801
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Myf5-positive satellite cells contribute to Pax7-dependent long-term maintenance of adult muscle stem cells. Cell Stem Cell 2013; 13:590-601. [PMID: 23933088 DOI: 10.1016/j.stem.2013.07.016] [Citation(s) in RCA: 206] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2012] [Revised: 07/12/2013] [Accepted: 07/19/2013] [Indexed: 11/21/2022]
Abstract
Skeletal muscle contains Pax7-expressing muscle stem or satellite cells, enabling muscle regeneration throughout most of adult life. Here, we demonstrate that induced inactivation of Pax7 in Pax7-expressing cells of adult mice leads to loss of muscle stem cells and reduced heterochromatin condensation in rare surviving satellite cells. Inactivation of Pax7 in Myf5-expressing cells revealed that the majority of adult muscle stem cells originate from myogenic lineages, which express the myogenic regulators Myf5 or MyoD. Likewise, the majority of muscle stem cells are replenished from Myf5-expressing myogenic cells during adult life, and inactivation of Pax7 in Myf5-expressing cells after muscle damage leads to a complete arrest of muscle regeneration. Finally, we demonstrate that a relatively small number of muscle stem cells are sufficient for efficient repair of skeletal muscles. We conclude that Pax7 acts at different levels in a nonhierarchical regulatory network controlling muscle-satellite-cell-mediated muscle regeneration.
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802
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Abstract
In this issue of Cell Metabolism, Mounier et al. (2013) show that AMPKα1 is a crucial contributor to the regeneration of damaged muscle tissues, acting in macrophages at the nexus between proinflammatory debris removal and resolution of muscle tissue inflammation.
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Affiliation(s)
- Venkatesh Krishnan
- Bone-Muscle-Joint-Urology, Lilly Research Laboratories, Indianapolis, IN 46225, USA.
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803
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Ieronimakis N, Pantoja M, Hays AL, Dosey TL, Qi J, Fischer KA, Hoofnagle AN, Sadilek M, Chamberlain JS, Ruohola-Baker H, Reyes M. Increased sphingosine-1-phosphate improves muscle regeneration in acutely injured mdx mice. Skelet Muscle 2013; 3:20. [PMID: 23915702 PMCID: PMC3750760 DOI: 10.1186/2044-5040-3-20] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2012] [Accepted: 05/22/2013] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND Presently, there is no effective treatment for the lethal muscle wasting disease Duchenne muscular dystrophy (DMD). Here we show that increased sphingosine-1-phoshate (S1P) through direct injection or via the administration of the small molecule 2-acetyl-4(5)-tetrahydroxybutyl imidazole (THI), an S1P lyase inhibitor, has beneficial effects in acutely injured dystrophic muscles of mdx mice. METHODS We treated mdx mice with and without acute injury and characterized the histopathological and functional effects of increasing S1P levels. We also tested exogenous and direct administration of S1P on mdx muscles to examine the molecular pathways under which S1P promotes regeneration in dystrophic muscles. RESULTS Short-term treatment with THI significantly increased muscle fiber size and extensor digitorum longus (EDL) muscle specific force in acutely injured mdx limb muscles. In addition, the accumulation of fibrosis and fat deposition, hallmarks of DMD pathology and impaired muscle regeneration, were lower in the injured muscles of THI-treated mdx mice. Furthermore, increased muscle force was observed in uninjured EDL muscles with a longer-term treatment of THI. Such regenerative effects were linked to the response of myogenic cells, since intramuscular injection of S1P increased the number of Myf5nlacz/+ positive myogenic cells and newly regenerated myofibers in injured mdx muscles. Intramuscular injection of biotinylated-S1P localized to muscle fibers, including newly regenerated fibers, which also stained positive for S1P receptor 1 (S1PR1). Importantly, plasma membrane and perinuclear localization of phosphorylated S1PR1 was observed in regenerating muscle fibers of mdx muscles. Intramuscular increases of S1P levels, S1PR1 and phosphorylated ribosomal protein S6 (P-rpS6), and elevated EDL muscle specific force, suggest S1P promoted the upregulation of anabolic pathways that mediate skeletal muscle mass and function. CONCLUSIONS These data show that S1P is beneficial for muscle regeneration and functional gain in dystrophic mice, and that THI, or other pharmacological agents that raise S1P levels systemically, may be developed into an effective treatment for improving muscle function and reducing the pathology of DMD.
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Affiliation(s)
- Nicholas Ieronimakis
- Department of Pathology, School of Medicine, University of Washington, Seattle, WA 98195, USA.
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804
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Fanzani A, Monti E, Donato R, Sorci G. Muscular dystrophies share pathogenetic mechanisms with muscle sarcomas. Trends Mol Med 2013; 19:546-54. [PMID: 23890422 DOI: 10.1016/j.molmed.2013.07.001] [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: 12/14/2012] [Revised: 06/27/2013] [Accepted: 07/01/2013] [Indexed: 12/27/2022]
Abstract
Several lines of recent evidence have opened a new debate on the mechanisms underlying the genesis of rhabdomyosarcoma, a pediatric soft tissue tumor with a widespread expression of muscle-specific markers. In particular, it is increasingly evident that the loss of skeletal muscle integrity observed in some mouse models of muscular dystrophy can favor rhabdomyosarcoma formation. This is especially true in old age. Here, we review these experimental findings and focus on the main molecular and cellular events that can dictate the tumorigenic process in dystrophic muscle, such as the loss of structural or regulatory proteins with tumor suppressor activity, the impaired DNA damage response due to oxidative stress, the chronic inflammation and the conflicting signals arising within the degenerated muscle niche.
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Affiliation(s)
- Alessandro Fanzani
- Department of Molecular and Translational Medicine and Interuniversity Institute of Myology (IIM), University of Brescia, Viale Europa 11, Brescia, 25123, Italy.
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805
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Abstract
Increasing attention is currently devoted to the multiple roles that pericytes (also defined as mural, Rouget, or perivascular cells) may play during angiogenesis, vascular homeostasis, and pathology. Many recent excellent reviews thoroughly address these topics (see below); hence, we will not discuss them in detail here. However, not much is known about origin, heterogeneity, gene expression, and developmental potential of pericytes during fetal and postnatal development. This is likely because of the paucity of markers expressed by pericytes and the absence of truly unique ones. Thus, in vivo identification and ex perspective isolation are challenging and explain the relative little data available in comparison with neighbor but far more characterized cells such as the endothelium. Despite this preliminary knowledge, we will propose that contribution to growing mesoderm tissues may be an important role for pericytes. Thus, their ability to contribute to tissue regeneration may be a consequence of their role in tissue growth. However, in a severely damaged or diseased tissue, acute or chronic inflammation likely results in the production of signaling molecules that are different from those present in developing tissues, thus explaining why pericytes are easily diverted from a regenerative to a fibrotic fate.
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Affiliation(s)
- Ornella Cappellari
- Department of Cell and Developmental Biology, University College London, United Kingdom
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806
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Montarras D, L'honoré A, Buckingham M. Lying low but ready for action: the quiescent muscle satellite cell. FEBS J 2013; 280:4036-50. [DOI: 10.1111/febs.12372] [Citation(s) in RCA: 147] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2013] [Revised: 05/24/2013] [Accepted: 05/28/2013] [Indexed: 12/21/2022]
Affiliation(s)
- Didier Montarras
- Department of Developmental and Stem Cell Biology; CNRS URA 2578; Institut Pasteur; Paris; France
| | - Aurore L'honoré
- Department of Developmental and Stem Cell Biology; CNRS URA 2578; Institut Pasteur; Paris; France
| | - Margaret Buckingham
- Department of Developmental and Stem Cell Biology; CNRS URA 2578; Institut Pasteur; Paris; France
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807
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Borthwick LA, Wynn TA, Fisher AJ. Cytokine mediated tissue fibrosis. BIOCHIMICA ET BIOPHYSICA ACTA 2013; 1832:1049-60. [PMID: 23046809 PMCID: PMC3787896 DOI: 10.1016/j.bbadis.2012.09.014] [Citation(s) in RCA: 289] [Impact Index Per Article: 24.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2012] [Revised: 09/28/2012] [Accepted: 09/29/2012] [Indexed: 12/20/2022]
Abstract
Acute inflammation is a recognised part of normal wound healing. However, when inflammation fails to resolve and a chronic inflammatory response is established this process can become dysregulated resulting in pathological wound repair, accumulation of permanent fibrotic scar tissue at the site of injury and the failure to return the tissue to normal function. Fibrosis can affect any organ including the lung, skin, heart, kidney and liver and it is estimated that 45% of deaths in the western world can now be attributed to diseases where fibrosis plays a major aetiological role. In this review we examine the evidence that cytokines play a vital role in the acute and chronic inflammatory responses that drive fibrosis in injured tissues. This article is part of a Special Issue entitled: Fibrosis: Translation of basic research to human disease.
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Affiliation(s)
- Lee A Borthwick
- Tissue Fibrosis and Repair Group, Institute of Cellular Medicine, Medical School, Newcastle University, Newcastle Upon Tyne, NE2 4HH, UK; Immunopathogenesis Section, Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA.
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808
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Six1 regulates MyoD expression in adult muscle progenitor cells. PLoS One 2013; 8:e67762. [PMID: 23840772 PMCID: PMC3695946 DOI: 10.1371/journal.pone.0067762] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2013] [Accepted: 05/22/2013] [Indexed: 12/21/2022] Open
Abstract
Quiescent satellite cells are myogenic progenitors that enable regeneration of skeletal muscle. One of the early events of satellite cell activation following myotrauma is the induction of the myogenic regulatory factor MyoD, which eventually induces terminal differentiation and muscle function gene expression. The purpose of this study was to elucidate the mechanism by which MyoD is induced during activation of satellite cells in mouse muscle undergoing regeneration. We show that Six1, a transcription factor essential for embryonic myogenesis, also regulates MyoD expression in muscle progenitor cells. Six1 knock-down by RNA interference leads to decreased expression of MyoD in myoblasts. Chromatin immunoprecipitation assays reveal that Six1 binds the Core Enhancer Region of MyoD. Further, transcriptional reporter assays demonstrate that Core Enhancer Region reporter gene activity in myoblasts and in regenerating muscle depends on the expression of Six1 and on Six1 binding sites. Finally, we provide evidence indicating that Six1 is required for the proper chromatin structure at the Core Enhancer Region, as well as for MyoD binding at its own enhancer. Together, our results reveal that MyoD expression in satellite cells depends on Six1, supporting the idea that Six1 plays an important role in adult myogenesis, in addition to its role in embryonic muscle formation.
