国内外研究证实，miR-155在巨噬细胞中存在表达，而且高表达的miR-155可以抑制巨噬细胞向泡沫细胞的转化，进而抑制动脉粥样硬化的形成，但机制不详。我们通过研究发现，上调巨噬细胞中miR-155的表达能促进CEH的表达，同时伴有巨噬细胞泡沫化的降低。我们又通过生物信息软件发现，在Tim-3 3’-UTR存在miR-155的结合位点；在CEH基因的启动子区中含有Tim-3结合位点。因此，结合我们的前期研究结果提出如下假说：在巨噬细胞中过表达的miR-155可能是通过负性调控Tim-3的表达来实现上调CEH的表达；上调的CEH能够影响巨噬细胞的泡沫化过程，进而抑制AS的形成。本项目拟先验证miR-155与靶基因Tim-3的结合作用和位点；其次研究miR-155在巨噬细胞中是否是通过Tim-3来调控CEH的转录和表达，以及Tim-3对巨噬细胞活性的调节机制。该研究能够为AS的防治提供新途径。

Macrophages played a crucial role in the development of atherosclerosis, but the exact mechanism had not been clarified. The existence of microRNA-155 expression in macrophages had been demonstrated in our previous works, and high expression of microRNA-155 can inhibit the conversion of macrophages to foam cells. Meanwhile, it was found that the expression of CEH was changed when microRNA-155 in macropha- ges changed, thus affecting the formation of foam cells.On the basis of our previous researches, we proposed the following hypotheses: over-expressing microRNA-155 in macrophages may be through negative regulate the expression of Tim-3 to achieve up-regulated expression of CEH; up-regulation of CEH can affect the transformation of macrophages into foam cells, inhibiting the formation of AS. The project intended to firstly verify the microRNA-155 and the target genes of Tim-3 targeted binding and binding sites; then study microRNA-155 in macrophages regulating the transcription and expression of CEH through the Tim-3, and the regulatory mechanisms of Tim 3 on the activity of macrophage. The results of this project can not only reveal the specific mechanism of microRNA-155 controlling the expression of CEH in macrophages, but also provide a new targets and new ways for the atherosclerosis prevention to improve the therapeutic efficacy of atherosclerosis.

摘要 目的：miR-155可以通过干扰巨噬细胞向泡沫细胞的转化来抑制动脉粥样硬化的形成，但具体机制不是十分清楚。本研究我们主要观察miR-155对巨噬细胞中Tim-3和CEH等基因表达的影响，同时探讨了Tim-3在miR-155调节CEH等基因表达过程中的作用。方法: 培养人 THP-1 巨噬细胞，将miR-155 mimics、siRNA-CEH或Ad-Tim-3转染到 THP-1 巨噬细胞中，实时荧光定量 PCR 和 western blot 检测相关基因的表达；液体闪烁计数测定荷脂 THP-1 巨噬细胞内胆固醇流出情况，HPLC检测胞内脂质含量；油红O染色显示胞内脂滴情况。结果：转染 miR-155 mimics 的THP-1巨噬细胞中CEH的表达水平被明显上调，并呈剂量和时间依赖性，胞内胆固醇流出增加，胞内总胆固醇TC、胆固醇酯CE及游离胆固醇FC的含量明显减少，而转染siRNA-CEH则刚好出现相反的结果； Tim-3可以调控CEH的表达，两者呈反相关关系。高表达的Tim-3可以阻止miR-155增强CEH表达的作用。 结论： miR-155可以通过增强巨噬细胞内CEH信号通路的活性来抑制巨噬细胞向泡沫细胞的转化，但该作用很可能是通过抑制Tim-3的表达才得以实现。