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Chaturvedi V, Murray MJ. Netrins: Evolutionarily Conserved Regulators of Epithelial Fusion and Closure in Development and Wound Healing. Cells Tissues Organs 2021; 211:193-211. [PMID: 33691313 DOI: 10.1159/000513880] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Accepted: 12/18/2020] [Indexed: 11/19/2022] Open
Abstract
Epithelial remodelling plays a crucial role during development. The ability of epithelial sheets to temporarily lose their integrity as they fuse with other epithelial sheets underpins events such as the closure of the neural tube and palate. During fusion, epithelial cells undergo some degree of epithelial-mesenchymal transition (EMT), whereby cells from opposing sheets dissolve existing cell-cell junctions, degrade the basement membrane, extend motile processes to contact each other, and then re-establish cell-cell junctions as they fuse. Similar events occur when an epithelium is wounded. Cells at the edge of the wound undergo a partial EMT and migrate towards each other to close the gap. In this review, we highlight the emerging role of Netrins in these processes, and provide insights into the possible signalling pathways involved. Netrins are secreted, laminin-like proteins that are evolutionarily conserved throughout the animal kingdom. Although best known as axonal chemotropic guidance molecules, Netrins also regulate epithelial cells. For example, Netrins regulate branching morphogenesis of the lung and mammary gland, and promote EMT during Drosophila wing eversion. Netrins also control epithelial fusion during optic fissure closure and inner ear formation, and are strongly implicated in neural tube closure and secondary palate closure. Netrins are also upregulated in response to organ damage and epithelial wounding, and can protect against ischemia-reperfusion injury and speed wound healing in cornea and skin. Since Netrins also have immunomodulatory properties, and can promote angiogenesis and re-innervation, they hold great promise as potential factors in future wound healing therapies.
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Affiliation(s)
- Vishal Chaturvedi
- School of BioSciences, University of Melbourne, Melbourne, Victoria, Australia
| | - Michael J Murray
- School of BioSciences, University of Melbourne, Melbourne, Victoria, Australia,
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Ephrin-A5 potentiates netrin-1 axon guidance by enhancing Neogenin availability. Sci Rep 2019; 9:12009. [PMID: 31427645 PMCID: PMC6700147 DOI: 10.1038/s41598-019-48519-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Accepted: 08/07/2019] [Indexed: 01/22/2023] Open
Abstract
Axonal growth cones are guided by molecular cues in the extracellular environment. The mechanisms of combinatorial integration of guidance signals at the growth cone cell membrane are still being unravelled. Limb-innervating axons of vertebrate spinal lateral motor column (LMC) neurons are attracted to netrin-1 via its receptor, Neogenin, and are repelled from ephrin-A5 through its receptor EphA4. The presence of both cues elicits synergistic guidance of LMC axons, but the mechanism of this effect remains unknown. Using fluorescence immunohistochemistry, we show that ephrin-A5 increases LMC growth cone Neogenin protein levels and netrin-1 binding. This effect is enhanced by overexpressing EphA4 and is inhibited by blocking ephrin-A5-EphA4 binding. These effects have a functional consequence on LMC growth cone responses since bath addition of ephrin-A5 increases the responsiveness of LMC axons to netrin-1. Surprisingly, the overexpression of EphA4 lacking its cytoplasmic tail, also enhances Neogenin levels at the growth cone and potentiates LMC axon preference for growth on netrin-1. Since netrins and ephrins participate in a wide variety of biological processes, the enhancement of netrin-1 signalling by ephrins may have broad implications.
