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Christensen DL, Mutabingwa TK, Bygbjerg IC, Vaag AA, Grunnet LG, Lajeunesse-Trempe F, Nielsen J, Schmiegelow C, Ramaiya KL, Myburgh KH. Skeletal muscle fibre type and enzymatic activity in adult offspring following placental and peripheral malaria exposure in foetal life. Front Public Health 2023; 11:1122393. [PMID: 37333553 PMCID: PMC10275361 DOI: 10.3389/fpubh.2023.1122393] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Accepted: 05/12/2023] [Indexed: 06/20/2023] Open
Abstract
Background Maternal malaria may restrict foetal growth. Impaired utero-placental blood flow due to malaria infection may cause hypoxia-induced altered skeletal muscle fibre type distribution in the offspring, which may contribute to insulin resistance and impaired glucose metabolism. This study assessed muscle fibre distribution 20 years after placental and/or peripheral in-utero malaria exposure compared to no exposure, i.e., PPM+, PM+, and M-, respectively. Methods We traced 101 men and women offspring of mothers who participated in a malaria chemosuppression study in Muheza, Tanzania. Of 76 eligible participants, 50 individuals (29 men and 21 women) had skeletal muscle biopsy taken from m. vastus lateralis in the right leg. As previously reported, fasting and 30 min post-oral glucose challenge plasma glucose values were higher, and insulin secretion disposition index was lower, in the PPM+ group. Aerobic capacity (fitness) was estimated by an indirect VO2max test on a stationary bicycle. Muscle fibre sub-type (myosin heavy chain, MHC) distribution was analysed, as were muscle enzyme activities (citrate synthase (CS), 3-hydroxyacyl-CoA dehydrogenase, myophosphorylase, phosphofructokinase, lactate dehydrogenase, and creatine kinase activities. Between-group analyses were adjusted for MHC-I %. Results No differences in aerobic capacity were found between groups. Despite subtle elevations of plasma glucose levels in the PPM+ group, there was no difference in MHC sub-types or muscle enzymatic activities between the malaria-exposed and non-exposed groups. Conclusion The current study did not show differences in MHC towards glycolytic sub-types or enzymatic activity across the sub-groups. The results support the notion of the mild elevations of plasma glucose levels in people exposed to placental malaria in pregnancy being due to compromised pancreatic insulin secretion rather than insulin resistance.
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Affiliation(s)
| | | | - Ib C. Bygbjerg
- Department of Public Health, University of Copenhagen, Copenhagen, Denmark
- Department of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark
| | - Allan A. Vaag
- Department of Clinical Sciences, Lund University, Lund, Sweden
- Translational Type 2 Diabetes Research, Steno Diabetes Center Copenhagen, Herlev, Denmark
| | - Louise G. Grunnet
- Department of Public Health, University of Copenhagen, Copenhagen, Denmark
- Clinical Prevention Research, Steno Diabetes Center Copenhagen, Herlev, Denmark
| | | | - Jannie Nielsen
- Department of Public Health, University of Copenhagen, Copenhagen, Denmark
| | | | | | - Kathryn H. Myburgh
- Department of Physiological Sciences, Stellenbosch University, Stellenbosch, South Africa
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Innocenzi E, Cariati I, De Domenico E, Tiberi E, D'Arcangelo G, Verdile V, Paronetto MP, Tancredi V, Barchi M, Rossi P, Sette C, Grimaldi P. Aerobic Exercise Induces Alternative Splicing of Neurexins in Frontal Cortex. J Funct Morphol Kinesiol 2021; 6. [PMID: 34072692 DOI: 10.3390/jfmk6020048] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Revised: 05/24/2021] [Accepted: 05/26/2021] [Indexed: 12/02/2022] Open
Abstract
Aerobic exercise (AE) is known to produce beneficial effects on brain health by improving plasticity, connectivity, and cognitive functions, but the underlying molecular mechanisms are still limited. Neurexins (Nrxns) are a family of presynaptic cell adhesion molecules that are important in synapsis formation and maturation. In vertebrates, three-neurexin genes (NRXN1, NRXN2, and NRXN3) have been identified, each encoding for α and β neurexins, from two independent promoters. Moreover, each Nrxns gene (1-3) has several alternative exons and produces many splice variants that bind to a large variety of postsynaptic ligands, playing a role in trans-synaptic specification, strength, and plasticity. In this study, we investigated the impact of a continuous progressive (CP) AE program on alternative splicing (AS) of Nrxns on two brain regions: frontal cortex (FC) and hippocampus. We showed that exercise promoted Nrxns1-3 AS at splice site 4 (SS4) both in α and β isoforms, inducing a switch from exon-excluded isoforms (SS4-) to exon-included isoforms (SS4+) in FC but not in hippocampus. Additionally, we showed that the same AE program enhanced the expression level of other genes correlated with synaptic function and plasticity only in FC. Altogether, our findings demonstrated the positive effect of CP AE on FC in inducing molecular changes underlying synaptic plasticity and suggested that FC is possibly a more sensitive structure than hippocampus to show molecular changes.
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Baig MH, Rashid I, Srivastava P, Ahmad K, Jan AT, Rabbani G, Choi D, Barreto GE, Ashraf GM, Lee EJ, Choi I. NeuroMuscleDB: a Database of Genes Associated with Muscle Development, Neuromuscular Diseases, Ageing, and Neurodegeneration. Mol Neurobiol 2019; 56:5835-5843. [PMID: 30684219 DOI: 10.1007/s12035-019-1478-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Accepted: 01/10/2019] [Indexed: 12/25/2022]
Abstract
Skeletal muscle is a highly complex, heterogeneous tissue that serves a multitude of biological functions in living organisms. With the advent of methods, such as microarrays, transcriptome analysis, and proteomics, studies have been performed at the genome level to gain insight of changes in the expression profiles of genes during different stages of muscle development and of associated diseases. In the present study, a database was conceived for the straightforward retrieval of information on genes involved in skeletal muscle formation, neuromuscular diseases (NMDs), ageing, and neurodegenerative disorders (NDs). The resulting database named NeuroMuscleDB ( http://yu-mbl-muscledb.com/NeuroMuscleDB ) is the result of a wide literature survey, database searches, and data curation. NeuroMuscleDB contains information of genes in Homo sapiens, Mus musculus, and Bos Taurus, and their promoter sequences and specified roles at different stages of muscle development and in associated myopathies. The database contains information on ~ 1102 genes, 6030 mRNAs, and 5687 proteins, and embedded analytical tools that can be used to perform tasks related to gene sequence usage. The authors believe NeuroMuscleDB provides a platform for obtaining desired information on genes related to myogenesis and their associations with various diseases (NMDs, ageing, and NDs). NeuroMuscleDB is freely available on the web at http://yu-mbl-muscledb.com/NeuroMuscleDB and supports all major browsers.
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Affiliation(s)
- Mohammad Hassan Baig
- Department of Medical Biotechnology, Yeungnam University, Gyeongsan, 38541, Republic of Korea
| | - Iliyas Rashid
- Amity Institute of Biotechnology, Amity University, Lucknow, Uttar Pradesh, 226 028, India
| | - Prachi Srivastava
- Amity Institute of Biotechnology, Amity University, Lucknow, Uttar Pradesh, 226 028, India
| | - Khurshid Ahmad
- Department of Medical Biotechnology, Yeungnam University, Gyeongsan, 38541, Republic of Korea
| | - Arif Tasleem Jan
- School of Biosciences and Biotechnology, Baba Ghulam Shah Badshah University, Rajouri, 185236, India
| | - Gulam Rabbani
- Department of Medical Biotechnology, Yeungnam University, Gyeongsan, 38541, Republic of Korea
| | - Dukhwan Choi
- Department of Medical Biotechnology, Yeungnam University, Gyeongsan, 38541, Republic of Korea
| | - George E Barreto
- Departamento de Nutrición y Bioquímica, Facultad de Ciencias, Pontificia Universidad Javeriana, Bogotá D.C., Colombia.,Instituto de Ciencias Biomédicas, Universidad Autónoma de Chile, Santiago, Chile
| | - Ghulam Md Ashraf
- King Fahd Medical Research Center, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Eun Ju Lee
- Department of Medical Biotechnology, Yeungnam University, Gyeongsan, 38541, Republic of Korea.
| | - Inho Choi
- Department of Medical Biotechnology, Yeungnam University, Gyeongsan, 38541, Republic of Korea.
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Ahn JS, Kim DH, Park HB, Han SH, Hwang S, Cho IC, Lee JW. Ectopic Overexpression of Porcine Myh1 Increased in Slow Muscle Fibers and Enhanced Endurance Exercise in Transgenic Mice. Int J Mol Sci 2018; 19:ijms19102959. [PMID: 30274168 PMCID: PMC6213911 DOI: 10.3390/ijms19102959] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Revised: 09/19/2018] [Accepted: 09/26/2018] [Indexed: 11/23/2022] Open
Abstract
Myosin heavy chain (MyHC) isoforms consist of Myh7, Myh2, Myh1, and Myh4, which are expressed in skeletal muscle tissues during postnatal development. These genes influence the contraction–relaxation activity in skeletal muscles and are involved in determining muscle composition such as the proportion of fast-to-slow and/or slow-to-fast fiber types. Among them, Myh1 is associated with skeletal muscle contraction and is involved in both slow-to-fast and fast-to-slow transition. However, the muscle transition mechanism is not well understood. For this study, we first produced porcine Myh1 transgenic (TG) mice to study whether the ectopic expressed porcine Myh1 gene had any effects on muscle composition, especially on slow-type muscle components. Our results showed that the factors associated with slow muscles, such as Myh7, Myoglobin, Troponin (slow-type units), and cytochrome C, were highly expressed in the quadriceps muscles of Myh1 transgenic mice. Furthermore, the ectopic porcine MYH1 protein was located only in the slow-type muscle fibers of the quadriceps muscles in Myh1 transgenic mice. In physical endurance tests, Myh1 transgenic mice ran longer and further on a treadmill than wild-type (WT) mice. These data fully supported our hypothesis that Myh1 is associated with slow muscle composition, with overexpression of Myh1 in muscle tissues possibly being a new key in modulating muscle fiber types. Our study provides a better understanding of muscle composition metabolism, physical mobility, and genetic factors in muscle fatigue.
