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Douglas CM, Bird JE, Kopinke D, Esser KA. An optimized approach to study nanoscale sarcomere structure utilizing super-resolution microscopy with nanobodies. PLoS One 2024; 19:e0300348. [PMID: 38687705 PMCID: PMC11060602 DOI: 10.1371/journal.pone.0300348] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2023] [Accepted: 02/23/2024] [Indexed: 05/02/2024] Open
Abstract
The sarcomere is the fundamental contractile unit in skeletal muscle, and the regularity of its structure is critical for function. Emerging data demonstrates that nanoscale changes to the regularity of sarcomere structure can affect the overall function of the protein dense ~2μm sarcomere. Further, sarcomere structure is implicated in many clinical conditions of muscle weakness. However, our understanding of how sarcomere structure changes in disease, especially at the nanoscale, has been limited in part due to the inability to robustly detect and measure at sub-sarcomere resolution. We optimized several methodological steps and developed a robust pipeline to analyze sarcomere structure using structured illumination super-resolution microscopy in conjunction with commercially-available and fluorescently-conjugated Variable Heavy-Chain only fragment secondary antibodies (nanobodies), and achieved a significant increase in resolution of z-disc width (353nm vs. 62nm) compared to confocal microscopy. The combination of these methods provides a unique approach to probe sarcomere protein localization at the nanoscale and may prove advantageous for analysis of other cellular structures.
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Affiliation(s)
- Collin M. Douglas
- Department of Physiology and Aging, University of Florida, Gainesville, Florida, United States of America
| | - Jonathan E. Bird
- Department of Pharmacology and Therapeutics, University of Florida, Gainesville, Florida, United States of America
| | - Daniel Kopinke
- Department of Pharmacology and Therapeutics, University of Florida, Gainesville, Florida, United States of America
| | - Karyn A. Esser
- Department of Physiology and Aging, University of Florida, Gainesville, Florida, United States of America
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Dominici C, Villarreal OD, Dort J, Heckel E, Wang YC, Ragoussis I, Joyal JS, Dumont N, Richard S. Inhibition of type I PRMTs reforms muscle stem cell identity enhancing their therapeutic capacity. eLife 2023; 12:84570. [PMID: 37285284 DOI: 10.7554/elife.84570] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023] Open
Abstract
In skeletal muscle, muscle stem cells (MuSC) are the main cells responsible for regeneration upon injury. In diseased skeletal muscle, it would be therapeutically advantageous to replace defective MuSCs, or rejuvenate them with drugs to enhance their self-renewal and ensure long-term regenerative potential. One limitation of the replacement approach has been the inability to efficiently expand MuSCs ex vivo, while maintaining their stemness and engraftment abilities. Herein, we show that inhibition of type I protein arginine methyltransferases (PRMTs) with MS023 increases the proliferative capacity of ex vivo cultured MuSCs. Single cell RNA sequencing (scRNAseq) of ex vivo cultured MuSCs revealed the emergence of subpopulations in MS023-treated cells which are defined by elevated Pax7 expression and markers of MuSC quiescence, both features of enhanced self-renewal. Furthermore, the scRNAseq identified MS023-specific subpopulations to be metabolically altered with upregulated glycolysis and oxidative phosphorylation (OxPhos). Transplantation of MuSCs treated with MS023 had a better ability to repopulate the MuSC niche and contributed efficiently to muscle regeneration following injury. Interestingly, the preclinical mouse model of Duchenne muscular dystrophy had increased grip strength with MS023 treatment. Our findings show that inhibition of type I PRMTs increased the proliferation capabilities of MuSCs with altered cellular metabolism, while maintaining their stem-like properties such as self-renewal and engraftment potential.
