IL-17A与fractalkine/CX3CR1通路互调控促进缺血性脑卒中恢复期NVU重建机制研究

Neurovascular unit (NVU) reconstruction plays key roles in the functional recovery after ischemic stroke (IS). The fractalkine/CX3CR1 signaling pathway mediates the interaction between neuron and microglia. Recent clinical research has shown that the fractalkine/CX3CR1 signaling pathway is associated with the functional recovery after ischemic stroke. Our recent data showed for the first time that astrocytic IL-17A could promote neurogenesis and functional recovery in the later phases of stroke recovery. Our preliminary results showed that delayed administration of IL-17A significantly increased the expression of fractalkine in neurons in vitro. According to these findings, combined with recent findings that CX3CR1 can modulates the production and secretion of IL-17A in neurodegenerative diseases, we hypothesize that the bidirectional regulation of IL-17A and fractalkine/CX3CR1 signaling could promote the reconstruction of NVU in the recovery phase of stroke through mediating the coordinate interaction between neurons, microglias and astrocytes. This project intends to establish a mouse model of IS and analyse the data using different techniques including immunoblotting, immunofluorescence, RT-PCR and patch clamp to investigate whether the coordinate interaction between IL-17A and fractalkine/CX3CR1 signaling exsits during stroke recovery. This project can provide new therapeutic strategies for the treatment of IS in the recovery phase of ischemic stroke.

神经血管单元（NVU）重建是决定缺血性脑卒中（IS）功能恢复最重要因素。 Fractalkine/CX3CR1是介导NVU中神经元与小胶质细胞相互作用的重要通路，且近期临床试验证实其与IS功能恢复密切相关。本课题组首次发现IS慢性恢复期星形胶质细胞分泌的IL-17A可促进神经功能恢复，体外实验IL-17A可上调神经元fractalkine表达。结合新近报道CX3CR1在神经退行性疾病等模型中可调节IL-17A分泌，我们提出假说：IS慢性恢复期IL-17A与fractalkine/CX3CR1通路双向调控可协调神经元、小胶质细胞和星形胶质细胞的相互作用而促进NVU重建。本项目拟建立小鼠IS模型，采用免疫印迹，免疫荧光，RT-PCR，膜片钳等技术研究IS恢复期IL-17A与fractalkine/CX3CR1通路是否存在双向调节环路并探讨其对NVU重建的影响，以期为IS恢复期治疗提供新策略。

我们既往研究发现缺血性脑中风（ischemic stroke，IS）的慢性恢复期，星形胶质细胞分泌IL-17A可促进脑室下区神经祖细胞再生和功能恢复。本课题在IS慢性恢复期，通过干预IL-17A信号刺激神经血管单元（NVU）的重建；同时药理学干预CX3CL1信号或者基因敲除CX3CR1信号，探究IL-17A是否依赖CX3CL1/CX3CR1信号促进IS慢性恢复期神经血管单元的重建以及神经功能的恢复。通过体内、外实验结果显示：1）外源性抑制CX3CL1信号或者基因敲除CX3CR1信号，均能够抑制IS慢性恢复期神经功能恢复和神经再生；而且外源性给予重组CX3CL1蛋白，能够促进神经功能恢复和神经再生。2）IL-17A是依赖CX3CL1/CX3CR1信号，促进IS慢性恢复期神经和血管再生。3）生理性锻炼通过CX3CL1/CX3CR1信号作用，有效促进NVU重建和神经功能恢复。结论：IS慢性恢复期，CX3CL1/CX3CR1信号轴是调控神经血管单元重建和神经功能恢复的关键信号通路。