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Yost RT, Scott AM, Kurbaj JM, Walshe-Roussel B, Dukas R, Simon AF. Recovery from social isolation requires dopamine in males, but not the autism-related gene nlg3 in either sex. ROYAL SOCIETY OPEN SCIENCE 2024; 11:240604. [PMID: 39086833 PMCID: PMC11288677 DOI: 10.1098/rsos.240604] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/12/2023] [Revised: 05/31/2024] [Accepted: 05/31/2024] [Indexed: 08/02/2024]
Abstract
Social isolation causes profound changes in social behaviour in a variety of species. However, the genetic and molecular mechanisms modulating behavioural responses to social isolation and social recovery remain to be elucidated. Here, we quantified the behavioural response of vinegar flies to social isolation using two distinct protocols (social space preference and sociability, the spontaneous tendencies to form groups). We found that social isolation increased social space and reduced sociability. These effects of social isolation were reversible and could be reduced after 3 days of group housing. Flies with a loss of function of neuroligin3 (orthologue of autism-related neuroligin genes) with known increased social space in a socially enriched environment were still able to recover from social isolation. We also show that dopamine (DA) is needed for a response to social isolation and recovery in males but not in females. Furthermore, only in males, DA levels are reduced after isolation and are not recovered after group housing. Finally, in socially enriched flies mutant for neuroligin3, DA levels are reduced in males, but not in females. We propose a model to explain how DA and neuroligin3 are involved in the behavioural response to social isolation and its recovery in a dynamic and sex-specific manner.
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Affiliation(s)
- Ryley T. Yost
- Department of Biology, Western University, London, Ontario, Canada
| | | | - Judy M. Kurbaj
- Department of Biology, Western University, London, Ontario, Canada
| | | | - Reuven Dukas
- Department of Psychology, Neuroscience and Behaviour, Animal Behaviour Group, McMaster University, Hamilton, Ontario, Canada
| | - Anne F. Simon
- Department of Biology, Western University, London, Ontario, Canada
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2
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von Saucken VE, Windner SE, Baylies MK. Postsynaptic BMP signaling regulates myonuclear properties in Drosophila larval muscles. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.10.588944. [PMID: 38645063 PMCID: PMC11030338 DOI: 10.1101/2024.04.10.588944] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/23/2024]
Abstract
The syncytial mammalian muscle fiber contains a heterogeneous population of (myo)nuclei. At the neuromuscular junction (NMJ), myonuclei have specialized positioning and gene expression. However, it remains unclear how myonuclei are recruited and what regulates myonuclear output at the NMJ. Here, we identify specific properties of myonuclei located near the Drosophila larval NMJ. These synaptic myonuclei have increased size in relation to their surrounding cytoplasmic domain (scaling), increased DNA content (ploidy), and increased levels of transcription factor pMad, a readout for BMP signaling activity. Our genetic manipulations show local BMP signaling affects muscle size, nuclear size, ploidy, and NMJ size and function. In support, RNA sequencing analysis reveals that pMad regulates genes involved in muscle growth, ploidy (i.e., E2f1), and neurotransmission. Our data suggest that muscle BMP signaling instructs synaptic myonuclear output that then positively shapes the NMJ synapse. This study deepens our understanding of how myonuclear heterogeneity supports local signaling demands to fine tune cellular function and NMJ activity.
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Affiliation(s)
- Victoria E. von Saucken
- Developmental Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY 10065 USA
- Weill Cornell-Rockefeller-Sloan Kettering Tri-Institutional MD-PhD Program, New York, NY 10065 USA
- Biochemistry, Cell & Developmental Biology, and Molecular Biology (BCMB) Program, Weill Cornell Graduate School of Medical Sciences, New York, NY 10065 USA
| | - Stefanie E. Windner
- Developmental Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY 10065 USA
| | - Mary K. Baylies
- Developmental Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY 10065 USA
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3
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Akiyama T, Raftery LA, Wharton KA. Bone morphogenetic protein signaling: the pathway and its regulation. Genetics 2024; 226:iyad200. [PMID: 38124338 PMCID: PMC10847725 DOI: 10.1093/genetics/iyad200] [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: 07/31/2023] [Accepted: 10/27/2023] [Indexed: 12/23/2023] Open
Abstract
In the mid-1960s, bone morphogenetic proteins (BMPs) were first identified in the extracts of bone to have the remarkable ability to induce heterotopic bone. When the Drosophila gene decapentaplegic (dpp) was first identified to share sequence similarity with mammalian BMP2/BMP4 in the late-1980s, it became clear that secreted BMP ligands can mediate processes other than bone formation. Following this discovery, collaborative efforts between Drosophila geneticists and mammalian biochemists made use of the strengths of their respective model systems to identify BMP signaling components and delineate the pathway. The ability to conduct genetic modifier screens in Drosophila with relative ease was critical in identifying the intracellular signal transducers for BMP signaling and the related transforming growth factor-beta/activin signaling pathway. Such screens also revealed a host of genes that encode other core signaling components and regulators of the pathway. In this review, we provide a historical account of this exciting time of gene discovery and discuss how the field has advanced over the past 30 years. We have learned that while the core BMP pathway is quite simple, composed of 3 components (ligand, receptor, and signal transducer), behind the versatility of this pathway lies multiple layers of regulation that ensures precise tissue-specific signaling output. We provide a sampling of these discoveries and highlight many questions that remain to be answered to fully understand the complexity of BMP signaling.
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Affiliation(s)
- Takuya Akiyama
- Department of Biology, Rich and Robin Porter Cancer Research Center, The Center for Genomic Advocacy, Indiana State University, Terre Haute, IN 47809, USA
| | - Laurel A Raftery
- School of Life Sciences, University of Nevada, 4505 S. Maryland Parkway, Las Vegas, NV 89154, USA
| | - Kristi A Wharton
- Department of Molecular Biology, Cell Biology, and Biochemistry, Carney Institute for Brain Science, Brown University, Providence, RI 02912, USA
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4
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Guangming G, Mei C, Qinfeng Y, Xiang G, Chenchen Z, Qingyuan S, Wei X, Junhua G. Neurexin and neuroligins jointly regulate synaptic degeneration at the Drosophila neuromuscular junction based on TEM studies. Front Cell Neurosci 2023; 17:1257347. [PMID: 38026694 PMCID: PMC10646337 DOI: 10.3389/fncel.2023.1257347] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Accepted: 09/12/2023] [Indexed: 12/01/2023] Open
Abstract
The Drosophila larval neuromuscular junction (NMJ) is a well-known model system and is often used to study synapse development. Here, we show synaptic degeneration at NMJ boutons, primarily based on transmission electron microscopy (TEM) studies. When degeneration starts, the subsynaptic reticulum (SSR) swells, retracts and folds inward, and the residual SSR then degenerates into a disordered, thin or linear membrane. The axon terminal begins to degenerate from the central region, and the T-bar detaches from the presynaptic membrane with clustered synaptic vesicles to accelerate large-scale degeneration. There are two degeneration modes for clear synaptic vesicles. In the first mode, synaptic vesicles without actin filaments degenerate on the membrane with ultrafine spots and collapse and disperse to form an irregular profile with dark ultrafine particles. In the second mode, clear synaptic vesicles with actin filaments degenerate into dense synaptic vesicles, form irregular dark clumps without a membrane, and collapse and disperse to form an irregular profile with dark ultrafine particles. Last, all residual membranes in NMJ boutons degenerate into a linear shape, and all the residual elements in axon terminals degenerate and eventually form a cluster of dark ultrafine particles. Swelling and retraction of the SSR occurs prior to degradation of the axon terminal, which degenerates faster and with more intensity than the SSR. NMJ bouton degeneration occurs under normal physiological conditions but is accelerated in Drosophila neurexin (dnrx) dnrx273, Drosophila neuroligin (dnlg) dnlg1 and dnlg4 mutants and dnrx83;dnlg3 and dnlg2;dnlg3 double mutants, which suggests that both neurexin and neuroligins play a vital role in preventing synaptic degeneration.
