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Rönnblom A, Thornell L, Shah F, Tano K, Stål P. Unique fiber phenotype composition and metabolic properties of the stapedius and tensor tympani muscles in the human middle ear. J Anat 2023; 243:39-50. [PMID: 36914412 PMCID: PMC10273355 DOI: 10.1111/joa.13861] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Revised: 01/19/2023] [Accepted: 02/16/2023] [Indexed: 03/14/2023] Open
Abstract
The middle ear muscles have vital roles, yet their precise function in hearing and protection remains unclear. To better understand the function of these muscles in humans, the morphology, fiber composition, and metabolic properties of nine tensor tympani and eight stapedius muscles were analyzed with immunohistochemical, enzyme-histochemical, biochemical, and morphometric techniques. Human orofacial, jaw, extraocular, and limb muscles were used as references. The immunohistochemical analysis showed that the stapedius and tensor tympani muscles were markedly dominated by fibers expressing fast contracting myosin heavy chain MyHC-2A and MyHC-2X (79 ± 6% vs. 86 ± 9%, respectively, p = 0.04). In fact, the middle ear muscles had one of the highest proportions of MyHC-2 fibers ever reported for human muscles. Interestingly, the biochemical analysis revealed a MyHC isoform of unknown identity in both the stapedius and tensor tympani muscles. Muscle fibers containing two or more MyHC isoforms were relatively frequently observed in both muscles. A proportion of these hybrid fibers expressed a developmental MyHC isoform that is normally absent in adult human limb muscles. The middle ear muscles differed from orofacial, jaw, and limb muscles by having significantly smaller fibers (220 vs. 360 μm2 , respectively) and significantly higher variability in fiber size, capillarization per fiber area, mitochondrial oxidative activity, and density of nerve fascicles. Muscle spindles were observed in the tensor tympani muscle but not in the stapedius muscle. We conclude that the middle ear muscles have a highly specialized muscle morphology, fiber composition, and metabolic properties that generally showed more similarities to orofacial than jaw and limb muscles. Although the muscle fiber characteristics in the tensor tympani and stapedius muscles suggest a capacity for fast, fine-tuned, and sustainable contractions, their difference in proprioceptive control reflects different functions in hearing and protection of the inner ear.
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Affiliation(s)
- Anton Rönnblom
- Department of Clinical Science, Otorhinolaryngology/Sunderby Research UnitUmeå UniversityUmeåSweden
| | - Lars‐Eric Thornell
- Department of Integrative Medical Biology, Laboratory of Muscle BiologyUmeå UniversityUmeåSweden
| | - Farhan Shah
- Department of Integrative Medical Biology, Laboratory of Muscle BiologyUmeå UniversityUmeåSweden
| | - Krister Tano
- Department of Clinical Science, Otorhinolaryngology/Sunderby Research UnitUmeå UniversityUmeåSweden
| | - Per Stål
- Department of Integrative Medical Biology, Laboratory of Muscle BiologyUmeå UniversityUmeåSweden
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2
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Hitachi K, Kiyofuji Y, Yamaguchi H, Nakatani M, Inui M, Tsuchida K. Simultaneous loss of skeletal muscle myosin heavy chain IIx and IIb causes severe skeletal muscle hypoplasia in postnatal mice. FASEB J 2023; 37:e22692. [PMID: 36515178 DOI: 10.1096/fj.202200581r] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Revised: 11/09/2022] [Accepted: 11/22/2022] [Indexed: 12/15/2022]
Abstract
The skeletal muscle myosin heavy chain (MyHC) is a fundamental component of the sarcomere structure and muscle contraction. Two of the three adult fast MyHCs, MyHC-IIx and MyHC-IIb, are encoded by Myh1 and Myh4, respectively. However, skeletal muscle disorders have not yet been linked to these genes in humans. MyHC-IIb is barely detectable in human skeletal muscles. Thus, to characterize the molecular function of skeletal muscle MyHCs in humans, investigation of the effect of simultaneous loss of MyHC-IIb and other MyHCs on skeletal muscle in mice is essential. Here, we generated double knockout (dKO) mice with simultaneous loss of adult fast MyHCs by introducing nonsense frameshift mutations into the Myh1 and Myh4 genes. The dKO mice appeared normal after birth and until 2 weeks of age but showed severe skeletal muscle hypoplasia after 2 weeks. In 3-week-old dKO mice, increased expression of other skeletal muscle MyHCs, such as MyHC-I, MyHC-IIa, MyHC-neo, and MyHC-emb, was observed. However, these expressions were not sufficient to compensate for the loss of MyHC-IIb and MyHC-IIx. Moreover, the aberrant sarcomere structure with altered expression of sarcomere components was observed in dKO mice. Our findings imply that the simultaneous loss of MyHC-IIb and MyHC-IIx is substantially detrimental to postnatal skeletal muscle function and will contribute to elucidating the molecular mechanisms of skeletal muscle wasting disorders caused by the loss of skeletal muscle MyHCs.
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Affiliation(s)
- Keisuke Hitachi
- Division for Therapies against Intractable Diseases, Institute for Comprehensive Medical Science (ICMS), Fujita Health University, Toyoake, Japan
| | - Yuri Kiyofuji
- Division for Therapies against Intractable Diseases, Institute for Comprehensive Medical Science (ICMS), Fujita Health University, Toyoake, Japan
| | - Hisateru Yamaguchi
- School of Nursing and Medical Care, Yokkaichi Nursing and Medical Care University, Yokkaichi, Japan
| | - Masashi Nakatani
- Faculty of Rehabilitation and Care, Seijoh University, Tokai, Japan
| | - Masafumi Inui
- Laboratory of Animal Regeneration Systemology, Department of Life Sciences, School of Agriculture, Meiji University, Kawasaki, Japan
| | - Kunihiro Tsuchida
- Division for Therapies against Intractable Diseases, Institute for Comprehensive Medical Science (ICMS), Fujita Health University, Toyoake, Japan
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3
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Pandorf CE, Haddad F, Owerkowicz T, Carroll LP, Baldwin KM, Adams GR. Regulation of myosin heavy chain antisense long noncoding RNA in human vastus lateralis in response to exercise training. Am J Physiol Cell Physiol 2020; 318:C931-C942. [PMID: 32130073 DOI: 10.1152/ajpcell.00166.2018] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Alterations to muscle activity or loading state can induce changes in expression of myosin heavy chain (MHC). For example, sedentary individuals that initiate exercise training can induce a pronounced shift from IIx to IIa MHC. We sought to examine the regulatory response of MHC RNA in human subjects in response to exercise training. In particular, we examined how natural antisense RNA transcripts (NATs) are regulated throughout the MHC gene locus that includes MYH2 (IIa), MYH1 (IIx), MYH4 (IIb), and MYH8 (Neonatal) in vastus lateralis before and after a 5-wk training regime that consisted of a combination of aerobic and resistance types of exercise. The exercise program induced a IIx to IIa MHC shift that was associated with a corresponding increase in transcription on the antisense strand of the IIx MHC gene and a decrease in antisense transcription of the IIa MHC gene, suggesting an inhibitory mechanism mediated by NATs. We also report that the absence of expression of IIb MHC in human limb muscle is associated with the abundant expression of antisense transcript overlapping the IIb MHC coding gene, which is the opposite expression pattern as compared with that previously observed in rats. The NAT provides a possible regulatory mechanism for the suppressed expression of IIb MHC in humans. These data indicate that NATs may play a regulatory role with regard to the coordinated shifts in MHC gene expression that occur in human muscle in response to exercise training.
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Affiliation(s)
- Clay E Pandorf
- Department of Biomedical Sciences, Mercer University School of Medicine, Macon, Georgia
| | - Fadia Haddad
- Department of Physiology and Biophysics, School of Medicine, University of California, Irvine, California
| | - Tomasz Owerkowicz
- Department of Biology, California State University, San Bernardino, California
| | - Leslie P Carroll
- Department of Biomedical Sciences, Mercer University School of Medicine, Macon, Georgia
| | - Kenneth M Baldwin
- Department of Physiology and Biophysics, School of Medicine, University of California, Irvine, California
| | - Gregory R Adams
- Department of Physiology and Biophysics, School of Medicine, University of California, Irvine, California
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4
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Isola G, Matarese G. Response to Letter to the Editor "A window to consolidate the 'functional hypothesis of bruxism' through cardiovascular autonomic link". Oral Dis 2019; 25:1239-1240. [PMID: 30828901 DOI: 10.1111/odi.13078] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Accepted: 02/27/2019] [Indexed: 02/05/2023]
Affiliation(s)
- Gaetano Isola
- Department of General Surgery and Surgical-Medical Specialties, University of Catania, Catania, Italy
| | - Giovanni Matarese
- Department of Biomedical, Odontostomatological Sciences and of Morphological and Functional Images, University of Messina, Messina, Italy
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5
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Lee LA, Karabina A, Broadwell LJ, Leinwand LA. The ancient sarcomeric myosins found in specialized muscles. Skelet Muscle 2019; 9:7. [PMID: 30836986 PMCID: PMC6402096 DOI: 10.1186/s13395-019-0192-3] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2019] [Accepted: 02/22/2019] [Indexed: 12/17/2022] Open
Abstract
Striated muscles express an array of sarcomeric myosin motors that are tuned to accomplish specific tasks. Each myosin isoform found in muscle fibers confers unique contractile properties to the fiber in order to meet the demands of the muscle. The sarcomeric myosin heavy chain (MYH) genes expressed in the major cardiac and skeletal muscles have been studied for decades. However, three ancient myosins, MYH7b, MYH15, and MYH16, remained uncharacterized due to their unique expression patterns in common mammalian model organisms and due to their relatively recent discovery in these genomes. This article reviews the literature surrounding these three ancient sarcomeric myosins and the specialized muscles in which they are expressed. Further study of these ancient myosins and how they contribute to the functions of the specialized muscles may provide novel insight into the history of striated muscle evolution.
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Affiliation(s)
- Lindsey A. Lee
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, CO USA
- BioFrontiers Institute, University of Colorado, Boulder, CO USA
| | - Anastasia Karabina
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, CO USA
- BioFrontiers Institute, University of Colorado, Boulder, CO USA
| | - Lindsey J. Broadwell
- BioFrontiers Institute, University of Colorado, Boulder, CO USA
- Department of Biochemistry, University of Colorado, Boulder, CO USA
| | - Leslie A. Leinwand
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, CO USA
- BioFrontiers Institute, University of Colorado, Boulder, CO USA
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6
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Isola G, Anastasi GP, Matarese G, Williams RC, Cutroneo G, Bracco P, Piancino MG. Functional and molecular outcomes of the human masticatory muscles. Oral Dis 2018; 24:1428-1441. [PMID: 29156093 DOI: 10.1111/odi.12806] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Revised: 10/30/2017] [Accepted: 11/14/2017] [Indexed: 02/05/2023]
Abstract
The masticatory muscles achieve a broad range of different activities such as chewing, sucking, swallowing, and speech. In order to accomplish these duties, masticatory muscles have a unique and heterogeneous structure and fiber composition, enabling them to produce their strength and contraction speed largely dependent on their motor units and myosin proteins that can change in response to genetic and environmental factors. Human masticatory muscles express unique myosin isoforms, including a combination of thick fibers, expressing myosin light chains (MyLC) and myosin class I and II heavy chains (MyHC) -IIA, -IIX, α-cardiac, embryonic and neonatal and thin fibers, respectively. In this review, we discuss the current knowledge regarding the importance of fiber-type diversity in masticatory muscles versus supra- and infrahyoid muscles, and versus limb and trunk muscles. We also highlight new information regarding the adaptive response and specific genetic variations of muscle fibers on the functional significance of the masticatory muscles, which influences craniofacial characteristics, malocclusions, or asymmetry. These findings may offer future possibilities for the prevention of craniofacial growth disturbances.
