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Vaikakkara Chithran A, Allan DW, O'Connor TP. Adult expression of the cell adhesion protein Fasciclin 3 is required for the maintenance of adult olfactory interneurons. J Cell Sci 2024; 137:jcs261759. [PMID: 38934299 DOI: 10.1242/jcs.261759] [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: 10/30/2023] [Accepted: 05/20/2024] [Indexed: 06/28/2024] Open
Abstract
The proper functioning of the nervous system is dependent on the establishment and maintenance of intricate networks of neurons that form functional neural circuits. Once neural circuits are assembled during development, a distinct set of molecular programs is likely required to maintain their connectivity throughout the lifetime of the organism. Here, we demonstrate that Fasciclin 3 (Fas3), an axon guidance cell adhesion protein, is necessary for the maintenance of the olfactory circuit in adult Drosophila. We utilized the TARGET system to spatiotemporally knockdown Fas3 in selected populations of adult neurons. Our findings show that Fas3 knockdown results in the death of olfactory circuit neurons and reduced survival of adults. We also demonstrated that Fas3 knockdown activates caspase-3-mediated cell death in olfactory local interneurons, which can be rescued by overexpressing baculovirus p35, an anti-apoptotic protein. This work adds to the growing set of evidence indicating a crucial role for axon guidance proteins in the maintenance of neuronal circuits in adults.
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Affiliation(s)
- Aarya Vaikakkara Chithran
- Graduate Program in Neuroscience, 3402-2215 Wesbrook Mall, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
- Department of Cellular and Physiological Sciences, 2350 Health Sciences Mall, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Douglas W Allan
- Department of Cellular and Physiological Sciences, 2350 Health Sciences Mall, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
- Djavad Mowafaghian Centre for Brain Health, 2215 Wesbrook Mall, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Timothy P O'Connor
- Department of Cellular and Physiological Sciences, 2350 Health Sciences Mall, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
- Djavad Mowafaghian Centre for Brain Health, 2215 Wesbrook Mall, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
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2
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Waller TJ, Collins CA. Opposing roles of Fos, Raw, and SARM1 in the regulation of axonal degeneration and synaptic structure. Front Cell Neurosci 2023; 17:1283995. [PMID: 38099151 PMCID: PMC10719852 DOI: 10.3389/fncel.2023.1283995] [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: 08/27/2023] [Accepted: 10/30/2023] [Indexed: 12/17/2023] Open
Abstract
Introduction The degeneration of injured axons is driven by conserved molecules, including the sterile armadillo TIR domain-containing protein SARM1, the cJun N-terminal kinase JNK, and regulators of these proteins. These molecules are also implicated in the regulation of synapse development though the mechanistic relationship of their functions in degeneration vs. development is poorly understood. Results and discussion Here, we uncover disparate functional relationships between SARM1 and the transmembrane protein Raw in the regulation of Wallerian degeneration and synaptic growth in motoneurons of Drosophila melanogaster. Our genetic data suggest that Raw antagonizes the downstream output MAP kinase signaling mediated by Drosophila SARM1 (dSarm). This relationship is revealed by dramatic synaptic overgrowth phenotypes at the larval neuromuscular junction when motoneurons are depleted for Raw or overexpress dSarm. While Raw antagonizes the downstream output of dSarm to regulate synaptic growth, it shows an opposite functional relationship with dSarm for axonal degeneration. Loss of Raw leads to decreased levels of dSarm in axons and delayed axonal degeneration that is rescued by overexpression of dSarm, supporting a model that Raw promotes the activation of dSarm in axons. However, inhibiting Fos also decreases dSarm levels in axons but has the opposite outcome of enabling Wallerian degeneration. The combined genetic data suggest that Raw, dSarm, and Fos influence each other's functions through multiple points of regulation to control the structure of synaptic terminals and the resilience of axons to degeneration.
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Affiliation(s)
- Thomas J. Waller
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI, United States
| | - Catherine A. Collins
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI, United States
- Department of Neurosciences, Case Western Reserve University, Cleveland, OH, United States
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3
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Zhao H, Liu R, Wang L, Tang F, Chen W, Liu YN. Artificial Macrophage with Hierarchical Nanostructure for Biomimetic Reconstruction of Antitumor Immunity. NANO-MICRO LETTERS 2023; 15:216. [PMID: 37737506 PMCID: PMC10516848 DOI: 10.1007/s40820-023-01193-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Accepted: 08/27/2023] [Indexed: 09/23/2023]
Abstract
Artificial cells are constructed from synthetic materials to imitate the biological functions of natural cells. By virtue of nanoengineering techniques, artificial cells with designed biomimetic functions provide alternatives to natural cells, showing vast potential for biomedical applications. Especially in cancer treatment, the deficiency of immunoactive macrophages results in tumor progression and immune resistance. To overcome the limitation, a BaSO4@ZIF-8/transferrin (TRF) nanomacrophage (NMΦ) is herein constructed as an alternative to immunoactive macrophages. Alike to natural immunoactive macrophages, NMΦ is stably retained in tumors through the specific affinity of TRF to tumor cells. Zn2+ as an "artificial cytokine" is then released from the ZIF-8 layer of NMΦ under tumor microenvironment. Similar as proinflammatory cytokines, Zn2+ can trigger cell anoikis to expose tumor antigens, which are selectively captured by the BaSO4 cavities. Therefore, the hierarchical nanostructure of NMΦs allows them to mediate immunogenic death of tumor cells and subsequent antigen capture for T cell activation to fabricate long-term antitumor immunity. As a proof-of-concept, the NMΦ mimics the biological functions of macrophage, including tumor residence, cytokine release, antigen capture and immune activation, which is hopeful to provide a paradigm for the design and biomedical applications of artificial cells.
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Affiliation(s)
- Henan Zhao
- Hunan Provincial Key Laboratory of Micro & Nano Materials Interface Science, College of Chemistry and Chemical Engineering, Central South University, Changsha, 410083, Hunan, People's Republic of China
| | - Renyu Liu
- Xiangya Hospital, Central South University, Changsha, 410008, Hunan, People's Republic of China
| | - Liqiang Wang
- Henan Province Industrial Technology Research Institute of Resources and Materials, School of Material Science and Engineering, Zhengzhou University, Zhengzhou, 450001, Henan, People's Republic of China
| | - Feiying Tang
- College of Chemical Engineering, Xiangtan University, Xiangtan, 411105, Hunan, People's Republic of China
| | - Wansong Chen
- Hunan Provincial Key Laboratory of Micro & Nano Materials Interface Science, College of Chemistry and Chemical Engineering, Central South University, Changsha, 410083, Hunan, People's Republic of China.
| | - You-Nian Liu
- Hunan Provincial Key Laboratory of Micro & Nano Materials Interface Science, College of Chemistry and Chemical Engineering, Central South University, Changsha, 410083, Hunan, People's Republic of China.
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4
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Xie C, Xiang S, Shen C, Peng X, Kang J, Li Y, Cheng W, He S, Bobou M, Broulidakis MJ, van Noort BM, Zhang Z, Robinson L, Vaidya N, Winterer J, Zhang Y, King S, Banaschewski T, Barker GJ, Bokde ALW, Bromberg U, Büchel C, Flor H, Grigis A, Garavan H, Gowland P, Heinz A, Ittermann B, Lemaître H, Martinot JL, Martinot MLP, Nees F, Orfanos DP, Paus T, Poustka L, Fröhner JH, Schmidt U, Sinclair J, Smolka MN, Stringaris A, Walter H, Whelan R, Desrivières S, Sahakian BJ, Robbins TW, Schumann G, Jia T, Feng J. A shared neural basis underlying psychiatric comorbidity. Nat Med 2023; 29:1232-1242. [PMID: 37095248 PMCID: PMC10202801 DOI: 10.1038/s41591-023-02317-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Accepted: 03/20/2023] [Indexed: 04/26/2023]
Abstract
Recent studies proposed a general psychopathology factor underlying common comorbidities among psychiatric disorders. However, its neurobiological mechanisms and generalizability remain elusive. In this study, we used a large longitudinal neuroimaging cohort from adolescence to young adulthood (IMAGEN) to define a neuropsychopathological (NP) factor across externalizing and internalizing symptoms using multitask connectomes. We demonstrate that this NP factor might represent a unified, genetically determined, delayed development of the prefrontal cortex that further leads to poor executive function. We also show this NP factor to be reproducible in multiple developmental periods, from preadolescence to early adulthood, and generalizable to the resting-state connectome and clinical samples (the ADHD-200 Sample and the Stratify Project). In conclusion, we identify a reproducible and general neural basis underlying symptoms of multiple mental health disorders, bridging multidimensional evidence from behavioral, neuroimaging and genetic substrates. These findings may help to develop new therapeutic interventions for psychiatric comorbidities.