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Affiliation(s)
- Gan Guangming
- School of Medicine, Southeast University, Nanjing, Jiangsu, China
- School of Life Science and Technology, The Key Laboratory of Developmental Genes and Human Disease, Southeast University, Nanjing, Jiangsu, China
| | - Chen Mei
- School of Life Science and Technology, The Key Laboratory of Developmental Genes and Human Disease, Southeast University, Nanjing, Jiangsu, China
| | - Yu Qinfeng
- School of Medicine, Southeast University, Nanjing, Jiangsu, China
| | - Gao Xiang
- School of Medicine, Southeast University, Nanjing, Jiangsu, China
| | - Zhang Chenchen
- School of Medicine, Southeast University, Nanjing, Jiangsu, China
| | - Sheng Qingyuan
- School of Life Science and Technology, The Key Laboratory of Developmental Genes and Human Disease, Southeast University, Nanjing, Jiangsu, China
| | - Xie Wei
- School of Life Science and Technology, The Key Laboratory of Developmental Genes and Human Disease, Southeast University, Nanjing, Jiangsu, China
- The Collaborative Innovation Center for Brain Science, Southeast University, Nanjing, Jiangsu, China
| | - Geng Junhua
- School of Life Science and Technology, The Key Laboratory of Developmental Genes and Human Disease, Southeast University, Nanjing, Jiangsu, China
- Shenzhen Research Institute of Southeast University, Shenzhen, Guangdong, China
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5
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Sun Y, Li M, Geng J, Meng S, Tu R, Zhuang Y, Sun M, Rui M, Ou M, Xing G, Johnson TK, Xie W. Neuroligin 2 governs synaptic morphology and function through RACK1-cofilin signaling in Drosophila. Commun Biol 2023; 6:1056. [PMID: 37853189 PMCID: PMC10584876 DOI: 10.1038/s42003-023-05428-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Accepted: 10/06/2023] [Indexed: 10/20/2023] Open
Abstract
Neuroligins are transmembrane cell adhesion proteins well-known for their genetic links to autism spectrum disorders. Neuroligins can function by regulating the actin cytoskeleton, however the factors and mechanisms involved are still largely unknown. Here, using the Drosophila neuromuscular junction as a model, we reveal that F-Actin assembly at the Drosophila NMJ is controlled through Cofilin signaling mediated by an interaction between DNlg2 and RACK1, factors not previously known to work together. The deletion of DNlg2 displays disrupted RACK1-Cofilin signaling pathway with diminished actin cytoskeleton proteo-stasis at the terminal of the NMJ, aberrant NMJ structure, reduced synaptic transmission, and abnormal locomotion at the third-instar larval stage. Overexpression of wildtype and activated Cofilin in muscles are sufficient to rescue the morphological and physiological defects in dnlg2 mutants, while inactivated Cofilin is not. Since the DNlg2 paralog DNlg1 is known to regulate F-actin assembly mainly via a specific interaction with WAVE complex, our present work suggests that the orchestration of F-actin by Neuroligins is a diverse and complex process critical for neural connectivity.
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Affiliation(s)
- Yichen Sun
- School of Life Science and Technology, The Key Laboratory of Developmental Genes and Human Disease, Southeast University, Nanjing, 210096, China
- School of Biological Sciences, Monash University, Clayton, VIC, 3800, Australia
| | - Moyi Li
- School of Life Science and Technology, The Key Laboratory of Developmental Genes and Human Disease, Southeast University, Nanjing, 210096, China.
- Jiangsu Co-innovation Center of Neuroregeneration, Nantong University, Nantong, 226001, China.
| | - Junhua Geng
- School of Life Science and Technology, The Key Laboratory of Developmental Genes and Human Disease, Southeast University, Nanjing, 210096, China
| | - Sibie Meng
- School of Life Science and Technology, The Key Laboratory of Developmental Genes and Human Disease, Southeast University, Nanjing, 210096, China
| | - Renjun Tu
- School of Life Science and Technology, The Key Laboratory of Developmental Genes and Human Disease, Southeast University, Nanjing, 210096, China
| | - Yan Zhuang
- School of Life Science and Technology, The Key Laboratory of Developmental Genes and Human Disease, Southeast University, Nanjing, 210096, China
| | - Mingkuan Sun
- The Key Laboratory of Modern Toxicology, Ministry of Education, School of Public Health, Nanjing Medical University, Nanjing, 211166, China
| | - Menglong Rui
- School of Life Science and Technology, The Key Laboratory of Developmental Genes and Human Disease, Southeast University, Nanjing, 210096, China
| | - Mengzhu Ou
- School of Life Science and Technology, The Key Laboratory of Developmental Genes and Human Disease, Southeast University, Nanjing, 210096, China
| | - Guangling Xing
- School of Life Science and Technology, The Key Laboratory of Developmental Genes and Human Disease, Southeast University, Nanjing, 210096, China
| | - Travis K Johnson
- School of Biological Sciences, Monash University, Clayton, VIC, 3800, Australia
- Department of Biochemistry and Chemistry, and La Trobe Institute for Molecular Science, La Trobe University, Bundoora, VIC, 3086, Australia
| | - Wei Xie
- School of Life Science and Technology, The Key Laboratory of Developmental Genes and Human Disease, Southeast University, Nanjing, 210096, China.
- Jiangsu Co-innovation Center of Neuroregeneration, Nantong University, Nantong, 226001, China.
