Adult skeletal muscle is a plastic tissue that can adapt its size to workload. Here, we show that RhoA within myofibers is needed for overload-induced hypertrophy by controlling satellite cell (SC) fusion to the growing myofibers without affecting protein synthesis. At the molecular level, we demonstrate that RhoA controls in a cell autonomous manner Erk1/2 activation and the expressions of extracellular matrix (ECM) regulators such as and macrophage chemo-attractants such as / Their decreased expression in RhoA mutants is associated with ECM and fibrillar collagen disorganization and lower macrophage infiltration. Moreover, matrix metalloproteinases inhibition and macrophage depletion in controls phenocopied the altered growth of RhoA mutants while having no effect in mutants showing that their action is RhoA-dependent. These findings unravel the implication of RhoA within myofibers, in the building of a permissive microenvironment for muscle hypertrophic growth and for SC accretion through ECM remodeling and inflammatory cell recruitment.
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http://dx.doi.org/10.1016/j.isci.2021.103616 | DOI Listing |
Cells
November 2023
Institut Cochin, Université de Paris, INSERM U1016, CNRS, F-75014 Paris, France.
Satellite cells (SCs) are adult muscle stem cells that are mobilized when muscle homeostasis is perturbed. Here we show that RhoA in SCs is indispensable to have correct muscle regeneration and hypertrophy. In particular, the absence of RhoA in SCs prevents a correct SC fusion both to other RhoA-deleted SCs (regeneration context) and to growing control myofibers (hypertrophy context).
View Article and Find Full Text PDFAm J Physiol Heart Circ Physiol
February 2024
Department of Bioengineering, University of California San Diego, La Jolla, California, United States.
To identify how cardiomyocyte mechanosensitive signaling pathways are regulated by anisotropic stretch, micropatterned mouse neonatal cardiomyocytes were stretched primarily longitudinally or transversely to the myofiber axis. Four hours of static, longitudinal stretch induced differential expression of 557 genes, compared with 30 induced by transverse stretch, measured using RNA-seq. A logic-based ordinary differential equation model of the cardiac myocyte mechanosignaling network, extended to include the transcriptional regulation and expression of 784 genes, correctly predicted measured expression changes due to anisotropic stretch with 69% accuracy.
View Article and Find Full Text PDFJ Cachexia Sarcopenia Muscle
February 2023
Department of Pharmacology, Tianjin Key Laboratory of Inflammatory Biology, Center for Cardiovascular Diseases, Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), The Province and Ministry Co-sponsored Collaborative Innovation Center for Medical Epigenetics, School of Basic Medical Sciences, Tianjin Medical University, Tianjin, China.
Background: Mammalian skeletal muscles consist of two main fibre types: slow-twitch (type I, oxidative) and fast-twitch (type IIa, fast oxidative; type IIb/IIx, fast glycolytic). Muscle fibre composition switch is closely associated with chronic diseases such as muscle atrophy, obesity, type II diabetes and athletic performance. Prostaglandin D (PGD ) is a bioactive lipid derived from arachidonic acid that aggravates muscle damage and wasting during muscle atrophy.
View Article and Find Full Text PDFiScience
January 2022
Inserm U1016, Institut Cochin, F-75014 Paris, France.
Adult skeletal muscle is a plastic tissue that can adapt its size to workload. Here, we show that RhoA within myofibers is needed for overload-induced hypertrophy by controlling satellite cell (SC) fusion to the growing myofibers without affecting protein synthesis. At the molecular level, we demonstrate that RhoA controls in a cell autonomous manner Erk1/2 activation and the expressions of extracellular matrix (ECM) regulators such as and macrophage chemo-attractants such as / Their decreased expression in RhoA mutants is associated with ECM and fibrillar collagen disorganization and lower macrophage infiltration.
View Article and Find Full Text PDFCell Death Discov
January 2022
Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, 430072, Wuhan, Hubei, China.
Serum response factor (SRF) regulates differentiation and proliferation by binding to RhoA-actin-activated MKL or Ras-MAPK-activated ELK transcriptional coactivators, but the molecular mechanisms responsible for SRF regulation remain unclear. Here, we show that Nemo-like kinase (NLK) is required for the promotion of SRF/ELK signaling in human and mouse cells. NLK was found to interact with and phosphorylate SRF at serine residues 101/103, which in turn enhanced the association between SRF and ELK.
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