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Nolan A, Heaton RA, Adamova P, Cole P, Turton N, Gillham SH, Owens DJ, Sexton DW. Fluorescent characterization of differentiated myotubes using flow cytometry. Cytometry A 2024; 105:332-344. [PMID: 38092660 DOI: 10.1002/cyto.a.24822] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2023] [Revised: 10/23/2023] [Accepted: 12/11/2023] [Indexed: 12/27/2023]
Abstract
Flow cytometry is routinely used in the assessment of skeletal muscle progenitor cell (myoblast) populations. However, a full gating strategy, inclusive of difficult to interpret forward and side scatter data, which documents cytometric analysis of differentiated myoblasts (myotubes) has not been reported. Beyond changes in size and shape, there are substantial metabolic and protein changes in myotubes allowing for their potential identification within heterogenous cell suspensions. To establish the utility of flow cytometry for determination of myoblasts and myotubes, C2C12 murine cell populations were assessed for cell morphology and metabolic reprogramming. Laser scatter, both forward (FSC; size) and side (SSC; granularity), measured cell morphology, while mitochondrial mass, reactive oxygen species (ROS) generation and DNA content were quantified using the fluorescent probes, MitoTracker green, CM-H2DCFDA and Vybrant DyeCycle, respectively. Immunophenotyping for myosin heavy chain (MyHC) was utilized to confirm myotube differentiation. Cellular viability was determined using Annexin V/propidium iodide dual labelling. Fluorescent microscopy was employed to visualize fluorescence and morphology. Myotube and myoblast populations were resolvable through non-intuitive interpretation of laser scatter-based morphology assessment and mitochondrial mass and activity assessment. Myotubes appeared to have similar sizes to the myoblasts based on laser scatter but exhibited greater mitochondrial mass (159%, p < 0.0001), ROS production (303%, p < 0.0001), DNA content (18%, p < 0.001) and expression of MyHC (147%, p < 0.001) compared to myoblasts. Myotube sub-populations contained a larger viable cluster of cells which were unable to be fractionated from myoblast populations and a smaller population cluster which likely contains apoptotic bodies. Imaging of differentiated myoblasts that had transited through the flow cytometer revealed the presence of intact, 'rolled-up' myotubes, which would alter laser scatter properties and potential transit through the laser beam. Our results indicate that myotubes can be analyzed successfully using flow cytometry. Increased mitochondrial mass, ROS and DNA content are key features that correlate with MyHC expression but due to myotubes 'rolling up' during flow cytometric analysis, laser scatter determination of size is not positively correlated; a phenomenon observed with some size determination particles and related to surface properties of said particles. We also note a greater heterogeneity of myotubes compared to myoblasts as evidenced by the 2 distinct sub-populations. We suggest that acoustic focussing may prove effective in identifying myotube sub populations compared to traditional hydrodynamic focussing.
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Affiliation(s)
- Andy Nolan
- Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, UK
- Institute of Life Course and Medical Sciences, University of Liverpool, Liverpool, UK
| | - Robert A Heaton
- Institute of Life Course and Medical Sciences, University of Liverpool, Liverpool, UK
| | - Petra Adamova
- School of Pharmacy and Biomolecular Sciences, Liverpool John Moores University, Liverpool, UK
| | - Paige Cole
- Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, UK
| | - Nadia Turton
- School of Pharmacy and Biomolecular Sciences, Liverpool John Moores University, Liverpool, UK
| | - Scott H Gillham
- Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, UK
| | - Daniel J Owens
- Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, UK
| | - Darren W Sexton
- School of Pharmacy and Biomolecular Sciences, Liverpool John Moores University, Liverpool, UK
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Bou Akar R, Lama C, Aubin D, Maruotti J, Onteniente B, Esteves de Lima J, Relaix F. Generation of highly pure pluripotent stem cell-derived myogenic progenitor cells and myotubes. Stem Cell Reports 2024; 19:84-99. [PMID: 38101399 PMCID: PMC10828960 DOI: 10.1016/j.stemcr.2023.11.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2023] [Revised: 11/14/2023] [Accepted: 11/15/2023] [Indexed: 12/17/2023] Open
Abstract
Driving efficient and pure skeletal muscle cell differentiation from pluripotent stem cells (PSCs) has been challenging. Here, we report an optimized protocol that generates skeletal muscle progenitor cells with high efficiency and purity in a short period of time. Human induced PSCs (hiPSCs) and murine embryonic stem cells (mESCs) were specified into the mesodermal myogenic fate using distinct and species-specific protocols. We used a specific maturation medium to promote the terminal differentiation of both human and mouse myoblast populations, and generated myotubes associated with a large pool of cell-cycle arrested PAX7+ cells. We also show that myotube maturation is modulated by dish-coating properties, cell density, and percentage of myogenic progenitor cells. Given the high efficiency in the generation of myogenic progenitors and differentiated myofibers, this protocol provides an attractive strategy for tissue engineering, modeling of muscle dystrophies, and evaluation of new therapeutic approaches in vitro.
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Affiliation(s)
- Reem Bou Akar
- University Paris Est Creteil, INSERM, EnvA, EFS, AP-HP, IMRB, 94010 Creteil, France
| | - Chéryane Lama
- University Paris Est Creteil, INSERM, EnvA, EFS, AP-HP, IMRB, 94010 Creteil, France
| | | | | | | | | | - Frédéric Relaix
- University Paris Est Creteil, INSERM, EnvA, EFS, AP-HP, IMRB, 94010 Creteil, France.
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3
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van der Wal E, Iuliano A, In 't Groen SLM, Bholasing AP, Priesmann D, Sharma P, den Hamer B, Saggiomo V, Krüger M, Pijnappel WWMP, de Greef JC. Highly contractile 3D tissue engineered skeletal muscles from human iPSCs reveal similarities with primary myoblast-derived tissues. Stem Cell Reports 2023; 18:1954-1971. [PMID: 37774701 PMCID: PMC10656354 DOI: 10.1016/j.stemcr.2023.08.014] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Revised: 08/30/2023] [Accepted: 08/31/2023] [Indexed: 10/01/2023] Open
Abstract
Skeletal muscle research is transitioning toward 3D tissue engineered in vitro models reproducing muscle's native architecture and supporting measurement of functionality. Human induced pluripotent stem cells (hiPSCs) offer high yields of cells for differentiation. It has been difficult to differentiate high-quality, pure 3D muscle tissues from hiPSCs that show contractile properties comparable to primary myoblast-derived tissues. Here, we present a transgene-free method for the generation of purified, expandable myogenic progenitors (MPs) from hiPSCs grown under feeder-free conditions. We defined a protocol with optimal hydrogel and medium conditions that allowed production of highly contractile 3D tissue engineered skeletal muscles with forces similar to primary myoblast-derived tissues. Gene expression and proteomic analysis between hiPSC-derived and primary myoblast-derived 3D tissues revealed a similar expression profile of proteins involved in myogenic differentiation and sarcomere function. The protocol should be generally applicable for the study of personalized human skeletal muscle tissue in health and disease.
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Affiliation(s)
- Erik van der Wal
- Department of Human Genetics, Leiden University Medical Center, 2333 ZA Leiden, the Netherlands
| | - Alessandro Iuliano
- Department of Clinical Genetics, Erasmus University Medical Center, 3015 GE Rotterdam, the Netherlands; Department of Pediatrics, Erasmus University Medical Center, 3015 GE Rotterdam, the Netherlands; Center for Lysosomal and Metabolic Diseases, Erasmus University Medical Center, 3015 GE Rotterdam, the Netherlands
| | - Stijn L M In 't Groen
- Department of Clinical Genetics, Erasmus University Medical Center, 3015 GE Rotterdam, the Netherlands; Department of Pediatrics, Erasmus University Medical Center, 3015 GE Rotterdam, the Netherlands; Center for Lysosomal and Metabolic Diseases, Erasmus University Medical Center, 3015 GE Rotterdam, the Netherlands
| | - Anjali P Bholasing
- Department of Clinical Genetics, Erasmus University Medical Center, 3015 GE Rotterdam, the Netherlands; Department of Pediatrics, Erasmus University Medical Center, 3015 GE Rotterdam, the Netherlands; Center for Lysosomal and Metabolic Diseases, Erasmus University Medical Center, 3015 GE Rotterdam, the Netherlands
| | - Dominik Priesmann
- Institute of Genetics and Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany; Center for Molecular Medicine, University of Cologne, Cologne, Germany
| | - Preeti Sharma
- Physical Chemistry and Soft Matter, Wageningen University and Research, 6708 WE Wageningen, the Netherlands
| | - Bianca den Hamer
- Department of Human Genetics, Leiden University Medical Center, 2333 ZA Leiden, the Netherlands
| | - Vittorio Saggiomo
- Department of BioNanoTechnology, Wageningen University and Research, 6708 WG Wageningen, the Netherlands
| | - Marcus Krüger
- Institute of Genetics and Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany; Center for Molecular Medicine, University of Cologne, Cologne, Germany
| | - W W M Pim Pijnappel
- Department of Clinical Genetics, Erasmus University Medical Center, 3015 GE Rotterdam, the Netherlands; Department of Pediatrics, Erasmus University Medical Center, 3015 GE Rotterdam, the Netherlands; Center for Lysosomal and Metabolic Diseases, Erasmus University Medical Center, 3015 GE Rotterdam, the Netherlands.
| | - Jessica C de Greef
- Department of Human Genetics, Leiden University Medical Center, 2333 ZA Leiden, the Netherlands.
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Chien P, Xi H, Pyle AD. Recapitulating human myogenesis ex vivo using human pluripotent stem cells. Exp Cell Res 2021; 411:112990. [PMID: 34973262 DOI: 10.1016/j.yexcr.2021.112990] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Revised: 12/15/2021] [Accepted: 12/22/2021] [Indexed: 11/25/2022]
Abstract
Human pluripotent stem cells (hPSCs) provide a human model for developmental myogenesis, disease modeling and development of therapeutics. Differentiation of hPSCs into muscle stem cells has the potential to provide a cell-based therapy for many skeletal muscle wasting diseases. This review describes the current state of hPSCs towards recapitulating human myogenesis ex vivo, considerations of stem cell and progenitor cell state as well as function for future use of hPSC-derived muscle cells in regenerative medicine.
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Affiliation(s)
- Peggie Chien
- Department of Microbiology, Immunology and Molecular Genetics, Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, Molecular Biology Institute, University of California, Los Angeles, CA, 90095, USA
| | - Haibin Xi
- Department of Microbiology, Immunology and Molecular Genetics, Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, Molecular Biology Institute, University of California, Los Angeles, CA, 90095, USA
| | - April D Pyle
- Department of Microbiology, Immunology and Molecular Genetics, Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, Molecular Biology Institute, University of California, Los Angeles, CA, 90095, USA.
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Kondash ME, Ananthakumar A, Khodabukus A, Bursac N, Truskey GA. Glucose Uptake and Insulin Response in Tissue-engineered Human Skeletal Muscle. Tissue Eng Regen Med 2020; 17:801-813. [PMID: 32200516 DOI: 10.1007/s13770-020-00242-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2019] [Revised: 01/19/2020] [Accepted: 01/21/2020] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND Tissue-engineered muscles ("myobundles") offer a promising platform for developing a human in vitro model of healthy and diseased muscle for drug development and testing. Compared to traditional monolayer cultures, myobundles better model the three-dimensional structure of native skeletal muscle and are amenable to diverse functional measures to monitor the muscle health and drug response. Characterizing the metabolic function of human myobundles is of particular interest to enable their utilization in mechanistic studies of human metabolic diseases, identification of related drug targets, and systematic studies of drug safety and efficacy. METHODS To this end, we studied glucose uptake and insulin responsiveness in human tissue-engineered skeletal muscle myobundles in the basal state and in response to drug treatments. RESULTS In the human skeletal muscle myobundle system, insulin stimulates a 50% increase in 2-deoxyglucose (2-DG) uptake with a compiled EC50 of 0.27 ± 0.03 nM. Treatment of myobundles with 400 µM metformin increased basal 2-DG uptake 1.7-fold and caused a significant drop in twitch and tetanus contractile force along with decreased fatigue resistance. Treatment with the histone deacetylase inhibitor 4-phenylbutyrate (4-PBA) increased the magnitude of insulin response from a 1.2-fold increase in glucose uptake in the untreated state to a 1.4-fold increase after 4-PBA treatment. 4-PBA treated myobundles also exhibited increased fatigue resistance and increased twitch half-relaxation time. CONCLUSION Although tissue-engineered human myobundles exhibit a modest increase in glucose uptake in response to insulin, they recapitulate key features of in vivo insulin sensitivity and exhibit relevant drug-mediated perturbations in contractile function and glucose metabolism.
