The Role of Amino Acids in Skeletal Muscle Adaptation to Exercise

2013 ◽  
pp. 85-102 ◽  
Author(s):  
Nick Aguirre ◽  
Luc J.C. van Loon ◽  
Keith Baar
Keyword(s):  
Skeletal Muscle ◽  
Amino Acids ◽  
Muscle Adaptation ◽  
Adaptation To Exercise

scholarly journals The Recent Understanding of the Neurotrophin's Role in Skeletal Muscle Adaptation

2011 ◽  
Vol 2011 ◽  
pp. 1-12 ◽  
Author(s):  
Kunihiro Sakuma ◽  
Akihiko Yamaguchi
Keyword(s):  
Skeletal Muscle ◽  
Neuromuscular Disorders ◽  
Muscle Fibers ◽  
Brain Disorders ◽  
Muscle Adaptation ◽  
Bdnf Mrna ◽  
Pathological Conditions ◽  
Development And Differentiation ◽  
And Function

This paper summarizes the various effects of neurotrophins in skeletal muscle and how these proteins act as potential regulators of the maintenance, function, and regeneration of skeletal muscle fibers. Increasing evidence suggests that this family of neurotrophic factors influence not only the survival and function of innervating motoneurons but also the development and differentiation of myoblasts and muscle fibers. Muscle contractions (e.g., exercise) produce BDNF mRNA and protein in skeletal muscle, and the BDNF seems to play a role in enhancing glucose metabolism and may act for myokine to improve various brain disorders (e.g., Alzheimer's disease and major depression). In adults with neuromuscular disorders, variations in neurotrophin expression are found, and the role of neurotrophins under such conditions is beginning to be elucidated. This paper provides a basis for a better understanding of the role of these factors under such pathological conditions and for treatment of human neuromuscular disease.

From skeletal muscle damage and regeneration to the hypertrophy induced by exercise: What is the role of different macrophages subsets?

2021 ◽  
Author(s):  
André Luis Araujo Minari ◽  
Ronaldo V. Thomatieli-Santos
Keyword(s):  
Skeletal Muscle ◽  
Muscle Damage ◽  
Muscle Adaptation ◽  
Muscle Recovery ◽  
Skeletal Muscle Damage ◽  
Know How ◽  
Tissue Healing ◽  
Macrophage Subsets

Macrophages are one of the top players when considering immune cells involved with tissue homeostasis. Recently, increasing evidence has demonstrated that these macrophages could also present two major subsets during tissue healing; proliferative macrophages (M1-like), which are responsible for increasing myogenic cell proliferation, and restorative macrophages (M2-like), which are accountable for the end of the mature muscle myogenesis. The participation and characterization of these macrophage subsets is critical during myogenesis, not only to understand the inflammatory role of macrophages during muscle recovery but also to create supportive strategies that can improve mass muscle maintenance. Indeed, most of our knowledge about macrophage subsets comes from skeletal muscle damage protocols, and we still do not know how these subsets can contribute to skeletal muscle adaptation. This narrative review aims to collect and discuss studies demonstrating the involvement of different macrophage subsets during the skeletal muscle damage/regeneration process, showcasing an essential role of these macrophage subsets during muscle adaptation induced by acute and chronic exercise programs.

Catabolism and synthesis of amino acids in skeletal muscle: their significance in monogastric mammals and ruminants

1993 ◽  
Vol 44 (3) ◽  
pp. 443 ◽  
Author(s):  
E Teleni
Keyword(s):  
Skeletal Muscle ◽  
Amino Acids ◽  
Significant Activity ◽  
Acid Base Balance ◽  
Carbon And Nitrogen ◽  
Specific Effects ◽  
Protein Energy ◽  
Base Balance ◽  
Lower Carbon