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809
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Judson RN, Zhang RH, Rossi FMA. Tissue-resident mesenchymal stem/progenitor cells in skeletal muscle: collaborators or saboteurs? FEBS J 2013; 280:4100-8. [PMID: 23763717 DOI: 10.1111/febs.12370] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2013] [Revised: 05/17/2013] [Accepted: 05/28/2013] [Indexed: 12/11/2022]
Abstract
Although the regenerative potential of adult skeletal muscle is maintained by satellite cells, other stem/progenitor cell populations also reside in skeletal muscle. These heterogeneous cellular pools with mesenchymal lineage potentially play important roles in tissue homeostasis, with reciprocal collaborations between these cells and satellite cells appearing critical for effective regeneration. However, in disease settings, these mesenchymal stem/progenitors adopt a more sinister role - likely providing a major source of fibrosis, fatty tissue and extracellular matrix protein deposition in dystrophic tissue. Development of therapies for muscle degeneration therefore requires complete understanding of the multiple cell types involved and their complex interactions.
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Affiliation(s)
- Robert N Judson
- Biomedical Research Centre, Department of Medical Genetics, University of British Columbia, Vancouver, BC, Canada.
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810
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Paylor B, Fernandes J, McManus B, Rossi F. Tissue-resident Sca1+ PDGFRα+ mesenchymal progenitors are the cellular source of fibrofatty infiltration in arrhythmogenic cardiomyopathy. F1000Res 2013; 2:141. [PMID: 24358871 PMCID: PMC3790611 DOI: 10.12688/f1000research.2-141.v1] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 06/12/2013] [Indexed: 01/14/2023] Open
Abstract
Arrhythmogenic cardiomyopathy (AC) is a disease of the heart involving myocardial dystrophy leading to fibrofatty scarring of the myocardium and is associated with an increased risk of both ventricular arrhythmias and sudden cardiac death. It often affects the right ventricle but may also involve the left. Although there has been significant progress in understanding the role of underlying desmosomal genetic defects in AC, there is still a lack of data regarding the cellular processes involved in its progression. The development of cardiac fibrofatty scarring is known to be a principal pathological process associated with ventricular arrhythmias, and it is vital that we elucidate the role of various cell populations involved in the disease if targeted therapeutics are to be developed. The known role of mesenchymal progenitor cells in the reparative process of both the heart and skeletal muscle has provided inspiration for the identification of the cellular basis of fibrofatty infiltration in AC. Here we hypothesize that reparative processes triggered by myocardial degeneration lead to the differentiation of tissue-resident Sca1+ PDGFRα+ mesenchymal progenitors into adipocytes and fibroblasts, which compose the fibrofatty lesions characteristic of AC.
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Affiliation(s)
- Ben Paylor
- Biomedical Research Center, University of British Columbia, Vancouver , V6T 1Z3, Canada
| | - Justin Fernandes
- Biomedical Research Center, University of British Columbia, Vancouver , V6T 1Z3, Canada
| | - Bruce McManus
- James Hogg Research Centre, University of British Columbia, Vancouver, V6Z 1Y6, Canada
| | - Fabio Rossi
- Biomedical Research Center, University of British Columbia, Vancouver , V6T 1Z3, Canada
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811
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Green CJ, Bunprajun T, Pedersen BK, Scheele C. Physical activity is associated with retained muscle metabolism in human myotubes challenged with palmitate. J Physiol 2013; 591:4621-35. [PMID: 23774280 DOI: 10.1113/jphysiol.2013.251421] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
The aim of this study was to investigate whether physical activity is associated with preserved muscle metabolism in human myotubes challenged with saturated fatty acids. Human muscle satellite cells were isolated from sedentary or active individuals and differentiated into myocytes in culture. Metabolic differences were then investigated in the basal state or after chronic palmitate treatment. At basal, myocytes from sedentary individuals exhibited higher CD36 and HSP70 protein expression as well as elevated phosphorylation of c-Jun NH2-terminal kinase (JNK) and insulin receptor substrate 1 (IRS1) serine(307) compared to myocytes from active individuals. Despite equal lipid accumulation following palmitate treatment, myocytes from sedentary individuals exhibited delayed acetyl coenzyme A carboxylase phosphorylation compared to the active group. Myocytes from sedentary individuals had significantly higher basal glucose uptake and palmitate promoted insulin resistance in sedentary myocytes. Importantly, myocytes from active individuals were partially protected from palmitate-induced insulin resistance. Palmitate treatment enhanced IRS1 serine307 phosphorylation in myocytes from sedentary individuals and correlated positively to JNK phosphorylation. In conclusion, muscle satellite cells retain metabolic differences associated with physical activity. Physical activity partially protects myocytes from fatty acid-induced insulin resistance and inactivity is associated with dysregulation of metabolism in satellite cells challenged with palmitate. Although the benefits of physical activity on whole body physiology have been well investigated, this paper presents novel findings that both diet and exercise impact satellite cells directly. Given the fact that satellite cells are important for muscle maintenance, a dysregulated function could have profound effects on health. Therefore the effects of lifestyle on satellite cells needs to be delineated.
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Affiliation(s)
- C J Green
- C. J. Green: Centre of Inflammation and Metabolism, Rigshospitalet - Section 7641, Blegdamsvej 9, DK-2100, Copenhagen, Denmark.
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812
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Gumucio JP, Flood MD, Phan AC, Brooks SV, Mendias CL. Targeted inhibition of TGF-β results in an initial improvement but long-term deficit in force production after contraction-induced skeletal muscle injury. J Appl Physiol (1985) 2013; 115:539-45. [PMID: 23766498 DOI: 10.1152/japplphysiol.00374.2013] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Transforming growth factor-β (TGF-β) is a proinflammatory cytokine that regulates the response of many tissues following injury. Previous studies in our lab have shown that treating muscles with TGF-β results in a dramatic accumulation of type I collagen, substantial fiber atrophy, and a marked decrease in force production. Because TGF-β promotes atrophy and fibrosis, our objective was to investigate whether the inhibition of TGF-β after injury would enhance the recovery of muscle following injury. We hypothesized that inhibiting TGF-β after contraction-induced injury would improve the functional recovery of muscles by preventing muscle fiber atrophy and weakness, and by limiting the accumulation of fibrotic scar tissue. To test this hypothesis, we induced an injury using a series of in situ lengthening contractions to extensor digitorum longus muscles of mice treated with either a bioneutralizing antibody against TGF-β or a sham antibody. Compared with controls, muscles from mice receiving TGF-β inhibitor showed a greater recovery in force 3 days and 7 days after injury but had a decrease in force compared with controls at the 21-day time point. The early enhancement in force in the TGF-β inhibitor group was associated with an initial improvement in tissue morphology, but, at 21 days, while the control group was fully recovered, the TGF-β inhibitor group displayed an irregular extracellular matrix and an increase in atrogin-1 gene expression. These results indicate that the inhibition of TGF-β promotes the early recovery of muscle function but is detrimental overall to full muscle recovery following moderate to severe muscle injuries.
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Affiliation(s)
- Jonathan P Gumucio
- Department of Orthopaedic Surgery, University of Michigan Medical School, Ann Arbor, Michigan 48109-2200, USA
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813
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Bentzinger CF, Wang YX, von Maltzahn J, Soleimani VD, Yin H, Rudnicki MA. Fibronectin regulates Wnt7a signaling and satellite cell expansion. Cell Stem Cell 2013; 12:75-87. [PMID: 23290138 DOI: 10.1016/j.stem.2012.09.015] [Citation(s) in RCA: 272] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2011] [Revised: 06/07/2012] [Accepted: 09/14/2012] [Indexed: 01/07/2023]
Abstract
The influence of the extracellular matrix (ECM) within the stem cell niche remains poorly understood. We found that Syndecan-4 (Sdc4) and Frizzled-7 (Fzd7) form a coreceptor complex in satellite cells and that binding of the ECM glycoprotein Fibronectin (FN) to Sdc4 stimulates the ability of Wnt7a to induce the symmetric expansion of satellite stem cells. Newly activated satellite cells dynamically remodel their niche via transient high-level expression of FN. Knockdown of FN in prospectively isolated satellite cells severely impaired their ability to repopulate the satellite cell niche. Conversely, in vivo overexpression of FN with Wnt7a dramatically stimulated the expansion of satellite stem cells in regenerating muscle. Therefore, activating satellite cells remodel their niche through autologous expression of FN that provides feedback to stimulate Wnt7a signaling through the Fzd7/Sdc4 coreceptor complex. Thus, FN and Wnt7a together regulate the homeostatic levels of satellite stem cells and satellite myogenic cells during regenerative myogenesis.
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Affiliation(s)
- C Florian Bentzinger
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, ON, Canada
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814
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Pannérec A, Formicola L, Besson V, Marazzi G, Sassoon DA. Defining skeletal muscle resident progenitors and their cell fate potentials. Development 2013; 140:2879-91. [PMID: 23739133 DOI: 10.1242/dev.089326] [Citation(s) in RCA: 107] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The satellite cell is the major tissue-resident stem cell underlying muscle regeneration; however, multiple non-satellite myogenic progenitors as well as non-myogenic populations that support the muscle regenerative process have been identified. PW1 is expressed in satellite cells as well as in a subset of interstitial cells with myogenic potential termed PICs (PW1+ interstitial cells). Microarray profiling revealed that PICs express a broad range of genes common to mesenchymal stem cells, whereas satellite cells express genes consistent with a committed myogenic progenitor. Isolated PICs from both young and adult muscles can differentiate into smooth and skeletal muscle and fat whereas satellite cells are restricted to a skeletal muscle fate. We demonstrate that the adipogenic potential of PICs corresponds to a subpopulation that expresses platelet derived growth factor receptor alpha (PDGFRα) and overlaps with the recently described interstitial adipogenic progenitors. By contrast, PICs with myogenic potential do not express PDGFRα. Moreover, we observe a discrete and transient population of juvenile PICs based upon SCA1 expression that disappears by 3 weeks of postnatal development coincident with a switch in the cellular and genetic mechanisms underlying postnatal muscle growth.