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Affiliation(s)
- Megan E Kondash
- Department of Biomedical Engineering, Duke University, Durham, NC, 27708, USA
| | | | - Alastair Khodabukus
- Department of Biomedical Engineering, Duke University, Durham, NC, 27708, USA
| | - Nenad Bursac
- Department of Biomedical Engineering, Duke University, Durham, NC, 27708, USA
| | - George A Truskey
- Department of Biomedical Engineering, Duke University, Durham, NC, 27708, USA.
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Selvaraj S, Mondragon-Gonzalez R, Xu B, Magli A, Kim H, Lainé J, Kiley J, Mckee H, Rinaldi F, Aho J, Tabti N, Shen W, Perlingeiro RCR. Screening identifies small molecules that enhance the maturation of human pluripotent stem cell-derived myotubes. eLife 2019; 8:e47970. [PMID: 31710288 PMCID: PMC6845233 DOI: 10.7554/elife.47970] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Accepted: 10/29/2019] [Indexed: 01/14/2023] Open
Abstract
Targeted differentiation of pluripotent stem (PS) cells into myotubes enables in vitro disease modeling of skeletal muscle diseases. Although various protocols achieve myogenic differentiation in vitro, resulting myotubes typically display an embryonic identity. This is a major hurdle for accurately recapitulating disease phenotypes in vitro, as disease commonly manifests at later stages of development. To address this problem, we identified four factors from a small molecule screen whose combinatorial treatment resulted in myotubes with enhanced maturation, as shown by the expression profile of myosin heavy chain isoforms, as well as the upregulation of genes related with muscle contractile function. These molecular changes were confirmed by global chromatin accessibility and transcriptome studies. Importantly, we also observed this maturation in three-dimensional muscle constructs, which displayed improved in vitro contractile force generation in response to electrical stimulus. Thus, we established a model for in vitro muscle maturation from PS cells.
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Affiliation(s)
- Sridhar Selvaraj
- Lillehei Heart Institute, Department of MedicineUniversity of MinnesotaMinneapolisUnited States
| | - Ricardo Mondragon-Gonzalez
- Lillehei Heart Institute, Department of MedicineUniversity of MinnesotaMinneapolisUnited States
- Departamento de Genética y Biología MolecularCentro de Investigación y de Estudios Avanzados del IPN (CINVESTAV-IPN)Ciudad de MéxicoMexico
| | - Bin Xu
- Department of Biomedical EngineeringUniversity of MinnesotaMinneapolisUnited States
| | - Alessandro Magli
- Lillehei Heart Institute, Department of MedicineUniversity of MinnesotaMinneapolisUnited States
- Stem Cell InstituteUniversity of MinnesotaMinneapolisUnited States
| | - Hyunkee Kim
- Lillehei Heart Institute, Department of MedicineUniversity of MinnesotaMinneapolisUnited States
| | - Jeanne Lainé
- Département de PhysiologieSorbonne Universités, Faculté de Médecine site Pitié-SalpêtrièreParisFrance
| | - James Kiley
- Lillehei Heart Institute, Department of MedicineUniversity of MinnesotaMinneapolisUnited States
| | - Holly Mckee
- Lillehei Heart Institute, Department of MedicineUniversity of MinnesotaMinneapolisUnited States
| | | | - Joy Aho
- Stem Cell DepartmentBio-TechneMinneapolisUnited States
| | - Nacira Tabti
- Département de PhysiologieSorbonne Universités, Faculté de Médecine site Pitié-SalpêtrièreParisFrance
| | - Wei Shen
- Lillehei Heart Institute, Department of MedicineUniversity of MinnesotaMinneapolisUnited States
- Department of Biomedical EngineeringUniversity of MinnesotaMinneapolisUnited States
- Stem Cell InstituteUniversity of MinnesotaMinneapolisUnited States
| | - Rita CR Perlingeiro
- Lillehei Heart Institute, Department of MedicineUniversity of MinnesotaMinneapolisUnited States
- Stem Cell InstituteUniversity of MinnesotaMinneapolisUnited States
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Wang L, Geist J, Grogan A, Hu LYR, Kontrogianni-Konstantopoulos A. Thick Filament Protein Network, Functions, and Disease Association. Compr Physiol 2018; 8:631-709. [PMID: 29687901 PMCID: PMC6404781 DOI: 10.1002/cphy.c170023] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Sarcomeres consist of highly ordered arrays of thick myosin and thin actin filaments along with accessory proteins. Thick filaments occupy the center of sarcomeres where they partially overlap with thin filaments. The sliding of thick filaments past thin filaments is a highly regulated process that occurs in an ATP-dependent manner driving muscle contraction. In addition to myosin that makes up the backbone of the thick filament, four other proteins which are intimately bound to the thick filament, myosin binding protein-C, titin, myomesin, and obscurin play important structural and regulatory roles. Consistent with this, mutations in the respective genes have been associated with idiopathic and congenital forms of skeletal and cardiac myopathies. In this review, we aim to summarize our current knowledge on the molecular structure, subcellular localization, interacting partners, function, modulation via posttranslational modifications, and disease involvement of these five major proteins that comprise the thick filament of striated muscle cells. © 2018 American Physiological Society. Compr Physiol 8:631-709, 2018.
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Affiliation(s)
- Li Wang
- Department of Biochemistry and Molecular Biology, University of Maryland, Baltimore, Maryland, USA
| | - Janelle Geist
- Department of Biochemistry and Molecular Biology, University of Maryland, Baltimore, Maryland, USA
| | - Alyssa Grogan
- Department of Biochemistry and Molecular Biology, University of Maryland, Baltimore, Maryland, USA
| | - Li-Yen R. Hu
- Department of Biochemistry and Molecular Biology, University of Maryland, Baltimore, Maryland, USA
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Taglietti V, Maroli G, Cermenati S, Monteverde S, Ferrante A, Rossi G, Cossu G, Beltrame M, Messina G. Nfix Induces a Switch in Sox6 Transcriptional Activity to Regulate MyHC-I Expression in Fetal Muscle. Cell Rep 2017; 17:2354-2366. [PMID: 27880909 PMCID: PMC5149531 DOI: 10.1016/j.celrep.2016.10.082] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2015] [Revised: 09/08/2016] [Accepted: 10/24/2016] [Indexed: 02/01/2023] Open
Abstract
Sox6 belongs to the Sox gene family and plays a pivotal role in fiber type differentiation, suppressing transcription of slow-fiber-specific genes during fetal development. Here, we show that Sox6 plays opposite roles in MyHC-I regulation, acting as a positive and negative regulator of MyHC-I expression during embryonic and fetal myogenesis, respectively. During embryonic myogenesis, Sox6 positively regulates MyHC-I via transcriptional activation of Mef2C, whereas during fetal myogenesis, Sox6 requires and cooperates with the transcription factor Nfix in repressing MyHC-I expression. Mechanistically, Nfix is necessary for Sox6 binding to the MyHC-I promoter and thus for Sox6 repressive function, revealing a key role for Nfix in driving Sox6 activity. This feature is evolutionarily conserved, since the orthologs Nfixa and Sox6 contribute to repression of the slow-twitch phenotype in zebrafish embryos. These data demonstrate functional cooperation between Sox6 and Nfix in regulating MyHC-I expression during prenatal muscle development. Sox6 has opposite roles in MyHC-I regulation during embryonic and fetal myogenesis In embryonic muscle, Sox6 enhances MyHC-I expression via regulation of Mef2C In fetal muscle, Nfix is required for Sox6-mediated repression of MyHC-I The Sox6 and Nfixa orthologs cooperate in repressing smyhc1 in zebrafish
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Affiliation(s)
| | - Giovanni Maroli
- Department of Biosciences, University of Milan, Milan 20133, Italy
| | - Solei Cermenati
- Department of Biosciences, University of Milan, Milan 20133, Italy
| | | | - Andrea Ferrante
- Department of Biosciences, University of Milan, Milan 20133, Italy
| | - Giuliana Rossi
- Department of Biosciences, University of Milan, Milan 20133, Italy
| | - Giulio Cossu
- Department of Biosciences, University of Milan, Milan 20133, Italy; Division of Cell Matrix Biology and Regenerative Medicine, University of Manchester, Oxford Road, M13 9PL Manchester, UK
| | - Monica Beltrame
- Department of Biosciences, University of Milan, Milan 20133, Italy
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Rana K, Chiu MWS, Russell PK, Skinner JP, Lee NKL, Fam BC, Zajac JD, MacLean HE. Muscle-specific androgen receptor deletion shows limited actions in myoblasts but not in myofibers in different muscles in vivo. J Mol Endocrinol 2016; 57:125-38. [PMID: 27402875 DOI: 10.1530/jme-15-0320] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/22/2016] [Accepted: 07/04/2016] [Indexed: 11/08/2022]
Abstract
The aim of this study was to investigate the direct muscle cell-mediated actions of androgens by comparing two different mouse lines. The cre-loxP system was used to delete the DNA-binding activity of the androgen receptor (AR) in mature myofibers (MCK mAR(ΔZF2)) in one model and the DNA-binding activity of the AR in both proliferating myoblasts and myofibers (α-actin mAR(ΔZF2)) in another model. We found that hind-limb muscle mass was normal in MCK mAR(ΔZF2) mice and that relative mass of only some hind-limb muscles was reduced in α-actin mAR(ΔZF2) mice. This suggests that myoblasts and myofibers are not the major cellular targets mediating the anabolic actions of androgens on male muscle during growth and development. Levator ani muscle mass was decreased in both mouse lines, demonstrating that there is a myofiber-specific effect in this unique androgen-dependent muscle. We found that the pattern of expression of genes including c-myc, Fzd4 and Igf2 is associated with androgen-dependent changes in muscle mass; therefore, these genes are likely to be mediators of anabolic actions of androgens. Further research is required to identify the major targets of androgen actions in muscle, which are likely to include indirect actions via other tissues.
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Affiliation(s)
- Kesha Rana
- Department of MedicineUniversity of Melbourne, Austin Health, Heidelberg, Victoria, Australia
| | - Maria W S Chiu
- Department of MedicineUniversity of Melbourne, Austin Health, Heidelberg, Victoria, Australia
| | - Patricia K Russell
- Department of MedicineUniversity of Melbourne, Austin Health, Heidelberg, Victoria, Australia
| | - Jarrod P Skinner
- Department of MedicineUniversity of Melbourne, Austin Health, Heidelberg, Victoria, Australia
| | - Nicole K L Lee
- Department of MedicineUniversity of Melbourne, Austin Health, Heidelberg, Victoria, Australia
| | - Barbara C Fam
- Department of MedicineUniversity of Melbourne, Austin Health, Heidelberg, Victoria, Australia
| | - Jeffrey D Zajac
- Department of MedicineUniversity of Melbourne, Austin Health, Heidelberg, Victoria, Australia
| | - Helen E MacLean
- Department of MedicineUniversity of Melbourne, Austin Health, Heidelberg, Victoria, Australia
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10
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Murton AJ, Maddocks M, Stephens FB, Marimuthu K, England R, Wilcock A. Consequences of Late-Stage Non-Small-Cell Lung Cancer Cachexia on Muscle Metabolic Processes. Clin Lung Cancer 2016; 18:e1-e11. [PMID: 27461772 DOI: 10.1016/j.cllc.2016.06.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Revised: 06/07/2016] [Accepted: 06/13/2016] [Indexed: 11/25/2022]
Abstract
INTRODUCTION The loss of muscle is common in patients with advanced non-small-cell lung cancer (NSCLC) and contributes to the high morbidity and mortality of this group. The exact mechanisms behind the muscle loss are unclear. PATIENTS AND METHODS To investigate this, 4 patients with stage IV NSCLC who met the clinical definitions for sarcopenia and cachexia were recruited, along with 4 age-matched healthy volunteers. After an overnight fast, biopsy specimens were obtained from the vastus lateralis, and the key components associated with inflammation and the control of muscle protein, carbohydrate, and fat metabolism were assessed. RESULTS Compared with the healthy volunteers, significant increases in mRNA levels for interleukin-6 and NF-κB signaling and lower intramyocellular lipid content in slow-twitch fibers were observed in NSCLC patients. Although a significant decrease in phosphorylation of the mechanistic target of rapamycin (mTOR) signaling protein 4E-BP1 (Ser65) was observed, along with a trend toward reduced p70 S6K (Thr389) phosphorylation (P = .06), no difference was found between groups for the mRNA levels of MAFbx (muscle atrophy F box) and MuRF1 (muscle ring finger protein 1), chymotrypsin-like activity of the proteasome, or protein levels of multiple proteasome subunits. Moreover, despite decreases in intramyocellular lipid content, no robust changes in mRNA levels for key proteins involved in insulin signaling, glycolysis, oxidative metabolism, or fat metabolism were observed. CONCLUSION These findings suggest that examining the contribution of suppressed mTOR signaling in the loss of muscle mass in late-stage NSCLC patients is warranted and reinforces our need to understand the potential contribution of impaired fat metabolism and muscle protein synthesis in the etiology of cancer cachexia.
