• Title/Summary/Keyword: Skeletal muscle

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Trans-anethole Suppresses C2C12 Myoblast Differentiation

  • Mi-Ran Lee
    • Biomedical Science Letters
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    • v.29 no.3
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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.

Developmental Proteomic Profiling of Porcine Skeletal Muscle during Postnatal Development

  • Kim, Nam-Kuk;Lim, Jong-Hyun;Song, Min-Jin;Kim, Oun-Hyun;Park, Beom-Young;Kim, Myung-Jick;Hwang, In-Ho;Lee, Chang-Soo
    • Asian-Australasian Journal of Animal Sciences
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    • v.20 no.10
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    • pp.1612-1617
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    • 2007
  • In this study, we have compared the skeletal muscle proteome at various stages of porcine postnatal development. Korean native pigs were divided into five postnatal stages of 30, 70, 130, 170 and 300 d and their loin muscles were analyzed for muscle proteome by using two-dimensional electrophoresis and mass spectrometry. We found 5 proteins showing a consistent pattern during skeletal muscle growth. Four proteins were identified as myosin light chain 1 slow-twitch (MLC1sa) isoform, troponin T, triosephosphate isomerase (TIP) and DJ-1 protein. The remaining protein was not identified. Two muscle fiber proteins of MLC1sa isoform and troponin T showed a high expression level at an early postnatal stage and then their levels were decreased markedly during growth stages. On the other hand, the expression of TIP and DJ-1 protein, which are well known as catalysis enzyme and antioxidant-related protein, respectively, were linearly increased during growth stages. Thus, the stage-related muscle proteins may be useful as parameters for understanding the developmental characteristics of biochemical and physiological properties in Korean native pig skeletal muscle.

Development of a Digital Textbook on 'Structure and Contraction Mechanism of Skeletal Muscle' with the Learning Model for Biomimicry-Based Convergence (생체모방 기반 융합 학습 모델을 적용한 '골격근의 구조와 수축'에 대한 디지털 교재 개발)

  • Kim, Soo-Youn;Kwon, Yong-Ju
    • Journal of Science Education
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    • v.42 no.2
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    • pp.95-105
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    • 2018
  • The purpose of this study was to develop a digital textbook on 'structure and contraction mechanism of skeletal muscle' with the learning model for biomimicry-based convergence. The unit of 'structure and contraction mechanism of skeletal muscle' is a part of Life Science I in high school. The convergence learning model was designed with three phases of biomimicry-based convergence (Exploration-Design-Implementation) including 3D modeling & printing. The developed digital textbook was composed of 8 sessions which contains the following learning contents : Exploration of skeletal muscle, creative designing of skeletal muscle using sketch application and 3D modeling, convergent implementing of the designed using 3D printing, exploration of muscle contraction, creative designing of muscle contraction using sketch application and 3D modeling, and convergent implementing of the designed using 3D printing. Each session is also involved in the contents of gallery widgets, media widgets, keynote widgets, sketch widgets, the cloud, polling widgets, and review widgets for interactive and mobile learning. After administering the developed digital textbook to 20 high school students, it was shown a positive effectiveness on life science learning for high school students. Moreover, the digital textbook was evaluated as to promote student's abilities on creative designs and implementation related to biomimicry-based convergence. The digital textbook was also shown a favorable response on students' interest and self-directed learning on life science.

Effects of 17-DMAG Administration on Autophagy Flux in Mouse Skeletal Muscle (17-DMAG이 마우스 골격근에서 autophagy flux에 미치는 영향)

