1
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Wang W, Rui M. Advances in understanding the roles of actin scaffolding and membrane trafficking in dendrite development. J Genet Genomics 2024:S1673-8527(24)00152-8. [PMID: 38925347 DOI: 10.1016/j.jgg.2024.06.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2024] [Revised: 06/18/2024] [Accepted: 06/19/2024] [Indexed: 06/28/2024]
Abstract
Dendritic morphology is typically highly branched, and the branching and synaptic abundance of dendrites can enhance the receptive range of neurons and the diversity of information received, thus providing the basis for information processing in the nervous system. Once dendritic development is aberrantly compromised or damaged, it may lead to abnormal connectivity of the neural network, affecting the function and stability of the nervous system and ultimately triggering a series of neurological disorders. Research on the regulation of dendritic developmental processes has flourished, and much progress is now being made in its regulatory mechanisms. Noteworthily, dendrites are characterized by an extremely complex dendritic arborization that cannot be attributed to individual protein functions alone, requiring a systematic analysis of the intrinsic and extrinsic signals and the coordinated roles among them. Actin cytoskeleton organization and membrane vesicle trafficking are required during dendrite development, with actin providing tracks for vesicles and vesicle trafficking in turn providing material for actin assembly. In this review, we focus on these two basic biological processes and discuss the molecular mechanisms and their synergistic effects underlying the morphogenesis of neuronal dendrites. We also offer insights and discuss strategies for the potential preventive and therapeutic treatment of neuropsychiatric disorders.
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Affiliation(s)
- Wanting Wang
- School of Life Science and Technology, The Key Laboratory of Developmental Genes and Human Disease, Southeast University, Nanjing, Jiangsu 210031, China
| | - Menglong Rui
- School of Life Science and Technology, The Key Laboratory of Developmental Genes and Human Disease, Southeast University, Nanjing, Jiangsu 210031, China.
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2
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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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3
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Shi R, Ho XY, Tao L, Taylor CA, Zhao T, Zou W, Lizzappi M, Eichel K, Shen K. Stochastic growth and selective stabilization generate stereotyped dendritic arbors. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.08.591205. [PMID: 38766073 PMCID: PMC11100716 DOI: 10.1101/2024.05.08.591205] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2024]
Abstract
Stereotyped dendritic arbors are shaped by dynamic and stochastic growth during neuronal development. It remains unclear how guidance receptors and ligands coordinate branch dynamic growth, retraction, and stabilization to specify dendritic arbors. We previously showed that extracellular ligand SAX-7/LICAM dictates the shape of the PVD sensory neuron via binding to the dendritic guidance receptor DMA-1, a single transmembrane adhesion molecule. Here, we perform structure-function analyses of DMA-1 and unexpectedly find that robust, stochastic dendritic growth does not require ligand-binding. Instead, ligand-binding inhibits growth, prevents retraction, and specifies arbor shape. Furthermore, we demonstrate that dendritic growth requires a pool of ligand-free DMA-1, which is maintained by receptor endocytosis and reinsertion to the plasma membrane via recycling endosomes. Mutants defective of DMA-1 endocytosis show severely truncated dendritic arbors. We present a model in which ligand-free guidance receptor mediates intrinsic, stochastic dendritic growth, while extracellular ligands instruct dendrite shape by inhibiting growth.
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4
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Merino‐Serrais P, Plaza‐Alonso S, Hellal F, Valero‐Freitag S, Kastanauskaite A, Plesnila N, DeFelipe J. Structural changes of CA1 pyramidal neurons after stroke in the contralesional hippocampus. Brain Pathol 2024; 34:e13222. [PMID: 38012061 PMCID: PMC11007010 DOI: 10.1111/bpa.13222] [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: 06/15/2023] [Accepted: 10/30/2023] [Indexed: 11/29/2023] Open
Abstract
Significant progress has been made with regard to understanding how the adult brain responds after a stroke. However, a large number of patients continue to suffer lifelong disabilities without adequate treatment. In the present study, we have analyzed possible microanatomical alterations in the contralesional hippocampus from the ischemic stroke mouse model tMCAo 12-14 weeks after transient middle cerebral artery occlusion. After individually injecting Lucifer yellow into pyramidal neurons from the CA1 field of the hippocampus, we performed a detailed three-dimensional analysis of the neuronal complexity, dendritic spine density, and morphology. We found that, in both apical (stratum radiatum) and basal (stratum oriens) arbors, CA1 pyramidal neurons in the contralesional hippocampus of tMCAo mice have a significantly higher neuronal complexity, as well as reduced spine density and alterations in spine volume and spine length. Our results show that when the ipsilateral hippocampus is dramatically damaged, the contralesional hippocampus exhibits several statistically significant selective alterations. However, these alterations are not as significant as expected, which may help to explain the recovery of hippocampal function after stroke. Further anatomical and physiological studies are necessary to better understand the modifications in the "intact" contralesional lesioned brain regions, which are probably fundamental to recover functions after stroke.
