1
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Sadria M, Layton A, Goyal S, Bader GD. Fatecode enables cell fate regulator prediction using classification-supervised autoencoder perturbation. CELL REPORTS METHODS 2024; 4:100819. [PMID: 38986613 PMCID: PMC11294839 DOI: 10.1016/j.crmeth.2024.100819] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Revised: 11/20/2023] [Accepted: 06/18/2024] [Indexed: 07/12/2024]
Abstract
Cell reprogramming, which guides the conversion between cell states, is a promising technology for tissue repair and regeneration, with the ultimate goal of accelerating recovery from diseases or injuries. To accomplish this, regulators must be identified and manipulated to control cell fate. We propose Fatecode, a computational method that predicts cell fate regulators based only on single-cell RNA sequencing (scRNA-seq) data. Fatecode learns a latent representation of the scRNA-seq data using a deep learning-based classification-supervised autoencoder and then performs in silico perturbation experiments on the latent representation to predict genes that, when perturbed, would alter the original cell type distribution to increase or decrease the population size of a cell type of interest. We assessed Fatecode's performance using simulations from a mechanistic gene-regulatory network model and scRNA-seq data mapping blood and brain development of different organisms. Our results suggest that Fatecode can detect known cell fate regulators from single-cell transcriptomics datasets.
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Affiliation(s)
- Mehrshad Sadria
- Department of Applied Mathematics, University of Waterloo, Waterloo, ON, Canada.
| | - Anita Layton
- Department of Applied Mathematics, University of Waterloo, Waterloo, ON, Canada; Cheriton School of Computer Science, University of Waterloo, Waterloo, ON, Canada; Department of Biology, University of Waterloo, Waterloo, ON, Canada; School of Pharmacy, University of Waterloo, Waterloo, ON, Canada
| | - Sidhartha Goyal
- Department of Physics, University of Toronto, Toronto, ON, Canada
| | - Gary D Bader
- Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada; The Donnelly Centre, University of Toronto, Toronto, ON, Canada; Department of Computer Science, University of Toronto, Toronto, ON, Canada; The Lunenfeld-Tanenbaum Research Institute, Sinai Health System, Toronto, ON, Canada; Princess Margaret Cancer Centre, University Health Network, Toronto, ON, Canada; Canadian Institute for Advanced Research (CIFAR), Toronto, ON, Canada
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2
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Morano NC, Lopez DH, Meltzer H, Sergeeva AP, Katsamba PS, Rostam KD, Gupta HP, Becker JE, Bornstein B, Cosmanescu F, Schuldiner O, Honig B, Mann RS, Shapiro L. Cis inhibition of co-expressed DIPs and Dprs shapes neural development. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.04.583391. [PMID: 38895375 PMCID: PMC11185508 DOI: 10.1101/2024.03.04.583391] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/21/2024]
Abstract
In Drosophila , two interacting adhesion protein families, Dprs and DIPs, coordinate the assembly of neural networks. While intercellular DIP/Dpr interactions have been well characterized, DIPs and Dprs are often co-expressed within the same cells, raising the question as to whether they also interact in cis . We show, in cultured cells and in vivo, that DIP-α and DIP-δ can interact in cis with their ligands, Dpr6/10 and Dpr12, respectively. When co-expressed in cis with their cognate partners, these Dprs regulate the extent of trans binding, presumably through competitive cis interactions. We demonstrate the neurodevelopmental effects of cis inhibition in fly motor neurons and in the mushroom body. We further show that a long disordered region of DIP-α at the C-terminus is required for cis but not trans interactions, likely because it alleviates geometric constraints on cis binding. Thus, the balance between cis and trans interactions plays a role in controlling neural development.
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3
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Çoban B, Poppinga H, Rachad EY, Geurten B, Vasmer D, Rodriguez Jimenez FJ, Gadgil Y, Deimel SH, Alyagor I, Schuldiner O, Grunwald Kadow IC, Riemensperger TD, Widmann A, Fiala A. The caloric value of food intake structurally adjusts a neuronal mushroom body circuit mediating olfactory learning in Drosophila. Learn Mem 2024; 31:a053997. [PMID: 38862177 PMCID: PMC11199950 DOI: 10.1101/lm.053997.124] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2024] [Accepted: 04/10/2024] [Indexed: 06/13/2024]
Abstract
Associative learning enables the adaptive adjustment of behavioral decisions based on acquired, predicted outcomes. The valence of what is learned is influenced not only by the learned stimuli and their temporal relations, but also by prior experiences and internal states. In this study, we used the fruit fly Drosophila melanogaster to demonstrate that neuronal circuits involved in associative olfactory learning undergo restructuring during extended periods of low-caloric food intake. Specifically, we observed a decrease in the connections between specific dopaminergic neurons (DANs) and Kenyon cells at distinct compartments of the mushroom body. This structural synaptic plasticity was contingent upon the presence of allatostatin A receptors in specific DANs and could be mimicked optogenetically by expressing a light-activated adenylate cyclase in exactly these DANs. Importantly, we found that this rearrangement in synaptic connections influenced aversive, punishment-induced olfactory learning but did not impact appetitive, reward-based learning. Whether induced by prolonged low-caloric conditions or optogenetic manipulation of cAMP levels, this synaptic rearrangement resulted in a reduction of aversive associative learning. Consequently, the balance between positive and negative reinforcing signals shifted, diminishing the ability to learn to avoid odor cues signaling negative outcomes. These results exemplify how a neuronal circuit required for learning and memory undergoes structural plasticity dependent on prior experiences of the nutritional value of food.
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Affiliation(s)
- Büşra Çoban
- Molecular Neurobiology of Behavior, University of Göttingen, 37077 Göttingen, Germany
| | - Haiko Poppinga
- Molecular Neurobiology of Behavior, University of Göttingen, 37077 Göttingen, Germany
| | - El Yazid Rachad
- Molecular Neurobiology of Behavior, University of Göttingen, 37077 Göttingen, Germany
| | - Bart Geurten
- Department of Zoology, Otago University, Dunedin 9016, New Zealand
| | - David Vasmer
- Molecular Neurobiology of Behavior, University of Göttingen, 37077 Göttingen, Germany
| | | | - Yogesh Gadgil
- Molecular Neurobiology of Behavior, University of Göttingen, 37077 Göttingen, Germany
| | | | - Idan Alyagor
- Department of Molecular Cell Biology, Department of Molecular Neuroscience, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Oren Schuldiner
- Department of Molecular Cell Biology, Department of Molecular Neuroscience, Weizmann Institute of Science, Rehovot 7610001, Israel
| | | | | | - Annekathrin Widmann
- Molecular Neurobiology of Behavior, University of Göttingen, 37077 Göttingen, Germany
| | - André Fiala
- Molecular Neurobiology of Behavior, University of Göttingen, 37077 Göttingen, Germany
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4
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Tan JYK, Chew LY, Juhász G, Yu F. Interplay between autophagy and CncC regulates dendrite pruning in Drosophila. Proc Natl Acad Sci U S A 2024; 121:e2310740121. [PMID: 38408233 PMCID: PMC10927499 DOI: 10.1073/pnas.2310740121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2023] [Accepted: 01/26/2024] [Indexed: 02/28/2024] Open
Abstract
Autophagy is essential for the turnover of damaged organelles and long-lived proteins. It is responsible for many biological processes such as maintaining brain functions and aging. Impaired autophagy is often linked to neurodevelopmental and neurodegenerative diseases in humans. However, the role of autophagy in neuronal pruning during development remains poorly understood. Here, we report that autophagy regulates dendrite-specific pruning of ddaC sensory neurons in parallel to local caspase activation. Impaired autophagy causes the formation of ubiquitinated protein aggregates in ddaC neurons, dependent on the autophagic receptor Ref(2)P. Furthermore, the metabolic regulator AMP-activated protein kinase and the insulin-target of rapamycin pathway act upstream to regulate autophagy during dendrite pruning. Importantly, autophagy is required to activate the transcription factor CncC (Cap "n" collar isoform C), thereby promoting dendrite pruning. Conversely, CncC also indirectly affects autophagic activity via proteasomal degradation, as impaired CncC results in the inhibition of autophagy through sequestration of Atg8a into ubiquitinated protein aggregates. Thus, this study demonstrates the important role of autophagy in activating CncC prior to dendrite pruning, and further reveals an interplay between autophagy and CncC in neuronal pruning.
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Affiliation(s)
- Jue Yu Kelly Tan
- Temasek Life Sciences Laboratory, National University of Singapore, Singapore117604, Singapore
- Department of Biological Sciences, National University of Singapore, Singapore117543, Singapore
| | - Liang Yuh Chew
- Temasek Life Sciences Laboratory, National University of Singapore, Singapore117604, Singapore
- Department of Biological Sciences, National University of Singapore, Singapore117543, Singapore
| | - Gábor Juhász
- Department of Anatomy, Cell and Developmental Biology, Eötvös Loránd University, BudapestH-1117, Hungary
- Institute of Genetics, Biological Research Centre, SzegedH-6726, Hungary
| | - Fengwei Yu
- Temasek Life Sciences Laboratory, National University of Singapore, Singapore117604, Singapore
- Department of Biological Sciences, National University of Singapore, Singapore117543, Singapore
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5
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Alexander KD, Ramachandran S, Biswas K, Lambert CM, Russell J, Oliver DB, Armstrong W, Rettler M, Liu S, Doitsidou M, Bénard C, Walker AK, Francis MM. The homeodomain transcriptional regulator DVE-1 directs a program for synapse elimination during circuit remodeling. Nat Commun 2023; 14:7520. [PMID: 37980357 PMCID: PMC10657367 DOI: 10.1038/s41467-023-43281-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Accepted: 11/02/2023] [Indexed: 11/20/2023] Open
Abstract
The elimination of synapses during circuit remodeling is critical for brain maturation; however, the molecular mechanisms directing synapse elimination and its timing remain elusive. We show that the transcriptional regulator DVE-1, which shares homology with special AT-rich sequence-binding (SATB) family members previously implicated in human neurodevelopmental disorders, directs the elimination of juvenile synaptic inputs onto remodeling C. elegans GABAergic neurons. Juvenile acetylcholine receptor clusters and apposing presynaptic sites are eliminated during the maturation of wild-type GABAergic neurons but persist into adulthood in dve-1 mutants, producing heightened motor connectivity. DVE-1 localization to GABAergic nuclei is required for synapse elimination, consistent with DVE-1 regulation of transcription. Pathway analysis of putative DVE-1 target genes, proteasome inhibitor, and genetic experiments implicate the ubiquitin-proteasome system in synapse elimination. Together, our findings define a previously unappreciated role for a SATB family member in directing synapse elimination during circuit remodeling, likely through transcriptional regulation of protein degradation processes.
