1
|
Wrackmeyer U, Kaldrack J, Jüttner R, Pannasch U, Gimber N, Freiberg F, Purfürst B, Kainmueller D, Schmitz D, Haucke V, Rathjen FG, Gotthardt M. The cell adhesion protein CAR is a negative regulator of synaptic transmission. Sci Rep 2019; 9:6768. [PMID: 31043663 PMCID: PMC6494904 DOI: 10.1038/s41598-019-43150-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [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: 09/26/2018] [Accepted: 04/17/2019] [Indexed: 11/09/2022] Open
Abstract
The Coxsackievirus and adenovirus receptor (CAR) is essential for normal electrical conductance in the heart, but its role in the postnatal brain is largely unknown. Using brain specific CAR knockout mice (KO), we discovered an unexpected role of CAR in neuronal communication. This includes increased basic synaptic transmission at hippocampal Schaffer collaterals, resistance to fatigue, and enhanced long-term potentiation. Spontaneous neurotransmitter release and speed of endocytosis are increased in KOs, accompanied by increased expression of the exocytosis associated calcium sensor synaptotagmin 2. Using proximity proteomics and binding studies, we link CAR to the exocytosis machinery as it associates with syntenin and synaptobrevin/VAMP2 at the synapse. Increased synaptic function does not cause adverse effects in KO mice, as behavior and learning are unaffected. Thus, unlike the connexin-dependent suppression of atrioventricular conduction in the cardiac knockout, communication in the CAR deficient brain is improved, suggesting a role for CAR in presynaptic processes.
Collapse
Affiliation(s)
- Uta Wrackmeyer
- Neuromuscular and Cardiovascular Cell Biology, Max Delbrück Center for Molecular Medicine, 13125, Berlin, Germany
| | - Joanna Kaldrack
- Neuromuscular and Cardiovascular Cell Biology, Max Delbrück Center for Molecular Medicine, 13125, Berlin, Germany
| | - René Jüttner
- Neuromuscular and Cardiovascular Cell Biology, Max Delbrück Center for Molecular Medicine, 13125, Berlin, Germany.,Developmental Neurobiology, Max Delbrück Center for Molecular Medicine, 13125, Berlin, Germany
| | - Ulrike Pannasch
- Neuroscience Research Center, Cluster of Excellence NeuroCure, Charité, 10117, Berlin, Germany
| | - Niclas Gimber
- Department of Molecular Pharmacology and Cell Biology, Leibniz Forschungsinstitut für Molekulare Pharmakologie (FMP), 13125, Berlin, Germany
| | - Fabian Freiberg
- Neuromuscular and Cardiovascular Cell Biology, Max Delbrück Center for Molecular Medicine, 13125, Berlin, Germany
| | - Bettina Purfürst
- Core Facility Electron Microscopy, Max Delbrück Center for Molecular Medicine, 13125, Berlin, Germany
| | - Dagmar Kainmueller
- Biomedical Image Analysis, Max Delbrück Center for Molecular Medicine and Berlin Institute of Health, 13125, Berlin, Germany
| | - Dietmar Schmitz
- Neuroscience Research Center, Cluster of Excellence NeuroCure, Charité, 10117, Berlin, Germany
| | - Volker Haucke
- Department of Molecular Pharmacology and Cell Biology, Leibniz Forschungsinstitut für Molekulare Pharmakologie (FMP), 13125, Berlin, Germany
| | - Fritz G Rathjen
- Developmental Neurobiology, Max Delbrück Center for Molecular Medicine, 13125, Berlin, Germany
| | - Michael Gotthardt
- Neuromuscular and Cardiovascular Cell Biology, Max Delbrück Center for Molecular Medicine, 13125, Berlin, Germany.
| |
Collapse
|
2
|
Pannasch U, Dossi E, Ezan P, Rouach N. Astroglial Cx30 sustains neuronal population bursts independently of gap-junction mediated biochemical coupling. Glia 2019; 67:1104-1112. [PMID: 30794327 PMCID: PMC6519011 DOI: 10.1002/glia.23591] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [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: 07/27/2018] [Revised: 12/21/2018] [Accepted: 12/28/2018] [Indexed: 11/06/2022]
Abstract
Astroglial networks mediated by gap junction channels contribute to neurotransmission and promote neuronal coordination. Connexin 30, one of the two main astroglial gap junction forming protein, alters at the behavioral level the reactivity of mice to novel environment and at the synaptic level excitatory transmission. However, the role and function of Cx30 at the neuronal network level remain unclear. We thus investigated whether Cx30 regulates neuronal population bursts and associated convulsive behavior. We found in vivo that Cx30 is upregulated by kainate-induced seizures and that it regulates in turn the severity of associated behavioral seizures. Using electrophysiology ex vivo, we report that Cx30 regulates aberrant network activity via control of astroglial glutamate clearance independently of gap-junction mediated biochemical coupling. Altogether, our results indicate that astroglial Cx30 is an important player in orchestrating neuronal network activity.
