Glucocorticoid Receptor Alpha Targets SLC2A4 to Regulate Protein Synthesis and Breakdown in Porcine Skeletal Muscle Cells

In the presence of stress, the hypothalamic-pituitary-adrenal (HPA) axis activity can be enhanced to promote the secretion of a large amount of glucocorticoids (GCs), which play an important role in the anabolism and catabolism of skeletal muscle. When the endogenous and exogenous glucocorticoids are deficient or excessive, the body will produce stress-related resistance and change the protein metabolism. In this study, we investigated the effect of GC receptor GRα on protein breakdown and synthesis in porcine skeletal muscle cells (PSCs). Overexpression of GRα was shown to increase the expression of protein degradation-related genes, while knockdown of GRα decreased the expression of these genes. Additionally, we found a relationship between GRα and solute carrier family 2 member 4 (SLC2A4), SLC2A4 expression level increases when stress occurs, suggesting that increasing SLC2A4 expression can partially alleviate stress-induced damage, and we found that there is a combination between them via luciferase reporter assays, which still needs to be confirmed in further studies.

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MiR-22-3p Inhibits Proliferation and Promotes Differentiation of Skeletal Muscle Cells by Targeting IGFBP3 in Hu Sheep

Animals ◽

10.3390/ani12010114 ◽

2022 ◽

Vol 12 (1) ◽

pp. 114

Author(s):

Shan Wang ◽

Xiukai Cao ◽

Ling Ge ◽

Yifei Gu ◽

Xiaoyang Lv ◽

...

Keyword(s):

Cell Cycle ◽

Skeletal Muscle ◽

Growth And Development ◽

Muscle Cells ◽

Bioinformatic Analysis ◽

C2c12 Cells ◽

Skeletal Muscle Cells ◽

Luciferase Reporter ◽

Reporter System ◽

Hu Sheep

The growth and development of skeletal muscle require a series of regulatory factors. MiRNA is a non-coding RNA with a length of about 22 nt, which can inhibit the expression of mRNA and plays an important role in the growth and development of muscle cells. The role of miR-22-3p in C2C12 cells and porcine skeletal muscle has been reported, but it has not been verified in Hu sheep skeletal muscle. Through qPCR, CCK-8, EdU and cell cycle studies, we found that overexpression of miR-22-3p inhibited proliferation of skeletal muscle cells (p < 0.01). The results of qPCR and immunofluorescence showed that overexpression of miR-22-3p promoted differentiation of skeletal muscle cells (p < 0.01), while the results of inhibiting the expression of miR-22-3p were the opposite. These results suggested that miR-22-3p functions in growth and development of sheep skeletal muscle cells. Bioinformatic analysis with mirDIP, miRTargets, and RNAhybrid software suggested IGFBP3 was the target of miR-22-3p, which was confirmed by dual-luciferase reporter system assay. IGFBP3 is highly expressed in sheep skeletal muscle cells. Overexpression of IGFBP3 was found to promote proliferation of skeletal muscle cells indicated by qPCR, CCK-8, EdU, and cell cycle studies (p < 0.01). The results of qPCR and immunofluorescence experiments proved that overexpression of IGFBP3 inhibited differentiation of skeletal muscle cells (p < 0.01), while the results of interfering IGFBP3 with siRNA were the opposite. These results indicate that miR-22-3p is involved in proliferation and differentiation of skeletal muscle cells by targeting IGFBP3.

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Fiber type conversion alters inactivation of voltage-dependent sodium currents in murine C2C12skeletal muscle cells

AJP Cell Physiology ◽

10.1152/ajpcell.00015.2004 ◽

2004 ◽

Vol 287 (2) ◽

pp. C270-C280 ◽

Cited By ~ 22

Author(s):

Eva Zebedin ◽

Walter Sandtner ◽

Stefan Galler ◽

Julia Szendroedi ◽

Herwig Just ◽

...