  • Ju, Jeong-sun;Lee, Yoo-Hyun
    • Journal of Life Science
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    • v.26 no.4
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    • pp.387-397
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    • 2016
  • The purpose of this study was to determine if heat shock proteins are involved in autophagy in skeletal muscle. We used the autophagy flux strategy, which is an LC3 II/p62 turnover assay conducted with and without an autophagy inhibitor, to determine whether 17-DMAG (an Hsp90 inhibitor/Hsp72 activator) stimulates autophagy in skeletal muscle. We treated C2C12 cells with 17-DMAG (500 nM) for 24 hr with and without the autophagy inhibitor (Bafilomycin A1, 200 ng/ml), and we injected C57BL/6 mice i.p. with 17-DMAG (10 mg/kg) daily for 7 days with and without colchicine as an autophagy inhibitor (0.4 mg/kg/day, administered on the last 2 days). C2C12 myotubes and tibialis anterior muscles were harvested for analysis of mTOR-dependent autophagy signaling pathway proteins and autophagic marker proteins (p62 and LC3 II) by Western blot analysis. The blots showed that 17-DMAG upregulated hsp72 and decreased Akt protein levels and S6 phosphorylation in C2C12 cells. However, an in vitro autophagic flux assay demonstrated that 17-DMAG did not increase LC3 II and p62 protein concentrations to a greater extent than Bafilomycin A1 treatment alone. Similarly, 17-DMAG increased Hsp72 protein levels and decreased the expression of Akt and the phosphorylation of S6 in mouse skeletal muscle. However, unlike the response seen in C2C12 myotubes, the p62 protein levels were significantly decreased in 17-DMAG-treated mouse skeletal muscle (~50%; p<0.05). The LC3 II protein levels in 17-DMAG-treated mice were increased ~2-fold more when degradation was inhibited by colchicine (p<0.01). This suggests that 17-DMAG stimulates basal autophagy in skeletal muscle but is not found in C2C12 myotubes.

Insulin-like Growth Factor-I Induces Plectin and MACF1 Expression in C2C12 Myotubes (C2C12 myotube에서 insulin-like growth factor-I이 plectin과 MACF1 발현에 미치는 영향)

  • Kim, Hye Jin;Hwang, Ji Sun;Kwak, Yi-Sub;Lee, Won Jun
    • Journal of Life Science
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    • v.22 no.12
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    • pp.1651-1657
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    • 2012
  • Plectin and microtubule actin cross-linking factor 1 (MACF1) are architectural proteins that contribute to the function of skeletal muscle as generators of mechanical force. However, the influence of insulin- like growth factor-I (IGF-I), a master regulator of skeletal muscle cells, on plectin and MACF1 in skeletal muscle cells has not been demonstrated. The effect of IGF-I on plectin and MACF1 gene expression was investigated by treating differentiated C2C12 murine skeletal muscle cells with 20 ng/ml of IGF-I at different time points. The IGF-I treatment increased plectin protein expression in a dose-dependent manner. The mRNA level of plectin was measured by real-time quantitative PCR to determine if plectin induction was regulated pretranslationally. IGF-I treatment resulted in a very rapid induction of plectin mRNA transcript in C2C12 myotubes. Plectin mRNA increased by 140 and 180% after 24 and 48 hours of IGF-I treatment, respectively, and returned to the control level after 72 hours of IGF-I treatment. MACF1 mRNA increased 86 and 90% after 24 and 48 hours of IGF-I treat-ment, respectively, and returned to the control level after 72 hours of IGF-I treatment. These results suggested that the plectin gene is regulated pretranslationally by IGF-I in skeletal muscle cells. In conclusion, IGF-I induces a rapid transcriptional modification of the plectin and MACF1 genes in C2C12 skeletal muscle cells and has modulating effects on a cytolinker protein as well as on contractile proteins.

Comprehensive Relevance of AMPK in Adaptive Responses of Physical Exercise, Skeletal Muscle and Neuromuscular Disorders

  • Lee, Jun-Ho
    • Journal of the Korean Society of Physical Medicine
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    • v.13 no.3
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    • pp.141-150
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    • 2018
  • PURPOSE: This study was conducted to understand the adaptive responses of different modes of physical exercises utilizing skeletal muscle and the comprehensive relevance of AMPK signaling that can be activated by physical exercise as a potential molecular target in human health problems such as neuromuscular disorders (NMDs). METHODS: Most of the contents in this review article are based on recent publications concerning the main topics of interest. The reference literatures cited were obtained by basic searches of overseas academic databases such as PubMed and ScienceDirect using EndNote X7.8. RESULTS: The phenotypic adaptive responses of skeletal muscle during endurance- and resistance-based exercise training (ET and RT respectively) appear to be distinct. To explain the adaptive responses in each single mode of exercises (ET, RT) along with combined exercise training (CT), AMPK signaling is proposed as an important molecular link among those differential modes of exercise and a promising molecular target of NMDs. CONCLUSION: Based on the available evidence, intracellular AMPK signaling activated by diverse stimuli including physical exercise can be a potential and promising therapeutic target for the prevention, amelioration or cure of various human health problems including NMDs and may also be beneficial for physical rehabilitation and emergency situations that may elicit acute metabolic stresses.

