Asou H, Hamada K, Miyazaki T, Sakota T, Hayashi K, Takeda Y, Marret S, Delpech B, Itoh K, Uyemura K
Department of Physiology, Keio University School of Medicine, Tokyo, Japan.
J Neurosci Res. 1995 Mar 1;40(4):519-34. doi: 10.1002/jnr.490400411.
Oligodendrocyte precursor cells that develop into myelin-forming cells of the central nervous system (CNS) were cultured from newborn rat brain to study how they proliferate and differentiate in normal conditioning medium, and their cell development was characterized by scanning electron microscopy (SEM) observation and immunocytochemical studies. We have identified A2B5-negative pre-O2A progenitor cells (so-called "type-1" oligodendrocytes) in the secondary cultures on the astrocyte feeder layer. These cells are very small (diameter: 3.5 microns), round, and glossy, and develop into the process-bearing O2A progenitor cells (called "type-2" oligodendrocytes), which also express myelin basic protein (MBP) both in the cell body and in their cell processes. Finally, they develop into mature oligodendrocytes (called "type-3" oligodendrocytes). After MBP expression is elicited in these cells and MBP accumulates in the cell process in the area in contact with the axon, these cells are capable of forming the myelin sheath. Therefore, we examined the mechanism of myelin-sheath formation of "type-3" oligodendrocytes using video time-lapse movies, and demonstrated that these cells initially sent out processes to search for axons several times before the onset of myelination. Then thick filopodia extended towards the axon, and at the same time, the axonal part of neuron moved forward. Finally the ruffling lamellipodial parts wrapped up the axon similarly to a transverse wave with the secured thick filopodial process on the axon acting as scaffolding. These results suggest that our experimental systems are useful in studying normal oligodendrocyte development and their cellular biochemistry, as well as investigating the mechanism of myelin formation by oligodendrocytes.
从新生大鼠脑内培养出可发育为中枢神经系统（CNS）髓鞘形成细胞的少突胶质前体细胞，以研究它们在正常条件培养基中如何增殖和分化，并用扫描电子显微镜（SEM）观察和免疫细胞化学研究对其细胞发育进行表征。我们在星形胶质细胞饲养层上的传代培养物中鉴定出了A2B5阴性的前少突胶质前体细胞（所谓的“1型”少突胶质细胞）。这些细胞非常小（直径：3.5微米），呈圆形且有光泽，并发育为带有突起的少突胶质前体细胞（称为“2型”少突胶质细胞），其细胞体和细胞突起中均表达髓鞘碱性蛋白（MBP）。最终，它们发育为成熟的少突胶质细胞（称为“3型”少突胶质细胞）。在这些细胞中引发MBP表达且MBP在与轴突接触区域的细胞突起中积累后，这些细胞能够形成髓鞘。因此，我们使用视频延时电影检查了“3型”少突胶质细胞形成髓鞘的机制，并证明这些细胞在髓鞘形成开始前会多次伸出突起寻找轴突。然后粗丝状伪足向轴突延伸，与此同时，神经元的轴突部分向前移动。最后，褶皱状的片状伪足部分像横波一样包裹住轴突，轴突上固定的粗丝状伪足过程起到支架作用。这些结果表明，我们的实验系统可用于研究正常少突胶质细胞的发育及其细胞生物化学，以及研究少突胶质细胞形成髓鞘的机制。