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Affiliation(s)
- Claudia Dominici
- Segal Cancer Center, Lady Davis Institute for Medical Research, McGill University, Montreal, Canada
- Departments of Human Genetics, McGill University, Montreal, Canada
| | - Oscar D Villarreal
- Segal Cancer Center, Lady Davis Institute for Medical Research, McGill University, Montreal, Canada
| | - Junio Dort
- CHU Sainte-Justine Research Center, Université de Montréal, Montréal, Canada
| | - Emilie Heckel
- CHU Sainte-Justine Research Center, Université de Montréal, Montréal, Canada
| | | | | | | | - Nicolas Dumont
- CHU Sainte-Justine Research Center, Université de Montréal, Montréal, Canada
| | - Stéphane Richard
- Segal Cancer Center, Lady Davis Institute for Medical Research, McGill University, Montreal, Canada
- Departments of Human Genetics, McGill University, Montreal, Canada
- Gerald Bronfman, Department of Oncology, McGill University, Montréal, Canada
- Departments of Medicine, McGill University, Montreal, Canada
- Departments of Biochemistry, McGill University, Montréal, Canada
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Abstract
Senescence is a cell fate that contributes to multiple aging-related pathologies. Despite profound age-associated changes in skeletal muscle (SkM), whether its constituent cells are prone to senesce has not been methodically examined. Herein, using single cell and bulk RNA-sequencing and complementary imaging methods on SkM of young and old mice, we demonstrate that a subpopulation of old fibroadipogenic progenitors highly expresses p16 Ink4a together with multiple senescence-related genes and, concomitantly, exhibits DNA damage and chromatin reorganization. Through analysis of isolated myofibers, we also detail a senescence phenotype within a subset of old cells, governed instead by p2 Cip1 . Administration of a senotherapeutic intervention to old mice countered age-related molecular and morphological changes and improved SkM strength. Finally, we found that the senescence phenotype is conserved in SkM from older humans. Collectively, our data provide compelling evidence for cellular senescence as a hallmark and potentially tractable mediator of SkM aging.
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Dominici C, Richard S. Muscle stem cell polarity requires QKI-mediated alternative splicing of Integrin Alpha-7 (Itga7). Life Sci Alliance 2022; 5:5/5/e202101192. [PMID: 35165120 PMCID: PMC8860092 DOI: 10.26508/lsa.202101192] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Revised: 01/18/2022] [Accepted: 01/19/2022] [Indexed: 12/30/2022] Open
Abstract
The RNA-binding protein Quaking (QKI) is a post-transcriptional regulator of genes encoding polarity proteins in muscle stem cells. Loss of QKI in MuSCs results in reduced myogenic progenitors and a striking muscle regeneration defect. Muscle stem cells (MuSCs) have the ability to carry out the specialized function of cell polarization, which is required for the production of one repopulating cell and one myogenic progenitor cell with muscle regeneration capabilities. The mechanisms which regulate proteins involved in establishing MuSC polarity such as Dmd and Itga7 are currently not well understood. Herein, we define the RNA-binding protein Quaking (QKI) as a major regulator alternative splicing of key MuSC polarity factors including Dmd, Itga7, Mark2, and Numb. We generate a conditional QKI knockout mouse, and for the first time it is shown in vivo that deficiency of QKI in MuSCs results in reduced asymmetric cell divisions, leading to a loss of the myogenic progenitor cell population and striking muscle regeneration defects. Transcriptomic analysis of QKI-deficient MuSCs identifies QKI as a regulator of the splicing events which give rise to the mutually exclusive Itga7-X1 and -X2 isoforms. We observe increased X1 expression in QKI-deficient MuSCs and recapitulate this splicing event using antisense oligonucleotide directed against a quaking binding site within the Itga7 mRNA. Interestingly, recreating this single splicing event is detrimental to the polarization of Itga7 and Dmd proteins, and leads to a drastic reduction of the myogenic progenitor population, highlighting the significance of QKI-mediated alternative splicing of Itga7 in maintaining MuSC polarity. Altogether, these findings define a novel role for QKI as a post-transcriptional regulator of MuSC polarity.
