1
|
Cheung G, Chever O, Rollenhagen A, Quenech'du N, Ezan P, Lübke JHR, Rouach N. Astroglial Connexin 43 Regulates Synaptic Vesicle Release at Hippocampal Synapses. Cells 2023; 12:cells12081133. [PMID: 37190042 DOI: 10.3390/cells12081133] [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] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Revised: 04/01/2023] [Accepted: 04/03/2023] [Indexed: 05/17/2023] Open
Abstract
Connexin 43, an astroglial gap junction protein, is enriched in perisynaptic astroglial processes and plays major roles in synaptic transmission. We have previously found that astroglial Cx43 controls synaptic glutamate levels and allows for activity-dependent glutamine release to sustain physiological synaptic transmissions and cognitiogns. However, whether Cx43 is important for the release of synaptic vesicles, which is a critical component of synaptic efficacy, remains unanswered. Here, using transgenic mice with a glial conditional knockout of Cx43 (Cx43-/-), we investigate whether and how astrocytes regulate the release of synaptic vesicles from hippocampal synapses. We report that CA1 pyramidal neurons and their synapses develop normally in the absence of astroglial Cx43. However, a significant impairment in synaptic vesicle distribution and release dynamics were observed. In particular, the FM1-43 assays performed using two-photon live imaging and combined with multi-electrode array stimulation in acute hippocampal slices, revealed a slower rate of synaptic vesicle release in Cx43-/- mice. Furthermore, paired-pulse recordings showed that synaptic vesicle release probability was also reduced and is dependent on glutamine supply via Cx43 hemichannel (HC). Taken together, we have uncovered a role for Cx43 in regulating presynaptic functions by controlling the rate and probability of synaptic vesicle release. Our findings further highlight the significance of astroglial Cx43 in synaptic transmission and efficacy.
Collapse
Affiliation(s)
- Giselle Cheung
- Neuroglial Interactions in Cerebral Physiology and Pathologies, Center for Interdisciplinary Research in Biology, Collège de France, CNRS, INSERM, Labex Memolife, Université PSL, 75231 Paris, France
| | - Oana Chever
- Neuroglial Interactions in Cerebral Physiology and Pathologies, Center for Interdisciplinary Research in Biology, Collège de France, CNRS, INSERM, Labex Memolife, Université PSL, 75231 Paris, France
| | - Astrid Rollenhagen
- Institute for Neuroscience and Medicine INM-10, Research Center Jülich, 52428 Jülich, Germany
- Jülich-Aachen Research Alliance Translational Brain Medicine, 52056 Aachen, Germany
| | - Nicole Quenech'du
- Neuroglial Interactions in Cerebral Physiology and Pathologies, Center for Interdisciplinary Research in Biology, Collège de France, CNRS, INSERM, Labex Memolife, Université PSL, 75231 Paris, France
| | - Pascal Ezan
- Neuroglial Interactions in Cerebral Physiology and Pathologies, Center for Interdisciplinary Research in Biology, Collège de France, CNRS, INSERM, Labex Memolife, Université PSL, 75231 Paris, France
| | - Joachim H R Lübke
- Institute for Neuroscience and Medicine INM-10, Research Center Jülich, 52428 Jülich, Germany
- Jülich-Aachen Research Alliance Translational Brain Medicine, 52056 Aachen, Germany
- Department of Psychiatry, Psychotherapy and Psychosomatics, Rheinisch-Westfaelische Technische Hochschule Aachen University, 52056 Aachen, Germany
| | - Nathalie Rouach
- Neuroglial Interactions in Cerebral Physiology and Pathologies, Center for Interdisciplinary Research in Biology, Collège de France, CNRS, INSERM, Labex Memolife, Université PSL, 75231 Paris, France
| |
Collapse
|
2
|
Chever O, Zerimech S, Scalmani P, Lemaire L, Pizzamiglio L, Loucif A, Ayrault M, Krupa M, Desroches M, Duprat F, Léna I, Cestèle S, Mantegazza M. Initiation of migraine-related cortical spreading depolarization by hyperactivity of GABAergic neurons and NaV1.1 channels. J Clin Invest 2021; 131:e142203. [PMID: 34491914 PMCID: PMC8553565 DOI: 10.1172/jci142203] [Citation(s) in RCA: 6] [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: 07/16/2020] [Accepted: 09/02/2021] [Indexed: 01/24/2023] Open
Abstract
Spreading depolarizations (SDs) are involved in migraine, epilepsy, stroke, traumatic brain injury, and subarachnoid hemorrhage. However, the cellular origin and specific differential mechanisms are not clear. Increased glutamatergic activity is thought to be the key factor for generating cortical spreading depression (CSD), a pathological mechanism of migraine. Here, we show that acute pharmacological activation of NaV1.1 (the main Na+ channel of interneurons) or optogenetic-induced hyperactivity of GABAergic interneurons is sufficient to ignite CSD in the neocortex by spiking-generated extracellular K+ build-up. Neither GABAergic nor glutamatergic synaptic transmission were required for CSD initiation. CSD was not generated in other brain areas, suggesting that this is a neocortex-specific mechanism of CSD initiation. Gain-of-function mutations of NaV1.1 (SCN1A) cause familial hemiplegic migraine type-3 (FHM3), a subtype of migraine with aura, of which CSD is the neurophysiological correlate. Our results provide the mechanism linking NaV1.1 gain of function to CSD generation in FHM3. Thus, we reveal the key role of hyperactivity of GABAergic interneurons in a mechanism of CSD initiation, which is relevant as a pathological mechanism of Nav1.1 FHM3 mutations, and possibly also for other types of migraine and diseases in which SDs are involved.
