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Hidema S, Tonomura Y, Date S, Nishimori K. Effects of protein transduction with intact myogenic transcription factors tagged with HIV-1 Tat-PTD (T-PTD) on myogenic differentiation of mouse primary cells. J Biosci Bioeng 2012; 113:5-11. [DOI: 10.1016/j.jbiosc.2011.08.025] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2011] [Revised: 08/19/2011] [Accepted: 08/25/2011] [Indexed: 12/11/2022]
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102
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Takagaki Y, Yamagishi H, Matsuoka R. Factors Involved in Signal Transduction During Vertebrate Myogenesis. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2012; 296:187-272. [DOI: 10.1016/b978-0-12-394307-1.00004-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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103
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Mancinelli R, Pietrangelo T, Burnstock G, Fanò G, Fulle S. Transcriptional profile of GTP-mediated differentiation of C2C12 skeletal muscle cells. Purinergic Signal 2011; 8:207-21. [PMID: 22127439 DOI: 10.1007/s11302-011-9266-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2010] [Accepted: 10/03/2011] [Indexed: 02/01/2023] Open
Abstract
Several purine receptors have been localised on skeletal muscle membranes. Previous data support the hypothesis that extracellular guanosine 5'-triphosphate (GTP) is an important regulatory factor in the development and function of muscle tissue. We have previously described specific extracellular binding sites for GTP on the plasma membrane of mouse skeletal muscle (C2C12) cells. Extracellular GTP induces an increase in intracellular Ca(2+) concentrations that results in membrane hyperpolarisation through Ca(2+)-activated K(+) channels, as has been demonstrated by patch-clamp experiments. This GTP-evoked increase in intracellular Ca(2+) is due to release of Ca(2+) from intracellular inositol-1,4,5-trisphosphate-sensitive stores. This enhances the expression of the myosin heavy chain in these C2C12 myoblasts and commits them to fuse into multinucleated myotubes, probably via a phosphoinositide-3-kinase-dependent signal-transduction mechanism. To define the signalling of extracellular GTP as an enhancer or modulator of myogenesis, we investigated whether the gene-expression profile of differentiated C2C12 cells (4 and 24 h in culture) is affected by extracellular GTP. To investigate the nuclear activity and target genes modulated by GTP, transcriptional profile analysis and real-time PCR were used. We demonstrate that in the early stages of differentiation, GTP up-regulates genes involved in different pathways associated with myogenic processes, including cytoskeleton structure, the respiratory chain, myogenesis, chromatin reorganisation, cell adhesion, and the Jak/Stat pathway, and down-regulates the mitogen-activated protein kinase pathway. GTP also increases the expression of three genes involved in myogenesis, Pp3ca, Gsk3b, and Pax7. Our data suggests that in the myogenic C2C12 cell line, extracellular GTP acts as a differentiative factor in the induction and sustaining of myogenesis.
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Affiliation(s)
- Rosa Mancinelli
- Department of Neuroscience and Imaging, University G. d'Annunzio Chieti-Pescara, Chieti, Italy.
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104
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Gaetz J, Clift KL, Fernandes CJ, Mao FF, Lee JH, Zhang L, Baker SW, Looney TJ, Foshay KM, Yu WH, Xiang AP, Lahn BT. Evidence for a critical role of gene occlusion in cell fate restriction. Cell Res 2011; 22:848-58. [PMID: 22124232 DOI: 10.1038/cr.2011.190] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
The progressive restriction of cell fate during lineage differentiation is a poorly understood phenomenon despite its ubiquity in multicellular organisms. We recently used a cell fusion assay to define a mode of epigenetic silencing that we termed "occlusion", wherein affected genes are silenced by cis-acting chromatin mechanisms irrespective of whether trans-acting transcriptional activators are present. We hypothesized that occlusion of lineage-inappropriate genes could contribute to cell fate restriction. Here, we test this hypothesis by introducing bacterial artificial chromosomes (BACs), which are devoid of chromatin modifications necessary for occlusion, into mouse fibroblasts. We found that BAC transgenes corresponding to occluded endogenous genes are expressed in most cases, whereas BAC transgenes corresponding to silent but non-occluded endogenous genes are not expressed. This indicates that the cellular milieu in trans supports the expression of most occluded genes in fibroblasts, and that the silent state of these genes is solely the consequence of occlusion in cis. For the BAC corresponding to the occluded myogenic master regulator Myf5, expression of the Myf5 transgene on the BAC triggered fibroblasts to acquire a muscle-like phenotype. These results provide compelling evidence for a critical role of gene occlusion in cell fate restriction.
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Affiliation(s)
- Jedidiah Gaetz
- Department of Human Genetics, University of Chicago, Howard Hughes Medical Institute, Chicago, IL 60637, USA
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105
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Protein tyrosine phosphatase-like A regulates myoblast proliferation and differentiation through MyoG and the cell cycling signaling pathway. Mol Cell Biol 2011; 32:297-308. [PMID: 22106411 DOI: 10.1128/mcb.05484-11] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Protein tyrosine phosphatase-like A (PTPLa) has been implicated in skeletal myogenesis and cardiogenesis. Mutations in PTPLa correlated with arrhythmogenic right ventricular dysplasia in humans and congenital centronuclear myopathy with severe hypotonia in dogs. The molecular mechanisms of PTPLa in myogenesis are unknown. In this report, we demonstrate that PTPLa is required for myoblast growth and differentiation. The cells lacking PTPLa remained immature and failed to differentiate into mature myotubes. The repressed MyoG expression was responsible for the impaired myoblast differentiation. Meanwhile, impeded cell growth, with an obvious S-phase arrest and compromised G(2)/M transition, was observed in PTPLa-deficient myoblasts. Further study demonstrated that the upregulation of cyclin D1 and cyclin E2 complexes, along with a compromised G(2)/M transition due to the decreased CDK1 (cyclin-dependent kinase 1) activity and upregulated p21, contributed to the mutant cell S-phase arrest and eventually led to the retarded cell growth. Finally, the transcriptional regulation of the PTPLa gene was explored. We identified PTPLa as a new target gene of the serum response factor (SRF). Skeletal- and cardiac-muscle-specific SRF knockouts resulted in significant decreases in PTPLa expression, suggesting a conserved transcriptional regulation of the PTPLa gene in mice.
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106
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Xue M, Zan LS, Gao L, Wang HB. A novel polymorphism of the myogenin gene is associated with body measurement traits in native Chinese breeds. GENETICS AND MOLECULAR RESEARCH 2011; 10:2721-8. [PMID: 22095598 DOI: 10.4238/2011.november.4.6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Using PCR-SSCP and DNA sequencing technology, we examined the association of single nucleotide polymorphisms (SNPs) in the bovine MyoG gene with body measurement traits in 779 individuals of six native Chinese cattle breeds, namely Luxi, Luxi × Simmental crossbred, Nanyang, Xia'nan, Jiaxian red, and Qinchuan. A novel SNP, T314C, was detected. Allelic frequencies of MyoG-T/C in the six breeds were 0.8308/0.1692, 0.8774/0.1226, 0.8021/0.1979, 0.8209/0.1791, 0.8630/0.1370, 0.8044/0.1956, respectively. Least squares analysis revealed a significant (P < 0.05) association of the MyoG SNP with rump length in four breeds (Luxi, Xia'nan, Jiaxian red, and Qinchuan), with hucklebone width in three breeds (Luxi × Simmental crossbred, Nanyang and Xia'nan), with waist height in two breeds (Luxi × Simmental crossbred and Nanyang) and with body length in the Luxi breed. We conclude that the MyoG SNP has potential as a genetic marker for economically relevant body measurement traits in native Chinese cattle breeds.
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Affiliation(s)
- M Xue
- College of Animal Science and Technology, Northwest Agriculture and Forestry University, Yangling, Shaanxi, PR China
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107
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Li X, Wang X, Zhang P, Zhu L, Zhao T, Liu S, Wu Y, Chen X, Fan M. Extracellular signal-regulated kinase 1/2 mitogen-activated protein kinase pathway is involved in inhibition of myogenic differentiation of myoblasts by hypoxia. Exp Physiol 2011; 97:257-64. [PMID: 22002869 DOI: 10.1113/expphysiol.2011.061382] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Oxygen conditions influence a variety of biological processes of cells, including alterations in cellular growth, survival and differentiation. However, there have been few studies on the effects of hypoxia on proliferation and differentiation of myoblasts. In this study, we observed the effects of hypoxia (3% O(2)) on myogenic differentiation of C2C12 myoblasts and sought a possible mechanism involved in the regulation of myogenic differentiation of myoblasts by hypoxia. The expression of myosin heavy chain was detected by immunocytochemistry staining and Western blot analysis. The expression of muscle regulatory transcription factors was examined by RT-PCR analysis and Western blot analysis. The activity of extracellular signal-regulated kinases (ERK1/2) was investigated by forced expression of mitogen-activated protein kinase kinase 1 (MEK1(E)) and using Western blot analysis. We found that hypoxia inhibited myogenic differentiation of myoblasts. The expression of muscle regulatory transcription factors was downregulated by hypoxia in C2C12 myoblasts. During the inhibition of myogenic differentiation by hypoxia, ERK1/2 activation was suppressed, and increasing ERK1/2 activity by forced expression of MEK1(E) could partly reverse the inhibition of myogenic differentiation by hypoxia. These results suggest that the ERK1/2-mitogen-activated protein kinase pathway might be a possible mechanism involved in the inhibition of myogenic differentiation by hypoxia.