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Affiliation(s)
- Jin Seop Ahn
- Biotherapeutics Translational Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon 34141, Korea.
| | - Dong-Hwan Kim
- Biotherapeutics Translational Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon 34141, Korea.
- Department of Functional Genomics, University of Science and Technology, Daejeon 34113, Korea.
| | - Hee-Bok Park
- Subtropical Livestock Research Institute, National Institute of Animal Science, Jeju 63242, Korea.
| | - Sang-Hyun Han
- Educational Science Research Institute, Jeju National University, Jeju 63243, Korea.
| | - Seongsoo Hwang
- Animal Biotechnology Division, National Institute of Animal Science, Wanju 55365, Korea.
| | - In-Cheol Cho
- Animal Genetics and Bioinformatics Division, National Institute of Animal Science, Wanju 55365, Korea.
| | - Jeong-Woong Lee
- Biotherapeutics Translational Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon 34141, Korea.
- Department of Functional Genomics, University of Science and Technology, Daejeon 34113, Korea.
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Shi H, Munk A, Nielsen TS, Daughtry MR, Larsson L, Li S, Høyer KF, Geisler HW, Sulek K, Kjøbsted R, Fisher T, Andersen MM, Shen Z, Hansen UK, England EM, Cheng Z, Højlund K, Wojtaszewski JFP, Yang X, Hulver MW, Helm RF, Treebak JT, Gerrard DE. Skeletal muscle O-GlcNAc transferase is important for muscle energy homeostasis and whole-body insulin sensitivity. Mol Metab 2018. [PMID: 29525407 PMCID: PMC6001359 DOI: 10.1016/j.molmet.2018.02.010] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Objective Given that cellular O-GlcNAcylation levels are thought to be real-time measures of cellular nutrient status and dysregulated O-GlcNAc signaling is associated with insulin resistance, we evaluated the role of O-GlcNAc transferase (OGT), the enzyme that mediates O-GlcNAcylation, in skeletal muscle. Methods We assessed O-GlcNAcylation levels in skeletal muscle from obese, type 2 diabetic people, and we characterized muscle-specific OGT knockout (mKO) mice in metabolic cages and measured energy expenditure and substrate utilization pattern using indirect calorimetry. Whole body insulin sensitivity was assessed using the hyperinsulinemic euglycemic clamp technique and tissue-specific glucose uptake was subsequently evaluated. Tissues were used for histology, qPCR, Western blot, co-immunoprecipitation, and chromatin immunoprecipitation analyses. Results We found elevated levels of O-GlcNAc-modified proteins in obese, type 2 diabetic people compared with well-matched obese and lean controls. Muscle-specific OGT knockout mice were lean, and whole body energy expenditure and insulin sensitivity were increased in these mice, consistent with enhanced glucose uptake and elevated glycolytic enzyme activities in skeletal muscle. Moreover, enhanced glucose uptake was also observed in white adipose tissue that was browner than that of WT mice. Interestingly, mKO mice had elevated mRNA levels of Il15 in skeletal muscle and increased circulating IL-15 levels. We found that OGT in muscle mediates transcriptional repression of Il15 by O-GlcNAcylating Enhancer of Zeste Homolog 2 (EZH2). Conclusions Elevated muscle O-GlcNAc levels paralleled insulin resistance and type 2 diabetes in humans. Moreover, OGT-mediated signaling is necessary for proper skeletal muscle metabolism and whole-body energy homeostasis, and our data highlight O-GlcNAcylation as a potential target for ameliorating metabolic disorders. Type 2 diabetic humans have elevated O-GlcNAc levels in skeletal muscle. Knockout of OGT in muscle elevates whole body insulin sensitivity. Knockout of OGT in muscle increases resistance to diet-induced obesity. Muscle-specific OGT knockout mice have elevated plasma IL-15 levels. OGT in muscle controls Il15 expression by O-GlcNAcylation and inhibition of EZH2.
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Affiliation(s)
- Hao Shi
- Department of Animal and Poultry Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA
| | - Alexander Munk
- Section of Integrative Physiology, Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, DK2200, Denmark
| | - Thomas S Nielsen
- Section of Integrative Physiology, Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, DK2200, Denmark
| | - Morgan R Daughtry
- Department of Animal and Poultry Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA
| | - Louise Larsson
- Section of Integrative Physiology, Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, DK2200, Denmark
| | - Shize Li
- Department of Animal and Poultry Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA
| | - Kasper F Høyer
- Section of Integrative Physiology, Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, DK2200, Denmark; Department of Endocrinology and Internal Medicine, Aarhus University Hospital, Aarhus, DK8000, Denmark
| | - Hannah W Geisler
- Department of Animal and Poultry Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA
| | - Karolina Sulek
- Section of Integrative Physiology, Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, DK2200, Denmark
| | - Rasmus Kjøbsted
- Section of Molecular Physiology, Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, Copenhagen, DK2100, Denmark
| | - Taylor Fisher
- Department of Animal and Poultry Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA
| | - Marianne M Andersen
- Section of Integrative Physiology, Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, DK2200, Denmark
| | - Zhengxing Shen
- Department of Animal and Poultry Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA
| | - Ulrik K Hansen
- Section of Integrative Physiology, Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, DK2200, Denmark
| | - Eric M England
- Department of Animal and Poultry Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA
| | - Zhiyong Cheng
- Department of Human Nutrition, Foods, and Exercise, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA
| | - Kurt Højlund
- Department of Endocrinology, Odense University Hospital, Odense, Denmark; Section of Molecular Diabetes and Metabolism, Institute of Molecular Medicine and Institute of Clinical Research, University of Southern Denmark, Odense, Denmark
| | - Jørgen F P Wojtaszewski
- Section of Molecular Physiology, Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, Copenhagen, DK2100, Denmark
| | - Xiaoyong Yang
- Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Matthew W Hulver
- Department of Human Nutrition, Foods, and Exercise, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA; The Virginia Tech Metabolic Phenotyping Core, Blacksburg, VA 24061, USA
| | - Richard F Helm
- Department of Biochemistry, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA
| | - Jonas T Treebak
- Section of Integrative Physiology, Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, DK2200, Denmark.
| | - David E Gerrard
- Department of Animal and Poultry Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA.
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Güth R, Pinch M, Samanta MP, Chaidez A, Unguez GA. Sternopygus macrurus electric organ transcriptome and cell size exhibit insensitivity to short-term electrical inactivity. ACTA ACUST UNITED AC 2016; 110:233-44. [PMID: 27864094 DOI: 10.1016/j.jphysparis.2016.11.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Revised: 09/03/2016] [Accepted: 11/13/2016] [Indexed: 11/22/2022]
Abstract
Electrical activity is an important regulator of cellular function and gene expression in electrically excitable cell types. In the weakly electric teleost fish Sternopygus macrurus, electrocytes, i.e., the current-producing cells of the electric organ, derive from a striated muscle lineage. Mature electrocytes are larger than muscle fibers, do not contain sarcomeres, and are driven continuously at frequencies higher than those exerted on muscle cells. Previous work showed that the removal of electrical activity by spinal cord transection (ST) for two and five weeks led to an upregulation of some sarcomeric proteins and a decrease in electrocyte size. To test whether changes in gene transcription preceded these phenotypic changes, we determined the sensitivity of electrocyte gene expression to electrical inactivity periods of two and five days after ST. Whole tissue gene expression profiles using deep RNA sequencing showed minimal alterations in the levels of myogenic transcription factor and sarcomeric transcripts after either ST period. Moreover, while analysis of differentially expressed genes showed a transient upregulation of genes associated with proteolytic mechanisms at two days and an increase in mRNA levels of cytoskeletal genes at five days after electrical silencing, electrocyte size was not affected. Electrical inactivity also resulted in the downregulation of genes that were classified into enriched clusters associated with functions of axon migration and synapse structure. Overall, these data demonstrate that unlike tissues in the myogenic lineage in other vertebrate species, regulation of gene transcription and cell size in the muscle-like electrocytes of S. macrurus is highly insensitive to short-term electrical inactivity. Moreover, together with data obtained from control and long-term ST studies, the present data suggest that neural input might influence post-transcriptional processes to affect the mature electrocyte phenotype.
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Wang W, Wang J, Lu HY, Ma WS, Dong FS, Hu XY, Liu CY. The effects of increasing occlusal vertical dimension on the deep masseter of rat at different ages. Arch Oral Biol 2016; 74:12-20. [PMID: 27842253 DOI: 10.1016/j.archoralbio.2016.10.031] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2015] [Revised: 10/01/2016] [Accepted: 10/27/2016] [Indexed: 11/27/2022]
Abstract
OBJECTIVE To investigate the influence of increasing the occlusal vertical dimension (iOVD) on the fibre-type distribution and ultrastructure of deep masseter of rat at different ages. DESIGN A total of forty-eight male Wistar rats were divided into two groups according to age: 'teenage' group (n=24, 1.5 months) and 'young adult' group (n=24, 8 months). Both the teenage and the young adult rats were then randomly divided into the control group (n=12) and the experimental group (n=12). The occlusal vertical dimensions of the rats in the experimental groups were increased by placing composite resin on all maxillary molars. The fibre-type distribution and ultrastructure of the deep masseter were subsequently observed on day 7 and day 14 after iOVD. RESULTS In the teenage experimental group, the proportion of type IIa fibres increased, while the proportion of type IIb and type IIx fibres decreased by day 7 after iOVD (P<0.05). However, no significant fibre phenotype transformation was observed in the young adult experimental group until day 14 after iOVD. In addition, the proportion of type IIa in the teenage experimental group was higher than that of the young adult experimental group on day 7 and 14 (P<0.05). Under the transmission electron microscope, muscle fibre reconstruction and the compensatory increase in the number and volume of mitochondria appeared earlier in the teenage experimental group. The cellular traumatic reaction was less than that in the young adult experimental group. CONCLUSION The teenage rat alters masseter muscle structure to a slower phenotype earlier and to a greater degree than that of the young adult rat when increasing the occlusal vertical dimension.
