C2C12 CELLS - BIOPHYSICAL, BIOCHEMICAL, AND IMMUNOCYTOCHEMICAL PROPERTIES
C2C12 CELLS - BIOPHYSICAL, BIOCHEMICAL, AND IMMUNOCYTOCHEMICAL PROPERTIES
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DOI：
10.1152/ajpcell.1994.266.6.c1795
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发表时间：
1994-06-01
影响因子：
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通讯作者：
MALOUF, NN
中科院分区：
文献类型：
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作者：
MCMAHON, DK;ANDERSON, PAW;MALOUF, NN
我们研究了C2 C12，小鼠骨骼肌细胞系（美国典型培养物保藏中心）的肌原纤维的生化，结构和生物物理特性，以评估是否可以在C2 C12肌管中测量力的发展和肌丝对钙的敏感性，以及心肌收缩蛋白，肌钙蛋白T，是否表达并纳入C2 C12肌原纤维。当成肌细胞融合并分化为肌管时，肌丝蛋白的表达开始。多种心肌和骨骼肌肌钙蛋白T亚型共表达。心肌肌钙蛋白T的表达随时间的推移先升高后降低。荧光免疫细胞化学显示心肌肌钙蛋白T亚型掺入肌原纤维。在进行生物物理学研究时，平均肌管直径为12 μ m（范围5-25 μ m），平均长度为290 μ m（范围130-520 μ m）。在饥饿后6-7天，化学去皮的肌管产生的最大作用力为0.88 ± 0.12 μ N（平均值± 95%置信区间，n = 5），显著低于饥饿后10-13天的最大作用力1.12 ± 0.12 μ N（n = 7）（P < 0.05）。力-pCa关系产生的Hill系数为2.9 +/- 0.6（n = 7），pCa时的半数最大激活为5.77 +/- 0.20。C2 C12细胞的生物物理特性可以被测量，心肌和骨骼肌肌钙蛋白T亚型被纳入并共定位到肌原纤维中，这表明这些细胞可能是一个有用的模型，以评估外源性天然和突变的心脏和骨骼肌收缩蛋白亚型对肌丝功能的影响。
We examined the myofibril biochemical, structural, and biophysical properties of C2C12, a mouse skeletal muscle cell line (American Type Culture Collection), to assess whether force development and the sensitivity of the myofilaments to calcium could be measured in C2C12 myotubes and whether a cardiac contractile protein, troponin T, is expressed and incorporated into C2C12 myofibrils. When myoblasts fused and differentiated into myotubes, expression of myofilament proteins was initiated. Multiple cardiac and skeletal muscle troponin T isoforms were coexpressed. Cardiac troponin T expression increased and then decreased with time. Fluorescence immunocytochemistry demonstrated incorporation of cardiac troponin T isoforms into the myofibrils. At the time of the biophysical studies, mean myotube diameter was 12 mu m (range 5-25 mu m), and mean length was 290 mu m (range 130-520 mu m). The estimated maximum force developed by chemically skinned myotubes at 6-7 days poststarvation, 0.88 +/- 0.12 mu N (mean +/- 95% confidence interval, n = 5), was significantly less (P < 0.05) than that at 10-13 days poststarvation, 1.12 +/- 0.12 mu N (n = 7). The force-pCa relation yielded a Hill coefficient of 2.9 +/- 0.6 (n = 7) and half-maximal activation at pCa of 5.77 +/- 0.20. The demonstration that the biophysical properties of C2C12 cells can be measured and that cardiac and skeletal muscle troponin T isoforms are incorporated and colocalized into myofibrils suggest that these cells could be a useful model to assess the effects of exogenous native and mutated cardiac and skeletal contractile protein isoforms on myofilament function.