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Aramideh JA, Vidal-Itriago A, Morsch M, Graeber MB. Cytokine Signalling at the Microglial Penta-Partite Synapse. Int J Mol Sci 2021; 22:ijms222413186. [PMID: 34947983 PMCID: PMC8708012 DOI: 10.3390/ijms222413186] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2021] [Revised: 12/01/2021] [Accepted: 12/02/2021] [Indexed: 12/28/2022] Open
Abstract
Microglial cell processes form part of a subset of synaptic contacts that have been dubbed microglial tetra-partite or quad-partite synapses. Since tetrapartite may also refer to the presence of extracellular matrix components, we propose the more precise term microglial penta-partite synapse for synapses that show a microglial cell process in close physical proximity to neuronal and astrocytic synaptic constituents. Microglial cells are now recognised as key players in central nervous system (CNS) synaptic changes. When synaptic plasticity involving microglial penta-partite synapses occurs, microglia may utilise their cytokine arsenal to facilitate the generation of new synapses, eliminate those that are not needed anymore, or modify the molecular and structural properties of the remaining synaptic contacts. In addition, microglia–synapse contacts may develop de novo under pathological conditions. Microglial penta-partite synapses have received comparatively little attention as unique sites in the CNS where microglial cells, cytokines and other factors they release have a direct influence on the connections between neurons and their function. It concerns our understanding of the penta-partite synapse where the confusion created by the term “neuroinflammation” is most counterproductive. The mere presence of activated microglia or the release of their cytokines may occur independent of inflammation, and penta-partite synapses are not usually active in a neuroimmunological sense. Clarification of these details is the main purpose of this review, specifically highlighting the relationship between microglia, synapses, and the cytokines that can be released by microglial cells in health and disease.
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Affiliation(s)
- Jason Abbas Aramideh
- Brain and Mind Centre, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW 2006, Australia;
| | - Andres Vidal-Itriago
- Faculty of Medicine, Health & Human Sciences, Macquarie Medical School, Macquarie University, Sydney, NSW 2109, Australia; (A.V.-I.); (M.M.)
| | - Marco Morsch
- Faculty of Medicine, Health & Human Sciences, Macquarie Medical School, Macquarie University, Sydney, NSW 2109, Australia; (A.V.-I.); (M.M.)
| | - Manuel B. Graeber
- Brain and Mind Centre, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW 2006, Australia;
- Correspondence:
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Kiaee K, Jodat YA, Bassous NJ, Matharu N, Shin SR. Transcriptomic Mapping of Neural Diversity, Differentiation and Functional Trajectory in iPSC-Derived 3D Brain Organoid Models. Cells 2021; 10:3422. [PMID: 34943930 PMCID: PMC8700452 DOI: 10.3390/cells10123422] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Revised: 11/26/2021] [Accepted: 11/27/2021] [Indexed: 11/17/2022] Open
Abstract
Experimental models of the central nervous system (CNS) are imperative for developmental and pathophysiological studies of neurological diseases. Among these models, three-dimensional (3D) induced pluripotent stem cell (iPSC)-derived brain organoid models have been successful in mitigating some of the drawbacks of 2D models; however, they are plagued by high organoid-to-organoid variability, making it difficult to compare specific gene regulatory pathways across 3D organoids with those of the native brain. Single-cell RNA sequencing (scRNA-seq) transcriptome datasets have recently emerged as powerful tools to perform integrative analyses and compare variability across organoids. However, transcriptome studies focusing on late-stage neural functionality development have been underexplored. Here, we combine and analyze 8 brain organoid transcriptome databases to study the correlation between differentiation protocols and their resulting cellular functionality across various 3D organoid and exogenous brain models. We utilize dimensionality reduction methods including principal component analysis (PCA) and uniform manifold approximation projection (UMAP) to identify and visualize cellular diversity among 3D models and subsequently use gene set enrichment analysis (GSEA) and developmental trajectory inference to quantify neuronal behaviors such as axon guidance, synapse transmission and action potential. We showed high similarity in cellular composition, cellular differentiation pathways and expression of functional genes in human brain organoids during induction and differentiation phases, i.e., up to 3 months in culture. However, during the maturation phase, i.e., 6-month timepoint, we observed significant developmental deficits and depletion of neuronal and astrocytes functional genes as indicated by our GSEA results. Our results caution against use of organoids to model pathophysiology and drug response at this advanced time point and provide insights to tune in vitro iPSC differentiation protocols to achieve desired neuronal functionality and improve current protocols.
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Affiliation(s)
- Kiavash Kiaee
- Division of Engineering in Medicine, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Cambridge, MA 02139, USA; (Y.A.J.); (N.J.B.)
- Department of Mechanical Engineering, Stevens Institute of Technology, Hoboken, NJ 07030, USA
| | - Yasamin A. Jodat
- Division of Engineering in Medicine, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Cambridge, MA 02139, USA; (Y.A.J.); (N.J.B.)
- Department of Mechanical Engineering, Stevens Institute of Technology, Hoboken, NJ 07030, USA
| | - Nicole J. Bassous
- Division of Engineering in Medicine, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Cambridge, MA 02139, USA; (Y.A.J.); (N.J.B.)
| | - Navneet Matharu
- Department of Bioengineering and Therapeutic Sciences, University of California San Francisco, San Francisco, CA 94143, USA;
- Institute for Human Genetics, University of California San Francisco, San Francisco, CA 94143, USA
- Innovative Genomics Institute, University of California San Francisco, San Francisco, CA 94720, USA
| | - Su Ryon Shin
- Division of Engineering in Medicine, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Cambridge, MA 02139, USA; (Y.A.J.); (N.J.B.)
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"Tripartite Synapses" in Taste Buds: A Role for Type I Glial-like Taste Cells. J Neurosci 2021; 41:9860-9871. [PMID: 34697094 DOI: 10.1523/jneurosci.1444-21.2021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Revised: 09/29/2021] [Accepted: 10/17/2021] [Indexed: 11/21/2022] Open
Abstract
In mammalian taste buds, Type I cells comprise half of all cells. These are termed "glial-like" based on morphologic and molecular features, but there are limited studies describing their function. We tested whether Type I cells sense chemosensory activation of adjacent chemosensory (i.e., Types II and III) taste bud cells, similar to synaptic glia. Using Gad2;;GCaMP3 mice of both sexes, we confirmed by immunostaining that, within taste buds, GCaMP expression is predominantly in Type I cells (with no Type II and ≈28% Type III cells expressing weakly). In dissociated taste buds, GCaMP+ Type I cells responded to bath-applied ATP (10-100 μm) but not to 5-HT (transmitters released by Type II or III cells, respectively). Type I cells also did not respond to taste stimuli (5 μm cycloheximide, 1 mm denatonium). In lingual slice preparations also, Type I cells responded to bath-applied ATP (10-100 μm). However, when taste buds in the slice were stimulated with bitter tastants (cycloheximide, denatonium, quinine), Type I cells responded robustly. Taste-evoked responses of Type I cells in the slice preparation were significantly reduced by desensitizing purinoceptors or by purinoceptor antagonists (suramin, PPADS), and were essentially eliminated by blocking synaptic ATP release (carbenoxolone) or degrading extracellular ATP (apyrase). Thus, taste-evoked release of afferent ATP from type II chemosensory cells, in addition to exciting gustatory afferent fibers, also activates glial-like Type I taste cells. We speculate that Type I cells sense chemosensory activation and that they participate in synaptic signaling, similarly to glial cells at CNS tripartite synapses.SIGNIFICANCE STATEMENT Most studies of taste buds view the chemosensitive excitable cells that express taste receptors as the sole mediators of taste detection and transmission to the CNS. Type I "glial-like" cells, with their ensheathing morphology, are mostly viewed as responsible for clearing neurotransmitters and as the "glue" holding the taste bud together. In the present study, we demonstrate that, when intact taste buds respond to their natural stimuli, Type I cells sense the activation of the chemosensory cells by detecting the afferent transmitter. Because Type I cells synthesize GABA, a known gliotransmitter, and cognate receptors are present on both presynaptic and postsynaptic elements, Type I cells may participate in GABAergic synaptic transmission in the manner of astrocytes at tripartite synapses.
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Han J, Yoon S, Park H. Endocytic BDNF secretion regulated by Vamp3 in astrocytes. Sci Rep 2021; 11:21203. [PMID: 34707216 PMCID: PMC8551197 DOI: 10.1038/s41598-021-00693-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2021] [Accepted: 10/15/2021] [Indexed: 11/26/2022] Open
Abstract
Brain-derived neurotrophic factor (BDNF) regulates diverse brain functions via TrkB receptor signaling. Due to the expression of TrkB receptors, astrocytes can internalize extracellular BDNF proteins via receptor-mediated endocytosis. Endocytosed BDNF can be re-secreted upon stimulation, but the molecular mechanism underlying this phenomenon remains unrecognized. Our study reveals that vesicle-associated membrane protein 3 (Vamp3) selectively regulates the release of endocytic BDNF from astrocytes. By using quantum dot (QD)-conjugated mature BDNF (QD-BDNF) as a proxy for the extracellular BDNF protein, we monitored the uptake, transport, and secretion of BDNF from cultured cortical astrocytes. Our data showed that endocytic QD-BDNF particles were enriched in Vamp3-containing vesicles in astrocytes and that ATP treatment sufficiently triggered either the antero- or retrograde transport and exocytosis of QD-BDNF-containing vesicles. Downregulation of Vamp3 expression disrupted endocytic BDNF secretion from astrocytes but did not affect uptake or transport. Collectively, these results provide evidence of the selective ability of astrocytic Vamp3 to control endocytic BDNF secretion during BDNF recycling.
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Affiliation(s)
- Jeongho Han
- Research Group of Neurovascular Unit, Korea Brain Research Institute (KBRI), Daegu, 41062, South Korea
| | - Sungryeong Yoon
- Department of Brain and Cognitive Sciences, DGIST, Daegu, 42988, South Korea
| | - Hyungju Park
- Research Group of Neurovascular Unit, Korea Brain Research Institute (KBRI), Daegu, 41062, South Korea. .,Department of Brain and Cognitive Sciences, DGIST, Daegu, 42988, South Korea.
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Blank N, Mayer M, Mass E. The development and physiological and pathophysiological functions of resident macrophages and glial cells. Adv Immunol 2021; 151:1-47. [PMID: 34656287 DOI: 10.1016/bs.ai.2021.08.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
In the past, brain function and the onset and progression of neurological diseases have been studied in a neuron-centric manner. However, in recent years the focus of many neuroscientists has shifted to other cell types that promote neurodevelopment and contribute to the functionality of neuronal networks in health and disease. Particularly microglia and astrocytes have been implicated in actively contributing to and controlling neuronal development, neuroinflammation, and neurodegeneration. Here, we summarize the development of brain-resident macrophages and astrocytes and their core functions in the developing brain. We discuss their contribution and intercellular crosstalk during tissue homeostasis and pathophysiology. We argue that in-depth knowledge of non-neuronal cells in the brain could provide novel therapeutic targets to reverse or contain neurological diseases.
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Affiliation(s)
- Nelli Blank
- Developmental Biology of the Immune System, Life & Medical Sciences (LIMES) Institute, University of Bonn, Bonn, Germany.
| | - Marina Mayer
- Developmental Biology of the Immune System, Life & Medical Sciences (LIMES) Institute, University of Bonn, Bonn, Germany
| | - Elvira Mass
- Developmental Biology of the Immune System, Life & Medical Sciences (LIMES) Institute, University of Bonn, Bonn, Germany.
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Li D, Li T, Yu J, Liu X, Jia S, Wang X, Wang P, Wang YF. Astrocytic Modulation of Supraoptic Oxytocin Neuronal Activity in Rat Dams with Pup-Deprivation at Different Stages of Lactation. Neurochem Res 2021; 46:2601-2611. [PMID: 32930948 DOI: 10.1007/s11064-020-03129-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 09/05/2020] [Accepted: 09/08/2020] [Indexed: 02/06/2023]
Abstract
Appropriate interactions between astrocytes and oxytocin neurons in the hypothalamo- neurohypophysial system are essential for normal lactation. To further explore the mechanisms underlying astrocytic modulation of oxytocin neuronal activity, we observed astrocytic plasticity in the supraoptic nucleus of lactating rats with intermittent pup-deprivation (PD, 20 h/day) at early (day 1-5) and middle (day 8-12) stages of lactation. PD at both stages decreased suckling duration and litter's body weight gain. They also significantly increased the expression of glial fibrillary acidic protein (GFAP) in Western blots while increased GFAP filaments and the colocalization of GFAP filaments with aquaporin 4 (AQP4) puncta in astrocyte processes surrounding oxytocin neuronal somata in immunohistochemistry in the supraoptic nucleus. Suckling between adjacent milk ejections but not shortly after them decreased molecular association between GFAP and AQP4. In hypothalamic slices from male rats, oxytocin treatment (0.1 nmol/L, 10 min) significantly reduced the length of GFAP filaments and AQP4 puncta in the processes but increased GFAP staining in the somata. These oxytocin effects were blocked by pretreatment of the slices with N-(1,3,4-Thiadiazolyl) nicotinamide (TGN-020, inhibitor of AQP4, 10 µmol/L, 5 min before oxytocin). In addition, inhibition of AQP4 with TGN-020 blocked excitation in oxytocin neurons evoked by prostaglandin E2, a downstream signal of oxytocin receptor and mediator of oxytocin-evoked burst firing, in whole-cell patch-clamp recordings. These results indicate that AQP4-associated astrocytic plasticity is essential for normal oxytocin neuronal activity during lactation and that PD-evoked hypogalactia is associated with astrocytic process expansion following increased GFAP and AQP4 expressions.
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Affiliation(s)
- Dongyang Li
- Department of Physiology, School of Basic Medical Sciences, Harbin Medical University, 157 Baojian Road, Nangang, Harbin, 150081, China
| | - Tong Li
- Department of Physiology, School of Basic Medical Sciences, Harbin Medical University, 157 Baojian Road, Nangang, Harbin, 150081, China
| | - Jiawei Yu
- Department of Physiology, School of Basic Medical Sciences, Harbin Medical University, 157 Baojian Road, Nangang, Harbin, 150081, China
| | - Xiaoyu Liu
- Department of Physiology, School of Basic Medical Sciences, Harbin Medical University, 157 Baojian Road, Nangang, Harbin, 150081, China
| | - Shuwei Jia
- Department of Physiology, School of Basic Medical Sciences, Harbin Medical University, 157 Baojian Road, Nangang, Harbin, 150081, China
| | - Xiaoran Wang
- Department of Physiology, School of Basic Medical Sciences, Harbin Medical University, 157 Baojian Road, Nangang, Harbin, 150081, China
| | - Ping Wang
- Department of Genetics, School of Basic Medical Sciences, Harbin Medical University, Harbin, China
| | - Yu-Feng Wang
- Department of Physiology, School of Basic Medical Sciences, Harbin Medical University, 157 Baojian Road, Nangang, Harbin, 150081, China.
