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Ringuette D, EbrahimAmini A, Sangphosuk W, Aquilino MS, Carroll G, Ashley M, Bazzigaluppi P, Dufour S, Droguerre M, Stefanovic B, Levi O, Charveriat M, Monnier PP, Carlen PL. Spreading depolarization suppression from inter-astrocytic gap junction blockade assessed with multimodal imaging and a novel wavefront detection scheme. Neurotherapeutics 2024; 21:e00298. [PMID: 38241157 PMCID: PMC10903093 DOI: 10.1016/j.neurot.2023.10.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2023] [Accepted: 10/07/2023] [Indexed: 01/21/2024] Open
Abstract
Spreading depolarizations (SDs) are an enigmatic and ubiquitous co-morbidity of neural dysfunction. SDs are propagating waves of local field depolarization and increased extracellular potassium. They increase the metabolic demand on brain tissue, resulting in changes in tissue blood flow, and are associated with adverse neurological consequences including stroke, epilepsy, neurotrauma, and migraine. Their occurrence is associated with poor patient prognosis through mechanisms which are only partially understood. Here we show in vivo that two (structurally dissimilar) drugs, which suppress astroglial gap junctional communication, can acutely suppress SDs. We found that mefloquine hydrochloride (MQH), administered IP, slowed the propagation of the SD potassium waveform and intermittently led to its suppression. The hemodynamic response was similarly delayed and intermittently suppressed. Furthermore, in instances where SD led to transient tissue swelling, MQH reduced observable tissue displacement. Administration of meclofenamic acid (MFA) IP was found to reduce blood flow, both proximal and distal, to the site of SD induction, preceding a large reduction in the amplitude of the SD-associated potassium wave. We introduce a novel image processing scheme for SD wavefront localization under low-contrast imaging conditions permitting full-field wavefront velocity mapping and wavefront parametrization. We found that MQH administration delayed SD wavefront's optical correlates. These two clinically used drugs, both gap junctional blockers found to distinctly suppress SDs, may be of therapeutic benefit in the various brain disorders associated with recurrent SDs.
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Affiliation(s)
- Dene Ringuette
- Department of Physiology, Faculty of Medicine, University of Toronto, 1 King's College Circle, Toronto, Ontario M5S 1A8, Canada; Division of Genetics and Development, Krembil Research Institute, 60 Leonard Ave., Toronto, Ontario M5T 2S8, Canada; Krembil Neuroscience, Krembil Research Institute, 60 Leonard Ave., Toronto, Ontario M5T 2S8, Canada.
| | - Azin EbrahimAmini
- Krembil Neuroscience, Krembil Research Institute, 60 Leonard Ave., Toronto, Ontario M5T 2S8, Canada; The Institute Biomedical Engineering, University of Toronto, 164 College St., Toronto, Ontario M5S 3G9, Canada
| | - Weerawong Sangphosuk
- Krembil Neuroscience, Krembil Research Institute, 60 Leonard Ave., Toronto, Ontario M5T 2S8, Canada
| | - Mark S Aquilino
- The Institute Biomedical Engineering, University of Toronto, 164 College St., Toronto, Ontario M5S 3G9, Canada
| | - Gwennyth Carroll
- The Institute Biomedical Engineering, University of Toronto, 164 College St., Toronto, Ontario M5S 3G9, Canada
| | - Max Ashley
- Krembil Neuroscience, Krembil Research Institute, 60 Leonard Ave., Toronto, Ontario M5T 2S8, Canada
| | - Paolo Bazzigaluppi
- Sunnybrook Health Sciences Center, 2075 Bayview Ave., Toronto, Ontario M4N 3M5, Canada
| | - Suzie Dufour
- The Institute Biomedical Engineering, University of Toronto, 164 College St., Toronto, Ontario M5S 3G9, Canada
| | | | - Bojana Stefanovic
