scholarly journals Master Regulators of Muscle Atrophy: Role of Costamere Components

Cells ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 61
Author(s):  
Luisa Gorza ◽  
Matteo Sorge ◽  
Laura Seclì ◽  
Mara Brancaccio
Keyword(s):  
Muscle Mass ◽  
Muscle Atrophy ◽  
Mechanical Load ◽  
Lateral Force ◽  
Macromolecular Complexes ◽  
Master Regulators ◽  
Chaperone Protein ◽  
Biochemical Signals ◽  
Partial Effects

The loss of muscle mass and force characterizes muscle atrophy in several different conditions, which share the expression of atrogenes and the activation of their transcriptional regulators. However, attempts to antagonize muscle atrophy development in different experimental contexts by targeting contributors to the atrogene pathway showed partial effects in most cases. Other master regulators might independently contribute to muscle atrophy, as suggested by our recent evidence about the co-requirement of the muscle-specific chaperone protein melusin to inhibit unloading muscle atrophy development. Furthermore, melusin and other muscle mass regulators, such as nNOS, belong to costameres, the macromolecular complexes that connect sarcolemma to myofibrils and to the extracellular matrix, in correspondence with specific sarcomeric sites. Costameres sense a mechanical load and transduce it both as lateral force and biochemical signals. Recent evidence further broadens this classic view, by revealing the crucial participation of costameres in a sarcolemmal “signaling hub” integrating mechanical and humoral stimuli, where mechanical signals are coupled with insulin and/or insulin-like growth factor stimulation to regulate muscle mass. Therefore, this review aims to enucleate available evidence concerning the early involvement of costamere components and additional putative master regulators in the development of major types of muscle atrophy.

scholarly journals Expression Levels of Long Non-Coding RNAs Change in Models of Altered Muscle Activity and Muscle Mass

2020 ◽  
Vol 21 (5) ◽  
pp. 1628 ◽  
Author(s):  
Keisuke Hitachi ◽  
Masashi Nakatani ◽  
Shiori Funasaki ◽  
Ikumi Hijikata ◽  
Mizuki Maekawa ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Muscle Mass ◽  
Muscle Atrophy ◽  
Skeletal Muscle Mass ◽  
Muscle Size ◽  
Skeletal Muscle Atrophy ◽  
Myostatin Gene ◽  
Expression Levels ◽  
Non Coding Rnas

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.

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.

Muscle atrophy in cancer: a role for nutrition and exercise

2009 ◽  
Vol 34 (5) ◽  
pp. 950-956 ◽  
Author(s):  
Marina Mourtzakis ◽  
Megan Bedbrook
Keyword(s):  
Cancer Research ◽  
Body Composition ◽  
Cancer Patients ◽  
Muscle Mass ◽  
Muscle Atrophy ◽  
Exercise Interventions ◽  
Cancer Trajectory ◽  
Potential Factors ◽  
Primary Focus

Developing successful antineoplastic therapies has been a primary focus of cancer research, whereas less attention has been directed at body composition and metabolism in cancer patients. Here, we examine the metabolic implications of muscle atrophy in cancer as well as the potential factors that contribute to muscle atrophy, including energy imbalance, hormone perturbations, and inflammation. The role of nutrition and exercise interventions in maintaining muscle mass during the cancer trajectory is examined.

scholarly journals Lipid hydroperoxides promote muscle atrophy through lysosomal amplification

2021 ◽  
Author(s):  
Hiroaki Eshima ◽  
Piyarat Siripoksup ◽  
Justin L Shahtout ◽  
Mackenzie J Pearson ◽  
Ziad S Mahmassani ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Muscle Mass ◽  
Muscle Atrophy ◽  
Skeletal Muscle Atrophy ◽  
Lipid Hydroperoxides ◽  
Oxygen Species ◽  
Independent Manner ◽  
Generating Capacity ◽  
Cardinal Feature

Reactive oxygen species (ROS) is a cardinal feature of skeletal muscle atrophy. However, ROS refers to a collection of radical molecules whose cellular signals are vast, and it is unclear which downstream consequences of ROS are responsible for the loss of muscle mass and strength.1,2 Here we show that lipid hydroperoxides (LOOH) are increased with age and disuse, and the accumulation of LOOH by suppression of glutathione peroxidase 4 (GPx4) is sufficient to augment muscle atrophy. Strikingly, genetic and pharmacologic suppression of muscle LOOH robustly prevented the reduction of both muscle mass and force-generating capacity. LOOH promoted atrophy in a lysosomal-dependent, proteasomal-independent manner, and the suppression of autophagic machinery was sufficient to prevent muscle atrophy and weakness. Indeed, the lysosome is essential for the amplification of LOOH induced by oxidative stress. Our findings provide novel insights for the role of LOOH in muscle atrophy including a therapeutic implication by pharmacologic suppression.

