Feldman J L, Stockdale F E
Department of Medicine, Stanford University School of Medicine, California 94305-5306.
Dev Biol. 1991 Feb;143(2):320-34. doi: 10.1016/0012-1606(91)90083-f.
Following skeletal muscle injury, new fibers form from resident satellite cells which reestablish the fiber composition of the original muscle. We have used a cell culture system to analyze satellite cells isolated from adult chicken and quail pectoralis major (PM; a fast muscle) and anterior latissimus dorsi (ALD; a slow muscle) to determine if satellite cells isolated from fast or slow muscles produce one or several types of fibers when they form new fibers in vitro in the absence of innervation or a specific extracellular milieu. The types of fibers formed in satellite cell cultures were determined using immunoblotting and immunocytochemistry with monoclonal antibodies specific for avian fast and slow myosin heavy chain (MHC) isoforms. We found that satellite cells were of different types and that fast and slow muscles differed in the percentage of each type they contained. Primary satellite cells isolated from the PM formed only fast fibers, while up to 25% of those isolated from ALD formed fibers that were both fast and slow (fast/slow fibers), the remainder being fast only. Fast/slow fibers formed from chicken satellite cells expressed slow MHC1, while slow MHC2 predominated in fast/slow fibers formed from quail satellite cells. Prolonged primary culture did not alter the relative proportions of fast to fast/slow fibers in high density cultures of either chicken or quail satellite cells. No change in commitment was observed in fibers formed from chicken satellite cell progeny repeatedly subcultured at high density, while fibers formed from subcultured quail satellite cell progeny demonstrated increasing commitment to fast/slow fiber type formation. Quail satellite cells cloned from high density cultures formed colonies that demonstrated a similar change in commitment from fast to fast/slow, as did serially subcloned individual satellite cell progeny, indicating that the observed change from fast to fast/slow differentiation resulted from intrinsic changes within a satellite cell. Thus satellite cells freshly isolated from adult chicken and quail are committed to form fibers of at least two types, satellite cells of these two types are found in different proportions in fast and slow muscles, and repeated cell proliferation of quail satellite cell progeny may alter satellite cell progeny to increasingly form fibers of a single type.
骨骼肌损伤后，新的肌纤维由驻留的卫星细胞形成，这些卫星细胞重新建立了原始肌肉的纤维组成。我们使用细胞培养系统分析从成年鸡和鹌鹑的胸大肌（PM；快肌）和背阔肌前部（ALD；慢肌）分离出的卫星细胞，以确定在无神经支配或特定细胞外环境的情况下，从快肌或慢肌分离出的卫星细胞在体外形成新纤维时是否产生一种或几种类型的纤维。使用针对禽类快、慢肌球蛋白重链（MHC）同工型的单克隆抗体，通过免疫印迹和免疫细胞化学确定卫星细胞培养物中形成的纤维类型。我们发现卫星细胞有不同类型，快肌和慢肌所含每种类型的百分比不同。从胸大肌分离的原代卫星细胞仅形成快肌纤维，而从背阔肌前部分离的卫星细胞中高达25%形成快肌和慢肌纤维（快/慢肌纤维），其余仅为快肌纤维。鸡卫星细胞形成的快/慢肌纤维表达慢肌MHC1，而鹌鹑卫星细胞形成的快/慢肌纤维中慢肌MHC2占主导。长时间的原代培养并未改变鸡或鹌鹑卫星细胞高密度培养物中快肌纤维与快/慢肌纤维的相对比例。在高密度反复传代培养的鸡卫星细胞后代形成的纤维中未观察到分化倾向的变化，而传代培养的鹌鹑卫星细胞后代形成的纤维显示出对快/慢肌纤维类型形成的分化倾向增加。从高密度培养物中克隆的鹌鹑卫星细胞形成的集落显示出从快肌到快/慢肌的类似分化倾向变化，连续亚克隆的单个卫星细胞后代也是如此，这表明观察到的从快肌到快/慢肌分化的变化是由卫星细胞内的内在变化引起的。因此，从成年鸡和鹌鹑新鲜分离的卫星细胞倾向于形成至少两种类型的纤维，这两种类型的卫星细胞在快肌和慢肌中的比例不同，鹌鹑卫星细胞后代的反复细胞增殖可能会使卫星细胞后代越来越多地形成单一类型的纤维。