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Affiliation(s)
- Claudia Dominici
- Segal Cancer Center, Lady Davis Institute for Medical Research and Gerald Bronfman Department of Oncology and Departments of Medicine, Human Genetics and Biochemistry, McGill University, Montréal, Québec, Canada
| | - Stéphane Richard
- Segal Cancer Center, Lady Davis Institute for Medical Research and Gerald Bronfman Department of Oncology and Departments of Medicine, Human Genetics and Biochemistry, McGill University, Montréal, Québec, Canada
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Sex differences in metabolic pathways are regulated by Pfkfb3 and Pdk4 expression in rodent muscle. Commun Biol 2021; 4:1264. [PMID: 34737380 PMCID: PMC8569015 DOI: 10.1038/s42003-021-02790-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Accepted: 10/15/2021] [Indexed: 12/28/2022] Open
Abstract
Skeletal muscles display sexually dimorphic features. Biochemically, glycolysis and fatty acid β-oxidation occur preferentially in the muscles of males and females, respectively. However, the mechanisms of the selective utilization of these fuels remains elusive. Here, we obtain transcriptomes from quadriceps type IIB fibers of untreated, gonadectomized, and sex steroid-treated mice of both sexes. Analyses of the transcriptomes unveil two genes, Pfkfb3 (phosphofructokinase-2) and Pdk4 (pyruvate dehydrogenase kinase 4), that may function as switches between the two sexually dimorphic metabolic pathways. Interestingly, Pfkfb3 and Pdk4 show male-enriched and estradiol-enhanced expression, respectively. Moreover, the contribution of these genes to sexually dimorphic metabolism is demonstrated by knockdown studies with cultured type IIB muscle fibers. Considering that skeletal muscles as a whole are the largest energy-consuming organs, our results provide insights into energy metabolism in the two sexes, during the estrus cycle in women, and under pathological conditions involving skeletal muscles. Baba et al. analyzed the transcriptomes from quadriceps type IIB fibers of untreated, gonadectomized, and sex steroid-treated mice of both sexes and identified Pfkfb3 and Pdk4 as differentially regulated genes between males and diestrus females. The authors found that Pfkfb3 and Pdk4 may act as metabolic switches, showed male-enriched and estradiol-enhanced expression, respectively and contributed to sexually dimorphic metabolism.
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Muscle regeneration controlled by a designated DNA dioxygenase. Cell Death Dis 2021; 12:535. [PMID: 34035232 PMCID: PMC8149877 DOI: 10.1038/s41419-021-03817-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Revised: 04/27/2021] [Accepted: 05/07/2021] [Indexed: 12/27/2022]
Abstract
Tet dioxygenases are responsible for the active DNA demethylation. The functions of Tet proteins in muscle regeneration have not been well characterized. Here we find that Tet2, but not Tet1 and Tet3, is specifically required for muscle regeneration in vivo. Loss of Tet2 leads to severe muscle regeneration defects. Further analysis indicates that Tet2 regulates myoblast differentiation and fusion. Tet2 activates transcription of the key differentiation modulator Myogenin (MyoG) by actively demethylating its enhancer region. Re-expressing of MyoG in Tet2 KO myoblasts rescues the differentiation and fusion defects. Further mechanistic analysis reveals that Tet2 enhances MyoD binding by demethylating the flanking CpG sites of E boxes to facilitate the recruitment of active histone modifications and increase chromatin accessibility and activate its transcription. These findings shed new lights on DNA methylation and pioneer transcription factor activity regulation.
