Growth cones turn and migrate up an immobilized gradient of the laminin IKVAV peptide
Growth cones turn and migrate up an immobilized gradient of the laminin IKVAV peptide
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DOI：
10.1002/neu.20075
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发表时间：
2005-01-01
期刊：
影响因子：
--
通讯作者：
Letourneau, PC
中科院分区：
文献类型：
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作者：
Adams, DN;Kao, EYC;Letourneau, PC
生长锥导航是由外在环境蛋白质引导的，这种蛋白质称为引导线索。许多体外研究已经表征了生长锥体在可溶引导线索上和下的梯度。尽管以前的研究表明轴突延长率可以由表面结合的分子的梯度来调节，但没有令人信服的证据表明生长锥体转向粘连配体或引导线索的表面结合的梯度上迁移。为了测试这种轴突引导模式，我们使用光固定化技术在聚苯乙烯培养皿表面创建了粘附层粘连蛋白多肽的网格和梯度。鸡胚胎背根神经节(DRGs)被放置在含有IKVAV多肽的表面结合梯度的多肽网格图案上。DRG生长锥沿着一条表面结合的多肽的路径到达垂直取向的梯度的中间，在30微米处有25%的浓度差。大多数生长锥翻转并沿坡度向上移动，直到它们直接朝向坡度向上。当生长锥遇到梯度时，它们的迁徙速度会减慢，但在梯度上升或下降后，生长锥的速度又恢复到以前的速度。这类似于体内的情况，在改变轴突延伸的方向之前，生长锥体在选择的点处放缓。因此，这些结果支持轴突引导机制包括通过表面结合的黏附分子的梯度和引导线索来定向生长锥的假说。(C)2004年威利期刊公司。
Growth cone navigation is guided by extrinsic environmental proteins, called guidance cues. Many in vitro studies have characterized growth cone turning up and down gradients of soluble guidance cues. Although previous studies have shown that axonal elongation rates can be regulated by gradients of surface-bound molecules, there are no convincing demonstrations of growth cones turning to migrate up a surface-bound gradient of an adhesive ligand or guidance cue. In order to test this mode of axonal guidance, we used a photo-immobilization technique to create grids and gradients of an adhesive laminin peptide on polystyrene culture dish surfaces. Chick embryo dorsal root ganglia (DRGs) were placed on peptide grid patterns containing surface-bound gradients of the IKVAV-containing peptide. DRG growth cones followed a path of surface-bound peptide to the middle of a perpendicularly oriented gradient with a 25 % concentration difference across 30 mum. The majority of growth cones turned and migrated up the gradient, turning until they were oriented directly up the gradient. Growth cones slowed their migration when they encountered the gradient, but growth cone velocity returned to the previous rate after turning up or down the gradient. This resembles in vivo situations where growth cones slow at a choice point before changing the direction of axonal extension. Thus, these results support the hypothesis that mechanisms of axonal guidance include growth cone orientation by gradients of surface-bound adhesive molecules and guidance cues. (C) 2004 Wiley Periodicals, Inc.