scholarly journals Electrical Impedance as a Novel Biomarker of Myotube Atrophy and Hypertrophy

2011 ◽  
Vol 16 (6) ◽  
pp. 565-574 ◽  
Author(s):  
Sergey Rakhilin ◽  
Gordon Turner ◽  
Mark Katz ◽  
Robert Warden ◽  
Jeff Irelan ◽  
...  
Keyword(s):  
Muscle Atrophy ◽  
Electrical Impedance ◽  
Cellular Adhesion ◽  
Skeletal Muscle Atrophy ◽  
Novel Treatments ◽  
Novel Method ◽  
Quantitative Changes ◽  
Atrophy And Hypertrophy ◽  
Myotube Hypertrophy ◽  
Therapeutic Compounds

Measuring myotube thickness is a physiological and unbiased approach for screening therapeutic compounds that prevent skeletal muscle atrophy or induce hypertrophy. However, an accurate cell thickness estimate is often quite challenging because of the extreme heterogeneity of the myotube cellular population and therefore the lack of a regular distribution of perturbed myotubes. Here the authors present a novel method to evaluate changes in myotube thickness via measuring cellular electrical impedance. They demonstrate that both qualitative and quantitative changes in electrical impedance as a function of cellular adhesion in real time correlate well with variation in myotube thickness caused by atrophy or hypertrophy agents. Conversely, pharmacologically blocking myotube hypertrophy prevents changes in electrical impedance. Thus, impedance can be used as a reliable and sensitive biomarker for myotube atrophy or hypertrophy. Application of this technique to drug screening might be beneficial in finding novel treatments preventing muscle atrophy and other diseases associated with any morphological change in cell shape.

Myostatin and the skeletal muscle atrophy and hypertrophy signaling pathways

2014 ◽  
Vol 71 (22) ◽  
pp. 4361-4371 ◽  
Author(s):  
J. Rodriguez ◽  
B. Vernus ◽  
I. Chelh ◽  
I. Cassar-Malek ◽  
J. C. Gabillard ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Signaling Pathways ◽  
Muscle Atrophy ◽  
Skeletal Muscle Atrophy ◽  
Atrophy And Hypertrophy

scholarly journals UBR5 is a Novel E3 Ubiquitin Ligase involved in Skeletal Muscle Hypertrophy and Recovery from Atrophy

2019 ◽  
Author(s):  
RA Seaborne ◽  
DC Hughes ◽  
DC Turner ◽  
DJ Owens ◽  
LM Baehr ◽  
...  
Keyword(s):  
Gene Expression ◽  
Skeletal Muscle ◽  
Muscle Atrophy ◽  
Ubiquitin Ligase ◽  
Protein Level ◽  
E3 Ubiquitin Ligase ◽  
Skeletal Muscle Atrophy ◽  
Muscle Fibres ◽  
E3 Ligases ◽  
Atrophy And Hypertrophy