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Affiliation(s)
- Paula Merino‐Serrais
- Laboratorio Cajal de Circuitos Corticales, Centro de Tecnología BiomédicaUniversidad Politécnica de MadridMadridSpain
- Departamento de Neurobiología Funcional y de SistemasInstituto Cajal, CSICMadridSpain
| | - Sergio Plaza‐Alonso
- Laboratorio Cajal de Circuitos Corticales, Centro de Tecnología BiomédicaUniversidad Politécnica de MadridMadridSpain
- Departamento de Neurobiología Funcional y de SistemasInstituto Cajal, CSICMadridSpain
| | - Farida Hellal
- Laboratory of Experimental Stroke Research, Institute for Stroke and Dementia Research (ISD), University Hospital, Ludwig‐Maximilians‐University Munich (LMU)MunichGermany
- iTERM, Helmholtz CenterMunichGermany
- Munich Cluster of Systems Neurology (Synergy)MunichGermany
| | - Susana Valero‐Freitag
- Laboratory of Experimental Stroke Research, Institute for Stroke and Dementia Research (ISD), University Hospital, Ludwig‐Maximilians‐University Munich (LMU)MunichGermany
| | - Asta Kastanauskaite
- Laboratorio Cajal de Circuitos Corticales, Centro de Tecnología BiomédicaUniversidad Politécnica de MadridMadridSpain
- Departamento de Neurobiología Funcional y de SistemasInstituto Cajal, CSICMadridSpain
| | - Nikolaus Plesnila
- Laboratory of Experimental Stroke Research, Institute for Stroke and Dementia Research (ISD), University Hospital, Ludwig‐Maximilians‐University Munich (LMU)MunichGermany
- Munich Cluster of Systems Neurology (Synergy)MunichGermany
| | - Javier DeFelipe
- Laboratorio Cajal de Circuitos Corticales, Centro de Tecnología BiomédicaUniversidad Politécnica de MadridMadridSpain
- Departamento de Neurobiología Funcional y de SistemasInstituto Cajal, CSICMadridSpain
- CIBER de Enfermedades Neurodegenerativas, Instituto de Salud Carlos IIIMadridSpain
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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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Zhu Y, Tesone Z, Tan M, Hardin J. TIAM-1 regulates polarized protrusions during dorsal intercalation in the Caenorhabditis elegans embryo through both its GEF and N-terminal domains. J Cell Sci 2024; 137:jcs261509. [PMID: 38345070 PMCID: PMC10949065 DOI: 10.1242/jcs.261509] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Accepted: 02/05/2024] [Indexed: 02/27/2024] Open
Abstract
Mediolateral cell intercalation is a morphogenetic strategy used throughout animal development to reshape tissues. Dorsal intercalation in the Caenorhabditis elegans embryo involves the mediolateral intercalation of two rows of dorsal epidermal cells to create a single row that straddles the dorsal midline, and thus is a simple model to study cell intercalation. Polarized protrusive activity during dorsal intercalation requires the C. elegans Rac and RhoG orthologs CED-10 and MIG-2, but how these GTPases are regulated during intercalation has not been thoroughly investigated. In this study, we characterized the role of the Rac-specific guanine nucleotide exchange factor (GEF) TIAM-1 in regulating actin-based protrusive dynamics during dorsal intercalation. We found that TIAM-1 can promote formation of the main medial lamellipodial protrusion extended by intercalating cells through its canonical GEF function, whereas its N-terminal domains function to negatively regulate the generation of ectopic filiform protrusions around the periphery of intercalating cells. We also show that the guidance receptor UNC-5 inhibits these ectopic filiform protrusions in dorsal epidermal cells and that this effect is in part mediated via TIAM-1. These results expand the network of proteins that regulate basolateral protrusive activity during directed rearrangement of epithelial cells in animal embryos.
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Affiliation(s)
- Yuyun Zhu
- Genetics PhD Program, University of Wisconsin, Madison, WI 53706, USA
| | - Zoe Tesone
- Cellular and Molecular Biology PhD Program, University of Wisconsin, Madison, WI 53706, USA
| | - Minyi Tan
- Department of Integrative Biology, University of Wisconsin, Madison, WI 53706, USA
| | - Jeff Hardin
- Genetics PhD Program, University of Wisconsin, Madison, WI 53706, USA
- Cellular and Molecular Biology PhD Program, University of Wisconsin, Madison, WI 53706, USA
- Department of Integrative Biology, University of Wisconsin, Madison, WI 53706, USA
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7
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Ouzounidis VR, Prevo B, Cheerambathur DK. Sculpting the dendritic landscape: Actin, microtubules, and the art of arborization. Curr Opin Cell Biol 2023; 84:102214. [PMID: 37544207 DOI: 10.1016/j.ceb.2023.102214] [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: 07/06/2022] [Revised: 06/20/2023] [Accepted: 07/05/2023] [Indexed: 08/08/2023]
Abstract
Dendrites are intricately designed neuronal compartments that play a vital role in the gathering and processing of sensory or synaptic inputs. Their diverse and elaborate structures are distinct features of neuronal organization and function. Central to the generation of these dendritic arbors is the neuronal cytoskeleton. In this review, we delve into the current progress toward our understanding of how dendrite arbors are generated and maintained, focusing on the role of the actin and microtubule cytoskeleton.
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Affiliation(s)
- Vasileios R Ouzounidis
- Wellcome Centre for Cell Biology & Institute of Cell Biology, School of Biological Sciences, The University of Edinburgh, Edinburgh, EH9 3BF, UK
| | - Bram Prevo
- Wellcome Centre for Cell Biology & Institute of Cell Biology, School of Biological Sciences, The University of Edinburgh, Edinburgh, EH9 3BF, UK
| | - Dhanya K Cheerambathur
- Wellcome Centre for Cell Biology & Institute of Cell Biology, School of Biological Sciences, The University of Edinburgh, Edinburgh, EH9 3BF, UK.
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8
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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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9
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Kramer DA, Narvaez-Ortiz HY, Patel U, Shi R, Shen K, Nolen BJ, Roche J, Chen B. The intrinsically disordered cytoplasmic tail of a dendrite branching receptor uses two distinct mechanisms to regulate the actin cytoskeleton. eLife 2023; 12:e88492. [PMID: 37555826 PMCID: PMC10411975 DOI: 10.7554/elife.88492] [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: 04/10/2023] [Accepted: 05/01/2023] [Indexed: 08/10/2023] Open
Abstract
Dendrite morphogenesis is essential for neural circuit formation, yet the molecular mechanisms underlying complex dendrite branching remain elusive. Previous studies on the highly branched Caenorhabditis elegans PVD sensory neuron identified a membrane co-receptor complex that links extracellular signals to intracellular actin remodeling machinery, promoting high-order dendrite branching. In this complex, the claudin-like transmembrane protein HPO-30 recruits the WAVE regulatory complex (WRC) to dendrite branching sites, stimulating the Arp2/3 complex to polymerize actin. We report here our biochemical and structural analysis of this interaction, revealing that the intracellular domain (ICD) of HPO-30 is intrinsically disordered and employs two distinct mechanisms to regulate the actin cytoskeleton. First, HPO-30 ICD binding to the WRC requires dimerization and involves the entire ICD sequence, rather than a short linear peptide motif. This interaction enhances WRC activation by the GTPase Rac1. Second, HPO-30 ICD directly binds to the sides and barbed end of actin filaments. Binding to the barbed end requires ICD dimerization and inhibits both actin polymerization and depolymerization, resembling the actin capping protein CapZ. These dual functions provide an intriguing model of how membrane proteins can integrate distinct mechanisms to fine-tune local actin dynamics.
