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Smiles WJ, Ovens AJ, Oakhill JS, Kofler B. The metabolic sensor AMPK: Twelve enzymes in one. Mol Metab 2024; 90:102042. [PMID: 39362600 DOI: 10.1016/j.molmet.2024.102042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/02/2024] [Revised: 09/12/2024] [Accepted: 09/27/2024] [Indexed: 10/05/2024] Open
Abstract
BACKGROUND AMP-activated protein kinase (AMPK) is an evolutionarily conserved regulator of energy metabolism. AMPK is sensitive to acute perturbations to cellular energy status and leverages fundamental bioenergetic pathways to maintain cellular homeostasis. AMPK is a heterotrimer comprised of αβγ-subunits that in humans are encoded by seven individual genes (isoforms α1, α2, β1, β2, γ1, γ2 and γ3), permitting formation of at least 12 different complexes with personalised biochemical fingerprints and tissue expression patterns. While the canonical activation mechanisms of AMPK are well-defined, delineation of subtle, as well as substantial, differences in the regulation of heterogenous AMPK complexes remain poorly defined. SCOPE OF REVIEW Here, taking advantage of multidisciplinary findings, we dissect the many aspects of isoform-specific AMPK function and links to health and disease. These include, but are not limited to, allosteric activation by adenine nucleotides and small molecules, co-translational myristoylation and post-translational modifications (particularly phosphorylation), governance of subcellular localisation, and control of transcriptional networks. Finally, we delve into current debate over whether AMPK can form novel protein complexes (e.g., dimers lacking the α-subunit), altogether highlighting opportunities for future and impactful research. MAJOR CONCLUSIONS Baseline activity of α1-AMPK is higher than its α2 counterpart and is more sensitive to synergistic allosteric activation by metabolites and small molecules. α2 complexes however, show a greater response to energy stress (i.e., AMP production) and appear to be better substrates for LKB1 and mTORC1 upstream. These differences may explain to some extent why in certain cancers α1 is a tumour promoter and α2 a suppressor. β1-AMPK activity is toggled by a 'myristoyl-switch' mechanism that likely precedes a series of signalling events culminating in phosphorylation by ULK1 and sensitisation to small molecules or endogenous ligands like fatty acids. β2-AMPK, not entirely beholden to this myristoyl-switch, has a greater propensity to infiltrate the nucleus, which we suspect contributes to its oncogenicity in some cancers. Last, the unique N-terminal extensions of the γ2 and γ3 isoforms are major regulatory domains of AMPK. mTORC1 may directly phosphorylate this region in γ2, although whether this is inhibitory, especially in disease states, is unclear. Conversely, γ3 complexes might be preferentially regulated by mTORC1 in response to physical exercise.
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Affiliation(s)
- William J Smiles
- Research Program for Receptor Biochemistry and Tumour Metabolism, Department of Paediatrics, University Hospital of the Paracelsus Medical University, Salzburg, Austria; Metabolic Signalling Laboratory, St. Vincent's Institute of Medical Research, Fitzroy, Melbourne, Australia.
| | - Ashley J Ovens
- Protein Engineering in Immunity & Metabolism, St. Vincent's Institute of Medical Research, Fitzroy, Melbourne, Australia
| | - Jonathan S Oakhill
- Metabolic Signalling Laboratory, St. Vincent's Institute of Medical Research, Fitzroy, Melbourne, Australia; Department of Medicine, University of Melbourne, Parkville, Australia
| | - Barbara Kofler
- Research Program for Receptor Biochemistry and Tumour Metabolism, Department of Paediatrics, University Hospital of the Paracelsus Medical University, Salzburg, Austria
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Ren Y, Sun J, Mao X. Quality changes in gazami crab (Portunus trituberculatus) during refrigeration. Food Chem 2024; 437:137942. [PMID: 37951080 DOI: 10.1016/j.foodchem.2023.137942] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2023] [Revised: 11/02/2023] [Accepted: 11/04/2023] [Indexed: 11/13/2023]
Abstract
Gazami crab (Portunus trituberculatus) is prone to spoilage during storage and transportation. More research is needed to determine how to reliably show its freshness and explain the mechanism of quality deterioration. We hypothesized that proteins extracted from crabs can be biomarkers to detect crab muscle quality changes. This work used physicochemical and proteomic approaches to investigate protein biomarkers and molecular mechanisms driving changes in gazami crab muscle quality after long-term refrigeration. It was shown that 66 differentially abundant proteins (DAPs) were closely associated with pH and texture and can be used as biomarkers to assess crab muscle freshness. According to bioinformatics studies, ribosomes and autophagy were significant mechanisms in crab rotting. These findings provided new concepts and a theoretical foundation for evaluating the freshness of refrigerated gazami crab and help uncover the molecular mechanism of its quality deterioration.
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Affiliation(s)
- Yanmei Ren
- State Key Laboratory of Marine Food Processing and Safety Control, College of Food Science and Engineering, Ocean University of China, Qingdao 266404, PR China; Qingdao Key Laboratory of Food Biotechnology, Qingdao 266404, PR China; Key Laboratory of Biological Processing of Aquatic Products, China National Light Industry, Qingdao 266404, PR China
| | - Jianan Sun
- State Key Laboratory of Marine Food Processing and Safety Control, College of Food Science and Engineering, Ocean University of China, Qingdao 266404, PR China; Qingdao Key Laboratory of Food Biotechnology, Qingdao 266404, PR China; Key Laboratory of Biological Processing of Aquatic Products, China National Light Industry, Qingdao 266404, PR China.
| | - Xiangzhao Mao
- State Key Laboratory of Marine Food Processing and Safety Control, College of Food Science and Engineering, Ocean University of China, Qingdao 266404, PR China; Laboratory for Marine Drugs and Bioproducts of Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, PR China; Qingdao Key Laboratory of Food Biotechnology, Qingdao 266404, PR China; Key Laboratory of Biological Processing of Aquatic Products, China National Light Industry, Qingdao 266404, PR China.
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3
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Vertyshev AY, Akberdin IR, Kolpakov FA. Numerous Trigger-like Interactions of Kinases/Protein Phosphatases in Human Skeletal Muscles Can Underlie Transient Processes in Activation of Signaling Pathways during Exercise. Int J Mol Sci 2023; 24:11223. [PMID: 37446402 DOI: 10.3390/ijms241311223] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Revised: 07/03/2023] [Accepted: 07/05/2023] [Indexed: 07/15/2023] Open
Abstract
Optimizing physical training regimens to increase muscle aerobic capacity requires an understanding of the internal processes that occur during exercise that initiate subsequent adaptation. During exercise, muscle cells undergo a series of metabolic events that trigger downstream signaling pathways and induce the expression of many genes in working muscle fibers. There are a number of studies that show the dependence of changes in the activity of AMP-activated protein kinase (AMPK), one of the mediators of cellular signaling pathways, on the duration and intensity of single exercises. The activity of various AMPK isoforms can change in different directions, increasing for some isoforms and decreasing for others, depending on the intensity and duration of the load. This review summarizes research data on changes in the activity of AMPK, Ca2+/calmodulin-dependent protein kinase II (CaMKII), and other components of the signaling pathways in skeletal muscles during exercise. Based on these data, we hypothesize that the observed changes in AMPK activity may be largely related to metabolic and signaling transients rather than exercise intensity per se. Probably, the main events associated with these transients occur at the beginning of the exercise in a time window of about 1-10 min. We hypothesize that these transients may be partly due to putative trigger-like kinase/protein phosphatase interactions regulated by feedback loops. In addition, numerous dynamically changing factors, such as [Ca2+], metabolite concentration, and reactive oxygen and nitrogen species (RONS), can shift the switching thresholds and change the states of these triggers, thereby affecting the activity of kinases (in particular, AMPK and CaMKII) and phosphatases. The review considers the putative molecular mechanisms underlying trigger-like interactions. The proposed hypothesis allows for a reinterpretation of the experimental data available in the literature as well as the generation of ideas to optimize future training regimens.
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Affiliation(s)
| | - Ilya R Akberdin
- Department of Computational Biology, Scientific Center for Information Technologies and Artificial Intelligence, Sirius University of Science and Technology, 354340 Sochi, Russia
- Biosoft.Ru, Ltd., 630058 Novosibirsk, Russia
- Department of Natural Sciences, Novosibirsk State University, 630090 Novosibirsk, Russia
| | - Fedor A Kolpakov
- Department of Computational Biology, Scientific Center for Information Technologies and Artificial Intelligence, Sirius University of Science and Technology, 354340 Sochi, Russia
- Biosoft.Ru, Ltd., 630058 Novosibirsk, Russia
- Federal Research Center for Information and Computational Technologies, 630090 Novosibirsk, Russia
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4
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Jakobsgaard JE, de Paoli F, Vissing K. Protein signaling in response to ex vivo dynamic contractions is independent of training status in rat skeletal muscle. Exp Physiol 2022; 107:919-932. [PMID: 35723680 PMCID: PMC9545705 DOI: 10.1113/ep090446] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Accepted: 06/16/2022] [Indexed: 11/24/2022]
Abstract
New Findings What is the central question of this study? Are myofibre protein signalling responses to ex vivo dynamic contractions altered by accustomization to voluntary endurance training in rats? What is the main finding and its importance? In response to ex vivo dynamic muscle contractions, canonical myofibre protein signalling pertaining to metabolic transcriptional regulation, as well as translation initiation and elongation, was not influenced by prior accustomization to voluntary endurance training in rats. Accordingly, intrinsic myofibre protein signalling responses to standardized contractile activity may be independent of prior exercise training in rat skeletal muscle.
Abstract Skeletal muscle training status may influence myofibre regulatory protein signalling in response to contractile activity. The current study employed a purpose‐designed ex vivo dynamic contractile protocol to evaluate the effect of exercise‐accustomization on canonical myofibre protein signalling for metabolic gene expression and for translation initiation and elongation. To this end, rats completed 8 weeks of in vivo voluntary running training versus no running control intervention, whereupon an ex vivo endurance‐type dynamic contraction stimulus was conducted in isolated soleus muscle preparations from both intervention groups. Protein signalling response by phosphorylation was evaluated by immunoblotting at 0 and 3 h following ex vivo stimulation. Phosphorylation of AMP‐activated protein kinase α‐isoforms and its downstream target, acetyl‐CoA carboxylase, as well as phosphorylation of eukaryotic elongation factor 2 (eEF2) was increased immediately following the dynamic contraction protocol (at 0 h). Signalling for translation initiation and elongation was evident at 3 h after dynamic contractile activity, as evidenced by increased phosphorylation of p70 S6 kinase and eukaryotic translation initiation factor 4E‐binding protein 1, as well as a decrease in phosphorylation of eEF2 back to resting control levels. However, prior exercise training did not alter phosphorylation responses of the investigated signalling proteins. Accordingly, protein signalling responses to standardized endurance‐type contractions may be independent of training status in rat muscle during ex vivo conditions. The present findings add to our current understanding of molecular regulatory events responsible for skeletal muscle plasticity.
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Affiliation(s)
- Jesper Emil Jakobsgaard
- Exercise Biology, Department of Public Health, Faculty of Health, Aarhus University, Denmark
| | - Frank de Paoli
- Department of Biomedicine, Faculty of Health, Aarhus University, Denmark
| | - Kristian Vissing
- Exercise Biology, Department of Public Health, Faculty of Health, Aarhus University, Denmark
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Rothschild JA, Islam H, Bishop DJ, Kilding AE, Stewart T, Plews DJ. Factors Influencing AMPK Activation During Cycling Exercise: A Pooled Analysis and Meta-Regression. Sports Med 2021; 52:1273-1294. [PMID: 34878641 DOI: 10.1007/s40279-021-01610-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/22/2021] [Indexed: 01/14/2023]
Abstract
BACKGROUND The 5' adenosine monophosphate (AMP)-activated protein kinase (AMPK) is a cellular energy sensor that is activated by increases in the cellular AMP/adenosine diphosphate:adenosine triphosphate (ADP:ATP) ratios and plays a key role in metabolic adaptations to endurance training. The degree of AMPK activation during exercise can be influenced by many factors that impact on cellular energetics, including exercise intensity, exercise duration, muscle glycogen, fitness level, and nutrient availability. However, the relative importance of these factors for inducing AMPK activation remains unclear, and robust relationships between exercise-related variables and indices of AMPK activation have not been established. OBJECTIVES The purpose of this analysis was to (1) investigate correlations between factors influencing AMPK activation and the magnitude of change in AMPK activity during cycling exercise, (2) investigate correlations between commonly reported measures of AMPK activation (AMPK-α2 activity, phosphorylated (p)-AMPK, and p-acetyl coenzyme A carboxylase (p-ACC), and (3) formulate linear regression models to determine the most important factors for AMPK activation during exercise. METHODS Data were pooled from 89 studies, including 982 participants (93.8% male, maximal oxygen consumption [[Formula: see text]] 51.9 ± 7.8 mL kg-1 min-1). Pearson's correlation analysis was performed to determine relationships between effect sizes for each of the primary outcome markers (AMPK-α2 activity, p-AMPK, p-ACC) and factors purported to influence AMPK signaling (muscle glycogen, carbohydrate ingestion, exercise duration and intensity, fitness level, and muscle metabolites). General linear mixed-effect models were used to examine which factors influenced AMPK activation. RESULTS Significant correlations (r = 0.19-0.55, p < .05) with AMPK activity were found between end-exercise muscle glycogen, exercise intensity, and muscle metabolites phosphocreatine, creatine, and free ADP. All markers of AMPK activation were significantly correlated, with the strongest relationship between AMPK-α2 activity and p-AMPK (r = 0.56, p < 0.001). The most important predictors of AMPK activation were the muscle metabolites and exercise intensity. CONCLUSION Muscle glycogen, fitness level, exercise intensity, and exercise duration each influence AMPK activity during exercise when all other factors are held constant. However, disrupting cellular energy charge is the most influential factor for AMPK activation during endurance exercise.
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Affiliation(s)
- Jeffrey A Rothschild
- Sports Performance Research Institute New Zealand (SPRINZ), Auckland University of Technology, Auckland, New Zealand.
| | - Hashim Islam
- School of Health and Exercise Sciences, University of British Columbia Okanagan, Kelowna, BC, Canada
| | - David J Bishop
- Institute for Health and Sport (iHeS), Victoria University, Melbourne, VIC, Australia.,School of Medical and Health Sciences, Edith Cowan University, Joondalup, WA, Australia
| | - Andrew E Kilding
- Sports Performance Research Institute New Zealand (SPRINZ), Auckland University of Technology, Auckland, New Zealand
| | - Tom Stewart
- Sports Performance Research Institute New Zealand (SPRINZ), Auckland University of Technology, Auckland, New Zealand
| | - Daniel J Plews
- Sports Performance Research Institute New Zealand (SPRINZ), Auckland University of Technology, Auckland, New Zealand
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Yamada T, Kimura I, Ashida Y, Tamai K, Fusagawa H, Tohse N, Westerblad H, Andersson DC, Sato T. Larger improvements in fatigue resistance and mitochondrial function with high- than with low-intensity contractions during interval training of mouse skeletal muscle. FASEB J 2021; 35:e21988. [PMID: 34665879 DOI: 10.1096/fj.202101204r] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2021] [Revised: 09/19/2021] [Accepted: 09/28/2021] [Indexed: 12/15/2022]
Abstract
Interval training (IT) results in improved fatigue resistance in skeletal muscle mainly due to an increased aerobic capacity, which involves increased muscle mitochondrial content and/or improved mitochondrial function. We hypothesized that IT with high-intensity contractions is more effective in increasing mitochondrial function, and hence fatigue resistance, than low-intensity contractions. To study this hypothesis without interference from differences in muscle fiber recruitment obliged to occur during voluntary contractions, IT was performed with in situ supramaximal electrical stimulation where all muscle fibers are recruited. We compared the effect of IT with repeated low-intensity (20 Hz stimulation, IT20) and high-intensity (100 Hz stimulation, IT100) contractions on fatigue resistance and mitochondrial content and function in mouse plantar flexor muscles. Muscles were stimulated every other day for 4 weeks. The averaged peak torque during IT bouts was 4.2-fold higher with IT100 than with IT20. Both stimulation protocols markedly improved in situ fatigue resistance, although the improvement was larger with IT100. The citrate synthase activity, a biomarker of mitochondrial content, was similarly increased with IT20 and IT100. Conversely, increased expression of mitochondrial respiratory chain (MRC) complexes I, III, and IV was only observed with IT100 and this was accompanied by increases in MRC supercomplex formation and pyruvate-malate-driven state 3 respiration in isolated mitochondria. In conclusion, the IT-induced increase in fatigue resistance is larger with high-intensity than with low-intensity contractions and this is linked to improved mitochondrial function due to increased expression of MRC complexes and assembly of MRC supercomplexes.
