scholarly journals Critical role for free radicals on sprint exercise-induced CaMKII and AMPKα phosphorylation in human skeletal muscle

2013 ◽  
Vol 114 (5) ◽  
pp. 566-577 ◽  
Author(s):  
David Morales-Alamo ◽  
Jesús Gustavo Ponce-González ◽  
Amelia Guadalupe-Grau ◽  
Lorena Rodríguez-García ◽  
Alfredo Santana ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Protein Kinase ◽  
Energy Demand ◽  
Human Skeletal Muscle ◽  
Critical Role ◽  
Recovery Period ◽  
Muscle Metabolism ◽  
High Energy ◽  
Vastus Lateralis Muscle ◽  
Sprint Exercise

The extremely high energy demand elicited by sprint exercise is satisfied by an increase in O2 consumption combined with a high glycolytic rate, leading to a marked lactate accumulation, increased AMP-to-ATP ratio, and reduced NAD+/NADH.H+ and muscle pH, which are accompanied by marked Thr172 AMP-activated protein kinase (AMPK)-α phosphorylation during the recovery period by a mechanism not fully understood. To determine the role played by reactive nitrogen and oxygen species (RNOS) on Thr172-AMPKα phosphorylation in response to cycling sprint exercise, nine voluntary participants performed a single 30-s sprint (Wingate test) on two occasions: one 2 h after the ingestion of placebo and another after the intake of antioxidants (α-lipoic acid, vitamin C, and vitamin E) in a double-blind design. Vastus lateralis muscle biopsies were obtained before, immediately postsprint, and 30 and 120 min postsprint. Performance and muscle metabolism were similar during both sprints. The NAD+-to-NADH.H+ ratio was similarly reduced (84%) and the AMP-to-ATP ratio was similarly increased (×21-fold) immediately after the sprints. Thr286 Ca2+/calmodulin-dependent protein kinase II (CaMKII) and Thr172-AMPKα phosphorylations were increased after the control sprint (with placebo) but not when the sprints were preceded by the ingestion of antioxidants. Ser485-AMPKα1/Ser491-AMPKα2 phosphorylation, a known inhibitory mechanism of Thr172-AMPKα phosphorylation, was increased only with antioxidant ingestion. In conclusion, RNOS play a crucial role in AMPK-mediated signaling after sprint exercise in human skeletal muscle. Antioxidant ingestion 2 h before sprint exercise abrogates the Thr172-AMPKα phosphorylation response observed after the ingestion of placebo by reducing CaMKII and increasing Ser485-AMPKα1/Ser491-AMPKα2 phosphorylation. Sprint performance, muscle metabolism, and AMP-to-ATP and NAD+-to-NADH.H+ ratios are not affected by the acute ingestion of antioxidants.

Eccentric exercise markedly increases c-Jun NH2-terminal kinase activity in human skeletal muscle

1999 ◽  
Vol 87 (5) ◽  
pp. 1668-1673 ◽  
Author(s):  
Marni D. Boppart ◽  
Doron Aronson ◽  
Lindsay Gibson ◽  
Ronenn Roubenoff ◽  
Leslie W. Abad ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Protein Kinase ◽  
Eccentric Exercise ◽  
Intracellular Signaling ◽  
Human Skeletal Muscle ◽  
Vastus Lateralis ◽  
Fold Increase ◽  
Mitogen Activated Protein Kinase ◽  
Eccentric Contractions ◽  
Vastus Lateralis Muscle

Eccentric contractions require the lengthening of skeletal muscle during force production and result in acute and prolonged muscle injury. Because a variety of stressors, including physical exercise and injury, can result in the activation of the c-Jun NH2-terminal kinase (JNK) intracellular signaling cascade in skeletal muscle, we investigated the effects of eccentric exercise on the activation of this stress-activated protein kinase in human skeletal muscle. Twelve healthy subjects (7 men, 5 women) completed maximal concentric or eccentric knee extensions on a KinCom isokinetic dynamometer (10 sets, 10 repetitions). Percutaneous needle biopsies were obtained from the vastus lateralis muscle 24 h before exercise (basal), immediately postexercise, and 6 h postexercise. Whereas both forms of exercise increased JNK activity immediately postexercise, eccentric contractions resulted in a much higher activation (15.4 ± 4.5 vs. 3.5 ± 1.4-fold increase above basal, eccentric vs. concentric). By 6 h after exercise, JNK activity decreased back to baseline values. In contrast to the greater activation of JNK with eccentric exercise, the mitogen-activated protein kinase kinase 4, the immediate upstream regulator of JNK, was similarly activated by concentric and eccentric exercise. Because the activation of JNK promotes the phosphorylation of a variety of transcription factors, including c-Jun, the results from this study suggest that JNK may be involved in the molecular and cellular adaptations that occur in response to injury-producing exercise in human skeletal muscle.

