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Macrophage-specific RhoA knockout delays Wallerian degeneration after peripheral nerve injury in mice

BACKGROUND: Plenty of macrophages are recruited to the injured nerve to play key roles in the immunoreaction and engulf the debris of degenerated axons and myelin during Wallerian degeneration, thus creating a conducive microenvironment for nerve regeneration. Recently, drugs targeting the RhoA path...

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Autores principales: Xu, Jiawei, Wen, Jinkun, Fu, Lanya, Liao, Liqiang, Zou, Ying, Zhang, Jiaqi, Deng, Junyao, Zhang, Haowen, Liu, Jingmin, Wang, Xianghai, Zuo, Daming, Guo, Jiasong
Formato: Online Artículo Texto
Lenguaje:English
Publicado: BioMed Central 2021
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8520251/
https://www.ncbi.nlm.nih.gov/pubmed/34654444
http://dx.doi.org/10.1186/s12974-021-02292-y
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author Xu, Jiawei
Wen, Jinkun
Fu, Lanya
Liao, Liqiang
Zou, Ying
Zhang, Jiaqi
Deng, Junyao
Zhang, Haowen
Liu, Jingmin
Wang, Xianghai
Zuo, Daming
Guo, Jiasong
author_facet Xu, Jiawei
Wen, Jinkun
Fu, Lanya
Liao, Liqiang
Zou, Ying
Zhang, Jiaqi
Deng, Junyao
Zhang, Haowen
Liu, Jingmin
Wang, Xianghai
Zuo, Daming
Guo, Jiasong
author_sort Xu, Jiawei
collection PubMed
description BACKGROUND: Plenty of macrophages are recruited to the injured nerve to play key roles in the immunoreaction and engulf the debris of degenerated axons and myelin during Wallerian degeneration, thus creating a conducive microenvironment for nerve regeneration. Recently, drugs targeting the RhoA pathway have been widely used to promote peripheral axonal regeneration. However, the role of RhoA in macrophage during Wallerian degeneration and nerve regeneration after peripheral nerve injury is still unknown. Herein, we come up with the hypothesis that RhoA might influence Wallerian degeneration and nerve regeneration by affecting the migration and phagocytosis of macrophages after peripheral nerve injury. METHODS: Immunohistochemistry, Western blotting, H&E staining, and electrophysiology were performed to access the Wallerian degeneration and axonal regeneration after sciatic nerve transection and crush injury in the Lyz(Cre+/−); RhoA(flox/flox) (cKO) mice or Lyz2(Cre+/−) (Cre) mice, regardless of sex. Macrophages’ migration and phagocytosis were detected in the injured nerves and the cultured macrophages. Moreover, the expression and potential roles of ROCK and MLCK were also evaluated in the cultured macrophages. RESULTS: 1. RhoA was specifically knocked out in macrophages of the cKO mice; 2. The segmentation of axons and myelin, the axonal regeneration, and nerve conduction in the injured nerve were significantly impeded while the myoatrophy was more severe in the cKO mice compared with those in Cre mice; 3. RhoA knockout attenuated the migration and phagocytosis of macrophages in vivo and in vitro; 4. ROCK and MLCK were downregulated in the cKO macrophages while inhibition of ROCK and MLCK could weaken the migration and phagocytosis of macrophages. CONCLUSIONS: Our findings suggest that RhoA depletion in macrophages exerts a detrimental effect on Wallerian degeneration and nerve regeneration, which is most likely due to the impaired migration and phagocytosis of macrophages resulted from disrupted RhoA/ROCK/MLCK pathway. Since previous research has proved RhoA inhibition in neurons was favoring for axonal regeneration, the present study reminds us of that the cellular specificity of RhoA-targeted drugs is needed to be considered in the future application for treating peripheral nerve injury.
