scholarly journals Effects of Clenbuterol and Cyclosporin A on the Myosin Heavy Chain mRNA Level and the Muscle Mass in Rat Masseter

2006 ◽  
Vol 56 (3) ◽  
pp. 205-209 ◽  
Author(s):  
Chihiro Arai ◽  
Yoshiki Ohnuki ◽  
Daisuke Umeki ◽  
Ayao Hirashita ◽  
Yasutake Saeki
Keyword(s):  
Cyclosporin A ◽  
Myosin Heavy Chain ◽  
Muscle Mass ◽  
Heavy Chain ◽  
Mrna Level

scholarly journals Effects of Bite-Opening and Cyclosporin A on the mRNA Levels of Myosin Heavy Chain and the Muscle Mass in Rat Masseter

2005 ◽  
Vol 55 (3) ◽  
pp. 173-179 ◽  
Author(s):  
Chihiro Arai ◽  
Yoshiki Ohnuki ◽  
Daisuke Umeki ◽  
Yasutake Saeki
Keyword(s):  
Cyclosporin A ◽  
Myosin Heavy Chain ◽  
Muscle Mass ◽  
Heavy Chain ◽  
Mrna Levels

Glutamine prevents downregulation of myosin heavy chain synthesis and muscle atrophy from glucocorticoids

1995 ◽  
Vol 268 (4) ◽  
pp. E730-E734 ◽  
Author(s):  
R. C. Hickson ◽  
S. M. Czerwinski ◽  
L. E. Wegrzyn
Keyword(s):  
Protein Synthesis ◽  
Myosin Heavy Chain ◽  
Muscle Mass ◽  
Muscle Atrophy ◽  
Heavy Chain ◽  
Total Protein ◽  
Female Rats ◽  
Glucocorticoid Treatment ◽  
Precursor Pool ◽  
Chain Synthesis

The aims of this study were to determine whether glutamine infusion prevents the decline in protein synthesis and muscle wasting associated with repeated glucocorticoid treatment. Hormone (cortisol acetate, 100 mg.kg body wt-1.day-1) and vehicle (carboxymethyl cellulose)-treated female rats were infused with either saline or glutamine (240 mM, 0.75 ml/h) for a 7-day period. Glutamine infusion attenuated the decline of plantaris muscle glutamine concentration (3.0 +/- 0.2 vs. 2.3 +/- 0.2 mumol/g) and prevented > 70% of the total muscle mass losses due to the glucocorticoid injections. Fractional synthesis rates of myosin heavy chain (MHC) and total protein were determined after constant [3H]leucine infusion from the leucyl-tRNA precursor pool, which was similar in all groups (range 4.8 +/- 0.5 to 6.3 +/- 0.4 disintegrations.min-1.pmol-1). MHC synthesis rates (%/day) in plantaris muscles were reduced to approximately 40% of controls (4.2/9.4). Although glutamine had no effect on MHC synthesis in vehicle-treated animals (10.1/9.4), it prevented 50% (7.6/4.2) of the hormone-induced decline in MHC synthesis rates. The same results were obtained with total protein synthesis measurements. Changes in muscle mass did not appear related to estimates of protein breakdown. In conclusion, these data show that glutamine infusion is effective therapy in counteracting glucocorticoid-induced muscle atrophy. Atrophy attenuation appears related to maintaining muscle glutamine levels, which in turn may limit the glucocorticoid-mediated downregulation of MHC synthesis.

Effects of aging on in vivo synthesis of skeletal muscle myosin heavy-chain and sarcoplasmic protein in humans

1997 ◽  
Vol 273 (4) ◽  
pp. E790-E800 ◽  
Author(s):  
P. Balagopal ◽  
Olav E. Rooyackers ◽  
Deborah B. Adey ◽  
Philip A. Ades ◽  
K. Sreekumaran Nair
Keyword(s):  
Myosin Heavy Chain ◽  
Old Age ◽  
Muscle Mass ◽  
Heavy Chain ◽  
Contractile Function ◽  
Contractile Protein ◽  
Whole Body ◽  
Synthesis Rate ◽  
Sarcoplasmic Protein ◽  
Chain Synthesis

