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Ollivier M, Soto JS, Linker KE, Moye SL, Jami-Alahmadi Y, Jones AE, Divakaruni AS, Kawaguchi R, Wohlschlegel JA, Khakh BS. Crym-positive striatal astrocytes gate perseverative behaviour. Nature 2024; 627:358-366. [PMID: 38418885 PMCID: PMC10937394 DOI: 10.1038/s41586-024-07138-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2023] [Accepted: 01/31/2024] [Indexed: 03/02/2024]
Abstract
Astrocytes are heterogeneous glial cells of the central nervous system1-3. However, the physiological relevance of astrocyte diversity for neural circuits and behaviour remains unclear. Here we show that a specific population of astrocytes in the central striatum expresses μ-crystallin (encoded by Crym in mice and CRYM in humans) that is associated with several human diseases, including neuropsychiatric disorders4-7. In adult mice, reducing the levels of μ-crystallin in striatal astrocytes through CRISPR-Cas9-mediated knockout of Crym resulted in perseverative behaviours, increased fast synaptic excitation in medium spiny neurons and dysfunctional excitatory-inhibitory synaptic balance. Increased perseveration stemmed from the loss of astrocyte-gated control of neurotransmitter release from presynaptic terminals of orbitofrontal cortex-striatum projections. We found that perseveration could be remedied using presynaptic inhibitory chemogenetics8, and that this treatment also corrected the synaptic deficits. Together, our findings reveal converging molecular, synaptic, circuit and behavioural mechanisms by which a molecularly defined and allocated population of striatal astrocytes gates perseveration phenotypes that accompany neuropsychiatric disorders9-12. Our data show that Crym-positive striatal astrocytes have key biological functions within the central nervous system, and uncover astrocyte-neuron interaction mechanisms that could be targeted in treatments for perseveration.
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Affiliation(s)
- Matthias Ollivier
- Department of Physiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, USA
| | - Joselyn S Soto
- Department of Physiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, USA
| | - Kay E Linker
- Department of Physiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, USA
| | - Stefanie L Moye
- Department of Physiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, USA
| | - Yasaman Jami-Alahmadi
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, USA
| | - Anthony E Jones
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, USA
| | - Ajit S Divakaruni
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, USA
| | - Riki Kawaguchi
- Center for Neurobehavioral Genetics, Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, USA
| | - James A Wohlschlegel
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, USA
| | - Baljit S Khakh
- Department of Physiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, USA.
- Department of Neurobiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, USA.
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2
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Benarroch E. What Is the Role of the "GABA Tone" in Normal and Pathological Conditions? Neurology 2024; 102:e209152. [PMID: 38252909 DOI: 10.1212/wnl.0000000000209152] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Accepted: 11/28/2023] [Indexed: 01/24/2024] Open
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3
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Xu C, Chen S, Chen X, Ho KH, Park C, Yoo H, Lee SH, Park H. Altered exocytosis of inhibitory synaptic vesicles at single presynaptic terminals of cultured striatal neurons in a knock-in mouse model of Huntington's disease. Front Mol Neurosci 2023; 16:1175522. [PMID: 37664244 PMCID: PMC10470468 DOI: 10.3389/fnmol.2023.1175522] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Accepted: 07/24/2023] [Indexed: 09/05/2023] Open
Abstract
Huntington's disease (HD) is a progressive dominantly inherited neurodegenerative disease caused by the expansion of a cytosine-adenine-guanine (CAG) trinucleotide repeat in the huntingtin gene, which encodes the mutant huntingtin protein containing an expanded polyglutamine tract. One of neuropathologic hallmarks of HD is selective degeneration in the striatum. Mechanisms underlying selective neurodegeneration in the striatum of HD remain elusive. Neurodegeneration is suggested to be preceded by abnormal synaptic transmission at the early stage of HD. However, how mutant huntingtin protein affects synaptic vesicle exocytosis at single presynaptic terminals of HD striatal neurons is poorly understood. Here, we measured synaptic vesicle exocytosis at single presynaptic terminals of cultured striatal neurons (mainly inhibitory neurons) in a knock-in mouse model of HD (zQ175) during electrical field stimulation using real-time imaging of FM 1-43 (a lipophilic dye). We found a significant decrease in bouton density and exocytosis of synaptic vesicles at single presynaptic terminals in cultured striatal neurons. Real-time imaging of VGAT-CypHer5E (a pH sensitive dye conjugated to an antibody against vesicular GABA transporter (VGAT)) for inhibitory synaptic vesicles revealed a reduction in bouton density and exocytosis of inhibitory synaptic vesicles at single presynaptic terminals of HD striatal neurons. Thus, our results suggest that the mutant huntingtin protein decreases bouton density and exocytosis of inhibitory synaptic vesicles at single presynaptic terminals of striatal neurons, causing impaired inhibitory synaptic transmission, eventually leading to the neurodegeneration in the striatum of HD.
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Affiliation(s)
- Chen Xu
- Division of Life Science, The Hong Kong University of Science and Technology, Kowloon, Hong Kong SAR, China
| | - Sidong Chen
- Division of Life Science, The Hong Kong University of Science and Technology, Kowloon, Hong Kong SAR, China
| | - Xingxiang Chen
- Division of Life Science, The Hong Kong University of Science and Technology, Kowloon, Hong Kong SAR, China
| | - Ka Hei Ho
- Division of Life Science, The Hong Kong University of Science and Technology, Kowloon, Hong Kong SAR, China
| | - Chungwon Park
- Division of Life Science, The Hong Kong University of Science and Technology, Kowloon, Hong Kong SAR, China
- Hong Kong Center for Construction Robotics (InnoHK-HKCRC), Hong Kong Science Park, Sha Tin, Hong Kong SAR, China
| | - Hanna Yoo
- Division of Life Science, The Hong Kong University of Science and Technology, Kowloon, Hong Kong SAR, China
| | - Suk-Ho Lee
- Department of Physiology, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Hyokeun Park
- Division of Life Science, The Hong Kong University of Science and Technology, Kowloon, Hong Kong SAR, China
- Department of Physics, The Hong Kong University of Science and Technology, Kowloon, Hong Kong SAR, China
- State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Kowloon, Hong Kong SAR, China
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4
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Khakh BS, Goldman SA. Astrocytic contributions to Huntington's disease pathophysiology. Ann N Y Acad Sci 2023; 1522:42-59. [PMID: 36864567 PMCID: PMC10145027 DOI: 10.1111/nyas.14977] [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] [Indexed: 03/04/2023]
Abstract
Huntington's disease (HD) is a fatal, monogenic, autosomal dominant neurodegenerative disease caused by a polyglutamine-encoding CAG expansion in the huntingtin (HTT) gene that results in mutant huntingtin proteins (mHTT) in cells throughout the body. Although large parts of the central nervous system (CNS) are affected, the striatum is especially vulnerable and undergoes marked atrophy. Astrocytes are abundant within the striatum and contain mHTT in HD, as well as in mouse models of the disease. We focus on striatal astrocytes and summarize how they participate in, and contribute to, molecular pathophysiology and disease-related phenotypes in HD model mice. Where possible, reference is made to pertinent astrocyte alterations in human HD. Astrocytic dysfunctions related to cellular morphology, extracellular ion and neurotransmitter homeostasis, and metabolic support all accompany the development and progression of HD, in both transgenic mouse and human cellular and chimeric models of HD. These findings reveal the potential for the therapeutic targeting of astrocytes so as to restore synaptic as well as tissue homeostasis in HD. Elucidation of the mechanisms by which astrocytes contribute to HD pathogenesis may inform a broader understanding of the role of glial pathology in neurodegenerative disorders and, by so doing, enable new strategies of glial-directed therapeutics.
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Affiliation(s)
- Baljit S. Khakh
- Department of Physiology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, USA
- Department of Neurobiology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, USA
| | - Steven A. Goldman
- Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, New York, USA
- Center for Translational Neuromedicine, University of Copenhagen Faculty of Health and Medical Sciences, Copenhagen, Denmark
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5
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Lange J, Gillham O, Flower M, Ging H, Eaton S, Kapadia S, Neueder A, Duchen MR, Ferretti P, Tabrizi SJ. PolyQ length-dependent metabolic alterations and DNA damage drive human astrocyte dysfunction in Huntington’s disease. Prog Neurobiol 2023; 225:102448. [PMID: 37023937 DOI: 10.1016/j.pneurobio.2023.102448] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2022] [Revised: 02/03/2023] [Accepted: 03/24/2023] [Indexed: 04/07/2023]
Abstract
Huntington's Disease (HD) is a neurodegenerative disease caused by a polyglutamine (polyQ) expansion in the Huntingtin gene. Astrocyte dysfunction is known to contribute to HD pathology, however our understanding of the molecular pathways involved is limited. Transcriptomic analysis of patient-derived PSC (pluripotent stem cells) astrocyte lines revealed that astrocytes with similar polyQ lengths shared a large number of differentially expressed genes (DEGs). Notably, weighted correlation network analysis (WGCNA) modules from iPSC derived astrocytes showed significant overlap with WGCNA modules from two post-mortem HD cohorts. Further experiments revealed two key elements of astrocyte dysfunction. Firstly, expression of genes linked to astrocyte reactivity, as well as metabolic changes were polyQ length-dependent. Hypermetabolism was observed in shorter polyQ length astrocytes compared to controls, whereas metabolic activity and release of metabolites were significantly reduced in astrocytes with increasing polyQ lengths. Secondly, all HD astrocytes showed increased DNA damage, DNA damage response and upregulation of mismatch repair genes and proteins. Together our study shows for the first time polyQ-dependent phenotypes and functional changes in HD astrocytes providing evidence that increased DNA damage and DNA damage response could contribute to HD astrocyte dysfunction.
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Asgharpour-Masouleh N, Rezayof A, Alijanpour S, Delphi L. Pharmacological activation of mediodorsal thalamic GABA-A receptors modulates morphine/cetirizine-induced changes in the prefrontal cortical GFAP expression in a rat model of neuropathic pain. Behav Brain Res 2023; 438:114213. [PMID: 36372242 DOI: 10.1016/j.bbr.2022.114213] [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: 06/06/2022] [Revised: 10/21/2022] [Accepted: 11/08/2022] [Indexed: 11/13/2022]
Abstract
The present study investigated the involvement of mediodorsal thalamic (MD) GABA-A receptors in cetirizine/morphine-induced anti-allodynia using a rat model of neuropathic pain. To assess the importance of the prefrontal cortex (PFC) for chronic pain processing, its expression level changes of glial fibrillary acidic protein (GFAP) were measured following drug treatments. Each animal was subjected to chronic constriction of the sciatic nerve surgery simultaneously with the MD cannulation under stereotaxic surgery. The results showed that the administration of morphine (3-5 mg/kg) or cetirizine (1-3 mg/kg) produced significant analgesia in neuropathic rats. Systemic administration of cetirizine (2.5 and 3 mg/kg) potentiated the analgesic response to a low and intolerance dose of morphine (3 mg/kg). Intra-MD microinjection of muscimol, a selective GABA-A receptor agonist (0.005-0.01 μg/rat), increased the cetirizine/morphine-induced anti-allodynia, while muscimol by itself did not affect neuropathic pain. The neuropathic pain was associated with the increased PFC expression level of GFAP, suggesting the impact of chronic pain on PFC glial management. Interestingly, the anti-allodynia was associated with a decrease in the PFC expression level of GFAP under the drugs' co-administration. Thus, cetirizine has a significant potentiating effect on morphine response in neuropathic pain via interacting with the MD GABA-A receptors. It seems that neuropathic pain affects the prefrontal cortex GFAP signaling pathway. In clinical studies, these findings can be considered to create a combination therapy with low doses of GABA-A receptor agonist plus cetirizine and morphine to manage neuropathic pain.
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Affiliation(s)
| | - Ameneh Rezayof
- Department of Animal Biology, School of Biology, College of Science, University of Tehran, Tehran, Iran.
| | - Sakineh Alijanpour
- Department of Biology, Faculty of Science, Gonbad Kavous University, Gonbad Kavous, Iran
| | - Ladan Delphi
- Department of Animal Biology, School of Biology, College of Science, University of Tehran, Tehran, Iran
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7
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Abjean L, Ben Haim L, Riquelme-Perez M, Gipchtein P, Derbois C, Palomares MA, Petit F, Hérard AS, Gaillard MC, Guillermier M, Gaudin-Guérif M, Aurégan G, Sagar N, Héry C, Dufour N, Robil N, Kabani M, Melki R, De la Grange P, Bemelmans AP, Bonvento G, Deleuze JF, Hantraye P, Flament J, Bonnet E, Brohard S, Olaso R, Brouillet E, Carrillo-de Sauvage MA, Escartin C. Reactive astrocytes promote proteostasis in Huntington's disease through the JAK2-STAT3 pathway. Brain 2023; 146:149-166. [PMID: 35298632 DOI: 10.1093/brain/awac068] [Citation(s) in RCA: 24] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Revised: 01/13/2022] [Accepted: 01/24/2022] [Indexed: 01/11/2023] Open
Abstract
Huntington's disease is a fatal neurodegenerative disease characterized by striatal neurodegeneration, aggregation of mutant Huntingtin and the presence of reactive astrocytes. Astrocytes are important partners for neurons and engage in a specific reactive response in Huntington's disease that involves morphological, molecular and functional changes. How reactive astrocytes contribute to Huntington's disease is still an open question, especially because their reactive state is poorly reproduced in experimental mouse models. Here, we show that the JAK2-STAT3 pathway, a central cascade controlling astrocyte reactive response, is activated in the putamen of Huntington's disease patients. Selective activation of this cascade in astrocytes through viral gene transfer reduces the number and size of mutant Huntingtin aggregates in neurons and improves neuronal defects in two complementary mouse models of Huntington's disease. It also reduces striatal atrophy and increases glutamate levels, two central clinical outcomes measured by non-invasive magnetic resonance imaging. Moreover, astrocyte-specific transcriptomic analysis shows that activation of the JAK2-STAT3 pathway in astrocytes coordinates a transcriptional program that increases their intrinsic proteolytic capacity, through the lysosomal and ubiquitin-proteasome degradation systems. This pathway also enhances their production and exosomal release of the co-chaperone DNAJB1, which contributes to mutant Huntingtin clearance in neurons. Together, our results show that the JAK2-STAT3 pathway controls a beneficial proteostasis response in reactive astrocytes in Huntington's disease, which involves bi-directional signalling with neurons to reduce mutant Huntingtin aggregation, eventually improving disease outcomes.