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Affiliation(s)
- Xiang Li
- Department of Brain Protection, Institute of Basic Medical Sciences, 27 Taiping Road, Beijing 100850, PR China
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108
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Green YS, Vetter ML. EBF proteins participate in transcriptional regulation of Xenopus muscle development. Dev Biol 2011; 358:240-50. [PMID: 21839736 DOI: 10.1016/j.ydbio.2011.07.034] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2010] [Revised: 07/24/2011] [Accepted: 07/27/2011] [Indexed: 01/08/2023]
Abstract
EBF proteins have diverse functions in the development of multiple lineages, including neurons, B cells and adipocytes. During Drosophila muscle development EBF proteins are expressed in muscle progenitors and are required for muscle cell differentiation, but there is no known function of EBF proteins in vertebrate muscle development. In this study, we examine the expression of ebf genes in Xenopus muscle tissue and show that EBF activity is necessary for aspects of Xenopus skeletal muscle development, including somite organization, migration of hypaxial muscle anlagen toward the ventral abdomen, and development of jaw muscle. From a microarray screen, we have identified multiple candidate targets of EBF activity with known roles in muscle development. The candidate targets we have verified are MYOD, MYF5, M-Cadherin and SEB-4. In vivo overexpression of the ebf2 and ebf3 genes leads to ectopic expression of these candidate targets, and knockdown of EBF activity causes downregulation of the endogenous expression of the candidate targets. Furthermore, we found that MYOD and MYF5 are likely to be direct targets. Finally we show that MYOD can upregulate the expression of ebf genes, indicating the presence of a positive feedback loop between EBF and MYOD that we find to be important for maintenance of MYOD expression in Xenopus. These results suggest that EBF activity is important for both stabilizing commitment and driving aspects of differentiation in Xenopus muscle cells.
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Affiliation(s)
- Yangsook Song Green
- Department of Neurobiology and Anatomy, University of Utah School of Medicine, Salt Lake City, UT 84132, USA.
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109
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Gyurján I, Sonderegger B, Naef F, Duboule D. Analysis of the dynamics of limb transcriptomes during mouse development. BMC DEVELOPMENTAL BIOLOGY 2011; 11:47. [PMID: 21801425 PMCID: PMC3160909 DOI: 10.1186/1471-213x-11-47] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/04/2011] [Accepted: 07/29/2011] [Indexed: 11/10/2022]
Abstract
BACKGROUND The development of vertebrate limbs has been a traditional system to study fundamental processes at work during ontogenesis, such as the establishment of spatial cellular coordinates, the effect of diffusible morphogenetic molecules or the translation between gene activity and morphogenesis. In addition, limbs are amongst the first targets of malformations in human and they display a huge realm of evolutionary variations within tetrapods, which make them a paradigm to study the regulatory genome. RESULTS As a reference resource for future biochemical and genetic analyses, we used genome-wide tiling arrays to establish the transcriptomes of mouse limb buds at three different stages, during which major developmental events take place. We compare the three time-points and discuss some aspects of these datasets, for instance related to transcriptome dynamics or to the potential association between active genes and the distribution of intergenic transcriptional activity. CONCLUSIONS These datasets provide a valuable resource, either for research projects involving gene expression and regulation in developing mouse limbs, or as examples of tissue-specific, genome-wide transcriptional activities.
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Affiliation(s)
- Istvan Gyurján
- School of Life Sciences, Ecole Polytechnique Fédérale, Station 19, Lausanne, 1215 Switzerland
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110
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Sim H, Argentaro A, Czech DP, Bagheri-Fam S, Sinclair AH, Koopman P, Boizet-Bonhoure B, Poulat F, Harley VR. Inhibition of SRY-calmodulin complex formation induces ectopic expression of ovarian cell markers in developing XY gonads. Endocrinology 2011; 152:2883-93. [PMID: 21558314 DOI: 10.1210/en.2010-1475] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The transcription factor sex-determining region of the Y chromosome (SRY) plays a key role in human sex determination, because mutations in SRY cause disorders of sex development in XY individuals. During gonadal development, Sry in pre-Sertoli cells activates Sox9 gene transcription, committing the fate of the bipotential gonad to become a testis rather than an ovary. The high-mobility group domain of human SRY contains two independent nuclear localization signals, one bound by calmodulin (CaM) and the other by importin-β. Although XY females carry SRY mutations in these nuclear localization signals that affect SRY nuclear import in transfected cells, it is not known whether these transport mechanisms are essential for gonadal development and sex determination. Here, we show that mouse Sry protein binds CaM and that a CaM antagonist reduces CaM binding, nuclear accumulation, and transcriptional activity of Sry in transfected cells. CaM antagonist treatment of cultured, sexually indifferent XY mouse fetal gonads led to reduced expression of the Sry target gene Sox9, defects in testicular cord formation, and ectopic expression of the ovarian markers Rspondin1 and forkhead box L2. These results indicate the importance of CaM for SRY nuclear import, transcriptional activity, testis differentiation, and sex determination.
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Affiliation(s)
- Helena Sim
- Molecular Genetics and Development Division, Prince Henry's Institute of Medical Research, Level 4 Block E, Monash Medical Centre, 246 Clayton Road, Clayton, Melbourne, Victoria 3168, Australia
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111
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Low-molecular-weight fucoidan regulates myogenic differentiation through the mitogen-activated protein kinase pathway in C2C12 cells. Br J Nutr 2011; 106:1836-44. [PMID: 21682942 DOI: 10.1017/s0007114511002534] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Low-molecular-weight fucoidan (LMWF) has been broadly studied in recent years due to its numerous biological properties. Nevertheless, there have been no reports about the effects of LMWF on myogenic differentiation (MyoD). The objective of the present study was to demonstrate the impact of LMWF on myogenesis in C2C12 cells. The ultimate aim was to establish whether LMWF regulates myogenesis similar to heparin as a partial regulator of myogenesis. LMWF was prepared at a minimal size by ultra-filtration compared with crude fucoidan. We treated C2C12 cells with LMWF and/or heparin during MyoD. The data from the present study are the first to suggest that LMWF suppresses the expression of the myogenic regulatory factors and the myocyte enhancer factors as well as the morphological changes that occur during differentiation. Additionally, the expression of the mitogen-activated protein kinase (MAPK) family was significantly inhibited by LMWF when compared with controls. The LMWF-treated group showed significantly decreased expression of reactive oxygen species (ROS) enzymes compared with control cells. Heparin was used as a positive control because it has been reported to activate MyoD. Taken together, these results suggest that LMWF might regulate MyoD through the MAPK pathway and by regulating ROS activity in C2C12 cells.
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112
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Simeoni I, Gilchrist MJ, Garrett N, Armisen J, Gurdon JB. Widespread transcription in an amphibian oocyte relates to its reprogramming activity on transplanted somatic nuclei. Stem Cells Dev 2011; 21:181-90. [PMID: 21504359 DOI: 10.1089/scd.2011.0162] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Amphibian oocytes have the special ability to directly induce the transcription of pluripotency and other genes in transplanted somatic nuclei. To this extent, oocytes induce a stem cell-like pattern of transcription in somatic cell nuclei. We ask whether the induced transcription in transplanted nuclei reflects the normal transcriptional activity of oocyte genes. We describe here the transcript content of a wide range of genes in Xenopus tropicalis oocytes. Using accurate quantitation, we find that each mature oocyte has accumulated several hundred transcripts of cell-type specific genes. This value is several orders of magnitude greater than the "leakage" level found in most somatic cells and about the same level found in somatic cells where these genes are fully expressed. Illumina sequencing confirms the high transcript content of a mature Xenopus oocyte. Most of the transcripts from these highly expressed genes in oocytes are correctly and efficiently spliced. Our results contribute a more quantitative view of certain amphibian oocyte transcripts than previously available. Our results also show that transplanted somatic nuclei conform, with respect to the genes analyzed, to the transcriptional characteristics of the recipient oocytes.
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Affiliation(s)
- Ilenia Simeoni
- Wellcome Trust Cancer Research UK Gurdon Institute, University of Cambridge, Cambridge, United Kingdom
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113
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Balan OV, Ozernuk ND. Expression of the gene MyoD and m-cadherin in the myogenic precursor cell culture isolated from muscles of rats at different stages of ontogenesis. BIOL BULL+ 2011. [DOI: 10.1134/s1062359011020026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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114
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Secretome Analysis of Skeletal Myogenesis Using SILAC and Shotgun Proteomics. INTERNATIONAL JOURNAL OF PROTEOMICS 2011; 2011:329467. [PMID: 22084683 PMCID: PMC3200090 DOI: 10.1155/2011/329467] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/15/2010] [Accepted: 01/26/2011] [Indexed: 12/18/2022]
Abstract
Myogenesis, the formation of skeletal muscle, is a multistep event that commences with myoblast proliferation, followed by cell-cycle arrest, and finally the formation of multinucleated myotubes via fusion of mononucleated myoblasts. Each step is orchestrated by well-documented intracellular factors, such as cytoplasmic signalling molecules and nuclear transcription factors. Regardless, the key step in getting a more comprehensive understanding of the regulation of myogenesis is to explore the extracellular factors that are capable of eliciting the downstream intracellular factors. This could further provide valuable insight into the acute cellular response to extrinsic cues in maintaining normal muscle development. In this paper, we survey the intracellular factors that respond to extracellular cues that are responsible for the cascades of events during myogenesis: myoblast proliferation, cell-cycle arrest of myoblasts, and differentiation of myoblasts into myotubes. This focus on extracellular perspective of muscle development illustrates our mass spectrometry-based proteomic approaches to identify differentially expressed secreted factors during skeletal myogenesis.
