Distribution of GAP-43, β-III tubulin and F-actin in developing and regenerating axons and their growth cones in vitro, following neurotrophin treatment
Distribution of GAP-43, β-III tubulin and F-actin in developing and regenerating axons and their growth cones in vitro, following neurotrophin treatment
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DOI：
10.1023/b:neur.0000021903.24849.6c
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发表时间：
2003-11-01
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影响因子：
--
通讯作者：
Bird, MM
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文献类型：
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作者：
Avwenagha, O;Campbell, G;Bird, MM
脑源性神经营养因子（BDNF）加入到胚胎和成人视网膜神经节细胞（RGC）轴突的外植体培养物中时，对其生长锥的大小和复杂性以及轴突中GAP-43、B-III微管蛋白和F-actin免疫反应产物的强度产生显着影响。GAP-43分布在轴突、板状伪足和丝状伪足中，而B-III微管蛋白沿着发育和成体再生轴突的长度分布，并且还分布在它们的生长锥的C-结构域中。BDNF处理的RGC生长锥较大，GAP-43和含微管分支的数量增加。虽然丝状伪足和lamellipodia失去了从发展和成人RGC生长锥后trkB-IgG治疗，所有这些分子的免疫反应产物的强度降低和trkB-IgG对轴突分布的B-III微管蛋白和GAP-43没有影响。BDNF处理的生长锥也表现出增加的F-肌动蛋白含有丝状伪足和轴突突起的数量。这项研究表明，第一次，trkB-IgG治疗导致的损失F-肌动蛋白的生长锥尖端的P-域中的发展和再生RGC轴突。虽然微管和F-肌动蛋白结构域通常保持不同的培养生长锥，B-III微管蛋白和F-肌动蛋白重叠的生长锥C-结构域内，并在轴突突起的成年RGC轴突，在较高浓度的BDNF。RGC生长锥的崩溃似乎与F-肌动蛋白的丢失相关。因此，在体外，trkB信号可能参与RGC轴突的维持和稳定，通过影响F-肌动蛋白聚合，稳定和分布。
Brain derived neurotrophic factor (BDNF) when added to explant cultures of both embryonic and adult retinal ganglion cell (RGC) axons exerted a marked effect on their growth cone size and complexity and also on the intensity of GAP-43, B-III tubulin and F-actin immunoreaction product in their axons. GAP-43 was distributed in axons, lamellipodia, and filopodia whereas B-III tubulin was distributed along the length of developing and adult regenerating axons and also in the C-domain of their growth cones. BDNF-treated developing RGC growth cones were larger and displayed increased numbers of GAP-43 and microtubule-containing branches. Although filopodia and lamellipodia were lost from both developing and adult RGC growth cones following trkB-IgG treatment, the intensity of the immunoreaction product of all these molecules was reduced and trkB-IgGs had no effect on the axonal distribution of B-III tubulin and GAP-43. BDNF-treated growth cones also displayed increased numbers of F-actin containing filopodia and axonal protrusions. This study demonstrates, for the first time, that trkB-IgG treatment causes the loss of F-actin in the P-domain of growth cone tips in developing and regenerating RGC axons. Although microtubules and F-actin domains normally remained distinct in cultured growth cones, B-III tubulin and F-actin overlapped within the growth cone C-domain, and within axonal protrusions of adult RGC axons, under higher concentrations of BDNF. The collapse of RGC growth cones appeared to correlate with the loss of F-actin. In vitro, trkB signalling may therefore be involved in the maintenance and stabilisation of RGC axons, by influencing F-actin polymerisation, stabilisation and distribution.