Journal ArticleDOI
Control of synapse number by glia.
TLDR
It is shown that few synapses form in the absence of glial cells and that the fewsynapses that do form are functionally immature, and that CNS synapse number can be profoundly regulated by nonneuronal signals.Abstract:
Although astrocytes constitute nearly half of the cells in our brain, their function is a long-standing neurobiological mystery. Here we show by quantal analyses, FM1-43 imaging, immunostaining, and electron microscopy that few synapses form in the absence of glial cells and that the few synapses that do form are functionally immature. Astrocytes increase the number of mature, functional synapses on central nervous system (CNS) neurons by sevenfold and are required for synaptic maintenance in vitro. We also show that most synapses are generated concurrently with the development of glia in vivo. These data demonstrate a previously unknown function for glia in inducing and stabilizing CNS synapses, show that CNS synapse number can be profoundly regulated by nonneuronal signals, and raise the possibility that glia may actively participate in synaptic plasticity.read more
Citations
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Journal ArticleDOI
Astrocytes: biology and pathology
TL;DR: Astrocyte functions in healthy CNS, mechanisms and functions of reactive astrogliosis and glial scar formation, and ways in which reactive astrocytes may cause or contribute to specific CNS disorders and lesions are reviewed.
Journal ArticleDOI
The classical complement cascade mediates CNS synapse elimination.
Beth Stevens,Nicola J. Allen,Luis E. Vazquez,Gareth R. Howell,Karen S. Christopherson,Navid Nouri,Kristina D. Micheva,Adrienne K. Mehalow,Andrew D. Huberman,Benjamin K. Stafford,Alexander Sher,Alan Litke,John D. Lambris,Stephen J. Smith,Simon W. M. John,Ben A. Barres +15 more
TL;DR: It is shown 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, supporting a model in which unwanted synapses are tagged by complement for elimination and suggesting that complement-mediated synapse elimination may become aberrantly reactivated in neurodegenerative disease.
Journal ArticleDOI
Equal numbers of neuronal and nonneuronal cells make the human brain an isometrically scaled‐up primate brain
Frederico A. C. Azevedo,Ludmila R.B. Carvalho,Lea T. Grinberg,José Marcelo Farfel,Renata E.L. Ferretti,Renata Elaine Paraizo Leite,Wilson Jacob Filho,Roberto Lent,Suzana Herculano-Houzel +8 more
TL;DR: The findings challenge the common view that humans stand out from other primates in their brain composition and indicate that, with regard to numbers of neuronal and nonneuronal cells, the human brain is an isometrically scaled‐up primate brain.
Journal ArticleDOI
Astrocytes, from brain glue to communication elements: the revolution continues.
Andrea Volterra,Jacopo Meldolesi +1 more
TL;DR: The recent recognition that astrocytes are organized in separate territories and possess active properties — notably a competence for the regulated release of 'gliotransmitters', including glutamate — has enabled us to develop an understanding of previously unknown functions for astroCytes.
Journal ArticleDOI
Purification and Characterization of Progenitor and Mature Human Astrocytes Reveals Transcriptional and Functional Differences with Mouse.
Ye Zhang,Steven A. Sloan,Laura E. Clarke,Christine Caneda,Colton A. Plaza,Paul D. Blumenthal,Hannes Vogel,Gary K. Steinberg,Michael S. B. Edwards,Gordon Li,John A. Duncan,Samuel H. Cheshier,Lawrence M. Shuer,Edward F. Chang,Gerald A. Grant,Melanie Hayden Gephart,Ben A. Barres +16 more
TL;DR: The development of an immunopanning method to acutely purify astrocytes from fetal, juvenile, and adult human brains and to maintain these cells in serum-free cultures is reported, finding that human astroCytes have abilities similar to those of murine astroicytes in promoting neuronal survival, inducing functional synapse formation, and engulfing synaptosomes.
References
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Journal ArticleDOI
Tripartite synapses : Glia, the unacknowledged partner
TL;DR: It is suggested that perisynaptic Schwann cells and synaptically associated astrocytes should be viewed as integral modulatory elements of tripartite synapses.
Journal ArticleDOI
Synaptotagmin I: a major Ca2+ sensor for transmitter release at a central synapse.
Martin Geppert,Yukiko Goda,Robert E. Hammer,Cai Li,Thomas W. Rosahl,Charles F. Stevens,Thomas C. Südhof +6 more
TL;DR: It is proposed that synaptotagmin I is the major low affinity Ca2+ sensor mediating Ca2-regulation of synchronous neurotransmitter release in hippocampal neurons and not essential for asynchronous or Ca(2+)-independent release.
Journal ArticleDOI
Quantitative Ultrastructural Analysis of Hippocampal Excitatory Synapses
TL;DR: The distribution of active zone areas can account for the distribution of synaptic release probabilities and that each active zone constitutes a release site as identified in the standard quantal theory attributable to Katz (1969).
Journal ArticleDOI
Three-Dimensional Relationships between Hippocampal Synapses and Astrocytes
Rachel Ventura,Kristen M. Harris +1 more
TL;DR: In this paper, the authors investigated structural relationships between hippocampal astrocytes and synapses in stratum radiatum of hippocampal area CA1 in the mature rat in vivo and in slices.
Journal ArticleDOI
Synaptic efficacy enhanced by glial cells in vitro.
Frank W. Pfrieger,Ben A. Barres +1 more
TL;DR: Developing neurons in culture form inefficient synapses that require glial signals to become fully functional, and the role of glial cells in synapse formation and function was studied in cultures of purified neurons from the rat central nervous system.