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115
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Chan CYX, Masui O, Krakovska O, Belozerov VE, Voisin S, Ghanny S, Chen J, Moyez D, Zhu P, Evans KR, McDermott JC, Siu KWM. Identification of differentially regulated secretome components during skeletal myogenesis. Mol Cell Proteomics 2011; 10:M110.004804. [PMID: 21343469 DOI: 10.1074/mcp.m110.004804] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Myogenesis is a well-characterized program of cellular differentiation that is exquisitely sensitive to the extracellular milieu. Systematic characterization of the myogenic secretome (i.e. the ensemble of secreted proteins) is, therefore, warranted for the identification of novel secretome components that regulate both the pluripotency of these progenitor mesenchymal cells, and also their commitment and passage through the differentiation program. Previously, we have successfully identified 26 secreted proteins in the mouse skeletal muscle cell line C2C12 (1). In an effort to attain a more comprehensive picture of the regulation of myogenesis by its extracellular milieu, quantitative profiling employing stable isotope labeling by amino acids in cell culture was implemented in conjunction with two parallel high throughput online reverse phase liquid chromatography-tandem mass spectrometry systems. In summary, 34 secreted proteins were quantified, 30 of which were shown to be differentially expressed during muscle development. Intriguingly, our analysis has revealed several novel up- and down-regulated secretome components that may have critical biological relevance for both the maintenance of pluripotency and the passage of cells through the differentiation program. In particular, the altered regulation of secretome components, including follistatin-like protein-1, osteoglycin, spondin-2, and cytokine-induced apoptosis inhibitor-1, along with constitutively expressed factors, such as fibulin-2, illustrate dynamic changes in the secretome that take place when differentiation to a specific lineage occurs.
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Affiliation(s)
- C Y X'avia Chan
- Department of Biology, York University, 4700 Keele Street, Toronto, Ontario, Canada
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116
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Dumke BR, Lees SJ. Age-related impairment of T cell-induced skeletal muscle precursor cell function. Am J Physiol Cell Physiol 2011; 300:C1226-33. [PMID: 21325640 DOI: 10.1152/ajpcell.00354.2010] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Sarcopenia is the age-associated loss of skeletal muscle mass and strength. Recent evidence suggests that an age-associated loss of muscle precursor cell (MPC) functionality contributes to sarcopenia. The objectives of the present study were to examine the influence of activated T cells on MPCs and determine whether an age-related defect in this signaling occurs. MPCs were collected from the gastrocnemius and plantaris of 3-mo-old (young) and 32-mo-old (old) animals. Splenic T cells were harvested using anti-CD3 Dynabead isolation. T cells were activated for 48 h with costimulation of 100 IU/ml interleukin-2 (IL-2) and 5 μg/ml of anti-CD28. Costimulation increased 5-bromo-2'-deoxyuridine incorporation of T cells from 13.4 ± 4.6% in control to 64.8 ± 6.0% in costimulated cells. Additionally, T cell cytokines increased proliferation on MPCs isolated from young muscle by 24.0 ± 5.7%, whereas there was no effect on MPCs isolated from aged muscle. T cell cytokines were also found to be a chemoattractant. T cells were able to promote migration of MPCs isolated from young muscle; however, MPCs isolated from aged muscle did not respond to the T cell-released chemokines. Conversely, whereas T cell-released cytokines did not affect myogenesis of MPCs isolated from young animals, there was a decrease in MPCs isolated from old animals. These data suggest that T cells may play a critical role in mediating MPC function. Furthermore, aging may alter T cell-induced MPC function. These findings have implications for developing strategies aimed at increasing MPC migration and proliferation leading to an improved regenerative capacity of aged skeletal muscle.
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Affiliation(s)
- Breanna R Dumke
- Medical Sciences Division, Northern Ontario School of Medicine, 955 Oliver Rd., Thunder Bay, Ontario, Canada
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117
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von Maltzahn J, Wulf V, Matern G, Willecke K. Connexin39 deficient mice display accelerated myogenesis and regeneration of skeletal muscle. Exp Cell Res 2011; 317:1169-78. [PMID: 21272575 DOI: 10.1016/j.yexcr.2011.01.017] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2010] [Revised: 01/14/2011] [Accepted: 01/15/2011] [Indexed: 12/19/2022]
Abstract
During muscle development and regeneration of skeletal muscle in mice connexin43 (Cx43) and connexin39 (Cx39) are specifically expressed: Cx43 in satellite cells and myoblasts, whereas Cx39 is exclusively expressed in myogenin-positive cells. We generated Cx39 deficient mice by replacing the coding region of the Gjd4 gene by DNA coding for the enhanced green fluorescent protein eGFP. Adult Cx39 deficient mice exhibit no obvious phenotypic alterations of skeletal muscle compared to wild type mice in the resting state. However, myogenesis in Cx39 deficient embryos is accelerated as indicated by increased myogenin expression on ED13.5 and ED16.5 and increased expression of Cx43 in developing skeletal muscle. In addition, the regeneration process of skeletal muscle in Cx39 deficient mice is accelerated as shown by a 2day earlier onset of MyoD and myogenin expression, relative to wild type littermates. Interestingly, Cx43 expression was also upregulated in Cx39 deficient mice during regeneration of skeletal muscle. We hypothesize that Cx43 may compensate for the loss of Cx39 during myogenesis and regeneration.
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118
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Ciemerych MA, Archacka K, Grabowska I, Przewoźniak M. Cell cycle regulation during proliferation and differentiation of mammalian muscle precursor cells. Results Probl Cell Differ 2011; 53:473-527. [PMID: 21630157 DOI: 10.1007/978-3-642-19065-0_20] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Proliferation and differentiation of muscle precursor cells are intensively studied not only in the developing mouse embryo but also using models of skeletal muscle regeneration or analyzing in vitro cultured cells. These analyses allowed to show the universality of the cell cycle regulation and also uncovered tissue-specific interplay between major cell cycle regulators and factors crucial for the myogenic differentiation. Examination of the events accompanying proliferation and differentiation leading to the formation of functional skeletal muscle fibers allows understanding the molecular basis not only of myogenesis but also of skeletal muscle regeneration. This chapter presents the basis of the cell cycle regulation in proliferating and differentiating muscle precursor cells during development and after muscle injury. It focuses at major cell cycle regulators, myogenic factors, and extracellular environment impacting on the skeletal muscle.
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Affiliation(s)
- Maria A Ciemerych
- Department of Cytology, Institute of Zoology, University of Warsaw, Miecznikowa 1, 02-096 Warsaw, Poland.
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119
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120
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Stein R. Insulin Gene Transcription: Factors Involved in Cell Type–Specific and Glucose‐Regulated Expression in Islet β Cells are Also Essential During Pancreatic Development. Compr Physiol 2011. [DOI: 10.1002/cphy.cp070202] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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121
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Saab R, Spunt SL, Skapek SX. Myogenesis and rhabdomyosarcoma the Jekyll and Hyde of skeletal muscle. Curr Top Dev Biol 2011; 94:197-234. [PMID: 21295688 DOI: 10.1016/b978-0-12-380916-2.00007-3] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Rhabdomyosarcoma, a neoplasm composed of skeletal myoblast-like cells, represents the most common soft tissue sarcoma in children. The application of intensive chemotherapeutics and refined surgical and radiation therapy approaches have improved survival for children with localized disease over the past 3 decades; however, these approaches have not improved the dismal outcome for children with metastatic and recurrent rhabdomyosarcoma. Elegant studies have defined the molecular mechanisms driving skeletal muscle lineage commitment and differentiation, and the machinery that couples differentiation with irreversible cell proliferation arrest. Further, detailed molecular analyses indicate that rhabdomyosarcoma cells have lost the capacity to fully differentiate when challenged to do so in experimental models. We review the intersection of normal skeletal muscle developmental biology and the molecular genetic defects in rhabdomyosarcoma with the underlying premise that understanding how the differentiation process has gone awry will lead to new treatment strategies aimed at promoting myogenic differentiation and concomitant cell cycle arrest.
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Affiliation(s)
- Raya Saab
- Children's Cancer Center of Lebanon, Department of Pediatrics, American University of Beirut, Beirut, Lebanon
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122
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Punch VG, Jones AE, Rudnicki MA. Transcriptional networks that regulate muscle stem cell function. WILEY INTERDISCIPLINARY REVIEWS-SYSTEMS BIOLOGY AND MEDICINE 2010; 1:128-140. [PMID: 20835986 DOI: 10.1002/wsbm.11] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Muscle stem cells comprise different populations of stem and progenitor cells found in embryonic and adult tissues. A number of signaling and transcriptional networks are responsible for specification and survival of these cell populations and regulation of their behavior during growth and regeneration. Muscle progenitor cells are mostly derived from the somites of developing embryos, while satellite cells are the progenitor cells responsible for the majority of postnatal growth and adult muscle regeneration. In resting muscle, these stem cells are quiescent, but reenter the cell cycle during their activation, whereby they undergo decisions to self-renew, proliferate, or differentiate and fuse into multinucleated myofibers to repair damaged muscle. Regulation of muscle stem cell activity is under the precise control of a number of extrinsic signaling pathways and active transcriptional networks that dictate their behavior, fate, and regenerative potential. Here, we review the networks responsible for these different aspects of muscle stem cell biology and discuss prevalent parallels between mechanisms regulating the activity of embryonic muscle progenitor cells and adult satellite cells.
