1
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Olvera-Rojas M, Plaza-Florido A, Solis-Urra P, Osuna-Prieto FJ, Ortega FB. Neurological-related proteomic profiling in plasma of children with metabolic healthy and unhealthy overweight/obesity. Pediatr Obes 2024:e13155. [PMID: 39075931 DOI: 10.1111/ijpo.13155] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/01/2024] [Revised: 06/13/2024] [Accepted: 07/10/2024] [Indexed: 07/31/2024]
Abstract
OBJECTIVE Children with overweight/obesity (OW/OB) exhibit poor cardiometabolic health, yet mechanisms influencing brain health remain unclear. We examined the differences in neurological-related circulating proteins in plasma among children with metabolically healthy obesity (MHO) and metabolically unhealthy obesity (MUO) and the association with metabolic syndrome markers. METHODS In this cross-sectional study, we included 84 Caucasian children (39% girls), aged 10.1 ± 1.1 years, from the ActiveBrains project (NCT02295072). A ninety-two-protein targeted approach using Olink's® technology was used. RESULTS We identified distinct concentrations of CD38, LAIR2, MANF and NRP2 proteins in MHO compared with MUO. Moreover, individual metabolic syndrome (MS) markers were linked to nine proteins (CD38, CPM, EDA2R, IL12, JAMB, KYNU, LAYN, MSR1 and SMOC2) in children with OW/OB. These proteins play crucial roles in diverse biological processes (e.g., angiogenesis, cholesterol transport, nicotinamide adenine dinucleotide (NAD+) catalysis and maintenance of blood-brain barrier) related to brain health. CONCLUSION Our proteomics study suggests that cardiometabolic health (represented by MHO/MUO or individual MS markers) is associated with the concentration in plasma of several proteins involved in brain health. Larger-scale studies are needed to contrast/confirm these findings, with CD38 standing out as a particularly noteworthy and robust discovery.
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Affiliation(s)
- Marcos Olvera-Rojas
- Department of Physical Education and Sports, Faculty of Sport Sciences, Sport and Health University Research Institute (iMUDS), University of Granada, Granada, Spain
| | - Abel Plaza-Florido
- Department of Physical Education and Sports, Faculty of Sport Sciences, Sport and Health University Research Institute (iMUDS), University of Granada, Granada, Spain
- Pediatric Exercise and Genomics Research Center, Department of Pediatrics, School of Medicine, University of California Irvine, Irvine, California, USA
| | - Patricio Solis-Urra
- Department of Physical Education and Sports, Faculty of Sport Sciences, Sport and Health University Research Institute (iMUDS), University of Granada, Granada, Spain
- Faculty of Education and Social Sciences, Universidad Andres Bello, Viña del Mar, Chile
| | - Francisco J Osuna-Prieto
- Department of Physical Education and Sports, Faculty of Sport Sciences, Sport and Health University Research Institute (iMUDS), University of Granada, Granada, Spain
- Hospital Universitari Joan XXIII de Tarragona, Institut d'Investigació Sanitària Pere Virgili (IISPV), Tarragona, Spain
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Instituto de Salud Carlos III, Madrid, Spain
| | - Francisco B Ortega
- Department of Physical Education and Sports, Faculty of Sport Sciences, Sport and Health University Research Institute (iMUDS), University of Granada, Granada, Spain
- Centro de Investigación Biomédica en Red Fisiopatología de la Obesidad y Nutrición (CIBERobn), Instituto de Salud Carlos III, Madrid, Spain
- Faculty of Sport and Health Sciences, University of Jyväskylä, Jyväskylä, Finland
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2
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Baraibar AM, Colomer T, Moreno-García A, Bernal-Chico A, Sánchez-Martín E, Utrilla C, Serrat R, Soria-Gómez E, Rodríguez-Antigüedad A, Araque A, Matute C, Marsicano G, Mato S. Autoimmune inflammation triggers aberrant astrocytic calcium signaling to impair synaptic plasticity. Brain Behav Immun 2024; 121:192-210. [PMID: 39032542 DOI: 10.1016/j.bbi.2024.07.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/20/2024] [Revised: 07/12/2024] [Accepted: 07/15/2024] [Indexed: 07/23/2024] Open
Abstract
Cortical pathology involving inflammatory and neurodegenerative mechanisms is a hallmark of multiple sclerosis and a correlate of disease progression and cognitive decline. Astrocytes play a pivotal role in multiple sclerosis initiation and progression but astrocyte-neuronal network alterations contributing to gray matter pathology remain undefined. Here we unveil deregulation of astrocytic calcium signaling and astrocyte-to-neuron communication as key pathophysiological mechanisms of cortical dysfunction in the experimental autoimmune encephalomyelitis (EAE) model of multiple sclerosis. Using two-photon imaging ex vivo and fiber photometry in freely behaving mice, we found that acute EAE was associated with the emergence of spontaneously hyperactive cortical astrocytes exhibiting dysfunctional responses to cannabinoid, glutamate and purinoreceptor agonists. Abnormal astrocyte signaling by Gi and Gq protein coupled receptors was observed in the inflamed cortex. This was mirrored by treatments with pro-inflammatory factors both in vitro and ex vivo, suggesting cell-autonomous effects of the cortical neuroinflammatory environment. Finally, deregulated astrocyte calcium activity was associated with an enhancement of glutamatergic gliotransmission and a shift of astrocyte-mediated short-term and long-term plasticity mechanisms towards synaptic potentiation. Overall, our data identify astrocyte-neuronal network dysfunctions as key pathological features of gray matter inflammation in multiple sclerosis and potentially additional neuroimmunological disorders.
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Affiliation(s)
- A M Baraibar
- Department of Neurosciences, University of the Basque Country UPV/EHU, 48940 Leioa, Spain; Achucarro Basque Center for Neuroscience, 48940 Leioa, Spain; Neuroinmunology Group, Biobizkaia Health Research Institute, 48903 Barakaldo, Spain; Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), 28029 Madrid, Spain
| | - T Colomer
- Department of Neurosciences, University of the Basque Country UPV/EHU, 48940 Leioa, Spain; Achucarro Basque Center for Neuroscience, 48940 Leioa, Spain; Neuroinmunology Group, Biobizkaia Health Research Institute, 48903 Barakaldo, Spain
| | - A Moreno-García
- Department of Neurosciences, University of the Basque Country UPV/EHU, 48940 Leioa, Spain; Achucarro Basque Center for Neuroscience, 48940 Leioa, Spain; Neuroinmunology Group, Biobizkaia Health Research Institute, 48903 Barakaldo, Spain
| | - A Bernal-Chico
- Department of Neurosciences, University of the Basque Country UPV/EHU, 48940 Leioa, Spain; Achucarro Basque Center for Neuroscience, 48940 Leioa, Spain; Neuroinmunology Group, Biobizkaia Health Research Institute, 48903 Barakaldo, Spain
| | - E Sánchez-Martín
- Department of Neurosciences, University of the Basque Country UPV/EHU, 48940 Leioa, Spain; Achucarro Basque Center for Neuroscience, 48940 Leioa, Spain; Neuroinmunology Group, Biobizkaia Health Research Institute, 48903 Barakaldo, Spain
| | - C Utrilla
- Department of Neurosciences, University of the Basque Country UPV/EHU, 48940 Leioa, Spain; Achucarro Basque Center for Neuroscience, 48940 Leioa, Spain; Neuroinmunology Group, Biobizkaia Health Research Institute, 48903 Barakaldo, Spain
| | - R Serrat
- Institut National de la Santé et de la Recherche Médicale (INSERM), U1215 NeuroCentre Magendie, 33077 Bordeaux, France; University of Bordeaux, 33077 Bordeaux, France
| | - E Soria-Gómez
- Department of Neurosciences, University of the Basque Country UPV/EHU, 48940 Leioa, Spain; Achucarro Basque Center for Neuroscience, 48940 Leioa, Spain
| | - A Rodríguez-Antigüedad
- Department of Neurosciences, University of the Basque Country UPV/EHU, 48940 Leioa, Spain; Neuroinmunology Group, Biobizkaia Health Research Institute, 48903 Barakaldo, Spain
| | - A Araque
- Department of Neuroscience, University of Minnesota, Minneapolis, 55455 MN, USA
| | - C Matute
- Department of Neurosciences, University of the Basque Country UPV/EHU, 48940 Leioa, Spain; Achucarro Basque Center for Neuroscience, 48940 Leioa, Spain; Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), 28029 Madrid, Spain
| | - G Marsicano
- Institut National de la Santé et de la Recherche Médicale (INSERM), U1215 NeuroCentre Magendie, 33077 Bordeaux, France; University of Bordeaux, 33077 Bordeaux, France.
| | - S Mato
- Department of Neurosciences, University of the Basque Country UPV/EHU, 48940 Leioa, Spain; Achucarro Basque Center for Neuroscience, 48940 Leioa, Spain; Neuroinmunology Group, Biobizkaia Health Research Institute, 48903 Barakaldo, Spain.
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3
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Wu Y, Dai Y, Lefton KB, Holy TE, Papouin T. STARDUST: a pipeline for the unbiased analysis of astrocyte regional calcium dynamics. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.04.588196. [PMID: 38645020 PMCID: PMC11030233 DOI: 10.1101/2024.04.04.588196] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/23/2024]
Abstract
Calcium imaging has become a popular way to probe astrocyte activity, but few analysis methods holistically capture discrete calcium signals that occur across the astrocyte domain. Here, we introduce STARDUST, a pipeline for the Spatio-Temporal Analysis of Regional Dynamics & Unbiased Sorting of Transients from fluorescence recordings of astrocytes, and provide step-by-step guidelines. STARDUST yields fluorescence time-series from data-defined regions of activity and performs systematic signal detection and feature extraction, enabling the in-depth and unbiased study of astrocyte calcium signals.
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Affiliation(s)
- Yifan Wu
- Washington University in St. Louis, Department of Neuroscience, St. Louis, MO 63110 USA
- Technical contact
| | - Yanchao Dai
- Washington University in St. Louis, Department of Neuroscience, St. Louis, MO 63110 USA
| | - Katheryn B. Lefton
- Washington University in St. Louis, Department of Neuroscience, St. Louis, MO 63110 USA
| | - Timothy E. Holy
- Washington University in St. Louis, Department of Neuroscience, St. Louis, MO 63110 USA
| | - Thomas Papouin
- Washington University in St. Louis, Department of Neuroscience, St. Louis, MO 63110 USA
- Lead contact
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4
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Krut' VG, Kalinichenko AL, Maltsev DI, Jappy D, Shevchenko EK, Podgorny OV, Belousov VV. Optogenetic and chemogenetic approaches for modeling neurological disorders in vivo. Prog Neurobiol 2024; 235:102600. [PMID: 38548126 DOI: 10.1016/j.pneurobio.2024.102600] [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: 08/15/2023] [Revised: 02/26/2024] [Accepted: 03/22/2024] [Indexed: 04/01/2024]
Abstract
Animal models of human neurological disorders provide valuable experimental tools which enable us to study various aspects of disorder pathogeneses, ranging from structural abnormalities and disrupted metabolism and signaling to motor and mental deficits, and allow us to test novel therapies in preclinical studies. To be valid, these animal models should recapitulate complex pathological features at the molecular, cellular, tissue, and behavioral levels as closely as possible to those observed in human subjects. Pathological states resembling known human neurological disorders can be induced in animal species by toxins, genetic factors, lesioning, or exposure to extreme conditions. In recent years, novel animal models recapitulating neuropathologies in humans have been introduced. These animal models are based on synthetic biology approaches: opto- and chemogenetics. In this paper, we review recent opto- and chemogenetics-based animal models of human neurological disorders. These models allow for the creation of pathological states by disrupting specific processes at the cellular level. The artificial pathological states mimic a range of human neurological disorders, such as aging-related dementia, Alzheimer's and Parkinson's diseases, amyotrophic lateral sclerosis, epilepsy, and ataxias. Opto- and chemogenetics provide new opportunities unavailable with other animal models of human neurological disorders. These techniques enable researchers to induce neuropathological states varying in severity and ranging from acute to chronic. We also discuss future directions for the development and application of synthetic biology approaches for modeling neurological disorders.
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Affiliation(s)
- Viktoriya G Krut'
- Pirogov Russian National Research Medical University, Moscow 117997, Russia; Federal Center of Brain Research and Neurotechnologies, Federal Medical Biological Agency, Moscow 117997, Russia
| | - Andrei L Kalinichenko
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow 117997, Russia
| | - Dmitry I Maltsev
- Pirogov Russian National Research Medical University, Moscow 117997, Russia; Federal Center of Brain Research and Neurotechnologies, Federal Medical Biological Agency, Moscow 117997, Russia; Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow 117997, Russia
| | - David Jappy
- Federal Center of Brain Research and Neurotechnologies, Federal Medical Biological Agency, Moscow 117997, Russia
| | - Evgeny K Shevchenko
- Federal Center of Brain Research and Neurotechnologies, Federal Medical Biological Agency, Moscow 117997, Russia
| | - Oleg V Podgorny
- Pirogov Russian National Research Medical University, Moscow 117997, Russia; Federal Center of Brain Research and Neurotechnologies, Federal Medical Biological Agency, Moscow 117997, Russia; Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow 117997, Russia.
| | - Vsevolod V Belousov
- Pirogov Russian National Research Medical University, Moscow 117997, Russia; Federal Center of Brain Research and Neurotechnologies, Federal Medical Biological Agency, Moscow 117997, Russia; Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow 117997, Russia; Life Improvement by Future Technologies (LIFT) Center, Skolkovo, Moscow 143025, Russia.
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5
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Edison P. Astroglial activation: Current concepts and future directions. Alzheimers Dement 2024; 20:3034-3053. [PMID: 38305570 PMCID: PMC11032537 DOI: 10.1002/alz.13678] [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: 08/24/2023] [Revised: 11/27/2023] [Accepted: 12/11/2023] [Indexed: 02/03/2024]
Abstract
Astrocytes are abundantly and ubiquitously expressed cell types with diverse functions throughout the central nervous system. Astrocytes show remarkable plasticity and exhibit morphological, molecular, and functional remodeling in response to injury, disease, or infection of the central nervous system, as evident in neurodegenerative diseases. Astroglial mediated inflammation plays a prominent role in the pathogenesis of neurodegenerative diseases. This review focus on the role of astrocytes as essential players in neuroinflammation and discuss their morphological and functional heterogeneity in the normal central nervous system and explore the spatial and temporal variations in astroglial phenotypes observed under different disease conditions. This review discusses the intimate relationship of astrocytes to pathological hallmarks of neurodegenerative diseases. Finally, this review considers the putative therapeutic strategies that can be deployed to modulate the astroglial functions in neurodegenerative diseases. HIGHLIGHTS: Astroglia mediated neuroinflammation plays a key role in the pathogenesis of neurodegenerative diseases. Activated astrocytes exhibit diverse phenotypes in a region-specific manner in brain and interact with β-amyloid, tau, and α-synuclein species as well as with microglia and neuronal circuits. Activated astrocytes are likely to influence the trajectory of disease progression of neurodegenerative diseases, as determined by the stage of disease, individual susceptibility, and state of astroglial priming. Modulation of astroglial activation may be a therapeutic strategy at various stages in the trajectory of neurodegenerative diseases to modify the disease course.
