scholarly journals Circadian clock regulation of skeletal muscle growth and repair

F1000Research ◽  
2016 ◽  
Vol 5 ◽  
pp. 1549 ◽  
Author(s):  
Somik Chatterjee ◽  
Ke Ma

Accumulating evidence indicates that the circadian clock, a transcriptional/translational feedback circuit that generates ~24-hour oscillations in behavior and physiology, is a key temporal regulatory mechanism involved in many important aspects of muscle physiology. Given the clock as an evolutionarily-conserved time-keeping mechanism that synchronizes internal physiology to environmental cues, locomotor activities initiated by skeletal muscle enable entrainment to the light-dark cycles on earth, thus ensuring organismal survival and fitness. Despite the current understanding of the role of molecular clock in preventing age-related sarcopenia, investigations into the underlying molecular pathways that transmit clock signals to the maintenance of skeletal muscle growth and function are only emerging. In the current review, the importance of the muscle clock in maintaining muscle mass during development, repair and aging, together with its contribution to muscle metabolism, will be discussed. Based on our current understandings of how tissue-intrinsic muscle clock functions in the key aspects muscle physiology, interventions targeting the myogenic-modulatory activities of the clock circuit may offer new avenues for prevention and treatment of muscular diseases. Studies of mechanisms underlying circadian clock function and regulation in skeletal muscle warrant continued efforts.

2003 ◽  
Vol 15 (9) ◽  
pp. 56
Author(s):  
A. Axell ◽  
H. E. MacLean ◽  
D. Plant ◽  
M. Jimenez ◽  
D. J. Handelsman ◽  
...  

1997 ◽  
Vol 272 (2) ◽  
pp. C565-C571 ◽  
Author(s):  
P. E. Mozdziak ◽  
E. Schultz ◽  
R. G. Cassens

The role of satellite cells and DNA unit size in determining skeletal muscle growth was studied after mitotic activity was inhibited in the left pectoralis thoracicus of 2-wk-old tom turkeys by means of a 25-Gy dose of irradiation. Toms were killed and muscle weights were obtained 1 (n = 5), 4 (n = 6), 7 (n = 6), and 15 (n = 4) wk after irradiation. Satellite cell mitotic activity and DNA unit size were determined using enzymatically isolated myofiber segments and image analysis. Irradiated and nonirradiated muscle weights increased (P < 0.01) between all ages examined, but irradiated muscle weights were significantly (P < 0.01) lower than nonirradiated muscle weights at 4, 7, and 15 wk after irradiation. Satellite cell mitotic activity was lower (P < 0.01) in irradiated than in nonirradiated muscles at 1 and 4 wk after irradiation and resulted in a significant reduction (P < 0.05) in the number of myofiber nuclei per millimeter at 4 and 7 wk after irradiation. Satellite cell mitotic activity was higher (P < 0.05) in irradiated than in nonirradiated muscles at 7 wk after irradiation, but at 15 wk after irradiation it had fallen to low levels in both muscles. There was no significant (P > 0.10) difference in DNA unit size between muscles at any time, but there was an age-related increase (P < 0.01) for both muscles. Irradiation reduced muscle growth through a transient reduction in myonuclear production at a critical time (3-6 wk of age) in posthatch skeletal muscle development. The age-related increase in DNA unit size was not accelerated to compensate for the reduction in myonuclear accretion. Thus it appears that muscle growth potential is governed mostly by myonuclear accretion and to a lesser extent by DNA unit size.


2021 ◽  
Vol 12 ◽  
Author(s):  
Chrystalla Mytidou ◽  
Andrie Koutsoulidou ◽  
Margarita Zachariou ◽  
Marianna Prokopi ◽  
Konstantinos Kapnisis ◽  
...  

