• Food Science of Animal Resources
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• v.43 no.4
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• pp.563-579
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• 2023

Myogenesis and adipogenesis are the important processes determining the muscle growth and fat accumulation livestock, which ultimately affecting their meat quality. Hanwoo is a popular breed and its meat has been exported to other countries. The objective of this study was to compare the myogenesis and adipogenesis properties in satellite cells, and meat quality between Hanwoo and Vietnamese yellow cattle (VYC). Same 28-months old Hanwoo (body weight: 728±45 kg) and VYC (body weight: 285±36 kg) steers (n=10 per breed) were used. Immediately after slaughter, tissue samples were collected from longissimus lumborum (LL) muscles for satellite cells isolation and assays. After 24 h post-mortem, LL muscles from left carcass sides were collected for meat quality analysis. Under the same in vitro culture condition, the proliferation rate was higher in Hanwoo compared to VYC (p<0.05). Fusion index was almost 3 times greater in Hanwoo (42.17%), compared with VYC (14.93%; p<0.05). The expressions of myogenesis (myogenic factor 5, myogenic differentiation 1, myogenin, and myogenic factor 6)- and adipogenesis (peroxisome proliferator-activated receptor gamma)-regulating genes, and triglyceride content were higher in Hanwoo, compared with VYC (p<0.05). Hanwoo beef had a higher intramuscular fat and total monounsaturated fatty acids contents than VYC beef (p<0.05). Whilst, VYC meat had a higher CIE a* and total polyunsaturated fatty acids content (p<0.05). Overall, there was a significant difference in the in vitro culture characteristics and genes expression of satellite cells, and meat quality between the Hanwoo and VYC.

• Animal Bioscience
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• v.34 no.8
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• pp.1392-1402
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• 2021

Objective: The growth rate of pigs is related to differentiation and proliferation of muscle cells, which are regulated by growth factors and expression of growth-related genes. Thus, the objective of this study was to establish optimal culture conditions for Jeju black pig (JBP) muscle cells and determine the relationship of various factors involved in muscle growth with the proliferation of JBP muscle cells. Methods: Muscles were taken from the femur skeletal muscle of JBP embryos. After isolation of the muscle cells, cells were cultured in a 6-well plate under four different culture conditions to optimize culture conditions for JBP muscle cells. To analyze proliferation rate of JBP muscle cells, these muscle cells were seeded into 6-well plates at a density of 1.5×10⁵ cells per well and cultured for 3 days. Western blot and quantitative real-time polymerase chain reaction were applied to verify the myogenic differentiation 1 (MyoD) expression and growth-related gene expression in JBP muscle cells, respectively. Results: We established a muscle cell line from JBP embryos and optimized its culture conditions. These muscle cells were positive for MyoD, but not for paired box 7. The proliferation rate of these muscle cells was significantly higher in a culture medium containing bFGF and epidermal growth factor + basic fibroblast growth factor (EGF+bFGF) than that without a growth factor or containing EGF alone. Treatment with EGF and bFGF significantly induced the expression of MyoD protein, an important transcription factor in muscle cells. Moreover, we checked the changes of expression of growth-related genes in JBP muscle cells by presence or absence of growth factors. Expression level of collagen type XXI alpha 1 gene was changed only when EGF and bFGF were added together to culture media for JBP muscle cells. Conclusion: Concurrent use of EGF and bFGF increased the expression of MyoD protein, thus regulating the proliferation of JBP muscle cells and the expression of growth-related genes.

• Animal Bioscience
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• v.36 no.12
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• pp.1775-1784
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• 2023

Objective: The aim of this study was to reveal the role and regulatory mechanism of miR-188-5p in the proliferation and differentiation of goat muscle satellite cells. Methods: Goat skeletal muscle satellite cells isolated in the pre-laboratory were used as the test material. First, the expression of miR-188-5p in goat muscle tissues at different developmental stages was detected by quantitative reverse transcription polymerase chain reaction (qRT-PCR). In addition, miR-188-5p was transfected into goat skeletal muscle satellite cells by constructing mimics and inhibitors of miR-188-5p, respectively. The changes of differentiation marker gene expression were detected by qPCR method. Results: It was highly expressed in adult goat latissimus dorsi and leg muscles, goat fetal skeletal muscle, and at the differentiation stage of muscle satellite cells. Overexpression and interference of miR-188-5p showed that miR-188-5p inhibited the proliferation and promoted the differentiation of goat muscle satellite cells. Target gene prediction and dual luciferase assays showed that miR-188-5p could target the 3'untranslated region of the calcium/calmodulin dependent protein kinase II beta (CAMK2B) gene and inhibit luciferase activity. Further functional studies revealed that CAMK2B promoted the proliferation and inhibited the differentiation of goat muscle satellite cells, whereas si-CAMK2B restored the function of miR-188-5p inhibitor. Conclusion: These results suggest that miR-188-5p inhibits the proliferation and promotes the differentiation of goat muscle satellite cells by targeting CAMK2B. This study will provide a theoretical reference for future studies on the molecular mechanisms of skeletal muscle development in goats.

