scholarly journals Modulation of Muscle Atrophy, Fatigue and MLC Phosphorylation by MuRF1 as Indicated by Hindlimb Suspension Studies on MuRF1-KO Mice

2010 ◽  
Vol 2010 ◽  
pp. 1-9 ◽  
Author(s):  
Siegfried Labeit ◽  
Christine H. Kohl ◽  
Christian C. Witt ◽  
Dittmar Labeit ◽  
Jeong Jung ◽  
...  

MuRF1 is a member of the TRIM/RBCC superfamily, a gene family that encompasses a large variety of proteins, all sharing the conserved TRIM (TripartiteMotive) sequential array ofRING,B-box, and coiled-coil domains. Within this family, MuRF1(also named TRIM63) is a specialized member that contributes to the development of muscle atrophy and sarcopenia. Here we studied MuRF1's role in muscle atrophy during muscle unloading induced by hindlimb suspension. Consistent with previous studies, we found that MuRF1 inactivation leads to an attenuated muscle atrophy response. The amount of protection was higher as compared to the denervation model, and within the 10 day-suspension period the soleus muscle was spared from atrophy in MuRF1-KO mice. Contractility studies on hindlimb suspended muscle tissues suggested that MuRF1's functions extend beyond muscle trophicity and implicate MuRF1 in muscle fatigue and MLC phosphorylation control: soleus muscle from MuRF1-KO mice fatigued significantly faster and in addition showed a reduced posttetanic twitch potentiation. Thus the present work further established the role of MuRF1 in muscle atrophy and for the first time shows that MuRF1 plays a role in muscle fatigue and twitch potentiation.

2008 ◽  
pp. 601-611
Author(s):  
R Ferreira ◽  
MJ Neuparth ◽  
R Vitorino ◽  
HJ Appell ◽  
F Amado ◽  
...  

The purpose of this study was to investigate the occurrence and time-course of apoptosis in soleus skeletal muscle during the first 48 hours of unloading. Fifty Charles River mice were randomly divided into five groups (n=10 each) according to the time of hindlimb suspension (HS). Mice were suspended for 0 (Control), 6 (6HS), 12 (12HS), 24 (24HS), and 48 hours (48HS). Soleus muscle atrophy was confirmed by a significant decrease of 20 % in muscle-wet weight and of 5 % in the ratio protein concentration/muscle wet-weight observed after 48 hours of unloading. The apoptotic index, the AIF (apoptosis-inducing factor) and p53 expression presented their uppermost value (304 %, 241 % and 246 %, respectively) at 24HS, and were preceded by the highest activity of caspase-3 and -8 at 12HS (170 % and 218 %, respectively) and of Bax/Bcl-2 content at 6HS (160 %). There were no marked ultrastructural alterations until 24 hours of simulated weightlessness. Lysosomal autophagic activity and infiltration of phagocytic cells were observed at 24HS and 48HS and might have contributed to the degenerative changes noticed in both groups. Though not consistently supported by morphological evidences, the biochemical parameters sustain the concept that the occurrence of apoptosis parallels the soleus atrophic response in its early phase.


1992 ◽  
Vol 70 (6) ◽  
pp. 814-820 ◽  
Author(s):  
Souad Aboudrar ◽  
Dominique Desplanches ◽  
Fränzi Graber-von Bergen ◽  
Roland Favier ◽  
Ismahan Okyayuz-Baklouti ◽  
...  

The effects of torbafylline on the prevention of and the recovery from 5 weeks of hindlimb suspension induced atrophy were analyzed in rat soleus and extensor digitorum longus muscles. Muscle alterations were investigated by determining a suite of electrophysiological, histochemical, and muscle ultrastructural characteristics. Administration of torbafylline during the suspension period was ineffective in preventing any of the observed muscle atrophic changes. Application of torbafylline during the recovery period resulted in a faster recovery of some soleus muscle structural and functional properties. Mitochondrial volume densities and capillary to fiber ratios returned towards baseline values earlier in the recovery process with torbafylline. Furthermore, the drug significantly improved soleus muscle fatigue resistance 4 weeks after cessation of hindlimb suspension.Key words: xanthine, rat muscle contraction, histocytochemistry, mitochondria, capillaries.