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Affiliation(s)
- G Isola
- Department of Biomedical, Odontostomatological Sciences and of Morphological and Functional Images, School of Dentistry, University of Messina, Messina, Italy
| | - G P Anastasi
- Department of Biomedical, Odontostomatological Sciences and of Morphological and Functional Images, School of Dentistry, University of Messina, Messina, Italy
| | - G Matarese
- Department of Biomedical, Odontostomatological Sciences and of Morphological and Functional Images, School of Dentistry, University of Messina, Messina, Italy
| | - R C Williams
- Department of Periodontology, UNC School of Dentistry, Chapel Hill, NC, USA
| | - G Cutroneo
- Department of Biomedical, Odontostomatological Sciences and of Morphological and Functional Images, School of Dentistry, University of Messina, Messina, Italy
| | - P Bracco
- Department of Orthodontics and Gnathology-Masticatory Function, University of Turin, Turin, Italy
| | - M G Piancino
- Department of Orthodontics and Gnathology-Masticatory Function, University of Turin, Turin, Italy
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7
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Expression of MyHC isoforms mRNA transcripts in different regions of the masseter and medial pterygoid muscles in chimpanzees. Arch Oral Biol 2017; 83:63-67. [DOI: 10.1016/j.archoralbio.2017.07.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2016] [Revised: 06/27/2017] [Accepted: 07/06/2017] [Indexed: 11/22/2022]
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8
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Korfage JAM, Koolstra JH, Langenbach GEJ, van Eijden TMGJ. Fiber-type Composition of the Human Jaw Muscles—(Part 1) Origin and Functional Significance of Fiber-type Diversity. J Dent Res 2016; 84:774-83. [PMID: 16109984 DOI: 10.1177/154405910508400901] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
This is the first of two articles on the fiber-type composition of the human jaw muscles. The present article discusses the origin of fiber-type composition and its consequences. This discussion is presented in the context of the requirements for functional performance and adaptation that are imposed upon the jaw muscles. The human masticatory system must perform a much larger variety of motor tasks than the average limb or trunk motor system. An important advantage of fiber-type diversity, as observed in the jaw muscles, is that it optimizes the required function while minimizing energy use. The capacity for adaptation is reflected by the large variability in fiber-type composition among muscle groups, individual muscles, and muscle regions. Adaptive changes are related, for example, to the amount of daily activation and/or stretch of fibers. Generally, the number of slow, fatigue-resistant fibers is relatively large in muscles and muscle regions that are subjected to considerable activity and/or stretch.
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Affiliation(s)
- J A M Korfage
- Department of Functional Anatomy, Academic Center for Dentistry Amsterdam, Meibergdreef 15, 1105 AZ Amsterdam, The Netherlands
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9
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Mascarello F, Toniolo L, Cancellara P, Reggiani C, Maccatrozzo L. Expression and identification of 10 sarcomeric MyHC isoforms in human skeletal muscles of different embryological origin. Diversity and similarity in mammalian species. Ann Anat 2016; 207:9-20. [PMID: 26970499 DOI: 10.1016/j.aanat.2016.02.007] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Accepted: 02/15/2016] [Indexed: 10/22/2022]
Abstract
In the mammalian genome, among myosin heavy chain (MyHC) isoforms a family can be identified as sarcomeric based on their molecular structure which allows thick filament formation. In this study we aimed to assess the expression of the 10 sarcomeric isoforms in human skeletal muscles, adopting this species as a reference for comparison with all other mammalian species. To this aim, we set up the condition for quantitative Real Time PCR assay to detect and quantify MyHC mRNA expression in a wide variety of human muscles from somitic, presomitic and preotic origin. Specific patterns of expression of the following genes MYH1, MYH2, MYH3, MYH4, MYH6, MYH7, MYH8, MYH13, MYH14/7b and MYH15 were demonstrated in various muscle samples. On the same muscle samples which were analysed for mRNA expression, the corresponding MyHC proteins were studied with SDS PAGE and Western blot. The mRNA-protein comparison allowed the identification of 10 distinct proteins based on the electrophoretic migration rate. Three groups were formed based on the migration rate: fast migrating comprising beta/slow/1, alpha cardiac and fast 2B, slow migrating comprising fast 2X, fast 2A and two developmental isoforms (NEO and EMB), intermediate migrating comprising EO MyHC, slow B (product of MYH15), slow tonic (product of MYH14/7b). Of special interest was the demonstration of a protein band corresponding to 2B-MyHC in laryngeal muscles and the finding that all 10 isoforms are expressed in extraocular muscles. These latter muscles are the unique localization for extraocular, slow B (product of MYH15) and slow tonic (product of MYH14/7b).
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Affiliation(s)
- Francesco Mascarello
- Department of Comparative Biomedicine and Food Science, University of Padova, viale dell'Università 16, Legnaro, 35020 Padova, Italy.
| | - Luana Toniolo
- Department of Biomedical Sciences, University of Padova Via Marzolo 3, 35131 Padova, Italy
| | - Pasqua Cancellara
- Department of Biomedical Sciences, University of Padova Via Marzolo 3, 35131 Padova, Italy
| | - Carlo Reggiani
- Department of Biomedical Sciences, University of Padova Via Marzolo 3, 35131 Padova, Italy
| | - Lisa Maccatrozzo
- Department of Comparative Biomedicine and Food Science, University of Padova, viale dell'Università 16, Legnaro, 35020 Padova, Italy
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10
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Chen L, Zhang YH, Huang T, Cai YD. Identifying novel protein phenotype annotations by hybridizing protein-protein interactions and protein sequence similarities. Mol Genet Genomics 2016; 291:913-34. [PMID: 26728152 DOI: 10.1007/s00438-015-1157-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Accepted: 12/08/2015] [Indexed: 01/18/2023]
Abstract
Studies of protein phenotypes represent a central challenge of modern genetics in the post-genome era because effective and accurate investigation of protein phenotypes is one of the most critical procedures to identify functional biological processes in microscale, which involves the analysis of multifactorial traits and has greatly contributed to the development of modern biology in the post genome era. Therefore, we have developed a novel computational method that identifies novel proteins associated with certain phenotypes in yeast based on the protein-protein interaction network. Unlike some existing network-based computational methods that identify the phenotype of a query protein based on its direct neighbors in the local network, the proposed method identifies novel candidate proteins for a certain phenotype by considering all annotated proteins with this phenotype on the global network using a shortest path (SP) algorithm. The identified proteins are further filtered using both a permutation test and their interactions and sequence similarities to annotated proteins. We compared our method with another widely used method called random walk with restart (RWR). The biological functions of proteins for each phenotype identified by our SP method and the RWR method were analyzed and compared. The results confirmed a large proportion of our novel protein phenotype annotation, and the RWR method showed a higher false positive rate than the SP method. Our method is equally effective for the prediction of proteins involving in all the eleven clustered yeast phenotypes with a quite low false positive rate. Considering the universality and generalizability of our supporting materials and computing strategies, our method can further be applied to study other organisms and the new functions we predicted can provide pertinent instructions for the further experimental verifications.
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Affiliation(s)
- Lei Chen
- School of Life Sciences, Shanghai University, Shanghai, 200444, People's Republic of China. .,College of Information Engineering, Shanghai Maritime University, Shanghai, 201306, People's Republic of China.
| | - Yu-Hang Zhang
- Institute of Health Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, 200031, People's Republic of China
| | - Tao Huang
- Institute of Health Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, 200031, People's Republic of China
| | - Yu-Dong Cai
- School of Life Sciences, Shanghai University, Shanghai, 200444, People's Republic of China.
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11
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He X, Duan Y, Yao K, Li F, Hou Y, Wu G, Yin Y. β-Hydroxy-β-methylbutyrate, mitochondrial biogenesis, and skeletal muscle health. Amino Acids 2015; 48:653-664. [PMID: 26573541 DOI: 10.1007/s00726-015-2126-7] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2015] [Accepted: 11/02/2015] [Indexed: 12/16/2022]
Abstract
The metabolic roles of mitochondria go far beyond serving exclusively as the major producer of ATP in tissues and cells. Evidence has shown that mitochondria may function as a key regulator of skeletal muscle fiber types and overall well-being. Maintaining skeletal muscle mitochondrial content and function is important for sustaining health throughout the lifespan. Of great importance, β-hydroxy-β-methylbutyrate (HMB, a metabolite of L-leucine) has been proposed to enhance the protein deposition and efficiency of mitochondrial biogenesis in skeletal muscle, as well as muscle strength in both exercise and clinical settings. Specifically, dietary supplementation with HMB increases the gene expression of peroxisome proliferator-activated receptor gamma co-activator 1-alpha (PGC-1α), which represents an upstream inducer of genes of mitochondrial metabolism, coordinates the expression of both nuclear- and mitochondrion-encoded genes in mitochondrial biogenesis. Additionally, PGC-1α plays a key role in the transformation of skeletal muscle fiber type, leading to a shift toward type I muscle fibers that are rich in mitochondria and have a high capacity for oxidative metabolism. As a nitrogen-free metabolite, HMB holds great promise to improve skeletal muscle mass and function, as well as whole-body health and well-being of animals and humans.
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Affiliation(s)
- Xi He
- College of Animal Science and Technology, Hunan Agricultural University, Changsha, 410128, China.,Hunan Co-Innovation Center of Animal Production Safety, Changsha, 410128, China
| | - Yehui Duan
- Scientific Observation and Experiment Station of Animal Nutrition and Feed Science in South-Central China, Ministry of Agriculture, Hunan Provincial Engineering Research Center for Healthy Livestock and Poultry Production, Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, No. 644 Yuanda Road, Furong District, Changsha, 410125, Hunan, China.,University of Chinese Academy of Sciences, Beijing, 100039, China
| | - Kang Yao
- College of Animal Science and Technology, Hunan Agricultural University, Changsha, 410128, China. .,Scientific Observation and Experiment Station of Animal Nutrition and Feed Science in South-Central China, Ministry of Agriculture, Hunan Provincial Engineering Research Center for Healthy Livestock and Poultry Production, Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, No. 644 Yuanda Road, Furong District, Changsha, 410125, Hunan, China.
| | - Fengna Li
- Scientific Observation and Experiment Station of Animal Nutrition and Feed Science in South-Central China, Ministry of Agriculture, Hunan Provincial Engineering Research Center for Healthy Livestock and Poultry Production, Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, No. 644 Yuanda Road, Furong District, Changsha, 410125, Hunan, China
| | - Yongqing Hou
- Hubei Collaborative Innovation Center for Animal Nutrition and Feed Safety, Hubei Key Laboratory of Animal Nutrition and Feed Science, Wuhan Polytechnic University, Wuhan, 430023, China
| | - Guoyao Wu
- Scientific Observation and Experiment Station of Animal Nutrition and Feed Science in South-Central China, Ministry of Agriculture, Hunan Provincial Engineering Research Center for Healthy Livestock and Poultry Production, Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, No. 644 Yuanda Road, Furong District, Changsha, 410125, Hunan, China.,Hubei Collaborative Innovation Center for Animal Nutrition and Feed Safety, Hubei Key Laboratory of Animal Nutrition and Feed Science, Wuhan Polytechnic University, Wuhan, 430023, China.,Department of Animal Science, Texas A&M University, College Station, TX, 77843, USA
| | - Yulong Yin
- College of Animal Science and Technology, Hunan Agricultural University, Changsha, 410128, China. .,Scientific Observation and Experiment Station of Animal Nutrition and Feed Science in South-Central China, Ministry of Agriculture, Hunan Provincial Engineering Research Center for Healthy Livestock and Poultry Production, Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, No. 644 Yuanda Road, Furong District, Changsha, 410125, Hunan, China. .,Hubei Collaborative Innovation Center for Animal Nutrition and Feed Safety, Hubei Key Laboratory of Animal Nutrition and Feed Science, Wuhan Polytechnic University, Wuhan, 430023, China.
