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Iosilevskii Y, Yuval O, Shemesh T, Podbilewicz B. Protocol for neuron tracing and analysis of dendritic structures from noisy microscopy images using Neuronalyzer. STAR Protoc 2024; 5:103063. [PMID: 38735040 PMCID: PMC11101970 DOI: 10.1016/j.xpro.2024.103063] [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: 08/21/2023] [Revised: 01/16/2024] [Accepted: 04/23/2024] [Indexed: 05/14/2024] Open
Abstract
Studying neuronal morphology requires imaging and accurate extraction of tree-like shapes from noisy microscopy data. Here, we present a protocol for automatic reconstruction of branched structures from microscopy images using Neuronalyzer software. We describe the steps for loading neuron images, denoising, segmentation, and tracing. We then detail feature extraction (e.g., branch curvature and junction angles), data analysis, and plotting. The software allows batch processing and statistical comparisons across datasets. Neuronalyzer is scale-free and handles noise and variation across images. For complete details on the use and execution of this protocol, please refer to Yuval et al.1.
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Affiliation(s)
- Yael Iosilevskii
- Department of Biology, Technion - Israel Institute of Technology, Haifa 32000, Israel
| | - Omer Yuval
- School of Computing, University of Leeds, Leeds, UK.
| | - Tom Shemesh
- Department of Biology, Technion - Israel Institute of Technology, Haifa 32000, Israel.
| | - Benjamin Podbilewicz
- Department of Biology, Technion - Israel Institute of Technology, Haifa 32000, Israel.
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2
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Wang J, Barr MM, Wehman AM. Extracellular vesicles. Genetics 2024:iyae088. [PMID: 38884207 DOI: 10.1093/genetics/iyae088] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2024] [Accepted: 05/21/2024] [Indexed: 06/18/2024] Open
Abstract
Extracellular vesicles (EVs) encompass a diverse array of membrane-bound organelles released outside cells in response to developmental and physiological cell needs. EVs play important roles in remodeling the shape and content of differentiating cells and can rescue damaged cells from toxic or dysfunctional content. EVs can send signals and transfer metabolites between tissues and organisms to regulate development, respond to stress or tissue damage, or alter mating behaviors. While many EV functions have been uncovered by characterizing ex vivo EVs isolated from body fluids and cultured cells, research using the nematode Caenorhabditis elegans has provided insights into the in vivo functions, biogenesis, and uptake pathways. The C. elegans EV field has also developed methods to analyze endogenous EVs within the organismal context of development and adult physiology in free-living, behaving animals. In this review, we summarize major themes that have emerged for C. elegans EVs and their relevance to human health and disease. We also highlight the diversity of biogenesis mechanisms, locations, and functions of worm EVs and discuss open questions and unexplored topics tenable in C. elegans, given the nematode model is ideal for light and electron microscopy, genetic screens, genome engineering, and high-throughput omics.
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Affiliation(s)
- Juan Wang
- Department of Genetics, Human Genetics Institute of New Jersey, Rutgers University, Piscataway, NJ 08854, USA
| | - Maureen M Barr
- Department of Genetics, Human Genetics Institute of New Jersey, Rutgers University, Piscataway, NJ 08854, USA
| | - Ann M Wehman
- Department of Biological Sciences, University of Denver, Denver, CO 80210, USA
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3
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Heiman MG, Bülow HE. Dendrite morphogenesis in Caenorhabditis elegans. Genetics 2024; 227:iyae056. [PMID: 38785371 PMCID: PMC11151937 DOI: 10.1093/genetics/iyae056] [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: 12/18/2023] [Accepted: 04/02/2024] [Indexed: 05/25/2024] Open
Abstract
Since the days of Ramón y Cajal, the vast diversity of neuronal and particularly dendrite morphology has been used to catalog neurons into different classes. Dendrite morphology varies greatly and reflects the different functions performed by different types of neurons. Significant progress has been made in our understanding of how dendrites form and the molecular factors and forces that shape these often elaborately sculpted structures. Here, we review work in the nematode Caenorhabditis elegans that has shed light on the developmental mechanisms that mediate dendrite morphogenesis with a focus on studies investigating ciliated sensory neurons and the highly elaborated dendritic trees of somatosensory neurons. These studies, which combine time-lapse imaging, genetics, and biochemistry, reveal an intricate network of factors that function both intrinsically in dendrites and extrinsically from surrounding tissues. Therefore, dendrite morphogenesis is the result of multiple tissue interactions, which ultimately determine the shape of dendritic arbors.
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Affiliation(s)
- Maxwell G Heiman
- Division of Genetics and Genomics, Boston Children's Hospital, Boston, MA 02115, USA
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Hannes E Bülow
- Department of Genetics, Albert Einstein College of Medicine, Bronx, NY 10461, USA
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY 10461, USA
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4
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Funk OH, Levy DL, Fay DS. Epidermal cell fusion promotes the transition from an embryonic to a larval transcriptome in C. elegans. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.22.595354. [PMID: 38826300 PMCID: PMC11142173 DOI: 10.1101/2024.05.22.595354] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2024]
Abstract
Cell fusion is a fundamental process in the development of multicellular organisms, yet its impact on gene regulation, particularly during crucial developmental stages, remains poorly understood. The Caenorhabditis elegans epidermis comprises 8-10 syncytial cells, with the largest integrating 139 individual nuclei through cell-cell fusion governed by the fusogenic protein EFF-1. To explore the effects of cell fusion on developmental progression and associated gene expression changes, we conducted transcriptomic analyses of eff-1 fusion-deficient mutants. Our RNAseq findings showed widespread transcriptomic changes that were enriched for epidermal genes and key molecular pathways involved in epidermal function during larval development. Subsequent single-molecule fluorescence in situ hybridization validated the altered expression of mRNA transcripts, confirming quantifiable changes in gene expression in the absence of embryonic epidermal fusion. These results underscore the significance of cell-cell fusion in shaping transcriptional programs during development and raise questions regarding the precise identities and specialized functions of different subclasses of nuclei within developing syncytial cells and tissues.
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5
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Brar HK, Dey S, Singh P, Pande D, Ghosh-Roy A. Functional Recovery Associated with Dendrite Regeneration in PVD Neuron of Caenorhabditis elegans. eNeuro 2024; 11:ENEURO.0292-23.2024. [PMID: 38548333 PMCID: PMC7615967 DOI: 10.1523/eneuro.0292-23.2024] [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: 08/12/2023] [Revised: 02/18/2024] [Accepted: 03/03/2024] [Indexed: 05/02/2024] Open
Abstract
PVD neuron of Caenorhabditis elegans is a highly polarized cell with well-defined axonal, and dendritic compartments. PVD neuron operates in multiple sensory modalities including the control of both nociceptive touch sensation and body posture. Although both the axon and dendrites of this neuron show a regeneration response following laser-assisted injury, it is rather unclear how the behavior associated with this neuron is affected by the loss of these structures. It is also unclear whether neurite regrowth would lead to functional restoration in these neurons. Upon axotomy, using a femtosecond laser, we saw that harsh touch response was specifically affected leaving the body posture unperturbed. Subsequently, recovery in the touch response is highly correlated to the axon regrowth, which was dependent on DLK-1/MLK-1 MAP Kinase. Dendrotomy of both major and minor primary dendrites affected the wavelength and amplitude of sinusoidal movement without any apparent effect on harsh touch response. We further correlated the recovery in posture behavior to the type of dendrite regeneration events. We found that dendrite regeneration through the fusion and reconnection between the proximal and distal branches of the injured dendrite corresponded to improved recovery in posture. Our data revealed that the axons and dendrites of PVD neurons regulate the nociception and proprioception in worms, respectively. It also revealed that dendrite and axon regeneration lead to the restoration of these differential sensory modalities.
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Affiliation(s)
- Harjot Kaur Brar
- Department of Cellular and Molecular Neuroscience, National Brain Research Centre, Manesar 122052, Haryana, India
| | - Swagata Dey
- Department of Cellular and Molecular Neuroscience, National Brain Research Centre, Manesar 122052, Haryana, India
| | - Pallavi Singh
- Department of Cellular and Molecular Neuroscience, National Brain Research Centre, Manesar 122052, Haryana, India
| | - Devashish Pande
- Department of Cellular and Molecular Neuroscience, National Brain Research Centre, Manesar 122052, Haryana, India
| | - Anindya Ghosh-Roy
- Department of Cellular and Molecular Neuroscience, National Brain Research Centre, Manesar 122052, Haryana, India
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6
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Singh P, Selvarasu K, Ghosh-Roy A. Optimization of RNAi efficiency in PVD neuron of C. elegans. PLoS One 2024; 19:e0298766. [PMID: 38498505 PMCID: PMC10947639 DOI: 10.1371/journal.pone.0298766] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Accepted: 01/31/2024] [Indexed: 03/20/2024] Open
Abstract
PVD neuron of C. elegans has become an attractive model for the study of dendrite development and regeneration due to its elaborate and stereotype dendrite morphology. RNA interference (RNAi) by feeding E. coli expressing dsRNA has been the basis of several genome wide screens performed using C. elegans. However, the feeding method often fails when it comes to knocking down genes in nervous system. In order to optimize the RNAi conditions for PVD neuron, we fed the worm strains with E. coli HT115 bacteria expressing dsRNA against mec-3, hpo-30, and tiam-1, whose loss of function are known to show dendrite morphology defects in PVD neuron. We found that RNAi of these genes in the available sensitive backgrounds including the one expresses sid-1 under unc-119 promoter, although resulted in reduction of dendrite branching, the phenotypes were significantly modest compared to the respective loss of function mutants. In order to enhance RNAi in PVD neurons, we generated a strain that expressed sid-1 under the promoter mec-3, which exhibits strong expression in PVD. When Pmec-3::sid-1 is expressed in either nre-1(-)lin-15b(-) or lin-15b(-) backgrounds, the higher order branching phenotype after RNAi of mec-3, hpo-30, and tiam-1 was significantly enhanced as compared to the genetic background alone. Moreover, knockdown of genes playing role in dendrite regeneration in the nre-1(-)lin-15b(-), Pmec-3-sid-1[+] background resulted in significant reduction in dendrite regeneration following laser injury. The extent of dendrite regrowth due to the RNAi of aff-1 or ced-10 in our optimized strain was comparable to that of aff-1 and ced-10 mutants. Essentially, our strain expressing sid-1 in PVD neuron, provides an RNAi optimized platform for high throughput screening of genes involved in PVD development, maintenance and regeneration.
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Affiliation(s)
- Pallavi Singh
- Department of Cellular & Molecular Neuroscience, National Brain Research Centre, Manesar, Haryana, India
| | - Kavinila Selvarasu
- Department of Cellular & Molecular Neuroscience, National Brain Research Centre, Manesar, Haryana, India
| | - Anindya Ghosh-Roy
- Department of Cellular & Molecular Neuroscience, National Brain Research Centre, Manesar, Haryana, India
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7
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Freitag R, Stern J, Masters J, Kowalski G, Miller DM, Eley JG. High-Dose Ionizing Radiation Impairs Healthy Dendrite Growth in C. elegans. Adv Radiat Oncol 2024; 9:101415. [PMID: 38379892 PMCID: PMC10876608 DOI: 10.1016/j.adro.2023.101415] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Accepted: 11/19/2023] [Indexed: 02/22/2024] Open
Abstract
Purpose The nervous system is vulnerable to radiation damage, and further optimization is required to increase the efficacy of radiation therapy while reducing harm to neurons. Given recent developments in heavy ion therapy, experimental models would be valuable to improve these therapies. We used the nematode Caenorhabditis elegans (C. elegans) to evaluate the effects of high-dose radiation on neuron development. Methods and Materials In this study, we used confocal microscopy to assess dendritic growth of the PVD nociceptor after high-dose gamma-irradiation from a Cs-137 source. Results Irradiation during an early larval stage (L2) delayed overall development but also independently impaired dendrite outgrowth in the PVD nociceptive neuron. Irradiation at L4 larval stage did not result in significant alterations in dendrite morphology. Conclusions The nematode C. elegans can serve as a high-throughput model to study the effects of high-dose radiation on dendrite growth. We propose that C. elegans can be useful for studies of experimental radiation therapy modalities and dose rates for translational research.