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Affiliation(s)
- Laurene Abjean
- Université Paris-Saclay, Commissariat à l'Energie Atomique et aux Energies Alternatives, Centre National de la Recherche Scientifique, MIRCen, Laboratoire des Maladies Neurodégénératives, 92265 Fontenay-aux-Roses, France
| | - Lucile Ben Haim
- Université Paris-Saclay, Commissariat à l'Energie Atomique et aux Energies Alternatives, Centre National de la Recherche Scientifique, MIRCen, Laboratoire des Maladies Neurodégénératives, 92265 Fontenay-aux-Roses, France
| | - Miriam Riquelme-Perez
- Université Paris-Saclay, Commissariat à l'Energie Atomique et aux Energies Alternatives, Centre National de la Recherche Scientifique, MIRCen, Laboratoire des Maladies Neurodégénératives, 92265 Fontenay-aux-Roses, France.,Université Paris-Saclay, Commissariat à l'Energie Atomique et aux Energies Alternatives, Centre National de Recherche en Génomique Humaine, 91057 Evry, France
| | - Pauline Gipchtein
- Université Paris-Saclay, Commissariat à l'Energie Atomique et aux Energies Alternatives, Centre National de la Recherche Scientifique, MIRCen, Laboratoire des Maladies Neurodégénératives, 92265 Fontenay-aux-Roses, France
| | - Céline Derbois
- Université Paris-Saclay, Commissariat à l'Energie Atomique et aux Energies Alternatives, Centre National de Recherche en Génomique Humaine, 91057 Evry, France
| | - Marie-Ange Palomares
- Université Paris-Saclay, Commissariat à l'Energie Atomique et aux Energies Alternatives, Centre National de Recherche en Génomique Humaine, 91057 Evry, France
| | - Fanny Petit
- Université Paris-Saclay, Commissariat à l'Energie Atomique et aux Energies Alternatives, Centre National de la Recherche Scientifique, MIRCen, Laboratoire des Maladies Neurodégénératives, 92265 Fontenay-aux-Roses, France
| | - Anne-Sophie Hérard
- Université Paris-Saclay, Commissariat à l'Energie Atomique et aux Energies Alternatives, Centre National de la Recherche Scientifique, MIRCen, Laboratoire des Maladies Neurodégénératives, 92265 Fontenay-aux-Roses, France
| | - Marie-Claude Gaillard
- Université Paris-Saclay, Commissariat à l'Energie Atomique et aux Energies Alternatives, Centre National de la Recherche Scientifique, MIRCen, Laboratoire des Maladies Neurodégénératives, 92265 Fontenay-aux-Roses, France
| | - Martine Guillermier
- Université Paris-Saclay, Commissariat à l'Energie Atomique et aux Energies Alternatives, Centre National de la Recherche Scientifique, MIRCen, Laboratoire des Maladies Neurodégénératives, 92265 Fontenay-aux-Roses, France
| | - Mylène Gaudin-Guérif
- Université Paris-Saclay, Commissariat à l'Energie Atomique et aux Energies Alternatives, Centre National de la Recherche Scientifique, MIRCen, Laboratoire des Maladies Neurodégénératives, 92265 Fontenay-aux-Roses, France
| | - Gwennaëlle Aurégan
- Université Paris-Saclay, Commissariat à l'Energie Atomique et aux Energies Alternatives, Centre National de la Recherche Scientifique, MIRCen, Laboratoire des Maladies Neurodégénératives, 92265 Fontenay-aux-Roses, France
| | - Nisrine Sagar
- Université Paris-Saclay, Commissariat à l'Energie Atomique et aux Energies Alternatives, Centre National de la Recherche Scientifique, MIRCen, Laboratoire des Maladies Neurodégénératives, 92265 Fontenay-aux-Roses, France
| | - Cameron Héry
- Université Paris-Saclay, Commissariat à l'Energie Atomique et aux Energies Alternatives, Centre National de la Recherche Scientifique, MIRCen, Laboratoire des Maladies Neurodégénératives, 92265 Fontenay-aux-Roses, France
| | - Noëlle Dufour
- Université Paris-Saclay, Commissariat à l'Energie Atomique et aux Energies Alternatives, Centre National de la Recherche Scientifique, MIRCen, Laboratoire des Maladies Neurodégénératives, 92265 Fontenay-aux-Roses, France
| | | | - Mehdi Kabani
- Université Paris-Saclay, Commissariat à l'Energie Atomique et aux Energies Alternatives, Centre National de la Recherche Scientifique, MIRCen, Laboratoire des Maladies Neurodégénératives, 92265 Fontenay-aux-Roses, France
| | - Ronald Melki
- Université Paris-Saclay, Commissariat à l'Energie Atomique et aux Energies Alternatives, Centre National de la Recherche Scientifique, MIRCen, Laboratoire des Maladies Neurodégénératives, 92265 Fontenay-aux-Roses, France
| | | | - Alexis P Bemelmans
- Université Paris-Saclay, Commissariat à l'Energie Atomique et aux Energies Alternatives, Centre National de la Recherche Scientifique, MIRCen, Laboratoire des Maladies Neurodégénératives, 92265 Fontenay-aux-Roses, France
| | - Gilles Bonvento
- Université Paris-Saclay, Commissariat à l'Energie Atomique et aux Energies Alternatives, Centre National de la Recherche Scientifique, MIRCen, Laboratoire des Maladies Neurodégénératives, 92265 Fontenay-aux-Roses, France
| | - Jean-François Deleuze
- Université Paris-Saclay, Commissariat à l'Energie Atomique et aux Energies Alternatives, Centre National de Recherche en Génomique Humaine, 91057 Evry, France
| | - Philippe Hantraye
- Université Paris-Saclay, Commissariat à l'Energie Atomique et aux Energies Alternatives, Centre National de la Recherche Scientifique, MIRCen, Laboratoire des Maladies Neurodégénératives, 92265 Fontenay-aux-Roses, France
| | - Julien Flament
- Université Paris-Saclay, Commissariat à l'Energie Atomique et aux Energies Alternatives, Centre National de la Recherche Scientifique, MIRCen, Laboratoire des Maladies Neurodégénératives, 92265 Fontenay-aux-Roses, France
| | - Eric Bonnet
- Université Paris-Saclay, Commissariat à l'Energie Atomique et aux Energies Alternatives, Centre National de Recherche en Génomique Humaine, 91057 Evry, France
| | - Solène Brohard
- Université Paris-Saclay, Commissariat à l'Energie Atomique et aux Energies Alternatives, Centre National de Recherche en Génomique Humaine, 91057 Evry, France
| | - Robert Olaso
- Université Paris-Saclay, Commissariat à l'Energie Atomique et aux Energies Alternatives, Centre National de Recherche en Génomique Humaine, 91057 Evry, France
| | - Emmanuel Brouillet
- Université Paris-Saclay, Commissariat à l'Energie Atomique et aux Energies Alternatives, Centre National de la Recherche Scientifique, MIRCen, Laboratoire des Maladies Neurodégénératives, 92265 Fontenay-aux-Roses, France
| | - Maria-Angeles Carrillo-de Sauvage
- Université Paris-Saclay, Commissariat à l'Energie Atomique et aux Energies Alternatives, Centre National de la Recherche Scientifique, MIRCen, Laboratoire des Maladies Neurodégénératives, 92265 Fontenay-aux-Roses, France
| | - Carole Escartin
- Université Paris-Saclay, Commissariat à l'Energie Atomique et aux Energies Alternatives, Centre National de la Recherche Scientifique, MIRCen, Laboratoire des Maladies Neurodégénératives, 92265 Fontenay-aux-Roses, France
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8
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Kruyer A, Kalivas PW, Scofield MD. Astrocyte regulation of synaptic signaling in psychiatric disorders. Neuropsychopharmacology 2023; 48:21-36. [PMID: 35577914 PMCID: PMC9700696 DOI: 10.1038/s41386-022-01338-w] [Citation(s) in RCA: 21] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/05/2022] [Revised: 04/27/2022] [Accepted: 05/01/2022] [Indexed: 02/07/2023]
Abstract
Over the last 15 years, the field of neuroscience has evolved toward recognizing the critical role of astroglia in shaping neuronal synaptic activity and along with the pre- and postsynapse is now considered an equal partner in tripartite synaptic transmission and plasticity. The relative youth of this recognition and a corresponding deficit in reagents and technologies for quantifying and manipulating astroglia relative to neurons continues to hamper advances in understanding tripartite synaptic physiology. Nonetheless, substantial advances have been made and are reviewed herein. We review the role of astroglia in synaptic function and regulation of behavior with an eye on how tripartite synapses figure into brain pathologies underlying behavioral impairments in psychiatric disorders, both from the perspective of measures in postmortem human brains and more subtle influences on tripartite synaptic regulation of behavior in animal models of psychiatric symptoms. Our goal is to provide the reader a well-referenced state-of-the-art understanding of current knowledge and predict what we may discover with deeper investigation of tripartite synapses using reagents and technologies not yet available.
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Affiliation(s)
- Anna Kruyer
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC, USA
| | - Peter W Kalivas
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC, USA.
- Ralph H. Johnson Veterans Affairs Medical Center, Charleston, SC, USA.
| | - Michael D Scofield
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC, USA.
- Department of Anesthesia & Perioperative Medicine, Medical University of South Carolina, Charleston, SC, USA.
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9
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Bhatt M, Gauthier-Manuel L, Lazzarin E, Zerlotti R, Ziegler C, Bazzone A, Stockner T, Bossi E. A comparative review on the well-studied GAT1 and the understudied BGT-1 in the brain. Front Physiol 2023; 14:1145973. [PMID: 37123280 PMCID: PMC10137170 DOI: 10.3389/fphys.2023.1145973] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Accepted: 03/30/2023] [Indexed: 05/02/2023] Open
Abstract
γ-aminobutyric acid (GABA) is the primary inhibitory neurotransmitter in the central nervous system (CNS). Its homeostasis is maintained by neuronal and glial GABA transporters (GATs). The four GATs identified in humans are GAT1 (SLC6A1), GAT2 (SLC6A13), GAT3 (SLC6A11), and betaine/GABA transporter-1 BGT-1 (SLC6A12) which are all members of the solute carrier 6 (SLC6) family of sodium-dependent transporters. While GAT1 has been investigated extensively, the other GABA transporters are less studied and their role in CNS is not clearly defined. Altered GABAergic neurotransmission is involved in different diseases, but the importance of the different transporters remained understudied and limits drug targeting. In this review, the well-studied GABA transporter GAT1 is compared with the less-studied BGT-1 with the aim to leverage the knowledge on GAT1 to shed new light on the open questions concerning BGT-1. The most recent knowledge on transporter structure, functions, expression, and localization is discussed along with their specific role as drug targets for neurological and neurodegenerative disorders. We review and discuss data on the binding sites for Na+, Cl-, substrates, and inhibitors by building on the recent cryo-EM structure of GAT1 to highlight specific molecular determinants of transporter functions. The role of the two proteins in GABA homeostasis is investigated by looking at the transport coupling mechanism, as well as structural and kinetic transport models. Furthermore, we review information on selective inhibitors together with the pharmacophore hypothesis of transporter substrates.
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Affiliation(s)
- Manan Bhatt
- Department of Biotechnology and Life Sciences, University of Insubria, Varese, Italy
- Centre for Neuroscience—University of Insubria, Varese, Italy
| | - Laure Gauthier-Manuel
- Department of Biophysics II/Structural Biology, University of Regensburg, Regensburg, Germany
| | - Erika Lazzarin
- Center for Physiology and Pharmacology, Institute of Pharmacology, Medical University of Vienna, Waehringerstr, Vienna
| | - Rocco Zerlotti
- Department of Biophysics II/Structural Biology, University of Regensburg, Regensburg, Germany
- Nanion Technologies GmbH, Munich, Germany
| | - Christine Ziegler
- Department of Biophysics II/Structural Biology, University of Regensburg, Regensburg, Germany
| | | | - Thomas Stockner
- Center for Physiology and Pharmacology, Institute of Pharmacology, Medical University of Vienna, Waehringerstr, Vienna
- *Correspondence: Thomas Stockner, ; Elena Bossi,
| | - Elena Bossi
- Department of Biotechnology and Life Sciences, University of Insubria, Varese, Italy
- Centre for Neuroscience—University of Insubria, Varese, Italy
- *Correspondence: Thomas Stockner, ; Elena Bossi,
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10
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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: 13] [Impact Index Per Article: 6.5] [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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11
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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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12
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Liu J, Feng X, Wang Y, Xia X, Zheng JC. Astrocytes: GABAceptive and GABAergic Cells in the Brain. Front Cell Neurosci 2022; 16:892497. [PMID: 35755777 PMCID: PMC9231434 DOI: 10.3389/fncel.2022.892497] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Accepted: 05/17/2022] [Indexed: 12/14/2022] Open
Abstract
Astrocytes, the most numerous glial cells in the brain, play an important role in preserving normal neural functions and mediating the pathogenesis of neurological disorders. Recent studies have shown that astrocytes are GABAceptive and GABAergic astrocytes express GABAA receptors, GABAB receptors, and GABA transporter proteins to capture and internalize GABA. GABAceptive astrocytes thus influence both inhibitory and excitatory neurotransmission by controlling the levels of extracellular GABA. Furthermore, astrocytes synthesize and release GABA to directly regulate brain functions. In this review, we highlight recent research progresses that support astrocytes as GABAceptive and GABAergic cells. We also summarize the roles of GABAceptive and GABAergic astrocytes that serve as an inhibitory node in the intercellular communication in the brain. Besides, we discuss future directions for further expanding our knowledge on the GABAceptive and GABAergic astrocyte signaling.
