• 대한의생명과학회지
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• 제29권3호
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• pp.190-200
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• 2023

Skeletal muscle, essential for metabolism, thermoregulation, and immunity, undergoes myogenic differentiation that results in myotube formation. Trans-anethole (TA), the major constituent in essential oil produced by anise, star anise, and fennel, whose function in skeletal muscle has not yet been elucidated. Therefore, we investigated whether TA influenced muscle differentiation in mouse C2C12 myoblasts. Cells were induced to differentiate using a differentiation medium with or without TA (50 or 200 mg/mL) daily for 5 days. We measured myotube length and diameter after differentiation days 1, 3, and 5 and analyzed the expression of myogenic markers (myoblast determination protein 1, myogenin, myocyte enhancer factor 2, muscle creatine kinase, and myosin heavy chain) and atrophy-related genes (atrogin-1 and muscle ring finger-1 [MuRF-1]) using quantitative real-time PCR. Additionally, we observed the expression of total protein kinase B (Akt) and phosphorylated Akt (p-Akt) using western blotting. Our data showed that TA significantly induced the formation of smaller and thinner myotubes and reduced the myogenic factor expression. Furthermore, the atrogin-1 and MuRF-1 expression markedly increased by TA. Consistent with these findings, TA significantly decreased the expression of total Akt and p-Akt. Taken together, these results indicate that TA inhibits myogenic differentiation of C2C12 cells via reduction of both total Akt and p-Akt. Our findings may provide valuable insights into the impact of PAA on individuals at risk of muscle atrophy.

• Asian-Australasian Journal of Animal Sciences
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• 제32권8호
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• pp.1172-1185
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• 2019

Objective: Meat quality attributes in postmortem muscle tissues depend on skeletal muscle metabolites. The objective of this study was to determine the key metabolic compounds and pathways that are associated with postmortem aging and beef quality in Japanese Black cattle (JB; a Japanese Wagyu breed with highly marbled beef). Methods: Lean portions of Longissimus thoracis (LT: loin) muscle in 3 JB steers were collected at 0, 1, and 14 days after slaughter. The metabolomic profiles of the samples were analyzed by capillary electrophoresis time-of-flight mass spectrometry, followed by statistical and multivariate analyses with bioinformatics resources. Results: Among the total 171 annotated compounds, the contents of gluconic acid, gluconolactone, spermidine, and the nutritionally vital substances (choline, thiamine, and nicotinamide) were elevated through the course of postmortem aging. The contents of glycolytic compounds increased along with the generation of lactic acid as the beef aging progressed. Moreover, the contents of several dipeptides and 16 amino acids, including glutamate and aromatic and branched-chain amino acids, were elevated over time, suggesting postmortem protein degradation in the muscle. Adenosine triphosphate degradation also progressed, resulting in the generation of inosine, xanthine, and hypoxanthine via the temporal increase in inosine 5'-monophosphate. Cysteine-glutathione disulfide, thiamine, and choline increased over time during the postmortem muscle aging. In the Kyoto encyclopedia of genes and genomes database, a bioinformatics resource, the postmortem metabolomic changes in LT muscle were characterized as pathways mainly related to protein digestion, glycolysis, citric acid cycle, pyruvate metabolism, pentose phosphate metabolism, nicotinamide metabolism, glycerophospholipid metabolism, purine metabolism, and glutathione metabolism. Conclusion: The compounds accumulating in aged beef were shown to be nutritionally vital substances and flavor components, as well as potential useful biomarkers of aging. The present metabolomic data during postmortem aging contribute to further understanding of the beef quality of JB and other breeds.

• Molecules and Cells
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• 제40권2호
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• pp.123-132
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• 2017

Insulin signaling is coordinated by insulin receptor substrates (IRSs). Many insulin responses, especially for blood glucose metabolism, are mediated primarily through Irs-1 and Irs-2. Irs-1 knockout mice show growth retardation and insulin signaling defects, which can be compensated by other IRSs in vivo; however, the underlying mechanism is not clear. Here, we presented an Irs-1 truncated mutated mouse ($Irs-1^{-/-}$) with growth retardation and subcutaneous adipocyte atrophy. $Irs-1^{-/-}$ mice exhibited mild insulin resistance, as demonstrated by the insulin tolerance test. Phosphatidylinositol 3-kinase (PI3K) activity and phosphorylated Protein Kinase B (PKB/AKT) expression were elevated in liver, skeletal muscle, and subcutaneous adipocytes in Irs-1 deficiency. In addition, the expression of IRS-2 and its phosphorylated version were clearly elevated in liver and skeletal muscle. With miRNA microarray analysis, we found miR-33 was down-regulated in bone marrow stromal cells (BMSCs) of $Irs-1^{-/-}$ mice, while its target gene Irs-2 was up-regulated in vitro studies. In addition, miR-33 was down-regulated in the presence of Irs-1 and which was up-regulated in fasting status. What's more, miR-33 restored its expression in re-feeding status. Meanwhile, miR-33 levels decreased and Irs-2 levels increased in liver, skeletal muscle, and subcutaneous adipocytes of $Irs-1^{-/-}$ mice. In primary cultured liver cells transfected with an miR-33 inhibitor, the expression of IRS-2, PI3K, and phosphorylated-AKT (p-AKT) increased while the opposite results were observed in the presence of an miR-33 mimic. Therefore, decreased miR-33 levels can up-regulate IRS-2 expression, which appears to compensate for the defects of the insulin signaling pathway in Irs-1 deficient mice.