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Affiliation(s)
- Robert Freitag
- Program in Neuroscience, Vanderbilt University, Nashville, Tennessee
| | - Jamie Stern
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, Tennessee
- Agilent Technologies, Winooski, Vermont
| | - Joseph Masters
- Department of Radiation Oncology, Vanderbilt University School of Medicine, Nashville Tennessee
| | - Greta Kowalski
- Department of Radiation Oncology, Vanderbilt University School of Medicine, Nashville Tennessee
| | - David M. Miller
- Program in Neuroscience, Vanderbilt University, Nashville, Tennessee
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, Tennessee
| | - John G. Eley
- Department of Radiation Oncology, Vanderbilt University School of Medicine, Nashville Tennessee
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8
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Majeed M, Han H, Zhang K, Cao WX, Liao CP, Hobert O, Lu H. Toolkits for detailed and high-throughput interrogation of synapses in C. elegans. eLife 2024; 12:RP91775. [PMID: 38224479 PMCID: PMC10945580 DOI: 10.7554/elife.91775] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2024] Open
Abstract
Visualizing synaptic connectivity has traditionally relied on time-consuming electron microscopy-based imaging approaches. To scale the analysis of synaptic connectivity, fluorescent protein-based techniques have been established, ranging from the labeling of specific pre- or post-synaptic components of chemical or electrical synapses to transsynaptic proximity labeling technology such as GRASP and iBLINC. In this paper, we describe WormPsyQi, a generalizable image analysis pipeline that automatically quantifies synaptically localized fluorescent signals in a high-throughput and robust manner, with reduced human bias. We also present a resource of 30 transgenic strains that label chemical or electrical synapses throughout the nervous system of the nematode Caenorhabditis elegans, using CLA-1, RAB-3, GRASP (chemical synapses), or innexin (electrical synapse) reporters. We show that WormPsyQi captures synaptic structures in spite of substantial heterogeneity in neurite morphology, fluorescence signal, and imaging parameters. We use these toolkits to quantify multiple obvious and subtle features of synapses - such as number, size, intensity, and spatial distribution of synapses - in datasets spanning various regions of the nervous system, developmental stages, and sexes. Although the pipeline is described in the context of synapses, it may be utilized for other 'punctate' signals, such as fluorescently tagged neurotransmitter receptors and cell adhesion molecules, as well as proteins in other subcellular contexts. By overcoming constraints on time, sample size, cell morphology, and phenotypic space, this work represents a powerful resource for further analysis of synapse biology in C. elegans.
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Affiliation(s)
- Maryam Majeed
- Department of Biological Sciences, Howard Hughes Medical Institute, Columbia UniversityNew YorkUnited States
| | - Haejun Han
- School of Electrical and Computer Engineering, Georgia Institute of TechnologyAtlantaUnited States
- The Parker H Petit Institute of Bioengineering and Bioscience, Georgia Institute of TechnologyAtlantaUnited States
| | - Keren Zhang
- School of Chemical and Biomolecular Engineering, Georgia Institute of TechnologyAtlantaUnited States
| | - Wen Xi Cao
- Department of Biological Sciences, Howard Hughes Medical Institute, Columbia UniversityNew YorkUnited States
| | - Chien-Po Liao
- Department of Biological Sciences, Howard Hughes Medical Institute, Columbia UniversityNew YorkUnited States
| | - Oliver Hobert
- Department of Biological Sciences, Howard Hughes Medical Institute, Columbia UniversityNew YorkUnited States
| | - Hang Lu
- The Parker H Petit Institute of Bioengineering and Bioscience, Georgia Institute of TechnologyAtlantaUnited States
- School of Chemical and Biomolecular Engineering, Georgia Institute of TechnologyAtlantaUnited States
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9
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Moroz LL. Syncytial nets vs. chemical signaling: emerging properties of alternative integrative systems. Front Cell Dev Biol 2023; 11:1320209. [PMID: 38125877 PMCID: PMC10730927 DOI: 10.3389/fcell.2023.1320209] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2023] [Accepted: 11/22/2023] [Indexed: 12/23/2023] Open
Affiliation(s)
- Leonid L. Moroz
- Department of Neuroscience, University of Florida, Gainesville, FL, United States
- Whitney Laboratory for Marine Bioscience, University of Florida, St. Augustine, FL, United States
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10
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Land R, Fetter R, Liang X, Tzeng CP, Taylor CA, Shen K. Endoplasmic Reticulum Exit Sites scale with somato-dendritic size in neurons. Mol Biol Cell 2023; 34:ar106. [PMID: 37556208 PMCID: PMC10559313 DOI: 10.1091/mbc.e23-03-0090] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Revised: 07/10/2023] [Accepted: 08/02/2023] [Indexed: 08/11/2023] Open
Abstract
Nervous systems exhibit dramatic diversity in cell morphology and size. How neurons regulate their biosynthetic and secretory machinery to support such diversity is not well understood. Endoplasmic reticulum exit sites (ERESs) are essential for maintaining secretory flux, and are required for normal dendrite development, but how neurons of different size regulate secretory capacity remains unknown. In Caenorhabditis elegans, we find that the ERES number is strongly correlated with the size of a neuron's dendritic arbor. The elaborately branched sensory neuron, PVD, has especially high ERES numbers. Asymmetric cell division provides PVD with a large initial cell size critical for rapid establishment of PVD's high ERES number before neurite outgrowth, and these ERESs are maintained throughout development. Maintenance of ERES number requires the cell fate transcription factor MEC-3, C. elegans TOR (ceTOR/let-363), and nutrient availability, with mec-3 and ceTOR/let-363 mutant PVDs both displaying reductions in ERES number, soma size, and dendrite size. Notably, mec-3 mutant animals exhibit reduced expression of a ceTOR/let-363 reporter in PVD, and starvation reduces ERES number and somato-dendritic size in a manner genetically redundant with ceTOR/let-363 perturbation. Our data suggest that both asymmetric cell division and nutrient sensing pathways regulate secretory capacities to support elaborate dendritic arbors.
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Affiliation(s)
- Ruben Land
- Department of Biology, Stanford University, Stanford, CA 94305
- Neurosciences IDP, Stanford University, Stanford, CA 94305
| | - Richard Fetter
- Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305
| | - Xing Liang
- Department of Biology, Stanford University, Stanford, CA 94305
| | - Christopher P. Tzeng
- Department of Biology, Stanford University, Stanford, CA 94305
- Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305
| | - Caitlin A. Taylor
- Department of Biology, Stanford University, Stanford, CA 94305
- Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305
| | - Kang Shen
- Department of Biology, Stanford University, Stanford, CA 94305
- Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305
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11
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Ramirez-Suarez NJ, Belalcazar HM, Rahman M, Trivedi M, Tang LTH, Bülow HE. Convertase-dependent regulation of membrane-tethered and secreted ligands tunes dendrite adhesion. Development 2023; 150:dev201208. [PMID: 37721334 PMCID: PMC10546877 DOI: 10.1242/dev.201208] [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: 08/17/2022] [Accepted: 08/01/2023] [Indexed: 09/19/2023]
Abstract
During neural development, cellular adhesion is crucial for interactions among and between neurons and surrounding tissues. This function is mediated by conserved cell adhesion molecules, which are tightly regulated to allow for coordinated neuronal outgrowth. Here, we show that the proprotein convertase KPC-1 (homolog of mammalian furin) regulates the Menorin adhesion complex during development of PVD dendritic arbors in Caenorhabditis elegans. We found a finely regulated antagonistic balance between PVD-expressed KPC-1 and the epidermally expressed putative cell adhesion molecule MNR-1 (Menorin). Genetically, partial loss of mnr-1 suppressed partial loss of kpc-1, and both loss of kpc-1 and transgenic overexpression of mnr-1 resulted in indistinguishable phenotypes in PVD dendrites. This balance regulated cell-surface localization of the DMA-1 leucine-rich transmembrane receptor in PVD neurons. Lastly, kpc-1 mutants showed increased amounts of MNR-1 and decreased amounts of muscle-derived LECT-2 (Chondromodulin II), which is also part of the Menorin adhesion complex. These observations suggest that KPC-1 in PVD neurons directly or indirectly controls the abundance of proteins of the Menorin adhesion complex from adjacent tissues, thereby providing negative feedback from the dendrite to the instructive cues of surrounding tissues.
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Affiliation(s)
| | - Helen M. Belalcazar
- Department of Genetics, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Maisha Rahman
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Meera Trivedi
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Leo T. H. Tang
- Department of Genetics, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Hannes E. Bülow
- Department of Genetics, Albert Einstein College of Medicine, Bronx, NY 10461, USA
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY 10461, USA
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12
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Fang J, Wang J, Wang Y, Liu X, Chen B, Zou W. Ribo-On and Ribo-Off tools using a self-cleaving ribozyme allow manipulation of endogenous gene expression in C. elegans. Commun Biol 2023; 6:816. [PMID: 37542105 PMCID: PMC10403566 DOI: 10.1038/s42003-023-05184-4] [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: 08/31/2022] [Accepted: 07/26/2023] [Indexed: 08/06/2023] Open
Abstract
Investigating gene function relies on the efficient manipulation of endogenous gene expression. Currently, a limited number of tools are available to robustly manipulate endogenous gene expression between "on" and "off" states. In this study, we insert a 63 bp coding sequence of T3H38 ribozyme into the 3' untranslated region (UTR) of C. elegans endogenous genes using the CRISPR/Cas9 technology, which reduces the endogenous gene expression to a nearly undetectable level and generated loss-of-function phenotypes similar to that of the genetic null animals. To achieve conditional knockout, a cassette of loxP-flanked transcriptional termination signal and ribozyme is inserted into the 3' UTR of endogenous genes, which eliminates gene expression spatially or temporally via the controllable expression of the Cre recombinase. Conditional endogenous gene turn-on can be achieved by either injecting morpholino, which blocks the ribozyme self-cleavage activity or using the Cre recombinase to remove the loxP-flanked ribozyme. Together, our results demonstrate that these ribozyme-based tools can efficiently manipulate endogenous gene expression both in space and time and expand the toolkit for studying the functions of endogenous genes.
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Affiliation(s)
- Jie Fang
- The Fourth Affiliated Hospital, Zhejiang University School of Medicine, 322000, Yiwu, China
- Institute of Translational Medicine, Zhejiang University, 310058, Hangzhou, China
- Department of Cell Biology and Bone Marrow Transplantation Center of the First Affiliated Hospital, Zhejiang University School of Medicine, 310058, Hangzhou, China
| | - Jie Wang
- The Fourth Affiliated Hospital, Zhejiang University School of Medicine, 322000, Yiwu, China
- Institute of Translational Medicine, Zhejiang University, 310058, Hangzhou, China
| | - Yuzhi Wang
- The Fourth Affiliated Hospital, Zhejiang University School of Medicine, 322000, Yiwu, China
- Institute of Translational Medicine, Zhejiang University, 310058, Hangzhou, China
| | - Xiaofan Liu
- The Fourth Affiliated Hospital, Zhejiang University School of Medicine, 322000, Yiwu, China
- Institute of Translational Medicine, Zhejiang University, 310058, Hangzhou, China
| | - Baohui Chen
- Department of Cell Biology and Bone Marrow Transplantation Center of the First Affiliated Hospital, Zhejiang University School of Medicine, 310058, Hangzhou, China.
- Zhejiang Laboratory for Systems & Precision Medicine, Zhejiang University Medical Center, Hangzhou, China.
- Institute of Hematology, Zhejiang University & Zhejiang Engineering Laboratory for Stem Cell and Immunotherapy, Hangzhou, China.
- Zhejiang Provincial Key Laboratory of Genetic & Developmental Disorders, Hangzhou, China.
| | - Wei Zou
- The Fourth Affiliated Hospital, Zhejiang University School of Medicine, 322000, Yiwu, China.
- Institute of Translational Medicine, Zhejiang University, 310058, Hangzhou, China.
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13
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Hertzler JI, Bernard AR, Rolls MM. Dendrite regeneration mediates functional recovery after complete dendrite removal. Dev Biol 2023; 497:18-25. [PMID: 36870669 PMCID: PMC10073339 DOI: 10.1016/j.ydbio.2023.03.001] [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] [Revised: 02/28/2023] [Accepted: 03/02/2023] [Indexed: 03/06/2023]
Abstract
Unlike many cell types, neurons are not typically replaced if damaged. Therefore, regeneration of damaged cellular domains is critical for maintenance of neuronal function. While axon regeneration has been documented for several hundred years, it has only recently become possible to determine whether neurons respond to dendrite removal with regeneration. Regrowth of dendrite arbors has been documented in invertebrate and vertebrate model systems, but whether it leads to functional restoration of a circuit remains unknown. To test whether dendrite regeneration restores function, we used larval Drosophila nociceptive neurons. Their dendrites detect noxious stimuli to initiate escape behavior. Previous studies of Drosophila sensory neurons have shown that dendrites of single neurons regrow after laser severing. We removed dendrites from 16 neurons per animal to clear most of the dorsal surface of nociceptive innervation. As expected, this reduced aversive responses to noxious touch. Surprisingly, behavior was completely restored 24 h after injury, at the stage when dendrite regeneration has begun, but the new arbor has only covered a small portion of its former territory. This behavioral recovery required regenerative outgrowth as it was eliminated in a genetic background in which new growth is blocked. We conclude that dendrite regeneration can restore behavior.
