钾离子通道Kv10.2超敏与婴儿/儿童癫痫点燃的机制研究

Epileptic encephalopathies (EES) of infancy and childhood, which are devastating disorders characterized by frequent epileptic seizures, are closely associated with ion channel mutations and dysfunctions. We recently identified mutations of voltage-gated potassium channel Kv10.2 in child with EES. Our investigation found that an Arginine to Histidine mutation at position 327 (R327H), which occurs in the conserved voltage-sensing domain, contributes to the hyperpolarization of Kv10.2 channel activation. However, how Kv10.2 channel and its mutation affect the function of the brain, especially the hippocampus, a critical region for the onset of epilepsy, is largely unknown. Based on our previous work, we propose to test the following hypothesis: gain-of-function Kv10.2 mutation leads to the hyperpolarization of channel activation, resulting in the alternation of neuronal firing and dysfunction of neuronal network, eventually causing EES. This proposal takes advantage of the preliminary work we generated, utilizing a wide range of technologies, including voltage-clamp, current-clamp, and multi-electrode array recording, to study the dissociated excitatory pyramidal neurons/inhibitory bipolar neurons and brain slices of hippocampus. This study will reveal the molecular and cellular mechanisms underlying how Kv10.2 channel and its mutations affect the function of hippocampal neurons and neural network, providing new targets for the treatment of EES of infancy and childhood.

婴儿/儿童癫痫性脑病的发生、发展与离子通道结构功能异常紧密相关。我们近期研究发现：Kv10.2电压门控钾离子通道基因突变存在于癫痫孩童，Kv10.2电压感应区一精氨酸突变成组氨酸(R327H)，诱发Kv10.2电压超敏。然而，Kv10.2在癫痫发作先导区海马的生理功能、Kv10.2与癫痫发作的关联机制，至今未明。基于前期的奠基性工作，我们提出“Kv10.2基因突变致其自身对电压超敏，诱发海马神经细胞及神经网络电活动平衡紊乱，最终点燃癫痫”的假说。本课题拟在前期研究基础上，采用离体神经元与脑片电生理记录、高通量多电极点阵记录、病毒转染等技术，深入研究：①Kv10.2突变体分别对海马兴奋性与抑制性两类神经元电活动的影响机制；②Kv10.2突变体对整个海马神经网络电活动平衡的影响机制。本研究将原创性地剖析海马Kv10.2诱发神经网络电活动平衡紊乱的精细机制，以期为癫痫治疗提供新的药物作用靶点。

电压门控钾离子通道功能紊乱对癫痫发生发展起重要作用，本项目较为深入的研究了电压门控钾离子通道Kv10.2调控颞叶癫痫的分子及神经机制。研究结果发现并证实: 1. 颞叶癫痫导致大鼠海马区Kv10.2蛋白显著下调, 诱发焦虑样情绪，学习记忆功能损伤。拯救Kv10.2蛋白可明显改善焦虑样行为及工作记忆能力； 2. Kv10.2蛋白敲除后改变神经元细胞的形态，增加了神经元细胞的兴奋性；3. Kv10.2缺失增加了大鼠癫痫易感性，改变了兴奋性和抑制性两类神经元蛋白表达水平。这些成果不仅丰富了Kv10.2与癫痫的理论，为治疗癫痫提供了新的理论基础，也为临床治疗癫痫提供新的手段和策略。在本项目资助下，已发表SCI论文2篇。