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Kim J, Kaang BK. Cyclic AMP response element-binding protein (CREB) transcription factor in astrocytic synaptic communication. Front Synaptic Neurosci 2023; 14:1059918. [PMID: 36685081 PMCID: PMC9845270 DOI: 10.3389/fnsyn.2022.1059918] [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: 10/02/2022] [Accepted: 10/24/2022] [Indexed: 01/05/2023] Open
Abstract
Astrocytes are known to actively participate in synaptic communication by forming structures called tripartite synapses. These synapses consist of presynaptic axon terminals, postsynaptic dendritic spines, and astrocytic processes where astrocytes release and receive transmitters. Although the transcription factor cyclic AMP response element (CRE)-binding protein (CREB) has been actively studied as an important factor for mediating synaptic activity-induced responses in neurons, its role in astrocytes is relatively unknown. Synaptic signals are known to activate various downstream pathways in astrocytes, which can activate the CREB transcription factor. Therefore, there is a need to summarize studies on astrocytic intracellular pathways that are induced by synaptic communication resulting in activation of the CREB pathway. In this review, we discuss the various neurotransmitter receptors and intracellular pathways that can induce CREB activation and CREB-induced gene regulation in astrocytes.
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2
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Olude MA, Mouihate A, Mustapha OA, Farina C, Quintana FJ, Olopade JO. Astrocytes and Microglia in Stress-Induced Neuroinflammation: The African Perspective. Front Immunol 2022; 13:795089. [PMID: 35707531 PMCID: PMC9190229 DOI: 10.3389/fimmu.2022.795089] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Accepted: 04/13/2022] [Indexed: 11/13/2022] Open
Abstract
Background: Africa is laden with a youthful population, vast mineral resources and rich fauna. However, decades of unfortunate historical, sociocultural and leadership challenges make the continent a hotspot for poverty, indoor and outdoor pollutants with attendant stress factors such as violence, malnutrition, infectious outbreaks and psychological perturbations. The burden of these stressors initiate neuroinflammatory responses but the pattern and mechanisms of glial activation in these scenarios are yet to be properly elucidated. Africa is therefore most vulnerable to neurological stressors when placed against a backdrop of demographics that favor explosive childbearing, a vast population of unemployed youths making up a projected 42% of global youth population by 2030, repressive sociocultural policies towards women, poor access to healthcare, malnutrition, rapid urbanization, climate change and pollution. Early life stress, whether physical or psychological, induces neuroinflammatory response in developing nervous system and consequently leads to the emergence of mental health problems during adulthood. Brain inflammatory response is driven largely by inflammatory mediators released by glial cells; namely astrocytes and microglia. These inflammatory mediators alter the developmental trajectory of fetal and neonatal brain and results in long-lasting maladaptive behaviors and cognitive deficits. This review seeks to highlight the patterns and mechanisms of stressors such as poverty, developmental stress, environmental pollutions as well as malnutrition stress on astrocytes and microglia in neuroinflammation within the African context.
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Affiliation(s)
- Matthew Ayokunle Olude
- Vertebrate Morphology, Environmental Toxicology and Neuroscience Unit, College of Veterinary Medicine, Federal University of Agriculture, Abeokuta, Nigeria
- *Correspondence: Matthew Ayokunle Olude,
| | - Abdeslam Mouihate
- Department of Physiology, Faculty of Medicine, Health Sciences Centre, Kuwait University, Kuwait City, Kuwait
| | - Oluwaseun Ahmed Mustapha
- Vertebrate Morphology, Environmental Toxicology and Neuroscience Unit, College of Veterinary Medicine, Federal University of Agriculture, Abeokuta, Nigeria
| | - Cinthia Farina
- Istituto di Ricovero e Cura a Carattere Scientifico (IRCSS) San Raffaele Scientific Institute, Institute of Experimental Neurology (INSPE) and Division of Neuroscience, Milan, Italy
| | - Francisco Javier Quintana
- Ann Romney Center for Neurologic Diseases, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, United States
| | - James Olukayode Olopade
- Neuroscience Unit, Department of Veterinary Anatomy, Faculty of Veterinary Medicine, University of Ibadan, Ibadan, Nigeria
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3
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Human Serine Racemase Weakly Binds the Third PDZ Domain of PSD-95. Int J Mol Sci 2022; 23:ijms23094959. [PMID: 35563349 PMCID: PMC9105370 DOI: 10.3390/ijms23094959] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Revised: 04/13/2022] [Accepted: 04/27/2022] [Indexed: 11/16/2022] Open
Abstract
Human serine racemase (hSR) is a pyridoxal-5'-phosphate (PLP)-dependent dimer that catalyzes the formation of D-serine from L-serine, as well as the dehydration of both L- and D-serine to pyruvate and ammonia. As D-serine is a co-agonist of N-methyl-D-aspartate receptors (NMDARs), hSR is a key enzyme in glutamatergic neurotransmission. hSR activity is finely regulated by Mg2+, ATP, post-translational modifications, and the interaction with protein partners. In particular, the C-terminus of murine SR binds the third PDZ domain (PDZ3) of postsynaptic density protein 95 (PSD-95), a member of the membrane-associated guanylate kinase (MAGUK) family involved in the trafficking and localization of glutamate receptors. The structural details of the interaction and the stability of the complex have not been elucidated yet. We evaluated the binding of recombinant human PSD-95 PDZ3 to hSR by glutaraldehyde cross-linking, pull-down assays, isothermal titration calorimetry, nuclear magnetic resonance, and enzymatic assays. Overall, a weak interaction was observed, confirming the binding for the human orthologs but supporting the hypothesis that a third protein partner (i.e., stargazin) is required for the regulation of hSR activity by PSD-95 and to stabilize their interaction.
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4
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Role of EphA4 in Mediating Motor Neuron Death in MND. Int J Mol Sci 2021; 22:ijms22179430. [PMID: 34502339 PMCID: PMC8430883 DOI: 10.3390/ijms22179430] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Revised: 08/26/2021] [Accepted: 08/26/2021] [Indexed: 11/26/2022] Open
Abstract
Motor neuron disease (MND) comprises a group of fatal neurodegenerative diseases with no effective cure. As progressive motor neuron cell death is one of pathological characteristics of MND, molecules which protect these cells are attractive therapeutic targets. Accumulating evidence indicates that EphA4 activation is involved in MND pathogenesis, and inhibition of EphA4 improves functional outcomes. However, the underlying mechanism of EphA4’s function in MND is unclear. In this review, we first present results to demonstrate that EphA4 signalling acts directly on motor neurons to cause cell death. We then review the three most likely mechanisms underlying this effect.
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5
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Sherwood MW, Oliet SHR, Panatier A. NMDARs, Coincidence Detectors of Astrocytic and Neuronal Activities. Int J Mol Sci 2021; 22:7258. [PMID: 34298875 PMCID: PMC8307462 DOI: 10.3390/ijms22147258] [Citation(s) in RCA: 9] [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: 05/28/2021] [Revised: 06/30/2021] [Accepted: 06/30/2021] [Indexed: 12/18/2022] Open
Abstract
Synaptic plasticity is an extensively studied cellular correlate of learning and memory in which NMDARs play a starring role. One of the most interesting features of NMDARs is their ability to act as a co-incident detector. It is unique amongst neurotransmitter receptors in this respect. Co-incident detection is possible because the opening of NMDARs requires membrane depolarisation and the binding of glutamate. Opening of NMDARs also requires a co-agonist. Although the dynamic regulation of glutamate and membrane depolarization have been well studied in coincident detection, the role of the co-agonist site is unexplored. It turns out that non-neuronal glial cells, astrocytes, regulate co-agonist availability, giving them the ability to influence synaptic plasticity. The unique morphology and spatial arrangement of astrocytes at the synaptic level affords them the capacity to sample and integrate information originating from unrelated synapses, regardless of any pre-synaptic and post-synaptic commonality. As astrocytes are classically considered slow responders, their influence at the synapse is widely recognized as modulatory. The aim herein is to reconsider the potential of astrocytes to participate directly in ongoing synaptic NMDAR activity and co-incident detection.
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Affiliation(s)
- Mark W. Sherwood
- University of Bordeaux, INSERM, Neurocentre Magendie, U1215, F-3300 Bordeaux, France;
| | | | - Aude Panatier
- University of Bordeaux, INSERM, Neurocentre Magendie, U1215, F-3300 Bordeaux, France;
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6
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Clark IC, Gutiérrez-Vázquez C, Wheeler MA, Li Z, Rothhammer V, Linnerbauer M, Sanmarco LM, Guo L, Blain M, Zandee SEJ, Chao CC, Batterman KV, Schwabenland M, Lotfy P, Tejeda-Velarde A, Hewson P, Manganeli Polonio C, Shultis MW, Salem Y, Tjon EC, Fonseca-Castro PH, Borucki DM, Alves de Lima K, Plasencia A, Abate AR, Rosene DL, Hodgetts KJ, Prinz M, Antel JP, Prat A, Quintana FJ. Barcoded viral tracing of single-cell interactions in central nervous system inflammation. Science 2021; 372:372/6540/eabf1230. [PMID: 33888612 DOI: 10.1126/science.abf1230] [Citation(s) in RCA: 123] [Impact Index Per Article: 41.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Revised: 01/27/2021] [Accepted: 03/12/2021] [Indexed: 12/11/2022]
Abstract
Cell-cell interactions control the physiology and pathology of the central nervous system (CNS). To study astrocyte cell interactions in vivo, we developed rabies barcode interaction detection followed by sequencing (RABID-seq), which combines barcoded viral tracing and single-cell RNA sequencing (scRNA-seq). Using RABID-seq, we identified axon guidance molecules as candidate mediators of microglia-astrocyte interactions that promote CNS pathology in experimental autoimmune encephalomyelitis (EAE) and, potentially, multiple sclerosis (MS). In vivo cell-specific genetic perturbation EAE studies, in vitro systems, and the analysis of MS scRNA-seq datasets and CNS tissue established that Sema4D and Ephrin-B3 expressed in microglia control astrocyte responses via PlexinB2 and EphB3, respectively. Furthermore, a CNS-penetrant EphB3 inhibitor suppressed astrocyte and microglia proinflammatory responses and ameliorated EAE. In summary, RABID-seq identified microglia-astrocyte interactions and candidate therapeutic targets.
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Affiliation(s)
- Iain C Clark
- Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA.,Department of Bioengineering, University of California, Berkeley, California Institute for Quantitative Biosciences, Berkeley, CA 94720, USA
| | - Cristina Gutiérrez-Vázquez
- Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Michael A Wheeler
- Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA.,Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Zhaorong Li
- Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA.,Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Veit Rothhammer
- Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA.,Department of Neurology, University Hospital Erlangen, Friedrich-Alexander University Erlangen-Nürnberg, 91054 Erlangen, Germany
| | - Mathias Linnerbauer
- Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA.,Department of Neurology, University Hospital Erlangen, Friedrich-Alexander University Erlangen-Nürnberg, 91054 Erlangen, Germany
| | - Liliana M Sanmarco
- Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Lydia Guo
- Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Manon Blain
- Neuroimmunology Unit, Montreal Neurological Institute, Department of Neurology and Neurosurgery, McGill University, Montreal, QC H3A 2B4, Canada
| | - Stephanie E J Zandee
- Neuroimmunology Research Laboratory, Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montreal, QC H2X 0A9, Canada
| | - Chun-Cheih Chao
- Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Katelyn V Batterman
- Department of Anatomy and Neurobiology, Boston University School of Medicine, Boston, MA 02118, USA
| | - Marius Schwabenland
- Institute of Neuropathology, University of Freiburg, D-79106 Freiburg, Germany
| | - Peter Lotfy
- Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA.,Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Amalia Tejeda-Velarde
- Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Patrick Hewson
- Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Carolina Manganeli Polonio
- Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Michael W Shultis
- Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Yasmin Salem
- Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Emily C Tjon
- Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Pedro H Fonseca-Castro
- Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Davis M Borucki
- Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Kalil Alves de Lima
- Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Agustin Plasencia
- Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Adam R Abate
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, California Institute for Quantitative Biosciences, San Francisco, CA 94158, USA.,Chan Zuckerberg Biohub, San Francisco, CA, USA
| | - Douglas L Rosene
- Department of Anatomy and Neurobiology, Boston University School of Medicine, Boston, MA 02118, USA
| | - Kevin J Hodgetts
- Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Marco Prinz
- Institute of Neuropathology, University of Freiburg, D-79106 Freiburg, Germany.,Signaling Research Centres BIOSS and CIBSS, University of Freiburg, D-79106 Freiburg, Germany.,Center for Basics in NeuroModulation (NeuroModulBasics), Faculty of Medicine, University of Freiburg, D-79106 Freiburg, Germany
| | - Jack P Antel
- Neuroimmunology Unit, Montreal Neurological Institute, Department of Neurology and Neurosurgery, McGill University, Montreal, QC H3A 2B4, Canada
| | - Alexandre Prat
- Neuroimmunology Research Laboratory, Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montreal, QC H2X 0A9, Canada
| | - Francisco J Quintana
- Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA. .,Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
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7
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Tan CX, Eroglu C. Cell adhesion molecules regulating astrocyte-neuron interactions. Curr Opin Neurobiol 2021; 69:170-177. [PMID: 33957433 DOI: 10.1016/j.conb.2021.03.015] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Revised: 03/23/2021] [Accepted: 03/24/2021] [Indexed: 12/15/2022]
Abstract
A tripartite synapse comprises a neuronal presynaptic axon and a postsynaptic dendrite, which are closely ensheathed by a perisynaptic astrocyte process. Through their structural and functional association with thousands of neuronal synapses, astrocytes regulate synapse formation and function. Recent work revealed a diverse range of cell adhesion-based mechanisms that mediate astrocyte-synapse interactions at tripartite synapses. Here, we will review some of these findings unveiling a highly dynamic bidirectional signaling between astrocytes and synapses, which orchestrates astrocyte morphological maturation and synapse development. Moreover, we will discuss the roles of these newly discovered molecular pathways in brain physiology and function both in health and disease.
