scholarly journals The role of Nrf2 in skeletal muscle contractile and mitochondrial function

2016 ◽  
Vol 121 (3) ◽  
pp. 730-740 ◽  
Author(s):  
Matthew J. Crilly ◽  
Liam D. Tryon ◽  
Avigail T. Erlich ◽  
David A. Hood
Keyword(s):  
Skeletal Muscle ◽  
Exercise Training ◽  
Mitochondrial Function ◽  
Fold Increase ◽  
Muscle Performance ◽  
Related Factor ◽  
Cellular Protection ◽  
Nrf2 Activation ◽  
Normal Increase

Nuclear factor erythroid 2-related factor 2 (Nrf2) is a transcription factor that confers cellular protection by upregulating antioxidant enzymes in response to oxidative stress. However, Nrf2 function within skeletal muscle remains to be further elucidated. We examined the role of Nrf2 in determining muscle phenotype using young (3 mo) and older (12 mo) Nrf2 wild-type (WT) and knockout (KO) mice. Basally, the absence of Nrf2 did not impact mitochondrial content. In intermyofibrillar mitochondria, lack of Nrf2 resulted in a 40% reduction in state 4 respiration, which coincided with a 68% increase in reactive oxygen species (ROS) emission. Nrf2 abrogation impaired in situ muscle performance, characterized by a 48% greater rate of fatigue and a 35% decrease in force within the first 5 min of stimulation. Acute treadmill exercise resulted in a 1.5-fold increase in Nrf2 activation via enhanced DNA binding in WT animals. In response to training, cytochrome- c oxidase activity increased by 20% in the WT animals; however, this response was attenuated in KO mice. Nrf2 protein was reduced 30% by training. Despite this, exercise training normalized respiration, ROS production, and muscle performance in KO mice. Our results suggest that Nrf2 transcriptional activity is increased by exercise and that Nrf2 is required for the maintenance of basal mitochondrial function as well as for the normal increase in specific mitochondrial proteins in response to training. Nonetheless, the decrements in mitochondrial function in Nrf2 KO muscle can be rescued by exercise training, suggesting that this restorative function operates via a pathway independent of Nrf2.

scholarly journals The vitamin D receptor regulates mitochondrial function in C2C12 myoblasts

2020 ◽  
Vol 318 (3) ◽  
pp. C536-C541 ◽  
Author(s):  
Stephen P. Ashcroft ◽  
Joseph J. Bass ◽  
Abid A. Kazi ◽  
Philip J. Atherton ◽  
Andrew Philp
Keyword(s):  
Skeletal Muscle ◽  
Vitamin D ◽  
Protein Content ◽  
Vitamin D Receptor ◽  
Mitochondrial Function ◽  
Mitochondrial Respiration ◽  
Oxidative Capacity ◽  
C2c12 Myoblasts

Vitamin D deficiency has been linked to a reduction in skeletal muscle function and oxidative capacity; however, the mechanistic bases of these impairments are poorly understood. The biological actions of vitamin D are carried out via the binding of 1α,25-dihydroxyvitamin D3 (1α,25(OH)2D3) to the vitamin D receptor (VDR). Recent evidence has linked 1α,25(OH)2D3 to the regulation of skeletal muscle mitochondrial function in vitro; however, little is known with regard to the role of the VDR in this process. To examine the regulatory role of the VDR in skeletal muscle mitochondrial function, we used lentivirus-mediated shRNA silencing of the VDR in C2C12 myoblasts (VDR-KD) and examined mitochondrial respiration and protein content compared with an shRNA scrambled control. VDR protein content was reduced by ~95% in myoblasts and myotubes ( P < 0.001). VDR-KD myoblasts displayed a 30%, 30%, and 36% reduction in basal, coupled, and maximal respiration, respectively ( P < 0.05). This phenotype was maintained in VDR-KD myotubes, displaying a 34%, 33%, and 48% reduction in basal, coupled, and maximal respiration ( P < 0.05). Furthermore, ATP production derived from oxidative phosphorylation (ATPOx) was reduced by 20%, suggesting intrinsic impairments within the mitochondria following VDR-KD. However, despite the observed functional decrements, mitochondrial protein content, as well as markers of mitochondrial fission were unchanged. In summary, we highlight a direct role for the VDR in regulating skeletal muscle mitochondrial respiration in vitro, providing a potential mechanism as to how vitamin D deficiency might impact upon skeletal muscle oxidative capacity.

scholarly journals Resistance Exercise Training Alters Mitochondrial Function in Human Skeletal Muscle