MOLECULAR ASPECTS OF SARCOPENIA PATHOGENESIS IN CHRONOC KIDNEY DISEASE: INTEGRATED ROLE OF mTOR

2018 ◽  
Vol 22 (5) ◽  
pp. 9-16 ◽  
Author(s):  
M. Z. Gasanov
Keyword(s):  
Kidney Disease ◽  
Muscle Mass ◽  
Protein Metabolism ◽  
Mammalian Target Of Rapamycin ◽  
Healthy Person ◽  
Scientific Review ◽  
Cytoskeleton Organization ◽  
Molecular Aspects ◽  
End Stage

In recent decades, the main pathogenetic mechanisms for maintaining muscle mass and strength have been discovered. Most of the scientific papers on the molecular aspects of the  pathogenesis of sarcopenia were focused on the Akt-signaling  pathway. The subject of the study were people of elderly and senile  age, immobilized patients, patients with CKD 1-4 stages, animals. However, recently more attention has been paid to the role  of protein – the mammalian target of rapamycin mTOR. It seems to be a key link in the control of muscle mass and is a promising  marker in understanding the mechanisms of the pathogenesis of  sarcopenia. Its importance in protein metabolism in patients with  end stage kidney disease is not studied and requires further research. The presented scientific review contains  information on the role of mTOR and its components – mTORC1 and mTORC2 in maintaining muscle mass and strength in a healthy  person and in the formation of sarcopenia in patients with CKD. The  general aid of mTORC1 complex is regulation of protein production  which is necessary for cell growth and differentiation. mTORC2  complex functions are not enough studied. It is established that it  plays important role in such biological processes as cytoskeleton  organization, intracellular homeostasis maintaining, so it provides  cell resistance and cell survivability in negative external and internal  impulses. mTOR protein can be considered as promising molecular  marker in diagnostics of protein metabolism early disturbances in  patients with CKD and also as additory factor of sarcopenia severity assessment.

scholarly journals Transcriptome analysis of gravitational effects on mouse skeletal muscles under microgravity and artificial 1 g onboard environment

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Risa Okada ◽  
Shin-ichiro Fujita ◽  
Riku Suzuki ◽  
Takuto Hayashi ◽  
Hirona Tsubouchi ◽  
...  
Keyword(s):  
Gene Expression ◽  
Muscle Mass ◽  
Muscle Atrophy ◽  
Transcriptome Analysis ◽  
Fiber Type ◽  
Expression Profiles ◽  
Space Station ◽  
Gene Expression Profiles

AbstractSpaceflight causes a decrease in skeletal muscle mass and strength. We set two murine experimental groups in orbit for 35 days aboard the International Space Station, under artificial earth-gravity (artificial 1 g; AG) and microgravity (μg; MG), to investigate whether artificial 1 g exposure prevents muscle atrophy at the molecular level. Our main findings indicated that AG onboard environment prevented changes under microgravity in soleus muscle not only in muscle mass and fiber type composition but also in the alteration of gene expression profiles. In particular, transcriptome analysis suggested that AG condition could prevent the alterations of some atrophy-related genes. We further screened novel candidate genes to reveal the muscle atrophy mechanism from these gene expression profiles. We suggest the potential role of Cacng1 in the atrophy of myotubes using in vitro and in vivo gene transductions. This critical project may accelerate the elucidation of muscle atrophy mechanisms.

scholarly journals Identification of Withania somnifera-Silybum marianum-Trigonella foenum-graecum Formulation as a Nutritional Supplement to Contrast Muscle Atrophy and Sarcopenia

Nutrients ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 49
Author(s):  
Laura Salvadori ◽  
Manuela Mandrone ◽  
Tommaso Manenti ◽  
Catia Ercolani ◽  
Luca Cornioli ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Muscle Mass ◽  
Muscle Atrophy ◽  
Withania Somnifera ◽  
Myoblast Differentiation ◽  
C2c12 Myotubes ◽  
Silybum Marianum ◽  
Trigonella Foenum Graecum ◽  
Age Related

Background: Muscle atrophy, i.e., the loss of skeletal muscle mass and function, is an unresolved problem associated with aging (sarcopenia) and several pathological conditions. The imbalance between myofibrillary protein breakdown (especially the adult isoforms of myosin heavy chain, MyHC) and synthesis, and the reduction of muscle regenerative potential are main causes of muscle atrophy. Methods: Starting from one-hundred dried hydroalcoholic extracts of medical plants, we identified those able to contrast the reduction of C2C12 myotube diameter in well-characterized in vitro models mimicking muscle atrophy associated to inflammatory states, glucocorticoid treatment or nutrient deprivation. Based on their ability to rescue type II MyHC (MyHC-II) expression in atrophying conditions, six extracts with different phytochemical profiles were selected, mixed in groups of three, and tested on atrophic myotubes. The molecular mechanism underpinning the effects of the most efficacious formulation, and its efficacy on myotubes obtained from muscle biopsies of young and sarcopenic subjects were also investigated. Results: We identified WST (Withania somnifera, Silybum marianum, Trigonella foenum-graecum) formulation as extremely efficacious in protecting C2C12 myotubes against MyHC-II degradation by stimulating Akt (protein kinase B)-dependent protein synthesis and p38 MAPK (p38 mitogen-activated protein kinase)/myogenin-dependent myoblast differentiation. WST sustains trophism in C2C12 and young myotubes, and rescues the size, developmental MyHC expression and myoblast fusion in sarcopenic myotubes. Conclusion: WST strongly counteracts muscle atrophy associated to different conditions in vitro. The future validation in vivo of our results might lead to the use of WST as a food supplement to sustain muscle mass in diffuse atrophying conditions, and to reverse the age-related functional decline of human muscles, thus improving people quality of life and reducing social and health-care costs.

scholarly journals Tail suspension is useful as a sarcopenia model in rats

2021 ◽  
Vol 37 (1) ◽  
Author(s):  
Akira Nemoto ◽  
Toru Goyagi
Keyword(s):  
Skeletal Muscle ◽  
Muscle Contraction ◽  
Experimental Model ◽  
Muscle Mass ◽  
Muscle Atrophy ◽  
Whole Body ◽  
Skeletal Muscle Atrophy ◽  
Enzyme Linked Immunosorbent Assay ◽  
Control Group ◽  
Simple Method

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.

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