• Journal of Ginseng Research
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• v.46 no.3
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• pp.454-463
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• 2022

Background: Gintonin-enriched fraction (GEF), a non-saponin fraction of ginseng, is a novel glycolipoprotein rich in hydrophobic amino acids. GEF has recently been shown to regulate lipid metabolism and browning in adipocytes; however, the mechanisms underlying its effects on energy metabolism and whether it affects sarcopenic obesity are unclear. We aimed to evaluate the effects of GEF on skeletal muscle atrophy in high-fat diet (HFD)-induced obese mice. Methods: To examine the effect of GEF on sarcopenic obesity, 4-week-old male ICR mice were used. The mice were divided into four groups: chow diet (CD), HFD, HFD supplemented with 50 mg/kg/day GEF, or 150 mg/kg/day GEF for 6 weeks. We analyzed body mass gain and grip strength, histological staining, western blot analysis, and immunofluorescence to quantify changes in sarcopenic obesity-related factors. Results: GEF inhibited body mass gain while HFD-fed mice gained 22.7 ± 2.0 g, whereas GEF-treated mice gained 14.3 ± 1.2 g for GEF50 and 11.8 ± 1.6 g for GEF150 by downregulating adipogenesis and inducing lipolysis and browning in white adipose tissue (WAT). GEF also enhanced mitochondrial biogenesis threefold in skeletal muscle. Furthermore, GEF-treated skeletal muscle exhibited decreased expression of muscle-specific atrophic genes, and promoted myogenic differentiation and increased muscle mass and strength in a dose-dependent manner (p < 0.05). Conclusion: These findings indicate that GEF may have potential uses in preventing sarcopenic obesity by promoting energy expenditure and attenuating skeletal muscle atrophy.

• Nutrition Research and Practice
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• v.16 no.1
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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.

• Asian-Australasian Journal of Animal Sciences
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• v.24 no.5
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• pp.685-695
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• 2011

Satellite cells are skeletal muscle progenitor/stem cells that reside between the basal lamina and plasma membranes of skeletal fibers in vivo. These cells can give rise to both myogenic and adipogenic cells. Given the possible role for differentiation of satellite cells into adipocytes in marbling and in some pathological disorders like sarcopenia, knowledge of the proteins involved in such process remains obscure. Using two-dimensional polyacrylamide gel electrophoresis coupled with mass spectrometry, we investigated the proteins that are differentially expressed during adipogenic differentiation of satellite cells from bovine longissimus muscle. Our proteome mapping strategy to identify the differentially expressed intracellular proteins during adipogenic differentiation revealed a total of 25 different proteins. The proteins up-regulated during adipogenic differentiation of satellite cells like Cathepsin H precursor, Retinal dehydrogenase 1, Enoyl-CoA hydratase, Ubiquinol-cytochrome-c reductase, T-complex protein 1 subunit beta and ATP synthase D chain were found to be associated with lipid metabolism. The down-regulated proteins like LIM protein, annexin proteins, cofilin-1, Rho GDP-dissociation inhibitor 1 and septin-2, identified in the present study were found to be associated with myogenesis. These results clearly demonstrate that the adipogenic conversion of muscle satellite cells is associated with the up-regulated and down-regulated proteins involved in adipogenesis and myogenesis respectively.

• Journal of Animal Science and Technology
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• v.63 no.4
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• pp.919-933
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• 2021

We hypothesized that the unsaturated fatty acid palmitoleic acid (POA) could promote the expression of adipogenic/lipogenic genes in bovine skeletal muscle satellite cells (BSCs). The BSCs were cultured in a growth medium containing 10% fetal bovine serum. When the cells reached 80%-90% confluence, we used the differentiation medium with 5% horse serum for differentiation for 96 h. The differentiation medium contained 50 µM, 100 µM and 200 µM POA. Control BSC were cultured only in differentiation media. Compared with the control BSC, the POA BSC significantly up-regulated the expression of paired box 3 (Pax3) and paired box 7 (Pax7) and down-regulated myogenin gene expression (p < 0.01), which indicates a depression in muscle fiber development. However, all POA treatments up-regulated the expression of the adipocyte transcription factors peroxisome proliferator-activated receptor γ (PPARγ), CCAAT/enhancer-binding protein alpha and beta (C/EBP α and C/EBP β), and other genes (p < 0.01) and increased the expression of PAT-family proteins and the concentration of adiponectin in the media. These results indicate that POA can convert part of BSCs into adipocytes.

