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Lowe SA, Wilson AD, Aughey GN, Banerjee A, Goble T, Simon-Batsford N, Sanderson A, Kratschmer P, Balogun M, Gao H, Aw SS, Jepson JEC. Modulation of a critical period for motor development in Drosophila by BK potassium channels. Curr Biol 2024; 34:3488-3505.e3. [PMID: 39053467 DOI: 10.1016/j.cub.2024.06.069] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Revised: 04/16/2024] [Accepted: 06/26/2024] [Indexed: 07/27/2024]
Abstract
Critical periods are windows of heightened plasticity occurring during neurodevelopment. Alterations in neural activity during these periods can cause long-lasting changes in the structure, connectivity, and intrinsic excitability of neurons, which may contribute to the pathology of neurodevelopmental disorders. However, endogenous regulators of critical periods remain poorly defined. Here, we study this issue using a fruit fly (Drosophila) model of an early-onset movement disorder caused by BK potassium channel gain of function (BK GOF). Deploying a genetic method to place robust expression of GOF BK channels under spatiotemporal control, we show that adult-stage neuronal expression of GOF BK channels minimally disrupts fly movement. In contrast, limiting neuronal expression of GOF BK channels to a short window during late neurodevelopment profoundly impairs locomotion and limb kinematics in resulting adult flies. During this critical period, BK GOF perturbs synaptic localization of the active zone protein Bruchpilot and reduces excitatory neurotransmission. Conversely, enhancing neural activity specifically during development rescues motor defects in BK GOF flies. Collectively, our results reveal a critical developmental period for limb control in Drosophila that is influenced by BK channels and suggest that BK GOF causes movement disorders by disrupting activity-dependent aspects of synaptic development.
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Affiliation(s)
- Simon A Lowe
- Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, UK.
| | - Abigail D Wilson
- Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, UK
| | - Gabriel N Aughey
- Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, UK
| | - Animesh Banerjee
- Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology and Research (A(∗)STAR), 61 Biopolis Drive, Proteos, Singapore 138673, Singapore
| | - Talya Goble
- Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, UK; Department of Cell and Developmental Biology, University College London, London, UK
| | - Nell Simon-Batsford
- Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, UK
| | - Angelina Sanderson
- Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, UK; Champalimaud Research, Champalimaud Centre for the Unknown, Lisboa, Portugal
| | - Patrick Kratschmer
- Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, UK
| | - Maryam Balogun
- Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, UK
| | - Hao Gao
- Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, UK
| | - Sherry S Aw
- Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology and Research (A(∗)STAR), 61 Biopolis Drive, Proteos, Singapore 138673, Singapore
| | - James E C Jepson
- Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, UK.
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2
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Odierna GL, Kerwin SK, Shin GJE, Millard SS. Drosophila larval motor patterning relies on regulated alternative splicing of Dscam2. Front Mol Neurosci 2024; 17:1415207. [PMID: 39092203 PMCID: PMC11292952 DOI: 10.3389/fnmol.2024.1415207] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2024] [Accepted: 05/31/2024] [Indexed: 08/04/2024] Open
Abstract
Recent studies capitalizing on the newly complete nanometer-resolution Drosophila larval connectome have made significant advances in identifying the structural basis of motor patterning. However, the molecular mechanisms utilized by neurons to wire these circuits remain poorly understood. In this study we explore how cell-specific expression of two Dscam2 isoforms, which mediate isoform-specific homophilic binding, contributes to motor patterning and output of Drosophila larvae. Ablating Dscam2 isoform diversity resulted in impaired locomotion. Electrophysiological assessment at the neuromuscular junction during fictive locomotion indicated that this behavioral defect was largely caused by weaker bouts of motor neuron activity. Morphological analyses of single motor neurons using MultiColour FlpOut revealed severe errors in dendrite arborization and assessment of cholinergic and GABAergic projections to the motor domain revealed altered morphology of interneuron processes. Loss of Dscam2 did not affect locomotor output, motor neuron activation or dendrite targeting. Our findings thus suggest that locomotor circuit phenotypes arise specifically from inappropriate Dscam2 interactions between premotor interneurons and motor neurons when they express the same isoform. Indeed, we report here that first-order premotor interneurons express Dscam2A. Since motor neurons express Dscam2B, our results provide evidence that Dscam2 isoform expression alternates between synaptic partners in the nerve cord. Our study demonstrates the importance of cell-specific alternative splicing in establishing the circuitry that underlies neuromotor patterning without inducing unwanted intercellular interactions.
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Affiliation(s)
- G. Lorenzo Odierna
- School of Biomedical Sciences, The University of Queensland, Brisbane, QLD, Australia
| | - Sarah K. Kerwin
- School of Biomedical Sciences, The University of Queensland, Brisbane, QLD, Australia
| | - Grace Ji-eun Shin
- School of Biomedical Sciences, The University of Queensland, Brisbane, QLD, Australia
- Department of Neurology, The Ohio State University Wexner Medical Center, Columbus, OH, United States
- The Neuroscience Research Institute, The Ohio State University, Columbus, OH, United States
- The Ohio State University Comprehensive Cancer Center, Columbus, OH, United States
| | - S. Sean Millard
- School of Biomedical Sciences, The University of Queensland, Brisbane, QLD, Australia
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3
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Leier HC, Foden AJ, Jindal DA, Wilkov AJ, Van der Linden Costello P, Vanderzalm PJ, Coutinho-Budd JC, Tabuchi M, Broihier HT. Glia control experience-dependent plasticity in an olfactory critical period. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.07.05.602232. [PMID: 39005309 PMCID: PMC11245089 DOI: 10.1101/2024.07.05.602232] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/16/2024]
Abstract
Sensory experience during developmental critical periods has lifelong consequences for circuit function and behavior, but the molecular and cellular mechanisms through which experience causes these changes are not well understood. The Drosophila antennal lobe houses synapses between olfactory sensory neurons (OSNs) and downstream projection neurons (PNs) in stereotyped glomeruli. Many glomeruli exhibit structural plasticity in response to early-life odor exposure, indicating a general sensitivity of the fly olfactory circuitry to early sensory experience. We recently found that glia regulate the development of the antennal lobe in young adult flies, leading us to ask if glia also drive experience-dependent plasticity. Here we define a critical period for structural and functional plasticity of OSN-PN synapses in the ethyl butyrate (EB)-sensitive glomerulus VM7. EB exposure for the first two days post-eclosion drives large-scale reductions in glomerular volume, presynapse number, and post-synaptic activity. The highly conserved engulfment receptor Draper is required for this critical period plasticity. Specifically, ensheathing glia upregulate Draper expression, invade the VM7 glomerulus, and phagocytose OSN presynaptic terminals in response to critical-period EB exposure. Crucially, synapse pruning during the critical period has long-term consequences for circuit function since both OSN-PN synapse number and spontaneous activity of PNs remain persistently decreased. These data demonstrate experience-dependent pruning of synapses in olfactory circuitry and argue that the Drosophila antennal lobe will be a powerful model for defining the function of glia in critical period plasticity.
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Affiliation(s)
- Hans C Leier
- Department of Neurosciences, Case Western Reserve University School of Medicine, Cleveland, United States
| | - Alexander J Foden
- Department of Neurosciences, Case Western Reserve University School of Medicine, Cleveland, United States
| | - Darren A Jindal
- Department of Neurosciences, Case Western Reserve University School of Medicine, Cleveland, United States
| | - Abigail J Wilkov
- Department of Neurosciences, Case Western Reserve University School of Medicine, Cleveland, United States
| | | | - Pamela J Vanderzalm
- Department of Biology, John Carroll University, University Heights, United States
| | - Jaeda C Coutinho-Budd
- Department of Neuroscience, University of Virginia School of Medicine, Charlottesville, United States
| | - Masashi Tabuchi
- Department of Neurosciences, Case Western Reserve University School of Medicine, Cleveland, United States
| | - Heather T Broihier
- Department of Neurosciences, Case Western Reserve University School of Medicine, Cleveland, United States
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4
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Menzies JAC, Maia Chagas A, Baden T, Alonso CR. A microRNA that controls the emergence of embryonic movement. eLife 2024; 13:RP95209. [PMID: 38869942 PMCID: PMC11175612 DOI: 10.7554/elife.95209] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2024] Open
Abstract
Movement is a key feature of animal systems, yet its embryonic origins are not fully understood. Here, we investigate the genetic basis underlying the embryonic onset of movement in Drosophila focusing on the role played by small non-coding RNAs (microRNAs, miRNAs). To this end, we first develop a quantitative behavioural pipeline capable of tracking embryonic movement in large populations of fly embryos, and using this system, discover that the Drosophila miRNA miR-2b-1 plays a role in the emergence of movement. Through the combination of spectral analysis of embryonic motor patterns, cell sorting and RNA in situs, genetic reconstitution tests, and neural optical imaging we define that miR-2b-1 influences the emergence of embryonic movement by exerting actions in the developing nervous system. Furthermore, through the combination of bioinformatics coupled to genetic manipulation of miRNA expression and phenocopy tests we identify a previously uncharacterised (but evolutionarily conserved) chloride channel encoding gene - which we term Movement Modulator (Motor) - as a genetic target that mechanistically links miR-2b-1 to the onset of movement. Cell-specific genetic reconstitution of miR-2b-1 expression in a null miRNA mutant background, followed by behavioural assays and target gene analyses, suggest that miR-2b-1 affects the emergence of movement through effects in sensory elements of the embryonic circuitry, rather than in the motor domain. Our work thus reports the first miRNA system capable of regulating embryonic movement, suggesting that other miRNAs are likely to play a role in this key developmental process in Drosophila as well as in other species.