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Affiliation(s)
- Alice Pannérec
- Myology Group, UMR S 787 INSERM, University of Pierre and Marie Curie Paris VI, Paris 75634, France
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815
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Sirabella D, De Angelis L, Berghella L. Sources for skeletal muscle repair: from satellite cells to reprogramming. J Cachexia Sarcopenia Muscle 2013; 4:125-36. [PMID: 23314905 PMCID: PMC3684700 DOI: 10.1007/s13539-012-0098-y] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/14/2012] [Accepted: 11/28/2012] [Indexed: 02/07/2023] Open
Abstract
Skeletal muscle regeneration is the process that ensures tissue repair after damage by injury or in degenerative diseases such as muscular dystrophy. Satellite cells, the adult skeletal muscle progenitor cells, are commonly considered to be the main cell type involved in skeletal muscle regeneration. Their mechanism of action in this process is extensively characterized. However, evidence accumulated in the last decade suggests that other cell types may participate in skeletal muscle regeneration. Although their actual contribution to muscle formation and regeneration is still not clear; if properly manipulated, these cells may become new suitable and powerful sources for cell therapy of skeletal muscle degenerative diseases. Mesoangioblasts, vessel associated stem/progenitor cells with high proliferative, migratory and myogenic potential, are very good candidates for clinical applications and are already in clinical experimentation. In addition, pluripotent stem cells are very promising sources for regeneration of most tissues, including skeletal muscle. Conditions such as muscle cachexia or aging that severely alter homeostasis may be counteracted by transplantation of donor and/or recruitment and activation of resident muscle stem/progenitor cells. Advantages and limitations of different cell therapy approaches will be discussed.
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Affiliation(s)
- Dario Sirabella
- />Department of Biomedical Engineering, Columbia University, 2920 Broadway, New York, NY 10027-7164 USA
| | - Luciana De Angelis
- />DAHFMO, Unit of Histology and Medical Embryology, University of Roma “La Sapienza”, Via Scarpa, 14, 00161 Rome, Italy
| | - Libera Berghella
- />IRCCS Fondazione S. Lucia, Via del Fosso di Fiorano, 64, 00143 Rome, Italy
- />HudsonAlpha Institute for Biotechnology, 601 Genome Way, Huntsville, AL 35806 USA
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816
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Siegel AL, Gurevich DB, Currie PD. A myogenic precursor cell that could contribute to regeneration in zebrafish and its similarity to the satellite cell. FEBS J 2013; 280:4074-88. [PMID: 23607511 DOI: 10.1111/febs.12300] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2013] [Accepted: 04/12/2013] [Indexed: 11/28/2022]
Abstract
The cellular basis for mammalian muscle regeneration has been an area of intense investigation over recent decades. The consensus is that a specialized self-renewing stem cell, termed the satellite cell, plays a major role during the process of regeneration in amniotes. How broadly this mechanism is deployed within the vertebrate phylogeny remains an open question. A lack of information on the role of cells analogous to the satellite cell in other vertebrate systems is even more unexpected given the fact that satellite cells were first designated in frogs. An intriguing aspect of this debate is that a number of amphibia and many fish species exhibit epimorphic regenerative processes in specific tissues, whereby regeneration occurs by the dedifferentiation of the damaged tissue, without deploying specialized stem cell populations analogous to satellite cells. Hence, it is feasible that a cellular process completely distinct from that deployed during mammalian muscle regeneration could operate in species capable of epimorphic regeneration. In this minireview, we examine the evidence for the broad phylogenetic distribution of satellite cells. We conclude that, in the vertebrates examined so far, epimorphosis does not appear to be deployed during muscle regeneration, and that analogous cells expressing similar marker genes to satellite cells appear to be deployed during the regenerative process. However, the functional definition of these cells as self-renewing muscle stem cells remains a final hurdle to the definition of the satellite cell as a generic vertebrate cell type.
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Affiliation(s)
- Ashley L Siegel
- Australian Regenerative Medicine Institute, Monash University, Clayton, Victoria, Australia.
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817
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Sakai H, Sato T, Sakurai H, Yamamoto T, Hanaoka K, Montarras D, Sehara-Fujisawa A. Fetal skeletal muscle progenitors have regenerative capacity after intramuscular engraftment in dystrophin deficient mice. PLoS One 2013; 8:e63016. [PMID: 23671652 PMCID: PMC3650009 DOI: 10.1371/journal.pone.0063016] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2013] [Accepted: 03/27/2013] [Indexed: 12/13/2022] Open
Abstract
Muscle satellite cells (SCs) are stem cells that reside in skeletal muscles and contribute to regeneration upon muscle injury. SCs arise from skeletal muscle progenitors expressing transcription factors Pax3 and/or Pax7 during embryogenesis in mice. However, it is unclear whether these fetal progenitors possess regenerative ability when transplanted in adult muscle. Here we address this question by investigating whether fetal skeletal muscle progenitors (FMPs) isolated from Pax3GFP/+ embryos have the capacity to regenerate muscle after engraftment into Dystrophin-deficient mice, a model of Duchenne muscular dystrophy. The capacity of FMPs to engraft and enter the myogenic program in regenerating muscle was compared with that of SCs derived from adult Pax3GFP/+ mice. Transplanted FMPs contributed to the reconstitution of damaged myofibers in Dystrophin-deficient mice. However, despite FMPs and SCs having similar myogenic ability in culture, the regenerative ability of FMPs was less than that of SCs in vivo. FMPs that had activated MyoD engrafted more efficiently to regenerate myofibers than MyoD-negative FMPs. Transcriptome and surface marker analyses of these cells suggest the importance of myogenic priming for the efficient myogenic engraftment. Our findings suggest the regenerative capability of FMPs in the context of muscle repair and cell therapy for degenerative muscle disease.
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MESH Headings
- Animals
- Cells, Cultured
- Dystrophin/deficiency
- Dystrophin/genetics
- Green Fluorescent Proteins/genetics
- Green Fluorescent Proteins/metabolism
- Immunohistochemistry
- Injections, Intramuscular
- Mice
- Mice, Knockout
- Mice, Transgenic
- Muscle, Skeletal/cytology
- Muscle, Skeletal/embryology
- Muscular Dystrophy, Animal/genetics
- Muscular Dystrophy, Animal/physiopathology
- Muscular Dystrophy, Animal/surgery
- Muscular Dystrophy, Duchenne/genetics
- Muscular Dystrophy, Duchenne/physiopathology
- Muscular Dystrophy, Duchenne/surgery
- MyoD Protein/genetics
- MyoD Protein/metabolism
- Myoblasts, Skeletal/metabolism
- Myoblasts, Skeletal/transplantation
- Myofibrils/genetics
- Myofibrils/physiology
- Myogenin/genetics
- Myogenin/metabolism
- PAX3 Transcription Factor
- Paired Box Transcription Factors/genetics
- Paired Box Transcription Factors/metabolism
- Regeneration/physiology
- Reverse Transcriptase Polymerase Chain Reaction
- Satellite Cells, Skeletal Muscle/transplantation
- Stem Cell Transplantation/methods
- Transcriptome
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Affiliation(s)
- Hiroshi Sakai
- Department of Growth Regulation, Institute for Frontier Medical Sciences, Kyoto University, Kyoto, Japan
| | - Takahiko Sato
- Department of Growth Regulation, Institute for Frontier Medical Sciences, Kyoto University, Kyoto, Japan
- * E-mail: (TS); (AS-F)
| | - Hidetoshi Sakurai
- Department of Clinical Application, Center for iPS Cell Research and Application, Kyoto University, Kyoto, Japan
| | - Takuya Yamamoto
- Department of Reprogramming Science, Center for iPS Cell Research and Application, Kyoto University, Kyoto, Japan
| | - Kazunori Hanaoka
- Laboratory of Molecular Embryology, Department of Bioscience, Kitasato University School of Science, Kanagawa, Japan
| | - Didier Montarras
- Molecular Genetics of Development, Institut Pasteur, Paris, France
| | - Atsuko Sehara-Fujisawa
- Department of Growth Regulation, Institute for Frontier Medical Sciences, Kyoto University, Kyoto, Japan
- * E-mail: (TS); (AS-F)
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818
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Davis ME, Gumucio JP, Sugg KB, Bedi A, Mendias CL. MMP inhibition as a potential method to augment the healing of skeletal muscle and tendon extracellular matrix. J Appl Physiol (1985) 2013; 115:884-91. [PMID: 23640595 DOI: 10.1152/japplphysiol.00137.2013] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The extracellular matrix (ECM) of skeletal muscle and tendon is composed of different types of collagen molecules that play important roles in the transmission of forces throughout the body, and in the repair and regeneration of injured tissues. Fibroblasts are the primary cells in muscle and tendon that maintain, repair, and modify the ECM in response to mechanical loading, injury, and inactivity. Matrix metalloproteinases (MMPs) are enzymes that digest collagen and other structural molecules, which are synthesized and excreted by fibroblasts. MMPs are required for baseline ECM homeostasis, but disruption of MMP regulation due to injury or disease can alter the normal ECM architecture and prevent proper force transmission. Chronic injuries and diseases of muscles and tendons can be severely debilitating, and current therapeutic modalities to enhance healing are quite limited. This review will discuss the mechanobiology of MMPs, and the potential use of MMP inhibitors to improve the treatment of injured and diseased skeletal muscle and tendon tissue.
