Bambrick L L, de Grip A, Seenivasan V, Krueger B K, Yarowsky P J
Department of Physiology, University of Maryland School of Medicine, Baltimore 21201, USA.
J Neurosci Res. 1996 Nov 1;46(3):305-15. doi: 10.1002/(SICI)1097-4547(19961101)46:3<305::AID-JNR3>3.0.CO;2-O.
Expression of developmentally regulated antigens was used to characterize glial cells in cultures from embryonic mouse cerebral cortex. Over 90% of the cells had a flat morphology, and about 50% of these flat cells also expressed the ganglioside GD3. Up to 40% of all the GD3 expressing cells also expressed A2B5 antigen. Flat cells expressing either glial fibrillary acidic protein (GFAP), or GD3 or both were present at all times in vitro. These three populations of flat cells could not be further distinguished on the basis of NG2 or fibronectin expression, or with respect to their responses to the mitogens FGF-2, PDGF, or EGF. The glial cultures also contain a small number (approximately 5%) of process bearing cells with the morphological and immunocytochemical characteristics of oligodendrocyte precursors. The expression of GD3 by flat cells changed with time in culture as the fraction of flat cells expressing only GD3 declined and the fraction of cells expressing GFAP (with or without GD3) increased. The data are consistent with those flat cells expressing only GD3 being astrocyte precursors. Furthermore, between 1 and 3 weeks in vitro GD3/GFAP cells lose GD3 while retaining GFAP. Cells expressing only GFAP could be induced to express GD3 and A2B5 by treatment with FGF-2. The widespread and regulated expression of GD3 and A2B5 by murine glia is different from the restricted pattern of expression previously reported for these antigens in rat brain cell cultures. These results demonstrate that expression of GD3 and A2B5 by murine astrocytes depends on both culture age and extracellular signals and that these gangliosides are not markers for cell lineage in the mouse.
利用发育调控抗原的表达来表征来自胚胎小鼠大脑皮质培养物中的神经胶质细胞。超过90%的细胞具有扁平形态，并且这些扁平细胞中约50%也表达神经节苷脂GD3。所有表达GD3的细胞中高达40%也表达A2B5抗原。表达胶质纤维酸性蛋白（GFAP）、GD3或两者的扁平细胞在体外任何时候都存在。这三类扁平细胞在NG2或纤连蛋白表达方面，或在它们对有丝分裂原FGF-2、PDGF或EGF的反应方面无法进一步区分。神经胶质细胞培养物中还含有少量（约5%）具有少突胶质细胞前体形态和免疫细胞化学特征的有突起细胞。随着培养时间的推移，扁平细胞中GD3的表达发生变化，因为仅表达GD3的扁平细胞比例下降，而表达GFAP（有或没有GD3）的细胞比例增加。这些数据与仅表达GD3的扁平细胞是星形胶质细胞前体一致。此外，在体外培养1至3周期间，GD3/GFAP细胞失去GD3但保留GFAP。仅表达GFAP的细胞经FGF-2处理后可被诱导表达GD3和A2B5。小鼠神经胶质细胞对GD3和A2B5的广泛且受调控的表达与先前报道的这些抗原在大鼠脑细胞培养物中的限制性表达模式不同。这些结果表明，小鼠星形胶质细胞对GD3和A2B5的表达取决于培养年龄和细胞外信号，并且这些神经节苷脂不是小鼠细胞谱系的标志物。
