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Bustillo ME, Douthit J, Astigarraga S, Treisman JE. Two distinct mechanisms of Plexin A function in Drosophila optic lobe lamination and morphogenesis. Development 2024; 151:dev202237. [PMID: 38738602 PMCID: PMC11190435 DOI: 10.1242/dev.202237] [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: 08/06/2023] [Accepted: 04/28/2024] [Indexed: 05/14/2024]
Abstract
Visual circuit development is characterized by subdivision of neuropils into layers that house distinct sets of synaptic connections. We find that, in the Drosophila medulla, this layered organization depends on the axon guidance regulator Plexin A. In Plexin A null mutants, synaptic layers of the medulla neuropil and arborizations of individual neurons are wider and less distinct than in controls. Analysis of semaphorin function indicates that Semaphorin 1a, acting in a subset of medulla neurons, is the primary partner for Plexin A in medulla lamination. Removal of the cytoplasmic domain of endogenous Plexin A has little effect on the formation of medulla layers; however, both null and cytoplasmic domain deletion mutations of Plexin A result in an altered overall shape of the medulla neuropil. These data suggest that Plexin A acts as a receptor to mediate morphogenesis of the medulla neuropil, and as a ligand for Semaphorin 1a to subdivide it into layers. Its two independent functions illustrate how a few guidance molecules can organize complex brain structures by each playing multiple roles.
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Affiliation(s)
- Maria E. Bustillo
- Department of Cell Biology, New York University Grossman School of Medicine, 435 E. 30th Street, New York, NY 10016, USA
| | - Jessica Douthit
- Department of Cell Biology, New York University Grossman School of Medicine, 435 E. 30th Street, New York, NY 10016, USA
| | - Sergio Astigarraga
- Department of Cell Biology, New York University Grossman School of Medicine, 435 E. 30th Street, New York, NY 10016, USA
| | - Jessica E. Treisman
- Department of Cell Biology, New York University Grossman School of Medicine, 435 E. 30th Street, New York, NY 10016, USA
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2
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Kawashima R, Matsushita K, Mandai K, Sugita Y, Maruo T, Mizutani K, Midoh Y, Oguchi A, Murakawa Y, Kuniyoshi K, Sato R, Furukawa T, Nishida K, Takai Y. Necl-1/CADM3 regulates cone synapse formation in the mouse retina. iScience 2024; 27:109577. [PMID: 38623325 PMCID: PMC11016759 DOI: 10.1016/j.isci.2024.109577] [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: 09/19/2022] [Revised: 12/22/2023] [Accepted: 03/25/2024] [Indexed: 04/17/2024] Open
Abstract
In vertebrates, retinal neural circuitry for visual perception is organized in specific layers. The outer plexiform layer is the first synaptic region in the visual pathway, where photoreceptor synaptic terminals connect with bipolar and horizontal cell processes. However, molecular mechanisms underlying cone synapse formation to mediate OFF pathways remain unknown. This study reveals that Necl-1/CADM3 is localized at S- and S/M-opsin-containing cones and dendrites of type 4 OFF cone bipolar cells (CBCs). In Necl-1-/- mouse retina, synapses between cones and type 4 OFF CBCs were dislocated, horizontal cell distribution became abnormal, and α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors were dislocated. Necl-1-/- mice exhibited aberrant short-wavelength-light-elicited signal transmission from cones to OFF CBCs, which was rescued by AMPA receptor potentiator. Additionally, Necl-1-/- mice showed impaired optokinetic responses. These findings suggest that Necl-1 regulates cone synapse formation to mediate OFF cone pathways elicited by short-wavelength light in mouse retina.
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Affiliation(s)
- Rumi Kawashima
- Department of Ophthalmology, Osaka University Graduate School of Medicine, Suita, Osaka 565-0871, Japan
| | - Kenji Matsushita
- Department of Ophthalmology, Osaka University Graduate School of Medicine, Suita, Osaka 565-0871, Japan
| | - Kenji Mandai
- Division of Pathogenetic Signaling, Department of Biochemistry and Molecular Biology, Kobe University Graduate School of Medicine, Kobe, Hyogo 650-0047, Japan
- Department of Molecular and Cellular Neurobiology, Kitasato University Graduate School of Medical Sciences, Sagamihara, Kanagawa 252-0374, Japan
- Department of Biochemistry, Kitasato University School of Medicine, Sagamihara, Kanagawa 252-0374, Japan
| | - Yuko Sugita
- Laboratory for Molecular and Developmental Biology, Institute for Protein Research, Osaka University, Suita, Osaka 565-0871, Japan
| | - Tomohiko Maruo
- Division of Pathogenetic Signaling, Department of Biochemistry and Molecular Biology, Kobe University Graduate School of Medicine, Kobe, Hyogo 650-0047, Japan
- Department of Molecular and Cellular Neurobiology, Kitasato University Graduate School of Medical Sciences, Sagamihara, Kanagawa 252-0374, Japan
| | - Kiyohito Mizutani
- Division of Pathogenetic Signaling, Department of Biochemistry and Molecular Biology, Kobe University Graduate School of Medicine, Kobe, Hyogo 650-0047, Japan
- Division of Pathogenetic Signaling, Institute of Advanced Medical Sciences, Tokushima University, Tokushima 770-8503, Japan
| | - Yoshihiro Midoh
- Graduate School of Information Science and Technology, Osaka University, Suita, Osaka 565-0871, Japan
| | - Akiko Oguchi
- RIKEN-IFOM Joint Laboratory for Cancer Genomics, IMS RIKEN Center for Integrative Medical Sciences, Yokohama, Kanagawa 230-0045, Japan
| | - Yasuhiro Murakawa
- RIKEN-IFOM Joint Laboratory for Cancer Genomics, IMS RIKEN Center for Integrative Medical Sciences, Yokohama, Kanagawa 230-0045, Japan
| | - Kazuki Kuniyoshi
- Department of Ophthalmology, Kindai University Faculty of Medicine, Osakasayama, Osaka 589-8511, Japan
| | - Ryohei Sato
- Forefront Research Center for Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan
| | - Takahisa Furukawa
- Laboratory for Molecular and Developmental Biology, Institute for Protein Research, Osaka University, Suita, Osaka 565-0871, Japan
| | - Kohji Nishida
- Department of Ophthalmology, Osaka University Graduate School of Medicine, Suita, Osaka 565-0871, Japan
| | - Yoshimi Takai
- Division of Pathogenetic Signaling, Department of Biochemistry and Molecular Biology, Kobe University Graduate School of Medicine, Kobe, Hyogo 650-0047, Japan
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3
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Schmidt AR, Placer HJ, Muhammad IM, Shephard R, Patrick RL, Saurborn T, Horstick EJ, Bergeron SA. Transcriptional control of visual neural circuit development by GS homeobox 1. PLoS Genet 2024; 20:e1011139. [PMID: 38669217 PMCID: PMC11051655 DOI: 10.1371/journal.pgen.1011139] [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: 03/20/2023] [Accepted: 01/16/2024] [Indexed: 04/28/2024] Open
Abstract
As essential components of gene expression networks, transcription factors regulate neural circuit assembly. The homeobox transcription factor encoding gene, gs homeobox 1 (gsx1), is expressed in the developing visual system; however, no studies have examined its role in visual system formation. In zebrafish, retinal ganglion cell (RGC) axons that transmit visual information to the brain terminate in ten arborization fields (AFs) in the optic tectum (TeO), pretectum (Pr), and thalamus. Pretectal AFs (AF1-AF9) mediate distinct visual behaviors, yet we understand less about their development compared to AF10 in the TeO. Using gsx1 zebrafish mutants, immunohistochemistry, and transgenic lines, we observed that gsx1 is required for vesicular glutamate transporter, Tg(slc17a6b:DsRed), expression in the Pr, but not overall neuron number. gsx1 mutants have normal eye morphology, yet they exhibit impaired visual ability during prey capture. RGC axon volume in the gsx1 mutant Pr and TeO is reduced, and AF7 that is active during feeding is missing which is consistent with reduced hunting performance. Timed laser ablation of Tg(slc17a6b:DsRed)-positive cells reveals that they are necessary for AF7 formation. This work is the first to implicate gsx1 in establishing cell identity and functional neural circuits in the visual system.
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Affiliation(s)
- Alexandra R. Schmidt
- Department of Biology, West Virginia University, Morgantown, West Virgina, United States of America
| | - Haiden J. Placer
- Department of Biology, West Virginia University, Morgantown, West Virgina, United States of America
| | - Ishmael M. Muhammad
- Department of Biology, West Virginia University, Morgantown, West Virgina, United States of America
| | - Rebekah Shephard
- Department of Biology, West Virginia University, Morgantown, West Virgina, United States of America
| | - Regina L. Patrick
- Department of Biology, West Virginia University, Morgantown, West Virgina, United States of America
| | - Taylor Saurborn
- Department of Biology, West Virginia University, Morgantown, West Virgina, United States of America
| | - Eric J. Horstick
- Department of Biology, West Virginia University, Morgantown, West Virgina, United States of America
- Department of Neuroscience, West Virginia University, Morgantown, West Virgina, United States of America
| | - Sadie A. Bergeron
- Department of Biology, West Virginia University, Morgantown, West Virgina, United States of America
- Department of Neuroscience, West Virginia University, Morgantown, West Virgina, United States of America
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4
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Carrier Y, Rio LQ, Formicola N, de Sousa-Xavier V, Tabet M, Chen YCD, Wislez M, Orts L, Pinto-Teixeira F. Biased cell adhesion organizes a circuit for visual motion integration. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.11.571076. [PMID: 38168373 PMCID: PMC10760042 DOI: 10.1101/2023.12.11.571076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
Layer specific computations in the brain rely on neuronal processes establishing synaptic connections with specific partners in distinct laminae. In the Drosophila lobula plate neuropile, the axons of the four subtypes of T4 and T5 visual motion direction-selective neurons segregate into four layers, based on their directional preference, and form synapses with distinct subsets of postsynaptic neurons. Four bi-stratified inhibitory lobula plate intrinsic cells exhibit a consistent synaptic pattern, receiving excitatory T4/T5 inputs in one layer, and conveying inhibitory signals to an adjacent layer. This layered arrangement establishes motion opponency. Here, we identify layer-specific expression of different receptor-ligand pairs belonging to the Beat and Side families of Cell Adhesion Molecules (CAMs) between T4/T5 neurons and their postsynaptic partners. Genetic analysis reveals that Beat/Side mediated interactions are required to restrict T4/T5 axonal innervation to a single layer. We propose that Beat/Side contribute to synaptic specificity by biasing adhesion between synaptic partners before synaptogenesis.
