scholarly journals Regulation of Skeletal Muscle DRP-1 and FIS-1 Protein Expression by IL-6 Signaling

2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Dennis K. Fix ◽  
Brandon N. VanderVeen ◽  
Brittany R. Counts ◽  
James A. Carson
Keyword(s):  
Skeletal Muscle ◽  
Intracellular Signaling ◽  
Transmembrane Protein ◽  
Mitochondrial Fission ◽  
Tibialis Anterior Muscle ◽  
C2c12 Myotubes ◽  
Extracellular Signal ◽  
Control Plasmid ◽  
Cultured Myotubes ◽  
Transcription 3

IL-6 signals through the ubiquitously expressed glycoprotein 130 (gp130) transmembrane protein to activate intracellular signaling that includes signal transducer and activator of transcription 3 (STAT3) and extracellular signal-regulated kinase 1/2 (ERK1/2). Dynamin-1-like protein (DRP-1) and mitochondrial fission 1 protein (FIS-1) are key proteins in the process of mitochondrial fission and have emerged as IL-6-sensitive targets. The purpose of this study was to examine the regulation of DRP-1 and FIS-1 expression by IL-6 and gp130 signaling in myotubes and skeletal muscle. Fully differentiated C2C12 myotubes were treated with 100 ng of IL-6 for 24 hours in the presence of gp130siRNA, C188-9 (STAT3 inhibitor), or PD98059 (ERK1/2 inhibitor). Male C57BL/6 (B6) and muscle-specific gp130 knockout mice (KO) had IL-6 systemically overexpressed for 2 weeks by transient transfection with 50 ng of an IL-6-expressing or control plasmid in the quadriceps muscles, and the tibialis anterior muscle was analyzed to determine systemic effects of IL-6. IL-6 induced DRP-1 and FIS-1 expression in myotubes 124% and 82% (p=.001) and in skeletal muscle 97% and 187% (p=.001). Myotube gp130 knockdown suppressed the IL-6 induction of DRP-1 68% (p=.002) and FIS-1 65% (p=.001). Muscle KO suppressed the IL-6 induction of DRP-1 220% (p=.001) and FIS-1 121% (p=.001). ERK1/2 inhibition suppressed the IL-6 induction of DRP-1 59% (p=.0003) and FIS-1 102% (p=.0001) in myotubes, while there was no effect of STAT3 inhibition. We report that chronically elevated IL-6 can directly induce DRP-1 and FIS-1 expression through gp130 signaling in cultured myotubes and skeletal muscle. Furthermore, ERK 1/2 signaling is necessary for the IL-6 induction of DRP-1 and FIS-1 expression in myotubes.

scholarly journals UBE2E1 Is Preferentially Expressed in the Cytoplasm of Slow-Twitch Fibers and Protects Skeletal Muscles from Exacerbated Atrophy upon Dexamethasone Treatment

Cells ◽  
2018 ◽  
Vol 7 (11) ◽  
pp. 214 ◽  
Author(s):  
Cécile Polge ◽  
Julien Aniort ◽  
Andrea Armani ◽  
Agnès Claustre ◽  
Cécile Coudy-Gandilhon ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Muscle Mass ◽  
Muscle Atrophy ◽  
Tibialis Anterior Muscle ◽  
Ubiquitin Proteasome System ◽  
Skeletal Muscle Atrophy ◽  
C2c12 Myotubes ◽  
Type I ◽  
Dexamethasone Treatment ◽  
Sarcomeric Protein

Skeletal muscle mass is reduced during many diseases or physiological situations (disuse, aging), which results in decreased strength and increased mortality. Muscle mass is mainly controlled by the ubiquitin-proteasome system (UPS), involving hundreds of ubiquitinating enzymes (E2s and E3s) that target their dedicated substrates for subsequent degradation. We recently demonstrated that MuRF1, an E3 ubiquitin ligase known to bind to sarcomeric proteins (telethonin, α-actin, myosins) during catabolic situations, interacts with 5 different E2 enzymes and that these E2-MuRF1 couples are able to target telethonin, a small sarcomeric protein, for degradation. Amongst the E2s interacting with MuRF1, E2E1 was peculiar as the presence of the substrate was necessary for optimal MuRF1-E2E1 interaction. In this work, we focused on the putative role of E2E1 during skeletal muscle atrophy. We found that E2E1 expression was restricted to type I and type IIA muscle fibers and was not detectable in type IIB fibers. This strongly suggests that E2E1 targets are fiber-specific and may be strongly linked to the contractile and metabolic properties of the skeletal muscle. However, E2E1 knockdown was not sufficient for preserving the protein content in C2C12 myotubes subjected to a catabolic state (dexamethasone treatment), suggesting that E2E1 is not involved in the development of muscle atrophy. By contrast, E2E1 knockdown aggravated the atrophying process in both catabolic C2C12 myotubes and the Tibialis anterior muscle of mice, suggesting that E2E1 has a protective effect on muscle mass.