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Affiliation(s)
- Max E Davis
- Department of Orthopaedic Surgery, University of Michigan Medical School, Ann Arbor, Michigan
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819
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Martin NRW, Passey SL, Player DJ, Khodabukus A, Ferguson RA, Sharples AP, Mudera V, Baar K, Lewis MP. Factors affecting the structure and maturation of human tissue engineered skeletal muscle. Biomaterials 2013; 34:5759-65. [PMID: 23643182 DOI: 10.1016/j.biomaterials.2013.04.002] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2013] [Accepted: 04/03/2013] [Indexed: 11/15/2022]
Abstract
Tissue engineered skeletal muscle has great utility in experimental studies of physiology, clinical testing and its potential for transplantation to replace damaged tissue. Despite recent work in rodent tissue or cell lines, there is a paucity of literature concerned with the culture of human muscle derived cells (MDCs) in engineered constructs. Here we aimed to tissue engineer for the first time in the literature human skeletal muscle in self-assembling fibrin hydrogels and determine the effect of MDC seeding density and myogenic proportion on the structure and maturation of the constructs. Constructs seeded with 4 × 10(5) MDCs assembled to a greater extent than those at 1 × 10(5) or 2 × 10(5), and immunostaining revealed a higher fusion index and a higher density of myotubes within the constructs, showing greater structural semblance to in vivo tissue. These constructs primarily expressed perinatal and slow type I myosin heavy chain mRNA after 21 days in culture. In subsequent experiments MACS(®) technology was used to separate myogenic and non-myogenic cells from their heterogeneous parent population and these cells were seeded at varying myogenic (desmin +) proportions in fibrin based constructs. Only in the constructs seeded with 75% desmin + cells was there evidence of striations when immunostained for slow myosin heavy chain compared with constructs seeded with 10 or 50% desmin + cells. Overall, this work reveals the importance of cell number and myogenic proportions in tissue engineering human skeletal muscle with structural resemblance to in vivo tissue.
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Affiliation(s)
- Neil R W Martin
- Musculoskeletal Biology Research Group, School of Sport, Exercise and Health Sciences, Loughborough University, Loughborough, Leicestershire LE113TU, UK
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820
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Biressi S, Bjornson CRR, Carlig PMM, Nishijo K, Keller C, Rando TA. Myf5 expression during fetal myogenesis defines the developmental progenitors of adult satellite cells. Dev Biol 2013; 379:195-207. [PMID: 23639729 DOI: 10.1016/j.ydbio.2013.04.021] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2012] [Revised: 03/21/2013] [Accepted: 04/09/2013] [Indexed: 01/06/2023]
Abstract
Myf5 is a member of the muscle-specific determination genes and plays a critical role in skeletal muscle development. Whereas the expression of Myf5 during embryonic and fetal myogenesis has been extensively studied, its expression in progenitors that will ultimately give rise to adult satellite cells, the stem cells responsible for muscle repair, is still largely unexplored. To investigate this aspect, we have generated a mouse strain carrying a CreER coding sequence in the Myf5 locus. In this strain, Tamoxifen-inducible Cre activity parallels endogenous Myf5 expression. Combining Myf5(CreER) and Cre reporter alleles, we were able to evaluate the contribution of cells expressing Myf5 at distinct developmental stages to the pool of satellite cells in adult hindlimb muscles. Although it was possible to trace back the origin of some rare satellite cells to a subpopulation of Myf5(+ve) progenitors in the limb buds at the late embryonic stage (∼E12), a significant number of satellite cells arise from cells which expressed Myf5 for the first time at the fetal stage (∼E15). These studies provide direct evidence that adult satellite cells derive from progenitors that first express the myogenic determination gene Myf5 during fetal stages of myogenesis.
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Affiliation(s)
- Stefano Biressi
- Paul F. Glenn Laboratories for the Biology of Aging and Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA 94305, USA
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821
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Partridge TA. The mdx mouse model as a surrogate for Duchenne muscular dystrophy. FEBS J 2013; 280:4177-86. [PMID: 23551987 DOI: 10.1111/febs.12267] [Citation(s) in RCA: 135] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2013] [Revised: 03/18/2013] [Accepted: 03/19/2013] [Indexed: 01/06/2023]
Abstract
Research into fundamental principles and the testing of therapeutic hypotheses for treatment of human disease is commonly performed on mouse models of human diseases. Although this is often the only practicable approach, it carries a number of caveats arising from differences between the two species. This review focuses on the example of skeletal muscle disease, in particular muscular dystrophy, to identify some of the principal classes of obstacles to translation of data from mouse to humans. Of these, the difference in scale is one of the most commonly ignored, and is of particular interest because it has quite major repercussions for evaluation of some classes of intervention and of outcome criteria, while having comparatively little bearing on others. Likewise, inter-species differences and similarities in cell and molecular biological mechanisms underlying development, growth and response to pathological processes should be considered on an individual basis. An awareness of such distinctions is crucial if we are to avoid misjudging the likely applicability to humans of results obtained on mouse models.
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Affiliation(s)
- Terence A Partridge
- Children's National Medical Center, Center for Genetic Medicine, Washington, DC 20010, USA.
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822
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Shefer G, Rauner G, Stuelsatz P, Benayahu D, Yablonka-Reuveni Z. Moderate-intensity treadmill running promotes expansion of the satellite cell pool in young and old mice. FEBS J 2013; 280:4063-73. [PMID: 23464362 DOI: 10.1111/febs.12228] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2013] [Revised: 02/13/2013] [Accepted: 02/28/2013] [Indexed: 02/06/2023]
Abstract
Satellite cells, the myogenic progenitors located at the myofibre surface, are essential for the repair of adult skeletal muscle. There is ample evidence for an age-linked decline in the number of satellite cells and performance in limb muscles. Hence, an effective means of activating and expanding the satellite cell pool may enhance muscle maintenance and reduce the impact of age-associated muscle deterioration (sarcopaenia). Accordingly, in the present study, we explored the beneficial effects of endurance exercise on satellite cells in young and old mice. Animals were subjected to an 8-week moderate-intensity treadmill-running approach that does not inflict apparent muscle damage (0° inclination, 11.5 m·min(-1) for 30 min·day(-1) , 6 days·week(-1) ). Myofibres of extensor digitorum longus muscles were then isolated from exercised and sedentary mice and used for monitoring the number of satellite cells, as well as for harvesting individual satellite cells for clonal growth assays. We specifically focused on satellite cell pools of single myofibres, with the view that daily wear of muscles probably affects individual myofibres rather than causing overall muscle damage. We found an expansion of the satellite cell pool in the exercised groups compared to the sedentary groups, with the same increase (~ 1.6-fold) in both ages. The results of the present study are in agreement with our findings obtained using rat gastrocnemius, indicating the consistent effect of exercise on satellite cell expansion in limb muscles. The experimental paradigm established in the present study is useful for investigating satellite cell dynamics at the myofibre niche, as well as for broader investigations of the impact of physiologically and pathologically relevant factors on adult myogenesis.
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Affiliation(s)
- Gabi Shefer
- Department of Cell and Developmental Biology, Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel.
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823
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Carvajal Monroy PL, Grefte S, Kuijpers-Jagtman AM, Helmich MPAC, Ulrich DJO, Von den Hoff JW, Wagener FADTG. A rat model for muscle regeneration in the soft palate. PLoS One 2013; 8:e59193. [PMID: 23554995 PMCID: PMC3598650 DOI: 10.1371/journal.pone.0059193] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2012] [Accepted: 02/12/2013] [Indexed: 11/21/2022] Open
Abstract
Background Children with a cleft in the soft palate have difficulties with speech, swallowing, and sucking. Despite successful surgical repositioning of the muscles, optimal function is often not achieved. Scar formation and defective regeneration may hamper the functional recovery of the muscles after cleft palate repair. Therefore, the aim of this study is to investigate the anatomy and histology of the soft palate in rats, and to establish an in vivo model for muscle regeneration after surgical injury. Methods Fourteen adult male Sprague Dawley rats were divided into four groups. Groups 1 (n = 4) and 2 (n = 2) were used to investigate the anatomy and histology of the soft palate, respectively. Group 3 (n = 6) was used for surgical wounding of the soft palate, and group 4 (n = 2) was used as unwounded control group. The wounds (1 mm) were evaluated by (immuno)histochemistry (AZAN staining, Pax7, MyoD, MyoG, MyHC, and ASMA) after 7 days. Results The present study shows that the anatomy and histology of the soft palate muscles of the rat is largely comparable with that in humans. All wounds showed clinical evidence of healing after 7 days. AZAN staining demonstrated extensive collagen deposition in the wound area, and initial regeneration of muscle fibers and salivary glands. Proliferating and differentiating satellite cells were identified in the wound area by antibody staining. Conclusions This model is the first, suitable for studying muscle regeneration in the rat soft palate, and allows the development of novel adjuvant strategies to promote muscle regeneration after cleft palate surgery.
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Affiliation(s)
- Paola L Carvajal Monroy
- Department of Orthodontics and Craniofacial Biology, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
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824
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Lapin MR, Gonzalez JM, Johnson SE. Substrate elasticity affects bovine satellite cell activation kinetics in vitro. J Anim Sci 2013; 91:2083-90. [PMID: 23463548 DOI: 10.2527/jas.2012-5732] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Satellite cells support efficient postnatal skeletal muscle hypertrophy through fusion into the adjacent muscle fiber. Nuclear contribution allows for maintenance of the fiber myonuclear domain and proficient transcription of myogenic genes. Niche growth factors affect satellite cell biology; however, the interplay between fiber elasticity and microenvironment proteins remains largely unknown. The objective of the experiment was to examine the effects of hepatocyte growth factor (HGF) and surface elasticity on bovine satellite cell (BSC) activation kinetics in vitro. Young's elastic modulus was calculated for the semimembranosus (SM) and LM muscles of young bulls (5 d; n = 8) and adult cows (27 mo; n = 4) cattle. Results indicate that LM elasticity decreased (P < 0.05) with age; no difference in Young's modulus for the SM was noted. Bovine satellite cells were seeded atop polyacrylamide bioscaffolds with surface elasticities that mimic young bull and adult cow LM or traditional cultureware. Cells were maintained in low-serum media supplemented with 5 ng/mL HGF or vehicle only for 24 or 48 h. Activation was evaluated by proliferating cell nuclear antigen (PCNA) immunocytochemistry. Results indicate that BSC maintained on rigid surfaces were activated at 24 h and refractive to HGF supplementation. By contrast, fewer (P < 0.05) BSC had exited quiescence after 24 h of culture on surfaces reflective of either young bull (8.1 ± 1.7 kPa) or adult cow (14.6 ± 1.6 kPa) LM. Supplementation with HGF promoted activation of BSC cultured on bioscaffolds as measured by an increase (P < 0.05) in PCNA immunopositive cells. Culture on pliant surfaces affected neither activation kinetics nor numbers of Paired box 7 (Pax7) immunopositive muscle stem cells (P > 0.05). However, with increasing surface elasticity, an increase (P < 0.05) in the numbers of muscle progenitors was observed. These results confirm that biophysical and biochemical signals regulate BSC activation.