• 생명과학회지
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• 제25권10호
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• pp.1098-1102
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• 2015

본 연구에서는 C2C12 근육 세포의 분화 과정에 있어 IGF-I이 지방산의 수송을 담당하는 FABPpm mRNA 및 단백질 발현에 어떠한 영향을 미치는지에 대해 알아보았다. 그 결과 근육세포의 분화에 있어 FABPpm의 단백질과 mRNA 발현이 IGF-I에 의해 유의하게 조절되었음을 알 수 있었다. 이는 기존의 여러 연구의 결과인 IGF-I이 골격근에서 근육 관련 유전자들의 발현을 조절하여 근부피 유지 및 증대에 중심적인 역할 것뿐만 아니라, 지방산의 수송을 담당하는 FABPpm의 발현에도 영향을 미친다는 사실을 밝혔다는 것에 의의가 있다고 생각된다. 향후 골격근에서 IGF-I에 의한 FABPpm 발현 조절에 있어, 세포 내부에서의 신호전달 경로 및 상호작용 인자들에 관한 연구를 통해 지방 대사를 조절하는 기전에 관한 연구가 필요할 것으로 사료된다.

• 생명과학회지
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• 제24권12호
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• pp.1284-1290
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• 2014

본 연구에서는 C2C12 근육 세포에서 IGF-I이 지방산 저장과 사용에 영향을 미치는 FATP1의 mRNA 및 단백질 발현에 미치는 영향에 대해 알아보았다. 그 결과 IGF-I이 FATP1의 단백질과 mRNA 발현을 유의성 있게 조절하였음을 알 수 있었다. 이는 골격근에서 IGF-I이 근육 관련 유전자들의 발현을 조절하여 근부피 유지 및 증대에 중심적인 역할을 한다는 기존의 연구 패턴들에서 벗어나, IGF-I이 골격근 세포의 분화에 있어 지방산의 수송을 담당하는 FATP1의 발현에도 영향을 미친다는 사실을 증명하였다는데 의의가 있다고 사료된다. 향후 IGF-I에 의한 FATP1의 지방산 저장의 수준과 산화 과정에 있어 상호작용하는 기타 매개체들과의 관계에 대한 연구가 필요할 것으로 사료된다.

• 운동영양학회지
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• 제23권2호
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• pp.1-6
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• 2019

[Purpose] Strenuous exercise often induces skeletal muscle damage, which results in impaired performance. Sphingolipid metabolism contributes to various cellular processes, including apoptosis, stress response, and inflammation. However, the relationship between exercise-induced muscle damage and ceramide (a key component of sphingolipid metabolism), is rarely studied. The present study aimed to explore the regulatory role of sphingolipid metabolism in exercise-induced muscle damage. [Methods] Mice were subjected to strenuous exercise by treadmill running with gradual increase in intensity. The blood and gastrocnemius muscles (white and red portion) were collected immediately after and 24 h post exercise. For 3 days, imipramine was intraperitoneally injected 1 h prior to treadmill running. [Results] Interleukin 6 (IL-6) and serum creatine kinase (CK) levels were enhanced immediately after and 24 h post exercise (relative to those of resting), respectively. Acidic sphingomyelinase (A-SMase) protein expression in gastrocnemius muscles was significantly augmented by exercise, unlike, serine palmitoyltransferase-1 (SPT-1) and neutral sphingomyelinase (N-SMase) expressions. Furthermore, imipramine (a selective A-SMase inhibitor) treatment reduced the exercise-induced CK and IL-6 elevations, along with a decrease in cleaved caspase-3 (Cas-3) of gastrocnemius muscles. [Conclusion] We found the crucial role of A-SMase in exercise-induced muscle damage.

• Journal of Nutrition and Health
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• 제54권6호
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• pp.594-602
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• 2021

본 연구는 고지방식이로 유도한 비만 동물모델에서 아연의 식이를 통한 보충 급여가 혈당 조절과 골격 근육의 ZIP7의 작용에 미치는 영향에 대해 살펴보았다. 고지방식이를 공급한 HF군은 정상 대조군에 비하여 단위 체중당 골격 근육 무게가 유의하게 감소하였으며, 혈당은 유의적으로 증가하였다. 고지방식이와 함께 아연을 보충 공급한 HF+Zn군은 아연을 보충하지 않은 HF군과 비교하여, 공복 혈당과 경구 포도당 부하 후 혈당 증가 면적이 유의하게 감소하였다. 또한, HF+Zn군은 HF군에 비해 골격 근육의 ZIP7 단백질 수준이 유의하게 증가하였으며, AKT 활성과 GLUT4 단백질 수준도 유의하게 증가하는 것으로 나타났다. 이상의 결과를 종합해 볼 때, 아연 보충은 비만으로 인한 고혈당 증세를 완화하는 효과를 나타내며, 이는 골격 근육에서의 ZIP7 아연 수송체에 의한 당 대사 조절과 관련이 있을 것으로 생각된다.

