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Sung Y, Gotina L, Kim KH, Lee JY, Shin S, Aziz H, Kang DM, Liu X, Hong NK, Lee HG, Lee JS, Ku H, Jeong C, Pae AN, Lim S, Chang YT, Kim YK. NeuM: A Neuron-Selective Probe Incorporates into Live Neuronal Membranes via Enhanced Clathrin-Mediated Endocytosis in Primary Neurons. Angew Chem Int Ed Engl 2024; 63:e202312942. [PMID: 38062619 DOI: 10.1002/anie.202312942] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2023] [Indexed: 01/10/2024]
Abstract
The development of a small-molecule probe designed to selectively target neurons would enhance the exploration of intricate neuronal structures and functions. Among such probes, NeuO stands out as the pioneer and has gained significant traction in the field of research. Nevertheless, neither the mechanism behind neuron-selectivity nor the cellular localization has been determined. Here, we introduce NeuM, a derivative of NeuO, designed to target neuronal cell membranes. Furthermore, we elucidate the mechanism behind the selective neuronal membrane trafficking that distinguishes neurons. In an aqueous buffer, NeuM autonomously assembles into micellar structures, leading to the quenching of its fluorescence (Φ=0.001). Upon exposure to neurons, NeuM micelles were selectively internalized into neuronal endosomes via clathrin-mediated endocytosis. Through the endocytic recycling pathway, NeuM micelles integrate into neuronal membrane, dispersing fluorescent NeuM molecules in the membrane (Φ=0.61). Molecular dynamics simulations demonstrated that NeuM, in comparison to NeuO, possesses optimal lipophilicity and molecular length, facilitating its stable incorporation into phospholipid layers. The stable integration of NeuM within neuronal membrane allows the prolonged monitoring of neurons, as well as the visualization of intricate neuronal structures.
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Affiliation(s)
- Yoonsik Sung
- Center for Brain Disorders, Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea
| | - Lizaveta Gotina
- Center for Brain Disorders, Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea
- Division of Bio-Medical Science & Technology, KIST School, Korea University of Science and Technology (UST), Seoul, 02792, Republic of Korea
| | - Kyu Hyeon Kim
- Center for Brain Disorders, Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea
- Division of Bio-Medical Science & Technology, KIST School, Korea University of Science and Technology (UST), Seoul, 02792, Republic of Korea
| | - Jung Yeol Lee
- Department of Chemistry, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
| | - Seulgi Shin
- Center for Brain Disorders, Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea
| | - Hira Aziz
- Center for Brain Disorders, Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea
- Division of Bio-Medical Science & Technology, KIST School, Korea University of Science and Technology (UST), Seoul, 02792, Republic of Korea
| | - Dong Min Kang
- Center for Brain Disorders, Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea
- Department of Life Sciences, Korea University, Seoul, 02841, Republic of Korea
| | - Xiao Liu
- Department of Chemistry, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
| | - Na-Kyeong Hong
- Department of Chemistry, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
| | - Hong-Guen Lee
- Department of Chemistry, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
| | - Jun-Seok Lee
- Department of Pharmacology, Korea University College of Medicine, Seoul, 02841, Republic of Korea
| | - Hyeyeong Ku
- Chemical and Biological Integrative Research Center, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea
- KHU-KIST Department of Converging Science and Technology, Kyung Hee University, Seoul, 02447, Republic of Korea
| | - Cherlhyun Jeong
- Division of Bio-Medical Science & Technology, KIST School, Korea University of Science and Technology (UST), Seoul, 02792, Republic of Korea
- Chemical and Biological Integrative Research Center, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea
| | - Ae Nim Pae
- Center for Brain Disorders, Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea
- Division of Bio-Medical Science & Technology, KIST School, Korea University of Science and Technology (UST), Seoul, 02792, Republic of Korea
| | - Sungsu Lim
- Center for Brain Disorders, Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea
| | - Young-Tae Chang
- Department of Chemistry, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
| | - Yun Kyung Kim
- Center for Brain Disorders, Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea
- Division of Bio-Medical Science & Technology, KIST School, Korea University of Science and Technology (UST), Seoul, 02792, Republic of Korea
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2
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Kelly P, Sanchez-Mico MV, Hou SS, Whiteman S, Russ A, Hudry E, Arbel-Ornath M, Greenberg SM, Bacskai BJ. Neuronally Derived Soluble Abeta Evokes Cell-Wide Astrocytic Calcium Dysregulation in Absence of Amyloid Plaques in Vivo. J Neurosci 2023; 43:4926-4940. [PMID: 37236808 PMCID: PMC10312057 DOI: 10.1523/jneurosci.1988-22.2023] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2022] [Revised: 03/22/2023] [Accepted: 04/27/2023] [Indexed: 05/28/2023] Open
Abstract
The key pathologic entities driving the destruction of synaptic function and integrity during the evolution of Alzheimer's disease (AD) remain elusive. Astrocytes are structurally and functionally integrated within synaptic and vascular circuitry and use calcium-based physiology to modulate basal synaptic transmission, vascular dynamics, and neurovascular coupling, which are central to AD pathogenesis. We used high-resolution multiphoton imaging to quantify all endogenous calcium signaling arising spontaneously throughout astrocytic somata, primary processes, fine processes, and capillary endfeet in the brain of awake APP/PS1 transgenic mice (11 male and 6 female mice). Endogenous calcium signaling within capillary endfeet, while surprisingly as active as astrocytic fine processes, was reduced ∼50% in the brain of awake APP/PS1 mice. Cortical astrocytes, in the presence of amyloid plaques in awake APP/PS1 mice, had a cell-wide increase in intracellular calcium associated with an increased frequency, amplitude, and duration of spontaneous calcium signaling. The cell-wide astrocytic calcium dysregulation was not directly related to distance to amyloid plaques. We could re-create the cell-wide intracellular calcium dysregulation in the absence of amyloid plaques following acute exposure to neuronally derived soluble Abeta from Tg2576 transgenic mice, in the living brain of male C57/Bl6 mice. Our findings highlight a role for astrocytic calcium pathophysiology in soluble-Abeta mediated neurodegenerative processes in AD. Additionally, therapeutic strategies aiming to protect astrocytic calcium physiology from soluble Abeta-mediated toxicity may need to pharmacologically enhance calcium signaling within the hypoactive capillary endfeet while reducing the hyperactivity of spontaneous calcium signaling throughout the rest of the astrocyte.SIGNIFICANCE STATEMENT Astrocytic calcium signaling is functionally involved in central pathologic processes of Alzheimer's disease. We quantified endogenous calcium signaling arising spontaneously in the brain of awake APP/PS1 mice, as general anesthesia suppressed astrocytic calcium signaling. Cell-wide astrocytic calcium dysregulation was not related to distance to amyloid plaques but mediated in part by neuronally derived soluble Abeta, supporting a role for astrocytes in soluble-Abeta mediated neurodegeneration. Spontaneous calcium signaling is largely compartmentalized and capillary endfeet were as active as fine processes but hypoactive in the presence of amyloid plaques, while the rest of the astrocyte became hyperactive. The cell-wide calcium pathophysiology in astrocytes may require a combination therapeutic strategy for hypoactive endfeet and astrocytic hyperactivity.
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Affiliation(s)
- Patricia Kelly
- Massachusetts General Hospital/Harvard Medical School, Charlestown, Massachusetts 02129
| | - Maria V Sanchez-Mico
- Massachusetts General Hospital/Harvard Medical School, Charlestown, Massachusetts 02129
| | - Steven S Hou
- Massachusetts General Hospital/Harvard Medical School, Charlestown, Massachusetts 02129
| | - Sara Whiteman
- Massachusetts General Hospital/Harvard Medical School, Charlestown, Massachusetts 02129
| | - Alyssa Russ
- Massachusetts General Hospital/Harvard Medical School, Charlestown, Massachusetts 02129
| | - Eloise Hudry
- Massachusetts General Hospital/Harvard Medical School, Charlestown, Massachusetts 02129
| | - Michal Arbel-Ornath
- Massachusetts General Hospital/Harvard Medical School, Charlestown, Massachusetts 02129
| | - Steven M Greenberg
- Massachusetts General Hospital/Harvard Medical School, Charlestown, Massachusetts 02129
| | - Brian J Bacskai
- Massachusetts General Hospital/Harvard Medical School, Charlestown, Massachusetts 02129
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3
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Untiet V, Beinlich FRM, Kusk P, Kang N, Ladrón-de-Guevara A, Song W, Kjaerby C, Andersen M, Hauglund N, Bojarowska Z, Sigurdsson B, Deng S, Hirase H, Petersen NC, Verkhratsky A, Nedergaard M. Astrocytic chloride is brain state dependent and modulates inhibitory neurotransmission in mice. Nat Commun 2023; 14:1871. [PMID: 37015909 PMCID: PMC10073105 DOI: 10.1038/s41467-023-37433-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Accepted: 03/15/2023] [Indexed: 04/06/2023] Open
Abstract
Information transfer within neuronal circuits depends on the balance and recurrent activity of excitatory and inhibitory neurotransmission. Chloride (Cl-) is the major central nervous system (CNS) anion mediating inhibitory neurotransmission. Astrocytes are key homoeostatic glial cells populating the CNS, although the role of these cells in regulating excitatory-inhibitory balance remains unexplored. Here we show that astrocytes act as a dynamic Cl- reservoir regulating Cl- homoeostasis in the CNS. We found that intracellular chloride concentration ([Cl-]i) in astrocytes is high and stable during sleep. In awake mice astrocytic [Cl-]i is lower and exhibits large fluctuation in response to both sensory input and motor activity. Optogenetic manipulation of astrocytic [Cl-]i directly modulates neuronal activity during locomotion or whisker stimulation. Astrocytes thus serve as a dynamic source of extracellular Cl- available for GABAergic transmission in awake mice, which represents a mechanism for modulation of the inhibitory tone during sustained neuronal activity.