Collapse
Affiliation(s)
- Ulrike Pannasch
- Neuroglial Interactions in Cerebral Physiopathology, Center for Interdisciplinary Research in Biology, Collège de France, Centre National de la Recherche Scientifique UMR 7241, Institut National de la Santé et de la Recherche Médicale U1050, Labex Memolife, PSL Research University, Paris, France
| | - Elena Dossi
- Neuroglial Interactions in Cerebral Physiopathology, Center for Interdisciplinary Research in Biology, Collège de France, Centre National de la Recherche Scientifique UMR 7241, Institut National de la Santé et de la Recherche Médicale U1050, Labex Memolife, PSL Research University, Paris, France
| | - Pascal Ezan
- Neuroglial Interactions in Cerebral Physiopathology, Center for Interdisciplinary Research in Biology, Collège de France, Centre National de la Recherche Scientifique UMR 7241, Institut National de la Santé et de la Recherche Médicale U1050, Labex Memolife, PSL Research University, Paris, France
| | - Nathalie Rouach
- Neuroglial Interactions in Cerebral Physiopathology, Center for Interdisciplinary Research in Biology, Collège de France, Centre National de la Recherche Scientifique UMR 7241, Institut National de la Santé et de la Recherche Médicale U1050, Labex Memolife, PSL Research University, Paris, France
| |
Collapse
|
3
|
Ghézali G, Calvo CF, Pillet LE, Llense F, Ezan P, Pannasch U, Bemelmans AP, Etienne Manneville S, Rouach N. Connexin 30 controls astroglial polarization during postnatal brain development. Development 2018; 145:145/4/dev155275. [PMID: 29475972 PMCID: PMC5869003 DOI: 10.1242/dev.155275] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [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: 05/23/2017] [Accepted: 01/21/2018] [Indexed: 12/26/2022]
Abstract
Astrocytes undergo intense morphological maturation during development, changing from individual sparsely branched cells to polarized and tremendously ramified cells. Connexin 30, an astroglial gap-junction channel-forming protein expressed postnatally, regulates in situ the extension and ramification of astroglial processes. However, the involvement of connexin 30 in astroglial polarization, which is known to control cell morphology, remains unexplored. We found that connexin 30, independently of gap-junction-mediated intercellular biochemical coupling, alters the orientation of astrocyte protrusion, centrosome and Golgi apparatus during polarized migration in an in vitro wound-healing assay. Connexin 30 sets the orientation of astroglial motile protrusions via modulation of the laminin/β1 integrin/Cdc42 polarity pathway. Connexin 30 indeed reduces laminin levels, inhibits the redistribution of the β1-integrin extracellular matrix receptors, and inhibits the recruitment and activation of the small Rho GTPase Cdc42 at the leading edge of migrating astrocytes. In vivo, connexin 30, the expression of which is developmentally regulated, also contributes to the establishment of hippocampal astrocyte polarity during postnatal maturation. This study thus reveals that connexin 30 controls astroglial polarity during development. Summary: Connexin 30 sets the orientation of astroglial motile protrusions during polarized migration in vitro and contributes in vivo to the establishment of hippocampal astrocyte polarity during postnatal maturation.