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6
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Zhou X, Gan G, Sun Y, Ou M, Geng J, Wang J, Yang X, Huang S, Jia D, Xie W, He H. GTPase-activating protein TBC1D5 coordinates with retromer to constrain synaptic growth by inhibiting BMP signaling. J Genet Genomics 2023; 50:163-177. [PMID: 36473687 DOI: 10.1016/j.jgg.2022.11.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Revised: 11/22/2022] [Accepted: 11/22/2022] [Indexed: 12/12/2022]
Abstract
Formation and plasticity of neural circuits rely on precise regulation of synaptic growth. At Drosophila neuromuscular junction (NMJ), Bone Morphogenetic Protein (BMP) signaling is critical for many aspects of synapse formation and function. The evolutionarily conserved retromer complex and its associated GTPase-activating protein TBC1D5 are critical regulators of membrane trafficking and cellular signaling. However, their functions in regulating the formation of NMJ are less understood. Here, we report that TBC1D5 is required for inhibition of synaptic growth, and loss of TBC1D5 leads to abnormal presynaptic terminal development, including excessive satellite boutons and branch formation. Ultrastructure analysis reveals that the size of synaptic vesicles and the density of subsynaptic reticulum are increased in TBC1D5 mutant boutons. Disruption of interactions of TBC1D5 with Rab7 and retromer phenocopies the loss of TBC1D5. Unexpectedly, we find that TBC1D5 is functionally linked to Rab6, in addition to Rab7, to regulate synaptic growth. Mechanistically, we show that loss of TBC1D5 leads to upregulated BMP signaling by increasing the protein level of BMP type II receptor Wishful Thinking (Wit) at NMJ. Overall, our data establish that TBC1D5 in coordination with retromer constrains synaptic growth by regulating Rab7 activity, which negatively regulates BMP signaling through inhibiting Wit level.
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Affiliation(s)
- Xiu Zhou
- State Key Laboratory of Biotherapy, Department of Neurosurgery, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, China
| | - Guangming Gan
- The Key Laboratory of Developmental Genes and Human Disease (MOE), School of Life Science and Technology, Southeast University, Nanjing, Jiangsu 210096, China; The Key Laboratory of Developmental Genes and Human Disease (MOE), School of Medicine, Southeast University, Nanjing, Jiangsu 210009, China
| | - Yichen Sun
- The Key Laboratory of Developmental Genes and Human Disease (MOE), School of Life Science and Technology, Southeast University, Nanjing, Jiangsu 210096, China
| | - Mengzhu Ou
- The Key Laboratory of Developmental Genes and Human Disease (MOE), School of Life Science and Technology, Southeast University, Nanjing, Jiangsu 210096, China
| | - Junhua Geng
- The Key Laboratory of Developmental Genes and Human Disease (MOE), School of Life Science and Technology, Southeast University, Nanjing, Jiangsu 210096, China
| | - Jing Wang
- Key Laboratory of Birth Defects and Related Diseases of Women and Children, Department of Pediatrics, West China Second University Hospital, State Key Laboratory of Biotherapy, Sichuan University, Chengdu, Sichuan 610041, China
| | - Xi Yang
- State Key Laboratory of Biotherapy, Department of Neurosurgery, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, China
| | - Shu Huang
- State Key Laboratory of Biotherapy, Department of Neurosurgery, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, China
| | - Da Jia
- Key Laboratory of Birth Defects and Related Diseases of Women and Children, Department of Pediatrics, West China Second University Hospital, State Key Laboratory of Biotherapy, Sichuan University, Chengdu, Sichuan 610041, China
| | - Wei Xie
- The Key Laboratory of Developmental Genes and Human Disease (MOE), School of Life Science and Technology, Southeast University, Nanjing, Jiangsu 210096, China.
| | - Haihuai He
- State Key Laboratory of Biotherapy, Department of Neurosurgery, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, China.
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7
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Xu W, Kong W, Gao Z, Huang E, Xie W, Wang S, Rui M. Establishment of a novel axon pruning model of Drosophila motor neuron. Biol Open 2023; 12:286282. [PMID: 36606515 PMCID: PMC9838636 DOI: 10.1242/bio.059535] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Accepted: 11/30/2022] [Indexed: 01/07/2023] Open
Abstract
Developmental neuronal pruning is a process by which neurons selectively remove excessive or unnecessary neurite without causing neuronal death. Importantly, this process is widely used for the refinement of neural circuits in both vertebrates and invertebrates, and may also contribute to the pathogenesis of neuropsychiatric disorders, such as autism and schizophrenia. In the peripheral nervous system (PNS), class IV dendritic arborization (da) sensory neurons of Drosophila, selectively remove the dendrites without losing their somas and axons, while the dendrites and axons of mushroom body (MB) γ neuron in the central nervous system (CNS) are eliminated by localized fragmentation during metamorphosis. Alternatively, dendrite pruning of ddaC neurons is usually investigated via live-cell imaging, while dissection and fixation are currently used for evaluating MB γ neuron axon pruning. Thus, an excellent model system to assess axon specific pruning directly via live-cell imaging remains elusive. Here, we report that the Drosophila motor neuron offers a unique advantage for studying axon pruning. Interestingly, we uncover that long-range projecting axon bundle from soma at ventral nerve cord (VNC), undergoes degeneration rather than retraction during metamorphosis. Strikingly, the pruning process of the motor axon bundle is straightforward to investigate via live imaging and it occurs approximately at 22 h after pupal formation (APF), when axon bundles are completely cleared. Consistently, the classical axon pruning regulators in the Drosophila MB γ neuron, including TGF-β signaling, ecdysone signaling, JNK signaling, and the ubiquitin-proteasome system are also involved in governing motor axon pruning. Finally, our findings establish an unprecedented axon pruning mode that will serve to systematically screen and identify undiscovered axon pruning regulators. This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Wanyue Xu
- School of Life Science and Technology, the Key Laboratory of Developmental Genes and Human Disease, Southeast University, 2 Sipailou Road, Nanjing 210096, China
| | - Weiyu Kong
- School of Life Science and Technology, the Key Laboratory of Developmental Genes and Human Disease, Southeast University, 2 Sipailou Road, Nanjing 210096, China
| | - Ziyang Gao
- School of Life Science and Technology, the Key Laboratory of Developmental Genes and Human Disease, Southeast University, 2 Sipailou Road, Nanjing 210096, China
| | - Erqian Huang
- School of Life Science and Technology, the Key Laboratory of Developmental Genes and Human Disease, Southeast University, 2 Sipailou Road, Nanjing 210096, China
| | - Wei Xie
- School of Life Science and Technology, the Key Laboratory of Developmental Genes and Human Disease, Southeast University, 2 Sipailou Road, Nanjing 210096, China
| | - Su Wang
- School of Life Science and Technology, the Key Laboratory of Developmental Genes and Human Disease, Southeast University, 2 Sipailou Road, Nanjing 210096, China,Authors for correspondence (; )
| | - Menglong Rui
- School of Life Science and Technology, the Key Laboratory of Developmental Genes and Human Disease, Southeast University, 2 Sipailou Road, Nanjing 210096, China,Authors for correspondence (; )
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8
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AP2 Regulates Thickveins Trafficking to Attenuate NMJ Growth Signaling in Drosophila. eNeuro 2022; 9:ENEURO.0044-22.2022. [PMID: 36180220 PMCID: PMC9581581 DOI: 10.1523/eneuro.0044-22.2022] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Revised: 09/09/2022] [Accepted: 09/23/2022] [Indexed: 12/15/2022] Open
Abstract
Compromised endocytosis in neurons leads to synapse overgrowth and altered organization of synaptic proteins. However, the molecular players and the signaling pathways which regulate the process remain poorly understood. Here, we show that σ2-adaptin, one of the subunits of the AP2-complex, genetically interacts with Mad, Medea and Dad (components of BMP signaling) to control neuromuscular junction (NMJ) growth in Drosophila Ultrastructural analysis of σ2-adaptin mutants show an accumulation of large vesicles and membranous structures akin to endosomes at the synapse. We found that mutations in σ2-adaptin lead to an accumulation of Tkv receptors at the presynaptic membrane. Interestingly, the level of small GTPase Rab11 was significantly reduced in the σ2-adaptin mutant synapses. However, expression of Rab11 does not restore the synaptic defects of σ2-adaptin mutations. We propose a model in which AP2 regulates Tkv internalization and endosomal recycling to control synaptic growth.