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Van Den Herrewegen Y, Sanderson TM, Sahu S, De Bundel D, Bortolotto ZA, Smolders I. Side-by-side comparison of the effects of Gq- and Gi-DREADD-mediated astrocyte modulation on intracellular calcium dynamics and synaptic plasticity in the hippocampal CA1. Mol Brain 2021; 14:144. [PMID: 34544455 PMCID: PMC8451082 DOI: 10.1186/s13041-021-00856-w] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Accepted: 09/11/2021] [Indexed: 12/12/2022] Open
Abstract
Astrocytes express a plethora of G protein-coupled receptors (GPCRs) that are crucial for shaping synaptic activity. Upon GPCR activation, astrocytes can respond with transient variations in intracellular Ca2+. In addition, Ca2+-dependent and/or Ca2+-independent release of gliotransmitters can occur, allowing them to engage in bidirectional neuron-astrocyte communication. The development of designer receptors exclusively activated by designer drugs (DREADDs) has facilitated many new discoveries on the roles of astrocytes in both physiological and pathological conditions. They are an excellent tool, as they can target endogenous GPCR-mediated intracellular signal transduction pathways specifically in astrocytes. With increasing interest and accumulating research on this topic, several discrepancies on astrocytic Ca2+ signalling and astrocyte-mediated effects on synaptic plasticity have emerged, preventing a clear-cut consensus about the downstream effects of DREADDs in astrocytes. In the present study, we performed a side-by-side evaluation of the effects of bath application of the DREADD agonist, clozapine-N-oxide (10 µM), on Gq- and Gi-DREADD activation in mouse CA1 hippocampal astrocytes. In doing so, we aimed to avoid confounding factors, such as differences in experimental procedures, and to directly compare the actions of both DREADDs on astrocytic intracellular Ca2+ dynamics and synaptic plasticity in acute hippocampal slices. We used an adeno-associated viral vector approach to transduce dorsal hippocampi of male, 8-week-old C57BL6/J mice, to drive expression of either the Gq-DREADD or Gi-DREADD in CA1 astrocytes. A viral vector lacking the DREADD construct was used to generate controls. Here, we show that agonism of Gq-DREADDs, but not Gi-DREADDs, induced consistent increases in spontaneous astrocytic Ca2+ events. Moreover, we demonstrate that both Gq-DREADD as well as Gi-DREADD-mediated activation of CA1 astrocytes induces long-lasting synaptic potentiation in the hippocampal CA1 Schaffer collateral pathway in the absence of a high frequency stimulus. Moreover, we report for the first time that astrocytic Gi-DREADD activation is sufficient to elicit de novo potentiation. Our data demonstrate that activation of either Gq or Gi pathways drives synaptic potentiation through Ca2+-dependent and Ca2+-independent mechanisms, respectively.
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Affiliation(s)
- Yana Van Den Herrewegen
- Department of Pharmaceutical Chemistry, Drug Analysis and Drug Information, Research Group Experimental Pharmacology, Center for Neurosciences (C4N), Vrije Universiteit Brussel (VUB), Laarbeeklaan 103, 1090, Brussels, Belgium
| | - Thomas M Sanderson
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Tankard's Cl, University Walk, BS8 1TD, Bristol, UK
| | - Surajit Sahu
- Department of Pharmaceutical Chemistry, Drug Analysis and Drug Information, Research Group Experimental Pharmacology, Center for Neurosciences (C4N), Vrije Universiteit Brussel (VUB), Laarbeeklaan 103, 1090, Brussels, Belgium
| | - Dimitri De Bundel
- Department of Pharmaceutical Chemistry, Drug Analysis and Drug Information, Research Group Experimental Pharmacology, Center for Neurosciences (C4N), Vrije Universiteit Brussel (VUB), Laarbeeklaan 103, 1090, Brussels, Belgium
| | - Zuner A Bortolotto
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Tankard's Cl, University Walk, BS8 1TD, Bristol, UK
| | - Ilse Smolders
- Department of Pharmaceutical Chemistry, Drug Analysis and Drug Information, Research Group Experimental Pharmacology, Center for Neurosciences (C4N), Vrije Universiteit Brussel (VUB), Laarbeeklaan 103, 1090, Brussels, Belgium.
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Malchow RP, Tchernookova BK, Choi JIV, Smith PJS, Kramer RH, Kreitzer MA. Review and Hypothesis: A Potential Common Link Between Glial Cells, Calcium Changes, Modulation of Synaptic Transmission, Spreading Depression, Migraine, and Epilepsy-H . Front Cell Neurosci 2021; 15:693095. [PMID: 34539347 PMCID: PMC8446203 DOI: 10.3389/fncel.2021.693095] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Accepted: 06/25/2021] [Indexed: 01/03/2023] Open
Abstract
There is significant evidence to support the notion that glial cells can modulate the strength of synaptic connections between nerve cells, and it has further been suggested that alterations in intracellular calcium are likely to play a key role in this process. However, the molecular mechanism(s) by which glial cells modulate neuronal signaling remains contentiously debated. Recent experiments have suggested that alterations in extracellular H+ efflux initiated by extracellular ATP may play a key role in the modulation of synaptic strength by radial glial cells in the retina and astrocytes throughout the brain. ATP-elicited alterations in H+ flux from radial glial cells were first detected from Müller cells enzymatically dissociated from the retina of tiger salamander using self-referencing H+-selective microelectrodes. The ATP-elicited alteration in H+ efflux was further found to be highly evolutionarily conserved, extending to Müller cells isolated from species as diverse as lamprey, skate, rat, mouse, monkey and human. More recently, self-referencing H+-selective electrodes have been used to detect ATP-elicited alterations in H+ efflux around individual mammalian astrocytes from the cortex and hippocampus. Tied to increases in intracellular calcium, these ATP-induced extracellular acidifications are well-positioned to be key mediators of synaptic modulation. In this article, we examine the evidence supporting H+ as a key modulator of neurotransmission, review data showing that extracellular ATP elicits an increase in H+ efflux from glial cells, and describe the potential signal transduction pathways involved in glial cell-mediated H+ efflux. We then examine the potential role that extracellular H+ released by glia might play in regulating synaptic transmission within the vertebrate retina, and then expand the focus to discuss potential roles in spreading depression, migraine, epilepsy, and alterations in brain rhythms, and suggest that alterations in extracellular H+ may be a unifying feature linking these disparate phenomena.
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Affiliation(s)
- Robert Paul Malchow
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, IL, United States
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, IL, United States
| | - Boriana K. Tchernookova
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, IL, United States
| | - Ji-in Vivien Choi
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, IL, United States
- Stritch School of Medicine, Loyola University, Maywood, IL, United States
| | - Peter J. S. Smith
- Institute for Life Sciences, University of Southampton, Highfield Campus, Southampton, United Kingdom
- Bell Center, Marine Biological Laboratory, Woods Hole, MA, United States
| | - Richard H. Kramer
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, United States
| | - Matthew A. Kreitzer
- Department of Biology, Indiana Wesleyan University, Marion, IN, United States
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Lau BK, Murphy-Royal C, Kaur M, Qiao M, Bains JS, Gordon GR, Borgland SL. Obesity-induced astrocyte dysfunction impairs heterosynaptic plasticity in the orbitofrontal cortex. Cell Rep 2021; 36:109563. [PMID: 34407401 DOI: 10.1016/j.celrep.2021.109563] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Revised: 05/03/2021] [Accepted: 07/28/2021] [Indexed: 11/17/2022] Open
Abstract
Overconsumption of highly palatable, energy-dense food is considered a key driver of the obesity pandemic. The orbitofrontal cortex (OFC) is critical for reward valuation of gustatory signals, yet how the OFC adapts to obesogenic diets is poorly understood. Here, we show that extended access to a cafeteria diet impairs astrocyte glutamate clearance, which leads to a heterosynaptic depression of GABA transmission onto pyramidal neurons of the OFC. This decrease in GABA tone is due to an increase in extrasynaptic glutamate, which acts via metabotropic glutamate receptors to liberate endocannabinoids. This impairs the induction of endocannabinoid-mediated long-term plasticity. The nutritional supplement, N-acetylcysteine rescues this cascade of synaptic impairments by restoring astrocytic glutamate transport. Together, our findings indicate that obesity targets astrocytes to disrupt the delicate balance between excitatory and inhibitory transmission in the OFC.
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Affiliation(s)
- Benjamin K Lau
- Department of Physiology and Pharmacology, Hotchkiss Brain Institute, The University of Calgary, 3330 Hospital Dr. NW, Calgary, Alberta T2N 4N1, Canada
| | - Ciaran Murphy-Royal
- Department of Physiology and Pharmacology, Hotchkiss Brain Institute, The University of Calgary, 3330 Hospital Dr. NW, Calgary, Alberta T2N 4N1, Canada
| | - Manpreet Kaur
- Department of Physiology and Pharmacology, Hotchkiss Brain Institute, The University of Calgary, 3330 Hospital Dr. NW, Calgary, Alberta T2N 4N1, Canada
| | - Min Qiao
- Department of Physiology and Pharmacology, Hotchkiss Brain Institute, The University of Calgary, 3330 Hospital Dr. NW, Calgary, Alberta T2N 4N1, Canada
| | - Jaideep S Bains
- Department of Physiology and Pharmacology, Hotchkiss Brain Institute, The University of Calgary, 3330 Hospital Dr. NW, Calgary, Alberta T2N 4N1, Canada
| | - Grant R Gordon
- Department of Physiology and Pharmacology, Hotchkiss Brain Institute, The University of Calgary, 3330 Hospital Dr. NW, Calgary, Alberta T2N 4N1, Canada
| | - Stephanie L Borgland
- Department of Physiology and Pharmacology, Hotchkiss Brain Institute, The University of Calgary, 3330 Hospital Dr. NW, Calgary, Alberta T2N 4N1, Canada.
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Durkee C, Kofuji P, Navarrete M, Araque A. Astrocyte and neuron cooperation in long-term depression. Trends Neurosci 2021; 44:837-848. [PMID: 34334233 DOI: 10.1016/j.tins.2021.07.004] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Revised: 07/06/2021] [Accepted: 07/07/2021] [Indexed: 01/28/2023]
Abstract
Activity-dependent long-term changes in synaptic transmission known as synaptic plasticity are fundamental processes in brain function and are recognized as the cellular basis of learning and memory. While the neuronal mechanisms underlying synaptic plasticity have been largely identified, the involvement of astrocytes in these processes has been less recognized. However, astrocytes are emerging as important cells that regulate synaptic function by interacting with neurons at tripartite synapses. In this review, we discuss recent evidence suggesting that astrocytes are necessary elements in long-term synaptic depression (LTD). We highlight the mechanistic heterogeneity of astrocyte contribution to this form of synaptic plasticity and propose that astrocytes are integral participants in LTD.
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Affiliation(s)
- Caitlin Durkee
- Department of Neuroscience, University of Minnesota, Minneapolis, MN 55455, USA
| | - Paulo Kofuji
- Department of Neuroscience, University of Minnesota, Minneapolis, MN 55455, USA
| | | | - Alfonso Araque
- Department of Neuroscience, University of Minnesota, Minneapolis, MN 55455, USA.
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61
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Pereira MF, Amaral IM, Lopes C, Leitão C, Madeira D, Lopes JP, Gonçalves FQ, Canas PM, Cunha RA, Agostinho P. l-α-aminoadipate causes astrocyte pathology with negative impact on mouse hippocampal synaptic plasticity and memory. FASEB J 2021; 35:e21726. [PMID: 34196433 DOI: 10.1096/fj.202100336r] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2021] [Revised: 05/12/2021] [Accepted: 05/24/2021] [Indexed: 12/26/2022]
Abstract
Increasing evidence shows that astrocytes, by releasing and uptaking neuroactive molecules, regulate synaptic plasticity, considered the neurophysiological basis of memory. This study investigated the impact of l-α-aminoadipate (l-AA) on astrocytes which sense and respond to stimuli at the synaptic level and modulate hippocampal long-term potentiation (LTP) and memory. l-AA selectivity toward astrocytes was proposed in the early 70's and further tested in different systems. Although it has been used for impairing the astrocytic function, its effects appear to be variable in different brain regions. To test the effects of l-AA in the hippocampus of male C57Bl/6 mice we performed two different treatments (ex vivo and in vivo) and took advantage of other compounds that were reported to affect astrocytes. l-AA superfusion did not affect the basal synaptic transmission but decreased LTP magnitude. Likewise, trifluoroacetate and dihydrokainate decreased LTP magnitude and occluded the effect of l-AA on synaptic plasticity, confirming l-AA selectivity. l-AA superfusion altered astrocyte morphology, increasing the length and complexity of their processes. In vivo, l-AA intracerebroventricular injection not only reduced the astrocytic markers but also LTP magnitude and impaired hippocampal-dependent memory in mice. Interestingly, d-serine administration recovered hippocampal LTP reduction triggered by l-AA (2 h exposure in hippocampal slices), whereas in mice injected with l-AA, the superfusion of d-serine did not fully rescue LTP magnitude. Overall, these data show that both l-AA treatments affect astrocytes differently, astrocytic activation or loss, with similar negative outcomes on hippocampal LTP, implying that opposite astrocytic adaptive alterations are equally detrimental for synaptic plasticity.
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Affiliation(s)
| | - Inês M Amaral
- Center for Neuroscience and Cell Biology, CNC, Coimbra, Portugal
| | - Cátia Lopes
- Center for Neuroscience and Cell Biology, CNC, Coimbra, Portugal
| | - Catarina Leitão
- Center for Neuroscience and Cell Biology, CNC, Coimbra, Portugal
| | - Daniela Madeira
- Center for Neuroscience and Cell Biology, CNC, Coimbra, Portugal.,Faculty of Medicine, University of Coimbra, FMUC, Coimbra, Portugal
| | - João P Lopes
- Center for Neuroscience and Cell Biology, CNC, Coimbra, Portugal
| | | | - Paula M Canas
- Center for Neuroscience and Cell Biology, CNC, Coimbra, Portugal
| | - Rodrigo A Cunha
- Center for Neuroscience and Cell Biology, CNC, Coimbra, Portugal.,Faculty of Medicine, University of Coimbra, FMUC, Coimbra, Portugal
| | - Paula Agostinho
- Center for Neuroscience and Cell Biology, CNC, Coimbra, Portugal.,Faculty of Medicine, University of Coimbra, FMUC, Coimbra, Portugal
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62
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Ribot J, Breton R, Calvo CF, Moulard J, Ezan P, Zapata J, Samama K, Moreau M, Bemelmans AP, Sabatet V, Dingli F, Loew D, Milleret C, Billuart P, Dallérac G, Rouach N. Astrocytes close the mouse critical period for visual plasticity. Science 2021; 373:77-81. [PMID: 34210880 DOI: 10.1126/science.abf5273] [Citation(s) in RCA: 43] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2020] [Accepted: 05/13/2021] [Indexed: 12/26/2022]
Abstract
Brain postnatal development is characterized by critical periods of experience-dependent remodeling of neuronal circuits. Failure to end these periods results in neurodevelopmental disorders. The cellular processes defining critical-period timing remain unclear. Here, we show that in the mouse visual cortex, astrocytes control critical-period closure. We uncover the underlying pathway, which involves astrocytic regulation of the extracellular matrix, allowing interneuron maturation. Unconventional astrocyte connexin signaling hinders expression of extracellular matrix-degrading enzyme matrix metalloproteinase 9 (MMP9) through RhoA-guanosine triphosphatase activation. Thus, astrocytes not only influence the activity of single synapses but also are key elements in the experience-dependent wiring of brain circuits.