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Affiliation(s)
- Christabel X Tan
- Department of Cell Biology, Duke University Medical Center, Durham, NC, 27710, USA
| | - Cagla Eroglu
- Department of Cell Biology, Duke University Medical Center, Durham, NC, 27710, USA; Department of Neurobiology, Duke University Medical Center, Durham, NC, 27710, USA; Duke Institute for Brain Sciences, Durham, NC, 27710, USA; Regeneration Next Initiative, Duke University, Durham, NC, 27710, USA.
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8
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Abstract
Astrocytes are the most abundant glial cells in the mammalian brain and directly participate in the proper functioning of the nervous system by regulating ion homeostasis, controlling glutamate reuptake, and maintaining the blood-brain barrier. In the last two decades, a growing body of work also identified critical roles for astrocytes in regulating synaptic connectivity. Stemming from the observation that functional and morphological development of astrocytes occur concurrently with synapse formation and maturation, these studies revealed that both developmental processes are directly linked. In fact, astrocytes both physically contact numerous synaptic structures and actively instruct many aspects of synaptic development and function via a plethora of secreted and adhesion-based molecular signals. The complex astrocyte-to-neuron signaling modalities control different stages of synaptic development such as regulating the initial formation of structural synapses as well as their functional maturation. Furthermore, the synapse-modulating functions of astrocytes are evolutionarily conserved and contribute to the development and plasticity of diverse classes of synapses and circuits throughout the central nervous system. Importantly, because impaired synapse formation and function is a hallmark of many neurodevelopmental disorders, deficits in astrocytes are likely to be major contributors to disease pathogenesis. In this chapter, we review our current understanding of the cellular and molecular mechanisms by which astrocytes contribute to synapse development and discuss the bidirectional secretion-based and contact-mediated mechanisms responsible for these essential developmental processes.
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Affiliation(s)
- Christabel X Tan
- Department of Cell Biology, Duke University Medical Center, Durham, NC, United States
| | - Caley J Burrus Lane
- Department of Cell Biology, Duke University Medical Center, Durham, NC, United States; Department of Neurobiology, Duke University Medical Center, Durham, NC, United States
| | - Cagla Eroglu
- Department of Cell Biology, Duke University Medical Center, Durham, NC, United States; Department of Neurobiology, Duke University Medical Center, Durham, NC, United States; Duke Institute for Brain Sciences, Durham, NC, United States; Regeneration Next Initiative, Duke University, Durham, NC, United States.
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9
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Verhoog QP, Holtman L, Aronica E, van Vliet EA. Astrocytes as Guardians of Neuronal Excitability: Mechanisms Underlying Epileptogenesis. Front Neurol 2020; 11:591690. [PMID: 33324329 PMCID: PMC7726323 DOI: 10.3389/fneur.2020.591690] [Citation(s) in RCA: 73] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Accepted: 10/26/2020] [Indexed: 12/11/2022] Open
Abstract
Astrocytes are key homeostatic regulators in the central nervous system and play important roles in physiology. After brain damage caused by e.g., status epilepticus, traumatic brain injury, or stroke, astrocytes may adopt a reactive phenotype. This process of reactive astrogliosis is important to restore brain homeostasis. However, persistent reactive astrogliosis can be detrimental for the brain and contributes to the development of epilepsy. In this review, we will focus on physiological functions of astrocytes in the normal brain as well as pathophysiological functions in the epileptogenic brain, with a focus on acquired epilepsy. We will discuss the role of astrocyte-related processes in epileptogenesis, including reactive astrogliosis, disturbances in energy supply and metabolism, gliotransmission, and extracellular ion concentrations, as well as blood-brain barrier dysfunction and dysregulation of blood flow. Since dysfunction of astrocytes can contribute to epilepsy, we will also discuss their role as potential targets for new therapeutic strategies.
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Affiliation(s)
- Quirijn P. Verhoog
- Leiden Academic Center for Drug Research, Leiden University, Leiden, Netherlands
- Department of Neuropathology, Amsterdam Neuroscience, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
| | - Linda Holtman
- Leiden Academic Center for Drug Research, Leiden University, Leiden, Netherlands
| | - Eleonora Aronica
- Department of Neuropathology, Amsterdam Neuroscience, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
- Stichting Epilepsie Instellingen Nederland (SEIN), Heemstede, Netherlands
| | - Erwin A. van Vliet
- Department of Neuropathology, Amsterdam Neuroscience, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
- Center for Neuroscience, Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, Netherlands
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10
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Zhao J, Taylor CJ, Newcombe EA, Spanevello MD, O'Keeffe I, Cooper LT, Jhaveri DJ, Boyd AW, Bartlett PF. EphA4 Regulates Hippocampal Neural Precursor Proliferation in the Adult Mouse Brain by d-Serine Modulation of N-Methyl-d-Aspartate Receptor Signaling. Cereb Cortex 2020; 29:4381-4397. [PMID: 30590507 DOI: 10.1093/cercor/bhy319] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Revised: 11/20/2018] [Accepted: 11/22/2018] [Indexed: 12/14/2022] Open
Abstract
The hippocampal dentate gyrus (DG) is a major region of the adult rodent brain in which neurogenesis occurs throughout life. The EphA4 receptor, which regulates neurogenesis and boundary formation in the developing brain, is also expressed in the adult DG, but whether it regulates adult hippocampal neurogenesis is not known. Here, we show that, in the adult mouse brain, EphA4 inhibits hippocampal precursor cell proliferation but does not affect precursor differentiation or survival. Genetic deletion or pharmacological inhibition of EphA4 significantly increased hippocampal precursor proliferation in vivo and in vitro, by blocking EphA4 forward signaling. EphA4 was expressed by mature hippocampal DG neurons but not neural precursor cells, and an EphA4 antagonist, EphA4-Fc, did not activate clonal cultures of precursors until they were co-cultured with non-precursor cells, indicating an indirect effect of EphA4 on the regulation of precursor activity. Supplementation with d-serine blocked the increased precursor proliferation induced by EphA4 inhibition, whereas blocking the interaction between d-serine and N-methyl-d-aspartate receptors (NMDARs) promoted precursor activity, even at the clonal level. Collectively, these findings demonstrate that EphA4 indirectly regulates adult hippocampal precursor proliferation and thus plays a role in neurogenesis via d-serine-regulated NMDAR signaling.
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Affiliation(s)
- Jing Zhao
- Queensland Brain Institute, The University of Queensland, St Lucia, QLD, Australia
| | - Chanel J Taylor
- Queensland Brain Institute, The University of Queensland, St Lucia, QLD, Australia
| | - Estella A Newcombe
- Queensland Brain Institute, The University of Queensland, St Lucia, QLD, Australia
| | - Mark D Spanevello
- Queensland Brain Institute, The University of Queensland, St Lucia, QLD, Australia
| | - Imogen O'Keeffe
- Queensland Brain Institute, The University of Queensland, St Lucia, QLD, Australia
| | - Leanne T Cooper
- Queensland Brain Institute, The University of Queensland, St Lucia, QLD, Australia.,QIMR Berghofer Medical Research Institute, St Lucia, QLD, Australia
| | - Dhanisha J Jhaveri
- Queensland Brain Institute, The University of Queensland, St Lucia, QLD, Australia.,Mater Research Institute, The University of Queensland, Brisbane, QLD, Australia
| | - Andrew W Boyd
- QIMR Berghofer Medical Research Institute, St Lucia, QLD, Australia.,School of Medicine, The University of Queensland, St Lucia, QLD, Australia
| | - Perry F Bartlett
- Queensland Brain Institute, The University of Queensland, St Lucia, QLD, Australia
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11
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D-Serine, the Shape-Shifting NMDA Receptor Co-agonist. Neurochem Res 2020; 45:1344-1353. [PMID: 32189130 DOI: 10.1007/s11064-020-03014-1] [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: 01/29/2020] [Revised: 03/04/2020] [Accepted: 03/11/2020] [Indexed: 12/17/2022]
Abstract
Shape-shifting, a phenomenon wide-spread in folklore, refers to the ability to physically change from one identity to another, typically from an innocuous entity to a destructive one. The amino acid D-serine over the last 25 years has "shape-shifted" into several identities: a purported glial transmitter activating N-methyl-D-aspartate receptors (NMDARs), a co-transmitter concentrated in excitatory glutamatergic neurons, an autocrine that is released at dendritic spines to prime their post-synaptic NMDARs for an instantaneous response to glutamate and an excitotoxic moiety released from inflammatory (A1) astrocytes. This article will review evidence in support of these scenarios and the artifacts that misled investigators of the true identity of D-serine.
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12
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Gordleeva SY, Ermolaeva AV, Kastalskiy IA, Kazantsev VB. Astrocyte as Spatiotemporal Integrating Detector of Neuronal Activity. Front Physiol 2019; 10:294. [PMID: 31057412 PMCID: PMC6482266 DOI: 10.3389/fphys.2019.00294] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2018] [Accepted: 03/06/2019] [Indexed: 11/21/2022] Open
Abstract
The functional role of astrocyte calcium signaling in brain information processing was intensely debated in recent decades. This interest was motivated by high resolution imaging techniques showing highly developed structure of distal astrocyte processes. Another point was the evidence of bi-directional astrocytic regulation of neuronal activity. To analyze the effects of interplay of calcium signals in processes and in soma mediating correlations between local signals and the cell-level response of the astrocyte we proposed spatially extended model of the astrocyte calcium dynamics. Specifically, we investigated how spatiotemporal properties of Ca2+ dynamics in spatially extended astrocyte model can coordinate (e.g., synchronize) networks of neurons and synapses.
