Zammit Peter S, Heslop Louise, Hudon Valérie, Rosenblatt J David, Tajbakhsh Shahragim, Buckingham Margaret E, Beauchamp Jonathan R, Partridge Terence A
Muscle Cell Biology Group, Medical Research Council Clinical Sciences Centre, Faculty of Medicine, Imperial College, Hammersmith Hospital Campus, Du Cane Road, London, United Kingdom.
Exp Cell Res. 2002 Nov 15;281(1):39-49. doi: 10.1006/excr.2002.5653.
The satellite cell compartment provides skeletal muscle with a remarkable capacity for regeneration. Here, we have used isolated myofibers to investigate the activation and proliferative potential of satellite cells. We have previously shown that satellite cells are heterogeneous: the majority express Myf5 and M-cadherin protein, presumably reflecting commitment to myogenesis, while a minority is negative for both. Although MyoD is rarely detected in quiescent satellite cells, over 98% of satellite cells contain MyoD within 24 h of stimulation. Significantly, MyoD is only observed in cells that are already expressing Myf5. In contrast, a minority population does not activate by the criteria of Myf5 or MyoD expression. Following the synchronous activation of the myogenic regulatory factor+ve satellite cells, their daughter myoblasts proliferate with a doubling time of approximately 17 h, irrespective of the fiber type (type I, IIa, or IIb) from which they originate. Although fast myofibers have fewer associated satellite cells than slow, and accordingly produce fewer myoblasts, each myofiber phenotype is associated with a complement of satellite cells that has sufficient proliferative potential to fully regenerate the parent myofiber within 4 days. This time course is similar to that observed in vivo following acute injury and indicates that cells other than satellite cells are not required for complete myofiber regeneration.
卫星细胞区室赋予骨骼肌显著的再生能力。在此，我们利用分离的肌纤维来研究卫星细胞的激活和增殖潜能。我们之前已经表明卫星细胞是异质性的：大多数表达Myf5和M-钙黏蛋白，这可能反映了其对成肌作用的定向分化，而少数细胞对两者均呈阴性。虽然在静止的卫星细胞中很少检测到MyoD，但超过98%的卫星细胞在刺激后24小时内含有MyoD。值得注意的是，MyoD仅在已经表达Myf5的细胞中观察到。相比之下，少数细胞群体根据Myf5或MyoD表达的标准并未被激活。在生肌调节因子阳性的卫星细胞同步激活后，它们的子代成肌细胞以约17小时的倍增时间进行增殖，无论它们起源于何种纤维类型（I型、IIa型或IIb型）。尽管快肌纤维比慢肌纤维相关的卫星细胞少，因此产生的成肌细胞也少，但每种肌纤维表型都与一组卫星细胞相关，这些卫星细胞具有足够的增殖潜能，能够在4天内完全再生亲代肌纤维。这个时间进程与急性损伤后在体内观察到的相似，表明完全的肌纤维再生不需要卫星细胞以外的其他细胞。
