Wang C, Rougon G, Kiss J Z
Institute of Histology and Embryology, University of Geneva Medical School, Switzerland.
J Neurosci. 1994 Jul;14(7):4446-57. doi: 10.1523/JNEUROSCI.14-07-04446.1994.
While the capacity of O-2A oligodendrocyte progenitors to migrate in cell culture and during in vivo myelin formation is well documented, little is known about factors that regulate the motility of these cells. Here, we report on an in vitro model that allowed us to evaluate the contribution of alpha 2-8 linked polysialic acid (PSA) to O-2A cell motility. Using explant cultures of newborn rat neurohypophysis, we observed that individual glial fibrillary acidic protein (GFAP)-positive cells rapidly disperse from the explants, and that cells of the O-2A lineage predominate in the migratory cell pool. Presumed O-2A progenitor cells had a round or bipolar morphology and presented both A2B5 and GFAP immunoreactivity. When cultured in medium containing 10% fetal calf serum, these cells differentiated into stellate-shaped, A2B5/GFAP-positive type 2 astrocytes. In serum-free medium most of them developed into O4/galactocerebroside-positive oligodendrocytes. O-2A lineage cells were found only in a specific developmental period extending from embryonic day 21 to postnatal day 3. A monoclonal antibody, which recognizes the alpha 2-8 linked PSA, characteristic of the embryonic form of NCAM, revealed immunoreactivity on the surface of O-2A progenitor cells, whereas mature oligodendrocytes, type 2, type 1 astrocytes as well as flat GFAP-negative cells were negative. Treatment of the explants with endoneuraminidase purified from phage K1, which specifically removes PSA from the surface of the cell, resulted in a complete blockade of the dispersion of O-2A lineage population from the explant. The effects of the enzymatic treatment were both selective and reversible: migration of GFAP-negative fibroblast-like cells that are normally PSA negative was not influenced, and upon removal of the enzyme, cells of the O-2A lineage were readily detectable in the migrating population. These results provide direct evidence that alpha 2-8 linked PSA contribute to the motility of O-2A, glial progenitor cells.
虽然O-2A少突胶质前体细胞在细胞培养以及体内髓鞘形成过程中的迁移能力已有充分记录，但对于调节这些细胞运动性的因素却知之甚少。在此，我们报告了一种体外模型，该模型使我们能够评估α2-8连接的多唾液酸（PSA）对O-2A细胞运动性的作用。利用新生大鼠神经垂体的外植体培养，我们观察到单个胶质纤维酸性蛋白（GFAP）阳性细胞迅速从外植体中分散出来，并且O-2A谱系的细胞在迁移细胞群中占主导。推测的O-2A前体细胞具有圆形或双极形态，同时呈现A2B5和GFAP免疫反应性。当在含有10%胎牛血清的培养基中培养时，这些细胞分化为星形、A2B5/GFAP阳性的2型星形胶质细胞。在无血清培养基中，它们中的大多数发育为O4/半乳糖脑苷脂阳性的少突胶质细胞。仅在从胚胎第21天到出生后第3天的特定发育时期发现O-2A谱系细胞。一种识别α2-8连接的PSA（NCAM胚胎形式的特征）的单克隆抗体，在O-2A前体细胞表面显示出免疫反应性，而成熟少突胶质细胞、2型、1型星形胶质细胞以及扁平的GFAP阴性细胞均为阴性。用从噬菌体K1中纯化的神经氨酸酶处理外植体，该酶可特异性地从细胞表面去除PSA，导致O-2A谱系群体从外植体的分散完全受阻。酶处理的效果具有选择性且可逆：通常PSA阴性的GFAP阴性成纤维细胞样细胞的迁移不受影响，并且在去除酶后，O-2A谱系的细胞在迁移群体中很容易被检测到。这些结果提供了直接证据，表明α2-8连接的PSA有助于O-2A胶质前体细胞的运动性。