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Affiliation(s)
- Jianhui Liu
- Department of Anesthesiology, Tongji Hospital affiliated to Tongji University School of Medicine, Shanghai, China
| | - Xuanran Feng
- Department of Anesthesiology, Tongji Hospital affiliated to Tongji University School of Medicine, Shanghai, China
| | - Yi Wang
- Translational Research Center, Shanghai Yangzhi Rehabilitation Hospital affiliated to Tongji University School of Medicine, Shanghai, China
| | - Xiaohuan Xia
- Department of Anesthesiology, Tongji Hospital affiliated to Tongji University School of Medicine, Shanghai, China.,Center for Translational Neurodegeneration and Regenerative Therapy, Tongji Hospital affiliated to Tongji University School of Medicine, Shanghai, China.,Shanghai Frontiers Science Center of Nanocatalytic Medicine, Shanghai, China.,Translational Research Institute of Brain and Brain-Like Intelligence, Shanghai Fourth People's Hospital affiliated to Tongji University School of Medicine, Shanghai, China
| | - Jialin C Zheng
- Department of Anesthesiology, Tongji Hospital affiliated to Tongji University School of Medicine, Shanghai, China.,Center for Translational Neurodegeneration and Regenerative Therapy, Tongji Hospital affiliated to Tongji University School of Medicine, Shanghai, China.,Shanghai Frontiers Science Center of Nanocatalytic Medicine, Shanghai, China.,Translational Research Institute of Brain and Brain-Like Intelligence, Shanghai Fourth People's Hospital affiliated to Tongji University School of Medicine, Shanghai, China.,Collaborative Innovation Center for Brain Science, Tongji University, Shanghai, China
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13
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Sun J, Zheng Y, Chen Z, Wang Y. The role of Na + -K + -ATPase in the epileptic brain. CNS Neurosci Ther 2022; 28:1294-1302. [PMID: 35751846 PMCID: PMC9344081 DOI: 10.1111/cns.13893] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2022] [Revised: 05/25/2022] [Accepted: 05/26/2022] [Indexed: 11/26/2022] Open
Abstract
Na+-K+-ATPase, a P-type ATP-powered ion transporter on cell membrane, plays a vital role in cellular excitability. Cellular hyperexcitability, accompanied by hypersynchronous firing, is an important basis for seizures/epilepsy. An increasing number of studies point to a significant contribution of Na+-K+-ATPase to epilepsy, although discordant results exist. In this review, we comprehensively summarize the structure and physiological function of Na+-K+-ATPase in the central nervous system and critically evaluate the role of Na+-K+-ATPase in the epileptic brain. Importantly, we further provide perspectives on some possible research directions and discuss its potential as a therapeutic target for the treatment of epilepsy.
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Affiliation(s)
- Jinyi Sun
- Institute of Pharmacology & Toxicology, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, China
| | - Yang Zheng
- Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, School of Pharmaceutical Sciences, Zhejiang Chinese Medical University, Hangzhou, China
| | - Zhong Chen
- Institute of Pharmacology & Toxicology, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, China.,Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, School of Pharmaceutical Sciences, Zhejiang Chinese Medical University, Hangzhou, China.,Epilepsy Center, Department of Neurology, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China
| | - Yi Wang
- Institute of Pharmacology & Toxicology, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, China.,Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, School of Pharmaceutical Sciences, Zhejiang Chinese Medical University, Hangzhou, China.,Epilepsy Center, Department of Neurology, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China
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14
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Saba J, Couselo FL, Bruno J, Carniglia L, Durand D, Lasaga M, Caruso C. Neuroinflammation in Huntington's Disease: A Starring Role for Astrocyte and Microglia. Curr Neuropharmacol 2022; 20:1116-1143. [PMID: 34852742 PMCID: PMC9886821 DOI: 10.2174/1570159x19666211201094608] [Citation(s) in RCA: 27] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Revised: 10/06/2021] [Accepted: 11/26/2021] [Indexed: 11/22/2022] Open
Abstract
Huntington's disease (HD) is a neurodegenerative genetic disorder caused by a CAG repeat expansion in the huntingtin gene. HD causes motor, cognitive, and behavioral dysfunction. Since no existing treatment affects the course of this disease, new treatments are needed. Inflammation is frequently observed in HD patients before symptom onset. Neuroinflammation, characterized by the presence of reactive microglia, astrocytes and inflammatory factors within the brain, is also detected early. However, in comparison to other neurodegenerative diseases, the role of neuroinflammation in HD is much less known. Work has been dedicated to altered microglial and astrocytic functions in the context of HD, but less attention has been given to glial participation in neuroinflammation. This review describes evidence of inflammation in HD patients and animal models. It also discusses recent knowledge on neuroinflammation in HD, highlighting astrocyte and microglia involvement in the disease and considering anti-inflammatory therapeutic approaches.
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Affiliation(s)
- Julieta Saba
- Instituto de Investigaciones Biomédicas (INBIOMED), UBA-CONICET, Paraguay 2155, Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Federico López Couselo
- Instituto de Investigaciones Biomédicas (INBIOMED), UBA-CONICET, Paraguay 2155, Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Julieta Bruno
- Instituto de Investigaciones Biomédicas (INBIOMED), UBA-CONICET, Paraguay 2155, Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Lila Carniglia
- Instituto de Investigaciones Biomédicas (INBIOMED), UBA-CONICET, Paraguay 2155, Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Daniela Durand
- Instituto de Investigaciones Biomédicas (INBIOMED), UBA-CONICET, Paraguay 2155, Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Mercedes Lasaga
- Instituto de Investigaciones Biomédicas (INBIOMED), UBA-CONICET, Paraguay 2155, Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Carla Caruso
- Instituto de Investigaciones Biomédicas (INBIOMED), UBA-CONICET, Paraguay 2155, Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires, Argentina,Address correspondence to this author at the Instituto de Investigaciones Biomédicas (INBIOMED), UBA-CONICET, Paraguay 2155 Piso 10, Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires, Argentina, Tel: +54 11 5285 3380; E-mail:
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15
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Aldabbagh Y, Islam A, Zhang W, Whiting P, Ali AB. Alzheimer’s Disease Enhanced Tonic Inhibition is Correlated With Upregulated Astrocyte GABA Transporter-3/4 in a Knock-In APP Mouse Model. Front Pharmacol 2022; 13:822499. [PMID: 35185574 PMCID: PMC8850407 DOI: 10.3389/fphar.2022.822499] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2021] [Accepted: 01/12/2022] [Indexed: 11/25/2022] Open
Abstract
Cognitive decline is a major symptom in Alzheimer’s disease (AD), which is strongly associated with synaptic excitatory-inhibitory imbalance. Here, we investigated whether astrocyte-specific GABA transporter 3/4 (GAT3/4) is altered in APP knock-in mouse model of AD and whether this is correlated with changes in principal cell excitability. Using the APPNL-F/NL-F knock-in mouse model of AD, aged-matched to wild-type mice, we performed in vitro electrophysiological whole-cell recordings combined with immunohistochemistry in the CA1 and dentate gyrus (DG) regions of the hippocampus. We observed a higher expression of GAD67, an enzyme that catalyses GABA production, and GAT3/4 in reactive astrocytes labelled with GFAP, which correlated with an enhanced tonic inhibition in the CA1 and DG of 12–16 month-old APPNL-F/NL-F mice compared to the age-matched wild-type animals. Comparative neuroanatomy experiments performed using post-mortem brain tissue from human AD patients, age-matched to healthy controls, mirrored the results obtained using mice tissue. Blocking GAT3/4 associated tonic inhibition recorded in CA1 and DG principal cells resulted in an increased membrane input resistance, enhanced firing frequency and synaptic excitation in both wild-type and APPNL-F/NL-F mice. These effects exacerbated synaptic hyperactivity reported previously in the APPNL-F/NL-F mice model. Our data suggest that an alteration in astrocyte GABA homeostasis is correlated with increased tonic inhibition in the hippocampus, which probably plays an important compensatory role in restoring AD-associated synaptic hyperactivity. Therefore, reducing tonic inhibition through GAT3/4 may not be a good therapeutic strategy for AD
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Affiliation(s)
| | - Anam Islam
- UCL School of Pharmacy, London, United Kingdom
| | | | - Paul Whiting
- Alzheimer’s Research UK Drug Discovery Institute, Queen Square Institute of Neurology, London, United Kingdom
| | - Afia B. Ali
- UCL School of Pharmacy, London, United Kingdom
- *Correspondence: Afia B. Ali,
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16
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Serranilla M, Woodin MA. Striatal Chloride Dysregulation and Impaired GABAergic Signaling Due to Cation-Chloride Cotransporter Dysfunction in Huntington’s Disease. Front Cell Neurosci 2022; 15:817013. [PMID: 35095429 PMCID: PMC8795088 DOI: 10.3389/fncel.2021.817013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Accepted: 12/24/2021] [Indexed: 11/13/2022] Open
Abstract
Intracellular chloride (Cl–) levels in mature neurons must be tightly regulated for the maintenance of fast synaptic inhibition. In the mature central nervous system (CNS), synaptic inhibition is primarily mediated by gamma-amino butyric acid (GABA), which binds to Cl– permeable GABAA receptors (GABAARs). The intracellular Cl– concentration is primarily maintained by the antagonistic actions of two cation-chloride cotransporters (CCCs): Cl–-importing Na+-K+-Cl– co-transporter-1 (NKCC1) and Cl– -exporting K+-Cl– co-transporter-2 (KCC2). In mature neurons in the healthy brain, KCC2 expression is higher than NKCC1, leading to lower levels of intracellular Cl–, and Cl– influx upon GABAAR activation. However, in neurons of the immature brain or in neurological disorders such as epilepsy and traumatic brain injury, impaired KCC2 function and/or enhanced NKCC1 expression lead to intracellular Cl– accumulation and GABA-mediated excitation. In Huntington’s disease (HD), KCC2- and NKCC1-mediated Cl–-regulation are also altered, which leads to GABA-mediated excitation and contributes to the development of cognitive and motor impairments. This review summarizes the role of Cl– (dys)regulation in the healthy and HD brain, with a focus on the basal ganglia (BG) circuitry and CCCs as potential therapeutic targets in the treatment of HD.
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17
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Kovács Z, Skatchkov SN, Veh RW, Szabó Z, Németh K, Szabó PT, Kardos J, Héja L. Critical Role of Astrocytic Polyamine and GABA Metabolism in Epileptogenesis. Front Cell Neurosci 2022; 15:787319. [PMID: 35069115 PMCID: PMC8770812 DOI: 10.3389/fncel.2021.787319] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Accepted: 12/09/2021] [Indexed: 12/22/2022] Open
Abstract
Accumulating evidence indicate that astrocytes are essential players of the excitatory and inhibitory signaling during normal and epileptiform activity via uptake and release of gliotransmitters, ions, and other substances. Polyamines can be regarded as gliotransmitters since they are almost exclusively stored in astrocytes and can be released by various mechanisms. The polyamine putrescine (PUT) is utilized to synthesize GABA, which can also be released from astrocytes and provide tonic inhibition on neurons. The polyamine spermine (SPM), synthesized form PUT through spermidine (SPD), is known to unblock astrocytic Cx43 gap junction channels and therefore facilitate astrocytic synchronization. In addition, SPM released from astrocytes may also modulate neuronal NMDA, AMPA, and kainate receptors. As a consequence, astrocytic polyamines possess the capability to significantly modulate epileptiform activity. In this study, we investigated different steps in polyamine metabolism and coupled GABA release to assess their potential to control seizure generation and maintenance in two different epilepsy models: the low-[Mg2+] model of temporal lobe epilepsy in vitro and in the WAG/Rij rat model of absence epilepsy in vivo. We show that SPM is a gliotransmitter that is released from astrocytes and significantly contributes to network excitation. Importantly, we found that inhibition of SPD synthesis completely prevented seizure generation in WAG/Rij rats. We hypothesize that this antiepileptic effect is attributed to the subsequent enhancement of PUT to GABA conversion in astrocytes, leading to GABA release through GAT-2/3 transporters. This interpretation is supported by the observation that antiepileptic potential of the Food and Drug Administration (FDA)-approved drug levetiracetam can be diminished by specifically blocking astrocytic GAT-2/3 with SNAP-5114, suggesting that levetiracetam exerts its effect by increasing surface expression of GAT-2/3. Our findings conclusively suggest that the major pathway through which astrocytic polyamines contribute to epileptiform activity is the production of GABA. Modulation of astrocytic polyamine levels, therefore, may serve for a more effective antiepileptic drug development in the future.
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Affiliation(s)
- Zsolt Kovács
- Department of Biology, ELTE Eötvös Loránd University, Savaria University Centre, Szombathely, Hungary
| | - Serguei N. Skatchkov
- Department of Physiology, Universidad Central Del Caribe, Bayamon, PR, United States
- Department of Biochemistry, Universidad Central Del Caribe, Bayamon, PR, United States
| | - Rüdiger W. Veh
- Institut für Zell- und Neurobiologie, Centrum 2, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Zsolt Szabó
- Functional Pharmacology Research Group, Institute of Organic Chemistry, Research Centre for Natural Sciences, Eötvös Loránd Research Network, Budapest, Hungary
| | - Krisztina Németh
- MS Metabolomics Research Group, Centre for Structural Study, Research Centre for Natural Sciences, Eötvös Loránd Research Network, Budapest, Hungary
| | - Pál T. Szabó
- MS Metabolomics Research Group, Centre for Structural Study, Research Centre for Natural Sciences, Eötvös Loránd Research Network, Budapest, Hungary
| | - Julianna Kardos
- Functional Pharmacology Research Group, Institute of Organic Chemistry, Research Centre for Natural Sciences, Eötvös Loránd Research Network, Budapest, Hungary
| | - László Héja
- Functional Pharmacology Research Group, Institute of Organic Chemistry, Research Centre for Natural Sciences, Eötvös Loránd Research Network, Budapest, Hungary
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18
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Gorina YV, Salmina AB, Erofeev AI, Can Z, Bolshakova AV, Balaban PM, Bezprozvanny IB, Vlasova OL. Metabolic Plasticity of Astrocytes. J EVOL BIOCHEM PHYS+ 2021. [DOI: 10.1134/s0022093021060016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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19
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Sood A, Preeti K, Fernandes V, Khatri DK, Singh SB. Glia: A major player in glutamate-GABA dysregulation-mediated neurodegeneration. J Neurosci Res 2021; 99:3148-3189. [PMID: 34748682 DOI: 10.1002/jnr.24977] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Revised: 09/18/2021] [Accepted: 09/21/2021] [Indexed: 12/16/2022]
Abstract
The imbalance between glutamate and γ-aminobutyric acid (GABA) results in the loss of synaptic strength leading to neurodegeneration. The dogma on the field considered neurons as the main players in this excitation-inhibition (E/I) balance. However, current strategies focusing only on neurons have failed to completely understand this condition, bringing up the importance of glia as an alternative modulator for neuroinflammation as glia alter the activity of neurons and is a source of both neurotrophic and neurotoxic factors. This review's primary goal is to illustrate the role of glia over E/I balance in the central nervous system and its interaction with neurons. Rather than focusing only on the neuronal targets, we take a deeper look at glial receptors and proteins that could also be explored as drug targets, as they are early responders to neurotoxic insults. This review summarizes the neuron-glia interaction concerning GABA and glutamate, possible targets, and its involvement in the E/I imbalance in neurodegenerative diseases like Alzheimer's disease, Parkinson's disease, Huntington's disease, and multiple sclerosis.