2015 ◽  
Vol 47 (9) ◽  
pp. 1922-1931 ◽  
Author(s):  
CRAIG PORTER ◽  
PAUL T. REIDY ◽  
NISHA BHATTARAI ◽  
LABROS S. SIDOSSIS ◽  
BLAKE B. RASMUSSEN
Keyword(s):  
Skeletal Muscle ◽  
Exercise Training ◽  
Resistance Exercise ◽  
Mitochondrial Function ◽  
Human Skeletal Muscle ◽  
Resistance Exercise Training

Exercise training leads to a reduction of elevated myostatin levels in patients with chronic heart failure

2011 ◽  
Vol 19 (3) ◽  
pp. 404-411 ◽  
Author(s):  
Karsten Lenk ◽  
Sandra Erbs ◽  
Robert Höllriegel ◽  
Ephraim Beck ◽  
Axel Linke ◽  
...  
Keyword(s):  
Heart Failure ◽  
Skeletal Muscle ◽  
Chronic Heart Failure ◽  
Exercise Training ◽  
Serum Concentration ◽  
Late Stage ◽  
Healthy Subjects ◽  
Fold Increase ◽  
Control Group ◽  
Cardiac Cachexia

Background: In chronic heart failure (CHF), cardiac cachexia is often associated with the terminal stage of this disease. In animal studies it has been demonstrated that myostatin, a key regulator of skeletal muscle mass, is elevated in advanced stages of this syndrome. Design: The aim of the present study was to investigate the expression of myostatin in patients with late stage CHF (NYHA IIIb) in comparison to healthy subjects. Furthermore the effects of physical exercise on myostatin were analyzed. Methods: Twenty-four patients were either randomized to a sedentary control group (CHF-S) or exercise training (CHF-E). At baseline and after 12 weeks mRNA and myostatin protein in the peripheral skeletal muscle as well as myostatin serum concentration were measured. Furthermore 12 age-matched healthy men were compared to all patients at baseline (HC). Results: CHF patients showed a two-fold increase of myostatin mRNA ( p = 0.05) and a 1.7-fold ( p = 0.01) augmentation of protein content in skeletal muscle compared to healthy subjects. In late-stage CHF, exercise training led to a 36% reduction of the mRNA and a 23% decrease of the myostatin protein compared to baseline. The serum concentration of myostatin revealed no significant alteration between the groups. Conclusion: In the skeletal muscle, myostatin increases significantly in the course of CHF. The observed effects of a significant reduction of myostatin in skeletal muscle after 12 weeks of exercise training demonstrate the reversibility of molecular changes that might be able to halt the devastating process of muscle wasting in chronic heart failure.

scholarly journals Oxidative stress and mitochondrial function in skeletal muscle: Effects of aging and exercise training

AGE ◽  
1998 ◽  
Vol 21 (3) ◽  
pp. 109-117 ◽  
Author(s):  
Raj Chandwaney ◽  
Steve Leichtweis ◽  
Christiaan Leeuwenburgh ◽  
Li Li Ji
Keyword(s):  
Oxidative Stress ◽  
Skeletal Muscle ◽  
Exercise Training ◽  
Mitochondrial Function ◽  
Effects Of Aging

scholarly journals The Vitamin D Receptor (VDR) Regulates Mitochondrial Function in C2C12 Myoblasts

2019 ◽  
Author(s):  
Stephen P. Ashcroft ◽  
Joseph J. Bass ◽  
Abid A. Kazi ◽  
Philip J. Atherton ◽  
Andrew Philp
Keyword(s):  
Skeletal Muscle ◽  
Vitamin D ◽  
Protein Content ◽  
Vitamin D Receptor ◽  
Mitochondrial Function ◽  
Mitochondrial Respiration ◽  
Oxidative Capacity ◽  
C2c12 Myoblasts

ABSTRACTVitamin D deficiency has been linked to a reduction in skeletal muscle function and oxidative capacity, however, the mechanistic basis of these impairments are poorly understood. The biological actions of vitamin D are carried out via the binding of 1α,25-dihydroxyvitamin D3 (1α,25(OH)2D3) to the vitamin D receptor (VDR). Recent evidence has linked 1α,25(OH)2D3 to the regulation of skeletal muscle mitochondrial function in vitro, however, little is known with regard to the role of the VDR in this process. To examine the regulatory role of the VDR in skeletal muscle mitochondrial function, we utilised lentiviral mediated shRNA silencing of the VDR in C2C12 myoblasts (VDR-KD) and examined mitochondrial respiration and protein content compared to shRNA scrambled control. VDR protein content was reduced by ~95% in myoblasts and myotubes (P < 0.001). VDR-KD myoblasts displayed a 30%, 30% and 36% reduction in basal, coupled and maximal respiration respectively (P < 0.05). This phenotype was maintained in VDR-KD myotubes, displaying a 34%, 33% and 48% reduction in basal, coupled and maximal respiration (P < 0.05). Furthermore, ATP production derived from oxidative phosphorylation (ATPox) was reduced by 20% suggesting intrinsic impairments within the mitochondria following VDR-KD. However, despite the observed functional decrements, mitochondrial protein content as well as markers of fusion and fission were unchanged. In summary, we highlight a direct role for the VDR in regulating skeletal muscle mitochondrial respiration in vitro, providing a potential mechanism as to how vitamin D deficiency might impact upon skeletal muscle oxidative capacity.

