scholarly journals Optimization of an in vitro bioassay to monitor growth and formation of myotubes in real time

2016 ◽  
Vol 36 (3) ◽  
Author(s):  
Sylvia M. Murphy ◽  
Maeve Kiely ◽  
Philip M. Jakeman ◽  
Patrick A. Kiely ◽  
Brian P. Carson
Keyword(s):  
Skeletal Muscle ◽  
Real Time ◽  
Muscle Protein ◽  
In Vitro Bioassay ◽  
Protein Balance ◽  
Proliferation And Differentiation

In the present paper we have developed, described and validated an in vitro bioassay to monitor skeletal muscle proliferation and differentiation. We have also demonstrated the use of this assay to evaluate factors which may affect muscle protein balance.

scholarly journals Skeletal muscle protein balance in mTOR heterozygous mice in response to endotoxin and leucine

2010 ◽  
Vol 24 (S1) ◽  
Author(s):  
Charles H. Lang ◽  
Robert A. Frost ◽  
Sarah K. Bronson ◽  
Christopher J. Lynch ◽  
Thomas C. Vary
Keyword(s):  
Skeletal Muscle ◽  
Muscle Protein ◽  
Skeletal Muscle Protein ◽  
Protein Balance

scholarly journals miR-194-5p negatively regulates the proliferation and differentiation of rabbit skeletal muscle satellite cells

2020 ◽  
Author(s):  
Yu Shi ◽  
Xudong Mao ◽  
Mingcheng Cai ◽  
Shenqiang Hu ◽  
Xiulan Lai ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Satellite Cells ◽  
Mammalian Species ◽  
Muscle Growth ◽  
Luciferase Reporter ◽  
Stem Cell Population ◽  
Muscle Satellite Cells ◽  
Skeletal Muscle Satellite Cells ◽  
Proliferation And Differentiation

Abstract Skeletal muscle satellite cells (SMSCs), also known as a multipotential stem cell population, play a crucial role during muscle growth and regeneration. In recent years, numerous miRNAs have been associated with the proliferation and differentiation of SMSCs in a number of mammalian species; however, the regulatory mechanisms of miR-194-5p in rabbit SMSCs still remain scarce. In this study, miR-194-5p was first observed to be highly expressed in the rabbit leg muscle. Furthermore, both the mimics and inhibitor of miR-194-5p were used to explore its role in the proliferation and differentiation of rabbit SMSCs cultured in vitro. Results from both EdU and CCK8 assays showed that miR-194-5p inhibited the proliferation of SMSCs. Meanwhile, Mef2c was identified as a target gene of miR-194-5p based on the dual-luciferase reporter assay results. In addition, upregulation of miR-194-5p decreased the expression levels of Mef2c and MyoG during rabbit SMSCs differentiation on Days 3 and 7 of in vitro culture. Taken together, these data demonstrated that miR-194-5p negatively regulates the proliferation and differentiation of rabbit SMSCs by targeting Mef2c.

scholarly journals Reduced skeletal muscle protein balance in paediatric Crohn's disease

2020 ◽  
Vol 39 (4) ◽  
pp. 1250-1257 ◽  
Author(s):  
Amanda Davies ◽  
Aline Nixon ◽  
Rafeeq Muhammed ◽  
Kostas Tsintzas ◽  
Sian Kirkham ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Crohn’S Disease ◽  
Crohn's Disease ◽  
Muscle Protein ◽  
Skeletal Muscle Protein ◽  
Protein Balance ◽  
Paediatric Crohn’S Disease

scholarly journals Chlorella vulgaris Modulates Genes and Muscle-Specific microRNAs Expression to Promote Myoblast Differentiation in Culture

2019 ◽  
Vol 2019 ◽  
pp. 1-16 ◽  
Author(s):  
Nurhazirah Zainul Azlan ◽  
Yasmin Anum Mohd Yusof ◽  
Ekram Alias ◽  
Suzana Makpol
Keyword(s):  
Skeletal Muscle ◽  
Chlorella Vulgaris ◽  
Muscle Regeneration ◽  
Human Skeletal Muscle ◽  
The Elderly ◽  
Myoblast Differentiation ◽  
Gradual Decline ◽  
Proliferation And Differentiation ◽  
And Function