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Affiliation(s)
- Anika Sood
- Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research (NIPER), Hyderabad, India
| | - Kumari Preeti
- Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research (NIPER), Hyderabad, India
| | - Valencia Fernandes
- Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research (NIPER), Hyderabad, India
| | - Dharmendra Kumar Khatri
- Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research (NIPER), Hyderabad, India
| | - Shashi Bala Singh
- Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research (NIPER), Hyderabad, India
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20
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Hong SI, Kang S, Baker M, Choi DS. Astrocyte-neuron interaction in the dorsal striatum-pallidal circuits and alcohol-seeking behaviors. Neuropharmacology 2021; 198:108759. [PMID: 34433087 DOI: 10.1016/j.neuropharm.2021.108759] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Revised: 07/21/2021] [Accepted: 08/11/2021] [Indexed: 12/31/2022]
Abstract
In the striatum, two main types of GABAergic medium spiny neurons (MSNs), denoted striatonigral (or direct-pathway MSNs, dMSNs) and striatopallidal neurons (indirect-pathway MSNs, iMSNs), form circuits with distinct pallidal nuclei, which sends "GO" or "NO-GO" signals through the thalamus. These striatopallidal circuits evaluate and execute reward-seeking and taking behaviors. Especially, the dorsal striatum can be further divided into the dorsomedial striatum (DMS, equivalent to caudate in primates and humans) and dorsolateral striatum (DLS, equivalent to putamen), which orchestrates goal-directed and habitual reward-seeking and taking behaviors, respectively. Using optogenetics, chemogenetics and in vivo calcium imaging technologies combined with electrophysiology and digitalized behavior phenotyping, recent studies have revealed cell-, circuit- and context-specific functions of these microcircuits in addictive behaviors. Also, region-specific astrocytes regulate the homeostatic activities of the dMSNs and iMSNs as well as the downstream circuits, which determine the net balance of cortico-striato-pallidal activities to the thalamic neurons. This review will summarize the recent progress of striatopallidal circuits focusing on astrocyte-neuron interaction and, reward- and alcohol-seeking behaviors. Our review will also discuss the translational and clinical implications of these microcircuit studies. This article is part of the special Issue on "Neurocircuitry Modulating Drug and Alcohol Abuse".
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Affiliation(s)
- Sa-Ik Hong
- Department of Molecular Pharmacology and Experimental Therapeutics, Rochester, MN, 55905, USA
| | - Seungwoo Kang
- Department of Molecular Pharmacology and Experimental Therapeutics, Rochester, MN, 55905, USA
| | - Matthew Baker
- Department of Molecular Pharmacology and Experimental Therapeutics, Rochester, MN, 55905, USA
| | - Doo-Sup Choi
- Department of Molecular Pharmacology and Experimental Therapeutics, Rochester, MN, 55905, USA; Department of Psychiatry and Psychology, Mayo Clinic College of Medicine and Science, Rochester, MN, 55905, USA.
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21
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Roberts BM, Lopes EF, Cragg SJ. Axonal Modulation of Striatal Dopamine Release by Local γ-Aminobutyric Acid (GABA) Signalling. Cells 2021; 10:709. [PMID: 33806845 PMCID: PMC8004767 DOI: 10.3390/cells10030709] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Revised: 03/16/2021] [Accepted: 03/19/2021] [Indexed: 12/21/2022] Open
Abstract
Striatal dopamine (DA) release is critical for motivated actions and reinforcement learning, and is locally influenced at the level of DA axons by other striatal neurotransmitters. Here, we review a wealth of historical and more recently refined evidence indicating that DA output is inhibited by striatal γ-aminobutyric acid (GABA) acting via GABAA and GABAB receptors. We review evidence supporting the localisation of GABAA and GABAB receptors to DA axons, as well as the identity of the striatal sources of GABA that likely contribute to GABAergic modulation of DA release. We discuss emerging data outlining the mechanisms through which GABAA and GABAB receptors inhibit the amplitude as well as modulate the short-term plasticity of DA release. Furthermore, we highlight recent data showing that DA release is governed by plasma membrane GABA uptake transporters on striatal astrocytes, which determine ambient striatal GABA tone and, by extension, the tonic inhibition of DA release. Finally, we discuss how the regulation of striatal GABA-DA interactions represents an axis for dysfunction in psychomotor disorders associated with dysregulated DA signalling, including Parkinson's disease, and could be a novel therapeutic target for drugs to modify striatal DA output.
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Affiliation(s)
| | | | - Stephanie J. Cragg
- Department of Physiology, Anatomy and Genetics, Centre for Integrative Neuroscience and Oxford Parkinson’s Disease Centre, University of Oxford, Oxford OX1 3PT, UK
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22
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Acioglu C, Li L, Elkabes S. Contribution of astrocytes to neuropathology of neurodegenerative diseases. Brain Res 2021; 1758:147291. [PMID: 33516810 DOI: 10.1016/j.brainres.2021.147291] [Citation(s) in RCA: 54] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Revised: 12/10/2020] [Accepted: 01/05/2021] [Indexed: 02/08/2023]
Abstract
Classically, the loss of vulnerable neuronal populations in neurodegenerative diseases was considered to be the consequence of cell autonomous degeneration of neurons. However, progress in the understanding of glial function, the availability of improved animal models recapitulating the features of the human diseases, and the development of new approaches to derive glia and neurons from induced pluripotent stem cells obtained from patients, provided novel information that altered this view. Current evidence strongly supports the notion that non-cell autonomous mechanisms contribute to the demise of neurons in neurodegenerative disorders, and glia causally participate in the pathogenesis and progression of these diseases. In addition to microglia, astrocytes have emerged as key players in neurodegenerative diseases and will be the focus of the present review. Under the influence of pathological stimuli present in the microenvironment of the diseased CNS, astrocytes undergo morphological, transcriptional, and functional changes and become reactive. Reactive astrocytes are heterogeneous and exhibit neurotoxic (A1) or neuroprotective (A2) phenotypes. In recent years, single-cell or single-nucleus transcriptome analyses unraveled new, disease-specific phenotypes beyond A1/A2. These investigations highlighted the complexity of the astrocytic responses to CNS pathology. The present review will discuss the contribution of astrocytes to neurodegenerative diseases with particular emphasis on Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis and frontotemporal dementia. Some of the commonalties and differences in astrocyte-mediated mechanisms that possibly drive the pathogenesis or progression of the diseases will be summarized. The emerging view is that astrocytes are potential new targets for therapeutic interventions. A comprehensive understanding of astrocyte heterogeneity and disease-specific phenotypic complexity could facilitate the design of novel strategies to treat neurodegenerative disorders.
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Affiliation(s)
- Cigdem Acioglu
- The Reynolds Family Spine Laboratory, Department of Neurological Surgery, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ 07103, United States.
| | - Lun Li
- The Reynolds Family Spine Laboratory, Department of Neurological Surgery, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ 07103, United States.
| | - Stella Elkabes
- The Reynolds Family Spine Laboratory, Department of Neurological Surgery, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ 07103, United States.
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23
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Rombaut B, Kessels S, Schepers M, Tiane A, Paes D, Solomina Y, Piccart E, Hove DVD, Brône B, Prickaerts J, Vanmierlo T. PDE inhibition in distinct cell types to reclaim the balance of synaptic plasticity. Theranostics 2021; 11:2080-2097. [PMID: 33500712 PMCID: PMC7797685 DOI: 10.7150/thno.50701] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Accepted: 11/17/2020] [Indexed: 02/06/2023] Open
Abstract
Synapses are the functional units of the brain. They form specific contact points that drive neuronal communication and are highly plastic in their strength, density, and shape. A carefully orchestrated balance between synaptogenesis and synaptic pruning, i.e., the elimination of weak or redundant synapses, ensures adequate synaptic density. An imbalance between these two processes lies at the basis of multiple neuropathologies. Recent evidence has highlighted the importance of glia-neuron interactions in the synaptic unit, emphasized by glial phagocytosis of synapses and local excretion of inflammatory mediators. These findings warrant a closer look into the molecular basis of cell-signaling pathways in the different brain cells that are related to synaptic plasticity. In neurons, intracellular second messengers, such as cyclic guanosine or adenosine monophosphate (cGMP and cAMP, respectively), are known mediators of synaptic homeostasis and plasticity. Increased levels of these second messengers in glial cells slow down inflammation and neurodegenerative processes. These multi-faceted effects provide the opportunity to counteract excessive synapse loss by targeting cGMP and cAMP pathways in multiple cell types. Phosphodiesterases (PDEs) are specialized degraders of these second messengers, rendering them attractive targets to combat the detrimental effects of neurological disorders. Cellular and subcellular compartmentalization of the specific isoforms of PDEs leads to divergent downstream effects for these enzymes in the various central nervous system resident cell types. This review provides a detailed overview on the role of PDEs and their inhibition in the context of glia-neuron interactions in different neuropathologies characterized by synapse loss. In doing so, it provides a framework to support future research towards finding combinational therapy for specific neuropathologies.
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24
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Cepeda C, Levine MS. Synaptic Dysfunction in Huntington's Disease: Lessons from Genetic Animal Models. Neuroscientist 2020; 28:20-40. [PMID: 33198566 DOI: 10.1177/1073858420972662] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The understanding of the functional and structural changes occurring in the cerebral cortex and basal ganglia in Huntington's disease (HD) has benefited considerably from the generation of genetic animal models. Most studies of synaptic alterations in HD models have focused on the striatum, but a more complete picture of synaptic dysfunction in the cortico-basal ganglia-cortical loop is emerging. Here, we provide a review and analysis of current developments in the study of synaptic alterations in these areas using HD rodent models. Recent evidence indicates that cortical maldevelopment plays a role in synaptic dysfunction along the corticostriatal pathway that may have its roots in the way mutant huntingtin interacts with synaptic proteins. Furthermore, a progressive disconnection in the corticostriatal pathway leads to abnormal function engaging extrasynaptic N-methyl-D-aspartate glutamate receptors that contribute to eventual cell degeneration. In addition, biphasic increases followed by decreases in glutamate and dopamine release in the striatum could explain contrasting symptomatology in early and late stages of the disease. Changes in striatal output regions also are beginning to be examined. Finally, we highlight some therapeutic avenues aimed at rescuing synaptic dysfunction.
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Affiliation(s)
- Carlos Cepeda
- IDDRC, Jane and Terry Semel Institute for Neuroscience & Human Behavior, David Geffen School of Medicine, University of California, Los Angeles, CA, USA
| | - Michael S Levine
- IDDRC, Jane and Terry Semel Institute for Neuroscience & Human Behavior, David Geffen School of Medicine, University of California, Los Angeles, CA, USA
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25
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Friedman A, Hueske E, Drammis SM, Toro Arana SE, Nelson ED, Carter CW, Delcasso S, Rodriguez RX, Lutwak H, DiMarco KS, Zhang Q, Rakocevic LI, Hu D, Xiong JK, Zhao J, Gibb LG, Yoshida T, Siciliano CA, Diefenbach TJ, Ramakrishnan C, Deisseroth K, Graybiel AM. Striosomes Mediate Value-Based Learning Vulnerable in Age and a Huntington's Disease Model. Cell 2020; 183:918-934.e49. [PMID: 33113354 DOI: 10.1016/j.cell.2020.09.060] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Revised: 07/10/2020] [Accepted: 09/24/2020] [Indexed: 12/21/2022]
Abstract
Learning valence-based responses to favorable and unfavorable options requires judgments of the relative value of the options, a process necessary for species survival. We found, using engineered mice, that circuit connectivity and function of the striosome compartment of the striatum are critical for this type of learning. Calcium imaging during valence-based learning exhibited a selective correlation between learning and striosomal but not matrix signals. This striosomal activity encoded discrimination learning and was correlated with task engagement, which, in turn, could be regulated by chemogenetic excitation and inhibition. Striosomal function during discrimination learning was disturbed with aging and severely so in a mouse model of Huntington's disease. Anatomical and functional connectivity of parvalbumin-positive, putative fast-spiking interneurons (FSIs) to striatal projection neurons was enhanced in striosomes compared with matrix in mice that learned. Computational modeling of these findings suggests that FSIs can modulate the striosomal signal-to-noise ratio, crucial for discrimination and learning.