Collapse
Affiliation(s)
- Oana Chever
- Université Côte d'Azur and.,CNRS UMR7275, Institute of Molecular and Cellular Pharmacology (IPMC), Valbonne-Sophia Antipolis, France
| | - Sarah Zerimech
- Université Côte d'Azur and.,CNRS UMR7275, Institute of Molecular and Cellular Pharmacology (IPMC), Valbonne-Sophia Antipolis, France
| | - Paolo Scalmani
- Unità Operativa VII Clinical and Experimental Epileptology, Foundation IRCCS Neurological Institute Carlo Besta, Milan, Italy
| | - Louisiane Lemaire
- Inria Sophia Antipolis Méditerranée, MathNeuro Project Team, Valbonne-Sophia Antipolis, France
| | - Lara Pizzamiglio
- Université Côte d'Azur and.,CNRS UMR7275, Institute of Molecular and Cellular Pharmacology (IPMC), Valbonne-Sophia Antipolis, France
| | - Alexandre Loucif
- Université Côte d'Azur and.,CNRS UMR7275, Institute of Molecular and Cellular Pharmacology (IPMC), Valbonne-Sophia Antipolis, France
| | - Marion Ayrault
- Université Côte d'Azur and.,CNRS UMR7275, Institute of Molecular and Cellular Pharmacology (IPMC), Valbonne-Sophia Antipolis, France
| | - Martin Krupa
- Université Côte d'Azur, Laboratoire Jean-Alexandre Dieudonné, Nice, France
| | - Mathieu Desroches
- Inria Sophia Antipolis Méditerranée, MathNeuro Project Team, Valbonne-Sophia Antipolis, France
| | - Fabrice Duprat
- Université Côte d'Azur and.,CNRS UMR7275, Institute of Molecular and Cellular Pharmacology (IPMC), Valbonne-Sophia Antipolis, France.,INSERM, Valbonne-Sophia Antipolis, France
| | - Isabelle Léna
- Université Côte d'Azur and.,CNRS UMR7275, Institute of Molecular and Cellular Pharmacology (IPMC), Valbonne-Sophia Antipolis, France
| | - Sandrine Cestèle
- Université Côte d'Azur and.,CNRS UMR7275, Institute of Molecular and Cellular Pharmacology (IPMC), Valbonne-Sophia Antipolis, France
| | - Massimo Mantegazza
- Université Côte d'Azur and.,CNRS UMR7275, Institute of Molecular and Cellular Pharmacology (IPMC), Valbonne-Sophia Antipolis, France.,INSERM, Valbonne-Sophia Antipolis, France
| |
Collapse
|
3
|
Castel H, Laillet De Montulle E, Dubois M, Ferracci F, Mutel A, Dembele K, Desrues L, Derrey S, Langlois O, Chever O, Gandolfo P, Morin F. P13.10 Chemoattraction of glioma cells in a local hydrogel trap and immune control associated with improved survival and cognitive functions in a mouse model of glioblastoma resection. Neuro Oncol 2021. [DOI: 10.1093/neuonc/noab180.118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Abstract
BACKGROUND
Glioblastoma (GB) is the most aggressive brain primary tumor. The prognosis remains poor mainly due to the invasiveness of glioma cells, radio and/or chemoresistance and GB-induced immunosuppressive environment. Here, we propose to use a local delivery system based on a biocompatible hydrogel containing the chemopeptide urotensin II (hUII) or a biased synthetic analog DAB8-hUII, to “trap” GB cells, and/or to control immune cells expressing its G protein-coupled receptor UT, leading to tumor regression and neurological benefit, in a mouse model of GB resection.
