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Cabrera-Muñoz EA, Ramírez-Rodríguez GB, Díaz-Yañez L, Reyes-Galindo V, Meneses-San Juan D, Vega-Rivera NM. Melatonin Prevents Depression but Not Anxiety-like Behavior Produced by the Chemotherapeutic Agent Temozolomide: Implication of Doublecortin Cells and Hilar Oligodendrocytes. Int J Mol Sci 2023; 24:13376. [PMID: 37686181 PMCID: PMC10487426 DOI: 10.3390/ijms241713376] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2023] [Revised: 07/15/2023] [Accepted: 08/18/2023] [Indexed: 09/10/2023] Open
Abstract
Melatonin is a hormone synthesized by the pineal gland with neuroprotective and neurodevelopmental effects. Also, melatonin acts as an antidepressant by modulating the generation of new neurons in the dentate gyrus of the hippocampus. The positive effects of melatonin on behavior and neural development may suggest it is used for reverting stress but also for the alterations produced by chemotherapeutic drugs influencing behavior and brain plasticity. In this sense, temozolomide, an alkylating/anti-proliferating agent used in treating brain cancer, is associated with decreased cognitive functions and depression. We hypothesized that melatonin might prevent the effects of temozolomide on depression- and anxiety-like behavior by modulating some aspects of the neurogenic process in adult Balb/C mice. Mice were treated with temozolomide (25 mg/kg) for three days of two weeks, followed by melatonin (8 mg/kg) for fourteen days. Temozolomide produced short- and long-term decrements in cell proliferation (Ki67-positive cells: 54.89% and 53.38%, respectively) and intermediate stages of the neurogenic process (doublecortin-positive cells: 68.23% and 50.08%, respectively). However, melatonin prevented the long-term effects of temozolomide with the increased number of doublecortin-positive cells (47.21%) and the immunoreactivity of 2' 3'-Cyclic-nucleotide-3 phosphodiesterase (CNPase: 82.66%), an enzyme expressed by mature oligodendrocytes, in the hilar portion of the dentate gyrus. The effects of melatonin in the temozolomide group occurred with decreased immobility in the forced swim test (45.55%) but not anxiety-like behavior. Thus, our results suggest that melatonin prevents the harmful effects of temozolomide by modulating doublecortin cells, hilar oligodendrocytes, and depression-like behavior tested in the forced swim test. Our study could point out melatonin's beneficial effects for counteracting temozolomide's side effects.
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Affiliation(s)
- Edith Araceli Cabrera-Muñoz
- Laboratorio de Neurogénesis, Subdirección de Investigaciones Clínicas, Instituto Nacional de Psiquiatría “Ramón de la Fuente Muñiz”, Calzada Mexico-Xochimilco 101, Ciudad de México 14370, Mexico (D.M.-S.J.)
| | - Gerardo Bernabé Ramírez-Rodríguez
- Laboratorio de Neurogénesis, Subdirección de Investigaciones Clínicas, Instituto Nacional de Psiquiatría “Ramón de la Fuente Muñiz”, Calzada Mexico-Xochimilco 101, Ciudad de México 14370, Mexico (D.M.-S.J.)
| | - Lizeth Díaz-Yañez
- Laboratorio de Neurogénesis, Subdirección de Investigaciones Clínicas, Instituto Nacional de Psiquiatría “Ramón de la Fuente Muñiz”, Calzada Mexico-Xochimilco 101, Ciudad de México 14370, Mexico (D.M.-S.J.)
| | - Verónica Reyes-Galindo
- Instituto de Ecología, Universidad Nacional Autónoma de México, Circuito Exterior sin Número, Ciudad Universitaria, Ciudad de México 04510, Mexico
| | - David Meneses-San Juan
- Laboratorio de Neurogénesis, Subdirección de Investigaciones Clínicas, Instituto Nacional de Psiquiatría “Ramón de la Fuente Muñiz”, Calzada Mexico-Xochimilco 101, Ciudad de México 14370, Mexico (D.M.-S.J.)
| | - Nelly Maritza Vega-Rivera
- Laboratorio de Neurpsicofarmacología, Dirección de Neurociencias, Instituto Nacional de Psiquiatría “Ramón de la Fuente Muñiz”, Calzada Mexico-Xochimilco 101, Ciudad de México 14370, Mexico;
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Gala DS, Titlow JS, Teodoro RO, Davis I. Far from home: the role of glial mRNA localization in synaptic plasticity. RNA (NEW YORK, N.Y.) 2023; 29:153-169. [PMID: 36442969 PMCID: PMC9891262 DOI: 10.1261/rna.079422.122] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Neurons and glia are highly polarized cells, whose distal cytoplasmic functional subdomains require specific proteins. Neurons have axonal and dendritic cytoplasmic extensions containing synapses whose plasticity is regulated efficiently by mRNA transport and localized translation. The principles behind these mechanisms are equally attractive for explaining rapid local regulation of distal glial cytoplasmic projections, independent of their cell nucleus. However, in contrast to neurons, mRNA localization has received little experimental attention in glia. Nevertheless, there are many functionally diverse glial subtypes containing extensive networks of long cytoplasmic projections with likely localized regulation that influence neurons and their synapses. Moreover, glia have many other neuron-like properties, including electrical activity, secretion of gliotransmitters and calcium signaling, influencing, for example, synaptic transmission, plasticity and axon pruning. Here, we review previous studies concerning glial transcripts with important roles in influencing synaptic plasticity, focusing on a few cases involving localized translation. We discuss a variety of important questions about mRNA transport and localized translation in glia that remain to be addressed, using cutting-edge tools already available for neurons.
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Affiliation(s)
- Dalia S Gala
- Department of Biochemistry, The University of Oxford, Oxford OX1 3QU, United Kingdom
| | - Joshua S Titlow
- Department of Biochemistry, The University of Oxford, Oxford OX1 3QU, United Kingdom
| | - Rita O Teodoro
- iNOVA4Health, NOVA Medical School-Faculdade de Ciências Médicas, Universidade Nova de Lisboa, Lisboa 1169-056, Portugal
| | - Ilan Davis
- Department of Biochemistry, The University of Oxford, Oxford OX1 3QU, United Kingdom
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Zhao N, Huang W, Cãtãlin B, Scheller A, Kirchhoff F. L-Type Ca 2+ Channels of NG2 Glia Determine Proliferation and NMDA Receptor-Dependent Plasticity. Front Cell Dev Biol 2021; 9:759477. [PMID: 34746151 PMCID: PMC8567174 DOI: 10.3389/fcell.2021.759477] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Accepted: 09/16/2021] [Indexed: 12/25/2022] Open
Abstract
NG2 (nerve/glial antigen 2) glia are uniformly distributed in the gray and white matter of the central nervous system (CNS). They are the major proliferating cells in the brain and can differentiate into oligodendrocytes. NG2 glia do not only receive synaptic input from excitatory and inhibitory neurons, but also secrete growth factors and cytokines, modulating CNS homeostasis. They express several receptors and ion channels that play a role in rapidly responding upon synaptic signals and generating fast feedback, potentially regulating their own properties. Ca2+ influx via voltage-gated Ca2+ channels (VGCCs) induces an intracellular Ca2+ rise initiating a series of cellular activities. We confirmed that NG2 glia express L-type VGCCs in the white and gray matter during CNS development, particularly in the early postnatal stage. However, the function of L-type VGCCs in NG2 glia remains elusive. Therefore, we deleted L-type VGCC subtypes Cav1.2 and Cav1.3 genes conditionally in NG2 glia by crossbreeding NG2-CreERT2 knock-in mice to floxed Cav1.2 and flexed Cav1.3 transgenic mice. Our results showed that ablation of Cav1.2 and Cav1.3 strongly inhibited the proliferation of cortical NG2 glia, while differentiation in white and gray matter was not affected. As a consequence, no difference on myelination could be detected in various brain regions. In addition, we observed morphological alterations of the nodes of Ranvier induced by VGCC-deficient NG2 glia, i.e., shortened paired paranodes in the corpus callosum. Furthermore, deletion of Cav1.2 and Cav1.3 largely eliminated N-methyl-D-aspartate (NMDA)-dependent long-term depression (LTD) and potentiation in the hippocampus while the synaptic input to NG2 glia from axons remained unaltered. We conclude that L-type VGCCs of NG2 glia are essential for cell proliferation and proper structural organization of nodes of Ranvier, but not for differentiation and myelin compaction. In addition, L-type VGCCs of NG2 glia contribute to the regulation of long-term neuronal plasticity.
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Affiliation(s)
- Na Zhao
- Molecular Physiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), University of Saarland, Homburg, Germany
| | - Wenhui Huang
- Molecular Physiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), University of Saarland, Homburg, Germany
| | - Bogdan Cãtãlin
- Molecular Physiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), University of Saarland, Homburg, Germany.,Experimental Research Center for Normal and Pathological Aging, University of Medicine and Pharmacy of Craiova, Craiova, Romania
| | - Anja Scheller
- Molecular Physiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), University of Saarland, Homburg, Germany
| | - Frank Kirchhoff
- Molecular Physiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), University of Saarland, Homburg, Germany.,Experimental Research Center for Normal and Pathological Aging, University of Medicine and Pharmacy of Craiova, Craiova, Romania
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Otsu M, Ahmed Z, Fulton D. Generation of Multipotential NG2 Progenitors From Mouse Embryonic Stem Cell-Derived Neural Stem Cells. Front Cell Dev Biol 2021; 9:688283. [PMID: 34504841 PMCID: PMC8423355 DOI: 10.3389/fcell.2021.688283] [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: 03/30/2021] [Accepted: 07/02/2021] [Indexed: 11/13/2022] Open
Abstract
Embryonic stem cells (ESC) have the potential to generate homogeneous immature cells like stem/progenitor cells, which appear to be difficult to isolate and expand from primary tissue samples. In this study, we developed a simple method to generate homogeneous immature oligodendrocyte (OL) lineage cells from mouse ESC-derived neural stem cell (NSC). NSC converted to NG2+/OLIG2+double positive progenitors (NOP) after culturing in serum-free media for a week. NOP expressed Prox1, but not Gpr17 gene, highlighting their immature phenotype. Interestingly, FACS analysis revealed that NOP expressed proteins for NG2, but not PDGFRɑ, distinguishing them from primary OL progenitor cells (OPC). Nevertheless, NOP expressed various OL lineage marker genes including Cspg4, Pdgfrα, Olig1/2, and Sox9/10, but not Plp1 genes, and, when cultured in OL differentiation conditions, initiated transcription of Gpr17 and Plp1 genes, and expression of PDGFRα proteins, implying that NOP converted into a matured OPC phenotype. Unexpectedly, NOP remained multipotential, being able to differentiate into neurons as well as astrocytes under appropriate conditions. Moreover, NOP-derived OPC myelinated axons with a lower efficiency when compared with primary OPC. Taken together, these data demonstrate that NOP are an intermediate progenitor cell distinguishable from both NSC and primary OPC. Based on this profile, NOP may be useful for modeling mechanisms influencing the earliest stages of oligogenesis, and exploring the cellular and molecular responses of the earliest OL progenitors to conditions that impair myelination in the developing nervous system.