scholarly journals Skeletal muscle signaling, metabolism, and performance during sprint exercise in severe acute hypoxia after the ingestion of antioxidants

2017 ◽  
Vol 123 (5) ◽  
pp. 1235-1245 ◽  
Author(s):  
David Morales-Alamo ◽  
Borja Guerra ◽  
Jesús Gustavo Ponce-González ◽  
Amelia Guadalupe-Grau ◽  
Alfredo Santana ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Protein Kinase ◽  
Transforming Growth Factor ◽  
Vastus Lateralis ◽  
Acute Hypoxia ◽  
Molar Ratio ◽  
Vastus Lateralis Muscle ◽  
Sprint Exercise ◽  
Amp Activated Protein Kinase ◽  
Glycolytic Rate

The aim of this study was to determine if reactive oxygen species (ROS) could play a role in blunting Thr172-AMP-activated protein kinase (AMPK)-α phosphorylation in human skeletal muscle after sprint exercise in hypoxia and to elucidate the potential signaling mechanisms responsible for this response. Nine volunteers performed a single 30-s sprint (Wingate test) in two occasions while breathing hypoxic gas ([Formula: see text] = 75 mmHg): one after the ingestion of placebo and another following the intake of antioxidants (α-lipoic acid, vitamin C, and vitamin E), with a randomized double-blind design. Vastus lateralis muscle biopsies were obtained before, immediately after, and 30- and 120-min postsprint. Compared with the control condition, the ingestion of antioxidants resulted in lower plasma carbonylated proteins, attenuated elevation of the AMP-to-ATP molar ratio, and reduced glycolytic rate ( P < 0.05) without significant effects on performance or V̇o2. The ingestion of antioxidants did not alter the basal muscle signaling. Thr172-AMPKα and Thr184/187-transforming growth factor-β-activated kinase 1 (TAK1) phosphorylation were not increased after the sprint regardless of the ingestion of antioxidants. Thr286-CaMKII phosphorylation was increased after the sprint, but this response was blunted by the antioxidants. Ser485-AMPKα1/Ser491-AMPKα2 phosphorylation increased immediately after the sprints coincident with increased Akt phosphorylation. In summary, antioxidants attenuate the glycolytic response to sprint exercise in severe acute hypoxia and modify the muscle signaling response to exercise. Ser485-AMPKα1/Ser491-AMPKα2 phosphorylation, a known mechanism of Thr172-AMPKα phosphorylation inhibition, is increased immediately after sprint exercise in hypoxia, probably by a mechanism independent of ROS. NEW & NOTEWORTHY The glycolytic rate is increased during sprint exercise in severe acute hypoxia. This study showed that the ingestion of antioxidants before sprint exercise in severe acute hypoxia reduced the glycolytic rate and attenuated the increases of the AMP-to-ATP and the reduction of the NAD+-to-NADH.H+ ratios. This resulted in a modified muscle signaling response with a blunted Thr286-CaMKII but similar AMP-activated protein kinase phosphorylation responses in the sprints preceded by the ingestion of antioxidants.

scholarly journals Training state and skeletal muscle autophagy in response to 36 h of fasting

2018 ◽  
Vol 125 (5) ◽  
pp. 1609-1619 ◽  
Author(s):  
Maja Munk Dethlefsen ◽  
Lærke Bertholdt ◽  
Anders Gudiksen ◽  
Tomasz Stankiewicz ◽  
Jens Bangsbo ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Amino Acids ◽  
Protein Kinase ◽  
Human Skeletal Muscle ◽  
Vastus Lateralis ◽  
Adaptor Protein ◽  
Vastus Lateralis Muscle ◽  
Trained Subjects ◽  
Lateralis Muscle ◽  
Training State

