of both purinergic signaling systems in the regulation of physiological processes and in the control of pathogenic-like responses upon brain dysfunction or damage.
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76
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Cho J, Huh Y. Astrocytic Calcium Dynamics Along the Pain Pathway. Front Cell Neurosci 2020; 14:594216. [PMID: 33192331 PMCID: PMC7596274 DOI: 10.3389/fncel.2020.594216] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Accepted: 09/14/2020] [Indexed: 12/30/2022] Open
Abstract
Astrocytes, once thought to be passive cells merely filling the space between neurons in the nervous system, are receiving attention as active modulators of the brain and spinal cord physiology by providing nutrients, maintaining homeostasis, and modulating synaptic transmission. Accumulating evidence indicates that astrocytes are critically involved in chronic pain regulation. Injury induces astrocytes to become reactive, and recent studies suggest that reactive astrocytes can have either neuroprotective or neurodegenerative effects. While the exact mechanisms underlying the transition from resting astrocytes to reactive astrocytes remain unknown, astrocytic calcium increase, coordinated by inflammatory molecules, has been suggested to trigger this transition. In this mini review article, we will discuss the roles of astrocytic calcium, channels contributing to calcium dynamics in astrocytes, astrocyte activations along the pain pathway, and possible relationships between astrocytic calcium dynamics and chronic pain.
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Affiliation(s)
- Jeiwon Cho
- Brain and Cognitive Science, Scranton College, Ewha Womans University, Seoul, South Korea
| | - Yeowool Huh
- Department of Medical Science, College of Medicine, Catholic Kwandong University, Incheon, South Korea.,Translational Brain Research Center, Catholic Kwandong University, International St. Mary's Hospital, Incheon, South Korea
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77
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Blood-brain barrier integrity in the pathogenesis of Alzheimer's disease. Front Neuroendocrinol 2020; 59:100857. [PMID: 32781194 DOI: 10.1016/j.yfrne.2020.100857] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Revised: 07/27/2020] [Accepted: 07/29/2020] [Indexed: 02/06/2023]
Abstract
The blood-brain barrier (BBB) tightly controls the molecular exchange between the brain parenchyma and blood. Accumulated evidence from transgenic animal Alzheimer's disease (AD) models and human AD patients have demonstrated that BBB dysfunction is a major player in AD pathology. In this review, we discuss the role of the BBB in maintaining brain integrity and how this is mediated by crosstalk between BBB-associated cells within the neurovascular unit (NVU). We then discuss the role of the NVU, in particular its endothelial cell, pericyte, and glial cell constituents, in AD pathogenesis. The effect of substances released by the neuroendocrine system in modulating BBB function and AD pathogenesis is also discussed. We perform a systematic review of currently available AD treatments specifically targeting pericytes and BBB glial cells. In summary, this review provides a comprehensive overview of BBB dysfunction in AD and a new perspective on the development of therapeutics for AD.
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78
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Falcone C, Penna E, Hong T, Tarantal AF, Hof PR, Hopkins WD, Sherwood CC, Noctor SC, Martínez-Cerdeño V. Cortical Interlaminar Astrocytes Are Generated Prenatally, Mature Postnatally, and Express Unique Markers in Human and Nonhuman Primates. Cereb Cortex 2020; 31:379-395. [PMID: 32930323 DOI: 10.1093/cercor/bhaa231] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Revised: 07/27/2020] [Accepted: 07/27/2020] [Indexed: 02/07/2023] Open
Abstract
Interlaminar astrocytes (ILAs) are a subset of cortical astrocytes that reside in layer I, express GFAP, have a soma contacting the pia, and contain long interlaminar processes that extend through several cortical layers. We studied the prenatal and postnatal development of ILAs in three species of primates (rhesus macaque, chimpanzee, and human). We found that ILAs are generated prenatally likely from radial glial (RG) cells, that ILAs proliferate locally during gestation, and that ILAs extend interlaminar processes during postnatal stages of development. We showed that the density and morphological complexity of ILAs increase with age, and that ILAs express multiple markers that are expressed by RG cells (Pax6, Sox2, and Nestin), specific to inner and outer RG cells (Cryab and Hopx), and astrocyte markers (S100β, Aqp4, and GLAST) in prenatal stages and in adult. Finally, we demonstrated that rudimentary ILAs in mouse also express the RG markers Pax6, Sox2, and Nestin, but do not express S100β, Cryab, or Hopx, and that the density and morphological complexity of ILAs differ between primate species and mouse. Together these findings contribute new information on astrogenesis of this unique class of cells and suggest a lineal relationship between RG cells and ILAs.
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Affiliation(s)
- Carmen Falcone
- Department of Pathology and Laboratory Medicine, UC Davis School of Medicine, Sacramento, CA 95817, USA.,Institute for Pediatric Regenerative Medicine, and Shriners Hospitals, Sacramento, CA 95817, USA
| | - Elisa Penna
- MIND Institute, UC Davis School of Medicine, Sacramento, CA 95817, USA.,Department of Psychiatry and Behavioral Sciences, UC Davis School of Medicine, Sacramento, CA 95817, USA
| | - Tiffany Hong
- Department of Pathology and Laboratory Medicine, UC Davis School of Medicine, Sacramento, CA 95817, USA.,Institute for Pediatric Regenerative Medicine, and Shriners Hospitals, Sacramento, CA 95817, USA
| | - Alice F Tarantal
- Departments of Pediatrics and Cell Biology and Human Anatomy, and California National Primate Research Center, University of California, Davis, CA 95616, USA
| | - Patrick R Hof
- Nash Family Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - William D Hopkins
- Department of Comparative Medicine, Keeling Center for Comparative Medicine and Research, The University of Texas MD Anderson Cancer Center, Bastrop, TX 78602, USA
| | - Chet C Sherwood
- Department of Anthropology and Center for the Advanced Study of Human Paleobiology, The George Washington University, Washington, DC 20052, USA
| | - Stephen C Noctor
- MIND Institute, UC Davis School of Medicine, Sacramento, CA 95817, USA.,Department of Psychiatry and Behavioral Sciences, UC Davis School of Medicine, Sacramento, CA 95817, USA
| | - Verónica Martínez-Cerdeño
- Department of Pathology and Laboratory Medicine, UC Davis School of Medicine, Sacramento, CA 95817, USA.,Institute for Pediatric Regenerative Medicine, and Shriners Hospitals, Sacramento, CA 95817, USA.,MIND Institute, UC Davis School of Medicine, Sacramento, CA 95817, USA
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79
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Zhang RW, Du WJ, Prober DA, Du JL. Müller Glial Cells Participate in Retinal Waves via Glutamate Transporters and AMPA Receptors. Cell Rep 2020; 27:2871-2880.e2. [PMID: 31167134 PMCID: PMC6659749 DOI: 10.1016/j.celrep.2019.05.011] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Revised: 02/21/2019] [Accepted: 04/30/2019] [Indexed: 12/26/2022] Open
Abstract
Retinal waves, the spontaneous patterned neural activities propagating among developing retinal ganglion cells (RGCs), instruct the activity-dependent refinement of visuotopic maps. Although it is known that the wave is initiated successively by amacrine cells and bipolar cells, the behavior and function of glia in retinal waves remain unclear. Using multiple in vivo methods in larval zebrafish, we found that Müller glial cells (MGCs) display wave-like spontaneous activities, which start at MGC processes within the inner plexiform layer, vertically spread to their somata and endfeet, and horizontally propagate into neighboring MGCs. MGC waves depend on glutamatergic signaling derived from bipolar cells. Moreover, MGCs express both glia-specific glutamate transporters and the AMPA subtype of glutamate receptors. The AMPA receptors mediate MGC calcium activities during retinal waves, whereas the glutamate transporters modulate the occurrence of retinal waves. Thus, MGCs can sense and regulate retinal waves via AMPA receptors and glutamate transporters, respectively.
