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Alfahel L, Gschwendtberger T, Kozareva V, Dumas L, Gibbs R, Kertser A, Baruch K, Zaccai S, Kahn J, Thau-Habermann N, Eggenschwiler R, Sterneckert J, Hermann A, Sundararaman N, Vaibhav V, Van Eyk JE, Rafuse VF, Fraenkel E, Cantz T, Petri S, Israelson A. Targeting low levels of MIF expression as a potential therapeutic strategy for ALS. Cell Rep Med 2024; 5:101546. [PMID: 38703766 PMCID: PMC11148722 DOI: 10.1016/j.xcrm.2024.101546] [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: 05/17/2023] [Revised: 11/03/2023] [Accepted: 04/10/2024] [Indexed: 05/06/2024]
Abstract
Mutations in SOD1 cause amyotrophic lateral sclerosis (ALS), a neurodegenerative disease characterized by motor neuron (MN) loss. We previously discovered that macrophage migration inhibitory factor (MIF), whose levels are extremely low in spinal MNs, inhibits mutant SOD1 misfolding and toxicity. In this study, we show that a single peripheral injection of adeno-associated virus (AAV) delivering MIF into adult SOD1G37R mice significantly improves their motor function, delays disease progression, and extends survival. Moreover, MIF treatment reduces neuroinflammation and misfolded SOD1 accumulation, rescues MNs, and corrects dysregulated pathways as observed by proteomics and transcriptomics. Furthermore, we reveal low MIF levels in human induced pluripotent stem cell-derived MNs from familial ALS patients with different genetic mutations, as well as in post mortem tissues of sporadic ALS patients. Our findings indicate that peripheral MIF administration may provide a potential therapeutic mechanism for modulating misfolded SOD1 in vivo and disease outcome in ALS patients.
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Affiliation(s)
- Leenor Alfahel
- Department of Physiology and Cell Biology, Faculty of Health Sciences, Ben-Gurion University of the Negev, P.O.B. 653, Beer Sheva 84105, Israel; The School of Brain Sciences and Cognition, Ben-Gurion University of the Negev, P.O.B. 653, Beer Sheva 84105, Israel
| | - Thomas Gschwendtberger
- Department of Neurology, Hannover Medical School, 30625 Hannover, Germany; Center for Systems Neuroscience, Hannover Medical School, 30625 Hannover, Germany
| | - Velina Kozareva
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Laura Dumas
- Department of Medical Neuroscience, Dalhousie University, Halifax, Nova Scotia B3H 1X5, Canada; Brain Repair Centre, Life Sciences Research Institute, Halifax, Nova Scotia B3H 4R2, Canada
| | - Rachel Gibbs
- Department of Medical Neuroscience, Dalhousie University, Halifax, Nova Scotia B3H 1X5, Canada; Brain Repair Centre, Life Sciences Research Institute, Halifax, Nova Scotia B3H 4R2, Canada
| | | | - Kuti Baruch
- ImmunoBrain Checkpoint Ltd., Ness Ziona 7404905, Israel
| | - Shir Zaccai
- Department of Physiology and Cell Biology, Faculty of Health Sciences, Ben-Gurion University of the Negev, P.O.B. 653, Beer Sheva 84105, Israel; The School of Brain Sciences and Cognition, Ben-Gurion University of the Negev, P.O.B. 653, Beer Sheva 84105, Israel
| | - Joy Kahn
- Department of Physiology and Cell Biology, Faculty of Health Sciences, Ben-Gurion University of the Negev, P.O.B. 653, Beer Sheva 84105, Israel; The School of Brain Sciences and Cognition, Ben-Gurion University of the Negev, P.O.B. 653, Beer Sheva 84105, Israel
| | | | - Reto Eggenschwiler
- Gastroenterology, Hepatology and Endocrinology Department, Hannover Medical School, 30625 Hannover, Germany; Translational Hepatology and Stem Cell Biology, REBIRTH - Research Center for Translational Regenerative Medicine and Department of Gastroenterology, Hepatology and Endocrinology, Hannover Medical School, 30625 Hannover, Germany
| | - Jared Sterneckert
- Center for Regenerative Therapies Dresden, Technical University Dresden, 01307 Dresden, Germany
| | - Andreas Hermann
- Translational Neurodegeneration Section, "Albrecht Kossel", Department of Neurology, University Medical Center Rostock, University of Rostock, 18147 Rostock, Germany; Deutsches Zentrum für Neurodegenerative Erkrankungen (DZNE) Rostock/Greifswald, 18147 Rostock, Germany; Center for Transdisciplinary Neurosciences Rostock (CTNR), University Medical Center Rostock, University of Rostock, 18147 Rostock, Germany
| | - Niveda Sundararaman
- Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA; Advanced Clinical Biosystems Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
| | - Vineet Vaibhav
- Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA; Advanced Clinical Biosystems Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
| | - Jennifer E Van Eyk
- Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA; Advanced Clinical Biosystems Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
| | - Victor F Rafuse
- Department of Medical Neuroscience, Dalhousie University, Halifax, Nova Scotia B3H 1X5, Canada; Brain Repair Centre, Life Sciences Research Institute, Halifax, Nova Scotia B3H 4R2, Canada
| | - Ernest Fraenkel
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Tobias Cantz
- Gastroenterology, Hepatology and Endocrinology Department, Hannover Medical School, 30625 Hannover, Germany; Translational Hepatology and Stem Cell Biology, REBIRTH - Research Center for Translational Regenerative Medicine and Department of Gastroenterology, Hepatology and Endocrinology, Hannover Medical School, 30625 Hannover, Germany; Max Planck Institute for Molecular Biomedicine, Cell and Developmental Biology, 48149 Münster, Germany
| | - Susanne Petri
- Department of Neurology, Hannover Medical School, 30625 Hannover, Germany; Center for Systems Neuroscience, Hannover Medical School, 30625 Hannover, Germany
| | - Adrian Israelson
- Department of Physiology and Cell Biology, Faculty of Health Sciences, Ben-Gurion University of the Negev, P.O.B. 653, Beer Sheva 84105, Israel; The School of Brain Sciences and Cognition, Ben-Gurion University of the Negev, P.O.B. 653, Beer Sheva 84105, Israel.
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2
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Ratano P, Cocozza G, Pinchera C, Busdraghi LM, Cantando I, Martinello K, Scioli M, Rosito M, Bezzi P, Fucile S, Wulff H, Limatola C, D’Alessandro G. Reduction of inflammation and mitochondrial degeneration in mutant SOD1 mice through inhibition of voltage-gated potassium channel Kv1.3. Front Mol Neurosci 2024; 16:1333745. [PMID: 38292023 PMCID: PMC10824952 DOI: 10.3389/fnmol.2023.1333745] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2023] [Accepted: 12/31/2023] [Indexed: 02/01/2024] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease with no effective therapy, causing progressive loss of motor neurons in the spinal cord, brainstem, and motor cortex. Regardless of its genetic or sporadic origin, there is currently no cure for ALS or therapy that can reverse or control its progression. In the present study, taking advantage of a human superoxide dismutase-1 mutant (hSOD1-G93A) mouse that recapitulates key pathological features of human ALS, we investigated the possible role of voltage-gated potassium channel Kv1.3 in disease progression. We found that chronic administration of the brain-penetrant Kv1.3 inhibitor, PAP-1 (40 mg/Kg), in early symptomatic mice (i) improves motor deficits and prolongs survival of diseased mice (ii) reduces astrocyte reactivity, microglial Kv1.3 expression, and serum pro-inflammatory soluble factors (iii) improves structural mitochondrial deficits in motor neuron mitochondria (iv) restores mitochondrial respiratory dysfunction. Taken together, these findings underscore the potential significance of Kv1.3 activity as a contributing factor to the metabolic disturbances observed in ALS. Consequently, targeting Kv1.3 presents a promising avenue for modulating disease progression, shedding new light on potential therapeutic strategies for ALS.
