1
|
Sancho L, Boisvert MM, Dawoodtabar T, Burgado J, Wang E, Allen NJ. Astrocyte CCN1 stabilizes neural circuits in the adult brain. bioRxiv 2024:2024.03.14.585077. [PMID: 38559139 PMCID: PMC10979986 DOI: 10.1101/2024.03.14.585077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
Neural circuits in many brain regions are refined by experience. Sensory circuits support higher plasticity at younger ages during critical periods - times of circuit refinement and maturation - and limit plasticity in adulthood for circuit stability. The mechanisms underlying these differing plasticity levels and how they serve to maintain and stabilize the properties of sensory circuits remain largely unclear. By combining a transcriptomic approach with ex vivo electrophysiology and in vivo imaging techniques, we identify that astrocytes release cellular communication network factor 1 (CCN1) to maintain synapse and circuit stability in the visual cortex. By overexpressing CCN1 in critical period astrocytes, we find that it promotes the maturation of inhibitory circuits and limits ocular dominance plasticity. Conversely, by knocking out astrocyte CCN1 in adults, binocular circuits are destabilized. These studies establish CCN1 as a novel astrocyte-secreted factor that stabilizes neuronal circuits. Moreover, they demonstrate that the composition and properties of sensory circuits require ongoing maintenance in adulthood, and that these maintenance cues are provided by astrocytes.
Collapse
|
2
|
Labarta-Bajo L, Deng J, Contreras M, Allen NJ. Protocol for the purification and transcriptomic analysis of mouse astrocytes using GFAT. STAR Protoc 2023; 4:102599. [PMID: 37742178 PMCID: PMC10522990 DOI: 10.1016/j.xpro.2023.102599] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Revised: 08/17/2023] [Accepted: 09/06/2023] [Indexed: 09/26/2023] Open
Abstract
Astrocytes are glial cells of the central nervous system that modulate neuronal function. Here, we present glyoxal-fixed astrocyte nuclei transcriptomics (GFAT), a protocol for the purification and transcriptomic analysis of astrocyte nuclei from the cortex and cerebellum of adult and aged fresh mouse brain. We describe steps for tissue dissection, glyoxal fixation, homogenization, nuclei isolation, antibody staining, fluorescence-activated cell sorting, and RT-qPCR or bulk RNA sequencing. GFAT does not require transgenic lines or viral injection and allows parallel astrocyte and neuron profiling.
Collapse
Affiliation(s)
| | - James Deng
- Salk Institute for Biological Studies, La Jolla, CA 92037, USA; Neurosciences Graduate Program, University of California, San Diego, La Jolla, CA 92093, USA
| | - Minerva Contreras
- Salk Institute for Biological Studies, La Jolla, CA 92037, USA; Neurosciences Graduate Program, University of California, San Diego, La Jolla, CA 92093, USA
| | - Nicola J Allen
- Salk Institute for Biological Studies, La Jolla, CA 92037, USA.
| |
Collapse
|
3
|
Brandebura AN, Asbell QN, Micael MKB, Allen NJ. Dysregulation of astrocyte-secreted pleiotrophin contributes to neuronal structural and functional deficits in Down Syndrome. bioRxiv 2023:2023.09.26.559633. [PMID: 37808668 PMCID: PMC10557700 DOI: 10.1101/2023.09.26.559633] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/10/2023]
Abstract
Neuronal dendrite patterning and synapse formation are tightly regulated during development to promote proper connectivity. Astrocyte-secreted proteins act as guidance and pro-synaptogenic factors during development, but little is known about how astrocytes may contribute to neurodevelopmental disorders. Here we identify down-regulation of the astrocyte-secreted molecule pleiotrophin as a major contributor to neuronal morphological alterations in the Ts65Dn mouse model of Down Syndrome. We find overlapping deficits in neuronal dendrites, spines and intracortical synapses in Ts65Dn mutant and pleiotrophin knockout mice. By targeting pleiotrophin overexpression to astrocytes in adult Ts65Dn mutant mice in vivo , we show that pleiotrophin can rescue dendrite morphology and spine density and increase excitatory synapse number. We further demonstrate functional improvements in behavior. Our findings identify pleiotrophin as a molecule that can be used in Down Syndrome to promote proper circuit connectivity, importantly at later stages of development after typical periods of circuit refinement have completed.
Collapse
|
4
|
Tan D, Konduri S, Erikci Ertunc M, Zhang P, Wang J, Chang T, Pinto AFM, Rocha A, Donaldson CJ, Vaughan JM, Ludwig RG, Willey E, Iyer M, Gray PC, Maher P, Allen NJ, Zuchero JB, Dillin A, Mori MA, Kohama SG, Siegel D, Saghatelian A. A class of anti-inflammatory lipids decrease with aging in the central nervous system. Nat Chem Biol 2023; 19:187-197. [PMID: 36266352 PMCID: PMC9898107 DOI: 10.1038/s41589-022-01165-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Accepted: 09/08/2022] [Indexed: 02/06/2023]
Abstract
Lipids contribute to the structure, development, and function of healthy brains. Dysregulated lipid metabolism is linked to aging and diseased brains. However, our understanding of lipid metabolism in aging brains remains limited. Here we examined the brain lipidome of mice across their lifespan using untargeted lipidomics. Co-expression network analysis highlighted a progressive decrease in 3-sulfogalactosyl diacylglycerols (SGDGs) and SGDG pathway members, including the potential degradation products lyso-SGDGs. SGDGs show an age-related decline specifically in the central nervous system and are associated with myelination. We also found that an SGDG dramatically suppresses LPS-induced gene expression and release of pro-inflammatory cytokines from macrophages and microglia by acting on the NF-κB pathway. The detection of SGDGs in human and macaque brains establishes their evolutionary conservation. This work enhances interest in SGDGs regarding their roles in aging and inflammatory diseases and highlights the complexity of the brain lipidome and potential biological functions in aging.
Collapse
Affiliation(s)
- Dan Tan
- Clayton Foundation Laboratories for Peptide Biology, Salk Institute for Biological Studies, La Jolla, CA, USA
| | - Srihari Konduri
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA, USA
| | - Meric Erikci Ertunc
- Clayton Foundation Laboratories for Peptide Biology, Salk Institute for Biological Studies, La Jolla, CA, USA
| | - Pan Zhang
- Department of Psychiatry, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, USA
| | - Justin Wang
- Clayton Foundation Laboratories for Peptide Biology, Salk Institute for Biological Studies, La Jolla, CA, USA
| | - Tina Chang
- Clayton Foundation Laboratories for Peptide Biology, Salk Institute for Biological Studies, La Jolla, CA, USA
| | - Antonio F M Pinto
- Clayton Foundation Laboratories for Peptide Biology, Salk Institute for Biological Studies, La Jolla, CA, USA
| | - Andrea Rocha
- Clayton Foundation Laboratories for Peptide Biology, Salk Institute for Biological Studies, La Jolla, CA, USA
| | - Cynthia J Donaldson
- Clayton Foundation Laboratories for Peptide Biology, Salk Institute for Biological Studies, La Jolla, CA, USA
| | - Joan M Vaughan
- Clayton Foundation Laboratories for Peptide Biology, Salk Institute for Biological Studies, La Jolla, CA, USA
| | - Raissa G Ludwig
- Department of Biochemistry and Tissue Biology, Institute of Biology, University of Campinas, Campinas, Brazil
| | - Elizabeth Willey
- Department of Molecular and Cellular Biology, Howard Hughes Medical Institute, The Glenn Center for Aging Research, University of California, Berkeley, Berkeley, CA, USA
| | - Manasi Iyer
- Department of Neurosurgery, Stanford University School of Medicine, Stanford, CA, USA
| | - Peter C Gray
- Clayton Foundation Laboratories for Peptide Biology, Salk Institute for Biological Studies, La Jolla, CA, USA
| | - Pamela Maher
- Cellular Neurobiology Laboratory, Salk Institute for Biological Studies, La Jolla, CA, USA
| | - Nicola J Allen
- Molecular Neurobiology Laboratory, Salk Institute for Biological Studies, La Jolla, CA, USA
| | - J Bradley Zuchero
- Department of Neurosurgery, Stanford University School of Medicine, Stanford, CA, USA
| | - Andrew Dillin
- Department of Molecular and Cellular Biology, Howard Hughes Medical Institute, The Glenn Center for Aging Research, University of California, Berkeley, Berkeley, CA, USA
| | - Marcelo A Mori
- Department of Biochemistry and Tissue Biology, Institute of Biology, University of Campinas, Campinas, Brazil
| | - Steven G Kohama
- Oregon National Primate Research Center, Oregon Health and Science University, Portland, OR, USA
| | - Dionicio Siegel
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA, USA.
| | - Alan Saghatelian
- Clayton Foundation Laboratories for Peptide Biology, Salk Institute for Biological Studies, La Jolla, CA, USA.
| |
Collapse
|
5
|
Brandebura AN, Paumier A, Onur TS, Allen NJ. Astrocyte contribution to dysfunction, risk and progression in neurodegenerative disorders. Nat Rev Neurosci 2023; 24:23-39. [PMID: 36316501 DOI: 10.1038/s41583-022-00641-1] [Citation(s) in RCA: 83] [Impact Index Per Article: 83.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/21/2022] [Indexed: 11/06/2022]
Abstract
There is increasing appreciation that non-neuronal cells contribute to the initiation, progression and pathology of diverse neurodegenerative disorders. This Review focuses on the role of astrocytes in disorders including Alzheimer disease, Parkinson disease, Huntington disease and amyotrophic lateral sclerosis. The important roles astrocytes have in supporting neuronal function in the healthy brain are considered, along with studies that have demonstrated how the physiological properties of astrocytes are altered in neurodegenerative disorders and may explain their contribution to neurodegeneration. Further, the question of whether in neurodegenerative disorders with specific genetic mutations these mutations directly impact on astrocyte function, and may suggest a driving role for astrocytes in disease initiation, is discussed. A summary of how astrocyte transcriptomic and proteomic signatures are altered during the progression of neurodegenerative disorders and may relate to functional changes is provided. Given the central role of astrocytes in neurodegenerative disorders, potential strategies to target these cells for future therapeutic avenues are discussed.