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Affiliation(s)
- Andrew J Murton
- Division of Nutritional Sciences, School of Biosciences, The University of Nottingham, Loughborough, United Kingdom; MRC Arthritis Research UK Centre for Musculoskeletal Ageing Research, School of Life Sciences, The University of Nottingham Medical School, Queen's Medical Centre, Nottingham, United Kingdom.
| | - Matthew Maddocks
- Department of Palliative Medicine, The University of Nottingham, Nottingham University Hospitals NHS Trust, Nottingham, United Kingdom; King's College London, Cicely Saunders Institute, London, United Kingdom
| | - Francis B Stephens
- MRC Arthritis Research UK Centre for Musculoskeletal Ageing Research, School of Life Sciences, The University of Nottingham Medical School, Queen's Medical Centre, Nottingham, United Kingdom
| | - Kanagaraj Marimuthu
- MRC Arthritis Research UK Centre for Musculoskeletal Ageing Research, School of Life Sciences, The University of Nottingham Medical School, Queen's Medical Centre, Nottingham, United Kingdom
| | - Ruth England
- Department of Palliative Medicine, The University of Nottingham, Nottingham University Hospitals NHS Trust, Nottingham, United Kingdom
| | - Andrew Wilcock
- Department of Palliative Medicine, The University of Nottingham, Nottingham University Hospitals NHS Trust, Nottingham, United Kingdom
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Walklate J, Vera C, Bloemink MJ, Geeves MA, Leinwand L. The Most Prevalent Freeman-Sheldon Syndrome Mutations in the Embryonic Myosin Motor Share Functional Defects. J Biol Chem 2016; 291:10318-31. [PMID: 26945064 PMCID: PMC4858979 DOI: 10.1074/jbc.m115.707489] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Indexed: 11/12/2022] Open
Abstract
The embryonic myosin isoform is expressed during fetal development and rapidly down-regulated after birth. Freeman-Sheldon syndrome (FSS) is a disease associated with missense mutations in the motor domain of this myosin. It is the most severe form of distal arthrogryposis, leading to overcontraction of the hands, feet, and orofacial muscles and other joints of the body. Availability of human embryonic muscle tissue has been a limiting factor in investigating the properties of this isoform and its mutations. Using a recombinant expression system, we have studied homogeneous samples of human motors for the WT and three of the most common FSS mutants: R672H, R672C, and T178I. Our data suggest that the WT embryonic myosin motor is similar in contractile speed to the slow type I/β cardiac based on the rate constant for ADP release and ADP affinity for actin-myosin. All three FSS mutations show dramatic changes in kinetic properties, most notably the slowing of the apparent ATP hydrolysis step (reduced 5–9-fold), leading to a longer lived detached state and a slowed Vmax of the ATPase (2–35-fold), indicating a slower cycling time. These mutations therefore seriously disrupt myosin function.
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Affiliation(s)
- Jonathan Walklate
- From the School of Biosciences, University of Kent, Canterbury CT2 7NJ, United Kingdom and
| | - Carlos Vera
- the Department of Molecular and Developmental Biology, University of Colorado, Boulder, Colorado 80309
| | - Marieke J Bloemink
- From the School of Biosciences, University of Kent, Canterbury CT2 7NJ, United Kingdom and
| | - Michael A Geeves
- From the School of Biosciences, University of Kent, Canterbury CT2 7NJ, United Kingdom and
| | - Leslie Leinwand
- the Department of Molecular and Developmental Biology, University of Colorado, Boulder, Colorado 80309
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Schiaffino S, Rossi AC, Smerdu V, Leinwand LA, Reggiani C. Developmental myosins: expression patterns and functional significance. Skelet Muscle 2015; 5:22. [PMID: 26180627 PMCID: PMC4502549 DOI: 10.1186/s13395-015-0046-6] [Citation(s) in RCA: 308] [Impact Index Per Article: 34.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2015] [Accepted: 05/27/2015] [Indexed: 11/24/2022] Open
Abstract
Developing skeletal muscles express unique myosin isoforms, including embryonic and neonatal myosin heavy chains, coded by the myosin heavy chain 3 (MYH3) and MYH8 genes, respectively, and myosin light chain 1 embryonic/atrial, encoded by the myosin light chain 4 (MYL4) gene. These myosin isoforms are transiently expressed during embryonic and fetal development and disappear shortly after birth when adult fast and slow myosins become prevalent. However, developmental myosins persist throughout adult stages in specialized muscles, such as the extraocular and jaw-closing muscles, and in the intrafusal fibers of the muscle spindles. These myosins are re-expressed during muscle regeneration and provide a specific marker of regenerating fibers in the pathologic skeletal muscle. Mutations in MYH3 or MYH8 are responsible for distal arthrogryposis syndromes, characterized by congenital joint contractures and orofacial dysmorphisms, supporting the importance of muscle contractile activity and body movements in joint development and in shaping the form of the face during fetal development. The biochemical and biophysical properties of developmental myosins have only partially been defined, and their functional significance is not yet clear. One possibility is that these myosins are specialized in contracting against low loads, and thus, they may be adapted to the prenatal environment, when fetal muscles contract against a very low load compared to postnatal muscles.
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Affiliation(s)
- Stefano Schiaffino
- Venetian Institute of Molecular Medicine (VIMM), Via G. Orus 2, 35129 Padova, Italy
| | - Alberto C Rossi
- Department of Molecular, Cellular and Developmental Biology and BioFrontiers Institute, University of Colorado, Boulder, CO USA
| | - Vika Smerdu
- Institute of Anatomy, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Leslie A Leinwand
- Department of Molecular, Cellular and Developmental Biology and BioFrontiers Institute, University of Colorado, Boulder, CO USA
| | - Carlo Reggiani
- Department of Biomedical Sciences, University of Padova, Padova, Italy ; CNR Institute of Neuroscience, Padova, Italy
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13
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Pilichi S, Rocca S, Pool RR, Dattena M, Masala G, Mara L, Sanna D, Casu S, Manunta ML, Manunta A, Passino ES. Treatment with embryonic stem-like cells into osteochondral defects in sheep femoral condyles. BMC Vet Res 2014; 10:301. [PMID: 25523522 PMCID: PMC4297431 DOI: 10.1186/s12917-014-0301-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2014] [Accepted: 12/11/2014] [Indexed: 02/06/2023] Open
Abstract
Background Articular cartilage has poor intrinsic capacity for regeneration because of its avascularity and very slow cellular turnover. Defects deriving from trauma or joint disease tend to be repaired with fibrocartilage rather than hyaline cartilage. Consequent degenerative processes are related to the width and depth of the defect. Since mesenchymal stem cells (MSCs) deriving from patients affected by osteoarthritis have a lower proliferative and chondrogenic activity, the systemic or local delivery of heterologous cells may enhance regeneration or inhibit the progressive loss of joint tissue. Embryonic stem cells (ESCs) are very promising, since they can self-renew for prolonged periods without differentiation and can differentiate into tissues from all the 3 germ layers. To date only a few experiments have used ESCs for the study of the cartilage regeneration in animal models and most of them used laboratory animals. Sheep, due to their anatomical, physiological and immunological similarity to humans, represent a valid model for translational studies. This experiment aimed to evaluate if the local delivery of male sheep embryonic stem-like (ES-like) cells into osteochondral defects in the femoral condyles of adult sheep can enhance the regeneration of articular cartilage. Twenty-two ewes were divided into 5 groups (1, 2, 6, 12 and 24 months after surgery). Newly formed tissue was evaluated by macroscopic, histological, immunohistochemical (collagen type II) and fluorescent in situ hybridization (FISH) assays. Results Regenerated tissue was ultimately evaluated on 17 sheep. Samples engrafted with ES-like cells had significantly better histologic evidence of regeneration with respect to empty defects, used as controls, at all time periods. Conclusions Histological assessments demonstrated that the local delivery of ES-like cells into osteochondral defects in sheep femoral condyles enhances the regeneration of the articular hyaline cartilage, without signs of immune rejection or teratoma for 24 months after engraftment. Electronic supplementary material The online version of this article (doi:10.1186/s12917-014-0301-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Susanna Pilichi
- Department of Animal Science, Agricultural Research Agency of Sardinia, Olmedo, Sassari, 07040, Italy.
| | - Stefano Rocca
- Department of Veterinary Medicine, via Vienna, Sassari, 07100, Italy.
| | - Roy R Pool
- Department of Veterinary Pathobiology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, 77843-4467, TX, USA.
| | - Maria Dattena
- Department of Animal Science, Agricultural Research Agency of Sardinia, Olmedo, Sassari, 07040, Italy.
| | - Gerolamo Masala
- Department of Veterinary Medicine, via Vienna, Sassari, 07100, Italy.
| | - Laura Mara
- Department of Animal Science, Agricultural Research Agency of Sardinia, Olmedo, Sassari, 07040, Italy.
| | - Daniela Sanna
- Department of Animal Science, Agricultural Research Agency of Sardinia, Olmedo, Sassari, 07040, Italy.
| | - Sara Casu
- Department of Animal Science, Agricultural Research Agency of Sardinia, Olmedo, Sassari, 07040, Italy.
| | - Maria L Manunta
- Department of Veterinary Medicine, via Vienna, Sassari, 07100, Italy.
| | - Andrea Manunta
- Department of Surgery, Microsurgery and Medicine, University of Sassari, viale San Pietro, Sassari, 07100, Italy.
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Kim HH, Kim JG, Jeong J, Han SY, Kim KW. Akap12 is essential for the morphogenesis of muscles involved in zebrafish locomotion. Differentiation 2014; 88:106-16. [PMID: 25534553 DOI: 10.1016/j.diff.2014.11.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2014] [Revised: 10/20/2014] [Accepted: 11/28/2014] [Indexed: 12/22/2022]
Abstract
Swimming behavior in fish is driven by coordinated contractions of muscle fibers. In zebrafish, slow muscle cell migration is crucial for the formation of the muscle network; slow myoblasts, which arise from medial adaxial cells, migrate radially to the lateral surface of the trunk and tail during embryogenesis. This study found that the zebrafish A-kinase anchoring protein (akap)12 isoforms akap12α and akap12β are required for muscle morphogenesis and locomotor activity. Embryos deficient in akap12 exhibited reduced spontaneous coiling, touch response, and free swimming. Akap12-depleted slow but not fast muscle cells were misaligned, suggesting that the behavioral abnormalities resulted from specific defects in slow muscle patterning; indeed, slow muscle cells and muscle pioneers in these embryos showed abnormal migration in a cell-autonomous manner. Taken together, these results suggest that akap12 plays a critical role in the development of zebrafish locomotion by regulating the normal morphogenesis of muscles.
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Affiliation(s)
- Hyun-Ho Kim
- SNU-Harvard NeuroVascular Protection Research Center, College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul 151-742, Korea
| | - Jeong-gyun Kim
- Department of Molecular Medicine and Biopharmaceutical Science, Graduate School of Convergence Science and Technology, Seoul National University, Seoul 151-742, Korea
| | - Jinkyung Jeong
- SNU-Harvard NeuroVascular Protection Research Center, College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul 151-742, Korea
| | - Song-Yi Han
- Department of Molecular Medicine and Biopharmaceutical Science, Graduate School of Convergence Science and Technology, Seoul National University, Seoul 151-742, Korea
| | - Kyu-Won Kim
- SNU-Harvard NeuroVascular Protection Research Center, College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul 151-742, Korea; Department of Molecular Medicine and Biopharmaceutical Science, Graduate School of Convergence Science and Technology, Seoul National University, Seoul 151-742, Korea.
