MicroRNAs与组蛋白去乙酰化酶HDACs共同调控脑卒中后缺血区脑组织血管新生的分子机制

Ischemic stroke can induce angiogenesis in the ischemic area, and the density of new blood vessels is closely related to the prognosis of patients. Promoting angiogenesis effectively is essential to the recovery of stroke and other ischemic diseases. Our preliminary studies indicate that miRNA210 participates in angiogenesis process through HIF-VEGF-Notch pathway. We also found that expressions of miRNA222 and miRNA92a, which were closely related to angiogenesis, changed significantly after stroke. Simultaneously, expressions of a variety of HDACs changed distinctly, too. Combine our data with recent studies about complex and mutual relationships between histone modification and miRNA, we proposed that histone acetylation could cooperate with miRNA in modulating angiogenesis after stroke. This project intends to find out the key miRNAs and HDACs in angiogenesis after stroke through Solexa high-throughput sequencing, MS analysis and genechip, and verify their mutual regulation relationships and important regulation steps. The purpose of this research is to preliminarily clarify the new mechanisms based on the modulation network mainly composed of miRNA and histone modification in angiogenesis after stroke, and provide new scientific evidence for new targets of brain stroke treatment.

脑卒中可诱发缺血区的血管新生，新生血管的密度与患者的预后密切相关。因此，有效促进新生血管的形成对于脑卒中等缺血性疾病的恢复至关重要。课题组前期研究发现miRNA210参与了缺氧/ HIF-VEGF-Notch信号通路调控脑缺血后血管新生过程，同时还发现脑缺血后，与血管生成密切相关的miRNA222、92a等表达水平均出现明显变化并伴随多种组蛋白乙酰化酶HDACs的表达变化。结合组蛋白修饰与miRNA存在相互调控关系的最新研究报道，我们推测极有可能是组蛋白乙酰化与miRNA共同参与了脑缺血后血管新生的调控。本课题通过Solexa高通量测序、质谱分析及基因芯片等技术筛选调控脑缺血后血管新生的关键miRNAs和HDACs，并对二者之间相互调控的关系及调控环节进行研究验证，以期阐明miRNAs与组蛋白修饰为主构成的表观遗传调控网络调控脑卒中后血管新生的新机制，为脑卒中的修复治疗提供新的科学依据。

利用高通量测序从全基因组学角度理解脑缺血后的病理生理机制有助于为脑缺血治疗提供新思路。近期的研究表明，HDACs和非编码RNA等参与调控脑卒中的病理生理过程，但其对脑缺血后缺血区微血管新生的作用及调控途径尚有待进一步明确。本项目利用大鼠脑缺血模型及血管内皮细胞体外缺氧模型，通过高通量测序、生物信息学分析、荧光定量PCR、northern blot、western blot和过表达等研究手段系统的探讨脑缺血后HDACs和tRNAs的功能及可能的调控机制。结果表明脑组织缺血缺氧诱导HDAC4蛋白磷酸化，介导激活HIF-VEGF信号途径调控血管内皮细胞的增殖、迁移及成管等功能进而调控血管新生的生物学过程；此外，我们的研究结果显示tRNAs参与了脑缺血后血管新生的过程，过表达tRNAVal和 tRNAGly来源的小片段RNA抑制血管内皮细胞的增殖、迁移和成管功能。本项目首次对脑缺血后HDACs和tRNAs的功能及机制进行深入探讨，这些研究成果有助于对脑缺血后血管新生调控机制的全面、深入的理解，并为治疗性血管新生措施寻找新的治疗靶点提供理论依据。