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Affiliation(s)
- Chao Xie
- Institute of Science and Technology for Brain-Inspired Intelligence, Fudan University, Shanghai, China
- Key Laboratory of Computational Neuroscience and Brain-Inspired Intelligence (Fudan University), Ministry of Education, Shanghai, China
| | - Shitong Xiang
- Institute of Science and Technology for Brain-Inspired Intelligence, Fudan University, Shanghai, China
- Key Laboratory of Computational Neuroscience and Brain-Inspired Intelligence (Fudan University), Ministry of Education, Shanghai, China
| | - Chun Shen
- Institute of Science and Technology for Brain-Inspired Intelligence, Fudan University, Shanghai, China
- Key Laboratory of Computational Neuroscience and Brain-Inspired Intelligence (Fudan University), Ministry of Education, Shanghai, China
| | - Xuerui Peng
- Faculty of Psychology, Technische Universität Dresden, Dresden, Germany
| | - Jujiao Kang
- Institute of Science and Technology for Brain-Inspired Intelligence, Fudan University, Shanghai, China
- Key Laboratory of Computational Neuroscience and Brain-Inspired Intelligence (Fudan University), Ministry of Education, Shanghai, China
| | - Yuzhu Li
- Institute of Science and Technology for Brain-Inspired Intelligence, Fudan University, Shanghai, China
- Key Laboratory of Computational Neuroscience and Brain-Inspired Intelligence (Fudan University), Ministry of Education, Shanghai, China
| | - Wei Cheng
- Institute of Science and Technology for Brain-Inspired Intelligence, Fudan University, Shanghai, China
- Key Laboratory of Computational Neuroscience and Brain-Inspired Intelligence (Fudan University), Ministry of Education, Shanghai, China
| | - Shiqi He
- Institute of Science and Technology for Brain-Inspired Intelligence, Fudan University, Shanghai, China
- School of Health Sciences, The University of Manchester, Manchester, UK
| | - Marina Bobou
- Social Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
| | - M John Broulidakis
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, UK
| | | | - Zuo Zhang
- Social Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
| | - Lauren Robinson
- Department of Psychological Medicine, Section for Eating Disorders, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
- South London and Maudsley NHS Foundation Trust, London, UK
| | - Nilakshi Vaidya
- Department of Psychiatry and Neurosciences, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Jeanne Winterer
- Department of Psychiatry and Neurosciences, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
- Department of Education and Psychology, Freie Universität Berlin, Berlin, Germany
| | - Yuning Zhang
- Psychology Department, University of Southampton, Southampton, UK
| | - Sinead King
- Social Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
- School of Medicine, Center for Neuroimaging, Cognition and Genomics, National University of Ireland (NUI) Galway, Galway, Ireland
| | - Tobias Banaschewski
- Department of Child and Adolescent Psychiatry and Psychotherapy, Central Institute of Mental Health, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Gareth J Barker
- Department of Neuroimaging, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
| | - Arun L W Bokde
- Discipline of Psychiatry, School of Medicine and Trinity College Institute of Neuroscience, Trinity College Dublin, Dublin, Ireland
| | - Uli Bromberg
- University Medical Centre Hamburg-Eppendorf, Hamburg, Germany
| | | | - Herta Flor
- Institute of Cognitive and Clinical Neuroscience, Central Institute of Mental Health, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
- Department of Psychology, School of Social Sciences, University of Mannheim, Mannheim, Germany
| | - Antoine Grigis
- NeuroSpin, C.E.A., Université Paris-Saclay, Gif-sur-Yvette, France
| | - Hugh Garavan
- Departments of Psychiatry and Psychology, University of Vermont, Burlington, VT, USA
| | - Penny Gowland
- Sir Peter Mansfield Imaging Centre School of Physics and Astronomy, University of Nottingham, Nottingham, UK
| | - Andreas Heinz
- Department of Psychiatry and Neurosciences, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Bernd Ittermann
- Physikalisch-Technische Bundesanstalt (PTB), Braunschweig and Berlin, Germany
| | - Hervé Lemaître
- Institut des Maladies Neurodégénératives, UMR 5293, CNRS, CEA, Université de Bordeaux, Bordeaux, France
| | - Jean-Luc Martinot
- Institut National de la Santé et de la Recherche Médicale, INSERM U1299 'Trajectoires développementales en psychiatrie', Université Paris-Saclay, Ecole Normale supérieure Paris-Saclay, CNRS UMR9010, Centre Borelli, Gif-sur-Yvette, France
| | - Marie-Laure Paillère Martinot
- Institut National de la Santé et de la Recherche Médicale, INSERM U1299 'Trajectoires développementales en psychiatrie', Université Paris-Saclay, Ecole Normale supérieure Paris-Saclay, CNRS UMR9010, Centre Borelli, Gif-sur-Yvette, France
- AP-HP, Sorbonne Université, Department of Child and Adolescent Psychiatry, Pitié-Salpêtrière Hospital, Paris, France
| | - Frauke Nees
- Department of Child and Adolescent Psychiatry and Psychotherapy, Central Institute of Mental Health, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
- Institute of Cognitive and Clinical Neuroscience, Central Institute of Mental Health, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
- Institute of Medical Psychology and Medical Sociology, University Medical Center Schleswig-Holstein, Kiel University, Kiel, Germany
| | | | - Tomáš Paus
- Department of Psychiatry and Neuroscience and Centre Hospitalier Universitaire Sainte-Justine, University of Montreal, Quebec, Canada
| | - Luise Poustka
- Department of Child and Adolescent Psychiatry and Psychotherapy, University Medical Centre Göttingen, Göttingen, Germany
| | - Juliane H Fröhner
- Department of Psychiatry and Neuroimaging Center, Technische Universität Dresden, Dresden, Germany
| | - Ulrike Schmidt
- Department of Psychological Medicine, Section for Eating Disorders, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
- South London and Maudsley NHS Foundation Trust, London, UK
| | - Julia Sinclair
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, UK
| | - Michael N Smolka
- Department of Psychiatry and Neuroimaging Center, Technische Universität Dresden, Dresden, Germany
| | - Argyris Stringaris
- Division of Psychiatry and Department of Clinical, Educational & Health Psychology, University College London, London, UK
| | - Henrik Walter
- Department of Psychiatry and Neurosciences, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Robert Whelan
- School of Psychology and Global Brain Health Institute, Trinity College Dublin, Dublin, Ireland
| | - Sylvane Desrivières
- Social Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
| | - Barbara J Sahakian
- Institute of Science and Technology for Brain-Inspired Intelligence, Fudan University, Shanghai, China
- Department of Psychiatry and Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge, UK
| | - Trevor W Robbins
- Institute of Science and Technology for Brain-Inspired Intelligence, Fudan University, Shanghai, China
- Department of Psychology and Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge, UK
| | - Gunter Schumann
- Institute of Science and Technology for Brain-Inspired Intelligence, Fudan University, Shanghai, China
- Department of Psychiatry and Neurosciences, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
- Department of Sports and Health Sciences, University of Potsdam, Potsdam, Germany
- PONS Centre, Institute for Science and Technology of Brain-inspired Intelligence (ISTBI), Fudan University, Shanghai, China
| | - Tianye Jia
- Institute of Science and Technology for Brain-Inspired Intelligence, Fudan University, Shanghai, China.
- Key Laboratory of Computational Neuroscience and Brain-Inspired Intelligence (Fudan University), Ministry of Education, Shanghai, China.
- Social Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK.
| | - Jianfeng Feng
- Institute of Science and Technology for Brain-Inspired Intelligence, Fudan University, Shanghai, China
- Key Laboratory of Computational Neuroscience and Brain-Inspired Intelligence (Fudan University), Ministry of Education, Shanghai, China
- School of Mathematical Sciences and Centre for Computational Systems Biology, Fudan University, Shanghai, China
- Department of Computer Science, University of Warwick, Coventry, UK
- Fudan ISTBI-ZJNU Algorithm Centre for Brain-inspired Intelligence, Zhejiang Normal University, Jinhua, China
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5
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Marmor-Kollet N, Berkun V, Cummings G, Keren-Shaul H, David E, Addadi Y, Schuldiner O. Actin-dependent astrocytic infiltration is a key step for axon defasciculation during remodeling. Cell Rep 2023; 42:112117. [PMID: 36790930 PMCID: PMC9989824 DOI: 10.1016/j.celrep.2023.112117] [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: 12/15/2021] [Revised: 10/17/2022] [Accepted: 01/28/2023] [Indexed: 02/16/2023] Open
Abstract
Astrocytes are essential for synapse formation, maturation, and plasticity; however, their function during developmental neuronal remodeling is largely unknown. To identify astrocytic molecules required for axon pruning of mushroom body (MB) γ neurons in Drosophila, we profiled astrocytes before (larva) and after (adult) remodeling. Focusing on genes enriched in larval astrocytes, we identified 12 astrocytic genes that are required for axon pruning, including the F-actin regulators Actin-related protein 2/3 complex, subunit 1 (Arpc1) and formin3 (form3). Interestingly, perturbing astrocytic actin dynamics does not affect their gross morphology, migration, or transforming growth factor β (TGF-β) secretion. In contrast, actin dynamics is required for astrocyte infiltration into the axon bundle at the onset of pruning. Remarkably, decreasing axonal adhesion facilitates infiltration by Arpc1 knockdown (KD) astrocytes and promotes axon pruning. Conversely, increased axonal adhesion reduces lobe infiltration by wild-type (WT) astrocytes. Together, our findings suggest that actin-dependent astrocytic infiltration is a key step in axon pruning, thus promoting our understanding of neuron-glia interactions during remodeling.