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Affiliation(s)
- Paul Edison
- Division of NeurologyDepartment of Brain SciencesFaculty of Medicine, Imperial College LondonLondonUK
- Division of Psychological medicine and clinical neurosciencesSchool of Medicine, Cardiff UniversityWalesUK
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6
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Postnov D, Semyachkina-Glushkovskaya O, Litvinenko E, Kurths J, Penzel T. Mechanisms of Activation of Brain's Drainage during Sleep: The Nightlife of Astrocytes. Cells 2023; 12:2667. [PMID: 37998402 PMCID: PMC10670149 DOI: 10.3390/cells12222667] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2023] [Revised: 11/09/2023] [Accepted: 11/15/2023] [Indexed: 11/25/2023] Open
Abstract
The study of functions, mechanisms of generation, and pathways of movement of cerebral fluids has a long history, but the last decade has been especially productive. The proposed glymphatic hypothesis, which suggests a mechanism of the brain waste removal system (BWRS), caused an active discussion on both the criticism of some of the perspectives and our intensive study of new experimental facts. It was especially found that the intensity of the metabolite clearance changes significantly during the transition between sleep and wakefulness. Interestingly, at the cellular level, a number of aspects of this problem have been focused on, such as astrocytes-glial cells, which, over the past two decades, have been recognized as equal partners of neurons and perform many important functions. In particular, an important role was assigned to astrocytes within the framework of the glymphatic hypothesis. In this review, we return to the "astrocytocentric" view of the BWRS function and the explanation of its activation during sleep from the viewpoint of new findings over the last decade. Our main conclusion is that the BWRS's action may be analyzed both at the systemic (whole-brain) and at the local (cellular) level. The local level means here that the neuro-glial-vascular unit can also be regarded as the smallest functional unit of sleep, and therefore, the smallest functional unit of the BWRS.
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Affiliation(s)
- Dmitry Postnov
- Department of Optics and Biophotonics, Saratov State University, Astrakhanskaya Str. 83, 410012 Saratov, Russia;
| | - Oxana Semyachkina-Glushkovskaya
- Department of Biology, Saratov State University, Astrakhanskaya Str. 83, 410012 Saratov, Russia; (O.S.-G.); (J.K.)
- Physics Department, Humboldt University, Newtonstrasse 15, 12489 Berlin, Germany
| | - Elena Litvinenko
- Department of Optics and Biophotonics, Saratov State University, Astrakhanskaya Str. 83, 410012 Saratov, Russia;
| | - Jürgen Kurths
- Department of Biology, Saratov State University, Astrakhanskaya Str. 83, 410012 Saratov, Russia; (O.S.-G.); (J.K.)
- Physics Department, Humboldt University, Newtonstrasse 15, 12489 Berlin, Germany
- Potsdam Institute for Climate Impact Research, Telegrafenberg A31, 14473 Potsdam, Germany
| | - Thomas Penzel
- Department of Biology, Saratov State University, Astrakhanskaya Str. 83, 410012 Saratov, Russia; (O.S.-G.); (J.K.)
- Charité — Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany
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7
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Brazhe A, Verisokin A, Verveyko D, Postnov D. Astrocytes: new evidence, new models, new roles. Biophys Rev 2023; 15:1303-1333. [PMID: 37975000 PMCID: PMC10643736 DOI: 10.1007/s12551-023-01145-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Accepted: 09/08/2023] [Indexed: 11/19/2023] Open
Abstract
Astrocytes have been in the limelight of active research for about 3 decades now. Over this period, ideas about their function and role in the nervous system have evolved from simple assistance in energy supply and homeostasis maintenance to a complex informational and metabolic hub that integrates data on local neuronal activity, sensory and arousal context, and orchestrates many crucial processes in the brain. Rapid progress in experimental techniques and data analysis produces a growing body of data, which can be used as a foundation for formulation of new hypotheses, building new refined mathematical models, and ultimately should lead to a new level of understanding of the contribution of astrocytes to the cognitive tasks performed by the brain. Here, we highlight recent progress in astrocyte research, which we believe expands our understanding of how low-level signaling at a cellular level builds up to processes at the level of the whole brain and animal behavior. We start our review with revisiting data on the role of noradrenaline-mediated astrocytic signaling in locomotion, arousal, sensory integration, memory, and sleep. We then briefly review astrocyte contribution to the regulation of cerebral blood flow regulation, which is followed by a discussion of biophysical mechanisms underlying astrocyte effects on different brain processes. The experimental section is closed by an overview of recent experimental techniques available for modulation and visualization of astrocyte dynamics. We then evaluate how the new data can be potentially incorporated into the new mathematical models or where and how it already has been done. Finally, we discuss an interesting prospect that astrocytes may be key players in important processes such as the switching between sleep and wakefulness and the removal of toxic metabolites from the brain milieu.
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Affiliation(s)
- Alexey Brazhe
- Department of Biophysics, Biological Faculty, Lomonosov Moscow State University, Leninskie Gory, 1/24, Moscow, 119234 Russia
- Department of Molecular Neurobiology, Institute of Bioorganic Chemistry RAS, GSP-7, Miklukho-Maklay Str., 16/10, Moscow, 117997 Russia
| | - Andrey Verisokin
- Department of Theoretical Physics, Kursk State University, Radishcheva st., 33, Kursk, 305000 Russia
| | - Darya Verveyko
- Department of Theoretical Physics, Kursk State University, Radishcheva st., 33, Kursk, 305000 Russia
| | - Dmitry Postnov
- Department of Optics and Biophotonics, Saratov State University, Astrakhanskaya st., 83, Saratov, 410012 Russia
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8
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Lim D, Tapella L, Dematteis G, Talmon M, Genazzani AA. Calcineurin Signalling in Astrocytes: From Pathology to Physiology and Control of Neuronal Functions. Neurochem Res 2023; 48:1077-1090. [PMID: 36083398 PMCID: PMC10030417 DOI: 10.1007/s11064-022-03744-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2022] [Revised: 07/31/2022] [Accepted: 08/29/2022] [Indexed: 10/14/2022]
Abstract
Calcineurin (CaN), a Ca2+/calmodulin-activated serine/threonine phosphatase, acts as a Ca2+-sensitive switch regulating cellular functions through protein dephosphorylation and activation of gene transcription. In astrocytes, the principal homeostatic cells in the CNS, over-activation of CaN is known to drive pathological transcriptional remodelling, associated with neuroinflammation in diseases such as Alzheimer's disease, epilepsy and brain trauma. Recent reports suggest that, in physiological conditions, the activity of CaN in astrocytes is transcription-independent and is required for maintenance of basal protein synthesis rate and activation of astrocytic Na+/K+ pump thereby contributing to neuronal functions such as neuronal excitability and memory formation. In this contribution we overview the role of Ca2+ and CaN signalling in astroglial pathophysiology focusing on the emerging physiological role of CaN in astrocytes. We propose a model for the context-dependent switch of CaN activity from the post-transcriptional regulation of cell proteostasis in healthy astrocytes to the CaN-dependent transcriptional activation in neuroinflammation-associated diseases.
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Affiliation(s)
- Dmitry Lim
- Department of Pharmaceutical Sciences, Università del Piemonte Orientale "Amedeo Avogadro", Via Bovio 6, 28100, Novara, Italy.
| | - Laura Tapella
- Department of Pharmaceutical Sciences, Università del Piemonte Orientale "Amedeo Avogadro", Via Bovio 6, 28100, Novara, Italy
| | - Giulia Dematteis
- Department of Pharmaceutical Sciences, Università del Piemonte Orientale "Amedeo Avogadro", Via Bovio 6, 28100, Novara, Italy
| | - Maria Talmon
- Department of Health Sciences, School of Medicine, Università del Piemonte Orientale "Amedeo Avogadro", Via Solaroli 17, 28100, Novara, Italy
| | - Armando A Genazzani
- Department of Pharmaceutical Sciences, Università del Piemonte Orientale "Amedeo Avogadro", Via Bovio 6, 28100, Novara, Italy.
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9
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Salmon CK, Syed TA, Kacerovsky JB, Alivodej N, Schober AL, Sloan TFW, Pratte MT, Rosen MP, Green M, Chirgwin-Dasgupta A, Mehta S, Jilani A, Wang Y, Vali H, Mandato CA, Siddiqi K, Murai KK. Organizing principles of astrocytic nanoarchitecture in the mouse cerebral cortex. Curr Biol 2023; 33:957-972.e5. [PMID: 36805126 DOI: 10.1016/j.cub.2023.01.043] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Revised: 12/01/2022] [Accepted: 01/20/2023] [Indexed: 02/18/2023]
Abstract
Astrocytes are increasingly understood to be important regulators of central nervous system (CNS) function in health and disease; yet, we have little quantitative understanding of their complex architecture. While broad categories of astrocytic structures are known, the discrete building blocks that compose them, along with their geometry and organizing principles, are poorly understood. Quantitative investigation of astrocytic complexity is impeded by the absence of high-resolution datasets and robust computational approaches to analyze these intricate cells. To address this, we produced four ultra-high-resolution datasets of mouse cerebral cortex using serial electron microscopy and developed astrocyte-tailored computer vision methods for accurate structural analysis. We unearthed specific anatomical building blocks, structural motifs, connectivity hubs, and hierarchical organizations of astrocytes. Furthermore, we found that astrocytes interact with discrete clusters of synapses and that astrocytic mitochondria are distributed to lie closer to larger clusters of synapses. Our findings provide a geometrically principled, quantitative understanding of astrocytic nanoarchitecture and point to an unexpected level of complexity in how astrocytes interact with CNS microanatomy.
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Affiliation(s)
- Christopher K Salmon
- Centre for Research in Neuroscience, Department of Neurology & Neurosurgery, Brain Repair and Integrative Neuroscience Program, The Research Institute of the McGill University Health Centre, Montreal General Hospital, 1650 Cedar Avenue, Montreal, QC H3G 1A4, Canada
| | - Tabish A Syed
- School of Computer Science and Centre for Intelligent Machines, McGill University, 3480 Rue University, Montreal, QC H3A 2A7, Canada; MILA - Québec AI Institute, 6666 Rue Saint-Urbain, Montreal, QC H2S 3H1, Canada
| | - J Benjamin Kacerovsky
- Centre for Research in Neuroscience, Department of Neurology & Neurosurgery, Brain Repair and Integrative Neuroscience Program, The Research Institute of the McGill University Health Centre, Montreal General Hospital, 1650 Cedar Avenue, Montreal, QC H3G 1A4, Canada
| | - Nensi Alivodej
- Centre for Research in Neuroscience, Department of Neurology & Neurosurgery, Brain Repair and Integrative Neuroscience Program, The Research Institute of the McGill University Health Centre, Montreal General Hospital, 1650 Cedar Avenue, Montreal, QC H3G 1A4, Canada
| | - Alexandra L Schober
- Centre for Research in Neuroscience, Department of Neurology & Neurosurgery, Brain Repair and Integrative Neuroscience Program, The Research Institute of the McGill University Health Centre, Montreal General Hospital, 1650 Cedar Avenue, Montreal, QC H3G 1A4, Canada
| | | | - Michael T Pratte
- Centre for Research in Neuroscience, Department of Neurology & Neurosurgery, Brain Repair and Integrative Neuroscience Program, The Research Institute of the McGill University Health Centre, Montreal General Hospital, 1650 Cedar Avenue, Montreal, QC H3G 1A4, Canada
| | - Michael P Rosen
- Centre for Research in Neuroscience, Department of Neurology & Neurosurgery, Brain Repair and Integrative Neuroscience Program, The Research Institute of the McGill University Health Centre, Montreal General Hospital, 1650 Cedar Avenue, Montreal, QC H3G 1A4, Canada
| | - Miranda Green
- Centre for Research in Neuroscience, Department of Neurology & Neurosurgery, Brain Repair and Integrative Neuroscience Program, The Research Institute of the McGill University Health Centre, Montreal General Hospital, 1650 Cedar Avenue, Montreal, QC H3G 1A4, Canada
| | - Adario Chirgwin-Dasgupta
- Centre for Research in Neuroscience, Department of Neurology & Neurosurgery, Brain Repair and Integrative Neuroscience Program, The Research Institute of the McGill University Health Centre, Montreal General Hospital, 1650 Cedar Avenue, Montreal, QC H3G 1A4, Canada
| | - Shaurya Mehta
- School of Computer Science and Centre for Intelligent Machines, McGill University, 3480 Rue University, Montreal, QC H3A 2A7, Canada
| | - Affan Jilani
- School of Computer Science and Centre for Intelligent Machines, McGill University, 3480 Rue University, Montreal, QC H3A 2A7, Canada
| | - Yanan Wang
- School of Computer Science and Centre for Intelligent Machines, McGill University, 3480 Rue University, Montreal, QC H3A 2A7, Canada
| | - Hojatollah Vali
- Department of Anatomy & Cell Biology, McGill University, 3640 Rue University, Montreal, QC H3A 0C7, Canada
| | - Craig A Mandato
- Department of Anatomy & Cell Biology, McGill University, 3640 Rue University, Montreal, QC H3A 0C7, Canada
| | - Kaleem Siddiqi
- School of Computer Science and Centre for Intelligent Machines, McGill University, 3480 Rue University, Montreal, QC H3A 2A7, Canada; MILA - Québec AI Institute, 6666 Rue Saint-Urbain, Montreal, QC H2S 3H1, Canada.
| | - Keith K Murai
- Centre for Research in Neuroscience, Department of Neurology & Neurosurgery, Brain Repair and Integrative Neuroscience Program, The Research Institute of the McGill University Health Centre, Montreal General Hospital, 1650 Cedar Avenue, Montreal, QC H3G 1A4, Canada.
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10
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Thapaliya P, Pape N, Rose CR, Ullah G. Modeling the heterogeneity of sodium and calcium homeostasis between cortical and hippocampal astrocytes and its impact on bioenergetics. Front Cell Neurosci 2023; 17:1035553. [PMID: 36794264 PMCID: PMC9922870 DOI: 10.3389/fncel.2023.1035553] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Accepted: 01/13/2023] [Indexed: 01/31/2023] Open
Abstract
Emerging evidence indicates that neuronal activity-evoked changes in sodium concentration in astrocytes Na a represent a special form of excitability, which is tightly linked to all other major ions in the astrocyte and extracellular space, as well as to bioenergetics, neurotransmitter uptake, and neurovascular coupling. Recently, one of us reported that Na a transients in the neocortex have a significantly higher amplitude than those in the hippocampus. Based on the extensive data from that study, here we develop a detailed biophysical model to further understand the origin of this heterogeneity and how it affects bioenergetics in the astrocytes. In addition to closely fitting the observed experimental Na a changes under different conditions, our model shows that the heterogeneity in Na a signaling leads to substantial differences in the dynamics of astrocytic Ca2+ signals in the two brain regions, and leaves cortical astrocytes more susceptible to Na+ and Ca2+ overload under metabolic stress. The model also predicts that activity-evoked Na a transients result in significantly larger ATP consumption in cortical astrocytes than in the hippocampus. The difference in ATP consumption is mainly due to the different expression levels of NMDA receptors in the two regions. We confirm predictions from our model experimentally by fluorescence-based measurement of glutamate-induced changes in ATP levels in neocortical and hippocampal astrocytes in the absence and presence of the NMDA receptor's antagonist (2R)-amino-5-phosphonovaleric acid.
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Affiliation(s)
- Pawan Thapaliya
- Department of Physics, University of South Florida, Tampa, FL, United States
| | - Nils Pape
- Faculty of Mathematics and Natural Sciences, Institute of Neurobiology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Christine R. Rose
- Faculty of Mathematics and Natural Sciences, Institute of Neurobiology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Ghanim Ullah
- Department of Physics, University of South Florida, Tampa, FL, United States,*Correspondence: Ghanim Ullah ✉
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11
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Noriega‐Prieto JA, Kofuji P, Araque A. Endocannabinoid signaling in synaptic function. Glia 2023; 71:36-43. [PMID: 36408881 PMCID: PMC9679333 DOI: 10.1002/glia.24256] [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: 03/16/2022] [Revised: 07/02/2022] [Accepted: 07/25/2022] [Indexed: 01/09/2023]
Abstract
In the last decades, astrocytes have emerged as important regulatory cells actively involved in brain function by exchanging signaling with neurons. The endocannabinoid (eCB) signaling is widely present in many brain areas, being crucially involved in multiple brain functions and animal behaviors. The present review presents and discusses current evidence demonstrating that astrocytes sense eCBs released during neuronal activity and subsequently release gliotransmitters that regulate synaptic transmission and plasticity. The eCB signaling to astrocytes and the synaptic regulation mediated by astrocytes activated by eCBs are complex phenomena that exhibit exquisite spatial and temporal properties, a wide variety of downstream signaling mechanisms, and a large diversity of functional synaptic outcomes. Studies investigating this topic have revealed novel regulatory processes of synaptic function, like the lateral regulation of synaptic transmission and the active involvement of astrocytes in the spike-timing dependent plasticity, originally thought to be exclusively mediated by the coincident activity of pre- and postsynaptic neurons, following Hebbian rules for associative learning. Finally, the critical influence of astrocyte-mediated eCB signaling on animal behavior is also discussed.