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12
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Plas RLC, Degens H, Meijer JP, de Wit GMJ, Philippens IHCHM, Bobbert MF, Jaspers RT. Muscle contractile properties as an explanation of the higher mean power output in marmosets than humans during jumping. ACTA ACUST UNITED AC 2015; 218:2166-73. [PMID: 25987730 DOI: 10.1242/jeb.117655] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2014] [Accepted: 05/08/2015] [Indexed: 11/20/2022]
Abstract
The muscle mass-specific mean power output (PMMS,mean) during push-off in jumping in marmosets (Callithrix jacchus) is more than twice that in humans. In the present study it was tested whether this is attributable to differences in muscle contractile properties. In biopsies of marmoset m. vastus lateralis (VL) and m. gastrocnemius medialis (GM) (N=4), fibre-type distribution was assessed using fluorescent immunohistochemistry. In single fibres from four marmoset and nine human VL biopsies, the force-velocity characteristics were determined. Marmoset VL contained almost exclusively fast muscle fibres (>99.0%), of which 63% were type IIB and 37% were hybrid fibres, fibres containing multiple myosin heavy chains. GM contained 9% type I fibres, 44% type IIB and 47% hybrid muscle fibres. The proportions of fast muscle fibres in marmoset VL and GM were substantially larger than those reported in the corresponding human muscles. The curvature of the force-velocity relationships of marmoset type IIB and hybrid fibres was substantially flatter than that of human type I, IIA, IIX and hybrid fibres, resulting in substantially higher muscle fibre mass-specific peak power (PFMS,peak). Muscle mass-specific peak power output (PMMS,peak) values of marmoset whole VL and GM, estimated from their fibre-type distributions and force-velocity characteristics, were more than twice the estimates for the corresponding human muscles. As the relative difference in estimated PMMS,peak between marmosets and humans is similar to that of PMMS,mean during push-off in jumping, it is likely that the difference in in vivo mechanical output between humans and marmosets is attributable to differences in muscle contractile properties.
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Affiliation(s)
- Rogier L C Plas
- MOVE Research Institute Amsterdam, Faculty of Human Movement Sciences, VU University Amsterdam, Van der Boechorstraat 9, Amsterdam NL-1081 BT, The Netherlands School of Healthcare Science, Cognitive Motor Function Research Group, School of Healthcare Science, Manchester Metropolitan University, Chester Street, Manchester M1 5GD, UK
| | - Hans Degens
- School of Healthcare Science, Cognitive Motor Function Research Group, School of Healthcare Science, Manchester Metropolitan University, Chester Street, Manchester M1 5GD, UK
| | - J Peter Meijer
- MOVE Research Institute Amsterdam, Faculty of Human Movement Sciences, VU University Amsterdam, Van der Boechorstraat 9, Amsterdam NL-1081 BT, The Netherlands School of Healthcare Science, Cognitive Motor Function Research Group, School of Healthcare Science, Manchester Metropolitan University, Chester Street, Manchester M1 5GD, UK
| | - Gerard M J de Wit
- MOVE Research Institute Amsterdam, Faculty of Human Movement Sciences, VU University Amsterdam, Van der Boechorstraat 9, Amsterdam NL-1081 BT, The Netherlands
| | - Ingrid H C H M Philippens
- Department of Immunobiology, Division Neuropathology, Biomedical Primate Research Centre, Rijswijk, The Netherlands
| | - Maarten F Bobbert
- MOVE Research Institute Amsterdam, Faculty of Human Movement Sciences, VU University Amsterdam, Van der Boechorstraat 9, Amsterdam NL-1081 BT, The Netherlands
| | - Richard T Jaspers
- MOVE Research Institute Amsterdam, Faculty of Human Movement Sciences, VU University Amsterdam, Van der Boechorstraat 9, Amsterdam NL-1081 BT, The Netherlands
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13
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Takeda I, Takahashi T, Ochi K, Kurashige T, Shinozaki Y, Nakamori M, Arihiro K, Maruyama H, Matsumoto M. Fiber type-specific expression of low-density lipoprotein receptor-related protein 6 in human skeletal muscles. Pathobiology 2014; 81:94-9. [PMID: 24457908 DOI: 10.1159/000357238] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2013] [Accepted: 11/13/2013] [Indexed: 11/19/2022] Open
Abstract
OBJECTIVE Gene expression patterns differ in the two types of skeletal muscle fiber. The Wnt signaling pathway, which includes low-density lipoprotein receptor-related protein 6 (LRP6), has been associated with cell differentiation and glucose metabolism in skeletal muscles. We examined the relationships between muscle fiber types and LRP6 expression. METHODS Adenosine triphosphatase was assayed histochemically, and the levels of expression of LRP6 and myosin were analyzed immunohistochemically, in frozen sections of muscle fiber obtained from 16 muscle biopsy samples. The expression pattern of LRP6 in C2C12 cells was assayed by immunocytochemistry. RESULTS LRP6 was expressed only in type II fibers. Type IIc fibers showed variations in LRP6 expression. Expression of LRP6 was observed at the stage of myoblast differentiation. CONCLUSION Antibody to LRP6 may be useful for identifying type II skeletal muscle fibers. LRP6 may influence glucose metabolism in type II fibers of human skeletal muscles.
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Affiliation(s)
- Ikuko Takeda
- Department of Clinical Neuroscience and Therapeutics, Hiroshima University, Hiroshima, Japan
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14
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Zhang M, Liu YL, Fu CY, Wang J, Chen SY, Yao J, Lai SJ. Expression of MyHC genes, composition of muscle fiber type and their association with intramuscular fat, tenderness in skeletal muscle of Simmental hybrids. Mol Biol Rep 2013; 41:833-40. [PMID: 24374854 DOI: 10.1007/s11033-013-2923-6] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2013] [Accepted: 12/18/2013] [Indexed: 10/25/2022]
Abstract
In adult bovine skeletal muscle, it expressed four isoforms of Myosin heavy chain (MyHC) gene, MyHC-I, MyHC-IIa, MyHC-IIb, and MyHC-IIx that are translated into different structural protein myofibrils, and then further form different types of muscle fiber. In the studies, our objective is to reveal the expression patterns of MyHC genes in longissimus dorsi (Ld), semitendinosus (Se) and soleus (Sol) of Simmental hybrids cattle, and their association with intramuscular fat (IMF) content and meat shearing force (MSF). The muscle tissue of Ld, Se and Sol were collected from 6, 12 and 36-month old Simmental hybrids respectively, then the expression levels of MyHCs were examined by real-time PCR, at the same time, IMF, MSF and muscle type were measured with chemical assessment, shearing force measurer and immunostaining respectively. Our results showed that t Ld, Se, and Sol expressed MyHC-I, MyHC-IIa and MyHC-IIx isoforms but not MyHC-IIb, furthermore MyHC-I, MyHC-IIa and MyHC-IIx had different expression patterns in different skeletal muscle. The expression of MyHC-I in Se and Sol, MyHC-IIa in Ld, Se, and Sol, and MyHC-IIx in Sol was decreased with increasing age. The highest expression of MyHC-I in Ld, and MyHC-IIx in Ld and Se was observed in 12-month-old animals. The percentage of type-IIa fiber approximately occupied 70-80 % among various muscle fiber of Ld, Se and Sol. The percentage of different type fiber was not related to IMF content and MSF, but the expression levels of MyHC-I and MyHC-IIa were negatively related to IMF content (r = -0.724, and -0.681, respectively) and MSF (r = -0.672, and -0.641, respectively). The expression level of MyHC-IIx was also negatively related to MSF (r = -0.655). In conclusion, MyHC gene might be considered as a negative factor in genetic selection of IMF content and MSF.
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Affiliation(s)
- Ming Zhang
- College of Animal Science & Technology, Sichuan Agricultural University, Ya'an, 625014, China,
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15
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A novel intronic single nucleotide polymorphism in the myosin heavy polypeptide 4 gene is responsible for the mini-muscle phenotype characterized by major reduction in hind-limb muscle mass in mice. Genetics 2013; 195:1385-95. [PMID: 24056412 DOI: 10.1534/genetics.113.154476] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Replicated artificial selection for high levels of voluntary wheel running in an outbred strain of mice favored an autosomal recessive allele whose primary phenotypic effect is a 50% reduction in hind-limb muscle mass. Within the High Runner (HR) lines of mice, the numerous pleiotropic effects (e.g., larger hearts, reduced total body mass and fat mass, longer hind-limb bones) of this hypothesized adaptive allele include functional characteristics that facilitate high levels of voluntary wheel running (e.g., doubling of mass-specific muscle aerobic capacity, increased fatigue resistance of isolated muscles, longer hind-limb bones). Previously, we created a backcross population suitable for mapping the responsible locus. We phenotypically characterized the population and mapped the Minimsc locus to a 2.6-Mb interval on MMU11, a region containing ∼100 known or predicted genes. Here, we present a novel strategy to identify the genetic variant causing the mini-muscle phenotype. Using high-density genotyping and whole-genome sequencing of key backcross individuals and HR mice with and without the mini-muscle mutation, from both recent and historical generations of the HR lines, we show that a SNP representing a C-to-T transition located in a 709-bp intron between exons 11 and 12 of the Myosin heavy polypeptide 4 (Myh4) skeletal muscle gene (position 67,244,850 on MMU11; assembly, December 2011, GRCm38/mm10; ENSMUSG00000057003) is responsible for the mini-muscle phenotype, Myh4(Minimsc). Using next-generation sequencing, our approach can be extended to identify causative mutations arising in mouse inbred lines and thus offers a great avenue to overcome one of the most challenging steps in quantitative genetics.
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Smerdu V, Cvetko E. Myosin heavy chain-2b transcripts and isoform are expressed in human laryngeal muscles. Cells Tissues Organs 2013; 198:75-86. [PMID: 23796659 DOI: 10.1159/000351293] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/10/2013] [Indexed: 11/19/2022] Open
Abstract
Three fast myosin heavy chain (MyHC) isoforms, i.e. MyHC-2a, -2x and -2b, are expressed in skeletal muscles of smaller mammals. In contrast, only MyHC-2a and -2x have been revealed in humans so far. The expression of MyHC isoforms is known to be wider in the functionally more specialized laryngeal muscles. Though mRNA transcripts of the MyHC-2b gene were found to be expressed in certain human skeletal and laryngeal muscles, the corresponding isoform has not been demonstrated in these muscles. To our knowledge, we are the first to demonstrate not only the expression of MyHC-2b transcripts using an in situ hybridization technique but also the corresponding protein, i.e. the MyHC-2b isoform, in some human laryngeal muscles by immunohistochemistry but not by polyacrylamide gel electrophoresis. Using a set of antibodies specific to MyHC isoforms, we demonstrated that MyHC-2b was always co-expressed with the major MyHC isoforms, not only with the fast ones (MyHC-2a and -2x) but with the slow isoform (MyHC-1) as well.
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Affiliation(s)
- Vika Smerdu
- Institute of Anatomy, Faculty of Medicine, University of Ljubljana, SI-1000 Ljubljana, Slovenia.