- Department of Medical Biophysics, University of Toronto, 610 University Ave., Toronto, Ontario M5G 2M9, Canada; Sunnybrook Health Sciences Center, 2075 Bayview Ave., Toronto, Ontario M4N 3M5, Canada
| | - Ofer Levi
- The Institute Biomedical Engineering, University of Toronto, 164 College St., Toronto, Ontario M5S 3G9, Canada; The Edward S. Rogers Sr. Department of Electrical and Computer Engineering, University of Toronto, 10 King's College Rd., Toronto, Ontario M5S 3G4, Canada
| | | | - Philippe P Monnier
- Department of Physiology, Faculty of Medicine, University of Toronto, 1 King's College Circle, Toronto, Ontario M5S 1A8, Canada; Division of Genetics and Development, Krembil Research Institute, 60 Leonard Ave., Toronto, Ontario M5T 2S8, Canada; Department of Ophthalmology & Vision Science, Faculty of Medicine, University of Toronto, 340 College St., Toronto, Ontario M5T 3A9, Canada
| | - Peter L Carlen
- Department of Physiology, Faculty of Medicine, University of Toronto, 1 King's College Circle, Toronto, Ontario M5S 1A8, Canada; Division of Genetics and Development, Krembil Research Institute, 60 Leonard Ave., Toronto, Ontario M5T 2S8, Canada; Krembil Neuroscience, Krembil Research Institute, 60 Leonard Ave., Toronto, Ontario M5T 2S8, Canada; The Institute Biomedical Engineering, University of Toronto, 164 College St., Toronto, Ontario M5S 3G9, Canada
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Pereira MJ, Ayana R, Holt MG, Arckens L. Chemogenetic manipulation of astrocyte activity at the synapse- a gateway to manage brain disease. Front Cell Dev Biol 2023; 11:1193130. [PMID: 37534103 PMCID: PMC10393042 DOI: 10.3389/fcell.2023.1193130] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Accepted: 06/14/2023] [Indexed: 08/04/2023] Open
Abstract
Astrocytes are the major glial cell type in the central nervous system (CNS). Initially regarded as supportive cells, it is now recognized that this highly heterogeneous cell population is an indispensable modulator of brain development and function. Astrocytes secrete neuroactive molecules that regulate synapse formation and maturation. They also express hundreds of G protein-coupled receptors (GPCRs) that, once activated by neurotransmitters, trigger intracellular signalling pathways that can trigger the release of gliotransmitters which, in turn, modulate synaptic transmission and neuroplasticity. Considering this, it is not surprising that astrocytic dysfunction, leading to synaptic impairment, is consistently described as a factor in brain diseases, whether they emerge early or late in life due to genetic or environmental factors. Here, we provide an overview of the literature showing that activation of genetically engineered GPCRs, known as Designer Receptors Exclusively Activated by Designer Drugs (DREADDs), to specifically modulate astrocyte activity partially mimics endogenous signalling pathways in astrocytes and improves neuronal function and behavior in normal animals and disease models. Therefore, we propose that expressing these genetically engineered GPCRs in astrocytes could be a promising strategy to explore (new) signalling pathways which can be used to manage brain disorders. The precise molecular, functional and behavioral effects of this type of manipulation, however, differ depending on the DREADD receptor used, targeted brain region and timing of the intervention, between healthy and disease conditions. This is likely a reflection of regional and disease/disease progression-associated astrocyte heterogeneity. Therefore, a thorough investigation of the effects of such astrocyte manipulation(s) must be conducted considering the specific cellular and molecular environment characteristic of each disease and disease stage before this has therapeutic applicability.