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Affiliation(s)
- Yannick Carrier
- MCD, Centre de Biologie Intégrative (CBI), CNRS, Université de Toulouse, UT3, Toulouse, France
| | - Laura Quintana Rio
- MCD, Centre de Biologie Intégrative (CBI), CNRS, Université de Toulouse, UT3, Toulouse, France
| | - Nadia Formicola
- MCD, Centre de Biologie Intégrative (CBI), CNRS, Université de Toulouse, UT3, Toulouse, France
| | - Vicente de Sousa-Xavier
- MCD, Centre de Biologie Intégrative (CBI), CNRS, Université de Toulouse, UT3, Toulouse, France
| | - Maha Tabet
- MCD, Centre de Biologie Intégrative (CBI), CNRS, Université de Toulouse, UT3, Toulouse, France
| | | | - Maëva Wislez
- MCD, Centre de Biologie Intégrative (CBI), CNRS, Université de Toulouse, UT3, Toulouse, France
| | - Lisa Orts
- MCD, Centre de Biologie Intégrative (CBI), CNRS, Université de Toulouse, UT3, Toulouse, France
| | - Filipe Pinto-Teixeira
- MCD, Centre de Biologie Intégrative (CBI), CNRS, Université de Toulouse, UT3, Toulouse, France
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5
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Sherman S, Arnold-Ammer I, Schneider MW, Kawakami K, Baier H. Retina-derived signals control pace of neurogenesis in visual brain areas but not circuit assembly. Nat Commun 2023; 14:6020. [PMID: 37758715 PMCID: PMC10533834 DOI: 10.1038/s41467-023-40749-1] [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: 02/22/2023] [Accepted: 08/09/2023] [Indexed: 09/29/2023] Open
Abstract
Brain development is orchestrated by both innate and experience-dependent mechanisms, but their relative contributions are difficult to disentangle. Here we asked if and how central visual areas are altered in a vertebrate brain depleted of any and all signals from retinal ganglion cells throughout development. We transcriptionally profiled neurons in pretectum, thalamus and other retinorecipient areas of larval zebrafish and searched for changes in lakritz mutants that lack all retinal connections. Although individual genes are dysregulated, the complete set of 77 neuronal types develops in apparently normal proportions, at normal locations, and along normal differentiation trajectories. Strikingly, the cell-cycle exits of proliferating progenitors in these areas are delayed, and a greater fraction of early postmitotic precursors remain uncommitted or are diverted to a pre-glial fate. Optogenetic stimulation targeting groups of neurons normally involved in processing visual information evokes behaviors indistinguishable from wildtype. In conclusion, we show that signals emitted by retinal axons influence the pace of neurogenesis in visual brain areas, but do not detectably affect the specification or wiring of downstream neurons.
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Affiliation(s)
- Shachar Sherman
- Max Planck Institute for Biological Intelligence, Department Genes - Circuits - Behavior, Am Klopferspitz 18, 82152, Martinsried, Germany
| | - Irene Arnold-Ammer
- Max Planck Institute for Biological Intelligence, Department Genes - Circuits - Behavior, Am Klopferspitz 18, 82152, Martinsried, Germany
| | - Martin W Schneider
- Max Planck Institute for Biological Intelligence, Department Genes - Circuits - Behavior, Am Klopferspitz 18, 82152, Martinsried, Germany
| | - Koichi Kawakami
- Laboratory of Molecular and Developmental Biology, National Institute of Genetics, and Department of Genetics, SOKENDAI (The Graduate University for Advanced Studies), Mishima, Shizuoka, 411-8540, Japan
| | - Herwig Baier
- Max Planck Institute for Biological Intelligence, Department Genes - Circuits - Behavior, Am Klopferspitz 18, 82152, Martinsried, Germany.
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6
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Bustillo ME, Douthit J, Astigarraga S, Treisman JE. Two distinct mechanisms of Plexin A function in Drosophila optic lobe lamination and morphogenesis. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.07.552282. [PMID: 37609142 PMCID: PMC10441316 DOI: 10.1101/2023.08.07.552282] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/24/2023]
Abstract
Visual circuit development is characterized by subdivision of neuropils into layers that house distinct sets of synaptic connections. We find that in the Drosophila medulla, this layered organization depends on the axon guidance regulator Plexin A. In plexin A null mutants, synaptic layers of the medulla neuropil and arborizations of individual neurons are wider and less distinct than in controls. Analysis of Semaphorin function indicates that Semaphorin 1a, provided by cells that include Tm5 neurons, is the primary partner for Plexin A in medulla lamination. Removal of the cytoplasmic domain of endogenous Plexin A does not disrupt the formation of medulla layers; however, both null and cytoplasmic domain deletion mutations of plexin A result in an altered overall shape of the medulla neuropil. These data suggest that Plexin A acts as a receptor to mediate morphogenesis of the medulla neuropil, and as a ligand for Semaphorin 1a to subdivide it into layers. Its two independent functions illustrate how a few guidance molecules can organize complex brain structures by each playing multiple roles. Summary statement The axon guidance molecule Plexin A has two functions in Drosophila medulla development; morphogenesis of the neuropil requires its cytoplasmic domain, but establishing synaptic layers through Semaphorin 1a does not.
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7
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Kremers L, Sarieva K, Hoffmann F, Zhao Z, Ueffing M, Euler T, Nikić-Spiegel I, Schubert T. Super-resolution STED imaging in the inner and outer whole-mount mouse retina. FRONTIERS IN OPHTHALMOLOGY 2023; 3:1126338. [PMID: 38983015 PMCID: PMC11196978 DOI: 10.3389/fopht.2023.1126338] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/17/2022] [Accepted: 03/07/2023] [Indexed: 07/11/2024]
Abstract
Since its invention, super-resolution microscopy has become a popular tool for advanced imaging of biological structures, allowing visualisation of subcellular structures at a spatial scale below the diffraction limit. Thus, it is not surprising that recently, different super-resolution techniques are being applied in neuroscience, e.g. to resolve the clustering of neurotransmitter receptors and protein complex composition in presynaptic terminals. Still, the vast majority of these experiments were carried out either in cell cultures or very thin tissue sections, while there are only a few examples of super-resolution imaging in deeper layers (30 - 50 µm) of biological samples. In that context, the mammalian whole-mount retina has rarely been studied with super-resolution microscopy. Here, we aimed at establishing a stimulated-emission-depletion (STED) microscopy protocol for imaging whole-mount retina. To this end, we developed sample preparation including horizontal slicing of retinal tissue, an immunolabeling protocol with STED-compatible fluorophores and optimised the image acquisition settings. We labelled subcellular structures in somata, dendrites, and axons of retinal ganglion cells in the inner mouse retina. By measuring the full width at half maximum of the thinnest filamentous structures in our preparation, we achieved a resolution enhancement of two or higher compared to conventional confocal images. When combined with horizontal slicing of the retina, these settings allowed visualisation of putative GABAergic horizontal cell synapses in the outer retina. Taken together, we successfully established a STED protocol for reliable super-resolution imaging in the whole-mount mouse retina at depths between 30 and 50 µm, which enables investigating, for instance, protein complex composition and cytoskeletal ultrastructure at retinal synapses in health and disease.
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Affiliation(s)
- Leon Kremers
- Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany
- Werner Reichardt Centre for Integrative Neuroscience (CIN), University of Tübingen, Tübingen, Germany
- Institute for Experimental Epileptology and Cognition Research, University of Bonn, Bonn, Germany
- International Max Planck Research School for Brain and Behavior, Bonn, Germany
| | - Kseniia Sarieva
- Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany
- Werner Reichardt Centre for Integrative Neuroscience (CIN), University of Tübingen, Tübingen, Germany
- Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Felix Hoffmann
- Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany
| | - Zhijian Zhao
- Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany
| | - Marius Ueffing
- Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany
| | - Thomas Euler
- Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany
- Werner Reichardt Centre for Integrative Neuroscience (CIN), University of Tübingen, Tübingen, Germany
| | - Ivana Nikić-Spiegel
- Werner Reichardt Centre for Integrative Neuroscience (CIN), University of Tübingen, Tübingen, Germany
| | - Timm Schubert
- Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany
- Werner Reichardt Centre for Integrative Neuroscience (CIN), University of Tübingen, Tübingen, Germany
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8
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Guo YB, Liu YL, Chen QL, Liu G. Titanium oxide-based optoelectronic synapses with visual memory synergistically adjusted by internal emotions and ambient illumination. RSC Adv 2022; 12:27162-27169. [PMID: 36276034 PMCID: PMC9511690 DOI: 10.1039/d2ra02749f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2022] [Accepted: 09/11/2022] [Indexed: 11/23/2022] Open
Abstract
Brain-inspired neuromorphic computing has become one of the critical technologies to overcome the bottleneck of von Neumann architecture. It is a vital step to construct a brain-like neuromorphic computing system at the hardware level by utilizing artificial synaptic devices. Compared with electronic synaptic devices, optoelectronic synaptic devices have the advantages of low power consumption, low crosstalk, and high bandwidth. Artificial optoelectronic synapses, analogous to retinal structure, can directly respond to and process light signal information to mimic the neuromorphic visual system. As high-level nerve impulses, both generated and regulated, emotions affect the strength and persistence of memory. Ambient illumination can provide visual perception to distinguish the size, color, and other characteristics of objects as well as affect the nonvisual functions of individuals, such as emotional states, thereby affecting learning and memory function. Herein, an artificial optoelectronic synapse composed of ITO/TiO2−x/p-Si was proposed. A variety of biologically dependent synaptic plasticity relating to learning and memory, including short-term synaptic plasticity, long-term synaptic plasticity, and learning-forgetting-relearning multifunctional advanced synaptic activity, was successfully simulated. A 3 × 3 artificial optoelectronic synapse array based on 9 devices was constructed to mimic the functions of visual learning and memory affected by internal emotion and ambient illumination. The proposed artificial optoelectronic synapse will exhibit great potential in visual and image information perception and memory. A variety of biologically dependent synaptic plasticity activities were simulated on artificial optoelectronic synapse devices. An array was constructed to mimic the functions of visual learning and memory affected by internal emotion and ambient illumination.![]()
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Affiliation(s)
- Yan-bo Guo
- Department of Micro/Nano Electronics, School of Electronic Information and Electrical Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Yu-lin Liu
- School of Materials Science and Engineering, Xiangtan University, Xiangtan 411105, China
| | - Qi-lai Chen
- School of Materials, Sun Yat-sen University, Shenzhen, 518107, China
| | - Gang Liu
- Department of Micro/Nano Electronics, School of Electronic Information and Electrical Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China
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9
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Sengupta T, Koonce NL, Vázquez-Martínez N, Moyle MW, Duncan LH, Emerson SE, Han X, Shao L, Wu Y, Santella A, Fan L, Bao Z, Mohler W, Shroff H, Colón-Ramos DA. Differential adhesion regulates neurite placement via a retrograde zippering mechanism. eLife 2021; 10:71171. [PMID: 34783657 PMCID: PMC8843091 DOI: 10.7554/elife.71171] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Accepted: 11/15/2021] [Indexed: 11/13/2022] Open
Abstract
During development, neurites and synapses segregate into specific neighborhoods or layers within nerve bundles. The developmental programs guiding placement of neurites in specific layers, and hence their incorporation into specific circuits, are not well understood. We implement novel imaging methods and quantitative models to document the embryonic development of the C. elegans brain neuropil, and discover that differential adhesion mechanisms control precise placement of single neurites onto specific layers. Differential adhesion is orchestrated via developmentally-regulated expression of the IgCAM SYG-1, and its partner ligand SYG-2. Changes in SYG-1 expression across neuropil layers result in changes in adhesive forces, which sort SYG-2-expressing neurons. Sorting to layers occurs, not via outgrowth from the neurite tip, but via an alternate mechanism of retrograde zippering, involving interactions between neurite shafts. Our study indicates that biophysical principles from differential adhesion govern neurite placement and synaptic specificity in vivo in developing neuropil bundles.