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Affiliation(s)
| | - Paulo Kofuji
- Department of NeuroscienceUniversity of MinnesotaMinneapolisMinnesotaUSA
| | - Alfonso Araque
- Department of NeuroscienceUniversity of MinnesotaMinneapolisMinnesotaUSA
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12
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Denizot A, Arizono M, Nägerl UV, Berry H, De Schutter E. Control of Ca 2+ signals by astrocyte nanoscale morphology at tripartite synapses. Glia 2022; 70:2378-2391. [PMID: 36097958 PMCID: PMC9825906 DOI: 10.1002/glia.24258] [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: 04/26/2022] [Revised: 07/20/2022] [Accepted: 07/28/2022] [Indexed: 01/11/2023]
Abstract
Much of the Ca2+ activity in astrocytes is spatially restricted to microdomains and occurs in fine processes that form a complex anatomical meshwork, the so-called spongiform domain. A growing body of literature indicates that those astrocytic Ca2+ signals can influence the activity of neuronal synapses and thus tune the flow of information through neuronal circuits. Because of technical difficulties in accessing the small spatial scale involved, the role of astrocyte morphology on Ca2+ microdomain activity remains poorly understood. Here, we use computational tools and idealized 3D geometries of fine processes based on recent super-resolution microscopy data to investigate the mechanistic link between astrocytic nanoscale morphology and local Ca2+ activity. Simulations demonstrate that the nano-morphology of astrocytic processes powerfully shapes the spatio-temporal properties of Ca2+ signals and promotes local Ca2+ activity. The model predicts that this effect is attenuated upon astrocytic swelling, hallmark of brain diseases, which we confirm experimentally in hypo-osmotic conditions. Upon repeated neurotransmitter release events, the model predicts that swelling hinders astrocytic signal propagation. Overall, this study highlights the influence of the complex morphology of astrocytes at the nanoscale and its remodeling in pathological conditions on neuron-astrocyte communication at so-called tripartite synapses, where astrocytic processes come into close contact with pre- and postsynaptic structures.
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Affiliation(s)
- Audrey Denizot
- Computational Neuroscience UnitOkinawa Institute of Science and TechnologyOnna‐SonJapan
| | - Misa Arizono
- Interdisciplinary Institute for NeuroscienceUniversité de BordeauxBordeauxFrance,Interdisciplinary Institute for NeuroscienceCNRS UMR 5297BordeauxFrance,Department of PharmacologyKyoto University Graduate School of MedicineKyotoJapan
| | - U. Valentin Nägerl
- Interdisciplinary Institute for NeuroscienceUniversité de BordeauxBordeauxFrance,Interdisciplinary Institute for NeuroscienceCNRS UMR 5297BordeauxFrance
| | - Hugues Berry
- LIRIS, UMR5205 CNRSUniv LyonVilleurbanneFrance,INRIAVilleurbanneFrance
| | - Erik De Schutter
- Computational Neuroscience UnitOkinawa Institute of Science and TechnologyOnna‐SonJapan
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13
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Avoiding interpretational pitfalls in fluorescence imaging of the brain. Nat Rev Neurosci 2022; 23:705-706. [PMID: 36207503 DOI: 10.1038/s41583-022-00643-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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14
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Blum Moyse L, Berry H. Modelling the modulation of cortical Up-Down state switching by astrocytes. PLoS Comput Biol 2022; 18:e1010296. [PMID: 35862433 PMCID: PMC9345492 DOI: 10.1371/journal.pcbi.1010296] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Revised: 08/02/2022] [Accepted: 06/11/2022] [Indexed: 11/18/2022] Open
Abstract
Up-Down synchronization in neuronal networks refers to spontaneous switches between periods of high collective firing activity (Up state) and periods of silence (Down state). Recent experimental reports have shown that astrocytes can control the emergence of such Up-Down regimes in neural networks, although the molecular or cellular mechanisms that are involved are still uncertain. Here we propose neural network models made of three populations of cells: excitatory neurons, inhibitory neurons and astrocytes, interconnected by synaptic and gliotransmission events, to explore how astrocytes can control this phenomenon. The presence of astrocytes in the models is indeed observed to promote the emergence of Up-Down regimes with realistic characteristics. Our models show that the difference of signalling timescales between astrocytes and neurons (seconds versus milliseconds) can induce a regime where the frequency of gliotransmission events released by the astrocytes does not synchronize with the Up and Down phases of the neurons, but remains essentially stable. However, these gliotransmission events are found to change the localization of the bifurcations in the parameter space so that with the addition of astrocytes, the network enters a bistability region of the dynamics that corresponds to Up-Down synchronization. Taken together, our work provides a theoretical framework to test scenarios and hypotheses on the modulation of Up-Down dynamics by gliotransmission from astrocytes. Neural networks in many brain regions can display synchronized activities. During the so-called “Up-Down” synchronization regimes for instance, the whole local population of neurons switches in a spontaneous and synchronized fashion between phases of high activity (Up states) and phases of low activity (Down states). The mechanisms responsible for this behaviour are still not well understood, but recent experimental reports have suggested that another type of brain cells, the astrocytes, at least partly control these oscillations. Astrocytes are increasingly believed to play a role in the propagation of signals between neurons, via their connections to neuronal synapses, but how this mechanism could control Up-Down regimes is not understood. To address this issue we present here simple mathematical models of neuronal networks that incorporate astrocytes in addition to neurons according to various levels of description. Using bifurcation analysis and numerical simulations we explore how astrocytes control Up-Down synchronization of the neuronal networks. In particular, astrocytes in the model are found to change the localization of the bifurcation points in the parameter space, so that the neurons enter the region of Up-Down regime when astrocytes are present. We also give some theoretical predictions that can be tested experimentally to test the validity of our models.
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Affiliation(s)
- Lisa Blum Moyse
- Inria, Villeurbanne, France
- LIRIS UMR5205, University of Lyon, Villeurbanne, France
| | - Hugues Berry
- Inria, Villeurbanne, France
- LIRIS UMR5205, University of Lyon, Villeurbanne, France
- * E-mail:
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15
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A closer look at astrocyte morphology: Development, heterogeneity, and plasticity at astrocyte leaflets. Curr Opin Neurobiol 2022; 74:102550. [PMID: 35544965 PMCID: PMC9376008 DOI: 10.1016/j.conb.2022.102550] [Citation(s) in RCA: 31] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Revised: 03/20/2022] [Accepted: 04/03/2022] [Indexed: 11/20/2022]
Abstract
Astrocytes represent an abundant type of glial cell involved in nearly every aspect of central nervous system (CNS) function, including synapse formation and maturation, ion and neurotransmitter homeostasis, blood-brain barrier maintenance, as well as neuronal metabolic support. These various functions are enabled by the morphological complexity that astrocytes adopt. Recent experimental advances in genetic and viral labeling, lineage tracing, and live- and ultrastructural imaging of miniscule astrocytic sub-compartments reveal a complex morphological heterogeneity that is based on the origin, local function, and environmental context in which astrocytes reside. In this minireview, we highlight recent findings that reveal the plastic nature of astrocytes in the healthy brain, particularly at the synapse, and emerging technologies that have advanced our understanding of these morphologically complex cells.
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16
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Nakajima H, Fujita S, Kakae M, Nagayasu K, Oh-Hora M, Shirakawa H, Kaneko S. Orai2 channel regulates prostaglandin E 2 production in TNFα/IL1α-stimulated astrocytes. Glia 2022; 70:1666-1680. [PMID: 35506586 DOI: 10.1002/glia.24188] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2021] [Revised: 04/19/2022] [Accepted: 04/25/2022] [Indexed: 01/04/2023]
Abstract
Astrocytes are glial cells that serve homeostatic functions in the central nervous system (CNS). Recent research, however, suggests that under pathological conditions, astrocytes are stimulated by various factors and actively participate in CNS inflammation. In the present study, we found that astrocytes upregulate various inflammatory factors including prostaglandin E2 (PGE2 ) by co-stimulation with tumor necrosis factor-alpha (TNFα) and interleukin-1alpha (IL1α). These TNFα/IL1α-stimulated astrocytes also showed increased Ca2+ release from the endoplasmic reticulum (ER) and increased expression of Orai2, a member of the store-operated calcium channel (SOCC) family. To reveal the role of Orai2, we used astrocytes in which Orai2 was knocked-down (KD) or knocked-out (KO). The expression of the prostaglandin E synthase Ptges and the production of PGE2 were higher in Orai2-KD astrocytes than in WT astrocytes when stimulated with TNFα and IL1α. Orai2-KO astrocytes also showed increased expression of Ptges and increased PGE2 production. The expression of Ptgs2, another PGE2 synthetic enzyme, was also upregulated in Orai2-KO astrocytes. Moreover, Orai2-KO astrocytes showed increased store-operated calcium entry (SOCE) and increased Orai1 expression. These results suggest that Orai2 is upregulated in TNFα/IL1α-stimulated astrocytes and reduces PGE2 production to some extent, modulating CNS inflammation. Our findings may aid in understanding how astrocytes are associated with inflammatory responses, and the identification of new targets that modulate astrocytic reactivity.
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Affiliation(s)
- Hiroki Nakajima
- Department of Molecular Pharmacology, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan
| | - Sayaka Fujita
- Department of Molecular Pharmacology, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan
| | - Masashi Kakae
- Department of Molecular Pharmacology, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan
| | - Kazuki Nagayasu
- Department of Molecular Pharmacology, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan
| | - Masatsugu Oh-Hora
- Department of Biochemistry, Juntendo University School of Medicine, Tokyo, Japan.,Division of Molecular Immunology, Research Center for Infectious Diseases, Medical Institute of Bioregulation, Kyusyu University, Fukuoka, Japan.,Laboratory of Molecular Immunology, Immunology Frontier Research Center, Osaka University, Suita, Japan
| | - Hisashi Shirakawa
- Department of Molecular Pharmacology, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan
| | - Shuji Kaneko
- Department of Molecular Pharmacology, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan
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17
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Oliveira JF, Araque A. Astrocyte regulation of neural circuit activity and network states. Glia 2022; 70:1455-1466. [PMID: 35460131 PMCID: PMC9232995 DOI: 10.1002/glia.24178] [Citation(s) in RCA: 26] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Revised: 02/23/2022] [Accepted: 02/27/2022] [Indexed: 12/13/2022]
Abstract
Astrocytes are known to influence neuronal activity through different mechanisms, including the homeostatic control of extracellular levels of ions and neurotransmitters and the exchange of signaling molecules that regulate synaptic formation, structure, and function. While a great effort done in the past has defined many molecular mechanisms and cellular processes involved in astrocyte-neuron interactions at the cellular level, the consequences of these interactions at the network level in vivo have only relatively recently been identified. This review describes and discusses recent findings on the regulatory effects of astrocytes on the activity of neuronal networks in vivo. Accumulating but still limited, evidence indicates that astrocytes regulate neuronal network rhythmic activity and synchronization as well as brain states. These studies demonstrate a critical contribution of astrocytes to brain activity and are paving the way for a more thorough understanding of the cellular bases of brain function.
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Affiliation(s)
- João Filipe Oliveira
- Life and Health Sciences Research Institute (ICVS), School of Health Sciences, University of Minho, Braga, Portugal.,ICVS/3B's-PT Government Associate Laboratory, Braga, Portugal.,IPCA-EST-2Ai, Polytechnic Institute of Cávado and Ave, Applied Artificial Intelligence Laboratory, Campus of IPCA, Barcelos, Portugal
| | - Alfonso Araque
- Department of Neuroscience, University of Minnesota, Minneapolis, Minnesota, USA
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18
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Gorzo KA, Gordon GR. Photonics tools begin to clarify astrocyte calcium transients. NEUROPHOTONICS 2022; 9:021907. [PMID: 35211642 PMCID: PMC8857908 DOI: 10.1117/1.nph.9.2.021907] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Accepted: 02/01/2022] [Indexed: 05/27/2023]
Abstract
Astrocytes integrate information from neurons and the microvasculature to coordinate brain activity and metabolism. Using a variety of calcium-dependent cellular mechanisms, these cells impact numerous aspects of neurophysiology in health and disease. Astrocyte calcium signaling is highly diverse, with complex spatiotemporal features. Here, we review astrocyte calcium dynamics and the optical imaging tools used to measure and analyze these events. We briefly cover historical calcium measurements, followed by our current understanding of how calcium transients relate to the structure of astrocytes. We then explore newer photonics tools including super-resolution techniques and genetically encoded calcium indicators targeted to specific cellular compartments and how these have been applied to astrocyte biology. Finally, we provide a brief overview of analysis software used to accurately quantify the data and ultimately aid in our interpretation of the various functions of astrocyte calcium transients.
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Affiliation(s)
- Kelsea A. Gorzo
- University of Calgary, Hotchkiss Brain Institute, Cumming School of Medicine, Calgary, Alberta, Canada
| | - Grant R. Gordon
- University of Calgary, Hotchkiss Brain Institute, Cumming School of Medicine, Calgary, Alberta, Canada
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19
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Ultrastructural view of astrocyte arborization, astrocyte-astrocyte and astrocyte-synapse contacts, intracellular vesicle-like structures, and mitochondrial network. Prog Neurobiol 2022; 213:102264. [DOI: 10.1016/j.pneurobio.2022.102264] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Revised: 02/25/2022] [Accepted: 03/08/2022] [Indexed: 12/15/2022]
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20
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Estimating the glutamate transporter surface density in distinct sub-cellular compartments of mouse hippocampal astrocytes. PLoS Comput Biol 2022; 18:e1009845. [PMID: 35120128 PMCID: PMC8849624 DOI: 10.1371/journal.pcbi.1009845] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Revised: 02/16/2022] [Accepted: 01/18/2022] [Indexed: 11/19/2022] Open
Abstract
Glutamate transporters preserve the spatial specificity of synaptic transmission by limiting glutamate diffusion away from the synaptic cleft, and prevent excitotoxicity by keeping the extracellular concentration of glutamate at low nanomolar levels. Glutamate transporters are abundantly expressed in astrocytes, and previous estimates have been obtained about their surface expression in astrocytes of the rat hippocampus and cerebellum. Analogous estimates for the mouse hippocampus are currently not available. In this work, we derive the surface density of astrocytic glutamate transporters in mice of different ages via quantitative dot blot. We find that the surface density of glial glutamate transporters is similar in 7-8 week old mice and rats. In mice, the levels of glutamate transporters increase until about 6 months of age and then begin to decline slowly. Our data, obtained from a combination of experimental and modeling approaches, point to the existence of stark differences in the density of expression of glutamate transporters across different sub-cellular compartments, indicating that the extent to which astrocytes limit extrasynaptic glutamate diffusion depends not only on their level of synaptic coverage, but also on the identity of the astrocyte compartment in contact with the synapse. Together, these findings provide information on how heterogeneity in the spatial distribution of glutamate transporters in the plasma membrane of hippocampal astrocytes my alter glutamate receptor activation out of the synaptic cleft.
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21
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Sun Q, Hu Y, Deng S, Xiong Y, Huang Z. A visualization pipeline for <i>in vivo</i> two-photon volumetric astrocytic calcium imaging. J Biomed Res 2022; 36:358-367. [PMID: 36130733 PMCID: PMC9548438 DOI: 10.7555/jbr.36.20220099] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Astrocytes, the multi-functional glial cells with the most abundant population in the brain, integrate information across their territories to regulate neuronal synaptic and cerebrovascular activities. Astrocytic calcium (Ca2+) signaling is the major readout of cellular functional state of astrocytes. The conventional two-photon in vivo imaging usually focuses on a single horizontal focal plane to capture the astrocytic Ca2+ signals, which leaves >80% spatial information undetected. To fully probe the Ca2+ activity across the whole astrocytic territory, we developed a pipeline for imaging and visualizing volumetric astrocytic Ca2+ time-lapse images. With the pipeline, we discovered a new signal distribution pattern from three-dimensional (3D) astrocytic Ca2+ imaging data of mice under isoflurane anesthetic states. The tools developed in this study enable a better understanding of the spatiotemporal patterns of astrocytic activity in 3D space.
