• Asian-Australasian Journal of Animal Sciences
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• 제19권10호
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• pp.1508-1513
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• 2006

Myostatin (MSTN) and insulin-like growth factors (IGFs) are a known inhibitor and stimulators of proliferation and differentiation of muscle cells, respectively. The present study was performed to investigate the relationship of MSTN-induced growth inhibition to expression of the IGF system components and myogenin, a muscle cell-specific transcription factor, in rat L6 myoblasts. The L6 cells transfected with a green fluorescent protein-MSTN plasmid expression construct had a 47% less cell number than mock-transfected cells after 3-d serum-free culture, accompanied by delayed differentiation which was suggested by inhibited aggregation of cells. Moreover, cells transfected with the expression construct had decreased expression of IGF-II and myogenin genes, but not IGF-I or its receptor genes, as examined by reverse transcription-polymerase chain reaction. The reduced mitosis of the L6 cells transfected with the MSTN-expression construct increased following an addition of either IGF-I or IGF-II to the culture medium, but not to the level of mock-transfected cells. By contrast, myogenin gene expression in these cells increased after the addition of either IGF to the level of mock-transfected cells. Collectively, these results suggest that the inhibitory effect of MSTN on L6 cell proliferation and differentiation is likely to be partly mediated by serially suppressed expression of IGF-II and myogenin genes, not IGF-I gene.

• Asian-Australasian Journal of Animal Sciences
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• 제20권3호
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• pp.432-439
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• 2007

Thiazolidinediones (TZDs) act as potent activators of the adipose differentiation program in established preadipose cell lines. TZD's have also been investigated in diabetic patients and reported to act as PPAR-${\gamma}$ ligands. In this report, the effects of TZDs on the differentiation pathway of myoblasts have been investigated. C2C12 mouse myoblasts were grown in Dulbecco's Modified Eagles medium for 4-5 days until they reached almost 100% confluency. Post-confluent cells (day 0) were further exposed to adipogenic induction medium along with TZDs for 48 hours. Thereafter, cells were exposed only to TZDs every 48 h until day 10. The control was provided with differentiation medium without any treatment. Alterations in the cells during the differentiation programme were analyzed on the basis of fusion index, oil-red-o staining, adipocyte index, adipocyte stain uptake measurement, immuno-histochemistry and western blotting. Exposure of C2C12 mouse myoblasts to TZDs prevented the expression of myosin heavy chain with parallel increase in the expression of C/EBP-${\alpha}$ and PPAR-${\gamma}$ and acquisition of adipocyte morphology, thus abolishing the formation of multinucleated myotubes. TZDs exert their adipogenic effects only in non-terminally differentiated myoblasts; myotubes were insensitive to the compound. Continuous exposure (at least 4-5 doses) to inducers after the growth arrest was essential to provide a sustained environment to the cells converting to fully matured adipoctyes. The results indicate that TZDs specifically converted the differentiation pathway of myoblasts into that of adipoblasts.

• Preventive Nutrition and Food Science
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• 제19권3호
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• pp.187-193
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• 2014

This is an Open Access article distributed under the terms of the Creative Commons Attribution For decades, Spergularia marina, a local food that is popular in South Korea, has been regarded as a nutritious source of amino acids, vitamins, and minerals. While several halophytes are reported to possess distinct bioactivities, S. marina has yet to be promoted as a natural source of bioactives. In this study, the effects of S. marina on the adipogenic differentiation of 3T3-L1 fibroblasts and the osteoblastic differentiation of MC3T3-E1 pre-osteoblasts and C2C12 myoblast cells were evaluated. The anti-adipogenic effect of S. marina was assessed by measuring lipid accumulation and adipogenic differentiation marker expression. S. marina treatment significantly reduced lipid accumulation and notably decreased the gene levels of peroxisome proliferator-activated receptor ${\gamma}$, CCAAT/enhancer-binding protein ${\alpha}$, and sterol regulatory element binding protein 1c. In addition, S. marina enhanced osteoblast differentiation, as indicated by increased alkaline phosphatase activity and increased levels of osteoblastogenesis indicators, namely bone morphogenetic protein-2, osteocalcin, and type I collagen. In conclusion, S. marina could be a source of functional food ingredients that improve osteoporosis and obesity. Further studies, including activity-based fractionation, will elucidate the mechanism of action and active ingredients of S. marina, which would provide researchers with a better understanding of the nutraceutical and therapeutic applications of S. marina.