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Affiliation(s)
| | - Germana Cocozza
- Department of Physiology and Pharmacology, University of Rome Sapienza, Rome, Italy
| | | | | | - Iva Cantando
- Department of Fundamental Neurosciences, University of Lausanne, Lausanne, Switzerland
| | | | | | - Maria Rosito
- Department of Physiology and Pharmacology, University of Rome Sapienza, Rome, Italy
| | - Paola Bezzi
- Department of Physiology and Pharmacology, University of Rome Sapienza, Rome, Italy
- Department of Fundamental Neurosciences, University of Lausanne, Lausanne, Switzerland
| | - Sergio Fucile
- IRCCS Neuromed, Pozzilli, Italy
- Department of Physiology and Pharmacology, University of Rome Sapienza, Rome, Italy
| | - Heike Wulff
- Department of Pharmacology, University of California Davis, Health Sciences Drive, Davis, CA, United States
| | - Cristina Limatola
- IRCCS Neuromed, Pozzilli, Italy
- Department of Physiology and Pharmacology, Laboratory Affiliated to Istituto Pasteur, Sapienza University, Rome, Italy
| | - Giuseppina D’Alessandro
- IRCCS Neuromed, Pozzilli, Italy
- Department of Physiology and Pharmacology, University of Rome Sapienza, Rome, Italy
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3
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Gullotta GS, Costantino G, Sortino MA, Spampinato SF. Microglia and the Blood-Brain Barrier: An External Player in Acute and Chronic Neuroinflammatory Conditions. Int J Mol Sci 2023; 24:ijms24119144. [PMID: 37298096 DOI: 10.3390/ijms24119144] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Revised: 05/18/2023] [Accepted: 05/20/2023] [Indexed: 06/12/2023] Open
Abstract
Microglia are the resident immune cells of the central nervous system that guarantee immune surveillance and exert also a modulating role on neuronal synaptic development and function. Upon injury, microglia get activated and modify their morphology acquiring an ameboid phenotype and pro- or anti-inflammatory features. The active role of microglia in blood-brain barrier (BBB) function and their interaction with different cellular components of the BBB-endothelial cells, astrocytes and pericytes-are described. Here, we report the specific crosstalk of microglia with all the BBB cell types focusing in particular on the involvement of microglia in the modulation of BBB function in neuroinflammatory conditions that occur in conjunction with an acute event, such as a stroke, or in a slow neurodegenerative disease, such as Alzheimer's disease. The potential of microglia to exert a dual role, either protective or detrimental, depending on disease stages and environmental conditioning factors is also discussed.
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Affiliation(s)
- Giorgia Serena Gullotta
- Department of Biomedical and Biotechnological Sciences, University of Catania, 95123 Catania, Italy
| | - Giuseppe Costantino
- Department of Biomedical and Biotechnological Sciences, University of Catania, 95123 Catania, Italy
- Ph.D. Program in Neuroscience and Education, DISTUM, University of Foggia, 71121 Foggia, Italy
| | - Maria Angela Sortino
- Department of Biomedical and Biotechnological Sciences, University of Catania, 95123 Catania, Italy
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Huffels CFM, Middeldorp J, Hol EM. Aß Pathology and Neuron-Glia Interactions: A Synaptocentric View. Neurochem Res 2023; 48:1026-1046. [PMID: 35976488 PMCID: PMC10030451 DOI: 10.1007/s11064-022-03699-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 06/30/2022] [Accepted: 07/15/2022] [Indexed: 10/15/2022]
Abstract
Alzheimer's disease (AD) causes the majority of dementia cases worldwide. Early pathological hallmarks include the accumulation of amyloid-ß (Aß) and activation of both astrocytes and microglia. Neurons form the building blocks of the central nervous system, and astrocytes and microglia provide essential input for its healthy functioning. Their function integrates at the level of the synapse, which is therefore sometimes referred to as the "quad-partite synapse". Increasing evidence puts AD forward as a disease of the synapse, where pre- and postsynaptic processes, as well as astrocyte and microglia functioning progressively deteriorate. Here, we aim to review the current knowledge on how Aß accumulation functionally affects the individual components of the quad-partite synapse. We highlight a selection of processes that are essential to the healthy functioning of the neuronal synapse, including presynaptic neurotransmitter release and postsynaptic receptor functioning. We further discuss how Aß affects the astrocyte's capacity to recycle neurotransmitters, release gliotransmitters, and maintain ion homeostasis. We additionally review literature on how Aß changes the immunoprotective function of microglia during AD progression and conclude by summarizing our main findings and highlighting the challenges in current studies, as well as the need for further research.
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Affiliation(s)
- Christiaan F M Huffels
- Department of Translational Neuroscience, University Medical Center Utrecht Brain Center, Utrecht University, Utrecht, The Netherlands
| | - Jinte Middeldorp
- Department of Translational Neuroscience, University Medical Center Utrecht Brain Center, Utrecht University, Utrecht, The Netherlands
- Department of Neurobiology & Aging, Biomedical Primate Research Centre, Rijswijk, The Netherlands
| | - Elly M Hol
- Department of Translational Neuroscience, University Medical Center Utrecht Brain Center, Utrecht University, Utrecht, The Netherlands.
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5
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Huang W, Xia Q, Zheng F, Zhao X, Ge F, Xiao J, Liu Z, Shen Y, Ye K, Wang D, Li Y. Microglia-Mediated Neurovascular Unit Dysfunction in Alzheimer's Disease. J Alzheimers Dis 2023; 94:S335-S354. [PMID: 36683511 PMCID: PMC10473143 DOI: 10.3233/jad-221064] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/17/2022] [Indexed: 01/21/2023]
Abstract
The neurovascular unit (NVU) is involved in the pathological changes in Alzheimer's disease (AD). The NVU is a structural and functional complex that maintains microenvironmental homeostasis and metabolic balance in the central nervous system. As one of the most important components of the NVU, microglia not only induce blood-brain barrier breakdown by promoting neuroinflammation, the infiltration of peripheral white blood cells and oxidative stress but also mediate neurovascular uncoupling by inducing mitochondrial dysfunction in neurons, abnormal contraction of cerebral vessels, and pericyte loss in AD. In addition, microglia-mediated dysfunction of cellular components in the NVU, such as astrocytes and pericytes, can destroy the integrity of the NVU and lead to NVU impairment. Therefore, we review the mechanisms of microglia-mediated NVU dysfunction in AD. Furthermore, existing therapeutic advancements aimed at restoring the function of microglia and the NVU in AD are discussed. Finally, we predict the role of pericytes in microglia-mediated NVU dysfunction in AD is the hotspot in the future.
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Affiliation(s)
- Wenhao Huang
- Department of Biochemistry and Molecular Biology, Harbin Medical University, Harbin, Heilongjiang Province, China
| | - Qing Xia
- Department of Biochemistry and Molecular Biology, Harbin Medical University, Harbin, Heilongjiang Province, China
- Dongzhimen Hospital, Beijing University of Chinese Medicine, Beijing, China
| | - Feifei Zheng
- Department of Biochemistry and Molecular Biology, Harbin Medical University, Harbin, Heilongjiang Province, China
| | - Xue Zhao
- Department of Biochemistry and Molecular Biology, Harbin Medical University, Harbin, Heilongjiang Province, China
| | - Fangliang Ge
- Department of Biochemistry and Molecular Biology, Harbin Medical University, Harbin, Heilongjiang Province, China
| | - Jiaying Xiao
- Department of Biochemistry and Molecular Biology, Harbin Medical University, Harbin, Heilongjiang Province, China
| | - Zijie Liu
- Department of Biochemistry and Molecular Biology, Harbin Medical University, Harbin, Heilongjiang Province, China
| | - Yingying Shen
- Department of Biochemistry and Molecular Biology, Harbin Medical University, Harbin, Heilongjiang Province, China
| | - Ke Ye
- Department of Biochemistry and Molecular Biology, Harbin Medical University, Harbin, Heilongjiang Province, China
| | - Dayong Wang
- Department of Biochemistry and Molecular Biology, Harbin Medical University, Harbin, Heilongjiang Province, China
- Basic Medical Institute, Heilongjiang Medical Science Academy, Harbin, Heilongjiang Province, China
- Translational Medicine Center of Northern China, Harbin, Heilongjiang Province, China
- Key Laboratory of Heilongjiang Province for Genetically Modified Animals, Harbin Medical University, Harbin, Heilongjiang Province, China
| | - Yanze Li
- Department of Biochemistry and Molecular Biology, Harbin Medical University, Harbin, Heilongjiang Province, China
- Basic Medical Institute, Heilongjiang Medical Science Academy, Harbin, Heilongjiang Province, China
- Translational Medicine Center of Northern China, Harbin, Heilongjiang Province, China
- Key Laboratory of Heilongjiang Province for Genetically Modified Animals, Harbin Medical University, Harbin, Heilongjiang Province, China
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de Oliveira Figueiredo EC, Calì C, Petrelli F, Bezzi P. Emerging evidence for astrocyte dysfunction in schizophrenia. Glia 2022; 70:1585-1604. [PMID: 35634946 PMCID: PMC9544982 DOI: 10.1002/glia.24221] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Revised: 05/09/2022] [Accepted: 05/13/2022] [Indexed: 12/30/2022]
Abstract
Schizophrenia is a complex, chronic mental health disorder whose heterogeneous genetic and neurobiological background influences early brain development, and whose precise etiology is still poorly understood. Schizophrenia is not characterized by gross brain pathology, but involves subtle pathological changes in neuronal populations and glial cells. Among the latter, astrocytes critically contribute to the regulation of early neurodevelopmental processes, and any dysfunctions in their morphological and functional maturation may lead to aberrant neurodevelopmental processes involved in the pathogenesis of schizophrenia, such as mitochondrial biogenesis, synaptogenesis, and glutamatergic and dopaminergic transmission. Studies of the mechanisms regulating astrocyte maturation may therefore improve our understanding of the cellular and molecular mechanisms underlying the pathogenesis of schizophrenia.