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Affiliation(s)
- Qian Sun
- Department of Pharmacology, School of Basic Medical Science, Fudan University, Shanghai 200032, China
| | - Yusi Hu
- Department of Pharmacology, School of Basic Medical Science, Fudan University, Shanghai 200032, China
- State Key Laboratory of Medical Neurobiology, Institutes of Brain Science and Collaborative Innovation Center for Brain Science, Fudan University, Shanghai 200032, China
| | - Saiyue Deng
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430030, China
| | - Yanyu Xiong
- Department of Pharmacology, School of Basic Medical Science, Fudan University, Shanghai 200032, China
- State Key Laboratory of Medical Neurobiology, Institutes of Brain Science and Collaborative Innovation Center for Brain Science, Fudan University, Shanghai 200032, China
| | - Zhili Huang
- Department of Pharmacology, School of Basic Medical Science, Fudan University, Shanghai 200032, China
- State Key Laboratory of Medical Neurobiology, Institutes of Brain Science and Collaborative Innovation Center for Brain Science, Fudan University, Shanghai 200032, China
- Zhili Huang, Department of Pharmacology, School of Basic Medical Science, Fudan University, 130 Dong'an Road, Shanghai 200032, China. Tel/Fax: +86-21-54237043/+86-21-54237103, E-mail:
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22
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Astrocyte Gliotransmission in the Regulation of Systemic Metabolism. Metabolites 2021; 11:metabo11110732. [PMID: 34822390 PMCID: PMC8623475 DOI: 10.3390/metabo11110732] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Revised: 10/25/2021] [Accepted: 10/26/2021] [Indexed: 12/28/2022] Open
Abstract
Normal brain function highly relies on the appropriate functioning of astrocytes. These glial cells are strategically situated between blood vessels and neurons, provide significant substrate support to neuronal demand, and are sensitive to neuronal activity and energy-related molecules. Astrocytes respond to many metabolic conditions and regulate a wide array of physiological processes, including cerebral vascular remodeling, glucose sensing, feeding, and circadian rhythms for the control of systemic metabolism and behavior-related responses. This regulation ultimately elicits counterregulatory mechanisms in order to couple whole-body energy availability with brain function. Therefore, understanding the role of astrocyte crosstalk with neighboring cells via the release of molecules, e.g., gliotransmitters, into the parenchyma in response to metabolic and neuronal cues is of fundamental relevance to elucidate the distinct roles of these glial cells in the neuroendocrine control of metabolism. Here, we review the mechanisms underlying astrocyte-released gliotransmitters that have been reported to be crucial for maintaining homeostatic regulation of systemic metabolism.
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23
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Sun J, Song Y, Chen Z, Qiu J, Zhu S, Wu L, Xing L. Heterogeneity and Molecular Markers for CNS Glial Cells Revealed by Single-Cell Transcriptomics. Cell Mol Neurobiol 2021; 42:2629-2642. [PMID: 34704168 DOI: 10.1007/s10571-021-01159-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Accepted: 10/17/2021] [Indexed: 12/11/2022]
Abstract
Glial cells, including astrocytes, oligodendrocytes, and microglia, are the major components in the central nervous system (CNS). Studies have revealed the heterogeneity of each glial cell type and that they each may play distinct roles in physiological processes and/or neurological diseases. Single-cell sequencing (scRNA-seq) technology developed in recent years has extended our understanding of glial cell heterogeneity from the perspective of transcriptome profiling. This review summarizes the marker genes of major glial cells in the CNS and reveals their heterogeneity in different species, CNS regions, developmental stages, and pathological states (Alzheimer's disease and spinal cord injury), expanding our knowledge of glial cell heterogeneity on both molecular and functional levels.
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Affiliation(s)
- Junjie Sun
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, NMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology Products, Jiangsu Clinical Medicine Center of Tissue Engineering and Nerve Injury Repair, Co-Innovation Center of Neuroregeneration, Nantong University, 19 Qixiu Road, Nantong, 226001, Jiangsu, China
| | - Yixing Song
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, NMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology Products, Jiangsu Clinical Medicine Center of Tissue Engineering and Nerve Injury Repair, Co-Innovation Center of Neuroregeneration, Nantong University, 19 Qixiu Road, Nantong, 226001, Jiangsu, China
| | - Zhiheng Chen
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, NMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology Products, Jiangsu Clinical Medicine Center of Tissue Engineering and Nerve Injury Repair, Co-Innovation Center of Neuroregeneration, Nantong University, 19 Qixiu Road, Nantong, 226001, Jiangsu, China
| | - Jiaying Qiu
- Department of Prenatal Screening and Diagnosis Center, Nantong Maternal and Child Health Hospital affiliated to Nantong University, Nantong, 226001, Jiangsu, China
| | - Shunxing Zhu
- Laboratory Animal Center, Nantong University, Nantong, 226001, China
| | - Liucheng Wu
- Laboratory Animal Center, Nantong University, Nantong, 226001, China.
| | - Lingyan Xing
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, NMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology Products, Jiangsu Clinical Medicine Center of Tissue Engineering and Nerve Injury Repair, Co-Innovation Center of Neuroregeneration, Nantong University, 19 Qixiu Road, Nantong, 226001, Jiangsu, China.
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24
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Arizono M, Nägerl UV. Deciphering the functional nano-anatomy of the tripartite synapse using stimulated emission depletion microscopy. Glia 2021; 70:607-618. [PMID: 34664734 DOI: 10.1002/glia.24103] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Revised: 09/24/2021] [Accepted: 09/30/2021] [Indexed: 11/12/2022]
Abstract
A major challenge for studying neuron-astrocyte communication lies in visualizing the tripartite synapse, which is the physical site where astrocytic processes contact and interact with neuronal synapses. While conventional light microscopy cannot resolve the anatomical details of the tripartite synapse, electron microscopy only provides ultrastructural snapshots that tell us little about its living state and dynamics. Stimulated emission depletion (STED) microscopy is a super-resolution fluorescence imaging technique that can provide live images of tripartite synapses with nanoscale spatial resolution. It is compatible with physiology experiments and imaging in the intact brain in vivo, opening up new opportunities to link the nanoscale structure of the tripartite system with functional readouts of neurons and astrocytes or even behavior. In this review, we first summarize the findings and insights from previous studies addressing the structure-function relationship of the tripartite synapse using conventional imaging techniques. We then explain the basic principle of STED microscopy and the main challenges facing its application to live-tissue imaging of fine astrocytic processes. We summarize insights from our recent STED studies, which revealed new aspects of the structure and physiology of the tripartite synapse and the surrounding extracellular space. Finally, we discuss how the STED approach and other advanced optical techniques can illuminate the role of astrocytes for brain physiology and animal behavior.
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Affiliation(s)
- Misa Arizono
- Interdisciplinary Institute for Neuroscience, Université de Bordeaux, Bordeaux, France.,Interdisciplinary Institute for Neuroscience, CNRS UMR, Bordeaux, France
| | - U Valentin Nägerl
- Interdisciplinary Institute for Neuroscience, Université de Bordeaux, Bordeaux, France.,Interdisciplinary Institute for Neuroscience, CNRS UMR, Bordeaux, France
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25
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Mielnicka A, Michaluk P. Exocytosis in Astrocytes. Biomolecules 2021; 11:1367. [PMID: 34572580 PMCID: PMC8471187 DOI: 10.3390/biom11091367] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Revised: 09/10/2021] [Accepted: 09/14/2021] [Indexed: 12/17/2022] Open
Abstract
Until recently, astrocytes were thought to be a part of a simple "brain glue" providing only a supporting role for neurons. However, the discoveries of the last two decades have proven astrocytes to be dynamic partners participating in brain metabolism and actively influencing communication between neurons. The means of astrocyte-neuron communication are diverse, although regulated exocytosis has received the most attention but also caused the most debate. Similar to most of eukaryotic cells, astrocytes have a complex range of vesicular organelles which can undergo exocytosis as well as intricate molecular mechanisms that regulate this process. In this review, we focus on the components needed for regulated exocytosis to occur and summarise the knowledge about experimental evidence showing its presence in astrocytes.
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Affiliation(s)
| | - Piotr Michaluk
- BRAINCITY, Laboratory of Neurobiology, The Nencki Institute of Experimental Biology, PAS, 02-093 Warsaw, Poland;
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26
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Prieto-Villalobos J, Alvear TF, Liberona A, Lucero CM, Martínez-Araya CJ, Balmazabal J, Inostroza CA, Ramírez G, Gómez GI, Orellana JA. Astroglial Hemichannels and Pannexons: The Hidden Link between Maternal Inflammation and Neurological Disorders. Int J Mol Sci 2021; 22:ijms22179503. [PMID: 34502412 PMCID: PMC8430734 DOI: 10.3390/ijms22179503] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Revised: 08/30/2021] [Accepted: 08/30/2021] [Indexed: 12/11/2022] Open
Abstract
Maternal inflammation during pregnancy causes later-in-life alterations of the offspring’s brain structure and function. These abnormalities increase the risk of developing several psychiatric and neurological disorders, including schizophrenia, intellectual disability, bipolar disorder, autism spectrum disorder, microcephaly, and cerebral palsy. Here, we discuss how astrocytes might contribute to postnatal brain dysfunction following maternal inflammation, focusing on the signaling mediated by two families of plasma membrane channels: hemi-channels and pannexons. [Ca2+]i imbalance linked to the opening of astrocytic hemichannels and pannexons could disturb essential functions that sustain astrocytic survival and astrocyte-to-neuron support, including energy and redox homeostasis, uptake of K+ and glutamate, and the delivery of neurotrophic factors and energy-rich metabolites. Both phenomena could make neurons more susceptible to the harmful effect of prenatal inflammation and the experience of a second immune challenge during adulthood. On the other hand, maternal inflammation could cause excitotoxicity by producing the release of high amounts of gliotransmitters via astrocytic hemichannels/pannexons, eliciting further neuronal damage. Understanding how hemichannels and pannexons participate in maternal inflammation-induced brain abnormalities could be critical for developing pharmacological therapies against neurological disorders observed in the offspring.
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Affiliation(s)
- Juan Prieto-Villalobos
- Departamento de Neurología, Escuela de Medicina and Centro Interdisciplinario de Neurociencias, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago 8330024, Chile; (J.P.-V.); (T.F.A.); (A.L.); (C.J.M.-A.); (J.B.); (C.A.I.); (G.R.)
| | - Tanhia F. Alvear
- Departamento de Neurología, Escuela de Medicina and Centro Interdisciplinario de Neurociencias, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago 8330024, Chile; (J.P.-V.); (T.F.A.); (A.L.); (C.J.M.-A.); (J.B.); (C.A.I.); (G.R.)
| | - Andrés Liberona
- Departamento de Neurología, Escuela de Medicina and Centro Interdisciplinario de Neurociencias, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago 8330024, Chile; (J.P.-V.); (T.F.A.); (A.L.); (C.J.M.-A.); (J.B.); (C.A.I.); (G.R.)
| | - Claudia M. Lucero
- Institute of Biomedical Sciences, Faculty of Health Sciences, Universidad Autónoma de Chile, Santiago 8910060, Chile; (C.M.L.); (G.I.G.)
| | - Claudio J. Martínez-Araya
- Departamento de Neurología, Escuela de Medicina and Centro Interdisciplinario de Neurociencias, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago 8330024, Chile; (J.P.-V.); (T.F.A.); (A.L.); (C.J.M.-A.); (J.B.); (C.A.I.); (G.R.)
| | - Javiera Balmazabal
- Departamento de Neurología, Escuela de Medicina and Centro Interdisciplinario de Neurociencias, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago 8330024, Chile; (J.P.-V.); (T.F.A.); (A.L.); (C.J.M.-A.); (J.B.); (C.A.I.); (G.R.)
| | - Carla A. Inostroza
- Departamento de Neurología, Escuela de Medicina and Centro Interdisciplinario de Neurociencias, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago 8330024, Chile; (J.P.-V.); (T.F.A.); (A.L.); (C.J.M.-A.); (J.B.); (C.A.I.); (G.R.)
| | - Gigliola Ramírez
- Departamento de Neurología, Escuela de Medicina and Centro Interdisciplinario de Neurociencias, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago 8330024, Chile; (J.P.-V.); (T.F.A.); (A.L.); (C.J.M.-A.); (J.B.); (C.A.I.); (G.R.)
| | - Gonzalo I. Gómez
- Institute of Biomedical Sciences, Faculty of Health Sciences, Universidad Autónoma de Chile, Santiago 8910060, Chile; (C.M.L.); (G.I.G.)
| | - Juan A. Orellana
- Departamento de Neurología, Escuela de Medicina and Centro Interdisciplinario de Neurociencias, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago 8330024, Chile; (J.P.-V.); (T.F.A.); (A.L.); (C.J.M.-A.); (J.B.); (C.A.I.); (G.R.)
- Correspondence: ; Tel.: +56-23548105
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27
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Schweigmann M, Caudal LC, Stopper G, Scheller A, Koch KP, Kirchhoff F. Versatile Surface Electrodes for Combined Electrophysiology and Two-Photon Imaging of the Mouse Central Nervous System. Front Cell Neurosci 2021; 15:720675. [PMID: 34447299 PMCID: PMC8383317 DOI: 10.3389/fncel.2021.720675] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Accepted: 07/19/2021] [Indexed: 11/23/2022] Open
Abstract
Understanding and modulating CNS function in physiological as well as pathophysiological contexts remains a significant ambition in research and clinical applications. The investigation of the multifaceted CNS cell types including their interactions and contributions to neural function requires a combination of the state-of-the-art in vivo electrophysiology and imaging techniques. We developed a novel type of liquid crystal polymer (LCP) surface micro-electrode manufactured in three customized designs with up to 16 channels for recording and stimulation of brain activity. All designs include spare central spaces for simultaneous 2P-imaging. Nanoporous platinum-plated contact sites ensure a low impedance and high current transfer. The epidural implantation of the LCP micro-electrodes could be combined with standard cranial window surgery. The epidurally positioned electrodes did not only display long-term biocompatibility, but we also observed an additional stabilization of the underlying CNS tissue. We demonstrate the electrode’s versatility in combination with in vivo 2P-imaging by monitoring anesthesia-awake cycles of transgenic mice with GCaMP3 expression in neurons or astrocytes. Cortical stimulation and simultaneous 2P Ca2+ imaging in neurons or astrocytes highlighted the astrocytes’ integrative character in neuronal activity processing. Furthermore, we confirmed that spontaneous astroglial Ca2+ signals are dampened under anesthesia, while evoked signals in neurons and astrocytes showed stronger dependency on stimulation intensity rather than on various levels of anesthesia. Finally, we show that the electrodes provide recordings of the electrocorticogram (ECoG) with a high signal-to noise ratio and spatial signal differences which help to decipher brain activity states during experimental procedures. Summarizing, the novel LCP surface micro-electrode is a versatile, convenient, and reliable tool to investigate brain function in vivo.
