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Early myelination involves the dynamic and repetitive ensheathment of axons which resolves through a low and consistent stabilization rate

Oligodendrocytes in the central nervous system exhibit significant variability in the number of myelin sheaths that are supported by each cell, ranging from 1 to 50 (1-8). Myelin production during development is dynamic and involves both sheath formation and loss (3, 9-13). However, how these parame...

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Autores principales: Almeida, Adam R, Macklin, Wendy B
Formato: Online Artículo Texto
Lenguaje:English
Publicado: eLife Sciences Publications, Ltd 2023
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10198724/
https://www.ncbi.nlm.nih.gov/pubmed/37078701
http://dx.doi.org/10.7554/eLife.82111
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author Almeida, Adam R
Macklin, Wendy B
author_facet Almeida, Adam R
Macklin, Wendy B
author_sort Almeida, Adam R
collection PubMed
description Oligodendrocytes in the central nervous system exhibit significant variability in the number of myelin sheaths that are supported by each cell, ranging from 1 to 50 (1-8). Myelin production during development is dynamic and involves both sheath formation and loss (3, 9-13). However, how these parameters are balanced to generate this heterogeneity in sheath number has not been thoroughly investigated. To explore this question, we combined extensive time-lapse and longitudinal imaging of oligodendrocytes in the developing zebrafish spinal cord to quantify sheath initiation and loss. Surprisingly, we found that oligodendrocytes repetitively ensheathed the same axons multiple times before any stable sheaths were formed. Importantly, this repetitive ensheathment was independent of neuronal activity. At the level of individual oligodendrocytes, each cell initiated a highly variable number of total ensheathments. However, ~80–90% of these ensheathments always disappeared, an unexpectedly high, but consistent rate of loss. The dynamics of this process indicated rapid membrane turnover as ensheathments were formed and lost repetitively on each axon. To better understand how these sheath initiation dynamics contribute to sheath accumulation and stabilization, we disrupted membrane recycling by expressing a dominant-negative mutant form of Rab5. Oligodendrocytes over-expressing this mutant did not show a change in early sheath initiation dynamics but did lose a higher percentage of ensheathments in the later stabilization phase. Overall, oligodendrocyte sheath number is heterogeneous because each cell repetitively initiates a variable number of total ensheathments that are resolved through a consistent stabilization rate.
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spelling pubmed-101987242023-05-20 Early myelination involves the dynamic and repetitive ensheathment of axons which resolves through a low and consistent stabilization rate Almeida, Adam R Macklin, Wendy B eLife Neuroscience Oligodendrocytes in the central nervous system exhibit significant variability in the number of myelin sheaths that are supported by each cell, ranging from 1 to 50 (1-8). Myelin production during development is dynamic and involves both sheath formation and loss (3, 9-13). However, how these parameters are balanced to generate this heterogeneity in sheath number has not been thoroughly investigated. To explore this question, we combined extensive time-lapse and longitudinal imaging of oligodendrocytes in the developing zebrafish spinal cord to quantify sheath initiation and loss. Surprisingly, we found that oligodendrocytes repetitively ensheathed the same axons multiple times before any stable sheaths were formed. Importantly, this repetitive ensheathment was independent of neuronal activity. At the level of individual oligodendrocytes, each cell initiated a highly variable number of total ensheathments. However, ~80–90% of these ensheathments always disappeared, an unexpectedly high, but consistent rate of loss. The dynamics of this process indicated rapid membrane turnover as ensheathments were formed and lost repetitively on each axon. To better understand how these sheath initiation dynamics contribute to sheath accumulation and stabilization, we disrupted membrane recycling by expressing a dominant-negative mutant form of Rab5. Oligodendrocytes over-expressing this mutant did not show a change in early sheath initiation dynamics but did lose a higher percentage of ensheathments in the later stabilization phase. Overall, oligodendrocyte sheath number is heterogeneous because each cell repetitively initiates a variable number of total ensheathments that are resolved through a consistent stabilization rate. eLife Sciences Publications, Ltd 2023-04-20 /pmc/articles/PMC10198724/ /pubmed/37078701 http://dx.doi.org/10.7554/eLife.82111 Text en © 2023, Almeida and Macklin https://creativecommons.org/licenses/by/4.0/This article is distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/) , which permits unrestricted use and redistribution provided that the original author and source are credited.
spellingShingle Neuroscience
Almeida, Adam R
Macklin, Wendy B
Early myelination involves the dynamic and repetitive ensheathment of axons which resolves through a low and consistent stabilization rate
title Early myelination involves the dynamic and repetitive ensheathment of axons which resolves through a low and consistent stabilization rate
title_full Early myelination involves the dynamic and repetitive ensheathment of axons which resolves through a low and consistent stabilization rate
title_fullStr Early myelination involves the dynamic and repetitive ensheathment of axons which resolves through a low and consistent stabilization rate
title_full_unstemmed Early myelination involves the dynamic and repetitive ensheathment of axons which resolves through a low and consistent stabilization rate
title_short Early myelination involves the dynamic and repetitive ensheathment of axons which resolves through a low and consistent stabilization rate
title_sort early myelination involves the dynamic and repetitive ensheathment of axons which resolves through a low and consistent stabilization rate
topic Neuroscience
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10198724/
https://www.ncbi.nlm.nih.gov/pubmed/37078701
http://dx.doi.org/10.7554/eLife.82111
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