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Baeriswyl T, Dumoulin A, Schaettin M, Tsapara G, Niederkofler V, Helbling D, Avilés E, Frei JA, Wilson NH, Gesemann M, Kunz B, Stoeckli ET. Endoglycan plays a role in axon guidance by modulating cell adhesion. eLife 2021; 10:64767. [PMID: 33650489 PMCID: PMC7946425 DOI: 10.7554/elife.64767] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Accepted: 02/25/2021] [Indexed: 01/27/2023] Open
Abstract
Axon navigation depends on the interactions between guidance molecules along the trajectory and specific receptors on the growth cone. However, our in vitro and in vivo studies on the role of Endoglycan demonstrate that in addition to specific guidance cue – receptor interactions, axon guidance depends on fine-tuning of cell-cell adhesion. Endoglycan, a sialomucin, plays a role in axon guidance in the central nervous system of chicken embryos, but it is neither an axon guidance cue nor a receptor. Rather, Endoglycan acts as a negative regulator of molecular interactions based on evidence from in vitro experiments demonstrating reduced adhesion of growth cones. In the absence of Endoglycan, commissural axons fail to properly navigate the midline of the spinal cord. Taken together, our in vivo and in vitro results support the hypothesis that Endoglycan acts as a negative regulator of cell-cell adhesion in commissural axon guidance.
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Affiliation(s)
- Thomas Baeriswyl
- Department of Molecular Life Sciences and Neuroscience Center Zurich, University of Zurich, Zurich, Switzerland
| | - Alexandre Dumoulin
- Department of Molecular Life Sciences and Neuroscience Center Zurich, University of Zurich, Zurich, Switzerland
| | - Martina Schaettin
- Department of Molecular Life Sciences and Neuroscience Center Zurich, University of Zurich, Zurich, Switzerland
| | - Georgia Tsapara
- Department of Molecular Life Sciences and Neuroscience Center Zurich, University of Zurich, Zurich, Switzerland
| | - Vera Niederkofler
- Department of Molecular Life Sciences and Neuroscience Center Zurich, University of Zurich, Zurich, Switzerland
| | - Denise Helbling
- Department of Molecular Life Sciences and Neuroscience Center Zurich, University of Zurich, Zurich, Switzerland
| | - Evelyn Avilés
- Department of Molecular Life Sciences and Neuroscience Center Zurich, University of Zurich, Zurich, Switzerland
| | - Jeannine A Frei
- Department of Molecular Life Sciences and Neuroscience Center Zurich, University of Zurich, Zurich, Switzerland
| | - Nicole H Wilson
- Department of Molecular Life Sciences and Neuroscience Center Zurich, University of Zurich, Zurich, Switzerland
| | - Matthias Gesemann
- Department of Molecular Life Sciences and Neuroscience Center Zurich, University of Zurich, Zurich, Switzerland
| | - Beat Kunz
- Department of Molecular Life Sciences and Neuroscience Center Zurich, University of Zurich, Zurich, Switzerland
| | - Esther T Stoeckli
- Department of Molecular Life Sciences and Neuroscience Center Zurich, University of Zurich, Zurich, Switzerland
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Clinical and experimental evidence suggest a link between KIF7 and C5orf42-related ciliopathies through Sonic Hedgehog signaling. Eur J Hum Genet 2018; 26:197-209. [PMID: 29321670 PMCID: PMC5839020 DOI: 10.1038/s41431-017-0019-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2017] [Revised: 09/11/2017] [Accepted: 09/19/2017] [Indexed: 01/03/2023] Open
Abstract
Acrocallosal syndrome (ACLS) is an autosomal recessive neurodevelopmental disorder caused by KIF7 defects and belongs to the heterogeneous group of ciliopathies related to Joubert syndrome (JBTS). While ACLS is characterized by macrocephaly, prominent forehead, depressed nasal bridge, and hypertelorism, facial dysmorphism has not been emphasized in JBTS cohorts with molecular diagnosis. To evaluate the specificity and etiology of ACLS craniofacial features, we performed whole exome or targeted Sanger sequencing in patients with the aforementioned overlapping craniofacial appearance but variable additional ciliopathy features followed by functional studies. We found (likely) pathogenic variants of KIF7 in 5 out of 9 families, including the original ACLS patients, and delineated 1000 to 4000-year-old Swiss founder alleles. Three of the remaining families had (likely) pathogenic variants in the JBTS gene C5orf42, and one patient had a novel de novo frameshift variant in SHH known to cause autosomal dominant holoprosencephaly. In accordance with the patients' craniofacial anomalies, we showed facial midline widening after silencing of C5orf42 in chicken embryos. We further supported the link between KIF7, SHH, and C5orf42 by demonstrating abnormal primary cilia and diminished response to a SHH agonist in fibroblasts of C5orf42-mutated patients, as well as axonal pathfinding errors in C5orf42-silenced chicken embryos similar to those observed after perturbation of Shh signaling. Our findings, therefore, suggest that beside the neurodevelopmental features, macrocephaly and facial widening are likely more general signs of disturbed SHH signaling. Nevertheless, long-term follow-up revealed that C5orf42-mutated patients showed catch-up development and fainting of facial features contrary to KIF7-mutated patients.
