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de Ceglia R, Ledonne A, Litvin DG, Lind BL, Carriero G, Latagliata EC, Bindocci E, Di Castro MA, Savtchouk I, Vitali I, Ranjak A, Congiu M, Canonica T, Wisden W, Harris K, Mameli M, Mercuri N, Telley L, Volterra A. Specialized astrocytes mediate glutamatergic gliotransmission in the CNS. Nature 2023; 622:120-129. [PMID: 37674083 PMCID: PMC10550825 DOI: 10.1038/s41586-023-06502-w] [Citation(s) in RCA: 16] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Accepted: 07/31/2023] [Indexed: 09/08/2023]
Abstract
Multimodal astrocyte-neuron communications govern brain circuitry assembly and function1. For example, through rapid glutamate release, astrocytes can control excitability, plasticity and synchronous activity2,3 of synaptic networks, while also contributing to their dysregulation in neuropsychiatric conditions4-7. For astrocytes to communicate through fast focal glutamate release, they should possess an apparatus for Ca2+-dependent exocytosis similar to neurons8-10. However, the existence of this mechanism has been questioned11-13 owing to inconsistent data14-17 and a lack of direct supporting evidence. Here we revisited the astrocyte glutamate exocytosis hypothesis by considering the emerging molecular heterogeneity of astrocytes18-21 and using molecular, bioinformatic and imaging approaches, together with cell-specific genetic tools that interfere with glutamate exocytosis in vivo. By analysing existing single-cell RNA-sequencing databases and our patch-seq data, we identified nine molecularly distinct clusters of hippocampal astrocytes, among which we found a notable subpopulation that selectively expressed synaptic-like glutamate-release machinery and localized to discrete hippocampal sites. Using GluSnFR-based glutamate imaging22 in situ and in vivo, we identified a corresponding astrocyte subgroup that responds reliably to astrocyte-selective stimulations with subsecond glutamate release events at spatially precise hotspots, which were suppressed by astrocyte-targeted deletion of vesicular glutamate transporter 1 (VGLUT1). Furthermore, deletion of this transporter or its isoform VGLUT2 revealed specific contributions of glutamatergic astrocytes in cortico-hippocampal and nigrostriatal circuits during normal behaviour and pathological processes. By uncovering this atypical subpopulation of specialized astrocytes in the adult brain, we provide insights into the complex roles of astrocytes in central nervous system (CNS) physiology and diseases, and identify a potential therapeutic target.
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Affiliation(s)
- Roberta de Ceglia
- Department of Fundamental Neuroscience, University of Lausanne, Lausanne, Switzerland
| | - Ada Ledonne
- Department of Fundamental Neuroscience, University of Lausanne, Lausanne, Switzerland
- Department of Experimental Neuroscience, IRCCS Santa Lucia Foundation, Rome, Italy
| | - David Gregory Litvin
- Department of Fundamental Neuroscience, University of Lausanne, Lausanne, Switzerland
- Wyss Center for Bio and Neuro Engineering, Campus Biotech, Geneva, Switzerland
| | - Barbara Lykke Lind
- Department of Fundamental Neuroscience, University of Lausanne, Lausanne, Switzerland
- Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Giovanni Carriero
- Department of Fundamental Neuroscience, University of Lausanne, Lausanne, Switzerland
| | | | - Erika Bindocci
- Department of Fundamental Neuroscience, University of Lausanne, Lausanne, Switzerland
| | | | - Iaroslav Savtchouk
- Department of Fundamental Neuroscience, University of Lausanne, Lausanne, Switzerland
- Department of Biomedical Sciences, Marquette University, Milwaukee, WI, USA
| | - Ilaria Vitali
- Department of Fundamental Neuroscience, University of Lausanne, Lausanne, Switzerland
| | - Anurag Ranjak
- Department of Fundamental Neuroscience, University of Lausanne, Lausanne, Switzerland
| | - Mauro Congiu
- Department of Fundamental Neuroscience, University of Lausanne, Lausanne, Switzerland
| | - Tara Canonica
- Department of Fundamental Neuroscience, University of Lausanne, Lausanne, Switzerland
| | - William Wisden
- Department of Life Sciences and UK Dementia Research Institute, Imperial College London, London, UK
| | - Kenneth Harris
- UCL Queen Square Institute of Neurology, University College London, London, UK
| | - Manuel Mameli
- Department of Fundamental Neuroscience, University of Lausanne, Lausanne, Switzerland
| | - Nicola Mercuri
- Department of Experimental Neuroscience, IRCCS Santa Lucia Foundation, Rome, Italy
- Department of Systems Medicine, University of Rome "Tor Vergata", Rome, Italy
| | - Ludovic Telley
- Department of Fundamental Neuroscience, University of Lausanne, Lausanne, Switzerland.