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Affiliation(s)
- Daniel A Kramer
- Roy J Carver Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State UniversityAmesUnited States
| | - Heidy Y Narvaez-Ortiz
- Department of Chemistry and Biochemistry, Institute of Molecular Biology, University of OregonEugeneUnited States
| | - Urval Patel
- Roy J Carver Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State UniversityAmesUnited States
| | - Rebecca Shi
- Department of Biology, Stanford UniversityStanfordUnited States
- Neurosciences IDP, Stanford UniversityStanfordUnited States
| | - Kang Shen
- Department of Biology, Stanford UniversityStanfordUnited States
- Howard Hughes Medical Institute, Stanford UniversityStanfordUnited States
| | - Brad J Nolen
- Department of Chemistry and Biochemistry, Institute of Molecular Biology, University of OregonEugeneUnited States
| | - Julien Roche
- Roy J Carver Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State UniversityAmesUnited States
| | - Baoyu Chen
- Roy J Carver Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State UniversityAmesUnited States
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10
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Zhu Y, Hardin J. TIAM-1 regulates polarized protrusions during dorsal intercalation in the C. elegans embryo through both its GEF and N-terminal domains. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.24.550374. [PMID: 37546890 PMCID: PMC10402040 DOI: 10.1101/2023.07.24.550374] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/08/2023]
Abstract
Mediolateral cell intercalation is a morphogenetic strategy used throughout animal development to reshape tissues. Dorsal intercalation in the C. elegans embryo involves the mediolateral intercalation of two rows of dorsal epidermal cells to create a single row that straddles the dorsal midline, and so is a simple model to study cell intercalation. Polarized protrusive activity during dorsal intercalation requires the C. elegans Rac and RhoG orthologs CED-10 and MIG-2, but how these GTPases are regulated during intercalation has not been thoroughly investigated. In this study, we characterize the role of the Rac-specific guanine nucleotide exchange factor (GEF), TIAM-1, in regulating actin-based protrusive dynamics during dorsal intercalation. We find that TIAM-1 can promote protrusion formation through its canonical GEF function, while its N-terminal domains function to negatively regulate this activity, preventing the generation of ectopic protrusions in intercalating cells. We also show that the guidance receptor UNC-5 inhibits ectopic protrusive activity in dorsal epidermal cells, and that this effect is in part mediated via TIAM-1. These results expand the network of proteins that regulate basolateral protrusive activity during directed cell rearrangement. Summary statement TIAM-1 activates the Rac pathway to promote protrusion formation via its GEF domain, while its N-terminal domains suppress ectopic protrusions during dorsal intercalation in the C. elegans embryo.
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11
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Kokan N, Witt S, Sandhu S, Hutter H. lron-11 guides axons in the ventral nerve cord of Caenorhabditis elegans. PLoS One 2022; 17:e0278258. [PMID: 36449480 PMCID: PMC9710760 DOI: 10.1371/journal.pone.0278258] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Accepted: 11/13/2022] [Indexed: 12/02/2022] Open
Abstract
For the nervous system to develop properly, neurons must connect in a precise way to form functional networks. This requires that outgrowing neuronal processes (axons) navigate to their target areas, where they establish proper synaptic connections. The molecular basis of this navigation process is not firmly understood. A candidate family containing putative receptors acting in various aspects of neuronal development including axon navigation are transmembrane proteins of the extracellular Leucine-Rich Repeat family (eLRRs). We systematically tested members of this family in C. elegans for a role in axon navigation in the ventral nerve cord (VNC). We found that lron-11 mutants showed VNC navigation defects in several classes of neurons, including a pioneer neuron and various classes of interneurons and motoneurons. This suggests that while most members of the lron-family do not seem to have a role in axon navigation in the VNC, lron-11 is likely to be a receptor required for correct navigation of axons in the VNC of C. elegans.
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Affiliation(s)
- Nikolas Kokan
- Department of Biological Sciences, Simon Fraser University, Burnaby, BC, Canada
| | - Skyla Witt
- Department of Biological Sciences, Simon Fraser University, Burnaby, BC, Canada
| | - Saru Sandhu
- Department of Biological Sciences, Simon Fraser University, Burnaby, BC, Canada
| | - Harald Hutter
- Department of Biological Sciences, Simon Fraser University, Burnaby, BC, Canada
- * E-mail:
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12
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Suzuki N, Zou Y, Sun H, Eichel K, Shao M, Shih M, Shen K, Chang C. Two intrinsic timing mechanisms set start and end times for dendritic arborization of a nociceptive neuron. Proc Natl Acad Sci U S A 2022; 119:e2210053119. [PMID: 36322763 PMCID: PMC9659368 DOI: 10.1073/pnas.2210053119] [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: 06/15/2022] [Accepted: 10/04/2022] [Indexed: 11/05/2022] Open
Abstract
Choreographic dendritic arborization takes place within a defined time frame, but the timing mechanism is currently not known. Here, we report that the precisely timed lin-4-lin-14 regulatory circuit triggers an initial dendritic growth activity, whereas the precisely timed lin-28-let-7-lin-41 regulatory circuit signals a subsequent developmental decline in dendritic growth ability, hence restricting dendritic arborization within a set time frame. Loss-of-function mutations in the lin-4 microRNA gene cause limited dendritic outgrowth, whereas loss-of-function mutations in its direct target, the lin-14 transcription factor gene, cause precocious and excessive outgrowth. In contrast, loss-of-function mutations in the let-7 microRNA gene prevent a developmental decline in dendritic growth ability, whereas loss-of-function mutations in its direct target, the lin-41 tripartite motif protein gene, cause further decline. lin-4 and let-7 regulatory circuits are expressed in the right place at the right time to set start and end times for dendritic arborization. Replacing the lin-4 upstream cis-regulatory sequence at the lin-4 locus with a late-onset let-7 upstream cis-regulatory sequence delays dendrite arborization, whereas replacing the let-7 upstream cis-regulatory sequence at the let-7 locus with an early-onset lin-4 upstream cis-regulatory sequence causes a precocious decline in dendritic growth ability. Our results indicate that the lin-4-lin-14 and the lin-28-let-7-lin-41 regulatory circuits control the timing of dendrite arborization through antagonistic regulation of the DMA-1 receptor level on dendrites. The LIN-14 transcription factor likely directly represses dma-1 gene expression through a transcriptional means, whereas the LIN-41 tripartite motif protein likely indirectly promotes dma-1 gene expression through a posttranscriptional means.
