1
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Huber RE, Babbitt C, Peyton SR. Heterogeneity of brain extracellular matrix and astrocyte activation. J Neurosci Res 2024; 102:e25356. [PMID: 38773875 DOI: 10.1002/jnr.25356] [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: 08/30/2023] [Revised: 04/01/2024] [Accepted: 05/05/2024] [Indexed: 05/24/2024]
Abstract
From the blood brain barrier to the synaptic space, astrocytes provide structural, metabolic, ionic, and extracellular matrix (ECM) support across the brain. Astrocytes include a vast array of subtypes, their phenotypes and functions varying both regionally and temporally. Astrocytes' metabolic and regulatory functions poise them to be quick and sensitive responders to injury and disease in the brain as revealed by single cell sequencing. Far less is known about the influence of the local healthy and aging microenvironments on these astrocyte activation states. In this forward-looking review, we describe the known relationship between astrocytes and their local microenvironment, the remodeling of the microenvironment during disease and injury, and postulate how they may drive astrocyte activation. We suggest technology development to better understand the dynamic diversity of astrocyte activation states, and how basal and activation states depend on the ECM microenvironment. A deeper understanding of astrocyte response to stimuli in ECM-specific contexts (brain region, age, and sex of individual), paves the way to revolutionize how the field considers astrocyte-ECM interactions in brain injury and disease and opens routes to return astrocytes to a healthy quiescent state.
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Affiliation(s)
- Rebecca E Huber
- Department of Chemical Engineering, University of Massachusetts Amherst, Amherst, Massachusetts, USA
| | - Courtney Babbitt
- Department of Biology, University of Massachusetts Amherst, Amherst, Massachusetts, USA
| | - Shelly R Peyton
- Department of Chemical Engineering, University of Massachusetts Amherst, Amherst, Massachusetts, USA
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2
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Cahill MK, Collard M, Tse V, Reitman ME, Etchenique R, Kirst C, Poskanzer KE. Network-level encoding of local neurotransmitters in cortical astrocytes. Nature 2024; 629:146-153. [PMID: 38632406 PMCID: PMC11062919 DOI: 10.1038/s41586-024-07311-5] [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: 04/03/2023] [Accepted: 03/13/2024] [Indexed: 04/19/2024]
Abstract
Astrocytes, the most abundant non-neuronal cell type in the mammalian brain, are crucial circuit components that respond to and modulate neuronal activity through calcium (Ca2+) signalling1-7. Astrocyte Ca2+ activity is highly heterogeneous and occurs across multiple spatiotemporal scales-from fast, subcellular activity3,4 to slow, synchronized activity across connected astrocyte networks8-10-to influence many processes5,7,11. However, the inputs that drive astrocyte network dynamics remain unclear. Here we used ex vivo and in vivo two-photon astrocyte imaging while mimicking neuronal neurotransmitter inputs at multiple spatiotemporal scales. We find that brief, subcellular inputs of GABA and glutamate lead to widespread, long-lasting astrocyte Ca2+ responses beyond an individual stimulated cell. Further, we find that a key subset of Ca2+ activity-propagative activity-differentiates astrocyte network responses to these two main neurotransmitters, and may influence responses to future inputs. Together, our results demonstrate that local, transient neurotransmitter inputs are encoded by broad cortical astrocyte networks over a minutes-long time course, contributing to accumulating evidence that substantial astrocyte-neuron communication occurs across slow, network-level spatiotemporal scales12-14. These findings will enable future studies to investigate the link between specific astrocyte Ca2+ activity and specific functional outputs, which could build a consistent framework for astrocytic modulation of neuronal activity.
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Affiliation(s)
- Michelle K Cahill
- Department of Biochemistry & Biophysics, University of California, San Francisco, CA, USA
- Neuroscience Graduate Program, University of California, San Francisco, CA, USA
| | - Max Collard
- Department of Biochemistry & Biophysics, University of California, San Francisco, CA, USA
- Neuroscience Graduate Program, University of California, San Francisco, CA, USA
| | - Vincent Tse
- Department of Biochemistry & Biophysics, University of California, San Francisco, CA, USA
| | - Michael E Reitman
- Department of Biochemistry & Biophysics, University of California, San Francisco, CA, USA
- Neuroscience Graduate Program, University of California, San Francisco, CA, USA
| | - Roberto Etchenique
- Departamento de Química Inorgánica, Analítica y Química Física, INQUIMAE, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, CONICET, Buenos Aires, Argentina
| | - Christoph Kirst
- Neuroscience Graduate Program, University of California, San Francisco, CA, USA
- Department of Anatomy, University of California, San Francisco, CA, USA
- Kavli Institute for Fundamental Neuroscience, San Francisco, CA, USA
- Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Kira E Poskanzer
- Department of Biochemistry & Biophysics, University of California, San Francisco, CA, USA.
- Neuroscience Graduate Program, University of California, San Francisco, CA, USA.
- Kavli Institute for Fundamental Neuroscience, San Francisco, CA, USA.
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3
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Rupprecht P, Duss SN, Becker D, Lewis CM, Bohacek J, Helmchen F. Centripetal integration of past events in hippocampal astrocytes regulated by locus coeruleus. Nat Neurosci 2024; 27:927-939. [PMID: 38570661 PMCID: PMC11089000 DOI: 10.1038/s41593-024-01612-8] [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: 07/26/2022] [Accepted: 02/26/2024] [Indexed: 04/05/2024]
Abstract
An essential feature of neurons is their ability to centrally integrate information from their dendrites. The activity of astrocytes, in contrast, has been described as mostly uncoordinated across cellular compartments without clear central integration. Here we report conditional integration of calcium signals in astrocytic distal processes at their soma. In the hippocampus of adult mice of both sexes, we found that global astrocytic activity, as recorded with population calcium imaging, reflected past neuronal and behavioral events on a timescale of seconds. Salient past events, indicated by pupil dilations, facilitated the propagation of calcium signals from distal processes to the soma. Centripetal propagation to the soma was reproduced by optogenetic activation of the locus coeruleus, a key regulator of arousal, and reduced by pharmacological inhibition of α1-adrenergic receptors. Together, our results suggest that astrocytes are computational units of the brain that slowly and conditionally integrate calcium signals upon behaviorally relevant events.
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Affiliation(s)
- Peter Rupprecht
- Laboratory of Neural Circuit Dynamics, Brain Research Institute, University of Zurich, Zürich, Switzerland.
- Neuroscience Center Zurich, University of Zurich and ETH Zurich, Zürich, Switzerland.
| | - Sian N Duss
- Neuroscience Center Zurich, University of Zurich and ETH Zurich, Zürich, Switzerland
- Laboratory of Molecular and Behavioral Neuroscience, Institute for Neuroscience, Department of Health Sciences and Technology, ETH Zurich, Zürich, Switzerland
| | - Denise Becker
- Laboratory of Neural Circuit Dynamics, Brain Research Institute, University of Zurich, Zürich, Switzerland
| | - Christopher M Lewis
- Laboratory of Neural Circuit Dynamics, Brain Research Institute, University of Zurich, Zürich, Switzerland
| | - Johannes Bohacek
- Neuroscience Center Zurich, University of Zurich and ETH Zurich, Zürich, Switzerland
- Laboratory of Molecular and Behavioral Neuroscience, Institute for Neuroscience, Department of Health Sciences and Technology, ETH Zurich, Zürich, Switzerland
| | - Fritjof Helmchen
- Laboratory of Neural Circuit Dynamics, Brain Research Institute, University of Zurich, Zürich, Switzerland.
- Neuroscience Center Zurich, University of Zurich and ETH Zurich, Zürich, Switzerland.
- University Research Priority Program (URPP), Adaptive Brain Circuits in Development and Learning, University of Zurich, Zürich, Switzerland.
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4
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Evans WR, Baskar SS, Costa ARCE, Ravoori S, Arigbe A, Huda R. Functional activation of dorsal striatum astrocytes improves movement deficits in hemi-parkinsonian mice. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.02.587694. [PMID: 38617230 PMCID: PMC11014576 DOI: 10.1101/2024.04.02.587694] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/16/2024]
Abstract
Parkinson's disease (PD) is characterized by the degeneration of dopaminergic nigrostriatal inputs, which causes striatal network dysfunction and leads to pronounced motor deficits. Recent evidence highlights astrocytes as a potential local source of striatal network modulation. However, it remains unknown how dopamine loss affects striatal astrocyte activity and whether astrocyte activity regulates behavioral deficits in PD. We addressed these questions by performing astrocyte-specific calcium recordings and manipulations using in vivo fiber photometry and chemogenetics. We find that locomotion elicits astrocyte calcium activity over a slower timescale than neurons. Unilateral dopamine depletion reduced locomotion-related astrocyte responses. Chemogenetic activation facilitated astrocyte activity, and improved asymmetrical motor deficits and open field exploratory behavior in dopamine lesioned mice. Together, our results establish a novel role for functional striatal astrocyte signaling in modulating motor function in PD and highlight non-neuronal targets for potential PD therapeutics.
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Affiliation(s)
- Wesley R. Evans
- WM Keck Center for Collaborative Neuroscience, Rutgers University, Piscataway NJ, 08854, USA
| | - Sindhuja S. Baskar
- WM Keck Center for Collaborative Neuroscience, Rutgers University, Piscataway NJ, 08854, USA
| | | | - Sanya Ravoori
- WM Keck Center for Collaborative Neuroscience, Rutgers University, Piscataway NJ, 08854, USA
| | - Abimbola Arigbe
- WM Keck Center for Collaborative Neuroscience, Rutgers University, Piscataway NJ, 08854, USA
| | - Rafiq Huda
- WM Keck Center for Collaborative Neuroscience, Rutgers University, Piscataway NJ, 08854, USA
- Department of Cell Biology and Neuroscience, Rutgers University, Piscataway NJ, 08854, USA
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5
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Renden RB, Institoris A, Sharma K, Tran CHT. Modulatory effects of noradrenergic and serotonergic signaling pathway on neurovascular coupling. Commun Biol 2024; 7:287. [PMID: 38459113 PMCID: PMC10923894 DOI: 10.1038/s42003-024-05996-y] [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: 06/24/2023] [Accepted: 02/28/2024] [Indexed: 03/10/2024] Open
Abstract
Dynamic changes in astrocyte Ca2+ are recognized as contributors to functional hyperemia, a critical response to increased neuronal activity mediated by a process known as neurovascular coupling (NVC). Although the critical role of glutamatergic signaling in this process has been extensively investigated, the impact of behavioral state, and the release of behavior-associated neurotransmitters, such as norepinephrine and serotonin, on astrocyte Ca2+ dynamics and functional hyperemia have received less attention. We used two-photon imaging of the barrel cortex in awake mice to examine the role of noradrenergic and serotonergic projections in NVC. We found that both neurotransmitters facilitated sensory stimulation-induced increases in astrocyte Ca2+. Interestingly, while ablation of serotonergic neurons reduced sensory stimulation-induced functional hyperemia, ablation of noradrenergic neurons caused both attenuation and potentiation of functional hyperemia. Our study demonstrates that norepinephrine and serotonin are involved in modulating sensory stimulation-induced astrocyte Ca2+ elevations and identifies their differential effects in regulating functional hyperemia.
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Affiliation(s)
- Robert B Renden
- Department of Physiology and Cell Biology, School of Medicine, University of Nevada Reno, Reno, NV, USA
| | - Adam Institoris
- Hotchkiss Brain Institute, Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - Kushal Sharma
- Department of Physiology and Cell Biology, School of Medicine, University of Nevada Reno, Reno, NV, USA
| | - Cam Ha T Tran
- Department of Physiology and Cell Biology, School of Medicine, University of Nevada Reno, Reno, NV, USA.
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6
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Uribe-Arias A, Rozenblat R, Vinepinsky E, Marachlian E, Kulkarni A, Zada D, Privat M, Topsakalian D, Charpy S, Candat V, Nourin S, Appelbaum L, Sumbre G. Radial astrocyte synchronization modulates the visual system during behavioral-state transitions. Neuron 2023; 111:4040-4057.e6. [PMID: 37863038 PMCID: PMC10783638 DOI: 10.1016/j.neuron.2023.09.022] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Revised: 08/01/2023] [Accepted: 09/15/2023] [Indexed: 10/22/2023]
Abstract
Glial cells support the function of neurons. Recent evidence shows that astrocytes are also involved in brain computations. To explore whether and how their excitable nature affects brain computations and motor behaviors, we used two-photon Ca2+ imaging of zebrafish larvae expressing GCaMP in both neurons and radial astrocytes (RAs). We found that in the optic tectum, RAs synchronize their Ca2+ transients immediately after the end of an escape behavior. Using optogenetics, ablations, and a genetically encoded norepinephrine sensor, we observed that RA synchronous Ca2+ events are mediated by the locus coeruleus (LC)-norepinephrine circuit. RA synchronization did not induce direct excitation or inhibition of tectal neurons. Nevertheless, it modulated the direction selectivity and the long-distance functional correlations among neurons. This mechanism supports freezing behavior following a switch to an alerted state. These results show that LC-mediated neuro-glial interactions modulate the visual system during transitions between behavioral states.
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Affiliation(s)
- Alejandro Uribe-Arias
- Institut de Biologie de l'ENS (IBENS), Département de biologie, École normale supérieure, CNRS, INSERM, Université PSL, 75005 Paris, France
| | - Rotem Rozenblat
- The Faculty of Life Sciences and The Multidisciplinary Brain Research Center, Bar-Ilan University, Ramat-Gan, Israel
| | - Ehud Vinepinsky
- Institut de Biologie de l'ENS (IBENS), Département de biologie, École normale supérieure, CNRS, INSERM, Université PSL, 75005 Paris, France
| | - Emiliano Marachlian
- Institut de Biologie de l'ENS (IBENS), Département de biologie, École normale supérieure, CNRS, INSERM, Université PSL, 75005 Paris, France
| | - Anirudh Kulkarni
- Institut de Biologie de l'ENS (IBENS), Département de biologie, École normale supérieure, CNRS, INSERM, Université PSL, 75005 Paris, France
| | - David Zada
- The Faculty of Life Sciences and The Multidisciplinary Brain Research Center, Bar-Ilan University, Ramat-Gan, Israel
| | - Martin Privat
- Institut de Biologie de l'ENS (IBENS), Département de biologie, École normale supérieure, CNRS, INSERM, Université PSL, 75005 Paris, France
| | - Diego Topsakalian
- Institut de Biologie de l'ENS (IBENS), Département de biologie, École normale supérieure, CNRS, INSERM, Université PSL, 75005 Paris, France
| | - Sarah Charpy
- Institut de Biologie de l'ENS (IBENS), Département de biologie, École normale supérieure, CNRS, INSERM, Université PSL, 75005 Paris, France
| | - Virginie Candat
- Institut de Biologie de l'ENS (IBENS), Département de biologie, École normale supérieure, CNRS, INSERM, Université PSL, 75005 Paris, France
| | - Sarah Nourin
- Institut de Biologie de l'ENS (IBENS), Département de biologie, École normale supérieure, CNRS, INSERM, Université PSL, 75005 Paris, France
| | - Lior Appelbaum
- The Faculty of Life Sciences and The Multidisciplinary Brain Research Center, Bar-Ilan University, Ramat-Gan, Israel
| | - Germán Sumbre
- Institut de Biologie de l'ENS (IBENS), Département de biologie, École normale supérieure, CNRS, INSERM, Université PSL, 75005 Paris, France.