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Affiliation(s)
- Takashi Yamada
- Graduate School of Health Sciences, Sapporo Medical University, Sapporo, Japan
| | - Iori Kimura
- Graduate School of Health Sciences, Sapporo Medical University, Sapporo, Japan
| | - Yuki Ashida
- Graduate School of Health Sciences, Sapporo Medical University, Sapporo, Japan.,Japan Society for Promotion of Science, Tokyo, Japan
| | - Katsuyuki Tamai
- Graduate School of Health Sciences, Sapporo Medical University, Sapporo, Japan
| | - Hiroyori Fusagawa
- Department of Cellular Physiology and Signal Transduction, Sapporo Medical University School of Medicine, Sapporo, Japan.,Department of Orthopedic Surgery, Sapporo Medical University School of Medicine, Sapporo, Japan
| | - Noritsugu Tohse
- Department of Cellular Physiology and Signal Transduction, Sapporo Medical University School of Medicine, Sapporo, Japan
| | - Håkan Westerblad
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Daniel C Andersson
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden.,Heart, Vascular and Neurology Theme, Cardiology Unit, Karolinska University Hospital, Stockholm, Sweden
| | - Tatsuya Sato
- Department of Cellular Physiology and Signal Transduction, Sapporo Medical University School of Medicine, Sapporo, Japan.,Department of Cardiovascular, Renal and Metabolic Medicine, Sapporo Medical University School of Medicine, Sapporo, Japan
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7
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Maunder E, Bradley HE, Deane CS, Hodgson AB, Jones M, Joanisse S, Turner AM, Breen L, Philp A, Wallis GA. Effects of short-term graded dietary carbohydrate intake on intramuscular and whole body metabolism during moderate-intensity exercise. J Appl Physiol (1985) 2021; 131:376-387. [PMID: 34043470 DOI: 10.1152/japplphysiol.00811.2020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Altering dietary carbohydrate (CHO) intake modulates fuel utilization during exercise. However, there has been no systematic evaluation of metabolic responses to graded changes in short-term (< 1 wk) dietary CHO intake. Thirteen active men performed interval running exercise combined with isocaloric diets over 3 days before evaluation of metabolic responses to 60-min running at 65% V̇O2max on three occasions. Diets contained lower [LOW, 2.40 ± 0.66 g CHO·kg-1·day-1, 21.3 ± 0.5% of energy intake (EI)], moderate (MOD, 4.98 ± 1.31 g CHO·kg-1·day-1, 46.3 ± 0.7% EI), or higher (HIGH, 6.48 ± 1.56 g CHO·kg-1·day-1, 60.5 ± 1.6% EI) CHO. Preexercise muscle glycogen content was lower in LOW [54.3 ± 26.4 mmol·kg-1 wet weight (ww)] compared with MOD (82.6 ± 18.8 mmol·kg -1 ww) and HIGH (80.4 ± 26.0 mmol·kg-1 ww, P < 0.001; MOD vs. HIGH, P = 0.85). Whole body substrate oxidation, systemic responses, and muscle substrate utilization during exercise indicated increased fat and decreased CHO metabolism in LOW [respiratory exchange ratio (RER): 0.81 ± 0.01] compared with MOD (RER 0.86 ± 0.01, P = 0.0005) and HIGH (RER: 0.88 ± 0.01, P < 0.0001; MOD vs. HIGH, P = 0.14). Higher basal muscle expression of genes encoding proteins implicated in fat utilization was observed in LOW. In conclusion, muscle glycogen availability and subsequent metabolic responses to exercise were resistant to increases in dietary CHO intake from ∼5.0 to ∼6.5 g CHO·kg-1·day-1 (46% to 61% EI), while muscle glycogen, gene expression, and metabolic responses were sensitive to more marked reductions in CHO intake (∼2.4 g CHO·kg-1·day-1, ∼21% EI).NEW & NOTEWORTHY The data presented here suggest that metabolic responses to steady-state aerobic exercise are somewhat resistant to short-term changes in dietary carbohydrate (CHO) intake within the 5-6.5 g CHO·kg-1·day-1 [46-61% energy intake (EI)] range. In contrast, reduction in short-term dietary CHO intake to ∼2.4 g CHO·kg-1·day-1 (21% EI) evoked clear changes indicative of increased fat and decreased CHO metabolism during exercise.
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Affiliation(s)
- Ed Maunder
- Sports Performance Research Institute New Zealand, Auckland University of Technology, Auckland, New Zealand
| | - Helen E Bradley
- School of Sport, Exercise, and Rehabilitation Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Colleen S Deane
- Department of Sport and Health Sciences, College of Life and Environmental Sciences, University of Exeter, Exeter, United Kingdom.,Living Systems Institute, University of Exeter, Exeter, United Kingdom
| | | | - Michael Jones
- School of Sport, Exercise, and Rehabilitation Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Sophie Joanisse
- Department of Sport and Exercise Sciences, Manchester Metropolitan University, Manchester, United Kingdom
| | - Alice M Turner
- Institute for Applied Health Research, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom.,University Hospitals Birmingham National Health Services Foundation Trust, Heartlands Hospital, Birmingham, United Kingdom
| | - Leigh Breen
- School of Sport, Exercise, and Rehabilitation Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Andrew Philp
- Healthy Ageing Research Theme, Garvan Institute of Medical Research, Darlinghurst, New South Wales, Australia.,St. Vincent's Medical School, University of New South Wales Medicine, University of New South Wales Sydney, Sydney, New South Wales, Australia
| | - Gareth A Wallis
- School of Sport, Exercise, and Rehabilitation Sciences, University of Birmingham, Birmingham, United Kingdom
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McConell GK, Wadley GD, Le Plastrier K, Linden KC. Skeletal muscle AMPK is not activated during 2 h of moderate intensity exercise at ∼65% V ̇ O 2 peak in endurance trained men. J Physiol 2020; 598:3859-3870. [PMID: 32588910 PMCID: PMC7540472 DOI: 10.1113/jp277619] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2018] [Accepted: 06/17/2020] [Indexed: 12/22/2022] Open
Abstract
Key points AMP‐activated protein kinase (AMPK) is considered a major regulator of skeletal muscle metabolism during exercise. However, we previously showed that, although AMPK activity increases by 8–10‐fold during ∼120 min of exercise at ∼65% V˙O2peak in untrained individuals, there is no increase in these individuals after only 10 days of exercise training (longitudinal study). In a cross‐sectional study, we show that there is also a lack of activation of skeletal muscle AMPK during 120 min of cycling exercise at 65% V˙O2peak in endurance‐trained individuals. These findings indicate that AMPK is not an important regulator of exercise metabolism during 120 min of exercise at 65% V˙O2peak in endurance trained men. It is important that more energy is directed towards examining other potential regulators of exercise metabolism.
Abstract AMP‐activated protein kinase (AMPK) is considered a major regulator of skeletal muscle metabolism during exercise. Indeed, AMPK is activated during exercise and activation of AMPK by 5‐aminoimidazole‐4‐carboxyamide‐ribonucleoside (AICAR) increases skeletal muscle glucose uptake and fat oxidation. However, we have previously shown that, although AMPK activity increases by 8–10‐fold during ∼120 min of exercise at ∼65% V˙O2peak in untrained individuals, there is no increase in these individuals after only 10 days of exercise training (longitudinal study). In a cross‐sectional study, we examined whether there is also a lack of activation of skeletal muscle AMPK during 120 min of cycling exercise at 65% V˙O2peak in endurance‐trained individuals. Eleven untrained (UT; V˙O2peak = 37.9 ± 5.6 ml.kg−1 min−1) and seven endurance trained (ET; V˙O2peak = 61.8 ± 2.2 ml.kg−1 min−1) males completed 120 min of cycling exercise at 66 ± 4% V˙O2peak (UT: 100 ± 21 W; ET: 190 ± 15 W). Muscle biopsies were obtained at rest and following 30 and 120 min of exercise. Muscle glycogen was significantly (P < 0.05) higher before exercise in ET and decreased similarly during exercise in the ET and UT individuals. Exercise significantly increased calculated skeletal muscle free AMP content and more so in the UT individuals. Exercise significantly (P < 0.05) increased skeletal muscle AMPK α2 activity (4‐fold), AMPK αThr172 phosphorylation (2‐fold) and ACCβ Ser222 phosphorylation (2‐fold) in the UT individuals but not in the ET individuals. These findings indicate that AMPK is not an important regulator of exercise metabolism during 120 min of exercise at 65% V˙O2peak in endurance trained men. AMP‐activated protein kinase (AMPK) is considered a major regulator of skeletal muscle metabolism during exercise. However, we previously showed that, although AMPK activity increases by 8–10‐fold during ∼120 min of exercise at ∼65% V˙O2peak in untrained individuals, there is no increase in these individuals after only 10 days of exercise training (longitudinal study). In a cross‐sectional study, we show that there is also a lack of activation of skeletal muscle AMPK during 120 min of cycling exercise at 65% V˙O2peak in endurance‐trained individuals. These findings indicate that AMPK is not an important regulator of exercise metabolism during 120 min of exercise at 65% V˙O2peak in endurance trained men. It is important that more energy is directed towards examining other potential regulators of exercise metabolism.
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Affiliation(s)
- Glenn K McConell
- Institute for Health and Sport, Victoria University, Melbourne, VIC, Australia.,Department of Physiology, University of Melbourne, Melbourne, VIC, Australia
| | - Glenn D Wadley
- Department of Physiology, University of Melbourne, Melbourne, VIC, Australia.,Institute for Physical Activity and Nutrition, School of Exercise and Nutrition Sciences, Deakin University, Geelong, VIC, Australia
| | | | - Kelly C Linden
- Department of Physiology, University of Melbourne, Melbourne, VIC, Australia.,Faculty of Science, Charles Sturt University, Albury, NSW, Australia
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9
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Coccimiglio IF, Clarke DC. ADP is the dominant controller of AMP-activated protein kinase activity dynamics in skeletal muscle during exercise. PLoS Comput Biol 2020; 16:e1008079. [PMID: 32730244 PMCID: PMC7433884 DOI: 10.1371/journal.pcbi.1008079] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Revised: 08/18/2020] [Accepted: 06/19/2020] [Indexed: 01/14/2023] Open
Abstract
Exercise training elicits profound metabolic adaptations in skeletal muscle cells. A key molecule in coordinating these adaptations is AMP-activated protein kinase (AMPK), whose activity increases in response to cellular energy demand. AMPK activity dynamics are primarily controlled by the adenine nucleotides ADP and AMP, but how each contributes to its control in skeletal muscle during exercise is unclear. We developed and validated a mathematical model of AMPK signaling dynamics, and then applied global parameter sensitivity analyses with data-informed constraints to predict that AMPK activity dynamics are determined principally by ADP and not AMP. We then used the model to predict the effects of two additional direct-binding activators of AMPK, ZMP and Compound 991, further validating the model and demonstrating its applicability to understanding AMPK pharmacology. The relative effects of direct-binding activators can be understood in terms of four properties, namely their concentrations, binding affinities for AMPK, abilities to enhance AMPK phosphorylation, and the magnitudes of their allosteric activation of AMPK. Despite AMP's favorable values in three of these four properties, ADP is the dominant controller of AMPK activity dynamics in skeletal muscle during exercise by virtue of its higher concentration compared to that of AMP.
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Affiliation(s)
- Ian F. Coccimiglio
- Department of Biomedical Physiology and Kinesiology and Centre for Cell Biology, Development and Disease, Simon Fraser University, Burnaby, Canada
| | - David C. Clarke
- Department of Biomedical Physiology and Kinesiology and Centre for Cell Biology, Development and Disease, Simon Fraser University, Burnaby, Canada
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10
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Morissette MP, Susser SE, Stammers AN, Moffatt TL, Wigle JT, Wigle TJ, Netticadan T, Premecz S, Jassal DS, O’Hara KA, Duhamel TA. Exercise-induced increases in the expression and activity of cardiac sarcoplasmic reticulum calcium ATPase 2 is attenuated in AMPKα2kinase-dead mice. Can J Physiol Pharmacol 2019; 97:786-795. [DOI: 10.1139/cjpp-2018-0737] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Exercise enhances cardiac sarcoplasmic reticulum Ca2+-ATPase 2a (SERCA2a) function through unknown mechanisms. The present study tested the hypothesis that the positive effects of exercise on SERCA2a expression and function in the left ventricle is dependent on adenosine-monophosphate-activated protein kinase (AMPK) α2 function. AMPKα2kinase-dead (KD) transgenic mice, which overexpress inactivated AMPKα2subunit, and wild-type C57Bl/6 (WT) mice were randomized into sedentary groups or groups with access to running wheels. After 5 months, exercised KD mice exhibited shortened deceleration time compared with sedentary KD mice. In left ventricular tissue, the ratio of phosphorylated AMPKαThr172:total AMPKα was 65% lower (P < 0.05) in KD mice compared with WT mice. The left ventricle of KD mice had 37% lower levels of SERCA2a compared with WT mice. Although exercise increased SERCA2a protein levels in WT mice by 53%, this response of exercise was abolished in exercised KD mice. Exercise training reduced total phospholamban protein content by 23% in both the WT and KD mice but remained 20% higher overall in KD mice. Collectively, these data suggest that AMPKα influences SERCA2a and phospholamban protein content in the sedentary and exercised heart, and that exercise-induced changes in SERCA2a protein are dependent on AMPKα function.