Collapse
Affiliation(s)
- Ashley N Brandebura
- Molecular Neurobiology Laboratory, Salk Institute for Biological Studies, La Jolla, CA, USA
| | - Adrien Paumier
- Molecular Neurobiology Laboratory, Salk Institute for Biological Studies, La Jolla, CA, USA
| | - Tarik S Onur
- Molecular Neurobiology Laboratory, Salk Institute for Biological Studies, La Jolla, CA, USA
| | - Nicola J Allen
- Molecular Neurobiology Laboratory, Salk Institute for Biological Studies, La Jolla, CA, USA.
| |
Collapse
|
6
|
Caldwell ALM, Sancho L, Deng J, Bosworth A, Miglietta A, Diedrich JK, Shokhirev MN, Allen NJ. Aberrant astrocyte protein secretion contributes to altered neuronal development in multiple models of neurodevelopmental disorders. Nat Neurosci 2022; 25:1163-1178. [PMID: 36042312 PMCID: PMC10395413 DOI: 10.1038/s41593-022-01150-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Accepted: 07/20/2022] [Indexed: 01/01/2023]
Abstract
Astrocytes negatively impact neuronal development in many models of neurodevelopmental disorders (NDs); however, how they do this, and if mechanisms are shared across disorders, is not known. In this study, we developed a cell culture system to ask how astrocyte protein secretion and gene expression change in three mouse models of genetic NDs (Rett, Fragile X and Down syndromes). ND astrocytes increase release of Igfbp2, a secreted inhibitor of insulin-like growth factor (IGF). IGF rescues neuronal deficits in many NDs, and we found that blocking Igfbp2 partially rescues inhibitory effects of Rett syndrome astrocytes, suggesting that increased astrocyte Igfbp2 contributes to decreased IGF signaling in NDs. We identified that increased BMP signaling is upstream of protein secretion changes, including Igfbp2, and blocking BMP signaling in Fragile X and Rett syndrome astrocytes reverses inhibitory effects on neurite outgrowth. This work provides a resource of astrocyte-secreted proteins in health and ND models and identifies novel targets for intervention in diverse NDs.
Collapse
Affiliation(s)
- Alison L M Caldwell
- Molecular Neurobiology Laboratory, Salk Institute for Biological Studies, La Jolla, CA, USA
- Neurosciences Graduate Program, University of California, San Diego, La Jolla, CA, USA
| | - Laura Sancho
- Molecular Neurobiology Laboratory, Salk Institute for Biological Studies, La Jolla, CA, USA
| | - James Deng
- Molecular Neurobiology Laboratory, Salk Institute for Biological Studies, La Jolla, CA, USA
- Neurosciences Graduate Program, University of California, San Diego, La Jolla, CA, USA
| | - Alexandra Bosworth
- Molecular Neurobiology Laboratory, Salk Institute for Biological Studies, La Jolla, CA, USA
- Neurosciences Graduate Program, University of California, San Diego, La Jolla, CA, USA
| | - Audrey Miglietta
- Molecular Neurobiology Laboratory, Salk Institute for Biological Studies, La Jolla, CA, USA
| | - Jolene K Diedrich
- Mass Spectrometry Core, Salk Institute for Biological Studies, La Jolla, CA, USA
| | - Maxim N Shokhirev
- Razavi Newman Integrative Genomics and Bioinformatics Core, Salk Institute for Biological Studies, La Jolla, CA, USA
| | - Nicola J Allen
- Molecular Neurobiology Laboratory, Salk Institute for Biological Studies, La Jolla, CA, USA.
| |
Collapse
|
7
|
Abstract
Astrocytes are non-neuronal cells that regulate synapses, neuronal circuits, and behavior. Astrocytes ensheath neuronal synapses to form the tripartite synapse where astrocytes influence synapse formation, function, and plasticity. Beyond the synapse, recent research has revealed that astrocyte influences on the nervous system extend to the modulation of neuronal circuitry and behavior. Here we review recent findings on the active role of astrocytes in behavioral modulation with a focus on in vivo studies, primarily in mice. Using tools to acutely manipulate astrocytes, such as optogenetics or chemogenetics, studies reviewed here have demonstrated a causal role for astrocytes in sleep, memory, sensorimotor behaviors, feeding, fear, anxiety, and cognitive processes like attention and behavioral flexibility. Current tools and future directions for astrocyte-specific manipulation, including methods for probing astrocyte heterogeneity, are discussed. Understanding the contribution of astrocytes to neuronal circuit activity and organismal behavior will be critical toward understanding how nervous system function gives rise to behavior.
Collapse
Affiliation(s)
- Krissy A Lyon
- Molecular Neurobiology Laboratory, The Salk Institute for Biological Studies, La Jolla, CA, United States
| | - Nicola J Allen
- Molecular Neurobiology Laboratory, The Salk Institute for Biological Studies, La Jolla, CA, United States
| |
Collapse
|
8
|
Suleymanov Y, Hines PJ, Stajic J, Osborne IS, Malo CS, Sugden AM, Allen NJ, Alderton G, Scanlon ST, Hurtley SM, Vinson V, Olingy C, Wong W, Grocholski B, Kelly PN. In Science Journals. Science 2021; 374:1335-1337. [PMID: 34882467 DOI: 10.1126/science.acx9776] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
[Figure: see text].
Collapse
|
9
|
Farhy-Tselnicker I, Boisvert MM, Liu H, Dowling C, Erikson GA, Blanco-Suarez E, Farhy C, Shokhirev MN, Ecker JR, Allen NJ. Activity-dependent modulation of synapse-regulating genes in astrocytes. eLife 2021; 10:70514. [PMID: 34494546 PMCID: PMC8497060 DOI: 10.7554/elife.70514] [Citation(s) in RCA: 48] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Accepted: 09/07/2021] [Indexed: 12/22/2022] Open
Abstract
Astrocytes regulate the formation and function of neuronal synapses via multiple signals; however, what controls regional and temporal expression of these signals during development is unknown. We determined the expression profile of astrocyte synapse-regulating genes in the developing mouse visual cortex, identifying astrocyte signals that show differential temporal and layer-enriched expression. These patterns are not intrinsic to astrocytes, but regulated by visually evoked neuronal activity, as they are absent in mice lacking glutamate release from thalamocortical terminals. Consequently, synapses remain immature. Expression of synapse-regulating genes and synaptic development is also altered when astrocyte signaling is blunted by diminishing calcium release from astrocyte stores. Single-nucleus RNA sequencing identified groups of astrocytic genes regulated by neuronal and astrocyte activity, and a cassette of genes that show layer-specific enrichment. Thus, the development of cortical circuits requires coordinated signaling between astrocytes and neurons, highlighting astrocytes as a target to manipulate in neurodevelopmental disorders.
Collapse
Affiliation(s)
- Isabella Farhy-Tselnicker
- Molecular Neurobiology Laboratory, The Salk Institute for Biological Studies, La Jolla, United States
| | - Matthew M Boisvert
- Molecular Neurobiology Laboratory, The Salk Institute for Biological Studies, La Jolla, United States
| | - Hanqing Liu
- Genomic Analysis Laboratory, The Salk Institute for Biological Studies, La Jolla, United States.,Division of Biological Sciences, University of California San Diego, La Jolla, United States
| | - Cari Dowling
- Molecular Neurobiology Laboratory, The Salk Institute for Biological Studies, La Jolla, United States
| | - Galina A Erikson
- Razavi Newman Integrative Genomics and Bioinformatics Core, The Salk Institute for Biological Studies, La Jolla, United States
| | - Elena Blanco-Suarez
- Molecular Neurobiology Laboratory, The Salk Institute for Biological Studies, La Jolla, United States
| | - Chen Farhy
- Sanford Burnham Prebys Medical Discovery Institute, La Jolla, United States
| | - Maxim N Shokhirev
- Razavi Newman Integrative Genomics and Bioinformatics Core, The Salk Institute for Biological Studies, La Jolla, United States
| | - Joseph R Ecker
- Genomic Analysis Laboratory, The Salk Institute for Biological Studies, La Jolla, United States.,Howard Hughes Medical Institute, The Salk Institute for Biological Studies, La Jolla, United States
| | - Nicola J Allen
- Molecular Neurobiology Laboratory, The Salk Institute for Biological Studies, La Jolla, United States
| |
Collapse
|
10
|
Abstract
Glial cells are non-neuronal cells in the nervous system that are crucial for proper brain development and function. Three major classes of glia in the central nervous system (CNS) include astrocytes, microglia and oligodendrocytes. These cells have dynamic morphological and functional properties and constantly surveil neural activity throughout life, sculpting synaptic plasticity. Astrocytes form part of the tripartite synapse with neurons and perform many homeostatic functions essential to proper synaptic function including clearing neurotransmitter and regulating ion balance; they can modify these properties, in addition to additional mechanisms such as gliotransmitter release, to influence short- and long-term plasticity. Microglia, the resident macrophage of the CNS, monitor synaptic activity and can eliminate synapses by phagocytosis or modify synapses by release of cytokines or neurotrophic factors. Oligodendrocytes regulate speed of action potential conduction and efficiency of information exchange through the formation of myelin, having important consequences for the plasticity of neural circuits. A deeper understanding of how glia modulate synaptic and circuit plasticity will further our understanding of the ongoing changes that take place throughout life in the dynamic environment of the CNS.
Collapse
Affiliation(s)
- Laura Sancho
- Molecular Neurobiology Laboratory, Salk Institute for Biological Studies, 10010 North Torrey Pines Rd, La Jolla, CA, 92037, USA
| | - Minerva Contreras
- Molecular Neurobiology Laboratory, Salk Institute for Biological Studies, 10010 North Torrey Pines Rd, La Jolla, CA, 92037, USA
| | - Nicola J Allen
- Molecular Neurobiology Laboratory, Salk Institute for Biological Studies, 10010 North Torrey Pines Rd, La Jolla, CA, 92037, USA.