scholarly journals Citrus hassaku Extract Powder Increases Mitochondrial Content and Oxidative Muscle Fibers by Upregulation of PGC-1α in Skeletal Muscle

Nutrients ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 497
Author(s):  
Shiori Akashi ◽  
Akihito Morita ◽  
Yusuke Mochizuki ◽  
Fuka Shibuya ◽  
Yasutomi Kamei ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Skeletal Muscles ◽  
Control Diet ◽  
C2c12 Myotubes ◽  
Peroxisome Proliferator ◽  
Mitochondrial Content ◽  
Peroxisome Proliferator Activated Receptor ◽  
Cultured Myotubes ◽  
Citrus Hassaku ◽  
Amp Activated Protein Kinase

Peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α) is expressed in skeletal muscles and regulates systemic metabolism. Thus, nutraceuticals targeting skeletal muscle PGC-1α have attracted attention to modulate systemic metabolism. As auraptene contained in citrus fruits promotes lipid metabolism and improves mitochondrial respiration, it could increase mitochondrial function through PGC-1α. Therefore, we hypothesized that PGC-1α is activated by auraptene and investigated its effect using Citrus hassaku extract powder (CHEP) containing >80% of auraptene. C2C12 myotubes were incubated with vehicle or CHEP for 24 h; C57BL/6J mice were fed a control diet or a 0.25% (w/w) CHEP-containing diet for 5 weeks. PGC-1α protein level and mitochondrial content increased following CHEP treatment in cultured myotubes and skeletal muscles. In addition, the number of oxidative fibers increased in CHEP-fed mice. These findings suggest that CHEP-mediated PGC-1α upregulation induced mitochondrial biogenesis and fiber transformation to oxidative fibers. Furthermore, as CHEP increased the expression of the protein sirtuin 3 and of phosphorylated AMP-activated protein kinase (AMPK) and the transcriptional activity of PGC-1α, these molecules might be involved in CHEP-induced effects in skeletal muscles. Collectively, our findings indicate that CHEP mediates PGC-1α expression in skeletal muscles and may serve as a dietary supplement to prevent metabolic disorders.

Oleamide rescues tibialis anterior muscle atrophy of mice housed in small cages

2020 ◽  
pp. 1-11
Author(s):  
Yasuyuki Kobayashi ◽  
Natsumi Watanabe ◽  
Tomoya Kitakaze ◽  
Keiichiro Sugimoto ◽  
Takeshi Izawa ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Plasma Concentration ◽  
Muscle Atrophy ◽  
Tibialis Anterior ◽  
Metabolic Diseases ◽  
Tibialis Anterior Muscle ◽  
Skeletal Muscle Atrophy ◽  
C2c12 Myotubes ◽  
Sequestosome 1 ◽  
Increased Risk

Abstract Skeletal muscle atrophy causes decreased physical activity and increased risk of metabolic diseases. We investigated the effects of oleamide (cis-9,10-octadecanamide) treatment on skeletal muscle health. The plasma concentration of endogenous oleamide was approximately 30 nm in male ddY mice under normal physiological conditions. When the stable isotope-labelled oleamide was orally administered to male ddY mice (50 mg/kg), the plasma concentration of exogenous oleamide reached approximately 170 nm after 1 h. Male ddY mice were housed in small cages (one-sixth of normal size) to enforce sedentary behaviour and orally administered oleamide (50 mg/kg per d) for 4 weeks. Housing in small cages decreased tibialis anterior (TA) muscle mass and the cross-sectional area of the myofibres in TA muscle. Dietary oleamide alleviated the decreases in TA muscle and resulted in plasma oleamide concentration of approximately 120 nm in mice housed in small cages. Housing in small cages had no influence on the phosphorylation levels of Akt serine/threonine kinase (Akt), mechanistic target of rapamycin (mTOR) and ribosomal protein S6 kinase (p70S6K) in TA muscle; nevertheless, oleamide increased the phosphorylation levels of the proteins. Housing in small cages increased the expression of microtubule-associated protein 1 light chain 3 (LC3)-II and sequestosome 1 (p62), but not LC3-I, in TA muscle, and oleamide reduced LC3-I, LC3-II and p62 expression levels. In C2C12 myotubes, oleamide increased myotube diameter at ≥100 nm. Furthermore, the mTOR inhibitor, Torin 1, suppressed oleamide-induced increases in myotube diameter and protein synthesis. These results indicate that dietary oleamide rescued TA muscle atrophy in mice housed in small cages, possibly by activating the phosphoinositide 3-kinase/Akt/mTOR signalling pathway and restoring autophagy flux.