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Affiliation(s)
- Jérôme Ribot
- Center for Interdisciplinary Research in Biology, Collège de France, CNRS UMR 7241, INSERM U1050, Labex Memolife, PSL Research University, Paris, France
| | - Rachel Breton
- Center for Interdisciplinary Research in Biology, Collège de France, CNRS UMR 7241, INSERM U1050, Labex Memolife, PSL Research University, Paris, France.,Doctoral School N°568, Paris Saclay University, PSL Research University, Le Kremlin Bicetre, France.,Université Paris-Saclay, CNRS, Institut des neurosciences Paris-Saclay, Gif-sur-Yvette, France
| | - Charles-Félix Calvo
- Center for Interdisciplinary Research in Biology, Collège de France, CNRS UMR 7241, INSERM U1050, Labex Memolife, PSL Research University, Paris, France
| | - Julien Moulard
- Center for Interdisciplinary Research in Biology, Collège de France, CNRS UMR 7241, INSERM U1050, Labex Memolife, PSL Research University, Paris, France.,Doctoral School N°158, Sorbonne University, Paris, France
| | - Pascal Ezan
- Center for Interdisciplinary Research in Biology, Collège de France, CNRS UMR 7241, INSERM U1050, Labex Memolife, PSL Research University, Paris, France
| | - Jonathan Zapata
- Center for Interdisciplinary Research in Biology, Collège de France, CNRS UMR 7241, INSERM U1050, Labex Memolife, PSL Research University, Paris, France
| | - Kevin Samama
- Center for Interdisciplinary Research in Biology, Collège de France, CNRS UMR 7241, INSERM U1050, Labex Memolife, PSL Research University, Paris, France
| | - Matthieu Moreau
- Université de Paris, Institute of Psychiatry and Neuroscience of Paris (IPNP), INSERM U1266, Genetic and Development of Cerebral Cortex Laboratory, GHU Paris Psychiatrie et Neurosciences, Hôpital Saint Anne, Paris, France
| | - Alexis-Pierre Bemelmans
- Commissariat à l'Energie Atomique et aux Energies Alternatives (CEA), Département de la Recherche Fondamentale, Institut de biologie François Jacob, MIRCen, and CNRS UMR 9199, Université Paris-Saclay, Neurodegenerative Diseases Laboratory, Fontenay-aux-Roses, France
| | - Valentin Sabatet
- Institut Curie, PSL Research University, Mass Spectrometry and Proteomics Laboratory, Paris, France
| | - Florent Dingli
- Institut Curie, PSL Research University, Mass Spectrometry and Proteomics Laboratory, Paris, France
| | - Damarys Loew
- Institut Curie, PSL Research University, Mass Spectrometry and Proteomics Laboratory, Paris, France
| | - Chantal Milleret
- Center for Interdisciplinary Research in Biology, Collège de France, CNRS UMR 7241, INSERM U1050, Labex Memolife, PSL Research University, Paris, France
| | - Pierre Billuart
- Université de Paris, Institute of Psychiatry and Neuroscience of Paris (IPNP), INSERM U1266, Genetic and Development of Cerebral Cortex Laboratory, GHU Paris Psychiatrie et Neurosciences, Hôpital Saint Anne, Paris, France
| | - Glenn Dallérac
- Center for Interdisciplinary Research in Biology, Collège de France, CNRS UMR 7241, INSERM U1050, Labex Memolife, PSL Research University, Paris, France
| | - Nathalie Rouach
- Center for Interdisciplinary Research in Biology, Collège de France, CNRS UMR 7241, INSERM U1050, Labex Memolife, PSL Research University, Paris, France.
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63
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Sarazin MXB, Victor J, Medernach D, Naudé J, Delord B. Online Learning and Memory of Neural Trajectory Replays for Prefrontal Persistent and Dynamic Representations in the Irregular Asynchronous State. Front Neural Circuits 2021; 15:648538. [PMID: 34305535 PMCID: PMC8298038 DOI: 10.3389/fncir.2021.648538] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Accepted: 05/31/2021] [Indexed: 11/13/2022] Open
Abstract
In the prefrontal cortex (PFC), higher-order cognitive functions and adaptive flexible behaviors rely on continuous dynamical sequences of spiking activity that constitute neural trajectories in the state space of activity. Neural trajectories subserve diverse representations, from explicit mappings in physical spaces to generalized mappings in the task space, and up to complex abstract transformations such as working memory, decision-making and behavioral planning. Computational models have separately assessed learning and replay of neural trajectories, often using unrealistic learning rules or decoupling simulations for learning from replay. Hence, the question remains open of how neural trajectories are learned, memorized and replayed online, with permanently acting biological plasticity rules. The asynchronous irregular regime characterizing cortical dynamics in awake conditions exerts a major source of disorder that may jeopardize plasticity and replay of locally ordered activity. Here, we show that a recurrent model of local PFC circuitry endowed with realistic synaptic spike timing-dependent plasticity and scaling processes can learn, memorize and replay large-size neural trajectories online under asynchronous irregular dynamics, at regular or fast (sped-up) timescale. Presented trajectories are quickly learned (within seconds) as synaptic engrams in the network, and the model is able to chunk overlapping trajectories presented separately. These trajectory engrams last long-term (dozen hours) and trajectory replays can be triggered over an hour. In turn, we show the conditions under which trajectory engrams and replays preserve asynchronous irregular dynamics in the network. Functionally, spiking activity during trajectory replays at regular timescale accounts for both dynamical coding with temporal tuning in individual neurons, persistent activity at the population level, and large levels of variability consistent with observed cognitive-related PFC dynamics. Together, these results offer a consistent theoretical framework accounting for how neural trajectories can be learned, memorized and replayed in PFC networks circuits to subserve flexible dynamic representations and adaptive behaviors.
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Affiliation(s)
- Matthieu X B Sarazin
- Institut des Systèmes Intelligents et de Robotique, CNRS, Inserm, Sorbonne Université, Paris, France
| | - Julie Victor
- CEA Paris-Saclay, CNRS, NeuroSpin, Saclay, France
| | - David Medernach
- Institut des Systèmes Intelligents et de Robotique, CNRS, Inserm, Sorbonne Université, Paris, France
| | - Jérémie Naudé
- Neuroscience Paris Seine - Institut de biologie Paris Seine, CNRS, Inserm, Sorbonne Université, Paris, France
| | - Bruno Delord
- Institut des Systèmes Intelligents et de Robotique, CNRS, Inserm, Sorbonne Université, Paris, France
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64
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Ma Z, Wei L, Du X, Hou S, Chen F, Jiao Q, Liu A, Liu S, Wang J, Shen H. Two-photon calcium imaging of neuronal and astrocytic responses: the influence of electrical stimulus parameters and calcium signaling mechanisms. J Neural Eng 2021; 18. [PMID: 34130271 DOI: 10.1088/1741-2552/ac0b50] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Accepted: 06/15/2021] [Indexed: 12/30/2022]
Abstract
Objective. Electrical brain stimulation has been used to ameliorate symptoms associated with neurologic and psychiatric disorders. The astrocytic activation and its interaction with neurons may contribute to the therapeutic effects of electrical stimulation. However, how the astrocytic activity is affected by electrical stimulation and its calcium signaling mechanisms remain largely unknown. This study is to explore the influence of electrical stimulus parameters on cellular calcium responses and corresponding calcium signaling mechanisms, with a focus on the heretofore largely overlooked astrocytes.Approach. Usingin vivotwo-photon microscopy in mouse somatosensory cortex, the calcium activity in neurons and astrocytes were recorded.Main results. The cathodal stimulation evoked larger responses in both neurons and astrocytes than anodal stimulation. Both neuronal and astrocytic response profiles exhibited the unimodal frequency dependency, the astrocytes prefer higher frequency stimulation than neurons. Astrocytes need longer pulse width and higher current intensity than neurons to activate. Compared to neurons, the astrocytes were not capable of keeping sustained calcium elevation during prolonged electrical stimulation. The neuronal Ca2+influx involves postsynaptic effects and direct depolarization. The Ca2+surge of astrocytes has a neuronal origin, the noradrenergic and glutamatergic signaling act synergistically to induce astrocytic activity.Significance. The astrocytic activity can be regulated by manipulating stimulus parameters and its calcium activation should be fully considered when interpreting the mechanisms of action of electrical neuromodulation. This study brings considerable benefits in the application of electrical stimulation and provides useful insights into cortical signal transduction, which contributes to the understanding of mechanisms underlying the therapeutic efficacy of electrical stimulation for neurorehabilitation applications.
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Affiliation(s)
- Zengguang Ma
- School of Biomedical Engineering, Tianjin Medical University, 22 Qixiangtai Road, Tianjin 300070, China
| | - Liangpeng Wei
- School of Biomedical Engineering, Tianjin Medical University, 22 Qixiangtai Road, Tianjin 300070, China
| | - Xiaolang Du
- Department of Pharmacy, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin's Clinical Research Center for Cancer, Tianjin 300060, China
| | - Shaowei Hou
- School of Biomedical Engineering, Tianjin Medical University, 22 Qixiangtai Road, Tianjin 300070, China
| | - Feng Chen
- School of Biomedical Engineering, Tianjin Medical University, 22 Qixiangtai Road, Tianjin 300070, China
| | - Qingyan Jiao
- School of Biomedical Engineering, Tianjin Medical University, 22 Qixiangtai Road, Tianjin 300070, China
| | - Aili Liu
- School of Biomedical Engineering, Tianjin Medical University, 22 Qixiangtai Road, Tianjin 300070, China
| | - Shujing Liu
- School of Biomedical Engineering, Tianjin Medical University, 22 Qixiangtai Road, Tianjin 300070, China
| | - Junsong Wang
- School of Biomedical Engineering, Tianjin Medical University, 22 Qixiangtai Road, Tianjin 300070, China
| | - Hui Shen
- School of Biomedical Engineering, Tianjin Medical University, 22 Qixiangtai Road, Tianjin 300070, China.,Research Institute of Neurology, General Hospital, Tianjin Medical University, Tianjin 300052, China
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65
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Huntington TE, Srinivasan R. Adeno-Associated Virus Expression of α-Synuclein as a Tool to Model Parkinson's Disease: Current Understanding and Knowledge Gaps. Aging Dis 2021; 12:1120-1137. [PMID: 34221553 PMCID: PMC8219504 DOI: 10.14336/ad.2021.0517] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Accepted: 05/16/2021] [Indexed: 12/12/2022] Open
Abstract
Parkinson's disease (PD) is the second most common neurodegenerative disorder in the aging population and is characterized by a constellation of motor and non-motor symptoms. The abnormal aggregation and spread of alpha-synuclein (α-syn) is thought to underlie the loss of dopaminergic (DA) neurons in the substantia nigra pars compacta (SNc), leading to the development of PD. It is in this context that the use of adeno-associated viruses (AAVs) to express a-syn in the rodent midbrain has become a popular tool to model SNc DA neuron loss during PD. In this review, we summarize results from two decades of experiments using AAV-mediated a-syn expression in rodents to model PD. Specifically, we outline aspects of AAV vectors that are particularly relevant to modeling a-syn dysfunction in rodent models of PD such as changes in striatal neurochemistry, a-syn biochemistry, and PD-related behaviors resulting from AAV-mediated a-syn expression in the midbrain. Finally, we discuss the emerging role of astrocytes in propagating a-syn pathology, and point to future directions for employing AAVs as a tool to better understand how astrocytes contribute to a-syn pathology during the development of PD. We envision that lessons learned from two decades of utilizing AAVs to express a-syn in the rodent brain will enable us to develop an optimized set of parameters for gaining a better understanding of how a-syn leads to the development of PD.
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Affiliation(s)
- Taylor E Huntington
- Department of Neuroscience & Experimental Therapeutics, Texas A&M University College of Medicine, 8447 Riverside Pkwy, Bryan, TX 77807, USA.
- Texas A&M Institute for Neuroscience (TAMIN), College Station, TX 77843, USA
| | - Rahul Srinivasan
- Department of Neuroscience & Experimental Therapeutics, Texas A&M University College of Medicine, 8447 Riverside Pkwy, Bryan, TX 77807, USA.
- Texas A&M Institute for Neuroscience (TAMIN), College Station, TX 77843, USA
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66
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Stone TW. Relationships and Interactions between Ionotropic Glutamate Receptors and Nicotinic Receptors in the CNS. Neuroscience 2021; 468:321-365. [PMID: 34111447 DOI: 10.1016/j.neuroscience.2021.06.007] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2021] [Revised: 06/03/2021] [Accepted: 06/04/2021] [Indexed: 02/07/2023]
Abstract
Although ionotropic glutamate receptors and nicotinic receptors for acetylcholine (ACh) have usually been studied separately, they are often co-localized and functionally inter-dependent. The objective of this review is to survey the evidence for interactions between the two receptor families and the mechanisms underlying them. These include the mutual regulation of subunit expression, which change the NMDA:AMPA response balance, and the existence of multi-functional receptor complexes which make it difficult to distinguish between individual receptor sites, especially in vivo. This is followed by analysis of the functional relationships between the receptors from work on transmitter release, cellular electrophysiology and aspects of behavior where these can contribute to understanding receptor interactions. It is clear that nicotinic receptors (nAChRs) on axonal terminals directly regulate the release of glutamate and other neurotransmitters, α7-nAChRs generally promoting release. Hence, α7-nAChR responses will be prevented not only by a nicotinic antagonist, but also by compounds blocking the indirectly activated glutamate receptors. This accounts for the apparent anticholinergic activity of some glutamate antagonists, including the endogenous antagonist kynurenic acid. The activation of presynaptic nAChRs is by the ambient levels of ACh released from pre-terminal synapses, varicosities and glial cells, acting as a 'volume neurotransmitter' on synaptic and extrasynaptic sites. In addition, ACh and glutamate are released as CNS co-transmitters, including 'cholinergic' synapses onto spinal Renshaw cells. It is concluded that ACh should be viewed primarily as a modulator of glutamatergic neurotransmission by regulating the release of glutamate presynaptically, and the location, subunit composition, subtype balance and sensitivity of glutamate receptors, and not primarily as a classical fast neurotransmitter. These conclusions and caveats should aid clarification of the sites of action of glutamate and nicotinic receptor ligands in the search for new centrally-acting drugs.
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Affiliation(s)
- Trevor W Stone
- The Kennedy Institute of Rheumatology, University of Oxford, Oxford OX3 7FY, UK; Institute of Neuroscience, University of Glasgow, G12 8QQ, UK.
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67
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Mazaud D, Capano A, Rouach N. The many ways astroglial connexins regulate neurotransmission and behavior. Glia 2021; 69:2527-2545. [PMID: 34101261 DOI: 10.1002/glia.24040] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2020] [Revised: 05/17/2021] [Accepted: 05/21/2021] [Indexed: 12/18/2022]
Abstract
Astrocytes have emerged as major players in the brain, contributing to many functions such as energy supply, neurotransmission, and behavior. They accomplish these functions in part via their capacity to form widespread intercellular networks and to release neuroactive factors, which can modulate neurotransmission at different levels, from individual synapses to neuronal networks. The extensive network communication of astrocytes is primarily mediated by gap junction channels composed of two connexins, Cx30 and Cx43, which present distinct temporal and spatial expression patterns. Yet, astroglial connexins are also involved in direct exchange with the extracellular space via hemichannels, as well as in adhesion and signaling processes via unconventional nonchannel functions. Accumulating evidence indicate that astrocytes modulate neurotransmission and behavior through these diverse connexin functions. We here review the many ways astroglial connexins regulate neuronal activity from the molecular level to behavior.