| | - Andrea Volterra
- Department of Fundamental Neuroscience, University of Lausanne, Lausanne, Switzerland.
- Wyss Center for Bio and Neuro Engineering, Campus Biotech, Geneva, Switzerland.
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Savtchouk I, Carriero G, Volterra A. Studying Axon-Astrocyte Functional Interactions by 3D Two-Photon Ca 2+ Imaging: A Practical Guide to Experiments and "Big Data" Analysis. Front Cell Neurosci 2018; 12:98. [PMID: 29706870 PMCID: PMC5908897 DOI: 10.3389/fncel.2018.00098] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [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: 01/24/2018] [Accepted: 03/22/2018] [Indexed: 01/06/2023] Open
Abstract
Recent advances in fast volumetric imaging have enabled rapid generation of large amounts of multi-dimensional functional data. While many computer frameworks exist for data storage and analysis of the multi-gigabyte Ca2+ imaging experiments in neurons, they are less useful for analyzing Ca2+ dynamics in astrocytes, where transients do not follow a predictable spatio-temporal distribution pattern. In this manuscript, we provide a detailed protocol and commentary for recording and analyzing three-dimensional (3D) Ca2+ transients through time in GCaMP6f-expressing astrocytes of adult brain slices in response to axonal stimulation, using our recently developed tools to perform interactive exploration, filtering, and time-correlation analysis of the transients. In addition to the protocol, we release our in-house software tools and discuss parameters pertinent to conducting axonal stimulation/response experiments across various brain regions and conditions. Our software tools are available from the Volterra Lab webpage at https://wwwfbm.unil.ch/dnf/group/glia-an-active-synaptic-partner/member/volterra-andrea-volterra in the form of software plugins for Image J (NIH)—a de facto standard in scientific image analysis. Three programs are available: MultiROI_TZ_profiler for interactive graphing of several movable ROIs simultaneously, Gaussian_Filter5D for Gaussian filtering in several dimensions, and Correlation_Calculator for computing various cross-correlation parameters on voxel collections through time.
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Affiliation(s)
- Iaroslav Savtchouk
- Department of Fundamental Neurosciences, University of Lausanne, Lausanne, Switzerland
| | - Giovanni Carriero
- Department of Fundamental Neurosciences, University of Lausanne, Lausanne, Switzerland
| | - Andrea Volterra
- Department of Fundamental Neurosciences, University of Lausanne, Lausanne, Switzerland
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Savtchouk I, Sun L, Bender CL, Yang Q, Szabó G, Gasparini S, Liu SJ. Topological Regulation of Synaptic AMPA Receptor Expression by the RNA-Binding Protein CPEB3. Cell Rep 2017; 17:86-103. [PMID: 27681423 DOI: 10.1016/j.celrep.2016.08.094] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [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: 09/10/2014] [Revised: 07/13/2016] [Accepted: 08/29/2016] [Indexed: 12/21/2022] Open
Abstract
Synaptic receptors gate the neuronal response to incoming signals, but they are not homogeneously distributed on dendrites. A spatially defined receptor distribution can preferentially amplify certain synaptic inputs, resize receptive fields of neurons, and optimize information processing within a neuronal circuit. Thus, a longstanding question is how the spatial organization of synaptic receptors is achieved. Here, we find that action potentials provide local signals that influence the distribution of synaptic AMPA receptors along dendrites in mouse cerebellar stellate cells. Graded dendritic depolarizations elevate CPEB3 protein at proximal dendrites, where we suggest that CPEB3 binds to GluA2 mRNA, suppressing GluA2 protein synthesis leading to a distance-dependent increase in synaptic GluA2 AMPARs. The activity-induced expression of CPEB3 requires increased Ca(2+) and PKC activation. Our results suggest a cell-autonomous mechanism where sustained postsynaptic firing drives graded local protein synthesis, thus directing the spatial organization of synaptic AMPARs.
