scholarly journals Drugs for the Treatment of Muscle Atrophy

Author(s):  
Linlin Chen ◽  
Hong Zhang ◽  
Mengyi Chi ◽  
Quanjun Yang ◽  
Cheng Guo

Muscle mass is maintained through an interplay between anabolic and catabolic pathways. The ubiquitin-proteasome system plays an important role in the proteolysis progress during skeletal muscle atrophy which can be blocked by some proteasome inhibitors. But few studies have demonstrated the ability of these inhibitors to preserve muscle mass and architecture under catabolic condition in vivo. The insulin-like growth factor-1/phosphatidylinositide 3-kinases/protein kinase B/mammalian target of rapamycin (IGF-1/PI3K/Akt/mTOR) pathway was associated with anabolic pathways. The activation of IGF-1 causes muscle hypertrophy; however, it cannot be used as a drug target. Myostatin pathway maintains activation that can induce skeletal muscle atrophy involved with various transcriptional and genetic factors. Skeletal muscle atrophy is a debilitating consequence of multiple chronic diseases and conditions that involve starvation. It reduces treatment options and positive clinical outcomes as well as compromising quality of life and increasing morbidity and mortality. Though considerable research has been undertaken to find the drug target and the molecular mechanisms that improve skeletal muscle atrophy, no drug was approved to treat skeletal muscle atrophy. However, these years, the signaling pathways involved in muscle atrophy were clarified and some effective treatments were currently available to prevent, attenuate, or reverse muscle atrophy for experiment research.

2006 ◽  
Vol 231 (3) ◽  
pp. 335-341 ◽  
Author(s):  
Blake C. Beehler ◽  
Paul G. Sleph ◽  
Latifa Benmassaoud ◽  
Gary J. Grover

The ubiquitin-proteasome system is the primary proteolytic pathway implicated in skeletal muscle atrophy under catabolic conditions. Although several studies showed that proteasome inhibitors reduced proteolysis under catabolic conditions, few studies have demonstrated the ability of these inhibitors to preserve skeletal muscle mass and architecture in vivo. To explore this, we studied the effect of the proteasome inhibitor Velcade (also known as PS-341 and bortezomib) in denervated skeletal muscle in rats. Rats were given vehicle or Velcade (3 mg/kg po) daily for 7 days beginning immediately after induction of muscle atrophy by crushing the sciatic nerve. At the end of the study, the rats were euthanized and the soleus and extensor digitorum longus (EDL) muscles were harvested. In vehicle-treated rats, denervation caused a 33.5 ± 2.8% and 16.2 ± 2.7% decrease in the soleus and EDL muscle wet weights (% atrophy), respectively, compared to muscles from the contralateral (innervated) limb. Velcade significantly reduced denervation-induced atrophy to 17.1 ± 3.3% in the soleus (P < 0.01), a 51.6% reduction in atrophy associated with denervation, with little effect on the EDL (9.8 ± 3.2% atrophy). Histology showed a Preservation of muscle mass and preservation of normal cellular architecture after Velcade treatment. Ubiquitin mRNA levels in denervated soleus muscle at the end of the study were significantly elevated 120 ± 25% above sham control levels and were reduced to control levels by Velcade. In contrast, testosterone proprionate (3 mg/kg sc) did not alleviate denervation-induced skeletal muscle atrophy but did prevent castration-induced levator ani atrophy, while Velcade was without effect. These results show that proteasome inhibition attenuates denervation-induced muscle atrophy in vivo in soleus muscles. However, this mechanism may not be operative in all types of atrophy.


2020 ◽  
Vol 21 (18) ◽  
pp. 6663 ◽  
Author(s):  
Dulce Peris-Moreno ◽  
Daniel Taillandier ◽  
Cécile Polge

The E3 ubiquitin ligase MuRF1/TRIM63 was identified 20 years ago and suspected to play important roles during skeletal muscle atrophy. Since then, numerous studies have been conducted to decipher the roles, molecular mechanisms and regulation of this enzyme. This revealed that MuRF1 is an important player in the skeletal muscle atrophy process occurring during catabolic states, making MuRF1 a prime candidate for pharmacological treatments against muscle wasting. Indeed, muscle wasting is an associated event of several diseases (e.g., cancer, sepsis, diabetes, renal failure, etc.) and negatively impacts the prognosis of patients, which has stimulated the search for MuRF1 inhibitory molecules. However, studies on MuRF1 cardiac functions revealed that MuRF1 is also cardioprotective, revealing a yin and yang role of MuRF1, being detrimental in skeletal muscle and beneficial in the heart. This review discusses data obtained on MuRF1, both in skeletal and cardiac muscles, over the past 20 years, regarding the structure, the regulation, the location and the different functions identified, and the first inhibitors reported, and aim to draw the picture of what is known about MuRF1. The review also discusses important MuRF1 characteristics to consider for the design of future drugs to maintain skeletal muscle mass in patients with different pathologies.