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Affiliation(s)
- Maria João Pereira
- Department of Biology, Laboratory of Neuroplasticity and Neuroproteomics, KU Leuven, Leuven, Belgium
- KU Leuven Brain Institute, Leuven, Belgium
| | - Rajagopal Ayana
- Department of Biology, Laboratory of Neuroplasticity and Neuroproteomics, KU Leuven, Leuven, Belgium
- KU Leuven Brain Institute, Leuven, Belgium
| | - Matthew G. Holt
- Instituto de Investigação e Inovação em Saúde (i3S), Laboratory of Synapse Biology, Universidade do Porto, Porto, Portugal
| | - Lutgarde Arckens
- Department of Biology, Laboratory of Neuroplasticity and Neuroproteomics, KU Leuven, Leuven, Belgium
- KU Leuven Brain Institute, Leuven, Belgium
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3
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Dong R, Lv P, Han Y, Jiang L, Wang Z, Peng L, Ma Z, Xia T, Zhang B, Gu X. Enhancement of astrocytic gap junctions Connexin43 coupling can improve long-term isoflurane anesthesia-mediated brain network abnormalities and cognitive impairment. CNS Neurosci Ther 2022; 28:2281-2297. [PMID: 36153812 PMCID: PMC9627365 DOI: 10.1111/cns.13974] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Revised: 08/31/2022] [Accepted: 09/03/2022] [Indexed: 02/06/2023] Open
Abstract
AIM Astrocytes are connected by gap junctions Connexin43 (GJs-Cx43) forming an extensive intercellular network and maintain brain homeostasis. Perioperative neurocognitive disorder (PND) occurs frequently after anesthesia/surgery and worsens patient outcome, but the neural circuit mechanisms remain unclear. This study aimed to determine the effects of the GJs-Cx43-mediated astrocytic network on PND and ascertain the underlying neural circuit mechanism. METHODS Male C57BL/6 mice were treated with long-term isoflurane exposure to construct a mouse model of PND. We also exposed primary mouse astrocytes to long-term isoflurane exposure to simulate the conditions of in vivo cognitive dysfunction. Behavioral tests were performed using the Y-maze and fear conditioning (FC) tests. Manganese-enhanced magnetic resonance imaging (MEMRI) and resting-state functional magnetic resonance imaging (rs-fMRI) were used to investigate brain activity and functional connectivity. Western blot and flow cytometry analysis were used to assess protein expression. RESULTS Reconfiguring the astrocytic network by increasing GJs-Cx43 expression can modulate 22 subregions affected by PND in three ways: reversed activation, reversed inhibition, and intensified activation. The brain functional connectivity analysis further suggests that PND is a brain network disorder that includes sleep-wake rhythm-related brain regions, contextual and fear memory-related subregions, the hippocampal-amygdala circuit, the septo-hippocampal circuit, and the entorhinal-hippocampal circuit. Notably, remodeling the astrocytic network by upregulation of GJs-Cx43 can partially reverse the abnormalities in the above circuits. Pathophysiological degeneration in hippocampus is one of the primary hallmarks of PND pathology, and long-term isoflurane anesthesia contributes to oxidative stress and neuroinflammation in the hippocampus. However, promoting the formation of GJs-Cx43 ameliorated cognitive dysfunction induced by long-term isoflurane anesthesia through the attenuation of oxidative stress in hippocampus. CONCLUSION Enhancing GJs-Cx43 coupling can improve brain network abnormalities and cognitive impairment induced by long-term isoflurane anesthesia, its mechanisms might be associated with the regulation of oxidative stress and neuroinflammation.
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Affiliation(s)
- Rui Dong
- Department of AnesthesiologyThe Affiliated Drum Tower Hospital of Nanjing University Medical SchoolNanjingChina
| | - Pin Lv
- Department of RadiologyThe Affiliated Drum Tower Hospital of Nanjing University Medical SchoolNanjingChina
| | - Yuqiang Han
- Department of AnesthesiologyThe Affiliated Drum Tower Hospital of Nanjing University Medical SchoolNanjingChina
| | - Linhao Jiang
- Department of AnesthesiologyThe Affiliated Drum Tower Hospital of Nanjing University Medical SchoolNanjingChina
| | - Zimo Wang
- Department of AnesthesiologyThe Affiliated Drum Tower Hospital of Nanjing University Medical SchoolNanjingChina
| | - Liangyu Peng