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9
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Fenckova M, Muha V, Mariappa D, Catinozzi M, Czajewski I, Blok LER, Ferenbach AT, Storkebaum E, Schenck A, van Aalten DMF. Intellectual disability-associated disruption of O-GlcNAc cycling impairs habituation learning in Drosophila. PLoS Genet 2022; 18:e1010159. [PMID: 35500025 PMCID: PMC9140282 DOI: 10.1371/journal.pgen.1010159] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Revised: 05/27/2022] [Accepted: 03/21/2022] [Indexed: 11/19/2022] Open
Abstract
O-GlcNAcylation is a reversible co-/post-translational modification involved in a multitude of cellular processes. The addition and removal of the O-GlcNAc modification is controlled by two conserved enzymes, O-GlcNAc transferase (OGT) and O-GlcNAc hydrolase (OGA). Mutations in OGT have recently been discovered to cause a novel Congenital Disorder of Glycosylation (OGT-CDG) that is characterized by intellectual disability. The mechanisms by which OGT-CDG mutations affect cognition remain unclear. We manipulated O-GlcNAc transferase and O-GlcNAc hydrolase activity in Drosophila and demonstrate an important role of O-GlcNAcylation in habituation learning and synaptic development at the larval neuromuscular junction. Introduction of patient-specific missense mutations into Drosophila O-GlcNAc transferase using CRISPR/Cas9 gene editing leads to deficits in locomotor function and habituation learning. The habituation deficit can be corrected by blocking O-GlcNAc hydrolysis, indicating that OGT-CDG mutations affect cognition-relevant habituation via reduced protein O-GlcNAcylation. This study establishes a critical role for O-GlcNAc cycling and disrupted O-GlcNAc transferase activity in cognitive dysfunction, and suggests that blocking O-GlcNAc hydrolysis is a potential strategy to treat OGT-CDG.
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Affiliation(s)
- Michaela Fenckova
- Division of Gene Regulation and Expression, School of Life Sciences, University of Dundee, Dundee, United Kingdom
- Department of Human Genetics, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, Netherlands
| | - Villo Muha
- Division of Gene Regulation and Expression, School of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Daniel Mariappa
- Division of Gene Regulation and Expression, School of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Marica Catinozzi
- Department of Molecular Neurobiology, Donders Institute for Brain, Cognition and Behaviour, Faculty of Science, Radboud University, Nijmegen, Netherlands
| | - Ignacy Czajewski
- Division of Gene Regulation and Expression, School of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Laura E. R. Blok
- Department of Human Genetics, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, Netherlands
| | - Andrew T. Ferenbach
- Division of Gene Regulation and Expression, School of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Erik Storkebaum
- Department of Molecular Neurobiology, Donders Institute for Brain, Cognition and Behaviour, Faculty of Science, Radboud University, Nijmegen, Netherlands
| | - Annette Schenck
- Department of Human Genetics, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, Netherlands
| | - Daan M. F. van Aalten
- Division of Gene Regulation and Expression, School of Life Sciences, University of Dundee, Dundee, United Kingdom
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10
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Welch C, Johnson E, Tupikova A, Anderson J, Tinsley B, Newman J, Widman E, Alfareh A, Davis A, Rodriguez L, Visger C, Miller-Schulze JP, Lee W, Mulligan K. Bisphenol a affects neurodevelopmental gene expression, cognitive function, and neuromuscular synaptic morphology in Drosophila melanogaster. Neurotoxicology 2022; 89:67-78. [PMID: 35041872 DOI: 10.1016/j.neuro.2022.01.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Revised: 01/05/2022] [Accepted: 01/12/2022] [Indexed: 01/02/2023]
Abstract
Bisphenol A (BPA) is an environmentally prevalent endocrine disrupting chemical that can impact human health and may be an environmental risk factor for neurodevelopmental disorders. BPA has been associated with behavioral impairment in children and a variety of neurodevelopmental phenotypes in model organisms. We used Drosophila melanogaster to explore the consequences of developmental BPA exposure on gene expression, cognitive function, and synapse development. Our transcriptome analysis indicated neurodevelopmentally relevant genes were predominantly downregulated by BPA. Among the misregulated genes were those with roles in learning, memory, and synapse development, as well as orthologs of human genes associated with neurodevelopmental and neuropsychiatric disorders. To examine how gene expression data corresponded to behavioral and cellular phenotypes, we first used a predator-response behavioral paradigm and found that BPA disrupts visual perception. Further analysis using conditioned courtship suppression showed that BPA impairs associative learning. Finally, we examined synapse morphology within the larval neuromuscular junction and found that BPA significantly increased the number of axonal branches. Given that our findings align with studies of BPA in mammalian model organisms, this data indicates that BPA impairs neurodevelopmental pathways that are functionally conserved from invertebrates to mammals. Further, because Drosophila do not possess classic estrogen receptors or estrogen, this research suggests that BPA can impact neurodevelopment by molecular mechanisms distinct from its role as an estrogen mimic.