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Affiliation(s)
- Marc P. Morissette
- Institute of Cardiovascular Sciences, St. Boniface Hospital Albrechtsen Research Centre, 351 Tache Avenue, Winnipeg, MB R2H 2A6, Canada
- Health, Leisure, and Human Performance Research Institute, Faculty of Kinesiology and Recreation Management, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
| | - Shanel E. Susser
- Institute of Cardiovascular Sciences, St. Boniface Hospital Albrechtsen Research Centre, 351 Tache Avenue, Winnipeg, MB R2H 2A6, Canada
- Health, Leisure, and Human Performance Research Institute, Faculty of Kinesiology and Recreation Management, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
- Department of Physiology and Pathophysiology, University of Manitoba, Winnipeg, MB R3E 0J9, Canada
| | - Andrew N. Stammers
- Institute of Cardiovascular Sciences, St. Boniface Hospital Albrechtsen Research Centre, 351 Tache Avenue, Winnipeg, MB R2H 2A6, Canada
- Health, Leisure, and Human Performance Research Institute, Faculty of Kinesiology and Recreation Management, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
| | - Teri L. Moffatt
- Institute of Cardiovascular Sciences, St. Boniface Hospital Albrechtsen Research Centre, 351 Tache Avenue, Winnipeg, MB R2H 2A6, Canada
- Health, Leisure, and Human Performance Research Institute, Faculty of Kinesiology and Recreation Management, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
| | - Jeffrey T. Wigle
- Institute of Cardiovascular Sciences, St. Boniface Hospital Albrechtsen Research Centre, 351 Tache Avenue, Winnipeg, MB R2H 2A6, Canada
- Department of Biochemistry and Medical Genetics, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB R2E 3N4, Canada
| | - Theodore J. Wigle
- Institute of Cardiovascular Sciences, St. Boniface Hospital Albrechtsen Research Centre, 351 Tache Avenue, Winnipeg, MB R2H 2A6, Canada
- Health, Leisure, and Human Performance Research Institute, Faculty of Kinesiology and Recreation Management, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
- Department of Physiology and Pathophysiology, University of Manitoba, Winnipeg, MB R3E 0J9, Canada
| | - Thomas Netticadan
- Department of Physiology and Pathophysiology, University of Manitoba, Winnipeg, MB R3E 0J9, Canada
- Canadian Centre for Agri-Food Research in Health and Medicine, St. Boniface Albrechtsen Research Centre, Winnipeg, MB R2H 2A6, Canada
- Agriculture and Agri-Food Canada, Winnipeg, MB R3C 3G7, Canada
| | - Sheena Premecz
- Institute of Cardiovascular Sciences, St. Boniface Hospital Albrechtsen Research Centre, 351 Tache Avenue, Winnipeg, MB R2H 2A6, Canada
| | - Davinder S. Jassal
- Institute of Cardiovascular Sciences, St. Boniface Hospital Albrechtsen Research Centre, 351 Tache Avenue, Winnipeg, MB R2H 2A6, Canada
- Canadian Centre for Agri-Food Research in Health and Medicine, St. Boniface Albrechtsen Research Centre, Winnipeg, MB R2H 2A6, Canada
- Section of Cardiology, Department of Internal Medicine, Max Rady College of Medicine, University of Manitoba, Winnipeg, MB R3A 1R9, Canada
| | - Kimberley A. O’Hara
- Institute of Cardiovascular Sciences, St. Boniface Hospital Albrechtsen Research Centre, 351 Tache Avenue, Winnipeg, MB R2H 2A6, Canada
- Health, Leisure, and Human Performance Research Institute, Faculty of Kinesiology and Recreation Management, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
| | - Todd A. Duhamel
- Institute of Cardiovascular Sciences, St. Boniface Hospital Albrechtsen Research Centre, 351 Tache Avenue, Winnipeg, MB R2H 2A6, Canada
- Health, Leisure, and Human Performance Research Institute, Faculty of Kinesiology and Recreation Management, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
- Department of Physiology and Pathophysiology, University of Manitoba, Winnipeg, MB R3E 0J9, Canada
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11
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Boufroura FZ, Le Bachelier C, Tomkiewicz-Raulet C, Schlemmer D, Benoist JF, Grondin P, Lamotte Y, Mirguet O, Mouillet-Richard S, Bastin J, Djouadi F. A new AMPK activator, GSK773, corrects fatty acid oxidation and differentiation defect in CPT2-deficient myotubes. Hum Mol Genet 2019; 27:3417-3433. [PMID: 30007356 DOI: 10.1093/hmg/ddy254] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Accepted: 07/04/2018] [Indexed: 02/07/2023] Open
Abstract
Carnitine palmitoyl transferase 2 (CPT2) deficiency is one of the most common inherited fatty acid oxidation (FAO) defects and represents a prototypical mitochondrial metabolic myopathy. Recent studies have suggested a pivotal role of adenosine monophosphate-activated protein kinase (AMPK) in skeletal muscle plasticity and mitochondrial homeostasis. Thus, we tested the potential of GSK773, a novel direct AMPK activator, to improve or correct FAO capacities in muscle cells from patients harboring various mutations. We used controls' and patients' myotubes and studied the parameters of FAO metabolism, of mitochondrial quantity and quality and of differentiation. We found that AMPK is constitutively activated in patients' myotubes, which exhibit both reduced FAO and impaired differentiation. GSK773 improves or corrects several metabolic hallmarks of CPT2 deficiency (deficient FAO flux and C16-acylcarnitine accumulation) by upregulating the expression of CPT2 protein. Beneficial effects of GSK773 are also likely due to stimulation of mitochondrial biogenesis and induction of mitochondrial fusion, by decreasing dynamin-related protein 1 and increasing mitofusin 2. GSK773 also induces a shift in myosin heavy chain isoforms toward the slow oxidative type and, therefore, fully corrects the differentiation process. We establish, through small interfering RNA knockdowns and pharmacological approaches, that these GSK773 effects are mediated through peroxisome proliferator-activated receptor gamma co-activator 1-alpha, reactive oxygen species and p38 mitogen-activated protein kinase, all key players of skeletal muscle plasticity. GSK773 recapitulates several important features of skeletal muscle adaptation to exercise. The results show that AMPK activation by GSK773 evokes the slow, oxidative myogenic program and triggers beneficial phenotypic adaptations in FAO-deficient myotubes. Thus, GSK773 might have therapeutic potential for correction of CPT2 deficiency.
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Affiliation(s)
- Fatima-Zohra Boufroura
- INSERM UMR-1124, Centre Universitaire des Saints-Pères, Université Paris Descartes, Paris, France
| | - Carole Le Bachelier
- INSERM UMR-1124, Centre Universitaire des Saints-Pères, Université Paris Descartes, Paris, France
| | - Céline Tomkiewicz-Raulet
- INSERM UMR-1124, Centre Universitaire des Saints-Pères, Université Paris Descartes, Paris, France
| | - Dimitri Schlemmer
- Service de Biochimie-Hormonologie, Centre de Référence des Maladies Héréditaires du Métabolisme, Hôpital Robert Debré, Paris, France
| | - Jean-François Benoist
- Service de Biochimie-Hormonologie, Centre de Référence des Maladies Héréditaires du Métabolisme, Hôpital Robert Debré, Paris, France
| | - Pascal Grondin
- Laboratoires Oncodesign, Centre de Recherches François Hyafil, 91140 Villebon-sur-Yvette, France
| | - Yann Lamotte
- Laboratoires Oncodesign, Centre de Recherches François Hyafil, 91140 Villebon-sur-Yvette, France
| | | | - Sophie Mouillet-Richard
- INSERM UMR-S1147 MEPPOT, Centre Universitaire des Saints-Pères, Université Sorbonne Paris Cité, Paris, France
| | - Jean Bastin
- INSERM UMR-1124, Centre Universitaire des Saints-Pères, Université Paris Descartes, Paris, France
| | - Fatima Djouadi
- INSERM UMR-1124, Centre Universitaire des Saints-Pères, Université Paris Descartes, Paris, France
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12
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Morgunova GV, Klebanov AA. Age-related AMP-activated protein kinase alterations: From cellular energetics to longevity. Cell Biochem Funct 2019; 37:169-176. [PMID: 30895648 DOI: 10.1002/cbf.3384] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Accepted: 02/05/2019] [Indexed: 12/18/2022]
Abstract
5' adenosine monophosphate-activated protein kinase (AMPK) is a key regulator of energy in the cell, which allows the cell/organism to survive with deficit of ATP. Since AMPK is involved in the adaptation to caloric restriction, the role of age-related changes in AMPK activity in both the aging organism and the aging cell is actively investigated in gerontology. Studies on yeast, worms, flies, rodents, and primates have demonstrated an important effect of this regulator on key signalling pathways involved in the aging process. In some cases, researchers conclude that AMPK promotes aging. However, in our opinion, in such cases, we observe a disturbance in the adaptive ability because of the prolonged cell/organism presence in stressful conditions because the functional capacity of any adaptation system is limited. Interestingly, AMPK can regulate metabolic processes in noncell-autonomous manner. The main effects of AMPK activation in the cell are realized in restriction of proliferation and launching autophagy. In tissues of an aging organism, the ability of AMPK to respond to energy deficit decreases; this fact is especially critical for organs that contain postmitotic cells. In this review, we have tried to consider the involvement of AMPK in age-related changes in the cell and in the organism.
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Affiliation(s)
- Galina V Morgunova
- Evolutionary Cytogerontology Sector, School of Biology, Lomonosov Moscow State University, Moscow, Russia
| | - Alexander A Klebanov
- Evolutionary Cytogerontology Sector, School of Biology, Lomonosov Moscow State University, Moscow, Russia
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13
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Montero D, Oberholzer L, Haider T, Breenfeldt-Andersen A, Dandanell S, Meinild-Lundby AK, Maconochie H, Lundby C. Increased capillary density in skeletal muscle is not associated with impaired insulin sensitivity induced by bed rest in healthy young men. Appl Physiol Nutr Metab 2018; 43:1334-1340. [DOI: 10.1139/apnm-2018-0195] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Physical inactivity alters glucose homeostasis in skeletal muscle, potentially developing into overt metabolic disease. The present study sought to investigate the role of skeletal muscle capillarization in glucose tolerance and insulin sensitivity (IS) using a classic human model of physical inactivity. Thirteen healthy males (age = 23 ± 2 years) underwent 4 days of full-time supervised and diet-controlled bed rest. Oral glucose tolerance test, indices of IS (quantitative insulin sensitivity check index (QUICKI), Matsuda index), as well as skeletal muscle biopsies with measurement of fiber type distribution, fiber cross-sectional area (FCSA), capillary-to-fiber ratio (C/F ratio), and capillary density (CD) were assessed prior to and after bed rest. Body weight and composition were unaltered by bed rest. Fasting glucose/insulin ratio (G0/I0 ratio) (−25%, P = 0.016), QUICKI (−7%, P = 0.023), and Matsuda index (−24%, P = 0.003) diminished with bed rest. Skeletal muscle FCSA decreased (−737.4 ± 763.2 μm−2 (−12%), P = 0.005) while C/F ratio was preserved, resulting in augmented CD (+93.9 ± 91.5 capillaries·mm−2 (+37%), P = 0.003) with bed rest. No association was detected between changes in skeletal muscle variables and metabolic outcomes. Independently of bed rest-induced effects, a positive linear relationship was detected between C/F ratio and G0/I0 ratio (β = 17.09, P = 0.021). In conclusion, impaired glucose homeostasis with bed rest is not prevented nor associated with enhanced skeletal muscle capillarization in healthy individuals.
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Affiliation(s)
- David Montero
- Department of Cardiology, University Hospital of Zurich, Switzerland
| | - Laura Oberholzer
- Center for Physical Activity Research, University Hospital of Copenhagen, Denmark
| | - Thomas Haider
- Zurich Center for Integrative Human Physiology, Institute of Physiology, University of Zurich, Switzerland
| | | | - Sune Dandanell
- Zurich Center for Integrative Human Physiology, Institute of Physiology, University of Zurich, Switzerland
| | | | - Hannah Maconochie
- Center for Physical Activity Research, University Hospital of Copenhagen, Denmark
| | - Carsten Lundby
- Center for Physical Activity Research, University Hospital of Copenhagen, Denmark
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14
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Steenberg DE, Jørgensen NB, Birk JB, Sjøberg KA, Kiens B, Richter EA, Wojtaszewski JFP. Exercise training reduces the insulin-sensitizing effect of a single bout of exercise in human skeletal muscle. J Physiol 2018; 597:89-103. [PMID: 30325018 DOI: 10.1113/jp276735] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Accepted: 10/11/2018] [Indexed: 12/26/2022] Open
Abstract
KEY POINTS A single bout of exercise is capable of increasing insulin sensitivity in human skeletal muscle. Whether this ability is affected by training status is not clear. Studies in mice suggest that the AMPK-TBC1D4 signalling axis is important for the increased insulin-stimulated glucose uptake after a single bout of exercise. The present study is the first longitudinal intervention study to show that, although exercise training increases insulin-stimulated glucose uptake in skeletal muscle at rest, it diminishes the ability of a single bout of exercise to enhance muscle insulin-stimulated glucose uptake. The present study provides novel data indicating that AMPK in human skeletal muscle is important for the insulin-sensitizing effect of a single bout of exercise. ABSTRACT Not only chronic exercise training, but also a single bout of exercise, increases insulin-stimulated glucose uptake in skeletal muscle. However, it is not well described how adaptations to exercise training affect the ability of a single bout of exercise to increase insulin sensitivity. Rodent studies suggest that the insulin-sensitizing effect of a single bout of exercise is AMPK-dependent (presumably via the α2 β2 γ3 AMPK complex). Whether this is also the case in humans is unknown. Previous studies have shown that exercise training decreases the expression of the α2 β2 γ3 AMPK complex and diminishes the activation of this complex during exercise. Thus, we hypothesized that exercise training diminishes the ability of a single bout of exercise to enhance muscle insulin sensitivity. We investigated nine healthy male subjects who performed one-legged knee-extensor exercise at the same relative intensity before and after 12 weeks of exercise training. Training increased V ̇ O 2 peak and expression of mitochondrial proteins in muscle, whereas the expression of AMPKγ3 was decreased. Training also increased whole body and muscle insulin sensitivity. Interestingly, insulin-stimulated glucose uptake in the acutely exercised leg was not enhanced further by training. Thus, the increase in insulin-stimulated glucose uptake following a single bout of one-legged exercise was lower in the trained vs. untrained state. This was associated with reduced signalling via confirmed α2 β2 γ3 AMPK downstream targets (ACC and TBC1D4). These results suggest that the insulin-sensitizing effect of a single bout of exercise is also AMPK-dependent in human skeletal muscle.
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Affiliation(s)
- Dorte E Steenberg
- Department of Nutrition, Exercise and Sports, Section of Molecular Physiology, University of Copenhagen, Copenhagen, Denmark
| | - Nichlas B Jørgensen
- Department of Nutrition, Exercise and Sports, Section of Molecular Physiology, University of Copenhagen, Copenhagen, Denmark
| | - Jesper B Birk
- Department of Nutrition, Exercise and Sports, Section of Molecular Physiology, University of Copenhagen, Copenhagen, Denmark
| | - Kim A Sjøberg
- Department of Nutrition, Exercise and Sports, Section of Molecular Physiology, University of Copenhagen, Copenhagen, Denmark
| | - Bente Kiens
- Department of Nutrition, Exercise and Sports, Section of Molecular Physiology, University of Copenhagen, Copenhagen, Denmark
| | - Erik A Richter
- Department of Nutrition, Exercise and Sports, Section of Molecular Physiology, University of Copenhagen, Copenhagen, Denmark
| | - Jørgen F P Wojtaszewski
- Department of Nutrition, Exercise and Sports, Section of Molecular Physiology, University of Copenhagen, Copenhagen, Denmark
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15
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The Role of AMPK in the Regulation of Skeletal Muscle Size, Hypertrophy, and Regeneration. Int J Mol Sci 2018; 19:ijms19103125. [PMID: 30314396 PMCID: PMC6212977 DOI: 10.3390/ijms19103125] [Citation(s) in RCA: 127] [Impact Index Per Article: 21.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Revised: 10/08/2018] [Accepted: 10/09/2018] [Indexed: 12/22/2022] Open
Abstract
AMPK (5’-adenosine monophosphate-activated protein kinase) is heavily involved in skeletal muscle metabolic control through its regulation of many downstream targets. Because of their effects on anabolic and catabolic cellular processes, AMPK plays an important role in the control of skeletal muscle development and growth. In this review, the effects of AMPK signaling, and those of its upstream activator, liver kinase B1 (LKB1), on skeletal muscle growth and atrophy are reviewed. The effect of AMPK activity on satellite cell-mediated muscle growth and regeneration after injury is also reviewed. Together, the current data indicate that AMPK does play an important role in regulating muscle mass and regeneration, with AMPKα1 playing a prominent role in stimulating anabolism and in regulating satellite cell dynamics during regeneration, and AMPKα2 playing a potentially more important role in regulating muscle degradation during atrophy.
