1
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Lago-Baldaia I, Cooper M, Seroka A, Trivedi C, Powell GT, Wilson SW, Ackerman SD, Fernandes VM. A Drosophila glial cell atlas reveals a mismatch between transcriptional and morphological diversity. PLoS Biol 2023; 21:e3002328. [PMID: 37862379 PMCID: PMC10619882 DOI: 10.1371/journal.pbio.3002328] [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: 08/13/2023] [Revised: 11/01/2023] [Accepted: 09/08/2023] [Indexed: 10/22/2023] Open
Abstract
Morphology is a defining feature of neuronal identity. Like neurons, glia display diverse morphologies, both across and within glial classes, but are also known to be morphologically plastic. Here, we explored the relationship between glial morphology and transcriptional signature using the Drosophila central nervous system (CNS), where glia are categorised into 5 main classes (outer and inner surface glia, cortex glia, ensheathing glia, and astrocytes), which show within-class morphological diversity. We analysed and validated single-cell RNA sequencing data of Drosophila glia in 2 well-characterised tissues from distinct developmental stages, containing distinct circuit types: the embryonic ventral nerve cord (VNC) (motor) and the adult optic lobes (sensory). Our analysis identified a new morphologically and transcriptionally distinct surface glial population in the VNC. However, many glial morphological categories could not be distinguished transcriptionally, and indeed, embryonic and adult astrocytes were transcriptionally analogous despite differences in developmental stage and circuit type. While we did detect extensive within-class transcriptomic diversity for optic lobe glia, this could be explained entirely by glial residence in the most superficial neuropil (lamina) and an associated enrichment for immune-related gene expression. In summary, we generated a single-cell transcriptomic atlas of glia in Drosophila, and our extensive in vivo validation revealed that glia exhibit more diversity at the morphological level than was detectable at the transcriptional level. This atlas will serve as a resource for the community to probe glial diversity and function.
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Affiliation(s)
- Inês Lago-Baldaia
- Department of Cell and Developmental Biology, University College London, London, United Kingdom
| | - Maia Cooper
- Department of Cell and Developmental Biology, University College London, London, United Kingdom
| | - Austin Seroka
- Institute of Neuroscience, Howard Hughes Medical Institute, University of Oregon, Eugene, Oregon, United States of America
| | - Chintan Trivedi
- Department of Cell and Developmental Biology, University College London, London, United Kingdom
| | - Gareth T. Powell
- Department of Cell and Developmental Biology, University College London, London, United Kingdom
| | - Stephen W. Wilson
- Department of Cell and Developmental Biology, University College London, London, United Kingdom
| | - Sarah D. Ackerman
- Department of Pathology and Immunology, Brain Immunology and Glia Center, Washington University School of Medicine, Saint Louis, Missouri, United States of America
- Department of Developmental Biology, Washington University School of Medicine, Saint Louis, Missouri, United States of America
| | - Vilaiwan M. Fernandes
- Department of Cell and Developmental Biology, University College London, London, United Kingdom
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2
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Ferreira AAG, Desplan C. An Atlas of the Developing Drosophila Visual System Glia and Subcellular mRNA Localization of Transcripts in Single Cells. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.06.552169. [PMID: 37609218 PMCID: PMC10441313 DOI: 10.1101/2023.08.06.552169] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/24/2023]
Abstract
Glial cells are essential for proper nervous system development and function. To understand glial development and function, we comprehensively annotated glial cells in a single-cell mRNA-sequencing (scRNAseq) atlas of the developing Drosophila visual system. This allowed us to study their developmental trajectories, from larval to adult stages, and to understand how specific types of glia diversify during development. For example, neuropil glia that are initially transcriptionally similar in larvae, split into ensheathing and astrocyte-like glia during pupal stages. Other glial types, such as chiasm glia change gradually during development without splitting into two cell types. The analysis of scRNA-seq allowed us to discover that the transcriptome of glial cell bodies can be distinguished from that of their broken processes. The processes contain distinct enriched mRNAs that were validated in vivo. Therefore, we have identified most glial types in the developing optic lobe and devised a computational approach to identify mRNA species that are localized to cell bodies or cellular processes.