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Affiliation(s)
- Alexander Friedman
- McGovern Institute for Brain Research and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Emily Hueske
- McGovern Institute for Brain Research and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Sabrina M Drammis
- McGovern Institute for Brain Research and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Sebastian E Toro Arana
- McGovern Institute for Brain Research and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Erik D Nelson
- McGovern Institute for Brain Research and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Cody W Carter
- McGovern Institute for Brain Research and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Sebastien Delcasso
- McGovern Institute for Brain Research and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Raimundo X Rodriguez
- McGovern Institute for Brain Research and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Hope Lutwak
- McGovern Institute for Brain Research and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Kaden S DiMarco
- McGovern Institute for Brain Research and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Qingyang Zhang
- McGovern Institute for Brain Research and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Lara I Rakocevic
- McGovern Institute for Brain Research and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Dan Hu
- McGovern Institute for Brain Research and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Joshua K Xiong
- McGovern Institute for Brain Research and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Jiajia Zhao
- McGovern Institute for Brain Research and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Leif G Gibb
- McGovern Institute for Brain Research and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Tomoko Yoshida
- McGovern Institute for Brain Research and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Cody A Siciliano
- McGovern Institute for Brain Research and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | | | - Charu Ramakrishnan
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA
| | - Karl Deisseroth
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA
| | - Ann M Graybiel
- McGovern Institute for Brain Research and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
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26
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Roberts BM, Doig NM, Brimblecombe KR, Lopes EF, Siddorn RE, Threlfell S, Connor-Robson N, Bengoa-Vergniory N, Pasternack N, Wade-Martins R, Magill PJ, Cragg SJ. GABA uptake transporters support dopamine release in dorsal striatum with maladaptive downregulation in a parkinsonism model. Nat Commun 2020; 11:4958. [PMID: 33009395 PMCID: PMC7532441 DOI: 10.1038/s41467-020-18247-5] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Accepted: 08/13/2020] [Indexed: 12/31/2022] Open
Abstract
Striatal dopamine (DA) is critical for action and learning. Recent data show that DA release is under tonic inhibition by striatal GABA. Ambient striatal GABA tone on striatal projection neurons can be determined by plasma membrane GABA uptake transporters (GATs) located on astrocytes and neurons. However, whether striatal GATs and astrocytes determine DA output are unknown. We reveal that DA release in mouse dorsolateral striatum, but not nucleus accumbens core, is governed by GAT-1 and GAT-3. These GATs are partly localized to astrocytes, and are enriched in dorsolateral striatum compared to accumbens core. In a mouse model of early parkinsonism, GATs are downregulated, tonic GABAergic inhibition of DA release augmented, and nigrostriatal GABA co-release attenuated. These data define previously unappreciated and important roles for GATs and astrocytes in supporting DA release in striatum, and reveal a maladaptive plasticity in early parkinsonism that impairs DA output in vulnerable striatal regions. GABA transporters expressed in the striatum may affect behaviour. Here the authors investigate the contribution of GABA transporters on astrocytes to the regulation of dopamine release in the striatum, and show decreased expression of GAT-1 and GAT-3 in a mouse model of Parkinsonism.
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Affiliation(s)
- Bradley M Roberts
- Centre for Integrative Neuroscience, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, OX1 3PT, UK. .,Oxford Parkinson's Disease Centre, University of Oxford, Oxford, OX1 3PT, UK.
| | - Natalie M Doig
- Medical Research Council Brain Network Dynamics Unit, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, OX1 3TH, UK
| | - Katherine R Brimblecombe
- Centre for Integrative Neuroscience, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, OX1 3PT, UK.,Oxford Parkinson's Disease Centre, University of Oxford, Oxford, OX1 3PT, UK
| | - Emanuel F Lopes
- Centre for Integrative Neuroscience, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, OX1 3PT, UK
| | - Ruth E Siddorn
- Centre for Integrative Neuroscience, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, OX1 3PT, UK
| | - Sarah Threlfell
- Centre for Integrative Neuroscience, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, OX1 3PT, UK.,Oxford Parkinson's Disease Centre, University of Oxford, Oxford, OX1 3PT, UK
| | - Natalie Connor-Robson
- Centre for Integrative Neuroscience, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, OX1 3PT, UK.,Oxford Parkinson's Disease Centre, University of Oxford, Oxford, OX1 3PT, UK
| | - Nora Bengoa-Vergniory
- Centre for Integrative Neuroscience, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, OX1 3PT, UK.,Oxford Parkinson's Disease Centre, University of Oxford, Oxford, OX1 3PT, UK
| | - Nicholas Pasternack
- Centre for Integrative Neuroscience, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, OX1 3PT, UK
| | - Richard Wade-Martins
- Centre for Integrative Neuroscience, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, OX1 3PT, UK.,Oxford Parkinson's Disease Centre, University of Oxford, Oxford, OX1 3PT, UK
| | - Peter J Magill
- Oxford Parkinson's Disease Centre, University of Oxford, Oxford, OX1 3PT, UK.,Medical Research Council Brain Network Dynamics Unit, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, OX1 3TH, UK
| | - Stephanie J Cragg
- Centre for Integrative Neuroscience, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, OX1 3PT, UK. .,Oxford Parkinson's Disease Centre, University of Oxford, Oxford, OX1 3PT, UK.
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27
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Kramer PF, Twedell EL, Shin JH, Zhang R, Khaliq ZM. Axonal mechanisms mediating γ-aminobutyric acid receptor type A (GABA-A) inhibition of striatal dopamine release. eLife 2020; 9:e55729. [PMID: 32870779 PMCID: PMC7462615 DOI: 10.7554/elife.55729] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Accepted: 08/15/2020] [Indexed: 01/03/2023] Open
Abstract
Axons of dopaminergic neurons innervate the striatum where they contribute to movement and reinforcement learning. Past work has shown that striatal GABA tonically inhibits dopamine release, but whether GABA-A receptors directly modulate transmission or act indirectly through circuit elements is unresolved. Here, we use whole-cell and perforated-patch recordings to test for GABA-A receptors on the main dopaminergic neuron axons and branching processes within the striatum of adult mice. Application of GABA depolarized axons, but also decreased the amplitude of axonal spikes, limited propagation and reduced striatal dopamine release. The mechanism of inhibition involved sodium channel inactivation and shunting. Lastly, we show the positive allosteric modulator diazepam enhanced GABA-A currents on dopaminergic axons and directly inhibited release, but also likely acts by reducing excitation from cholinergic interneurons. Thus, we reveal the mechanisms of GABA-A receptor modulation of dopamine release and provide new insights into the actions of benzodiazepines within the striatum.
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Affiliation(s)
- Paul F Kramer
- Cellular Neurophysiology Unit, National Institute of Neurological Disorders and Stroke, National Institutes of HealthBethesdaUnited States
| | - Emily L Twedell
- Cellular Neurophysiology Unit, National Institute of Neurological Disorders and Stroke, National Institutes of HealthBethesdaUnited States
| | - Jung Hoon Shin
- Laboratory on Neurobiology of Compulsive Behaviors, National Institute of Alcohol Abuse and Alcoholism, National Institutes of HealthBethesdaUnited States
| | - Renshu Zhang
- Cellular Neurophysiology Unit, National Institute of Neurological Disorders and Stroke, National Institutes of HealthBethesdaUnited States
| | - Zayd M Khaliq
- Cellular Neurophysiology Unit, National Institute of Neurological Disorders and Stroke, National Institutes of HealthBethesdaUnited States
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28
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An Astrocytic Influence on Impaired Tonic Inhibition in Hippocampal CA1 Pyramidal Neurons in a Mouse Model of Rett Syndrome. J Neurosci 2020; 40:6250-6261. [PMID: 32616668 DOI: 10.1523/jneurosci.3042-19.2020] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2019] [Revised: 05/13/2020] [Accepted: 06/10/2020] [Indexed: 01/28/2023] Open
Abstract
Rett syndrome (RTT) is a severe neurodevelopmental disease caused by mutations in the methyl-CpG binding protein 2 (MECP2) gene. Although altered interneuron development and function are clearly demonstrated in RTT mice, a particular mode of inhibition, tonic inhibition, has not been carefully examined. We report here that tonic inhibition is significantly reduced in pyramidal neurons in the CA1 region of the hippocampus in mice where Mecp2 is deleted either in all cells or specifically in astrocytes. Since no change is detected in the level of GABA receptors, such a reduction in tonic inhibition is likely a result of decreased ambient GABA level in the extracellular space. Consistent with this explanation, we observed increased expression of a GABA transporter, GABA transporter 3 (GAT3), in the hippocampus of the Mecp2 KO mice, as well as a corresponding increase of GAT3 current in hippocampal astrocytes. These phenotypes are relevant to RTT because pharmacological blockage of GAT3 can normalize tonic inhibition and intrinsic excitability in CA1 pyramidal neurons, and rescue the phenotype of increased network excitability in acute hippocampal slices from the Mecp2 KO mice. Finally, chronic administration of a GAT3 antagonist improved a composite symptom score and extended lifespan in the Mecp2 KO mice. Only male mice were used in this study. These results not only advance our understanding of RTT etiology by defining a new neuronal phenotype and revealing how it can be influenced by astrocytic alterations, but also reveal potential targets for intervention.SIGNIFICANCE STATEMENT Our study reports a novel phenotype of reduced tonic inhibition in hippocampal CA1 pyramidal neurons in the Rett syndrome mice, reveal a potential mechanism of increased GABA transporter expression/activity in the neighboring astrocytes, describe a disease-relevant consequence in hyperexcitability, and provide preliminary evidence that targeting this phenotype may slow down disease progression in Rett syndrome mice. These results help our understanding of the disease etiology and identify a new therapeutic target for treating Rett syndrome.
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29
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Łątka K, Jończyk J, Bajda M. γ-Aminobutyric acid transporters as relevant biological target: Their function, structure, inhibitors and role in the therapy of different diseases. Int J Biol Macromol 2020; 158:S0141-8130(20)32987-1. [PMID: 32360967 DOI: 10.1016/j.ijbiomac.2020.04.126] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2020] [Revised: 04/17/2020] [Accepted: 04/18/2020] [Indexed: 12/13/2022]
Abstract
γ-Aminobutyric acid (GABA) is a major inhibitory neurotransmitter in the nervous system. It plays a crucial role in many physiological processes. Upon release from the presynaptic element, it is removed from the synaptic cleft by reuptake due to the action of GABA transporters (GATs). GATs belong to a large SLC6 protein family whose characteristic feature is sodium-dependent relocation of neurotransmitters through the cell membrane. GABA transporters are characterized in many contexts, but their spatial structure is not fully known. They are divided into four types, which differ in occurrence and role. Herein, the special attention was paid to these transporting proteins. This comprehensive review presents the current knowledge about GABA transporters. Their distribution in the body, physiological functions and possible utilization in the therapy of different diseases were fully discussed. The important structural features were described based on published data, including sequence analysis, mutagenesis studies, and comparison with known SLC6 transporters for leucine (LeuT), dopamine (DAT) and serotonin (SERT). Moreover, the most important inhibitors of GABA transporters of various basic scaffolds, diverse selectivity and potency were presented.
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Affiliation(s)
- Kamil Łątka
- Jagiellonian University Medical College, Faculty of Pharmacy, Department of Physicochemical Drug Analysis, 30-688 Cracow, Medyczna 9, Poland
| | - Jakub Jończyk
- Jagiellonian University Medical College, Faculty of Pharmacy, Department of Physicochemical Drug Analysis, 30-688 Cracow, Medyczna 9, Poland
| | - Marek Bajda
- Jagiellonian University Medical College, Faculty of Pharmacy, Department of Physicochemical Drug Analysis, 30-688 Cracow, Medyczna 9, Poland.
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30
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Ponzi A, Barton SJ, Bunner KD, Rangel-Barajas C, Zhang ES, Miller BR, Rebec GV, Kozloski J. Striatal network modeling in Huntington's Disease. PLoS Comput Biol 2020; 16:e1007648. [PMID: 32302302 PMCID: PMC7197869 DOI: 10.1371/journal.pcbi.1007648] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Revised: 05/04/2020] [Accepted: 01/09/2020] [Indexed: 12/26/2022] Open
Abstract
Medium spiny neurons (MSNs) comprise over 90% of cells in the striatum. In vivo MSNs display coherent burst firing cell assembly activity patterns, even though isolated MSNs do not burst fire intrinsically. This activity is important for the learning and execution of action sequences and is characteristically dysregulated in Huntington's Disease (HD). However, how dysregulation is caused by the various neural pathologies affecting MSNs in HD is unknown. Previous modeling work using simple cell models has shown that cell assembly activity patterns can emerge as a result of MSN inhibitory network interactions. Here, by directly estimating MSN network model parameters from single unit spiking data, we show that a network composed of much more physiologically detailed MSNs provides an excellent quantitative fit to wild type (WT) mouse spiking data, but only when network parameters are appropriate for the striatum. We find the WT MSN network is situated in a regime close to a transition from stable to strongly fluctuating network dynamics. This regime facilitates the generation of low-dimensional slowly varying coherent activity patterns and confers high sensitivity to variations in cortical driving. By re-estimating the model on HD spiking data we discover network parameter modifications are consistent across three very different types of HD mutant mouse models (YAC128, Q175, R6/2). In striking agreement with the known pathophysiology we find feedforward excitatory drive is reduced in HD compared to WT mice, while recurrent inhibition also shows phenotype dependency. We show that these modifications shift the HD MSN network to a sub-optimal regime where higher dimensional incoherent rapidly fluctuating activity predominates. Our results provide insight into a diverse range of experimental findings in HD, including cognitive and motor symptoms, and may suggest new avenues for treatment.
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Affiliation(s)
- Adam Ponzi
- IBM Research, Computational Biology Center, Thomas J. Watson Research Laboratories, Yorktown Heights, New York, United States of America
- * E-mail:
| | - Scott J. Barton
- Program in Neuroscience, Department of Psychological and Brain Sciences, Indiana University, Bloomington, Indiana, United States of America
| | - Kendra D. Bunner
- Program in Neuroscience, Department of Psychological and Brain Sciences, Indiana University, Bloomington, Indiana, United States of America
| | - Claudia Rangel-Barajas
- Program in Neuroscience, Department of Psychological and Brain Sciences, Indiana University, Bloomington, Indiana, United States of America
| | - Emily S. Zhang
- Program in Neuroscience, Department of Psychological and Brain Sciences, Indiana University, Bloomington, Indiana, United States of America
| | - Benjamin R. Miller
- Program in Neuroscience, Department of Psychological and Brain Sciences, Indiana University, Bloomington, Indiana, United States of America
| | - George V. Rebec
- Program in Neuroscience, Department of Psychological and Brain Sciences, Indiana University, Bloomington, Indiana, United States of America
| | - James Kozloski
- IBM Research, Computational Biology Center, Thomas J. Watson Research Laboratories, Yorktown Heights, New York, United States of America
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31
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Chazalon M, Paredes-Rodriguez E, Morin S, Martinez A, Cristóvão-Ferreira S, Vaz S, Sebastiao A, Panatier A, Boué-Grabot E, Miguelez C, Baufreton J. GAT-3 Dysfunction Generates Tonic Inhibition in External Globus Pallidus Neurons in Parkinsonian Rodents. Cell Rep 2019; 23:1678-1690. [PMID: 29742425 DOI: 10.1016/j.celrep.2018.04.014] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Revised: 03/08/2018] [Accepted: 04/02/2018] [Indexed: 12/26/2022] Open
Abstract
The external globus pallidus (GP) is a key GABAergic hub in the basal ganglia (BG) circuitry, a neuronal network involved in motor control. In Parkinson's disease (PD), the rate and pattern of activity of GP neurons are profoundly altered and contribute to the motor symptoms of the disease. In rodent models of PD, the striato-pallidal pathway is hyperactive, and extracellular GABA concentrations are abnormally elevated in the GP, supporting the hypothesis of an alteration of neuronal and/or glial clearance of GABA. Here, we discovered the existence of persistent GABAergic tonic inhibition in GP neurons of dopamine-depleted (DD) rodent models. We showed that glial GAT-3 transporters are downregulated while neuronal GAT-1 function remains normal in DD rodents. Finally, we showed that blocking GAT-3 activity in vivo alters the motor coordination of control rodents, suggesting that GABAergic tonic inhibition in the GP contributes to the pathophysiology of PD.