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Affiliation(s)
- Titas Sengupta
- Yale University School of Medicine, New Haven, United States
| | - Noelle L Koonce
- Yale University School of Medicine, New Haven, United States
| | | | - Mark W Moyle
- Yale University School of Medicine, New Haven, United States
| | | | - Sarah E Emerson
- Yale University School of Medicine, New Haven, United States
| | - Xiaofei Han
- National Institutes of Health, Bethesda, United States
| | - Lin Shao
- Yale University School of Medicine, New Haven, United States
| | - Yicong Wu
- National Institutes of Health, Bethesda, United States
| | - Anthony Santella
- Developmental Biology Program, Molecular Cytology Core, Sloan-Kettering Institute, New York, United States
| | - Li Fan
- Helen and Robert Appel Alzheimer's Disease Institute, Weill Cornell Medicine, New York, United States
| | - Zhirong Bao
- Developmental Biology Program, Sloan-Kettering Institute, New York, United States
| | - William Mohler
- Department of Genetics and Developmental Biology, University of Connecticut Health Center, Farmington, United States
| | - Hari Shroff
- National Institutes of Health, Bethesda, United States
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10
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A cell-ECM mechanism for connecting the ipsilateral eye to the brain. Proc Natl Acad Sci U S A 2021; 118:2104343118. [PMID: 34654745 PMCID: PMC8545493 DOI: 10.1073/pnas.2104343118] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/24/2021] [Indexed: 12/11/2022] Open
Abstract
Distinct features of the visual world are transmitted from the retina to the brain through anatomically segregated circuits. Despite this being an organizing principle of visual pathways in mammals, we lack an understanding of the signaling mechanisms guiding axons of different types of retinal neurons into segregated layers of brain regions. We explore this question by identifying how axons from the ipsilateral retina innervate a specific lamina of the superior colliculus. Our studies reveal a unique cell–extracellular matrix recognition mechanism that specifies precise targeting of these axons to the superior colliculus. Loss of this mechanism not only resulted in the absence of this eye-specific visual circuit, but it led to an impairment of innate predatory visual behavior as well. Information about features in the visual world is parsed by circuits in the retina and is then transmitted to the brain by distinct subtypes of retinal ganglion cells (RGCs). Axons from RGC subtypes are stratified in retinorecipient brain nuclei, such as the superior colliculus (SC), to provide a segregated relay of parallel and feature-specific visual streams. Here, we sought to identify the molecular mechanisms that direct the stereotyped laminar targeting of these axons. We focused on ipsilateral-projecting subtypes of RGCs (ipsiRGCs) whose axons target a deep SC sublamina. We identified an extracellular glycoprotein, Nephronectin (NPNT), whose expression is restricted to this ipsiRGC-targeted sublamina. SC-derived NPNT and integrin receptors expressed by ipsiRGCs are both required for the targeting of ipsiRGC axons to the deep sublamina of SC. Thus, a cell–extracellular matrix (ECM) recognition mechanism specifies precise laminar targeting of ipsiRGC axons and the assembly of eye-specific parallel visual pathways.
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11
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Drosophila Fezf functions as a transcriptional repressor to direct layer-specific synaptic connectivity in the fly visual system. Proc Natl Acad Sci U S A 2021; 118:2025530118. [PMID: 33766917 PMCID: PMC8020669 DOI: 10.1073/pnas.2025530118] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Functionally relevant neuronal connections are often organized within discrete layers of neuropil to ensure proper connectivity and information processing. While layer-specific assembly of neuronal connectivity is a dynamic process involving stepwise interactions between different neuron types, the mechanisms underlying this critical developmental process are not well understood. Here, we investigate the role of the transcription factor dFezf in layer selection within the Drosophila visual system, which is important for synaptic specificity. Our findings show that dFezf functions as a transcriptional repressor governing the precise temporal expression pattern of downstream genes, including other transcription factors required for proper connectivity. Layer-specific assembly of neuronal connectivity in the fly visual system is thus orchestrated by precise, temporally controlled transcriptional cascades. The layered compartmentalization of synaptic connections, a common feature of nervous systems, underlies proper connectivity between neurons and enables parallel processing of neural information. However, the stepwise development of layered neuronal connections is not well understood. The medulla neuropil of the Drosophila visual system, which comprises 10 discrete layers (M1 to M10), where neural computations underlying distinct visual features are processed, serves as a model system for understanding layered synaptic connectivity. The first step in establishing layer-specific connectivity in the outer medulla (M1 to M6) is the innervation by lamina (L) neurons of one of two broad, primordial domains that will subsequently expand and transform into discrete layers. We previously found that the transcription factor dFezf cell-autonomously directs L3 lamina neurons to their proper primordial broad domain before they form synapses within the developing M3 layer. Here, we show that dFezf controls L3 broad domain selection through temporally precise transcriptional repression of the transcription factor slp1 (sloppy paired 1). In wild-type L3 neurons, slp1 is transiently expressed at a low level during broad domain selection. When dFezf is deleted, slp1 expression is up-regulated, and ablation of slp1 fully rescues the defect of broad domain selection in dFezf-null L3 neurons. Although the early, transient expression of slp1 is expendable for broad domain selection, it is surprisingly necessary for the subsequent L3 innervation of the M3 layer. DFezf thus functions as a transcriptional repressor to coordinate the temporal dynamics of a transcriptional cascade that orchestrates sequential steps of layer-specific synapse formation.
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12
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Structural and developmental principles of neuropil assembly in C. elegans. Nature 2021; 591:99-104. [PMID: 33627875 PMCID: PMC8385650 DOI: 10.1038/s41586-020-03169-5] [Citation(s) in RCA: 44] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Accepted: 11/12/2020] [Indexed: 01/31/2023]
Abstract
Neuropil is a fundamental form of tissue organization within the brain1, in which densely packed neurons synaptically interconnect into precise circuit architecture2,3. However, the structural and developmental principles that govern this nanoscale precision remain largely unknown4,5. Here we use an iterative data coarse-graining algorithm termed 'diffusion condensation'6 to identify nested circuit structures within the Caenorhabditis elegans neuropil, which is known as the nerve ring. We show that the nerve ring neuropil is largely organized into four strata that are composed of related behavioural circuits. The stratified architecture of the neuropil is a geometrical representation of the functional segregation of sensory information and motor outputs, with specific sensory organs and muscle quadrants mapping onto particular neuropil strata. We identify groups of neurons with unique morphologies that integrate information across strata and that create neural structures that cage the strata within the nerve ring. We use high resolution light-sheet microscopy7,8 coupled with lineage-tracing and cell-tracking algorithms9,10 to resolve the developmental sequence and reveal principles of cell position, migration and outgrowth that guide stratified neuropil organization. Our results uncover conserved structural design principles that underlie the architecture and function of the nerve ring neuropil, and reveal a temporal progression of outgrowth-based on pioneer neurons-that guides the hierarchical development of the layered neuropil. Our findings provide a systematic blueprint for using structural and developmental approaches to understand neuropil organization within the brain.
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13
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Dorskind JM, Kolodkin AL. Revisiting and refining roles of neural guidance cues in circuit assembly. Curr Opin Neurobiol 2021; 66:10-21. [PMID: 32823181 PMCID: PMC10725571 DOI: 10.1016/j.conb.2020.07.005] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Revised: 07/16/2020] [Accepted: 07/27/2020] [Indexed: 12/14/2022]
Abstract
Neural guidance mechanisms ensure the precise targeting and synaptogenesis events essential for normal circuit function. Neuronal growth cones encounter numerous attractive and repulsive cues as they navigate toward their intermediate and final targets; temporal and spatial regulation of these responses are critical for circuit assembly. Recent work highlights the complexity of these events throughout neural development and the multifaceted functions of a wide range of guidance cues. Here, we discuss recent studies that leverage advances in genetics, single cell tracing, transcriptomics and proteomics to further our understanding of the molecular mechanisms underlying neural guidance and overall circuit organization.
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Affiliation(s)
- Joelle M Dorskind
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
| | - Alex L Kolodkin
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
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14
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Barker AJ, Helmbrecht TO, Grob AA, Baier H. Functional, molecular and morphological heterogeneity of superficial interneurons in the larval zebrafish tectum. J Comp Neurol 2020; 529:2159-2175. [PMID: 33278028 DOI: 10.1002/cne.25082] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Revised: 11/27/2020] [Accepted: 11/30/2020] [Indexed: 11/08/2022]
Abstract
The superficial interneurons, SINs, of the zebrafish tectum, have been implicated in a range of visual functions, including size discrimination, directional selectivity, and looming-evoked escape. This raises the question if SIN subpopulations, despite their morphological similarities and shared anatomical position in the retinotectal processing stream, carry out diverse, task-specific functions in visual processing, or if they have simple tuning properties in common. Here we have further characterized the SINs through functional imaging, electrophysiological recordings, and neurotransmitter typing in two transgenic lines, the widely used Gal4s1156t and the recently reported LCRRH2-RH2-2:GFP. We found that about a third of the SINs strongly responded to changes in whole-field light levels, with a strong preference for OFF over ON stimuli. Interestingly, individual SINs were selectively tuned to a diverse range of narrow luminance decrements. Overall responses to whole-field luminance steps did not vary with the position of the SIN cell body along the depth of the tectal neuropil or with the orientation of its neurites. We ruled out the possibility that intrinsic photosensitivity of Gal4s1156t+ SINs contribute to the measured visual responses. We found that, while most SINs express GABAergic markers, a substantial minority express an excitatory neuronal marker, the vesicular glutamate transporter, expanding the possible roles of SIN function in the tectal circuitry. In conclusion, SINs represent a molecularly, morphologically, and functionally heterogeneous class of interneurons, with subpopulations that detect a range of specific visual features, to which we have now added narrow luminance decrements.
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Affiliation(s)
- Alison J Barker
- Department Genes-Circuits-Behavior, Max Planck Institute of Neurobiology, Munich, Germany
| | - Thomas O Helmbrecht
- Department Genes-Circuits-Behavior, Max Planck Institute of Neurobiology, Munich, Germany
| | - Aurélien A Grob
- Department Genes-Circuits-Behavior, Max Planck Institute of Neurobiology, Munich, Germany
| | - Herwig Baier
- Department Genes-Circuits-Behavior, Max Planck Institute of Neurobiology, Munich, Germany
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15
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Johnson KO, Triplett JW. Wiring subcortical image-forming centers: Topography, laminar targeting, and map alignment. Curr Top Dev Biol 2020; 142:283-317. [PMID: 33706920 DOI: 10.1016/bs.ctdb.2020.10.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
Efficient sensory processing is a complex and important function for species survival. As such, sensory circuits are highly organized to facilitate rapid detection of salient stimuli and initiate motor responses. For decades, the retina's projections to image-forming centers have served as useful models to elucidate the mechanisms by which such exquisite circuitry is wired. In this chapter, we review the roles of molecular cues, neuronal activity, and axon-axon competition in the development of topographically ordered retinal ganglion cell (RGC) projections to the superior colliculus (SC) and dorsal lateral geniculate nucleus (dLGN). Further, we discuss our current state of understanding regarding the laminar-specific targeting of subclasses of RGCs in the SC and its homolog, the optic tectum (OT). Finally, we cover recent studies examining the alignment of projections from primary visual cortex with RGCs that monitor the same region of space in the SC.
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Affiliation(s)
- Kristy O Johnson
- Center for Neuroscience Research, Children's National Research Institute, Washington, DC, United States; Institute for Biomedical Sciences, The George Washington University School of Medicine, Washington, DC, United States
| | - Jason W Triplett
- Center for Neuroscience Research, Children's National Research Institute, Washington, DC, United States; Department of Pediatrics, The George Washington University School of Medicine, Washington, DC, United States.
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16
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Förster D, Helmbrecht TO, Mearns DS, Jordan L, Mokayes N, Baier H. Retinotectal circuitry of larval zebrafish is adapted to detection and pursuit of prey. eLife 2020; 9:e58596. [PMID: 33044168 PMCID: PMC7550190 DOI: 10.7554/elife.58596] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Accepted: 09/07/2020] [Indexed: 12/22/2022] Open
Abstract
Retinal axon projections form a map of the visual environment in the tectum. A zebrafish larva typically detects a prey object in its peripheral visual field. As it turns and swims towards the prey, the stimulus enters the central, binocular area, and seemingly expands in size. By volumetric calcium imaging, we show that posterior tectal neurons, which serve to detect prey at a distance, tend to respond to small objects and intrinsically compute their direction of movement. Neurons in anterior tectum, where the prey image is represented shortly before the capture strike, are tuned to larger object sizes and are frequently not direction-selective, indicating that mainly interocular comparisons serve to compute an object's movement at close range. The tectal feature map originates from a linear combination of diverse, functionally specialized, lamina-specific, and topographically ordered retinal ganglion cell synaptic inputs. We conclude that local cell-type composition and connectivity across the tectum are adapted to the processing of location-dependent, behaviorally relevant object features.