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Affiliation(s)
- Rong-Wei Zhang
- Institute of Neuroscience, State Key Laboratory of Neuroscience, Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, 320 Yue-Yang Road, Shanghai 200031, China.
| | - Wen-Jie Du
- Institute of Neuroscience, State Key Laboratory of Neuroscience, Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, 320 Yue-Yang Road, Shanghai 200031, China
| | - David A Prober
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Jiu-Lin Du
- Institute of Neuroscience, State Key Laboratory of Neuroscience, Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, 320 Yue-Yang Road, Shanghai 200031, China; School of Life Science and Technology, ShanghaiTech University, 319 Yue-Yang Road, Shanghai 200031, China; School of Future Technology, University of Chinese Academy of Sciences, 19A Yu-Quan Road, Beijing 100049, China.
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80
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Long-Term Impact of Early-Life Stress on Hippocampal Plasticity: Spotlight on Astrocytes. Int J Mol Sci 2020; 21:ijms21144999. [PMID: 32679826 PMCID: PMC7404101 DOI: 10.3390/ijms21144999] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Revised: 07/10/2020] [Accepted: 07/13/2020] [Indexed: 12/15/2022] Open
Abstract
Adverse experiences during childhood are among the most prominent risk factors for developing mood and anxiety disorders later in life. Early-life stress interventions have been established as suitable models to study the neurobiological basis of childhood adversity in rodents. Different models such as maternal separation, impaired maternal care and juvenile stress during the postweaning/prepubertal life phase are utilized. Especially within the limbic system, they induce lasting alterations in neuronal circuits, neurotransmitter systems, neuronal architecture and plasticity that are further associated with emotional and cognitive information processing. Recent studies found that astrocytes, a special group of glial cells, have altered functions following early-life stress as well. As part of the tripartite synapse, astrocytes interact with neurons in multiple ways by affecting neurotransmitter uptake and metabolism, by providing gliotransmitters and by providing energy to neurons within local circuits. Thus, astrocytes comprise powerful modulators of neuronal plasticity and are well suited to mediate the long-term effects of early-life stress on neuronal circuits. In this review, we will summarize current findings on altered astrocyte function and hippocampal plasticity following early-life stress. Highlighting studies for astrocyte-related plasticity modulation as well as open questions, we will elucidate the potential of astrocytes as new targets for interventions against stress-induced neuropsychiatric disorders.
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81
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Pham C, Moro DH, Mouffle C, Didienne S, Hepp R, Pfrieger FW, Mangin JM, Legendre P, Martin C, Luquet S, Cauli B, Li D. Mapping astrocyte activity domains by light sheet imaging and spatio-temporal correlation screening. Neuroimage 2020; 220:117069. [PMID: 32585347 DOI: 10.1016/j.neuroimage.2020.117069] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Revised: 06/12/2020] [Accepted: 06/15/2020] [Indexed: 02/08/2023] Open
Abstract
Astrocytes are a major type of glial cell in the mammalian brain, essentially regulating neuronal development and function. Quantitative imaging represents an important approach to study astrocytic signaling in neural circuits. Focusing on astrocytic Ca2+ activity, a key pathway implicated in astrocye-neuron interaction, we here report a strategy combining fast light sheet fluorescence microscopy (LSFM) and correlative screening-based time series analysis, to map activity domains in astrocytes in living mammalian nerve tissue. Light sheet of micron-scale thickness enables wide-field optical sectioning to image astrocytes in acute mouse brain slices. Using both chemical and genetically encoded Ca2+ indicators, we demonstrate the complementary advantages of LSFM in mapping Ca2+ domains in astrocyte populations as compared to epifluorescence and two-photon microscopy. Our approach then revealed distinct kinetics of Ca2+ signals between cortical and hypothalamic astrocytes in resting conditions and following the activation of adrenergic G protein coupled receptor (GPCR). This observation highlights the activity heterogeneity across regionally distinct astrocyte populations, and indicates the potential of our method for investigating dynamic signals in astrocytes.
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Affiliation(s)
- Cuong Pham
- Sorbonne Université, Institute of Biology Paris Seine, Neuroscience Paris Seine, CNRS UMR8246, INSERM U1130, UPMC UMCR18, Paris, 75005, France
| | - Daniela Herrera Moro
- Unité de Biologie Fonctionnelle et Adaptative, Centre National la Recherche Scientifique, Unité Mixte de Recherche 8251, Université Paris Diderot, Sorbonne Paris Cité, 75205, Paris, France
| | - Christine Mouffle
- Sorbonne Université, Institute of Biology Paris Seine, Neuroscience Paris Seine, CNRS UMR8246, INSERM U1130, UPMC UMCR18, Paris, 75005, France
| | - Steve Didienne
- Sorbonne Université, Institute of Biology Paris Seine, Neuroscience Paris Seine, CNRS UMR8246, INSERM U1130, UPMC UMCR18, Paris, 75005, France
| | - Régine Hepp
- Sorbonne Université, Institute of Biology Paris Seine, Neuroscience Paris Seine, CNRS UMR8246, INSERM U1130, UPMC UMCR18, Paris, 75005, France
| | - Frank W Pfrieger
- Centre National de la Recherche Scientifique, Université de Strasbourg, Institut des Neurosciences Cellulaires et Intégratives, F-67000, Strasbourg, France
| | - Jean-Marie Mangin
- Sorbonne Université, Institute of Biology Paris Seine, Neuroscience Paris Seine, CNRS UMR8246, INSERM U1130, UPMC UMCR18, Paris, 75005, France
| | - Pascal Legendre
- Sorbonne Université, Institute of Biology Paris Seine, Neuroscience Paris Seine, CNRS UMR8246, INSERM U1130, UPMC UMCR18, Paris, 75005, France
| | - Claire Martin
- Unité de Biologie Fonctionnelle et Adaptative, Centre National la Recherche Scientifique, Unité Mixte de Recherche 8251, Université Paris Diderot, Sorbonne Paris Cité, 75205, Paris, France
| | - Serge Luquet
- Unité de Biologie Fonctionnelle et Adaptative, Centre National la Recherche Scientifique, Unité Mixte de Recherche 8251, Université Paris Diderot, Sorbonne Paris Cité, 75205, Paris, France
| | - Bruno Cauli
- Sorbonne Université, Institute of Biology Paris Seine, Neuroscience Paris Seine, CNRS UMR8246, INSERM U1130, UPMC UMCR18, Paris, 75005, France
| | - Dongdong Li
- Sorbonne Université, Institute of Biology Paris Seine, Neuroscience Paris Seine, CNRS UMR8246, INSERM U1130, UPMC UMCR18, Paris, 75005, France.