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Stange K, Ahrens HE, von Maltzahn J, Röntgen M. Isolation and ex vivo cultivation of single myofibers from porcine muscle. In Vitro Cell Dev Biol Anim 2020; 56:585-592. [PMID: 32964376 PMCID: PMC7532130 DOI: 10.1007/s11626-020-00492-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Accepted: 08/06/2020] [Indexed: 11/27/2022]
Abstract
The isolation and cultivation of intact, single myofibers presents a superior approach for studying myogenic cells in their native position. The cells’ characteristics remain more similar to muscle tissue than in cell culture. Nevertheless, no routinely used method in higher vertebrates exists. Therefore, we aimed at establishing the isolation and cultivation of single myofibers from porcine muscle. For the first time, we implemented the isolation of intact myofibers from porcine fibularis tertius muscle by enzymatic digestion and their subsequent cultivation under floating conditions. Confocal microscopy showed intact myofibrill structures in isolated myofibers. Myogenic cells were able to proliferate at their parent myofiber as shown by the increase of myonuclear number during culture. Additionally, the described method can be used to investigate myogenic cells migrated from isolated myofibers. These cells expressed myogenic markers and were able to differentiate. In the future, our method can be used for genetic manipulation of cells at myofibers, investigation of growth factors or pharmacological substances, and determination of interactions between myofibers and associated cells. Working with isolated myofibers has the potential to bridge conventional cell culture and animal experiments. Adapting the method to porcine muscle allows for application possibilities in veterinary medicine as well as in biomedical research, which cannot be addressed in rodent model systems.
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Affiliation(s)
- Katja Stange
- Institute of Muscle Biology and Growth, Growth and Development Unit, Leibniz Institute for Farm Animal Biology (FBN), Wilhelm-Stahl-Allee 2, 18196, Dummerstorf, Germany
| | - Hellen Elisa Ahrens
- Research Group Stem Cells in Regeneration of Skeletal Muscle, Leibniz Institute on Aging, 07745, Jena, Germany
| | - Julia von Maltzahn
- Research Group Stem Cells in Regeneration of Skeletal Muscle, Leibniz Institute on Aging, 07745, Jena, Germany
| | - Monika Röntgen
- Institute of Muscle Biology and Growth, Growth and Development Unit, Leibniz Institute for Farm Animal Biology (FBN), Wilhelm-Stahl-Allee 2, 18196, Dummerstorf, Germany.
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Kallabis S, Abraham L, Müller S, Dzialas V, Türk C, Wiederstein JL, Bock T, Nolte H, Nogara L, Blaauw B, Braun T, Krüger M. High-throughput proteomics fiber typing (ProFiT) for comprehensive characterization of single skeletal muscle fibers. Skelet Muscle 2020; 10:7. [PMID: 32293536 PMCID: PMC7087369 DOI: 10.1186/s13395-020-00226-5] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Accepted: 03/04/2020] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Skeletal muscles are composed of a heterogeneous collection of fiber types with different physiological adaption in response to a stimulus and disease-related conditions. Each fiber has a specific molecular expression of myosin heavy chain molecules (MyHC). So far, MyHCs are currently the best marker proteins for characterization of individual fiber types, and several proteome profiling studies have helped to dissect the molecular signature of whole muscles and individual fibers. METHODS Herein, we describe a mass spectrometric workflow to measure skeletal muscle fiber type-specific proteomes. To bypass the limited quantities of protein in single fibers, we developed a Proteomics high-throughput fiber typing (ProFiT) approach enabling profiling of MyHC in single fibers. Aliquots of protein extracts from separated muscle fibers were subjected to capillary LC-MS gradients to profile MyHC isoforms in a 96-well format. Muscle fibers with the same MyHC protein expression were pooled and subjected to proteomic, pulsed-SILAC, and phosphoproteomic analysis. RESULTS Our fiber type-specific quantitative proteome analysis confirmed the distribution of fiber types in the soleus muscle, substantiates metabolic adaptions in oxidative and glycolytic fibers, and highlighted significant differences between the proteomes of type IIb fibers from different muscle groups, including a differential expression of desmin and actinin-3. A detailed map of the Lys-6 incorporation rates in muscle fibers showed an increased turnover of slow fibers compared to fast fibers. In addition, labeling of mitochondrial respiratory chain complexes revealed a broad range of Lys-6 incorporation rates, depending on the localization of the subunits within distinct complexes. CONCLUSION Overall, the ProFiT approach provides a versatile tool to rapidly characterize muscle fibers and obtain fiber-specific proteomes for different muscle groups.
