scholarly journals The Regulatory Roles of PPARs in Skeletal Muscle Fuel Metabolism and Inflammation: Impact of PPAR Agonism on Muscle in Chronic Disease, Contraction and Sepsis

2021 ◽  
Vol 22 (18) ◽  
pp. 9775
Author(s):  
Hannah Crossland ◽  
Dumitru Constantin-Teodosiu ◽  
Paul L. Greenhaff
Keyword(s):  
Skeletal Muscle ◽  
Energy Homeostasis ◽  
Contractile Function ◽  
Muscle Protein ◽  
Lipid Lowering ◽  
Peroxisome Proliferator ◽  
Skeletal Muscle Protein ◽  
Comprehensive Overview ◽  
Fuel Metabolism ◽  
The Impact

The peroxisome proliferator-activated receptor (PPAR) family of transcription factors has been demonstrated to play critical roles in regulating fuel selection, energy expenditure and inflammation in skeletal muscle and other tissues. Activation of PPARs, through endogenous fatty acids and fatty acid metabolites or synthetic compounds, has been demonstrated to have lipid-lowering and anti-diabetic actions. This review will aim to provide a comprehensive overview of the functions of PPARs in energy homeostasis, with a focus on the impacts of PPAR agonism on muscle metabolism and function. The dysregulation of energy homeostasis in skeletal muscle is a frequent underlying characteristic of inflammation-related conditions such as sepsis. However, the potential benefits of PPAR agonism on skeletal muscle protein and fuel metabolism under these conditions remains under-investigated and is an area of research opportunity. Thus, the effects of PPARγ agonism on muscle inflammation and protein and carbohydrate metabolism will be highlighted, particularly with its potential relevance in sepsis-related metabolic dysfunction. The impact of PPARδ agonism on muscle mitochondrial function, substrate metabolism and contractile function will also be described.

scholarly journals Role of gp130 in basal and exercise-trained skeletal muscle mitochondrial quality control

2018 ◽  
Vol 124 (6) ◽  
pp. 1456-1470 ◽  
Author(s):  
Dennis K. Fix ◽  
Justin P. Hardee ◽  
Song Gao ◽  
Brandon N. VanderVeen ◽  
Kandy T. Velázquez ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Quality Control ◽  
Exercise Training ◽  
Intracellular Signaling ◽  
Metabolic Response ◽  
Muscle Protein ◽  
Mitochondrial Dynamics ◽  
Peroxisome Proliferator ◽  
Skeletal Muscle Protein ◽  
Mitochondrial Quality Control

The IL-6 cytokine family activates intracellular signaling pathways through glycoprotein-130 (gp130), and this signaling has established regulatory roles in muscle glucose metabolism and proteostasis. Although the IL-6 family has been implicated as myokines regulating the muscles’ metabolic response to exercise, gp130’s role in mitochondrial quality control involving fission, fusion, mitophagy, and biogenesis is not well understood. Therefore, we examined gp130’s role in basal and exercise-trained muscle mitochondrial quality control. Muscles from C57BL/6, skeletal muscle-specific gp130 knockout (KO) mice, and C2C12 myotubes, were examined. KO did not alter treadmill run-to-fatigue or indices of mitochondrial content [cytochrome- c oxidase (COX) activity] or biogenesis (AMPK, peroxisome proliferator-activated receptor-γ coactivator-1α, mitochondrial transcription factor A, and COX IV). KO increased mitochondrial fission 1 protein (FIS-1) while suppressing mitofusin-1 (MFN-1), which was recapitulated in myotubes after gp130 knockdown. KO induced ubiquitin-binding protein p62, Parkin, and ubiquitin in isolated mitochondria from gastrocnemius muscles. Knockdown of gp130 in myotubes suppressed STAT3 and induced accumulation of microtubule-associated protein-1 light chain 3B (LC3)-II relative to LC3-I. Suppression of myotube STAT3 did not alter FIS-1 or MFN-1. Exercise training increased muscle gp130 and suppressed STAT3. KO did not alter the exercise-training induction of COX activity, biogenesis, FIS-1, or Beclin-1. KO increased MFN-1 and suppressed 4-hydroxynonenal after exercise training. These findings suggest a role for gp130 in the modulation of mitochondrial dynamics and autophagic processes. NEW & NOTEWORTHY Although the IL-6 family of cytokines has been implicated in the regulation of skeletal muscle protein turnover and metabolism, less is understood about its role in mitochondrial quality control. We examined the glycoprotein-130 receptor in the regulation of skeletal muscle mitochondria quality control in the basal and exercise-trained states. We report that the muscle glycoprotein-130 receptor modulates basal mitochondrial dynamics and autophagic processes and is not necessary for exercise-training mitochondrial adaptations to quality control.