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Affiliation(s)
| | - Corrado Calì
- Department of Neuroscience, University of Torino, Torino, Italy.,Neuroscience Institute Cavalieri Ottolenghi, Orbassano, Italy
| | - Francesco Petrelli
- Department of Biomedical Sciences, University of Lausanne, Lausanne, Switzerland
| | - Paola Bezzi
- Department of Fundamental Neurosciences, University of Lausanne, Lausanne, Switzerland.,Department of Pharmacology and Physiology, University of Rome Sapienza, Rome, Italy
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Rieder P, Gobbo D, Stopper G, Welle A, Damo E, Kirchhoff F, Scheller A. Astrocytes and Microglia Exhibit Cell-Specific Ca2+ Signaling Dynamics in the Murine Spinal Cord. Front Mol Neurosci 2022; 15:840948. [PMID: 35431801 PMCID: PMC9006623 DOI: 10.3389/fnmol.2022.840948] [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: 12/21/2021] [Accepted: 02/22/2022] [Indexed: 12/31/2022] Open
Abstract
The spinal cord is the main pathway connecting brain and peripheral nervous system. Its functionality relies on the orchestrated activity of both neurons and glial cells. To date, most advancement in understanding the spinal cord inner mechanisms has been made either by in vivo exposure of its dorsal surface through laminectomy or by acute ex vivo slice preparation, likely affecting spinal cord physiology in virtue of the necessary extensive manipulation of the spinal cord tissue. This is especially true of cells immediately responding to alterations of the surrounding environment, such as microglia and astrocytes, reacting within seconds or minutes and for up to several days after the original insult. Ca2+ signaling is considered one of the most immediate, versatile, and yet elusive cellular responses of glia. Here, we induced the cell-specific expression of the genetically encoded Ca2+ indicator GCaMP3 to evaluate spontaneous intracellular Ca2+ signaling in astrocytes and microglia. Ca2+ signals were then characterized in acute ex vivo (both gray and white matter) as well as in chronic in vivo (white matter) preparations using MSparkles, a MATLAB-based software for automatic detection and analysis of fluorescence events. As a result, we were able to segregate distinct astroglial and microglial Ca2+ signaling patterns along with method-specific Ca2+ signaling alterations, which must be taken into consideration in the reliable evaluation of any result obtained in physiological as well as pathological conditions. Our study revealed a high degree of Ca2+ signaling diversity in glial cells of the murine spinal cord, thus adding to the current knowledge of the astonishing glial heterogeneity and cell-specific Ca2+ dynamics in non-neuronal networks.
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Affiliation(s)
- Phillip Rieder
- Department of Molecular Physiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), University of Saarland, Homburg, Germany
| | - Davide Gobbo
- Department of Molecular Physiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), University of Saarland, Homburg, Germany
| | - Gebhard Stopper
- Department of Molecular Physiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), University of Saarland, Homburg, Germany
| | - Anna Welle
- Department of Genetics and Epigenetics, University of Saarland, Saarbrücken, Germany
| | - Elisa Damo
- Department of Molecular Physiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), University of Saarland, Homburg, Germany
- Institute of Pharmacology, Medical Faculty Heidelberg, Heidelberg University, Heidelberg, Germany
| | - Frank Kirchhoff
- Department of Molecular Physiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), University of Saarland, Homburg, Germany
| | - Anja Scheller
- Department of Molecular Physiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), University of Saarland, Homburg, Germany
- *Correspondence: Anja Scheller,
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Abstract
Our understanding of astrocytes and their role in neurological diseases has increased considerably over the past two decades as the diverse roles of these cells have become recognized. Our evolving understanding of these cells suggests that they are more than support cells for neurons and that they play important roles in CNS homeostasis under normal conditions, in neuroprotection and in disease exacerbation. These multiple functions make them excellent candidates for targeted therapies to treat neurological disorders. New technological advances, including in vivo imaging, optogenetics and chemogenetics, have allowed us to examine astrocytic functions in ways that have uncovered new insights into the dynamic roles of these cells. Furthermore, the use of induced pluripotent stem cell-derived astrocytes from patients with a host of neurological disorders can help to tease out the contributions of astrocytes to human disease. In this Review, we explore some of the technological advances developed over the past decade that have aided our understanding of astrocyte function. We also highlight neurological disorders in which astrocyte function or dysfunction is believed to have a role in disease pathogenesis or propagation and discuss how the technological advances have been and could be used to study each of these diseases.
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Gómez-Gonzalo M, Zehnder T, Requie LM, Bezzi P, Carmignoto G. Insights into the release mechanism of astrocytic glutamate evoking in neurons NMDA receptor-mediated slow depolarizing inward currents. Glia 2018; 66:2188-2199. [DOI: 10.1002/glia.23473] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Revised: 04/27/2018] [Accepted: 05/25/2018] [Indexed: 12/19/2022]
Affiliation(s)
- Marta Gómez-Gonzalo
- Neuroscience Institute, National Research Council (CNR) and Department of Biomedical Sciences; University of Padova; Padova Italy
| | - Tamara Zehnder
- Department of Fundamental Neurosciences; University of Lausanne; Lausanne Switzerland
| | - Linda Maria Requie
- Neuroscience Institute, National Research Council (CNR) and Department of Biomedical Sciences; University of Padova; Padova Italy
| | - Paola Bezzi
- Department of Fundamental Neurosciences; University of Lausanne; Lausanne Switzerland
| | - Giorgio Carmignoto
- Neuroscience Institute, National Research Council (CNR) and Department of Biomedical Sciences; University of Padova; Padova Italy
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Ren Q, Wang ZZ, Chu SF, Xia CY, Chen NH. Gap junction channels as potential targets for the treatment of major depressive disorder. Psychopharmacology (Berl) 2018; 235:1-12. [PMID: 29178009 DOI: 10.1007/s00213-017-4782-7] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Accepted: 11/05/2017] [Indexed: 01/08/2023]
Abstract
BACKGROUND Major depressive disorder (MDD) remains a major public health problem worldwide. The association between MDD and the dysfunction of gap junction channels (GJCs) in glial cells, especially astrocytes, is still controversial. OBJECTIVE This review provides an overview of the role of astrocyte GJCs in LMDD. RESULTS Exposure to chronic unpredictable stress caused a reduction in connexin expression in the rat prefrontal cortex, a result that is consistent with clinical findings reported in postmortem studies of brains from MDD patients. Chronic antidepressant treatment in these rats increased the expression of connexins. However, pharmacological GJC blockade in normal rodents decreased connexin expression and caused depressive-like behaviors. Furthermore, GJC dysfunction affects electrical conductance, metabolic coupling and secondary messengers, and inflammatory responses, which are consistent with current hypotheses on MDD. All these results provide a comprehensive overview of the neurobiology of MDD. CONCLUSION This review supports the hypothesis that the regulation of GJCs between astrocytes could be an underlying mechanism for the therapeutic effect of antidepressants.
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Affiliation(s)
- Qian Ren
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica & Neuroscience Center, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100050, China
| | - Zhen-Zhen Wang
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica & Neuroscience Center, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100050, China
| | - Shi-Feng Chu
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica & Neuroscience Center, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100050, China
| | - Cong-Yuan Xia
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica & Neuroscience Center, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100050, China
| | - Nai-Hong Chen
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica & Neuroscience Center, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100050, China. .,College of Pharmacy, Hunan University of Chinese Medicine, Changsha, Hunan, 410208, China.