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Affiliation(s)
- Masahiro Otsu
- Neuroscience and Ophthalmology Research Group, Institute of Inflammation and Ageing, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Zubair Ahmed
- Neuroscience and Ophthalmology Research Group, Institute of Inflammation and Ageing, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Daniel Fulton
- Neuroscience and Ophthalmology Research Group, Institute of Inflammation and Ageing, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
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Semyanov A, Verkhratsky A. Astrocytic processes: from tripartite synapses to the active milieu. Trends Neurosci 2021; 44:781-792. [PMID: 34479758 DOI: 10.1016/j.tins.2021.07.006] [Citation(s) in RCA: 110] [Impact Index Per Article: 36.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Revised: 07/09/2021] [Accepted: 07/20/2021] [Indexed: 12/16/2022]
Abstract
We define a new concept of 'active milieu' that unifies all components of nervous tissue (neuronal and glial compartments, extracellular space, extracellular matrix, and vasculature) into a dynamic information processing system. Within this framework, we focus on the role of astrocytic processes, classified into organelle-containing branches and organelle-free leaflets. We argue that astrocytic branches with emanating leaflets are homologous to dendritic shafts with spines. Within the active milieu, astrocytic processes are engaged in reciprocal interactions with neuronal compartments and communication with other cellular and non-cellular elements of the nervous tissue.
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Affiliation(s)
- Alexey Semyanov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, 117997, Russia; Faculty of Biology, Moscow State University, Moscow, Russia; Sechenov First Moscow State Medical University, Moscow, Russia.
| | - Alexei Verkhratsky
- Sechenov First Moscow State Medical University, Moscow, Russia; Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK; Achucarro Center for Neuroscience, IKERBASQUE, Basque Foundation for Science, 48011 Bilbao, Spain; Department of Neurosciences, University of the Basque Country UPV/EHU and CIBERNED, Leioa, Spain.
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Hayes AJ, Melrose J. Neural Tissue Homeostasis and Repair Is Regulated via CS and DS Proteoglycan Motifs. Front Cell Dev Biol 2021; 9:696640. [PMID: 34409033 PMCID: PMC8365427 DOI: 10.3389/fcell.2021.696640] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Accepted: 07/13/2021] [Indexed: 01/04/2023] Open
Abstract
Chondroitin sulfate (CS) is the most abundant and widely distributed glycosaminoglycan (GAG) in the human body. As a component of proteoglycans (PGs) it has numerous roles in matrix stabilization and cellular regulation. This chapter highlights the roles of CS and CS-PGs in the central and peripheral nervous systems (CNS/PNS). CS has specific cell regulatory roles that control tissue function and homeostasis. The CNS/PNS contains a diverse range of CS-PGs which direct the development of embryonic neural axonal networks, and the responses of neural cell populations in mature tissues to traumatic injury. Following brain trauma and spinal cord injury, a stabilizing CS-PG-rich scar tissue is laid down at the defect site to protect neural tissues, which are amongst the softest tissues of the human body. Unfortunately, the CS concentrated in gliotic scars also inhibits neural outgrowth and functional recovery. CS has well known inhibitory properties over neural behavior, and animal models of CNS/PNS injury have demonstrated that selective degradation of CS using chondroitinase improves neuronal functional recovery. CS-PGs are present diffusely in the CNS but also form denser regions of extracellular matrix termed perineuronal nets which surround neurons. Hyaluronan is immobilized in hyalectan CS-PG aggregates in these perineural structures, which provide neural protection, synapse, and neural plasticity, and have roles in memory and cognitive learning. Despite the generally inhibitory cues delivered by CS-A and CS-C, some CS-PGs containing highly charged CS disaccharides (CS-D, CS-E) or dermatan sulfate (DS) disaccharides that promote neural outgrowth and functional recovery. CS/DS thus has varied cell regulatory properties and structural ECM supportive roles in the CNS/PNS depending on the glycoform present and its location in tissue niches and specific cellular contexts. Studies on the fruit fly, Drosophila melanogaster and the nematode Caenorhabditis elegans have provided insightful information on neural interconnectivity and the role of the ECM and its PGs in neural development and in tissue morphogenesis in a whole organism environment.
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Affiliation(s)
- Anthony J. Hayes
- Bioimaging Research Hub, Cardiff School of Biosciences, Cardiff University, Wales, United Kingdom
| | - James Melrose
- Graduate School of Biomedical Engineering, University of New South Wales, Sydney, NSW, Australia
- Raymond Purves Bone and Joint Research Laboratories, Kolling Institute of Medical Research, Royal North Shore Hospital and The Faculty of Medicine and Health, The University of Sydney, St. Leonard’s, NSW, Australia
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A morphological analysis of activity-dependent myelination and myelin injury in transitional oligodendrocytes. Sci Rep 2021; 11:9588. [PMID: 33953273 PMCID: PMC8099889 DOI: 10.1038/s41598-021-88887-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Accepted: 04/07/2021] [Indexed: 12/13/2022] Open
Abstract
Neuronal activity is established as a driver of oligodendrocyte (OL) differentiation and myelination. The concept of activity-dependent myelin plasticity, and its role in cognition and disease, is gaining support. Methods capable of resolving changes in the morphology of individual myelinating OL would advance our understanding of myelin plasticity and injury, thus we adapted a labelling approach involving Semliki Forest Virus (SFV) vectors to resolve and quantify the 3-D structure of OL processes and internodes in cerebellar slice cultures. We first demonstrate the utility of the approach by studying changes in OL morphology after complement-mediated injury. SFV vectors injected into cerebellar white matter labelled transitional OL (TOL), whose characteristic mixture of myelinating and non-myelinating processes exhibited significant degeneration after complement injury. The method was also capable of resolving finer changes in morphology related to neuronal activity. Prolonged suppression of neuronal activity, which reduced myelination, selectively decreased the length of putative internodes, and the proportion of process branches that supported them, while leaving other features of process morphology unaltered. Overall this work provides novel information on the morphology of TOL, and their response to conditions that alter circuit function or induce demyelination.
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Ceprian M, Fulton D. Glial Cell AMPA Receptors in Nervous System Health, Injury and Disease. Int J Mol Sci 2019; 20:ijms20102450. [PMID: 31108947 PMCID: PMC6566241 DOI: 10.3390/ijms20102450] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Revised: 04/11/2019] [Accepted: 04/22/2019] [Indexed: 12/16/2022] Open
Abstract
Glia form a central component of the nervous system whose varied activities sustain an environment that is optimised for healthy development and neuronal function. Alpha-amino-3-hydroxy-5-methyl-4-isoxazole (AMPA)-type glutamate receptors (AMPAR) are a central mediator of glutamatergic excitatory synaptic transmission, yet they are also expressed in a wide range of glial cells where they influence a variety of important cellular functions. AMPAR enable glial cells to sense the activity of neighbouring axons and synapses, and as such many aspects of glial cell development and function are influenced by the activity of neural circuits. However, these AMPAR also render glia sensitive to elevations of the extracellular concentration of glutamate, which are associated with a broad range of pathological conditions. Excessive activation of AMPAR under these conditions may induce excitotoxic injury in glial cells, and trigger pathophysiological responses threatening other neural cells and amplifying ongoing disease processes. The aim of this review is to gather information on AMPAR function from across the broad diversity of glial cells, identify their contribution to pathophysiological processes, and highlight new areas of research whose progress may increase our understanding of nervous system dysfunction and disease.
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Affiliation(s)
- Maria Ceprian
- Instituto de Investigación Sanitaria San Carlos (IdISSC), 28040 Madrid, Spain.
- Departamento de Bioquímica y Biología Molecular, CIBERNED, IRICYS. Facultad de Medicina, Universidad Complutense de Madrid, 28040 Madrid, Spain.
| | - Daniel Fulton
- Neuroscience and Ophthalmology Research Group, Institute of Inflammation and Ageing, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK.
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Sehmbi M, Rowley CD, Minuzzi L, Kapczinski F, Kwiecien JM, Bock NA, Frey BN. Age-related deficits in intracortical myelination in young adults with bipolar disorder type I. J Psychiatry Neurosci 2019; 44:79-88. [PMID: 30525334 PMCID: PMC6397039 DOI: 10.1503/jpn.170220] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND Previous studies have implicated white-matter-related changes in the pathophysiology of bipolar disorder. However, most of what is known is derived from in vivo subcortical white-matter imaging or postmortem studies. In this study, we investigated whole-brain intracortical myelin (ICM) content in people with bipolar disorder type I and controls. METHODS Between Sept. 1, 2014, and Jan. 31, 2017, we used a 3 T General Electric scanner to collect T1-weighted images in 45 people with bipolar disorder type I and 60 controls aged 17 to 45 years using an optimized sequence that was sensitive to ICM content. We analyzed images using a surfacebased approach. We used general linear models with quadratic age terms to examine the signal trajectory of ICM across the age range. RESULTS In healthy controls, the T1-weighted signal followed an inverted-U trajectory over age; in people with bipolar disorder type I, the association between ICM and age followed a flat trajectory (p < 0.05, Bonferroni corrected). Exploratory analyses showed that ICM signal intensity was associated with duration of illness, age of onset, and anticonvulsant and antipsychotic use in people with bipolar disorder type I (p < 0.05, uncorrected). LIMITATIONS Because of the cross-sectional nature of the study, we were unable to comment on whether the effects were due to dysmyelination or demyelination in bipolar disorder. CONCLUSION This foundational study is, to our knowledge, the first to show global age-related deficits in ICM maturation throughout the cortex in bipolar disorder. Considering the impact of myelination on the maintenance of neural synchrony and the integrity of neural connections, this work may help us better understand the cognitive and behavioural deficits seen in bipolar disorder.