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Affiliation(s)
- Wen Wang
- Department of Orthodontics, College of Stomatology, Hebei Medical University, Shijiazhuang 050017, PR China.
| | - Jie Wang
- Department of Oral Pathology, College of Stomatology, Hebei Medical University, Shijiazhuang 050017, PR China.
| | - Hai-Yan Lu
- Department of Orthodontics, College of Stomatology, Hebei Medical University, Shijiazhuang 050017, PR China.
| | - Wen-Sheng Ma
- Department of Orthodontics, College of Stomatology, Hebei Medical University, Shijiazhuang 050017, PR China.
| | - Fu-Sheng Dong
- Department of Oral & Maxillofacial Surgery, College of Stomatology, Hebei Medical University, Shijiazhuang 050017, PR China.
| | - Xiao-Ying Hu
- Department of Orthodontics, College of Stomatology, Hebei Medical University, Shijiazhuang 050017, PR China.
| | - Chun-Yan Liu
- Department of Orthodontics, College of Stomatology, Hebei Medical University, Shijiazhuang 050017, PR China.
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Botzenhart UU, Wegenstein C, Todorov T, Kunert-Keil C. Influence of Botulinumtoxin A on the Expression of Adult MyHC Isoforms in the Masticatory Muscles in Dystrophin-Deficient Mice (Mdx-Mice). Biomed Res Int 2016; 2016:7063093. [PMID: 27689088 DOI: 10.1155/2016/7063093] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/29/2016] [Revised: 06/27/2016] [Accepted: 07/10/2016] [Indexed: 11/17/2022]
Abstract
The most widespread animal model to investigate Duchenne muscular dystrophy is the mdx-mouse. In contrast to humans, phases of muscle degeneration are replaced by regeneration processes; hence there is only a restricted time slot for research. The aim of the study was to investigate if an intramuscular injection of BTX-A is able to break down muscle regeneration and has direct implications on the gene expression of myosin heavy chains in the corresponding treated and untreated muscles. Therefore, paralysis of the right masseter muscle was induced in adult healthy and dystrophic mice by a specific intramuscular injection of BTX-A. After 21 days the mRNA expression and protein content of MyHC isoforms of the right and left masseter, temporal, and the tongue muscle were determined using quantitative RT-PCR and Western blot technique. MyHC-IIa and MyHC-I-mRNA expression significantly increased in the paralyzed masseter muscle of control-mice, whereas MyHC-IIb and MyHC-IIx/d-mRNA were decreased. In dystrophic muscles no effect of BTX-A could be detected at the level of MyHC. This study suggests that BTX-A injection is a suitable method to simulate DMD-pathogenesis in healthy mice but further investigations are necessary to fully analyse the BTX-A effect and to generate sustained muscular atrophy in mdx-mice.
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9
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Pinch M, Güth R, Samanta MP, Chaidez A, Unguez GA. The myogenic electric organ of Sternopygus macrurus: a non-contractile tissue with a skeletal muscle transcriptome. PeerJ 2016; 4:e1828. [PMID: 27114860 PMCID: PMC4841239 DOI: 10.7717/peerj.1828] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2015] [Accepted: 02/29/2016] [Indexed: 12/13/2022] Open
Abstract
In most electric fish species, the electric organ (EO) derives from striated muscle cells that suppress many muscle properties. In the gymnotiform Sternopygus macrurus, mature electrocytes, the current-producing cells of the EO, do not contain sarcomeres, yet they continue to make some cytoskeletal and sarcomeric proteins and the muscle transcription factors (MTFs) that induce their expression. In order to more comprehensively examine the transcriptional regulation of genes associated with the formation and maintenance of the contractile sarcomere complex, results from expression analysis using qRT-PCR were informed by deep RNA sequencing of transcriptomes and miRNA compositions of muscle and EO tissues from adult S. macrurus. Our data show that: (1) components associated with the homeostasis of the sarcomere and sarcomere-sarcolemma linkage were transcribed in EO at levels similar to those in muscle; (2) MTF families associated with activation of the skeletal muscle program were not differentially expressed between these tissues; and (3) a set of microRNAs that are implicated in regulation of the muscle phenotype are enriched in EO. These data support the development of a unique and highly specialized non-contractile electrogenic cell that emerges from a striated phenotype and further differentiates with little modification in its transcript composition. This comprehensive analysis of parallel mRNA and miRNA profiles is not only a foundation for functional studies aimed at identifying mechanisms underlying the transcription-independent myogenic program in S. macrurus EO, but also has important implications to many vertebrate cell types that independently activate or suppress specific features of the skeletal muscle program.
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Affiliation(s)
- Matthew Pinch
- Department of Biology, New Mexico State University, Las Cruces, NM, United States
| | - Robert Güth
- Department of Biology, New Mexico State University, Las Cruces, NM, United States
| | | | - Alexander Chaidez
- Department of Biology, New Mexico State University, Las Cruces, NM, United States
| | - Graciela A. Unguez
- Department of Biology, New Mexico State University, Las Cruces, NM, United States
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Stark DA, Coffey NJ, Pancoast HR, Arnold LL, Walker JPD, Vallée J, Robitaille R, Garcia ML, Cornelison DDW. Ephrin-A3 promotes and maintains slow muscle fiber identity during postnatal development and reinnervation. J Cell Biol 2016; 211:1077-91. [PMID: 26644518 PMCID: PMC4674275 DOI: 10.1083/jcb.201502036] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
During neuromuscular junction maturation and repair, ephrin-A3 is expressed by all slow (Type I) fibers and only by slow fibers, and inhibits their innervation by fast motor axons via repulsive interactions with the ephrin-A3 receptor EphA8. Each adult mammalian skeletal muscle has a unique complement of fast and slow myofibers, reflecting patterns established during development and reinforced via their innervation by fast and slow motor neurons. Existing data support a model of postnatal "matching" whereby predetermined myofiber type identity promotes pruning of inappropriate motor axons, but no molecular mechanism has yet been identified. We present evidence that fiber type–specific repulsive interactions inhibit innervation of slow myofibers by fast motor axons during both postnatal maturation of the neuromuscular junction and myofiber reinnervation after injury. The repulsive guidance ligand ephrin-A3 is expressed only on slow myofibers, whereas its candidate receptor, EphA8, localizes exclusively to fast motor endplates. Adult mice lacking ephrin-A3 have dramatically fewer slow myofibers in fast and mixed muscles, and misexpression of ephrin-A3 on fast myofibers followed by denervation/reinnervation promotes their respecification to a slow phenotype. We therefore conclude that Eph/ephrin interactions guide the fiber type specificity of neuromuscular interactions during development and adult life.
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Affiliation(s)
- Danny A Stark
- Division of Biological Sciences, University of Missouri, Columbia, MO 65211 Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, MO 65211
| | - Nathan J Coffey
- Division of Biological Sciences, University of Missouri, Columbia, MO 65211
| | - Hannah R Pancoast
- Division of Biological Sciences, University of Missouri, Columbia, MO 65211
| | - Laura L Arnold
- Division of Biological Sciences, University of Missouri, Columbia, MO 65211 Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, MO 65211
| | - J Peyton D Walker
- Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, MO 65211
| | - Joanne Vallée
- Département de Neurosciences, Université de Montréal, Montréal, Québec H3C 3J7, Canada
| | - Richard Robitaille
- Département de Neurosciences, Université de Montréal, Montréal, Québec H3C 3J7, Canada Groupe de Recherche sur le Système Nerveux Central, Université de Montréal, Montréal, Québec H3C 3J7, Canada
| | - Michael L Garcia
- Division of Biological Sciences, University of Missouri, Columbia, MO 65211 Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, MO 65211
| | - D D W Cornelison
- Division of Biological Sciences, University of Missouri, Columbia, MO 65211 Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, MO 65211
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Soukup T, Smerdu V. Effect of altered innervation and thyroid hormones on myosin heavy chain expression and fiber type transitions: a mini-review. Histochem Cell Biol 2015; 143:123-30. [DOI: 10.1007/s00418-014-1276-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/01/2014] [Indexed: 01/19/2023]
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12
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Kopecká K, Zacharova G, Smerdu V, Soukup T. Slow to fast muscle transformation following heterochronous isotransplantation is influenced by host thyroid hormone status. Histochem Cell Biol 2014; 142:677-84. [DOI: 10.1007/s00418-014-1247-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/27/2014] [Indexed: 11/26/2022]
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13
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Guerrero L, Villar P, Martínez L, Badia-Careaga C, Arredondo JJ, Cervera M. In vivo cell tracking of mouse embryonic myoblasts and fast fibers during development. Genesis 2014; 52:793-808. [PMID: 24895317 DOI: 10.1002/dvg.22796] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2013] [Revised: 05/30/2014] [Accepted: 05/31/2014] [Indexed: 11/05/2022]
Abstract
Fast and slow TnI are co-expressed in E11.5 embryos, and fast TnI is present from the very beginning of myogenesis. A novel green fluorescent protein (GFP) reporter mouse lines (FastTnI/GFP lines) that carry the primary and secondary enhancer elements of the mouse fast troponin I (fast TnI), in which reporter expression correlates precisely with distribution of the endogenous fTnI protein was generated. Using the FastTnI/GFP mouse model, we characterized the early myogenic events in mice, analyzing the migration of GFP+ myoblasts, and the formation of primary and secondary myotubes in transgenic embryos. Interestingly, we found that the two contractile fast and slow isoforms of TnI are expressed during the migration of myoblasts from the somites to the limbs and body wall, suggesting that both participate in these events. Since no sarcomeres are present in myoblasts, we speculate that the function of fast TnI in early myogenesis is, like Myosin and Tropomyosin, to participate in cell movement during the initial myogenic stages. genesis
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Affiliation(s)
- Lucia Guerrero
- Departamento de Bioquímica, Facultad de Medicina, Universidad Autónoma de Madrid, Instituto de Investigaciones Biomédicas Alberto Sols, C.S.I.C., Madrid, Spain
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Abstract
Skeletal myogenesis has been and is currently under extensive study in both mammals and teleosts, with the latter providing a good model for skeletal myogenesis because of their flexible and conserved genome. Parallel investigations of muscle studies using both these models have strongly accelerated the advances in the field. However, when transferring the knowledge from one model to the other, it is important to take into account both their similarities and differences. The main difficulties in comparing mammals and teleosts arise from their different temporal development. Conserved aspects can be seen for muscle developmental origin and segmentation, and for the presence of multiple myogenic waves. Among the divergences, many fish have an indeterminate growth capacity throughout their entire life span, which is absent in mammals, thus implying different post-natal growth mechanisms. This review covers the current state of the art on myogenesis, with a focus on the most conserved and divergent aspects between mammals and teleosts.