scholarly journals Mitochondrial Adaptations in Aged Skeletal Muscle: Effect of Exercise Training

2017 ◽  
pp. 1-14 ◽  
Author(s):  
M. M. ZIAALDINI ◽  
S. R. A. HOSSEINI ◽  
M. FATHI
Keyword(s):  
Skeletal Muscle ◽  
Exercise Training ◽  
Mitochondrial Function ◽  
The Elderly ◽  
Elderly Subjects ◽  
Cellular Mechanisms ◽  
Healthy Elderly ◽  
Mitochondrial Functions ◽  
Healthy Elderly Subjects ◽  
Mitochondrial Adaptations

The aging process is associated with a decline in mitochondrial functions. Mitochondria dysfunction is involved in initiation and progression of many health problems including neuromuscular, metabolic and cardiovascular diseases. It is well known that endurance exercise improves mitochondrial function, especially in the elderly. However, recent studies have demonstrated that resistance training lead also to substantial increases in mitochondrial function in skeletal muscle. A comprehensive understanding of the cellular mechanisms involved in the skeletal muscle mitochondrial adaptations to exercise training in healthy elderly subjects, can help practitioners to design and prescribe more effective exercise trainings.

Abstract 17514: Hydrogen Sulfide Levels and NRF2 Activity are Attenuated in the Setting of Critical Limb Ischemia (CLI)

Circulation ◽  
2014 ◽  
Vol 130 (suppl_2) ◽  
Author(s):  
Kazi N Islam ◽  
David J Polhemus ◽  
Erminia Donnarumma ◽  
Hiroyuki Otsuka ◽  
Shashi Bhushan ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Skeletal Muscle ◽  
Hydrogen Sulfide ◽  
Limb Ischemia ◽  
Antioxidant Response ◽  
Protein Carbonyl ◽  
Related Factor ◽  
Mobility Shift ◽  
Protein Levels ◽  
Nrf2 Activation

Background: Cystathionine γ-lyase (CSE), cystathionine β-synthase (CBS), and 3-mercaptopyruvate sulfurtransferase (3-MST) are enzymatic sources of hydrogen sulfide (H2S). Functions of H2S are mediated by several targets including ion channels and signaling proteins. Nuclear factor-erythriod 2-related factor 2 (NRF2) is responsible for the expression of antioxidant response element (ARE)-regulated genes and is known to be upregulated by H2S. We examined the levels of H2S producing enzymes, H2S, and NRF2 activation status in skeletal muscle obtained from CLI patients. Methods: Gastrocnemius tissues were attained post amputation from human CLI and aged-matched control patients. Tissue H2S levels were measured using gas chromatography methods coupled with sulfur chemiluminescence. RT-qPCR, immunoblot, and electrophoretic mobility shift assay (EMSA) were used to analyze respective gene expression, protein levels, and DNA binding activity, respectively. Results: We found mRNA and protein levels of CSE, CBS, and 3-MST were significantly decreased in skeletal muscle of CLI (~2 fold, p < 0.05) patients as compared to control. H2S and sulfane sulfur levels were significantly decreased in skeletal muscle of CLI patients. We also observed significant reductions in NRF2 activation (2 fold, p < 0.05) as well as antioxidant proteins, such as CuZn-superoxide dismutase (2 fold, p < 0.05), catalase (2 fold, p < 0.05), and glutathione peroxidase (2 fold, p < 0.05) in skeletal muscle of CLI patients. Biomarkers of oxidative stress, such as malondialdehyde and protein carbonyl formation were significantly increased (2 fold, p < 0.05) in skeletal muscle of CLI patients as compared to age-matched controls. Conclusions: The data demonstrate that H2S bioavailability and NRF2 activation are both attenuated in CLI tissues concomitant with significantly increased oxidative stress. Reductions in the activity of H2S producing enzymes may contribute to the pathogenesis of CLI.

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