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Baeriswyl T, Schaettin M, Leoni S, Dumoulin A, Stoeckli ET. Endoglycan Regulates Purkinje Cell Migration by Balancing Cell-Cell Adhesion. Front Neurosci 2022; 16:894962. [PMID: 35794952 PMCID: PMC9251411 DOI: 10.3389/fnins.2022.894962] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2022] [Accepted: 05/20/2022] [Indexed: 11/16/2022] Open
Abstract
The importance of cell adhesion molecules for the development of the nervous system has been recognized many decades ago. Functional in vitro and in vivo studies demonstrated a role of cell adhesion molecules in cell migration, axon growth and guidance, as well as synaptogenesis. Clearly, cell adhesion molecules have to be more than static glue making cells stick together. During axon guidance, cell adhesion molecules have been shown to act as pathway selectors but also as a means to prevent axons going astray by bundling or fasciculating axons. We identified Endoglycan as a negative regulator of cell-cell adhesion during commissural axon guidance across the midline. The presence of Endoglycan allowed commissural growth cones to smoothly navigate the floor-plate area. In the absence of Endoglycan, axons failed to exit the floor plate and turn rostrally. These observations are in line with the idea of Endoglycan acting as a lubricant, as its presence was important, but it did not matter whether Endoglycan was provided by the growth cone or the floor-plate cells. Here, we expand on these observations by demonstrating a role of Endoglycan during cell migration. In the developing cerebellum, Endoglycan was expressed by Purkinje cells during their migration from the ventricular zone to the periphery. In the absence of Endoglycan, Purkinje cells failed to migrate and, as a consequence, cerebellar morphology was strongly affected. Cerebellar folds failed to form and grow, consistent with earlier observations on a role of Purkinje cells as Shh deliverers to trigger granule cell proliferation.
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2
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Yusifov E, Dumoulin A, Stoeckli ET. Investigating Primary Cilia during Peripheral Nervous System Formation. Int J Mol Sci 2021; 22:3176. [PMID: 33804711 PMCID: PMC8003989 DOI: 10.3390/ijms22063176] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Revised: 03/16/2021] [Accepted: 03/16/2021] [Indexed: 12/22/2022] Open
Abstract
The primary cilium plays a pivotal role during the embryonic development of vertebrates. It acts as a somatic signaling hub for specific pathways, such as Sonic Hedgehog signaling. In humans, mutations in genes that cause dysregulation of ciliogenesis or ciliary function lead to severe developmental disorders called ciliopathies. Beyond its role in early morphogenesis, growing evidence points towards an essential function of the primary cilium in neural circuit formation in the central nervous system. However, very little is known about a potential role in the formation of the peripheral nervous system. Here, we investigate the presence of the primary cilium in neural crest cells and their derivatives in the trunk of developing chicken embryos in vivo. We found that neural crest cells, sensory neurons, and boundary cap cells all bear a primary cilium during key stages of early peripheral nervous system formation. Moreover, we describe differences in the ciliation of neuronal cultures of different populations from the peripheral and central nervous systems. Our results offer a framework for further in vivo and in vitro investigations on specific roles that the primary cilium might play during peripheral nervous system formation.
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Affiliation(s)
| | | | - Esther T. Stoeckli
- Department of Molecular Life Sciences and Neuroscience Center Zurich, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland; (E.Y.); (A.D.)