• Food Science of Animal Resources
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• v.30 no.5
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• pp.842-850
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• 2010

Sex steroids are known to be involved in skeletal muscle development (anabolic effect) and are frequently used in medicines. It has been known that pork contains a variety of steroids that are mainly synthesized in the gonads (testis and ovary). Thus, the present study was conducted to evaluate the effects of anabolic steroids of pork on the proliferation and differentiation of myogenic satellite cells (MSC). Three different methods (M1, M2, and M3) were developed for the isolation and purification of steroids from porcine tissues. Among three extraction methods that we developed, M3 was the best method with respect to the quantities of steroids and the induction of MSC proliferation. Hormonal analysis showed that the steroid hormone levels were the highest in muscle and fat of intact male than those of castrated males and females. In addition, the highest serum levels of nandrolone and testosterone were detected in intact males, whereas estrone and $17{\beta}$-estradiol levels were similar in the entire experimental serum samples. Expression of androgen receptor (AR), myoD, desmin, and myogenin in bovine muscle cells were significantly up-regulated by the treatment of steroid extracts. The highest increas of myogenin and AR mRNA abundance were observed in the MSCs treated with M3 extract (p<0.001). Altogether, the present research showed the positive effect of steroids on MSC proliferation and differentiation in vitro. These results would certainly imply a beneficial effect of pork consumption on human muscle development.

• BMB Reports
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• v.51 no.7
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• pp.350-355
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• 2018

HnRNPK is a multifunctional protein that participates in chromatin remodeling, transcription, RNA splicing, mRNA stability and translation. Here, we uncovered the function of hnRNPK in regulating the proliferation and differentiation of myoblasts. hnRNPK was mutated in the C2C12 myoblast cell line using the CRISPR/Cas9 system. A decreased proliferation rate was observed in hnRNPK-mutated cells, suggesting an impaired proliferation phenotype. Furthermore, increased G2/M phase, decreased S phase and increased sub-G1 phase cells were detected in the hnRNPK-mutated cell lines. The expression analysis of key cell cycle regulators indicated mRNA of Cyclin A2 was significantly increased in the mutant myoblasts compared to the control cells, while Cyclin B1, Cdc25b and Cdc25c were decreased sharply. In addition to the myoblast proliferation defect, the mutant cells exhibited defect in myotube formation. The myotube formation marker, myosin heavy chain (MHC), was decreased sharply in hnRNPK-mutated cells compared to control myoblasts during differentiation. The deficiency in hnRNPK also resulted in the repression of Myog expression, a key myogenic regulator during differentiation. Together, our data demonstrate that hnRNPK is required for myoblast proliferation and differentiation and may be an essential regulator of myoblast function.

• Journal of Biomedical Engineering Research
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• v.31 no.1
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• pp.81-86
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• 2010

Laser irradiation is known to affect various tissues such as skin, bone, nerve, and skeletal muscle. Laser irradiation promotes ATP synthesis, facilitates wound healing, and stimulates cell proliferation and angiogenesis. In skeletal muscle, laser irradiation is related to the proliferation of skeletal muscle satellite cells. Normal skeletal muscle contains remodeling capacity from myogenic cells that are derived from mononuclear satellite cells. Their processes are activated by the expression of genes related with myogenesis such as muscle-specific transcription factors (MyoD and Myf5) and VEGF (vascular endothelial growth factor). In this study, we hypothesized that laser irradiation would enhance and regulate muscle cell proliferation and regeneration through modulation of the gene expressions related with the differentiation of skeletal muscle satellite cells. $C_2C_{12}$ myoblastic cells were exposed to continuous/non-continuous laser irradiation (660nm/808nm) for 10 minutes daily for either 1 day or 5 days. After laser irradiation, cell proliferation and gene expression (MyoD, Myf5, VEGF) were quantified. Continuous 660nm laser irradiation significantly increased cell proliferation and gene expression compared to control, continuous 808nm laser irradiation, and non-continuous 660nm laser irradiation groups. These results indicate that continuous 660nm laser irradiation can be applied to the treatment and regeneration of skeletal muscle tissue.

• Journal of Korean Medicine for Obesity Research
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• v.15 no.1
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• pp.38-44
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• 2015

Objective: Skeletal muscle is a crucial tissue from the perspectives of mitochondrial dysfunction and insulin resistance, it is formed by myogenesis which is dynamic multistep process to be myotubes. The authors could found that root of Atractylodes macrocephala Koidzumi (Atractylodis Rhizoma Alba, ARA) enhanced glucose and lipid metabolism in C2C12 myotubes via mitochondrial regulation. However its action in myogenesis process is not known. The aim of this work was the study of ARA on proliferation, differentiation and hypertrophy in C2C12 cells. Methods: To study proliferation phase, cells were incubated in growth medium with or without ARA (0.2 or 1.0 mg/ml) for 24 hours. To examine differentiation, at 70% confluence, cells were transferred in differentiation medium both with/without ARA (0.2 or 1.0 mg/ml) for 96 hours. And after 72 hours of differentiation, cells were treated with or without ARA (0.2 or 1.0 mg/ml) for 24 hours, the genesis of hypertrophy in myotubes were analyzed. Results: In proliferation phase, ARA could make difference in morphologic examination. In differentiation phase, it also made morphologic difference furthermore ARA (1.0 mg/ml) increased mRNA expressions of Myogenic regulatory factors and muscle-specific proteins synthesis. In late differentiation, ARA induced hypertrophic morphological changes in neo-formed myotubes. Conclusions: ARA might control cell cycle promoting myogenesis and hypertrophy in C2C12 cells.