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15
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Ojima K, Oe M, Nakajima I, Shibata M, Chikuni K, Muroya S, Nishimura T. Proteomic analysis of secreted proteins from skeletal muscle cells during differentiation. EUPA OPEN PROTEOMICS 2014. [DOI: 10.1016/j.euprot.2014.08.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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16
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Luo Q, Douglas M, Burkholder T, Sokoloff AJ. Absence of developmental and unconventional myosin heavy chain in human suprahyoid muscles. Muscle Nerve 2014; 49:534-44. [PMID: 23835800 DOI: 10.1002/mus.23946] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2012] [Revised: 06/25/2013] [Accepted: 06/27/2013] [Indexed: 11/07/2022]
Abstract
INTRODUCTION Contradictory reports of the myosin heavy chain (MHC) composition of adult human suprahyoid muscles leave unresolved the extent to which these muscles express developmental and unconventional MHC. METHODS By immunohistochemistry, separation sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE)-Coomassie, separation SDS-PAGE-Western blot, and mRNA PCR, we tested for conventional MHCI, MHCIIA, MHCIIX, developmental MHC embryonic and MHC neonatal, and unconventional MHC alpha-cardiac, MHC extraocular, and MHC slow tonic in adult human anterior digastric (AD), geniohyoid (GH), and mylohyoid (MH) muscles. RESULTS By separation SDS-PAGE-Coomassie and Western blot, only conventional MHC are present. By immunohistochemistry all muscle fibers are positive for MHCI, MHCIIA, or MHCIIX, and fewer than 4 fibers/mm(2) are positive for developmental or unconventional MHC. By PCR, mRNA of MHCI and MHCIIA dominate, with sporadically detectable MHC alpha-cardiac and without detectable mRNA of other developmental and unconventional MHC. CONCLUSIONS We conclude that human suprahyoid muscles AD, GH, and MH are composed almost exclusively of conventional MHC isoforms.
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Affiliation(s)
- Qingwei Luo
- Department of Physiology, Emory University, 615 Michael Street, Atlanta, Georgia, 30322, USA
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17
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Adams GR, Bamman MM. Characterization and regulation of mechanical loading-induced compensatory muscle hypertrophy. Compr Physiol 2013; 2:2829-70. [PMID: 23720267 DOI: 10.1002/cphy.c110066] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
In mammalian systems, skeletal muscle exists in a dynamic state that monitors and regulates the physiological investment in muscle size to meet the current level of functional demand. This review attempts to consolidate current knowledge concerning development of the compensatory hypertrophy that occurs in response to a sustained increase in the mechanical loading of skeletal muscle. Topics covered include: defining and measuring compensatory hypertrophy, experimental models, loading stimulus parameters, acute responses to increased loading, hyperplasia, myofiber-type adaptations, the involvement of satellite cells, mRNA translational control, mechanotransduction, and endocrinology. The authors conclude with their impressions of current knowledge gaps in the field that are ripe for future study.
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Affiliation(s)
- Gregory R Adams
- Department of Physiology and Biophysics, University of California Irvine, Irvine, California, USA.
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18
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Stuart CA, McCurry MP, Marino A, South MA, Howell MEA, Layne AS, Ramsey MW, Stone MH. Slow-twitch fiber proportion in skeletal muscle correlates with insulin responsiveness. J Clin Endocrinol Metab 2013; 98:2027-36. [PMID: 23515448 PMCID: PMC3644602 DOI: 10.1210/jc.2012-3876] [Citation(s) in RCA: 141] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
CONTEXT The metabolic syndrome, characterized by central obesity with dyslipidemia, hypertension, and hyperglycemia, identifies people at high risk for type 2 diabetes. OBJECTIVE Our objective was to determine how the insulin resistance of the metabolic syndrome is related to muscle fiber composition. DESIGN Thirty-nine sedentary men and women (including 22 with the metabolic syndrome) had insulin responsiveness quantified using euglycemic clamps and underwent biopsies of the vastus lateralis muscle. Expression of insulin receptors, insulin receptor substrate-1, glucose transporter 4, and ATP synthase were quantified with immunoblots and immunohistochemistry. PARTICIPANTS AND SETTING Participants were nondiabetic, metabolic syndrome volunteers and sedentary control subjects studied at an outpatient clinic. MAIN OUTCOME MEASURES Insulin responsiveness during an insulin clamp and the fiber composition of a muscle biopsy specimen were evaluated. RESULTS There were fewer type I fibers and more mixed (type IIa) fibers in metabolic syndrome subjects. Insulin responsiveness and maximal oxygen uptake correlated with the proportion of type I fibers. Insulin receptor, insulin receptor substrate-1, and glucose transporter 4 expression were not different in whole muscle but all were significantly less in the type I fibers of metabolic syndrome subjects when adjusted for fiber proportion and fiber size. Fat oxidation and muscle mitochondrial expression were not different in the metabolic syndrome subjects. CONCLUSION Lower proportion of type I fibers in metabolic syndrome muscle correlated with the severity of insulin resistance. Even though whole muscle content was normal, key elements of insulin action were consistently less in type I muscle fibers, suggesting their distribution was important in mediating insulin effects.
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MESH Headings
- ATP Synthetase Complexes/metabolism
- Adult
- Antigens, CD/metabolism
- Body Mass Index
- Diabetes Mellitus, Type 2/epidemiology
- Diabetes Mellitus, Type 2/etiology
- Female
- Glucose Transporter Type 4/metabolism
- Humans
- Insulin Receptor Substrate Proteins/metabolism
- Insulin Resistance
- Male
- Metabolic Syndrome/complications
- Metabolic Syndrome/metabolism
- Metabolic Syndrome/pathology
- Middle Aged
- Muscle Fibers, Fast-Twitch/enzymology
- Muscle Fibers, Fast-Twitch/metabolism
- Muscle Fibers, Fast-Twitch/pathology
- Muscle Fibers, Slow-Twitch/enzymology
- Muscle Fibers, Slow-Twitch/metabolism
- Muscle Fibers, Slow-Twitch/pathology
- Obesity/complications
- Quadriceps Muscle/enzymology
- Quadriceps Muscle/metabolism
- Quadriceps Muscle/pathology
- Receptor, Insulin/metabolism
- Risk
- Sedentary Behavior
- Tennessee/epidemiology
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Affiliation(s)
- Charles A Stuart
- Department of Internal Medicine, Quillen College of Medicine, East Tennessee State University, P.O. Box 70622, Johnson City, Tennessee 37614-0622, USA.
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Intrafusal myosin heavy chain expression of human masseter and biceps muscles at young age shows fundamental similarities but also marked differences. Histochem Cell Biol 2013; 139:895-907. [PMID: 23306907 DOI: 10.1007/s00418-012-1072-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/15/2012] [Indexed: 10/27/2022]
Abstract
Muscle spindles are skeletal muscle mechanoreceptors that provide proprioceptive information to the central nervous system. The human adult masseter muscle has greater number, larger and more complex muscle spindles than the adult biceps. For a better knowledge of muscle diversity and physiological properties, this study examined the myosin heavy chain (MyHC) expression of muscle spindle intrafusal fibres in the human young masseter and young biceps muscles by using a panel of monoclonal antibodies (mAbs) against different MyHC isoforms. Eight MyHC isoforms were detected in both muscles-slow-tonic, I, IIa, IIx, foetal, embryonic, α-cardiac and an isoform not previously reported in intrafusal fibres, termed IIx'. Individual fibres co-expressed 2-6 isoforms. MyHC-slow tonic separated bag1, AS-bag1 and bag2 fibres from chain fibres. Typically, bag fibres also expressed MyHC-I and α-cardiac, whereas chain fibres expressed IIa and foetal. In the young masseter 98 % of bag1 showed MyHC-α cardiac versus 30 % in the young biceps, 35 % of bag2 showed MyHC-IIx' versus none in biceps, 17 % of the chain fibres showed MyHC-I versus 61 % in the biceps. In conclusion, the result showed fundamental similarities in intrafusal MyHC expression between young masseter and biceps, but also marked differences implying muscle-specific proprioceptive control, probably related to diverse evolutionary and developmental origins. Finding of similarities in MyHC expression between young and adult masseter and biceps muscle spindles, respectively, in accordance with previously reported similarities in mATPase fibre type composition suggest early maturation of muscle spindles, preceding extrafusal fibres in growth and maturation.
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20
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Maltin CA. Muscle development and obesity: Is there a relationship? Organogenesis 2012; 4:158-69. [PMID: 19279728 DOI: 10.4161/org.4.3.6312] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2008] [Accepted: 05/20/2008] [Indexed: 12/25/2022] Open
Abstract
The formation of skeletal muscle from the epithelial somites involves a series of events triggered by temporally and spatially discrete signals resulting in the generation of muscle fibers which vary in their contractile and metabolic nature. The fiber type composition of muscles varies between individuals and it has now been found that there are differences in fiber type proportions between lean and obese animals and humans. Amongst the possible causes of obesity, it has been suggested that inappropriate prenatal environments may 'program' the fetus and may lead to increased risks for disease in adult life. The characteristics of muscle are both heritable and plastic, giving the tissue some ability to adapt to signals and stimuli both pre and postnatally. Given that muscle is a site of fatty acid oxidation and carbohydrate metabolism and that its development can be changed by prenatal events, it is interesting to examine the possible relationship between muscle development and the risk of obesity.
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Affiliation(s)
- Charlotte A Maltin
- School of Pharmacy and Life Sciences; Robert Gordon University; Aberdeen UK
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21
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Remarkable heterogeneity in myosin heavy-chain composition of the human young masseter compared with young biceps brachii. Histochem Cell Biol 2012; 138:669-82. [PMID: 22777345 DOI: 10.1007/s00418-012-0985-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/26/2012] [Indexed: 10/28/2022]
Abstract
Adult human jaw muscles differ from limb and trunk muscles in enzyme-histochemical fibre type composition. Recently, we showed that the human masseter and biceps differ in fibre type pattern already at childhood. The present study explored the myosin heavy-chain (MyHC) expression in the young masseter and biceps muscles by means of gel electrophoresis (GE) and immuno-histochemical (IHC) techniques. Plasticity in MyHC expression during life was evaluated by comparing the results with the previously reported data for adult muscles. In young masseter, GE identified MyHC-I, MyHC-IIa MyHC-IIx and small proportions of MyHC-fetal and MyHC-α cardiac. Western blots confirmed the presence of MyHC-I, MyHC-IIa and MyHC-IIx. IHC revealed in the masseter six isomyosins, MyHC-I, MyHC-IIa, MyHC-IIx, MyHC-fetal, MyHC α-cardiac and a previously not reported isoform, termed MyHC-IIx'. The majority of the masseter fibres co-expressed two to four isoforms. In the young biceps, both GE and IHC identified MyHC-I, MyHC-IIa and MyHC-IIx. MyHC-I predominated in both muscles. Young masseter showed more slow and less-fast and fetal MyHC than the adult and elderly masseter. These results provide evidence that the young masseter muscle is unique in MyHC composition, expressing MyHC-α cardiac and MyHC-fetal isoforms as well as hitherto unrecognized potential spliced isoforms of MyHC-fetal and MyHC-IIx. Differences in masseter MyHC expression between young adult and elderly suggest a shift from childhood to adulthood towards more fast contractile properties. Differences between masseter and biceps are proposed to reflect diverse evolutionary and developmental origins and confirm that the masseter and biceps present separate allotypes of muscle.