2009 ◽  
Vol 39 (3) ◽  
pp. 219-226 ◽  
Author(s):  
John J. McCarthy ◽  
Karyn A. Esser ◽  
Charlotte A. Peterson ◽  
Esther E. Dupont-Versteegden

There is a growing recognition that noncoding RNAs (ncRNA) play an important role in the regulation of gene expression. A class of small (19–22 nt) ncRNAs, known as microRNAs (miRs), have received a great deal of attention lately because of their ability to repress gene expression through a unique posttranscriptional 3′-untranslated region (UTR) mechanism. The objectives of the current study were to identify miRs expressed in the rat soleus muscle and determine if their expression was changed in response to hindlimb suspension. Comprehensive profiling revealed 151 miRs were expressed in the soleus muscle and expression of 18 miRs were significantly ( P < 0.01) changed after 2 and/or 7 days of hindlimb suspension. The significant decrease (16%) in expression of muscle-specific miR-499 in response to hindlimb suspension was confirmed by RT-PCR and suggested activation of the recently proposed miR encoded by myosin gene (MyomiR) network during atrophy. Further analysis of soleus muscle subjected to hindlimb suspension for 28 days provided evidence consistent with MyomiR network repression of β-myosin heavy chain gene (β-MHC) expression. The significant downregulation of network components miR-499 and miR-208b by 40 and 60%, respectively, was associated with increased expression of Sox6 (2.2-fold) and Purβ (23%), predicted target genes of miR-499 and known repressors of β-MHC expression. A Sox6 3′-UTR reporter gene confirmed Sox6 is a target gene of miR-499. These results further expand the role of miRs in adult skeletal muscle and are consistent with a model in which the MyomiR network regulates slow myosin expression during muscle atrophy.


2007 ◽  
Vol 292 (5) ◽  
pp. C1636-C1644 ◽  
Author(s):  
Jos L. J. van der Velden ◽  
Ramon C. J. Langen ◽  
Marco C. J. M. Kelders ◽  
Jodil Willems ◽  
Emiel F. M. Wouters ◽  
...  

Muscle atrophy contributes to morbidity and mortality in aging and chronic disease, emphasizing the need to gain understanding of the mechanisms involved in muscle atrophy and (re)growth. We hypothesized that the magnitude of muscle regrowth during recovery from atrophy determines whether myonuclear accretion and myogenic differentiation are required and that insulin-like growth factor (IGF)-I/Akt/glycogen synthase kinase (GSK)-3β signaling differs between regrowth responses. To address this hypothesis we subjected mice to hindlimb suspension (HS) to induce atrophy of soleus (−40%) and plantaris (−27%) muscle. Reloading-induced muscle regrowth was complete after 14 days and involved an increase in IGF-IEa mRNA expression that coincided with Akt phosphorylation in both muscles. In contrast, phosphorylation and inactivation of GSK-3β were observed during soleus regrowth only. Furthermore, soleus but not plantaris regrowth involved muscle regeneration based on a transient increase in expression of histone 3.2 and myosin heavy chain-perinatal, which are markers of myoblast proliferation and differentiation, and a strong induction of muscle regulatory factor (MRF) expression. Experiments in cultured muscle cells showed that IGF-I-induced MRF expression is facilitated by inactivation of GSK-3β and selectively occurs in the myoblast population. This study suggests that induction of IGF-I expression and Akt phosphorylation during recovery from muscle atrophy is independent of the magnitude of muscle regrowth. Moreover, our data demonstrate for the first time that the regenerative response characterized by myoblast proliferation, differentiation, and increased MRF expression in recovering muscle is associated with the magnitude of regrowth and may be regulated by inactivation of GSK-3β.