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Affiliation(s)
- Neta Marmor-Kollet
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot 7610001, Israel; Department of Molecular Neuroscience, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Victoria Berkun
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Gideon Cummings
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Hadas Keren-Shaul
- Department of Immunology, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Eyal David
- Department of Immunology, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Yoseph Addadi
- Weizmann Institute of Science, Life Sciences Core Facilities, Rehovot 7610001, Israel
| | - Oren Schuldiner
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot 7610001, Israel; Department of Molecular Neuroscience, Weizmann Institute of Science, Rehovot 7610001, Israel.
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6
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Karkali K, Saunders TE, Panayotou G, Martín-Blanco E. JNK signaling in pioneer neurons organizes ventral nerve cord architecture in Drosophila embryos. Nat Commun 2023; 14:675. [PMID: 36750572 PMCID: PMC9905486 DOI: 10.1038/s41467-023-36388-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Accepted: 01/30/2023] [Indexed: 02/09/2023] Open
Abstract
Morphogenesis of the Central Nervous System (CNS) is a complex process that obeys precise architectural rules. Yet, the mechanisms dictating these rules remain unknown. Analyzing morphogenesis of the Drosophila embryo Ventral Nerve Cord (VNC), we observe that a tight control of JNK signaling is essential for attaining the final VNC architecture. JNK signaling in a specific subset of pioneer neurons autonomously regulates the expression of Fasciclin 2 (Fas 2) and Neurexin IV (Nrx IV) adhesion molecules, probably via the transcription factor zfh1. Interfering at any step in this cascade affects fasciculation along pioneer axons, leading to secondary cumulative scaffolding defects during the structural organization of the axonal network. The global disorder of architectural landmarks ultimately influences nervous system condensation. In summary, our data point to JNK signaling in a subset of pioneer neurons as a key element underpinning VNC architecture, revealing critical milestones on the mechanism of control of its structural organization.
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Affiliation(s)
- Katerina Karkali
- Instituto de Biología Molecular de Barcelona (CSIC), Parc Cientific de Barcelona, Baldiri Reixac 10-12, 08028, Barcelona, Spain.,Mechanobiology Institute and Department of Biological Sciences, 5 Engineering Drive 1, National University of Singapore, Singapore, 117411, Singapore.,BSRC Alexander Fleming, 34 Fleming Street, 16672, Vari, Greece
| | - Timothy E Saunders
- Mechanobiology Institute and Department of Biological Sciences, 5 Engineering Drive 1, National University of Singapore, Singapore, 117411, Singapore.,Division of Biomedical Sciences, Warwick Medical School, University of Warwick, Coventry, CV4 7AL, UK
| | | | - Enrique Martín-Blanco
- Instituto de Biología Molecular de Barcelona (CSIC), Parc Cientific de Barcelona, Baldiri Reixac 10-12, 08028, Barcelona, Spain. .,Mechanobiology Institute and Department of Biological Sciences, 5 Engineering Drive 1, National University of Singapore, Singapore, 117411, Singapore.
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7
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Lin S. The making of the Drosophila mushroom body. Front Physiol 2023; 14:1091248. [PMID: 36711013 PMCID: PMC9880076 DOI: 10.3389/fphys.2023.1091248] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2022] [Accepted: 01/02/2023] [Indexed: 01/14/2023] Open
Abstract
The mushroom body (MB) is a computational center in the Drosophila brain. The intricate neural circuits of the mushroom body enable it to store associative memories and process sensory and internal state information. The mushroom body is composed of diverse types of neurons that are precisely assembled during development. Tremendous efforts have been made to unravel the molecular and cellular mechanisms that build the mushroom body. However, we are still at the beginning of this challenging quest, with many key aspects of mushroom body assembly remaining unexplored. In this review, I provide an in-depth overview of our current understanding of mushroom body development and pertinent knowledge gaps.
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8
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Xu W, Kong W, Gao Z, Huang E, Xie W, Wang S, Rui M. Establishment of a novel axon pruning model of Drosophila motor neuron. Biol Open 2023; 12:286282. [PMID: 36606515 PMCID: PMC9838636 DOI: 10.1242/bio.059535] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Accepted: 11/30/2022] [Indexed: 01/07/2023] Open
Abstract
Developmental neuronal pruning is a process by which neurons selectively remove excessive or unnecessary neurite without causing neuronal death. Importantly, this process is widely used for the refinement of neural circuits in both vertebrates and invertebrates, and may also contribute to the pathogenesis of neuropsychiatric disorders, such as autism and schizophrenia. In the peripheral nervous system (PNS), class IV dendritic arborization (da) sensory neurons of Drosophila, selectively remove the dendrites without losing their somas and axons, while the dendrites and axons of mushroom body (MB) γ neuron in the central nervous system (CNS) are eliminated by localized fragmentation during metamorphosis. Alternatively, dendrite pruning of ddaC neurons is usually investigated via live-cell imaging, while dissection and fixation are currently used for evaluating MB γ neuron axon pruning. Thus, an excellent model system to assess axon specific pruning directly via live-cell imaging remains elusive. Here, we report that the Drosophila motor neuron offers a unique advantage for studying axon pruning. Interestingly, we uncover that long-range projecting axon bundle from soma at ventral nerve cord (VNC), undergoes degeneration rather than retraction during metamorphosis. Strikingly, the pruning process of the motor axon bundle is straightforward to investigate via live imaging and it occurs approximately at 22 h after pupal formation (APF), when axon bundles are completely cleared. Consistently, the classical axon pruning regulators in the Drosophila MB γ neuron, including TGF-β signaling, ecdysone signaling, JNK signaling, and the ubiquitin-proteasome system are also involved in governing motor axon pruning. Finally, our findings establish an unprecedented axon pruning mode that will serve to systematically screen and identify undiscovered axon pruning regulators. This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Wanyue Xu
- School of Life Science and Technology, the Key Laboratory of Developmental Genes and Human Disease, Southeast University, 2 Sipailou Road, Nanjing 210096, China
| | - Weiyu Kong
- School of Life Science and Technology, the Key Laboratory of Developmental Genes and Human Disease, Southeast University, 2 Sipailou Road, Nanjing 210096, China
| | - Ziyang Gao
- School of Life Science and Technology, the Key Laboratory of Developmental Genes and Human Disease, Southeast University, 2 Sipailou Road, Nanjing 210096, China
| | - Erqian Huang
- School of Life Science and Technology, the Key Laboratory of Developmental Genes and Human Disease, Southeast University, 2 Sipailou Road, Nanjing 210096, China
| | - Wei Xie
- School of Life Science and Technology, the Key Laboratory of Developmental Genes and Human Disease, Southeast University, 2 Sipailou Road, Nanjing 210096, China
| | - Su Wang
- School of Life Science and Technology, the Key Laboratory of Developmental Genes and Human Disease, Southeast University, 2 Sipailou Road, Nanjing 210096, China,Authors for correspondence (; )
| | - Menglong Rui
- School of Life Science and Technology, the Key Laboratory of Developmental Genes and Human Disease, Southeast University, 2 Sipailou Road, Nanjing 210096, China,Authors for correspondence (; )
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9
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Singh A, Yeates C, Deshpande P, Kango-Singh M. Signaling interactions among neurons impact cell fitness and death in Alzheimer’s disease. Neural Regen Res 2023; 18:784-789. [DOI: 10.4103/1673-5374.354516] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
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10
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Fasciclin 2 engages EGFR in an auto-stimulatory loop to promote imaginal disc cell proliferation in Drosophila. PLoS Genet 2022; 18:e1010224. [PMID: 35666718 PMCID: PMC9203005 DOI: 10.1371/journal.pgen.1010224] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Revised: 06/16/2022] [Accepted: 04/28/2022] [Indexed: 12/04/2022] Open
Abstract
How cell to cell interactions control local tissue growth to attain a species-specific organ size is a central question in developmental biology. The Drosophila Neural Cell Adhesion Molecule, Fasciclin 2, is expressed during the development of neural and epithelial organs. Fasciclin 2 is a homophilic-interaction protein that shows moderate levels of expression in the proliferating epithelia and high levels in the differentiating non-proliferative cells of imaginal discs. Genetic interactions and mosaic analyses reveal a cell autonomous requirement of Fasciclin 2 to promote cell proliferation in imaginal discs. This function is mediated by the EGFR, and indirectly involves the JNK and Hippo signaling pathways. We further show that Fasciclin 2 physically interacts with EGFR and that, in turn, EGFR activity promotes the cell autonomous expression of Fasciclin 2 during imaginal disc growth. We propose that this auto-stimulatory loop between EGFR and Fasciclin 2 is at the core of a cell to cell interaction mechanism that controls the amount of intercalary growth in imaginal discs. A key problem in developmental biology is how species-specific organ size is determined. Control of organ growth occurs at different levels of organization, from the systemic to the cell to cell interaction level. During nervous system development cell contact interactions regulate axon growth. Here, we show that one of the cell adhesion molecules involved in controlling axon growth, the Drosophila NCAM ortholog Fasciclin 2, also controls epithelial organ growth and size. Fasciclin 2 is expressed in highly dynamic but moderate levels during cell proliferation in imaginal discs (precursor epithelial organs of the adult epidermis), and at much higher level in pre-differentiating and differentiating cells in imaginal discs. During imaginal disc growth cell interactions mediated by Fasciclin 2 promote Epidermal Growth Factor Receptor function and cell proliferation. In turn, Epidermal Growth Factor Receptor activity promotes Fasciclin 2 expression, creating a cell autonomous auto-stimulatory loop that maintains cell proliferation. This function of Fasciclin 2 is reciprocal to its reported function in pre-differentiating and differentiating cells in imaginal discs, where it acts as an Epidermal Growth Factor Receptor repressor. Our study suggests that the amount of Fasciclin 2 may determine a threshold to grow or stop growing during epithelial organ development.