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Affiliation(s)
- J Ian Hertzler
- Biochemistry and Molecular Biology and the Huck Institutes of the Life Sciences, University Park, PA, 16802, USA
| | - Annabelle R Bernard
- Biochemistry and Molecular Biology and the Huck Institutes of the Life Sciences, University Park, PA, 16802, USA
| | - Melissa M Rolls
- Biochemistry and Molecular Biology and the Huck Institutes of the Life Sciences, University Park, PA, 16802, USA.
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14
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Burkhardt P, Colgren J, Medhus A, Digel L, Naumann B, Soto-Angel JJ, Nordmann EL, Sachkova MY, Kittelmann M. Syncytial nerve net in a ctenophore adds insights on the evolution of nervous systems. Science 2023; 380:293-297. [PMID: 37079688 DOI: 10.1126/science.ade5645] [Citation(s) in RCA: 19] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/22/2023]
Abstract
A fundamental breakthrough in neurobiology has been the formulation of the neuron doctrine by Santiago Ramón y Cajal, which stated that the nervous system is composed of discrete cells. Electron microscopy later confirmed the doctrine and allowed the identification of synaptic connections. In this work, we used volume electron microscopy and three-dimensional reconstructions to characterize the nerve net of a ctenophore, a marine invertebrate that belongs to one of the earliest-branching animal lineages. We found that neurons in the subepithelial nerve net have a continuous plasma membrane that forms a syncytium. Our findings suggest fundamental differences of nerve net architectures between ctenophores and cnidarians or bilaterians and offer an alternative perspective on neural network organization and neurotransmission.
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Affiliation(s)
- Pawel Burkhardt
- Michael Sars Centre, University of Bergen, 5008 Bergen, Norway
| | - Jeffrey Colgren
- Michael Sars Centre, University of Bergen, 5008 Bergen, Norway
| | - Astrid Medhus
- Michael Sars Centre, University of Bergen, 5008 Bergen, Norway
| | - Leonid Digel
- Michael Sars Centre, University of Bergen, 5008 Bergen, Norway
| | - Benjamin Naumann
- Institut für Biowissenschaften, Allgemeine und Spezielle Zoologie, Universität Rostock, 18055 Rostock, Germany
| | | | | | | | - Maike Kittelmann
- Department of Biological and Medical Sciences, Oxford Brookes University, Oxford OX3 0BP, UK
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15
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Liu X, Zhao Y, Zou W. Molecular mechanisms of neurite regeneration and repair: insights from C. elegans and Drosophila. CELL REGENERATION (LONDON, ENGLAND) 2023; 12:12. [PMID: 37005942 PMCID: PMC10067779 DOI: 10.1186/s13619-022-00155-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Accepted: 12/01/2022] [Indexed: 04/04/2023]
Abstract
The difficulties of injured and degenerated neurons to regenerate neurites and regain functions are more significant than in other body tissues, making neurodegenerative and related diseases hard to cure. Uncovering the secrets of neural regeneration and how this process may be inhibited after injury will provide insights into novel management and potential treatments for these diseases. Caenorhabditis elegans and Drosophila melanogaster are two of the most widely used and well-established model organisms endowed with advantages in genetic manipulation and live imaging to explore this fundamental question about neural regeneration. Here, we review the classical models and techniques, and the involvement and cooperation of subcellular structures during neurite regeneration using these two organisms. Finally, we list several important open questions that we look forward to inspiring future research.
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Affiliation(s)
- Xiaofan Liu
- The Fourth Affiliated Hospital, Zhejiang University School of Medicine, Yiwu, China
- Institute of Translational Medicine, Zhejiang University, Hangzhou, China
| | - Yuqing Zhao
- The Fourth Affiliated Hospital, Zhejiang University School of Medicine, Yiwu, China
- Institute of Translational Medicine, Zhejiang University, Hangzhou, China
- Institute of Zhejiang University and University of Edinburgh, Jiaxing, China
| | - Wei Zou
- The Fourth Affiliated Hospital, Zhejiang University School of Medicine, Yiwu, China.
- Institute of Translational Medicine, Zhejiang University, Hangzhou, China.
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16
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Yoshiyama KO, Okamoto NL, Hidema J, Higashitani A. 222 nm far-UVC efficiently introduces nerve damage in Caenorhabditis elegans. PLoS One 2023; 18:e0281162. [PMID: 36719882 PMCID: PMC9888708 DOI: 10.1371/journal.pone.0281162] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Accepted: 01/16/2023] [Indexed: 02/01/2023] Open
Abstract
Far-ultraviolet radiation C light (far-UVC; 222 nm wavelength) has received attention as a safer light for killing pathogenic bacteria and viruses, as no or little DNA damage is observed after irradiation in mammalian skin models. Far-UVC does not penetrate deeply into tissues; therefore, it cannot reach the underlying critical basal cells. However, it was unclear whether far-UVC (222-UVC) irradiation could cause more biological damage at shallower depths than the 254 nm UVC irradiation (254-UVC), which penetrates more deeply. This study investigated the biological effects of 222- and 254-UVC on the small and transparent model organism Caenorhabditis elegans. At the same energy level of irradiation, 222-UVC introduced slightly less cyclobutane pyrimidine dimer damage to naked DNA in solution than 254-UVC. The survival of eggs laid during 0-4 h after irradiation showed a marked decrease with 254-UVC but not 222-UVC. In addition, defect of chromosomal condensation was observed in a full-grown oocyte by 254-UVC irradiation. In contrast, 222-UVC had a significant effect on the loss of motility of C. elegans. The sensory nervous system, which includes dopamine CEP and PVD neurons on the body surface, was severely damaged by 222-UVC, but not by the same dose of 254-UVC. Interestingly, increasing 254-UVC irradiation by about 10-fold causes similar damage to CEP neurons. These results suggest that 222-UVC is less penetrating, so energy transfer occurs more effectively in tissues near the surface, causing more severe damage than 254-UVC.
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Affiliation(s)
| | | | - Jun Hidema
- Graduate School of Life Sciences, Tohoku University, Sendai, Japan
- Division for the Establishment of Frontier Sciences of the Organization for Advanced Studies, Tohoku University, Sendai, Japan
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17
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Moroz LL, Romanova DY. Alternative neural systems: What is a neuron? (Ctenophores, sponges and placozoans). Front Cell Dev Biol 2022; 10:1071961. [PMID: 36619868 PMCID: PMC9816575 DOI: 10.3389/fcell.2022.1071961] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Accepted: 12/13/2022] [Indexed: 12/24/2022] Open
Abstract
How to make a neuron, a synapse, and a neural circuit? Is there only one 'design' for a neural architecture with a universally shared genomic blueprint across species? The brief answer is "No." Four early divergent lineages from the nerveless common ancestor of all animals independently evolved distinct neuroid-type integrative systems. One of these is a subset of neural nets in comb jellies with unique synapses; the second lineage is the well-known Cnidaria + Bilateria; the two others are non-synaptic neuroid systems in sponges and placozoans. By integrating scRNA-seq and microscopy data, we revise the definition of neurons as synaptically-coupled polarized and highly heterogenous secretory cells at the top of behavioral hierarchies with learning capabilities. This physiological (not phylogenetic) definition separates 'true' neurons from non-synaptically and gap junction-coupled integrative systems executing more stereotyped behaviors. Growing evidence supports the hypothesis of multiple origins of neurons and synapses. Thus, many non-bilaterian and bilaterian neuronal classes, circuits or systems are considered functional rather than genetic categories, composed of non-homologous cell types. In summary, little-explored examples of convergent neuronal evolution in representatives of early branching metazoans provide conceptually novel microanatomical and physiological architectures of behavioral controls in animals with prospects of neuro-engineering and synthetic biology.
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Affiliation(s)
- Leonid L. Moroz
- Departments of Neuroscience and McKnight Brain Institute, University of Florida, Gainesville, FL, United States,Whitney Laboratory for Marine Bioscience, University of Florida, St. Augustine, FL, United States,*Correspondence: Leonid L. Moroz, ; Daria Y. Romanova,
| | - Daria Y. Romanova
- Institute of Higher Nervous Activity and Neurophysiology of RAS, 5A Butlerova, Moscow, Russia,*Correspondence: Leonid L. Moroz, ; Daria Y. Romanova,
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18
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Smith JJ, Kenny IW, Wolff C, Cray R, Kumar A, Sherwood DR, Matus DQ. A light sheet fluorescence microscopy protocol for Caenorhabditis elegans larvae and adults. Front Cell Dev Biol 2022; 10:1012820. [PMID: 36274853 PMCID: PMC9586288 DOI: 10.3389/fcell.2022.1012820] [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: 08/05/2022] [Accepted: 09/20/2022] [Indexed: 01/07/2023] Open
Abstract
Light sheet fluorescence microscopy (LSFM) has become a method of choice for live imaging because of its fast acquisition and reduced photobleaching and phototoxicity. Despite the strengths and growing availability of LSFM systems, no generalized LSFM mounting protocol has been adapted for live imaging of post-embryonic stages of C. elegans. A major challenge has been to develop methods to limit animal movement using a mounting media that matches the refractive index of the optical system. Here, we describe a simple mounting and immobilization protocol using a refractive-index matched UV-curable hydrogel within fluorinated ethylene propylene (FEP) tubes for efficient and reliable imaging of larval and adult C. elegans stages.
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Affiliation(s)
- Jayson J. Smith
- Department of Neurobiology, University of Chicago, Chicago, IL, United States,University of Chicago Neuroscience Institute, Chicago, IL, United States,Embryology: Modern Concepts and Techniques, Marine Biological Laboratory, Woods Hole, MA, United States
| | - Isabel W. Kenny
- Embryology: Modern Concepts and Techniques, Marine Biological Laboratory, Woods Hole, MA, United States,Department of Biology, Duke University, Durham, NC, United States
| | - Carsten Wolff
- Embryology: Modern Concepts and Techniques, Marine Biological Laboratory, Woods Hole, MA, United States,Marine Biological Laboratory, Woods Hole, MA, United States
| | - Rachel Cray
- Marine Biological Laboratory, Woods Hole, MA, United States
| | - Abhishek Kumar
- Embryology: Modern Concepts and Techniques, Marine Biological Laboratory, Woods Hole, MA, United States,Marine Biological Laboratory, Woods Hole, MA, United States
| | - David R. Sherwood
- Embryology: Modern Concepts and Techniques, Marine Biological Laboratory, Woods Hole, MA, United States,Department of Biology, Duke University, Durham, NC, United States,*Correspondence: David R. Sherwood, ; David Q. Matus,
| | - David Q. Matus
- Embryology: Modern Concepts and Techniques, Marine Biological Laboratory, Woods Hole, MA, United States,Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY, United States,*Correspondence: David R. Sherwood, ; David Q. Matus,
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19
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Recruitment of tetraspanin TSP-15 to epidermal wounds promotes plasma membrane repair in C. elegans. Dev Cell 2022; 57:1630-1642.e4. [PMID: 35777354 DOI: 10.1016/j.devcel.2022.06.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Revised: 04/26/2022] [Accepted: 06/07/2022] [Indexed: 01/14/2023]
Abstract
Maintaining the integrity of the plasma membrane after cellular damage is essential for cell survival. However, it is unclear how cells repair large membrane injuries in vivo. Here, we report that the tetraspanin protein, TSP-15, is recruited to large membrane wounds and forms a ring-like structure in C. elegans epidermis and promotes membrane repair after an injury. TSP-15 recruits from the adjacent region underneath the plasma membrane to the wound site in a RAB-5-dependent manner upon membrane damage. Genetic and live-imaging analysis suggested that the endosomal sorting complex required for transport III (ESCRT III) is necessary for recruiting TSP-15 from the early endosome to the damaged membrane. Moreover, TSP-15 interacts with and is required for the accumulation of t-SNARE protein Syntaxin-2, which facilitates membrane repair. These findings provide valuable insights into the role of the conserved tetraspanin TSP-15 in the cellular repair of large wounds resulting from environmental insults.