• Korean Journal of Pharmacognosy
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• v.21 no.3
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• pp.210-216
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• 1990

Effects of the protein fraction of Panax ginseng on chicken embryonic skeletal muscle cells cultured with a decfiient medium were studied. The protein fraction was further fractionated into four groups according to the molecular weight; larger than 10,000 dalton(fraction A), between 5,000 and 10,000 dalton(fraction B), between 1,000 and 5,000 dalton(fraction C), between 500 and 1,000 dalton(fraction D). According to the microscopic observation, all four protein fractions at the concentration of $10{\sim}100{\;}{\mu}g/ml$ showed the tendency to stimulate the growth and differentiation of the muscle cells. The activity of acetylcholinesterase in muscle cells was significantly elevated by the protein fraction A at the concentration of $100{\mu}{\;}g/ml$. Protein fractions B,C and D significantly enhanced the synthesis of RNA in the muscle cells. The synthesis of DNA in muscle cells was significantly enhanced by protein fractions A,B and C.

• Journal of Ginseng Research
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• v.43 no.3
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• pp.475-481
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• 2019

Background: The ginsenoside Rg1 has been shown to exert various pharmacological activities with health benefits. Previously, we have reported that Rg1 promoted myogenic differentiation and myotube growth in C2C12 myoblasts. In this study, the in vivo effect of Rg1 on fiber-type composition and oxidative metabolism in skeletal muscle was examined. Methods: To examine the effect of Rg1 on skeletal muscle, 3-month-old mice were treated with Rg1 for 5 weeks. To assess muscle strength, grip strength tests were performed, and the lower hind limb muscles were harvested, followed by various detailed analysis, such as histological staining, immunoblotting, immunostaining, and real-time quantitative reverse transcription polymerase chain reaction. In addition, to verify the in vivo data, primary myoblasts isolated from mice were treated with Rg1, and the Rg1 effect on myotube growth was examined by immunoblotting and immunostaining analysis. Results: Rg1 treatment increased the expression of myosin heavy chain isoforms characteristic for both oxidative and glycolytic muscle fibers; increased myofiber sizes were accompanied by enhanced muscle strength. Rg1 treatment also enhanced oxidative muscle metabolism with elevated oxidative phosphorylation proteins. Furthermore, Rg1-treated muscles exhibited increased levels of anabolic S6 kinase signaling. Conclusion: Rg1 improves muscle functionality via enhancing muscle gene expression and oxidative muscle metabolism in mice.

• Journal of Life Science
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• v.12 no.1
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• pp.55-60
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• 2002

The differentiation of skeletal muscle precursor cells in culture is marked by the transcriptional activation of muscle-specific genes and the morphological differentiation of myoblast into multinucleate myotube. In this study, we examined the effect of TSA (Trichostatin A) on WF-kB DNA binding activity and muscle cell fusion in the process of myogenesis. Under TSA treatment, C2C12 myoblast could not fuse to myotube and its NF-kB DNA binding activity was also blocked. To investigate whether these phenomenons were affected by TSA in direct or not, differentiation media (DM) used to differentiate cells without TSA was concentrated and added to C2C12 myoblast with TSA simultaneously. C2C12 myoblast was fused to myotube and NF-kB DNA binding activity was recovered. These results suggest that TSA affects on the differentiation of myoblast, perhaps through several factors, by inhibiting myoblst fusion and blocking NF-kB DNA binding activity.

