GluA1乙酰化修饰介导突触可塑性在PS子代抑郁样行为的机制

Prenatal stress (PS) can cause depression of the offspring, however, its mechanism is unclear and have many problems in clinical drugs. More than 10 years ago, we put forward and found PS offspring depression-like behavior related with glutamate abnormal metabolism , but still face challenges in offspring with characteristics of scattered onset and recurrence. Our preliminary data indicated that PS leaded to the decrease of GluA1 mRNA and protein expression, subunit of AMPARs in offspring rats , and TSA, a deacetylase inhibitor, could increase the expression of GluA1 and improve depression-like behavior of offspring. The results suggested that acetylation modification of GluA1 may be a potential drug target of depression-like behavior in PS offspring. Moreover, our data also indicated that depression-like behavior with the changes of dendritic spines and SYN of synaptic plasticity in PS offspring. The project firstly proposes that the depression-like behavior in PS offspring was resulted from synaptic plasticity mediated by hippocampus GluA1 acetylation. We explore the receptor path and molecular mechanisms of pathological development of depression mediated from synaptic plasticity with alteration of GluA1 acetylation by electrophysiology, morphology, behavioral and molecular biological tests etc.. The research results will uncover further pathological mechanism of depression and provide evidence of new potential target in depression therapy .

产前应激（PS）可引起子代抑郁，其机制不清，现有临床用药面临诸多问题。10余年前，我们提出并发现PS子代抑郁与谷氨酸代谢异常有关，但仍面临子代散在发病，反复发作等特点的挑战。前期我们研究发现PS导致子代大鼠海马AMPARs 亚基GluA1 mRNA和蛋白表达减少，去乙酰化酶抑制剂TSA，增加GluA1的表达，并改善子代抑郁样行为。结果提示GluA1乙酰化修饰可能是抗PS子代大鼠抑郁潜在药物靶点；还发现抑郁样行为的发生伴有树突棘、SYN等突触可塑性的改变。本研究首次提出海马GluA1乙酰化修饰介导突触可塑性改变，导致PS子代抑郁样行为。拟用行为学、形态学、电生理学、分子生物学等方法，探讨GluA1乙酰化修饰介导突触可塑性改变，引起子代抑郁发生发展过程中受体途径及相关分子机制，研究结果将为深入研究抑郁病理机制和发掘药物作用新靶点提供证据。

有研究发现产前应激（PS）会引起子代情感障碍，出生后给予交叉喂养，发现子代的行为异常得以改变，推测PS导致子代抑郁样行为改变可能与表观遗传有关。而乙酰化是最常见的表观遗传类型之一。AMPARs（α-氨基-3-羟基-5-甲基-4-异恶唑丙酸受体）是重要离子型谷氨酸受体，同时也是介导中枢兴奋突触后电流的主要成分，近来多项研究也证实抑郁与AMPARs（GluA1-4）有关。.本研究探讨GluA1乙酰化在PS子代抑郁样行为中的作用机制。首先建立产前应激大鼠模型，然后海马区微注射AMPA、AMPA受体拮抗剂NBQX，去乙酰化酶抑制剂trichostatin A等，通过糖水偏好实验观察海马乙酰化对子代大鼠抑郁样行为的影响，然后通过RT-PCR和western blot观察子代大鼠海马AMPA各亚基表达的变化；利用ChIP-qPCR观察AMPA各亚基中H3K9的影响。.结果：（1）PS子代大鼠的糖水偏好度明显低于对照组，出现快感缺乏，表现为抑郁样症状。.（2）注射AMPA后可明显改善子代大鼠的抑郁样行为，而NBQX则加重了子代的抑郁样行为，证实PS子代的抑郁样行为与AMPAR有关；PS子代大鼠海马AMPARs的GluA1、GluA2和GluA3亚基mRNA在海马CA1区的表达与对照组相比，明显减少；而使用TSA后，可明显改善PS导致的GluA1-3亚基mRNA的表达。.（3）在ChIP-qPCR实验中发现，PS可明显抑制GluA1-3 H3K9的乙酰化水平，TSA可明显增强PS诱导的其水平的降低，而GluA4 H3K9水平未发现明显变化。同样在Western Blot中也发现TSA可明显逆转PS引起的GluA1-3亚基蛋白表达的减少，使其表达明显提高；AMPARs的GluA4蛋白的表达在各组中均无明显差异。.（4）我们还发现PS可抑制突触可塑性标志物PSD95的表达，而TSA则提高表达，初步证明TSA改善PS子代抑郁样行为可能与通过提高AMPARs的表达而改善突触可塑性有关。.本研究结果证实海马区乙酰化可以改善PS子代大鼠的抑郁样行为，这种作用可能是通过增强AMPARs表达实现，其中Glu1-3 H3K9乙酰化水平起关键作用。