MATERIAL AND METHODS
In vitro, invasion towards UII/analog across different hydrogels or glue of human or murine GB-GFP cell lines was evaluated in Boyden chamber and cloning ring assays. In vivo GB cells were intrastriatally xenografted, then resected while hydrogel- or glue-containing UII/analog was injected in the cavity resection. Behavioral tests, brain immunohistochemical analyses and mouse survival were then investigated.
RESULTS
In vitro, invasive capacity of human U87 and 42MG or murine GL261 and CT2A GB cells was stimulated by UII loaded into hydrogel-based hyaluronic acid supplemented with collagen or other chemicals, PNIPAAm-PEG, or thrombin-fibrin glue. In vivo, injection of UII- or DAB8-hUII-loaded glue into the cavity resection of GL261 and CT2A GB in C57BL/6 mice significantly improved survival compared with tumor and resected experimental conditions. Neurological status was also tested before and after GB resection. We found that GL261 and CT2A cell-bearing mice expressed altered spontaneous activity, emotion and cognitive functions. Intracavity injection of the glue improved resignation and anxiety and increased motor activity and cognition with a best cognitive recovery with hUII and DAB-8-hUII-loaded glue groups. Ex vivo brain analyses revealed high expression of UT and UII in some GB GFP-positive cells and macrophages within GB core and at the interface with the normal brain, GB cells expressing UT migrating along tortuous podocalyxin+ vascular components. In brains bearing hydrogel/hUII glue, vascularization appears modified and GFAP+ astrocytes and F4/80+ macrophages were highly recruited in the border of the cavity, compared with the other conditions.
CONCLUSION
A local glue containing UII may trap GB cells and remodel the tumor microenvironment responsible for survival and cognitive improvements, providing new option in the therapeutic arsenal of GB.
Collapse
Affiliation(s)
- H Castel
- INSERM U1239, Mont-Saint-Aignan, France
| | | | - M Dubois
- INSERM U1239, Mont-Saint-Aignan, France
| | | | - A Mutel
- INSERM U1239, Mont-Saint-Aignan, France
| | - K Dembele
- INSERM U1239, Mont-Saint-Aignan, France
| | - L Desrues
- INSERM U1239, Mont-Saint-Aignan, France
| | - S Derrey
- Neurosurgery Service, Rouen CHU Hospital, Rouen, France
| | - O Langlois
- Inserm U1239, Neurosurgery Service, Rouen CHU Hospital, Mont-Saint-Aignan, France
| | - O Chever
- INSERM U1239, Mont-Saint-Aignan, France
| | | | - F Morin
- INSERM U1239, Mont-Saint-Aignan, France
| |
Collapse
|
4
|
Abstract
Malignant glioma including glioblastoma (GBM) is the most common group of primary brain tumors. Despite standard optimized treatment consisting of extensive resection followed by radiotherapy/concomitant and adjuvant therapy, GBM remains one of the most aggressive human cancers. GBM is a typical example of intra-heterogeneity modeled by different micro-environmental situations, one of the main causes of resistance to conventional treatments. The resistance to treatment is associated with angiogenesis, hypoxic and necrotic tumor areas while heterogeneity would accumulate during glioma cell invasion, supporting recurrence. These complex mechanisms require a focus on potential new molecular actors to consider new treatment options for gliomas. Among emerging and underexplored targets, transient receptor potential (TRP) channels belonging to a superfamily of non-selective cation channels which play critical roles in the responses to a number of external stimuli from the external environment were found to be related to cancer development, including glioma. Here, we discuss the potential as biological markers of diagnosis and prognosis of TRPC6, TRPM8, TRPV4, or TRPV1/V2 being associated with glioma patient overall survival. TRPs-inducing common or distinct mechanisms associated with their Ca2+-channel permeability and/or kinase function were detailed as involving miRNA or secondary effector signaling cascades in turn controlling proliferation, cell cycle, apoptotic pathways, DNA repair, resistance to treatment as well as migration/invasion. These recent observations of the key role played by TRPs such as TRPC6 in GBM growth and invasiveness, TRPV2 in proliferation and glioma-stem cell differentiation and TRPM2 as channel carriers of cytotoxic chemotherapy within glioma cells, should offer new directions for innovation in treatment strategies of high-grade glioma as GBM to overcome high resistance and recurrence.