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Affiliation(s)
| | - Claude Desplan
- Department of Biology, New York University, New York, NY, USA
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3
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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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4
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Markey KM, Saunders JC, Smuts J, von Reyn CR, Garcia ADR. Astrocyte development—More questions than answers. Front Cell Dev Biol 2023; 11:1063843. [PMID: 37051466 PMCID: PMC10083403 DOI: 10.3389/fcell.2023.1063843] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Accepted: 03/14/2023] [Indexed: 03/28/2023] Open
Abstract
The past 15–20 years has seen a remarkable shift in our understanding of astrocyte contributions to central nervous system (CNS) function. Astrocytes have emerged from the shadows of neuroscience and are now recognized as key elements in a broad array of CNS functions. Astrocytes comprise a substantial fraction of cells in the human CNS. Nevertheless, fundamental questions surrounding their basic biology remain poorly understood. While recent studies have revealed a diversity of essential roles in CNS function, from synapse formation and function to blood brain barrier maintenance, fundamental mechanisms of astrocyte development, including their expansion, migration, and maturation, remain to be elucidated. The coincident development of astrocytes and synapses highlights the need to better understand astrocyte development and will facilitate novel strategies for addressing neurodevelopmental and neurological dysfunction. In this review, we provide an overview of the current understanding of astrocyte development, focusing primarily on mammalian astrocytes and highlight outstanding questions that remain to be addressed. We also include an overview of Drosophila glial development, emphasizing astrocyte-like glia given their close anatomical and functional association with synapses. Drosophila offer an array of sophisticated molecular genetic tools and they remain a powerful model for elucidating fundamental cellular and molecular mechanisms governing astrocyte development. Understanding the parallels and distinctions between astrocyte development in Drosophila and vertebrates will enable investigators to leverage the strengths of each model system to gain new insights into astrocyte function.
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Affiliation(s)
- Kathryn M. Markey
- Department of Biology, Drexel University, Philadelphia, PA, United States
| | | | - Jana Smuts
- Department of Neurobiology and Anatomy, Drexel University, Philadelphia, PA, United States
| | - Catherine R. von Reyn
- Department of Neurobiology and Anatomy, Drexel University, Philadelphia, PA, United States
- School of Biomedical Engineering, Science and Health Systems, Drexel University, Philadelphia, PA, United States
| | - A. Denise R. Garcia
- Department of Biology, Drexel University, Philadelphia, PA, United States
- Department of Neurobiology and Anatomy, Drexel University, Philadelphia, PA, United States
- *Correspondence: A. Denise R. Garcia,
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5
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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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6
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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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7
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You S, Yu AM, Roberts MA, Joseph IJ, Jackson FR. Circadian regulation of the Drosophila astrocyte transcriptome. PLoS Genet 2021; 17:e1009790. [PMID: 34543266 PMCID: PMC8483315 DOI: 10.1371/journal.pgen.1009790] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2021] [Revised: 09/30/2021] [Accepted: 08/23/2021] [Indexed: 11/17/2022] Open
Abstract
Recent studies have demonstrated that astrocytes cooperate with neurons of the brain to mediate circadian control of many rhythmic processes including locomotor activity and sleep. Transcriptional profiling studies have described the overall rhythmic landscape of the brain, but few have employed approaches that reveal heterogeneous, cell-type specific rhythms of the brain. Using cell-specific isolation of ribosome-bound RNAs in Drosophila, we constructed the first circadian “translatome” for astrocytes. This analysis identified 293 “cycling genes” in astrocytes, most with mammalian orthologs. A subsequent behavioral genetic screen identified a number of genes whose expression is required in astrocytes for normal sleep behavior. In particular, we show that certain genes known to regulate fly innate immune responses are also required for normal sleep patterns.
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Affiliation(s)
- Samantha You
- Department of Neuroscience, Tufts Graduate School of Biomedical Sciences, Tufts University School of Medicine, Boston, Massachusetts, United States of America
| | - Alder M Yu
- Department of Biology, University of Wisconsin-La Crosse, La Crosse, Wisconsin, United States of America
| | - Mary A Roberts
- Department of Neuroscience, Tufts Graduate School of Biomedical Sciences, Tufts University School of Medicine, Boston, Massachusetts, United States of America
| | - Ivanna J Joseph
- Department of Neuroscience, Tufts Graduate School of Biomedical Sciences, Tufts University School of Medicine, Boston, Massachusetts, United States of America
| | - F Rob Jackson
- Department of Neuroscience, Tufts Graduate School of Biomedical Sciences, Tufts University School of Medicine, Boston, Massachusetts, United States of America
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8
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Choi BJ, Chen YCD, Desplan C. Building a circuit through correlated spontaneous neuronal activity in the developing vertebrate and invertebrate visual systems. Genes Dev 2021; 35:677-691. [PMID: 33888564 PMCID: PMC8091978 DOI: 10.1101/gad.348241.121] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
During the development of the vertebrate nervous systems, genetic programs assemble an immature circuit that is subsequently refined by neuronal activity evoked by external stimuli. However, prior to sensory experience, the intrinsic property of the developing nervous system also triggers correlated network-level neuronal activity, with retinal waves in the developing vertebrate retina being the best documented example. Spontaneous activity has also been found in the visual system of Drosophila Here, we compare the spontaneous activity of the developing visual system between mammalian and Drosophila and suggest that Drosophila is an emerging model for mechanistic and functional studies of correlated spontaneous activity.
