1
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Wang J, Owji AP, Kittredge A, Clark Z, Zhang Y, Yang T. GAD65 tunes the functions of Best1 as a GABA receptor and a neurotransmitter conducting channel. Nat Commun 2024; 15:8051. [PMID: 39277606 PMCID: PMC11401937 DOI: 10.1038/s41467-024-52039-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Accepted: 08/23/2024] [Indexed: 09/17/2024] Open
Abstract
Bestrophin-1 (Best1) is an anion channel genetically linked to vision-threatening retinal degenerative channelopathies. Here, we identify interactions between Best1 and both isoforms of glutamic acid decarboxylases (GAD65 and GAD67), elucidate the distinctive influences of GAD65 and GAD67 on Best1's permeability to various anions/neurotransmitters, discover the functionality of Best1 as a γ-Aminobutyric acid (GABA) type A receptor, and solve the structure of GABA-bound Best1. GAD65 and GAD67 both promote Best1-mediated Cl- currents, but only GAD65 drastically enhances the permeability of Best1 to glutamate and GABA, for which GAD67 has no effect. GABA binds to Best1 on an extracellular site and stimulates Best1-mediated Cl- currents at the nano-molar concentration level. The physiological role of GAD65 as a cell type-specific binding partner and facilitator of Best1 is demonstrated in retinal pigment epithelial cells. Together, our results reveal critical regulators of Best1 and inform a network of membrane transport metabolons formed between bestrophin channels and glutamate metabolic enzymes.
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Affiliation(s)
- Jiali Wang
- Department of Ophthalmology, Columbia University, New York, NY, USA
| | - Aaron P Owji
- Department of Ophthalmology, Columbia University, New York, NY, USA
| | - Alec Kittredge
- Department of Ophthalmology, Columbia University, New York, NY, USA
| | - Zada Clark
- Department of Ophthalmology, Columbia University, New York, NY, USA
| | - Yu Zhang
- Department of Ophthalmology, Columbia University, New York, NY, USA.
| | - Tingting Yang
- Department of Ophthalmology, Columbia University, New York, NY, USA.
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2
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Won D, Lee EH, Chang JE, Nam MH, Park KD, Oh SJ, Hwang JY. The role of astrocytic γ-aminobutyric acid in the action of inhalational anesthetics. Eur J Pharmacol 2024; 970:176494. [PMID: 38484926 DOI: 10.1016/j.ejphar.2024.176494] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Revised: 01/24/2024] [Accepted: 03/11/2024] [Indexed: 03/21/2024]
Abstract
BACKGROUND Inhalational anesthetics target the inhibitory extrasynaptic γ-aminobutyric acid type A (GABAA) receptors. Both neuronal and glial GABA mediate tonic inhibition of the extrasynaptic GABAA receptors. However, the role of glial GABA during inhalational anesthesia remains unclear. This study aimed to evaluate whether astrocytic GABA contributes to the action of different inhalational anesthetics. METHODS Gene knockout of monoamine oxidase B (MAOB) was used to reduce astrocytic GABA levels in mice. The hypnotic and immobilizing effects of isoflurane, sevoflurane, and desflurane were assessed by evaluating the loss of righting reflex (LORR) and tail-pinch withdrawal response (LTWR) in MAOB knockout and wild-type mice. Minimum alveolar concentration (MAC) for LORR, time to LORR, MAC for LTWR and time to LTWR of isoflurane, sevoflurane, and desflurane were assessed. RESULTS Time to LORR and time to LTWR with isoflurane were significantly longer in MAOB knockout mice than in wild-type mice (P < 0.001 and P = 0.032, respectively). Time to LORR with 0.8 MAC of sevoflurane was significantly longer in MAOB knockout mice than in wild-type mice (P < 0.001), but not with 1.0 MAC of sevoflurane (P=0.217). MAC for LTWR was significantly higher in MAOB knockout mice exposed to sevoflurane (P < 0.001). With desflurane, MAOB knockout mice had a significantly higher MAC for LORR (P = 0.003) and higher MAC for LTWR (P < 0.001) than wild-type mice. CONCLUSIONS MAOB knockout mice showed reduced sensitivity to the hypnotic and immobilizing effects of isoflurane, sevoflurane, and desflurane. Behavioral tests revealed that the hypnotic and immobilizing effects of inhalational anesthetics would be mediated by astrocytic GABA.
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Affiliation(s)
- Dongwook Won
- Department of Anesthesiology and Pain Medicine, SMG-SNU Boramae Medical Center, Seoul, Republic of Korea; College of Medicine, Seoul National University, Seoul, Republic of Korea
| | - Elliot H Lee
- Brain Science Institute, Korea Institute of Science and Technology, Seoul, Republic of Korea
| | - Jee-Eun Chang
- Department of Anesthesiology and Pain Medicine, SMG-SNU Boramae Medical Center, Seoul, Republic of Korea; College of Medicine, Seoul National University, Seoul, Republic of Korea
| | - Min-Ho Nam
- Brain Science Institute, Korea Institute of Science and Technology, Seoul, Republic of Korea
| | - Ki Duk Park
- Brain Science Institute, Korea Institute of Science and Technology, Seoul, Republic of Korea
| | - Soo-Jin Oh
- Brain Science Institute, Korea Institute of Science and Technology, Seoul, Republic of Korea.
| | - Jin-Young Hwang
- Department of Anesthesiology and Pain Medicine, SMG-SNU Boramae Medical Center, Seoul, Republic of Korea; College of Medicine, Seoul National University, Seoul, Republic of Korea.
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3
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Ju YH, Cho J, Park JY, Kim H, Hong EB, Park KD, Lee CJ, Chung E, Kim HI, Nam MH. Tonic excitation by astrocytic GABA causes neuropathic pain by augmenting neuronal activity and glucose metabolism. Exp Mol Med 2024; 56:1193-1205. [PMID: 38760512 PMCID: PMC11148027 DOI: 10.1038/s12276-024-01232-z] [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: 11/18/2023] [Revised: 02/21/2024] [Accepted: 02/29/2024] [Indexed: 05/19/2024] Open
Abstract
Neuropathic pain is a debilitating condition caused by the hyperexcitability of spinal dorsal horn neurons and is often characterized by allodynia. Although neuron-independent mechanisms of hyperexcitability have been investigated, the contribution of astrocyte-neuron interactions remains unclear. Here, we show evidence of reactive astrocytes and their excessive GABA release in the spinal dorsal horn, which paradoxically leads to the tonic excitation of neighboring neurons in a neuropathic pain model. Using multiple electrophysiological methods, we demonstrated that neuronal hyperexcitability is attributed to both increased astrocytic GABA synthesis via monoamine oxidase B (MAOB) and the depolarized reversal potential of GABA-mediated currents (EGABA) via the downregulation of the neuronal K+/Cl- cotransporter KCC2. Furthermore, longitudinal 2-deoxy-2-[18F]-fluoro-D-glucose microPET imaging demonstrated increased regional glucose metabolism in the ipsilateral dorsal horn, reflecting neuronal hyperexcitability. Importantly, inhibiting MAOB restored the entire astrocytic GABA-mediated cascade and abrogated the increased glucose metabolism and mechanical allodynia. Overall, astrocytic GABA-mediated tonic excitation is critical for neuronal hyperexcitability, leading to mechanical allodynia and neuropathic pain.
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Affiliation(s)
- Yeon Ha Ju
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea
| | - Jongwook Cho
- Department of Biomedical Science and Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju, 61005, Republic of Korea
| | - Ji-Young Park
- Department of Biomedical Science and Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju, 61005, Republic of Korea
| | - Hyunjin Kim
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea
| | - Eun-Bin Hong
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea
| | - Ki Duk Park
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea
| | - C Justin Lee
- Center for Cognition and Sociality, Institute for Basic Science, Daejeon, 34126, Republic of Korea
| | - Euiheon Chung
- Department of Biomedical Science and Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju, 61005, Republic of Korea
| | - Hyoung-Ihl Kim
- Department of Biomedical Science and Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju, 61005, Republic of Korea.
- Department of Neurosurgery, Presbyterian Medical Center, Jeonju, 54987, Republic of Korea.
| | - Min-Ho Nam
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea.
- Department of KHU-KIST Convergence Science and Technology, Kyung Hee University, Seoul, 02447, Republic of Korea.
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4
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Lia A, Di Spiezio A, Vitalini L, Tore M, Puja G, Losi G. Ion Channels and Ionotropic Receptors in Astrocytes: Physiological Functions and Alterations in Alzheimer's Disease and Glioblastoma. Life (Basel) 2023; 13:2038. [PMID: 37895420 PMCID: PMC10608464 DOI: 10.3390/life13102038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2023] [Revised: 10/03/2023] [Accepted: 10/07/2023] [Indexed: 10/29/2023] Open
Abstract
The human brain is composed of nearly one hundred billion neurons and an equal number of glial cells, including macroglia, i.e., astrocytes and oligodendrocytes, and microglia, the resident immune cells of the brain. In the last few decades, compelling evidence has revealed that glial cells are far more active and complex than previously thought. In particular, astrocytes, the most abundant glial cell population, not only take part in brain development, metabolism, and defense against pathogens and insults, but they also affect sensory, motor, and cognitive functions by constantly modulating synaptic activity. Not surprisingly, astrocytes are actively involved in neurodegenerative diseases (NDs) and other neurological disorders like brain tumors, in which they rapidly become reactive and mediate neuroinflammation. Reactive astrocytes acquire or lose specific functions that differently modulate disease progression and symptoms, including cognitive impairments. Astrocytes express several types of ion channels, including K+, Na+, and Ca2+ channels, transient receptor potential channels (TRP), aquaporins, mechanoreceptors, and anion channels, whose properties and functions are only partially understood, particularly in small processes that contact synapses. In addition, astrocytes express ionotropic receptors for several neurotransmitters. Here, we provide an extensive and up-to-date review of the roles of ion channels and ionotropic receptors in astrocyte physiology and pathology. As examples of two different brain pathologies, we focus on Alzheimer's disease (AD), one of the most diffuse neurodegenerative disorders, and glioblastoma (GBM), the most common brain tumor. Understanding how ion channels and ionotropic receptors in astrocytes participate in NDs and tumors is necessary for developing new therapeutic tools for these increasingly common neurological conditions.
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Affiliation(s)
- Annamaria Lia
- Department Biomedical Science, University of Padova, 35131 Padova, Italy; (A.L.); (A.D.S.)
| | - Alessandro Di Spiezio
- Department Biomedical Science, University of Padova, 35131 Padova, Italy; (A.L.); (A.D.S.)
- Neuroscience Institute (CNR-IN), Padova Section, 35131 Padova, Italy
| | - Lorenzo Vitalini
- Department Life Science, University of Modena and Reggio Emilia, 41125 Modena, Italy; (L.V.); (G.P.)
| | - Manuela Tore
- Institute of Nanoscience (CNR-NANO), Modena Section, 41125 Modena, Italy;
- Department Biomedical Science, Metabolic and Neuroscience, University of Modena and Reggio Emilia, 41125 Modena, Italy
| | - Giulia Puja
- Department Life Science, University of Modena and Reggio Emilia, 41125 Modena, Italy; (L.V.); (G.P.)
| | - Gabriele Losi
- Institute of Nanoscience (CNR-NANO), Modena Section, 41125 Modena, Italy;
- Department Biomedical Science, Metabolic and Neuroscience, University of Modena and Reggio Emilia, 41125 Modena, Italy
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5
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Koh W, Kwak H, Cheong E, Lee CJ. GABA tone regulation and its cognitive functions in the brain. Nat Rev Neurosci 2023; 24:523-539. [PMID: 37495761 DOI: 10.1038/s41583-023-00724-7] [Citation(s) in RCA: 27] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/26/2023] [Indexed: 07/28/2023]
Abstract
γ-Aminobutyric acid (GABA) is the major inhibitory neurotransmitter released at GABAergic synapses, mediating fast-acting phasic inhibition. Emerging lines of evidence unequivocally indicate that a small amount of extracellular GABA - GABA tone - exists in the brain and induces a tonic GABA current that controls neuronal activity on a slow timescale relative to that of phasic inhibition. Surprisingly, studies indicate that glial cells that synthesize GABA, such as astrocytes, release GABA through non-vesicular mechanisms, such as channel-mediated release, and thereby act as the source of GABA tone in the brain. In this Review, we first provide an overview of major advances in our understanding of the cell-specific molecular and cellular mechanisms of GABA synthesis, release and clearance that regulate GABA tone in various brain regions. We next examine the diverse ways in which the tonic GABA current regulates synaptic transmission and synaptic plasticity through extrasynaptic GABAA-receptor-mediated mechanisms. Last, we discuss the physiological mechanisms through which tonic inhibition modulates cognitive function on a slow timescale. In this Review, we emphasize that the cognitive functions of tonic GABA current extend beyond mere inhibition, laying a foundation for future research on the physiological and pathophysiological roles of GABA tone regulation in normal and abnormal psychiatric conditions.
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Affiliation(s)
- Wuhyun Koh
- Center for Cognition and Sociality, Institute for Basic Science, Daejeon, South Korea
| | - Hankyul Kwak
- Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University, Seoul, South Korea
| | - Eunji Cheong
- Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University, Seoul, South Korea.
| | - C Justin Lee
- Center for Cognition and Sociality, Institute for Basic Science, Daejeon, South Korea.
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6
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Wang LY, Wang XP, Lv JM, Shan YD, Jia SY, Yu ZF, Miao HT, Xin Y, Zhang DX, Zhang LM. NLRP3-GABA signaling pathway contributes to the pathogenesis of impulsive-like behaviors and cognitive deficits in aged mice. J Neuroinflammation 2023; 20:162. [PMID: 37434240 DOI: 10.1186/s12974-023-02845-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Accepted: 07/02/2023] [Indexed: 07/13/2023] Open
Abstract
BACKGROUND Perioperative neurocognitive disorders (PND), such as delirium and cognitive impairment, are commonly encountered complications in aged patients. The inhibitory neurotransmitter γ-aminobutyric acid (GABA) is aberrantly synthesized from reactive astrocytes following inflammatory stimulation and is implicated in the pathophysiology of neurodegenerative diseases. Additionally, the activation of NOD-like receptor protein 3 (NLRP3) inflammasome is involved in PND. Herein, we aimed to investigate whether the NLRP3-GABA signaling pathway contributes to the pathogenesis of aging mice's PND. METHODS 24-month-old C57BL/6 and astrocyte-specific NLRP3 knockout male mice were used to establish a PND model via tibial fracture surgery. The monoamine oxidase-B (MAOB) inhibitor selegiline (1 mg/kg) was intraperitoneally administered once a day for 7 days after the surgery. PND, including impulsive-like behaviors and cognitive impairment, was evaluated by open field test, elevated plus maze, and fear conditioning. Thereafter, pathological changes of neurodegeneration were explored by western blot and immunofluorescence assays. RESULTS Selegiline administration significantly ameliorated TF-induced impulsive-like behaviors and reduced excessive GABA production in reactive hippocampal astrocytes. Moreover, astrocyte-specific NLRP3 knockout mice reversed TF-induced impulsive-like and cognitive impairment behaviors, decreased GABA levels in reactive astrocytes, ameliorated NLRP3-associated inflammatory responses during the early stage, and restored neuronal degeneration in the hippocampus. CONCLUSIONS Our findings suggest that anesthesia and surgical procedures trigger neuroinflammation and cognitive deficits, which may be due to NLRP3-GABA activation in the hippocampus of aged mice.
