RNA结合蛋白QKI调控血管平滑肌细胞心肌素Myocardin对动脉粥样硬化的作用研究

The proliferation and migration of vascular smooth muscle cells (VSMCs) play a key role in the occurrence and development of atherosclerosis(As). It was reported that RNA-binding protein QKI is closely related to the proliferation and differentiation of tumor cells and can influence the proliferation and differentiation of VSMCs by acting on Myocardin, the specific transcription factor of VSMCs. Our previous studies showed that GSK-3β could regulate the proliferation and differentiation of VSMCs through the phosphorylation of Myocardin. Besides, QKI and Myocardin -v1 was increased when the proliferation activity of VSMCs was enhanced, while Myocardin-v3, which maintained the contractile state of VSMCs,was decreased. So we hypothesized that: QKI can regulate the phenotypic transformation of VSMCs through selective splicing of Myocardin pre-mRNA, and can influence the pathological changes of As. We intend to use previously constructed VSMCs that can stably expresse Myocardin to study whether QKI can regulate VSMCs phenotypic transformation by regulating Myocardin and how it works. Meanwhile, a new type of As model of hamster is applied to explore whether QKI can regulate the phenotypic transformation of VSMCs and can influence the pathological changes of As. In short, our goal is to make sure whethe and how QKI can regulate Myocardin and affect on AS. It will be systematically explored from three aspects of molecule-cell-animal in order to provide a new idea and therapeutic target for the prevention and treatment of As.

血管平滑肌细胞（VSMCs）的增殖与迁移在动脉粥样硬化（As）的发生发展中起关键作用。RNA结合蛋白QKI与肿瘤细胞的增殖分化密切相关，并可作用于VSMCs特异性转录因子心肌素（Myocardin），影响VSMCs的增殖分化。我们前期研究发现，GSK-3β能通过对心肌素的磷酸化调控VSMCs的增殖分化，当VSMCs增殖时，QKI和心肌素-v1增多，而维持VMSCs呈收缩态的心肌素-v3减少。因此提出假设：QKI可通过选择性剪接心肌素pre-mRNA调节VSMCs表型转化，影响As进程。本项目拟使用前期构建的稳定表达心肌素的VSMCs深入研究QKI对心肌素及VSMCs表型转化的作用机制；并构建高度拟人化的新型As仓鼠模型，研究QKI在体内能否调节VSMCs表型转化来影响As进程；从分子-细胞-动物多层面研究QKI调控心肌素对As发生发展的作用机制，以期为As的防治提供新的治疗靶点及理论依据。

动脉粥样硬化(As)是导致心血管疾病的主要病理基础，其病因复杂，除内皮损伤外，脂质代谢紊乱、血管平滑肌细胞(VSMCs)的异常增殖与迁移在As疾病进程中亦起到非常重要的作用。本课题组在血管平滑肌细胞层面进行分子通路及相关基因的微观研究的同时，建立了新型代谢性As仓鼠模型，发挥其高度拟人化物种优势，开展As疾病动物体内研究。研究发现：体外细胞实验中QKI通过调节VSMCs中Myocardin-v3和Myocardin-v1 mRNA之间的平衡调控VSMCs表型转换；动物体内实验中，颈总动脉中QKI的减少可以逆转血管平滑肌细胞的合成表型，减轻仓鼠模型的As病变，改善颈总动脉管腔狭窄程度；肝脏和脂肪中的QKI表达减少可以下调相关基因表达来降低血脂水平和炎症反应，减缓As的进程。除此之外，我们还发现，橙皮素干预的QKI下调可通过Nrf2／HO-1信号通路对非酒精性脂肪肝体外模型氧化应激发挥保护作用；此外，其在动物体内还能通过Nrf2／keap-1信号通路增加肝脏抗氧化应激的能力，缓解非酒精性脂肪肝。本课题研究结果丰富了人们对QKI调控VSMCs的增殖、迁移和脂代谢在As进程中的作用机制的认识，可为防治As相关疾病提供新的思路。.目前，本项目基金资助的论文已在国内外学术期刊上共发表11篇，其中在SCI收录期刊上发表论文2篇、在北大核心期刊上发表论文3篇、在科技核心期刊上发表论文5篇、在普通期刊上发表论文1篇。培养硕士研究生4名，在本地区相关研究领域构建了一个稳定的、多学科交叉的、以青年为主的由高级-中级-初级-研究生组成的科研人员梯队。