周细胞GPR124信号介导缺血后脑微血管重建机制及调控研究

G-protein coupled receptors (GPCRs) have always been regarded as the principal target for the drug discovery. The molecular mechanism of neurovascular remodeling during pathological process of ischemic brain injury was far from articulate. In our recent study, the dramatic decline of GPR124 was observed in the ischemic cerebral microvessel. Importantly, GPR124 overexpression increased the microvessel density in ischemia areas. Therefore, the present study designed to address the precise role of pericyte GPR124 signaling on ischemia-induced neurovascular remodeling. Firstly, by using in vivo two-photon confocal microscope, we examine the spatiotemporal changes of pericytes behavior in the pathological process of subacute/chronic ischemic brain injury. Secondly, we further investigate the interrelationship between the pericyte GPR124 signaling and cerebral vascular remodeling. Thirdly, we examine whether GPR124 signal targeting could enhance the endogenous repair and finally contribute to preservation or restoration of ischemic brain. The data derived from the present study may provide a critical basis for development of recovery-enhancing therapeutic strategies during subacute/chronic poststroke neurovascular remodeling.

G蛋白偶联受体参与了广泛的生理与病理过程，是新药发现及研究的最重要靶点。脑微血管重建是缺血性脑损伤发生、发展及转归的重要病理过程，但其分子调控机制还远未阐明。我们前期利用激光共聚焦显微镜等技术检测发现脑缺血后小鼠脑微血管损伤并伴有周细胞GPR124表达明显下降，而慢病毒GPR124过表达可有效增加缺血后脑微血管密度。因此，在以往研究基础上，本项目以周细胞作为切入点开展深入探索：① 双光子共聚焦实时记录周细胞在缺血性脑损伤发生、发展及转归的病理过程中所起的时空动态变化规律；② 阐明脑缺血损伤后周细胞GPR124信号变化与缺血后脑微血管稳态及重建的内在关联性；③ 深入探究周细胞GPR124信号调控对改善脑缺血损伤后脑微血管稳态及神经功能恢复的影响。本课题的开展将深入揭示慢性缺血性脑损伤条件下周细胞与内皮细胞间的信号通讯模式及规律，为寻找防治脑卒中的治疗药物新靶点提供实验依据和研究思路。

脑微血管重构是缺血性脑损伤发生、发展及转归的重要病理过程， 因此对脑血管稳态维持及血管重构的分子机制的深入研究显得非常重要。本项目以周细胞G蛋白偶联受体（GPR124）信号通路为切入点，利用体内外脑缺血模型为研究平台，在细胞和整体水平开展了以下的研究：1)采用周细胞特异荧光标记的转基因小鼠和活体双光子激光扫描共聚焦示踪技术，揭示周细胞的迁移参与了脑缺血后微血管重构；2） in vivo 和 in vitro，采用基因过表达或缺失的方法阐明周细胞GPR124信号参与了周细胞的迁移；3）采用GPR124基因条件敲除小鼠结合碳素微栓（ME）脑缺血病理模型进一步分析周细胞GPR124对缺血后脑微血管重构的关联性。本项目以缺血后脑微血管周细胞为切入点，结合临床缺血后脑血管重塑疾病特点，阐明在脑缺血损伤后微血管重构分子事件中GPR124关联信号转导的调控规律，为缺血后脑血管重构紊乱源性机制提供了理论依据，为脑卒中防治提供了新的药物靶点。