环状RNA-circDRAM1通过竞争性结合miR-218调控MeCP2促进内皮祖细胞衰老的机制研究

内皮祖细胞（EPC）衰老是血管衰老的主要始发因素，但环状RNA在其中的作用尚不明确。申请人既往研究显示MeCP2是促进EPC衰老的关键蛋白，进一步预实验发现：衰老EPC中circDRAM1表达水平明显升高；过表达circDRAM1促进EPC衰老并海绵吸附miR-218；miR-218抑制EPC衰老并靶向降低MeCP2。由此提出假设：circDRAM1通过竞争性内源RNA机制抑制miR-218，引起下游靶基因MeCP2表达增加，导致EPC衰老。本项目拟：1）构建人EPC复制性和应激性衰老模型，通过腺病毒载体转染观察circDRAM1表达变化及对EPC衰老的影响，2）采用荧光原位杂交、RNA免疫共沉淀、荧光素酶检测探讨circDRAM1促进EPC衰老的分子机制，3）利用衰老干预因子和自然衰老大鼠模型在体内外验证circDRAM1对EPC和血管衰老的作用，为血管衰老性疾病的防治提供新的干预靶点。

Senescence of endothelial progenitor cells (EPC) is a crucial initiative factor in vascular aging. Circular RNA is involved in the post-transcription of microRNA on the target gene as a competitive endogenous RNA, but there are no reports of its effects on EPC senescence. We found in preliminary experiments: ①the expression of circDRAM1 in senescent EPC is significantly increased while the expression of miR-218 is decreased. ②overexpression of circDRAM1 promotes EPC senescence and significantly reduces miR-218 level. ③miR-218 inhibits EPC senescence and targetedly suppresses MeCP2 expression. Accordingly, we propose the hypothesis that circDRAM1 inhibits the binding of miR-218 to MeCP2 mRNA 3'UTR by competing with miR-218, regulates the expression of MeCP2 protein, and mediates EPC senescence. This project is intended to clarify the role and molecular mechanism of circDRAM1 in EPC senescence both in vitro and in vivo, using the methods of fluorescence in situ hybridization, adenoviral vector transfection, RNA immunoprecipitation, and Luciferase reporter assays. The study will provide a new strategy for the prevention and treatment of age-related vascular diseases.