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Affiliation(s)
- Chloe Welch
- Department of Biological Sciences, California State University, Sacramento, 6000 J Street, Sacramento, CA, 95819-6077, USA
| | - Eden Johnson
- Department of Computer Science, San José State University, 1 Washington Sq, San Jose, CA, 95192, USA
| | - Angelina Tupikova
- Department of Biological Sciences, California State University, Sacramento, 6000 J Street, Sacramento, CA, 95819-6077, USA
| | - Judith Anderson
- Department of Biological Sciences, California State University, Sacramento, 6000 J Street, Sacramento, CA, 95819-6077, USA
| | - Brendan Tinsley
- Department of Biological Sciences, California State University, Sacramento, 6000 J Street, Sacramento, CA, 95819-6077, USA
| | - Johnathan Newman
- Department of Biological Sciences, California State University, Sacramento, 6000 J Street, Sacramento, CA, 95819-6077, USA
| | - Erin Widman
- Department of Biological Sciences, California State University, Sacramento, 6000 J Street, Sacramento, CA, 95819-6077, USA
| | - Adam Alfareh
- Department of Biological Sciences, California State University, Sacramento, 6000 J Street, Sacramento, CA, 95819-6077, USA
| | - Alexandra Davis
- Department of Biological Sciences, California State University, Sacramento, 6000 J Street, Sacramento, CA, 95819-6077, USA
| | - Lucero Rodriguez
- Department of Chemistry, California State University, Sacramento, 6000 J Street, Sacramento, CA, 95819-6077, USA
| | - Clayton Visger
- Department of Biological Sciences, California State University, Sacramento, 6000 J Street, Sacramento, CA, 95819-6077, USA
| | - Justin P Miller-Schulze
- Department of Chemistry, California State University, Sacramento, 6000 J Street, Sacramento, CA, 95819-6077, USA
| | - Wendy Lee
- Department of Computer Science, San José State University, 1 Washington Sq, San Jose, CA, 95192, USA
| | - Kimberly Mulligan
- Department of Biological Sciences, California State University, Sacramento, 6000 J Street, Sacramento, CA, 95819-6077, USA.
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11
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Gunderson JT, Peppriell AE, Krout IN, Vorojeikina D, Rand MD. Neuroligin-1 Is a Mediator of Methylmercury Neuromuscular Toxicity. Toxicol Sci 2021; 184:236-251. [PMID: 34546366 DOI: 10.1093/toxsci/kfab114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Methylmercury (MeHg) is a developmental toxicant capable of eliciting neurocognitive and neuromuscular deficits in children with in utero exposure. Previous research in Drosophila melanogaster uncovered that developmental MeHg exposure simultaneously targets the developing musculature and innervating motor neuron in the embryo, along with identifying Drosophila neuroligin 1 (nlg1) as a gene associated with developmental MeHg sensitivity. Nlg1 and its transsynaptic partner neurexin 1 (Nrx1) are critical for axonal arborization and NMJ maturation. We investigated the effects of MeHg exposure on indirect flight muscle (IFM) morphogenesis, innervation, and function via flight assays and monitored the expression of NMJ-associated genes to characterize the role of Nlg1 mediating the neuromuscular toxicity of MeHg. Developmental MeHg exposure reduced the innervation of the IFMs, which corresponded with reduced flight ability. In addition, nlg1 expression was selectively reduced during early metamorphosis, whereas a subsequent increase was observed in other NMJ-associated genes, including nrx1, in late metamorphosis. Developmental MeHg exposure also resulted in persistent reduced expression of most nlg and nrx genes during the first 11 days of adulthood. Transgenic modulation of nlg1 and nrx1 revealed that developing muscle is particularly sensitive to nlg1 levels, especially during the 20-36-h window of metamorphosis with reduced nlg1 expression resulting in adult flight deficits. Muscle-specific overexpression of nlg1 partially rescued MeHg-induced deficits in eclosion and flight. We identified Nlg1 as a muscle-specific, NMJ structural component that can mediate MeHg neuromuscular toxicity resulting from early life exposure.
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Affiliation(s)
- Jakob T Gunderson
- Department of Environmental Medicine, University of Rochester School of Medicine and Dentistry, Rochester, New York 14642, USA
| | - Ashley E Peppriell
- Department of Environmental Medicine, University of Rochester School of Medicine and Dentistry, Rochester, New York 14642, USA
| | - Ian N Krout
- Department of Environmental Medicine, University of Rochester School of Medicine and Dentistry, Rochester, New York 14642, USA
| | - Daria Vorojeikina
- Department of Environmental Medicine, University of Rochester School of Medicine and Dentistry, Rochester, New York 14642, USA
| | - Matthew D Rand
- Department of Environmental Medicine, University of Rochester School of Medicine and Dentistry, Rochester, New York 14642, USA
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12
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Improved analysis method of neuromuscular junction in Drosophila larvae by transmission electron microscopy. Anat Sci Int 2021; 97:147-154. [PMID: 34661863 PMCID: PMC8732911 DOI: 10.1007/s12565-021-00635-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Accepted: 10/04/2021] [Indexed: 11/04/2022]
Abstract
The Drosophila neuromuscular junction is an excellent model for neuroscience research. However, the distribution of neuromuscular junctions is very diffuse, and it is not easy to accurately locate during ultrathin sectioning, which seriously interferes with the ultrastructural analysis under electron microscopy that only has a small field of view. Here, we reported an efficient method for acquiring the ultrastructural picture of neuromuscular junctions in Drosophila larva under electron microscopy. The procedure was as follows: first, the larval sample of body wall muscle was placed between the metal mesh and was dehydrated with alcohol and infiltrated with epoxy resin to prevent the sample from curling or bending, after it was dissected and fixed into thin slices. Second, the sample was embedded in resin into a flat sheet to facilitate the positioning of the muscles. Third, carefully and gradually remove the excess resin and the cuticle of the larvae, cut off both ends of the special body segment, and trim the excess specific muscles according to the recommended ratio of trimming muscles, which would reduce the workload exponentially. At last, the trimmed sample were prepared into serial about 1000 ultrathin sections that was about total 80 microns thickness, and 30–40 sections were gathered into a grid to stain with lead citrate and uranyl acetate. This method could also be applied to the other small and thin samples such as the Drosophila embryo, ventral nerve cord and brain.
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13
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Sharifkhodaei Z, Auld VJ. Overexpressed Gliotactin activates BMP signaling through interfering with the Tkv-Dad association. Genome 2020; 64:97-108. [PMID: 33064024 DOI: 10.1139/gen-2020-0026] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Epithelial junctions ensure cell-cell adhesion and establish permeability barriers between cells. At the corners of epithelia, the tricellular junction (TCJ) is formed by three adjacent epithelial cells and generates a functional barrier. In Drosophila, a key TCJ protein is Gliotactin (Gli) where loss of Gli disrupts barrier formation and function. Conversely, overexpressed Gli spreads away from the TCJ and triggers apoptosis, delamination, and cell migration. Thus, Gli protein levels are tightly regulated and by two mechanisms, at the protein levels by tyrosine phosphorylation and endocytosis and at the mRNA level through microRNA-184. Regulation of Gli mRNA is mediated through a Gli-BMP-miR184 feedback loop. Excessive Gli triggers BMP signaling pathway through the activation of Tkv type-I BMP receptor and Mad. Elevated level of pMad induces micrRNA-184 expression which in turn targets the Gli 3'UTR and mRNA degradation. Gli activation of Tkv is not through its ligand Dpp but rather through the inhibition of Dad, an inhibitory-Smad. Here, we show that ectopic expression of Gli interferes with Tkv-Dad association by sequestering Dad away from Tkv. The reduced inhibitory effect of Dad on Tkv results in the increased Tkv-pMad signaling activity, and this effect is continuous through larval and pupal wing formation.