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Affiliation(s)
- Ben Jiwon Choi
- Department of Biology, New York University, New York, New York 10003, USA
| | | | - Claude Desplan
- Department of Biology, New York University, New York, New York 10003, USA
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9
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Dong Q, Zavortink M, Froldi F, Golenkina S, Lam T, Cheng LY. Glial Hedgehog signalling and lipid metabolism regulate neural stem cell proliferation in Drosophila. EMBO Rep 2021; 22:e52130. [PMID: 33751817 DOI: 10.15252/embr.202052130] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Revised: 02/11/2021] [Accepted: 02/12/2021] [Indexed: 01/07/2023] Open
Abstract
The final size and function of the adult central nervous system (CNS) are determined by neuronal lineages generated by neural stem cells (NSCs) in the developing brain. In Drosophila, NSCs called neuroblasts (NBs) reside within a specialised microenvironment called the glial niche. Here, we explore non-autonomous glial regulation of NB proliferation. We show that lipid droplets (LDs) which reside within the glial niche are closely associated with the signalling molecule Hedgehog (Hh). Under physiological conditions, cortex glial Hh is autonomously required to sustain niche chamber formation. Upon FGF-mediated cortex glial overgrowth, glial Hh non-autonomously activates Hh signalling in the NBs, which in turn disrupts NB cell cycle progression and its ability to produce neurons. Glial Hh's ability to signal to NB is further modulated by lipid storage regulator lipid storage droplet-2 (Lsd-2) and de novo lipogenesis gene fatty acid synthase 1 (Fasn1). Together, our data suggest that glial-derived Hh modified by lipid metabolism mechanisms can affect the neighbouring NB's ability to proliferate and produce neurons.
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Affiliation(s)
- Qian Dong
- Peter MacCallum Cancer Centre, Parkville, Vic., Australia.,Sir Peter MacCallum Department of Oncology, University of Melbourne, Parkville, Vic., Australia
| | - Michael Zavortink
- Peter MacCallum Cancer Centre, Parkville, Vic., Australia.,Sir Peter MacCallum Department of Oncology, University of Melbourne, Parkville, Vic., Australia
| | - Francesca Froldi
- Peter MacCallum Cancer Centre, Parkville, Vic., Australia.,Sir Peter MacCallum Department of Oncology, University of Melbourne, Parkville, Vic., Australia
| | - Sofya Golenkina
- Peter MacCallum Cancer Centre, Parkville, Vic., Australia.,Sir Peter MacCallum Department of Oncology, University of Melbourne, Parkville, Vic., Australia
| | - Tammy Lam
- Peter MacCallum Cancer Centre, Parkville, Vic., Australia.,Sir Peter MacCallum Department of Oncology, University of Melbourne, Parkville, Vic., Australia
| | - Louise Y Cheng
- Peter MacCallum Cancer Centre, Parkville, Vic., Australia.,Sir Peter MacCallum Department of Oncology, University of Melbourne, Parkville, Vic., Australia.,The Department of Anatomy and Neuroscience, University of Melbourne, Parkville, Vic., Australia
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10
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Sheng L, Shields EJ, Gospocic J, Glastad KM, Ratchasanmuang P, Berger SL, Raj A, Little S, Bonasio R. Social reprogramming in ants induces longevity-associated glia remodeling. SCIENCE ADVANCES 2020; 6:eaba9869. [PMID: 32875108 PMCID: PMC7438095 DOI: 10.1126/sciadv.aba9869] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Accepted: 07/09/2020] [Indexed: 05/16/2023]
Abstract
In social insects, workers and queens arise from the same genome but display profound differences in behavior and longevity. In Harpegnathos saltator ants, adult workers can transition to a queen-like state called gamergate, which results in reprogramming of social behavior and life-span extension. Using single-cell RNA sequencing, we compared the distribution of neuronal and glial populations before and after the social transition. We found that the conversion of workers into gamergates resulted in the expansion of neuroprotective ensheathing glia. Brain injury assays revealed that activation of the damage response gene Mmp1 was weaker in old workers, where the relative frequency of ensheathing glia also declined. On the other hand, long-lived gamergates retained a larger fraction of ensheathing glia and the ability to mount a strong Mmp1 response to brain injury into old age. We also observed molecular and cellular changes suggestive of age-associated decline in ensheathing glia in Drosophila.