2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Violetta V. Kravtsova ◽  
Vladimir V. Matchkov ◽  
Elena V. Bouzinova ◽  
Alexander N. Vasiliev ◽  
Irina A. Razgovorova ◽  
...  

This study examines the isoform-specific effects of short-term hindlimb suspension (HS) on the Na,K-ATPase in rat soleus muscle. Rats were exposed to 24–72 h of HS and we analyzed the consequences on soleus muscle mass and contractile parameters; excitability and the resting membrane potential (RMP) of muscle fibers; the electrogenic activity, protein, and mRNA content of theα1 andα2 Na,K-ATPase; the functional activity and plasma membrane localization of theα2 Na,K-ATPase. Our results indicate that 24–72 h of HS specifically decreases the electrogenic activity of the Na,K-ATPaseα2 isozyme and the RMP of soleus muscle fibers. This decrease occurs prior to muscle atrophy or any change in contractile parameters. Theα2 mRNA and protein content increased after 24 h of HS and returned to initial levels at 72 h; however, even the increased content was not able to restoreα2 enzyme activity in the disused soleus muscle. There was no change in the membrane localization ofα2 Na,K-ATPase. Theα1 Na,K-ATPase electrogenic activity, protein and mRNA content did not change. Our findings suggest that skeletal muscle use is absolutely required forα2 Na,K-ATPase transport activity and provide the first evidence that Na,K-ATPase alterations precede HS-induced muscle atrophy.


Nutrients ◽  
2017 ◽  
Vol 9 (10) ◽  
pp. 1100 ◽  
Author(s):  
Gabriel Nasri Marzuca-Nassr ◽  
Gilson Masahiro Murata ◽  
Amanda Roque Martins ◽  
Kaio Fernando Vitzel ◽  
Amanda Rabello Crisma ◽  
...  

2019 ◽  
Vol 20 (19) ◽  
pp. 4860 ◽  
Author(s):  
Alexey M. Petrov ◽  
Maria N. Shalagina ◽  
Vladimir A. Protopopov ◽  
Valeriy G. Sergeev ◽  
Sergey V. Ovechkin ◽  
...  

Lipid raft disruption is an early event during skeletal muscle unloading. Ceramide (Cer) serves as a signaling lipid that can contribute to lipid raft disturbance and muscle atrophy. Using biochemical and fluorescent approaches, the distribution of Cer and related molecules in the rat soleus muscle subjected to 12 h of hindlimb suspension (HS) was studied. HS led to upregulation of TNFα receptor 1 (TNFR1), Cer-producing enzymes, and acid and neutral sphingomyelinase (SMase) in detergent-resistant membranes (lipid rafts), which was accompanied by an increase in Cer and a decrease in sphingomyelin in this membrane fraction. Fluorescent labeling indicated increased Cer in the sarcoplasm as well as the junctional (synaptic) and extrajunctional compartments of the suspended muscles. Also, a loss of membrane asymmetry (a hallmark of membrane disturbance) was induced by HS. Pretreatment with clomipramine, a functional inhibitor of acid SMase, counteracted HS-mediated changes in the Cer/sphingomyelin ratio and acid SMase abundance as well as suppressed Cer accumulation in the intracellular membranes of junctional and extrajunctional regions. However, the elevation of plasma membrane Cer and disturbance of the membrane asymmetry were suppressed only in the junctional compartment. We suggest that acute HS leads to TNFR1 and SMase upregulation in the lipid raft fraction and deposition of Cer throughout the sarcolemma and intracellularly. Clomipramine-mediated downregulation of acid SMase can suppress Cer accumulation in all compartments, excluding the extrajunctional plasma membrane.