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17
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Nakamura S, Kawai N, Ohnuki Y, Saeki Y, Korfage JAM, Langenbach GEJ, Kitayama T, Watanabe M, Sano R, Tanne K, Tanaka E. Changes in activity and structure of jaw muscles in Parkinson's disease model rats. J Oral Rehabil 2013; 40:205-13. [DOI: 10.1111/joor.12030] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/18/2012] [Indexed: 11/29/2022]
Affiliation(s)
- S. Nakamura
- Department of Orthodontics and Dentofacial Orthopedics; The University of Tokushima Graduate School of Oral Sciences; Tokushima Japan
| | - N. Kawai
- Department of Orthodontics and Dentofacial Orthopedics; The University of Tokushima Graduate School of Oral Sciences; Tokushima Japan
| | - Y. Ohnuki
- Department of Physiology; Tsurumi University School of Dental Medicine; Yokohama Japan
| | - Y. Saeki
- Department of Physiology; Tsurumi University School of Dental Medicine; Yokohama Japan
| | - J. A. M. Korfage
- Department of Oral Cell Biology and Functional Anatomy; Academic Centre for Dentistry Amsterdam (ACTA); Research Institute MOVE; University of Amsterdam and VU University Amsterdam; Amsterdam The Netherlands
| | - G. E. J. Langenbach
- Department of Oral Cell Biology and Functional Anatomy; Academic Centre for Dentistry Amsterdam (ACTA); Research Institute MOVE; University of Amsterdam and VU University Amsterdam; Amsterdam The Netherlands
| | - T. Kitayama
- Department of Dental Pharmacology; Hiroshima University Graduate School of Biomedical Sciences; Hiroshima Japan
| | - M. Watanabe
- Department of Oral Biology; Hiroshima University Graduate School of Biomedical Sciences; Hiroshima Japan
| | - R. Sano
- Department of Orthodontics and Craniofacial Developmental Biology; Hiroshima University Graduate School of Biomedical Sciences; Hiroshima Japan
| | - K. Tanne
- Department of Orthodontics and Craniofacial Developmental Biology; Hiroshima University Graduate School of Biomedical Sciences; Hiroshima Japan
| | - E. Tanaka
- Department of Orthodontics and Dentofacial Orthopedics; The University of Tokushima Graduate School of Oral Sciences; Tokushima Japan
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Tajsharghi H, Oldfors A. Myosinopathies: pathology and mechanisms. Acta Neuropathol 2013; 125:3-18. [PMID: 22918376 PMCID: PMC3535372 DOI: 10.1007/s00401-012-1024-2] [Citation(s) in RCA: 129] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2012] [Revised: 06/27/2012] [Accepted: 07/19/2012] [Indexed: 11/24/2022]
Abstract
The myosin heavy chain (MyHC) is the molecular motor of muscle and forms the backbone of the sarcomere thick filaments. Different MyHC isoforms are of importance for the physiological properties of different muscle fiber types. Hereditary myosin myopathies have emerged as an important group of diseases with variable clinical and morphological expression depending on the mutated isoform and type and location of the mutation. Dominant mutations in developmental MyHC isoform genes (MYH3 and MYH8) are associated with distal arthrogryposis syndromes. Dominant or recessive mutations affecting the type IIa MyHC (MYH2) are associated with early-onset myopathies with variable muscle weakness and ophthalmoplegia as a consistent finding. Myopathies with scapuloperoneal, distal or limb-girdle muscle weakness including entities, such as myosin storage myopathy and Laing distal myopathy are the result of usually dominant mutations in the gene for slow/β cardiac MyHC (MYH7). Protein aggregation is part of the features in some of these myopathies. In myosin storage myopathy protein aggregates are formed by accumulation of myosin beneath the sarcolemma and between myofibrils. In vitro studies on the effects of different mutations associated with myosin storage myopathy and Laing distal myopathy indicate altered biochemical and biophysical properties of the light meromyosin, which is essential for thick filament assembly. Protein aggregates in the form of tubulofilamentous inclusions in association with vacuolated muscle fibers are present at late stage of dominant myosin IIa myopathy and sometimes in Laing distal myopathy. These protein aggregates exhibit features indicating defective degradation of misfolded proteins. In addition to protein aggregation and muscle fiber degeneration some of the myosin mutations cause functional impairment of the molecular motor adding to the pathogenesis of myosinopathies.
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Affiliation(s)
- Homa Tajsharghi
- Department of Pathology, Institute of Biomedicine, University of Gothenburg, Sahlgrenska University Hospital, 413 45 Gothenburg, Sweden
| | - Anders Oldfors
- Department of Pathology, Institute of Biomedicine, University of Gothenburg, Sahlgrenska University Hospital, 413 45 Gothenburg, Sweden
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Park KA, Lim J, Sohn S, Oh SY. Myosin heavy chain isoform expression in human extraocular muscles: longitudinal variation and patterns of expression in global and orbital layers. Muscle Nerve 2012; 45:713-20. [PMID: 22499099 DOI: 10.1002/mus.23240] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
INTRODUCTION We investigated the distribution of myosin heavy chain (MyHC) isoforms along the length of the global and orbital layers of human extraocular muscles (EOMs). METHODS Whole muscle tissue extracts of human EOMs were cross-sectioned consecutively and separated into orbital and global layers. The extracts from these layers were subjected to electrophoretic analysis, followed by quantification with scanning densitometry. RESULTS MyHC isoforms displayed different distributions along the lengths of EOMs. In the orbital and global layers of all EOMs except for the superior oblique muscle, MyHCeom was enriched in the central regions. MyHCIIa and MyHCI were most abundant in the proximal and distal ends. CONCLUSIONS A variation in MyHC isoform expression was apparent along the lengths of human EOMs. These results provide a basis for understanding the molecular mechanisms underlying the functional diversity of EOMs.
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Affiliation(s)
- Kyung-Ah Park
- Department of Ophthalmology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul 135-710, South Korea
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20
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Pae EK. Response of masticatory muscles to passive stretch stimulus - from perspectives of functional appliances. Korean J Orthod 2012; 42:64-72. [PMID: 23112934 PMCID: PMC3481972 DOI: 10.4041/kjod.2012.42.2.64] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2011] [Revised: 09/21/2011] [Accepted: 11/08/2011] [Indexed: 11/24/2022] Open
Abstract
Objective The aims of this study were to examine whether a passive stretch stimulus by means of a functional appliance induces changes in the fiber composition of masticatory muscles and whether these changes are similar to the changes in stretched limb muscle fibers by using RT-PCR, western blot, and immunohistochemical assays. Methods Five male New Zealand White rabbits were fitted with a prefabricated inclined plane on the maxillary central incisors to force the mandible forward (- 2 mm) and downward (- 4 mm). Further, 1 hind limb was extended and constrained with a cast so that the extensor digitorum longus (EDL) was stretched when the animal used the limb. The animals were sacrificed after 1 week and the masseter, lateral pterygoid, and EDL were processed and compared with those from control animals (n = 3). Results The stretched EDL had a significantly higher percentage of slow fibers, whereas the stretched masticatory muscles did not show changes in the composition of the major contractile proteins after 7 days. Conclusions The transition of fiber phenotypes in response to a stretch stimulus may take longer in the masticatory muscles than in the limb muscles.
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Affiliation(s)
- Eung-Kwon Pae
- Department of Orthodontics and Pediatric Dentistry, University of Maryland, School of Dentistry, Baltimore, MD, USA
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Kurapati R, McKenna C, Lindqvist J, Williams D, Simon M, LeProust E, Baker J, Cheeseman M, Carroll N, Denny P, Laval S, Lochmüller H, Ochala J, Blanco G. Myofibrillar myopathy caused by a mutation in the motor domain of mouse MyHC IIb. Hum Mol Genet 2011; 21:1706-24. [PMID: 22199023 DOI: 10.1093/hmg/ddr605] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Ariel is a mouse mutant that suffers from skeletal muscle myofibrillar degeneration due to the rapid accumulation of large intracellular protein aggregates. This fulminant disease is caused by an ENU-induced recessive mutation resulting in an L342Q change within the motor domain of the skeletal muscle myosin protein MYH4 (MyHC IIb). Although normal at birth, homozygous mice develop hindlimb paralysis from Day 13, consistent with the timing of the switch from developmental to adult myosin isoforms in mice. The mutated myosin (MYH4(L342Q)) is an aggregate-prone protein. Notwithstanding the speed of the process, biochemical analysis of purified aggregates showed the presence of proteins typically found in human myofibrillar myopathies, suggesting that the genesis of ariel aggregates follows a pathogenic pathway shared with other conformational protein diseases of skeletal muscle. In contrast, heterozygous mice are overtly and histologically indistinguishable from control mice. MYH4(L342Q) is present in muscles from heterozygous mice at only 7% of the levels of the wild-type protein, resulting in a small but significant increase in force production in isolated single fibres and indicating that elimination of the mutant protein in heterozygotes prevents the pathological changes observed in homozygotes. Recapitulation of the L342Q change in the functional equivalent of mouse MYH4 in human muscles, MYH1, results in a more aggregate-prone protein.
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Abstract
Mammalian skeletal muscle comprises different fiber types, whose identity is first established during embryonic development by intrinsic myogenic control mechanisms and is later modulated by neural and hormonal factors. The relative proportion of the different fiber types varies strikingly between species, and in humans shows significant variability between individuals. Myosin heavy chain isoforms, whose complete inventory and expression pattern are now available, provide a useful marker for fiber types, both for the four major forms present in trunk and limb muscles and the minor forms present in head and neck muscles. However, muscle fiber diversity involves all functional muscle cell compartments, including membrane excitation, excitation-contraction coupling, contractile machinery, cytoskeleton scaffold, and energy supply systems. Variations within each compartment are limited by the need of matching fiber type properties between different compartments. Nerve activity is a major control mechanism of the fiber type profile, and multiple signaling pathways are implicated in activity-dependent changes of muscle fibers. The characterization of these pathways is raising increasing interest in clinical medicine, given the potentially beneficial effects of muscle fiber type switching in the prevention and treatment of metabolic diseases.
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Affiliation(s)
- Stefano Schiaffino
- Venetian Institute of Molecular Medicine, Department of Biomedical Sciences, University of Padova, Consiglio Nazionale delle Ricerche Institute of Neurosciences, and Department of Human Anatomy and Physiology, University of Padova, Padova, Italy
| | - Carlo Reggiani
- Venetian Institute of Molecular Medicine, Department of Biomedical Sciences, University of Padova, Consiglio Nazionale delle Ricerche Institute of Neurosciences, and Department of Human Anatomy and Physiology, University of Padova, Padova, Italy
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IIb or not IIb? Regulation of myosin heavy chain gene expression in mice and men. Skelet Muscle 2011; 1:5. [PMID: 21798083 PMCID: PMC3143903 DOI: 10.1186/2044-5040-1-5] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2010] [Accepted: 02/01/2011] [Indexed: 11/18/2022] Open
Abstract
Background While the myosin heavy chain IIb isoform (MyHC-IIb) is the predominant motor protein in most skeletal muscles of rats and mice, the messenger RNA (mRNA) for this isoform is only expressed in a very small subset of specialized muscles in adult large mammals, including humans. Results We identify the DNA sequences limiting MyHC-IIb expression in humans and explore the activation of this gene in human skeletal muscle. We demonstrate that the transcriptional activity of ~1.0 kb of the human MyHC-IIb promoter is greatly reduced compared to that of the corresponding mouse sequence in both mouse and human myotubes in vitro and show that nucleotide differences that eliminate binding sites for myocyte enhancer factor 2 (MEF2) and serum response factor (SRF) account for this difference. Despite these differences, we show that MyHC-IIb mRNA is expressed in fetal human muscle cells and that MyHC-IIb mRNA is significantly up-regulated in the skeletal muscle of Duchene muscular dystrophy patients. Conclusions These data identify the genetic basis for a key phenotypic difference between the muscles of large and small mammals, and demonstrate that mRNA expression of the MyHC-IIb gene can be re-activated in human limb muscle undergoing profound degeneration/regeneration.