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Affiliation(s)
- Dominique Förster
- Max Planck Institute of Neurobiology, Department Genes – Circuits – BehaviorMartinsriedGermany
| | - Thomas O Helmbrecht
- Max Planck Institute of Neurobiology, Department Genes – Circuits – BehaviorMartinsriedGermany
- Graduate School of Systemic Neurosciences, LMU BioCenterMartinsriedGermany
| | - Duncan S Mearns
- Max Planck Institute of Neurobiology, Department Genes – Circuits – BehaviorMartinsriedGermany
- Graduate School of Systemic Neurosciences, LMU BioCenterMartinsriedGermany
| | - Linda Jordan
- Max Planck Institute of Neurobiology, Department Genes – Circuits – BehaviorMartinsriedGermany
| | - Nouwar Mokayes
- Max Planck Institute of Neurobiology, Department Genes – Circuits – BehaviorMartinsriedGermany
| | - Herwig Baier
- Max Planck Institute of Neurobiology, Department Genes – Circuits – BehaviorMartinsriedGermany
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17
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Rangel Olguin AG, Rochon PL, Krishnaswamy A. New Optical Tools to Study Neural Circuit Assembly in the Retina. Front Neural Circuits 2020; 14:44. [PMID: 32848633 PMCID: PMC7424070 DOI: 10.3389/fncir.2020.00044] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2020] [Accepted: 06/23/2020] [Indexed: 12/17/2022] Open
Abstract
During development, neurons navigate a tangled thicket of thousands of axons and dendrites to synapse with just a few specific targets. This phenomenon termed wiring specificity, is critical to the assembly of neural circuits and the way neurons manage this feat is only now becoming clear. Recent studies in the mouse retina are shedding new insight into this process. They show that specific wiring arises through a series of stages that include: directed axonal and dendritic growth, the formation of neuropil layers, positioning of such layers, and matching of co-laminar synaptic partners. Each stage appears to be directed by a distinct family of recognition molecules, suggesting that the combinatorial expression of such family members might act as a blueprint for retinal connectivity. By reviewing the evidence in support of each stage, and by considering their underlying molecular mechanisms, we attempt to synthesize these results into a wiring model which generates testable predictions for future studies. Finally, we conclude by highlighting new optical methods that could be used to address such predictions and gain further insight into this fundamental process.
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18
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Xie X, Tabuchi M, Corver A, Duan G, Wu MN, Kolodkin AL. Semaphorin 2b Regulates Sleep-Circuit Formation in the Drosophila Central Brain. Neuron 2019; 104:322-337.e14. [PMID: 31564592 DOI: 10.1016/j.neuron.2019.07.019] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Revised: 05/09/2019] [Accepted: 07/14/2019] [Indexed: 11/29/2022]
Abstract
The fan-shaped body (FB) neuropil in the Drosophila brain central complex (CX) controls a variety of adult behaviors, including navigation and sleep. How neuronal processes are organized into precise layers and columns in the FB and how alterations in FB neural-circuit wiring affect animal behaviors are unknown. We report here that secreted semaphorin 2b (Sema-2b) acts through its transmembrane receptor Plexin B (PlexB) to locally attract neural processes to specific FB laminae. Aberrant Sema-2b/PlexB signaling leads to select disruptions in neural lamination, and these disruptions result in the formation of ectopic inhibitory connections between subsets of FB neurons. These structural alternations and connectivity defects are associated with changes in fly sleep and arousal, emphasizing the importance of lamination-mediated neural wiring in a central brain region critical for normal sleep behavior.
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Affiliation(s)
- Xiaojun Xie
- Children's Hospital, School of Medicine, Zhejiang University, Hangzhou 310029, China; Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Masashi Tabuchi
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Abel Corver
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Grace Duan
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Mark N Wu
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Alex L Kolodkin
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
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19
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Abstract
Visual stimuli can evoke complex behavioral responses, but the underlying streams of neural activity in mammalian brains are difficult to follow because of their size. Here, I review the visual system of zebrafish larvae, highlighting where recent experimental evidence has localized the functional steps of visuomotor transformations to specific brain areas. The retina of a larva encodes behaviorally relevant visual information in neural activity distributed across feature-selective ganglion cells such that signals representing distinct stimulus properties arrive in different areas or layers of the brain. Motor centers in the hindbrain encode motor variables that are precisely tuned to behavioral needs within a given stimulus setting. Owing to rapid technological progress, larval zebrafish provide unique opportunities for obtaining a comprehensive understanding of the intermediate processing steps occurring between visual and motor centers, revealing how visuomotor transformations are implemented in a vertebrate brain.
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Affiliation(s)
- Johann H. Bollmann
- Developmental Biology, Institute of Biology I, Faculty of Biology, and Bernstein Center Freiburg, University of Freiburg, 79104 Freiburg, Germany
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20
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Xu C, Theisen E, Maloney R, Peng J, Santiago I, Yapp C, Werkhoven Z, Rumbaut E, Shum B, Tarnogorska D, Borycz J, Tan L, Courgeon M, Griffin T, Levin R, Meinertzhagen IA, de Bivort B, Drugowitsch J, Pecot MY. Control of Synaptic Specificity by Establishing a Relative Preference for Synaptic Partners. Neuron 2019; 103:865-877.e7. [PMID: 31300277 PMCID: PMC6728174 DOI: 10.1016/j.neuron.2019.06.006] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2018] [Revised: 04/19/2019] [Accepted: 06/11/2019] [Indexed: 02/07/2023]
Abstract
The ability of neurons to identify correct synaptic partners is fundamental to the proper assembly and function of neural circuits. Relative to other steps in circuit formation such as axon guidance, our knowledge of how synaptic partner selection is regulated is severely limited. Drosophila Dpr and DIP immunoglobulin superfamily (IgSF) cell-surface proteins bind heterophilically and are expressed in a complementary manner between synaptic partners in the visual system. Here, we show that in the lamina, DIP mis-expression is sufficient to promote synapse formation with Dpr-expressing neurons and that disrupting DIP function results in ectopic synapse formation. These findings indicate that DIP proteins promote synapses to form between specific cell types and that in their absence, neurons synapse with alternative partners. We propose that neurons have the capacity to synapse with a broad range of cell types and that synaptic specificity is achieved by establishing a preference for specific partners.
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Affiliation(s)
- Chundi Xu
- Department of Neurobiology, Harvard Medical School, 220 Longwood Ave, Boston, MA 02115, USA.
| | - Emma Theisen
- Department of Neurobiology, Harvard Medical School, 220 Longwood Ave, Boston, MA 02115, USA
| | - Ryan Maloney
- Department of Neurobiology, Harvard Medical School, 220 Longwood Ave, Boston, MA 02115, USA
| | - Jing Peng
- Department of Neurobiology, Harvard Medical School, 220 Longwood Ave, Boston, MA 02115, USA
| | - Ivan Santiago
- Department of Neurobiology, Harvard Medical School, 220 Longwood Ave, Boston, MA 02115, USA
| | - Clarence Yapp
- Image and Data Analysis Core, Harvard Medical School, Boston, MA 02115, USA
| | - Zachary Werkhoven
- Center for Brain Science and Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA 02138, USA
| | - Elijah Rumbaut
- Department of Neurobiology, Harvard Medical School, 220 Longwood Ave, Boston, MA 02115, USA
| | - Bryan Shum
- Department of Neurobiology, Harvard Medical School, 220 Longwood Ave, Boston, MA 02115, USA
| | - Dorota Tarnogorska
- Department of Psychology and Neuroscience, Life Sciences Centre, Dalhousie University, Halifax, NS B3H 4R2, Canada
| | - Jolanta Borycz
- Department of Psychology and Neuroscience, Life Sciences Centre, Dalhousie University, Halifax, NS B3H 4R2, Canada
| | - Liming Tan
- Department of Biological Chemistry, HHMI, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Maximilien Courgeon
- Department of Biology, New York University, 100 Washington Square East, New York, NY 10003, USA
| | - Tessa Griffin
- Department of Neurobiology, Harvard Medical School, 220 Longwood Ave, Boston, MA 02115, USA
| | - Raina Levin
- Department of Neurobiology, Harvard Medical School, 220 Longwood Ave, Boston, MA 02115, USA
| | - Ian A Meinertzhagen
- Department of Psychology and Neuroscience, Life Sciences Centre, Dalhousie University, Halifax, NS B3H 4R2, Canada
| | - Benjamin de Bivort
- Center for Brain Science and Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA 02138, USA
| | - Jan Drugowitsch
- Department of Neurobiology, Harvard Medical School, 220 Longwood Ave, Boston, MA 02115, USA
| | - Matthew Y Pecot
- Department of Neurobiology, Harvard Medical School, 220 Longwood Ave, Boston, MA 02115, USA.
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21
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Kujawski S, Sonawane M, Knust E. penner/lgl2 is required for the integrity of the photoreceptor layer in the zebrafish retina. Biol Open 2019; 8:8/4/bio041830. [PMID: 31015218 PMCID: PMC6503998 DOI: 10.1242/bio.041830] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The vertebrate retina is a complex tissue built from multiple neuronal cell types, which develop from a pseudostratified neuroepithelium. These cells are arranged into a highly organized and stereotypic pattern formed by nuclear and plexiform layers. The process of lamination as well as the maturation and differentiation of photoreceptor cells rely on the establishment and maintenance of apico-basal cell polarity and formation of adhesive junctions. Defects in any of these processes can result in impaired vision and are causally related to a variety of human diseases leading to blindness. While the importance of apical polarity regulators in retinal stratification and disease is well established, little is known about the function of basal regulators in retinal development. Here, we analyzed the role of Lgl2, a basolateral polarity factor, in the zebrafish retina. Lgl2 is upregulated in photoreceptor cells and in the retinal pigment epithelium by 72 h post fertilization. In both cell types, Lgl2 is localized basolaterally. Loss of zygotic Lgl2 does not interfere with retinal lamination or photoreceptor cell polarity or maturation. However, knockdown of both maternal and zygotic Lgl2 leads to impaired cell adhesion. As a consequence, severe layering defects occur in the distal retina, manifested by a breakdown of the outer plexiform layer and the outer limiting membrane. These results define zebrafish Lgl2 as an important regulator of retinal lamination, which, given the high degree of evolutionary conservation, may be preserved in other vertebrates, including human. Summary: Knockdown of penner/lgl2 leads to a breakdown of the outer plexiform layer and the outer limiting membrane in the zebrafish retina due to impaired cell adhesion.