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Affiliation(s)
- Sebastian Kallabis
- CECAD Research Center, Institute for Genetics, University of Cologne, 50931, Cologne, Germany
| | - Lena Abraham
- CECAD Research Center, Institute for Genetics, University of Cologne, 50931, Cologne, Germany
| | - Stefan Müller
- CECAD Research Center, Institute for Genetics, University of Cologne, 50931, Cologne, Germany
| | - Verena Dzialas
- CECAD Research Center, Institute for Genetics, University of Cologne, 50931, Cologne, Germany
| | - Clara Türk
- CECAD Research Center, Institute for Genetics, University of Cologne, 50931, Cologne, Germany
| | - Janica Lea Wiederstein
- CECAD Research Center, Institute for Genetics, University of Cologne, 50931, Cologne, Germany
| | - Theresa Bock
- CECAD Research Center, Institute for Genetics, University of Cologne, 50931, Cologne, Germany
| | - Hendrik Nolte
- Max Planck Institute for the Biology of Aging, 50931, Cologne, Germany
| | - Leonardo Nogara
- Venetian Institute of Molecular Medicine (VIMM), Via Orus 2, 35129, Padova, Italy
| | - Bert Blaauw
- Venetian Institute of Molecular Medicine (VIMM), Via Orus 2, 35129, Padova, Italy
| | - Thomas Braun
- Max Planck Institute for Heart and Lung Research, 61231, Bad Nauheim, Germany
| | - Marcus Krüger
- CECAD Research Center, Institute for Genetics, University of Cologne, 50931, Cologne, Germany. .,Center for Molecular Medicine (CMMC), University of Cologne, 50931, Cologne, Germany.
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Smith LR, Meyer GA. Skeletal muscle explants: ex-vivo models to study cellular behavior in a complex tissue environment. Connect Tissue Res 2020; 61:248-261. [PMID: 31492079 PMCID: PMC8837600 DOI: 10.1080/03008207.2019.1662409] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Purpose/Aim: Skeletal muscle tissue explants have been cultured and studied for nearly 100 years. These cultures, which retain complex tissue structure in an environment suited to precision manipulation and measurement, have led to seminal discoveries of the extrinsic and intrinsic mechanisms regulating contractility, metabolism and regeneration. This review discusses the two primary models of muscle explant: isolated myofiber and intact muscle.Materials and Methods: Relevant literature was reviewed and synthesized with a focus on the unique challenges and capabilities of each explant model.Results: Impactful past, current and future novel applications are discussed.Conclusions: Experiments using skeletal muscle explants have been integral to our understanding of the fundamentals of muscle physiology. As they are refined and adapted, they are poised to continue to inform the field for years to come.
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Affiliation(s)
- Lucas R. Smith
- Departments of Neurobiology, Physiology and Behavior and Physical Medicine and Rehabilitation, University of California, Davis; Davis, CA 95616
| | - Gretchen A. Meyer
- Program in Physical Therapy and Departments of Neurology, Biomedical Engineering and Orthopaedic Surgery, Washington University in St. Louis; St. Louis, MO 63110
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Chen S, Ding H, Yao X, Xie L. Isolation and Culture of Single Myofiber and Immunostaining of Satellite Cells from Adult C57BL/6J Mice. Bio Protoc 2019; 9:e3313. [PMID: 33654822 DOI: 10.21769/bioprotoc.3313] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Revised: 06/28/2019] [Accepted: 06/30/2019] [Indexed: 11/02/2022] Open
Abstract
Myofiber isolation followed with ex vivo culture could recapitulate and visualize satellite cells (SCs) activation, proliferation, and differentiation. This approach could be taken to understand the physiology of satellite cells and the molecular mechanism of regulatory factors, in terms of the involvement of intrinsic factors over SCs quiescence, activation, proliferation and differentiation. Single myofiber culture has several advantages that the traditional approach such as FASC and cryosection could not compete with. For example, myofiber isolation and culture could be used to observe SCs activation, proliferation and differentiation at a continuous manner within their physiological "niche" environment while FACS or cryosection could only capture single time-point upon external stimulation to activate satellite cells by BaCl2, Cardiotoxin or ischemia. Furthermore, in vitro transfection with siRNA or overexpression vector could be performed under ex vivo culture to understand the detailed molecular function of a specific gene on SCs physiology. With these advantages, the physiological state of SCs could be analyzed at multiple designated time-points by immunofluorescence staining. In this protocol, we provide an efficient and practical protocol to isolate single myofiber from EDL muscle, followed with ex vivo culture and immunostaining.