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3
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Dumoulin A, Zuñiga NR, Stoeckli ET. Axon guidance at the spinal cord midline-A live imaging perspective. J Comp Neurol 2021; 529:2517-2538. [PMID: 33438755 PMCID: PMC8248161 DOI: 10.1002/cne.25107] [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: 09/14/2020] [Revised: 12/10/2020] [Accepted: 01/08/2021] [Indexed: 12/19/2022]
Abstract
During neural circuit formation, axons navigate several choice points to reach their final target. At each one of these intermediate targets, growth cones need to switch responsiveness from attraction to repulsion in order to move on. Molecular mechanisms that allow for the precise timing of surface expression of a new set of receptors that support the switch in responsiveness are difficult to study in vivo. Mostly, mechanisms are inferred from the observation of snapshots of many different growth cones analyzed in different preparations of tissue harvested at distinct time points. However, to really understand the behavior of growth cones at choice points, a single growth cone should be followed arriving at and leaving the intermediate target. Existing ex vivo preparations, like cultures of an “open‐book” preparation of the spinal cord have been successfully used to study floor plate entry and exit, but artifacts prevent the analysis of growth cone behavior at the floor plate exit site. Here, we describe a novel spinal cord preparation that allows for live imaging of individual axons during navigation in their intact environment. When comparing growth cone behavior in our ex vivo system with snapshots from in vivo navigation, we do not see any differences. The possibility to observe the dynamics of single growth cones navigating their intermediate target allows for measuring growth speed, changes in morphology, or aberrant behavior, like stalling and wrong turning. Moreover, observation of the intermediate target—the floor plate—revealed its active participation and interaction with commissural axons during midline crossing.
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Affiliation(s)
- Alexandre Dumoulin
- Department of Molecular Life Sciences, University of Zurich, Zurich, Switzerland.,Neuroscience Center Zurich, University of Zurich, Zurich, Switzerland
| | - Nikole R Zuñiga
- Department of Molecular Life Sciences, University of Zurich, Zurich, Switzerland.,Neuroscience Center Zurich, University of Zurich, Zurich, Switzerland
| | - Esther T Stoeckli
- Department of Molecular Life Sciences, University of Zurich, Zurich, Switzerland.,Neuroscience Center Zurich, University of Zurich, Zurich, Switzerland
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4
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Follow Me! A Tale of Avian Heart Development with Comparisons to Mammal Heart Development. J Cardiovasc Dev Dis 2020; 7:jcdd7010008. [PMID: 32156044 PMCID: PMC7151090 DOI: 10.3390/jcdd7010008] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Revised: 02/16/2020] [Accepted: 02/21/2020] [Indexed: 12/19/2022] Open
Abstract
Avian embryos have been used for centuries to study development due to the ease of access. Because the embryos are sheltered inside the eggshell, a small window in the shell is ideal for visualizing the embryos and performing different interventions. The window can then be covered, and the embryo returned to the incubator for the desired amount of time, and observed during further development. Up to about 4 days of chicken development (out of 21 days of incubation), when the egg is opened the embryo is on top of the yolk, and its heart is on top of its body. This allows easy imaging of heart formation and heart development using non-invasive techniques, including regular optical microscopy. After day 4, the embryo starts sinking into the yolk, but still imaging technologies, such as ultrasound, can tomographically image the embryo and its heart in vivo. Importantly, because like the human heart the avian heart develops into a four-chambered heart with valves, heart malformations and pathologies that human babies suffer can be replicated in avian embryos, allowing a unique developmental window into human congenital heart disease. Here, we review avian heart formation and provide comparisons to the mammalian heart.
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5
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Abu-Elmagd M. Use of chick neural tube for optimizing the PSM and epithelial somites electroporation parameters: A detailed protocol. J Biol Methods 2018; 5:e93. [PMID: 31453243 PMCID: PMC6706099 DOI: 10.14440/jbm.2018.253] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Revised: 02/20/2018] [Accepted: 03/29/2018] [Indexed: 11/23/2022] Open
Abstract
Somite myogenesis is one of the crucial early embryonic events that lead to the formation of muscular tissue. A complex of dynamic gene regulatory networks masters this event. To understand and analyze these networks, there remains a genuine need for the use of a reproducible and highly efficient gene transfer technique. In vivo electroporation has proven to be amongst the best approaches in achieving a high level of gene transfer. However, unoptimized electroporation conditions can directly cause varying degrees of cellular damage which may induce abnormal embryonic development as well as changes in the endogenous gene expression. Presegmented mesoderm and epithelial somites are not easy to electroporate. Chick neural tube has served in many functional studies as an ideal experimental model organ which is both robust and easily manipulated. In the current detailed protocol, the neural tube was used as a tool to optimize the electroporation conditions which were subsequently applied in the electroporation of the presegmented mesoderm and epithelial somites. The protocol highlights important notes and hints that enable reproducible results and could be applied in the in vivo electroporation of other chick embryo tissues.
