miR-145调控自噬相关基因对动脉粥样硬化斑块稳定性的作用

Autophagy is an important determinant for atherosclerotic plaque stability. It is significant to elucidate the regulatory mechanism of autophagy and to maintain the basal or moderate autophagy in the plaque. The investigations of regulation of miRNAs on autophagy have been emphasized, but there is still no report about autophagy regulated by miRNAs in the AS plaque. MiR-145 is increased in symptomatic plaques significantly, and it can improve the plaque stability by the phenotype turnover of VSMCs. The applicant found that the target genes of miR-145 included multiple genes related to the progression of AS, and some of them were involved in autophagy. The preliminary experiments results showed that miR-145 was increased in response to ox-LDL, and it inhibited the autophagy induced by ox-LDL. In this project, we will determine the expression patterns of miR-145 in AS lesion, then detect the changes of autophagy and plaque stability in antagomiR-145/apoE-/- mice. The autophagy-related genes will be screened via autophagy PCR array and then be verified. Finally, the hypothesis presented in this project-miR-145 can inhibit the excessive autophagy in the AS plaque to maintain the plaque stability, will be demonstrated, which will supply the novel ideas and investigative clues for the prevention of AS.

细胞自噬是AS斑块稳定性的一个重要决定因素，研究其调控机制，维持适度的自噬水平，对于斑块稳定性有重要意义。miRNAs调控细胞自噬的研究越来越受到重视，而miRNAs是否调控AS斑块中细胞自噬目前未见报道。miR-145在有症状颈动脉粥样斑块中表达显著升高，它能够决定SMCs向收缩表型转化而维持斑块稳定性。申请者发现miR-145的靶基因包含多个与AS进程密切相关的基因，有些靶基因与自噬发生有关；预实验初步发现miR-145在ox-LDL刺激下表达明显升高并能够抑制ox-LDL诱导的细胞自噬。本项目首先检测miR-145在AS病变的表达模式；再检测antagomiR-145/apoE-/-小鼠AS斑块自噬与稳定性变化，采用基因芯片筛选并验证受调控的自噬相关基因。证实"miR-145能够抑制斑块内细胞过度自噬从而维持AS斑块稳定性"这一实验假说，为AS疾病的防治提供新的思路与实验线索。

本项目旨在探讨miR-145调控细胞自噬相关基因在动脉粥样硬化斑块稳定性中的作用，为AS斑块稳定性研究提供新的实验线索与思路。研究结果发现：1）miR-145在急性心肌梗死病人血浆中水平增高，且增高程度与病人心电图ST段抬高呈正相关，miR-145可能成为冠心病分型的重要指标；2）miR-145在三种AS主要细胞中ox-LDL刺激下表达均升高；而miR-145过表达的VSMCs自噬标志分子LC3II表达减少而 p62表达水平增多，miR-145内源性抑制的VSMCs则LC3II表达增多而p62水平降低；3）RNA双测序找到215个表达上调、291个表达下调的差异表达转录本，取差异表达lncRNA靶基因与差异表达mRNA基因交集，发现256个靶基因；其中TGFBR2是miR-145调控自噬的关键靶基因。以上研究结果表明，miR-145能够调控细胞自噬从而影响动脉粥样硬化斑块的稳定性。项目研究期间，培养博士研究生1名，硕士研究生1名（已毕业），参与编写专著1部，申请国家发明专利1项，以通讯作者或第一作者已发表SCI学术论文3篇，另有1篇英文论文正在投稿，1篇英文论文正在撰写（标注受本项目资助）。.