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7
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Cahill MK, Collard M, Tse V, Reitman ME, Etchenique R, Kirst C, Poskanzer KE. Network-level encoding of local neurotransmitters in cortical astrocytes. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.01.568932. [PMID: 38106119 PMCID: PMC10723263 DOI: 10.1101/2023.12.01.568932] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2023]
Abstract
Astrocytes-the most abundant non-neuronal cell type in the mammalian brain-are crucial circuit components that respond to and modulate neuronal activity via calcium (Ca 2+ ) signaling 1-8 . Astrocyte Ca 2+ activity is highly heterogeneous and occurs across multiple spatiotemporal scales: from fast, subcellular activity 3,4 to slow, synchronized activity that travels across connected astrocyte networks 9-11 . Furthermore, astrocyte network activity has been shown to influence a wide range of processes 5,8,12 . While astrocyte network activity has important implications for neuronal circuit function, the inputs that drive astrocyte network dynamics remain unclear. Here we used ex vivo and in vivo two-photon Ca 2+ imaging of astrocytes while mimicking neuronal neurotransmitter inputs at multiple spatiotemporal scales. We find that brief, subcellular inputs of GABA and glutamate lead to widespread, long-lasting astrocyte Ca 2+ responses beyond an individual stimulated cell. Further, we find that a key subset of Ca 2+ activity-propagative events-differentiates astrocyte network responses to these two major neurotransmitters, and gates responses to future inputs. Together, our results demonstrate that local, transient neurotransmitter inputs are encoded by broad cortical astrocyte networks over the course of minutes, contributing to accumulating evidence across multiple model organisms that significant astrocyte-neuron communication occurs across slow, network-level spatiotemporal scales 13-15 . We anticipate that this study will be a starting point for future studies investigating the link between specific astrocyte Ca 2+ activity and specific astrocyte functional outputs, which could build a consistent framework for astrocytic modulation of neuronal activity.
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8
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Hull VL, Wang Y, Burns T, Sternbach S, Gong S, McDonough J, Guo F, Borodinsky LN, Pleasure D. Pathological Bergmann glia alterations and disrupted calcium dynamics in ataxic Canavan disease mice. Glia 2023; 71:2832-2849. [PMID: 37610133 PMCID: PMC10591969 DOI: 10.1002/glia.24454] [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: 12/20/2022] [Revised: 07/11/2023] [Accepted: 07/28/2023] [Indexed: 08/24/2023]
Abstract
Canavan disease (CD) is a recessively inherited pediatric leukodystrophy resulting from inactivating mutations to the oligodendroglial enzyme aspartoacylase (ASPA). ASPA is responsible for hydrolyzing the amino acid derivative N-acetyl-L-aspartate (NAA), and without it, brain NAA concentrations increase by 50% or more. Infants and children with CD present with progressive cognitive and motor delays, cytotoxic edema, astroglial vacuolation, and prominent spongiform brain degeneration. ASPA-deficient CD mice (Aspanur7/nur7 ) present similarly with elevated NAA, widespread astroglial dysfunction, ataxia, and Purkinje cell (PC) dendritic atrophy. Bergmann glia (BG), radial astrocytes essential for cerebellar development, are intimately intertwined with PCs, where they regulate synapse stability, functionality, and plasticity. BG damage is common to many neurodegenerative conditions and frequently associated with PC dysfunction and ataxia. Here, we report that, in CD mice, BG exhibit significant morphological alterations, decreased structural associations with PCs, loss of synaptic support proteins, and altered calcium dynamics. We also find that BG dysfunction predates cerebellar vacuolation and PC damage in CD mice. Previously, we developed an antisense oligonucleotide (ASO) therapy targeting Nat8l (N-acetyltransferase-8-like, "Nat8l ASO") that inhibits the production of NAA and reverses ataxia and PC atrophy in CD mice. Here, we show that Nat8l ASO administration in adult CD mice also leads to BG repair. Furthermore, blocking astroglial uptake of NAA is neuroprotective in astroglia-neuron cocultures exposed to elevated NAA. Our findings suggest that restoration of BG structural and functional integrity could be a mechanism for PC regeneration and improved motor function.
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Affiliation(s)
- Vanessa L. Hull
- Department of Neurology, University of California Davis School of Medicine, Sacramento, California, USA
- Institute for Pediatric Regenerative Medicine, Shriners Hospital for Children, Sacramento, California, USA
| | - Yan Wang
- Department of Neurology, University of California Davis School of Medicine, Sacramento, California, USA
- Institute for Pediatric Regenerative Medicine, Shriners Hospital for Children, Sacramento, California, USA
| | - Travis Burns
- Department of Neurology, University of California Davis School of Medicine, Sacramento, California, USA
- Institute for Pediatric Regenerative Medicine, Shriners Hospital for Children, Sacramento, California, USA
| | - Sarah Sternbach
- Department of Biological Sciences, Kent State University, Kent, Ohio, USA
| | - Shuaishuai Gong
- Department of Neurology, University of California Davis School of Medicine, Sacramento, California, USA
- Institute for Pediatric Regenerative Medicine, Shriners Hospital for Children, Sacramento, California, USA
| | - Jennifer McDonough
- Department of Biological Sciences, Kent State University, Kent, Ohio, USA
| | - Fuzheng Guo
- Department of Neurology, University of California Davis School of Medicine, Sacramento, California, USA
- Institute for Pediatric Regenerative Medicine, Shriners Hospital for Children, Sacramento, California, USA
| | - Laura N. Borodinsky
- Institute for Pediatric Regenerative Medicine, Shriners Hospital for Children, Sacramento, California, USA
- Department of Physiology & Membrane Biology, University of California Davis School of Medicine, Sacramento, California, USA
| | - David Pleasure
- Department of Neurology, University of California Davis School of Medicine, Sacramento, California, USA
- Institute for Pediatric Regenerative Medicine, Shriners Hospital for Children, Sacramento, California, USA
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9
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Stopper G, Caudal LC, Rieder P, Gobbo D, Stopper L, Felix L, Everaerts K, Bai X, Rose CR, Scheller A, Kirchhoff F. Novel algorithms for improved detection and analysis of fluorescent signal fluctuations. Pflugers Arch 2023; 475:1283-1300. [PMID: 37700120 PMCID: PMC10567899 DOI: 10.1007/s00424-023-02855-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Revised: 08/02/2023] [Accepted: 08/26/2023] [Indexed: 09/14/2023]
Abstract
Fluorescent dyes and genetically encoded fluorescence indicators (GEFI) are common tools for visualizing concentration changes of specific ions and messenger molecules during intra- as well as intercellular communication. Using advanced imaging technologies, fluorescence indicators are a prerequisite for the analysis of physiological molecular signaling. Automated detection and analysis of fluorescence signals require to overcome several challenges, including correct estimation of fluorescence fluctuations at basal concentrations of messenger molecules, detection, and extraction of events themselves as well as proper segmentation of neighboring events. Moreover, event detection algorithms need to be sensitive enough to accurately capture localized and low amplitude events exhibiting a limited spatial extent. Here, we present two algorithms (PBasE and CoRoDe) for accurate baseline estimation and automated detection and segmentation of fluorescence fluctuations.
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Affiliation(s)
- Gebhard Stopper
- Department of Molecular Physiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), University of Saarland, Building 48, 66421, Homburg, Germany
| | - Laura C Caudal
- Department of Molecular Physiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), University of Saarland, Building 48, 66421, Homburg, Germany
| | - Phillip Rieder
- Department of Molecular Physiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), University of Saarland, Building 48, 66421, Homburg, Germany
| | - Davide Gobbo
- Department of Molecular Physiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), University of Saarland, Building 48, 66421, Homburg, Germany
| | - Laura Stopper
- Department of Molecular Physiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), University of Saarland, Building 48, 66421, Homburg, Germany
| | - Lisa Felix
- Institute of Neurobiology, Faculty of Mathematics and Natural Sciences, Heinrich Heine University Düsseldorf, 40225, Düsseldorf, Germany
| | - Katharina Everaerts
- Institute of Neurobiology, Faculty of Mathematics and Natural Sciences, Heinrich Heine University Düsseldorf, 40225, Düsseldorf, Germany
| | - Xianshu Bai
- Department of Molecular Physiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), University of Saarland, Building 48, 66421, Homburg, Germany
| | - Christine R Rose
- Institute of Neurobiology, Faculty of Mathematics and Natural Sciences, Heinrich Heine University Düsseldorf, 40225, Düsseldorf, Germany
| | - Anja Scheller
- Department of Molecular Physiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), University of Saarland, Building 48, 66421, Homburg, Germany
| | - Frank Kirchhoff
- Department of Molecular Physiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), University of Saarland, Building 48, 66421, Homburg, Germany.
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10
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Brazhe A, Verisokin A, Verveyko D, Postnov D. Astrocytes: new evidence, new models, new roles. Biophys Rev 2023; 15:1303-1333. [PMID: 37975000 PMCID: PMC10643736 DOI: 10.1007/s12551-023-01145-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Accepted: 09/08/2023] [Indexed: 11/19/2023] Open
Abstract
Astrocytes have been in the limelight of active research for about 3 decades now. Over this period, ideas about their function and role in the nervous system have evolved from simple assistance in energy supply and homeostasis maintenance to a complex informational and metabolic hub that integrates data on local neuronal activity, sensory and arousal context, and orchestrates many crucial processes in the brain. Rapid progress in experimental techniques and data analysis produces a growing body of data, which can be used as a foundation for formulation of new hypotheses, building new refined mathematical models, and ultimately should lead to a new level of understanding of the contribution of astrocytes to the cognitive tasks performed by the brain. Here, we highlight recent progress in astrocyte research, which we believe expands our understanding of how low-level signaling at a cellular level builds up to processes at the level of the whole brain and animal behavior. We start our review with revisiting data on the role of noradrenaline-mediated astrocytic signaling in locomotion, arousal, sensory integration, memory, and sleep. We then briefly review astrocyte contribution to the regulation of cerebral blood flow regulation, which is followed by a discussion of biophysical mechanisms underlying astrocyte effects on different brain processes. The experimental section is closed by an overview of recent experimental techniques available for modulation and visualization of astrocyte dynamics. We then evaluate how the new data can be potentially incorporated into the new mathematical models or where and how it already has been done. Finally, we discuss an interesting prospect that astrocytes may be key players in important processes such as the switching between sleep and wakefulness and the removal of toxic metabolites from the brain milieu.
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Affiliation(s)
- Alexey Brazhe
- Department of Biophysics, Biological Faculty, Lomonosov Moscow State University, Leninskie Gory, 1/24, Moscow, 119234 Russia
- Department of Molecular Neurobiology, Institute of Bioorganic Chemistry RAS, GSP-7, Miklukho-Maklay Str., 16/10, Moscow, 117997 Russia
| | - Andrey Verisokin
- Department of Theoretical Physics, Kursk State University, Radishcheva st., 33, Kursk, 305000 Russia
| | - Darya Verveyko
- Department of Theoretical Physics, Kursk State University, Radishcheva st., 33, Kursk, 305000 Russia
| | - Dmitry Postnov
- Department of Optics and Biophotonics, Saratov State University, Astrakhanskaya st., 83, Saratov, 410012 Russia
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11
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Salinas-Birt A, Zhu X, Lim EY, Cruz Santory AJ, Ye L, Paukert M. Constraints of vigilance-dependent noradrenergic signaling to mouse cerebellar Bergmann glia. Glia 2023; 71:1451-1465. [PMID: 36790089 PMCID: PMC10082684 DOI: 10.1002/glia.24350] [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: 08/01/2022] [Revised: 01/25/2023] [Accepted: 01/25/2023] [Indexed: 02/16/2023]
Abstract
Behavioral state plays an important role in determining astroglia Ca2+ signaling. In particular, locomotion-mediated elevated vigilance has been found to trigger norepinephrine-dependent whole cell Ca2+ elevations in astroglia throughout the brain. For cerebellar Bergmann glia it has recently been found that locomotion-induced transient Ca2+ elevations depend on their α1A -adrenergic receptors. With increasing availability and implementation of locomotion as behavioral parameter it becomes important to understand the constraints of noradrenergic signaling to astroglia. Here we evaluated the effect of speed, duration and interval of locomotion on Ca2+ signals in Bergmann glia as well as cerebellar noradrenergic axon terminals. We found almost no dependence on locomotion speed, but following the initial Ca2+ transient prolonged locomotion events revealed a steady-state Ca2+ elevation. Comparison of time course and recovery of transient Bergmann glia and noradrenergic terminal Ca2+ dynamics suggested that noradrenergic terminal Ca2+ activity determines Bergmann glia Ca2+ activation and does not require noradrenergic receptor desensitization to account for attenuation during prolonged locomotion. Further, analyzing the correlation among Ca2+ dynamics within regions within the field of observation we found that coordinated activity among noradrenergic terminals accounts for fluctuations of steady-state Bergmann glia Ca2+ activity. Together, our findings will help to better understand astroglia Ca2+ dynamics during less controlled awake behavior and may guide the identification of behavioral contexts preferably dependent on astroglia Ca2+ signaling.
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Affiliation(s)
- Angelica Salinas-Birt
- Department of Cellular and Integrative Physiology, University of Texas Health Science Center at San Antonio, San Antonio, Texas, USA
- Center for Biomedical Neuroscience, University of Texas Health Science Center at San Antonio, San Antonio, Texas, USA
| | - Xiangyu Zhu
- Department of Cellular and Integrative Physiology, University of Texas Health Science Center at San Antonio, San Antonio, Texas, USA
- Xiangya School of Medicine, Central South University, Changsha, China
| | - Eunice Y. Lim
- Department of Cellular and Integrative Physiology, University of Texas Health Science Center at San Antonio, San Antonio, Texas, USA
- Center for Biomedical Neuroscience, University of Texas Health Science Center at San Antonio, San Antonio, Texas, USA
| | - Aryana J. Cruz Santory
- Department of Cellular and Integrative Physiology, University of Texas Health Science Center at San Antonio, San Antonio, Texas, USA
| | - Liang Ye
- Department of Cellular and Integrative Physiology, University of Texas Health Science Center at San Antonio, San Antonio, Texas, USA
| | - Martin Paukert
- Department of Cellular and Integrative Physiology, University of Texas Health Science Center at San Antonio, San Antonio, Texas, USA
- Center for Biomedical Neuroscience, University of Texas Health Science Center at San Antonio, San Antonio, Texas, USA
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12
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Rasmussen RN, Asiminas A, Carlsen EMM, Kjaerby C, Smith NA. Astrocytes: integrators of arousal state and sensory context. Trends Neurosci 2023; 46:418-425. [PMID: 37003933 PMCID: PMC10192111 DOI: 10.1016/j.tins.2023.03.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Revised: 02/24/2023] [Accepted: 03/05/2023] [Indexed: 04/01/2023]
Abstract
The integration of external information with the internal state of the body is central to the survival of virtually every multicellular organism. However, a complete picture of the mechanisms that govern this process is lacking. In this opinion article, we synthesize evidence demonstrating that astrocytes sense the momentary arousal state - through neuromodulator release - as well as the sensory inputs - through local synaptic activity - and respond to them with changes in calcium (Ca2+) signaling. We hypothesize that astrocytes integrate sensory signals with the internal state and that this process is necessary to secure optimal behavior. Finally, we argue that dysfunctional astrocytic Ca2+ signaling could be an underlying factor in disorders characterized by disrupted sensory processing.
