scholarly journals The mechanisms of skeletal muscle atrophy in response to transient knockdown of the vitamin D receptor in vivo

2020 ◽  
Author(s):  
Joseph J. Bass ◽  
Abid A. Kazi ◽  
Colleen S. Deane ◽  
Asif Nakhuda ◽  
Stephen P. Ashcroft ◽  
...  
2003 ◽  
Vol 18 (1) ◽  
pp. 221-223 ◽  
Author(s):  
Mohammed Borhan Alzghoul ◽  
Dave Gerrard ◽  
Bruce A. Watkins ◽  
Kevin Hannon

Author(s):  
Kathryn W. Aguilar-Agon ◽  
Andrew J. Capel ◽  
Jacob W. Fleming ◽  
Darren J. Player ◽  
Neil R. W. Martin ◽  
...  

Abstract Skeletal muscle atrophy as a consequence of acute and chronic illness, immobilisation, muscular dystrophies and aging, leads to severe muscle weakness, inactivity and increased mortality. Mechanical loading is thought to be the primary driver for skeletal muscle hypertrophy, however the extent to which mechanical loading can offset muscle catabolism has not been thoroughly explored. In vitro 3D-models of skeletal muscle provide a controllable, high throughput environment and mitigating many of the ethical and methodological constraints present during in vivo experimentation. This work aimed to determine if mechanical loading would offset dexamethasone (DEX) induced skeletal muscle atrophy, in muscle engineered using the C2C12 murine cell line. Mechanical loading successfully offset myotube atrophy and functional degeneration associated with DEX regardless of whether the loading occurred before or after 24 h of DEX treatment. Furthermore, mechanical load prevented increases in MuRF-1 and MAFbx mRNA expression, critical regulators of muscle atrophy. Overall, we demonstrate the application of tissue engineered muscle to study skeletal muscle health and disease, offering great potential for future use to better understand treatment modalities for skeletal muscle atrophy.


2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Antonietta Mele ◽  
Adriano Fonzino ◽  
Francesco Rana ◽  
Giulia Maria Camerino ◽  
Michela De Bellis ◽  
...  

2020 ◽  
Vol 319 (4) ◽  
pp. C700-C719 ◽  
Author(s):  
David C. Hughes ◽  
Leslie M. Baehr ◽  
Julia R. Driscoll ◽  
Sarah A. Lynch ◽  
David S. Waddell ◽  
...  

Muscle-specific E3 ubiquitin ligases have been identified in muscle atrophy-inducing conditions. The purpose of the current study was to explore the functional role of F-box and leucine-rich protein 22 (Fbxl22), and a newly identified splice variant (Fbxl22–193), in skeletal muscle homeostasis and neurogenic muscle atrophy. In mouse C2C12 muscle cells, promoter fragments of the Fbxl22 gene were cloned and fused with the secreted alkaline phosphatase reporter gene to assess the transcriptional regulation of Fbxl22. The tibialis anterior muscles of male C57/BL6 mice (12–16 wk old) were electroporated with expression plasmids containing the cDNA of two Fbxl22 splice variants and tissues collected after 7, 14, and 28 days. Gastrocnemius muscles of wild-type and muscle-specific RING finger 1 knockout (MuRF1 KO) mice were electroporated with an Fbxl22 RNAi or empty plasmid and denervated 3 days posttransfection, and tissues were collected 7 days postdenervation. The full-length gene and novel splice variant are transcriptionally induced early (after 3 days) during neurogenic muscle atrophy. In vivo overexpression of Fbxl22 isoforms in mouse skeletal muscle leads to evidence of myopathy/atrophy, suggesting that both are involved in the process of neurogenic muscle atrophy. Knockdown of Fbxl22 in the muscles of MuRF1 KO mice resulted in significant additive muscle sparing 7 days after denervation. Targeting two E3 ubiquitin ligases appears to have a strong additive effect on protecting muscle mass loss with denervation, and these findings have important implications in the development of therapeutic strategies to treat muscle atrophy.


Author(s):  
Li Wang ◽  
Ming-Qing He ◽  
Xi-Yu Shen ◽  
Kang-Zhen Zhang ◽  
Can Zhao ◽  
...  