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Affiliation(s)
- Lu-Ying Wang
- Department of Anesthesia and Trauma Research, Department of Anesthesiology, Hebei Province Cangzhou Hospital of Integrated Traditional and Western Medicine, Cangzhou, China
| | - Xu-Peng Wang
- Department of Anesthesiology, Third Hospital of Hebei Medical University, Shijiazhuang, Hebei, China
| | - Jin-Meng Lv
- Department of Anesthesia and Trauma Research, Department of Anesthesiology, Hebei Province Cangzhou Hospital of Integrated Traditional and Western Medicine, Cangzhou, China
| | - Yu-Dong Shan
- Department of Anesthesia and Trauma Research, Department of Anesthesiology, Hebei Province Cangzhou Hospital of Integrated Traditional and Western Medicine, Cangzhou, China
| | - Shi-Yan Jia
- Department of Anesthesia and Trauma Research, Department of Anesthesiology, Hebei Province Cangzhou Hospital of Integrated Traditional and Western Medicine, Cangzhou, China
| | - Zhi-Fang Yu
- Department of Anesthesia and Trauma Research, Department of Anesthesiology, Hebei Province Cangzhou Hospital of Integrated Traditional and Western Medicine, Cangzhou, China
| | - Hui-Tao Miao
- Department of Anesthesiology, Hebei Province Cangzhou Hospital of Integrated Traditional and Western Medicine, Cangzhou, China
| | - Yue Xin
- Department of Anesthesiology, Hebei Province Cangzhou Hospital of Integrated Traditional and Western Medicine, Cangzhou, China
| | - Dong-Xue Zhang
- Department of Gerontology, Cangzhou Central Hospital, Cangzhou, China
| | - Li-Min Zhang
- Department of Anesthesiology, Hebei Province Cangzhou Hospital of Integrated Traditional and Western Medicine, Cangzhou, China.
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7
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Purushotham SS, Buskila Y. Astrocytic modulation of neuronal signalling. FRONTIERS IN NETWORK PHYSIOLOGY 2023; 3:1205544. [PMID: 37332623 PMCID: PMC10269688 DOI: 10.3389/fnetp.2023.1205544] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Accepted: 05/18/2023] [Indexed: 06/20/2023]
Abstract
Neuronal signalling is a key element in neuronal communication and is essential for the proper functioning of the CNS. Astrocytes, the most prominent glia in the brain play a key role in modulating neuronal signalling at the molecular, synaptic, cellular, and network levels. Over the past few decades, our knowledge about astrocytes and their functioning has evolved from considering them as merely a brain glue that provides structural support to neurons, to key communication elements. Astrocytes can regulate the activity of neurons by controlling the concentrations of ions and neurotransmitters in the extracellular milieu, as well as releasing chemicals and gliotransmitters that modulate neuronal activity. The aim of this review is to summarise the main processes through which astrocytes are modulating brain function. We will systematically distinguish between direct and indirect pathways in which astrocytes affect neuronal signalling at all levels. Lastly, we will summarize pathological conditions that arise once these signalling pathways are impaired focusing on neurodegeneration.
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Affiliation(s)
| | - Yossi Buskila
- School of Medicine, Western Sydney University, Campbelltown, NSW, Australia
- The MARCS Institute, Western Sydney University, Campbelltown, NSW, Australia
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8
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Tang Y, Yan Y, Mao J, Ni J, Qing H. The hippocampus associated GABAergic neural network impairment in early-stage of Alzheimer's disease. Ageing Res Rev 2023; 86:101865. [PMID: 36716975 DOI: 10.1016/j.arr.2023.101865] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Revised: 01/13/2023] [Accepted: 01/25/2023] [Indexed: 01/29/2023]
Abstract
Alzheimer's disease (AD) is the commonest neurodegenerative disease with slow progression. Pieces of evidence suggest that the GABAergic system is impaired in the early stage of AD, leading to hippocampal neuron over-activity and further leading to memory and cognitive impairment in patients with AD. However, the precise impairment mechanism of the GABAergic system on the pathogenesis of AD is still unclear. The impairment of neural networks associated with the GABAergic system is tightly associated with AD. Therefore, we describe the roles played by hippocampus-related GABAergic circuits and their impairments in AD neuropathology. In addition, we give our understand on the process from GABAergic circuit impairment to cognitive and memory impairment, since recent studies on astrocyte in AD plays an important role behind cognition dysfunction caused by GABAergic circuit impairment, which helps better understand the GABAergic system and could open up innovative AD therapy.
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Affiliation(s)
- Yuanhong Tang
- Key Laboratory of Molecular Medicine and Biotherapy, School of Life Science, Beijing Institute of Technology, Beijing 100081, China
| | - Yan Yan
- Key Laboratory of Molecular Medicine and Biotherapy, School of Life Science, Beijing Institute of Technology, Beijing 100081, China
| | - Jian Mao
- Zhengzhou Tobacco Institute of China National Tobacco Company, Zhengzhou 450001, China
| | - Junjun Ni
- Key Laboratory of Molecular Medicine and Biotherapy, School of Life Science, Beijing Institute of Technology, Beijing 100081, China.
| | - Hong Qing
- Key Laboratory of Molecular Medicine and Biotherapy, School of Life Science, Beijing Institute of Technology, Beijing 100081, China; Department of Biology, Shenzhen MSU-BIT University, Shenzhen 518172, China.
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9
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Kilb W, Kirischuk S. GABA Release from Astrocytes in Health and Disease. Int J Mol Sci 2022; 23:ijms232415859. [PMID: 36555501 PMCID: PMC9784789 DOI: 10.3390/ijms232415859] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Revised: 12/06/2022] [Accepted: 12/10/2022] [Indexed: 12/15/2022] Open
Abstract
Astrocytes are the most abundant glial cells in the central nervous system (CNS) mediating a variety of homeostatic functions, such as spatial K+ buffering or neurotransmitter reuptake. In addition, astrocytes are capable of releasing several biologically active substances, including glutamate and GABA. Astrocyte-mediated GABA release has been a matter of debate because the expression level of the main GABA synthesizing enzyme glutamate decarboxylase is quite low in astrocytes, suggesting that low intracellular GABA concentration ([GABA]i) might be insufficient to support a non-vesicular GABA release. However, recent studies demonstrated that, at least in some regions of the CNS, [GABA]i in astrocytes might reach several millimoles both under physiological and especially pathophysiological conditions, thereby enabling GABA release from astrocytes via GABA-permeable anion channels and/or via GABA transporters operating in reverse mode. In this review, we summarize experimental data supporting both forms of GABA release from astrocytes in health and disease, paying special attention to possible feedback mechanisms that might govern the fine-tuning of astrocytic GABA release and, in turn, the tonic GABAA receptor-mediated inhibition in the CNS.
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10
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Kovács Z, Skatchkov SN, Szabó Z, Qahtan S, Méndez-González MP, Malpica-Nieves CJ, Eaton MJ, Kardos J, Héja L. Putrescine Intensifies Glu/GABA Exchange Mechanism and Promotes Early Termination of Seizures. Int J Mol Sci 2022; 23:ijms23158191. [PMID: 35897767 PMCID: PMC9331600 DOI: 10.3390/ijms23158191] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Revised: 06/30/2022] [Accepted: 07/21/2022] [Indexed: 02/01/2023] Open
Abstract
Endogenous anticonvulsant mechanisms represent a reliable and currently underdeveloped strategy against recurrent seizures and may recall novel original therapeutics. Here, we investigated whether the intensification of the astroglial Glu-GABA exchange mechanism by application of the GABA precursor putrescine (PUT) may be effective against convulsive and non-convulsive seizures. We explored the potential of PUT to inhibit spontaneous spike-and-wave discharges (SWDs) in WAG/Rij rats, a genetic model of absence epilepsy. Significant shortening of SWDs in response to intraperitoneally applied PUT has been observed, which could be antagonized by blocking GAT-2/3-mediated astrocytic GABA release with the specific inhibitor SNAP-5114. Direct application of exogenous GABA also reduced SWD duration, suggesting that PUT-triggered astroglial GABA release through GAT-2/3 may be a critical step in limiting seizure duration. PUT application also dose-dependently shortened seizure-like events (SLEs) in the low-[Mg2+] in vitro model of temporal lobe epilepsy. SNAP-5114 reversed the antiepileptic effect of PUT in the in vitro model as well, further confirming that PUT reduces seizure duration by triggering glial GABA release. In accordance, we observed that PUT specifically reduces the frequency of excitatory synaptic potentials, suggesting that it specifically acts at excitatory synapses. We also identified that PUT specifically eliminated the tonic depolarization-induced desynchronization of SLEs. Since PUT is an important source of glial GABA and we previously showed significant GABA release, it is suggested that the astroglial Glu-GABA exchange mechanism plays a key role in limiting ictal discharges, potentially opening up novel pathways to control seizure propagation and generalization.
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Affiliation(s)
- Zsolt Kovács
- Department of Biology, Savaria University Centre, ELTE Eötvös Loránd University, Károlyi Gáspár tér 4, 9700 Szombathely, Hungary;
| | - Serguei N. Skatchkov
- Department of Physiology, Universidad Central del Caribe, Bayamon, PR 00960, USA; (S.N.S.); (C.J.M.-N.)
- Department of Biochemistry, Universidad Central del Caribe, Bayamon, PR 00960, USA; (M.P.M.-G.); (M.J.E.)
| | - Zsolt Szabó
- Functional Pharmacology Research Group, Institute of Organic Chemistry, Research Centre for Natural Sciences, Magyar Tudósok Körútja 2, 1117 Budapest, Hungary; (Z.S.); (S.Q.); (J.K.)
| | - Saif Qahtan
- Functional Pharmacology Research Group, Institute of Organic Chemistry, Research Centre for Natural Sciences, Magyar Tudósok Körútja 2, 1117 Budapest, Hungary; (Z.S.); (S.Q.); (J.K.)
- Hevesy György PhD School of Chemistry, ELTE Eötvös Loránd University, Pázmány Péter sétány 1/A, 1117 Budapest, Hungary
- College of Science, University of Al-Qadisiyah, Al-Diwaniyah 58001, Iraq
| | - Miguel P. Méndez-González
- Department of Biochemistry, Universidad Central del Caribe, Bayamon, PR 00960, USA; (M.P.M.-G.); (M.J.E.)
- Natural Sciences Department, University of Puerto Rico in Aguadilla, Aguadilla, PR 00604, USA
- Department of Science and Technology, Antilles Adventist University, Mayagüez, PR 00681, USA
| | - Christian J. Malpica-Nieves
- Department of Physiology, Universidad Central del Caribe, Bayamon, PR 00960, USA; (S.N.S.); (C.J.M.-N.)
- Department of Biochemistry, Universidad Central del Caribe, Bayamon, PR 00960, USA; (M.P.M.-G.); (M.J.E.)
| | - Misty J. Eaton
- Department of Biochemistry, Universidad Central del Caribe, Bayamon, PR 00960, USA; (M.P.M.-G.); (M.J.E.)
| | - Julianna Kardos
- Functional Pharmacology Research Group, Institute of Organic Chemistry, Research Centre for Natural Sciences, Magyar Tudósok Körútja 2, 1117 Budapest, Hungary; (Z.S.); (S.Q.); (J.K.)
| | - László Héja
- Functional Pharmacology Research Group, Institute of Organic Chemistry, Research Centre for Natural Sciences, Magyar Tudósok Körútja 2, 1117 Budapest, Hungary; (Z.S.); (S.Q.); (J.K.)
- Correspondence:
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11
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Nam MH, Sa M, Ju YH, Park MG, Lee CJ. Revisiting the Role of Astrocytic MAOB in Parkinson's Disease. Int J Mol Sci 2022; 23:4453. [PMID: 35457272 PMCID: PMC9028367 DOI: 10.3390/ijms23084453] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Revised: 04/13/2022] [Accepted: 04/16/2022] [Indexed: 12/11/2022] Open
Abstract
Monoamine oxidase-B (MAOB) has been believed to mediate the degradation of monoamine neurotransmitters such as dopamine. However, this traditional belief has been challenged by demonstrating that it is not MAOB but MAOA which mediates dopamine degradation. Instead, MAOB mediates the aberrant synthesis of GABA and hydrogen peroxide (H2O2) in reactive astrocytes of Parkinson's disease (PD). Astrocytic GABA tonically suppresses the dopaminergic neuronal activity, whereas H2O2 aggravates astrocytic reactivity and dopaminergic neuronal death. Recently discovered reversible MAOB inhibitors reduce reactive astrogliosis and restore dopaminergic neuronal activity to alleviate PD symptoms in rodents. In this perspective, we redefine the role of MAOB for the aberrant suppression and deterioration of dopaminergic neurons through excessive GABA and H2O2 synthesis of reactive astrocytes in PD.
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Affiliation(s)
- Min-Ho Nam
- Brain Science Institute, Korea Institute of Science and Technology, Seoul 02792, Korea;
- Department of KHU-KIST Convergence Science and Technology, Kyung Hee University, Seoul 02453, Korea
| | - Moonsun Sa
- KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul 02841, Korea; (M.S.); (M.G.P.)
- Center for Cognition and Sociality, Institute for Basic Science, Daejeon 34126, Korea
| | - Yeon Ha Ju
- Brain Science Institute, Korea Institute of Science and Technology, Seoul 02792, Korea;
| | - Mingu Gordon Park
- KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul 02841, Korea; (M.S.); (M.G.P.)
- Center for Cognition and Sociality, Institute for Basic Science, Daejeon 34126, Korea
| | - C. Justin Lee
- KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul 02841, Korea; (M.S.); (M.G.P.)