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Affiliation(s)
- Lihong Sheng
- Epigenetics Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
- Department of Cell and Developmental Biology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Emily J. Shields
- Epigenetics Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
- Graduate Group in Genomics and Computational Biology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Janko Gospocic
- Epigenetics Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
- Department of Cell and Developmental Biology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Karl M. Glastad
- Epigenetics Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
- Department of Cell and Developmental Biology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Puttachai Ratchasanmuang
- Department of Cell and Developmental Biology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Shelley L. Berger
- Epigenetics Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
- Department of Cell and Developmental Biology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
- Department of Genetics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Arjun Raj
- Epigenetics Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
- Department of Genetics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA
| | - Shawn Little
- Department of Cell and Developmental Biology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Roberto Bonasio
- Epigenetics Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
- Department of Cell and Developmental Biology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
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11
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Bittern J, Pogodalla N, Ohm H, Brüser L, Kottmeier R, Schirmeier S, Klämbt C. Neuron-glia interaction in the Drosophila nervous system. Dev Neurobiol 2020; 81:438-452. [PMID: 32096904 DOI: 10.1002/dneu.22737] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Revised: 02/11/2020] [Accepted: 02/24/2020] [Indexed: 12/14/2022]
Abstract
Animals are able to move and react in manifold ways to external stimuli. Thus, environmental stimuli need to be detected, information must be processed, and, finally, an output decision must be transmitted to the musculature to get the animal moving. All these processes depend on the nervous system which comprises an intricate neuronal network and many glial cells. Glial cells have an equally important contribution in nervous system function as their neuronal counterpart. Manifold roles are attributed to glia ranging from controlling neuronal cell number and axonal pathfinding to regulation of synapse formation, function, and plasticity. Glial cells metabolically support neurons and contribute to the blood-brain barrier. All of the aforementioned aspects require extensive cell-cell interactions between neurons and glial cells. Not surprisingly, many of these processes are found in all phyla executed by evolutionarily conserved molecules. Here, we review the recent advance in understanding neuron-glia interaction in Drosophila melanogaster to suggest that work in simple model organisms will shed light on the function of mammalian glial cells, too.
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Affiliation(s)
- Jonas Bittern
- Institut für Neuro- und Verhaltensbiologie, Universität Münster, Münster, Germany
| | - Nicole Pogodalla
- Institut für Neuro- und Verhaltensbiologie, Universität Münster, Münster, Germany
| | - Henrike Ohm
- Institut für Neuro- und Verhaltensbiologie, Universität Münster, Münster, Germany
| | - Lena Brüser
- Institut für Neuro- und Verhaltensbiologie, Universität Münster, Münster, Germany
| | - Rita Kottmeier
- Institut für Neuro- und Verhaltensbiologie, Universität Münster, Münster, Germany
| | - Stefanie Schirmeier
- Institut für Neuro- und Verhaltensbiologie, Universität Münster, Münster, Germany
| | - Christian Klämbt
- Institut für Neuro- und Verhaltensbiologie, Universität Münster, Münster, Germany
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12
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Hernandez E, MacNamee SE, Kaplan LR, Lance K, Garcia-Verdugo HD, Farhadi DS, Deer C, Lee SW, Oland LA. The astrocyte network in the ventral nerve cord neuropil of the Drosophila third-instar larva. J Comp Neurol 2020; 528:1683-1703. [PMID: 31909826 DOI: 10.1002/cne.24852] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Revised: 12/19/2019] [Accepted: 12/20/2019] [Indexed: 11/10/2022]
Abstract
Understanding neuronal function at the local and circuit level requires understanding astrocyte function. We have provided a detailed analysis of astrocyte morphology and territory in the Drosophila third-instar ventral nerve cord where there already exists considerable understanding of the neuronal network. Astrocyte shape varies more than previously reported; many have bilaterally symmetrical partners, many have a high percentage of their arborization in adjacent segments, and many have branches that follow structural features. Taken together, our data are consistent with, but not fully explained by, a model of a developmental growth process dominated by competitive or repulsive interactions between astrocytes. Our data suggest that the model should also include cell-autonomous aspects, as well as the use of structural features for growth. Variation in location of arborization territory for identified astrocytes was great enough that a standardized scheme of neuropil division among the six astrocytes that populate each hemi-segment is not possible at the third instar. The arborizations of the astrocytes can extend across neuronal functional domains. The ventral astrocyte in particular, whose territory can extend well into the proprioceptive region of the neuropil, has no obvious branching pattern that correlates with domains of particular sensory modalities, suggesting that the astrocyte would respond to neuronal activity in any of the sensory modalities, perhaps integrating across them. This study sets the stage for future studies that will generate a robust, functionally oriented connectome that includes both partners in neuronal circuits-the neurons and the glial cells, providing the foundation necessary for studies to elucidate neuron-glia interactions in this neuropil.
