Repeatability of exercise-induced changes in mRNA expression and technical considerations for qPCR analysis in human skeletal muscle

Contracting skeletal muscle expresses large amounts of IL-6. Because 1) IL-6 mRNA expression in contracting skeletal muscle is enhanced by low muscle glycogen content, and 2) IL-6 increases lipolysis and oxidation of fatty acids, we hypothesized that regular exercise training, associated with increased levels of resting muscle glycogen and enhanced capacity to oxidize fatty acids, would lead to a less-pronounced increase of skeletal muscle IL-6 mRNA in response to acute exercise. Thus, before and after 10 wk of knee extensor endurance training, skeletal muscle IL-6 mRNA expression was determined in young healthy men ( n = 7) in response to 3 h of dynamic knee extensor exercise, using the same relative workload. Maximal power output, time to exhaustion during submaximal exercise, resting muscle glycogen content, and citrate synthase and 3-hydroxyacyl-CoA dehydrogenase enzyme activity were all significantly enhanced by training. IL-6 mRNA expression in resting skeletal muscle did not change in response to training. However, although absolute workload during acute exercise was 44% higher ( P < 0.05) after the training period, skeletal muscle IL-6 mRNA content increased 76-fold ( P < 0.05) in response to exercise before the training period, but only 8-fold ( P < 0.05, relative to rest and pretraining) in response to exercise after training. Furthermore, the exercise-induced increase of plasma IL-6 ( P < 0.05, pre- and posttraining) was not higher after training despite higher absolute work intensity. In conclusion, the magnitude of the exercise-induced IL-6 mRNA expression in contracting human skeletal muscle was markedly reduced by 10 wk of training.

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Exercise-induced expression of angiogenesis-related transcription and growth factors in human skeletal muscle

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.1999.276.2.h679 ◽

1999 ◽

Vol 276 (2) ◽

pp. H679-H685 ◽

Cited By ~ 104

Author(s):

Thomas Gustafsson ◽

Adrian Puntschart ◽

Lennart Kaijser ◽

Eva Jansson ◽

Carl Johan Sundberg

Keyword(s):

Skeletal Muscle ◽

Growth Factor ◽

Mrna Expression ◽

Human Skeletal Muscle ◽

Hypoxia Inducible Factor ◽

Lactate Concentration ◽

Knee Extension ◽

Vegf Mrna ◽

Exercise Induced ◽

Vegf Mrna Expression

mRNA expression of vascular endothelial growth factor (VEGF), fibroblast growth factor-2 (FGF-2), and hypoxia-inducible factor (HIF) subunits HIF-1α and HIF-1β in human skeletal muscle was studied during endurance exercise at different degrees of oxygen delivery. Muscle biopsies were taken before and after 45 min of one-legged knee-extension exercise performed under conditions of nonrestricted or restricted blood flow (∼15–20% lower) at the same absolute workload. Exercise increased VEGF mRNA expression by 178% and HIF-1β by 340%, but not HIF-1α and FGF-2. No significant differences between the restricted and nonrestricted groups were observed. The exercise-induced increase in VEGF mRNA was correlated to the exercise changes in HIF-1α and HIF-1β mRNA. The changes in VEGF, HIF-1α, and HIF-1β mRNAs were correlated to the exercise-induced increase in femoral venous plasma lactate concentration. It is concluded that 1) VEGF but not FGF-2 gene expression is upregulated in human skeletal muscle by a single bout of dynamic exercise and that there is a graded response in VEGF mRNA expression related to the metabolic stress and 2) the increase in VEGF mRNA expression correlates to the changes in both HIF-1α and HIF-1β mRNA.

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Nitric oxide production is a proximal signaling event controlling exercise‐induced mRNA expression in human skeletal muscle

The FASEB Journal ◽

10.1096/fj.06-7477com ◽

2007 ◽

Vol 21 (11) ◽

pp. 2683-2694 ◽

Cited By ~ 55

Author(s):

Adam Steensberg ◽

Charlotte Keller ◽

Thore Hillig ◽

Christian Frøsig ◽

Jørgen F. P. Wojtaszewski ◽

...