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Affiliation(s)
- M R Lapin
- Department of Animal Sciences, University of Florida, Gainesville, FL 32611, USA
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825
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Lund DK, Cornelison DDW. Enter the matrix: shape, signal and superhighway. FEBS J 2013; 280:4089-99. [PMID: 23374506 DOI: 10.1111/febs.12171] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2013] [Revised: 01/25/2013] [Accepted: 01/28/2013] [Indexed: 12/20/2022]
Abstract
Mammalian skeletal muscle is notable for both its highly ordered biophysical structure and its regenerative capacity following trauma. Critical to both of these features is the specialized muscle extracellular matrix, comprising both the multiple concentric sheaths of connective tissue surrounding structural units from single myofibers to whole muscles and the dense interstitial matrix that occupies the space between them. Extracellular matrix-dependent interactions affect all activities of the resident muscle stem cell population (the satellite cells), from maintenance of quiescence and stem cell potential to the regulation of proliferation and differentiation. This review focuses on the role of the extracellular matrix in muscle regeneration, with a particular emphasis on regulation of satellite-cell activity.
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Affiliation(s)
- Dane K Lund
- Division of Biological Sciences, University of Missouri, Columbia, MO 65211, USA
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826
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Improved tissue culture conditions for engineered skeletal muscle sheets. ScientificWorldJournal 2013; 2013:370151. [PMID: 23533347 PMCID: PMC3603544 DOI: 10.1155/2013/370151] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2012] [Accepted: 01/24/2013] [Indexed: 12/22/2022] Open
Abstract
The potential clinical utility of engineered muscle is currently restricted by limited in vitro capacity of expanded muscle precursor cells to fuse and form mature myofibers. The purpose of this study was to use isotropic skeletal muscle sheets to explore the impact of (1) fibroblast coculture and (2) fibroblast-conditioned media (fCM) on in vitro myogenesis. Muscle sheets were prepared by seeding varying ratios of skeletal myoblasts and fibroblasts on a biomimetic substrate and culturing the resulting tissue in either control media or fCM. Muscle sheets were prepared from two cell subpopulations, (1) C2C12 and NOR-10 and (2) primary neonatal rat skeletal muscle cells (nSKM). In C2C12/Nor-10 muscle sheets fCM conferred a myogenic advantage early in culture; at D1 a statistically significant 3.12 ± 0.8-fold increase in myofiber density was observed with fCM. A high purity satellite cell population was collected from an initially mixed population of nSKMs via cell sorting for positive α 7-integrin expression. On D6, tissue sheets with low fibroblast concentrations (0 & 10%) cultured in fCM had increased average myofiber density (4.8 ± 0.2 myofibers/field) compared to tissue sheets with high fibroblast concentrations (50%) cultured in control media (1.0 ± 0.1 myofibers/field). Additionally, fCM promoted longer, thicker myofibers with a mature phenotype.
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827
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Abstract
Adult skeletal muscle in mammals is a stable tissue under normal circumstances but has remarkable ability to repair after injury. Skeletal muscle regeneration is a highly orchestrated process involving the activation of various cellular and molecular responses. As skeletal muscle stem cells, satellite cells play an indispensible role in this process. The self-renewing proliferation of satellite cells not only maintains the stem cell population but also provides numerous myogenic cells, which proliferate, differentiate, fuse, and lead to new myofiber formation and reconstitution of a functional contractile apparatus. The complex behavior of satellite cells during skeletal muscle regeneration is tightly regulated through the dynamic interplay between intrinsic factors within satellite cells and extrinsic factors constituting the muscle stem cell niche/microenvironment. For the last half century, the advance of molecular biology, cell biology, and genetics has greatly improved our understanding of skeletal muscle biology. Here, we review some recent advances, with focuses on functions of satellite cells and their niche during the process of skeletal muscle regeneration.
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Affiliation(s)
- Hang Yin
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada
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828
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Straessler KM, Jones KB, Hu H, Jin H, van de Rijn M, Capecchi MR. Modeling clear cell sarcomagenesis in the mouse: cell of origin differentiation state impacts tumor characteristics. Cancer Cell 2013; 23:215-27. [PMID: 23410975 PMCID: PMC3640275 DOI: 10.1016/j.ccr.2012.12.019] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/20/2012] [Revised: 11/13/2012] [Accepted: 12/26/2012] [Indexed: 01/18/2023]
Abstract
Clear cell sarcoma (CCS) of tendons and aponeuroses is a deadly soft-tissue malignancy resembling melanoma, with a predilection for young adults. EWS-ATF1, the fusion product of a balanced chromosomal translocation between chromosomes 22 and 12, is considered the definitional feature of the tumor. Conditional expression of the EWS-ATF1 human cDNA in the mouse generates CCS-like tumors with 100% penetrance. Tumors, developed through varied means of initiating expression of the fusion oncogene, model human CCS morphologically, immunohistochemically, and by genome-wide expression profiling. We also demonstrate that although fusion oncogene expression in later stages of differentiation can transform mesenchymal progenitor cells and generate tumors resembling CCS generally, expression in cells retaining stem cell markers permits the full melanoma-related phenotype.
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Affiliation(s)
- Krystal M. Straessler
- Department of Human Genetics, University of Utah School of Medicine, Salt Lake City, UT 84112, USA
| | - Kevin B. Jones
- Department of Orthopaedics and Huntsman Cancer Institute Center for Children's Cancer Research, University of Utah School of Medicine, Salt Lake City, UT 84112, USA
| | - Hao Hu
- Department of Epidemiology, The University of Texas M.D. Anderson Cancer Center, Houston, TX 77030, USA
| | - Huifeng Jin
- Department of Orthopaedics and Huntsman Cancer Institute Center for Children's Cancer Research, University of Utah School of Medicine, Salt Lake City, UT 84112, USA
| | - Matt van de Rijn
- Department of Pathology, Stanford University Medical Center, Palo Alto, CA 94305
| | - Mario R. Capecchi
- Department of Human Genetics, University of Utah School of Medicine, Salt Lake City, UT 84112, USA
- Howard Hughes Medical Institute, University of Utah School of Medicine, Salt Lake City, UT 84112, USA
- Correspondence: , 801.581.7096
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829
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Le Grand F, Grifone R, Mourikis P, Houbron C, Gigaud C, Pujol J, Maillet M, Pagès G, Rudnicki M, Tajbakhsh S, Maire P. Six1 regulates stem cell repair potential and self-renewal during skeletal muscle regeneration. ACTA ACUST UNITED AC 2013; 198:815-32. [PMID: 22945933 PMCID: PMC3432771 DOI: 10.1083/jcb.201201050] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Six1 in satellite cells is important for muscle regeneration and homeostasis of the stem cell niche by regulating MyoD, Myogenin, and Dusp6-ERK signaling. Satellite cells (SCs) are stem cells that mediate skeletal muscle growth and regeneration. Here, we observe that adult quiescent SCs and their activated descendants expressed the homeodomain transcription factor Six1. Genetic disruption of Six1 specifically in adult SCs impaired myogenic cell differentiation, impaired myofiber repair during regeneration, and perturbed homeostasis of the stem cell niche, as indicated by an increase in SC self-renewal. Six1 regulated the expression of the myogenic regulatory factors MyoD and Myogenin, but not Myf5, which suggests that Six1 acts on divergent genetic networks in the embryo and in the adult. Moreover, we demonstrate that Six1 regulates the extracellular signal-regulated kinase 1/2 (ERK1/2) pathway during regeneration via direct control of Dusp6 transcription. Muscles lacking Dusp6 were able to regenerate properly but showed a marked increase in SC number after regeneration. We conclude that Six1 homeoproteins act as a rheostat system to ensure proper regeneration of the tissue and replenishment of the stem cell pool during the events that follow skeletal muscle trauma.
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Affiliation(s)
- Fabien Le Grand
- Institut National de la Santé et de la Recherche Médicale U1016, Institut Cochin, Paris 75014, France.
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830
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Hyldahl RD, Schwartz LM, Clarkson PM. NF-KB activity functions in primary pericytes in a cell- and non-cell-autonomous manner to affect myotube formation. Muscle Nerve 2013; 47:522-31. [PMID: 23364895 DOI: 10.1002/mus.23640] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/19/2012] [Indexed: 12/23/2022]
Abstract
INTRODUCTION Skeletal muscle regeneration following damage relies on proliferation and differentiation of muscle precursor cells (MPCs). We recently observed increased NF-kB activity in vascular-associated muscle resident pericytes following muscle damage in humans. We determined how altered NF-kB activity in human primary pericytes (HPPs) affects their myogenic differentiation (cell-autonomous effects), as well as proliferation and differentiation of co-cultured MPCs (non-cell-autonomous effects). METHODS HPPs were transfected with vectors that increased or decreased NF-kB activity. Transfected HPPs were co-cultured with C2 C12 myoblasts under differentiation conditions, and HPP fusion to myotubes was measured. We also co-cultured HPPs with C2 C12 myoblasts and measured proliferation and myotube formation. RESULTS Inhibition of NF-kB activity increased HPP fusion to C2 C12 myotubes. Moreover, enhanced NF-kB activity in HPPs suppressed differentiation and enhanced proliferation of co-cultured myoblasts. CONCLUSIONS NF-kB activity acts cell-autonomously to inhibit HPP myogenic differentiation and non-cell-autonomously to promote MPC proliferation and suppress MPC differentiation in vitro.