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Affiliation(s)
- Satu Kujawski
- Max-Planck-Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108 01307 Dresden, Germany
| | - Mahendra Sonawane
- Tata Institute of Fundamental Research, Department of Biological Sciences, Homi Bhabha Road, Navy Nagar, Colaba, Mumbai 400005, India
| | - Elisabeth Knust
- Max-Planck-Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108 01307 Dresden, Germany
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22
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Liu J, Reggiani JDS, Laboulaye MA, Pandey S, Chen B, Rubenstein JLR, Krishnaswamy A, Sanes JR. Tbr1 instructs laminar patterning of retinal ganglion cell dendrites. Nat Neurosci 2018; 21:659-670. [PMID: 29632360 PMCID: PMC5920715 DOI: 10.1038/s41593-018-0127-z] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2018] [Accepted: 02/20/2018] [Indexed: 12/20/2022]
Abstract
Visual information is delivered to the brain by >40 types of retinal ganglion cells (RGCs). Diversity in this representation arises within the inner plexiform layer (IPL), where dendrites of each RGC type are restricted to specific sublaminae, limiting the interneuronal types that can innervate them. How such dendritic restriction arises is unclear. We show that the transcription factor Tbr1 is expressed by four mouse RGC types with dendrites in the outer IPL and is required for their laminar specification. Loss of Tbr1 results in elaboration of dendrites within the inner IPL, while misexpression in other cells retargets their neurites to the outer IPL. Two transmembrane molecules, Sorcs3 and Cdh8, act as effectors of the Tbr1-controlled lamination program. However, they are expressed in just one Tbr1+ RGC type, supporting a model in which a single transcription factor implements similar laminar choices in distinct cell types by recruiting partially non-overlapping effectors.
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Affiliation(s)
- Jinyue Liu
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA, USA.,Center for Brain Science, Harvard University, Cambridge, MA, USA.,Program in Neuroscience, Harvard Medical School, Boston, MA, USA
| | - Jasmine D S Reggiani
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA, USA.,Center for Brain Science, Harvard University, Cambridge, MA, USA
| | - Mallory A Laboulaye
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA, USA.,Center for Brain Science, Harvard University, Cambridge, MA, USA
| | - Shristi Pandey
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA, USA.,Center for Brain Science, Harvard University, Cambridge, MA, USA
| | - Bin Chen
- Department of Molecular, Cell and Developmental Biology, University of California at Santa Cruz, Santa Cruz, CA, USA
| | - John L R Rubenstein
- Department of Psychiatry, University of California at San Francisco, San Francisco, CA, USA
| | - Arjun Krishnaswamy
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA, USA.,Center for Brain Science, Harvard University, Cambridge, MA, USA.,Department of Physiology, McGill University, Montreal, QC, Canada
| | - Joshua R Sanes
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA, USA. .,Center for Brain Science, Harvard University, Cambridge, MA, USA.
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23
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Ray TA, Roy S, Kozlowski C, Wang J, Cafaro J, Hulbert SW, Wright CV, Field GD, Kay JN. Formation of retinal direction-selective circuitry initiated by starburst amacrine cell homotypic contact. eLife 2018; 7:e34241. [PMID: 29611808 PMCID: PMC5931800 DOI: 10.7554/elife.34241] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2017] [Accepted: 03/29/2018] [Indexed: 12/23/2022] Open
Abstract
A common strategy by which developing neurons locate their synaptic partners is through projections to circuit-specific neuropil sublayers. Once established, sublayers serve as a substrate for selective synapse formation, but how sublayers arise during neurodevelopment remains unknown. Here, we identify the earliest events that initiate formation of the direction-selective circuit in the inner plexiform layer of mouse retina. We demonstrate that radially migrating newborn starburst amacrine cells establish homotypic contacts on arrival at the inner retina. These contacts, mediated by the cell-surface protein MEGF10, trigger neuropil innervation resulting in generation of two sublayers comprising starburst-cell dendrites. This dendritic scaffold then recruits projections from circuit partners. Abolishing MEGF10-mediated contacts profoundly delays and ultimately disrupts sublayer formation, leading to broader direction tuning and weaker direction-selectivity in retinal ganglion cells. Our findings reveal a mechanism by which differentiating neurons transition from migratory to mature morphology, and highlight this mechanism's importance in forming circuit-specific sublayers.
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Affiliation(s)
- Thomas A Ray
- Department of NeurobiologyDuke University School of MedicineDurhamUnited States
- Department of OphthalmologyDuke University School of MedicineDurhamUnited States
| | - Suva Roy
- Department of NeurobiologyDuke University School of MedicineDurhamUnited States
| | - Christopher Kozlowski
- Department of NeurobiologyDuke University School of MedicineDurhamUnited States
- Department of OphthalmologyDuke University School of MedicineDurhamUnited States
| | - Jingjing Wang
- Department of NeurobiologyDuke University School of MedicineDurhamUnited States
- Department of OphthalmologyDuke University School of MedicineDurhamUnited States
| | - Jon Cafaro
- Department of NeurobiologyDuke University School of MedicineDurhamUnited States
| | - Samuel W Hulbert
- Department of NeurobiologyDuke University School of MedicineDurhamUnited States
| | - Christopher V Wright
- Department of Cell and Developmental BiologyVanderbilt University School of MedicineNashvilleUnited States
| | - Greg D Field
- Department of NeurobiologyDuke University School of MedicineDurhamUnited States
| | - Jeremy N Kay
- Department of NeurobiologyDuke University School of MedicineDurhamUnited States
- Department of OphthalmologyDuke University School of MedicineDurhamUnited States
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24
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Peng J, Santiago IJ, Ahn C, Gur B, Tsui CK, Su Z, Xu C, Karakhanyan A, Silies M, Pecot MY. Drosophila Fezf coordinates laminar-specific connectivity through cell-intrinsic and cell-extrinsic mechanisms. eLife 2018. [PMID: 29513217 PMCID: PMC5854465 DOI: 10.7554/elife.33962] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Laminar arrangement of neural connections is a fundamental feature of neural circuit organization. Identifying mechanisms that coordinate neural connections within correct layers is thus vital for understanding how neural circuits are assembled. In the medulla of the Drosophila visual system neurons form connections within ten parallel layers. The M3 layer receives input from two neuron types that sequentially innervate M3 during development. Here we show that M3-specific innervation by both neurons is coordinated by Drosophila Fezf (dFezf), a conserved transcription factor that is selectively expressed by the earlier targeting input neuron. In this cell, dFezf instructs layer specificity and activates the expression of a secreted molecule (Netrin) that regulates the layer specificity of the other input neuron. We propose that employment of transcriptional modules that cell-intrinsically target neurons to specific layers, and cell-extrinsically recruit other neurons is a general mechanism for building layered networks of neural connections.
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Affiliation(s)
- Jing Peng
- Department of Neurobiology, Harvard Medical School, Boston, United States
| | - Ivan J Santiago
- Department of Neurobiology, Harvard Medical School, Boston, United States
| | - Curie Ahn
- Department of Neurobiology, Harvard Medical School, Boston, United States
| | - Burak Gur
- European Neuroscience Institute, Göttingen, Germany
| | - C Kimberly Tsui
- Department of Genetics, Stanford University, Stanford, United States
| | - Zhixiao Su
- Department of Neurobiology, Harvard Medical School, Boston, United States
| | - Chundi Xu
- Department of Neurobiology, Harvard Medical School, Boston, United States
| | - Aziz Karakhanyan
- Department of Neurobiology, Harvard Medical School, Boston, United States
| | | | - Matthew Y Pecot
- Department of Neurobiology, Harvard Medical School, Boston, United States
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25
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Abstract
Semaphorins are extracellular signaling proteins that are essential for the development and maintenance of many organs and tissues. The more than 20-member semaphorin protein family includes secreted, transmembrane and cell surface-attached proteins with diverse structures, each characterized by a single cysteine-rich extracellular sema domain, the defining feature of the family. Early studies revealed that semaphorins function as axon guidance molecules, but it is now understood that semaphorins are key regulators of morphology and motility in many different cell types including those that make up the nervous, cardiovascular, immune, endocrine, hepatic, renal, reproductive, respiratory and musculoskeletal systems, as well as in cancer cells. Semaphorin signaling occurs predominantly through Plexin receptors and results in changes to the cytoskeletal and adhesive machinery that regulate cellular morphology. While much remains to be learned about the mechanisms underlying the effects of semaphorins, exciting work has begun to reveal how semaphorin signaling is fine-tuned through different receptor complexes and other mechanisms to achieve specific outcomes in various cellular contexts and physiological systems. These and future studies will lead to a more complete understanding of semaphorin-mediated development and to a greater understanding of how these proteins function in human disease.
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Affiliation(s)
- Laura Taylor Alto
- Departments of Neuroscience and Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Jonathan R Terman
- Departments of Neuroscience and Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA.
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26
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Di Donato V, De Santis F, Albadri S, Auer TO, Duroure K, Charpentier M, Concordet JP, Gebhardt C, Del Bene F. An Attractive Reelin Gradient Establishes Synaptic Lamination in the Vertebrate Visual System. Neuron 2018; 97:1049-1062.e6. [PMID: 29429939 DOI: 10.1016/j.neuron.2018.01.030] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2016] [Revised: 11/11/2017] [Accepted: 01/11/2018] [Indexed: 10/18/2022]
Abstract
A conserved organizational and functional principle of neural networks is the segregation of axon-dendritic synaptic connections into laminae. Here we report that targeting of synaptic laminae by retinal ganglion cell (RGC) arbors in the vertebrate visual system is regulated by a signaling system relying on target-derived Reelin and VLDLR/Dab1a on the projecting neurons. Furthermore, we find that Reelin is distributed as a gradient on the target tissue and stabilized by heparan sulfate proteoglycans (HSPGs) in the extracellular matrix (ECM). Through genetic manipulations, we show that this Reelin gradient is important for laminar targeting and that it is attractive for RGC axons. Finally, we suggest a comprehensive model of synaptic lamina formation in which attractive Reelin counter-balances repulsive Slit1, thereby guiding RGC axons toward single synaptic laminae. We establish a mechanism that may represent a general principle for neural network assembly in vertebrate species and across different brain areas.
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Affiliation(s)
- Vincenzo Di Donato
- Institut Curie, PSL Research University, INSERM U934, CNRS UMR3215, UPMC Paris-Sorbonne, Paris 75005, France
| | - Flavia De Santis
- Institut Curie, PSL Research University, INSERM U934, CNRS UMR3215, UPMC Paris-Sorbonne, Paris 75005, France
| | - Shahad Albadri
- Institut Curie, PSL Research University, INSERM U934, CNRS UMR3215, UPMC Paris-Sorbonne, Paris 75005, France
| | - Thomas Oliver Auer
- Institut Curie, PSL Research University, INSERM U934, CNRS UMR3215, UPMC Paris-Sorbonne, Paris 75005, France
| | - Karine Duroure
- Institut Curie, PSL Research University, INSERM U934, CNRS UMR3215, UPMC Paris-Sorbonne, Paris 75005, France
| | - Marine Charpentier
- Muséum National d'Histoire Naturelle, INSERM U1154, CNRS UMR7196, Paris 75231, France
| | - Jean-Paul Concordet
- Muséum National d'Histoire Naturelle, INSERM U1154, CNRS UMR7196, Paris 75231, France
| | - Christoph Gebhardt
- Institut Curie, PSL Research University, INSERM U934, CNRS UMR3215, UPMC Paris-Sorbonne, Paris 75005, France.
| | - Filippo Del Bene
- Institut Curie, PSL Research University, INSERM U934, CNRS UMR3215, UPMC Paris-Sorbonne, Paris 75005, France.
