Wnt/calcium signaling mediates axon growth and guidance in the developing corpus callosum.
Wnt/calcium signaling mediates axon growth and guidance in the developing corpus callosum.
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DOI：
10.1002/dneu.20846
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发表时间：
2011-04
影响因子：
3
通讯作者：
Kalil, Katherine
中科院分区：
文献类型：
--
作者：
Hutchins, B. Ian;Li, Li;Kalil, Katherine
体内研究表明，Wnt5a 梯度围绕胼胝体，并通过 Wnt5a 通过 Ryk 受体诱导的排斥力在中线之后引导胼胝体轴突（后交叉）。在分离的皮质培养物中，我们发现 Wnt5a 通过钙信号传导同时促进轴突生长和排斥。为了测试 Wnt5a/钙信号在复杂的体内环境中的作用，我们使用了含有发育中胼胝体的感觉运动皮层切片。将编码细胞质标记 DsRed 和基因编码钙指示剂 GCaMP2 的质粒电穿孔到一侧皮质半球中。交叉后的胼胝体轴突比交叉前的轴突生长快 50%，轴突和生长锥中钙瞬变的频率更高，与生长密切相关。将药物抑制剂应用于切片表明，涉及通过 IP3 受体释放钙和通过 TRP 通道钙进入的信号通路调节交叉后轴突的生长和引导。 Ryk siRNA 和 DsRed 的共电穿孔显示，Ryk 受体的敲低使后交叉轴突的生长率降低了 50%，但未降低预交叉轴突的生长率，并导致轴突错误路由。 Ryk 敲低导致轴突的引导错误是由于钙活性降低造成的。在胼胝体中，CaMKII 抑制降低了后交叉（但不是预交叉）轴突的生长率，并导致严重的引导错误，这是由于 Wnt/钙下游的 CaMKII 依赖性排斥力减少所致。我们首次表明，Wnt/Ryk 钙信号传导机制在皮质培养物中调节轴突生长和排斥，对于交叉后胼胝体轴突的正常生长和引导也至关重要，其中涉及通过 CaMKII 进行轴突排斥。 © 2010 Wiley periodicals, Inc. Develop Neurobiol 71: 269–283, 2011。
It has been shown in vivo that Wnt5a gradients surround the corpus callosum and guide callosal axons after the midline (postcrossing) by Wnt5a-induced repulsion via Ryk receptors. In dissociated cortical cultures we showed that Wnt5a simultaneously promotes axon outgrowth and repulsion by calcium signaling. Here to test the role of Wnt5a/calcium signaling in a complex in vivo environment we used sensorimotor cortical slices containing the developing corpus callosum. Plasmids encoding the cytoplasmic marker DsRed and the genetically encoded calcium indicator GCaMP2 were electroporated into one cortical hemisphere. Postcrossing callosal axons grew 50% faster than pre-crossing axons and higher frequencies of calcium transients in axons and growth cones correlated well with outgrowth. Application of pharmacological inhibitors to the slices showed that signaling pathways involving calcium release through IP3 receptors and calcium entry through TRP channels regulate post-crossing axon outgrowth and guidance. Co-electroporation of Ryk siRNA and DsRed revealed that knock down of the Ryk receptor reduced outgrowth rates of postcrossing but not precrossing axons by 50% and caused axon misrouting. Guidance errors in axons with Ryk knockdown resulted from reduced calcium activity. In the corpus callosum CaMKII inhibition reduced the outgrowth rate of postcrossing (but not precrossing) axons and caused severe guidance errors which resulted from reduced CaMKII-dependent repulsion downstream of Wnt/calcium. We show for the first time that Wnt/Ryk calcium signaling mechanisms regulating axon outgrowth and repulsion in cortical cultures are also essential for the proper growth and guidance of postcrossing callosal axons which involve axon repulsion through CaMKII. © 2010 Wiley Periodicals, Inc. Develop Neurobiol 71: 269–283, 2011.
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影响因子：
25
作者：
Liu, YB;Shi, J;Zou, YM
通讯作者：
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影响因子：
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