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Affiliation(s)
- Robert D Hyldahl
- Department of Kinesiology, University of Massachusetts Amherst, 300 Massachusetts Avenue, Amherst, Massachusetts 01003, USA.
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831
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Macrophage plasticity and the role of inflammation in skeletal muscle repair. Mediators Inflamm 2013; 2013:491497. [PMID: 23509419 PMCID: PMC3572642 DOI: 10.1155/2013/491497] [Citation(s) in RCA: 218] [Impact Index Per Article: 18.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2012] [Accepted: 01/03/2013] [Indexed: 12/24/2022] Open
Abstract
Effective repair of damaged tissues and organs requires the coordinated action of several cell types, including infiltrating inflammatory cells and resident cells. Recent findings have uncovered a central role for macrophages in the repair of skeletal muscle after acute damage. If damage persists, as in skeletal muscle pathologies such as Duchenne muscular dystrophy (DMD), macrophage infiltration perpetuates and leads to progressive fibrosis, thus exacerbating disease severity. Here we discuss how dynamic changes in macrophage populations and activation states in the damaged muscle tissue contribute to its efficient regeneration. We describe how ordered changes in macrophage polarization, from M1 to M2 subtypes, can differently affect muscle stem cell (satellite cell) functions. Finally, we also highlight some of the new mechanisms underlying macrophage plasticity and briefly discuss the emerging implications of lymphocytes and other inflammatory cell types in normal versus pathological muscle repair.
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832
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Boldrin L, Morgan JE. Grafting of a single donor myofibre promotes hypertrophy in dystrophic mouse muscle. PLoS One 2013; 8:e54599. [PMID: 23349935 PMCID: PMC3548842 DOI: 10.1371/journal.pone.0054599] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2012] [Accepted: 12/13/2012] [Indexed: 12/02/2022] Open
Abstract
Skeletal muscle has a remarkable capability of regeneration following injury. Satellite cells, the principal muscle stem cells, are responsible for this process. However, this regenerative capacity is reduced in muscular dystrophies or in old age: in both these situations, there is a net loss of muscle fibres. Promoting skeletal muscle muscle hypertrophy could therefore have potential applications for treating muscular dystrophies or sarcopenia. Here, we observed that muscles of dystrophic mdx nude host mice that had been acutely injured by myotoxin and grafted with a single myofibre derived from a normal donor mouse exhibited increased muscle area. Transplantation experiments revealed that the hypertrophic effect is mediated by the grafted fibre and does not require either an imposed injury to the host muscle, or the contribution of donor cells to the host muscle. These results suggest the presence of a crucial cross-talk between the donor fibre and the host muscle environment.
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MESH Headings
- Age Factors
- Animals
- Crotalid Venoms/toxicity
- Hypertrophy
- Mice
- Mice, Inbred mdx
- Mice, Nude
- Muscle, Skeletal/cytology
- Muscle, Skeletal/injuries
- Muscle, Skeletal/transplantation
- Muscular Dystrophy, Animal/chemically induced
- Muscular Dystrophy, Animal/genetics
- Muscular Dystrophy, Animal/physiopathology
- Muscular Dystrophy, Animal/therapy
- Regeneration/genetics
- Regeneration/physiology
- Satellite Cells, Skeletal Muscle/cytology
- Satellite Cells, Skeletal Muscle/transplantation
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Affiliation(s)
- Luisa Boldrin
- The Dubowitz Neuromuscular Centre, UCL Institute of Child Health, London, United Kingdom.
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833
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Boldrin L, Neal A, Zammit PS, Muntoni F, Morgan JE. Donor satellite cell engraftment is significantly augmented when the host niche is preserved and endogenous satellite cells are incapacitated. Stem Cells 2013; 30:1971-84. [PMID: 22730231 PMCID: PMC3465801 DOI: 10.1002/stem.1158] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Stem cell transplantation is already in clinical practice for certain genetic diseases and is a promising therapy for dystrophic muscle. We used the mdx mouse model of Duchenne muscular dystrophy to investigate the effect of the host satellite cell niche on the contribution of donor muscle stem cells (satellite cells) to muscle regeneration. We found that incapacitation of the host satellite cells and preservation of the muscle niche promote donor satellite cell contribution to muscle regeneration and functional reconstitution of the satellite cell compartment. But, if the host niche is not promptly refilled, or is filled by competent host satellite cells, it becomes nonfunctional and donor engraftment is negligible. Application of this regimen to aged host muscles also promotes efficient regeneration from aged donor satellite cells. In contrast, if the niche is destroyed, yet host satellite cells remain proliferation-competent, donor-derived engraftment is trivial. Thus preservation of the satellite cell niche, concomitant with functional impairment of the majority of satellite cells within dystrophic human muscles, may improve the efficiency of stem cell therapy.
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Affiliation(s)
- Luisa Boldrin
- The Dubowitz Neuromuscular Centre, UCL Institute of Child Health, London, United Kingdom.
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834
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Penton CM, Thomas-Ahner JM, Johnson EK, McAllister C, Montanaro F. Muscle side population cells from dystrophic or injured muscle adopt a fibro-adipogenic fate. PLoS One 2013; 8:e54553. [PMID: 23336007 PMCID: PMC3545954 DOI: 10.1371/journal.pone.0054553] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2012] [Accepted: 12/14/2012] [Indexed: 11/17/2022] Open
Abstract
Muscle side population (SP) cells are rare multipotent stem cells that can participate in myogenesis and muscle regeneration upon transplantation. While they have been primarily studied for the development of cell-based therapies for Duchenne muscular dystrophy, little is known regarding their non-muscle lineage choices or whether the dystrophic muscle environment affects their ability to repair muscle. Unfortunately, the study of muscle SP cells has been challenged by their low abundance and the absence of specific SP cell markers. To address these issues, we developed culture conditions for the propagation and spontaneous multi-lineage differentiation of muscle SP cells. Using this approach, we show that SP cells from wild type muscle robustly differentiate into satellite cells and form myotubes without requiring co-culture with myogenic cells. Furthermore, this myogenic activity is associated with SP cells negative for immune (CD45) and vascular (CD31) markers but positive for Pax7, Sca1, and the mesenchymal progenitor marker PDGFRα. Additionally, our studies revealed that SP cells isolated from dystrophic or cardiotoxin-injured muscle fail to undergo myogenesis. Instead, these SP cells rapidly expand giving rise to fibroblast and adipocyte progenitors (FAPs) and to their differentiated progeny, fibroblasts and adipocytes. Our findings indicate that muscle damage affects the lineage choices of muscle SP cells, promoting their differentiation along fibro-adipogenic lineages while inhibiting myogenesis. These results have implications for a possible role of muscle SP cells in fibrosis and fat deposition in muscular dystrophy. In addition, our studies provide a useful in vitro system to analyze SP cell biology in both normal and pathological conditions.
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Affiliation(s)
- Christopher M Penton
- Center for Gene Therapy, The Research Institute at Nationwide Children's Hospital, Columbus, Ohio, USA
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835
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Xynos A, Neguembor MV, Caccia R, Licastro D, Nonis A, Di Serio C, Stupka E, Gabellini D. Facioscapulohumeral muscular dystrophy region gene 1 over-expression causes primary defects of myogenic stem cells. J Cell Sci 2013; 126:2236-45. [DOI: 10.1242/jcs.121533] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Over-expression of FSHD Region Gene 1 (FRG1) in mice, frogs and worms leads to muscular and vascular abnormalities. Nevertheless, the mechanism that follows FRG1 over-expression and finally leads to muscular defects is currently unknown. Here, we show that the earliest phenotype displayed by FRG1 mice is a postnatal muscle-growth defect. Long before the development of muscular dystrophy, FRG1 mice exhibit also a muscle regeneration impairment. Ex-vivo and in-vivo experiments revealed that FRG1 over-expression causes myogenic stem-cell activation, proliferative, clonogenic and differentiation defects. A comparative gene expression profiling of WT and FRG1 muscles from young pre-dystrophic mice identified differentially expressed genes in several gene categories and networks that could explain the emerging tissue and myogenic stem-cell defects. Overall, our study provides new insights in the pathways regulated by FRG1 and suggests that muscle-stem cells defects could contribute to the pathology of FRG1 mice.
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836
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Markworth JF, Cameron-Smith D. Arachidonic acid supplementation enhances in vitro skeletal muscle cell growth via a COX-2-dependent pathway. Am J Physiol Cell Physiol 2013; 304:C56-67. [DOI: 10.1152/ajpcell.00038.2012] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Arachidonic acid (AA) is the metabolic precursor to a diverse range of downstream bioactive lipid mediators. A positive or negative influence of individual eicosanoid species [e.g., prostaglandins (PGs), leukotrienes, and hydroxyeicosatetraenoic acids] has been implicated in skeletal muscle cell growth and development. The collective role of AA-derived metabolites in physiological states of skeletal muscle growth/atrophy remains unclear. The present study aimed to determine the direct effect of free AA supplementation and subsequent eicosanoid biosynthesis on skeletal myocyte growth in vitro . C2C12 (mouse) skeletal myocytes induced to differentiate with supplemental AA exhibited dose-dependent increases in the size, myonuclear content, and protein accretion of developing myotubes, independent of changes in cell density or the rate/extent of myogenic differentiation. Nonselective (indomethacin) or cyclooxygenase 2 (COX-2)-selective (NS-398) nonsteroidal anti-inflammatory drugs blunted basal myogenesis, an effect that was amplified in the presence of supplemental free AA substrate. The stimulatory effects of AA persisted in preexisting myotubes via a COX-2-dependent (NS-389-sensitive) pathway, specifically implying dependency on downstream PG biosynthesis. AA-stimulated growth was associated with markedly increased secretion of PGF2α and PGE2; however, incubation of myocytes with PG-rich conditioned medium failed to mimic the effects of direct AA supplementation. In vitro AA supplementation stimulates PG release and skeletal muscle cell hypertrophy via a COX-2-dependent pathway.