Collapse
Affiliation(s)
- Grégory Ghézali
- Center for Interdisciplinary Research in Biology, Collège de France, CNRS UMR 7241, INSERM U1050, Labex Memolife, PSL Research University, Paris 75005, France.,Doctoral School N°158, Pierre and Marie Curie University, Paris 75005, France
| | - Charles-Félix Calvo
- Center for Interdisciplinary Research in Biology, Collège de France, CNRS UMR 7241, INSERM U1050, Labex Memolife, PSL Research University, Paris 75005, France
| | - Laure-Elise Pillet
- Center for Interdisciplinary Research in Biology, Collège de France, CNRS UMR 7241, INSERM U1050, Labex Memolife, PSL Research University, Paris 75005, France.,Doctoral School N°562, Paris Descartes University, Paris 75006, France
| | - Flora Llense
- Institut Pasteur, CNRS UMR 3691, Cell Polarity, Migration and Cancer Unit, 25 Rue du Dr Roux, 75724 Paris Cedex 15, France
| | - Pascal Ezan
- Center for Interdisciplinary Research in Biology, Collège de France, CNRS UMR 7241, INSERM U1050, Labex Memolife, PSL Research University, Paris 75005, France
| | - Ulrike Pannasch
- Center for Interdisciplinary Research in Biology, Collège de France, CNRS UMR 7241, INSERM U1050, Labex Memolife, PSL Research University, Paris 75005, France
| | - Alexis-Pierre Bemelmans
- Commissariat à l'Energie Atomique et aux Energies Alternatives (CEA), Département de la Recherche Fondamentale, Institut de biologie François Jacob, MIRCen, and CNRS UMR 9199, Université Paris-Sud, Neurodegenerative Diseases Laboratory, Fontenay-aux-Roses 92260, France
| | - Sandrine Etienne Manneville
- Institut Pasteur, CNRS UMR 3691, Cell Polarity, Migration and Cancer Unit, 25 Rue du Dr Roux, 75724 Paris Cedex 15, France
| | - Nathalie Rouach
- Center for Interdisciplinary Research in Biology, Collège de France, CNRS UMR 7241, INSERM U1050, Labex Memolife, PSL Research University, Paris 75005, France
| |
Collapse
|
4
|
|
5
|
Abstract
Astrocytes dynamic interactions with neurons play an active role in neurotransmission. The gap junction (GJ) subunits connexins 43 and 30 are strongly expressed in astrocytes and have recently been shown to regulate synaptic activity and plasticity. However, the specific role of connexin 43 in the morphological and electrophysiological properties of astrocytes in situ as well as in synaptic transmission remains unknown. Here, we show that connexin 43, a major determinant of astroglial GJ coupling, regulates astrocyte cell volume, but has no impact on astroglial passive membrane properties. Furthermore, we demonstrate that connexin 43 modulates glutamatergic synaptic activity of hippocampal CA1 pyramidal cells. This regulation involves changes in synaptically released glutamate, with no alteration in neuronal excitability or postsynaptic function. These results reveal connexin 43 as a critical player in neuroglial interactions by supporting synaptic efficacy.
Collapse
Affiliation(s)
- Oana Chever
- Neuroglial Interactions in Cerebral Physiopathology, Center for Interdisciplinary Research in Biology, Collège de France, Centre National de la Recherche Scientifique UMR 7241, Institut National de la Santé et de la Recherche Médicale U1050, Labex Memolife, PSL Research University, 75005 Paris, France
| | - Ulrike Pannasch
- Neuroglial Interactions in Cerebral Physiopathology, Center for Interdisciplinary Research in Biology, Collège de France, Centre National de la Recherche Scientifique UMR 7241, Institut National de la Santé et de la Recherche Médicale U1050, Labex Memolife, PSL Research University, 75005 Paris, France
| | - Pascal Ezan
- Neuroglial Interactions in Cerebral Physiopathology, Center for Interdisciplinary Research in Biology, Collège de France, Centre National de la Recherche Scientifique UMR 7241, Institut National de la Santé et de la Recherche Médicale U1050, Labex Memolife, PSL Research University, 75005 Paris, France
| | - Nathalie Rouach
- Neuroglial Interactions in Cerebral Physiopathology, Center for Interdisciplinary Research in Biology, Collège de France, Centre National de la Recherche Scientifique UMR 7241, Institut National de la Santé et de la Recherche Médicale U1050, Labex Memolife, PSL Research University, 75005 Paris, France
| |
Collapse
|
6
|
Johenning FW, Theis AK, Pannasch U, Rückl M, Rüdiger S, Schmitz D. Ryanodine Receptor Activation Induces Long-Term Plasticity of Spine Calcium Dynamics. PLoS Biol 2015; 13:e1002181. [PMID: 26098891 PMCID: PMC4476683 DOI: 10.1371/journal.pbio.1002181] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2015] [Accepted: 05/12/2015] [Indexed: 12/16/2022] Open
Abstract
A key feature of signalling in dendritic spines is the synapse-specific transduction of short electrical signals into biochemical responses. Ca2+ is a major upstream effector in this transduction cascade, serving both as a depolarising electrical charge carrier at the membrane and an intracellular second messenger. Upon action potential firing, the majority of spines are subject to global back-propagating action potential (bAP) Ca2+ transients. These transients translate neuronal suprathreshold activation into intracellular biochemical events. Using a combination of electrophysiology, two-photon Ca2+ imaging, and modelling, we demonstrate that bAPs are electrochemically coupled to Ca2+ release from intracellular stores via ryanodine receptors (RyRs). We describe a new function mediated by spine RyRs: the activity-dependent long-term enhancement of the bAP-Ca2+ transient. Spines regulate bAP Ca2+ influx independent of each other, as bAP-Ca2+ transient enhancement is compartmentalized and independent of the dendritic Ca2+ transient. Furthermore, this functional state change depends exclusively on bAPs travelling antidromically into dendrites and spines. Induction, but not expression, of bAP-Ca2+ transient enhancement is a spine-specific function of the RyR. We demonstrate that RyRs can form specific Ca2+ signalling nanodomains within single spines. Functionally, RyR mediated Ca2+ release in these nanodomains induces a new form of Ca2+ transient plasticity that constitutes a spine specific storage mechanism of neuronal suprathreshold activity patterns. A combination of two-photon calcium imaging, electrophysiology, and modelling shows how ryanodine receptors (a type of intracellular calcium channel) generate a signalling nanodomain within individual dendritic spines, enabling compartmentalized plasticity of calcium dynamics. Experiences change neuronal circuits, and these circuit changes outlast the initial experiences. This means that, in neurons, the fast electrical activity encoding experiences needs to be transduced into longer-lived biochemical and structural changes. A key mediator between these two timescales of neuronal activity is the Ca2+ ion. Ca2+ serves both as an electric charge carrier mediating fast voltage changes at the membrane and as a second messenger activating intracellular signalling cascades. Even within the spatial confines of dendritic spines, the specialized domains of dendrites that receive synaptic connections, Ca2+ encodes a versatile array of specific functions. In this study, we first demonstrate that voltage-gated Ca2+ channels and ryanodine receptors, intracellular channels located on the membrane of the endoplasmic reticulum through which Ca2+ can be released into the cytosol, are electrochemically coupled in single dendritic spines. We identify how ryanodine receptors induce enhancement of the Ca2+ influx, mediated by the opening of voltage-gated Ca2+ channels, induced by action potentials in a compartmentalized, spine-specific manner. Within the femtoliter volume of a single spine, specificity of this route of Ca2+-signalling is achieved by a signalling nanodomain centred on the ryanodine receptor. Our work stresses the role of the ryanodine receptor not only as an ion channel releasing Ca2+ from the endoplasmic reticulum but also as a macromolecular complex generating specificity of Ca2+-signalling within the spatial constraints of a single spine.
Collapse
Affiliation(s)
- Friedrich W. Johenning
- Neuroscience Research Center, Charité-Universitätsmedizin, Berlin, Germany
- Berlin Institute of Health (BIH), Berlin, Germany
- * E-mail:
| | - Anne-Kathrin Theis
- Neuroscience Research Center, Charité-Universitätsmedizin, Berlin, Germany
| | - Ulrike Pannasch
- Neuroscience Research Center, Charité-Universitätsmedizin, Berlin, Germany
| | - Martin Rückl
- Institute of Physics, Humboldt Universität, Berlin, Germany
| | - Sten Rüdiger
- Institute of Physics, Humboldt Universität, Berlin, Germany
| | - Dietmar Schmitz
- Neuroscience Research Center, Charité-Universitätsmedizin, Berlin, Germany
- Bernstein Center for Computational Neuroscience, Berlin, Germany
- Cluster of Excellence ‘NeuroCure’, Charité-Universitätsmedizin, Berlin, Germany
- DZNE- German Center for Neurodegenerative Diseases, Berlin, Germany
| |
Collapse
|
7
|
Seidel JL, Faideau M, Aiba I, Pannasch U, Escartin C, Rouach N, Bonvento G, Shuttleworth CW. Ciliary neurotrophic factor (CNTF) activation of astrocytes decreases spreading depolarization susceptibility and increases potassium clearance. Glia 2015; 63:91-103. [PMID: 25092804 PMCID: PMC5141616 DOI: 10.1002/glia.22735] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [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: 01/27/2014] [Accepted: 07/17/2014] [Indexed: 11/08/2022]
Abstract
Waves of spreading depolarization (SD) have been implicated in the progressive expansion of acute brain injuries. SD can persist over several days, coincident with the time course of astrocyte activation, but little is known about how astrocyte activation may influence SD susceptibility. We examined whether activation of astrocytes modified SD threshold in hippocampal slices. Injection of a lentiviral vector encoding Ciliary neurotrophic factor (CNTF) into the hippocampus in vivo, led to sustained astrocyte activation, verified by up-regulation of glial fibrillary acidic protein (GFAP) at the mRNA and protein levels, as compared to controls injected with vector encoding LacZ. In acute brain slices from LacZ controls, localized 1M KCl microinjections invariably generated SD in CA1 hippocampus, but SD was never induced with this stimulus in CNTF tissues. No significant change in intrinsic excitability was observed in CA1 neurons, but excitatory synaptic transmission was significantly reduced in CNTF samples. mRNA levels of the predominantly astrocytic Na(+) /K(+) -ATPase pump α2 subunit were higher in CNTF samples, and the kinetics of extracellular K(+) transients during matched synaptic activation were consistent with increased K(+) uptake in CNTF tissues. Supporting a role for the Na(+) /K(+) -ATPase pump in increased SD threshold, ouabain, an inhibitor of the pump, was able to generate SD in CNTF tissues. These data support the hypothesis that activated astrocytes can limit SD onset via increased K(+) clearance and suggest that therapeutic strategies targeting these glial cells could improve the outcome following acute brain injuries associated with SD.
