Lochter A, Schachner M
Department of Neurobiology, Swiss Federal Institute of Technology, Zürich.
J Neurosci. 1993 Sep;13(9):3986-4000. doi: 10.1523/JNEUROSCI.13-09-03986.1993.
The extracellular matrix molecules tenascin, laminin, and fibronectin, the cell adhesion molecule L1, and the lectin concanavalin A (ConA) were tested for their effects on neuritogenesis in cultures of hippocampal neurons. We analyzed neurite outgrowth between 3 and 21 hr after plating and found that, on polyornithine as control substrate, lengths of axon-like major neurites and dendrite-like minor neurites increased continuously with time in culture. Moreover, growth of minor neurites was faster than growth of major neurites. When the extracellular matrix molecules tenascin, laminin, and fibronectin were coated on polyornithine substrates, growth of all neurites was faster than on control substrates during the first hours of culture. After this initial phase of enhanced neurite outgrowth, elongation of major neurites continued at a higher rate than on the control substrate and growth of minor neurites ceased after 12 hr. Correspondingly, neuronal polarity was strongly increased on the extracellular matrix substrates during later phases of culture. In contrast, lengths of both major and minor neurites were increased over control values on L1 and ConA substrates at all time points investigated. Thus, neuronal polarity was similar for control, L1, and ConA substrates. Spreading of neuronal cell bodies was reduced by about 50% on tenascin, laminin, and fibronectin and by less than 20% on L1 and ConA substrates after 21 hr of culture, when compared to the control substrate. Neuron-to-substrate adhesion was reduced on all three extracellular matrix substrates but not affected on L1 or ConA substrates, after 3 and 21 hr of culture. These observations indicate that induction of neuronal polarity is not a general feature of neurite outgrowth-promoting molecules, such as L1 or ConA, but a distinctive property of the three extracellular matrix glycoproteins studied, and may suggest that enhancement of polarity is correlated with decreased strength of adhesion.
对细胞外基质分子腱生蛋白、层粘连蛋白和纤连蛋白、细胞粘附分子L1以及凝集素刀豆球蛋白A（ConA）对海马神经元培养中神经突形成的影响进行了测试。我们分析了接种后3至21小时内的神经突生长情况，发现在作为对照底物的聚鸟氨酸上，轴突样主要神经突和树突样次要神经突的长度在培养过程中随时间持续增加。此外，次要神经突的生长速度比主要神经突快。当腱生蛋白、层粘连蛋白和纤连蛋白等细胞外基质分子包被在聚鸟氨酸底物上时，在培养的最初几个小时内，所有神经突的生长都比在对照底物上快。在神经突生长增强的这个初始阶段之后，主要神经突的伸长继续以高于对照底物的速率进行，而次要神经突的生长在12小时后停止。相应地，在培养的后期阶段，细胞外基质底物上的神经元极性显著增加。相比之下，在所有研究的时间点，主要和次要神经突的长度在L1和ConA底物上均高于对照值。因此，对照、L1和ConA底物上的神经元极性相似。培养21小时后，与对照底物相比，腱生蛋白、层粘连蛋白和纤连蛋白上神经元细胞体的铺展减少了约50%，而L1和ConA底物上减少了不到20%。培养3小时和21小时后，所有三种细胞外基质底物上的神经元与底物的粘附均降低，但L1或ConA底物上未受影响。这些观察结果表明，神经元极性的诱导不是促进神经突生长的分子（如L1或ConA）的普遍特征，而是所研究的三种细胞外基质糖蛋白的独特特性，并且可能表明极性的增强与粘附强度的降低相关。