- Department of AnesthesiologyThe Affiliated Drum Tower Hospital of Nanjing University Medical SchoolNanjingChina
| | - Zhengliang Ma
- Department of AnesthesiologyThe Affiliated Drum Tower Hospital of Nanjing University Medical SchoolNanjingChina
| | - Tianjiao Xia
- Medical SchoolNanjing UniversityNanjingChina,Jiangsu Key Laboratory of Molecular MedicineNanjingChina
| | - Bing Zhang
- Department of RadiologyThe Affiliated Drum Tower Hospital of Nanjing University Medical SchoolNanjingChina,Jiangsu Key Laboratory of Molecular MedicineNanjingChina,Institute of Medical Imaging and Artificial IntelligenceNanjing UniversityNanjingChina,Institute of Brain ScienceNanjing UniversityNanjingChina
| | - Xiaoping Gu
- Department of AnesthesiologyThe Affiliated Drum Tower Hospital of Nanjing University Medical SchoolNanjingChina
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Modeling and Targeting Neuroglial Interactions with Human Pluripotent Stem Cell Models. Int J Mol Sci 2022; 23:ijms23031684. [PMID: 35163606 PMCID: PMC8836094 DOI: 10.3390/ijms23031684] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Revised: 01/26/2022] [Accepted: 01/30/2022] [Indexed: 02/05/2023] Open
Abstract
Generation of relevant and robust models for neurological disorders is of main importance for both target identification and drug discovery. The non-cell autonomous effects of glial cells on neurons have been described in a broad range of neurodegenerative and neurodevelopmental disorders, pointing to neuroglial interactions as novel alternative targets for therapeutics development. Interestingly, the recent breakthrough discovery of human induced pluripotent stem cells (hiPSCs) has opened a new road for studying neurological and neurodevelopmental disorders “in a dish”. Here, we provide an overview of the generation and modeling of both neuronal and glial cells from human iPSCs and a brief synthesis of recent work investigating neuroglial interactions using hiPSCs in a pathophysiological context.
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5
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Letellier B, Kremer M, Becker LJ, Andry V, Goumon Y, Leboulleux Q, Hener P, Inquimbert P, Couqueberg N, Waltisperger E, Yalcin I, Mouthon F, Droguerre M, Charvériat M, Barrot M. Action of mefloquine/amitriptyline THN101 combination on neuropathic mechanical hypersensitivity in mice. Pain 2021; 162:2841-2853. [PMID: 33769363 PMCID: PMC8600545 DOI: 10.1097/j.pain.0000000000002276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Revised: 02/19/2021] [Accepted: 02/22/2021] [Indexed: 11/25/2022]
Abstract
ABSTRACT Tricyclic antidepressants that inhibit serotonin and noradrenaline reuptake, such as amitriptyline, are among the first-line treatments for neuropathic pain, which is caused by a lesion or disease affecting the somatosensory nervous system. These treatments are, however, partially efficient to alleviate neuropathic pain symptoms, and better treatments are still highly required. Interactions between neurons and glial cells participate in neuropathic pain processes, and importantly, connexins-transmembrane proteins involved in cell-cell communication-contribute to these interactions. In a neuropathic pain model in rats, mefloquine, a connexin inhibitor, has been shown to potentiate the antihyperalgesic effect of amitriptyline, a widely used antidepressant. In this study, we further investigated this improvement of amitriptyline action by mefloquine, using the cuff model of neuropathic pain in mice. We first observed that oral mefloquine co-treatment prolonged the effect of amitriptyline on mechanical hypersensitivity by 12 hours after administration. In addition, we showed that this potentiation was not due to pharmacokinetic interactions between the 2 drugs. Besides, lesional and pharmacological approaches showed that the prolonged effect was induced through noradrenergic descending pathways and the recruitment of α2 adrenoceptors. Another connexin blocker, carbenoxolone, also improved amitriptyline action. Additional in vitro studies suggested that mefloquine may also directly act on serotonin transporters and on adenosine A1 and A2A receptors, but drugs acting on these other targets failed to amplify amitriptyline action. Together, our data indicate that pharmacological blockade of connexins potentiates the therapeutic effect of amitriptyline in neuropathic pain.
