scholarly journals Proportions of Myosin Heavy Chain mRNAs, Protein Isoforms and Fiber Types in the Slow and Fast Skeletal Muscles Are Maintained After Alterations of Thyroid Status in Rats

2015 ◽  
pp. 111-118 ◽  
Author(s):  
T. SOUKUP ◽  
M. DIALLO
Keyword(s):  
Myosin Heavy Chain ◽  
Heavy Chain ◽  
Fiber Type ◽  
Protein Isoforms ◽  
Fiber Types ◽  
Lewis Rats ◽  
Type Composition ◽  
2B Protein ◽  
Slow Myhc ◽  
Fast Myhc

Recently, we have established that slow soleus (SOL) and fast extensor digitorum longus (EDL) muscles of euthyroid (EU) Lewis rats posses the same proportions between their four myosin heavy chain (MyHC) mRNAs, protein isoforms and fiber types as determined by real time RT-PCR, SDS-PAGE and 2-D stereological fiber type analysis, respectively. In the present paper we investigated if these proportions are maintained in adult Lewis rats with hyperthyroid (HT) and hypothyroid (HY) status. Although HT and HY states change MyHC isoform expression, results from all three methods showed that proportion between MyHC mRNA-1, ‑2a, -2x/d, -2b, protein isoforms MyHC-1, -2a, -2x/d, -2b and to lesser extent also fiber types 1, 2A, 2X/D, 2B were preserved in both SOL and EDL muscles. Furthermore, in the SOL muscle mRNA expression of slow MyHC-1 remained up to three orders higher compared to fast MyHC transcripts, which explains the predominance of MyHC-1 isoform and fiber type 1 even in HT rats. Although HT status led in the SOL to increased expression of MyHC-2a mRNA, MyHC-2a isoform and 2A fibers, it preserved extremely low expression of MyHC-2x and -2b mRNA and protein isoforms, which explains the absence of pure 2X/D and 2B fibers. HY status, on the other hand, almost completely abolished expression of all three fast MyHC mRNAs, MyHC protein isoforms and fast fiber types in the SOL muscle. Our data present evidence that a correlation between mRNA, protein content and fiber type composition found in EU status is also preserved in HT and HY rats.

scholarly journals Comparison of Myosin Heavy Chain mRNAs, Protein Isoforms and Fiber Type Proportions in the Rat Slow and Fast Muscles

2013 ◽  
pp. 445-453 ◽  
Author(s):  
J. ŽURMANOVÁ ◽  
T. SOUKUP
Keyword(s):  
Myosin Heavy Chain ◽  
Real Time ◽  
Heavy Chain ◽  
Fiber Type ◽  
Protein Isoforms ◽  
Fiber Types ◽  
Rt Pcr ◽  
Fiber Type Composition ◽  
Type Composition

We studied the expression of myosin heavy chain isoforms at mRNA and protein levels as well as fiber type composition in the fast extensor digitorum longus (EDL) and slow soleus (SOL) twitch muscles of adult inbred Lewis strain rats. Comparison of the results from Real Time RT-PCR, SDS-PAGE and fiber type analysis showed corresponding proportions of MyHC transcripts (MyHC-1, -2a, -2x/d, -2b), protein isoforms (MyHC-1, -2a, -2x/d, -2b) and fiber types (type 1, 2A, 2X/D, 2B) in both muscles. Furthermore, we found that slow MyHC-1 mRNA expression in the SOL was up to three orders higher than that of fast MyHC transcripts. This finding can explain the predominance of MyHC-1 isoform and fiber type 1 and the absence of pure 2X/D and 2B fibers in the SOL muscle. Based on our data presenting quantitative evidence of corresponding proportions between mRNA level, protein content and fiber type composition, we suggest that the Real Time RT-PCR technique can be used as a routine method for analysis of muscle composition changes and could be advantageous for the analysis of scant biological samples such as muscle biopsies in humans.

