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Wang HY, Takagi H, Stoney PN, Echeverria A, Kuhn B, Hsu KS, Takahashi T. Anoxia-induced hippocampal LTP is regeneratively produced by glutamate and nitric oxide from the neuro-glial-endothelial axis. iScience 2024; 27:109515. [PMID: 38591010 PMCID: PMC11000013 DOI: 10.1016/j.isci.2024.109515] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Revised: 01/17/2024] [Accepted: 03/14/2024] [Indexed: 04/10/2024] Open
Abstract
Transient anoxia causes amnesia and neuronal death. This is attributed to enhanced glutamate release and modeled as anoxia-induced long-term potentiation (aLTP). aLTP is mediated by glutamate receptors and nitric oxide (·NO) and occludes stimulation-induced LTP. We identified a signaling cascade downstream of ·NO leading to glutamate release and a glutamate-·NO loop regeneratively boosting aLTP. aLTP in entothelial ·NO synthase (eNOS)-knockout mice and blocking neuronal NOS (nNOS) activity suggested that both nNOS and eNOS contribute to aLTP. Immunostaining result showed that eNOS is predominantly expressed in vascular endothelia. Transient anoxia induced a long-lasting Ca2+ elevation in astrocytes that mirrored aLTP. Blocking astrocyte metabolism or depletion of the NMDA receptor ligand D-serine abolished eNOS-dependent aLTP, suggesting that astrocytic Ca2+ elevation stimulates D-serine release from endfeet to endothelia, thereby releasing ·NO synthesized by eNOS. Thus, the neuro-glial-endothelial axis is involved in long-term enhancement of glutamate release after transient anoxia.
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Affiliation(s)
- Han-Ying Wang
- Cellular and Molecular Synaptic Function Unit, Okinawa Institute of Science and Technology Graduate University, Okinawa 904-0495, Japan
- Academia Sinica, Institute of Biomedical Sciences, Taipei 115, Taiwan
| | - Hiroshi Takagi
- Cellular and Molecular Synaptic Function Unit, Okinawa Institute of Science and Technology Graduate University, Okinawa 904-0495, Japan
- Department of Neurosurgery, Graduate School of Medicine, University of the Ryukyus, Okinawa 903-0215, Japan
| | - Patrick N. Stoney
- Cellular and Molecular Synaptic Function Unit, Okinawa Institute of Science and Technology Graduate University, Okinawa 904-0495, Japan
| | - Anai Echeverria
- Optical Neuroimaging Unit, Okinawa Institute of Science and Technology Graduate University, Okinawa 904-0495, Japan
| | - Bernd Kuhn
- Optical Neuroimaging Unit, Okinawa Institute of Science and Technology Graduate University, Okinawa 904-0495, Japan
| | - Kuei-Sen Hsu
- Department of Pharmacology, College of Medicine, National Cheng Kung University, Tainan 70101, Taiwan
| | - Tomoyuki Takahashi
- Cellular and Molecular Synaptic Function Unit, Okinawa Institute of Science and Technology Graduate University, Okinawa 904-0495, Japan
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2
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Novakovic MM, Korshunov KS, Grant RA, Martin ME, Valencia HA, Budinger GRS, Radulovic J, Prakriya M. Astrocyte reactivity and inflammation-induced depression-like behaviors are regulated by Orai1 calcium channels. Nat Commun 2023; 14:5500. [PMID: 37679321 PMCID: PMC10485021 DOI: 10.1038/s41467-023-40968-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Accepted: 08/17/2023] [Indexed: 09/09/2023] Open
Abstract
Astrocytes contribute to brain inflammation in neurological disorders but the molecular mechanisms controlling astrocyte reactivity and their relationship to neuroinflammatory endpoints are complex and poorly understood. In this study, we assessed the role of the calcium channel, Orai1, for astrocyte reactivity and inflammation-evoked depression behaviors in mice. Transcriptomics and metabolomics analysis indicated that deletion of Orai1 in astrocytes downregulates genes in inflammation and immunity, metabolism, and cell cycle pathways, and reduces cellular metabolites and ATP production. Systemic inflammation by peripheral lipopolysaccharide (LPS) increases hippocampal inflammatory markers in WT but not in astrocyte Orai1 knockout mice. Loss of Orai1 also blunts inflammation-induced astrocyte Ca2+ signaling and inhibitory neurotransmission in the hippocampus. In line with these cellular changes, Orai1 knockout mice showed amelioration of LPS-evoked depression-like behaviors including anhedonia and helplessness. These findings identify Orai1 as an important signaling hub controlling astrocyte reactivity and astrocyte-mediated brain inflammation that is commonly observed in many neurological disorders.
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Affiliation(s)
- Michaela M Novakovic
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL, 60611, USA
| | - Kirill S Korshunov
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL, 60611, USA
| | - Rogan A Grant
- Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL, 60611, USA
| | - Megan E Martin
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL, 60611, USA
| | - Hiam A Valencia
- Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL, 60611, USA
| | - G R Scott Budinger
- Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL, 60611, USA
| | - Jelena Radulovic
- Department of Neuroscience, Albert Einstein School of Medicine, Bronx, NY, 10461, USA
| | - Murali Prakriya
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL, 60611, USA.
- Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL, 60611, USA.
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3
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Patani R, Hardingham GE, Liddelow SA. Functional roles of reactive astrocytes in neuroinflammation and neurodegeneration. Nat Rev Neurol 2023; 19:395-409. [PMID: 37308616 DOI: 10.1038/s41582-023-00822-1] [Citation(s) in RCA: 83] [Impact Index Per Article: 83.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/11/2023] [Indexed: 06/14/2023]
Abstract
Despite advances in uncovering the mechanisms that underlie neuroinflammation and neurodegenerative disease, therapies that prevent neuronal loss remain elusive. Targeting of disease-defining markers in conditions such as Alzheimer disease (amyloid-β and tau) or Parkinson disease (α-synuclein) has been met with limited success, suggesting that these proteins do not act in isolation but form part of a pathological network. This network could involve phenotypic alteration of multiple cell types in the CNS, including astrocytes, which have a major neurosupportive, homeostatic role in the healthy CNS but adopt reactive states under acute or chronic adverse conditions. Transcriptomic studies in human patients and disease models have revealed the co-existence of many putative reactive sub-states of astrocytes. Inter-disease and even intra-disease heterogeneity of reactive astrocytic sub-states are well established, but the extent to which specific sub-states are shared across different diseases is unclear. In this Review, we highlight how single-cell and single-nuclei RNA sequencing and other 'omics' technologies can enable the functional characterization of defined reactive astrocyte states in various pathological scenarios. We provide an integrated perspective, advocating cross-modal validation of key findings to define functionally important sub-states of astrocytes and their triggers as tractable therapeutic targets with cross-disease relevance.
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Affiliation(s)
- Rickie Patani
- Department of Neuromuscular Disease, UCL Queen Square Institute of Neurology, London, UK
- The Francis Crick Institute, Human Stem Cells and Neurodegeneration Laboratory, London, UK
| | - Giles E Hardingham
- Euan MacDonald Centre for MND, University of Edinburgh, Edinburgh, UK
- UK Dementia Research Institute at the University of Edinburgh, University of Edinburgh, Edinburgh, UK
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK
| | - Shane A Liddelow
- Neuroscience Institute, NYU Grossman School of Medicine, New York, NY, USA.
- Department of Neuroscience & Physiology, NYU Grossman School of Medicine, New York, NY, USA.
- Department of Ophthalmology, NYU Grossman School of Medicine, New York, NY, USA.
- Parekh Center for Interdisciplinary Neurology, NYU Grossman School of Medicine, New York, NY, USA.
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4
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Cunha-Garcia D, Monteiro-Fernandes D, Correia JS, Neves-Carvalho A, Vilaça-Ferreira AC, Guerra-Gomes S, Viana JF, Oliveira JF, Teixeira-Castro A, Maciel P, Duarte-Silva S. Genetic Ablation of Inositol 1,4,5-Trisphosphate Receptor Type 2 (IP 3R2) Fails to Modify Disease Progression in a Mouse Model of Spinocerebellar Ataxia Type 3. Int J Mol Sci 2023; 24:10606. [PMID: 37445783 PMCID: PMC10341520 DOI: 10.3390/ijms241310606] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Revised: 06/07/2023] [Accepted: 06/16/2023] [Indexed: 07/15/2023] Open
Abstract
Spinocerebellar ataxia type 3 (SCA3) is a rare neurodegenerative disease caused by an abnormal polyglutamine expansion within the ataxin-3 protein (ATXN3). This leads to neurodegeneration of specific brain and spinal cord regions, resulting in a progressive loss of motor function. Despite neuronal death, non-neuronal cells, including astrocytes, are also involved in SCA3 pathogenesis. Astrogliosis is a common pathological feature in SCA3 patients and animal models of the disease. However, the contribution of astrocytes to SCA3 is not clearly defined. Inositol 1,4,5-trisphosphate receptor type 2 (IP3R2) is the predominant IP3R in mediating astrocyte somatic calcium signals, and genetically ablation of IP3R2 has been widely used to study astrocyte function. Here, we aimed to investigate the relevance of IP3R2 in the onset and progression of SCA3. For this, we tested whether IP3R2 depletion and the consecutive suppression of global astrocytic calcium signalling would lead to marked changes in the behavioral phenotype of a SCA3 mouse model, the CMVMJD135 transgenic line. This was achieved by crossing IP3R2 null mice with the CMVMJD135 mouse model and performing a longitudinal behavioral characterization of these mice using well-established motor-related function tests. Our results demonstrate that IP3R2 deletion in astrocytes does not modify SCA3 progression.
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Affiliation(s)
- Daniela Cunha-Garcia
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, 4710-057 Braga, Portugal; (D.C.-G.); (D.M.-F.); (J.S.C.); (A.N.-C.); (A.C.V.-F.); (S.G.-G.); (J.F.V.); (J.F.O.); (A.T.-C.)