scholarly journals Dysregulation of skeletal muscle protein metabolism by alcohol

2015 ◽  
Vol 308 (9) ◽  
pp. E699-E712 ◽  
Author(s):  
Jennifer L. Steiner ◽  
Charles H. Lang
Keyword(s):  
Skeletal Muscle ◽  
Protein Synthesis ◽  
Protein Interactions ◽  
Contractile Function ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Developed Countries ◽  
Acute Intoxication ◽  
Future Research ◽  
Skeletal Muscle Protein

Alcohol abuse, either by acute intoxication or prolonged excessive consumption, leads to pathological changes in many organs and tissues including skeletal muscle. As muscle protein serves not only a contractile function but also as a metabolic reserve for amino acids, which are used to support the energy needs of other tissues, its content is tightly regulated and dynamic. This review focuses on the etiology by which alcohol perturbs skeletal muscle protein balance and thereby over time produces muscle wasting and weakness. The preponderance of data suggest that alcohol primarily impairs global protein synthesis, under basal conditions as well as in response to several anabolic stimuli including growth factors, nutrients, and muscle contraction. This inhibitory effect of alcohol is mediated, at least in part, by a reduction in mTOR kinase activity via a mechanism that remains poorly defined but likely involves altered protein-protein interactions within mTOR complex 1. Furthermore, alcohol can exacerbate the decrement in mTOR and/or muscle protein synthesis present in other catabolic states. In contrast, alcohol-induced changes in muscle protein degradation, either global or via specific modulation of the ubiquitin-proteasome or autophagy pathways, are relatively inconsistent and may be model dependent. Herein, changes produced by acute intoxication versus chronic ingestion are contrasted in relation to skeletal muscle metabolism, and limitations as well as opportunities for future research are discussed. As the proportion of more economically developed countries ages and chronic illness becomes more prevalent, a better understanding of the etiology of biomedical consequences of alcohol use disorders is warranted.

scholarly journals Mechanisms Involved in 3′,5′-Cyclic Adenosine Monophosphate-Mediated Inhibition of the Ubiquitin-Proteasome System in Skeletal Muscle

Endocrinology ◽  
2009 ◽  
Vol 150 (12) ◽  
pp. 5395-5404 ◽  
Author(s):  
Dawit A. P. Gonçalves ◽  
Eduardo C. Lira ◽  
Amanda M. Baviera ◽  
Peirang Cao ◽  
Neusa M. Zanon ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Knockout Mice ◽  
Muscle Protein ◽  
Phosphodiesterase Inhibitor ◽  
Ubiquitin Proteasome System ◽  
Peroxisome Proliferator ◽  
Skeletal Muscle Protein ◽  
Camp Phosphodiesterase ◽  
Ubiquitin Proteasome ◽  
Β2 Agonist

Abstract Although it is well known that catecholamines inhibit skeletal muscle protein degradation, the molecular underlying mechanism remains unclear. This study was undertaken to investigate the role of β2-adrenoceptors (AR) and cAMP in regulating the ubiquitin-proteasome system (UPS) in skeletal muscle. We report that increased levels of cAMP in isolated muscles, promoted by the cAMP phosphodiesterase inhibitor isobutylmethylxanthine was accompanied by decreased activity of the UPS, levels of ubiquitin-protein conjugates, and expression of atrogin-1, a key ubiquitin-protein ligase involved in muscle atrophy. In cultured myotubes, atrogin-1 induction after dexamethasone treatment was completely prevented by isobutylmethylxanthine. Furthermore, administration of clenbuterol, a selective β2-agonist, to mice increased muscle cAMP levels and suppressed the fasting-induced expression of atrogin-1 and MuRF-1, atrogin-1 mRNA being much more responsive to clenbuterol. Moreover, clenbuterol increased the phosphorylation of muscle Akt and Foxo3a in fasted rats. Similar responses were observed in muscles exposed to dibutyryl-cAMP. The stimulatory effect of clenbuterol on cAMP and Akt was abolished in muscles from β2-AR knockout mice. The suppressive effect of β2-agonist on atrogin-1 was not mediated by PGC-1α (peroxisome proliferator-activated receptor-γ coactivator 1α known to be induced by β2-agonists and previously shown to inhibit atrogin-1 expression), because food-deprived PGC-1α knockout mice were still sensitive to clenbuterol. These findings suggest that the cAMP increase induced by stimulation of β2-AR in skeletal muscles from fasted mice is possibly the mechanism by which catecholamines suppress atrogin-1 and the UPS, this effect being mediated via phosphorylation of Akt and thus inactivation of Foxo3.