• 생명과학회지
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• 제22권6호
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• pp.713-722
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• 2012

Landrace와 Berkshire의 longissimus dorsi muscle으로부터 단백질 발현양상의 차이를 보기 위하여 2-DE실험을 통하여 분석한 결과 Landrace 에서 특이적으로 발현 양이 증가한 단백질들은 serum albumin precursor, troponin T (TnT; slow skeletal muscle), myoglobin였다. Berkshire에서 특이적으로 발현 양이 증가한 단백질들은 heat shock 27 kDa protein 1, troponin T (fast skeletal muscle), muscle creatine kinase, phosphoglucomutase 1, triosephosphate isomerase (Tpi 1), adenylate kinase isoenzyme 1 (AK1)였다. Landrace의 longissimus dorsi muscle에서는 slow skeletal muscle과 연관된 단백질들이 발현된 반면에 Berkshire에서는 fast skeletal muscle, 물질대사경로, 에너지 생산과 관련된 단백질들이 발현되었다. Berkshire를 이용하여 성장단계별로 단백질 발현을 분석해 본 결과 growing Berkshire에서 발현이 증가한 단백질은 aldehyde dehydrogenase 1 family, member L1 (ALDHL1)와 muscle creatine kinase이고 finishing Berkshire에서 발현이 증가한 단백질은 heat shock 27 kDa protein 1, TnT (slow skeletal muscle), TnT (fast skeletal muscle), serum albumin precursor, PGM 1, AK 1, Tpi 1였다. 이 결과는 Finishing Berkshire의 등심에서는 growing Berkshire에 비교하여 골격근육, 에너지물질대사, 세포골격 등이 보다 활성화된 것으로 사료된다.

• Clinical Nutrition Research
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• 제5권2호
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• pp.126-136
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• 2016

Due to poor nutrition and abnormal energy metabolism, cancer patients typically experience the loss of muscle mass. Although the diabetic conditions or dyslipidemia have been reported as a causal link of cancer but the consequence of such conditions in relation to gain or loss of skeletal muscle mass in cancer patients has not been well documented. The purpose of this study was to investigate the relationship of lean body mass and systemic parameters related to lipid metabolism in non-diabetic cancer patients using data from the Korean National Health and Nutrition Examination Survey (KNHANES) 2008-2011. As results the level of serum total cholesterol (total-C) was negatively associated with both total lean body mass and appendicular lean body mass in cancer patients after adjustment for sex, physical activity, energy intake and comorbidity. The associations between consumption of dietary factors (energy, carbohydrate, protein and fat) and lean body mass were disappeared after adjusting comorbidities of cancer patients. Multivariate-adjusted linear regression analysis by quartiles of serum total-C showed that higher quartile group of total-C had significantly lower percent of lean body mass than reference group in cancer patients. The data indicate that serum lipid status can be the potential estimate of loss of skeletal muscle mass in cancer patients and be referenced in nutrition care of cancer patients under the onset of cachexia or parenteral/enteral nutrition. This data need to be confirmed with large pool of subjects and should be specified by stage of cancer or the site of cancer in future studies.

• Journal of Nutrition and Health
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• 제28권5호
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• pp.426-434
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• 1995

The purpose of this study were to investigate the effect of fasting and vitamin B6 repletion on tissue concentration of pyridoxal 5-phosphate and urinary excreteion of 4-pyridoxic acid in vitamin B6 deficient rats. Sixty six rats(6 per group) were fed either a vitamin B6 deficient diet (-B6) or a control diet (+B6) for 6 weeks and then rats were repleted with +B6 diet for 2 weeks. Rats were fasted for 1 and 3 days and for 3 days after repletion. Pyridoxal 5-phosphate (PLP) concentration in plasma, liver, skeletal muscle, and heart muscle and urinary 4-pyridoxic acid (4-PA) excretion were compared. Fasting resulted in a significant increase in PLP concentration in the plasma, liver and heart muscle of rats fed the -B6 diet. Skeletal muscle PLP concentration was significantly decreased in +B6 rats but not in -B6 rats. Following vitamin B6 repletion, PLP concentration in the plasma, liver and heart muscle in previously -B6 rats was similar to the respective concentration in +B6 rats while PLP concentration in the skeletal muscle of previously -B6 rats increased, but it was not reached to that of +B6 rats. At day 1 and 2 of the fast, urinary 4-PT excretion increased in both +B6 and -B6 rats although there was no supply of vitamin B6 due to fasting. These results suggest that vitami B6 is redistributed as PLP when there is a caloric deficit and PLP is supplied by an endogenous source, possibly PLP bound to skeletal muscle glycogen phosphorylase.