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Affiliation(s)
- Susan Yu Gordleeva
- Department of Neurotechnology, Lobachevsky State University, Nizhny Novgorod, Russia
| | - Anastasia V Ermolaeva
- Department of Neurotechnology, Lobachevsky State University, Nizhny Novgorod, Russia
| | | | - Victor B Kazantsev
- Department of Neurotechnology, Lobachevsky State University, Nizhny Novgorod, Russia
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13
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Multiple Lines of Evidence Indicate That Gliotransmission Does Not Occur under Physiological Conditions. J Neurosci 2019; 38:3-13. [PMID: 29298904 DOI: 10.1523/jneurosci.0016-17.2017] [Citation(s) in RCA: 126] [Impact Index Per Article: 25.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2017] [Revised: 09/01/2017] [Accepted: 10/02/2017] [Indexed: 12/22/2022] Open
Abstract
A major controversy persists within the field of glial biology concerning whether or not, under physiological conditions, neuronal activity leads to Ca2+-dependent release of neurotransmitters from astrocytes, a phenomenon known as gliotransmission. Our perspective is that, while we and others can apply techniques to cause gliotransmission, there is considerable evidence gathered using astrocyte-specific and more physiological approaches which suggests that gliotransmission is a pharmacological phenomenon rather than a physiological process. Approaches providing evidence against gliotransmission include stimulation of Gq-GPCRs expressed only in astrocytes, as well as removal of the primary proposed source of astrocyte Ca2+ responsible for gliotransmission. These approaches contrast with those supportive of gliotransmission, which include mechanical stimulation, strong astrocytic depolarization using whole-cell patch-clamp or optogenetics, uncaging Ca2+ or IP3, chelating Ca2+ using BAPTA, and nonspecific bath application of agonists to receptors expressed by a multitude of cell types. These techniques are not subtle and therefore are not supportive of recent suggestions that gliotransmission requires very specific and delicate temporal and spatial requirements. Other evidence, including lack of propagating Ca2+ waves between astrocytes in healthy tissue, lack of expression of vesicular release machinery, and the demise of the d-serine gliotransmission hypothesis, provides additional evidence against gliotransmission. Overall, the data suggest that Ca2+-dependent release of neurotransmitters is the province of neurons, not astrocytes, in the intact brain under physiological conditions.Dual Perspectives Companion Paper: Gliotransmission: Beyond Black-and-White, by Iaroslav Savtchouk and Andrea Volterra.
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14
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Qi L, Cui EH, Ji CM, Zhang XB, Wang ZA, Sun YZ, Xu JC, Zhai XF, Chen ZJ, Li J, Zheng JY, Yu RT. Specific knockdown of hippocampal astroglial EphB2 improves synaptic function via inhibition of D-serine secretion in APP/PS1 mice. Am J Transl Res 2019; 11:1073-1083. [PMID: 30899407 PMCID: PMC6413293] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2018] [Accepted: 12/18/2018] [Indexed: 06/09/2023]
Abstract
Increasing evidence emphasizes the protective role of Eph receptors in synaptic function in the pathological development of Alzheimer's disease (AD); however, their roles in the regulation of hippocampal astrocytes remain largely unknown. Here, we directly investigated the function of astroglial EphB2 on synaptic plasticity in APP/PS1 mice. Using cell isolation and transgene technologies, we first isolated hippocampal astrocytes and evaluated the expression levels of ephrinB ligands and EphB receptors. Then, we stereotaxically injected EphB2-Flox-AAV into the hippocampus of GFAP-cre/APP/PS1 mice and further evaluated hippocampal synaptic plasticity and astroglial function. Interestingly, astrocytic EphB2 expression was significantly increased in APP/PS1 mice in contrast to its expression profile in neurons. Moreover, depressing this astroglial EphB2 upregulation enhanced hippocampal synaptic plasticity, which results from harmful D-serine release. These results provide evidence of the different expression profiles and function of EphB2 between astrocytes and neurons in AD pathology.
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Affiliation(s)
- Liang Qi
- Xuzhou Medical UniversityXuzhou, Jiangsu, China
| | - En-Hui Cui
- Department of Anesthesiology, Huai’an Matenal and Child Health HospitalHuai’an, Jiangsu, China
| | - Chun-Mei Ji
- Department of Neurosurgery, Huai’an Second People’s Hospital and The Affiliated Huai’an Hospital of Xuzhou Medical UniversityHuai’an, Jiangsu, China
| | - Xiao-Bing Zhang
- Department of Neurosurgery, Huai’an Second People’s Hospital and The Affiliated Huai’an Hospital of Xuzhou Medical UniversityHuai’an, Jiangsu, China
| | - Ze-Ai Wang
- Department of Neurosurgery, Huai’an Second People’s Hospital and The Affiliated Huai’an Hospital of Xuzhou Medical UniversityHuai’an, Jiangsu, China
| | - Yuan-Zhao Sun
- Department of Neurosurgery, Huai’an Second People’s Hospital and The Affiliated Huai’an Hospital of Xuzhou Medical UniversityHuai’an, Jiangsu, China
| | - Jian-Chang Xu
- Department of Neurosurgery, Huai’an Second People’s Hospital and The Affiliated Huai’an Hospital of Xuzhou Medical UniversityHuai’an, Jiangsu, China
| | - Xiao-Fu Zhai
- Department of Neurosurgery, Huai’an Second People’s Hospital and The Affiliated Huai’an Hospital of Xuzhou Medical UniversityHuai’an, Jiangsu, China
| | - Zhong-Jun Chen
- Department of Neurosurgery, Huai’an Second People’s Hospital and The Affiliated Huai’an Hospital of Xuzhou Medical UniversityHuai’an, Jiangsu, China
| | - Jing Li
- Department of Neurosurgery, Huai’an Second People’s Hospital and The Affiliated Huai’an Hospital of Xuzhou Medical UniversityHuai’an, Jiangsu, China
| | - Jin-Yu Zheng
- Department of Neurosurgery, Huai’an Second People’s Hospital and The Affiliated Huai’an Hospital of Xuzhou Medical UniversityHuai’an, Jiangsu, China
| | - Ru-Tong Yu
- Laboratory of Neurosurgery, Xuzhou Medical UniversityXuzhou, Jiangsu, China
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15
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Raboni S, Marchetti M, Faggiano S, Campanini B, Bruno S, Marchesani F, Margiotta M, Mozzarelli A. The Energy Landscape of Human Serine Racemase. Front Mol Biosci 2019; 5:112. [PMID: 30687716 PMCID: PMC6333871 DOI: 10.3389/fmolb.2018.00112] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Accepted: 11/26/2018] [Indexed: 12/17/2022] Open
Abstract
Human serine racemase is a pyridoxal 5′-phosphate (PLP)-dependent dimeric enzyme that catalyzes the reversible racemization of L-serine and D-serine and their dehydration to pyruvate and ammonia. As D-serine is the co-agonist of the N-methyl-D-aspartate receptors for glutamate, the most abundant excitatory neurotransmitter in the brain, the structure, dynamics, function, regulation and cellular localization of serine racemase have been investigated in detail. Serine racemase belongs to the fold-type II of the PLP-dependent enzyme family and structural models from several orthologs are available. The comparison of structures of serine racemase co-crystallized with or without ligands indicates the presence of at least one open and one closed conformation, suggesting that conformational flexibility plays a relevant role in enzyme regulation. ATP, Mg2+, Ca2+, anions, NADH and protein interactors, as well as the post-translational modifications nitrosylation and phosphorylation, finely tune the racemase and dehydratase activities and their relative reaction rates. Further information on serine racemase structure and dynamics resulted from the search for inhibitors with potential therapeutic applications. The cumulative knowledge on human serine racemase allowed obtaining insights into its conformational landscape and into the mechanisms of cross-talk between the effector binding sites and the active site.
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Affiliation(s)
- Samanta Raboni
- Department of Food and Drug, University of Parma, Parma, Italy
| | | | - Serena Faggiano
- Department of Food and Drug, University of Parma, Parma, Italy.,Institute of Biophysics, National Research Council, Pisa, Italy
| | | | - Stefano Bruno
- Department of Food and Drug, University of Parma, Parma, Italy
| | | | | | - Andrea Mozzarelli
- Department of Food and Drug, University of Parma, Parma, Italy.,Institute of Biophysics, National Research Council, Pisa, Italy.,National Institute of Biostructures and Biosystems, Rome, Italy
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16
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Human carbonic anhydrase-8 AAV8 gene therapy inhibits nerve growth factor signaling producing prolonged analgesia and anti-hyperalgesia in mice. Gene Ther 2018; 25:297-311. [PMID: 29789638 PMCID: PMC6063772 DOI: 10.1038/s41434-018-0018-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Revised: 01/16/2018] [Accepted: 02/15/2018] [Indexed: 01/02/2023]
Abstract
Carbonic anhydrase-8 (Car8; murine gene symbol) is an allosteric inhibitor of inositol trisphosphate receptor-1 (ITPR1), which regulates neuronal intracellular calcium release. We previously reported that wildtype Car8 overexpression corrects the baseline allodynia and hyperalgesia associated with calcium dysregulation in the waddle (wdl) mouse due to a 19 bp deletion in exon 8 of the Car8 gene. In this report, we provide preliminary evidence that overexpression of the human wildtype ortholog of Car8 (CA8WT), but not the reported CA8 S100P loss-of-function mutation (CA8MT); inhibits nerve growth factor (NGF)-induced phosphorylation of ITPR1, TrkA (NGF high affinity receptor); and ITPR1-mediated cytoplasmic free calcium release in vitro. Additionally, we show that gene-transfer using AAV8-V5-CA8WT viral particles via sciatic nerve injection demonstrates retrograde transport to dorsal root ganglia (DRG) producing prolonged V5-CA8WT expression, pITPR1 and pTrkA inhibition, and profound analgesia and anti-hyperalgesia in male C57BL/6J mice. AAV8-V5-CA8WT mediated overexpression prevented and treated allodynia and hyperalgesia associated with chronic neuropathic pain produced by the spinal nerve ligation (SNL) model. These AAV8-V5-CA8 data provide a proof-of-concept for precision medicine through targeted gene therapy of NGF-responsive somatosensory neurons as a long-acting local analgesic able to prevent and treat chronic neuropathic pain through regulating TrkA signaling, ITPR1 activation, and intracellular free calcium release by ITPR1.
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17
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Hillen AEJ, Burbach JPH, Hol EM. Cell adhesion and matricellular support by astrocytes of the tripartite synapse. Prog Neurobiol 2018; 165-167:66-86. [PMID: 29444459 DOI: 10.1016/j.pneurobio.2018.02.002] [Citation(s) in RCA: 68] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Revised: 07/25/2017] [Accepted: 02/07/2018] [Indexed: 12/18/2022]
Abstract
Astrocytes contribute to the formation, function, and plasticity of synapses. Their processes enwrap the neuronal components of the tripartite synapse, and due to this close interaction they are perfectly positioned to modulate neuronal communication. The interaction between astrocytes and synapses is facilitated by cell adhesion molecules and matricellular proteins, which have been implicated in the formation and functioning of tripartite synapses. The importance of such neuron-astrocyte integration at the synapse is underscored by the emerging role of astrocyte dysfunction in synaptic pathologies such as autism and schizophrenia. Here we review astrocyte-expressed cell adhesion molecules and matricellular molecules that play a role in integration of neurons and astrocytes within the tripartite synapse.
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Affiliation(s)
- Anne E J Hillen
- Department of Translational Neuroscience, Brain Center Rudolf Magnus, University Medical Center Utrecht, 3584 CG Utrecht, The Netherlands; Department of Pediatrics/Child Neurology, VU University Medical Center, 1081 HV Amsterdam, The Netherlands
| | - J Peter H Burbach
- Department of Translational Neuroscience, Brain Center Rudolf Magnus, University Medical Center Utrecht, 3584 CG Utrecht, The Netherlands
| | - Elly M Hol
- Department of Translational Neuroscience, Brain Center Rudolf Magnus, University Medical Center Utrecht, 3584 CG Utrecht, The Netherlands; Swammerdam Institute for Life Sciences, Center for Neuroscience, University of Amsterdam, 1098 XH Amsterdam, The Netherlands; Department of Neuroimmunology, Netherlands Institute for Neuroscience, An Institute of the Royal Netherlands Academy of Arts and Sciences, 1105 BA Amsterdam, The Netherlands.
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18
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Marchesani F, Bruno S, Paredi G, Raboni S, Campanini B, Mozzarelli A. Human serine racemase is nitrosylated at multiple sites. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2018; 1866:813-821. [PMID: 29410194 DOI: 10.1016/j.bbapap.2018.01.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Revised: 01/18/2018] [Accepted: 01/29/2018] [Indexed: 11/26/2022]
Abstract
Serine racemase is a pyridoxal 5'‑phosphate dependent enzyme responsible for the synthesis of d‑serine, a neuromodulator of the NMDA receptors. Its activity is modulated by several ligands, including ATP, divalent cations and protein interactors. The murine orthologue is inhibited by S-nitrosylation at Cys113, a residue adjacent to the ATP binding site. We found that the time course of inhibition of human serine racemase by S-nitrosylation is markedly biphasic, with a fast phase associated with the reaction of Cys113. Unlike the murine enzyme, two additional cysteine residues, Cys269, unique to the human orthologue, and Cys128 were also recognized as S-nitrosylation sites through mass spectrometry and site-directed mutagenesis. The effect of S-nitrosylation on the fluorescence of tryptophan residues and on that of the pyridoxal phosphate cofactor indicated that S-nitrosylation produces a partial interruption of the cross-talk between the ATP binding site and the active site. Overall, it appears that the inhibition results from a conformational change rather than the direct displacement of ATP.