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22
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Stål PS, Johansson B. Abnormal Mitochondria Organization and Oxidative Activity in the Palate Muscles of Long-Term Snorers with Obstructive Sleep Apnea. Respiration 2012; 83:407-17. [DOI: 10.1159/000336040] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2010] [Accepted: 11/17/2011] [Indexed: 11/19/2022] Open
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Osterlund C, Thornell LE, Eriksson PO. Differences in fibre type composition between human masseter and biceps muscles in young and adults reveal unique masseter fibre type growth pattern. Anat Rec (Hoboken) 2011; 294:1158-69. [PMID: 21634018 DOI: 10.1002/ar.21272] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2009] [Accepted: 08/10/2010] [Indexed: 11/08/2022]
Abstract
The human jaw system is different from those of other primates, carnivores, ruminants, and rodents in temporomandibular joint and muscle anatomy. In adults, jaw muscles also differ markedly from limb and trunk muscles in composition and distribution of fibre types. It can be assumed that age-related changes between young age to adulthood in terms of craniofacial growth, teeth eruption, and improvement of jaw functions are paralleled by alterations also in composition and distribution of jaw muscle fibre types. To address this question, we have examined the fibre type composition of the human masseter, a jaw closing muscle, at young age. For comparison, the young biceps brachii was examined. The results were compared with previous data for adult masseter and biceps muscles. Young masseter and biceps were similar in that type I fibres outnumbered other fibre types and were of the same diameter. However, they differed in composition of other fibre types. Young masseter contained fibre types I, IM, IIC, IIAB, IIB, and scarce IIA, with regional differences, whereas young biceps showed types I, IIA, IIAB, and few IIB. Young masseter differed from young biceps also by smaller type II fibre diameter and by containing fetal MyHC. In addition, the masseter and biceps differed in age-related changes of composition and distribution of fibre types between young age and adulthood. We conclude that the human masseter is specialized in fibre types already at young age and shows a unique fibre type growth pattern, in concordance with being a separate allotype of muscle.
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Timmers S, de Vogel-van den Bosch J, Towler MC, Schaart G, Moonen-Kornips E, Mensink RP, Hesselink MK, Hardie DG, Schrauwen P. Prevention of high-fat diet-induced muscular lipid accumulation in rats by alpha lipoic acid is not mediated by AMPK activation. J Lipid Res 2009; 51:352-9. [PMID: 19690335 DOI: 10.1194/jlr.m000992] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Skeletal muscle triglyceride accumulation is associated with insulin resistance in obesity. Recently, it has been suggested that alpha lipoic acid (ALA) improves insulin sensitivity by lowering triglyceride accumulation in nonadipose tissues via activation of skeletal muscle AMP-activated protein kinase (AMPK). We examined whether chronic ALA supplementation prevents muscular lipid accumulation that is associated with high-fat diets via activation of AMPK. In addition, we tested if ALA supplementation was able to improve insulin sensitivity in rats fed low- and high-fat diets (LFD, HFD). Supplementing male Wistar rats with 0.5% ALA for 8 weeks significantly reduced body weight, both on LFD and HFD (-24% LFD+ALA vs. LFD, P < 0.01, and -29% HFD+ALA vs. HFD, P < 0.001). Oil red O lipid staining revealed a 3-fold higher lipid content in skeletal muscle after HFD compared with LFD and ALA-supplemented groups (P < 0.05). ALA improved whole body glucose tolerance ( approximately 20% lower total area under the curve (AUC) in ALA supplemented groups vs. controls, P < 0.05). These effects were not mediated by increased muscular AMPK activation or ALA-induced improvement of muscular insulin sensitivity. To conclude, the prevention of HFD-induced muscular lipid accumulation and the improved whole body glucose tolerance are likely secondary effects due to the anorexic nature of ALA.
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Affiliation(s)
- Silvie Timmers
- Top Institute Food and Nutrition (TIFN), 6700 AN, Wageningen, The Netherlands
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25
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Dattena M, Pilichi S, Rocca S, Mara L, Casu S, Masala G, Manunta L, Manunta A, Passino ES, Pool RR, Cappai P. Sheep embryonic stem-like cells transplanted in full-thickness cartilage defects. J Tissue Eng Regen Med 2009; 3:175-87. [PMID: 19226519 DOI: 10.1002/term.151] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Articular cartilage regeneration is limited. Embryonic stem (ES) cell lines provide a source of totipotent cells for regenerating cartilage. Anatomical, biomechanical, physiological and immunological similarities between humans and sheep make this animal an optimal experimental model. This study examines the repair process of articular cartilage in sheep after transplantation of ES-like cells isolated from inner cell masses (ICMs) derived from in vitro-produced (IVP) vitrified embryos. Thirty-five ES-like colonies from 40 IVP embryos, positive for stage-specific embryonic antigens (SSEAs), were pooled in groups of two or three, embedded in fibrin glue and transplanted into osteochondral defects in the medial femoral condyles of 14 ewes. Empty defect (ED) and cell-free glue (G) in the controlateral stifle joint served as controls. The Y gene sequence was used to detect ES-like cells in the repair tissue by in situ hybridization (ISH). Two ewes were euthanized at 1 month post-operatively, three each at 2 and 6 months and four at 12 months. Repairing tissue was examined by biomechanical, macroscopic, histological, immunohistochemical (collagen type II) and ISH assays. Scores of all treatments showed no statistical significant differences among treatment groups at a given time period, although ES-like grafts showed a tendency toward a better healing process. ISH was positive in all ES-like specimens. This study demonstrates that ES-like cells transplanted into cartilage defects stimulate the repair process to promote better organization and tissue bulk. However, the small number of cells applied and the short interval between surgery and euthanasia might have negatively affected the results.
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Affiliation(s)
- Maria Dattena
- AGRIS Sardegna, Laboratory of Biotechnology of Animal Reproduction, Department of Research in Animal Production, Sassari, Italy.
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Maggs AM, Huxley C, Hughes SM. Nerve-dependent changes in skeletal muscle myosin heavy chain after experimental denervation and cross-reinnervation and in a demyelinating mouse model of Charcot-Marie-Tooth disease type 1A. Muscle Nerve 2009; 38:1572-84. [PMID: 19016545 DOI: 10.1002/mus.21106] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Innervation regulates the contractile properties of vertebrate muscle fibers, in part through the effect of electrical activity on expression of distinct myosins. Herein we analyze the role of innervation in regulating the accumulation of the general, maturational, and adult forms of rodent slow myosin heavy chain (MyHC) that are defined by the presence of distinct antigenic epitopes. Denervation increases the number of fibers that express general slow MyHC, but it decreases the adult slow MyHC epitope. Cross-reinnervation of slow muscle by a fast nerve leads to an increase in the number of fibers that express fast MyHC. In both cases, there is an increase in the number of fibers that express slow and fast IIA MyHCs, but without the adult slow MyHC epitope. The data suggest that innervation is required for maturation and maintenance of diversity of both slow and fast fibers. The sequence of slow MyHC epitope transitions is a useful biomarker, and it may play a significant role during nerve-dependent changes in muscle fiber function. We applied this detailed muscle analysis to a transgenic mouse model of human motor and sensory neuropathy IA, also known as Charcot-Marie-Tooth disease type 1A (CMT1A), in which electrical conduction in some motor nerves is poor due to demyelination. The mice display atrophy of some muscle fibers and changes in slow and fast MyHC epitope expression, suggestive of a progressive increase in innervation of muscle fibers by fast motor neurons, even at early stages. The potential role of these early changes in disease pathogenesis is assessed.
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Affiliation(s)
- Alison M Maggs
- Randall Division for Cell Biophysics, King's College London, UK
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Dalrymple K, Shuler C, Prigozy T. Embryonic, fetal, and neonatal tongue myoblasts exhibit molecular heterogeneity in vitro. Differentiation 2008. [DOI: 10.1111/j.1432-0436.2000.660408.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Matsuoka Y, Inoue A. Controlled differentiation of myoblast cells into fast and slow muscle fibers. Cell Tissue Res 2008; 332:123-32. [DOI: 10.1007/s00441-008-0582-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2007] [Accepted: 01/14/2008] [Indexed: 10/22/2022]
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Jocken JWE, Smit E, Goossens GH, Essers YPG, van Baak MA, Mensink M, Saris WHM, Blaak EE. Adipose triglyceride lipase (ATGL) expression in human skeletal muscle is type I (oxidative) fiber specific. Histochem Cell Biol 2008; 129:535-8. [PMID: 18224330 PMCID: PMC2668625 DOI: 10.1007/s00418-008-0386-y] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/11/2008] [Indexed: 12/17/2022]
Abstract
Accumulation of triacylglycerol (TAG) and lipid intermediates in skeletal muscle plays an important role in the etiology of insulin resistance and type 2 diabetes mellitus. Disturbances in skeletal muscle lipid turnover and lipolysis may contribute significantly to this. So far, knowledge on the regulation of muscle lipolysis is limited. Recently the identification of a new lipase was reported: adipose triglyceride lipase (ATGL). ATGL deficient animals show significant lipid accumulation in skeletal muscle, which may indicate that ATGL plays a pivotal role in skeletal muscle lipolysis. However, until now, it is still unknown whether ATGL protein is expressed in human skeletal muscle. Therefore, the aim of the present study was to investigate whether ATGL is expressed at the protein level in human skeletal muscle, and to examine whether its expression is fiber-type specific. To accomplish this, we established an imunohistochemical and immunofluorescent staining procedure to study ATGL protein expression in relation to fiber type in human vastus lateralis muscle of eight male subjects (BMI range: 21.0–34.5 kg/m2 and age: 38–59 years). In the present paper we report for the first time that ATGL protein is indeed expressed in human skeletal muscle. Moreover, ATGL is exclusively expressed in type I (oxidative) muscle fibers, suggesting a pivotal role for ATGL in intramuscular fatty acid handling, lipid storage and breakdown.
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Affiliation(s)
- Johan W E Jocken
- Department of Human Biology, Nutrition and Toxicology Research Institute Maastricht, Maastricht University, PO Box 616, 6200 MD Maastricht, The Netherlands.
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McConell GK, Bradley SJ, Stephens TJ, Canny BJ, Kingwell BA, Lee-Young RS. Skeletal muscle nNOSμ protein content is increased by exercise training in humans. Am J Physiol Regul Integr Comp Physiol 2007; 293:R821-8. [PMID: 17459909 DOI: 10.1152/ajpregu.00796.2006] [Citation(s) in RCA: 97] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
The major isoform of nitric oxide synthase (NOS) in skeletal muscle is the splice variant of neuronal NOS, termed nNOSμ. Exercise training increases nNOSμ protein levels in rat skeletal muscle, but data in humans are conflicting. We performed two studies to determine 1) whether resting nNOSμ protein expression is greater in skeletal muscle of 10 endurance-trained athletes compared with 11 sedentary individuals ( study 1) and 2) whether intense short-term (10 days) exercise training increases resting nNOSμ protein (within whole muscle and also within types I, IIa, and IIx fibers) in eight sedentary individuals ( study 2). In study 1, nNOSμ protein was ∼60% higher ( P < 0.05) in endurance-trained athletes compared with the sedentary participants. In study 2, nNOSμ protein expression was similar in types I, IIa, and IIx fibers before training. Ten days of intense exercise training significantly ( P < 0.05) increased nNOSμ protein levels in types I, IIa, and IIx fibers, a finding that was validated by using whole muscle samples. Endothelial NOS and inducible NOS protein were barely detectable in the skeletal muscle samples. In conclusion, nNOSμ protein expression is greater in endurance-trained individuals when compared with sedentary individuals. Ten days of intense exercise is also sufficient to increase nNOSμ expression in untrained individuals, due to uniform increases of nNOSμ within types I, IIa, and IIx fibers.
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Affiliation(s)
- Glenn K McConell
- Department of Physiology, The University of Melbourne, Parkville, Victoria 3010, Australia.
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Mackey AL, Esmarck B, Kadi F, Koskinen SOA, Kongsgaard M, Sylvestersen A, Hansen JJ, Larsen G, Kjaer M. Enhanced satellite cell proliferation with resistance training in elderly men and women. Scand J Med Sci Sports 2007; 17:34-42. [PMID: 17305939 DOI: 10.1111/j.1600-0838.2006.00534.x] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
In addition to the well-documented loss of muscle mass and strength associated with aging, there is evidence for the attenuating effects of aging on the number of satellite cells in human skeletal muscle. The aim of this study was to investigate the response of satellite cells in elderly men and women to 12 weeks of resistance training. Biopsies were collected from the m. vastus lateralis of 13 healthy elderly men and 16 healthy elderly women (mean age 76+/-SD 3 years) before and after the training period. Satellite cells were visualized by immunohistochemical staining of muscle cross-sections with a monoclonal antibody against neural cell adhesion molecule (NCAM) and counterstaining with Mayer's hematoxylin. Compared with the pre-training values, there was a significant increase (P<0.05) in the number of NCAM-positively stained cells per fiber post-training in males (from 0.11+/-0.03 to 0.15+/-0.06; mean+/-SD) and females (from 0.11+/-0.04 to 0.13+/-0.05). These results suggest that 12 weeks of resistance training is effective in enhancing the satellite cell pool in skeletal muscle in the elderly.