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Affiliation(s)
- Verena Untiet
- Division of Glial Disease and Therapeutics, Center for Translational Neuromedicine, University of Copenhagen, 2200, Copenhagen, Denmark.
| | - Felix R M Beinlich
- Division of Glial Disease and Therapeutics, Center for Translational Neuromedicine, University of Copenhagen, 2200, Copenhagen, Denmark
| | - Peter Kusk
- Division of Glial Disease and Therapeutics, Center for Translational Neuromedicine, University of Copenhagen, 2200, Copenhagen, Denmark
| | - Ning Kang
- Division of Glial Disease and Therapeutics, Center for Translational Neuromedicine, Department of Neurosurgery, University of Rochester Medical Center, Rochester, NY, 14642, USA
| | - Antonio Ladrón-de-Guevara
- Division of Glial Disease and Therapeutics, Center for Translational Neuromedicine, Department of Neurosurgery, University of Rochester Medical Center, Rochester, NY, 14642, USA
- Department of Biomedical Engineering, University of Rochester, Rochester, NY, 14627, USA
| | - Wei Song
- Division of Glial Disease and Therapeutics, Center for Translational Neuromedicine, Department of Neurosurgery, University of Rochester Medical Center, Rochester, NY, 14642, USA
| | - Celia Kjaerby
- Division of Glial Disease and Therapeutics, Center for Translational Neuromedicine, University of Copenhagen, 2200, Copenhagen, Denmark
| | - Mie Andersen
- Division of Glial Disease and Therapeutics, Center for Translational Neuromedicine, University of Copenhagen, 2200, Copenhagen, Denmark
| | - Natalie Hauglund
- Division of Glial Disease and Therapeutics, Center for Translational Neuromedicine, University of Copenhagen, 2200, Copenhagen, Denmark
| | - Zuzanna Bojarowska
- Division of Glial Disease and Therapeutics, Center for Translational Neuromedicine, University of Copenhagen, 2200, Copenhagen, Denmark
| | - Björn Sigurdsson
- Division of Glial Disease and Therapeutics, Center for Translational Neuromedicine, University of Copenhagen, 2200, Copenhagen, Denmark
| | - Saiyue Deng
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, P.R. China
| | - Hajime Hirase
- Division of Glial Disease and Therapeutics, Center for Translational Neuromedicine, University of Copenhagen, 2200, Copenhagen, Denmark
| | - Nicolas C Petersen
- Division of Glial Disease and Therapeutics, Center for Translational Neuromedicine, University of Copenhagen, 2200, Copenhagen, Denmark
| | - Alexei Verkhratsky
- Division of Glial Disease and Therapeutics, Center for Translational Neuromedicine, University of Copenhagen, 2200, Copenhagen, Denmark.
- Faculty of Biology, Medicine and Health, The University of Manchester, Oxford Rd, Manchester, M13 9PL, UK.
- Achucarro Centre for Neuroscience, IKERBASQUE, Basque Foundation for Science, Plaza Euskadi 5, 48009, Bilbao, Spain.
| | - Maiken Nedergaard
- Division of Glial Disease and Therapeutics, Center for Translational Neuromedicine, University of Copenhagen, 2200, Copenhagen, Denmark.
- Division of Glial Disease and Therapeutics, Center for Translational Neuromedicine, Department of Neurosurgery, University of Rochester Medical Center, Rochester, NY, 14642, USA.
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4
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Li T, Li D, Wei Q, Shi M, Xiang J, Gao R, Chen C, Xu ZX. Dissecting the neurovascular unit in physiology and Alzheimer's disease: Functions, imaging tools and genetic mouse models. Neurobiol Dis 2023; 181:106114. [PMID: 37023830 DOI: 10.1016/j.nbd.2023.106114] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Revised: 03/22/2023] [Accepted: 04/02/2023] [Indexed: 04/08/2023] Open
Abstract
The neurovascular unit (NVU) plays an essential role in regulating neurovascular coupling, which refers to the communication between neurons, glia, and vascular cells to control the supply of oxygen and nutrients in response to neural activity. Cellular elements of the NVU coordinate to establish an anatomical barrier to separate the central nervous system from the milieu of the periphery system, restricting the free movement of substances from the blood to the brain parenchyma and maintaining central nervous system homeostasis. In Alzheimer's disease, amyloid-β deposition impairs the normal functions of NVU cellular elements, thus accelerating the disease progression. Here, we aim to describe the current knowledge of the NVU cellular elements, including endothelial cells, pericytes, astrocytes, and microglia, in regulating the blood-brain barrier integrity and functions in physiology as well as alterations encountered in Alzheimer's disease. Furthermore, the NVU functions as a whole, therefore specific labeling and targeting NVU components in vivo enable us to understand the mechanism mediating cellular communication. We review approaches including commonly used fluorescent dyes, genetic mouse models, and adeno-associated virus vectors for imaging and targeting NVU cellular elements in vivo.
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Affiliation(s)
- Tiantian Li
- State Key Laboratory of Medical Neurobiology, MOE Frontiers Center for Brain Science, and Institutes of Brain Science, Department of Neonatology, Children's Hospital of Fudan University, Shanghai, China; Key Laboratory of Neonatal Diseases, National Health Commission, Shanghai, China
| | - Dianyi Li
- State Key Laboratory of Medical Neurobiology, MOE Frontiers Center for Brain Science, and Institutes of Brain Science, Department of Neonatology, Children's Hospital of Fudan University, Shanghai, China
| | - Qingyuan Wei
- State Key Laboratory of Medical Neurobiology, MOE Frontiers Center for Brain Science, and Institutes of Brain Science, Department of Neonatology, Children's Hospital of Fudan University, Shanghai, China
| | - Minghong Shi
- State Key Laboratory of Medical Neurobiology, MOE Frontiers Center for Brain Science, and Institutes of Brain Science, Department of Neonatology, Children's Hospital of Fudan University, Shanghai, China
| | - Jiakun Xiang
- State Key Laboratory of Medical Neurobiology, MOE Frontiers Center for Brain Science, and Institutes of Brain Science, Department of Neonatology, Children's Hospital of Fudan University, Shanghai, China
| | - Ruiwei Gao
- State Key Laboratory of Medical Neurobiology, MOE Frontiers Center for Brain Science, and Institutes of Brain Science, Department of Neonatology, Children's Hospital of Fudan University, Shanghai, China; Key Laboratory of Neonatal Diseases, National Health Commission, Shanghai, China.
| | - Chao Chen
- State Key Laboratory of Medical Neurobiology, MOE Frontiers Center for Brain Science, and Institutes of Brain Science, Department of Neonatology, Children's Hospital of Fudan University, Shanghai, China; Key Laboratory of Neonatal Diseases, National Health Commission, Shanghai, China.
| | - Zhi-Xiang Xu
- State Key Laboratory of Medical Neurobiology, MOE Frontiers Center for Brain Science, and Institutes of Brain Science, Department of Neonatology, Children's Hospital of Fudan University, Shanghai, China; Shanghai Stomatological Hospital & School of Stomatology, Fudan University, Shanghai, China.
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5
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Naseri Kouzehgarani G, Kandel ME, Sakakura M, Dupaty JS, Popescu G, Gillette MU. Circadian Volume Changes in Hippocampal Glia Studied by Label-Free Interferometric Imaging. Cells 2022; 11:2073. [PMID: 35805157 PMCID: PMC9265588 DOI: 10.3390/cells11132073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Revised: 06/02/2022] [Accepted: 06/17/2022] [Indexed: 12/10/2022] Open
Abstract
Complex brain functions, including learning and memory, arise in part from the modulatory role of astrocytes on neuronal circuits. Functionally, the dentate gyrus (DG) exhibits differences in the acquisition of long-term potentiation (LTP) between day and night. We hypothesize that the dynamic nature of astrocyte morphology plays an important role in the functional circuitry of hippocampal learning and memory, specifically in the DG. Standard microscopy techniques, such as differential interference contrast (DIC), present insufficient contrast for detecting changes in astrocyte structure and function and are unable to inform on the intrinsic structure of the sample in a quantitative manner. Recently, gradient light interference microscopy (GLIM) has been developed to upgrade a DIC microscope with quantitative capabilities such as single-cell dry mass and volume characterization. Here, we present a methodology for combining GLIM and electrophysiology to quantify the astrocyte morphological behavior over the day-night cycle. Colocalized measurements of GLIM and fluorescence allowed us to quantify the dry masses and volumes of hundreds of astrocytes. Our results indicate that, on average, there is a 25% cell volume reduction during the nocturnal cycle. Remarkably, this cell volume change takes place at constant dry mass, which suggests that the volume regulation occurs primarily through aqueous medium exchange with the environment.
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Affiliation(s)
- Ghazal Naseri Kouzehgarani
- Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, IL 61820, USA;
- Beckman Institute for Advanced Science & Technology, University of Illinois at Urbana-Champaign, Urbana, IL 61820, USA; (M.E.K.); (M.S.); (G.P.)
| | - Mikhail E. Kandel
- Beckman Institute for Advanced Science & Technology, University of Illinois at Urbana-Champaign, Urbana, IL 61820, USA; (M.E.K.); (M.S.); (G.P.)
- Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61820, USA
| | - Masayoshi Sakakura
- Beckman Institute for Advanced Science & Technology, University of Illinois at Urbana-Champaign, Urbana, IL 61820, USA; (M.E.K.); (M.S.); (G.P.)
- Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61820, USA
| | - Joshua S. Dupaty
- Department of Biomedical Engineering, Mercer University, Macon, GA 31207, USA;
| | - Gabriel Popescu
- Beckman Institute for Advanced Science & Technology, University of Illinois at Urbana-Champaign, Urbana, IL 61820, USA; (M.E.K.); (M.S.); (G.P.)
- Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61820, USA
- Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, IL 61820, USA
| | - Martha U. Gillette
- Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, IL 61820, USA;
- Beckman Institute for Advanced Science & Technology, University of Illinois at Urbana-Champaign, Urbana, IL 61820, USA; (M.E.K.); (M.S.); (G.P.)
- Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, IL 61820, USA
- Department of Cell & Developmental Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61820, USA
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Baudon A, Clauss-Creusot E, Darbon P, Patwell R, Grinevich V, Charlet A. Calcium imaging and BAPTA loading of amygdala astrocytes in mouse brain slices. STAR Protoc 2022; 3:101159. [PMID: 35199029 PMCID: PMC8844720 DOI: 10.1016/j.xpro.2022.101159] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Astrocytes are glial cells that exhibit calcium signaling-mediated activity. Here, we present a protocol to monitor and manipulate astrocyte calcium activity from mouse amygdala slices. In the first part of this protocol, we describe the procedure of astrocyte calcium imaging. In the second part, we detail how to disrupt astrocyte calcium activity by patch-clamp-mediated loading of BAPTA. These two approaches are presented separately but they can also be used simultaneously to monitor the effects of disruption on an astrocyte network. For complete details on the use and execution of this protocol, please refer to Wahis et al. (2021).
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Affiliation(s)
- Angel Baudon
- Centre National de la Recherche Scientifique and University of Strasbourg, Institute of Cellular and Integrative Neuroscience, INCI CNRS UPR3212, 8, Allée du Général Rouvillois, Strasbourg, 67000 France
| | - Etienne Clauss-Creusot
- Centre National de la Recherche Scientifique and University of Strasbourg, Institute of Cellular and Integrative Neuroscience, INCI CNRS UPR3212, 8, Allée du Général Rouvillois, Strasbourg, 67000 France
| | - Pascal Darbon
- Centre National de la Recherche Scientifique and University of Strasbourg, Institute of Cellular and Integrative Neuroscience, INCI CNRS UPR3212, 8, Allée du Général Rouvillois, Strasbourg, 67000 France
| | - Ryan Patwell
- Department of Neuropeptide Research in Psychiatry, Central Institute of Mental Health, University of Heidelberg, Mannheim, 68159 Germany
| | - Valery Grinevich
- Department of Neuropeptide Research in Psychiatry, Central Institute of Mental Health, University of Heidelberg, Mannheim, 68159 Germany
| | - Alexandre Charlet
- Centre National de la Recherche Scientifique and University of Strasbourg, Institute of Cellular and Integrative Neuroscience, INCI CNRS UPR3212, 8, Allée du Général Rouvillois, Strasbourg, 67000 France
- Corresponding author
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7
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Francis AT, Manifold B, Carlson EC, Hu R, Hill AH, Men S, Fu D. In vivo simultaneous nonlinear absorption Raman and fluorescence (SNARF) imaging of mouse brain cortical structures. Commun Biol 2022; 5:222. [PMID: 35273325 PMCID: PMC8913696 DOI: 10.1038/s42003-022-03166-6] [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] [Received: 11/03/2021] [Accepted: 02/08/2022] [Indexed: 12/03/2022] Open
Abstract
Label-free multiphoton microscopy is a powerful platform for biomedical imaging. Recent advancements have demonstrated the capabilities of transient absorption microscopy (TAM) for label-free quantification of hemoglobin and stimulated Raman scattering (SRS) microscopy for pathological assessment of label-free virtual histochemical staining. We propose the combination of TAM and SRS with two-photon excited fluorescence (TPEF) to characterize, quantify, and compare hemodynamics, vessel structure, cell density, and cell identity in vivo between age groups. In this study, we construct a simultaneous nonlinear absorption, Raman, and fluorescence (SNARF) microscope with the highest reported in vivo imaging depth for SRS and TAM at 250–280 μm to enable these multimodal measurements. Using machine learning, we predict capillary-lining cell identities with 90% accuracy based on nuclear morphology and capillary relationship. The microscope and methodology outlined herein provides an exciting route to study several research topics, including neurovascular coupling, blood-brain barrier, and neurodegenerative diseases. In this study a microscope is constructed that carries out simultaneous nonlinear absorption, Raman, and fluorescence (SNARF). Machine learning is then used to predict capillary-lining cell identities with 90% accuracy based on nuclear morphology and capillary relationship, which in combination with the developed microscope, can provide a means to study several fields such as neurovascular coupling.
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Affiliation(s)
- Andrew T Francis
- Department of Chemistry, University of Washington, Seattle, WA, 98195, USA
| | - Bryce Manifold
- Department of Chemistry, University of Washington, Seattle, WA, 98195, USA
| | - Elena C Carlson
- Department of Chemistry, University of Washington, Seattle, WA, 98195, USA
| | - Ruoqian Hu
- Department of Chemistry, University of Washington, Seattle, WA, 98195, USA
| | - Andrew H Hill
- Department of Chemistry, University of Washington, Seattle, WA, 98195, USA
| | - Shuaiqian Men
- Department of Chemistry, University of Washington, Seattle, WA, 98195, USA
| | - Dan Fu
- Department of Chemistry, University of Washington, Seattle, WA, 98195, USA.
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8
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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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Panattoni G, Amoriello R, Memo C, Thalhammer A, Ballerini C, Ballerini L. Diverse inflammatory threats modulate astrocytes Ca 2+ signaling via connexin43 hemichannels in organotypic spinal slices. Mol Brain 2021; 14:159. [PMID: 34696792 PMCID: PMC8547100 DOI: 10.1186/s13041-021-00868-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Accepted: 10/15/2021] [Indexed: 02/07/2023] Open
Abstract
Neuroinflammation is an escalation factor shared by a vast range of central nervous system (CNS) pathologies, from neurodegenerative diseases to neuropsychiatric disorders. CNS immune status emerges by the integration of the responses of resident and not resident cells, leading to alterations in neural circuits functions. To explore spinal cord astrocyte reactivity to inflammatory threats we focused our study on the effects of local inflammation in a controlled micro-environment, the organotypic spinal slices, developed from the spinal cord of mouse embryos. These organ cultures represent a complex in vitro model where sensory-motor cytoarchitecture, synaptic properties and spinal cord resident cells, are retained in a 3D fashion and we recently exploit these cultures to model two diverse immune conditions in the CNS, involving different inflammatory networks and products. Here, we specifically focus on the tuning of calcium signaling in astrocytes by these diverse types of inflammation and we investigate the mechanisms which modulate intracellular calcium release and its spreading among astrocytes in the inflamed environment. Organotypic spinal cord slices are cultured for two or three weeks in vitro (WIV) and exposed for 6 h to a cocktail of cytokines (CKs), composed by tumor necrosis factor alpha (TNF-α), interleukin-1 beta (IL-1 β) and granulocyte macrophage-colony stimulating factor (GM-CSF), or to lipopolysaccharide (LPS). By live calcium imaging of the ventral horn, we document an increase in active astrocytes and in the occurrence of spontaneous calcium oscillations displayed by these cells when exposed to each inflammatory threat. Through several pharmacological treatments, we demonstrate that intracellular calcium sources and the activation of connexin 43 (Cx43) hemichannels have a pivotal role in increasing calcium intercellular communication in both CKs and LPS conditions, while the Cx43 gap junction communication is apparently reduced by the inflammatory treatments.
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Affiliation(s)
- Giulia Panattoni
- International School for Advanced Studies (SISSA/ISAS), 34136, Trieste, Italy
| | - Roberta Amoriello
- International School for Advanced Studies (SISSA/ISAS), 34136, Trieste, Italy.,Dipartimento di Medicina Sperimentale e Clinica, University of Florence, 50139, Florence, Italy
| | - Christian Memo
- International School for Advanced Studies (SISSA/ISAS), 34136, Trieste, Italy
| | - Agnes Thalhammer
- International School for Advanced Studies (SISSA/ISAS), 34136, Trieste, Italy
| | - Clara Ballerini
- Dipartimento di Medicina Sperimentale e Clinica, University of Florence, 50139, Florence, Italy.
| | - Laura Ballerini
- International School for Advanced Studies (SISSA/ISAS), 34136, Trieste, Italy.
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10
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Aryal SP, Neupane KR, Masud AA, Richards CI. Characterization of Astrocyte Morphology and Function Using a Fast and Reliable Tissue Clearing Technique. Curr Protoc 2021; 1:e279. [PMID: 34694747 PMCID: PMC8550103 DOI: 10.1002/cpz1.279] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Astrocytic processes interact with synapses throughout the brain modulating neurotransmitter signaling and synaptic communication. During conditions such as exposure to drugs of abuse and neurological diseases, astrocytes respond by altering their morphological and functional properties. Reactive astrocyte phenotypes exhibit a bushy morphology with altered soma volume and an increased number of processes compared to resting astrocytes. The reactive astrocytic phenotype also overexpresses proteins one of which can be glial fibrillary acidic protein (GFAP). Fluorescence microscopy on thin tissue sections (<20 µm) requires reconstruction, often through multiple sections, to delineate the full astrocytic morphology. In contrast, tissue clearing methods have been developed that enable imaging of larger sections including the whole brain, providing an opportunity to see in-depth changes in single cell structure. In this article, a detailed protocol for studying astrocyte morphology using tissue clearing and subsequent imaging of whole brains as well as region-specific slices is provided. This method is ideal for understanding the effect of different physiological conditions on astrocyte morphology. A standard biochemistry laboratory has the resources to accomplish tissue clearing using this protocol and most universities have the required imaging facilities. Protocols to study brains from both genetically modified mice that contain an astrocyte-specific marker and from wild-type mice using antibody labeling steps after tissue clearing are provided. We also describe general protocols to conduct fluorescence imaging of astrocytes in cleared tissue to characterize their morphology. This protocol could be useful for researchers working in the rapidly growing field of astrocyte biology. © 2021 Wiley Periodicals LLC. Basic Protocol 1: Brain perfusion, fixation, and tissue clearing Alternate Protocol: Clearing brain tissue with passive clarity Basic Protocol 2: Antibody labeling and refractive index matching Basic Protocol 3: Fluorescence imaging and characterization of astrocyte morphology.