scholarly journals Differentiation of Murine C2C12 Myoblasts Strongly Reduces the Effects of Myostatin on Intracellular Signaling

Biomolecules ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 695
Author(s):  
Juulia H. Lautaoja ◽  
Satu Pekkala ◽  
Arja Pasternack ◽  
Mika Laitinen ◽  
Olli Ritvos ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Intracellular Signaling ◽  
Negative Regulator ◽  
C2c12 Cells ◽  
C2c12 Myotubes ◽  
Receptor Ligands ◽  
In Vivo Models ◽  
Altered Expression ◽  
Activin Receptor ◽  
Noncanonical Signaling

Alongside in vivo models, a simpler and more mechanistic approach is required to study the effects of myostatin on skeletal muscle because myostatin is an important negative regulator of muscle size. In this study, myostatin was administered to murine (C2C12) and human (CHQ) myoblasts and myotubes. Canonical and noncanonical signaling downstream to myostatin, related ligands, and their receptor were analyzed. The effects of tumorkines were analyzed after coculture of C2C12 and colon cancer-C26 cells. The effects of myostatin on canonical and noncanonical signaling were strongly reduced in C2C12 cells after differentiation. This may be explained by increased follistatin, an endogenous blocker of myostatin and altered expression of activin receptor ligands. In contrast, CHQ cells were equally responsive to myostatin, and follistatin remained unaltered. Both myostatin administration and the coculture stimulated pathways associated with inflammation, especially in C2C12 cells. In conclusion, the effects of myostatin on intracellular signaling may be cell line- or organism-specific, and C2C12 myotubes seem to be a nonoptimal in vitro model for investigating the effects of myostatin on canonical and noncanonical signaling in skeletal muscle. This may be due to altered expression of activin receptor ligands and their regulators during muscle cell differentiation.

Lack of Smad3 signaling leads to impaired skeletal muscle regeneration

2012 ◽  
Vol 303 (1) ◽  
pp. E90-E102 ◽  
Author(s):  
Xiaojia Ge ◽  
Anuradha Vajjala ◽  
Craig McFarlane ◽  
Walter Wahli ◽  
Mridula Sharma ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Mitochondrial Biogenesis ◽  
Muscle Regeneration ◽  
Intracellular Signaling ◽  
Muscle Injury ◽  
Transforming Growth Factor ◽  
Tibialis Anterior Muscle ◽  
Skeletal Muscle Regeneration ◽  
Muscle Weight

Smad3 is a key intracellular signaling mediator for both transforming growth factor-β and myostatin, two major regulators of skeletal muscle growth. Previous published work has revealed pronounced muscle atrophy together with impaired satellite cell functionality in Smad3-null muscles. In the present study, we have further validated a role for Smad3 signaling in skeletal muscle regeneration. Here, we show that Smad3-null mice had incomplete recovery of muscle weight and myofiber size after muscle injury. Histological/immunohistochemical analysis suggested impaired inflammatory response and reduced number of activated myoblasts during the early stages of muscle regeneration in the tibialis anterior muscle of Smad3-null mice. Nascent myofibers formed after muscle injury were also reduced in number. Moreover, Smad3-null regenerated muscle had decreased oxidative enzyme activity and impaired mitochondrial biogenesis, evident by the downregulation of the gene encoding mitochondrial transcription factor A, a master regulator of mitochondrial biogenesis. Consistent with known Smad3 function, reduced fibrotic tissue formation was also seen in regenerated Smad3-null muscle. In conclusion, Smad3 deficiency leads to impaired muscle regeneration, which underscores an essential role of Smad3 in postnatal myogenesis. Given the negative role of myostatin during muscle regeneration, the increased expression of myostatin observed in Smad3-null muscle may contribute to the regeneration defects.

scholarly journals MENS-associated increase of muscular protein content via modulation of caveolin-3 and TRIM72