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Affiliation(s)
- Shujie Chen
- State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Open Laboratory of Applied Microbiology, Guangdong Institute of Microbiology, Guangdong Academy of Sciences, Guangdong 510070, China
| | - Hongrong Ding
- State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Open Laboratory of Applied Microbiology, Guangdong Institute of Microbiology, Guangdong Academy of Sciences, Guangdong 510070, China
| | - Xiangping Yao
- State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Open Laboratory of Applied Microbiology, Guangdong Institute of Microbiology, Guangdong Academy of Sciences, Guangdong 510070, China.,Zhujiang Hospital, Southern Medical University, Guangdong 510282, China
| | - Liwei Xie
- State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Open Laboratory of Applied Microbiology, Guangdong Institute of Microbiology, Guangdong Academy of Sciences, Guangdong 510070, China.,Zhujiang Hospital, Southern Medical University, Guangdong 510282, China
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Loss of microRNA-23-27-24 clusters in skeletal muscle is not influential in skeletal muscle development and exercise-induced muscle adaptation. Sci Rep 2019; 9:1092. [PMID: 30705375 PMCID: PMC6355808 DOI: 10.1038/s41598-018-37765-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Accepted: 12/06/2018] [Indexed: 01/21/2023] Open
Abstract
MicroRNAs are small regulatory noncoding RNAs that repress gene expression at the posttranscriptional level. Previous studies have reported that the expression of miR-23, miR-27, and miR-24, driven from two miR-23–27–24 clusters, is altered by various pathophysiological conditions. However, their functions in skeletal muscle have not been clarified. To define the roles of the miR-23–27–24 clusters in skeletal muscle, we generated double-knockout (dKO) mice muscle-specifically lacking the miR-23–27–24 clusters. The dKO mice were viable and showed normal growth. The contractile and metabolic features of the muscles, represented by the expression of the myosin heavy chain and the oxidative markers PGC1-α and COX IV, were not altered in the dKO mice compared with wild-type mice. The dKO mice showed increased cross-sectional areas of the oxidative fibers. However, this dKO did not induce functional changes in the muscles. The dKO mice also showed normal adaptation to voluntary wheel running for 4 weeks, including the glycolytic-to-oxidative fiber type switch, and increases in mitochondrial markers, succinate dehydrogenase activity, and angiogenesis. In conclusion, our data demonstrate that the miR-23–27–24 clusters have subtle effects on skeletal muscle development and endurance-exercise-induced muscle adaptation.
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12
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The RNA-binding proteins Zfp36l1 and Zfp36l2 act redundantly in myogenesis. Skelet Muscle 2018; 8:37. [PMID: 30526691 PMCID: PMC6286576 DOI: 10.1186/s13395-018-0183-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Accepted: 11/22/2018] [Indexed: 01/07/2023] Open
Abstract
Background Members of the ZFP36 family of RNA-binding proteins regulate gene expression post-transcriptionally by binding to AU-rich elements in the 3’UTR of mRNA and stimulating mRNA degradation. The proteins within this family target different transcripts in different tissues. In particular, ZFP36 targets myogenic transcripts and may have a role in adult muscle stem cell quiescence. Our study examined the requirement of ZFP36L1 and ZFP36L2 in adult muscle cell fate regulation. Methods We generated single and double conditional knockout mice in which Zfp36l1 and/or Zfp36l2 were deleted in Pax7-expressing cells. Immunostained muscle sections were used to analyse resting skeletal muscle, and a cardiotoxin-induced injury model was used to determine the regenerative capacity of muscle. Results We show that ZFP36L1 and ZFP36L2 proteins are expressed in satellite cells. Mice lacking the two proteins in Pax7-expressing cells have reduced body weight and have reduced skeletal muscle mass. Furthermore, the number of satellite cells is reduced in adult skeletal muscle and the capacity of this muscle to regenerate following muscle injury is diminished. Conclusion ZFP36L1 and ZFP36L2 act redundantly in myogenesis. These findings add further intricacy to the regulation of the cell fate of Pax7-expressing cells in skeletal muscle by RNA-binding proteins. Electronic supplementary material The online version of this article (10.1186/s13395-018-0183-9) contains supplementary material, which is available to authorized users.