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27
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Yan Q, Zhai L, Zhang B, Dallman JE. Spatial patterning of excitatory and inhibitory neuropil territories during spinal circuit development. J Comp Neurol 2017; 525:1649-1667. [PMID: 27997694 DOI: 10.1002/cne.24152] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2016] [Revised: 10/13/2016] [Accepted: 11/14/2016] [Indexed: 01/04/2023]
Abstract
To generate rhythmic motor behaviors, both single neurons and neural circuits require a balance between excitatory inputs that trigger action potentials and inhibitory inputs that promote a stable resting potential (E/I balance). Previous studies have focused on individual neurons and have shown that, over a short spatial scale, excitatory and inhibitory (E/I) synapses tend to form structured territories with inhibitory inputs enriched on cell bodies and proximal dendrites and excitatory inputs on distal dendrites. However, systems-level E/I patterns, at spatial scales larger than single neurons, are largely uncharted. We used immunostaining for PSD-95 and gephyrin postsynaptic scaffolding proteins as proxies for excitatory and inhibitory synapses, respectively, to quantify the numbers and map the distributions of E/I synapses in zebrafish spinal cord at both an embryonic stage and a larval stage. At the embryonic stage, we found that PSD-95 puncta outnumber gephyrin puncta, with the number of gephyrin puncta increasing to match that of PSD-95 puncta at the larval stage. At both stages, PSD-95 puncta are enriched in the most lateral neuropil corresponding to distal dendrites while gephyrin puncta are enriched on neuronal somata and in the medial neuropil. Significantly, similar to synaptic puncta, neuronal processes also exhibit medial-lateral territories at both developmental stages with enrichment of glutamatergic (excitatory) processes laterally and glycinergic (inhibitory) processes medially. This establishment of neuropil excitatory-inhibitory structure largely precedes dendritic arborization of primary motor neurons, suggesting that the structured neuropil could provide a framework for the development of E/I balance at the cellular level. J. Comp. Neurol. 525:1649-1667, 2017. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Qing Yan
- Department of Biology, Cox Science Center, University of Miami, 1301 Memorial Drive, Coral Gables, Florida
| | - Lu Zhai
- Department of Biology, Cox Science Center, University of Miami, 1301 Memorial Drive, Coral Gables, Florida
| | - Bo Zhang
- Department of Biology, Cox Science Center, University of Miami, 1301 Memorial Drive, Coral Gables, Florida
| | - Julia E Dallman
- Department of Biology, Cox Science Center, University of Miami, 1301 Memorial Drive, Coral Gables, Florida
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28
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Ngo KT, Andrade I, Hartenstein V. Spatio-temporal pattern of neuronal differentiation in the Drosophila visual system: A user's guide to the dynamic morphology of the developing optic lobe. Dev Biol 2017; 428:1-24. [PMID: 28533086 PMCID: PMC5825191 DOI: 10.1016/j.ydbio.2017.05.008] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2017] [Revised: 05/08/2017] [Accepted: 05/09/2017] [Indexed: 11/20/2022]
Abstract
Visual information processing in animals with large image forming eyes is carried out in highly structured retinotopically ordered neuropils. Visual neuropils in Drosophila form the optic lobe, which consists of four serially arranged major subdivisions; the lamina, medulla, lobula and lobula plate; the latter three of these are further subdivided into multiple layers. The visual neuropils are formed by more than 100 different cell types, distributed and interconnected in an invariant highly regular pattern. This pattern relies on a protracted sequence of developmental steps, whereby different cell types are born at specific time points and nerve connections are formed in a tightly controlled sequence that has to be coordinated among the different visual neuropils. The developing fly visual system has become a highly regarded and widely studied paradigm to investigate the genetic mechanisms that control the formation of neural circuits. However, these studies are often made difficult by the complex and shifting patterns in which different types of neurons and their connections are distributed throughout development. In the present paper we have reconstructed the three-dimensional architecture of the Drosophila optic lobe from the early larva to the adult. Based on specific markers, we were able to distinguish the populations of progenitors of the four optic neuropils and map the neurons and their connections. Our paper presents sets of annotated confocal z-projections and animated 3D digital models of these structures for representative stages. The data reveal the temporally coordinated growth of the optic neuropils, and clarify how the position and orientation of the neuropils and interconnecting tracts (inner and outer optic chiasm) changes over time. Finally, we have analyzed the emergence of the discrete layers of the medulla and lobula complex using the same markers (DN-cadherin, Brp) employed to systematically explore the structure and development of the central brain neuropil. Our work will facilitate experimental studies of the molecular mechanisms regulating neuronal fate and connectivity in the fly visual system, which bears many fundamental similarities with the retina of vertebrates.
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Affiliation(s)
- Kathy T Ngo
- Department of Molecular, Cell, and Developmental Biology, United States
| | - Ingrid Andrade
- Department of Molecular, Cell, and Developmental Biology, United States
| | - Volker Hartenstein
- Department of Molecular, Cell, and Developmental Biology, United States; Molecular Biology Institute, University of California, Los Angeles, Los Angeles, CA, United States.
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29
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Abstract
Although much is known about the regenerative capacity of retinal ganglion cells, very significant barriers remain in our ability to restore visual function following traumatic injury or disease-induced degeneration. Here we summarize our current understanding of the factors regulating axon guidance and target engagement in regenerating axons, and review the state of the field of neural regeneration, focusing on the visual system and highlighting studies using other model systems that can inform analysis of visual system regeneration. This overview is motivated by a Society for Neuroscience Satellite meeting, "Reconnecting Neurons in the Visual System," held in October 2015 sponsored by the National Eye Institute as part of their "Audacious Goals Initiative" and co-organized by Carol Mason (Columbia University) and Michael Crair (Yale University). The collective wisdom of the conference participants pointed to important gaps in our knowledge and barriers to progress in promoting the restoration of visual system function. This article is thus a summary of our existing understanding of visual system regeneration and provides a blueprint for future progress in the field.
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30
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Xie X, Tabuchi M, Brown MP, Mitchell SP, Wu MN, Kolodkin AL. The laminar organization of the Drosophila ellipsoid body is semaphorin-dependent and prevents the formation of ectopic synaptic connections. eLife 2017. [PMID: 28632130 PMCID: PMC5511011 DOI: 10.7554/elife.25328] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
The ellipsoid body (EB) in the Drosophila brain is a central complex (CX) substructure that harbors circumferentially laminated ring (R) neuron axons and mediates multifaceted sensory integration and motor coordination functions. However, what regulates R axon lamination and how lamination affects R neuron function remain unknown. We show here that the EB is sequentially innervated by small-field and large-field neurons and that early developing EB neurons play an important regulatory role in EB laminae formation. The transmembrane proteins semaphorin-1a (Sema-1a) and plexin A function together to regulate R axon lamination. R neurons recruit both GABA and GABA-A receptors to their axon terminals in the EB, and optogenetic stimulation coupled with electrophysiological recordings show that Sema-1a-dependent R axon lamination is required for preventing the spread of synaptic inhibition between adjacent EB lamina. These results provide direct evidence that EB lamination is critical for local pre-synaptic inhibitory circuit organization. DOI:http://dx.doi.org/10.7554/eLife.25328.001 The human brain contains around one hundred billion nerve cells, or neurons, which are interconnected and organized into distinct layers within different brain regions. Electrical impulses pass along a cable-like part of each neuron, known as the axon, to reach other neurons in different layers of various brain structures. The brain of a fruit fly contains fewer neurons – about 100 thousand in total – but it still establishes precise connections among neurons in different brain layers. In both flies and humans, axons grow along set paths to reach their targets by following guidance cues. Many of these cues are conserved between insects and mammals, including proteins belonging to the semaphorin family. These proteins work together to steer growing axons towards their proper targets and repel them away from the incorrect ones. However, how neurons establish connections in specific layers remains poorly understood. In the middle of the fruit fly brain lies a donut-shaped structure called the ellipsoid body, which the fly needs to navigate the world around it. The ellipsoid body contains a group of neurons that extend their axons to form multiple concentric rings. Xie et al. have now asked how the different “ring neurons” are organized in the ellipsoid body and how this sort of organization affects the connections between the neurons. Imaging techniques were used to visualize the layered organization of different ring neurons and to track their growing axons. Further work showed that this organization depends on semaphorin signaling, because when this pathway was disrupted, the layered pattern did not develop properly. This in turn, caused the axons of the ring neuron to wander out of their correct concentric ring and connect with the wrong targets in adjacent rings. Together these findings show that neurons rely on evolutionarily conserved semaphorins to correctly organize themselves into layers and connect with the appropriate targets. Further work is now needed to identify additional proteins that are critical for fly brains to form layered structures, and to understand how this layered organization influences how an animal behaves. DOI:http://dx.doi.org/10.7554/eLife.25328.002
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Affiliation(s)
- Xiaojun Xie
- The Solomon H. Snyder Department of Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, United States.,Howard Hughes Medical Institute, The Johns Hopkins University School of Medicine, Baltimore, United States
| | - Masashi Tabuchi
- Department of Neurology, The Johns Hopkins University School of Medicine, Baltimore, United States
| | - Matthew P Brown
- The Solomon H. Snyder Department of Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, United States.,Howard Hughes Medical Institute, The Johns Hopkins University School of Medicine, Baltimore, United States
| | - Sarah P Mitchell
- The Solomon H. Snyder Department of Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, United States.,Howard Hughes Medical Institute, The Johns Hopkins University School of Medicine, Baltimore, United States
| | - Mark N Wu
- The Solomon H. Snyder Department of Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, United States.,Department of Neurology, The Johns Hopkins University School of Medicine, Baltimore, United States
| | - Alex L Kolodkin
- The Solomon H. Snyder Department of Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, United States.,Howard Hughes Medical Institute, The Johns Hopkins University School of Medicine, Baltimore, United States
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31
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Wang J, O’Sullivan ML, Mukherjee D, Puñal VM, Farsiu S, Kay JN. Anatomy and spatial organization of Müller glia in mouse retina. J Comp Neurol 2017; 525:1759-1777. [PMID: 27997986 PMCID: PMC5542564 DOI: 10.1002/cne.24153] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Revised: 10/17/2016] [Accepted: 11/08/2016] [Indexed: 12/15/2022]
Abstract
Müller glia, the most abundant glia of vertebrate retina, have an elaborate morphology characterized by a vertical stalk that spans the retina and branches in each retinal layer. Müller glia play diverse, critical roles in retinal homeostasis, which are presumably enabled by their complex anatomy. However, much remains unknown, particularly in mouse, about the anatomical arrangement of Müller cells and their arbors, and how these features arise in development. Here we use membrane-targeted fluorescent proteins to reveal the fine structure of mouse Müller arbors. We find sublayer-specific arbor specializations within the inner plexiform layer (IPL) that occur consistently at defined laminar locations. We then characterize Müller glia spatial patterning, revealing how individual cells collaborate to form a pan-retinal network. Müller cells, unlike neurons, are spread across the retina with homogenous density, and their arbor sizes change little with eccentricity. Using Brainbow methods to label neighboring cells in different colors, we find that Müller glia tile retinal space with minimal overlap. The shape of their arbors is irregular but nonrandom, suggesting that local interactions between neighboring cells determine their territories. Finally, we identify a developmental window at postnatal Days 6 to 9 when Müller arbors first colonize the synaptic layers beginning in stereotyped inner plexiform layer sublaminae. Together, our study defines the anatomical arrangement of mouse Müller glia and their network in the radial and tangential planes of the retina, in development and adulthood. The local precision of Müller glia organization suggests that their morphology is sculpted by specific cell to cell interactions with neurons and each other.