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Affiliation(s)
- Michael Schweigmann
- Molecular Physiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), University of Saarland, Homburg, Germany.,Department of Electrical Engineering, Trier University of Applied Sciences, Trier, Germany
| | - Laura C Caudal
- Molecular Physiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), University of Saarland, Homburg, Germany
| | - Gebhard Stopper
- Molecular Physiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), University of Saarland, Homburg, Germany
| | - Anja Scheller
- Molecular Physiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), University of Saarland, Homburg, Germany
| | - Klaus P Koch
- Department of Electrical Engineering, Trier University of Applied Sciences, Trier, Germany
| | - Frank Kirchhoff
- Molecular Physiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), University of Saarland, Homburg, Germany
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28
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Sherwood MW, Arizono M, Panatier A, Mikoshiba K, Oliet SHR. Astrocytic IP 3Rs: Beyond IP 3R2. Front Cell Neurosci 2021; 15:695817. [PMID: 34393726 PMCID: PMC8363081 DOI: 10.3389/fncel.2021.695817] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Accepted: 06/30/2021] [Indexed: 12/31/2022] Open
Abstract
Astrocytes are sensitive to ongoing neuronal/network activities and, accordingly, regulate neuronal functions (synaptic transmission, synaptic plasticity, behavior, etc.) by the context-dependent release of several gliotransmitters (e.g., glutamate, glycine, D-serine, ATP). To sense diverse input, astrocytes express a plethora of G-protein coupled receptors, which couple, via Gi/o and Gq, to the intracellular Ca2+ release channel IP3-receptor (IP3R). Indeed, manipulating astrocytic IP3R-Ca2+ signaling is highly consequential at the network and behavioral level: Depleting IP3R subtype 2 (IP3R2) results in reduced GPCR-Ca2+ signaling and impaired synaptic plasticity; enhancing IP3R-Ca2+ signaling affects cognitive functions such as learning and memory, sleep, and mood. However, as a result of discrepancies in the literature, the role of GPCR-IP3R-Ca2+ signaling, especially under physiological conditions, remains inconclusive. One primary reason for this could be that IP3R2 has been used to represent all astrocytic IP3Rs, including IP3R1 and IP3R3. Indeed, IP3R1 and IP3R3 are unique Ca2+ channels in their own right; they have unique biophysical properties, often display distinct distribution, and are differentially regulated. As a result, they mediate different physiological roles to IP3R2. Thus, these additional channels promise to enrich the diversity of spatiotemporal Ca2+ dynamics and provide unique opportunities for integrating neuronal input and modulating astrocyte–neuron communication. The current review weighs evidence supporting the existence of multiple astrocytic-IP3R isoforms, summarizes distinct sub-type specific properties that shape spatiotemporal Ca2+ dynamics. We also discuss existing experimental tools and future refinements to better recapitulate the endogenous activities of each IP3R isoform.
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Affiliation(s)
- Mark W Sherwood
- University of Bordeaux, INSERM, Neurocentre Magendie, U1215, Bordeaux, France
| | - Misa Arizono
- University of Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297, Bordeaux, France
| | - Aude Panatier
- University of Bordeaux, INSERM, Neurocentre Magendie, U1215, Bordeaux, France
| | - Katsuhiko Mikoshiba
- ShanghaiTech University, Shanghai, China.,Faculty of Science, Toho University, Funabashi, Japan.,RIKEN CLST, Kobe, Japan
| | - Stéphane H R Oliet
- University of Bordeaux, INSERM, Neurocentre Magendie, U1215, Bordeaux, France
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29
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Durkee C, Kofuji P, Navarrete M, Araque A. Astrocyte and neuron cooperation in long-term depression. Trends Neurosci 2021; 44:837-848. [PMID: 34334233 DOI: 10.1016/j.tins.2021.07.004] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Revised: 07/06/2021] [Accepted: 07/07/2021] [Indexed: 01/28/2023]
Abstract
Activity-dependent long-term changes in synaptic transmission known as synaptic plasticity are fundamental processes in brain function and are recognized as the cellular basis of learning and memory. While the neuronal mechanisms underlying synaptic plasticity have been largely identified, the involvement of astrocytes in these processes has been less recognized. However, astrocytes are emerging as important cells that regulate synaptic function by interacting with neurons at tripartite synapses. In this review, we discuss recent evidence suggesting that astrocytes are necessary elements in long-term synaptic depression (LTD). We highlight the mechanistic heterogeneity of astrocyte contribution to this form of synaptic plasticity and propose that astrocytes are integral participants in LTD.
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Affiliation(s)
- Caitlin Durkee
- Department of Neuroscience, University of Minnesota, Minneapolis, MN 55455, USA
| | - Paulo Kofuji
- Department of Neuroscience, University of Minnesota, Minneapolis, MN 55455, USA
| | | | - Alfonso Araque
- Department of Neuroscience, University of Minnesota, Minneapolis, MN 55455, USA.
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30
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Van Horn MR, Benfey NJ, Shikany C, Severs LJ, Deemyad T. Neuron-astrocyte networking: astrocytes orchestrate and respond to changes in neuronal network activity across brain states and behaviors. J Neurophysiol 2021; 126:627-636. [PMID: 34259027 DOI: 10.1152/jn.00062.2021] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Astrocytes are known to play many important roles in brain function. However, research underscoring the extent to which astrocytes modulate neuronal activity is still underway. Here we review the latest evidence regarding the contribution of astrocytes to neuronal oscillations across the brain, with a specific focus on how astrocytes respond to changes in brain state (e.g., sleep, arousal, stress). We then discuss the general mechanisms by which astrocytes signal to neurons to modulate neuronal activity, ultimately driving changes in behavior, followed by a discussion of how astrocytes contribute to respiratory rhythms in the medulla. Finally, we contemplate the possibility that brain stem astrocytes could modulate brainwide oscillations by communicating the status of oxygenation to higher cortical areas.
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Affiliation(s)
- Marion R Van Horn
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada
| | - Nicholas J Benfey
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada
| | - Colleen Shikany
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, Washington
| | - Liza J Severs
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, Washington.,Department of Physiology and Biophysics, The University of Washington, Seattle, Washington
| | - Tara Deemyad
- Department of Psychiatry, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania
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31
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Lia A, Henriques VJ, Zonta M, Chiavegato A, Carmignoto G, Gómez-Gonzalo M, Losi G. Calcium Signals in Astrocyte Microdomains, a Decade of Great Advances. Front Cell Neurosci 2021; 15:673433. [PMID: 34163329 PMCID: PMC8216559 DOI: 10.3389/fncel.2021.673433] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2021] [Accepted: 04/23/2021] [Indexed: 12/13/2022] Open
Abstract
The glial cells astrocytes have long been recognized as important neuron-supporting elements in brain development, homeostasis, and metabolism. After the discovery that the reciprocal communication between astrocytes and neurons is a fundamental mechanism in the modulation of neuronal synaptic communication, over the last two decades astrocytes became a hot topic in neuroscience research. Crucial to their functional interactions with neurons are the cytosolic Ca2+ elevations that mediate gliotransmission. Large attention has been posed to the so-called Ca2+microdomains, dynamic Ca2+ changes spatially restricted to fine astrocytic processes including perisynaptic astrocytic processes (PAPs). With presynaptic terminals and postsynaptic neuronal membranes, PAPs compose the tripartite synapse. The distinct spatial-temporal features and functional roles of astrocyte microdomain Ca2+ activity remain poorly defined. However, thanks to the development of genetically encoded Ca2+ indicators (GECIs), advanced microscopy techniques, and innovative analytical approaches, Ca2+ transients in astrocyte microdomains were recently studied in unprecedented detail. These events have been observed to occur much more frequently (∼50–100-fold) and dynamically than somatic Ca2+ elevations with mechanisms that likely involve both IP3-dependent and -independent pathways. Further progress aimed to clarify the complex, dynamic machinery responsible for astrocytic Ca2+ activity at microdomains is a crucial step in our understanding of the astrocyte role in brain function and may also reveal astrocytes as novel therapeutic targets for different brain diseases. Here, we review the most recent studies that improve our mechanistic understanding of the essential features of astrocyte Ca2+ microdomains.
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Affiliation(s)
- Annamaria Lia
- Neuroscience Institute, National Research Council (IN-CNR), Padua, Italy.,Department of Biomedical Sciences, University of Padua, Padua, Italy
| | - Vanessa Jorge Henriques
- Neuroscience Institute, National Research Council (IN-CNR), Padua, Italy.,Department of Biomedical Sciences, University of Padua, Padua, Italy
| | - Micaela Zonta
- Neuroscience Institute, National Research Council (IN-CNR), Padua, Italy.,Department of Biomedical Sciences, University of Padua, Padua, Italy
| | - Angela Chiavegato
- Department of Biomedical Sciences, University of Padua, Padua, Italy
| | - Giorgio Carmignoto
- Neuroscience Institute, National Research Council (IN-CNR), Padua, Italy.,Department of Biomedical Sciences, University of Padua, Padua, Italy
| | - Marta Gómez-Gonzalo
- Neuroscience Institute, National Research Council (IN-CNR), Padua, Italy.,Department of Biomedical Sciences, University of Padua, Padua, Italy
| | - Gabriele Losi
- Neuroscience Institute, National Research Council (IN-CNR), Padua, Italy.,Department of Biomedical Sciences, University of Padua, Padua, Italy
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32
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Chiareli RA, Carvalho GA, Marques BL, Mota LS, Oliveira-Lima OC, Gomes RM, Birbrair A, Gomez RS, Simão F, Klempin F, Leist M, Pinto MCX. The Role of Astrocytes in the Neurorepair Process. Front Cell Dev Biol 2021; 9:665795. [PMID: 34113618 PMCID: PMC8186445 DOI: 10.3389/fcell.2021.665795] [Citation(s) in RCA: 43] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Accepted: 04/29/2021] [Indexed: 12/17/2022] Open
Abstract
Astrocytes are highly specialized glial cells responsible for trophic and metabolic support of neurons. They are associated to ionic homeostasis, the regulation of cerebral blood flow and metabolism, the modulation of synaptic activity by capturing and recycle of neurotransmitters and maintenance of the blood-brain barrier. During injuries and infections, astrocytes act in cerebral defense through heterogeneous and progressive changes in their gene expression, morphology, proliferative capacity, and function, which is known as reactive astrocytes. Thus, reactive astrocytes release several signaling molecules that modulates and contributes to the defense against injuries and infection in the central nervous system. Therefore, deciphering the complex signaling pathways of reactive astrocytes after brain damage can contribute to the neuroinflammation control and reveal new molecular targets to stimulate neurorepair process. In this review, we present the current knowledge about the role of astrocytes in brain damage and repair, highlighting the cellular and molecular bases involved in synaptogenesis and neurogenesis. In addition, we present new approaches to modulate the astrocytic activity and potentiates the neurorepair process after brain damage.
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Affiliation(s)
| | | | | | - Lennia Soares Mota
- Department of Pharmacology, Federal University of Goias, Goiânia, Brazil
| | | | | | - Alexander Birbrair
- Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, Brazil
| | - Renato Santiago Gomez
- Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, Brazil
| | - Fabrício Simão
- Research Division, Vascular Cell Biology, Joslin Diabetes Center and Harvard Medical School, Boston, MA, United States
| | | | - Marcel Leist
- Konstanz Research School Chemical Biology, University of Konstanz, Konstanz, Germany
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33
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Hardy E, Cohen-Salmon M, Rouach N, Rancillac A. Astroglial Cx30 differentially impacts synaptic activity from hippocampal principal cells and interneurons. Glia 2021; 69:2178-2198. [PMID: 33973274 DOI: 10.1002/glia.24017] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Revised: 04/24/2021] [Accepted: 04/28/2021] [Indexed: 01/09/2023]
Abstract
Astrocytes play important roles in brain function via dynamic structural and functional interactions with neurons. Yet the underlying mechanisms remain poorly defined. A typical feature of astrocytes is the high expression of connexins, which mediate their extensive intercellular communication and regulate their structural properties. In particular, connexin 30 (Cx30), one of the two connexins abundantly expressed by astrocytes, was recently shown to be a critical regulator of excitatory synaptic transmission by controlling the astroglial coverage of synapses. However, the role of Cx30 in the regulation of inhibitory synaptic transmission and excitatory/inhibitory balance remains elusive. Here, we investigated the role of astroglial Cx30 on the electrophysiological and morphological properties of five classes of hippocampal CA1 stratum oriens and pyramidale neurons, defined by the unsupervised Ward's clustering. Using Cx30 knockout mice, we found that Cx30 alters specific properties of some subsets of CA1 interneurons, such as resting membrane potential and sag ratio, while other parameters, such as action potential threshold and saturation frequency, were more frequently altered among the different classes of neurons. The excitation-inhibition balance was also differentially and selectively modulated among the different neuron subtypes. Only slight morphological differences were observed on reconstructed neurons. Altogether, these data indicate that Cx30 differentially alters the electrophysiological and morphological properties of hippocampal cell populations, and modulates both their excitatory and inhibitory inputs. Astrocytes, via Cx30, are thus active modulators of both excitatory and inhibitory synapses in the hippocampus.
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Affiliation(s)
- Eléonore Hardy
- Neuroglial Interactions in Cerebral Physiopathology, Center for Interdisciplinary Research in Biology (CIRB), Collège de France, Centre National de la Recherche Scientifique (CNRS) Unité Mixte de Recherche UMR 7241, Institut National de la Santé et de la Recherche Médicale (INSERM) U1050, Labex Memolife, PSL-Research University, Paris, France
| | - Martine Cohen-Salmon
- Physiology and Physiopathology of the Gliovascular Unit Research Group, Center for Interdisciplinary Research in Biology (CIRB), Collège de France, Centre National de la Recherche Scientifique (CNRS) Unité Mixte de Recherche UMR 7241, Institut National de la Santé et de la Recherche Médicale (INSERM) U1050, Labex Memolife, PSL-Research University, Paris, France
| | - Nathalie Rouach
- Neuroglial Interactions in Cerebral Physiopathology, Center for Interdisciplinary Research in Biology (CIRB), Collège de France, Centre National de la Recherche Scientifique (CNRS) Unité Mixte de Recherche UMR 7241, Institut National de la Santé et de la Recherche Médicale (INSERM) U1050, Labex Memolife, PSL-Research University, Paris, France
| | - Armelle Rancillac
- Neuroglial Interactions in Cerebral Physiopathology, Center for Interdisciplinary Research in Biology (CIRB), Collège de France, Centre National de la Recherche Scientifique (CNRS) Unité Mixte de Recherche UMR 7241, Institut National de la Santé et de la Recherche Médicale (INSERM) U1050, Labex Memolife, PSL-Research University, Paris, France
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34
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Héja L, Szabó Z, Péter M, Kardos J. Spontaneous Ca 2+ Fluctuations Arise in Thin Astrocytic Processes With Real 3D Geometry. Front Cell Neurosci 2021; 15:617989. [PMID: 33732110 PMCID: PMC7957061 DOI: 10.3389/fncel.2021.617989] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Accepted: 01/18/2021] [Indexed: 12/16/2022] Open
Abstract
Fluctuations of cytosolic Ca2+ concentration in astrocytes are regarded as a critical non-neuronal signal to regulate neuronal functions. Although such fluctuations can be evoked by neuronal activity, rhythmic astrocytic Ca2+ oscillations may also spontaneously arise. Experimental studies hint that these spontaneous astrocytic Ca2+ oscillations may lie behind different kinds of emerging neuronal synchronized activities, like epileptogenic bursts or slow-wave rhythms. Despite the potential importance of spontaneous Ca2+ oscillations in astrocytes, the mechanism by which they develop is poorly understood. Using simple 3D synapse models and kinetic data of astrocytic Glu transporters (EAATs) and the Na+/Ca2+ exchanger (NCX), we have previously shown that NCX activity alone can generate markedly stable, spontaneous Ca2+ oscillation in the astrocytic leaflet microdomain. Here, we extend that model by incorporating experimentally determined real 3D geometries of 208 excitatory synapses reconstructed from publicly available ultra-resolution electron microscopy datasets. Our simulations predict that the surface/volume ratio (SVR) of peri-synaptic astrocytic processes prominently dictates whether NCX-mediated spontaneous Ca2+ oscillations emerge. We also show that increased levels of intracellular astrocytic Na+ concentration facilitate the appearance of Ca2+ fluctuations. These results further support the principal role of the dynamical reshaping of astrocyte processes in the generation of intrinsic Ca2+ oscillations and their spreading over larger astrocytic compartments.