- Center for Cognition and Sociality, Institute for Basic Science, Daejeon 34126, Korea
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12
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Honoré E, Khlaifia A, Bosson A, Lacaille JC. Hippocampal Somatostatin Interneurons, Long-Term Synaptic Plasticity and Memory. Front Neural Circuits 2021; 15:687558. [PMID: 34149368 PMCID: PMC8206813 DOI: 10.3389/fncir.2021.687558] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Accepted: 04/30/2021] [Indexed: 12/13/2022] Open
Abstract
A distinctive feature of the hippocampal structure is the diversity of inhibitory interneurons. These complex inhibitory interconnections largely contribute to the tight modulation of hippocampal circuitry, as well as to the formation and coordination of neuronal assemblies underlying learning and memory. Inhibitory interneurons provide more than a simple transitory inhibition of hippocampal principal cells (PCs). The synaptic plasticity of inhibitory neurons provides long-lasting changes in the hippocampal network and is a key component of memory formation. The dendrite targeting interneurons expressing the peptide somatostatin (SOM) are particularly interesting in this regard because they display unique long-lasting synaptic changes leading to metaplastic regulation of hippocampal networks. In this article, we examine the actions of the neuropeptide SOM on hippocampal cells, synaptic plasticity, learning, and memory. We address the different subtypes of hippocampal SOM interneurons. We describe the long-term synaptic plasticity that takes place at the excitatory synapses of SOM interneurons, its singular induction and expression mechanisms, as well as the consequences of these changes on the hippocampal network, learning, and memory. We also review evidence that astrocytes provide cell-specific dynamic regulation of inhibition of PC dendrites by SOM interneurons. Finally, we cover how, in mouse models of Alzheimer’s disease (AD), dysfunction of plasticity of SOM interneuron excitatory synapses may also contribute to cognitive impairments in brain disorders.
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Affiliation(s)
- Eve Honoré
- Department of Neurosciences, Centre for Interdisciplinary Research on Brain and Learning, Research Group on the Central Nervous System, Université de Montréal, Montreal, QC, Canada
| | - Abdessattar Khlaifia
- Department of Neurosciences, Centre for Interdisciplinary Research on Brain and Learning, Research Group on the Central Nervous System, Université de Montréal, Montreal, QC, Canada
| | - Anthony Bosson
- Department of Neurosciences, Centre for Interdisciplinary Research on Brain and Learning, Research Group on the Central Nervous System, Université de Montréal, Montreal, QC, Canada
| | - Jean-Claude Lacaille
- Department of Neurosciences, Centre for Interdisciplinary Research on Brain and Learning, Research Group on the Central Nervous System, Université de Montréal, Montreal, QC, Canada
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13
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Szabó Z, Péter M, Héja L, Kardos J. Dual Role for Astroglial Copper-Assisted Polyamine Metabolism during Intense Network Activity. Biomolecules 2021; 11:604. [PMID: 33921742 PMCID: PMC8073386 DOI: 10.3390/biom11040604] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Revised: 04/09/2021] [Accepted: 04/14/2021] [Indexed: 12/29/2022] Open
Abstract
Astrocytes serve essential roles in human brain function and diseases. Growing evidence indicates that astrocytes are central players of the feedback modulation of excitatory Glu signalling during epileptiform activity via Glu-GABA exchange. The underlying mechanism results in the increase of tonic inhibition by reverse operation of the astroglial GABA transporter, induced by Glu-Na+ symport. GABA, released from astrocytes, is synthesized from the polyamine (PA) putrescine and this process involves copper amino oxidase. Through this pathway, putrescine can be considered as an important source of inhibitory signaling that counterbalances epileptic discharges. Putrescine, however, is also a precursor for spermine that is known to enhance gap junction channel communication and, consequently, supports long-range Ca2+ signaling and contributes to spreading of excitatory activity through the astrocytic syncytium. Recently, we presented the possibility of neuron-glia redox coupling through copper (Cu+/Cu2+) signaling and oxidative putrescine catabolism. In the current work, we explore whether the Cu+/Cu2+ homeostasis is involved in astrocytic control on neuronal excitability by regulating PA catabolism. We provide supporting experimental data underlying this hypothesis. We show that the blockade of copper transporter (CTR1) by AgNO3 (3.6 µM) prevents GABA transporter-mediated tonic inhibitory currents, indicating causal relationship between copper (Cu+/Cu2+) uptake and the catabolism of putrescine to GABA in astrocytes. In addition, we show that MnCl2 (20 μM), an inhibitor of the divalent metal transporter DMT1, also prevents the astrocytic Glu-GABA exchange. Furthermore, we observed that facilitation of copper uptake by added CuCl2 (2 µM) boosts tonic inhibitory currents. These findings corroborate the hypothesis that modulation of neuron-glia coupling by copper uptake drives putrescine → GABA transformation, which leads to subsequent Glu-GABA exchange and tonic inhibition. Findings may in turn highlight the potential role of copper signaling in fine-tuning the activity of the tripartite synapse.
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Affiliation(s)
- Zsolt Szabó
- Functional Pharmacology Research Group, Research Centre for Natural Sciences, Institute of Organic Chemistry, H-1117 Budapest, Hungary; (Z.S.); (M.P.); (J.K.)
| | - Márton Péter
- Functional Pharmacology Research Group, Research Centre for Natural Sciences, Institute of Organic Chemistry, H-1117 Budapest, Hungary; (Z.S.); (M.P.); (J.K.)
- Hevesy György Ph.D. School of Chemistry, ELTE Eötvös Loránd University, H-1117 Budapest, Hungary
| | - László Héja
- Functional Pharmacology Research Group, Research Centre for Natural Sciences, Institute of Organic Chemistry, H-1117 Budapest, Hungary; (Z.S.); (M.P.); (J.K.)
| | - Julianna Kardos
- Functional Pharmacology Research Group, Research Centre for Natural Sciences, Institute of Organic Chemistry, H-1117 Budapest, Hungary; (Z.S.); (M.P.); (J.K.)
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14
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Sharma S, Tiarks G, Haight J, Bassuk AG. Neuropathophysiological Mechanisms and Treatment Strategies for Post-traumatic Epilepsy. Front Mol Neurosci 2021; 14:612073. [PMID: 33708071 PMCID: PMC7940684 DOI: 10.3389/fnmol.2021.612073] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Accepted: 01/26/2021] [Indexed: 12/11/2022] Open
Abstract
Traumatic brain injury (TBI) is a leading cause of death in young adults and a risk factor for acquired epilepsy. Severe TBI, after a period of time, causes numerous neuropsychiatric and neurodegenerative problems with varying comorbidities; and brain homeostasis may never be restored. As a consequence of disrupted equilibrium, neuropathological changes such as circuit remodeling, reorganization of neural networks, changes in structural and functional plasticity, predisposition to synchronized activity, and post-translational modification of synaptic proteins may begin to dominate the brain. These pathological changes, over the course of time, contribute to conditions like Alzheimer disease, dementia, anxiety disorders, and post-traumatic epilepsy (PTE). PTE is one of the most common, devastating complications of TBI; and of those affected by a severe TBI, more than 50% develop PTE. The etiopathology and mechanisms of PTE are either unknown or poorly understood, which makes treatment challenging. Although anti-epileptic drugs (AEDs) are used as preventive strategies to manage TBI, control acute seizures and prevent development of PTE, their efficacy in PTE remains controversial. In this review, we discuss novel mechanisms and risk factors underlying PTE. We also discuss dysfunctions of neurovascular unit, cell-specific neuroinflammatory mediators and immune response factors that are vital for epileptogenesis after TBI. Finally, we describe current and novel treatments and management strategies for preventing PTE.
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Affiliation(s)
- Shaunik Sharma
- Medical Laboratories, Department of Pediatrics, University of Iowa, Iowa City, IA, United States
| | - Grant Tiarks
- Medical Laboratories, Department of Pediatrics, University of Iowa, Iowa City, IA, United States
| | - Joseph Haight
- Medical Laboratories, Department of Pediatrics, University of Iowa, Iowa City, IA, United States
| | - Alexander G Bassuk
- Medical Laboratories, Department of Pediatrics, University of Iowa, Iowa City, IA, United States
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15
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Fernandez-Abascal J, Graziano B, Encalada N, Bianchi L. Glial Chloride Channels in the Function of the Nervous System Across Species. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021; 1349:195-223. [PMID: 35138616 PMCID: PMC11247392 DOI: 10.1007/978-981-16-4254-8_10] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
In the nervous system, the concentration of Cl- in neurons that express GABA receptors plays a key role in establishing whether these neurons are excitatory, mostly during early development, or inhibitory. Thus, much attention has been dedicated to understanding how neurons regulate their intracellular Cl- concentration. However, regulation of the extracellular Cl- concentration by other cells of the nervous system, including glia and microglia, is as important because it ultimately affects the Cl- equilibrium potential across the neuronal plasma membrane. Moreover, Cl- ions are transported in and out of the cell, via either passive or active transporter systems, as counter ions for K+ whose concentration in the extracellular environment of the nervous system is tightly regulated because it directly affects neuronal excitability. In this book chapter, we report on the Cl- channel types expressed in the various types of glial cells focusing on the role they play in the function of the nervous system in health and disease. Furthermore, we describe the types of stimuli that these channels are activated by, the other solutes that they may transport, and the involvement of these channels in processes such as pH regulation and Regulatory Volume Decrease (RVD). The picture that emerges is one of the glial cells expressing a variety of Cl- channels, encoded by members of different gene families, involved both in short- and long-term regulation of the nervous system function. Finally, we report data on invertebrate model organisms, such as C. elegans and Drosophila, that are revealing important and previously unsuspected functions of some of these channels in the context of living and behaving animals.
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Affiliation(s)
- Jesus Fernandez-Abascal
- Department Physiology and Biophysics, University of Miami, Miller School of Medicine, Miami, FL, USA
| | - Bianca Graziano
- Department Physiology and Biophysics, University of Miami, Miller School of Medicine, Miami, FL, USA
| | - Nicole Encalada
- Department Physiology and Biophysics, University of Miami, Miller School of Medicine, Miami, FL, USA
| | - Laura Bianchi
- Department Physiology and Biophysics, University of Miami, Miller School of Medicine, Miami, FL, USA.
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16
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Wasan H, Singh D, Kh R. Safinamide in neurological disorders and beyond: Evidence from preclinical and clinical studies. Brain Res Bull 2020; 168:165-177. [PMID: 33387637 DOI: 10.1016/j.brainresbull.2020.12.018] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Revised: 12/04/2020] [Accepted: 12/27/2020] [Indexed: 01/08/2023]
Abstract
The discovery and development of safinamide, an alpha-aminoamide, has been a valuable addition to the existing clinical management of Parkinson's disease (PD). The journey of safinamide dates back to the year 1983, when an alpha-aminoamide called milacemide showed a weak anticonvulsant activity. Milacemide was then structurally modified to give rise to safinamide, which in turn produced robust anticonvulsant activity. The underlying mechanism behind this action of safinamide is attributed to the inhibition of voltage gated calcium and sodium channels. Moreover, owing to the importance of ion channels in maintaining neuronal circuitry and neurotransmitter release, numerous studies explored the potential of safinamide in neurological diseases including PD, stroke, multiple sclerosis and neuromuscular disorders such as Duchenne muscular dystrophy and non-dystrophic myotonias. Nevertheless, evidence from multiple preclinical studies suggested a potent, selective and reversible inhibitory activity of safinamide against monoamine oxidase (MAO)-B enzyme which is responsible for degrading dopamine, a neurotransmitter primarily implicated in the pathophysiology of PD. Therefore, clinical studies were conducted to assess safety and efficacy of safinamide in PD. Indeed, results from various Phase 3 clinical trials suggested strong evidence of safinamide as an add-on therapy in controlling the exacerbation of PD. This review presents a thorough developmental history of safinamide in PD and provides comprehensive insight into plausible mechanisms via which safinamide can be explored in other neurological and muscular diseases.
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Affiliation(s)
- Himika Wasan
- Department of Pharmacology, All India Institute of Medical Sciences, New Delhi, India.
| | - Devendra Singh
- Department of Pharmacology, All India Institute of Medical Sciences, New Delhi, India.
| | - Reeta Kh
- Department of Pharmacology, All India Institute of Medical Sciences, New Delhi, India.
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17
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Caudal LC, Gobbo D, Scheller A, Kirchhoff F. The Paradox of Astroglial Ca 2 + Signals at the Interface of Excitation and Inhibition. Front Cell Neurosci 2020; 14:609947. [PMID: 33324169 PMCID: PMC7726216 DOI: 10.3389/fncel.2020.609947] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Accepted: 11/03/2020] [Indexed: 12/15/2022] Open
Abstract
Astroglial networks constitute a non-neuronal communication system in the brain and are acknowledged modulators of synaptic plasticity. A sophisticated set of transmitter receptors in combination with distinct secretion mechanisms enables astrocytes to sense and modulate synaptic transmission. This integrative function evolved around intracellular Ca2+ signals, by and large considered as the main indicator of astrocyte activity. Regular brain physiology meticulously relies on the constant reciprocity of excitation and inhibition (E/I). Astrocytes are metabolically, physically, and functionally associated to the E/I convergence. Metabolically, astrocytes provide glutamine, the precursor of both major neurotransmitters governing E/I in the central nervous system (CNS): glutamate and γ-aminobutyric acid (GABA). Perisynaptic astroglial processes are structurally and functionally associated with the respective circuits throughout the CNS. Astonishingly, in astrocytes, glutamatergic as well as GABAergic inputs elicit similar rises in intracellular Ca2+ that in turn can trigger the release of glutamate and GABA as well. Paradoxically, as gliotransmitters, these two molecules can thus strengthen, weaken or even reverse the input signal. Therefore, the net impact on neuronal network function is often convoluted and cannot be simply predicted by the nature of the stimulus itself. In this review, we highlight the ambiguity of astrocytes on discriminating and affecting synaptic activity in physiological and pathological state. Indeed, aberrant astroglial Ca2+ signaling is a key aspect of pathological conditions exhibiting compromised network excitability, such as epilepsy. Here, we gather recent evidence on the complexity of astroglial Ca2+ signals in health and disease, challenging the traditional, neuro-centric concept of segregating E/I, in favor of a non-binary, mutually dependent perspective on glutamatergic and GABAergic transmission.