Collapse
Affiliation(s)
- Giorgia Chinigò
- Laboratory of Cell Physiology, Department of Life Sciences, Univ. Lille, Inserm, U1003 - PHYCEL, University of Lille, Lille, France.,Laboratory of Cellular and Molecular Angiogenesis, Department of Life Sciences and Systems Biology, University of Torino, Turin, Italy
| | - Hélène Castel
- UNIROUEN, Inserm U1239, DC2N, Normandie Université, Rouen, France.,Institute for Research and Innovation in Biomedicine, Rouen, France
| | - Oana Chever
- UNIROUEN, Inserm U1239, DC2N, Normandie Université, Rouen, France.,Institute for Research and Innovation in Biomedicine, Rouen, France
| | - Dimitra Gkika
- CNRS, Inserm, CHU Lille, Centre Oscar Lambret, UMR 9020-UMR 1277-Canther-Cancer Heterogeneity, Plasticity and Resistance to Therapies, University of Lille, Lille, France.,Institut Universitaire de France, Paris, France
| |
Collapse
|
5
|
Cohen-Salmon M, Slaoui L, Mazaré N, Gilbert A, Oudart M, Alvear-Perez R, Elorza-Vidal X, Chever O, Boulay AC. Astrocytes in the regulation of cerebrovascular functions. Glia 2020; 69:817-841. [PMID: 33058289 DOI: 10.1002/glia.23924] [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] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Revised: 09/18/2020] [Accepted: 09/21/2020] [Indexed: 12/18/2022]
Abstract
Astrocytes are the most numerous type of neuroglia in the brain and have a predominant influence on the cerebrovascular system; they control perivascular homeostasis, the integrity of the blood-brain barrier, the dialogue with the peripheral immune system, the transfer of metabolites from the blood, and blood vessel contractility in response to neuronal activity. These regulatory processes occur in a specialized interface composed of perivascular astrocyte extensions that almost completely cover the cerebral blood vessels. Scientists have only recently started to study how this interface is formed and how it influences cerebrovascular functions. Here, we review the literature on the astrocytes' role in the regulation of the cerebrovascular system. We cover the anatomy and development of the gliovascular interface, the known gliovascular functions, and molecular factors, the latter's implication in certain pathophysiological situations, and recent cutting-edge experimental tools developed to examine the astrocytes' role at the vascular interface. Finally, we highlight some open questions in this field of research.
Collapse
Affiliation(s)
- Martine Cohen-Salmon
- Physiology and Physiopathology of the Gliovascular Unit Research Group, Center for Interdisciplinary Research in Biology (CIRB), College de France, CNRS Unité Mixte de Recherche 724, INSERM Unité 1050, Labex Memolife, PSL Research University, Paris, France
| | - Leila Slaoui
- Physiology and Physiopathology of the Gliovascular Unit Research Group, Center for Interdisciplinary Research in Biology (CIRB), College de France, CNRS Unité Mixte de Recherche 724, INSERM Unité 1050, Labex Memolife, PSL Research University, Paris, France
| | - Noémie Mazaré
- Physiology and Physiopathology of the Gliovascular Unit Research Group, Center for Interdisciplinary Research in Biology (CIRB), College de France, CNRS Unité Mixte de Recherche 724, INSERM Unité 1050, Labex Memolife, PSL Research University, Paris, France
| | - Alice Gilbert
- Physiology and Physiopathology of the Gliovascular Unit Research Group, Center for Interdisciplinary Research in Biology (CIRB), College de France, CNRS Unité Mixte de Recherche 724, INSERM Unité 1050, Labex Memolife, PSL Research University, Paris, France
| | - Marc Oudart
- Physiology and Physiopathology of the Gliovascular Unit Research Group, Center for Interdisciplinary Research in Biology (CIRB), College de France, CNRS Unité Mixte de Recherche 724, INSERM Unité 1050, Labex Memolife, PSL Research University, Paris, France
| | - Rodrigo Alvear-Perez
- Physiology and Physiopathology of the Gliovascular Unit Research Group, Center for Interdisciplinary Research in Biology (CIRB), College de France, CNRS Unité Mixte de Recherche 724, INSERM Unité 1050, Labex Memolife, PSL Research University, Paris, France
