• 운동영양학회지
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• 제16권1호
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• pp.1-9
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• 2012

Long chain fatty acids (LCFAs) are transported into cells via plasma transporters, are activated to fatty acyl-CoA by fatty acyl-CoA synthase (ACS), and enter mitochondria via the carnitine system (CPT1/CACT/CPT2). The mitochondrial carnitine system plays an obligatory role in β-oxidation of LCFAs by catalyzing their transport into the mitochondrial matrix. Fatty acyl-CoAs are oxidized via the β-oxidation pathway, which results in the production of acetyl-CoA. The acetyl-CoA can be imported into the tricarboxylic acid (TCA) cycle for oxidation in the mitochondrial matrix or can be used for malonyl-CoA synthesis by acetyl-CoA carboxylase 2 (ACC2) in the cytoplasm. In skeletal muscle, ACC2 catalyzes the carboxylation of acetyl-CoA to form malonyl-CoA, which is a potent endogenous inhibitor of carnitine palmitoyltransferase 1 (CPT1). Thus, ACC2 indirectly inhibits the influx of fatty acids into the mitochondria. Fatty acid metabolism can also be regulated by malonyl-CoA-mediated inhibition of CPT1.

• 한국축산식품학회지
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• 제40권5호
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• pp.852-859
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• 2020

The muscle stem cells of domestic animals are of interest to researchers in the food and biotechnology industries for the production of cultured meat. For producing cultured meat, it is crucial for muscle stem cells to be efficiently isolated and stably maintained in vitro on a large scale. In the present study, we aimed to optimize the method for the enrichment of pig muscle stem cells using a magnetic-activated cell sorting (MACS) system. Pig muscle stem cells were collected from the biceps femoris muscles of 14 d-old pigs of three breeds [Landrace×Yorkshire×Duroc (LYD), Berkshire, and Korean native pigs] and cultured in skeletal muscle growth medium-2 (SkGM-2) supplemented with epidermal growth factor (EGF), dexamethasone, and a p38 inhibitor (SB203580). Approximately 30% of total cultured cells were nonmyogenic cells in the absence of purification in our system, as determined by immunostaining for cluster of differentiation 56 (CD56) and CD29, which are known markers of muscle stem cells. Interestingly, following MACS isolation using the CD29 antibody, the proportion of CD56⁺/CD29⁺ muscle stem cells was significantly increased (91.5±2.40%), and the proportion of CD56 single-positive nonmyogenic cells was dramatically decreased. Furthermore, we verified that this method worked well for purifying muscle stem cells in the three pig breeds. Accordingly, we found that CD29 is a valuable candidate among the various marker genes for the isolation of pig muscle stem cells and developed a simple sorting method based on a single antibody to this protein.

• Journal of Animal Science and Technology
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• 제54권3호
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• pp.219-226
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• 2012

Gender specificity in muscle growth and development is well known. Genesis of muscle is dependent on proliferation and differentiation potential of resident myogenic satellite cells (MSCs) present in muscle fibers. Multipotential capacity of forming myocyte, osteocyte, and adipocyte like cell makes MSCs a unique stem cell. To understand the molecular mechanism involved in determination of muscle quality due to difference in hormone concentration of different gender of animals, MSCs were isolated from bovine skeletal muscle and cultured in male, female, and castrated serum supplemented media. DNA microarray used consisted of 24,000 spots with 70 mer oligo in each spot. A total of 88 genes were up-regulated and 551 genes were down-regulated by more than two fold. Among up-regulated gene, 33, 34, and 21 genes were found up-regulated in cells grown in male, female, and castrated serum, respectively. Interestingly, male serum showed 4, female 11 and castrated male showed 4 genes expressed highly in each gender. Further study on the highly up-regulated gene may unfold the mystery of gender specificity found in muscle development. Also, the identification of differentially expressed genes in gender-specific serum will add information on infrastructure of bovine genome research.

• Journal of Ginseng Research
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• 제43권4호
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• pp.580-588
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• 2019

Background: Ginsenoside Rg1 has been shown to clear senescence-associated beta-galactosidase (SA-${\beta}$-gal) in cultured cells. It remains unknown whether Rg1 can influence SA-${\beta}$-gal in exercising human skeletal muscle. Methods: To examine SA-${\beta}$-gal change, 12 young men (age $21{\pm}0.2years$) were enrolled in a randomized double-blind placebo controlled crossover study, under two occasions: placebo (PLA) and Rg1 (5 mg) supplementations 1 h prior to a high-intensity cycling (70% $VO_{2max}$). Muscle samples were collected by multiple biopsies before and after cycling exercise (0 h and 3 h). To avoid potential effect of muscle biopsy on performance assessment, cycling time to exhaustion test (80% $VO_{2max}$) was conducted on another 12 participants (age $23{\pm}0.5years$) with the same experimental design. Results: No changes of SA-${\beta}$-gal were observed after cycling in the PLA trial. On the contrary, nine of the 12 participants showed complete elimination of SA-${\beta}$-gal in exercised muscle after cycling in the Rg1 trial (p < 0.05). Increases in apoptotic DNA fragmentation (PLA: +87% vs. Rg1: +133%, p < 0.05) and $CD68^+$ (PLA:+78% vs. Rg1:+121%, p = 0.17) occurred immediately after cycling in both trials. During the 3-h recovery, reverses in apoptotic nuclei content (PLA:+5% vs. Rg1 -32%, p < 0.01) and increases in inducible nitrate oxide synthase and interleukin 6 mRNA levels of exercised muscle were observed only in the Rg1 trial (p < 0.01). Conclusion: Rg1 supplementation effectively eliminates senescent cells in exercising human skeletal muscle and improves high-intensity endurance performance.