2019 ◽  
pp. 265-273 ◽  
Author(s):  
Y. Ohno ◽  
T. Egawa ◽  
S. Yokoyama ◽  
H. Fujiya ◽  
T. Sugiura ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Protein Content ◽  
Sports Medicine ◽  
Muscle Protein ◽  
Control Level ◽  
C2c12 Myotubes ◽  
Phosphorylation Level ◽  
Transient Activation ◽  
Intracellular Signals ◽  
Extracellular Signal

Microcurrent electrical neuromuscular stimulation (MENS) is known as an extracellular stimulus for the regeneration of injured skeletal muscle in sports medicine. However, the effects of MENS-associated increase in muscle protein content are not fully clarified. The purpose of this study was to investigate the effects of MENS on the muscular protein content, intracellular signals, and the expression level of caveolin-3 (Cav-3), tripartite motif-containing 72 (TRIM72) and MM isoenzyme of creatine kinase (CK-MM) in skeletal muscle using cell culture system. C2C12 myotubes on the 7th day of differentiation phase were treated with MENS (intensity: 10-20 microA, frequency: 0.3 Hz, pulse width: 250 ms, stimulation time: 15-120 min). MENS-associated increase in the protein content of myotubes was observed, compared to the untreated control level. MENS upregulated the expression of Cav-3, TRIM72, and CK-MM in myotubes. A transient increase in phosphorylation level of Akt was also observed. However, MENS had no effect on the phosphorylation level of p42/44 extracellular signal-regulated kinase-1/2 and 5’AMP-activated protein kinase. MENS may increase muscle protein content accompanied with a transient activation of Akt and the upregulation of Cav-3 and TRIM72.

scholarly journals HDAC6-Selective Inhibitor Overcomes Bortezomib Resistance in Multiple Myeloma

2021 ◽  
Vol 22 (3) ◽  
pp. 1341
Author(s):  
Sang Wu Lee ◽  
Soo-Keun Yeon ◽  
Go Woon Kim ◽  
Dong Hoon Lee ◽  
Yu Hyun Jeon ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Nuclear Factor Kappa B ◽  
Selective Inhibitor ◽  
Signal Transducer ◽  
Histone Deacetylase 6 ◽  
Cell Growth Inhibition ◽  
Cancer Cell Growth ◽  
Extracellular Signal ◽  
Hdac6 Inhibitor ◽  
Transcription 3

Although multiple myeloma (MM) patients benefit from standard bortezomib (BTZ) chemotherapy, they develop drug resistance, resulting in relapse. We investigated whether histone deacetylase 6 (HDAC6) inhibitor A452 overcomes bortezomib resistance in MM. We show that HDAC6-selective inhibitor A452 significantly decreases the activation of BTZ-resistant markers, such as extracellular signal-regulated kinases (ERK) and nuclear factor kappa B (NF-κB), in acquired BTZ-resistant MM cells. Combination treatment of A452 and BTZ or carfilzomib (CFZ) synergistically reduces BTZ-resistant markers. Additionally, A452 synergizes with BTZ or CFZ to inhibit the activation of NF-κB and signal transducer and activator of transcription 3 (STAT3), resulting in decreased expressions of low-molecular-mass polypeptide 2 (LMP2) and LMP7. Furthermore, combining A452 with BTZ or CFZ leads to synergistic cancer cell growth inhibition, viability decreases, and apoptosis induction in the BTZ-resistant MM cells. Overall, the synergistic effect of A452 with CFZ is more potent than that of A452 with BTZ in BTZ-resistant U266 cells. Thus, our findings reveal the HDAC6-selective inhibitor as a promising therapy for BTZ-chemoresistant MM.

scholarly journals β2-adrenergic receptor agonist counteracts skeletal muscle atrophy and oxidative stress in uremic mice

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Takaaki Higashihara ◽  
Hiroshi Nishi ◽  
Koji Takemura ◽  
Hiroshi Watanabe ◽  
Toru Maruyama ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Adrenergic Receptor ◽  
Culture Media ◽  
Therapeutic Interventions ◽  
Skeletal Muscle Atrophy ◽  
C2c12 Myotubes ◽  
Ros Generation ◽  
Skeletal Muscle Function ◽  
Ros Accumulation ◽  
Β2 Adrenergic Receptor

