miR-24的二级结构 - G-四链体对血管平滑肌细胞功能的调控

The phenotypic transformation, proliferation and migration （activation） of vascular smooth muscle cell are the important pathological basis of vascular injury. Accumulated studies have suggested that microRNAs play an important regulating role in the vascular smooth muscle cells activation. Current studies on the regulation of microRNA genes mainly involves their primary structure; However, the effects of their secondary structure changes on gene expression and function has not been reported yet. Our group recently found in the preliminary experiments that there is a non-classical secondary structure - G-quadruplex on miR-24. While other research group also found that abnormally high expression of miR-24 is closely related to the activation of vascular smooth muscle cells. On this basis, we hypothesized that stabilization of G-quadruplex can effectively reduce the abnormally high expression of microRNAs and inhibit the activation of vascular smooth muscle cell. Our project plans to use multidisciplinary research methods such as NMR(nuclear magnetic resonance), DSMB(dimethyl sulfate methylation blotting) and TALEN(transcription activator-like effector nucleases) technology to clarify that the function and mechanism of the formation and stabilization of G-quadruplex on the regulation of miR-24 at the vitro, cellular and animal levels, and explore the effects of pathological stimuli, which involved in the activation of vascular smooth muscle cells, on the formation and stabilization of G-quadruplex.

血管平滑肌细胞的表型转化、增殖和迁移（活化）是血管损伤的重要病理基础。大量研究表明微小RNA（microRNA，miR）在血管平滑肌细胞活化中发挥重要作用。目前microRNA调控机制的研究主要涉及基因一级结构，而关于其二级结构变化与基因表达和功能的关系未见报道。本课题组近期预实验发现miR-24上存在特殊二级结构—G-四链体，稳定该结构可以显著抑制miR-24的表达水平；而其他课题组发现miR-24的异常高表达与血管平滑肌细胞的活化密切相关。由此，我们提出稳定miR-24的G-四链体结构，下调异常高表达的microRNA，抑制血管平滑肌细胞活化的假说。本课题拟利用核磁共振，硫酸二甲酯甲基化印迹实验，TALEN技术等研究方法，在体外、细胞和整体水平阐明G-四链体的形成与稳定对miR-24及血管平滑肌细胞活化的作用，探讨血管平滑肌细胞活化的病理刺激因素对G-四链体形成和稳定的影响。

血管平滑肌的表型转化、增殖和迁移是血管损伤的重要病理基础。本项目目以内源性microRNA的调控机制研究为切入点，首次提出G-四链体结构的形成与稳定参与内源性microRNA表达水平的调控。并以此为线索筛选并发现了天然小分子药物粉防己碱通过稳定G-四链体调控miR-24表达，阐明G-四链体在血管损伤中的重要作用以及机制，拓展了基于G-四链体的血管损伤重塑防治研究新领域。