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82
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Gaidin SG, Zinchenko VP, Sergeev AI, Teplov IY, Mal'tseva VN, Kosenkov AM. Activation of alpha‐2 adrenergic receptors stimulates GABA release by astrocytes. Glia 2020; 68:1114-1130. [DOI: 10.1002/glia.23763] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2019] [Revised: 11/26/2019] [Accepted: 12/03/2019] [Indexed: 11/08/2022]
Affiliation(s)
- Sergei G. Gaidin
- Institute of Cell Biophysics of the Russian Academy of Sciences, Federal Research Center “Pushchino Scientific Center for Biological Research of the Russian Academy of Sciences” Pushchino Russia
| | - Valery P. Zinchenko
- Institute of Cell Biophysics of the Russian Academy of Sciences, Federal Research Center “Pushchino Scientific Center for Biological Research of the Russian Academy of Sciences” Pushchino Russia
| | - Alexander I. Sergeev
- Institute of Cell Biophysics of the Russian Academy of Sciences, Federal Research Center “Pushchino Scientific Center for Biological Research of the Russian Academy of Sciences” Pushchino Russia
| | - Ilia Y. Teplov
- Institute of Cell Biophysics of the Russian Academy of Sciences, Federal Research Center “Pushchino Scientific Center for Biological Research of the Russian Academy of Sciences” Pushchino Russia
| | - Valentina N. Mal'tseva
- Institute of Cell Biophysics of the Russian Academy of Sciences, Federal Research Center “Pushchino Scientific Center for Biological Research of the Russian Academy of Sciences” Pushchino Russia
| | - Artem M. Kosenkov
- Institute of Cell Biophysics of the Russian Academy of Sciences, Federal Research Center “Pushchino Scientific Center for Biological Research of the Russian Academy of Sciences” Pushchino Russia
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83
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Gollihue J, Norris C. Astrocyte mitochondria: Central players and potential therapeutic targets for neurodegenerative diseases and injury. Ageing Res Rev 2020; 59:101039. [PMID: 32105849 DOI: 10.1016/j.arr.2020.101039] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Revised: 01/23/2020] [Accepted: 02/23/2020] [Indexed: 01/16/2023]
Abstract
Mitochondrial function has long been the focus of many therapeutic strategies for ameliorating age-related neurodegeneration and cognitive decline. Historically, the role of mitochondria in non-neuronal cell types has been overshadowed by neuronal mitochondria, which are responsible for the bulk of oxidative metabolism in the brain. Despite this neuronal bias, mitochondrial function in glial cells, particularly astrocytes, is increasingly recognized to play crucial roles in overall brain metabolism, synaptic transmission, and neuronal protection. Changes in astrocytic mitochondrial function appear to be intimately linked to astrocyte activation/reactivity found in most all age-related neurodegenerative diseases. Here, we address the importance of mitochondrial function to astrocyte signaling and consider how mitochondria could contribute to both the detrimental and protective properties of activated astrocytes. Strategies for protecting astrocytic mitochondrial function, promoting bidirectional transfer of mitochondria between astrocytes and neurons, and transplanting healthy mitochondria to diseased nervous tissue are also discussed.
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84
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Giaume C, Naus CC, Sáez JC, Leybaert L. Glial Connexins and Pannexins in the Healthy and Diseased Brain. Physiol Rev 2020; 101:93-145. [PMID: 32326824 DOI: 10.1152/physrev.00043.2018] [Citation(s) in RCA: 75] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Over the past several decades a large amount of data have established that glial cells, the main cell population in the brain, dynamically interact with neurons and thus impact their activity and survival. One typical feature of glia is their marked expression of several connexins, the membrane proteins forming intercellular gap junction channels and hemichannels. Pannexins, which have a tetraspan membrane topology as connexins, are also detected in glial cells. Here, we review the evidence that connexin and pannexin channels are actively involved in dynamic and metabolic neuroglial interactions in physiological as well as in pathological situations. These features of neuroglial interactions open the way to identify novel non-neuronal aspects that allow for a better understanding of behavior and information processing performed by neurons. This will also complement the "neurocentric" view by facilitating the development of glia-targeted therapeutic strategies in brain disease.