• Journal of Animal Reproduction and Biotechnology
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• v.37 no.1
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• pp.17-26
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• 2022

Alpha-linolenic acid is an important polyunsaturated fatty acid that exhibits anticancer, anti-inflammatory, and antioxidative effects. In this study, we investigated the protective effects of alpha-linolenic acid on the cell proliferation and differentiation of C2C12 cells under essential amino acid-deficient conditions. Different concentrations of alpha-linolenic acid and essential amino acids were added to the growth and differentiation media. The concentrations of 10 µM of alpha-linolenic acid and 2% essential amino acid were chosen for subsequent experiments. Supplementation with alpha-linolenic acid and essential amino acids improved the proliferation and differentiation of C2C12 cells and significantly increased the mRNA levels of catalase, superoxide dismutase, B-cell lymphoma-2, and beclin-1 as well as the protein levels of PPARγ coactivator-1α compared to those in the controls. Moreover, supplementation with alpha-linolenic acid and essential amino acids reduced the levels of phosphorylated H2A.X variant histone, Bcl-2-associated X, p53, and light chain 3 during C2C12 cell proliferation, and increased the expression levels of myogenic factors 4 (myogenin) and 5 during C2C12 cell differentiation. Overall, we determined that alpha-linolenic acid and essential amino acids maintained the cell proliferation and differentiation of C2C12 cells via their anti-oxidative, anti-apoptotic, and anti-autophagic effects.

• Reproductive and Developmental Biology
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• v.37 no.4
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• pp.219-224
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• 2013

Muscular satellite cell (SC), which is stem cell of postnatal pig, is an important for study of differentiation into adipogenesis, myogenesis, and osteoblastogenesis. In this study, we isolated and examined from pig muscle tissue to determine capacity in proliferate, differentiate, and expression of various genes. Porcine satellite cells (PSC) were isolated from semimembranosus (SM) muscles of 90~100 days old pigs according to standard conditions. The cell proliferation increased in multi-potent cell by Masson's, oil red O, and Alizarin red staining respectively. We performed the expression levels of differentiation related genes using real-time PCR. We found that the differentiation into adipocyte increased expression levels of both fatty acid binding protein 4 (FABP4) and peroxisome proliferator-activated receptor gamma ($PPAR{\gamma}$) genes (p<0.01). Myocyte increased the expression levels of the myosin heavy chain (MHC), myogenic factor 5 (Myf5), myogenic regulatory factor (MyoD), and Myogenic factor 4 (myogenin) (p<0.01). Osteoblast increased the expression levels of alkaline phosphatase (ALP) (p<0.01). Finally, porcine satellite cells were induced to differentiate towards adipogenic, myogenic, and osteoblastogenic lineages. Our results suggest that muscle satellite cell in porcine may influence cell fate. Understanding the progression of PSC may lead to improved strategies for augmenting meat quality.

• Animal Bioscience
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• v.36 no.12
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• pp.1889-1897
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• 2023

Objective: 'Cultured meat' has been suggested as means of solving the problems associated with overpopulation and gas emissions. Satellite cells are a major component in the production of cultured meat; however, these cells cannot be maintained in vitro over long periods. Fibronectin is a glycoprotein that affects biological processes such as cell adhesion, differentiation, and migration. Unfortunately, the characteristics of porcine satellite cells grown in a long-term culture when exposed to fibronectin-coated dishes are unknown. The objective of this study was to investigate the appropriate concentration of fibronectin coated dishes for proliferation and maintenance of porcine satellite cells at long-term culture. Methods: In this study, we isolated the satellite cells and fibroblast cells with pre-plating method. We next analyzed the cell doubling time, cell cycle, and rate of expressed paired box 7 (Pax7) and myogenic differentiation 1 (MyoD1) in porcine satellite cells cultured with 20 ㎍/mL of fibronectin-, gelatin-, and non-coated dishes at early and late passage. We then analyzed the proliferation of porcine satellite cells with various concentrations of mixed gelatin/fibronectin. We next determined the optimal concentration of fibronectin that would encourage proliferation and maintenance of porcine satellite cells in a long-term culture. Results: Doubling time was lowest when 20 ㎍/mL of fibronectin was used (as tested during an early and late passage). Levels of expressed Pax7 and MyoD1, assessed using immunocytochemistry, were highest in cells grown using fibronectin-coated dishes. The proliferation of gelatin/fibronectin mixed coatings had no significant effect on porcine satellite cells. The concentration of 5 ㎍/mL fibronectin coated dishes showed the lowest doubling time and maintained expression of Pax7. Conclusion: Fibronectin with 5㎍/mL effectively maintains porcine satellite cells, a discovery that will be of interest to those developing the next generation of artificial meats.