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Affiliation(s)
- Kellianne D Alexander
- Department of Neurobiology, University of Massachusetts Chan Medical School, Worcester, MA, USA
- Program in Neuroscience, University of Massachusetts Chan Medical School, Worcester, MA, USA
| | - Shankar Ramachandran
- Department of Neurobiology, University of Massachusetts Chan Medical School, Worcester, MA, USA
| | - Kasturi Biswas
- Department of Neurobiology, University of Massachusetts Chan Medical School, Worcester, MA, USA
- Program in Neuroscience, University of Massachusetts Chan Medical School, Worcester, MA, USA
| | - Christopher M Lambert
- Department of Neurobiology, University of Massachusetts Chan Medical School, Worcester, MA, USA
| | - Julia Russell
- Department of Neurobiology, University of Massachusetts Chan Medical School, Worcester, MA, USA
| | - Devyn B Oliver
- Department of Neurobiology, University of Massachusetts Chan Medical School, Worcester, MA, USA
- Program in Neuroscience, University of Massachusetts Chan Medical School, Worcester, MA, USA
| | - William Armstrong
- Department of Neurobiology, University of Massachusetts Chan Medical School, Worcester, MA, USA
| | - Monika Rettler
- Department of Neurobiology, University of Massachusetts Chan Medical School, Worcester, MA, USA
| | - Samuel Liu
- Department of Neurobiology, University of Massachusetts Chan Medical School, Worcester, MA, USA
- Program in Neuroscience, University of Massachusetts Chan Medical School, Worcester, MA, USA
| | - Maria Doitsidou
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, Scotland
| | - Claire Bénard
- Department of Neurobiology, University of Massachusetts Chan Medical School, Worcester, MA, USA
- Department of Biological Sciences, Université du Québec à Montréal, Quebec, Canada
| | - Amy K Walker
- Program in Molecular Medicine, University of Massachusetts Chan Medical School, Worcester, MA, USA
| | - Michael M Francis
- Department of Neurobiology, University of Massachusetts Chan Medical School, Worcester, MA, USA.
- Program in Neuroscience, University of Massachusetts Chan Medical School, Worcester, MA, USA.
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6
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Temporal control of neuronal wiring. Semin Cell Dev Biol 2023; 142:81-90. [PMID: 35644877 DOI: 10.1016/j.semcdb.2022.05.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Revised: 05/13/2022] [Accepted: 05/16/2022] [Indexed: 12/22/2022]
Abstract
Wiring an animal brain is a complex process involving a staggering number of cell-types born at different times and locations in the developing brain. Incorporation of these cells into precise circuits with high fidelity is critical for animal survival and behavior. Assembly of neuronal circuits is heavily dependent upon proper timing of wiring programs, requiring neurons to express specific sets of genes (sometimes transiently) at the right time in development. While cell-type specificity of genetic programs regulating wiring has been studied in detail, mechanisms regulating proper timing and coordination of these programs across cell-types are only just beginning to emerge. In this review, we discuss some temporal regulators of wiring programs and how their activity is controlled over time and space. A common feature emerges from these temporal regulators - they are induced by cell-extrinsic cues and control transcription factors capable of regulating a highly cell-type specific set of target genes. Target specificity in these contexts comes from cell-type specific transcription factors. We propose that the spatiotemporal specificity of wiring programs is controlled by the combinatorial activity of temporal programs and cell-type specific transcription factors. Going forward, a better understanding of temporal regulators will be key to understanding the mechanisms underlying brain wiring, and will be critical for the development of in vitro models like brain organoids.
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7
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Sakamura S, Hsu FY, Tsujita A, Abubaker MB, Chiang AS, Matsuno K. Ecdysone signaling determines lateral polarity and remodels neurites to form Drosophila's left-right brain asymmetry. Cell Rep 2023; 42:112337. [PMID: 37044096 DOI: 10.1016/j.celrep.2023.112337] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Revised: 02/01/2023] [Accepted: 03/19/2023] [Indexed: 04/14/2023] Open
Abstract
Left-right (LR) asymmetry of the brain is fundamental to its higher-order functions. The Drosophila brain's asymmetrical body (AB) consists of a structural pair arborized from AB neurons and is larger on the right side than the left. We find that the AB initially forms LR symmetrically and then develops LR asymmetrically by neurite remodeling that is specific to the left AB and is dynamin dependent. Additionally, neuronal ecdysone signaling inhibition randomizes AB laterality, suggesting that ecdysone signaling determines AB's LR polarity. Given that AB's LR asymmetry relates to memory formation, our research establishes AB as a valuable model for studying LR asymmetry and higher-order brain function relationships.
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Affiliation(s)
- So Sakamura
- Department of Biological Sciences, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan
| | - Fu-Yu Hsu
- Institute of Biotechnology, National Tsing Hua University, Hsinchu 30013, Taiwan; Brain Research Center, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Akari Tsujita
- Department of Biological Sciences, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan
| | | | - Ann-Shyn Chiang
- Institute of Biotechnology, National Tsing Hua University, Hsinchu 30013, Taiwan; Brain Research Center, National Tsing Hua University, Hsinchu 30013, Taiwan; Department of Biomedical Science and Environmental Biology, Kaohsiung Medical University, Kaohsiung 80780, Taiwan; Institute of Molecular and Genomic Medicine, National Health Research Institutes, Miaoli 35053, Taiwan; Graduate Institute of Clinical Medical Science, China Medical University, Taichung 40402, Taiwan; Kavli Institute for Brain and Mind, University of California San Diego, La Jolla, CA 92093-0526, USA
| | - Kenji Matsuno
- Department of Biological Sciences, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan.
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8
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Mayseless O, Shapira G, Rachad EY, Fiala A, Schuldiner O. Neuronal excitability as a regulator of circuit remodeling. Curr Biol 2023; 33:981-989.e3. [PMID: 36758544 PMCID: PMC10017263 DOI: 10.1016/j.cub.2023.01.032] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Revised: 10/18/2022] [Accepted: 01/17/2023] [Indexed: 02/11/2023]
Abstract
Postnatal remodeling of neuronal connectivity shapes mature nervous systems.1,2,3 The pruning of exuberant connections involves cell-autonomous and non-cell-autonomous mechanisms, such as neuronal activity. Indeed, experience-dependent competition sculpts various excitatory neuronal circuits.4,5,6,7,8,9 Moreover, activity has been shown to regulate growth cone motility and the stability of neurites and synaptic connections.10,11,12,13,14 However, whether inhibitory activity influences the remodeling of neuronal connectivity or how activity influences remodeling in systems in which competition is not clearly apparent is not fully understood. Here, we use the Drosophila mushroom body (MB) as a model to examine the role of neuronal activity in the developmental axon pruning of γ-Kenyon cells. The MB is a neuronal structure in insects, implicated in associative learning and memory,15,16 which receives mostly olfactory input from the antennal lobe.17,18 The MB circuit includes intrinsic neurons, called Kenyon cells (KCs), which receive inhibitory input from the GABAergic anterior paired lateral (APL) neuron among other inputs. The γ-KCs undergo stereotypic, steroid-hormone-dependent remodeling19,20 that involves the pruning of larval neurites followed by regrowth to form adult connections.21 We demonstrate that silencing neuronal activity is required for γ-KC pruning. Furthermore, we show that this is mechanistically achieved by cell-autonomous expression of the inward rectifying potassium channel 1 (irk1) combined with inhibition by APL neuron activity likely via GABA-B-R1 signaling. These results support the Hebbian-like rule "use it or lose it," where inhibition can destabilize connectivity and promote pruning while excitability stabilizes existing connections.
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Affiliation(s)
- Oded Mayseless
- Department of Molecular Cell Biology, Weizmann Institute of Science, 7610001 Rehovot, Israel
| | - Gal Shapira
- Department of Molecular Cell Biology, Weizmann Institute of Science, 7610001 Rehovot, Israel; Department of Molecular Neuroscience, Weizmann Institute of Science, 7610001 Rehovot, Israel
| | - El Yazid Rachad
- Department of Molecular Neurobiology of Behavior, Johann-Friedrich-Blumenbach-Institute for Zoology and Anthropology, University of Göttingen, 37077 Göttingen, Germany
| | - André Fiala
- Department of Molecular Neurobiology of Behavior, Johann-Friedrich-Blumenbach-Institute for Zoology and Anthropology, University of Göttingen, 37077 Göttingen, Germany
| | - Oren Schuldiner
- Department of Molecular Cell Biology, Weizmann Institute of Science, 7610001 Rehovot, Israel; Department of Molecular Neuroscience, Weizmann Institute of Science, 7610001 Rehovot, Israel.
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9
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Truman JW, Riddiford LM. Drosophila postembryonic nervous system development: a model for the endocrine control of development. Genetics 2023; 223:iyac184. [PMID: 36645270 PMCID: PMC9991519 DOI: 10.1093/genetics/iyac184] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Accepted: 12/13/2022] [Indexed: 01/17/2023] Open
Abstract
During postembryonic life, hormones, including ecdysteroids, juvenile hormones, insulin-like peptides, and activin/TGFβ ligands act to transform the larval nervous system into an adult version, which is a fine-grained mosaic of recycled larval neurons and adult-specific neurons. Hormones provide both instructional signals that make cells competent to undergo developmental change and timing cues to evoke these changes across the nervous system. While touching on all the above hormones, our emphasis is on the ecdysteroids, ecdysone and 20-hydroxyecdysone (20E). These are the prime movers of insect molting and metamorphosis and are involved in all phases of nervous system development, including neurogenesis, pruning, arbor outgrowth, and cell death. Ecdysteroids appear as a series of steroid peaks that coordinate the larval molts and the different phases of metamorphosis. Each peak directs a stereotyped cascade of transcription factor expression. The cascade components then direct temporal programs of effector gene expression, but the latter vary markedly according to tissue and life stage. The neurons read the ecdysteroid titer through various isoforms of the ecdysone receptor, a nuclear hormone receptor. For example, at metamorphosis the pruning of larval neurons is mediated through the B isoforms, which have strong activation functions, whereas subsequent outgrowth is mediated through the A isoform through which ecdysteroids play a permissive role to allow local tissue interactions to direct outgrowth. The major circulating ecdysteroid can also change through development. During adult development ecdysone promotes early adult patterning and differentiation while its metabolite, 20E, later evokes terminal adult differentiation.
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Affiliation(s)
- James W Truman
- Friday Harbor Laboratories, University of Washington, Friday Harbor, WA 98250, USA
- Department of Biology, University of Washington, Box 351800, Seattle, WA 98195, USA
| | - Lynn M Riddiford
- Friday Harbor Laboratories, University of Washington, Friday Harbor, WA 98250, USA
- Department of Biology, University of Washington, Box 351800, Seattle, WA 98195, USA
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10
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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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11
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Bu S, Lau SSY, Yong WL, Zhang H, Thiagarajan S, Bashirullah A, Yu F. Polycomb group genes are required for neuronal pruning in Drosophila. BMC Biol 2023; 21:33. [PMID: 36793038 PMCID: PMC9933400 DOI: 10.1186/s12915-023-01534-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Accepted: 02/02/2023] [Indexed: 02/17/2023] Open
Abstract
BACKGROUND Pruning that selectively eliminates unnecessary or incorrect neurites is required for proper wiring of the mature nervous system. During Drosophila metamorphosis, dendritic arbourization sensory neurons (ddaCs) and mushroom body (MB) γ neurons can selectively prune their larval dendrites and/or axons in response to the steroid hormone ecdysone. An ecdysone-induced transcriptional cascade plays a key role in initiating neuronal pruning. However, how downstream components of ecdysone signalling are induced remains not entirely understood. RESULTS Here, we identify that Scm, a component of Polycomb group (PcG) complexes, is required for dendrite pruning of ddaC neurons. We show that two PcG complexes, PRC1 and PRC2, are important for dendrite pruning. Interestingly, depletion of PRC1 strongly enhances ectopic expression of Abdominal B (Abd-B) and Sex combs reduced, whereas loss of PRC2 causes mild upregulation of Ultrabithorax and Abdominal A in ddaC neurons. Among these Hox genes, overexpression of Abd-B causes the most severe pruning defects, suggesting its dominant effect. Knockdown of the core PRC1 component Polyhomeotic (Ph) or Abd-B overexpression selectively downregulates Mical expression, thereby inhibiting ecdysone signalling. Finally, Ph is also required for axon pruning and Abd-B silencing in MB γ neurons, indicating a conserved function of PRC1 in two types of pruning. CONCLUSIONS This study demonstrates important roles of PcG and Hox genes in regulating ecdysone signalling and neuronal pruning in Drosophila. Moreover, our findings suggest a non-canonical and PRC2-independent role of PRC1 in Hox gene silencing during neuronal pruning.