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11
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Meltzer H, Schuldiner O. Spatiotemporal Control of Neuronal Remodeling by Cell Adhesion Molecules: Insights From Drosophila. Front Neurosci 2022; 16:897706. [PMID: 35645712 PMCID: PMC9135462 DOI: 10.3389/fnins.2022.897706] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Accepted: 04/22/2022] [Indexed: 01/26/2023] Open
Abstract
Developmental neuronal remodeling is required for shaping the precise connectivity of the mature nervous system. Remodeling involves pruning of exuberant neural connections, often followed by regrowth of adult-specific ones, as a strategy to refine neural circuits. Errors in remodeling are associated with neurodevelopmental disorders such as schizophrenia and autism. Despite its fundamental nature, our understanding of the mechanisms governing neuronal remodeling is far from complete. Specifically, how precise spatiotemporal control of remodeling and rewiring is achieved is largely unknown. In recent years, cell adhesion molecules (CAMs), and other cell surface and secreted proteins of various families, have been implicated in processes of neurite pruning and wiring specificity during circuit reassembly. Here, we review some of the known as well as speculated roles of CAMs in these processes, highlighting recent advances in uncovering spatiotemporal aspects of regulation. Our focus is on the fruit fly Drosophila, which is emerging as a powerful model in the field, due to the extensive, well-characterized and stereotypic remodeling events occurring throughout its nervous system during metamorphosis, combined with the wide and constantly growing toolkit to identify CAM binding and resulting cellular interactions in vivo. We believe that its many advantages pose Drosophila as a leading candidate for future breakthroughs in the field of neuronal remodeling in general, and spatiotemporal control by CAMs specifically.
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Affiliation(s)
- Hagar Meltzer
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot, Israel
- Department of Molecular Neuroscience, Weizmann Institute of Science, Rehovot, Israel
- *Correspondence: Hagar Meltzer,
| | - Oren Schuldiner
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot, Israel
- Department of Molecular Neuroscience, Weizmann Institute of Science, Rehovot, Israel
- Oren Schuldiner,
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12
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Bornstein B, Meltzer H, Adler R, Alyagor I, Berkun V, Cummings G, Reh F, Keren‐Shaul H, David E, Riemensperger T, Schuldiner O. Transneuronal Dpr12/DIP-δ interactions facilitate compartmentalized dopaminergic innervation of Drosophila mushroom body axons. EMBO J 2021; 40:e105763. [PMID: 33847376 PMCID: PMC8204868 DOI: 10.15252/embj.2020105763] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Revised: 02/11/2021] [Accepted: 02/19/2021] [Indexed: 12/31/2022] Open
Abstract
The mechanisms controlling wiring of neuronal networks are not completely understood. The stereotypic architecture of the Drosophila mushroom body (MB) offers a unique system to study circuit assembly. The adult medial MB γ-lobe is comprised of a long bundle of axons that wire with specific modulatory and output neurons in a tiled manner, defining five distinct zones. We found that the immunoglobulin superfamily protein Dpr12 is cell-autonomously required in γ-neurons for their developmental regrowth into the distal γ4/5 zones, where both Dpr12 and its interacting protein, DIP-δ, are enriched. DIP-δ functions in a subset of dopaminergic neurons that wire with γ-neurons within the γ4/5 zone. During metamorphosis, these dopaminergic projections arrive to the γ4/5 zone prior to γ-axons, suggesting that γ-axons extend through a prepatterned region. Thus, Dpr12/DIP-δ transneuronal interaction is required for γ4/5 zone formation. Our study sheds light onto molecular and cellular mechanisms underlying circuit formation within subcellular resolution.
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Affiliation(s)
- Bavat Bornstein
- Department of Molecular Cell BiologyWeizmann Institute of ScienceRehovotIsrael
| | - Hagar Meltzer
- Department of Molecular Cell BiologyWeizmann Institute of ScienceRehovotIsrael
| | - Ruth Adler
- Department of Molecular Cell BiologyWeizmann Institute of ScienceRehovotIsrael
| | - Idan Alyagor
- Department of Molecular Cell BiologyWeizmann Institute of ScienceRehovotIsrael
| | - Victoria Berkun
- Department of Molecular Cell BiologyWeizmann Institute of ScienceRehovotIsrael
| | - Gideon Cummings
- Department of Molecular Cell BiologyWeizmann Institute of ScienceRehovotIsrael
| | - Fabienne Reh
- Institute of ZoologyUniversity of CologneKölnGermany
| | - Hadas Keren‐Shaul
- Department of ImmunologyWeizmann Institute of ScienceRehovotIsrael
- Life Science Core FacilityWeizmann Institute of ScienceRehovotIsrael
| | - Eyal David
- Department of ImmunologyWeizmann Institute of ScienceRehovotIsrael
| | | | - Oren Schuldiner
- Department of Molecular Cell BiologyWeizmann Institute of ScienceRehovotIsrael
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13
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Furusawa K, Emoto K. Spatiotemporal regulation of developmental neurite pruning: Molecular and cellular insights from Drosophila models. Neurosci Res 2020; 167:54-63. [PMID: 33309868 DOI: 10.1016/j.neures.2020.11.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Revised: 11/10/2020] [Accepted: 11/10/2020] [Indexed: 02/02/2023]
Abstract
Developmental neurite pruning is a process by which neurons selectively eliminate unnecessary processes of axons and/or dendrites without cell death, which shapes the mature wiring of nervous systems. In this sense, developmental neurite pruning requires spatiotemporally precise control of local degradation of cellular components including cytoskeletons and membranes. The Drosophila nervous system undergoes large-scale remodeling, including axon/dendrite pruning, during metamorphosis. In addition to this unique phenomenon in the nervous system, powerful genetic tools make the Drosophila nervous system a sophisticated model to investigate spatiotemporal regulation of neural remodeling. This article reviews recent advances to our understanding of the molecular and cellular mechanisms of developmental axon/dendrite pruning, mainly focusing on studies in Drosophila sensory neurons and mushroom body neurons.
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Affiliation(s)
- Kotaro Furusawa
- Department of Biological Sciences, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
| | - Kazuo Emoto
- Department of Biological Sciences, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan; International Research Center for Neurointelligence (WPI-IRCN), The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
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14
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Rui M, Bu S, Chew LY, Wang Q, Yu F. The membrane protein Raw regulates dendrite pruning via the secretory pathway. Development 2020; 147:dev.191155. [PMID: 32928906 DOI: 10.1242/dev.191155] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Accepted: 09/08/2020] [Indexed: 10/23/2022]
Abstract
Neuronal pruning is essential for proper wiring of the nervous systems in invertebrates and vertebrates. Drosophila ddaC sensory neurons selectively prune their larval dendrites to sculpt the nervous system during early metamorphosis. However, the molecular mechanisms underlying ddaC dendrite pruning remain elusive. Here, we identify an important and cell-autonomous role of the membrane protein Raw in dendrite pruning of ddaC neurons. Raw appears to regulate dendrite pruning via a novel mechanism, which is independent of JNK signaling. Importantly, we show that Raw promotes endocytosis and downregulation of the conserved L1-type cell-adhesion molecule Neuroglian (Nrg) prior to dendrite pruning. Moreover, Raw is required to modulate the secretory pathway by regulating the integrity of secretory organelles and efficient protein secretion. Mechanistically, Raw facilitates Nrg downregulation and dendrite pruning in part through regulation of the secretory pathway. Thus, this study reveals a JNK-independent role of Raw in regulating the secretory pathway and thereby promoting dendrite pruning.