Enzymatic plasticity of medial gastrocnemius fibers in the adult chronic spinal cat

1990 ◽  
Vol 259 (3) ◽  
pp. C507-C514 ◽  
Author(s):  
B. Jiang ◽  
R. R. Roy ◽  
V. R. Edgerton
Keyword(s):  
Myosin Heavy Chain ◽  
Heavy Chain ◽  
Fiber Type ◽  
Motor Units ◽  
Glycolytic Enzyme ◽  
Medial Gastrocnemius ◽  
Fiber Types ◽  
Cross Sectional ◽  
Fast Myosin ◽  
Weight Support

The metabolic plasticity of single fibers in adult cat medial gastrocnemius (MG) 6 mo after complete spinal cord transection (Sp) at T12-T13 was studied. Some Sp cats were trained to weight support (Sp-WS) 30 min/day beginning 1 mo posttransection. Cross-sectional area, succinate dehydrogenase (SDH), alpha-glycerophosphate dehydrogenase (GPD), and myofibrillar adenosinetriphosphatase (ATPase) activities were determined in fibers identified in frozen serial sections. Fibers were categorized as light or dark based on myosin ATPase staining, alkaline preincubation. The percentage of dark ATPase fibers was higher in Sp and Sp-WS (approximately 85%) than in control (approximately 60%). All dark ATPase fibers reacted positively to a fast myosin heavy chain monoclonal antibody. In both spinal groups, a higher percentage of dark ATPase fibers reacted to both fast and slow myosin heavy chain antibodies than in controls. Neither Sp nor Sp-WS cats showed fiber atrophy. Compared with control, SDH activity was decreased in both fiber types of Sp cats. Daily weight-support training ameliorated this adaptation. There were no differences among the three groups in mean GPD and ATPase activities for either fiber type. There was a slight tendency, however, for spinal cats to have higher GPD and ATPase activities (independent of type) than control, probably reflecting the larger proportion of dark ATPase fibers in these cats. These observations indicate that 6 mo after spinalization in adult cats, some of the fibers of a fast muscle became "faster" and developed oxidative and glycolytic enzyme profiles that normally are exhibited in fast fatigable motor units.(ABSTRACT TRUNCATED AT 250 WORDS)

Myogenic specification in somites: induction by axial structures

Development ◽  
1994 ◽  
Vol 120 (6) ◽  
pp. 1443-1452 ◽  
Author(s):  
N. Buffinger ◽  
F.E. Stockdale
Keyword(s):  
Monoclonal Antibodies ◽  
Chick Embryo ◽  
Myosin Heavy Chain ◽  
Neural Tube ◽  
Heavy Chain ◽  
Muscle Fibers ◽  
Fiber Types ◽  
Early Chick Embryo ◽  
Explant Cultures ◽  
Fast Myhc

Specification of the myogenic phenotype in somites was examined in the early chick embryo using organotypic explant cultures stained with monoclonal antibodies to myosin heavy chain. It was found that myogenic specification (formation of muscle fibers in explants of somites or segmental plates cultured alone) does not occur until Hamburger and Hamilton stage 11 (12-14 somites). At this stage, only the somites in the rostral half of the embryo are myogenically specified. By Hamburger and Hamilton stage 12 (15-17 somites), the three most caudal somites were not specified to be myogenic while most or all of the more rostral somites are specified to myogenesis. Somites from older embryos (stage 13–15, 18–26 somites) showed the same pattern of myogenic specification--all but the three most caudal somites were specified. We investigated the effects of the axial structures, the notochord and neural tube, on myogenic specification. Both the notochord and neural tube were able to induce myogenesis in unspecified somites. In contrast, the neural tube, but not the notochord, was able to induce myogenesis in explants of segmental plate, a structure which is not myogenic when cultured alone. When explants of specified somites were stained with antibodies to slow or fast MyHC, it was found that myofiber diversity (fast and fast slow fibers) was established very early in development (as early as Hamburger and Hamilton stage 11). We also found fiber diversity in explants of unspecified somites (the three most caudal somites from stage 11 to 15) when they were recombined with notochord or neural tube. We conclude that myogenic specification in the embryo results in diverse fiber types and is an inductive process which is mediated by factors produced by the neural tube and notochord.

Enhancement of hybrid-fiber types in rat soleus muscle after clenbuterol administration during hindlimb unloading

2004 ◽  
Vol 82 (5) ◽  
pp. 311-318 ◽  
Author(s):  
F Picquet ◽  
L De-Doncker ◽  
M Falempin
Keyword(s):  
Myosin Heavy Chain ◽  
Heavy Chain ◽  
Fiber Type ◽  
Myosin Heavy Chain Isoforms ◽  
Hindlimb Unloading ◽  
Fiber Types ◽  
Myosin Isoforms ◽  
Fast Myosin ◽  
Contractile Parameters ◽  
Fast Myosin Heavy Chain