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Affiliation(s)
- Giuliana Rossi
- Department of Biosciences, University of Milan, 20133, Milan, Italy
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15
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Jorquera G, Altamirano F, Contreras-Ferrat A, Almarza G, Buvinic S, Jacquemond V, Jaimovich E, Casas M. Cav1.1 controls frequency-dependent events regulating adult skeletal muscle plasticity. J Cell Sci 2013; 126:1189-98. [PMID: 23321639 DOI: 10.1242/jcs.116855] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
An important pending question in neuromuscular biology is how skeletal muscle cells decipher the stimulation pattern coming from motoneurons to define their phenotype as slow or fast twitch muscle fibers. We have previously shown that voltage-gated L-type calcium channel (Cav1.1) acts as a voltage sensor for activation of inositol (1,4,5)-trisphosphate [Ins(1,4,5)P₃]-dependent Ca(2+) signals that regulates gene expression. ATP released by muscle cells after electrical stimulation through pannexin-1 channels plays a key role in this process. We show now that stimulation frequency determines both ATP release and Ins(1,4,5)P₃ production in adult skeletal muscle and that Cav1.1 and pannexin-1 colocalize in the transverse tubules. Both ATP release and increased Ins(1,4,5)P₃ was seen in flexor digitorum brevis fibers stimulated with 270 pulses at 20 Hz, but not at 90 Hz. 20 Hz stimulation induced transcriptional changes related to fast-to-slow muscle fiber phenotype transition that required ATP release. Addition of 30 µM ATP to fibers induced the same transcriptional changes observed after 20 Hz stimulation. Myotubes lacking the Cav1.1-α1 subunit released almost no ATP after electrical stimulation, showing that Cav1.1 has a central role in this process. In adult muscle fibers, ATP release and the transcriptional changes produced by 20 Hz stimulation were blocked by both the Cav1.1 antagonist nifedipine (25 µM) and by the Cav1.1 agonist (-)S-BayK 8644 (10 µM). We propose a new role for Cav1.1, independent of its calcium channel activity, in the activation of signaling pathways allowing muscle fibers to decipher the frequency of electrical stimulation and to activate specific transcriptional programs that define their phenotype.
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Affiliation(s)
- Gonzalo Jorquera
- Centro de Estudios Moleculares de Célula, ICBM, Facultad de Medicina, Universidad de Chile, Independencia 1027-8380453, Santiago, Chile
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Hu JKH, McGlinn E, Harfe BD, Kardon G, Tabin CJ. Autonomous and nonautonomous roles of Hedgehog signaling in regulating limb muscle formation. Genes Dev 2012; 26:2088-102. [PMID: 22987639 DOI: 10.1101/gad.187385.112] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Muscle progenitor cells migrate from the lateral somites into the developing vertebrate limb, where they undergo patterning and differentiation in response to local signals. Sonic hedgehog (Shh) is a secreted molecule made in the posterior limb bud that affects patterning and development of multiple tissues, including skeletal muscles. However, the cell-autonomous and non-cell-autonomous functions of Shh during limb muscle formation have remained unclear. We found that Shh affects the pattern of limb musculature non-cell-autonomously, acting through adjacent nonmuscle mesenchyme. However, Shh plays a cell-autonomous role in maintaining cell survival in the dermomyotome and initiating early activation of the myogenic program in the ventral limb. At later stages, Shh promotes slow muscle differentiation cell-autonomously. In addition, Shh signaling is required cell-autonomously to regulate directional muscle cell migration in the distal limb. We identify neuroepithelial cell transforming gene 1 (Net1) as a downstream target and effector of Shh signaling in that context.
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Affiliation(s)
- Jimmy Kuang-Hsien Hu
- Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115, USA
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Murakami S, Fujita N, Kondo H, Takeda I, Momota R, Ohtsuka A, Fujino H. Abnormalities in the fiber composition and capillary architecture in the soleus muscle of type 2 diabetic Goto-Kakizaki rats. ScientificWorldJournal 2012; 2012:680189. [PMID: 23213294 PMCID: PMC3504414 DOI: 10.1100/2012/680189] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2012] [Accepted: 10/16/2012] [Indexed: 11/30/2022] Open
Abstract
Type 2 diabetes mellitus is linked to impaired skeletal muscle glucose uptake and storage. This study aimed to investigate the fiber type distributions and the three-dimensional (3D) architecture of the capillary network in the skeletal muscles of type 2 diabetic rats. Muscle fiber type transformation, succinate dehydrogenase (SDH) activity, capillary density, and 3D architecture of the capillary network in the soleus muscle were determined in 36-week-old Goto-Kakizaki (GK) rats as an animal model of nonobese type 2 diabetes and age-matched Wistar (Cont) rats. Although the soleus muscle of Cont rats comprised both type I and type IIA fibers, the soleus muscle of GK rats had only type I fibers. In addition, total SDH activity in the soleus muscle of GK rats was significantly lower than that in Cont rats because GK rats had no high-SDH activity type IIA fiber in the soleus muscle. Furthermore, the capillary diameter, capillary tortuosity, and microvessel volume in GK rats were significantly lower than those in Cont rats. These results indicate that non-obese diabetic GK rats have muscle fiber type transformation, low SDH activity, and reduced skeletal muscle capillary content, which may be related to the impaired glucose metabolism characteristic of type 2 diabetes.
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Affiliation(s)
- Shinichiro Murakami
- Department of Physical Therapy, Himeji Dokkyo University, Himeji, Hyogo 670-8524, Japan.
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18
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Abdelhadi O, Babiker S, Picard B, Jurie C, Jailler R, Hocquette J, Faye B. Effect of season on contractile and metabolic properties of desert camel muscle (Camelus dromedarius). Meat Sci 2012; 90:139-44. [DOI: 10.1016/j.meatsci.2011.06.012] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2010] [Revised: 05/25/2011] [Accepted: 06/10/2011] [Indexed: 10/18/2022]
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Richard AF, Demignon J, Sakakibara I, Pujol J, Favier M, Strochlic L, Le Grand F, Sgarioto N, Guernec A, Schmitt A, Cagnard N, Huang R, Legay C, Guillet-Deniau I, Maire P. Genesis of muscle fiber-type diversity during mouse embryogenesis relies on Six1 and Six4 gene expression. Dev Biol 2011; 359:303-20. [DOI: 10.1016/j.ydbio.2011.08.010] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2011] [Revised: 07/22/2011] [Accepted: 08/15/2011] [Indexed: 01/28/2023]
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20
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An CI, Dong Y, Hagiwara N. Genome-wide mapping of Sox6 binding sites in skeletal muscle reveals both direct and indirect regulation of muscle terminal differentiation by Sox6. BMC Dev Biol 2011; 11:59. [PMID: 21985497 PMCID: PMC3239296 DOI: 10.1186/1471-213x-11-59] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/16/2011] [Accepted: 10/10/2011] [Indexed: 01/06/2023]
Abstract
Background Sox6 is a multi-faceted transcription factor involved in the terminal differentiation of many different cell types in vertebrates. It has been suggested that in mice as well as in zebrafish Sox6 plays a role in the terminal differentiation of skeletal muscle by suppressing transcription of slow fiber specific genes. In order to understand how Sox6 coordinately regulates the transcription of multiple fiber type specific genes during muscle development, we have performed ChIP-seq analyses to identify Sox6 target genes in mouse fetal myotubes and generated muscle-specific Sox6 knockout (KO) mice to determine the Sox6 null muscle phenotype in adult mice. Results We have identified 1,066 Sox6 binding sites using mouse fetal myotubes. The Sox6 binding sites were found to be associated with slow fiber-specific, cardiac, and embryonic isoform genes that are expressed in the sarcomere as well as transcription factor genes known to play roles in muscle development. The concurrently performed RNA polymerase II (Pol II) ChIP-seq analysis revealed that 84% of the Sox6 peak-associated genes exhibited little to no binding of Pol II, suggesting that the majority of the Sox6 target genes are transcriptionally inactive. These results indicate that Sox6 directly regulates terminal differentiation of muscle by affecting the expression of sarcomere protein genes as well as indirectly through influencing the expression of transcription factors relevant to muscle development. Gene expression profiling of Sox6 KO skeletal and cardiac muscle revealed a significant increase in the expression of the genes associated with Sox6 binding. In the absence of the Sox6 gene, there was dramatic upregulation of slow fiber-specific, cardiac, and embryonic isoform gene expression in Sox6 KO skeletal muscle and fetal isoform gene expression in Sox6 KO cardiac muscle, thus confirming the role Sox6 plays as a transcriptional suppressor in muscle development. Conclusions Our present data indicate that during development, Sox6 functions as a transcriptional suppressor of fiber type-specific and developmental isoform genes to promote functional specification of muscle which is critical for optimum muscle performance and health.