Collapse
Affiliation(s)
- Jessica L Seidel
- Department of Neurosciences, University of New Mexico School of Medicine, Albuquerque, New Mexico, USA
| | | | | | | | | | | | | | | |
Collapse
|
8
|
Sibille J, Pannasch U, Rouach N. Astroglial potassium clearance contributes to short-term plasticity of synaptically evoked currents at the tripartite synapse. J Physiol 2013; 592:87-102. [PMID: 24081156 DOI: 10.1113/jphysiol.2013.261735] [Citation(s) in RCA: 101] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Astroglial processes enclose ∼60% of CA1 hippocampal synapses to form the tripartite synapse. Although astrocytes express ionic channels, neurotransmitter receptors and transporters to detect neuronal activity, the nature, plasticity and impact of the currents induced by neuronal activity on short-term synaptic plasticity remain elusive in hippocampal astrocytes. Using simultaneous electrophysiological recordings of astrocytes and neurons, we found that single stimulation of Schaffer collaterals in hippocampal slices evokes in stratum radiatum astrocytes a complex prolonged inward current synchronized to synaptic and spiking activity in CA1 pyramidal cells. The astroglial current is composed of three components sensitive to neuronal activity, i.e. a long-lasting potassium current mediated by Kir4.1 channels, a transient glutamate transporter current and a slow residual current, partially mediated by GABA transporters and Kir4.1-independent potassium channels. We show that all astroglial membrane currents exhibit activity-dependent short-term plasticity. However, only the astroglial glutamate transporter current displays neuronal-like dynamics and plasticity. As Kir4.1 channel-mediated potassium uptake contributes to 80% of the synaptically evoked astroglial current, we investigated in turn its impact on short-term synaptic plasticity. Using glial conditional Kir4.1 knockout mice, we found that astroglial potassium uptake reduces synaptic responses to repetitive stimulation and post-tetanic potentiation. These results show that astrocytes integrate synaptic activity via multiple ionic channels and transporters and contribute to short-term plasticity in part via potassium clearance mediated by Kir4.1 channels.
Collapse
Affiliation(s)
- Jérémie Sibille
- N. Rouach: Neuroglial Interactions in Cerebral Physiopathology, Collège de France, CIRB, CNRS UMR 7241, INSERM U1050, 11, place Marcelin Berthelot, 75005 Paris, France.
| | | | | |
Collapse
|
9
|
Pannasch U, Rouach N. Emerging role for astroglial networks in information processing: from synapse to behavior. Trends Neurosci 2013; 36:405-17. [PMID: 23659852 DOI: 10.1016/j.tins.2013.04.004] [Citation(s) in RCA: 182] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2012] [Revised: 04/01/2013] [Accepted: 04/01/2013] [Indexed: 01/05/2023]
Abstract
Astrocytes contribute to neurotransmission through a variety of mechanisms ranging from synapse isolation to active signaling. Astroglial involvement in neurophysiology has been mostly investigated at the single-cell level. However, a unique feature of astrocytes is their high level of intercellular connectivity mediated by connexins, the proteins forming gap junction (GJ) channels. These astroglial GJ circuits enable the rapid intercellular exchange of ions, metabolites, and neuroactive substances. Recent findings have suggested that, despite their extensity, astroglial networks are also selective, preferential as well as plastic, and can regulate synapses, neuronal circuits, and behavior. The present review critically discusses the impact of astroglial networks on normal and pathological neuronal information processing as well as the underlying mechanisms.