- ICVS/3B’s—PT Government Associate Laboratory, 4710-057 Braga/4805-017 Guimarães, Portugal
| | - Daniela Monteiro-Fernandes
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, 4710-057 Braga, Portugal; (D.C.-G.); (D.M.-F.); (J.S.C.); (A.N.-C.); (A.C.V.-F.); (S.G.-G.); (J.F.V.); (J.F.O.); (A.T.-C.)
- ICVS/3B’s—PT Government Associate Laboratory, 4710-057 Braga/4805-017 Guimarães, Portugal
| | - Joana Sofia Correia
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, 4710-057 Braga, Portugal; (D.C.-G.); (D.M.-F.); (J.S.C.); (A.N.-C.); (A.C.V.-F.); (S.G.-G.); (J.F.V.); (J.F.O.); (A.T.-C.)
- ICVS/3B’s—PT Government Associate Laboratory, 4710-057 Braga/4805-017 Guimarães, Portugal
| | - Andreia Neves-Carvalho
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, 4710-057 Braga, Portugal; (D.C.-G.); (D.M.-F.); (J.S.C.); (A.N.-C.); (A.C.V.-F.); (S.G.-G.); (J.F.V.); (J.F.O.); (A.T.-C.)
- ICVS/3B’s—PT Government Associate Laboratory, 4710-057 Braga/4805-017 Guimarães, Portugal
| | - Ana Catarina Vilaça-Ferreira
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, 4710-057 Braga, Portugal; (D.C.-G.); (D.M.-F.); (J.S.C.); (A.N.-C.); (A.C.V.-F.); (S.G.-G.); (J.F.V.); (J.F.O.); (A.T.-C.)
- ICVS/3B’s—PT Government Associate Laboratory, 4710-057 Braga/4805-017 Guimarães, Portugal
| | - Sónia Guerra-Gomes
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, 4710-057 Braga, Portugal; (D.C.-G.); (D.M.-F.); (J.S.C.); (A.N.-C.); (A.C.V.-F.); (S.G.-G.); (J.F.V.); (J.F.O.); (A.T.-C.)
- ICVS/3B’s—PT Government Associate Laboratory, 4710-057 Braga/4805-017 Guimarães, Portugal
| | - João Filipe Viana
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, 4710-057 Braga, Portugal; (D.C.-G.); (D.M.-F.); (J.S.C.); (A.N.-C.); (A.C.V.-F.); (S.G.-G.); (J.F.V.); (J.F.O.); (A.T.-C.)
- ICVS/3B’s—PT Government Associate Laboratory, 4710-057 Braga/4805-017 Guimarães, Portugal
| | - João Filipe Oliveira
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, 4710-057 Braga, Portugal; (D.C.-G.); (D.M.-F.); (J.S.C.); (A.N.-C.); (A.C.V.-F.); (S.G.-G.); (J.F.V.); (J.F.O.); (A.T.-C.)
- ICVS/3B’s—PT Government Associate Laboratory, 4710-057 Braga/4805-017 Guimarães, Portugal
- IPCA-EST-2Ai, Polytechnic Institute of Cávado and Ave, Applied Artificial Intelligence Laboratory, Campus of IPCA, 4750-810 Barcelos, Portugal
| | - Andreia Teixeira-Castro
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, 4710-057 Braga, Portugal; (D.C.-G.); (D.M.-F.); (J.S.C.); (A.N.-C.); (A.C.V.-F.); (S.G.-G.); (J.F.V.); (J.F.O.); (A.T.-C.)
- ICVS/3B’s—PT Government Associate Laboratory, 4710-057 Braga/4805-017 Guimarães, Portugal
| | - Patrícia Maciel
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, 4710-057 Braga, Portugal; (D.C.-G.); (D.M.-F.); (J.S.C.); (A.N.-C.); (A.C.V.-F.); (S.G.-G.); (J.F.V.); (J.F.O.); (A.T.-C.)
- ICVS/3B’s—PT Government Associate Laboratory, 4710-057 Braga/4805-017 Guimarães, Portugal
| | - Sara Duarte-Silva
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, 4710-057 Braga, Portugal; (D.C.-G.); (D.M.-F.); (J.S.C.); (A.N.-C.); (A.C.V.-F.); (S.G.-G.); (J.F.V.); (J.F.O.); (A.T.-C.)
- ICVS/3B’s—PT Government Associate Laboratory, 4710-057 Braga/4805-017 Guimarães, Portugal
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5
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Xiong H, Tang F, Guo Y, Xu R, Lei P. Neural Circuit Changes in Neurological Disorders: Evidence from in vivo Two-photon Imaging. Ageing Res Rev 2023; 87:101933. [PMID: 37061201 DOI: 10.1016/j.arr.2023.101933] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Accepted: 04/11/2023] [Indexed: 04/17/2023]
Abstract
Neural circuits, such as synaptic plasticity and neural activity, are critical components of healthy brain function. The consequent dynamic remodeling of neural circuits is an ongoing procedure affecting neuronal activities. Disruption of this essential process results in diseases. Advanced microscopic applications such as two-photon laser scanning microscopy have recently been applied to understand neural circuit changes during disease since it can visualize fine structural and functional cellular activation in living animals. In this review, we have summarized the latest work assessing the dynamic rewiring of postsynaptic dendritic spines and modulation of calcium transients in neurons of the intact living brain, focusing on their potential roles in neurological disorders (e.g. Alzheimer's disease, stroke, and epilepsy). Understanding the fine changes that occurred in the brain during disease is crucial for future clinical intervention developments.
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Affiliation(s)
- Huan Xiong
- Department of Neurosurgery, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, 610072, China; Chinese Academy of Sciences Sichuan Translational Medicine Research Hospital, Chengdu, 610072, China; Department of Neurology and State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Sichuan, Chengdu, 610041, China
| | - Fei Tang
- Department of Neurology and State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Sichuan, Chengdu, 610041, China
| | - Yujie Guo
- Department of Neurology and State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Sichuan, Chengdu, 610041, China
| | - Ruxiang Xu
- Department of Neurosurgery, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, 610072, China; Chinese Academy of Sciences Sichuan Translational Medicine Research Hospital, Chengdu, 610072, China
| | - Peng Lei
- Department of Neurology and State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Sichuan, Chengdu, 610041, China.
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6
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Liang Z, Lou Y, Hao Y, Li H, Feng J, Liu S. The Relationship of Astrocytes and Microglia with Different Stages of Ischemic Stroke. Curr Neuropharmacol 2023; 21:2465-2480. [PMID: 37464832 PMCID: PMC10616922 DOI: 10.2174/1570159x21666230718104634] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2022] [Revised: 01/31/2023] [Accepted: 02/04/2023] [Indexed: 07/20/2023] Open
Abstract
Ischemic stroke is the predominant cause of severe morbidity and mortality worldwide. Post-stroke neuroinflammation has recently received increasing attention with the aim of providing a new effective treatment strategy for ischemic stroke. Microglia and astrocytes are major components of the innate immune system of the central nervous system. They can be involved in all phases of ischemic stroke, from the early stage, contributing to the first wave of neuronal cell death, to the late stage involving phagocytosis and repair. In the early stage of ischemic stroke, a vicious cycle exists between the activation of microglia and astrocytes (through astrocytic connexin 43 hemichannels), aggravating neuroinflammatory injury post-stroke. However, in the late stage of ischemic stroke, repeatedly activated microglia can induce the formation of glial scars by triggering reactive astrogliosis in the peri-infarct regions, which may limit the movement of activated microglia in reverse and restrict the diffusion of inflammation to healthy brain tissues, alleviating the neuroinflammatory injury poststroke. In this review, we elucidated the various roles of astrocytes and microglia and summarized their relationship with neuroinflammation. We also examined how astrocytes and microglia influence each other at different stages of ischemic stroke. Several potential therapeutic approaches targeting astrocytes and microglia in ischemic stroke have been reviewed. Understanding the details of astrocytemicroglia interaction processes will contribute to a better understanding of the mechanisms underlying ischemic stroke, contributing to the identification of new therapeutic interventions.
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Affiliation(s)
- Zhen Liang
- Department of Neurology, China-Japan Union Hospital, Jilin University, Changchun, China
| | - Yingyue Lou
- Department of Rehabilitation, The Second Hospital of Jilin University, Changchun, China
| | - Yulei Hao
- Department of Neurology and Neuroscience Center, The First Hospital of Jilin University, Changchun, China
| | - Hui Li
- Department of Neurology and Neuroscience Center, The First Hospital of Jilin University, Changchun, China
| | - Jiachun Feng
- Department of Neurology and Neuroscience Center, The First Hospital of Jilin University, Changchun, China
| | - Songyan Liu
- Department of Neurology, China-Japan Union Hospital, Jilin University, Changchun, China
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7
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Excitatory Synaptic Transmission in Ischemic Stroke: A New Outlet for Classical Neuroprotective Strategies. Int J Mol Sci 2022; 23:ijms23169381. [PMID: 36012647 PMCID: PMC9409263 DOI: 10.3390/ijms23169381] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Revised: 08/15/2022] [Accepted: 08/17/2022] [Indexed: 01/01/2023] Open
Abstract
Stroke is one of the leading causes of death and disability in the world, of which ischemia accounts for the majority. There is growing evidence of changes in synaptic connections and neural network functions in the brain of stroke patients. Currently, the studies on these neurobiological alterations mainly focus on the principle of glutamate excitotoxicity, and the corresponding neuroprotective strategies are limited to blocking the overactivation of ionic glutamate receptors. Nevertheless, it is disappointing that these treatments often fail because of the unspecificity and serious side effects of the tested drugs in clinical trials. Thus, in the prevention and treatment of stroke, finding and developing new targets of neuroprotective intervention is still the focus and goal of research in this field. In this review, we focus on the whole processes of glutamatergic synaptic transmission and highlight the pathological changes underlying each link to help develop potential therapeutic strategies for ischemic brain damage. These strategies include: (1) controlling the synaptic or extra-synaptic release of glutamate, (2) selectively blocking the action of the glutamate receptor NMDAR subunit, (3) increasing glutamate metabolism, and reuptake in the brain and blood, and (4) regulating the glutamate system by GABA receptors and the microbiota–gut–brain axis. Based on these latest findings, it is expected to promote a substantial understanding of the complex glutamate signal transduction mechanism, thereby providing excellent neuroprotection research direction for human ischemic stroke (IS).