2018 ◽  
Vol 50 (9) ◽  
pp. 746-757 ◽  
Author(s):  
Yoshitake Cho ◽  
Robert S. Ross

Immobilization, bed rest, or denervation leads to muscle disuse and subsequent skeletal muscle atrophy. Muscle atrophy can also occur as a component of various chronic diseases such as cancer, AIDS, sepsis, diabetes, and chronic heart failure or as a direct result of genetic muscle disorders. In addition to this atrophic loss of muscle mass, metabolic deregulation of muscle also occurs. In contrast, physical exercise plays a beneficial role in counteracting disuse-induced atrophy by increasing muscle mass and strength. Along with this, exercise can also reduce mitochondrial dysfunction and metabolic deregulation. Still, while exercise causes valuable metabolic and functional adaptations in skeletal muscle, the mechanisms and effectors that lead to these changes such as increased mitochondria content or enhanced protein synthesis are not fully understood. Therefore, mechanistic insights may ultimately provide novel ways to treat disuse induced atrophy and metabolic deregulation. Mass spectrometry (MS)-based proteomics offers enormous promise for investigating the molecular mechanisms underlying disuse and exercise-induced changes in skeletal muscle. This review will focus on initial findings uncovered by using proteomics approaches with human skeletal muscle specimens and discuss their potential for the future study.


2016 ◽  
Vol 37 (5) ◽  
Author(s):  
Serge Summermatter ◽  
Anais Bouzan ◽  
Eliane Pierrel ◽  
Stefan Melly ◽  
Daniela Stauffer ◽  
...  

ABSTRACT Metallothioneins are proteins that are involved in intracellular zinc storage and transport. Their expression levels have been reported to be elevated in several settings of skeletal muscle atrophy. We therefore investigated the effect of metallothionein blockade on skeletal muscle anabolism in vitro and in vivo. We found that concomitant abrogation of metallothioneins 1 and 2 results in activation of the Akt pathway and increases in myotube size, in type IIb fiber hypertrophy, and ultimately in muscle strength. Importantly, the beneficial effects of metallothionein blockade on muscle mass and function was also observed in the setting of glucocorticoid addition, which is a strong atrophy-inducing stimulus. Given the blockade of atrophy and the preservation of strength in atrophy-inducing settings, these results suggest that blockade of metallothioneins 1 and 2 constitutes a promising approach for the treatment of conditions which result in muscle atrophy.


Author(s):  
Kazuhito Akama ◽  
Yasuka Shimajiri ◽  
Kumiko Kainou ◽  
Ryota Iwasaki ◽  
Reiko Nakao ◽  
...  

Abstract Ubiquitin ligase Cbl-b play a critical role in non-loading-mediated skeletal muscle atrophy: Cbl-b ubiquitinates insulin receptor substrate-1 (IRS-1), an important insulin-like growth factor-1 signaling intermediate molecule, leading to its degradation and a resulting loss in muscle mass. We reported that intramuscular injection of a pentapeptide, DGpYMP, which acts as a mimic of the phosphorylation site in IRS-1, significantly inhibited denervation-induced skeletal muscle loss. In order to explore the possibility of the prevention of muscle atrophy by diet therapy, we examined the effects of oral administration of transgenic rice containing Cblin (Cbl-b inhibitor) peptide (DGYMP) on denervation-induced muscle mass loss in frogs. We generated transgenic rice seeds in which 15 repeats of Cblin peptides with a WQ spacer were inserted into the rice storage protein glutelin for expression. A diet of the transgenic rice seeds had significant inhibitory effects on denervation-induced atrophy of the leg skeletal muscles in frogs, compared with those receiving a diet of wild-type rice.


Endocrinology ◽  
2010 ◽  
Vol 151 (10) ◽  
pp. 4696-4704 ◽  
Author(s):  
Steven T. Russell ◽  
Michael J. Tisdale

The mechanism by which the adipokine zinc-α2-glycoprotein (ZAG) increases the mass of gastrocnemius, but not soleus muscle of diabetic mice, has been evaluated both in vivo and in vitro. There was an increased phosphorylation of both double-stranded RNA-dependent protein kinase and its substrate, eukaryotic initiation factor-2α, which was attenuated by about two-thirds in gastrocnemius but not soleus muscle of ob/ob mice treated with ZAG (50 μg, iv daily) for 5 d. ZAG also reduced the expression of the phospho forms of p38MAPK and phospholipase A2, as well as expression of the ubiquitin ligases (E3) muscle atrophy F-box/atrogin-1 and muscle RING finger protein, and the increased activity of both caspase-3 and casapse-8 to values found in nonobese controls. ZAG also increased the levels of phospho serine-threonine kinase and mammalian target of rapamycin in gastrocnemius muscle and reduced the phosphorylation of insulin receptor substrate-1 (Ser307) associated with insulin resistance. Similar changes were seen with ZAG when murine myotubes were incubated with high glucose concentrations (10 and 25 mm), showing that the effect of ZAG was direct. ZAG produced an increase in cAMP in murine myotubes, and the effects of ZAG on protein synthesis and degradation in vitro could be replicated by dibutyryl cAMP. ZAG increased cAMP levels of gastrocnemius but not soleus muscle. These results suggest that protein accretion in skeletal muscle in response to ZAG may be due to changes in intracellular cAMP and also that ZAG may have a therapeutic application in the treatment of muscle wasting conditions.