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Affiliation(s)
- László Héja
- Functional Pharmacology Research Group, Institute of Organic Chemistry, Research Centre for Natural Sciences, Hungarian Academy of Sciences (MTA), Budapest, Hungary
| | - Zsolt Szabó
- Functional Pharmacology Research Group, Institute of Organic Chemistry, Research Centre for Natural Sciences, Hungarian Academy of Sciences (MTA), Budapest, Hungary
| | - Márton Péter
- Functional Pharmacology Research Group, Institute of Organic Chemistry, Research Centre for Natural Sciences, Hungarian Academy of Sciences (MTA), Budapest, Hungary.,Hevesy György PhD School of Chemistry, ELTE Eötvös Loránd University, Budapest, Hungary
| | - Julianna Kardos
- Functional Pharmacology Research Group, Institute of Organic Chemistry, Research Centre for Natural Sciences, Hungarian Academy of Sciences (MTA), Budapest, Hungary
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35
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Wahis J, Holt MG. Astrocytes, Noradrenaline, α1-Adrenoreceptors, and Neuromodulation: Evidence and Unanswered Questions. Front Cell Neurosci 2021; 15:645691. [PMID: 33716677 PMCID: PMC7947346 DOI: 10.3389/fncel.2021.645691] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Accepted: 02/03/2021] [Indexed: 12/27/2022] Open
Abstract
Noradrenaline is a major neuromodulator in the central nervous system (CNS). It is released from varicosities on neuronal efferents, which originate principally from the main noradrenergic nuclei of the brain - the locus coeruleus - and spread throughout the parenchyma. Noradrenaline is released in response to various stimuli and has complex physiological effects, in large part due to the wide diversity of noradrenergic receptors expressed in the brain, which trigger diverse signaling pathways. In general, however, its main effect on CNS function appears to be to increase arousal state. Although the effects of noradrenaline have been researched extensively, the majority of studies have assumed that noradrenaline exerts its effects by acting directly on neurons. However, neurons are not the only cells in the CNS expressing noradrenaline receptors. Astrocytes are responsive to a range of neuromodulators - including noradrenaline. In fact, noradrenaline evokes robust calcium transients in astrocytes across brain regions, through activation of α1-adrenoreceptors. Crucially, astrocytes ensheath neurons at synapses and are known to modulate synaptic activity. Hence, astrocytes are in a key position to relay, or amplify, the effects of noradrenaline on neurons, most notably by modulating inhibitory transmission. Based on a critical appraisal of the current literature, we use this review to argue that a better understanding of astrocyte-mediated noradrenaline signaling is therefore essential, if we are ever to fully understand CNS function. We discuss the emerging concept of astrocyte heterogeneity and speculate on how this might impact the noradrenergic modulation of neuronal circuits. Finally, we outline possible experimental strategies to clearly delineate the role(s) of astrocytes in noradrenergic signaling, and neuromodulation in general, highlighting the urgent need for more specific and flexible experimental tools.
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Affiliation(s)
- Jérôme Wahis
- Laboratory of Glia Biology, VIB-KU Leuven Center for Brain and Disease Research, Leuven, Belgium
- Department of Neurosciences, KU Leuven, Leuven, Belgium
- Leuven Brain Institute, Leuven, Belgium
| | - Matthew G. Holt
- Laboratory of Glia Biology, VIB-KU Leuven Center for Brain and Disease Research, Leuven, Belgium
- Department of Neurosciences, KU Leuven, Leuven, Belgium
- Leuven Brain Institute, Leuven, Belgium
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Toricelli M, Pereira AAR, Souza Abrao G, Malerba HN, Maia J, Buck HS, Viel TA. Mechanisms of neuroplasticity and brain degeneration: strategies for protection during the aging process. Neural Regen Res 2021; 16:58-67. [PMID: 32788448 PMCID: PMC7818866 DOI: 10.4103/1673-5374.286952] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Aging is a dynamic and progressive process that begins at conception and continues until death. This process leads to a decrease in homeostasis and morphological, biochemical and psychological changes, increasing the individual’s vulnerability to various diseases. The growth in the number of aging populations has increased the prevalence of chronic degenerative diseases, impairment of the central nervous system and dementias, such as Alzheimer’s disease, whose main risk factor is age, leading to an increase of the number of individuals who need daily support for life activities. Some theories about aging suggest it is caused by an increase of cellular senescence and reactive oxygen species, which leads to inflammation, oxidation, cell membrane damage and consequently neuronal death. Also, mitochondrial mutations, which are generated throughout the aging process, can lead to changes in energy production, deficiencies in electron transport and apoptosis induction that can result in decreased function. Additionally, increasing cellular senescence and the release of proinflammatory cytokines can cause irreversible damage to neuronal cells. Recent reports point to the importance of changing lifestyle by increasing physical exercise, improving nutrition and environmental enrichment to activate neuroprotective defense mechanisms. Therefore, this review aims to address the latest information about the different mechanisms related to neuroplasticity and neuronal death and to provide strategies that can improve neuroprotection and decrease the neurodegeneration caused by aging and environmental stressors.
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Affiliation(s)
- Mariana Toricelli
- Department of Physiological Sciences, Santa Casa de Sao Paulo School of Medical Sciences, Sao Paulo, Brazil
| | - Arthur Antonio Ruiz Pereira
- Laboratory of Neurobiology of Aging, School of Arts, Sciences and Humanities, Universidade de São Paulo, Sao Paulo, Brazil
| | - Guilherme Souza Abrao
- Laboratory of Neurobiology of Aging, School of Arts, Sciences and Humanities, Universidade de São Paulo, Sao Paulo, Brazil
| | - Helena Nascimento Malerba
- Laboratory of Neurobiology of Aging, School of Arts, Sciences and Humanities, Universidade de São Paulo, Sao Paulo, Brazil
| | - Julia Maia
- Laboratory of Neurobiology of Aging, School of Arts, Sciences and Humanities, Universidade de São Paulo, Sao Paulo, Brazil
| | - Hudson Sousa Buck
- Department of Physiological Sciences, Santa Casa de Sao Paulo School of Medical Sciences, Sao Paulo, Brazil
| | - Tania Araujo Viel
- Laboratory of Neurobiology of Aging, School of Arts, Sciences and Humanities, Universidade de São Paulo, Sao Paulo, Brazil
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Piccialli I, Tedeschi V, Boscia F, Ciccone R, Casamassa A, de Rosa V, Grieco P, Secondo A, Pannaccione A. The Anemonia sulcata Toxin BDS-I Protects Astrocytes Exposed to Aβ 1-42 Oligomers by Restoring [Ca 2+] i Transients and ER Ca 2+ Signaling. Toxins (Basel) 2020; 13:20. [PMID: 33396295 PMCID: PMC7823622 DOI: 10.3390/toxins13010020] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 12/22/2020] [Accepted: 12/24/2020] [Indexed: 12/28/2022] Open
Abstract
Intracellular calcium concentration ([Ca2+]i) transients in astrocytes represent a highly plastic signaling pathway underlying the communication between neurons and glial cells. However, how this important phenomenon may be compromised in Alzheimer's disease (AD) remains unexplored. Moreover, the involvement of several K+ channels, including KV3.4 underlying the fast-inactivating currents, has been demonstrated in several AD models. Here, the effect of KV3.4 modulation by the marine toxin blood depressing substance-I (BDS-I) extracted from Anemonia sulcata has been studied on [Ca2+]i transients in rat primary cortical astrocytes exposed to Aβ1-42 oligomers. We showed that: (1) primary cortical astrocytes expressing KV3.4 channels displayed [Ca2+]i transients depending on the occurrence of membrane potential spikes, (2) BDS-I restored, in a dose-dependent way, [Ca2+]i transients in astrocytes exposed to Aβ1-42 oligomers (5 µM/48 h) by inhibiting hyperfunctional KV3.4 channels, (3) BDS-I counteracted Ca2+ overload into the endoplasmic reticulum (ER) induced by Aβ1-42 oligomers, (4) BDS-I prevented the expression of the ER stress markers including active caspase 12 and GRP78/BiP in astrocytes treated with Aβ1-42 oligomers, and (5) BDS-I prevented Aβ1-42-induced reactive oxygen species (ROS) production and cell suffering measured as mitochondrial activity and lactate dehydrogenase (LDH) release. Collectively, we proposed that the marine toxin BDS-I, by inhibiting the hyperfunctional KV3.4 channels and restoring [Ca2+]i oscillation frequency, prevented Aβ1-42-induced ER stress and cell suffering in astrocytes.
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Affiliation(s)
- Ilaria Piccialli
- Division of Pharmacology, Department of Neuroscience, Reproductive and Dentistry Sciences, School of Medicine, Federico II University of Naples, 80131 Napoli, Italy; (I.P.); (V.T.); (F.B.); (R.C.); (A.C.); (V.d.R.)
| | - Valentina Tedeschi
- Division of Pharmacology, Department of Neuroscience, Reproductive and Dentistry Sciences, School of Medicine, Federico II University of Naples, 80131 Napoli, Italy; (I.P.); (V.T.); (F.B.); (R.C.); (A.C.); (V.d.R.)
| | - Francesca Boscia
- Division of Pharmacology, Department of Neuroscience, Reproductive and Dentistry Sciences, School of Medicine, Federico II University of Naples, 80131 Napoli, Italy; (I.P.); (V.T.); (F.B.); (R.C.); (A.C.); (V.d.R.)
| | - Roselia Ciccone
- Division of Pharmacology, Department of Neuroscience, Reproductive and Dentistry Sciences, School of Medicine, Federico II University of Naples, 80131 Napoli, Italy; (I.P.); (V.T.); (F.B.); (R.C.); (A.C.); (V.d.R.)
| | - Antonella Casamassa
- Division of Pharmacology, Department of Neuroscience, Reproductive and Dentistry Sciences, School of Medicine, Federico II University of Naples, 80131 Napoli, Italy; (I.P.); (V.T.); (F.B.); (R.C.); (A.C.); (V.d.R.)
| | - Valeria de Rosa
- Division of Pharmacology, Department of Neuroscience, Reproductive and Dentistry Sciences, School of Medicine, Federico II University of Naples, 80131 Napoli, Italy; (I.P.); (V.T.); (F.B.); (R.C.); (A.C.); (V.d.R.)
| | - Paolo Grieco
- Department of Pharmacy, School of Medicine, Federico II Universityof Naples, 80131 Napoli, Italy;
| | - Agnese Secondo
- Division of Pharmacology, Department of Neuroscience, Reproductive and Dentistry Sciences, School of Medicine, Federico II University of Naples, 80131 Napoli, Italy; (I.P.); (V.T.); (F.B.); (R.C.); (A.C.); (V.d.R.)
| | - Anna Pannaccione
- Division of Pharmacology, Department of Neuroscience, Reproductive and Dentistry Sciences, School of Medicine, Federico II University of Naples, 80131 Napoli, Italy; (I.P.); (V.T.); (F.B.); (R.C.); (A.C.); (V.d.R.)
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Leventoux N, Morimoto S, Imaizumi K, Sato Y, Takahashi S, Mashima K, Ishikawa M, Sonn I, Kondo T, Watanabe H, Okano H. Human Astrocytes Model Derived from Induced Pluripotent Stem Cells. Cells 2020; 9:E2680. [PMID: 33322219 PMCID: PMC7763297 DOI: 10.3390/cells9122680] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2020] [Revised: 12/04/2020] [Accepted: 12/10/2020] [Indexed: 02/06/2023] Open
Abstract
Induced pluripotent stem cell (iPSC)-based disease modeling has a great potential for uncovering the mechanisms of pathogenesis, especially in the case of neurodegenerative diseases where disease-susceptible cells can usually not be obtained from patients. So far, the iPSC-based modeling of neurodegenerative diseases has mainly focused on neurons because the protocols for generating astrocytes from iPSCs have not been fully established. The growing evidence of astrocytes' contribution to neurodegenerative diseases has underscored the lack of iPSC-derived astrocyte models. In the present study, we established a protocol to efficiently generate iPSC-derived astrocytes (iPasts), which were further characterized by RNA and protein expression profiles as well as functional assays. iPasts exhibited calcium dynamics and glutamate uptake activity comparable to human primary astrocytes. Moreover, when co-cultured with neurons, iPasts enhanced neuronal synaptic maturation. Our protocol can be used for modeling astrocyte-related disease phenotypes in vitro and further exploring the contribution of astrocytes to neurodegenerative diseases.
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Affiliation(s)
- Nicolas Leventoux
- Department of Physiology, Keio University School of Medicine, Tokyo 160-8582, Japan; (N.L.); (S.M.); (K.I.); (S.T.); (K.M.); (M.I.); (I.S.); (T.K.); (H.W.)
| | - Satoru Morimoto
- Department of Physiology, Keio University School of Medicine, Tokyo 160-8582, Japan; (N.L.); (S.M.); (K.I.); (S.T.); (K.M.); (M.I.); (I.S.); (T.K.); (H.W.)
| | - Kent Imaizumi
- Department of Physiology, Keio University School of Medicine, Tokyo 160-8582, Japan; (N.L.); (S.M.); (K.I.); (S.T.); (K.M.); (M.I.); (I.S.); (T.K.); (H.W.)
| | - Yuta Sato
- Keio University Graduate School of Science and Technology, Kanagawa 223-8522, Japan;
- Laboratory for Marmoset Neural Architecture, RIKEN Center for Brain Science, Wako City, Saitama 351-0198, Japan
| | - Shinichi Takahashi
- Department of Physiology, Keio University School of Medicine, Tokyo 160-8582, Japan; (N.L.); (S.M.); (K.I.); (S.T.); (K.M.); (M.I.); (I.S.); (T.K.); (H.W.)
- Department of Neurology and Stroke, Saitama Medical University International Medical Center, 1397-1 Yamane, Hidaka-shi, Saitama 350-1298, Japan
| | - Kyoko Mashima
- Department of Physiology, Keio University School of Medicine, Tokyo 160-8582, Japan; (N.L.); (S.M.); (K.I.); (S.T.); (K.M.); (M.I.); (I.S.); (T.K.); (H.W.)
| | - Mitsuru Ishikawa
- Department of Physiology, Keio University School of Medicine, Tokyo 160-8582, Japan; (N.L.); (S.M.); (K.I.); (S.T.); (K.M.); (M.I.); (I.S.); (T.K.); (H.W.)
| | - Iki Sonn
- Department of Physiology, Keio University School of Medicine, Tokyo 160-8582, Japan; (N.L.); (S.M.); (K.I.); (S.T.); (K.M.); (M.I.); (I.S.); (T.K.); (H.W.)
| | - Takahiro Kondo
- Department of Physiology, Keio University School of Medicine, Tokyo 160-8582, Japan; (N.L.); (S.M.); (K.I.); (S.T.); (K.M.); (M.I.); (I.S.); (T.K.); (H.W.)
| | - Hirotaka Watanabe
- Department of Physiology, Keio University School of Medicine, Tokyo 160-8582, Japan; (N.L.); (S.M.); (K.I.); (S.T.); (K.M.); (M.I.); (I.S.); (T.K.); (H.W.)
| | - Hideyuki Okano
- Department of Physiology, Keio University School of Medicine, Tokyo 160-8582, Japan; (N.L.); (S.M.); (K.I.); (S.T.); (K.M.); (M.I.); (I.S.); (T.K.); (H.W.)
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Henneberger C, Bard L, Panatier A, Reynolds JP, Kopach O, Medvedev NI, Minge D, Herde MK, Anders S, Kraev I, Heller JP, Rama S, Zheng K, Jensen TP, Sanchez-Romero I, Jackson CJ, Janovjak H, Ottersen OP, Nagelhus EA, Oliet SHR, Stewart MG, Nägerl UV, Rusakov DA. LTP Induction Boosts Glutamate Spillover by Driving Withdrawal of Perisynaptic Astroglia. Neuron 2020; 108:919-936.e11. [PMID: 32976770 PMCID: PMC7736499 DOI: 10.1016/j.neuron.2020.08.030] [Citation(s) in RCA: 124] [Impact Index Per Article: 31.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Revised: 06/14/2020] [Accepted: 08/28/2020] [Indexed: 02/07/2023]
Abstract
Extrasynaptic actions of glutamate are limited by high-affinity transporters expressed by perisynaptic astroglial processes (PAPs): this helps maintain point-to-point transmission in excitatory circuits. Memory formation in the brain is associated with synaptic remodeling, but how this affects PAPs and therefore extrasynaptic glutamate actions is poorly understood. Here, we used advanced imaging methods, in situ and in vivo, to find that a classical synaptic memory mechanism, long-term potentiation (LTP), triggers withdrawal of PAPs from potentiated synapses. Optical glutamate sensors combined with patch-clamp and 3D molecular localization reveal that LTP induction thus prompts spatial retreat of astroglial glutamate transporters, boosting glutamate spillover and NMDA-receptor-mediated inter-synaptic cross-talk. The LTP-triggered PAP withdrawal involves NKCC1 transporters and the actin-controlling protein cofilin but does not depend on major Ca2+-dependent cascades in astrocytes. We have therefore uncovered a mechanism by which a memory trace at one synapse could alter signal handling by multiple neighboring connections.