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Affiliation(s)
- James F. Markworth
- School of Exercise and Nutrition Science, Deakin University, Melbourne, Australia; and
- Liggins Institute, University of Auckland, Auckland, New Zealand
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837
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Resident mesenchymal cells and fibrosis. Biochim Biophys Acta Mol Basis Dis 2012; 1832:962-71. [PMID: 23220259 DOI: 10.1016/j.bbadis.2012.11.015] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2012] [Revised: 11/15/2012] [Accepted: 11/17/2012] [Indexed: 02/07/2023]
Abstract
Fibrosis is a major clinical problem associated with as many as 45% of all natural deaths in developed nations. It can affect all organs and accumulating evidence indicates that fibrogenesis is not merely a bystander product of injury, but is a central pathological problem directly contributing to loss of organ function. In the majority of clinical cases, fibrogenesis is strongly associated with the recruitment of leukocytes, even in the absence of infection. Although chronic infections are a significant cause of fibrogenesis, in most cases fibrotic disease occurs in the context of sterile injury, such as microvascular disease, toxic epithelial injury or diabetes mellitus. Fibrogenesis is a direct consequence of the activation of extensive, and previously poorly appreciated, populations of mesenchymal cells in our organs which are either wrapped around capillaries and known as 'pericytes', or embedded in interstitial spaces between cell structures and known as resident 'fibroblasts'. Recent fate-mapping and complementary studies in several organs indicate that these cells are the precursors of the scar-forming myofibroblasts that appear in our organs in response to injury. Here we will review the literature supporting a central role for these cells in fibrogenesis, and highlight some of the critical cell to cell interactions that are necessary for the initiation and continuation of the fibrogenic process. This article is part of a Special Issue entitled: Fibrosis: Translation of basic research to human disease.
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838
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Woodhouse S, Pugazhendhi D, Brien P, Pell JM. Ezh2 maintains a key phase of muscle satellite cell expansion but does not regulate terminal differentiation. J Cell Sci 2012. [PMID: 23203812 DOI: 10.1242/jcs.114843] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Tissue generation and repair requires a stepwise process of cell fate restriction to ensure that adult stem cells differentiate in a timely and appropriate manner. A crucial role has been implicated for Polycomb-group (PcG) proteins and the H3K27me3 repressive histone mark in coordinating the transcriptional programmes necessary for this process, but the targets and developmental timing for this repression remain unclear. To address these questions, we generated novel genome-wide maps of H3K27me3 and H3K4me3 in freshly isolated muscle stem cells. These data, together with the analysis of two conditional Ezh2-null mouse strains, identified a critical proliferation phase in which Ezh2 activity is essential. Mice lacking Ezh2 in satellite cells exhibited decreased muscle growth, severely impaired regeneration and reduced stem cell number, due to a profound failure of the proliferative progenitor population to expand. Surprisingly, deletion of Ezh2 after the onset of terminal differentiation did not impede muscle repair or homeostasis. Using these knockout models and the RNA-Seq and ChIP-Seq datasets, we show that Ezh2 does not regulate the muscle differentiation process in vivo. These results emphasise the lineage and cell-type-specific functions of Ezh2 and Polycomb repressive complex 2.
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839
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Duffield JS, Lupher M, Thannickal VJ, Wynn TA. Host responses in tissue repair and fibrosis. ANNUAL REVIEW OF PATHOLOGY-MECHANISMS OF DISEASE 2012; 8:241-76. [PMID: 23092186 DOI: 10.1146/annurev-pathol-020712-163930] [Citation(s) in RCA: 466] [Impact Index Per Article: 35.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Myofibroblasts accumulate in the spaces between organ structures and produce extracellular matrix (ECM) proteins, including collagen I. They are the primary "effector" cells in tissue remodeling and fibrosis. Previously, leukocyte progenitors termed fibrocytes and myofibroblasts generated from epithelial cells through epithelial-to-mesenchymal transition (EMT) were considered the primary sources of ECM-producing myofibroblasts in injured tissues. However, genetic fate mapping experiments suggest that mesenchyme-derived cells, known as resident fibroblasts, and pericytes are the primary precursors of scar-forming myofibroblasts, whereas epithelial cells, endothelial cells, and myeloid leukocytes contribute to fibrogenesis predominantly by producing key fibrogenic cytokines and by promoting cell-to-cell communication. Numerous cytokines derived from T cells, macrophages, and other myeloid cell populations are important drivers of myofibroblast differentiation. Monocyte-derived cell populations are key regulators of the fibrotic process: They act as a brake on the processes driving fibrogenesis, and they dismantle and degrade established fibrosis. We discuss the origins, modes of activation, and fate of myofibroblasts in various important fibrotic diseases and describe how manipulation of macrophage activation could help ameliorate fibrosis.
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Affiliation(s)
- Jeremy S Duffield
- Division of Nephrology, Center for Lung Biology, and the Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA 98019, USA
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840
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Relaix F, Zammit PS. Satellite cells are essential for skeletal muscle regeneration: the cell on the edge returns centre stage. Development 2012; 139:2845-56. [PMID: 22833472 DOI: 10.1242/dev.069088] [Citation(s) in RCA: 598] [Impact Index Per Article: 46.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Following their discovery in 1961, it was speculated that satellite cells were dormant myoblasts, held in reserve until required for skeletal muscle repair. Evidence for this accumulated over the years, until the link between satellite cells and the myoblasts that appear during muscle regeneration was finally established. Subsequently, it was demonstrated that, when grafted, satellite cells could also self-renew, conferring on them the coveted status of 'stem cell'. The emergence of other cell types with myogenic potential, however, questioned the precise role of satellite cells. Here, we review recent recombination-based studies that have furthered our understanding of satellite cell biology. The clear consensus is that skeletal muscle does not regenerate without satellite cells, confirming their pivotal and non-redundant role.
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841
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Farina NH, Hausburg M, Betta ND, Pulliam C, Srivastava D, Cornelison D, Olwin BB. A role for RNA post-transcriptional regulation in satellite cell activation. Skelet Muscle 2012; 2:21. [PMID: 23046558 PMCID: PMC3563611 DOI: 10.1186/2044-5040-2-21] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2012] [Accepted: 08/15/2012] [Indexed: 12/18/2022] Open
Abstract
Background Satellite cells are resident skeletal muscle stem cells responsible for muscle maintenance and repair. In resting muscle, satellite cells are maintained in a quiescent state. Satellite cell activation induces the myogenic commitment factor, MyoD, and cell cycle entry to facilitate transition to a population of proliferating myoblasts that eventually exit the cycle and regenerate muscle tissue. The molecular mechanism involved in the transition of a quiescent satellite cell to a transit-amplifying myoblast is poorly understood. Methods Satellite cells isolated by FACS from uninjured skeletal muscle and 12 h post-muscle injury from wild type and Syndecan-4 null mice were probed using Affymetrix 430v2 gene chips and analyzed by Spotfiretm and Ingenuity Pathway analysis to identify gene expression changes and networks associated with satellite cell activation, respectively. Additional analyses of target genes identify miRNAs exhibiting dynamic changes in expression during satellite cell activation. The function of the miRNAs was assessed using miRIDIAN hairpin inhibitors. Results An unbiased gene expression screen identified over 4,000 genes differentially expressed in satellite cells in vivo within 12 h following muscle damage and more than 50% of these decrease dramatically. RNA binding proteins and genes involved in post-transcriptional regulation were significantly over-represented whereas splicing factors were preferentially downregulated and mRNA stability genes preferentially upregulated. Furthermore, six computationally identified miRNAs demonstrated novel expression through muscle regeneration and in satellite cells. Three of the six miRNAs were found to regulate satellite cell fate. Conclusions The quiescent satellite cell is actively maintained in a state poised to activate in response to external signals. Satellite cell activation appears to be regulated by post-transcriptional gene regulation.
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Affiliation(s)
- Nicholas H Farina
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, CO, 80309, USA.
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842
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Díaz-Manera J, Gallardo E, de Luna N, Navas M, Soria L, Garibaldi M, Rojas-García R, Tonlorenzi R, Cossu G, Illa I. The increase of pericyte population in human neuromuscular disorders supports their role in muscle regeneration in vivo. J Pathol 2012; 228:544-53. [PMID: 22847756 DOI: 10.1002/path.4083] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2012] [Revised: 07/08/2012] [Accepted: 07/25/2012] [Indexed: 12/24/2022]
Abstract
Pericytes are periendothelial cells that have been involved in many different functions including a possible role as mesodermal stem/progenitor cells. In the present study we demonstrate that alkaline phosphatase (AP) expression is specific for human muscular pericytes and can be used as a marker to identify them in skeletal muscle biopsies. We studied the pericyte population in skeletal muscle biopsies from controls, myopathic and neuropathic patients. We observed a significant increase in the number of pericytes only in myopathies that correlated with the number of NCAM(+) fibres, suggesting that an active muscular degenerative/regenerative process is related to an increase in the pericyte population. AP(+) pericytes sorted from skeletal muscle samples were able to activate the myogenic programme and fuse with both mononucleate satellite cells and mature multinucleated myotubes in vitro, demonstrating that they could participate in muscle regeneration. In accordance, pericytes expressing the myogenic transcription factor MyoD were found in biopsies of myopathic biopsies. All these data support the hypothesis that, apart from satellite cells, pericytes may play an important role in muscle regeneration in adult human muscles in vivo.