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Affiliation(s)
- Nobuko Suzuki
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, IL 60607
| | - Yan Zou
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, IL 60607
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - HaoSheng Sun
- Department of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL 35233
| | - Kelsie Eichel
- HHMI, Stanford University, Stanford, CA 94305
- Department of Biology, Stanford University, Stanford, CA 94305
| | - Meiyu Shao
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Mushaine Shih
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, IL 60607
| | - Kang Shen
- HHMI, Stanford University, Stanford, CA 94305
- Department of Biology, Stanford University, Stanford, CA 94305
| | - Chieh Chang
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, IL 60607
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13
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Lin CH, Chen YC, Chan SP, Ou CY. TIAM-1 differentially regulates dendritic and axonal microtubule organization in patterning neuronal development through its multiple domains. PLoS Genet 2022; 18:e1010454. [PMID: 36223408 PMCID: PMC9612824 DOI: 10.1371/journal.pgen.1010454] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Revised: 10/27/2022] [Accepted: 09/29/2022] [Indexed: 12/02/2022] Open
Abstract
Axon and dendrite development require the cooperation of actin and microtubule cytoskeletons. Microtubules form a well-organized network to direct polarized trafficking and support neuronal processes formation with distinct actin structures. However, it is largely unknown how cytoskeleton regulators differentially regulate microtubule organization in axon and dendrite development. Here, we characterize the role of actin regulators in axon and dendrite development and show that the RacGEF TIAM-1 regulates dendritic patterns through its N-terminal domains and suppresses axon growth through its C-terminal domains. TIAM-1 maintains plus-end-out microtubule orientation in posterior dendrites and prevents the accumulation of microtubules in the axon. In somatodendritic regions, TIAM-1 interacts with UNC-119 and stabilizes the organization between actin filaments and microtubules. UNC-119 is required for TIAM-1 to control axon growth, and its expression levels determine axon length. Taken together, TIAM-1 regulates neuronal microtubule organization and patterns axon and dendrite development respectively through its different domains.
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Affiliation(s)
- Chih-Hsien Lin
- Institute of Biochemistry and Molecular Biology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Ying-Chun Chen
- Institute of Biochemistry and Molecular Biology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Shih-Peng Chan
- Graduate Institute of Microbiology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Chan-Yen Ou
- Institute of Biochemistry and Molecular Biology, College of Medicine, National Taiwan University, Taipei, Taiwan
- * E-mail:
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14
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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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15
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Merino-Serrais P, Plaza-Alonso S, Hellal F, Valero-Freitag S, Kastanauskaite A, Muñoz A, Plesnila N, DeFelipe J. Microanatomical study of pyramidal neurons in the contralesional somatosensory cortex after experimental ischemic stroke. Cereb Cortex 2022; 33:1074-1089. [PMID: 35353195 PMCID: PMC9930620 DOI: 10.1093/cercor/bhac121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Revised: 03/01/2022] [Accepted: 03/02/2022] [Indexed: 11/13/2022] Open
Abstract
At present, many studies support the notion that after stroke, remote regions connected to the infarcted area are also affected and may contribute to functional outcome. In the present study, we have analyzed possible microanatomical alterations in pyramidal neurons from the contralesional hemisphere after induced stroke. We performed intracellular injections of Lucifer yellow in pyramidal neurons from layer III in the somatosensory cortex of the contralesional hemisphere in an ischemic stroke mouse model. A detailed 3-dimensional analysis of the neuronal complexity and morphological alterations of dendritic spines was then performed. Our results demonstrate that pyramidal neurons from layer III in the somatosensory cortex of the contralesional hemisphere show selective changes in their dendritic arbors, namely, less dendritic complexity of the apical dendritic arbor-but no changes in the basal dendritic arbor. In addition, we found differences in spine morphology in both apical and basal dendrites comparing the contralesional hemisphere with the lesional hemisphere. Our results show that pyramidal neurons of remote areas connected to the infarct zone exhibit a series of selective changes in neuronal complexity and morphological distribution of dendritic spines, supporting the hypothesis that remote regions connected to the peri-infarcted area are also affected after stroke.
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Affiliation(s)
- Paula Merino-Serrais
- Corresponding author: Laboratorio Cajal de Circuitos Corticales, Centro de Tecnología Biomédica, Universidad Politécnica de Madrid, Campus Montegancedo S/N, Pozuelo de Alarcón, Madrid 28223/Instituto Cajal (CSIC), Avenida Doctor Arce, 37, Madrid 28002, Spain.