| |
Collapse
|
11
|
Escartin C, Galea E, Lakatos A, O'Callaghan JP, Petzold GC, Serrano-Pozo A, Steinhäuser C, Volterra A, Carmignoto G, Agarwal A, Allen NJ, Araque A, Barbeito L, Barzilai A, Bergles DE, Bonvento G, Butt AM, Chen WT, Cohen-Salmon M, Cunningham C, Deneen B, De Strooper B, Díaz-Castro B, Farina C, Freeman M, Gallo V, Goldman JE, Goldman SA, Götz M, Gutiérrez A, Haydon PG, Heiland DH, Hol EM, Holt MG, Iino M, Kastanenka KV, Kettenmann H, Khakh BS, Koizumi S, Lee CJ, Liddelow SA, MacVicar BA, Magistretti P, Messing A, Mishra A, Molofsky AV, Murai KK, Norris CM, Okada S, Oliet SHR, Oliveira JF, Panatier A, Parpura V, Pekna M, Pekny M, Pellerin L, Perea G, Pérez-Nievas BG, Pfrieger FW, Poskanzer KE, Quintana FJ, Ransohoff RM, Riquelme-Perez M, Robel S, Rose CR, Rothstein JD, Rouach N, Rowitch DH, Semyanov A, Sirko S, Sontheimer H, Swanson RA, Vitorica J, Wanner IB, Wood LB, Wu J, Zheng B, Zimmer ER, Zorec R, Sofroniew MV, Verkhratsky A. Reactive astrocyte nomenclature, definitions, and future directions. Nat Neurosci 2021; 24:312-325. [PMID: 33589835 PMCID: PMC8007081 DOI: 10.1038/s41593-020-00783-4] [Citation(s) in RCA: 937] [Impact Index Per Article: 312.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Accepted: 12/16/2020] [Indexed: 12/18/2022]
Abstract
Reactive astrocytes are astrocytes undergoing morphological, molecular, and functional remodeling in response to injury, disease, or infection of the CNS. Although this remodeling was first described over a century ago, uncertainties and controversies remain regarding the contribution of reactive astrocytes to CNS diseases, repair, and aging. It is also unclear whether fixed categories of reactive astrocytes exist and, if so, how to identify them. We point out the shortcomings of binary divisions of reactive astrocytes into good-vs-bad, neurotoxic-vs-neuroprotective or A1-vs-A2. We advocate, instead, that research on reactive astrocytes include assessment of multiple molecular and functional parameters-preferably in vivo-plus multivariate statistics and determination of impact on pathological hallmarks in relevant models. These guidelines may spur the discovery of astrocyte-based biomarkers as well as astrocyte-targeting therapies that abrogate detrimental actions of reactive astrocytes, potentiate their neuro- and glioprotective actions, and restore or augment their homeostatic, modulatory, and defensive functions.
Collapse
Affiliation(s)
- Carole Escartin
- Université Paris-Saclay, CEA, CNRS, MIRCen, Laboratoire des Maladies Neurodégénératives, Fontenay-aux-Roses, France.
| | - Elena Galea
- Institut de Neurociències and Departament de Bioquímica i Biologia Molecular, Unitat de Bioquímica de Medicina, Universitat Autònoma de Barcelona, Barcelona, Spain.
- ICREA, Barcelona, Spain.
| | - András Lakatos
- John van Geest Centre for Brain Repair and Division of Stem Cell Neurobiology, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
- Wellcome Trust-MRC Cambridge Stem Cell Institute, Cambridge Biomedical Campus, Cambridge, UK
| | - James P O'Callaghan
- Health Effects Laboratory Division, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, Morgantown, West Virginia, USA
| | - Gabor C Petzold
- German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany
- Division of Vascular Neurology, Department of Neurology, University Hospital Bonn, Bonn, Germany
| | - Alberto Serrano-Pozo
- Alzheimer Research Unit, Department of Neurology, Massachusetts General Hospital, Charlestown, Massachusetts, USA
- Harvard Medical School, Boston, Massachusetts, USA
| | - Christian Steinhäuser
- Institute of Cellular Neurosciences, Medical Faculty, University of Bonn, Bonn, Germany
| | - Andrea Volterra
- Department of Fundamental Neuroscience, University of Lausanne, Lausanne, Switzerland
| | - Giorgio Carmignoto
- Neuroscience Institute, Italian National Research Council (CNR), Padua, Italy
- Department of Biomedical Sciences, University of Padua, Padua, Italy
| | - Amit Agarwal
- The Chica and Heinz Schaller Research Group, Institute for Anatomy and Cell Biology, Heidelberg University, Heidelberg, Germany
| | - Nicola J Allen
- Salk Institute for Biological Studies, Molecular Neurobiology Laboratory, La Jolla, California, USA
| | - Alfonso Araque
- Department of Neuroscience, University of Minnesota, Minneapolis, Minnesota, USA
| | | | - Ari Barzilai
- Department of Neurobiology, George S. Wise, Faculty of Life Sciences and Sagol School of Neuroscience, Tel Aviv University, Ramat Aviv Tel Aviv, Israel
| | - Dwight E Bergles
- The Solomon H. Snyder Department of Neuroscience, Kavli Neuroscience Discovery Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Gilles Bonvento
- Université Paris-Saclay, CEA, CNRS, MIRCen, Laboratoire des Maladies Neurodégénératives, Fontenay-aux-Roses, France
| | - Arthur M Butt
- School of Pharmacy and Biomedical Science, University of Portsmouth, Portsmouth, UK
| | - Wei-Ting Chen
- Center for Brain and Disease Research, VIB and University of Leuven, Leuven, Belgium
| | - Martine Cohen-Salmon
- 'Physiology and Physiopathology of the Gliovascular Unit' Research Group, Center for Interdisciplinary Research in Biology (CIRB), College de France, Unité Mixte de Recherche 7241 CNRS, Unité1050 INSERM, PSL Research University, Paris, France
| | - Colm Cunningham
- Trinity Biomedical Sciences Institute & Trinity College Institute of Neuroscience, School of Biochemistry & Immunology, Trinity College Dublin, Dublin, Republic of Ireland
| | - Benjamin Deneen
- Center for Cell and Gene Therapy, Department of Neurosurgery, Baylor College of Medicine, Houston, Texas, USA
| | - Bart De Strooper
- Center for Brain and Disease Research, VIB and University of Leuven, Leuven, Belgium
- UK Dementia Research Institute at the University College London, London, UK
| | - Blanca Díaz-Castro
- UK Dementia Research Institute at the University of Edinburgh, Centre for Discovery Brain Sciences, Edinburgh, UK
| | - Cinthia Farina
- Institute of Experimental Neurology (INSpe) and Division of Neuroscience, San Raffaele Scientific Institute, Milan, Italy
| | | | - Vittorio Gallo
- Center for Neuroscience Research, Children's National Research Institute, Children's National Hospital, Washington DC, USA
| | - James E Goldman
- Department of Pathology & Cell Biology, Columbia University, New York, New York, USA
| | - Steven A Goldman
- University of Rochester Medical Center, Rochester, New York, USA
- Center for Translational Neuromedicine, University of Copenhagen Faculty of Health and Medical Science and Rigshospitalet, Kobenhavn N, Denmark
| | - Magdalena Götz
- Physiological Genomics, Biomedical Center, Ludwig-Maximilians-Universitaet & Institute of Stem Cell Research, Helmholtz Center Munich, Munich, Germany
- Synergy, Excellence Cluster of Systems Neurology, Biomedical Center, Munich, Germany
| | - Antonia Gutiérrez
- Dpto. Biología Celular, Genética y Fisiología, Instituto de Investigación Biomédica de Málaga-IBIMA, Facultad de Ciencias, Universidad de Málaga, Málaga, Spain
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
| | - Philip G Haydon
- Department of Neuroscience, Tufts University School of Medicine, Boston, Massachusetts, USA
| | - Dieter H Heiland
- Microenvironment and Immunology Research Laboratory, Medical Center, Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Department of Neurosurgery, Medical Center, University of Freiburg, Faculty of Medicine, Freiburg, Germany
| | - Elly M Hol
- Department of Translational Neuroscience, University Medical Center Utrecht Brain Center, Utrecht University, Utrecht, The Netherlands
| | - Matthew G Holt
- Laboratory of Glia Biology, VIB-KU Leuven Center for Brain and Disease Research, Leuven, Belgium
| | - Masamitsu Iino
- Division of Cellular and Molecular Pharmacology, Nihon University School of Medicine, Tokyo, Japan
| | - Ksenia V Kastanenka
- Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts, USA
| | - Helmut Kettenmann
- Cellular Neurosciences, Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
| | - Baljit S Khakh
- Department of Physiology, David Geffen School of Medicine at UCLA, Los Angeles, California, USA
| | - Schuichi Koizumi
- Department of Neuropharmacology, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Yamanashi, Japan
| | - C Justin Lee
- Center for Cognition and Sociality, Institute for Basic Science 55, Expo-ro, Yuseong-gu, Daejeon, Korea
| | - Shane A Liddelow
- Neuroscience Institute, Department of Neuroscience and Physiology, Department of Ophthalmology, NYU School of Medicine, New York, USA
| | - Brian A MacVicar
- Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, British Columbia, Canada
| | - Pierre Magistretti
- Division of Biological and Environmental Sciences and Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
- Centre de Neurosciences Psychiatriques, University of Lausanne and CHUV, Site de Cery, Prilly-Lausanne, Lausanne, Switzerland
| | - Albee Messing
- Waisman Center and School of Veterinary Medicine, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Anusha Mishra
- Department of Neurology Jungers Center for Neurosciences Research and Knight Cardiovascular Institute, Oregon Health & Science University, Portland, Oregon, USA
| | - Anna V Molofsky
- Departments of Psychiatry/Weill Institute for Neuroscience University of California, San Francisco, California, USA
| | - Keith K Murai
- Centre for Research in Neuroscience, Department of Neurology & Neurosurgery, Brain Repair and Integrative Neuroscience Program, Research Institute of the McGill University Health Centre, Montreal, Quebec, Canada
| | - Christopher M Norris
- Sanders-Brown Center on Aging, University of Kentucky College of Medicine, Lexington, Kentucky, USA
| | - Seiji Okada
- Department of Immunobiology and Neuroscience, Medical Institute of Bioregulation, Kyushu University, Fukuoka, Japan
| | - Stéphane H R Oliet
- Université de Bordeaux, Inserm, Neurocentre Magendie, U1215, Bordeaux, France
| | - João F Oliveira
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal
- ICVS/3B's -PT Government Associate Laboratory, Braga/Guimarães, Portugal
- IPCA-EST-2Ai, Polytechnic Institute of Cávado and Ave, Applied Artificial Intelligence Laboratory, Campus of IPCA, Barcelos, Portugal
| | - Aude Panatier
- Université de Bordeaux, Inserm, Neurocentre Magendie, U1215, Bordeaux, France
| | - Vladimir Parpura
- Department of Neurobiology, The University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Marcela Pekna
- Laboratory of Regenerative Neuroimmunology, Center for Brain Repair, Department of Clinical Neuroscience, Institute of Neuroscience and Physiology, Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden
| | - Milos Pekny