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Affiliation(s)
- Laura C Caudal
- Department of Molecular Physiology, Center for Integrative Physiology and Molecular Medicine, University of Saarland, Homburg, Germany
| | - Davide Gobbo
- Department of Molecular Physiology, Center for Integrative Physiology and Molecular Medicine, University of Saarland, Homburg, Germany
| | - Anja Scheller
- Department of Molecular Physiology, Center for Integrative Physiology and Molecular Medicine, University of Saarland, Homburg, Germany
| | - Frank Kirchhoff
- Department of Molecular Physiology, Center for Integrative Physiology and Molecular Medicine, University of Saarland, Homburg, Germany
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18
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Houtekamer MC, Henckens MJAG, Mackey WE, Dunsmoor JE, Homberg JR, Kroes MCW. Investigating the efficacy of the reminder-extinction procedure to disrupt contextual threat memories in humans using immersive Virtual Reality. Sci Rep 2020; 10:16991. [PMID: 33046753 PMCID: PMC7550330 DOI: 10.1038/s41598-020-73139-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Accepted: 09/08/2020] [Indexed: 11/09/2022] Open
Abstract
Upon reactivation, consolidated memories can enter a temporary labile state and require restabilisation, known as reconsolidation. Interventions during this reconsolidation period can disrupt the reactivated memory. However, it is unclear whether different kinds of memory that depend on distinct brain regions all undergo reconsolidation. Evidence for reconsolidation originates from studies assessing amygdala-dependent memories using cue-conditioning paradigms in rodents, which were subsequently replicated in humans. Whilst studies providing evidence for reconsolidation of hippocampus-dependent memories in rodents have predominantly used context conditioning paradigms, studies in humans have used completely different paradigms such as tests for wordlists or stories. Here our objective was to bridge this paradigm gap between rodent and human studies probing reconsolidation of hippocampus-dependent memories. We modified a recently developed immersive Virtual Reality paradigm to test in humans whether contextual threat-conditioned memories can be disrupted by a reminder-extinction procedure that putatively targets reconsolidation. In contrast to our hypothesis, we found comparable recovery of contextual conditioned threat responses, and comparable retention of subjective measures of threat memory, episodic memory and exploration behaviour between the reminder-extinction and standard extinction groups. Our result provide no evidence that a reminder before extinction can prevent the return of context conditioned threat memories in humans.
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Affiliation(s)
- Maxime C Houtekamer
- Department of Cognitive Neuroscience, Donders Institute for Brain, Cognition, and Behaviour, Radboud University Nijmegen Medical Center, Kapittelweg 29, 6500 HB, Nijmegen, The Netherlands.
| | - Marloes J A G Henckens
- Department of Cognitive Neuroscience, Donders Institute for Brain, Cognition, and Behaviour, Radboud University Nijmegen Medical Center, Kapittelweg 29, 6500 HB, Nijmegen, The Netherlands
| | - Wayne E Mackey
- Center for Neural Science, New York University, New York, NY, 10003, USA
| | - Joseph E Dunsmoor
- Department of Psychiatry, University of Texas at Austin, Austin, TX, 78712, USA
| | - Judith R Homberg
- Department of Cognitive Neuroscience, Donders Institute for Brain, Cognition, and Behaviour, Radboud University Nijmegen Medical Center, Kapittelweg 29, 6500 HB, Nijmegen, The Netherlands
| | - Marijn C W Kroes
- Department of Cognitive Neuroscience, Donders Institute for Brain, Cognition, and Behaviour, Radboud University Nijmegen Medical Center, Kapittelweg 29, 6500 HB, Nijmegen, The Netherlands
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19
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Ormel L, Lauritzen KH, Schreiber R, Kunzelmann K, Gundersen V. GABA, but Not Bestrophin-1, Is Localized in Astroglial Processes in the Mouse Hippocampus and the Cerebellum. Front Mol Neurosci 2020; 13:135. [PMID: 32848599 PMCID: PMC7399226 DOI: 10.3389/fnmol.2020.00135] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Accepted: 07/07/2020] [Indexed: 11/13/2022] Open
Abstract
GABA is proposed to act as a gliotransmitter in the brain. Differences in GABA release from astroglia are thought to underlie differences in tonic inhibition between the cerebellum and the CA1 hippocampus. Here we used quantitative immunogold cytochemistry to localize and compare the levels of GABA in astroglia in these brain regions. We found that the density of GABA immunogold particles was similar in delicate processes of Bergman glia in the cerebellum and astrocytes in the CA1 hippocampus. The astrocytic GABA release is proposed to be mediated by, among others, the Ca2+ activated Cl- channel bestrophin-1. The bestrophin-1 antibodies did not show any significant bestrophin-1 signal in the brain of wt mice, nor in bestrophin-1 knockout mice. The bestrophin-1 signal was low both on Western blots and immunofluorescence laser scanning microscopic images. These results suggest that GABA is localized in astroglia, but in similar concentrations in the cerebellum and CA1 hippocampus, and thus cannot account for differences in tonic inhibition between these brain regions. Furthermore, our data seem to suggest that the GABA release from astroglia previously observed in the hippocampus and cerebellum occurs via mechanisms other than bestrophin-1.
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Affiliation(s)
- Lasse Ormel
- Section of Anatomy, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway.,Department of Neurology, Oslo University Hospital, Ullevål, Oslo, Norway
| | - Knut H Lauritzen
- Section of Anatomy, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway.,Research Institute of Internal Medicine, Oslo University Hospital, Rikshospitalet, Oslo, Norway
| | - Rainer Schreiber
- Department of Physiology, University of Regensburg, Regensburg, Germany
| | - Karl Kunzelmann
- Department of Physiology, University of Regensburg, Regensburg, Germany
| | - Vidar Gundersen
- Section of Anatomy, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway.,Section for Movement Disorders, Department of Neurology, Oslo University Hospital, Rikshospitalet, Oslo, Norway
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20
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Srivastava I, Vazquez-Juarez E, Henning L, Gómez-Galán M, Lindskog M. Blocking Astrocytic GABA Restores Synaptic Plasticity in Prefrontal Cortex of Rat Model of Depression. Cells 2020; 9:cells9071705. [PMID: 32708718 PMCID: PMC7408154 DOI: 10.3390/cells9071705] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Revised: 07/06/2020] [Accepted: 07/13/2020] [Indexed: 12/15/2022] Open
Abstract
A decrease in synaptic plasticity and/or a change in excitation/inhibition balance have been suggested as mechanisms underlying major depression disorder. However, given the crucial role of astrocytes in balancing synaptic function, particular attention should be given to the contribution of astrocytes in these mechanisms, especially since previous findings show that astrocytes are affected and exhibit reactive-like features in depression. Moreover, it has been shown that reactive astrocytes increase the synthesis and release of GABA, contributing significantly to tonic GABA inhibition. In this study we found decreased plasticity and increased tonic GABA inhibition in the prelimbic area in acute slices from the medial prefrontal cortex in the Flinders Sensitive Line (FSL) rat model of depression. The tonic inhibition can be reduced by either blocking astrocytic intracellular Ca2+ signaling or by reducing astrocytic GABA through inhibition of the synthesizing enzyme MAO-B with Selegiline. Blocking GABA synthesis also restores the impaired synaptic plasticity in the FSL prefrontal cortex, providing a new antidepressant mechanism of Selegiline.
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Affiliation(s)
- Ipsit Srivastava
- Dep. Neurobiology, Care Sciences and Society, Karolinska Institutet, 171 77 Stockholm, Sweden; (I.S.); (E.V.-J.); (L.H.)
| | - Erika Vazquez-Juarez
- Dep. Neurobiology, Care Sciences and Society, Karolinska Institutet, 171 77 Stockholm, Sweden; (I.S.); (E.V.-J.); (L.H.)
| | - Lukas Henning
- Dep. Neurobiology, Care Sciences and Society, Karolinska Institutet, 171 77 Stockholm, Sweden; (I.S.); (E.V.-J.); (L.H.)
| | - Marta Gómez-Galán
- Dep. Physiology and Pharmacology, Karolinska Institutet, 171 77 Stockholm, Sweden
- Correspondence: (M.G.-G.); (M.L.)
| | - Maria Lindskog
- Dep. Neurobiology, Care Sciences and Society, Karolinska Institutet, 171 77 Stockholm, Sweden; (I.S.); (E.V.-J.); (L.H.)
- Correspondence: (M.G.-G.); (M.L.)
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21
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Pandit S, Neupane C, Woo J, Sharma R, Nam MH, Lee GS, Yi MH, Shin N, Kim DW, Cho H, Jeon BH, Kim HW, Lee CJ, Park JB. Bestrophin1-mediated tonic GABA release from reactive astrocytes prevents the development of seizure-prone network in kainate-injected hippocampi. Glia 2019; 68:1065-1080. [PMID: 31833596 DOI: 10.1002/glia.23762] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Revised: 11/25/2019] [Accepted: 11/28/2019] [Indexed: 12/22/2022]
Abstract
Tonic extrasynaptic GABAA receptor (GABAA R) activation is under the tight control of tonic GABA release from astrocytes to maintain the brain's excitation/inhibition (E/I) balance; any slight E/I balance disturbance can cause serious pathological conditions including epileptic seizures. However, the pathophysiological role of tonic GABA release from astrocytes has not been tested in epileptic seizures. Here, we report that pharmacological or genetic intervention of the GABA-permeable Bestrophin-1 (Best1) channel prevented the generation of tonic GABA inhibition, disinhibiting CA1 pyramidal neuronal firing and augmenting seizure susceptibility in kainic acid (KA)-induced epileptic mice. Astrocyte-specific Best1 over-expression in KA-injected Best1 knockout mice fully restored the generation of tonic GABA inhibition and effectively suppressed seizure susceptibility. We demonstrate for the first time that tonic GABA from reactive astrocytes strongly contributes to the compensatory shift of E/I balance in epileptic hippocampi, serving as a good therapeutic target against altered E/I balance in epileptic seizures.
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Affiliation(s)
- Sudip Pandit
- Department of Medical Science, College of Medicine and Brain Research Institute, Chungnam National University, Daejeon, Republic of Korea.,Department of Physiology, College of Medicine and Brain Research Institute, Chungnam National University, Daejeon, Republic of Korea
| | - Chiranjivi Neupane
- Department of Medical Science, College of Medicine and Brain Research Institute, Chungnam National University, Daejeon, Republic of Korea.,Department of Physiology, College of Medicine and Brain Research Institute, Chungnam National University, Daejeon, Republic of Korea
| | - Junsung Woo
- Center for Glia-Neuron Interaction and Neuroscience, Korea Institute of Science and Technology (KIST), Seoul, Republic of Korea
| | - Ramesh Sharma
- Department of Medical Science, College of Medicine and Brain Research Institute, Chungnam National University, Daejeon, Republic of Korea.,Department of Physiology, College of Medicine and Brain Research Institute, Chungnam National University, Daejeon, Republic of Korea
| | - Min-Ho Nam
- Center for Glia-Neuron Interaction and Neuroscience, Korea Institute of Science and Technology (KIST), Seoul, Republic of Korea
| | - Gyu-Seung Lee
- Department of Physiology, College of Medicine and Brain Research Institute, Chungnam National University, Daejeon, Republic of Korea
| | - Min-Hee Yi
- Department of Anatomy, College of Medicine and Brain Research Institute, Chungnam National University, Daejeon, Republic of Korea
| | - Nara Shin
- Department of Medical Science, College of Medicine and Brain Research Institute, Chungnam National University, Daejeon, Republic of Korea.,Department of Anatomy, College of Medicine and Brain Research Institute, Chungnam National University, Daejeon, Republic of Korea
| | - Dong Woon Kim
- Department of Medical Science, College of Medicine and Brain Research Institute, Chungnam National University, Daejeon, Republic of Korea.,Department of Anatomy, College of Medicine and Brain Research Institute, Chungnam National University, Daejeon, Republic of Korea
| | - Hyunsill Cho
- Department of Physiology, College of Medicine and Brain Research Institute, Chungnam National University, Daejeon, Republic of Korea
| | - Byeong Hwa Jeon
- Department of Medical Science, College of Medicine and Brain Research Institute, Chungnam National University, Daejeon, Republic of Korea.,Department of Physiology, College of Medicine and Brain Research Institute, Chungnam National University, Daejeon, Republic of Korea
| | - Hyun-Woo Kim
- Department of Medical Science, College of Medicine and Brain Research Institute, Chungnam National University, Daejeon, Republic of Korea.,Department of Physiology, College of Medicine and Brain Research Institute, Chungnam National University, Daejeon, Republic of Korea
| | - C Justin Lee
- Center for Glia-Neuron Interaction and Neuroscience, Korea Institute of Science and Technology (KIST), Seoul, Republic of Korea.,Center for Cognition and Sociality, Institute for Basic Science, Daejeon, Republic of Korea
| | - Jin Bong Park
- Department of Medical Science, College of Medicine and Brain Research Institute, Chungnam National University, Daejeon, Republic of Korea.,Department of Physiology, College of Medicine and Brain Research Institute, Chungnam National University, Daejeon, Republic of Korea
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22
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Garcia VJ, Rushton DJ, Tom CM, Allen ND, Kemp PJ, Svendsen CN, Mattis VB. Huntington's Disease Patient-Derived Astrocytes Display Electrophysiological Impairments and Reduced Neuronal Support. Front Neurosci 2019; 13:669. [PMID: 31316341 PMCID: PMC6610155 DOI: 10.3389/fnins.2019.00669] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Accepted: 06/11/2019] [Indexed: 12/03/2022] Open
Abstract
In Huntington’s disease (HD), while the ubiquitously expressed mutant Huntingtin (mtHTT) protein primarily compromises striatal and cortical neurons, glia also undergo disease-contributing alterations. Existing HD models using human induced pluripotent stem cells (iPSCs) have not extensively characterized the role of mtHTT in patient-derived astrocytes. Here physiologically mature astrocytes are generated from HD patient iPSCs. These human astrocytes exhibit hallmark HD phenotypes that occur in mouse models, including impaired inward rectifying K+ currents, lengthened spontaneous Ca2+ waves and reduced cell membrane capacitance. HD astrocytes in co-culture provided reduced support for the maturation of iPSC-derived neurons. In addition, neurons exposed to chronic glutamate stimulation are not protected by HD astrocytes. This iPSC-based HD model demonstrates the critical effects of mtHTT on human astrocytes, which not only broadens the understanding of disease susceptibility beyond cortical and striatal neurons but also increases potential drug targets.