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8
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Schroeder ME, Bassett DS, Meaney DF. A multilayer network model of neuron-astrocyte populations in vitro reveals mGluR5 inhibition is protective following traumatic injury. Netw Neurosci 2022; 6:499-527. [PMID: 35733423 PMCID: PMC9208011 DOI: 10.1162/netn_a_00227] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Accepted: 01/04/2022] [Indexed: 11/16/2022] Open
Abstract
Astrocytes communicate bidirectionally with neurons, enhancing synaptic plasticity and promoting the synchronization of neuronal microcircuits. Despite recent advances in understanding neuron-astrocyte signaling, little is known about astrocytic modulation of neuronal activity at the population level, particularly in disease or following injury. We used high-speed calcium imaging of mixed cortical cultures in vitro to determine how population activity changes after disruption of glutamatergic signaling and mechanical injury. We constructed a multilayer network model of neuron-astrocyte connectivity, which captured distinct topology and response behavior from single-cell-type networks. mGluR5 inhibition decreased neuronal activity, but did not on its own disrupt functional connectivity or network topology. In contrast, injury increased the strength, clustering, and efficiency of neuronal but not astrocytic networks, an effect that was not observed in networks pretreated with mGluR5 inhibition. Comparison of spatial and functional connectivity revealed that functional connectivity is largely independent of spatial proximity at the microscale, but mechanical injury increased the spatial-functional correlation. Finally, we found that astrocyte segments of the same cell often belong to separate functional communities based on neuronal connectivity, suggesting that astrocyte segments function as independent entities. Our findings demonstrate the utility of multilayer network models for characterizing the multiscale connectivity of two distinct but functionally dependent cell populations. Astrocytes communicate bidirectionally with neurons, enhancing synaptic plasticity and promoting the synchronization of neuronal microcircuits. We constructed a multilayer network model of neuron-astrocyte connectivity based on calcium activity in mixed cortical cultures, and used this model to evaluate the effect of glutamatergic inhibition and mechanical injury on network topology. We found that injury increased the strength, clustering, and efficiency of neuronal but not astrocytic networks, an effect that was not observed in injured networks pretreated with a glutamate receptor antagonist. Our findings demonstrate the utility of multilayer network models for characterizing the multiscale connectivity of two distinct but functionally dependent cell populations.
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Affiliation(s)
- Margaret E. Schroeder
- Department of Bioengineering, School of Engineering & Applied Science, University of Pennsylvania, Philadelphia, PA, USA
| | - Danielle S. Bassett
- Department of Bioengineering, School of Engineering & Applied Science, University of Pennsylvania, Philadelphia, PA, USA
- Department of Physics & Astronomy, College of Arts & Sciences, University of Pennsylvania, Philadelphia, PA, USA
- Department of Electrical & Systems Engineering, School of Engineering & Applied Science, University of Pennsylvania, Philadelphia, PA, USA
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - David F. Meaney
- Department of Bioengineering, School of Engineering & Applied Science, University of Pennsylvania, Philadelphia, PA, USA
- Department of Neurosurgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
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9
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Singer T, Ding S, Ding S. Astroglia Abnormalities in Post-stroke Mood Disorders. ADVANCES IN NEUROBIOLOGY 2021; 26:115-138. [PMID: 34888833 DOI: 10.1007/978-3-030-77375-5_6] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Stroke is the leading cause of human death and disability. After a stroke, many patients may have some physical disability, including difficulties in moving, speaking, and seeing, but patients may also exhibit changes in mood manifested by depression, anxiety, and cognitive changes which we call post-stroke mood disorders (PSMDs). Astrocytes are the most diverse and numerous glial cell type in the central nervous system (CNS). They provide structural, nutritional, and metabolic support to neurons and regulate synaptic activity under normal conditions. Astrocytes are also critically involved in focal ischemic stroke (FIS). They undergo many changes after FIS. These changes may affect acute neuronal death and brain damage as well as brain recovery and PSMD in the chronic phase after FIS. Studies using postmortem brain specimens and animal models of FIS suggest that astrocytes/reactive astrocytes are involved in PSMD. This chapter provides an overview of recent advances in the molecular base of astrocyte in PSMD. As astrocytes exhibit high plasticity after FIS, we suggest that targeting local astrocytes may be a promising strategy for PSMD therapy.
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Affiliation(s)
- Tracey Singer
- Dalton Cardiovascular Research Center, Columbia, MO, USA
| | - Sarah Ding
- Dalton Cardiovascular Research Center, Columbia, MO, USA
| | - Shinghua Ding
- Dalton Cardiovascular Research Center, Columbia, MO, USA.
- Department of Biomedical, Biological and Chemical Engineering, University of Missouri, Columbia, MO, USA.
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10
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Alia C, Cangi D, Massa V, Salluzzo M, Vignozzi L, Caleo M, Spalletti C. Cell-to-Cell Interactions Mediating Functional Recovery after Stroke. Cells 2021; 10:3050. [PMID: 34831273 PMCID: PMC8623942 DOI: 10.3390/cells10113050] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Revised: 10/27/2021] [Accepted: 11/02/2021] [Indexed: 12/22/2022] Open
Abstract
Ischemic damage in brain tissue triggers a cascade of molecular and structural plastic changes, thus influencing a wide range of cell-to-cell interactions. Understanding and manipulating this scenario of intercellular connections is the Holy Grail for post-stroke neurorehabilitation. Here, we discuss the main findings in the literature related to post-stroke alterations in cell-to-cell interactions, which may be either detrimental or supportive for functional recovery. We consider both neural and non-neural cells, starting from astrocytes and reactive astrogliosis and moving to the roles of the oligodendrocytes in the support of vulnerable neurons and sprouting inhibition. We discuss the controversial role of microglia in neural inflammation after injury and we conclude with the description of post-stroke alterations in pyramidal and GABAergic cells interactions. For all of these sections, we review not only the spontaneous evolution in cellular interactions after ischemic injury, but also the experimental strategies which have targeted these interactions and that are inspiring novel therapeutic strategies for clinical application.
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Affiliation(s)
- Claudia Alia
- Neuroscience Institute, National Research Council (CNR), Via G. Moruzzi 1, 56124 Pisa, Italy; (V.M.); (M.S.); (M.C.); (C.S.)
| | - Daniele Cangi
- Department of Neurosciences, Psychology, Drugs and Child Health Area, School of Psychology, University of Florence, 50121 Florence, Italy;
| | - Verediana Massa
- Neuroscience Institute, National Research Council (CNR), Via G. Moruzzi 1, 56124 Pisa, Italy; (V.M.); (M.S.); (M.C.); (C.S.)
| | - Marco Salluzzo
- Neuroscience Institute, National Research Council (CNR), Via G. Moruzzi 1, 56124 Pisa, Italy; (V.M.); (M.S.); (M.C.); (C.S.)
- Department of Neurosciences, Psychology, Drugs and Child Health Area, School of Psychology, University of Florence, 50121 Florence, Italy;
| | - Livia Vignozzi
- Department of Biomedical Sciences, University of Padua, Viale G. Colombo 3, 35121 Padua, Italy;
| | - Matteo Caleo
- Neuroscience Institute, National Research Council (CNR), Via G. Moruzzi 1, 56124 Pisa, Italy; (V.M.); (M.S.); (M.C.); (C.S.)
- Department of Biomedical Sciences, University of Padua, Viale G. Colombo 3, 35121 Padua, Italy;
| | - Cristina Spalletti
- Neuroscience Institute, National Research Council (CNR), Via G. Moruzzi 1, 56124 Pisa, Italy; (V.M.); (M.S.); (M.C.); (C.S.)
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11
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Adrenergic inhibition facilitates normalization of extracellular potassium after cortical spreading depolarization. Sci Rep 2021; 11:8150. [PMID: 33854148 PMCID: PMC8047013 DOI: 10.1038/s41598-021-87609-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Accepted: 03/31/2021] [Indexed: 01/31/2023] Open
Abstract
Cortical spreading depolarization (CSD) is a propagating wave of tissue depolarization characterized by a large increase of extracellular potassium concentration and prolonged subsequent electrical silencing of neurons. Waves of CSD arise spontaneously in various acute neurological settings, including migraine aura and ischemic stroke. Recently, we have reported that pan-inhibition of adrenergic receptors (AdRs) facilitates the normalization of extracellular potassium after acute photothrombotic stroke in mice. Here, we have extended that mechanistic study to ask whether AdR antagonists also modify the dynamics of KCl-induced CSD and post-CSD recovery in vivo. Spontaneous neural activity and KCl-induced CSD were visualized by cortex-wide transcranial Ca2+ imaging in G-CaMP7 transgenic mice. AdR antagonism decreased the recurrence of CSD waves and accelerated the post-CSD recovery of neural activity. Two-photon imaging revealed that astrocytes exhibited aberrant Ca2+ signaling after passage of the CSD wave. This astrocytic Ca2+ activity was diminished by the AdR antagonists. Furthermore, AdR pan-antagonism facilitated the normalization of the extracellular potassium level after CSD, which paralleled the recovery of neural activity. These observations add support to the proposal that neuroprotective effects of AdR pan-antagonism arise from accelerated normalization of extracellular K+ levels in the setting of acute brain injury.