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Key Words
- RRID:Abcam Cat# ab6953, RRID:AB_955010
- RRID:BDSC Cat# 30125, RRID:BDSC_30125
- RRID:BDSC Cat# 38760, RRID:BDSC_38760
- RRID:BDSC Cat# 4775, RRID:BDSC_4775
- RRID:BDSC Cat# 5692, RRID:BDSC_5692
- RRID:BDSC Cat# 64085, RRID:BDSC_64085
- RRID:BDSC Cat# 6938, RRID:BDSC_6938
- RRID:Bio-rad Cat # MCA1360, RRID:AB_322378
- RRID:Cell Signaling Technology Cat # 3724, RRID:AB_1549585
- RRID:DSHB Cat# 1D4, RRID:AB_528235
- RRID:DSHB Cat# nc82, RRID:AB_2314866
- RRID:Jackson ImmunoResearch Labs Cat# 115-167-003, RRID:AB_2338709
- RRID:Molecular Probes Cat# 6455, RRID:AB_2314543
- RRID:Molecular Probes Cat# A-21236, RRID:AB_141725
- RRID:Novus Cat # NBP1-06712, RRID:AB_1625981
- RRID:Thermo Fisher Scientific Cat# A-11034, RRID:AB_2576217.
- glial cells
- neuron-glia interaction
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Affiliation(s)
- Ernesto Hernandez
- Department of Neuroscience, University of Arizona, Tucson, Arizona.,University of Illinois at Chicago School of Medicine, Rockford, Illinois
| | - Sarah E MacNamee
- Department of Neuroscience, University of Arizona, Tucson, Arizona.,Inscopix, Palo Alto, California
| | - Leah R Kaplan
- Department of Neuroscience, University of Arizona, Tucson, Arizona.,Consortium for Science, Policy & Outcomes, Arizona State University, Washington, DC, Washington
| | - Kim Lance
- Department of Neuroscience, University of Arizona, Tucson, Arizona
| | | | - Dara S Farhadi
- Department of Neuroscience, University of Arizona, Tucson, Arizona.,College of Medicine-Phoenix, University of Arizona, Phoenix, Arizona
| | - Christine Deer
- Department of Neuroscience, University of Arizona, Tucson, Arizona.,Research Technologies Group, Data Visualization Team, University of Arizona, University Information Technology Service, Tucson, Arizona
| | - Si W Lee
- Department of Neuroscience, University of Arizona, Tucson, Arizona
| | - Lynne A Oland
- Department of Neuroscience, University of Arizona, Tucson, Arizona
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13
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Zhou B, Zuo YX, Jiang RT. Astrocyte morphology: Diversity, plasticity, and role in neurological diseases. CNS Neurosci Ther 2019; 25:665-673. [PMID: 30929313 PMCID: PMC6515705 DOI: 10.1111/cns.13123] [Citation(s) in RCA: 174] [Impact Index Per Article: 34.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2019] [Revised: 03/05/2019] [Accepted: 03/07/2019] [Indexed: 02/05/2023] Open
Abstract
Astrocytes are the most abundant glial cells in the central nervous system (CNS) and participate in synaptic, circuit, and behavioral functions. The well‐developed protoplasmic astrocytes contain numerous processes forming well‐delineated bushy territories that overlap by as little as 5% at their boundaries. This highly complex morphology, with up to approximately 80% of the cell's membrane constituted by fine processes with dimensions on the tens of nanometer scale and high surface area to volume ratios, comes in contact with synapses, blood vessels, and other glial cells. Recent progress is challenging the conventional view that astrocytes are morphologically homogeneous throughout the brain; instead, they display circuit‐ and region‐specific morphological diversity that may contribute to the heterogeneous astrocyte‐neuron spatiotemporal interplay in different brain areas. Further, the fine structure of astrocytes is found to be highly plastic and activity‐dependent. We are beginning to understand how astrocyte structural plasticity contributes to brain functions. The change/loss of astrocyte morphology, traditionally known as a hallmark for reactive astrogliosis, is a common pathological feature in many neurological disorders. However, recent data suggest the fine structural deficits preceding reactive astrogliosis may drive disease progression. This review summarizes recent advances in astrocyte morphological diversity, plasticity, and disease‐related deficits.