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16
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Isoform-specific AMPK association with TBC1D1 is reduced by a mutation associated with severe obesity. Biochem J 2018; 475:2969-2983. [PMID: 30135087 PMCID: PMC6156765 DOI: 10.1042/bcj20180475] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2018] [Revised: 08/10/2018] [Accepted: 08/22/2018] [Indexed: 01/08/2023]
Abstract
AMP-activated protein kinase (AMPK) is a key regulator of cellular and systemic energy homeostasis which achieves this through the phosphorylation of a myriad of downstream targets. One target is TBC1D1 a Rab-GTPase-activating protein that regulates glucose uptake in muscle cells by integrating insulin signalling with that promoted by muscle contraction. Ser237 in TBC1D1 is a target for phosphorylation by AMPK, an event which may be important in regulating glucose uptake. Here, we show AMPK heterotrimers containing the α1, but not the α2, isoform of the catalytic subunit form an unusual and stable association with TBC1D1, but not its paralogue AS160. The interaction between the two proteins is direct, involves a dual interaction mechanism employing both phosphotyrosine-binding (PTB) domains of TBC1D1 and is increased by two different pharmacological activators of AMPK (AICAR and A769962). The interaction enhances the efficiency by which AMPK phosphorylates TBC1D1 on its key regulatory site, Ser237. Furthermore, the interaction is reduced by a naturally occurring R125W mutation in the PTB1 domain of TBC1D1, previously found to be associated with severe familial obesity in females, with a concomitant reduction in Ser237 phosphorylation. Our observations provide evidence for a functional difference between AMPK α-subunits and extend the repertoire of protein kinases that interact with substrates via stabilisation mechanisms that modify the efficacy of substrate phosphorylation.
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17
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Popov DV, Lysenko EA, Bokov RO, Volodina MA, Kurochkina NS, Makhnovskii PA, Vyssokikh MY, Vinogradova OL. Effect of aerobic training on baseline expression of signaling and respiratory proteins in human skeletal muscle. Physiol Rep 2018; 6:e13868. [PMID: 30198217 PMCID: PMC6129775 DOI: 10.14814/phy2.13868] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Accepted: 08/24/2018] [Indexed: 12/30/2022] Open
Abstract
Most studies examining the molecular mechanisms underlying adaptation of human skeletal muscles to aerobic exercise focused on the response to acute exercise. Here, we examined the effect of a 2-month aerobic training program on baseline parameters in human muscle. Ten untrained males performed a one-legged knee extension exercise for 1 h with the same relative intensity before and after a 2-month aerobic training program. Biopsy samples were taken from vastus lateralis muscle at rest before and after the 2 month training program (baseline samples). Additionally, biopsy samples were taken from the exercised leg 1 and 4 h after the one-legged continuous knee extension exercise. Aerobic training decreases baseline phosphorylation of FOXO1Ser256 , increases that of CaMKIIThr286 , CREB1Ser133 , increases baseline expression of mitochondrial proteins in respiratory complexes I-V, and some regulators of mitochondrial biogenesis (TFAM, NR4A3, and CRTC2). An increase in the baseline content of these proteins was not associated with a change in baseline expression of their genes. The increase in the baseline content of regulators of mitochondrial biogenesis (TFAM and NR4A3) was associated with a transient increase in transcription after acute exercise. Contrariwise, the increase in the baseline content of respiratory proteins does not seem to be regulated at the transcriptional level; rather, it is associated with other mechanisms. Adaptation of human skeletal muscle to regular aerobic exercise is associated not only with transient molecular responses to exercise, but also with changes in baseline phosphorylation and expression of regulatory proteins.
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Affiliation(s)
- Daniil V. Popov
- Laboratory of Exercise PhysiologyInstitute of Biomedical Problems of the Russian Academy of SciencesMoscowRussia
- Faculty of Fundamental MedicineM.V. Lomonosov Moscow State UniversityMoscowRussia
| | - Evgeny A. Lysenko
- Laboratory of Exercise PhysiologyInstitute of Biomedical Problems of the Russian Academy of SciencesMoscowRussia
- Faculty of Fundamental MedicineM.V. Lomonosov Moscow State UniversityMoscowRussia
| | - Roman O. Bokov
- Laboratory of Exercise PhysiologyInstitute of Biomedical Problems of the Russian Academy of SciencesMoscowRussia
| | - Maria A. Volodina
- Laboratory of Mitochondrial MedicineResearch Center for ObstetricsGynecology and PerinatologyMinistry of Healthcare of the Russian FederationMoscowRussia
| | - Nadia S. Kurochkina
- Laboratory of Exercise PhysiologyInstitute of Biomedical Problems of the Russian Academy of SciencesMoscowRussia
| | - Pavel A. Makhnovskii
- Laboratory of Exercise PhysiologyInstitute of Biomedical Problems of the Russian Academy of SciencesMoscowRussia
| | - Mikhail Y. Vyssokikh
- Laboratory of Mitochondrial MedicineResearch Center for ObstetricsGynecology and PerinatologyMinistry of Healthcare of the Russian FederationMoscowRussia
| | - Olga L. Vinogradova
- Laboratory of Exercise PhysiologyInstitute of Biomedical Problems of the Russian Academy of SciencesMoscowRussia
- Faculty of Fundamental MedicineM.V. Lomonosov Moscow State UniversityMoscowRussia
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18
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Intensity-dependent gene expression after aerobic exercise in endurance-trained skeletal muscle. Biol Sport 2018; 35:277-289. [PMID: 30449946 PMCID: PMC6224845 DOI: 10.5114/biolsport.2018.77828] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Revised: 09/14/2017] [Accepted: 03/16/2018] [Indexed: 01/06/2023] Open
Abstract
We investigated acute exercise-induced gene expression in skeletal muscle adapted to aerobic training. Vastus lateralis muscle samples were taken in ten endurance-trained males prior to, and just after, 4 h, and 8 h after acute cycling sessions with different intensities, 70% and 50% V˙O2max. High-throughput RNA sequencing was applied in samples from two subjects to evaluate differentially expressed genes after intensive exercise (70% V˙O2max), and then the changes in expression for selected genes were validated by quantitative PCR (qPCR). To define exercise-induced genes, we compared gene expression after acute exercise with different intensities, 70% and 50% V˙O2max, by qPCR. The transcriptome is dynamically changed during the first hours of recovery after intensive exercise (70% V˙O2max). A computational approach revealed that the changes might be related to up- and down-regulation of the activity of transcription activators and repressors, respectively. The exercise increased expression of many genes encoding protein kinases, while genes encoding transcriptional regulators were both up- and down-regulated. Evaluation of the gene expression after exercise with different intensities revealed that some genes changed expression in an intensity-dependent manner, but others did not: the majority of genes encoding protein kinases, oxidative phosphorylation and activator protein (AP)-1-related genes significantly correlated with markers of exercise stress (power, blood lactate during exercise and post-exercise blood cortisol), while transcriptional repressors and circadian-related genes did not. Some of the changes in gene expression after exercise seemingly may be modulated by circadian rhythm.
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19
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Stefani L, Sofi F, Magro S, Mascherini G, Petri C, Galanti G. Exercise and Cancer Survivors: Lessons Learned from a Multi-Faceted Model for Exercise Prescription. J Funct Morphol Kinesiol 2018; 3:jfmk3030038. [PMID: 33466967 PMCID: PMC7739294 DOI: 10.3390/jfmk3030038] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/15/2018] [Revised: 06/01/2018] [Accepted: 06/22/2018] [Indexed: 01/20/2023] Open
Abstract
Cancer is the second leading cause of death, and the most common diagnosis among the general population is breast and colon cancer. Recently, an increasing number of new cases of invasive breast and colon cancer have been estimated, and more people die from these diseases. In addition to the genetic pattern, diet and lifestyle including smoking, alcohol consumption, and sedentary behaviour have also been identified as potential risks factors. Recent studies of cancer survivors have shown the beneficial effects of regular physical activity to reduce the prevalence of comorbidity, muscle atrophy, weight changes, reduced aerobic capacity, fatigue, depression, and reduced quality of life. Dedicated and individual programs are crucial for achieving the goals of improving quality of life and reducing comorbidities. A multidisciplinary approach is fundamental: lifestyle assessment, including estimating the level of physical activity, as well as nutritional habits, may be the first step. A periodic cardiovascular examination is crucial for detecting asymptomatic early myocardial failure. According to current ACSM guidelines, different levels of exercise (low-moderate 40% and moderate up to 60% of the maximal HR) may be prescribed, and patients enrolled may follow the exercise program if in the absence of contraindications. The current paper reports observations from our clinical practice and provides practical strategies that bridge contemporary, published guidelines into practice within a multi-disciplinary team working with cancer survivors in Italy.
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Affiliation(s)
- Laura Stefani
- Unit of Sports Medicine, Department of Experimental and Clinical Medicine, University of Florence, 50141 Florence, Italy
- Correspondence: ; Tel.: +39-3477689030
| | - Francesco Sofi
- Unit of Clinical Nutrition, Department of Experimental and Clinical Medicine, University of Florence, 50134 Florence, Italy
| | - Simone Magro
- Unit of Sports Medicine, Department of Experimental and Clinical Medicine, University of Florence, 50141 Florence, Italy
| | - Gabriele Mascherini
- Unit of Sports Medicine, Department of Experimental and Clinical Medicine, University of Florence, 50141 Florence, Italy
| | - Cristian Petri
- Unit of Sports Medicine, Department of Experimental and Clinical Medicine, University of Florence, 50141 Florence, Italy
| | - Giorgio Galanti
- Unit of Sports Medicine, Department of Experimental and Clinical Medicine, University of Florence, 50141 Florence, Italy
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20
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de Lima EA, de Sousa LGO, de S Teixeira AA, Marshall AG, Zanchi NE, Neto JCR. Aerobic exercise, but not metformin, prevents reduction of muscular performance by AMPk activation in mice on doxorubicin chemotherapy. J Cell Physiol 2018; 233:9652-9662. [PMID: 29953589 DOI: 10.1002/jcp.26880] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Accepted: 05/23/2018] [Indexed: 01/20/2023]
Abstract
Doxorubicin (DOX) is a chemotherapy agent widely used in clinical practice, and it is very efficient in tumor suppression, but the use of DOX is limited by a strong association with the development of severe muscle atrophy and cardiotoxicity effects. Reversion or neutralization of the muscular atrophy can lead to a better prognosis. Recent studies have proposed that the negative effect of DOX on skeletal muscle is linked to its inhibition of AMP-activated protein kinase (AMPk), a key mediator of cellular metabolism. On the basis of this, our goal was to evaluate if aerobic exercise or metformin treatment, activators of AMPk, would be able to attenuate the deleterious effects on skeletal muscle induced by the DOX treatment. C57BL6 mice received either saline (control) or DOX (2.5 mg/kg body weight) intraperitoneally, twice a week. The animals on DOX were further divided into groups that received adjuvant treatment in the form of moderate aerobic physical exercise (DOX+T) or metformin gavage (300 mg/body weight/day). Body weight, metabolism, distance run, muscle fiber cross-sectional area (CSA), and protein synthesis and degradation were assessed. We demonstrated that aerobic training, but not metformin, associated with DOX increased the maximal aerobic capacity without changing muscle mass or fiber CSA, rescuing the muscle fatigue observed with DOX treatment alone. This improvement was associated with AMPk activation, thus surpassing the negative effects of DOX on muscle performance and bioenergetics. In conclusion, aerobic exercise increases AMPk activation and improved the skeletal muscle function, reducing the side effects of DOX.
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Affiliation(s)
- Edson A de Lima
- Immunometabolism Research Group, Department of Cell and Developmental Biology, University of São Paulo, Butantã, São Paulo, Brazil
| | - Luís G O de Sousa
- Department of Internal Medicine, Division of Endocrinology and Metabolism, University of Iowa, Iowa City, IA
| | - Alexandre Abilio de S Teixeira
- Immunometabolism Research Group, Department of Cell and Developmental Biology, University of São Paulo, Butantã, São Paulo, Brazil
| | - Andrea G Marshall
- Department of Internal Medicine, Division of Endocrinology and Metabolism, University of Iowa, Iowa City, IA
| | - Nelo E Zanchi
- Laboratory of Cellular and Molecular Biology of Skeletal Muscle (LABCEMME), Department of Physical Education, Federal University of Maranhão (UFMA), São Luís, Maranhão, Brazil
| | - José C Rosa Neto
- Immunometabolism Research Group, Department of Cell and Developmental Biology, University of São Paulo, Butantã, São Paulo, Brazil
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21
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Popov DV. Adaptation of Skeletal Muscles to Contractile Activity of Varying Duration and Intensity: The Role of PGC-1α. BIOCHEMISTRY (MOSCOW) 2018; 83:613-628. [DOI: 10.1134/s0006297918060019] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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22
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Tobias IS, Lazauskas KK, Arevalo JA, Bagley JR, Brown LE, Galpin AJ. Fiber type-specific analysis of AMPK isoforms in human skeletal muscle: advancement in methods via capillary nanoimmunoassay. J Appl Physiol (1985) 2018; 124:840-849. [DOI: 10.1152/japplphysiol.00894.2017] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Human skeletal muscle is a heterogeneous mixture of multiple fiber types (FT). Unfortunately, present methods for FT-specific study are constrained by limits of protein detection in single-fiber samples. These limitations beget compensatory resource-intensive procedures, ultimately dissuading investigators from pursuing FT-specific research. Additionally, previous studies neglected hybrid FT, confining their analyses to only pure FT. Here we present novel methods of protein detection across a wider spectrum of human skeletal muscle FT using fully automated capillary nanoimmunoassay (CNIA) technology. CNIA allowed a ~20-fold-lower limit of 5′-AMP-activated protein kinase (AMPK) detection compared with Western blotting. We then performed FT-specific assessment of AMPK expression as a proof of concept. Individual human muscle fibers were mechanically isolated, dissolved, and myosin heavy chain (MHC) fiber typed via SDS-PAGE. Single-fiber samples were combined in pairs and grouped into MHC I, MHC I/IIa, MHC IIa, and MHC IIa/IIx for expression analysis of AMPK isoforms α1, α2, β1, β2, γ2, and γ3 with a tubulin loading control. Significant FT-specific differences were found for α2 (1.7-fold higher in MHC IIa and MHC IIa/IIx vs. others), γ2 (2.5-fold higher in MHC IIa vs. others), and γ3 (2-fold higher in MHC IIa and 4-fold higher in MHC IIa/IIx vs. others). Development of a protocol that combines the efficient and sensitive CNIA technology with comprehensive SDS-PAGE fiber typing marks an important advancement in FT-specific research because it allows more precise study of the molecular mechanisms governing metabolism, adaptation, and regulation in human muscle. NEW & NOTEWORTHY We demonstrate the viability of applying capillary nanoimmunoassay technology to the study of fiber type-specific protein analysis in human muscle fibers. This novel technique enables a ~20-fold-lower limit of protein detection compared with traditional Western blotting methods. Combined with SDS-PAGE methods of fiber typing, we apply this technique to compare 5′-AMP-activated protein kinase isoform expression in myosin heavy chain (MHC) I, MHC I/IIa, MHC IIa, and MHC IIa/IIx fiber types.
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Affiliation(s)
- Irene S. Tobias
- Biochemistry and Molecular Exercise Physiology Laboratory, Center for Sport Performance, California State University, Fullerton, California
| | - Kara K. Lazauskas
- Biochemistry and Molecular Exercise Physiology Laboratory, Center for Sport Performance, California State University, Fullerton, California
| | - Jose A. Arevalo
- Biochemistry and Molecular Exercise Physiology Laboratory, Center for Sport Performance, California State University, Fullerton, California
| | - James R. Bagley
- Muscle Physiology Laboratory, Department of Kinesiology, San Francisco State University, San Francisco, California
| | - Lee E. Brown
- Biochemistry and Molecular Exercise Physiology Laboratory, Center for Sport Performance, California State University, Fullerton, California
| | - Andrew J. Galpin
- Biochemistry and Molecular Exercise Physiology Laboratory, Center for Sport Performance, California State University, Fullerton, California
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23
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Kjøbsted R, Hingst JR, Fentz J, Foretz M, Sanz MN, Pehmøller C, Shum M, Marette A, Mounier R, Treebak JT, Wojtaszewski JFP, Viollet B, Lantier L. AMPK in skeletal muscle function and metabolism. FASEB J 2018; 32:1741-1777. [PMID: 29242278 PMCID: PMC5945561 DOI: 10.1096/fj.201700442r] [Citation(s) in RCA: 275] [Impact Index Per Article: 45.8] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Skeletal muscle possesses a remarkable ability to adapt to various physiologic conditions. AMPK is a sensor of intracellular energy status that maintains energy stores by fine-tuning anabolic and catabolic pathways. AMPK’s role as an energy sensor is particularly critical in tissues displaying highly changeable energy turnover. Due to the drastic changes in energy demand that occur between the resting and exercising state, skeletal muscle is one such tissue. Here, we review the complex regulation of AMPK in skeletal muscle and its consequences on metabolism (e.g., substrate uptake, oxidation, and storage as well as mitochondrial function of skeletal muscle fibers). We focus on the role of AMPK in skeletal muscle during exercise and in exercise recovery. We also address adaptations to exercise training, including skeletal muscle plasticity, highlighting novel concepts and future perspectives that need to be investigated. Furthermore, we discuss the possible role of AMPK as a therapeutic target as well as different AMPK activators and their potential for future drug development.—Kjøbsted, R., Hingst, J. R., Fentz, J., Foretz, M., Sanz, M.-N., Pehmøller, C., Shum, M., Marette, A., Mounier, R., Treebak, J. T., Wojtaszewski, J. F. P., Viollet, B., Lantier, L. AMPK in skeletal muscle function and metabolism.