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Affiliation(s)
- Francesco Marchesani
- Dipartimento di Scienze degli Alimenti e del Farmaco, Università di Parma, Parma, Italy
| | - Stefano Bruno
- Dipartimento di Scienze degli Alimenti e del Farmaco, Università di Parma, Parma, Italy.
| | - Gianluca Paredi
- Dipartimento di Scienze degli Alimenti e del Farmaco, Università di Parma, Parma, Italy
| | - Samanta Raboni
- Dipartimento di Scienze degli Alimenti e del Farmaco, Università di Parma, Parma, Italy
| | - Barbara Campanini
- Dipartimento di Scienze degli Alimenti e del Farmaco, Università di Parma, Parma, Italy
| | - Andrea Mozzarelli
- Dipartimento di Scienze degli Alimenti e del Farmaco, Università di Parma, Parma, Italy; Istituto di Biofisica, Consiglio Nazionale delle Ricerche, Pisa, Italy
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19
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Assis-Nascimento P, Tsenkina Y, Liebl DJ. EphB3 signaling induces cortical endothelial cell death and disrupts the blood-brain barrier after traumatic brain injury. Cell Death Dis 2018; 9:7. [PMID: 29311672 PMCID: PMC5849033 DOI: 10.1038/s41419-017-0016-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Revised: 09/20/2017] [Accepted: 10/03/2017] [Indexed: 12/14/2022]
Abstract
Damage to the cerebrovascular network is a major contributor to dysfunction in patients suffering from traumatic brain injury (TBI). Vessels are composed of lumen-forming endothelial cells that associate closely with both glial and neuronal units to establish a functional blood–brain barrier (BBB). Under normal physiological conditions, these vascular units play important roles in central nervous system (CNS) homeostasis by delivering oxygen and nutrients while filtering out molecules and cells that could be harmful; however, after TBI this system is disrupted. Here, we describe a novel role for a class of receptors, called dependence receptors, in regulating vessel stability and BBB integrity after CCI injury in mice. Specifically, we identified that EphB3 receptors function as a pro-apoptotic dependence receptor in endothelial cells (ECs) that contributes to increased BBB damage after CCI injury. In the absence of EphB3, we observed increased endothelial cell survival, reduced BBB permeability and enhanced interactions of astrocyte-EC membranes. Interestingly, the brain’s response to CCI injury is to reduce EphB3 levels and its ligand ephrinB3; however, the degree and timing of those reductions limit the protective response of the CNS. We conclude that EphB3 is a negative regulator of cell survival and BBB integrity that undermine tissue repair, and represents a protective therapeutic target for TBI patients.
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Affiliation(s)
- Poincyane Assis-Nascimento
- The Miami Project to Cure Paralysis, Department of Neurological surgery, University of Miami Miller School of Medicine, 1095 NW 14th Terrace, R-48, Miami, FL, 33136, USA
| | - Yanina Tsenkina
- The Miami Project to Cure Paralysis, Department of Neurological surgery, University of Miami Miller School of Medicine, 1095 NW 14th Terrace, R-48, Miami, FL, 33136, USA
| | - Daniel J Liebl
- The Miami Project to Cure Paralysis, Department of Neurological surgery, University of Miami Miller School of Medicine, 1095 NW 14th Terrace, R-48, Miami, FL, 33136, USA.
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20
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Coyle JT, Balu DT. The Role of Serine Racemase in the Pathophysiology of Brain Disorders. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2017; 82:35-56. [PMID: 29413527 PMCID: PMC5821497 DOI: 10.1016/bs.apha.2017.10.002] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The N-methyl-d-aspartate receptor (NMDAR) is unique in requiring two agonists to bind simultaneously to open its cation channel: the neurotransmitter, glutamate, and the coagonists, glycine, or d-serine. The Snyder laboratory was the first to clone serine racemase (SR), the enzyme that synthesizes d-serine, and to localize it immunocytochemically. Our laboratory has focused on the role of d-serine in brain disorders. Silencing the expression of SR, a risk gene for schizophrenia (SCZ), in mice (SR-/-), results in a phenotype that closely resembles SCZ including: cortical atrophy, reduced dendritic spine density and complexity, downregulation of parvalbumin-positive cortical GABAergic neurons, and cognitive impairments. This pathology can be reversed by treatment of SR-/- mice with d-serine in adulthood. SR-/- mice also exhibit abnormal response toward abusable substances, such as stimulants. They show reduced behavioral sensitization to d-amphetamine, but fail to extinguish it. Place preference to cocaine is altered, and the hedonic response to it is profoundly impaired as assessed by intracranial self-stimulation. d-cycloserine, a partial agonist at the NMDAR glycine modulatory site, shows therapeutic benefit for treating pathologic anxiety in combination with behavioral therapies. Studies in vitro with cortical culture and in vivo with middle cerebral artery occlusion show that silencing SR provides substantial protection against ischemic neuronal death. Finally, the switch of SR expression from neurons to reactive astrocytes after closed head trauma accounts for the reduced in vivo neuroplasticity, electroencephalogram abnormalities, and cognitive impairments.
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Affiliation(s)
- Joseph T Coyle
- Harvard Medical School, Boston, MA, United States; McLean Hospital, Belmont, MA, United States.
| | - Darrick T Balu
- Harvard Medical School, Boston, MA, United States; McLean Hospital, Belmont, MA, United States
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21
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Yang B, Li W, Satani N, Nghiem DM, Xi X, Aronowski J, Savitz SI. Protective Effects of Autologous Bone Marrow Mononuclear Cells After Administering t-PA in an Embolic Stroke Model. Transl Stroke Res 2017; 9:135-145. [PMID: 28836238 DOI: 10.1007/s12975-017-0563-1] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Revised: 08/09/2017] [Accepted: 08/10/2017] [Indexed: 10/19/2022]
Abstract
Tissue plasminogen activator (t-PA) is the only FDA-approved drug for acute ischemic stroke but poses risk for hemorrhagic transformation (HT). Cell therapy has been investigated as a potential therapy to improve recovery after stroke by the modulation of inflammatory responses and the improvement of blood-brain barrier (BBB) integrity, both of which are associated with HT after t-PA. In our present study, we studied the effect of autologous bone marrow mononuclear cells (MNCs) in an embolic stroke model. We administered MNCs in a rat embolic stroke 2 h after administering t-PA. We observed that even though autologous MNCs did not alter the incidence of HT, they decreased the severity of HT and reduced BBB permeability. One possible mechanism could be through the inhibition of MMP3 released by astrocytes via JAK/STAT pathway as shown by our in vitro cell interaction studies.
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Affiliation(s)
- Bing Yang
- Institute for Stroke and Cerebrovascular Disease and Department of Neurology, McGovern Medical School, University of Texas Health Science Center (UTHealth) at Houston, Houston, 77030, TX, USA.
| | - Weilang Li
- Department of Neurology, Tongde Hospital of Zhejiang Province, Hangzhou, China
| | - Nikunj Satani
- Institute for Stroke and Cerebrovascular Disease and Department of Neurology, McGovern Medical School, University of Texas Health Science Center (UTHealth) at Houston, Houston, 77030, TX, USA
| | - Duyen M Nghiem
- Institute for Stroke and Cerebrovascular Disease and Department of Neurology, McGovern Medical School, University of Texas Health Science Center (UTHealth) at Houston, Houston, 77030, TX, USA
| | - XiaoPei Xi
- Institute for Stroke and Cerebrovascular Disease and Department of Neurology, McGovern Medical School, University of Texas Health Science Center (UTHealth) at Houston, Houston, 77030, TX, USA
| | - Jaroslaw Aronowski
- Institute for Stroke and Cerebrovascular Disease and Department of Neurology, McGovern Medical School, University of Texas Health Science Center (UTHealth) at Houston, Houston, 77030, TX, USA
| | - Sean I Savitz
- Institute for Stroke and Cerebrovascular Disease and Department of Neurology, McGovern Medical School, University of Texas Health Science Center (UTHealth) at Houston, Houston, 77030, TX, USA
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22
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Perez EJ, Cepero ML, Perez SU, Coyle JT, Sick TJ, Liebl DJ. EphB3 signaling propagates synaptic dysfunction in the traumatic injured brain. Neurobiol Dis 2016; 94:73-84. [PMID: 27317833 PMCID: PMC5662938 DOI: 10.1016/j.nbd.2016.06.007] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2016] [Revised: 05/25/2016] [Accepted: 06/14/2016] [Indexed: 12/25/2022] Open
Abstract
Traumatic brain injury (TBI), ranging from mild concussion to severe penetrating wounds, can involve brain regions that contain damaged or lost synapses in the absence of neuronal death. These affected regions significantly contribute to sensory, motor and/or cognitive deficits. Thus, studying the mechanisms responsible for synaptic instability and dysfunction is important for protecting the nervous system from the consequences of progressive TBI. Our controlled cortical impact (CCI) injury produces ~20% loss of synapses and mild changes in synaptic protein levels in the CA3-CA1 hippocampus without neuronal losses. These synaptic changes are associated with functional deficits, indicated by >50% loss in synaptic plasticity and impaired learning behavior. We show that the receptor tyrosine kinase EphB3 participates in CCI injury-induced synaptic damage, where EphB3(-/-) mice show preserved long-term potentiation and hippocampal-dependent learning behavior as compared with wild type (WT) injured mice. Improved synaptic function in the absence of EphB3 results from attenuation in CCI injury-induced synaptic losses and reduced d-serine levels compared with WT injured mice. Together, these findings suggest that EphB3 signaling plays a deleterious role in synaptic stability and plasticity after TBI.
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Affiliation(s)
- Enmanuel J Perez
- The Miami Project to Cure Paralysis, Department of Neurosurgery, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Maria L Cepero
- The Miami Project to Cure Paralysis, Department of Neurosurgery, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Sebastian U Perez
- The Miami Project to Cure Paralysis, Department of Neurosurgery, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Joseph T Coyle
- Harvard Medical School, Department of Psychiatry, McLean Hospital, Boston, MA 02115, USA
| | - Thomas J Sick
- Department of Neurology, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Daniel J Liebl
- The Miami Project to Cure Paralysis, Department of Neurosurgery, University of Miami Miller School of Medicine, Miami, FL, USA.
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23
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Dixon KJ, Mier J, Gajavelli S, Turbic A, Bullock R, Turnley AM, Liebl DJ. EphrinB3 restricts endogenous neural stem cell migration after traumatic brain injury. Stem Cell Res 2016; 17:504-513. [PMID: 27771498 DOI: 10.1016/j.scr.2016.09.029] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/06/2016] [Revised: 08/29/2016] [Accepted: 09/24/2016] [Indexed: 10/20/2022] Open
Abstract
Traumatic brain injury (TBI) leads to a series of pathological events that can have profound influences on motor, sensory and cognitive functions. Conversely, TBI can also stimulate neural stem/progenitor cell proliferation leading to increased numbers of neuroblasts migrating outside their restrictive neurogenic zone to areas of damage in support of tissue integrity. Unfortunately, the factors that regulate migration are poorly understood. Here, we examine whether ephrinB3 functions to restrict neuroblasts from migrating outside the subventricular zone (SVZ) and rostral migratory stream (RMS). We have previously shown that ephrinB3 is expressed in tissues surrounding these regions, including the overlying corpus callosum (CC), and is reduced after controlled cortical impact (CCI) injury. Our current study takes advantage of ephrinB3 knockout mice to examine the influences of ephrinB3 on neuroblast migration into CC and cortex tissues after CCI injury. Both injury and/or ephrinB3 deficiency led to increased neuroblast numbers and enhanced migration outside the SVZ/RMS zones. Application of soluble ephrinB3-Fc molecules reduced neuroblast migration into the CC after injury and limited neuroblast chain migration in cultured SVZ explants. Our findings suggest that ephrinB3 expression in tissues surrounding neurogenic regions functions to restrict neuroblast migration outside the RMS by limiting chain migration.