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Affiliation(s)
- A L Mackey
- Institute of Sports Medicine, Bispebjerg Hospital, Copenhagen, Denmark.
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32
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Wicke W, Wasicky R, Brugger PC, Kaminski S, Lukas JR. Histochemical and immunohistochemical study on muscle fibers in human extraocular muscle spindles. Exp Eye Res 2007; 84:670-9. [PMID: 17270173 DOI: 10.1016/j.exer.2006.12.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2006] [Revised: 11/10/2006] [Accepted: 12/04/2006] [Indexed: 11/28/2022]
Abstract
Human extraocular muscles are unique in several ways including their endowment with proprioceptive organs. Aim of this study was to establish a classification of intrafusal muscle fibers of human extraocular muscles based on their histochemical and immunohistochemical properties and to determine their relationship to extrafusal extraocular muscle fiber types in this respect. Using light microscopy, intrafusal muscle fibers were followed on consecutive cross-sections and classified according to the localization of their myonuclei and to their enzyme- and myosin-immunohistochemical characteristics. Sixteen muscle spindles in human extraocular muscles counted as 'true' spindles revealed 27% nuclear chain fibers [40.1 microm+/-10.4; perimeter+/-SD] and 73% anomalous fibers [44.1 microm+/-12]. Seven 'false' muscle spindles showed only anomalous fibers [43.8 microm+/-11.1] and entirely lacked nuclear chain fibers. Six fiber types were distinguished according to their histochemical and myosin heavy chain immunohistochemical properties. Fiber type 1 [46.3 microm+/-13.3] was made up of fast-twitch myosin heavy chain isoform. Fiber type 2 [39.5 microm+/-10] additionally expressed a developmental myosin heavy chain isoform. Fiber type 3 [42.8 microm+/-10.4] consisted of pure slow-twitch positive muscle fibers. Slow-twitch MHC and fast-twitch myosin heavy chain isoform were found in fiber type 4 [43.3 microm+/-9]. Fiber types 5 and 6 showed different myosin heavy chain patterns than fiber types 1-4. The vast majority of nuclear chain fibers displayed fiber type 2 features, but 12% of nuclear chain fibers were found to be of fiber type 1. Among anomalous fibers in true spindles the frequency of fiber type 1 was much higher than in false spindles. On the other hand, fiber type 4 was found more often in false than in true spindles. With regard to their histochemical and immunohistochemical properties intrafusal muscle fibers in human extraocular muscles differ both from intrafusal muscle fibers in other skeletal muscles and from extrafusal muscle fibers in extraocular eye muscles. These conspicuous differences to skeletal muscle spindles relate to their morphology and myosin heavy chain characteristics. In particular, the occurrence of anomalous fibers might reflect dynamic neuronal processes and might be necessary for modulating and adapting processes in advancing age, as well as maintaining proprioceptive input during the whole life.
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Affiliation(s)
- Waltraut Wicke
- Medical University of Vienna, Center of Anatomy and Cell Biology, Integrative Morphology Group, Waehringer Stasse 13, 1090 Vienna, and Institute of Pathology and Bacteriology, Kaiserin Elisabeth Hospital, Austria.
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Mensink M, Hesselink MKC, Russell AP, Schaart G, Sels JP, Schrauwen P. Improved skeletal muscle oxidative enzyme activity and restoration of PGC-1α and PPARβ/δ gene expression upon rosiglitazone treatment in obese patients with type 2 diabetes mellitus. Int J Obes (Lond) 2007; 31:1302-10. [PMID: 17310221 DOI: 10.1038/sj.ijo.0803567] [Citation(s) in RCA: 128] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
OBJECTIVE To examine whether rosiglitazone alters gene expression of some key genes involved in mitochondrial biogenesis and oxidative capacity in skeletal muscle of type 2 diabetic patients, and whether this is associated with alterations in skeletal muscle oxidative capacity and lipid content. DESIGN measured in muscle biopsies obtained from diabetic patients, before and after 8 weeks of rosiglitazone treatment, and matched controls. Furthermore, whole-body insulin sensitivity and substrate utilization were assessed. SUBJECTS Ten obese type 2 diabetic patients and 10 obese normoglycemic controls matched for age and BMI. METHODS Gene expression and mitochondrial protein content of complexes I-V of the respiratory chain were measured by quantitative polymerase chain reaction and Western blotting, respectively. Histochemical staining was used to quantify lipid accumulation and complex II succinate dehydrogenase (SDH) activity. Insulin sensitivity and substrate utilization were measured during a hyperinsulinemic-euglycemic clamp with indirect calorimetry. RESULTS Skeletal-muscle mRNA of PGC-1 alpha and PPAR beta/delta--but not of other genes involved in glucose, fat and oxidative metabolism--was significantly lower in diabetic patients (P<0.01). Rosiglitazone significantly increased PGC-1 alpha ( approximately 2.2-fold, P<0.01) and PPAR beta/delta ( approximately 2.6-fold, P<0.01), in parallel with an increase in insulin sensitivity, SDH activity and metabolic flexibility (P<0.01). Surprisingly, none of the measured mitochondrial proteins was reduced in type 2 diabetic patients, nor affected by rosiglitazone treatment. No alterations were seen in muscular fat accumulation upon treatment. CONCLUSION These results suggest that the insulin-sensitizing effect of rosiglitazone may involve an effect on muscular oxidative capacity, via PGC-1 alpha and PPAR beta/delta, independent of mitochondrial protein content and/or changes in intramyocellular lipid.
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Affiliation(s)
- M Mensink
- Department of Human Biology, Nutrition and Toxicology Research Institute Maastricht (NUTRIM), Maastricht University, Maastricht, The Netherlands.
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Pontén EM, Stål PS. Decreased capillarization and a shift to fast myosin heavy chain IIx in the biceps brachii muscle from young adults with spastic paresis. J Neurol Sci 2006; 253:25-33. [PMID: 17196619 DOI: 10.1016/j.jns.2006.11.006] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2006] [Revised: 10/04/2006] [Accepted: 11/08/2006] [Indexed: 10/23/2022]
Abstract
Muscle spasticity and paresis are conditions that occur secondary to upper motor neuron lesions. The co-existence of decreased motor unit recruitment and intermittent over-activity generates confusion concerning the effect on muscle fiber characteristics. In order to increase the knowledge about the effect of upper motor lesion on capillarization and muscle fiber composition, the biceps brachii muscle from seven young adults with long duration of spastic paresis and seven age-matched controls were analyzed using morphological and enzyme- and immuno-histochemical techniques. The spastic muscles had a 38% lower capillary density (p=0.002), 30% fewer capillaries around each muscle fiber (p=0.02), and 16% fewer capillaries when related to the fiber size (p=0.04). The frequency of fibers expressing myosin heavy chain (MyHC) IIx increased (30% vs. 4%, p=0.006), while the percentage of fibers expressing MyHC I and MyHC IIa, respectively, decreased (22% vs. 46% and 7% vs. 29%, p<0.01). The high proportion of muscle fibers with low oxidative capacity and low capillary supply indicates that biceps brachii muscle from patients with upper motor lesions fatigue more easily than normal controls. We also observed a significantly higher variability in fiber size for fibers expressing MyHC I (p<0.04), and, in three of the subjects, a small amount of small fibers expressing developmental MyHCs was found. These results suggest that, although intermittent stretch reflex contractions might have an impact on the muscle characteristics in spastic paresis, the muscle phenotypic properties are more adapted to decreased voluntary motor unit recruitment.
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Affiliation(s)
- E M Pontén
- Department of Pediatric Orthopaedic Surgery, Astrid Lindgren Children's Hospital, Karolinska University Hospital, Stockholm, Sweden.
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Praet SFE, De Feyter HMM, Jonkers RAM, Nicolay K, van Pul C, Kuipers H, van Loon LJC, Prompers JJ. 31P MR spectroscopy and in vitro markers of oxidative capacity in type 2 diabetes patients. MAGNETIC RESONANCE MATERIALS IN PHYSICS BIOLOGY AND MEDICINE 2006; 19:321-31. [PMID: 17180611 DOI: 10.1007/s10334-006-0060-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2006] [Revised: 10/26/2006] [Accepted: 11/06/2006] [Indexed: 01/07/2023]
Abstract
BACKGROUND Skeletal muscle mitochondrial function in type 2 diabetes (T2D) is currently being studied intensively. In vivo (31)P magnetic resonance spectroscopy ((31)P MRS) is a noninvasive tool used to measure mitochondrial respiratory function (MIFU) in skeletal muscle tissue. However, microvascular co-morbidity in long-standing T2D can interfere with the (31)P MRS methodology. AIM To compare (31)P MRS-derived parameters describing in vivo MIFU with an in vitro assessment of muscle respiratory capacity and muscle fiber-type composition in T2D patients. METHODS (31)P MRS was applied in long-standing, insulin-treated T2D patients. (31)P MRS markers of MIFU were measured in the M. vastus lateralis. Muscle biopsy samples were collected from the same muscle and analyzed for succinate dehydrogenase activity (SDH) and fiber-type distribution. RESULTS Several (31)P MRS parameters of MIFU showed moderate to good correlations with the percentage of type I fibers and type I fiber-specific SDH activity (Pearson's R between 0.70 and 0.75). In vivo and in vitro parameters of local mitochondrial respiration also correlated well with whole-body fitness levels (VO (2peak)) in these patients (Pearson's R between 0.62 and 0.90). CONCLUSION Good correlations exist between in vivo and in vitro measurements of MIFU in long-standing insulin-treated T2D subjects, which are qualitatively and quantitatively consistent with previous results measured in healthy subjects. This justifies the use of (31)P MRS to measure MIFU in relation to T2D.
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Affiliation(s)
- S F E Praet
- Department of Movement Sciences, Nutrition and Toxicology Research Institute Maastricht, Maastricht University, 6200, MD, Maastricht, The Netherlands.
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36
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Dagberg B, Alstermark B. Improved organotypic cell culture model for analysis of the neuronal circuit involved in the monosynaptic stretch reflex. J Neurosci Res 2006; 84:460-9. [PMID: 16683231 DOI: 10.1002/jnr.20888] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Knowledge regarding neuronal circuit formation is central for the understanding of the vast network making up the brain. It is therefore necessary to find novel ways to analyze the mechanisms involved in well-defined neural circuits. We present an improved in vitro model of the monosynaptic stretch reflex circuit, based on primary organotypic cell cultures. By using limb tissue as a source of muscle fibers instead of circumspinal tissue we could make the in vitro system more in vivo like in the sense that it focuses on the stretch reflex involving limb muscles. Furthermore, our analyses showed that this procedure allows muscle fibers to follow the normal developmental pattern. Particularly interesting was the finding of slow tonic myosin heavy chain expressing muscle fibers, a developmental marker for muscle spindles, in the cultures showing that this system has the potential to contain the complete reflex circuits.
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Affiliation(s)
- Björn Dagberg
- Department of Integrative Medical Biology, Umeå University, Umeå, Sweden.