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Affiliation(s)
- Rasmus Kjøbsted
- Section of Molecular Physiology, Department of Nutrition, Exercise, and Sports, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
| | - Janne R Hingst
- Section of Molecular Physiology, Department of Nutrition, Exercise, and Sports, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
| | - Joachim Fentz
- Section of Molecular Physiology, Department of Nutrition, Exercise, and Sports, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
| | - Marc Foretz
- INSERM, Unité 1016, Institut Cochin, Paris, France.,Centre National de la Recherche Scientifique (CNRS), Unité Mixte de Recherche (UMR) 8104, Paris, France.,Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Maria-Nieves Sanz
- Department of Cardiovascular Surgery, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland, and.,Department of Biomedical Research, University of Bern, Bern, Switzerland
| | - Christian Pehmøller
- Internal Medicine Research Unit, Pfizer Global Research and Development, Cambridge, Massachusetts, USA
| | - Michael Shum
- Axe Cardiologie, Quebec Heart and Lung Research Institute, Laval University, Québec, Canada.,Institute for Nutrition and Functional Foods, Laval University, Québec, Canada
| | - André Marette
- Axe Cardiologie, Quebec Heart and Lung Research Institute, Laval University, Québec, Canada.,Institute for Nutrition and Functional Foods, Laval University, Québec, Canada
| | - Remi Mounier
- Institute NeuroMyoGène, Université Claude Bernard Lyon 1, INSERM Unité 1217, CNRS UMR, Villeurbanne, France
| | - Jonas T Treebak
- Section of Integrative Physiology, Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Jørgen F P Wojtaszewski
- Section of Molecular Physiology, Department of Nutrition, Exercise, and Sports, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
| | - Benoit Viollet
- INSERM, Unité 1016, Institut Cochin, Paris, France.,Centre National de la Recherche Scientifique (CNRS), Unité Mixte de Recherche (UMR) 8104, Paris, France.,Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Louise Lantier
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee, USA.,Mouse Metabolic Phenotyping Center, Vanderbilt University, Nashville, Tennessee, USA
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24
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Lysenko EA, Vepkhvadze TF, Lednev EM, Vinogradova OL, Popov DV. Branched-chain amino acids administration suppresses endurance exercise-related activation of ubiquitin proteasome signaling in trained human skeletal muscle. J Physiol Sci 2018; 68:43-53. [PMID: 27913948 PMCID: PMC10717082 DOI: 10.1007/s12576-016-0506-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2016] [Accepted: 11/15/2016] [Indexed: 12/31/2022]
Abstract
We tested whether post exercise ingestion of branched-chain amino acids (BCAA < 10 g) is sufficient to activate signaling associated with muscle protein synthesis and suppress exercise-induced activation of mechanisms associated with proteolysis in endurance-trained human skeletal muscle. Nine endurance-trained athletes performed a cycling bout with and without BCAA ingestion (0.1 g/kg). Post exercise ACCSer79/222 phosphorylation (endogenous marker of AMPK activity) was increased (~3-fold, P < 0.05) in both sessions. No changes were observed in IGF1 mRNA isoform expression or phosphorylation of the key anabolic markers - p70S6K1Thr389 and eEF2Thr56 - between the sessions. BCAA administration suppressed exercise-induced expression of mTORC1 inhibitor DDIT4 mRNA, eliminated activation of the ubiquitin proteasome system, detected in the control session as decreased FOXO1Ser256 phosphorylation (0.83-fold change, P < 0.05) and increased TRIM63 (MURF1) expression (2.4-fold, P < 0.05). Therefore, in endurance-trained human skeletal muscle, post exercise BCAA ingestion partially suppresses exercise-induced expression of PGC-1a mRNA, activation of ubiquitin proteasome signaling, and suppresses DDIT4 mRNA expression.
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Affiliation(s)
- Evgeny A Lysenko
- Laboratory of Exercise Physiology, Institute of Biomedical Problems, Russian Academy of Sciences, Khoroshevskoye shosse, 76A, Moscow, 123007, Russia.
- Faculty of Fundamental Medicine, M.V. Lomonosov Moscow State University, Lomonosovsky Prospect, 27-1, Moscow, 119192, Russia.
| | - Tatiana F Vepkhvadze
- Laboratory of Exercise Physiology, Institute of Biomedical Problems, Russian Academy of Sciences, Khoroshevskoye shosse, 76A, Moscow, 123007, Russia
| | - Egor M Lednev
- Faculty of Fundamental Medicine, M.V. Lomonosov Moscow State University, Lomonosovsky Prospect, 27-1, Moscow, 119192, Russia
| | - Olga L Vinogradova
- Laboratory of Exercise Physiology, Institute of Biomedical Problems, Russian Academy of Sciences, Khoroshevskoye shosse, 76A, Moscow, 123007, Russia
- Faculty of Fundamental Medicine, M.V. Lomonosov Moscow State University, Lomonosovsky Prospect, 27-1, Moscow, 119192, Russia
| | - Daniil V Popov
- Laboratory of Exercise Physiology, Institute of Biomedical Problems, Russian Academy of Sciences, Khoroshevskoye shosse, 76A, Moscow, 123007, Russia
- Faculty of Fundamental Medicine, M.V. Lomonosov Moscow State University, Lomonosovsky Prospect, 27-1, Moscow, 119192, Russia
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25
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Kjøbsted R, Wojtaszewski JFP, Treebak JT. Role of AMP-Activated Protein Kinase for Regulating Post-exercise Insulin Sensitivity. ACTA ACUST UNITED AC 2017; 107:81-126. [PMID: 27812978 DOI: 10.1007/978-3-319-43589-3_5] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Skeletal muscle insulin resistance precedes development of type 2 diabetes (T2D). As skeletal muscle is a major sink for glucose disposal, understanding the molecular mechanisms involved in maintaining insulin sensitivity of this tissue could potentially benefit millions of people that are diagnosed with insulin resistance. Regular physical activity in both healthy and insulin-resistant individuals is recognized as the single most effective intervention to increase whole-body insulin sensitivity and thereby positively affect glucose homeostasis. A single bout of exercise has long been known to increase glucose disposal in skeletal muscle in response to physiological insulin concentrations. While this effect is identified to be restricted to the previously exercised muscle, the molecular basis for an apparent convergence between exercise- and insulin-induced signaling pathways is incompletely known. In recent years, we and others have identified the Rab GTPase-activating protein, TBC1 domain family member 4 (TBC1D4) as a target of key protein kinases in the insulin- and exercise-activated signaling pathways. Our working hypothesis is that the AMP-activated protein kinase (AMPK) is important for the ability of exercise to insulin sensitize skeletal muscle through TBC1D4. Here, we aim to provide an overview of the current available evidence linking AMPK to post-exercise insulin sensitivity.
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Affiliation(s)
- Rasmus Kjøbsted
- Novo Nordisk Foundation Center for Basic Metabolic Research, Section of Integrative Physiology, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3b, 2200, Copenhagen, Denmark
- Section of Molecular Physiology, Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, 2100, Copenhagen, Denmark
| | - Jørgen F P Wojtaszewski
- Section of Molecular Physiology, Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, 2100, Copenhagen, Denmark
| | - Jonas T Treebak
- Novo Nordisk Foundation Center for Basic Metabolic Research, Section of Integrative Physiology, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3b, 2200, Copenhagen, Denmark.
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26
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Guadalupe-Grau A, Fernández-Elías VE, Ortega JF, Dela F, Helge JW, Mora-Rodriguez R. Effects of 6-month aerobic interval training on skeletal muscle metabolism in middle-aged metabolic syndrome patients. Scand J Med Sci Sports 2017; 28:585-595. [DOI: 10.1111/sms.12881] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/06/2017] [Indexed: 12/20/2022]
Affiliation(s)
- A. Guadalupe-Grau
- Xlab; Department of Biomedical Sciences; Faculty of Health Sciences; Center for Healthy Aging; University of Copenhagen; Copenhagen Denmark
- ImFINE Research Group; Department of Health and Human Performance; Technical University of Madrid; Madrid Spain
| | - V. E. Fernández-Elías
- Exercise Physiology Laboratory at Toledo; University of Castilla-La Mancha; Toledo Spain
- Department of Sport Science; European University of Madrid; Madrid Spain
| | - J. F. Ortega
- Exercise Physiology Laboratory at Toledo; University of Castilla-La Mancha; Toledo Spain
| | - F. Dela
- Xlab; Department of Biomedical Sciences; Faculty of Health Sciences; Center for Healthy Aging; University of Copenhagen; Copenhagen Denmark
| | - J. W. Helge
- Xlab; Department of Biomedical Sciences; Faculty of Health Sciences; Center for Healthy Aging; University of Copenhagen; Copenhagen Denmark
| | - R. Mora-Rodriguez
- Exercise Physiology Laboratory at Toledo; University of Castilla-La Mancha; Toledo Spain
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27
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Visceral fat area is a strong predictor of leukocyte cell-derived chemotaxin 2, a potential biomarker of dyslipidemia. PLoS One 2017; 12:e0173310. [PMID: 28278265 PMCID: PMC5344404 DOI: 10.1371/journal.pone.0173310] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Accepted: 02/17/2017] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND Leukocyte cell-derived chemotaxin 2 (LECT2) is a hepatokine linking obesity to skeletal muscle insulin resistance. Although previous studies reported that obesity was associated with high levels of circulating LECT2 in human, the associations of detailed body fat distribution with LECT2 levels have not been examined. Furthermore, although animal study suggested that exercise decreased circulating LECT2 levels, it remains unknown whether physical fitness is associated with LECT2 levels in human. We therefore examined the relationship of plasma LECT2 levels with various adiposity indices and cardiorespiratory fitness (CRF) in middle-aged and elderly Japanese men. Furthermore, we examined the relationship of LECT2 levels with the presence of metabolic syndrome, hypertension, insulin resistance and dyslipidemia to determine the clinical significance of measuring circulating LECT2. MATERIALS AND METHODS This was a cross-sectional study of 143 Japanese men (age: 30-79 years). Participants' plasma LECT2 levels were measured by an enzyme-linked immunosorbent assay. To assess their abdominal fat distributions, visceral fat area (VFA) and subcutaneous fat area (SFA) were measured using magnetic resonance imaging. CRF was assessed by measuring peak oxygen uptake ([Formula: see text]). RESULTS All adiposity indices measured in this study were positively correlated with plasma LECT2 levels, while [Formula: see text] was negatively correlated with LECT2 levels after adjustment for age. The correlations, except for VFA were no longer significant with further adjustment for VFA. Stepwise multiple linear regression analysis revealed that VFA was the strongest predictor of plasma LECT2 levels. Plasma LECT2 levels differed based on the presence of metabolic syndrome and dyslipidemia, but not hypertension and insulin resistance. Logistic regression analyses revealed that plasma LECT2 levels were significantly associated with dyslipidemia independently of VFA; VFA was not significantly associated with dyslipidemia after adjustment for LECT2. CONCLUSION VFA was the strongest predictor of plasma LECT2 that is a potential biomarker linking visceral obesity to dyslipidemia.
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28
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Popov DV, Lysenko EA, Butkov AD, Vepkhvadze TF, Perfilov DV, Vinogradova OL. AMPK does not play a requisite role in regulation ofPPARGC1Agene expression via the alternative promoter in endurance-trained human skeletal muscle. Exp Physiol 2017; 102:366-375. [DOI: 10.1113/ep086074] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Accepted: 01/05/2017] [Indexed: 12/25/2022]
Affiliation(s)
- Daniil V. Popov
- Laboratory of Exercise Physiology; Institute of Biomedical Problems of the Russian Academy of Sciences; Moscow Russia
- Faculty of Fundamental Medicine; M. V. Lomonosov Moscow State University; Moscow Russia
| | - Evgeny A. Lysenko
- Laboratory of Exercise Physiology; Institute of Biomedical Problems of the Russian Academy of Sciences; Moscow Russia
- Faculty of Fundamental Medicine; M. V. Lomonosov Moscow State University; Moscow Russia
| | - Alexey D. Butkov
- Laboratory of Exercise Physiology; Institute of Biomedical Problems of the Russian Academy of Sciences; Moscow Russia
| | - Tatiana F. Vepkhvadze
- Laboratory of Exercise Physiology; Institute of Biomedical Problems of the Russian Academy of Sciences; Moscow Russia
| | - Dmitriy V. Perfilov
- Laboratory of Exercise Physiology; Institute of Biomedical Problems of the Russian Academy of Sciences; Moscow Russia
| | - Olga L. Vinogradova
- Laboratory of Exercise Physiology; Institute of Biomedical Problems of the Russian Academy of Sciences; Moscow Russia
- Faculty of Fundamental Medicine; M. V. Lomonosov Moscow State University; Moscow Russia
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29
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Brocca L, Longa E, Cannavino J, Seynnes O, de Vito G, McPhee J, Narici M, Pellegrino MA, Bottinelli R. Human skeletal muscle fibre contractile properties and proteomic profile: adaptations to 3 weeks of unilateral lower limb suspension and active recovery. J Physiol 2016; 593:5361-85. [PMID: 26369674 DOI: 10.1113/jp271188] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2015] [Accepted: 09/04/2015] [Indexed: 01/08/2023] Open
Abstract
KEY POINTS It is generally assumed that muscle fibres go through atrophy following disuse with a loss of specific force and an increase in unloaded shortening velocity. However, the underlying mechanisms remain to be clarified. Most studies have focused on events taking place during the development of disuse, whereas the subsequent recovery phase, which is equally important, has received little attention. Our findings support the hypotheses that the specific force of muscle fibres decreased following unilateral lower limb suspension (ULLS) and returned to normal after 3 weeks of active recovery as a result of a loss and recovery of myosin and actin content. Furthermore, muscle fibres went through extensive qualitative changes in muscle protein pattern following ULLS, and these were reversed by active recovery. Resistance training was very effective in restoring both muscle mass and qualitative muscle changes, indicating that long-term ULLS did not prevent the positive effect of exercise on human muscle. ABSTRACT Following disuse, muscle fibre function goes through adaptations such as a loss of specific force (PO /CSA) and an increase in unloaded shortening velocity, which could be a result of both quantitative changes (i.e. atrophy) and qualitative changes in protein pattern. The underlying mechanisms remain to be clarified. In addition, little is known about the recovery of muscle mass and strength following disuse. In the present study, we report an extensive dataset describing, in detail,the functional and protein content adaptations of skeletal muscle in response to both disuse and re-training. Eight young healthy subjects were subjected to 3 weeks of unilateral lower limb suspension (ULLS), a widely used human model of disuse skeletal muscle atrophy. Needle biopsies samples were taken from the vastus lateralis muscle Pre-ULLS, Post-ULLS and after 3 weeks of recovery during which heavy resistance training was performed. After disuse, cross-sectional area (CSA), PO /CSA and myosin concentration (MC) decreased in both type 1 and 2A skinned muscle fibres. After recovery, CSA and MC returned to levels comparable to those observed before disuse, whereas Po/CSA and unloaded shortening velocity reached a higher level. Myosin heavy chain isoform composition of muscle samples did not differ among the experimental groups. To study the mechanisms underlying such adaptations, a two-dimensional proteomic analysis was performed. ULLS induced a reduction of myofibrillar, metabolic (glycolytic and oxidative) and anti-oxidant defence system protein content. Resistance training was very effective in counteracting ULLS-induced alterations, indicating that long-term ULLS did not prevent the positive effect of exercise on human muscle.