A decline in muscle mass and contractile function are prominent features of the sarcopenia of old age. Because myosin heavy chain is an important contractile protein, it was hypothesized that synthesis of this protein decreases in sarcopenia. The fractional synthesis rate of myosin heavy chain was measured simultaneously with rates of mixed muscle and sarcoplasmic proteins from the increment of [13C]leucine in these proteins purified from serial needle biopsy samples taken from 24 subjects (age: from 20 to 92 yr) during a primed continuous infusion ofl-[1-13C]leucine. A decline in synthesis rate of mixed muscle protein ( P < 0.01) and whole body protein ( P < 0.01) was observed from young to middle age with no further change with advancing age. An age-related decline of myosin heavy-chain synthesis rate was also observed ( P < 0.01), with progressive decline occurring from young, through middle, to old age. However, sarcoplasmic protein synthesis did not decline with age. Myosin heavy-chain synthesis rate was correlated with measures of muscle strength ( P < 0.05), circulating insulin-like growth factor I ( P < 0.01), and dehydroepiandrosterone sulfate ( P < 0.05) in men and women and free testosterone levels in men ( P < 0.01). A decline in the synthesis rate of myosin heavy chain implies a decreased ability to remodel this important muscle contractile protein and likely contributes to the declining muscle mass and contractile function in the elderly.

scholarly journals Decreased specific force and power production of muscle fibers from myostatin-deficient mice are associated with a suppression of protein degradation

2011 ◽  
Vol 111 (1) ◽  
pp. 185-191 ◽  
Author(s):  
Christopher L. Mendias ◽  
Erdan Kayupov ◽  
Joshua R. Bradley ◽  
Susan V. Brooks ◽  
Dennis R. Claflin
Keyword(s):  
Myosin Heavy Chain ◽  
Muscle Mass ◽  
Heavy Chain ◽  
Extensor Digitorum Longus ◽  
Isometric Force ◽  
Muscle Fibers ◽  
Force Production ◽  
Sectional Area ◽  
Cross Sectional ◽  
Maximum Isometric Force

Myostatin ( MSTN) is a member of the transforming growth factor-β superfamily of cytokines and is a negative regulator of skeletal muscle mass. Compared with MSTN+/+ mice, the extensor digitorum longus muscles of MSTN−/− mice exhibit hypertrophy, hyperplasia, and greater maximum isometric force production (Fo), but decreased specific maximum isometric force (sFo; Fo normalized by muscle cross-sectional area). The reason for the reduction in sFo was not known. Studies in myotubes indicate that inhibiting myostatin may increase muscle mass by decreasing the expression of the E3 ubiquitin ligase atrogin-1, which could impact the force-generating capacity and size of muscle fibers. To gain a greater understanding of the influence of myostatin on muscle contractility, we determined the impact of myostatin deficiency on the contractility of permeabilized muscle fibers and on the levels of atrogin-1 and ubiquitinated myosin heavy chain in whole muscle. We hypothesized that single fibers from MSTN−/− mice have a greater Fo, but no difference in sFo, and a decrease in atrogin-1 and ubiquitin-tagged myosin heavy chain levels. The results indicated that fibers from MSTN−/− mice have a greater cross-sectional area, but do not have a greater Fo and have a sFo that is significantly lower than fibers from MSTN+/+ mice. The extensor digitorum longus muscles from MSTN−/− mice also have reduced levels of atrogin-1 and ubiquitinated myosin heavy chain. These findings suggest that myostatin inhibition in otherwise healthy muscle increases the size of muscle fibers and decreases atrogin-1 levels, but does not increase the force production of individual muscle fibers.

scholarly journals Regulation of Myosin Heavy Chain Expression during Rat Skeletal Muscle Development In Vitro

2001 ◽  
Vol 12 (5) ◽  
pp. 1499-1508 ◽  
Author(s):  
Carol E. Torgan ◽  
Mathew P. Daniels
Keyword(s):  
Skeletal Muscle ◽  
T Cells ◽  
Cyclosporin A ◽  
Myosin Heavy Chain ◽  
Heavy Chain ◽  
Fiber Formation ◽  
Immunofluorescent Staining ◽  
Nuclear Factor ◽  
Activated T Cells

Signals that determine fast- and slow-twitch phenotypes of skeletal muscle fibers are thought to stem from depolarization, with concomitant contraction and activation of calcium-dependent pathways. We examined the roles of contraction and activation of calcineurin (CN) in regulation of slow and fast myosin heavy chain (MHC) protein expression during muscle fiber formation in vitro. Myotubes formed from embryonic day 21 rat myoblasts contracted spontaneously, and ∼10% expressed slow MHC after 12 d in culture, as seen by immunofluorescent staining. Transfection with a constitutively active form of calcineurin (CN*) increased slow MHC by 2.5-fold as determined by Western blot. This effect was attenuated 35% by treatment with tetrodotoxin and 90% by administration of the selective inhibitor of CN, cyclosporin A. Conversely, cyclosporin A alone increased fast MHC by twofold. Cotransfection with VIVIT, a peptide that selectively inhibits calcineurin-induced activation of the nuclear factor of activated T-cells, blocked the effect of CN* on slow MHC by 70% but had no effect on fast MHC. The results suggest that contractile activity-dependent expression of slow MHC is mediated largely through the CN–nuclear factor of activated T-cells pathway, whereas suppression of fast MHC expression may be independent of nuclear factor of activated T-cells.