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Affiliation(s)
- Surya P Aryal
- Department of Chemistry, University of Kentucky, Lexington, KY, USA
| | - Khaga R Neupane
- Department of Chemistry, University of Kentucky, Lexington, KY, USA
| | - Abdullah A Masud
- Department of Chemistry, University of Kentucky, Lexington, KY, USA
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11
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Potential of Multiscale Astrocyte Imaging for Revealing Mechanisms Underlying Neurodevelopmental Disorders. Int J Mol Sci 2021; 22:ijms221910312. [PMID: 34638653 PMCID: PMC8508625 DOI: 10.3390/ijms221910312] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2021] [Revised: 09/21/2021] [Accepted: 09/22/2021] [Indexed: 01/18/2023] Open
Abstract
Astrocytes provide trophic and metabolic support to neurons and modulate circuit formation during development. In addition, astrocytes help maintain neuronal homeostasis through neurovascular coupling, blood-brain barrier maintenance, clearance of metabolites and nonfunctional proteins via the glymphatic system, extracellular potassium buffering, and regulation of synaptic activity. Thus, astrocyte dysfunction may contribute to a myriad of neurological disorders. Indeed, astrocyte dysfunction during development has been implicated in Rett disease, Alexander's disease, epilepsy, and autism, among other disorders. Numerous disease model mice have been established to investigate these diseases, but important preclinical findings on etiology and pathophysiology have not translated into clinical interventions. A multidisciplinary approach is required to elucidate the mechanism of these diseases because astrocyte dysfunction can result in altered neuronal connectivity, morphology, and activity. Recent progress in neuroimaging techniques has enabled noninvasive investigations of brain structure and function at multiple spatiotemporal scales, and these technologies are expected to facilitate the translation of preclinical findings to clinical studies and ultimately to clinical trials. Here, we review recent progress on astrocyte contributions to neurodevelopmental and neuropsychiatric disorders revealed using novel imaging techniques, from microscopy scale to mesoscopic scale.
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12
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Wang ZG, Wang L, Lamb DC, Chen HJ, Hu Y, Wang HP, Pang DW, Liu SL. Real-Time Dissecting the Dynamics of Drug Transportation in the Live Brain. NANO LETTERS 2021; 21:642-650. [PMID: 33290082 DOI: 10.1021/acs.nanolett.0c04216] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Brain diseases are becoming a more and more serious threat to human health. Many critical properties of the transport mechanisms of drugs in live brains remain poorly understood. In this work, single-particle tracking was used to dissect the transport dynamics of wheat germ agglutinin (WGA) in live brain and characterize the geometry and rheology of the extracellular space (ECS). The results revealed that the movements of WGA were influenced by the specific-binding molecules and the nature of the ECS. We further analyzed the mobility behaviors of WGA globally and quantitatively and found that movement of WGA in brain cells of acute slices was an active transport process associated with actin filaments and microtubules. This work paves the way for studies aiming at characterizing the biophysics of drug transport in the context of live brains, which may contribute to developing potential new therapeutic applications for brain diseases.
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Affiliation(s)
- Zhi-Gang Wang
- State Key Laboratory of Medicinal Chemical Biology, Tianjin Key Laboratory of Biosensing and Molecular Recognition, Research Center for Analytical Sciences, College of Chemistry, and School of Medicine, Nankai University, Tianjin 300071, China
| | - Lei Wang
- State Key Laboratory of Medicinal Chemical Biology, Tianjin Key Laboratory of Biosensing and Molecular Recognition, Research Center for Analytical Sciences, College of Chemistry, and School of Medicine, Nankai University, Tianjin 300071, China
| | - Don C Lamb
- Physical Chemistry, Department of Chemistry, and Center for Integrated Protein Science Munich (CIPSM) and Nanosystems Initiative Munich (NIM), Ludwig-Maximilians-Universität, München 81377, Germany
| | - Hua-Jie Chen
- Engineering Research Center of Nano-Geomaterials of Ministry of Education, Faculty of Materials Science and Chemistry, China University of Geosciences, Wuhan 430074, China
| | - Yusi Hu
- State Key Laboratory of Medicinal Chemical Biology, Tianjin Key Laboratory of Biosensing and Molecular Recognition, Research Center for Analytical Sciences, College of Chemistry, and School of Medicine, Nankai University, Tianjin 300071, China
| | - Hong-Peng Wang
- State Key Laboratory of Medicinal Chemical Biology, Tianjin Key Laboratory of Biosensing and Molecular Recognition, Research Center for Analytical Sciences, College of Chemistry, and School of Medicine, Nankai University, Tianjin 300071, China
| | - Dai-Wen Pang
- State Key Laboratory of Medicinal Chemical Biology, Tianjin Key Laboratory of Biosensing and Molecular Recognition, Research Center for Analytical Sciences, College of Chemistry, and School of Medicine, Nankai University, Tianjin 300071, China
| | - Shu-Lin Liu
- State Key Laboratory of Medicinal Chemical Biology, Tianjin Key Laboratory of Biosensing and Molecular Recognition, Research Center for Analytical Sciences, College of Chemistry, and School of Medicine, Nankai University, Tianjin 300071, China
- Engineering Research Center of Nano-Geomaterials of Ministry of Education, Faculty of Materials Science and Chemistry, China University of Geosciences, Wuhan 430074, China
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13
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Lines J, Martin ED, Kofuji P, Aguilar J, Araque A. Astrocytes modulate sensory-evoked neuronal network activity. Nat Commun 2020; 11:3689. [PMID: 32704144 PMCID: PMC7378834 DOI: 10.1038/s41467-020-17536-3] [Citation(s) in RCA: 82] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2020] [Accepted: 07/01/2020] [Indexed: 11/12/2022] Open
Abstract
While neurons principally mediate brain function, astrocytes are emerging as cells with important neuromodulatory actions in brain physiology. In addition to homeostatic roles, astrocytes respond to neurotransmitters with calcium transients stimulating the release of gliotransmitters that regulate synaptic and neuronal functions. We investigated astrocyte-neuronal network interactions in vivo by combining two-photon microscopy to monitor astrocyte calcium and electrocorticogram to record neuronal network activity in the somatosensory cortex during sensory stimulation. We found astrocytes respond to sensory stimuli in a stimulus-dependent manner. Sensory stimuli elicit a surge of neuronal network activity in the gamma range (30-50 Hz) followed by a delayed astrocyte activity that dampens the steady-state gamma activity. This sensory-evoked gamma activity increase is enhanced in transgenic mice with impaired astrocyte calcium signaling and is decreased by pharmacogenetic stimulation of astrocytes. Therefore, cortical astrocytes respond to sensory inputs and regulate sensory-evoked neuronal network activity maximizing its dynamic range.
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Affiliation(s)
- Justin Lines
- Department of Neuroscience, University of Minnesota, 321 Church St SE, Minneapolis, MN, 55455, USA
| | | | - Paulo Kofuji
- Department of Neuroscience, University of Minnesota, 321 Church St SE, Minneapolis, MN, 55455, USA
| | - Juan Aguilar
- Experimental Neurophysiology, Hospital Nacional de Parapléjicos SESCAM, Finca La Peraleda s/n, 45071, Toledo, Spain.
| | - Alfonso Araque
- Department of Neuroscience, University of Minnesota, 321 Church St SE, Minneapolis, MN, 55455, USA.
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14
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Stress gates an astrocytic energy reservoir to impair synaptic plasticity. Nat Commun 2020; 11:2014. [PMID: 32332733 PMCID: PMC7181611 DOI: 10.1038/s41467-020-15778-9] [Citation(s) in RCA: 79] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Accepted: 03/26/2020] [Indexed: 12/21/2022] Open
Abstract
Astrocytes support the energy demands of synaptic transmission and plasticity. Enduring changes in synaptic efficacy are highly sensitive to stress, yet whether changes to astrocyte bioenergetic control of synapses contributes to stress-impaired plasticity is unclear. Here we show in mice that stress constrains the shuttling of glucose and lactate through astrocyte networks, creating a barrier for neuronal access to an astrocytic energy reservoir in the hippocampus and neocortex, compromising long-term potentiation. Impairing astrocytic delivery of energy substrates by reducing astrocyte gap junction coupling with dominant negative connexin 43 or by disrupting lactate efflux was sufficient to mimic the effects of stress on long-term potentiation. Furthermore, direct restoration of the astrocyte lactate supply alone rescued stress-impaired synaptic plasticity, which was blocked by inhibiting neural lactate uptake. This gating of synaptic plasticity in stress by astrocytic metabolic networks indicates a broader role of astrocyte bioenergetics in determining how experience-dependent information is controlled. Enduring changes in synaptic efficacy are highly sensitive to stress. Here, the authors show that astrocytic delivery of metabolites has an important role in the stress-mediated impairment of synaptic plasticity.