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Affiliation(s)
- Rune Nguyen Rasmussen
- Center for Translational Neuromedicine, University of Copenhagen, 2200 Copenhagen, Denmark.
| | - Antonis Asiminas
- Center for Translational Neuromedicine, University of Copenhagen, 2200 Copenhagen, Denmark
| | | | - Celia Kjaerby
- Center for Translational Neuromedicine, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Nathan Anthony Smith
- Del Monte Institute for Neuroscience, Department of Neuroscience, University of Rochester, School of Medicine and Dentistry, Rochester, NY 14642, USA.
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13
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Bonato J, Curreli S, Romanzi S, Panzeri S, Fellin T. ASTRA: a deep learning algorithm for fast semantic segmentation of large-scale astrocytic networks. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.03.539211. [PMID: 37205519 PMCID: PMC10187152 DOI: 10.1101/2023.05.03.539211] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Changes in the intracellular calcium concentration are a fundamental fingerprint of astrocytes, the main type of glial cell. Astrocyte calcium signals can be measured with two-photon microscopy, occur in anatomically restricted subcellular regions, and are coordinated across astrocytic networks. However, current analytical tools to identify the astrocytic subcellular regions where calcium signals occur are time-consuming and extensively rely on user-defined parameters. These limitations limit reproducibility and prevent scalability to large datasets and fields-of-view. Here, we present Astrocytic calcium Spatio-Temporal Rapid Analysis (ASTRA), a novel software combining deep learning with image feature engineering for fast and fully automated semantic segmentation of two-photon calcium imaging recordings of astrocytes. We applied ASTRA to several two-photon microscopy datasets and found that ASTRA performed rapid detection and segmentation of astrocytic cell somata and processes with performance close to that of human experts, outperformed state-of-the-art algorithms for the analysis of astrocytic and neuronal calcium data, and generalized across indicators and acquisition parameters. We also applied ASTRA to the first report of two-photon mesoscopic imaging of hundreds of astrocytes in awake mice, documenting large-scale redundant and synergistic interactions in extended astrocytic networks. ASTRA is a powerful tool enabling closed-loop and large-scale reproducible investigation of astrocytic morphology and function.
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Affiliation(s)
- Jacopo Bonato
- Neural Coding Laboratory, Istituto Italiano di Tecnologia; 16163 Genova, Italy
- Department of Pharmacy and Biotechnology, University of Bologna; 40126 Bologna, Italy
- Department of Excellence for Neural Information Processing, Center for Molecular Neurobiology (ZMNH), University Medical Center Hamburg-Eppendorf (UKE), Falkenried 94, D-20251 Hamburg, Germany
| | - Sebastiano Curreli
- Neural Coding Laboratory, Istituto Italiano di Tecnologia; 16163 Genova, Italy
- Optical Approaches to Brain Function Laboratory, Istituto Italiano di Tecnologia; 16163 Genova, Italy
| | - Sara Romanzi
- Neural Coding Laboratory, Istituto Italiano di Tecnologia; 16163 Genova, Italy
- Optical Approaches to Brain Function Laboratory, Istituto Italiano di Tecnologia; 16163 Genova, Italy
- University of Genova; 16126 Genova, Italy
| | - Stefano Panzeri
- Neural Coding Laboratory, Istituto Italiano di Tecnologia; 16163 Genova, Italy
- Department of Excellence for Neural Information Processing, Center for Molecular Neurobiology (ZMNH), University Medical Center Hamburg-Eppendorf (UKE), Falkenried 94, D-20251 Hamburg, Germany
| | - Tommaso Fellin
- Neural Coding Laboratory, Istituto Italiano di Tecnologia; 16163 Genova, Italy
- Optical Approaches to Brain Function Laboratory, Istituto Italiano di Tecnologia; 16163 Genova, Italy
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14
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Barbay T, Pecchi E, Ducrocq M, Rouach N, Brocard F, Bos R. Astrocytic Kir4.1 channels regulate locomotion by orchestrating neuronal rhythmicity in the spinal network. Glia 2023; 71:1259-1277. [PMID: 36645018 DOI: 10.1002/glia.24337] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Revised: 12/22/2022] [Accepted: 01/02/2023] [Indexed: 01/17/2023]
Abstract
Neuronal rhythmogenesis in the spinal cord is correlated with variations in extracellular K+ levels ([K+ ]e ). Astrocytes play important role in [K+ ]e homeostasis and compute neuronal information. Yet it is unclear how neuronal oscillations are regulated by astrocytic K+ homeostasis. Here we identify the astrocytic inward-rectifying K+ channel Kir4.1 (a.k.a. Kcnj10) as a key molecular player for neuronal rhythmicity in the spinal central pattern generator (CPG). By combining two-photon calcium imaging with electrophysiology, immunohistochemistry and genetic tools, we report that astrocytes display Ca2+ transients before and during oscillations of neighboring neurons. Inhibition of astrocytic Ca2+ transients with BAPTA decreases the barium-sensitive Kir4.1 current responsible of K+ clearance. Finally, we show in mice that Kir4.1 knockdown in astrocytes progressively prevents neuronal oscillations and alters the locomotor pattern resulting in lower motor performances in challenging tasks. These data identify astroglial Kir4.1 channels as key regulators of neuronal rhythmogenesis in the CPG driving locomotion.
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Affiliation(s)
- Tony Barbay
- Aix Marseille Univ, CNRS, Institut de Neurosciences de la Timone (INT), UMR 7289, Marseille, France
| | - Emilie Pecchi
- Aix Marseille Univ, CNRS, Institut de Neurosciences de la Timone (INT), UMR 7289, Marseille, France
| | - Myriam Ducrocq
- Aix Marseille Univ, CNRS, Institut de Neurosciences de la Timone (INT), UMR 7289, Marseille, France
| | - Nathalie Rouach
- Center for Interdisciplinary Research in Biology, Collège de France, CNRS, INSERM, Labex Memolife, Université PSL, Paris, France
| | - Frédéric Brocard
- Aix Marseille Univ, CNRS, Institut de Neurosciences de la Timone (INT), UMR 7289, Marseille, France
| | - Rémi Bos
- Aix Marseille Univ, CNRS, Institut de Neurosciences de la Timone (INT), UMR 7289, Marseille, France
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15
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Delgado L, Navarrete M. Shining the Light on Astrocytic Ensembles. Cells 2023; 12:1253. [PMID: 37174653 PMCID: PMC10177371 DOI: 10.3390/cells12091253] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Revised: 04/22/2023] [Accepted: 04/24/2023] [Indexed: 05/15/2023] Open
Abstract
While neurons have traditionally been considered the primary players in information processing, the role of astrocytes in this mechanism has largely been overlooked due to experimental constraints. In this review, we propose that astrocytic ensembles are active working groups that contribute significantly to animal conduct and suggest that studying the maps of these ensembles in conjunction with neurons is crucial for a more comprehensive understanding of behavior. We also discuss available methods for studying astrocytes and argue that these ensembles, complementarily with neurons, code and integrate complex behaviors, potentially specializing in concrete functions.
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Affiliation(s)
| | - Marta Navarrete
- Instituto Cajal, Consejo Superior de Investigaciones Científicas (CSIC), 28002 Madrid, Spain
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16
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Li C, Saliba NB, Martin H, Losurdo NA, Kolahdouzan K, Siddiqui R, Medeiros D, Li W. Purkinje cell dopaminergic inputs to astrocytes regulate cerebellar-dependent behavior. Nat Commun 2023; 14:1613. [PMID: 36959176 PMCID: PMC10036610 DOI: 10.1038/s41467-023-37319-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Accepted: 03/13/2023] [Indexed: 03/25/2023] Open
Abstract
Dopamine has a significant role in motor and cognitive function. The dopaminergic pathways originating from the midbrain have received the most attention; however, the relevance of the cerebellar dopaminergic system is largely undiscovered. Here, we show that the major cerebellar astrocyte type Bergmann glial cells express D1 receptors. Dopamine can be synthesized in Purkinje cells by cytochrome P450 and released in an activity-dependent fashion. We demonstrate that activation of D1 receptors induces membrane depolarization and Ca2+ release from the internal store. These astrocytic activities in turn modify Purkinje cell output by altering its excitatory and inhibitory synaptic input. Lastly, we show that conditional knockout of D1 receptors in Bergmann glial cells results in decreased locomotor activity and impaired social activity. These results contribute to the understanding of the molecular, cellular, and circuit mechanisms underlying dopamine function in the cerebellum, revealing a critical role for the cerebellar dopaminergic system in motor and social behavior.
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Affiliation(s)
- Chang Li
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Natalie B Saliba
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Hannah Martin
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL, USA
- Department of Psychiatry and Psychotherapy, University Medical Center Göttingen, Göttingen, Germany
| | - Nicole A Losurdo
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL, USA
- Neuroscience Program, The University of Utah, Salt Lake City, UT, USA
| | - Kian Kolahdouzan
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Riyan Siddiqui
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Destynie Medeiros
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Wei Li
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL, USA.
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17
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Manninen T, Aćimović J, Linne ML. Analysis of Network Models with Neuron-Astrocyte Interactions. Neuroinformatics 2023; 21:375-406. [PMID: 36959372 PMCID: PMC10085960 DOI: 10.1007/s12021-023-09622-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/01/2023] [Indexed: 03/25/2023]
Abstract
Neural networks, composed of many neurons and governed by complex interactions between them, are a widely accepted formalism for modeling and exploring global dynamics and emergent properties in brain systems. In the past decades, experimental evidence of computationally relevant neuron-astrocyte interactions, as well as the astrocytic modulation of global neural dynamics, have accumulated. These findings motivated advances in computational glioscience and inspired several models integrating mechanisms of neuron-astrocyte interactions into the standard neural network formalism. These models were developed to study, for example, synchronization, information transfer, synaptic plasticity, and hyperexcitability, as well as classification tasks and hardware implementations. We here focus on network models of at least two neurons interacting bidirectionally with at least two astrocytes that include explicitly modeled astrocytic calcium dynamics. In this study, we analyze the evolution of these models and the biophysical, biochemical, cellular, and network mechanisms used to construct them. Based on our analysis, we propose how to systematically describe and categorize interaction schemes between cells in neuron-astrocyte networks. We additionally study the models in view of the existing experimental data and present future perspectives. Our analysis is an important first step towards understanding astrocytic contribution to brain functions. However, more advances are needed to collect comprehensive data about astrocyte morphology and physiology in vivo and to better integrate them in data-driven computational models. Broadening the discussion about theoretical approaches and expanding the computational tools is necessary to better understand astrocytes' roles in brain functions.
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Affiliation(s)
- Tiina Manninen
- Faculty of Medicine and Health Technology, Tampere University, Korkeakoulunkatu 3, FI-33720, Tampere, Finland.
| | - Jugoslava Aćimović
- Faculty of Medicine and Health Technology, Tampere University, Korkeakoulunkatu 3, FI-33720, Tampere, Finland
| | - Marja-Leena Linne
- Faculty of Medicine and Health Technology, Tampere University, Korkeakoulunkatu 3, FI-33720, Tampere, Finland.
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18
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Shekhtmeyster P, Carey EM, Duarte D, Ngo A, Gao G, Nelson NA, Clark CL, Nimmerjahn A. Multiplex translaminar imaging in the spinal cord of behaving mice. Nat Commun 2023; 14:1427. [PMID: 36944637 PMCID: PMC10030868 DOI: 10.1038/s41467-023-36959-2] [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: 12/23/2021] [Accepted: 02/24/2023] [Indexed: 03/23/2023] Open
Abstract
While the spinal cord is known to play critical roles in sensorimotor processing, including pain-related signaling, corresponding activity patterns in genetically defined cell types across spinal laminae have remained challenging to investigate. Calcium imaging has enabled cellular activity measurements in behaving rodents but is currently limited to superficial regions. Here, using chronically implanted microprisms, we imaged sensory and motor-evoked activity in regions and at speeds inaccessible by other high-resolution imaging techniques. To enable translaminar imaging in freely behaving animals through implanted microprisms, we additionally developed wearable microscopes with custom-compound microlenses. This system addresses multiple challenges of previous wearable microscopes, including their limited working distance, resolution, contrast, and achromatic range. Using this system, we show that dorsal horn astrocytes in behaving mice show sensorimotor program-dependent and lamina-specific calcium excitation. Additionally, we show that tachykinin precursor 1 (Tac1)-expressing neurons exhibit translaminar activity to acute mechanical pain but not locomotion.
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Affiliation(s)
- Pavel Shekhtmeyster
- Waitt Advanced Biophotonics Center, The Salk Institute for Biological Studies, La Jolla, CA, 92037, USA
- Electrical and Computer Engineering Graduate Program, University of California, San Diego, La Jolla, CA, 92037, USA
| | - Erin M Carey
- Waitt Advanced Biophotonics Center, The Salk Institute for Biological Studies, La Jolla, CA, 92037, USA
| | - Daniela Duarte
- Waitt Advanced Biophotonics Center, The Salk Institute for Biological Studies, La Jolla, CA, 92037, USA
| | - Alexander Ngo
- Waitt Advanced Biophotonics Center, The Salk Institute for Biological Studies, La Jolla, CA, 92037, USA
| | - Grace Gao
- Waitt Advanced Biophotonics Center, The Salk Institute for Biological Studies, La Jolla, CA, 92037, USA
| | - Nicholas A Nelson
- Waitt Advanced Biophotonics Center, The Salk Institute for Biological Studies, La Jolla, CA, 92037, USA
- Biological Sciences Graduate Program, University of California, San Diego, La Jolla, CA, 92037, USA
| | - Charles L Clark
- Waitt Advanced Biophotonics Center, The Salk Institute for Biological Studies, La Jolla, CA, 92037, USA
| | - Axel Nimmerjahn
- Waitt Advanced Biophotonics Center, The Salk Institute for Biological Studies, La Jolla, CA, 92037, USA.
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19
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Peng W, Liu X, Ma G, Wu Z, Wang Z, Fei X, Qin M, Wang L, Li Y, Zhang S, Xu M. Adenosine-independent regulation of the sleep-wake cycle by astrocyte activity. Cell Discov 2023; 9:16. [PMID: 36746933 PMCID: PMC9902472 DOI: 10.1038/s41421-022-00498-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2022] [Accepted: 11/20/2022] [Indexed: 02/08/2023] Open
Abstract
Astrocytes play a crucial role in regulating sleep-wake behavior, and adenosine signaling is generally thought to be involved. Here we show multiple lines of evidence supporting that modulation of the sleep-wake behavior by astrocyte Ca2+ activity could occur without adenosine signaling. In the basal forebrain and the brainstem, two brain regions that are known to be essential for sleep-wake regulation, chemogenetically-induced astrocyte Ca2+ elevation significantly modulated the sleep-wake cycle. Although astrocyte Ca2+ level positively correlated with the amount of extracellular adenosine, as revealed by a genetically encoded adenosine sensor, we found no detectable change in adenosine level after suppressing astrocyte Ca2+ elevation, and transgenic mice lacking one of the major extracellular ATP-adenosine conversion enzymes showed similar extracellular adenosine level and astrocyte Ca2+-induced sleep modulation. Furthermore, astrocyte Ca2+ is dependent primarily on local neuronal activity, causing brain region-specific regulation of the sleep-wake cycle. Thus, neural activity-dependent astrocyte activity could regulate the sleep-wake behavior independent of adenosine signaling.