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Affiliation(s)
- Shufeng Bu
- grid.4280.e0000 0001 2180 6431Temasek Life Sciences Laboratory, 1 Research Link, National University of Singapore, Singapore, 117604 Singapore ,grid.4280.e0000 0001 2180 6431Department of Biological Sciences, National University of Singapore, Singapore, 117543 Singapore
| | - Samuel Song Yuan Lau
- grid.4280.e0000 0001 2180 6431Temasek Life Sciences Laboratory, 1 Research Link, National University of Singapore, Singapore, 117604 Singapore
| | - Wei Lin Yong
- grid.4280.e0000 0001 2180 6431Temasek Life Sciences Laboratory, 1 Research Link, National University of Singapore, Singapore, 117604 Singapore
| | - Heng Zhang
- grid.4280.e0000 0001 2180 6431Temasek Life Sciences Laboratory, 1 Research Link, National University of Singapore, Singapore, 117604 Singapore
| | - Sasinthiran Thiagarajan
- grid.4280.e0000 0001 2180 6431Temasek Life Sciences Laboratory, 1 Research Link, National University of Singapore, Singapore, 117604 Singapore ,grid.4280.e0000 0001 2180 6431Department of Biological Sciences, National University of Singapore, Singapore, 117543 Singapore
| | - Arash Bashirullah
- grid.14003.360000 0001 2167 3675Division of Pharmaceutical Sciences, University of Wisconsin-Madison, Madison, WI 53705-2222 USA
| | - Fengwei Yu
- Temasek Life Sciences Laboratory, 1 Research Link, National University of Singapore, Singapore, 117604, Singapore. .,Department of Biological Sciences, National University of Singapore, Singapore, 117543, Singapore.
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12
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Kozlov EN, Tokmatcheva EV, Khrustaleva AM, Grebenshchikov ES, Deev RV, Gilmutdinov RA, Lebedeva LA, Zhukova M, Savvateeva-Popova EV, Schedl P, Shidlovskii YV. Long-Term Memory Formation in Drosophila Depends on the 3'UTR of CPEB Gene orb2. Cells 2023; 12:cells12020318. [PMID: 36672258 PMCID: PMC9856895 DOI: 10.3390/cells12020318] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Revised: 12/30/2022] [Accepted: 01/12/2023] [Indexed: 01/18/2023] Open
Abstract
Activation of local translation in neurites in response to stimulation is an important step in the formation of long-term memory (LTM). CPEB proteins are a family of translation factors involved in LTM formation. The Drosophila CPEB protein Orb2 plays an important role in the development and function of the nervous system. Mutations of the coding region of the orb2 gene have previously been shown to impair LTM formation. We found that a deletion of the 3'UTR of the orb2 gene similarly results in loss of LTM in Drosophila. As a result of the deletion, the content of the Orb2 protein remained the same in the neuron soma, but significantly decreased in synapses. Using RNA immunoprecipitation followed by high-throughput sequencing, we detected more than 6000 potential Orb2 mRNA targets expressed in the Drosophila brain. Importantly, deletion of the 3'UTR of orb2 mRNA also affected the localization of the Csp, Pyd, and Eya proteins, which are encoded by putative mRNA targets of Orb2. Therefore, the 3'UTR of the orb2 mRNA is important for the proper localization of Orb2 and other proteins in synapses of neurons and the brain as a whole, providing a molecular basis for LTM formation.
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Affiliation(s)
- Eugene N. Kozlov
- Laboratory of Gene Expression Regulation in Development, Institute of Gene Biology, Russian Academy of Sciences, 119334 Moscow, Russia
| | - Elena V. Tokmatcheva
- Institute of Physiology, Russian Academy of Sciences, 188680 St. Petersburg, Russia
| | - Anastasia M. Khrustaleva
- Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Institute of Gene Biology, Russian Academy of Sciences, 119334 Moscow, Russia
| | - Eugene S. Grebenshchikov
- Department of Biology and General Genetics, Sechenov First Moscow State Medical University (Sechenov University), 119992 Moscow, Russia
| | - Roman V. Deev
- Laboratory of Gene Expression Regulation in Development, Institute of Gene Biology, Russian Academy of Sciences, 119334 Moscow, Russia
| | - Rudolf A. Gilmutdinov
- Laboratory of Gene Expression Regulation in Development, Institute of Gene Biology, Russian Academy of Sciences, 119334 Moscow, Russia
| | - Lyubov A. Lebedeva
- Laboratory of Gene Expression Regulation in Development, Institute of Gene Biology, Russian Academy of Sciences, 119334 Moscow, Russia
| | - Mariya Zhukova
- Laboratory of Gene Expression Regulation in Development, Institute of Gene Biology, Russian Academy of Sciences, 119334 Moscow, Russia
| | | | - Paul Schedl
- Laboratory of Gene Expression Regulation in Development, Institute of Gene Biology, Russian Academy of Sciences, 119334 Moscow, Russia
- Department of Molecular Biology, Princeton University, Princeton University, Princeton, NJ 08544-1014, USA
| | - Yulii V. Shidlovskii
- Laboratory of Gene Expression Regulation in Development, Institute of Gene Biology, Russian Academy of Sciences, 119334 Moscow, Russia
- Department of Biology and General Genetics, Sechenov First Moscow State Medical University (Sechenov University), 119992 Moscow, Russia
- Correspondence:
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13
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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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14
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Rylee J, Mahato S, Aldrich J, Bergh E, Sizemore B, Feder LE, Grega S, Helms K, Maar M, Britt SG, Zelhof AC. A TRiP RNAi screen to identify molecules necessary for Drosophila photoreceptor differentiation. G3 GENES|GENOMES|GENETICS 2022; 12:6758253. [DOI: 10.1093/g3journal/jkac257] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Accepted: 09/15/2022] [Indexed: 11/06/2022]
Abstract
Abstract
Drosophila rhabdomeric terminal photoreceptor differentiation is an extended process taking several days to complete. Following ommatidial patterning by the morphogenetic furrow, photoreceptors are sequentially recruited and specified, and terminal differentiation begins. Key events of terminal differentiation include the establishment of apical and basolateral domains, rhabdomere and stalk formation, inter-rhabdomeral space formation, and expression of phototransduction machinery. While many key regulators of these processes have been identified, the complete network of transcription factors to downstream effector molecules necessary for regulating each of these major events remains incomplete. Here, we report an RNAi screen to identify additional molecules and cellular pathways required for photoreceptor terminal differentiation. First, we tested several eye-specific GAL4 drivers for correct spatial and temporal specificity and identified Pph13-GAL4 as the most appropriate GAL4 line for our screen. We screened lines available through the Transgenic RNAi Project and isolated lines that when combined with Pph13-GAL4 resulted in the loss of the deep pseudopupil, as a readout for abnormal differentiation. In the end, we screened 6,189 lines, representing 3,971 genes, and have identified 64 genes, illuminating potential new regulatory molecules and cellular pathways for the differentiation and organization of Drosophila rhabdomeric photoreceptors.
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Affiliation(s)
- Johnathan Rylee
- Department of Biology, Indiana University , Bloomington, IN 47405, USA
| | - Simpla Mahato
- Department of Biology, Indiana University , Bloomington, IN 47405, USA
| | - John Aldrich
- Department of Neurology and Ophthalmology, Dell Medical School, University of Texas , Austin, TX 78712, USA
| | - Emma Bergh
- Department of Biology, Indiana University , Bloomington, IN 47405, USA
| | - Brandon Sizemore
- Department of Biology, Indiana University , Bloomington, IN 47405, USA
| | - Lauren E Feder
- Department of Biology, Indiana University , Bloomington, IN 47405, USA
| | - Shaun Grega
- Department of Biology, Indiana University , Bloomington, IN 47405, USA
| | - Kennedy Helms
- Department of Biology, Indiana University , Bloomington, IN 47405, USA
| | - Megan Maar
- Department of Biology, Indiana University , Bloomington, IN 47405, USA
| | - Steven G Britt
- Department of Neurology and Ophthalmology, Dell Medical School, University of Texas , Austin, TX 78712, USA
| | - Andrew C Zelhof
- Department of Biology, Indiana University , Bloomington, IN 47405, USA
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15
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Emerging Role of Neuron-Glia in Neurological Disorders: At a Glance. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2022; 2022:3201644. [PMID: 36046684 PMCID: PMC9423989 DOI: 10.1155/2022/3201644] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Accepted: 08/05/2022] [Indexed: 11/18/2022]
Abstract
Based on the diverse physiological influence, the impact of glial cells has become much more evident on neurological illnesses, resulting in the origins of many diseases appearing to be more convoluted than previously happened. Since neurological disorders are often random and unknown, hence the construction of animal models is difficult to build, representing a small fraction of people with a gene mutation. As a result, an immediate necessity is grown to work within in vitro techniques for examining these illnesses. As the scientific community recognizes cell-autonomous contributions to a variety of central nervous system illnesses, therapeutic techniques involving stem cells for treating neurological diseases are gaining traction. The use of stem cells derived from a variety of sources is increasingly being used to replace both neuronal and glial tissue. The brain's energy demands necessitate the reliance of neurons on glial cells in order for it to function properly. Furthermore, glial cells have diverse functions in terms of regulating their own metabolic activities, as well as collaborating with neurons via secreted signaling or guidance molecules, forming a complex network of neuron-glial connections in health and sickness. Emerging data reveals that metabolic changes in glial cells can cause morphological and functional changes in conjunction with neuronal dysfunction under disease situations, highlighting the importance of neuron-glia interactions in the pathophysiology of neurological illnesses. In this context, it is required to improve our understanding of disease mechanisms and create potential novel therapeutics. According to research, synaptic malfunction is one of the features of various mental diseases, and glial cells are acting as key ingredients not only in synapse formation, growth, and plasticity but also in neuroinflammation and synaptic homeostasis which creates critical physiological capacity in the focused sensory system. The goal of this review article is to elaborate state-of-the-art information on a few glial cell types situated in the central nervous system (CNS) and highlight their role in the onset and progression of neurological disorders.