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Affiliation(s)
- Veronica J Garcia
- Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, CA, United States
| | - David J Rushton
- Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, CA, United States.,Divisions of Biomedicine and Neuroscience, School of Biosciences, Cardiff University, Cardiff, United Kingdom
| | - Colton M Tom
- Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, CA, United States
| | - Nicholas D Allen
- Divisions of Biomedicine and Neuroscience, School of Biosciences, Cardiff University, Cardiff, United Kingdom
| | - Paul J Kemp
- Divisions of Biomedicine and Neuroscience, School of Biosciences, Cardiff University, Cardiff, United Kingdom
| | - Clive N Svendsen
- Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, CA, United States
| | - Virginia B Mattis
- Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, CA, United States
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23
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Diverse Actions of Astrocytes in GABAergic Signaling. Int J Mol Sci 2019; 20:ijms20122964. [PMID: 31216630 PMCID: PMC6628243 DOI: 10.3390/ijms20122964] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2019] [Revised: 06/10/2019] [Accepted: 06/14/2019] [Indexed: 01/06/2023] Open
Abstract
An imbalance of excitatory and inhibitory neurotransmission leading to over excitation plays a crucial role in generating seizures, while enhancing GABAergic mechanisms are critical in terminating seizures. In recent years, it has been reported in many studies that astrocytes are deeply involved in synaptic transmission. Astrocytes form a critical component of the “tripartite” synapses by wrapping around the pre- and post-synaptic elements. From this location, astrocytes are known to greatly influence the dynamics of ions and transmitters in the synaptic cleft. Despite recent extensive research on excitatory tripartite synapses, inhibitory tripartite synapses have received less attention, even though they influence inhibitory synaptic transmission by affecting chloride and GABA concentration dynamics. In this review, we will discuss the diverse actions of astrocytic chloride and GABA homeostasis at GABAergic tripartite synapses. We will then consider the pathophysiological impacts of disturbed GABA homeostasis at the tripartite synapse.
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24
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Mahmoud S, Gharagozloo M, Simard C, Gris D. Astrocytes Maintain Glutamate Homeostasis in the CNS by Controlling the Balance between Glutamate Uptake and Release. Cells 2019; 8:E184. [PMID: 30791579 PMCID: PMC6406900 DOI: 10.3390/cells8020184] [Citation(s) in RCA: 346] [Impact Index Per Article: 69.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Revised: 02/15/2019] [Accepted: 02/19/2019] [Indexed: 01/26/2023] Open
Abstract
Glutamate is one of the most prevalent neurotransmitters released by excitatory neurons in the central nervous system (CNS); however, residual glutamate in the extracellular space is, potentially, neurotoxic. It is now well-established that one of the fundamental functions of astrocytes is to uptake most of the synaptically-released glutamate, which optimizes neuronal functions and prevents glutamate excitotoxicity. In the CNS, glutamate clearance is mediated by glutamate uptake transporters expressed, principally, by astrocytes. Interestingly, recent studies demonstrate that extracellular glutamate stimulates Ca2+ release from the astrocytes' intracellular stores, which triggers glutamate release from astrocytes to the adjacent neurons, mostly by an exocytotic mechanism. This released glutamate is believed to coordinate neuronal firing and mediate their excitatory or inhibitory activity. Therefore, astrocytes contribute to glutamate homeostasis in the CNS, by maintaining the balance between their opposing functions of glutamate uptake and release. This dual function of astrocytes represents a potential therapeutic target for CNS diseases associated with glutamate excitotoxicity. In this regard, we summarize the molecular mechanisms of glutamate uptake and release, their regulation, and the significance of both processes in the CNS. Also, we review the main features of glutamate metabolism and glutamate excitotoxicity and its implication in CNS diseases.
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Affiliation(s)
- Shaimaa Mahmoud
- Program of Immunology, Department of Pharmacology-Physiology, Faculty of Medicine and Health Sciences, University of Sherbrooke, Sherbrooke, QC J1H 5N4, Canada.
| | - Marjan Gharagozloo
- Program of Immunology, Department of Pharmacology-Physiology, Faculty of Medicine and Health Sciences, University of Sherbrooke, Sherbrooke, QC J1H 5N4, Canada.
| | - Camille Simard
- Program of Immunology, Department of Pharmacology-Physiology, Faculty of Medicine and Health Sciences, University of Sherbrooke, Sherbrooke, QC J1H 5N4, Canada.
| | - Denis Gris
- Program of Immunology, Department of Pharmacology-Physiology, Faculty of Medicine and Health Sciences, University of Sherbrooke, Sherbrooke, QC J1H 5N4, Canada.
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25
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New Roles for Old Glue: Astrocyte Function in Synaptic Plasticity and Neurological Disorders. Int Neurourol J 2018; 22:S106-114. [PMID: 30396259 PMCID: PMC6234728 DOI: 10.5213/inj.1836214.107] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Accepted: 10/10/2018] [Indexed: 01/02/2023] Open
Abstract
Previously believed to solely play a supportive role in the central nervous system, astrocytes are now considered active players in normal brain function. Evidence in recent decades extends their contributions beyond the classically held brain glue role; it's now known that astrocytes act as a unique excitable component with functions extending into local network modulation, synaptic plasticity, and memory formation, and postinjury repair. In this review article, we highlight our growing understanding of astrocyte function and physiology, the increasing role of gliotransmitters in neuron-glia communication, and the role of astrocytes in modulating synaptic plasticity and cognitive function. Owing to the duality of both beneficial and deleterious roles attributed to astrocytes, we also discuss the implications of this new knowledge as it applies to neurological disorders including Alzheimer disease, epilepsy, and schizophrenia.
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26
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Jung SH, Song HY, Hyun YS, Kim YC, Whang I, Choi TY, Jo S. A Brain Atlas of the Long Arm Octopus, Octopus minor. Exp Neurobiol 2018; 27:257-266. [PMID: 30181688 PMCID: PMC6120969 DOI: 10.5607/en.2018.27.4.257] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2018] [Revised: 08/05/2018] [Accepted: 08/09/2018] [Indexed: 12/05/2022] Open
Abstract
Cephalopods have the most advanced nervous systems and intelligent behavior among all invertebrates. Their brains provide comparative insights for understanding the molecular and functional origins of the human brain. Although brain maps that contain information on the organization of each subregion are necessary for a study on the brain, no whole brain atlas for adult cephalopods has been constructed to date. Here, we obtained sagittal and coronal sections covering the entire brain of adult Octopus minor (Sasaki), which belongs to the genus with the most species in the class Cephalopoda and is commercially available in East Asia throughout the year. Sections were stained using Hematoxylin and Eosin (H&E) to visualize the cellular nuclei and subregions. H&E images of the serial sections were obtained at 30~70-µm intervals for the sagittal plain and at 40~80-µm intervals for the coronal plain. Setting the midline point of the posterior end as the fiducial point, we also established the distance coordinates of each image. We found that the brain had the typical brain structure of the Octopodiformes. A number of subregions were discriminated by a Hematoxylin-positive layer, the thickness and neuronal distribution pattern of which varied markedly depending upon the region. We identified more than 70 sub-regions based on delineations of representative H&E images. This is the first brain atlas, not only for an Octopodiformes species but also among adult cephalopods, and we anticipate that this atlas will provide a valuable resource for comparative neuroscience research.
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Affiliation(s)
- Seung-Hyun Jung
- Department of Genetic Resources Research, National Marine Biodiversity Institute of Korea (MABIK), Seocheon 33662, Korea
| | - Ha Yeun Song
- Department of Genetic Resources Research, National Marine Biodiversity Institute of Korea (MABIK), Seocheon 33662, Korea
| | - Young Se Hyun
- Department of Genetic Resources Research, National Marine Biodiversity Institute of Korea (MABIK), Seocheon 33662, Korea
| | - Yu-Cheol Kim
- Department of Genetic Resources Research, National Marine Biodiversity Institute of Korea (MABIK), Seocheon 33662, Korea
| | - Ilson Whang
- Department of Genetic Resources Research, National Marine Biodiversity Institute of Korea (MABIK), Seocheon 33662, Korea
| | - Tae-Young Choi
- Department of Genetic Resources Research, National Marine Biodiversity Institute of Korea (MABIK), Seocheon 33662, Korea
| | - Seonmi Jo
- Department of Genetic Resources Research, National Marine Biodiversity Institute of Korea (MABIK), Seocheon 33662, Korea
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27
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Chun H, An H, Lim J, Woo J, Lee J, Ryu H, Lee CJ. Astrocytic proBDNF and Tonic GABA Distinguish Active versus Reactive Astrocytes in Hippocampus. Exp Neurobiol 2018; 27:155-170. [PMID: 30022867 PMCID: PMC6050417 DOI: 10.5607/en.2018.27.3.155] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Revised: 06/26/2018] [Accepted: 06/30/2018] [Indexed: 01/18/2023] Open
Abstract
Astrocytes are the most abundant cell type in the brain and they make close contacts with neurons and blood vessels. They respond dynamically to various environmental stimuli and change their morphological and functional properties. Both physiological and pathological stimuli can induce versatile changes in astrocytes, as this phenomenon is referred to as ‘astrocytic plasticity’. However, the molecular and cellular mechanisms of astrocytic plasticity in response to various stimuli remain elusive, except for the presence of hypertrophy, a conspicuous structural change which is frequently observed in activated or reactive astrocytes. Here, we investigated differential characteristics of astrocytic plasticity in a stimulus-dependent manner. Strikingly, a stab wound brain injury lead to hypertrophy of astrocytes accompanied by increased GABA expression and tonic GABA release in mouse CA1 hippocampus. In contrast, the mice experiencing enriched environment exhibited astrocytic hypertrophy with enhanced proBDNF immunoreactivity but without GABA signal. Based on the results, we define proBDNF-positive/GABA-negative hypertrophic astrocytes as ‘active’ astrocytes and GABA-positive hypertrophic astrocytes as ‘reactive’ astrocytes, respectively. We propose for the first time that astrocytic proBDNF can be a bona fide molecular marker of the active astrocytes, which are distinct from the reactive astrocytes which show hypertrophy but with aberrant GABA.
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Affiliation(s)
- Heejung Chun
- Center for Neuroscience and Functional Connectomics, Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea.,Center for Glia-Neuron Interaction, Brain Science Institute, KIST, Seoul 02792, Korea
| | - Heeyoung An
- Center for Neuroscience and Functional Connectomics, Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea.,Center for Glia-Neuron Interaction, Brain Science Institute, KIST, Seoul 02792, Korea.,KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul 02841, Korea
| | - Jiwoon Lim
- Center for Glia-Neuron Interaction, Brain Science Institute, KIST, Seoul 02792, Korea
| | - Junsung Woo
- Center for Neuroscience and Functional Connectomics, Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea
| | - Jaekwang Lee
- Center for Neuroscience and Functional Connectomics, Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea
| | - Hoon Ryu
- Center for Neuromedicine, Brain Science Institute, KIST, Seoul 02792, Korea.,Boston University Alzheimer's Disease Center and Department of Neurology, Boston University School of Medicine, Boston, MA 02118, USA
| | - C Justin Lee
- Center for Neuroscience and Functional Connectomics, Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea.,Center for Glia-Neuron Interaction, Brain Science Institute, KIST, Seoul 02792, Korea.,Division of Bio-Medical Science & Technology, KIST School, KIST, Seoul 02792, Korea
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28
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Lia A, Zonta M, Requie LM, Carmignoto G. Dynamic interactions between GABAergic and astrocytic networks. Neurosci Lett 2018; 689:14-20. [PMID: 29908949 DOI: 10.1016/j.neulet.2018.06.026] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Revised: 06/12/2018] [Accepted: 06/13/2018] [Indexed: 10/28/2022]
Abstract
Brain network activity derives from the concerted action of different cell populations. Together with interneurons, astrocytes play fundamental roles in shaping the inhibition in brain circuitries and modulating neuronal transmission. In this review, we summarize past and recent findings that reveal in neural networks the importance of the interaction between GABAergic signaling and astrocytes and discuss its physiological and pathological relevance.
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Affiliation(s)
- Annamaria Lia
- University of Padua, Department of Biomedical Sciences, Padua, Italy; CNR, Neuroscience Institute, Padua, Italy
| | - Micaela Zonta
- University of Padua, Department of Biomedical Sciences, Padua, Italy; CNR, Neuroscience Institute, Padua, Italy.
| | - Linda Maria Requie
- University of Padua, Department of Biomedical Sciences, Padua, Italy; CNR, Neuroscience Institute, Padua, Italy
| | - Giorgio Carmignoto
- University of Padua, Department of Biomedical Sciences, Padua, Italy; CNR, Neuroscience Institute, Padua, Italy
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29
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Wilson CS, Mongin AA. The signaling role for chloride in the bidirectional communication between neurons and astrocytes. Neurosci Lett 2018; 689:33-44. [PMID: 29329909 DOI: 10.1016/j.neulet.2018.01.012] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2017] [Revised: 01/04/2018] [Accepted: 01/05/2018] [Indexed: 01/01/2023]
Abstract
It is well known that the electrical signaling in neuronal networks is modulated by chloride (Cl-) fluxes via the inhibitory GABAA and glycine receptors. Here, we discuss the putative contribution of Cl- fluxes and intracellular Cl- to other forms of information transfer in the CNS, namely the bidirectional communication between neurons and astrocytes. The manuscript (i) summarizes the generic functions of Cl- in cellular physiology, (ii) recaps molecular identities and properties of Cl- transporters and channels in neurons and astrocytes, and (iii) analyzes emerging studies implicating Cl- in the modulation of neuroglial communication. The existing literature suggests that neurons can alter astrocytic Cl- levels in a number of ways; via (a) the release of neurotransmitters and activation of glial transporters that have intrinsic Cl- conductance, (b) the metabotropic receptor-driven changes in activity of the electroneutral cation-Cl- cotransporter NKCC1, and (c) the transient, activity-dependent changes in glial cell volume which open the volume-regulated Cl-/anion channel VRAC. Reciprocally, astrocytes are thought to alter neuronal [Cl-]i through either (a) VRAC-mediated release of the inhibitory gliotransmitters, GABA and taurine, which open neuronal GABAA and glycine receptor/Cl- channels, or (b) the gliotransmitter-driven stimulation of NKCC1. The most important recent developments in this area are the identification of the molecular composition and functional heterogeneity of brain VRAC channels, and the discovery of a new cytosolic [Cl-] sensor - the Wnk family protein kinases. With new work in the field, our understanding of the role of Cl- in information processing within the CNS is expected to be significantly updated.
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Affiliation(s)
- Corinne S Wilson
- Department of Neuroscience and Experimental Therapeutics, Albany Medical College, Albany, NY, United States
| | - Alexander A Mongin
- Department of Neuroscience and Experimental Therapeutics, Albany Medical College, Albany, NY, United States; Department of Biophysics and Functional Diagnostics, Siberian State Medical University, Tomsk, Russian Federation.