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Affiliation(s)
- Menglong Rui
- Temasek Life Sciences Laboratory, 1 Research Link, National University of Singapore, Singapore 117604
| | - Shufeng Bu
- Temasek Life Sciences Laboratory, 1 Research Link, National University of Singapore, Singapore 117604.,Department of Biological Sciences, National University of Singapore, Singapore 117543
| | - Liang Yuh Chew
- Temasek Life Sciences Laboratory, 1 Research Link, National University of Singapore, Singapore 117604.,Department of Biological Sciences, National University of Singapore, Singapore 117543
| | - Qiwei Wang
- Temasek Life Sciences Laboratory, 1 Research Link, National University of Singapore, Singapore 117604.,Department of Biological Sciences, National University of Singapore, Singapore 117543
| | - Fengwei Yu
- Temasek Life Sciences Laboratory, 1 Research Link, National University of Singapore, Singapore 117604 .,Department of Biological Sciences, National University of Singapore, Singapore 117543.,NUS Graduate School for Integrative Sciences and Engineering, Centre for Life Sciences, Singapore 117456
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15
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With a little help from my friends: how intercellular communication shapes neuronal remodeling. Curr Opin Neurobiol 2020; 63:23-30. [PMID: 32092689 DOI: 10.1016/j.conb.2020.01.018] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Accepted: 01/28/2020] [Indexed: 11/22/2022]
Abstract
Developmental neuronal remodeling shapes the mature connectivity of the nervous system in both vertebrates and invertebrates. Remodeling often combines degenerative and regenerative events, and defects in its normal progression have been linked to neurological disorders. Here we review recent progress that highlights the roles of cell-cell interactions during remodeling. We propose that these are fundamental to elucidating how spatiotemporal control of remodeling and coordinated circuit remodeling are achieved. We cover examples spanning various neuronal circuits in vertebrates and invertebrates and involving interactions between neurons and different cell types.
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16
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Hao Y, Waller TJ, Nye DM, Li J, Zhang Y, Hume RI, Rolls MM, Collins CA. Degeneration of Injured Axons and Dendrites Requires Restraint of a Protective JNK Signaling Pathway by the Transmembrane Protein Raw. J Neurosci 2019; 39:8457-8470. [PMID: 31492772 PMCID: PMC6807270 DOI: 10.1523/jneurosci.0016-19.2019] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2019] [Revised: 08/08/2019] [Accepted: 08/22/2019] [Indexed: 12/15/2022] Open
Abstract
The degeneration of injured axons involves a self-destruction pathway whose components and mechanism are not fully understood. Here, we report a new regulator of axonal resilience. The transmembrane protein Raw is cell autonomously required for the degeneration of injured axons, dendrites, and synapses in Drosophila melanogaster In both male and female raw hypomorphic mutant or knock-down larvae, the degeneration of injured axons, dendrites, and synapses from motoneurons and sensory neurons is strongly inhibited. This protection is insensitive to reduction in the levels of the NAD+ synthesis enzyme Nmnat (nicotinamide mononucleotide adenylyl transferase), but requires the c-Jun N-terminal kinase (JNK) mitogen-activated protein (MAP) kinase and the transcription factors Fos and Jun (AP-1). Although these factors were previously known to function in axonal injury signaling and regeneration, Raw's function can be genetically separated from other axonal injury responses: Raw does not modulate JNK-dependent axonal injury signaling and regenerative responses, but instead restrains a protective pathway that inhibits the degeneration of axons, dendrites, and synapses. Although protection in raw mutants requires JNK, Fos, and Jun, JNK also promotes axonal degeneration. These findings suggest the existence of multiple independent pathways that share modulation by JNK, Fos, and Jun that influence how axons respond to stress and injury.SIGNIFICANCE STATEMENT Axonal degeneration is a major feature of neuropathies and nerve injuries and occurs via a cell autonomous self-destruction pathway whose mechanism is poorly understood. This study reports the identification of a new regulator of axonal degeneration: the transmembrane protein Raw. Raw regulates a cell autonomous nuclear signaling pathway whose yet unknown downstream effectors protect injured axons, dendrites, and synapses from degenerating. These findings imply that the susceptibility of axons to degeneration is strongly regulated in neurons. Future understanding of the cellular pathway regulated by Raw, which engages the c-Jun N-terminal kinase (JNK) mitogen-activated protein (MAP) kinase and Fos and Jun transcription factors, may suggest new strategies to increase the resiliency of axons in debilitating neuropathies.
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Affiliation(s)
- Yan Hao
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, Michigan 48109-1085
| | - Thomas J Waller
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, Michigan 48109-1085
| | - Derek M Nye
- Huck Institutes of the Life Sciences, and Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802, and
| | - Jiaxing Li
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, Michigan 48109-1085
| | - Yanxiao Zhang
- Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, Michigan 48109-2218
| | - Richard I Hume
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, Michigan 48109-1085
| | - Melissa M Rolls
- Huck Institutes of the Life Sciences, and Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802, and
| | - Catherine A Collins
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, Michigan 48109-1085,
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17
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Wang ZH, Liu Y, Chaitankar V, Pirooznia M, Xu H. Electron transport chain biogenesis activated by a JNK-insulin-Myc relay primes mitochondrial inheritance in Drosophila. eLife 2019; 8:49309. [PMID: 31612862 PMCID: PMC6809605 DOI: 10.7554/elife.49309] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Accepted: 10/13/2019] [Indexed: 12/25/2022] Open
Abstract
Oogenesis features an enormous increase in mitochondrial mass and mtDNA copy number, which are required to furnish mature eggs with an adequate supply of mitochondria and to curb the transmission of deleterious mtDNA variants. Quiescent in dividing germ cells, mtDNA replication initiates upon oocyte determination in the Drosophila ovary, which necessitates active mitochondrial respiration. However, the underlying mechanism for this dynamic regulation remains unclear. Here, we show that an feedforward insulin-Myc loop promotes mitochondrial respiration and biogenesis by boosting the expression of electron transport chain subunits and of factors essential for mtDNA replication and expression, and for the import of mitochondrial proteins. We further reveal that transient activation of JNK enhances the expression of the insulin receptor and initiates the insulin-Myc signaling loop. This signaling relay promotes mitochondrial biogenesis in the ovary, and thereby plays a role in limiting the transmission of deleterious mtDNA mutations. Our study demonstrates cellular mechanisms that couple mitochondrial biogenesis and inheritance with oocyte development.
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Affiliation(s)
- Zong-Heng Wang
- National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, United States
| | - Yi Liu
- National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, United States
| | - Vijender Chaitankar
- National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, United States
| | - Mehdi Pirooznia
- National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, United States
| | - Hong Xu
- National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, United States
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18
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The Drosophila Chromodomain Protein Kismet Activates Steroid Hormone Receptor Transcription to Govern Axon Pruning and Memory In Vivo. iScience 2019; 16:79-93. [PMID: 31153043 PMCID: PMC6543131 DOI: 10.1016/j.isci.2019.05.021] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Revised: 02/08/2019] [Accepted: 05/13/2019] [Indexed: 11/23/2022] Open
Abstract
Axon pruning is critical for sculpting precise neural circuits. Although axon pruning has been described in the literature for decades, relatively little is known about the molecular and cellular mechanisms that govern axon pruning in vivo. Here, we show that the epigenetic reader Kismet (Kis) is required for developmental axon pruning in Drosophila mushroom bodies. Kis binds to cis-regulatory elements of the steroid hormone receptor ecdysone receptor (ecr) gene and is necessary for activating expression of EcR-B1. Kis promotes the active H3K36 di- and tri-methylation and H4K16 acetylation histone marks at the ecr locus. We show that transgenic EcR-B1 can rescue axon pruning and memory defects associated with loss of Kis and that the histone deacetylase inhibitor SAHA also rescues these phenotypes. EcR protein abundance is the cell-autonomous, rate-limiting step required to initiate axon pruning in Drosophila, and our data suggest this step is under the epigenetic control of Kis.
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19
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Meltzer H, Marom E, Alyagor I, Mayseless O, Berkun V, Segal-Gilboa N, Unger T, Luginbuhl D, Schuldiner O. Tissue-specific (ts)CRISPR as an efficient strategy for in vivo screening in Drosophila. Nat Commun 2019; 10:2113. [PMID: 31068592 PMCID: PMC6506539 DOI: 10.1038/s41467-019-10140-0] [Citation(s) in RCA: 59] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Accepted: 04/17/2019] [Indexed: 12/22/2022] Open
Abstract
Gene editing by CRISPR/Cas9 is commonly used to generate germline mutations or perform in vitro screens, but applicability for in vivo screening has so far been limited. Recently, it was shown that in Drosophila, Cas9 expression could be limited to a desired group of cells, allowing tissue-specific mutagenesis. Here, we thoroughly characterize tissue-specific (ts)CRISPR within the complex neuronal system of the Drosophila mushroom body. We report the generation of a library of gRNA-expressing plasmids and fly lines using optimized tools, which provides a valuable resource to the fly community. We demonstrate the application of our library in a large-scale in vivo screen, which reveals insights into developmental neuronal remodeling.