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Affiliation(s)
- Lorenza Brocca
- Department of Molecular Medicine, University of Pavia, Pavia, Italy.,Interuniversity Institute of Myology, University of Pavia, Pavia, Italy
| | - Emanuela Longa
- Department of Molecular Medicine, University of Pavia, Pavia, Italy.,Interdipartimental Centre for Biology and Sport Medicine, University of Pavia, Pavia, Italy
| | | | - Olivier Seynnes
- Institute for Biomedical Research into Human Movement and Health, Manchester Metropolitan University, Manchester, UK.,Norwegian School of Sport Sciences, Oslo, Norway
| | - Giuseppe de Vito
- UCD Institute for Sport and Health, University College Dublin, Dublin, Ireland
| | - Jamie McPhee
- Institute for Biomedical Research into Human Movement and Health, Manchester Metropolitan University, Manchester, UK
| | - Marco Narici
- Institute for Biomedical Research into Human Movement and Health, Manchester Metropolitan University, Manchester, UK.,School of Graduate Entry to Medicine and Health, Division of Clinical Physiology, University of Nottingham, Derby, UK
| | - Maria Antonietta Pellegrino
- Department of Molecular Medicine, University of Pavia, Pavia, Italy.,Interdipartimental Centre for Biology and Sport Medicine, University of Pavia, Pavia, Italy.,Interuniversity Institute of Myology, University of Pavia, Pavia, Italy
| | - Roberto Bottinelli
- Department of Molecular Medicine, University of Pavia, Pavia, Italy.,Fondazione Salvatore Maugeri (IRCCS), Scientific Institute of Pavia, Pavia, Italy
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Abstract
Activation of the adenosine monophosphate (AMP)-activated kinase (AMPK) contributes to beneficial effects such as improvement of the hyperglycemic state in diabetes as well as reduction of obesity and inflammatory processes. Furthermore, stimulation of AMPK activity has been associated with increased exercise capacity. A study published in 2008, directly before the Olympic Games in Beijing, showed that the AMPK activator AICAR (5-amino-1-β-D-ribofuranosyl-imidazole-4-carboxamide) increased the running capacity of mice without any training and thus, prompted the World Anti-Doping Agency (WADA) to include certain AMPK activators in the list of forbidden drugs. This raises the question as to whether all AMPK activators should be considered for registration or whether the increase in exercise performance is only associated with specific AMPK-activating substances. In this review, we intend to shed light on currently published AMPK-activating drugs, their working mechanisms, and their impact on body fitness.
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31
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Understanding Muscle Dysfunction in Chronic Fatigue Syndrome. J Aging Res 2016; 2016:2497348. [PMID: 26998359 PMCID: PMC4779819 DOI: 10.1155/2016/2497348] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Revised: 12/12/2015] [Accepted: 01/13/2016] [Indexed: 12/11/2022] Open
Abstract
Introduction. Chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME) is a debilitating disorder of unknown aetiology, characterised by severe disabling fatigue in the absence of alternative diagnosis. Historically, there has been a tendency to draw psychological explanations for the origin of fatigue; however, this model is at odds with findings that fatigue and accompanying symptoms may be explained by central and peripheral pathophysiological mechanisms, including effects of the immune, oxidative, mitochondrial, and neuronal pathways. For example, patient descriptions of their fatigue regularly cite difficulty in maintaining muscle activity due to perceived lack of energy. This narrative review examined the literature for evidence of biochemical dysfunction in CFS/ME at the skeletal muscle level. Methods. Literature was examined following searches of PUB MED, MEDLINE, and Google Scholar, using key words such as CFS/ME, immune, autoimmune, mitochondria, muscle, and acidosis. Results. Studies show evidence for skeletal muscle biochemical abnormality in CFS/ME patients, particularly in relation to bioenergetic dysfunction. Discussion. Bioenergetic muscle dysfunction is evident in CFS/ME, with a tendency towards an overutilisation of the lactate dehydrogenase pathway following low-level exercise, in addition to slowed acid clearance after exercise. Potentially, these abnormalities may lead to the perception of severe fatigue in CFS/ME.
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32
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Fortifying the Treatment of Prostate Cancer with Physical Activity. Prostate Cancer 2016; 2016:9462975. [PMID: 26977321 PMCID: PMC4764749 DOI: 10.1155/2016/9462975] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Revised: 01/06/2016] [Accepted: 01/11/2016] [Indexed: 11/18/2022] Open
Abstract
Over the past decade, significant data have shown that obese men experience a survival detriment after treatment for prostate cancer. While methods to combat obesity are of utmost importance for the prostate cancer patient, newer data reveal the overall metabolic improvements that accompany increased activity levels and intense exercise beyond weight loss. Along these lines, a plethora of data have shown improvement in prostate cancer-specific outcomes after treatment accompanied with these activity levels. This review discusses the metabolic mechanisms in which increased activity levels and exercise can help improve both outcomes for men treated for prostate cancer while lowering the side effects of treatment.
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33
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Hay J, Wittmeier K, MacIntosh A, Wicklow B, Duhamel T, Sellers E, Dean H, Ready E, Berard L, Kriellaars D, Shen GX, Gardiner P, McGavock J. Physical activity intensity and type 2 diabetes risk in overweight youth: a randomized trial. Int J Obes (Lond) 2015; 40:607-14. [PMID: 26617254 DOI: 10.1038/ijo.2015.241] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/22/2015] [Accepted: 08/13/2015] [Indexed: 11/09/2022]
Abstract
BACKGROUND The chronic effects of high-intensity endurance training on metabolic health outcomes in overweight adolescents remains poorly understood. OBJECTIVE To test the hypothesis that high-intensity endurance training (ET) is superior to moderate-intensity ET for improving risk factors for type 2 diabetes in overweight adolescents. DESIGN AND METHODS In this randomized trial, 106 overweight and obese adolescents (15.2 years; 76% female; 62% Caucasian) were randomly assigned to high-intensity ET (70-85% of heart rate reserve, n=38), moderate-intensity ET (40-55% heart rate reserve; n=32) or control for 6 months (n=36). The primary and secondary outcome measures were insulin sensitivity assessed using a frequently sampled intravenous glucose tolerance test and hepatic triglyceride content with magnetic resonance spectroscopy. Exploratory outcomes were cardiorespiratory fitness, physical activity and MRI and dual x-ray absorptiometry-derived measures of adiposity. RESULTS The study had 96% retention and attendance was 61±21% and 55±24% in the high- and moderate-intensity ET arms. Intention-to-treat analyses revealed that, at follow-up, insulin sensitivity was not different between high-intensity (-1.0 mU kg(-1) min(-1); 95% confidence interval (CI): -1.6, +1.4 mU kg(-1) min(-1)) and moderate-intensity (+0.26 mU kg(-1) min(-1); 95% CI: -1.3, +1.8 mU kg(-1) min(-1)) ET arms compared with controls (interaction, P=0.97). Similarly, hepatic triglyceride at follow-up was not different in high-intensity (-1.7% fat/water (F/W); 95% CI: -7.0, +3.6% F/W) and moderate-intensity (-0.40% FW; 95% CI: -6.0, +5.3% F/W) ET compared with controls. Both high intensity (+4.4 ml per kg-FFM (fat-free mass) per minute; 95% CI: 1.7, 7.1 ml kg-FFM(-1) min(-1)) and moderate intensity (+4.4 ml kg-FFM(-1) min(-1); 95% CI: 1.6, 7.3 ml kg-FFM(-1) min(-1)) increased cardiorespiratory fitness, relative to controls (interaction P<0.001). CONCLUSIONS ET improves cardiorespiratory fitness among obese adolescents; however, owing to lack of compliance, the influence of exercise intensity on insulin sensitivity and hepatic triglycerides remains unclear.
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Affiliation(s)
- J Hay
- Children's Hospital Research Institute of Manitoba, Winnipeg, Manitoba, Canada.,Department of Pediatrics and Child Health, Faculty of Medicine, University of Manitoba, Winnipeg, Manitoba, Canada.,Faculty of Kinesiology and Recreation Management, University of Manitoba, Winnipeg, Manitoba, Canada
| | - K Wittmeier
- Children's Hospital Research Institute of Manitoba, Winnipeg, Manitoba, Canada.,Department of Pediatrics and Child Health, Faculty of Medicine, University of Manitoba, Winnipeg, Manitoba, Canada
| | - A MacIntosh
- Children's Hospital Research Institute of Manitoba, Winnipeg, Manitoba, Canada
| | - B Wicklow
- Children's Hospital Research Institute of Manitoba, Winnipeg, Manitoba, Canada.,Department of Pediatrics and Child Health, Faculty of Medicine, University of Manitoba, Winnipeg, Manitoba, Canada
| | - T Duhamel
- Faculty of Kinesiology and Recreation Management, University of Manitoba, Winnipeg, Manitoba, Canada.,Health, Leisure and Human Performance Research Institute, Winnipeg, Manitoba, Canada.,Department of Physiology, Faculty of Medicine, University of Manitoba, Winnipeg, Manitoba, Canada.,Institute of Cardiovascular Sciences, St. Boniface Research Centre, Winnipeg, Manitoba, Canada
| | - E Sellers
- Children's Hospital Research Institute of Manitoba, Winnipeg, Manitoba, Canada.,Department of Pediatrics and Child Health, Faculty of Medicine, University of Manitoba, Winnipeg, Manitoba, Canada
| | - H Dean
- Children's Hospital Research Institute of Manitoba, Winnipeg, Manitoba, Canada.,Department of Pediatrics and Child Health, Faculty of Medicine, University of Manitoba, Winnipeg, Manitoba, Canada
| | - E Ready
- Faculty of Kinesiology and Recreation Management, University of Manitoba, Winnipeg, Manitoba, Canada.,Health, Leisure and Human Performance Research Institute, Winnipeg, Manitoba, Canada
| | - L Berard
- Diabetes Research Group, Health Sciences Centre of Winnipeg, Winnipeg, Manitoba, Canada
| | - D Kriellaars
- Faculty of Medical Rehabilitation, University of Manitoba, Winnipeg, Manitoba, Canada
| | - G X Shen
- Diabetes Research Group, Health Sciences Centre of Winnipeg, Winnipeg, Manitoba, Canada
| | - P Gardiner
- Faculty of Kinesiology and Recreation Management, University of Manitoba, Winnipeg, Manitoba, Canada.,Health, Leisure and Human Performance Research Institute, Winnipeg, Manitoba, Canada.,Department of Physiology, Faculty of Medicine, University of Manitoba, Winnipeg, Manitoba, Canada
| | - J McGavock
- Children's Hospital Research Institute of Manitoba, Winnipeg, Manitoba, Canada.,Department of Pediatrics and Child Health, Faculty of Medicine, University of Manitoba, Winnipeg, Manitoba, Canada.,Faculty of Kinesiology and Recreation Management, University of Manitoba, Winnipeg, Manitoba, Canada.,Department of Physiology, Faculty of Medicine, University of Manitoba, Winnipeg, Manitoba, Canada
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Prior SJ, Goldberg AP, Ortmeyer HK, Chin ER, Chen D, Blumenthal JB, Ryan AS. Increased Skeletal Muscle Capillarization Independently Enhances Insulin Sensitivity in Older Adults After Exercise Training and Detraining. Diabetes 2015; 64:3386-95. [PMID: 26068543 PMCID: PMC4587640 DOI: 10.2337/db14-1771] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Accepted: 05/23/2015] [Indexed: 01/04/2023]
Abstract
Intramuscular signaling and glucose transport mechanisms contribute to improvements in insulin sensitivity after aerobic exercise training. This study tested the hypothesis that increases in skeletal muscle capillary density (CD) also contribute to exercise-induced improvements in whole-body insulin sensitivity (insulin-stimulated glucose uptake per unit plasma insulin [M/I]) independent of other mechanisms. The study design included a 6-month aerobic exercise training period followed by a 2-week detraining period to eliminate short-term effects of exercise on intramuscular signaling and glucose transport. Before and after exercise training and detraining, 12 previously sedentary older (65 ± 3 years) men and women underwent research tests, including hyperinsulinemic-euglycemic clamps and vastus lateralis biopsies. Exercise training increased Vo2max (2.2 ± 0.2 vs. 2.5 ± 0.2 L/min), CD (313 ± 13 vs. 349 ± 18 capillaries/mm(2)), and M/I (0.041 ± 0.005 vs. 0.051 ± 0.007 μmol/kg fat-free mass/min) (P < 0.05 for all). Exercise training also increased the insulin activation of glycogen synthase by 60%, GLUT4 expression by 16%, and 5' AMPK-α1 expression by 21%, but these reverted to baseline levels after detraining. Conversely, CD and M/I remained 15% and 18% higher after detraining, respectively (P < 0.05), and the changes in M/I (detraining minus baseline) correlated directly with changes in CD in regression analysis (partial r = 0.70; P = 0.02). These results suggest that an increase in CD is one mechanism contributing to sustained improvements in glucose metabolism after aerobic exercise training.
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Affiliation(s)
- Steven J Prior
- Division of Gerontology and Geriatric Medicine, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD Baltimore Veterans Affairs Geriatric Research Education and Clinical Center and Research and Development Service, Baltimore, MD
| | - Andrew P Goldberg
- Division of Gerontology and Geriatric Medicine, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD Baltimore Veterans Affairs Geriatric Research Education and Clinical Center and Research and Development Service, Baltimore, MD
| | - Heidi K Ortmeyer
- Division of Gerontology and Geriatric Medicine, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD Baltimore Veterans Affairs Geriatric Research Education and Clinical Center and Research and Development Service, Baltimore, MD
| | - Eva R Chin
- Department of Kinesiology, University of Maryland School of Public Health, College Park, MD
| | - Dapeng Chen
- Department of Kinesiology, University of Maryland School of Public Health, College Park, MD
| | - Jacob B Blumenthal
- Division of Gerontology and Geriatric Medicine, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD Baltimore Veterans Affairs Geriatric Research Education and Clinical Center and Research and Development Service, Baltimore, MD
| | - Alice S Ryan
- Division of Gerontology and Geriatric Medicine, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD Baltimore Veterans Affairs Geriatric Research Education and Clinical Center and Research and Development Service, Baltimore, MD
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Gordon JW, Dolinsky VW, Mughal W, Gordon GRJ, McGavock J. Targeting skeletal muscle mitochondria to prevent type 2 diabetes in youth. Biochem Cell Biol 2015; 93:452-65. [PMID: 26151290 DOI: 10.1139/bcb-2015-0012] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
The prevalence of type 2 diabetes (T2D) has increased dramatically over the past two decades, not only among adults but also among adolescents. T2D is a systemic disorder affecting every organ system and is especially damaging to the cardiovascular system, predisposing individuals to severe cardiac and vascular complications. The precise mechanisms that cause T2D are an area of active research. Most current theories suggest that the process begins with peripheral insulin resistance that precedes failure of the pancreatic β-cells to secrete sufficient insulin to maintain normoglycemia. A growing body of literature has highlighted multiple aspects of mitochondrial function, including oxidative phosphorylation, lipid homeostasis, and mitochondrial quality control in the regulation of peripheral insulin sensitivity. Whether the cellular mechanisms of insulin resistance in adults are comparable to that in adolescents remains unclear. This review will summarize both clinical and basic studies that shed light on how alterations in skeletal muscle mitochondrial function contribute to whole body insulin resistance and will discuss the evidence supporting high-intensity exercise training as a therapy to circumvent skeletal muscle mitochondrial dysfunction to restore insulin sensitivity in both adults and adolescents.