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Affiliation(s)
- Iaroslav Savtchouk
- Department of Cell Biology and Anatomy, LSU Health Sciences Center, New Orleans, LA 70112, USA; Department of Biology, Penn State University, State College, PA 16802, USA
| | - Lu Sun
- Department of Cell Biology and Anatomy, LSU Health Sciences Center, New Orleans, LA 70112, USA; Department of Biology, Penn State University, State College, PA 16802, USA
| | - Crhistian L Bender
- Department of Cell Biology and Anatomy, LSU Health Sciences Center, New Orleans, LA 70112, USA
| | - Qian Yang
- Department of Cell Biology and Anatomy, LSU Health Sciences Center, New Orleans, LA 70112, USA
| | - Gábor Szabó
- Laboratory of Molecular Biology and Genetics, Institute of Experimental Medicine, 1450 Budapest, Hungary
| | - Sonia Gasparini
- Department of Cell Biology and Anatomy, LSU Health Sciences Center, New Orleans, LA 70112, USA; Neuroscience Center of Excellence, LSU Health Sciences Center, New Orleans, LA 70112, USA
| | - Siqiong June Liu
- Department of Cell Biology and Anatomy, LSU Health Sciences Center, New Orleans, LA 70112, USA; Department of Biology, Penn State University, State College, PA 16802, USA.
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Schenck S, Kunz L, Sahlender D, Pardon E, Geertsma ER, Savtchouk I, Suzuki T, Neldner Y, Štefanić S, Steyaert J, Volterra A, Dutzler R. Generation and Characterization of Anti-VGLUT Nanobodies Acting as Inhibitors of Transport. Biochemistry 2017; 56:3962-3971. [DOI: 10.1021/acs.biochem.7b00436] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Affiliation(s)
- Stephan Schenck
- Department
of Biochemistry, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Laura Kunz
- Department
of Biochemistry, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Daniela Sahlender
- Department
of Fundamental Neurosciences, University of Lausanne, Rue du Bugnon 9, 1005 Lausanne, Switzerland
| | - Els Pardon
- VIB
Center for Structural Biology, VIB, 1050 Brussels, Belgium
- Structural
Biology Brussels, Vrije Universiteit Brussel, 1050 Brussels, Belgium
| | - Eric R. Geertsma
- Department
of Biochemistry, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
- Institute
of Biochemistry, Biocenter, Goethe-University Frankfurt, Max-von-Laue-Straβe
9, 60438 Frankfurt
am Main, Germany
| | - Iaroslav Savtchouk
- Department
of Fundamental Neurosciences, University of Lausanne, Rue du Bugnon 9, 1005 Lausanne, Switzerland
| | - Toshiharu Suzuki
- Department
of Applied Chemistry, School of Engineering, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Yvonne Neldner
- Department
of Biochemistry, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Saša Štefanić
- Institute
of Parasitology, University of Zurich, Winterthurerstrasse 266a, 8057 Zurich, Switzerland
| | - Jan Steyaert
- VIB
Center for Structural Biology, VIB, 1050 Brussels, Belgium
- Structural
Biology Brussels, Vrije Universiteit Brussel, 1050 Brussels, Belgium
| | - Andrea Volterra
- Department
of Fundamental Neurosciences, University of Lausanne, Rue du Bugnon 9, 1005 Lausanne, Switzerland
| | - Raimund Dutzler
- Department
of Biochemistry, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
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Bindocci E, Savtchouk I, Liaudet N, Becker D, Carriero G, Volterra A. Three-dimensional Ca2+imaging advances understanding of astrocyte biology. Science 2017; 356:356/6339/eaai8185. [DOI: 10.1126/science.aai8185] [Citation(s) in RCA: 193] [Impact Index Per Article: 27.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2016] [Accepted: 04/12/2017] [Indexed: 11/02/2022]
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Abstract