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30
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Abstract
Astrocytes are neural cells of ectodermal, neuroepithelial origin that provide for homeostasis and defense of the central nervous system (CNS). Astrocytes are highly heterogeneous in morphological appearance; they express a multitude of receptors, channels, and membrane transporters. This complement underlies their remarkable adaptive plasticity that defines the functional maintenance of the CNS in development and aging. Astrocytes are tightly integrated into neural networks and act within the context of neural tissue; astrocytes control homeostasis of the CNS at all levels of organization from molecular to the whole organ.
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Affiliation(s)
- Alexei Verkhratsky
- The University of Manchester , Manchester , United Kingdom ; Achúcarro Basque Center for Neuroscience, IKERBASQUE, Basque Foundation for Science , Bilbao , Spain ; Department of Neuroscience, University of the Basque Country UPV/EHU and CIBERNED, Leioa, Spain ; Center for Basic and Translational Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen , Copenhagen , Denmark ; and Center for Translational Neuromedicine, University of Rochester Medical Center , Rochester, New York
| | - Maiken Nedergaard
- The University of Manchester , Manchester , United Kingdom ; Achúcarro Basque Center for Neuroscience, IKERBASQUE, Basque Foundation for Science , Bilbao , Spain ; Department of Neuroscience, University of the Basque Country UPV/EHU and CIBERNED, Leioa, Spain ; Center for Basic and Translational Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen , Copenhagen , Denmark ; and Center for Translational Neuromedicine, University of Rochester Medical Center , Rochester, New York
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31
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Verkhratsky A, Nedergaard M. Physiology of Astroglia. Physiol Rev 2018; 98:239-389. [PMID: 29351512 PMCID: PMC6050349 DOI: 10.1152/physrev.00042.2016] [Citation(s) in RCA: 951] [Impact Index Per Article: 158.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Revised: 03/22/2017] [Accepted: 04/27/2017] [Indexed: 02/07/2023] Open
Abstract
Astrocytes are neural cells of ectodermal, neuroepithelial origin that provide for homeostasis and defense of the central nervous system (CNS). Astrocytes are highly heterogeneous in morphological appearance; they express a multitude of receptors, channels, and membrane transporters. This complement underlies their remarkable adaptive plasticity that defines the functional maintenance of the CNS in development and aging. Astrocytes are tightly integrated into neural networks and act within the context of neural tissue; astrocytes control homeostasis of the CNS at all levels of organization from molecular to the whole organ.
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Affiliation(s)
- Alexei Verkhratsky
- The University of Manchester , Manchester , United Kingdom ; Achúcarro Basque Center for Neuroscience, IKERBASQUE, Basque Foundation for Science , Bilbao , Spain ; Department of Neuroscience, University of the Basque Country UPV/EHU and CIBERNED, Leioa, Spain ; Center for Basic and Translational Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen , Copenhagen , Denmark ; and Center for Translational Neuromedicine, University of Rochester Medical Center , Rochester, New York
| | - Maiken Nedergaard
- The University of Manchester , Manchester , United Kingdom ; Achúcarro Basque Center for Neuroscience, IKERBASQUE, Basque Foundation for Science , Bilbao , Spain ; Department of Neuroscience, University of the Basque Country UPV/EHU and CIBERNED, Leioa, Spain ; Center for Basic and Translational Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen , Copenhagen , Denmark ; and Center for Translational Neuromedicine, University of Rochester Medical Center , Rochester, New York
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32
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Brawek B, Chesters R, Klement D, Müller J, Lerdkrai C, Hermes M, Garaschuk O. A bell-shaped dependence between amyloidosis and GABA accumulation in astrocytes in a mouse model of Alzheimer's disease. Neurobiol Aging 2017; 61:187-197. [PMID: 29107186 DOI: 10.1016/j.neurobiolaging.2017.09.028] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Revised: 09/25/2017] [Accepted: 09/27/2017] [Indexed: 10/18/2022]
Abstract
Functioning at the interface between the nervous and immune systems, in the amyloid-depositing brain, astrocytes become hypertrophic and accumulate around senile plaques. Moreover, hippocampal astrocytes upregulate their γ-aminobutyric acid (GABA) content and enhance tonic inhibition, likely causing local circuit imbalance. It remains, however, unclear whether this effect is hippocampus specific and how it is regulated during disease progression. Here, we studied changes in astrocytic morphology and GABA content in the frontal cortex and dentate gyrus of control and amyloid-depositing mice. Healthy aging was accompanied by a transient increase in astrocytic GABA content at middle age and region-specific alterations of soma size. In contrast, amyloid deposition caused a gradual cortex-accentuated increase in soma size. Importantly, our data uncovered a bell-shaped relationship between the mouse age and astrocytic GABA content in both brain regions. Moreover, in mice carrying an Alzheimer's disease-related mutation in presenilin 1, astrocytes accumulated GABA even in the absence of amyloidosis. These data question the proposed inhibition of astrocytic GABA synthesis as a universal strategy for treating network dysfunction in Alzheimer's disease.
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Affiliation(s)
- Bianca Brawek
- Department of Neurophysiology, Institute of Physiology, University of Tübingen, Tübingen, Germany
| | - Robert Chesters
- Department of Neurophysiology, Institute of Physiology, University of Tübingen, Tübingen, Germany
| | - Daniel Klement
- Department of Neurophysiology, Institute of Physiology, University of Tübingen, Tübingen, Germany
| | - Julia Müller
- Department of Neurophysiology, Institute of Physiology, University of Tübingen, Tübingen, Germany
| | - Chommanad Lerdkrai
- Department of Neurophysiology, Institute of Physiology, University of Tübingen, Tübingen, Germany
| | - Marina Hermes
- Department of Neurophysiology, Institute of Physiology, University of Tübingen, Tübingen, Germany
| | - Olga Garaschuk
- Department of Neurophysiology, Institute of Physiology, University of Tübingen, Tübingen, Germany.
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33
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Szabó Z, Héja L, Szalay G, Kékesi O, Füredi A, Szebényi K, Dobolyi Á, Orbán TI, Kolacsek O, Tompa T, Miskolczy Z, Biczók L, Rózsa B, Sarkadi B, Kardos J. Extensive astrocyte synchronization advances neuronal coupling in slow wave activity in vivo. Sci Rep 2017; 7:6018. [PMID: 28729692 PMCID: PMC5519671 DOI: 10.1038/s41598-017-06073-7] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Accepted: 05/26/2017] [Indexed: 01/19/2023] Open
Abstract
Slow wave activity (SWA) is a characteristic brain oscillation in sleep and quiet wakefulness. Although the cell types contributing to SWA genesis are not yet identified, the principal role of neurons in the emergence of this essential cognitive mechanism has not been questioned. To address the possibility of astrocytic involvement in SWA, we used a transgenic rat line expressing a calcium sensitive fluorescent protein in both astrocytes and interneurons and simultaneously imaged astrocytic and neuronal activity in vivo. Here we demonstrate, for the first time, that the astrocyte network display synchronized recurrent activity in vivo coupled to UP states measured by field recording and neuronal calcium imaging. Furthermore, we present evidence that extensive synchronization of the astrocytic network precedes the spatial build-up of neuronal synchronization. The earlier extensive recruitment of astrocytes in the synchronized activity is reinforced by the observation that neurons surrounded by active astrocytes are more likely to join SWA, suggesting causality. Further supporting this notion, we demonstrate that blockade of astrocytic gap junctional communication or inhibition of astrocytic Ca2+ transients reduces the ratio of both astrocytes and neurons involved in SWA. These in vivo findings conclusively suggest a causal role of the astrocytic syncytium in SWA generation.
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Affiliation(s)
- Zsolt Szabó
- Institute of Organic Chemistry, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Magyar tudósok körútja 2, 1117, Budapest, Hungary
| | - László Héja
- Institute of Organic Chemistry, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Magyar tudósok körútja 2, 1117, Budapest, Hungary.
| | - Gergely Szalay
- Institute of Experimental Medicine, Hungarian Academy of Sciences, Szigony 43, 1083, Budapest, Hungary
| | - Orsolya Kékesi
- Institute of Organic Chemistry, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Magyar tudósok körútja 2, 1117, Budapest, Hungary
| | - András Füredi
- Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Magyar tudósok körútja 2, 1117, Budapest, Hungary.,Institute of Cancer Research, Medical University Wien, Borschkegasse 8a, 1090, Wien, Austria
| | - Kornélia Szebényi
- Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Magyar tudósok körútja 2, 1117, Budapest, Hungary.,Institute of Cancer Research, Medical University Wien, Borschkegasse 8a, 1090, Wien, Austria
| | - Árpád Dobolyi
- MTA-ELTE Laboratory of Molecular and Systems Neurobiology, Department of Physiology and Neurobiology, Eötvös Loránd University, Pázmány Péter sétány 1C, 1117, Budapest, Hungary
| | - Tamás I Orbán
- Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Magyar tudósok körútja 2, 1117, Budapest, Hungary
| | - Orsolya Kolacsek
- Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Magyar tudósok körútja 2, 1117, Budapest, Hungary
| | - Tamás Tompa
- Institute of Experimental Medicine, Hungarian Academy of Sciences, Szigony 43, 1083, Budapest, Hungary
| | - Zsombor Miskolczy
- Institute of Materials and Environmental Chemistry, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Magyar tudósok körútja 2, 1117, Budapest, Hungary
| | - László Biczók
- Institute of Materials and Environmental Chemistry, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Magyar tudósok körútja 2, 1117, Budapest, Hungary
| | - Balázs Rózsa
- Institute of Experimental Medicine, Hungarian Academy of Sciences, Szigony 43, 1083, Budapest, Hungary
| | - Balázs Sarkadi
- Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Magyar tudósok körútja 2, 1117, Budapest, Hungary
| | - Julianna Kardos
- Institute of Organic Chemistry, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Magyar tudósok körútja 2, 1117, Budapest, Hungary
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34
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Oh SJ, Lee CJ. Distribution and Function of the Bestrophin-1 (Best1) Channel in the Brain. Exp Neurobiol 2017; 26:113-121. [PMID: 28680296 PMCID: PMC5491579 DOI: 10.5607/en.2017.26.3.113] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Revised: 06/08/2017] [Accepted: 06/08/2017] [Indexed: 12/29/2022] Open
Abstract
Bestrophin-1 (Best1) is a calcium-activated anion channel identified from retinal pigment epithelium where human mutations are associated with Best's macular degeneration. Best1 is known to be expressed in a variety of tissues including the brain, and is thought to be involved in many physiological processes. This review focuses on the current state of knowledge on aspects of expression and function of Best1 in the brain. Best1 protein is observed in cortical and hippocampal astrocytes, in cerebellar Bergmann glia and lamellar astrocytes, in thalamic reticular neurons, in meninges and in the epithelial cells of the choroid plexus. The most prominent feature of Best1 is its significant permeability to glutamate and GABA in addition to chloride ions because glutamate and GABA are important transmitters in the brain. Under physiological conditions, both Best1-mediated glutamate release and tonic GABA release from astrocytes modulate neuronal excitability, synaptic transmission and synaptic plasticity. Under pathological conditions such as neuroinflammation and neurodegeneration, reactive astrocytes phenotypically switch from GABA-negative to GABA-producing and redistribute Best1 from the perisynaptic microdomains to the soma and processes to tonically release GABA via Best1. This implicates that tonic GABA release from reactive astrocyte via redistributed Best1 is a common phenomenon that occur in various pathological conditions with astrogliosis such as traumatic brain injury, neuroinflammation, neurodegeneration, and hypoxic and ischemic insults. These properties of Best1, including the permeation and release of glutamate and GABA and its redistribution in reactive astrocytes, promise us exciting discoveries of novel brain functions to be uncovered in the future.
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Affiliation(s)
- Soo-Jin Oh
- Center for Neuroscience, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea.,Convergence Research Center for Diagnosis, Treatment and Care System of Dementia, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea.,Center for Glia-Neuron Interaction, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea
| | - C Justin Lee
- Center for Neuroscience, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea.,Center for Glia-Neuron Interaction, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea
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Min JO, Yoon BE. Glia and gliotransmitters on carbon nanotubes. NANO REVIEWS & EXPERIMENTS 2017; 8:1323853. [PMID: 30410703 PMCID: PMC6167025 DOI: 10.1080/20022727.2017.1323853] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/31/2016] [Revised: 11/20/2016] [Accepted: 05/11/2017] [Indexed: 11/11/2022]
Abstract
Introduction: Functionalised carbon nanotubes (CNTs) have been shown to be promising biomaterials in neural systems, such as CNT -based nerve scaffolds to drive nerve regeneration. CNTs have been shown to modulate neuronal growth and improve electrical conductivity of neurons. Methods: Cultured astrocytes on the functionalized CNTs (PEG, caroboxyl group) were assessed for distribution of GABA, glutamate uptake assay using isotope and change of conductance of CNTs by ATP. Immunostaining of GABA using anti-GABA (red), anti-GFAP (green) antibody in primary cortical astrocytes on MW-CNT and PDL coverslips. Results: The functionalization of CNTs has improved their solubility and biocompatibility and alters their cellular interaction pathways. Recently, CNTs have been shown to modulate morphofunctional characteristics of glia as well as neurons. Among the various types of glia, astrocytes express diverse receptors for corresponding neurotransmitters and release gliotransmitters, including glutamate, adenosine triphosphate, and γ-amino butyric acid. Gliotransmitters are primarily released from astrocytes and play important roles in glia–neuron crosstalk. Conclusion: This review focuses on the effects of CNTs on glial cells and discusses how functionalized CNTs can modulate morphology and gliotransmitters of glial cells. Based on exciting new findings, they look to be a promising material for use in brain disease therapy or neuroprosthetics.
