Netrin-1 Promotes Excitatory Synaptogenesis between Cortical Neurons by Initiating Synapse Assembly
Netrin-1 Promotes Excitatory Synaptogenesis between Cortical Neurons by Initiating Synapse Assembly
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DOI：
10.1523/jneurosci.1085-13.2013
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发表时间：
2013-10-30
影响因子：
5.3
通讯作者：
Kennedy, Timothy E.
中科院分区：
文献类型：
--
作者：
Goldman, Jennifer S.;Ashour, Mohammed A.;Kennedy, Timothy E.
Netrin-1是一种分泌蛋白，在神经回路形成的早期阶段指导长距离轴突引导，并在突触形成高峰的出生后时期继续在哺乳动物前脑中表达。在这里，我们展示了netrin-1在大鼠和小鼠皮层神经元中的突触发生功能，并探讨其潜在机制。netrin-1及其受体DCC在发育中的哺乳动物皮层神经元中广泛表达，并在体内突触中富集。我们检测DCC蛋白分布沿着培养的皮层神经元的轴突和树突，并提供证据，新翻译netrin-1被选择性地运输到树突。使用获得和丧失功能的操作，我们证明netrin-1增加了发育中的皮层神经元之间兴奋性突触的数量和强度。我们发现netrin-1增加了轴突和树突的复杂性，从而增加了接触的可能性。在接触部位，netrin-1促进粘附，同时通过Src家族激酶信号传导和m-Tor依赖性蛋白翻译局部富集和重组潜在的肌动蛋白细胞骨架，以局部聚集突触前和突触后蛋白。最后，我们使用全细胞膜片钳电生理学证明netrin-1增加皮层锥体神经元记录的mEPSC的频率和振幅。这些发现将netrin-1鉴定为促进哺乳动物皮层神经元之间突触发生的突触富集蛋白。
Netrin-1 is a secreted protein that directs long-range axon guidance during early stages of neural circuit formation and continues to be expressed in the mammalian forebrain during the postnatal period of peak synapse formation. Here we demonstrate a synaptogenic function of netrin-1 in rat and mouse cortical neurons and investigate the underlying mechanism. Wereport that netrin-1 and its receptor DCC are widely expressed by neurons in the developing mammalian cortex during synapse formation and are enriched at synapses in vivo. We detect DCC protein distributed along the axons and dendrites of cultured cortical neurons and provide evidence that newly translated netrin-1 is selectively transported to dendrites. Using gain and loss of function manipulations, we demonstrate that netrin-1 increases the number and strength of excitatory synapsesmadebetween developing cortical neurons. Weshow that netrin-1 increases the complexity of axon and dendrite arbors, thereby increasing the probability of contact. At sites of contact, netrin-1 promotes adhesion, while locally enriching and reorganizing the underlying actin cytoskeleton through Src family kinase signaling and m-Tor-dependent protein translation to locally cluster presynaptic and postsynaptic proteins. Finally, we demonstrate using whole-cell patch-clamp electrophysiology that netrin-1 increases the frequency and amplitude of mEPSCs recorded from cortical pyramidal neurons. These findings identify netrin-1 as a synapse-enriched protein that promotes synaptogenesis between mammalian cortical neurons.