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Affiliation(s)
- David Mazaud
- Neuroglial Interactions in Cerebral Physiology and Pathologies, Center for Interdisciplinary Research in Biology, Collège de France, CNRS UMR 7241, INSERM U1050, Labex Memolife, PSL Research University, Paris, France
| | - Anna Capano
- Neuroglial Interactions in Cerebral Physiology and Pathologies, Center for Interdisciplinary Research in Biology, Collège de France, CNRS UMR 7241, INSERM U1050, Labex Memolife, PSL Research University, Paris, France.,Doctoral School N°158, Sorbonne University, Paris, France
| | - Nathalie Rouach
- Neuroglial Interactions in Cerebral Physiology and Pathologies, Center for Interdisciplinary Research in Biology, Collège de France, CNRS UMR 7241, INSERM U1050, Labex Memolife, PSL Research University, Paris, France
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68
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Lia A, Henriques VJ, Zonta M, Chiavegato A, Carmignoto G, Gómez-Gonzalo M, Losi G. Calcium Signals in Astrocyte Microdomains, a Decade of Great Advances. Front Cell Neurosci 2021; 15:673433. [PMID: 34163329 PMCID: PMC8216559 DOI: 10.3389/fncel.2021.673433] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2021] [Accepted: 04/23/2021] [Indexed: 12/13/2022] Open
Abstract
The glial cells astrocytes have long been recognized as important neuron-supporting elements in brain development, homeostasis, and metabolism. After the discovery that the reciprocal communication between astrocytes and neurons is a fundamental mechanism in the modulation of neuronal synaptic communication, over the last two decades astrocytes became a hot topic in neuroscience research. Crucial to their functional interactions with neurons are the cytosolic Ca2+ elevations that mediate gliotransmission. Large attention has been posed to the so-called Ca2+microdomains, dynamic Ca2+ changes spatially restricted to fine astrocytic processes including perisynaptic astrocytic processes (PAPs). With presynaptic terminals and postsynaptic neuronal membranes, PAPs compose the tripartite synapse. The distinct spatial-temporal features and functional roles of astrocyte microdomain Ca2+ activity remain poorly defined. However, thanks to the development of genetically encoded Ca2+ indicators (GECIs), advanced microscopy techniques, and innovative analytical approaches, Ca2+ transients in astrocyte microdomains were recently studied in unprecedented detail. These events have been observed to occur much more frequently (∼50–100-fold) and dynamically than somatic Ca2+ elevations with mechanisms that likely involve both IP3-dependent and -independent pathways. Further progress aimed to clarify the complex, dynamic machinery responsible for astrocytic Ca2+ activity at microdomains is a crucial step in our understanding of the astrocyte role in brain function and may also reveal astrocytes as novel therapeutic targets for different brain diseases. Here, we review the most recent studies that improve our mechanistic understanding of the essential features of astrocyte Ca2+ microdomains.
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Affiliation(s)
- Annamaria Lia
- Neuroscience Institute, National Research Council (IN-CNR), Padua, Italy.,Department of Biomedical Sciences, University of Padua, Padua, Italy
| | - Vanessa Jorge Henriques
- Neuroscience Institute, National Research Council (IN-CNR), Padua, Italy.,Department of Biomedical Sciences, University of Padua, Padua, Italy
| | - Micaela Zonta
- Neuroscience Institute, National Research Council (IN-CNR), Padua, Italy.,Department of Biomedical Sciences, University of Padua, Padua, Italy
| | - Angela Chiavegato
- Department of Biomedical Sciences, University of Padua, Padua, Italy
| | - Giorgio Carmignoto
- Neuroscience Institute, National Research Council (IN-CNR), Padua, Italy.,Department of Biomedical Sciences, University of Padua, Padua, Italy
| | - Marta Gómez-Gonzalo
- Neuroscience Institute, National Research Council (IN-CNR), Padua, Italy.,Department of Biomedical Sciences, University of Padua, Padua, Italy
| | - Gabriele Losi
- Neuroscience Institute, National Research Council (IN-CNR), Padua, Italy.,Department of Biomedical Sciences, University of Padua, Padua, Italy
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69
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van Putten MJ, Fahlke C, Kafitz KW, Hofmeijer J, Rose CR. Dysregulation of Astrocyte Ion Homeostasis and Its Relevance for Stroke-Induced Brain Damage. Int J Mol Sci 2021; 22:5679. [PMID: 34073593 PMCID: PMC8198632 DOI: 10.3390/ijms22115679] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Revised: 05/21/2021] [Accepted: 05/22/2021] [Indexed: 12/14/2022] Open
Abstract
Ischemic stroke is a leading cause of mortality and chronic disability. Either recovery or progression towards irreversible failure of neurons and astrocytes occurs within minutes to days, depending on remaining perfusion levels. Initial damage arises from energy depletion resulting in a failure to maintain homeostasis and ion gradients between extra- and intracellular spaces. Astrocytes play a key role in these processes and are thus central players in the dynamics towards recovery or progression of stroke-induced brain damage. Here, we present a synopsis of the pivotal functions of astrocytes at the tripartite synapse, which form the basis of physiological brain functioning. We summarize the evidence of astrocytic failure and its consequences under ischemic conditions. Special emphasis is put on the homeostasis and stroke-induced dysregulation of the major monovalent ions, namely Na+, K+, H+, and Cl-, and their involvement in maintenance of cellular volume and generation of cerebral edema.
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Affiliation(s)
- Michel J.A.M. van Putten
- Department of Clinical Neurophysiology, University of Twente, 7522 NB Enschede, The Netherlands; (M.J.A.M.v.P.); (J.H.)
| | - Christoph Fahlke
- Institut für Biologische Informationsprozesse, Molekular-und Zellphysiologie (IBI-1), Forschungszentrum Jülich, 52425 Jülich, Germany;
| | - Karl W. Kafitz
- Institute of Neurobiology, Heinrich Heine University Düsseldorf, 40225 Düsseldorf, Germany;
| | - Jeannette Hofmeijer
- Department of Clinical Neurophysiology, University of Twente, 7522 NB Enschede, The Netherlands; (M.J.A.M.v.P.); (J.H.)
| | - Christine R. Rose
- Institute of Neurobiology, Heinrich Heine University Düsseldorf, 40225 Düsseldorf, Germany;
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70
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Chiareli RA, Carvalho GA, Marques BL, Mota LS, Oliveira-Lima OC, Gomes RM, Birbrair A, Gomez RS, Simão F, Klempin F, Leist M, Pinto MCX. The Role of Astrocytes in the Neurorepair Process. Front Cell Dev Biol 2021; 9:665795. [PMID: 34113618 PMCID: PMC8186445 DOI: 10.3389/fcell.2021.665795] [Citation(s) in RCA: 43] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Accepted: 04/29/2021] [Indexed: 12/17/2022] Open
Abstract
Astrocytes are highly specialized glial cells responsible for trophic and metabolic support of neurons. They are associated to ionic homeostasis, the regulation of cerebral blood flow and metabolism, the modulation of synaptic activity by capturing and recycle of neurotransmitters and maintenance of the blood-brain barrier. During injuries and infections, astrocytes act in cerebral defense through heterogeneous and progressive changes in their gene expression, morphology, proliferative capacity, and function, which is known as reactive astrocytes. Thus, reactive astrocytes release several signaling molecules that modulates and contributes to the defense against injuries and infection in the central nervous system. Therefore, deciphering the complex signaling pathways of reactive astrocytes after brain damage can contribute to the neuroinflammation control and reveal new molecular targets to stimulate neurorepair process. In this review, we present the current knowledge about the role of astrocytes in brain damage and repair, highlighting the cellular and molecular bases involved in synaptogenesis and neurogenesis. In addition, we present new approaches to modulate the astrocytic activity and potentiates the neurorepair process after brain damage.
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Affiliation(s)
| | | | | | - Lennia Soares Mota
- Department of Pharmacology, Federal University of Goias, Goiânia, Brazil
| | | | | | - Alexander Birbrair
- Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, Brazil
| | - Renato Santiago Gomez
- Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, Brazil
| | - Fabrício Simão
- Research Division, Vascular Cell Biology, Joslin Diabetes Center and Harvard Medical School, Boston, MA, United States
| | | | - Marcel Leist
- Konstanz Research School Chemical Biology, University of Konstanz, Konstanz, Germany
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71
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Chang CY, Luo DZ, Pei JC, Kuo MC, Hsieh YC, Lai WS. Not Just a Bystander: The Emerging Role of Astrocytes and Research Tools in Studying Cognitive Dysfunctions in Schizophrenia. Int J Mol Sci 2021; 22:ijms22105343. [PMID: 34069523 PMCID: PMC8160762 DOI: 10.3390/ijms22105343] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Revised: 05/14/2021] [Accepted: 05/14/2021] [Indexed: 12/16/2022] Open
Abstract
Cognitive dysfunction is one of the core symptoms in schizophrenia, and it is predictive of functional outcomes and therefore useful for treatment targets. Rather than improving cognitive deficits, currently available antipsychotics mainly focus on positive symptoms, targeting dopaminergic/serotoninergic neurons and receptors in the brain. Apart from investigating the neural mechanisms underlying schizophrenia, emerging evidence indicates the importance of glial cells in brain structure development and their involvement in cognitive functions. Although the etiopathology of astrocytes in schizophrenia remains unclear, accumulated evidence reveals that alterations in gene expression and astrocyte products have been reported in schizophrenic patients. To further investigate the role of astrocytes in schizophrenia, we highlighted recent progress in the investigation of the effect of astrocytes on abnormalities in glutamate transmission and impairments in the blood–brain barrier. Recent advances in animal models and behavioral methods were introduced to examine schizophrenia-related cognitive deficits and negative symptoms. We also highlighted several experimental tools that further elucidate the role of astrocytes. Instead of focusing on schizophrenia as a neuron-specific disorder, an additional astrocytic perspective provides novel and promising insight into its causal mechanisms and treatment. The involvement of astrocytes in the pathogenesis of schizophrenia and other brain disorders is worth further investigation.
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Affiliation(s)
- Chia-Yuan Chang
- Department of Psychology, National Taiwan University, Taipei 10617, Taiwan; (C.-Y.C.); (D.-Z.L.); (J.-C.P.); (Y.-C.H.)
- Neurobiology and Cognitive Science Center, National Taiwan University, Taipei 10617, Taiwan;
| | - Da-Zhong Luo
- Department of Psychology, National Taiwan University, Taipei 10617, Taiwan; (C.-Y.C.); (D.-Z.L.); (J.-C.P.); (Y.-C.H.)
| | - Ju-Chun Pei
- Department of Psychology, National Taiwan University, Taipei 10617, Taiwan; (C.-Y.C.); (D.-Z.L.); (J.-C.P.); (Y.-C.H.)
| | - Ming-Che Kuo
- Neurobiology and Cognitive Science Center, National Taiwan University, Taipei 10617, Taiwan;
- Department of Neurology, National Taiwan University Hospital, Taipei 100225, Taiwan
| | - Yi-Chen Hsieh
- Department of Psychology, National Taiwan University, Taipei 10617, Taiwan; (C.-Y.C.); (D.-Z.L.); (J.-C.P.); (Y.-C.H.)
| | - Wen-Sung Lai
- Department of Psychology, National Taiwan University, Taipei 10617, Taiwan; (C.-Y.C.); (D.-Z.L.); (J.-C.P.); (Y.-C.H.)
- Neurobiology and Cognitive Science Center, National Taiwan University, Taipei 10617, Taiwan;
- Graduate Institute of Brain and Mind Sciences, National Taiwan University, Taipei 10617, Taiwan
- Correspondence: ; Tel.: +886-2-3366-3112; Fax: +886-2-3362-9909
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72
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Tan CX, Eroglu C. Cell adhesion molecules regulating astrocyte-neuron interactions. Curr Opin Neurobiol 2021; 69:170-177. [PMID: 33957433 DOI: 10.1016/j.conb.2021.03.015] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Revised: 03/23/2021] [Accepted: 03/24/2021] [Indexed: 12/15/2022]
Abstract
A tripartite synapse comprises a neuronal presynaptic axon and a postsynaptic dendrite, which are closely ensheathed by a perisynaptic astrocyte process. Through their structural and functional association with thousands of neuronal synapses, astrocytes regulate synapse formation and function. Recent work revealed a diverse range of cell adhesion-based mechanisms that mediate astrocyte-synapse interactions at tripartite synapses. Here, we will review some of these findings unveiling a highly dynamic bidirectional signaling between astrocytes and synapses, which orchestrates astrocyte morphological maturation and synapse development. Moreover, we will discuss the roles of these newly discovered molecular pathways in brain physiology and function both in health and disease.
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Affiliation(s)
- Christabel X Tan
- Department of Cell Biology, Duke University Medical Center, Durham, NC, 27710, USA
| | - Cagla Eroglu
- Department of Cell Biology, Duke University Medical Center, Durham, NC, 27710, USA; Department of Neurobiology, Duke University Medical Center, Durham, NC, 27710, USA; Duke Institute for Brain Sciences, Durham, NC, 27710, USA; Regeneration Next Initiative, Duke University, Durham, NC, 27710, USA.
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73
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McCann MS, Maguire-Zeiss KA. Environmental toxicants in the brain: A review of astrocytic metabolic dysfunction. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2021; 84:103608. [PMID: 33556584 DOI: 10.1016/j.etap.2021.103608] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Revised: 01/24/2021] [Accepted: 01/29/2021] [Indexed: 06/12/2023]
Abstract
Exposure to environmental toxicants is linked to long-term adverse outcomes in the brain and involves the dysfunction of glial and neuronal cells. Astrocytes, the most numerous cell type, are increasingly implicated in the pathogenesis of many diseases of the central nervous system, including neurodegenerative diseases. Astrocytes are critical for proper brain function in part due to their robust antioxidant and unique metabolic capabilities. Additionally, astrocytes are positioned both at the blood-brain barrier, where they are the primary responders to xenobiotic penetrance of the CNS, and at synapses where they are in close contact with neurons and synaptic machinery. While exposure to several classes of environmental toxicants, including chlorinated and fluorinated compounds, and trace metals, have been implicated in neurodegenerative diseases, their impact on astrocytes represents an important and growing field of research. Here, we review existing literature focused on the impact of a range of synthetic compounds on astrocytic function. We focus specifically on perturbed metabolic processes in response to these compounds and consider how perturbation of these pathways impacts disease pathogenesis.
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Affiliation(s)
- Mondona S McCann
- Interdisciplinary Program in Neuroscience, Georgetown University Medical Center, Washington, DC, 20057, United States.
| | - Kathleen A Maguire-Zeiss
- Interdisciplinary Program in Neuroscience, Georgetown University Medical Center, Washington, DC, 20057, United States; Department of Neuroscience, Georgetown University Medical Center, Washington, DC, 20057, United States
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74
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Choi JIV, Tchernookova BK, Kumar W, Kiedrowski L, Goeke C, Guizzetti M, Larson J, Kreitzer MA, Malchow RP. Extracellular ATP-Induced Alterations in Extracellular H + Fluxes From Cultured Cortical and Hippocampal Astrocytes. Front Cell Neurosci 2021; 15:640217. [PMID: 33994945 PMCID: PMC8120152 DOI: 10.3389/fncel.2021.640217] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Accepted: 03/19/2021] [Indexed: 12/18/2022] Open
Abstract
Small alterations in the level of extracellular H+ can profoundly alter neuronal activity throughout the nervous system. In this study, self-referencing H+-selective microelectrodes were used to examine extracellular H+ fluxes from individual astrocytes. Activation of astrocytes cultured from mouse hippocampus and rat cortex with extracellular ATP produced a pronounced increase in extracellular H+ flux. The ATP-elicited increase in H+ flux appeared to be independent of bicarbonate transport, as ATP increased H+ flux regardless of whether the primary extracellular pH buffer was 26 mM bicarbonate or 1 mM HEPES, and persisted when atmospheric levels of CO2 were replaced by oxygen. Adenosine failed to elicit any change in extracellular H+ fluxes, and ATP-mediated increases in H+ flux were inhibited by the P2 inhibitors suramin and PPADS suggesting direct activation of ATP receptors. Extracellular ATP also induced an intracellular rise in calcium in cultured astrocytes, and ATP-induced rises in both calcium and H+ efflux were significantly attenuated when calcium re-loading into the endoplasmic reticulum was inhibited by thapsigargin. Replacement of extracellular sodium with choline did not significantly reduce the size of the ATP-induced increases in H+ flux, and the increases in H+ flux were not significantly affected by addition of EIPA, suggesting little involvement of Na+/H+ exchangers in ATP-elicited increases in H+ flux. Given the high sensitivity of voltage-sensitive calcium channels on neurons to small changes in levels of free H+, we hypothesize that the ATP-mediated extrusion of H+ from astrocytes may play a key role in regulating signaling at synapses within the nervous system.