The present study aimed at investigating fasting-induced responses in regulators and markers of autophagy in vastus lateralis muscle from untrained and trained human subjects. Untrained and trained subjects (based on maximum oxygen uptake, muscle citrate synthase activity, and oxidative phosphorylation protein level) fasted for 36 h with vastus lateralis muscle biopsies obtained at 2, 12, 24, and 36 h after a standardized meal. Fasting reduced ( P < 0.05) skeletal muscle microtubule-associated protein-1A/1B light chain 3 (LC3)I, LC3II, and adaptor protein sequestosome 1/p62 protein content in untrained subjects only. Moreover, skeletal muscle RAC-alpha serine/threonine-protein kinase (AKT)Thr308, AMP-activated protein kinase (AMPK)Thr172, and Unc-51-like autophagy-activating kinase-1 (ULK1)Ser555 phosphorylation state, as well as Bcl-2-interacting coiled-coil protein-1 (Beclin1) and ULK1Ser757 phosphorylation, was lower ( P < 0.05) in trained than untrained subjects during fasting. In addition, the plasma concentrations of several amino acids were higher ( P < 0.05) in trained than untrained subjects, and the plasma concentration profile of several amino acids was different in untrained and trained subjects during fasting. Taken together, these findings suggest that 36-h fasting has effects on some mediators of autophagy in untrained human skeletal muscle and that training state influences the effect of fasting on autophagy signaling and on mediators of autophagy in skeletal muscle. NEW & NOTEWORTHY This study showed that skeletal muscle autophagy was only modestly affected in humans by 36 h of fasting. Hence, 36-h fasting has effects on some mediators of autophagy in untrained human skeletal muscle, and training state influences the effect of fasting on autophagy signaling and on mediators of autophagy in skeletal muscle.

Transcriptional regulation of gene expression in human skeletal muscle during recovery from exercise

2000 ◽  
Vol 279 (4) ◽  
pp. E806-E814 ◽  
Author(s):  
Henriette Pilegaard ◽  
George A. Ordway ◽  
Bengt Saltin ◽  
P. Darrell Neufer
Keyword(s):  
Skeletal Muscle ◽  
Exercise Training ◽  
Human Skeletal Muscle ◽  
Molecular Mechanisms ◽  
Uncoupling Protein ◽  
Pyruvate Dehydrogenase Kinase ◽  
Heme Oxygenase 1 ◽  
Metabolic Efficiency ◽  
Vastus Lateralis Muscle ◽  
Mrna Levels

Exercise training elicits a number of adaptive changes in skeletal muscle that result in an improved metabolic efficiency. The molecular mechanisms mediating the cellular adaptations to exercise training in human skeletal muscle are unknown. To test the hypothesis that recovery from exercise is associated with transcriptional activation of specific genes, six untrained male subjects completed 60–90 min of exhaustive one-legged knee extensor exercise for five consecutive days. On day 5, nuclei were isolated from biopsies of the vastus lateralis muscle of the untrained and the trained leg before exercise and from the trained leg immediately after exercise and after 15 min, 1 h, 2 h, and 4 h of recovery. Transcriptional activity of the uncoupling protein 3 (UCP3), pyruvate dehydrogenase kinase 4 (PDK4), and heme oxygenase-1 (HO-1) genes (relative to β-actin) increased by three- to sevenfold in response to exercise, peaking after 1–2 h of recovery. Increases in mRNA levels followed changes in transcription, peaking between 2 and 4 h after exercise. Lipoprotein lipase and carnitine pamitoyltransferase I gene transcription and mRNA levels showed similar but less dramatic induction patterns, with increases ranging from two- to threefold. In a separate study, a single 4-h bout of cycling exercise ( n = 4) elicited from 5 to >20-fold increases in UCP3, PDK4, and HO-1 transcription, suggesting that activation of these genes may be related to the duration or intensity of exercise. These data demonstrate that exercise induces transient increases in transcription of metabolic genes in human skeletal muscle. Moreover, the findings suggest that the cumulative effects of transient increases in transcription during recovery from consecutive bouts of exercise may represent the underlying kinetic basis for the cellular adaptations associated with exercise training.