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Affiliation(s)
- Chung-Il An
- Division of Cardiovascular Medicine, Department of Internal Medicine, University of California, Davis, One Shields Avenue, Davis, California 95616, USA
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21
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Wang J, Li X, Yang X, Sun Q, Huang R, Xing J, Zhao R. Maternal dietary protein induces opposite myofiber type transition in Meishan pigs at weaning and finishing stages. Meat Sci 2011; 89:221-7. [DOI: 10.1016/j.meatsci.2011.04.023] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2010] [Revised: 01/21/2011] [Accepted: 04/20/2011] [Indexed: 01/21/2023]
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Mathew SJ, Hansen JM, Merrell AJ, Murphy MM, Lawson JA, Hutcheson DA, Hansen MS, Angus-Hill M, Kardon G. Connective tissue fibroblasts and Tcf4 regulate myogenesis. Development 2011; 138:371-84. [PMID: 21177349 DOI: 10.1242/dev.057463] [Citation(s) in RCA: 231] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Muscle and its connective tissue are intimately linked in the embryo and in the adult, suggesting that interactions between these tissues are crucial for their development. However, the study of muscle connective tissue has been hindered by the lack of molecular markers and genetic reagents to label connective tissue fibroblasts. Here, we show that the transcription factor Tcf4 (transcription factor 7-like 2; Tcf7l2) is strongly expressed in connective tissue fibroblasts and that Tcf4(GFPCre) mice allow genetic manipulation of these fibroblasts. Using this new reagent, we find that connective tissue fibroblasts critically regulate two aspects of myogenesis: muscle fiber type development and maturation. Fibroblasts promote (via Tcf4-dependent signals) slow myogenesis by stimulating the expression of slow myosin heavy chain. Also, fibroblasts promote the switch from fetal to adult muscle by repressing (via Tcf4-dependent signals) the expression of developmental embryonic myosin and promoting (via a Tcf4-independent mechanism) the formation of large multinucleate myofibers. In addition, our analysis of Tcf4 function unexpectedly reveals a novel mechanism of intrinsic regulation of muscle fiber type development. Unlike other intrinsic regulators of fiber type, low levels of Tcf4 in myogenic cells promote both slow and fast myogenesis, thereby promoting overall maturation of muscle fiber type. Thus, we have identified novel extrinsic and intrinsic mechanisms regulating myogenesis. Most significantly, our data demonstrate for the first time that connective tissue is important not only for adult muscle structure and function, but is a vital component of the niche within which muscle progenitors reside and is a critical regulator of myogenesis.
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Affiliation(s)
- Sam J Mathew
- Department of Human Genetics, University of Utah, 15 North 2030 East, Salt Lake City, Utah 84112, USA
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Abstract
Skeletal muscle fiber generation occurs principally in two myogenic phases: (1) Primary (embryonic) myogenesis when myoblasts proliferate and fuse to form primary myotubes and (2) secondary (fetal) myogenesis when successive waves of myoblasts fuse along the surface of the primary myotubes, giving rise to a population of smaller and more numerous secondary myotubes. This sequence of events determines fiber number and is completed at or soon after birth in most muscles of the mouse. The adult myostatin null mouse (MSTN(-/-)) displays both an increase in fiber number and size relative to wild type (MSTN(+/+)), suggesting a developmental origin for the hypermuscular phenotype. The focus of the present study was to determine at which point during myogenesis do MSTN(-/-) animals diverge from MSTN(+/+). To achieve this, we focused on the extensor digitorum longus (EDL) muscle and evaluated primary myotube number at embryonic day (E) 13.0 and E14.5 and secondary to primary myotube ratios at E18.5. We show that primary myotube number and size were significantly increased in the MSTN(-/-) mice by E14.5 and the secondary to primary myotube ratio increased at E18.5. This increase in the rate of fiber formation resulted in MSTN(-/-) mice harboring 87% of their final adult fiber number at E18.5, compared to only 73% in MSTN(+/+). An accelerated myogenic program in the MSTN(-/-) mice was further confirmed by our finding of an initial expansion in the myogenic stem cell (identified through Pax7 expression) and myoblast (identified through myogenin expression) cell pools at E14.5 in the EDL muscle of these animals that was, however, followed by a reduction of both populations of cells at E18.5 relative to MSTN(+/+). Overall these data suggest that the genetic loss of myostatin accelerates the developmental myogenic program of primary and secondary skeletal myogenesis.
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Affiliation(s)
- Antonios Matsakas
- School of Biological Sciences, University of Reading, Reading, United Kingdom
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25
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Abstract
Muscle development, growth, and regeneration take place throughout vertebrate life. In amniotes, myogenesis takes place in four successive, temporally distinct, although overlapping phases. Understanding how embryonic, fetal, neonatal, and adult muscle are formed from muscle progenitors and committed myoblasts is an area of active research. In this review we examine recent expression, genetic loss-of-function, and genetic lineage studies that have been conducted in the mouse, with a particular focus on limb myogenesis. We synthesize these studies to present a current model of how embryonic, fetal, neonatal, and adult muscle are formed in the limb.
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Affiliation(s)
- Malea Murphy
- Department of Human Genetics, University of Utah, Salt Lake City, Utah, USA
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Casas M, Figueroa R, Jorquera G, Escobar M, Molgó J, Jaimovich E. IP(3)-dependent, post-tetanic calcium transients induced by electrostimulation of adult skeletal muscle fibers. ACTA ACUST UNITED AC 2010; 136:455-67. [PMID: 20837675 PMCID: PMC2947059 DOI: 10.1085/jgp.200910397] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Tetanic electrical stimulation induces two separate calcium signals in rat skeletal myotubes, a fast one, dependent on Cav 1.1 or dihydropyridine receptors (DHPRs) and ryanodine receptors and related to contraction, and a slow signal, dependent on DHPR and inositol trisphosphate receptors (IP3Rs) and related to transcriptional events. We searched for slow calcium signals in adult muscle fibers using isolated adult flexor digitorum brevis fibers from 5–7-wk-old mice, loaded with fluo-3. When stimulated with trains of 0.3-ms pulses at various frequencies, cells responded with a fast calcium signal associated with muscle contraction, followed by a slower signal similar to one previously described in cultured myotubes. Nifedipine inhibited the slow signal more effectively than the fast one, suggesting a role for DHPR in its onset. The IP3R inhibitors Xestospongin B or C (5 µM) also inhibited it. The amplitude of post-tetanic calcium transients depends on both tetanus frequency and duration, having a maximum at 10–20 Hz. At this stimulation frequency, an increase of the slow isoform of troponin I mRNA was detected, while the fast isoform of this gene was inhibited. All three IP3R isoforms were present in adult muscle. IP3R-1 was differentially expressed in different types of muscle fibers, being higher in a subset of fast-type fibers. Interestingly, isolated fibers from the slow soleus muscle did not reveal the slow calcium signal induced by electrical stimulus. These results support the idea that IP3R-dependent slow calcium signals may be characteristic of distinct types of muscle fibers and may participate in the activation of specific transcriptional programs of slow and fast phenotype.
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Affiliation(s)
- Mariana Casas
- Centro de Estudios Moleculares de la Célula, ICBM, Facultad de Medicina, Universidad de Chile, Santiago, Chile
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Abstract
UNLABELLED Voice and swallowing dysfunction as a result of recurrent laryngeal nerve paralysis can be improved with vocal fold injections or laryngeal framework surgery. However, denervation atrophy can cause late-term clinical failure. A major determinant of skeletal muscle physiology is myosin heavy chain (MyHC) expression, and previous protein analyses have shown changes in laryngeal muscle fiber MyHC isoform with denervation. RNA analyses in this setting have not been performed, and understanding RNA levels will allow interventions better designed to reverse processes such as denervation in the future. Total RNA was extracted from bilateral rat thyroarytenoid (TA), posterior cricoarytenoid (PCA), and cricothyroid (CT) muscles in rats. Primers were designed using published MyHC isoform sequences. SYBR Green real-time reverse transcription-polymerase chain reaction (SYBR-RT-PCR) was used for quantification. The electropherogram showed a clear separation of total RNA to 28S and 18S subunits. Melting curves illustrated single peaks for all type MyHC primers. All MyHC isoforms were identified in all muscles with various degrees of expression. Quantitative PCR is a sensitive method to detect MyHC isoforms in laryngeal muscle. Isoform expression using mRNA analysis was similar to previous analyses but showed some important differences. This technique can be used to quantitatively assess response to interventions targeted to maintain muscle bulk after denervation. LEARNING OUTCOMES (1) Readers will be able to describe the relationship between myosin heavy chain expression and muscle contractile properties. (2) Readers will be able to separate myosin heavy chain isoforms into slow and fast twitch phenotypes. (3) Readers will be able to describe differential muscle isoform expression between different laryngeal muscles. (4) Readers will be able to compare this study to other modalities of determining muscle fiber type.
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Affiliation(s)
- Douglas J Van Daele
- Department of Otolaryngology - Head and Neck Surgery, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA, USA.
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28
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Abstract
During development, skeletal muscles adapt to stage-specific functional and metabolic challenges by switching the expression of specific subset of genes. The mechanism that governs these changes is still enigmatic. In a recent issue of Cell, Messina and coworkers shed light on this issue through the identification of a transcription factor--NFix--that coordinates the switch in gene expression at the transition from embryonic to fetal myoblasts.
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Messina G, Biressi S, Monteverde S, Magli A, Cassano M, Perani L, Roncaglia E, Tagliafico E, Starnes L, Campbell CE, Grossi M, Goldhamer DJ, Gronostajski RM, Cossu G. Nfix regulates fetal-specific transcription in developing skeletal muscle. Cell 2010; 140:554-66. [PMID: 20178747 DOI: 10.1016/j.cell.2010.01.027] [Citation(s) in RCA: 147] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2009] [Revised: 11/04/2009] [Accepted: 01/14/2010] [Indexed: 12/29/2022]
Abstract
Skeletal myogenesis, like hematopoiesis, occurs in successive developmental stages that involve different cell populations and expression of different genes. We show here that the transcription factor nuclear factor one X (Nfix), whose expression is activated by Pax7 in fetal muscle, in turn activates the transcription of fetal specific genes such as MCK and beta-enolase while repressing embryonic genes such as slow myosin. In the case of the MCK promoter, Nfix forms a complex with PKC theta that binds, phosphorylates, and activates MEF2A. Premature expression of Nfix activates fetal and suppresses embryonic genes in embryonic muscle, whereas muscle-specific ablation of Nfix prevents fetal and maintains embryonic gene expression in the fetus. Therefore, Nfix acts as a transcriptional switch from embryonic to fetal myogenesis.