• 대한본초학회지
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• 제34권6호
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• pp.99-107
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• 2019

Objective : The present study was conducted to investigate the effects of Chaenomelis Fructus (CF) on the regulation of biogenesis in C2C12 mouse skeletal muscle cells. Methods : C2C12 myoblasts were differentiated into myotubes in 2% horse serum-containing medium for 5 days, and then treated with CF extract at different concentrations for 48 hr. The expression of muscle differentiation markers, myogenin and myosin heavy chain (MHC) and mitochondrial biogenesis-regulating factors, peroxisome proliferator-activated receptor gamma coactivator 1alpha (PGC1α), sirtuin1 (Sirt1), nuclear respiratory factor1 (NRF1) and transcription factor A, mitochondrial (TFAM), and the phosphorylation of AMP-activated protein kinase (AMPK) and acetyl-CoA carboxylase (ACC) were determined in C2C12 myotubes by reverse transcriptase (RT)-polymerase chain reaction (RT-PCR) and western blot, respectively. The cellular glucose levels and total ATP contents were measured by cellular glucose uptake and ATP assays, respectively. Results : Treatment with CF extract (0.01, 0.02, and 0.05 mg/㎖) significantly increased the expression of MHC protein in C2C12 myotubes compared with non-treated cells. CF extract significantly increased the expression of PGC1α and TFAM in the myotubes. Also, CF extract significantly increased glucose uptake levels and ATP contents in the myotubes. Conclusion : CF extract can stimulate C2C12 myoblasts differentiation into myotubes and increase energy production through upregulation of the expression of mitochondrial biogenetic factors in C2C12 mouse skeletal muscle cell. This suggests that CF can help to improve skeletal muscle function with stimulation of the energy metabolism.

• 생명과학회지
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• 제33권1호
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• pp.64-72
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• 2023

심장 발생과정에 관여하는 주요 전사인자들의 기능에 대한 규명 등의 발전에도 불구하고 줄기 세포에서 매우 효율적인 심근 세포로의 분화를 촉진하는 새로운 생체 활성 분자를 찾는 것이 여전히 필요하다. 마우스배아줄기세포(mESC) 유래 심근세포의 Illumina 발현 마이크로어레이 데이터를 분석하였다. 미분화 mESCs와 비교하여 mESC 유래 심근세포에서 4배 이상 유전자 발현이 증가한 276개 유전자가 스크리닝되었다. Secreted phosphoprotein 2 (Spp2)는 후보물질 중 하나이며 bone morphogenetic protein 2 (BMP2)에 대한 슈도수용체로서 BMP2 신호 전달을 억제하는 것으로 알려져 있다. 그러나 심근 형성과의 연관성은 알려진 바 없다. 우리는 mESC 세포주인 TC-1/Kh2와 E14를 이용하여 기능성 심근세포로 분화하는 동안 Spp2 발현이 증가함을 검증하였다. 흥미롭게도, Spp2 분비는 배아체(embryoid body, EBs) 형성 후 3일차에 일시적으로 증가했는데, 이는 Spp2의 분비가 ESCs의 심근세포로의 분화에 관여함을 시사한다. Spp2의 기능을 분석하기 위해, 우리는 BMP2를 처리하면 분화 경로를 근모세포에서 골모세포로 전환되는 특성을 가진 C2C12 마우스 근모세포 세포주를 사용하여 실험을 수행하였다. mESCs의 분화와 유사하게, Spp2의 전사는 C2C12 근모세포가 근관으로 분화됨에 따라 증가하였다. 특히, 분화 초기 단계에서 Spp2의 세포외 분비가 극적으로 증가하였다. 또한, Spp2-Flag 재조합 단백질로 처리하면 C2C12 근모세포의 근관으로의 분화가 촉진되었다. 종합하면, ESCs를 심근 세포로 분화시키는 새로운 생체 활성 단백질로 Spp2를 제안한다. 이것은 심근형성의 분자 경로를 이해하고 허혈성 심장질환에 대한 줄기세포 요법의 실험적 또는 임상적 발전을 촉진하는 역할을 할 것으로 기대한다.

• Animal cells and systems
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• 제1권1호
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• pp.93-98
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• 1997

The present study investigated the cellular localization of a-subunit of Gq (Gaq) protein in developing L8E63, rat skeletal muscle cell line. The colocalization of Gaq with actin cytoskeleton was demonstrated by double-labeling experiments. In mononucleated myoblasts, the immuno-fluorescence staining pattern of Gaq was almost identical with that of F-actin visualized with rhodamine-conjugated phalloidin. However, this colocalization of Gaq with cytoskeleton was not maintained in multinucleated myotubes. The staining pattern of Gaq in myotubes did not match with any specific subcellular structure, but appeared as a uniformly distributed diffuse staining throughout the whole cell surface. Interestingly, change in the expression level of Gaq was not detected during myoblast differentiation, suggesting that actin-associated Gaq protein might dissociate from the cytoskeleton as cells differentiate. Immunocytochemical experiments using specific antibodies directed against several G proteins indicated that the subcellular localizations of Gai1, Gai2, Gai3, and Gao were different from those obtained with Gaq.