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Affiliation(s)
- Kirsty J Dixon
- The Miami Project to Cure Paralysis, Department of Neurological Surgery, University of Miami, 1095 NW 14th Terrace, Miami, FL 33136, USA; Department of Physical Medicine and Rehabilitation, Virginia Commonwealth University, 1101 East Marshall Street, Richmond, VA 23298, USA.
| | - Jose Mier
- The Miami Project to Cure Paralysis, Department of Neurological Surgery, University of Miami, 1095 NW 14th Terrace, Miami, FL 33136, USA.
| | - Shyam Gajavelli
- The Miami Project to Cure Paralysis, Department of Neurological Surgery, University of Miami, 1095 NW 14th Terrace, Miami, FL 33136, USA.
| | - Alisa Turbic
- Department of Anatomy and Neuroscience, The University of Melbourne, Parkville, VIC 3010, Australia.
| | - Ross Bullock
- The Miami Project to Cure Paralysis, Department of Neurological Surgery, University of Miami, 1095 NW 14th Terrace, Miami, FL 33136, USA.
| | - Ann M Turnley
- Department of Anatomy and Neuroscience, The University of Melbourne, Parkville, VIC 3010, Australia.
| | - Daniel J Liebl
- The Miami Project to Cure Paralysis, Department of Neurological Surgery, University of Miami, 1095 NW 14th Terrace, Miami, FL 33136, USA.
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24
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Multiple faces of protein interacting with C kinase 1 (PICK1): Structure, function, and diseases. Neurochem Int 2016; 98:115-21. [DOI: 10.1016/j.neuint.2016.03.001] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Revised: 03/02/2016] [Accepted: 03/02/2016] [Indexed: 11/19/2022]
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25
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Andrade-Talavera Y, Duque-Feria P, Paulsen O, Rodríguez-Moreno A. Presynaptic Spike Timing-Dependent Long-Term Depression in the Mouse Hippocampus. Cereb Cortex 2016; 26:3637-3654. [PMID: 27282393 PMCID: PMC4961031 DOI: 10.1093/cercor/bhw172] [Citation(s) in RCA: 90] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Spike timing-dependent plasticity (STDP) is a Hebbian learning rule important for synaptic refinement during development and for learning and memory in the adult. Given the importance of the hippocampus in memory, surprisingly little is known about the mechanisms and functions of hippocampal STDP. In the present work, we investigated the requirements for induction of hippocampal spike timing-dependent long-term potentiation (t-LTP) and spike timing-dependent long-term depression (t-LTD) and the mechanisms of these 2 forms of plasticity at CA3-CA1 synapses in young (P12–P18) mouse hippocampus. We found that both t-LTP and t-LTD can be induced at hippocampal CA3-CA1 synapses by pairing presynaptic activity with single postsynaptic action potentials at low stimulation frequency (0.2 Hz). Both t-LTP and t-LTD require NMDA-type glutamate receptors for their induction, but the location and properties of these receptors are different: While t-LTP requires postsynaptic ionotropic NMDA receptor function, t-LTD does not, and whereas t-LTP is blocked by antagonists at GluN2A and GluN2B subunit-containing NMDA receptors, t-LTD is blocked by GluN2C or GluN2D subunit-preferring NMDA receptor antagonists. Both t-LTP and t-LTD require postsynaptic Ca2+ for their induction. Induction of t-LTD also requires metabotropic glutamate receptor activation, phospholipase C activation, postsynaptic IP3 receptor-mediated Ca2+ release from internal stores, postsynaptic endocannabinoid (eCB) synthesis, activation of CB1 receptors and astrocytic signaling, possibly via release of the gliotransmitter d-serine. We furthermore found that presynaptic calcineurin is required for t-LTD induction. t-LTD is expressed presynaptically as indicated by fluctuation analysis, paired-pulse ratio, and rate of use-dependent depression of postsynaptic NMDA receptor currents by MK801. The results show that CA3-CA1 synapses display both NMDA receptor-dependent t-LTP and t-LTD during development and identify a presynaptic form of hippocampal t-LTD similar to that previously described at neocortical synapses during development.
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Affiliation(s)
- Yuniesky Andrade-Talavera
- Department of Physiology, Anatomy and Cell Biology, Universidad Pablo de Olavide, ES-41013 Seville, Spain
| | - Paloma Duque-Feria
- Department of Physiology, Anatomy and Cell Biology, Universidad Pablo de Olavide, ES-41013 Seville, Spain
| | - Ole Paulsen
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge CB2 3EG, UK
| | - Antonio Rodríguez-Moreno
- Department of Physiology, Anatomy and Cell Biology, Universidad Pablo de Olavide, ES-41013 Seville, Spain
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Freyburger M, Pierre A, Paquette G, Bélanger-Nelson E, Bedont J, Gaudreault PO, Drolet G, Laforest S, Blackshaw S, Cermakian N, Doucet G, Mongrain V. EphA4 is Involved in Sleep Regulation but Not in the Electrophysiological Response to Sleep Deprivation. Sleep 2016; 39:613-24. [PMID: 26612390 DOI: 10.5665/sleep.5538] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Accepted: 10/15/2015] [Indexed: 01/10/2023] Open
Abstract
STUDY OBJECTIVES Optimal sleep is ensured by the interaction of circadian and homeostatic processes. Although synaptic plasticity seems to contribute to both processes, the specific players involved are not well understood. The EphA4 tyrosine kinase receptor is a cell adhesion protein regulating synaptic plasticity. We investigated the role of EphA4 in sleep regulation using electrocorticography in mice lacking EphA4 and gene expression measurements. METHODS EphA4 knockout (KO) mice, Clock(Δ19/Δ19) mutant mice and littermates, C57BL/6J and CD-1 mice, and Sprague-Dawley rats were studied under a 12 h light: 12 h dark cycle, under undisturbed conditions or 6 h sleep deprivation (SLD), and submitted to a 48 h electrophysiological recording and/or brain sampling at different time of day. RESULTS EphA4 KO mice showed less rapid eye movement sleep (REMS), enhanced duration of individual bouts of wakefulness and nonrapid eye movement sleep (NREMS) during the light period, and a blunted daily rhythm of NREMS sigma activity. The NREMS delta activity response to SLD was unchanged in EphA4 KO mice. However, SLD increased EphA4 expression in the thalamic/hypothalamic region in C57BL/6J mice. We further show the presence of E-boxes in the promoter region of EphA4, a lower expression of EphA4 in Clock mutant mice, a rhythmic expression of EphA4 ligands in several brain areas, expression of EphA4 in the suprachiasmatic nuclei of the hypothalamus (SCN), and finally an unchanged number of cells expressing Vip, Grp and Avp in the SCN of EphA4 KO mice. CONCLUSIONS Our results suggest that EphA4 is involved in circadian sleep regulation.
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Affiliation(s)
- Marlène Freyburger
- Center for Advanced Research in Sleep Medicine and Research Center, Hôpital du Sacré-Coeur de Montréal, Montreal, QC, Canada.,Department of Neuroscience, Université de Montréal, Montreal, QC, Canada
| | - Audrey Pierre
- Center for Advanced Research in Sleep Medicine and Research Center, Hôpital du Sacré-Coeur de Montréal, Montreal, QC, Canada
| | - Gabrielle Paquette
- Center for Advanced Research in Sleep Medicine and Research Center, Hôpital du Sacré-Coeur de Montréal, Montreal, QC, Canada
| | - Erika Bélanger-Nelson
- Center for Advanced Research in Sleep Medicine and Research Center, Hôpital du Sacré-Coeur de Montréal, Montreal, QC, Canada
| | - Joseph Bedont
- Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Pierre-Olivier Gaudreault
- Center for Advanced Research in Sleep Medicine and Research Center, Hôpital du Sacré-Coeur de Montréal, Montreal, QC, Canada.,Department of Psychology, Université de Montréal, Montreal, QC, Canada
| | - Guy Drolet
- Centre de Recherche du CHU de Québec, Université Laval, Québec, QC, Canada
| | - Sylvie Laforest
- Centre de Recherche du CHU de Québec, Université Laval, Québec, QC, Canada
| | - Seth Blackshaw
- Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Nicolas Cermakian
- Douglas Mental Health University Institute, McGill University, Montreal, QC, Canada
| | - Guy Doucet
- Department of Neuroscience, Université de Montréal, Montreal, QC, Canada
| | - Valérie Mongrain
- Center for Advanced Research in Sleep Medicine and Research Center, Hôpital du Sacré-Coeur de Montréal, Montreal, QC, Canada.,Department of Neuroscience, Université de Montréal, Montreal, QC, Canada
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Ochoa-Cortes F, Turco F, Linan-Rico A, Soghomonyan S, Whitaker E, Wehner S, Cuomo R, Christofi FL. Enteric Glial Cells: A New Frontier in Neurogastroenterology and Clinical Target for Inflammatory Bowel Diseases. Inflamm Bowel Dis 2016; 22:433-49. [PMID: 26689598 PMCID: PMC4718179 DOI: 10.1097/mib.0000000000000667] [Citation(s) in RCA: 116] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Accepted: 08/29/2015] [Indexed: 12/12/2022]
Abstract
The word "glia" is derived from the Greek word "γλoια," glue of the enteric nervous system, and for many years, enteric glial cells (EGCs) were believed to provide mainly structural support. However, EGCs as astrocytes in the central nervous system may serve a much more vital and active role in the enteric nervous system, and in homeostatic regulation of gastrointestinal functions. The emphasis of this review will be on emerging concepts supported by basic, translational, and/or clinical studies, implicating EGCs in neuron-to-glial (neuroglial) communication, motility, interactions with other cells in the gut microenvironment, infection, and inflammatory bowel diseases. The concept of the "reactive glial phenotype" is explored as it relates to inflammatory bowel diseases, bacterial and viral infections, postoperative ileus, functional gastrointestinal disorders, and motility disorders. The main theme of this review is that EGCs are emerging as a new frontier in neurogastroenterology and a potential therapeutic target. New technological innovations in neuroimaging techniques are facilitating progress in the field, and an update is provided on exciting new translational studies. Gaps in our knowledge are discussed for further research. Restoring normal EGC function may prove to be an efficient strategy to dampen inflammation. Probiotics, palmitoylethanolamide (peroxisome proliferator-activated receptor-α), interleukin-1 antagonists (anakinra), and interventions acting on nitric oxide, receptor for advanced glycation end products, S100B, or purinergic signaling pathways are relevant clinical targets on EGCs with therapeutic potential.
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Affiliation(s)
| | - Fabio Turco
- Department of Anesthesiology, The Ohio State University, Columbus, Ohio
- Department of Clinical and Experimental Medicine, Gastroenterological Unit, “Federico II” University of Naples, Naples, Italy; and
| | | | - Suren Soghomonyan
- Department of Anesthesiology, The Ohio State University, Columbus, Ohio
| | - Emmett Whitaker
- Department of Anesthesiology, The Ohio State University, Columbus, Ohio
| | - Sven Wehner
- Department of Surgery, University of Bonn, Bonn, Germany
| | - Rosario Cuomo
- Department of Clinical and Experimental Medicine, Gastroenterological Unit, “Federico II” University of Naples, Naples, Italy; and
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Kiriyama Y, Nochi H. D-Amino Acids in the Nervous and Endocrine Systems. SCIENTIFICA 2016; 2016:6494621. [PMID: 28053803 PMCID: PMC5178360 DOI: 10.1155/2016/6494621] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2016] [Accepted: 11/14/2016] [Indexed: 05/12/2023]
Abstract
Amino acids are important components for peptides and proteins and act as signal transmitters. Only L-amino acids have been considered necessary in mammals, including humans. However, diverse D-amino acids, such as D-serine, D-aspartate, D-alanine, and D-cysteine, are found in mammals. Physiological roles of these D-amino acids not only in the nervous system but also in the endocrine system are being gradually revealed. N-Methyl-D-aspartate (NMDA) receptors are associated with learning and memory. D-Serine, D-aspartate, and D-alanine can all bind to NMDA receptors. H2S generated from D-cysteine reduces disulfide bonds in receptors and potentiates their activity. Aberrant receptor activity is related to diseases of the central nervous system (CNS), such as Alzheimer's disease, amyotrophic lateral sclerosis, and schizophrenia. Furthermore, D-amino acids are detected in parts of the endocrine system, such as the pineal gland, hypothalamus, pituitary gland, pancreas, adrenal gland, and testis. D-Aspartate is being investigated for the regulation of hormone release from various endocrine organs. Here we focused on recent findings regarding the synthesis and physiological functions of D-amino acids in the nervous and endocrine systems.