| | - Sergio Plaza-Alonso
- Laboratorio Cajal de Circuitos Corticales, Centro de Tecnología Biomédica, Universidad Politécnica de Madrid, Madrid 28223, Spain,Departamento de Neurobiología Funcional y de Sistemas, Instituto Cajal, CSIC, Madrid 28002, Spain
| | - Farida Hellal
- Institute for Stroke and Dementia Research (ISD), University of Munich, Munich 81337, Germany,iTERM, Helmholtz center, Munich 85764, Germany
| | - Susana Valero-Freitag
- Institute for Stroke and Dementia Research (ISD), University of Munich, Munich 81337, Germany
| | - Asta Kastanauskaite
- Laboratorio Cajal de Circuitos Corticales, Centro de Tecnología Biomédica, Universidad Politécnica de Madrid, Madrid 28223, Spain,Departamento de Neurobiología Funcional y de Sistemas, Instituto Cajal, CSIC, Madrid 28002, Spain
| | - Alberto Muñoz
- Laboratorio Cajal de Circuitos Corticales, Centro de Tecnología Biomédica, Universidad Politécnica de Madrid, Madrid 28223, Spain,Departamento de Neurobiología Funcional y de Sistemas, Instituto Cajal, CSIC, Madrid 28002, Spain,Departamento de Biología Celular, Universidad Complutense, Madrid 28040, Spain
| | - Nikolaus Plesnila
- Institute for Stroke and Dementia Research (ISD), University of Munich, Munich 81337, Germany,Munich Cluster of Systems Neurology (Synergy), Munich 85764, Germany
| | - Javier DeFelipe
- Laboratorio Cajal de Circuitos Corticales, Centro de Tecnología Biomédica, Universidad Politécnica de Madrid, Madrid 28223, Spain,Departamento de Neurobiología Funcional y de Sistemas, Instituto Cajal, CSIC, Madrid 28002, Spain,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas. (CIBERNED), ISCIII, Madrid 28031, Spain
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16
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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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17
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Shi R, Kramer DA, Chen B, Shen K. A two-step actin polymerization mechanism drives dendrite branching. Neural Dev 2021; 16:3. [PMID: 34281597 PMCID: PMC8290545 DOI: 10.1186/s13064-021-00154-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2021] [Accepted: 06/14/2021] [Indexed: 11/10/2022] Open
Abstract
Background Dendrite morphogenesis plays an essential role in establishing the connectivity and receptive fields of neurons during the development of the nervous system. To generate the diverse morphologies of branched dendrites, neurons use external cues and cell surface receptors to coordinate intracellular cytoskeletal organization; however, the molecular mechanisms of how this signaling forms branched dendrites are not fully understood. Methods We performed in vivo time-lapse imaging of the PVD neuron in C. elegans in several mutants of actin regulatory proteins, such as the WAVE Regulatory Complex (WRC) and UNC-34 (homolog of Enabled/Vasodilator-stimulated phosphoprotein (Ena/VASP)). We examined the direct interaction between the WRC and UNC-34 and analyzed the localization of UNC-34 in vivo using transgenic worms expressing UNC-34 fused to GFP. Results We identify a stereotyped sequence of morphological events during dendrite outgrowth in the PVD neuron in C. elegans. Specifically, local increases in width (“swellings”) give rise to filopodia to facilitate a “rapid growth and pause” mode of growth. In unc-34 mutants, filopodia fail to form but swellings are intact. In WRC mutants, dendrite growth is largely absent, resulting from a lack of both swelling and filopodia formation. We also found that UNC-34 can directly bind to the WRC. Disrupting this binding by deleting the UNC-34 EVH1 domain prevented UNC-34 from localizing to swellings and dendrite tips, resulting in a stunted dendritic arbor and reduced filopodia outgrowth. Conclusions We propose that regulators of branched and linear F-actin cooperate to establish dendritic branches. By combining our work with existing literature, we propose that the dendrite guidance receptor DMA-1 recruits the WRC, which polymerizes branched F-actin to generate “swellings” on a mother dendrite. Then, WRC recruits the actin elongation factor UNC-34/Ena/VASP to initiate growth of a new dendritic branch from the swelling, with the help of the actin-binding protein UNC-115/abLIM. Extension of existing dendrites also proceeds via swelling formation at the dendrite tip followed by UNC-34-mediated outgrowth. Following dendrite initiation and extension, the stabilization of branches by guidance receptors further recruits WRC, resulting in an iterative process to build a complex dendritic arbor. Supplementary Information The online version contains supplementary material available at 10.1186/s13064-021-00154-0.
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Affiliation(s)
- Rebecca Shi
- Department of Biology, Stanford University, Stanford, CA, 94305, USA.,Neurosciences IDP, Stanford University, Stanford, CA, 94305, USA
| | - Daniel A Kramer
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, IA, 50011, USA
| | - Baoyu Chen
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, IA, 50011, USA
| | - Kang Shen
- Department of Biology, Stanford University, Stanford, CA, 94305, USA. .,Howard Hughes Medical Institute, Stanford University, Stanford, CA, 94305, USA.
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18
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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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19
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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] [Track Full Text] [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.
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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
| | | | - Tom Shemesh
- Faculty of Biology, Technion–Israel Institute of Technology, Haifa, Israel
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20
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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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21
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Feng Z, Zhao Y, Li T, Nie W, Yang X, Wang X, Wu J, Liao J, Zou Y. CATP-8/P5A ATPase Regulates ER Processing of the DMA-1 Receptor for Dendritic Branching. Cell Rep 2021; 32:108101. [PMID: 32905774 DOI: 10.1016/j.celrep.2020.108101] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Revised: 06/05/2020] [Accepted: 08/11/2020] [Indexed: 10/23/2022] Open
Abstract
Dendrite morphogenesis is essential for a neuron to establish its receptive field and is, thus, the anatomical basis for the proper functioning of the nervous system. The molecular mechanisms governing dendrite branching are not fully understood. Using the multi-dendritic PVD neuron in the nematode Caenorhabditis elegans, we identify CATP-8/P5A ATPase as a key regulator of dendrite branching that controls the translocation of the DMA-1 receptor to the endoplasmic reticulum (ER). The specific signal peptide of DMA-1 and the ATPase activity of CATP-8 are essential for this process. Our results reveal that P5A ATPase may regulate protein translocation in the ER.
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Affiliation(s)
- Zhigang Feng
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China; Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yupeng Zhao
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Tingting Li
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China; Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Wang Nie
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China; Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Xiaoyan Yang
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China; Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Xinjian Wang
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Jianguo Wu
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Jun Liao
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Yan Zou
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China; Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China.