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Affiliation(s)
- Jonathan AC Menzies
- Department of Neuroscience, Sussex Neuroscience, School of Life Sciences, University of SussexBrightonUnited Kingdom
| | - André Maia Chagas
- Department of Neuroscience, Sussex Neuroscience, School of Life Sciences, University of SussexBrightonUnited Kingdom
| | - Tom Baden
- Department of Neuroscience, Sussex Neuroscience, School of Life Sciences, University of SussexBrightonUnited Kingdom
| | - Claudio R Alonso
- Department of Neuroscience, Sussex Neuroscience, School of Life Sciences, University of SussexBrightonUnited Kingdom
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5
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Nelson N, Vita DJ, Broadie K. Experience-dependent glial pruning of synaptic glomeruli during the critical period. Sci Rep 2024; 14:9110. [PMID: 38643298 PMCID: PMC11032375 DOI: 10.1038/s41598-024-59942-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2024] [Accepted: 04/16/2024] [Indexed: 04/22/2024] Open
Abstract
Critical periods are temporally-restricted, early-life windows when sensory experience remodels synaptic connectivity to optimize environmental input. In the Drosophila juvenile brain, critical period experience drives synapse elimination, which is transiently reversible. Within olfactory sensory neuron (OSN) classes synapsing onto single projection neurons extending to brain learning/memory centers, we find glia mediate experience-dependent pruning of OSN synaptic glomeruli downstream of critical period odorant exposure. We find glial projections infiltrate brain neuropil in response to critical period experience, and use Draper (MEGF10) engulfment receptors to prune synaptic glomeruli. Downstream, we find antagonistic Basket (JNK) and Puckered (DUSP) signaling is required for the experience-dependent translocation of activated Basket into glial nuclei. Dependent on this signaling, we find critical period experience drives expression of the F-actin linking signaling scaffold Cheerio (FLNA), which is absolutely essential for the synaptic glomeruli pruning. We find Cheerio mediates experience-dependent regulation of the glial F-actin cytoskeleton for critical period remodeling. These results define a sequential pathway for experience-dependent brain synaptic glomeruli pruning in a strictly-defined critical period; input experience drives neuropil infiltration of glial projections, Draper/MEGF10 receptors activate a Basket/JNK signaling cascade for transcriptional activation, and Cheerio/FLNA induction regulates the glial actin cytoskeleton to mediate targeted synapse phagocytosis.
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Affiliation(s)
- Nichalas Nelson
- Department of Biological Sciences, Vanderbilt University and Medical Center, Nashville, TN, 37235, USA
| | - Dominic J Vita
- Department of Biological Sciences, Vanderbilt University and Medical Center, Nashville, TN, 37235, USA
| | - Kendal Broadie
- Department of Biological Sciences, Vanderbilt University and Medical Center, Nashville, TN, 37235, USA.
- Department of Cell and Developmental Biology, Vanderbilt University and Medical Center, Nashville, TN, 37235, USA.
- Kennedy Center for Research on Human Development, Vanderbilt University and Medical Center, Nashville, TN, 37235, USA.
- Vanderbilt Brain Institute, Vanderbilt University and Medical Center, Nashville, TN, 37235, USA.
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6
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Kann MR, Ackerman MK, Ackerman SD. OptoChamber: A Low-cost, Easy-to-Make, Customizable, and Multi-Chambered Electronic Device for Applying Optogenetic Stimulation to Larval Drosophila melanogaster. MICROPUBLICATION BIOLOGY 2024; 2024:10.17912/micropub.biology.001082. [PMID: 38681674 PMCID: PMC11056014 DOI: 10.17912/micropub.biology.001082] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Figures] [Subscribe] [Scholar Register] [Received: 12/06/2023] [Revised: 03/26/2024] [Accepted: 04/11/2024] [Indexed: 05/01/2024]
Abstract
Optogenetics is a powerful tool used to manipulate physiological processes in animals through cell-specific expression of genetically modified channelrhodopsins. In Drosophila melanogaster, optogenetics is frequently used for temporal control of neuronal activation or silencing through light-dependent actuation of cation and anion channelrhodopsins, respectively. The high setup costs and complexity associated with commercially available optogenetic systems prevents many investigators from exploring the use of this technology. We developed a low-cost, customizable, and easy-to-make optogenetics chamber (OptoChamber) and verified its functionality in a robust cellular assay: activity-dependent remodeling of larval motor neurons in Drosophila embryos.
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Affiliation(s)
- Michael Ryan Kann
- Department of Pathology and Immunology, Brian Immunology & Glia (BIG) Center, Washington University in St. Louis School of Medicine, St Louis, Missouri, United States
- University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States
| | | | - Sarah D. Ackerman
- Department of Pathology and Immunology, Brian Immunology & Glia (BIG) Center, Washington University in St. Louis School of Medicine, St Louis, Missouri, United States
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7
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Chalmers N, Masouti E, Beckervordersandforth R. Astrocytes in the adult dentate gyrus-balance between adult and developmental tasks. Mol Psychiatry 2024; 29:982-991. [PMID: 38177351 PMCID: PMC11176073 DOI: 10.1038/s41380-023-02386-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/04/2023] [Revised: 12/12/2023] [Accepted: 12/14/2023] [Indexed: 01/06/2024]
Abstract
Astrocytes, a major glial cell type in the brain, are indispensable for the integration, maintenance and survival of neurons during development and adulthood. Both life phases make specific demands on the molecular and physiological properties of astrocytes, and most research projects traditionally focus on either developmental or adult astrocyte functions. In most brain regions, the generation of brain cells and the establishment of neural circuits ends with postnatal development. However, few neurogenic niches exist in the adult brain in which new neurons and glial cells are produced lifelong, and the integration of new cells into functional circuits represent a very special form of plasticity. Consequently, in the neurogenic niche, the astrocytes must be equipped to execute both mature and developmental tasks in order to integrate newborn neurons into the circuit and yet maintain overall homeostasis without affecting the preexisting neurons. In this review, we focus on astrocytes of the hippocampal dentate gyrus (DG), and discuss specific features of the astrocytic compartment that may allow the execution of both tasks. Firstly, astrocytes of the adult DG are molecularly, morphologically and functionally diverse, and the distinct astrocytes subtypes are characterized by their localization to DG layers. This spatial separation may lead to a functional specification of astrocytes subtypes according to the neuronal structures they are embedded in, hence a division of labor. Secondly, the astrocytic compartment is not static, but steadily increasing in numbers due to lifelong astrogenesis. Interestingly, astrogenesis can adapt to environmental and behavioral stimuli, revealing an unexpected astrocyte dynamic that allows the niche to adopt to changing demands. The diversity and dynamic of astrocytes in the adult DG implicate a vital contribution to hippocampal plasticity and represent an interesting model to uncover mechanisms how astrocytes simultaneously fulfill developmental and adult tasks.
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Affiliation(s)
- Nicholas Chalmers
- Institute of Biochemistry, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Evangelia Masouti
- Institute of Biochemistry, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
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8
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Shinozaki Y, Namekata K, Guo X, Harada T. Glial cells as a promising therapeutic target of glaucoma: beyond the IOP. FRONTIERS IN OPHTHALMOLOGY 2024; 3:1310226. [PMID: 38983026 PMCID: PMC11182302 DOI: 10.3389/fopht.2023.1310226] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/09/2023] [Accepted: 12/18/2023] [Indexed: 07/11/2024]
Abstract
Glial cells, a type of non-neuronal cell found in the central nervous system (CNS), play a critical role in maintaining homeostasis and regulating CNS functions. Recent advancements in technology have paved the way for new therapeutic strategies in the fight against glaucoma. While intraocular pressure (IOP) is the most well-known modifiable risk factor, a significant number of glaucoma patients have normal IOP levels. Because glaucoma is a complex, multifactorial disease influenced by various factors that contribute to its onset and progression, it is imperative that we consider factors beyond IOP to effectively prevent or slow down the disease's advancement. In the realm of CNS neurodegenerative diseases, glial cells have emerged as key players due to their pivotal roles in initiating and hastening disease progression. The inhibition of dysregulated glial function holds the potential to protect neurons and restore brain function. Consequently, glial cells represent an enticing therapeutic candidate for glaucoma, even though the majority of glaucoma research has historically concentrated solely on retinal ganglion cells (RGCs). In addition to the neuroprotection of RGCs, the proper regulation of glial cell function can also facilitate structural and functional recovery in the retina. In this review, we offer an overview of recent advancements in understanding the non-cell-autonomous mechanisms underlying the pathogenesis of glaucoma. Furthermore, state-of-the-art technologies have opened up possibilities for regenerating the optic nerve, which was previously believed to be incapable of regeneration. We will also delve into the potential roles of glial cells in the regeneration of the optic nerve and the restoration of visual function.
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Affiliation(s)
- Youichi Shinozaki
- Visual Research Project, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| | - Kazuhiko Namekata
- Visual Research Project, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| | - Xiaoli Guo
- Visual Research Project, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| | - Takayuki Harada
- Visual Research Project, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
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9
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Chen J, Stork T, Kang Y, Nardone KAM, Auer F, Farrell RJ, Jay TR, Heo D, Sheehan A, Paton C, Nagel KI, Schoppik D, Monk KR, Freeman MR. Astrocyte growth is driven by the Tre1/S1pr1 phospholipid-binding G protein-coupled receptor. Neuron 2024; 112:93-112.e10. [PMID: 38096817 PMCID: PMC11073822 DOI: 10.1016/j.neuron.2023.11.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Revised: 07/31/2023] [Accepted: 11/08/2023] [Indexed: 01/06/2024]
Abstract
Astrocytes play crucial roles in regulating neural circuit function by forming a dense network of synapse-associated membrane specializations, but signaling pathways regulating astrocyte morphogenesis remain poorly defined. Here, we show the Drosophila lipid-binding G protein-coupled receptor (GPCR) Tre1 is required for astrocytes to establish their intricate morphology in vivo. The lipid phosphate phosphatases Wunen/Wunen2 also regulate astrocyte morphology and, via Tre1, mediate astrocyte-astrocyte competition for growth-promoting lipids. Loss of s1pr1, the functional analog of Tre1 in zebrafish, disrupts astrocyte process elaboration, and live imaging and pharmacology demonstrate that S1pr1 balances proper astrocyte process extension/retraction dynamics during growth. Loss of Tre1 in flies or S1pr1 in zebrafish results in defects in simple assays of motor behavior. Tre1 and S1pr1 are thus potent evolutionarily conserved regulators of the elaboration of astrocyte morphological complexity and, ultimately, astrocyte control of behavior.
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Affiliation(s)
- Jiakun Chen
- Vollum Institute, Oregon Health & Science University, Portland, OR 97239, USA.
| | - Tobias Stork
- Vollum Institute, Oregon Health & Science University, Portland, OR 97239, USA
| | - Yunsik Kang
- Vollum Institute, Oregon Health & Science University, Portland, OR 97239, USA
| | - Katherine A M Nardone
- Departments of Otolaryngology and Neuroscience and Physiology, Neuroscience Institute, New York University Grossman School of Medicine, New York, NY 10016, USA
| | - Franziska Auer
- Departments of Otolaryngology and Neuroscience and Physiology, Neuroscience Institute, New York University Grossman School of Medicine, New York, NY 10016, USA
| | - Ryan J Farrell
- Neuroscience Institute, NYU Medical Center, New York, NY 10016, USA
| | - Taylor R Jay
- Vollum Institute, Oregon Health & Science University, Portland, OR 97239, USA
| | - Dongeun Heo
- Vollum Institute, Oregon Health & Science University, Portland, OR 97239, USA
| | - Amy Sheehan
- Vollum Institute, Oregon Health & Science University, Portland, OR 97239, USA
| | - Cameron Paton
- Vollum Institute, Oregon Health & Science University, Portland, OR 97239, USA
| | | | - David Schoppik
- Departments of Otolaryngology and Neuroscience and Physiology, Neuroscience Institute, New York University Grossman School of Medicine, New York, NY 10016, USA
| | - Kelly R Monk
- Vollum Institute, Oregon Health & Science University, Portland, OR 97239, USA.
| | - Marc R Freeman
- Vollum Institute, Oregon Health & Science University, Portland, OR 97239, USA.