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Affiliation(s)
- Joo-Ok Min
- Department of Nanobiomedical Science, Dankook University, Cheonan-si, Chungnam, Republic of Korea
| | - Bo-Eun Yoon
- Department of Nanobiomedical Science, Dankook University, Cheonan-si, Chungnam, Republic of Korea.,Department of Molecular Biology, Dankook University, Cheonan-si, Chungnam, Republic of Korea
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36
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Acosta C, Anderson HD, Anderson CM. Astrocyte dysfunction in Alzheimer disease. J Neurosci Res 2017; 95:2430-2447. [PMID: 28467650 DOI: 10.1002/jnr.24075] [Citation(s) in RCA: 161] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Revised: 04/07/2017] [Accepted: 04/10/2017] [Indexed: 12/11/2022]
Abstract
Astrocytes are glial cells that are distributed throughout the central nervous system in an arrangement optimal for chemical and physical interaction with neuronal synapses and brain blood supply vessels. Neurotransmission modulates astrocytic excitability by activating an array of cell surface receptors and transporter proteins, resulting in dynamic changes in intracellular Ca2+ or Na+ . Ionic and electrogenic astrocytic changes, in turn, drive vital cell nonautonomous effects supporting brain function, including regulation of synaptic activity, neuronal metabolism, and regional blood supply. Alzheimer disease (AD) is associated with aberrant oligomeric amyloid β generation, which leads to extensive proliferation of astrocytes with a reactive phenotype and abnormal regulation of these processes. Astrocytic morphology, Ca2+ responses, extracellular K+ removal, glutamate transport, amyloid clearance, and energy metabolism are all affected in AD, resulting in a deleterious set of effects that includes glutamate excitotoxicity, impaired synaptic plasticity, reduced carbon delivery to neurons for oxidative phosphorylation, and dysregulated linkages between neuronal energy demand and regional blood supply. This review summarizes how astrocytes are affected in AD and describes how these changes are likely to influence brain function. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Crystal Acosta
- Department of Pharmacology and Therapeutics, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, Canada.,Canadian Centre for Agri-food Research in Health and Medicine, St. Boniface Hospital Research, Winnipeg, Manitoba, Canada
| | - Hope D Anderson
- Canadian Centre for Agri-food Research in Health and Medicine, St. Boniface Hospital Research, Winnipeg, Manitoba, Canada.,College of Pharmacy, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, Canada
| | - Christopher M Anderson
- Department of Pharmacology and Therapeutics, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, Canada.,Neuroscience Research Program, Kleysen Institute for Advanced Medicine, Health Sciences Centre, Winnipeg, Manitoba, Canada
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Kardos J, Héja L, Jemnitz K, Kovács R, Palkovits M. The nature of early astroglial protection-Fast activation and signaling. Prog Neurobiol 2017; 153:86-99. [PMID: 28342942 DOI: 10.1016/j.pneurobio.2017.03.005] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Revised: 09/22/2016] [Accepted: 03/05/2017] [Indexed: 12/14/2022]
Abstract
Our present review is focusing on the uniqueness of balanced astroglial signaling. The balance of excitatory and inhibitory signaling within the CNS is mainly determined by sharp synaptic transients of excitatory glutamate (Glu) and inhibitory γ-aminobutyrate (GABA) acting on the sub-second timescale. Astroglia is involved in excitatory chemical transmission by taking up i) Glu through neurotransmitter-sodium transporters, ii) K+ released due to presynaptic action potential generation, and iii) water keeping osmotic pressure. Glu uptake-coupled Na+ influx may either ignite long-range astroglial Ca2+ transients or locally counteract over-excitation via astroglial GABA release and increased tonic inhibition. Imbalance of excitatory and inhibitory drives is associated with a number of disease conditions, including prevalent traumatic and ischaemic injuries or the emergence of epilepsy. Therefore, when addressing the potential of early therapeutic intervention, astroglial signaling functions combating progress of Glu excitotoxicity is of critical importance. We suggest, that excitotoxicity is linked primarily to over-excitation induced by the impairment of astroglial Glu uptake and/or GABA release. Within this framework, we discuss the acute alterations of Glu-cycling and metabolism and conjecture the therapeutic promise of regulation. We also confer the role played by key carrier proteins and enzymes as well as their interplay at the molecular, cellular, and organ levels. Moreover, based on our former studies, we offer potential prospect on the emerging theme of astroglial succinate sensing in course of Glu excitotoxicity.
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Affiliation(s)
- Julianna Kardos
- Functional Pharmacology Research Group, Institute of Organic Chemistry, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Hungary.
| | - László Héja
- Functional Pharmacology Research Group, Institute of Organic Chemistry, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Hungary
| | - Katalin Jemnitz
- Functional Pharmacology Research Group, Institute of Organic Chemistry, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Hungary
| | - Richárd Kovács
- Institute of Neurophysiology, Charité - Universitätsmedizin, Berlin, Germany
| | - Miklós Palkovits
- Human Brain Tissue Bank and Laboratory, Semmelweis University, Budapest, Hungary
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Kunisawa K, Kido K, Nakashima N, Matsukura T, Nabeshima T, Hiramatsu M. Betaine attenuates memory impairment after water-immersion restraint stress and is regulated by the GABAergic neuronal system in the hippocampus. Eur J Pharmacol 2017; 796:122-130. [DOI: 10.1016/j.ejphar.2016.12.007] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2016] [Revised: 12/03/2016] [Accepted: 12/05/2016] [Indexed: 02/05/2023]
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Johnson AA, Guziewicz KE, Lee CJ, Kalathur RC, Pulido JS, Marmorstein LY, Marmorstein AD. Bestrophin 1 and retinal disease. Prog Retin Eye Res 2017; 58:45-69. [PMID: 28153808 DOI: 10.1016/j.preteyeres.2017.01.006] [Citation(s) in RCA: 141] [Impact Index Per Article: 20.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2016] [Revised: 01/23/2017] [Accepted: 01/25/2017] [Indexed: 12/18/2022]
Abstract
Mutations in the gene BEST1 are causally associated with as many as five clinically distinct retinal degenerative diseases, which are collectively referred to as the "bestrophinopathies". These five associated diseases are: Best vitelliform macular dystrophy, autosomal recessive bestrophinopathy, adult-onset vitelliform macular dystrophy, autosomal dominant vitreoretinochoroidopathy, and retinitis pigmentosa. The most common of these is Best vitelliform macular dystrophy. Bestrophin 1 (Best1), the protein encoded by the gene BEST1, has been the subject of a great deal of research since it was first identified nearly two decades ago. Today we know that Best1 functions as both a pentameric anion channel and a regulator of intracellular Ca2+ signaling. Best1 is an integral membrane protein which, within the eye, is uniquely expressed in the retinal pigment epithelium where it predominantly localizes to the basolateral plasma membrane. Within the brain, Best1 expression has been documented in both glial cells and astrocytes where it functions in both tonic GABA release and glutamate transport. The crystal structure of Best1 has revealed critical information about how Best1 functions as an ion channel and how Ca2+ regulates that function. Studies using animal models have led to critical insights into the physiological roles of Best1 and advances in stem cell technology have allowed for the development of patient-derived, "disease in a dish" models. In this article we review our knowledge of Best1 and discuss prospects for near-term clinical trials to test therapies for the bestrophinopathies, a currently incurable and untreatable set of diseases.
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Affiliation(s)
- Adiv A Johnson
- Department of Ophthalmology, Mayo Clinic, Rochester, MN, USA; Nikon Instruments, Melville, NY, USA
| | - Karina E Guziewicz
- Department of Clinical Studies-Philadelphia, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - C Justin Lee
- Center for Neuroscience and Functional Connectomics, Brain Science Institute, Korea Institute of Science and Technology, Seoul, South Korea
| | - Ravi C Kalathur
- New York Structural Biology Center, New York Consortium on Membrane Protein Structure, New York, NY, USA
| | - Jose S Pulido
- Department of Ophthalmology, Mayo Clinic, Rochester, MN, USA
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Carter JM, Landin JD, Gigante ED, Rieger SP, Diaz MR, Werner DF. Inhibitors of Calcium-Activated Anion Channels Modulate Hypnotic Ethanol Responses in Adult Sprague Dawley Rats. Alcohol Clin Exp Res 2016; 40:301-8. [PMID: 26842249 DOI: 10.1111/acer.12957] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2015] [Accepted: 11/02/2015] [Indexed: 11/26/2022]
Abstract
BACKGROUND Ethanol is widely known for its depressant effects; however, the underlying neurobiological mechanisms are not clear. Calcium-activated anion channels (CAACs) contribute to extracellular chloride levels and thus may be involved in regulating inhibitory mechanisms within the central nervous system. Therefore, we hypothesized that CAACs influence ethanol behavioral sensitivity by altering CAAC expression. METHODS We assessed the role of CAACs in ethanol-induced loss of righting reflex (LORR) and locomotor activity using intracerebroventricular infusions of several nonselective CAAC blockers. CAAC expression was determined after ethanol exposure. RESULTS Ethanol-induced LORR (4.0 g/kg, intraperitoneally [i.p.]) was significantly attenuated by all 4 CAAC blockers. Blocking CAACs did not impact ethanol's low-dose (1.5 g/kg, i.p.) locomotor-impairing effects. Biochemical analysis of CAAC protein expression revealed that cortical Bestrophin1 (Best1) and Tweety1 levels were reduced as early as 30 minutes following a single ethanol injection (3.5 g/kg, intraperitoneally [i.p.]) and remained decreased 24 hours later in P2 fractions. Cortical Best1 levels were also reduced following 1.5 g/kg. However, CAAC expression was unaltered in the striatum following a single ethanol exposure. Ethanol did not affect Tweety2 levels in either brain region. CONCLUSIONS These results suggest that CAACs are a major target of ethanol in vivo, and the regulation of these channels contributes to select behavioral actions of ethanol.
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Affiliation(s)
- Jenna M Carter
- Department of Psychology, Center for Development and Behavioral Neuroscience, Binghamton University - State University of New York, Binghamton, New York
| | - Justine D Landin
- Department of Psychology, Center for Development and Behavioral Neuroscience, Binghamton University - State University of New York, Binghamton, New York
| | - Eduardo D Gigante
- Department of Psychology, Center for Development and Behavioral Neuroscience, Binghamton University - State University of New York, Binghamton, New York.,Department of Health and Human Services, Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Baltimore, Maryland
| | - Samuel P Rieger
- Department of Psychology, Center for Development and Behavioral Neuroscience, Binghamton University - State University of New York, Binghamton, New York
| | - Marvin R Diaz
- Department of Psychology, Center for Development and Behavioral Neuroscience, Binghamton University - State University of New York, Binghamton, New York
| | - David F Werner
- Department of Psychology, Center for Development and Behavioral Neuroscience, Binghamton University - State University of New York, Binghamton, New York
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Jung JY, Lee SE, Hwang EM, Lee CJ. Neuronal Expression and Cell-Type-Specific Gene-Silencing of Best1 in Thalamic Reticular Nucleus Neurons Using pSico-Red System. Exp Neurobiol 2016; 25:120-9. [PMID: 27358580 PMCID: PMC4923356 DOI: 10.5607/en.2016.25.3.120] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Revised: 05/30/2016] [Accepted: 05/31/2016] [Indexed: 12/22/2022] Open
Abstract
Assessing the cell-type expression pattern of a certain gene can be achieved by using cell-type-specific gene manipulation. Recently, cre-recombinase-dependent gene-silencing tool, pSico has become popular in neuroscientific research. However, pSico has a critical limitation that gene-silenced cell cannot be identified by fluorescence, due to an excision of the reporter gene for green fluorescence protein (GFP). To overcome this limitation, we newly developed pSico-Red, with mCherry gene as a reporter outside two loxP sites, so that red mCherry signal is detected in all transfected cells. When a cell expresses cre, GFP is excised and shRNA is enabled, resulting in disappearance of GFP. This feature of pSico-Red provides not only cell-type-specific gene-silencing but also identification of cre expressing cells. Using this system, we demonstrated for the first time the neuronal expression of the Bestrophin-1 (Best1) in thalamic reticular nucleus (TRN) and TRN-neuron-specific gene-silencing of Best1. We combined adeno-associated virus (AAV) carrying Best1-shRNA in pSico-Red vector and transgenic mouse expressing cre under the promoter of distal-less homeobox 5/6 (DLX5/6), a marker for inhibitory neurons. Firstly, we found that almost all of inhibitory neurons in TRN express Best1 by immunohistochemistry. Using pSico-Red virus, we found that 80% of infected TRN neurons were DLX5/6-cre positive but parvalbumin negative. Finally, we found that Best1 in DLX5/6-cre positive neurons were significantly reduced by Best1-shRNA. Our study demonstrates that TRN neurons strongly express Best1 and that pSico-Red is a valuable tool for cell-type-specific gene manipulation and identification of specific cell population.
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Affiliation(s)
- Jae-Young Jung
- Center for Neuroscience and Functional Connectomics, Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea.; Neuroscience Program, University of Science and Technology (UST), Daejeon 34113, Korea
| | - Seung Eun Lee
- Research Animal Resource Center, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea
| | - Eun Mi Hwang
- Center for Neuroscience and Functional Connectomics, Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea.; Neuroscience Program, University of Science and Technology (UST), Daejeon 34113, Korea
| | - C Justin Lee
- Center for Neuroscience and Functional Connectomics, Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea.; Neuroscience Program, University of Science and Technology (UST), Daejeon 34113, Korea.; KU-KIST School of Converging Science and Technology, Korea University, Seoul 02841, Korea
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42
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New Insights on Astrocyte Ion Channels: Critical for Homeostasis and Neuron-Glia Signaling. J Neurosci 2016; 35:13827-35. [PMID: 26468182 DOI: 10.1523/jneurosci.2603-15.2015] [Citation(s) in RCA: 140] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
UNLABELLED Initial biophysical studies on glial cells nearly 50 years ago identified these cells as being electrically silent. These first studies also demonstrated a large K(+) conductance, which led to the notion that glia may regulate extracellular K(+) levels homeostatically. This view has now gained critical support from the study of multiple disease models discussed herein. Dysfunction of a major astrocyte K(+) channel, Kir4.1, appears as an early pathological event underlying neuronal phenotypes in several neurodevelopmental and neurodegenerative diseases. An expanding list of other astrocyte ion channels, including the calcium-activated ion channel BEST-1, hemichannels, and two-pore domain K(+) channels, all contribute to astrocyte biology and CNS function and underpin new forms of crosstalk between neurons and glia. Once considered merely the glue that holds the brain together, it is now increasingly recognized that astrocytes contribute in several fundamental ways to neuronal function. Emerging new insights and future perspectives of this active research area are highlighted within. SIGNIFICANCE STATEMENT The critical role of astrocyte potassium channels in CNS homeostasis has been reemphasized by recent studies conducted in animal disease models. Emerging evidence also supports the signaling role mediated by astrocyte ion channels such as BEST1, hemichannels, and two-pore channels, which enable astrocytes to interact with neurons and regulate synaptic transmission and plasticity. This minisymposium highlights recent developments and future perspectives of these research areas.