Our objective was to determine the effects of a clenbuterol (CB) treatment orally administered (2 mg per kg) to rats submitted to 14 days of hindlimb unloading (HU). The morphological and the contractile properties as well as the myosin heavy chain isoforms contained in each fiber type were determined in whole soleus muscles. As classically described after HU, a decrease in muscle wet weight and in body mass associated with a loss of muscular force, an evolution of the contractile parameters towards those of a fast muscle type, and the emergence of fast myosin heavy chain isoforms were observed. The CB treatment in the HU rats helped reduce the decrease in 1) muscle and body weights, 2) force and 3) the proportion of slow fibers, without preventing the emergence of fast myosin isoforms. Clenbuterol induced a complex remodelling of the muscle typing promoting the combination of both slow and fast myosin isoforms within one fiber. To conclude, our data demonstrate that CB administration partially counteracts the effects produced by HU, and they allow us to anticipate advances in the treatment of muscular atrophy.Key words: β2 agonist, clenbuterol, soleus, contractile parameters, myosin, immunohistochemistry, simulated microgravity, countermeasure.

scholarly journals Myosin heavy-chain isoforms in the flight and leg muscles of hummingbirds and zebra finches

2014 ◽  
Vol 306 (11) ◽  
pp. R845-R851 ◽  
Author(s):  
Brandy P. Velten ◽  
Kenneth C. Welch
Keyword(s):  
Myosin Heavy Chain ◽  
Heavy Chain ◽  
Fiber Type ◽  
Myosin Heavy Chain Isoforms ◽  
Contractile Properties ◽  
Morphological Properties ◽  
Fiber Types ◽  
Zebra Finches ◽  
Leg Muscles ◽  
Flight Muscles

Myosin heavy chain (MHC) isoform complement is intimately related to a muscle's contractile properties, yet relatively little is known about avian MHC isoforms or how they may vary with fiber type and/or the contractile properties of a muscle. The rapid shortening of muscles necessary to power flight at the high wingbeat frequencies of ruby-throated hummingbirds and zebra finches (25–60 Hz), along with the varied morphology and use of the hummingbird hindlimb, provides a unique opportunity to understand how contractile and morphological properties of avian muscle may be reflected in MHC expression. Isoforms of the hummingbird and zebra finch flight and hindlimb muscles were electrophoretically separated and compared with those of other avian species representing different contractile properties and fiber types. The flight muscles of the study species operate at drastically different contraction rates and are composed of different histochemically defined fiber types, yet each exhibited the same, single MHC isoform corresponding to the chicken adult fast isoform. Thus, despite quantitative differences in the contractile demands of flight muscles across species, this isoform appears necessary for meeting the performance demands of avian powered flight. Variation in flight muscle contractile performance across species may be due to differences in the structural composition of this conserved isoform and/or variation within other mechanically linked proteins. The leg muscles were more varied in their MHC isoform composition across both muscles and species. The disparity in hindlimb MHC expression between hummingbirds and the other species highlights previously observed differences in fiber type composition and thrust production during take-off.

Early changes in muscle fiber size and gene expression in response to spinal cord transection and exercise

1998 ◽  
Vol 275 (4) ◽  
pp. C1124-C1133 ◽  
Author(s):  
Esther E. Dupont-Versteegden ◽  
John D. Houlé ◽  
Cathy M. Gurley ◽  
Charlotte A. Peterson
Keyword(s):  
Spinal Cord ◽  
Myosin Heavy Chain ◽  
Satellite Cell ◽  
Heavy Chain ◽  
Cell Activation ◽  
Fiber Type ◽  
Spinal Cord Transection ◽  
Fiber Types ◽  
Cell Nuclei ◽  
Muscle Plasticity

Muscles of spinal cord-transected rats exhibit severe atrophy and a shift toward a faster phenotype. Exercise can partially prevent these changes. The goal of this study was to investigate early events involved in regulating the muscle response to spinal transection and passive hindlimb exercise. Adult female Sprague-Dawley rats were anesthetized, and a complete spinal cord transection lesion (T10) was created in all rats except controls. Rats were killed 5 or 10 days after transection or they were exercised daily on motor-driven bicycles starting at 5 days after transection and were killed 0.5, 1, or 5 days after the first bout of exercise. Structural and biochemical features of soleus and extensor digitorum longus (EDL) muscles were studied. Atrophy was decreased in all fiber types of soleus and in type 2a and type 2x fibers of EDL after 5 days of exercise. However, exercise did not appear to affect fiber type that was altered within 5 days of spinal cord transection: fibers expressing myosin heavy chain 2x increased in soleus and EDL, and extensive coexpression of myosin heavy chain in soleus was apparent. Activation of satellite cells was observed in both muscles of transected rats regardless of exercise status, evidenced by increased accumulation of MyoD and myogenin. Increased expression was transient, except for MyoD, which remained elevated in soleus. MyoD and myogenin were detected both in myofiber and in satellite cell nuclei in both muscles, but in soleus, MyoD was preferentially expressed in satellite cell nuclei, and in EDL, MyoD was more readily detectable in myofiber nuclei, suggesting that MyoD and myogenin have different functions in different muscles. Exercise did not affect the level or localization of MyoD and myogenin expression. Similarly, Id-1 expression was transiently increased in soleus and EDL upon spinal cord transection, and no effect of exercise was observed. These results indicate that passive exercise can ameliorate muscle atrophy after spinal cord transection and that satellite cell activation may play a role in muscle plasticity in response to spinal cord transection and exercise. Finally, the mechanisms underlying maintenance of muscle mass are likely distinct from those controlling myosin heavy chain expression.