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Affiliation(s)
- Christian Henneberger
- UCL Queen Square Institute of Neurology, University College London, London WC1N 3BG, UK; Institute of Cellular Neurosciences, Medical Faculty, University of Bonn, 53127 Bonn, Germany; German Center for Neurodegenerative Diseases (DZNE), 53175 Bonn, Germany.
| | - Lucie Bard
- UCL Queen Square Institute of Neurology, University College London, London WC1N 3BG, UK
| | - Aude Panatier
- INSERM U1215, Neurocentre Magendie, 33000 Bordeaux, France; Université de Bordeaux, 33000 Bordeaux, France; Interdisciplinary Institute for Neuroscience, CNRS UMR 5297, 33000 Bordeaux, France
| | - James P Reynolds
- UCL Queen Square Institute of Neurology, University College London, London WC1N 3BG, UK
| | - Olga Kopach
- UCL Queen Square Institute of Neurology, University College London, London WC1N 3BG, UK
| | | | - Daniel Minge
- Institute of Cellular Neurosciences, Medical Faculty, University of Bonn, 53127 Bonn, Germany
| | - Michel K Herde
- Institute of Cellular Neurosciences, Medical Faculty, University of Bonn, 53127 Bonn, Germany
| | - Stefanie Anders
- Institute of Cellular Neurosciences, Medical Faculty, University of Bonn, 53127 Bonn, Germany
| | - Igor Kraev
- Life Sciences, The Open University, Milton Keynes MK7 6AA, UK
| | - Janosch P Heller
- UCL Queen Square Institute of Neurology, University College London, London WC1N 3BG, UK
| | - Sylvain Rama
- UCL Queen Square Institute of Neurology, University College London, London WC1N 3BG, UK
| | - Kaiyu Zheng
- UCL Queen Square Institute of Neurology, University College London, London WC1N 3BG, UK
| | - Thomas P Jensen
- UCL Queen Square Institute of Neurology, University College London, London WC1N 3BG, UK
| | | | - Colin J Jackson
- Research School of Chemistry, Australian National University, Acton, ACT 2601, Australia
| | - Harald Janovjak
- Institute of Science and Technology Austria, 3400 Klosterneuburg, Austria; EMBL Australia, Australian Regenerative Medicine Institute, Faculty of Medicine, Nursing and Health Science, Monash University, Melbourne, VIC 3800, Australia
| | - Ole Petter Ottersen
- Institute of Basic Medical Sciences, University of Oslo, 0317 Oslo, Norway; Karolinska Institutet, 171 77 Stockholm, Sweden
| | | | - Stephane H R Oliet
- INSERM U1215, Neurocentre Magendie, 33000 Bordeaux, France; Université de Bordeaux, 33000 Bordeaux, France
| | | | - U Valentin Nägerl
- Université de Bordeaux, 33000 Bordeaux, France; Interdisciplinary Institute for Neuroscience, CNRS UMR 5297, 33000 Bordeaux, France.
| | - Dmitri A Rusakov
- UCL Queen Square Institute of Neurology, University College London, London WC1N 3BG, UK.
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40
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Caudal LC, Gobbo D, Scheller A, Kirchhoff F. The Paradox of Astroglial Ca 2 + Signals at the Interface of Excitation and Inhibition. Front Cell Neurosci 2020; 14:609947. [PMID: 33324169 PMCID: PMC7726216 DOI: 10.3389/fncel.2020.609947] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Accepted: 11/03/2020] [Indexed: 12/15/2022] Open
Abstract
Astroglial networks constitute a non-neuronal communication system in the brain and are acknowledged modulators of synaptic plasticity. A sophisticated set of transmitter receptors in combination with distinct secretion mechanisms enables astrocytes to sense and modulate synaptic transmission. This integrative function evolved around intracellular Ca2+ signals, by and large considered as the main indicator of astrocyte activity. Regular brain physiology meticulously relies on the constant reciprocity of excitation and inhibition (E/I). Astrocytes are metabolically, physically, and functionally associated to the E/I convergence. Metabolically, astrocytes provide glutamine, the precursor of both major neurotransmitters governing E/I in the central nervous system (CNS): glutamate and γ-aminobutyric acid (GABA). Perisynaptic astroglial processes are structurally and functionally associated with the respective circuits throughout the CNS. Astonishingly, in astrocytes, glutamatergic as well as GABAergic inputs elicit similar rises in intracellular Ca2+ that in turn can trigger the release of glutamate and GABA as well. Paradoxically, as gliotransmitters, these two molecules can thus strengthen, weaken or even reverse the input signal. Therefore, the net impact on neuronal network function is often convoluted and cannot be simply predicted by the nature of the stimulus itself. In this review, we highlight the ambiguity of astrocytes on discriminating and affecting synaptic activity in physiological and pathological state. Indeed, aberrant astroglial Ca2+ signaling is a key aspect of pathological conditions exhibiting compromised network excitability, such as epilepsy. Here, we gather recent evidence on the complexity of astroglial Ca2+ signals in health and disease, challenging the traditional, neuro-centric concept of segregating E/I, in favor of a non-binary, mutually dependent perspective on glutamatergic and GABAergic transmission.
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Affiliation(s)
- Laura C Caudal
- Department of Molecular Physiology, Center for Integrative Physiology and Molecular Medicine, University of Saarland, Homburg, Germany
| | - Davide Gobbo
- Department of Molecular Physiology, Center for Integrative Physiology and Molecular Medicine, University of Saarland, Homburg, Germany
| | - Anja Scheller
- Department of Molecular Physiology, Center for Integrative Physiology and Molecular Medicine, University of Saarland, Homburg, Germany
| | - Frank Kirchhoff
- Department of Molecular Physiology, Center for Integrative Physiology and Molecular Medicine, University of Saarland, Homburg, Germany
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41
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Cho J, Huh Y. Astrocytic Calcium Dynamics Along the Pain Pathway. Front Cell Neurosci 2020; 14:594216. [PMID: 33192331 PMCID: PMC7596274 DOI: 10.3389/fncel.2020.594216] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Accepted: 09/14/2020] [Indexed: 12/30/2022] Open
Abstract
Astrocytes, once thought to be passive cells merely filling the space between neurons in the nervous system, are receiving attention as active modulators of the brain and spinal cord physiology by providing nutrients, maintaining homeostasis, and modulating synaptic transmission. Accumulating evidence indicates that astrocytes are critically involved in chronic pain regulation. Injury induces astrocytes to become reactive, and recent studies suggest that reactive astrocytes can have either neuroprotective or neurodegenerative effects. While the exact mechanisms underlying the transition from resting astrocytes to reactive astrocytes remain unknown, astrocytic calcium increase, coordinated by inflammatory molecules, has been suggested to trigger this transition. In this mini review article, we will discuss the roles of astrocytic calcium, channels contributing to calcium dynamics in astrocytes, astrocyte activations along the pain pathway, and possible relationships between astrocytic calcium dynamics and chronic pain.
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Affiliation(s)
- Jeiwon Cho
- Brain and Cognitive Science, Scranton College, Ewha Womans University, Seoul, South Korea
| | - Yeowool Huh
- Department of Medical Science, College of Medicine, Catholic Kwandong University, Incheon, South Korea.,Translational Brain Research Center, Catholic Kwandong University, International St. Mary's Hospital, Incheon, South Korea
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A Computational Model to Investigate GABA-Activated Astrocyte Modulation of Neuronal Excitation. COMPUTATIONAL AND MATHEMATICAL METHODS IN MEDICINE 2020; 2020:8750167. [PMID: 33014120 PMCID: PMC7512075 DOI: 10.1155/2020/8750167] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/26/2020] [Revised: 08/14/2020] [Accepted: 08/28/2020] [Indexed: 11/18/2022]
Abstract
Gamma-aminobutyric acid (GABA) is critical for proper neural network function and can activate astrocytes to induce neuronal excitability; however, the mechanism by which astrocytes transform inhibitory signaling to excitatory enhancement remains unclear. Computational modeling can be a powerful tool to provide further understanding of how GABA-activated astrocytes modulate neuronal excitation. In the present study, we implemented a biophysical neuronal network model to investigate the effects of astrocytes on excitatory pre- and postsynaptic terminals following exposure to increasing concentrations of external GABA. The model completely describes the effects of GABA on astrocytes and excitatory presynaptic terminals within the framework of glutamatergic gliotransmission according to neurophysiological findings. Utilizing this model, our results show that astrocytes can rapidly respond to incoming GABA by inducing Ca2+ oscillations and subsequent gliotransmitter glutamate release. Elevation in GABA concentrations not only naturally decreases neuronal spikes but also enhances astrocytic glutamate release, which leads to an increase in astrocyte-mediated presynaptic release and postsynaptic slow inward currents. Neuronal excitation induced by GABA-activated astrocytes partly counteracts the inhibitory effect of GABA. Overall, the model helps to increase knowledge regarding the involvement of astrocytes in neuronal regulation using simulated bath perfusion of GABA, which may be useful for exploring the effects of GABA-type antiepileptic drugs.
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43
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Felix L, Delekate A, Petzold GC, Rose CR. Sodium Fluctuations in Astroglia and Their Potential Impact on Astrocyte Function. Front Physiol 2020; 11:871. [PMID: 32903427 PMCID: PMC7435049 DOI: 10.3389/fphys.2020.00871] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Accepted: 06/29/2020] [Indexed: 12/12/2022] Open
Abstract
Astrocytes are the main cell type responsible for the regulation of brain homeostasis, including the maintenance of ion gradients and neurotransmitter clearance. These processes are tightly coupled to changes in the intracellular sodium (Na+) concentration. While activation of the sodium-potassium-ATPase (NKA) in response to an elevation of extracellular K+ may decrease intracellular Na+, the cotransport of transmitters, such as glutamate, together with Na+ results in an increase in astrocytic Na+. This increase in intracellular Na+ can modulate, for instance, metabolic downstream pathways. Thereby, astrocytes are capable to react on a fast time scale to surrounding neuronal activity via intracellular Na+ fluctuations and adjust energy production to the demand of their environment. Beside the well-documented conventional roles of Na+ signaling mainly mediated through changes in its electrochemical gradient, several recent studies have identified more atypical roles for Na+, including protein interactions leading to changes in their biochemical activity or Na+-dependent regulation of gene expression. In this review, we will address both the conventional as well as the atypical functions of astrocytic Na+ signaling, presenting the role of transporters and channels involved and their implications for physiological processes in the central nervous system (CNS). We will also discuss how these important functions are affected under pathological conditions, including stroke and migraine. We postulate that Na+ is an essential player not only in the maintenance of homeostatic processes but also as a messenger for the fast communication between neurons and astrocytes, adjusting the functional properties of various cellular interaction partners to the needs of the surrounding network.
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Affiliation(s)
- Lisa Felix
- Institute of Neurobiology, Heinrich Heine University Duesseldorf, Duesseldorf, Germany
| | - Andrea Delekate
- German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany
| | - Gabor C Petzold
- German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany.,Division of Vascular Neurology, Department of Neurology, University Hospital Bonn, Bonn, Germany
| | - Christine R Rose
- Institute of Neurobiology, Heinrich Heine University Duesseldorf, Duesseldorf, Germany
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Ciappelloni S, Bouchet D, Dubourdieu N, Boué-Grabot E, Kellermayer B, Manso C, Marignier R, Oliet SHR, Tourdias T, Groc L. Aquaporin-4 Surface Trafficking Regulates Astrocytic Process Motility and Synaptic Activity in Health and Autoimmune Disease. Cell Rep 2020; 27:3860-3872.e4. [PMID: 31242419 DOI: 10.1016/j.celrep.2019.05.097] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Revised: 03/08/2019] [Accepted: 05/23/2019] [Indexed: 01/21/2023] Open
Abstract
Astrocytes constantly adapt their ramified morphology in order to support brain cell assemblies. Such plasticity is partly mediated by ion and water fluxes, which rely on the water channel aquaporin-4 (AQP4). The mechanism by which this channel locally contributes to process dynamics has remained elusive. Using a combination of single-molecule and calcium imaging approaches, we here investigated in hippocampal astrocytes the dynamic distribution of the AQP4 isoforms M1 and M23. Surface AQP4-M1 formed small aggregates that contrast with the large AQP4-M23 clusters that are enriched near glutamatergic synapses. Strikingly, stabilizing surface AQP4-M23 tuned the motility of astrocyte processes and favors glutamate synapse activity. Furthermore, human autoantibodies directed against AQP4 from neuromyelitis optica (NMO) patients impaired AQP4-M23 dynamic distribution and, consequently, astrocyte process and synaptic activity. Collectively, it emerges that the membrane dynamics of AQP4 isoform regulate brain cell assemblies in health and autoimmune brain disease targeting AQP4.
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Affiliation(s)
- Silvia Ciappelloni
- Interdisciplinary Institute for NeuroSciences, CNRS UMR 5297, 33077 Bordeaux, France; Université de Bordeaux, 33077 Bordeaux, France; INSERM U1215, Neurocentre Magendie, 33077 Bordeaux, France
| | - Delphine Bouchet
- Interdisciplinary Institute for NeuroSciences, CNRS UMR 5297, 33077 Bordeaux, France; Université de Bordeaux, 33077 Bordeaux, France
| | - Nadège Dubourdieu
- Université de Bordeaux, 33077 Bordeaux, France; INSERM U1215, Neurocentre Magendie, 33077 Bordeaux, France
| | - Eric Boué-Grabot
- Université de Bordeaux, 33077 Bordeaux, France; CNRS, Institut des Maladies Neurodégénératives, UMR 5293, 33000 Bordeaux, France
| | - Blanka Kellermayer
- Interdisciplinary Institute for NeuroSciences, CNRS UMR 5297, 33077 Bordeaux, France; Université de Bordeaux, 33077 Bordeaux, France
| | - Constance Manso
- Interdisciplinary Institute for NeuroSciences, CNRS UMR 5297, 33077 Bordeaux, France; Université de Bordeaux, 33077 Bordeaux, France
| | - Romain Marignier
- INSERM U1028, CNRS UMR 5292, Center for Research in Neuroscience of Lyon, Lyon, France
| | - Stéphane H R Oliet
- Université de Bordeaux, 33077 Bordeaux, France; INSERM U1215, Neurocentre Magendie, 33077 Bordeaux, France
| | - Thomas Tourdias
- Université de Bordeaux, 33077 Bordeaux, France; INSERM U1215, Neurocentre Magendie, 33077 Bordeaux, France
| | - Laurent Groc
- Interdisciplinary Institute for NeuroSciences, CNRS UMR 5297, 33077 Bordeaux, France; Université de Bordeaux, 33077 Bordeaux, France.