Skeletal muscle growth and maintenance depend on two tightly regulated processes, myogenesis and muscle regeneration. Both processes involve a series of crucial regulatory molecules including muscle-specific microRNAs, known as myomiRs. We recently showed that four myomiRs, miR-1, miR-133a, miR-133b, and miR-206, are encapsulated within muscle-derived exosomes and participate in local skeletal muscle communication. Although these four myomiRs have been extensively studied for their function in muscles, no information exists regarding their endogenous and exosomal levels across age. Here we aimed to identify any age-related changes in the endogenous and muscle-derived exosomal myomiR levels during acute skeletal muscle growth. The four endogenous and muscle-derived myomiRs were investigated in five skeletal muscles (extensor digitorum longus, soleus, tibialis anterior, gastrocnemius, and quadriceps) of 2-week–1-year-old wild-type male mice. The expression of miR-1, miR-133a, and miR-133b was found to increase rapidly until adolescence in all skeletal muscles, whereas during adulthood it remained relatively stable. By contrast, endogenous miR-206 levels were observed to decrease with age in all muscles, except for soleus. Differential expression of the four myomiRs is also inversely reflected on the production of two protein targets; serum response factor and connexin 43. Muscle-derived exosomal miR-1, miR-133a, and miR-133b levels were found to increase until the early adolescence, before reaching a plateau phase. Soleus was found to be the only skeletal muscle to release exosomes enriched in miR-206. In this study, we showed for the first time an in-depth longitudinal analysis of the endogenous and exosomal levels of the four myomiRs during skeletal muscle development. We showed that the endogenous expression and extracellular secretion of the four myomiRs are associated to the function and size of skeletal muscles as the mice age. Overall, our findings provide new insights for the myomiRs’ significant role in the first year of life in mice.


Metabolites ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 855
Author(s):  
Federica Rossin ◽  
Elena Avitabile ◽  
Giorgia Catarinella ◽  
Ersilia Fornetti ◽  
Stefano Testa ◽  
...  

Skeletal muscle is a very dynamic and plastic tissue, being essential for posture, locomotion and respiratory movement. Muscle atrophy or genetic muscle disorders, such as muscular dystrophies, are characterized by myofiber degeneration and replacement with fibrotic tissue. Recent studies suggest that changes in muscle metabolism such as mitochondrial dysfunction and dysregulation of intracellular Ca2+ homeostasis are implicated in many adverse conditions affecting skeletal muscle. Accumulating evidence also suggests that ER stress may play an important part in the pathogenesis of inflammatory myopathies and genetic muscle disorders. Among the different known proteins regulating ER structure and function, we focused on RTN-1C, a member of the reticulon proteins family localized on the ER membrane. We previously demonstrated that RTN-1C expression modulates cytosolic calcium concentration and ER stress pathway. Moreover, we recently reported a role for the reticulon protein in autophagy regulation. In this study, we found that muscle differentiation process positively correlates with RTN-1C expression and UPR pathway up-regulation during myogenesis. To better characterize the role of the reticulon protein alongside myogenic and muscle regenerative processes, we performed in vivo experiments using either a model of muscle injury or a photogenic model for Duchenne muscular dystrophy. The obtained results revealed RTN-1C up-regulation in mice undergoing active regeneration and localization in the injured myofibers. The presented results strongly suggested that RTN-1C, as a protein involved in key aspects of muscle metabolism, may represent a new target to promote muscle regeneration and repair upon injury.


2017 ◽  
pp. 1-7
Author(s):  
L.A. CONSITT ◽  
B.C. CLARK

The age-related loss of skeletal muscle (sarcopenia) is a major health concern as it is associated with physical disability, metabolic impairments, and increased mortality. The coexistence of sarcopenia with obesity, termed ‘sarcopenic obesity’, contributes to skeletal muscle insulin resistance and the development of type 2 diabetes, a disease prevalent with advancing age. Despite this knowledge, the mechanisms contributing to sarcopenic obesity remain poorly understood, preventing the development of targeted therapeutics. This article will discuss the clinical and physiological consequences of sarcopenic obesity and propose myostatin as a potential candidate contributing to this condition. A special emphasis will be placed on examining the role of myostatin signaling in impairing both skeletal muscle growth and insulin signaling. In addition, the role of myostatin in regulating muscle-to fat cross talk, further exacerbating metabolic dysfunction in the elderly, will be highlighted. Lastly, we discuss how this knowledge has implications for the design of myostatin-inhibitor clinical trials.