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Yan Z, Okutsu M, Akhtar YN, Lira VA. Regulation of exercise-induced fiber type transformation, mitochondrial biogenesis, and angiogenesis in skeletal muscle. J Appl Physiol (1985) 2010; 110:264-74. [PMID: 21030673 DOI: 10.1152/japplphysiol.00993.2010] [Citation(s) in RCA: 215] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Skeletal muscle exhibits superb plasticity in response to changes in functional demands. Chronic increases of skeletal muscle contractile activity, such as endurance exercise, lead to a variety of physiological and biochemical adaptations in skeletal muscle, including mitochondrial biogenesis, angiogenesis, and fiber type transformation. These adaptive changes are the basis for the improvement of physical performance and other health benefits. This review focuses on recent findings in genetically engineered animal models designed to elucidate the mechanisms and functions of various signal transduction pathways and gene expression programs in exercise-induced skeletal muscle adaptations.
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Affiliation(s)
- Zhen Yan
- Department of Medicine, University of Virginia, Charlottesville, Virginia, USA.
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25
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Harzer W, Maricic N, Gedrange T, Lewis MP, Hunt NP. Molecular Diagnosis in Orthodontics, Facial Orthopedics, and Orthognathic Surgery: Implications for Treatment Progress and Relapse. Semin Orthod 2010. [DOI: 10.1053/j.sodo.2010.02.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Differences in aberrant expression and splicing of sarcomeric proteins in the myotonic dystrophies DM1 and DM2. Acta Neuropathol 2010; 119:465-79. [PMID: 20066428 PMCID: PMC4199327 DOI: 10.1007/s00401-010-0637-6] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2009] [Revised: 12/31/2009] [Accepted: 01/01/2010] [Indexed: 02/03/2023]
Abstract
Aberrant transcription and mRNA processing of multiple genes due to RNA-mediated toxic gain-of-function has been suggested to cause the complex phenotype in myotonic dystrophies type 1 and 2 (DM1 and DM2). However, the molecular basis of muscle weakness and wasting and the different pattern of muscle involvement in DM1 and DM2 are not well understood. We have analyzed the mRNA expression of genes encoding muscle-specific proteins and transcription factors by microarray profiling and studied selected genes for abnormal splicing. A subset of the abnormally regulated genes was further analyzed at the protein level. TNNT3 and LDB3 showed abnormal splicing with significant differences in proportions between DM2 and DM1. The differential abnormal splicing patterns for TNNT3 and LDB3 appeared more pronounced in DM2 relative to DM1 and are among the first molecular differences reported between the two diseases. In addition to these specific differences, the majority of the analyzed genes showed an overall increased expression at the mRNA level. In particular, there was a more global abnormality of all different myosin isoforms in both DM1 and DM2 with increased transcript levels and a differential pattern of protein expression. Atrophic fibers in DM2 patients expressed only the fast myosin isoform, while in DM1 patients they co-expressed fast and slow isoforms. However, there was no increase of total myosin protein levels, suggesting that aberrant protein translation and/or turnover may also be involved.
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Burghardt TP, Neff KL, Wieben ED, Ajtai K. Myosin individualized: single nucleotide polymorphisms in energy transduction. BMC Genomics 2010; 11:172. [PMID: 20226094 PMCID: PMC2848645 DOI: 10.1186/1471-2164-11-172] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2009] [Accepted: 03/15/2010] [Indexed: 11/28/2022] Open
Abstract
BACKGROUND Myosin performs ATP free energy transduction into mechanical work in the motor domain of the myosin heavy chain (MHC). Energy transduction is the definitive systemic feature of the myosin motor performed by coordinating in a time ordered sequence: ATP hydrolysis at the active site, actin affinity modulation at the actin binding site, and the lever-arm rotation of the power stroke. These functions are carried out by several conserved sub-domains within the motor domain. Single nucleotide polymorphisms (SNPs) affect the MHC sequence of many isoforms expressed in striated muscle, smooth muscle, and non-muscle tissue. The purpose of this work is to provide a rationale for using SNPs as a functional genomics tool to investigate structurefunction relationships in myosin. In particular, to discover SNP distribution over the conserved sub-domains and surmise what it implies about sub-domain stability and criticality in the energy transduction mechanism. RESULTS An automated routine identifying human nonsynonymous SNP amino acid missense substitutions for any MHC gene mined the NCBI SNP data base. The routine tested 22 MHC genes coding muscle and non-muscle isoforms and identified 89 missense mutation positions in the motor domain with 10 already implicated in heart disease and another 8 lacking sequence homology with a skeletal MHC isoform for which a crystallographic model is available. The remaining 71 SNP substitutions were found to be distributed over MHC with 22 falling outside identified functional sub-domains and 49 in or very near to myosin sub-domains assigned specific crucial functions in energy transduction. The latter includes the active site, the actin binding site, the rigid lever-arm, and regions facilitating their communication. Most MHC isoforms contained SNPs somewhere in the motor domain. CONCLUSIONS Several functional-crucial sub-domains are infiltrated by a large number of SNP substitution sites suggesting these domains are engineered by evolution to be too-robust to be disturbed by otherwise intrusive sequence changes. Two functional sub-domains are SNP-free or relatively SNP-deficient but contain many disease implicated mutants. These sub-domains are apparently highly sensitive to any missense substitution suggesting they have failed to evolve a robust sequence paradigm for performing their function.
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Affiliation(s)
- Thomas P Burghardt
- Department of Biochemistry and Molecular Biology, Mayo Clinic Rochester, 200 First Street SW, Rochester, MN 55905, USA
- Department of Physiology and Biomedical Engineering, Mayo Clinic Rochester, 200 First Street SW, Rochester, MN 55905, USA
| | - Kevin L Neff
- Department of Biochemistry and Molecular Biology, Mayo Clinic Rochester, 200 First Street SW, Rochester, MN 55905, USA
| | - Eric D Wieben
- Department of Biochemistry and Molecular Biology, Mayo Clinic Rochester, 200 First Street SW, Rochester, MN 55905, USA
| | - Katalin Ajtai
- Department of Biochemistry and Molecular Biology, Mayo Clinic Rochester, 200 First Street SW, Rochester, MN 55905, USA
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Mascarello F, Patruno M, Toniolo L, Reggiani C, Maccatrozzo L. Phenotypic expression of 2b myosin heavy chain isoform: a comparative study among species and different muscles. Vet Res Commun 2009; 33 Suppl 1:105-7. [PMID: 19578947 DOI: 10.1007/s11259-009-9301-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- F Mascarello
- Dipartimento di Scienze Sperimentali Veterinarie, Università degli Studi di Padova, Padova, Italy.
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Stirn Kranjc B, Smerdu V, Erzen I. Histochemical and immunohistochemical profile of human and rat ocular medial rectus muscles. Graefes Arch Clin Exp Ophthalmol 2009; 247:1505-15. [PMID: 19609551 PMCID: PMC2758108 DOI: 10.1007/s00417-009-1128-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2009] [Accepted: 06/15/2009] [Indexed: 11/26/2022] Open
Abstract
PURPOSE To compare the organization of human and rat ocular medial recti muscles (MR). METHODS The cryosections of human and rat MR were processed for myofibrillar ATPase (mATPase), succinate dehydrogenase and glycerol-3-phosphate dehydrogenase. To reveal myosin heavy chain (MyHC) isoforms, specific monoclonal antibodies against MyHC-1/beta- slow, alpha-cardiac (-alpha), -2a, -2x, -2b, -extraocular (eom), -embryonic (-emb) and -neonatal (-neo) were applied. The MyHC gene expression was studied by in situ hybridization in human muscle. RESULTS The muscle fibers were arranged in two distinct layers in both species. In the orbital layer most fibers were highly oxidative and expressed fast MyHC isoforms, whereas slow and oxidative fibers expressed MyHC-1 and -alpha, some of them also MyHC-2a, -2x, -eom, very rarely -emb, and -neo. In the global layer, slow fibers with very low oxidative and glycolytic activity and three types of fast fibers, glycolytic, oxidative and oxidative-glycolytic, could be distinguished. The slow medium-sized fibers with mATPase activity stable at pH 4.4 expressed mostly MyHC-1 and -alpha in rat, while in humans they co-expressed MyHC-1 with -2b, -2x, -eom, and -neo. In both species, the fast fibers showed variable mATPase activity after preincubation at pH 9.4, and co-expressed various combinations of MyHC-2b, -2x, -2a and -eom but not -emb and -neo. MyHC-2b expressing fibers were larger and glycolytic, while MyHC-2a expressing fibers were smaller and highly oxidative in both species. To our knowledge, the present study is the first that demonstrated the expression of MyHC-2b in any of human skeletal muscles. Though the expression of MyHC genes did not correlate with the immunohistochemical profile of fibers in human MR, the expression of MyHC-2b gene was undoubtedly confirmed. CONCLUSIONS Rat MR represent a good model that can be applied to study human MR in experiment or disease, however certain differences are to be expected due to specific oculomotor demands in humans.
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Affiliation(s)
- Branka Stirn Kranjc
- University Medical Centre, University Eye Hospital Ljubljana, Ljubljana, Slovenia.
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Hemmings KM, Parr T, Daniel ZCTR, Picard B, Buttery PJ, Brameld JM. Examination of myosin heavy chain isoform expression in ovine skeletal muscles. J Anim Sci 2009; 87:3915-22. [PMID: 19684280 DOI: 10.2527/jas.2009-2067] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The contractile and associated metabolic characteristics of muscles are determined by their myosin heavy chain (MHC) isoform expression. In large mammals, the level of MHCIIB expression, which is associated with fast glycolytic-type muscle fibers, has not been fully characterized. In this study, quantitative reverse transcription-PCR and SDS-PAGE methodologies were developed for the analyses of adult ovine MHC isoform expression and used to characterize MHC expression in 3 skeletal muscles [LM, semitendinosus, and supraspinatus) from 66-d-old lambs. Three MHC isoforms (MHCI, MHCIIA, and MHCIIX) were detected at both the protein and messenger RNA levels in all 3 muscles, with greater proportions of type II than type I MHC. The expression of MHCIIB could not be detected at the protein level in any of the muscles and was detectable (in semitendinosus muscle) only at the messenger RNA level by using semiquantitative reverse transcription-PCR, indicating that MHCIIX is the predominant fast glycolytic fiber type in the sheep muscles studied. The methodologies developed are suitable for studying fiber type transformations at the molecular level, as well as allowing analyses of very small samples, including biopsies, when histochemical analysis may not be possible.
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Affiliation(s)
- K M Hemmings
- Division of Nutritional Sciences, School of Biosciences, Sutton Bonington Campus, University of Nottingham, Leicestershire, LE12 5RD, United Kingdom.
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Grünheid T, Langenbach GEJ, Korfage JAM, Zentner A, van Eijden TMGJ. The adaptive response of jaw muscles to varying functional demands. Eur J Orthod 2009; 31:596-612. [PMID: 19656804 DOI: 10.1093/ejo/cjp093] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Jaw muscles are versatile entities that are able to adapt their anatomical characteristics, such as size, cross-sectional area, and fibre properties, to altered functional demands. The dynamic nature of muscle fibres allows them to change their phenotype to optimize the required contractile function while minimizing energy use. Changes in these anatomical parameters are associated with changes in neuromuscular activity as the pattern of muscle activation by the central nervous system plays an important role in the modulation of muscle properties. This review summarizes the adaptive response of jaw muscles to various stimuli or perturbations in the orofacial system and addresses general changes in muscles as they adapt, specific adaptive changes in jaw muscles under various physiologic and pathologic conditions, and their adaptive response to non-surgical and surgical therapeutic interventions. Although the jaw muscles are used concertedly in the masticatory system, their adaptive changes are not always uniform and vary with the nature, intensity, and duration of the stimulus. In general, stretch, increases neuromuscular activity, and resistance training result in hypertrophy, elicits increases in mitochondrial content and cross-sectional area of the fibres, and may change the fibre-type composition of the muscle towards a larger percentage of slow-type fibres. In contrast, changes in the opposite direction occur when neuromuscular activity is reduced, the muscle is immobilized in a shortened position, or paralysed. The broad range of stimuli that affect the properties of jaw muscles might help explain the large variability in the anatomical and physiological characteristics found among individuals, muscles, and muscle portions.