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Affiliation(s)
- Vincent G Punch
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Canada
- The Sprott Centre for Stem Cell Research, Ottawa Health Research Institute, Ottawa, Canada
| | - Andrew E Jones
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Canada
- The Sprott Centre for Stem Cell Research, Ottawa Health Research Institute, Ottawa, Canada
| | - Michael A Rudnicki
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Canada
- The Sprott Centre for Stem Cell Research, Ottawa Health Research Institute, Ottawa, Canada
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123
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Micheli L, Leonardi L, Conti F, Maresca G, Colazingari S, Mattei E, Lira SA, Farioli-Vecchioli S, Caruso M, Tirone F. PC4/Tis7/IFRD1 stimulates skeletal muscle regeneration and is involved in myoblast differentiation as a regulator of MyoD and NF-kappaB. J Biol Chem 2010; 286:5691-707. [PMID: 21127072 PMCID: PMC3037682 DOI: 10.1074/jbc.m110.162842] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
In skeletal muscle cells, the PC4 (Tis7/Ifrd1) protein is known to function as a coactivator of MyoD by promoting the transcriptional activity of myocyte enhancer factor 2C (MEF2C). In this study, we show that up-regulation of PC4 in vivo in adult muscle significantly potentiates injury-induced regeneration by enhancing myogenesis. Conversely, we observe that PC4 silencing in myoblasts causes delayed exit from the cell cycle, accompanied by delayed differentiation, and we show that such an effect is MyoD-dependent. We provide evidence revealing a novel mechanism underlying the promyogenic actions of PC4, by which PC4 functions as a negative regulator of NF-κB, known to inhibit MyoD expression post-transcriptionally. In fact, up-regulation of PC4 in primary myoblasts induces the deacetylation, and hence the inactivation and nuclear export of NF-κB p65, in concomitance with induction of MyoD expression. On the contrary, PC4 silencing in myoblasts induces the acetylation and nuclear import of p65, in parallel with a decrease of MyoD levels. We also observe that PC4 potentiates the inhibition of NF-κB transcriptional activity mediated by histone deacetylases and that PC4 is able to form trimolecular complexes with p65 and HDAC3. This suggests that PC4 stimulates deacetylation of p65 by favoring the recruitment of HDAC3 to p65. As a whole, these results indicate that PC4 plays a role in muscle differentiation by controlling the MyoD pathway through multiple mechanisms, and as such, it positively regulates regenerative myogenesis.
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Affiliation(s)
- Laura Micheli
- Istituto di Neurobiologia e Medicina Molecolare, Consiglio Nazionale delle Ricerche, Fondazione S Lucia, Via del Fosso di Fiorano 64, 00143 Rome, Italy
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124
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Waddell JN, Zhang P, Wen Y, Gupta SK, Yevtodiyenko A, Schmidt JV, Bidwell CA, Kumar A, Kuang S. Dlk1 is necessary for proper skeletal muscle development and regeneration. PLoS One 2010; 5:e15055. [PMID: 21124733 PMCID: PMC2993959 DOI: 10.1371/journal.pone.0015055] [Citation(s) in RCA: 97] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2010] [Accepted: 10/15/2010] [Indexed: 11/18/2022] Open
Abstract
Delta-like 1homolog (Dlk1) is an imprinted gene encoding a transmembrane protein whose increased expression has been associated with muscle hypertrophy in animal models. However, the mechanisms by which Dlk1 regulates skeletal muscle plasticity remain unknown. Here we combine conditional gene knockout and over-expression analyses to investigate the role of Dlk1 in mouse muscle development, regeneration and myogenic stem cells (satellite cells). Genetic ablation of Dlk1 in the myogenic lineage resulted in reduced body weight and skeletal muscle mass due to reductions in myofiber numbers and myosin heavy chain IIB gene expression. In addition, muscle-specific Dlk1 ablation led to postnatal growth retardation and impaired muscle regeneration, associated with augmented myogenic inhibitory signaling mediated by NF-κB and inflammatory cytokines. To examine the role of Dlk1 in satellite cells, we analyzed the proliferation, self-renewal and differentiation of satellite cells cultured on their native host myofibers. We showed that ablation of Dlk1 inhibits the expression of the myogenic regulatory transcription factor MyoD, and facilitated the self-renewal of activated satellite cells. Conversely, Dlk1 over-expression inhibited the proliferation and enhanced differentiation of cultured myoblasts. As Dlk1 is expressed at low levels in satellite cells but its expression rapidly increases upon myogenic differentiation in vitro and in regenerating muscles in vivo, our results suggest a model in which Dlk1 expressed by nascent or regenerating myofibers non-cell autonomously promotes the differentiation of their neighbor satellite cells and therefore leads to muscle hypertrophy.
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MESH Headings
- Animals
- Blotting, Western
- Calcium-Binding Proteins
- Cell Differentiation
- Cell Line
- Cell Proliferation
- Cells, Cultured
- Immunohistochemistry
- Intercellular Signaling Peptides and Proteins/genetics
- Intercellular Signaling Peptides and Proteins/metabolism
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Muscle Fibers, Skeletal/cytology
- Muscle Fibers, Skeletal/metabolism
- Muscle, Skeletal/metabolism
- Muscle, Skeletal/physiology
- MyoD Protein/genetics
- MyoD Protein/metabolism
- Myoblasts/cytology
- Myoblasts/metabolism
- Regeneration
- Reverse Transcriptase Polymerase Chain Reaction
- Satellite Cells, Skeletal Muscle/cytology
- Satellite Cells, Skeletal Muscle/metabolism
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Affiliation(s)
- Jolena N. Waddell
- Department of Animal Sciences, Purdue University, West Lafayette, Indiana, United States of America
| | - Peijing Zhang
- Department of Animal Sciences, Purdue University, West Lafayette, Indiana, United States of America
| | - Yefei Wen
- Department of Animal Sciences, Purdue University, West Lafayette, Indiana, United States of America
| | - Sanjay K. Gupta
- Department of Anatomical Sciences and Neurobiology, University of Louisville School of Medicine, Louisville, Kentucky, United States of America
| | - Aleksey Yevtodiyenko
- Division of Oncology, School of Medicine, Stanford University, Stanford, California, United States of America
| | - Jennifer V. Schmidt
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, Illinois, United States of America
| | - Christopher A. Bidwell
- Department of Animal Sciences, Purdue University, West Lafayette, Indiana, United States of America
| | - Ashok Kumar
- Department of Anatomical Sciences and Neurobiology, University of Louisville School of Medicine, Louisville, Kentucky, United States of America
| | - Shihuan Kuang
- Department of Animal Sciences, Purdue University, West Lafayette, Indiana, United States of America
- Center for Cancer Research, Purdue University, West Lafayette, Indiana, United States of America
- * E-mail:
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125
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Gianakopoulos PJ, Mehta V, Voronova A, Cao Y, Yao Z, Coutu J, Wang X, Waddington MS, Tapscott SJ, Skerjanc IS. MyoD directly up-regulates premyogenic mesoderm factors during induction of skeletal myogenesis in stem cells. J Biol Chem 2010; 286:2517-25. [PMID: 21078671 DOI: 10.1074/jbc.m110.163709] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Gain- and loss-of-function experiments have illustrated that the family of myogenic regulatory factors is necessary and sufficient for the formation of skeletal muscle. Furthermore, MyoD required cellular aggregation to induce myogenesis in P19 embryonal carcinoma stem cells. To determine the mechanism by which stem cells can be directed into skeletal muscle, a time course of P19 cell differentiation was examined in the presence and absence of exogenous MyoD. By quantitative PCR, the first MyoD up-regulated transcripts were the premyogenic mesoderm factors Meox1, Pax7, Six1, and Eya2 on day 4 of differentiation. Subsequently, the myoblast markers myogenin, MEF2C, and Myf5 were up-regulated, leading to skeletal myogenesis. These results were corroborated by Western blot analysis, showing up-regulation of Pax3, Six1, and MEF2C proteins, prior to myogenin protein expression. To determine at what stage a dominant-negative MyoD/EnR mutant could inhibit myogenesis, stable cell lines were created and examined. Interestingly, the premyogenic mesoderm factors, Meox1, Pax3/7, Six1, Eya2, and Foxc1, were down-regulated, and as expected, skeletal myogenesis was abolished. Finally, to identify direct targets of MyoD in this system, chromatin immunoprecipitation experiments were performed. MyoD was observed associated with regulatory regions of Meox1, Pax3/7, Six1, Eya2, and myogenin genes. Taken together, MyoD directs stem cells into the skeletal muscle lineage by binding and activating the expression of premyogenic mesoderm genes, prior to activating myoblast genes.
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Affiliation(s)
- Peter J Gianakopoulos
- Department of Biochemistry, Microbiology, and Immunology, University of Ottawa, Ottawa, Ontario K1H 8M5, Canada
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126
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Jahan E, Matsumoto A, Udagawa J, Rafiq AM, Hashimoto R, Rahman OIF, Habib H, Sekine J, Otani H. Effects of restriction of fetal jaw movement on prenatal development of the temporalis muscle. Arch Oral Biol 2010; 55:919-27. [PMID: 20728868 DOI: 10.1016/j.archoralbio.2010.07.010] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2010] [Revised: 06/14/2010] [Accepted: 07/27/2010] [Indexed: 12/29/2022]
Abstract
Jaw movement affects masticatory muscles during the postnatal period. Prenatal jaw movement has also been implicated in the development of the temporomandibular joint; however, its effect on prenatal development of the masticatory muscles has not been extensively analysed. In the present study, we examined the effects of the restriction of fetal jaw movement on the temporalis muscle, a major masticatory muscle, in mice by suturing the maxilla and mandible (sutured group) using an exo utero development system. We compared the morphology of the temporalis muscle between sutured, sham-operated and normal in utero groups. At embryonic day (E) 18.5, the volume of muscle fibres, but not that of connective tissue, in the temporalis muscle was decreased in the sutured group. The E18.5 temporalis muscle in the sutured group appeared morphologically similar to that of the E17.5 in utero group, except for frequent muscle fibre irregularities. By transmission electron microscopy, in the sutured group, the myofibrils were immature and scattered, the nuclei appeared comparatively immature, the mitochondria were expanded in volume with fewer cristae, and cytoplasmic inclusion bodies were frequently observed. Expression of Myf-6, a late myogenic transcription factor, by real-time RT-PCR was not significantly different between the sutured and sham-operated groups. These findings demonstrated approximately 1-day delay in the morphological development of the temporalis muscle in the sutured group, and some abnormalities were observed, although Myf-6 level was not affected in the sutured group. The present study revealed that the prenatal jaw movement influences the development of the temporalis muscle.