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Affiliation(s)
- Marine Chazalon
- Université de Bordeaux, Institut des Maladies Neurodégénératives, 33000 Bordeaux, France; CNRS UMR 5293, Institut des Maladies Neurodégénératives, 33000 Bordeaux, France
| | | | - Stéphanie Morin
- Université de Bordeaux, Institut des Maladies Neurodégénératives, 33000 Bordeaux, France; CNRS UMR 5293, Institut des Maladies Neurodégénératives, 33000 Bordeaux, France
| | - Audrey Martinez
- Université de Bordeaux, Institut des Maladies Neurodégénératives, 33000 Bordeaux, France; CNRS UMR 5293, Institut des Maladies Neurodégénératives, 33000 Bordeaux, France
| | - Sofia Cristóvão-Ferreira
- Institute of Pharmacology and Neurosciences, Faculty of Medicine, and Unit of Neuroscience, Institute of Molecular Medicine, University of Lisbon, Lisbon, Portugal
| | - Sandra Vaz
- Institute of Pharmacology and Neurosciences, Faculty of Medicine, and Unit of Neuroscience, Institute of Molecular Medicine, University of Lisbon, Lisbon, Portugal
| | - Ana Sebastiao
- Institute of Pharmacology and Neurosciences, Faculty of Medicine, and Unit of Neuroscience, Institute of Molecular Medicine, University of Lisbon, Lisbon, Portugal
| | - Aude Panatier
- INSERM U1215, Neurocentre Magendie, 33000 Bordeaux, France; Université de Bordeaux, 33000 Bordeaux, France
| | - Eric Boué-Grabot
- Université de Bordeaux, Institut des Maladies Neurodégénératives, 33000 Bordeaux, France; CNRS UMR 5293, Institut des Maladies Neurodégénératives, 33000 Bordeaux, France
| | - Cristina Miguelez
- Department of Pharmacology, University of the Basque Country (UPV/EHU), 48940 Leioa, Spain
| | - Jérôme Baufreton
- Université de Bordeaux, Institut des Maladies Neurodégénératives, 33000 Bordeaux, France; CNRS UMR 5293, Institut des Maladies Neurodégénératives, 33000 Bordeaux, France.
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32
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NCX activity generates spontaneous Ca 2+ oscillations in the astrocytic leaflet microdomain. Cell Calcium 2019; 86:102137. [PMID: 31838438 DOI: 10.1016/j.ceca.2019.102137] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Revised: 12/01/2019] [Accepted: 12/01/2019] [Indexed: 12/13/2022]
Abstract
The synergy between synaptic Glu release and astrocytic Glu-Na+ symport is essential to the signalling function of the tripartite synapse. Here we used kinetic data of astrocytic Glu transporters (EAAT) and the Na+/Ca2+ exchanger (NCX) to simulate Glu release, Glu uptake and subsequent Na+ and Ca2+ dynamics in the astrocytic leaflet microdomain following single release event. Model simulations show that Glu-Na+ symport differently affect intracellular [Na+] in synapses with different extent of astrocytic coverage. Surprisingly, NCX activity alone has been shown to generate markedly stable, spontaneous Ca2+ oscillation in the astrocytic leaflet. These on-going oscillations appear when NCX operates either in the forward or reverse direction. We conjecture that intrinsic NCX activity may play a prominent role in the generation of astrocytic Ca2+ oscillations.
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Kardos J, Dobolyi Á, Szabó Z, Simon Á, Lourmet G, Palkovits M, Héja L. Molecular Plasticity of the Nucleus Accumbens Revisited-Astrocytic Waves Shall Rise. Mol Neurobiol 2019; 56:7950-7965. [PMID: 31134458 PMCID: PMC6834761 DOI: 10.1007/s12035-019-1641-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2018] [Accepted: 05/06/2019] [Indexed: 12/11/2022]
Abstract
Part of the ventral striatal division, the nucleus accumbens (NAc) drives the circuit activity of an entire macrosystem about reward like a "flagship," signaling and leading diverse conducts. Accordingly, NAc neurons feature complex inhibitory phenotypes that assemble to process circuit inputs and generate outputs by exploiting specific arrays of opposite and/or parallel neurotransmitters, neuromodulatory peptides. The resulting complex combinations enable versatile yet specific forms of accumbal circuit plasticity, including maladaptive behaviors. Although reward signaling and behavior are elaborately linked to neuronal circuit activities, it is plausible to propose whether these neuronal ensembles and synaptic islands can be directly controlled by astrocytes, a powerful modulator of neuronal activity. Pioneering studies showed that astrocytes in the NAc sense citrate cycle metabolites and/or ATP and may induce recurrent activation. We argue that the astrocytic calcium, GABA, and Glu signaling and altered sodium and chloride dynamics fundamentally shape metaplasticity by providing active regulatory roles in the synapse- and network-level flexibility of the NAc.
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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, Magyar tudósok körútja 2, Budapest, 1117, Hungary.
| | - Árpád Dobolyi
- Laboratory of Neuromorphology, Department of Anatomy, Histology and Embryology, Semmelweis University, Üllői út 26, Budapest, 1086, Hungary
- MTA-ELTE Laboratory of Molecular and Systems Neurobiology, Department of Physiology and Neurobiology, Eötvös Loránd University and the Hungarian Academy of Sciences, Pázmány Péter sétány 1C, Budapest, 1117, Hungary
| | - Zsolt Szabó
- Functional Pharmacology Research Group, Institute of Organic Chemistry, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Magyar tudósok körútja 2, Budapest, 1117, Hungary
| | - Ágnes Simon
- Functional Pharmacology Research Group, Institute of Organic Chemistry, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Magyar tudósok körútja 2, Budapest, 1117, Hungary
| | - Guillaume Lourmet
- Laboratory of Neuromorphology, Department of Anatomy, Histology and Embryology, Semmelweis University, Üllői út 26, Budapest, 1086, Hungary
| | - Miklós Palkovits
- Human Brain Tissue Bank, Semmelweis University, Tűzoltó utca 58, Budapest, H-1094, Hungary
| | - László Héja
- Functional Pharmacology Research Group, Institute of Organic Chemistry, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Magyar tudósok körútja 2, Budapest, 1117, Hungary
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34
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Escartin C, Guillemaud O, Carrillo-de Sauvage MA. Questions and (some) answers on reactive astrocytes. Glia 2019; 67:2221-2247. [PMID: 31429127 DOI: 10.1002/glia.23687] [Citation(s) in RCA: 168] [Impact Index Per Article: 33.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2019] [Revised: 06/12/2019] [Accepted: 06/28/2019] [Indexed: 02/06/2023]
Abstract
Astrocytes are key cellular partners for neurons in the central nervous system. Astrocytes react to virtually all types of pathological alterations in brain homeostasis by significant morphological and molecular changes. This response was classically viewed as stereotypical and is called astrogliosis or astrocyte reactivity. It was long considered as a nonspecific, secondary reaction to pathological conditions, offering no clues on disease-causing mechanisms and with little therapeutic value. However, many studies over the last 30 years have underlined the crucial and active roles played by astrocytes in physiology, ranging from metabolic support, synapse maturation, and pruning to fine regulation of synaptic transmission. This prompted researchers to explore how these new astrocyte functions were changed in disease, and they reported alterations in many of them (sometimes beneficial, mostly deleterious). More recently, cell-specific transcriptomics revealed that astrocytes undergo massive changes in gene expression when they become reactive. This observation further stressed that reactive astrocytes may be very different from normal, nonreactive astrocytes and could influence disease outcomes. To make the picture even more complex, both normal and reactive astrocytes were shown to be molecularly and functionally heterogeneous. Very little is known about the specific roles that each subtype of reactive astrocytes may play in different disease contexts. In this review, we have interrogated researchers in the field to identify and discuss points of consensus and controversies about reactive astrocytes, starting with their very name. We then present the emerging knowledge on these cells and future challenges in this field.
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Affiliation(s)
- Carole Escartin
- Commissariat à l'Energie Atomique et aux Energies Alternatives, Département de la Recherche Fondamentale, Institut de Biologie François Jacob, MIRCen, Fontenay-aux-Roses, France.,Centre National de la Recherche Scientifique, Univ. Paris Sud, Univ. Paris-Saclay, UMR 9199, Neurodegenerative Disease Laboratory, Fontenay-aux-Roses, France
| | - Océane Guillemaud
- Commissariat à l'Energie Atomique et aux Energies Alternatives, Département de la Recherche Fondamentale, Institut de Biologie François Jacob, MIRCen, Fontenay-aux-Roses, France.,Centre National de la Recherche Scientifique, Univ. Paris Sud, Univ. Paris-Saclay, UMR 9199, Neurodegenerative Disease Laboratory, Fontenay-aux-Roses, France
| | - Maria-Angeles Carrillo-de Sauvage
- Commissariat à l'Energie Atomique et aux Energies Alternatives, Département de la Recherche Fondamentale, Institut de Biologie François Jacob, MIRCen, Fontenay-aux-Roses, France.,Centre National de la Recherche Scientifique, Univ. Paris Sud, Univ. Paris-Saclay, UMR 9199, Neurodegenerative Disease Laboratory, Fontenay-aux-Roses, France
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35
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Khakh BS. Astrocyte-Neuron Interactions in the Striatum: Insights on Identity, Form, and Function. Trends Neurosci 2019; 42:617-630. [PMID: 31351745 PMCID: PMC6741427 DOI: 10.1016/j.tins.2019.06.003] [Citation(s) in RCA: 59] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Revised: 06/22/2019] [Accepted: 06/28/2019] [Indexed: 01/09/2023]
Abstract
The physiological functions of astrocytes within neural circuits remain incompletely understood. There has been progress in this regard from recent work on striatal astrocytes, where detailed studies are emerging. In this review, findings on striatal astrocyte identity, form, and function, are summarized with a focus on how astrocytes regulate striatal neurons, circuits, and behavior. Specific features of striatal astrocytes are highlighted to illustrate how they may be specialized to regulate medium spiny neurons (MSNs) by responding to, and altering, excitation and inhibition. Further experiments should reveal additional mechanisms for astrocyte-neuron interactions in the striatum and potentially reveal insights into the functions of astrocytes in neural circuits more generally.
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Affiliation(s)
- Baljit S Khakh
- Department of Physiology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095-1751, USA; Department of Neurobiology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095-1751, USA.
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36
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Oksanen M, Lehtonen S, Jaronen M, Goldsteins G, Hämäläinen RH, Koistinaho J. Astrocyte alterations in neurodegenerative pathologies and their modeling in human induced pluripotent stem cell platforms. Cell Mol Life Sci 2019; 76:2739-2760. [PMID: 31016348 PMCID: PMC6588647 DOI: 10.1007/s00018-019-03111-7] [Citation(s) in RCA: 81] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2018] [Revised: 04/06/2019] [Accepted: 04/16/2019] [Indexed: 12/12/2022]
Abstract
Astrocytes are the most abundant cell type in the brain. They were long considered only as passive support for neuronal cells. However, recent data have revealed many active roles for these cells both in maintenance of the normal physiological homeostasis in the brain as well as in neurodegeneration and disease. Moreover, human astrocytes have been found to be much more complex than their rodent counterparts, and to date, astrocytes are known to actively participate in a multitude of processes such as neurotransmitter uptake and recycling, gliotransmitter release, neuroenergetics, inflammation, modulation of synaptic activity, ionic balance, maintenance of the blood-brain barrier, and many other crucial functions of the brain. This review focuses on the role of astrocytes in human neurodegenerative disease and the potential of the novel stem cell-based platforms in modeling astrocytic functions in health and in disease.
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Affiliation(s)
- Minna Oksanen
- A.I.Virtanen Institute for Molecular Sciences, University of Eastern Finland, 70210, Kuopio, Finland
| | - Sarka Lehtonen
- A.I.Virtanen Institute for Molecular Sciences, University of Eastern Finland, 70210, Kuopio, Finland
- Neuroscience Center, Helsinki Institute of Life Science, University of Helsinki, PO. Box 63, 00290, Helsinki, Finland
| | - Merja Jaronen
- A.I.Virtanen Institute for Molecular Sciences, University of Eastern Finland, 70210, Kuopio, Finland
| | - Gundars Goldsteins
- A.I.Virtanen Institute for Molecular Sciences, University of Eastern Finland, 70210, Kuopio, Finland
| | - Riikka H Hämäläinen
- A.I.Virtanen Institute for Molecular Sciences, University of Eastern Finland, 70210, Kuopio, Finland
| | - Jari Koistinaho
- A.I.Virtanen Institute for Molecular Sciences, University of Eastern Finland, 70210, Kuopio, Finland.
- Neuroscience Center, Helsinki Institute of Life Science, University of Helsinki, PO. Box 63, 00290, Helsinki, Finland.