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Affiliation(s)
- Ji-In Vivien Choi
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, IL, United States.,Stritch School of Medicine, Loyola University, Maywood, IL, United States
| | - Boriana K Tchernookova
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, IL, United States
| | - Wasan Kumar
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, IL, United States
| | - Lech Kiedrowski
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, IL, United States.,Spot Cells LLC, Chicago, IL, United States
| | - Calla Goeke
- VA Portland Health Care System, Portland, OR, United States.,Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR, United States
| | - Marina Guizzetti
- VA Portland Health Care System, Portland, OR, United States.,Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR, United States
| | - John Larson
- Department of Psychiatry, University of Illinois at Chicago, Chicago, IL, United States
| | - Matthew A Kreitzer
- Department of Biology, Indiana Wesleyan University, Marion, IN, United States
| | - Robert Paul Malchow
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, IL, United States.,Department Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, IL, United States
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75
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Aryal SP, Fu X, Sandin JN, Neupane KR, Lakes JE, Grady ME, Richards CI. Nicotine induces morphological and functional changes in astrocytes via nicotinic receptor activity. Glia 2021; 69:2037-2053. [PMID: 33851731 DOI: 10.1002/glia.24011] [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: 09/17/2020] [Revised: 03/26/2021] [Accepted: 04/08/2021] [Indexed: 01/16/2023]
Abstract
Nicotine is a highly addictive compound present in tobacco, which causes the release of dopamine in different regions of the brain. Recent studies have shown that astrocytes express nicotinic acetylcholine receptors (nAChRs) and mediate calcium signaling. In this study, we examine the morphological and functional adaptations of astrocytes due to nicotine exposure. Utilizing a combination of fluorescence and atomic force microscopy, we show that nicotine-treated astrocytes exhibit time-dependent remodeling in the number and length of both proximal and fine processes. Blocking nAChR activity with an antagonist completely abolishes nicotine's influence on astrocyte morphology indicating that nicotine's action is mediated by these receptors. Functional studies show that 24-hr nicotine treatment induces higher levels of calcium activity in both the cell soma and the processes with a more substantial change observed in the processes. Nicotine does not induce reactive astrocytosis even at high concentrations (10 μM) as determined by cytokine release and glial fibrillary acidic protein expression. We designed tissue clearing experiments to test whether morphological changes occur in vivo using astrocyte specific Aldh1l1-tdTomato knock in mice. We find that nicotine induces a change in the volume of astrocytes in the prefrontal cortex, CA1 of the hippocampus, and the substantia nigra. These results indicate that nicotine directly alters the functional and morphological properties of astrocytes potentially contributing to the underlying mechanism of nicotine abuse.
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Affiliation(s)
- Surya P Aryal
- Department of Chemistry, University of Kentucky, Lexington, Kentucky, USA
| | - Xu Fu
- Department of Chemistry, University of Kentucky, Lexington, Kentucky, USA
| | - Joree N Sandin
- Department of Mechanical Engineering, University of Kentucky, Lexington, Kentucky, USA
| | - Khaga R Neupane
- Department of Chemistry, University of Kentucky, Lexington, Kentucky, USA
| | - Jourdan E Lakes
- Department of Chemistry, University of Kentucky, Lexington, Kentucky, USA
| | - Martha E Grady
- Department of Mechanical Engineering, University of Kentucky, Lexington, Kentucky, USA
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76
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Alcoreza OB, Patel DC, Tewari BP, Sontheimer H. Dysregulation of Ambient Glutamate and Glutamate Receptors in Epilepsy: An Astrocytic Perspective. Front Neurol 2021; 12:652159. [PMID: 33828523 PMCID: PMC8019783 DOI: 10.3389/fneur.2021.652159] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Accepted: 02/24/2021] [Indexed: 12/16/2022] Open
Abstract
Given the important functions that glutamate serves in excitatory neurotransmission, understanding the regulation of glutamate in physiological and pathological states is critical to devising novel therapies to treat epilepsy. Exclusive expression of pyruvate carboxylase and glutamine synthetase in astrocytes positions astrocytes as essential regulators of glutamate in the central nervous system (CNS). Additionally, astrocytes can significantly alter the volume of the extracellular space (ECS) in the CNS due to their expression of the bi-directional water channel, aquaporin-4, which are enriched at perivascular endfeet. Rapid ECS shrinkage has been observed following epileptiform activity and can inherently concentrate ions and neurotransmitters including glutamate. This review highlights our emerging knowledge on the various potential contributions of astrocytes to epilepsy, particularly supporting the notion that astrocytes may be involved in seizure initiation via failure of homeostatic responses that lead to increased ambient glutamate. We also review the mechanisms whereby ambient glutamate can influence neuronal excitability, including via generation of the glutamate receptor subunit GluN2B-mediated slow inward currents, as well as indirectly affect neuronal excitability via actions on metabotropic glutamate receptors that can potentiate GluN2B currents and influence neuronal glutamate release probabilities. Additionally, we discuss evidence for upregulation of System x c - , a cystine/glutamate antiporter expressed on astrocytes, in epileptic tissue and changes in expression patterns of glutamate receptors.
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Affiliation(s)
- Oscar B Alcoreza
- Glial Biology in Health, Disease, and Cancer Center, Fralin Biomedical Research Institute, Virginia Tech Carilion, Roanoke, VA, United States.,School of Medicine, Virginia Tech Carilion, Roanoke, VA, United States.,Translational Biology, Medicine and Health, Virginia Tech, Blacksburg, VA, United States
| | - Dipan C Patel
- Glial Biology in Health, Disease, and Cancer Center, Fralin Biomedical Research Institute, Virginia Tech Carilion, Roanoke, VA, United States
| | - Bhanu P Tewari
- Glial Biology in Health, Disease, and Cancer Center, Fralin Biomedical Research Institute, Virginia Tech Carilion, Roanoke, VA, United States
| | - Harald Sontheimer
- Glial Biology in Health, Disease, and Cancer Center, Fralin Biomedical Research Institute, Virginia Tech Carilion, Roanoke, VA, United States
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77
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Sipe GO, Petravicz J, Rikhye RV, Garcia R, Mellios N, Sur M. Astrocyte glutamate uptake coordinates experience-dependent, eye-specific refinement in developing visual cortex. Glia 2021; 69:1723-1735. [PMID: 33675674 DOI: 10.1002/glia.23987] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Revised: 02/17/2021] [Accepted: 02/24/2021] [Indexed: 12/25/2022]
Abstract
The uptake of glutamate by astrocytes actively shapes synaptic transmission, however its role in the development and plasticity of neuronal circuits remains poorly understood. The astrocytic glutamate transporter, GLT1 is the predominant source of glutamate clearance in the adult mouse cortex. Here, we examined the structural and functional development of the visual cortex in GLT1 heterozygous (HET) mice using two-photon microscopy, immunohistochemistry and slice electrophysiology. We find that though eye-specific thalamic axonal segregation is intact, binocular refinement in the primary visual cortex is disrupted. Eye-specific responses to visual stimuli in GLT1 HET mice show altered binocular matching, with abnormally high responses to ipsilateral compared to contralateral eye stimulation and a greater mismatch between preferred orientation selectivity of ipsilateral and contralateral eye responses. Furthermore, we observe an increase in dendritic spine density in the basal dendrites of layer 2/3 excitatory neurons suggesting aberrant spine pruning. Monocular deprivation induces atypical ocular dominance plasticity in GLT1 HET mice, with an unusual depression of ipsilateral open eye responses; however, this change in ipsilateral responses correlates well with an upregulation of GLT1 protein following monocular deprivation. These results demonstrate that a key function of astrocytic GLT1 function during development is the experience-dependent refinement of ipsilateral eye inputs relative to contralateral eye inputs in visual cortex.
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Affiliation(s)
- Grayson O Sipe
- Department of Brain and Cognitive Sciences, Picower Institute of Learning and Memory, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - Jeremy Petravicz
- Department of Brain and Cognitive Sciences, Picower Institute of Learning and Memory, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - Rajeev V Rikhye
- Department of Brain and Cognitive Sciences, Picower Institute of Learning and Memory, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - Rodrigo Garcia
- Department of Brain and Cognitive Sciences, Picower Institute of Learning and Memory, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - Nikolaos Mellios
- Department of Neurosciences, University of New Mexico School of Medicine, Albuquerque, New Mexico, USA.,Autophagy Inflammation and Metabolism (AIM) Center, Albuquerque, New Mexico, USA
| | - Mriganka Sur
- Department of Brain and Cognitive Sciences, Picower Institute of Learning and Memory, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
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78
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Glial cell type-specific gene expression in the mouse cerebrum using the piggyBac system and in utero electroporation. Sci Rep 2021; 11:4864. [PMID: 33649472 PMCID: PMC7921133 DOI: 10.1038/s41598-021-84210-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2020] [Accepted: 01/25/2021] [Indexed: 12/12/2022] Open
Abstract
Glial cells such as astrocytes and oligodendrocytes play crucial roles in the central nervous system. To investigate the molecular mechanisms underlying the development and the biological functions of glial cells, simple and rapid techniques for glial cell-specific genetic manipulation in the mouse cerebrum would be valuable. Here we uncovered that the Gfa2 promoter is suitable for selective gene expression in astrocytes when used with the piggyBac system and in utero electroporation. In contrast, the Blbp promoter, which has been used to induce astrocyte-specific gene expression in transgenic mice, did not result in astrocyte-specific gene expression. We also identified the Plp1 and Mbp promoters could be used with the piggyBac system and in utero electroporation to induce selective gene expression in oligodendrocytes. Furthermore, using our technique, neuron-astrocyte or neuron-oligodendrocyte interactions can be visualized by labeling neurons, astrocytes and oligodendrocytes differentially. Our study provides a fundamental basis for specific transgene expression in astrocytes and/or oligodendrocytes in the mouse cerebrum.
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79
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Chakraborty R, Vijay Kumar MJ, Clement JP. Critical aspects of neurodevelopment. Neurobiol Learn Mem 2021; 180:107415. [PMID: 33647449 DOI: 10.1016/j.nlm.2021.107415] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Revised: 12/21/2020] [Accepted: 02/16/2021] [Indexed: 12/16/2022]
Abstract
Organisms have the unique ability to adapt to their environment by making use of external inputs. In the process, the brain is shaped by experiences that go hand-in-hand with optimisation of neural circuits. As such, there exists a time window for the development of different brain regions, each unique for a particular sensory modality, wherein the propensity of forming strong, irreversible connections are high, referred to as a critical period of development. Over the years, this domain of neurodevelopmental research has garnered considerable attention from many scientists, primarily because of the intensive activity-dependent nature of development. This review discusses the cellular, molecular, and neurophysiological bases of critical periods of different sensory modalities, and the disorders associated in cases the regulators of development are dysfunctional. Eventually, the neurobiological bases of the behavioural abnormalities related to developmental pathologies are discussed. A more in-depth insight into the development of the brain during the critical period of plasticity will eventually aid in developing potential therapeutics for several neurodevelopmental disorders that are categorised under critical period disorders.
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Affiliation(s)
- Ranabir Chakraborty
- Neuroscience Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bengaluru. Karnataka. India
| | - M J Vijay Kumar
- Neuroscience Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bengaluru. Karnataka. India
| | - James P Clement
- Neuroscience Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bengaluru. Karnataka. India.
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80
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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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81
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Cortical astrocytes regulate ethanol consumption and intoxication in mice. Neuropsychopharmacology 2021; 46:500-508. [PMID: 32464636 PMCID: PMC8027025 DOI: 10.1038/s41386-020-0721-0] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/17/2019] [Revised: 04/30/2020] [Accepted: 05/04/2020] [Indexed: 12/18/2022]
Abstract
Astrocytes are fundamental building blocks of the central nervous system. Their dysfunction has been implicated in many psychiatric disorders, including alcohol use disorder, yet our understanding of their functional role in ethanol intoxication and consumption is very limited. Astrocytes regulate behavior through multiple intracellular signaling pathways, including G-protein coupled-receptor (GPCR)-mediated calcium signals. To test the hypothesis that GPCR-induced calcium signaling is also involved in the behavioral effects of ethanol, we expressed astrocyte-specific excitatory DREADDs in the prefrontal cortex (PFC) of mice. Activating Gq-GPCR signaling in PFC astrocytes increased drinking in ethanol-naïve mice, but not in mice with a history of ethanol drinking. In contrast, reducing calcium signaling with an astrocyte-specific calcium extruder reduced ethanol intake. Cortical astrocyte calcium signaling also altered the acute stimulatory and sedative-hypnotic effects of ethanol. Astrocyte-specific Gq-DREADD activation increased both the locomotor-activating effects of low dose ethanol and the sedative-hypnotic effects of a high dose, while reduced astrocyte calcium signaling diminished sensitivity to the hypnotic effects. In addition, we found that adenosine A1 receptors were required for astrocyte calcium activation to increase ethanol sedation. These results support integral roles for PFC astrocytes in the behavioral actions of ethanol that are due, at least in part, to adenosine receptor activation.
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82
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Aboufares El Alaoui A, Jackson M, Fabri M, de Vivo L, Bellesi M. Characterization of Subcellular Organelles in Cortical Perisynaptic Astrocytes. Front Cell Neurosci 2021; 14:573944. [PMID: 33633542 PMCID: PMC7901967 DOI: 10.3389/fncel.2020.573944] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Accepted: 12/30/2020] [Indexed: 01/18/2023] Open
Abstract
Perisynaptic astrocytic processes (PAPs) carry out several different functions, from metabolite clearing to control of neuronal excitability and synaptic plasticity. All these functions are likely orchestrated by complex cellular machinery that resides within the PAPs and relies on a fine interplay between multiple subcellular components. However, traditional transmission electron microscopy (EM) studies have found that PAPs are remarkably poor of intracellular organelles, failing to explain how such a variety of PAP functions are achieved in the absence of a proportional complex network of intracellular structures. Here, we use serial block-face scanning EM to reconstruct and describe in three dimensions PAPs and their intracellular organelles in two different mouse cortical regions. We described five distinct organelles, which included empty and full endosomes, phagosomes, mitochondria, and endoplasmic reticulum (ER) cisternae, distributed within three PAPs categories (branches, branchlets, and leaflets). The majority of PAPs belonged to the leaflets category (~60%), with branchlets representing a minority (~37%). Branches were rarely in contact with synapses (<3%). Branches had a higher density of mitochondria and ER cisternae than branchlets and leaflets. Also, branches and branchlets displayed organelles more frequently than leaflets. Endosomes and phagosomes, which accounted for more than 60% of all the organelles detected, were often associated with the same PAP. Likewise, mitochondria and ER cisternae, representing ~40% of all organelles were usually associated. No differences were noted between the organelle distribution of the somatosensory and the anterior cingulate cortex. Finally, the organelle distribution in PAPs did not largely depend on the presence of a spine apparatus or a pre-synaptic mitochondrion in the synapse that PAPs were enwrapping, with some exceptions regarding the presence of phagosomes and ER cisternae, which were slightly more represented around synapses lacking a spine apparatus and a presynaptic mitochondrion, respectively. Thus, PAPs contain several subcellular organelles that could underlie the diverse astrocytic functions carried out at central synapses.