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Affiliation(s)
- Esrat Jahan
- Department of Developmental Biology, Shimane University, Enya-cho, Izumoshi, Japan
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127
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Bower NI, Johnston IA. Discovery and characterization of nutritionally regulated genes associated with muscle growth in Atlantic salmon. Physiol Genomics 2010; 42A:114-30. [PMID: 20663983 DOI: 10.1152/physiolgenomics.00065.2010] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
A genomics approach was used to identify nutritionally regulated genes involved in growth of fast skeletal muscle in Atlantic salmon (Salmo salar L.). Forward and reverse subtractive cDNA libraries were prepared comparing fish with zero growth rates to fish growing rapidly. We produced 7,420 ESTs and assembled them into nonredundant clusters prior to annotation. Contigs representing 40 potentially unrecognized nutritionally responsive candidate genes were identified. Twenty-three of the subtractive library candidates were also differentially regulated by nutritional state in an independent fasting-refeeding experiment and their expression placed in the context of 26 genes with established roles in muscle growth regulation. The expression of these genes was also determined during the maturation of a primary myocyte culture, identifying 13 candidates from the subtractive cDNA libraries with putative roles in the myogenic program. During early stages of refeeding DNAJA4, HSPA1B, HSP90A, and CHAC1 expression increased, indicating activation of unfolded protein response pathways. Four genes were considered inhibitory to myogenesis based on their in vivo and in vitro expression profiles (CEBPD, ASB2, HSP30, novel transcript GE623928). Other genes showed increased expression with feeding and highest in vitro expression during the proliferative phase of the culture (FOXD1, DRG1) or as cells differentiated (SMYD1, RTN1, MID1IP1, HSP90A, novel transcript GE617747). The genes identified were associated with chromatin modification (SMYD1, RTN1), microtubule stabilization (MID1IP1), cell cycle regulation (FOXD1, CEBPD, DRG1), and negative regulation of signaling (ASB2) and may play a role in the stimulation of myogenesis during the transition from a catabolic to anabolic state in skeletal muscle.
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Affiliation(s)
- Neil I Bower
- Scottish Oceans Institute, School of Biology, University of St Andrews, St Andrews, Fife, United Kingdom.
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128
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Harada A, Okada S, Odawara J, Kumamaru H, Saiwai H, Aoki M, Nakamura M, Nishiyama Y, Ohkawa Y. Production of a rat monoclonal antibody specific for Myf5. Hybridoma (Larchmt) 2010; 29:59-62. [PMID: 20199153 DOI: 10.1089/hyb.2009.0066] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Myogenic regulatory factors (MRFs) are transcription factors that possess a characteristic basic helix-loop-helix domain. Myf5, MyoD, MRF4, and myogenin are well-known MRF family members that activate muscle-specific genes during differentiation. Myf5 is expressed first among MRFs at the very early phase and plays an important role in myoblast specificity and cell proliferation. Myf5 shares high homology with MyoD, and therefore some commercial Myf5 antibodies are cross-reactive for Myf5 and MyoD. To allow for detailed studies of the function of Myf5, we generated a monoclonal antibody specific for Myf5 utilizing a rat medial iliac lymph node method. Immunoblot analysis using our monoclonal antibody enabled us to identify Myf5 protein from rat myoblast L6E9 cell extract. Moreover, cell immunostaining revealed the nuclear localization of Myf5 in the L6E9 cells. This monoclonal antibody against Myf5 will allow us to perform further detailed studies of Myf5 and Myf5 function.
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Affiliation(s)
- Akihito Harada
- SSP Stem Cell Unit, Faculty of Medicine, Kyushu University , Fukuoka, Japan
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129
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Wang S, Guo L, Dong L, Guo L, Li S, Zhang J, Sun M. TGF-beta1 signal pathway may contribute to rhabdomyosarcoma development by inhibiting differentiation. Cancer Sci 2010; 101:1108-16. [PMID: 20219075 PMCID: PMC11158283 DOI: 10.1111/j.1349-7006.2010.01512.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Overexpression of transforming growth factor-beta1 (TGF-beta1) and its downstream molecules in the rhabdomyosarcoma (RMS) RD cell line has been reported previously, but the regulatory role of TGF-beta1 on RMS has not been studied extensively. In the present study, we showed that expression of TGF-beta1 and its downstream molecules type II TGF-beta receptor (TbetaRII) and Smad4 was significantly higher in RMS than in normal skeletal muscle, and there was a significant relationship between TGF-beta1 expression and histological grade. Gene silencing with TGF-beta1 short-hairpin RNA (shRNA)-expressing vectors significantly decreased the growth of RD cells, which was confirmed by caspase-3 (in vitro) and TUNEL (in vivo) assays. Moreover, a proportion of treated rhabdomyosarcoma (RD) cells changed to a round shape from the normal fusiform or polygonal shape and expressed myofilaments. Myogenin is one of the myogenic differentiation genes (MyoD) family of myogenic regulators, and was obviously higher in TGF-beta1-shRNA-treated tumors than it in control at the mRNA and protein level. Immunohistochemical staining with myogenic differentiation markers such as myosin and desmin in subcutaneous RMS tissue showed that TGF-beta1 shRNA increased staining for myosin. These results provide new insight into the biological function of TGF-beta1 in malignant tumors, and imply that the TGF-beta1 signal pathway is a potential therapeutic target for drugs that induce differentiation of RMS.
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Affiliation(s)
- Shouli Wang
- Department of Pathology, Soochow University School of Medicine, Suzhou, China.
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130
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Bower NI, Johnston IA. Paralogs of Atlantic salmon myoblast determination factor genes are distinctly regulated in proliferating and differentiating myogenic cells. Am J Physiol Regul Integr Comp Physiol 2010; 298:R1615-26. [PMID: 20375265 DOI: 10.1152/ajpregu.00114.2010] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The mRNA expression of myogenic regulatory factors, including myoD1 (myoblast determination factor) gene paralogs, and their regulation by amino acids and insulin-like growth factors were investigated in primary cell cultures isolated from fast myotomal muscle of Atlantic salmon (Salmo salar). The cell cycle and S phase were determined as 28.1 and 13.3 h, respectively, at 18 degrees C. Expression of myoD1b and myoD1c peaked at 8 days of culture in the initial proliferation phase and then declined more than sixfold as cells differentiated and was correlated with PCNA (proliferating cell nuclear antigen) expression (R = 0.88, P < 0.0001; R = 0.70, P < 0.0001). In contrast, myoD1a transcripts increased from 2 to 8 days and remained at elevated levels as myotubes were formed. mRNA levels of myoD1c were, on average, 3.1- and 5.7-fold higher than myoD1a and myoD1b, respectively. Depriving cells of amino acids and serum led to a rapid increase in pax7 and a decrease in myoD1c and PCNA expression, indicating a transition to a quiescent state. In contrast, amino acid replacement in starved cells produced significant increases in myoD1c (at 6 h), PCNA (at 12 h), and myoD1b (at 24 h) and decreases in pax7 expression as cells entered the cell cycle. Our results are consistent with temporally distinct patterns of myoD1c and myoD1b expression at the G(1) and S/G(2) phases of the cell cycle. Treatment of starved cells with insulin-like growth factor I or II did not alter expression of the myoD paralogs. It was concluded that, in vitro, amino acids alone are sufficient to stimulate expression of genes regulating myogenesis in myoblasts involving autocrine/paracrine pathways. The differential responses of myoD paralogs during myotube maturation and amino acid treatments suggest that myoD1b and myoD1c are primarily expressed in proliferating cells and myoD1a in differentiating cells, providing evidence for their subfunctionalization following whole genome and local duplications in the Atlantic salmon lineage.
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Affiliation(s)
- Neil I Bower
- Scottish Oceans Institute, School of Biology, University of St. Andrews, St. Andrews, Fife, United Kingdom.
