The transition from proliferation to differentiation is delayed in satellite cells from mice lacking MyoD
The transition from proliferation to differentiation is delayed in satellite cells from mice lacking MyoD
复制标题
DOI：
10.1006/dbio.1999.9284
复制
发表时间：
1999-06-15
影响因子：
2.7
通讯作者：
Natanson, P
中科院分区：
文献类型：
--
作者：
Yablonka-Reuveni, Z;Rudnicki, MA;Natanson, P
来自成年大鼠肌肉的卫星细胞在进入细胞周期后共表达增殖细胞核抗原和MyoD，这表明MyoD在卫星细胞的募集过程中起作用。此外，在MyoD-/-小鼠中肌肉再生受损的发现为MyoD在成人肌肉中肌发生期间的作用提供了证据。为了进一步了解MyoD在成人肌发生过程中的作用，我们比较了MyoD-/-和野生型小鼠的卫星细胞，因为它们在单肌纤维培养物和组织分离细胞培养物（原代培养物）中通过肌发生进展。使用针对各种调节蛋白的抗体，化学追踪进行增殖和分化的卫星细胞。此外，针对丝裂原活化蛋白激酶ERK 1和ERK 2的抗体被用于定位纤维相关卫星细胞的细胞质，而不管它们表达特异性生肌调节因子蛋白的能力。我们表明，在最初的几天在文化中的肌纤维分离的MyoD-/-和野生型小鼠含有相同数量的增殖，ERK+卫星细胞。然而，MyoD-/-卫星细胞继续增殖，并且只有非常少量的细胞转变为肌细胞生成素+状态，而野生型细胞退出增殖区室并进入肌细胞生成素+阶段。分析MyoD-/-卫星细胞的组织分离培养物，我们鉴定了许多细胞，其细胞核对Myf 5蛋白呈阳性。相比之下，由于存在低水平的Myf 5蛋白，野生型培养物中Myf 5+细胞的定量是困难的。MyoD-/-培养物中的Myf 5+细胞中有10个结蛋白呈阳性，与野生型培养物中的MyoD+细胞相似。在MyoD-/-原代培养物中鉴定了肌细胞生成素+细胞，但与野生型细胞相比，它们的出现延迟。这些“延迟的”肌细胞生成素+细胞可以表达其他分化标记物，如MEF 2A和细胞周期蛋白D3，并融合成肌管。总之，我们的研究表明，MyoD的存在是卫星细胞正常进展成肌细胞生成素+，分化状态的关键。进一步提出Myf 5 +/MyoD-表型可能代表能够在成人肌肉中维持肌源性前体库的肌源性干细胞区室。(C)北京：科学出版社.
Satellite cells from adult rat muscle coexpress proliferating cell nuclear antigen and MyoD upon entry into the cell cycle, suggesting that MyoD plays a role during the recruitment of satellite cells. Moreover, the finding that muscle regeneration is compromised in MyoD-/- mice, has provided evidence for the role of MyoD during myogenesis in adult muscle. In order to gain further insight into the role of MyoD during myogenesis in the adult, we compared satellite cells from MyoD-/- and wildtype mice as they progress through myogenesis in single-myofiber cultures and in tissue-dissociated cell cultures (primary cultures). Satellite cells undergoing proliferation and differentiation were traced immunohistochemically using antibodies against various regulatory proteins. In addition, an antibody against the mitogen-activated protein kinases ERK1 and ERK2 was used to localize the cytoplasm of the fiber-associated satellite cells regardless of their ability to express specific myogenic regulatory factor proteins. We show that during the initial days in culture the myofibers isolated from both the MyoD-/- and the wildtype mice contain the same number of proliferating, ERK+ satellite cells. However, the MyoD-/- satellite cells continue to proliferate and only a very small number of cells transit into the myogenin+ state, whereas the wildtype cells exit the proliferative compartment and enter the myogenin+ stage. Analyzing tissue-dissociated cultures of MyoD-/- satellite cells, we identified numerous cells whose nuclei were positive for the Myf5 protein. In contrast, quantification of Myf5+ cells in the wildtype cultures was difficult due to the low level of Myf5 protein present. The Myf5+ cells in the MyoD-/- cultures were of ten positive for desmin, similar to the MyoD+ cells in the wildtype cultures. Myogenin+ cells were identified in the MyoD-/- primary cultures, but their appearance was delayed compared to the wildtype cells. These "delayed" myogenin+ cells can express other differentiation markers such as MEF2A and cyclin D3 and fuse into myotubes. Taken together, our studies suggest that the presence of MyoD is critical for the normal progression of satellite cells into the myogenin+, differentiative state. It is further proposed that the Myf5+/MyoD- phenotype may represent the myogenic stem cell compartment which is capable of maintaining the myogenic precursor pool in the adult muscle. (C) 1999 Academic Press.