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Affiliation(s)
- Bin Zhou
- Laboratory of Anesthesia and Critical Care Medicine, Department of Anesthesiology, Translational Neuroscience Center, West China Hospital, Sichuan University, Chengdu, China
| | - Yun-Xia Zuo
- Laboratory of Anesthesia and Critical Care Medicine, Department of Anesthesiology, Translational Neuroscience Center, West China Hospital, Sichuan University, Chengdu, China
| | - Ruo-Tian Jiang
- Laboratory of Anesthesia and Critical Care Medicine, Department of Anesthesiology, Translational Neuroscience Center, West China Hospital, Sichuan University, Chengdu, China
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14
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Akin O, Bajar BT, Keles MF, Frye MA, Zipursky SL. Cell-type-Specific Patterned Stimulus-Independent Neuronal Activity in the Drosophila Visual System during Synapse Formation. Neuron 2019; 101:894-904.e5. [PMID: 30711355 DOI: 10.1016/j.neuron.2019.01.008] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Revised: 10/31/2018] [Accepted: 12/28/2018] [Indexed: 12/22/2022]
Abstract
Stereotyped synaptic connections define the neural circuits of the brain. In vertebrates, stimulus-independent activity contributes to neural circuit formation. It is unknown whether this type of activity is a general feature of nervous system development. Here, we report patterned, stimulus-independent neural activity in the Drosophila visual system during synaptogenesis. Using in vivo calcium, voltage, and glutamate imaging, we found that all neurons participate in this spontaneous activity, which is characterized by brain-wide periodic active and silent phases. Glia are active in a complementary pattern. Each of the 15 of over 100 specific neuron types in the fly visual system examined exhibited a unique activity signature. The activity of neurons that are synaptic partners in the adult was highly correlated during development. We propose that this cell-type-specific activity coordinates the development of the functional circuitry of the adult brain.
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Affiliation(s)
- Orkun Akin
- Department of Biological Chemistry, Howard Hughes Medical Institute, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA.
| | - Bryce T Bajar
- Department of Biological Chemistry, Howard Hughes Medical Institute, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Mehmet F Keles
- Department of Integrative Biology and Physiology, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Mark A Frye
- Department of Integrative Biology and Physiology, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - S Lawrence Zipursky
- Department of Biological Chemistry, Howard Hughes Medical Institute, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA.
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15
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Ramon-Cañellas P, Peterson HP, Morante J. From Early to Late Neurogenesis: Neural Progenitors and the Glial Niche from a Fly's Point of View. Neuroscience 2018; 399:39-52. [PMID: 30578972 DOI: 10.1016/j.neuroscience.2018.12.014] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2018] [Revised: 12/06/2018] [Accepted: 12/12/2018] [Indexed: 12/15/2022]
Abstract
Drosophila melanogaster is an important model organism used to study the brain development of organisms ranging from insects to mammals. The central nervous system in fruit flies is formed primarily in two waves of neurogenesis, one of which occurs in the embryo and one of which occurs during larval stages. In order to understand neurogenesis, it is important to research the behavior of progenitor cells that give rise to the neural networks which make up the adult nervous system. This behavior has been shown to be influenced by different factors including interactions with other cells within the progenitor niche, or local tissue microenvironment. Glial cells form a crucial part of this niche and play an active role in the development of the brain. Although in the early years of neuroscience it was believed that glia were simply scaffolding for neurons and passive components of the nervous system, their importance is nowadays recognized. Recent discoveries in progenitors and niche cells have led to new understandings of how the developing brain shapes its diverse regions. In this review, we attempt to summarize the distinct neural progenitors and glia in the Drosophila melanogaster central nervous system, from embryo to late larval stages, and make note of homologous features in mammals. We also outline the recent advances in this field in order to define the impact that glial cells have on progenitor cell niches, and we finally emphasize the importance of communication between glia and progenitor cells for proper brain formation.
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Affiliation(s)
- Pol Ramon-Cañellas
- Instituto de Neurociencias, Consejo Superior de Investigaciones Científicas (CSIC), and Universidad Miguel Hernández (UMH), Campus de Sant Joan, Apartado 18, 03550 Sant Joan, Alicante, Spain
| | - Hannah Payette Peterson
- Instituto de Neurociencias, Consejo Superior de Investigaciones Científicas (CSIC), and Universidad Miguel Hernández (UMH), Campus de Sant Joan, Apartado 18, 03550 Sant Joan, Alicante, Spain
| | - Javier Morante
- Instituto de Neurociencias, Consejo Superior de Investigaciones Científicas (CSIC), and Universidad Miguel Hernández (UMH), Campus de Sant Joan, Apartado 18, 03550 Sant Joan, Alicante, Spain.
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16
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Yang Y, Jackson R. Astrocyte identity: evolutionary perspectives on astrocyte functions and heterogeneity. Curr Opin Neurobiol 2018; 56:40-46. [PMID: 30529823 DOI: 10.1016/j.conb.2018.11.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Revised: 11/18/2018] [Accepted: 11/21/2018] [Indexed: 10/27/2022]
Abstract
The development of new animal models, in vivo isolation approaches, and improvements in genome-wide RNA expression methods have greatly propelled molecular profiling of astrocytes and the characterization of astrocyte heterogeneity in the central nervous system (CNS). Several recent reviews have comprehensively discussed the molecular and functional diversity of mammalian astrocytes. In this brief review, we emphasize interspecies comparisons and an evolutionary perspective regarding the astro(glia) of vertebrates and invertebrates which are similar in form and function. This analysis has revealed conserved astrocyte transcriptomes in the fly, mouse and human. We also offer opinions about the pattern and origin of astrocyte heterogeneity in the CNS.
