miR-150通过VEGF和Tie-2双重调控脑梗死后血管新生和血管渗漏

Promoting angiogenesis is one of the most promising treatment targets for stroke. The compensatory angiogenesis exist in infarct border zone after stroke, but the lumen of new blood vessels is badly closured, which leads to increase of vascular leakage. Mounting evidence demonstrates that a variety of signaling pathways regulate angiogenesis and vascular leakage, while two of those, VEGF/VEGFR2 and Ang-1/Tie-2 are most important. Using bioinformatic analysis, we have found that miR-150 can be the co-regulator of VEGF and Tie-2, and regulate angiogenesis and vascular leakage. In the present project, we will study the the role of miR-150 in cerebral angiogenesis and Promoting angiogenesis is one of the most promising treatment targets for stroke，however， the increase of vascular leakage is the other side of coin. Mounting evidence demonstrates that a variety of signaling pathways regulate angiogenesis and vascular leakage, while two of those, VEGF/VEGFR2 and Ang-1/Tie-2 are most important. Using bioinformatic analysis, we have found that miR-150 can be the co-regulator of VEGF and Tie-2, and regulate angiogenesis and vascular leakage. In the present project, we will study the role of miR-150 in cerebral angiogenesis and vascular leakage after stroke with siRNA, WB, PCR, confocal immunofluorescence, dual luciferase reporter assay and other molecular biology techniques, and in vivo MRI and other methods. Firstly, we will explore the spatio-temporal dynamics of miR-150, and detect the effect of miR-150 on controlling both cerebral angiogenesis and vascular leakage after stroke. Secondly, we will verify the regulation of miR-150 in the two signaling pathways, VEGF/VEGFR2 and Ang-1/Tie-2 after cerebral stroke. Thirdly, we will also try to confirm that miR-150 can control cerebral angiogenesis and vascular leakage after stroke via VEGF/VEGFR2 and Ang-1/Tie-2 signaling pathways with the interventions of the key molecules, such as miR-150, VEGF, Ang-1 and Tie-2. Our project will demonstrate whether and how miR-150 controls cerebral angiogenesis and vascular leakage, and provide a potential therapeutic target to promote angiogenesis after stroke.

血管新生是脑梗死最有前途的治疗策略之一，但存在增加血管渗漏的问题。VEGF/VEGFR2和Ang-1/Tie-2信号途径在血管新生和渗漏的调控中十分重要。我们前期研究通过生物信息学技术发现miR-150可能是VEGF和Tie-2的共同调节因子，可双重调节血管新生和渗漏。本项目拟在in vivo和in vitro情况下，采用siRNA、WB、PCR、免疫荧光共聚焦、双荧光素酶报告系统等分子生物学及活体MRI成像技术，进一步探讨脑梗死后miR-150的时空变化规律及其对血管新生和渗漏的影响；明确miR-150对脑梗死后VEGF和Tie-2及下游分子的同步调控作用；通过对其关键分子的干预，明确VEGF和Tie-2是否介导miR-150双重调控血管新生及渗漏。本项目拟阐明miR-150是否可通过VEGF和Tie-2双重调控血管新生和渗漏，从而为脑梗死后有效血管新生提供潜在的理想靶点。

脑梗死是国内外死亡率致死率致残率最高的疾病之一。血管新生是脑梗死后最有前途的治疗策略之一，但存在增加脑梗死后血管渗漏的问题。如何平衡脑梗死后血管新生和渗漏具有十分重要的意义。本项目探讨了miR-150在脑梗死后脑组织、血液、主要血脑屏障构成细胞的表达；并在动物模型（MCAO）及细胞模型（OGD）中研究了miR-150对血管新生和血管渗漏的双重调控作用。结果发现脑梗死后miR-150在脑组织、血清表达明显下降，在星形胶质细胞、神经细胞、脑微血管内皮细胞中表达也明显下降，miR-150下调可促进脑微血管内皮细胞的增殖、迁移和管腔形成，在MCAO模型可显著增加脑梗死周边区新生血管数目；而且miR-150下调可减少脑梗死后脑微血管内皮细胞的凋亡，促进其存活，增加紧密连接蛋白的表达，保护脑梗死后血脑屏障，减轻血管渗漏，脑水肿，而上调miR-150的功能则对血管新生和血管渗漏有相反的结果，最终在MCAO模型中，经活体影像学研究发现下调miR-150可以减少脑梗死的面积，减轻脑水肿促进脑梗死后神经功能的修复。进一步的研究证实miR-150对血管内皮生长因子(VEGF)和血管生成素受体酪氨酸激酶受体-2(Tie-2)的直接调控介导了miR-150对血管新生和血脑屏障的保护作用。本研究提示miR-150可作为脑梗死后预后判断的潜在分子标志物和潜在的治疗靶点。