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spelling pubmed-85202512021-10-20 Macrophage-specific RhoA knockout delays Wallerian degeneration after peripheral nerve injury in mice Xu, Jiawei Wen, Jinkun Fu, Lanya Liao, Liqiang Zou, Ying Zhang, Jiaqi Deng, Junyao Zhang, Haowen Liu, Jingmin Wang, Xianghai Zuo, Daming Guo, Jiasong J Neuroinflammation Research BACKGROUND: Plenty of macrophages are recruited to the injured nerve to play key roles in the immunoreaction and engulf the debris of degenerated axons and myelin during Wallerian degeneration, thus creating a conducive microenvironment for nerve regeneration. Recently, drugs targeting the RhoA pathway have been widely used to promote peripheral axonal regeneration. However, the role of RhoA in macrophage during Wallerian degeneration and nerve regeneration after peripheral nerve injury is still unknown. Herein, we come up with the hypothesis that RhoA might influence Wallerian degeneration and nerve regeneration by affecting the migration and phagocytosis of macrophages after peripheral nerve injury. METHODS: Immunohistochemistry, Western blotting, H&E staining, and electrophysiology were performed to access the Wallerian degeneration and axonal regeneration after sciatic nerve transection and crush injury in the Lyz(Cre+/−); RhoA(flox/flox) (cKO) mice or Lyz2(Cre+/−) (Cre) mice, regardless of sex. Macrophages’ migration and phagocytosis were detected in the injured nerves and the cultured macrophages. Moreover, the expression and potential roles of ROCK and MLCK were also evaluated in the cultured macrophages. RESULTS: 1. RhoA was specifically knocked out in macrophages of the cKO mice; 2. The segmentation of axons and myelin, the axonal regeneration, and nerve conduction in the injured nerve were significantly impeded while the myoatrophy was more severe in the cKO mice compared with those in Cre mice; 3. RhoA knockout attenuated the migration and phagocytosis of macrophages in vivo and in vitro; 4. ROCK and MLCK were downregulated in the cKO macrophages while inhibition of ROCK and MLCK could weaken the migration and phagocytosis of macrophages. CONCLUSIONS: Our findings suggest that RhoA depletion in macrophages exerts a detrimental effect on Wallerian degeneration and nerve regeneration, which is most likely due to the impaired migration and phagocytosis of macrophages resulted from disrupted RhoA/ROCK/MLCK pathway. Since previous research has proved RhoA inhibition in neurons was favoring for axonal regeneration, the present study reminds us of that the cellular specificity of RhoA-targeted drugs is needed to be considered in the future application for treating peripheral nerve injury. BioMed Central 2021-10-15 /pmc/articles/PMC8520251/ /pubmed/34654444 http://dx.doi.org/10.1186/s12974-021-02292-y Text en © The Author(s) 2021 https://creativecommons.org/licenses/by/4.0/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/ (https://creativecommons.org/licenses/by/4.0/) . The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/ (https://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
Xu, Jiawei
Wen, Jinkun
Fu, Lanya
Liao, Liqiang
Zou, Ying
Zhang, Jiaqi
Deng, Junyao
Zhang, Haowen
Liu, Jingmin
Wang, Xianghai
Zuo, Daming
Guo, Jiasong
Macrophage-specific RhoA knockout delays Wallerian degeneration after peripheral nerve injury in mice
title Macrophage-specific RhoA knockout delays Wallerian degeneration after peripheral nerve injury in mice
title_full Macrophage-specific RhoA knockout delays Wallerian degeneration after peripheral nerve injury in mice
title_fullStr Macrophage-specific RhoA knockout delays Wallerian degeneration after peripheral nerve injury in mice
title_full_unstemmed Macrophage-specific RhoA knockout delays Wallerian degeneration after peripheral nerve injury in mice
title_short Macrophage-specific RhoA knockout delays Wallerian degeneration after peripheral nerve injury in mice
title_sort macrophage-specific rhoa knockout delays wallerian degeneration after peripheral nerve injury in mice
topic Research
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8520251/
https://www.ncbi.nlm.nih.gov/pubmed/34654444
http://dx.doi.org/10.1186/s12974-021-02292-y
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