2016 ◽  
Vol 41 (12) ◽  
pp. 1240-1247 ◽  
Author(s):  
Jiwoong Jang ◽  
Jonghoon Park ◽  
Hyukki Chang ◽  
Kiwon Lim

l-Carnitine was recently found to downregulate the ubiquitin proteasome pathway (UPP) and increase insulin-like growth factor 1 concentrations in animal models. However, the effect of l-carnitine administration on disuse muscle atrophy induced by hindlimb suspension has not yet been studied. Thus, we hypothesized that l-carnitine may have a protective effect on muscle atrophy induced by hindlimb suspension via the Akt1/mTOR and/or UPP. Male Wistar rats were assigned to 3 groups: hindlimb suspension group, hindlimb suspension with l-carnitine administration (1250 mg·kg−1·day−1) group, and pair-fed group adjusted hindlimb suspension. l-Carnitine administration for 2 weeks of hindlimb suspension alleviated the decrease in weight and fiber size in the soleus muscle. In addition, l-carnitine suppressed atrogin-1 mRNA expression, which has been reported to play a pivotal role in muscle atrophy. The present study shows that l-carnitine has a protective effect against soleus muscle atrophy caused by hindlimb suspension and decreased E3 ligase messenger RNA expression, suggesting the possibility that l-carnitine protects against muscle atrophy, at least in part, through the inhibition of the UPP. These observations suggest that l-carnitine could serve as an effective supplement in the decrease of muscle atrophy caused by weightlessness in the fields of clinical and rehabilitative research.


Author(s):  
Evgeniya S. Shitova ◽  
Inga S. Malakhova ◽  
Vladislav I. Lemeshko

Introduction. The use of classical methods for diagnosing muscle fatigue of physical workers, including dynamometry and electromyography, is often limited due to the complexity of the process, the inability to use them in production, and the subjectivity of the methodology. At the same time, such a method as myotonometry does not have these disadvantages, but the main area of its use at the moment is clinical practice. The aim of study was to determine the possibility of using myotonometry to assess muscle fatigue. Materials and methods. In the course of the study, the biomechanical characteristics of muscles that differ in their depth were evaluated using the "MyotonPro" device (Myoton AS, Estonia). We determined the tone and stiffness of the biceps of the shoulder, the soleus muscle, and the muscle that straightens the back at different periods of time under the influence of maximum load on them. Results. It was found that the studied parameters of these muscles immediately after performing a series of exercises "to failure" statistically significantly increased, and after 30 minutes - again decreased, but did not reach the initial level. Conclusions. The myotonometric study showed objectivity, reliability, repeatability and proved to be one of the most promising modern methods for assessing muscle fatigue, including for solving problems in the field of occupational health.


2008 ◽  
Vol 34 (2) ◽  
pp. 149-161 ◽  
Author(s):  
Dawn J. Mazzatti ◽  
Melissa A. Smith ◽  
Radu C. Oita ◽  
Fei-Ling Lim ◽  
Andrew J. White ◽  
...  

A number of physiological changes follow prolonged skeletal muscle unloading as occurs in spaceflight, bed rest, and hindlimb suspension (HLS) and also in aging. These include muscle atrophy, fiber type switching, and loss of the ability to switch between lipid and glucose usage, or metabolic inflexibility. The signaling and genomic events that precede these physiological manifestations have not been investigated in detail, particularly in regard to loss of metabolic flexibility. Here we used gene arrays to determine the effects of 24-h HLS on metabolic remodeling in mouse muscle. Acute unloading resulted in differential expression of a number of transcripts in soleus and gastrocnemius muscle, including many involved in lipid and glucose metabolism. These include the peroxisome proliferator-activated receptors (PPARs). In contrast to Ppar-α and Ppar-γ, which were downregulated by acute HLS, Ppar-δ was upregulated concomitant with increased expression of its downstream target, uncoupling protein-3 ( Ucp-3). However, differential expression of Ppar-δ was both acute and transient in nature, suggesting that regulation of PPARδ may represent an adaptive, compensatory response aimed at regulating fuel utilization and maintaining metabolic flexibility.


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