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Niro C, Demignon J, Vincent S, Liu Y, Giordani J, Sgarioto N, Favier M, Guillet-Deniau I, Blais A, Maire P. Six1 and Six4 gene expression is necessary to activate the fast-type muscle gene program in the mouse primary myotome. Dev Biol 2010; 338:168-82. [DOI: 10.1016/j.ydbio.2009.11.031] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2009] [Revised: 11/24/2009] [Accepted: 11/25/2009] [Indexed: 01/18/2023]
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31
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Lefaucheur L. A second look into fibre typing – Relation to meat quality. Meat Sci 2010; 84:257-70. [DOI: 10.1016/j.meatsci.2009.05.004] [Citation(s) in RCA: 206] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2009] [Revised: 04/16/2009] [Accepted: 05/03/2009] [Indexed: 12/25/2022]
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Hutcheson DA, Zhao J, Merrell A, Haldar M, Kardon G. Embryonic and fetal limb myogenic cells are derived from developmentally distinct progenitors and have different requirements for beta-catenin. Genes Dev 2009; 23:997-1013. [PMID: 19346403 DOI: 10.1101/gad.1769009] [Citation(s) in RCA: 204] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Vertebrate muscle arises sequentially from embryonic, fetal, and adult myoblasts. Although functionally distinct, it is unclear whether these myoblast classes develop from common or different progenitors. Pax3 and Pax7 are expressed by somitic myogenic progenitors and are critical myogenic determinants. To test the developmental origin of embryonic and fetal myogenic cells in the limb, we genetically labeled and ablated Pax3(+) and Pax7(+) cells. Pax3(+)Pax7(-) cells contribute to muscle and endothelium, establish and are required for embryonic myogenesis, and give rise to Pax7(+) cells. Subsequently, Pax7(+) cells give rise to and are required for fetal myogenesis. Thus, Pax3(+) and Pax7(+) cells contribute differentially to embryonic and fetal limb myogenesis. To investigate whether embryonic and fetal limb myogenic cells have different genetic requirements we conditionally inactivated or activated beta-catenin, an important regulator of myogenesis, in Pax3- or Pax7-derived cells. beta-Catenin is necessary within the somite for dermomyotome and myotome formation and delamination of limb myogenic progenitors. In the limb, beta-catenin is not required for embryonic myoblast specification or myofiber differentiation but is critical for determining fetal progenitor number and myofiber number and type. Together, these studies demonstrate that limb embryonic and fetal myogenic cells develop from distinct, but related progenitors and have different cell-autonomous requirements for beta-catenin.
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Affiliation(s)
- David A Hutcheson
- Department of Human Genetics, University of Utah, Salt Lake City, Utah 84112, USA
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Stevens L, Bastide B, Maurage CA, Dupont E, Montel V, Cieniewski-Bernard C, Cuisset JM, Vallée L, Mounier Y. Childhood spinal muscular atrophy induces alterations in contractile and regulatory protein isoform expressions. Neuropathol Appl Neurobiol 2008; 34:659-70. [DOI: 10.1111/j.1365-2990.2008.00950.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Abstract
Skeletal muscles are composed of several types of fibers with different contractile and metabolic properties. Genetic background and type of innervation of the fibers primarily determine these properties, but thyroid hormone (TH) is a powerful modulator of the fiber phenotype. The rates of contraction and relaxation are stimulated by TH, as are the energy consumption and heat production associated with activity. Quantitative and qualitative changes in substrate metabolism accommodate the increase in ATP turnover. Because of the total mass of skeletal muscle, these changes affect whole-body physiology. Although apparently straightforward, the phenotypic shifts induced by TH are highly complex and fiber specific. This review addresses the mechanisms by which TH may modulate fiber gene expression and discusses some of the implications of the TH-regulated changes in metabolic and contractile phenotype of skeletal muscle.
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Affiliation(s)
- Warner S Simonides
- Laboratory for Physiology, Institute for Cardiovascular Research VU University Medical Center, Amsterdam, The Netherlands.
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Abstract
Sox6, a member of the Sox family of transcription factors, is highly expressed in skeletal muscle. Despite its abundant expression, the role of Sox6 in muscle development is not well understood. We hypothesize that, in fetal muscle, Sox6 functions as a repressor of slow fiber type-specific genes. In the wild-type mouse, differentiation of fast and slow fibers becomes apparent during late fetal stages (after approximately embryonic day 16). However, in the Sox6 null-p(100H) mutant mouse, all fetal muscle fibers maintain slow fiber characteristics, as evidenced by expression of the slow myosin heavy chain MyHC-beta. Knockdown of Sox6 expression in wild-type myotubes results in a significant increase in MyHC-beta expression, supporting our hypothesis. Analysis of the MyHC-beta promoter revealed a Sox consensus sequence that likely functions as a negative cis-regulatory element. Together, our results suggest that Sox6 plays a critical role in the fiber type differentiation of fetal skeletal muscle.
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Affiliation(s)
- Nobuko Hagiwara
- University of California, Davis, Division of Cardiovascular Medicine/Rowe Program in Human Genetics, Davis, California 95616, USA.
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Li Y, Yuan L, Yang X, Ni Y, Xia D, Barth S, Grossmann R, Zhao RQ. Effect of early feed restriction on myofibre types and expression of growth-related genes in the gastrocnemius muscle of crossbred broiler chickens. Br J Nutr 2007; 98:310-9. [PMID: 17445349 DOI: 10.1017/s0007114507699383] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The purpose of this study was to investigate the immediate and long-term effects of early feed restriction (ER) on morphology and gene expression of lateral gastrocnemius muscle. Newly hatched crossbred broiler chickens were allocated into control and ER groups, the latter being free-fed on alternate days from hatch to 14 days of age (14 d), followed by ad libitum feeding as the control group until 63 d. The lateral gastrocnemius muscle was taken at 14 and 63 d, respectively for myofibre typing by both myosin ATPase staining and relative quantification of myosin heavy chain (MyHC) mRNA for slow-twitch (SM), red fast-twitch (FRM) and white fast-twitch (FWM) myofibres. The body weight and lateral gastrocnemius weight were significantly lower in the ER group, accompanied by significantly reduced serum triiodothyronine. The ER group exhibited significantly higher SM and FRM MyHC expression at 14 d, but lower SM expression at 63 d. Myosin ATPase staining revealed a similar pattern. The percentage of SM was higher at 14 d while lower at 63 d in the ER group. These morphological changes were accompanied by changes of mRNA expression for growth-related genes. The ER group expressed lower insulin-like growth factoar I (IGF-I) and higher IGF-I receptor (IGF-IR) at 14 d, yet significantly increased growth hormone receptor and IGF-IR mRNA at 63 d. These results indicate that ER may delay the slow to fast myofibre conversion as an immediate effect, but would result in a lower percentage of slow fibres owing to compensatory growth in the long term, which involves changes of mRNA expression for the growth-related genes in the muscle.
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Affiliation(s)
- Yue Li
- Key Laboratory of Animal Physiology and Biochemistry, Nanjing Agricultural University, Nanjing, 210095, P. R. China
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Eizema K, van der Wal DE, van den Burg MMM, de Jonge HW, Everts ME. Differential Expression of Calcineurin and SR Ca2+ Handling Proteins in Equine Muscle Fibers During Early Postnatal Growth. J Histochem Cytochem 2006; 55:247-54. [PMID: 17101725 DOI: 10.1369/jhc.6a7039.2006] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
During early postnatal development, the myosin heavy chain (MyHC) expression pattern in equine gluteus medius muscle shows adaptation to movement and load, resulting in a decrease in the number of fast MyHC fibers and an increase in the number of slow MyHC fibers. In the present study we correlated the expression of MyHC isoforms to the expression of sarcoplasmic(endo)reticulum Ca2+-ATPase 1 and 2a (SERCA), phospholamban (PLB), calcineurin A (CnA), and calcineurin B (CnB). Gluteus medius muscle biopsies were taken at 0, 2, 4, and 48 weeks and analyzed using immunofluorescence. Both SERCA isoforms and PLB were expressed in almost all fiber types at birth. From 4 weeks of age onward, SERCA1 was exclusively expressed in fast MyHC fibers and SERCA2a and PLB in slow MyHC fibers. At all time points, CnA and CnB proteins were expressed at a basal level in all fibers, but with a higher expression level in MyHC type 1 fibers. From 4 weeks onward, expression of only CnA was also higher in MyHC type 2a and 2ad fibers. We propose a double function of calcineurin in calcium homeostasis and maintenance of slow MyHC fiber type identity. Although equine muscle is already functional at birth, expression patterns of the monitored proteins still show adaptation, depending on the MyHC fiber type.
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Affiliation(s)
- Karin Eizema
- Department of Pathobiology, Division of Anatomy and Physiology, Faculty of Veterinary Medicine, Utrecht University, P.O. Box 80.158, NL-3508 TD, Utrecht, The Netherlands.
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Abstract
Denervation changes in skeletal muscle (atrophy; alterations of myofibrillar expression, muscle membrane electrical properties, ACh sensitivity and excitation-contraction coupling process; fibrillation), and their possible causes are reviewed. All changes can be counteracted by muscle electrostimulation, while denervation-like effects can be caused by the complete conduction block in muscle nerve. These results do not support the hypothesis that the lack of neurotrophic, non-motor factors plays a role in denervation phenomena. Instead they support the view that the lack of neuromotor discharge is the only cause of the phenomena and that neuromotor activity is an essential factor in regulating muscle properties. However, some experimental results cannot apparently be explained by the lack of neuromotor impulses, and may still suggest that neurotrophic influences exist. A hypothesis is that neurotrophic factors, too feeble to maintain a role in completely differentiated, adult muscles, can concur with neuromotor activity in the differentiation of immature, developing muscles.