2020 ◽  
Vol 98 (Supplement_4) ◽  
pp. 334-334
Author(s):  
Zhi-wen Song ◽  
Cheng-long Jin ◽  
Mao Ye ◽  
Chun-qi Gao ◽  
Hui-chao Yan ◽  
...  

Abstract Apoptosis is programmed cell death that can be stimulated by external stress or nutrition restrictions. Lysine (Lys) is an essential amino acid for pig growth, and the relationship between Lys deficiency caused apoptosis and inhibition of skeletal muscle growth remains unknown. The objective of this study was to investigate whether apoptosis could be regulated by Lys supplementation and the potential mechanism. In current work, 30 male Duroc × Landrace × Large weaned piglets were divided randomly into 3 groups: control group (Lys 1.30%), Lys deficiency group (Lys 0.86%), and Lys rescue group (Lys 0.86%, 0-14d; 1.30%,15–28 d). The experiment lasted for 28 days, and on the morning of 29 d, piglets were slaughtered to collect samples. Isobaric tag for relative and absolute quantification (iTRAQ) proteomics analysis of the longissimus dorsi muscle showed that Janus family tyrosine kinase (JAK)-signal transducer and activator of transcription (STAT) pathway was involved in Lys deficiency-induced apoptosis and inhibited skeletal muscle growth. Meanwhile, western blotting results of the longissimus dorsi muscle demonstrated that Lys deficiency caused apoptosis (P &lt; 0.05) with the JAK2-STAT3 pathway inhibition (P &lt; 0.05). Interestingly, apoptosis was suppressed (P &lt; 0.05), and the JAK2-STAT3 pathway was reactivated (P &lt; 0.05) after Lys re-supplementation in longissimus dorsi muscle. In addition, results of satellite cells (SCs) isolated from the longissimus dorsi muscle of 5-day-old Landrace piglets showed that Lys deficiency-induced apoptosis (P &lt; 0.05) was mediated by the JAK2-STAT3 pathway inhibition (P &lt; 0.05). Moreover, the JAK2-STAT3 pathway was reactivated (P &lt; 0.05) by Lys re-supplementation and suppressed apoptosis in SCs (P &lt; 0.05), and this effect was blocked (P &lt; 0.05) after SCs treated with AG-490 (a specific inhibitor of JAK2). Collectively, Lys inhibited apoptosis in SCs to govern skeletal muscle growth via the JAK2-STAT3 pathway.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Lin Kang ◽  
Pengtao Li ◽  
Danyang Wang ◽  
Taihao Wang ◽  
Dong Hao ◽  
...  

Abstract16S rRNA sequencing of human fecal samples has been tremendously successful in identifying microbiome changes associated with both aging and disease. A number of studies have described microbial alterations corresponding to physical frailty and nursing home residence among aging individuals. A gut-muscle axis through which the microbiome influences skeletal muscle growth/function has been hypothesized. However, the microbiome has yet to be examined in sarcopenia. Here, we collected fecal samples of 60 healthy controls (CON) and 27 sarcopenic (Case)/possibly sarcopenic (preCase) individuals and analyzed the intestinal microbiota using 16S rRNA sequencing. We observed an overall reduction in microbial diversity in Case and preCase samples. The genera Lachnospira, Fusicantenibacter, Roseburia, Eubacterium, and Lachnoclostridium—known butyrate producers—were significantly less abundant in Case and preCase subjects while Lactobacillus was more abundant. Functional pathways underrepresented in Case subjects included numerous transporters and phenylalanine, tyrosine, and tryptophan biosynthesis suggesting that protein processing and nutrient transport may be impaired. In contrast, lipopolysaccharide biosynthesis was overrepresented in Case and PreCase subjects suggesting that sarcopenia is associated with a pro-inflammatory metagenome. These analyses demonstrate structural and functional alterations in the intestinal microbiota that may contribute to loss of skeletal muscle mass and function in sarcopenia.


2016 ◽  
Vol 36 (1) ◽  
pp. 129-156 ◽  
Author(s):  
Brandon J.F. Gheller ◽  
Emily S. Riddle ◽  
Melinda R. Lem ◽  
Anna E. Thalacker-Mercer

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