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Schmitz M, Nelemans BKA, Smit TH. A Submerged Filter Paper Sandwich for Long-term Ex Ovo Time-lapse Imaging of Early Chick Embryos. J Vis Exp 2016. [PMID: 28060338 PMCID: PMC5226633 DOI: 10.3791/54636] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Due to its availability, low cost, flat geometry, and transparency, the ex ovo chick embryo has become a major vertebrate animal model for the study of morphogenetic events, such as gastrulation2, neurulation3-5, somitogenesis6, heart bending7,8, and brain formation9-13, during early embryogenesis. Key to understanding morphogenetic processes is to follow them dynamically by time-lapse imaging. The acquisition of time-lapse movies of chick embryogenesis ex ovo has been limited either to short time windows or to the need for an incubator to control temperature and humidity around the embryo14. Here, we present a new technique to culture chick embryos ex ovo for high-resolution time-lapse imaging using transmitted light microscopy. The submerged filter paper sandwich is a variant of the well-established filter paper carrier technique (EC-culture)1 and allows for the culturing of chick embryos without the need for a climate chamber. The embryo is sandwiched between two identical filter paper carriers and is kept fully submerged in a simple, temperature-controlled medium covered by a layer of light mineral oil. Starting from the primitive streak stage (Hamburger-Hamilton stage 5, HH5)15 up to at least the 28-somite stage (HH16)15, embryos can be cultured with either their ventral or dorsal side up. This allows the acquisition of time-lapse movies covering about 30 hr of embryonic development. Representative time-lapse frames and movies are shown. Embryos are compared morphologically to an embryo cultured in the standard EC-culture. The submerged filter paper sandwich provides a stable environment to study early dorsal and ventral morphogenetic processes. It also allows for live fluorescence imaging and micromanipulations, such as microsurgery, bead implantation, microinjection, gene silencing, and electroporation, and has a strong potential to be combined with immersion objectives for laser-based imaging (including light-sheet microscopy).
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Affiliation(s)
- Manuel Schmitz
- Department of Orthopaedic Surgery, VU University Medical Center Amsterdam, MOVE Research Institute Amsterdam
| | - Ben K A Nelemans
- Department of Orthopaedic Surgery, VU University Medical Center Amsterdam, MOVE Research Institute Amsterdam
| | - Theodoor H Smit
- Department of Anatomy, Embryology & Physiology, Academic Medical Center Amsterdam;
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Long-term primary culture of neurons taken from chick embryo brain: A model to study neural cell biology, synaptogenesis and its dynamic properties. J Neurosci Methods 2016; 263:123-33. [DOI: 10.1016/j.jneumeth.2016.02.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Revised: 01/27/2016] [Accepted: 02/04/2016] [Indexed: 11/20/2022]
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Bjørnstad S, Austdal LPE, Roald B, Glover JC, Paulsen RE. Cracking the Egg: Potential of the Developing Chicken as a Model System for Nonclinical Safety Studies of Pharmaceuticals. J Pharmacol Exp Ther 2015; 355:386-96. [DOI: 10.1124/jpet.115.227025] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2015] [Accepted: 10/01/2015] [Indexed: 12/19/2022] Open
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Avilés EC, Stoeckli ET. Canonical wnt signaling is required for commissural axon guidance. Dev Neurobiol 2015; 76:190-208. [PMID: 26014644 PMCID: PMC4755210 DOI: 10.1002/dneu.22307] [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: 04/30/2015] [Revised: 05/20/2015] [Accepted: 05/20/2015] [Indexed: 12/20/2022]
Abstract