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12
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Jia J, Jin H, Nan D, Yu W, Huang Y. New insights into targeting mitochondria in ischemic injury. Apoptosis 2021; 26:163-183. [PMID: 33751318 DOI: 10.1007/s10495-021-01661-5] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/19/2021] [Indexed: 12/15/2022]
Abstract
Stroke is the leading cause of adult disability and death worldwide. Mitochondrial dysfunction has been recognized as a marker of neuronal death during ischemic stroke. Maintaining the function of mitochondria is important for improving the survival of neurons and maintaining neuronal function. Damaged mitochondria induce neuronal cell apoptosis by releasing reactive oxygen species (ROS) and pro-apoptotic factors. Mitochondrial fission and fusion processes and mitophagy are of great importance to mitochondrial quality control. This paper reviews the dynamic changes in mitochondria, the roles of mitochondria in different cell types, and related signaling pathways in ischemic stroke. This review describes in detail the role of mitochondria in the process of neuronal injury and protection in cerebral ischemia, and integrates neuroprotective drugs targeting mitochondria in recent years, which may provide a theoretical basis for the progress of treatment of ischemic stroke. The potential of mitochondrial-targeted therapy is also emphasized, which provides valuable insights for clinical research.
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Affiliation(s)
- Jingjing Jia
- Department of Neurology, Peking University First Hospital, No.8 Xishiku Street, Xicheng District, Beijing, 100034, China
| | - Haiqiang Jin
- Department of Neurology, Peking University First Hospital, No.8 Xishiku Street, Xicheng District, Beijing, 100034, China
| | - Ding Nan
- Department of Neurology, Peking University First Hospital, No.8 Xishiku Street, Xicheng District, Beijing, 100034, China
| | - Weiwei Yu
- Department of Neurology, Peking University First Hospital, No.8 Xishiku Street, Xicheng District, Beijing, 100034, China
| | - Yining Huang
- Department of Neurology, Peking University First Hospital, No.8 Xishiku Street, Xicheng District, Beijing, 100034, China.
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13
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Okubo Y. Astrocytic Ca2+ signaling mediated by the endoplasmic reticulum in health and disease. J Pharmacol Sci 2020; 144:83-88. [DOI: 10.1016/j.jphs.2020.07.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Revised: 07/07/2020] [Accepted: 07/08/2020] [Indexed: 12/19/2022] Open
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14
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Kou ZW, Mo JL, Wu KW, Qiu MH, Huang YL, Tao F, Lei Y, Lv LL, Sun FY. Vascular endothelial growth factor increases the function of calcium-impermeable AMPA receptor GluA2 subunit in astrocytes via activation of protein kinase C signaling pathway. Glia 2019; 67:1344-1358. [PMID: 30883902 PMCID: PMC6594043 DOI: 10.1002/glia.23609] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Revised: 01/23/2019] [Accepted: 02/19/2019] [Indexed: 01/11/2023]
Abstract
Astrocytic calcium signaling plays pivotal roles in the maintenance of neural functions and neurovascular coupling in the brain. Vascular endothelial growth factor (VEGF), an original biological substance of vessels, regulates the movement of calcium and potassium ions across neuronal membrane. In this study, we investigated whether and how VEGF regulates glutamate-induced calcium influx in astrocytes. We used cultured astrocytes combined with living cell imaging to detect the calcium influx induced by glutamate. We found that VEGF quickly inhibited the glutamate/hypoxia-induced calcium influx, which was blocked by an AMPA receptor antagonist CNQX, but not D-AP5 or UBP310, NMDA and kainate receptor antagonist, respectively. VEGF increased phosphorylation of PKCα and AMPA receptor subunit GluA2 in astrocytes, and these effects were diminished by SU1498 or calphostin C, a PKC inhibitor. With the pHluorin assay, we observed that VEGF significantly increased membrane insertion and expression of GluA2, but not GluA1, in astrocytes. Moreover, siRNA-produced knockdown of GluA2 expression in astrocytes reversed the inhibitory effect of VEGF on glutamate-induced calcium influx. Together, our results suggest that VEGF reduces glutamate-induced calcium influx in astrocytes via enhancing PKCα-mediated GluA2 phosphorylation, which in turn promotes the membrane insertion and expression of GluA2 and causes AMPA receptors to switch from calcium-permeable to calcium-impermeable receptors, thereby inhibiting astrocytic calcium influx. The present study reveals that excitatory neurotransmitter glutamate-mediated astrocytic calcium influx can be regulated by vascular biological factor via activation of AMPA receptor GluA2 subunit and uncovers a novel coupling mechanism between astrocytes and endothelial cells within the neurovascular unit.
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Affiliation(s)
- Zeng-Wei Kou
- Department of Neurobiology and State Key Laboratory of Medical Neurobiology, School of Basic Medical Sciences, Shanghai Medical College, Fudan University, Shanghai, PR China.,Institute for Basic Research on Aging and Medicine of School of Basic Medical Sciences and National Clinical Research Center for Aging and Medicine, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, PR China
| | - Jia-Lin Mo
- Department of Neurobiology and State Key Laboratory of Medical Neurobiology, School of Basic Medical Sciences, Shanghai Medical College, Fudan University, Shanghai, PR China.,Institute for Basic Research on Aging and Medicine of School of Basic Medical Sciences and National Clinical Research Center for Aging and Medicine, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, PR China
| | - Kun-Wei Wu
- Department of Neurobiology and State Key Laboratory of Medical Neurobiology, School of Basic Medical Sciences, Shanghai Medical College, Fudan University, Shanghai, PR China.,Department of System Biology for Medicine, Institute of Biomedical Sciences, Shanghai Medical College, Fudan University, Shanghai, PR China
| | - Mei-Hong Qiu
- Department of Neurobiology and State Key Laboratory of Medical Neurobiology, School of Basic Medical Sciences, Shanghai Medical College, Fudan University, Shanghai, PR China.,Institute for Basic Research on Aging and Medicine of School of Basic Medical Sciences and National Clinical Research Center for Aging and Medicine, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, PR China
| | - Ya-Lin Huang
- Department of Neurobiology and State Key Laboratory of Medical Neurobiology, School of Basic Medical Sciences, Shanghai Medical College, Fudan University, Shanghai, PR China.,Department of System Biology for Medicine, Institute of Biomedical Sciences, Shanghai Medical College, Fudan University, Shanghai, PR China
| | - Feng Tao
- Department of Biomedical Sciences, Texas A&M University College of Dentistry, Dallas, Texas
| | - Yu Lei
- Department of Neurobiology and State Key Laboratory of Medical Neurobiology, School of Basic Medical Sciences, Shanghai Medical College, Fudan University, Shanghai, PR China.,Institute for Basic Research on Aging and Medicine of School of Basic Medical Sciences and National Clinical Research Center for Aging and Medicine, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, PR China
| | - Ling-Ling Lv
- Department of Neurobiology and State Key Laboratory of Medical Neurobiology, School of Basic Medical Sciences, Shanghai Medical College, Fudan University, Shanghai, PR China.,Institute for Basic Research on Aging and Medicine of School of Basic Medical Sciences and National Clinical Research Center for Aging and Medicine, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, PR China
| | - Feng-Yan Sun
- Department of Neurobiology and State Key Laboratory of Medical Neurobiology, School of Basic Medical Sciences, Shanghai Medical College, Fudan University, Shanghai, PR China.,Institute for Basic Research on Aging and Medicine of School of Basic Medical Sciences and National Clinical Research Center for Aging and Medicine, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, PR China.,Department of System Biology for Medicine, Institute of Biomedical Sciences, Shanghai Medical College, Fudan University, Shanghai, PR China
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15
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Okubo Y, Iino M. Visualization of astrocytic intracellular Ca 2+ mobilization. J Physiol 2019; 598:1671-1681. [PMID: 30825213 DOI: 10.1113/jp277609] [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: 12/25/2018] [Accepted: 02/06/2019] [Indexed: 11/08/2022] Open
Abstract
Astrocytes generate robust intracellular Ca2+ concentration changes (Ca2+ signals), which are assumed to regulate astrocytic functions that play crucial roles in the regulation of brain functions. One frequently used strategy for exploring the role of astrocytic Ca2+ signalling is the use of mice deficient in the type 2 inositol 1,4,5-trisphosphate receptor (IP3 R2). These IP3 R2-knockout (KO) mice are reportedly devoid of Ca2+ mobilization from the endoplasmic reticulum (ER) in astrocytes. However, they have shown no functional deficits in several studies, causing a heated debate as to the functional relevance of ER-mediated Ca2+ signalling in astrocytes. Recently, the assumption that Ca2+ mobilization from the ER is absent in IP3 R2-KO astrocytes has been re-evaluated using intraorganellar Ca2+ imaging techniques. The new results indicated that IP3 R2-independent Ca2+ release may generate Ca2+ nanodomains around the ER, which may help explain the absence of functional deficits in IP3 R2-KO mice.
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Affiliation(s)
- Yohei Okubo
- Department of Pharmacology, Graduate School of Medicine, The University of Tokyo, Tokyo, 133-0033, Japan
| | - Masamitsu Iino
- Division of Cellular and Molecular Pharmacology, Nihon University School of Medicine, Tokyo, 173-8610, Japan
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16
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Aberrant Calcium Signals in Reactive Astrocytes: A Key Process in Neurological Disorders. Int J Mol Sci 2019; 20:ijms20040996. [PMID: 30823575 PMCID: PMC6413203 DOI: 10.3390/ijms20040996] [Citation(s) in RCA: 85] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Revised: 02/20/2019] [Accepted: 02/21/2019] [Indexed: 02/06/2023] Open
Abstract
Astrocytes are abundant cells in the brain that regulate multiple aspects of neural tissue homeostasis by providing structural and metabolic support to neurons, maintaining synaptic environments and regulating blood flow. Recent evidence indicates that astrocytes also actively participate in brain functions and play a key role in brain disease by responding to neuronal activities and brain insults. Astrocytes become reactive in response to injury and inflammation, which is typically described as hypertrophy with increased expression of glial fibrillary acidic protein (GFAP). Reactive astrocytes are frequently found in many neurological disorders and are a hallmark of brain disease. Furthermore, reactive astrocytes may drive the initiation and progression of disease processes. Recent improvements in the methods to visualize the activity of reactive astrocytes in situ and in vivo have helped elucidate their functions. Ca2+ signals in reactive astrocytes are closely related to multiple aspects of disease and can be a good indicator of disease severity/state. In this review, we summarize recent findings concerning reactive astrocyte Ca2+ signals. We discuss the molecular mechanisms underlying aberrant Ca2+ signals in reactive astrocytes and the functional significance of aberrant Ca2+ signals in neurological disorders.