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11
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Chun H, Lee CJ. Reactive astrocytes in Alzheimer's disease: A double-edged sword. Neurosci Res 2017; 126:44-52. [PMID: 29225140 DOI: 10.1016/j.neures.2017.11.012] [Citation(s) in RCA: 107] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2017] [Revised: 11/07/2017] [Accepted: 11/07/2017] [Indexed: 12/13/2022]
Abstract
Alzheimer's disease (AD) is a chronic and fatal disease, in which neuronal damage at its late stage cannot be easily reversed. Because AD progression is caused by multiple factors including diverse cellular processes, studies on AD pathogenesis at the molecular and cellular level are challenging. Based on the lessons from unsuccessful neuron-focused research for an AD cure, non-cell autonomous mechanisms including brain inflammation and reactive astrocytes have recently been in the spotlight as potential therapeutic targets for AD. Studies have shown that reactive astrocytes are not only the result of inflammatory defense reactions, but also an active catabolic decomposer that acts by taking up amyloid beta toxins. Here, we give an overview of the characteristics of reactive astrocytes as pathological features of AD. Reactive astrocytes exert biphasic effects, that is, beneficial or detrimental depending on multiple factors. Many efforts have been put forth for defining and characterizing molecular signatures for the beneficial and detrimental reactive astrocytes. In the foreseeable future, manipulating and targeting each established molecular signature should have profound therapeutic implications for the treatment of AD.
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Affiliation(s)
- Heejung Chun
- Center for Neuro-Medicine, Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea
| | - C Justin Lee
- Center for Neuroscience and Functional Connectomics, Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea; Bio-Med, University of Science and Technology (UST), Daejeon, 34132, Republic of Korea; Center for Glia-Neuron Interaction, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea.
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Miller AP, Shah AS, Aperi BV, Kurpad SN, Stemper BD, Glavaski-Joksimovic A. Acute death of astrocytes in blast-exposed rat organotypic hippocampal slice cultures. PLoS One 2017; 12:e0173167. [PMID: 28264063 PMCID: PMC5338800 DOI: 10.1371/journal.pone.0173167] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2016] [Accepted: 02/16/2017] [Indexed: 01/06/2023] Open
Abstract
Blast traumatic brain injury (bTBI) affects civilians, soldiers, and veterans worldwide and presents significant health concerns. The mechanisms of neurodegeneration following bTBI remain elusive and current therapies are largely ineffective. It is important to better characterize blast-evoked cellular changes and underlying mechanisms in order to develop more effective therapies. In the present study, our group utilized rat organotypic hippocampal slice cultures (OHCs) as an in vitro system to model bTBI. OHCs were exposed to either 138 ± 22 kPa (low) or 273 ± 23 kPa (high) overpressures using an open-ended helium-driven shock tube, or were assigned to sham control group. At 2 hours (h) following injury, we have characterized the astrocytic response to a blast overpressure. Immunostaining against the astrocytic marker glial fibrillary acidic protein (GFAP) revealed acute shearing and morphological changes in astrocytes, including clasmatodendrosis. Moreover, overlap of GFAP immunostaining and propidium iodide (PI) indicated astrocytic death. Quantification of the number of dead astrocytes per counting area in the hippocampal cornu Ammonis 1 region (CA1), demonstrated a significant increase in dead astrocytes in the low- and high-blast, compared to sham control OHCs. However only a small number of GFAP-expressing astrocytes were co-labeled with the apoptotic marker Annexin V, suggesting necrosis as the primary type of cell death in the acute phase following blast exposure. Moreover, western blot analyses revealed calpain mediated breakdown of GFAP. The dextran exclusion additionally indicated membrane disruption as a potential mechanism of acute astrocytic death. Furthermore, although blast exposure did not evoke significant changes in glutamate transporter 1 (GLT-1) expression, loss of GLT-1-expressing astrocytes suggests dysregulation of glutamate uptake following injury. Our data illustrate the profound effect of blast overpressure on astrocytes in OHCs at 2 h following injury and suggest increased calpain activity and membrane disruption as potential underlying mechanisms.
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Affiliation(s)
- Anna P. Miller
- Department of Neurosurgery, Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America
- Department of Cell Biology, Neurobiology & Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America
- Clement J. Zablocki Veterans Affairs Medical Center, Milwaukee, Wisconsin, United States of America
| | - Alok S. Shah
- Department of Neurosurgery, Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America
- Clement J. Zablocki Veterans Affairs Medical Center, Milwaukee, Wisconsin, United States of America
| | - Brandy V. Aperi
- Department of Neurosurgery, Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America
- Clement J. Zablocki Veterans Affairs Medical Center, Milwaukee, Wisconsin, United States of America
| | - Shekar N. Kurpad
- Department of Neurosurgery, Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America
- Department of Cell Biology, Neurobiology & Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America
- Clement J. Zablocki Veterans Affairs Medical Center, Milwaukee, Wisconsin, United States of America
| | - Brian D. Stemper
- Department of Neurosurgery, Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America
- Clement J. Zablocki Veterans Affairs Medical Center, Milwaukee, Wisconsin, United States of America
| | - Aleksandra Glavaski-Joksimovic
- Department of Neurosurgery, Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America
- Department of Cell Biology, Neurobiology & Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America
- Clement J. Zablocki Veterans Affairs Medical Center, Milwaukee, Wisconsin, United States of America
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Bazargani N, Attwell D. Astrocyte calcium signaling: the third wave. Nat Neurosci 2016; 19:182-9. [PMID: 26814587 DOI: 10.1038/nn.4201] [Citation(s) in RCA: 559] [Impact Index Per Article: 69.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2015] [Accepted: 11/10/2015] [Indexed: 02/06/2023]
Abstract
The discovery that transient elevations of calcium concentration occur in astrocytes, and release 'gliotransmitters' which act on neurons and vascular smooth muscle, led to the idea that astrocytes are powerful regulators of neuronal spiking, synaptic plasticity and brain blood flow. These findings were challenged by a second wave of reports that astrocyte calcium transients did not mediate functions attributed to gliotransmitters and were too slow to generate blood flow increases. Remarkably, the tide has now turned again: the most important calcium transients occur in fine astrocyte processes not resolved in earlier studies, and new mechanisms have been discovered by which astrocyte [Ca(2+)]i is raised and exerts its effects. Here we review how this third wave of discoveries has changed our understanding of astrocyte calcium signaling and its consequences for neuronal function.
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Affiliation(s)
- Narges Bazargani
- Department of Neuroscience, Physiology &Pharmacology, University College London, London, UK
| | - David Attwell
- Department of Neuroscience, Physiology &Pharmacology, University College London, London, UK
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Rabinovich-Nikitin I, Ezra A, Barbiro B, Rabinovich-Toidman P, Solomon B. Chronic administration of AMD3100 increases survival and alleviates pathology in SOD1(G93A) mice model of ALS. J Neuroinflammation 2016; 13:123. [PMID: 27230771 PMCID: PMC4882847 DOI: 10.1186/s12974-016-0587-6] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2016] [Accepted: 05/17/2016] [Indexed: 12/26/2022] Open
Abstract
BACKGROUND Amyotrophic lateral sclerosis (ALS) is a progressive fatal neurodegenerative disease, involving both upper and lower motor neurons. The disease is induced by multifactorial pathologies, and as such, it requires a multifaceted therapeutic approach. CXCR4, a chemokine receptor widely expressed in neurons and glial cells and its ligand, CXCL12, also known as stromal-cell-derived factor (SDF1), modulate both neuronal function and apoptosis by glutamate release signaling as well as hematopoietic stem and progenitor cells (HSPCs) migration into the blood and their homing towards injured sites. Inhibition approaches towards the CXCR4/CXCL12 signaling may result in preventing neuronal apoptosis and alter the HSPCs migration and homing. Such inhibition can be achieved by means of treatment with AMD3100, an antagonist of the chemokine receptor CXCR4. METHODS We chronically treated male and female transgenic mice model of ALS, SOD1(G93A) mice, with AMD3100. Mice body weight and motor function, evaluated by Rotarod test, were recorded once a week. The most effective treatment regimen was repeated for biochemical and histological analyses in female mice. RESULTS We found that chronic administration of AMD3100 to SOD1(G93A) mice led to significant extension in mice lifespan and improved motor function and weight loss. In addition, the treatment significantly improved microglial pathology and decreased proinflammatory cytokines in spinal cords of treated female mice. Furthermore, AMD3100 treatment decreased blood-spinal cord barrier (BSCB) permeability by increasing tight junction proteins levels and increased the motor neurons count in the lamina X area of the spinal cord, where adult stem cells are formed. CONCLUSIONS These data, relevant to the corresponding disease mechanism in human ALS, suggest that blocking CXCR4 by the small molecule, AMD3100, may provide a novel candidate for ALS therapy with an increased safety.