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131
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Ontogenesis of muscle and adipose tissues and their interactions in ruminants and other species. Animal 2010; 4:1093-109. [DOI: 10.1017/s1751731110000601] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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132
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Fernandez-Fuente M, Ames EG, Wagner ML, Zhou H, Strom M, Zammit PS, Mickelson JR, Muntoni F, Brown SC, Piercy RJ. Assessment of the transformation of equine skin-derived fibroblasts to multinucleated skeletal myotubes following lentiviral-induced expression of equine myogenic differentiation 1. Am J Vet Res 2009; 69:1637-45. [PMID: 19046012 DOI: 10.2460/ajvr.69.12.1637] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To develop a reliable method for converting cultured equine skin-derived fibroblasts into muscle cells. SAMPLE POPULATION Equine skin-derived fibroblasts. PROCEDURES The equine myogenic differentiation 1 (eqMyoD) genomic sequence was obtained by use of equine bacterial artificial chromosome screening and PCR sequencing. Total mRNA was extracted from foal skeletal muscle, and eqMyoD cDNA was cloned into a plasmid vector with an internal ribosomal entry site to express bicistronic eqMyoD or enhanced green fluorescent protein (EGFP). Transient expression was confirmed by immunocytochemical analysis and western immunoblots in equine fibroblasts and fibroblasts from National Institutes of Health Swiss mouse embryos, prior to generation of a lentiviral vector containing the same coding sequences. Transformation of equine skin-derived cells into skeletal myotubes was examined by use of immunohistochemical analysis, western immunoblotting, and periodic acid-Schiff staining. RESULTS eqMyoD mRNA consists of 960 bp and shares high homology with myogenic differentiation 1 from other mammals. Transfection confirmed the expression of a 53-kd protein with mainly nuclear localization. Lentiviral transduction was efficient, with approximately 80% of EGFP-positive cells transformed into multinucleated myotubes during 15 days, as determined by expression of the muscle-specific proteins desmin, troponin-T, and sarcomeric myosin and by cytoplasmic storage of glycogen. CONCLUSIONS AND CLINICAL RELEVANCE Equine primary fibroblasts were transformed by lentiviral transduction of eqMyoD into fusion-competent myoblasts. This may offer a preferable alternative to primary myoblast cultures for the investigation of cellular defects associated with muscle diseases of horses, such as recurrent exertional rhabdomyolysis and polysaccharide storage myopathy.
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Affiliation(s)
- Marta Fernandez-Fuente
- Comparative Neuromuscular Diseases Laboratory, Department of Veterinary Clinical Sciences, Royal Veterinary College, Hawkshead Ln, Hertfordshire AL9 7TA, England
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133
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Guo Y, Bai J, Chang O, Lao H, Ye X, Luo J. Molecular structure of the largemouth bass (Micropterus salmoides) Myf5 gene and its effect on skeletal muscle growth. Mol Biol Rep 2009; 36:1497-504. [PMID: 18752038 PMCID: PMC2686805 DOI: 10.1007/s11033-008-9341-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2008] [Accepted: 08/12/2008] [Indexed: 11/28/2022]
Abstract
Myogenic Regulatory Factors (MRFs), a family of basic helix-loop-helix (bHLH) transcription factors, play important roles in regulating skeletal muscle development and growth. Myf5, the primary factor of MRFs, initiates myogenesis. Its expression pattern during somitomyogenesis in some fish has been revealed. To further study its effect on fish muscle during postembryonic growth, characterization and function analysis of myf5 cDNA were carried out in largemouth bass. The 1,093 bp cDNA sequence was identified by RT-PCR and 3'RACE, then the ORF of Myf5 cDNA was cloned into the expression vector pcDNA3.1(-)/mycHisB. The recombinant plasmid pcDNA3.1(-)/mycHisB-Myf5 was injected into the dorsal muscle of tilapias. RT-PCR and histochemical results showed that the exogenous gene was transcribed and translated in vivo. Its effect on muscle growth focused on myofiber hypertrophy in white muscle 60 days post injection. This indicated that overexpression of Myf5 can promote myogenesis during the fish muscle postembryonic growth period.
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Affiliation(s)
- Yuhan Guo
- Key Laboratory of Tropical & Subtropical Fish Breeding & Cultivation of Chinese Academy of Fisheries Sciences, Pearl River Fisheries Research Institute, CAFS, Guangzhou, 510380 China
- College of Aqua-Life Science and Technology, Shanghai Fisheries University, Shanghai, 200090 China
| | - Junjie Bai
- Key Laboratory of Tropical & Subtropical Fish Breeding & Cultivation of Chinese Academy of Fisheries Sciences, Pearl River Fisheries Research Institute, CAFS, Guangzhou, 510380 China
| | - Ouqin Chang
- Key Laboratory of Tropical & Subtropical Fish Breeding & Cultivation of Chinese Academy of Fisheries Sciences, Pearl River Fisheries Research Institute, CAFS, Guangzhou, 510380 China
| | - Haihua Lao
- Key Laboratory of Tropical & Subtropical Fish Breeding & Cultivation of Chinese Academy of Fisheries Sciences, Pearl River Fisheries Research Institute, CAFS, Guangzhou, 510380 China
| | - Xing Ye
- Key Laboratory of Tropical & Subtropical Fish Breeding & Cultivation of Chinese Academy of Fisheries Sciences, Pearl River Fisheries Research Institute, CAFS, Guangzhou, 510380 China
| | - Jianren Luo
- Key Laboratory of Tropical & Subtropical Fish Breeding & Cultivation of Chinese Academy of Fisheries Sciences, Pearl River Fisheries Research Institute, CAFS, Guangzhou, 510380 China
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134
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Lee JH, Bugarija B, Millan EJ, Walton NM, Gaetz J, Fernandes CJ, Yu WH, Mekel-Bobrov N, Vallender TW, Snyder GE, Xiang AP, Lahn BT. Systematic identification of cis-silenced genes by trans complementation. Hum Mol Genet 2008; 18:835-46. [PMID: 19050040 PMCID: PMC2640206 DOI: 10.1093/hmg/ddn409] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
A gene's transcriptional output is the combined product of two inputs: diffusible factors in the cellular milieu acting in trans, and chromatin state acting in cis. Here, we describe a strategy for dissecting the relative contribution of cis versus trans mechanisms to gene regulation. Referred to as trans complementation, it entails fusing two disparate cell types and searching for genes differentially expressed between the two genomes of fused cells. Any differential expression can be causally attributed to cis mechanisms because the two genomes of fused cells share a single homogenized milieu in trans. This assay uncovered a state of transcriptional competency that we termed 'occluded' whereby affected genes are silenced by cis-acting mechanisms in a manner that blocks them from responding to the trans-acting milieu of the cell. Importantly, occluded genes in a given cell type tend to include master triggers of alternative cell fates. Furthermore, the occluded state is maintained during cell division and is extraordinarily stable under a wide range of physiological conditions. These results support the model that the occlusion of lineage-inappropriate genes is a key mechanism of cell fate restriction. The identification of occluded genes by our assay provides a hitherto unavailable functional readout of chromatin state that is distinct from and complementary to gene expression status.
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Affiliation(s)
- Jae Hyun Lee
- Department of Human Genetics, Howard Hughes Medical Institute, University of Chicago, Chicago, IL 60637, USA
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135
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Shirinsky VP, Khapchaev AY, Stepanova OV. Molecular mechanisms of cardiomyogenesis and the prospects for cardiomyocyte regeneration in cardiac failure. Mol Biol 2008. [DOI: 10.1134/s0026893308050130] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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136
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Amabile G, D'Alise AM, Iovino M, Jones P, Santaguida S, Musacchio A, Taylor S, Cortese R. The Aurora B kinase activity is required for the maintenance of the differentiated state of murine myoblasts. Cell Death Differ 2008; 16:321-30. [PMID: 18974773 DOI: 10.1038/cdd.2008.156] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Reversine is a synthetic molecule capable of inducing dedifferentiation of C2C12, a murine myoblast cell line, into multipotent progenitor cells, which can be redirected to differentiate in nonmuscle cell types under appropriate conditions. Reversine is also a potent inhibitor of Aurora B, a protein kinase required for mitotic chromosome segregation, spindle checkpoint function, cytokinesis and histone H3 phosphorylation, raising the possibility that the dedifferentiation capability of reversine is mediated through the inhibition of Aurora B. Indeed, here we show that several other well-characterized Aurora B inhibitors are capable of dedifferentiating C2C12 myoblasts. Significantly, expressing drug-resistant Aurora B mutants, which are insensitive to reversine block the dedifferentiation process, indicating that Aurora B kinase activity is required to maintain the differentiated state. We show that the inhibition of the spindle checkpoint or cytokinesis per se is not sufficient for dedifferentiation. Rather, our data support a model whereby changes in histone H3 phosphorylation result in chromatin remodeling, which in turn restores the multipotent state.
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Affiliation(s)
- G Amabile
- CEINGE Biotecnologie Avanzate, Naples, Italy
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137
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Muir T, Wilson-Rawls J, Stevens JD, Rawls A, Schweitzer R, Kang C, Skinner MK. Integration of CREB and bHLH transcriptional signaling pathways through direct heterodimerization of the proteins: role in muscle and testis development. Mol Reprod Dev 2008; 75:1637-52. [PMID: 18361414 DOI: 10.1002/mrd.20902] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The cAMP response element binding protein/activating transcription factor (CREB/ATF) family of transcription factors is hormone responsive and critical for nearly all mammalian cell types. The basic helix-loop-helix (bHLH) family of transcription factors is important during the development and differentiation of a wide variety of cell types. Independent studies of the role of the bHLH protein scleraxis in testicular Sertoli cells and paraxis in muscle development using yeast-2-hybrid screens provided the novel observation that bHLH proteins can directly interact with ATF/CREB family members. Analysis of the interactions demonstrated the helix-loop-helix domain of bHLH proteins directly interacts with the leucine zipper (ZIP) region of CREB2/ATF4 to form heterodimers. The direct bHLH-CREB2 binding interactions were supported using co-immunoprecipitation of recombinant proteins. Structural analysis of bHLH and ATF4 heterodimer using previous crystal structures demonstrated the heterodimer likely involves the HLH and Zip domains and has the potential capacity to bind DNA. Transfection assays demonstrated CREB2/ATF4 over-expression blocked stimulatory actions of scleraxis or paraxis. CREB1 inhibited MyoD induced myogenic conversion of C3H10T1/2 cells. CREB2/ATF4 and scleraxis are expressed throughout embryonic and postnatal testis development, with scleraxis specifically expressed in Sertoli cells. ATF4 and scleraxis null mutant mice both had similar adult testis phenotypes of reduced spermatogenic capacity. In summary, bHLH and CREB family members were found to directly heterodimerize and inhibit the actions of bHLH dimers on Sertoli cells and myogenic precursor cells. The observations suggest a mechanism for direct cross-talk between cAMP induced and bHLH controlled cellular differentiation.