Astrocytes participate in information processing by actively modulating synaptic properties via gliotransmitter release. Various mechanisms of astrocytic release have been reported, including release from storage organelles via exocytosis and release from the cytosol via plasma membrane ion channels and pumps. It is still not fully clear which mechanisms operate under which conditions, but some of them, being Ca2+-regulated, may be physiologically relevant. The properties of Ca2+-dependent transmitter release via exocytosis or via ion channels are different and expected to produce different extracellular transmitter concentrations over time and to have distinct functional consequences. The molecular aspects of these two release pathways are still under active investigation. Here, we discuss the existing morphological and functional evidence in support of either of them. Transgenic mouse models, specific antagonists and localization studies have provided insight into regulated exocytosis, albeit not in a systematic fashion. Even more remains to be uncovered about the details of channel-mediated release. Better functional tools and improved ultrastructural approaches are needed in order fully to define specific modalities and effects of astrocytic gliotransmitter release pathways.
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Affiliation(s)
- Daniela A Sahlender
- Department of Fundamental Neurosciences, University of Lausanne, Rue du Bugnon 9, Lausanne 1005, Switzerland
| | - Iaroslav Savtchouk
- Department of Fundamental Neurosciences, University of Lausanne, Rue du Bugnon 9, Lausanne 1005, Switzerland
| | - Andrea Volterra
- Department of Fundamental Neurosciences, University of Lausanne, Rue du Bugnon 9, Lausanne 1005, Switzerland
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Abstract
The subunit composition of synaptic AMPA receptors can undergo dynamic changes during physiological functioning and under pathological conditions. This switch in AMPA receptor phenotype involves changes in the level of GluA2 subunits that are mediated via regulated AMPA receptor trafficking, modification of local protein synthesis and altered gene transcription of GluA2 subunits. Incorporation of the GluA2 subunits into an AMPA receptor alters a number of key biophysical properties, including Ca(2+) permeability and the waveform of the synaptic current. These changes alter the ability of synaptic currents to evoke an action potential and therefore have a profound effect on the computational capability of individual neurons and thus the output of neuronal circuits.
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Affiliation(s)
- Siqiong June Liu
- Department of Cell Biology and Anatomy, LSU Health Sciences Center, New Orleans, LA 70112, USA.
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Liu Y, Savtchouk I, Acharjee S, Liu SJ. Inhibition of Ca2+-activated large-conductance K+ channel activity alters synaptic AMPA receptor phenotype in mouse cerebellar stellate cells. J Neurophysiol 2011; 106:144-52. [PMID: 21562198 DOI: 10.1152/jn.01107.2010] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Many fast-spiking inhibitory interneurons, including cerebellar stellate cells, fire brief action potentials and express α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA)-type glutamate receptors (AMPAR) that are permeable to Ca(2+) and do not contain the GluR2 subunit. In a recent study, we found that increasing action potential duration promotes GluR2 gene transcription in stellate cells. We have now tested the prediction that activation of potassium channels that control the duration of action potentials can suppress the expression of GluR2-containing AMPARs at stellate cell synapses. We find that large-conductance Ca(2+)-activated potassium (BK) channels mediate a large proportion of the depolarization-evoked noninactivating potassium current in stellate cells. Pharmacological blockade of BK channels prolonged the action potential duration in postsynaptic stellate cells and altered synaptic AMPAR subtype from GluR2-lacking to GluR2-containing Ca(2+)-impermeable AMPARs. An L-type channel blocker abolished an increase in Ca(2+) entry that was associated with spike broadening and also prevented the BK channel blocker-induced switch in AMPAR phenotype. Thus blocking BK potassium channels prolongs the action potential duration and increases the expression of GluR2-containing receptors at the synapse by enhancing Ca(2+) entry in cerebellar stellate cells.