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Affiliation(s)
- Inna Rabinovich-Nikitin
- Department of Molecular Microbiology and Biotechnology, George S. Wise Faculty of Life Sciences, Tel Aviv University, 69978, Tel Aviv, Israel
| | - Assaf Ezra
- Department of Molecular Microbiology and Biotechnology, George S. Wise Faculty of Life Sciences, Tel Aviv University, 69978, Tel Aviv, Israel
| | - Beka Barbiro
- Department of Molecular Microbiology and Biotechnology, George S. Wise Faculty of Life Sciences, Tel Aviv University, 69978, Tel Aviv, Israel
| | - Polina Rabinovich-Toidman
- Department of Molecular Microbiology and Biotechnology, George S. Wise Faculty of Life Sciences, Tel Aviv University, 69978, Tel Aviv, Israel
| | - Beka Solomon
- Department of Molecular Microbiology and Biotechnology, George S. Wise Faculty of Life Sciences, Tel Aviv University, 69978, Tel Aviv, Israel.
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Ben Haim L, Carrillo-de Sauvage MA, Ceyzériat K, Escartin C. Elusive roles for reactive astrocytes in neurodegenerative diseases. Front Cell Neurosci 2015; 9:278. [PMID: 26283915 PMCID: PMC4522610 DOI: 10.3389/fncel.2015.00278] [Citation(s) in RCA: 292] [Impact Index Per Article: 32.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2015] [Accepted: 07/06/2015] [Indexed: 12/21/2022] Open
Abstract
Astrocytes play crucial roles in the brain and are involved in the neuroinflammatory response. They become reactive in response to virtually all pathological situations in the brain such as axotomy, ischemia, infection, and neurodegenerative diseases (ND). Astrocyte reactivity was originally characterized by morphological changes (hypertrophy, remodeling of processes) and the overexpression of the intermediate filament glial fibrillary acidic protein (GFAP). However, it is unclear how the normal supportive functions of astrocytes are altered by their reactive state. In ND, in which neuronal dysfunction and astrocyte reactivity take place over several years or decades, the issue is even more complex and highly debated, with several conflicting reports published recently. In this review, we discuss studies addressing the contribution of reactive astrocytes to ND. We describe the molecular triggers leading to astrocyte reactivity during ND, examine how some key astrocyte functions may be enhanced or altered during the disease process, and discuss how astrocyte reactivity may globally affect ND progression. Finally we will consider the anticipated developments in this important field. With this review, we aim to show that the detailed study of reactive astrocytes may open new perspectives for ND.
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Affiliation(s)
- Lucile Ben Haim
- Commissariat à l'Energie Atomique et aux Energies Alternatives, Département des Sciences du Vivant, Institut d'Imagerie Biomédicale, MIRCen Fontenay-aux-Roses, France ; Neurodegenerative Diseases Laboratory, Centre National de la Recherche Scientifique, Université Paris-Sud, UMR 9199 Fontenay-aux-Roses, France
| | - Maria-Angeles Carrillo-de Sauvage
- Commissariat à l'Energie Atomique et aux Energies Alternatives, Département des Sciences du Vivant, Institut d'Imagerie Biomédicale, MIRCen Fontenay-aux-Roses, France ; Neurodegenerative Diseases Laboratory, Centre National de la Recherche Scientifique, Université Paris-Sud, UMR 9199 Fontenay-aux-Roses, France
| | - Kelly Ceyzériat
- Commissariat à l'Energie Atomique et aux Energies Alternatives, Département des Sciences du Vivant, Institut d'Imagerie Biomédicale, MIRCen Fontenay-aux-Roses, France ; Neurodegenerative Diseases Laboratory, Centre National de la Recherche Scientifique, Université Paris-Sud, UMR 9199 Fontenay-aux-Roses, France
| | - Carole Escartin
- Commissariat à l'Energie Atomique et aux Energies Alternatives, Département des Sciences du Vivant, Institut d'Imagerie Biomédicale, MIRCen Fontenay-aux-Roses, France ; Neurodegenerative Diseases Laboratory, Centre National de la Recherche Scientifique, Université Paris-Sud, UMR 9199 Fontenay-aux-Roses, France
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Astrocyte physiopathology: At the crossroads of intercellular networking, inflammation and cell death. Prog Neurobiol 2015; 130:86-120. [PMID: 25930681 DOI: 10.1016/j.pneurobio.2015.04.003] [Citation(s) in RCA: 139] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2014] [Revised: 04/15/2015] [Accepted: 04/20/2015] [Indexed: 12/11/2022]
Abstract
Recent breakthroughs in neuroscience have led to the awareness that we should revise our traditional mode of thinking and studying the CNS, i.e. by isolating the privileged network of "intelligent" synaptic contacts. We may instead need to contemplate all the variegate communications occurring between the different neural cell types, and centrally involving the astrocytes. Basically, it appears that a single astrocyte should be considered as a core that receives and integrates information from thousands of synapses, other glial cells and the blood vessels. In turn, it generates complex outputs that control the neural circuitry and coordinate it with the local microcirculation. Astrocytes thus emerge as the possible fulcrum of the functional homeostasis of the healthy CNS. Yet, evidence indicates that the bridging properties of the astrocytes can change in parallel with, or as a result of, the morphological, biochemical and functional alterations these cells undergo upon injury or disease. As a consequence, they have the potential to transform from supportive friends and interactive partners for neurons into noxious foes. In this review, we summarize the currently available knowledge on the contribution of astrocytes to the functioning of the CNS and what goes wrong in various pathological conditions, with a particular focus on Amyotrophic Lateral Sclerosis, Alzheimer's Disease and ischemia. The observations described convincingly demonstrate that the development and progression of several neurological disorders involve the de-regulation of a finely tuned interplay between multiple cell populations. Thus, it seems that a better understanding of the mechanisms governing the integrated communication and detrimental responses of the astrocytes as well as their impact towards the homeostasis and performance of the CNS is fundamental to open novel therapeutic perspectives.
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17
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Abnormal intracellular calcium signaling and SNARE-dependent exocytosis contributes to SOD1G93A astrocyte-mediated toxicity in amyotrophic lateral sclerosis. J Neurosci 2014; 34:2331-48. [PMID: 24501372 DOI: 10.1523/jneurosci.2689-13.2014] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Motor neurons are progressively and predominantly degenerated in ALS, which is not only induced by multiple intrinsic pathways but also significantly influenced by the neighboring glial cells. In particular, astrocytes derived from the SOD1 mutant mouse model of ALS or from human familial or sporadic ALS patient brain tissue directly induce motor neuron death in culture; however, the mechanisms of pathological astroglial secretion remain unclear. Here we investigated abnormal calcium homeostasis and altered exocytosis in SOD1G93A astrocytes. We found that purinergic stimulation induces excess calcium release from the ER stores in SOD1G93A astrocytes, which results from the abnormal ER calcium accumulation and is independent of clearance mechanisms. Furthermore, pharmacological studies suggested that store-operated calcium entry (SOCE), a calcium refilling mechanism responsive to ER calcium depletion, is enhanced in SOD1G93A astrocytes. We found that oxidant-induced increased S-glutathionylation and calcium-independent puncta formation of the ER calcium sensor STIM1 underlies the abnormal SOCE response in SOD1G93A astrocytes. Enhanced SOCE contributes to ER calcium overload in SOD1G93A astrocytes and excess calcium release from the ER during ATP stimulation. In addition, ER calcium release induces elevated ATP release from SOD1G93A astrocytes, which can be inhibited by the overexpression of dominant-negative SNARE. Selective inhibition of exocytosis in SOD1G93A astrocytes significantly prevents astrocyte-mediated toxicity to motor neurons and delays disease onset in SOD1G93A mice. Our results characterize a novel mechanism responsible for calcium dysregulation in SOD1G93A astrocytes and provide the first in vivo evidence that astrocyte exocytosis contributes to the pathogenesis of ALS.
