An Ion Transport-Independent Role for the Cation-Chloride Cotransporter KCC2 in Dendritic Spinogenesis In Vivo
An Ion Transport-Independent Role for the Cation-Chloride Cotransporter KCC2 in Dendritic Spinogenesis In Vivo
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DOI：
10.1093/cercor/bhs027
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发表时间：
2013-02-01
期刊：
影响因子：
3.7
通讯作者：
Vutskits, Laszlo
中科院分区：
文献类型：
--
作者：
Fiumelli, Hubert;Briner, Adrian;Vutskits, Laszlo
神经元特异性K-Cl协同转运蛋白KCC 2在锥体神经元的兴奋性突触附近高度表达，最近的体外数据表明该蛋白在树突棘的发育中起作用。然而，这些观察结果的体内相关性尚不清楚。使用在子宫内电穿孔结合事后离子电渗注射的荧光黄，我们表明，过早表达KCC 2诱导高度显着和永久性增加树突棘密度层2/3锥体神经元在体感皮层。全细胞记录显示，这种增加的棘密度与KCC 2转染的神经元中增强的自发兴奋活动相关。缺乏氯转运蛋白功能的KCC 2的N-末端缺失形式的过早表达也增加了棘密度。与此相反，在子宫内电穿孔的KCC 2（KCC 2-C568 A）的点突变体，共转运蛋白的功能和与细胞骨架的相互作用被破坏后，没有观察到对棘密度的影响。转染KCC 2的C-末端结构域，一个参与与树突细胞骨架相互作用的区域，也增加了棘密度。总的来说，这些结果证明了KCC 2在体内兴奋性突触发生中的作用，通过一种独立于其离子转运功能的机制。
The neuron-specific K-Cl cotransporter, KCC2, is highly expressed in the vicinity of excitatory synapses in pyramidal neurons, and recent in vitro data suggest that this protein plays a role in the development of dendritic spines. The in vivo relevance of these observations is, however, unknown. Using in utero electroporation combined with post hoc iontophoretic injection of Lucifer Yellow, we show that premature expression of KCC2 induces a highly significant and permanent increase in dendritic spine density of layer 2/3 pyramidal neurons in the somatosensory cortex. Whole-cell recordings revealed that this increased spine density is correlated with an enhanced spontaneous excitatory activity in KCC2-transfected neurons. Precocious expression of the N-terminal deleted form of KCC2, which lacks the chloride transporter function, also increased spine density. In contrast, no effect on spine density was observed following in utero electroporation of a point mutant of KCC2 (KCC2-C568A) where both the cotransporter function and the interaction with the cytoskeleton are disrupted. Transfection of the C-terminal domain of KCC2, a region involved in the interaction with the dendritic cytoskeleton, also increased spine density. Collectively, these results demonstrate a role for KCC2 in excitatory synaptogenesis in vivo through a mechanism that is independent of its ion transport function.