Keyword(s):

Skeletal Muscle ◽

Fiber Type ◽

Muscle Fibers ◽

Muscle Cells ◽

The Body ◽

Skeletal Muscle Cells ◽

Prolonged Treatment ◽

Type Conversion ◽

Electrophysiological Properties ◽

Slow Fiber

Each skeletal muscle of the body contains a unique composition of “fast” and “slow” muscle fibers, each of which is specialized for certain challenges. This composition is not static, and the muscle fibers are capable of adapting their molecular composition by altered gene expression (i.e., fiber type conversion). Whereas changes in the expression of contractile proteins and metabolic enzymes in the course of fiber type conversion are well described, little is known about possible adaptations in the electrophysiological properties of skeletal muscle cells. Such adaptations may involve changes in the expression and/or function of ion channels. In this study, we investigated the effects of fast-to-slow fiber type conversion on currents via voltage-gated Na+channels in the C2C12murine skeletal muscle cell line. Prolonged treatment of cells with 25 nM of the Ca2+ionophore A-23187 caused a significant shift in myosin heavy chain isoform expression from the fast toward the slow isoform, indicating fast-to-slow fiber type conversion. Moreover, Na+current inactivation was significantly altered. Slow inactivation less strongly inhibited the Na+currents of fast-to-slow fiber type-converted cells. Compared with control cells, the Na+currents of converted cells were more resistant to block by tetrodotoxin, suggesting enhanced relative expression of the cardiac Na+channel isoform Nav1.5 compared with the skeletal muscle isoform Nav1.4. These results imply that fast-to-slow fiber type conversion of skeletal muscle cells involves functional adaptation of their electrophysiological properties.

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Factors Controlling Movement of Skeletal Muscles

Leonardo ◽

10.1162/leon_a_01028 ◽

2015 ◽

Vol 48 (3) ◽

pp. 270-271

Author(s):

Miranda D. Grounds

Keyword(s):

Skeletal Muscle ◽

Extracellular Matrix ◽

Cell Membrane ◽

Skeletal Muscles ◽

Muscle Cells ◽

The Body ◽

Skeletal Muscle Cells ◽

3 Dimensional

The contraction of specialized skeletal muscle cells results in classic movements of bones and other parts of the body that are vital for life. There is exquisite control over the movement of diverse types of muscles. This paper indicates the way in which skeletal muscles (myofibres) are formed; then factors that contribute to generating the movement are outlined: these include the nerve, sarcomeres, cytoskeleton, cell membrane and the extracellular matrix. The factors controlling the movement of mature myofibres in 3-dimensional tissues in vivo are vastly more complex than for tissue cultured immature muscle cells in an artificial in vitro environment.

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PO-204 Effects of hypoxia and/or endurance exercise on autophagy of skeletal muscle in rats with nutritional obesity

Exercise Biochemistry Review ◽

10.14428/ebr.v1i5.8883 ◽

2018 ◽

Vol 1 (5) ◽

Author(s):

Fangfang Zhao ◽

Wentao Lin ◽

跟 Wen

Keyword(s):