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Affiliation(s)
- Baptiste Letellier
- Centre National de la Recherche Scientifique, Université de Strasbourg, Institut des Neurosciences Cellulaires et Intégratives, Strasbourg, France
- Theranexus, Lyon, France
| | - Mélanie Kremer
- Centre National de la Recherche Scientifique, Université de Strasbourg, Institut des Neurosciences Cellulaires et Intégratives, Strasbourg, France
| | - Léa J. Becker
- Centre National de la Recherche Scientifique, Université de Strasbourg, Institut des Neurosciences Cellulaires et Intégratives, Strasbourg, France
| | - Virginie Andry
- Centre National de la Recherche Scientifique, Université de Strasbourg, Institut des Neurosciences Cellulaires et Intégratives, Strasbourg, France
| | - Yannick Goumon
- Centre National de la Recherche Scientifique, Université de Strasbourg, Institut des Neurosciences Cellulaires et Intégratives, Strasbourg, France
| | - Quentin Leboulleux
- Centre National de la Recherche Scientifique, Université de Strasbourg, Institut des Neurosciences Cellulaires et Intégratives, Strasbourg, France
| | - Pierre Hener
- Centre National de la Recherche Scientifique, Université de Strasbourg, Institut des Neurosciences Cellulaires et Intégratives, Strasbourg, France
| | - Perrine Inquimbert
- Centre National de la Recherche Scientifique, Université de Strasbourg, Institut des Neurosciences Cellulaires et Intégratives, Strasbourg, France
| | - Nolwenn Couqueberg
- Centre National de la Recherche Scientifique, Université de Strasbourg, Institut des Neurosciences Cellulaires et Intégratives, Strasbourg, France
| | - Elisabeth Waltisperger
- Centre National de la Recherche Scientifique, Université de Strasbourg, Institut des Neurosciences Cellulaires et Intégratives, Strasbourg, France
| | - Ipek Yalcin
- Centre National de la Recherche Scientifique, Université de Strasbourg, Institut des Neurosciences Cellulaires et Intégratives, Strasbourg, France
| | | | | | | | - Michel Barrot
- Centre National de la Recherche Scientifique, Université de Strasbourg, Institut des Neurosciences Cellulaires et Intégratives, Strasbourg, France
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Potential of Multiscale Astrocyte Imaging for Revealing Mechanisms Underlying Neurodevelopmental Disorders. Int J Mol Sci 2021; 22:ijms221910312. [PMID: 34638653 PMCID: PMC8508625 DOI: 10.3390/ijms221910312] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2021] [Revised: 09/21/2021] [Accepted: 09/22/2021] [Indexed: 01/18/2023] Open
Abstract
Astrocytes provide trophic and metabolic support to neurons and modulate circuit formation during development. In addition, astrocytes help maintain neuronal homeostasis through neurovascular coupling, blood-brain barrier maintenance, clearance of metabolites and nonfunctional proteins via the glymphatic system, extracellular potassium buffering, and regulation of synaptic activity. Thus, astrocyte dysfunction may contribute to a myriad of neurological disorders. Indeed, astrocyte dysfunction during development has been implicated in Rett disease, Alexander's disease, epilepsy, and autism, among other disorders. Numerous disease model mice have been established to investigate these diseases, but important preclinical findings on etiology and pathophysiology have not translated into clinical interventions. A multidisciplinary approach is required to elucidate the mechanism of these diseases because astrocyte dysfunction can result in altered neuronal connectivity, morphology, and activity. Recent progress in neuroimaging techniques has enabled noninvasive investigations of brain structure and function at multiple spatiotemporal scales, and these technologies are expected to facilitate the translation of preclinical findings to clinical studies and ultimately to clinical trials. Here, we review recent progress on astrocyte contributions to neurodevelopmental and neuropsychiatric disorders revealed using novel imaging techniques, from microscopy scale to mesoscopic scale.