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16
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Poppinga H, Çoban B, Meltzer H, Mayseless O, Widmann A, Schuldiner O, Fiala A. Pruning deficits of the developing Drosophila mushroom body result in mild impairment in associative odour learning and cause hyperactivity. Open Biol 2022; 12:220096. [PMID: 36128716 PMCID: PMC9490343 DOI: 10.1098/rsob.220096] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The principles of how brain circuits establish themselves during development are largely conserved across animal species. Connections made during embryonic development that are appropriate for an early life stage are frequently remodelled later in ontogeny via pruning and subsequent regrowth to generate adult-specific connectivity. The mushroom body of the fruit fly Drosophila melanogaster is a well-established model circuit for examining the cellular mechanisms underlying neurite remodelling. This central brain circuit integrates sensory information with learned and innate valences to adaptively instruct behavioural decisions. Thereby, the mushroom body organizes adaptive behaviour, such as associative learning. However, little is known about the specific aspects of behaviour that require mushroom body remodelling. Here, we used genetic interventions to prevent the intrinsic neurons of the larval mushroom body (γ-type Kenyon cells) from remodelling. We asked to what degree remodelling deficits resulted in impaired behaviour. We found that deficits caused hyperactivity and mild impairment in differential aversive olfactory learning, but not appetitive learning. Maintenance of circadian rhythm and sleep were not affected. We conclude that neurite pruning and regrowth of γ-type Kenyon cells is not required for the establishment of circuits that mediate associative odour learning per se, but it does improve distinct learning tasks.
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Affiliation(s)
- Haiko Poppinga
- Department of Molecular Neurobiology of Behaviour, University of Göttingen, Julia-Lermontowa-Weg 3, 37077 Göttingen, Germany
| | - Büşra Çoban
- Department of Molecular Neurobiology of Behaviour, University of Göttingen, Julia-Lermontowa-Weg 3, 37077 Göttingen, Germany
| | - Hagar Meltzer
- Departments for Molecular Cell Biology and Molecular Neuroscience, Weizmann Institute of Science, Ullmann Building of Life Sciences, Rehovot 7610001, Israel
| | - Oded Mayseless
- Departments for Molecular Cell Biology and Molecular Neuroscience, Weizmann Institute of Science, Ullmann Building of Life Sciences, Rehovot 7610001, Israel
| | - Annekathrin Widmann
- Department of Molecular Neurobiology of Behaviour, University of Göttingen, Julia-Lermontowa-Weg 3, 37077 Göttingen, Germany
| | - Oren Schuldiner
- Departments for Molecular Cell Biology and Molecular Neuroscience, Weizmann Institute of Science, Ullmann Building of Life Sciences, Rehovot 7610001, Israel
| | - André Fiala
- Department of Molecular Neurobiology of Behaviour, University of Göttingen, Julia-Lermontowa-Weg 3, 37077 Göttingen, Germany
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17
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Yuh Chew L, He J, Wong JJL, Li S, Yu F. AMPK activates the Nrf2-Keap1 pathway to govern dendrite pruning via the insulin pathway in Drosophila. Development 2022; 149:275791. [DOI: 10.1242/dev.200536] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Accepted: 06/16/2022] [Indexed: 11/20/2022]
Abstract
ABSTRACT
During Drosophila metamorphosis, the ddaC dendritic arborisation sensory neurons selectively prune their larval dendrites in response to steroid hormone ecdysone signalling. The Nrf2-Keap1 pathway acts downstream of ecdysone signalling to promote proteasomal degradation and thereby dendrite pruning. However, how the Nrf2-Keap1 pathway is activated remains largely unclear. Here, we demonstrate that the metabolic regulator AMP-activated protein kinase (AMPK) plays a cell-autonomous role in dendrite pruning. Importantly, AMPK is required for Mical and Headcase expression and for activation of the Nrf2-Keap1 pathway. We reveal that AMPK promotes the Nrf2-Keap1 pathway and dendrite pruning partly via inhibition of the insulin pathway. Moreover, the AMPK-insulin pathway is required for ecdysone signalling to activate the Nrf2-Keap1 pathway during dendrite pruning. Overall, this study reveals an important mechanism whereby ecdysone signalling activates the Nrf2-Keap1 pathway via the AMPK-insulin pathway to promote dendrite pruning, and further suggests that during the nonfeeding prepupal stage metabolic alterations lead to activation of the Nrf2-Keap1 pathway and dendrite pruning.
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Affiliation(s)
- Liang Yuh Chew
- 1 Research Link, National University of Singapore 1 Temasek Life Sciences Laboratory , , 117604 , Singapore
- National University of Singapore 2 Department of Biological Sciences , , 117543 , Singapore
| | - Jianzheng He
- 1 Research Link, National University of Singapore 1 Temasek Life Sciences Laboratory , , 117604 , Singapore
| | - Jack Jing Lin Wong
- 1 Research Link, National University of Singapore 1 Temasek Life Sciences Laboratory , , 117604 , Singapore
| | - Sheng Li
- Institute of Insect Science and Technology & School of Life Sciences, South China Normal University 3 Guangdong Provincial Key Laboratory of Insect Developmental Biology and Applied Technology , , Guangzhou 510631 , China
| | - Fengwei Yu
- 1 Research Link, National University of Singapore 1 Temasek Life Sciences Laboratory , , 117604 , Singapore
- National University of Singapore 2 Department of Biological Sciences , , 117543 , Singapore
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18
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Post-transcriptional regulation of transcription factor codes in immature neurons drives neuronal diversity. Cell Rep 2022; 39:110992. [PMID: 35767953 PMCID: PMC9479746 DOI: 10.1016/j.celrep.2022.110992] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Revised: 04/15/2022] [Accepted: 06/01/2022] [Indexed: 12/31/2022] Open
Abstract
How the vast array of neuronal diversity is generated remains an unsolved problem. Here, we investigate how 29 morphologically distinct leg motoneurons are generated from a single stem cell in Drosophila. We identify 19 transcription factor (TF) codes expressed in immature motoneurons just before their morphological differentiation. Using genetic manipulations and a computational tool, we demonstrate that the TF codes are progressively established in immature motoneurons according to their birth order. Comparing RNA and protein expression patterns of multiple TFs reveals that post-transcriptional regulation plays an essential role in shaping these TF codes. Two RNA-binding proteins, Imp and Syp, expressed in opposing gradients in immature motoneurons, control the translation of multiple TFs. The varying sensitivity of TF mRNAs to the opposing gradients of Imp and Syp in immature motoneurons decrypts these gradients into distinct TF codes, establishing the connectome between motoneuron axons and their target muscles.
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19
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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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20
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Lai YW, Miyares RL, Liu LY, Chu SY, Lee T, Yu HH. Hormone-controlled changes in the differentiation state of post-mitotic neurons. Curr Biol 2022; 32:2341-2348.e3. [PMID: 35508173 DOI: 10.1016/j.cub.2022.04.027] [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: 11/23/2021] [Revised: 03/22/2022] [Accepted: 04/12/2022] [Indexed: 11/16/2022]
Abstract
While we think of neurons as having a fixed identity, many show spectacular plasticity.1-10 Metamorphosis drives massive changes in the fly brain;11,12 neurons that persist into adulthood often change in response to the steroid hormone ecdysone.13,14 Besides driving remodeling,11-14 ecdysone signaling can also alter the differentiation status of neurons.7,15 The three sequentially born subtypes of mushroom body (MB) Kenyon cells (γ, followed by α'/β', and finally α/β)16 serve as a model of temporal fating.17-21 γ neurons are also used as a model of remodeling during metamorphosis. As γ neurons are the only functional Kenyon cells in the larval brain, they serve the function of all three adult subtypes. Correspondingly, larval γ neurons have a similar morphology to α'/β' and α/β neurons-their axons project dorsally and medially. During metamorphosis, γ neurons remodel to form a single medial projection. Both temporal fate changes and defects in remodeling therefore alter γ-neuron morphology in similar ways. Mamo, a broad-complex, tramtrack, and bric-à-brac/poxvirus and zinc finger (BTB/POZ) transcription factor critical for temporal specification of α'/β' neurons,18,19 was recently described as essential for γ remodeling.22 In a previous study, we noticed a change in the number of adult Kenyon cells expressing γ-specific markers when mamo was manipulated.18 These data implied a role for Mamo in γ-neuron fate specification, yet mamo is not expressed in γ neurons until pupariation,18,22 well past γ specification. This indicates that mamo has a later role in ensuring that γ neurons express the correct Kenyon cell subtype-specific genes in the adult brain.
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Affiliation(s)
- Yen-Wei Lai
- Institute of Cellular and Organismic Biology, Academia Sinica, Academia Road, Taipei 11529, Taiwan; Institute of Molecular and Cellular Biology, College of Life Science, National Taiwan University, Roosevelt Road, Taipei 10617, Taiwan
| | - Rosa L Miyares
- Howard Hughes Medical Institute, Janelia Research Campus, Helix Drive, Ashburn, VA 20147, USA
| | - Ling-Yu Liu
- Howard Hughes Medical Institute, Janelia Research Campus, Helix Drive, Ashburn, VA 20147, USA
| | - Sao-Yu Chu
- Institute of Cellular and Organismic Biology, Academia Sinica, Academia Road, Taipei 11529, Taiwan
| | - Tzumin Lee
- Howard Hughes Medical Institute, Janelia Research Campus, Helix Drive, Ashburn, VA 20147, USA.
| | - Hung-Hsiang Yu
- Institute of Cellular and Organismic Biology, Academia Sinica, Academia Road, Taipei 11529, Taiwan.
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21
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Boulanger A, Dura JM. Neuron-glia crosstalk in neuronal remodeling and degeneration: Neuronal signals inducing glial cell phagocytic transformation in Drosophila. Bioessays 2022; 44:e2100254. [PMID: 35315125 DOI: 10.1002/bies.202100254] [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: 10/25/2021] [Revised: 03/04/2022] [Accepted: 03/07/2022] [Indexed: 11/09/2022]
Abstract
Neuronal remodeling is a conserved mechanism that eliminates unwanted neurites and can include the loss of cell bodies. In these processes, a key role for glial cells in events from synaptic pruning to neuron elimination has been clearly identified in the last decades. Signals sent from dying neurons or neurites to be removed are received by appropriate glial cells. After receiving these signals, glial cells infiltrate degenerating sites and then, engulf and clear neuronal debris through phagocytic mechanisms. There are few identified or proposed signals and receptors involved in neuron-glia crosstalk, which induces the transformation of glial cells to phagocytes during neuronal remodeling in Drosophila. Many of these signaling pathways are conserved in mammals. Here, we particularly emphasize the role of Orion, a recently identified neuronal CX3 C chemokine-like secreted protein, which induces astrocyte infiltration and engulfment during mushroom body neuronal remodeling. Although, chemokine signaling was not described previously in insects we propose that chemokine-like involvement in neuron/glial cell interaction is an evolutionarily ancient mechanism.
