ADDLs通过阻断ERK1／2与h3 Calponin的结合影响细胞质ERK1／2活化

Effects of ADDLs on the activation of cytosolic ERK1/2 via blockage of ERK1/2 binding to h3 Calponin

目的探讨ADDLs对细胞质p—ERK1／2的影响，揭示ADDLs影响突触可塑性导致认知功能障碍的分子机制。方法采用体外培养的大鼠海马神经元。免疫印迹方法观察ADDLs对p—ERK1／2的影响，细胞组分分离方法探索ADDLs影响ERK1／2在神经元各部位活化的规律；免疫共沉淀的方法检测ERK1／2与h3 Calponin的结合以及ADDLs对两者结合的影响。结果ADDLs以时间依赖的方式降低了神经元中p—ERK1／2水平；ADDLs对细胞质和细胞核部分ERK1／2的影响具有时序性，ADDLs作用1h显著降低细胞质中p—ERK1／2水平，作用6h细胞核中的p—ERK1／2才显著降低；免疫共沉淀结果显示ADDLs作用1h即可降低ERK1／2与h3Calponin的结合，而此时细胞核中P—CREB水平无显著变化。结论ADDLs作用早期首先通过阻断ERK1／2与h3Calponin的结合影响细胞质ERK1／2活化。

Objective To discuss the impact of ADDLs on the activation of cytosolic ERK1/2 and possible molecular mechanisms by which ADDLs affect synaptic plasticity, resulting in cognitive disorder. Methods The effects of ADDLs on phosphorylated ERK1/2 within primary hippocampal neurons were determined by immunoblotting. Subcellular fractions were isolated to further explore the effect of ADDLs on the levels of p - ERK1/2 within different parts of hippocampal neurons. The effect of ADDLs on ERK1/2 binding to h3 Calponin was detected by co - immunoprecipitation. Results ADDLs reduced the amounts of p - ERK1/2 in a dose - dependent manner, while different effects were observed on p -ERK1/2 localized within cytoplasmic and nuclear compartments as exposure times went. ADDLs could remarkably weaken the quantities of cytoplasmic p - ERK1/2 after 1 hour of treatment. In contrast, the levels of nuclear p - ERK1/2 were significantly declined after treatment for 6 hours. According to co - immunoprecipitation results, the binding of ERK1/2 to h3 Calponin was dissociated 1 hour after ADDL administration when no obvious changes were seen as to the quantities of p - CREB in the nucleus. Conclusion ADDLs can suppress the activation of cytosolic ERK1/2 via blockage of ERK1/2 binding to h3 Calponin in hippocampal neurons at an early stage.