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Affiliation(s)
- Muhammad Abu-Elmagd
- Center of Excellence in Genomic Medicine Research, King Abdulaziz University, Jeddah, Kingdom of Saudi Arabia
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6
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Paces J, Nic M, Novotny T, Svoboda P. Literature review of baseline information to support the risk assessment of RNAi‐based GM plants. ACTA ACUST UNITED AC 2017. [PMCID: PMC7163844 DOI: 10.2903/sp.efsa.2017.en-1246] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Jan Paces
- Institute of Molecular Genetics of the Academy of Sciences of the Czech Republic (IMG)
| | | | | | - Petr Svoboda
- Institute of Molecular Genetics of the Academy of Sciences of the Czech Republic (IMG)
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7
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Himmels P, Paredes I, Adler H, Karakatsani A, Luck R, Marti HH, Ermakova O, Rempel E, Stoeckli ET, Ruiz de Almodóvar C. Motor neurons control blood vessel patterning in the developing spinal cord. Nat Commun 2017; 8:14583. [PMID: 28262664 PMCID: PMC5343469 DOI: 10.1038/ncomms14583] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2016] [Accepted: 01/13/2017] [Indexed: 12/16/2022] Open
Abstract
Formation of a precise vascular network within the central nervous system is of critical importance to assure delivery of oxygen and nutrients and for accurate functionality of neuronal networks. Vascularization of the spinal cord is a highly stereotypical process. However, the guidance cues controlling blood vessel patterning in this organ remain largely unknown. Here we describe a new neuro-vascular communication mechanism that controls vessel guidance in the developing spinal cord. We show that motor neuron columns remain avascular during a developmental time window, despite expressing high levels of the pro-angiogenic vascular endothelial growth factor (VEGF). We describe that motor neurons express the VEGF trapping receptor sFlt1 via a Neuropilin-1-dependent mechanism. Using a VEGF gain-of-function approach in mice and a motor neuron-specific sFlt1 loss-of-function approach in chicken, we show that motor neurons control blood vessel patterning by an autocrine mechanism that titrates motor neuron-derived VEGF via their own expression of sFlt1. The guidance cues regulating blood vessel patterning in the central nervous system remain unclear. Here, the authors show in mice and chicken developing spinal cord that motor neurons control blood vessel patterning by an autocrine mechanism titrating VEGF via the expression of its trapping receptor sFlt1.
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Affiliation(s)
- Patricia Himmels
- Biochemistry Center, Heidelberg University, 69120 Heidelberg, Germany.,Interdisciplinary Center for Neurosciences, Heidelberg University, 69120 Heidelberg, Germany
| | - Isidora Paredes
- Biochemistry Center, Heidelberg University, 69120 Heidelberg, Germany.,Interdisciplinary Center for Neurosciences, Heidelberg University, 69120 Heidelberg, Germany
| | - Heike Adler
- Biochemistry Center, Heidelberg University, 69120 Heidelberg, Germany.,Interdisciplinary Center for Neurosciences, Heidelberg University, 69120 Heidelberg, Germany
| | - Andromachi Karakatsani
- Biochemistry Center, Heidelberg University, 69120 Heidelberg, Germany.,Interdisciplinary Center for Neurosciences, Heidelberg University, 69120 Heidelberg, Germany
| | - Robert Luck
- Biochemistry Center, Heidelberg University, 69120 Heidelberg, Germany.,Interdisciplinary Center for Neurosciences, Heidelberg University, 69120 Heidelberg, Germany
| | - Hugo H Marti
- Institute of Physiology and Pathophysiology, Heidelberg University, 69120 Heidelberg, Germany
| | - Olga Ermakova
- Department of Stem Cell Biology, Centre for Organismal Studies, Heidelberg University, 69120 Heidelberg, Germany
| | - Eugen Rempel
- Department of Stem Cell Biology, Centre for Organismal Studies, Heidelberg University, 69120 Heidelberg, Germany
| | - Esther T Stoeckli
- Institute of Molecular Life Sciences, University of Zurich, 8057 Zurich, Switzerland
| | - Carmen Ruiz de Almodóvar
- Biochemistry Center, Heidelberg University, 69120 Heidelberg, Germany.,Interdisciplinary Center for Neurosciences, Heidelberg University, 69120 Heidelberg, Germany