2000 ◽  
Vol 89 (2) ◽  
pp. 823-839 ◽  
Author(s):  
Robert H. Fitts ◽  
Danny R. Riley ◽  
Jeffrey J. Widrick

Spaceflight (SF) has been shown to cause skeletal muscle atrophy; a loss in force and power; and, in the first few weeks, a preferential atrophy of extensors over flexors. The atrophy primarily results from a reduced protein synthesis that is likely triggered by the removal of the antigravity load. Contractile proteins are lost out of proportion to other cellular proteins, and the actin thin filament is lost disproportionately to the myosin thick filament. The decline in contractile protein explains the decrease in force per cross-sectional area, whereas the thin-filament loss may explain the observed postflight increase in the maximal velocity of shortening in the type I and IIa fiber types. Importantly, the microgravity-induced decline in peak power is partially offset by the increased fiber velocity. Muscle velocity is further increased by the microgravity-induced expression of fast-type myosin isozymes in slow fibers (hybrid I/II fibers) and by the increased expression of fast type II fiber types. SF increases the susceptibility of skeletal muscle to damage, with the actual damage elicited during postflight reloading. Evidence in rats indicates that SF increases fatigability and reduces the capacity for fat oxidation in skeletal muscles. Future studies will be required to establish the cellular and molecular mechanisms of the SF-induced muscle atrophy and functional loss and to develop effective exercise countermeasures.


2021 ◽  
Vol 37 (1) ◽  
Author(s):  
Akira Nemoto ◽  
Toru Goyagi

Abstract Background Sarcopenia promotes skeletal muscle atrophy and exhibits a high mortality rate. Its elucidation is of the highest clinical importance, but an animal experimental model remains controversial. In this study, we investigated a simple method for studying sarcopenia in rats. Results Muscle atrophy was investigated in 24-week-old, male, tail-suspended (TS), Sprague Dawley and spontaneously hypertensive rats (SHR). Age-matched SD rats were used as a control group. The skeletal muscle mass weight, muscle contraction, whole body tension (WBT), cross-sectional area (CSA), and Muscle RING finger-1 (MuRF-1) were assessed. Enzyme-linked immunosorbent assay was used to evaluate the MuRF-1 levels. Two muscles, the extensor digitorum longus and soleus muscles, were selected for representing fast and slow muscles, respectively. All data, except CSA, were analyzed by a one-way analysis of variance, whereas CSA was analyzed using the Kruskal-Wallis test. Muscle mass weight, muscle contraction, WBT, and CSA were significantly lower in the SHR (n = 7) and TS (n = 7) groups than in the control group, whereas MuRF-1 expression was dominant. Conclusions TS and SHR presented sarcopenic phenotypes in terms of muscle mass, muscle contraction and CSA. TS is a useful technique for providing muscle mass atrophy and weakness in an experimental model of sarcopenia in rats.


2020 ◽  
Vol 21 (5) ◽  
pp. 1628 ◽  
Author(s):  
Keisuke Hitachi ◽  
Masashi Nakatani ◽  
Shiori Funasaki ◽  
Ikumi Hijikata ◽  
Mizuki Maekawa ◽  
...  

Skeletal muscle is a highly plastic organ that is necessary for homeostasis and health of the human body. The size of skeletal muscle changes in response to intrinsic and extrinsic stimuli. Although protein-coding RNAs including myostatin, NF-κβ, and insulin-like growth factor-1 (IGF-1), have pivotal roles in determining the skeletal muscle mass, the role of long non-coding RNAs (lncRNAs) in the regulation of skeletal muscle mass remains to be elucidated. Here, we performed expression profiling of nine skeletal muscle differentiation-related lncRNAs (DRR, DUM1, linc-MD1, linc-YY1, LncMyod, Neat1, Myoparr, Malat1, and SRA) and three genomic imprinting-related lncRNAs (Gtl2, H19, and IG-DMR) in mouse skeletal muscle. The expression levels of these lncRNAs were examined by quantitative RT-PCR in six skeletal muscle atrophy models (denervation, casting, tail suspension, dexamethasone-administration, cancer cachexia, and fasting) and two skeletal muscle hypertrophy models (mechanical overload and deficiency of the myostatin gene). Cluster analyses of these lncRNA expression levels were successfully used to categorize the muscle atrophy models into two sub-groups. In addition, the expression of Gtl2, IG-DMR, and DUM1 was altered along with changes in the skeletal muscle size. The overview of the expression levels of lncRNAs in multiple muscle atrophy and hypertrophy models provides a novel insight into the role of lncRNAs in determining the skeletal muscle mass.


2003 ◽  
Vol 18 (1) ◽  
pp. 221-223 ◽  
Author(s):  
Mohammed Borhan Alzghoul ◽  
Dave Gerrard ◽  
Bruce A. Watkins ◽  
Kevin Hannon

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