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10
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Starkey J, Horstick EJ, Ackerman SD. Glial regulation of critical period plasticity. Front Cell Neurosci 2023; 17:1247335. [PMID: 38034592 PMCID: PMC10687281 DOI: 10.3389/fncel.2023.1247335] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2023] [Accepted: 10/30/2023] [Indexed: 12/02/2023] Open
Abstract
Animal behavior, from simple to complex, is dependent on the faithful wiring of neurons into functional neural circuits. Neural circuits undergo dramatic experience-dependent remodeling during brief developmental windows called critical periods. Environmental experience during critical periods of plasticity produces sustained changes to circuit function and behavior. Precocious critical period closure is linked to autism spectrum disorders, whereas extended synaptic remodeling is thought to underlie circuit dysfunction in schizophrenia. Thus, resolving the mechanisms that instruct critical period timing is important to our understanding of neurodevelopmental disorders. Control of critical period timing is modulated by neuron-intrinsic cues, yet recent data suggest that some determinants are derived from neighboring glial cells (astrocytes, microglia, and oligodendrocytes). As glia make up 50% of the human brain, understanding how these diverse cells communicate with neurons and with each other to sculpt neural plasticity, especially during specialized critical periods, is essential to our fundamental understanding of circuit development and maintenance.
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Affiliation(s)
- Jacob Starkey
- Department of Biology, West Virginia University, Morgantown, WV, United States
| | - Eric J. Horstick
- Department of Biology, West Virginia University, Morgantown, WV, United States
- Department of Neuroscience, West Virginia University, Morgantown, WV, United States
| | - Sarah D. Ackerman
- Department of Pathology and Immunology, Brain Immunology and Glia Center, Washington University School of Medicine, St. Louis, MO, United States
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11
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Barnett D, Bohmbach K, Grelot V, Charlet A, Dallérac G, Ju YH, Nagai J, Orr AG. Astrocytes as Drivers and Disruptors of Behavior: New Advances in Basic Mechanisms and Therapeutic Targeting. J Neurosci 2023; 43:7463-7471. [PMID: 37940585 PMCID: PMC10634555 DOI: 10.1523/jneurosci.1376-23.2023] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Revised: 08/13/2023] [Accepted: 08/22/2023] [Indexed: 11/10/2023] Open
Abstract
Astrocytes are emerging as key regulators of cognitive function and behavior. This review highlights some of the latest advances in the understanding of astrocyte roles in different behavioral domains across lifespan and in disease. We address specific molecular and circuit mechanisms by which astrocytes modulate behavior, discuss their functional diversity and versatility, and highlight emerging astrocyte-targeted treatment strategies that might alleviate behavioral and cognitive dysfunction in pathologic conditions. Converging evidence across different model systems and manipulations is revealing that astrocytes regulate behavioral processes in a precise and context-dependent manner. Improved understanding of these astrocytic functions may generate new therapeutic strategies for various conditions with cognitive and behavioral impairments.
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Affiliation(s)
- Daniel Barnett
- Appel Alzheimer's Disease Research Institute, Weill Cornell Medicine, New York, New York 10021
- Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, New York, New York 10021
- Neuroscience Graduate Program, Weill Cornell Medicine, New York, New York 10021
| | - Kirsten Bohmbach
- Institute of Cellular Neurosciences, Medical Faculty, University of Bonn, 53127 Bonn, Germany
| | - Valentin Grelot
- Institute of Cellular and Integrative Neuroscience, Centre National de la Recherche Scientifique and University of Strasbourg, Strasbourg, 67000, France
| | - Alexandre Charlet
- Institute of Cellular and Integrative Neuroscience, Centre National de la Recherche Scientifique and University of Strasbourg, Strasbourg, 67000, France
| | - Glenn Dallérac
- Centre National de la Recherche Scientifique and Paris-Saclay University, Paris-Saclay Institute for Neurosciences, Paris, 91400, France
| | - Yeon Ha Ju
- Department of Psychiatry and Neuroscience, University of Texas-Austin Dell Medical School, Austin, Texas 78712
| | - Jun Nagai
- RIKEN Center for Brain Science, Laboratory for Glia-Neuron Circuit Dynamics, Saitama, 351-0198, Japan
| | - Anna G Orr
- Appel Alzheimer's Disease Research Institute, Weill Cornell Medicine, New York, New York 10021
- Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, New York, New York 10021
- Neuroscience Graduate Program, Weill Cornell Medicine, New York, New York 10021
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12
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Martínez-Gallego I, Rodríguez-Moreno A. Adenosine and Astrocytes Control Critical Periods of Neural Plasticity. Neuroscientist 2023; 29:532-537. [PMID: 36245418 DOI: 10.1177/10738584221126632] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/25/2023]
Abstract
Windows of plasticity are fundamental for the correct formation of definitive brain circuits; these periods drive sensory and motor learning during development and ultimately learning and memory in adults. However, establishing windows of plasticity also imposes limitations on the central nervous system in terms of its capacity to recover from injury. Recent evidence highlights the important role that astrocytes and adenosine seem to play in controlling the duration of these critical periods of plasticity.
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13
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Brandt JP, Smith CJ. Piezo1-mediated spontaneous calcium transients in satellite glia impact dorsal root ganglia development. PLoS Biol 2023; 21:e3002319. [PMID: 37747915 PMCID: PMC10564127 DOI: 10.1371/journal.pbio.3002319] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Revised: 10/10/2023] [Accepted: 08/31/2023] [Indexed: 09/27/2023] Open
Abstract
Spontaneous Ca2+ transients of neural cells is a hallmark of the developing nervous system. It is widely accepted that chemical signals, like neurotransmitters, contribute to spontaneous Ca2+ transients in the nervous system. Here, we reveal an additional mechanism of spontaneous Ca2+ transients that is mechanosensitive in the peripheral nervous system (PNS) using intravital imaging of growing dorsal root ganglia (DRG) in zebrafish embryos. GCaMP6s imaging shows that developing DRG satellite glia contain distinct spontaneous Ca2+ transients, classified into simultaneous, isolated, and microdomains. Longitudinal analysis over days in development demonstrates that as DRG satellite glia become more synchronized, isolated Ca2+ transients remain constant. Using a chemical screen, we identify that Ca2+ transients in DRG glia are dependent on mechanical properties, which we confirmed using an experimental application of mechanical force. We find that isolated spontaneous Ca2+ transients of the glia during development is altered by manipulation of mechanosensitive protein Piezo1, which is expressed in the developing ganglia. In contrast, simultaneous Ca2+ transients of DRG satellite glia is not Piezo1-mediated, thus demonstrating that distinct mechanisms mediate subtypes of spontaneous Ca2+ transients. Activating Piezo1 eventually impacts the cell abundance of DRG cells and behaviors that are driven by DRG neurons. Together, our results reveal mechanistically distinct subtypes of Ca2+ transients in satellite glia and introduce mechanobiology as a critical component of spontaneous Ca2+ transients in the developing PNS.
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Affiliation(s)
- Jacob P. Brandt
- Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana, United States of America
- The Center for Stem Cells and Regenerative Medicine, University of Notre Dame, Notre Dame, Indiana, United States of America
| | - Cody J. Smith
- Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana, United States of America
- The Center for Stem Cells and Regenerative Medicine, University of Notre Dame, Notre Dame, Indiana, United States of America
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14
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Wang Y, Zhang R, Huang S, Valverde PTT, Lobb-Rabe M, Ashley J, Venkatasubramanian L, Carrillo RA. Glial Draper signaling triggers cross-neuron plasticity in bystander neurons after neuronal cell death in Drosophila. Nat Commun 2023; 14:4452. [PMID: 37488133 PMCID: PMC10366216 DOI: 10.1038/s41467-023-40142-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Accepted: 07/07/2023] [Indexed: 07/26/2023] Open
Abstract
Neuronal cell death and subsequent brain dysfunction are hallmarks of aging and neurodegeneration, but how the nearby healthy neurons (bystanders) respond to the death of their neighbors is not fully understood. In the Drosophila larval neuromuscular system, bystander motor neurons can structurally and functionally compensate for the loss of their neighbors by increasing their terminal bouton number and activity. We term this compensation as cross-neuron plasticity, and in this study, we demonstrate that the Drosophila engulfment receptor, Draper, and the associated kinase, Shark, are required for cross-neuron plasticity. Overexpression of the Draper-I isoform boosts cross-neuron plasticity, implying that the strength of plasticity correlates with Draper signaling. In addition, we find that functional cross-neuron plasticity can be induced at different developmental stages. Our work uncovers a role for Draper signaling in cross-neuron plasticity and provides insights into how healthy bystander neurons respond to the loss of their neighboring neurons.
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Affiliation(s)
- Yupu Wang
- Department of Molecular Genetics and Cellular Biology, University of Chicago, Chicago, IL, 60637, USA.
- Neuroscience Institute, University of Chicago, Chicago, IL, 60637, USA.
- Howard Hughes Medical Institute, Janelia Research Campus, Ashburn, VA, 20147, USA.
| | - Ruiling Zhang
- Department of Molecular Genetics and Cellular Biology, University of Chicago, Chicago, IL, 60637, USA
- Neuroscience Institute, University of Chicago, Chicago, IL, 60637, USA
- Committee on Development, Regeneration, and Stem Cell Biology, University of Chicago, Chicago, IL, 60637, USA
| | - Sihao Huang
- Program in Biochemistry and Molecular Biophysics, University of Chicago, Chicago, IL, 60637, USA
| | - Parisa Tajalli Tehrani Valverde
- Department of Molecular Genetics and Cellular Biology, University of Chicago, Chicago, IL, 60637, USA
- Neuroscience Institute, University of Chicago, Chicago, IL, 60637, USA
- Committee on Development, Regeneration, and Stem Cell Biology, University of Chicago, Chicago, IL, 60637, USA
| | - Meike Lobb-Rabe
- Department of Molecular Genetics and Cellular Biology, University of Chicago, Chicago, IL, 60637, USA
- Neuroscience Institute, University of Chicago, Chicago, IL, 60637, USA
- Program in Cell and Molecular Biology, University of Chicago, Chicago, IL, 60637, USA
| | - James Ashley
- Department of Molecular Genetics and Cellular Biology, University of Chicago, Chicago, IL, 60637, USA
- Neuroscience Institute, University of Chicago, Chicago, IL, 60637, USA
| | | | - Robert A Carrillo
- Department of Molecular Genetics and Cellular Biology, University of Chicago, Chicago, IL, 60637, USA.