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Affiliation(s)
- Amina Aboufares El Alaoui
- Department of Experimental and Clinical Medicine, Marche Polytechnic University, Ancona, Italy.,School of Physiology, Pharmacology, and Neuroscience, University of Bristol, Bristol, United Kingdom
| | - Molly Jackson
- School of Physiology, Pharmacology, and Neuroscience, University of Bristol, Bristol, United Kingdom
| | - Mara Fabri
- Department of Experimental and Clinical Medicine, Marche Polytechnic University, Ancona, Italy
| | - Luisa de Vivo
- School of Physiology, Pharmacology, and Neuroscience, University of Bristol, Bristol, United Kingdom
| | - Michele Bellesi
- School of Physiology, Pharmacology, and Neuroscience, University of Bristol, Bristol, United Kingdom
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83
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Romeo R, Glotzbach K, Scheller A, Faissner A. Deletion of LRP1 From Astrocytes Modifies Neuronal Network Activity in an in vitro Model of the Tripartite Synapse. Front Cell Neurosci 2021; 14:567253. [PMID: 33519378 PMCID: PMC7842215 DOI: 10.3389/fncel.2020.567253] [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] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Accepted: 11/30/2020] [Indexed: 12/30/2022] Open
Abstract
The low-density lipoprotein receptor-related protein 1 (LRP1) is a transmembrane receptor that binds over 40 potential ligands and is involved in processes such as cell differentiation, proliferation, and survival. LRP1 is ubiquitously expressed in the organism and enriched among others in blood vessels, liver, and the central nervous system (CNS). There, it is strongly expressed by neurons, microglia, immature oligodendrocytes, and astrocytes. The constitutive LRP1 knockout leads to embryonic lethality. Therefore, previous studies focused on conditional LRP1-knockout strategies and revealed that the deletion of LRP1 causes an increased differentiation of neural stem and precursor cells into astrocytes. Furthermore, astrocytic LRP1 is necessary for the degradation of Aβ and the reduced accumulation of amyloid plaques in Alzheimer’s disease. Although the role of LRP1 in neurons has intensely been investigated, the function of LRP1 with regard to the differentiation and maturation of astrocytes and their functionality is still unknown. To address this question, we generated an inducible conditional transgenic mouse model, where LRP1 is specifically deleted from GLAST-positive astrocyte precursor cells. The recombination with resulting knockout events was visualized by the simultaneous expression of the fluorescent reporter tdTomato. We observed a significantly increased number of GLT-1 expressing astrocytes in LRP1-depleted astrocytic cultures in comparison to control astrocytes. Furthermore, we investigated the influence of astrocytic LRP1 on neuronal activity and synaptogenesis using the co-culture of hippocampal neurons with control or LRP1-depleted astrocytes. These analyses revealed that the LRP1-deficient astrocytes caused a decreased number of single action potentials as well as a negatively influenced neuronal network activity. Moreover, the proportion of pre- and postsynaptic structures was significantly altered in neurons co-cultured with LPR1-depleted astrocytes. However, the number of structural synapses was not affected. Additionally, the supernatant of hippocampal neurons co-cultured with LRP1-deficient astrocytes showed an altered set of cytokines in comparison to the control condition, which potentially contributed to the altered neuronal transmission and synaptogenesis. Our results suggest astrocytic LRP1 as a modulator of synaptic transmission and synaptogenesis by altering the expression of the glutamate transporter on the cell surface on astrocytes and the release of cytokines in vitro.
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Affiliation(s)
- Ramona Romeo
- Department of Cell Morphology and Molecular Neurobiology, Ruhr-University Bochum, Bochum, Germany
| | - Kristin Glotzbach
- Department of Cell Morphology and Molecular Neurobiology, Ruhr-University Bochum, Bochum, Germany
| | - Anja Scheller
- Department of Molecular Physiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), University of Saarland, Homburg, Germany
| | - Andreas Faissner
- Department of Cell Morphology and Molecular Neurobiology, Ruhr-University Bochum, Bochum, Germany
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84
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Briel N, Pratsch K, Roeber S, Arzberger T, Herms J. Contribution of the astrocytic tau pathology to synapse loss in progressive supranuclear palsy and corticobasal degeneration. Brain Pathol 2020; 31:e12914. [PMID: 33089580 PMCID: PMC8412068 DOI: 10.1111/bpa.12914] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Accepted: 10/12/2020] [Indexed: 12/15/2022] Open
Abstract
Primary 4‐repeat tauopathies with frontotemporal lobar degeneration (FTLD) like Progressive Supranuclear Palsy (PSP) or Corticobasal Degeneration (CBD) show diverse cellular pathology in various brain regions. Besides shared characteristics of neuronal and oligodendroglial cytoplasmic inclusions of accumulated hyperphosphorylated tau protein (pTau), astrocytes in PSP and CBD contain pathognomonic pTau aggregates — hence, lending the designation tufted astrocytes (TA) or astrocytic plaques (AP), respectively. pTau toxicity is most commonly assigned to neurons, whereas the implications of astrocytic pTau for maintaining neurotransmission within the tripartite synapse of human brains is not well understood. We performed immunofluorescent synapse labeling and automated puncta quantification in the medial frontal gyrus (MFG) and striatal regions from PSP and CBD postmortem samples to capture morphometric synaptic alterations. This approach indicated general synaptic losses of both, excitatory and inhibitory bipartite synapses in the frontal cortex of PSP cases, whereas in CBD lower synapse densities were only related to astrocytic plaques. In contrast to tufted astrocytes in PSP, affected astrocytes in CBD could not preserve synaptic integrity within their spatial domains, when compared to non‐affected internal astrocytes or astrocytes in healthy controls. These findings suggest a pTau pathology‐associated role of astrocytes in maintaining connections within neuronal circuits, considered as the microscopic substrate of cognitive dysfunction in CBD. By contrasting astrocytic‐synaptic associations in both diseases, we hereby highlight astrocytic pTau as an important subject of prospective research and as a potential cellular target for therapeutic approaches in the primary tauopathies PSP and CBD.
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Affiliation(s)
- Nils Briel
- German Center for Neurodegenerative Diseases (DZNE) e.V., Site Munich, Munich, Germany.,Center for Neuropathology and Prion Research, University Hospital Munich, Ludwig-Maximilians-University, Munich, Germany.,Munich Medical Research School, Faculty of Medicine, Ludwig-Maximilians-University, Munich, Germany
| | - Katrin Pratsch
- German Center for Neurodegenerative Diseases (DZNE) e.V., Site Munich, Munich, Germany.,Center for Neuropathology and Prion Research, University Hospital Munich, Ludwig-Maximilians-University, Munich, Germany
| | - Sigrun Roeber
- Center for Neuropathology and Prion Research, University Hospital Munich, Ludwig-Maximilians-University, Munich, Germany
| | - Thomas Arzberger
- German Center for Neurodegenerative Diseases (DZNE) e.V., Site Munich, Munich, Germany.,Center for Neuropathology and Prion Research, University Hospital Munich, Ludwig-Maximilians-University, Munich, Germany.,Department of Psychiatry and Psychotherapy, University Hospital Munich, Ludwig-Maximilians-University, Munich, Germany
| | - Jochen Herms
- German Center for Neurodegenerative Diseases (DZNE) e.V., Site Munich, Munich, Germany.,Center for Neuropathology and Prion Research, University Hospital Munich, Ludwig-Maximilians-University, Munich, Germany.,Munich Cluster of Systems Neurology (SyNergy), Ludwig-Maximilians-University, Munich, Germany
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85
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Clarke D, Beros J, Bates KA, Harvey AR, Tang AD, Rodger J. Low intensity repetitive magnetic stimulation reduces expression of genes related to inflammation and calcium signalling in cultured mouse cortical astrocytes. Brain Stimul 2020; 14:183-191. [PMID: 33359601 DOI: 10.1016/j.brs.2020.12.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 12/17/2020] [Accepted: 12/18/2020] [Indexed: 12/26/2022] Open
Abstract
Repetitive transcranial magnetic stimulation (rTMS) is a form of non-invasive brain stimulation frequently used to induce neuroplasticity in the brain. Even at low intensities, rTMS has been shown to modulate aspects of neuronal plasticity such as motor learning and structural reorganisation of neural tissue. However, the impact of low intensity rTMS on glial cells such as astrocytes remains largely unknown. This study investigated changes in RNA (qPCR array: 125 selected genes) and protein levels (immunofluorescence) in cultured mouse astrocytes following a single session of low intensity repetitive magnetic stimulation (LI-rMS - 18 mT). Purified neonatal cortical astrocyte cultures were stimulated with either 1Hz (600 pulses), 10Hz (600 or 6000 pulses) or sham (0 pulses) LI-rMS, followed by RNA extraction at 5 h post-stimulation, or fixation at either 5 or 24-h post-stimulation. LI-rMS resulted in a two-to-four-fold downregulation of mRNA transcripts related to calcium signalling (Stim1 and Orai3), inflammatory molecules (Icam1) and neural plasticity (Ncam1). 10Hz reduced expression of Stim1, Orai3, Kcnmb4, and Ncam1 mRNA, whereas 1Hz reduced expression of Icam1 mRNA and signalling-related genes. Protein levels followed a similar pattern for 10Hz rMS, with a significant reduction of STIM1, ORAI3, KCNMB4, and NCAM1 protein compared to sham, but 1Hz increased STIM1 and ORAI3 protein levels relative to sham. These findings demonstrate the ability of 1Hz and 10Hz LI-rMS to modulate specific aspects of astrocytic phenotype, potentially contributing to the known effects of low intensity rTMS on excitability and neuroplasticity.
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Affiliation(s)
- Darren Clarke
- Experimental and Regenerative Neuroscience, School of Biological Sciences, The University of Western Australia, Nedlands, WA, 6009, Australia; Perron Institute for Neurological and Translational Science, Nedlands, WA, 6009, Australia.
| | - Jamie Beros
- Experimental and Regenerative Neuroscience, School of Biological Sciences, The University of Western Australia, Nedlands, WA, 6009, Australia; Perron Institute for Neurological and Translational Science, Nedlands, WA, 6009, Australia
| | - Kristyn A Bates
- Experimental and Regenerative Neuroscience, School of Biological Sciences, The University of Western Australia, Nedlands, WA, 6009, Australia
| | - Alan R Harvey
- Perron Institute for Neurological and Translational Science, Nedlands, WA, 6009, Australia; School of Human Sciences, The University of Western Australia, Nedlands, WA, 6009, Australia
| | - Alexander D Tang
- Experimental and Regenerative Neuroscience, School of Biological Sciences, The University of Western Australia, Nedlands, WA, 6009, Australia; Perron Institute for Neurological and Translational Science, Nedlands, WA, 6009, Australia
| | - Jennifer Rodger
- Experimental and Regenerative Neuroscience, School of Biological Sciences, The University of Western Australia, Nedlands, WA, 6009, Australia; Perron Institute for Neurological and Translational Science, Nedlands, WA, 6009, Australia
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86
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Smedlund KB, Hill JW. The role of non-neuronal cells in hypogonadotropic hypogonadism. Mol Cell Endocrinol 2020; 518:110996. [PMID: 32860862 DOI: 10.1016/j.mce.2020.110996] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Revised: 08/01/2020] [Accepted: 08/16/2020] [Indexed: 12/18/2022]
Abstract
The hypothalamic-pituitary-gonadal axis is controlled by gonadotropin-releasing hormone (GnRH) released by the hypothalamus. Disruption of this system leads to impaired reproductive maturation and function, a condition known as hypogonadotropic hypogonadism (HH). Most studies to date have focused on genetic causes of HH that impact neuronal development and function. However, variants may also impact the functioning of non-neuronal cells known as glia. Glial cells make up 50% of brain cells of humans, primates, and rodents. They include radial glial cells, microglia, astrocytes, tanycytes, oligodendrocytes, and oligodendrocyte precursor cells. Many of these cells influence the hypothalamic neuroendocrine system controlling fertility. Indeed, glia regulate GnRH neuronal activity and secretion, acting both at their cell bodies and their nerve endings. Recent work has also made clear that these interactions are an essential aspect of how the HPG axis integrates endocrine, metabolic, and environmental signals to control fertility. Recognition of the clinical importance of interactions between glia and the GnRH network may pave the way for the development of new treatment strategies for dysfunctions of puberty and adult fertility.
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Affiliation(s)
- Kathryn B Smedlund
- Department of Physiology and Pharmacology, College of Medicine and Life Sciences, The University of Toledo, Toledo, OH, 43614, USA; Center for Diabetes and Endocrine Research, College of Medicine and Life Sciences, The University of Toledo, Toledo, OH, 43614, USA
| | - Jennifer W Hill
- Department of Physiology and Pharmacology, College of Medicine and Life Sciences, The University of Toledo, Toledo, OH, 43614, USA; Center for Diabetes and Endocrine Research, College of Medicine and Life Sciences, The University of Toledo, Toledo, OH, 43614, USA.
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87
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Takano T, Wallace JT, Baldwin KT, Purkey AM, Uezu A, Courtland JL, Soderblom EJ, Shimogori T, Maness PF, Eroglu C, Soderling SH. Chemico-genetic discovery of astrocytic control of inhibition in vivo. Nature 2020; 588:296-302. [PMID: 33177716 PMCID: PMC8011649 DOI: 10.1038/s41586-020-2926-0] [Citation(s) in RCA: 107] [Impact Index Per Article: 26.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Accepted: 08/19/2020] [Indexed: 01/06/2023]
Abstract
Perisynaptic astrocytic processes are an integral part of central nervous system synapses1,2; however, the molecular mechanisms that govern astrocyte-synapse adhesions and how astrocyte contacts control synapse formation and function are largely unknown. Here we use an in vivo chemico-genetic approach that applies a cell-surface fragment complementation strategy, Split-TurboID, and identify a proteome that is enriched at astrocyte-neuron junctions in vivo, which includes neuronal cell adhesion molecule (NRCAM). We find that NRCAM is expressed in cortical astrocytes, localizes to perisynaptic contacts and is required to restrict neuropil infiltration by astrocytic processes. Furthermore, we show that astrocytic NRCAM interacts transcellularly with neuronal NRCAM coupled to gephyrin at inhibitory postsynapses. Depletion of astrocytic NRCAM reduces numbers of inhibitory synapses without altering glutamatergic synaptic density. Moreover, loss of astrocytic NRCAM markedly decreases inhibitory synaptic function, with minor effects on excitation. Thus, our results present a proteomic framework for how astrocytes interface with neurons and reveal how astrocytes control GABAergic synapse formation and function.
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Affiliation(s)
- Tetsuya Takano
- The Department of Cell Biology, Duke University Medical School, Durham, NC, USA.
| | - John T Wallace
- The Department of Cell Biology, Duke University Medical School, Durham, NC, USA
| | - Katherine T Baldwin
- The Department of Cell Biology, Duke University Medical School, Durham, NC, USA
| | - Alicia M Purkey
- The Department of Cell Biology, Duke University Medical School, Durham, NC, USA
| | - Akiyoshi Uezu
- The Department of Cell Biology, Duke University Medical School, Durham, NC, USA
| | - Jamie L Courtland
- Department of Neurobiology, Duke University Medical School, Durham, NC, USA
| | - Erik J Soderblom
- The Department of Cell Biology, Duke University Medical School, Durham, NC, USA.,Duke Proteomics and Metabolomics Shared Resource and Duke Center for Genomic and Computational Biology, Duke University Medical School, Durham, NC, USA
| | - Tomomi Shimogori
- Molecular Mechanisms of Brain Development, Center for Brain Science (CBS), RIKEN, Saitama, Japan
| | - Patricia F Maness
- Department of Biochemistry, University of North Carolina School of Medicine, Chapel Hill, NC, USA.,Department of Biophysics, University of North Carolina School of Medicine, Chapel Hill, NC, USA
| | - Cagla Eroglu
- The Department of Cell Biology, Duke University Medical School, Durham, NC, USA. .,Department of Neurobiology, Duke University Medical School, Durham, NC, USA.
| | - Scott H Soderling
- The Department of Cell Biology, Duke University Medical School, Durham, NC, USA. .,Department of Neurobiology, Duke University Medical School, Durham, NC, USA.