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37
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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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38
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Li K, Li J, Zheng J, Qin S. Reactive Astrocytes in Neurodegenerative Diseases. Aging Dis 2019; 10:664-675. [PMID: 31165009 PMCID: PMC6538217 DOI: 10.14336/ad.2018.0720] [Citation(s) in RCA: 234] [Impact Index Per Article: 46.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Accepted: 07/20/2018] [Indexed: 12/17/2022] Open
Abstract
Astrocytes, the largest and most numerous glial cells in the central nervous system (CNS), play a variety of important roles in regulating homeostasis, increasing synaptic plasticity and providing neuroprotection, thus helping to maintain normal brain function. At the same time, astrocytes can participate in the inflammatory response and play a key role in the progression of neurodegenerative diseases. Reactive astrocytes are strongly induced by numerous pathological conditions in the CNS. Astrocyte reactivity is initially characterized by hypertrophy of soma and processes, triggered by different molecules. Recent studies have demonstrated that neuroinflammation and ischemia can elicit two different types of reactive astrocytes, termed A1s and A2s. However, in the case of astrocyte reactivity in different neurodegenerative diseases, the recently published research issues remain a high level of conflict and controversy. So far, we still know very little about whether and how the function or reactivity of astrocytes changes in the progression of different neurodegenerative diseases. In this review, we aimed to briefly discuss recent studies highlighting the complex contribution of astrocytes in the process of various neurodegenerative diseases, which may provide us with new prospects for the development of an excellent therapeutic target for neurodegenerative diseases.
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Affiliation(s)
- Kunyu Li
- 1Department of Anatomy, Histology and Embryology, School of Basic Medical Sciences, Fudan University, Shanghai 200032, China
| | - Jiatong Li
- 1Department of Anatomy, Histology and Embryology, School of Basic Medical Sciences, Fudan University, Shanghai 200032, China
| | - Jialin Zheng
- 2Center for Translational Neurodegeneration and Regenerative Therapy, Shanghai Tenth People's Hospital affiliated to Tongji University School of Medicine, Shanghai, China
| | - Song Qin
- 1Department of Anatomy, Histology and Embryology, School of Basic Medical Sciences, Fudan University, Shanghai 200032, China
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39
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Mederos S, Perea G. GABAergic-astrocyte signaling: A refinement of inhibitory brain networks. Glia 2019; 67:1842-1851. [PMID: 31145508 PMCID: PMC6772151 DOI: 10.1002/glia.23644] [Citation(s) in RCA: 69] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Revised: 05/16/2019] [Accepted: 05/20/2019] [Indexed: 12/13/2022]
Abstract
Interneurons play a critical role in precise control of network operation. Indeed, higher brain capabilities such as working memory, cognitive flexibility, attention, or social interaction rely on the action of GABAergic interneurons. Evidence from excitatory neurons and synapses has revealed astrocytes as integral elements of synaptic transmission. However, GABAergic interneurons can also engage astrocyte signaling; therefore, it is tempting to speculate about different scenarios where, based on particular interneuron cell type, GABAergic‐astrocyte interplay would be involved in diverse outcomes of brain function. In this review, we will highlight current data supporting the existence of dynamic GABAergic‐astrocyte communication and its impact on the inhibitory‐regulated brain responses, bringing new perspectives on the ways astrocytes might contribute to efficient neuronal coding.
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Affiliation(s)
- Sara Mederos
- Department of Functional and Systems Neurobiology, Instituto Cajal, CSIC, Madrid, Spain
| | - Gertrudis Perea
- Department of Functional and Systems Neurobiology, Instituto Cajal, CSIC, Madrid, Spain
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40
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Héja L, Simon Á, Szabó Z, Kardos J. Feedback adaptation of synaptic excitability via Glu:Na + symport driven astrocytic GABA and Gln release. Neuropharmacology 2019; 161:107629. [PMID: 31103619 DOI: 10.1016/j.neuropharm.2019.05.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Revised: 03/30/2019] [Accepted: 05/07/2019] [Indexed: 02/08/2023]
Abstract
Glutamatergic transmission composed of the arriving of action potential at the axon terminal, fast vesicular Glu release, postsynaptic Glu receptor activation, astrocytic Glu clearance and Glu→Gln shuttle is an abundantly investigated phenomenon. Despite its essential role, however, much less is known about the consequences of the mechanistic connotations of Glu:Na+ symport. Due to the coupled Na+ transport, Glu uptake results in significantly elevated intracellular astrocytic [Na+] that markedly alters the driving force of other Na+-coupled astrocytic transporters. The resulting GABA and Gln release by reverse transport through the respective GAT-3 and SNAT3 transporters help to re-establish the physiological Na+ homeostasis without ATP dissipation and consequently leads to enhanced tonic inhibition and replenishment of axonal glutamate pool. Here, we place this emerging astrocytic adjustment of synaptic excitability into the centre of future perspectives. This article is part of the issue entitled 'Special Issue on Neurotransmitter Transporters'.
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Affiliation(s)
- László Héja
- Functional Pharmacology Research Group, Institute of Organic Chemistry, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Magyar tudósok körútja 2, 1117, Budapest, Hungary
| | - Ágnes Simon
- Functional Pharmacology Research Group, Institute of Organic Chemistry, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Magyar tudósok körútja 2, 1117, Budapest, Hungary
| | - Zsolt Szabó
- Functional Pharmacology Research Group, Institute of Organic Chemistry, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Magyar tudósok körútja 2, 1117, Budapest, Hungary
| | - Julianna Kardos
- Functional Pharmacology Research Group, Institute of Organic Chemistry, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Magyar tudósok körútja 2, 1117, Budapest, Hungary.
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41
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Hsu YT, Chang YG, Chern Y. Insights into GABA Aergic system alteration in Huntington's disease. Open Biol 2018; 8:rsob.180165. [PMID: 30518638 PMCID: PMC6303784 DOI: 10.1098/rsob.180165] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Accepted: 10/30/2018] [Indexed: 12/15/2022] Open
Abstract
Huntington's disease (HD) is an autosomal dominant progressive neurodegenerative disease that is characterized by a triad of motor, psychiatric and cognitive impairments. There is still no effective therapy to delay or halt the disease progress. The striatum and cortex are two particularly affected brain regions that exhibit dense reciprocal excitatory glutamate and inhibitory gamma-amino butyric acid (GABA) connections. Imbalance between excitatory and inhibitory signalling is known to greatly affect motor and cognitive processes. Emerging evidence supports the hypothesis that disrupted GABAergic circuits underlie HD pathogenesis. In the present review, we focused on the multiple defects recently found in the GABAergic inhibitory system, including altered GABA level and synthesis, abnormal subunit composition and distribution of GABAA receptors and aberrant GABAA receptor-mediated signalling. In particular, the important role of cation–chloride cotransporters (i.e. NKCC1 and KCC2) is discussed. Recent studies also suggest that neuroinflammation contributes significantly to the abnormal GABAergic inhibition in HD. Thus, GABAA receptors and cation–chloride cotransporters are potential therapeutic targets for HD. Given the limited availability of therapeutic treatments for HD, a better understanding of GABAergic dysfunction in HD could provide novel therapeutic opportunities.
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Affiliation(s)
- Yi-Ting Hsu
- PhD Program for Translational Medicine, China Medical University and Academia Sinica, Taiwan, Republic of China.,Department of Neurology, China Medical University Hospital, Taichung, Taiwan, Republic of China
| | - Ya-Gin Chang
- Institute of Neuroscience, National Yang-Ming University, Taipei, Taiwan, Republic of China.,Taiwan International Graduate Program in Interdisciplinary Neuroscience, National Yang-Ming University and Academia Sinica, Taipei, Taiwan, Republic of China
| | - Yijuang Chern
- PhD Program for Translational Medicine, China Medical University and Academia Sinica, Taiwan, Republic of China .,Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan, Republic of China
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42
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Yu X, Taylor AMW, Nagai J, Golshani P, Evans CJ, Coppola G, Khakh BS. Reducing Astrocyte Calcium Signaling In Vivo Alters Striatal Microcircuits and Causes Repetitive Behavior. Neuron 2018; 99:1170-1187.e9. [PMID: 30174118 PMCID: PMC6450394 DOI: 10.1016/j.neuron.2018.08.015] [Citation(s) in RCA: 217] [Impact Index Per Article: 36.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Revised: 05/23/2018] [Accepted: 08/10/2018] [Indexed: 01/01/2023]
Abstract
Astrocytes tile the central nervous system, but their functions in neural microcircuits in vivo and their roles in mammalian behavior remain incompletely defined. We used two-photon laser scanning microscopy, electrophysiology, MINIscopes, RNA-seq, and a genetic approach to explore the effects of reduced striatal astrocyte Ca2+ signaling in vivo. In wild-type mice, reducing striatal astrocyte Ca2+-dependent signaling increased repetitive self-grooming behaviors by altering medium spiny neuron (MSN) activity. The mechanism involved astrocyte-mediated neuromodulation facilitated by ambient GABA and was corrected by blocking astrocyte GABA transporter 3 (GAT-3). Furthermore, in a mouse model of Huntington's disease, dysregulation of GABA and astrocyte Ca2+ signaling accompanied excessive self-grooming, which was relieved by blocking GAT-3. Assessments with RNA-seq revealed astrocyte genes and pathways regulated by Ca2+ signaling in a cell-autonomous and non-cell-autonomous manner, including Rab11a, a regulator of GAT-3 functional expression. Thus, striatal astrocytes contribute to neuromodulation controlling mouse obsessive-compulsive-like behavior.
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Affiliation(s)
- Xinzhu Yu
- Department of Physiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095-1751, USA
| | - Anna M W Taylor
- Hatos Center for Neuropharmacology, Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095-1751, USA
| | - Jun Nagai
- Department of Physiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095-1751, USA
| | - Peyman Golshani
- Department of Neurology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095-1751, USA; Department of Psychiatry and Biobehavioral Sciences, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095-1751, USA; Intellectual and Developmental Disabilities Research Center, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095-1751, USA; West Los Angeles VA Medical Center, Los Angeles, CA 90073, USA
| | - Christopher J Evans
- Hatos Center for Neuropharmacology, Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095-1751, USA
| | - Giovanni Coppola
- Department of Neurology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095-1751, USA; Department of Psychiatry and Biobehavioral Sciences, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095-1751, USA; Intellectual and Developmental Disabilities Research Center, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095-1751, USA; Center for Neurobehavioral Genetics, Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095-1751, USA
| | - Baljit S Khakh
- Department of Physiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095-1751, USA; Department of Neurobiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095-1751, USA.
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43
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Al‐muhtasib N, Forcelli PA, Vicini S. Differential electrophysiological properties of D1 and D2 spiny projection neurons in the mouse nucleus accumbens core. Physiol Rep 2018; 6:e13784. [PMID: 29962016 PMCID: PMC6026590 DOI: 10.14814/phy2.13784] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2018] [Revised: 06/11/2018] [Accepted: 06/13/2018] [Indexed: 12/19/2022] Open
Abstract
The striatum consists of the dorsal (caudate/putamen) and the ventral (nucleus accumbens) regions. The nucleus accumbens is further divided into a core and shell. Both the dorsal and ventral striatum contain populations of spiny projection neurons, which make up 95% of the neurons within the striatum. SPNs are canonically categorized into those that express the D1-type dopamine receptor (D1 SPNs) and those that express the D2-type dopamine receptor (D2 SPNs). D1 and D2 SPNs differ with respect to both synaptic inputs and projection targets. In the dorsal striatum, it is well established that these populations of SPNs differ in terms of their electrophysiological and morphological properties. However, there remains a gap in our knowledge of the electrophysiological properties of SPNs in the nucleus accumbens core. To evaluate the differential properties of these SPNs, we performed whole-cell recordings from D1 and D2 SPNs in BAC transgenic mice in which D1 SPNs fluoresce red and D2 SPNs fluoresce green. The two SPN subtypes did not differ in terms of their time constant, capacitance, resting membrane potential, or tonic current. However, D2 SPNs displayed heightened inhibitory postsynaptic current (IPSC) and miniature excitatory PSC frequency as compared with D1 SPNs. Furthermore, D2 SPNs displayed decreased rheobase, increased excitability as measured by firing rates to depolarizing current injections, increased inward rectification, increased input resistance, and decreased dendritic complexity compared to D1 SPNs. Our results demonstrate a dichotomy in the electrophysiological properties of D1 and D2 SPNs in the nucleus accumbens core, which contributes to our knowledge of ventral striatal circuitry.
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Affiliation(s)
- Nour Al‐muhtasib
- Department of Pharmacology & PhysiologyGeorgetown University Medical CenterWashingtonDistrict of Columbia
| | - Patrick A. Forcelli
- Department of Pharmacology & PhysiologyGeorgetown University Medical CenterWashingtonDistrict of Columbia
- Interdisciplinary Program in NeuroscienceGeorgetown University Medical CenterWashingtonDistrict of Columbia
| | - Stefano Vicini
- Department of Pharmacology & PhysiologyGeorgetown University Medical CenterWashingtonDistrict of Columbia
- Interdisciplinary Program in NeuroscienceGeorgetown University Medical CenterWashingtonDistrict of Columbia
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44
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Blum D, Chern Y, Domenici MR, Buée L, Lin CY, Rea W, Ferré S, Popoli P. The Role of Adenosine Tone and Adenosine Receptors in Huntington's Disease. J Caffeine Adenosine Res 2018; 8:43-58. [PMID: 30023989 PMCID: PMC6049521 DOI: 10.1089/caff.2018.0006] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Huntington's disease (HD) is a hereditary neurodegenerative disorder caused by a mutation in the IT15 gene that encodes for the huntingtin protein. Mutated hungtingtin, although widely expressed in the brain, predominantly affects striato-pallidal neurons, particularly enriched with adenosine A2A receptors (A2AR), suggesting a possible involvement of adenosine and A2AR is the pathogenesis of HD. In fact, polymorphic variation in the ADORA2A gene influences the age at onset in HD, and A2AR dynamics is altered by mutated huntingtin. Basal levels of adenosine and adenosine receptors are involved in many processes critical for neuronal function and homeostasis, including modulation of synaptic activity and excitotoxicity, the control of neurotrophin levels and functions, and the regulation of protein degradation mechanisms. In the present review, we critically analyze the current literature involving the effect of altered adenosine tone and adenosine receptors in HD and discuss why therapeutics that modulate the adenosine system may represent a novel approach for the treatment of HD.