- Laboratory of Astrocyte Biology and CNS Regeneration, Center for Brain Repair, Department of Clinical Neuroscience, Institute of Neuroscience and Physiology, Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden
| | - Luc Pellerin
- INSERM U1082, Université de Poitiers, Poitiers, France
| | - Gertrudis Perea
- Department of Functional and Systems Neurobiology, Cajal Institute, CSIC, Madrid, Spain
| | - Beatriz G Pérez-Nievas
- Department of Basic and Clinical Neuroscience, Maurice Wohl Clinical Neuroscience Institute, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
| | - Frank W Pfrieger
- Centre National de la Recherche Scientifique, Université de Strasbourg, Institut des Neurosciences Cellulaires et Intégratives, Strasbourg, France
| | - Kira E Poskanzer
- Department of Biochemistry & Biophysics, Kavli Institute for Fundamental Neuroscience, University of California, San Francisco, California, USA
| | - Francisco J Quintana
- Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital, Harvard Medical School. Associate Member, The Broad Institute, Boston, Massachusetts, USA
| | | | - Miriam Riquelme-Perez
- Université Paris-Saclay, CEA, CNRS, MIRCen, Laboratoire des Maladies Neurodégénératives, Fontenay-aux-Roses, France
| | - Stefanie Robel
- Fralin Biomedical Research Institute at Virginia Tech Carilion, School of Neuroscience Virginia Tech, Riverside Circle, Roanoke, Virginia, USA
| | - Christine R Rose
- Institute of Neurobiology, Heinrich Heine University, Düsseldorf, Germany
| | - Jeffrey D Rothstein
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Nathalie Rouach
- Neuroglial Interactions in Cerebral Physiology and Pathologies, Center for Interdisciplinary Research in Biology, Collège de France, CNRS UMR 7241, INSERM U1050, Labex Memolife, PSL Research University Paris, Paris, France
| | - David H Rowitch
- Wellcome Trust-MRC Cambridge Stem Cell Institute, Cambridge Biomedical Campus, Cambridge, UK
| | - Alexey Semyanov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Moscow, Russia
- Sechenov First Moscow State Medical University, Moscow, Russia
| | - Swetlana Sirko
- Physiological Genomics, Biomedical Center, LMU Munich, Munich, Germany
- Institute for Stem Cell Research, Helmholtz Zentrum Munich, Neuherberg, Germany
| | - Harald Sontheimer
- Virginia Tech School of Neuroscience and Center for Glial Biology in Health, Disease and Cancer, Virginia Tech at the Fralin Biomedical Research Institute, Roanoke, Virginia, USA
| | - Raymond A Swanson
- Dept. of Neurology, University of California San Francisco and San Francisco Veterans Affairs Health Care System, San Francisco, California, USA
| | - Javier Vitorica
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
- Dept. Bioquímica y Biología Molecular, Instituto de Biomedicina de Sevilla, Universidad de Sevilla, Hospital Virgen del Rocío/CSIC, Sevilla, Spain
| | - Ina-Beate Wanner
- Semel Institute for Neuroscience & Human Behavior, IDDRC, David Geffen School of Medicine, UCLA, Los Angeles, California, USA
| | - Levi B Wood
- George W. Woodruff School of Mechanical Engineering, Wallace H. Coulter Department of Biomedical Engineering at Georgia Tech and Emory, and Parker H. Petit Institute for Bioengineering & Bioscience, Georgia Institute of Technology, Atlanta, Georgia, USA
| | - Jiaqian Wu
- The Vivian L. Smith Department of Neurosurgery, Center for Stem Cell and Regenerative Medicine, MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, McGovern Medical School, UTHealth, University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Binhai Zheng
- Department of Neurosciences, UC San Diego School of Medicine, La Jolla; VA San Diego Research Service, San Diego, CA, USA
| | - Eduardo R Zimmer
- Department of Pharmacology, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Robert Zorec
- Laboratory of Neuroendocrinology, Molecular Cell Physiology, Institute of Pathophysiology, University of Ljubljana, Faculty of Medicine, Ljubljana, Slovenia
- Celica Biomedical, 1000, Ljubljana, Slovenia
| | - Michael V Sofroniew
- Department of Neurobiology, David Geffen School of Medicine, University of California, Los Angeles, California, USA.
| | - Alexei Verkhratsky
- Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK.
- Achúcarro Basque Center for Neuroscience, IKERBASQUE, Basque Foundation for Science, Bilbao, Spain.
| |
Collapse
|
12
|
Salas IH, Burgado J, Allen NJ. Glia: victims or villains of the aging brain? Neurobiol Dis 2020; 143:105008. [PMID: 32622920 DOI: 10.1016/j.nbd.2020.105008] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Revised: 06/14/2020] [Accepted: 06/29/2020] [Indexed: 12/11/2022] Open
Abstract
Aging is the strongest risk factor for metabolic, vascular and neurodegenerative diseases. Aging alone is associated with a gradual decline of cognitive and motor functions. Considering an increasing elderly population in the last century, understanding the cellular and molecular mechanisms contributing to brain aging is of vital importance. Recent genetic and transcriptomic findings strongly suggest that glia are the first cells changing with aging. Glial cells constitute around 50% of the total cells in the brain and play key roles regulating brain homeostasis in health and disease. Their essential functions include providing nutritional support to neurons, activation of immune responses, and regulation of synaptic transmission and plasticity. In this review we discuss how glia are altered in the aging brain and whether these alterations are protective or contribute to the age-related pathological cascade. We focus on the major morphological, transcriptional and functional changes affecting glia in a range of systems, including human, non-human primates, and rodents. We also highlight future directions for investigating the roles of glia in brain aging.
Collapse
Affiliation(s)
- Isabel H Salas
- Salk Institute for Biological Studies, Molecular Neurobiology Laboratory, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Jillybeth Burgado
- Salk Institute for Biological Studies, Molecular Neurobiology Laboratory, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Nicola J Allen
- Salk Institute for Biological Studies, Molecular Neurobiology Laboratory, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA.
| |
Collapse
|
13
|
Abstract
Are neurons solely responsible for determining behavioral output, or can other brain cells modulate behavior? In this issue of Cell, Nagai et al. demonstrate that striatal astrocytes, through GABAB receptor signaling, regulate behaviors including hyperactivity and attention by inducing new synapse formation between neurons.
Collapse
Affiliation(s)
- Nicola J Allen
- Salk Institute for Biological Studies, Molecular Neurobiology Laboratory, 10010 North Torrey Pines Rd, La Jolla, CA 92037, USA.
| |
Collapse
|
14
|
Farhy-Tselnicker I, Dowling C, Allen NJ. Astrocyte Expression of Synapse Promoting Genes is Developmentally Regulated by Neuronal and Astrocyte Activity. Biophys J 2020. [DOI: 10.1016/j.bpj.2019.11.330] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
|
15
|
Amor DJ, Stephenson SE, Mustapha M, Mensah MA, Ockeloen CW, Lee WS, Tankard RM, Phelan DG, Shinawi M, de Brouwer AP, Pfundt R, Dowling C, Toler TL, Sutton VR, Agolini E, Rinelli M, Capolino R, Martinelli D, Zampino G, Dumić M, Reardon W, Shaw-Smith C, Leventer RJ, Delatycki MB, Kleefstra T, Mundlos S, Mortier G, Bahlo M, Allen NJ, Lockhart PJ. Pathogenic Variants in GPC4 Cause Keipert Syndrome. Am J Hum Genet 2019; 104:914-924. [PMID: 30982611 DOI: 10.1016/j.ajhg.2019.02.026] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Accepted: 02/25/2019] [Indexed: 12/22/2022] Open
Abstract
Glypicans are a family of cell-surface heparan sulfate proteoglycans that regulate growth-factor signaling during development and are thought to play a role in the regulation of morphogenesis. Whole-exome sequencing of the Australian family that defined Keipert syndrome (nasodigitoacoustic syndrome) identified a hemizygous truncating variant in the gene encoding glypican 4 (GPC4). This variant, located in the final exon of GPC4, results in premature termination of the protein 51 amino acid residues prior to the stop codon, and in concomitant loss of functionally important N-linked glycosylation (Asn514) and glycosylphosphatidylinositol (GPI) anchor (Ser529) sites. We subsequently identified seven affected males from five additional kindreds with novel and predicted pathogenic variants in GPC4. Segregation analysis and X-inactivation studies in carrier females provided supportive evidence that the GPC4 variants caused the condition. Furthermore, functional studies of recombinant protein suggested that the truncated proteins p.Gln506∗ and p.Glu496∗ were less stable than the wild type. Clinical features of Keipert syndrome included a prominent forehead, a flat midface, hypertelorism, a broad nose, downturned corners of mouth, and digital abnormalities, whereas cognitive impairment and deafness were variable features. Studies of Gpc4 knockout mice showed evidence of the two primary features of Keipert syndrome: craniofacial abnormalities and digital abnormalities. Phylogenetic analysis demonstrated that GPC4 is most closely related to GPC6, which is associated with a bone dysplasia that has a phenotypic overlap with Keipert syndrome. Overall, we have shown that pathogenic variants in GPC4 cause a loss of function that results in Keipert syndrome, making GPC4 the third human glypican to be linked to a genetic syndrome.
Collapse
|
16
|
Abstract
Glypican 4 (Gpc4) is a heparan sulfate proteoglycan that regulates glutamatergic synapse formation and function in the developing brain. Gpc4 KO mice have been shown to have decreased excitatory synapse number and less synaptic GluA1 AMPA receptors, leading to decreased synaptic transmission. Further, decreased expression of Gpc4 has been linked to autism spectrum disorder (ASD). Gpc4 is expressed by both astrocytes and neurons during postnatal development, with astrocyte expression higher in juvenile stages, and neuronal expression increasing with maturation. We therefore asked if mice lacking Gpc4 display behavioral alterations that are consistent with loss of GluA1 or ASD, and if so if they occur at juvenile ages when astrocyte Gpc4 is high, or at adult ages when both astrocytes and neurons express Gpc4. We found that juvenile (P14) Gpc4 KO mice display hyperactivity in the open field, which is corrected in adult mice (3 month). Adult Gpc4 KO mice show deficient behavior in social novelty, whilst non-social behaviors such as working memory and anxiety are unaffected. Thus, Gpc4 KO mice show age-specific behavioral alterations that are consistent with altered synaptic levels of GluA1 and behaviors associated with ASD.