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15
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Sugimoto H, Sato M, Nakai J, Kawakami K. Astrocytes in Atp1a2-deficient heterozygous mice exhibit hyperactivity after induction of cortical spreading depression. FEBS Open Bio 2020; 10:1031-1043. [PMID: 32237043 PMCID: PMC7262908 DOI: 10.1002/2211-5463.12848] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Revised: 03/01/2020] [Accepted: 03/25/2020] [Indexed: 01/17/2023] Open
Abstract
The ATP1A2 coding α2 subunit of Na,K‐ATPase, which is predominantly located in astrocytes, is a causative gene of familial hemiplegic migraine type 2 (FHM2). FHM2 model mice (Atp1a2tmCKwk/+) are susceptible to cortical spreading depression (CSD), which is profoundly related to migraine aura and headache. However, astrocytic properties during CSD have not been examined in FHM2 model mice. Using Atp1a2tmCKwk/+ crossed with transgenic mice expressing G‐CaMP7 in cortical neurons and astrocytes (Atp1a2+/−), we analyzed the changes in Ca2+ concentrations during CSD. The propagation speed of Ca2+ waves and the percentages of astrocytes with elevated Ca2+ concentrations in Atp1a2+/− were higher than those in wild‐type mice. Increased percentages of astrocytes with elevated Ca2+ concentrations in Atp1a2+/− may contribute to FHM2 pathophysiology.
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Affiliation(s)
- Hiroki Sugimoto
- Division of Biology, Center for Molecular Medicine, Jichi Medical University, Tochigi, Japan
| | - Masaaki Sato
- Graduate School of Science and Engineering, Saitama University, Japan.,Brain and Body System Science Institute, Saitama University, Japan.,Laboratory for Mental Biology, RIKEN Center for Brain Science, Saitama, Japan
| | - Junichi Nakai
- Graduate School of Science and Engineering, Saitama University, Japan.,Brain and Body System Science Institute, Saitama University, Japan
| | - Kiyoshi Kawakami
- Division of Biology, Center for Molecular Medicine, Jichi Medical University, Tochigi, Japan
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16
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Batiuk MY, Martirosyan A, Wahis J, de Vin F, Marneffe C, Kusserow C, Koeppen J, Viana JF, Oliveira JF, Voet T, Ponting CP, Belgard TG, Holt MG. Identification of region-specific astrocyte subtypes at single cell resolution. Nat Commun 2020; 11:1220. [PMID: 32139688 PMCID: PMC7058027 DOI: 10.1038/s41467-019-14198-8] [Citation(s) in RCA: 397] [Impact Index Per Article: 99.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Accepted: 12/17/2019] [Indexed: 01/26/2023] Open
Abstract
Astrocytes, a major cell type found throughout the central nervous system, have general roles in the modulation of synapse formation and synaptic transmission, blood-brain barrier formation, and regulation of blood flow, as well as metabolic support of other brain resident cells. Crucially, emerging evidence shows specific adaptations and astrocyte-encoded functions in regions, such as the spinal cord and cerebellum. To investigate the true extent of astrocyte molecular diversity across forebrain regions, we used single-cell RNA sequencing. Our analysis identifies five transcriptomically distinct astrocyte subtypes in adult mouse cortex and hippocampus. Validation of our data in situ reveals distinct spatial positioning of defined subtypes, reflecting the distribution of morphologically and physiologically distinct astrocyte populations. Our findings are evidence for specialized astrocyte subtypes between and within brain regions. The data are available through an online database (https://holt-sc.glialab.org/), providing a resource on which to base explorations of local astrocyte diversity and function in the brain.
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Affiliation(s)
- Mykhailo Y Batiuk
- Laboratory of Glia Biology, VIB-KU Leuven Center for Brain and Disease Research, Leuven, Belgium
- Laboratory of Glia Biology, KU Leuven Department of Neuroscience, Leuven, Belgium
| | - Araks Martirosyan
- Laboratory of Glia Biology, VIB-KU Leuven Center for Brain and Disease Research, Leuven, Belgium
- Laboratory of Glia Biology, KU Leuven Department of Neuroscience, Leuven, Belgium
| | - Jérôme Wahis
- Laboratory of Glia Biology, VIB-KU Leuven Center for Brain and Disease Research, Leuven, Belgium
- Laboratory of Glia Biology, KU Leuven Department of Neuroscience, Leuven, Belgium
| | - Filip de Vin
- Laboratory of Glia Biology, VIB-KU Leuven Center for Brain and Disease Research, Leuven, Belgium
- Laboratory of Glia Biology, KU Leuven Department of Neuroscience, Leuven, Belgium
| | - Catherine Marneffe
- Laboratory of Glia Biology, VIB-KU Leuven Center for Brain and Disease Research, Leuven, Belgium
- Laboratory of Glia Biology, KU Leuven Department of Neuroscience, Leuven, Belgium
| | - Carola Kusserow
- Laboratory of Glia Biology, VIB-KU Leuven Center for Brain and Disease Research, Leuven, Belgium
- Laboratory of Glia Biology, KU Leuven Department of Neuroscience, Leuven, Belgium
| | - Jordan Koeppen
- Laboratory of Glia Biology, VIB-KU Leuven Center for Brain and Disease Research, Leuven, Belgium
- Laboratory of Glia Biology, KU Leuven Department of Neuroscience, Leuven, Belgium
| | - João Filipe Viana
- Life and Health Sciences Research Institute (ICVS), University of Minho, Braga, Portugal
- ICVS/3Bs - PT Government Associate Laboratory, Braga, Portugal
| | - João Filipe Oliveira
- Life and Health Sciences Research Institute (ICVS), University of Minho, Braga, Portugal
- ICVS/3Bs - PT Government Associate Laboratory, Braga, Portugal
- IPCA-EST-2Ai, Polytechnic Institute of Cávado and Ave, Applied Artificial Intelligence Laboratory, IPCA Campus, Barcelos, Portugal
| | - Thierry Voet
- Sanger Institute-EBI Single-Cell Genomics Centre, Wellcome Trust Sanger Institute, Hinxton, UK
- KU Leuven Department of Human Genetics, Leuven, Belgium
| | - Chris P Ponting
- Sanger Institute-EBI Single-Cell Genomics Centre, Wellcome Trust Sanger Institute, Hinxton, UK
- MRC Functional Genomics Unit, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, UK
| | - T Grant Belgard
- MRC Functional Genomics Unit, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
- The Bioinformatics CRO, Niceville, Florida, 32578, USA
| | - Matthew G Holt
- Laboratory of Glia Biology, VIB-KU Leuven Center for Brain and Disease Research, Leuven, Belgium.
- Laboratory of Glia Biology, KU Leuven Department of Neuroscience, Leuven, Belgium.
- Leuven Brain Institute, KU Leuven, Leuven, Belgium.
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17
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Rasmussen R, Matsumoto A, Dahlstrup Sietam M, Yonehara K. A segregated cortical stream for retinal direction selectivity. Nat Commun 2020; 11:831. [PMID: 32047156 PMCID: PMC7012930 DOI: 10.1038/s41467-020-14643-z] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2019] [Accepted: 01/26/2020] [Indexed: 12/31/2022] Open
Abstract
Visual features extracted by retinal circuits are streamed into higher visual areas (HVAs) after being processed along the visual hierarchy. However, how specialized neuronal representations of HVAs are built, based on retinal output channels, remained unclear. Here, we addressed this question by determining the effects of genetically disrupting retinal direction selectivity on motion-evoked responses in visual stages from the retina to HVAs in mice. Direction-selective (DS) cells in the rostrolateral (RL) area that prefer higher temporal frequencies, and that change direction tuning bias as the temporal frequency of a stimulus increases, are selectively reduced upon retinal manipulation. DS cells in the primary visual cortex projecting to area RL, but not to the posteromedial area, were similarly affected. Therefore, the specific connectivity of cortico-cortical projection neurons routes feedforward signaling originating from retinal DS cells preferentially to area RL. We thus identify a cortical processing stream for motion computed in the retina. Visual features are streamed into higher visual areas (HVAs), but how representations in HVAs are built, based on retinal output channels, is unknown. Here, the authors show that specific connectivity of cortical neurons routes retina-originated direction-selective signaling into distinct HVAs.
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Affiliation(s)
- Rune Rasmussen
- Danish Research Institute of Translational Neuroscience-DANDRITE, Nordic-EMBL Partnership for Molecular Medicine, Department of Biomedicine, Aarhus University, 8000, Aarhus C, Denmark
| | - Akihiro Matsumoto
- Danish Research Institute of Translational Neuroscience-DANDRITE, Nordic-EMBL Partnership for Molecular Medicine, Department of Biomedicine, Aarhus University, 8000, Aarhus C, Denmark
| | - Monica Dahlstrup Sietam
- Danish Research Institute of Translational Neuroscience-DANDRITE, Nordic-EMBL Partnership for Molecular Medicine, Department of Biomedicine, Aarhus University, 8000, Aarhus C, Denmark
| | - Keisuke Yonehara
- Danish Research Institute of Translational Neuroscience-DANDRITE, Nordic-EMBL Partnership for Molecular Medicine, Department of Biomedicine, Aarhus University, 8000, Aarhus C, Denmark.
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18
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Adachi C, Kakinuma N, Jo SH, Ishii T, Arai Y, Arai S, Kitaguchi T, Takeda S, Inoue T. Sonic hedgehog enhances calcium oscillations in hippocampal astrocytes. J Biol Chem 2019; 294:16034-16048. [PMID: 31506300 DOI: 10.1074/jbc.ra119.007883] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2019] [Revised: 09/04/2019] [Indexed: 01/05/2023] Open
Abstract
Sonic hedgehog (SHH) is important for organogenesis during development. Recent studies have indicated that SHH is also involved in the proliferation and transformation of astrocytes to the reactive phenotype. However, the mechanisms underlying these are unknown. Involvement of SHH signaling in calcium (Ca) signaling has not been extensively studied. Here, we report that SHH and Smoothened agonist (SAG), an activator of the signaling receptor Smoothened (SMO) in the SHH pathway, activate Ca oscillations in cultured murine hippocampal astrocytes. The response was rapid, on a minute time scale, indicating a noncanonical pathway activity. Pertussis toxin blocked the SAG effect, indicating an involvement of a Gi coupled to SMO. Depletion of extracellular ATP by apyrase, an ATP-degrading enzyme, inhibited the SAG-mediated activation of Ca oscillations. These results indicate that SAG increases extracellular ATP levels by activating ATP release from astrocytes, resulting in Ca oscillation activation. We hypothesize that SHH activates SMO-coupled Gi in astrocytes, causing ATP release and activation of Gq/11-coupled P2 receptors on the same cell or surrounding astrocytes. Transcription factor activities are often modulated by Ca patterns; therefore, SHH signaling may trigger changes in astrocytes by activating Ca oscillations. This enhancement of Ca oscillations by SHH signaling may occur in astrocytes in the brain in vivo because we also observed it in hippocampal brain slices. In summary, SHH and SAG enhance Ca oscillations in hippocampal astrocytes, Gi mediates SAG-induced Ca oscillations downstream of SMO, and ATP-permeable channels may promote the ATP release that activates Ca oscillations in astrocytes.