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Affiliation(s)
- Wanling Peng
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, China. .,University of Chinese Academy of Sciences, Beijing, China.
| | - Xiaotong Liu
- grid.9227.e0000000119573309Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, China ,grid.410726.60000 0004 1797 8419University of Chinese Academy of Sciences, Beijing, China
| | - Guofen Ma
- grid.16821.3c0000 0004 0368 8293Center for Brain Science of Shanghai Children’s Medical Center, Department of Anatomy and Physiology, Shanghai Jiao Tong University School of Medicine, Shanghai, China ,grid.16821.3c0000 0004 0368 8293Songjiang Institute and Songjiang Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Zhaofa Wu
- grid.11135.370000 0001 2256 9319State Key Laboratory of Membrane Biology, Peking University School of Life Sciences, Beijing, China ,grid.11135.370000 0001 2256 9319Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
| | - Ziyue Wang
- grid.16821.3c0000 0004 0368 8293Center for Brain Science of Shanghai Children’s Medical Center, Department of Anatomy and Physiology, Shanghai Jiao Tong University School of Medicine, Shanghai, China ,grid.16821.3c0000 0004 0368 8293Songjiang Institute and Songjiang Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Xiang Fei
- grid.9227.e0000000119573309Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, China ,grid.410726.60000 0004 1797 8419University of Chinese Academy of Sciences, Beijing, China
| | - Meiling Qin
- grid.9227.e0000000119573309Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, China
| | - Lizhao Wang
- grid.16821.3c0000 0004 0368 8293Center for Brain Science of Shanghai Children’s Medical Center, Department of Anatomy and Physiology, Shanghai Jiao Tong University School of Medicine, Shanghai, China ,grid.16821.3c0000 0004 0368 8293Songjiang Institute and Songjiang Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yulong Li
- grid.11135.370000 0001 2256 9319State Key Laboratory of Membrane Biology, Peking University School of Life Sciences, Beijing, China ,grid.11135.370000 0001 2256 9319Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China ,grid.11135.370000 0001 2256 9319PKU-IDG/McGovern Institute for Brain Research, Beijing, China
| | - Siyu Zhang
- Center for Brain Science of Shanghai Children's Medical Center, Department of Anatomy and Physiology, Shanghai Jiao Tong University School of Medicine, Shanghai, China. .,Songjiang Institute and Songjiang Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
| | - Min Xu
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, China. .,University of Chinese Academy of Sciences, Beijing, China. .,Shanghai Center for Brain Science and Brain-Inspired Intelligence Technology, Shangha, China.
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20
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Lohr C. Role of P2Y receptors in astrocyte physiology and pathophysiology. Neuropharmacology 2023; 223:109311. [PMID: 36328064 DOI: 10.1016/j.neuropharm.2022.109311] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Revised: 10/24/2022] [Accepted: 10/27/2022] [Indexed: 11/07/2022]
Abstract
Astrocytes are active constituents of the brain that manage ion homeostasis and metabolic support of neurons and directly tune synaptic transmission and plasticity. Astrocytes express all known P2Y receptors. These regulate a multitude of physiological functions such as cell proliferation, Ca2+ signalling, gliotransmitter release and neurovascular coupling. In addition, P2Y receptors are fundamental in the transition of astrocytes into reactive astrocytes, as occurring in many brain disorders such as neurodegenerative diseases, neuroinflammation and epilepsy. This review summarizes the current literature addressing the function of P2Y receptors in astrocytes in the healthy brain as well as in brain diseases.
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Affiliation(s)
- Christian Lohr
- Institute of Cell and Systems Biology of Animals, University of Hamburg, Germany.
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21
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de Lima IB, Ribeiro FM. The Implication of Glial Metabotropic Glutamate Receptors in Alzheimer's Disease. Curr Neuropharmacol 2023; 21:164-182. [PMID: 34951388 PMCID: PMC10190153 DOI: 10.2174/1570159x20666211223140303] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Revised: 12/05/2021] [Accepted: 12/16/2021] [Indexed: 11/22/2022] Open
Abstract
Alzheimer's disease (AD) was first identified more than 100 years ago, yet aspects pertaining to its origin and the mechanisms underlying disease progression are not well known. To this date, there is no therapeutic approach or disease-modifying drug that could halt or at least delay disease progression. Until recently, glial cells were seen as secondary actors in brain homeostasis. Although this view was gradually refuted and the relevance of glial cells for the most diverse brain functions such as synaptic plasticity and neurotransmission was vastly proved, many aspects of its functioning, as well as its role in pathological conditions, remain poorly understood. Metabotropic glutamate receptors (mGluRs) in glial cells were shown to be involved in neuroinflammation and neurotoxicity. Besides its relevance for glial function, glutamatergic receptors are also central in the pathology of AD, and recent studies have shown that glial mGluRs play a role in the establishment and progression of AD. AD-related alterations in Ca2+ signalling, APP processing, and Aβ load, as well as AD-related neurodegeneration, are influenced by glial mGluRs. However, different types of mGluRs play different roles, depending on the cell type and brain region that is being analysed. Therefore, in this review, we focus on the current understanding of glial mGluRs and their implication in AD, providing an insight for future therapeutics and identifying existing research gaps worth investigating.
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Affiliation(s)
- Izabella B.Q. de Lima
- Department of Biochemistry and Immunology, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Fabíola M. Ribeiro
- Department of Biochemistry and Immunology, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
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22
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Aghighi Z, Ghorbani Z, Moghaddam MH, Fathi M, Abdollahifar MA, Soleimani M, Karimzadeh F, Rasoolijazi H, Aliaghaei A. Melittin ameliorates motor function and prevents autophagy-induced cell death and astrogliosis in rat models of cerebellar ataxia induced by 3-acetylpyridine. Neuropeptides 2022; 96:102295. [PMID: 36280441 DOI: 10.1016/j.npep.2022.102295] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Revised: 10/10/2022] [Accepted: 10/11/2022] [Indexed: 11/06/2022]
Abstract
BACKGROUND Cerebellar ataxia (CA) is a form of ataxia that adversely affects the cerebellum. This study aims to investigate the therapeutic effects of melittin (MEL) on a 3-acetylpyridine-induced (3-AP) cerebellar ataxia (CA) rat model. METHODS Initially, CA rat models were generated by 3-AP administration followed by the subcutaneous injection of MEL. The open-field test was used for the evaluation of locomotion and anxiety. Immunohistochemistry was also conducted for the autophagy markers of LC3 and Beclin1. In the next step, the morphology of the astrocyte, the cell responsible for maintaining homeostasis in the CNS, was evaluated by the Sholl analysis. RESULTS The findings suggested that the administration of MEL in a 3-AP model of ataxia improved locomotion and anxiety (P < 0.001), decreased the expression of LC3 (P < 0.01) and Beclin1 (P < 0.05), increased astrocyte complexity (P < 0.05) and reduced astrocyte cell soma size (P < 0.001). CONCLUSIONS Overall, the findings imply that the MEL attenuates the 3-AP-induced autophagy, causes cell death and improves motor function. As such, it could be used as a therapeutic procedure for CA due to its neuroprotective effects.
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Affiliation(s)
- Zahra Aghighi
- Department of Anatomy, School of Medicine, Iran University of Medical Sciences, Tehran, Iran; Cellular and Molecular Research Center, Iran University of Medical Sciences, Tehran, Iran
| | - Zeynab Ghorbani
- Department of Anatomy, School of Medicine, Iran University of Medical Sciences, Tehran, Iran; Cellular and Molecular Research Center, Iran University of Medical Sciences, Tehran, Iran
| | - Meysam Hassani Moghaddam
- Department of Anatomical Sciences, Faculty of Medicine, AJA University of Medical Sciences, Tehran, Iran
| | - Mobina Fathi
- Student Research Committee, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Mohammad-Amin Abdollahifar
- Department of Biology and Anatomical Sciences, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Mansoureh Soleimani
- Department of Anatomy, School of Medicine, Iran University of Medical Sciences, Tehran, Iran; Cellular and Molecular Research Center, Iran University of Medical Sciences, Tehran, Iran
| | - Fariba Karimzadeh
- Cellular and Molecular Research Center, Iran University of Medical Sciences, Tehran, Iran
| | - Homa Rasoolijazi
- Department of Anatomy, School of Medicine, Iran University of Medical Sciences, Tehran, Iran; Cellular and Molecular Research Center, Iran University of Medical Sciences, Tehran, Iran.
| | - Abbas Aliaghaei
- Hearing Disorders Research Center, Loghman Hakim Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran; Department of Biology and Anatomical Sciences, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
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23
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Kruyer A. Astrocyte Heterogeneity in Regulation of Synaptic Activity. Cells 2022; 11:cells11193135. [PMID: 36231097 PMCID: PMC9562199 DOI: 10.3390/cells11193135] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Revised: 10/02/2022] [Accepted: 10/02/2022] [Indexed: 02/07/2023] Open
Abstract
Our awareness of the number of synapse regulatory functions performed by astroglia is rapidly expanding, raising interesting questions regarding astrocyte heterogeneity and specialization across brain regions. Whether all astrocytes are poised to signal in a multitude of ways, or are instead tuned to surrounding synapses and how astroglial signaling is altered in psychiatric and cognitive disorders are fundamental questions for the field. In recent years, molecular and morphological characterization of astroglial types has broadened our ability to design studies to better analyze and manipulate specific functions of astroglia. Recent data emerging from these studies will be discussed in depth in this review. I also highlight remaining questions emerging from new techniques recently applied toward understanding the roles of astrocytes in synapse regulation in the adult brain.
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Affiliation(s)
- Anna Kruyer
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC 29425, USA
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24
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Men Y, Higashimori H, Reynolds K, Tu L, Jarvis R, Yang Y. Functionally Clustered mRNAs Are Distinctly Enriched at Cortical Astroglial Processes and Are Preferentially Affected by FMRP Deficiency. J Neurosci 2022; 42:5803-5814. [PMID: 35701158 PMCID: PMC9302465 DOI: 10.1523/jneurosci.0274-22.2022] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Revised: 05/06/2022] [Accepted: 06/08/2022] [Indexed: 01/22/2023] Open
Abstract
Mature protoplasmic astroglia in the mammalian CNS uniquely possess a large number of fine processes that have been considered primary sites to mediate astroglia to neuron synaptic signaling. However, localized mechanisms for regulating interactions between astroglial processes and synapses, especially for regulating the expression of functional surface proteins at these fine processes, are largely unknown. Previously, we showed that the loss of the RNA binding protein FMRP in astroglia disrupts astroglial mGluR5 signaling and reduces expression of the major astroglial glutamate transporter GLT1 and glutamate uptake in the cortex of Fmr1 conditional deletion mice. In the current study, by examining ribosome localization using electron microscopy and identifying mRNAs enriched at cortical astroglial processes using synaptoneurosome/translating ribosome affinity purification and RNA-Seq in WT and FMRP-deficient male mice, our results reveal interesting localization-dependent functional clusters of mRNAs at astroglial processes. We further showed that the lack of FMRP preferentially alters the subcellular localization and expression of process-localized mRNAs. Together, we defined the role of FMRP in altering mRNA localization and expression at astroglial processes at the postnatal development (P30-P40) and provided new candidate mRNAs that are potentially regulated by FMRP in cortical astroglia.SIGNIFICANCE STATEMENT Localized mechanisms for regulating interactions between astroglial processes and synapses, especially for regulating the expression of functional surface proteins at these fine processes, are largely unknown. Previously, we showed that the loss of the RNA binding protein FMRP in astroglia disrupts expression of several astroglial surface proteins, such as mGluR5 and major astroglial glutamate transporter GLT1 in the cortex of FMRP-deficient mice. Our current study examined ribosome localization using electron microscopy and identified mRNAs enriched at cortical astroglial processes in WT and FMRP-deficient mice. These results reveal interesting localization-dependent functional clusters of mRNAs at astroglial processes and demonstrate that the lack of FMRP preferentially alters the subcellular localization and expression of process-localized mRNAs.
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Affiliation(s)
- Yuqin Men
- Department of Neuroscience, Tufts University School of Medicine, Boston, Massachusetts 02111
| | - Haruki Higashimori
- Department of Neuroscience, Tufts University School of Medicine, Boston, Massachusetts 02111
| | - Kathryn Reynolds
- Department of Neuroscience, Tufts University School of Medicine, Boston, Massachusetts 02111
| | - Leona Tu
- Department of Neuroscience, Tufts University School of Medicine, Boston, Massachusetts 02111
| | - Rachel Jarvis
- Department of Neuroscience, Tufts University School of Medicine, Boston, Massachusetts 02111
| | - Yongjie Yang
- Department of Neuroscience, Tufts University School of Medicine, Boston, Massachusetts 02111
- Graduate School of Biomedical Sciences, Tufts University, Boston, Massachusetts 02111
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25
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Ward S, Riley C, Carey EM, Nguyen J, Esener S, Nimmerjahn A, Sirbuly DJ. Electro-optical mechanically flexible coaxial microprobes for minimally invasive interfacing with intrinsic neural circuits. Nat Commun 2022; 13:3286. [PMID: 35672294 PMCID: PMC9174211 DOI: 10.1038/s41467-022-30275-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Accepted: 04/22/2022] [Indexed: 12/17/2022] Open
Abstract
Central to advancing our understanding of neural circuits is developing minimally invasive, multi-modal interfaces capable of simultaneously recording and modulating neural activity. Recent devices have focused on matching the mechanical compliance of tissue to reduce inflammatory responses. However, reductions in the size of multi-modal interfaces are needed to further improve biocompatibility and long-term recording capabilities. Here a multi-modal coaxial microprobe design with a minimally invasive footprint (8-14 µm diameter over millimeter lengths) that enables efficient electrical and optical interrogation of neural networks is presented. In the brain, the probes allowed robust electrical measurement and optogenetic stimulation. Scalable fabrication strategies can be used with various electrical and optical materials, making the probes highly customizable to experimental requirements, including length, diameter, and mechanical properties. Given their negligible inflammatory response, these probes promise to enable a new generation of readily tunable multi-modal devices for long-term, minimally invasive interfacing with neural circuits.
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Affiliation(s)
- Spencer Ward
- Department of Electrical and Computer Engineering, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Conor Riley
- Department of Nanoengineering, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Erin M Carey
- Waitt Advanced Biophotonics Center, Salk Institute for Biological Studies, La Jolla, CA, 92037, USA
| | - Jenny Nguyen
- Department of Nanoengineering, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Sadik Esener
- Department of Electrical and Computer Engineering, University of California, San Diego, La Jolla, CA, 92093, USA
- Department of Nanoengineering, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Axel Nimmerjahn
- Waitt Advanced Biophotonics Center, Salk Institute for Biological Studies, La Jolla, CA, 92037, USA.
| | - Donald J Sirbuly
- Department of Nanoengineering, University of California, San Diego, La Jolla, CA, 92093, USA.
- Materials Science and Engineering, University of California, San Diego, La Jolla, CA, 92093, USA.
