Direct measurement of oscillatory RhoA activity in embryonic cortical neurons stimulated with the axon guidance cue netrin-1 using fluorescence resonance energy transfer
Direct measurement of oscillatory RhoA activity in embryonic cortical neurons stimulated with the axon guidance cue netrin-1 using fluorescence resonance energy transfer
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DOI：
10.1111/boc.201500077
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发表时间：
2016-05-01
影响因子：
2.7
通讯作者：
Lamarche-Vane, Nathalie
中科院分区：
文献类型：
--
作者：
Antoine-Bertrand, Judith;Fu, Min;Lamarche-Vane, Nathalie
背景信息Rho GTP酶在神经系统发育过程中发挥着重要作用。它们诱导细胞骨架重排，这对轴突生长和引导的调节至关重要。一般认为，rac1和cdc42是轴突生长和引导的正向调节因子，而RhoA是负向调节因子。然而，对其活性的时空控制可以改变Rho GTP酶在轴突形态发生过程中的功能。在轴突引导信号下游的信号提示Netrin-1及其受体在结直肠癌(DCC)中被缺失，触发了rac1的激活和RhoA的抑制，从而促进了轴突的生长。然而，我们以前的工作也表明Netrin-1/DCC信号可以以时间和区域特定的方式激活RhoA。结果我们利用荧光共振能量转移技术在活体胚胎皮质神经元中观察到了Netrin-1对RhoA的激活。RhoA活性在未受刺激的神经元中振荡，Netrin-1在刺激5min后增加生长锥体中的振荡幅度。在这段时间内，netrin-1瞬间增加了RhoA的活性，并调节了RhoA的振荡模式。我们发现，在整个神经元、细胞体和生长细胞中，netrin-1诱导RhoA激活的时间是不同的。结论Netrin-1调节胚胎皮质神经元RhoA的时空激活。意义本研究首次证实了轴突引导线索netrin-1在神经元生长锥体中短期局部激活RhoA。
Background InformationRho GTPases play an essential role during the development of the nervous system. They induce cytoskeletal rearrangements that are critical for the regulation of axon outgrowth and guidance. It is generally accepted that Rac1 and Cdc42 are positive regulators of axon outgrowth and guidance, whereas RhoA is a negative regulator. However, spatiotemporal control of their activity can modify the function of Rho GTPases during axonal morphogenesis. Signalling downstream of the axon guidance cue netrin-1 and its receptor deleted in colorectal cancer (DCC) triggers the activation of Rac1 and the inhibition of RhoA to promote axon outgrowth. However, our previous work also suggests that netrin-1/DCC signalling can activate RhoA in a time- and region-specific manner.ResultsHere, we visualised RhoA activation in response to netrin-1 in live embryonic cortical neurons using fluorescence resonance energy transfer. RhoA activity oscillated in unstimulated neurons and netrin-1 increased the amplitude of the oscillations in growth cones after 5min of stimulation. Within this period of time, netrin-1 transiently increased RhoA activity and modulated the pattern of RhoA oscillations. We found that the timing of netrin-1-induced RhoA activation was different in whole neurons, cell bodies and growth cones.ConclusionsWe conclude that netrin-1 modulates the spatiotemporal activation of RhoA in embryonic cortical neurons.SignificanceThis study demonstrates for the first time the short-term localised activation of RhoA in neuronal growth cones by the axon guidance cue netrin-1.