- Neuroscience Institute, University of Chicago, Chicago, IL, 60637, USA.
- Committee on Development, Regeneration, and Stem Cell Biology, University of Chicago, Chicago, IL, 60637, USA.
- Program in Cell and Molecular Biology, University of Chicago, Chicago, IL, 60637, USA.
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15
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Pereira MJ, Ayana R, Holt MG, Arckens L. Chemogenetic manipulation of astrocyte activity at the synapse- a gateway to manage brain disease. Front Cell Dev Biol 2023; 11:1193130. [PMID: 37534103 PMCID: PMC10393042 DOI: 10.3389/fcell.2023.1193130] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Accepted: 06/14/2023] [Indexed: 08/04/2023] Open
Abstract
Astrocytes are the major glial cell type in the central nervous system (CNS). Initially regarded as supportive cells, it is now recognized that this highly heterogeneous cell population is an indispensable modulator of brain development and function. Astrocytes secrete neuroactive molecules that regulate synapse formation and maturation. They also express hundreds of G protein-coupled receptors (GPCRs) that, once activated by neurotransmitters, trigger intracellular signalling pathways that can trigger the release of gliotransmitters which, in turn, modulate synaptic transmission and neuroplasticity. Considering this, it is not surprising that astrocytic dysfunction, leading to synaptic impairment, is consistently described as a factor in brain diseases, whether they emerge early or late in life due to genetic or environmental factors. Here, we provide an overview of the literature showing that activation of genetically engineered GPCRs, known as Designer Receptors Exclusively Activated by Designer Drugs (DREADDs), to specifically modulate astrocyte activity partially mimics endogenous signalling pathways in astrocytes and improves neuronal function and behavior in normal animals and disease models. Therefore, we propose that expressing these genetically engineered GPCRs in astrocytes could be a promising strategy to explore (new) signalling pathways which can be used to manage brain disorders. The precise molecular, functional and behavioral effects of this type of manipulation, however, differ depending on the DREADD receptor used, targeted brain region and timing of the intervention, between healthy and disease conditions. This is likely a reflection of regional and disease/disease progression-associated astrocyte heterogeneity. Therefore, a thorough investigation of the effects of such astrocyte manipulation(s) must be conducted considering the specific cellular and molecular environment characteristic of each disease and disease stage before this has therapeutic applicability.
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Affiliation(s)
- Maria João Pereira
- Department of Biology, Laboratory of Neuroplasticity and Neuroproteomics, KU Leuven, Leuven, Belgium
- KU Leuven Brain Institute, Leuven, Belgium
| | - Rajagopal Ayana
- Department of Biology, Laboratory of Neuroplasticity and Neuroproteomics, KU Leuven, Leuven, Belgium
- KU Leuven Brain Institute, Leuven, Belgium
| | - Matthew G. Holt
- Instituto de Investigação e Inovação em Saúde (i3S), Laboratory of Synapse Biology, Universidade do Porto, Porto, Portugal
| | - Lutgarde Arckens
- Department of Biology, Laboratory of Neuroplasticity and Neuroproteomics, KU Leuven, Leuven, Belgium
- KU Leuven Brain Institute, Leuven, Belgium
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16
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Watanabe A, Guo C, Sjöström PJ. The developmental profile of visual cortex astrocytes. iScience 2023; 26:106828. [PMID: 37250801 PMCID: PMC10212985 DOI: 10.1016/j.isci.2023.106828] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 03/08/2023] [Accepted: 05/03/2023] [Indexed: 05/31/2023] Open
Abstract
We investigated how astrocytes in layer 5 mouse visual cortex mature over postnatal days (P) 3-50. Across this age range, resting membrane potential increased, input resistance decreased, and membrane responses became more passive with age. Two-photon (2p) and confocal imaging of dye-loaded cells revealed that gap-junction coupling increased starting ∼P7. Morphological reconstructions revealed increased branch density but shorter branches after P20, suggesting that astrocyte branches may get pruned as tiling is established. Finally, we visualized spontaneous Ca2+ transients with 2p microscopy and found that Ca2+ events decorrelated, became more frequent and briefer with age. As astrocytes mature, spontaneous Ca2+ activity thus changes from relatively cell-wide, synchronous waves to local transients. Several astrocyte properties were stably mature from ∼P15, coinciding with eye opening, although morphology continued to develop. Our findings provide a descriptive foundation of astrocyte maturation, useful for the study of astrocytic impact on visual cortex critical period plasticity.
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Affiliation(s)
- Airi Watanabe
- Centre for Research in Neuroscience, Brain Repair and Integrative Neuroscience Program, Department of Medicine, The Research Institute of the McGill University Health Centre, Montreal General Hospital, Montreal, QC H3G 1A4, Canada
- Integrated Program in Neuroscience, Irving Ludmer Building, McGill University, 1033 Pine Avenue West, Montreal, QC H3A 1A1, Canada
| | - Connie Guo
- Centre for Research in Neuroscience, Brain Repair and Integrative Neuroscience Program, Department of Medicine, The Research Institute of the McGill University Health Centre, Montreal General Hospital, Montreal, QC H3G 1A4, Canada
- Department of Anatomy and Cell Biology, Faculty of Science, McGill University, Strathcona Anatomy and Dentistry Building, 3640 University Street, Montreal, QC H3A 0C7, Canada
| | - Per Jesper Sjöström
- Centre for Research in Neuroscience, Brain Repair and Integrative Neuroscience Program, Department of Medicine, The Research Institute of the McGill University Health Centre, Montreal General Hospital, Montreal, QC H3G 1A4, Canada
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17
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Jindal DA, Leier HC, Salazar G, Foden AJ, Seitz EA, Wilkov AJ, Coutinho-Budd JC, Broihier HT. Early Draper-mediated glial refinement of neuropil architecture and synapse number in the Drosophila antennal lobe. Front Cell Neurosci 2023; 17:1166199. [PMID: 37333889 PMCID: PMC10272751 DOI: 10.3389/fncel.2023.1166199] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Accepted: 05/15/2023] [Indexed: 06/20/2023] Open
Abstract
Glial phagocytic activity refines connectivity, though molecular mechanisms regulating this exquisitely sensitive process are incompletely defined. We developed the Drosophila antennal lobe as a model for identifying molecular mechanisms underlying glial refinement of neural circuits in the absence of injury. Antennal lobe organization is stereotyped and characterized by individual glomeruli comprised of unique olfactory receptor neuronal (ORN) populations. The antennal lobe interacts extensively with two glial subtypes: ensheathing glia wrap individual glomeruli, while astrocytes ramify considerably within them. Phagocytic roles for glia in the uninjured antennal lobe are largely unknown. Thus, we tested whether Draper regulates ORN terminal arbor size, shape, or presynaptic content in two representative glomeruli: VC1 and VM7. We find that glial Draper limits the size of individual glomeruli and restrains their presynaptic content. Moreover, glial refinement is apparent in young adults, a period of rapid terminal arbor and synapse growth, indicating that synapse addition and elimination occur simultaneously. Draper has been shown to be expressed in ensheathing glia; unexpectedly, we find it expressed at high levels in late pupal antennal lobe astrocytes. Surprisingly, Draper plays differential roles in ensheathing glia and astrocytes in VC1 and VM7. In VC1, ensheathing glial Draper plays a more significant role in shaping glomerular size and presynaptic content; while in VM7, astrocytic Draper plays the larger role. Together, these data indicate that astrocytes and ensheathing glia employ Draper to refine circuitry in the antennal lobe before the terminal arbors reach their mature form and argue for local heterogeneity of neuron-glia interactions.
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Affiliation(s)
- Darren A. Jindal
- Department of Neurosciences, Case Western Reserve University School of Medicine, Cleveland, OH, United States
| | - Hans C. Leier
- Department of Neurosciences, Case Western Reserve University School of Medicine, Cleveland, OH, United States
| | - Gabriela Salazar
- Department of Neuroscience, University of Virginia School of Medicine, Charlottesville, VA, United States
| | - Alexander J. Foden
- Department of Neurosciences, Case Western Reserve University School of Medicine, Cleveland, OH, United States
| | - Elizabeth A. Seitz
- Department of Neurosciences, Case Western Reserve University School of Medicine, Cleveland, OH, United States
| | - Abigail J. Wilkov
- Department of Neurosciences, Case Western Reserve University School of Medicine, Cleveland, OH, United States
| | - Jaeda C. Coutinho-Budd
- Department of Neuroscience, University of Virginia School of Medicine, Charlottesville, VA, United States
| | - Heather T. Broihier
- Department of Neurosciences, Case Western Reserve University School of Medicine, Cleveland, OH, United States
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18
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Purushotham SS, Buskila Y. Astrocytic modulation of neuronal signalling. FRONTIERS IN NETWORK PHYSIOLOGY 2023; 3:1205544. [PMID: 37332623 PMCID: PMC10269688 DOI: 10.3389/fnetp.2023.1205544] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Accepted: 05/18/2023] [Indexed: 06/20/2023]
Abstract
Neuronal signalling is a key element in neuronal communication and is essential for the proper functioning of the CNS. Astrocytes, the most prominent glia in the brain play a key role in modulating neuronal signalling at the molecular, synaptic, cellular, and network levels. Over the past few decades, our knowledge about astrocytes and their functioning has evolved from considering them as merely a brain glue that provides structural support to neurons, to key communication elements. Astrocytes can regulate the activity of neurons by controlling the concentrations of ions and neurotransmitters in the extracellular milieu, as well as releasing chemicals and gliotransmitters that modulate neuronal activity. The aim of this review is to summarise the main processes through which astrocytes are modulating brain function. We will systematically distinguish between direct and indirect pathways in which astrocytes affect neuronal signalling at all levels. Lastly, we will summarize pathological conditions that arise once these signalling pathways are impaired focusing on neurodegeneration.