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Affiliation(s)
- Chihiro Adachi
- Department of Life Science and Medical Bioscience, School of Advanced Science and Engineering, Waseda University, Tokyo 1628480, Japan
| | - Naoto Kakinuma
- Department of Anatomy and Cell Biology, Interdisciplinary School of Medicine & Engineering, University of Yamanashi, Yamanashi 4093898, Japan
| | - Soo Hyun Jo
- Department of Life Science and Medical Bioscience, School of Advanced Science and Engineering, Waseda University, Tokyo 1628480, Japan
| | - Takayuki Ishii
- Department of Life Science and Medical Bioscience, School of Advanced Science and Engineering, Waseda University, Tokyo 1628480, Japan
| | - Yusuke Arai
- Department of Life Science and Medical Bioscience, School of Advanced Science and Engineering, Waseda University, Tokyo 1628480, Japan
| | - Satoshi Arai
- Cell Signaling Group, Waseda Bioscience Research Institute in Singapore (WABIOS), Singapore 138667.,Research Institute for Science and Engineering, Waseda University, Tokyo 1698555, Japan
| | - Tetsuya Kitaguchi
- Cell Signaling Group, Waseda Bioscience Research Institute in Singapore (WABIOS), Singapore 138667.,Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, Tokyo 2268503, Japan
| | - Sen Takeda
- Department of Anatomy and Cell Biology, Interdisciplinary School of Medicine & Engineering, University of Yamanashi, Yamanashi 4093898, Japan
| | - Takafumi Inoue
- Department of Life Science and Medical Bioscience, School of Advanced Science and Engineering, Waseda University, Tokyo 1628480, Japan
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19
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Murmu RP, Fordsmann JC, Cai C, Brazhe A, Thomsen KJ, Lauritzen M. Sensory Stimulation-Induced Astrocytic Calcium Signaling in Electrically Silent Ischemic Penumbra. Front Aging Neurosci 2019; 11:223. [PMID: 31496947 PMCID: PMC6712371 DOI: 10.3389/fnagi.2019.00223] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Accepted: 08/07/2019] [Indexed: 11/14/2022] Open
Abstract
Middle cerebral artery occlusion (MCAO) induces ischemia characterized by a densely ischemic focus, and a less densely ischemic penumbral zone in which neurons and astrocytes display age-dependent dynamic variations in spontaneous Ca2+ activities. However, it is unknown whether penumbral nerve cells respond to sensory stimulation early after stroke onset, which is critical for understanding stimulation-induced stroke therapy. In this study, we investigated the ischemic penumbra’s capacity to respond to somatosensory input. We examined adult (3- to 4-month-old) and old (18- to 24-month-old) male mice at 2–4 h after MCAO, using two-photon microscopy to record somatosensory stimulation-induced neuronal and astrocytic Ca2+ signals in the ischemic penumbra. In both adult and old mice, MCAO abolished spontaneous and stimulation-induced electrical activity in the penumbra, and strongly reduced stimulation-induced Ca2+ responses in neuronal somas (35–82%) and neuropil (92–100%) in the penumbra. In comparison, after stroke, stimulation-induced astrocytic Ca2+ responses in the penumbra were only moderately reduced (by 54–62%) in adult mice, and were even better preserved (reduced by 31–38%) in old mice. Our results suggest that somatosensory stimulation evokes astrocytic Ca2+ activity in the ischemic penumbra. We hypothesize that the relatively preserved excitability of astrocytes, most prominent in aged mice, may modulate protection from ischemic infarcts during early somatosensory activation of an ischemic cortical area. Future neuroprotective efforts in stroke may target spontaneous or stimulation-induced activity of astrocytes in the ischemic penumbra.
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Affiliation(s)
- Reena P Murmu
- Translational Neurobiology Group, Department of Neuroscience, Panum Institute, Center for Healthy Aging, University of Copenhagen, Copenhagen, Denmark
| | - Jonas C Fordsmann
- Translational Neurobiology Group, Department of Neuroscience, Panum Institute, Center for Healthy Aging, University of Copenhagen, Copenhagen, Denmark
| | - Changsi Cai
- Translational Neurobiology Group, Department of Neuroscience, Panum Institute, Center for Healthy Aging, University of Copenhagen, Copenhagen, Denmark
| | - Alexey Brazhe
- Faculty of Biology, Moscow State University, Moscow, Russia
| | - Kirsten J Thomsen
- Translational Neurobiology Group, Department of Neuroscience, Panum Institute, Center for Healthy Aging, University of Copenhagen, Copenhagen, Denmark.,Department of Clinical Neurophysiology, Rigshospitalet, Glostrup, Denmark
| | - Martin Lauritzen
- Translational Neurobiology Group, Department of Neuroscience, Panum Institute, Center for Healthy Aging, University of Copenhagen, Copenhagen, Denmark.,Department of Clinical Neurophysiology, Rigshospitalet, Glostrup, Denmark
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20
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Evans TA, Barkauskas DS, Silver J. Intravital imaging of immune cells and their interactions with other cell types in the spinal cord: Experiments with multicolored moving cells. Exp Neurol 2019; 320:112972. [PMID: 31234058 DOI: 10.1016/j.expneurol.2019.112972] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Revised: 05/25/2019] [Accepted: 06/04/2019] [Indexed: 12/25/2022]
Abstract
Intravital imaging of the immune system is a powerful technique for studying biology of the immune response in the spinal cord using a variety of disease models ranging from traumatic injury to autoimmune disorders. Here, we will discuss specific technical aspects as well as many intriguing biological phenomena that have been revealed with the use of intravital imaging for investigation of the immune system in the spinal cord. We will discuss surgical techniques for exposing and stabilizing the spine that are critical for obtaining images, visualizing immune and CNS cells with genetically expressed fluorescent proteins, fluorescent labeling techniques and briefly discuss some of the challenges of image analysis.
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Affiliation(s)
- Teresa A Evans
- Department of Pediatrics, Stanford University, Stanford, CA, USA.
| | | | - Jerry Silver
- Department of Neurosciences, Case Western Reserve University, Cleveland, OH, USA
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21
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Abstract
Astrocytes are the most abundant cell type in the brain and are a crucial part of solving its mysteries. Originally assumed to be passive supporting cells, astrocyte's functions are now recognized to include active modulation and information processing at the neural synapse. The full extent of the astrocyte contribution to neural processing remains unknown. This is, in part, due to the lack of methods available for astrocyte identification and analysis. Existing strategies employ genetic tools like the astrocyte specific promoters glial fibrillary acidic protein (GFAP) or Aldh1L1 to create transgenic animals with fluorescently labeled astrocytes. Recently, small molecule targeting moieties have enabled the delivery of bright fluorescent dyes to astrocytes. Here, we review methods for targeting astrocytes, with a focus on a recently developed methylpyridinium targeting moiety's development, chemical synthesis, and elaboration to provide new features like light-based spatiotemporal control of cell labeling.
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Affiliation(s)
- Alyssa N Preston
- Department of Chemistry, Stony Brook University, Stony Brook, NY, United States
| | - Danielle A Cervasio
- Department of Pharmacological Sciences, Stony Brook University, Stony Brook, NY, United States
| | - Scott T Laughlin
- Department of Chemistry, Stony Brook University, Stony Brook, NY, United States; Institute of Chemical Biology and Drug Discovery, Stony Brook University, Stony Brook, NY, United States.
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22
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Astrocytic endfeet re-cover blood vessels after removal by laser ablation. Sci Rep 2019; 9:1263. [PMID: 30718555 PMCID: PMC6362239 DOI: 10.1038/s41598-018-37419-4] [Citation(s) in RCA: 66] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Accepted: 12/03/2018] [Indexed: 11/08/2022] Open
Abstract
The astrocyte, one of the glial cells, plays many functional roles. These include provision of nutrients from blood vessels to neurons, supply of neurotransmitters and support of blood-brain barrier (BBB) integrity. Astrocytes are known to support the integrity of BBB through maintenance of the tight junction between endothelial cells of blood vessels. However, evidence of its direct contribution to BBB is lacking owing to technical limitations. In this study, astrocytic endfeet covering blood vessels were removed by the laser ablation method with two photon laser scanning microscopy in in vivo mouse brain, and the re-covering of blood vessels with the astrocytic endfeet was observed in about half of the cases. Blood vessels kept their integrity without astrocytic endfoot covers: leakage of plasma marker dyes, Evans Blue or dextran-conjugated fluorescein, was not observed from stripped blood vessels, while ablation of vascular walls induced extravasation of Evans Blue. These results suggest that the astrocytic endfeet covering blood vessels do not contribute to the immediate BBB barrier.