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Affiliation(s)
- Yoshimitsu Kiriyama
- Kagawa School of Pharmaceutical Sciences, Tokushima Bunri University, Shido 1314-1, Sanuki, Kagawa 769-2193, Japan
| | - Hiromi Nochi
- Kagawa School of Pharmaceutical Sciences, Tokushima Bunri University, Shido 1314-1, Sanuki, Kagawa 769-2193, Japan
- *Hiromi Nochi:
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29
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Dines M, Lamprecht R. The Role of Ephs and Ephrins in Memory Formation. Int J Neuropsychopharmacol 2015; 19:pyv106. [PMID: 26371183 PMCID: PMC4851260 DOI: 10.1093/ijnp/pyv106] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/06/2015] [Accepted: 09/10/2015] [Indexed: 12/22/2022] Open
Abstract
The ability to efficiently store memories in the brain is a fundamental process and its impairment is associated with multiple human mental disorders. Evidence indicates that long-term memory formation involves alterations of synaptic efficacy produced by modifications in neural transmission and morphology. The Eph receptors and their cognate ephrin ligands have been shown to be involved in these key neuronal processes by regulating events such as presynaptic transmitter release, postsynaptic glutamate receptor conductance and trafficking, synaptic glutamate reuptake, and dendritic spine morphogenesis. Recent findings show that Ephs and ephrins are needed for memory formation in different organisms. These proteins participate in the formation of various types of memories that are subserved by different neurons and brain regions. Ephs and ephrins are involved in brain disorders and diseases with memory impairment symptoms, including Alzheimer's disease and anxiety. Drugs that agonize or antagonize Ephs/ephrins signaling have been developed and could serve as therapeutic agents to treat such diseases. Ephs and ephrins may therefore induce cellular alterations mandatory for memory formation and serve as a target for pharmacological intervention for treatment of memory-related brain diseases.
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Affiliation(s)
| | - Raphael Lamprecht
- Sagol Department of Neurobiology, Faculty of Natural Sciences, University of Haifa, Israel.
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30
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Carbonic anhydrase-8 regulates inflammatory pain by inhibiting the ITPR1-cytosolic free calcium pathway. PLoS One 2015; 10:e0118273. [PMID: 25734498 PMCID: PMC4347988 DOI: 10.1371/journal.pone.0118273] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2014] [Accepted: 01/12/2015] [Indexed: 01/01/2023] Open
Abstract
Calcium dysregulation is causally linked with various forms of neuropathology including seizure disorders, multiple sclerosis, Huntington’s disease, Alzheimer’s, spinal cerebellar ataxia (SCA) and chronic pain. Carbonic anhydrase-8 (Car8) is an allosteric inhibitor of inositol trisphosphate receptor-1 (ITPR1), which regulates intracellular calcium release fundamental to critical cellular functions including neuronal excitability, neurite outgrowth, neurotransmitter release, mitochondrial energy production and cell fate. In this report we test the hypothesis that Car8 regulation of ITPR1 and cytoplasmic free calcium release is critical to nociception and pain behaviors. We show Car8 null mutant mice (MT) exhibit mechanical allodynia and thermal hyperalgesia. Dorsal root ganglia (DRG) from MT also demonstrate increased steady-state ITPR1 phosphorylation (pITPR1) and cytoplasmic free calcium release. Overexpression of Car8 wildtype protein in MT nociceptors complements Car8 deficiency, down regulates pITPR1 and abolishes thermal and mechanical hypersensitivity. We also show that Car8 nociceptor overexpression alleviates chronic inflammatory pain. Finally, inflammation results in downregulation of DRG Car8 that is associated with increased pITPR1 expression relative to ITPR1, suggesting a possible mechanism of acute hypersensitivity. Our findings indicate Car8 regulates the ITPR1-cytosolic free calcium pathway that is critical to nociception, inflammatory pain and possibly other neuropathological states. Car8 and ITPR1 represent new therapeutic targets for chronic pain.
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Coelho-Aguiar JDM, Bon-Frauches AC, Gomes ALT, Veríssimo CP, Aguiar DP, Matias D, Thomasi BBDM, Gomes AS, Brito GADC, Moura-Neto V. The enteric glia: identity and functions. Glia 2015; 63:921-35. [PMID: 25703790 DOI: 10.1002/glia.22795] [Citation(s) in RCA: 74] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2014] [Accepted: 01/07/2015] [Indexed: 01/04/2023]
Abstract
Enteric glial cells were first described at the end of the 19th century, but they attracted more interest from researchers only in the last decades of the 20th. Although, they have a different embryological origin, the enteric GLIA share many characteristics with astrocytes, the main glial cell type of the central nervous system (CNS), such as in their expression of the same markers and in their functions. Here we review the construction of the enteric nervous system (ENS), with a focus on enteric glia, and also the main studies that have revealed the action of enteric glia in different aspects of gastrointestinal tract homeostasis, such as in the intestinal barrier, in communications with neurons, and in their action as progenitor cells. We also discuss recent discoveries about the roles of enteric glia in different disorders that affect the ENS, such as degenerative pathologies including Parkinson's and prion diseases, and in cases of intestinal diseases and injury.
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Affiliation(s)
- Juliana de Mattos Coelho-Aguiar
- Instituto Estadual do Cérebro Paulo Niemeyer, Secretaria de Estado de Saúde do Rio de Janeiro - SES/RJ, Rio de Janeiro, Brazil; Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
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Crunelli V, Carmignoto G, Steinhäuser C. Novel astrocyte targets: new avenues for the therapeutic treatment of epilepsy. Neuroscientist 2015; 21:62-83. [PMID: 24609207 PMCID: PMC4361461 DOI: 10.1177/1073858414523320] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
During the last 20 years, it has been well established that a finely tuned, continuous crosstalk between neurons and astrocytes not only critically modulates physiological brain functions but also underlies many neurological diseases. In particular, this novel way of interpreting brain activity is markedly influencing our current knowledge of epilepsy, prompting a re-evaluation of old findings and guiding novel experimentation. Here, we review recent studies that have unraveled novel and unique contributions of astrocytes to the generation and spread of convulsive and nonconvulsive seizures and epileptiform activity. The emerging scenario advocates an overall framework in which a dynamic and reciprocal interplay among astrocytic and neuronal ensembles is fundamental for a fuller understanding of epilepsy. In turn, this offers novel astrocytic targets for the development of those really novel chemical entities for the control of convulsive and nonconvulsive seizures that have been acknowledged as a key priority in the management of epilepsy.
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Affiliation(s)
- Vincenzo Crunelli
- Neuroscience Division, School of Biosciences, Cardiff University, Cardiff, UK
| | - Giorgio Carmignoto
- Centro Nazionale della Ricerca, Neuroscience Institute and Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Christian Steinhäuser
- Institute of Cellular Neurosciences, Medical Faculty, University of Bonn, Bonn, Germany
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Welcome MO, Mastorakis NE, Pereverzev VA. Sweet taste receptor signaling network: possible implication for cognitive functioning. Neurol Res Int 2015; 2015:606479. [PMID: 25653876 PMCID: PMC4306214 DOI: 10.1155/2015/606479] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Accepted: 12/20/2014] [Indexed: 01/01/2023] Open
Abstract
Sweet taste receptors are transmembrane protein network specialized in the transmission of information from special "sweet" molecules into the intracellular domain. These receptors can sense the taste of a range of molecules and transmit the information downstream to several acceptors, modulate cell specific functions and metabolism, and mediate cell-to-cell coupling through paracrine mechanism. Recent reports indicate that sweet taste receptors are widely distributed in the body and serves specific function relative to their localization. Due to their pleiotropic signaling properties and multisubstrate ligand affinity, sweet taste receptors are able to cooperatively bind multiple substances and mediate signaling by other receptors. Based on increasing evidence about the role of these receptors in the initiation and control of absorption and metabolism, and the pivotal role of metabolic (glucose) regulation in the central nervous system functioning, we propose a possible implication of sweet taste receptor signaling in modulating cognitive functioning.
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Affiliation(s)
- Menizibeya O. Welcome
- World Scientific and Engineering Academy and Society, Ag. Ioannou Theologou 17-23, Zografou, 15773 Athens, Greece
| | - Nikos E. Mastorakis
- World Scientific and Engineering Academy and Society, Ag. Ioannou Theologou 17-23, Zografou, 15773 Athens, Greece
- Department of Industrial Engineering, Technical University of Sofia, 8 Kl. Ohridski Boulevard, 1000 Sofia, Bulgaria
| | - Vladimir A. Pereverzev
- Department of Normal Physiology, Belarusian State Medical University, Dzerzhinsky Avenue 83, 220116 Minsk, Belarus
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Marchetti M, Bruno S, Campanini B, Bettati S, Peracchi A, Mozzarelli A. Regulation of human serine racemase activity and dynamics by halides, ATP and malonate. Amino Acids 2014; 47:163-73. [PMID: 25331425 DOI: 10.1007/s00726-014-1856-2] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2014] [Accepted: 10/09/2014] [Indexed: 02/03/2023]
Abstract
D-Serine is a non-proteinogenic amino acid that acts as a co-agonist of the NMDA receptors in the central nervous system. D-Serine is produced by human serine racemase (hSR), a homodimeric pyridoxal 5'-phosphate (PLP)-dependent enzyme that also catalyzes the physiologically relevant β-elimination of both L- and D-serine to pyruvate and ammonia. After improving the protein purification yield and stability, which had so far limited the biochemical characterization of hSR, we found that the catalytic activity is affected by halides, in the order fluoride > chloride > bromide. On the contrary, iodide elicited a complete inhibition, accompanied by a modulation of the tautomeric equilibrium of the internal aldimine. We also investigated the reciprocal effects of ATP and malonate, an inhibitor that reversibly binds at the active site, 20 Å away from the ATP-binding site. ATP increased ninefold the affinity of hSR for malonate and malonate increased 100-fold that of ATP, confirming an allosteric interaction between the two binding sites. To further investigate this allosteric communication, we probed the active site accessibility by quenching of the coenzyme fluorescence in the absence and presence of ATP. We found that ATP stabilizes a closed conformation of the external aldimine Schiff base, suggesting a possible mechanism for ATP-induced hSR activation.
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Ephrin/Ephrin receptor expression in ammonia-treated rat astrocytes and in human cerebral cortex in hepatic encephalopathy. Neurochem Res 2014; 40:274-83. [PMID: 25064044 DOI: 10.1007/s11064-014-1389-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2014] [Revised: 07/11/2014] [Accepted: 07/15/2014] [Indexed: 12/31/2022]
Abstract
Hepatic encephalopathy (HE) represents a neuropsychiatric syndrome, which evolves as a consequence of a low grade cerebral edema and a concomitant oxidative/nitrosative stress response. Ephrin receptors (EphR) and their ligands (ephrins) regulate astrocytic glutamate uptake and gliotransmitter release thereby governing neurotransmission, but their role in HE and ammonia toxicity is unclear. We therefore tested effects of ammonia on expression levels of EphR/ephrin isoforms in cultured rat astrocytes and analysed underlying mechanisms. NH4Cl induced mRNA expression changes of several EphR/ephrin isoforms in a methionine sulfoximine-, NADPH oxidase- and NO synthase-dependent manner in cultured astrocytes. A prominent upregulation was noted for EphR A4 mRNA and protein in NH4Cl-treated astrocytes. NH4Cl-treatment decreased EphR A4 molecular mass to similar extent as found in astrocytes treated with the N-glycosylation inhibitor tunicamycin. Knockdown of EphR A4 by siRNA, or treating astrocytes with NH4Cl or tunicamycin abolished fibroblast growth factor-induced and EphR A4-dependent astrocyte proliferation. NH4Cl-treatment also decreased GLAST mRNA levels in cultured astrocytes. This effect was sensitive to inhibitors of NAPDH oxidase or glutamine synthetase, but was insensitive to siRNA-mediated EphR A4 knockdown. Eph/ephrin gene expression changes were also found in post mortem brain samples of cirrhotic patients without or with HE compared to controls suggesting a potential in vivo relevance of the present findings. The present study suggests that ammonia modulates EphR/ephrin signaling in astrocytes and in the brain of cirrhotic patients with HE with potential implications for deranged neurotransmission in HE.