Keyword(s):

Nitric Oxide ◽

Skeletal Muscle ◽

Mrna Expression ◽

Human Skeletal Muscle ◽

Nitric Oxide Production ◽

Oxide Production ◽

Exercise Induced ◽

Proximal Signaling

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A Modular Mathematical Model of Exercise-Induced Changes in Metabolism, Signaling, and Gene Expression in Human Skeletal Muscle

International Journal of Molecular Sciences ◽

10.3390/ijms221910353 ◽

2021 ◽

Vol 22 (19) ◽

pp. 10353

Author(s):

Ilya R. Akberdin ◽

Ilya N. Kiselev ◽

Sergey S. Pintus ◽

Ruslan N. Sharipov ◽

Alexander Yu Vertyshev ◽

...

Keyword(s):

Gene Expression ◽

Skeletal Muscle ◽

Signaling Pathways ◽

Human Skeletal Muscle ◽

Genetic Regulation ◽

Muscle Fibres ◽

Modular Modeling ◽

Systematic Understanding ◽

Exercise Induced ◽

Induced Changes

Skeletal muscle is the principal contributor to exercise-induced changes in human metabolism. Strikingly, although it has been demonstrated that a lot of metabolites accumulating in blood and human skeletal muscle during an exercise activate different signaling pathways and induce the expression of many genes in working muscle fibres, the systematic understanding of signaling–metabolic pathway interrelations with downstream genetic regulation in the skeletal muscle is still elusive. Herein, a physiologically based computational model of skeletal muscle comprising energy metabolism, Ca2+, and AMPK (AMP-dependent protein kinase) signaling pathways and the expression regulation of genes with early and delayed responses was developed based on a modular modeling approach and included 171 differential equations and more than 640 parameters. The integrated modular model validated on diverse including original experimental data and different exercise modes provides a comprehensive in silico platform in order to decipher and track cause–effect relationships between metabolic, signaling, and gene expression levels in skeletal muscle.

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Regular endurance training reduces the exercise induced HIF-1α and HIF-2α mRNA expression in human skeletal muscle in normoxic conditions

European Journal of Applied Physiology ◽

10.1007/s00421-005-0085-5 ◽

2005 ◽

Vol 96 (4) ◽

pp. 363-369 ◽

Cited By ~ 66

Author(s):

Carsten Lundby ◽

Max Gassmann ◽

Henriette Pilegaard

Keyword(s):

Skeletal Muscle ◽

Mrna Expression ◽

Endurance Training ◽

Human Skeletal Muscle ◽

Exercise Induced

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Contraction-induced increases in Na+-K+-ATPase mRNA levels in human skeletal muscle are not amplified by activation of additional muscle mass

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.00771.2004 ◽

2005 ◽

Vol 289 (1) ◽

pp. R84-R91 ◽

Cited By ~ 25

Author(s):

Nikolai Nordsborg ◽

Martin Thomassen ◽

Carsten Lundby ◽

Henriette Pilegaard ◽

Jens Bangsbo

Keyword(s):

Skeletal Muscle ◽

Mrna Expression ◽

Muscle Mass ◽

Human Skeletal Muscle ◽

Mrna Level ◽

Venous Blood ◽

Knee Extension ◽

Mrna Levels ◽

Atpase Subunit ◽

Exercise Induced

The present study tested the hypothesis that exercise with a large compared with a small active muscle mass results in a higher contraction-induced increase in Na+-K+-ATPase mRNA expression due to greater hormonal responses. Furthermore, the relative abundance of Na+-K+-ATPase subunit α1, α2, α3, α4, β1, β2, and β3 mRNA in human skeletal muscle was investigated. On two occasions, eight subjects performed one-legged knee extension exercise (L) or combined one-legged knee extension and bilateral arm cranking (AL) for 5.00, 4.25, 3.50, 2.75, and 2.00 min separated by 3 min of rest. Leg exercise power output was the same in AL and L, but heart rate at the end of each exercise interval was higher in AL compared with L. One minute after exercise, arm venous blood lactate was higher in AL than in L. A higher level of blood epinephrine and norepinephrine was evident 3 min after exercise in AL compared with L. Nevertheless, none of the exercise-induced increases in α1, α2, β1, and β3 mRNA expression levels were higher in AL compared with L. The most abundant Na+-K+-ATPase subunit at the mRNA level was β1, which was expressed 3.4 times than α2. Expression of α1, β2, and β3 was less than 5% of the α2 expression, and no reliable detection of α3 and α4 was possible. In conclusion, activation of additional muscle mass does not result in a higher exercise-induced increase in Na+-K+-ATPase subunit-specific mRNA.