AbstractIn patients with chronic kidney disease, skeletal muscle dysfunction is associated with mortality. Uremic sarcopenia is caused by ageing, malnutrition, and chronic inflammation, but the molecular mechanism and potential therapeutics have not been fully elucidated yet. We hypothesize that accumulated uremic toxins might exert a direct deteriorative effect on skeletal muscle and explore the pharmacological treatment in experimental animal and culture cell models. The mice intraperitoneally injected with indoxyl sulfate (IS) after unilateral nephrectomy displayed an elevation of IS concentration in skeletal muscle and a reduction of instantaneous muscle strength, along with the predominant loss of fast-twitch myofibers and intramuscular reactive oxygen species (ROS) generation. The addition of IS in the culture media decreased the size of fully differentiated mouse C2C12 myotubes as well. ROS accumulation and mitochondrial dysfunction were also noted. Next, the effect of the β2-adrenergic receptor (β2-AR) agonist, clenbuterol, was evaluated as a potential treatment for uremic sarcopenia. In mice injected with IS, clenbuterol treatment increased the muscle mass and restored the tissue ROS level but failed to improve muscle weakness. In C2C12 myotubes stimulated with IS, although β2-AR activation also attenuated myotube size reduction and ROS accumulation as did other anti-oxidant reagents, it failed to augment the mitochondrial membrane potential. In conclusion, IS provokes muscular strength loss (uremic dynapenia), ROS generation, and mitochondrial impairment. Although the β2-AR agonist can increase the muscular mass with ROS reduction, development of therapeutic interventions for restoring skeletal muscle function is still awaited.

scholarly journals Morphological Evidence of Telocytes in Skeletal Muscle Interstitium of Exercised and Sedentary Rodents

Biomedicines ◽  
2021 ◽  
Vol 9 (7) ◽  
pp. 807
Author(s):  
Silvia Ravalli ◽  
Concetta Federico ◽  
Giovanni Lauretta ◽  
Salvatore Saccone ◽  
Elisabetta Pricoco ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Muscle Atrophy ◽  
Stromal Cells ◽  
Tibialis Anterior Muscle ◽  
Skeletal Muscle Atrophy ◽  
Morphological Evidence ◽  
Double Positive ◽  
Functional Changes ◽  
Cell Niche ◽  
The Relationship

Skeletal muscle atrophy, resulting from states of hypokinesis or immobilization, leads to morphological, metabolic, and functional changes within the muscle tissue, a large variety of which are supported by the stromal cells populating the interstitium. Telocytes represent a recently discovered population of stromal cells, which has been increasingly identified in several human organs and appears to participate in sustaining cross-talk, promoting regenerative mechanisms and supporting differentiation of local stem cell niche. The aim of this morphologic study was to investigate the presence of Telocytes in the tibialis anterior muscle of healthy rats undergoing an endurance training protocol for either 4 weeks or 16 weeks compared to sedentary rats. Histomorphometric analysis of muscle fibers diameter revealed muscle atrophy in sedentary rats. Telocytes were identified by double-positive immunofluorescence staining for CD34/CD117 and CD34/vimentin. The results showed that Telocytes were significantly reduced in sedentary rats at 16 weeks, while rats subjected to regular exercise maintained a stable Telocytes population after 16 weeks. Understanding of the relationship between Telocytes and exercise offers new chances in the field of regenerative medicine, suggesting possible triggers for Telocytes in sarcopenia and other musculoskeletal disorders, promoting adapted physical activity and rehabilitation programmes in clinical practice.

scholarly journals Exercise-induced mitogen-activated protein kinase signalling in skeletal muscle

2004 ◽  
Vol 63 (2) ◽  
pp. 227-232 ◽  
Author(s):  
Yun Chau Long ◽  
Ulrika Widegren ◽  
Juleen R. Zierath
Keyword(s):  
Skeletal Muscle ◽  
Protein Kinase ◽  
Muscle Contraction ◽  
Mitogen Activated Protein Kinase ◽  
Mapk Cascades ◽  
Extracellular Signal ◽  
Mapk Signalling ◽  
Mitogen Activated Protein ◽  
Exercise Induced ◽  
Response To Exercise

Exercise training improves glucose homeostasis through enhanced insulin sensitivity in skeletal muscle. Muscle contraction through physical exercise is a physiological stimulus that elicits multiple biochemical and biophysical responses and therefore requires an appropriate control network. Mitogen-activated protein kinase (MAPK) signalling pathways constitute a network of phosphorylation cascades that link cellular stress to changes in transcriptional activity. MAPK cascades are divided into four major subfamilies, including extracellular signal-regulated kinases 1 and 2, p38 MAPK, c-Jun NH2-terminal kinase and extracellular signal-regulated kinase 5. The present review will present the current understanding of parallel MAPK signalling in human skeletal muscle in response to exercise and muscle contraction, with an emphasis on identifying potential signalling mechanisms responsible for changes in gene expression.

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