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22
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Chen YC, Huang HR, Hsu CH, Ou CY. CRMP/UNC-33 organizes microtubule bundles for KIF5-mediated mitochondrial distribution to axon. PLoS Genet 2021; 17:e1009360. [PMID: 33571181 PMCID: PMC7904166 DOI: 10.1371/journal.pgen.1009360] [Citation(s) in RCA: 9] [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: 07/03/2020] [Revised: 02/24/2021] [Accepted: 11/11/2020] [Indexed: 12/13/2022] Open
Abstract
Neurons are highly specialized cells with polarized cellular processes and subcellular domains. As vital organelles for neuronal functions, mitochondria are distributed by microtubule-based transport systems. Although the essential components of mitochondrial transport including motors and cargo adaptors are identified, it is less clear how mitochondrial distribution among somato-dendritic and axonal compartment is regulated. Here, we systematically study mitochondrial motors, including four kinesins, KIF5, KIF17, KIF1, KLP-6, and dynein, and transport regulators in C. elegans PVD neurons. Among all these motors, we found that mitochondrial export from soma to neurites is mainly mediated by KIF5/UNC-116. Interestingly, UNC-116 is especially important for axonal mitochondria, while dynein removes mitochondria from all plus-end dendrites and the axon. We surprisingly found one mitochondrial transport regulator for minus-end dendritic compartment, TRAK-1, and two mitochondrial transport regulators for axonal compartment, CRMP/UNC-33 and JIP3/UNC-16. While JIP3/UNC-16 suppresses axonal mitochondria, CRMP/UNC-33 is critical for axonal mitochondria; nearly no axonal mitochondria present in unc-33 mutants. We showed that UNC-33 is essential for organizing the population of UNC-116-associated microtubule bundles, which are tracks for mitochondrial trafficking. Disarrangement of these tracks impedes mitochondrial transport to the axon. In summary, we identified a compartment-specific transport regulation of mitochondria by UNC-33 through organizing microtubule tracks for different kinesin motors other than microtubule polarity.
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Affiliation(s)
- Ying-Chun Chen
- Institute of Biochemistry and Molecular Biology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Hao-Ru Huang
- Institute of Biochemistry and Molecular Biology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Chia-Hao Hsu
- Institute of Biochemistry and Molecular Biology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Chan-Yen Ou
- Institute of Biochemistry and Molecular Biology, College of Medicine, National Taiwan University, Taipei, Taiwan
- * E-mail:
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23
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Cheng J, Scala F, Blanco FA, Niu S, Firozi K, Keehan L, Mulherkar S, Froudarakis E, Li L, Duman JG, Jiang X, Tolias KF. The Rac-GEF Tiam1 Promotes Dendrite and Synapse Stabilization of Dentate Granule Cells and Restricts Hippocampal-Dependent Memory Functions. J Neurosci 2021; 41:1191-1206. [PMID: 33328293 PMCID: PMC7888217 DOI: 10.1523/jneurosci.3271-17.2020] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Revised: 11/25/2020] [Accepted: 12/01/2020] [Indexed: 12/14/2022] Open
Abstract
The dentate gyrus (DG) controls information flow into the hippocampus and is critical for learning, memory, pattern separation, and spatial coding, while DG dysfunction is associated with neuropsychiatric disorders. Despite its importance, the molecular mechanisms regulating DG neural circuit assembly and function remain unclear. Here, we identify the Rac-GEF Tiam1 as an important regulator of DG development and associated memory processes. In the hippocampus, Tiam1 is predominantly expressed in the DG throughout life. Global deletion of Tiam1 in male mice results in DG granule cells with simplified dendritic arbors, reduced dendritic spine density, and diminished excitatory synaptic transmission. Notably, DG granule cell dendrites and synapses develop normally in Tiam1 KO mice, resembling WT mice at postnatal day 21 (P21), but fail to stabilize, leading to dendrite and synapse loss by P42. These results indicate that Tiam1 promotes DG granule cell dendrite and synapse stabilization late in development. Tiam1 loss also increases the survival, but not the production, of adult-born DG granule cells, possibly because of greater circuit integration as a result of decreased competition with mature granule cells for synaptic inputs. Strikingly, both male and female mice lacking Tiam1 exhibit enhanced contextual fear memory and context discrimination. Together, these results suggest that Tiam1 is a key regulator of DG granule cell stabilization and function within hippocampal circuits. Moreover, based on the enhanced memory phenotype of Tiam1 KO mice, Tiam1 may be a potential target for the treatment of disorders involving memory impairments.SIGNIFICANCE STATEMENT The dentate gyrus (DG) is important for learning, memory, pattern separation, and spatial navigation, and its dysfunction is associated with neuropsychiatric disorders. However, the molecular mechanisms controlling DG formation and function remain elusive. By characterizing mice lacking the Rac-GEF Tiam1, we demonstrate that Tiam1 promotes the stabilization of DG granule cell dendritic arbors, spines, and synapses, whereas it restricts the survival of adult-born DG granule cells, which compete with mature granule cells for synaptic integration. Notably, mice lacking Tiam1 also exhibit enhanced contextual fear memory and context discrimination. These findings establish Tiam1 as an essential regulator of DG granule cell development, and identify it as a possible therapeutic target for memory enhancement.
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Affiliation(s)
- Jinxuan Cheng
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas 77030
- Department of Neuroscience, Baylor College of Medicine, Houston, Texas 77030
| | - Federico Scala
- Department of Neuroscience, Baylor College of Medicine, Houston, Texas 77030
| | - Francisco A Blanco
- Department of Neuroscience, Baylor College of Medicine, Houston, Texas 77030
- Integrative Molecular and Biomedical Science Graduate Program, Baylor College of Medicine, Houston, Texas 77030
| | - Sanyong Niu
- Department of Neuroscience, Baylor College of Medicine, Houston, Texas 77030
| | - Karen Firozi
- Department of Neuroscience, Baylor College of Medicine, Houston, Texas 77030
| | - Laura Keehan
- Department of Biosciences, Rice University, Houston, Texas 77005
| | - Shalaka Mulherkar
- Department of Neuroscience, Baylor College of Medicine, Houston, Texas 77030
| | | | - Lingyong Li
- Department of Neuroscience, Baylor College of Medicine, Houston, Texas 77030
| | - Joseph G Duman
- Department of Neuroscience, Baylor College of Medicine, Houston, Texas 77030
| | - Xiaolong Jiang
- Department of Neuroscience, Baylor College of Medicine, Houston, Texas 77030
- Jan and Dan Duncan Neurological Research Institute at Texas Children's Hospital, Houston, Texas 77030
| | - Kimberley F Tolias
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas 77030
- Department of Neuroscience, Baylor College of Medicine, Houston, Texas 77030
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24
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Jin H, Kim B. Neurite Branching Regulated by Neuronal Cell Surface Molecules in Caenorhabditis elegans. Front Neuroanat 2020; 14:59. [PMID: 32973467 PMCID: PMC7471659 DOI: 10.3389/fnana.2020.00059] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Accepted: 08/04/2020] [Indexed: 01/02/2023] Open
Abstract
The high synaptic density in the nervous system results from the ability of neurites to branch. Neuronal cell surface molecules play central roles during neurite branch formation. The underlying mechanisms of surface molecule activity have often been elucidated using invertebrates with simple nervous systems. Here, we review recent advances in understanding the molecular mechanisms of neurite branching in the nematode Caenorhabditis elegans. We discuss how cell surface receptor complexes link to and modulate actin dynamics to regulate dendritic and axonal branch formation. The mechanisms of neurite branching are often coupled with other neural circuit developmental processes, such as synapse formation and axon guidance, via the same cell-cell surface molecular interactions. We also cover ectopic and sex-specific neurite branching in C. elegans in an attempt to illustrate the importance of these studies in contributing to our understanding of conserved cell surface molecule regulation of neurite branch formation.