Collapse
Affiliation(s)
- Cari Dowling
- Molecular Neurobiology Laboratory, Salk Institute for Biological Studies, La Jolla, CA, USA
| | - Nicola J Allen
- Molecular Neurobiology Laboratory, Salk Institute for Biological Studies, La Jolla, CA, USA
| |
Collapse
|
17
|
Blanco-Suarez E, Liu TF, Kopelevich A, Allen NJ. Astrocyte-Secreted Chordin-like 1 Drives Synapse Maturation and Limits Plasticity by Increasing Synaptic GluA2 AMPA Receptors. Neuron 2018; 100:1116-1132.e13. [PMID: 30344043 DOI: 10.1016/j.neuron.2018.09.043] [Citation(s) in RCA: 110] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2018] [Revised: 08/23/2018] [Accepted: 09/25/2018] [Indexed: 02/06/2023]
Abstract
In the developing brain, immature synapses contain calcium-permeable AMPA glutamate receptors (AMPARs) that are subsequently replaced with GluA2-containing calcium-impermeable AMPARs as synapses stabilize and mature. Here, we show that this essential switch in AMPARs and neuronal synapse maturation is regulated by astrocytes. Using biochemical fractionation of astrocyte-secreted proteins and mass spectrometry, we identified that astrocyte-secreted chordin-like 1 (Chrdl1) is necessary and sufficient to induce mature GluA2-containing synapses to form. This function of Chrdl1 is independent of its role as an antagonist of bone morphogenetic proteins (BMPs). Chrdl1 expression is restricted to cortical astrocytes in vivo, peaking at the time of the AMPAR switch. Chrdl1 knockout (KO) mice display reduced synaptic GluA2 AMPARs, altered kinetics of synaptic events, and enhanced remodeling in an in vivo plasticity assay. Studies have shown that humans with mutations in Chrdl1 display enhanced learning. Thus astrocytes, via the release of Chrdl1, promote GluA2-dependent synapse maturation and thereby limit synaptic plasticity.
Collapse
Affiliation(s)
- Elena Blanco-Suarez
- The Salk Institute for Biological Studies, Molecular Neurobiology Laboratory, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Tong-Fei Liu
- The Salk Institute for Biological Studies, Molecular Neurobiology Laboratory, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Alex Kopelevich
- The Salk Institute for Biological Studies, Molecular Neurobiology Laboratory, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Nicola J Allen
- The Salk Institute for Biological Studies, Molecular Neurobiology Laboratory, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA.
| |
Collapse
|
18
|
Abstract
Glia constitute roughly half of the cells of the central nervous system (CNS) but were long-considered to be static bystanders to its formation and function. Here we provide an overview of how the diverse and dynamic functions of glial cells orchestrate essentially all aspects of nervous system formation and function. Radial glia, astrocytes, oligodendrocyte progenitor cells, oligodendrocytes, and microglia each influence nervous system development, from neuronal birth, migration, axon specification, and growth through circuit assembly and synaptogenesis. As neural circuits mature, distinct glia fulfill key roles in synaptic communication, plasticity, homeostasis, and network-level activity through dynamic monitoring and alteration of CNS structure and function. Continued elucidation of glial cell biology, and the dynamic interactions of neurons and glia, will enrich our understanding of nervous system formation, health, and function.
Collapse
Affiliation(s)
- Nicola J Allen
- Molecular Neurobiology Laboratory, Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA.
| | - David A Lyons
- Centre for Discovery Brain Sciences, University of Edinburgh, 49 Little France Crescent, Edinburgh EH16 4SB, UK.
| |
Collapse
|
19
|
Abstract
In the mammalian cerebral cortex neurons are arranged in specific layers and form connections both within the cortex and with other brain regions, thus forming a complex mesh of specialized synaptic connections comprising distinct circuits. The correct establishment of these connections during development is crucial for the proper function of the brain. Astrocytes, a major type of glial cell, are important regulators of synapse formation and function during development. While neurogenesis precedes astrogenesis in the cortex, neuronal synapses only begin to form after astrocytes have been generated, concurrent with neuronal branching and process elaboration. Here we provide a combined overview of the developmental processes of synapse and circuit formation in the rodent cortex, emphasizing the timeline of both neuronal and astrocytic development and maturation. We further discuss the role of astrocytes at the synapse, focusing on astrocyte-synapse contact and the role of synapse-related proteins in promoting formation of distinct cortical circuits.
Collapse
Affiliation(s)
- Isabella Farhy-Tselnicker
- Molecular Neurobiology Laboratory, Salk Institute for Biological Studies, 10010 North Torrey Pines Rd, La Jolla, CA, 92037, USA.
| | - Nicola J Allen
- Molecular Neurobiology Laboratory, Salk Institute for Biological Studies, 10010 North Torrey Pines Rd, La Jolla, CA, 92037, USA.
| |
Collapse
|
20
|
Zuidema JM, Kumeria T, Kim D, Kang J, Wang J, Hollett G, Zhang X, Roberts DS, Chan N, Dowling C, Blanco-Suarez E, Allen NJ, Tuszynski MH, Sailor MJ. Oriented Nanofibrous Polymer Scaffolds Containing Protein-Loaded Porous Silicon Generated by Spray Nebulization. Adv Mater 2018; 30:e1706785. [PMID: 29363828 PMCID: PMC6475500 DOI: 10.1002/adma.201706785] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Revised: 12/13/2017] [Indexed: 06/07/2023]
Abstract
Oriented composite nanofibers consisting of porous silicon nanoparticles (pSiNPs) embedded in a polycaprolactone or poly(lactide-co-glycolide) matrix are prepared by spray nebulization from chloroform solutions using an airbrush. The nanofibers can be oriented by an appropriate positioning of the airbrush nozzle, and they can direct growth of neurites from rat dorsal root ganglion neurons. When loaded with the model protein lysozyme, the pSiNPs allow the generation of nanofiber scaffolds that carry and deliver the protein under physiologic conditions (phosphate-buffered saline (PBS), at 37 °C) for up to 60 d, retaining 75% of the enzymatic activity over this time period. The mass loading of protein in the pSiNPs is 36%, and in the resulting polymer/pSiNP scaffolds it is 3.6%. The use of pSiNPs that display intrinsic photoluminescence (from the quantum-confined Si nanostructure) allows the polymer/pSiNP composites to be definitively identified and tracked by time-gated photoluminescence imaging. The remarkable ability of the pSiNPs to protect the protein payload from denaturation, both during processing and for the duration of the long-term aqueous release study, establishes a model for the generation of biodegradable nanofiber scaffolds that can load and deliver sensitive biologics.
Collapse
Affiliation(s)
| | | | - Dokyoung Kim
- Department of Anatomy and Neurobiology, College of Medicine, Kyung Hee University, 26 Kyungheedae-Ro, Dongdaemun-Gu, Seoul 02447, Republic of Korea
| | - Jinyoung Kang
- Department of Nanoengineering, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093 (USA)
| | - Joanna Wang
- Materials Science and Engineering, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA, 92093 (USA)
| | - Geoffrey Hollett
- Materials Science and Engineering, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA, 92093 (USA)
| | - Xuan Zhang
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA, 92093 (USA)
| | - David S. Roberts
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA, 92093 (USA)
| | - Nicole Chan
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA, 92093 (USA)
| | - Cari Dowling
- Molecular Neurobiology Laboratory, Salk Institute for Biological Studies, 10010 N Torrey Pines, La Jolla, CA, 92037 (USA)
| | - Elena Blanco-Suarez
- Molecular Neurobiology Laboratory, Salk Institute for Biological Studies, 10010 N Torrey Pines, La Jolla, CA, 92037 (USA)
| | - Nicola J. Allen
- Molecular Neurobiology Laboratory, Salk Institute for Biological Studies, 10010 N Torrey Pines, La Jolla, CA, 92037 (USA)
| | - Mark H. Tuszynski
- Veterans Administration Medical Center, 3350 La Jolla Village Drive, San Diego, CA, 92161 (USA), Department of Neurosciences, University of California, San Diego, 9500 Gilman, La Jolla, CA 92093 (USA)
| | - Michael J. Sailor
- Department of Chemistry and BiochemistryUniversity of California, San Diego, 9500 Gilman Drive, La Jolla, CA, 92093 (USA)
| |
Collapse
|
21
|
Abstract
Ben Barres, professor of neurobiology at Stanford University and member of the JCB editorial board for over 15 years, passed away on December 27, 2017, after a lengthy battle with pancreatic cancer. Ben left an indelible mark on the scientific community as a scientist, an advocate for equality, and an unbelievably supportive mentor. As a scientist his creative approaches led him to remarkable discoveries about the importance of glial cells in the brain, and his passion elevated these cells from the “other cells in the brain” to a significant place in the consciousness of neurobiology. As an advocate, he fought for equal treatment irrespective of gender identity, sexual orientation, race, or ethnicity, and was an inspiring supporter of junior scientists. As a mentor, he provided a creative and vibrant atmosphere for his trainees to pursue research and the never-ending support for them to flourish as independent scientists. As his former trainees, we would like to give our thoughts on Ben, and the deep impressions that he left on everyone he interacted with.
Collapse
|
22
|
Farhy-Tselnicker I, van Casteren ACM, Lee A, Chang VT, Aricescu AR, Allen NJ. Astrocyte-Secreted Glypican 4 Regulates Release of Neuronal Pentraxin 1 from Axons to Induce Functional Synapse Formation. Neuron 2017; 96:428-445.e13. [PMID: 29024665 PMCID: PMC5663462 DOI: 10.1016/j.neuron.2017.09.053] [Citation(s) in RCA: 113] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Revised: 08/31/2017] [Accepted: 09/27/2017] [Indexed: 12/15/2022]
Abstract
The generation of precise synaptic connections between developing neurons is critical to the formation of functional neural circuits. Astrocyte-secreted glypican 4 induces formation of active excitatory synapses by recruiting AMPA glutamate receptors to the postsynaptic cell surface. We now identify the molecular mechanism of how glypican 4 exerts its effect. Glypican 4 induces release of the AMPA receptor clustering factor neuronal pentraxin 1 from presynaptic terminals by signaling through presynaptic protein tyrosine phosphatase receptor δ. Pentraxin then accumulates AMPA receptors on the postsynaptic terminal forming functional synapses. Our findings reveal a signaling pathway that regulates synaptic activity during central nervous system development and demonstrates a role for astrocytes as organizers of active synaptic connections by coordinating both pre and post synaptic neurons. As mutations in glypicans are associated with neurological disorders, such as autism and schizophrenia, this signaling cascade offers new avenues to modulate synaptic function in disease. Astrocyte-secreted Gpc4 induces release of NP1 from neurons Release of NP1 is mediated through Gpc4 interaction with presynaptic RPTPδ Gpc4 or RPTPδ KO causes presynaptic NP1 retention and decreased synapse number Astrocytic release of Gpc4 provides spatial and temporal cues for synaptogenesis
Collapse
Affiliation(s)
- Isabella Farhy-Tselnicker
- Salk Institute for Biological Studies, Molecular Neurobiology Laboratory, 10010 North Torrey Pines Rd, La Jolla, CA 92037, USA
| | - Adriana C M van Casteren
- Salk Institute for Biological Studies, Molecular Neurobiology Laboratory, 10010 North Torrey Pines Rd, La Jolla, CA 92037, USA
| | - Aletheia Lee
- University of Oxford, Wellcome Trust Centre for Human Genetics, Division of Structural Biology, Roosevelt Drive, Oxford OX3 7BN, UK
| | - Veronica T Chang
- MRC Laboratory of Molecular Biology, Neurobiology Division, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge CB2 0QH, UK
| | - A Radu Aricescu
- University of Oxford, Wellcome Trust Centre for Human Genetics, Division of Structural Biology, Roosevelt Drive, Oxford OX3 7BN, UK; MRC Laboratory of Molecular Biology, Neurobiology Division, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge CB2 0QH, UK
| | - Nicola J Allen
- Salk Institute for Biological Studies, Molecular Neurobiology Laboratory, 10010 North Torrey Pines Rd, La Jolla, CA 92037, USA.
| |
Collapse
|
23
|
Abstract
In the developing brain, cortical circuits are established through a complex process of synaptogenesis, maturation, and synaptic pruning. Astrocytes carry out diverse functions during each of these stages to facilitate the formation of complex networks. Recent work has begun to demonstrate that these heterogeneous roles during excitatory synaptic development are determined by the astrocyte population, brain region, and neuron type. This review will focus on current findings which highlight cell type specific mechanisms of excitatory synaptogenesis, as well as multiple mechanisms engaged by astrocytes to facilitate synaptic maturation and pruning.