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Affiliation(s)
- Joseph W Gordon
- a Department of Human Anatomy and Cell Science, College of Nursing, Faculty of Health Sciences, University of Manitoba, The Diabetes Research Envisioned and Accomplished in Manitoba (DREAM) Theme of the Children's Hospital Research Institute of Manitoba, John Buhler Research Centre, 715 McDermot Avenue, Winnipeg, MB R3E 3P4, Canada
| | - Vernon W Dolinsky
- b Department of Pharmacology and Therapeutics, The Diabetes Research Envisioned and Accomplished in Manitoba (DREAM) Theme of the Children's Hospital Research Institute of Manitoba, John Buhler Research Centre, 715 McDermot Avenue, Winnipeg, MB R3E 3P4, Canada
| | - Wajihah Mughal
- c Department of Human Anatomy and Cell Science, The Diabetes Research Envisioned and Accomplished in Manitoba (DREAM) Theme of the Children's Hospital Research Institute of Manitoba, John Buhler Research Centre, 715 McDermot Avenue, Winnipeg, MB R3E 3P4, Canada
| | - Grant R J Gordon
- d Hotchkiss Brain Institute, Health Research Innovation Centre, 3330 Hospital Drive NW, Calgary, AB T2N 4N1, Canada.,e Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Canada
| | - Jonathan McGavock
- f Department of Pediatrics and Child Health, The Diabetes Research Envisioned and Accomplished in Manitoba (DREAM) Theme of the Children's Hospital Research Institute of Manitoba, John Buhler Research Centre, 715 McDermot Avenue, Winnipeg, MB R3E 3P4, Canada
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Kristensen DE, Albers PH, Prats C, Baba O, Birk JB, Wojtaszewski JFP. Human muscle fibre type-specific regulation of AMPK and downstream targets by exercise. J Physiol 2015; 593:2053-69. [PMID: 25640469 DOI: 10.1113/jphysiol.2014.283267] [Citation(s) in RCA: 81] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2014] [Accepted: 01/23/2015] [Indexed: 11/08/2022] Open
Abstract
AMP-activated protein kinase (AMPK) is a regulator of energy homeostasis during exercise. Studies suggest muscle fibre type-specific AMPK expression. However, fibre type-specific regulation of AMPK and downstream targets during exercise has not been demonstrated. We hypothesized that AMPK subunits are expressed in a fibre type-dependent manner and that fibre type-specific activation of AMPK and downstream targets is dependent on exercise intensity. Pools of type I and II fibres were prepared from biopsies of vastus lateralis muscle from healthy men before and after two exercise trials: (1) continuous cycling (CON) for 30 min at 69 ± 1% peak rate of O2 consumption (V̇O2 peak ) or (2) interval cycling (INT) for 30 min with 6 × 1.5 min high-intensity bouts peaking at 95 ± 2% V̇O2 peak . In type I vs. II fibres a higher β1 AMPK (+215%) and lower γ3 AMPK expression (-71%) was found. α1 , α2 , β2 and γ1 AMPK expression was similar between fibre types. In type I vs. II fibres phosphoregulation after CON was similar (AMPK(Thr172) , ACC(Ser221) , TBC1D1(Ser231) and GS(2+2a) ) or lower (TBC1D4(Ser704) ). Following INT, phosphoregulation in type I vs. II fibres was lower (AMPK(Thr172) , TBC1D1(Ser231) , TBC1D4(Ser704) and ACC(Ser221) ) or higher (GS(2+2a) ). Exercise-induced glycogen degradation in type I vs. II fibres was similar (CON) or lower (INT). In conclusion, a differentiated response to exercise of metabolic signalling/effector proteins in human type I and II fibres was evident during interval exercise. This could be important for exercise type-specific adaptations, i.e. insulin sensitivity and mitochondrial density, and highlights the potential for new discoveries when investigating fibre type-specific signalling.
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Affiliation(s)
- Dorte E Kristensen
- Section of Molecular Physiology, Department of Nutrition, Exercise and Sports, August Krogh Centre, University of Copenhagen, Copenhagen, Denmark
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37
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Nicotinic acid increases adiponectin secretion from differentiated bovine preadipocytes through G-protein coupled receptor signaling. Int J Mol Sci 2014; 15:21401-18. [PMID: 25411802 PMCID: PMC4264232 DOI: 10.3390/ijms151121401] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2014] [Revised: 10/20/2014] [Accepted: 11/06/2014] [Indexed: 12/17/2022] Open
Abstract
The transition period in dairy cows (3 weeks prepartum until 3 weeks postpartum) is associated with substantial mobilization of energy stores, which is often associated with metabolic diseases. Nicotinic acid (NA) is an antilipolytic and lipid-lowering compound used to treat dyslipidaemia in humans, and it also reduces non-esterified fatty acids in cattle. In mice the G-protein coupled receptor 109A (GPR109A) ligand NA positively affects the secretion of adiponectin, an important modulator of glucose and fat metabolism. In cattle, the corresponding data linking NA to adiponectin are missing. Our objective was to examine the effects of NA on adiponectin and AMPK protein abundance and the expression of mRNAs of related genes such as chemerin, an adipokine that enhances adiponectin secretion in vitro. Differentiated bovine adipocytes were incubated with pertussis toxin (PTX) to verify the involvement of GPR signaling, and treated with 10 or 15 µM NA for 12 or 24 h. NA increased adiponectin concentrations (p ≤ 0.001) and the mRNA abundances of GPR109A (p ≤ 0.05) and chemerin (p ≤ 0.01). Pre-incubation with PTX reduced the adiponectin response to NA (p ≤ 0.001). The NA-stimulated secretion of adiponectin and the mRNA expression of chemerin in the bovine adipocytes were suggestive of GPR signaling-dependent improved insulin sensitivity and/or adipocyte metabolism in dairy cows.
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38
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Abbott MJ, Turcotte LP. AMPK-α2 is involved in exercise training-induced adaptations in insulin-stimulated metabolism in skeletal muscle following high-fat diet. J Appl Physiol (1985) 2014; 117:869-79. [DOI: 10.1152/japplphysiol.01380.2013] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
AMP-activated protein kinase (AMPK) has been studied extensively and postulated to be a target for the treatment and/or prevention of metabolic disorders such as insulin resistance. Exercise training has been deemed a beneficial treatment for obesity and insulin resistance. Furthermore, exercise is a feasible method to combat high-fat diet (HFD)-induced alterations in insulin sensitivity. The purpose of this study was to determine whether AMPK-α2 activity is required to gain beneficial effects of exercise training with high-fat feeding. Wild-type (WT) and AMPK-α2 dominant-negative (DN) male mice were fed standard diet (SD), underwent voluntary wheel running (TR), fed HFD, or trained with HFD (TR + HFD). By week 6, TR, irrespective of genotype, decreased blood glucose and increased citrate synthase activity in both diet groups and decreased insulin levels in HFD groups. Hindlimb perfusions were performed, and, in WT mice with SD, TR increased insulin-mediated palmitate uptake (76.7%) and oxidation (>2-fold). These training-induced changes were not observed in the DN mice. With HFD, TR decreased palmitate oxidation (61–64%) in both WT and DN and increased palmitate uptake (112%) in the WT with no effects on palmitate uptake in the DN. With SD, TR increased ERK1/2 and JNK1/2 phosphorylation, regardless of genotype. With HFD, TR reduced JNK1/2 phosphorylation, regardless of genotype, carnitine palmitoyltransferase 1 expression in WT, and CD36 expression in both DN and WT. These data suggest that low AMPK-α2 signaling disrupts, in part, the exercise training-induced adaptations in insulin-stimulated metabolism in skeletal muscle following HFD.
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Affiliation(s)
- Marcia J. Abbott
- Department of Biological Sciences, Human and Evolutionary Biology Section, Dana and David Dornsife College of Arts, Letters, and Sciences, University of Southern California, Los Angeles, California; and
- Crean College of Health and Behavioral Sciences, Chapman University, Orange, California
| | - Lorraine P. Turcotte
- Department of Biological Sciences, Human and Evolutionary Biology Section, Dana and David Dornsife College of Arts, Letters, and Sciences, University of Southern California, Los Angeles, California; and
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39
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Dolinsky VW, Dyck JRB. Experimental studies of the molecular pathways regulated by exercise and resveratrol in heart, skeletal muscle and the vasculature. Molecules 2014; 19:14919-47. [PMID: 25237749 PMCID: PMC6271699 DOI: 10.3390/molecules190914919] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2014] [Revised: 09/10/2014] [Accepted: 09/10/2014] [Indexed: 01/07/2023] Open
Abstract
Regular exercise contributes to healthy aging and the prevention of chronic disease. Recent research has focused on the development of molecules, such as resveratrol, that activate similar metabolic and stress response pathways as exercise training. In this review, we describe the effects of exercise training and resveratrol on some of the organs and tissues that act in concert to transport oxygen throughout the body. In particular, we focus on animal studies that investigate the molecular signaling pathways induced by these interventions. We also compare and contrast the effects of exercise and resveratrol in diseased states.
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Affiliation(s)
- Vernon W Dolinsky
- Department of Pharmacology & Therapeutics and the Diabetes Research Envisioned and Accomplished in Manitoba (DREAM) Research Theme of the Manitoba Institute of Child Health, University of Manitoba, 601 John Buhler Research Centre, 715 McDermot Avenue, Winnipeg, MB R3E 3P4, Canada.
| | - Jason R B Dyck
- Department of Pediatrics and the Cardiovascular Research Centre, Mazankowski Alberta Heart Institute, University of Alberta, 458 Heritage Medical Research Centre, Edmonton, AB T6G 2S2, Canada.
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40
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Kitaoka Y, Takahashi Y, Machida M, Takeda K, Takemasa T, Hatta H. Effect of AMPK activation on monocarboxylate transporter (MCT)1 and MCT4 in denervated muscle. J Physiol Sci 2014; 64:59-64. [PMID: 24081524 PMCID: PMC10717869 DOI: 10.1007/s12576-013-0290-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2013] [Accepted: 09/10/2013] [Indexed: 10/26/2022]
Abstract
It is now evident that exercise training leads to increases in monocarboxylate transporter (MCT)1 and MCT4, but little is known about the mechanisms of coupling muscle contraction with these changes. The aim of this study was to investigate the effect of 5-aminoimidazole-4-carboxamide-1-beta-D-ribofuranoside (AICAR) induced activation of AMP-activated protein kinase (AMPK) on MCT1, MCT4, and GLUT4 in denervated muscle. Protein levels of MCT4 and GLUT4 after 10 days of denervation were significantly decreased in mice gastrocnemius muscle, while MCT1 protein levels were not altered. AICAR treatment for 10 days significantly increased MCT4, and GLUT4 protein levels in innervated muscle as shown in previous studies. We found that the MCT1 protein level was also increased in AICAR treated innervated muscle. AICAR treatment prevented the decline in MCT4 and GLUT4 protein levels in denervated muscle. Thus, the current study suggests that MCT1 and MCT4 protein expression in muscles, as well as GLUT4, may be regulated by AMPK-mediated signal pathways, and AMPK activation can prevent denervation-induced decline in MCT4 protein.
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Affiliation(s)
- Yu Kitaoka
- Department of Sports Sciences, The University of Tokyo, Komaba 3-8-1, Meguro-ku, Tokyo, 153-8902 Japan
- Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tennodai 1-1-1, Tsukuba, Ibaraki 305-8574 Japan
| | - Yumiko Takahashi
- Department of Sports Sciences, The University of Tokyo, Komaba 3-8-1, Meguro-ku, Tokyo, 153-8902 Japan
| | - Masanao Machida
- Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tennodai 1-1-1, Tsukuba, Ibaraki 305-8574 Japan
- Research Center for Stem Cell Engineering, National Institute of Advanced Industrial Science and Technology (AIST), Central 4, 1-1-4 Higashi, Tsukuba Science City, 305-8562 Japan
| | - Kohei Takeda
- Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tennodai 1-1-1, Tsukuba, Ibaraki 305-8574 Japan
| | - Tohru Takemasa
- Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tennodai 1-1-1, Tsukuba, Ibaraki 305-8574 Japan
| | - Hideo Hatta
- Department of Sports Sciences, The University of Tokyo, Komaba 3-8-1, Meguro-ku, Tokyo, 153-8902 Japan
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41
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Mortensen B, Friedrichsen M, Andersen NR, Alibegovic AC, Højbjerre L, Sonne MP, Stallknecht B, Dela F, Wojtaszewski JFP, Vaag A. Physical inactivity affects skeletal muscle insulin signaling in a birth weight-dependent manner. J Diabetes Complications 2014; 28:71-8. [PMID: 24120282 DOI: 10.1016/j.jdiacomp.2013.09.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/19/2013] [Revised: 09/03/2013] [Accepted: 09/05/2013] [Indexed: 10/26/2022]
Abstract
AIMS We investigated whether physical inactivity could unmask defects in insulin and AMPK signaling in low birth weight (LBW) subjects. METHODS Twenty LBW and 20 normal birth weight (NBW) subjects were investigated using the euglycemic-hyperinsulinemic clamp with excision of skeletal muscle biopsies pre and post 9days of bed rest. Employing Western blotting, we investigated skeletal muscle Akt, AS160, GLUT4, and AMPK signaling. RESULTS Peripheral insulin action was similar in the two groups and was decreased to the same extent post bed rest. Insulin and AMPK signaling was unaffected by bed rest in NBW individuals. LBW subjects showed decreased insulin-stimulated Akt phosphorylation and increased AMPK α1 and γ3 protein expression post bed rest. Insulin response of AS160 phosphorylation was lower in LBW subjects both pre and post bed rest. CONCLUSIONS Bed rest-induced insulin resistance is not explained by impaired muscle insulin or AMPK signaling in subjects with or without LBW. Lower muscle insulin signaling in LBW subjects post bed rest despite similar degree of insulin resistance as seen in controls may to some extent support the idea that LBW subjects are at higher risk of developing type 2 diabetes when being physically inactive.
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Affiliation(s)
- Brynjulf Mortensen
- Steno Diabetes Center, Gentofte, Denmark; Molecular Physiology Group, The August Krogh Centre, Department of Nutrition, Exercise and Sports, University of Copenhagen.
| | - Martin Friedrichsen
- Steno Diabetes Center, Gentofte, Denmark; Molecular Physiology Group, The August Krogh Centre, Department of Nutrition, Exercise and Sports, University of Copenhagen
| | - Nicoline R Andersen
- Molecular Physiology Group, The August Krogh Centre, Department of Nutrition, Exercise and Sports, University of Copenhagen
| | | | - Lise Højbjerre
- Department of Biomedical Sciences, University of Copenhagen; Center for Healthy Ageing, University of Copenhagen
| | - Mette P Sonne
- Department of Biomedical Sciences, University of Copenhagen; Center for Healthy Ageing, University of Copenhagen
| | | | - Flemming Dela
- Department of Biomedical Sciences, University of Copenhagen; Center for Healthy Ageing, University of Copenhagen
| | - Jørgen F P Wojtaszewski
- Molecular Physiology Group, The August Krogh Centre, Department of Nutrition, Exercise and Sports, University of Copenhagen
| | - Allan Vaag
- Steno Diabetes Center, Gentofte, Denmark; Rigshospitalet, Department of Endocrinology, Denmark
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Swick LL, Kazgan N, Onyenwoke RU, Brenman JE. Isolation of AMP-activated protein kinase (AMPK) alleles required for neuronal maintenance in Drosophila melanogaster. Biol Open 2013; 2:1321-3. [PMID: 24337116 PMCID: PMC3863416 DOI: 10.1242/bio.20136775] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The maintenance of energetic homeostasis in the face of limited available nutrients is a complex problem faced by all organisms. One important mechanism to maintain energetic homeostasis involves the activation of the energy sensor AMP-activated protein kinase (AMPK). AMPK is a cell-autonomous energy sensor that is highly sensitive to and regulated by the ATP to ADP and ATP to AMP ratios. However, the genetic analysis of AMPK signaling in vertebrates has been complicated by the existence of multiple redundant AMPK subunits. Here, we describe the identification of mutations in the single Drosophila melanogaster AMPK catalytic subunit (AMPKα) and their implications for neural maintenance and integrity. This article provides a citation replacement for previously published ampkα alleles, transgenes and neuronal phenotypes, which remain accurate; however, they were used in a previously published study that has subsequently been retracted (Mirouse et al., 2013).