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88
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Yakoubi R, Rollenhagen A, von Lehe M, Shao Y, Sätzler K, Lübke JHR. Quantitative Three-Dimensional Reconstructions of Excitatory Synaptic Boutons in Layer 5 of the Adult Human Temporal Lobe Neocortex: A Fine-Scale Electron Microscopic Analysis. Cereb Cortex 2020; 29:2797-2814. [PMID: 29931200 DOI: 10.1093/cercor/bhy146] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Revised: 05/22/2018] [Accepted: 05/29/2018] [Indexed: 11/14/2022] Open
Abstract
Studies of synapses are available for different brain regions of several animal species including non-human primates, but comparatively little is known about their quantitative morphology in humans. Here, synaptic boutons in Layer 5 (L5) of the human temporal lobe (TL) neocortex were investigated in biopsy tissue, using fine-scale electron microscopy, and quantitative three-dimensional reconstructions. The size and organization of the presynaptic active zones (PreAZs), postsynaptic densities (PSDs), and that of the 3 distinct pools of synaptic vesicles (SVs) were particularly analyzed. L5 synaptic boutons were medium-sized (~6 μm2) with a single but relatively large PreAZ (~0.3 μm2). They contained a total of ~1500 SVs/bouton, ~20 constituting the putative readily releasable pool (RRP), ~180 the recycling pool (RP), and the remainder, the resting pool. The PreAZs, PSDs, and vesicle pools are ~3-fold larger than those of CNS synapses in other species. Astrocytic processes reached the synaptic cleft and may regulate the glutamate concentration. Profound differences exist between synapses in human TL neocortex and those described in various species, particularly in the size and geometry of PreAZs and PSDs, the large RRP/RP, and the astrocytic ensheathment suggesting high synaptic efficacy, strength, and modulation of synaptic transmission at human synapses.
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Affiliation(s)
- Rachida Yakoubi
- Institute of Neuroscience and Medicine INM-10, Research Centre Jülich GmbH, Leo-Brandt Str., Jülich, Germany
| | - Astrid Rollenhagen
- Institute of Neuroscience and Medicine INM-10, Research Centre Jülich GmbH, Leo-Brandt Str., Jülich, Germany
| | - Marec von Lehe
- University Hospital/Knappschaftskrankenhaus Bochum, In der Schornau 23-25, Bochum, Germany.,Department of Neurosurgery, Ruppiner Kliniken, Medizinische Hochschule Brandenburg, Fehrbelliner Str. 38, Neuruppin, Germany
| | - Yachao Shao
- Simulation Lab Neuroscience, Research Centre Jülich GmbH, Leo-Brandt Str., Jülich, Germany.,College of Computer, National University of Defense Technology, Changsha, China
| | - Kurt Sätzler
- School of Biomedical Sciences, University of Ulster, Cromore Rd., BT52 1SA, Londonderry, UK
| | - Joachim H R Lübke
- Institute of Neuroscience and Medicine INM-10, Research Centre Jülich GmbH, Leo-Brandt Str., Jülich, Germany.,Department of Psychiatry, Psychotherapy and Psychosomatics, Medical Faculty/RWTH University Hospital Aachen, Pauwelsstr. 30, Aachen, Germany.,JARA Translational Brain Medicine, Germany
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89
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Paracrine Role for Somatostatin Interneurons in the Assembly of Perisomatic Inhibitory Synapses. J Neurosci 2020; 40:7421-7435. [PMID: 32847968 DOI: 10.1523/jneurosci.0613-20.2020] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Revised: 07/24/2020] [Accepted: 08/18/2020] [Indexed: 12/13/2022] Open
Abstract
GABAergic interneurons represent a heterogenous group of cell types in neocortex that can be clustered based on developmental origin, morphology, physiology, and connectivity. Two abundant populations of cortical GABAergic interneurons include the low-threshold, somatostatin (SST)-expressing cells and the fast-spiking, parvalbumin (PV)-expressing cells. While SST+ and PV+ interneurons are both early born and migrate into the developing neocortex at similar times, SST+ cells are incorporated into functional circuits prior to PV+ cells. During this early period of neural development, SST+ cells play critical roles in the assembly and maturation of other cortical circuits; however, the mechanisms underlying this process remain poorly understood. Here, using both sexes of conditional mutant mice, we discovered that SST+ interneuron-derived Collagen XIX, a synaptogenic extracellular matrix protein, is required for the formation of GABAergic, perisomatic synapses by PV+ cells. These results, therefore, identify a paracrine mechanism by which early-born SST+ cells orchestrate inhibitory circuit formation in the developing neocortex.SIGNIFICANCE STATEMENT Inhibitory interneurons in the cerebral cortex represent a heterogenous group of cells that generate the inhibitory neurotransmitter GABA. One such interneuron type is the low-threshold, somatostatin (SST)-expressing cell, which is one of the first types of interneurons to migrate into the cerebral cortex and become incorporated into functional circuits. In addition, to contributing important roles in controlling the flow of information in the adult cerebral cortex, SST+ cells play important roles in the development of other neural circuits in the developing brain. Here, we identified an extracellular matrix protein that is released by these early-born SST+ neurons to orchestrate inhibitory circuit formation in the developing cerebral cortex.
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90
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In vivo two-photon microscopic observation and ablation in deeper brain regions realized by modifications of excitation beam diameter and immersion liquid. PLoS One 2020; 15:e0237230. [PMID: 32764808 PMCID: PMC7413496 DOI: 10.1371/journal.pone.0237230] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Accepted: 07/21/2020] [Indexed: 02/06/2023] Open
Abstract
In vivo two-photon microscopy utilizing a nonlinear optical process enables, in living mouse brains, not only the visualization of morphologies and functions of neural networks in deep regions but also their optical manipulation at targeted sites with high spatial precision. Because the two-photon excitation efficiency is proportional to the square of the photon density of the excitation laser light at the focal position, optical aberrations induced by specimens mainly limit the maximum depth of observations or that of manipulations in the microscopy. To increase the two-photon excitation efficiency, we developed a method for evaluating the focal volume in living mouse brains. With this method, we modified the beam diameter of the excitation laser light and the value of the refractive index in the immersion liquid to maximize the excitation photon density at the focal position. These two modifications allowed the successful visualization of the finer structures of hippocampal CA1 neurons, as well as the intracellular calcium dynamics in cortical layer V astrocytes, even with our conventional two-photon microscopy system. Furthermore, it enabled focal laser ablation dissection of both single apical and single basal dendrites of cortical layer V pyramidal neurons. These simple modifications would enable us to investigate the contributions of single cells or single dendrites to the functions of local cortical networks.
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91
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Ueno H, Suemitsu S, Murakami S, Kitamura N, Wani K, Takahashi Y, Matsumoto Y, Okamoto M, Ishihara T. Pentylenetetrazol kindling induces cortical astrocytosis and increased expression of extracellular matrix molecules in mice. Brain Res Bull 2020; 163:120-134. [PMID: 32726668 DOI: 10.1016/j.brainresbull.2020.07.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2019] [Revised: 07/13/2020] [Accepted: 07/17/2020] [Indexed: 11/30/2022]
Abstract
Although epilepsy is one of the most common chronic neurological disorders with a prevalence of approximately 1.0 %, the underlying pathophysiology remains to be elucidated. Understanding the molecular and cellular mechanisms involved in the development of epilepsy is important for the development of appropriate therapeutic strategy. In this study, we investigated the effects of status epilepticus on astrocytes, microglia, and extracellular matrix (ECM) molecules in the somatosensory cortex and piriform cortex of mice. Activation of astrocytes was observed in many cortices except the retrosplenial granular cortex after pentylenetetrazol (PTZ)-induced kindling in mice. Activated astrocytes in the cortex were found in layers 1-3 but not in layers 4-6. In the somatosensory and piriform cortices, no change was observed in the number of parvalbumin (PV)-positive neurons and PV-positive neurons covered with perineuronal nets. However, the amount of ECM in the extracellular space increased. The expression of VGLUT1- and GAD67-positive synapses also increased. Thus, in the PTZ-kindling epilepsy mice model, an increase in the number of ECM molecules and activation of astrocytes were observed in the somatosensory cortex and piriform cortex. These results indicate that PTZ-induced seizures affect not only the hippocampus but also other cortical areas. Our study findings may help to develop new therapeutic approaches to prevent seizures or their sequelae.
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Affiliation(s)
- Hiroshi Ueno
- Department of Medical Technology, Kawasaki University of Medical Welfare, Kurashiki, 701-0193, Japan.
| | - Shunsuke Suemitsu
- Department of Psychiatry, Kawasaki Medical School, Kurashiki, 701-0192, Japan.
| | - Shinji Murakami
- Department of Psychiatry, Kawasaki Medical School, Kurashiki, 701-0192, Japan.
| | - Naoya Kitamura
- Department of Psychiatry, Kawasaki Medical School, Kurashiki, 701-0192, Japan.
| | - Kenta Wani
- Department of Psychiatry, Kawasaki Medical School, Kurashiki, 701-0192, Japan.
| | - Yu Takahashi
- Department of Psychiatry, Kawasaki Medical School, Kurashiki, 701-0192, Japan.
| | - Yosuke Matsumoto
- Department of Neuropsychiatry, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, 700-8558, Japan.
| | - Motoi Okamoto
- Department of Medical Technology, Graduate School of Health Sciences, Okayama University, Okayama, 700-8558, Japan.
| | - Takeshi Ishihara
- Department of Psychiatry, Kawasaki Medical School, Kurashiki, 701-0192, Japan.
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92
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Takata-Tsuji F, Chounlamountri N, Do LD, Philippot C, Novion Ducassou J, Couté Y, Ben Achour S, Honnorat J, Place C, Pascual O. Microglia modulate gliotransmission through the regulation of VAMP2 proteins in astrocytes. Glia 2020; 69:61-72. [PMID: 32633839 DOI: 10.1002/glia.23884] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Revised: 06/12/2020] [Accepted: 06/15/2020] [Indexed: 12/31/2022]
Abstract
Vesicular release is one of the release mechanisms of various signaling molecules. In neurons, the molecular machinery involved in vesicular release has been designed through evolution to trigger fast and synchronous release of neurotransmitters. Similar machinery with a slower kinetic and a slightly different molecular assembly allows astrocytes to release various transmitters such as adenosine triphosphate (ATP), glutamate, and D-serine. Astrocytes are important modulators of neurotransmission through gliotransmitter release. We recently demonstrated that microglia, another type of glia, release ATP to modulate synaptic transmission using astrocytes as intermediate. We now report that microglia regulate astrocytic gliotransmission through the regulation of SNARE proteins in astrocytes. Indeed, we found that gliotransmission triggered by P2Y1 agonist is impaired in slices from transgenic mice devoid of microglia. Using total internal reflection fluorescence imaging, we found that the vesicular release of gliotransmitter by astrocytes was different in cultures lacking microglia compared to vesicular release in astrocytes cocultured with microglia. Quantification of the kinetic of vesicular release indicates that the overall release appears to be faster in pure astrocyte cultures with more vesicles close to the membrane when compared to astrocytes cocultured with microglia. Finally, biochemical investigation of SNARE protein expression indicates an upregulation of VAMP2 in absence of microglia. Altogether, these results indicate that microglia seems to be involved in the regulation of an astrocytic phenotype compatible with proper gliotransmission. The mechanisms described in this study could be of importance for central nervous system diseases where microglia are activated.
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Affiliation(s)
- Fuyuko Takata-Tsuji
- INSERM U1217, CNRS UMR5310, Institut NeuroMyoGène, Lyon, France.,Université Claude Bernard Lyon 1 Lyon, Université de Lyon, Lyon, France.,Department of Pharmaceutical Care and Health Sciences, Faculty of Pharmaceutical Sciences, Fukuoka University, Fukuoka, Japan
| | - Naura Chounlamountri
- INSERM U1217, CNRS UMR5310, Institut NeuroMyoGène, Lyon, France.,Université Claude Bernard Lyon 1 Lyon, Université de Lyon, Lyon, France
| | - Le-Duy Do
- INSERM U1217, CNRS UMR5310, Institut NeuroMyoGène, Lyon, France.,Université Claude Bernard Lyon 1 Lyon, Université de Lyon, Lyon, France
| | - Camille Philippot
- INSERM U1217, CNRS UMR5310, Institut NeuroMyoGène, Lyon, France.,Université Claude Bernard Lyon 1 Lyon, Université de Lyon, Lyon, France
| | | | - Yohann Couté
- Université Grenoble Alpes, CEA, INSERM, IRIG, BGE, Grenoble, France
| | - Sarrah Ben Achour
- Institut de Biologie de l'Ecole Normale Supérieure (IBENS), Ecole Normale Supérieure, Université PSL, CNRS, INSERM, Paris, France
| | - Jérôme Honnorat
- INSERM U1217, CNRS UMR5310, Institut NeuroMyoGène, Lyon, France.,Université Claude Bernard Lyon 1 Lyon, Université de Lyon, Lyon, France.,Centre maladies rares sur les syndromes neurologiques paranéoplasiques, hospices Civils de Lyon, Lyon, France
| | - Christophe Place
- ENS de Lyon, CNRS, Laboratoire de Physique, Université de Lyon, Lyon, France
| | - Olivier Pascual
- INSERM U1217, CNRS UMR5310, Institut NeuroMyoGène, Lyon, France.,Université Claude Bernard Lyon 1 Lyon, Université de Lyon, Lyon, France
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93
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Klaft ZJ, Dulla C. Astrocytes Keep It Under Wraps: Reconstructing Synapses in the Latent Phase of Epileptogenesis. Epilepsy Curr 2020; 20:230-232. [PMID: 34025236 PMCID: PMC7427165 DOI: 10.1177/1535759720928377] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
[Box: see text]
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94
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Jackson FR, You S, Crowe LB. Regulation of rhythmic behaviors by astrocytes. WILEY INTERDISCIPLINARY REVIEWS. DEVELOPMENTAL BIOLOGY 2020; 9:e372. [PMID: 31840430 DOI: 10.1002/wdev.372] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Revised: 11/19/2019] [Accepted: 11/28/2019] [Indexed: 12/19/2022]
Abstract
Glial astrocytes of vertebrates and invertebrates are important modulators of nervous system development, physiology, and behavior. In all species examined, astrocytes of the adult brain contain conserved circadian clocks, and multiple studies have shown that these glial cells participate in the regulation of circadian behavior and sleep. This short review summarizes recent work, using fruit fly (Drosophila) and mouse models, that document participation of astrocytes and their endogenous circadian clocks in the control of rhythmic behavior. This article is categorized under: Gene Expression and Transcriptional Hierarchies > Regulatory Mechanisms Nervous System Development > Flies.
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Affiliation(s)
- F Rob Jackson
- Department of Neuroscience, Tufts University School of Medicine, Boston, Massachusetts
| | - Samantha You
- Department of Neuroscience, Tufts University School of Medicine, Boston, Massachusetts
| | - Lauren B Crowe
- Department of Neuroscience, Tufts University School of Medicine, Boston, Massachusetts
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95
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Pinet-Charvet C, Fleurot R, Derouin-Tochon F, de Graaf S, Druart X, Tsikis G, Taragnat C, Teixeira-Gomes AP, Labas V, Moreau T, Cayla X, Duittoz AH. Beta-nerve growth factor stimulates spontaneous electrical activity of in vitro embryonic mouse GnRH neurons through a P75 mediated-mechanism. Sci Rep 2020; 10:10654. [PMID: 32606357 PMCID: PMC7326925 DOI: 10.1038/s41598-020-67665-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Accepted: 06/11/2020] [Indexed: 02/04/2023] Open
Abstract
The control of ovulation helps guarantee the success of reproduction and as such, contributes to the fitness of a species. In mammals, two types of ovulation are observed: induced and spontaneous ovulation. Recent work on camelids, that are induced ovulators, highlighted the role of a factor present in seminal plasma, beta Nerve Growth Factor (β-NGF), as the factor that triggers ovulation in a GnRH dependent manner. In the present work, we characterized alpaca β-NGF (aβ-NGF) and its 3D structure and compared it with human recombinant β-NGF (hβ-NGF). We showed that the β-NGF enriched fraction of alpaca semen and the human recombinant protein, both stimulated spontaneous electrical activity of primary GnRH neurons derived from mouse embryonic olfactory placodes. This effect was dose-dependent and mediated by p75 receptor signaling. P75 receptors were found expressed in vitro by olfactory ensheathing cells (OEC) in close association with GnRH neurons and in vivo by tanycytes in close vicinity to GnRH fibers in adult mouse. Altogether, these results suggested that β-NGF induced ovulation through an increase in GnRH secretion provoked by a glial dependent P75 mediated mechanism.