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Affiliation(s)
| | - Yossi Buskila
- School of Medicine, Western Sydney University, Campbelltown, NSW, Australia
- The MARCS Institute, Western Sydney University, Campbelltown, NSW, Australia
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19
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Gau YTA, Hsu E, Cha J, Pak RW, Looger LL, Kang JU, Bergles DE. Multicore fiber optic imaging reveals that astrocyte calcium activity in the cerebral cortex is modulated by internal motivational state. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.18.541390. [PMID: 37292710 PMCID: PMC10245653 DOI: 10.1101/2023.05.18.541390] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Astrocytes are a direct target of neuromodulators and can influence neuronal activity on broad spatial and temporal scales through their close proximity to synapses. However, our knowledge about how astrocytes are functionally recruited during different animal behaviors and their diverse effects on the CNS remains limited. To enable measurement of astrocyte activity patterns in vivo during normative behaviors, we developed a high-resolution, long working distance, multi-core fiber optic imaging platform that allows visualization of cortical astrocyte calcium transients through a cranial window in freely moving mice. Using this platform, we defined the spatiotemporal dynamics of astrocytes during diverse behaviors, ranging from circadian fluctuations to novelty exploration, showing that astrocyte activity patterns are more variable and less synchronous than apparent in head-immobilized imaging conditions. Although the activity of astrocytes in visual cortex was highly synchronized during quiescence to arousal transitions, individual astrocytes often exhibited distinct thresholds and activity patterns during explorative behaviors, in accordance with their molecular diversity, allowing temporal sequencing across the astrocyte network. Imaging astrocyte activity during self-initiated behaviors revealed that noradrenergic and cholinergic systems act synergistically to recruit astrocytes during state transitions associated with arousal and attention, which was profoundly modulated by internal state. The distinct activity patterns exhibited by astrocytes in the cerebral cortex may provide a means to vary their neuromodulatory influence in response to different behaviors and internal states.
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Affiliation(s)
- Yung-Tian A. Gau
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University, Baltimore, MD 21205, United States
| | - Eric Hsu
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University, Baltimore, MD 21205, United States
| | - Jaepyeong Cha
- Department of Electrical and Computer Engineering, Johns Hopkins University, Baltimore, MD 21218, United States
| | - Rebecca W. Pak
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD 21205, United States
| | - Loren L. Looger
- Howard Hughes Medical Institute, Department of Neurosciences, University of California San Diego, La Jolla, CA 92093, United States
| | - Jin U. Kang
- Department of Electrical and Computer Engineering, Johns Hopkins University, Baltimore, MD 21218, United States
- Kavli Neuroscience Discovery Institute, Johns Hopkins University, Baltimore, MD 21205, United States
| | - Dwight E. Bergles
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University, Baltimore, MD 21205, United States
- Kavli Neuroscience Discovery Institute, Johns Hopkins University, Baltimore, MD 21205, United States
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20
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Andrade-Talavera Y, Pérez-Rodríguez M, Prius-Mengual J, Rodríguez-Moreno A. Neuronal and astrocyte determinants of critical periods of plasticity. Trends Neurosci 2023:S0166-2236(23)00105-4. [PMID: 37202300 DOI: 10.1016/j.tins.2023.04.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Revised: 03/20/2023] [Accepted: 04/24/2023] [Indexed: 05/20/2023]
Abstract
Windows of plasticity allow environmental experiences to produce intense activity-dependent changes during postnatal development. The reordering and refinement of neural connections occurs during these periods, significantly influencing the formation of brain circuits and physiological processes in adults. Recent advances have shed light on factors that determine the onset and duration of sensitive and critical periods of plasticity. Although GABAergic inhibition has classically been implicated in closing windows of plasticity, astrocytes and adenosinergic inhibition have also emerged more recently as key determinants of the duration of these periods of plasticity. Here, we review novel aspects of the involvement of GABAergic inhibition, the possible role of presynaptic NMDARs, and the emerging roles of astrocytes and adenosinergic inhibition in determining the duration of windows of plasticity in different brain regions.
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Affiliation(s)
- Yuniesky Andrade-Talavera
- Laboratory of Cellular Neuroscience and Plasticity, Department of Physiology, Anatomy and Cell Biology, Universidad Pablo de Olavide, ES-41013 Seville, Spain
| | - Mikel Pérez-Rodríguez
- Laboratory of Cellular Neuroscience and Plasticity, Department of Physiology, Anatomy and Cell Biology, Universidad Pablo de Olavide, ES-41013 Seville, Spain
| | - José Prius-Mengual
- Laboratory of Cellular Neuroscience and Plasticity, Department of Physiology, Anatomy and Cell Biology, Universidad Pablo de Olavide, ES-41013 Seville, Spain
| | - Antonio Rodríguez-Moreno
- Laboratory of Cellular Neuroscience and Plasticity, Department of Physiology, Anatomy and Cell Biology, Universidad Pablo de Olavide, ES-41013 Seville, Spain.
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21
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Hageter J, Starkey J, Horstick EJ. Thalamic regulation of a visual critical period and motor behavior. Cell Rep 2023; 42:112287. [PMID: 36952349 PMCID: PMC10514242 DOI: 10.1016/j.celrep.2023.112287] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Revised: 02/02/2023] [Accepted: 03/03/2023] [Indexed: 03/24/2023] Open
Abstract
During the visual critical period (CP), sensory experience refines the structure and function of visual circuits. The basis of this plasticity was long thought to be limited to cortical circuits, but recently described thalamic plasticity challenges this dogma and demonstrates greater complexity underlying visual plasticity. Yet how visual experience modulates thalamic neurons or how the thalamus modulates CP timing is incompletely understood. Using a larval zebrafish, thalamus-centric ocular dominance model, we show functional changes in the thalamus and a role of inhibitory signaling to establish CP timing using a combination of functional imaging, optogenetics, and pharmacology. Hemisphere-specific changes in genetically defined thalamic neurons correlate with changes in visuomotor behavior, establishing a role of thalamic plasticity in modulating motor performance. Our work demonstrates that visual plasticity is broadly conserved and that visual experience leads to neuron-level functional changes in the thalamus that require inhibitory signaling to establish critical period timing.
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Affiliation(s)
- John Hageter
- Department of Biology, West Virginia University, Morgantown, WV 26506, USA
| | - Jacob Starkey
- Department of Biology, West Virginia University, Morgantown, WV 26506, USA
| | - Eric J Horstick
- Department of Biology, West Virginia University, Morgantown, WV 26506, USA; Department of Neuroscience, West Virginia University, Morgantown, WV 26506, USA.
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22
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Delepine C, Shih J, Li K, Gaudeaux P, Sur M. Differential Effects of Astrocyte Manipulations on Learned Motor Behavior and Neuronal Ensembles in the Motor Cortex. J Neurosci 2023; 43:2696-2713. [PMID: 36894315 PMCID: PMC10089242 DOI: 10.1523/jneurosci.1982-22.2023] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Revised: 01/31/2023] [Accepted: 03/01/2023] [Indexed: 03/11/2023] Open
Abstract
Although motor cortex is crucial for learning precise and reliable movements, whether and how astrocytes contribute to its plasticity and function during motor learning is unknown. Here, we report that astrocyte-specific manipulations in primary motor cortex (M1) during a lever push task alter motor learning and execution, as well as the underlying neuronal population coding. Mice that express decreased levels of the astrocyte glutamate transporter 1 (GLT1) show impaired and variable movement trajectories, whereas mice with increased astrocyte Gq signaling show decreased performance rates, delayed response times, and impaired trajectories. In both groups, which include male and female mice, M1 neurons have altered interneuronal correlations and impaired population representations of task parameters, including response time and movement trajectories. RNA sequencing further supports a role for M1 astrocytes in motor learning and shows changes in astrocytic expression of glutamate transporter genes, GABA transporter genes, and extracellular matrix protein genes in mice that have acquired this learned behavior. Thus, astrocytes coordinate M1 neuronal activity during motor learning, and our results suggest that this contributes to learned movement execution and dexterity through mechanisms that include regulation of neurotransmitter transport and calcium signaling.SIGNIFICANCE STATEMENT We demonstrate for the first time that in the M1 of mice, astrocyte function is critical for coordinating neuronal population activity during motor learning. We demonstrate that knockdown of astrocyte glutamate transporter GLT1 affects specific components of learning, such as smooth trajectory formation. Altering astrocyte calcium signaling by activation of Gq-DREADD upregulates GLT1 and affects other components of learning, such as response rates and reaction times as well as trajectory smoothness. In both manipulations, neuronal activity in motor cortex is dysregulated, but in different ways. Thus, astrocytes have a crucial role in motor learning via their influence on motor cortex neurons, and they do so by mechanisms that include regulation of glutamate transport and calcium signals.
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Affiliation(s)
- Chloe Delepine
- The Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
- Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
| | - Jennifer Shih
- The Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
- Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
| | - Keji Li
- The Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
- Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
| | - Pierre Gaudeaux
- The Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
| | - Mriganka Sur
- The Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
- Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
- Simons Center for the Social Brain, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
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23
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Wang Y, Zhang R, Huang S, Valverde PTT, Lobb-Rabe M, Ashley J, Venkatasubramanian L, Carrillo RA. Glial Draper signaling triggers cross-neuron plasticity in bystander neurons after neuronal cell death. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.09.536190. [PMID: 37090512 PMCID: PMC10120647 DOI: 10.1101/2023.04.09.536190] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/25/2023]
Abstract
Neuronal cell death and subsequent brain dysfunction are hallmarks of aging and neurodegeneration, but how the nearby healthy neurons (bystanders) respond to the cell death of their neighbors is not fully understood. In the Drosophila larval neuromuscular system, bystander motor neurons can structurally and functionally compensate for the loss of their neighbors by increasing their axon terminal size and activity. We termed this compensation as cross-neuron plasticity, and in this study, we demonstrated that the Drosophila engulfment receptor, Draper, and the associated kinase, Shark, are required in glial cells. Surprisingly, overexpression of the Draper-I isoform boosts cross-neuron plasticity, implying that the strength of plasticity correlates with Draper signaling. Synaptic plasticity normally declines as animals age, but in our system, functional cross-neuron plasticity can be induced at different time points, whereas structural cross-neuron plasticity can only be induced at early stages. Our work uncovers a novel role for glial Draper signaling in cross-neuron plasticity that may enhance nervous system function during neurodegeneration and provides insights into how healthy bystander neurons respond to the loss of their neighboring neurons.
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24
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Golf SR, Trotter JH, Nakahara G, Südhof TC. Astrocytic Neuroligins Are Not Required for Synapse Formation or a Normal Astrocyte Cytoarchitecture. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.10.536254. [PMID: 37090508 PMCID: PMC10120619 DOI: 10.1101/2023.04.10.536254] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/25/2023]
Abstract
Astrocytes exert multifarious roles in the formation, regulation, and function of synapses in the brain, but the mechanisms involved remain unclear. Interestingly, astrocytes abundantly express neuroligins, postsynaptic adhesion molecules that bind to presynaptic neurexins. A pioneering recent study reported that loss-of-function of neuroligins in astrocytes impairs excitatory synapse formation and astrocyte morphogenesis. This study suggested a crucial synaptic function for astrocytic neuroligins but was puzzling given that constitutive neuroligin deletions do not decrease excitatory synapse numbers. Thus, we here examined the function of astrocytic neuroligins using a rigorous conditional genetic approach with deletion of all major neuroligins (Nlgn1-3) in astrocytes. Our results show that early postnatal deletion of neuroligins from astrocytes has no effect on cortical or hippocampal synapses and does not alter the cytoarchitecture of astrocytes. Thus, astrocytic neuroligins are unlikely to shape synapse formation or astrocyte development but may perform other important functions in astrocytes.