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20
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Rahman M, Ramirez‐Suarez NJ, Diaz‐Balzac CA, Bülow HE. Specific N-glycans regulate an extracellular adhesion complex during somatosensory dendrite patterning. EMBO Rep 2022; 23:e54163. [PMID: 35586945 PMCID: PMC9253746 DOI: 10.15252/embr.202154163] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Revised: 04/13/2022] [Accepted: 04/22/2022] [Indexed: 09/19/2023] Open
Abstract
N-glycans are molecularly diverse sugars borne by over 70% of proteins transiting the secretory pathway and have been implicated in protein folding, stability, and localization. Mutations in genes important for N-glycosylation result in congenital disorders of glycosylation that are often associated with intellectual disability. Here, we show that structurally distinct N-glycans regulate an extracellular protein complex involved in the patterning of somatosensory dendrites in Caenorhabditis elegans. Specifically, aman-2/Golgi alpha-mannosidase II, a conserved key enzyme in the biosynthesis of specific N-glycans, regulates the activity of the Menorin adhesion complex without obviously affecting the protein stability and localization of its components. AMAN-2 functions cell-autonomously to allow for decoration of the neuronal transmembrane receptor DMA-1/LRR-TM with the correct set of high-mannose/hybrid/paucimannose N-glycans. Moreover, distinct types of N-glycans on specific N-glycosylation sites regulate DMA-1/LRR-TM receptor function, which, together with three other extracellular proteins, forms the Menorin adhesion complex. In summary, specific N-glycan structures regulate dendrite patterning by coordinating the activity of an extracellular adhesion complex, suggesting that the molecular diversity of N-glycans can contribute to developmental specificity in the nervous system.
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Affiliation(s)
- Maisha Rahman
- Department of GeneticsAlbert Einstein College of MedicineBronxNYUSA
- Dominick P. Purpura Department of NeuroscienceAlbert Einstein College of MedicineBronxNYUSA
| | - Nelson J Ramirez‐Suarez
- Department of GeneticsAlbert Einstein College of MedicineBronxNYUSA
- Present address:
Institute of Science and Technology AustriaKlosterneuburgAustria
| | - Carlos A Diaz‐Balzac
- Department of GeneticsAlbert Einstein College of MedicineBronxNYUSA
- Present address:
University of RochesterRochesterNYUSA
| | - Hannes E Bülow
- Department of GeneticsAlbert Einstein College of MedicineBronxNYUSA
- Dominick P. Purpura Department of NeuroscienceAlbert Einstein College of MedicineBronxNYUSA
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21
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Brar HK, Dey S, Bhardwaj S, Pande D, Singh P, Dey S, Ghosh-Roy A. Dendrite regeneration in C. elegans is controlled by the RAC GTPase CED-10 and the RhoGEF TIAM-1. PLoS Genet 2022; 18:e1010127. [PMID: 35344539 PMCID: PMC8989329 DOI: 10.1371/journal.pgen.1010127] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Revised: 04/07/2022] [Accepted: 02/28/2022] [Indexed: 01/30/2023] Open
Abstract
Neurons are vulnerable to physical insults, which compromise the integrity of both dendrites and axons. Although several molecular pathways of axon regeneration are identified, our knowledge of dendrite regeneration is limited. To understand the mechanisms of dendrite regeneration, we used the PVD neurons in C. elegans with stereotyped branched dendrites. Using femtosecond laser, we severed the primary dendrites and axon of this neuron. After severing the primary dendrites near the cell body, we observed sprouting of new branches from the proximal site within 6 hours, which regrew further with time in an unstereotyped manner. This was accompanied by reconnection between the proximal and distal dendrites, and fusion among the higher-order branches as reported before. We quantified the regeneration pattern into three aspects–territory length, number of branches, and fusion phenomena. Axonal injury causes a retraction of the severed end followed by a Dual leucine zipper kinase-1 (DLK-1) dependent regrowth from the severed end. We tested the roles of the major axon regeneration signalling hubs such as DLK-1-RPM-1, cAMP elevation, let-7 miRNA, AKT-1, Phosphatidylserine (PS) exposure/PS in dendrite regeneration. We found that neither dendrite regrowth nor fusion was affected by the axon injury pathway molecules. Surprisingly, we found that the RAC GTPase, CED-10 and its upstream GEF, TIAM-1 play a cell-autonomous role in dendrite regeneration. Additionally, the function of CED-10 in epidermal cell is critical for post-dendrotomy fusion phenomena. This work describes a novel regulatory mechanism of dendrite regeneration and provides a framework for understanding the cellular mechanism of dendrite regeneration using PVD neuron as a model system. The knowledge of the repair of injured neural circuits comes from the study of the regeneration of injured axons. The information receiving neurites, namely dendrites, are also vulnerable to physical insult during stroke and trauma. However, little knowledge is available on the mechanism of dendrite regeneration since the study of Cajal. In order to get insight into this process, we severed both axon and dendrites of PVD neuron in C. elegans using laser. By comparing the roles of axon regeneration pathways in both dendrite and axon regeneration in this neuron, we found that dendrite regeneration is independent of molecular mechanisms involving axon regrowth. We discovered that dendrite regeneration is dependent on the RAC GTPase CED-10 and GEF TIAM-1. Moreover, we found that CED-10 plays roles within both neuron and in the surrounding epithelia for mounting regeneration response to dendrite injury. This work provides mechanistic insight into the process of dendrite repair after physical injury.
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Affiliation(s)
- Harjot Kaur Brar
- Department of Cellular & Molecular Neuroscience, National Brain Research Centre, Manesar, Haryana, India
| | - Swagata Dey
- Department of Cellular & Molecular Neuroscience, National Brain Research Centre, Manesar, Haryana, India
| | - Smriti Bhardwaj
- Department of Cellular & Molecular Neuroscience, National Brain Research Centre, Manesar, Haryana, India
| | - Devashish Pande
- Department of Cellular & Molecular Neuroscience, National Brain Research Centre, Manesar, Haryana, India
| | - Pallavi Singh
- Department of Cellular & Molecular Neuroscience, National Brain Research Centre, Manesar, Haryana, India
| | - Shirshendu Dey
- Fluorescence Microscopy Division, Bruker India Scientific Pvt. Ltd., International Trade Tower, Nehru Place, New Delhi, India
| | - Anindya Ghosh-Roy
- Department of Cellular & Molecular Neuroscience, National Brain Research Centre, Manesar, Haryana, India
- * E-mail:
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22
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Kaur S, Sang Y, Aballay A. Myotubularin-related protein protects against neuronal degeneration mediated by oxidative stress or infection. J Biol Chem 2022; 298:101614. [PMID: 35101447 PMCID: PMC8889260 DOI: 10.1016/j.jbc.2022.101614] [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: 08/04/2021] [Revised: 01/08/2022] [Accepted: 01/10/2022] [Indexed: 11/04/2022] Open
Abstract
Microbial infections have been linked to the onset and severity of neurodegenerative diseases such as amyotrophic lateral sclerosis, multiple sclerosis, Alzheimer's disease, but the underlying mechanisms remain largely unknown. Here, we used a genetic screen for genes involved in protection from infection-associated neurodegeneration and identified the gene mtm-10. We then validated the role of the encoded myotubularin-related protein, MTM-10, in protecting the dendrites of Caenorhabditis elegans from degeneration mediated by oxidative stress or Pseudomonas aeruginosa infection. Further experiments indicated that mtm-10 is expressed in the AWC neurons of C. elegans, where it functions in a cell-autonomous manner to protect the dendrite degeneration caused by pathogen infection. We also confirm that the changes observed in the dendrites of the animals were not because of premature death or overall sickness. Finally, our studies indicated that mtm-10 functions in AWC neurons to preserve chemosensation after pathogen infection. These results reveal an essential role for myotubularin-related protein 10 in the protection of dendrite morphology and function against the deleterious effects of oxidative stress or infection.
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Affiliation(s)
- Supender Kaur
- Department of Molecular Microbiology & Immunology, Oregon Health & Science University, Portland, Oregon, USA
| | - Yu Sang
- Department of Molecular Microbiology & Immunology, Oregon Health & Science University, Portland, Oregon, USA
| | - Alejandro Aballay
- Department of Molecular Microbiology & Immunology, Oregon Health & Science University, Portland, Oregon, USA.
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23
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Gutiérrez-Pérez P, Santillán EM, Lendl T, Wang J, Schrempf A, Steinacker TL, Asparuhova M, Brandstetter M, Haselbach D, Cochella L. miR-1 sustains muscle physiology by controlling V-ATPase complex assembly. SCIENCE ADVANCES 2021; 7:eabh1434. [PMID: 34652942 PMCID: PMC8519577 DOI: 10.1126/sciadv.abh1434] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Accepted: 08/23/2021] [Indexed: 05/13/2023]
Abstract
Muscle function requires unique structural and metabolic adaptations that can render muscle cells selectively vulnerable, with mutations in some ubiquitously expressed genes causing myopathies but sparing other tissues. We uncovered a muscle cell vulnerability by studying miR-1, a deeply conserved, muscle-specific microRNA whose ablation causes various muscle defects. Using Caenorhabditis elegans, we found that miR-1 represses multiple subunits of the ubiquitous vacuolar adenosine triphosphatase (V-ATPase) complex, which is essential for internal compartment acidification and metabolic signaling. V-ATPase subunits are predicted miR-1 targets in animals ranging from C. elegans to humans, and we experimentally validated this in Drosophila. Unexpectedly, up-regulation of V-ATPase subunits upon miR-1 deletion causes reduced V-ATPase function due to defects in complex assembly. These results reveal V-ATPase assembly as a conserved muscle cell vulnerability and support a previously unknown role for microRNAs in the regulation of protein complexes.
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Affiliation(s)
- Paula Gutiérrez-Pérez
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), 1030 Vienna, Austria
- Vienna BioCenter PhD Program, Doctoral School of the University of Vienna and Medical University of Vienna, 1030 Vienna, Austria
| | - Emilio M. Santillán
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), 1030 Vienna, Austria
- Vienna BioCenter PhD Program, Doctoral School of the University of Vienna and Medical University of Vienna, 1030 Vienna, Austria
| | - Thomas Lendl
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), 1030 Vienna, Austria
| | - Jingkui Wang
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), 1030 Vienna, Austria
| | - Anna Schrempf
- Research Center for Molecular Medicine of the Austrian Academy of Sciences, 1090 Vienna, Austria
| | | | - Mila Asparuhova
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), 1030 Vienna, Austria
| | - Marlene Brandstetter
- Electron Microscopy Facility, Vienna BioCenter Core Facilities GmbH, Vienna, Austria
| | - David Haselbach
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), 1030 Vienna, Austria
| | - Luisa Cochella
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), 1030 Vienna, Austria
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24
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Rapti G. A perspective on C. elegans neurodevelopment: from early visionaries to a booming neuroscience research. J Neurogenet 2021; 34:259-272. [PMID: 33446023 DOI: 10.1080/01677063.2020.1837799] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The formation of the nervous system and its striking complexity is a remarkable feat of development. C. elegans served as a unique model to dissect the molecular events in neurodevelopment, from its early visionaries to the current booming neuroscience community. Soon after being introduced as a model, C. elegans was mapped at the level of genes, cells, and synapses, providing the first metazoan with a complete cell lineage, sequenced genome, and connectome. Here, I summarize mechanisms underlying C. elegans neurodevelopment, from the generation and diversification of neural components to their navigation and connectivity. I point out recent noteworthy findings in the fields of glia biology, sex dimorphism and plasticity in neurodevelopment, highlighting how current research connects back to the pioneering studies by Brenner, Sulston and colleagues. Multifaceted investigations in model organisms, connecting genes to cell function and behavior, expand our mechanistic understanding of neurodevelopment while allowing us to formulate emerging questions for future discoveries.