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Affiliation(s)
- Christian Giaume
- Collège de France, Center for Interdisciplinary Research in Biology (CIRB)/Centre National de la Recherche Scientifique, Unité Mixte de Recherche 7241/Institut National de la Santé et de la Recherche Médicale U1050, Paris, France; University Pierre et Marie Curie, Paris, France; MEMOLIFE Laboratory of Excellence and Paris Science Lettre Research University, Paris, France; Department of Cellular & Physiological Sciences, Life Sciences Institute, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada; Departamento de Fisiología, Pontificia Universidad Católica de Chile, Santiago, Chile; Instituo de Neurociencias, Centro Interdisciplinario de Neurociencias, Universidad de Valparaíso, Valparaíso, Chile; Physiology Group, Department of Basic and Applied Medical Sciences, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium
| | - Christian C Naus
- Collège de France, Center for Interdisciplinary Research in Biology (CIRB)/Centre National de la Recherche Scientifique, Unité Mixte de Recherche 7241/Institut National de la Santé et de la Recherche Médicale U1050, Paris, France; University Pierre et Marie Curie, Paris, France; MEMOLIFE Laboratory of Excellence and Paris Science Lettre Research University, Paris, France; Department of Cellular & Physiological Sciences, Life Sciences Institute, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada; Departamento de Fisiología, Pontificia Universidad Católica de Chile, Santiago, Chile; Instituo de Neurociencias, Centro Interdisciplinario de Neurociencias, Universidad de Valparaíso, Valparaíso, Chile; Physiology Group, Department of Basic and Applied Medical Sciences, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium
| | - Juan C Sáez
- Collège de France, Center for Interdisciplinary Research in Biology (CIRB)/Centre National de la Recherche Scientifique, Unité Mixte de Recherche 7241/Institut National de la Santé et de la Recherche Médicale U1050, Paris, France; University Pierre et Marie Curie, Paris, France; MEMOLIFE Laboratory of Excellence and Paris Science Lettre Research University, Paris, France; Department of Cellular & Physiological Sciences, Life Sciences Institute, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada; Departamento de Fisiología, Pontificia Universidad Católica de Chile, Santiago, Chile; Instituo de Neurociencias, Centro Interdisciplinario de Neurociencias, Universidad de Valparaíso, Valparaíso, Chile; Physiology Group, Department of Basic and Applied Medical Sciences, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium
| | - Luc Leybaert
- Collège de France, Center for Interdisciplinary Research in Biology (CIRB)/Centre National de la Recherche Scientifique, Unité Mixte de Recherche 7241/Institut National de la Santé et de la Recherche Médicale U1050, Paris, France; University Pierre et Marie Curie, Paris, France; MEMOLIFE Laboratory of Excellence and Paris Science Lettre Research University, Paris, France; Department of Cellular & Physiological Sciences, Life Sciences Institute, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada; Departamento de Fisiología, Pontificia Universidad Católica de Chile, Santiago, Chile; Instituo de Neurociencias, Centro Interdisciplinario de Neurociencias, Universidad de Valparaíso, Valparaíso, Chile; Physiology Group, Department of Basic and Applied Medical Sciences, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium
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85
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Isolation, culture, and downstream characterization of primary microglia and astrocytes from adult rodent brain and spinal cord. J Neurosci Methods 2020; 340:108742. [PMID: 32315669 DOI: 10.1016/j.jneumeth.2020.108742] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Revised: 04/10/2020] [Accepted: 04/14/2020] [Indexed: 01/01/2023]
Abstract
BACKGROUND Neuroimmunologists aspire to understand the interactions between neurons, microglia, and astrocytes in the CNS. To study these cells, researchers work with either immortalized cell lines or primary cells acquired from animal tissue. Primary cells reflect in vivo characteristics and functionality compared to immortalized cells; however, they are challenging to acquire and maintain. NEW METHOD Established protocols to harvest primary glia use neonatal rodents, here we provide a method for simultaneously isolating microglia and astrocytes from brain and/or spinal cord from adult rodents. We utilized a discontinuous percoll density gradient enabling easy discrimination of these cell populations without enzymatic digestion or complex sorting techniques. RESULTS We found cells isolated from the percoll interface between 70 %-50 % were microglia, as they express ionizing calcium-binding adaptor molecule 1 (Iba1) in immunocytochemistry and CD11bhi and CD45lo using flow cytometry. Isolated cells from the 50 %-30 % interface were astrocytes as they express glial fibrillary acidic protein (GFAP) in immunocytochemistry and Glutamate aspartate transporter (GLAST)-1 using flow cytometry. Cultured microglia and astrocytes showed a functional increase in IL-6 production after treatment of lipopolysaccharide (LPS). COMPARISON WITH EXISTING METHODS Our method allows for rapid isolation of both microglia and astrocytes in one protocol with relatively few resources, preserves cellular phenotype, and yields high cell numbers without magnetic or antibody sorting. CONCLUSION Here we show a novel, single protocol to isolate microglia and astrocytes from brain and spinal cord tissue, allowing for culturing and other downstream applications from the cells of animals of various ages, which will be useful for researchers investigating these two major glial cell types from the brain or spinal cord of the same rodent.
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86
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Direct monitoring of ER Ca 2+ dynamics reveals that Ca 2+ entry induces ER-Ca 2+ release in astrocytes. Pflugers Arch 2020; 472:439-448. [PMID: 32246199 DOI: 10.1007/s00424-020-02364-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Revised: 01/29/2020] [Accepted: 03/12/2020] [Indexed: 12/23/2022]
Abstract
Excitability in astroglia is controlled by Ca2+ fluxes from intracellular organelles, mostly from the endoplasmic reticulum (ER). Astrocytic ER possesses inositol 1,4,5-trisphosphate receptors (InsP3R) that can be activated upon stimulation through a vast number of metabotropic G-protein-coupled receptors. By contrast, the role of Ca2+-gated Ca2+ release channels is less explored in astroglia. Here we address this process by monitoring Ca2+ dynamics directly in the cytosol and the ER of astroglial cells. Cultured astrocytes exhibited spontaneous and high-K-evoked cytosolic Ca2+ transients, both of them reversibly abolished by external Ca2+ removal, addition of plasma membrane channel blockers or ER Ca2+ depletion with SERCA inhibitors. Resting astrocyte [Ca2+]ER averaged 400 μM and maximal stimulation with ATP provoked a complete and reversible ER discharge. Direct monitoring of Ca2+ in the lumen of ER showed that high-K induced a Ca2+ release from the ER, and its amplitude was proportional to the [K]. Furthermore, by combining the low affinity GAP3 indicator targeted to the ER with the high affinity cytosolic Rhod-2, we simultaneously imaged ER- and cytosolic-Ca2+ signals, in astrocytes in culture and in situ. Plasma membrane Ca2+ entry triggered a fast ER Ca2+ release coordinated with an increase in cytosolic Ca2+. Thus, we identify a Ca2+-induced Ca2+-release (CICR) mechanism that is likely to participate in spontaneous astroglial oscillations, providing a graded amplification of the cytosolic Ca2+ signal.
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87
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Kofuji P, Araque A. G-Protein-Coupled Receptors in Astrocyte-Neuron Communication. Neuroscience 2020; 456:71-84. [PMID: 32224231 DOI: 10.1016/j.neuroscience.2020.03.025] [Citation(s) in RCA: 119] [Impact Index Per Article: 29.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Revised: 03/13/2020] [Accepted: 03/18/2020] [Indexed: 12/11/2022]
Abstract
Astrocytes, a major type of glial cell, are known to play key supportive roles in brain function, contributing to ion and neurotransmitter homeostasis, maintaining the blood-brain barrier and providing trophic and metabolic support for neurons. Besides these support functions, astrocytes are emerging as important elements in brain physiology through signaling exchange with neurons at tripartite synapses. Astrocytes express a wide variety of neurotransmitter transporters and receptors that allow them to sense and respond to synaptic activity. Principal among them are the G-protein-coupled receptors (GPCRs) in astrocytes because their activation by synaptically released neurotransmitters leads to mobilization of intracellular calcium. In turn, activated astrocytes release neuroactive substances called gliotransmitters, such as glutamate, GABA, and ATP/adenosine that lead to synaptic regulation through activation of neuronal GPCRs. In this review we will present and discuss recent evidence demonstrating the critical roles played by GPCRs in the bidirectional astrocyte-neuron signaling, and their crucial involvement in the astrocyte-mediated regulation of synaptic transmission and plasticity.