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Affiliation(s)
- Thorsten Grünheid
- Department of General and Specialised Dentistry, Section of Orthodontics, Academic Centre for Dentistry Amsterdam (ACTA), The Netherlands.
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Evidence for expression of IIb myosin heavy chain isoform in some skeletal muscles of Blonde d’Aquitaine bulls. Meat Sci 2009; 82:30-6. [DOI: 10.1016/j.meatsci.2008.11.022] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2008] [Revised: 10/06/2008] [Accepted: 11/28/2008] [Indexed: 11/20/2022]
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Karen P, Stevanec M, Smerdu V, Cvetko E, Kubínová L, Erzen I. Software for muscle fibre type classification and analysis. Eur J Histochem 2009; 53:e11. [PMID: 19683982 PMCID: PMC3167282 DOI: 10.4081/ejh.2009.e11] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/26/2009] [Indexed: 11/23/2022] Open
Abstract
Fibre type determination requires a large series of differently stained muscle sections. The manual identification of individual fibres through the series is tedious and time consuming. This paper presents a software that enables (i) adjusting the position of individual fibres through a series of differently stained sections (image registration) and identification of individual fibres through the series as well as (ii) muscle fibre classification and (iii) quantitative analysis. The data output of the system is the following: numerical and areal proportions of fibre types, fibre type size and optical density (grey level) of the final reaction product in every fibre. The muscle fibre type can be determined stepwise, based on one set of stained sections while further, newly stained sections can be added to the already defined muscle fibre profile. Several advantages of the presented software application in skeletal muscle research are presented. The system is semiquantitative, flexible, and user friendly.
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Affiliation(s)
- P Karen
- Department of Biomathematics, Institute of Physiology, Academy of Sciences of the Czech Republic, v.v.i., Prague, Czech Republic
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Mallinson J, Meissner J, Chang KC. Chapter 2. Calcineurin signaling and the slow oxidative skeletal muscle fiber type. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2009; 277:67-101. [PMID: 19766967 DOI: 10.1016/s1937-6448(09)77002-9] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Calcineurin, also known as protein phosphatase 2B (PP2B), is a calcium-calmodulin-dependent phosphatase. It couples intracellular calcium to dephosphorylate selected substrates resulting in diverse biological consequences depending on cell type. In mammals, calcineurin's functions include neuronal growth, development of cardiac valves and hypertrophy, activation of lymphocytes, and the regulation of ion channels and enzymes. This chapter focuses on the key roles of calcineurin in skeletal muscle differentiation, regeneration, and fiber type conversion to an oxidative state, all of which are crucial to muscle development, metabolism, and functional adaptations. It seeks to integrate the current knowledge of calcineurin signaling in skeletal muscle and its interactions with other prominent regulatory pathways and their signaling intermediates to form a molecular overview that could provide directions for possible future exploitations in human metabolic health.
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Affiliation(s)
- Joanne Mallinson
- School of Veterinary Medicine and Science, University of Nottingham, Sutton Bonington, UK
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Rinaldi C, Haddad F, Bodell PW, Qin AX, Jiang W, Baldwin KM. Intergenic bidirectional promoter and cooperative regulation of the IIx and IIb MHC genes in fast skeletal muscle. Am J Physiol Regul Integr Comp Physiol 2008; 295:R208-18. [PMID: 18434443 DOI: 10.1152/ajpregu.00134.2008] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
This study investigated the dynamic regulation of IIx-IIb MHC genes in the fast white medial gastrocnemius (WMG) muscle in response to intermittent resistance exercise training (RE), a model associated with a rapid shift from IIb to IIx expression (11). We investigated the effect of 4 days of RE on the transcriptional activity across the skeletal MHC gene locus in the WMG in female Sprague-Dawley rats. Our results show that RE resulted in significant shifts from IIb to IIx observed at both the pre-mRNA and mRNA levels. An antisense RNA (xII NAT) was detected in the intergenic (IG) region between IIx and IIb, extending across the entire IIx gene and into its promoter. The expression of the xII NAT was positively correlated with IIb pre-mRNA (R = +0.8), and negatively correlated with IIx pre-mRNA (R = -0.8). Transcription mapping of the IIx-IIb IG region revealed the generation of sense IIb and xII NATs from a single promoter region. This bidirectional promoter is highly conserved among species and contains several regulatory elements that may be implicated in its regulation. These results suggest that the IIx and the IIb genes are physically and functionally linked via the bidirectional promoter. In order for the IIx MHC gene to be regulated, a feedback mechanism from the IG xII NAT is needed. In conclusion, the IG bidirectional promoter generating antisense RNA appears to be essential for the coordinated regulation of the skeletal muscle MHC genes during dynamic phenotype shifts.
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Affiliation(s)
- Chiara Rinaldi
- Physiology and Biophysics Department, University of California Irvine, Irvine, CA, USA
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Horton MJ, Rosen C, Close JM, Sciote JJ. Quantification of myosin heavy chain RNA in human laryngeal muscles: differential expression in the vertical and horizontal posterior cricoarytenoid and thyroarytenoid. Laryngoscope 2008; 118:472-7. [PMID: 18091331 PMCID: PMC3879044 DOI: 10.1097/mlg.0b013e31815c1a93] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND Human laryngeal muscles are composed of fibers that express type I, IIA, and IIX myosin heavy chains (MyHC), but the presence and quantity of atypical myosins such as perinatal, extraocular, IIB, and alpha (cardiac) remain in question. These characteristics have been determined by biochemical or immunohistologic tissue sampling but with no complementary evidence of gene expression at the molecular level. The distribution of myosin, the main motor protein, in relation to structure-function relationships in this specialized muscle group will be important for understanding laryngeal function in both health and disease. OBJECTIVES We determined the quantity of MyHC genes expressed in human posterior cricoarytenoid (PCA) and thyroarytenoid (TA) muscle using real-time quantitative reverse-transcriptase polymerase chain reaction in a large number of samples taken from laryngectomy subjects. The PCA muscle was divided into vertical (V) and horizontal (H) portions for analysis. RESULTS AND CONCLUSIONS No extraocular or IIB myosin gene message is present in PCA or TA, but IIB is expressed in human extraocular muscle. Low but detectable amounts of perinatal and alpha gene message are present in both of the intrinsic laryngeal muscles. In H- and V-PCA, MyHC gene amounts were beta greater than IIA greater than IIX, but amounts of fast myosin RNA were greater in V-PCA. In TA, the order was beta greater than IIX greater than IIA. The profiles of RNA determined here indicate that, in humans, neither PCA nor TA intrinsic laryngeal muscles express unique very fast-contracting MyHCs but instead may rely on differential synthesis and use of beta, IIA, and IIX isoforms to perform their specialized contractile functions.
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Affiliation(s)
- Michael J Horton
- Department of Orthodontics, University of Pittsburgh, Pittsburgh, PA 15261-1032, USA
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Sokoloff AJ, Li H, Burkholder TJ. Limited expression of slow tonic myosin heavy chain in human cranial muscles. Muscle Nerve 2007; 36:183-9. [PMID: 17486578 PMCID: PMC3816747 DOI: 10.1002/mus.20797] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Recent reports of slow tonic myosin heavy chain (MHCst) in human masticatory and laryngeal muscles suggest that MHCst may have a wider distribution in humans than previously thought. Because of the novelty of this finding, we sought to confirm the presence of MHCst in human masticatory and laryngeal muscles by reacting tissue from these muscles and controls from extraocular, intrafusal, cardiac, appendicular, and developmental muscle with antibodies (Abs) ALD-58 and S46, considered highly specific for MHCst. At Ab dilutions producing minimal reaction to muscle fibers positive for MHCI, only extraocular, intrafusal, and fetal tongue tissue reacted with Ab S46 had strong immunoreaction in an appreciable number of muscle fibers. In immunoblots, Ab S46, but not Ab ALD-58, labeled adult extraocular muscles; no other muscles were labeled with either Ab. We conclude that, in humans, Ab S46 has greater specificity for MHCst than does Ab ALD-58. We suggest that reports of MHCst in human masticatory and laryngeal muscles reflect false-positive identification of MHCst due to cross-reactivity of Ab ALD-58 with another MHC isoform.
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Affiliation(s)
- Alan J Sokoloff
- Department of Physiology, Emory University School of Medicine, 615 Michael Street, Atlanta, Georgia 30322, USA.
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Harzer W, Worm M, Gedrange T, Schneider M, Wolf P. Myosin heavy chain mRNA isoforms in masseter muscle before and after orthognathic surgery. ACTA ACUST UNITED AC 2007; 104:486-90. [PMID: 17507262 DOI: 10.1016/j.tripleo.2007.01.017] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2006] [Revised: 12/28/2006] [Accepted: 01/11/2007] [Indexed: 10/23/2022]
Abstract
OBJECTIVES Orthognathic surgery leads to changed jaw position and force vector of mastication to which the muscles must adapt. The aim of the present study was to determine the relative expression of myosin heavy chain (MyHC) messenger RNA (mRNA) isoforms in different types of human masseter muscle fiber under consideration of change in the number of occlusal contacts before and 6 months after surgery. STUDY DESIGN Muscle biopsies were taken from the anterior and posterior parts of both sides in 30 patients with prognathic and retrognathic mandibles. Specific mRNA MyHC analysis was made by real-time polymerase chain reaction to quantify the isoforms I, IIa, and IId/x. RESULTS There was a shift in the relative content from type I (46% before, 37% after) to type IIa (29% before, 42% after). This shift correlates with number of teeth in occlusion. CONCLUSIONS Correlation between isoform shift and number of teeth in occlusion indicates higher mastication force which stabilizes the treatment result.
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Affiliation(s)
- Winfried Harzer
- Department of Orthodontics, School of Dentistry, Medical Faculty, University Clinics Carl Gustav Carus, Technical University, Dresden, Germany.
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Toniolo L, Maccatrozzo L, Patruno M, Pavan E, Caliaro F, Rossi R, Rinaldi C, Canepari M, Reggiani C, Mascarello F. Fiber types in canine muscles: myosin isoform expression and functional characterization. Am J Physiol Cell Physiol 2007; 292:C1915-26. [PMID: 17251320 DOI: 10.1152/ajpcell.00601.2006] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
This study was aimed to achieve a definitive and unambiguous identification of fiber types in canine skeletal muscles and of myosin isoforms that are expressed therein. Correspondence of canine myosin isoforms with orthologs in other species as assessed by base sequence comparison was the basis for primer preparation and for expression analysis with RT-PCR. Expression was confirmed at protein level with histochemistry, immunohistochemistry, and SDS-PAGE combined together and showed that limb and trunk muscles of the dog express myosin heavy chain (MHC) type 1, 2A, and 2X isoforms and the so-called “type 2dog” fibers express the MHC-2X isoform. MHC-2A was found to be the most abundant isoform in the trunk and limb muscle. MHC-2X was expressed in most but not all muscles and more frequently in hybrid 2A-2X fibers than in pure 2X fibers. MHC-2B was restricted to specialized extraocular and laryngeal muscles, although 2B mRNA, but not 2B protein, was occasionally detected in the semimembranosus muscle. Isometric tension (Po) and maximum shortening velocity ( Vo) were measured in single fibers classified on the basis of their MHC isoform composition. Purified myosin isoforms were extracted from single muscle fibers and characterized by the speed ( Vf) of actin filament sliding on myosin in an in vitro motility assay. A close proportionality between Vo and Vf indicated that the diversity in Vo was due to the different myosin isoform composition. Vo increased progressively in the order 1/slow < 2A < 2X < 2B, thus confirming the identification of the myosin isoforms and providing their first functional characterization of canine muscle fibers.