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26
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Reinforcing Interdisciplinary Collaborations to Unravel the Astrocyte "Calcium Code". J Mol Neurosci 2022; 72:1443-1455. [PMID: 35543801 PMCID: PMC9293817 DOI: 10.1007/s12031-022-02006-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Accepted: 04/01/2022] [Indexed: 11/19/2022]
Abstract
In this review article, we present the major insights from and challenges faced in the acquisition, analysis and modeling of astrocyte calcium activity, aiming at bridging the gap between those fields to crack the complex astrocyte “Calcium Code”. We then propose strategies to reinforce interdisciplinary collaborative projects to unravel astrocyte function in health and disease.
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27
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Zhang Q, Turner KL, Gheres KW, Hossain MS, Drew PJ. Behavioral and physiological monitoring for awake neurovascular coupling experiments: a how-to guide. NEUROPHOTONICS 2022; 9:021905. [PMID: 35639834 PMCID: PMC8802326 DOI: 10.1117/1.nph.9.2.021905] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Accepted: 12/28/2021] [Indexed: 06/15/2023]
Abstract
Significance: Functional brain imaging in awake animal models is a popular and powerful technique that allows the investigation of neurovascular coupling (NVC) under physiological conditions. However, ubiquitous facial and body motions (fidgeting) are prime drivers of spontaneous fluctuations in neural and hemodynamic signals. During periods without movement, animals can rapidly transition into sleep, and the hemodynamic signals tied to arousal state changes can be several times larger than sensory-evoked responses. Given the outsized influence of facial and body motions and arousal signals in neural and hemodynamic signals, it is imperative to detect and monitor these events in experiments with un-anesthetized animals. Aim: To cover the importance of monitoring behavioral state in imaging experiments using un-anesthetized rodents, and describe how to incorporate detailed behavioral and physiological measurements in imaging experiments. Approach: We review the effects of movements and sleep-related signals (heart rate, respiration rate, electromyography, intracranial pressure, whisking, and other body movements) on brain hemodynamics and electrophysiological signals, with a focus on head-fixed experimental setup. We summarize the measurement methods currently used in animal models for detection of those behaviors and arousal changes. We then provide a guide on how to incorporate this measurements with functional brain imaging and electrophysiology measurements. Results: We provide a how-to guide on monitoring and interpreting a variety of physiological signals and their applications to NVC experiments in awake behaving mice. Conclusion: This guide facilitates the application of neuroimaging in awake animal models and provides neuroscientists with a standard approach for monitoring behavior and other associated physiological parameters in head-fixed animals.
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Affiliation(s)
- Qingguang Zhang
- The Pennsylvania State University, Center for Neural Engineering, Department of Engineering Science and Mechanics, University Park, Pennsylvania, United States
| | - Kevin L. Turner
- The Pennsylvania State University, Department of Biomedical Engineering, University Park, Pennsylvania, United States
| | - Kyle W. Gheres
- The Pennsylvania State University, Graduate Program in Molecular Cellular and Integrative Biosciences, University Park, Pennsylvania, United States
| | - Md Shakhawat Hossain
- The Pennsylvania State University, Department of Biomedical Engineering, University Park, Pennsylvania, United States
| | - Patrick J. Drew
- The Pennsylvania State University, Center for Neural Engineering, Department of Engineering Science and Mechanics, University Park, Pennsylvania, United States
- The Pennsylvania State University, Department of Biomedical Engineering, University Park, Pennsylvania, United States
- The Pennsylvania State University, Department of Neurosurgery, University Park, Pennsylvania, United States
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28
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Hirrlinger J, Nimmerjahn A. A perspective on astrocyte regulation of neural circuit function and animal behavior. Glia 2022; 70:1554-1580. [PMID: 35297525 PMCID: PMC9291267 DOI: 10.1002/glia.24168] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Revised: 01/19/2022] [Accepted: 02/27/2022] [Indexed: 12/16/2022]
Abstract
Studies over the past two decades have demonstrated that astrocytes are
tightly associated with neurons and play pivotal roles in neural circuit
development, operation, and adaptation in health and disease. Nevertheless,
precisely how astrocytes integrate diverse neuronal signals, modulate neural
circuit structure and function at multiple temporal and spatial scales, and
influence animal behavior or disease through aberrant excitation and molecular
output remains unclear. This Perspective discusses how new and state-of-the-art
approaches, including fluorescence indicators, opto- and chemogenetic actuators,
genetic targeting tools, quantitative behavioral assays, and computational
methods, might help resolve these longstanding questions. It also addresses
complicating factors in interpreting astrocytes’ role in neural circuit
regulation and animal behavior, such as their heterogeneity, metabolism, and
inter-glial communication. Research on these questions should provide a deeper
mechanistic understanding of astrocyte-neuron assemblies’ role in neural
circuit function, complex behaviors, and disease.
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Affiliation(s)
- Johannes Hirrlinger
- Carl-Ludwig-Institute for Physiology, Medical Faculty, University of Leipzig, Leipzig, Germany.,Department of Neurogenetics, Max-Planck-Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Axel Nimmerjahn
- Waitt Advanced Biophotonics Center, The Salk Institute for Biological Studies, La Jolla, California
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29
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Del Franco AP, Chiang PP, Newman EA. Dilation of cortical capillaries is not related to astrocyte calcium signaling. Glia 2022; 70:508-521. [PMID: 34767261 PMCID: PMC8732319 DOI: 10.1002/glia.24119] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Revised: 10/12/2021] [Accepted: 10/31/2021] [Indexed: 12/30/2022]
Abstract
The brain requires an adequate supply of oxygen and nutrients to maintain proper function as neuronal activity varies. This is achieved, in part, through neurovascular coupling mechanisms that mediate local increases in blood flow through the dilation of arterioles and capillaries. The role of astrocytes in mediating this functional hyperemia response is controversial. Specifically, the function of astrocyte Ca2+ signaling is unclear. Cortical arterioles dilate in the absence of astrocyte Ca2+ signaling, but previous work suggests that Ca2+ increases are necessary for capillary dilation. This question has not been fully addressed in vivo, however, and we have reexamined the role of astrocyte Ca2+ signaling in vessel dilation in the barrel cortex of awake, behaving mice. We recorded evoked vessel dilations and astrocyte Ca2+ signaling in response to whisker stimulation. Experiments were carried out on WT and IP3R2 KO mice, a transgenic model where astrocyte Ca2+ signaling is substantially reduced. Compared to WT mice at rest, Ca2+ signaling in astrocyte endfeet contacting capillaries increased by 240% when whisker stimulation evoked running. In contrast, Ca2+ signaling was reduced to 9% of WT values in IP3R2 KO mice. In all three conditions, however, the amplitude of capillary dilation was largely unchanged. In addition, the latency to the onset of astrocyte Ca2+ signaling lagged behind dilation onset in most trials, although a subset of rapid onset Ca2+ events with latencies as short as 0.15 s occurred. In summary, we found that whisker stimulation-evoked capillary dilations occurred independent of astrocyte Ca2+ increases in the cerebral cortex.
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Affiliation(s)
- Armani P Del Franco
- Department of Neuroscience, University of Minnesota, Minneapolis, Minnesota, USA
| | - Pei-Pei Chiang
- Department of Neuroscience, University of Minnesota, Minneapolis, Minnesota, USA
| | - Eric A Newman
- Department of Neuroscience, University of Minnesota, Minneapolis, Minnesota, USA
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30
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Lyon KA, Allen NJ. From Synapses to Circuits, Astrocytes Regulate Behavior. Front Neural Circuits 2022; 15:786293. [PMID: 35069124 PMCID: PMC8772456 DOI: 10.3389/fncir.2021.786293] [Citation(s) in RCA: 36] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Accepted: 11/05/2021] [Indexed: 12/21/2022] Open
Abstract
Astrocytes are non-neuronal cells that regulate synapses, neuronal circuits, and behavior. Astrocytes ensheath neuronal synapses to form the tripartite synapse where astrocytes influence synapse formation, function, and plasticity. Beyond the synapse, recent research has revealed that astrocyte influences on the nervous system extend to the modulation of neuronal circuitry and behavior. Here we review recent findings on the active role of astrocytes in behavioral modulation with a focus on in vivo studies, primarily in mice. Using tools to acutely manipulate astrocytes, such as optogenetics or chemogenetics, studies reviewed here have demonstrated a causal role for astrocytes in sleep, memory, sensorimotor behaviors, feeding, fear, anxiety, and cognitive processes like attention and behavioral flexibility. Current tools and future directions for astrocyte-specific manipulation, including methods for probing astrocyte heterogeneity, are discussed. Understanding the contribution of astrocytes to neuronal circuit activity and organismal behavior will be critical toward understanding how nervous system function gives rise to behavior.
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Affiliation(s)
- Krissy A Lyon
- Molecular Neurobiology Laboratory, The Salk Institute for Biological Studies, La Jolla, CA, United States
| | - Nicola J Allen
- Molecular Neurobiology Laboratory, The Salk Institute for Biological Studies, La Jolla, CA, United States
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31
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Gray SR, Ye L, Ye JY, Paukert M. Noradrenergic terminal short-term potentiation enables modality-selective integration of sensory input and vigilance state. SCIENCE ADVANCES 2021; 7:eabk1378. [PMID: 34919424 PMCID: PMC8682997 DOI: 10.1126/sciadv.abk1378] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Accepted: 10/28/2021] [Indexed: 06/14/2023]
Abstract
Recent years have seen compelling demonstrations of the importance of behavioral state on sensory processing and attention. Arousal plays a dominant role in controlling brain-wide neural activity patterns, particularly through modulation by norepinephrine. Noradrenergic brainstem nuclei, including locus coeruleus, can be activated by stimuli of multiple sensory modalities and broadcast modulatory signals via axonal projections throughout the brain. This organization might suggest proportional brain-wide norepinephrine release during states of heightened vigilance. Here, however, we have found that low-intensity, nonarousing visual stimuli enhanced vigilance-dependent noradrenergic signaling locally in visual cortex, revealed using dual-site fiber photometry to monitor noradrenergic Ca2+ responses of astroglia simultaneously in cerebellum and visual cortex and two-photon microscopy to monitor noradrenergic axonal terminal Ca2+ dynamics. Nitric oxide, following N-methyl-d-aspartate receptor activation in neuronal nitric oxide synthase-positive interneurons, mediated transient acceleration of norepinephrine-dependent astroglia Ca2+ activation. These findings reveal a candidate cortical microcircuit for sensory modality-selective modulation of attention.
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Affiliation(s)
- Shawn R. Gray
- Department of Cellular and Integrative Physiology, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA
- Joint UTSA/UTHSCSA Graduate Program in Biomedical Engineering, San Antonio, TX, USA
| | - Liang Ye
- Department of Cellular and Integrative Physiology, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA
| | - Jing Yong Ye
- Joint UTSA/UTHSCSA Graduate Program in Biomedical Engineering, San Antonio, TX, USA
- Department of Biomedical Engineering, University of Texas at San Antonio, San Antonio, TX, USA
| | - Martin Paukert
- Department of Cellular and Integrative Physiology, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA
- Joint UTSA/UTHSCSA Graduate Program in Biomedical Engineering, San Antonio, TX, USA
- Center for Biomedical Neuroscience, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA
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32
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Pereida-Jaramillo E, Gómez-González GB, Espino-Saldaña AE, Martínez-Torres A. Calcium Signaling in the Cerebellar Radial Glia and Its Association with Morphological Changes during Zebrafish Development. Int J Mol Sci 2021; 22:ijms222413509. [PMID: 34948305 PMCID: PMC8706707 DOI: 10.3390/ijms222413509] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Revised: 12/08/2021] [Accepted: 12/12/2021] [Indexed: 01/02/2023] Open
Abstract
Radial glial cells are a distinct non-neuronal cell type that, during development, span the entire width of the brain walls of the ventricular system. They play a central role in the origin and placement of neurons, since their processes form structural scaffolds that guide and facilitate neuronal migration. Furthermore, glutamatergic signaling in the radial glia of the adult cerebellum (i.e., Bergmann glia), is crucial for precise motor coordination. Radial glial cells exhibit spontaneous calcium activity and functional coupling spread calcium waves. However, the origin of calcium activity in relation to the ontogeny of cerebellar radial glia has not been widely explored, and many questions remain unanswered regarding the role of radial glia in brain development in health and disease. In this study we used a combination of whole mount immunofluorescence and calcium imaging in transgenic (gfap-GCaMP6s) zebrafish to determine how development of calcium activity is related to morphological changes of the cerebellum. We found that the morphological changes in cerebellar radial glia are quite dynamic; the cells are remarkably larger and more elaborate in their soma size, process length and numbers after 7 days post fertilization. Spontaneous calcium events were scarce during the first 3 days of development and calcium waves appeared on day 5, which is associated with the onset of more complex morphologies of radial glia. Blockage of gap junction coupling inhibited the propagation of calcium waves, but not basal local calcium activity. This work establishes crucial clues in radial glia organization, morphology and calcium signaling during development and provides insight into its role in complex behavioral paradigms.
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33
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Astiz M, Delgado-García LM, López-Mascaraque L. Astrocytes as essential time-keepers of the central pacemaker. Glia 2021; 70:808-819. [PMID: 34816453 DOI: 10.1002/glia.24121] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Revised: 11/10/2021] [Accepted: 11/12/2021] [Indexed: 12/13/2022]
Abstract
Since the early observations made by Santiago Ramon y Cajal more than a century ago till now, astrocytes have gradually gained protagonism as essential partners of neurons in building brain circuits that regulate complex behavior. In mammals, processes such as sleep-wake cycle, locomotor activity, cognition and memory consolidation, homeostatic and hedonic appetite and stress response (among others), are synchronized in 24-h rhythms by the circadian system. In such a way, physiology efficiently anticipates and adapts to daily recurring changes in the environment. The hypothalamic suprachiasmatic nucleus (SCN) is considered the central pacemaker, it has been traditionally described as a nucleus of around 10,000 neurons nearly all GABAergic able to be entrained by light and to convey time information through multiple neuronal and hormonal pathways. Only recently, this neuro-centered view was challenged by breakthrough discoveries implicating astrocytes as essential time-keepers. In the present review, we will describe the current view on the SCN circuit and discuss whether astrocytic functions described in other brain regions and state-of-the-art experimental approaches, could help explaining better those well- and not so well-known features of the central pacemaker.
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Affiliation(s)
- Mariana Astiz
- Institute of Neurobiology, Center of Brain, Behavior and Metabolism (CBBM), University of Lübeck, Lübeck, Germany
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34
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A human iPSC-astroglia neurodevelopmental model reveals divergent transcriptomic patterns in schizophrenia. Transl Psychiatry 2021; 11:554. [PMID: 34716291 PMCID: PMC8556332 DOI: 10.1038/s41398-021-01681-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/20/2021] [Revised: 09/20/2021] [Accepted: 10/01/2021] [Indexed: 12/17/2022] Open
Abstract
While neurodevelopmental abnormalities have been associated with schizophrenia (SCZ), the role of astroglia in disease pathophysiology remains poorly understood. In the present study, we used a human induced pluripotent stem cell (iPSC)-derived astrocyte model to investigate the temporal patterns of astroglia differentiation during developmental stages critical for SCZ using RNA sequencing. The model generated astrocyte-specific gene expression patterns during differentiation that corresponded well to astroglia-specific expression signatures of in vivo cortical fetal development. Using this model we identified SCZ-specific expression dynamics, and found that SCZ-associated differentially expressed genes were significantly enriched in the medial prefrontal cortex, striatum, and temporal lobe, targeting VWA5A and ADAMTS19. In addition, SCZ astrocytes displayed alterations in calcium signaling, and significantly decreased glutamate uptake and metalloproteinase activity relative to controls. These results implicate novel transcriptional dynamics in astrocyte differentiation in SCZ together with functional changes that are potentially important biological components of SCZ pathology.
