microRNA-17/145协同调控线粒体融合蛋白和Ca2+信号交互网络引发心肌肥厚的新机制

This application is based on the prevention and treatment of major medical problems of myocardial hypertrophy and heart failure. It's the first time to introduce microRNA into heart mitochondrial fusion. Mfn2, as an important node protein, links microRNA and Ca2+ signal interactive network and hypertrophic key proteins. To test the hypothesis we propose several experiments including molecular biology, morphological and functional testing, gene chip, luciferase reporter assay and chromatin immunoprecipitation assay using animal model, lentivirus carrier system, transgenic animal and cell culture. This application will be elucidated: changes of miR-17 and miR-145 expression trigger abnormal morphology and the function of the heart and mitochondria; miR-17 and miR-145 coordinatly regulate the disorder of hypertrophy-related target proteins (Mfn2 and CaN CaMKII); transcription factor Sp1 and CREB regulate the expression of miR-17 and miR-145. It's the first time to report coordinate regulating mechanism of Sp1, miR-17, Mfn2 signaling pathways and CREB, miR-145, CaN, CaMKII signaling pathways in the process of hypertrophy, with the purpose of providing theoretical basis and therapeutic targets for new drug research and development.

本申请立足于重大医学难题心肌肥厚和心力衰竭的防治。首次将microRNA引入心脏线粒体融合，将Mfn2作为重要的节点蛋白，将microRNA与Ca2+信号交互网络和肥厚关键蛋白联系起来，拟通过动物模型、慢病毒载体系统、转基因动物和细胞培养，应用分子生物学、形态学和功能学检测、基因芯片、Luciferase荧光素酶报告基因、染色质免疫共沉淀等技术研究microRNA协同调控线粒体肥厚通路。本申请将阐明：miR-17和miR-145表达改变引发心脏及线粒体形态和功能的异常；miR-17和miR-145协同调节肥厚相关靶蛋白（Mfn2和CaN、CaMKII）的失调；转录因子Sp1及CREB对miR-17和miR-145表达的调控。首次报告出Sp1、miR-17、Mfn2信号通路以及CREB、miR-145、CaN、CaMKII信号通路协同调节肥厚过程的新机制，为新药研发提供理论依据和治疗靶点。

本申请立足于重大医学难题心肌肥厚和心力衰竭的防治。采用心肌肥厚模型从离体细胞水平和在体动物水平，系统研究了miR-20b通过靶向调控Mfn2及其介导的钙交互参与心肌肥厚的确切分子机制。结果表明心肌肥厚损伤诱导miR-20b、miR-15a等表达上调，最终选择上调显著并在心脏疾病研究较少的miR-20b进行后续研究。miR-20b通过抑制Mfn2表达和功能，干扰线粒体融合，并干扰内质网和线粒体的互作，减少钙离子从内质网转运到线粒体，促使胞浆中钙离子浓度升高，从而结合CaM，激活CaMKIIδ和CaN，启动肥大机制，诱发心肌肥厚的发生。本项目将miRNA引入心脏线粒体融合，把Mfn2作为重要的节点蛋白，将miRNA与Ca2+信号交互网络和肥厚关键蛋白联系起来，补充过去仅仅是从miRNA调控肥厚基因表达的角度研究其发病机制，进一步从线粒体融合方面证实miRNA在心肌肥厚中的作用，探讨线粒体融合蛋白Mfn2与Ca2+信号的交互关系和由此引发心肌肥厚功能状态的改变，为心肌肥厚的防治提供新的理论依据和干预靶点。同时还进行了一些其他关于心肌肥厚和心衰的科学研究。神经肽Y可诱导大鼠心脏功能障碍和心肌肥厚；miR-143在缺血缺氧诱导的心肌凋亡中的作用以及通过线粒体途径调控的新机制；枸杞多糖改善由miR-1过表达造成的心脏不利性结构重塑和功能紊乱，有潜力开发成为防治心力衰竭的新候选药物。本项目已培养博士生2名、硕士生5名，已发表SCI索引论文5篇、中文核心期刊论文2篇，获得科研奖励2项。