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Affiliation(s)
- Manpreet Sehmbi
- From the Graduate Student, MiNDS Neuroscience Graduate Program, McMaster University, Hamilton, ON (Sehmbi, Rowley); the Mood Disorders Program, Department of Psychiatry and Behavioural Neurosciences, McMaster University, Hamilton, ON (Minuzzi, Kapczinski, Frey); the Women’s Health Concerns Clinic, St. Joseph’s Healthcare, Hamilton, ON (Minuzzi, Frey); the Department of Pathology and Molecular Medicine, M. deGroote School of Medicine, McMaster University, Hamilton, ON (Kwiecien); the Department of Psychology, Neuroscience, and Behaviour, McMaster University, Hamilton, ON (Bock); and the Department of Clinical Pathomorphology, Medical University of Lublin, Poland (Kwiecien)
| | - Christopher D. Rowley
- From the Graduate Student, MiNDS Neuroscience Graduate Program, McMaster University, Hamilton, ON (Sehmbi, Rowley); the Mood Disorders Program, Department of Psychiatry and Behavioural Neurosciences, McMaster University, Hamilton, ON (Minuzzi, Kapczinski, Frey); the Women’s Health Concerns Clinic, St. Joseph’s Healthcare, Hamilton, ON (Minuzzi, Frey); the Department of Pathology and Molecular Medicine, M. deGroote School of Medicine, McMaster University, Hamilton, ON (Kwiecien); the Department of Psychology, Neuroscience, and Behaviour, McMaster University, Hamilton, ON (Bock); and the Department of Clinical Pathomorphology, Medical University of Lublin, Poland (Kwiecien)
| | - Luciano Minuzzi
- From the Graduate Student, MiNDS Neuroscience Graduate Program, McMaster University, Hamilton, ON (Sehmbi, Rowley); the Mood Disorders Program, Department of Psychiatry and Behavioural Neurosciences, McMaster University, Hamilton, ON (Minuzzi, Kapczinski, Frey); the Women’s Health Concerns Clinic, St. Joseph’s Healthcare, Hamilton, ON (Minuzzi, Frey); the Department of Pathology and Molecular Medicine, M. deGroote School of Medicine, McMaster University, Hamilton, ON (Kwiecien); the Department of Psychology, Neuroscience, and Behaviour, McMaster University, Hamilton, ON (Bock); and the Department of Clinical Pathomorphology, Medical University of Lublin, Poland (Kwiecien)
| | - Flavio Kapczinski
- From the Graduate Student, MiNDS Neuroscience Graduate Program, McMaster University, Hamilton, ON (Sehmbi, Rowley); the Mood Disorders Program, Department of Psychiatry and Behavioural Neurosciences, McMaster University, Hamilton, ON (Minuzzi, Kapczinski, Frey); the Women’s Health Concerns Clinic, St. Joseph’s Healthcare, Hamilton, ON (Minuzzi, Frey); the Department of Pathology and Molecular Medicine, M. deGroote School of Medicine, McMaster University, Hamilton, ON (Kwiecien); the Department of Psychology, Neuroscience, and Behaviour, McMaster University, Hamilton, ON (Bock); and the Department of Clinical Pathomorphology, Medical University of Lublin, Poland (Kwiecien)
| | - Jacek M. Kwiecien
- From the Graduate Student, MiNDS Neuroscience Graduate Program, McMaster University, Hamilton, ON (Sehmbi, Rowley); the Mood Disorders Program, Department of Psychiatry and Behavioural Neurosciences, McMaster University, Hamilton, ON (Minuzzi, Kapczinski, Frey); the Women’s Health Concerns Clinic, St. Joseph’s Healthcare, Hamilton, ON (Minuzzi, Frey); the Department of Pathology and Molecular Medicine, M. deGroote School of Medicine, McMaster University, Hamilton, ON (Kwiecien); the Department of Psychology, Neuroscience, and Behaviour, McMaster University, Hamilton, ON (Bock); and the Department of Clinical Pathomorphology, Medical University of Lublin, Poland (Kwiecien)
| | - Nicholas A. Bock
- From the Graduate Student, MiNDS Neuroscience Graduate Program, McMaster University, Hamilton, ON (Sehmbi, Rowley); the Mood Disorders Program, Department of Psychiatry and Behavioural Neurosciences, McMaster University, Hamilton, ON (Minuzzi, Kapczinski, Frey); the Women’s Health Concerns Clinic, St. Joseph’s Healthcare, Hamilton, ON (Minuzzi, Frey); the Department of Pathology and Molecular Medicine, M. deGroote School of Medicine, McMaster University, Hamilton, ON (Kwiecien); the Department of Psychology, Neuroscience, and Behaviour, McMaster University, Hamilton, ON (Bock); and the Department of Clinical Pathomorphology, Medical University of Lublin, Poland (Kwiecien)
| | - Benicio N. Frey
- From the Graduate Student, MiNDS Neuroscience Graduate Program, McMaster University, Hamilton, ON (Sehmbi, Rowley); the Mood Disorders Program, Department of Psychiatry and Behavioural Neurosciences, McMaster University, Hamilton, ON (Minuzzi, Kapczinski, Frey); the Women’s Health Concerns Clinic, St. Joseph’s Healthcare, Hamilton, ON (Minuzzi, Frey); the Department of Pathology and Molecular Medicine, M. deGroote School of Medicine, McMaster University, Hamilton, ON (Kwiecien); the Department of Psychology, Neuroscience, and Behaviour, McMaster University, Hamilton, ON (Bock); and the Department of Clinical Pathomorphology, Medical University of Lublin, Poland (Kwiecien)
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Wellman SM, Cambi F, Kozai TD. The role of oligodendrocytes and their progenitors on neural interface technology: A novel perspective on tissue regeneration and repair. Biomaterials 2018; 183:200-217. [PMID: 30172245 PMCID: PMC6469877 DOI: 10.1016/j.biomaterials.2018.08.046] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Revised: 08/08/2018] [Accepted: 08/20/2018] [Indexed: 12/11/2022]
Abstract
Oligodendrocytes and their precursors are critical glial facilitators of neurophysiology, which is responsible for cognition and behavior. Devices that are used to interface with the brain allow for a more in-depth analysis of how neurons and these glia synergistically modulate brain activity. As projected by the BRAIN Initiative, technologies that acquire a high resolution and robust sampling of neural signals can provide a greater insight in both the healthy and diseased brain and support novel discoveries previously unobtainable with the current state of the art. However, a complex series of inflammatory events triggered during device insertion impede the potential applications of implanted biosensors. Characterizing the biological mechanisms responsible for the degradation of intracortical device performance will guide novel biomaterial and tissue regenerative approaches to rehabilitate the brain following injury. Glial subtypes which assist with neuronal survival and exchange of electrical signals, mainly oligodendrocytes, their precursors, and the insulating myelin membranes they produce, are sensitive to inflammation commonly induced from insults to the brain. This review explores essential physiological roles facilitated by oligodendroglia and their precursors and provides insight into their pathology following neurodegenerative injury and disease. From this knowledge, inferences can be made about the impact of device implantation on these supportive glia in order to engineer effective strategies that can attenuate their responses, enhance the efficacy of neural interfacing technology, and provide a greater understanding of the challenges that impede wound healing and tissue regeneration during pathology.
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Affiliation(s)
- Steven M Wellman
- Department of Bioengineering, University of Pittsburgh, USA; Center for the Neural Basis of Cognition, Pittsburgh, PA, USA
| | - Franca Cambi
- Veterans Administration Pittsburgh, Pittsburgh, PA, USA; Department of Neurology, University of Pittsburgh, USA
| | - Takashi Dy Kozai
- Department of Bioengineering, University of Pittsburgh, USA; Center for the Neural Basis of Cognition, Pittsburgh, PA, USA; Center for Neuroscience, University of Pittsburgh, USA; McGowan Institute of Regenerative Medicine, University of Pittsburgh, USA; NeuroTech Center, University of Pittsburgh Brain Institute, USA.
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Gómez-Pinedo U, Duran-Moreno M, Sirerol-Piquer S, Matias-Guiu J. Myelin changes in Alexander disease. NEUROLOGÍA (ENGLISH EDITION) 2018. [DOI: 10.1016/j.nrleng.2017.01.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022] Open
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12
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Káradóttir RT, Kuo CT. Neuronal Activity-Dependent Control of Postnatal Neurogenesis and Gliogenesis. Annu Rev Neurosci 2018; 41:139-161. [PMID: 29618286 DOI: 10.1146/annurev-neuro-072116-031054] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The addition of new neurons and oligodendroglia in the postnatal and adult mammalian brain presents distinct forms of gray and white matter plasticity. Substantial effort has been devoted to understanding the cellular and molecular mechanisms controlling postnatal neurogenesis and gliogenesis, revealing important parallels to principles governing the embryonic stages. While during central nervous system development, scripted temporal and spatial patterns of neural and glial progenitor proliferation and differentiation are necessary to create the nervous system architecture, it remains unclear what driving forces maintain and sustain postnatal neural stem cell (NSC) and oligodendrocyte progenitor cell (OPC) production of new neurons and glia. In recent years, neuronal activity has been identified as an important modulator of these processes. Using the distinct properties of neurotransmitter ionotropic and metabotropic channels to signal downstream cellular events, NSCs and OPCs share common features in their readout of neuronal activity patterns. Here we review the current evidence for neuronal activity-dependent control of NSC/OPC proliferation and differentiation in the postnatal brain, highlight some potential mechanisms used by the two progenitor populations, and discuss future studies that might advance these research areas further.
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Affiliation(s)
- Ragnhildur T Káradóttir
- Wellcome Trust - Medical Research Council Cambridge Stem Cell Institute, University of Cambridge, Cambridge CB2 1QR, United Kingdom; .,Department of Veterinary Medicine, University of Cambridge, Cambridge CB3 0ES, United Kingdom
| | - Chay T Kuo
- Departments of Cell Biology and Neurobiology, Duke University School of Medicine, Durham, North Carolina 27710, USA; .,Preston Robert Tisch Brain Tumor Center, Duke University Medical Center, Durham, North Carolina 27710, USA.,Institute for Brain Sciences, Duke University, Durham, North Carolina 27708, USA
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13
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Gómez-Pinedo U, Duran-Moreno M, Sirerol-Piquer S, Matias-Guiu J. Myelin changes in Alexander disease. Neurologia 2017; 33:526-533. [PMID: 28342553 DOI: 10.1016/j.nrl.2017.01.019] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2017] [Accepted: 01/26/2017] [Indexed: 12/30/2022] Open
Abstract
INTRODUCTION Alexander disease (AxD) is a type of leukodystrophy. Its pathological basis, along with myelin loss, is the appearance of Rosenthal bodies, which are cytoplasmic inclusions in astrocytes. Mutations in the gene coding for GFAP have been identified as a genetic basis for AxD. However, the mechanism by which these variants produce the disease is not understood. DEVELOPMENT The most widespread hypothesis is that AxD develops when a gain of function mutation causes an increase in GFAP. However, this mechanism does not explain myelin loss, given that experimental models in which GFAP expression is normal or mutated do not exhibit myelin disorders. This review analyses other possibilities that may explain this alteration, such as epigenetic or inflammatory alterations, presence of NG2 (+) - GFAP (+) cells, or post-translational modifications in GFAP that are unrelated to increased expression. CONCLUSIONS The different hypotheses analysed here may explain the myelin alteration affecting these patients, and multiple mechanisms may coexist. These theories raise the possibility of designing therapies based on these mechanisms.
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Affiliation(s)
- U Gómez-Pinedo
- Laboratorio de Neurobiología, Servicio de Neurología, Instituto de Neurociencias, IdISSC, Hospital Clínico San Carlos, Universidad Complutense de Madrid, Madrid, España.
| | - M Duran-Moreno
- Laboratorio de Neurobiología Comparada, Instituto Cavanilles de Biodiversidad y Biología Evolutiva, Universidad de Valencia, Valencia, España
| | - S Sirerol-Piquer
- Laboratorio de Neurobiología Comparada, Instituto Cavanilles de Biodiversidad y Biología Evolutiva, Universidad de Valencia, Valencia, España
| | - J Matias-Guiu
- Laboratorio de Neurobiología, Servicio de Neurología, Instituto de Neurociencias, IdISSC, Hospital Clínico San Carlos, Universidad Complutense de Madrid, Madrid, España
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14
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Astrocyte Sodium Signalling and Panglial Spread of Sodium Signals in Brain White Matter. Neurochem Res 2017; 42:2505-2518. [PMID: 28214986 DOI: 10.1007/s11064-017-2197-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Revised: 01/19/2017] [Accepted: 01/28/2017] [Indexed: 10/20/2022]
Abstract
In brain grey matter, excitatory synaptic transmission activates glutamate uptake into astrocytes, inducing sodium signals which propagate into neighboring astrocytes through gap junctions. These sodium signals have been suggested to serve an important role in neuro-metabolic coupling. So far, it is unknown if astrocytes in white matter-that is in brain regions devoid of synapses-are also able to undergo such intra- and intercellular sodium signalling. In the present study, we have addressed this question by performing quantitative sodium imaging in acute tissue slices of mouse corpus callosum. Focal application of glutamate induced sodium transients in SR101-positive astrocytes. These were largely unaltered in the presence of ionotropic glutamate receptors blockers, but strongly dampened upon pharmacological inhibition of glutamate uptake. Sodium signals induced in individual astrocytes readily spread into neighboring SR101-positive cells with peak amplitudes decaying monoexponentially with distance from the stimulated cell. In addition, spread of sodium was largely unaltered during pharmacological inhibition of purinergic and glutamate receptors, indicating gap junction-mediated, passive diffusion of sodium between astrocytes. Using cell-type-specific, transgenic reporter mice, we found that sodium signals also propagated, albeit less effectively, from astrocytes to neighboring oligodendrocytes and NG2 cells. Again, panglial spread was unaltered with purinergic and glutamate receptors blocked. Taken together, our results demonstrate that activation of sodium-dependent glutamate transporters induces sodium signals in white matter astrocytes, which spread within the astrocyte syncytium. In addition, we found a panglial passage of sodium signals from astrocytes to NG2 cells and oligodendrocytes, indicating functional coupling between these macroglial cells in white matter.