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O’Leary CJ, Nourse CC, Lee NK, White A, Langford M, Sempert K, Cole SJ, Cooper HM. Neogenin Recruitment of the WAVE Regulatory Complex to Ependymal and Radial Progenitor Adherens Junctions Prevents Hydrocephalus. Cell Rep 2017; 20:370-383. [DOI: 10.1016/j.celrep.2017.06.051] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Revised: 05/11/2017] [Accepted: 06/20/2017] [Indexed: 12/11/2022] Open
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Siebold C, Yamashita T, Monnier PP, Mueller BK, Pasterkamp RJ. RGMs: Structural Insights, Molecular Regulation, and Downstream Signaling. Trends Cell Biol 2017; 27:365-378. [PMID: 28007423 PMCID: PMC5404723 DOI: 10.1016/j.tcb.2016.11.009] [Citation(s) in RCA: 76] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2016] [Revised: 11/27/2016] [Accepted: 11/28/2016] [Indexed: 12/20/2022]
Abstract
Although originally discovered as neuronal growth cone-collapsing factors, repulsive guidance molecules (RGMs) are now known as key players in many fundamental processes, such as cell migration, differentiation, iron homeostasis, and apoptosis, during the development and homeostasis of many tissues and organs, including the nervous, skeletal, and immune systems. Furthermore, three RGMs (RGMa, RGMb/DRAGON, and RGMc/hemojuvelin) have been linked to the pathogenesis of various disorders ranging from multiple sclerosis (MS) to cancer and juvenile hemochromatosis (JHH). While the molecular details of these (patho)biological effects and signaling modes have long remained unknown, recent studies unveil several exciting and novel aspects of RGM processing, ligand-receptor interactions, and downstream signaling. In this review, we highlight recent advances in the mechanisms-of-action and function of RGM proteins.
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Affiliation(s)
- Christian Siebold
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK
| | - Toshihide Yamashita
- Department of Molecular Neuroscience, Graduate School of Medicine, Osaka University, 2-2, Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Philippe P Monnier
- Krembil Research Institute, 60 Leonard Street, M5T 2S8, Toronto, ONT, Canada
| | - Bernhard K Mueller
- Neuroscience Discovery Research, Abbvie, Knollstrasse 50, 67061 Ludwigshafen, Germany
| | - R Jeroen Pasterkamp
- Department of Translational Neuroscience, Brain Center Rudolf Magnus, University Medical Center, Universiteitsweg 100, 3584 CG, Utrecht, The Netherlands.
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Lee NK, Fok KW, White A, Wilson NH, O'Leary CJ, Cox HL, Michael M, Yap AS, Cooper HM. Neogenin recruitment of the WAVE regulatory complex maintains adherens junction stability and tension. Nat Commun 2016; 7:11082. [PMID: 27029596 PMCID: PMC4821876 DOI: 10.1038/ncomms11082] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2016] [Accepted: 02/19/2016] [Indexed: 02/06/2023] Open
Abstract
To maintain tissue integrity during epithelial morphogenesis, adherens junctions (AJs) must resist the mechanical stresses exerted by dynamic tissue movements. Junctional stability is dependent on actomyosin contractility within the actin ring. Here we describe a novel function for the axon guidance receptor, Neogenin, as a key component of the actin nucleation machinery governing junctional stability. Loss of Neogenin perturbs AJs and attenuates junctional tension. Neogenin promotes actin nucleation at AJs by recruiting the Wave regulatory complex (WRC) and Arp2/3. A direct interaction between the Neogenin WIRS domain and the WRC is crucial for the spatially restricted recruitment of the WRC to the junction. Thus, we provide the first example of a functional WIRS–WRC interaction in epithelia. We further show that Neogenin regulates cadherin recycling at the AJ. In summary, we identify Neogenin as a pivotal component of the AJ, where it influences both cadherin dynamics and junctional tension. The stability of epithelial adherens junctions depends on tension generated by actomyosin contractility. Here Lee et al. describe a novel role for the axon guidance receptor Neogenin in maintaining junctional stability by recruiting actin nucleation machinery to adherens junctions.