Collapse
Affiliation(s)
- Alexandra P Bosworth
- Salk Institute for Biological Studies, Molecular Neuroscience Laboratory, 10010 N Torrey Pines Rd, La Jolla, CA 92037, USA; Neurosciences Graduate Program, University of California San Diego, 9500 Gilman Dr, La Jolla, CA 92093, USA
| | - Nicola J Allen
- Salk Institute for Biological Studies, Molecular Neuroscience Laboratory, 10010 N Torrey Pines Rd, La Jolla, CA 92037, USA.
| |
Collapse
|
24
|
Abstract
Human astrocytes are increasingly appreciated as important contributors to brain function in health and disease, but techniques to study them are limited. In this issue of Neuron, Sloan and colleagues (2017) describe a new 3D culture model that generates mature human astrocytes, opening the door to future studies of their function.
Collapse
Affiliation(s)
- Nicola J Allen
- Hearst Foundation Development Chair, Molecular Neurobiology Laboratory, Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA.
| |
Collapse
|
25
|
Abstract
Astrocytes comprise half of the cells in the brain. Although astrocytes have traditionally been described as playing a supportive role for neurons, they have recently been recognized as active participants in the development and plasticity of dendritic spines and synapses. Astrocytes can eliminate dendritic spines, induce synapse formation, and regulate neurotransmission and plasticity. Dendritic spine and synapse impairments are features of many neurological disorders, including autism spectrum disorder, schizophrenia, and Alzheimer's disease. In this review we will present evidence from multiple neurological disorders demonstrating that changes in astrocyte-synapse interaction contribute to the pathologies. Genomic analysis has connected altered astrocytic gene expression with synaptic deficits in a number of neurological disorders. Alterations in astrocyte-secreted factors have been implicated in the neuronal morphology and synaptic changes seen in neurodevelopmental disorders, while alteration in astrocytic glutamate uptake is a core feature of multiple neurodegenerative disorders. This evidence clearly demonstrates that maintaining astrocyte-synapse interaction is crucial for normal central nervous system functioning. Obtaining a better understanding of the role of astrocytes at synapses in health and disease will provide a new avenue for future therapeutic targeting.
Collapse
Affiliation(s)
- Elena Blanco‐Suárez
- Salk Institute for Biological StudiesMolecular Neuroscience Laboratory10010 North Torrey Pines RdLa JollaCA92037USA
| | - Alison L. M. Caldwell
- Salk Institute for Biological StudiesMolecular Neuroscience Laboratory10010 North Torrey Pines RdLa JollaCA92037USA
| | - Nicola J. Allen
- Salk Institute for Biological StudiesMolecular Neuroscience Laboratory10010 North Torrey Pines RdLa JollaCA92037USA
| |
Collapse
|
26
|
Abstract
Astrocytes regulate multiple aspects of neuronal and synaptic function from development through to adulthood. Instead of addressing each function independently, this review provides a comprehensive overview of the different ways astrocytes modulate neuronal synaptic function throughout life, with a particular focus on recent findings in each area. It includes the emerging functions of astrocytes, such as a role in synapse formation, as well as more established roles, including the uptake and recycling of neurotransmitters. This broad approach covers the many ways astrocytes and neurons constantly interact to maintain the correct functioning of the brain. It is important to consider all of these diverse functions of astrocytes when investigating how astrocyte-neuron interactions regulate synaptic behavior to appreciate the complexity of these ongoing interactions.
Collapse
Affiliation(s)
- Nicola J Allen
- Salk Institute for Biological Studies, La Jolla, California 92037;
| |
Collapse
|
27
|
Abstract
In the brain, astrocytes dynamically interact with neuronal synapses via fine processes. New data show that, in response to synaptic plasticity stimuli, astrocyte processes rapidly move towards and enwrap active synapses, aiding in the stabilization and maintenance of active connections.
Collapse
Affiliation(s)
- Nicola J Allen
- Salk Institute for Biological Studies, Molecular Neurobiology Laboratory, 10010 North Torrey Pines Rd, La Jolla, CA 92037, USA.
| |
Collapse
|
28
|
Abstract
Astrocytes, through their close associations with synapses, can monitor and alter synaptic function, thus actively controlling synaptic transmission in the adult brain. Besides their important role at adult synapses, in the last three decades a number of critical findings have highlighted the importance of astrocytes in the establishment of synaptic connectivity in the developing brain. In this article, we will review the key findings on astrocytic control of synapse formation, function, and elimination. First, we will summarize our current structural and functional understanding of astrocytes at the synapse. Then, we will discuss the cellular and molecular mechanisms through which developing and mature astrocytes instruct the formation, maturation, and refinement of synapses. Our aim is to provide an overview of astrocytes as important players in the establishment of a functional nervous system.
Collapse
Affiliation(s)
- Won-Suk Chung
- Stanford University, School of Medicine, Department of Neurobiology, Stanford, California 94305
| | - Nicola J Allen
- Salk Institute for Biological Studies, Molecular Neurobiology Laboratory, La Jolla, California 92037
| | - Cagla Eroglu
- Duke University Medical Center, Cell Biology and Neurobiology Departments, Duke Institute for Brain Sciences, Durham, North Carolina 27710
| |
Collapse
|
29
|
Abstract
Neuronal synapse formation and maturation in the developing brain is a complex multi-step process, and it is now clear that glial cells, in particular astrocytes, are key regulators of neuronal synaptogenesis. This article reviews the progress made in the past few years in identifying molecular mechanisms that glial cells use to regulate neuronal synaptogenesis. The focus is on novel glial molecules that induce synapse formation, inhibit synapse formation, or control synaptic levels of glutamate receptors. A role for glial cells in the pathology of neurodevelopmental disorders is discussed.
Collapse
Affiliation(s)
- Nicola J Allen
- Salk Institute for Biological Studies, 10010 North Torrey Pines Rd, La Jolla, CA 92037, USA.
| |
Collapse
|
30
|
Allen NJ, Bennett ML, Foo LC, Wang GX, Chakraborty C, Smith SJ, Barres BA. Astrocyte glypicans 4 and 6 promote formation of excitatory synapses via GluA1 AMPA receptors. Nature 2012; 486:410-4. [PMID: 22722203 PMCID: PMC3383085 DOI: 10.1038/nature11059] [Citation(s) in RCA: 497] [Impact Index Per Article: 41.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2010] [Accepted: 03/16/2012] [Indexed: 12/02/2022]
Abstract
In the developing central nervous system (CNS), the control of synapse number and function is critical to the formation of neural circuits. We previously demonstrated that astrocyte-secreted factors powerfully induce the formation of functional excitatory synapses between CNS neurons1. Astrocyte-secreted thrombospondins induce structural synapses, however these synapses are post-synaptically silent2. Here we use biochemical fractionation of astrocyte conditioned media (ACM) to identify glypican 4 (Gpc4) and 6 (Gpc6) as astrocyte-secreted signals sufficient to induce functional synapses between purified retinal ganglion cell (RGC) neurons, and show that depletion of these molecules from ACM significantly reduces its ability to induce postsynaptic activity. Application of Gpc4 to purified neurons is sufficient to increase the frequency and amplitude of glutamatergic synaptic events. This is achieved by increasing the surface level and clustering, but not overall cellular protein level, of the GluA1 subunit of the AMPA glutamate receptor (AMPAR). Gpc4&6 are expressed by astrocytes in vivo in the developing CNS, with Gpc4 expression enriched in the hippocampus and Gpc6 in the cerebellum. Finally, we demonstrate that Gpc4-deficient mice have defective synapse formation, with decreased amplitude of excitatory synaptic currents in the developing hippocampus and reduced recruitment of AMPARs to synapses. These data identify glypicans as a family of novel astrocyte-derived molecules that are necessary and sufficient to promote glutamate receptor clustering and receptivity and induce the formation of post-synaptically functioning CNS synapses.
Collapse
Affiliation(s)
- Nicola J Allen
- Stanford University School of Medicine, Department of Neurobiology, 299 Campus Drive, Fairchild Science Building D231, Stanford, California 94305-5125, USA.
| | | | | | | | | | | | | |
Collapse
|
31
|
Allen NJ, Barres BA. The role of glia in the formation of functional synapses. Neurosci Res 2010. [DOI: 10.1016/j.neures.2010.07.334] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
|
32
|
Eroglu C, Allen NJ, Susman MW, O'Rourke NA, Park CY, Ozkan E, Chakraborty C, Mulinyawe SB, Annis DS, Huberman AD, Green EM, Lawler J, Dolmetsch R, Garcia KC, Smith SJ, Luo ZD, Rosenthal A, Mosher DF, Barres BA. Gabapentin receptor alpha2delta-1 is a neuronal thrombospondin receptor responsible for excitatory CNS synaptogenesis. Cell 2009; 139:380-92. [PMID: 19818485 PMCID: PMC2791798 DOI: 10.1016/j.cell.2009.09.025] [Citation(s) in RCA: 648] [Impact Index Per Article: 43.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2008] [Revised: 02/04/2009] [Accepted: 08/26/2009] [Indexed: 11/29/2022]
Abstract
Synapses are asymmetric cellular adhesions that are critical for nervous system development and function, but the mechanisms that induce their formation are not well understood. We have previously identified thrombospondin as an astrocyte-secreted protein that promotes central nervous system (CNS) synaptogenesis. Here, we identify the neuronal thrombospondin receptor involved in CNS synapse formation as alpha2delta-1, the receptor for the anti-epileptic and analgesic drug gabapentin. We show that the VWF-A domain of alpha2delta-1 interacts with the epidermal growth factor-like repeats common to all thrombospondins. alpha2delta-1 overexpression increases synaptogenesis in vitro and in vivo and is required postsynaptically for thrombospondin- and astrocyte-induced synapse formation in vitro. Gabapentin antagonizes thrombospondin binding to alpha2delta-1 and powerfully inhibits excitatory synapse formation in vitro and in vivo. These findings identify alpha2delta-1 as a receptor involved in excitatory synapse formation and suggest that gabapentin may function therapeutically by blocking new synapse formation.