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15
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Aging affects new cell production in the adult hippocampus: A quantitative anatomic review. J Chem Neuroanat 2015; 76:64-72. [PMID: 26686289 DOI: 10.1016/j.jchemneu.2015.10.009] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2015] [Revised: 08/08/2015] [Accepted: 10/19/2015] [Indexed: 02/08/2023]
Abstract
In the last century, cognitive impairment in elderly people was considered as the consequence of neuronal death. However, later analyses indicated that age-related reduction in neuron number was limited to specific regions of the central nervous system, and was irrelevant to brain dysfunction in both humans and non-human animals. Recent studies have indicated that progressive diminution of neural plasticity across an individual's life span may underlie age-related brain dysfunction. To date, various factors have been shown to contribute to neural plasticity. In particular, substantial data supports the importance of production of new cells in the adult brain: the rate of hippocampal neurogenesis wanes radically during aging; similarly, white matter homeostasis via oligodendrogenesis is also affected by aging. This review briefly summarizes quantitative studies on adult hippocampal neurogenesis and oligodendrogenesis. Although the hippocampus is traditionally recognized as the memory center of the brain, it has started to emerge as an integrator of cognition and emotion. One of the current research highlights is that diverse functions of the hippocampus are topographically embedded along its longitudinal and transverse axes. Here we discuss alterations in adult neurogenesis and oligodendrogenesis during aging from a topographic view point. The quantitative anatomic approach to age-related alterations in production of new cells in the hippocampus may give a novel insight into how brain functions suffer from aging.
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16
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Birey F, Kloc M, Chavali M, Hussein I, Wilson M, Christoffel DJ, Chen T, Frohman MA, Robinson JK, Russo SJ, Maffei A, Aguirre A. Genetic and Stress-Induced Loss of NG2 Glia Triggers Emergence of Depressive-like Behaviors through Reduced Secretion of FGF2. Neuron 2015; 88:941-956. [PMID: 26606998 PMCID: PMC5354631 DOI: 10.1016/j.neuron.2015.10.046] [Citation(s) in RCA: 122] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Revised: 09/29/2015] [Accepted: 10/28/2015] [Indexed: 01/25/2023]
Abstract
NG2-expressing glia (NG2 glia) are a uniformly distributed and mitotically active pool of cells in the central nervous system (CNS). In addition to serving as progenitors of myelinating oligodendrocytes, NG2 glia might also fulfill physiological roles in CNS homeostasis, although the mechanistic nature of such roles remains unclear. Here, we report that ablation of NG2 glia in the prefrontal cortex (PFC) of the adult brain causes deficits in excitatory glutamatergic neurotransmission and astrocytic extracellular glutamate uptake and induces depressive-like behaviors in mice. We show in parallel that chronic social stress causes NG2 glia density to decrease in areas critical to Major Depressive Disorder (MDD) pathophysiology at the time of symptom emergence in stress-susceptible mice. Finally, we demonstrate that loss of NG2 glial secretion of fibroblast growth factor 2 (FGF2) suffices to induce the same behavioral deficits. Our findings outline a pathway and role for NG2 glia in CNS homeostasis and mood disorders.
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Affiliation(s)
- Fikri Birey
- Department of Pharmacological Sciences, Stony Brook University, Stony Brook, NY 11794, USA; Graduate Program in Genetics, Stony Brook University, Stony Brook, NY 11794, USA
| | - Michelle Kloc
- Department of Neurobiology and Behavior, Stony Brook University, Stony Brook, NY 11794, USA
| | - Manideep Chavali
- Department of Pharmacological Sciences, Stony Brook University, Stony Brook, NY 11794, USA; Department of Materials Science and Engineering, Stony Brook University, Stony Brook, NY 11794, USA
| | - Israa Hussein
- Department of Pharmacological Sciences, Stony Brook University, Stony Brook, NY 11794, USA
| | - Michael Wilson
- Department of Pharmacological Sciences, Stony Brook University, Stony Brook, NY 11794, USA
| | - Daniel J Christoffel
- Fishberg Department of Neuroscience and Friedman Brain Institute, Mount Sinai School of Medicine, New York, NY 10029, USA
| | - Tony Chen
- Department of Pharmacological Sciences, Stony Brook University, Stony Brook, NY 11794, USA
| | - Michael A Frohman
- Department of Pharmacological Sciences, Stony Brook University, Stony Brook, NY 11794, USA
| | - John K Robinson
- Department of Psychology, Stony Brook University, Stony Brook, NY 11794, USA
| | - Scott J Russo
- Fishberg Department of Neuroscience and Friedman Brain Institute, Mount Sinai School of Medicine, New York, NY 10029, USA
| | - Arianna Maffei
- Department of Neurobiology and Behavior, Stony Brook University, Stony Brook, NY 11794, USA
| | - Adan Aguirre
- Department of Pharmacological Sciences, Stony Brook University, Stony Brook, NY 11794, USA.
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17
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Dimou L, Gallo V. NG2-glia and their functions in the central nervous system. Glia 2015; 63:1429-51. [PMID: 26010717 DOI: 10.1002/glia.22859] [Citation(s) in RCA: 173] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2015] [Accepted: 05/04/2015] [Indexed: 12/12/2022]
Abstract
In the central nervous system, NG2-glia represent a neural cell population that is distinct from neurons, astrocytes, and oligodendrocytes. While in the past the main role ascribed to these cells was that of progenitors for oligodendrocytes, in the last years it has become more obvious that they have further functions in the brain. Here, we will discuss some of the most current and highly debated issues regarding NG2-glia: Do these cells represent a heterogeneous population? Can they give rise to different progenies, and does this change under pathological conditions? How do they respond to injury or pathology? What is the role of neurotransmitter signaling between neurons and NG2-glia? We will first give an overview on the developmental origin of NG2-glia, and then discuss whether their distinct properties in different brain regions are the result of environmental influences, or due to intrinsic differences. We will then review and discuss their in vitro differentiation potential and in vivo lineage under physiological and pathological conditions, together with their electrophysiological properties in distinct brain regions and at different developmental stages. Finally, we will focus on their potential to be used as therapeutic targets in demyelinating and neurodegenerative diseases. Therefore, this review article will highlight the importance of NG2-glia not only in the healthy, but also in the diseased brain.
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Affiliation(s)
- L Dimou
- Physiological Genomics, Biomedical Center, Ludwig-Maximilians University, Munich, 80336, Germany.,Institute for Stem Cell Research, Helmholtz Zentrum Munich, Neuherberg, 85764, Germany
| | - V Gallo
- Center for Neuroscience Research, Children's Research Institute, Children's National Medical Center, Washington, District of Columbia
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18
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Somkuwar SS, Staples MC, Galinato MH, Fannon MJ, Mandyam CD. Role of NG2 expressing cells in addiction: a new approach for an old problem. Front Pharmacol 2014; 5:279. [PMID: 25566075 PMCID: PMC4271769 DOI: 10.3389/fphar.2014.00279] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2014] [Accepted: 11/30/2014] [Indexed: 12/17/2022] Open
Abstract
Neuron-glial antigen 2 (NG2) is a proteoglycan expressed predominantly in oligodendrocyte progenitor cells (OPCs). NG2-expressing OPCs (NG2-OPCs) are self-renewing cells that are widely distributed in the gray and white matter areas of the central nervous system. NG2-OPCs can mature into premyelinating oligodendrocytes and myelinating oligodendroglia which serve as the primary source of myelin in the brain. This review characterizes NG2-OPCs in brain structure and function, conceptualizes the role of NG2-OPCs in brain regions associated with negative reinforcement and relapse to drug seeking and discusses how NG2-OPCs are regulated by neuromodulators linked to motivational withdrawal. We hope to provide the readers with an overview of the role of NG2-OPCs in brain structure and function in the context of negative affect state in substance abuse disorders and to integrate our current understanding of the physiological significance of the NG2-OPCs in the adult brain.
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Affiliation(s)
- Sucharita S Somkuwar
- Committee on the Neurobiology of Addictive Disorders, The Scripps Research Institute La Jolla, CA, USA
| | - Miranda C Staples
- Committee on the Neurobiology of Addictive Disorders, The Scripps Research Institute La Jolla, CA, USA
| | - Melissa H Galinato
- Committee on the Neurobiology of Addictive Disorders, The Scripps Research Institute La Jolla, CA, USA
| | - McKenzie J Fannon
- Committee on the Neurobiology of Addictive Disorders, The Scripps Research Institute La Jolla, CA, USA
| | - Chitra D Mandyam
- Committee on the Neurobiology of Addictive Disorders, The Scripps Research Institute La Jolla, CA, USA
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19
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Xiao L, Saiki C, Ide R. Stem cell therapy for central nerve system injuries: glial cells hold the key. Neural Regen Res 2014; 9:1253-60. [PMID: 25221575 PMCID: PMC4160849 DOI: 10.4103/1673-5374.137570] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/01/2014] [Indexed: 12/13/2022] Open
Abstract
Mammalian adult central nerve system (CNS) injuries are devastating because of the intrinsic difficulties for effective neuronal regeneration. The greatest problem to be overcome for CNS recovery is the poor regeneration of neurons and myelin-forming cells, oligodendrocytes. Endogenous neural progenitors and transplanted exogenous neuronal stem cells can be the source for neuronal regeneration. However, because of the harsh local microenvironment, they usually have very low efficacy for functional neural regeneration which cannot compensate for the loss of neurons and oligodendrocytes. Glial cells (including astrocytes, microglia, oligodendrocytes and NG2 glia) are the majority of cells in CNS that provide support and protection for neurons. Inside the local microenvironment, glial cells largely influence local and transplanted neural stem cells survival and fates. This review critically analyzes current finding of the roles of glial cells in CNS regeneration, and highlights strategies for regulating glial cells’ behavior to create a permissive microenvironment for neuronal stem cells.
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Affiliation(s)
- Li Xiao
- Pharmacology Department, The Nippon Dental University, School of Life Dentistry at Tokyo, Tokyo, Japan
| | - Chikako Saiki
- Physiology Department, The Nippon Dental University, School of Life Dentistry at Tokyo, Tokyo, Japan
| | - Ryoji Ide
- Physiology Department, The Nippon Dental University, School of Life Dentistry at Tokyo, Tokyo, Japan
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20
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Cadet JL, Bisagno V. Glial-neuronal ensembles: partners in drug addiction-associated synaptic plasticity. Front Pharmacol 2014; 5:204. [PMID: 25228881 PMCID: PMC4151032 DOI: 10.3389/fphar.2014.00204] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2014] [Accepted: 08/15/2014] [Indexed: 12/16/2022] Open
Affiliation(s)
- Jean Lud Cadet
- Molecular Neuropsychiatry Research Branch, Intramural Research Program, National Institute on Drug Abuse-NIH Baltimore, MD, USA
| | - Veronica Bisagno
- Instituto de Investigaciones Farmacológicas (ININFA-UBA-CONICET) Buenos Aires, Argentina
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21
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Transgenic rat model of Huntington's disease: a histopathological study and correlations with neurodegenerative process in the brain of HD patients. BIOMED RESEARCH INTERNATIONAL 2014; 2014:291531. [PMID: 25162006 PMCID: PMC4137602 DOI: 10.1155/2014/291531] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/09/2014] [Revised: 06/26/2014] [Accepted: 06/26/2014] [Indexed: 01/09/2023]
Abstract
Rats transgenic for Huntington's disease (tgHD51 CAG rats), surviving up to two years, represent an animal model of HD similar to the late-onset form of human disease. This enables us to follow histopathological changes in course of neurodegenerative process (NDP) within the striatum and compare them with postmortem samples of human HD brains. A basic difference between HD pathology in human and tgHD51 rats is in the rate of NDP progression that originates primarily from slow neuronal degeneration consequently resulting in lesser extent of concomitant reactive gliosis in the brain of tgHD51 rats. Although larger amount of striatal neurons displays only gradual decrease in their size, their number is significantly reduced in the oldest tgHD51 rats. Our quantitative analysis proved that the end of the first year represents the turn in the development of morphological changes related to the progression of NDP in tgHD51 rats. Our data also support the view that all types of CNS glial cells play an important, irreplaceable role in NDP. To the best of our knowledge, our findings are the first to document that tgHD51 CAG rats can be used as a valid animal model for detailed histopathological studies related to HD in human.