• 한국동물학회지
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• 제34권4호
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• pp.610-617
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• 1991

계배 근원세포의 분화 및 증식에 미치는 F3+의 영향을 조사하였다. 철이 없는 배양액은 근원 세포의 분화와 증식을 억제하는 것으로 나타났으며 , 따라서 근원세포의 분화에 철과 transferrin (Tf)은 필수적이다. 또한, 철 대신에 Co2+가 부착된 Tf가 첨가된 배양액에서도 근세포의 분화가 정상적으로 일어나는 것으로 나타났다. Lysosomotrophic amine(chloroquine, $\mu$M 수준;ammonium chloride, mM 수준)은 근세포의 분화와 증식을 억제시켰으며 , 근세포 분화의 철에 대한 의존성은 분화됨에 따라 둔화되었다. 세포내로의 T니 수송량은 MEM과 8102배양액에서 비슷하였고, 근세포가 분화됨에 따라 감소하였다. Lysosomotrophic azine은 최소한 3시간이 내에서는 세포내로 수송되는 Tf의 양에 영향을 미치지 못하였다.

• 한국동물학회지
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• 제38권1호
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• pp.49-54
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• 1995

본 연구자들은 근원세포를 면역시켜 얻은 hybidoma들을 검색하여. 계배 근원세포의 분화와 관련된 단백질을 인지하여 분화를 억제하는 대과가 있는 monoclonal antibody 3H35를 선별하여 그 항원을 확인한 바 있다(Kim et af.. (1992), Korean J. Zool 35 29-36) 본 연구에서는 λZAP에 cloning된 chicken muscle CDNA library들을 lacZ fusion protein으로 발현시켜 항체 3H35로 검색하여 그 유전자를 찾아내었다. 선별한 CDNA clone 중 C59의 삽입 절편은 1.6 kb이었고, 발현시킨 facE fusion protein 은 60 kDa로, f-galactosidase에 대한 항체에 반응하며 3H35와도 반응함을 immunoaffinitv adsorbant와 immunoblot으로 확인하였다 Clone C59의 삽입 절편의 염기서열을 분석한 결과, 실제 유전자는 1.6 kb 이상이며, 알려진 어느 다른 유전자와도 관련이 없는 새로운 근특이 유전자로 판단되었다. 아미노산으로 전환시켰을 때 31개의 특이한 서열이 7차례 반복된 부분이 나타났으며 이 서열의 23개가 일정하게 보존되어있고 나머지 서열의 아미노산의 polarity도 매우 유사하게 효존되어있다. 이들의 보존성이 극히 높은 것으로 보아 독특한 기능을 수행하는 domain으로 추정된다.

• 약학회지
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• 제31권5호
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• pp.296-301
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• 1987

Polyamines of Korean red ginseng were extracted with 5% trichloroacetic acid and purified by ion exchange chromatography using Dowex-50Wx8 resin. Four spots having R$_f$ values of 0.19, 0.28, 0.35, and 0.45 were detected. It was observed under microscopy that those polyamines stimulated the growth and differentiation of chicken embryonic muscle cell. The development of muscle cells from the stage of myoblast to that of myotube was found to be enhanced by those polyamines. It was also observed that those polyamines most likely lengthened, the life-span of the cultured chicken embryonic skeletal muscle cells.

• 한국동물학회지
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• 제30권2호
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• pp.177-192
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• 1987

온열처리가 근세포의 분화에 어떤 영향을 미치는 지를 알아보기 위하여 배양한 근세포에 여러가지 온열처리를 한 다음, 단백질 합성, 세포증식, 융합지수, creatine kinase(CK)의 활성 및 cholesterol 함량의 변화를 조사하였다. 배양한지 24시간지나 45$^{\circ}C$에서 1 hr의 온열처리를 하면 근세포의 융합과 CK 활성이 지연되었으며, 55시간지나 같은 온열처리를 하면 세포막내(세포내 양의 95% 이상)의 chloesterol 양이 일시적으로 증가함과 아울러 세포융합이 지연되었다. 그러나 세포증식은 대조군과 뚜렷한 차이가 없었다. 이상과 같은 실험 결과로부터 온열처리가 분화에 미치는 영향은 온열처리를 받게되는 근원세포의 분화정도에 따라 차이가 있으며 온열처리에 따른 chloesterol 양의 일시적인 증가가 근세포 융합에 영향을 미칠 수 있다는 가능성이 제시되었다. 한편, 근세포는 온열처리를 받으면 평소의 단백질 합성 수준이 떨어짐과 더불어 heat shock protein(HSP)합성이 증대 내지는 유도 되었으며 HSP 합성의 유도는 actinomycin D의 처리로 억제되었다. 또한 온열처리로 근세포는 열내성을 얻어 세포융하과 CK 활성은 동일한 온열처리를 4시간 간격으로 두번 주어도 한번 주었을 경우와 차이가 없었으며 두번째 온열처리에 의해서는 새로운 HSP 합성이 유도되지도 않았다.