| | - Xabier Elorza-Vidal
- Physiology and Physiopathology of the Gliovascular Unit Research Group, Center for Interdisciplinary Research in Biology (CIRB), College de France, CNRS Unité Mixte de Recherche 724, INSERM Unité 1050, Labex Memolife, PSL Research University, Paris, France
| | - Oana Chever
- Normandie University, UNIROUEN, INSERM, DC2N, IRIB, Rouen, France
| | - Anne-Cécile Boulay
- Physiology and Physiopathology of the Gliovascular Unit Research Group, Center for Interdisciplinary Research in Biology (CIRB), College de France, CNRS Unité Mixte de Recherche 724, INSERM Unité 1050, Labex Memolife, PSL Research University, Paris, France
| |
Collapse
|
6
|
Zerimech S, Chever O, Scalmani P, Pizzamiglio L, Duprat F, Mantegazza M. Cholinergic modulation inhibits cortical spreading depression in mouse neocortex through activation of muscarinic receptors and decreased excitatory/inhibitory drive. Neuropharmacology 2020; 166:107951. [PMID: 31945385 DOI: 10.1016/j.neuropharm.2020.107951] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [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: 11/05/2019] [Revised: 01/06/2020] [Accepted: 01/09/2020] [Indexed: 12/20/2022]
Abstract
Cortical spreading depression (CSD) is a wave of transient network hyperexcitability leading to long lasting depolarization and block of firing, which initiates focally and slowly propagates in the cerebral cortex. It causes migraine aura and it has been implicated in the generation of migraine headache. Cortical excitability can be modulated by cholinergic actions, leading in neocortical slices to the generation of rhythmic synchronous activities (UP/DOWN states). We investigated the effect of cholinergic activation with the cholinomimetic agonist carbachol on CSD triggered with 130 mM KCl pulse injections in acute mouse neocortical brain slices, hypothesizing that the cholinergic-induced increase of cortical network excitability during UP states could facilitate CSD. We observed instead an inhibitory effect of cholinergic activation on both initiation and propagation of CSD, through the action of muscarinic receptors. In fact, carbachol-induced CSD inhibition was blocked by atropine or by the preferential M1 muscarinic antagonist telenzepine; the preferential M1 muscarinic agonist McN-A-343 inhibited CSD similarly to carbachol, and its effect was blocked by telenzepine. Recordings of spontaneous excitatory and inhibitory post-synaptic currents in pyramidal neurons showed that McN-A-343 induced overall a decrease of the excitatory/inhibitory ratio. This inhibitory action may be targeted for novel pharmacological approaches in the treatment of migraine with muscarinic agonists.
Collapse
Affiliation(s)
- Sarah Zerimech
- Université Côte d'Azur, Valbonne-Sophia Antipolis, France; CNRS UMR7275, Institute of Molecular and Cellular Pharmacology (IPMC), Valbonne-Sophia Antipolis, France
| | - Oana Chever
- Université Côte d'Azur, Valbonne-Sophia Antipolis, France; CNRS UMR7275, Institute of Molecular and Cellular Pharmacology (IPMC), Valbonne-Sophia Antipolis, France
| | - Paolo Scalmani
- U.O. VII Clinical Epileptology and Experimental Neurophysiology, Foundation IRCCS Neurological Institute Carlo Besta, Milan, Italy
| | - Lara Pizzamiglio
- Université Côte d'Azur, Valbonne-Sophia Antipolis, France; CNRS UMR7275, Institute of Molecular and Cellular Pharmacology (IPMC), Valbonne-Sophia Antipolis, France
| | - Fabrice Duprat
- Université Côte d'Azur, Valbonne-Sophia Antipolis, France; CNRS UMR7275, Institute of Molecular and Cellular Pharmacology (IPMC), Valbonne-Sophia Antipolis, France; Inserm, Valbonne-Sophia Antipolis, France
| | - Massimo Mantegazza
- Université Côte d'Azur, Valbonne-Sophia Antipolis, France; CNRS UMR7275, Institute of Molecular and Cellular Pharmacology (IPMC), Valbonne-Sophia Antipolis, France; Inserm, Valbonne-Sophia Antipolis, France.