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22
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Yamada J, Jinno S. Age-related differences in oligodendrogenesis across the dorsal-ventral axis of the mouse hippocampus. Hippocampus 2014; 24:1017-29. [PMID: 24753086 DOI: 10.1002/hipo.22287] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2013] [Revised: 03/12/2014] [Accepted: 04/11/2014] [Indexed: 11/07/2022]
Abstract
Oligodendrocyte precursor cells (OPCs) continue to divide and generate new oligodendrocytes (OLs) in the healthy adult brain. Although recent studies have indicated that adult oligodendrogenesis may be vital for the maintenance of normal brain function, the significance of adult oligodendrogenesis in brain aging remains unclear. In this study, we report a stereological estimation of age-related oligodendrogenesis changes in the mouse hippocampus: the dorsal subdivision is related to learning and memory, while the ventral subdivision is involved in emotional behaviors. To identify OPCs and OLs, we used a set of molecular markers, OL lineage transcription factor (Olig2) and platelet-derived growth factor receptor-alpha (PDGFαR). Intracellular dye injection shows that PDGFαR+/Olig2+ cells and PDGFαR-/Olig2+ cells can be defined as OPCs and OLs, respectively. In the dorsal Ammon's horn, the numbers of OPCs decreased with age, while those of OLs remained unchanged during aging. In the ventral Ammon's horn, the numbers of OPCs and OLs generally decreased with age. Bromodeoxyuridine (BrdU) fate-tracing analysis revealed that the numbers of BrdU+ mitotic OPCs in the Ammon's horn remained unchanged during aging in both the dorsal and ventral subdivisions. Unexpectedly, the numbers of BrdU+ newly generated OLs increased with age in the dorsal Ammon's horn, but remained unchanged in the ventral Ammon's horn. Together, the numbers of OLs in the dorsal Ammon's horn may be maintained during aging by increased survival of adult born OLs, while the numbers of OLs in the ventral Ammon's horn may be reduced with age due to the lack of such compensatory mechanisms. These observations provide new insight into the involvement of adult oligodendrogenesis in age-related changes in the structure and function of the hippocampus.
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Affiliation(s)
- Jun Yamada
- Department of Developmental Molecular Anatomy, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
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23
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Maldonado PP, Angulo MC. Multiple Modes of Communication between Neurons and Oligodendrocyte Precursor Cells. Neuroscientist 2014; 21:266-76. [PMID: 24722526 DOI: 10.1177/1073858414530784] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The surprising discovery of bona fide synapses between neurons and oligodendrocytes precursor cells (OPCs) 15 years ago placed these progenitors as real partners of neurons in the CNS. The role of these synapses has not been established yet, but a main hypothesis is that neuron-OPC synaptic activity is a signaling pathway controlling OPC proliferation/differentiation, influencing the myelination process. However, new evidences describing non-synaptic mechanisms of communication between neurons and OPCs have revealed that neuron-OPC interactions are more complex than expected. The activation of extrasynaptic receptors by ambient neurotransmitter or local spillover and the ability of OPCs to sense neuronal activity through a potassium channel suggest that distinct modes of communication mediate different functions of OPCs in the CNS. This review discusses different mechanisms used by OPCs to interact with neurons and their potential roles during postnatal development and in brain disorders.
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Affiliation(s)
- Paloma P Maldonado
- INSERM U1128, Paris, France Université Paris Descartes, Sorbonne Paris Cité, Paris, France The Netherlands Institute for Neuroscience, the Royal Academy of Arts and Sciences, Amsterdam, the Netherlands
| | - María Cecilia Angulo
- INSERM U1128, Paris, France Université Paris Descartes, Sorbonne Paris Cité, Paris, France
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24
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Schallek J, Geng Y, Nguyen H, Williams DR. Morphology and topography of retinal pericytes in the living mouse retina using in vivo adaptive optics imaging and ex vivo characterization. Invest Ophthalmol Vis Sci 2013; 54:8237-50. [PMID: 24150762 DOI: 10.1167/iovs.13-12581] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
PURPOSE To noninvasively image retinal pericytes in the living eye and characterize NG2-positive cell topography and morphology in the adult mouse retina. METHODS Transgenic mice expressing fluorescent pericytes (NG2, DsRed) were imaged using a two-channel, adaptive optics scanning laser ophthalmoscope (AOSLO). One channel imaged vascular perfusion with near infrared light. A second channel simultaneously imaged fluorescent retinal pericytes. Mice were also imaged using wide-field ophthalmoscopy. To confirm in vivo imaging, five eyes were enucleated and imaged in flat mount with conventional fluorescent microscopy. Cell topography was quantified relative to the optic disc. RESULTS We observed strong DsRed fluorescence from NG2-positive cells. AOSLO revealed fluorescent vascular mural cells enveloping all vessels in the living retina. Cells were stellate on larger venules, and showed banded morphology on arterioles. NG2-positive cells indicative of pericytes were found on the smallest capillaries of the retinal circulation. Wide-field SLO enabled quick assessment of NG2-positive distribution, but provided insufficient resolution for cell counts. Ex vivo microscopy showed relatively even topography of NG2-positive capillary pericytes at eccentricities more than 0.3 mm from the optic disc (515 ± 94 cells/mm(2) of retinal area). CONCLUSIONS We provide the first high-resolution images of retinal pericytes in the living animal. Subcellular resolution enabled morphological identification of NG2-positive cells on capillaries showing classic features and topography of retinal pericytes. This report provides foundational basis for future studies that will track and quantify pericyte topography, morphology, and function in the living retina over time, especially in the progression of microvascular disease.
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Affiliation(s)
- Jesse Schallek
- Center for Visual Science, University of Rochester, Rochester, New York
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25
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Xu G, Wang W, Zhou M. Spatial organization of NG2 glial cells and astrocytes in rat hippocampal CA1 region. Hippocampus 2013; 24:383-95. [PMID: 24339242 DOI: 10.1002/hipo.22232] [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] [Received: 08/10/2013] [Revised: 10/31/2013] [Accepted: 11/26/2013] [Indexed: 12/12/2022]
Abstract
Similar to astrocytes, NG2 glial cells are uniformly distributed in the central nervous system (CNS). However, little is known about the interspatial relationship, nor the functional interactions between these two star-shaped glial subtypes. Confocal morphometric analysis showed that NG2 immunostained cells are spatially organized as domains in rat hippocampal CA1 region and that each NG2 glial domain occupies a spatial volume of ∼178, 364 μm(3) . The processes of NG2 glia and astrocytes overlap extensively; each NG2 glial domain interlaces with the processes deriving from 5.8 ± 0.4 neighboring astrocytes, while each astrocytic domain accommodates processes stemming from 4.5 ± 0.3 abutting NG2 glia. In CA1 stratum radiatum, the cell bodies of morphologically identified glial cells often appear to make direct somatic-somata contact, termed as doublets. We used dual patch recording and postrecording NG2/GFAP double staining to determine the glial identities of these doublets. We show that among 44 doublets, 50% were NG2 glia-astrocyte pairs, while another 38.6% and 11.4% were astrocyte-astrocyte and NG2 glia-NG2 glia pairs, respectively. In dual patch recording, neither electrical coupling nor intercellular biocytin transfer was detected in astrocyte-NG2 glia or NG2 glia-NG2 glia doublets. Altogether, although NG2 glia and astrocytes are not gap junction coupled, their cell bodies and processes are interwoven extensively. The anatomical and physiological relationships revealed in this study should facilitate future studies to understand the metabolic coupling and functional communication between NG2 glia and astrocytes.
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Affiliation(s)
- Guangjin Xu
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, People's Republic of China
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26
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Buffo A, Rossi F. Origin, lineage and function of cerebellar glia. Prog Neurobiol 2013; 109:42-63. [PMID: 23981535 DOI: 10.1016/j.pneurobio.2013.08.001] [Citation(s) in RCA: 115] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2013] [Revised: 08/06/2013] [Accepted: 08/07/2013] [Indexed: 11/16/2022]
Abstract
The glial cells of the cerebellum, and particularly astrocytes and oligodendrocytes, are characterized by a remarkable phenotypic variety, in which highly peculiar morphological features are associated with specific functional features, unique among the glial cells of the entire CNS. Here, we provide a critical report about the present knowledge of the development of cerebellar glia, including lineage relationships between cerebellar neurons, astrocytes and oligodendrocytes, the origins and the genesis of the repertoire of glial types, and the processes underlying their acquisition of mature morphological and functional traits. In parallel, we describe and discuss some fundamental roles played by specific categories of glial cells during cerebellar development. In particular, we propose that Bergmann glia exerts a crucial scaffolding activity that, together with the organizing function of Purkinje cells, is necessary to achieve the normal pattern of foliation and layering of the cerebellar cortex. Moreover, we discuss some of the functional tasks of cerebellar astrocytes and oligodendrocytes that are distinctive of cerebellar glia throughout the CNS. Notably, we report about the regulation of synaptic signalling in the molecular and granular layer mediated by Bergmann glia and parenchymal astrocytes, and the functional interaction between oligodendrocyte precursor cells and neurons. On the whole, this review provides an extensive overview of the available literature and some novel insights about the origin and differentiation of the variety of cerebellar glial cells and their function in the developing and mature cerebellum.
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Affiliation(s)
- Annalisa Buffo
- Rita Levi-Montalcini Department of Neuroscience, University of Turin, Corso Raffaello, 30, 10125 Turin, Italy; Neuroscience Institute Cavalieri Ottolenghi, Neuroscience Institute of Turin, University of Turin, Regione Gonzole 10, 10043 Orbassano, Turin, Italy.
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Neuron-NG2 cell synapses: novel functions for regulating NG2 cell proliferation and differentiation. BIOMED RESEARCH INTERNATIONAL 2013; 2013:402843. [PMID: 23984358 PMCID: PMC3747365 DOI: 10.1155/2013/402843] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/10/2013] [Accepted: 07/08/2013] [Indexed: 01/11/2023]
Abstract
NG2 cells are a population of CNS cells that are distinct from neurons, mature oligodendrocytes, astrocytes, and microglia. These cells can be identified by their NG2 proteoglycan expression. NG2 cells have a highly branched morphology, with abundant processes radiating from the cell body, and express a complex set of voltage-gated channels, AMPA/kainate, and GABA receptors. Neurons notably form classical and nonclassical synapses with NG2 cells, which have varied characteristics and functions. Neuron-NG2 cell synapses could fine-tune NG2 cell activities, including the NG2 cell cycle, differentiation, migration, and myelination, and may be a novel potential therapeutic target for NG2 cell-related diseases, such as hypoxia-ischemia injury and periventricular leukomalacia. Furthermore, neuron-NG2 cell synapses may be correlated with the plasticity of CNS in adulthood with the synaptic contacts passing onto their progenies during proliferation, and synaptic contacts decrease rapidly upon NG2 cell differentiation. In this review, we highlight the characteristics of classical and nonclassical neuron-NG2 cell synapses, the potential functions, and the fate of synaptic contacts during proliferation and differentiation, with the emphasis on the regulation of the NG2 cell cycle by neuron-NG2 cell synapses and their potential underlying mechanisms.