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Affiliation(s)
- Ana Boulanger
- IGH, Université de Montpellier, CNRS, Montpellier, France
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22
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A global timing mechanism regulates cell-type-specific wiring programmes. Nature 2022; 603:112-118. [PMID: 35197627 DOI: 10.1038/s41586-022-04418-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Accepted: 01/10/2022] [Indexed: 01/04/2023]
Abstract
The assembly of neural circuits is dependent on precise spatiotemporal expression of cell recognition molecules1-5. Factors controlling cell type specificity have been identified6-8, but how timing is determined remains unknown. Here we describe induction of a cascade of transcription factors by a steroid hormone (ecdysone) in all fly visual system neurons spanning target recognition and synaptogenesis. We demonstrate through single-cell sequencing that the ecdysone pathway regulates the expression of a common set of targets required for synaptic maturation and cell-type-specific targets enriched for cell-surface proteins regulating wiring specificity. Transcription factors in the cascade regulate the expression of the same wiring genes in complex ways, including activation in one cell type and repression in another. We show that disruption of the ecdysone pathway generates specific defects in dendritic and axonal processes and synaptic connectivity, with the order of transcription factor expression correlating with sequential steps in wiring. We also identify shared targets of a cell-type-specific transcription factor and the ecdysone pathway that regulate specificity. We propose that neurons integrate a global temporal transcriptional module with cell-type-specific transcription factors to generate different cell-type-specific patterns of cell recognition molecules regulating wiring.
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23
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Schilder BM, Navarro E, Raj T. Multi-omic insights into Parkinson's Disease: From genetic associations to functional mechanisms. Neurobiol Dis 2021; 163:105580. [PMID: 34871738 PMCID: PMC10101343 DOI: 10.1016/j.nbd.2021.105580] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Revised: 11/17/2021] [Accepted: 12/02/2021] [Indexed: 02/07/2023] Open
Abstract
Genome-Wide Association Studies (GWAS) have elucidated the genetic components of Parkinson's Disease (PD). However, because the vast majority of GWAS association signals fall within non-coding regions, translating these results into an interpretable, mechanistic understanding of the disease etiology remains a major challenge in the field. In this review, we provide an overview of the approaches to prioritize putative causal variants and genes as well as summarise the primary findings of previous studies. We then discuss recent efforts to integrate multi-omics data to identify likely pathogenic cell types and biological pathways implicated in PD pathogenesis. We have compiled full summary statistics of cell-type, tissue, and phentoype enrichment analyses from multiple studies of PD GWAS and provided them in a standardized format as a resource for the research community (https://github.com/RajLabMSSM/PD_omics_review). Finally, we discuss the experimental, computational, and conceptual advances that will be necessary to fully elucidate the effects of functional variants and genes on cellular dysregulation and disease risk.
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Affiliation(s)
- Brian M Schilder
- Nash Family Department of Neuroscience & Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, United States; Ronald M. Loeb Center for Alzheimer's disease, Icahn School of Medicine at Mount Sinai, New York, NY, United States; Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, United States; Icahn Institute for Data Science and Genomic Technology, Icahn School of Medicine at Mount Sinai, New York, NY, United States; Estelle and Daniel Maggin Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, NY, United States; Department of Brain Sciences, Faculty of Medicine, Imperial College London, London, United Kingdom; UK Dementia Research Institute at Imperial College London, London, United Kingdom.
| | - Elisa Navarro
- Nash Family Department of Neuroscience & Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, United States; Ronald M. Loeb Center for Alzheimer's disease, Icahn School of Medicine at Mount Sinai, New York, NY, United States; Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, United States; Icahn Institute for Data Science and Genomic Technology, Icahn School of Medicine at Mount Sinai, New York, NY, United States; Estelle and Daniel Maggin Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, NY, United States; Sección Departamental de Bioquímica y Biología Molecular, Facultad de Medicina, Universidad Complutense de Madrid, Madrid, Spain
| | - Towfique Raj
- Nash Family Department of Neuroscience & Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, United States; Ronald M. Loeb Center for Alzheimer's disease, Icahn School of Medicine at Mount Sinai, New York, NY, United States; Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, United States; Icahn Institute for Data Science and Genomic Technology, Icahn School of Medicine at Mount Sinai, New York, NY, United States; Estelle and Daniel Maggin Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, NY, United States.
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24
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Chen D, McManus CE, Radmanesh B, Matzat LH, Lei EP. Temporal inhibition of chromatin looping and enhancer accessibility during neuronal remodeling. Nat Commun 2021; 12:6366. [PMID: 34737269 PMCID: PMC8568962 DOI: 10.1038/s41467-021-26628-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Accepted: 10/14/2021] [Indexed: 11/24/2022] Open
Abstract
During development, looping of an enhancer to a promoter is frequently observed in conjunction with temporal and tissue-specific transcriptional activation. The chromatin insulator-associated protein Alan Shepard (Shep) promotes Drosophila post-mitotic neuronal remodeling by repressing transcription of master developmental regulators, such as brain tumor (brat), specifically in maturing neurons. Since insulator proteins can promote looping, we hypothesized that Shep antagonizes brat promoter interaction with an as yet unidentified enhancer. Using chromatin conformation capture and reporter assays, we identified two enhancer regions that increase in looping frequency with the brat promoter specifically in pupal brains after Shep depletion. The brat promoters and enhancers function independently of Shep, ruling out direct repression of these elements. Moreover, ATAC-seq in isolated neurons demonstrates that Shep restricts chromatin accessibility of a key brat enhancer as well as other enhancers genome-wide in remodeling pupal but not larval neurons. These enhancers are enriched for chromatin targets of Shep and are located at Shep-inhibited genes, suggesting direct Shep inhibition of enhancer accessibility and gene expression during neuronal remodeling. Our results provide evidence for temporal regulation of chromatin looping and enhancer accessibility during neuronal maturation.
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Affiliation(s)
- Dahong Chen
- Nuclear Organization and Gene Expression Section, Bethesda, MD, USA
- Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, 9000 Rockville Pike, Bethesda, MD, 20892, USA
| | - Catherine E McManus
- Nuclear Organization and Gene Expression Section, Bethesda, MD, USA
- Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, 9000 Rockville Pike, Bethesda, MD, 20892, USA
| | - Behram Radmanesh
- Laboratory of Cellular and Developmental Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, 9000 Rockville Pike, Bethesda, MD, USA
| | - Leah H Matzat
- Nuclear Organization and Gene Expression Section, Bethesda, MD, USA
- Laboratory of Cellular and Developmental Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, 9000 Rockville Pike, Bethesda, MD, USA
| | - Elissa P Lei
- Nuclear Organization and Gene Expression Section, Bethesda, MD, USA.
- Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, 9000 Rockville Pike, Bethesda, MD, 20892, USA.
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25
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Li Y, Tsim KWK, Wang WX. Copper promoting oyster larval growth and settlement: Molecular insights from RNA-seq. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 784:147159. [PMID: 33894613 DOI: 10.1016/j.scitotenv.2021.147159] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Revised: 04/10/2021] [Accepted: 04/11/2021] [Indexed: 06/12/2023]
Abstract
As a cofactor of key enzymes, Cu is required in living organisms, although Cu levels in the natural environment are typically low. In this study, the promotion of growth and settlement on the larvae of oyster Crassostrea angulata was observed at an environmentally relevant concentration (10 μg/L Cu). Interestingly, Cu accumulation in the soft tissue of oyster larvae increased during the larval development and exhibited a sharp increase at the late pelagic stage. With the help of RNA-seq, we constructed a high-quality transcriptional database of the oyster C. angulata larvae (24,257 genes with an average length of 1594 bp) via de novo assembly, which provided the basic molecular changes during the larval development. Network analysis of five early developmental stages and differential expression under Cu exposure were integrated to examine the roles of Cu in oyster larvae. Our molecular analysis demonstrated that both ion channels and organic transporters contributed to Cu internalization from the external environment, including zinc transporters and amino acid transporters. The followed distribution of Cu across cells was achieved by ATP7A, the circulatory system, and the Cu transporters (CTRs). Cu exposure enhanced the ribosome and the calcium binding proteins with a higher rate of translation and shell formation, giving rise to faster growth of oyster larvae. Furthermore, Cu facilitated the settling process by upregulating the chitin binding genes and then promoting the formation of the proteinaceous matrix between larvae and substrate. Our study presents the molecular basis for Cu promotion (i.e., hormesis) effects on oyster larval growth and settlement.
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Affiliation(s)
- Yunlong Li
- Division of Life Science and Hong Kong Branch of the Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), The Hong Kong University of Science and Technology, Kowloon, Hong Kong, China; School of Energy and Environment and State Key Laboratory of Marine Pollution, City University of Hong Kong, Kowloon, Hong Kong, China
| | - Karl Wah-Keung Tsim
- Division of Life Science and Hong Kong Branch of the Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), The Hong Kong University of Science and Technology, Kowloon, Hong Kong, China
| | - Wen-Xiong Wang
- School of Energy and Environment and State Key Laboratory of Marine Pollution, City University of Hong Kong, Kowloon, Hong Kong, China; Research Centre for the Oceans and Human Health, City University of Hong Kong Shenzhen Research Institute, Shenzhen 518057, China.
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26
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Chew LY, Zhang H, He J, Yu F. The Nrf2-Keap1 pathway is activated by steroid hormone signaling to govern neuronal remodeling. Cell Rep 2021; 36:109466. [PMID: 34348164 DOI: 10.1016/j.celrep.2021.109466] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Revised: 06/09/2021] [Accepted: 07/08/2021] [Indexed: 12/30/2022] Open
Abstract
The evolutionarily conserved Nrf2-Keap1 pathway is a key antioxidant response pathway that protects cells/organisms against detrimental effects of oxidative stress. Impaired Nrf2 function is associated with cancer and neurodegenerative diseases in humans. However, the function of the Nrf2-Keap1 pathway in the developing nervous systems has not been established. Here we demonstrate a cell-autonomous role of the Nrf2-Keap1 pathway, composed of CncC/Nrf2, Keap1, and MafS, in governing neuronal remodeling during Drosophila metamorphosis. Nrf2-Keap1 signaling is activated downstream of the steroid hormone ecdysone. Mechanistically, the Nrf2-Keap1 pathway is activated via cytoplasmic-to-nuclear translocation of CncC in an importin- and ecdysone-signaling-dependent manner. Moreover, Nrf2-Keap1 signaling regulates dendrite pruning independent of its canonical antioxidant response pathway, acting instead through proteasomal degradation. This study reveals an epistatic link between the Nrf2-Keap1 pathway and steroid hormone signaling and demonstrates an antioxidant-independent but proteasome-dependent role of the Nrf2-Keap1 pathway in neuronal remodeling.
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Affiliation(s)
- Liang Yuh Chew
- Temasek Life Sciences Laboratory, 1 Research Link, National University of Singapore, Singapore 117604, Singapore; Department of Biological Sciences, National University of Singapore, Singapore 117543, Singapore
| | - Heng Zhang
- Temasek Life Sciences Laboratory, 1 Research Link, National University of Singapore, Singapore 117604, Singapore
| | - Jianzheng He
- Temasek Life Sciences Laboratory, 1 Research Link, National University of Singapore, Singapore 117604, Singapore
| | - Fengwei Yu
- Temasek Life Sciences Laboratory, 1 Research Link, National University of Singapore, Singapore 117604, Singapore; Department of Biological Sciences, National University of Singapore, Singapore 117543, Singapore.