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Affiliation(s)
- Menotti Midrio
- Department of Human Anatomy and Physiology, Section of Physiology, University of Padua, via Marzolo 3, Padova, Italy.
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Issa LL, Palmer SJ, Guven KL, Santucci N, Hodgson VRM, Popovic K, Joya JE, Hardeman EC. MusTRD can regulate postnatal fiber-specific expression. Dev Biol 2006; 293:104-15. [PMID: 16494860 DOI: 10.1016/j.ydbio.2006.01.019] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2005] [Revised: 12/21/2005] [Accepted: 01/20/2006] [Indexed: 02/09/2023]
Abstract
Human MusTRD1alpha1 was isolated as a result of its ability to bind a critical element within the Troponin I slow upstream enhancer (TnIslow USE) and was predicted to be a regulator of slow fiber-specific genes. To test this hypothesis in vivo, we generated transgenic mice expressing hMusTRD1alpha1 in skeletal muscle. Adult transgenic mice show a complete loss of slow fibers and a concomitant replacement by fast IIA fibers, resulting in postural muscle weakness. However, developmental analysis demonstrates that transgene expression has no impact on embryonic patterning of slow fibers but causes a gradual postnatal slow to fast fiber conversion. This conversion was underpinned by a demonstrable repression of many slow fiber-specific genes, whereas fast fiber-specific gene expression was either unchanged or enhanced. These data are consistent with our initial predictions for hMusTRD1alpha1 and suggest that slow fiber genes contain a specific common regulatory element that can be targeted by MusTRD proteins.
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Affiliation(s)
- Laura L Issa
- Muscle Development Unit, Children's Medical Research Institute, Wentworthville, NSW 2145, Australia
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Abstract
We have previously demonstrated that p100H mutant mice, which lack a functional Sox6 gene, exhibit skeletal and cardiac muscle degeneration and develop cardiac conduction abnormalities soon after birth. To understand the role of Sox6 in skeletal muscle development, we identified muscle-specific genes differentially expressed between wild-type and p100H mutant skeletal muscles and investigated their temporal expression in the mutant muscle. We found that, in the mutant skeletal muscle, slow fiber and cardiac isoform genes are expressed at significantly higher levels, whereas fast fiber isoform genes are expressed at significantly lower levels than wild-type. Onset of this aberrant fiber type-specific gene expression in the mutant coincides with the beginning of the secondary myotube formation, at embryonic day 15-16 in mice. Together with our earlier report, demonstrating early postnatal muscle defects in the Sox6 null-p100H mutant, the present results suggest that Sox6 likely plays an important role in muscle development.
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Affiliation(s)
- Nobuko Hagiwara
- University of California, Davis, Division of Cardiovascular Medicine, Rowe Program in Genetics, Davis, CA 95616, USA
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de Jonge HW, van der Wiel CW, Eizema K, Weijs WA, Everts ME. Presence of SERCA and calcineurin during fetal development of porcine skeletal muscle. J Histochem Cytochem 2006; 54:641-8. [PMID: 16714421 DOI: 10.1369/jhc.5a6812.2006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Mechanisms involved in skeletal myofiber differentiation during fetal development of large animals are poorly understood. Studies in small animals suggest that the calcineurin (Cn) pathway is involved in myofiber differentiation. Neural activity is a prerequisite for Cn activity, implying maintenance of sustained low intracellular Ca(2+) concentrations. To study the role of Cn in fetal myofiber differentiation, we monitored the temporal and spatial distribution of Cn subunits, sarcoplasmic reticulum Ca(2+) ATPase (SERCA), phospholamban (PLB), and myosin heavy chain (MyHC) isoforms in relation to ingrowing nerves in porcine semitendinosus muscle (m. semitendinosus) at 55 and 75 days of gestation (dg) and at term. Immunofluorescence analysis revealed the presence of Cn subunits and SERCA isoforms at all analyzed stages. Cn distribution was not fiber-type specific, but expression became more prominent at term. At 75 dg, differential SERCA2 expression was accompanied by perinuclear PLB in primary fibers. SERCA1 was expressed in all fiber types at all stages. No specific MyHC isoform distribution was seen in relation to neuromuscular contacts, although neuromuscular contacts were present. From these results we speculate that in porcine m. semitendinosus differential SERCA2 expression precedes differential Cn expression. The question whether the Cn pathway is involved in prenatal myofiber differentiation needs further studies.
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Affiliation(s)
- Henriëtte W de Jonge
- Division of Anatomy and Physiology, Department of Pathobiology, Faculty of Veterinary Medicine, Utrecht University, PO Box 80.158, NL-3508 TD, Utrecht, The Netherlands.
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Brotto MA, Biesiadecki BJ, Brotto LS, Nosek TM, Jin JP. Coupled expression of troponin T and troponin I isoforms in single skeletal muscle fibers correlates with contractility. Am J Physiol Cell Physiol 2005; 290:C567-76. [PMID: 16192301 PMCID: PMC1409758 DOI: 10.1152/ajpcell.00422.2005] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Striated muscle contraction is powered by actin-activated myosin ATPase. This process is regulated by Ca(2+) via the troponin complex. Slow- and fast-twitch fibers of vertebrate skeletal muscle express type I and type II myosin, respectively, and these myosin isoenzymes confer different ATPase activities, contractile velocities, and force. Skeletal muscle troponin has also diverged into fast and slow isoforms, but their functional significance is not fully understood. To investigate the expression of troponin isoforms in mammalian skeletal muscle and their functional relationship to that of the myosin isoforms, we concomitantly studied myosin, troponin T (TnT), and troponin I (TnI) isoform contents and isometric contractile properties in single fibers of rat skeletal muscle. We characterized a large number of Triton X-100-skinned single fibers from soleus, diaphragm, gastrocnemius, and extensor digitorum longus muscles and selected fibers with combinations of a single myosin isoform and a single class (slow or fast) of the TnT and TnI isoforms to investigate their role in determining contractility. Types IIa, IIx, and IIb myosin fibers produced higher isometric force than that of type I fibers. Despite the polyploidy of adult skeletal muscle fibers, the expression of fast or slow isoforms of TnT and TnI is tightly coupled. Fibers containing slow troponin had higher Ca(2+) sensitivity than that of the fast troponin fibers, whereas fibers containing fast troponin showed a higher cooperativity of Ca(2+) activation than that of the slow troponin fibers. These results demonstrate distinct but coordinated regulation of troponin and myosin isoform expression in skeletal muscle and their contribution to the contractile properties of muscle.
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Affiliation(s)
- Marco A Brotto
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA
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Polly P, Haddadi LM, Issa LL, Subramaniam N, Palmer SJ, Tay ESE, Hardeman EC. hMusTRD1alpha1 represses MEF2 activation of the troponin I slow enhancer. J Biol Chem 2003; 278:36603-10. [PMID: 12857748 DOI: 10.1074/jbc.m212814200] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The novel transcription factor hMusTRD1alpha1 (human muscle TFII-I repeat domain-containing protein 1alpha1; previously named MusTRD1; O'Mahoney, J. V., Guven, K. L., Lin, J., Joya, J. E., Robinson, C. S., Wade, R. P., and Hardeman, E. C. (1998) Mol. Cell. Biol. 18, 6641-6652) was identified in a yeast one-hybrid screen as a protein that binds within an upstream enhancer-containing region of the skeletal muscle-specific gene, TNNI1 (human troponin I slow; hTnIslow). It has been proposed that hMusTRD1alpha1 may play an important role in fiber-specific muscle gene expression by virtue of its ability to bind to an Inr-like element (nucleotides -977 to -960) within the hTnIslow upstream enhancer-containing region that is necessary for slow fiber-specific expression. In this study we demonstrate that both MEF2C, a known regulator of slow fiber-specific genes, and hMusTRD1alpha1 regulate hTnIslow through the Inr-like element. Co-transfection assays in C2C12 cells and Cos-7 cells demonstrate that hMusTRD1alpha1 represses hTnIslow transcription and prevents MEF2C-mediated activation of hTnIslow transcription. Gel shift analysis shows that hMusTRD1alpha1 can abrogate MEF2C binding to its cognate site in the hTnIslow enhancer. Glutathione S-transferase pull-down assays demonstrate that hMusTRD1alpha1 can interact with both MEF2C and the nuclear receptor co-repressor. The data support the role of hMusTRD1alpha1 as a repressor of slow fiber-specific transcription through mechanisms involving direct interactions with MEF2C and the nuclear receptor co-repressor.
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Affiliation(s)
- Patsie Polly
- Muscle Development Unit, Children's Medical Research Institute, Wentworthville, New South Wales 2145, Australia
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Tay ESE, Guven KL, Subramaniam N, Polly P, Issa LL, Gunning PW, Hardeman EC. Regulation of alternative splicing of Gtf2ird1 and its impact on slow muscle promoter activity. Biochem J 2003; 374:359-67. [PMID: 12780350 PMCID: PMC1223606 DOI: 10.1042/bj20030189] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2003] [Revised: 05/12/2003] [Accepted: 06/03/2003] [Indexed: 11/17/2022]
Abstract
A human MusTRD (muscle TFII-I repeat domain (RD)-containing protein) isoform was originally identified in a yeast one-hybrid screen as a protein that binds the slow fibre-specific enhancer of the muscle gene troponin I slow [O'Mahoney, Guven, Lin, Joya, Robinson, Wade and Hardeman (1998) Mol. Cell. Biol. 18, 6641-6652]. MusTRD shares homology with the general transcription factor TFII-I by the presence of diagnostic I-RDs [Roy (2001) Gene 274, 1-13]. The human gene encoding MusTRD, GTF2IRD1 ( WBSCR11 / GTF3 ), was subsequently located on chromosome 7q11.23, a region deleted in the neurodegenerative disease, Williams-Beuren Syndrome [Osborne, Campbell, Daradich, Scherer, Tsui, Franke, Peoples, Francke, Voit, Kramer et al. (1999) Genomics 57, 279-284; Franke, Peoples and Francke (1999) Cytogenet. Cell. Genet. 86, 296-304; Tassabehji, Carette, Wilmot, Donnai, Read and Metcalfe (1999) Eur. J. Hum. Genet. 7, 737-747]. The haploinsufficiency of MusTRD has been implicated in the myopathic aspect of this disease, which manifests itself in symptoms such as lowered resistance to fatigue, kyphoscoliosis, an abnormal gait and joint contractures [Tassabehji, Carette, Wilmot, Donnai, Read and Metcalfe (1999) Eur. J. Hum. Genet. 7, 737-747]. Here, we report the identification of 11 isoforms of MusTRD in mouse skeletal muscles. These isoforms were isolated from a mouse skeletal muscle cDNA library and reverse transcription-PCR on RNA from various adult and embryonic muscles. The variability in these isoforms arises from alternative splicing of a combination of four cassettes and two mutually exclusive exons, all in the 3' region of the primary transcript of Gtf2ird1, the homologous mouse gene. The expression of some of these isoforms is differentially regulated spatially, suggesting individual regulation of the expression of these isoforms. Co-transfection studies in C2C12 muscle cell cultures reveal that isoforms differentially regulate muscle fibre-type-specific promoters. This indicates that the presence of different domains of MusTRD influences the activity exerted by this molecule on multiple promoters active in skeletal muscle.