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Affiliation(s)
| | - Vanessa J Auld
- Department of Zoology, University of British Columbia, Vancouver, B.C., Canada.,Department of Zoology, University of British Columbia, Vancouver, B.C., Canada
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14
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Guangming G, Junhua G, Chenchen Z, Yang M, Wei X. Neurexin and Neuroligins Maintain the Balance of Ghost and Satellite Boutons at the Drosophila Neuromuscular Junction. Front Neuroanat 2020; 14:19. [PMID: 32581727 PMCID: PMC7296126 DOI: 10.3389/fnana.2020.00019] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Accepted: 03/26/2020] [Indexed: 11/22/2022] Open
Abstract
Neurexins and neuroligins are common synaptic adhesion molecules that are associated with autism and interact with each other in the synaptic cleft. The Drosophila neuromuscular junction (NMJ) bouton is a well-known model system in neuroscience, and ghost and satellite boutons, respectively, indicate the poor development and overgrowth of the NMJ boutons. However, the Drosophila neurexin (DNrx) and Drosophila neuroligins (DNlgs) are mainly observed in type Ib boutons, indicating the ultrastructural and developmental phenotypes of the Drosophila NMJ. Here, we identified the ultrastructural and developmental features of ghost and satellite boutons by utilizing dneurexin (dnrx) and dneuroligins (dnlgs) fly mutants and other associated fly strains. Ghost boutons contain synaptic vesicles with multiple diameters but very rarely contain T-bar structures and swollen or thin subsynaptic reticulum (SSR) membranes. The muscle cell membrane is invaginated at different sites, stretches to the ghost bouton from different directions, forms several layers that enwrap the ghost bouton, and then branches into the complex SSR. Satellite boutons share a common SSR membrane and present either a typical profile in which a main bouton is encircled by small boutons or two atypical profiles in which the small boutons are grouped together or distributed in beads without a main bouton. Electron and confocal microscopy data showed that dnrx, dnlg1, dnlg2, dnlg3, and dnlg4 mutations led to ghost boutons; the overexpression of dnrx, dnlg1, dnlg2, dnlg3, and dnlg4 led to satellite boutons; and the dnlg2;dnlg3 double mutation also led to satellite boutons. These results suggested that DNrx and DNlgs jointly maintain the development and function of NMJ boutons by regulating the balance of ghost and satellite boutons in Drosophila.
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Affiliation(s)
- Gan Guangming
- School of Medicine, Southeast University, Nanjing, China.,The Key Laboratory of Developmental Genes and Human Disease, Institute of Life Sciences, Southeast University, Nanjing, China
| | - Geng Junhua
- The Key Laboratory of Developmental Genes and Human Disease, Institute of Life Sciences, Southeast University, Nanjing, China
| | - Zhang Chenchen
- School of Medicine, Southeast University, Nanjing, China.,The Key Laboratory of Developmental Genes and Human Disease, Institute of Life Sciences, Southeast University, Nanjing, China
| | - Mou Yang
- School of Medicine, Southeast University, Nanjing, China
| | - Xie Wei
- The Key Laboratory of Developmental Genes and Human Disease, Institute of Life Sciences, Southeast University, Nanjing, China.,Institute of Life Sciences, The Collaborative Innovation Center for Brain Science, Southeast University, Nanjing, China
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15
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Berke B, Le L, Keshishian H. Target-dependent retrograde signaling mediates synaptic plasticity at the Drosophila neuromuscular junction. Dev Neurobiol 2020; 79:895-912. [PMID: 31950660 DOI: 10.1002/dneu.22731] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Revised: 01/08/2020] [Accepted: 01/09/2020] [Indexed: 12/26/2022]
Abstract
Neurons that innervate multiple targets often establish synapses with target-specific strengths, and local forms of synaptic plasticity. We have examined the molecular-genetic mechanisms that allow a single Drosophila motoneuron, the ventral Common Exciter (vCE), to establish connections with target-specific properties at its various synaptic partners. By driving transgenes in a subset of vCE's targets, we found that individual target cells are able to independently control the properties of vCE's innervating branch and synapses. This is achieved by means of a trans-synaptic growth factor secreted by the target cell. At the larval neuromuscular junction, postsynaptic glutamate receptor activity stimulates the release of the BMP4/5/6 homolog Glass bottom boat (Gbb). As larvae mature and motoneuron terminals grow, Gbb activates the R-Smad transcriptional regulator phosphorylated Mad (pMad) to facilitate presynaptic development. We found that manipulations affecting glutamate receptors or Gbb within subsets of target muscles led to local effects either specific to the manipulated muscle or by a limited gradient within the presynaptic branches. While presynaptic development depends on pMad transcriptional activity within the motoneuron nucleus, we find that the Gbb growth factor may also act locally within presynaptic terminals. Local Gbb signaling and presynaptic pMad accumulation within boutons may therefore participate in a "synaptic tagging" mechanism, to influence synaptic growth and plasticity in Drosophila.
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Affiliation(s)
- Brett Berke
- Molecular, Cellular, and Developmental Biology Department, Yale University, New Haven, CT, USA
| | - Linh Le
- University of Rochester School of Medicine and Dentistry, Rochester, NY, USA
| | - Haig Keshishian
- Molecular, Cellular, and Developmental Biology Department, Yale University, New Haven, CT, USA
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16
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Bellosta P, Soldano A. Dissecting the Genetics of Autism Spectrum Disorders: A Drosophila Perspective. Front Physiol 2019; 10:987. [PMID: 31481894 PMCID: PMC6709880 DOI: 10.3389/fphys.2019.00987] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2019] [Accepted: 07/18/2019] [Indexed: 01/10/2023] Open
Abstract
Autism Spectrum Disorder (ASD) is a complex group of multi-factorial developmental disorders that leads to communication and behavioral defects. Genetic alterations have been identified in around 20% of ASD patients and the use of genetic models, such as Drosophila melanogaster, has been of paramount importance in deciphering the significance of these alterations. In fact, many of the ASD associated genes, such as FMR1, Neurexin, Neuroligins and SHANK encode for proteins that have conserved functions in neurons and during synapse development, both in humans and in the fruit fly. Drosophila is a prominent model in neuroscience due to the conserved genetic networks that control neurodevelopmental processes and to the ease of manipulating its genetics. In the present review we will describe recent advances in the field of ASD with a particular focus on the characterization of genes where the use of Drosophila has been fundamental to better understand their function.