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Affiliation(s)
- Tera Muir
- Center for Reproductive Biology, Washington State University, Pullman, Washington 99164-4231, USA
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138
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Liu M, Peng J, Xu DQ, Zheng R, Li FE, Li JL, Zuo B, Lei MG, Xiong YZ, Deng CY, Jiang SW. Association of MYF5 and MYOD1 Gene Polymorphisms and Meat Quality Traits in Large White × Meishan F2 Pig Populations. Biochem Genet 2008; 46:720-32. [DOI: 10.1007/s10528-008-9187-1] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2007] [Accepted: 05/30/2008] [Indexed: 10/21/2022]
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139
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Yamaguchi Y, Oohinata R, Naiki T, Irie K. Stau1 negatively regulates myogenic differentiation in C2C12 cells. Genes Cells 2008; 13:583-92. [PMID: 18422603 DOI: 10.1111/j.1365-2443.2008.01189.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Sequential expression of myogenic regulatory factors (MRFs) such as MyoD and myogenin drives myogenic differentiation. Besides transcriptional activation of MRFs, this process is also coordinated by post-transcriptional regulation; MyoD and myogenin mRNAs are stabilized by RNA-binding protein HuR. Stau1 is known to regulate mRNA stability in a complex with Upf1, which is termed Stau1-mediated mRNA decay (SMD). We describe here that Stau1 is involved in the regulation of myogenesis. We found that knockdown of Stau1 promotes myogenesis including the expression of a muscle-specific marker protein, myoglobin, in C2C12 myoblasts. MyoD induces myogenin expression in response to induction of myogenesis, which is a key step to start myogenesis. The level of MyoD protein was not affected when Stau1 was depleted by siRNA, whereas the levels of myogenin mRNA and protein were increased in Stau1-knockdown cells. Interestingly, myogenin promoter activity was also increased in Stau1-knockdown cells in the absence of induction of myogenesis. Furthermore, Stau1-knockdown cells spontaneously progressed myogenesis including the expression of muscle-specific protein. Although Stau1 is involved in mRNA decay together with Upf1, Upf1-knockdown did not affect progression of myogenesis. Our results suggest that Stau1 negatively regulates myogenesis in C2C12 myoblasts through a mechanism that is different from SMD.
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Affiliation(s)
- Yukio Yamaguchi
- Department of Molecular Cell Biology, Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tennoudai 1-1-1, Tsukuba, Ibaraki 305-8575, Japan
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140
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Falcone G, Gauzzi MC, Tatò F, Alemà S. Differential control of muscle-specific gene expression specified by src and myc oncogenes in myogenic cells. CIBA FOUNDATION SYMPOSIUM 2007; 150:250-8; discussion 258-61. [PMID: 2115425 DOI: 10.1002/9780470513927.ch15] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Myogenic cells can be transformed in vitro by the introduction of several exogenous viral oncogenes. Transformed myoblasts are prevented from terminal differentiation into myotubes by the continuous expression of oncogenes such as myc and src, chosen as prototypes of nuclear and cytoplasmic oncogenes. A comparative analysis of the relationship between transformation and differentiation in myoblasts and cells belonging to other lineages has led to the proposal that terminal differentiation of myc-transformed quail myoblasts is indirectly prevented by the loss of growth control and that myc-bearing cells remain susceptible to growth regulation by interaction with adjacent normal cells. On the contrary, the src oncogene appears to affect expression of the myogenic programme via a direct mechanism, independent from abnormal growth control. There is increasing evidence for the existence of master regulatory genes that govern and influence muscle development in vivo and myogenic differentiation in vitro. Expression of cytoplasmic oncogenes such as src, ras and polyoma middle T in the mouse myogenic cell line, C2, results in inhibition of biochemical differentiation and a marked down-regulation of the MyoD1 and myogenin genes.
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Affiliation(s)
- G Falcone
- Istituto di Biologia Cellulare, C.N.R., Roma, Italy
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141
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Buckingham ME, Lyons GE, Ott MO, Sassoon DA. Myogenesis in the mouse. CIBA FOUNDATION SYMPOSIUM 2007; 165:111-24; discussion 124-31. [PMID: 1516464 DOI: 10.1002/9780470514221.ch7] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The first striated muscle to form during mouse embryogenesis is the heart followed by skeletal muscle which is derived from the somites. The expression of genes encoding muscle structural proteins and myogenic regulatory sequences of the MyoD1 family has been examined using 35S-labelled riboprobes. In the cardiac tube, actin and myosin genes are expressed together from an early stage, whereas in the myotome, the earliest skeletal muscle, they are activated asynchronously over days. They are not expressed in the somite prior to myotome formation. One potential muscle marker, carbonic anhydrase III, is expressed in early mesoderm and subsequently in the notochord, similarly to the Brachyury gene. The myogenic sequences are not detectable in the heart. In the myotome they show distinct patterns of expression; this is discussed in the context of their role as muscle transcription factors. myf-5 is the only myogenic factor sequence present in the somite prior to muscle formation and thus is potentially involved in an earlier step of muscle determination. It is also present in the early limb bud, but the status of myogenic precursor cells in the limb in this context is less clear.
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Affiliation(s)
- M E Buckingham
- Department of Molecular Biology, CNRS URA 1148, Pasteur Institute, Paris, France
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142
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Laursen KB, Mielke E, Iannaccone P, Füchtbauer EM. Mechanism of transcriptional activation by the proto-oncogene Twist1. J Biol Chem 2007; 282:34623-33. [PMID: 17893140 DOI: 10.1074/jbc.m707085200] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Mammalian Twist1, a master regulator in development and a key factor in tumorigenesis, is known to repress transcription by several mechanisms and is therefore considered to mediate its function mainly through inhibition. A role of Twist1 as transactivator has also been reported but, so far, without providing a mechanism for such an activity. Here we show that heterodimeric complexes of Twist1 and E12 mediate E-box-dependent transcriptional activation. We identify a novel Twist1 transactivation domain that coactivates together with the less potent E12 transactivation domain. We found three specific residues in the highly conserved WR domain to be essential for the transactivating function of murine Twist1 and suggest an alpha-helical structure of the transactivation domain.
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143
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Washabaugh CH, Ontell MP, Shand SH, Bradbury N, Kant JA, Ontell M. Neuronal control of myogenic regulatory factor accumulation in fetal muscle. Dev Dyn 2007; 236:732-45. [PMID: 17295338 DOI: 10.1002/dvdy.21078] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
The lumbosacral spinal cords of 14.5-day gestation mice (E14.5) were ablated. The number of molecules of each of the four myogenic regulatory factor (MRF) mRNAs per nanogram of total RNA were evaluated in innervated and aneural fetal crural muscles. Accumulation of all four MRF mRNAs was affected in aneural muscle, but was never more than threefold different than in innervated muscles, considerably less than after adult denervation. The effect of the nerve varied with the MRF, the fetal age, and with the muscle (extensor digitorum longus muscle [EDL] vs. soleus muscle), with the nerve having multiple effects including down-regulation of certain MRF genes at specific periods (e.g., myoD and myogenin [E16.5-E18.5] and MRF4 in the EDL only [E18.5-E19.5]); limiting the up-regulation of certain genes, which occurred in the absence of innervation (e.g., myf-5 [E18.5-E19.5] and myogenin [E14.5-E16.5]); and even enhancing the accumulation of MRF4 mRNA (E14.5-E16.5). We hypothesize that factors other than nerve contribute to the down-regulation of myf-5 and myogenin mRNAs to adult levels. Innervation was required for the emergence of the slow, but not the fast, MRF mRNA profile at birth. MyoD, found in both the nuclear and cytoplasmic protein extracts of innervated fetal muscle, increased by approximately 5-fold in the nuclear extracts (approximately 2.5-fold in the cytoplasmic) of E19.5 aneural muscles, significantly less than the 12-fold increase found in the nuclear extract of 4-day denervated adult muscle. This increase in aneural fetal muscle was due primarily to an increased concentration of myoD in muscle lineage nuclei, rather than to the presence of additional myoD(+) muscle lineage nuclei.
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Affiliation(s)
- Charles H Washabaugh
- Department of Cell Biology and Physiology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
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144
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Xu P, Tan X, Zhang Y, Zhang PJ, Xu Y. Cloning and expression analysis of myogenin from flounder (Paralichthys olivaceus) and promoter analysis of muscle-specific expression. Comp Biochem Physiol B Biochem Mol Biol 2007; 147:135-45. [PMID: 17336560 DOI: 10.1016/j.cbpb.2007.01.012] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2006] [Revised: 01/07/2007] [Accepted: 01/08/2007] [Indexed: 01/26/2023]
Abstract
Myogenin is a bHLH transcription factor of the MyoD family. It plays a crucial role in myoblast differentiation and maturation. We report here the isolation of flounder myogenin gene and the characterization of its expression patterns. Sequence analysis indicated that flounder myogenin shared a similar structure and the conserved bHLH domain with other vertebrate myogenin genes. Flounder myogenin gene contains 3 exons and 2 introns. Sequence alignment and phylogenetic showed that flounder myogenin was more homologous with halibut (Hippoglossus hippoglossus) myogenin and striped bass (Morone saxatilis) myogenin. Whole-mount embryo in situ hybridization revealed that flounder myogenin was first detected in the medial region of somites that give rise to slow muscles, and expanded later to the lateral region of the somite that become fast muscles. The levels of myogenin transcripts dropped significantly in matured somites at the trunk region. Its expression could only be detected in the caudal somites, which was consistent with the timing of somite maturation. Transient expression analysis showed that the 546 bp flounder myogenin promoter was sufficient to direct muscle-specific GFP expression in zebrafish embryos.