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Renzini A, Benedetti A, Bouchè M, Silvestroni L, Adamo S, Moresi V. Culture conditions influence satellite cell activation and survival of single myofibers. Eur J Transl Myol 2018; 28:7567. [PMID: 29991990 PMCID: PMC6036316 DOI: 10.4081/ejtm.2018.7567] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Revised: 05/24/2018] [Accepted: 05/24/2018] [Indexed: 02/08/2023] Open
Abstract
Single myofiber isolation protocols allow to obtain an in vitro system in which the physical association between the myofiber and its stem cells, the satellite cells, is adequately preserved. This technique is an indispensable tool by which the muscle regeneration process can be recapitulated and studied in each specific phase, from satellite cell activation to proliferation, from differentiation to fusion. This study aims to clarify the effect of different culture conditions on single myofibers, their associated satellite cells, and the physiological behavior of the satellite cells upon long term culture. By direct observations of the cultures, we compared different experimental conditions and their effect on both satellite cell behavior and myofiber viability.
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Affiliation(s)
- Alessandra Renzini
- DAHFMO Unit of Histology and Medical Embryology, InterUniversity Institute of Myology, Sapienza University of Rome, Italy
| | - Anna Benedetti
- DAHFMO Unit of Histology and Medical Embryology, InterUniversity Institute of Myology, Sapienza University of Rome, Italy
| | - Marina Bouchè
- DAHFMO Unit of Histology and Medical Embryology, InterUniversity Institute of Myology, Sapienza University of Rome, Italy
| | - Leopoldo Silvestroni
- Department of Fundamental and Basic Sciences for Engineering, Sapienza University of Rome, Italy
| | - Sergio Adamo
- DAHFMO Unit of Histology and Medical Embryology, InterUniversity Institute of Myology, Sapienza University of Rome, Italy
| | - Viviana Moresi
- DAHFMO Unit of Histology and Medical Embryology, InterUniversity Institute of Myology, Sapienza University of Rome, Italy
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14
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Zhang L, Gong H, Sun Q, Zhao R, Jia Y. Spermidine-Activated Satellite Cells Are Associated with Hypoacetylation in ACVR2B and Smad3 Binding to Myogenic Genes in Mice. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2018; 66:540-550. [PMID: 29224337 DOI: 10.1021/acs.jafc.7b04482] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Spermidine is an acetyltransferase inhibitor and a specific inducer of autophagy. Recently, spermidine is identified as a potential therapeutic agent for age-related muscle atrophy and inherited myopathies. However, the effect of spermidine on nonpathological skeletal muscle remains unclear. In this study, long-term spermidine administration in mice lowered the mean cross-sectional area of the gastrocnemius muscle and reduced the expression of myosin heavy chain isoforms in the muscle, which was associated with ubiquitination. Moreover, spermidine supplementation induced autophagy in satellite cells and enhanced satellite cell proliferation. ChIP assay revealed that spermidine repressed H3K56ac in the promoter of ACVR2B and lowered the binding affinity of Smad3 to the promoters of Myf5 and MyoD. Altogether, our results indicate that long-term administration of spermidine can activate satellite cells, as well as enhance autophagy, eventually resulting in muscle atrophy. In addition, H3K56ac and Smad3 emerged as key determinants of satellite cell activation.