RPS6 phosphorylation occurs to a greater extent in the periphery of human skeletal muscle fibers, near focal adhesions, after anabolic stimuli

2021 ◽  
Author(s):  
Nathan Hodson ◽  
Michael Mazzulla ◽  
Maksym N. H. Holowaty ◽  
Dinesh Kumbhare ◽  
Daniel R. Moore
Keyword(s):  
Skeletal Muscle ◽  
Focal Adhesion ◽  
Human Skeletal Muscle ◽  
Muscle Fibers ◽  
Focal Adhesions ◽  
Immunofluorescent Staining ◽  
Whole Body ◽  
Vastus Lateralis Muscle ◽  
Cell Periphery ◽  
Rps6 Phosphorylation

Following anabolic stimuli (mechanical loading and/or amino acid provision) the mechanistic target of rapamycin complex 1 (mTORC1), a master regulator of protein synthesis, translocates toward the cell periphery. However, it is unknown if mTORC1-mediated phosphorylation events occur in these peripheral regions or prior to translocation (i.e. in central regions). We therefore aimed to determine the cellular location of a mTORC1-mediated phosphorylation event, RPS6Ser240/244, in human skeletal muscle following anabolic stimuli. Fourteen young, healthy males either ingested a protein-carbohydrate beverage (0.25g/kg protein, 0.75g/kg carbohydrate) alone (n=7;23±5yrs;76.8±3.6kg;13.6±3.8%BF, FED) or following a whole-body resistance exercise bout (n=7;22±2yrs;78.1±3.6kg;12.2±4.9%BF, EXFED). Vastus lateralis muscle biopsies were obtained at rest (PRE) and 120 and 300min following anabolic stimuli. RPS6Ser240/244 phosphorylation measured by immunofluorescent staining or immunoblot was positively correlated (r=0.76, p<0.001). Peripheral staining intensity of p-RPS6Ser240/244 increased above PRE in both FED and EXFED at 120min (~54% and ~138% respectively, p<0.05) but was greater in EXFED at both post-stimuli time points (p<0.05). The peripheral-central ratio of p-RPS6240/244 staining displayed a similar pattern, even when corrected for total RPS6 distribution, suggesting RPS6 phosphorylation occurs to a greater extent in the periphery of fibers. Moreover, p-RPS6Ser240/244 intensity within paxillin-positive regions, a marker of focal adhesion complexes, was elevated at 120min irrespective of stimulus (p=0.006) before returning to PRE at 300min. These data confirm that RPS6Ser240/244 phosphorylation occurs in the region of human muscle fibers to which mTOR translocates following anabolic stimuli and identifies focal adhesion complexes as a potential site of mTORC1 regulation in vivo.

Sprint training increases human skeletal muscle Na(+)-K(+)-ATPase concentration and improves K+ regulation

1993 ◽  
Vol 75 (1) ◽  
pp. 173-180 ◽  
Author(s):  
M. J. McKenna ◽  
T. A. Schmidt ◽  
M. Hargreaves ◽  
L. Cameron ◽  
S. L. Skinner ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Binding Site ◽  
Intermittent Exercise ◽  
Recovery Period ◽  
Muscle Performance ◽  
Vastus Lateralis Muscle ◽  
Work Output ◽  
Sprint Training ◽  
Ouabain Binding ◽  
Before And After

This study investigated the effects of sprint training on muscle Na(+)-K(+)-adenosinetriphosphatase (ATPase) concentration, plasma [K+] regulation, muscle performance, and fatigue during severe intermittent exercise. Six untrained male subjects underwent intensive cycle-sprint training for 7 wk. Muscle biopsies were taken at rest from the vastus lateralis muscle before and after 7 wk of training and were assayed for Na(+)-K(+)-ATPase concentration using vanadate-facilitated [3H]ouabain binding to intact samples. Before and after the training period, subjects performed four maximal 30-s exercise bouts (EB) on a cycle ergometer, each separated by a 4-min recovery. Arterialized venous blood samples were drawn immediately before and after each sprint bout and were analyzed for plasma [K+]. The work output was significantly elevated (11%) across all four EBs after training. The muscle [3H]ouabain binding site concentration was significantly increased (16%) from 333 +/- 19 to 387 +/- 15 (SE) pmol/g wet wt after training but was unchanged in muscle obtained from three control subjects. Plasma [K+] rose by 1–2 mmol/l with each EB and declined rapidly by the end of each recovery period. The increases in plasma [K+] resulting from each EB were significantly lower (19%) after training. The ratios of rise in plasma [K+] relative to work output during each EB were also significantly lower (27%) after training. The increased muscle [3H]ouabain binding site concentration and the reduced ratio of rise in [K+] relative to work output with exercise are both consistent with improved plasma and skeletal muscle K+ regulation after sprint training.

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