Collapse
Affiliation(s)
- Ulrike Pannasch
- Neuroglial Interactions in Cerebral Physiopathology, Center for Interdisciplinary Research in Biology, Centre Nationale de la Recherche Scientifique (CNRS) Unité Mixte de Recherche 7241, Institut National de la Santé et de la Recherche Médicale (INSERM) Unité 1050, Collège de France, 75005 Paris, France
| | | |
Collapse
|
10
|
Pannasch U, Sibille J, Rouach N. Dual electrophysiological recordings of synaptically-evoked astroglial and neuronal responses in acute hippocampal slices. J Vis Exp 2012:e4418. [PMID: 23222635 PMCID: PMC3564483 DOI: 10.3791/4418] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [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] [Indexed: 12/04/2022] Open
Abstract
Astrocytes form together with neurons tripartite synapses, where they integrate and modulate neuronal activity. Indeed, astrocytes sense neuronal inputs through activation of their ion channels and neurotransmitter receptors, and process information in part through activity-dependent release of gliotransmitters. Furthermore, astrocytes constitute the main uptake system for glutamate, contribute to potassium spatial buffering, as well as to GABA clearance. These cells therefore constantly monitor synaptic activity, and are thereby sensitive indicators for alterations in synaptically-released glutamate, GABA and extracellular potassium levels. Additionally, alterations in astroglial uptake activity or buffering capacity can have severe effects on neuronal functions, and might be overlooked when characterizing physiopathological situations or knockout mice. Dual recording of neuronal and astroglial activities is therefore an important method to study alterations in synaptic strength associated to concomitant changes in astroglial uptake and buffering capacities. Here we describe how to prepare hippocampal slices, how to identify stratum radiatum astrocytes, and how to record simultaneously neuronal and astroglial electrophysiological responses. Furthermore, we describe how to isolate pharmacologically the synaptically-evoked astroglial currents.
Collapse
Affiliation(s)
- Ulrike Pannasch
- Neuroglial Interactions in Cerebral Physiopathology, Center for Interdisciplinary Research in Biology, CNRS UMR 7241, INSERM U1050, Collège de France, France
| | | | | |
Collapse
|
11
|
Abstract
Astrocytes, the third element of the tripartite synapse, are active players in neurotransmission. Up to now, their involvement in neuronal functions has primarily been investigated at the single cell level. However, a key property of astrocytes is that they communicate via extensive networks formed by gap junction channels. Recently, we have shown that this networking modulates the moment to moment basal synaptic transmission and plasticity via the regulation of extracellular potassium and glutamate levels. Here we show that astroglial gap junctional communication also regulates neuronal network activity. We discuss these findings and their implications for brain information processing.
Collapse
Affiliation(s)
- Ulrike Pannasch
- Neuroglial Interactions in Cerebral Physiopathology; Center for Interdisciplinary Research in Biology; Collège de France; CNRS UMR7241; INSERM U1050; Paris, France
| | | | | | | |
Collapse
|
12
|
Peters O, Schipke CG, Philipps A, Haas B, Pannasch U, Wang LP, Benedetti B, Kingston AE, Kettenmann H. Astrocyte Function is Modified by Alzheimer's Disease-like Pathology in Aged Mice. ACTA ACUST UNITED AC 2009; 18:177-89. [DOI: 10.3233/jad-2009-1140] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
- Oliver Peters
- Department of Psychiatry and Psychotherapy, Charité – University Medicine Berlin, Campus Benjamin Franklin, Berlin, Germany
| | - Carola G. Schipke
- Department of Psychiatry and Psychotherapy, Charité – University Medicine Berlin, Campus Benjamin Franklin, Berlin, Germany
| | - Andreas Philipps
- Cellular Neurosciences, Max Delbrück Center for Molecular Medicine (MDC), Berlin, Germany
| | | | | | - Li Ping Wang
- Institute of Biomedical and Health Engineering, Shenzhen Institute of Advanced Technology, Chinese Academy of Science, Shenzhen, China
| | - Bruno Benedetti
- Cellular Neurosciences, Max Delbrück Center for Molecular Medicine (MDC), Berlin, Germany
| | - Ann E. Kingston
- Lilly Research Laboratories, Neuroscience Division; Eli Lilly & Company, Lilly Corporate Center, Indianapolis, Indiana, USA
| | - Helmut Kettenmann
- Cellular Neurosciences, Max Delbrück Center for Molecular Medicine (MDC), Berlin, Germany
| |
Collapse
|
13
|
Färber K, Markworth S, Pannasch U, Nolte C, Prinz V, Kronenberg G, Gertz K, Endres M, Bechmann I, Enjyoji K, Robson SC, Kettenmann H. The ectonucleotidase cd39/ENTPDase1 modulates purinergic-mediated microglial migration. Glia 2008; 56:331-41. [PMID: 18098126 DOI: 10.1002/glia.20606] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Microglia is activated by brain injury. They migrate in response to ATP and although adenosine alone has no effect on wild type microglial migration, we show that inhibition of adenosine receptors impedes ATP triggered migration. CD39 is the dominant cellular ectonucleotidase that degrades nucleotides to nucleosides, including adenosine. Importantly, ATP fails to stimulate P2 receptor mediated migration in cd39(-/-) microglia. However, the effects of ATP on migration in cd39(-/-) microglia can be restored by co-stimulation with adenosine or by addition of a soluble ectonucleotidase. We also tested the impact of cd39-deletion in a model of ischemia, in an entorhinal cortex lesion and in the facial nucleus after facial nerve lesion. The accumulation of microglia at the pathological sites was markedly decreased in cd39(-/-) animals. We conclude that the co-stimulation of purinergic and adenosine receptors is a requirement for microglial migration and that the expression of cd39 controls the ATP/adenosine balance.