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Affiliation(s)
- Natalie K Lee
- Queensland Brain Institute, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Ka Wai Fok
- Queensland Brain Institute, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Amanda White
- Queensland Brain Institute, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Nicole H Wilson
- Queensland Brain Institute, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Conor J O'Leary
- Queensland Brain Institute, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Hayley L Cox
- Queensland Brain Institute, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Magdalene Michael
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Alpha S Yap
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Helen M Cooper
- Queensland Brain Institute, The University of Queensland, Brisbane, Queensland 4072, Australia
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O'Leary CJ, Bradford D, Chen M, White A, Blackmore DG, Cooper HM. The Netrin/RGM Receptor, Neogenin, Controls Adult Neurogenesis by Promoting Neuroblast Migration and Cell Cycle Exit. Stem Cells 2015; 33:503-14. [DOI: 10.1002/stem.1861] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2014] [Revised: 07/31/2014] [Accepted: 09/06/2014] [Indexed: 01/16/2023]
Affiliation(s)
- Conor J. O'Leary
- The University of Queensland, Queensland Brain Institute; Brisbane Queensland Australia
| | - DanaKai Bradford
- The University of Queensland, Queensland Brain Institute; Brisbane Queensland Australia
| | - Min Chen
- The University of Queensland, Queensland Brain Institute; Brisbane Queensland Australia
| | - Amanda White
- The University of Queensland, Queensland Brain Institute; Brisbane Queensland Australia
| | - Daniel G. Blackmore
- The University of Queensland, Queensland Brain Institute; Brisbane Queensland Australia
| | - Helen M. Cooper
- The University of Queensland, Queensland Brain Institute; Brisbane Queensland Australia
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O'Leary C, Cole SJ, Langford M, Hewage J, White A, Cooper HM. RGMa regulates cortical interneuron migration and differentiation. PLoS One 2013; 8:e81711. [PMID: 24312340 PMCID: PMC3842424 DOI: 10.1371/journal.pone.0081711] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2013] [Accepted: 10/23/2013] [Indexed: 11/24/2022] Open
Abstract
The etiology of neuropsychiatric disorders, including schizophrenia and autism, has been linked to a failure to establish the intricate neural network comprising excitatory pyramidal and inhibitory interneurons during neocortex development. A large proportion of cortical inhibitory interneurons originate in the medial ganglionic eminence (MGE) of the ventral telencephalon and then migrate through the ventral subventricular zone, across the corticostriatal junction, into the embryonic cortex. Successful navigation of newborn interneurons through the complex environment of the ventral telencephalon is governed by spatiotemporally restricted deployment of both chemorepulsive and chemoattractive guidance cues which work in concert to create a migratory corridor. Despite the expanding list of interneuron guidance cues, cues responsible for preventing interneurons from re-entering the ventricular zone of the ganglionic eminences have not been well characterized. Here we provide evidence that the chemorepulsive axon guidance cue, RGMa (Repulsive Guidance Molecule a), may fulfill this function. The ventricular zone restricted expression of RGMa in the ganglionic eminences and the presence of its receptor, Neogenin, in the ventricular zone and on newborn and maturing MGE-derived interneurons implicates RGMa-Neogenin interactions in interneuron differentiation and migration. Using an in vitro approach, we show that RGMa promotes interneuron differentiation by potentiating neurite outgrowth. In addition, using in vitro explant and migration assays, we provide evidence that RGMa is a repulsive guidance cue for newborn interneurons migrating out of the ganglionic eminence ventricular zone. Intriguingly, the alternative Neogenin ligand, Netrin-1, had no effect on migration. However, we observed complete abrogation of RGMa-induced chemorepulsion when newborn interneurons were simultaneously exposed to RGMa and Netrin-1 gradients, suggesting a novel mechanism for the tight regulation of RGMa-guided interneuron migration. We propose that during peak neurogenesis, repulsive RGMa-Neogenin interactions drive interneurons into the migratory corridor and prevent re-entry into the ventricular zone of the ganglionic eminences.
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Affiliation(s)
- Conor O'Leary
- The University of Queensland, Queensland Brain Institute, Brisbane, Queensland, Australia
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