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Behavioral improvement and regulation of molecules related to neuroplasticity in ischemic rat spinal cord treated with PEDF. Neural Plast 2014; 2014:451639. [PMID: 25110592 PMCID: PMC4106224 DOI: 10.1155/2014/451639] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2013] [Revised: 06/04/2014] [Accepted: 06/05/2014] [Indexed: 11/28/2022] Open
Abstract
Pigment epithelium derived factor (PEDF) exerts trophic actions to motoneurons and modulates nonneuronal restorative events, but its effects on neuroplasticity responses after spinal cord (SC) injury are unknown. Rats received a low thoracic SC photothrombotic ischemia and local injection of PEDF and were evaluated behaviorally six weeks later. PEDF actions were detailed in SC ventral horn (motor) in the levels of the lumbar central pattern generator (CPG), far from the injury site. Molecules related to neuroplasticity (MAP-2), those that are able to modulate such event, for instance, neurotrophic factors (NT-3, GDNF, BDNF, and FGF-2), chondroitin sulfate proteoglycans (CSPG), and those associated with angiogenesis and antiapoptosis (laminin and Bcl-2) and Eph (receptor)/ephrin system were evaluated at cellular or molecular levels. PEDF injection improved motor behavioral performance and increased MAP-2 levels and dendritic processes in the region of lumbar CPG. Treatment also elevated GDNF and decreased NT-3, laminin, and CSPG. Injury elevated EphA4 and ephrin-B1 levels, and PEDF treatment increased ephrin A2 and ephrins B1, B2, and B3. Eph receptors and ephrins were found in specific populations of neurons and astrocytes. PEDF treatment to SC injury triggered neuroplasticity in lumbar CPG and regulation of neurotrophic factors, extracellular matrix molecules, and ephrins.
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Martineau M, Parpura V, Mothet JP. Cell-type specific mechanisms of D-serine uptake and release in the brain. Front Synaptic Neurosci 2014; 6:12. [PMID: 24910611 PMCID: PMC4039169 DOI: 10.3389/fnsyn.2014.00012] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2014] [Accepted: 05/02/2014] [Indexed: 12/30/2022] Open
Abstract
Accumulating evidence during the last decade established that D-serine is a key signaling molecule utilized by neurons and astroglia in the mammalian central nervous system. D-serine is increasingly appreciated as the main physiological endogenous coagonist for synaptic NMDA receptors at central excitatory synapses; it is mandatory for long-term changes in synaptic strength, memory, learning, and social interactions. Alterations in the extracellular levels of D-serine leading to disrupted cell-cell signaling are a trademark of many chronic or acute neurological (i.e., Alzheimer disease, epilepsy, stroke) and psychiatric (i.e., schizophrenia) disorders, and are associated with addictive behavior (i.e., cocaine addiction). Indeed, fine tuning of the extracellular levels of D-serine, achieved by various molecular machineries and signaling pathways, is necessary for maintenance of accurate NMDA receptor functions. Here, we review the experimental data supporting the notion that astroglia and neurons use different pathways to regulate levels of extracellular D-serine.
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Affiliation(s)
- Magalie Martineau
- Department of Cellular Biophysics, Institute for Medical Physics and Biophysics, University of Muenster Muenster, Germany
| | - Vladimir Parpura
- Department of Neurobiology, University of Alabama at Birmingham Birmingham, AL, USA ; Department of Biotechnology, University of Rijeka Rijeka, Croatia
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Theus MH, Ricard J, Glass SJ, Travieso LG, Liebl DJ. EphrinB3 blocks EphB3 dependence receptor functions to prevent cell death following traumatic brain injury. Cell Death Dis 2014; 5:e1207. [PMID: 24810043 PMCID: PMC4047907 DOI: 10.1038/cddis.2014.165] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2013] [Revised: 02/28/2014] [Accepted: 03/17/2014] [Indexed: 01/22/2023]
Abstract
Eph receptor tyrosine kinases and their membrane-bound ligands, ephrins, have a variety of roles in the developing and adult central nervous system that require direct cell-cell interactions; including regulating axon path finding, cell proliferation, migration and synaptic plasticity. Recently, we identified a novel pro-survival role for ephrins in the adult subventricular zone, where ephrinB3 blocks Eph-mediated cell death during adult neurogenesis. Here, we examined whether EphB3 mediates cell death in the adult forebrain following traumatic brain injury and whether ephrinB3 infusion could limit this effect. We show that EphB3 co-labels with microtubule-associated protein 2-positive neurons in the adult cortex and is closely associated with ephrinB3 ligand, which is reduced following controlled cortical impact (CCI) injury. In the complete absence of EphB3 (EphB3(-/-)), we observed reduced terminal deoxynucleotidyl transferase-dUTP nick end labeling (TUNEL), and functional improvements in motor deficits after CCI injury as compared with wild-type and ephrinB3(-/-) mice. We also demonstrated that EphB3 exhibits dependence receptor characteristics as it is cleaved by caspases and induces cell death, which is not observed in the presence of ephrinB3. Following trauma, infusion of pre-clustered ephrinB3-Fc molecules (eB3-Fc) into the contralateral ventricle reduced cortical infarct volume and TUNEL staining in the cortex, dentate gyrus and CA3 hippocampus of wild-type and ephrinB3(-/-) mice, but not EphB3(-/-) mice. Similarly, application of eB3-Fc improved motor functions after CCI injury. We conclude that EphB3 mediates cell death in the adult cortex through a novel dependence receptor-mediated cell death mechanism in the injured adult cortex and is attenuated following ephrinB3 stimulation.
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Affiliation(s)
- M H Theus
- Department of Biomedical Sciences and Pathobiology, Virginia-Maryland Regional College of Veterinary Medicine, 215 Duck Pond Drive, Blacksburg, VA 24061, USA
| | - J Ricard
- Miami Project to Cure Paralysis, Department of Neurological Surgery, University of Miami Miller School of Medicine, 1095 NW 14th Terrace, R-48, Miami, FL 33136, USA
| | - S J Glass
- Miami Project to Cure Paralysis, Department of Neurological Surgery, University of Miami Miller School of Medicine, 1095 NW 14th Terrace, R-48, Miami, FL 33136, USA
| | - L G Travieso
- Miami Project to Cure Paralysis, Department of Neurological Surgery, University of Miami Miller School of Medicine, 1095 NW 14th Terrace, R-48, Miami, FL 33136, USA
| | - D J Liebl
- Miami Project to Cure Paralysis, Department of Neurological Surgery, University of Miami Miller School of Medicine, 1095 NW 14th Terrace, R-48, Miami, FL 33136, USA
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Araque A, Carmignoto G, Haydon PG, Oliet SHR, Robitaille R, Volterra A. Gliotransmitters travel in time and space. Neuron 2014; 81:728-39. [PMID: 24559669 DOI: 10.1016/j.neuron.2014.02.007] [Citation(s) in RCA: 837] [Impact Index Per Article: 83.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/03/2014] [Indexed: 12/12/2022]
Abstract
The identification of the presence of active signaling between astrocytes and neurons in a process termed gliotransmission has caused a paradigm shift in our thinking about brain function. However, we are still in the early days of the conceptualization of how astrocytes influence synapses, neurons, networks, and ultimately behavior. In this Perspective, our goal is to identify emerging principles governing gliotransmission and consider the specific properties of this process that endow the astrocyte with unique functions in brain signal integration. We develop and present hypotheses aimed at reconciling confounding reports and define open questions to provide a conceptual framework for future studies. We propose that astrocytes mainly signal through high-affinity slowly desensitizing receptors to modulate neurons and perform integration in spatiotemporal domains complementary to those of neurons.
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Affiliation(s)
- Alfonso Araque
- Instituto Cajal, Consejo Superior de Investigaciones Científicas, 28002 Madrid, Spain; Department of Neuroscience, University of Minnesota, Minneapolis, MN 55455, USA
| | - Giorgio Carmignoto
- Istituto di Neuroscienze, Consiglio Nazionale delle Ricerche and Dipartimento Scienze Biomediche, Università di Padova, 35121 Padova, Italy.
| | - Philip G Haydon
- Department of Neuroscience, Tufts University School of Medicine, Boston, MA 02111, USA
| | - Stéphane H R Oliet
- Inserm U862, Neurocentre Magendie, 33077 Bordeaux, France; Université de Bordeaux, 33077 Bordeaux, France
| | - Richard Robitaille
- Département de Neurosciences, Université de Montréal, Montréal, QC H3C 3J7, Canada; Groupe de Recherche sur le Système Nerveux Central, Université de Montréal, Montréal, QC H3C 3J7, Canada
| | - Andrea Volterra
- Département de Neurosciences Fondamentales (DNF), Faculté de Biologie et de Médecine, Université de Lausanne, 1005 Lausanne, Switzerland
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Okuda H, Tatsumi K, Morita S, Shibukawa Y, Korekane H, Horii-Hayashi N, Wada Y, Taniguchi N, Wanaka A. Chondroitin sulfate proteoglycan tenascin-R regulates glutamate uptake by adult brain astrocytes. J Biol Chem 2013; 289:2620-31. [PMID: 24337573 DOI: 10.1074/jbc.m113.504787] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
In our previous study, the CS-56 antibody, which recognizes a chondroitin sulfate moiety, labeled a subset of adult brain astrocytes, yielding a patchy extracellular matrix pattern. To explore the molecular nature of CS-56-labeled glycoproteins, we purified glycoproteins of the adult mouse cerebral cortex using a combination of anion-exchange, charge-transfer, and size-exclusion chromatographies. One of the purified proteins was identified as tenascin-R (TNR) by mass spectrometric analysis. When we compared TNR mRNA expression patterns with the distribution patterns of CS-56-positive cells, TNR mRNA was detected in CS-56-positive astrocytes. To examine the functions of TNR in astrocytes, we first confirmed that cultured astrocytes also expressed TNR protein. TNR knockdown by siRNA expression significantly reduced glutamate uptake in cultured astrocytes. Furthermore, expression of mRNA and protein of excitatory amino acid transporter 1 (GLAST), which is a major component of astrocytic glutamate transporters, was reduced by TNR knockdown. Our results suggest that TNR is expressed in a subset of astrocytes and contributes to glutamate homeostasis by regulating astrocytic GLAST expression.
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Affiliation(s)
- Hiroaki Okuda
- From the Departments of Anatomy and Neuroscience and
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41
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The role of astrocytes in the regulation of synaptic plasticity and memory formation. Neural Plast 2013; 2013:185463. [PMID: 24369508 PMCID: PMC3867861 DOI: 10.1155/2013/185463] [Citation(s) in RCA: 111] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2013] [Revised: 10/07/2013] [Accepted: 11/05/2013] [Indexed: 12/22/2022] Open
Abstract
Astrocytes regulate synaptic transmission and play a role in the formation of new memories, long-term potentiation (LTP), and functional synaptic plasticity. Specifically, astroglial release of glutamate, ATP, and cytokines likely alters the survivability and functioning of newly formed connections. Among these pathways, regulation of glutamate appears to be most directly related to the promotion of LTP, which is highly dependent on the synchronization of synaptic receptors through the regulation of excitatory postsynaptic potentials. Moreover, regulation of postsynaptic glutamate receptors, particularly AMPA receptors, is dependent on signaling by ATP synthesized in astrocytes. Finally, cytokine signaling is also implicated in regulating LTP, but is likely most important in plasticity following tissue damage. Despite the role of these signaling factors in regulating LTP and functional plasticity, an integrative model of these factors has not yet been elucidated. In this review, we seek to summarize the current body of evidence on astrocytic mechanisms for regulation of LTP and functional plasticity, and provide an integrative model of the processes.
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42
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Abstract
The modulation of synaptic plasticity by NMDA receptor (NMDAR)-mediated processes is essential for many forms of learning and memory. Activation of NMDARs by glutamate requires the binding of a coagonist to a regulatory site of the receptor. In many forebrain regions, this coagonist is d-serine. Here, we show that experimental epilepsy in rats is associated with a reduction in the CNS levels of d-serine, which leads to a desaturation of the coagonist binding site of synaptic and extrasynaptic NMDARs. In addition, the subunit composition of synaptic NMDARs changes in chronic epilepsy. The desaturation of NMDARs causes a deficit in hippocampal long-term potentiation, which can be rescued with exogenously supplied d-serine. Importantly, exogenous d-serine improves spatial learning in epileptic animals. These results strongly suggest that d-serine deficiency is important in the amnestic symptoms of temporal lobe epilepsy. Our results point to a possible clinical utility of d-serine to alleviate these disease manifestations.