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Affiliation(s)
- Hagar Meltzer
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot, Israel
| | - Efrat Marom
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot, Israel
| | - Idan Alyagor
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot, Israel
| | - Oded Mayseless
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot, Israel
| | - Victoria Berkun
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot, Israel
| | - Netta Segal-Gilboa
- Structural Proteomics Unit, Weizmann Institute of Science, Rehovot, Israel
| | - Tamar Unger
- Structural Proteomics Unit, Weizmann Institute of Science, Rehovot, Israel
| | - David Luginbuhl
- Howard Hughes Medical Institute, Department of Biology, Stanford University, Stanford, USA
| | - Oren Schuldiner
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot, Israel.
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20
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Kroeze Y, Oti M, van Beusekom E, Cooijmans RHM, van Bokhoven H, Kolk SM, Homberg JR, Zhou H. Transcriptome Analysis Identifies Multifaceted Regulatory Mechanisms Dictating a Genetic Switch from Neuronal Network Establishment to Maintenance During Postnatal Prefrontal Cortex Development. Cereb Cortex 2019; 28:833-851. [PMID: 28108491 DOI: 10.1093/cercor/bhw407] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Indexed: 12/20/2022] Open
Abstract
The prefrontal cortex (PFC) is one of the latest brain regions to mature, which allows the acquisition of complex cognitive abilities through experience. To unravel the underlying gene expression changes during postnatal development, we performed RNA-sequencing (RNA-seq) in the rat medial PFC (mPFC) at five developmental time points from infancy to adulthood, and analyzed the differential expression of protein-coding genes, long intergenic noncoding RNAs (lincRNAs), and alternative exons. We showed that most expression changes occur in infancy, and that the number of differentially expressed genes reduces toward adulthood. We observed 137 differentially expressed lincRNAs and 796 genes showing alternative exon usage during postnatal development. Importantly, we detected a genetic switch from neuronal network establishment in infancy to maintenance of neural networks in adulthood based on gene expression dynamics, involving changes in protein-coding and lincRNA gene expression as well as alternative exon usage. Our gene expression datasets provide insights into the multifaceted transcriptional regulation of the developing PFC. They can be used to study the basic developmental processes of the mPFC and to understand the mechanisms of neurodevelopmental and neuropsychiatric disorders. Our study provides an important contribution to the ongoing efforts to complete the "brain map", and to the understanding of PFC development.
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Affiliation(s)
- Yvet Kroeze
- Department of Cognitive Neuroscience, Centre for Neuroscience, Donders Institute for Brain, Cognition, and Behaviour, Radboud University Medical Centre, 6525 EZ Nijmegen, The Netherlands.,Department of Human Genetics, Centre for Neuroscience, Donders Institute for Brain, Cognition, and Behaviour, Radboud University Medical Centre, 6525 GA Nijmegen, The Netherlands
| | - Martin Oti
- Department of Molecular Developmental Biology, Faculty of Science, Radboud Institute for Molecular Life Sciences, Radboud University, 6525 GA Nijmegen, The Netherlands.,Carlos Chagas Filho Biophysics Institute (IBCCF), Federal University of Rio de Janeiro (UFRJ), 21941-902 Rio de Janeiro, Brazil
| | - Ellen van Beusekom
- Department of Human Genetics, Centre for Neuroscience, Donders Institute for Brain, Cognition, and Behaviour, Radboud University Medical Centre, 6525 GA Nijmegen, The Netherlands
| | - Roel H M Cooijmans
- Department of Molecular Developmental Biology, Faculty of Science, Radboud Institute for Molecular Life Sciences, Radboud University, 6525 GA Nijmegen, The Netherlands
| | - Hans van Bokhoven
- Department of Human Genetics, Centre for Neuroscience, Donders Institute for Brain, Cognition, and Behaviour, Radboud University Medical Centre, 6525 GA Nijmegen, The Netherlands
| | - Sharon M Kolk
- Department of Molecular Animal Physiology, Centre for Neuroscience, Donders Institute for Brain, Cognition, and Behaviour, Radboud University, 6525 GA Nijmegen, The Netherlands
| | - Judith R Homberg
- Department of Cognitive Neuroscience, Centre for Neuroscience, Donders Institute for Brain, Cognition, and Behaviour, Radboud University Medical Centre, 6525 EZ Nijmegen, The Netherlands
| | - Huiqing Zhou
- Department of Human Genetics, Centre for Neuroscience, Donders Institute for Brain, Cognition, and Behaviour, Radboud University Medical Centre, 6525 GA Nijmegen, The Netherlands.,Department of Molecular Developmental Biology, Faculty of Science, Radboud Institute for Molecular Life Sciences, Radboud University, 6525 GA Nijmegen, The Netherlands
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21
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Zhu S, Chen R, Soba P, Jan YN. JNK signaling coordinates with ecdysone signaling to promote pruning of Drosophila sensory neuron dendrites. Development 2019; 146:dev.163592. [PMID: 30936183 DOI: 10.1242/dev.163592] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2018] [Accepted: 03/25/2019] [Indexed: 12/15/2022]
Abstract
Developmental pruning of axons and dendrites is crucial for the formation of precise neuronal connections, but the mechanisms underlying developmental pruning are not fully understood. Here, we have investigated the function of JNK signaling in dendrite pruning using Drosophila class IV dendritic arborization (c4da) neurons as a model. We find that loss of JNK or its canonical downstream effectors Jun or Fos led to dendrite-pruning defects in c4da neurons. Interestingly, our data show that JNK activity in c4da neurons remains constant from larval to pupal stages but the expression of Fos is specifically activated by ecdysone receptor B1 (EcRB1) at early pupal stages, suggesting that ecdysone signaling provides temporal control of the regulation of dendrite pruning by JNK signaling. Thus, our work not only identifies a novel pathway involved in dendrite pruning and a new downstream target of EcRB1 in c4da neurons, but also reveals that JNK and Ecdysone signaling coordinate to promote dendrite pruning.
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Affiliation(s)
- Sijun Zhu
- Department of Neuroscience and Physiology, State University of New York Upstate Medical University, Syracuse, NY 13210, USA .,Department of Physiology, Howard Hughes Medical Institute, University of California San Francisco, San Francisco, CA 20251, USA
| | - Rui Chen
- Department of Neuroscience and Physiology, State University of New York Upstate Medical University, Syracuse, NY 13210, USA
| | - Peter Soba
- Department of Physiology, Howard Hughes Medical Institute, University of California San Francisco, San Francisco, CA 20251, USA.,Center for Molecular Neurobiology (ZMNH), University Medical Center Hamburg-Eppendorf, University of Hamburg, Hamburg, Germany
| | - Yuh-Nung Jan
- Department of Physiology, Howard Hughes Medical Institute, University of California San Francisco, San Francisco, CA 20251, USA
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22
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Chubak MC, Nixon KCJ, Stone MH, Raun N, Rice SL, Sarikahya M, Jones SG, Lyons TA, Jakub TE, Mainland RLM, Knip MJ, Edwards TN, Kramer JM. Individual components of the SWI/SNF chromatin remodelling complex have distinct roles in memory neurons of the Drosophila mushroom body. Dis Model Mech 2019; 12:12/3/dmm037325. [PMID: 30923190 PMCID: PMC6451433 DOI: 10.1242/dmm.037325] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Accepted: 02/23/2019] [Indexed: 12/13/2022] Open
Abstract
Technology has led to rapid progress in the identification of genes involved in neurodevelopmental disorders such as intellectual disability (ID), but our functional understanding of the causative genes is lagging. Here, we show that the SWI/SNF chromatin remodelling complex is one of the most over-represented cellular components disrupted in ID. We investigated the role of individual subunits of this large protein complex using targeted RNA interference in post-mitotic memory-forming neurons of the Drosophila mushroom body (MB). Knockdown flies were tested for defects in MB morphology, short-term memory and long-term memory. Using this approach, we identified distinct roles for individual subunits of the Drosophila SWI/SNF complex. Bap60, Snr1 and E(y)3 are required for pruning of the MBγ neurons during pupal morphogenesis, while Brm and Osa are required for survival of MBγ axons during ageing. We used the courtship conditioning assay to test the effect of MB-specific SWI/SNF knockdown on short- and long-term memory. Several subunits, including Brm, Bap60, Snr1 and E(y)3, were required in the MB for both short- and long-term memory. In contrast, Osa knockdown only reduced long-term memory. Our results suggest that individual components of the SWI/SNF complex have different roles in the regulation of structural plasticity, survival and functionality of post-mitotic MB neurons. This study highlights the many possible processes that might be disrupted in SWI/SNF-related ID disorders. Our broad phenotypic characterization provides a starting point for understanding SWI/SNF-mediated gene regulatory mechanisms that are important for development and function of post-mitotic neurons. Summary: The SWI/SNF chromatin remodelling complex is the most over-represented protein complex in the intellectual disability. Different components of this complex have distinct roles in development and function of memory-forming neurons in the Drosophila mushroom body.