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35
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Benfey NJ, Li VJ, Schohl A, Ruthazer ES. Sodium-calcium exchanger mediates sensory-evoked glial calcium transients in the developing retinotectal system. Cell Rep 2021; 37:109791. [PMID: 34610307 DOI: 10.1016/j.celrep.2021.109791] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Revised: 06/24/2021] [Accepted: 09/13/2021] [Indexed: 12/14/2022] Open
Abstract
Various types of sensory stimuli have been shown to induce Ca2+ elevations in glia. However, a mechanistic understanding of the signaling pathways mediating sensory-evoked activity in glia in intact animals is still emerging. During early development of the Xenopus laevis visual system, radial astrocytes in the optic tectum are highly responsive to sensory stimulation. Ca2+ transients occur spontaneously in radial astrocytes at rest and are abolished by silencing neuronal activity with tetrodotoxin. Visual stimulation drives temporally correlated increases in the activity patterns of neighboring radial astrocytes. Following blockade of all glutamate receptors (gluRs), visually evoked Ca2+ activity in radial astrocytes persists, while neuronal activity is suppressed. The additional blockade of either glu transporters or sodium-calcium exchangers (NCX) abolishes visually evoked responses in glia. Finally, we demonstrate that blockade of NCX alone is sufficient to prevent visually evoked responses in radial astrocytes, highlighting a pivotal role for NCX in glia during development.
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Affiliation(s)
- Nicholas J Benfey
- Montreal Neurological Institute-Hospital, Department of Neurology and Neurosurgery, McGill University, Montréal, Québec, H3A 2B4 Canada
| | - Vanessa J Li
- Montreal Neurological Institute-Hospital, Department of Neurology and Neurosurgery, McGill University, Montréal, Québec, H3A 2B4 Canada
| | - Anne Schohl
- Montreal Neurological Institute-Hospital, Department of Neurology and Neurosurgery, McGill University, Montréal, Québec, H3A 2B4 Canada
| | - Edward S Ruthazer
- Montreal Neurological Institute-Hospital, Department of Neurology and Neurosurgery, McGill University, Montréal, Québec, H3A 2B4 Canada.
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36
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Liu X, Ying J, Wang X, Zheng Q, Zhao T, Yoon S, Yu W, Yang D, Fang Y, Hua F. Astrocytes in Neural Circuits: Key Factors in Synaptic Regulation and Potential Targets for Neurodevelopmental Disorders. Front Mol Neurosci 2021; 14:729273. [PMID: 34658786 PMCID: PMC8515196 DOI: 10.3389/fnmol.2021.729273] [Citation(s) in RCA: 11] [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: 07/02/2021] [Accepted: 09/02/2021] [Indexed: 12/14/2022] Open
Abstract
Astrocytes are the major glial cells in the brain, which play a supporting role in the energy and nutritional supply of neurons. They were initially regarded as passive space-filling cells, but the latest progress in the study of the development and function of astrocytes highlights their active roles in regulating synaptic transmission, formation, and plasticity. In the concept of "tripartite synapse," the bidirectional influence between astrocytes and neurons, in addition to their steady-state and supporting function, suggests that any negative changes in the structure or function of astrocytes will affect the activity of neurons, leading to neurodevelopmental disorders. The role of astrocytes in the pathophysiology of various neurological and psychiatric disorders caused by synaptic defects is increasingly appreciated. Understanding the roles of astrocytes in regulating synaptic development and the plasticity of neural circuits could help provide new treatments for these diseases.
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Affiliation(s)
- Xing Liu
- Department of Anesthesiology, The Second Affiliated Hospital of Nanchang University, Nanchang, China
- Key Laboratory of Anesthesiology of Jiangxi Province, Nanchang, China
| | - Jun Ying
- Department of Anesthesiology, The Second Affiliated Hospital of Nanchang University, Nanchang, China
- Key Laboratory of Anesthesiology of Jiangxi Province, Nanchang, China
| | - Xifeng Wang
- Department of Anesthesiology, The First Affiliated Hospital of Nanchang University, Nanchang, China
| | - Qingcui Zheng
- Department of Anesthesiology, The Second Affiliated Hospital of Nanchang University, Nanchang, China
- Key Laboratory of Anesthesiology of Jiangxi Province, Nanchang, China
| | - Tiancheng Zhao
- Mailman School of Public Health, Columbia University, New York, NY, United States
| | - Sungtae Yoon
- Helping Minds International Charitable Foundation, New York, NY, United States
| | - Wen Yu
- Department of Anesthesiology, The Second Affiliated Hospital of Nanchang University, Nanchang, China
- Key Laboratory of Anesthesiology of Jiangxi Province, Nanchang, China
| | - Danying Yang
- Department of Anesthesiology, The Second Affiliated Hospital of Nanchang University, Nanchang, China
- Key Laboratory of Anesthesiology of Jiangxi Province, Nanchang, China
| | - Yang Fang
- Department of Anesthesiology, The Second Affiliated Hospital of Nanchang University, Nanchang, China
- Key Laboratory of Anesthesiology of Jiangxi Province, Nanchang, China
| | - Fuzhou Hua
- Department of Anesthesiology, The Second Affiliated Hospital of Nanchang University, Nanchang, China
- Key Laboratory of Anesthesiology of Jiangxi Province, Nanchang, China
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Schweigmann M, Caudal LC, Stopper G, Scheller A, Koch KP, Kirchhoff F. Versatile Surface Electrodes for Combined Electrophysiology and Two-Photon Imaging of the Mouse Central Nervous System. Front Cell Neurosci 2021; 15:720675. [PMID: 34447299 PMCID: PMC8383317 DOI: 10.3389/fncel.2021.720675] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Accepted: 07/19/2021] [Indexed: 11/23/2022] Open
Abstract
Understanding and modulating CNS function in physiological as well as pathophysiological contexts remains a significant ambition in research and clinical applications. The investigation of the multifaceted CNS cell types including their interactions and contributions to neural function requires a combination of the state-of-the-art in vivo electrophysiology and imaging techniques. We developed a novel type of liquid crystal polymer (LCP) surface micro-electrode manufactured in three customized designs with up to 16 channels for recording and stimulation of brain activity. All designs include spare central spaces for simultaneous 2P-imaging. Nanoporous platinum-plated contact sites ensure a low impedance and high current transfer. The epidural implantation of the LCP micro-electrodes could be combined with standard cranial window surgery. The epidurally positioned electrodes did not only display long-term biocompatibility, but we also observed an additional stabilization of the underlying CNS tissue. We demonstrate the electrode’s versatility in combination with in vivo 2P-imaging by monitoring anesthesia-awake cycles of transgenic mice with GCaMP3 expression in neurons or astrocytes. Cortical stimulation and simultaneous 2P Ca2+ imaging in neurons or astrocytes highlighted the astrocytes’ integrative character in neuronal activity processing. Furthermore, we confirmed that spontaneous astroglial Ca2+ signals are dampened under anesthesia, while evoked signals in neurons and astrocytes showed stronger dependency on stimulation intensity rather than on various levels of anesthesia. Finally, we show that the electrodes provide recordings of the electrocorticogram (ECoG) with a high signal-to noise ratio and spatial signal differences which help to decipher brain activity states during experimental procedures. Summarizing, the novel LCP surface micro-electrode is a versatile, convenient, and reliable tool to investigate brain function in vivo.
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Affiliation(s)
- Michael Schweigmann
- Molecular Physiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), University of Saarland, Homburg, Germany.,Department of Electrical Engineering, Trier University of Applied Sciences, Trier, Germany
| | - Laura C Caudal
- Molecular Physiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), University of Saarland, Homburg, Germany
| | - Gebhard Stopper
- Molecular Physiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), University of Saarland, Homburg, Germany
| | - Anja Scheller
- Molecular Physiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), University of Saarland, Homburg, Germany
| | - Klaus P Koch
- Department of Electrical Engineering, Trier University of Applied Sciences, Trier, Germany
| | - Frank Kirchhoff
- Molecular Physiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), University of Saarland, Homburg, Germany
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Wagner MJ, Savall J, Hernandez O, Mel G, Inan H, Rumyantsev O, Lecoq J, Kim TH, Li JZ, Ramakrishnan C, Deisseroth K, Luo L, Ganguli S, Schnitzer MJ. A neural circuit state change underlying skilled movements. Cell 2021; 184:3731-3747.e21. [PMID: 34214470 PMCID: PMC8844704 DOI: 10.1016/j.cell.2021.06.001] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Revised: 05/09/2021] [Accepted: 06/01/2021] [Indexed: 11/21/2022]
Abstract
In motor neuroscience, state changes are hypothesized to time-lock neural assemblies coordinating complex movements, but evidence for this remains slender. We tested whether a discrete change from more autonomous to coherent spiking underlies skilled movement by imaging cerebellar Purkinje neuron complex spikes in mice making targeted forelimb-reaches. As mice learned the task, millimeter-scale spatiotemporally coherent spiking emerged ipsilateral to the reaching forelimb, and consistent neural synchronization became predictive of kinematic stereotypy. Before reach onset, spiking switched from more disordered to internally time-locked concerted spiking and silence. Optogenetic manipulations of cerebellar feedback to the inferior olive bi-directionally modulated neural synchronization and reaching direction. A simple model explained the reorganization of spiking during reaching as reflecting a discrete bifurcation in olivary network dynamics. These findings argue that to prepare learned movements, olivo-cerebellar circuits enter a self-regulated, synchronized state promoting motor coordination. State changes facilitating behavioral transitions may generalize across neural systems.
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Affiliation(s)
- Mark J Wagner
- Neurosciences Program, Stanford University, Stanford, CA 94305, USA; Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305, USA; CNC Program, Stanford University, Stanford, CA 94305, USA; Department of Biology, Stanford University, Stanford, CA 94305, USA.
| | - Joan Savall
- Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305, USA; CNC Program, Stanford University, Stanford, CA 94305, USA
| | | | - Gabriel Mel
- Neurosciences Program, Stanford University, Stanford, CA 94305, USA
| | - Hakan Inan
- CNC Program, Stanford University, Stanford, CA 94305, USA; Department of Electrical Engineering, Stanford University, Stanford, CA 94305, USA
| | - Oleg Rumyantsev
- CNC Program, Stanford University, Stanford, CA 94305, USA; Department of Applied Physics, Stanford University, Stanford, CA 94305, USA
| | - Jérôme Lecoq
- CNC Program, Stanford University, Stanford, CA 94305, USA; Department of Biology, Stanford University, Stanford, CA 94305, USA
| | - Tony Hyun Kim
- Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305, USA; CNC Program, Stanford University, Stanford, CA 94305, USA; Department of Electrical Engineering, Stanford University, Stanford, CA 94305, USA
| | - Jin Zhong Li
- CNC Program, Stanford University, Stanford, CA 94305, USA; Department of Biology, Stanford University, Stanford, CA 94305, USA
| | - Charu Ramakrishnan
- Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305, USA; Department of Bioengineering, Stanford University, Stanford, CA 94305, USA
| | - Karl Deisseroth
- Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305, USA; Department of Bioengineering, Stanford University, Stanford, CA 94305, USA
| | - Liqun Luo
- Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305, USA; Department of Biology, Stanford University, Stanford, CA 94305, USA
| | - Surya Ganguli
- Department of Applied Physics, Stanford University, Stanford, CA 94305, USA
| | - Mark J Schnitzer
- Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305, USA; CNC Program, Stanford University, Stanford, CA 94305, USA; Department of Biology, Stanford University, Stanford, CA 94305, USA; Department of Applied Physics, Stanford University, Stanford, CA 94305, USA.
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Tsunematsu T, Sakata S, Sanagi T, Tanaka KF, Matsui K. Region-Specific and State-Dependent Astrocyte Ca 2+ Dynamics during the Sleep-Wake Cycle in Mice. J Neurosci 2021; 41:5440-5452. [PMID: 34006590 PMCID: PMC8221592 DOI: 10.1523/jneurosci.2912-20.2021] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Revised: 04/06/2021] [Accepted: 05/02/2021] [Indexed: 11/21/2022] Open
Abstract
Neural activity is diverse, and varies depending on brain regions and sleep/wakefulness states. However, whether astrocyte activity differs between sleep/wakefulness states, and whether there are differences in astrocyte activity among brain regions remain poorly understood. Therefore, in this study, we recorded astrocyte intracellular calcium (Ca2+) concentrations of mice during sleep/wakefulness states in the cortex, hippocampus, hypothalamus, cerebellum, and pons using fiber photometry. For this purpose, male transgenic mice expressing the genetically encoded ratiometric Ca2+ sensor YCnano50 specifically in their astrocytes were used. We demonstrated that Ca2+ levels in astrocytes substantially decrease during rapid eye movement (REM) sleep, and increase after the onset of wakefulness. In contrast, differences in Ca2+ levels during non-REM (NREM) sleep were observed among the different brain regions, and no significant decrease was observed in the hypothalamus and pons. Further analyses focusing on the transition between sleep/wakefulness states and correlation analysis with the duration of REM sleep showed that Ca2+ dynamics differs among brain regions, suggesting the existence of several clusters, i.e., the first comprising the cortex and hippocampus, the second comprising the hypothalamus and pons, and the third comprising the cerebellum. Our study thus demonstrated that astrocyte Ca2+ levels change substantially according to sleep/wakefulness states. These changes were consistent in general unlike neural activity. However, we also clarified that Ca2+ dynamics varies depending on the brain region, implying that astrocytes may play various physiological roles in sleep.SIGNIFICANCE STATEMENT Sleep is an instinctive behavior of many organisms. In the previous five decades, the mechanism of the neural circuits controlling sleep/wakefulness states and the neural activities associated with sleep/wakefulness states in various brain regions have been elucidated. However, whether astrocytes, which are a type of glial cell, change their activity during different sleep/wakefulness states was poorly understood. Here, we demonstrated that dynamic changes in astrocyte Ca2+ concentrations occur in the cortex, hippocampus, hypothalamus, cerebellum, and pons of mice during natural sleep. Further analyses demonstrated that Ca2+ dynamics slightly differ among different brain regions, implying that the physiological roles of astrocytes in sleep/wakefulness might vary depending on the brain region.