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Kirischuk S, Héja L, Kardos J, Billups B. Astrocyte sodium signaling and the regulation of neurotransmission. Glia 2015; 64:1655-66. [DOI: 10.1002/glia.22943] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Accepted: 10/28/2015] [Indexed: 02/01/2023]
Affiliation(s)
- Sergei Kirischuk
- University Medical Center of the Johannes Gutenberg University Mainz, Institute of Physiology; Mainz Germany
| | - László Héja
- Institute of Organic Chemistry, Research Centre for Natural Sciences, Hungarian Academy of Sciences; Budapest Hungary
| | - Julianna Kardos
- Institute of Organic Chemistry, Research Centre for Natural Sciences, Hungarian Academy of Sciences; Budapest Hungary
| | - Brian Billups
- Eccles Institute of Neuroscience, John Curtin School of Medical Research, The Australian National University; Acton ACT Australia
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Losi G, Mariotti L, Carmignoto G. GABAergic interneuron to astrocyte signalling: a neglected form of cell communication in the brain. Philos Trans R Soc Lond B Biol Sci 2015; 369:20130609. [PMID: 25225102 DOI: 10.1098/rstb.2013.0609] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
GABAergic interneurons represent a minority of all cortical neurons and yet they efficiently control neural network activities in all brain areas. In parallel, glial cell astrocytes exert a broad control of brain tissue homeostasis and metabolism, modulate synaptic transmission and contribute to brain information processing in a dynamic interaction with neurons that is finely regulated in time and space. As most studies have focused on glutamatergic neurons and excitatory transmission, our knowledge of functional interactions between GABAergic interneurons and astrocytes is largely defective. Here, we critically discuss the currently available literature that hints at a potential relevance of this specific signalling in brain function. Astrocytes can respond to GABA through different mechanisms that include GABA receptors and transporters. GABA-activated astrocytes can, in turn, modulate local neuronal activity by releasing gliotransmitters including glutamate and ATP. In addition, astrocyte activation by different signals can modulate GABAergic neurotransmission. Full clarification of the reciprocal signalling between different GABAergic interneurons and astrocytes will improve our understanding of brain network complexity and has the potential to unveil novel therapeutic strategies for brain disorders.
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Affiliation(s)
- Gabriele Losi
- Department of Biomedical Science, Consiglio Nazionale delle Ricerche, Neuroscience Institute and University of Padova, Padova, Italy
| | - Letizia Mariotti
- Department of Biomedical Science, Consiglio Nazionale delle Ricerche, Neuroscience Institute and University of Padova, Padova, Italy
| | - Giorgio Carmignoto
- Department of Biomedical Science, Consiglio Nazionale delle Ricerche, Neuroscience Institute and University of Padova, Padova, Italy
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Abstract
We delineate perspectives for the design and discovery of antiepileptic drugs (AEDs) with fewer side effects by focusing on astroglial modulation of spatiotemporal seizure dynamics. It is now recognized that the major inhibitory neurotransmitter of the brain, γ-aminobutyric acid (GABA), can be released through the reversal of astroglial GABA transporters. Synaptic spillover and subsequent glutamate (Glu) uptake in neighboring astrocytes evoke replacement of extracellular Glu for GABA, driving neurons away from the seizure threshold. Attenuation of synaptic signaling by this negative feedback through the interplay of Glu and GABA transporters of adjacent astroglia can result in shortened seizures. By contrast, long-range activation of astroglia through gap junctions may promote recurrent seizures on the model of pharmacoresistant temporal lobe epilepsy. From their first detection to our current understanding, we identify various targets that shape both short- and long-range neuro-astroglia coupling, as these are manifest in epilepsy phenomena and in the associated research promotions of AED.
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Affiliation(s)
- Julianna Kardos
- Functional Pharmacology Research Group, Institute of Organic Chemistry, Research Centre for Natural Sciences, Hungarian Academy of Sciences, 1117 Budapest, Hungary
| | - Zsolt Szabó
- Functional Pharmacology Research Group, Institute of Organic Chemistry, Research Centre for Natural Sciences, Hungarian Academy of Sciences, 1117 Budapest, Hungary
| | - László Héja
- Functional Pharmacology Research Group, Institute of Organic Chemistry, Research Centre for Natural Sciences, Hungarian Academy of Sciences, 1117 Budapest, Hungary
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46
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Yarishkin O, Lee J, Jo S, Hwang EM, Lee CJ. Disinhibitory Action of Astrocytic GABA at the Perforant Path to Dentate Gyrus Granule Neuron Synapse Reverses to Inhibitory in Alzheimer's Disease Model. Exp Neurobiol 2015; 24:211-8. [PMID: 26412970 PMCID: PMC4580748 DOI: 10.5607/en.2015.24.3.211] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Revised: 08/25/2015] [Accepted: 08/25/2015] [Indexed: 12/11/2022] Open
Abstract
Like neurons, astrocytes produce and release GABA to influence neuronal signaling. At the perforant path to dentate gyrus granule neuron synapse, GABA from astrocyte was found to be a strong inhibitory factor, which impairs synaptic transmission, synaptic plasticity and memory in Alzheimer's disease. Although astrocytic GABA is observed in many brain regions, its physiological role has not been clearly demonstrated yet. Here, we show that astrocytic GABA exerts disinhibitory action to dentate granule neurons by targeting GABAB receptors of GABAergic interneurons in wild-type mice. This disinhibitory effect is specific to a low intensity of electrical stimulation at perforant path fibers. Inversely in Alzheimer's disease model mice, astrocytic GABA targets GABAA receptors and exerts inhibitory action by reducing release probability of glutamatergic perforant path terminals. These results suggest that astrocytic GABA differentially modulates the signaling from cortical input to dentate gyrus under physiological and pathological conditions.
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Affiliation(s)
- Oleg Yarishkin
- Center for Neuroscience and Functional Connectomics, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea
| | - Jaekwang Lee
- Center for Neuroscience and Functional Connectomics, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea
| | - Seonmi Jo
- Center for Neuroscience and Functional Connectomics, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea. ; Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea
| | - Eun Mi Hwang
- Center for Neuroscience and Functional Connectomics, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea. ; Neuroscience Program, University of Science and Technology (UST), Daejeon 34113, Korea
| | - C Justin Lee
- Center for Neuroscience and Functional Connectomics, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea. ; Neuroscience Program, University of Science and Technology (UST), Daejeon 34113, Korea. ; KU-KIST Graduate School of Converging Science and Technology, Seoul 02841, Korea
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47
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Abstract
Neuroglia, the "glue" that fills the space between neurons in the central nervous system, takes active part in nerve cell signaling. Neuroglial cells, astroglia, oligodendroglia, and microglia, are together about as numerous as neurons in the brain as a whole, and in the cerebral cortex grey matter, but the proportion varies widely among brain regions. Glial volume, however, is less than one-fifth of the tissue volume in grey matter. When stimulated by neurons or other cells, neuroglial cells release gliotransmitters by exocytosis, similar to neurotransmitter release from nerve endings, or by carrier-mediated transport or channel flux through the plasma membrane. Gliotransmitters include the common neurotransmitters glutamate and GABA, the nonstandard amino acid d-serine, the high-energy phosphate ATP, and l-lactate. The latter molecule is a "buffer" between glycolytic and oxidative metabolism as well as a signaling substance recently shown to act on specific lactate receptors in the brain. Complementing neurotransmission at a synapse, neuroglial transmission often implies diffusion of the transmitter over a longer distance and concurs with the concept of volume transmission. Transmission from glia modulates synaptic neurotransmission based on energetic and other local conditions in a volume of tissue surrounding the individual synapse. Neuroglial transmission appears to contribute significantly to brain functions such as memory, as well as to prevalent neuropathologies.
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Affiliation(s)
- Vidar Gundersen
- SN-Lab, Division of Anatomy, Department of Molecular Medicine, Institute of Basic Medical Sciences, and CMBN/SERTA/Healthy Brain Ageing Centre, University of Oslo, Oslo, Norway; Department of Neurology, Oslo University Hospital-Rikshospitalet, Oslo, Norway; Center for Healthy Aging, Department of Neuroscience and Pharmacology, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark; and Brain and Muscle Energy Group, Department of Oral Biology and Division of Anatomy, Department of Molecular Medicine, University of Oslo, Oslo, Norway
| | - Jon Storm-Mathisen
- SN-Lab, Division of Anatomy, Department of Molecular Medicine, Institute of Basic Medical Sciences, and CMBN/SERTA/Healthy Brain Ageing Centre, University of Oslo, Oslo, Norway; Department of Neurology, Oslo University Hospital-Rikshospitalet, Oslo, Norway; Center for Healthy Aging, Department of Neuroscience and Pharmacology, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark; and Brain and Muscle Energy Group, Department of Oral Biology and Division of Anatomy, Department of Molecular Medicine, University of Oslo, Oslo, Norway
| | - Linda Hildegard Bergersen
- SN-Lab, Division of Anatomy, Department of Molecular Medicine, Institute of Basic Medical Sciences, and CMBN/SERTA/Healthy Brain Ageing Centre, University of Oslo, Oslo, Norway; Department of Neurology, Oslo University Hospital-Rikshospitalet, Oslo, Norway; Center for Healthy Aging, Department of Neuroscience and Pharmacology, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark; and Brain and Muscle Energy Group, Department of Oral Biology and Division of Anatomy, Department of Molecular Medicine, University of Oslo, Oslo, Norway
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48
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De Zeeuw CI, Hoogland TM. Reappraisal of Bergmann glial cells as modulators of cerebellar circuit function. Front Cell Neurosci 2015; 9:246. [PMID: 26190972 PMCID: PMC4488625 DOI: 10.3389/fncel.2015.00246] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2015] [Accepted: 06/17/2015] [Indexed: 11/13/2022] Open
Abstract
Just as there is a huge morphological and functional diversity of neuron types specialized for specific aspects of information processing in the brain, astrocytes have equally distinct morphologies and functions that aid optimal functioning of the circuits in which they are embedded. One type of astrocyte, the Bergmann glial cell (BG) of the cerebellum, is a prime example of a highly diversified astrocyte type, the architecture of which is adapted to the cerebellar circuit and facilitates an impressive range of functions that optimize information processing in the adult brain. In this review we expand on the function of the BG in the cerebellum to highlight the importance of astrocytes not only in housekeeping functions, but also in contributing to plasticity and information processing in the cerebellum.
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Affiliation(s)
- Chris I De Zeeuw
- Cerebellar Coordination and Cognition, Netherlands Institute for Neuroscience Amsterdam, Netherlands ; Department of Neuroscience, Erasmus MC Rotterdam, Netherlands
| | - Tycho M Hoogland
- Cerebellar Coordination and Cognition, Netherlands Institute for Neuroscience Amsterdam, Netherlands ; Department of Neuroscience, Erasmus MC Rotterdam, Netherlands
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49
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Abstract
Gamma-amino butyric acid (GABA) is the major inhibitory neurotransmitter that is known to be synthesized and released from GABAergic neurons in the brain. However, recent studies have shown that not only neurons but also astrocytes contain a considerable amount of GABA that can be released and activate GABA receptors in neighboring neurons. These exciting new findings for glial GABA raise further interesting questions about the source of GABA, its mechanism of release and regulation and the functional role of glial GABA. In this review, we highlight recent studies that identify the presence and release of GABA in glial cells, we show several proposed potential pathways for accumulation and modulation of glial intracellular and extracellular GABA content, and finally we discuss functional roles for glial GABA in the brain.
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Affiliation(s)
- Bo-Eun Yoon
- Department of Nanobiomedical Science, Dankook University Chungnam, South Korea
| | - C Justin Lee
- WCI Center for Functional Connectomics, Korea Institute of Science and Technology (KIST) Seoul, South Korea ; Center for Neural Science and Center for Functional Connectomics, Korea Institute of Science and Technology (KIST) Seoul, South Korea
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50
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Berdyyeva T, Otte S, Aluisio L, Ziv Y, Burns LD, Dugovic C, Yun S, Ghosh KK, Schnitzer MJ, Lovenberg T, Bonaventure P. Zolpidem reduces hippocampal neuronal activity in freely behaving mice: a large scale calcium imaging study with miniaturized fluorescence microscope. PLoS One 2014; 9:e112068. [PMID: 25372144 PMCID: PMC4221229 DOI: 10.1371/journal.pone.0112068] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2014] [Accepted: 10/07/2014] [Indexed: 11/18/2022] Open
Abstract
Therapeutic drugs for cognitive and psychiatric disorders are often characterized by their molecular mechanism of action. Here we demonstrate a new approach to elucidate drug action on large-scale neuronal activity by tracking somatic calcium dynamics in hundreds of CA1 hippocampal neurons of pharmacologically manipulated behaving mice. We used an adeno-associated viral vector to express the calcium sensor GCaMP3 in CA1 pyramidal cells under control of the CaMKII promoter and a miniaturized microscope to observe cellular dynamics. We visualized these dynamics with and without a systemic administration of Zolpidem, a GABAA agonist that is the most commonly prescribed drug for the treatment of insomnia in the United States. Despite growing concerns about the potential adverse effects of Zolpidem on memory and cognition, it remained unclear whether Zolpidem alters neuronal activity in the hippocampus, a brain area critical for cognition and memory. Zolpidem, when delivered at a dose known to induce and prolong sleep, strongly suppressed CA1 calcium signaling. The rate of calcium transients after Zolpidem administration was significantly lower compared to vehicle treatment. To factor out the contribution of changes in locomotor or physiological conditions following Zolpidem treatment, we compared the cellular activity across comparable epochs matched by locomotor and physiological assessments. This analysis revealed significantly depressive effects of Zolpidem regardless of the animal's state. Individual hippocampal CA1 pyramidal cells differed in their responses to Zolpidem with the majority (∼ 65%) significantly decreasing the rate of calcium transients, and a small subset (3%) showing an unexpected and significant increase. By linking molecular mechanisms with the dynamics of neural circuitry and behavioral states, this approach has the potential to contribute substantially to the development of new therapeutics for the treatment of CNS disorders.
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Affiliation(s)
- Tamara Berdyyeva
- Janssen Research & Development, LLC, San Diego, California, United States of America
| | - Stephani Otte
- Inscopix, Palo Alto, California, United States of America
| | - Leah Aluisio
- Janssen Research & Development, LLC, San Diego, California, United States of America
| | - Yaniv Ziv
- Inscopix, Palo Alto, California, United States of America
| | | | - Christine Dugovic
- Janssen Research & Development, LLC, San Diego, California, United States of America
| | - Sujin Yun
- Janssen Research & Development, LLC, San Diego, California, United States of America
| | - Kunal K. Ghosh
- Inscopix, Palo Alto, California, United States of America
| | | | - Timothy Lovenberg
- Janssen Research & Development, LLC, San Diego, California, United States of America
| | - Pascal Bonaventure
- Janssen Research & Development, LLC, San Diego, California, United States of America
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