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Affiliation(s)
- 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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88
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Elangovan S, Holsinger RMD. Cyclical amyloid beta-astrocyte activity induces oxidative stress in Alzheimer's disease. Biochimie 2020; 171-172:38-42. [PMID: 32061803 DOI: 10.1016/j.biochi.2020.02.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Accepted: 02/07/2020] [Indexed: 12/14/2022]
Abstract
Glial cell involvement in Alzheimer's disease (AD) is multi-faceted. The role of astrocytes in AD pathology, both as a causative agent of amyloid-beta (Aβ) production as well as a casualty of dysfunction resulting from the presence of Aβ has been well-delineated. In this review, we explore the influence of oxidative stress in astrocytes and the subsequent effect on Aβ levels in the brain from a perspective of intracellular calcium homeostasis and NADPH oxidase activity. The response of astrocytes to the presence of Aβ, as well astrocytic and microglial interaction and inflammatory cytokine release is also discussed, highlighting a cyclical behaviour of these cells in contributing to AD pathogenesis.
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Affiliation(s)
- Shalini Elangovan
- Laboratory of Molecular Neuroscience and Dementia, Brain and Mind Centre, Faculty of Medicine and Health, The University of Sydney, Camperdown, NSW, 2050, Australia
| | - R M Damian Holsinger
- Laboratory of Molecular Neuroscience and Dementia, Brain and Mind Centre, Faculty of Medicine and Health, The University of Sydney, Camperdown, NSW, 2050, Australia; Discipline of Pathology, School of Medical Sciences, Faculty of Medicine and Health, The University of Sydney, Camperdown, NSW, 2006, Australia.
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89
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Yu X, Nagai J, Khakh BS. Improved tools to study astrocytes. Nat Rev Neurosci 2020; 21:121-138. [DOI: 10.1038/s41583-020-0264-8] [Citation(s) in RCA: 112] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/09/2020] [Indexed: 12/21/2022]
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90
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Distinct temporal integration of noradrenaline signaling by astrocytic second messengers during vigilance. Nat Commun 2020; 11:471. [PMID: 31980655 PMCID: PMC6981284 DOI: 10.1038/s41467-020-14378-x] [Citation(s) in RCA: 80] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2019] [Accepted: 12/17/2019] [Indexed: 01/12/2023] Open
Abstract
Astrocytes may function as mediators of the impact of noradrenaline on neuronal function. Activation of glial α1-adrenergic receptors triggers rapid astrocytic Ca2+ elevation and facilitates synaptic plasticity, while activation of β-adrenergic receptors elevates cAMP levels and modulates memory consolidation. However, the dynamics of these processes in behaving mice remain unexplored, as do the interactions between the distinct second messenger pathways. Here we simultaneously monitored astrocytic Ca2+ and cAMP and demonstrate that astrocytic second messengers are regulated in a temporally distinct manner. In behaving mice, we found that while an abrupt facial air puff triggered transient increases in noradrenaline release and large cytosolic astrocytic Ca2+ elevations, cAMP changes were not detectable. By contrast, repeated aversive stimuli that lead to prolonged periods of vigilance were accompanied by robust noradrenergic axonal activity and gradual sustained cAMP increases. Our findings suggest distinct astrocytic signaling pathways can integrate noradrenergic activity during vigilance states to mediate distinct functions supporting memory. Astrocytic GPCRs activate Ca2+ and cAMP signaling pathways, however, the in vivo dynamics of the two second messengers have not been fully been characterized. The authors demonstrate distinct noradrenaline-induced astrocytic Ca2+ and cAMP dynamics during startle and fear conditioning.
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91
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Lagos-Cabré R, Burgos-Bravo F, Avalos AM, Leyton L. Connexins in Astrocyte Migration. Front Pharmacol 2020; 10:1546. [PMID: 32009957 PMCID: PMC6974553 DOI: 10.3389/fphar.2019.01546] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Accepted: 11/29/2019] [Indexed: 12/18/2022] Open
Abstract
Astrocytes have long been considered the supportive cells of the central nervous system, but during the last decades, they have gained much more attention because of their active participation in the modulation of neuronal function. For example, after brain damage, astrocytes become reactive and undergo characteristic morphological and molecular changes, such as hypertrophy and increase in the expression of glial fibrillary acidic protein (GFAP), in a process known as astrogliosis. After severe damage, astrocytes migrate to the lesion site and proliferate, which leads to the formation of a glial scar. At this scar-forming stage, astrocytes secrete many factors, such as extracellular matrix proteins, cytokines, growth factors and chondroitin sulfate proteoglycans, stop migrating, and the process is irreversible. Although reactive gliosis is a normal physiological response that can protect brain cells from further damage, it also has detrimental effects on neuronal survival, by creating a hostile and non-permissive environment for axonal repair. The transformation of astrocytes from reactive to scar-forming astrocytes highlights migration as a relevant regulator of glial scar formation, and further emphasizes the importance of efficient communication between astrocytes in order to orchestrate cell migration. The coordination between astrocytes occurs mainly through Connexin (Cx) channels, in the form of direct cell-cell contact (gap junctions, GJs) or contact between the extracellular matrix and the astrocytes (hemichannels, HCs). Reactive astrocytes increase the expression levels of several proteins involved in astrocyte migration, such as αvβ3 Integrin, Syndecan-4 proteoglycan, the purinergic receptor P2X7, Pannexin1, and Cx43 HCs. Evidence has indicated that Cx43 HCs play a role in regulating astrocyte migration through the release of small molecules to the extracellular space, which then activate receptors in the same or adjacent cells to continue the signaling cascades required for astrocyte migration. In this review, we describe the communication of astrocytes through Cxs, the role of Cxs in inflammation and astrocyte migration, and discuss the molecular mechanisms that regulate Cx43 HCs, which may provide a therapeutic window of opportunity to control astrogliosis and the progression of neurodegenerative diseases.