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Affiliation(s)
- Samantha R. Golf
- Dept. of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Justin H. Trotter
- Dept. of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - George Nakahara
- Dept. of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Thomas C. Südhof
- Dept. of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA 94305, USA
- Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, CA 94305, USA
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Corty MM, Coutinho-Budd J. Drosophila glia take shape to sculpt the nervous system. Curr Opin Neurobiol 2023; 79:102689. [PMID: 36822142 PMCID: PMC10023329 DOI: 10.1016/j.conb.2023.102689] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Revised: 12/19/2022] [Accepted: 01/10/2023] [Indexed: 02/23/2023]
Abstract
The importance of glial cells has become increasingly apparent over the past 20 years, yet compared to neurons we still know relatively little about these essential cells. Most critical glial cell functions are conserved in Drosophila glia, often using the same key molecular players as their vertebrate counterparts. The relative simplicity of the Drosophila nervous system, combined with a vast array of powerful genetic tools, allows us to further dissect the molecular composition and functional roles of glia in ways that would be much more cumbersome or not possible in higher vertebrate systems. Importantly, Drosophila genetics allow for in vivo manipulation, and their transparent body wall enables in vivo imaging of glia in intact animals throughout early development. Here we discuss recent advances in Drosophila glial development detailing how these cells take on their mature morphologies and interact with neurons to perform their important functional roles in the nervous system.
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Affiliation(s)
- Megan M Corty
- Vollum Institute, Oregon Health & Science University, Portland, OR, USA. https://twitter.com/@megancphd
| | - Jaeda Coutinho-Budd
- Department of Neuroscience, University of Virginia, Charlottesville, VA, USA.
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26
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Astrocyte heterogeneity and interactions with local neural circuits. Essays Biochem 2023; 67:93-106. [PMID: 36748397 PMCID: PMC10011406 DOI: 10.1042/ebc20220136] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Revised: 01/09/2023] [Accepted: 01/09/2023] [Indexed: 02/08/2023]
Abstract
Astrocytes are ubiquitous within the central nervous system (CNS). These cells possess many individual processes which extend out into the neuropil, where they interact with a variety of other cell types, including neurons at synapses. Astrocytes are now known to be active players in all aspects of the synaptic life cycle, including synapse formation and elimination, synapse maturation, maintenance of synaptic homeostasis and modulation of synaptic transmission. Traditionally, astrocytes have been studied as a homogeneous group of cells. However, recent studies have uncovered a surprising degree of heterogeneity in their development and function, suggesting that astrocytes may be matched to neurons to support local circuits. Hence, a better understanding of astrocyte heterogeneity and its implications are needed to understand brain function.
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Smith CJ. Evolutionarily conserved concepts in glial cell biology. Curr Opin Neurobiol 2023; 78:102669. [PMID: 36577179 PMCID: PMC9845142 DOI: 10.1016/j.conb.2022.102669] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Revised: 11/17/2022] [Accepted: 11/28/2022] [Indexed: 12/28/2022]
Abstract
The evolutionary conservation of glial cells has been appreciated since Ramon y Cajal and Del Rio Hortega first described the morphological features of cells in the nervous system. We now appreciate that glial cells have essential roles throughout life in most nervous systems. The field of glial cell biology has grown exponentially in the last ten years. This new wealth of knowledge has been aided by seminal findings in non-mammalian model systems. Ultimately, such concepts help us to understand glia in mammalian nervous systems. Rather than summarizing the field of glial biology, I will first briefly introduce glia in non-mammalian models systems. Then, highlight seminal findings across the glial field that utilized non-mammalian model systems to advance our understanding of the mammalian nervous system. Finally, I will call attention to some recent findings that introduce new questions about glial cell biology that will be investigated for years to come.
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Affiliation(s)
- Cody J Smith
- Department of Biological Sciences, IN, USA; The Center for Stem Cells and Regenerative Medicine, University of Notre Dame, Notre Dame, IN, USA.
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28
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Tsujioka H, Yamashita T. Utilization of ethanolamine phosphate phospholyase as a unique astrocytic marker. Front Cell Neurosci 2023; 17:1097512. [PMID: 36794261 PMCID: PMC9922850 DOI: 10.3389/fncel.2023.1097512] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Accepted: 01/10/2023] [Indexed: 01/31/2023] Open
Abstract
Astrocytes play diverse roles in the central nervous system (CNS) in both physiological and pathological conditions. Previous studies have identified many markers of astrocytes to analyze their complicated roles. Recently, closure of the critical period by mature astrocytes has been revealed, and the need for finding mature astrocyte-specific markers has been growing. We previously found that Ethanolamine phosphate phospholyase (Etnppl) was almost not expressed in the developing neonatal spinal cord, and its expression level slightly decreased after pyramidotomy in adult mice, which showed weak axonal sprouting, suggesting that its expression level negatively correlates with axonal elongation. Although the expression of Etnppl in astrocytes in adult is known, its utility as an astrocytic marker has not yet been investigated in detail. Here, we showed that Etnppl was selectively expressed in astrocytes in adult. Re-analyses using published RNA-sequencing datasets revealed changes in Etnppl expression in spinal cord injury, stroke, or systemic inflammation models. We produced high-quality monoclonal antibodies against ETNPPL and characterized ETNPPL localization in neonatal and adult mice. Expression of ETNPPL was very weak in neonatal mice, except in the ventricular and subventricular zones, and it was heterogeneously expressed in adult mice, with the highest expression in the cerebellum, olfactory bulb, and hypothalamus and the lowest in white matter. Subcellular localization of ETNPPL was dominant in the nuclei with weak expression in the cytosol in the minor population. Using the antibody, astrocytes in adult were selectively labeled in the cerebral cortex or spinal cord, and changes in astrocytes were detected in the spinal cord after pyramidotomy. ETNPPL is expressed in a subset of Gjb6 + astrocytes in the spinal cord. The monoclonal antibodies we created, as well as fundamental knowledge characterized in this study, will be valuable resources in the scientific community and will expand our understanding of astrocytes and their complicated responses in many pathological conditions in future analyses.
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Affiliation(s)
- Hiroshi Tsujioka
- Graduate School of Medicine, Osaka University, Osaka, Japan,WPI Immunology Frontier Research Center, Osaka University, Osaka, Japan,*Correspondence: Hiroshi Tsujioka,
| | - Toshihide Yamashita
- Graduate School of Medicine, Osaka University, Osaka, Japan,WPI Immunology Frontier Research Center, Osaka University, Osaka, Japan,Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan,Department of Neuro-Medical Science, Graduate School of Medicine, Osaka University, Osaka, Japan,Toshihide Yamashita,
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29
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Coulson B, Hunter I, Doran S, Parkin J, Landgraf M, Baines RA. Critical periods in Drosophila neural network development: Importance to network tuning and therapeutic potential. Front Physiol 2022; 13:1073307. [PMID: 36531164 PMCID: PMC9757492 DOI: 10.3389/fphys.2022.1073307] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Accepted: 11/23/2022] [Indexed: 02/25/2024] Open
Abstract
Critical periods are phases of heightened plasticity that occur during the development of neural networks. Beginning with pioneering work of Hubel and Wiesel, which identified a critical period for the formation of ocular dominance in mammalian visual network connectivity, critical periods have been identified for many circuits, both sensory and motor, and across phyla, suggesting a universal phenomenon. However, a key unanswered question remains why these forms of plasticity are restricted to specific developmental periods rather than being continuously present. The consequence of this temporal restriction is that activity perturbations during critical periods can have lasting and significant functional consequences for mature neural networks. From a developmental perspective, critical period plasticity might enable reproducibly robust network function to emerge from ensembles of cells, whose properties are necessarily variable and fluctuating. Critical periods also offer significant clinical opportunity. Imposed activity perturbation during these periods has shown remarkable beneficial outcomes in a range of animal models of neurological disease including epilepsy. In this review, we spotlight the recent identification of a locomotor critical period in Drosophila larva and describe how studying this model organism, because of its simplified nervous system and an almost complete wired connectome, offers an attractive prospect of understanding how activity during a critical period impacts a neuronal network.
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Affiliation(s)
- Bramwell Coulson
- Division of Neuroscience, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Science Centre, Manchester, United Kingdom
| | - Iain Hunter
- Division of Neuroscience, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Science Centre, Manchester, United Kingdom
| | - Sarah Doran
- Division of Neuroscience, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Science Centre, Manchester, United Kingdom
| | - Jill Parkin
- Division of Neuroscience, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Science Centre, Manchester, United Kingdom
| | - Matthias Landgraf
- Department of Zoology, University of Cambridge, Cambridge, United Kingdom
| | - Richard A. Baines
- Division of Neuroscience, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Science Centre, Manchester, United Kingdom
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Giachello CNG, Hunter I, Pettini T, Coulson B, Knüfer A, Cachero S, Winding M, Arzan Zarin A, Kohsaka H, Fan YN, Nose A, Landgraf M, Baines RA. Electrophysiological Validation of Monosynaptic Connectivity between Premotor Interneurons and the aCC Motoneuron in the Drosophila Larval CNS. J Neurosci 2022; 42:6724-6738. [PMID: 35868863 PMCID: PMC9435966 DOI: 10.1523/jneurosci.2463-21.2022] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2021] [Revised: 04/28/2022] [Accepted: 05/31/2022] [Indexed: 11/21/2022] Open
Abstract
The Drosophila connectome project aims to map the synaptic connectivity of entire larval and adult fly neural networks, which is essential for understanding nervous system development and function. So far, the project has produced an impressive amount of electron microscopy data that has facilitated reconstructions of specific synapses, including many in the larval locomotor circuit. While this breakthrough represents a technical tour de force, the data remain underutilized, partly because of a lack of functional validation of reconstructions. Attempts to validate connectivity posited by the connectome project, have mostly relied on behavioral assays and/or GFP reconstitution across synaptic partners (GRASP) or GCaMP imaging. While these techniques are useful, they have limited spatial or temporal resolution. Electrophysiological assays of synaptic connectivity overcome these limitations. Here, we combine patch-clamp recordings with optogenetic stimulation in male and female larvae, to test synaptic connectivity proposed by connectome reconstructions. Specifically, we use multiple driver lines to confirm that several connections between premotor interneurons and the anterior corner cell motoneuron are, as the connectome project suggests, monosynaptic. In contrast, our results also show that conclusions based on GRASP imaging may provide false-positive results regarding connectivity between cells. We also present a novel imaging tool, based on the same technology as our electrophysiology, as a favorable alternative to GRASP imaging. Finally, of eight Gal4 lines tested, five are reliably expressed in the premotor interneurons they are targeted to. Thus, our work highlights the need to confirm functional synaptic connectivity, driver line specificity, and use of appropriate genetic tools to support connectome projects.SIGNIFICANCE STATEMENT The Drosophila connectome project aims to provide a complete description of connectivity between neurons in an organism that presents experimental advantages over other models. It has reconstructed hundreds of thousands of synaptic connections of the fly larva by manual identification of anatomic landmarks present in serial section transmission electron microscopy (ssTEM) volumes of the larval CNS. We use a highly reliable electrophysiological approach to verify these connections, providing useful insight into the accuracy of work based on ssTEM. We also present a novel imaging tool for validating excitatory monosynaptic connections between cells and show that several genetic driver lines designed to target neurons of the larval connectome exhibit nonspecific and/or unreliable expression.