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Affiliation(s)
- Melissa C Chubak
- Department of Biology, Faculty of Science, Western University, London, ON N6A 5B7, Canada
| | - Kevin C J Nixon
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, Western University, London, ON N6A 5C1, Canada
| | - Max H Stone
- Department of Biology, Faculty of Science, Western University, London, ON N6A 5B7, Canada.,Division of Genetics and Development, Children's Health Research Institute, London, ON N6C 2V5, Canada
| | - Nicholas Raun
- Department of Biology, Faculty of Science, Western University, London, ON N6A 5B7, Canada.,Division of Genetics and Development, Children's Health Research Institute, London, ON N6C 2V5, Canada
| | - Shelby L Rice
- Department of Biology, Faculty of Science, Western University, London, ON N6A 5B7, Canada
| | - Mohammed Sarikahya
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, Western University, London, ON N6A 5C1, Canada
| | - Spencer G Jones
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, Western University, London, ON N6A 5C1, Canada
| | - Taylor A Lyons
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, Western University, London, ON N6A 5C1, Canada
| | - Taryn E Jakub
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, Western University, London, ON N6A 5C1, Canada
| | - Roslyn L M Mainland
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, Western University, London, ON N6A 5C1, Canada
| | - Maria J Knip
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, Western University, London, ON N6A 5C1, Canada
| | - Tara N Edwards
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, Western University, London, ON N6A 5C1, Canada
| | - Jamie M Kramer
- Department of Biology, Faculty of Science, Western University, London, ON N6A 5B7, Canada .,Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, Western University, London, ON N6A 5C1, Canada.,Division of Genetics and Development, Children's Health Research Institute, London, ON N6C 2V5, Canada
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Sphingolipid-dependent Dscam sorting regulates axon segregation. Nat Commun 2019; 10:813. [PMID: 30778062 PMCID: PMC6379420 DOI: 10.1038/s41467-019-08765-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2016] [Accepted: 01/17/2019] [Indexed: 12/22/2022] Open
Abstract
Neurons are highly polarized cells with distinct protein compositions in axonal and dendritic compartments. Cellular mechanisms controlling polarized protein sorting have been described for mature nervous system but little is known about the segregation in newly differentiated neurons. In a forward genetic screen for regulators of Drosophila brain circuit development, we identified mutations in SPT, an evolutionary conserved enzyme in sphingolipid biosynthesis. Here we show that reduced levels of sphingolipids in SPT mutants cause axonal morphology defects similar to loss of cell recognition molecule Dscam. Loss- and gain-of-function studies show that neuronal sphingolipids are critical to prevent aggregation of axonal and dendritic Dscam isoforms, thereby ensuring precise Dscam localization to support axon branch segregation. Furthermore, SPT mutations causing neurodegenerative HSAN-I disorder in humans also result in formation of stable Dscam aggregates and axonal branch phenotypes in Drosophila neurons, indicating a causal link between developmental protein sorting defects and neuronal dysfunction. Little is known about the initial segregation of axonal and dendritic proteins during the differentiation of newly generated neurons. Here authors use a forward genetic screen to identify the role of sphingolipids in regulating the sub-cellular distribution of Dscam for neuronal patterning in Drosophila Mushroom Bodies
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Sar Shalom H, Goldner R, Golan-Vaishenker Y, Yaron A. Balance between BDNF and Semaphorins gates the innervation of the mammary gland. eLife 2019; 8:41162. [PMID: 30628891 PMCID: PMC6328272 DOI: 10.7554/elife.41162] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Accepted: 12/07/2018] [Indexed: 01/01/2023] Open
Abstract
The innervation of the mammary gland is controlled by brain-derived neurotrophic factor (BDNF), and sexually dimorphic sequestering of BDNF by the truncated form of TrkB (TrkB.T1) directs male-specific axonal pruning in mice. It is unknown whether other cues modulate these processes. We detected specific, non-dimorphic, expression of Semaphorin family members in the mouse mammary gland, which signal through PlexinA4. PlexinA4 deletion in both female and male embryos caused developmental hyperinnervation of the gland, which could be reduced by genetic co-reduction of BDNF. Moreover, in males, PlexinA4 ablation delayed axonal pruning, independently of the initial levels of innervation. In support of this, in vitro reduction of BDNF induced axonal hypersensitivity to PlexinA4 signaling. Overall, our study shows that precise sensory innervation of the mammary gland is regulated by the balance between trophic and repulsive signaling. Upon inhibition of trophic signaling, these repulsive factors may promote axonal pruning.
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Affiliation(s)
- Hadas Sar Shalom
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Ron Goldner
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
| | | | - Avraham Yaron
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
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25
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Developmental Coordination during Olfactory Circuit Remodeling in Drosophila. Neuron 2018; 99:1204-1215.e5. [PMID: 30146303 DOI: 10.1016/j.neuron.2018.07.050] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Revised: 06/03/2018] [Accepted: 07/27/2018] [Indexed: 02/03/2023]
Abstract
Developmental neuronal remodeling is crucial for proper wiring of the adult nervous system. While remodeling of individual neuronal populations has been studied, how neuronal circuits remodel-and whether remodeling of synaptic partners is coordinated-is unknown. We found that the Drosophila anterior paired lateral (APL) neuron undergoes stereotypic remodeling during metamorphosis in a similar time frame as the mushroom body (MB) ɣ-neurons, with whom it forms a functional circuit. By simultaneously manipulating both neuronal populations, we found that cell-autonomous inhibition of ɣ-neuron pruning resulted in the inhibition of APL pruning in a process that is mediated, at least in part, by Ca2+-Calmodulin and neuronal activity dependent interaction. Finally, ectopic unpruned MB ɣ axons display ectopic connections with the APL, as well as with other neurons, at the adult, suggesting that inhibiting remodeling of one neuronal type can affect the functional wiring of the entire micro-circuit.
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DISCO interacting protein 2 determines direction of axon projection under the regulation of c-Jun N-terminal kinase in the Drosophila mushroom body. Biochem Biophys Res Commun 2017; 487:116-121. [DOI: 10.1016/j.bbrc.2017.04.028] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Accepted: 04/07/2017] [Indexed: 11/21/2022]
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27
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dMyc is required in retinal progenitors to prevent JNK-mediated retinal glial activation. PLoS Genet 2017; 13:e1006647. [PMID: 28267791 PMCID: PMC5360344 DOI: 10.1371/journal.pgen.1006647] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2016] [Revised: 03/21/2017] [Accepted: 02/21/2017] [Indexed: 11/25/2022] Open
Abstract
In the nervous system, glial cells provide crucial insulation and trophic support to neurons and are important for neuronal survival. In reaction to a wide variety of insults, glial cells respond with changes in cell morphology and metabolism to allow repair. Additionally, these cells can acquire migratory and proliferative potential. In particular, after axonal damage or pruning the clearance of axonal debris by glial cells is key for a healthy nervous system. Thus, bidirectional neuron-glial interactions are crucial in development, but little is known about the cellular sensors and signalling pathways involved. In here, we show that decreased cellular fitness in retinal progenitors caused by reduced Drosophila Myc expression triggers non cell-autonomous activation of retinal glia proliferation and overmigration. Glia migration occurs beyond its normal limit near the boundary between differentiated photoreceptors and precursor cells, extending into the progenitor domain. This overmigration is stimulated by JNK activation (and the function of its target Mmp1), while proliferative responses are mediated by Dpp/TGF-β signalling activation. For a functional nervous system, neurons transmit information from cell to cell while glial cells provide crucial insulation and trophic support to neurons, which is important for neuronal survival. Glial cells are one of the most plastic cell types being able to adapt and respond to changing environmental stimuli. In this work we inhibit the function of the growth regulator dMyc in Drosophila retinal primordium, the eye imaginal discs. Glial cell numbers and migration pattern to the eye disc are tightly controlled but in dMyc-depleted retinas the glial cells overcome their normal barriers and overmigrate into the eye progenitors domain. We show evidence that this process is mediated by JNK activation in the presence of metalloproteinases. We discuss the biological role of overmigrating glia in tissue regeneration and/or confinement of the damaged area.
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Axon Termination, Pruning, and Synaptogenesis in the Giant Fiber System of Drosophila melanogaster Is Promoted by Highwire. Genetics 2017; 205:1229-1245. [PMID: 28100586 DOI: 10.1534/genetics.116.197343] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Accepted: 12/20/2016] [Indexed: 11/18/2022] Open
Abstract
The ubiquitin ligase Highwire has a conserved role in synapse formation. Here, we show that Highwire coordinates several facets of central synapse formation in the Drosophila melanogaster giant fiber system, including axon termination, axon pruning, and synaptic function. Despite the similarities to the fly neuromuscular junction, the role of Highwire and the underlying signaling pathways are distinct in the fly's giant fiber system. During development, branching of the giant fiber presynaptic terminal occurs and, normally, the transient branches are pruned away. However, in highwire mutants these ectopic branches persist, indicating that Highwire promotes axon pruning. highwire mutants also exhibit defects in synaptic function. Highwire promotes axon pruning and synaptic function cell-autonomously by attenuating a mitogen-activated protein kinase pathway including Wallenda, c-Jun N-terminal kinase/Basket, and the transcription factor Jun. We also show a novel role for Highwire in non-cell autonomous promotion of synaptic function from the midline glia. Highwire also regulates axon termination in the giant fibers, as highwire mutant axons exhibit severe overgrowth beyond the pruning defect. This excessive axon growth is increased by manipulating Fos expression in the cells surrounding the giant fiber terminal, suggesting that Fos regulates a trans-synaptic signal that promotes giant fiber axon growth.