Collapse
Affiliation(s)
- Cagla Eroglu
- Duke University Medical Center, Cell Biology Department, Durham, NC 27710, USA.
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
33
|
|
34
|
De Simoni A, Allen NJ, Attwell D. Charge compensation for NADPH oxidase activity in microglia in rat brain slices does not involve a proton current. Eur J Neurosci 2008; 28:1146-56. [PMID: 18783372 PMCID: PMC2628425 DOI: 10.1111/j.1460-9568.2008.06417.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2008] [Revised: 07/04/2008] [Accepted: 07/20/2008] [Indexed: 11/28/2022]
Abstract
The membrane properties of isolated cultured microglia have been extensively studied but it is important to understand their properties in situ, where they protect the brain against infection, but also contribute to neurodegenerative diseases. Microglia and macrophages attack bacteria by generating reactive oxygen species, a process which involves NADPH oxidase pumping electrons out across the cell membrane. The resulting inward current evokes a depolarization, which would inhibit the activity of the NADPH oxidase if there were no charge-compensating current which moves positive charge out across the membrane. The mechanism of this charge compensation is controversial. In neutrophils and in cultured microglia a depolarization-activated H(+) conductance has been proposed to provide charge compensation, and also to remove protons generated intracellularly by the NADPH oxidase. Alternatively, a depolarization-activated K(+) conductance has been proposed to mediate charge compensation. Here we show that in microglia, either in the resting state or when activated by the bacterial coat component lipopolysaccharide, both in acute and in cultured hippocampal slices, no significant H(+) current is detectable. This implies that the membrane properties of microglia in their normal cellular environment differ from those of cultured microglia (similarly, microglia generated a current in response to ATP but, unlike in culture, not to glutamate or GABA). Furthermore, the K(+) current (Kv1.3) that is activated by lipopolysaccharide is inactivated by depolarization, making it unsuitable for mediating charge compensation on a long time scale at positive voltages. Instead, charge compensation may be mediated by a previously undescribed non-selective cation current.
Collapse
Affiliation(s)
- Anna De Simoni
- Department of Physiology, University College London, London, UK
| | | | | |
Collapse
|
35
|
Stevens B, Allen NJ, Vazquez LE, Howell GR, Christopherson KS, Nouri N, Micheva KD, Mehalow AK, Huberman AD, Stafford B, Sher A, Litke AM, Lambris JD, Smith SJ, John SWM, Barres BA. The classical complement cascade mediates CNS synapse elimination. Cell 2008; 131:1164-78. [PMID: 18083105 DOI: 10.1016/j.cell.2007.10.036] [Citation(s) in RCA: 2120] [Impact Index Per Article: 132.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2007] [Revised: 08/15/2007] [Accepted: 10/15/2007] [Indexed: 12/16/2022]
Abstract
During development, the formation of mature neural circuits requires the selective elimination of inappropriate synaptic connections. Here we show that C1q, the initiating protein in the classical complement cascade, is expressed by postnatal neurons in response to immature astrocytes and is localized to synapses throughout the postnatal CNS and retina. Mice deficient in complement protein C1q or the downstream complement protein C3 exhibit large sustained defects in CNS synapse elimination, as shown by the failure of anatomical refinement of retinogeniculate connections and the retention of excess retinal innervation by lateral geniculate neurons. Neuronal C1q is normally downregulated in the adult CNS; however, in a mouse model of glaucoma, C1q becomes upregulated and synaptically relocalized in the adult retina early in the disease. These findings support a model in which unwanted synapses are tagged by complement for elimination and suggest that complement-mediated synapse elimination may become aberrantly reactivated in neurodegenerative disease.
Collapse
Affiliation(s)
- Beth Stevens
- Department of Neurobiology, Stanford University School of Medicine, Stanford, CA 94305, USA.
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
36
|
Abstract
Glial cells are now emerging from the shadows cast by their more excitable CNS counterparts. Within the developing nervous system, astrocytes and Schwann cells actively help to promote synapse formation and function, and have even been implicated in synapse elimination. In the adult brain, astrocytes respond to synaptic activity by releasing transmitters that modulate synaptic activity. Thus, glia are active participants in brain function. Many questions remain about the identity of glial-neuronal signals and their significance.
Collapse
Affiliation(s)
- Nicola J Allen
- Department of Neurobiology, Stanford University School of Medicine, Stanford, CA 94305, USA.
| | | |
Collapse
|
37
|
Abstract
During brain anoxia or ischemia, a decrease in the level of ATP leads to a sudden decrease in transmembrane ion gradients [anoxic depolarization (AD)]. This releases glutamate by reversing the operation of glutamate transporters, which triggers neuronal death. By whole-cell clamping CA1 pyramidal cells, we investigated the energy stores that delay the occurrence of the AD in hippocampal slices when O2 and glucose are removed. With glycolytic and mitochondrial ATP production blocked in P12 slices, the AD occurred in approximately 7 min at 33 degrees C, reflecting the time needed for metabolic activity to consume the existing ATP and phosphocreatine, and for subsequent ion gradient decrease. Allowing glycolysis fueled by glycogen, in the absence of glucose, delayed the AD by 5.5 min, whereas superfused glucose prevented the AD for >1 h. With glycolysis blocked, the latency to the AD was 6.5 min longer when mitochondria were allowed to function, demonstrating that metabolites downstream of glycolysis (pyruvate, citric acid cycle intermediates, and amino acid oxidation) provide a significant energy store for oxidative phosphorylation. With glycolysis blocked but mitochondria functioning, superfusing lactate did not significantly delay the AD, showing that ATP production from lactate is much less than that from endogenous metabolites. These data demonstrate a preferential role for glycolysis in preventing the AD. They also define a hierarchy of pool sizes for hippocampal energy stores and suggest that brain ATP production from glial lactate may not be significant in conditions of energy deprivation.
Collapse
Affiliation(s)
- Nicola J Allen
- Department of Physiology, University College London, London WC1E 6BT, United Kingdom
| | | | | |
Collapse
|
38
|
Abstract
An early consequence of brain energy deprivation is an increase in the frequency of spontaneous inhibitory and excitatory postsynaptic currents (sIPSCs and sEPSCs), which may disrupt neural information processing. This increase in spontaneous transmitter release has been reported to occur in calcium-free solution and has been attributed either to calcium release from internal stores or to a direct effect of hypoxia on the transmitter release mechanism. Here we investigate the mechanism of the increase in sIPSC frequency that occurs in area CA1 of rat hippocampus during simulated ischaemia, by making patch-clamp recordings from CA1 pyramidal neurones. When recording in whole-cell mode, exposure to ischaemic solution increased the sIPSC frequency 30-fold (to 49 Hz) after 5 min, and doubled the sIPSC amplitude. Ischaemic sIPSCs were action potential independent, vesicular in origin and, contrary to the results of earlier studies which did not buffer extracellular calcium to a low level, dependent on extracellular calcium. The properties of the ischaemic sIPSCs were not affected by depleting intracellular stores of calcium or by blocking the neuronal GABA transporter GAT-1. Recording from neurones using gramicidin-perforated patch-clamping showed a 10-fold smaller, more transient increase in sIPSC frequency during ischaemia, with no change of sIPSC amplitude, suggesting that whole-cell clamp recording increases the ischaemia-induced sIPSC rate and amplitude by controlling the intracellular milieu.
Collapse
Affiliation(s)
- Nicola J Allen
- Department of Physiology, University College London, Gower Street, London WC1E 6BT, UK
| | | |
Collapse
|
39
|
Allen NJ, Káradóttir R, Attwell D. Reversal or reduction of glutamate and GABA transport in CNS pathology and therapy. Pflugers Arch 2004; 449:132-42. [PMID: 15338308 DOI: 10.1007/s00424-004-1318-x] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2004] [Accepted: 05/20/2004] [Indexed: 10/26/2022]
Abstract
A dysfunction of amino acid neurotransmitter transporters occurs in a number of central nervous system disorders, including stroke, epilepsy, cerebral palsy and amyotrophic lateral sclerosis. This dysfunction can comprise a reversal of transport direction, leading to the release of neurotransmitter into the extracellular space, or an alteration in transporter expression level. This review analyses the role of glutamate and GABA transporters in the pathogenesis and therapy of a number of acute and chronic neurological disorders.
Collapse
Affiliation(s)
- Nicola J Allen
- Department of Physiology, University College London, Gower Street, London, WC1E 6BT, UK
| | | | | |
Collapse
|
40
|
Allen NJ, Rossi DJ, Attwell D. Sequential release of GABA by exocytosis and reversed uptake leads to neuronal swelling in simulated ischemia of hippocampal slices. J Neurosci 2004; 24:3837-49. [PMID: 15084665 PMCID: PMC6729351 DOI: 10.1523/jneurosci.5539-03.2004] [Citation(s) in RCA: 96] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
GABA release during cerebral energy deprivation (produced by anoxia or ischemia) has been suggested either to be neuroprotective, because GABA will hyperpolarize neurons and reduce release of excitotoxic glutamate, or to be neurotoxic, because activation of GABA(A) receptors facilitates Cl- entry into neurons and consequent cell swelling. We have used the GABA(A) receptors of hippocampal area CA1 pyramidal cells to sense the rise of [GABA](o) occurring in simulated ischemia. Ischemia evoked, after several minutes, a large depolarization to approximately -20 mV. Before this "anoxic depolarization," there was an increase in GABA release by exocytosis (spontaneous IPSCs). After the anoxic depolarization, there was a much larger, sustained release of GABA that was not affected by blocking action potentials, vesicular release, or the glial GABA transporter GAT-3 but was inhibited by blocking the neuronal GABA transporter GAT-1. Blocking GABA(A) receptors resulted in a more positive anoxic depolarization but decreased cell swelling at the time of the anoxic depolarization. The influence of GABA(A) receptors diminished in prolonged ischemia because glutamate release evoked by the anoxic depolarization inhibited GABA(A) receptor function by causing calcium entry through NMDA receptors. These data show that ischemia releases GABA initially by exocytosis and then by reversal of GAT-1 transporters and that the resulting Cl- influx through GABA(A) receptor channels causes potentially neurotoxic cell swelling.