Background. Loss of skeletal muscle mass, strength, and function due to gradual decline in the regeneration of skeletal muscle fibers was observed with advancing age. This condition is known as sarcopenia. Myogenic regulatory factors (MRFs) are essential in muscle regeneration as its activation leads to the differentiation of myoblasts to myofibers. Chlorella vulgaris is a coccoid green eukaryotic microalga that contains highly nutritious substances and has been reported for its pharmaceutical effects. The aim of this study was to determine the effect of C. vulgaris on the regulation of MRFs and myomiRs expression in young and senescent myoblasts during differentiation in vitro. Methods. Human skeletal muscle myoblast (HSMM) cells were cultured and serial passaging was carried out to obtain young and senescent cells. The cells were then treated with C. vulgaris followed by differentiation induction. The expression of Pax7, MyoD1, Myf5, MEF2C, IGF1R, MYOG, TNNT1, PTEN, and MYH2 genes and miR-133b, miR-206, and miR-486 was determined in untreated and C. vulgaris-treated myoblasts on Days 0, 1, 3, 5, and 7 of differentiation. Results. The expression of Pax7, MyoD1, Myf5, MEF2C, IGF1R, MYOG, TNNT1, and PTEN in control senescent myoblasts was significantly decreased on Day 0 of differentiation (p<0.05). Treatment with C. vulgaris upregulated Pax7, Myf5, MEF2C, IGF1R, MYOG, and PTEN in senescent myoblasts (p<0.05) and upregulated Pax7 and MYOG in young myoblasts (p<0.05). The expression of MyoD1 and Myf5 in young myoblasts however was significantly decreased on Day 0 of differentiation (p<0.05). During differentiation, the expression of these genes was increased with C. vulgaris treatment. Further analysis on myomiRs expression showed that miR-133b, miR-206, and miR-486 were significantly downregulated in senescent myoblasts on Day 0 of differentiation which was upregulated by C. vulgaris treatment (p<0.05). During differentiation, the expression of miR-133b and miR-206 was significantly increased with C. vulgaris treatment in both young and senescent myoblasts (p<0.05). However, no significant change was observed on the expression of miR-486 with C. vulgaris treatment. Conclusions. C. vulgaris demonstrated the modulatory effects on the expression of MRFs and myomiRs during proliferation and differentiation of myoblasts in culture. These findings may indicate the beneficial effect of C. vulgaris in muscle regeneration during ageing thus may prevent sarcopenia in the elderly.

Mechano-growth factor peptide, the COOH terminus of unprocessed insulin-like growth factor 1, has no apparent effect on myoblasts or primary muscle stem cells

2014 ◽  
Vol 306 (2) ◽  
pp. E150-E156 ◽  
Author(s):  
Mara Fornaro ◽  
Aaron C. Hinken ◽  
Saul Needle ◽  
Erding Hu ◽  
Anne-Ulrike Trendelenburg ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Stem Cells ◽  
Amino Acid ◽  
Growth Factor ◽  
Muscle Stem Cells ◽  
Mechano Growth Factor ◽  
Primary Mouse ◽  
Proliferation And Differentiation ◽  
Vitro Effect

A splice form of IGF-1, IGF-1Eb, is upregulated after exercise or injury. Physiological responses have been ascribed to the 24-amino acid COOH-terminal peptide that is cleaved from the NH3-terminal 70-amino acid mature IGF-1 protein. This COOH-terminal peptide was termed “mechano-growth factor” (MGF). Activities claimed for the MGF peptide included enhancing muscle satellite cell proliferation and delaying myoblast fusion. As such, MGF could represent a promising strategy to improve muscle regeneration. Thus, at our two pharmaceutical companies, we attempted to reproduce the claimed effect of MGF peptides on human and mouse muscle myoblast proliferation and differentiation in vitro. Concentrations of peptide up to 500 ng/ml failed to increase the proliferation of C2C12 cells or primary human skeletal muscle myoblasts. In contrast, all cell types exhibited a proliferative response to mature IGF-1 or full-length IGF-1Eb. MGF also failed to inhibit the differentiation of myoblasts into myotubes. To address whether the response to MGF was lost in these tissue culture lines, we measured proliferation and differentiation of primary mouse skeletal muscle stem cells exposed to MGF. This, too, failed to demonstrate a significant effect. Finally, we tested whether MGF could alter a separate documented in vitro effect of the peptide, activation of p-ERK, but not p-Akt, in cardiac myocytes. Although a robust response to IGF-1 was observed, there were no demonstrated activating responses from the native or a stabilized MGF peptide. These results call in to question whether there is a physiological role for MGF.

scholarly journals Effects of potassium deficiency on growth and protein synthesis in skeletal muscle and the heart of rats

1989 ◽  
Vol 62 (2) ◽  
pp. 269-284 ◽  
Author(s):  
Inge Dôrup ◽  
Torben Clausen
Keyword(s):  
Skeletal Muscle ◽  
Protein Synthesis ◽  
Muscle Protein ◽  
Control Level ◽  
Inhibitory Effect ◽  
Potassium Deficiency ◽  
Skeletal Muscle Protein ◽  
K Deficiency