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Affiliation(s)
- Jingjing Wang
- Department of Neurobiology, Duke University School of Medicine, Durham, NC,
USA
- Program in Cell and Molecular Biology, Duke University School of Medicine,
Durham, NC, USA
| | - Matthew L. O’Sullivan
- Department of Neurobiology, Duke University School of Medicine, Durham, NC,
USA
- Department of Ophthalmology, Duke University School of Medicine, Durham, NC,
USA
| | - Dibyendu Mukherjee
- Department of Ophthalmology, Duke University School of Medicine, Durham, NC,
USA
- Department of Biomedical Engineering, Duke University, Durham, NC, USA
| | - Vanessa M. Puñal
- Department of Neurobiology, Duke University School of Medicine, Durham, NC,
USA
- Department of Ophthalmology, Duke University School of Medicine, Durham, NC,
USA
| | - Sina Farsiu
- Department of Ophthalmology, Duke University School of Medicine, Durham, NC,
USA
- Department of Biomedical Engineering, Duke University, Durham, NC, USA
| | - Jeremy N. Kay
- Department of Neurobiology, Duke University School of Medicine, Durham, NC,
USA
- Department of Ophthalmology, Duke University School of Medicine, Durham, NC,
USA
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32
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Zhang C, Kolodkin AL, Wong RO, James RE. Establishing Wiring Specificity in Visual System Circuits: From the Retina to the Brain. Annu Rev Neurosci 2017; 40:395-424. [PMID: 28460185 DOI: 10.1146/annurev-neuro-072116-031607] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The retina is a tremendously complex image processor, containing numerous cell types that form microcircuits encoding different aspects of the visual scene. Each microcircuit exhibits a distinct pattern of synaptic connectivity. The developmental mechanisms responsible for this patterning are just beginning to be revealed. Furthermore, signals processed by different retinal circuits are relayed to specific, often distinct, brain regions. Thus, much work has focused on understanding the mechanisms that wire retinal axonal projections to their appropriate central targets. Here, we highlight recently discovered cellular and molecular mechanisms that together shape stereotypic wiring patterns along the visual pathway, from within the retina to the brain. Although some mechanisms are common across circuits, others play unconventional and circuit-specific roles. Indeed, the highly organized connectivity of the visual system has greatly facilitated the discovery of novel mechanisms that establish precise synaptic connections within the nervous system.
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Affiliation(s)
- Chi Zhang
- Department of Biological Structure, University of Washington, Seattle, Washington 98195; ,
| | - Alex L Kolodkin
- Solomon H. Snyder Department of Neuroscience, Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205; ,
| | - Rachel O Wong
- Department of Biological Structure, University of Washington, Seattle, Washington 98195; ,
| | - Rebecca E James
- Solomon H. Snyder Department of Neuroscience, Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205; ,
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33
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Kolodkin AL, Hiesinger PR. Wiring visual systems: common and divergent mechanisms and principles. Curr Opin Neurobiol 2017; 42:128-135. [PMID: 28064004 PMCID: PMC5316370 DOI: 10.1016/j.conb.2016.12.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2016] [Revised: 12/16/2016] [Accepted: 12/16/2016] [Indexed: 10/20/2022]
Abstract
The study of visual systems has a rich history, leading to the discovery and understanding of basic principles underlying the elaboration of neuronal connectivity. Recent work in model organisms such as fly, fish and mouse has yielded a wealth of new insights into visual system wiring. Here, we consider how axonal and dendritic patterning in columns and laminae influence synaptic partner selection in these model organisms. We highlight similarities and differences among disparate visual systems with the goal of identifying common and divergent principles for visual system wiring.
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Affiliation(s)
- Alex L Kolodkin
- The Solomon H. Snyder Department of Neuroscience and Howard Hughes Medical Institute, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
| | - P Robin Hiesinger
- Division of Neurobiology of the Institute for Biology, Free University Berlin, Germany.
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34
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Herget U, Gutierrez-Triana JA, Salazar Thula O, Knerr B, Ryu S. Single-Cell Reconstruction of Oxytocinergic Neurons Reveals Separate Hypophysiotropic and Encephalotropic Subtypes in Larval Zebrafish. eNeuro 2017; 4:ENEURO.0278-16.2016. [PMID: 28317020 PMCID: PMC5356222 DOI: 10.1523/eneuro.0278-16.2016] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2016] [Revised: 11/24/2016] [Accepted: 12/14/2016] [Indexed: 11/21/2022] Open
Abstract
Oxytocin regulates a diverse set of processes including stress, analgesia, metabolism, and social behavior. How such diverse functions are mediated by a single hormonal system is not well understood. Different functions of oxytocin could be mediated by distinct cell groups, yet it is currently unknown whether different oxytocinergic cell types exist that specifically mediate peripheral neuroendocrine or various central neuromodulatory processes via dedicated pathways. Using the Brainbow technique to map the morphology and projections of individual oxytocinergic cells in the larval zebrafish brain, we report here the existence of two main types of oxytocinergic cells: those that innervate the pituitary and those that innervate diverse brain regions. Similar to the situation in the adult rat and the adult midshipman, but in contrast to the situation in the adult trout, these two cell types are mutually exclusive and can be distinguished based on morphological and anatomical criteria. Further, our results reveal that complex oxytocinergic innervation patterns are already established in the larval zebrafish brain.
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Affiliation(s)
- Ulrich Herget
- Developmental Genetics of the Nervous System, Max Planck Institute for Medical Research, 69120 Heidelberg, Germany
| | - Jose Arturo Gutierrez-Triana
- Developmental Genetics of the Nervous System, Max Planck Institute for Medical Research, 69120 Heidelberg, Germany
| | - Oriana Salazar Thula
- Developmental Genetics of the Nervous System, Max Planck Institute for Medical Research, 69120 Heidelberg, Germany
| | - Boris Knerr
- Developmental Genetics of the Nervous System, Max Planck Institute for Medical Research, 69120 Heidelberg, Germany
| | - Soojin Ryu
- Developmental Genetics of the Nervous System, Max Planck Institute for Medical Research, 69120 Heidelberg, Germany
- Focus Program Translational Neuroscience, University Medical Center, Johannes Gutenberg University Mainz, Langenbeckstr. 1, 55131, Mainz, Germany
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35
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Hamodi AS, Liu Z, Pratt KG. An NMDA receptor-dependent mechanism for subcellular segregation of sensory inputs in the tadpole optic tectum. eLife 2016; 5. [PMID: 27879199 PMCID: PMC5135393 DOI: 10.7554/elife.20502] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2016] [Accepted: 11/22/2016] [Indexed: 11/25/2022] Open
Abstract
In the vertebrate CNS, afferent sensory inputs are targeted to specific depths or layers of their target neuropil. This patterning exists ab initio, from the very beginning, and therefore has been considered an activity-independent process. However, here we report that, during circuit development, the subcellular segregation of the visual and mechanosensory inputs to specific regions of tectal neuron dendrites in the tadpole optic tectum requires NMDA receptor activity. Blocking NMDARs during the formation of these sensory circuits, or removing the visual set of inputs, leads to less defined segregation, and suggests a correlation-based mechanism in which correlated inputs wire to common regions of dendrites. This can account for how two sets of inputs form synapses onto different regions of the same dendrite. Blocking NMDA receptors during later stages of circuit development did not disrupt segregation, indicating a critical period for activity-dependent shaping of patterns of innervation. DOI:http://dx.doi.org/10.7554/eLife.20502.001
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Affiliation(s)
- Ali S Hamodi
- Department of Zoology and Physiology and Program in Neuroscience, University of Wyoming, Laramie, United States
| | - Zhenyu Liu
- Department of Zoology and Physiology and Program in Neuroscience, University of Wyoming, Laramie, United States
| | - Kara G Pratt
- Department of Zoology and Physiology and Program in Neuroscience, University of Wyoming, Laramie, United States
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36
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Abstract
The most striking structure in the nervous system is the complex yet stereotyped morphology of the neuronal dendritic tree. Dendritic morphologies and the connections they make govern information flow and integration in the brain. The fundamental mechanisms that regulate dendritic outgrowth and branching are subjects of extensive study. In this review, we summarize recent advances in the molecular and cellular mechanisms for routing dendrites in layers and columns, prevalent organizational structures in the brain. We highlight how dendritic patterning influences the formation of synaptic circuits.
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Affiliation(s)
- Jiangnan Luo
- a Section on Neuronal Connectivity, Cell Biology and Neurobiology Branch, Eunice Kennedy Shriver National Institute of Child Health and Human Development , Bethesda , MD , USA
| | - Philip G McQueen
- b Mathematical and Statistical Computing Laboratory, Office of Intramural Research, Center for Information Technology , National Institutes of Health , Bethesda , MD , USA
| | - Bo Shi
- a Section on Neuronal Connectivity, Cell Biology and Neurobiology Branch, Eunice Kennedy Shriver National Institute of Child Health and Human Development , Bethesda , MD , USA ;,c Biological Sciences Graduate Program, College of Computer, Mathematical, and Natural Sciences , University of Maryland , College Park , MD , USA
| | - Chi-Hon Lee
- a Section on Neuronal Connectivity, Cell Biology and Neurobiology Branch, Eunice Kennedy Shriver National Institute of Child Health and Human Development , Bethesda , MD , USA
| | - Chun-Yuan Ting
- a Section on Neuronal Connectivity, Cell Biology and Neurobiology Branch, Eunice Kennedy Shriver National Institute of Child Health and Human Development , Bethesda , MD , USA
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37
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de Wit J, Ghosh A. Specification of synaptic connectivity by cell surface interactions. Nat Rev Neurosci 2015; 17:22-35. [PMID: 26656254 DOI: 10.1038/nrn.2015.3] [Citation(s) in RCA: 192] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The molecular diversification of cell surface molecules has long been postulated to impart specific surface identities on neuronal cell types. The existence of unique cell surface identities would allow neurons to distinguish one another and connect with their appropriate target cells. Although progress has been made in identifying cell type-specific surface molecule repertoires and in characterizing their extracellular interactions, determining how this molecular diversity contributes to the precise wiring of neural circuitry has proven challenging. Here, we review the role of the cadherin, neurexin, immunoglobulin and leucine-rich repeat protein superfamilies in the specification of connectivity. The emerging evidence suggests that the concerted actions of these proteins may critically contribute to the assembly of neural circuits.
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Affiliation(s)
- Joris de Wit
- VIB Center for the Biology of Disease and Center for Human Genetics, KU Leuven, Herestraat 49, 3000 Leuven, Belgium
| | - Anirvan Ghosh
- Neuroscience Discovery, Roche Innovation Center Basel, F. Hoffman-La Roche, Grenzacherstrasse 124, 4070 Basel, Switzerland
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Nikolaou N, Meyer MP. Lamination Speeds the Functional Development of Visual Circuits. Neuron 2015; 88:999-1013. [PMID: 26607001 PMCID: PMC4674658 DOI: 10.1016/j.neuron.2015.10.020] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Revised: 09/17/2015] [Accepted: 10/08/2015] [Indexed: 12/05/2022]
Abstract
A common feature of the brain is the arrangement of synapses in layers. To examine the significance of this organizational feature, we studied the functional development of direction-selective (DS) circuits in the tectum of astray mutant zebrafish in which lamination of retinal ganglion cell (RGC) axons is lost. We show that although never laminar, the tuning of DS-RGC axons targeting the mutant tectum is normal. Analysis of mutant tectal neurons at late developmental stages reveals that directional tuning is indistinguishable from wild-type larvae. Furthermore, we show that structural plasticity of tectal dendrites and RGC axons compensates for the loss of lamination, establishing connectivity between DS-RGCs and their normal tectal targets. However, tectal direction selectivity is severely perturbed at earlier developmental stages. Thus, the formation of synaptic laminae is ultimately dispensable for the correct wiring of direction-selective tectal circuits, but it is crucial for the rapid assembly of these networks. Video Abstract
Robo2 directs lamination of direction-selective retinal axons and tectal dendrites Tectal lamination is required for rapid assembly of direction-selective circuits Functional direction-selective circuits eventually form when lamination is lost Structural plasticity compensates for the loss of tectal lamination
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Affiliation(s)
- Nikolas Nikolaou
- MRC Centre for Developmental Neurobiology, King's College London, Guy's Hospital Campus, London, SE1 1UL, UK.
| | - Martin P Meyer
- MRC Centre for Developmental Neurobiology, King's College London, Guy's Hospital Campus, London, SE1 1UL, UK.