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Compensating for synaptic loss in Alzheimer’s disease. J Comput Neurosci 2013; 36:19-37. [DOI: 10.1007/s10827-013-0462-8] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2012] [Revised: 05/10/2013] [Accepted: 05/14/2013] [Indexed: 01/08/2023]
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Li C, Xiao L, Liu X, Yang W, Shen W, Hu C, Yang G, He C. A functional role of NMDA receptor in regulating the differentiation of oligodendrocyte precursor cells and remyelination. Glia 2013; 61:732-49. [PMID: 23440860 DOI: 10.1002/glia.22469] [Citation(s) in RCA: 99] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2012] [Accepted: 12/27/2012] [Indexed: 11/12/2022]
Abstract
Differentiation of oligodendrocyte precursor cells (OPCs) is the most important event for the myelination of central nervous system (CNS) axons during development and remyelination in demyelinating diseases, while the underlying molecular mechanisms remain largely unknown. Here we show that NMDA receptor (NMDAR) is a functional regulator of OPCs differentiation and remyelination. First, GluN1, GluN2A, and GluN2B subunits are expressed in oligodendrocyte lineage cells (OLs) in vitro and in vivo by immunostaining and Western blot analysis. Second, in a purified rat OPC culture system, NMDARs specially mediate OPCs differentiation by enhancing myelin proteins expression and the processes branching at the immature to mature oligodendrocyte transition analyzed by a serial of developmental stage-specific antigens. Moreover, pharmacological NMDAR antagonists or specific knockdown of GluN1 by RNA interference in OPCs prevents the differentiation induced by NMDA. NMDA can activate the mammalian target of rapamycin (mTOR) signal in OPCs and the pro-differentiation effect of NMDA is obstructed by the mTOR inhibitor rapamycin, suggesting NMDAR exerts its effect through mTOR-dependent mechanism. Furthermore, NMDA increases numbers of myelin segments in DRG-OPC cocultures. Finally, NMDAR specific antagonist MK801 delays remyelination in the cuprizone model examined by LFB-PAS, immunofluorescence and electron microscopy. This effect appears to result from inhibiting OPCs differentiation as more NG2(+) OPCs but less GST-π(+) mature oligodendrocytes are observed. Together, these results indicate that NMDAR plays a critical role in the regulation of OPCs differentiation in vitro and remyelination in cuprizone model which may provide potential target for the treatment of demyelination disease.
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Affiliation(s)
- Cui Li
- Institute of Neuroscience and MOE Key Laboratory of Molecular Neurobiology, Neuroscience Research Center of Changzheng Hospital, Second Military Medical University, Shanghai, 200433, China
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Ballesteros-Yáñez I, Castillo CA, Amo-Salas M, Albasanz JL, Martín M. Differential Effect of Caffeine Consumption on Diverse Brain Areas of Pregnant Rats. JOURNAL OF CAFFEINE RESEARCH 2012; 2:90-98. [PMID: 24761269 DOI: 10.1089/jcr.2012.0011] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
BACKGROUND It has previously been shown that during gestation, the mother's brain has an increase in glial fibrillary acidic protein (GFAP)-immunoreactivity (-ir) and a decrease in the mRNA level of A1 adenosine receptor. Little is known about the A2A adenosine receptor in the maternal brain, and whether caffeine consumption throughout gestational period modifies GFAP and adenosine receptor density in specific brain areas. This study was undertaken to investigate the protein density of GFAP and adenosine receptors (A1 and A2A subtypes) in different regions of pregnant rat brain and the possible effect of caffeine on these proteins. METHODS For this purpose, we examined the GFAP-, A1- and A2A-ir in the cingulate cortex (Cg2), dentate gyrus (DG), medial preoptic area (mPOA), secondary somatosensory cortex (S2), and striatum (Str) of pregnant Wistar rats (drug-free tap water or water with 1g/L diluted caffeine). RESULTS We show a consistent and highly significant reduction of GFAP-ir in caffeine-treated pregnant rats in most of the areas analyzed. Our data demonstrate that caffeine consumption induces a significant increase of A2A-ir in Str. Concerning A1 receptor, the observed changes are dependent on the region analyzed; this receptor density is increased in Cg2, DG, and mPOA and decreased in the somatosensory cortex and Str. The results were confirmed by Western blotting. CONCLUSIONS Our results suggest that chronic caffeine exposure could modify the physiolological situation of gestation by a reorganization of the neural circuits and the adenosine neuromodulator system.
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Affiliation(s)
- Inmaculada Ballesteros-Yáñez
- Department of Inorganic and Organic Chemistry and Biochemistry, Faculty of Medicine, Regional Center of Biomedical Research, University of Castilla-La Mancha , Ciudad Real, Spain . ; Department of Inorganic and Organic Chemistry and Biochemistry, Chemistry Faculty, Regional Center of Biomedical Research, University of Castilla-La Mancha , Ciudad Real, Spain
| | - Carlos Alberto Castillo
- Department of Inorganic and Organic Chemistry and Biochemistry, Chemistry Faculty, Regional Center of Biomedical Research, University of Castilla-La Mancha , Ciudad Real, Spain . ; Department of Nursing, Faculty of Nursing, Occupational and Speech Therapies, University of Castilla-La Mancha , Talavera de la Reina, Spain
| | - Mariano Amo-Salas
- Department of Mathematics, Faculty of Medicine, University of Castilla-La Mancha , Ciudad Real, Spain
| | - José Luis Albasanz
- Department of Inorganic and Organic Chemistry and Biochemistry, Faculty of Medicine, Regional Center of Biomedical Research, University of Castilla-La Mancha , Ciudad Real, Spain . ; Department of Inorganic and Organic Chemistry and Biochemistry, Chemistry Faculty, Regional Center of Biomedical Research, University of Castilla-La Mancha , Ciudad Real, Spain
| | - Mairena Martín
- Department of Inorganic and Organic Chemistry and Biochemistry, Faculty of Medicine, Regional Center of Biomedical Research, University of Castilla-La Mancha , Ciudad Real, Spain . ; Department of Inorganic and Organic Chemistry and Biochemistry, Chemistry Faculty, Regional Center of Biomedical Research, University of Castilla-La Mancha , Ciudad Real, Spain
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Mandyam CD, Koob GF. The addicted brain craves new neurons: putative role for adult-born progenitors in promoting recovery. Trends Neurosci 2012; 35:250-60. [PMID: 22265158 DOI: 10.1016/j.tins.2011.12.005] [Citation(s) in RCA: 109] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2011] [Revised: 08/30/2011] [Accepted: 12/13/2011] [Indexed: 02/08/2023]
Abstract
Addiction is a chronic relapsing disorder associated with compulsive drug taking, drug seeking and a loss of control in limiting intake, reflected in three stages of a recurrent cycle: binge/intoxication, withdrawal/negative affect, and preoccupation/anticipation ("craving"). This review discusses the role of adult-born neural and glial progenitors in drug seeking associated with the different stages of the addiction cycle. A review of the current literature suggests that the loss of newly born progenitors, particularly in hippocampal and cortical regions, plays a role in determining vulnerability to relapse in rodent models of drug addiction. The normalization of drug-impaired neurogenesis or gliogenesis may help reverse neuroplasticity during abstinence and, thus, may help reduce the vulnerability to relapse and aid recovery.
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Affiliation(s)
- Chitra D Mandyam
- Committee on the Neurobiology of Addictive Disorders, The Scripps Research Institute, La Jolla, CA, USA.
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Buttigieg J, Eftekharpour E, Karimi-Abdolrezaee S, Fehlings MG. Molecular and electrophysiological evidence for the expression of BK channels in oligodendroglial precursor cells. Eur J Neurosci 2011; 34:538-47. [DOI: 10.1111/j.1460-9568.2011.07789.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Cerebral cortex demyelination and oligodendrocyte precursor response to experimental autoimmune encephalomyelitis. Neurobiol Dis 2011; 43:678-89. [PMID: 21679768 DOI: 10.1016/j.nbd.2011.05.021] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2011] [Revised: 05/06/2011] [Accepted: 05/28/2011] [Indexed: 11/20/2022] Open
Abstract
Experimentally induced autoimmune encephalomyelitis (EAE) in mice provides an animal model that shares many features with human demyelinating diseases such as multiple sclerosis (MS). To what extent the cerebral cortex is affected by the process of demyelination and how the corollary response of the oligodendrocyte lineage is explicated are still not completely known aspects of EAE. By performing a detailed in situ analysis of expression of myelin and oligodendrocyte markers we have identified areas of subpial demyelination in the cerebral cortex of animals with conventionally induced EAE conditions. On EAE-affected cerebral cortices, the distribution and relative abundance of cells of the oligodendrocyte lineage were assessed and compared with control mouse brains. The analysis demonstrated that A2B5(+) glial restricted progenitors (GRPs) and NG2(+)/PDGFR-α(+) oligodendrocyte precursor cells (OPCs) were increased in number during "early" disease, 20 days post MOG immunization, whereas in the "late" disease, 39 days post-immunization, they were strongly diminished, and there was an accompanying reduction in NG2(+)/O4(+) pre-oligodendrocytes and GST-π mature oligodendrocytes. These results, together with the observed steady-state amount of NG2(-)/O4(+) pre-myelinating oligodendrocytes, suggested that oligodendroglial precursors attempted to compensate for the progressive loss of myelin, although these cells appeared to fail to complete the last step of their differentiation program. Our findings confirm that this chronic model of EAE reproduces the features of neocortex pathology in progressive MS and suggest that, despite the proliferative response of the oligodendroglial precursors, the failure to accomplish final differentiation may be a key contributing factor to the impaired remyelination that characterizes these demyelinating conditions.
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Richardson WD, Young KM, Tripathi RB, McKenzie I. NG2-glia as multipotent neural stem cells: fact or fantasy? Neuron 2011; 70:661-73. [PMID: 21609823 PMCID: PMC3119948 DOI: 10.1016/j.neuron.2011.05.013] [Citation(s) in RCA: 226] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/10/2011] [Indexed: 12/23/2022]
Abstract
Cycling glial precursors-"NG2-glia"-are abundant in the developing and mature central nervous system (CNS). During development, they generate oligodendrocytes. In culture, they can revert to a multipotent state, suggesting that they might have latent stem cell potential that could be harnessed to treat neurodegenerative disease. This hope has been subdued recently by a series of fate-mapping studies that cast NG2-glia as dedicated oligodendrocyte precursors in the healthy adult CNS-though rare, neuron production in the piriform cortex remains a possibility. Following CNS damage, the repertoire of NG2-glia expands to include Schwann cells and possibly astrocytes-but so far not neurons. This reaffirms the central role of NG2-glia in myelin repair. The realization that oligodendrocyte generation continues throughout normal adulthood has seeded the idea that myelin genesis might also be involved in neural plasticity. We review these developments, highlighting areas of current interest, contention, and speculation.
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Affiliation(s)
- William D Richardson
- Wolfson Institute for Biomedical Research and Research Department of Cell and Developmental Biology, University College London (UCL), UK.
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Dale N. Purinergic signaling in hypothalamic tanycytes: potential roles in chemosensing. Semin Cell Dev Biol 2011; 22:237-44. [PMID: 21396904 DOI: 10.1016/j.semcdb.2011.02.024] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2010] [Revised: 02/10/2011] [Accepted: 02/24/2011] [Indexed: 12/26/2022]
Abstract
Hypothalamic tanycytes are cells that line the walls of the 3rd ventricle. Their cell bodies contact the cerebrospinal fluid and give rise to an inwardly directed process. The more dorsally located (α1 and α2) tanycytes project to areas of the brain involved in the control of feeding and energy balance (the arcuate nucleus and ventromedial hypothalamic nucleus). Although their functions are poorly understood, they have some similarities to glial cells. Recent evidence shows that they express key molecules involved in purinergic signaling and at least some tanycytes may act as adult multipotent stem cells. Emerging evidence suggests that tanycytes signal through changes in intracellular Ca(2+) and that they can respond with large Ca(2+) signals to ATP and transmitters associated with wakefulness and the drive to feed. They are also glucosensitive and this response is dependent on release of ATP from tanycytes and the activation of P2Y1 receptors. Their ability to release ATP gives potential for their integration into the hypothalamic circuitry controlling energy balance and feeding, but many fundamental questions about their possible functions and roles remain unanswered.