| |
Collapse
|
7
|
Dossi E, Blauwblomme T, Moulard J, Chever O, Vasile F, Guinard E, Le Bert M, Couillin I, Pallud J, Capelle L, Huberfeld G, Rouach N. Pannexin-1 channels contribute to seizure generation in human epileptic brain tissue and in a mouse model of epilepsy. Sci Transl Med 2019; 10:10/443/eaar3796. [PMID: 29848662 DOI: 10.1126/scitranslmed.aar3796] [Citation(s) in RCA: 70] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2017] [Revised: 11/02/2017] [Accepted: 05/10/2018] [Indexed: 01/08/2023]
Abstract
Epilepsies are characterized by recurrent seizures, which disrupt normal brain function. Alterations in neuronal excitability and excitation-inhibition balance have been shown to promote seizure generation, yet molecular determinants of such alterations remain to be identified. Pannexin channels are nonselective, large-pore channels mediating extracellular exchange of neuroactive molecules. Recent data suggest that these channels are activated under pathological conditions and regulate neuronal excitability. However, whether pannexin channels sustain or counteract chronic epilepsy in human patients remains unknown. We studied the impact of pannexin-1 channel activation in postoperative human tissue samples from patients with epilepsy displaying epileptic activity ex vivo. These samples were obtained from surgical resection of epileptogenic zones in patients suffering from lesional or drug-resistant epilepsy. We found that pannexin-1 channel activation promoted seizure generation and maintenance through adenosine triphosphate signaling via purinergic 2 receptors. Pharmacological inhibition of pannexin-1 channels with probenecid or mefloquine-two medications currently used for treating gout and malaria, respectively-blocked ictal discharges in human cortical brain tissue slices. Genetic deletion of pannexin-1 channels in mice had anticonvulsant effects when the mice were exposed to kainic acid, a model of temporal lobe epilepsy. Our data suggest a proepileptic role of pannexin-1 channels in chronic epilepsy in human patients and that pannexin-1 channel inhibition might represent an alternative therapeutic strategy for treating lesional and drug-resistant epilepsies.
Collapse
Affiliation(s)
- Elena Dossi
- Neuroglial Interactions in Cerebral Physiopathology, Center for Interdisciplinary Research in Biology, Collège de France, CNR UMR 7241, INSERM U1050, Labex Memolife, PSL Research University, 75005 Paris, France
| | - Thomas Blauwblomme
- Assistance Publique-Hopitaux de Paris (AP-HP), Department of Pediatric Neurosurgery, Necker Hospital, INSERM U1129, Paris Descartes University, PRES Sorbonne Paris Cité, 75015 Paris, France.,INSERM U1129, Paris Descartes University, PRES Sorbonne Paris Cité, CEA, 75015 Paris, France
| | - Julien Moulard
- Neuroglial Interactions in Cerebral Physiopathology, Center for Interdisciplinary Research in Biology, Collège de France, CNR UMR 7241, INSERM U1050, Labex Memolife, PSL Research University, 75005 Paris, France
| | - Oana Chever
- Neuroglial Interactions in Cerebral Physiopathology, Center for Interdisciplinary Research in Biology, Collège de France, CNR UMR 7241, INSERM U1050, Labex Memolife, PSL Research University, 75005 Paris, France
| | - Flora Vasile
- Neuroglial Interactions in Cerebral Physiopathology, Center for Interdisciplinary Research in Biology, Collège de France, CNR UMR 7241, INSERM U1050, Labex Memolife, PSL Research University, 75005 Paris, France
| | - Eleonore Guinard
- Neuroglial Interactions in Cerebral Physiopathology, Center for Interdisciplinary Research in Biology, Collège de France, CNR UMR 7241, INSERM U1050, Labex Memolife, PSL Research University, 75005 Paris, France.,INSERM U1129, Paris Descartes University, PRES Sorbonne Paris Cité, CEA, 75015 Paris, France
| | - Marc Le Bert
- CNRS UMR7355, Experimental and Molecular Immunology and Neurogenetics, 45067 Orléans, France
| | - Isabelle Couillin
- CNRS UMR7355, Experimental and Molecular Immunology and Neurogenetics, 45067 Orléans, France
| | - Johan Pallud
- Department of Neurosurgery, Sainte-Anne Hospital and IMA-BRAIN, INSERM U894, Paris Descartes University, PRES Sorbonne Paris Cité, 75014 Paris, France
| | - Laurent Capelle
- Department of Neurosurgery, University Pierre and Marie Curie, La Pitié-Salpêtrière Hospital, AP-HP, Sorbonne Universités, 75013 Paris, France
| | - Gilles Huberfeld
- Neuroglial Interactions in Cerebral Physiopathology, Center for Interdisciplinary Research in Biology, Collège de France, CNR UMR 7241, INSERM U1050, Labex Memolife, PSL Research University, 75005 Paris, France.,INSERM U1129, Paris Descartes University, PRES Sorbonne Paris Cité, CEA, 75015 Paris, France.,Department of Neurophysiology, La Pitié-Salpetrière Hospital, Sorbonne Universités, University Pierre and Marie Curie, AP-HP, 75013 Paris, France
| | - Nathalie Rouach
- Neuroglial Interactions in Cerebral Physiopathology, Center for Interdisciplinary Research in Biology, Collège de France, CNR UMR 7241, INSERM U1050, Labex Memolife, PSL Research University, 75005 Paris, France.