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Resistance exercise-induced changes of inflammatory gene expression within human skeletal muscle

European Journal of Applied Physiology ◽

10.1007/s00421-009-1145-z ◽

2009 ◽

Vol 107 (4) ◽

pp. 463-471 ◽

Cited By ~ 64

Author(s):

Thomas W. Buford ◽

Matthew B. Cooke ◽

Darryn S. Willoughby

Keyword(s):

Gene Expression ◽

Skeletal Muscle ◽

Resistance Exercise ◽

Human Skeletal Muscle ◽

Inflammatory Gene Expression ◽

Inflammatory Gene ◽

Exercise Induced ◽

Induced Changes

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Physical exercise increases autophagic signaling through ULK1 in human skeletal muscle

Journal of Applied Physiology ◽

10.1152/japplphysiol.01116.2014 ◽

2015 ◽

Vol 118 (8) ◽

pp. 971-979 ◽

Cited By ~ 58

Author(s):

Andreas Buch Møller ◽

Mikkel Holm Vendelbo ◽

Britt Christensen ◽

Berthil Forrest Clasen ◽

Ann Mosegaard Bak ◽

...

Keyword(s):

Skeletal Muscle ◽

Physical Exercise ◽

Light Chain ◽

Human Skeletal Muscle ◽

Transgenic Animal ◽

Dependent Manner ◽

Healthy Humans ◽

Transgenic Animal Models ◽

Exercise Induced

Data from transgenic animal models suggest that exercise-induced autophagy is critical for adaptation to physical training, and that Unc-51 like kinase-1 (ULK1) serves as an important regulator of autophagy. Phosphorylation of ULK1 at Ser555 stimulates autophagy, whereas phosphorylation at Ser757 is inhibitory. To determine whether exercise regulates ULK1 phosphorylation in humans in vivo in a nutrient-dependent manner, we examined skeletal muscle biopsies from healthy humans after 1-h cycling exercise at 50% maximal O2 uptake on two occasions: 1) during a 36-h fast, and 2) during continuous glucose infusion at 0.2 kg/h. Physical exercise increased ULK1 phosphorylation at Ser555 and decreased lipidation of light chain 3B. ULK1 phosphorylation at Ser555 correlated positively with AMP-activated protein kinase-α Thr172 phosphorylation and negatively with light chain 3B lipidation. ULK1 phosphorylation at Ser757 was not affected by exercise. Fasting increased ULK1 and p62 protein expression, but did not affect exercise-induced ULK1 phosphorylation. These data demonstrate that autophagy signaling is activated in human skeletal muscle after 60 min of exercise, independently of nutritional status, and suggest that initiation of autophagy constitutes an important physiological response to exercise in humans.

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Skeletal muscle adaptations to exercise are not influenced by metformin treatment in humans: secondary analyses of two randomised, clinical trials.

Applied Physiology Nutrition and Metabolism ◽

10.1139/apnm-2021-0194 ◽

2021 ◽

Author(s):

Nanna Skytt Pilmark ◽

Laura Oberholzer ◽

Jens Frey Halling ◽

Jonas M. Kristensen ◽

Christina Pedersen Bønding ◽

...