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Affiliation(s)
- Paola Bellosta
- Laboratory of Metabolism of Cell Growth and Neuronal Survival, Department of Cellular, Computational and Integrative Biology (CIBio), University of Trento, Trento, Italy.,Department of Medicine, New York University Langone Medical Center, New York, NY, United States
| | - Alessia Soldano
- Laboratory of Translational Genomics, Department of Cellular, Computational and Integrative Biology (CIBio), University of Trento, Trento, Italy
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17
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Kumar S, Reynolds K, Ji Y, Gu R, Rai S, Zhou CJ. Impaired neurodevelopmental pathways in autism spectrum disorder: a review of signaling mechanisms and crosstalk. J Neurodev Disord 2019; 11:10. [PMID: 31202261 PMCID: PMC6571119 DOI: 10.1186/s11689-019-9268-y] [Citation(s) in RCA: 74] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Accepted: 05/02/2019] [Indexed: 12/11/2022] Open
Abstract
Background The development of an autistic brain is a highly complex process as evident from the involvement of various genetic and non-genetic factors in the etiology of the autism spectrum disorder (ASD). Despite being a multifactorial neurodevelopmental disorder, autistic patients display a few key characteristics, such as the impaired social interactions and elevated repetitive behaviors, suggesting the perturbation of specific neuronal circuits resulted from abnormal signaling pathways during brain development in ASD. A comprehensive review for autistic signaling mechanisms and interactions may provide a better understanding of ASD etiology and treatment. Main body Recent studies on genetic models and ASD patients with several different mutated genes revealed the dysregulation of several key signaling pathways, such as WNT, BMP, SHH, and retinoic acid (RA) signaling. Although no direct evidence of dysfunctional FGF or TGF-β signaling in ASD has been reported so far, a few examples of indirect evidence can be found. This review article summarizes how various genetic and non-genetic factors which have been reported contributing to ASD interact with WNT, BMP/TGF-β, SHH, FGF, and RA signaling pathways. The autism-associated gene ubiquitin-protein ligase E3A (UBE3A) has been reported to influence WNT, BMP, and RA signaling pathways, suggesting crosstalk between various signaling pathways during autistic brain development. Finally, the article comments on what further studies could be performed to gain deeper insights into the understanding of perturbed signaling pathways in the etiology of ASD. Conclusion The understanding of mechanisms behind various signaling pathways in the etiology of ASD may help to facilitate the identification of potential therapeutic targets and design of new treatment methods.
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Affiliation(s)
- Santosh Kumar
- Department of Biochemistry and Molecular Medicine, Institute for Pediatric Regenerative Medicine of Shriners Hospitals for Children, University of California at Davis School of Medicine, 2425 Stockton Blvd, Sacramento, CA, 95817, USA.
| | - Kurt Reynolds
- Department of Biochemistry and Molecular Medicine, Institute for Pediatric Regenerative Medicine of Shriners Hospitals for Children, University of California at Davis School of Medicine, 2425 Stockton Blvd, Sacramento, CA, 95817, USA
| | - Yu Ji
- Department of Biochemistry and Molecular Medicine, Institute for Pediatric Regenerative Medicine of Shriners Hospitals for Children, University of California at Davis School of Medicine, 2425 Stockton Blvd, Sacramento, CA, 95817, USA
| | - Ran Gu
- Department of Biochemistry and Molecular Medicine, Institute for Pediatric Regenerative Medicine of Shriners Hospitals for Children, University of California at Davis School of Medicine, 2425 Stockton Blvd, Sacramento, CA, 95817, USA
| | - Sunil Rai
- Department of Biochemistry and Molecular Medicine, Institute for Pediatric Regenerative Medicine of Shriners Hospitals for Children, University of California at Davis School of Medicine, 2425 Stockton Blvd, Sacramento, CA, 95817, USA
| | - Chengji J Zhou
- Department of Biochemistry and Molecular Medicine, Institute for Pediatric Regenerative Medicine of Shriners Hospitals for Children, University of California at Davis School of Medicine, 2425 Stockton Blvd, Sacramento, CA, 95817, USA.
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18
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Coll-Tané M, Krebbers A, Castells-Nobau A, Zweier C, Schenck A. Intellectual disability and autism spectrum disorders 'on the fly': insights from Drosophila. Dis Model Mech 2019; 12:dmm039180. [PMID: 31088981 PMCID: PMC6550041 DOI: 10.1242/dmm.039180] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Intellectual disability (ID) and autism spectrum disorders (ASD) are frequently co-occurring neurodevelopmental disorders and affect 2-3% of the population. Rapid advances in exome and genome sequencing have increased the number of known implicated genes by threefold, to more than a thousand. The main challenges in the field are now to understand the various pathomechanisms associated with this bewildering number of genetic disorders, to identify new genes and to establish causality of variants in still-undiagnosed cases, and to work towards causal treatment options that so far are available only for a few metabolic conditions. To meet these challenges, the research community needs highly efficient model systems. With an increasing number of relevant assays and rapidly developing novel methodologies, the fruit fly Drosophila melanogaster is ideally positioned to change gear in ID and ASD research. The aim of this Review is to summarize some of the exciting work that already has drawn attention to Drosophila as a model for these disorders. We highlight well-established ID- and ASD-relevant fly phenotypes at the (sub)cellular, brain and behavioral levels, and discuss strategies of how this extraordinarily efficient and versatile model can contribute to 'next generation' medical genomics and to a better understanding of these disorders.
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Affiliation(s)
- Mireia Coll-Tané
- Department of Human Genetics, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
| | - Alina Krebbers
- Department of Human Genetics, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
| | - Anna Castells-Nobau
- Department of Human Genetics, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
| | - Christiane Zweier
- Institute of Human Genetics, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91054 Erlangen, Germany
| | - Annette Schenck
- Department of Human Genetics, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
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19
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DePew AT, Aimino MA, Mosca TJ. The Tenets of Teneurin: Conserved Mechanisms Regulate Diverse Developmental Processes in the Drosophila Nervous System. Front Neurosci 2019; 13:27. [PMID: 30760977 PMCID: PMC6363694 DOI: 10.3389/fnins.2019.00027] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Accepted: 01/11/2019] [Indexed: 01/26/2023] Open
Abstract
To successfully integrate a neuron into a circuit, a myriad of developmental events must occur correctly and in the correct order. Neurons must be born and grow out toward a destination, responding to guidance cues to direct their path. Once arrived, each neuron must segregate to the correct sub-region before sorting through a milieu of incorrect partners to identify the correct partner with which they can connect. Finally, the neuron must make a synaptic connection with their correct partner; a connection that needs to be broadly maintained throughout the life of the animal while remaining responsive to modes of plasticity and pruning. Though many intricate molecular mechanisms have been discovered to regulate each step, recent work showed that a single family of proteins, the Teneurins, regulates a host of these developmental steps in Drosophila – an example of biological adaptive reuse. Teneurins first influence axon guidance during early development. Once neurons arrive in their target regions, Teneurins enable partner matching and synapse formation in both the central and peripheral nervous systems. Despite these diverse processes and systems, the Teneurins use conserved mechanisms to achieve these goals, as defined by three tenets: (1) transsynaptic interactions with each other, (2) membrane stabilization via an interaction with and regulation of the cytoskeleton, and (3) a role for presynaptic Ten-a in regulating synaptic function. These processes are further distinguished by (1) the nature of the transsynaptic interaction – homophilic interactions (between the same Teneurins) to engage partner matching and heterophilic interactions (between different Teneurins) to enable synaptic connectivity and the proper apposition of pre- and postsynaptic sites and (2) the location of cytoskeletal regulation (presynaptic cytoskeletal regulation in the CNS and postsynaptic regulation of the cytoskeleton at the NMJ). Thus, both the roles and the mechanisms governing them are conserved across processes and synapses. Here, we will highlight the contributions of Drosophila synaptic biology to our understanding of the Teneurins, discuss the mechanistic conservation that allows the Teneurins to achieve common neurodevelopmental goals, and present new data in support of these points. Finally, we will posit the next steps for understanding how this remarkably versatile family of proteins functions to control multiple distinct events in the creation of a nervous system.