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27
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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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28
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Pavón-Romero GF, Serrano-Pérez NH, García-Sánchez L, Ramírez-Jiménez F, Terán LM. Neuroimmune Pathophysiology in Asthma. Front Cell Dev Biol 2021; 9:663535. [PMID: 34055794 PMCID: PMC8155297 DOI: 10.3389/fcell.2021.663535] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Accepted: 04/15/2021] [Indexed: 12/26/2022] Open
Abstract
Asthma is a chronic inflammation of lower airway disease, characterized by bronchial hyperresponsiveness. Type I hypersensitivity underlies all atopic diseases including allergic asthma. However, the role of neurotransmitters (NT) and neuropeptides (NP) in this disease has been less explored in comparison with inflammatory mechanisms. Indeed, the airway epithelium contains pulmonary neuroendocrine cells filled with neurotransmitters (serotonin and GABA) and neuropeptides (substance P[SP], neurokinin A [NKA], vasoactive intestinal peptide [VIP], Calcitonin-gene related peptide [CGRP], and orphanins-[N/OFQ]), which are released after allergen exposure. Likewise, the autonomic airway fibers produce acetylcholine (ACh) and the neuropeptide Y(NPY). These NT/NP differ in their effects; SP, NKA, and serotonin exert pro-inflammatory effects, whereas VIP, N/OFQ, and GABA show anti-inflammatory activity. However, CGPR and ACh have dual effects. For example, the ACh-M3 axis induces goblet cell metaplasia, extracellular matrix deposition, and bronchoconstriction; the CGRP-RAMP1 axis enhances Th2 and Th9 responses; and the SP-NK1R axis promotes the synthesis of chemokines in eosinophils, mast cells, and neutrophils. In contrast, the ACh-α7nAChR axis in ILC2 diminishes the synthesis of TNF-α, IL-1, and IL-6, attenuating lung inflammation whereas, VIP-VPAC1, N/OFQ-NOP axes cause bronchodilation and anti-inflammatory effects. Some NT/NP as 5-HT and NKA could be used as biomarkers to monitor asthma patients. In fact, the asthma treatment based on inhaled corticosteroids and anticholinergics blocks M3 and TRPV1 receptors. Moreover, the administration of experimental agents such as NK1R/NK2R antagonists and exogenous VIP decrease inflammatory mediators, suggesting that regulating the effects of NT/NP represents a potential novel approach for the treatment of asthma.
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Affiliation(s)
| | | | | | | | - Luis M. Terán
- Department of Immunogenetics and Allergy, Instituto Nacional Enfermedades Respiratorias Ismael Cosío Villegas, Mexico City, Mexico
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29
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Leinwand SG, Scott K. Juvenile hormone drives the maturation of spontaneous mushroom body neural activity and learned behavior. Neuron 2021; 109:1836-1847.e5. [PMID: 33915110 DOI: 10.1016/j.neuron.2021.04.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Revised: 03/26/2021] [Accepted: 04/07/2021] [Indexed: 12/21/2022]
Abstract
Mature behaviors emerge from neural circuits sculpted by genetic programs and spontaneous and evoked neural activity. However, how neural activity is refined to drive maturation of learned behavior remains poorly understood. Here, we explore how transient hormonal signaling coordinates a neural activity state transition and maturation of associative learning. We identify spontaneous, asynchronous activity in a Drosophila learning and memory brain region, the mushroom body. This activity declines significantly over the first week of adulthood. Moreover, this activity is generated cell-autonomously via Cacophony voltage-gated calcium channels in a single cell type, α'/β' Kenyon cells. Juvenile hormone, a crucial developmental regulator, acts transiently in α'/β' Kenyon cells during a young adult sensitive period to downregulate spontaneous activity and enable subsequent enhanced learning. Hormone signaling in young animals therefore controls a neural activity state transition and is required for improved associative learning, providing insight into the maturation of circuits and behavior.
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Affiliation(s)
- Sarah G Leinwand
- Department of Molecular and Cell Biology and Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA 94720, USA.
| | - Kristin Scott
- Department of Molecular and Cell Biology and Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA 94720, USA.
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30
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Axonal chemokine-like Orion induces astrocyte infiltration and engulfment during mushroom body neuronal remodeling. Nat Commun 2021; 12:1849. [PMID: 33758182 PMCID: PMC7988174 DOI: 10.1038/s41467-021-22054-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Accepted: 02/25/2021] [Indexed: 11/13/2022] Open
Abstract
The remodeling of neurons is a conserved fundamental mechanism underlying nervous system maturation and function. Astrocytes can clear neuronal debris and they have an active role in neuronal remodeling. Developmental axon pruning of Drosophila memory center neurons occurs via a degenerative process mediated by infiltrating astrocytes. However, how astrocytes are recruited to the axons during brain development is unclear. Using an unbiased screen, we identify the gene requirement of orion, encoding for a chemokine-like protein, in the developing mushroom bodies. Functional analysis shows that Orion is necessary for both axonal pruning and removal of axonal debris. Orion performs its functions extracellularly and bears some features common to chemokines, a family of chemoattractant cytokines. We propose that Orion is a neuronal signal that elicits astrocyte infiltration and astrocyte-driven axonal engulfment required during neuronal remodeling in the Drosophila developing brain. Astrocytes can engulf axonal debris in the developing brain. However, the mechanisms regulating astrocyte recruitment to the proper axons is unclear. Here, the authors identify Orion as a signal for astrocyte infiltration and engulfment to the mushroom bodies in the Drosophila developing brain.
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31
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Yaniv SP, Meltzer H, Alyagor I, Schuldiner O. Developmental axon regrowth and primary neuron sprouting utilize distinct actin elongation factors. J Cell Biol 2021; 219:151569. [PMID: 32191286 PMCID: PMC7199854 DOI: 10.1083/jcb.201903181] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2019] [Revised: 11/06/2019] [Accepted: 02/14/2020] [Indexed: 01/23/2023] Open
Abstract
Intrinsic neurite growth potential is a key determinant of neuronal regeneration efficiency following injury. The stereotypical remodeling of Drosophila γ-neurons includes developmental regrowth of pruned axons to form adult specific connections, thereby offering a unique system to uncover growth potential regulators. Motivated by the dynamic expression in remodeling γ-neurons, we focus here on the role of actin elongation factors as potential regulators of developmental axon regrowth. We found that regrowth in vivo requires the actin elongation factors Ena and profilin, but not the formins that are expressed in γ-neurons. In contrast, primary γ-neuron sprouting in vitro requires profilin and the formin DAAM, but not Ena. Furthermore, we demonstrate that DAAM can compensate for the loss of Ena in vivo. Similarly, DAAM mutants express invariably high levels of Ena in vitro. Thus, we show that different linear actin elongation factors function in distinct contexts even within the same cell type and that they can partially compensate for each other.
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Affiliation(s)
- Shiri P Yaniv
- Department of Molecular Cell Biology, Weizmann Institute of Sciences, Rehovot, Israel
| | - Hagar Meltzer
- Department of Molecular Cell Biology, Weizmann Institute of Sciences, Rehovot, Israel
| | - Idan Alyagor
- Department of Molecular Cell Biology, Weizmann Institute of Sciences, Rehovot, Israel
| | - Oren Schuldiner
- Department of Molecular Cell Biology, Weizmann Institute of Sciences, Rehovot, Israel
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32
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Xie Q, Brbic M, Horns F, Kolluru SS, Jones RC, Li J, Reddy AR, Xie A, Kohani S, Li Z, McLaughlin CN, Li T, Xu C, Vacek D, Luginbuhl DJ, Leskovec J, Quake SR, Luo L, Li H. Temporal evolution of single-cell transcriptomes of Drosophila olfactory projection neurons. eLife 2021; 10:e63450. [PMID: 33427646 PMCID: PMC7870145 DOI: 10.7554/elife.63450] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Accepted: 01/05/2021] [Indexed: 12/18/2022] Open
Abstract
Neurons undergo substantial morphological and functional changes during development to form precise synaptic connections and acquire specific physiological properties. What are the underlying transcriptomic bases? Here, we obtained the single-cell transcriptomes of Drosophila olfactory projection neurons (PNs) at four developmental stages. We decoded the identity of 21 transcriptomic clusters corresponding to 20 PN types and developed methods to match transcriptomic clusters representing the same PN type across development. We discovered that PN transcriptomes reflect unique biological processes unfolding at each stage-neurite growth and pruning during metamorphosis at an early pupal stage; peaked transcriptomic diversity during olfactory circuit assembly at mid-pupal stages; and neuronal signaling in adults. At early developmental stages, PN types with adjacent birth order share similar transcriptomes. Together, our work reveals principles of cellular diversity during brain development and provides a resource for future studies of neural development in PNs and other neuronal types.
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Affiliation(s)
- Qijing Xie
- Department of Biology, Howard Hughes Medical Institute, Stanford UniversityStanfordUnited States
- Neurosciences Graduate Program, Stanford UniversityStanfordUnited States
| | - Maria Brbic
- Department of Computer Science, Stanford UniversityStanfordUnited States
| | - Felix Horns
- Department of Bioengineering, Stanford UniversityStanfordUnited States
- Biophysics Graduate Program, Stanford UniversityStanfordUnited States
| | | | - Robert C Jones
- Department of Bioengineering, Stanford UniversityStanfordUnited States
| | - Jiefu Li
- Department of Biology, Howard Hughes Medical Institute, Stanford UniversityStanfordUnited States
| | - Anay R Reddy
- Department of Biology, Howard Hughes Medical Institute, Stanford UniversityStanfordUnited States
| | - Anthony Xie
- Department of Biology, Howard Hughes Medical Institute, Stanford UniversityStanfordUnited States
| | - Sayeh Kohani
- Department of Biology, Howard Hughes Medical Institute, Stanford UniversityStanfordUnited States
| | - Zhuoran Li
- Department of Biology, Howard Hughes Medical Institute, Stanford UniversityStanfordUnited States
| | - Colleen N McLaughlin
- Department of Biology, Howard Hughes Medical Institute, Stanford UniversityStanfordUnited States
| | - Tongchao Li
- Department of Biology, Howard Hughes Medical Institute, Stanford UniversityStanfordUnited States
| | - Chuanyun Xu
- Department of Biology, Howard Hughes Medical Institute, Stanford UniversityStanfordUnited States
| | - David Vacek
- Department of Biology, Howard Hughes Medical Institute, Stanford UniversityStanfordUnited States
| | - David J Luginbuhl
- Department of Biology, Howard Hughes Medical Institute, Stanford UniversityStanfordUnited States
| | - Jure Leskovec
- Department of Computer Science, Stanford UniversityStanfordUnited States
| | - Stephen R Quake
- Department of Bioengineering, Stanford UniversityStanfordUnited States
- Department of Applied Physics, Stanford UniversityStanfordUnited States
- Chan Zuckerberg BiohubStanfordUnited States
| | - Liqun Luo
- Department of Biology, Howard Hughes Medical Institute, Stanford UniversityStanfordUnited States
| | - Hongjie Li
- Department of Biology, Howard Hughes Medical Institute, Stanford UniversityStanfordUnited States
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33
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Mulvey B, Lagunas T, Dougherty JD. Massively Parallel Reporter Assays: Defining Functional Psychiatric Genetic Variants Across Biological Contexts. Biol Psychiatry 2021; 89:76-89. [PMID: 32843144 PMCID: PMC7938388 DOI: 10.1016/j.biopsych.2020.06.011] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Revised: 06/09/2020] [Accepted: 06/10/2020] [Indexed: 12/18/2022]
Abstract
Neuropsychiatric phenotypes have long been known to be influenced by heritable risk factors, directly confirmed by the past decade of genetic studies that have revealed specific genetic variants enriched in disease cohorts. However, the initial hope that a small set of genes would be responsible for a given disorder proved false. The more complex reality is that a given disorder may be influenced by myriad small-effect noncoding variants and/or by rare but severe coding variants, many de novo. Noncoding genomic sequences-for which molecular functions cannot usually be inferred-harbor a large portion of these variants, creating a substantial barrier to understanding higher-order molecular and biological systems of disease. Fortunately, novel genetic technologies-scalable oligonucleotide synthesis, RNA sequencing, and CRISPR (clustered regularly interspaced short palindromic repeats)-have opened novel avenues to experimentally identify biologically significant variants en masse. Massively parallel reporter assays (MPRAs) are an especially versatile technique resulting from such innovations. MPRAs are powerful molecular genetics tools that can be used to screen thousands of untranscribed or untranslated sequences and their variants for functional effects in a single experiment. This approach, though underutilized in psychiatric genetics, has several useful features for the field. We review methods for assaying putatively functional genetic variants and regions, emphasizing MPRAs and the opportunities they hold for dissection of psychiatric polygenicity. We discuss literature applying functional assays in neurogenetics, highlighting strengths, caveats, and design considerations-especially regarding disease-relevant variables (cell type, neurodevelopment, and sex), and we ultimately propose applications of MPRA to both computational and experimental neurogenetics of polygenic disease risk.