| |
Collapse
|
8
|
Helleringer R, Chever O, Daniel H, Galante M. Oxygen and Glucose Deprivation Induces Bergmann Glia Membrane Depolarization and Ca 2+ Rises Mainly Mediated by K + and ATP Increases in the Extracellular Space. Front Cell Neurosci 2017; 11:349. [PMID: 29163059 PMCID: PMC5675856 DOI: 10.3389/fncel.2017.00349] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [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: 09/05/2017] [Accepted: 10/20/2017] [Indexed: 01/24/2023] Open
Abstract
During brain ischemia, intense energy deficiency induces a complex succession of events including pump failure, acidosis and exacerbated glutamate release. In the cerebellum, glutamate is the principal mediator of Purkinje neuron anoxic depolarization during episodes of oxygen and glucose deprivation (OGD). Here, the impact of OGD is studied in Bergmann glia, specialized astrocytes closely associated to Purkinje neurons. Patch clamp experiments reveal that during OGD Bergmann glial cells develop a large depolarizing current that is not mediated by glutamate and purinergic receptors but is mainly due to the accumulation of K+ in the extracellular space. Furthermore, we also found that increases in the intracellular Ca2+ concentration appear in Bergmann glia processes several minutes following OGD. These elevations require, in an early phase, Ca2+ mobilization from internal stores via P2Y receptor activation, and, over longer periods, Ca2+ entry through store-operated calcium channels. Our results suggest that increases of K+ and ATP concentrations in the extracellular space are primordial mediators of the OGD effects on Bergmann glia. In the cerebellum, glial responses to energy deprivation-triggering events are therefore highly likely to follow largely distinct rules from those of their neuronal counterparts.
Collapse
Affiliation(s)
- Romain Helleringer
- Pharmacology and Biochemistry of the Synapse, Institut des Neurosciences Paris-Saclay, Université Paris-Saclay, Université Paris-Sud, CNRS, UMR 9197, Orsay, France
| | - Oana Chever
- Neuroglial Interactions in Cerebral Physiopathology, Center for Interdisciplinary Research in Biology, Collège de France, CNRS, UMR 7241, INSERM U1050, Labex Memolife, PSL Research University Paris, Paris, France
| | - Hervé Daniel
- Pharmacology and Biochemistry of the Synapse, Institut des Neurosciences Paris-Saclay, Université Paris-Saclay, Université Paris-Sud, CNRS, UMR 9197, Orsay, France
| | - Micaela Galante
- Pharmacology and Biochemistry of the Synapse, Institut des Neurosciences Paris-Saclay, Université Paris-Saclay, Université Paris-Sud, CNRS, UMR 9197, Orsay, France
| |
Collapse
|
9
|
Affiliation(s)
- Oana Chever
- Neuroglial interactions in cerebral physiopathology, Center for Interdisciplinary Research in Biology, Collège de France, CNRS UMR 7241, Inserm U1050, Labex Memolife, PSL Research University, 11, place Marcelin Berthelot, 75005 Paris, France
| | - Elena Dossi
- Neuroglial interactions in cerebral physiopathology, Center for Interdisciplinary Research in Biology, Collège de France, CNRS UMR 7241, Inserm U1050, Labex Memolife, PSL Research University, 11, place Marcelin Berthelot, 75005 Paris, France
| | - Nathalie Rouach
- Neuroglial interactions in cerebral physiopathology, Center for Interdisciplinary Research in Biology, Collège de France, CNRS UMR 7241, Inserm U1050, Labex Memolife, PSL Research University, 11, place Marcelin Berthelot, 75005 Paris, France
| |
Collapse
|
10
|
|
11
|
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
|
12
|
Abstract
Connexin hemichannels are single membrane channels which have been traditionally thought to work in pairs to form gap junction channels across two opposing cells. In astrocytes, gap junction channels allow direct intercellular communication and greatly facilitate the transmission of signals. Recently, there has been growing evidence demonstrating that connexin hemichannels, as well as pannexin channels, on their own are open in various conditions. They allow bidirectional flow of ions and signaling molecules and act as release sites for transmitters like ATP and glutamate into the extracellular space. While much attention has focused on the function of connexin hemichannels and pannexons during pathological situations like epilepsy, inflammation, neurodegeneration or ischemia, their potential roles in physiology is often ignored. In order to fully understand the dynamic properties and roles of connexin hemichannels and pannexons in the brain, it is essential to decipher whether they also have some physiological functions and contribute to normal cerebral processes. Here, we present recent studies in the CNS suggesting emerging physiological functions of connexin hemichannels and pannexons in normal neuronal activity and behavior. We also discuss how these pioneer studies pave the way for future research to extend the physiological relevance of connexons and pannexons, and some fundamental issues yet to be addressed.