• Nutrition Research and Practice
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• 제16권1호
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• pp.14-32
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• 2022

BACKGROUND/OBJECTIVES: Peroxisome proliferator-activated receptor-gamma co-activator-1α (PGC-1α) has a central role in regulating muscle differentiation and mitochondrial metabolism. PGC-1α stimulates muscle growth and muscle fiber remodeling, concomitantly regulating lactate and lipid metabolism and promoting oxidative metabolism. Gynostemma pentaphyllum (Thumb.) has been widely employed as a traditional herbal medicine and possesses antioxidant, anti-obesity, anti-inflammatory, hypolipemic, hypoglycemic, and anticancer properties. We investigated whether G. pentaphyllum extract (GPE) and its active compound, gypenoside L (GL), affect muscle differentiation and mitochondrial metabolism via activation of the PGC-1α pathway in murine C2C12 myoblast cells. MATERIALS/METHODS: C2C12 cells were treated with GPE and GL, and quantitative reverse transcription polymerase chain reaction and western blot were used to analyze the mRNA and protein expression levels. Myh1 was determined using immunocytochemistry. Mitochondrial reactive oxygen species generation was measured using the 2'7'-dichlorofluorescein diacetate assay. RESULTS: GPE and GL promoted the differentiation of myoblasts into myotubes and elevated mRNA and protein expression levels of Myh1 (type IIx). GPE and GL also significantly increased the mRNA expression levels of the PGC-1α gene (Ppargc1a), lactate metabolism-regulatory genes (Esrra and Mct1), adipocyte-browning gene fibronectin type III domain-containing 5 gene (Fndc5), glycogen synthase gene (Gys), and lipid metabolism gene carnitine palmitoyltransferase 1b gene (Cpt1b). Moreover, GPE and GL induced the phosphorylation of AMP-activated protein kinase, p38, sirtuin1, and deacetylated PGC-1α. We also observed that treatment with GPE and GL significantly stimulated the expression of genes associated with the anti-oxidative stress response, such as Ucp2, Ucp3, Nrf2, and Sod2. CONCLUSIONS: The results indicated that GPE and GL enhance exercise performance by promoting myotube differentiation and mitochondrial metabolism through the upregulation of PGC-1α in C2C12 skeletal muscle.

• BMB Reports
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• 제47권2호
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• pp.69-79
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• 2014

$Ca^{2+}$ release from intracellular stores and influx from extracellular reservoir regulate a wide range of physiological functions including muscle contraction and rhythmic heartbeat. One of the most ubiquitous pathways involved in controlled $Ca^{2+}$ influx into cells is store-operated $Ca^{2+}$ entry (SOCE), which is activated by the reduction of $Ca^{2+}$ concentration in the lumen of endoplasmic or sarcoplasmic reticulum (ER/SR). Although SOCE is pronounced in non-excitable cells, accumulating evidences highlight its presence and important roles in skeletal muscle and heart. Recent discovery of STIM proteins as ER/SR $Ca^{2+}$ sensors and Orai proteins as $Ca^{2+}$ channel pore forming unit expedited the mechanistic understanding of this pathway. This review focuses on current advances of SOCE components, regulation and physiologic and pathophysiologic roles in muscles. The specific property and the dysfunction of this pathway in muscle diseases, and new directions for future research in this rapidly growing field are discussed.

• 한국축산식품학회지
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• 제40권4호
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• pp.659-667
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• 2020

Muscle stem cells isolated from domestic animals, including cows and pigs, were recently spotlighted as candidates for the production of alternative protein resources, so-called cultured meat or lab-grown meat. In the present study, we aimed to optimize the in vitro culture conditions for the long-term expansion of pig muscle stem cells via the screening of various signaling molecules. Pig muscle stem cells were collected from the biceps femoris muscles of 3-d-old crossbred pigs (Landrace×Yorkshire×Duroc, LYD) and cultured in minimum essential medium-based growth media. However, the pig muscle stem cells gradually lost their proliferation ability and featured morphologies during the long-term culture over two weeks. To find suitable in vitro culture conditions for an extended period, skeletal muscle growth medium-2, including epidermal growth factor (EGF), dexamethasone, and a p38 inhibitor (SB203580), was used to support the stemness of the pig muscle stem cells. Interestingly, pig muscle stem cells were stably maintained in a long-term culture without loss of the expression of myogenic marker genes as determined by PCR analysis. Immunostaining analysis showed that the stem cells were capable of myogenic differentiation after multiple passaging. Therefore, we found that basal culture conditions containing EGF, dexamethasone, and a p38 inhibitor were suitable for maintaining pig muscle stem cells during expanded culture in vitro. This culture method may be applied for the production of cultured meat and further basic research on muscle development in the pig.