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Affiliation(s)
- Alison T DePew
- Department of Neuroscience, Thomas Jefferson University, Philadelphia, PA, United States
| | - Michael A Aimino
- Department of Neuroscience, Thomas Jefferson University, Philadelphia, PA, United States
| | - Timothy J Mosca
- Department of Neuroscience, Thomas Jefferson University, Philadelphia, PA, United States
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20
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BMP signaling downstream of the Highwire E3 ligase sensitizes nociceptors. PLoS Genet 2018; 14:e1007464. [PMID: 30001326 PMCID: PMC6042685 DOI: 10.1371/journal.pgen.1007464] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Accepted: 06/01/2018] [Indexed: 01/18/2023] Open
Abstract
A comprehensive understanding of the molecular machinery important for nociception is essential to improving the treatment of pain. Here, we show that the BMP signaling pathway regulates nociception downstream of the E3 ubiquitin ligase highwire (hiw). hiw loss of function in nociceptors caused antagonistic and pleiotropic phenotypes with simultaneous insensitivity to noxious heat but sensitized responses to optogenetic activation of nociceptors. Thus, hiw functions to both positively and negatively regulate nociceptors. We find that a sensory reception-independent sensitization pathway was associated with BMP signaling. BMP signaling in nociceptors was up-regulated in hiw mutants, and nociceptor-specific expression of hiw rescued all nociception phenotypes including the increased BMP signaling. Blocking the transcriptional output of the BMP pathway with dominant negative Mad suppressed nociceptive hypersensitivity that was induced by interfering with hiw. The up-regulated BMP signaling phenotype in hiw genetic mutants could not be suppressed by mutation in wallenda suggesting that hiw regulates BMP in nociceptors via a wallenda independent pathway. In a newly established Ca2+ imaging preparation, we observed that up-regulated BMP signaling caused a significantly enhanced Ca2+ signal in the axon terminals of nociceptors that were stimulated by noxious heat. This response likely accounts for the nociceptive hypersensitivity induced by elevated BMP signaling in nociceptors. Finally, we showed that 24-hour activation of BMP signaling in nociceptors was sufficient to sensitize nociceptive responses to optogenetically-triggered nociceptor activation without altering nociceptor morphology. Overall, this study demonstrates the previously unrevealed roles of the Hiw-BMP pathway in the regulation of nociception and provides the first direct evidence that up-regulated BMP signaling physiologically sensitizes responses of nociceptors and nociception behaviors. Although pain is a universally experienced sensation that has a significant impact on human lives and society, the molecular mechanisms of pain remain poorly understood. Elucidating these mechanisms is particularly important to gaining insight into the clinical development of currently incurable chronic pain diseases. Taking an advantage of the powerful genetic model organism Drosophila melanogaster (fruit flies), we unveil the Highwire-BMP signaling pathway as a novel molecular pathway that regulates the sensitivity of nociceptive sensory neurons. Highwire and the molecular components of the BMP signaling pathway are known to be widely conserved among animal phyla, from nematode worms to humans. Since abnormal sensitivity of nociceptive sensory neurons can play a critical role in the development of chronic pain conditions, a deeper understanding of the regulation of nociceptor sensitivity has the potential to advance effective therapeutic strategies to treat difficult pain conditions.
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21
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Xing G, Li M, Sun Y, Rui M, Zhuang Y, Lv H, Han J, Jia Z, Xie W. Neurexin-Neuroligin 1 regulates synaptic morphology and functions via the WAVE regulatory complex in Drosophila neuromuscular junction. eLife 2018. [PMID: 29537369 PMCID: PMC5873926 DOI: 10.7554/elife.30457] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Neuroligins are postsynaptic adhesion molecules that are essential for postsynaptic specialization and synaptic function. But the underlying molecular mechanisms of neuroligin functions remain unclear. We found that Drosophila Neuroligin 1 (DNlg1) regulates synaptic structure and function through WAVE regulatory complex (WRC)-mediated postsynaptic actin reorganization. The disruption of DNlg1, DNlg2, or their presynaptic partner neurexin (DNrx) led to a dramatic decrease in the amount of F-actin. Further study showed that DNlg1, but not DNlg2 or DNlg3, directly interacts with the WRC via its C-terminal interacting receptor sequence. That interaction is required to recruit WRC to the postsynaptic membrane to promote F-actin assembly. Furthermore, the interaction between DNlg1 and the WRC is essential for DNlg1 to rescue the morphological and electrophysiological defects in dnlg1 mutants. Our results reveal a novel mechanism by which the DNrx-DNlg1 trans-synaptic interaction coordinates structural and functional properties at the neuromuscular junction.
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Affiliation(s)
- Guanglin Xing
- Institute of Life Sciences, the Collaborative Innovation Center for Brain Science, Southeast University, Nanjing, China
| | - Moyi Li
- Institute of Life Sciences, the Collaborative Innovation Center for Brain Science, Southeast University, Nanjing, China.,The Key Laboratory of Developmental Genes and Human Disease, Southeast University, Nanjing, China.,Co-innovation Center of Neuroregeneration, Nantong University, Nantong, China
| | - Yichen Sun
- Institute of Life Sciences, the Collaborative Innovation Center for Brain Science, Southeast University, Nanjing, China
| | - Menglong Rui
- Institute of Life Sciences, the Collaborative Innovation Center for Brain Science, Southeast University, Nanjing, China
| | - Yan Zhuang
- Institute of Life Sciences, the Collaborative Innovation Center for Brain Science, Southeast University, Nanjing, China
| | - Huihui Lv
- The Key Laboratory of Developmental Genes and Human Disease, Southeast University, Nanjing, China
| | - Junhai Han
- Institute of Life Sciences, the Collaborative Innovation Center for Brain Science, Southeast University, Nanjing, China.,The Key Laboratory of Developmental Genes and Human Disease, Southeast University, Nanjing, China.,Co-innovation Center of Neuroregeneration, Nantong University, Nantong, China
| | - Zhengping Jia
- Institute of Life Sciences, the Collaborative Innovation Center for Brain Science, Southeast University, Nanjing, China.,Neurosciences and Mental Health Program, The Hospital for Sick Children, University of Toronto, Ontario, Canada
| | - Wei Xie
- Institute of Life Sciences, the Collaborative Innovation Center for Brain Science, Southeast University, Nanjing, China.,The Key Laboratory of Developmental Genes and Human Disease, Southeast University, Nanjing, China.,Co-innovation Center of Neuroregeneration, Nantong University, Nantong, China
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