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Affiliation(s)
- HoYong Jin
- Department of Life Science, Dongguk University-Seoul, Goyang, South Korea
| | - Byunghyuk Kim
- Department of Life Science, Dongguk University-Seoul, Goyang, South Korea
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25
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Tikiyani V, Babu K. Claudins in the brain: Unconventional functions in neurons. Traffic 2020; 20:807-814. [PMID: 31418988 DOI: 10.1111/tra.12685] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2019] [Revised: 08/09/2019] [Accepted: 08/13/2019] [Indexed: 12/13/2022]
Abstract
Bonafide claudin proteins are functional and structural components of tight junctions and are largely responsible for barrier formation across epithelial and endothelial membranes. However, current advances in the understanding of claudin biology have revealed their unexpected functions in the brain. Apart from maintaining blood-brain barriers in the brain, other functions of claudins in neurons and at synapses have been largely elusive and are just coming to light. In this review, we summarize the functions of claudins in the brain and their association in neuronal diseases. Further, we go on to cover some recent studies that show that claudins play signaling functions in neurons by regulating trafficking of postsynaptic receptors and controlling dendritic morphogenesis in the model organism Caenorhabditis elegans.
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Affiliation(s)
- Vina Tikiyani
- Department of Biological Sciences, Indian Institute of Science Education and Research (IISER), Mohali, Punjab, India
| | - Kavita Babu
- Department of Biological Sciences, Indian Institute of Science Education and Research (IISER), Mohali, Punjab, India.,Centre for Neuroscience (CNS), Indian Institute of Science (IISc), Bangalore, India
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26
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ZHAO W, ZOU W. [Intrinsic and extrinsic mechanisms regulating neuronal dendrite morphogenesis]. Zhejiang Da Xue Xue Bao Yi Xue Ban 2020; 49:90-99. [PMID: 32621417 PMCID: PMC8800678 DOI: 10.3785/j.issn.1008-9292.2020.02.09] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Accepted: 08/15/2019] [Indexed: 06/11/2023]
Abstract
Neurons are the structural and functional unit of the nervous system. Precisely regulated dendrite morphogenesis is the basis of neural circuit assembly. Numerous studies have been conducted to explore the regulatory mechanisms of dendritic morphogenesis. According to their action regions, we divide them into two categories: the intrinsic and extrinsic regulators of neuronal dendritic morphogenesis. Intrinsic factors are cell type-specific transcription factors, actin polymerization or depolymerization regulators and regulators of the secretion or endocytic pathways. These intrinsic factors are produced by neuron itself and play an important role in regulating the development of dendrites. The extrinsic regulators are either secreted proteins or transmembrane domain containing cell adhesion molecules. They often form receptor-ligand pairs to mediate attractive or repulsive dendritic guidance. In this review, we summarize recent findings on the intrinsic and external molecular mechanisms of dendrite morphogenesis from multiple model organisms, including Caenorhabditis elegans, Drosophila and mice. These studies will provide a better understanding on how defective dendrite development and maintenance are associated with neurological diseases.
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27
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Hu J, Li C, Hua Y, Liu P, Gao B, Wang Y, Bai Y. Constraint-induced movement therapy improves functional recovery after ischemic stroke and its impacts on synaptic plasticity in sensorimotor cortex and hippocampus. Brain Res Bull 2020; 160:8-23. [PMID: 32298779 DOI: 10.1016/j.brainresbull.2020.04.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Revised: 03/12/2020] [Accepted: 04/06/2020] [Indexed: 01/28/2023]
Abstract
Constraint-induced movement therapy (CIMT) has proven to be an effective way to restore functional deficits following stroke in human and animal studies, but its underlying neural plasticity mechanism remains unknown. Accumulating evidence indicates that rehabilitation after stroke is closely associated with synaptic plasticity. We therefore investigated the impact of CIMT on synaptic plasticity in ipsilateral and contralateral brain of rats following stroke. Rats were subjected to 90 minutes of transient middle cerebral artery occlusion (MCAO). CIMT was performed from 7 days after stroke and lasted for two weeks. Modified Neurology Severity Score (mNSS) and the ladder rung walking task tests were conducted at 7,14 and 21 days after stroke. Golgi-Cox staining was used to observe the plasticity changes of dendrites and dendritic spines. The expression of glutamate receptors (GluR1, GluR2 and NR1) were examined by western blot. Our data suggest that the dendrites and dendritic spines are damaged to varying degrees in bilateral sensorimotor cortex and hippocampus after acute stroke. CIMT treatment enhances the plasticity of dendrites and dendritic spines in the ipsilateral and contralateral sensorimotor cortex, increases the expression of synaptic GluR2 in ipsilateral sensorimotor cortex, which may be mechanisms for CIMT to improve functional recovery after ischemic stroke.
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Affiliation(s)
- Jian Hu
- Department of Rehabilitation Medicine, Huashan Hospital, Fudan University, Shanghai, China
| | - Ce Li
- Department of Rehabilitation Medicine, Huashan Hospital, Fudan University, Shanghai, China
| | - Yan Hua
- Department of Rehabilitation Medicine, Huashan Hospital, Fudan University, Shanghai, China
| | - Peile Liu
- Department of Rehabilitation Medicine, Huashan Hospital, Fudan University, Shanghai, China
| | - Beiyao Gao
- Department of Rehabilitation Medicine, Huashan Hospital, Fudan University, Shanghai, China
| | - Yuyuan Wang
- Department of Rehabilitation Medicine, Huashan Hospital, Fudan University, Shanghai, China
| | - Yulong Bai
- Department of Rehabilitation Medicine, Huashan Hospital, Fudan University, Shanghai, China.
