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How scars shape the neural landscape: Key molecular mediators of TGF-β1’s anti-neuritogenic effects

Following injury to the peripheral and central nervous systems, tissue levels of transforming growth factor (TGF)-β1 often increase, which is key for wound healing and scarring. However, active wound regions and scars appear to inhibit process outgrowth by regenerating neurons. We recently showed th...

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Detalles Bibliográficos
Autores principales: Jeon, Kye-Im, Huxlin, Krystel R.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Public Library of Science 2020
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7685464/
https://www.ncbi.nlm.nih.gov/pubmed/33232327
http://dx.doi.org/10.1371/journal.pone.0234950
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author Jeon, Kye-Im
Huxlin, Krystel R.
author_facet Jeon, Kye-Im
Huxlin, Krystel R.
author_sort Jeon, Kye-Im
collection PubMed
description Following injury to the peripheral and central nervous systems, tissue levels of transforming growth factor (TGF)-β1 often increase, which is key for wound healing and scarring. However, active wound regions and scars appear to inhibit process outgrowth by regenerating neurons. We recently showed that corneal wound myofibroblasts block corneal nerve regeneration in vivo, and sensory neurite outgrowth in vitro in a manner that relies critically on TGF-β1. In turn, delayed, abnormal re-innervation contributes to long-term sensory dysfunctions of the ocular surface. Here, we exposed morphologically and biochemically-differentiated sensory neurons from the ND7/23 cell line to TGF-β1 to identify the intracellular signals regulating these anti-neuritogenic effects, contrasting them with those of Semaphorin(Sema)3A, a known inhibitor of neurite outgrowth. Neuronal morphology was quantified using phase-contrast imaging. Western blotting and specific inhibitors were then used to identify key molecular mediators. Differentiated ND7/23 cells expressed neuron-specific markers, including those involved in neurite extension and polarization. TGF-β1 increased phosphorylation of collapsin response mediator protein-2 (CRMP2), a molecule that is key for neurite extension. We now show that both glycogen synthase kinase (GSK)-3β and Smad3 modulate phosphorylation of CRMP2 after treatment with TGF-β1. GSK-3β appeared to exert a particularly strong effect, which could be explained by its ability to phosphorylate not only CRMP2, but also Smad3. In conclusion, TGF-β1’s inhibition of neurite outgrowth in sensory neurons appears to be regulated through a highly-conserved signaling pathway, which involves the GSK-3β/CRMP-2 loop via both canonical and non-canonical mechanisms. It is hoped that by defining the signaling pathways that control neurite outgrowth in wound environments, it will become possible to identify optimal molecular targets to promote re-innervation following injury.
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spelling pubmed-76854642020-12-02 How scars shape the neural landscape: Key molecular mediators of TGF-β1’s anti-neuritogenic effects Jeon, Kye-Im Huxlin, Krystel R. PLoS One Research Article Following injury to the peripheral and central nervous systems, tissue levels of transforming growth factor (TGF)-β1 often increase, which is key for wound healing and scarring. However, active wound regions and scars appear to inhibit process outgrowth by regenerating neurons. We recently showed that corneal wound myofibroblasts block corneal nerve regeneration in vivo, and sensory neurite outgrowth in vitro in a manner that relies critically on TGF-β1. In turn, delayed, abnormal re-innervation contributes to long-term sensory dysfunctions of the ocular surface. Here, we exposed morphologically and biochemically-differentiated sensory neurons from the ND7/23 cell line to TGF-β1 to identify the intracellular signals regulating these anti-neuritogenic effects, contrasting them with those of Semaphorin(Sema)3A, a known inhibitor of neurite outgrowth. Neuronal morphology was quantified using phase-contrast imaging. Western blotting and specific inhibitors were then used to identify key molecular mediators. Differentiated ND7/23 cells expressed neuron-specific markers, including those involved in neurite extension and polarization. TGF-β1 increased phosphorylation of collapsin response mediator protein-2 (CRMP2), a molecule that is key for neurite extension. We now show that both glycogen synthase kinase (GSK)-3β and Smad3 modulate phosphorylation of CRMP2 after treatment with TGF-β1. GSK-3β appeared to exert a particularly strong effect, which could be explained by its ability to phosphorylate not only CRMP2, but also Smad3. In conclusion, TGF-β1’s inhibition of neurite outgrowth in sensory neurons appears to be regulated through a highly-conserved signaling pathway, which involves the GSK-3β/CRMP-2 loop via both canonical and non-canonical mechanisms. It is hoped that by defining the signaling pathways that control neurite outgrowth in wound environments, it will become possible to identify optimal molecular targets to promote re-innervation following injury. Public Library of Science 2020-11-24 /pmc/articles/PMC7685464/ /pubmed/33232327 http://dx.doi.org/10.1371/journal.pone.0234950 Text en © 2020 Jeon, Huxlin http://creativecommons.org/licenses/by/4.0/ This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/) , which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
spellingShingle Research Article
Jeon, Kye-Im
Huxlin, Krystel R.
How scars shape the neural landscape: Key molecular mediators of TGF-β1’s anti-neuritogenic effects
title How scars shape the neural landscape: Key molecular mediators of TGF-β1’s anti-neuritogenic effects
title_full How scars shape the neural landscape: Key molecular mediators of TGF-β1’s anti-neuritogenic effects
title_fullStr How scars shape the neural landscape: Key molecular mediators of TGF-β1’s anti-neuritogenic effects
title_full_unstemmed How scars shape the neural landscape: Key molecular mediators of TGF-β1’s anti-neuritogenic effects
title_short How scars shape the neural landscape: Key molecular mediators of TGF-β1’s anti-neuritogenic effects
title_sort how scars shape the neural landscape: key molecular mediators of tgf-β1’s anti-neuritogenic effects
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7685464/
https://www.ncbi.nlm.nih.gov/pubmed/33232327
http://dx.doi.org/10.1371/journal.pone.0234950
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