• 한국생물물리학회:학술대회논문집
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• 한국생물물리학회 2003년도 정기총회 및 학술발표회
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• pp.53-53
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• 2003

Calumenin was previously identified as a high affinity Ca$\^$2+/ binding protein in mouse cardiac sarcoplasmic reticulum (SR). For the present study, a 48 kDa skeletal homologue of calumenin was identified by sucrose-density gradient of rabbit skeletal SR membranes, concanavalin A treatment, 2D-gel electrophoresis, $\^$45/Ca$\^$2+/ overlay, Stains-all staining, and MALDI-TOF analysis. We attempted to clone the skeletal calumenin by RT-PCR based on mouse cardiac and human calumenin sequences. The deduced amino acid sequence (315 residues) of the skeletal calumenin showed high identity to mouse cardiac calumenin (90％). As seen in the cardiac calumenin, the deduced sequence contains a 19 amino acid N-terminal signal sequence and a HDEF C-terminal sequence, a putative retrieval signal to ER. Also, the skeletal calumenin contains one N-glycosylation site, three PKC phosphorylation sites, eight casein kinase 2 phosphorylation sites, and 6 EF-hand domains. GST-calumenin showed a conformational change and increased mobility in the presence of Ca$\^$2+/ in SDS-PAGE. Three calumenin interacting proteins (ryanodine receptor 1, glycogen phosphorylase, and phosphofructo kinase) were identified by pull-down assay with GST-calumenin and solubilized SR. All the interactions were Ca$\^$2+/dependent. The present results suggest that calumenin plays an important role in Ca$\^$2+/ homeostasis of muscle cells.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제18권3호
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• pp.488-499
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• 1996

Diabetes mellitus revealed a chronic disorder of lipid, carbohydrate and protein metabolism characterized by insulin deficiency, and a striking tendency toward development of atherosclerosis, microangiopathy, nephropathy, neuropathy and recently cardiomyopathy etc. The mechanism of heart failure in patients with diabetic cardiomyopathy is not clear but diabetic cardiomyopathy usually occurs in persons with long standing diabetes. After diabetes induced in made Sprague- Dawley strain rats by injection of streptozotocin(60mg/kg), cardiac tissue with hematoxylin-eosin and Masson's trichrome stain was examined at 3 days, 1, 2, 4, 6 weeks later under light microscope. The results were obtained as follows : 1. In H&E stain of control group, myocardiac cells were shorter than skeletal muscle cell, which was branched out and connected each other at terminal with striation, intercalated disk and nucleus at center of cell. 2. In MT stain of control group, a few of collagen fibrile were seen at periva scular interstium, but wasn't seen between skeletal muscle fiber, and cardiac muscle was seen in various size. 3. In MT stain of experimental group, increased collagen fiber deposition at perivascular interstiums were seen periodically. 4. In MT stain of experimental group, increased collagen fiber deposition at interstitial matrix between perimyocardiac cells were seen at 3 day, 4 weeks and 6 weeks after DM induction. 5. In H&E stain of experimental group, partial degeneration of myocardiac cells was seen after 4 weeks of DM induction. From above results, streptozotocin induced diabetes mellitus increased collagen around perivascular and between intercellular matrix in heart.

• Clinics in Shoulder and Elbow
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• 제21권2호
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• pp.87-94
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• 2018

Background: Popeye deformity is common after rupture of the biceps muscle's long head tendon. Herein, we report on histological changes in biceps brachii muscles following tenotomy of the long head biceps tendon. Methods: Twelve Sprague-Dawley rats (12-week-old) underwent tenotomy of the long head biceps tendon in the right shoulder. At postoperative weeks 4, 7, and 10, the operative shoulders were removed by detaching the biceps brachii muscle from the glenoid scapula and humerus; the opposite shoulders were removed as controls. H&E staining was performed to elucidate histological changes in myocytes. Oil-red O staining was performed to determine fatty infiltration. Myostatin antibody immunohistochemistry staining was performed as myostatin is expressed by skeletal muscle cells during myogenesis. Results: H&E staining results revealed no changes in muscle cell nuclei. There were no adipocytes detected. Compared with that of the control biceps, the cross-sectional area of the long head biceps was significantly smaller (p=0.00). Statistical changes in the total extent of the 100 muscle cells were significant (p=0.00). Oil-red O staining revealed no fatty infiltration. Myostatin antibody immunohistochemical staining revealed no significant difference between the two sides. Conclusions: Muscular changes after tenotomy of the long head biceps included a decrease in the size of the individual muscle cells and in relative muscle mass. There were no changes observed in muscle cell nuclei and no fatty infiltration. Moreover, there were no changes detected by myostatin antibody immunohistochemistry assay.