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28
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Tiam1 is Critical for Glutamatergic Synapse Structure and Function in the Hippocampus. J Neurosci 2019; 39:9306-9315. [PMID: 31597723 DOI: 10.1523/jneurosci.1566-19.2019] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Revised: 10/02/2019] [Accepted: 10/03/2019] [Indexed: 02/06/2023] Open
Abstract
Mounting evidence suggests numerous glutamatergic synapse subtypes exist in the brain, and that these subtypes are likely defined by unique molecular regulatory mechanisms. Recent work has identified substantial divergence of molecular composition between commonly studied Schaffer collateral synapses and perforant path-dentate gyrus (DG) synapses of the hippocampus. However, little is known about the molecular mechanisms that may confer unique properties to perforant path-DG synapses. Here we investigate whether the RhoGEF (Rho guanine-nucleotide exchange factor) protein Tiam1 plays a unique role in the regulation of glutamatergic synapses in dentate granule neurons using a combination of molecular, electrophysiological, and imaging approaches in rat entorhino-hippocampal slices of both sexes. We find that inhibition of Tiam1 function in dentate granule neurons reduces synaptic AMPA receptor function and causes dendritic spines to adopt an elongated filopodia-like morphology. We also find that Tiam1's support of perforant path-DG synapse function is dependent on its GEF domain and identify a potential role for the auto-inhibitory PH domain of Tiam1 in regulating Tiam1 function at these synapses. In marked contrast, reduced Tiam1 expression in CA1 pyramidal neurons produced no effect on glutamatergic synapse development. Together, these data identify a critical role for Tiam1 in the hippocampus and reveal a unique Tiam1-mediated molecular program of glutamatergic synapse regulation in dentate granule neurons.SIGNIFICANCE STATEMENT Several lines of evidence independently point to the molecular diversity of glutamatergic synapses in the brain. Rho guanine-nucleotide exchange factor (RhoGEF) proteins as powerful modulators of glutamatergic synapse function have also become increasingly appreciated in recent years. Here we investigate the synaptic regulatory role of the RhoGEF protein Tiam1, whose expression appears to be remarkably enriched in granule neurons of the dentate gyrus. We find that Tiam1 plays a critical role in the development of glutamatergic perforant path-dentate gyrus synapses, but not in commonly studied in Schaffer collateral-CA1 synapses. Together, these data reveal a unique RhoGEF-mediated molecular program of glutamatergic synapse regulation in dentate granule neurons.
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29
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Richardson CE, Yee C, Shen K. A hormone receptor pathway cell-autonomously delays neuron morphological aging by suppressing endocytosis. PLoS Biol 2019; 17:e3000452. [PMID: 31589601 PMCID: PMC6797217 DOI: 10.1371/journal.pbio.3000452] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Revised: 10/17/2019] [Accepted: 09/05/2019] [Indexed: 01/12/2023] Open
Abstract
Neurons have a lifespan that parallels that of the organism and are largely irreplaceable. Their unusually long lifespan predisposes neurons to neurodegenerative disease. We sought to identify physiological mechanisms that delay neuron aging in Caenorhabditis elegans by asking how neuron morphological aging is arrested in the long-lived, alternate organismal state, the dauer diapause. We find that a hormone signaling pathway, the abnormal DAuer Formation (DAF) 12 nuclear hormone receptor (NHR) pathway, functions cell-intrinsically in the dauer diapause to arrest neuron morphological aging, and that same pathway can be cell-autonomously manipulated during normal organismal aging to delay neuron morphological aging. This delayed aging is mediated by suppressing constitutive endocytosis, which alters the subcellular localization of the actin regulator T cell lymphoma Invasion And Metastasis 1 (TIAM-1), thereby decreasing age-dependent neurite growth. Intriguingly, we show that suppressed endocytosis appears to be a general feature of cells in diapause, suggestive that this may be a mechanism to halt the growth and other age-related programs supported by most endosome recycling.
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Affiliation(s)
- Claire E. Richardson
- Department of Biology, Stanford University, Stanford, California, United States of America
| | - Callista Yee
- Department of Biology, Stanford University, Stanford, California, United States of America
| | - Kang Shen
- Department of Biology, Stanford University, Stanford, California, United States of America
- Howard Hughes Medical Institute, Department of Biology, Stanford University, Stanford, California, United States of America
- * E-mail:
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30
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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: 18] [Impact Index Per Article: 3.6] [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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31
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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: 29] [Impact Index Per Article: 5.8] [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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32
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Axon-Dependent Patterning and Maintenance of Somatosensory Dendritic Arbors. Dev Cell 2019; 48:229-244.e4. [PMID: 30661986 DOI: 10.1016/j.devcel.2018.12.015] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Revised: 11/12/2018] [Accepted: 12/16/2018] [Indexed: 12/20/2022]
Abstract
The mechanisms that pattern and maintain dendritic arbors are key to understanding the principles that govern nervous system assembly. The activity of presynaptic axons has long been known to shape dendrites, but activity-independent functions of axons in this process have remained elusive. Here, we show that in Caenorhabditis elegans, the axons of the ALA neuron control guidance and extension of the 1° dendrites of PVD somatosensory neurons independently of ALA activity. PVD 1° dendrites mimic ALA axon guidance defects in loss-of-function mutants for the extracellular matrix molecule MIG-6/Papilin or the UNC-6/Netrin pathway, suggesting that axon-dendrite adhesion is important for dendrite formation. We found that the SAX-7/L1CAM cell adhesion molecule engages in distinct molecular mechanisms to mediate extensions of PVD 1° dendrites and maintain the ALA-PVD axon-dendritic fascicle, respectively. Thus, axons can serve as critical scaffolds to pattern and maintain dendrites through contact-dependent but activity-independent mechanisms.
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