Collapse
Affiliation(s)
- Katrin Färber
- Cellular Neuroscience, Max-Delbrück-Center for Molecular Medicine, Berlin, Germany
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
14
|
Noda M, Kariura Y, Pannasch U, Nishikawa K, Wang L, Seike T, Ifuku M, Kosai Y, Wang B, Nolte C, Aoki S, Kettenmann H, Wada K. Neuroprotective role of bradykinin because of the attenuation of pro-inflammatory cytokine release from activated microglia. J Neurochem 2007; 101:397-410. [PMID: 17402969 DOI: 10.1111/j.1471-4159.2006.04339.x] [Citation(s) in RCA: 98] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Bradykinin (BK) has been reported to be a mediator of brain damage in acute insults. Receptors for BK have been identified on microglia, the pathologic sensors of the brain. Here, we report that BK attenuated lipopolysaccharide (LPS)-induced release of tumor necrosis factor-alpha (TNF-alpha) and interleukin-1beta from microglial cells, thus acting as an anti-inflammatory mediator in the brain. This effect was mimicked by raising intracellular cAMP or stimulating the prostanoid receptors EP2 and EP4, while it was abolished by a cAMP antagonist, a prostanoid receptor antagonist, or by an inhibitor of the inducible cyclooxygenase (cyclooxygenase-2). BK also enhanced formation of prostaglandin E(2) and expression of microsomal prostaglandin E synthase. Expression of BK receptors and EP2/EP4 receptors were also enhanced. Using physiological techniques, we identified functional BK receptors not only in culture, but also in microglia from acute brain slices. BK reduced LPS-induced neuronal death in neuron-microglia co-cultures. This was probably mediated via microglia as it did not affect TNF-alpha-induced neuronal death in pure neuronal cultures. Our data imply that BK has anti-inflammatory and neuroprotective effects in the central nervous system by modulating microglial function.
Collapse
MESH Headings
- Alprostadil/metabolism
- Animals
- Animals, Newborn
- Anti-Inflammatory Agents/immunology
- Anti-Inflammatory Agents/metabolism
- Anti-Inflammatory Agents/pharmacology
- Bradykinin/immunology
- Bradykinin/metabolism
- Bradykinin/pharmacology
- Cells, Cultured
- Coculture Techniques
- Cyclic AMP/metabolism
- Cytokines/immunology
- Cytokines/metabolism
- Cytoprotection/immunology
- Encephalitis/immunology
- Encephalitis/metabolism
- Encephalitis/physiopathology
- Gliosis/chemically induced
- Gliosis/immunology
- Gliosis/metabolism
- Interleukin-1beta/immunology
- Interleukin-1beta/metabolism
- Lipopolysaccharides
- Mice
- Mice, Inbred C57BL
- Microglia/immunology
- Microglia/metabolism
- Nerve Degeneration/immunology
- Nerve Degeneration/metabolism
- Nerve Degeneration/physiopathology
- Organ Culture Techniques
- Rats
- Rats, Wistar
- Receptors, Bradykinin/drug effects
- Receptors, Bradykinin/metabolism
- Receptors, Prostaglandin E/antagonists & inhibitors
- Receptors, Prostaglandin E/metabolism
- Receptors, Prostaglandin E, EP4 Subtype
- Tumor Necrosis Factor-alpha/immunology
- Tumor Necrosis Factor-alpha/metabolism
Collapse
Affiliation(s)
- Mami Noda
- Laboratory of Pathophysiology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
15
|
Pannasch U, Färber K, Nolte C, Blonski M, Yan Chiu S, Messing A, Kettenmann H. The potassium channels Kv1.5 and Kv1.3 modulate distinct functions of microglia. Mol Cell Neurosci 2006; 33:401-11. [PMID: 17055293 DOI: 10.1016/j.mcn.2006.08.009] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.2] [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: 04/25/2006] [Revised: 08/16/2006] [Accepted: 08/30/2006] [Indexed: 11/18/2022] Open
Abstract
Activation of microglia by LPS leads to an induction of cytokine and NO release, reduced proliferation and increased outward K(+) conductance, the latter involving the activation of Kv1.5 and Kv1.3 channels. We studied the role of these channels for microglial function using two strategies to interfere with channel expression, a Kv1.5 knockout (Kv1.5(-/-)) mouse and an antisense oligonucleotide (AO) approach. The LPS-induced NO release was reduced by AO Kv1.5 and completely absent in the Kv1.5(-/-) animal; the AO Kv1.3 had no effect. In contrast, proliferation was augmented with both, loss of Kv1.3 or Kv1.5 channel expression. After facial nerve lesion, proliferation rate was higher in Kv1.5(-/-) animals as compared to wild type. Patch clamp experiments confirmed the reduction of the LPS-induced outward current amplitude in Kv1.5(-/-) microglia as well as in Kv1.5- or Kv1.3 AO-treated cells. Our study indicates that induction of K(+) channel expression is a prerequisite for the full functional spectrum of microglial activation.