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Affiliation(s)
- Raúl Lagos-Cabré
- Cellular Communication Laboratory, Programa de Biología Celular y Molecular, Instituto de Ciencias Biomédicas (ICBM), Facultad de Medicina, Universidad de Chile, Santiago, Chile.,Advanced Center for Chronic Diseases (ACCDiS), Center for Studies on Exercise, Metabolism and Cancer (CEMC), Facultad de Medicina, Instituto de Ciencias Biomédicas (ICBM), Universidad de Chile, Santiago, Chile
| | - Francesca Burgos-Bravo
- Cellular Communication Laboratory, Programa de Biología Celular y Molecular, Instituto de Ciencias Biomédicas (ICBM), Facultad de Medicina, Universidad de Chile, Santiago, Chile.,Advanced Center for Chronic Diseases (ACCDiS), Center for Studies on Exercise, Metabolism and Cancer (CEMC), Facultad de Medicina, Instituto de Ciencias Biomédicas (ICBM), Universidad de Chile, Santiago, Chile
| | - Ana María Avalos
- Facultad de Ciencias de la Salud, Instituto de Ciencias Biomédicas, Universidad Autónoma de Chile, Santiago, Chile
| | - Lisette Leyton
- Cellular Communication Laboratory, Programa de Biología Celular y Molecular, Instituto de Ciencias Biomédicas (ICBM), Facultad de Medicina, Universidad de Chile, Santiago, Chile.,Advanced Center for Chronic Diseases (ACCDiS), Center for Studies on Exercise, Metabolism and Cancer (CEMC), Facultad de Medicina, Instituto de Ciencias Biomédicas (ICBM), Universidad de Chile, Santiago, Chile
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92
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Classical-quantum interfaces in living neural tissue supporting conscious functions. ADVANCES IN QUANTUM CHEMISTRY 2020. [DOI: 10.1016/bs.aiq.2020.08.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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93
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Heuser K, Nome CG, Pettersen KH, Åbjørsbråten KS, Jensen V, Tang W, Sprengel R, Taubøll E, Nagelhus EA, Enger R. Ca2+ Signals in Astrocytes Facilitate Spread of Epileptiform Activity. Cereb Cortex 2019; 28:4036-4048. [PMID: 30169757 PMCID: PMC6188565 DOI: 10.1093/cercor/bhy196] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2018] [Accepted: 07/21/2018] [Indexed: 01/04/2023] Open
Abstract
Epileptic seizures are associated with increased astrocytic Ca2+ signaling, but the fine spatiotemporal kinetics of the ictal astrocyte–neuron interplay remains elusive. By using 2-photon imaging of awake head-fixed mice with chronic hippocampal windows we demonstrate that astrocytic Ca2+ signals precede neuronal Ca2+ elevations during the initial bout of kainate-induced seizures. On average, astrocytic Ca2+ elevations preceded neuronal activity in CA1 by about 8 s. In subsequent bouts of epileptic seizures, astrocytes and neurons were activated simultaneously. The initial astrocytic Ca2+ elevation was abolished in mice lacking the type 2 inositol-1,4,5-trisphosphate-receptor (Itpr2−/−). Furthermore, we found that Itpr2−/− mice exhibited 60% less epileptiform activity compared with wild-type mice when assessed by telemetric EEG monitoring. In both genotypes we also demonstrate that spreading depression waves may play a part in seizure termination. Our findings imply a role for astrocytic Ca2+ signals in ictogenesis.
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Affiliation(s)
- Kjell Heuser
- Department of Neurology, Oslo University Hospital, Rikshospitalet, Oslo, Norway
| | - Cecilie G Nome
- Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Klas H Pettersen
- Letten Centre and GliaLab, Division of Physiology, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
| | - Knut S Åbjørsbråten
- Letten Centre and GliaLab, Division of Physiology, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
| | - Vidar Jensen
- Letten Centre and GliaLab, Division of Physiology, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
| | - Wannan Tang
- Letten Centre and GliaLab, Division of Physiology, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
| | - Rolf Sprengel
- Max Planck Research Group "Molecular Neurobiology" at the Institute for Anatomy and Cell Biology, Heidelberg University, Heidelberg, Germany
| | - Erik Taubøll
- Department of Neurology, Oslo University Hospital, Rikshospitalet, Oslo, Norway.,Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Erlend A Nagelhus
- Department of Neurology, Oslo University Hospital, Rikshospitalet, Oslo, Norway.,Letten Centre and GliaLab, Division of Physiology, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
| | - Rune Enger
- Department of Neurology, Oslo University Hospital, Rikshospitalet, Oslo, Norway.,Letten Centre and GliaLab, Division of Physiology, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
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94
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Vardjan N, Parpura V, Verkhratsky A, Zorec R. Gliocrine System: Astroglia as Secretory Cells of the CNS. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1175:93-115. [PMID: 31583585 DOI: 10.1007/978-981-13-9913-8_4] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Astrocytes are secretory cells, actively participating in cell-to-cell communication in the central nervous system (CNS). They sense signaling molecules in the extracellular space, around the nearby synapses and also those released at much farther locations in the CNS, by their cell surface receptors, get excited to then release their own signaling molecules. This contributes to the brain information processing, based on diffusion within the extracellular space around the synapses and on convection when locales relatively far away from the release sites are involved. These functions resemble secretion from endocrine cells, therefore astrocytes were termed to be a part of the gliocrine system in 2015. An important mechanism, by which astrocytes release signaling molecules is the merger of the vesicle membrane with the plasmalemma, i.e., exocytosis. Signaling molecules stored in astroglial secretory vesicles can be discharged into the extracellular space after the vesicle membrane fuses with the plasma membrane. This leads to a fusion pore formation, a channel that must widen to allow the exit of the Vesiclal cargo. Upon complete vesicle membrane fusion, this process also integrates other proteins, such as receptors, transporters and channels into the plasma membrane, determining astroglial surface signaling landscape. Vesiclal cargo, together with the whole vesicle can also exit astrocytes by the fusion of multivesicular bodies with the plasma membrane (exosomes) or by budding of vesicles (ectosomes) from the plasma membrane into the extracellular space. These astroglia-derived extracellular vesicles can later interact with various target cells. Here, the characteristics of four types of astroglial secretory vesicles: synaptic-like microvesicles, dense-core vesicles, secretory lysosomes, and extracellular vesicles, are discussed. Then machinery for vesicle-based exocytosis, second messenger regulation and the kinetics of exocytotic vesicle content discharge or release of extracellular vesicles are considered. In comparison to rapidly responsive, electrically excitable neurons, the receptor-mediated cytosolic excitability-mediated astroglial exocytotic vesicle-based transmitter release is a relatively slow process.
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Affiliation(s)
- Nina Vardjan
- Laboratory of Neuroendocrinology-Molecular Cell Physiology, Faculty of Medicine, Institute of Pathophysiology, University of Ljubljana, 1000, Ljubljana, Slovenia. .,Celica Biomedical, 1000, Ljubljana, Slovenia.
| | - Vladimir Parpura
- Department of Neurobiology, The University of Alabama at Birmingham, Birmingham, AL, USA
| | - Alexei Verkhratsky
- Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, M13 9PT, UK.,Center for Basic and Translational Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, 2200, Copenhagen, Denmark.,Achucarro Center for Neuroscience, IKERBASQUE, Basque Foundation for Science, 48011, Bilbao, Spain
| | - Robert Zorec
- Laboratory of Neuroendocrinology-Molecular Cell Physiology, Faculty of Medicine, Institute of Pathophysiology, University of Ljubljana, 1000, Ljubljana, Slovenia. .,Celica Biomedical, 1000, Ljubljana, Slovenia.