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Affiliation(s)
- Yongjie Yang
- Department of Neuroscience, Tufts University School of Medicine, 136 Harrison Ave, Boston, MA, 02111, United States; Sackler School of Biomedical Sciences, Tufts University, 145 Harrison Ave, Boston, MA, 02111, United States.
| | - Rob Jackson
- Department of Neuroscience, Tufts University School of Medicine, 136 Harrison Ave, Boston, MA, 02111, United States; Sackler School of Biomedical Sciences, Tufts University, 145 Harrison Ave, Boston, MA, 02111, United States.
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Yildirim K, Petri J, Kottmeier R, Klämbt C. Drosophila glia: Few cell types and many conserved functions. Glia 2018; 67:5-26. [DOI: 10.1002/glia.23459] [Citation(s) in RCA: 75] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Revised: 04/25/2018] [Accepted: 05/04/2018] [Indexed: 12/20/2022]
Affiliation(s)
- Kerem Yildirim
- Institute for Neuro and Behavioral Biology; University of Münster; Badestraße 9, 48149 Münster Germany
| | - Johanna Petri
- Institute for Neuro and Behavioral Biology; University of Münster; Badestraße 9, 48149 Münster Germany
| | - Rita Kottmeier
- Institute for Neuro and Behavioral Biology; University of Münster; Badestraße 9, 48149 Münster Germany
| | - Christian Klämbt
- Institute for Neuro and Behavioral Biology; University of Münster; Badestraße 9, 48149 Münster Germany
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18
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Schiweck J, Eickholt BJ, Murk K. Important Shapeshifter: Mechanisms Allowing Astrocytes to Respond to the Changing Nervous System During Development, Injury and Disease. Front Cell Neurosci 2018; 12:261. [PMID: 30186118 PMCID: PMC6111612 DOI: 10.3389/fncel.2018.00261] [Citation(s) in RCA: 117] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Accepted: 07/31/2018] [Indexed: 12/30/2022] Open
Abstract
Astrocytes are the most prevalent glial cells in the brain. Historically considered as “merely supporting” neurons, recent research has shown that astrocytes actively participate in a large variety of central nervous system (CNS) functions including synaptogenesis, neuronal transmission and synaptic plasticity. During disease and injury, astrocytes efficiently protect neurons by various means, notably by sealing them off from neurotoxic factors and repairing the blood-brain barrier. Their ramified morphology allows them to perform diverse tasks by interacting with synapses, blood vessels and other glial cells. In this review article, we provide an overview of how astrocytes acquire their complex morphology during development. We then move from the developing to the mature brain, and review current research on perisynaptic astrocytic processes, with a particular focus on how astrocytes engage synapses and modulate their formation and activity. Comprehensive changes have been reported in astrocyte cell shape in many CNS pathologies. Factors influencing these morphological changes are summarized in the context of brain pathologies, such as traumatic injury and degenerative conditions. We provide insight into the molecular, cellular and cytoskeletal machinery behind these shape changes which drive the dynamic remodeling in astrocyte morphology during injury and the development of pathologies.
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Affiliation(s)
- Juliane Schiweck
- Institute for Biochemistry, Charité Universitätsmedizin Berlin, Berlin, Germany
| | - Britta J Eickholt
- Institute for Biochemistry, Charité Universitätsmedizin Berlin, Berlin, Germany
| | - Kai Murk
- Institute for Biochemistry, Charité Universitätsmedizin Berlin, Berlin, Germany
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Ren Q, Awasaki T, Wang YC, Huang YF, Lee T. Lineage-guided Notch-dependent gliogenesis by Drosophila multi-potent progenitors. Development 2018; 145:dev.160127. [PMID: 29764857 DOI: 10.1242/dev.160127] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Accepted: 05/08/2018] [Indexed: 12/27/2022]
Abstract
Macroglial cells in the central nervous system exhibit regional specialization and carry out region-specific functions. Diverse glial cells arise from specific progenitors in specific spatiotemporal patterns. This raises an interesting possibility that glial precursors with distinct developmental fates exist that govern region-specific gliogenesis. Here, we have mapped the glial progeny produced by the Drosophila type II neuroblasts, which, like vertebrate radial glia cells, yield both neurons and glia via intermediate neural progenitors (INPs). Distinct type II neuroblasts produce different characteristic sets of glia. A single INP can make both astrocyte-like and ensheathing glia, which co-occupy a relatively restrictive subdomain. Blocking apoptosis uncovers further lineage distinctions in the specification, proliferation and survival of glial precursors. Both the switch from neurogenesis to gliogenesis and the subsequent glial expansion depend on Notch signaling. Taken together, lineage origins preconfigure the development of individual glial precursors with involvement of serial Notch actions in promoting gliogenesis.