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17
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Okubo Y, Kanemaru K, Suzuki J, Kobayashi K, Hirose K, Iino M. Inositol 1,4,5-trisphosphate receptor type 2-independent Ca2+
release from the endoplasmic reticulum in astrocytes. Glia 2018; 67:113-124. [DOI: 10.1002/glia.23531] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Revised: 08/13/2018] [Accepted: 08/15/2018] [Indexed: 12/13/2022]
Affiliation(s)
- Yohei Okubo
- Department of Pharmacology; Graduate School of Medicine, The University of Tokyo; Tokyo Japan
| | - Kazunori Kanemaru
- Department of Pharmacology; Graduate School of Medicine, The University of Tokyo; Tokyo Japan
- Department of Cellular and Molecular Pharmacology; Nihon University School of Medicine; Tokyo Japan
| | - Junji Suzuki
- Department of Physiology; University of California San Francisco; San Francisco California
| | - Kenta Kobayashi
- Section of Viral Vector Development; National Institute for Physiological Sciences; Okazaki Japan
- The Graduate University for Advanced Studies (SOKENDAI); Hayama Japan
| | - Kenzo Hirose
- Department of Neurobiology; Graduate School of Medicine, The University of Tokyo; Tokyo Japan
| | - Masamitsu Iino
- Department of Cellular and Molecular Pharmacology; Nihon University School of Medicine; Tokyo Japan
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18
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Gómez-Gonzalo M, Zehnder T, Requie LM, Bezzi P, Carmignoto G. Insights into the release mechanism of astrocytic glutamate evoking in neurons NMDA receptor-mediated slow depolarizing inward currents. Glia 2018; 66:2188-2199. [DOI: 10.1002/glia.23473] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Revised: 04/27/2018] [Accepted: 05/25/2018] [Indexed: 12/19/2022]
Affiliation(s)
- Marta Gómez-Gonzalo
- Neuroscience Institute, National Research Council (CNR) and Department of Biomedical Sciences; University of Padova; Padova Italy
| | - Tamara Zehnder
- Department of Fundamental Neurosciences; University of Lausanne; Lausanne Switzerland
| | - Linda Maria Requie
- Neuroscience Institute, National Research Council (CNR) and Department of Biomedical Sciences; University of Padova; Padova Italy
| | - Paola Bezzi
- Department of Fundamental Neurosciences; University of Lausanne; Lausanne Switzerland
| | - Giorgio Carmignoto
- Neuroscience Institute, National Research Council (CNR) and Department of Biomedical Sciences; University of Padova; Padova Italy
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19
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Stokum JA, Kwon MS, Woo SK, Tsymbalyuk O, Vennekens R, Gerzanich V, Simard JM. SUR1-TRPM4 and AQP4 form a heteromultimeric complex that amplifies ion/water osmotic coupling and drives astrocyte swelling. Glia 2017; 66:108-125. [PMID: 28906027 DOI: 10.1002/glia.23231] [Citation(s) in RCA: 85] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Revised: 07/23/2017] [Accepted: 08/23/2017] [Indexed: 12/17/2022]
Abstract
Astrocyte swelling occurs after central nervous system injury and contributes to brain swelling, which can increase mortality. Mechanisms proffered to explain astrocyte swelling emphasize the importance of either aquaporin-4 (AQP4), an astrocyte water channel, or of Na+ -permeable channels, which mediate cellular osmolyte influx. However, the spatio-temporal functional interactions between AQP4 and Na+ -permeable channels that drive swelling are poorly understood. We hypothesized that astrocyte swelling after injury is linked to an interaction between AQP4 and Na+ -permeable channels that are newly upregulated. Here, using co-immunoprecipitation and Förster resonance energy transfer, we report that AQP4 physically co-assembles with the sulfonylurea receptor 1-transient receptor potential melastatin 4 (SUR1-TRPM4) monovalent cation channel to form a novel heteromultimeric water/ion channel complex. In vitro cell-swelling studies using calcein fluorescence imaging of COS-7 cells expressing various combinations of AQP4, SUR1, and TRPM4 showed that the full tripartite complex, comprised of SUR1-TRPM4-AQP4, was required for fast, high-capacity transmembrane water transport that drives cell swelling, with these findings corroborated in cultured primary astrocytes. In a murine model of brain edema involving cold-injury to the cerebellum, we found that astrocytes newly upregulate SUR1-TRPM4, that AQP4 co-associates with SUR1-TRPM4, and that genetic inactivation of the solute pore of the SUR1-TRPM4-AQP4 complex blocked in vivo astrocyte swelling measured by diolistic labeling, thereby corroborating our in vitro functional studies. Together, these findings demonstrate a novel molecular mechanism involving the SUR1-TRPM4-AQP4 complex to account for bulk water influx during astrocyte swelling. These findings have broad implications for the understanding and treatment of AQP4-mediated pathological conditions.
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Affiliation(s)
- Jesse A Stokum
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, Maryland, 21201-1595
| | - Min S Kwon
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, Maryland, 21201-1595
| | - Seung K Woo
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, Maryland, 21201-1595
| | - Orest Tsymbalyuk
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, Maryland, 21201-1595
| | - Rudi Vennekens
- Department of Cellular and Molecular Medicine, Laboratory of Ion Channel Research, Katholieke Universiteit Leuven, Leuven, 3000, Belgium
| | - Volodymyr Gerzanich
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, Maryland, 21201-1595
| | - J Marc Simard
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, Maryland, 21201-1595.,Department of Pathology, University of Maryland School of Medicine, Baltimore, Maryland, 21201-1595.,Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland, 21201-1595
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20
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Kovács A, Pál B. Astrocyte-Dependent Slow Inward Currents (SICs) Participate in Neuromodulatory Mechanisms in the Pedunculopontine Nucleus (PPN). Front Cell Neurosci 2017; 11:16. [PMID: 28203147 PMCID: PMC5285330 DOI: 10.3389/fncel.2017.00016] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2016] [Accepted: 01/18/2017] [Indexed: 11/13/2022] Open
Abstract
Slow inward currents (SICs) are known as excitatory events of neurons caused by astrocytic glutamate release and consequential activation of neuronal extrasynaptic NMDA receptors. In the present article we investigate the role of these astrocyte-dependent excitatory events on a cholinergic nucleus of the reticular activating system (RAS), the pedunculopontine nucleus (PPN). It is well known about this and other elements of the RAS, that they do not only give rise to neuromodulatory innervation of several areas, but also targets neuromodulatory actions from other members of the RAS or factors providing the homeostatic drive for sleep. Using slice electrophysiology, optogenetics and morphological reconstruction, we revealed that SICs are present in a population of PPN neurons. The frequency of SICs recorded on PPN neurons was higher when the soma of the given neuron was close to an astrocytic soma. SICs do not appear simultaneously on neighboring neurons, thus it is unlikely that they synchronize neuronal activity in this structure. Occurrence of SICs is regulated by cannabinoid, muscarinic and serotonergic neuromodulatory mechanisms. In most cases, SICs occurred independently from tonic neuronal currents. SICs were affected by different neuromodulatory agents in a rather uniform way: if control SIC activity was low, the applied drugs increased it, but if SIC activity was increased in control, the same drugs lowered it. SICs of PPN neurons possibly represent a mechanism which elicits network-independent spikes on certain PPN neurons; forming an alternative, astrocyte-dependent pathway of neuromodulatory mechanisms.
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Affiliation(s)
- Adrienn Kovács
- Department of Physiology, Faculty of Medicine, University of Debrecen Debrecen, Hungary
| | - Balázs Pál
- Department of Physiology, Faculty of Medicine, University of Debrecen Debrecen, Hungary
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21
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Neurodegeneration and Glial Response after Acute Striatal Stroke: Histological Basis for Neuroprotective Studies. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2016; 2016:3173564. [PMID: 28090244 PMCID: PMC5165163 DOI: 10.1155/2016/3173564] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Revised: 09/26/2016] [Accepted: 10/12/2016] [Indexed: 11/24/2022]
Abstract
Stroke is a leading cause of death and neurological disability worldwide and striatal ischemic stroke is frequent in humans due to obstruction of middle cerebral artery. Several pathological events underlie damage progression and a comprehensive description of the pathological features following experimental stroke in both acute and chronic survival times is a necessary step for further functional studies. Here, we explored the patterns of microglial activation, astrocytosis, oligodendrocyte damage, myelin impairment, and Nogo-A immunoreactivity between 3 and 30 postlesion days (PLDs) after experimental striatal stroke in adult rats induced by microinjections of endothelin-1 (ET-1). The focal ischemia induced tissue loss concomitant with intense microglia activation between 3 and 14 PLDs (maximum at 7 PLDs), decreasing afterward. Astrocytosis was maximum around 7 PLDs. Oligodendrocyte damage and Nogo-A upregulation were higher at 3 PLDs. Myelin impairment was maximum between 7 and 14 PLDs. Nogo-A expression was higher in the first week in comparison to control. The results add important histopathological features of ET-1 induced stroke in subacute and chronic survival times. In addition, the establishment of the temporal evolution of these neuropathological events is an important step for future studies seeking suitable neuroprotective drugs targeting neuroinflammation and white matter damage.
