miR-322/503在缺血性心脏损伤中的修复作用与机制

Because human hearts lack regenerative capacity, cardiomyocyte loss due to a variety of reasons eventually results in loss of pump function and heart failure. This situation calls for approaches to help cardiomyocyte regeneration after injury. Effective and safe delivering ES, however, may be very challenging down the route to clinical use. Micro RNAs are powerful regulators of gene expression and biological processes. They can be synthesized, delivered locally and systemically thus hold great pharmaceutical value. miR-322/503 are reported to play important roles in differentiation processes and in regulating development of the cardiovascular system. CELF1 proteins have been shown to play roles in early embryonic development, heart function and gametogenesis. Our preliminary results show that miR-322/503 can inhibit the expression of protein levels CELF1 and then promote the differentiation of ES cells into cardiomyocytes. In this study, we will use genetic engineering techniques to filter out the target gene, explore miR-322/503 intervention directed differentiation of cardiac stem cell function and process by celf1 path with the cultivation and differentiation of ES cells, and then construct the corresponding gene knock-in and knock-out animal models with transgenic technology, using nanotechnology import the corresponding miRNA, then use an animal model of myocardial infarction to explore the role and mechanism of miR-322/503 repair of ischemic myocardial injury. It can provide more theoretical basis to applicate miR-322/503 in cardiovascular disease and provide new ideas, new targets and new directions for the prevention and treatment of myocardial injury.

因人的心脏缺乏再生能力，故因心肌梗死等各种原因均可引起心肌细胞丢失，最终导致心脏功能衰竭。在临床上，运用心肌干细胞治疗心肌损伤是一个有应用前景的崭新治疗方法，但其理论和技术都需要进一步阐述与完善。miRNA易于合成和递送使其具有重要的药物开发价值。我们的初步结果显示miRNA基因miR-322/503可以抑制CEF1的表达，促进ES细胞向心肌细胞的分化。本研究拟筛选出目标基因，通过ES细胞的培养与分化探讨miR-322/503通过CEF1干预ES向心肌细胞定向分化功能和过程。再通过转基因动物模型和相应的心肌梗死动物模型，利用纳米技术导入相应的miRNA，探讨miR-322/503对缺血性心肌损伤的修复作用，为miR-322/503在心血管疾病中的应用提供更多的理论依据，为心肌损伤临床防治提供新思想、新靶点和新方向。

在临床上，运用心肌干细胞治疗心肌损伤是一个有应用前景的崭新治疗方法，但其理论和技术都需要进一步阐述与完善。miRNA易于合成和递送使其具有重要的药物开发价值。我们发现miR-322/503在心肌及骨骼肌中作用尤为显著，初步研究结果显示miRNA基因miR-322/503可以抑制CELF1的表达，促进ES细胞向心肌细胞的分化，但研究过程中我们发现该修复作用仅局限于心肌祖细胞，随着细胞发育该修复作用减弱甚至消失，且心梗动物模型存活率低。故调整研究计划，着重研究miR-322/503在心肌缺血再灌注损伤中的作用与机制，于此同时课题组通过多系统研究发现miRNA在强直性肌营养不良1型（DM1）中也发挥重要作用。研究过程中我们发现：（1）miR-322/503通过Celf1调节心脏祖细胞发育，促进心肌分化，决定心肌细胞分化与凋亡；（2）miR-322/503通过抑制Smurf2蛋白翻译调节EZH2 /Akt/GSK3β信号途径减轻心肌再灌注损伤；（3）miR-322/503在促进骨骼肌细胞发育过程中也发挥重要作用，Celf1通过调节细胞周期撤退影响RNA毒性所致DM1成肌细胞损伤；（4）miR-206可部分逆转CUG异常扩增及Celf1过表达所致强直性肌营养不良肌肉损伤。本研究双管齐下，通过细胞及动物实验，深入探讨miRNA在心肌及骨骼肌分子机制中发挥作用与机制，为心肌缺血再灌注损伤及DM1临床防治中供新的靶点和线索。