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Affiliation(s)
- Jordi Díaz-Manera
- Neuromuscular Disorders Unit, Neurology Department, Universitat Autònoma de Barcelona, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain; Centro de Investigación Biomédica en Red en Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
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843
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Ross J, Benn A, Jonuschies J, Boldrin L, Muntoni F, Hewitt JE, Brown SC, Morgan JE. Defects in glycosylation impair satellite stem cell function and niche composition in the muscles of the dystrophic Large(myd) mouse. Stem Cells 2012; 30:2330-41. [PMID: 22887880 PMCID: PMC3532609 DOI: 10.1002/stem.1197] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2012] [Revised: 06/08/2012] [Accepted: 06/22/2012] [Indexed: 12/20/2022]
Abstract
The dystrophin-associated glycoprotein complex (DGC) is found at the muscle fiber sarcolemma and forms an essential structural link between the basal lamina and internal cytoskeleton. In a set of muscular dystrophies known as the dystroglycanopathies, hypoglycosylation of the DGC component α-dystroglycan results in reduced binding to basal lamina components, a loss in structural stability, and repeated cycles of muscle fiber degeneration and regeneration. The satellite cells are the key stem cells responsible for muscle repair and reside between the basal lamina and sarcolemma. In this study, we aimed to determine whether pathological changes associated with the dystroglycanopathies affect satellite cell function. In the Large(myd) mouse dystroglycanopathy model, satellite cells are present in significantly greater numbers but display reduced proliferation on their native muscle fibers in vitro, compared with wild type. However, when removed from their fiber, proliferation in culture is restored to that of wild type. Immunohistochemical analysis of Large(myd) muscle reveals alterations to the basal lamina and interstitium, including marked disorganization of laminin, upregulation of fibronectin and collagens. Proliferation and differentiation of wild-type satellite cells is impaired when cultured on substrates such as collagen and fibronectin, compared with laminins. When engrafted into irradiated tibialis anterior muscles of mdx-nude mice, wild-type satellite cells expanded on laminin contribute significantly more to muscle regeneration than those expanded on fibronectin. These results suggest that defects in α-dystroglycan glycosylation are associated with an alteration in the satellite cell niche, and that regenerative potential in the dystroglycanopathies may be perturbed.
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Affiliation(s)
- Jacob Ross
- Dubowitz Neuromuscular Centre, Institute of Child Health, University College London, London, UK
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844
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Abstract
PURPOSE OF REVIEW This review focuses on stem cell-based therapies to treat skeletal muscle disorders, with a special emphasis on muscular dystrophies. RECENT FINDINGS We briefly review previous attempts at cell therapy by the use of donor myoblasts, explaining the likely reasons for the poor clinical results; we then describe the use of the same cells in current promising trials for localized treatments of different diseases of skeletal muscle. Moreover, we discuss important novel findings on muscle stem/progenitor cell biology and their promise for future clinical translation. Preclinical and clinical applications of novel myogenic stem/progenitor cells are also described. SUMMARY We summarize several ongoing clinical trials for different muscle disorders and the advances in the understanding of the biology of the myogenic progenitors used in such trials. On the basis of the currently available information, a prediction of developments in the field is proposed.
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Affiliation(s)
- Francesco S Tedesco
- Department of Cell and Developmental Biology and Centre for Stem Cells and Regenerative Medicine, University College London, London, UK
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845
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Abstract
The niche is a conserved regulator of stem cell quiescence and function. During aging, stem cell function declines. To what extent and by which means age-related changes within the niche contribute to this phenomenon are unknown. We demonstrate that the aged muscle stem cell niche, the muscle fiber, expresses FGF2 under homeostatic conditions, driving a subset of satellite cells to break quiescence and lose self-renewing capacity. We show that relatively dormant aged satellite cells robustly express Sprouty1 (spry1), an inhibitor of FGF signalling. Increasing FGF signalling in aged satellite cells under homeostatic conditions by removing spry1, results in the loss of quiescence, satellite cell depletion and diminished regenerative capacity. Conversely, reducing niche-derived FGF activity through inhibition of FGFR1 signalling or overexpression of spry1 in satellite cells prevents their depletion. These experiments identify an age-dependent change in the stem cell niche that directly influences stem cell quiescence and function.
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846
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Abstract
Satellite cells represent the primary population of stem cells resident in skeletal muscle. These adult muscle stem cells facilitate the postnatal growth, remodeling, and regeneration of skeletal muscle. Given the remarkable regenerative potential of satellite cells, there is great promise for treatment of muscle pathologies such as the muscular dystrophies with this cell population. Various protocols have been developed which allow for isolation, enrichment, and expansion of satellite cell derived muscle stem cells. However, isolated satellite cells have yet to translate into effective modalities for therapeutic intervention. Broadening our understanding of satellite cells and their niche requirements should improve our in vivo and ex vivo manipulation of these cells to expedite their use for regeneration of diseased muscle. This review explores the fates of satellite cells as determined by their molecular signatures, ontogeny, and niche dependent programming.
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Affiliation(s)
- Arif Aziz
- Sprott Center for Stem Cell Research, Regenerative Medicine Program, Ottawa Hospital Research Institute, 501 Smyth Rd, Mailbox 511, Ottawa, ON, Canada K1H 8L6
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847
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Abstract
In 1961, the satellite cell was first identified when electron microscopic examination of skeletal muscle demonstrated a cell wedged between the plasma membrane of the muscle fiber and the basement membrane. In recent years it has been conclusively demonstrated that the satellite cell is the primary cellular source for muscle regeneration and is equipped with the potential to self renew, thus functioning as a bona fide skeletal muscle stem cell (MuSC). As we move past the 50(th) anniversary of the satellite cell, we take this opportunity to discuss the current state of the art and dissect the unknowns in the MuSC field.
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848
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Short-term calorie restriction enhances skeletal muscle stem cell function. Cell Stem Cell 2012; 10:515-9. [PMID: 22560075 DOI: 10.1016/j.stem.2012.04.002] [Citation(s) in RCA: 286] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2011] [Revised: 01/26/2012] [Accepted: 04/03/2012] [Indexed: 01/13/2023]
Abstract
Calorie restriction (CR) extends life span and ameliorates age-related pathologies in most species studied, yet the mechanisms underlying these effects remain unclear. Using mouse skeletal muscle as a model, we show that CR acts in part by enhancing the function of tissue-specific stem cells. Even short-term CR significantly enhanced stem cell availability and activity in the muscle of young and old animals, in concert with an increase in mitochondrial abundance and induction of conserved metabolic and longevity regulators. Moreover, CR enhanced endogenous muscle repair and CR initiated in either donor or recipient animals improved the contribution of donor cells to regenerating muscle after transplant. These studies indicate that metabolic factors play a critical role in regulating stem cell function and that this regulation can influence the efficacy of recovery from injury and the engraftment of transplanted cells.
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849
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Jackson JR, Mula J, Kirby TJ, Fry CS, Lee JD, Ubele MF, Campbell KS, McCarthy JJ, Peterson CA, Dupont-Versteegden EE. Satellite cell depletion does not inhibit adult skeletal muscle regrowth following unloading-induced atrophy. Am J Physiol Cell Physiol 2012; 303:C854-61. [PMID: 22895262 DOI: 10.1152/ajpcell.00207.2012] [Citation(s) in RCA: 112] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Resident muscle stem cells, known as satellite cells, are thought to be the main mediators of skeletal muscle plasticity. Satellite cells are activated, replicate, and fuse into existing muscle fibers in response to both muscle injury and mechanical load. It is generally well-accepted that satellite cells participate in postnatal growth, hypertrophy, and muscle regeneration following injury; however, their role in muscle regrowth following an atrophic stimulus remains equivocal. The current study employed a genetic mouse model (Pax7-DTA) that allowed for the effective depletion of >90% of satellite cells in adult muscle upon the administration of tamoxifen. Vehicle and tamoxifen-treated young adult female mice were either hindlimb suspended for 14 days to induce muscle atrophy or hindlimb suspended for 14 days followed by 14 days of reloading to allow regrowth, or they remained ambulatory for the duration of the experimental protocol. Additionally, 5-bromo-2'-deoxyuridine (BrdU) was added to the drinking water to track cell proliferation. Soleus muscle atrophy, as measured by whole muscle wet weight, fiber cross-sectional area, and single-fiber width, occurred in response to suspension and did not differ between satellite cell-depleted and control muscles. Furthermore, the depletion of satellite cells did not attenuate muscle mass or force recovery during the 14-day reloading period, suggesting that satellite cells are not required for muscle regrowth. Myonuclear number was not altered during either the suspension or the reloading period in soleus muscle fibers from vehicle-treated or satellite cell-depleted animals. Thus, myonuclear domain size was reduced following suspension due to decreased cytoplasmic volume and was completely restored following reloading, independent of the presence of satellite cells. These results provide convincing evidence that satellite cells are not required for muscle regrowth following atrophy and that, instead, the myonuclear domain size changes as myofibers adapt.
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Affiliation(s)
- Janna R Jackson
- Department of Rehabilitation Sciences, College of Health Sciences, University of Kentucky, Lexington, 40536-0200, USA
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850
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Pannérec A, Marazzi G, Sassoon D. Stem cells in the hood: the skeletal muscle niche. Trends Mol Med 2012; 18:599-606. [PMID: 22877884 DOI: 10.1016/j.molmed.2012.07.004] [Citation(s) in RCA: 94] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2012] [Revised: 07/04/2012] [Accepted: 07/11/2012] [Indexed: 12/14/2022]
Abstract
It is generally accepted that the principal resident progenitor underlying regenerative capacity in skeletal muscle is the satellite cell. Satellite cells are present throughout life even though regenerative capacity declines with age and disease. Recently, other stem cell populations have been identified that can participate in muscle growth and regeneration. These cells may provide therapeutically useful sources of muscle stem cells as an alternative to satellite cells; however, the roles of these nonsatellite cell populations during muscle homeostasis, regeneration, and aging are unclear. Here, we discuss how the stem cell neighborhood influences satellite cell behavior and bring together recent discoveries pertaining to a wide variety of adult stem cells, including muscle stem cells and their niche.
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Affiliation(s)
- Alice Pannérec
- Myology Group, UMR S 787 INSERM, Université Pierre et Marie Curie Paris VI, Paris, 75634, France
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