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22
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Targeting Glial Mitochondrial Function for Protection from Cerebral Ischemia: Relevance, Mechanisms, and the Role of MicroRNAs. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2016; 2016:6032306. [PMID: 27777645 PMCID: PMC5061974 DOI: 10.1155/2016/6032306] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/24/2016] [Revised: 08/21/2016] [Accepted: 08/31/2016] [Indexed: 12/11/2022]
Abstract
Astrocytes and microglia play crucial roles in the response to cerebral ischemia and are effective targets for stroke therapy in animal models. MicroRNAs (miRs) are important posttranscriptional regulators of gene expression that function by inhibiting the translation of select target genes. In astrocytes, miR expression patterns regulate mitochondrial function in response to oxidative stress via targeting of Bcl2 and heat shock protein 70 family members. Mitochondria play an active role in microglial activation, and miRs regulate the microglial neuroinflammatory response. As endogenous miR expression patterns can be altered with exogenous mimics and inhibitors, miR-targeted therapies represent a viable intervention to optimize glial mitochondrial function and improve clinical outcome following cerebral ischemia. In the present article, we review the role that astrocytes and microglia play in neuronal function and fate following ischemic stress, discuss the relevance of mitochondria in the glial response to injury, and present current evidence implicating miRs as critical regulators in the glial mitochondrial response to cerebral ischemia.
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23
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Curcio M, Salazar IL, Mele M, Canzoniero LMT, Duarte CB. Calpains and neuronal damage in the ischemic brain: The swiss knife in synaptic injury. Prog Neurobiol 2016; 143:1-35. [PMID: 27283248 DOI: 10.1016/j.pneurobio.2016.06.001] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2015] [Revised: 03/22/2016] [Accepted: 05/09/2016] [Indexed: 12/26/2022]
Abstract
The excessive extracellular accumulation of glutamate in the ischemic brain leads to an overactivation of glutamate receptors with consequent excitotoxic neuronal death. Neuronal demise is largely due to a sustained activation of NMDA receptors for glutamate, with a consequent increase in the intracellular Ca(2+) concentration and activation of calcium- dependent mechanisms. Calpains are a group of Ca(2+)-dependent proteases that truncate specific proteins, and some of the cleavage products remain in the cell, although with a distinct function. Numerous studies have shown pre- and post-synaptic effects of calpains on glutamatergic and GABAergic synapses, targeting membrane- associated proteins as well as intracellular proteins. The resulting changes in the presynaptic proteome alter neurotransmitter release, while the cleavage of postsynaptic proteins affects directly or indirectly the activity of neurotransmitter receptors and downstream mechanisms. These alterations also disturb the balance between excitatory and inhibitory neurotransmission in the brain, with an impact in neuronal demise. In this review we discuss the evidence pointing to a role for calpains in the dysregulation of excitatory and inhibitory synapses in brain ischemia, at the pre- and post-synaptic levels, as well as the functional consequences. Although targeting calpain-dependent mechanisms may constitute a good therapeutic approach for stroke, specific strategies should be developed to avoid non-specific effects given the important regulatory role played by these proteases under normal physiological conditions.
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Affiliation(s)
- Michele Curcio
- CNC - Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal
| | - Ivan L Salazar
- CNC - Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal; Doctoral Programme in Experimental Biology and Biomedicine, Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal; Institute for Interdisciplinary Research, University of Coimbra (IIIUC), 3030-789 Coimbra, Portugal
| | - Miranda Mele
- CNC - Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal
| | | | - Carlos B Duarte
- CNC - Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal; Department of Life Sciences, University of Coimbra, 3000-456 Coimbra, Portugal.
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24
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Khacho P, Wang B, Bergeron R. The Good and Bad Sides of NAAG. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2016; 76:311-49. [PMID: 27288081 DOI: 10.1016/bs.apha.2016.01.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Why has such a small peptide been the source of controversy in neuroscience over the last 5 decades? Is N-acetyl-aspartyl-glutamate (NAAG) a neurotransmitter? Is NAAG located in neuronal tissue or in astrocytes? Is NAAG involved in neuropsychiatric and neurodegenerative disorders? Is NAAG therapeutically beneficial in the treatment of stroke or in initiating cascades of events leading to psychosis? After many years of intense research there is no clear consensus within the scientific community on how NAAG behaves in the brain. One of the major controversies about NAAG is its physiological action at N-methyl-d-aspartate (NMDA) receptors. While some researchers strongly argue that NAAG acts as a weak agonist at NMDA receptors, others have suggested that NAAG could behave as a potent antagonist. Published data from our laboratory demonstrate that the effect of NAAG on NMDA receptors could be influenced by a number of factors including the subcellular localization and subunit composition of NMDA receptors, as well as protons. In this chapter, we will summarize the knowledge of the literature on NAAG, however, we will place emphasis on our recently published data. More specifically, we have reported interesting findings on the effects of NAAG on NMDA receptors at synaptic and extrasynaptic sites using a pharmacological paradigm to distinguish the two populations of NMDA receptors. Additionally, we have evaluated the role of NAAG on GluN2A- and GluN2B-containing NMDA receptors using a HEK293 cell recombinant system. Finally, we have studied the effects of NAAG on GluN2A- and GluN2B-containing NMDA receptors in different extracellular pH conditions. We believe that our findings could potentially resolve some aspects of the debate regarding the role of NAAG at NMDA receptors.
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Affiliation(s)
- P Khacho
- University of Ottawa, Ottawa, ON, Canada
| | - B Wang
- University of Ottawa, Ottawa, ON, Canada
| | - R Bergeron
- University of Ottawa, Ottawa, ON, Canada; Ottawa Hospital Research Institute, Ottawa, ON, Canada.
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Chang R, Zhou R, Qi X, Wang J, Wu F, Yang W, Zhang W, Sun T, Li Y, Yu J. Protective effects of aloin on oxygen and glucose deprivation-induced injury in PC12 cells. Brain Res Bull 2016; 121:75-83. [PMID: 26772628 DOI: 10.1016/j.brainresbull.2016.01.001] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Revised: 12/28/2015] [Accepted: 01/04/2016] [Indexed: 01/11/2023]
Abstract
The present study aims to determine whether aloin could protect cells from ischemic and reperfusion injury in vitro and to elucidate the related mechanisms. Oxygen and glucose deprivation model in PC12 cells was used in the present study. 2-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), lactate dehydrogenase (LDH) assay and Hoechst 33342 nuclear staining were used to evaluate the protective effects of aloin, at concentrations of 10, 20, or 40 μg/mL in PC12 cells. PCR was applied to detect fluorescence caspase-3, Bax and Bcl-2 mRNA expression in PC12 cells. The contents of malondialdehyde (MDA), superoxide dismutase (SOD) activity were evaluated by biochemical method. The concentration of intracellular-free calcium [Ca(2+)]i, mitochondrial membrane potential (MMP) were determined to estimate the degree of neuronal damage. It was shown that aloin (10, 20, and 40 μg/mL) significantly attenuated PC12 cells damage with characteristics of an increased injured cells absorbance of MTT and releases of LDH, decreasing cell apoptosis, and antagonizing decreases in SOD activity and increase in MDA level induced by OGD-reoxygenation. Meanwhile pretreatment with aloin significantly reduced injury-induced intracellular ROS, increased MMP (P<0.01), but it inhibited [Ca(2+)]i (P<0.01) elevation in a dose-dependent manner. Furthermore, pre-treatment with aloin significantly up-regulated Bcl-2 mRNA expression, down-regulated Bax mRNA expression and consequently activated caspase-3 mRNA expression in a dose-dependent manner. The results indicated that the protection of aloin on OGD-induced apoptosis in PC12 cells is associated with its suppression on OGD-induced oxidative stress and protection on mitochondrial function and inhibition of caspase activity. Alion could be a promising candidate in the development of a novel class of anti-ischemic agent.
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Affiliation(s)
- Renyuan Chang
- Department of Pharmacology, College of Pharmacy, Ningxia Medical University, Yinchuan, China
| | - Ru Zhou
- Department of Pharmacology, College of Pharmacy, Ningxia Medical University, Yinchuan, China
| | - Xue Qi
- Department of Pharmacology, College of Pharmacy, Ningxia Medical University, Yinchuan, China
| | - Jing Wang
- Department of Pharmacology, College of Pharmacy, Ningxia Medical University, Yinchuan, China
| | - Fan Wu
- Department of Pharmacology, College of Pharmacy, Ningxia Medical University, Yinchuan, China
| | - Wenli Yang
- Department of Pharmacology, College of Pharmacy, Ningxia Medical University, Yinchuan, China
| | - Wannian Zhang
- Department of Pharmacology, College of Pharmacy, Ningxia Medical University, Yinchuan, China
| | - Tao Sun
- Ningxia Key Lab of Craniocerebral Diseases of Ningxia Hui Autonomous Region, Yinchuan, China
| | - Yuxiang Li
- College of Nursing, Ningxia Medical University, Yinchuan, China.
| | - Jianqiang Yu
- Department of Pharmacology, College of Pharmacy, Ningxia Medical University, Yinchuan, China; Ningxia Hui Medicine Modern Engineering Research Center, Ningxia Medical University, Yinchuan, China.
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26
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Li JM, Zhang Y, Tang L, Chen YH, Gao Q, Bao MH, Xiang J, Lei DL. Effects of triptolide on hippocampal microglial cells and astrocytes in the APP/PS1 double transgenic mouse model of Alzheimer's disease. Neural Regen Res 2016; 11:1492-1498. [PMID: 27857756 PMCID: PMC5090855 DOI: 10.4103/1673-5374.191224] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
The principal pathology of Alzheimer's disease includes neuronal extracellular deposition of amyloid-beta peptides and formation of senile plaques, which in turn induce neuroinflammation in the brain. Triptolide, a natural extract from the vine-like herb Tripterygium wilfordii Hook F, has potent anti-inflammatory and immunosuppressive efficacy. Therefore, we determined if triptolide can inhibit activation and proliferation of microglial cells and astrocytes in the APP/PS1 double transgenic mouse model of Alzheimer's disease. We used 1 or 5 μg/kg/d triptolide to treat APP/PS1 double transgenic mice (aged 4-4.5 months) for 45 days. Unbiased stereology analysis found that triptolide dose-dependently reduced the total number of microglial cells, and transformed microglial cells into the resting state. Further, triptolide (5 μg/kg/d) also reduced the total number of hippocampal astrocytes. Our in vivo test results indicate that triptolide suppresses activation and proliferation of microglial cells and astrocytes in the hippocampus of APP/PS1 double transgenic mice with Alzheimer's disease.
