miR-211通过NR2B致注意缺陷多动障碍学习记忆损伤的机制研究

ADHD is always accompanied by learning and memory impairment and its mechanism is still unknown. miR-211 is a significantly up-regulated miRNA expressed in the hippocampus of SHR, an animal model of ADHD, compared with WKY by microarray. Over-expression miR-211 impaired the learning and memory abilities of WKY. Bioinformatics prediction and luciferase reporter system confirmed NR2B as its target genes, which was decreased in SHR compared with WKY. NR2B plays an important role in synaptic plasticity and learning and memory,which means miR-211 could lead to learning and memory impairment through decreasing NR2B.This study is to observe LTP, synaptic morphology and NR2B expression changes after miR-211 overexpression or silencing in the primary cultured hippocampal neurons; further with the NR2B gene overexpression or silencing, the NR2B mechanism of miR-211 on synaptic plasticity will be investigated; to observe learning and memory abilities and NR2B expression changes after miR-211 overexpression or silencing in WKY or SHR. The role of miR-211 on synaptic plasticity has not been reported, and the results will help us to clarify the regulatory mechanism of synaptic plasticity and provide a potential target to improve learning and memory in ADHD.

儿童注意缺陷多动障碍（ADHD）常伴学习记忆损伤，但机制未明。miR-211是我们应用芯片筛选到的、在ADHD动物模型SHR大鼠海马中表达较对照WKY大鼠显著上调的差异miRNA。已发现，海马过表达miR-211的WKY大鼠学习记忆损伤；软件预测及萤光素酶报告实验证实NR2B为其靶基因；而SHR大鼠海马NR2B表达显著低于WKY大鼠。NR2B是在突触可塑性及学习记忆中发挥作用的功能基因，因此提出miR-211通过调节NR2B致ADHD学习记忆障碍的机制。拟通过：观察miR-211过表达/表达沉默对原代海马神经元细胞NR2B及突触可塑性的影响；以NR2B为机制，分析miR-211与NR2B相互关系，论证miR-211影响学习记忆的调控机制；并通过在体动物实验加以验证。miR-211与学习记忆的关系未见报道，课题将阐明 miR-211致ADHD学习记忆障碍的机制，为ADHD治疗提供潜在靶标。

儿童注意缺陷多动障碍（ADHD）常伴学习记忆损伤，但机制未明。海马是研究学习记忆最重要的脑区，通过对ADHD动物模型SHR/WKY大鼠海马脑区芯片的筛选及验证，我们最终确定了其中差异表达显著、高度保守并高表达于脑组织的miR-211作为研究对象。目前，miR-211与学习记忆的关系未见报道。本研究从体外细胞水平、体内动物水平及分子机制三个方面，系统阐述了miR-211与ADHD学习记忆损伤之间可能存在的密切联系。研究发现，①miR-211 过表达后原代培养的海马神经元细胞突触数目增加，网络结构致密，miR-211 抑制后神经突触数目减少，网络结构松散，呈现空泡样；②在体水平，miR-211 过表达后SHR大鼠在经典学习记忆行为学实验中表现出学习记忆能力的增强，miR-211 抑制后SHR大鼠则表现出学习记忆能力的下降，同时伴随海马组织结构的改变，提示，miR-211可能通过影响突触超微结构，从而参与ADHD的学习记忆损伤。③进一步研究其中的机制，发现miR-211明确作用于靶基因DYRK1A，且动物模型SHR/WKY海马组织中的DYRK1A呈现差异表达，而miR-211 过表达/抑制后同样可以引起SHR大鼠海马组织中DYRK1A表达的改变。因此，高度提示miR-211可能通过DYRK1A参与突触超微结构的改变，从而参与到ADHD学习记忆损伤的机制中，为ADHD治疗提供潜在靶标。