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Affiliation(s)
- Luana Toniolo
- Department of Anatomy and Physiology, University of Padova, Via Marzolo 3, 35131 Padova, Italy
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Sokoloff AJ, Yang B, Li H, Burkholder TJ. Immunohistochemical characterization of slow and fast myosin heavy chain composition of muscle fibres in the styloglossus muscle of the human and macaque (Macaca rhesus). Arch Oral Biol 2007; 52:533-43. [PMID: 17210117 PMCID: PMC1991289 DOI: 10.1016/j.archoralbio.2006.11.012] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2006] [Revised: 10/09/2006] [Accepted: 11/16/2006] [Indexed: 11/23/2022]
Abstract
OBJECTIVE Muscle fibre contractile diversity is thought to be increased by the hybridization of multiple myosin heavy chain (MHC) isoforms in single muscle fibres. Reports of hybrid fibres composed of MHCI and MHCII isoforms in human, but not macaque, tongue muscles, suggest a human adaptation for increased tongue muscle contractile diversity. Here we test whether hybrid fibres composed of MHCI and MHCII are unique to human tongue muscles or are present as well in the macaque. METHODS MHC composition of the macaque and human styloglossus was characterized with antibodies that allowed identification of three muscle fibre phenotypes, a slow phenotype composed of MHCI, a fast phenotype composed of MHCII and a hybrid phenotype composed of MHCI and MHCII. RESULTS The fast phenotype constitutes 68.5% of fibres in the macaque and 43.4% of fibres in the human (P<0.0001). The slow phenotype constitutes 20.2% of fibres in the macaque and 39.3% of fibres in the human (P<0.0001). The hybrid phenotype constitutes 11.2% of fibres in the macaque and 17.3% of fibres in the human (P=0.0002). Macaques and humans do not differ in fiber size (cross-sectional area, diameter). However, measures of fibre size differ by phenotype such that fast>hybrid>slow (P<0.05). CONCLUSION These data demonstrate differences in the relative percent of muscle fibre phenotypes in the macaque and human styloglossus but also demonstrate that all three phenotypes are present in both species. These data suggest a similar range of mechanical properties in styloglossus muscle fibres of the macaque and human.
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Affiliation(s)
- Alan J Sokoloff
- Department of Physiology, Emory University School of Medicine, Atlanta, GA 30322, USA.
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Toniolo L, Maccatrozzo L, Patruno M, Caliaro F, Mascarello F, Reggiani C. Expression of eight distinct MHC isoforms in bovine striated muscles: evidence for MHC-2B presence only in extraocular muscles. ACTA ACUST UNITED AC 2006; 208:4243-53. [PMID: 16272247 DOI: 10.1242/jeb.01904] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
This study aimed to analyse the expression of myosin heavy chain (MHC) isoforms in bovine muscles, with particular attention to the MHC-2B gene. Diaphragm, longissimus dorsi, masseter, several laryngeal muscles and two extraocular muscles (rectus lateralis and retractor bulbi) were sampled in adult male Bos taurus (age 18-24 months, mass 400-500 kg) and analysed by RT-PCR, gel electrophoresis and immunohistochemistry. Transcripts and proteins corresponding to eight MHC isoforms were identified: MHC-alpha and MHC-beta/slow (or MHC-1), two developmental isoforms (MHC-embryonic and MHC-neonatal), three adult fast isoforms (MHC-2A, MHC-2X and MHC-2B) and the extraocular isoform MHC-Eo. All eight MHC isoforms were found to be co-expressed in extrinsic eye muscles, retractor bulbi and rectus lateralis, four (beta/slow, 2A, 2X, neonatal) in laryngeal muscles, three (beta/slow, 2A and 2X) in trunk and limb muscles and two (beta/slow and alpha) in masseter. The expression of MHC-2B and MHC-Eo was restricted to extraocular muscles. Developmental MHC isoforms (neonatal and embryonic) were only found in specialized muscles in the larynx and in the eye. MHC-alpha was only found in extraocular and masseter muscle. Single fibres dissected from masseter, diaphragm and longissimus were classified into five groups (expressing, respectively, beta/slow, alpha, slow and 2A, 2A and 2X) on the basis of MHC isoform electrophoretical separation, and their contractile properties [maximum shortening velocity (v(0)) and isometric tension (P(0))] were determined. v(0) increased progressively from slow to fast 2A and fast 2X, whereas hybrid 1-2A fibres and fibres containing MHC-alpha were intermediate between slow and fast 2A.
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Affiliation(s)
- L Toniolo
- Dipartimento di Anatomia e Fisiologia Umana, Università di Padova, Italy
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Acevedo LM, Rivero JLL. New insights into skeletal muscle fibre types in the dog with particular focus towards hybrid myosin phenotypes. Cell Tissue Res 2005; 323:283-303. [PMID: 16163488 DOI: 10.1007/s00441-005-0057-4] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2005] [Accepted: 07/20/2005] [Indexed: 11/28/2022]
Abstract
Electrophoresis, immunoblots, immunohistochemistry and image analysis methods were applied to characterise canine trunk and appendicular muscle fibres according to their myosin heavy chain (MyHC) composition and to determine, on a fibre-to-fibre basis, the correlation between contractile [MyHC (s), myofibrillar ATPase (mATPase) and sarco(endo)plasmic reticulum Ca(2+)-ATPase (SERCA) isoforms], metabolic [succinate dehydrogenase (SDH) and glycerol-3-phosphate dehydrogenase (GPDH) activities and glycogen and phospholamban (PLB) content] and morphological (cross-sectional area and capillary and nuclear densities) features of individual myofibres. An accurate delineation of MyHC-based fibre types was obtained with the developed immunohistochemical method, which showed high sensitivity and objectivity to delineate hybrid fibres with overwhelming dominance of one MyHC isoform. Phenotypic differences in contractile, metabolic and morphological properties seen between fibre types were related to MyHC content. All canine skeletal muscle fibre types had a relatively high histochemical SDH activity but significant differences existed in the order IIA>I>IIX. Mean GPDH was ranked according to fibre type such that I<IIA<IIX. Type IIA fibres were the smallest, type IIX fibres the largest and type I of intermediate size. Capillary and nuclear density decreased in the order IIA>I>IIX. Hybrid fibres, which represented nearly one third of the whole pool of skeletal muscle fibres analysed, had mean values intermediate between their respective pure phenotypes. Slow fibres expressed the slow SERCA isoform and PLB, whereas type II fibres expressed the fast SERCA isoform. Discrimination of myofibres according to their MyHC content was possible on the basis of their contractile, metabolic and morphological features. These intrafibre interrelationships suggest that myofibres of control dogs exhibit a high degree of co-ordination in their physiological, biochemical and morphological characteristics. This study demonstrates that canine skeletal muscle fibres have been misclassified in numerous previous studies and offers useful baseline data and new prospects for future work on muscle-fibre-typing in canine experimental studies.
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Affiliation(s)
- Luz M Acevedo
- Laboratory of Muscular Biopathology, Department of Comparative Anatomy and Pathological Anatomy, Faculty of Veterinary Sciences, University of Cordoba, 14071 Cordoba, Spain
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Eizema K, van den Burg MMM, de Jonge HW, Dingboom EG, Weijs WA, Everts ME. Myosin Heavy Chain Isoforms in Equine Gluteus Medius Muscle: Comparison of mRNA and Protein Expression Profiles. J Histochem Cytochem 2005; 53:1383-90. [PMID: 15983121 DOI: 10.1369/jhc.4a6609.2005] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The major structural protein in skeletal muscle, myosin heavy chain (MyHC), is primarily transcriptionally controlled. We compared the expression of MyHC isoforms on the mRNA and protein level in biopsies from the m. gluteus medius from adult untrained horses. In transverse sections, the majority of fibers showed qualitatively identical mRNA and protein expression patterns. However, coexpression of 2a and 2d/x MyHCs was substantially more common at the protein than at the mRNA level, suggesting a fine-tuning of these two genes in normal muscle not subjected to any training protocol. Because transverse sections give a limited sampling of mRNA expression in the case of uneven distribution of transcripts in a muscle fiber, we also analyzed longitudinal sections. We present, for the first time, evidence that expression of MyHC mRNA and protein was equal along the length of the fiber. Hence, mRNA expression is not regulated by differential expression of isoforms by separate myonuclei. It is concluded that the number of protein hybrid fibers in equine gluteus medius muscle is controlled by alteration of the transcription pattern uniformly along the fiber, rather than by simultaneous transcription of genes. The differences with the results in muscle of small animals and humans are discussed.
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Affiliation(s)
- Karin Eizema
- Utrecht University, Faculty of Veterinary Medicine, Division of Anatomy and Physiology, PO Box 80.158, NL-3508 TD Utrecht, The Netherlands.
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Graziotti GH, Palencia P, Delhon G, Rivero JLL. Neuromuscular partitioning, architectural design, and myosin fiber types of the M. vastus lateralis of the llama (Lama glama). J Morphol 2005; 262:667-81. [PMID: 15376272 DOI: 10.1002/jmor.10268] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The llama (Lama glama) is one of the few mammals of relatively large body size in which three fast myosin heavy chain isoforms (i.e., IIA, IIX, IIB) are extensively expressed in their locomotory muscles. This study was designed to gain insight into the morphological and functional organization of skeletal musculature in this peculiar animal model. The neuromuscular partitioning, architectural design, and myosin fiber types were systematically studied in the M. vastus lateralis of adult llamas (n = 15). Four nonoverlapping neuromuscular partitions or compartments were identified macroscopically (using a modified Sihler's technique for muscle depigmentation), although they did not conform strictly to the definitions of "neuromuscular compartments." Each neuromuscular partition was innervated by primary branches of the femoral nerve and was arranged within the muscle as paired partitions, two in parallel (deep-superficial compartmentalization) and the other two in-series (proximo-distal compartmentalization). These neuromuscular partitions of the muscle varied in their respective architectural designs (studied after partial digestion with diluted nitric acid) and myosin fiber type characteristics (identified immunohistochemically with specific anti-myosin monoclonal antibodies, then examined by quantitative histochemistry and image analysis). The deep partitions of the muscle had longer fibers, with lower angles of pinnation, and higher percentages of fast-glycolytic fibers than the superficial partitions of the muscle. These differences clearly suggest a division of labor in the whole M. vastus lateralis of llamas, with deep partitions exhibiting features well adapted for dynamic activities in the extension of stifle, whereas superficial portions seem to be related to the antigravitational role of the muscle in preserving the extension of the stifle during standing and stance phase of the stride. This peculiar structural and functional organization of the llama M. vastus lateralis does not confirm the generalized idea that deep muscles or the deepest portions within the same muscles somehow develop postural and/or low-intensity isometric functions. Rather, it suggests a primacy of architecture over intramuscular location in determining fiber type composition and hence division of labor within the muscle. A compartmentalization in the distribution of the three fast-subtype fibers (IIA, IIX, and IIB) also occurred, and this could also be relevant functionally, since these fiber types differed significantly in size (IIA < IIX < IIB), oxidative capacity (IIA > IIX > IIB), and capillarization (IIA = IIX > IIB). Furthermore, a typical spatial pattern in fiber type distribution was encountered in llama muscle (i.e., fiber types were consistently ranked in the order I --> IIA --> IIX --> IIB from the center to the periphery of fascicles), suggesting again peculiar and not well understood functional adaptations in these species.