AbstractWe aimed to investigate a novel and uncharacterised E3 ubiquitin ligase in skeletal muscle atrophy, recovery from atrophy/injury, anabolism and hypertrophy. We demonstrated an alternate gene expression profile for UBR5 versus well characterised E3-ligases, MuRF1/MAFbx, where after atrophy evoked by continuous-low-frequency electrical-stimulation in rats, MuRF1/MAFbx were both elevated yet UBR5 was unchanged. Furthermore, after recovery of muscle mass post tetrodotoxin (TTX) induced-atrophy in rats, UBR5 was hypomethylated and increased at the gene expression level, while a suppression of MuRF1/MAFbx was observed. At the protein level, we also demonstrated a significant increase in UBR5 after recovery of muscle mass from hindlimb unloading in both adult and aged rats, and after recovery from atrophy evoked by nerve crush injury in mice. During anabolism and hypertrophy, UBR5 gene expression increased following acute loading in three-dimensional bioengineered mouse muscle in-vitro, and after chronic electrical-stimulation-induced hypertrophy in rats in-vivo, without increases in MuRF1/MAFbx. Additionally, UBR5 protein abundance increased following functional overload-induced hypertrophy of the plantaris muscle in mice and during differentiation of primary human muscle cells. Finally, in humans, genetic association studies (>700,000 SNPs) demonstrated that the A alleles of rs10505025 and rs4734621 SNPs in the UBR5 gene were strongly associated with larger cross-sectional area of fast-twitch muscle fibres and favoured strength/power versus endurance/untrained phenotypes. Overall, we suggest that UBR5 is a novel E3 ubiquitin ligase that is inversely regulated to MuRF1/MAFbx, is epigenetically regulated, and is elevated at both the gene expression and protein level during recovery from skeletal muscle atrophy and hypertrophy.Key PointsWe have recently identified that a HECT domain E3 ubiquitin ligase, named UBR5, is altered epigenetically (via DNA methylation) after human skeletal muscle hypertrophy, where its gene expression is positively correlated with increasing lean leg mass after training and retraining.In the present study we extensively investigate this novel and uncharacterised E3 ubiquitin ligase (UBR5) in skeletal muscle atrophy, recovery from atrophy and injury, anabolism and hypertrophy.We demonstrated that UBR5 was epigenetically via altered DNA methylation during recovery from atrophy.We also determined that UBR5 was alternatively regulated versus well characterised E3 ligases, MuRF1/MAFbx, at the gene expression level during atrophy, recovery from atrophy and hypertrophy.UBR5 also increased at the protein level during recovery from atrophy and injury, hypertrophy and during human muscle cell differentiation.Finally, in humans, genetic variations of the UBR5 gene were strongly associated with larger fast-twitch muscle fibres and strength/power performance versus endurance/untrained phenotypes.

scholarly journals DEVELOPMENT OF A NOVEL METHOD TO ASSESS SKELETAL MUSCLE ATROPHY IN COLLAGEN INDUCED ARTHRITIS (CIA) MODEL

2019 ◽  
Author(s):  
BARBARA JONSON BARTIKOSKI ◽  
THALES HEIN DA ROSA ◽  
THAIS KARNOPP ◽  
RENATA BARBARA PEDÓ ◽  
MANUELA BARBARA SANTOS ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Muscle Atrophy ◽  
Skeletal Muscle Atrophy ◽  
Collagen Induced Arthritis ◽  
Novel Method

scholarly journals Docosahexaenoic Acid Protects Muscle Cells from Palmitate-Induced Atrophy

ISRN Obesity ◽  
2012 ◽  
Vol 2012 ◽  
pp. 1-14 ◽  
Author(s):  
Randall W. Bryner ◽  
Myra E. Woodworth-Hobbs ◽  
David L. Williamson ◽  
Stephen E. Alway
Keyword(s):  
Skeletal Muscle ◽  
Fatty Acids ◽  
Docosahexaenoic Acid ◽  
Muscle Atrophy ◽  
Muscle Growth ◽  
Muscle Cells ◽  
Skeletal Muscle Atrophy ◽  
Omega 3 ◽  
Myotube Hypertrophy

Background. Accumulation of free fatty acids leads to lipid-toxicity-associated skeletal muscle atrophy. Palmitate treatment reduces myoblast and myotube growth and causes apoptosis in vitro. It is not known if omega-3 fatty acids will protect muscle cells against palmitate toxicity. Therefore, we examined the effects of docosahexaenoic acid (DHA) on skeletal muscle growth. Methods. Mouse myoblasts (C2C12) were differentiated to myotubes, and then treated with 0 or 0.5 mM palmitic acid or 0 or 0.1 mM DHA. Results. Intramyocellular lipid was increased in palmitate-treated cells but was prevented by DHA-palmitate cotreatment. Total AMPK increased in DHA+ palmitate-treated compared to palmitate only cells. RpS6 phosphorylation decreased after palmitate (−55%) and this was blunted by DHA+ palmitate (−35%) treatment. Palmitate treatment decreased PGC1 protein expression by 69%, but was increased 165% with DHA+ palmitate () versus palmitate alone. While palmitate induced 25% and 90% atrophy in myotubes (after 48 hours and 96 hours, resp.), DHA+ palmitate treatment caused myotube hypertrophy of ~50% and 100% after 48 and 96 hours, respectively. Conclusion. These data show that DHA is protective against palmitate-induced atrophy. Although DHA did not activate the AMPK pathway, DHA treatment restored growth-signaling (i.e., rpS6) and rescued palmitate-induced muscle atrophy.

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