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95
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Toth AB, Hori K, Novakovic MM, Bernstein NG, Lambot L, Prakriya M. CRAC channels regulate astrocyte Ca 2+ signaling and gliotransmitter release to modulate hippocampal GABAergic transmission. Sci Signal 2019; 12:12/582/eaaw5450. [PMID: 31113852 DOI: 10.1126/scisignal.aaw5450] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Astrocytes are the major glial subtype in the brain and mediate numerous functions ranging from metabolic support to gliotransmitter release through signaling mechanisms controlled by Ca2+ Despite intense interest, the Ca2+ influx pathways in astrocytes remain obscure, hindering mechanistic insights into how Ca2+ signaling is coupled to downstream astrocyte-mediated effector functions. Here, we identified store-operated Ca2+ release-activated Ca2+ (CRAC) channels encoded by Orai1 and STIM1 as a major route of Ca2+ entry for driving sustained and oscillatory Ca2+ signals in astrocytes after stimulation of metabotropic purinergic and protease-activated receptors. Using synaptopHluorin as an optical reporter, we showed that the opening of astrocyte CRAC channels stimulated vesicular exocytosis to mediate the release of gliotransmitters, including ATP. Furthermore, slice electrophysiological recordings showed that activation of astrocytes by protease-activated receptors stimulated interneurons in the CA1 hippocampus to increase inhibitory postsynaptic currents on CA1 pyramidal cells. These results reveal a central role for CRAC channels as regulators of astrocyte Ca2+ signaling, gliotransmitter release, and astrocyte-mediated tonic inhibition of CA1 pyramidal neurons.
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Affiliation(s)
- Anna B Toth
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Kotaro Hori
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Michaela M Novakovic
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Natalie G Bernstein
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Laurie Lambot
- Department of Physiology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Murali Prakriya
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA.
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96
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Héja L, Simon Á, Szabó Z, Kardos J. Feedback adaptation of synaptic excitability via Glu:Na + symport driven astrocytic GABA and Gln release. Neuropharmacology 2019; 161:107629. [PMID: 31103619 DOI: 10.1016/j.neuropharm.2019.05.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Revised: 03/30/2019] [Accepted: 05/07/2019] [Indexed: 02/08/2023]
Abstract
Glutamatergic transmission composed of the arriving of action potential at the axon terminal, fast vesicular Glu release, postsynaptic Glu receptor activation, astrocytic Glu clearance and Glu→Gln shuttle is an abundantly investigated phenomenon. Despite its essential role, however, much less is known about the consequences of the mechanistic connotations of Glu:Na+ symport. Due to the coupled Na+ transport, Glu uptake results in significantly elevated intracellular astrocytic [Na+] that markedly alters the driving force of other Na+-coupled astrocytic transporters. The resulting GABA and Gln release by reverse transport through the respective GAT-3 and SNAT3 transporters help to re-establish the physiological Na+ homeostasis without ATP dissipation and consequently leads to enhanced tonic inhibition and replenishment of axonal glutamate pool. Here, we place this emerging astrocytic adjustment of synaptic excitability into the centre of future perspectives. This article is part of the issue entitled 'Special Issue on Neurotransmitter Transporters'.
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Affiliation(s)
- László Héja
- Functional Pharmacology Research Group, Institute of Organic Chemistry, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Magyar tudósok körútja 2, 1117, Budapest, Hungary
| | - Ágnes Simon
- Functional Pharmacology Research Group, Institute of Organic Chemistry, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Magyar tudósok körútja 2, 1117, Budapest, Hungary
| | - Zsolt Szabó
- Functional Pharmacology Research Group, Institute of Organic Chemistry, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Magyar tudósok körútja 2, 1117, Budapest, Hungary
| | - Julianna Kardos
- Functional Pharmacology Research Group, Institute of Organic Chemistry, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Magyar tudósok körútja 2, 1117, Budapest, Hungary.
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97
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Holman HA, Poppi LA, Frerck M, Rabbitt RD. Spontaneous and Acetylcholine Evoked Calcium Transients in the Developing Mouse Utricle. Front Cell Neurosci 2019; 13:186. [PMID: 31133810 PMCID: PMC6514437 DOI: 10.3389/fncel.2019.00186] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Accepted: 04/12/2019] [Indexed: 11/13/2022] Open
Abstract
Spontaneous calcium transients are present during early postnatal development in the mouse retina and cochlea, and play an important role in maturation of the sensory organs and neural circuits in the central nervous system (CNS). It is not known whether similar calcium transients occur during postnatal development in the vestibular sensory organs. Here we demonstrate spontaneous intracellular calcium transients in sensory hair cells (HCs) and supporting cells (SCs) in the murine utricular macula during the first two postnatal weeks. Calcium transients were monitored using a genetically encoded calcium indicator, GCaMP5G (G5), at 100 ms-frame−1 in excised utricle sensory epithelia, including HCs, SCs, and neurons. The reporter line expressed G5 and tdTomato (tdT) in a Gad2-Cre dependent manner within a subset of utricular HCs, SCs and neurons. Kinetics of the G5 reporter limited temporal resolution to calcium events lasting longer than 200 ms. Spontaneous calcium transients lasting 1-2 s were observed in the expressing population of HCs at birth and slower spontaneous transients lasting 10-30 s appeared in SCs by P3. Beginning at P5, calcium transients could be modulated by application of the efferent neurotransmitter acetylcholine (ACh). In mature mice, calcium transients in the utricular macula occurred spontaneously, had a duration 1-2 s, and could be modulated by the exogenous application of acetylcholine (ACh) or muscarine. Long-lasting calcium transients evoked by ACh in mature mice were blocked by atropine, consistent with previous reports describing the role of muscarinic receptors expressed in calyx bearing afferents in efferent control of vestibular sensation. Large spontaneous and ACh evoked transients were reversibly blocked by the inositol trisphosphate receptor (IP3R) antagonist aminoethoxydiphenyl borate (2-APB). Results demonstrate long-lasting calcium transients are present in the utricular macula during the first postnatal week, and that responses to ACh mature over this same time period.
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Affiliation(s)
- Holly A Holman
- Department of Biomedical Engineering, University of Utah, Salt Lake City, UT, United States
| | - Lauren A Poppi
- Department of Biomedical Engineering, University of Utah, Salt Lake City, UT, United States.,School of Biomedical Science and Pharmacy, Hunter Medical Research Institute, University of Newcastle, Newcastle, NSW, Australia
| | - Micah Frerck
- Department of Biomedical Engineering, University of Utah, Salt Lake City, UT, United States
| | - Richard D Rabbitt
- Department of Biomedical Engineering, University of Utah, Salt Lake City, UT, United States.,Neuroscience Program, University of Utah, Salt Lake City, UT, United States.,Otolaryngology-Head and Neck Surgery, University of Utah, Salt Lake City, UT, United States
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98
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Weiss S, Melom JE, Ormerod KG, Zhang YV, Littleton JT. Glial Ca 2+signaling links endocytosis to K + buffering around neuronal somas to regulate excitability. eLife 2019; 8:44186. [PMID: 31025939 PMCID: PMC6510531 DOI: 10.7554/elife.44186] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Accepted: 04/25/2019] [Indexed: 12/30/2022] Open
Abstract
Glial-neuronal signaling at synapses is widely studied, but how glia interact with neuronal somas to regulate their activity is unclear. Drosophila cortex glia are restricted to brain regions devoid of synapses, providing an opportunity to characterize interactions with neuronal somas. Mutations in the cortex glial NCKXzydeco elevate basal Ca2+, predisposing animals to seizure-like behavior. To determine how cortex glial Ca2+ signaling controls neuronal excitability, we performed an in vivo modifier screen of the NCKXzydeco seizure phenotype. We show that elevation of glial Ca2+ causes hyperactivation of calcineurin-dependent endocytosis and accumulation of early endosomes. Knockdown of sandman, a K2P channel, recapitulates NCKXzydeco seizures. Indeed, sandman expression on cortex glial membranes is substantially reduced in NCKXzydeco mutants, indicating enhanced internalization of sandman predisposes animals to seizures. These data provide an unexpected link between glial Ca2+ signaling and the well-known role of glia in K+ buffering as a key mechanism for regulating neuronal excitability.