Collapse
Affiliation(s)
- Nicola J Allen
- Department of Physiology, University College London, London WC1E 6BT, United Kingdom
| | | | | |
Collapse
|
41
|
Abstract
Acid-sensing ion channels (ASICs), activated by a decrease of extracellular pH, are found in neurons throughout the nervous system. They have an amino acid sequence similar to that of ion channels activated by membrane stretch, and have been implicated in touch sensation. Here we characterize the pH-dependent activation of ASICs in cerebellar Purkinje cells and investigate how they are modulated by factors released in ischaemia. Lowering the external pH from 7.4 activated an inward current at -66 mV, carried largely by Na+ ions, which was half-maximal for a step to pH 6.4 and was blocked by amiloride and gadolinium. The H+-gated current desensitized within a few seconds, but approximately 30 % of cells showed a sustained inward current (11 % of the peak current) in response to the maintained presence of pH 6 solution. The peak H+-evoked current was potentiated by membrane stretch (which occurs in ischaemia when [K+]o rises) and by arachidonic acid (which is released when [Ca2+]i rises in ischaemia). Arachidonic acid increased to 77 % the fraction of cells showing a sustained current evoked by acid pH. The ASIC currents were also potentiated by lactate (which is released when metabolism becomes anaerobic in ischaemia) and by FMRFamide (which may mimic the action of related mammalian RFamide transmitters). These data reinforce suggestions of a mechanosensory aspect to ASIC channel function, and show that the activation of ASICs reflects the integration of multiple signals which are present during ischaemia.
Collapse
Affiliation(s)
- Nicola J Allen
- Department of Physiology, University College London, Gower Street, London WC1E 6BT, UK
| | | |
Collapse
|
42
|
Keelan J, Allen NJ, Antcliffe D, Pal S, Duchen MR. Quantitative imaging of glutathione in hippocampal neurons and glia in culture using monochlorobimane. J Neurosci Res 2001; 66:873-84. [PMID: 11746414 DOI: 10.1002/jnr.10085] [Citation(s) in RCA: 108] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Glutathione (GSH) is a major antioxidant system in the mammalian central nervous system (CNS). Abnormalities of GSH metabolism have been associated with many disorders of the CNS, including Parkinson's, Alzheimer's, and Huntingdon's diseases and ischaemic/reperfusion injury. Investigation of GSH levels in the CNS generally relies on biochemical assays from cultures enriched for different cell types. Because glia influence neuronal metabolism, we have studied cultures in which neurons and glia are cocultured. This approach demands fluorescence imaging to differentiate between the different cell types in the culture, permitted by the use of monochlorobimane (MCB), which reacts with GSH to produce a fluorescent product. We have defined the conditions required to ensure steady-state MCB loading and show the specificity of MCB for GSH through a reaction catalysed by glutathione-S-transferase (GST). [GSH] was consistently higher in glia than in neurons, and [GSH] in both cell types decreased with time in culture. Inhibition of GSH synthesis by buthionine sulfoximine (BSO) caused a greater proportional depletion of GSH in glia than in neurons. The depletion of GSH induced by BSO was significantly greater in cells cultured for >10 days. Furthermore, release of GSH from glia and its breakdown by the ectoenzyme gamma-glutamyltranspeptidase (gammaGT) maintains [GSH] in neurons. In older cultures, inhibition of gammaGT by acivicin caused significant depletion of neuronal GSH. After inhibition of GSH synthesis by BSO, inhibition of the glia-neuron trafficking pathway by acivicin caused widespread neuronal death. Such neurotoxicity was independent of the endogenous glutamate and nitric oxide synthase, suggesting that it is not due to secondary excitotoxicity.
Collapse
Affiliation(s)
- J Keelan
- Department of Physiology, University College London, Gower Street, London WC1N 6BT, United Kingdom
| | | | | | | | | |
Collapse
|
43
|
|
44
|
Abstract
Relations between occupational commitment (OC) and several person- and work-related variables were examined meta-analytically (76 samples; across analyses, Ns ranged 746-15,774). Major findings are as follows. First, OC was positively related to job-focused constructs such as job involvement and satisfaction, suggesting that attitudes toward the job itself may be a central concern in committing to one's occupation. Second, consistent with previous work, OC and organizational commitment were positively related. This relation was found to be moderated by the compatibility of the profession and the employing organization. Third, OC was positively related to job performance and had an indirect effect on organizational turnover intention through occupational turnover intention. This latter effect suggests that understanding of organizational turnover can be enhanced by incorporating occupation-related variables into turnover models.
Collapse
Affiliation(s)
- K Lee
- Department of Psychology, University of Western Ontario, London, Canada.
| | | | | |
Collapse
|
45
|
Allan NJ, Allen NJ. Goal attainment and life satisfaction: variables under study. Perspectives 1998; 22:9-13. [PMID: 9732659] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
|
46
|
Abstract
Within the past few years, several studies have used the Affective, Continuance, and Normative Commitment Scales (Allen & Meyer, 1990; Meyer & Allen, 1984, 1991) to assess organizational commitment. The purpose of this paper is to review and evaluate the body of evidence relevant to the construct validity of these measures. Although some empirical questions remain at issue, the overall results strongly support the continued use of the scales in substantive research.
Collapse
Affiliation(s)
- NJ Allen
- The University of Western Ontario
| | | |
Collapse
|
47
|
Abe K, Abt I, Ahn CJ, Akagi T, Allen NJ, Ash WW, Aston D, Bacchetta N, Baird KG, Baltay C, Band HR, Barakat MB, Baranko G, Bardon O, Barklow T, Bazarko AO, Ben-David R, Benvenuti AC, Bienz T, Bilei GM, Bisello D, Blaylock G, Bogart JR, Bolton T, Bower GR, Brau JE, Breidenbach M, Bugg WM, Burke D, Burnett TH, Burrows PN, Busza W, Calcaterra A, Caldwell DO, Calloway D, Camanzi B, Carpinelli M, Cassell R, Castaldi R, Castro A, Cavalli-Sforza M, Church E, Cohn HO, Coller JA, Cook V, Cotton R, Cowan RF, Coyne DG, D'Oliveira A, Damerell CJ, Dell'Orso R, Dima M, Du PY, Dubois R, Eisenstein BI, Elia R, Falciai D, Fan C, Fero MJ, Frey R, Furuno K, Gillman T. Test of the flavor independence of strong interactions. Phys Rev D Part Fields 1996; 53:R2271-R2275. [PMID: 10020282 DOI: 10.1103/physrevd.53.r2271] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
|
48
|
Abe K, Abt I, Ahn CJ, Akagi T, Allen NJ, Ash WW, Aston D, Baird KG, Baltay C, Band HR, Barakat MB, Baranko G, Bardon O, Barklow T, Bazarko AO, Ben-David R, Benvenuti AC, Bienz T, Bilei GM, Bisello D, Blaylock G, Bogart JR, Bolton T, Bower GR, Brau JE, Breidenbach M, Bugg WM, Burke D, Burnett TH, Burrows PN, Busza W, Calcaterra A, Caldwell DO, Calloway D, Camanzi B, Carpinelli M, Cassell R, Castaldi R, Castro A, Cavalli-Sforza M, Church E, Cohn HO, Coller JA, Cook V, Cotton R, Cowan RF, Coyne DG, D'Oliveira A, Damerell CJ, Daoudi M, Dell'Orso R, Dima M, Du PY, Dubois R, Eisenstein BI, Elia R, Etzion E, Falciai D, Fero MJ, Frey R, Furuno K, Gillman T. Measurements of Rb with impact parameters and displaced vertices. Phys Rev D Part Fields 1996; 53:1023-1038. [PMID: 10020096 DOI: 10.1103/physrevd.53.1023] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
|
49
|
Abe K, Abt I, Ahn CJ, Akagi T, Allen NJ, Ash WW, Aston D, Baird KG, Baltay C, Band HR, Barakat MB, Baranko G, Bardon O, Barklow T, Bazarko AO, Ben-David R, Benvenuti AC, Bienz T, Bilei GM, Bisello D, Blaylock G, Bogart JR, Bolton T, Bower GR, Brau JE, Breidenbach M, Bugg WM, Burke D, Burnett TH, Burrows PN, Busza W, Calcaterra A, Caldwell DO, Calloway D, Camanzi B, Carpinelli M, Cassell R, Castaldi R, Castro A, Cavalli-Sforza M, Church E, Cohn HO, Coller JA, Cook V, Cotton R, Cowan RF, Coyne DG, D'Oliveira A, Damerell CJ, Daoudi M, Dell'Orso R, Dima M, Du PY, Dubois R, Eisenstein BI, Elia R, Falciai D, Fero MJ, Frey R, Furuno K, Gillman T, Gladding G. First Measurement of the T-Odd Correlation between the Z0 Spin and the Three-Jet Plane Orientation in Polarized Z0 Decays into Three Jets. Phys Rev Lett 1995; 75:4173-4177. [PMID: 10059838 DOI: 10.1103/physrevlett.75.4173] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
|
50
|
Abe K, Abt I, Ahn CJ, Akagi T, Allen NJ, Ash WW, Aston D, Baird KG, Baltay C, Band HR, Barakat MB, Baranko G, Bardon O, Barklow T, Bazarko AO, Ben-David R, Benvenuti AC, Bilei GM, Bisello D, Blaylock G, Bogart JR, Bolton T, Bower GR, Brau JE, Breidenbach M, Bugg WM, Burke D, Burnett TH, Burrows PN, Busza W, Calcaterra A, Caldwell DO, Calloway D, Camanzi B, Carpinelli M, Cassell R, Castaldi R, Castro A, Cavalli-Sforza M, Church E, Cohn HO, Coller JA, Cook V, Cotton R, Cowan RF, Coyne DG, D'Oliveira A, Damerell CJ, Daoudi M, Dell'Orso R, Dima M, Du PY, Dubois R, Eisenstein BI, Elia R, Falciai D, Fan C, Fero MJ, Frey R, Furuno K, Gillman T, Gladding G. Measurement of the average B hadron lifetime in Z0 decays using reconstructed vertices. Phys Rev Lett 1995; 75:3624-3628. [PMID: 10059686 DOI: 10.1103/physrevlett.75.3624] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
|