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Decreased connexin43 expression in the hippocampus is related to the antidepressant effect of amitriptyline in neuropathic pain mice. Biochem Biophys Res Commun 2021; 566:141-147. [PMID: 34126344 DOI: 10.1016/j.bbrc.2021.06.020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Accepted: 06/04/2021] [Indexed: 12/17/2022]
Abstract
Downregulation of astrocytic connexin43 (Cx43) has been observed in several brain regions in rodents and patients with depression. However, its specific role in this effect remains unknown. Moreover, chronic pain can induce depressive disorders. Therefore, the current study examined the relationship between Cx43 expression and depressive-like behavior in a neuropathic pain model. Neuropathic pain was induced by spared nerve injury (SNI) in mice. Depressive-like behavior was evaluated using the forced swim test. Expression of Cx43 in the hippocampus was evaluated using Western blotting and real-time PCR. SNI downregulated Cx43 protein in the contralateral hippocampus of mice, whereas expression of hippocampal Cx43 mRNA was not altered following SNI. Although SNI mice showed longer immobility time compared with sham mice during the forced swim test, duration of depressive-like behavior was not correlated with the expression of Cx43 in the hippocampus of SNI mice. Repeated intraperitoneal administration of amitriptyline ameliorated SNI-induced depressive-like behavior. Furthermore, the antidepressant effect of amitriptyline was correlated with decreased hippocampal Cx43 expression in SNI mice. The current findings suggest that the alteration of Cx43 expression in the hippocampus may not be involved in the induction of depressive disorder but may influence the efficacy of antidepressants. Therefore, the level of Cx43 expression in the hippocampus could be a key parameter to evaluate individual differences in antidepressant effects in patients with depressive disorder.
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Stephan J, Eitelmann S, Zhou M. Approaches to Study Gap Junctional Coupling. Front Cell Neurosci 2021; 15:640406. [PMID: 33776652 PMCID: PMC7987795 DOI: 10.3389/fncel.2021.640406] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Accepted: 02/03/2021] [Indexed: 12/17/2022] Open
Abstract
Astrocytes and oligodendrocytes are main players in the brain to ensure ion and neurotransmitter homeostasis, metabolic supply, and fast action potential propagation in axons. These functions are fostered by the formation of large syncytia in which mainly astrocytes and oligodendrocytes are directly coupled. Panglial networks constitute on connexin-based gap junctions in the membranes of neighboring cells that allow the passage of ions, metabolites, and currents. However, these networks are not uniform but exhibit a brain region-dependent heterogeneous connectivity influencing electrical communication and intercellular ion spread. Here, we describe different approaches to analyze gap junctional communication in acute tissue slices that can be implemented easily in most electrophysiology and imaging laboratories. These approaches include paired recordings, determination of syncytial isopotentiality, tracer coupling followed by analysis of network topography, and wide field imaging of ion sensitive dyes. These approaches are capable to reveal cellular heterogeneity causing electrical isolation of functional circuits, reduced ion-transfer between different cell types, and anisotropy of tracer coupling. With a selective or combinatory use of these methods, the results will shed light on cellular properties of glial cells and their contribution to neuronal function.
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Affiliation(s)
- Jonathan Stephan
- Institute of Neurobiology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Sara Eitelmann
- Institute of Neurobiology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Min Zhou
- Department of Neuroscience, Wexner Medical Center, Ohio State University, Columbus, OH, United States
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9
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Charvériat M, Mouthon F, Rein W, Verkhratsky A. Connexins as therapeutic targets in neurological and neuropsychiatric disorders. Biochim Biophys Acta Mol Basis Dis 2021; 1867:166098. [PMID: 33545299 DOI: 10.1016/j.bbadis.2021.166098] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Revised: 01/06/2021] [Accepted: 01/19/2021] [Indexed: 12/16/2022]
Abstract
Astrocytes represent the reticular part of the central nervous system; gap junctions formed by connexins Cx43, Cx30- and Cx26 provide for homocellular astrocyte-astrocyte coupling, whereas connexins Cx30, Cx32, Cx43, and Cx47 connect astrocytes and oligodendrocytes. Astroglial networks are anatomically and functionally segregated being homologous to neuronal ensembles. Connexons, gap junctions and hemichannels (unpaired connexons) are affected in various neuropathologies from neuropsychiatric to neurodegenerative diseases. Manipulation of astrocytic connexins modulates the size and outreach of astroglial syncytia thus affecting astroglial homeostatic support. Modulation of astrocytic connexin significantly modifies pharmacological profile of many CNS drugs, which represents an innovative therapeutic approach for CNS disorders; this approach is now actively tested in pre-clinical and clinical studies. Wide combination of connexin modulators with CNS drugs open new promising perspectives for fundamental studies and therapeutic strategies.