Skeletal Muscle ◽

Endurance Exercise ◽

Blood Lipids ◽

Muscle Cells ◽

Exercise Group ◽

The Body ◽

Skeletal Muscle Cells ◽

High Fat ◽

Group A ◽

Group D

Objective The globalization of obesity has become an important factor threatening human health, and the rational health of the solution has driven the exploration of experts and scholars. For this reason, this experiment uses hypoxia and exercise as interventions for 8 weeks. Changes of autophagy-related factors LC3 mRNA, p62 mRNA and energy regulation factor AMPKα2 mRNA, and cell stress-inducing factor Sestrin2 mRNA after hypoxia and/or combined endurance exercise, and explored the effect of hypoxia endurance exercise on autophagy of skeletal muscle cells To provide a reasonable experimental basis for exploring hypoxic exercise to lose weight and to prevent or reduce autophagy-related diseases. Methods First, a nutritional obese rat model fed with high-fat diet for 8 weeks was constructed and randomly divided into 8 groups: the normoxia group (A), the normoxic group (AE), and 16.3%. Oxygen quiet group (B) and 16.3% hypoxic exercise group (BE), 13.3% hypoxic quiet group (C), 13.3% hypoxic exercise group (CE), 11.3% hypoxic quiet group (D), 11.3% low Oxygen exercise group (DE), 10 in each group, and continued to feed with high fat diet. Secondly, establish a hypoxic and/or endurance exercise model, and the experimental experiment is expected. The rat training program is as follows: the normoxia quiet group does not perform any endurance exercise and other interventions under normoxia; the normoxic exercise group is large. The rats underwent a medium-intensity endurance exercise with a running speed of 20 m/min in a normal oxygen environment for 40 min. Similarly, rats in the hypoxic quiet group underwent continuous hypoxia intervention for 12h in the corresponding hypoxic environment; the hypoxic-binding endurance exercise group was based on the intervention of the hypoxic-quiet group, with a time of 40 min and a running speed of 20 m/ Min's medium-intensity endurance exercise. The frequency of exercise is 5 times a week (every Monday to Friday) for 8 weeks. After the last training, fasting for 24 hours, the rats were sacrificed and sampled. Biochemical indicators were used to measure blood lipids and blood glucose concentration; real-time quantitative PCR was used to detect the expression of autophagy regulators Sestrin2, AMPKɑ2 and autophagy Beclin1 and LC3II mRNA. Results 1.Nutritional obesity rat model: After 8 weeks of high-fat feeding, the body weight, Lee's index, BG, TC, TG and LDL-c concentrations in the high-fat group were significantly increased (P<0.05) 2.Changes in morphology and blood lipids of rats: Compared with group A, the body weight, BG, TC, TG, LDL-c concentrations in the AE group were significantly decreased (P<0.05), and the HDL-c concentration was significantly increased (P<0.05). LDL-c in group D, TG and BD concentrations in group B, group C and group D were significantly decreased (P<0.05), and HDL-c concentrations in groups C and D were significantly increased (P<0.05); Compared with the group, the LDL-c and TG concentrations in the DE group were significantly lower (P<0.05), the BG concentrations in the CE group and the DE group were significantly lower (P<0.05), and the HDL-c concentration in the DE group was significantly increased (P<0.05). ). 3.Real-time quantitative PCR showed that compared with group A, the expression of Sestrin2, Beclin1 and LC3II mRNA in skeletal muscle cells of AE group, C group and D group was significantly increased (P<0.05), and the expression of AMPKɑ2 mRNA in group D was significantly increased. Compared with AE group, the expressions of Beclin1, LC3II and AMPKɑ2 mRNA in CE group and DE group were significantly increased (P<0.05), and the expression of Sestrin2 mRNA in DE group was significantly increased (P<0.05). Conclusions 1.Three different concentrations of hypoxia and / or combined endurance exercise can reduce the body weight of obese rats, improve the blood sugar, blood lipids, hypoxia and exercise in obese rats, the effect of weight loss, blood sugar and blood lipids is more obvious. 2.Endurance exercise, hypoxic exposure, hypoxia combined with endurance exercise can induce autophagy in skeletal muscle cells; and the cumulative stimulation effect of exercise and hypoxia is more prominent than simple endurance exercise and hypoxia exposure. 3.Three different concentrations of hypoxia and/or combined endurance exercise can up-regulate the expression of Sestrin2, AMPKɑ2, Beclin1, and LC3II mRNA, thereby effectively activating and enhancing the autophagy level of skeletal muscle cells in obese rats, especially 11.3% hypoxia. The endurance exercise group has a more pronounced effect.

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Studies on the effects of hypothermia combined with hypoxia on rat skeletal muscle and lipid metabolism based on AMPK/PGC1α pathway

Journal of Orthopaedic Surgery and Research ◽

10.1186/s13018-021-02861-0 ◽

2021 ◽

Vol 16 (1) ◽

Author(s):

Zhang Ruixia ◽

Liu chuanchuan ◽

Guan Lu ◽

Ma Shuang ◽

Zhu Qiang ◽

...