Morphogens have been identified as guidance cues for postcrossing commissural axons in the spinal cord. Shh has a dual effect on postcrossing commissural axons: a direct repellent effect mediated by Hhip as a receptor, and an indirect effect by shaping a Wnt activity gradient. Wnts were shown to be attractants for postcrossing commissural axons in both chicken and mouse embryos. In mouse, the effects of Wnts on axon guidance were concluded to depend on the planar cell polarity (PCP) pathway. Canonical Wnt signaling was excluded based on the absence of axon guidance defects in mice lacking Lrp6 which is an obligatory coreceptor for Fzd in canonical Wnt signaling. In the loss-of-function studies reported here, we confirmed a role for the PCP pathway in postcrossing commissural axon guidance also in the chicken embryo. However, taking advantage of the precise temporal control of gene silencing provided by in ovo RNAi, we demonstrate that canonical Wnt signaling is also required for proper guidance of postcrossing commissural axons in the developing spinal cord. Thus, axon guidance does not seem to depend on any one of the classical Wnt signaling pathways but rather involve a network of Wnt receptors and downstream components.
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Affiliation(s)
- Evelyn C Avilés
- Institute of Molecular Life Sciences and Neuroscience Center Zurich, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland
| | - Esther T Stoeckli
- Institute of Molecular Life Sciences and Neuroscience Center Zurich, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland
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Zhang J, Deng Y, Ma H, Hou J, Zhou Z. Effect of transient receptor potential vanilloid 6 gene silencing on the expression of calcium transport genes in chicken osteoblasts. Poult Sci 2015; 94:395-401. [DOI: 10.3382/ps/peu071] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Stoeckli ET, Kilinc D, Kunz B, Kunz S, Lee GU, Martines E, Rader C, Suter D. Analysis of cell-cell contact mediated by Ig superfamily cell adhesion molecules. CURRENT PROTOCOLS IN CELL BIOLOGY 2013; 61:9.5.1-9.5.85. [PMID: 24510806 DOI: 10.1002/0471143030.cb0905s61] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Cell-cell adhesion is a fundamental requirement for all multicellular organisms. The calcium-independent cell adhesion molecules of the immunoglobulin superfamily (IgSF-CAMs) represent a major subgroup. They consist of immunoglobulin folds alone or in combination with other protein modules, often fibronectin type-III folds. More than 100 IgSF-CAMs have been identified in vertebrates and invertebrates. Most of the IgSF-CAMs are cell surface molecules that are membrane-anchored either by a single transmembrane segment or by a glycosylphosphatidylinositol (GPI) anchor. Some of the IgSF-CAMs also occur in soluble form, e.g., in the cerebrospinal fluid or in the vitreous fluid of the eye, due to naturally occurring cleavage of the GPI anchor or the membrane-proximal peptide segment. Some IgSF-CAMs, such as NCAM, occur in various forms that are generated by alternative splicing. This unit contains a series of protocols that have been used to study the function of IgSF-CAMs in vitro and in vivo.
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Affiliation(s)
- Esther T Stoeckli
- Institute of Molecular Life Sciences, University of Zurich, Zurich, Switzerland
| | - Devrim Kilinc
- School of Chemistry and Chemical Biology, University College Dublin, Belfield, Dublin, Ireland
| | - Beat Kunz
- Institute of Molecular Life Sciences, University of Zurich, Zurich, Switzerland
| | - Stefan Kunz
- Institute of Microbiology, University Hospital Center and University of Lausanne, Lausanne, Switzerland
| | - Gil U Lee
- School of Chemistry and Chemical Biology, University College Dublin, Belfield, Dublin, Ireland
| | - Elena Martines
- Nanomedicine Centre, School of Chemistry and Chemical Biology, University College Dublin, Dublin, Ireland
| | - Christoph Rader
- Department of Cancer Biology, Scripps Florida, Jupiter, Florida
| | - Daniel Suter
- Department of Biological Sciences, Purdue University, West Lafayette, Indiana
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