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Affiliation(s)
- Yu Liu
- Department of Biology, Penn State University, State College, Pennsylvania, USA
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Liu Y, Formisano L, Savtchouk I, Takayasu Y, Szabó G, Zukin RS, Liu SJ. A single fear-inducing stimulus induces a transcription-dependent switch in synaptic AMPAR phenotype. Nat Neurosci 2009; 13:223-31. [PMID: 20037575 PMCID: PMC3140064 DOI: 10.1038/nn.2474] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2009] [Accepted: 11/20/2009] [Indexed: 11/09/2022]
Abstract
Changes in emotional state are known to alter neuronal excitability and can modify learning and memory formation. Such experience–dependent neuronal plasticity can be long-lasting and is thought to involve the regulation of gene transcription. Here we show that a single fear-inducing stimulus increases GluR2 mRNA abundance and promotes synaptic incorporation of GluR2-containing AMPA receptors (AMPARs) in mouse cerebellar stellate cells. The switch in synaptic AMPAR phenotype is mediated by noradrenaline and action potential prolongation. The subsequent rise in intracellular Ca2+ and activation of Ca2+-sensitive ERK /MAPK signaling trigger new GluR2 gene transcription and a switch in the synaptic AMPAR phenotype from GluR2-lacking, Ca2+-permeable, to GluR2-containing Ca2+-impermeable receptors on the order of hours. The change in glutamate receptor phenotype alters synaptic efficacy in cerebellar stellate cells. Thus, a single fear-inducing stimulus can induce a long-term change in synaptic receptor phenotype and may alter the activity of an inhibitory neural network.
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Affiliation(s)
- Yu Liu
- Department of Biology, Pennsylvania State University, University Park, Pennsylvania, USA
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Abstract
Inhibitory transmission controls the action potential firing rate and pattern of Purkinje cell activity in the cerebellum. A long-term change in inhibitory transmission is likely to have a profound effect on the activity of cerebellar neuronal circuits. However, little is known about how neuronal activity regulates synaptic transmission in GABAergic inhibitory interneurons (stellate/basket cells) in the cerebellar cortex. We have examined how glutamate released from parallel fibers (the axons of granule cells) influences postsynaptic alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA) receptors in stellate cells and modulates gamma-aminobutyric acid (GABA) release from these neurons. First, we found that burst stimulation of presynaptic parallel fibers changes the subunit composition of post-synaptic AMPA receptors from GluR2-lacking to GluR2-containing receptors. This switch reduces the Ca(2+) permeability of AMPA receptors and the excitatory postsynaptic potential amplitude and prolongs the duration of the synaptic current, producing a qualitative change in synaptic transmission. This switch in AMPA receptor phenotype can be induced by activation of extrasynaptic N-methyl-D: -aspartate (NMDA) receptors and involves PICK1 and the activation of protein kinase C. Second, activation of presynaptic NMDA receptors triggers a lasting increase in GABA release from stellate cells. These changes may provide a cellular mechanism underlying associative learning involving the cerebellum.
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Affiliation(s)
- Siqiong June Liu
- Department of Biology, Penn State University, University Park, PA 16802, USA.
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