scholarly journals Co-expression of multiple myosin heavy chain genes, in addition to a tissue-specific one, in extraocular musculature.

1985 ◽  
Vol 101 (2) ◽  
pp. 618-629 ◽  
Author(s):  
D F Wieczorek ◽  
M Periasamy ◽  
G S Butler-Browne ◽  
R G Whalen ◽  
B Nadal-Ginard
Keyword(s):  
Myosin Heavy Chain ◽  
Heavy Chain ◽  
Mrna Level ◽  
S1 Nuclease ◽  
Tissue Specific ◽  
Adult Rat ◽  
Mhc Genes ◽  
The Individual ◽  
Genomic Probes ◽  
Nuclease Mapping

We have investigated the developmental transitions of myosin heavy chain (MHC) gene expression in the rat extraocular musculature (EOM) at the mRNA level using S1-nuclease mapping techniques and at the protein level by polypeptide mapping and immunochemistry. We have isolated a genomic clone, designated lambda 10B3, corresponding to an MHC gene which is expressed in the EOM fibers (recti and oblique muscles) of the adult rat but not in hind limb muscles. Using cDNA and genomic probes for MHC genes expressed in skeletal (embryonic, neonatal, fast oxidative, fast glycolytic, and slow/cardiac beta-MHC), cardiac (alpha-MHC), and EOM (lambda 10B3) muscles, we demonstrate the concomitant expression at the mRNA level of at least six different MHC genes in adult EOM. Protein and immunochemical analyses confirm the presence of at least four different MHC types in EOM. Immunocytochemistry demonstrates that different myosin isozymes tend to segregate into individual myofibers, although some fibers seem to contain more than one MHC type. The results also show that the EOM fibers exhibit multiple patterns of MHC gene regulation. One set of fibers undergoes a sequence of isoform transitions similar to the one described for limb skeletal muscles, whereas other EOM myofiber populations arrest the MHC transition at the embryonic, neonatal/adult, or adult EOM-specific stage. Thus, the MHC gene family is not under the control of a strict developmental clock, but the individual genes can modify their expression by tissue-specific and/or environmental factors.

scholarly journals Let-7e-5p Regulates IGF2BP2, and Induces Muscle Atrophy

2021 ◽  
Vol 12 ◽  
Author(s):  
Takuro Okamura ◽  
Hiroshi Okada ◽  
Yoshitaka Hashimoto ◽  
Saori Majima ◽  
Takafumi Senmaru ◽  
...  
Keyword(s):  
Glucose Uptake ◽  
Myosin Heavy Chain ◽  
Muscle Mass ◽  
Muscle Atrophy ◽  
Heavy Chain ◽  
Mitochondrial Function ◽  
C2c12 Cells ◽  
Androgen Depletion

Background and AimsTo understand the role of microRNAs in muscle atrophy caused by androgen-depletion, we performed microarray analysis of microRNA expression in the skeletal muscles of Sham, orchiectomized (ORX), and androgen-treated ORX mice.MethodsTo clarify role and mechanisms of let-7e-5p in the muscle, the effect of let-7e-5p overexpression or knockdown on the expression of myosin heavy chain, glucose uptake, and mitochondrial function was investigated in C2C12 myotube cells. Moreover, we examined serum let-7e-5p levels among male subjects with type 2 diabetes.ResultsWe found that the expression of the miRNA, lethal (let)-7e-5p was significantly lower in ORX mice than that in Sham mice (p = 0.027); however, let-7e-5p expression in androgen-treated ORX mice was higher (p = 0.047). Suppression of let-7e-5p significantly upregulated the expression of myosin heavy chain, glucose uptake, and mitochondrial function. Real-time PCR revealed a possible regulation involving let-7e-5p and Igf2bp2 mRNA and protein in C2C12 cells. The serum let-7e-5p levels were significantly lower, which might be in compensation, in subjects with decreased muscle mass compared to subjects without decreased muscle mass. Let-7e-5p downregulates the expression of Igf2bp2 in myotube cells and inhibits the growth of the myosin heavy chain.ConclusionsBased on our study, serum level of let-7e-5p may be used as a potential diagnostic marker for muscle atrophy.