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Affiliation(s)
- Caroline Pinet-Charvet
- Physiologie de la Reproduction et des Comportements (PRC) UMR7247 INRA, CNRS, Centre INRA Val de Loire, Université de Tours, IFCE, 37380, Nouzilly, France
- Physiologie de la Reproduction et des Comportements (PRC), ComUE Centre-Val de Loire, Centre INRA Val de Loire, Université de Poitiers, 37380, Nouzilly, France
| | - Renaud Fleurot
- Physiologie de la Reproduction et des Comportements (PRC) UMR7247 INRA, CNRS, Centre INRA Val de Loire, Université de Tours, IFCE, 37380, Nouzilly, France
| | - Flavie Derouin-Tochon
- Physiologie de la Reproduction et des Comportements (PRC) UMR7247 INRA, CNRS, Centre INRA Val de Loire, Université de Tours, IFCE, 37380, Nouzilly, France
| | - Simon de Graaf
- Faculty of Science, School of Life and Environmental Sciences, The University of Sydney, Sydney, NSW, 2006, Australia
| | - Xavier Druart
- Physiologie de la Reproduction et des Comportements (PRC) UMR7247 INRA, CNRS, Centre INRA Val de Loire, Université de Tours, IFCE, 37380, Nouzilly, France
| | - Guillaume Tsikis
- Physiologie de la Reproduction et des Comportements (PRC) UMR7247 INRA, CNRS, Centre INRA Val de Loire, Université de Tours, IFCE, 37380, Nouzilly, France
| | - Catherine Taragnat
- Physiologie de la Reproduction et des Comportements (PRC) UMR7247 INRA, CNRS, Centre INRA Val de Loire, Université de Tours, IFCE, 37380, Nouzilly, France
| | - Ana-Paula Teixeira-Gomes
- Infectiologie et Santé Publique (ISP) UMR1282, INRA, Centre INRA Val de Loire, Université de Tours, 37380, Nouzilly, France
| | - Valérie Labas
- Physiologie de la Reproduction et des Comportements (PRC) UMR7247 INRA, CNRS, Centre INRA Val de Loire, Université de Tours, IFCE, 37380, Nouzilly, France
| | - Thierry Moreau
- Biologie des Oiseaux et Aviculture (BOA) UMR Centre INRA Val de Loire, 37380, Nouzilly, France
| | - Xavier Cayla
- Physiologie de la Reproduction et des Comportements (PRC) UMR7247 INRA, CNRS, Centre INRA Val de Loire, Université de Tours, IFCE, 37380, Nouzilly, France
| | - Anne H Duittoz
- Physiologie de la Reproduction et des Comportements (PRC) UMR7247 INRA, CNRS, Centre INRA Val de Loire, Université de Tours, IFCE, 37380, Nouzilly, France.
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96
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Bres EE, Safina D, Müller J, Bedner P, Yang H, Helluy X, Shchyglo O, Jansen S, Mark MD, Esser A, Steinhäuser C, Herlitze S, Pietrzik CU, Sirko S, Manahan-Vaughan D, Faissner A. Lipoprotein receptor loss in forebrain radial glia results in neurological deficits and severe seizures. Glia 2020; 68:2517-2549. [PMID: 32579270 DOI: 10.1002/glia.23869] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Revised: 05/19/2020] [Accepted: 05/22/2020] [Indexed: 02/06/2023]
Abstract
The Alzheimer disease-associated multifunctional low-density lipoprotein receptor-related protein-1 is expressed in the brain. Recent studies uncovered a role of this receptor for the appropriate functioning of neural stem cells, oligodendrocytes, and neurons. The constitutive knock-out (KO) of the receptor is embryonically lethal. To unravel the receptors' role in the developing brain we generated a mouse mutant by specifically targeting radial glia stem cells of the dorsal telencephalon. The low-density lipoprotein receptor-related protein-1 lineage-restricted KO female and male mice, in contrast to available models, developed a severe neurological phenotype with generalized seizures during early postnatal development. The mechanism leading to a buildup of hyperexcitability and emergence of seizures was traced to a failure in adequate astrocyte development and deteriorated postsynaptic density integrity. The detected impairments in the astrocytic lineage: precocious maturation, reactive gliosis, abolished tissue plasminogen activator uptake, and loss of functionality emphasize the importance of this glial cell type for synaptic signaling in the developing brain. Together, the obtained results highlight the relevance of astrocytic low-density lipoprotein receptor-related protein-1 for glutamatergic signaling in the context of neuron-glia interactions and stage this receptor as a contributing factor for epilepsy.
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Affiliation(s)
- Ewa E Bres
- Department of Cell Morphology and Molecular Neurobiology, Ruhr University Bochum, Bochum, Germany.,International Graduate School of Neuroscience, Ruhr University Bochum, Bochum, Germany
| | - Dina Safina
- Department of Cell Morphology and Molecular Neurobiology, Ruhr University Bochum, Bochum, Germany.,International Graduate School of Neuroscience, Ruhr University Bochum, Bochum, Germany
| | - Julia Müller
- Institute of Cellular Neurosciences, Medical Faculty, University of Bonn, Bonn, Germany
| | - Peter Bedner
- Institute of Cellular Neurosciences, Medical Faculty, University of Bonn, Bonn, Germany
| | - Honghong Yang
- Department of Neurophysiology, Medical Faculty, Ruhr University Bochum, Bochum, Germany
| | - Xavier Helluy
- Department of Neurophysiology, Medical Faculty, Ruhr University Bochum, Bochum, Germany.,Department of Psychology, Institute of Cognitive Neuroscience, Biopsychology, Ruhr University Bochum, Bochum, Germany
| | - Olena Shchyglo
- Department of Neurophysiology, Medical Faculty, Ruhr University Bochum, Bochum, Germany
| | - Stephan Jansen
- Department of Neurophysiology, Medical Faculty, Ruhr University Bochum, Bochum, Germany
| | - Melanie D Mark
- Behavioral Neuroscience, Ruhr University Bochum, Bochum, Germany
| | | | - Christian Steinhäuser
- Institute of Cellular Neurosciences, Medical Faculty, University of Bonn, Bonn, Germany
| | - Stefan Herlitze
- Department of General Zoology and Neurobiology, Ruhr University Bochum, Bochum, Germany
| | - Claus U Pietrzik
- Institute of Pathobiochemistry, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany
| | - Swetlana Sirko
- Department of Physiological Genomics, Biomedical Center (BMC), Ludwig-Maximilians University, Planegg-Martinsried, Germany.,Institute for Stem Cell Research, Helmholtz Zentrum Munich, Neuherberg, Germany
| | | | - Andreas Faissner
- Department of Cell Morphology and Molecular Neurobiology, Ruhr University Bochum, Bochum, Germany
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97
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Huang AYS, Woo J, Sardar D, Lozzi B, Bosquez Huerta NA, Lin CCJ, Felice D, Jain A, Paulucci-Holthauzen A, Deneen B. Region-Specific Transcriptional Control of Astrocyte Function Oversees Local Circuit Activities. Neuron 2020; 106:992-1008.e9. [PMID: 32320644 PMCID: PMC7879989 DOI: 10.1016/j.neuron.2020.03.025] [Citation(s) in RCA: 73] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Revised: 02/24/2020] [Accepted: 03/24/2020] [Indexed: 02/06/2023]
Abstract
Astrocytes play essential roles in brain function by supporting synaptic connectivity and associated circuits. How these roles are regulated by transcription factors is unknown. Moreover, there is emerging evidence that astrocytes exhibit regional heterogeneity, and the mechanisms controlling this diversity remain nascent. Here, we show that conditional deletion of the transcription factor nuclear factor I-A (NFIA) in astrocytes in the adult brain results in region-specific alterations in morphology and physiology that are mediated by selective DNA binding. Disruptions in astrocyte function following loss of NFIA are most pronounced in the hippocampus, manifested by impaired interactions with neurons, coupled with diminution of learning and memory behaviors. These changes in hippocampal astrocytes did not affect basal neuronal properties but specifically inhibited synaptic plasticity, which is regulated by NFIA in astrocytes through calcium-dependent mechanisms. Together, our studies reveal region-specific transcriptional dependencies for astrocytes and identify astrocytic NFIA as a key transcriptional regulator of hippocampal circuits.
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Affiliation(s)
- Anna Yu-Szu Huang
- Center for Cell and Gene Therapy, Baylor College of Medicine, Houston, TX 77030, USA; Program in Developmental Biology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Junsung Woo
- Center for Cell and Gene Therapy, Baylor College of Medicine, Houston, TX 77030, USA
| | - Debosmita Sardar
- Center for Cell and Gene Therapy, Baylor College of Medicine, Houston, TX 77030, USA
| | - Brittney Lozzi
- Center for Cell and Gene Therapy, Baylor College of Medicine, Houston, TX 77030, USA
| | - Navish A Bosquez Huerta
- Center for Cell and Gene Therapy, Baylor College of Medicine, Houston, TX 77030, USA; Program in Developmental Biology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Chia-Ching John Lin
- Center for Cell and Gene Therapy, Baylor College of Medicine, Houston, TX 77030, USA
| | - Daniela Felice
- Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA
| | - Antrix Jain
- Mass Spectrometry Proteomics Core, Baylor College of Medicine, Houston, TX 77030, USA
| | | | - Benjamin Deneen
- Center for Cell and Gene Therapy, Baylor College of Medicine, Houston, TX 77030, USA; Program in Developmental Biology, Baylor College of Medicine, Houston, TX 77030, USA; Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA; Department of Neurosurgery, Baylor College of Medicine, Houston, TX 77030, USA.
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98
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Astrocyte Signaling Gates Long-Term Depression at Corticostriatal Synapses of the Direct Pathway. J Neurosci 2020; 40:5757-5768. [PMID: 32541069 DOI: 10.1523/jneurosci.2369-19.2020] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2019] [Revised: 05/04/2020] [Accepted: 05/05/2020] [Indexed: 12/19/2022] Open
Abstract
Despite extensive research into understanding synaptic mechanisms of striatal plasticity, the functional role played by astrocytes in this region remains to be fully elucidated. It was recently demonstrated that high-frequency stimulation (HFS) of cortical inputs induced long-term depression (LTD) mediated by adenosine A1 receptor (A1R) activation at corticostriatal synapses of the direct pathway [cortico-striatal projection neuron (dSPN)] in the dorsolateral striatum (DLS). Because astrocyte-derived adenosine has been shown to regulate synaptic transmission in several brain areas, we investigated whether this form of neuron-astrocyte signaling contributes to synaptic plasticity in the DLS of male and female mice. We found that cortical HFS increases calcium (Ca2+) levels in striatal astrocytes through activation of metabotropic glutamate receptor type 5 (mGluR5) signaling and that this astrocyte-mediated response is necessary for A1R-mediated LTD. Consistent with this, astrocyte activation with Gq designer receptors exclusively activated by designer drugs (DREADDs) induced A1R-mediated synaptic depression at cortico-dSPN synapses. Together, these results indicate that astrocytes are integral elements of striatal A1R-mediated LTD.SIGNIFICANCE STATEMENT Abnormal striatal circuit function is implicated in several disorders such as Parkinson's disease and Huntington's disease. Thus, there is a need to better understand the mechanisms supporting proper striatal activity. While extensive work has revealed the many important contributions from neurons in striatal function, far less is known about the role of astrocytes in this brain area. We show that long-term depression (LTD) at corticostriatal synapses of the direct pathway is not strictly a neuronal phenomenon; astrocytes respond to corticostriatal stimulation and this astrocyte response is necessary for LTD. This research adds to the accumulating evidence that astrocytes are active and integral players in synaptic communication, and that neuron-astrocyte interactions are key cellular processes involved in brain function.
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99
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Structural basis of astrocytic Ca 2+ signals at tripartite synapses. Nat Commun 2020; 11:1906. [PMID: 32312988 PMCID: PMC7170846 DOI: 10.1038/s41467-020-15648-4] [Citation(s) in RCA: 86] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Accepted: 03/19/2020] [Indexed: 02/07/2023] Open
Abstract
Astrocytic Ca2+ signals can be fast and local, supporting the idea that astrocytes have the ability to regulate single synapses. However, the anatomical basis of such specific signaling remains unclear, owing to difficulties in resolving the spongiform domain of astrocytes where most tripartite synapses are located. Using 3D-STED microscopy in living organotypic brain slices, we imaged the spongiform domain of astrocytes and observed a reticular meshwork of nodes and shafts that often formed loop-like structures. These anatomical features were also observed in acute hippocampal slices and in barrel cortex in vivo. The majority of dendritic spines were contacted by nodes and their sizes were correlated. FRAP experiments and Ca2+ imaging showed that nodes were biochemical compartments and Ca2+ microdomains. Mapping astrocytic Ca2+ signals onto STED images of nodes and dendritic spines showed they were associated with individual synapses. Here, we report on the nanoscale organization of astrocytes, identifying nodes as a functional astrocytic component of tripartite synapses that may enable synapse-specific communication between neurons and astrocytes. Astrocytic Ca2+ signals can be fast and local, supporting the idea that astrocytes have the ability to regulate single synapses. Here, the authors report the organization of astrocytes at nanoscale level and identify nodes as a functional astrocytic component of tripartite synapses.
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100
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Kofuji P, Araque A. G-Protein-Coupled Receptors in Astrocyte-Neuron Communication. Neuroscience 2020; 456:71-84. [PMID: 32224231 DOI: 10.1016/j.neuroscience.2020.03.025] [Citation(s) in RCA: 119] [Impact Index Per Article: 29.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Revised: 03/13/2020] [Accepted: 03/18/2020] [Indexed: 12/11/2022]
Abstract
Astrocytes, a major type of glial cell, are known to play key supportive roles in brain function, contributing to ion and neurotransmitter homeostasis, maintaining the blood-brain barrier and providing trophic and metabolic support for neurons. Besides these support functions, astrocytes are emerging as important elements in brain physiology through signaling exchange with neurons at tripartite synapses. Astrocytes express a wide variety of neurotransmitter transporters and receptors that allow them to sense and respond to synaptic activity. Principal among them are the G-protein-coupled receptors (GPCRs) in astrocytes because their activation by synaptically released neurotransmitters leads to mobilization of intracellular calcium. In turn, activated astrocytes release neuroactive substances called gliotransmitters, such as glutamate, GABA, and ATP/adenosine that lead to synaptic regulation through activation of neuronal GPCRs. In this review we will present and discuss recent evidence demonstrating the critical roles played by GPCRs in the bidirectional astrocyte-neuron signaling, and their crucial involvement in the astrocyte-mediated regulation of synaptic transmission and plasticity.
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Affiliation(s)
- Paulo Kofuji
- Department of Neuroscience, University of Minnesota, Minneapolis, MN 55455, USA.
| | - Alfonso Araque
- Department of Neuroscience, University of Minnesota, Minneapolis, MN 55455, USA.
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