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Affiliation(s)
- Peng Xu
- Institute of Oceanology, Chinese Academy of Sciences, Qingdao, PR China
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145
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Scuoppo C, Riess I, Schmitt-Ney M, Allegra P, Forni PE, Bersani F, Taulli R, Accornero P, Crepaldi T, Ponzetto C. The oncogenic transcription factor PAX3-FKHR can convert fibroblasts into contractile myotubes. Exp Cell Res 2007; 313:2308-17. [PMID: 17490646 DOI: 10.1016/j.yexcr.2007.02.037] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2006] [Revised: 02/15/2007] [Accepted: 02/15/2007] [Indexed: 01/16/2023]
Abstract
PAX3-FKHR, the product of a rearrangement of PAX3 with FKHR is the pathogenetic marker for alveolar rhabdomyosarcoma, an aggressive form of childhood cancer. In this work we show that PAX3-FKHR, which is a stronger transcriptional activator relative to PAX3, can lead to two apparently irreconcilable outcomes: transformation and terminal myogenic differentiation. Fibroblasts (10T1/2, NIH3T3, and a newly established murine line named 'Plus') transduced by PAX3-FKHR acquire transformed features such as anchorage independence and loss of contact inhibition and concomitantly undergo various degrees of myogenic conversion depending on the host cells, including, in the case of the Plus line, terminal differentiation into contractile myotubes. This work highlights the potential of PAX3-FKHR to functionally operate as a deregulated Pangene and may have implications with regard to the identity of the precursor cell giving rise to alveolar rhabdomyosarcoma.
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Affiliation(s)
- Claudio Scuoppo
- Center for Experimental Research and Medical Studies (CeRMS), Molinette Hospital, Turin, Italy
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146
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Li X, Zhu L, Chen X, Fan M. Effects of hypoxia on proliferation and differentiation of myoblasts. Med Hypotheses 2007; 69:629-36. [PMID: 17395396 DOI: 10.1016/j.mehy.2006.12.050] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2006] [Accepted: 12/18/2006] [Indexed: 02/09/2023]
Abstract
Oxygen is an environmental and developmental signal regulator, and its role is involved in energy homeostasis, development and process of differentiation. Myoblasts persist in skeletal muscle as satellite cells, which possess capability of self-renewing and differentiation into mature myofiber. Myoblasts play a critical role in postnatal muscle regeneration after injury as well as maintaining myofibers' function. Though oxygen is vital to nearly all forms of life, studies focused on investigating the effects of oxygen level on proliferation and differentiation of myoblasts are few. Lower oxygen concentration is more close to the level of oxygen in physiological and pathological environment in vivo. So physiological environment is actually optimum condition for myogenesis. It is significant for understanding repair and regeneration of skeletal muscle to study on effects of hypoxia on myogenesis. HIF-1 signaling pathway was involved in these processes as well as other signaling pathways would be, and accordingly, deep studying and further revealing the signaling pathways involved in mechanism will provide evidences or references for looking for novel targets for stem cells therapy and drug treatment.
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Affiliation(s)
- Xiang Li
- Institute of Basic Medical Sciences, 27 Taiping Road, Beijing 100850, China
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147
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Cooper ST, Kizana E, Yates JD, Lo HP, Yang N, Wu ZH, Alexander IE, North KN. Dystrophinopathy carrier determination and detection of protein deficiencies in muscular dystrophy using lentiviral MyoD-forced myogenesis. Neuromuscul Disord 2007; 17:276-84. [PMID: 17303423 DOI: 10.1016/j.nmd.2006.12.010] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2006] [Revised: 12/12/2006] [Accepted: 12/16/2006] [Indexed: 11/26/2022]
Abstract
The objective of this study is to expand the applications of MyoD-forced myogenesis for research and diagnosis of human muscle disorders using a lentiviral vector (LVhMyoD) for efficient trans-differentiation of patient primary cells. LVhMyoD transduced cells readily formed striated, multinucleate myotubes expressing a wide range of genes associated with muscular dystrophy (dystrophin, dysferlin, sarcoglycans, caveolin-3) and congenital myopathy (nebulin, actin, desmin, tropomyosin, troponin). We demonstrate that MyoD gene-modified fibroblasts reproduce protein deficiencies associated with different forms of muscular dystrophy, and confirm that LVhMyoD gene-modified chorionic villus can be used successfully to determine the dystrophin status of the developing fetus, augmenting prenatal diagnosis of dystrophinopathy patients. Using muscle-specific cDNA derived from LVhMyoD gene-modified patient cells, we identified a female carrier bearing a large dystrophin deletion and a previously unidentified non-coding splice-site mutation within dystrophin in a Becker muscular dystrophy patient. This study highlights the significant potential of lentiviral MyoD-forced myogenesis for study of a wide range of human muscle disorders; a field constrained by the limited availability of human tissue. LVhMyoD gene-modified patient cells provide a renewable source of mutant protein and muscle-specific mRNA, facilitating accelerated mutation screening of large genes, molecular analyses of splicing abnormalities and study of disease-causing mutations.
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Affiliation(s)
- Sandra T Cooper
- Neurogenetics Research Unit and Institute for Neuromuscular Research, The Children's Hospital at Westmead, Locked Bag 4001, Sydney, NSW 2145, Australia.
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148
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Pillitteri LJ, Torii KU. Breaking the silence: three bHLH proteins direct cell-fate decisions during stomatal development. Bioessays 2007; 29:861-70. [PMID: 17691100 DOI: 10.1002/bies.20625] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Stomata are microscopic pores on the surface of land plants used for gas and water vapor exchange. A pair of highly specialized guard cells surround the pore and adjust pore size. Studies in Arabidopsis have revealed that cell-cell communication is essential to coordinate the asymmetric cell divisions required for proper stomatal patterning. Initial research in this area identified signaling molecules that negatively regulate stomatal differentiation. However, genes promoting cell-fate transition leading to mature guard cells remained elusive. Now, three closely related basic helix-loop-helix (bHLH) proteins, SPEECHLESS, MUTE and FAMA have been identified as positive regulators that direct three consecutive cell-fate decisions during stomatal development. The identification of these genes opens a new direction to investigate the evolution of stomatal development and the conserved functions of bHLH proteins in cell type differentiation adopted by plants and animals.
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149
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Grossi A, Yadav K, Lawson MA. Mechanical stimulation increases proliferation, differentiation and protein expression in culture: Stimulation effects are substrate dependent. J Biomech 2007; 40:3354-62. [PMID: 17582421 DOI: 10.1016/j.jbiomech.2007.05.007] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2004] [Revised: 05/07/2007] [Accepted: 05/08/2007] [Indexed: 10/23/2022]
Abstract
Myogenesis is a complex sequence of events, including the irreversible transition from the proliferation-competent myoblast stage into fused, multinucleated myotubes. Myogenic differentiation is regulated by positive and negative signals from surrounding tissues. Stimulation due to stretch- or load-induced signaling is now beginning to be understood as a factor which affects various signal transduction pathways, gene sequences and protein synthesis. One indication of which cells are competent to undergo the fusion process is their expression of two proteins, Myo-D and myogenin. The mechanism by which the cells are able to to regulate Myo-D and myogenin is poorly understood. In the present work, we investigate the role of mechanical loading, through specific receptors to intracellular matrix proteins such as laminin and fibronectin, in both Myo-D and myogenin expression in C(2)C(12) cells. We propose to elucidate also the signaling pathway by which this mechanical stimulation can causes an increase in protein expression. When mechanically stimulated via laminin receptors on cell surface, C(2)C(12) cells showed an increase in cell proliferation and differentiation. Populations undergoing mechanical stimulation through laminin receptors show an increase in expression of Myo-D, myogenin and an increase in ERK1/2 phosphorylation. Cells stimulated via fibronectin receptors show no significant increases in fusion competence. We conclude that load induced signalling through integrin containing laminin recepotors plays a role in myoblast differentiation and fusion.
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Affiliation(s)
- Alberto Grossi
- Department of Food Science, The Royal Veterinary and Agricultural University, DK-1958 Frederiksberg C, Denmark
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150
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Liu M, Peng J, Xu DQ, Zheng R, Li FE, Li JL, Zuo B, Lei MG, Xiong YZ, Deng CY, Jiang SW. Association analyses of polymorphisms in porcine MYF5 and MYOD1 genes with carcass traits. ACTA ACUST UNITED AC 2007. [DOI: 10.1071/ar06420] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The objective of this study was to assess the effect of polymorphisms of myogenic factor 5 (MYF5) and myogenic differentiation 1 (MYOD1) genes on carcass traits in pigs. PCR-RFLP was used to identify three and one SNP(s) from the MYF5 and the MYOD1 gene, respectively. Association analysis performed on the four polymorphisms in a series of three Large White × Meishan F2 populations totalling near 400 pigs showed: (1) an MYF5 exon 1 Hsp92II polymorphism causing a Met→Leu substitution was significantly associated with fat meat percentage, shoulder fat thickness, thorax-waist fat thickness, average backfat thickness and carcass length to 1st rib (P < 0.05); (2) an MYF5 exon 2 MspI polymorphism and an intron 1 HaeIII polymorphism, which were completely linked, were significantly associated with thorax-waist fat thickness, 6–7th rib fat thickness and carcass length to 1st rib (P < 0.05); (3) an MYOD1 intron 1 DdeI polymorphism was significantly associated with carcass length to 1st rib.
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