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Affiliation(s)
- Georgia Rapti
- European Molecular Biology Laboratory, Unit of Developmental Biology, Heidelberg, Germany
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25
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Yuval O, Iosilevskii Y, Meledin A, Podbilewicz B, Shemesh T. Neuron tracing and quantitative analyses of dendritic architecture reveal symmetrical three-way-junctions and phenotypes of git-1 in C. elegans. PLoS Comput Biol 2021; 17:e1009185. [PMID: 34280180 PMCID: PMC8321406 DOI: 10.1371/journal.pcbi.1009185] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2020] [Revised: 07/29/2021] [Accepted: 06/15/2021] [Indexed: 11/18/2022] Open
Abstract
Complex dendritic trees are a distinctive feature of neurons. Alterations to dendritic morphology are associated with developmental, behavioral and neurodegenerative changes. The highly-arborized PVD neuron of C. elegans serves as a model to study dendritic patterning; however, quantitative, objective and automated analyses of PVD morphology are missing. Here, we present a method for neuronal feature extraction, based on deep-learning and fitting algorithms. The extracted neuronal architecture is represented by a database of structural elements for abstracted analysis. We obtain excellent automatic tracing of PVD trees and uncover that dendritic junctions are unevenly distributed. Surprisingly, these junctions are three-way-symmetrical on average, while dendritic processes are arranged orthogonally. We quantify the effect of mutation in git-1, a regulator of dendritic spine formation, on PVD morphology and discover a localized reduction in junctions. Our findings shed new light on PVD architecture, demonstrating the effectiveness of our objective analyses of dendritic morphology and suggest molecular control mechanisms. Nerve cells (neurons) collect input signals via branched cellular projections called dendrites. A major aspect of the study of neurons, dating back over a century, involves the characterization of neuronal shapes and of their dendritic processes. Here, we present an algorithmic approach for detection and classification of the tree-like dendrites of the PVD neuron in C. elegans worms. A key feature of our approach is to represent dendritic trees by a set of fundamental shapes, such as junctions and linear elements. By analyzing this dataset, we discovered several novel structural features. We have found that the junctions connecting branched dendrites have a three-way-symmetry, although the dendrites are arranged in a crosshatch pattern, and that the distribution of junctions varies across distinct sub-classes of the PVD’s dendritic tree. We further quantified subtle morphological effects due to mutation in the git-1 gene, a known regulator of dendritic spines. Our findings suggest molecular mechanisms for dendritic shape regulation and may help direct new avenues of research.
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Affiliation(s)
- Omer Yuval
- Faculty of Biology, Technion–Israel Institute of Technology, Haifa, Israel
- School of Computing, Faculty of Engineering and Physical Sciences, University of Leeds, Leeds, United Kingdom
| | - Yael Iosilevskii
- Faculty of Biology, Technion–Israel Institute of Technology, Haifa, Israel
| | - Anna Meledin
- Faculty of Biology, Technion–Israel Institute of Technology, Haifa, Israel
| | - Benjamin Podbilewicz
- Faculty of Biology, Technion–Israel Institute of Technology, Haifa, Israel
- * E-mail: (BP); (TS)
| | - Tom Shemesh
- Faculty of Biology, Technion–Israel Institute of Technology, Haifa, Israel
- * E-mail: (BP); (TS)
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26
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Tang LTH, Trivedi M, Freund J, Salazar CJ, Rahman M, Ramirez-Suarez NJ, Lee G, Wang Y, Grant BD, Bülow HE. The CATP-8/P5A-type ATPase functions in multiple pathways during neuronal patterning. PLoS Genet 2021; 17:e1009475. [PMID: 34197450 PMCID: PMC8279360 DOI: 10.1371/journal.pgen.1009475] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2021] [Revised: 07/14/2021] [Accepted: 06/10/2021] [Indexed: 11/18/2022] Open
Abstract
The assembly of neuronal circuits involves the migrations of neurons from their place of birth to their final location in the nervous system, as well as the coordinated growth and patterning of axons and dendrites. In screens for genes required for patterning of the nervous system, we identified the catp-8/P5A-ATPase as an important regulator of neural patterning. P5A-ATPases are part of the P-type ATPases, a family of proteins known to serve a conserved function as transporters of ions, lipids and polyamines in unicellular eukaryotes, plants, and humans. While the function of many P-type ATPases is relatively well understood, the function of P5A-ATPases in metazoans remained elusive. We show here, that the Caenorhabditis elegans ortholog catp-8/P5A-ATPase is required for defined aspects of nervous system development. Specifically, the catp-8/P5A-ATPase serves functions in shaping the elaborately sculpted dendritic trees of somatosensory PVD neurons. Moreover, catp-8/P5A-ATPase is required for axonal guidance and repulsion at the midline, as well as embryonic and postembryonic neuronal migrations. Interestingly, not all axons at the midline require catp-8/P5A-ATPase, although the axons run in the same fascicles and navigate the same space. Similarly, not all neuronal migrations require catp-8/P5A-ATPase. A CATP-8/P5A-ATPase reporter is localized to the ER in most, if not all, tissues and catp-8/P5A-ATPase can function both cell-autonomously and non-autonomously to regulate neuronal development. Genetic analyses establish that catp-8/P5A-ATPase can function in multiple pathways, including the Menorin pathway, previously shown to control dendritic patterning in PVD, and Wnt signaling, which functions to control neuronal migrations. Lastly, we show that catp-8/P5A-ATPase is required for localizing select transmembrane proteins necessary for dendrite morphogenesis. Collectively, our studies suggest that catp-8/P5A-ATPase serves diverse, yet specific, roles in different genetic pathways and may be involved in the regulation or localization of transmembrane and secreted proteins to specific subcellular compartments.
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Affiliation(s)
- Leo T. H. Tang
- Department of Genetics Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Meera Trivedi
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Jenna Freund
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Christopher J. Salazar
- Department of Genetics Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Maisha Rahman
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Nelson J. Ramirez-Suarez
- Department of Genetics Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Garrett Lee
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Yu Wang
- Department of Molecular Biology & Biochemistry, Rutgers Center for Lipid Research, Rutgers University, Piscataway, New Jersey, United States of America
| | - Barth D. Grant
- Department of Molecular Biology & Biochemistry, Rutgers Center for Lipid Research, Rutgers University, Piscataway, New Jersey, United States of America
| | - Hannes E. Bülow
- Department of Genetics Albert Einstein College of Medicine, Bronx, New York, United States of America
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, New York, United States of America
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27
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Emmons SW, Yemini E, Zimmer M. Methods for analyzing neuronal structure and activity in Caenorhabditis elegans. Genetics 2021; 218:6303616. [PMID: 34151952 DOI: 10.1093/genetics/iyab072] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Accepted: 04/20/2021] [Indexed: 11/12/2022] Open
Abstract
The model research animal Caenorhabditis elegans has unique properties making it particularly advantageous for studies of the nervous system. The nervous system is composed of a stereotyped complement of neurons connected in a consistent manner. Here, we describe methods for studying nervous system structure and function. The transparency of the animal makes it possible to visualize and identify neurons in living animals with fluorescent probes. These methods have been recently enhanced for the efficient use of neuron-specific reporter genes. Because of its simple structure, for a number of years, C. elegans has been at the forefront of connectomic studies defining synaptic connectivity by electron microscopy. This field is burgeoning with new, more powerful techniques, and recommended up-to-date methods are here described that encourage the possibility of new work in C. elegans. Fluorescent probes for single synapses and synaptic connections have allowed verification of the EM reconstructions and for experimental approaches to synapse formation. Advances in microscopy and in fluorescent reporters sensitive to Ca2+ levels have opened the way to observing activity within single neurons across the entire nervous system.
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Affiliation(s)
- Scott W Emmons
- Department of Genetics and Dominick Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY 1041, USA
| | - Eviatar Yemini
- Department of Biological Sciences, Howard Hughes Medical Institute, Columbia University, New York, NY 10027, USA
| | - Manuel Zimmer
- Department of Neuroscience and Developmental Biology, University of Vienna, Vienna 1090, Austria and.,Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Vienna 1030, Austria
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28
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Tavosanis G. Dendrite enlightenment. Curr Opin Neurobiol 2021; 69:222-230. [PMID: 34134010 DOI: 10.1016/j.conb.2021.05.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 05/04/2021] [Accepted: 05/05/2021] [Indexed: 12/18/2022]
Abstract
Neuronal dendrites acquire complex morphologies during development. These are not just the product of cell-intrinsic developmental programs; rather they are defined in close interaction with the cellular environment. Thus, to understand the molecular cascades that yield appropriate morphologies, it is essential to investigate them in vivo, in the actual complex tissue environment encountered by the differentiating neuron in the developing animal. Particularly, genetic approaches have pointed to factors controlling dendrite differentiation in vivo. These suggest that localized and transient molecular cascades might underlie the formation and stabilization of dendrite branches with neuron type-specific characteristics. Here, I highlight the need for studies of neuronal dendrite differentiation in the animal, the challenges provided by such an approach, and the promising pathways that have recently opened.
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Affiliation(s)
- Gaia Tavosanis
- German Center for Neurodegenerative Diseases (DZNE), Venusberg-Campus 1/99, Bonn, 53127, Germany; LIMES Institute, University of Bonn, Carl-Troll-Str. 3, Bonn, 53115, Germany.
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29
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Yin C, Peterman E, Rasmussen JP, Parrish JZ. Transparent Touch: Insights From Model Systems on Epidermal Control of Somatosensory Innervation. Front Cell Neurosci 2021; 15:680345. [PMID: 34135734 PMCID: PMC8200473 DOI: 10.3389/fncel.2021.680345] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2021] [Accepted: 04/28/2021] [Indexed: 12/28/2022] Open
Abstract
Somatosensory neurons (SSNs) densely innervate our largest organ, the skin, and shape our experience of the world, mediating responses to sensory stimuli including touch, pressure, and temperature. Historically, epidermal contributions to somatosensation, including roles in shaping innervation patterns and responses to sensory stimuli, have been understudied. However, recent work demonstrates that epidermal signals dictate patterns of SSN skin innervation through a variety of mechanisms including targeting afferents to the epidermis, providing instructive cues for branching morphogenesis, growth control and structural stability of neurites, and facilitating neurite-neurite interactions. Here, we focus onstudies conducted in worms (Caenorhabditis elegans), fruit flies (Drosophila melanogaster), and zebrafish (Danio rerio): prominent model systems in which anatomical and genetic analyses have defined fundamental principles by which epidermal cells govern SSN development.
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Affiliation(s)
| | | | | | - Jay Z. Parrish
- Department of Biology, University of Washington, Seattle, WA, United States
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30
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Kaur S, Aballay A. G-Protein-Coupled Receptor SRBC-48 Protects against Dendrite Degeneration and Reduced Longevity Due to Infection. Cell Rep 2021; 31:107662. [PMID: 32433971 DOI: 10.1016/j.celrep.2020.107662] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Revised: 03/06/2020] [Accepted: 04/28/2020] [Indexed: 02/07/2023] Open
Abstract
Increasing evidence suggests that deficient immune modulation and microbial infections underline neurodegeneration, but the mechanisms remain obscure. Here, we show that the G-protein-coupled receptor (GPCR) SRBC-48, which belongs to the class BC serpentine receptors, has a protective role in Caenorhabditis elegans dendrite degeneration caused by Pseudomonas aeruginosa infection. Our results indicate that SRBC-48 functions in a cell-autonomous manner in AWC neurons to protect against infection-associated dendrite degeneration. The absence of SRBC-48 results in a reduced lifespan caused by a pathogen infection early in life that induces dendrite degeneration. The decreased longevity in animals deficient in SRBC-48 is due to uncontrolled activation of immune genes, particularly those regulated by the FOXO family transcription factor DAF-16 that is part of the insulin/insulin-like growth factor (IGF)-1 receptor homolog DAF-2. These results reveal how an infection early in life can not only induce dendrite degeneration but also reduce lifespan.
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Affiliation(s)
- Supender Kaur
- Department of Molecular Microbiology and Immunology, Oregon Health & Science University, Portland, OR 97239, USA
| | - Alejandro Aballay
- Department of Molecular Microbiology and Immunology, Oregon Health & Science University, Portland, OR 97239, USA.
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31
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Abstract
Establishment of neural circuits requires reproducible and precise interactions between growing axons, dendrites and their tissue environment. Cell adhesion molecules and guidance factors are involved in the process, but how specificity is achieved remains poorly understood. Glycans are the third major class of biopolymers besides nucleic acids and proteins, and are usually covalently linked to proteins to form glycoconjugates. Common to most glycans is an extraordinary level of molecular diversity, making them attractive candidates to contribute specificity during neural development. Indeed, many genes important for neural development encode glycoproteins, or enzymes involved in synthesizing or modifying glycans. Glycoconjugates are classified based on both the types of glycans and type of attachment that link them to proteins. Here I discuss progress in understanding the function of glycans, glycan modifications and glycoconjugates during neural development in Caenorhabditis elegans. I will also highlight relevance to human disease and known roles of glycoconjugates in regeneration.
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Affiliation(s)
- Hannes E Bülow
- Department of Genetics, Albert Einstein College of Medicine, Bronx, NY, United States; Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY, United States.