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Affiliation(s)
- Qingzhong Ren
- Howard Hughes Medical Institute, Janelia Research Campus, 19700 Helix Drive, Ashburn, VA 20147, USA
| | - Takeshi Awasaki
- Howard Hughes Medical Institute, Janelia Research Campus, 19700 Helix Drive, Ashburn, VA 20147, USA
| | - Yu-Chun Wang
- Howard Hughes Medical Institute, Janelia Research Campus, 19700 Helix Drive, Ashburn, VA 20147, USA
| | - Yu-Fen Huang
- Howard Hughes Medical Institute, Janelia Research Campus, 19700 Helix Drive, Ashburn, VA 20147, USA
| | - Tzumin Lee
- Howard Hughes Medical Institute, Janelia Research Campus, 19700 Helix Drive, Ashburn, VA 20147, USA
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20
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Krzeptowski W, Walkowicz L, Płonczyńska A, Górska-Andrzejak J. Different Levels of Expression of the Clock Protein PER and the Glial Marker REPO in Ensheathing and Astrocyte-Like Glia of the Distal Medulla of Drosophila Optic Lobe. Front Physiol 2018; 9:361. [PMID: 29695973 PMCID: PMC5904279 DOI: 10.3389/fphys.2018.00361] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Accepted: 03/23/2018] [Indexed: 12/31/2022] Open
Abstract
Circadian plasticity of the visual system of Drosophila melanogaster depends on functioning of both the neuronal and glial oscillators. The clock function of the former is already quite well-recognized. The latter, however, is much less known and documented. In this study we focus on the glial oscillators that reside in the distal part of the second visual neuropil, medulla (dMnGl), in vicinity of the PIGMENT-DISPERSING FACTOR (PDF) releasing terminals of the circadian clock ventral Lateral Neurons (LNvs). We reveal the heterogeneity of the dMnGl, which express the clock protein PERIOD (PER) and the pan-glial marker REVERSED POLARITY (REPO) at higher (P1) or lower (P2) levels. We show that the cells with stronger expression of PER display also stronger expression of REPO, and that the number of REPO-P1 cells is bigger during the day than during the night. Using a combination of genetic markers and immunofluorescent labeling with anti PER and REPO Abs, we have established that the P1 and P2 cells can be associated with two different types of the dMnGl, the ensheathing (EnGl), and the astrocyte-like glia (ALGl). Surprisingly, the EnGl belong to the P1 cells, whereas the ALGl, previously reported to play the main role in the circadian rhythms, display the characteristics of the P2 cells (express very low level of PER and low level of REPO). Next to the EnGl and ALGl we have also observed another type of cells in the distal medulla that express PER and REPO, although at very low levels. Based on their morphology we have identified them as the T1 interneurons. Our study reveals the complexity of the distal medulla circadian network, which appears to consist of different types of glial and neuronal peripheral clocks, displaying molecular oscillations of higher (EnGl) and lower (ALGl and T1) amplitudes.
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Affiliation(s)
- Wojciech Krzeptowski
- Department of Cell Biology and Imaging, Institute of Zoology and Biomedical Research, Jagiellonian University, Krakow, Poland
| | - Lucyna Walkowicz
- Department of Cell Biology and Imaging, Institute of Zoology and Biomedical Research, Jagiellonian University, Krakow, Poland
| | - Alicja Płonczyńska
- Department of Cell Biology and Imaging, Institute of Zoology and Biomedical Research, Jagiellonian University, Krakow, Poland
| | - Jolanta Górska-Andrzejak
- Department of Cell Biology and Imaging, Institute of Zoology and Biomedical Research, Jagiellonian University, Krakow, Poland
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21
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Plazaola-Sasieta H, Fernández-Pineda A, Zhu Q, Morey M. Untangling the wiring of the Drosophila visual system: developmental principles and molecular strategies. J Neurogenet 2017; 31:231-249. [DOI: 10.1080/01677063.2017.1391249] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Haritz Plazaola-Sasieta
- Department of Genetics, Microbiology and Statistics; School of Biology and Institute of Biomedicine of the University of Barcelona (IBUB), University of Barcelona, Barcelona, Spain
| | - Alejandra Fernández-Pineda
- Department of Genetics, Microbiology and Statistics; School of Biology and Institute of Biomedicine of the University of Barcelona (IBUB), University of Barcelona, Barcelona, Spain
| | - Qi Zhu
- Department of Genetics, Microbiology and Statistics; School of Biology and Institute of Biomedicine of the University of Barcelona (IBUB), University of Barcelona, Barcelona, Spain
| | - Marta Morey
- Department of Genetics, Microbiology and Statistics; School of Biology and Institute of Biomedicine of the University of Barcelona (IBUB), University of Barcelona, Barcelona, Spain
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