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Affiliation(s)
- Bernard Mulvey
- Division of Biology and Biomedical Sciences, Washington University School of Medicine in St. Louis, St. Louis, Missouri; Department of Genetics, Washington University School of Medicine in St. Louis, St. Louis, Missouri; Department of Psychiatry, Washington University School of Medicine in St. Louis, St. Louis, Missouri
| | - Tomás Lagunas
- Division of Biology and Biomedical Sciences, Washington University School of Medicine in St. Louis, St. Louis, Missouri; Department of Genetics, Washington University School of Medicine in St. Louis, St. Louis, Missouri; Department of Psychiatry, Washington University School of Medicine in St. Louis, St. Louis, Missouri
| | - Joseph D Dougherty
- Department of Genetics, Washington University School of Medicine in St. Louis, St. Louis, Missouri; Department of Psychiatry, Washington University School of Medicine in St. Louis, St. Louis, Missouri.
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Eschment M, Franz HR, Güllü N, Hölscher LG, Huh KE, Widmann A. Insulin signaling represents a gating mechanism between different memory phases in Drosophila larvae. PLoS Genet 2020; 16:e1009064. [PMID: 33104728 PMCID: PMC7644093 DOI: 10.1371/journal.pgen.1009064] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Revised: 11/05/2020] [Accepted: 08/19/2020] [Indexed: 12/18/2022] Open
Abstract
The ability to learn new skills and to store them as memory entities is one of the most impressive features of higher evolved organisms. However, not all memories are created equal; some are short-lived forms, and some are longer lasting. Formation of the latter is energetically costly and by the reason of restricted availability of food or fluctuations in energy expanses, efficient metabolic homeostasis modulating different needs like survival, growth, reproduction, or investment in longer lasting memories is crucial. Whilst equipped with cellular and molecular pre-requisites for formation of a protein synthesis dependent long-term memory (LTM), its existence in the larval stage of Drosophila remains elusive. Considering it from the viewpoint that larval brain structures are completely rebuilt during metamorphosis, and that this process depends completely on accumulated energy stores formed during the larval stage, investing in LTM represents an unnecessary expenditure. However, as an alternative, Drosophila larvae are equipped with the capacity to form a protein synthesis independent so-called larval anaesthesia resistant memory (lARM), which is consolidated in terms of being insensitive to cold-shock treatments. Motivated by the fact that LTM formation causes an increase in energy uptake in Drosophila adults, we tested the idea of whether an energy surplus can induce the formation of LTM in the larval stage. Suprisingly, increasing the metabolic state by feeding Drosophila larvae the disaccharide sucrose directly before aversive olfactory conditioning led to the formation of a protein synthesis dependent longer lasting memory. Moreover, formation of this memory component is accompanied by the suppression of lARM. We ascertained that insulin receptors (InRs) expressed in the mushroom body Kenyon cells suppresses the formation of lARM and induces the formation of a protein synthesis dependent longer lasting memory in Drosophila larvae. Given the numerical simplicity of the larval nervous system this work offers a unique prospect to study the impact of insulin signaling on the formation of protein synthesis dependent memories on a molecular level.
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Affiliation(s)
- Melanie Eschment
- Department of Biology, University of Konstanz, Konstanz, Germany
| | - Hanna R. Franz
- Department of Molecular Neurobiology of Behavior, University of Göttingen, Göttingen, Germany
| | - Nazlı Güllü
- Department of Biology, University of Konstanz, Konstanz, Germany
| | - Luis G. Hölscher
- Department of Molecular Neurobiology of Behavior, University of Göttingen, Göttingen, Germany
| | - Ko-Eun Huh
- Department of Molecular Neurobiology of Behavior, University of Göttingen, Göttingen, Germany
| | - Annekathrin Widmann
- Department of Biology, University of Konstanz, Konstanz, Germany
- Department of Molecular Neurobiology of Behavior, University of Göttingen, Göttingen, Germany
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35
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Hasan G, Sharma A. Regulation of neuronal physiology by Ca2+ release through the IP3R. CURRENT OPINION IN PHYSIOLOGY 2020. [DOI: 10.1016/j.cophys.2020.06.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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36
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Kim YS, Choi J, Yoon BE. Neuron-Glia Interactions in Neurodevelopmental Disorders. Cells 2020; 9:cells9102176. [PMID: 32992620 PMCID: PMC7601502 DOI: 10.3390/cells9102176] [Citation(s) in RCA: 68] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2020] [Revised: 09/24/2020] [Accepted: 09/24/2020] [Indexed: 12/12/2022] Open
Abstract
Recent studies have revealed synaptic dysfunction to be a hallmark of various psychiatric diseases, and that glial cells participate in synapse formation, development, and plasticity. Glial cells contribute to neuroinflammation and synaptic homeostasis, the latter being essential for maintaining the physiological function of the central nervous system (CNS). In particular, glial cells undergo gliotransmission and regulate neuronal activity in tripartite synapses via ion channels (gap junction hemichannel, volume regulated anion channel, and bestrophin-1), receptors (for neurotransmitters and cytokines), or transporters (GLT-1, GLAST, and GATs) that are expressed on glial cell membranes. In this review, we propose that dysfunction in neuron-glia interactions may contribute to the pathogenesis of neurodevelopmental disorders. Understanding the mechanisms of neuron-glia interaction for synapse formation and maturation will contribute to the development of novel therapeutic targets of neurodevelopmental disorders.
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Affiliation(s)
- Yoo Sung Kim
- Department of Molecular Biology, Dankook University, Cheonan 31116, Korea; (Y.S.K.); (J.C.)
| | - Juwon Choi
- Department of Molecular Biology, Dankook University, Cheonan 31116, Korea; (Y.S.K.); (J.C.)
| | - Bo-Eun Yoon
- Department of Molecular Biology, Dankook University, Cheonan 31116, Korea; (Y.S.K.); (J.C.)
- Department of Nanobiomedical science, Dankook University, Cheonan 31116, Korea
- Correspondence: ; Tel.: +82-41-529-6085
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37
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Aponte-Santiago NA, Ormerod KG, Akbergenova Y, Littleton JT. Synaptic Plasticity Induced by Differential Manipulation of Tonic and Phasic Motoneurons in Drosophila. J Neurosci 2020; 40:6270-6288. [PMID: 32631939 PMCID: PMC7424871 DOI: 10.1523/jneurosci.0925-20.2020] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Revised: 06/22/2020] [Accepted: 06/28/2020] [Indexed: 12/12/2022] Open
Abstract
Structural and functional plasticity induced by neuronal competition is a common feature of developing nervous systems. However, the rules governing how postsynaptic cells differentiate between presynaptic inputs are unclear. In this study, we characterized synaptic interactions following manipulations of tonic Ib or phasic Is glutamatergic motoneurons that coinnervate postsynaptic muscles of male or female Drosophila melanogaster larvae. After identifying drivers for each neuronal subtype, we performed ablation or genetic manipulations to alter neuronal activity and examined the effects on synaptic innervation and function at neuromuscular junctions. Ablation of either Ib or Is resulted in decreased muscle response, with some functional compensation occurring in the Ib input when Is was missing. In contrast, the Is terminal failed to show functional or structural changes following loss of the coinnervating Ib input. Decreasing the activity of the Ib or Is neuron with tetanus toxin light chain resulted in structural changes in muscle innervation. Decreased Ib activity resulted in reduced active zone (AZ) number and decreased postsynaptic subsynaptic reticulum volume, with the emergence of filopodial-like protrusions from synaptic boutons of the Ib input. Decreased Is activity did not induce structural changes at its own synapses, but the coinnervating Ib motoneuron increased the number of synaptic boutons and AZs it formed. These findings indicate that tonic Ib and phasic Is motoneurons respond independently to changes in activity, with either functional or structural alterations in the Ib neuron occurring following ablation or reduced activity of the coinnervating Is input, respectively.SIGNIFICANCE STATEMENT Both invertebrate and vertebrate nervous systems display synaptic plasticity in response to behavioral experiences, indicating that underlying mechanisms emerged early in evolution. How specific neuronal classes innervating the same postsynaptic target display distinct types of plasticity is unclear. Here, we examined whether Drosophila tonic Ib and phasic Is motoneurons display competitive or cooperative interactions during innervation of the same muscle, or compensatory changes when the output of one motoneuron is altered. We established a system to differentially manipulate the motoneurons and examined the effects of cell type-specific changes to one of the inputs. Our findings indicate Ib and Is motoneurons respond differently to activity mismatch or loss of the coinnervating input, with the Ib subclass responding robustly compared with Is motoneurons.
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Affiliation(s)
- Nicole A Aponte-Santiago
- The Picower Institute for Learning and Memory, Department of Biology and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
| | - Kiel G Ormerod
- The Picower Institute for Learning and Memory, Department of Biology and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
| | - Yulia Akbergenova
- The Picower Institute for Learning and Memory, Department of Biology and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
| | - J Troy Littleton
- The Picower Institute for Learning and Memory, Department of Biology and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
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38
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Rossi AM, Desplan C. Extrinsic activin signaling cooperates with an intrinsic temporal program to increase mushroom body neuronal diversity. eLife 2020; 9:58880. [PMID: 32628110 PMCID: PMC7365662 DOI: 10.7554/elife.58880] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Accepted: 07/03/2020] [Indexed: 12/16/2022] Open
Abstract
Temporal patterning of neural progenitors leads to the sequential production of diverse neurons. To understand how extrinsic cues influence intrinsic temporal programs, we studied Drosophila mushroom body progenitors (neuroblasts) that sequentially produce only three neuronal types: γ, then α’β’, followed by αβ. Opposing gradients of two RNA-binding proteins Imp and Syp comprise the intrinsic temporal program. Extrinsic activin signaling regulates the production of α’β’ neurons but whether it affects the intrinsic temporal program was not known. We show that the activin ligand Myoglianin from glia regulates the temporal factor Imp in mushroom body neuroblasts. Neuroblasts missing the activin receptor Baboon have a delayed intrinsic program as Imp is higher than normal during the α’β’ temporal window, causing the loss of α’β’ neurons, a decrease in αβ neurons, and a likely increase in γ neurons, without affecting the overall number of neurons produced. Our results illustrate that an extrinsic cue modifies an intrinsic temporal program to increase neuronal diversity.