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Affiliation(s)
- Nicholas Dale
- School of Life Sciences, University of Warwick, Coventry, United Kingdom.
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Maldonado PP, Vélez-Fort M, Angulo MC. Is neuronal communication with NG2 cells synaptic or extrasynaptic? J Anat 2011; 219:8-17. [PMID: 21352226 DOI: 10.1111/j.1469-7580.2011.01350.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
NG2-expressing glial cells (NG2 cells) represent a major pool of progenitors able to generate myelinating oligodendrocytes, and perhaps astrocytes and neurones, in the postnatal brain. In the last decade, it has been demonstrated that NG2 cells receive functional glutamatergic and GABAergic synapses mediating fast synaptic transmission in different brain regions. However, several controversies exist in this field. While two classes of NG2 cells have been defined by the presence or absence of Na(+) channels, action potential firing and neuronal input, other studies suggest that all NG2 cells possess Na(+) conductances and are the target of quantal neuronal release, but are unable to trigger action potential firing. Here we bring new evidence supporting the idea that the level of expression of Na(+) conductances is not a criterion to discriminate NG2 cell subpopulations in the somatosensory cortex. Surprisingly, recent reports demonstrated that NG2 cells detect quantal glutamate release from unmyelinated axons in white matter regions. Yet, it is difficult from these studies to establish whether axonal vesicular release in white matter occurs at genuine synaptic junctions or at ectopic release sites. In addition, we recently reported a new mode of extrasynaptic communication between neurones and NG2 cells that relies on pure GABA spillover and does not require GABAergic synaptic input. This review discusses the properties of quantal neuronal release onto NG2 cells and gives an extended overview of potential extrasynaptic modes of transmission, from ectopic to diffuse volume transmission, between neurones and NG2 cells in the brain.
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Parri HR, Gould TM, Crunelli V. Sensory and cortical activation of distinct glial cell subtypes in the somatosensory thalamus of young rats. Eur J Neurosci 2011; 32:29-40. [PMID: 20608967 PMCID: PMC2909395 DOI: 10.1111/j.1460-9568.2010.07281.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The rodent ventrobasal (VB) thalamus receives sensory inputs from the whiskers and projects to the cortex, from which it receives reciprocal excitatory afferents. Much is known about the properties and functional roles of these glutamatergic inputs to thalamocortical neurons in the VB, but no data are available on how these afferents can affect thalamic glial cells. In this study, we used combined electrophysiological recordings and intracellular calcium ([Ca2+]i) imaging to investigate glial cell responses to synaptic afferent stimulation. VB thalamus glial cells can be divided into two groups based on their [Ca2+]i and electrophysiological responses to sensory and corticothalamic stimulation. One group consists of astrocytes, which stain positively for S100B and preferentially load with SR101, have linear current–voltage relations and low input resistance, show no voltage-dependent [Ca2+]i responses, but express mGluR5-dependent [Ca2+]i transients following stimulation of the sensory and/or corticothalamic excitatory afferent pathways. Cells of the other glial group, by contrast, stain positively for NG2, and are characterized by high input resistance, the presence of voltage-dependent [Ca2+]i elevations and voltage-gated inward currents. There were no synaptically induced [Ca2+]i elevations in these cells under control conditions. These results show that thalamic glial cell responses to synaptic input exhibit different properties to those of thalamocortical neurons. As VB astrocytes can respond to synaptic stimulation and signal to neighbouring neurons, this glial cell organization may have functional implications for the processing of somatosensory information and modulation of behavioural state-dependent thalamocortical network activities.
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Affiliation(s)
- H Rheinallt Parri
- School of Life and Health Sciences, Aston Triangle, Aston University, Birmingham, UK.
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Abstract
Chronic unilateral hemisection (HX) of the adult rat spinal cord diminishes conduction through intact fibers in the ventrolateral funiculus (VLF) contralateral to HX. This is associated with a partial loss of myelination from fibers in the VLF (Arvanian et al., 2009). Here, we again measured conduction through the VLF using electrical stimulation while recording the resulting volley and synaptic potentials in target motoneurons. We found that intraspinal injection of chondroitinase-ABC, known to digest chondroitin sulfate proteoglycans (CSPGs), prevented the decline of axonal conduction through intact VLF fibers across from chronic T10 HX. Chondroitinase treatment was also associated with behavior suggestive of an improvement of locomotor function after chronic HX. To further study the role of CSPGs in axonal conduction, we injected three purified CSPGs, NG2 and neurocan, which increase in the vicinity of a spinal injury, and aggrecan, which decreases, into the lateral column of the uninjured cord at T10 in separate experiments. Intraspinal injection of NG2 acutely depressed axonal conduction through the injected region in a dose-dependent manner. Similar injections of saline, aggrecan, or neurocan had no significant effect. Immunofluorescence staining experiments revealed the presence of endogenous and exogenous NG2 at some nodes of Ranvier. These results identify a novel acute action of CSPGs on axonal conduction in the spinal cord and suggest that antagonism of proteoglycans reverses or prevents the decline of axonal conduction, in addition to stimulating axonal growth.
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Kitamura Y, Inden M, Minamino H, Abe M, Takata K, Taniguchi T. The 6-hydroxydopamine-induced nigrostriatal neurodegeneration produces microglia-like NG2 glial cells in the rat substantia nigra. Glia 2010; 58:1686-700. [DOI: 10.1002/glia.21040] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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Blum R, Heinrich C, Sánchez R, Lepier A, Gundelfinger ED, Berninger B, Götz M. Neuronal network formation from reprogrammed early postnatal rat cortical glial cells. ACTA ACUST UNITED AC 2010; 21:413-24. [PMID: 20562320 DOI: 10.1093/cercor/bhq107] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
In the subependymal zone and the dentate gyrus of the adult brain of rodents, neural stem cells with glial properties generate new neurons in a life-long process. The identification of glial progenitors outside the neurogenic niches, oligodendrocyte precursors in the healthy brain, and reactive astrocytes after cortical injury led to the idea of using these cells as endogenous cell source for neural repair in the cerebral cortex. Recently, our group showed that proliferating astroglia from the cerebral cortex can be reprogrammed into neurons capable of action potential firing by forced expression of neurogenic fate determinants but failed to develop synapses. Here, we describe a maturation profile of cultured reprogrammed NG2+ and glial fibrillary acidic protein+ glia cells of the postnatal rat cortex that ends with the establishment of a glutamatergic neuronal network. Within 3 weeks after viral expression of the transcription factor neurogenin 2 (Ngn2), glia-derived neurons exhibit network-driven, glutamate receptor-dependent oscillations in Ca(2+) and exhibit functional pre- and postsynaptic specialization. Interestingly, the Ngn2-instructed glutamatergic network also supports the maturation of a γ-aminobutyric acid (GABA)ergic input via GABA(A) receptors in a non-cell autonomous manner. The "proof-of-principle" results imply that a single transcription factor may be sufficient to instruct a neuronal network from a glia-like cell source.
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Affiliation(s)
- Robert Blum
- Physiological Genomics, Institute of Physiology, Ludwig-Maximilians University Munich, 80336 Munich, Germany
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Hamilton N, Vayro S, Wigley R, Butt AM. Axons and astrocytes release ATP and glutamate to evoke calcium signals in NG2-glia. Glia 2010; 58:66-79. [PMID: 19533604 DOI: 10.1002/glia.20902] [Citation(s) in RCA: 96] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
NG2-glia are an abundant population of cells in the adult CNS that make up a novel glial cell type. Here, we have examined calcium signals in NG2-glia identified by expression of the fluorescent protein DsRed under the control of the NG2 promoter in the white matter of the mouse optic nerve. We focused on mice aged postnatal day (P)12-16, after the main period of oligodendrocyte generation. Using fluo-4 and fura-2 calcium imaging in isolated intact nerves, we show that glutamate and ATP evoke Ca(2+) signals in NG2-glia in situ, acting on AMPA-type glutamate receptors and P2Y(1) and P2X(7) purine receptors; NMDA evoked a weak Ca(2+) signal in a small proportion of NG2-glia. We show that axonal action potentials and mechanical stimulation of astrocytes effect the release of glutamate and ATP to act on NG2-glia; ATP alone evokes robust Ca(2+) signals, whereas glutamate did not unless AMPA receptor desensitization was blocked with cyclothiazide. We identify the precise contacts that NG2-glia form with axons at nodes of Ranvier, and the intricate bipartite sheaths formed between the processes of NG2-glia and astrocytes. In addition, we provide evidence that NG2-glia express synaptophysin, indicating they have mechanisms for transmitting as well as receiving signals. This study places NG2-glia within a neuron-glial network, and identifies roles for glutamate and ATP in communication with astrocytes as well as axons.
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Affiliation(s)
- Nicola Hamilton
- Institute of Biology and Biomedical Sciences, School of Pharmacy and Biomedical Sciences, University of Portsmouth, Portsmouth, United Kingdom
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Leoni G, Rattray M, Butt AM. NG2 cells differentiate into astrocytes in cerebellar slices. Mol Cell Neurosci 2009; 42:208-18. [PMID: 19616628 DOI: 10.1016/j.mcn.2009.07.007] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2009] [Revised: 06/03/2009] [Accepted: 07/03/2009] [Indexed: 12/20/2022] Open
Abstract
NG2-glia are an abundant population of glial cells that have been considered by many to be oligodendrocyte progenitor cells (OPCs). However, growing evidence suggests that NG2-glia may also be capable of differentiating into astrocytes and neurons under certain conditions. Here, we have examined NG2-glia in cerebellar slices, using transgenic mice in which the astroglial marker glial specific protein (GFAP) drives expression of the reporter gene enhanced green fluorescent protein (EGFP). Immunolabelling for NG2 shows that NG2-glia and GFAP-EGFP astroglia are separate populations in most areas of the brain, although a substantial population of NG2-glia in the pons also express the GFAP-EGFP reporter. In the cerebellum, NG2-glia did not express EGFP, either at postnatal day (P)12 or P29-30. We developed an organotypic culture of P12 cerebellar slices that maintain cytoarchitectural integrity of Purkinje neurons and Bergmann glia. In these cultures, BrdU labelling indicates that the majority of NG2-glia enter the cell cycle within 2 days in vitro (DIV), suggesting that NG2-glia undergo a 'reactive' response in cerebellar cultures. After 2 DIV NG2-glia began to express the astroglial reporter EGFP and in some cases the respective GFAP protein. However, NG2-glia did not acquire phenotypic markers of neural stem cells or neurons. The results suggest that NG2-glia are not lineage restricted OPCs and are a potential source of astrocytes in the cerebellum.