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Affiliation(s)
- Jian-Ming Li
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan Province, China; Department of Anatomy and Neurobiology, Central South University, School of Basic Medical Science, Changsha, Hunan Province, China; Neuroscience Research Center, Changsha Medical University, Changsha, Hunan Province, China; Department of Anatomy, Changsha Medical University, Changsha, Hunan Province, China
| | - Yan Zhang
- Neuroscience Research Center, Changsha Medical University, Changsha, Hunan Province, China
| | - Liang Tang
- Neuroscience Research Center, Changsha Medical University, Changsha, Hunan Province, China
| | - Yong-Heng Chen
- Neuroscience Research Center, Changsha Medical University, Changsha, Hunan Province, China
| | - Qian Gao
- Neuroscience Research Center, Changsha Medical University, Changsha, Hunan Province, China
| | - Mei-Hua Bao
- Neuroscience Research Center, Changsha Medical University, Changsha, Hunan Province, China
| | - Ju Xiang
- Neuroscience Research Center, Changsha Medical University, Changsha, Hunan Province, China
| | - De-Liang Lei
- Department of Anatomy and Neurobiology, Central South University, School of Basic Medical Science, Changsha, Hunan Province, China
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Gap Junction Intercellular Communication Mediates Ammonia-Induced Neurotoxicity. Neurotox Res 2015; 29:314-24. [PMID: 26646155 DOI: 10.1007/s12640-015-9581-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Revised: 11/20/2015] [Accepted: 11/24/2015] [Indexed: 12/21/2022]
Abstract
Astrocytes are important brain targets of ammonia, a neurotoxin implicated in the development of hepatic encephalopathy. During hyperammonemia, the pivotal role of astrocytes in brain function and homeostasis is impaired. These cells are abundantly interconnected by gap junctions (GJ), which are intercellular channels that allow the exchange of signaling molecules and metabolites. This communication may also increase cellular vulnerability during injuries, while GJ uncoupling could limit the extension of a lesion. Therefore, the current study was performed to investigate whether astrocyte coupling through GJ contributes to ammonia-induced cytotoxicity. We found that carbenoxolone (CBX), an effective GJ blocker, prevented the following effects induced by ammonia in astrocyte primary cultures: (1) decrease in cell viability and membrane integrity; (2) increase in reactive oxygen species production; (3) decrease in GSH intracellular levels; (4) GS activity; (5) pro-inflammatory cytokine release. On the other hand, CBX had no effect on C6 astroglial cells, which are poorly coupled via GJ. To our knowledge, this study provides the first evidence that GJ play a role in ammonia-induced cytotoxicity. Although more studies in vivo are required to confirm our hypothesis, our data suggest that GJ communication between astrocytes may transmit damage signals and excitotoxic components from unhealthy to normal cells, thereby contributing to the propagation of the neurotoxicity of ammonia.
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Li H, Xie Y, Zhang N, Yu Y, Zhang Q, Ding S. Disruption of IP₃R2-mediated Ca²⁺ signaling pathway in astrocytes ameliorates neuronal death and brain damage while reducing behavioral deficits after focal ischemic stroke. Cell Calcium 2015; 58:565-76. [PMID: 26433454 DOI: 10.1016/j.ceca.2015.09.004] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Revised: 09/19/2015] [Accepted: 09/21/2015] [Indexed: 12/12/2022]
Abstract
Inositol trisphosphate receptor (IP3R)-mediated intracellular Ca(2+) increase is the major Ca(2+) signaling pathway in astrocytes in the central nervous system (CNS). Ca(2+) increases in astrocytes have been found to modulate neuronal function through gliotransmitter release. We previously demonstrated that astrocytes exhibit enhanced Ca(2+) signaling in vivo after photothrombosis (PT)-induced ischemia, which is largely due to the activation of G-protein coupled receptors (GPCRs). The aim of this study is to investigate the role of astrocytic IP3R-mediated Ca(2+) signaling in neuronal death, brain damage and behavior outcomes after PT. For this purpose, we conducted experiments using homozygous type 2 IP3R (IP3R2) knockout (KO) mice. Histological and immunostaining studies showed that IP3R2 KO mice were indeed deficient in IP3R2 in astrocytes and exhibited normal brain cytoarchitecture. IP3R2 KO mice also had the same densities of S100β+ astrocytes and NeuN+ neurons in the cortices, and exhibited the same glial fibrillary acidic protein (GFAP) and glial glutamate transporter (GLT-1) levels in the cortices and hippocampi as compared with wild type (WT) mice. Two-photon (2-P) imaging showed that IP3R2 KO mice did not exhibit ATP-induced Ca(2+) waves in vivo in the astrocytic network, which verified the disruption of IP3R-mediated Ca(2+) signaling in astrocytes of these mice. When subject to PT, IP3R2 KO mice had smaller infarction than WT mice in acute and chronic phases of ischemia. IP3R2 KO mice also exhibited less neuronal apoptosis, reactive astrogliosis, and tissue loss than WT mice. Behavioral tests, including cylinder, hanging wire, pole and adhesive tests, showed that IP3R2 KO mice exhibited reduced functional deficits after PT. Collectively, our study demonstrates that disruption of astrocytic Ca(2+) signaling by deleting IP3R2s has beneficial effects on neuronal and brain protection and functional deficits after stroke. These findings reveal a novel non-cell-autonomous neuronal and brain protective function of astrocytes in ischemic stroke, whereby suggest that the astrocytic IP3R2-mediated Ca(2+) signaling pathway might be a promising target for stroke therapy.
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Affiliation(s)
- Hailong Li
- Dalton Cardiovascular Research Center, University of Missouri-Columbia, MO 65211, United States; Department of Bioengineering, University of Missouri-Columbia, MO 65211, United States
| | - Yicheng Xie
- Dalton Cardiovascular Research Center, University of Missouri-Columbia, MO 65211, United States; Department of Bioengineering, University of Missouri-Columbia, MO 65211, United States
| | - Nannan Zhang
- Dalton Cardiovascular Research Center, University of Missouri-Columbia, MO 65211, United States
| | - Yang Yu
- Department of Bioengineering, University of Missouri-Columbia, MO 65211, United States
| | - Qiao Zhang
- Department of Bioengineering, University of Missouri-Columbia, MO 65211, United States
| | - Shinghua Ding
- Dalton Cardiovascular Research Center, University of Missouri-Columbia, MO 65211, United States; Department of Bioengineering, University of Missouri-Columbia, MO 65211, United States.
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Choudhury GR, Ding S. Reactive astrocytes and therapeutic potential in focal ischemic stroke. Neurobiol Dis 2015; 85:234-244. [PMID: 25982835 DOI: 10.1016/j.nbd.2015.05.003] [Citation(s) in RCA: 175] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2015] [Revised: 03/26/2015] [Accepted: 05/08/2015] [Indexed: 12/17/2022] Open
Abstract
Astrocytes are specialized and the most abundant cell type in the central nervous system (CNS). They play important roles in the physiology of the brain. Astrocytes are also critically involved in many CNS disorders including focal ischemic stroke, the leading cause of brain injury and death in patients. One of the prominent pathological features of a focal ischemic stroke is reactive astrogliosis and glial scar formation. Reactive astrogliosis is accompanied with changes in morphology, proliferation, and gene expression in the reactive astrocytes. This study provides an overview of the most recent advances in astrocytic Ca(2+) signaling, spatial, and temporal dynamics of the morphology and proliferation of reactive astrocytes as well as signaling pathways involved in the reactive astrogliosis after ischemic stroke based on results from experimental studies performed in various animal models. This review also discusses the therapeutic potential of reactive astrocytes in focal ischemic stroke. As reactive astrocytes exhibit high plasticity, we suggest that modulation of local reactive astrocytes is a promising strategy for cell-based stroke therapy.
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Affiliation(s)
| | - Shinghua Ding
- Dalton Cardiovascular Research Center, Columbia, MO, USA; Department of Bioengineering, University of Missouri-Columbia, Columbia, MO 65211, USA.
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30
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Abstract
Astrocytes have been found to play important roles in physiology being fundamental for ionic homeostasis and glutamate clearance from the synaptic cleft by their plasma membrane glutamate transporters. Astrocytes are electrically non-excitable, but they exhibit Ca(2+) signaling, which now has been demonstrated to serve as an indirect mediator of neuron-glia bidirectional interactions through gliotransmission via tripartite synapses and to modulate synaptic function and plasticity. Spontaneous astrocytic Ca(2+) signaling was observed in vivo. Intercellular Ca(2+) waves in astrocytes can be evoked by a variety of stimulations. Astrocytes are critically involved in many pathological conditions including ischemic stroke. For example, it is well known that astrocytes become reactive and form glial scar after stroke. In animal models of some brain disorders, astrocytes have been shown to exhibit enhanced Ca(2+) excitability featured as regenerative intercellular Ca(2+) waves. This chapter briefly summarizes astrocytic Ca(2+) signaling pathways under normal conditions and in experimental in vitro and in vivo ischemic models. It discusses the possible mechanisms and therapeutic implication underlying the enhanced astrocytic Ca(2+) excitability in stroke.