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Gustafson EC, Morgans CW, Tekmen M, Sullivan SJ, Esguerra M, Konno R, Miller RF. Retinal NMDA receptor function and expression are altered in a mouse lacking D-amino acid oxidase. J Neurophysiol 2013; 110:2718-26. [PMID: 24068757 DOI: 10.1152/jn.00310.2013] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
D-serine is present in the vertebrate retina and serves as a coagonist for the N-methyl-D-aspartate (NMDA) receptors of ganglion cells. Although the enzyme D-amino acid oxidase (DAO) has been implicated as a pathway for d-serine degradation, its role in the retina has not been established. In this study, we investigated the role of DAO in regulating D-serine levels using a mutant mouse line deficient in DAO (ddY/DAO(-)) and compared these results with their wild-type counterparts (ddY/DAO(+)). Our results show that DAO is functionally present in the mouse retina and normally serves to reduce the background levels of D-serine. The enzymatic activity of DAO was restricted to the inner plexiform layer as determined by histochemical analysis. Using capillary electrophoresis, we showed that mutant mice had much higher levels of D-serine. Whole cell recordings from identified retinal ganglion cells demonstrated that DAO-deficient animals had light-evoked synaptic activity strongly biased toward a high NMDA-to-AMPA receptor ratio. In contrast, recordings from wild-type ganglion cells showed a more balanced ratio between the two receptor subclasses. Immunostaining for AMPA and NMDA receptors was carried out to compare the two receptor ratios by quantitative immunofluorescence. These studies revealed that the mutant mouse had a significantly higher representation of NMDA receptors compared with the wild-type controls. We conclude that 1) DAO is an important regulatory enzyme and normally functions to reduce D-serine levels in the retina, and 2) D-serine levels play a role in the expression of NMDA receptors and the NMDA-to-AMPA receptor ratio.
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Affiliation(s)
- Eric C Gustafson
- Department of Neuroscience, University of Minnesota, Minneapolis, Minnesota
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Focant MC, Goursaud S, Boucherie C, Dumont AO, Hermans E. PICK1 expression in reactive astrocytes within the spinal cord of amyotrophic lateral sclerosis (ALS) rats. Neuropathol Appl Neurobiol 2013; 39:231-42. [PMID: 22624977 DOI: 10.1111/j.1365-2990.2012.01282.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
AIMS The protein interacting with C kinase 1 (PICK1), a PDZ domain-containing protein mainly expressed in the central nervous system, interacts with the glutamate receptor subunit GluR2, with the glutamate transporter GLT-1b and with the enzyme serine racemase. These three proteins appear as key actors in the glutamate-mediated excitotoxicity associated with amyotrophic lateral sclerosis (ALS), in both patients and animal models of the disease. In this study, we examined the expression of PICK1 in the spinal cord of transgenic rats expressing a mutated form of the human superoxide dismutase 1 (hSOD1(G93A) ) during the progression of the disease. METHODS Expression of PICK1 was examined by real-time qPCR at presymptomatic and symptomatic stages as well as at end-stage. The expression of PICK1 in the different cell types of the spinal cord was examined by immunohistochemistry. RESULTS The overall expression of PICK1 is not modified in cervical and lumbar spinal cord of transgenic (hSOD1(G93A) ) rats during the progression of the disease. Nonetheless, immunohistochemical studies of lumbar ventral horns revealed a shift of PICK1 expression from motor neurones in healthy rats to activated astrocytes in end-stage hSOD1(G93A) animals. CONCLUSIONS Considering the documented influence of PICK1 expression on d-serine release and glutamate transport in astrocytes, these findings point to a potential implication of PICK1 in the progression of ALS.
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Affiliation(s)
- M C Focant
- Group of Neuropharmacology, Institute of Neuroscience, Université catholique de Louvain, Brussels, Belgium
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Repetitive hyperbaric oxygen treatment attenuates complete Freund's adjuvant-induced pain and reduces glia-mediated neuroinflammation in the spinal cord. THE JOURNAL OF PAIN 2013; 14:747-58. [PMID: 23680474 DOI: 10.1016/j.jpain.2013.02.003] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2012] [Revised: 01/14/2013] [Accepted: 02/05/2013] [Indexed: 12/23/2022]
Abstract
UNLABELLED Hyperbaric oxygen (HBO) therapy is reported to attenuate pain in both clinical pain conditions and animal pain models, but the underlying mechanism remains to be investigated. Here, we show that 7 daily 60-minute HBO (100% oxygen, 2 atmosphere absolute) treatments effectively and persistently inhibited heat hyperalgesia, mechanical allodynia, and paw edema induced by peripheral injection of complete Freund's adjuvant (CFA). Five daily 60-minute HBO treatments also produced a prolonged reversal effect of the ongoing inflammatory pain. Furthermore, such an HBO treatment reduced CFA-induced activation of glial cells, phosphorylation of mitogen-activated protein kinases, and production of a variety of proinflammatory cytokines (tumor necrosis factor alpha [TNF-α], interleukin-1 beta [IL-1β], and interleukin-6 [IL-6]) and chemokines (monocyte chemoattractant protein-1 [MCP-1], keratinocyte-derived chemokine [KC], and IFN-gamma-inducible protein 10 [IP-10]) in the spinal cord. HBO treatment also decreased lipopolysaccharide-induced mRNA expression of these cytokines and chemokines in primary cultures of astrocytes and microglia. In addition, the mRNA expressions of IL-1β, IL-6, MCP-1, KC, and IP-10 in the inflamed paw skin were decreased by HBO. Taken together, these data suggest that HBO treatment is an effective therapy for inflammatory pain in animals. The inhibition of the neuroinflammation that is mediated by glial cells and inflammatory mediators may, at least in part, contribute to the antinociceptive effect of HBO therapy. PERSPECTIVE Our results suggest that repetitive HBO treatment attenuates CFA-induced pain and reduces glial activation and inflammatory mediators' production. These findings provide evidence of the antinociception effect of HBO on inflammatory pain and characterize some of the underlying mechanisms.
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Van Horn MR, Sild M, Ruthazer ES. D-serine as a gliotransmitter and its roles in brain development and disease. Front Cell Neurosci 2013; 7:39. [PMID: 23630460 PMCID: PMC3632749 DOI: 10.3389/fncel.2013.00039] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2013] [Accepted: 03/26/2013] [Indexed: 01/05/2023] Open
Abstract
The development of new techniques to study glial cells has revealed that they are active participants in the development of functional neuronal circuits. Calcium imaging studies demonstrate that glial cells actively sense and respond to neuronal activity. Glial cells can produce and release neurotransmitter-like molecules, referred to as gliotransmitters, that can in turn influence the activity of neurons and other glia. One putative gliotransmitter, D-serine is believed to be an endogenous co-agonist for synaptic N-methyl-D-aspartate receptors (NMDARs), modulating synaptic transmission and plasticity mediated by this receptor. The observation that D-serine levels in the mammalian brain increase during early development, suggests a possible role for this gliotransmitter in normal brain development and circuit refinement. In this review we will examine the data that D-serine and its associated enzyme serine racemase are developmentally regulated. We will consider the evidence that D-serine is actively released by glial cells and examine the studies that have implicated D-serine as a critical player involved in regulating NMDAR-mediated synaptic transmission and neuronal migration during development. Furthermore, we will consider how dysregulation of D-serine may play an important role in the etiology of neurological and psychiatric diseases.
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Affiliation(s)
- Marion R Van Horn
- Montreal Neurological Institute, McGill University Montreal, QC, Canada
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47
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Focant MC, Hermans E. Protein interacting with C kinase and neurological disorders. Synapse 2013; 67:532-40. [DOI: 10.1002/syn.21657] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2012] [Accepted: 02/16/2013] [Indexed: 01/15/2023]
Affiliation(s)
- Marylène C. Focant
- Institute of Neuroscience, Université catholique de Louvain; Brussels; Belgium
| | - Emmanuel Hermans
- Institute of Neuroscience, Université catholique de Louvain; Brussels; Belgium
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48
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Astrocyte-induced cortical vasodilation is mediated by D-serine and endothelial nitric oxide synthase. Proc Natl Acad Sci U S A 2013; 110:3149-54. [PMID: 23386721 DOI: 10.1073/pnas.1215929110] [Citation(s) in RCA: 81] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Astrocytes play a critical role in neurovascular coupling by providing a physical linkage from synapses to arterioles and releasing vaso-active gliotransmitters. We identified a gliotransmitter pathway by which astrocytes influence arteriole lumen diameter. Astrocytes synthesize and release NMDA receptor coagonist, D-serine, in response to neurotransmitter input. Mouse cortical slice astrocyte activation by metabotropic glutamate receptors or photolysis of caged Ca(2+) produced dilation of penetrating arterioles in a manner attenuated by scavenging D-serine with D-amino acid oxidase, deleting the enzyme responsible for D-serine synthesis (serine racemase) or blocking NMDA receptor glycine coagonist sites with 5,7-dichlorokynurenic acid. We also found that dilatory responses were dramatically reduced by inhibition or elimination of endothelial nitric oxide synthase and that the vasodilatory effect of endothelial nitric oxide synthase is likely mediated by suppressing levels of the vasoconstrictor arachidonic acid metabolite, 20-hydroxy arachidonic acid. Our results provide evidence that D-serine coactivation of NMDA receptors and endothelial nitric oxide synthase is involved in astrocyte-mediated neurovascular coupling.
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Diniz LP, Almeida JC, Tortelli V, Vargas Lopes C, Setti-Perdigão P, Stipursky J, Kahn SA, Romão LF, de Miranda J, Alves-Leon SV, de Souza JM, Castro NG, Panizzutti R, Gomes FCA. Astrocyte-induced synaptogenesis is mediated by transforming growth factor β signaling through modulation of D-serine levels in cerebral cortex neurons. J Biol Chem 2012; 287:41432-45. [PMID: 23055518 PMCID: PMC3510841 DOI: 10.1074/jbc.m112.380824] [Citation(s) in RCA: 166] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Assembly of synapses requires proper coordination between pre- and postsynaptic elements. Identification of cellular and molecular events in synapse formation and maintenance is a key step to understand human perception, learning, memory, and cognition. A key role for astrocytes in synapse formation and function has been proposed. Here, we show that transforming growth factor β (TGF-β) signaling is a novel synaptogenic pathway for cortical neurons induced by murine and human astrocytes. By combining gain and loss of function approaches, we show that TGF-β1 induces the formation of functional synapses in mice. Further, TGF-β1-induced synaptogenesis involves neuronal activity and secretion of the co-agonist of the NMDA receptor, d-serine. Manipulation of d-serine signaling, by either genetic or pharmacological inhibition, prevented the TGF-β1 synaptogenic effect. Our data show a novel molecular mechanism that might impact synaptic function and emphasize the evolutionary aspect of the synaptogenic property of astrocytes, thus shedding light on new potential therapeutic targets for synaptic deficit diseases.
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Affiliation(s)
- Luan Pereira Diniz
- Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, 21941-590 Rio de Janeiro, RJ, Brazil
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Chen Y, Fu AKY, Ip NY. Eph receptors at synapses: implications in neurodegenerative diseases. Cell Signal 2011; 24:606-11. [PMID: 22120527 DOI: 10.1016/j.cellsig.2011.11.016] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2011] [Accepted: 11/05/2011] [Indexed: 12/16/2022]
Abstract
Precise regulation of synapse formation, maintenance and plasticity is crucial for normal cognitive function, and synaptic failure has been suggested as one of the hallmarks of neurodegenerative diseases. In this review, we describe the recent progress in our understanding of how the receptor tyrosine kinase Ephs and their ligands ephrins regulate dendritic spine morphogenesis, synapse formation and maturation, as well as synaptic plasticity. In particular, we discuss the emerging evidence implicating that deregulation of Eph/ephrin signaling contributes to the aberrant synaptic functions associated with cognitive impairment in Alzheimer's disease. Understanding how Eph/ephrin regulates synaptic function may therefore provide new insights into the development of therapeutic agents against neurodegenerative diseases.
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Affiliation(s)
- Yu Chen
- Divison of Life Science, State Key Laboratory of Molecular Neuroscience and Molecular Neuroscience Center, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China.
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