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Affiliation(s)
- Anthony M Rossi
- Department of Biology, New York University, New York, United States
| | - Claude Desplan
- Department of Biology, New York University, New York, United States
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39
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Kozlov A, Koch R, Nagoshi E. Nitric oxide mediates neuro-glial interaction that shapes Drosophila circadian behavior. PLoS Genet 2020; 16:e1008312. [PMID: 32598344 PMCID: PMC7367490 DOI: 10.1371/journal.pgen.1008312] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Revised: 07/17/2020] [Accepted: 06/05/2020] [Indexed: 11/25/2022] Open
Abstract
Drosophila circadian behavior relies on the network of heterogeneous groups of clock neurons. Short- and long-range signaling within the pacemaker circuit coordinates molecular and neural rhythms of clock neurons to generate coherent behavioral output. The neurochemistry of circadian behavior is complex and remains incompletely understood. Here we demonstrate that the gaseous messenger nitric oxide (NO) is a signaling molecule linking circadian pacemaker to rhythmic locomotor activity. We show that mutants lacking nitric oxide synthase (NOS) have behavioral arrhythmia in constant darkness, although molecular clocks in the main pacemaker neurons are unaffected. Behavioral phenotypes of mutants are due in part to the malformation of neurites of the main pacemaker neurons, s-LNvs. Using cell-type selective and stage-specific gain- and loss-of-function of NOS, we also demonstrate that NO secreted from diverse cellular clusters affect behavioral rhythms. Furthermore, we identify the perineurial glia, one of the two glial subtypes that form the blood-brain barrier, as the major source of NO that regulates circadian locomotor output. These results reveal for the first time the critical role of NO signaling in the Drosophila circadian system and highlight the importance of neuro-glial interaction in the neural circuit output. Circadian rhythms are daily cycles of physiological and behavioral processes found in most organisms on our planet from cyanobacteria to humans. Circadian rhythms allow organisms to anticipate routine daily and annual changes of environmental conditions and efficiently adapt to them. Fruit fly Drosophila melanogaster is an excellent model to study this phenomenon, as its versatile toolkit enables the study of genetic, molecular and neuronal mechanisms of rhythm generation. Here we report for the first time that gasotransmitter nitric oxide (NO) has a broad, multi-faceted impact on Drosophila circadian rhythms, which takes place both during the development and the adulthood. We also show that one of the important contributors of NO to circadian rhythms are glial cells that form the blood-brain barrier. The second finding highlights that circadian rhythms of higher organisms are not simply controlled by the small number of pacemaker neurons but are generated by the system that consists of many different players, including glia.
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Affiliation(s)
- Anatoly Kozlov
- Department of Genetics and Evolution, Sciences III, University of Geneva, Quai Ernest-Ansermet, Switzerland
| | - Rafael Koch
- Department of Genetics and Evolution, Sciences III, University of Geneva, Quai Ernest-Ansermet, Switzerland
| | - Emi Nagoshi
- Department of Genetics and Evolution, Sciences III, University of Geneva, Quai Ernest-Ansermet, Switzerland
- * E-mail:
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40
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Sudarsanam S, Yaniv S, Meltzer H, Schuldiner O. Cofilin regulates axon growth and branching of Drosophila γ-neurons. J Cell Sci 2020; 133:jcs232595. [PMID: 32152181 PMCID: PMC7197873 DOI: 10.1242/jcs.232595] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2019] [Accepted: 02/18/2020] [Indexed: 12/29/2022] Open
Abstract
The mechanisms that control intrinsic axon growth potential, and thus axon regeneration following injury, are not well understood. Developmental axon regrowth of Drosophila mushroom body γ-neurons during neuronal remodeling offers a unique opportunity to study the molecular mechanisms controlling intrinsic growth potential. Motivated by the recently uncovered developmental expression atlas of γ-neurons, we here focus on the role of the actin-severing protein cofilin during axon regrowth. We show that Twinstar (Tsr), the fly cofilin, is a crucial regulator of both axon growth and branching during developmental remodeling of γ-neurons. tsr mutant axons demonstrate growth defects both in vivo and in vitro, and also exhibit actin-rich filopodial-like structures at failed branch points in vivo Our data is inconsistent with Tsr being important for increasing G-actin availability. Furthermore, analysis of microtubule localization suggests that Tsr is required for microtubule infiltration into the axon tips and branch points. Taken together, we show that Tsr promotes axon growth and branching, likely by clearing F-actin to facilitate protrusion of microtubules.
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Affiliation(s)
- Sriram Sudarsanam
- Department of Molecular Cell Biology, Weizmann Institute of Sciences, Rehovot 7610001, Israel
| | - Shiri Yaniv
- Department of Molecular Cell Biology, Weizmann Institute of Sciences, Rehovot 7610001, Israel
| | - Hagar Meltzer
- Department of Molecular Cell Biology, Weizmann Institute of Sciences, Rehovot 7610001, Israel
| | - Oren Schuldiner
- Department of Molecular Cell Biology, Weizmann Institute of Sciences, Rehovot 7610001, Israel
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41
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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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42
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Marchetti G, Tavosanis G. Modulators of hormonal response regulate temporal fate specification in the Drosophila brain. PLoS Genet 2019; 15:e1008491. [PMID: 31809495 PMCID: PMC6919624 DOI: 10.1371/journal.pgen.1008491] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2019] [Revised: 12/18/2019] [Accepted: 10/24/2019] [Indexed: 12/03/2022] Open
Abstract
Neuronal diversity is at the core of the complex processing operated by the nervous system supporting fundamental functions such as sensory perception, motor control or memory formation. A small number of progenitors guarantee the production of this neuronal diversity, with each progenitor giving origin to different neuronal types over time. How a progenitor sequentially produces neurons of different fates and the impact of extrinsic signals conveying information about developmental progress or environmental conditions on this process represent key, but elusive questions. Each of the four progenitors of the Drosophila mushroom body (MB) sequentially gives rise to the MB neuron subtypes. The temporal fate determination pattern of MB neurons can be influenced by extrinsic cues, conveyed by the steroid hormone ecdysone. Here, we show that the activation of Transforming Growth Factor-β (TGF-β) signalling via glial-derived Myoglianin regulates the fate transition between the early-born α’β’ and the pioneer αβ MB neurons by promoting the expression of the ecdysone receptor B1 isoform (EcR-B1). While TGF-β signalling is required in MB neuronal progenitors to promote the expression of EcR-B1, ecdysone signalling acts postmitotically to consolidate theα’β’ MB fate. Indeed, we propose that if these signalling cascades are impaired α’β’ neurons lose their fate and convert to pioneer αβ. Conversely, an intrinsic signal conducted by the zinc finger transcription factor Krüppel-homolog 1 (Kr-h1) antagonises TGF-β signalling and acts as negative regulator of the response mediated by ecdysone in promoting α’β’ MB neuron fate consolidation. Taken together, the consolidation of α’β’ MB neuron fate requires the response of progenitors to local signalling to enable postmitotic neurons to sense a systemic signal. Throughout the development of the central nervous system (CNS), a vast number of neuronal types are produced with striking precision. The unique identity of each neuronal cell type and the great cellular complexity in the CNS are established by intricate gene regulatory networks. Disruption of these identity programs leads to neurodevelopmental disorders and defects in cognition. Here, we report an important regulatory mechanism involved in consolidating neuronal fate. We show that during brain development local signalling, derived from interactions between glial cells and neuronal progenitors, is required to promote the expression of a hormone receptor in immature neurons. The perception of a systemic hormonal cue in those postmitotic neurons is fundamental for the consolidation of their neuronal fate. In this context, we additionally uncover an intrinsic regulatory mechanism that coordinates the hormone response to maintain the final neuronal fate.
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Affiliation(s)
- Giovanni Marchetti
- Dynamics of neuronal circuits, German Center for Neurodegenerative Diseases (DZNE), Germany
- * E-mail: (GM); (GT)
| | - Gaia Tavosanis
- Dynamics of neuronal circuits, German Center for Neurodegenerative Diseases (DZNE), Germany
- LIMES-Institute, University of Bonn, Germany
- * E-mail: (GM); (GT)
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43
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Liu LY, Long X, Yang CP, Miyares RL, Sugino K, Singer RH, Lee T. Mamo decodes hierarchical temporal gradients into terminal neuronal fate. eLife 2019; 8:e48056. [PMID: 31545163 PMCID: PMC6764822 DOI: 10.7554/elife.48056] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2019] [Accepted: 09/20/2019] [Indexed: 12/20/2022] Open
Abstract
Temporal patterning is a seminal method of expanding neuronal diversity. Here we unravel a mechanism decoding neural stem cell temporal gene expression and transforming it into discrete neuronal fates. This mechanism is characterized by hierarchical gene expression. First, Drosophila neuroblasts express opposing temporal gradients of RNA-binding proteins, Imp and Syp. These proteins promote or inhibit chinmo translation, yielding a descending neuronal gradient. Together, first and second-layer temporal factors define a temporal expression window of BTB-zinc finger nuclear protein, Mamo. The precise temporal induction of Mamo is achieved via both transcriptional and post-transcriptional regulation. Finally, Mamo is essential for the temporally defined, terminal identity of α'/β' mushroom body neurons and identity maintenance. We describe a straightforward paradigm of temporal fate specification where diverse neuronal fates are defined via integrating multiple layers of gene regulation. The neurodevelopmental roles of orthologous/related mammalian genes suggest a fundamental conservation of this mechanism in brain development.
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Affiliation(s)
- Ling-Yu Liu
- Howard Hughes Medical Institute, Janelia Research CampusAshburnUnited States
| | - Xi Long
- Howard Hughes Medical Institute, Janelia Research CampusAshburnUnited States
| | - Ching-Po Yang
- Howard Hughes Medical Institute, Janelia Research CampusAshburnUnited States
| | - Rosa L Miyares
- Howard Hughes Medical Institute, Janelia Research CampusAshburnUnited States
| | - Ken Sugino
- Howard Hughes Medical Institute, Janelia Research CampusAshburnUnited States
| | - Robert H Singer
- Howard Hughes Medical Institute, Janelia Research CampusAshburnUnited States
- Department of Anatomy and Structural Biology, Gruss Lipper Biophotonics CenterAlbert Einstein College of MedicineNew YorkUnited States
- Dominick P Purpura Department of Neuroscience, Gruss Lipper Biophotonics CenterAlbert Einstein College of MedicineNew YorkUnited States
| | - Tzumin Lee
- Howard Hughes Medical Institute, Janelia Research CampusAshburnUnited States
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44
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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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45
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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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