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Affiliation(s)
- Carlo N G Giachello
- Division of Neuroscience and Experimental Psychology, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester M13 9PT, United Kingdom
- Manchester Academic Health Science Centre, Manchester M13 9NQ, United Kingdom
| | - Iain Hunter
- Division of Neuroscience and Experimental Psychology, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester M13 9PT, United Kingdom
- Manchester Academic Health Science Centre, Manchester M13 9NQ, United Kingdom
| | - Tom Pettini
- Department of Zoology, University of Cambridge, Cambridge CB2 3EJ, United Kingdom
| | - Bramwell Coulson
- Division of Neuroscience and Experimental Psychology, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester M13 9PT, United Kingdom
- Manchester Academic Health Science Centre, Manchester M13 9NQ, United Kingdom
| | - Athene Knüfer
- Department of Zoology, University of Cambridge, Cambridge CB2 3EJ, United Kingdom
| | - Sebastian Cachero
- Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, United Kingdom
| | - Michael Winding
- Department of Zoology, University of Cambridge, Cambridge CB2 3EJ, United Kingdom
| | - Aref Arzan Zarin
- Department of Biology, Texas A&M University, College Station, Texas 77843-3258
| | - Hiroshi Kohsaka
- Graduate School of Informatics and Engineering, The University of Electro-Communications, Tokyo 182-8585, Japan
| | - Yuen Ngan Fan
- Division of Neuroscience and Experimental Psychology, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester M13 9PT, United Kingdom
- Manchester Academic Health Science Centre, Manchester M13 9NQ, United Kingdom
| | - Akinao Nose
- Department of Complexity Science and Engineering, Graduate School of Frontier Sciences, University of Tokyo, Chiba 277-8561, Japan
| | - Matthias Landgraf
- Department of Zoology, University of Cambridge, Cambridge CB2 3EJ, United Kingdom
| | - Richard A Baines
- Division of Neuroscience and Experimental Psychology, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester M13 9PT, United Kingdom
- Manchester Academic Health Science Centre, Manchester M13 9NQ, United Kingdom
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31
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Gibel-Russo R, Benacom D, Di Nardo AA. Non-Cell-Autonomous Factors Implicated in Parvalbumin Interneuron Maturation and Critical Periods. Front Neural Circuits 2022; 16:875873. [PMID: 35601531 PMCID: PMC9115720 DOI: 10.3389/fncir.2022.875873] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Accepted: 04/04/2022] [Indexed: 02/04/2023] Open
Abstract
From birth to adolescence, the brain adapts to its environmental stimuli through structural and functional remodeling of neural circuits during critical periods of heightened plasticity. They occur across modalities for proper sensory, motor, linguistic, and cognitive development. If they are disrupted by early-life adverse experiences or genetic deficiencies, lasting consequences include behavioral changes, physiological and cognitive deficits, or psychiatric illness. Critical period timing is orchestrated not only by appropriate neural activity but also by a multitude of signals that participate in the maturation of fast-spiking parvalbumin interneurons and the consolidation of neural circuits. In this review, we describe the various signaling factors that initiate critical period onset, such as BDNF, SPARCL1, or OTX2, which originate either from local neurons or glial cells or from extracortical sources such as the choroid plexus. Critical period closure is established by signals that modulate extracellular matrix and myelination, while timing and plasticity can also be influenced by circadian rhythms and by hormones and corticosteroids that affect brain oxidative stress levels or immune response. Molecular outcomes include lasting epigenetic changes which themselves can be considered signals that shape downstream cross-modal critical periods. Comprehensive knowledge of how these signals and signaling factors interplay to influence neural mechanisms will help provide an inclusive perspective on the effects of early adversity and developmental defects that permanently change perception and behavior.
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32
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Cossart R, Garel S. Step by step: cells with multiple functions in cortical circuit assembly. Nat Rev Neurosci 2022; 23:395-410. [DOI: 10.1038/s41583-022-00585-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/16/2022] [Indexed: 12/23/2022]
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33
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Bajar BT, Phi NT, Randhawa H, Akin O. Developmental neural activity requires neuron-astrocyte interactions. Dev Neurobiol 2022; 82:235-244. [PMID: 35225404 PMCID: PMC9018619 DOI: 10.1002/dneu.22870] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Revised: 12/06/2021] [Accepted: 01/12/2022] [Indexed: 11/10/2022]
Abstract
Developmental neural activity is a common feature of neural circuit assembly. Although glia have established roles in synapse development, the contribution of neuron-glia interactions to developmental activity remains largely unexplored. Here we show that astrocytes are necessary for developmental activity during synaptogenesis in Drosophila. Using wide-field epifluorescence and two-photon imaging, we show that the glia of the central nervous system participate in developmental activity with type-specific patterns of intracellular calcium dynamics. Genetic ablation of astrocytes, but not of cortex or ensheathing glia, leads to severe attenuation of neuronal activity. Similarly, inhibition of neuronal activity results in the loss of astrocyte calcium dynamics. By altering these dynamics, we show that astrocytic calcium cycles can influence neuronal activity but are not necessary per se. Taken together, our results indicate that, in addition to their recognized role in the structural maturation of synapses, astrocytes are also necessary for the function of synapses during development.
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Affiliation(s)
- Bryce T. Bajar
- Department of Biological Chemistry, Medical Scientist Training Program, Neuroscience Interdepartmental Program, David Geffen School of Medicine at UCLA, Los Angeles, CA, 90095
| | - Nguyen T. Phi
- Department of Neurobiology, David Geffen School of Medicine at UCLA, Los Angeles, CA, 90095
| | - Harpreet Randhawa
- Department of Neurobiology, David Geffen School of Medicine at UCLA, Los Angeles, CA, 90095
| | - Orkun Akin
- Department of Neurobiology, David Geffen School of Medicine at UCLA, Los Angeles, CA, 90095
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34
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Pogodalla N, Winkler B, Klämbt C. Glial Tiling in the Insect Nervous System. Front Cell Neurosci 2022; 16:825695. [PMID: 35250488 PMCID: PMC8891220 DOI: 10.3389/fncel.2022.825695] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Accepted: 01/06/2022] [Indexed: 11/30/2022] Open
Abstract
The Drosophila nervous system comprises a small number of well characterized glial cell classes. The outer surface of the central nervous system (CNS) is protected by a glial derived blood-brain barrier generated by perineurial and subperineurial glia. All neural stem cells and all neurons are engulfed by cortex glial cells. The inner neuropil region, that harbors all synapses and dendrites, is covered by ensheathing glia and infiltrated by astrocyte-like glial cells. All these glial cells show a tiled organization with an often remarkable plasticity where glial cells of one cell type invade the territory of the neighboring glial cell type upon its ablation. Here, we summarize the different glial tiling patterns and based on the different modes of cell-cell contacts we hypothesize that different molecular mechanisms underlie tiling of the different glial cell types.
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35
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Tworig JM, Feller MB. Müller Glia in Retinal Development: From Specification to Circuit Integration. Front Neural Circuits 2022; 15:815923. [PMID: 35185477 PMCID: PMC8856507 DOI: 10.3389/fncir.2021.815923] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Accepted: 12/23/2021] [Indexed: 01/21/2023] Open
Abstract
Müller glia of the retina share many features with astroglia located throughout the brain including maintenance of homeostasis, modulation of neurotransmitter spillover, and robust response to injury. Here we present the molecular factors and signaling events that govern Müller glial specification, patterning, and differentiation. Next, we discuss the various roles of Müller glia in retinal development, which include maintaining retinal organization and integrity as well as promoting neuronal survival, synaptogenesis, and phagocytosis of debris. Finally, we review the mechanisms by which Müller glia integrate into retinal circuits and actively participate in neuronal signaling during development.
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Affiliation(s)
- Joshua M. Tworig
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, United States
- *Correspondence: Joshua M. Tworig,
| | - Marla B. Feller
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, United States
- Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA, United States
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36
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Gingrich EC, Case K, Garcia ADR. A subpopulation of astrocyte progenitors defined by Sonic hedgehog signaling. Neural Dev 2022; 17:2. [PMID: 35027088 PMCID: PMC8759290 DOI: 10.1186/s13064-021-00158-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Accepted: 12/20/2021] [Indexed: 01/12/2023] Open
Abstract
BACKGROUND The molecular signaling pathway, Sonic hedgehog (Shh), is critical for the proper development of the central nervous system. The requirement for Shh signaling in neuronal and oligodendrocyte development in the developing embryo are well established. However, Shh activity is found in discrete subpopulations of astrocytes in the postnatal and adult brain. Whether Shh signaling plays a role in astrocyte development is not well understood. METHODS Here, we use a genetic inducible fate mapping approach to mark and follow a population of glial progenitor cells expressing the Shh target gene, Gli1, in the neonatal and postnatal brain. RESULTS In the neonatal brain, Gli1-expressing cells are found in the dorsolateral corner of the subventricular zone (SVZ), a germinal zone harboring astrocyte progenitor cells. Our data show that these cells give rise to half of the cortical astrocyte population, demonstrating their substantial contribution to the cellular composition of the cortex. Further, these data suggest that the cortex harbors astrocytes from different lineages. Gli1 lineage astrocytes are distributed across all cortical layers, positioning them for broad influence over cortical circuits. Finally, we show that Shh activity recurs in mature astrocytes in a lineage-independent manner, suggesting cell-type dependent roles of the pathway in driving astrocyte development and function. CONCLUSION These data identify a novel role for Shh signaling in cortical astrocyte development and support a growing body of evidence pointing to astrocyte heterogeneity.