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8
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Sonic -'Jack-of-All-Trades' in Neural Circuit Formation. J Dev Biol 2017; 5:jdb5010002. [PMID: 29615560 PMCID: PMC5831768 DOI: 10.3390/jdb5010002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Revised: 01/22/2017] [Accepted: 02/01/2017] [Indexed: 12/23/2022] Open
Abstract
As reflected by the term morphogen, molecules such as Shh and Wnts were identified based on their role in early development when they instruct precursor cells to adopt a specific cell fate. Only much later were they implicated in neural circuit formation. Both in vitro and in vivo studies indicated that morphogens direct axons during their navigation through the developing nervous system. Today, the best understood role of Shh and Wnt in axon guidance is their effect on commissural axons in the spinal cord. Shh was shown to affect commissural axons both directly and indirectly via its effect on Wnt signaling. In fact, throughout neural circuit formation there is cross-talk and collaboration of Shh and Wnt signaling. Thus, although the focus of this review is on the role of Shh in neural circuit formation, a separation from Wnt signaling is not possible.
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9
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Hirst CE, Serralbo O, Ayers KL, Roeszler KN, Smith CA. Genetic Manipulation of the Avian Urogenital System Using In Ovo Electroporation. Methods Mol Biol 2017; 1650:177-190. [PMID: 28809021 DOI: 10.1007/978-1-4939-7216-6_11] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
One of the advantages of the avian embryo as an experimental model is its in ovo development and hence accessibility for genetic manipulation. Electroporation has been used extensively in the past to study gene function in chicken and quail embryos . Readily accessible tissues such as the neural tube, somites, and limb bud, in particular, have been targeted. However, more inaccessible tissues, such as the embryonic urogenital system , have proven more challenging to study. Here, we describe the use of in ovo electroporation of TOL2 vectors or RCASBP avian viral vectors for the rapid functional analysis of genes involved in avian sex determination and urogenital development . In the context of the developing urogenital system , these vectors have inherent advantages and disadvantages, which will be considered here. Either vector can both be used for mis-expressing a gene and for targeting endogenous gene knockdown via expression of short hairpin RNAs (shRNAs). Both of these vectors integrate into the genome and are hence spread throughout developing tissues. Going forward, electroporation could be combined with CRISPR/Cas9 technology for targeted genome editing in the avian urogenital system .
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Affiliation(s)
- Claire E Hirst
- Department of Anatomy and Development Biology, Monash University, Clayton, VIC, 3800, USA
| | - Olivier Serralbo
- Australian Regenerative Medicine Institute (ARMI), Monash University, Clayton, VIC, USA
| | - Katie L Ayers
- Murdoch Children's Research Institute, Royal Children's Hospital, The University of Melbourne, Melbourne, VIC, Australia
- Department of Paediatrics, Royal Children's Hospital, The University of Melbourne, Melbourne, VIC, Australia
| | - Kelly N Roeszler
- Murdoch Children's Research Institute, Royal Children's Hospital, The University of Melbourne, Melbourne, VIC, Australia
- Department of Paediatrics, Royal Children's Hospital, The University of Melbourne, Melbourne, VIC, Australia
| | - Craig A Smith
- Department of Anatomy and Development Biology, Monash University, Clayton, VIC, 3800, USA.
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10
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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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11
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Wilson N, Stoeckli E. Open-book Preparations from Chick Embryos and DiI Labeling of Commissural Axons. Bio Protoc 2014. [DOI: 10.21769/bioprotoc.1176] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022] Open
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