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Affiliation(s)
- David Blum
- University of Lille, Inserm, CHU Lille, UMR-S 1172 - JPArc, LabEx DISTALZ, Lille, France
| | - Yijuang Chern
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Maria Rosaria Domenici
- National Center for Drug Research and Evaluation, Istituto Superiore di Sanità, Rome, Italy
| | - Luc Buée
- University of Lille, Inserm, CHU Lille, UMR-S 1172 - JPArc, LabEx DISTALZ, Lille, France
| | - Chien-Yu Lin
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - William Rea
- Integrative Neurobiology Section, National Institute on Drug Abuse, National Institutes of Health, Baltimore, Maryland
| | - Sergi Ferré
- Integrative Neurobiology Section, National Institute on Drug Abuse, National Institutes of Health, Baltimore, Maryland
| | - Patrizia Popoli
- National Center for Drug Research and Evaluation, Istituto Superiore di Sanità, Rome, Italy
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Park A, Uddin O, Li Y, Masri R, Keller A. Pain After Spinal Cord Injury Is Associated With Abnormal Presynaptic Inhibition in the Posterior Nucleus of the Thalamus. THE JOURNAL OF PAIN 2018; 19:727.e1-727.e15. [PMID: 29481977 DOI: 10.1016/j.jpain.2018.02.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2017] [Revised: 01/29/2018] [Accepted: 02/12/2018] [Indexed: 01/21/2023]
Abstract
Pain after spinal cord injury (SCI-Pain) is one of the most debilitating sequelae of spinal cord injury, characterized as relentless, excruciating pain that is largely refractory to treatments. Although it is generally agreed that SCI-Pain results from maladaptive plasticity in the pain processing pathway that includes the spinothalamic tract and somatosensory thalamus, the specific mechanisms underlying the development and maintenance of such pain are yet unclear. However, accumulating evidence suggests that SCI-Pain may be causally related to abnormal thalamic disinhibition, leading to hyperactivity in the posterior thalamic nucleus (PO), a higher-order nucleus involved in somatosensory and pain processing. We previously described several presynaptic mechanisms by which activity in PO is regulated, including the regulation of GABAergic as well as glutamatergic release by presynaptic metabotropic gamma-aminobutyric acid (GABAB) receptors. Using acute slices from a mouse model of SCI-Pain, we tested whether such mechanisms are affected by SCI-Pain. We reveal 2 abnormal changes in presynaptic signaling in the SCI-Pain condition. The substantial tonic activation of presynaptic GABAB receptors on GABAergic projections to PO-characteristic of normal animals-was absent in mice with SCI-Pain. Also absent in mice with SCI-Pain was the normal presynaptic regulation of glutamatergic projections to the PO by GABAB receptors. The loss of these regulatory presynaptic mechanisms in SCI-Pain may be an element of maladaptive plasticity leading to PO hyperexcitability and behavioral pain, and may suggest targets for development of novel treatments. PERSPECTIVE This report presents synaptic mechanisms that may underlie the development and maintenance of SCI-Pain. Because of the difficulty in treating SCI-Pain, a better understanding of the underlying neurobiological mechanisms is critical, and may allow development of better treatment modalities.
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Affiliation(s)
- Anthony Park
- Program in Neuroscience and Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, Maryland
| | - Olivia Uddin
- Program in Neuroscience and Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, Maryland
| | - Ying Li
- Program in Neuroscience and Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, Maryland
| | - Radi Masri
- Program in Neuroscience and Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, Maryland; Department of Endodontics, Periodontics and Prosthodontics, University of Maryland Baltimore, School of Dentistry, Baltimore, Maryland
| | - Asaf Keller
- Program in Neuroscience and Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, Maryland.
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Garret M, Du Z, Chazalon M, Cho YH, Baufreton J. Alteration of GABAergic neurotransmission in Huntington's disease. CNS Neurosci Ther 2018; 24:292-300. [PMID: 29464851 DOI: 10.1111/cns.12826] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2017] [Revised: 01/23/2018] [Accepted: 01/26/2018] [Indexed: 12/16/2022] Open
Abstract
Hereditary Huntington's disease (HD) is characterized by cell dysfunction and death in the brain, leading to progressive cognitive, psychiatric, and motor impairments. Despite molecular and cellular descriptions of the effects of the HD mutation, no effective pharmacological treatment is yet available. In addition to well-established alterations of glutamatergic and dopaminergic neurotransmitter systems, it is becoming clear that the GABAergic systems are also impaired in HD. GABA is the major inhibitory neurotransmitter in the brain, and GABAergic neurotransmission has been postulated to be modified in many neurological and psychiatric diseases. In addition, GABAergic neurotransmission is the target of many drugs that are in wide clinical use. Here, we summarize data demonstrating the occurrence of alterations of GABAergic markers in the brain of HD carriers as well as in rodent models of the disease. In particular, we pinpoint HD-related changes in the expression of GABAA receptors (GABAA Rs). On the basis that a novel GABA pharmacology of GABAA Rs established with more selective drugs is emerging, we argue that clinical treatments acting specifically on GABAergic neurotransmission may be an appropriate strategy for improving symptoms linked to the HD mutation.
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Affiliation(s)
- Maurice Garret
- Université de Bordeaux, INCIA, UMR 5287, Bordeaux, France.,CNRS, INCIA, UMR 5287, Bordeaux, France
| | - Zhuowei Du
- Université de Bordeaux, INCIA, UMR 5287, Bordeaux, France.,CNRS, INCIA, UMR 5287, Bordeaux, France
| | - Marine Chazalon
- Institut des Maladies Neurodégénératives, Université de Bordeaux, UMR 5293, Bordeaux, France.,Institut des Maladies Neurodégénératives, CNRS, UMR 5293, Bordeaux, France
| | - Yoon H Cho
- Université de Bordeaux, INCIA, UMR 5287, Bordeaux, France.,CNRS, INCIA, UMR 5287, Bordeaux, France
| | - Jérôme Baufreton
- Institut des Maladies Neurodégénératives, Université de Bordeaux, UMR 5293, Bordeaux, France.,Institut des Maladies Neurodégénératives, CNRS, UMR 5293, Bordeaux, France
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Astrocytes and presynaptic plasticity in the striatum: Evidence and unanswered questions. Brain Res Bull 2018; 136:17-25. [DOI: 10.1016/j.brainresbull.2017.01.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Revised: 12/30/2016] [Accepted: 01/02/2017] [Indexed: 02/03/2023]
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Ferrer I. Diversity of astroglial responses across human neurodegenerative disorders and brain aging. Brain Pathol 2017; 27:645-674. [PMID: 28804999 PMCID: PMC8029391 DOI: 10.1111/bpa.12538] [Citation(s) in RCA: 81] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2017] [Accepted: 05/24/2017] [Indexed: 12/11/2022] Open
Abstract
Astrogliopathy refers to alterations of astrocytes occurring in diseases of the nervous system, and it implies the involvement of astrocytes as key elements in the pathogenesis and pathology of diseases and injuries of the central nervous system. Reactive astrocytosis refers to the response of astrocytes to different insults to the nervous system, whereas astrocytopathy indicates hypertrophy, atrophy/degeneration and loss of function and pathological remodeling occurring as a primary cause of a disease or as a factor contributing to the development and progression of a particular disease. Reactive astrocytosis secondary to neuron loss and astrocytopathy due to intrinsic alterations of astrocytes occur in neurodegenerative diseases, overlap each other, and, together with astrocyte senescence, contribute to disease-specific astrogliopathy in aging and neurodegenerative diseases with abnormal protein aggregates in old age. In addition to the well-known increase in glial fibrillary acidic protein and other proteins in reactive astrocytes, astrocytopathy is evidenced by deposition of abnormal proteins such as β-amyloid, hyper-phosphorylated tau, abnormal α-synuclein, mutated huntingtin, phosphorylated TDP-43 and mutated SOD1, and PrPres , in Alzheimer's disease, tauopathies, Lewy body diseases, Huntington's disease, amyotrophic lateral sclerosis and Creutzfeldt-Jakob disease, respectively. Astrocytopathy in these diseases can also be manifested by impaired glutamate transport; abnormal metabolism and release of neurotransmitters; altered potassium, calcium and water channels resulting in abnormal ion and water homeostasis; abnormal glucose metabolism; abnormal lipid and, particularly, cholesterol metabolism; increased oxidative damage and altered oxidative stress responses; increased production of cytokines and mediators of the inflammatory response; altered expression of connexins with deterioration of cell-to-cell networks and transfer of gliotransmitters; and worsening function of the blood brain barrier, among others. Increased knowledge of these aspects will permit a better understanding of brain aging and neurodegenerative diseases in old age as complex disorders in which neurons are not the only players.
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Affiliation(s)
- Isidro Ferrer
- Department of Pathology and Experimental TherapeuticsUniversity of BarcelonaBarcelonaSpain
- Institute of NeuropathologyPathologic Anatomy Service, Bellvitge University Hospital, IDIBELL, Hospitalet de LlobregatBarcelonaSpain
- Institute of NeurosciencesUniversity of BarcelonaBarcelonaSpain
- Biomedical Network Research Center on Neurodegenerative Diseases (CIBERNED), Institute Carlos IIIMadridSpain
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Functional Indicators of Glutamate Transport in Single Striatal Astrocytes and the Influence of Kir4.1 in Normal and Huntington Mice. J Neurosci 2017; 36:4959-75. [PMID: 27147650 DOI: 10.1523/jneurosci.0316-16.2016] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Accepted: 03/01/2016] [Indexed: 12/17/2022] Open
Abstract
UNLABELLED This study evaluates single-cell indicators of glutamate transport in sulforhodamine 101-positive astrocytes of Q175 mice, a knock-in model of Huntington's disease (HD). Transport-related fluorescent ratio signals obtained with sodium-binding benzofuran isophtalate (SBFI) AM from unperturbed or voltage-clamped astrocytes and respective glutamate transporter currents (GTCs) were induced by photolytic or synaptic glutamate release and isolated pharmacologically. The HD-induced deficit ranged from -27% (GTC maximum at -100 mV in Ba(2+)) to -41% (sodium transients in astrocytes after loading SBFI-AM). Our specific aim was to clarify the mechanism(s) by which Kir4.1 channels can influence glutamate transport, as determined by either Na(+) imaging or transport-associated electrical signals. A decrease of Kir4.1 conductance was mimicked with Ba(2+) (200 μm), and an increase of Kir4.1 expression was obtained by intravenous administration of AAV9-gfaABC1D-Kir4.1-EGFP. The decrease of Kir4.1 conductance reduced the sodium transients but increased the amplitudes of somatic GTCs. Accordingly, after genetic upregulation of Kir4.1, somatic GTCs were found to be decreased. In individual cells, there was a negative correlation between Kir4.1 currents and GTCs. The relative effect of the Kir4.1 conductance was higher in the astrocyte periphery. These and other results suggest that the Kir4.1 conductance affects glutamate transporter activity in a dual manner: (1) by providing the driving force (voltage dependency of the transport itself) and (2) by limiting the lateral charge transfer (thereby reducing the interference with other electrogenic transporter functions). This leads to the testable prediction that restoring the high conductance state of passive astrocytes will not only normalize glutamate uptake but also restore other astrocytic transporter activities afflicted with HD. SIGNIFICANCE STATEMENT Insufficiency of astrocytic glutamate uptake is a major element in the pathophysiology of neurodegenerative diseases. Considering the heterogeneity of astrocytes and their differential susceptibility to therapeutic interventions, it becomes necessary to evaluate the determinants of transport activity in individual astroglial cells. We have examined intracellular Na(+) transients and glutamate transporter currents as the most telling indicators of glutamate clearance after synaptic or photolytic release of glutamate in striatal slices. The results show that, in Huntington's disease, glutamate uptake activity critically depends on Kir4.1. These channels enable the high conductance state of the astrocytic plasma membrane, which ensures the driving force for glutamate transport and dumps the transport-associated depolarization along the astrocyte processes. This has significant implications for developing therapeutic targets.
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Liu B, Teschemacher AG, Kasparov S. Astroglia as a cellular target for neuroprotection and treatment of neuro-psychiatric disorders. Glia 2017; 65:1205-1226. [PMID: 28300322 PMCID: PMC5669250 DOI: 10.1002/glia.23136] [Citation(s) in RCA: 77] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Revised: 02/15/2017] [Accepted: 02/17/2017] [Indexed: 12/12/2022]
Abstract
Astrocytes are key homeostatic cells of the central nervous system. They cooperate with neurons at several levels, including ion and water homeostasis, chemical signal transmission, blood flow regulation, immune and oxidative stress defense, supply of metabolites and neurogenesis. Astroglia is also important for viability and maturation of stem-cell derived neurons. Neurons critically depend on intrinsic protective and supportive properties of astrocytes. Conversely, all forms of pathogenic stimuli which disturb astrocytic functions compromise neuronal functionality and viability. Support of neuroprotective functions of astrocytes is thus an important strategy for enhancing neuronal survival and improving outcomes in disease states. In this review, we first briefly examine how astrocytic dysfunction contributes to major neurological disorders, which are traditionally associated with malfunctioning of processes residing in neurons. Possible molecular entities within astrocytes that could underpin the cause, initiation and/or progression of various disorders are outlined. In the second section, we explore opportunities enhancing neuroprotective function of astroglia. We consider targeting astrocyte-specific molecular pathways which are involved in neuroprotection or could be expected to have a therapeutic value. Examples of those are oxidative stress defense mechanisms, glutamate uptake, purinergic signaling, water and ion homeostasis, connexin gap junctions, neurotrophic factors and the Nrf2-ARE pathway. We propose that enhancing the neuroprotective capacity of astrocytes is a viable strategy for improving brain resilience and developing new therapeutic approaches.
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Affiliation(s)
- Beihui Liu
- School of Physiology, Pharmacology and NeuroscienceUniversity of Bristol, University WalkBS8 1TDUnited Kingdom
| | - Anja G. Teschemacher
- School of Physiology, Pharmacology and NeuroscienceUniversity of Bristol, University WalkBS8 1TDUnited Kingdom
| | - Sergey Kasparov
- School of Physiology, Pharmacology and NeuroscienceUniversity of Bristol, University WalkBS8 1TDUnited Kingdom
- Institute for Chemistry and BiologyBaltic Federal UniversityKaliningradRussian Federation
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