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Affiliation(s)
- Ellen C Gingrich
- Department of Biology, Stanford University, Stanford, CA, 94305, USA
- Drexel University, 3245 Chestnut St. PISB 422, Philadelphia, PA, 19104, USA
| | - Kendra Case
- Drexel University, 3245 Chestnut St. PISB 422, Philadelphia, PA, 19104, USA
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA, 19129, USA
| | - A Denise R Garcia
- Drexel University, 3245 Chestnut St. PISB 422, Philadelphia, PA, 19104, USA.
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA, 19129, USA.
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37
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Heckman EL, Doe CQ. Presynaptic contact and activity opposingly regulate postsynaptic dendrite outgrowth. eLife 2022; 11:82093. [PMID: 36448675 PMCID: PMC9728994 DOI: 10.7554/elife.82093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Accepted: 11/29/2022] [Indexed: 12/03/2022] Open
Abstract
The organization of neural circuits determines nervous system function. Variability can arise during neural circuit development (e.g. neurite morphology, axon/dendrite position). To ensure robust nervous system function, mechanisms must exist to accommodate variation in neurite positioning during circuit formation. Previously, we developed a model system in the Drosophila ventral nerve cord to conditionally induce positional variability of a proprioceptive sensory axon terminal, and used this model to show that when we altered the presynaptic position of the sensory neuron, its major postsynaptic interneuron partner modified its dendritic arbor to match the presynaptic contact, resulting in functional synaptic input (Sales et al., 2019). Here, we investigate the cellular mechanisms by which the interneuron dendrites detect and match variation in presynaptic partner location and input strength. We manipulate the presynaptic sensory neuron by (a) ablation; (b) silencing or activation; or (c) altering its location in the neuropil. From these experiments we conclude that there are two opposing mechanisms used to establish functional connectivity in the face of presynaptic variability: presynaptic contact stimulates dendrite outgrowth locally, whereas presynaptic activity inhibits postsynaptic dendrite outgrowth globally. These mechanisms are only active during an early larval critical period for structural plasticity. Collectively, our data provide new insights into dendrite development, identifying mechanisms that allow dendrites to flexibly respond to developmental variability in presynaptic location and input strength.
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Affiliation(s)
- Emily L Heckman
- Institute of Neuroscience, Howard Hughes Medical Institute, University of OregonEugeneUnited States
| | - Chris Q Doe
- Institute of Neuroscience, Howard Hughes Medical Institute, University of OregonEugeneUnited States
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38
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DeSantis DF, Smith CJ. Tetris in the Nervous System: What Principles of Neuronal Tiling Can Tell Us About How Glia Play the Game. Front Cell Neurosci 2021; 15:734938. [PMID: 34512272 PMCID: PMC8430210 DOI: 10.3389/fncel.2021.734938] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Accepted: 08/09/2021] [Indexed: 11/14/2022] Open
Abstract
The precise organization and arrangement of neural cells is essential for nervous system functionality. Cellular tiling is an evolutionarily conserved phenomenon that organizes neural cells, ensuring non-redundant coverage of receptive fields in the nervous system. First recorded in the drawings of Ramon y Cajal more than a century ago, we now have extensive knowledge of the biochemical and molecular mechanisms that mediate tiling of neurons. The advent of live imaging techniques in both invertebrate and vertebrate model organisms has enhanced our understanding of these processes. Despite advancements in our understanding of neuronal tiling, we know relatively little about how glia, an essential non-neuronal component of the nervous system, tile and contribute to the overall spatial arrangement of the nervous system. Here, we discuss lessons learned from neurons and apply them to potential mechanisms that glial cells may use to tile, including cell diversity, contact-dependent repulsion, and chemical signaling. We also discuss open questions in the field of tiling and what new technologies need to be developed in order to better understand glial tiling.
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Affiliation(s)
- Dana F DeSantis
- Center for Stem Cells and Regenerative Medicine, University of Notre Dame, Notre Dame, IN, United States.,Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, United States
| | - Cody J Smith
- Center for Stem Cells and Regenerative Medicine, University of Notre Dame, Notre Dame, IN, United States.,Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, United States
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39
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Shi R, Kramer DA, Chen B, Shen K. A two-step actin polymerization mechanism drives dendrite branching. Neural Dev 2021; 16:3. [PMID: 34281597 PMCID: PMC8290545 DOI: 10.1186/s13064-021-00154-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2021] [Accepted: 06/14/2021] [Indexed: 11/10/2022] Open
Abstract
Background Dendrite morphogenesis plays an essential role in establishing the connectivity and receptive fields of neurons during the development of the nervous system. To generate the diverse morphologies of branched dendrites, neurons use external cues and cell surface receptors to coordinate intracellular cytoskeletal organization; however, the molecular mechanisms of how this signaling forms branched dendrites are not fully understood. Methods We performed in vivo time-lapse imaging of the PVD neuron in C. elegans in several mutants of actin regulatory proteins, such as the WAVE Regulatory Complex (WRC) and UNC-34 (homolog of Enabled/Vasodilator-stimulated phosphoprotein (Ena/VASP)). We examined the direct interaction between the WRC and UNC-34 and analyzed the localization of UNC-34 in vivo using transgenic worms expressing UNC-34 fused to GFP. Results We identify a stereotyped sequence of morphological events during dendrite outgrowth in the PVD neuron in C. elegans. Specifically, local increases in width (“swellings”) give rise to filopodia to facilitate a “rapid growth and pause” mode of growth. In unc-34 mutants, filopodia fail to form but swellings are intact. In WRC mutants, dendrite growth is largely absent, resulting from a lack of both swelling and filopodia formation. We also found that UNC-34 can directly bind to the WRC. Disrupting this binding by deleting the UNC-34 EVH1 domain prevented UNC-34 from localizing to swellings and dendrite tips, resulting in a stunted dendritic arbor and reduced filopodia outgrowth. Conclusions We propose that regulators of branched and linear F-actin cooperate to establish dendritic branches. By combining our work with existing literature, we propose that the dendrite guidance receptor DMA-1 recruits the WRC, which polymerizes branched F-actin to generate “swellings” on a mother dendrite. Then, WRC recruits the actin elongation factor UNC-34/Ena/VASP to initiate growth of a new dendritic branch from the swelling, with the help of the actin-binding protein UNC-115/abLIM. Extension of existing dendrites also proceeds via swelling formation at the dendrite tip followed by UNC-34-mediated outgrowth. Following dendrite initiation and extension, the stabilization of branches by guidance receptors further recruits WRC, resulting in an iterative process to build a complex dendritic arbor. Supplementary Information The online version contains supplementary material available at 10.1186/s13064-021-00154-0.
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Affiliation(s)
- Rebecca Shi
- Department of Biology, Stanford University, Stanford, CA, 94305, USA.,Neurosciences IDP, Stanford University, Stanford, CA, 94305, USA
| | - Daniel A Kramer
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, IA, 50011, USA
| | - Baoyu Chen
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, IA, 50011, USA
| | - Kang Shen
- Department of Biology, Stanford University, Stanford, CA, 94305, USA. .,Howard Hughes Medical Institute, Stanford University, Stanford, CA, 94305, USA.
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Abstract
Astrocytes regulate the experience-dependent remodeling of brain circuits during development
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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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Hunter I, Coulson B, Zarin AA, Baines RA. The Drosophila Larval Locomotor Circuit Provides a Model to Understand Neural Circuit Development and Function. Front Neural Circuits 2021; 15:684969. [PMID: 34276315 PMCID: PMC8282269 DOI: 10.3389/fncir.2021.684969] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Accepted: 06/09/2021] [Indexed: 11/13/2022] Open
Abstract
It is difficult to answer important questions in neuroscience, such as: "how do neural circuits generate behaviour?," because research is limited by the complexity and inaccessibility of the mammalian nervous system. Invertebrate model organisms offer simpler networks that are easier to manipulate. As a result, much of what we know about the development of neural circuits is derived from work in crustaceans, nematode worms and arguably most of all, the fruit fly, Drosophila melanogaster. This review aims to demonstrate the utility of the Drosophila larval locomotor network as a model circuit, to those who do not usually use the fly in their work. This utility is explored first by discussion of the relatively complete connectome associated with one identified interneuron of the locomotor circuit, A27h, and relating it to similar circuits in mammals. Next, it is developed by examining its application to study two important areas of neuroscience research: critical periods of development and interindividual variability in neural circuits. In summary, this article highlights the potential to use the larval locomotor network as a "generic" model circuit, to provide insight into mammalian circuit development and function.
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Affiliation(s)
- Iain Hunter
- Division of Neuroscience and Experimental Psychology, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, School of Biological Sciences, University of Manchester, Manchester, United Kingdom
| | - Bramwell Coulson
- Division of Neuroscience and Experimental Psychology, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, School of Biological Sciences, University of Manchester, Manchester, United Kingdom
| | - Aref Arzan Zarin
- Department of Biology, The Texas A&M Institute for Neuroscience, Texas A&M University, College Station, TX, United States
| | - Richard A Baines
- Division of Neuroscience and Experimental Psychology, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, School of Biological Sciences, University of Manchester, Manchester, United Kingdom
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New Tricks for an Old (Hedge)Hog: Sonic Hedgehog Regulation of Astrocyte Function. Cells 2021; 10:cells10061353. [PMID: 34070740 PMCID: PMC8228508 DOI: 10.3390/cells10061353] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Revised: 05/26/2021] [Accepted: 05/27/2021] [Indexed: 01/12/2023] Open
Abstract
The Sonic hedgehog (Shh) molecular signaling pathway is well established as a key regulator of neurodevelopment. It regulates diverse cellular behaviors, and its functions vary with respect to cell type, region, and developmental stage, reflecting the incredible pleiotropy of this molecular signaling pathway. Although it is best understood for its roles in development, Shh signaling persists into adulthood and is emerging as an important regulator of astrocyte function. Astrocytes play central roles in a broad array of nervous system functions, including synapse formation and function as well as coordination and orchestration of CNS inflammatory responses in pathological states. Neurons are the source of Shh in the adult, suggesting that Shh signaling mediates neuron-astrocyte communication, a novel role for this multifaceted pathway. Multiple roles for Shh signaling in astrocytes are increasingly being identified, including regulation of astrocyte identity, modulation of synaptic organization, and limitation of inflammation. This review discusses these novel roles for Shh signaling in regulating diverse astrocyte functions in the healthy brain and in pathology.
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Lewis S. A window of opportunity. Nat Rev Neurosci 2021; 22:324-325. [PMID: 33963311 DOI: 10.1038/s41583-021-00470-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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A critical period that shapes neuronal motor circuits. Nature 2021; 592:360-361. [PMID: 33828277 DOI: 10.1038/d41586-021-00680-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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