Collapse
Affiliation(s)
- Giselle Cheung
- Neuroglial Interactions in Cerebral Physiopathology, Center for Interdisciplinary Research in Biology, Collège de France, CNRS UMR 7241, INSERM U1050, Labex Memolife, PSL Research University Paris, France
| | - Oana Chever
- Neuroglial Interactions in Cerebral Physiopathology, Center for Interdisciplinary Research in Biology, Collège de France, CNRS UMR 7241, INSERM U1050, Labex Memolife, PSL Research University Paris, France
| | - Nathalie Rouach
- Neuroglial Interactions in Cerebral Physiopathology, Center for Interdisciplinary Research in Biology, Collège de France, CNRS UMR 7241, INSERM U1050, Labex Memolife, PSL Research University Paris, France
| |
Collapse
|
13
|
Dallérac G, Chever O, Rouach N. How do astrocytes shape synaptic transmission? Insights from electrophysiology. Front Cell Neurosci 2013; 7:159. [PMID: 24101894 PMCID: PMC3787198 DOI: 10.3389/fncel.2013.00159] [Citation(s) in RCA: 108] [Impact Index Per Article: 9.8] [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: 04/17/2013] [Accepted: 09/02/2013] [Indexed: 02/01/2023] Open
Abstract
A major breakthrough in neuroscience has been the realization in the last decades that the dogmatic view of astroglial cells as being merely fostering and buffering elements of the nervous system is simplistic. A wealth of investigations now shows that astrocytes actually participate in the control of synaptic transmission in an active manner. This was first hinted by the intimate contacts glial processes make with neurons, particularly at the synaptic level, and evidenced using electrophysiological and calcium imaging techniques. Calcium imaging has provided critical evidence demonstrating that astrocytic regulation of synaptic efficacy is not a passive phenomenon. However, given that cellular activation is not only represented by calcium signaling, it is also crucial to assess concomitant mechanisms. We and others have used electrophysiological techniques to simultaneously record neuronal and astrocytic activity, thus enabling the study of multiple ionic currents and in depth investigation of neuro-glial dialogues. In the current review, we focus on the input such approach has provided in the understanding of astrocyte-neuron interactions underlying control of synaptic efficacy.
Collapse
Affiliation(s)
- Glenn Dallérac
- Neuroglial Interactions in Cerebral Physiopathology, Center for Interdisciplinary Research in Biology, CNRS UMR 7241, INSERM U1050, Collège de France Paris, France
| | | | | |
Collapse
|
14
|
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
|
15
|
Abstract
In order to produce its desired effect, anaesthesia acts upon neuronal elements by modifying membrane conductances and transmitter interactions. The effect of higher doses of isoflurane, widely used in clinical settings, on the permeability of the blood-brain barrier (BBB) is meanwhile ignored. In this study we investigated the integrity of the BBB during various levels of isoflurane anaesthesia (1% and 3%) in cats by monitoring the extravasation of Evans blue. Simultaneously we measured the electroencephalogram (EEG), with particular emphasis on its direct current (DC) component. High doses of anaesthetic (3%) broke down the BBB in the cortex and thalamus, while milder doses (1%) only opened the BBB in the thalamus. The fluorescent signal of Evans blue was visible over an extravascular length of 23 mum in the cortex and 25 mum in the thalamus, similar to the diffusion of the same dye when the BBB was disrupted with mannitol. The opening of the BBB was associated with (i) a positive DC shift in the EEG measured on the scalp and (ii) an evaluated increase in cerebral volume of 2-2.8%. The opening of the BBB by high doses of isoflurane brings into discussion hitherto unexplored effects of anaesthesia on the brain. The electrophysiological correlate provided by the DC component of the EEG constitutes a promising option for the assessment of the BBB integrity during human anaesthesia.
Collapse
Affiliation(s)
- Samuel Tétrault
- Centre de recherche de l'Université Laval Robert-Giffard, Quebec, Canada
| | | | | | | |
Collapse
|