Neuron-glia cell adhesion molecule interacts with neurons and astroglia via different binding mechanisms.
Neuron-glia cell adhesion molecule interacts with neurons and astroglia via different binding mechanisms.
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DOI：
10.1083/jcb.106.2.487
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发表时间：
1988-02
期刊：
影响因子：
--
通讯作者：
Edelman GM
中科院分区：
文献类型：
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作者：
Grumet M;Edelman GM
神经元-胶质细胞粘附分子 (Ng-CAM) 存在于中枢神经系统的有丝分裂后神经元以及神经元和施万细胞的外周。它与神经元之间以及神经元与神经胶质细胞之间的结合有关。为了了解 Ng-CAM 结合的分子机制，我们分析了固定在 0.5 微米珠子 (Covaspheres) 上或重构到脂质体中的小鸡 Ng-CAM 的聚集。结果与这些颗粒与不同类型细胞的结合以及细胞与细胞结合本身相关。 Ng-CAM-Covaspheres和Ng-CAM脂质体均单独自聚集，并且针对Ng-CAM的抗体强烈抑制它们的聚集；聚集速率大约随着珠子或脂质体浓度的平方而增加。当脂质体中 Ng-CAM 与脂质的比例增加时，观察到更高的聚集率。 Covaspheres 上和脂质体中的放射性碘化 Ng-CAM 与神经元和神经胶质细胞结合，并且在每种情况下，针对 Ng-CAM 的抗体抑制 50-90% 的结合。成纤维细胞和脑膜细胞的对照制剂没有表现出显着的结合。在定义每种细胞类型的标记以及剪切、温度和细胞密度的最佳条件后，通过细胞测定探索了物种内和物种间（小鸡和小鼠）的神经元和神经胶质细胞之间的粘附。如先前使用鸡细胞所指出的(Grumet，M.，S.Hoffman，C.-M.Chuong，和G.M.Edelman.1984 Proc.Natl.Acad.Sci.USA.81：7989-7993)，抗Ng-CAM抗体抑制神经元-神经元和神经元-胶质细胞结合。在跨物种粘附测定中，小鸡神经元与小鼠星形胶质细胞的结合以及小鼠神经元与小鸡星形胶质细胞的结合均被抗Ng-CAM抗体抑制。为了确定Ng-CAM的细胞配体在神经元-神经元和神经元-神经胶质结合方面是否不同，将细胞与特异性抗体一起预孵育，通过洗涤除去抗体，并测量Ng-CAM-Covasphere结合。将神经元与抗 Ng-CAM 抗体预孵育会抑制 Ng-CAM-Covasphere 结合，但类似的星形胶质细胞预孵育不会抑制结合。相反，将星形胶质细胞与抗星形胶质细胞抗体预孵育会抑制与这些细胞的结合，但将神经元与这些抗体预孵育则没有效果。结合 Covaspheres 和脂质体聚集的数据，这些发现表明 Ng-CAM-Covaspheres 与神经元上的 Ng-CAM 结合，但与星形胶质细胞上的不同分子结合。（摘要截断为 400 字）
The neuron-glia cell adhesion molecule (Ng-CAM) is present in the central nervous system on postmitotic neurons and in the periphery on neurons and Schwann cells. It has been implicated in binding between neurons and between neurons and glia. To understand the molecular mechanisms of Ng-CAM binding, we analyzed the aggregation of chick Ng- CAM either immobilized on 0.5-micron beads (Covaspheres) or reconstituted into liposomes. The results were correlated with the binding of these particles to different types of cells as well as with cell-cell binding itself. Both Ng-CAM-Covaspheres and Ng-CAM liposomes individually self-aggregated, and antibodies against Ng-CAM strongly inhibited their aggregation; the rate of aggregation increased approximately with the square of the concentration of the beads or the liposomes. Much higher rates of aggregation were observed when the ratio of Ng-CAM to lipid in the liposome was increased. Radioiodinated Ng-CAM on Covaspheres and in liposomes bound both to neurons and to glial cells and in each case antibodies against Ng-CAM inhibited 50-90% of the binding. Control preparations of fibroblasts and meningeal cells did not exhibit significant binding. Adhesion between neurons and glia within and across species (chick and mouse) was explored in cellular assays after defining markers for each cell type, and optimal conditions of shear, temperature, and cell density. As previously noted using chick cells (Grumet, M., S. Hoffman, C.-M. Chuong, and G. M. Edelman. 1984 Proc. Natl. Acad. Sci. USA. 81:7989-7993), anti-Ng-CAM antibodies inhibited neuron-neuron and neuron-glia binding. In cross- species adhesion assays, binding of chick neurons to mouse astroglia and binding of mouse neurons to chick astroglia were both inhibited by anti-Ng-CAM antibodies. To identify whether the cellular ligands for Ng- CAM differed for neuron-neuron and neuron-glia binding, cells were preincubated with specific antibodies, the antibodies were removed by washing, and Ng-CAM-Covasphere binding was measured. Preincubation of neurons with anti-Ng-CAM antibodies inhibited Ng-CAM-Covasphere binding but similar preincubation of astroglial cells did not inhibit binding. In contrast, preincubation of astroglia with anti-astroglial cell antibodies inhibited binding to these cells but preincubation of neurons with these antibodies had no effect. Together with the data on Covaspheres and liposome aggregation, these findings suggested that Ng- CAM-Covaspheres bound to Ng-CAM on neurons but bound to different molecules on astroglia.(ABSTRACT TRUNCATED AT 400 WORDS)