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32
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Abstract
The nematode Caenorhabditis elegans nociceptive PVD neurons have highly ordered dendritic branches, making this an ideal model to study the development and organization of dendrites. A ser-2-promoter-driven GFP reporter line wyIs592[ser-2prom-3p::myr-GFP] provides a comprehensive visualization of PVD anatomy. Here, we describe the detailed procedures for imaging a PVD neuron using wyIs592 at late L4 larval stage in vivo by confocal microscopy. This protocol can also be applied to imaging other cells in C. elegans. For complete details on the use and execution of this protocol, please refer to Feng et al. (2020). Protocol for fluorescence imaging in C. elegans Worm strain cultivation for stress-sensitive neurons Acquiring and assembling pictures for a large neuron with highly elaborate dendrites
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33
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Laranjeiro R, Harinath G, Pollard AK, Gaffney CJ, Deane CS, Vanapalli SA, Etheridge T, Szewczyk NJ, Driscoll M. Spaceflight affects neuronal morphology and alters transcellular degradation of neuronal debris in adult Caenorhabditis elegans. iScience 2021; 24:102105. [PMID: 33659873 PMCID: PMC7890410 DOI: 10.1016/j.isci.2021.102105] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Revised: 12/17/2020] [Accepted: 01/21/2021] [Indexed: 12/21/2022] Open
Abstract
Extended space travel is a goal of government space agencies and private companies. However, spaceflight poses risks to human health, and the effects on the nervous system have to be better characterized. Here, we exploited the unique experimental advantages of the nematode Caenorhabditis elegans to explore how spaceflight affects adult neurons in vivo. We found that animals that lived 5 days of adulthood on the International Space Station exhibited hyperbranching in PVD and touch receptor neurons. We also found that, in the presence of a neuronal proteotoxic stress, spaceflight promotes a remarkable accumulation of neuronal-derived waste in the surrounding tissues, suggesting an impaired transcellular degradation of debris released from neurons. Our data reveal that spaceflight can significantly affect adult neuronal morphology and clearance of neuronal trash, highlighting the need to carefully assess the risks of long-duration spaceflight on the nervous system and to develop adequate countermeasures for safe space exploration.
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Affiliation(s)
- Ricardo Laranjeiro
- Department of Molecular Biology and Biochemistry, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
| | - Girish Harinath
- Department of Molecular Biology and Biochemistry, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
| | - Amelia K. Pollard
- MRC Versus Arthritis Centre for Musculoskeletal Ageing Research and NIHR Nottingham BRC, University of Nottingham, Medical School Royal Derby Hospital, Derby, DE22 3DT, UK
| | - Christopher J. Gaffney
- Sport and Health Sciences, University of Exeter, Exeter, EX1 2LU, UK
- Lancaster Medical School, Health Innovation One, Lancaster University, Lancaster, LA1 4AT, UK
| | - Colleen S. Deane
- Sport and Health Sciences, University of Exeter, Exeter, EX1 2LU, UK
| | - Siva A. Vanapalli
- Department of Chemical Engineering, Texas Tech University, Lubbock, TX 79409, USA
| | - Timothy Etheridge
- Sport and Health Sciences, University of Exeter, Exeter, EX1 2LU, UK
| | - Nathaniel J. Szewczyk
- MRC Versus Arthritis Centre for Musculoskeletal Ageing Research and NIHR Nottingham BRC, University of Nottingham, Medical School Royal Derby Hospital, Derby, DE22 3DT, UK
- Ohio Musculoskeletal and Neurologic Institute and Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, Ohio University, Athens, OH 45701, USA
| | - Monica Driscoll
- Department of Molecular Biology and Biochemistry, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
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34
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Ma Y, Xie J, Wijaya CS, Xu S. From wound response to repair - lessons from C. elegans. CELL REGENERATION 2021; 10:5. [PMID: 33532882 PMCID: PMC7855202 DOI: 10.1186/s13619-020-00067-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Accepted: 10/31/2020] [Indexed: 02/07/2023]
Abstract
As a result of evolution, the ability to repair wounds allows organisms to combat environment insults. Although the general process of wound healing at the tissue level has been described for decades, the detailed molecular mechanisms regarding the early wound response and rapid wound repair at the cellular level remain little understood. Caenorhabditis elegans is a model organism widely used in the field of development, neuroscience, programmed cell death etc. The nematode skin is composed of a large epidermis associated with a transparent extracellular cuticle, which likely has a robust capacity for epidermal repair. Yet, until the last decades, relatively few studies had directly analyzed the wound response and repair process. Here we review recent findings in how C. elegans epidermis responds to wounding and initiates early actin-polymerization-based wound closure as well as later membrane repair. We also discussed some remained outstanding questions for future study.
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Affiliation(s)
- Yicong Ma
- The Zhejiang University-University of Edinburgh Institute and Department of Cardiology of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, 310058, China
| | - Jing Xie
- The Zhejiang University-University of Edinburgh Institute and Department of Cardiology of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, 310058, China
| | - Chandra Sugiarto Wijaya
- Center for Stem Cell and Regenerative Medicine, School of Basic Medical Sciences, Zhejiang University, Hangzhou, 310058, China
| | - Suhong Xu
- The Zhejiang University-University of Edinburgh Institute and Department of Cardiology of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, 310058, China. .,Center for Stem Cell and Regenerative Medicine, School of Basic Medical Sciences, Zhejiang University, Hangzhou, 310058, China.
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35
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Abstract
During multicellular organism development, complex structures are sculpted to form organs and tissues, which are maintained throughout adulthood. Many of these processes require cells to fuse with one another, or with themselves. These plasma membrane fusions merge endoplasmic cellular content across external, exoplasmic, space. In the nematode Caenorhabditis elegans, such cell fusions serve as a unique sculpting force, involved in the embryonic morphogenesis of the skin-like multinuclear hypodermal cells, but also in refining delicate structures, such as valve openings and the tip of the tail. During post-embryonic development, plasma membrane fusions continue to shape complex neuron structures and organs such as the vulva, while during adulthood fusion participates in cell and tissue repair. These processes rely on two fusion proteins (fusogens): EFF-1 and AFF-1, which are part of a broader family of structurally related membrane fusion proteins, encompassing sexual reproduction, viral infection, and tissue remodeling. The established capabilities of these exoplasmic fusogens are further expanded by new findings involving EFF-1 and AFF-1 in endocytic vesicle fission and phagosome sealing. Tight regulation by cell-autonomous and non-cell autonomous mechanisms orchestrates these diverse cell fusions at the correct place and time-these processes and their significance are discussed in this review.
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36
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Furusawa K, Emoto K. Scrap and Build for Functional Neural Circuits: Spatiotemporal Regulation of Dendrite Degeneration and Regeneration in Neural Development and Disease. Front Cell Neurosci 2021; 14:613320. [PMID: 33505249 PMCID: PMC7829185 DOI: 10.3389/fncel.2020.613320] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Accepted: 12/04/2020] [Indexed: 01/01/2023] Open
Abstract
Dendrites are cellular structures essential for the integration of neuronal information. These elegant but complex structures are highly patterned across the nervous system but vary tremendously in their size and fine architecture, each designed to best serve specific computations within their networks. Recent in vivo imaging studies reveal that the development of mature dendrite arbors in many cases involves extensive remodeling achieved through a precisely orchestrated interplay of growth, degeneration, and regeneration of dendritic branches. Both degeneration and regeneration of dendritic branches involve precise spatiotemporal regulation for the proper wiring of functional networks. In particular, dendrite degeneration must be targeted in a compartmentalized manner to avoid neuronal death. Dysregulation of these developmental processes, in particular dendrite degeneration, is associated with certain types of pathology, injury, and aging. In this article, we review recent progress in our understanding of dendrite degeneration and regeneration, focusing on molecular and cellular mechanisms underlying spatiotemporal control of dendrite remodeling in neural development. We further discuss how developmental dendrite degeneration and regeneration are molecularly and functionally related to dendrite remodeling in pathology, disease, and aging.
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Affiliation(s)
- Kotaro Furusawa
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Kazuo Emoto
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan.,International Research Center for Neurointelligence (WPI-IRCN), The University of Tokyo, Tokyo, Japan
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37
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Modular transient nanoclustering of activated β2-adrenergic receptors revealed by single-molecule tracking of conformation-specific nanobodies. Proc Natl Acad Sci U S A 2020; 117:30476-30487. [PMID: 33214152 DOI: 10.1073/pnas.2007443117] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
None of the current superresolution microscopy techniques can reliably image the changes in endogenous protein nanoclustering dynamics associated with specific conformations in live cells. Single-domain nanobodies have been invaluable tools to isolate defined conformational states of proteins, and we reasoned that expressing these nanobodies coupled to single-molecule imaging-amenable tags could allow superresolution analysis of endogenous proteins in discrete conformational states. Here, we used anti-GFP nanobodies tagged with photoconvertible mEos expressed as intrabodies, as a proof-of-concept to perform single-particle tracking on a range of GFP proteins expressed in live cells, neurons, and small organisms. We next expressed highly specialized nanobodies that target conformation-specific endogenous β2-adrenoreceptor (β2-AR) in neurosecretory cells, unveiling real-time mobility behaviors of activated and inactivated endogenous conformers during agonist treatment in living cells. We showed that activated β2-AR (Nb80) is highly immobile and organized in nanoclusters. The Gαs-GPCR complex detected with Nb37 displayed higher mobility with surprisingly similar nanoclustering dynamics to that of Nb80. Activated conformers are highly sensitive to dynamin inhibition, suggesting selective targeting for endocytosis. Inactivated β2-AR (Nb60) molecules are also largely immobile but relatively less sensitive to endocytic blockade. Expression of single-domain nanobodies therefore provides a unique opportunity to capture highly transient changes in the dynamic nanoscale organization of endogenous proteins.
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38
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Saberi-Bosari S, Flores KB, San-Miguel A. Deep learning-enabled analysis reveals distinct neuronal phenotypes induced by aging and cold-shock. BMC Biol 2020; 18:130. [PMID: 32967665 PMCID: PMC7510121 DOI: 10.1186/s12915-020-00861-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Accepted: 09/01/2020] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND Access to quantitative information is crucial to obtain a deeper understanding of biological systems. In addition to being low-throughput, traditional image-based analysis is mostly limited to error-prone qualitative or semi-quantitative assessment of phenotypes, particularly for complex subcellular morphologies. The PVD neuron in Caenorhabditis elegans, which is responsible for harsh touch and thermosensation, undergoes structural degeneration as nematodes age characterized by the appearance of dendritic protrusions. Analysis of these neurodegenerative patterns is labor-intensive and limited to qualitative assessment. RESULTS In this work, we apply deep learning to perform quantitative image-based analysis of complex neurodegeneration patterns exhibited by the PVD neuron in C. elegans. We apply a convolutional neural network algorithm (Mask R-CNN) to identify neurodegenerative subcellular protrusions that appear after cold-shock or as a result of aging. A multiparametric phenotypic profile captures the unique morphological changes induced by each perturbation. We identify that acute cold-shock-induced neurodegeneration is reversible and depends on rearing temperature and, importantly, that aging and cold-shock induce distinct neuronal beading patterns. CONCLUSION The results of this work indicate that implementing deep learning for challenging image segmentation of PVD neurodegeneration enables quantitatively tracking subtle morphological changes in an unbiased manner. This analysis revealed that distinct patterns of morphological alteration are induced by aging and cold-shock, suggesting different mechanisms at play. This approach can be used to identify the molecular components involved in orchestrating neurodegeneration and to characterize the effect of other stressors on PVD degeneration.
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Affiliation(s)
- Sahand Saberi-Bosari
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC, 27695, USA
| | - Kevin B Flores
- Department of Mathematics, North Carolina State University, Raleigh, NC, 27695, USA
| | - Adriana San-Miguel
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC, 27695, USA.