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Affiliation(s)
- Guillermo H Graziotti
- Department of Anatomy and Histology, Faculty of Veterinary Sciences, University of Buenos Aires, Buenos Aires, Argentina
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Sun YM, Da Costa N, Chang KC. Cluster characterisation and temporal expression of porcine sarcomeric myosin heavy chain genes. J Muscle Res Cell Motil 2004; 24:561-70. [PMID: 14870971 DOI: 10.1023/b:jure.0000009895.03111.b3] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Members of the myosin heavy chain (MyHC) gene family are subjected to temporal regulation of gene switching during development. One strategy to the identification of cis-acting regulatory elements that are involved in temporal or fibre-type specific regulation is to undertake a comparative analysis of the MyHC gene family between the pig, an important target species, and other mammals, like human whose entire genome has been recently sequenced. Towards this end, we report here on the isolation, and characterisation of the porcine cardiac (MyHC slow/beta and alpha) and skeletal MyHC (embryonic, 2a, 2x, 2b and perinatal) gene clusters, and their structural comparisons with mouse and human clusters. The genome organisation of both clusters in the pig, human and mouse is conserved as having the same gene order, similar intergenic distances, and in the same head-to-tail orientation. For a period of pre-natal muscle growth, relative expression of MyHC isoforms, as determined by TaqMan real-time RT-PCR, correlated with the gene order in the skeletal MyHC cluster (embryonic > 2a > 2x > 2b) suggesting the possible presence of DNA elements on the same side as the MyHC embryonic gene that direct temporal regulation.
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Affiliation(s)
- Y M Sun
- School of Biochemistry and Molecular Biology, University of Leeds, Leeds LS2 9JT, UK
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Li ZB, Lehar M, Nakagawa H, Hoh JFY, Flint PW. Differential expression of myosin heavy chain isoforms between abductor and adductor muscles in the human larynx. Otolaryngol Head Neck Surg 2004; 130:217-22. [PMID: 14990919 DOI: 10.1016/j.otohns.2003.09.009] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
OBJECTIVE This study examines the differential expression of myosin heavy chain (MyHC) components in human laryngeal muscle groups. STUDY DESIGN A battery of monospecific monoclonal antibodies in Western blots was used to determine expression of IIX, extraocular-specific (EOM), and IIB MyHCs for the thyroarytenoid (TA), vocalis (VOC), lateral cricoarytenoid (LCA), cricothyroid (CT), and posterior cricoarytenoid (PCA) muscles obtained from fresh cadaver specimens. RESULTS Fast IIX MyHC was only expressed in the TA, VOC, and LCA muscles. Fast IIA and slow MyHCs were expressed in all laryngeal muscles including the CT and PCA. The CT with mixed phonatory and respiratory function and the PCA with respiratory function did not express IIX MyHC. The 2 MyHC isoforms associated with the highest speeds of contraction in rat laryngeal muscle, namely, the EOM MyHC and IIB MyHC, were not detected in human laryngeal muscles. Novel MyHC bands were not detected in SDS-PAGE gels or Western blots using a broad specificity MyHC antibody. CONCLUSION The profile of MyHC expression in human laryngeal muscles differs from that observed in human extraocular and masticator muscles, and other mammalian species. Our data demonstrate that IIX MyHC expression is associated primarily with muscles affecting glottic closure and is absent in CT and PCA. SIGNIFICANCE A higher percentage of IIX MyHC is expected to impart a high speed of shortening to the TA and LCA muscles. The absence of IIX MyHC in muscles with respiratory (PCA) and mixed respiratory/phonatory function (CT) further supports the inference that the physiologic difference between laryngeal muscles is reflected in the molecular composition of contractile protein.
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Affiliation(s)
- Zhao-Bo Li
- Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA.
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Quiroz-Rothe E, Rivero JLL. Coordinated expression of myosin heavy chains, metabolic enzymes, and morphological features of porcine skeletal muscle fiber types. Microsc Res Tech 2004; 65:43-61. [PMID: 15570587 DOI: 10.1002/jemt.20090] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Combined methodologies of electrophoresis, immunoblots, immunohistochemistry, histochemistry, and photometric image analysis were applied to characterize porcine skeletal muscle fibers according to their myosin heavy chain (MyHC) composition, and to determine on a fiber-to-fiber basis the correlation between contractile [MyHC (s), myofibrillar ATPase (mATPase), and sarco(endo)plasmic reticulum Ca(2+)-ATPase (SERCA) isoforms], metabolic [succinate dehydrogenase (SDH), and glycerol-3-phosphate dehydrogenase (GPDH) activities, glycogen, and phospholamban (PLB) contents], and morphological [cross-sectional area (CSA), capillary, and nuclear densities] features of individual myofibers. An accurate delineation of MyHC-based fiber types was obtained with the immunohistochemical method developed. This protocol showed a high sensitivity and objectivity to delineate hybrid fibers with overwhelming dominance of one MyHC isoform. The phenotypic differences in contractile, metabolic, and morphological properties seen between fiber types were related with MyHC content. Slow fibers had the lowest mATPase activity (related to shortening velocity), the highest SDH activity (oxidative capacity), the lowest GPDH activity (glycolytic metabolism), and glycogen content, the smallest CSA, the greatest capillary, and nuclear densities, and expressed slow SERCA isoform and PLB, but not the fast SERCA isoform. The reverse pattern was true for pure IIB fibers, whereas type IIA and IIX fibers had intermediate properties. Hybrid fibers had mean values intermediate in-between their respective pure phenotypes. Discrimination of myofibers according to their MyHC content was possible on the basis of their contractile and non-contractile profiles. These intrafiber interrelationships suggest that myofibers of control pigs exhibit a high degree of co-ordination in their physiological, biochemical, and anatomical features. This study may well be a useful baseline for future work on the pig meat industry and also offers new prospects for muscle fiber typing in porcine experimental studies.
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Affiliation(s)
- Eugenio Quiroz-Rothe
- Laboratory of Muscular Biopathology, Department of Comparative Anatomy and Pathological Anatomy, Faculty of Veterinary Sciences, University of Cordoba, 14071 Cordoba, Spain
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Eizema K, van den Burg M, Kiri A, Dingboom EG, van Oudheusden H, Goldspink G, Weijs WA. Differential expression of equine myosin heavy-chain mRNA and protein isoforms in a limb muscle. J Histochem Cytochem 2003; 51:1207-16. [PMID: 12923246 DOI: 10.1177/002215540305100911] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The horse is one of the few animals kept and bred for its athletic performance and is therefore an interesting model for human sports performance. The regulation of the development of equine locomotion in the first year of life, and the influence of early training on later performance, are largely unknown. The major structural protein in skeletal muscle, myosin heavy-chain (MyHC), is believed to be primarily transcriptionally controlled. To investigate the expression of the MyHC genes at the transcriptional level, we isolated cDNAs encoding the equine MyHC isoforms type 1 (slow), type 2a (fast oxidative), and type 2d/x (fast glycolytic). cDNAs encoding the 2b gene were not identified. The mRNA expression was compared to the protein expression on a fiber-to-fiber basis using in situ hybridization (non-radioactive) and immunohistochemistry. Marked differences were detected between the expression of MyHC transcripts and MyHC protein isoforms in adult equine gluteus medius muscle. Mismatches were primarily due to the presence of hybrid fibers expressing two fast (2ad) MyHC protein isoforms, but only one fast (mainly 2a) MyHC RNA isoform. This discrepancy was most likely not due to differential mRNA expression of myonuclei.
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Affiliation(s)
- Karin Eizema
- Department of Pathobiology, Division of Anatomy, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands.
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da Costa N, McGillivray C, Chang KC. Postnatal myosin heavy chain isoforms in prenatal porcine skeletal muscles: insights into temporal regulation. THE ANATOMICAL RECORD. PART A, DISCOVERIES IN MOLECULAR, CELLULAR, AND EVOLUTIONARY BIOLOGY 2003; 273:731-40. [PMID: 12845709 DOI: 10.1002/ar.a.10083] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Our knowledge of the temporal expression of postnatal (adult) fast myosin heavy chain (MyHC) isoforms (2a, 2x, and 2b) in prenatal muscles is limited. Using the pig as a target species and large-animal model, we report on the qualitative and quantitative expression of the major post- and prenatal MyHC isoforms during gestation, as determined by TaqMan real-time PCR and immunohistochemistry. We found that postnatal fast MyHC mRNAs and proteins were expressed much earlier in the pig (gestation day 35) than was previously reported in small mammals. There was a high degree of coexpression and colocalisation of pre- and postnatal MyHC mRNAs and proteins in prenatal muscles. During a period of prenatal muscle growth (gestation days 35-77), relative expression of MyHC isoforms (embryonic > 2a > 2x > 2b) correlated with the gene order in the skeletal MyHC cluster, which suggests the possible presence of cis-acting elements on the same side as the MyHC embryonic gene associated with temporal regulation.
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Affiliation(s)
- Nuno da Costa
- Veterinary Molecular Medicine Laboratory, Institute of Comparative Medicine, University of Glasgow Veterinary School, Glasgow, Scotland
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Sciote JJ, Horton MJ, Rowlerson AM, Link J. Specialized cranial muscles: how different are they from limb and abdominal muscles? Cells Tissues Organs 2003; 174:73-86. [PMID: 12784043 PMCID: PMC3848039 DOI: 10.1159/000070576] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Mammalian skeletal muscle fibers can be classified into functional types by the heavy chain (MyHC) and light chain (MyLC) isoforms of myosin (the primary motor protein) that they contain. Most human skeletal muscle contains fiber types and myosin isoforms I, IIA and IIX. Some highly specialized muscle fibers in human extraocular and jaw-closing muscles express either novel myosins or unusual combinations of isoforms of unknown functional significance. Extrinsic laryngeal muscles may express the extraocular MyHC isoform for rapid contraction and a tonic MyHC isoform for slow tonic contractions. In jaw-closing muscles, fiber phenotypes and myosin expression have been characterized as highly unusual. The jaw-closing muscles of most carnivores and primates have tissue-specific expression of the type IIM or 'type II masticatory' MyHC. Human jaw-closing muscles, however, do not contain IIM myosin. Rather, they express myosins typical of developing or cardiac muscle in addition to type I, IIA and IIX myosins, and many of their fibers are hybrids, expressing two or more isoforms. Fiber morphology is also unusual in that the type II fibers are mostly of smaller diameter than type I. By combining physiological and biochemical techniques it is possible to determine the maximum velocity of unloaded shortening (V(o)) of an individual skeletal muscle fiber and subsequently determine the type and amount of myosin isoform. When analyzed, some laryngeal fibers shorten at much faster rates than type II fibers from limb and abdominal muscle. Yet some type I fibers in masseter show an opposite trend towards speeds 10-fold slower than type I fibers of limb muscle. These unusual shortening velocities are most probably regulated by MyHC isoforms in laryngeal fibers and by MyLC isoforms in masseter. For the jaw-closing muscles, this finding represents the first case in human muscle of physiological regulation of kinetics by light chains. Together, these results demonstrate that, compared to other skeletal muscles, cranial muscles have a wider repertoire of contractile protein expression and function. Molecular techniques for reverse transcription of mRNA and amplification by polymerase chain reaction have been applied to typing of single fibers isolated from limb muscles, successfully identifying pure type I, IIA and IIX and hybrid type I/IIA and IIA/IIX fibers. This demonstrates the potential for future studies of the regulation of gene expression in jaw-closing and laryngeal muscles, which have such a variety of complex fiber types fitting them for their roles in vivo.
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Affiliation(s)
- James J Sciote
- Department of Orthodontics, School of Dental Medicine, University of Pittsburgh, Pittsburgh, PA 15261, USA.
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