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Affiliation(s)
- Tomomi Tsunematsu
- Super-network Brain Physiology, Graduate School of Life Sciences, Tohoku University, Sendai 980-8577, Japan
- Advanced Interdisciplinary Research Division, Frontier Research Institute for Interdisciplinary Sciences, Tohoku University, Sendai 980-8578, Japan
- Precursory Research for Embryonic Science and Technology, Japan Science and Technology Agency, Kawaguchi 332-0012, Japan
| | - Shuzo Sakata
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow G4 0RE, United Kingdom
| | - Tomomi Sanagi
- Advanced Interdisciplinary Research Division, Frontier Research Institute for Interdisciplinary Sciences, Tohoku University, Sendai 980-8578, Japan
| | - Kenji F Tanaka
- Department of Neuropsychiatry, Keio University School of Medicine, Tokyo 160-8582, Japan
| | - Ko Matsui
- Super-network Brain Physiology, Graduate School of Life Sciences, Tohoku University, Sendai 980-8577, Japan
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Rodríguez-Arzate CA, Martínez-Mendoza ML, Rocha-Mendoza I, Luna-Palacios Y, Licea-Rodríguez J, Martínez-Torres A. Morphological and Calcium Signaling Alterations of Neuroglial Cells in Cerebellar Cortical Dysplasia Induced by Carmustine. Cells 2021; 10:cells10071581. [PMID: 34201497 PMCID: PMC8304447 DOI: 10.3390/cells10071581] [Citation(s) in RCA: 3] [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] [Received: 03/23/2021] [Revised: 06/15/2021] [Accepted: 06/17/2021] [Indexed: 02/07/2023] Open
Abstract
Cortical dysplasias are alterations in the organization of the layers of the brain cortex due to problems in neuronal migration during development. The neuronal component has been widely studied in experimental models of cortical dysplasias. In contrast, little is known about how glia are affected. In the cerebellum, Bergmann glia (BG) are essential for neuronal migration during development, and in adult they mediate the control of fine movements through glutamatergic transmission. The aim of this study was to characterize the morphology and intracellular calcium dynamics of BG and astrocytes from mouse cerebellum and their modifications in a model of cortical dysplasia induced by carmustine (BCNU). Carmustine-treated mice were affected in their motor coordination and balance. Cerebellar dysplasias and heterotopias were more frequently found in lobule X. Morphology of BG cells and astrocytes was affected, as were their spontaneous [Ca2+]i transients in slice preparation and in vitro.
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Affiliation(s)
- Cynthia Alejandra Rodríguez-Arzate
- Instituto de Neurobiología (INB), Universidad Nacional Autónoma de México (UNAM), Campus Juriquilla, Querétaro 76230, QT, Mexico; (C.A.R.-A.); (M.L.M.-M.)
| | - Marianne Lizeth Martínez-Mendoza
- Instituto de Neurobiología (INB), Universidad Nacional Autónoma de México (UNAM), Campus Juriquilla, Querétaro 76230, QT, Mexico; (C.A.R.-A.); (M.L.M.-M.)
| | - Israel Rocha-Mendoza
- Centro de Investigación Científica y de Educación Superior de Ensenada (CICESE), Carretera Ensenada-Tijuana, No. 3918, Zona Playitas, Ensenada 22860, BC, Mexico; (I.R.-M.); (Y.L.-P.); (J.L.-R.)
| | - Yryx Luna-Palacios
- Centro de Investigación Científica y de Educación Superior de Ensenada (CICESE), Carretera Ensenada-Tijuana, No. 3918, Zona Playitas, Ensenada 22860, BC, Mexico; (I.R.-M.); (Y.L.-P.); (J.L.-R.)
| | - Jacob Licea-Rodríguez
- Centro de Investigación Científica y de Educación Superior de Ensenada (CICESE), Carretera Ensenada-Tijuana, No. 3918, Zona Playitas, Ensenada 22860, BC, Mexico; (I.R.-M.); (Y.L.-P.); (J.L.-R.)
- Cátedras CONACYT, Centro de Investigación Científica y de Educación Superior de Ensenada (CICESE), Ensenada 22860, BC, Mexico
| | - Ataúlfo Martínez-Torres
- Instituto de Neurobiología (INB), Universidad Nacional Autónoma de México (UNAM), Campus Juriquilla, Querétaro 76230, QT, Mexico; (C.A.R.-A.); (M.L.M.-M.)
- Correspondence:
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Lim EY, Ye L, Paukert M. Potential and Realized Impact of Astroglia Ca 2 + Dynamics on Circuit Function and Behavior. Front Cell Neurosci 2021; 15:682888. [PMID: 34163330 PMCID: PMC8215280 DOI: 10.3389/fncel.2021.682888] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Accepted: 05/03/2021] [Indexed: 11/13/2022] Open
Abstract
Astroglia display a wide range of spontaneous and behavioral state-dependent Ca2+ dynamics. During heightened vigilance, noradrenergic signaling leads to quasi-synchronous Ca2+ elevations encompassing soma and processes across the brain-wide astroglia network. Distinct from this vigilance-associated global Ca2+ rise are apparently spontaneous fluctuations within spatially restricted microdomains. Over the years, several strategies have been pursued to shed light on the physiological impact of these signals including deletion of endogenous ion channels or receptors and reduction of intracellular Ca2+ through buffering, extrusion or inhibition of release. Some experiments that revealed the most compelling behavioral alterations employed chemogenetic and optogenetic manipulations to modify astroglia Ca2+ signaling. However, there is considerable contrast between these findings and the comparatively modest effects of inhibiting endogenous sources of Ca2+. In this review, we describe the underlying mechanisms of various forms of astroglia Ca2+ signaling as well as the functional consequences of their inhibition. We then discuss how the effects of exogenous astroglia Ca2+ modification combined with our knowledge of physiological mechanisms of astroglia Ca2+ activation could guide further refinement of behavioral paradigms that will help elucidate the natural Ca2+-dependent function of astroglia.
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Affiliation(s)
- Eunice Y. Lim
- Department of Cellular and Integrative Physiology, University of Texas Health Science Center at San Antonio, San Antonio, TX, United States,Center for Biomedical Neuroscience, University of Texas Health Science Center at San Antonio, San Antonio, TX, United States
| | - Liang Ye
- Department of Cellular and Integrative Physiology, University of Texas Health Science Center at San Antonio, San Antonio, TX, United States
| | - Martin Paukert
- Department of Cellular and Integrative Physiology, University of Texas Health Science Center at San Antonio, San Antonio, TX, United States,Center for Biomedical Neuroscience, University of Texas Health Science Center at San Antonio, San Antonio, TX, United States,*Correspondence: Martin Paukert,
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42
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Yu X, Moye SL, Khakh BS. Local and CNS-Wide Astrocyte Intracellular Calcium Signaling Attenuation In Vivo with CalEx flox Mice. J Neurosci 2021; 41:4556-4574. [PMID: 33903221 PMCID: PMC8260243 DOI: 10.1523/jneurosci.0085-21.2021] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Revised: 03/21/2021] [Accepted: 03/30/2021] [Indexed: 01/12/2023] Open
Abstract
Astrocytes exist throughout the CNS and affect neural circuits and behavior through intracellular Ca2+ signaling. Studying the function(s) of astrocyte Ca2+ signaling has proven difficult because of the paucity of tools to achieve selective attenuation. Based on recent studies, we generated and used male and female knock-in mice for Cre-dependent expression of mCherry-tagged hPMCA2w/b to attenuate astrocyte Ca2+ signaling in genetically defined cells in vivo (CalExflox mice for Calcium Extrusion). We characterized CalExflox mice following local AAV-Cre microinjections into the striatum and found reduced astrocyte Ca2+ signaling (∼90%) accompanied with repetitive self-grooming behavior. We also crossed CalExflox mice to astrocyte-specific Aldh1l1-Cre/ERT2 mice to achieve inducible global CNS-wide Ca2+ signaling attenuation. Within 6 d of induction in the bigenic mice, we observed significantly altered ambulation in the open field, disrupted motor coordination and gait, and premature lethality. Furthermore, with histologic, imaging, and transcriptomic analyses, we identified cellular and molecular alterations in the cerebellum following mCherry-tagged hPMCA2w/b expression. Our data show that expression of mCherry-tagged hPMCA2w/b with CalExflox mice throughout the CNS resulted in substantial attenuation of astrocyte Ca2+ signaling and significant behavioral alterations in adult mice. We interpreted these findings candidly in relation to the ability of CalEx to attenuate astrocyte Ca2+ signaling, with regards to additional mechanistic interpretations of the data, and their relation to past studies that reduced astrocyte Ca2+ signaling throughout the CNS. The data and resources provide complementary ways to interrogate the function(s) of astrocytes in multiple experimental scenarios.SIGNIFICANCE STATEMENT Astrocytes represent a significant fraction of all brain cells and tile the entire central nervous system. Unlike neurons, astrocytes lack propagated electrical signals. Instead, astrocytes are proposed to use diverse and dynamic intracellular Ca2+ signals to communicate with other cells. An open question concerns if and how astrocyte Ca2+ signaling regulates behavior in adult mice. We approached this problem by generating a new transgenic mouse line to achieve inducible astrocyte Ca2+ signaling attenuation in vivo We report our data with this mouse line and we interpret the findings candidly in relation to past studies and within the framework of different mechanistic interpretations.
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Affiliation(s)
- Xinzhu Yu
- Department of Physiology
- Department of Molecular and Integrative Physiology, Beckman Institute, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801-3704
| | | | - Baljit S Khakh
- Department of Physiology
- Department of Neurobiology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California 90095-1751
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43
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Lim D, Semyanov A, Genazzani A, Verkhratsky A. Calcium signaling in neuroglia. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2021; 362:1-53. [PMID: 34253292 DOI: 10.1016/bs.ircmb.2021.01.003] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Glial cells exploit calcium (Ca2+) signals to perceive the information about the activity of the nervous tissue and the tissue environment to translate this information into an array of homeostatic, signaling and defensive reactions. Astrocytes, the best studied glial cells, use several Ca2+ signaling generation pathways that include Ca2+ entry through plasma membrane, release from endoplasmic reticulum (ER) and from mitochondria. Activation of metabotropic receptors on the plasma membrane of glial cells is coupled to an enzymatic cascade in which a second messenger, InsP3 is generated thus activating intracellular Ca2+ release channels in the ER endomembrane. Astrocytes also possess store-operated Ca2+ entry and express several ligand-gated Ca2+ channels. In vivo astrocytes generate heterogeneous Ca2+ signals, which are short and frequent in distal processes, but large and relatively rare in soma. In response to neuronal activity intracellular and inter-cellular astrocytic Ca2+ waves can be produced. Astrocytic Ca2+ signals are involved in secretion, they regulate ion transport across cell membranes, and are contributing to cell morphological plasticity. Therefore, astrocytic Ca2+ signals are linked to fundamental functions of the central nervous system ranging from synaptic transmission to behavior. In oligodendrocytes, Ca2+ signals are generated by plasmalemmal Ca2+ influx, or by release from intracellular stores, or by combination of both. Microglial cells exploit Ca2+ permeable ionotropic purinergic receptors and transient receptor potential channels as well as ER Ca2+ release. In this contribution, basic morphology of glial cells, glial Ca2+ signaling toolkit, intracellular Ca2+ signals and Ca2+-regulated functions are discussed with focus on astrocytes.
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Affiliation(s)
- Dmitry Lim
- Department of Pharmaceutical Sciences, Università del Piemonte Orientale, Novara, Italy.
| | - Alexey Semyanov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia; Faculty of Biology, Moscow State University, Moscow, Russia; Sechenov First Moscow State Medical University, Moscow, Russia
| | - Armando Genazzani
- Department of Pharmaceutical Sciences, Università del Piemonte Orientale, Novara, Italy
| | - Alexei Verkhratsky
- Sechenov First Moscow State Medical University, Moscow, Russia; Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom; Achucarro Centre for Neuroscience, IKERBASQUE, Basque Foundation for Science, Bilbao, Spain.
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Vaidyanathan TV, Collard M, Yokoyama S, Reitman ME, Poskanzer KE. Cortical astrocytes independently regulate sleep depth and duration via separate GPCR pathways. eLife 2021; 10:63329. [PMID: 33729913 PMCID: PMC7968927 DOI: 10.7554/elife.63329] [Citation(s) in RCA: 65] [Impact Index Per Article: 21.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Accepted: 02/17/2021] [Indexed: 12/11/2022] Open
Abstract
Non-rapid eye movement (NREM) sleep, characterized by slow-wave electrophysiological activity, underlies several critical functions, including learning and memory. However, NREM sleep is heterogeneous, varying in duration, depth, and spatially across the cortex. While these NREM sleep features are thought to be largely independently regulated, there is also evidence that they are mechanistically coupled. To investigate how cortical NREM sleep features are controlled, we examined the astrocytic network, comprising a cortex-wide syncytium that influences population-level neuronal activity. We quantified endogenous astrocyte activity in mice over natural sleep and wake, then manipulated specific astrocytic G-protein-coupled receptor (GPCR) signaling pathways in vivo. We find that astrocytic Gi- and Gq-coupled GPCR signaling separately control NREM sleep depth and duration, respectively, and that astrocytic signaling causes differential changes in local and remote cortex. These data support a model in which the cortical astrocyte network serves as a hub for regulating distinct NREM sleep features. Sleep has many roles, from strengthening new memories to regulating mood and appetite. While we might instinctively think of sleep as a uniform state of reduced brain activity, the reality is more complex. First, over the course of the night, we cycle between a number of different sleep stages, which reflect different levels of sleep depth. Second, the amount of sleep depth is not necessarily even across the brain but can vary between regions. These sleep stages consist of either rapid eye movement (REM) sleep or non-REM (NREM) sleep. REM sleep is when most dreaming occurs, whereas NREM sleep is particularly important for learning and memory and can vary in duration and depth. During NREM sleep, large groups of neurons synchronize their firing to create rhythmic waves of activity known as slow waves. The more synchronous the activity, the deeper the sleep. Vaidyanathan et al. now show that brain cells called astrocytes help regulate NREM sleep. Astrocytes are not neurons but belong to a group of specialized cells called glia. They are the largest glia cell type in the brain and display an array of proteins on their surfaces called G-protein-coupled receptors (GPCRs). These enable them to sense sleep-wake signals from other parts of the brain and to generate their own signals. In fact, each astrocyte can communicate with thousands of neurons at once. They are therefore well-poised to coordinate brain activity during NREM sleep. Using innovative tools, Vaidyanathan et al. visualized astrocyte activity in mice as the animals woke up or fell asleep. The results showed that astrocytes change their activity just before each sleep–wake transition. They also revealed that astrocytes control both the depth and duration of NREM sleep via two different types of GPCR signals. Increasing one of these signals (Gi-GPCR) made the mice sleep more deeply but did not change sleep duration. Decreasing the other (Gq-GPCR) made the mice sleep for longer but did not affect sleep depth. Sleep problems affect many people at some point in their lives, and often co-exist with other conditions such as mental health disorders. Understanding how the brain regulates different features of sleep could help us develop better – and perhaps more specific – treatments for sleep disorders. The current study suggests that manipulating GPCRs on astrocytes might increase sleep depth, for example. But before work to test this idea can begin, we must first determine whether findings from sleeping mice also apply to people.