scholarly journals The Impact of Anthocyanins and Iridoids on Transcription Factors Crucial for Lipid and Cholesterol Homeostasis

2021 ◽  
Vol 22 (11) ◽  
pp. 6074
Author(s):  
Maciej Danielewski ◽  
Agnieszka Matuszewska ◽  
Adam Szeląg ◽  
Tomasz Sozański
Keyword(s):  
Transcription Factors ◽  
Cholesterol Metabolism ◽  
Binding Protein ◽  
Regulatory Element ◽  
Cholesterol Homeostasis ◽  
Lipid Lowering ◽  
Peroxisome Proliferator ◽  
Peroxisome Proliferator Activated Receptor ◽  
Cell Functions ◽  
The Impact

Nutrition determines our health, both directly and indirectly. Consumed foods affect the functioning of individual organs as well as entire systems, e.g., the cardiovascular system. There are many different diets, but universal guidelines for proper nutrition are provided in the WHO healthy eating pyramid. According to the latest version, plant products should form the basis of our diet. Many groups of plant compounds with a beneficial effect on human health have been described. Such groups include anthocyanins and iridoids, for which it has been proven that their consumption may lead to, inter alia, antioxidant, cholesterol and lipid-lowering, anti-obesity and anti-diabetic effects. Transcription factors directly affect a number of parameters of cell functions and cellular metabolism. In the context of lipid and cholesterol metabolism, five particularly important transcription factors can be distinguished: liver X receptor (LXR), peroxisome proliferator-activated receptor-α (PPAR-α), peroxisome proliferator-activated receptor-γ (PPAR-γ), CCAAT/enhancer binding protein α (C/EBPα) and sterol regulatory element-binding protein 1c (SREBP-1c). Both anthocyanins and iridoids may alter the expression of these transcription factors. The aim of this review is to collect and systematize knowledge about the impact of anthocyanins and iridoids on transcription factors crucial for lipid and cholesterol homeostasis.

Development of Skeletal Muscle Protein

Nature ◽  
1958 ◽  
Vol 182 (4645) ◽  
pp. 1312-1313 ◽  
Author(s):  
YOSHITO OGAWA
Keyword(s):  
Skeletal Muscle ◽  
Muscle Protein ◽  
Skeletal Muscle Protein

scholarly journals Biochemical approaches for nutritional support of skeletal muscle protein metabolism during sepsis

2004 ◽  
Vol 17 (1) ◽  
pp. 77-88 ◽  
Author(s):  
Thomas C. Vary ◽  
Christopher J. Lynch
Keyword(s):  
Skeletal Muscle ◽  
Amino Acids ◽  
Metabolic Response ◽  
Muscle Protein ◽  
The Body ◽  
Integrated Analysis ◽  
Skeletal Muscle Protein ◽  
Catabolic State ◽  
N Metabolism ◽  
Induced Defects

Sepsis initiates a unique series of modifications in the homeostasis of N metabolism and profoundly alters the integration of inter-organ cooperatively in the overall N and energy economy of the host. The net effect of these alterations is an overall N catabolic state, which seriously compromises recovery and is semi-refractory to treatment with current therapies. These alterations lead to a functional redistribution of N (amino acids and proteins) and substrate metabolism among injured tissues and major body organs. The redistribution of amino acids and proteins results in a quantitative reordering of the usual pathways of C and N flow within and among regions of the body with a resultant depletion of the required substrates and cofactors in important organs. The metabolic response to sepsis is a highly integrated, complex series of reactions. To understand the regulation of the response to sepsis, a comprehensive, integrated analysis of the fundamental physiological relationships of key metabolic pathways and mechanisms in sepsis is essential. The catabolism of skeletal muscles, which is manifested by an increase in protein degradation and a decrease in synthesis, persists despite state-of-the-art nutritional care. Much effort has focused on the modulation of the overall amount of nutrients given to septic patients in a hope to improve efficiencies in utilisation and N economies, rather than the support of specific end-organ targets. The present review examines current understanding of the processes affected by sepsis and testable means to circumvent the sepsis-induced defects in protein synthesis in skeletal muscle through increasing provision of amino acids (leucine, glutamine, or arginine) that in turn act as nutrient signals to regulate a number of cellular processes.

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