scholarly journals Immunohistochemical Analysis of Myosin Heavy Chain Expression in Laryngeal Muscles of the Rabbit, Cat, and Baboon

2008 ◽  
Vol 56 (10) ◽  
pp. 929-950 ◽  
Author(s):  
Hannah S. Rhee ◽  
Joseph F.Y. Hoh
Keyword(s):  
Myosin Heavy Chain ◽  
Heavy Chain ◽  
Fiber Type ◽  
Immunohistochemical Analysis ◽  
Muscle Fiber Types ◽  
Fiber Types ◽  
Laryngeal Muscles ◽  
Myhc Isoforms ◽  
Posterior Cricoarytenoid ◽  
Myhc Expression

We studied myosin heavy chain (MyHC) expression and fiber type distribution in laryngeal muscles in the rabbit, cat, and baboon using immunohistochemistry with highly MyHC-specific antibodies. Two types of variation in MyHC expression were found: between muscles of different function within species and within specific muscles between species. Within species, thyroarytenoid (Ta), an adductor, had faster MyHCs and fiber type profiles than the abductor, posterior cricoarytenoid (PCA), which expressed faster MyHCs than the vocal fold tensor, cricothyroid (CT). Between species, laryngeal muscles generally expressed faster MyHCs in small animals than in larger ones: extraocular (EO) MyHC was expressed in the Ta and PCA of the rabbit but not in the cat and baboon, whereas 2B MyHC was expressed in these muscles of the cat but not of the baboon. The CT expressed only MyHC isoforms and fiber types found in the limb muscles of the same species. These results are discussed in light of the hypothesis that the between-species variations in laryngeal muscle fiber types are evolutionary adaptations in response to changes in body mass and respiratory frequency. Within-species variations in fiber types ensure that protective closure of the glottis is always faster than movements regulating airflow during respiration.

Myosin Heavy Chain Composition and Fiber Size of the Cricopharyngeus Muscle in Patients with Achalasia and Normal Subjects

2007 ◽  
Vol 116 (9) ◽  
pp. 643-646 ◽  
Author(s):  
Melinda V. Davis ◽  
Albert L. Merati ◽  
Safwan S. Jaradeh ◽  
Joel H. Blumin
Keyword(s):  
Myosin Heavy Chain ◽  
Heavy Chain ◽  
Fiber Type ◽  
Normal Subjects ◽  
Type I ◽  
Cricopharyngeus Muscle ◽  
Type Composition ◽  
Fiber Size ◽  
The Difference ◽  
Type I Fibers

Objectives: Cricopharyngeal achalasia (CA) can be defined as inadequate opening of the cricopharyngeus muscle (CPM) resulting in dysphagia. Myosin heavy chain (MHC) isoform fiber type composition and size are key determinants of muscle function. These parameters have not been described in CA. It is hypothesized that there is a difference between the MHC isoform composition of the CPM in patients with the clinical diagnosis of CA and that in normal subjects. Methods: Patients who had received prior botulinum were excluded. The MHC fiber type composition and size in patients and cadaveric controls were determined by adenosine triphosphatase staining and image analysis. Results: The CPMs of 12 CA patients (6 male, 6 female; mean age, 61 years) and 5 control cadaveric subjects (3 male, 2 female; mean age, 67 years) were analyzed. There were relatively fewer type I fibers (67%) in patients with CA than in controls (81%), but the difference was not significant (p = 18). Type I fibers were slightly smaller in CA patients (38.7 μm) than in controls (47.2 μm), but this was not significantly different (p > 05). Of the 12 CA patients, 3 had type II predominance, a feature not seen in normal subjects. Conclusions: Patients with CA had relatively fewer type I fibers, although the difference was not statistically significant. The MHC isoform composition and fiber size were not different between CA patients and normal subjects. This is the first report to characterize the CPM in patients with CA.

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