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29
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Wang Y, Zhang H, Shi M, Liou YC, Lu L, Yu F. Sec71 functions as a GEF for the small GTPase Arf1 to govern dendrite pruning of Drosophila sensory neurons. Development 2017; 144:1851-1862. [DOI: 10.1242/dev.146175] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Accepted: 03/29/2017] [Indexed: 01/20/2023]
Abstract
Pruning, whereby neurons eliminate their exuberant neurites, is central for the maturation of the nervous system. In Drosophila, sensory neurons, ddaCs, selectively prune their larval dendrites without affecting their axons during metamorphosis. However, it is unknown whether the secretory pathway plays a role in dendrite pruning. Here, we show that the small GTPase Arf1, an important regulator of secretory pathway, is specifically required for dendrite pruning of ddaC/D/E sensory neurons but dispensable for apoptosis of ddaF neurons. Analyses of the GTP and GDP-locked forms of Arf1 indicate that the cycling of Arf1 between GDP-bound and GTP-bound forms is essential for dendrite pruning. We further identified Sec71 as a guanine nucleotide exchange factor for Arf1 that preferentially interacts with its GDP-bound form. Like Arf1, Sec71 is also important for dendrite pruning, but not apoptosis, of sensory neurons. Arf1 and Sec71 are interdependent for their localizations on Golgi. Finally, we show that Sec71/Arf1-mediated trafficking process is a prerequisite for Rab5-dependent endocytosis to facilitate endocytosis and degradation of the cell adhesion molecule Neuroglian (Nrg).
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Affiliation(s)
- Yan Wang
- Temasek Life Sciences Laboratory and Department of Biological Sciences, 1 Research Link, National University of Singapore, Singapore, 117604
- NUS Graduate School for Integrative Sciences and Engineering, Centre for Life Sciences, Singapore, 117456
| | - Heng Zhang
- Temasek Life Sciences Laboratory and Department of Biological Sciences, 1 Research Link, National University of Singapore, Singapore, 117604
| | - Meng Shi
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore, 637551
| | - Yih-Cherng Liou
- Temasek Life Sciences Laboratory and Department of Biological Sciences, 1 Research Link, National University of Singapore, Singapore, 117604
- NUS Graduate School for Integrative Sciences and Engineering, Centre for Life Sciences, Singapore, 117456
| | - Lei Lu
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore, 637551
| | - Fengwei Yu
- Temasek Life Sciences Laboratory and Department of Biological Sciences, 1 Research Link, National University of Singapore, Singapore, 117604
- NUS Graduate School for Integrative Sciences and Engineering, Centre for Life Sciences, Singapore, 117456
- Neuroscience and Behavioral Disorder Program, Duke-NUS Graduate Medical School Singapore, 8 College Road, Singapore, 169857
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30
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McFarlin BK, Gary MA. Flow cytometry what you see matters: Enhanced clinical detection using image-based flow cytometry. Methods 2016; 112:1-8. [PMID: 27620330 DOI: 10.1016/j.ymeth.2016.09.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2016] [Revised: 09/01/2016] [Accepted: 09/08/2016] [Indexed: 02/08/2023] Open
Abstract
Image-based flow cytometry combines the throughput of traditional flow cytometry with the ability to visually confirm findings and collect novel data that would not be possible otherwise. Since image-based flow cytometry borrows measurement parameters and analysis techniques from microscopy, it is possible to collect unique measures (i.e. nuclear translocation, co-localization, cellular synapse, cellular endocytosis, etc.) that would not be possible with traditional flow cytometry. The ability to collect unique outcomes has led many researchers to develop novel assays for the monitoring and detection of a variety of clinical conditions and diseases. In many cases, investigators have innovated and expanded classical assays to provide new insight regarding clinical conditions and chronic disease. Beyond human clinical applications, image-based flow cytometry has been used to monitor marine biology changes, nano-particles for solar cell production, and particle quality in pharmaceuticals. This review article summarizes work from the major scientists working in the field of image-based flow cytometry.
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Affiliation(s)
- Brian K McFarlin
- University of North Texas, Applied Physiology Laboratory, United States; University of North Texas, Department of Biological Sciences, United States.
| | - Melody A Gary
- University of North Texas, Applied Physiology Laboratory, United States
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31
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Terni B, López-Murcia FJ, Llobet A. Role of neuron-glia interactions in developmental synapse elimination. Brain Res Bull 2016; 129:74-81. [PMID: 27601093 DOI: 10.1016/j.brainresbull.2016.08.017] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2016] [Revised: 08/19/2016] [Accepted: 08/31/2016] [Indexed: 11/16/2022]
Abstract
During the embryonic development of the nervous system there is a massive formation of synapses. However, the exuberant connectivity present after birth must be pruned during postnatal growth to optimize the function of neuronal circuits. Whilst glial cells play a fundamental role in the formation of early synaptic contacts, their contribution to developmental modifications of established synapses is not well understood. The present review aims to highlight the various roles of glia in the developmental refinement of embryonic synaptic connectivity. We summarize recent evidences linking secretory abilities of glial cells to the disassembly of synaptic contacts that are complementary of a well-established phagocytic role. Considering a theoretical framework, it is discussed how release of glial molecules could be relevant to the developmental refinement of synaptic connectivity. Finally, we propose a three-stage model of synapse elimination in which neurons and glia are functionally associated to timely eliminate synapses.
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Affiliation(s)
- Beatrice Terni
- Laboratory of Neurobiology, Department of Pathology and Experimental Therapeutics, Institute of Neurosciences, University of Barcelona and Bellvitge Biomedical Research Institute (IDIBELL), 08907 L'Hospitalet de Llobregat, Barcelona, Spain
| | - Francisco José López-Murcia
- Laboratory of Neurobiology, Department of Pathology and Experimental Therapeutics, Institute of Neurosciences, University of Barcelona and Bellvitge Biomedical Research Institute (IDIBELL), 08907 L'Hospitalet de Llobregat, Barcelona, Spain
| | - Artur Llobet
- Laboratory of Neurobiology, Department of Pathology and Experimental Therapeutics, Institute of Neurosciences, University of Barcelona and Bellvitge Biomedical Research Institute (IDIBELL), 08907 L'Hospitalet de Llobregat, Barcelona, Spain.
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32
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Yaniv SP, Schuldiner O. A fly's view of neuronal remodeling. WILEY INTERDISCIPLINARY REVIEWS-DEVELOPMENTAL BIOLOGY 2016; 5:618-35. [PMID: 27351747 PMCID: PMC5086085 DOI: 10.1002/wdev.241] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/03/2016] [Revised: 04/10/2016] [Accepted: 04/18/2016] [Indexed: 11/17/2022]
Abstract
Developmental neuronal remodeling is a crucial step in sculpting the final and mature brain connectivity in both vertebrates and invertebrates. Remodeling includes degenerative events, such as neurite pruning, that may be followed by regeneration to form novel connections during normal development. Drosophila provides an excellent model to study both steps of remodeling since its nervous system undergoes massive and stereotypic remodeling during metamorphosis. Although pruning has been widely studied, our knowledge of the molecular and cellular mechanisms is far from complete. Our understanding of the processes underlying regrowth is even more fragmentary. In this review, we discuss recent progress by focusing on three groups of neurons that undergo stereotypic pruning and regrowth during metamorphosis, the mushroom body γ neurons, the dendritic arborization neurons and the crustacean cardioactive peptide peptidergic neurons. By comparing and contrasting the mechanisms involved in remodeling of these three neuronal types, we highlight the common themes and differences as well as raise key questions for future investigation in the field. WIREs Dev Biol 2016, 5:618–635. doi: 10.1002/wdev.241 For further resources related to this article, please visit the WIREs website
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Affiliation(s)
- Shiri P Yaniv
- Dept of Molecular Cell Biology, Weizmann Institute of Science, Rehovot, Israel
| | - Oren Schuldiner
- Dept of Molecular Cell Biology, Weizmann Institute of Science, Rehovot, Israel
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33
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Abstract
Immature neural circuits form excessive synaptic connections that are later refined through pruning of exuberant branches. In this issue, Bornstein et al. identify a role for JNK signaling in selective axon elimination through disassembly of cell adhesion complexes.
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Affiliation(s)
- Jonathan E Farley
- Department of Neurobiology/HHMI, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Marc R Freeman
- Department of Neurobiology/HHMI, University of Massachusetts Medical School, Worcester, MA 01605, USA.
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