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Affiliation(s)
- Enoch S E Tay
- Muscle Development Unit, Children's Medical Research Institute, Locked Bag 23, Westmead, NSW 2145, Australia
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45
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Abstract
In the last 10 years an increasing number of studies have provided an insight in the signalling mechanisms underlying myogenesis and fibre type specification during embryonic development: this paper aims to review the most relevant findings. In vertebrates a central role in muscle differentiation is played by the MyoD family, a group of transcription factors which activate transcription of muscle specific genes. In turn MyoD family is expressed in response to inductive signals coming from tissues adjacent to somites, in the first place the notochord and the neural tube. Hedgehog and Wnt are among these inductive signals and they find in the future myoblasts a response pathway which includes Ptc, Smu and Gli. The signalling mechanisms have been analysed in model organisms: mouse, chick. zebrafish and Drosophila. For some factors the orthologs in different species have been found to accomplish similar function, but for some other factors important differences are present: for example in Drosophila twist codes for a transcription factor which promotes myogenesis, whereas its ortholog in mouse tends to prevent or inhibit myogenesis. Conversely, nautilus which is the orholog of MyoD in Drosophila does not have a general function in muscle differentiation, but is required for the differentiation of a limited group of muscle fibres.
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Chin ER, Grange RW, Viau F, Simard AR, Humphries C, Shelton J, Bassel-Duby R, Williams RS, Michel RN. Alterations in slow-twitch muscle phenotype in transgenic mice overexpressing the Ca2+ buffering protein parvalbumin. J Physiol 2003; 547:649-63. [PMID: 12562945 PMCID: PMC2342652 DOI: 10.1113/jphysiol.2002.024760] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
The purpose of this study was to determine whether induced expression of the Ca2+ buffering protein parvalbumin (PV) in slow-twitch fibres would lead to alterations in physiological, biochemical and molecular properties reflective of a fast fibre phenotype. Transgenic (TG) mice were generated that overexpressed PV in slow (type I) muscle fibres. In soleus muscle (SOL; 58 % type I fibres) total PV expression was 2- to 6-fold higher in TG compared to wild-type (WT) mice. Maximum twitch and tetanic tensions were similar in WT and TG but force at subtetanic frequencies (30 and 50 Hz) was reduced in TG SOL. Twitch time-to-peak tension and half-relaxation time were significantly decreased in TG SOL (time-to-peak tension: 39.3 +/- 2.6 vs. 55.1 +/- 4.7 ms; half-relaxation time: 42.1 +/- 3.5 vs. 68.1 +/- 9.6 ms, P < 0.05 for TG vs. WT, respectively; n = 8-10). There was a significant increase in expression of type IIa myosin heavy chain (MHC) and ryanodine receptor at the mRNA level in TG SOL but there were no differences in MHC expression at the protein level and thus no difference in fibre type. Whole muscle succinate dehydrogenase activity was reduced by 12 +/- 0.4 % in TG SOL and single fibre glycerol-3-phosphate dehydrogenase activity was decreased in a subset of type IIa fibres. These differences were associated with a 64 % reduction in calcineurin activity in TG SOL. These data show that overexpression of PV, resulting in decreased calcineurin activity, can alter the functional and metabolic profile of muscle and influence the expression of key marker genes in a predominantly slow-twitch muscle with minimal effects on the expression of muscle contractile proteins.
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Affiliation(s)
- Eva R Chin
- Department of Internal Medicine, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, NB11.200, Dallas, TX 75235-8573, USA.
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47
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Abstract
The cells of the electric organ, called electrocytes, of the weakly electric fish Sternopygus macrurus derive from the fusion of mature fast muscle fibers that subsequently disassemble and downregulate their sarcomeric components. Previously, we showed a reversal of the differentiated state of electrocytes to that of their muscle fiber precursors when neural input is eliminated. The dependence of the mature electrocyte phenotype on neural input led us to test the hypothesis that innervation is also critical during formation of electrocytes. We used immunohistochemical analyses to examine the regeneration of skeletal muscle and electric organ in the presence or absence of innervation. We found that blastema formation is a nerve-dependent process because regeneration was minimal when tail amputation and denervation were performed at the same time. Denervation at the onset of myogenesis resulted in the differentiation of both fast and slow muscle fibers. These were fewer in number, but in a spatial distribution similar to controls. However, in the absence of innervation, fast muscle fibers did not progress beyond the formation of closely apposed clusters, suggesting that innervation is required for their fusion and subsequent transdifferentiation into electrocytes. This study contributes further to our knowledge of the influence of innervation on cell differentiation in the myogenic lineage.
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Affiliation(s)
- Graciela A Unguez
- Department of Biology, New Mexico State University, Foster Hall, Las Cruces, NM 88003, USA.
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48
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Spitz F, Benbacer L, Sabourin JC, Salminen M, Chen F, Cywiner C, Kahn A, Chatelet F, Maire P, Daegelen D. Fiber-type specific and position-dependent expression of a transgene in limb muscles. Differentiation 2002; 70:457-67. [PMID: 12366383 DOI: 10.1046/j.1432-0436.2002.700808.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
We have previously shown that the proximal sequences of the human aldolase A fast-muscle-specific promoter (pM) are sufficient to target the expression of a linked CAT reporter gene to all fast, glycolytic trunk and limb muscles of transgenic mice (pM310CAT lines) in a manner mimicking the activity of the endogenous mouse promoter. When a NF1-binding site (motif M2) in this proximal regulatory region is mutated, the activity of the corresponding mM2 transgene is strongly affected but only in a some fast muscles. Here we show that the mutation of the M2 motif has only mild effects on pM activity in axial and proximal limb, while it drastically reduces this activity in both fore and hind limb distal muscles. At the cellular level, we show that both the pM310CAT and mM2 transgenes are highly expressed in fast glycolytic 2B fibers. However, by contrast to the pM310CAT transgene, whose expression is mainly restricted to fast glycolytic 2B fibers, the mM2 transgene is also active in a high proportion of 2X fibers. This result suggests that the M2 sequence could play a role in restricting the expression of pM to the 2B fibers. The variable expression of the mM2 transgene along the limb axis already exists at post-natal day 10 and seems to result from a change in the proportion of expressing fast fibers per muscle. Altogether, these results suggest that, although considered as phenotypically similar, different populations of fast glycolytic fibers exist, in which the requirement of the NF1 activity for pM expression varies according to the proximal versus distal position of the muscle along the limb axis.
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Affiliation(s)
- François Spitz
- INSERM U567, CNRS UMR 8104, Institut Cochin; Department Génétique, Développement et Pathologie Moléculaire, Universiteé René Descartes Paris V, 24 rue du Faubourg Saint Jacques, 75014 Paris
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49
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Abstract
Mammalian skeletal muscles are a mosaic of different fiber types largely defined by differential myosin heavy chain (MyHC) expression. Little is known about the molecular mechanisms regulating expression of the MyHC gene family members in different fiber types. In this work, we identified several cis- and trans-elements that regulate expression of the three adult fast MyHC genes. Despite multiple DNA-binding motifs for well characterized muscle transcription factors upstream of all three fast MyHC genes, expression of MyoD/Myf-5, calcineurin, or NFAT3 had different effects on the three promoters. MyoD or Myf-5 overexpression preferentially activated the IIb promoter, whereas NFAT or activated calcineurin overexpression preferentially activated the IIa promoter. Calcineurin had a 50-100-fold stimulatory effect on the IIa promoter, and the known downstream effectors of calcineurin (myocyte enhancer factor-2 and NFAT) cannot completely account for this activation. Finally, we identified two elements critical for regulating MyHC-IId/x expression: a 130-base pair enhancer element and a CArG-like element that inhibited IId/x promoter activity in vitro. Thus, we have found specific regulatory pathways that are distinct for the three adult fast MyHC genes. These elements are logical candidates for fiber-specific control of skeletal muscle gene expression in vivo.
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Affiliation(s)
- D L Allen
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, Colorado 80309-0347, USA
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50
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Abstract
The molecular regulation of muscle development is tightly controlled at three distinct stages of the process: determination, differentiation, and maturation. Developmentally, specific populations of myoblasts exhibit distinct molecular phenotypes that begin to limit the ultimate characteristics of the muscle fibers. The expression of the myogenic regulatory factor family of the transcription process plays a key role in muscle development and, ultimately, in the subset of contractile genes expressed in a specific muscle. Craniofacial muscles have distinct functional requirements and associated molecular phenotypes that distinguish them from other skeletal muscles. The general principles of muscle molecular differentiation with specific reference to craniofacial muscles, such as the tongue, are discussed in this review.
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Affiliation(s)
- C F Shuler
- University of Southern California, Center for Craniofacial Molecular Biology, Los Angeles 90033, USA
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