Zhou Xuhong, Zhuang Fei, Li Hong, Zheng Kun, Hong Ze, Feng Weijing, Zhou Wendi, Chen Jian
The Second People's Hospital of Huai'an Huai'an, China.
Huai'an First People's Hospital, Nanjing Medical University Huai'an, China.
Am J Transl Res. 2016 Dec 15;8(12):5610-5618. eCollection 2016.
Epilepsy is linked to mutations in KCNQ channels. KCNQ channels including KCNQ2 and KCNQ3 are enriched in neurons, regulating action potential generation and modulation. Here, we showed that properties of KCNQ2 channel in rat hippocampal cultured neurons are regulated by ubiquitous calcium sensor calmodulin. We analyzed calmodulin function on the KCNQ2 channel in both HEK293 cells and neurons. We used shRNAs to suppress expression of calmodulin protein. On the other hand, we used cDNA to over-express calmodulin in HEK293 and neuron cells. In wild type and mis-sense mutations of KCNQ2 proteins, calmodulin over-expression enhanced outward K current and decreased neuronal activity. Meanwhile, calmodulin knockdown reduced KCNQ2 current and increased neuronal activity, showing that hippocampal neuronal excitability is regulated by expression level of calmodulin protein. Our data suggest that calmodulin performs a major function in regulating KCNQ2 properties via direct binding to KCNQ2 protein, indicating that calmodulin could be a target of as gene therapy in epilepsy.
癫痫与KCNQ通道的突变有关。包括KCNQ2和KCNQ3在内的KCNQ通道在神经元中富集，调节动作电位的产生和调节。在此，我们表明大鼠海马培养神经元中KCNQ2通道的特性受普遍存在的钙传感器钙调蛋白调节。我们分析了钙调蛋白在HEK293细胞和神经元中对KCNQ2通道的作用。我们使用短发夹RNA（shRNAs）抑制钙调蛋白的表达。另一方面，我们使用互补DNA（cDNA）在HEK293细胞和神经元细胞中过表达钙调蛋白。在KCNQ2蛋白的野生型和错义突变中，钙调蛋白的过表达增强了外向钾电流并降低了神经元活性。同时，钙调蛋白敲低减少了KCNQ2电流并增加了神经元活性，表明海马神经元兴奋性受钙调蛋白表达水平的调节。我们的数据表明钙调蛋白通过直接与KCNQ2蛋白结合在调节KCNQ2特性方面发挥主要作用，这表明钙调蛋白可能成为癫痫基因治疗的靶点。