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Affiliation(s)
- Lance L Swick
- Department of Cell Biology and Physiology, and Neuroscience Center, University of North Carolina-Chapel Hill School of Medicine, Chapel Hill, NC 27599, USA
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43
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Kostovski E, Boon H, Hjeltnes N, Lundell LS, Ahlsén M, Chibalin AV, Krook A, Iversen PO, Widegren U. Altered content of AMP-activated protein kinase isoforms in skeletal muscle from spinal cord injured subjects. Am J Physiol Endocrinol Metab 2013; 305:E1071-80. [PMID: 24022865 DOI: 10.1152/ajpendo.00132.2013] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
AMP-activated protein kinase (AMPK) is a pivotal regulator of energy homeostasis. Although downstream targets of AMPK are widely characterized, the physiological factors governing isoform expression of this protein kinase are largely unknown. Nerve/contractile activity has a major impact on the metabolic phenotype of skeletal muscle, therefore likely to influence AMPK isoform expression. Spinal cord injury represents an extreme form of physical inactivity, with concomitant changes in skeletal muscle metabolism. We assessed the influence of longstanding and recent spinal cord injury on protein abundance of AMPK isoforms in human skeletal muscle. We also determined muscle fiber type as a marker of glycolytic or oxidative metabolism. In subjects with longstanding complete injury, protein abundance of the AMPKγ3 subunit, as well as myosin heavy chain (MHC) IIa and IIx, were increased, whereas abundance of the AMPKγ1 subunit and MHC I were decreased. Similarly, abundance of AMPKγ3 and MHC IIa proteins were increased, whereas AMPKα2, -β1, and -γ1 subunits and MHC I abundance was decreased during the first year following injury, reflecting a more glycolytic phenotype of the skeletal muscle. However, in incomplete cervical lesions, partial recovery of muscle function attenuated the changes in the isoform profile of AMPK and MHC. Furthermore, exercise training (electrically stimulated leg cycling) partly normalized mRNA expression of AMPK isoforms. Thus, physical activity affects the relative expression of AMPK isoforms. In conclusion, skeletal muscle abundance of AMPK isoforms is related to physical activity and/or muscle fiber type. Thus, physical/neuromuscular activity is an important determinant of isoform abundance of AMPK and MCH. This further underscores the need for physical activity as part of a treatment regimen after spinal cord injury to maintain skeletal muscle metabolism.
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Affiliation(s)
- Emil Kostovski
- Section for Spinal Cord Injury, Sunnaas Rehabilitation Hospital, Nesoddtangen, Norway
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Wu J, Puppala D, Feng X, Monetti M, Lapworth AL, Geoghegan KF. Chemoproteomic analysis of intertissue and interspecies isoform diversity of AMP-activated protein kinase (AMPK). J Biol Chem 2013; 288:35904-12. [PMID: 24187138 DOI: 10.1074/jbc.m113.508747] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
AMP-activated protein kinase (AMPK) is a heterotrimeric enzyme that senses and governs changes in the cellular energy balance represented by concentrations of AMP, ADP, and ATP. Each of its three chains (α, β, and γ) exists as either two or three subtypes, theoretically allowing up to 12 different forms of the complete enzyme. Tissue specificity in the distribution of AMPK subtypes is believed to underpin a range of biological functions for AMPK, a central regulator of metabolic function and response. It is of particular interest for drug discovery purposes to compare AMPK isoforms that are most prevalent in human liver and muscle with isoforms present in key preclinical species. To complement immunocapture/immunodetection methods, which for AMPK are challenged by sequence similarities and difficulties of obtaining accurate relative quantitation, AMPK was captured from lysates of a range of cells and tissues using the ActivX ATP probe. This chemical probe covalently attaches desthiobiotin to one or more conserved lysyl residues in the ATP-binding sites of protein kinases, including AMPK, while also labeling a wide range of ATP-utilizing proteins. Affinity-based recovery of labeled proteins followed by gel-based fractionation of the captured sample was followed by proteomic characterization of AMPK polypeptides. In agreement with transcript-based analysis and previous indications from immunodetection, the results indicated that the predominant AMPK heterotrimer in human liver is α1β2γ1 but that dog and rat livers mainly contain the α1β1γ1 and α2β1γ1 forms, respectively. Differences were not detected between the AMPK profiles of normal and diabetic human liver tissues.
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Affiliation(s)
- Jiang Wu
- From Pfizer Worldwide Research, Groton, Connecticut 06340 and
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45
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Mortensen B, Hingst JR, Frederiksen N, Hansen RWW, Christiansen CS, Iversen N, Friedrichsen M, Birk JB, Pilegaard H, Hellsten Y, Vaag A, Wojtaszewski JFP. Effect of birth weight and 12 weeks of exercise training on exercise-induced AMPK signaling in human skeletal muscle. Am J Physiol Endocrinol Metab 2013; 304:E1379-90. [PMID: 23612997 DOI: 10.1152/ajpendo.00295.2012] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Subjects with a low birth weight (LBW) display increased risk of developing type 2 diabetes (T2D). We hypothesized that this is associated with defects in muscle adaptations following acute and regular physical activity, evident by impairments in the exercise-induced activation of AMPK signaling. We investigated 21 LBW and 21 normal birth weight (NBW) subjects during 1 h of acute exercise performed at the same relative workload before and after 12 wk of exercise training. Multiple skeletal muscle biopsies were obtained before and after exercise. Protein levels and phosphorylation status were determined by Western blotting. AMPK activities were measured using activity assays. Protein levels of AMPKα1 and -γ1 were significantly increased, whereas AMPKγ3 levels decreased with training independently of group. The LBW group had higher exercise-induced AMPK Thr(172) phosphorylation before training and higher exercise-induced ACC2 Ser(221) phosphorylation both before and after training compared with NBW. Despite exercise being performed at the same relative intensity (65% of Vo2peak), the acute exercise response on AMPK Thr(172), ACC2 Ser(221), AMPKα2β2γ1, and AMPKα2β2γ3 activities, GS activity, and adenine nucleotides as well as hexokinase II mRNA levels were all reduced after exercise training. Increased exercise-induced muscle AMPK activation and ACC2 Ser(221) phosphorylation in LBW subjects may indicate a more sensitive AMPK system in this population. Long-term exercise training may reduce the need for AMPK to control energy turnover during exercise. Thus, the remaining γ3-associated AMPK activation by acute exercise after exercise training might be sufficient to maintain cellular energy balance.
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Chen S, An J, Lian L, Qu L, Zheng J, Xu G, Yang N. Polymorphisms in AKT3, FIGF, PRKAG3, and TGF-β genes are associated with myofiber characteristics in chickens. Poult Sci 2013; 92:325-30. [PMID: 23300296 DOI: 10.3382/ps.2012-02766] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Muscle characteristics such as myofiber diameter, density, and total number are important traits in broiler breeding and production. In the present study, 19 SNP of 13 major genes, which are located in the vicinity of quantitative trait loci affecting breast muscle weight, including INS, IGF2, PIK3C2A, AKT3, PRKAB2, PRKAG3, VEGFA, RPS6KA2/3, FIGF, and TGF-β1/2/3, were chosen to be genotyped by high-throughput matrix-assisted laser desorption/ionization time-of-flight mass spectrometry in a broiler population. One hundred twenty birds were slaughtered at 6 wk of age. Body weight, breast muscle weight, myofiber diameter, density, and total number were determined for each bird. Six SNP with a very low minor allele frequency (<1%) were excluded for further analysis. The remaining 13 SNP were used for the association study with muscle characteristics. The results showed that SNP in TGF-β1/2/3 had significant effects on myofiber diameter. A SNP in PRKAG3 had a significant effect on myofiber density (P < 0.05). A C > G mutation in FIGF was strongly associated with total fiber number (P < 0.05). Additionally, birds with the GG genotype of the C > G mutation in AKT3 had significantly larger myofiber numbers (P < 0.05) than birds with the CC or GC genotype. The SNP identified in the present study might be used as potential markers in broiler breeding.
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Affiliation(s)
- Sirui Chen
- National Engineering Laboratory for Animal Breeding and MOA Key Laboratory of Animal Genetics and Breeding, College of Animal Science and Technology, China Agricultural University, Beijing 100193, China
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Friedrichsen M, Mortensen B, Pehmøller C, Birk JB, Wojtaszewski JFP. Exercise-induced AMPK activity in skeletal muscle: role in glucose uptake and insulin sensitivity. Mol Cell Endocrinol 2013; 366:204-14. [PMID: 22796442 DOI: 10.1016/j.mce.2012.06.013] [Citation(s) in RCA: 107] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/19/2012] [Accepted: 06/21/2012] [Indexed: 12/25/2022]
Abstract
The energy/fuel sensor 5'-AMP-activated protein kinase (AMPK) is viewed as a master regulator of cellular energy balance due to its many roles in glucose, lipid, and protein metabolism. In this review we focus on the regulation of AMPK activity in skeletal muscle and its involvement in glucose metabolism, including glucose transport and glycogen synthesis. In addition, we discuss the plausible interplay between AMPK and insulin signaling regulating these processes.
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Affiliation(s)
- Martin Friedrichsen
- Molecular Physiology Group, The August Krogh Centre, Department of Exercise and Sport Sciences, University of Copenhagen, Denmark
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Bartlett JD, Louhelainen J, Iqbal Z, Cochran AJ, Gibala MJ, Gregson W, Close GL, Drust B, Morton JP. Reduced carbohydrate availability enhances exercise-induced p53 signaling in human skeletal muscle: implications for mitochondrial biogenesis. Am J Physiol Regul Integr Comp Physiol 2013; 304:R450-8. [PMID: 23364526 DOI: 10.1152/ajpregu.00498.2012] [Citation(s) in RCA: 103] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
The mechanisms that regulate the enhanced skeletal muscle oxidative capacity observed when training with reduced carbohydrate (CHO) availability are currently unknown. The aim of the present study was to test the hypothesis that reduced CHO availability enhances p53 signaling and expression of genes associated with regulation of mitochondrial biogenesis and substrate utilization in human skeletal muscle. In a repeated-measures design, muscle biopsies (vastus lateralis) were obtained from eight active males before and after performing an acute bout of high-intensity interval running with either high (HIGH) or low CHO availability (LOW). Resting muscle glycogen (HIGH, 467 ± 19; LOW, 103 ± 9 mmol/kg dry wt) was greater in HIGH compared with LOW (P < 0.05). Phosphorylation (P-) of ACC(Ser79) (HIGH, 1.4 ± 0.4; LOW, 2.9 ± 0.9) and p53(Ser15) (HIGH, 0.9 ± 0.4; LOW, 2.6 ± 0.8) was higher in LOW immediately postexercise and 3 h postexercise, respectively (P < 0.05). Before and 3 h postexercise, mRNA content of pyruvate dehydrogenase kinase 4, mitochondrial transcription factor A, cytochrome-c oxidase IV, and PGC-1α were greater in LOW compared with HIGH (P < 0.05), whereas carnitine palmitoyltransferase-1 showed a trend toward significance (P = 0.09). However, only PGC-1α expression was increased by exercise (P < 0.05), where three-fold increases occurred independently of CHO availability. We conclude that the exercise-induced increase in p53 phosphorylation is enhanced in conditions of reduced CHO availability, which may be related to upstream signaling through AMPK. Given the emergence of p53 as a molecular regulator of mitochondrial biogenesis, such nutritional modulation of contraction-induced p53 activation has implications for both athletic and clinical populations.
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Affiliation(s)
- Jonathan D Bartlett
- Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, United Kingdom
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Hellyer NJ, Nokleby JJ, Thicke BM, Zhan WZ, Sieck GC, Mantilla CB. Reduced ribosomal protein s6 phosphorylation after progressive resistance exercise in growing adolescent rats. J Strength Cond Res 2012; 26:1657-66. [PMID: 22614147 DOI: 10.1519/jsc.0b013e318231abc9] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The purpose of this study was to investigate moderate intensity progressive resistance exercise (PRE) in growing adolescent rats and its effect on muscle hypertrophy (defined as an increase in fiber cross-sectional area [CSA]). We hypothesized that in adolescent animals moderate intensity PRE would increase (a) fiber CSA; (b) myosin heavy chain (MyHC) content; and (c) expression and phosphorylation of cell signaling molecules involved in translational regulation, compared with that in age-matched sedentary (SED) controls. In the PRE group, 3-week-old male rats were trained to climb a vertical ladder as a mode of PRE training such that by 10 weeks all animals in the PRE group had progressed to carry an additional 80% of their body weight per climb. In agreement with our hypotheses, we observed that 10 weeks of moderate PRE in adolescent animals was sufficient to increase the CSA of muscle fibers and increase MyHC content. The average muscle fiber CSA increased by >10%, and the total MyHC content increased by 35% (p < 0.05) in the PRE group compared with that in the SED animals. Concurrently, we investigated sustained changes in the expression and phosphorylation of key signaling molecules that are previously identified regulators of hypertrophy in adult animal models. Contrary to our hypotheses, expression and phosphorylation of the translational regulators mammalian target of rapamycin and Akt were not increased in the PRE group. In addition, we observed that the ratio of phosphorylated-to-unphosphorylated ribosomal protein S6 (rpS6) was reduced over sixfold in PRE animals (p < 0.05) and that total rpS6 protein levels were unchanged between PRE and SED animals (p > 0.05). We conclude that moderate intensity PRE is sufficient to induce muscle hypertrophy in adolescent animals, whereas the signaling mechanisms associated with muscle hypertrophy may differ between growing adolescents and adults.
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Affiliation(s)
- Nathan J Hellyer
- Department of Physical Medicine and Rehabilitation, Mayo Clinic, Rochester, Minnesota, USA.
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Dolinsky VW, Jones KE, Sidhu RS, Haykowsky M, Czubryt MP, Gordon T, Dyck JRB. Improvements in skeletal muscle strength and cardiac function induced by resveratrol during exercise training contribute to enhanced exercise performance in rats. J Physiol 2012; 590:2783-99. [PMID: 22473781 DOI: 10.1113/jphysiol.2012.230490] [Citation(s) in RCA: 119] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Exercise training (ET) improves endurance capacity by increasing both skeletal muscle mitochondrial number and function, as well as contributing to favourable cardiac remodelling.Interestingly, some of the benefits of regular exercise can also be mimicked by the naturally occurring polyphenol, resveratrol (RESV). However, it is not known whether RESV enhances physiological adaptations to ET. To investigate this, male Wistar rats were randomly assigned to a control chow diet or a chow diet that contained RESV (4 g kg⁻¹ of diet) and subsequently subjected to a programme of progressive treadmill running for 12 weeks. ET-induced improvements in exercise performance were enhanced by 21% (P <0.001) by the addition of RESV to the diet. In soleus muscle, ET+RESV increased both the twitch (1.8-fold; P <0.05) and tetanic(1.2-fold; P <0.05) forces generated during isometric contraction, compared to ET alone. In vivo echocardiography demonstrated that ET+RESV also increased the resting left ventricular ejection fraction by 10% (P <0.05), and reduced left ventricular wall stress compared to ET alone.These functional changes were accompanied by increased cardiac fatty acid oxidation (1.2-fold;P <0.05) and favourable changes in cardiac gene expression and signal transduction pathways that optimized the utilization of fatty acids in ET+RESV compared to ET alone. Overall, our findings provide evidence that the capacity for fatty acid oxidation is augmented by the addition of RESV to the diet during ET, and that this may contribute to the improved physical performance of rats following ET.
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Affiliation(s)
- Vernon W Dolinsky
- Cardiovascular Research Centre, Mazankowski Alberta Heart Institute, Department of Pediatrics, University of Alberta, Edmonton, AB, Canada
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