MicroRNA(miRNA)是内源性的单链非编码小RNA，通过与靶基因mRNA的3'UTR结合，抑制其表达。miRNA被证实：通过调节基因表达来调控内皮细胞行为和血管发育。但是目前系统分析血管内皮细胞miRNA 表达谱的研究还很欠缺。我们利用流式细胞仪(FACs)从22小时Tg(fli1:EGFP)斑马鱼中分选出内皮细胞，另获得鸡和人内皮细胞。深度测序(deep sequencing)分析这些内皮细胞的miRNA表达，发现约40个在这些物种均有表达，在进化上保守。其中miR-146a和miR-10a/b不仅表达于斑马鱼、鸡和人类内皮细胞，而且在斑马鱼内皮细胞中的表达水平高于内皮细胞特异高表达的miR-126s，生物信息学分析显示它们可能调控一系列血管发育相关基因。此外预实验提示其中一个miRNA下调影响tip cell的形成。因此本项目拟研究它们在斑马鱼胚胎血管形成中的功能。

During vertebrate embryogenesis, the stereotyped pattern of the circulatory system is initially established by conserved genetic pathways. MicroRNAs (miRNAs) are single-stranded small none-coding RNAs, generally 19-25 nucleotides in length, that act as repressors of gene expression. It is evidenced that miRNAs regulate vascular development, but systematic analysis of miRNAs profile in endothelial cells (ECs) is thus far lacking. Lately, we took advantage of deep sequencing analysis to examine the miRNAs expression in arterial and venous ECs derived from human, chicken embryo, and zebrafish embryo. Around 40 common miRNAs were found to be conservatively presented in ECs of all the three species. Among the common group, the miR-146a and miR-10a/b are abundantly expressed. Furthermore, each expression level of the three miRNAs in zebrafish ECs is higher than that of the miR-126/miR-126b, which is recognized as endothelial specific miRNA. Bioinformatical analysis reveals that miR-146a and miR-10a/b potentially regulate several genes, involved in blood vessel development, including gng2, krit1, fli1b and mib, etc. In addition, our preliminary data show one of the miRNAs regulated the tip cell formation in branching intersegmental vessels. Up to date, there is no report to show the experimental evidence regarding the three miRNAs specifically involved in genetic pathways that control blood vessel development and zebrafish embryonic development. In current project, for the first time we suppose to investigate the roles of miR-146a and miR-10a/b in regulating zebrafish embryonic blood vessel formation. The outcome of this project will help understanding the full repertoire of action of miRNAs in vasculogenesis and angiogenesis and allow us to open a new avenue for target-designing drugs to control the formation of blood vessels in a variety of pathological conditions caused by insufficient or excessive blood supply.