脑卒中Cofilin rod生成导致缺血半暗带神经元功能损伤的机制及其干预靶点研究

Cognitive dysfunction is one of the long-term complications in majority patients suffer with ischemic stroke, and neuron protection after ischemic stroke is important for the functional recovery in clinic. However, the mechanisms underlying the functional damage of the survival neurons after the ischemic stroke remain unclear. Cofilin, a cytoskeletal actin modulator, could form rod structure along with the actin (called cofilin rod) under certain abnormal condition such as glutamate excitotoxic stimulation. Long has been known that ischemic stroke induces large amount of glutamate accumulation in brain regions. Our previous studies have demonstrated that cofilin rods are formed in dendritic area under glutamate stimulation, and then they block intracellular trafficking and induce loss of synapse and impairment of synaptic function. Therefore, we hypothesis that excitotoxic glutamate stimulation during ischemic stroke induces cofilin to form rod structures which in turn triggering the loss of synapse and the impairment of synaptic transmission and plasticity, and further affect the cognitive function. By applying immunohistochmistry and electrophysiological techniques in MCAO rat model and ODG cell model, we tend to reveal: 1) whether ischemic stroke will trigger the cofilin to form rods in ischemic brain region, and their distribution pattern, 2) what is the molecular bases of the cofilin to form the rod structure, 3) whether the ischemic stimulation induced cofilin rods causes synaptic dysfunction of the neurons within the affected brain region and its underline mechanism, 4) what is the modulatory role of LIMK-SSH on the cofilin function and the rod formation under ischemic stimulation, and the possible role of LIMK-SSH-cofilin pathway in intervention of the neuronal damage after ischeminc stroke. From this study, we try to reveal a new mechanism underline ischemic stroke related neuronal damage and consequently cognitive dysfunction and provide new theory for neuron protection after ischemic stroke.

缺血半暗带神经元保护是缺血性脑卒中患者预后的重要措施，但缺血再灌注对神经元的形态功能损伤机制目前仍不清楚。我们前期发现肌动蛋白调控蛋白cofilin异常形成栓状结构（rod）后，阻碍胞浆运输，引起神经元突触丢失和功能受损，而谷氨酸兴奋毒性是导致Rod形成的重要诱因之一。虽然缺血性脑卒中后的早期病理变化包括谷氨酸的大量释放，但是否引起rod生成及其在神经元功能损伤中的作用至今没有研究报道。本项目拟在大鼠中动脉栓塞再灌注和培养神经元糖氧剥夺模型上，阐述缺血再灌注后1）脑内Rod形成的时空分布规律，2）rod生成的分子位点异常机制及其调控，3）缺血诱导形成rod损伤神经元形态功能的作用机制，4）Cofilin调控蛋白LIMK-SSH干预rod生成对缺血后神经元功能保护的作用及机制。项目完成将阐明Cofilin功能异常与缺血性脑卒中后神经元功能损伤关系的新机制，为保护神经元功能提供有效干预新途径