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Abstract
The nervous system is populated by numerous types of neurons, each bearing a dendritic arbor with a characteristic morphology. These type-specific features influence many aspects of a neuron's function, including the number and identity of presynaptic inputs and how inputs are integrated to determine firing properties. Here, we review the mechanisms that regulate the construction of cell type-specific dendrite patterns during development. We focus on four aspects of dendrite patterning that are particularly important in determining the function of the mature neuron: (a) dendrite shape, including branching pattern and geometry of the arbor; (b) dendritic arbor size;
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Affiliation(s)
| | - Joshua R Sanes
- Center for Brain Science and Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts 02138;
| | - Jeremy N Kay
- Departments of Neurobiology and Ophthalmology, Duke University School of Medicine, Durham, North Carolina 27710;
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Abstract
Different types of retinal ganglion cells (RGCs) project to distinct brain targets. In this issue of Neuron, Osterhout et al. (2015) and Sun et al. (2015) identify how direction-selective RGC axons match with their targets and the consequences for visual function when targeting is impaired.
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Entchev EV, Patel DS, Zhan M, Steele AJ, Lu H, Ch'ng Q. A gene-expression-based neural code for food abundance that modulates lifespan. eLife 2015; 4:e06259. [PMID: 25962853 PMCID: PMC4417936 DOI: 10.7554/elife.06259] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2014] [Accepted: 04/03/2015] [Indexed: 12/18/2022] Open
Abstract
How the nervous system internally represents environmental food availability is poorly understood. Here, we show that quantitative information about food abundance is encoded by combinatorial neuron-specific gene-expression of conserved TGFβ and serotonin pathway components in Caenorhabditis elegans. Crosstalk and auto-regulation between these pathways alters the shape, dynamic range, and population variance of the gene-expression responses of daf-7 (TGFβ) and tph-1 (tryptophan hydroxylase) to food availability. These intricate regulatory features provide distinct mechanisms for TGFβ and serotonin signaling to tune the accuracy of this multi-neuron code: daf-7 primarily regulates gene-expression variability, while tph-1 primarily regulates the dynamic range of gene-expression responses. This code is functional because daf-7 and tph-1 mutations bidirectionally attenuate food level-dependent changes in lifespan. Our results reveal a neural code for food abundance and demonstrate that gene expression serves as an additional layer of information processing in the nervous system to control long-term physiology. DOI:http://dx.doi.org/10.7554/eLife.06259.001 To maximize their chances of survival, animals need to be able to sense changes in the abundance of food in their environment and respond in an appropriate manner. The nervous system is able to sense cues from the environment and coordinate responses in the whole organism, but it is not clear how this leads to long-term changes in the organism's biology. In nematode worms, two genes called daf-7 and tph-1 appear to be involved in connecting the sensing of food availability with changes in the biology of the organism. The daf-7 gene encodes a hormone, while tph-1 encodes an enzyme that makes a neurochemical called serotonin. Here, Entchev, Patel, Zhan et al. found that daf-7 and tph-1 genes are active in three pairs of neurons in nematode worms. The experiments show that these neurons collectively form a circuit that carries information about the abundance of food, which leads to changes in how long the worms live. When this circuit was disrupted by removing these genes, the worms' ability to adjust their lifespan in response to changes in the availability of food was weakened, likely because they were unable to sense food. The experiments also show that the circuit regulates itself, largely because daf-7 and tph-1 are able to control each-other's activity. Together, these results suggest that changing the activity of certain genes in neurons enables nematode worms to alter their biology in response to changes in the availability of food. Neurons in the brain use electrical activity to communicate and process information and Entchev, Patel, Zhan et al.'s findings imply that gene activity can also perform a similar role. DOI:http://dx.doi.org/10.7554/eLife.06259.002
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Affiliation(s)
- Eugeni V Entchev
- MRC Centre for Developmental Neurobiology, King's College London, London, United Kingdom
| | - Dhaval S Patel
- MRC Centre for Developmental Neurobiology, King's College London, London, United Kingdom
| | - Mei Zhan
- Interdisciplinary Bioengineering Graduate Program, Georgia Institute of Technology, Atlanta, United States
| | - Andrew J Steele
- MRC Centre for Developmental Neurobiology, King's College London, London, United Kingdom
| | - Hang Lu
- Interdisciplinary Bioengineering Graduate Program, Georgia Institute of Technology, Atlanta, United States
| | - QueeLim Ch'ng
- MRC Centre for Developmental Neurobiology, King's College London, London, United Kingdom
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Contactin-4 mediates axon-target specificity and functional development of the accessory optic system. Neuron 2015; 86:985-999. [PMID: 25959733 DOI: 10.1016/j.neuron.2015.04.005] [Citation(s) in RCA: 81] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2014] [Revised: 02/19/2015] [Accepted: 03/31/2015] [Indexed: 12/31/2022]
Abstract
The mammalian eye-to-brain pathway includes more than 20 parallel circuits, each consisting of precise long-range connections between specific sets of retinal ganglion cells (RGCs) and target structures in the brain. The mechanisms that drive assembly of these parallel connections and the functional implications of their specificity remain unresolved. Here we show that in the absence of contactin 4 (CNTN4) or one of its binding partners, amyloid precursor protein (APP), a subset of direction-selective RGCs fail to target the nucleus of the optic tract (NOT)--the accessory optic system (AOS) target controlling horizontal image stabilization. Conversely, ectopic expression of CNTN4 biases RGCs to arborize in the NOT, and that process also requires APP. Our data reveal critical and novel roles for CNTN4/APP in promoting target-specific axon arborization, and they highlight the importance of this process for functional development of a behaviorally relevant parallel visual pathway.
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Missaire M, Hindges R. The role of cell adhesion molecules in visual circuit formation: from neurite outgrowth to maps and synaptic specificity. Dev Neurobiol 2015; 75:569-83. [PMID: 25649254 PMCID: PMC4855686 DOI: 10.1002/dneu.22267] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2014] [Revised: 01/08/2015] [Accepted: 01/09/2015] [Indexed: 11/08/2022]
Abstract
The formation of visual circuitry is a multistep process that involves cell–cell interactions based on a range of molecular mechanisms. The correct implementation of individual events, including axon outgrowth and guidance, the formation of the topographic map, or the synaptic targeting of specific cellular subtypes, are prerequisites for a fully functional visual system that is able to appropriately process the information captured by the eyes. Cell adhesion molecules (CAMs) with their adhesive properties and their high functional diversity have been identified as key actors in several of these fundamental processes. Because of their growth‐promoting properties, CAMs play an important role in neuritogenesis. Furthermore, they are necessary to control additional neurite development, regulating dendritic spacing and axon pathfinding. Finally, trans‐synaptic interactions of CAMs ensure cell type‐specific connectivity as a basis for the establishment of circuits processing distinct visual features. Recent discoveries implicating CAMs in novel mechanisms have led to a better general understanding of neural circuit formation, but also revealed an increasing complexity of their function. This review aims at describing the different levels of action for CAMs to shape neural connectivity, with a special focus on the visual system. © 2015 Wiley Periodicals, Inc. Develop Neurobiol 75: 569–583, 2015
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Affiliation(s)
- Mégane Missaire
- MRC Centre for Developmental Neurobiology, King's College London, New Hunt's House, Guy's Campus, London SE1 1UL, United Kingdom
| | - Robert Hindges
- MRC Centre for Developmental Neurobiology, King's College London, New Hunt's House, Guy's Campus, London SE1 1UL, United Kingdom
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Schmidt ERE, Brignani S, Adolfs Y, Lemstra S, Demmers J, Vidaki M, Donahoo ALS, Lilleväli K, Vasar E, Richards LJ, Karagogeos D, Kolk SM, Pasterkamp RJ. Subdomain-mediated axon-axon signaling and chemoattraction cooperate to regulate afferent innervation of the lateral habenula. Neuron 2014; 83:372-387. [PMID: 25033181 DOI: 10.1016/j.neuron.2014.05.036] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/21/2014] [Indexed: 11/20/2022]
Abstract
A dominant feature of neural circuitry is the organization of neuronal projections and synapses into specific brain nuclei or laminae. Lamina-specific connectivity is controlled by the selective expression of extracellular guidance and adhesion molecules in the target field. However, how (sub)nucleus-specific connections are established and whether axon-derived cues contribute to subdomain targeting are largely unknown. Here, we demonstrate that the lateral subnucleus of the habenula (lHb) determines its own afferent innervation by sending out efferent projections that express the cell adhesion molecule LAMP to reciprocally collect and guide dopaminergic afferents to the lHb-a phenomenon we term subdomain-mediated axon-axon signaling. This process of reciprocal axon-axon interactions cooperates with lHb-specific chemoattraction mediated by Netrin-1, which controls axon target entry, to ensure specific innervation of the lHb. We propose that cooperation between pretarget reciprocal axon-axon signaling and subdomain-restricted instructive cues provides a highly precise and general mechanism to establish subdomain-specific neural circuitry.
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Affiliation(s)
- Ewoud Roberto Eduard Schmidt
- Department of Translational Neuroscience, Brain Center Rudolf Magnus, University Medical Center Utrecht, Universiteitsweg 100, 3584 CG Utrecht, the Netherlands
| | - Sara Brignani
- Department of Translational Neuroscience, Brain Center Rudolf Magnus, University Medical Center Utrecht, Universiteitsweg 100, 3584 CG Utrecht, the Netherlands
| | - Youri Adolfs
- Department of Translational Neuroscience, Brain Center Rudolf Magnus, University Medical Center Utrecht, Universiteitsweg 100, 3584 CG Utrecht, the Netherlands
| | - Suzanne Lemstra
- Department of Translational Neuroscience, Brain Center Rudolf Magnus, University Medical Center Utrecht, Universiteitsweg 100, 3584 CG Utrecht, the Netherlands
| | - Jeroen Demmers
- Proteomics Centre and Department of Cell Biology, Erasmus University Medical Centre, Dr Molewaterplein 50, 3015 GE Rotterdam, the Netherlands
| | - Marina Vidaki
- Department of Basic Science, Faculty of Medicine, University of Crete and Institute of Molecular Biology and Biotechnology, Vassilika Vouton, Heraklion GR-7110, Greece
| | - Amber-Lee Skye Donahoo
- Queensland Brain Institute and The School of Biomedical Sciences, University of Queensland, Building 79, St Lucia Campus, Brisbane, QLD 4067, Australia
| | - Kersti Lilleväli
- Department of Physiology, Institute of Biomedicine and Translational Medicine, University of Tartu, Ravila 19, 50411 Tartu, Estonia
| | - Eero Vasar
- Department of Physiology, Institute of Biomedicine and Translational Medicine, University of Tartu, Ravila 19, 50411 Tartu, Estonia
| | - Linda Jane Richards
- Queensland Brain Institute and The School of Biomedical Sciences, University of Queensland, Building 79, St Lucia Campus, Brisbane, QLD 4067, Australia
| | - Domna Karagogeos
- Department of Basic Science, Faculty of Medicine, University of Crete and Institute of Molecular Biology and Biotechnology, Vassilika Vouton, Heraklion GR-7110, Greece
| | - Sharon Margriet Kolk
- Department of Translational Neuroscience, Brain Center Rudolf Magnus, University Medical Center Utrecht, Universiteitsweg 100, 3584 CG Utrecht, the Netherlands
| | - Ronald Jeroen Pasterkamp
- Department of Translational Neuroscience, Brain Center Rudolf Magnus, University Medical Center Utrecht, Universiteitsweg 100, 3584 CG Utrecht, the Netherlands.
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