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39
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Fusogen-mediated neuron-neuron fusion disrupts neural circuit connectivity and alters animal behavior. Proc Natl Acad Sci U S A 2020; 117:23054-23065. [PMID: 32855296 PMCID: PMC7502713 DOI: 10.1073/pnas.1919063117] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Ramón y Cajal’s neuron doctrine, which states that neurons are individual cells that do not share any membrane or cytoplasmic continuity between them, has underpinned our view of modern neuroscience. However, there is considerable evidence that fusogens, specialized proteins essential and sufficient for the fusion of cells in other tissues, are expressed in the nervous system of several species in response to viral infection, stress conditions, and neurological disease. By manipulating the expression of fusogens in the chemosensory neurons of Caenorhabditis elegans, our results provide conclusive evidence that deregulation of fusogen expression causes neuronal fusion and can have deleterious effects on neural circuitry and behavioral outputs, revealing a possible novel underlying cause of neurological disorders. The 100-y-old neuron doctrine from Ramón y Cajal states that neurons are individual cells, rejecting the process of cell−cell fusion in the normal development and function of the nervous system. However, fusogens—specialized molecules essential and sufficient for the fusion of cells—are expressed in the nervous system of different species under conditions of viral infection, stress, or disease. Despite these findings, whether the expression of fusogens in neurons leads to cell−cell fusion, and, if so, whether this affects neuronal fate, function, and animal behavior, has not been explored. Here, using Caenorhabditis elegans chemosensory neurons as a model system, we provide proof-of-principle that aberrant expression of fusogens in neurons results in neuron−neuron fusion and behavioral impairments. We demonstrate that fusion between chemoattractive neurons does not affect the response to odorants, whereas fusion between chemoattractive and chemorepulsive neurons compromises chemosensation. Moreover, we provide evidence that fused neurons are viable and retain their original specific neuronal fate markers. Finally, analysis of calcium transients reveals that fused neurons become electrically coupled, thereby compromising neural circuit connectivity. Thus, we propose that aberrant expression of fusogens in the nervous system disrupts neuronal individuality, which, in turn, leads to a change in neural circuit connectivity and disruption of normal behavior. Our results expose a previously uncharacterized basis of circuit malfunction, and a possible underlying cause of neurological diseases.
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40
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Androwski RJ, Asad N, Wood JG, Hofer A, Locke S, Smith CM, Rose B, Schroeder NE. Mutually exclusive dendritic arbors in C. elegans neurons share a common architecture and convergent molecular cues. PLoS Genet 2020; 16:e1009029. [PMID: 32997655 PMCID: PMC7549815 DOI: 10.1371/journal.pgen.1009029] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Revised: 10/12/2020] [Accepted: 08/05/2020] [Indexed: 12/31/2022] Open
Abstract
Stress-induced changes to the dendritic architecture of neurons have been demonstrated in numerous mammalian and invertebrate systems. Remodeling of dendrites varies tremendously among neuron types. During the stress-induced dauer stage of Caenorhabditis elegans, the IL2 neurons arborize to cover the anterior body wall. In contrast, the FLP neurons arborize to cover an identical receptive field during reproductive development. Using time-course imaging, we show that branching between these two neuron types is highly coordinated. Furthermore, we find that the IL2 and FLP arbors have a similar dendritic architecture and use an identical downstream effector complex to control branching; however, regulation of this complex differs between stress-induced IL2 branching and FLP branching during reproductive development. We demonstrate that the unfolded protein response (UPR) sensor IRE-1, required for localization of the complex in FLP branching, is dispensable for IL2 branching at standard cultivation temperatures. Exposure of ire-1 mutants to elevated temperatures results in defective IL2 branching, thereby demonstrating a previously unknown genotype by environment interaction within the UPR. We find that the FOXO homolog, DAF-16, is required cell-autonomously to control arborization during stress-induced arborization. Likewise, several aspects of the dauer formation pathway are necessary for the neuron to remodel, including the phosphatase PTEN/DAF-18 and Cytochrome P450/DAF-9. Finally, we find that the TOR associated protein, RAPTOR/DAF-15 regulates mutually exclusive branching of the IL2 and FLP dendrites. DAF-15 promotes IL2 branching during dauer and inhibits precocious FLP growth. Together, our results shed light on molecular processes that regulate stress-mediated remodeling of dendrites across neuron classes.
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Affiliation(s)
- Rebecca J. Androwski
- Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
| | - Nadeem Asad
- Department of Crop Sciences, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
| | - Janet G. Wood
- Department of Crop Sciences, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
| | - Allison Hofer
- Department of Crop Sciences, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
| | - Steven Locke
- Department of Crop Sciences, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
| | - Cassandra M. Smith
- Department of Crop Sciences, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
| | - Becky Rose
- Department of Crop Sciences, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
| | - Nathan E. Schroeder
- Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
- Department of Crop Sciences, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
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41
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Actin Polymerization and ESCRT Trigger Recruitment of the Fusogens Syntaxin-2 and EFF-1 to Promote Membrane Repair in C. elegans. Dev Cell 2020; 54:624-638.e5. [DOI: 10.1016/j.devcel.2020.06.027] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Revised: 05/08/2020] [Accepted: 06/19/2020] [Indexed: 12/20/2022]
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42
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Hsu HW, Liao CP, Chiang YC, Syu RT, Pan CL. Caenorhabditis elegans Flamingo FMI-1 controls dendrite self-avoidance through F-actin assembly. Development 2020; 147:dev179168. [PMID: 32631831 DOI: 10.1242/dev.179168] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Accepted: 06/29/2020] [Indexed: 12/11/2022]
Abstract
Self-avoidance is a conserved mechanism that prevents crossover between sister dendrites from the same neuron, ensuring proper functioning of the neuronal circuits. Several adhesion molecules are known to be important for dendrite self-avoidance, but the underlying molecular mechanisms are incompletely defined. Here, we show that FMI-1/Flamingo, an atypical cadherin, is required autonomously for self-avoidance in the multidendritic PVD neuron of Caenorhabditis elegans The fmi-1 mutant shows increased crossover between sister PVD dendrites. Our genetic analysis suggests that FMI-1 promotes transient F-actin assembly at the tips of contacting sister dendrites to facilitate their efficient retraction during self-avoidance events, probably by interacting with WSP-1/N-WASP. Mutations of vang-1, which encodes the planar cell polarity protein Vangl2 previously shown to inhibit F-actin assembly, suppress self-avoidance defects of the fmi-1 mutant. FMI-1 downregulates VANG-1 levels probably through forming protein complexes. Our study identifies molecular links between Flamingo and the F-actin cytoskeleton that facilitate efficient dendrite self-avoidance.
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Affiliation(s)
- Hao-Wei Hsu
- Institute of Molecular Medicine and Center of Precision Medicine, College of Medicine, National Taiwan University, Taipei 10002, Taiwan
| | - Chien-Po Liao
- Institute of Molecular Medicine and Center of Precision Medicine, College of Medicine, National Taiwan University, Taipei 10002, Taiwan
| | - Yueh-Chen Chiang
- Institute of Molecular Medicine and Center of Precision Medicine, College of Medicine, National Taiwan University, Taipei 10002, Taiwan
| | - Ru-Ting Syu
- Institute of Molecular Medicine and Center of Precision Medicine, College of Medicine, National Taiwan University, Taipei 10002, Taiwan
| | - Chun-Liang Pan
- Institute of Molecular Medicine and Center of Precision Medicine, College of Medicine, National Taiwan University, Taipei 10002, Taiwan
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Jean P, Anttonen T, Michanski S, de Diego AMG, Steyer AM, Neef A, Oestreicher D, Kroll J, Nardis C, Pangršič T, Möbius W, Ashmore J, Wichmann C, Moser T. Macromolecular and electrical coupling between inner hair cells in the rodent cochlea. Nat Commun 2020; 11:3208. [PMID: 32587250 PMCID: PMC7316811 DOI: 10.1038/s41467-020-17003-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Accepted: 05/30/2020] [Indexed: 11/10/2022] Open
Abstract
Inner hair cells (IHCs) are the primary receptors for hearing. They are housed in the cochlea and convey sound information to the brain via synapses with the auditory nerve. IHCs have been thought to be electrically and metabolically independent from each other. We report that, upon developmental maturation, in mice 30% of the IHCs are electrochemically coupled in 'mini-syncytia'. This coupling permits transfer of fluorescently-labeled metabolites and macromolecular tracers. The membrane capacitance, Ca2+-current, and resting current increase with the number of dye-coupled IHCs. Dual voltage-clamp experiments substantiate low resistance electrical coupling. Pharmacology and tracer permeability rule out coupling by gap junctions and purinoceptors. 3D electron microscopy indicates instead that IHCs are coupled by membrane fusion sites. Consequently, depolarization of one IHC triggers presynaptic Ca2+-influx at active zones in the entire mini-syncytium. Based on our findings and modeling, we propose that IHC-mini-syncytia enhance sensitivity and reliability of cochlear sound encoding.
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Affiliation(s)
- Philippe Jean
- Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, Göttingen, Germany
- Collaborative Research Center 889, University of Göttingen, Göttingen, Germany
- Auditory Neuroscience Group, Max Planck Institute of Experimental Medicine, Göttingen, Germany
- Göttingen Graduate School for Neurosciences and Molecular Biosciences, University of Göttingen, Göttingen, Germany
| | - Tommi Anttonen
- Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, Göttingen, Germany
- Collaborative Research Center 889, University of Göttingen, Göttingen, Germany
- Synaptic Nanophysiology Group, Max Planck Institute of Biophysical Chemistry, Göttingen, Germany
| | - Susann Michanski
- Collaborative Research Center 889, University of Göttingen, Göttingen, Germany
- Molecular Architecture of Synapses Group, Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, Göttingen, Germany
- Center for Biostructural Imaging of Neurodegeneration, Göttingen, Germany
| | - Antonio M G de Diego
- UCL Ear Institute and Department of Neuroscience, Physiology and Pharmacology, University College London, London, UK
| | - Anna M Steyer
- Electron Microscopy Core Unit, Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
- Center for Nanoscale Microscopy and Molecular Physiology of the Brain, University of Göttingen, Göttingen, Germany
| | - Andreas Neef
- Neurophysics laboratory, Campus Institute for Dynamics of Biological Networks, University of Göttingen, Göttingen, Germany
| | - David Oestreicher
- Experimental Otology Group, Institute for Auditory Neuroscience, InnerEarLab, and Department of Otolaryngology, University Medical Center Göttingen, Göttingen, Germany
| | - Jana Kroll
- Collaborative Research Center 889, University of Göttingen, Göttingen, Germany
- Göttingen Graduate School for Neurosciences and Molecular Biosciences, University of Göttingen, Göttingen, Germany
- Molecular Architecture of Synapses Group, Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, Göttingen, Germany
- Center for Biostructural Imaging of Neurodegeneration, Göttingen, Germany
| | - Christos Nardis
- Electron Microscopy Core Unit, Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
- Center for Nanoscale Microscopy and Molecular Physiology of the Brain, University of Göttingen, Göttingen, Germany
| | - Tina Pangršič
- Collaborative Research Center 889, University of Göttingen, Göttingen, Germany
- Experimental Otology Group, Institute for Auditory Neuroscience, InnerEarLab, and Department of Otolaryngology, University Medical Center Göttingen, Göttingen, Germany
| | - Wiebke Möbius
- Electron Microscopy Core Unit, Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
- Center for Nanoscale Microscopy and Molecular Physiology of the Brain, University of Göttingen, Göttingen, Germany
| | - Jonathan Ashmore
- UCL Ear Institute and Department of Neuroscience, Physiology and Pharmacology, University College London, London, UK
| | - Carolin Wichmann
- Collaborative Research Center 889, University of Göttingen, Göttingen, Germany.
- Molecular Architecture of Synapses Group, Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, Göttingen, Germany.
- Center for Biostructural Imaging of Neurodegeneration, Göttingen, Germany.
- Multiscale Bioimaging Cluster of Excellence (MBExC), University of Göttingen, Göttingen, Germany.
| | - Tobias Moser
- Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, Göttingen, Germany.
- Collaborative Research Center 889, University of Göttingen, Göttingen, Germany.
- Auditory Neuroscience Group, Max Planck Institute of Experimental Medicine, Göttingen, Germany.
- Synaptic Nanophysiology Group, Max Planck Institute of Biophysical Chemistry, Göttingen, Germany.
- Center for Nanoscale Microscopy and Molecular Physiology of the Brain, University of Göttingen, Göttingen, Germany.
- Multiscale Bioimaging Cluster of Excellence (MBExC), University of Göttingen, Göttingen, Germany.