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Affiliation(s)
- Shirley Weiss
- The Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, United States.,Department of Biology, Massachusetts Institute of Technology, Cambridge, United States.,Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, United States
| | - Jan E Melom
- The Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, United States.,Department of Biology, Massachusetts Institute of Technology, Cambridge, United States.,Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, United States
| | - Kiel G Ormerod
- The Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, United States.,Department of Biology, Massachusetts Institute of Technology, Cambridge, United States.,Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, United States
| | - Yao V Zhang
- The Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, United States.,Department of Biology, Massachusetts Institute of Technology, Cambridge, United States.,Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, United States
| | - J Troy Littleton
- Department of Biology, Massachusetts Institute of Technology, Cambridge, United States
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99
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Bramini M, Chiacchiaretta M, Armirotti A, Rocchi A, Kale DD, Martin C, Vázquez E, Bandiera T, Ferroni S, Cesca F, Benfenati F. An Increase in Membrane Cholesterol by Graphene Oxide Disrupts Calcium Homeostasis in Primary Astrocytes. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2019; 15:e1900147. [PMID: 30891923 DOI: 10.1002/smll.201900147] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Revised: 02/18/2019] [Indexed: 05/24/2023]
Abstract
The use of graphene nanomaterials (GNMs) for biomedical applications targeted to the central nervous system is exponentially increasing, although precise information on their effects on brain cells is lacking. In this work, the molecular changes induced in cortical astrocytes by few-layer graphene (FLG) and graphene oxide (GO) flakes are addressed. The results show that exposure to FLG/GO does not affect cell viability or proliferation. However, proteomic and lipidomic analyses unveil alterations in several cellular processes, including intracellular Ca2+ ([Ca2+ ]i ) homeostasis and cholesterol metabolism, which are particularly intense in cells exposed to GO. Indeed, GO exposure impairs spontaneous and evoked astrocyte [Ca2+ ]i signals and induces a marked increase in membrane cholesterol levels. Importantly, cholesterol depletion fully rescues [Ca2+ ]i dynamics in GO-treated cells, indicating a causal relationship between these GO-mediated effects. The results indicate that exposure to GNMs alters intracellular signaling in astrocytes and may impact astrocyte-neuron interactions.
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Affiliation(s)
- Mattia Bramini
- Center for Synaptic Neuroscience and Technology and Graphene Labs, Istituto Italiano di Tecnologia, 16132, Genova, Italy
- IRCCS Ospedale Policlinico San Martino, 16132, Genova, Italy
| | - Martina Chiacchiaretta
- Center for Synaptic Neuroscience and Technology and Graphene Labs, Istituto Italiano di Tecnologia, 16132, Genova, Italy
| | - Andrea Armirotti
- Analytical Chemistry Lab and Graphene Labs, Istituto Italiano di Tecnologia, 16163, Genova, Italy
| | - Anna Rocchi
- Center for Synaptic Neuroscience and Technology and Graphene Labs, Istituto Italiano di Tecnologia, 16132, Genova, Italy
- IRCCS Ospedale Policlinico San Martino, 16132, Genova, Italy
| | - Deepali D Kale
- PharmaChemistry Line and Graphene Labs, Istituto Italiano di Tecnologia, 16163, Genova, Italy
| | - Cristina Martin
- Departamento de Química Orgánica, Instituto Regional de Investigación Científica Aplicada (IRICA), Universidad de Castilla La-Mancha, 13071, Ciudad Real, Spain
| | - Ester Vázquez
- Departamento de Química Orgánica, Instituto Regional de Investigación Científica Aplicada (IRICA), Universidad de Castilla La-Mancha, 13071, Ciudad Real, Spain
| | - Tiziano Bandiera
- PharmaChemistry Line and Graphene Labs, Istituto Italiano di Tecnologia, 16163, Genova, Italy
| | - Stefano Ferroni
- Department of Pharmacy and Biotechnology, University of Bologna, 40126, Bologna, Italy
| | - Fabrizia Cesca
- Center for Synaptic Neuroscience and Technology and Graphene Labs, Istituto Italiano di Tecnologia, 16132, Genova, Italy
- Department of Life Sciences, University of Trieste, 34127, Trieste, Italy
| | - Fabio Benfenati
- Center for Synaptic Neuroscience and Technology and Graphene Labs, Istituto Italiano di Tecnologia, 16132, Genova, Italy
- IRCCS Ospedale Policlinico San Martino, 16132, Genova, Italy
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100
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Abstract
Background: Previous papers have developed a statistical mechanics of neocortical interactions (SMNI) fit to short-term memory and EEG data. Adaptive Simulated Annealing (ASA) has been developed to perform fits to such nonlinear stochastic systems. An N-dimensional path-integral algorithm for quantum systems, qPATHINT, has been developed from classical PATHINT. Both fold short-time propagators (distributions or wave functions) over long times. Previous papers applied qPATHINT to two systems, in neocortical interactions and financial options. Objective: In this paper the quantum path-integral for Calcium ions is used to derive a closed-form analytic solution at arbitrary time that is used to calculate interactions with classical-physics SMNI interactions among scales. Using fits of this SMNI model to EEG data, including these effects, will help determine if this is a reasonable approach. Method: Methods of mathematical-physics for optimization and for path integrals in classical and quantum spaces are used for this project. Studies using supercomputer resources tested various dimensions for their scaling limits. In this paper the quantum path-integral is used to derive a closed-form analytic solution at arbitrary time that is used to calculate interactions with classical-physics SMNI interactions among scales. Results: The mathematical-physics and computer parts of the study are successful, in that there is modest improvement of cost/objective functions used to fit EEG data using these models. Conclusions: This project points to directions for more detailed calculations using more EEG data and qPATHINT at each time slice to propagate quantum calcium waves, synchronized with PATHINT propagation of classical SMNI.
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