• Molecules and Cells
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• 제28권6호
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• pp.589-593
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• 2009

In this study, the roles of the p38 MAPK, ERK1/2 and JNK signaling pathway in IGF-I-induced AR induction and activation were examined. C2C12 cells were treated with IGF-I in the absence or presence of various inhibitors of p38 MAPK (SB203580), ERK1/2 (PD98059), and JNK (SP600125). Inhibition of the MAPK pathway with SB203580, PD98059, or SP600125 significantly decreased IGF-I-induced AR phosphorylation and total AR protein expression. IGF-I-induced nuclear fraction of total AR and phosphorylated AR were significantly inhibited by SB203580, PD98059, or SP600125. Furthermore, IGF-I-induced AR mRNA and skeletal ${\alpha}-actin$ mRNA were blocked by those inhibitors in dose-dependent manner. Confocal images showed that IGF-I-induced AR nuclear translocation from cytosol was significantly blocked by SB203580, PD98059, or SP600125, suggesting that the MAPK pathway regulates IGF-I-induced AR nuclear localization in skeletal muscle cells. The present results suggest that the MAPK pathways are required for the ligand-independent activation of AR by IGF-I in C2C12 skeletal muscle cells.

• 한국수의병리학회:학술대회논문집
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• 한국수의병리학회 2002년도 추계학술대회초록집
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• pp.144-144
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• 2002

Muscular lesion was detected in a 23-month-old castrated bull encountered at Kyungsan slaughter house. The lesion appeared as fat intervening muscle fibers. The affected animal had no clinical signs. On microscopic examination, there was replacement of many muscle fibers by normal fat cells. Numerous fat cells were located between muscle fibers. Remaining skeletal muscle cells were in degenerative process, and thus abnormal skeletal muscle cells had loose fibers while normal had intact ones. The advent of inflammatory cells is not at the lesion, which is unique view in steatosis.

• 한국운동역학회지
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• 제16권3호
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• pp.75-83
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• 2006

The purpose of this study was to investigate steady-state force depression following active muscle shortening in human tibialis anterior muscle during voluntary contractions. Subjects (n = 7; age $24{\sim}39$ years; 7 males) performed isometric reference contractions and isometric-shortening-isometric contractions, using maximal voluntary effort. Force depression was assessed by comparing the steady-state isometric torque produced following active muscle shortening with the purely isometric reference torque obtained at the corresponding joint angle. In order to test for effects of the shortening conditions on the steady-state force depression, the speed of shortening were changed systematically in a random order but balanced design. Ankle dorsiflexion torque and joint angle were continuously measured using a dynamometer. During voluntary contractions, muscle activation of the tibialis anterior and the medical gastrocnemius was recorded using surface electromyography. Force depression during voluntary contractions, with a constant level of muscle activation, was 12 %, on average over all subjects. Force depression was independent of the speeds of shortening ($13.8{\pm}2.9%$, $10.3{\pm}2.6%$ for 15 and 45 deg/sec over 15 deg of shortening, respectively). The results of this study suggest that steady-state force depression is a basic property of voluntarily-contracting human skeletal muscle and has functional implication to human movements.

• 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.

• 대한본초학회지
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• 제27권2호
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• pp.53-59
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• 2012