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A Caenorhabditis elegans Model for Integrating the Functions of Neuropsychiatric Risk Genes Identifies Components Required for Normal Dendritic Morphology. G3-GENES GENOMES GENETICS 2020; 10:1617-1628. [PMID: 32132169 PMCID: PMC7202017 DOI: 10.1534/g3.119.400925] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Analysis of patient-derived DNA samples has identified hundreds of variants that are likely involved in neuropsychiatric diseases such as autism spectrum disorder (ASD) and schizophrenia (SCZ). While these studies couple behavioral phenotypes to individual genotypes, the number and diversity of candidate genes implicated in these disorders highlights the fact that the mechanistic underpinnings of these disorders are largely unknown. Here, we describe a RNAi-based screening platform that uses C. elegans to screen candidate neuropsychiatric risk genes (NRGs) for roles in controlling dendritic arborization. To benchmark this approach, we queried published lists of NRGs whose variants in ASD and SCZ are predicted to result in complete or partial loss of gene function. We found that a significant fraction (>16%) of these candidate NRGs are essential for dendritic development. Furthermore, these gene sets are enriched for dendritic arbor phenotypes (>14 fold) when compared to control RNAi datasets of over 500 human orthologs. The diversity of PVD structural abnormalities observed in these assays suggests that the functions of diverse NRGs (encoding transcription factors, chromatin remodelers, molecular chaperones and cytoskeleton-related proteins) converge to regulate neuronal morphology and that individual NRGs may play distinct roles in dendritic branching. We also demonstrate that the experimental value of this platform by providing additional insights into the molecular frameworks of candidate NRGs. Specifically, we show that ANK2/UNC-44 function is directly integrated with known regulators of dendritic arborization and suggest that altering the dosage of ARID1B/LET-526 expression during development affects neuronal morphology without diminishing aspects of cell fate specification.
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How Caenorhabditis elegans Senses Mechanical Stress, Temperature, and Other Physical Stimuli. Genetics 2019; 212:25-51. [PMID: 31053616 PMCID: PMC6499529 DOI: 10.1534/genetics.118.300241] [Citation(s) in RCA: 66] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Accepted: 03/04/2019] [Indexed: 12/30/2022] Open
Abstract
Caenorhabditis elegans lives in a complex habitat in which they routinely experience large fluctuations in temperature, and encounter physical obstacles that vary in size and composition. Their habitat is shared by other nematodes, by beneficial and harmful bacteria, and nematode-trapping fungi. Not surprisingly, these nematodes can detect and discriminate among diverse environmental cues, and exhibit sensory-evoked behaviors that are readily quantifiable in the laboratory at high resolution. Their ability to perform these behaviors depends on <100 sensory neurons, and this compact sensory nervous system together with powerful molecular genetic tools has allowed individual neuron types to be linked to specific sensory responses. Here, we describe the sensory neurons and molecules that enable C. elegans to sense and respond to physical stimuli. We focus primarily on the pathways that allow sensation of mechanical and thermal stimuli, and briefly consider this animal’s ability to sense magnetic and electrical fields, light, and relative humidity. As the study of sensory transduction is critically dependent upon the techniques for stimulus delivery, we also include a section on appropriate laboratory methods for such studies. This chapter summarizes current knowledge about the sensitivity and response dynamics of individual classes of C. elegans mechano- and thermosensory neurons from in vivo calcium imaging and whole-cell patch-clamp electrophysiology studies. We also describe the roles of conserved molecules and signaling pathways in mediating the remarkably sensitive responses of these nematodes to mechanical and thermal cues. These studies have shown that the protein partners that form mechanotransduction channels are drawn from multiple superfamilies of ion channel proteins, and that signal transduction pathways responsible for temperature sensing in C. elegans share many features with those responsible for phototransduction in vertebrates.
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46
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E L, Zhou T, Koh S, Chuang M, Sharma R, Pujol N, Chisholm AD, Eroglu C, Matsunami H, Yan D. An Antimicrobial Peptide and Its Neuronal Receptor Regulate Dendrite Degeneration in Aging and Infection. Neuron 2019; 97:125-138.e5. [PMID: 29301098 DOI: 10.1016/j.neuron.2017.12.001] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Revised: 10/09/2017] [Accepted: 11/30/2017] [Indexed: 01/01/2023]
Abstract
Infections have been identified as possible risk factors for aging-related neurodegenerative diseases, but it remains unclear whether infection-related immune molecules have a causative role in neurodegeneration during aging. Here, we reveal an unexpected role of an epidermally expressed antimicrobial peptide, NLP-29 (neuropeptide-like protein 29), in triggering aging-associated dendrite degeneration in C. elegans. The age-dependent increase of nlp-29 expression is regulated by the epidermal tir-1/SARM-pmk-1/p38 MAPK innate immunity pathway. We further identify an orphan G protein-coupled receptor NPR-12 (neuropeptide receptor 12) acting in neurons as a receptor for NLP-29 and demonstrate that the autophagic machinery is involved cell autonomously downstream of NPR-12 to transduce degeneration signals. Finally, we show that fungal infections cause dendrite degeneration using a similar mechanism as in aging, through NLP-29, NPR-12, and autophagy. Our findings reveal an important causative role of antimicrobial peptides, their neuronal receptors, and the autophagy pathway in aging- and infection-associated dendrite degeneration.
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Affiliation(s)
- Lezi E
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Ting Zhou
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Sehwon Koh
- Department of Cell Biology, Duke University Medical Center, Durham, NC 27710, USA
| | - Marian Chuang
- Section of Neurobiology and Cell and Developmental Biology, Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Ruchira Sharma
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Nathalie Pujol
- Centre d'Immunologie de Marseille-Luminy, CIML, Aix Marseille Université, Inserm, CNRS, Marseille 13288, France
| | - Andrew D Chisholm
- Section of Neurobiology and Cell and Developmental Biology, Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Cagla Eroglu
- Department of Cell Biology, Duke University Medical Center, Durham, NC 27710, USA; Department of Neurobiology and Duke Institute for Brain Sciences, Duke University Medical Center, Durham, NC 27710, USA
| | - Hiroaki Matsunami
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA; Department of Neurobiology and Duke Institute for Brain Sciences, Duke University Medical Center, Durham, NC 27710, USA
| | - Dong Yan
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA; Department of Neurobiology and Duke Institute for Brain Sciences, Duke University Medical Center, Durham, NC 27710, USA.
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47
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Sundararajan L, Smith CJ, Watson JD, Millis BA, Tyska MJ, Miller DM. Actin assembly and non-muscle myosin activity drive dendrite retraction in an UNC-6/Netrin dependent self-avoidance response. PLoS Genet 2019; 15:e1008228. [PMID: 31220078 PMCID: PMC6605669 DOI: 10.1371/journal.pgen.1008228] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Revised: 07/02/2019] [Accepted: 06/04/2019] [Indexed: 01/08/2023] Open
Abstract
Dendrite growth is constrained by a self-avoidance response that induces retraction but the downstream pathways that balance these opposing mechanisms are unknown. We have proposed that the diffusible cue UNC-6(Netrin) is captured by UNC-40(DCC) for a short-range interaction with UNC-5 to trigger self-avoidance in the C. elegans PVD neuron. Here we report that the actin-polymerizing proteins UNC-34(Ena/VASP), WSP-1(WASP), UNC-73(Trio), MIG-10(Lamellipodin) and the Arp2/3 complex effect dendrite retraction in the self-avoidance response mediated by UNC-6(Netrin). The paradoxical idea that actin polymerization results in shorter rather than longer dendrites is explained by our finding that NMY-1 (non-muscle myosin II) is necessary for retraction and could therefore mediate this effect in a contractile mechanism. Our results also show that dendrite length is determined by the antagonistic effects on the actin cytoskeleton of separate sets of effectors for retraction mediated by UNC-6(Netrin) versus outgrowth promoted by the DMA-1 receptor. Thus, our findings suggest that the dendrite length depends on an intrinsic mechanism that balances distinct modes of actin assembly for growth versus retraction. Neurons may extend highly branched dendrites to detect input over a broad receptive field. The formation of actin filaments may drive dendrite elongation. The architecture of the dendritic arbor also depends on mechanisms that limit expansion. For example, sister dendrites from a single neuron usually do not overlap due to self-avoidance. Although cell surface proteins are known to mediate self-avoidance, the downstream pathways that drive dendrite retraction in this phenomenon are largely unknown. Studies of the highly branched PVD sensory neuron in C. elegans have suggested a model of self-avoidance in which the UNC-40/DCC receptor captures the diffusible cue UNC-6/Netrin at the tips of PVD dendrites where it interacts with the UNC-5 receptor on an opposing sister dendrite to induce retraction. Here we report genetic evidence that UNC-5-dependent retraction requires downstream actin polymerization. This finding evokes a paradox: How might actin polymerization drive both dendrite growth and retraction? We propose two answers: (1) Distinct sets of effectors are involved in actin assembly for growth vs retraction; (2) Non-muscle myosin interacts with a nascent actin assemblage to trigger retraction. Our results show that dendrite length depends on the balanced effects of specific molecular components that induce growth vs retraction.
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Affiliation(s)
- Lakshmi Sundararajan
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Cody J. Smith
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Joseph D. Watson
- Neuroscience Graduate Program, Vanderbilt University, Nashville, Nashville, Tennessee, United States of America
| | - Bryan A. Millis
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, Tennessee, United States of America
- Cell Imaging Shared Resource, Vanderbilt University, Nashville, Nashville, Tennessee, United States of America
- Vanderbilt Biophotonics Center, Vanderbilt University, Nashville, Nashville, Tennessee, United States of America
| | - Matthew J. Tyska
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, Tennessee, United States of America
| | - David M. Miller
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, Tennessee, United States of America
- Neuroscience Graduate Program, Vanderbilt University, Nashville, Nashville, Tennessee, United States of America
- * E-mail:
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48
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Rosa JB, Sagasti A. Developmental Neurobiology: It Takes Nrg to Separate Dendrites. Curr Biol 2019; 29:R327-R329. [PMID: 31063725 DOI: 10.1016/j.cub.2019.03.045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
The development of sensory receptive fields requires the coordinated spatial patterning of neurites from multiple sensory neuron subtypes. A new study identifies a role for neuron-skin cell interactions in preventing the bundling of dendritic arbors from distinct neurons.
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Affiliation(s)
- Jeffrey B Rosa
- Department of Molecular, Cell, and Developmental Biology, UCLA, Los Angeles, CA 90095-1606, USA
| | - Alvaro Sagasti
- Department of Molecular, Cell, and Developmental Biology, UCLA, Los Angeles, CA 90095-1606, USA.
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49
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Sundararajan L, Stern J, Miller DM. Mechanisms that regulate morphogenesis of a highly branched neuron in C. elegans. Dev Biol 2019; 451:53-67. [PMID: 31004567 DOI: 10.1016/j.ydbio.2019.04.002] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Revised: 03/09/2019] [Accepted: 04/05/2019] [Indexed: 02/08/2023]
Abstract
The shape of an individual neuron is linked to its function with axons sending signals to other cells and dendrites receiving them. Although much is known of the mechanisms for axonal outgrowth, the striking complexity of dendritic architecture has hindered efforts to uncover pathways that direct dendritic branching. Here we review the results of an experimental strategy that exploits the power of genetic analysis and live cell imaging of the PVD sensory neuron in C. elegans to reveal key molecular drivers of dendrite morphogenesis.
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Affiliation(s)
- Lakshmi Sundararajan
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN 37240, USA
| | - Jamie Stern
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN 37240, USA
| | - David M Miller
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN 37240, USA.
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50
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Inberg S, Meledin A, Kravtsov V, Iosilevskii Y, Oren-Suissa M, Podbilewicz B. Lessons from Worm Dendritic Patterning. Annu Rev Neurosci 2019; 42:365-383. [PMID: 30939099 DOI: 10.1146/annurev-neuro-072116-031437] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The structural and functional properties of neurons have intrigued scientists since the pioneering work of Santiago Ramón y Cajal. Since then, emerging cutting-edge technologies, including light and electron microscopy, electrophysiology, biochemistry, optogenetics, and molecular biology, have dramatically increased our understanding of dendritic properties. This advancement was also facilitated by the establishment of different animal model organisms, from flies to mammals. Here we describe the emerging model system of a Caenorhabditis elegans polymodal neuron named PVD, whose dendritic tree follows a stereotypical structure characterized by repeating candelabra-like structural units. In the past decade, progress has been made in understanding PVD's functions, morphogenesis, regeneration, and aging, yet many questions still remain.
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Affiliation(s)
- Sharon Inberg
- Department of Biology, Technion Israel Institute of Technology, Haifa 3200003, Israel;
| | - Anna Meledin
- Department of Biology, Technion Israel Institute of Technology, Haifa 3200003, Israel;
| | - Veronika Kravtsov
- Department of Biology, Technion Israel Institute of Technology, Haifa 3200003, Israel;
| | - Yael Iosilevskii
- Department of Biology, Technion Israel Institute of Technology, Haifa 3200003, Israel;
| | - Meital Oren-Suissa
- Department of Neurobiology, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Benjamin Podbilewicz
- Department of Biology, Technion Israel Institute of Technology, Haifa 3200003, Israel;
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