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Affiliation(s)
| | | | | | - A Verkhratsky
- Faculty of Biology, Medicine and Health, The University of Manchester, Manchester M13 9PT, UK; Achucarro Centre for Neuroscience, IKERBASQUE, Basque Foundation for Science, 48011 Bilbao, Spain
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Charvériat M, Guiard BP. Serotonergic neurons in the treatment of mood disorders: The dialogue with astrocytes. PROGRESS IN BRAIN RESEARCH 2021; 259:197-228. [PMID: 33541677 DOI: 10.1016/bs.pbr.2021.01.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Astrocytes were traditionally regarded as cells important to neuronal activity, providing both metabolic and structural supports. Recent evidence suggests that they may also play a crucial role in the control of higher brain functions. In keeping with this hypothesis, it is now well accepted that astrocytes contribute to stress but also react to antidepressant drugs as they express serotonergic transporters and receptors. However, the downstream mechanisms leading to the fine-tuned regulation of mood are still unknown. This chapter pays attention to the role of astrocytes in the regulation of emotional behavior and related serotonergic neurotransmission. In particular, it gives a current state of the clinical and preclinical evidence showing that astrocytes respond to environmental conditions and antidepressant drugs through the release of gliotransmitters and neurotrophic factors which in turn, influence serotonergic tone in discrete brain areas. This state-of-the-art review aims at demonstrating the remarkable potential for novel therapeutic antidepressant strategies targeting these glial cells.
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Affiliation(s)
| | - Bruno P Guiard
- Centre de Recherches sur la Cognition Animale, Centre de Biologie Intégrative, Université de Toulouse, CNRS, Toulouse, France.
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11
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Soleilhac E, Comte M, da Costa A, Barette C, Picoli C, Mortier M, Aubry L, Mouthon F, Fauvarque MO, Charvériat M. Quantitative Automated Assays in Living Cells to Screen for Inhibitors of Hemichannel Function. SLAS DISCOVERY 2020; 26:420-427. [PMID: 32914684 DOI: 10.1177/2472555220954388] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
In vertebrates, intercellular communication is largely mediated by connexins (Cx), a family of structurally related transmembrane proteins that assemble to form hemichannels (HCs) at the plasma membrane. HCs are upregulated in different brain disorders and represent innovative therapeutic targets. Identifying modulators of Cx-based HCs is of great interest to better understand their function and define new treatments. In this study, we developed automated versions of two different cell-based assays to identify new pharmacological modulators of Cx43-HCs. As HCs remain mostly closed under physiological conditions in cell culture, depletion of extracellular Ca2+ was used to increase the probability of opening of HCs. The first assay follows the incorporation of a fluorescent dye, Yo-Pro, by real-time imaging, while the second is based on the quenching of a fluorescent protein, YFPQL, by iodide after iodide uptake. These assays were then used to screen a collection of 2242 approved drugs and compounds under development. This study led to the identification of 11 candidate hits blocking Cx43-HC, active in the two assays, with 5 drugs active on HC but not on gap junction (GJ) activities. To our knowledge, this is the first screening on HC activity and our results suggest the potential of a new use of already approved drugs in central nervous system disorders with HC impairments.