The effects of potassium deficiency on growth, K content and protein synthesis have been compared in 4–13-week-old rats. When maintained on K-deficient fodder (1 mmol/kg) rats ceased to grow within a few days, and the incorporation of [3H]leucine into skeletal muscle protein in vivo was reduced by 28–38%. Pair-feeding experiments showed that this inhibition was not due to reduced energy intake. Following 14 d on K-deficient fodder, there was a further reduction (39–56 %) in the incorporation of [3H]leucine into skeletal muscle protein, whereas the incorporation into plasma, heart and liver proteins was not affected. The accumulation of the non-metabolized amino acid α-aminoisobutyric acid in the heart and skeletal muscles was not reduced. The inhibitory effect of K deficiency on 3H-labelling of muscle protein was seen following intraperitoneal (10–240 min) as well as intravenous (10 min) injection of [3H]leucine. In addition, the incorporation of [3H]phenylalanine into skeletal muscle protein was reduced in K-depleted animals. Following acute K repletion in vivo leading to complete normalization of muscle K content, the incorporation of [3H]leucine into muscle protein showed no increase within 2 h, but reached 76 and 104% of the control level within 24 and 72 h respectively. This was associated with a rapid initial weight gain, but normal body-weight was not reached until after 7 weeks of K repletion. Following 7 d on K-deficient fodder the inhibition of growth and protein synthesis was closely correlated with the K content of the fodder (1–40 mmol/kg) and significant already at modest reductions in muscle K content. In vitro experiments with soleus muscle showed a linear relationship between the incorporation of [3H]leucine into muscle protein and K content, but the sensitivity to cellular K deficiency induced in vitro was much less pronounced than that induced in vivo. Thus, in soleus and extensor digitorum longus (EDL) muscles prepared from K-deficient rats, the incorporation of [3H]leucine was reduced by 30 and 47 % respectively. This defect was completely restored by 24 h K repletion in vivo. It is concluded that in the intact organism protein synthesis and growth are very sensitive to dietary K deficiency and that this can only partly be accounted for by the reduction in cellular K content per se. The observations emphasize the need for adequate K supplies to ensure optimum utilization of food elements for protein synthesis and growth.

Tumor necrosis factor induces skeletal muscle protein breakdown in rats

1991 ◽  
Vol 260 (5) ◽  
pp. E727-E730 ◽  
Author(s):  
M. N. Goodman
Keyword(s):  
Skeletal Muscle ◽  
Tumor Necrosis Factor ◽  
Tumor Necrosis ◽  
Muscle Protein ◽  
Nitrogen Excretion ◽  
Protein Breakdown ◽  
Skeletal Muscle Protein ◽  
Muscle Protein Breakdown ◽  
Necrosis Factor

The metabolic response to infection includes loss of lean tissue and increased nitrogen excretion. The loss of muscle tissue during infection results in large part from accelerated skeletal muscle protein breakdown. Recent studies suggest that macrophage-derived products secreted during infection may signal increased muscle proteolysis. To test this, in the present report the ability of interleukin (IL-1) and tumor necrosis factor (TNF) to enhance muscle proteolysis was examined. Young rats were injected intravenously with either recombinant human IL-1 or TNF. For comparison some rats were injected with bacterial endotoxin. Eight hours after each treatment, the extensor digitorum longus muscles were isolated and incubated in vitro to assess muscle proteolysis by measuring tyrosine and 3-methyl-L-histidine release by the incubated muscles. Treatment of rats with either IL-1, TNF, or endotoxin all induced fever, increased serum lactate, and reduced serum zinc levels. Despite similar metabolic changes, muscle proteolysis responded differently. As expected, endotoxin treatment enhanced muscle protein breakdown, whereas IL-1 treatment was without effect. On the other hand, TNF was effective in accelerating muscle protein breakdown. TNF addition in vitro failed to enhance muscle proteolysis by incubated muscles, suggesting that its effects may be mediated in an indirect manner; however, a direct mode of action cannot yet be ruled out. Overall, the data indicate that the acute administration of TNF can signal increased muscle proteolysis similar to that observed during infection.

scholarly journals Spexin Promotes the Proliferation and Differentiation of C2C12 Cells In Vitro—The Effect of Exercise on SPX and SPX Receptor Expression in Skeletal Muscle In Vivo

Genes ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 81
Author(s):  
Natalia Leciejewska ◽  
Ewa Pruszyńska-Oszmałek ◽  
Karolina Mielnik ◽  
Maciej Głowacki ◽  
Tomasz P. Lehmann ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Receptor Expression ◽  
C2c12 Cells ◽  
Receptor Subtype ◽  
Galanin Receptor ◽  
Differentiation Markers ◽  
Proliferation And Differentiation ◽  
The Impact

SPX (spexin) and its receptors GalR2 and GalR3 (galanin receptor subtype 2 and galanin receptor subtype 3) play an important role in the regulation of lipid and carbohydrate metabolism in human and animal fat tissue. However, little is still known about the role of this peptide in the metabolism of muscle. The aim of this study was to determine the impact of SPX on the metabolism, proliferation and differentiation of the skeletal muscle cell line C2C12. Moreover, we determined the effect of exercise on the SPX transduction pathway in mice skeletal muscle. We found that increased SPX, acting via GalR2 and GalR3 receptors, and ERK1/2 phosphorylation stimulated the proliferation of C2C12 cells (p < 0.01). We also noted that SPX stimulated the differentiation of C2C12 by increasing mRNA and protein levels of differentiation markers Myh, myogenin and MyoD (p < 0.01). SPX consequently promoted myoblast fusion into the myotubule (p < 0.01). Moreover, we found that, in the first stage (after 2 days) of myocyte differentiation, GalR2 and GalR3 were involved, whereas in the last stage (day six), the effect of SPX was mediated by the GalR3 isoform. We also noted that exercise stimulated SPX and GalR2 expression in mice skeletal muscle as well as an increase in SPX concentration in blood serum. These new insights may contribute to a better understanding of the role of SPX in the metabolism of skeletal muscle.

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