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18
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Network-wide dysregulation of calcium homeostasis in Alzheimer’s disease. Cell Tissue Res 2014; 357:427-38. [DOI: 10.1007/s00441-014-1798-8] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2013] [Accepted: 01/09/2014] [Indexed: 12/19/2022]
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19
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G-protein coupled receptor-evoked glutamate exocytosis from astrocytes: role of prostaglandins. Neural Plast 2014; 2014:254574. [PMID: 24551459 PMCID: PMC3914554 DOI: 10.1155/2014/254574] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2013] [Accepted: 12/16/2013] [Indexed: 11/17/2022] Open
Abstract
Astrocytes are highly secretory cells, participating in rapid brain communication by releasing glutamate. Recent evidences have suggested that this process is largely mediated by Ca(2+)-dependent regulated exocytosis of VGLUT-positive vesicles. Here by taking advantage of VGLUT1-pHluorin and TIRF illumination, we characterized mechanisms of glutamate exocytosis evoked by endogenous transmitters (glutamate and ATP), which are known to stimulate Ca(2+) elevations in astrocytes. At first we characterized the VGLUT1-pHluorin expressing vesicles and found that VGLUT1-positive vesicles were a specific population of small synaptic-like microvesicles containing glutamate but which do not express VGLUT2. Endogenous mediators evoked a burst of exocytosis through activation of G-protein coupled receptors. Subsequent glutamate exocytosis was reduced by about 80% upon pharmacological blockade of the prostaglandin-forming enzyme, cyclooxygenase. On the other hand, receptor stimulation was accompanied by extracellular release of prostaglandin E2 (PGE2). Interestingly, administration of exogenous PGE2 produced per se rapid, store-dependent burst exocytosis of glutamatergic vesicles in astrocytes. Finally, when PGE2-neutralizing antibody was added to cell medium, transmitter-evoked exocytosis was again significantly reduced (by about 50%). Overall these data indicate that cyclooxygenase products are responsible for a major component of glutamate exocytosis in astrocytes and that large part of such component is sustained by autocrine/paracrine action of PGE2.
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20
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Brambilla L, Martorana F, Rossi D. Astrocyte signaling and neurodegeneration: new insights into CNS disorders. Prion 2012; 7:28-36. [PMID: 23093800 DOI: 10.4161/pri.22512] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Growing evidence indicates that astrocytes cannot be just considered as passive supportive cells deputed to preserve neuronal activity and survival, but rather they are involved in a striking number of active functions that are critical to the performance of the central nervous system (CNS). As a consequence, it is becoming more and more evident that the peculiar properties of these cells can actively contribute to the extraordinary functional complexity of the brain and spinal cord. This new perception of the functioning of the CNS opens up a wide range of new possibilities to interpret various physiological and pathological events, and moves the focus beyond the neuronal compartment toward astrocyte-neuron interactions. With this in mind, here we provide a synopsis of the activities astrocytes perform in normal conditions, and we try to discuss what goes wrong with these cells in specific pathological conditions, such as Alzheimer Disease, prion diseases and amyotrophic lateral sclerosis.
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Affiliation(s)
- Liliana Brambilla
- Laboratory for Research on Neurodegenerative Disorders, IRCCS Fondazione Salvatore Maugeri, Pavia, Italy
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21
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Benedusi V, Martorana F, Brambilla L, Maggi A, Rossi D. The peroxisome proliferator-activated receptor γ (PPARγ) controls natural protective mechanisms against lipid peroxidation in amyotrophic lateral sclerosis. J Biol Chem 2012; 287:35899-911. [PMID: 22910911 PMCID: PMC3476258 DOI: 10.1074/jbc.m112.366419] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Recent evidence highlights the peroxisome proliferator-activated receptors (PPARs) as critical neuroprotective factors in several neurodegenerative diseases, including amyotrophic lateral sclerosis (ALS). To gain new mechanistic insights into the role of these receptors in the context of ALS, here we investigated how PPAR transcriptional activity varies in hSOD1G93A ALS transgenic mice. We demonstrate that PPARγ-driven transcription selectively increases in the spinal cord of symptomatic hSOD1G93A mice. This phenomenon correlates with the up-regulation of target genes, such as lipoprotein lipase and glutathione S-transferase α-2, which are implicated in scavenging lipid peroxidation by-products. Such events are associated with enhanced PPARγ immunoreactivity within motor neuronal nuclei. This observation, and the fact that PPARγ displays increased responsiveness in cultured hSOD1G93A motor neurons, points to a role for this receptor in neutralizing deleterious lipoperoxidation derivatives within the motor cells. Consistently, in both motor neuron-like cultures and animal models, we report that PPARγ is activated by lipid peroxidation end products, such as 4-hydroxynonenal, whose levels are elevated in the cerebrospinal fluid and spinal cord from ALS patients. We propose that the accumulation of critical concentrations of lipid peroxidation adducts during ALS progression leads to the activation of PPARγ in motor neurons. This in turn triggers self-protective mechanisms that involve the up-regulation of lipid detoxification enzymes, such as lipoprotein lipase and glutathione S-transferase α-2. Our findings indicate that anticipating natural protective reactions by pharmacologically modulating PPARγ transcriptional activity may attenuate neurodegeneration by limiting the damage induced by lipid peroxidation derivatives.
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Affiliation(s)
- Valeria Benedusi
- Center of Excellence on Neurodegenerative Diseases and Department of Pharmacological and Biomolecular Sciences, University of Milan, 20133 Milan, Italy
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22
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Santello M, Calì C, Bezzi P. Gliotransmission and the tripartite synapse. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2012; 970:307-31. [PMID: 22351062 DOI: 10.1007/978-3-7091-0932-8_14] [Citation(s) in RCA: 145] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
In the last years, the classical view of glial cells (in particular of astrocytes) as a simple supportive cell for neurons has been replaced by a new vision in which glial cells are active elements of the brain. Such a new vision is based on the existence of a bidirectional communication between astrocytes and neurons at synaptic level. Indeed, perisynaptic processes of astrocytes express active G-protein-coupled receptors that are able (1) to sense neurotransmitters released from the synapse during synaptic activity, (2) to increase cytosolic levels of calcium, and (3) to stimulate the release of gliotransmitters that in turn can interact with the synaptic elements. The mechanism(s) by which astrocytes can release gliotransmitter has been extensively studied during the last years. Many evidences have suggested that a fraction of astrocytes in situ release neuroactive substances both with calcium-dependent and calcium-independent mechanism(s); whether these mechanisms coexist and under what physiological or pathological conditions they occur, it remains unclear. However, the calcium-dependent exocytotic vesicular release has received considerable attention due to its potential to occur under physiological conditions via a finely regulated way. By releasing gliotransmitters in millisecond time scale with a specific vesicular apparatus, astrocytes can integrate and process synaptic information and control or modulate synaptic transmission and plasticity.
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Affiliation(s)
- Mirko Santello
- DBCM, Department of Physiology, University of Bern, Bühlplatz 5, 3012 Bern, Switzerland
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Glial connexin expression and function in the context of Alzheimer's disease. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2011; 1818:2048-57. [PMID: 22008509 DOI: 10.1016/j.bbamem.2011.10.001] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2011] [Revised: 09/20/2011] [Accepted: 10/03/2011] [Indexed: 01/26/2023]
Abstract
A hallmark of neurodegenerative diseases is the reactive gliosis characterized by a phenotypic change in astrocytes and microglia. This glial response is associated with modifications in the expression and function of connexins (Cxs), the proteins forming gap junction channels and hemichannels. Increased Cx expression is detected in most reactive astrocytes located at amyloid plaques, the histopathological lesions typically present in the brain of Alzheimer's patients and animal models of the disease. The activity of Cx channels analyzed in vivo as well as in vitro after treatment with the amyloid β peptide is also modified and, in particular, hemichannel activation may contribute to neuronal damage. In this review, we summarize and discuss recent data that suggest glial Cx channels participate in the neurodegenerative process of Alzheimer's disease. This article is part of a Special Issue entitled: The Communicating junctions, composition, structure and characteristics.
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Abstract
The seminal discovery that glial cells, particularly astrocytes, can release a number of gliotransmitters that serve as signalling molecules for the cross-talk with neighbouring cellular populations has recently changed our perception of brain functioning, as well as our view of the pathogenesis of several disorders of the CNS. Since glutamate was one of the first gliotransmitters to be identified and characterized, we tackle the mechanisms that underlie its release from astrocytes, including the Ca2+ signals underlying its efflux from astroglia, and we discuss the involvement of these events in a number of relevant physiological processes, from the modulatory control of neighbouring synapses to the regulation of blood supply to cerebral tissues. The relevance of these mechanisms strongly indicates that the contribution of glial cells and gliotransmission to the activities of the brain cannot be overlooked, and any study of CNS physiopathology needs to consider glial biology to have a comprehensive overview of brain function and dysfunction. Abnormalites in the signalling that controls the astrocytic release of glutamate are described in several experimental models of neurological disorders, for example, AIDS dementia complex, Alzheimer's disease and cerebral ischaemia. While the modalities of glutamate release from astrocytes remain poorly understood, and this represents a major impediment to the definition of novel therapeutic strategies targeting this process at the molecular level, some key mediators deputed to the control of the glial release of this excitatory amino acid have been identified. Among these, we can mention, for instance, proinflammatory cytokines, such as tumour necrosis factor-α, and prostaglandins. Agents that are able to block the major steps of tumour necrosis factor-α and prostaglandin production and/or signalling can be proposed as novel therapeutic targets for the treatment of these disorders.