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Larramona-Arcas R, González-Arias C, Perea G, Gutiérrez A, Vitorica J, García-Barrera T, Gómez-Ariza JL, Pascua-Maestro R, Ganfornina MD, Kara E, Hudry E, Martinez-Vicente M, Vila M, Galea E, Masgrau R. Sex-dependent calcium hyperactivity due to lysosomal-related dysfunction in astrocytes from APOE4 versus APOE3 gene targeted replacement mice. Mol Neurodegener 2020; 15:35. [PMID: 32517777 PMCID: PMC7285605 DOI: 10.1186/s13024-020-00382-8] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Accepted: 05/25/2020] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND The apolipoprotein E (APOE) gene exists in three isoforms in humans: APOE2, APOE3 and APOE4. APOE4 causes structural and functional alterations in normal brains, and is the strongest genetic risk factor of the sporadic form of Alzheimer's disease (LOAD). Research on APOE4 has mainly focused on the neuronal damage caused by defective cholesterol transport and exacerbated amyloid-β and Tau pathology. The impact of APOE4 on non-neuronal cell functions has been overlooked. Astrocytes, the main producers of ApoE in the healthy brain, are building blocks of neural circuits, and Ca2+ signaling is the basis of their excitability. Because APOE4 modifies membrane-lipid composition, and lipids regulate Ca2+ channels, we determined whether APOE4 dysregulates Ca2+signaling in astrocytes. METHODS Ca2+ signals were recorded in astrocytes in hippocampal slices from APOE3 and APOE4 gene targeted replacement male and female mice using Ca2+ imaging. Mechanistic analyses were performed in immortalized astrocytes. Ca2+ fluxes were examined with pharmacological tools and Ca2+ probes. APOE3 and APOE4 expression was manipulated with GFP-APOE vectors and APOE siRNA. Lipidomics of lysosomal and whole-membranes were also performed. RESULTS We found potentiation of ATP-elicited Ca2+responses in APOE4 versus APOE3 astrocytes in male, but not female, mice. The immortalized astrocytes modeled the male response, and showed that Ca2+ hyperactivity associated with APOE4 is caused by dysregulation of Ca2+ handling in lysosomal-enriched acidic stores, and is reversed by the expression of APOE3, but not of APOE4, pointing to loss of function due to APOE4 malfunction. Moreover, immortalized APOE4 astrocytes are refractory to control of Ca2+ fluxes by extracellular lipids, and present distinct lipid composition in lysosomal and plasma membranes. CONCLUSIONS Immortalized APOE4 versus APOE3 astrocytes present: increased Ca2+ excitability due to lysosome dysregulation, altered membrane lipidomes and intracellular cholesterol distribution, and impaired modulation of Ca2+ responses upon changes in extracellular lipids. Ca2+ hyperactivity associated with APOE4 is found in astrocytes from male, but not female, targeted replacement mice. The study suggests that, independently of Aβ and Tau pathologies, altered astrocyte excitability might contribute to neural-circuit hyperactivity depending on APOE allele, sex and lipids, and supports lysosome-targeted therapies to rescue APOE4 phenotypes in LOAD.
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Affiliation(s)
- Raquel Larramona-Arcas
- Unitat de Bioquímica de Medicina, Departament de Bioquímica i Biologia Molecular, and, Institut de Neurociències (INc), Facultat de Medicina, Universitat Autònoma de Barcelona, 08193 Cerdanyola del Vallès, Barcelona, Catalonia Spain
| | - Candela González-Arias
- Cajal Institute, Consejo Superior de Investigaciones Científicas (CSIC), 28002 Madrid, Spain
| | - Gertrudis Perea
- Cajal Institute, Consejo Superior de Investigaciones Científicas (CSIC), 28002 Madrid, Spain
| | - Antonia Gutiérrez
- Departamento de Biología Celular, Genética y Fisiología, Facultad de Ciencias, Instituto de Investigación Biomedica de Málaga (IBIMA), Universidad de Málaga, 29071 Málaga, Spain
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), 28031 Madrid, Spain
| | - Javier Vitorica
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), 28031 Madrid, Spain
- Departamento de Bioquímica y Biología Molecular, Facultad de Farmacia, Universidad de Sevilla, Instituto de Biomedicina de Sevilla (IBiS)-Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, 41012 Sevilla, Spain
| | - Tamara García-Barrera
- Departamento de Química, Facultad de Ciencias Experimentales, Campus de El Carmen, Centro de Investigación en Recursos Naturales, Salud y Medio Ambiente (RENSMA), Universidad de Huelva, 21007 Huelva, Spain
| | - José Luis Gómez-Ariza
- Departamento de Química, Facultad de Ciencias Experimentales, Campus de El Carmen, Centro de Investigación en Recursos Naturales, Salud y Medio Ambiente (RENSMA), Universidad de Huelva, 21007 Huelva, Spain
| | - Raquel Pascua-Maestro
- Departamento de Bioquímica y Biología Molecular y Fisiología, Instituto de Biología y Genética Molecular, Universidad de Valladolid-CSIC, 43007 Valladolid, Spain
| | - María Dolores Ganfornina
- Departamento de Bioquímica y Biología Molecular y Fisiología, Instituto de Biología y Genética Molecular, Universidad de Valladolid-CSIC, 43007 Valladolid, Spain
| | - Eleanna Kara
- Alzheimer’s Disease Research Laboratory, MassGeneral Institute for Neurodegenerative Disease, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA 02129 USA
- Present Address: Institute of Neuropathology, University Hospital of Zurich, 8091 Zurich, Switzerland
| | - Eloise Hudry
- Alzheimer’s Disease Research Laboratory, MassGeneral Institute for Neurodegenerative Disease, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA 02129 USA
| | - Marta Martinez-Vicente
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), 28031 Madrid, Spain
- Neurodegenerative Diseases Research Group, Vall d’Hebron Research Institute (VHIR), 08035 Barcelona, Spain
| | - Miquel Vila
- Unitat de Bioquímica de Medicina, Departament de Bioquímica i Biologia Molecular, and, Institut de Neurociències (INc), Facultat de Medicina, Universitat Autònoma de Barcelona, 08193 Cerdanyola del Vallès, Barcelona, Catalonia Spain
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), 28031 Madrid, Spain
- Neurodegenerative Diseases Research Group, Vall d’Hebron Research Institute (VHIR), 08035 Barcelona, Spain
- ICREA, Passeig Lluís Companys 23, 08010 Barcelona, Catalonia Spain
| | - Elena Galea
- Unitat de Bioquímica de Medicina, Departament de Bioquímica i Biologia Molecular, and, Institut de Neurociències (INc), Facultat de Medicina, Universitat Autònoma de Barcelona, 08193 Cerdanyola del Vallès, Barcelona, Catalonia Spain
- ICREA, Passeig Lluís Companys 23, 08010 Barcelona, Catalonia Spain
| | - Roser Masgrau
- Unitat de Bioquímica de Medicina, Departament de Bioquímica i Biologia Molecular, and, Institut de Neurociències (INc), Facultat de Medicina, Universitat Autònoma de Barcelona, 08193 Cerdanyola del Vallès, Barcelona, Catalonia Spain
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Sáez JC, Vargas AA, Hernández DE, Ortiz FC, Giaume C, Orellana JA. Permeation of Molecules through Astroglial Connexin 43 Hemichannels Is Modulated by Cytokines with Parameters Depending on the Permeant Species. Int J Mol Sci 2020; 21:ijms21113970. [PMID: 32492823 PMCID: PMC7312936 DOI: 10.3390/ijms21113970] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 05/25/2020] [Accepted: 05/29/2020] [Indexed: 12/11/2022] Open
Abstract
Recent studies indicate that connexin hemichannels do not act as freely permeable non-selective pores, but they select permeants in an isoform-specific manner with cooperative, competitive and saturable kinetics. The aim of this study was to investigate whether the treatment with a mixture of IL-1β plus TNF-α, a well-known pro-inflammatory condition that activates astroglial connexin 43 (Cx43) hemichannels, could alter their permeability to molecules. We found that IL-1β plus TNF-α left-shifted the dye uptake rate vs. dye concentration relationship for Etd and 2-NBDG, but the opposite took place for DAPI or YO-PRO-1, whereas no alterations were observed for Prd. The latter modifications were accompanied of changes in Kd (Etd, DAPI, YO-PRO-1 or 2-NBDG) and Hill coefficients (Etd and YO-PRO-1), but not in alterations of Vmax. We speculate that IL-1β plus TNF-α may distinctively affect the binding sites to permeants in astroglial Cx43 hemichannels rather than their number in the cell surface. Alternatively, IL-1β plus TNF-α could induce the production of endogenous permeants that may favor or compete for in the pore-lining residues of Cx43 hemichannels. Future studies shall elucidate whether the differential ionic/molecule permeation of Cx43 hemichannels in astrocytes could impact their communication with neurons in the normal and inflamed nervous system.
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Affiliation(s)
- Juan C. Sáez
- Departamento de Fisiología, Pontificia Universidad Católica de Chile, Santiago 8330024, Chile; (J.C.S.); (D.E.H.)
- Instituto de Neurociencias, Centro Interdisciplinario de Neurociencias de Valparaíso, Universidad de Valparaíso, Valparaíso 2381850, Chile
| | - Aníbal A. Vargas
- Instituto de Ciencias de la Salud, Universidad de O′Higgins, Rancagua 2820000, Chile;
| | - Diego E. Hernández
- Departamento de Fisiología, Pontificia Universidad Católica de Chile, Santiago 8330024, Chile; (J.C.S.); (D.E.H.)
| | - Fernando C. Ortiz
- Mechanisms on Myelin Formation and Repair Laboratory, Instituto de Ciencias Biomédicas, Facultad de Ciencias de la Salud, Universidad Autónoma de Chile, Santiago 8910060, Chile;
| | - Christian Giaume
- Center for Interdisciplinary Research in Biology (CIRB), College de France, CNRS, INSERM, PSL Research University, 75005 Paris, France;
| | - Juan A. Orellana
- Departamento de Neurología, Escuela de Medicina and Centro Interdisciplinario de Neurociencias, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago 8330024, Chile
- Correspondence: ; Tel.: +56-2-968399128
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Gollihue J, Norris C. Astrocyte mitochondria: Central players and potential therapeutic targets for neurodegenerative diseases and injury. Ageing Res Rev 2020; 59:101039. [PMID: 32105849 DOI: 10.1016/j.arr.2020.101039] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Revised: 01/23/2020] [Accepted: 02/23/2020] [Indexed: 01/16/2023]
Abstract
Mitochondrial function has long been the focus of many therapeutic strategies for ameliorating age-related neurodegeneration and cognitive decline. Historically, the role of mitochondria in non-neuronal cell types has been overshadowed by neuronal mitochondria, which are responsible for the bulk of oxidative metabolism in the brain. Despite this neuronal bias, mitochondrial function in glial cells, particularly astrocytes, is increasingly recognized to play crucial roles in overall brain metabolism, synaptic transmission, and neuronal protection. Changes in astrocytic mitochondrial function appear to be intimately linked to astrocyte activation/reactivity found in most all age-related neurodegenerative diseases. Here, we address the importance of mitochondrial function to astrocyte signaling and consider how mitochondria could contribute to both the detrimental and protective properties of activated astrocytes. Strategies for protecting astrocytic mitochondrial function, promoting bidirectional transfer of mitochondria between astrocytes and neurons, and transplanting healthy mitochondria to diseased nervous tissue are also discussed.
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Structural basis of astrocytic Ca 2+ signals at tripartite synapses. Nat Commun 2020; 11:1906. [PMID: 32312988 PMCID: PMC7170846 DOI: 10.1038/s41467-020-15648-4] [Citation(s) in RCA: 86] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Accepted: 03/19/2020] [Indexed: 02/07/2023] Open
Abstract
Astrocytic Ca2+ signals can be fast and local, supporting the idea that astrocytes have the ability to regulate single synapses. However, the anatomical basis of such specific signaling remains unclear, owing to difficulties in resolving the spongiform domain of astrocytes where most tripartite synapses are located. Using 3D-STED microscopy in living organotypic brain slices, we imaged the spongiform domain of astrocytes and observed a reticular meshwork of nodes and shafts that often formed loop-like structures. These anatomical features were also observed in acute hippocampal slices and in barrel cortex in vivo. The majority of dendritic spines were contacted by nodes and their sizes were correlated. FRAP experiments and Ca2+ imaging showed that nodes were biochemical compartments and Ca2+ microdomains. Mapping astrocytic Ca2+ signals onto STED images of nodes and dendritic spines showed they were associated with individual synapses. Here, we report on the nanoscale organization of astrocytes, identifying nodes as a functional astrocytic component of tripartite synapses that may enable synapse-specific communication between neurons and astrocytes. Astrocytic Ca2+ signals can be fast and local, supporting the idea that astrocytes have the ability to regulate single synapses. Here, the authors report the organization of astrocytes at nanoscale level and identify nodes as a functional astrocytic component of tripartite synapses.
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49
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Pestana F, Edwards-Faret G, Belgard TG, Martirosyan A, Holt MG. No Longer Underappreciated: The Emerging Concept of Astrocyte Heterogeneity in Neuroscience. Brain Sci 2020; 10:brainsci10030168. [PMID: 32183137 PMCID: PMC7139801 DOI: 10.3390/brainsci10030168] [Citation(s) in RCA: 55] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Revised: 03/02/2020] [Accepted: 03/05/2020] [Indexed: 12/18/2022] Open
Abstract
Astrocytes are ubiquitous in the central nervous system (CNS). These cells possess thousands of individual processes, which extend out into the neuropil, interacting with neurons, other glia and blood vessels. Paralleling the wide diversity of their interactions, astrocytes have been reported to play key roles in supporting CNS structure, metabolism, blood-brain-barrier formation and control of vascular blood flow, axon guidance, synapse formation and modulation of synaptic transmission. Traditionally, astrocytes have been studied as a homogenous group of cells. However, recent studies have uncovered a surprising degree of heterogeneity in their development and function, in both the healthy and diseased brain. A better understanding of astrocyte heterogeneity is urgently needed to understand normal brain function, as well as the role of astrocytes in response to injury and disease.
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Affiliation(s)
- Francisco Pestana
- Laboratory of Glia Biology, VIB-KU Leuven Center for Brain and Disease Research, 3000 Leuven, Belgium;
| | - Gabriela Edwards-Faret
- Laboratory of Neuronal Wiring, VIB-KU Leuven Center for Brain and Disease Research, 3000 Leuven, Belgium;
- Life & Medical Sciences (LIMES) Institute, Faculty of Mathematics and Natural Sciences, University of Bonn, 53115 Bonn, Germany
| | | | - Araks Martirosyan
- Laboratory of Glia Biology, VIB-KU Leuven Center for Brain and Disease Research, 3000 Leuven, Belgium;
- Correspondence: (A.M.); (M.G.H.); Tel.: +32-16-37-31-27 (M.G.H.)
| | - Matthew G. Holt
- Laboratory of Glia Biology, VIB-KU Leuven Center for Brain and Disease Research, 3000 Leuven, Belgium;
- Leuven Brain Institute, KU Leuven, 3000 Leuven, Belgium
- Correspondence: (A.M.); (M.G.H.); Tel.: +32-16-37-31-27 (M.G.H.)
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50
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Heller JP, Odii T, Zheng K, Rusakov DA. Imaging tripartite synapses using super-resolution microscopy. Methods 2020; 174:81-90. [PMID: 31153907 PMCID: PMC7144327 DOI: 10.1016/j.ymeth.2019.05.024] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Revised: 05/03/2019] [Accepted: 05/28/2019] [Indexed: 01/02/2023] Open
Abstract
Astroglia are vital facilitators of brain development, homeostasis, and metabolic support. In addition, they are also essential to the formation and regulation of synaptic circuits. Due to the extraordinary complex, nanoscopic morphology of astrocytes, the underlying cellular mechanisms have been poorly understood. In particular, fine astrocytic processes that can be found in the vicinity of synapses have been difficult to study using traditional imaging techniques. Here, we describe a 3D three-colour super-resolution microscopy approach to unravel the nanostructure of tripartite synapses. The method is based on the SMLM technique direct stochastic optical reconstruction microscopy (dSTORM) which uses conventional fluorophore-labelled antibodies. This approach enables reconstructing the nanoscale localisation of individual astrocytic glutamate transporter (GLT-1) molecules surrounding presynaptic (bassoon) and postsynaptic (Homer1) protein localisations in fixed mouse brain sections. However, the technique is readily adaptable to other types of targets and tissues.
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Affiliation(s)
- Janosch Peter Heller
- UCL Queen Square Institute of Neurology, University College London, London, United Kingdom; FutureNeuro Research Centre, Royal College of Surgeons in Ireland, Dublin, Ireland.
| | - Tuamoru Odii
- UCL Queen Square Institute of Neurology, University College London, London, United Kingdom; Department of Physiology, Faculty of Basic Medical Sciences, Alex Ekwueme Federal University Ndufu-Alike Ikwo, PMB 1010 Abakaliki, Nigeria
| | - Kaiyu Zheng
- UCL Queen Square Institute of Neurology, University College London, London, United Kingdom
| | - Dmitri A Rusakov
- UCL Queen Square Institute of Neurology, University College London, London, United Kingdom.
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