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23
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Fordsmann JC, Murmu RP, Cai C, Brazhe A, Thomsen KJ, Zambach SA, Lønstrup M, Lind BL, Lauritzen M. Spontaneous astrocytic Ca 2+ activity abounds in electrically suppressed ischemic penumbra of aged mice. Glia 2018; 67:37-52. [PMID: 30427548 DOI: 10.1002/glia.23506] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Revised: 06/12/2018] [Accepted: 07/03/2018] [Indexed: 12/11/2022]
Abstract
Experimental focal cortical ischemic lesions consist of an ischemic core and a potentially salvageable peri-ischemic region, the ischemic penumbra. The activity of neurons and astrocytes is assumed to be suppressed in the penumbra because the electrical function is interrupted, but this is incompletely elucidated. Most experimental stroke studies used young adult animals, whereas stroke is prevalent in the elderly population. Using two-photon imaging in vivo, we here demonstrate extensive but electrically silent, spontaneous Ca2+ activity in neurons and astrocytes in the ischemic penumbra of 18- to 24-month-old mice 2-4 hr after middle cerebral artery occlusion. In comparison, stroke reduced spontaneous Ca2+ activity in neurons and astrocytes in adult mice (3-4 months of age). In aged mice, stroke increased astrocytic spontaneous Ca2+ activity considerably while neuronal spontaneous Ca2+ activity was unchanged. Blockade of action potentials and of purinergic receptors strongly reduced spontaneous Ca2+ activity in both neurons and astrocytes in the penumbra of old stroke mice. This indicates that stroke had a direct influence on mechanisms in presynaptic terminals and on purinergic signaling. Thus, highly dynamic variations in spontaneous Ca2+ activity characterize the electrically compromised penumbra, with remarkable differences between adult and old mice. The data are consistent with the notion that aged neurons and astrocytes take on a different phenotype than young mice. The increased activity of the aged astrocyte phenotype may be harmful to neurons. We suggest that the abundant spontaneous Ca2+ activity in astrocytes in the ischemic penumbra of old mice may be a novel target for neuroprotection strategies. A video abstract of this article can be found at https://youtu.be/AKlwKFsz1qE.
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Affiliation(s)
- Jonas Christoffer Fordsmann
- Department of Neuroscience and Center for Healthy Aging, Panum Institute, University of Copenhagen, Copenhagen, Denmark
| | - Reena Prity Murmu
- Department of Neuroscience and Center for Healthy Aging, Panum Institute, University of Copenhagen, Copenhagen, Denmark
| | - Changsi Cai
- Department of Neuroscience and Center for Healthy Aging, Panum Institute, University of Copenhagen, Copenhagen, Denmark
| | - Alexey Brazhe
- Faculty of Biology, Moscow State University, Moscow, Russia
| | - Kirsten Joan Thomsen
- Department of Neuroscience and Center for Healthy Aging, Panum Institute, University of Copenhagen, Copenhagen, Denmark.,Department of Clinical Neurophysiology, Glostrup Hospital, Glostrup, Denmark
| | - Stefan Andreas Zambach
- Department of Neuroscience and Center for Healthy Aging, Panum Institute, University of Copenhagen, Copenhagen, Denmark
| | - Micael Lønstrup
- Department of Neuroscience and Center for Healthy Aging, Panum Institute, University of Copenhagen, Copenhagen, Denmark
| | - Barbara Lykke Lind
- Department of Neuroscience and Center for Healthy Aging, Panum Institute, University of Copenhagen, Copenhagen, Denmark
| | - Martin Lauritzen
- Department of Neuroscience and Center for Healthy Aging, Panum Institute, University of Copenhagen, Copenhagen, Denmark.,Department of Clinical Neurophysiology, Glostrup Hospital, Glostrup, Denmark
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24
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Abstract
Astrocytes are neural cells of ectodermal, neuroepithelial origin that provide for homeostasis and defense of the central nervous system (CNS). Astrocytes are highly heterogeneous in morphological appearance; they express a multitude of receptors, channels, and membrane transporters. This complement underlies their remarkable adaptive plasticity that defines the functional maintenance of the CNS in development and aging. Astrocytes are tightly integrated into neural networks and act within the context of neural tissue; astrocytes control homeostasis of the CNS at all levels of organization from molecular to the whole organ.
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Affiliation(s)
- Alexei Verkhratsky
- The University of Manchester , Manchester , United Kingdom ; Achúcarro Basque Center for Neuroscience, IKERBASQUE, Basque Foundation for Science , Bilbao , Spain ; Department of Neuroscience, University of the Basque Country UPV/EHU and CIBERNED, Leioa, Spain ; Center for Basic and Translational Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen , Copenhagen , Denmark ; and Center for Translational Neuromedicine, University of Rochester Medical Center , Rochester, New York
| | - Maiken Nedergaard
- The University of Manchester , Manchester , United Kingdom ; Achúcarro Basque Center for Neuroscience, IKERBASQUE, Basque Foundation for Science , Bilbao , Spain ; Department of Neuroscience, University of the Basque Country UPV/EHU and CIBERNED, Leioa, Spain ; Center for Basic and Translational Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen , Copenhagen , Denmark ; and Center for Translational Neuromedicine, University of Rochester Medical Center , Rochester, New York
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25
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Verkhratsky A, Nedergaard M. Physiology of Astroglia. Physiol Rev 2018; 98:239-389. [PMID: 29351512 PMCID: PMC6050349 DOI: 10.1152/physrev.00042.2016] [Citation(s) in RCA: 916] [Impact Index Per Article: 152.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Revised: 03/22/2017] [Accepted: 04/27/2017] [Indexed: 02/07/2023] Open
Abstract
Astrocytes are neural cells of ectodermal, neuroepithelial origin that provide for homeostasis and defense of the central nervous system (CNS). Astrocytes are highly heterogeneous in morphological appearance; they express a multitude of receptors, channels, and membrane transporters. This complement underlies their remarkable adaptive plasticity that defines the functional maintenance of the CNS in development and aging. Astrocytes are tightly integrated into neural networks and act within the context of neural tissue; astrocytes control homeostasis of the CNS at all levels of organization from molecular to the whole organ.
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Affiliation(s)
- Alexei Verkhratsky
- The University of Manchester , Manchester , United Kingdom ; Achúcarro Basque Center for Neuroscience, IKERBASQUE, Basque Foundation for Science , Bilbao , Spain ; Department of Neuroscience, University of the Basque Country UPV/EHU and CIBERNED, Leioa, Spain ; Center for Basic and Translational Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen , Copenhagen , Denmark ; and Center for Translational Neuromedicine, University of Rochester Medical Center , Rochester, New York
| | - Maiken Nedergaard
- The University of Manchester , Manchester , United Kingdom ; Achúcarro Basque Center for Neuroscience, IKERBASQUE, Basque Foundation for Science , Bilbao , Spain ; Department of Neuroscience, University of the Basque Country UPV/EHU and CIBERNED, Leioa, Spain ; Center for Basic and Translational Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen , Copenhagen , Denmark ; and Center for Translational Neuromedicine, University of Rochester Medical Center , Rochester, New York
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26
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Rasmussen R, Jensen MH, Heltberg ML. Chaotic Dynamics Mediate Brain State Transitions, Driven by Changes in Extracellular Ion Concentrations. Cell Syst 2017; 5:591-603.e4. [PMID: 29248375 DOI: 10.1016/j.cels.2017.11.011] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Revised: 09/07/2017] [Accepted: 11/20/2017] [Indexed: 01/05/2023]
Abstract
Previous studies have suggested that changes in extracellular ion concentrations initiate the transition from an activity state that characterizes sleep in cortical neurons to states that characterize wakefulness. However, because neuronal activity and extracellular ion concentrations are interdependent, isolating their unique roles during sleep-wake transitions is not possible in vivo. Here, we extend the Averaged-Neuron model and demonstrate that, although changes in extracellular ion concentrations occur concurrently, decreasing the conductance of calcium-dependent potassium channels initiates the transition from sleep to wakefulness. We find that sleep is governed by stable, self-sustained oscillations in neuronal firing patterns, whereas the quiet awake state and active awake state are both governed by irregular oscillations and chaotic dynamics; transitions between these separable awake states are prompted by ionic changes. Although waking is indicative of a shift from stable to chaotic neuronal firing patterns, we illustrate that the properties of chaotic dynamics ensure that the transition between states is smooth and robust to noise.
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Affiliation(s)
- Rune Rasmussen
- The Danish Research Institute of Translational Neuroscience - DANDRITE, Nordic EMBL Partnership for Molecular Medicine, Department of Biomedicine, Aarhus University, 8000 Aarhus C, Denmark.
| | - Mogens H Jensen
- Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Mathias L Heltberg
- Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark.
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27
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Murphy TR, Davila D, Cuvelier N, Young LR, Lauderdale K, Binder DK, Fiacco TA. Hippocampal and Cortical Pyramidal Neurons Swell in Parallel with Astrocytes during Acute Hypoosmolar Stress. Front Cell Neurosci 2017; 11:275. [PMID: 28979186 PMCID: PMC5611379 DOI: 10.3389/fncel.2017.00275] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Accepted: 08/28/2017] [Indexed: 01/08/2023] Open
Abstract
Normal nervous system function is critically dependent on the balance of water and ions in the extracellular space (ECS). Pathological reduction in brain interstitial osmolarity results in osmotically-driven flux of water into cells, causing cellular edema which reduces the ECS and increases neuronal excitability and risk of seizures. Astrocytes are widely considered to be particularly susceptible to cellular edema due to selective expression of the water channel aquaporin-4 (AQP4). The apparent resistance of pyramidal neurons to osmotic swelling has been attributed to lack of functional water channels. In this study we report rapid volume changes in CA1 pyramidal cells in hypoosmolar ACSF (hACSF) that are equivalent to volume changes in astrocytes across a variety of conditions. Astrocyte and neuronal swelling was significant within 1 min of exposure to 17 or 40% hACSF, was rapidly reversible upon return to normosmolar ACSF, and repeatable upon re-exposure to hACSF. Neuronal swelling was not an artifact of patch clamp, occurred deep in tissue, was similar at physiological vs. room temperature, and occurred in both juvenile and adult hippocampal slices. Neuronal swelling was neither inhibited by TTX, nor by antagonists of NMDA or AMPA receptors, suggesting that it was not occurring as a result of excitotoxicity. Surprisingly, genetic deletion of AQP4 did not inhibit, but rather augmented, astrocyte swelling in severe hypoosmolar conditions. Taken together, our results indicate that neurons are not osmoresistant as previously reported, and that osmotic swelling is driven by an AQP4-independent mechanism.