Keyword(s):

Skeletal Muscle ◽

Body Weight ◽

Lipid Metabolism ◽

Muscle Cells ◽

The Body ◽

Skeletal Muscle Cells ◽

Male Rats ◽

Rat Skeletal Muscle ◽

Blank Group ◽

Hypoxia Group

Abstract Aim To explore the effects of hypothermia and hypoxia on rat skeletal muscle and lipid metabolism. Method Forty male rats were randomly divided into blank group, low-temperature group, hypoxia group, and hypothermia combined with hypoxia group. The body weight of the rats was monitored. The changes of Irisin were detected by ELISA, and LDL, HDL, TC, and TG levels in serum were detected by blood biochemistry. Western blot was used to detect the changes of lipid metabolism-related proteins. CCK8 was used to verify the effect of AMPK/PGC1α on the proliferation of rat skeletal muscle cells. Result In the case of cold stimulation and hypoxia, the weight of the rats decreased significantly, and the levels of LDL, HDL, TC, and TG in the serum were abnormal. The activity of fatty acid metabolism factors Irisin, UCP-1, and FABP4 is down-regulated by hypothermia and hypoxia. The activity of fat metabolism-related enzymes, ATGL, HSL, and MGL increased under hypothermia and low oxygen conditions. Hypothermia and hypoxia affected the morphology of skeletal muscle, and AMPK/PGC-1α can regulate the proliferation of skeletal muscle cells. Conclusion Hypothermia and hypoxia can reduce the body weight of rats, and affect the structure of skeletal muscle to promote lipid metabolism through AMPK/PGC-1α signaling pathway.

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Transcriptional Analysis of the Human Cardiac Calsequestrin Gene in Cardiac and Skeletal Myocytes

Journal of Biological Chemistry ◽

10.1074/jbc.m707788200 ◽

2007 ◽

Vol 282 (49) ◽

pp. 35554-35563 ◽

Cited By ~ 13

Author(s):

José Luis Reyes-Juárez ◽

Raúl Juárez-Rubí ◽

Gabriela Rodríguez ◽

Angel Zarain-Herzberg

Keyword(s):

Skeletal Muscle ◽

Transcriptional Activity ◽

Muscle Cells ◽

Skeletal Muscle Cells ◽

Neonatal Rat ◽

Transcriptional Analysis ◽

Proximal Promoter ◽

Luciferase Reporter ◽

E Box ◽

Carg Box

Calsequestrin is the main calcium-binding protein inside the sarcoplasmic reticulum of striated muscle. In mammals, the cardiac calsequestrin gene (casq2) mainly expresses in cardiac muscle and to a minor extent in slow-twitch skeletal muscle and it is not expressed in non-muscle tissues. This work is the first study on the transcriptional regulation of the casq2 gene in cardiac and skeletal muscle cells. The sequence of the casq2 genes proximal promoter (180 bp) of mammals and avians is highly conserved and contains one TATA box, one CArG box, one E-box, and one myocyte enhancer factor 2 (MEF-2) site. We cloned the human casq2 gene 5′-regulatory region into a luciferase reporter expression vector. By functional assays we showed that a construct containing the first 288 bp of promoter was up-regulated during myogenic differentiation of Sol8 cells and had higher transcriptional activity compared with longer constructs. In neonatal rat cardiac myocytes, the larger construct containing 3.2 kb showed the highest transcriptional activity, demonstrating that the first 288 bp are sufficient to confer muscle specificity, whereas distal sequences may act as a cardiac-specific enhancer. Electrophoretic mobility shift assay studies demonstrated that the proximal MEF-2 and CArG box sequences were capable of binding MEF-2 and serum response factor, respectively, whereas the E-box did not show binding properties. Functional studies demonstrated that site-directed mutagenesis of the proximal MEF-2 and CArG box sites significantly decreased the transcription of the gene in cardiac and skeletal muscle cells, indicating that they are important to drive cardiac and skeletal muscle-specific transcription of the casq2 gene.

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