Collapse
Affiliation(s)
- Ulrike Pannasch
- Cellular Neuroscience, Max-Delbrück-Center for Molecular Medicine, Robert-Rössle-Strasse 10, 13125 Berlin, Germany
| | | | | | | | | | | | | |
Collapse
|
16
|
Färber K, Pannasch U, Kettenmann H. Dopamine and noradrenaline control distinct functions in rodent microglial cells. Mol Cell Neurosci 2005; 29:128-38. [PMID: 15866053 DOI: 10.1016/j.mcn.2005.01.003] [Citation(s) in RCA: 175] [Impact Index Per Article: 9.2] [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: 06/10/2004] [Revised: 01/06/2005] [Accepted: 01/12/2005] [Indexed: 11/26/2022] Open
Abstract
Microglial cells are the immune-competent elements of the brain. They not only express receptors for chemokines and cytokines but also for neurotransmitters such as GABA [Charles et al., Mol. Cell Neurosci. 24 (2003) 214], glutamate [Noda et al., J. Neurosci. 20 (2000) 251], and adrenaline [Mori et al., Neuropharmacology 43 (2002) 1026]. Here we report the functional expression of dopamine receptors in mouse and rat microglia, in culture and brain slices. Using the patch clamp technique as the functional assay we identified D1- and D2-like dopamine receptors using subtype-specific ligands. They triggered the inhibition of the constitutive potassium inward rectifier and activated potassium outward currents in a subpopulation of microglia. Chronic dopamine receptor stimulation enhanced migratory activity and attenuated the lipopolysaccharide (LPS)-induced nitric oxide (NO) release similar as by stimulation of adrenergic receptors. While, however, noradrenaline attenuated the LPS-induced release of TNF-alpha and IL-6, dopamine was ineffective in modulating this response. We conclude that microglia express dopamine receptors which are distinct in function from adrenergic receptors.
Collapse
MESH Headings
- Adrenergic Agonists/pharmacology
- Animals
- Cell Movement/drug effects
- Cell Movement/physiology
- Cells, Cultured
- Cytokines/metabolism
- Dopamine/pharmacology
- Lipopolysaccharides/pharmacology
- Membrane Potentials/drug effects
- Mice
- Mice, Inbred Strains
- Microglia/cytology
- Microglia/drug effects
- Microglia/physiology
- Nitric Oxide/metabolism
- Norepinephrine/pharmacology
- Organ Culture Techniques
- Patch-Clamp Techniques
- Potassium/metabolism
- RNA, Messenger/analysis
- Rats
- Rats, Wistar
- Receptors, Adrenergic, alpha/physiology
- Receptors, Adrenergic, beta/physiology
- Receptors, Dopamine D1/agonists
- Receptors, Dopamine D1/genetics
- Receptors, Dopamine D1/physiology
- Receptors, Dopamine D2/agonists
- Receptors, Dopamine D2/genetics
- Receptors, Dopamine D2/physiology
- Sympathomimetics/pharmacology
Collapse
Affiliation(s)
- Katrin Färber
- Cellular Neuroscience, Max-Delbrueck-Center for Molecular Medicine, Robert-Rössle-Strasse 10, 13125 Berlin, Germany
| | | | | |
Collapse
|