Effect of Mitochondrial Inhibitor on Lactate Dehydrogenase of Mesocricetus auratus and Bos taurus coreanae (햄스터와 소의 젖산탈수소효소에 대한 미토콘드리아 inhibitor의 영향)

  • Cho Sung Kyu;Lee Sang Hak;Yum Jung Joo
    • Journal of Life Science
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    • v.15 no.1 s.68
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    • pp.100-105
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    • 2005
  • The lactate dehydrogenase (EC 1.1.1.27, LDH) inhibitors were isolated from the LDH-free crude mitochondrial fraction of skeletal muscle in Syrian hamster (Mesocricetus auratus) and Korean native cattle (Bos taurus coreanae). The LDH inhibitor in skeletal muscle of M. auratus was successfully isolated by the treatment with 175 mM NaCl and ultrasonic. The LDH inhibitor in skeletal muscle of B. taurus coreanae was highly stable to heat and LDH fu isozyme was largely inhibited by the LDH inhibitor. The molecular weight of inhibitor was 22 kDa. Inhibitor played an important role in the binding of LDH with the mitochondria in tissues of skeletal muscle, kidney and liver except heart.

Bovine abortion associated with neospora in Korea (Neospora에 의한 소 유산 발생)

  • Kim, Dae-yong;Hwang, Woo-suk;Kim, Jae-hoon;Hur, Kwon;Hwang, Ui-Gyeong;Lee, Byeong-chun;Jean, Young-hwa;Rhee, Jae-chin;Choi, Sang-ho
    • Korean Journal of Veterinary Research
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    • v.37 no.3
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    • pp.607-612
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    • 1997
  • A case of neosporosis is described in a 6-month-old aborted bovine fetus. Grossly, numerous, well-demarcated, 2-3mm, yellowish white foci were scattered in the heart and skeletal muscle. Histopathologic changes were confined to the brain, heart, and skeletal muscle. Multifocal areas of necrotizing encephalitis were observed in the cerebrum as well as cerebellum. Severe multifocal to coalescing nonsuppurative inflammation was observed in the myocardium and skeletal muscle. The tachyzoites of Neospora caninum were demonstrated in the brain, myocardium and skeletal muscle with immunohistochemical method using Neospora caninum-specific antibody. Based on the histopathology and immunohistochemistry, this case was diagnosed as neosporosis in aborted Korean cattle. This is believed to be the first reported case of bovine neosporosis in Korea.

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Metastasis to the Skeletal Muscle from a Malignant Phyllodes Tumor of the Breast: A Case Report (골격근육에 전이된 악성 유방 엽상종양의 영상소견: 증례 보고)

  • Kim, Dae-Jung;Yoon, Choon-Sik;Koo, Ja-Seung;Chung, Woo-Hee;Haam, Seok-Jin;Lee, Doo-Yun;Kim, Sung-Jun
    • Investigative Magnetic Resonance Imaging
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    • v.13 no.1
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    • pp.101-105
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    • 2009
  • We report radiological findings of ultrasonography (US), 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) computed tomography (CT), and magnetic resonance (MR) imaging for a rare case of skeletal muscle metastasis from an underlying known malignant phyllodes tumor. To our knowledge, there has been no previous published report of imaging findings of skeletal muscle metastasis from a sarcoma such as malignant phyllodes tumor.

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Factors Influencing Age-Related Loss of Skeletal Muscle Mass in Young Korean Men

  • Jongseok Hwang;Jeong-Kun Lee
    • Journal of the Korean Society of Physical Medicine
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    • v.18 no.4
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    • pp.67-75
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    • 2023
  • PURPOSE: This study aimed to identify the clinical factors that contribute to age-related loss of skeletal muscle mass (ALSMM) among young Korean male adults. METHODS: This was a cross-sectional study involving 955 men aged between 20-29 years. They underwent screening to assess the ALSMM. The study examined a variety of factors, including age, height, weight, body mass index (BMI), waist circumference (WC), skeletal muscle mass index (SMI), lifestyle-related habits such as smoking and drinking status, systolic and diastolic blood pressure (SBP/DBP), fasting blood glucose (FBG) levels, as well as the serum triglyceride and total cholesterol (TC) levels. RESULTS: The variables that displayed significant associations with ALSMM were height, weight, BMI, WC, SMI, FBG, TC, DBP, and alcohol consumption (p < .05). Serum triglyceride levels, SBP, and smoking status did not exhibit statistical significance (p > .05). CONCLUSION: The study identified the contributing factors associated with the ALSMM in community-dwelling young adult males. These findings would enrich the current body of literature on ALSMM and provide potential risk factors associated with its development in young Korean males.