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37
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Ferrer-Martínez A, Montell E, Montori-Grau M, García-Martínez C, Gómez-Foix AM, Roberts MA, Mansourian R, Macé K. Long-term cultured human myotubes decrease contractile gene expression and regulate apoptosis-related genes. Gene 2006; 384:145-53. [PMID: 17052863 DOI: 10.1016/j.gene.2006.07.042] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2006] [Revised: 07/10/2006] [Accepted: 07/21/2006] [Indexed: 01/12/2023]
Abstract
The present study examined time-dependent changes in the gene expression profile of long-term cultured human myotubes. Microarray transcriptional analysis was performed in a primary culture of differentiated myotubes from one subject over seven weeks. This analysis showed a main gradual fall in genes of the contractile apparatus, and a broad upregulation of genes involved in cell development and growth, followed by stress response and signal transduction. Glucose metabolism was also monitored, but no significant alterations in glucose uptake, oxidation or glycogen storage were observed. Mitochondrial membrane potential, or the amount of membrane lipid peroxides, remained similarly unchanged, nor was lactate dehydrogenase leakage observed. Time-dependent changes in eight genes were validated by real-time RT-PCR in primary cultured myotubes from four subjects, of similar age and isolated after equivalent replication cycles in vitro and differentiated over seven weeks. Insulin-like growth factor-binding protein 2 (IGFBP2), a modulator of the IGF signal, was upregulated. The antiapoptotic gene heat-shock 70-kd protein 2 (HSPA2) was induced, whereas the proapoptotic tumor necrosis factor receptor superfamily, member 25 (WSL-1) was suppressed. A decline in the muscle-specific gene M-cadherin and contraction genes, such as slow-twitch troponin I (TNNI1) and myosin heavy chain 2 (MYH2), myosin light chain 1 (MYL1) and myosin-binding protein H (MYBPH), which are expressed in adult fast-twitch muscle, was shown. In summary, these data demonstrate extensive downregulation of contractile genes and modulation of apoptosis-related genes, in favour of cell survival, during maintenance of cultured human myotubes.
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Affiliation(s)
- Andreu Ferrer-Martínez
- Departament de Bioquímica i Biologia Molecular, Facultat de Biologia, Universitat de Barcelona, Diagonal 645, 08028-Barcelona, Spain
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Jazet IM, Ouwens DM, Schaart G, Pijl H, Keizer H, Maassen JA, Meinders AE. Effect of a 2-day very low-energy diet on skeletal muscle insulin sensitivity in obese type 2 diabetic patients on insulin therapy. Metabolism 2005; 54:1669-78. [PMID: 16311102 DOI: 10.1016/j.metabol.2005.06.017] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/08/2005] [Accepted: 06/30/2005] [Indexed: 11/29/2022]
Abstract
This study investigates the molecular mechanisms underlying the blood glucose-lowering effect of a 2-day very low-energy diet (VLED, 1883 kJ/d) in 12 obese (body mass index, 36.3 +/- 1.0 kg/m2 [mean +/- SEM]) type 2 diabetic (HbA(1C) 7.3% +/- 0.4%) patients simultaneously taken off all glucose-lowering therapy, including insulin. Endogenous glucose production (EGP) and glucose disposal ([6,6-2H2]-glucose) were measured before and after the VLED in basal and hyperinsulinemic (40 mU/m2 per minute) euglycemic conditions. Insulin signaling and expression of GLUT-4, FAT/CD36, and triglycerides were assessed in muscle biopsies, obtained before the clamp and after 30 minutes of hyperinsulinemia. Fasting plasma glucose decreased from 11.3 +/- 1.3 to 10.3 +/- 1.0 mmol/L because of a decreased basal EGP (14.2 +/- 1.0 to 11.9 +/- 0.7 micromol/kg per minute, P = .009). Insulin-stimulated glucose disposal did not change. No diet effect was found on the expression of the insulin receptor and insulin receptor substrate-1 or on phosphatidylinositol 3'-kinase activity, or on FAT/CD36 expression pattern, GLUT-4 translocation, or triglyceride distribution in either the basal or insulin-stimulated situation. Unexpectedly, basal PKB/Akt phosphorylation on T308 and S473 increased after the diet, at equal protein expression. In conclusion, a 2-day VLED lowers fasting plasma glucose via a decreased basal EGP without an effect on glucose disposal. Accordingly, no changes in activation of phosphatidylinositol 3'-kinase, triglyceride distribution, FAT/CD36 expression, and GLUT-4 translocation were found in skeletal muscle biopsies.
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Affiliation(s)
- Ingrid M Jazet
- Department of General Internal Medicine C-4-66, Leiden University Medical Center, 2333 ZA Leiden, The Netherlands.
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Dattena M, Chessa B, Lacerenza D, Accardo C, Pilichi S, Mara L, Chessa F, Vincenti L, Cappai P. Isolation, culture, and characterization of embryonic cell lines from vitrified sheep blastocysts. Mol Reprod Dev 2005; 73:31-9. [PMID: 16206132 DOI: 10.1002/mrd.20378] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
This study was conducted to isolate, to culture, and to characterize embryonic cell lines from in vitro produced vitrified sheep blastocysts. Embryos were produced and vitrified at the expanded blastocyst stage. Ten inner cell masses arising from day 6-7 blastocysts were isolated by immunosurgery, disaggregated, and cultured onto mitomocin-C-inactivated mouse STO fibroblasts (MIF). After 5 or 6 days of culture the primary cell colonies were disaggregated, seeded in a new MIF, and cultured for 3 or 4 days to form new colonies called Passage 1. These cells were then disaggregated and cultured for other two passages. The primary cell colonies and Passage 2 colonies expressed stage specific embryonic markers SSEA-1, SSEA-3, and SSEA-4, and were alkaline phosphatase positive. In the absence of feeder layer and human leukemia inhibitory factor (LIF), these cells differentiated into variety of cell types and formed embryoid bodies. When cultured for an extended period of time, embryoid bodies differentiated into derivatives of three embryonic germ (EG) layers. These were characterized by detection of specific markers for differentiation such early mesoderm (FE-C6), embryonic myosin (F1-652), neural precursor (FORSE-1), and endoderm (anti-cytokeratin 18). To our knowledge, this is the first time that embryonic cell lines from in vitro produced and vitrified ovine blastocysts have been isolated and examined for detection of SSEA markers, and embryoid bodies have been cultured and examined for specific cell surface markers for differentiation.
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Affiliation(s)
- M Dattena
- Istituto Zootecnico e Caseario per la Sardegna, Olmedo (SS), Italy.
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van Loon LJC, Koopman R, Manders R, van der Weegen W, van Kranenburg GP, Keizer HA. Intramyocellular lipid content in type 2 diabetes patients compared with overweight sedentary men and highly trained endurance athletes. Am J Physiol Endocrinol Metab 2004; 287:E558-65. [PMID: 15165998 DOI: 10.1152/ajpendo.00464.2003] [Citation(s) in RCA: 163] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Recent evidence suggests that intramyocellular lipid (IMCL) accretion is associated with obesity and the development of insulin resistance and/or type 2 diabetes. However, trained endurance athletes are markedly insulin sensitive, despite an elevated mixed muscle lipid content. In an effort to explain this metabolic paradox, we compared muscle fiber type-specific IMCL storage between populations known to have elevated IMCL deposits. Immunofluorescence microscopy was performed on muscle biopsies obtained from eight highly trained endurance athletes, eight type 2 diabetes patients, and eight overweight, sedentary men after an overnight fast. Mixed muscle lipid content was substantially greater in the endurance athletes (4.0 +/- 0.4% area lipid stained) compared with the diabetes patients and the overweight men (2.3 +/- 0.4 and 2.2 +/- 0.5%, respectively). More than 40% of the greater mixed muscle lipid content was attributed to a higher proportion type I muscle fibers (62 +/- 8 vs. 38 +/- 3 and 33 +/- 7%, respectively), which contained 2.8 +/- 0.3-fold more lipid than the type II fibers. The remaining difference was explained by a significantly greater IMCL content in the type I muscle fibers of the trained athletes. Differences in IMCL content between groups or fiber types were accounted for by differences in lipid droplet density, not lipid droplet size. IMCL distribution showed an exponential increase in lipid content from the central region toward the sarcolemma, which was similar between groups and fiber types. In conclusion, IMCL contents can be substantially greater in trained endurance athletes compared with overweight and/or type 2 diabetes patients. Because structural characteristics and intramyocellular distribution of lipid aggregates seem to be similar between groups, we conclude that elevated IMCL deposits are unlikely to be directly responsible for inducing insulin resistance.
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Affiliation(s)
- Luc J C van Loon
- Department of Movement Sciences, Nutrition Research Institute Maastricht, Maastricht University, 6200 MD Maastricht, The Netherlands.
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van Dam KG, van Breda E, Schaart G, van Ginneken MME, Wijnberg ID, de Graaf-Roelfsema E, van der Kolk JH, Keizer HA. Investigation of the expression and localization of glucose transporter 4 and fatty acid translocase/CD36 in equine skeletal muscle. Am J Vet Res 2004; 65:951-6. [PMID: 15281654 DOI: 10.2460/ajvr.2004.65.951] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To investigate the expression and localization of glucose transporter 4 (GLUT4) and fatty acid translocase (FAT/CD36) in equine skeletal muscle. SAMPLE POPULATION Muscle biopsy specimens obtained from 5 healthy Dutch Warmblood horses. PROCEDURES Percutaneous biopsy specimens were obtained from the vastus lateralis, pectoralis descendens, and triceps brachii muscles. Cryosections were stained with combinations of GLUT4 and myosin heavy chain (MHC) specific antibodies or FAT/CD36 and MHC antibodies to assess the fiber specific expression of GLUT4 and FAT/CD36 in equine skeletal muscle via indirect immunofluorescent microscopy. RESULTS Immunofluorescent staining revealed that GLUT4 was predominantly expressed in the cytosol of fast type 2B fibers of equine skeletal muscle, although several type 1 fibers in the vastus lateralis muscle were positive for GLUT4. In all muscle fibers examined microscopically, FAT/CD36 was strongly expressed in the sarcolemma and capillaries. Type 1 muscle fibers also expressed small intracellular amounts of FAT/CD36, but no intracellular FAT/CD36 expression was detected in type 2 fibers. CONCLUSIONS AND CLINICAL RELEVANCE In equine skeletal muscle, GLUT4 and FAT/CD36 are expressed in a fiber type selective manner.
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Affiliation(s)
- Klien G van Dam
- Department of Equine Sciences (Medicine Section), Faculty of Veterinary Medicine, Utrecht University, Yalelaan 16, NL-3584 CM Utrecht, The Netherlands
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Brazelton TR, Nystrom M, Blau HM. Significant differences among skeletal muscles in the incorporation of bone marrow-derived cells. Dev Biol 2003; 262:64-74. [PMID: 14512018 DOI: 10.1016/s0012-1606(03)00357-9] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
While numerous reports indicate that adult bone marrow-derived cells can contribute to nonhematopoietic tissues in vivo in adult mice, the generally low frequency of these events has made it difficult to study the molecular and cellular pathways involved. Here, we show a 1000-fold range in the frequency with which diverse skeletal muscles incorporate adult bone marrow-derived cells in adult mice. Most striking was the finding of one specific muscle, the panniculus carnosus, in which up to 5% of myofibers incorporated bone marrow-derived cells over a 16- month period in the absence of experimentally induced selective pressure. These results suggest that muscles differ physiologically, establishing the panniculus carnosus as an assay for identifying the key regulators, such as trophic, homing, and differentiation factors, as well as the relevant cells within the bone marrow that are capable of circulating throughout the periphery and contributing to adult, nonhematopoietic tissues, such as skeletal muscle. Finally, the 5% incorporation of adult stem cells into skeletal muscle is the highest reported to date in the absence of experimentally induced selective pressure and is at a level that may be consistent with improving the function of defective muscle tissue.
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Affiliation(s)
- Timothy R Brazelton
- Baxter Laboratory in Genetic Pharmacology, Stanford University School of Medicine, 269 W. Campus Drive, Stanford, CA 94305-5175, USA
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43
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van Loon LJC, Schrauwen-Hinderling VB, Koopman R, Wagenmakers AJM, Hesselink MKC, Schaart G, Kooi ME, Saris WHM. Influence of prolonged endurance cycling and recovery diet on intramuscular triglyceride content in trained males. Am J Physiol Endocrinol Metab 2003; 285:E804-11. [PMID: 12783774 DOI: 10.1152/ajpendo.00112.2003] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Intramuscular triglycerides (IMTG) are assumed to form an important substrate source during prolonged endurance exercise in trained males. This study investigated the effects of endurance exercise and recovery diet on IMTG content in vastus lateralis muscle. Nine male cyclists were provided with a standardized diet for 3 days, after which they performed a 3-h exercise trial at a 55% maximum workload. Before and immediately after exercise and after 24 and 48 h of recovery, magnetic resonance spectroscopy (MRS) was performed to quantitate IMTG content. Muscle biopsies were taken after 48 h of recovery to determine IMTG content by using quantitative fluorescence microscopy. The entire procedure was performed two times; in one trial, a normal diet containing 39% energy (En%) as fat was provided (NF) and in the other a typical carbohydrate-rich athlete's diet (LF: 24 En% fat) was provided. During exercise, IMTG content decreased by 21.4 +/- 3.1%. During recovery, IMTG content increased significantly in the NF trial only, reaching preexercise levels within 48 h. In accord with MRS, fluorescence microscopy showed significantly higher IMTG content in the NF compared with the LF trial, with differences restricted to the type I muscle fibers (2.1 +/- 0.2 vs. 1.4 +/- 0.2% area lipid staining, respectively). In conclusion, IMTG content in the vastus lateralis muscle declines significantly during prolonged endurance exercise in male cyclists. When a normal diet is used, IMTG contents are subsequently repleted within 48 h of postexercise recovery. In contrast, IMTG repletion is impaired substantially when a typical, carbohydrate-rich athlete's diet is used. Data obtained by quantitative fluorescence microscopy correspond well with MRS results, implying that both are valid methods to quantify IMTG content.