Skeletal muscle atrophy is one of the major side effects of high dose or sustained usage of glucocorticoids. Pyroptosis is a novel form of pro-inflammatory programmed cell death that may contribute to skeletal muscle injury. Trimetazidine, a well-known anti-anginal agent, can also improve skeletal muscle performance both in human and mice. We here showed that dexamethasone induced atrophy, evidenced by the increase of muscle atrophy F-box (Atrogin-1) and muscle ring finger 1 (MuRF1) expression , and the decrease of myotube diameter in C2C12 myotubes. Dexamethasone also induced pyroptosis, indicated by upregulated pyroptosis-related protein NLRP3, Caspase-1 and GSDMD. Knockdown of NLRP3 or GSDMD attenuated dexamethasone-induced myotube pyroptosis and atrophy. Trimetazidine administration ameliorated dexamethasone-induced muscle atrophy both in vivo and in vitro. Moreover, trimetazidine improved exercise tolerance, as evidenced by increased running distance and running time, as well as increased skeletal muscle mass in dexamethasone-treated mice. Mechanically, trimetazidine could reverse dexamethasone-induced activation of pyroptosis both in C2C12 myotubes and in mice. Taken together, our present study demonstrated that NLRP3/GSDMD pathway-mediated pyroptosis was involved in dexamethasone-induced skeletal muscle atrophy. Trimetazidine could partially alleviate dexamethasone-induced skeletal muscle atrophy, and increase the diameter of C2C12 myotubes via inhibiting pyroptosis. Thus, trimetazidine might be a potential therapeutic compound for the prevention of muscle atrophy in glucocorticoid-treated patients.


Nutrients ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 3731
Author(s):  
Suji Baek ◽  
Jisu Kim ◽  
Byung Seok Moon ◽  
Sun Mi Park ◽  
Da Eun Jung ◽  
...  

Sarcopenia- or cachexia-related muscle atrophy is due to imbalanced energy metabolism and oxidative stress-induced muscle dysfunction. Monoterpenes play biological and pharmacological reactive oxygen species (ROS) scavenging roles. Hence, we explored the effects of camphene, a bicyclic monoterpene, on skeletal muscle atrophy in vitro and in vivo. We treated L6 myoblast cells with camphene and then examined the ROS-related oxidative stress using Mito TrackerTM Red FM and anti-8-oxoguanine antibody staining. To investigate lipid metabolism, we performed real-time polymerase chain reactions, holotomographic microscopy, and respiratory gas analysis. Rat muscle atrophy in in vivo models was observed using 18F-fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography and immunocytochemistry. Camphene reversed the aberrant cell size and muscle morphology of L6 myoblasts under starvation and in in vivo models. Camphene also attenuated E3 ubiquitin ligase muscle RING-finger protein-1, mitochondrial fission, and 8-oxoguanine nuclear expression in starved myotubes and hydrogen peroxide (H2O2)-treated cells. Moreover, camphene significantly regulated lipid metabolism in H2O2-treated cells and in vivo models. These findings suggest that camphene may potentially affect skeletal muscle atrophy by regulating oxidative stress and lipid metabolism.


2019 ◽  
Vol 5 (2) ◽  
pp. 33 ◽  
Author(s):  
Keisuke Hitachi ◽  
Masashi Nakatani ◽  
Kunihiro Tsuchida

Skeletal muscle is a highly plastic tissue and decreased skeletal muscle mass (muscle atrophy) results in deteriorated motor function and perturbed body homeostasis. Myogenin promoter-associated long non-coding RNA (lncRNA) Myoparr promotes skeletal muscle atrophy caused by surgical denervation; however, the precise molecular mechanism remains unclear. Here, we examined the downstream genes of Myoparr during muscle atrophy following denervation of tibialis anterior (TA) muscles in C57BL/6J mice. Myoparr knockdown affected the expression of 848 genes. Sixty-five of the genes differentially regulated by Myoparr knockdown coded secretory proteins. Among these 65 genes identified in Myoparr-depleted skeletal muscles after denervation, we focused on the increased expression of growth/differentiation factor 5 (GDF5), an inhibitor of muscle atrophy. Myoparr knockdown led to activated bone morphogenetic protein (BMP) signaling in denervated muscles, as indicated by the increased levels of phosphorylated Smad1/5/8. Our detailed evaluation of downstream genes of Myoparr also revealed that Myoparr regulated differential gene expression between myogenic differentiation and muscle atrophy. This is the first report demonstrating the in vivo role of Myoparr in regulating BMP signaling in denervated muscles. Therefore, lncRNAs that have inhibitory activity on BMP signaling may be putative therapeutic targets for skeletal muscle atrophy.


2014 ◽  
Vol 11 (1) ◽  
pp. 47 ◽  
Author(s):  
Carla Domingues-Faria ◽  
Audrey Chanet ◽  
Jérôme Salles ◽  
Alexandre Berry ◽  
Christophe Giraudet ◽  
...  

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