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Skeletal muscle healing by M1-like macrophages produced by transient expression of exogenous GM-CSF
BACKGROUND: After traumatic skeletal muscle injury, muscle healing is often incomplete and produces extensive fibrosis. The sequence of M1 and M2 macrophage accumulation and the duration of each subtype in the injured area may help to direct the relative extent of fibrogenesis and myogenesis during...
Autores principales: | , , , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
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BioMed Central
2020
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7648431/ https://www.ncbi.nlm.nih.gov/pubmed/33158459 http://dx.doi.org/10.1186/s13287-020-01992-1 |
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author | Martins, Leonardo Gallo, Camila Congentino Honda, Tâmisa Seeko Bandeira Alves, Patrícia Terra Stilhano, Roberta Sessa Rosa, Daniela Santoro Koh, Timothy Jon Han, Sang Won |
author_facet | Martins, Leonardo Gallo, Camila Congentino Honda, Tâmisa Seeko Bandeira Alves, Patrícia Terra Stilhano, Roberta Sessa Rosa, Daniela Santoro Koh, Timothy Jon Han, Sang Won |
author_sort | Martins, Leonardo |
collection | PubMed |
description | BACKGROUND: After traumatic skeletal muscle injury, muscle healing is often incomplete and produces extensive fibrosis. The sequence of M1 and M2 macrophage accumulation and the duration of each subtype in the injured area may help to direct the relative extent of fibrogenesis and myogenesis during healing. We hypothesized that increasing the number of M1 macrophages early after traumatic muscle injury would produce more cellular and molecular substrates for myogenesis and fewer substrates for fibrosis, leading to better muscle healing. METHODS: To test this hypothesis, we transfected skeletal muscle with a plasmid vector to transiently express GM-CSF shortly after injury to drive the polarization of macrophages towards the M1 subset. C57BL/6 mouse tibialis anterior (TA) muscles were injured by contusion and electroporated with uP-mGM, which is a plasmid vector that transiently expresses GM-CSF. Myogenesis, angiogenesis, and fibrosis were evaluated by histology, immunohistochemistry, and RT-qPCR; subpopulations of macrophages by flow cytometry; and muscle functioning by the maximum running speed on the treadmill and the recovery of muscle mass. RESULTS: Muscle injury increased the number of local M1-like macrophages and decreased the number of M2-like macrophages on day 4, and uP-mGM treatment enhanced this variation. uP-mGM treatment decreased TGF-β1 protein expression on day 4, and the Sirius Red-positive area decreased from 35.93 ± 15.45% (no treatment) to 2.9% ± 6.5% (p < 0.01) on day 30. uP-mGM electroporation also increased Hgf, Hif1α, and Mtor gene expression; arteriole density; and muscle fiber number during regeneration. The improvement in the quality of the muscle tissue after treatment with uP-mGM affected the increase in the TA muscle mass and the maximum running speed on a treadmill. CONCLUSION: Collectively, our data show that increasing the number of M1-like macrophages immediately after traumatic muscle injury promotes muscle recovery with less fibrosis, and this can be achieved by the transient expression of GM-CSF. |
format | Online Article Text |
id | pubmed-7648431 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2020 |
publisher | BioMed Central |
record_format | MEDLINE/PubMed |
spelling | pubmed-76484312020-11-09 Skeletal muscle healing by M1-like macrophages produced by transient expression of exogenous GM-CSF Martins, Leonardo Gallo, Camila Congentino Honda, Tâmisa Seeko Bandeira Alves, Patrícia Terra Stilhano, Roberta Sessa Rosa, Daniela Santoro Koh, Timothy Jon Han, Sang Won Stem Cell Res Ther Research BACKGROUND: After traumatic skeletal muscle injury, muscle healing is often incomplete and produces extensive fibrosis. The sequence of M1 and M2 macrophage accumulation and the duration of each subtype in the injured area may help to direct the relative extent of fibrogenesis and myogenesis during healing. We hypothesized that increasing the number of M1 macrophages early after traumatic muscle injury would produce more cellular and molecular substrates for myogenesis and fewer substrates for fibrosis, leading to better muscle healing. METHODS: To test this hypothesis, we transfected skeletal muscle with a plasmid vector to transiently express GM-CSF shortly after injury to drive the polarization of macrophages towards the M1 subset. C57BL/6 mouse tibialis anterior (TA) muscles were injured by contusion and electroporated with uP-mGM, which is a plasmid vector that transiently expresses GM-CSF. Myogenesis, angiogenesis, and fibrosis were evaluated by histology, immunohistochemistry, and RT-qPCR; subpopulations of macrophages by flow cytometry; and muscle functioning by the maximum running speed on the treadmill and the recovery of muscle mass. RESULTS: Muscle injury increased the number of local M1-like macrophages and decreased the number of M2-like macrophages on day 4, and uP-mGM treatment enhanced this variation. uP-mGM treatment decreased TGF-β1 protein expression on day 4, and the Sirius Red-positive area decreased from 35.93 ± 15.45% (no treatment) to 2.9% ± 6.5% (p < 0.01) on day 30. uP-mGM electroporation also increased Hgf, Hif1α, and Mtor gene expression; arteriole density; and muscle fiber number during regeneration. The improvement in the quality of the muscle tissue after treatment with uP-mGM affected the increase in the TA muscle mass and the maximum running speed on a treadmill. CONCLUSION: Collectively, our data show that increasing the number of M1-like macrophages immediately after traumatic muscle injury promotes muscle recovery with less fibrosis, and this can be achieved by the transient expression of GM-CSF. BioMed Central 2020-11-06 /pmc/articles/PMC7648431/ /pubmed/33158459 http://dx.doi.org/10.1186/s13287-020-01992-1 Text en © The Author(s) 2020 Open AccessThis article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated in a credit line to the data. |
spellingShingle | Research Martins, Leonardo Gallo, Camila Congentino Honda, Tâmisa Seeko Bandeira Alves, Patrícia Terra Stilhano, Roberta Sessa Rosa, Daniela Santoro Koh, Timothy Jon Han, Sang Won Skeletal muscle healing by M1-like macrophages produced by transient expression of exogenous GM-CSF |
title | Skeletal muscle healing by M1-like macrophages produced by transient expression of exogenous GM-CSF |
title_full | Skeletal muscle healing by M1-like macrophages produced by transient expression of exogenous GM-CSF |
title_fullStr | Skeletal muscle healing by M1-like macrophages produced by transient expression of exogenous GM-CSF |
title_full_unstemmed | Skeletal muscle healing by M1-like macrophages produced by transient expression of exogenous GM-CSF |
title_short | Skeletal muscle healing by M1-like macrophages produced by transient expression of exogenous GM-CSF |
title_sort | skeletal muscle healing by m1-like macrophages produced by transient expression of exogenous gm-csf |
topic | Research |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7648431/ https://www.ncbi.nlm.nih.gov/pubmed/33158459 http://dx.doi.org/10.1186/s13287-020-01992-1 |
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