• Molecules and Cells
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• v.27 no.4
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• pp.403-408
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• 2009

Skeletal muscle regeneration is a highly orchestrated process initiated by activation of adult muscle satellite cells. Upon muscle injury, the inflammatory process is always accompanied by muscle regeneration. Leukotriene $B_4$ is one of the essential inflammatory mediators. We isolated and cultured primary satellite cells. RT-PCR showed that myoblasts expressed mRNA for $LTB_4$ receptors BLT1 and BLT2, and $LTB_4$ promoted myoblast proliferation and fusion. Quantitative real-time PCR and immunoblotting showed that $LTB_4$ treatment expedited the expression process of differentiation markers MyoD and M-cadherin. U-75302, a specific BLT1 inhibitor, but not LY2552833, a specific BLT2 inhibitor, blocked proliferation and differentiation of myoblasts induced by $LTB_4$, which implies the involvement of the BLT1 pathway. Overall, the data suggest that $LTB_4$ contributes to muscle regeneration by accelerating proliferation and differentiation of satellite cells.

• Asian-Australasian Journal of Animal Sciences
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• v.31 no.8
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• pp.1088-1097
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• 2018

Objective: It is commonly accepted that adiponectin binds to its two receptors to regulate fatty acid metabolism in adipocytes. To better understand their functions in the regulation of intramuscular adipogenesis in goats, we cloned the three genes (adiponectin [AdipoQ], adiponectin receptor 1 [AdipoR1], and AdipoR2) encoding these proteins and detected their mRNA distribution in different tissues. We also determined the role of AdipoQ in the adipogenic differentiation of goat skeletal muscle satellite cells (SMSCs). Methods: SMSCs were isolated using 1 mg/mL Pronase E from the longissimus dorsi muscles of 3-day-old female Nanjiang brown goats. Adipogenic differentiation was induced in satellite cells by transferring the cells to Dulbecco's modified Eagle's medium supplemented with an isobutylmethylxanthine, dexamethasone and insulin cocktail. The pEGFP-N1-AD plasmid was transfected into SMSCs using Lipofectamine 2000. Expression of adiponectin in tissues and SMSCs was detected by quantitative polymerase chain reaction and immunocytochemical staining. Results: The three genes were predominantly expressed in adipose and skeletal muscle tissues. According to fluorescence and immunocytochemical analyses, adiponectin protein expression was only observed in the cytoplasm, suggesting that adiponectin is localized to the cytoplasm of goat SMSCs. In SMSCs overexpressing the AdipoQ gene, adiponectin promoted SMSC differentiation into adipocytes and significantly (p<0.05) up-regulated expression of AdipoR2, acetyl-CoA carboxylase, fatty-acid synthase, and sterol regulatory element-binding protein-1, though expression of CCAAT/enhancer-binding $protein-{\alpha}$, peroxisome proliferator-activated receptor ${\gamma}$, and AdipoR1 did not change significantly. Conclusion: Adiponectin induced SMSC differentiation into adipocytes, indicating that adiponectin may promote intramuscular adipogenesis in goat SMSC.

• BMB Reports
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• v.53 no.5
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• pp.278-283
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• 2020

Muscle fibers are generally formed as multinucleated fibers that are differentiated from myoblasts. Several reports have identified transcription factors and proteins involved in the process of muscle differentiation, but the roles of microRNAs (miRNAs) in myogenesis remain unclear. Here, comparative analysis of the miRNA expression profiles in mouse myoblasts and gastrocnemius (GA) muscle uncovered miR-3074-3p as a novel miRNA showing markedly reduced expression in fully differentiated adult skeletal muscle. Interestingly, elevating miR-3074-3p promoted myogenesis in C2C12 cells, primary myoblasts, and HSMMs, resulting in increased mRNA expression of myogenic makers such as Myog and MyHC. Using a target prediction program, we identified Caveolin-1 (Cav1) as a target mRNA of miR-3074-3p and verified that miR-3074-3p directly interacts with the 3' untranslated region (UTR) of Cav1 mRNA. Consistent with the findings in miR-3074-3p-overexpressing myoblasts, knockdown of Cav1 promoted myogenesis in C2C12 cells and HSMMs. Taken together, our results suggest that miR-3074-3p acts a positive regulator of myogenic differentiation by targeting Cav1.