Keyword(s):

Oxidative Stress ◽

Skeletal Muscle ◽

Exercise Training ◽

Human Skeletal Muscle ◽

Acute Exercise ◽

Metformin Treatment ◽

Ampk Activation ◽

Double Blind ◽

Parallel Group ◽

Exercise Induced

Metformin and exercise both improve glycemic control, but in vitro studies have indicated that an interaction between metformin and exercise occurs in skeletal muscle, suggesting a blunting effect of metformin on exercise training adaptations. Two studies (a double-blind, parallel-group, randomized clinical trial conducted in 29 glucose-intolerant individuals and a double-blind, cross-over trial conducted in 15 healthy lean males) were included in this paper. In both studies, the effect of acute exercise +/- metformin treatment on different skeletal muscle variables, previously suggested to be involved in a pharmaco-physiological interaction between metformin and exercise, was assessed. Furthermore, in the parallel-group trial, the effect of 12 weeks of exercise training was assessed. Skeletal muscle biopsies were obtained before and after acute exercise and 12 weeks of exercise training, and mitochondrial respiration, oxidative stress and AMPK activation was determined. Metformin did not significantly affect the effects of acute exercise or exercise training on mitochondrial respiration, oxidative stress or AMPK activation, indicating that the response to acute exercise and exercise training adaptations in skeletal muscle is not affected by metformin treatment. Further studies are needed to investigate whether an interaction between metformin and exercise is present in other tissues, e.g. the gut. Trial registration: ClinicalTrials.gov (NCT03316690 and NCT02951260). Novelty bullets • Metformin does not affect exercise-induced alterations in mitochondrial respiratory capacity in human skeletal muscle • Metformin does not affect exercise-induced alterations in systemic levels of oxidative stress nor emission of reactive oxygen species from human skeletal muscle • Metformin does not affect exercise-induced AMPK activation in human skeletal muscle

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Hormone therapy attenuates exercise-induced skeletal muscle damage in postmenopausal women

Journal of Applied Physiology ◽

10.1152/japplphysiol.00404.2009 ◽

2009 ◽

Vol 107 (3) ◽

pp. 853-858 ◽

Cited By ~ 54

Author(s):

Christina M. Dieli-Conwright ◽

Tanya M. Spektor ◽

Judd C. Rice ◽

E. Todd Schroeder

Keyword(s):

Skeletal Muscle ◽

Hormone Therapy ◽

Mrna Expression ◽

Postmenopausal Women ◽

Muscle Damage ◽

Exercise Bout ◽

Control Group ◽

Skeletal Muscle Damage ◽

Tnf Α ◽

Exercise Induced

Hormone therapy (HT) is a potential treatment to relieve symptoms of menopause and prevent the onset of disease such as osteoporosis in postmenopausal women. We evaluated changes in markers of exercise-induced skeletal muscle damage and inflammation [serum creatine kinase (CK), serum lactate dehydrogenase (LDH), and skeletal muscle mRNA expression of IL-6, IL-8, IL-15, and TNF-α] in postmenopausal women after a high-intensity resistance exercise bout. Fourteen postmenopausal women were divided into two groups: women not using HT (control; n = 6, 59 ± 4 yr, 63 ± 17 kg) and women using traditional HT (HT; n = 8, 59 ± 4 yr, 89 ± 24 kg). Both groups performed 10 sets of 10 maximal eccentric repetitions of single-leg extension on the Cybex dynamometer at 60°/s with 20-s rest periods between sets. Muscle biopsies of the vastus lateralis were obtained from the exercised leg at baseline and 4 h after the exercise bout. Gene expression was determined by RT-PCR for IL-6, IL-8, IL-15, and TNF-α. Blood draws were performed at baseline and 3 days after exercise to measure CK and LDH. Independent t-tests were performed to test group differences (control vs. HT). A probability level of P ≤ 0.05 was used to determine statistical significance. We observed significantly greater changes in mRNA expression of IL-6, IL-8, IL-15, and TNF-α ( P ≤ 0.01) in the control group compared with the HT group after the exercise bout. CK and LDH levels were significantly greater after exercise ( P ≤ 0.01) in the control group. Postmenopausal women not using HT experienced greater muscle damage after maximal eccentric exercise, indicating a possible protective effect of HT against exercise-induced skeletal muscle damage.

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