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Affiliation(s)
- Trisha V Vaidyanathan
- Neuroscience Graduate Program, University of California, San Francisco, San Francisco, United States.,Department of Biochemistry & Biophysics, University of California, San Francisco, San Francisco, United States
| | - Max Collard
- Neuroscience Graduate Program, University of California, San Francisco, San Francisco, United States
| | - Sae Yokoyama
- Department of Biochemistry & Biophysics, University of California, San Francisco, San Francisco, United States
| | - Michael E Reitman
- Neuroscience Graduate Program, University of California, San Francisco, San Francisco, United States.,Department of Biochemistry & Biophysics, University of California, San Francisco, San Francisco, United States
| | - Kira E Poskanzer
- Neuroscience Graduate Program, University of California, San Francisco, San Francisco, United States.,Department of Biochemistry & Biophysics, University of California, San Francisco, San Francisco, United States.,Kavli Institute for Fundamental Neuroscience, San Francisco, United States
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45
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Huntington TE, Srinivasan R. Astrocytic mitochondria in adult mouse brain slices show spontaneous calcium influx events with unique properties. Cell Calcium 2021; 96:102383. [PMID: 33676316 DOI: 10.1016/j.ceca.2021.102383] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Revised: 02/07/2021] [Accepted: 02/21/2021] [Indexed: 12/17/2022]
Abstract
Astrocytes govern critical aspects of brain function via spontaneous calcium signals in their soma and processes. A significant proportion of these spontaneous astrocytic calcium events are associated with mitochondria, however, the extent, sources, or kinetics of astrocytic mitochondrial calcium influx have not been studied in the adult mouse brain. To measure calcium influx into astrocytic mitochondria in situ, we generated an adeno-associated virus (AAV) with the astrocyte-specific GfaABC1D promoter driving expression of the genetically encoded calcium indicator, GCaMP6f tagged to mito7, a mitochondrial matrix targeted signal sequence. Using this construct, we observed AAV-mediated expression of GCaMP6f in adult mouse astrocytic mitochondria that co-localized with MitoTracker deep red (MTDR) in the dorsolateral striatum (DLS) and in the hippocampal stratum radiatum (HPC). Astrocytic mitochondria co-labeled with MTDR and GCaMP6f displayed robust, spontaneous calcium influx events in situ, with subcellular differences in calcium influx kinetics between somatic, branch, and branchlet mitochondria, and inter-regional differences between mitochondria in DLS and HPC astrocytes. Calcium influx into astrocytic mitochondria was strongly dependent on endoplasmic reticulum calcium stores, but did not require the mitochondrial calcium uniporter, MCU. Exposure to either glutamate, D1 or D2 dopamine receptor agonists increased calcium influx in some mitochondria, while simultaneously decreasing calcium influx in other mitochondria from the same astrocyte. These findings show that astrocytic mitochondria possess unique properties with regard to their subcellular morphology, mechanisms of calcium influx, and responses to neurotransmitter receptor agonists. Our results have important implications for understanding the role of astrocytic mitochondria during pathological processes.
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Affiliation(s)
- Taylor E Huntington
- Department of Neuroscience & Experimental Therapeutics, Texas A&M College of Medicine, Bryan, TX 77807, USA; Texas A&M Institute for Neuroscience (TAMIN), Texas A&M University, College Station, TX 77843, USA
| | - Rahul Srinivasan
- Department of Neuroscience & Experimental Therapeutics, Texas A&M College of Medicine, Bryan, TX 77807, USA; Texas A&M Institute for Neuroscience (TAMIN), Texas A&M University, College Station, TX 77843, USA.
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46
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Sharma K, Gordon GRJ, Tran CHT. Heterogeneity of Sensory-Induced Astrocytic Ca 2+ Dynamics During Functional Hyperemia. Front Physiol 2020; 11:611884. [PMID: 33362585 PMCID: PMC7758506 DOI: 10.3389/fphys.2020.611884] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Accepted: 11/24/2020] [Indexed: 12/17/2022] Open
Abstract
Astrocytic Ca2+ fluctuations associated with functional hyperemia have typically been measured from large cellular compartments such as the soma, the whole arbor and the endfoot. The most prominent Ca2+ event is a large magnitude, delayed signal that follows vasodilation. However, previous work has provided little information about the spatio-temporal properties of such Ca2+ transients or their heterogeneity. Here, using an awake, in vivo two-photon fluorescence-imaging model, we performed detailed profiling of delayed astrocytic Ca2+ signals across astrocytes or within individual astrocyte compartments using small regions of interest next to penetrating arterioles and capillaries along with vasomotor responses to vibrissae stimulation. We demonstrated that while a 5-s air puff that stimulates all whiskers predominantly generated reproducible functional hyperemia in the presence or absence of astrocytic Ca2+ changes, whisker stimulation inconsistently produced astrocytic Ca2+ responses. More importantly, these Ca2+ responses were heterogeneous among subcellular structures of the astrocyte and across different astrocytes that resided within the same field of view. Furthermore, we found that whisker stimulation induced discrete Ca2+ “hot spots” that spread regionally within the endfoot. These data reveal that astrocytic Ca2+ dynamics associated with the microvasculature are more complex than previously thought, and highlight the importance of considering the heterogeneity of astrocytic Ca2+ activity to fully understanding neurovascular coupling.
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Affiliation(s)
- Kushal Sharma
- Department of Physiology and Cell Biology, Center for Molecular and Cellular Signaling in the Cardiovascular System, University of Nevada, Reno School of Medicine, Reno, NV, United States
| | - Grant R J Gordon
- Department of Physiology and Pharmacology, School of Medicine, Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada
| | - Cam Ha T Tran
- Department of Physiology and Cell Biology, Center for Molecular and Cellular Signaling in the Cardiovascular System, University of Nevada, Reno School of Medicine, Reno, NV, United States
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47
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Qin H, He W, Yang C, Li J, Jian T, Liang S, Chen T, Feng H, Chen X, Liao X, Zhang K. Monitoring Astrocytic Ca 2+ Activity in Freely Behaving Mice. Front Cell Neurosci 2020; 14:603095. [PMID: 33343304 PMCID: PMC7744696 DOI: 10.3389/fncel.2020.603095] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2020] [Accepted: 11/09/2020] [Indexed: 12/24/2022] Open
Abstract
Monitoring astrocytic Ca2+ activity is essential to understand the physiological and pathological roles of astrocytes in the brain. However, previous commonly used methods for studying astrocytic Ca2+ activities can be applied in only anesthetized or head-fixed animals, which significantly affects in vivo astrocytic Ca2+ dynamics. In the current study, we combined optic fiber recordings with genetically encoded Ca2+ indicators (GECIs) to monitor astrocytic activity in freely behaving mice. This approach enabled selective and reliable measurement of astrocytic Ca2+ activity, which was verified by the astrocyte-specific labeling of GECIs and few movement artifacts. Additionally, astrocytic Ca2+ activities induced by locomotion or footshock were stably recorded in the cortices and hippocampi of freely behaving mice. Furthermore, this method allowed for the longitudinal study of astrocytic activities over several weeks. This work provides a powerful approach to record astrocytic activity selectively, stably, and chronically in freely behaving mice.
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Affiliation(s)
- Han Qin
- Brain Research Center and State Key Laboratory of Trauma, Burns, and Combined Injury, Third Military Medical University, Chongqing, China.,Center for Neurointelligence, School of Medicine, Chongqing University, Chongqing, China
| | - Wenjing He
- Brain Research Center and State Key Laboratory of Trauma, Burns, and Combined Injury, Third Military Medical University, Chongqing, China
| | - Chuanyan Yang
- Department of Neurosurgery and Key Laboratory of Neurotrauma, Southwest Hospital, Third Military Medical University, Chongqing, China
| | - Jin Li
- Brain Research Center and State Key Laboratory of Trauma, Burns, and Combined Injury, Third Military Medical University, Chongqing, China
| | - Tingliang Jian
- Brain Research Center and State Key Laboratory of Trauma, Burns, and Combined Injury, Third Military Medical University, Chongqing, China
| | - Shanshan Liang
- Brain Research Center and State Key Laboratory of Trauma, Burns, and Combined Injury, Third Military Medical University, Chongqing, China
| | - Tunan Chen
- Department of Neurosurgery and Key Laboratory of Neurotrauma, Southwest Hospital, Third Military Medical University, Chongqing, China
| | - Hua Feng
- Department of Neurosurgery and Key Laboratory of Neurotrauma, Southwest Hospital, Third Military Medical University, Chongqing, China
| | - Xiaowei Chen
- Brain Research Center and State Key Laboratory of Trauma, Burns, and Combined Injury, Third Military Medical University, Chongqing, China
| | - Xiang Liao
- Center for Neurointelligence, School of Medicine, Chongqing University, Chongqing, China
| | - Kuan Zhang
- Brain Research Center and State Key Laboratory of Trauma, Burns, and Combined Injury, Third Military Medical University, Chongqing, China
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48
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Lago-Baldaia I, Fernandes VM, Ackerman SD. More Than Mortar: Glia as Architects of Nervous System Development and Disease. Front Cell Dev Biol 2020; 8:611269. [PMID: 33381506 PMCID: PMC7767919 DOI: 10.3389/fcell.2020.611269] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Accepted: 11/17/2020] [Indexed: 12/12/2022] Open
Abstract
Glial cells are an essential component of the nervous system of vertebrates and invertebrates. In the human brain, glia are as numerous as neurons, yet the importance of glia to nearly every aspect of nervous system development has only been expounded over the last several decades. Glia are now known to regulate neural specification, synaptogenesis, synapse function, and even broad circuit function. Given their ubiquity, it is not surprising that the contribution of glia to neuronal disease pathogenesis is a growing area of research. In this review, we will summarize the accumulated evidence of glial participation in several distinct phases of nervous system development and organization-neural specification, circuit wiring, and circuit function. Finally, we will highlight how these early developmental roles of glia contribute to nervous system dysfunction in neurodevelopmental and neurodegenerative disorders.
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Affiliation(s)
- Inês Lago-Baldaia
- Department of Cell and Developmental Biology, University College London, London, United Kingdom
| | - Vilaiwan M. Fernandes
- Department of Cell and Developmental Biology, University College London, London, United Kingdom
| | - Sarah D. Ackerman
- Institute of Neuroscience, Howard Hughes Medical Institute, University of Oregon, Eugene, OR, United States
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49
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Bergel A, Tiran E, Deffieux T, Demené C, Tanter M, Cohen I. Adaptive modulation of brain hemodynamics across stereotyped running episodes. Nat Commun 2020; 11:6193. [PMID: 33273463 PMCID: PMC7713412 DOI: 10.1038/s41467-020-19948-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Accepted: 11/06/2020] [Indexed: 12/14/2022] Open
Abstract
During locomotion, theta and gamma rhythms are essential to ensure timely communication between brain structures. However, their metabolic cost and contribution to neuroimaging signals remain elusive. To finely characterize neurovascular interactions during locomotion, we simultaneously recorded mesoscale brain hemodynamics using functional ultrasound (fUS) and local field potentials (LFP) in numerous brain structures of freely-running overtrained rats. Locomotion events were reliably followed by a surge in blood flow in a sequence involving the retrosplenial cortex, dorsal thalamus, dentate gyrus and CA regions successively, with delays ranging from 0.8 to 1.6 seconds after peak speed. Conversely, primary motor cortex was suppressed and subsequently recruited during reward uptake. Surprisingly, brain hemodynamics were strongly modulated across trials within the same recording session; cortical blood flow sharply decreased after 10-20 runs, while hippocampal responses strongly and linearly increased, particularly in the CA regions. This effect occurred while running speed and theta activity remained constant and was accompanied by an increase in the power of hippocampal, but not cortical, high-frequency oscillations (100-150 Hz). Our findings reveal distinct vascular subnetworks modulated across fast and slow timescales and suggest strong hemodynamic adaptation, despite the repetition of a stereotyped behavior.
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Affiliation(s)
- Antoine Bergel
- Sorbonne Université, CNRS, INSERM, Institut de Biologie Paris Seine-Neuroscience, 75005, Paris, France.
- Physique pour la Médecine Paris, INSERM U1273, ESPCI Paris, CNRS FRE 2031, PSL Université Recherche, Paris, France.
| | - Elodie Tiran
- Physique pour la Médecine Paris, INSERM U1273, ESPCI Paris, CNRS FRE 2031, PSL Université Recherche, Paris, France
| | - Thomas Deffieux
- Physique pour la Médecine Paris, INSERM U1273, ESPCI Paris, CNRS FRE 2031, PSL Université Recherche, Paris, France
| | - Charlie Demené
- Physique pour la Médecine Paris, INSERM U1273, ESPCI Paris, CNRS FRE 2031, PSL Université Recherche, Paris, France
| | - Mickaël Tanter
- Physique pour la Médecine Paris, INSERM U1273, ESPCI Paris, CNRS FRE 2031, PSL Université Recherche, Paris, France.
| | - Ivan Cohen
- Sorbonne Université, CNRS, INSERM, Institut de Biologie Paris Seine-Neuroscience, 75005, Paris, France.
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50
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Ye L, Orynbayev M, Zhu X, Lim EY, Dereddi RR, Agarwal A, Bergles DE, Bhat MA, Paukert M. Ethanol abolishes vigilance-dependent astroglia network activation in mice by inhibiting norepinephrine release. Nat Commun 2020; 11:6157. [PMID: 33268792 PMCID: PMC7710743 DOI: 10.1038/s41467-020-19475-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Accepted: 10/16/2020] [Indexed: 12/17/2022] Open
Abstract
Norepinephrine adjusts sensory processing in cortical networks and gates plasticity enabling adaptive behavior. The actions of norepinephrine are profoundly altered by recreational drugs like ethanol, but the consequences of these changes on distinct targets such as astrocytes, which exhibit norepinephrine-dependent Ca2+ elevations during vigilance, are not well understood. Using in vivo two-photon imaging, we show that locomotion-induced Ca2+ elevations in mouse astroglia are profoundly inhibited by ethanol, an effect that can be reversed by enhancing norepinephrine release. Vigilance-dependent astroglial activation is abolished by deletion of α1A-adrenergic receptor from astroglia, indicating that norepinephrine acts directly on these ubiquitous glial cells. Ethanol reduces vigilance-dependent Ca2+ transients in noradrenergic terminals, but has little effect on astroglial responsiveness to norepinephrine, suggesting that ethanol suppresses their activation by inhibiting norepinephrine release. Since abolition of astroglia Ca2+ activation does not affect motor coordination, global suppression of astroglial networks may contribute to the cognitive effects of alcohol intoxication. The effects of norepinephrine on sensory processing in cortical networks are altered by recreational drugs like ethanol. The authors show that ethanol suppresses the activation of astrocytes by inhibiting norepinephrine release which may contribute to the cognitive effects of alcohol intoxication.
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Affiliation(s)
- Liang Ye
- Department of Cellular and Integrative Physiology, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA
| | - Murat Orynbayev
- Department of Cellular and Integrative Physiology, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA
| | - Xiangyu Zhu
- Department of Cellular and Integrative Physiology, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA.,Xiangya School of Medicine, Central South University, Changsha, Hunan, China
| | - Eunice Y Lim
- Department of Cellular and Integrative Physiology, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA.,Center for Biomedical Neuroscience, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA
| | - Ram R Dereddi
- The Chica and Heinz Schaller Research Group, Institute for Anatomy and Cell Biology, Heidelberg University, Heidelberg, Germany
| | - Amit Agarwal
- The Chica and Heinz Schaller Research Group, Institute for Anatomy and Cell Biology, Heidelberg University, Heidelberg, Germany.,Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Dwight E Bergles
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, USA.,Johns Hopkins Kavli Neuroscience Discovery Institute, Baltimore, MD, USA
| | - Manzoor A Bhat
- Department of Cellular and Integrative Physiology, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA.,Center for Biomedical Neuroscience, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA
| | - Martin Paukert
- Department of Cellular and Integrative Physiology, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA. .,Center for Biomedical Neuroscience, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA.
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