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Affiliation(s)
- Giampaolo Leoni
- Institute of Biology and Biomedical Sciences, School of Pharmacy and Biomedical Sciences, University of Portsmouth, Portsmouth PO1 2DT, UK
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He Y, Cai W, Wang L, Chen P. A developmental study on the expression of PDGFαR immunoreactive cells in the brain of postnatal rats. Neurosci Res 2009; 65:272-9. [DOI: 10.1016/j.neures.2009.07.011] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2009] [Revised: 07/24/2009] [Accepted: 07/27/2009] [Indexed: 10/20/2022]
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Srikandarajah N, Martinian L, Sisodiya SM, Squier W, Blumcke I, Aronica E, Thom M. Doublecortin expression in focal cortical dysplasia in epilepsy. Epilepsia 2009; 50:2619-28. [PMID: 19583780 DOI: 10.1111/j.1528-1167.2009.02194.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
PURPOSE Doublecortin (DCX) is a microtubule-associated protein with regulatory roles in radial and tangential migration of neurons during cortical development. In normal adult cortex there is restricted expression, and DCX is widely used as a marker of neurogenesis. Imperfect corticogenesis is thought to underpin many focal cortical pathologies in epilepsy surgical series, including focal cortical dysplasia (FCD). The aim was to study DCX expression patterns in such lesions compared to normal developing and mature cortex. METHOD Cases of FCD types Ia (13) and IIb (4), pediatric hippocampal sclerosis (HS) (5), temporal lobe sclerosis (5), glioneuronal tumors (5), gray matter heterotopia (3), and control tissues (16) from a wide age range [20 gestational weeks (GW) to 85 years] were studied using immunohistochemistry to DCX. RESULTS In controls and all epilepsy cases, perinuclear labeling of small round cells (SRCs) and satellite perineuronal cells was observed in both postmortem and surgical tissues. In FCD Ia up to the age of 4 years, prominent DCX-positive (DCX(+)), immature cells were present along the junction of layers I and II, with processes extending into the molecular layer. These cell types were not a significant feature in other pathologies, which showed multipolar DCX(+) cells or labeling of dysmorphic cells throughout the cortex. DISCUSSION Persistent cellular DCX expression is confirmed in normal adult cortex. Characteristic expression patterns in layer II of FCD Ia could indicate delayed or abnormal cortical maturation rather than ongoing cytogenesis. This could be indicative of enhanced local cortical plasticity as well as a potential diagnostic feature of this type of pathology.
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Affiliation(s)
- Nisaharan Srikandarajah
- Department of Clinical and Experimental Epilepsy, Institute of Neurology, Queen Square, London, United Kingdom
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Analysis of astroglial K+ channel expression in the developing hippocampus reveals a predominant role of the Kir4.1 subunit. J Neurosci 2009; 29:7474-88. [PMID: 19515915 DOI: 10.1523/jneurosci.3790-08.2009] [Citation(s) in RCA: 178] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Astrocytes in different brain regions display variable functional properties. In the hippocampus, astrocytes predominantly express time- and voltage-independent currents, but the underlying ion channels are not well defined. This ignorance is partly attributable to abundant intercellular coupling of these cells through gap junctions, impeding quantitative analyses of intrinsic membrane properties. Moreover, distinct types of cells with astroglial properties coexist in a given brain area, a finding that confused previous analyses. In the present study, we investigated expression of inwardly rectifying (Kir) and two-pore-domain (K2P) K+ channels in astrocytes, which are thought to be instrumental in the regulation of K+ homeostasis. Freshly isolated astrocytes were used to improve space-clamp conditions and allow for quantitative assessment of functional parameters. Patch-clamp recordings were combined with immunocytochemistry, Western blot analysis, and semiquantitative transcript analysis. Comparative measurements were performed in different CA1 subregions of astrocyte-targeted transgenic mice. While confirming weak Ba2+ sensitivity in situ, our data demonstrate that in freshly isolated astrocytes, the main proportion of membrane currents is sensitive to micromolar Ba2+ concentrations. Upregulation of Kir4.1 transcripts and protein during the first 10 postnatal days was accompanied by a fourfold increase in astrocyte inward current density. Hippocampal astrocytes from Kir4.1-/- mice lacked Ba2+-sensitive currents. In addition, we report functional expression of K2P channels of the TREK subfamily (TREK1, TREK2), which mediate astroglial outward currents. Together, our findings demonstrate that Kir4.1 constitutes the pivotal K+ channel subunit and that superposition of currents through Kir4.1 and TREK channels underlies the "passive" current pattern of hippocampal astrocytes.
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Wigley R, Butt AM. Integration of NG2-glia (synantocytes) into the neuroglial network. NEURON GLIA BIOLOGY 2009; 5:21-8. [PMID: 19785922 DOI: 10.1017/s1740925x09990329] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
NG2-glia are a distinct class of CNS glial cells that are generally classed as oligodendrocyte progenitor cells. However, in the adult CNS a large fraction of NG2 cells does not appear to divide or generate oligodendrocytes. The functions of these adult NG2-glia, which we have termed synantocytes, are unknown. NG2-glia (synantocytes) form interactive domains with astrocytes and neurons. Within their domains, NG2-glia and astrocytes contact the same neurons, form multiple heterologous contacts with each other, and contact pericytes which regulate cerebral blood flow. NG2-glia receive presynaptic input from neurons and respond to neurotransmitters released at synapses. In addition, NG2-glia are intimately associated with astroglia and respond to astroglial signals, a hitherto neglected aspect of NG2-glial cell physiology. The non-overlapping domain organisation of astrocytes is believed to be important in isolating and integrating activity at the synapses and blood vessels within their domains. The domains of NG2-glia overlap with astrocytes, suggesting they could play a role in integrating non-overlapping astrocyte domains.
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Affiliation(s)
- Rebekah Wigley
- Institute for Biomedical and Biomolecular Sciences, School of Pharmacy and Biomedical Sciences, University of Portsmouth, UK
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Benesova J, Hock M, Butenko O, Prajerova I, Anderova M, Chvatal A. Quantification of astrocyte volume changes during ischemia in situ reveals two populations of astrocytes in the cortex of GFAP/EGFP mice. J Neurosci Res 2009; 87:96-111. [PMID: 18752295 DOI: 10.1002/jnr.21828] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Energy depletion during ischemia leads to disturbed ionic homeostasis and accumulation of neuroactive substances in the extracellular space, subsequently leading to volume changes in astrocytes. Confocal microscopy combined with 3D reconstruction was used to quantify ischemia-induced astrocyte volume changes in cortical slices of GFAP/EGFP transgenic mice. Twenty-minutes of oxygen-glucose deprivation (OGD) or oxygen-glucose deprivation combined with acidification (OGD(pH 6.8)) revealed the presence of two distinct astrocytic populations, the first showing a large volume increase (HR astrocytes) and the second displaying a small volume increase (LR astrocytes). In addition, changes in resting membrane potential (V(m)), measured by the patch-clamp technique, supported the existence of two astrocytic populations responding differently to ischemia. Although one group markedly depolarized during OGD or OGD(pH 6.8), only small changes in V(m) toward more negative values were observed in the second group. Conversely, acidification (ACF(pH 6.8)) led to a uniform volume decrease in all astrocytes, accompanied by only a small depolarization. Interestingly, two differently responding populations were not detected during acidification. Differences in the expression of inwardly rectifying potassium channels (Kir4.1), glial fibrillary acidic protein (GFAP), and taurine levels in cortical astrocytes were detected using immunohistochemical methods. We conclude that two distinct populations of astrocytes are present in the cortex of GFAP/EGFP mice, based on volume and V(m) changes during exposure to OGD or OGD(pH 6.8). Immunohistochemical analysis suggests that the diverse expression of Kir4.1 channels and GFAP as well as differences in the accumulation of taurine might contribute to the distinct ability of astrocytes to regulate their volume.
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Affiliation(s)
- Jana Benesova
- Laboratory of Neurobiology, Department of Cellular Neurophysiology, Institute of Experimental Medicine, Academy of Sciences of the Czech Republic, Prague, Czech Republic
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The astrocytic response in early experimental autoimmune encephalomyelitis occurs across both the grey and white matter compartments. J Neuroimmunol 2009; 208:30-9. [PMID: 19195719 DOI: 10.1016/j.jneuroim.2008.12.010] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2008] [Revised: 12/23/2008] [Accepted: 12/28/2008] [Indexed: 11/22/2022]
Abstract
An unexpectedly prominent aspect of murine experimental autoimmune encephalomyelitis is pre-onset astrocyte reactivity. Further examination of this phenomenon in the spinal cord demonstrates that grey matter, as well as white matter astrocytes, change their morphology and cell density from the earliest disease manifestation. Comparison of the two compartments reveals that, whereas white matter changes are rostro-caudally consistent, grey matter reactivity is spatially restricted and of varying amplitude between spinal cord levels. These data strongly suggest that in neuroinflammation early, cross-compartmental recruitment of astrocytes occurs, but with different expression patterns.
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Hamilton N, Hubbard PS, Butt AM. Effects of glutamate receptor activation on NG2-glia in the rat optic nerve. J Anat 2009; 214:208-18. [PMID: 19207982 PMCID: PMC2667878 DOI: 10.1111/j.1469-7580.2008.01017.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/21/2008] [Indexed: 11/29/2022] Open
Abstract
NG2-glia are a substantial population of cells in the central nervous system (CNS) that can be identified by their specific expression of the NG2 chondroitin sulphate (CSPG). NG2-glia can generate oligodendrocytes, but it is unlikely this is their only function; indeed, they may be multipotent neural stem cells. Moreover, NG2-glia are a highly reactive cell type and a major function is to help form the axon growth inhibitory glial scar in response to CNS injury. The factors that regulate these diverse behaviours of NG2-glia are not fully resolved, but NG2-glia express receptors to the neurotransmitter glutamate, which has known potent effects on other glia. Here, we have examined the actions of glutamate receptor activation on NG2-glia in the rat optic nerve, a typical CNS white matter tract that does not contain neuronal cell bodies. Glutamate induces an increase in [Ca(2+)](i) in immuno-identified NG2-glia in situ and in vitro. In addition, we examined the effects of glutamate receptor activation in vivo by focal injection of the glutamate receptor agonist kainate into the optic nerve; saline was injected in controls. Changes in glial and axonal function were determined at 7 days post injection (dpi), by immunohistochemistry and electrophysiological measurement of the compound action potential (CAP). Injection of kainate resulted in a highly localized 'injury response' in NG2-glia, marked by dense labelling for NG2 at the lesion site, as compared to astrocytes, which displayed a more extensive reactive astrogliosis. Furthermore, injection of kainate resulted in an axonal conduction block. These glial and axonal changes were not observed following injection of saline vehicle. In addition, we provide evidence that endogenous glutamate induces calcium-dependent phosphorylation of extracellular signal-regulated kinases (ERK1/2), which may provide a potential mechanism by which glutamate-mediated changes in raised intracellular calcium could regulate the observed gliosis. The results provide evidence that activation of AMPA-kainate type ionotropic glutamate receptors evoke raised calcium in NG2-glia and induces an injury response in NG2-glia.
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Affiliation(s)
- Nicola Hamilton
- Institute of Biomedical and Biomolecular Science, University of Portsmouth, UK
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Dividing glial cells maintain differentiated properties including complex morphology and functional synapses. Proc Natl Acad Sci U S A 2008; 106:328-33. [PMID: 19104058 DOI: 10.1073/pnas.0811353106] [Citation(s) in RCA: 84] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
It is generally believed that dividing cells gain complex features of differentiation only after exiting the cell cycle because cell division and differentiation are both under such tight regulation that their coexistence is deemed unlikely. As the major proliferating cell type in the mammalian CNS, NG2 glial cells (NG2 cells) account for 5-8% of the glial cell population and form synaptic contacts with neurons. Here we report that NG2 cells divide while maintaining their differentiation, including morphological features, such as the elaboration of multiple complex cellular processes and physiological features including active glutamatergic and GABAergic synaptic responses. Not only do NG2 cells continue to receive excitatory and inhibitory synaptic inputs as they undergo mitosis, a subpopulation of dividing NG2 cells can fire action potentials upon depolarization, thereby revealing that these dividing NG2 cells retain voltage-gated ion channels as well as transmitter receptors for signal processing. These findings provide a clear counterexample of the widely perceived incompatibility between cell division and differentiation.
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