microRNA-423调控CKIs影响扩张型心肌病病生及转归的机制探讨

Dilated cardiomyopathy is the dominant etiological factor of chronic heart failure. Induction of cardiomyocyte regeneration and reentering the cell cycle is a promising treatment in cardiac repair and prevent from the progression of heart failure. CKIs (Cdk inhibitors) regulate cell cycle progression in a negative matter and can be repressed post-transcriptionally by miRNA. However, the precise mechanisms underlying the role of miRNA through the CKIs-dependent way in myocardium renewal are poorly understood. Our previous study demonstrated that the levels of CKIs proteins increased in the dilated cardiomyopathy mice and were down-regulated by miR-423. Otherwise, overexpression of miR-423 enhanced cardiomyocyte proliferation. In light of this finding and to further gauge the role of the miRNA in myocardium regeneration through CKIs pathway, we will use bioinformatics to find the putative target of miR-423 and determine it by the dual luciferase reporter assay system. Then the lentivirus productions of target sequences will be transfected into the cardiomyocyte to up/down-regulate the target gene. By altering the level of miR-423, we will examine the cardiomyocyte proliferation, the transition of cell cycle in vitro and assess the cardiac performance in vivo. We will perform the experiments in an integrated way and the scientific quest for the basic mechanisms that miRNA are responsible for the development and progression of heart failure will be elucidated.

扩张型心肌病是慢性心力衰竭的主要原因。促进心肌再生可改善扩张型心肌病的病理生理从而延缓心衰进展。CKIs是细胞周期负向调控因子，miRNA参与其转录后调节机制。miRNA能否抑制CKIs促进心肌细胞增殖，改善心功能目前尚不清楚。我们前期研究中发现BALB/C扩张型心肌病模型小鼠CKIs表达增加，过表达miR-423能下调CKIs，促进心肌细胞增殖。本项目拟进一步探讨miRNA通过CKIs调控心肌再生的机制，采用生物信息学及双荧光素酶实验预测并鉴定miR-423 的靶基因，构建靶基因过表达/敲除载体转染心肌细胞，通过上调/下调miR-423，观察心肌细胞增殖，细胞周期变化及CKIs表达，并观察扩张型心肌病小鼠的病生及疾病转归。本课题拟从分子、细胞和动物水平上开展整合性研究，相关结果将有助于揭示miRNA调控心肌细胞增殖再生的机制，为逆转扩张型心肌病的进程提供有意义的治疗靶点。

心肌细胞的增殖和再生能够改善许多心血管疾病的预后，延缓疾病进程。心肌细胞的增殖涉及CDK和CKIs的调控，后者是细胞周期负向调控因子，miRNA参与其转录后调节。。本项目从分子、细胞水平开展了整合性研究，揭示了miR-423-5p通过调控CKIs相关因子影响心肌细胞增殖再生，为逆转扩张性心肌病的进程提供了潜在的治疗靶点。