血管平滑肌细胞表型相关lncRNA的筛查及其在转录调控中与核内microRNA的互作效应

In human and mammalian cells, the long non-coding RNAs (lncRNAs) play very important roles in gene transcriptional regulation, but so far, the study of cardiovascular lncRNAs has just started. The major researches of present about the regulation mechanism of microRNAs (miRNAs) just concern on the post-transcriptional regulation of miRNAs-mRNAs interactions in the cytoplasm, and the study about mechanism of nuclear miRNAs involved in transcriptional regulation is very rare. Whether the nuclear miRNAs interact with lncRNAs to involve in transcriptional regulation is still completely unknown. This project intends to use vascular smooth muscle cell (VSMC) as a model. Firstly, analyze lncRNA expression profiling in different phenotype VSMC, identify several nuclear lncRNAs which play important regulatory roles in VSMC phenotype transformation, and clarify the molecular mechanisms of transcriptional regulation; and then, explore the interaction between lncRNAs and nuclear miRNAs, and identify the impact of this interaction on the other interaction between lncRNAs and transcription factors, and clarify its molecular effect in the transcriptional regulation of the VSMC phenotype transformation. It is great significant to reveal the effect of non-coding RNAs interaction in the transcriptional regulation and the function in the VSMC phenotype transformation.

在人类和哺乳动物细胞中，长链非编码RNA (lncRNA)在基因转录调控中发挥着非常重要的作用，但迄今为止，与心血管相关lncRNA的研究还刚刚起步。关于microRNA (miRNA)调控机制的研究目前主要集中在胞质中miRNA对mRNA的转录后调控，而有关核内miRNA参与的转录调控研究还非常少见。对于核内miRNA能否与lncRNA产生互作及其在转录调控中的分子效应还完全未知。本项目拟以血管平滑肌细胞（VSMC）作为模型，首先，分析不同表型VSMC中的lncRNA表达谱，鉴定与VSMC表型密切相关的核内lncRNA，揭示其参与转录调控的分子机制；然后，重点探讨核内miRNA与lncRNA相互作用，阐明这种互作对lncRNA与其他转录因子互作的影响，以及在VSMC表型相关的转录调控中的分子效应。这对于深入研究非编码RNA互作在转录调控中的效应及其在VSMC表型转化的功能具有重大意义。

血管平滑肌细胞表型转化是血管重塑性疾病的共同病理特征。长链非编码RNA (lncRNA)在基因转录调控中发挥着非常重要的作用，但目前lncRNA与miRNA互作调控血管平滑肌细胞表型转化的机制知之甚少。本项目,首先通过RNA-Seq鉴定出大鼠内膜增生颈动脉与正常颈动脉中差异表达的lncRNA和mRNA，发现转录因子Hand2 (heart and neural crest derivatives expressed 2)及期邻近lncRNA Hand2-AS1呈现共表达特点，在内膜增生颈动脉表达水平显著降低。通过敲降和过表达证明，Hand2通过调控表型标志基因SM22a的表达促进血管平滑肌细胞分化，同样lncRNA Hand2-AS1也能够促进血管平滑肌细胞分化。进一步研究发现，lncRNA Hand2-AS1通过竞争性结合miR-138-5p，解除miR-138-5p对Hand2翻译抑制效应，从转录后水平上调Hand2的表达。本研究最终阐明lncRNA Hand2-AS1、miR-138-5p和hand2三者交互作用参与血管平滑肌细胞表型转化调控。