The enhanced rate of synthesis and catabolism of amino acids in, and their release from, skeletal muscle, particularly during fasting, exercise and metabolic acidosis, highlight the integrative role of muscle in protein-energy metabolism. This review discusses aspects of such changes in muscles of monogastric mammals and ruminants. The glucose-alanine cycle, as it was originally proposed, has been well substantiated by studies using human and rat muscles. An alternative proposal, which suggested that other amino acids make a major contribution to the carbon skeleton of alanine synthesized in muscle, is less convincing, since some of the inhibitors and substrates used in relevant studies have been demonstrated to have multiple rather than specific effects. In the ruminant, the glucose-alanine cycle is quantitatively less significant than in human. The probable reason for this difference is the limited available pyruvate in ruminant muscle for transamination to alanine. This may be due to a lower carbon flux through the glycolytic pathway and/or to significant activity of the anaplerotic enzyme, pyruvate carboxylase. It is suggested that glutamine is the more important carrier of carbon and nitrogen out of skeletal muscle and that alanine may serve only as an ancillary vehicle to transport carbon and nitrogen when the availability of pyruvate for transamination in muscle is high. The more diverse role of glutamine (cf. alanine) in acid-base balance, as a respiratory fuel in the cells of the immune system and the epithelia of the small intestine, where it may also be converted to alanine for subsequent gluconeogenesis in the liver, is consistent with this suggestion.

scholarly journals Emerging role of extracellular vesicles in the regulation of skeletal muscle adaptation

2019 ◽  
Vol 127 (2) ◽  
pp. 645-653 ◽  
Author(s):  
Ivan J. Vechetti
Keyword(s):  
Skeletal Muscle ◽  
Extracellular Vesicles ◽  
Human Body ◽  
Intercellular Communication ◽  
Skeletal Muscle Mass ◽  
Genetic Material ◽  
Muscle Adaptation ◽  
Pathological Conditions ◽  
Isolation Methods

Extracellular vesicles (EVs) were initially characterized as “garbage bags” with the purpose of removing unwanted material from cells. It is now becoming clear that EVs mediate intercellular communication between distant cells through a transfer of genetic material, a process important to the systemic adaptation in physiological and pathological conditions. Although speculative, it has been suggested that the majority of EVs that make it into the bloodstream would be coming from skeletal muscle, since it is one of the largest organs in the human body. Although it is well established that skeletal muscle secretes peptides (currently known as myokines) into the bloodstream, the notion that skeletal muscle releases EVs is in its infancy. Besides intercellular communication and systemic adaptation, EV release could represent the mechanism by which muscle adapts to certain stimuli. This review summarizes the current understanding of EV biology and biogenesis and current isolation methods and briefly discusses the possible role EVs have in regulating skeletal muscle mass.

scholarly journals Satellite Cell Depletion Disrupts Transcriptional Coordination and Muscle Adaptation to Exercise

Function ◽  
2020 ◽  
Vol 2 (1) ◽  
Author(s):  
Davis A Englund ◽  
Vandré C Figueiredo ◽  
Cory M Dungan ◽  
Kevin A Murach ◽  
Bailey D Peck ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Satellite Cell ◽  
Satellite Cells ◽  
Gene Networks ◽  
Wheel Running ◽  
Skeletal Muscle Regeneration ◽  
Rna Seq ◽  
Muscle Adaptation ◽  
Hypertrophic Growth ◽  
Adaptation To Exercise

Abstract Satellite cells are required for postnatal development, skeletal muscle regeneration across the lifespan, and skeletal muscle hypertrophy prior to maturity. Our group has aimed to address whether satellite cells are required for hypertrophic growth in mature skeletal muscle. Here, we generated a comprehensive characterization and transcriptome-wide profiling of skeletal muscle during adaptation to exercise in the presence or absence of satellite cells in order to identify distinct phenotypes and gene networks influenced by satellite cell content. We administered vehicle or tamoxifen to adult Pax7-DTA mice and subjected them to progressive weighted wheel running (PoWeR). We then performed immunohistochemical analysis and whole-muscle RNA-seq of vehicle (SC+) and tamoxifen-treated (SC−) mice. Further, we performed single myonuclear RNA-seq to provide detailed information on how satellite cell fusion affects myonuclear transcription. We show that while skeletal muscle can mount a robust hypertrophic response to PoWeR in the absence of satellite cells, growth, and adaptation are ultimately blunted. Transcriptional profiling reveals several gene networks key to muscle adaptation are altered in the absence of satellite cells.

scholarly journals The Role of Skeletal Muscle in The Pathogenesis of Altered Concentrations of Branched-Chain Amino Acids (Valine, Leucine, and Isoleucine) in Liver Cirrhosis, Diabetes, and Other Diseases

