Pannexin 1调控PI3K/Akt信号在脑梗死后神经可塑性中的作用

Pannexin 1 constitutes part of the channel complex on postsynaptic membrane, and essential in regulating the neural plasticity in the cortical peri-infarct area after cerebral infarction, and its molecular mechanism remains to be elucidated. Based on experiments reported in literature, at astrocytes activation of the PI3K/Akt signaling pathway mediates axonal and spine regeneration of cortical neurons after OGD through GSK-3β signaling pathway, participating in neurol plasticity. Our group has confirmed that inhibition of Pannexin 1 regulated dendritic spine density and promoted neural functional recovery after cerebral infarction. At the same time, in our preliminary experiment, using pannexin 1 knockout mice to culture cortical neurons in both normal and hypoxia conditions(OGD), we discovered the expression of pAkt was significantly decreased. Furthermore, our other preliminary experiment observed that inhibition of PI3K can increase dendritic spine density of cortical neurons after OGD. So our hypothesis is that Pannexin 1 activate PI3K/Akt signal and regulate axonal and spine plasticity, this maybe a novel mechanism of neural plasticity regulation after cerebral infarction. This research subject plan to use pannexin 1 knockout and wildtype mice with MCAO, and cultured cortical neuron and brain slice with OGD to prove our hypothesis at the level of the whole body and cellular. The principal methods conclude immunohistochemistry, Western Blot, RT-PCR,and electrophysiology etc. The blocking agent and agonists will be used to upregulate or inhibit PI3K/Akt, and ethology, morphology, expression of GSK-3β and Arp3 also be observed. The research will provides a novel approach and target for neural plasticity therapeutic intervention after cerebral infarction.

Pannexin 1是构成突触后膜通道复合体的主要成分之一，在脑梗死后神经可塑性中起重要作用，其具体分子机制有待阐明。文献提示，星形胶质细胞PI3K/Akt信号通路联合下游GSK-3β蛋白调控缺氧后轴突及树突棘生长，参与调节神经可塑性。本课题组已证实Pannexin 1可调节神经元树突棘生长并促进大鼠脑梗死后神经功能的恢复，同时预实验OGD处理Pannexin 1基因敲除小鼠培养神经元，发现pAkt表达明显降低，进一步抑制PI3K可增加OGD神经元树突棘密度。因此，我们提出“Pannexin 1激活PI3K/Akt信号调节轴突和树突棘可塑性”可能是脑梗死后神经可塑性调节的新机制。本实验拟使用Pannexin 1基因敲除小鼠建立MCAO动物模型及OGD细胞模型，通过激动剂和阻滞剂上调/下调PI3K/Akt活性，观察小鼠行为学、形态学、分子生物学及电生理变化，从整体—细胞水平证明我们的理论。

本课题使用Pannexin 1基因敲除小鼠建立MCAO动物模型及OGD细胞模型，通过激动剂和阻滞剂上调/下调PI3K/Akt活性，观察小鼠行为学、形态学、分子生物学等指标，完成研究目标：Pannexin 1 对PI3K/Akt/GSK-3β信号通路的影响，及其与脑梗死后神经病理生理机制。取得的主要研究结果及意义：脑缺血引起神经元Pannexin 1活性增强，引起PI3K/Akt信号通路激活，继而调节GSK-3β、HDAC9等指标的变化，这是脑梗死后病变炎性机制之一。Pannexin 1有可能成为下一个治疗脑梗死，或者减轻脑损伤的靶点。