Aβ诱导突触前与突触后NMDA受体亚单位改变的时空差异性研究

Aβ synaptotoxicity is closely related to NMDA receptors(NMDARs) activity. NMDARs play an important role in both physiological synaptic plasticity and excitotoxic neuronal death. Classically, NMDARs were thought to be exclusively postsynaptic. However,in recent years, more and more evidences demonstrate that NMDARs also exist presynaptically and involve in the synaptic transmission and synaptic plasticity. Clarifying the different roles of pre- and postsynaptic NMDARs will be very important for understanding the modualtion of physiological function and helpful for directing the therapy of NMDARs related disorders. Based on the data got from the primary experiments, the purpose of our study is to demonstrating the spatial and temporal differences between alterations of pre- and postsynaptic NMDA receptor subunits induced by Aβ oligomer, by using combined approaches of rat hippocampal cell culture, slice and APP transgenic mouse with immuno-electron microscopy, whole-cell patch clamp recordings and 2-photon imaging of neuronal Ca(2+) signals. The main questions are focused on whether there are some spatial differences, and whether there are some temporal differences between alterations of pre- and postsynaptic NMDA receptor subunits induced by Aβ oligomer. This study is to investigate the cellular and molecular mechanisms of Aβ synaptotoxicity during the development of Alzheimer's disease, and will contribute to prevention and early therapy of Alzheimer's disease.

Aβ的突触毒性与NMDA受体关系密切，NMDA受体在神经突触可塑性与神经元兴奋性毒性损伤中均起关键作用。近年来的研究证实，NMDA受体不仅丰富表达于突触后膜，在突触前膜也有表达并有广泛功能。详细阐明突触前、后NMDA受体的功能及二者的差异性和相关性，对于正确理解NMDA受体如何调节突触发育等生理过程，以及有针对性的指导临床药物治疗NMDA受体相关疾病，具有十分重要而深远的意义。本项目基于课题组前期的研究成果，旨在以原代培养大鼠海马细胞、海马脑片及APP转基因小鼠为研究对象，结合免疫电镜、全细胞膜片钳、Ca2+信号检测等多种技术，探讨突触前、后NMDA受体亚单位改变的差异性，着重回答在Aβ毒性作用下，突触前、后NMDA受体亚单位表达变化存在哪些亚细胞水平空间分布上的差异；突触前、后NMDA受体亚单位的改变存在哪些时间上的差异等关键问题。为预防和确定AD早期治疗靶点提供相关的基础数据。

Aβ的突触毒性与NMDA受体关系密切，NMDA受体在神经元突触可塑性及兴奋性毒性损伤中具有重要作用。近年来研究发现，NMDA受体不仅存在于突触后膜，在突触前膜也有表达且可能具有广泛的未知功能。本研究以原代培养的海马细胞及APP/PS1小鼠等为研究对象，应用透射电镜、免疫电镜、免疫荧光、STORM 高分辨显微镜等检测方法，探讨了Aβ的突触毒性对于海马神经元突触前后结构及NMDA受体亚单位的作用，发现在不同年龄的APP/PS1模型鼠中以及原代海马细胞中，突触前后超微结构变化的差异及突触前后NMDA受体亚单位表达的不同，尤以NR2B亚单位变化更为显著,提示突触前后NR2B亚单位在Aβ早期突触毒性作用中具有不可忽视的重要作用。