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Affiliation(s)
- Thomas R. Murphy
- Division of Biomedical Sciences, School of Medicine, University of California, RiversideRiverside, CA, United States
- Center for Glial-Neuronal Interactions, University of California, RiversideRiverside, CA, United States
| | - David Davila
- Center for Glial-Neuronal Interactions, University of California, RiversideRiverside, CA, United States
- Department of Cell Biology and Neuroscience, University of California, RiversideRiverside, CA, United States
| | - Nicholas Cuvelier
- Center for Glial-Neuronal Interactions, University of California, RiversideRiverside, CA, United States
- Department of Cell Biology and Neuroscience, University of California, RiversideRiverside, CA, United States
| | - Leslie R. Young
- Center for Glial-Neuronal Interactions, University of California, RiversideRiverside, CA, United States
- Department of Cell Biology and Neuroscience, University of California, RiversideRiverside, CA, United States
| | - Kelli Lauderdale
- Division of Biomedical Sciences, School of Medicine, University of California, RiversideRiverside, CA, United States
- Center for Glial-Neuronal Interactions, University of California, RiversideRiverside, CA, United States
| | - Devin K. Binder
- Division of Biomedical Sciences, School of Medicine, University of California, RiversideRiverside, CA, United States
- Center for Glial-Neuronal Interactions, University of California, RiversideRiverside, CA, United States
| | - Todd A. Fiacco
- Center for Glial-Neuronal Interactions, University of California, RiversideRiverside, CA, United States
- Department of Cell Biology and Neuroscience, University of California, RiversideRiverside, CA, United States
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28
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Verkhratsky A, Zorec R, Parpura V. Stratification of astrocytes in healthy and diseased brain. Brain Pathol 2017; 27:629-644. [PMID: 28805002 PMCID: PMC5599174 DOI: 10.1111/bpa.12537] [Citation(s) in RCA: 153] [Impact Index Per Article: 21.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Revised: 06/03/2017] [Accepted: 06/06/2017] [Indexed: 12/11/2022] Open
Abstract
Astrocytes, a subtype of glial cells, come in variety of forms and functions. However, overarching role of these cell is in the homeostasis of the brain, be that regulation of ions, neurotransmitters, metabolism or neuronal synaptic networks. Loss of homeostasis represents the underlying cause of all brain disorders. Thus, astrocytes are likely involved in most if not all of the brain pathologies. We tabulate astroglial homeostatic functions along with pathological condition that arise from dysfunction of these glial cells. Classification of astrocytes is presented with the emphasis on evolutionary trails, morphological appearance and numerical preponderance. We note that, even though astrocytes from a variety of mammalian species share some common features, human astrocytes appear to be the largest and most complex of all astrocytes studied thus far. It is then an imperative to develop humanized models to study the role of astrocytes in brain pathologies, which is perhaps most abundantly clear in the case of glioblastoma multiforme.
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Affiliation(s)
- Alexei Verkhratsky
- Division of Neuroscience & Experimental PsychologyThe University of ManchesterManchesterUnited Kingdom
- Achúcarro Basque Center for NeuroscienceIKERBASQUE, Basque Foundation for Science48011 BilbaoSpain
- Department of NeuroscienceUniversity of the Basque Country UPV/EHU and CIBERNED48940 LeioaSpain
| | - Robert Zorec
- Laboratory of Cell EngineeringCelica BIOMEDICAL, Tehnološki park 24, Ljubljana 1000SloveniaEurope
- Laboratory of Neuroendocrinology‐Molecular Cell PhysiologyInstitute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Zaloška 4, Ljubljana 1000SloveniaEurope
| | - Vladimir Parpura
- Department of Neurobiology, Civitan International Research Center and Center for Glial Biology in Medicine, Evelyn F. McKnight Brain Institute, Atomic Force Microscopy & Nanotechnology Laboratories, 1719 6th Avenue South, CIRC 429University of Alabama at BirminghamBirminghamAL 35294‐0021
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29
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Hülsmann S, Hagos L, Heuer H, Schnell C. Limitations of Sulforhodamine 101 for Brain Imaging. Front Cell Neurosci 2017; 11:44. [PMID: 28293173 PMCID: PMC5328990 DOI: 10.3389/fncel.2017.00044] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Accepted: 02/09/2017] [Indexed: 11/19/2022] Open
Abstract
Since 2004, the red fluorescent dye Sulforhodamine 101 (SR101) has been boosting the functional analysis of astrocytes in a functional environment in an unprecedented way. However, two major limitations have been challenging the usefulness of this tool for cellular imaging: (i) SR101 is not as specific for astrocytes as previously reported; and (ii) discoveries of severe excitatory side effects of SR101 are bearing the risk of unwanted alteration of the system of interest. In this article, we summarize the current knowledge about SR101-labeling protocols and discuss the problems that arise from varying of the staining protocols. Furthermore, we provide a testable hypothesis for the observed hyper-excitability that can be observed when using SR101.
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Affiliation(s)
- Swen Hülsmann
- Clinic for Anesthesiology, University Hospital GöttingenGöttingen, Germany; DFG Research Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB)Göttingen, Germany
| | - Liya Hagos
- Clinic for Anesthesiology, University Hospital GöttingenGöttingen, Germany; DFG Research Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB)Göttingen, Germany
| | - Heike Heuer
- Leibniz-Institut für Umweltmedizinische Forschung GmbH Düsseldorf, Germany
| | - Christian Schnell
- DFG Research Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB) Göttingen, Germany
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30
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Kjaerby C, Rasmussen R, Andersen M, Nedergaard M. Does Global Astrocytic Calcium Signaling Participate in Awake Brain State Transitions and Neuronal Circuit Function? Neurochem Res 2017; 42:1810-1822. [PMID: 28210958 DOI: 10.1007/s11064-017-2195-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2016] [Revised: 01/23/2017] [Accepted: 01/24/2017] [Indexed: 12/31/2022]
Abstract
We continuously need to adapt to changing conditions within our surrounding environment, and our brain needs to quickly shift between resting and working activity states in order to allow appropriate behaviors. These global state shifts are intimately linked to the brain-wide release of the neuromodulators, noradrenaline and acetylcholine. Astrocytes have emerged as a new player participating in the regulation of brain activity, and have recently been implicated in brain state shifts. Astrocytes display global Ca2+ signaling in response to activation of the noradrenergic system, but whether astrocytic Ca2+ signaling is causative or correlative for shifts in brain state and neural activity patterns is not known. Here we review the current available literature on astrocytic Ca2+ signaling in awake animals in order to explore the role of astrocytic signaling in brain state shifts. Furthermore, we look at the development and availability of innovative new methodological tools that are opening up for new ways of visualizing and perturbing astrocyte activity in awake behaving animals. With these new tools at hand, the field of astrocyte research will likely be able to elucidate the causal and mechanistic roles of astrocytes in complex behaviors within a very near future.
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Affiliation(s)
- Celia Kjaerby
- Center for Basic and Translational Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Building 24.2, Blegdamsvej 3B, 2200, Copenhagen N, Denmark
| | - Rune Rasmussen
- Center for Basic and Translational Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Building 24.2, Blegdamsvej 3B, 2200, Copenhagen N, Denmark.,Department of Biomedicine, The Danish Research Institute of Translational Neuroscience - DANDRITE, Nordic EMBL Partnership for Molecular Medicine, Aarhus University, 8000, Aarhus C, Denmark
| | - Mie Andersen
- Center for Basic and Translational Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Building 24.2, Blegdamsvej 3B, 2200, Copenhagen N, Denmark
| | - Maiken Nedergaard
- Center for Basic and Translational Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Building 24.2, Blegdamsvej 3B, 2200, Copenhagen N, Denmark. .,Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, NY, 14642, USA.
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31
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Hagos L, Hülsmann S. Unspecific labelling of oligodendrocytes by sulforhodamine 101 depends on astrocytic uptake via the thyroid hormone transporter OATP1C1 (SLCO1C1). Neurosci Lett 2016; 631:13-18. [PMID: 27519929 DOI: 10.1016/j.neulet.2016.08.010] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Revised: 08/08/2016] [Accepted: 08/08/2016] [Indexed: 10/21/2022]
Abstract
The red fluorescent dye Sulforhodamine 101 (SR101) is often used as a marker for astrocytes, although variations of the staining protocol have been shown to influence the preferentially labeled cell type. Here we analyzed SR101-labeling of oligodendrocytes in the hippocampal slices preparation of PLP-EGFP mice. Using different staining protocols, we found robust SR101-labeled oligodendrocytes in the CA1 stratum radiatum of the hippocampus. Application of L-thyroxin, which is known to block SR101 transport into astrocytes via competitive inhibition of the multi-specific OATP1C1 (SLCO1C1) transporter, significantly reduced oligodendrocyte labeling. Since OATP1C1 is not expressed in oligodendrocytes, we conclude that oligodendrocyte labeling with SR101 requires SR101-uptake by astrocytes, which then diffuses to oligodendrocytes via heterotypic gap junctions of the pan-glial network. In summary, unequivocal identification of a particular cell type is not possible by SR101 only, hence caution is recommended when using SR101 in future studies.
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Affiliation(s)
- Liya Hagos
- Clinic for Anesthesiology, University Medical Center, Göttingen, Germany; Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), Germany
| | - Swen Hülsmann
- Clinic for Anesthesiology, University Medical Center, Göttingen, Germany; Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), Germany.
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