Objectives : This study was undertaken to investigate the effects of the GGEx18 ethyl acetate fraction (EF) on lipid accumulation and gene expression of fatty acid-oxidizing enzymes using 3T3-L1 adipocytes, C2C12 skeletal muscle cells, and NMu2Li liver cells. Methods : PPAR${\alpha}$, AMPK and UCPs transactivation was examined in NMu2Li hepatocytes, C2C12 myocytes, and 3T3-L1 preadipocytes using transient transfection assays. Results : 1. Compared with control, EF significantly increased the mRNA expression of VLCAD in 3T3-L1 adipocytes. 2. Compared with control, EF (0.1 ${\mu}g/ml$) significantly inhibited lipid accumulation in 3T3-L1 adipocytes. 3. EF significantly increased the mRNA expression of AMPK${\alpha}$1, AMPK${\alpha}$2 and PPAR${\alpha}$ in C2C12 skeletal muscle cells compared with control. 4. EF significantly increased the mRNA expression of genes involved in fatty acid ${\beta}$-oxidation, such as thiolase, MCAD, and CPT-1 in C2C12 skeletal muscle cells compared with control. 5. EF significantly increased the mRNA expression of UCP2 involved in energy expenditure in C2C12 skeletal muscle cells compared with control. 6. Compared with control, EF (10 ${\mu}g/ml$) significantly inhibited lipid accumulation in C2C12 skeletal muscle cells. 7. EF (10 ${\mu}g/ml$) significantly increased the mRNA expression of ACOX, HD, VLCAD and MCAD in NMu2Li liver cells compared with control. Conclusions : These results suggest that EF may prevent obesity by increasing the mRNA expression of mitochondrial fatty acid ${\beta}$-oxidizing enzymes in 3T3-L1 adipocytes, by not only regulating the fatty acid oxidation through activation of AMPK and PPAR${\alpha}$, but also increasing the UCP2 mRNA expression in C2C12 skeletal muscle cells, and by stimulating the mRNA expression of fatty acid-oxidizing enzymes in NMu2Li liver cells.

• 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.

• The Korean Journal of Physiology and Pharmacology
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• 제21권6호
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• pp.651-656
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• 2017

Ursolic acid (UA) supplementation was previously shown to improve skeletal muscle function in resistance-trained men. This study aimed to determine, using the same experimental paradigm, whether UA also has beneficial effects on exercise-induced skeletal muscle damage markers including the levels of cortisol, B-type natriuretic peptide (BNP), myoglobin, creatine kinase (CK), creatine kinase-myocardial band (CK-MB), and lactate dehydrogenase (LDH) in resistance-trained men. Sixteen healthy participants were randomly assigned to resistance training (RT) or RT+UA groups (n=8 per group). Participants were trained according to the RT program (60~80% of 1 repetition, 6 times/week), and the UA group was additionally given UA supplementation (450 mg/day) for 8 weeks. Blood samples were obtained before and after intervention, and cortisol, BNP, myoglobin, CK, CK-MB, and LDH levels were analyzed. Subjects who underwent RT alone showed no significant change in body composition and markers of skeletal muscle damage, whereas RT+UA group showed slightly decreased body weight and body fat percentage and slightly increased lean body mass, but without statistical significance. In addition, UA supplementation significantly decreased the BNP, CK, CK-MB, and LDH levels (p<0.05). In conclusion, UA supplementation alleviates increased skeletal muscle damage markers after RT. This finding provides evidence for a potential new therapy for resistance-trained men.

• 한국동물학회지
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• 제36권3호
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• pp.319-328
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• 1993

칠성장어류를 제외한 모든 척추동물은 여러 유전자로 이루어진 젖산수소이탈효소를 지니고, 칠성장어류의 LDH는 cellulose acetate 및 starch gel 전기영동한 결과 단일 동위효소로 보고되어졌다. 그러나 본 실험에서 polyacrylamide gel 전기영동 방법에 의해서 칠성장어 골격근, 심장 및 신장의 LDH는 3개의 동위효소, 간의 LDH는 2개의 동위효소로 분리되었다. Polyacrylamide gel isoelectric focusing 방법으로는 골격근과 심장의 LDH는 4개의 동위효소, 간의 LDH는 2개의 동위효소로 분리되었고, 골격근의 LDH는 chromatofocusing한 결과 4개의 LDH 동위효소로 분리되었다. 칠성장어 골격근 LDH 동위효소들은 Sphadex G-200 gel filtration 결과 분자량이 140,000정도로 나타났다. 골격근, 심장 및 간조직 LDH 동위효소는 pyruvate에 의해 비슷한 정도로 저해되었으며 LDH $A_4$및 B$_4$동위효소의 중간정도의 저해를 보여주었다. 그리고 심장, 간 및 골격근 LDH 동위효소는 열에 안정하였다. 상기의 결과들로부터 칠성장어는 단일 동위효소가 아니라 동위효소들을 가지며 이 동위효소들을 이루는 각 하부단위체들의 구조는 유사하다고 사료된다.

