FE65对海马突触可塑性和学习记忆调控作用的细胞分子机制研究

As a multimodular adapter protein, FE65 possesses protein-protein interacting domains to connect several proteins such as amyloid precursor protein (APP), Notch and LRP together to form a protein complex network. FE65 is highly expressed in brain and has been found playing an important role in the regulation of Aβ production, so FE65 is a protein related to the onset of Alzheimer's disease (AD). In our previous study, knockout of FE65 gene caused the impairment of learning and memory, and the impairment of hippocampal NMDA receptor-dependent LTP, but the underlying mechanisms remain unclear. In this proposal, we will try to reveal how FE65 regulates hippocampal synaptic plasticity and learning and memory by using neuro-electrophysiological, neuropharmacological, behavioral, molecular, and biochemical experimental protocols. We will focus on how FE65 regulates hippocampal LTP, LTD and depotentiation in adult mice, and the relationships between NMDA receptor, FE65 and APP in the regulation of synaptic plasticity. We will also try to reveal their related signaling pathways (e.g. APP, Notch) in the regulation of synaptic plasticity. Based on these findings, we will try to adjust the expression level of FE65 in hippocampus to finally delay or even prevent the impairment of synaptic plasticity and the disorder of learning and memory in APP/PS1 double mutant mice, which is an animal model of AD. Hopefully, these research results will accelerate the process in promoting FE65 to become a potentially effective target of gene engineering drugs for the treatment of AD, and also provide theoretical and experimental support for the action mechanisms of FE65 in the AD treatment.

FE65是一个与Aβ前体蛋白（APP）具有相互作用的多分子链接蛋白，在脑内高度表达，参与调节Aβ的生成，与阿尔茨海默症（AD）的发病有关。我们前期研究发现，FE65基因敲除造成小鼠学习记忆和海马NMDA受体依赖型LTP的损伤，其机理不明。本项目在前期工作基础上，采用神经电生理、神经药理、行为和分子生化等多种方法，着重研究NMDA受体、FE65和APP在海马突触可塑性（LTP、LTD和Depotentiation）及学习记忆调控中的相互作用关系，力图系统地揭示FE65调节APP和Notch信号转导通路的分子机制，以及对海马突触可塑性和学习记忆的调控机制。在分子机制研究基础上，通过调节FE65的表达水平来延缓或阻止APP/PS1双基因突变AD模型小鼠的突触可塑性和学习记忆损伤。本项目研究有望促使FE65尽早成为有效防治AD的潜在基因工程药物靶点，为FE65的作用机制提供可靠的理论和实验依据。

FE65 是一个与Aβ前体蛋白（APP）相互作用的多分子链接蛋白，参与调控Aβ的生成，与阿尔茨海默症（AD）的发病有关。本项目探讨了FE65对成年小鼠海马突触可塑性和学习记忆的调控作用及其细胞分子机制，通过相关药物延缓或阻止AD模型小鼠的突触可塑性损伤和学习记忆障碍。目前主要完成了以下研究内容：1）探讨了p97FE65 调控小鼠海马NMDA受体依赖型LTP的细胞分子机制，实验结果说明p97FE65基因敲除损伤海马NMDA受体依赖型LTP与海马神经元胞内NMDA受体-ERK信号转导通路异常有关；2）对p97FE65蛋白的上游信号分子Aβ引起的海马LTP损伤机制进行了研究，发现Aβ过度激活线粒体凋亡蛋白BAX和caspase-3，钙通道抑制剂2-APB可以有效阻断Aβ造成的海马LTP损伤，阻止BAX-caspase-3-GSK3-β凋亡信号转导通路的激活；3）研究了磷酸二酯酶PDE4 的抑制剂Rolipram如何影响野生型小鼠在Morris水迷宫作业中的长时记忆更新和空间工作记忆，发现Rolipram可以改善C57BL/6小鼠在反转平台学习中的记忆提取，加快小鼠对初始平台长时记忆的消退，但明显损伤小鼠在水迷宫中的空间工作记忆，为今后采用Rolipram改善FE65相关学习记忆障碍提供依据。这些研究结果有助于人们加深对阿尔茨海默症病理机制的认识，寻找有效的药物作用靶点。