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Affiliation(s)
- Daniela Rossi
- Laboratory for Research on Neurodegenerative Disorders, IRCCS Fondazione Salvatore Maugeri, Pavia, Italy.
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25
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Ben Menachem-Zidon O, Avital A, Ben-Menahem Y, Goshen I, Kreisel T, Shmueli EM, Segal M, Ben Hur T, Yirmiya R. Astrocytes support hippocampal-dependent memory and long-term potentiation via interleukin-1 signaling. Brain Behav Immun 2011; 25:1008-16. [PMID: 21093580 DOI: 10.1016/j.bbi.2010.11.007] [Citation(s) in RCA: 88] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/16/2010] [Revised: 11/10/2010] [Accepted: 11/11/2010] [Indexed: 02/04/2023] Open
Abstract
Recent studies indicate that astrocytes play an integral role in neural and synaptic functioning. To examine the implications of these findings for neurobehavioral plasticity we investigated the involvement of astrocytes in memory and long-term potentiation (LTP), using a mouse model of impaired learning and synaptic plasticity caused by genetic deletion of the interleukin-1 receptor type I (IL-1RI). Neural precursor cells (NPCs), derived from either wild type (WT) or IL-1 receptor knockout (IL-1rKO) neonatal mice, were labeled with bromodeoxyuridine (BrdU) and transplanted into the hippocampus of either IL-1rKO or WT adult host mice. Transplanted NPCs survived and differentiated into astrocytes (expressing GFAP and S100β), but not to neurons or oligodendrocytes. The NPCs-derived astrocytes from WT but not IL-1rKO mice displayed co-localization of GFAP with the IL-1RI. Four to twelve weeks post-transplantation, memory functioning was examined in the fear-conditioning and the water maze paradigms and LTP of perforant path-dentate gyrus synapses was assessed in anesthetized mice. As expected, IL-1rKO mice transplanted with IL-1rKO cells or sham operated displayed severe memory disturbances in both paradigms as well as a marked impairment in LTP. In contrast, IL-1rKO mice transplanted with WT NPCs displayed a complete rescue of the impaired memory functioning as well as partial restoration of LTP. These findings indicate that astrocytes play a critical role in memory functioning and LTP, and specifically implicate astrocytic IL-1 signaling in these processes. The results suggest novel conceptualization and therapeutic targets for neuropsychiatric disorders characterized by impaired astrocytic functioning concomitantly with disturbed memory and synaptic plasticity.
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Santello M, Bezzi P, Volterra A. TNFα controls glutamatergic gliotransmission in the hippocampal dentate gyrus. Neuron 2011; 69:988-1001. [PMID: 21382557 DOI: 10.1016/j.neuron.2011.02.003] [Citation(s) in RCA: 266] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/22/2010] [Indexed: 02/07/2023]
Abstract
VIDEO ABSTRACT Glutamatergic gliotransmission provides a stimulatory input to excitatory synapses in the hippocampal dentate gyrus. Here, we show that tumor necrosis factor-alpha (TNFα) critically controls this process. With constitutive TNFα present, activation of astrocyte P2Y1 receptors induces localized [Ca(2+)](i) elevations followed by glutamate release and presynaptic NMDA receptor-dependent synaptic potentiation. In preparations lacking TNFα, astrocytes respond with identical [Ca(2+)](i) elevations but fail to induce neuromodulation. We find that TNFα specifically controls the glutamate release step of gliotransmission. In cultured astrocytes lacking TNFα glutamate exocytosis is dramatically slowed down due to altered vesicle docking. Addition of low picomolar TNFα promptly reconstitutes both normal exocytosis in culture and gliotransmission in situ. Alternatively, gliotransmission can be re-established without adding TNFα, by limiting glutamate uptake, which compensates slower release. These findings demonstrate that gliotransmission and its synaptic effects are controlled not only by astrocyte [Ca(2+)](i) elevations but also by permissive/homeostatic factors like TNFα.
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Affiliation(s)
- Mirko Santello
- Department of Cell Biology and Morphology, University of Lausanne, Lausanne, Switzerland
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27
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Shah RS, Chang SY, Min HK, Cho ZH, Blaha CD, Lee KH. Deep brain stimulation: technology at the cutting edge. J Clin Neurol 2010; 6:167-82. [PMID: 21264197 PMCID: PMC3024521 DOI: 10.3988/jcn.2010.6.4.167] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2010] [Revised: 09/16/2010] [Accepted: 09/16/2010] [Indexed: 01/15/2023] Open
Abstract
Deep brain stimulation (DBS) surgery has been performed in over 75,000 people worldwide, and has been shown to be an effective treatment for Parkinson's disease, tremor, dystonia, epilepsy, depression, Tourette's syndrome, and obsessive compulsive disorder. We review current and emerging evidence for the role of DBS in the management of a range of neurological and psychiatric conditions, and discuss the technical and practical aspects of performing DBS surgery. In the future, evolution of DBS technology may depend on several key areas, including better scientific understanding of its underlying mechanism of action, advances in high-spatial resolution imaging and development of novel electrophysiological and neurotransmitter microsensor systems. Such developments could form the basis of an intelligent closed-loop DBS system with feedback-guided neuromodulation to optimize both electrode placement and therapeutic efficacy.
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Affiliation(s)
- Rahul S Shah
- Department of Neurological Surgery, Mayo Clinic, Rochester, MN, USA
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Sidoryk-Wegrzynowicz M, Wegrzynowicz M, Lee E, Bowman AB, Aschner M. Role of astrocytes in brain function and disease. Toxicol Pathol 2010; 39:115-23. [PMID: 21075920 DOI: 10.1177/0192623310385254] [Citation(s) in RCA: 155] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Astrocytes assume multiple roles in maintaining an optimally suited milieu for neuronal function. Select astrocytic functions include the maintenance of redox potential, the production of trophic factors, the regulation of neurotransmitter and ion concentrations, and the removal of toxins and debris from the cerebrospinal fluid (CSF). Impairments in these and other functions, as well as physiological reactions of astrocytes to injury, can trigger or exacerbate neuronal dysfunction. This review addresses select metabolic interactions between neurons and astrocytes and emphasizes the role of astrocytes in mediating and amplifying the progression of several neurodegenerative disorders, such as Parkinson's disease (PD), hepatic encephalopathy (HE), hyperammonemia (HA), Alzheimer's disease (AD), and ischemia.
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Beattie MS, Ferguson AR, Bresnahan JC. AMPA-receptor trafficking and injury-induced cell death. Eur J Neurosci 2010; 32:290-7. [PMID: 20646045 DOI: 10.1111/j.1460-9568.2010.07343.x] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
AMPA receptors (AMPARs) are critical for synaptic plasticity, and are subject to alterations based on subunit composition and receptor trafficking to and from the plasma membrane. One of the most potent regulators of AMPAR trafficking is the pro-inflammatory cytokine tumor necrosis factor (TNF)α, which is involved in physiological regulation of synaptic strength (Beattie et al., (2002) Science, 295, 2282-2285; Stellwagen and Malenka, (2006) Nature, 440, 1054-1059) and is also present at high concentrations after CNS injury. Here, we review evidence that TNF can rapidly alter the surface expression of AMPARs so that the proportion of Ca(++) -permeable receptors is increased and that this increase, in combination with increased levels of extracellular glutamate after injury, plays an important role in enhancing excitotoxic cell death after CNS injury. Thus, the pathophysiological hijacking of a critical regulator of synaptic plasticity and homeostasis by the secondary injury cascade may represent a new therapeutic target for neuroprotection.
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Affiliation(s)
- Michael S Beattie
- Brain and Spinal Injury Center, Department of Neurological Surgery, University of California, San Francisco, Bldg. 1, Rm 101, San Francisco, CA 94110, USA.