• 생명과학회지
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• 제29권8호
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• pp.837-845
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• 2019

본 연구에서는 고지방식이로 유발된 비만 쥐의 골격근에서 유산소 운동과 레스베라트롤 투여가 미토콘드리아 생합성에 미치는 영향을 조사하였다. 4주령 C57BL/6의 수컷 쥐를 이용하여, 일반 식이 그룹(NC, n=10), 고지방식이 그룹(HR, n=10), 레스베라트롤 투여와 고지방식이 그룹(HRe, n=10), 유산소 운동 그룹(HE, n=10)으로 분류하였다. 유산소 운동은 16주 동안 40~60 min/day 동안 10-14m/min, 0% grade의 강도로 주당 4회 트레드밀 운동을 실시하였고, 레스베라트롤은 16주 동안 1일 1회, 주당 4회 체중 당 25 mg/kg을 투여하였다. COX-IV mRNA 발현은 NC와 HC 그룹 간에 유의한 차이가 있었으며(p<0.05), HE 그룹의 SIRT-3, $PGC-1{\alpha}$ 및 COX-IV mRNA 발현은 HC 및 HRe 그룹에 비해 유의하게 증가하였다(p<0.05). 또한, 오직 HE 그룹의 $PGC-1{\alpha}$ 및 COX-IV mRNA의 발현만이 HC 그룹에 비해 유의하게 증가하였다(p<0.05). 이상의 결과를 종합해보면, 고지방식이로 유발된 비만 쥐는 골격근에서 미토콘드리아 생합성 유전자 발현에 영향을 나타내지 않는 것으로 보인다. 하지만, 유산소 운동 훈련은 고지방식이로 유발된 비만 쥐의 골격근에서 미토콘드리아 생합성 유전자 발현을 증가시키는 것으로 나타났다. 이러한 연구 결과는 레스베라트롤 투여가 아닌 유산소 운동이 고지방식이로 유도된 쥐의 골격근에서 미토콘드리아 생합성에 긍정적인 영향을 미친다는 것을 시사한다.

• Animal Bioscience
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• 제35권10호
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• pp.1512-1523
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• 2022

Objective: The growth of pigs involves multiple regulatory mechanisms, and modern molecular breeding techniques can be used to understand the skeletal muscle growth and development to promote the selection process of pigs. This study aims to explore candidate lncRNAs and mRNAs related to skeletal muscle growth and development among Duroc pigs with different average daily gain (ADG). Methods: A total of 8 pigs were selected and divided into two groups: H group (high-ADG) and L group (low-ADG). And followed by whole transcriptome sequencing to identify differentially expressed (DE) lncRNAs and mRNAs. Results: In RNA-seq, 703 DE mRNAs (263 up-regulated and 440 down-regulated) and 74 DE lncRNAs (45 up-regulated and 29 down-regulated) were identified. In addition, 1,418 Transcription factors (TFs) were found. Compared with mRNAs, lncRNAs had fewer exons, shorter transcript length and open reading frame length. DE mRNAs and DE lncRNAs can form 417 lncRNA-mRNA pairs (antisense, cis and trans). DE mRNAs and target genes of lncRNAs were enriched in cellular processes, biological regulation, and regulation of biological processes. In addition, quantitative trait locus (QTL) analysis was used to detect the functions of DE mRNAs and lncRNAs, the most of DE mRNAs and target genes of lncRNAs were enriched in QTLs related to growth traits and skeletal muscle development. In single-nucleotide polymorphism/insertion-deletion (SNP/INDEL) analysis, 1,081,182 SNP and 131,721 INDEL were found, and transition was more than transversion. Over 60% of percentage were skipped exon events among alternative splicing events. Conclusion: The results showed that different ADG among Duroc pigs with the same diet maybe due to the DE mRNAs and DE lncRNAs related to skeletal muscle growth and development.