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Changes in Myonuclear Number During Postnatal Growth – Implications for AAV Gene Therapy for Muscular Dystrophy

Adult skeletal muscle is a relatively stable tissue, as the multinucleated muscle fibres contain post-mitotic myonuclei. During early postnatal life, muscle growth occurs by the addition of skeletal muscle stem cells (satellite cells) or their progeny to growing muscle fibres. In Duchenne muscular d...

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Autores principales: Morgan, Jennifer, Muntoni, Francesco
Formato: Online Artículo Texto
Lenguaje:English
Publicado: IOS Press 2021
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8673494/
https://www.ncbi.nlm.nih.gov/pubmed/34334413
http://dx.doi.org/10.3233/JND-210683
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author Morgan, Jennifer
Muntoni, Francesco
author_facet Morgan, Jennifer
Muntoni, Francesco
author_sort Morgan, Jennifer
collection PubMed
description Adult skeletal muscle is a relatively stable tissue, as the multinucleated muscle fibres contain post-mitotic myonuclei. During early postnatal life, muscle growth occurs by the addition of skeletal muscle stem cells (satellite cells) or their progeny to growing muscle fibres. In Duchenne muscular dystrophy, which we shall use as an example of muscular dystrophies, the muscle fibres lack dystrophin and undergo necrosis. Satellite-cell mediated regeneration occurs, to repair and replace the necrotic muscle fibres, but as the regenerated muscle fibres still lack dystrophin, they undergo further cycles of degeneration and regeneration. AAV gene therapy is a promising approach for treating Duchenne muscular dystrophy. But for a single dose of, for example, AAV coding for microdystrophin, to be effective, the treated myonuclei must persist, produce sufficient dystrophin and a sufficient number of nuclei must be targeted. This latter point is crucial as AAV vector remains episomal and does not replicate in dividing cells. Here, we describe and compare the growth of skeletal muscle in rodents and in humans and discuss the evidence that myofibre necrosis and regeneration leads to the loss of viral genomes within skeletal muscle. In addition, muscle growth is expected to lead to the dilution of the transduced nuclei especially in case of very early intervention, but it is not clear if growth could result in insufficient dystrophin to prevent muscle fibre breakdown. This should be the focus of future studies.
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spelling pubmed-86734942021-12-29 Changes in Myonuclear Number During Postnatal Growth – Implications for AAV Gene Therapy for Muscular Dystrophy Morgan, Jennifer Muntoni, Francesco J Neuromuscul Dis Review Adult skeletal muscle is a relatively stable tissue, as the multinucleated muscle fibres contain post-mitotic myonuclei. During early postnatal life, muscle growth occurs by the addition of skeletal muscle stem cells (satellite cells) or their progeny to growing muscle fibres. In Duchenne muscular dystrophy, which we shall use as an example of muscular dystrophies, the muscle fibres lack dystrophin and undergo necrosis. Satellite-cell mediated regeneration occurs, to repair and replace the necrotic muscle fibres, but as the regenerated muscle fibres still lack dystrophin, they undergo further cycles of degeneration and regeneration. AAV gene therapy is a promising approach for treating Duchenne muscular dystrophy. But for a single dose of, for example, AAV coding for microdystrophin, to be effective, the treated myonuclei must persist, produce sufficient dystrophin and a sufficient number of nuclei must be targeted. This latter point is crucial as AAV vector remains episomal and does not replicate in dividing cells. Here, we describe and compare the growth of skeletal muscle in rodents and in humans and discuss the evidence that myofibre necrosis and regeneration leads to the loss of viral genomes within skeletal muscle. In addition, muscle growth is expected to lead to the dilution of the transduced nuclei especially in case of very early intervention, but it is not clear if growth could result in insufficient dystrophin to prevent muscle fibre breakdown. This should be the focus of future studies. IOS Press 2021-11-30 /pmc/articles/PMC8673494/ /pubmed/34334413 http://dx.doi.org/10.3233/JND-210683 Text en © 2021 – The authors. Published by IOS Press https://creativecommons.org/licenses/by-nc/4.0/This is an open access article distributed under the terms of the Creative Commons Attribution Non-Commercial (CC BY-NC 4.0) License (https://creativecommons.org/licenses/by-nc/4.0/) , which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
spellingShingle Review
Morgan, Jennifer
Muntoni, Francesco
Changes in Myonuclear Number During Postnatal Growth – Implications for AAV Gene Therapy for Muscular Dystrophy
title Changes in Myonuclear Number During Postnatal Growth – Implications for AAV Gene Therapy for Muscular Dystrophy
title_full Changes in Myonuclear Number During Postnatal Growth – Implications for AAV Gene Therapy for Muscular Dystrophy
title_fullStr Changes in Myonuclear Number During Postnatal Growth – Implications for AAV Gene Therapy for Muscular Dystrophy
title_full_unstemmed Changes in Myonuclear Number During Postnatal Growth – Implications for AAV Gene Therapy for Muscular Dystrophy
title_short Changes in Myonuclear Number During Postnatal Growth – Implications for AAV Gene Therapy for Muscular Dystrophy
title_sort changes in myonuclear number during postnatal growth – implications for aav gene therapy for muscular dystrophy
topic Review
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8673494/
https://www.ncbi.nlm.nih.gov/pubmed/34334413
http://dx.doi.org/10.3233/JND-210683
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