Repair of spinal cord transection and its effects on muscle mass and myosin heavy chain isoform phenotype

2007 ◽  
Vol 103 (5) ◽  
pp. 1808-1814 ◽  
Author(s):  
Yu-Shang Lee ◽  
Ching-Yi Lin ◽  
Vincent J. Caiozzo ◽  
Richard T. Robertson ◽  
Jen Yu ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Myosin Heavy Chain ◽  
Muscle Mass ◽  
Muscle Fiber ◽  
Soleus Muscle ◽  
Heavy Chain ◽  
Combined Treatment ◽  
Spinal Cord Transection ◽  
Type I ◽  
Cord Injury

A number of significant advances have been developed for treating spinal cord injury during the past two decades. The combination of peripheral nerve grafts and acidic fibroblast growth factor (hereafter referred to as PNG) has been shown to partially restore hindlimb function. However, very little is known about the effects of such treatments in restoring normal muscle phenotype. The primary goal of the current study was to test the hypothesis that PNG would completely or partially restore 1) muscle mass and muscle fiber cross-sectional area and 2) the slow myosin heavy chain phenotype of the soleus muscle. To test this hypothesis, we assigned female Sprague-Dawley rats to three groups: 1) sham control, 2) spinal cord transection (Tx), and 3) spinal cord transection plus PNG (Tx+PNG). Six months following spinal cord transection, the open-field test was performed to assess locomotor function, and then the soleus muscles were harvested and analyzed. SDS-PAGE for single muscle fiber was used to evaluate the myosin heavy chain (MHC) isoform expression pattern following the injury and treatment. Immunohistochemistry was used to identify serotonin (5-HT) fibers in the spinal cord. Compared with the Tx group, the Tx+PNG group showed 1) significantly improved Basso, Beattie, and Bresnahan scores (hindlimb locomotion test), 2) less muscle atrophy, 3) a higher percentage of slow type I fibers, and 4) 5-HT fibers distal to the lesion site. We conclude that the combined treatment of PNG is partially effective in restoring the muscle mass and slow phenotype of the soleus muscle in a T-8 spinal cord-transected rat model.

scholarly journals Expression of SERCA2a is independent of innervation in regenerating soleus muscle

2003 ◽  
Vol 285 (4) ◽  
pp. C853-C861 ◽  
Author(s):  
Ernő Zádor ◽  
Frank Wuytack
Keyword(s):  
Sarcoplasmic Reticulum ◽  
Myosin Heavy Chain ◽  
Soleus Muscle ◽  
Heavy Chain ◽  
Mrna Level ◽  
Myosin Heavy Chain Isoforms ◽  
Muscle Type ◽  
Protein Levels ◽  
Constitutively Active Mutants ◽  
Slow Type

The speed of contraction of a skeletal muscle largely depends on the myosin heavy chain isoforms (MyHC), whereas the relaxation is initiated and maintained by the sarcoplasmic reticulum Ca2+-ATPases (SERCA). The expression of the slow muscle-type myosin heavy chain I (MyHCI) is entirely dependent on innervation, but, as we show here, innervation is not required for the expression of the slow-type sarcoplasmic reticulum Ca2+-ATPase (SERCA2a) in regenerating soleus muscles of the rat, although it can play a modulator role. Remarkably, the SERCA2a level is even higher in denervated than in innervated regenerating soleus muscles on day 7 when innervation is expected to resume. Later, the level of SERCA2a protein declines in denervated regenerated muscles but it remains expressed, whereas the corresponding mRNA level is still increasing. SERCA1 (i.e., the fast muscle-type isoform) expression shows only minor changes in denervated regenerating soleus muscles compared with innervated regenerating controls. When the soleus nerve was transected instead of the sciatic nerve, SERCA2a and MyHCI expressions were found to be even more uncoupled because the MyHCI nearly completely disappeared, whereas the SERCA2a mRNA and protein levels decreased much less. The transfection of regenerating muscles with constitutively active mutants of the Ras oncogene, known to mimic the effect of innervation on the expression of MyHCI, did not affect SERCA2a expression. These results demonstrate that the regulation of SERCA2a expression is clearly distinct from that of the slow myosin in the regenerating soleus muscle and that SERCA2a expression is modulated by neuronal activity but is not entirely dependent on it.

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