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Affiliation(s)
- Luchu Zhang
- Key Laboratory of Animal Physiology & Biochemistry, College of Veterinary Medicine, Nanjing Agricultural University , Nanjing 210095, P. R. China
| | - Huiying Gong
- Key Laboratory of Animal Physiology & Biochemistry, College of Veterinary Medicine, Nanjing Agricultural University , Nanjing 210095, P. R. China
| | - Qinwei Sun
- Key Laboratory of Animal Physiology & Biochemistry, College of Veterinary Medicine, Nanjing Agricultural University , Nanjing 210095, P. R. China
| | - Ruqian Zhao
- Key Laboratory of Animal Physiology & Biochemistry, College of Veterinary Medicine, Nanjing Agricultural University , Nanjing 210095, P. R. China
- Quality and Safety Control, Jiangsu Collaborative Innovation Center of Meat Production and Processing , Nanjing 210095, P. R. China
| | - Yimin Jia
- Key Laboratory of Animal Physiology & Biochemistry, College of Veterinary Medicine, Nanjing Agricultural University , Nanjing 210095, P. R. China
- Quality and Safety Control, Jiangsu Collaborative Innovation Center of Meat Production and Processing , Nanjing 210095, P. R. China
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15
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Hindi SM, Shin J, Gallot YS, Straughn AR, Simionescu-Bankston A, Hindi L, Xiong G, Friedland RP, Kumar A. MyD88 promotes myoblast fusion in a cell-autonomous manner. Nat Commun 2017; 8:1624. [PMID: 29158520 PMCID: PMC5696367 DOI: 10.1038/s41467-017-01866-w] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Accepted: 10/20/2017] [Indexed: 12/27/2022] Open
Abstract
Myoblast fusion is an indispensable step for skeletal muscle development, postnatal growth, and regeneration. Myeloid differentiation primary response gene 88 (MyD88) is an adaptor protein that mediates Toll-like receptors and interleukin-1 receptor signaling. Here we report a cell-autonomous role of MyD88 in the regulation of myoblast fusion. MyD88 protein levels are increased during in vitro myogenesis and in conditions that promote skeletal muscle growth in vivo. Deletion of MyD88 impairs fusion of myoblasts without affecting their survival, proliferation, or differentiation. MyD88 regulates non-canonical NF-κB and canonical Wnt signaling during myogenesis and promotes skeletal muscle growth and overload-induced myofiber hypertrophy in mice. Ablation of MyD88 reduces myofiber size during muscle regeneration, whereas its overexpression promotes fusion of exogenous myoblasts to injured myofibers. Our study shows that MyD88 modulates myoblast fusion and suggests that augmenting its levels may be a therapeutic approach to improve skeletal muscle formation in degenerative muscle disorders.
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Affiliation(s)
- Sajedah M Hindi
- Department of Anatomical Sciences and Neurobiology, University of Louisville School of Medicine, Louisville, KY, 40202, USA
| | - Jonghyun Shin
- Department of Anatomical Sciences and Neurobiology, University of Louisville School of Medicine, Louisville, KY, 40202, USA
| | - Yann S Gallot
- Department of Anatomical Sciences and Neurobiology, University of Louisville School of Medicine, Louisville, KY, 40202, USA
| | - Alex R Straughn
- Department of Anatomical Sciences and Neurobiology, University of Louisville School of Medicine, Louisville, KY, 40202, USA
| | - Adriana Simionescu-Bankston
- Department of Anatomical Sciences and Neurobiology, University of Louisville School of Medicine, Louisville, KY, 40202, USA
| | - Lubna Hindi
- Department of Anatomical Sciences and Neurobiology, University of Louisville School of Medicine, Louisville, KY, 40202, USA
| | - Guangyan Xiong
- Department of Anatomical Sciences and Neurobiology, University of Louisville School of Medicine, Louisville, KY, 40202, USA
| | - Robert P Friedland
- Department of Neurology, University of Louisville School of Medicine, Louisville, KY, 40202, USA
| | - Ashok Kumar
- Department of Anatomical Sciences and Neurobiology, University of Louisville School of Medicine, Louisville, KY, 40202, USA.
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