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Rossi D, Volterra A. Astrocytic dysfunction: Insights on the role in neurodegeneration. Brain Res Bull 2009; 80:224-32. [DOI: 10.1016/j.brainresbull.2009.07.012] [Citation(s) in RCA: 149] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2009] [Revised: 07/15/2009] [Accepted: 07/16/2009] [Indexed: 12/11/2022]
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Barenco MG, Valori CF, Roncoroni C, Loewer J, Montrasio F, Rossi D. Deletion of the amino-terminal domain of the prion protein does not impair prion protein-dependent neuronal differentiation and neuritogenesis. J Neurosci Res 2009; 87:806-19. [DOI: 10.1002/jnr.21894] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Murthy SRK, Teodorescu G, Nijholt IM, Dolga AM, Grissmer S, Spiess J, Blank T. Identification and characterization of a novel, shorter isoform of the small conductance Ca2+-activated K+channel SK2. J Neurochem 2008; 106:2312-21. [DOI: 10.1111/j.1471-4159.2008.05557.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Boetkjaer A, Boedker M, Cui JG, Zhao Y, Lukiw WJ. Synergism in the repression of COX-2- and TNFalpha-induction in platelet activating factor-stressed human neural cells. Neurosci Lett 2007; 426:59-63. [PMID: 17881124 PMCID: PMC2083574 DOI: 10.1016/j.neulet.2007.08.050] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2007] [Revised: 08/14/2007] [Accepted: 08/15/2007] [Indexed: 11/25/2022]
Abstract
Platelet activating factor (PAF; beta-acetyl-gamma-O-hexadecyl-l-alpha-phosphatidylcholine) triggers a rapid pro-inflammatory gene expression program in primary cultures of human neural (HN) cells. Two genes and gene products consistently induced after PAF treatment are the cytosoluble prostaglandin synthase cycloooxygenase-2 (COX-2) and the pro-apoptotic tumor necrosis factor alpha (TNFalpha). Both of these mediators are associated with the activation of inflammatory signaling, neural cell dysfunction, apoptosis and brain cell death, and both have been found to be up-regulated after brain injury in vivo. In this study we investigated the effects of the non-halogenated synthetic glucocorticoid budesonide epimer R (BUDeR), the novel PAF antagonist LAU-0901, and the electron spin trap and free radical scavenger phenyl butyl nitrone (PBN), upon early COX-2 and TNFalpha gene activation and prostaglandin E(2) (PGE(2)) release in PAF-stressed primary HN cells. The data indicate that these three biochemically unrelated classes of inflammatory repressors act synergistically in modulating PAF-induced up-regulation of COX-2, TNFalpha, and PGE(2) by quenching oxidative stress or inflammatory signaling, resulting in increased HN cell survival. These, or analogous classes of compounds, may be useful in the design of more effective combinatorial pharmacotherapeutic strategies in the treatment of complex neuro-inflammatory disorders.
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Affiliation(s)
- Anja Boetkjaer
- The Danish University of Pharmaceutical Sciences, Universitetsparken 2, DK 2100 Copenhagen, Denmark
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Malarkey EB, Parpura V. Mechanisms of glutamate release from astrocytes. Neurochem Int 2007; 52:142-54. [PMID: 17669556 PMCID: PMC2267911 DOI: 10.1016/j.neuint.2007.06.005] [Citation(s) in RCA: 255] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/07/2007] [Indexed: 11/22/2022]
Abstract
Astrocytes can release the excitatory transmitter glutamate which is capable of modulating activity in nearby neurons. This astrocytic glutamate release can occur through six known mechanisms: (i) reversal of uptake by glutamate transporters (ii) anion channel opening induced by cell swelling, (iii) Ca2+-dependent exocytosis, (iv) glutamate exchange via the cystine-glutamate antiporter, (v) release through ionotropic purinergic receptors and (vi) functional unpaired connexons, "hemichannels", on the cell surface. Although these various pathways have been defined, it is not clear how often and to what extent astrocytes employ different mechanisms. It will be necessary to determine whether the same glutamate release mechanisms that operate under physiological conditions operate during pathological conditions or whether there are specific release mechanisms that operate under particular conditions.
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Affiliation(s)
| | - Vladimir Parpura
- Departments of Physics & Astronomy, Centers for Glial-Neuronal Interactions and Nanoscale Science & Engineering, University of California, Riverside, CA 92521
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Jourdain P, Bergersen LH, Bhaukaurally K, Bezzi P, Santello M, Domercq M, Matute C, Tonello F, Gundersen V, Volterra A. Glutamate exocytosis from astrocytes controls synaptic strength. Nat Neurosci 2007; 10:331-9. [PMID: 17310248 DOI: 10.1038/nn1849] [Citation(s) in RCA: 599] [Impact Index Per Article: 35.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2006] [Accepted: 01/16/2007] [Indexed: 01/07/2023]
Abstract
The release of transmitters from glia influences synaptic functions. The modalities and physiological functions of glial release are poorly understood. Here we show that glutamate exocytosis from astrocytes of the rat hippocampal dentate molecular layer enhances synaptic strength at excitatory synapses between perforant path afferents and granule cells. The effect is mediated by ifenprodil-sensitive NMDA ionotropic glutamate receptors and involves an increase of transmitter release at the synapse. Correspondingly, we identify NMDA receptor 2B subunits on the extrasynaptic portion of excitatory nerve terminals. The receptor distribution is spatially related to glutamate-containing synaptic-like microvesicles in the apposed astrocytic processes. This glial regulatory pathway is endogenously activated by neuronal activity-dependent stimulation of purinergic P2Y1 receptors on the astrocytes. Thus, we provide the first combined functional and ultrastructural evidence for a physiological control of synaptic activity via exocytosis of glutamate from astrocytes.
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Affiliation(s)
- Pascal Jourdain
- Department of Cell Biology and Morphology, University of Lausanne, Rue du Bugnon 9, 1005 Lausanne, Switzerland
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Vesce S, Rossi D, Brambilla L, Volterra A. Glutamate release from astrocytes in physiological conditions and in neurodegenerative disorders characterized by neuroinflammation. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2007; 82:57-71. [PMID: 17678955 DOI: 10.1016/s0074-7742(07)82003-4] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
Although glial cells have been traditionally viewed as supportive partners of neurons, studies of the last 20 years demonstrate that astrocytes possess functional receptors for neurotransmitters and other signaling molecules and respond to their stimulation via release of chemical transmitters (called gliotransmitters) such as glutamate, ATP, and d-serine. Notably, astrocytes react to synaptically released neurotransmitters with intracellular calcium ([Ca(2+)](i)) elevations, which result in the release of glutamate via regulated exocytosis and possibly other mechanisms. These findings have led to a new concept of neuron-glia intercommunication where astrocytes play an unsuspected dynamic role by integrating neuronal inputs and modulating synaptic activity. The additional discovery that glutamate release from astrocytes is controlled by molecules linked to inflammatory reactions, such as the cytokine tumor necrosis factor-alpha (TNF-alpha) and prostaglandins, suggests that glia-to-neuron signaling may be sensitive to changes in production of these mediators in pathological conditions. Indeed, a local, parenchymal brain inflammatory reaction (neuroinflammation) characterized by astrocytic and microglial activation has been reported in several neurodegenerative disorders, including Alzheimer's disease and AIDS dementia complex. This transition to a reactive state may be accompanied by a disruption of the cross talk normally occurring between astrocytes and neurons and so contribute to disease development. The findings reported in this chapter suggest that a better comprehension of the glutamatergic interplay between neurons and glia may provide information about normal brain function and also highlight possible molecular targets for therapeutic interventions in pathology.
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Affiliation(s)
- Sabino Vesce
- Department of Cell Biology and Morphology, University of Lausanne, Rue du Bugnon 9, 1005 Lausanne, Switzerland
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Croisier E, Graeber MB. Glial degeneration and reactive gliosis in alpha-synucleinopathies: the emerging concept of primary gliodegeneration. Acta Neuropathol 2006; 112:517-30. [PMID: 16896905 DOI: 10.1007/s00401-006-0119-z] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2006] [Revised: 07/04/2006] [Accepted: 07/04/2006] [Indexed: 01/06/2023]
Abstract
The concept of gliodegenerative diseases has not been widely established although there is accumulating evidence that glial cells may represent a primary target of degenerative disease processes. In the central nervous system (CNS), examples that provide a "proof of concept" include at least one alpha-synucleinopathy, multiple system atrophy (MSA), but this disease is conventionally discussed under the heading of "neurodegeneration". Additional evidence in support of primary glial affection has been reported in neurodegenerative disorders such as Parkinson's disease, Alzheimer's disease and transmissible spongiform encephalopathies. Based on biochemical, genetic and transcriptomic studies it is also becoming increasingly clear that the molecular changes measured in whole tissue extracts, e.g. obtained from Parkinson's disease brain, are not based on a purely neuronal contribution. This important evidence has been missed in cell culture or laser capture work focusing on the neuronal cell population. Studies of animal and in vitro models of disease pathogenesis additionally suggest glial accountability for some CNS degenerative processes. This review provides a critical analysis of the evidence available to date in support of the concept of gliodegeneration, which we propose to represent an essential although largely disregarded component of the spectrum of classical "neurodegeneration". Examples from the spectrum of alpha-synucleinopathies are presented.
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Affiliation(s)
- Emilie Croisier
- University Department of Neuropathology, Imperial College London and Hammersmith Hospitals Trust, Charing Cross Campus, Fulham Palace Road, London, UK
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