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Affiliation(s)
- Shinghua Ding
- Dalton Cardiovascular Research Center, Department of Bioengineering, University of Missouri-Columbia, 134 Research Park Drive, Columbia, MO, 65211, USA,
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31
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Tukhovskaya EA, Turovsky EA, Turovskaya MV, Levin SG, Murashev AN, Zinchenko VP, Godukhin OV. Anti-inflammatory cytokine interleukin-10 increases resistance to brain ischemia through modulation of ischemia-induced intracellular Ca²⁺ response. Neurosci Lett 2014; 571:55-60. [PMID: 24796809 DOI: 10.1016/j.neulet.2014.04.046] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2014] [Revised: 04/17/2014] [Accepted: 04/25/2014] [Indexed: 10/25/2022]
Abstract
It is suggested that anti-inflammatory cytokine interleukin-10 (IL-10) mediates the delayed protective effects through activation of Jak-Stat3, PI3K-Akt and NF-κB signaling pathways. However, our previous experiments have demonstrated that IL-10 is capable to exert the rapid neuroprotective action through modulation of hypoxia-induced intracellular Ca(2+) ([Ca(2+)]i) response. The first purpose of the present study was to evaluate the neuroprotective effects of IL-10 using three models of the ischemic insults in rats: permanent middle cerebral artery occlusion, ischemia in acute hippocampal slices in vitro and ischemia in cultured hippocampal cells in vitro. The second purpose of the study was to elucidate a role of [Ca(2+)]i changes in the mechanisms underlying IL-10 elicited protection of neurons and astrocytes from ischemia-induced death in cultures of primary hippocampal cells. The data presented here shown that anti-inflammatory cytokine IL-10 is capable to induce a resistance of the brain cells to ischemia-evoked damages in in vivo and in vitro models of the ischemic insults in rats. This protective effect in cultured hippocampal cells is developed rapidly after application of IL-10 and strongly associated with the IL-10 elicited elimination of [Ca(2+)]i response to ischemia. Thus, our results provide the evidence that anti-inflammatory cytokine IL-10, in addition to an activation of the canonical signaling pathways, is capable to exert the rapid neuroprotective effects through transcription-independent modulation of ischemia-induced intracellular Ca(2+) responses in the brain cells.
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Affiliation(s)
- Elena A Tukhovskaya
- Branch of Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry of Russian Academy of Sciences, Pushchino, Russia
| | - Egor A Turovsky
- Institute of Cell Biophysics of Russian Academy of Sciences, Pushchino, Russia
| | - Maria V Turovskaya
- Institute of Cell Biophysics of Russian Academy of Sciences, Pushchino, Russia
| | - Sergei G Levin
- Institute of Theoretical and Experimental Biophysics of Russian Academy of Sciences, Pushchino, Russia
| | - Arkady N Murashev
- Branch of Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry of Russian Academy of Sciences, Pushchino, Russia
| | - Valery P Zinchenko
- Institute of Cell Biophysics of Russian Academy of Sciences, Pushchino, Russia
| | - Oleg V Godukhin
- Institute of Theoretical and Experimental Biophysics of Russian Academy of Sciences, Pushchino, Russia.
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De Bock M, Decrock E, Wang N, Bol M, Vinken M, Bultynck G, Leybaert L. The dual face of connexin-based astroglial Ca(2+) communication: a key player in brain physiology and a prime target in pathology. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2014; 1843:2211-32. [PMID: 24768716 DOI: 10.1016/j.bbamcr.2014.04.016] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 01/31/2014] [Revised: 04/11/2014] [Accepted: 04/12/2014] [Indexed: 12/21/2022]
Abstract
For decades, studies have been focusing on the neuronal abnormalities that accompany neurodegenerative disorders. Yet, glial cells are emerging as important players in numerous neurological diseases. Astrocytes, the main type of glia in the central nervous system , form extensive networks that physically and functionally connect neuronal synapses with cerebral blood vessels. Normal brain functioning strictly depends on highly specialized cellular cross-talk between these different partners to which Ca(2+), as a signaling ion, largely contributes. Altered intracellular Ca(2+) levels are associated with neurodegenerative disorders and play a crucial role in the glial responses to injury. Intracellular Ca(2+) increases in single astrocytes can be propagated toward neighboring cells as intercellular Ca(2+) waves, thereby recruiting a larger group of cells. Intercellular Ca(2+) wave propagation depends on two, parallel, connexin (Cx) channel-based mechanisms: i) the diffusion of inositol 1,4,5-trisphosphate through gap junction channels that directly connect the cytoplasm of neighboring cells, and ii) the release of paracrine messengers such as glutamate and ATP through hemichannels ('half of a gap junction channel'). This review gives an overview of the current knowledge on Cx-mediated Ca(2+) communication among astrocytes as well as between astrocytes and other brain cell types in physiology and pathology, with a focus on the processes of neurodegeneration and reactive gliosis. Research on Cx-mediated astroglial Ca(2+) communication may ultimately shed light on the development of targeted therapies for neurodegenerative disorders in which astrocytes participate. This article is part of a Special Issue entitled: Calcium signaling in health and disease. Guest Editors: Geert Bultynck, Jacques Haiech, Claus W. Heizmann, Joachim Krebs, and Marc Moreau.
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Affiliation(s)
- Marijke De Bock
- Department of Basic Medical Sciences, Physiology group, Faculty of Medicine and Health Sciences, Ghent University, B-9000 Ghent, Belgium
| | - Elke Decrock
- Department of Basic Medical Sciences, Physiology group, Faculty of Medicine and Health Sciences, Ghent University, B-9000 Ghent, Belgium.
| | - Nan Wang
- Department of Basic Medical Sciences, Physiology group, Faculty of Medicine and Health Sciences, Ghent University, B-9000 Ghent, Belgium
| | - Mélissa Bol
- Department of Basic Medical Sciences, Physiology group, Faculty of Medicine and Health Sciences, Ghent University, B-9000 Ghent, Belgium
| | - Mathieu Vinken
- Department of Toxicology, Center for Pharmaceutical Research, Faculty of Medicine and Pharmacy, Vrije Universiteit Brussel, B-1090 Brussels, Belgium
| | - Geert Bultynck
- Department of Cellular and Molecular Medicine, Laboratory of Molecular and Cellular Signalling, KULeuven, Campus Gasthuisberg O/N-I bus 802, B-3000 Leuven, Belgium
| | - Luc Leybaert
- Department of Basic Medical Sciences, Physiology group, Faculty of Medicine and Health Sciences, Ghent University, B-9000 Ghent, Belgium
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Parsons M, Raymond L. Extrasynaptic NMDA Receptor Involvement in Central Nervous System Disorders. Neuron 2014; 82:279-93. [DOI: 10.1016/j.neuron.2014.03.030] [Citation(s) in RCA: 286] [Impact Index Per Article: 28.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/24/2014] [Indexed: 12/21/2022]
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Shinotsuka T, Yasui M, Nuriya M. Astrocytic gap junctional networks suppress cellular damage in an in vitro model of ischemia. Biochem Biophys Res Commun 2014; 444:171-6. [PMID: 24440704 DOI: 10.1016/j.bbrc.2014.01.035] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2013] [Accepted: 01/10/2014] [Indexed: 10/25/2022]
Abstract
Astrocytes play pivotal roles in both the physiology and the pathophysiology of the brain. They communicate with each other via extracellular messengers as well as through gap junctions, which may exacerbate or protect against pathological processes in the brain. However, their roles during the acute phase of ischemia and the underlying cellular mechanisms remain largely unknown. To address this issue, we imaged changes in the intracellular calcium concentration ([Ca(2+)]i) in astrocytes in mouse cortical slices under oxygen/glucose deprivation (OGD) condition using two-photon microscopy. Under OGD, astrocytes showed [Ca(2+)]i oscillations followed by larger and sustained [Ca(2+)]i increases. While the pharmacological blockades of astrocytic receptors for glutamate and ATP had no effect, the inhibitions of gap junctional intercellular coupling between astrocytes significantly advanced the onset of the sustained [Ca(2+)]i increase after OGD exposure. Interestingly, the simultaneous recording of the neuronal membrane potential revealed that the onset of the sustained [Ca(2+)]i increase in astrocytes was synchronized with the appearance of neuronal anoxic depolarization. Furthermore, the blockade of gap junctional coupling resulted in a concurrent faster appearance of neuronal depolarizations, which remain synchronized with the sustained [Ca(2+)]i increase in astrocytes. These results indicate that astrocytes delay the appearance of the pathological responses of astrocytes and neurons through their gap junction-mediated intercellular network under OGD. Thus, astrocytic gap junctional networks provide protection against tissue damage during the acute phase of ischemia.
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Affiliation(s)
- Takanori Shinotsuka
- Department of Pharmacology, School of Medicine, Keio University, 35 Shinanomachi, Shinjuku, Tokyo 160-8582, Japan
| | - Masato Yasui
- Department of Pharmacology, School of Medicine, Keio University, 35 Shinanomachi, Shinjuku, Tokyo 160-8582, Japan
| | - Mutsuo Nuriya
- Department of Pharmacology, School of Medicine, Keio University, 35 Shinanomachi, Shinjuku, Tokyo 160-8582, Japan.
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Abstract
Astrocytes are the predominant glial cell type in the CNS. Although astrocytes are electrically nonexcitable, their excitability is manifested by their Ca2+ signaling, which serves as a mediator of neuron-glia bidirectional interactions via tripartite synapses. Studies from in vivo two-photon imaging indicate that in healthy animals, the properties of spontaneous astrocytic Ca2+ signaling are affected by animal species, age, wakefulness and the location of astrocytes in the brain. Intercellular Ca2+ waves in astrocytes can be evoked by a variety of stimulations. In animal models of some brain disorders, astrocytes can exhibit enhanced Ca2+ excitability featured as regenerative intercellular Ca2+ waves. This review first briefly summarizes the astrocytic Ca2+ signaling pathway and the procedure of in vivo two-photon Ca2+ imaging of astrocytes. It subsequently summarizes in vivo astrocytic Ca2+ signaling in health and brain disorders from experimental studies of animal models, and discusses the possible mechanisms and therapeutic implications underlying the enhanced Ca2+ excitability in astrocytes in brain disorders. Finally, this review summarizes molecular genetic approaches used to selectively manipulate astrocyte function in vivo and their applications to study the role of astrocytes in synaptic plasticity and brain disorders.
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Affiliation(s)
- Shinghua Ding
- Dalton Cardiovascular Research Center, Department of Biological Engineering, University of Missouri, Columbia, MO 65211, USA
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