2021 ◽  
pp. 293-305
Author(s):  
M Holeček
Keyword(s):  
Skeletal Muscle ◽  
Amino Acids ◽  
Liver Cirrhosis ◽  
Fatty Acid ◽  
Fatty Acid Oxidation ◽  
Branched Chain Amino Acids ◽  
Acid Oxidation ◽  
Amino Group ◽  
Branched Chain

The article shows that skeletal muscle plays a dominant role in the catabolism of branched-chain amino acids (BCAAs; valine, leucine, and isoleucine) and the pathogenesis of their decreased concentrations in liver cirrhosis, increased concentrations in diabetes, and nonspecific alterations in disorders with signs of systemic inflammatory response syndrome (SIRS), such as burn injury and sepsis. The main role of skeletal muscle in BCAA catabolism is due to its mass and high activity of BCAA aminotransferase, which is absent in the liver. Decreased BCAA levels in liver cirrhosis are due to increased use of the BCAA as a donor of amino group to α-ketoglutarate for synthesis of glutamate, which in muscles acts as a substrate for ammonia detoxification to glutamine. Increased BCAA levels in diabetes are due to alterations in glycolysis, citric acid cycle, and fatty acid oxidation. Decreased glycolysis and citric cycle activity impair BCAA transamination to branched-chain keto acids (BCKAs) due to decreased supply of amino group acceptors (α-ketoglutarate, pyruvate, and oxaloacetate); increased fatty acid oxidation inhibits flux of BCKA through BCKA dehydrogenase due to increased supply of NADH and acyl-CoAs. Alterations in BCAA levels in disorders with SIRS are inconsistent due to contradictory effects of SIRS on muscles. Specifically, increased proteolysis and insulin resistance tend to increase BCAA levels, whereas activation of BCKA dehydrogenase and glutamine synthesis tend to decrease BCAA levels. The studies are needed to elucidate the role of alterations in BCAA metabolism and the effects of BCAA supplementation on the outcomes of specific diseases.

Skeletal Muscle Adaptation to Exercise

Muscle ◽  
2012 ◽  
pp. 911-920 ◽  
Author(s):  
John J. McCarthy ◽  
Karyn A. Esser
Keyword(s):  
Skeletal Muscle ◽  
Muscle Adaptation ◽  
Adaptation To Exercise

scholarly journals More than just a garbage can: emerging roles of the lysosome as an anabolic organelle in skeletal muscle

2020 ◽  
Vol 319 (3) ◽  
pp. C561-C568
Author(s):  
Sidney Abou Sawan ◽  
Michael Mazzulla ◽  
Daniel R. Moore ◽  
Nathan Hodson
Keyword(s):  
Skeletal Muscle ◽  
Amino Acids ◽  
Intracellular Signaling ◽  
Muscle Protein ◽  
Future Research ◽  
Dietary Amino Acids ◽  
Lysosome Biogenesis ◽  
Transcription Factor Eb ◽  
Mtorc1 Activation

Skeletal muscle is a highly plastic tissue capable of remodeling in response to a range of physiological stimuli, including nutrients and exercise. Historically, the lysosome has been considered an essentially catabolic organelle contributing to autophagy, phagocytosis, and exo-/endocytosis in skeletal muscle. However, recent evidence has emerged of several anabolic roles for the lysosome, including the requirement for autophagy in skeletal muscle mass maintenance, the discovery of the lysosome as an intracellular signaling hub for mechanistic target of rapamycin complex 1 (mTORC1) activation, and the importance of transcription factor EB/lysosomal biogenesis-related signaling in the regulation of mTORC1-mediated protein synthesis. We, therefore, propose that the lysosome is an understudied organelle with the potential to underpin the skeletal muscle adaptive response to anabolic stimuli. Within this review, we describe the molecular regulation of lysosome biogenesis and detail the emerging anabolic roles of the lysosome in skeletal muscle with particular emphasis on how these roles may mediate adaptations to chronic resistance exercise. Furthermore, given the well-established role of amino acids to support muscle protein remodeling, we describe how dietary proteins “labeled” with stable isotopes could provide a complementary research tool to better understand how lysosomal biogenesis, autophagy regulation, and/or mTORC1-lysosomal repositioning can mediate the intracellular usage of dietary amino acids in response to anabolic stimuli. Finally, we provide avenues for future research with the aim of elucidating how the regulation of this important organelle could mediate skeletal muscle anabolism.

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