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Affiliation(s)
| | - Marjorie Comte
- University Grenoble Alpes, CEA, Inserm, IRIG, BGE, Grenoble, France
| | | | - Caroline Barette
- University Grenoble Alpes, CEA, Inserm, IRIG, BGE, Grenoble, France
| | | | - Magda Mortier
- University Grenoble Alpes, CEA, Inserm, IRIG, BGE, Grenoble, France
| | - Laurence Aubry
- University Grenoble Alpes, CEA, Inserm, IRIG, BGE, Grenoble, France
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12
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Vidal B, Droguerre M, Valdebenito M, Zimmer L, Hamon M, Mouthon F, Charvériat M. Pharmaco-fUS for Characterizing Drugs for Alzheimer's Disease - The Case of THN201, a Drug Combination of Donepezil Plus Mefloquine. Front Neurosci 2020; 14:835. [PMID: 32903470 PMCID: PMC7437134 DOI: 10.3389/fnins.2020.00835] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Accepted: 07/17/2020] [Indexed: 01/29/2023] Open
Abstract
Donepezil is a potent acetylcholinesterase inhibitor, largely used worldwide to alleviate cognitive symptoms in Alzheimer’s disease (AD). Beyond the widely described neuronal impact of donepezil, it was recently shown that targeting connexins, the proteins involved in astrocyte network organization, potentiates donepezil efficacy profile using behavioral tests in AD rodent models. We herein present data demonstrating the potential of functional ultrasound imaging to monitor cerebral activity changes after pharmacological challenge in mice. As an example, we showed that although administration of donepezil or mefloquine alone at low dose had only very limited effects on the signal compared to the baseline, their combination produced marked hemodynamic effects in the hippocampus, in line with previously published behavioral data demonstrating a synergic interaction between both drugs. Thus, the present study provides new perspectives, (i) through the use of pharmaco-fUS, a new non-clinical imaging modality, to move forward drug discovery in AD and (ii) by the profiling of two drug treatments on brain dynamics, one used in AD: donepezil, and the other in development: donepezil combined with mefloquine (THN201) as a modulator of astrocyte network.
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Affiliation(s)
- Benjamin Vidal
- Theranexus, Lyon, France.,Lyon Neuroscience Research Center, Université de Lyon, INSERM, CNRS, Bron, France
| | | | | | - Luc Zimmer
- Lyon Neuroscience Research Center, Université de Lyon, INSERM, CNRS, Bron, France.,CERMEP-Imagerie du Vivant, Bron, France.,Hospices Civils de Lyon, Lyon, France
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13
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Droguerre M, Duchêne A, Picoli C, Portal B, Lejards C, Guiard BP, Meunier J, Villard V, Déglon N, Hamon M, Mouthon F, Charvériat M. Efficacy of THN201, a Combination of Donepezil and Mefloquine, to Reverse Neurocognitive Deficits in Alzheimer's Disease. Front Neurosci 2020; 14:563. [PMID: 32612499 PMCID: PMC7309601 DOI: 10.3389/fnins.2020.00563] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Accepted: 05/07/2020] [Indexed: 01/15/2023] Open
Abstract
Donepezil (DPZ) is an acetylcholinesterase inhibitor used in Alzheimer’s disease to restore cognitive functions but is endowed with limited efficacy. Recent studies pointed out the implication of astroglial networks in cognitive processes, notably via astrocyte connexins (Cxs), proteins involved in gap junction intercellular communications. Hence, we investigated the impact on cognition of pharmacological or genetic modulations of those astrocyte Cxs during DPZ challenge in two rodent models of Alzheimer’s disease–like memory deficits. We demonstrated that the Cx modulator mefloquine (MEF) significantly enhanced the procognitive effect of DPZ in both models. In parallel, we determined that MEF potentiated DPZ-induced release of acetylcholine in hippocampus. Finally, local genetic silencing of astrocyte Cxs in the hippocampus was also found to enhance the procognitive effect of DPZ, pointing out the importance of Cx-dependent astrocyte networks in memory processes.
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Affiliation(s)
| | | | | | - Benjamin Portal
- Centre de Recherches sur la Cognition Animale (CRCA), Centre de Biologie Intégrative (CBI), CNRS, UPS, Université de Toulouse, Toulouse, France
| | - Camille Lejards
- Centre de Recherches sur la Cognition Animale (CRCA), Centre de Biologie Intégrative (CBI), CNRS, UPS, Université de Toulouse, Toulouse, France
| | - Bruno P Guiard
- Centre de Recherches sur la Cognition Animale (CRCA), Centre de Biologie Intégrative (CBI), CNRS, UPS, Université de Toulouse, Toulouse, France
| | | | | | - Nicole Déglon
- Laboratory of Neurotherapies and NeuroModulation, Neuroscience Research Center (CRN), University of Lausanne, Lausanne, Switzerland.,Laboratory of Neurotherapies and NeuroModulation, Department of Clinical Neuroscience (DNC), Lausanne University Hospital (CHUV), Lausanne, Switzerland
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