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Affiliation(s)
- Luc J C van Loon
- Department of Human Biology, Nutrition Research Institute Maastricht, Maastricht University, P.O. Box 616, 6200 MD Maastricht, The Netherlands.
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van Loon LJC, Koopman R, Stegen JHCH, Wagenmakers AJM, Keizer HA, Saris WHM. Intramyocellular lipids form an important substrate source during moderate intensity exercise in endurance-trained males in a fasted state. J Physiol 2003; 553:611-25. [PMID: 14514877 PMCID: PMC2343576 DOI: 10.1113/jphysiol.2003.052431] [Citation(s) in RCA: 144] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Both stable isotope methodology and fluorescence microscopy were applied to define the use of intramuscular triglyceride (IMTG) stores as a substrate source during exercise on a whole-body as well as on a fibre type-specific intramyocellular level in trained male cyclists. Following an overnight fast, eight subjects were studied at rest, during 120 min of moderate intensity exercise (60 % maximal oxygen uptake capacity (VO2,max)) and 120 min of post-exercise recovery. Continuous infusions of [U-13C]palmitate and [6,6-2H2]glucose were administered at rest and during subsequent exercise to quantify whole-body plasma free fatty acid (FFA) and glucose oxidation rates and the contribution of other fat sources (sum of muscle- plus lipoprotein-derived TG) and muscle glycogen to total energy expenditure. Fibre type-specific intramyocellular lipid content was determined in muscle biopsy samples collected before, immediately after and 2 h after exercise. At rest, fat oxidation provided 66 +/- 5 % of total energy expenditure, with FFA and other fat sources contributing 48 +/- 6 and 17 +/- 3 %, respectively. FFA oxidation rates increased during exercise, and correlated well with the change in plasma FFA concentrations. Both the use of other fat sources and muscle glycogen declined with the duration of exercise, whereas plasma glucose production and utilisation increased (P < 0.001). On average, FFA, other fat sources, plasma glucose and muscle glycogen contributed 28 +/- 3, 15 +/- 2, 12 +/- 1 and 45 +/- 4 % to total energy expenditure during exercise, respectively. Fluorescence microscopy revealed a 62 +/- 7 % net decline in muscle lipid content following exercise in the type I fibres only, with no subsequent change during recovery. We conclude that IMTG stores form an important substrate source during moderate intensity exercise in endurance-trained male athletes following an overnight fast, with the oxidation rate of muscle- plus lipoprotein-derived TG being decreased with the duration of exercise.
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Affiliation(s)
- Luc J C van Loon
- Nutrition Research Institute Maastricht, Maastricht University, Maastricht, The Netherlands.
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45
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Wigmore PM, Evans DJR. Molecular and cellular mechanisms involved in the generation of fiber diversity during myogenesis. INTERNATIONAL REVIEW OF CYTOLOGY 2002; 216:175-232. [PMID: 12049208 DOI: 10.1016/s0074-7696(02)16006-2] [Citation(s) in RCA: 84] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
Skeletal muscles have a characteristic proportion and distribution of fiber types, a pattern which is set up early in development. It is becoming clear that different mechanisms produce this pattern during early and late stages of myogenesis. In addition, there are significant differences between the formation of muscles in head and those found in rest of the body. Early fiber type differentiation is dependent upon an interplay between patterning systems which include the Wnt and Hox gene families and different myoblast populations. During later stages, innervation, hormones, and functional demand increasingly act to determine fiber type, but individual muscles still retain an intrinsic commitment to form particular fiber types. Head muscle is the only muscle not derived from the somites and follows a different development pathway which leads to the formation of particular fiber types not found elsewhere. This review discusses the formation of fiber types in both head and other muscles using results from both chick and mammalian systems.
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Affiliation(s)
- Peter M Wigmore
- School of Biomedical Sciences, Queen's Medical Centre, Nottingham, United Kingdom
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Hallauer PL, Hastings KEM. TnIfast IRE enhancer: multistep developmental regulation during skeletal muscle fiber type differentiation. Dev Dyn 2002; 224:422-31. [PMID: 12203734 DOI: 10.1002/dvdy.10122] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
To identify developmental steps leading to adult skeletal muscle fiber-type-specific gene expression, we carried out transgenic mouse studies of the IRE enhancer of the quail TnIfast gene. Histochemical analysis of IRE/herpesvirus tk promoter/beta-galactosidase reporter transgene expression in adult muscle directly demonstrated IRE-driven fast vs. slow fiber-type specificity, and IIB>IIX>IIA differential expression among the fast fiber types: patterns similar to those of native-promoter TnIfast constructs. These tissue- and cell-type specificities are autonomous to the IRE and do not depend on interactions with a muscle gene promoter. Developmental studies showed that the adult pattern of IRE-driven transgene expression emerges in three steps: (1) activation during the formation of primary embryonic (presumptive slow) muscle fibers; (2) activation, to markedly higher levels, during formation of secondary (presumptive fast) fibers, and (3) differential augmentation of expression during early postnatal maturation of the IIB, IIX, IIA fast fiber types. These results provide insight into the roles of gene activation and gene repression mechanisms in fiber-type specificity and can account for apparently disparate results obtained in previous studies of TnI isoform expression in development. Each of the three IRE-driven developmental steps is spatiotemporally associated with a different major regulatory event at the fast myosin heavy chain gene cluster, suggesting that diverse muscle gene families respond to common, or tightly integrated, regulatory signals during multiple steps of muscle fiber differentiation.
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MESH Headings
- Animals
- Cell Differentiation/physiology
- Embryo, Mammalian
- Embryo, Nonmammalian
- Enhancer Elements, Genetic
- Gene Expression Regulation, Developmental
- Genes, Reporter
- In Situ Hybridization
- Mice
- Mice, Transgenic
- Multigene Family
- Muscle Development
- Muscle Fibers, Fast-Twitch/cytology
- Muscle Fibers, Fast-Twitch/physiology
- Muscle Fibers, Slow-Twitch/physiology
- Muscle, Skeletal/cytology
- Muscle, Skeletal/embryology
- Muscle, Skeletal/physiology
- Promoter Regions, Genetic
- Protein Isoforms/genetics
- Protein Isoforms/metabolism
- Quail
- Transcriptional Activation
- Transgenes
- Troponin I/genetics
- Troponin I/metabolism
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Affiliation(s)
- Patricia L Hallauer
- Montreal Neurological Institute, and Department of Biology, McGill University, Montreal, QC, Canada
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Mitalipova M, Beyhan Z, First NL. Pluripotency of bovine embryonic cell line derived from precompacting embryos. CLONING 2002; 3:59-67. [PMID: 11900640 DOI: 10.1089/15204550152475563] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
We report herein the establishment of three bovine pluripotent embryonic cell lines derived from 8-16-cell precompacting embryos. Two cell lines were cultured for 10 passages and underwent spontaneous differentiation. One cell line (Z2) has been cultured continuously for over 3 years and has remained undifferentiated. These cells express cell surface markers that have been used routinely to characterize embryonic stem (ES) and embryonic germ (EG) cells in other species such as stage-specific embryonic antigens SSEA-1, SSEA-3, and SSEA-4, and c-Kit receptor. In the absence of a feeder layer, these cells differentiated into a variety of cell types and formed embryoid bodies (EBs). When cultured for an extended period of time, EBs differentiated into derivatives of three EG layers - mesoderm, ectoderm, and endoderm - which were characterized by detection of specific cell surface markers. Our results indicate that the Z2 cell line is pluripotent and resembles an ES cell line. To our knowledge, this is the first bovine embryonic cell line that has remained pluripotent in culture for more than 150 passages.
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Abstract
The aim of the present study was to investigate whether histopathological changes can be detected in two soft palate muscles, the palatopharyngeus and the uvula, in 11 patients with long duration of sleep-disordered breathing (SDB). Muscle samples were collected from patients undergoing uvulo-palatopharyngoplasty (UPPP). Reference samples from the corresponding areas were obtained at autopsy from five previously healthy subjects. Muscle morphology, fibre type and myosin heavy chain (MyHC) compositions were analysed with enzyme-histochemical, immunohistochemical and biochemical techniques. The muscle samples from the patients, and especially those from the palatopharyngeus, showed several morphological abnormalities. The most striking findings were (i) increased amount of connective tissue, (ii) abnormal variability in fibre size, (iii) increased proportion of small-sized fibres, (iv) alterations in fibre type and MyHC compositions, (v) increased frequency of fibres containing developmental MyHC isoforms. Our findings point towards a pathological process of denervation and degeneration in the patient samples. Conclusively, the morphological abnormalities suggest a neuromuscular disorder of the soft palate in SDB patients.
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Affiliation(s)
- Rolf Lindman
- Department of Oral and Maxillofacial Surgery and Jaw Orthopedics, Malmö University Hospital, Malmö, Sweden
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Bonavaud S, Agbulut O, D'Honneur G, Nizard R, Mouly V, Butler-Browne G. Preparation of isolated human muscle fibers: a technical report. In Vitro Cell Dev Biol Anim 2002; 38:66-72. [PMID: 11928997 DOI: 10.1290/1071-2690(2002)038<0066:poihmf>2.0.co;2] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The aim of this study was to develop a technique to culture satellite cells from isolated intact fast or slow human muscle fibers. Previous studies have been carried out on small rodent muscles where the fibers run from tendon to tendon, but this is the first description of the modification of this technique for much larger human muscles. We have demonstrated that the human muscle fibers are in fact segmental, and we have also shown that it is possible to obtain very pure satellite cell cultures. We discuss the importance of this technique as a source of highly purified muscle cell cultures, which can be used for further studies on satellite cell behavior.
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Affiliation(s)
- Sylvie Bonavaud
- UMR CNRS 7000, Faculté de Médecine Pitié-Salpétrière, Paris, France
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Hallauer PL, Hastings KEM. Coregulation of fast contractile protein transgene and glycolytic enzyme expression in mouse skeletal muscle. Am J Physiol Cell Physiol 2002; 282:C113-24. [PMID: 11742804 DOI: 10.1152/ajpcell.00294.2001] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Little is known of the gene regulatory mechanisms that coordinate the contractile and metabolic specializations of skeletal muscle fibers. Here we report a novel connection between fast isoform contractile protein transgene and glycolytic enzyme expression. In quantitative histochemical studies of transgenic mouse muscle fibers, we found extensive coregulation of the glycolytic enzyme glycerol-3-phosphate dehydrogenase (GPDH) and transgene constructs based on the fast skeletal muscle troponin I (TnIfast) gene. In addition to a common IIB > IIX > IIA fiber type pattern, TnIfast transgenes and GPDH showed correlated fiber-to-fiber variation within each fast fiber type, concerted emergence of high-level expression during early postnatal muscle maturation, and parallel responses to muscle under- or overloading. Regulatory information for GPDH-coregulated expression is carried by the TnIfast first-intron enhancer (IRE). These results identify an unexpected contractile/metabolic gene regulatory link that is amenable to further molecular characterization. They also raise the possibility that the equal expression in all fast fiber types observed for the endogenous TnIfast gene may be driven by different metabolically coordinated mechanisms in glycolytic (IIB) vs. oxidative (IIA) fast fibers.
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Affiliation(s)
- Patricia L Hallauer
- Montreal Neurological Institute and Biology Department, McGill University, Montreal, Quebec, Canada H3A 2B4
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