miR-21调控Nox4/ROS在心力衰竭心肌纤维化中的作用和机制研究

The role of myocardial fibrosis in chronic heart failure（CHF） is gaining increasing attention. Inhibition of myocardial fibrosis has been proved to be a new target of prophylaxis and treatment of CHF. MicroRNA-21（miR-21) and reactive oxygenic species (ROS) are both involved in the pathogenesis of myocardial fibrosis. Activation of NADPH oxidases 4 (Nox4) is the core steps in producing ROS during myocardial fibrosis. In former studies, we found that miR-21 promote myocardial fibrosis ,regulate NOX4 and ROS, but the mechanism study has not been reported. We then speculate that the promoter action in fibrosis of miR-21 maybe root in its regulation action in Nox4/ROS. We also hypothesize that miR-21 regulate Nox4 and increased the production of ROS, promote myocardial fibrosis. Accordingly, the present project is proposed to is study in vivo and in vitro to investigate: 1. The role of miR-21 played in the mechanism of myocardial fibrosis. 2. The regulatory mechanism of ROS production by miR-21. 3. Investigate the mechanism of miR-21 in regulation of NOX4 and the producing of ROS in the development of myocardial fibrosis.Thus we make our effort to provide a new insight in prevention of myocardial fibrosis and treatment of CHF.

心肌纤维化在慢性心力衰竭中的作用受到重视，干预心肌纤维化已成为心力衰竭防治的新靶标。microRNA-21（miR-21）和活性氧物质(ROS)参与心肌纤维化发生发展，NADPH氧化酶4（Nox4）的激活是心肌纤维化过程中ROS产生的核心环节，前期研究发现miR-21促进心肌纤维化，并与NOX4和ROS的生成密切相关，而机制研究未见报道，我们推测miR-21促纤维化的作用与调控Nox4/ROS有关，故提出科学假说：miR-21调节Nox4，促进ROS的生成，介导心力衰竭心肌纤维化。本项目拟从离体和在体多水平开展研究，解决下列关键问题: 1. 明确miR-21参与心力衰竭心肌心肌纤维化过程的方式; 2. 研究miR-21调控ROS 生成的机理; 3. 探索miR-21调控NOX4，介导ROS生成在参与心肌纤维化中的可能机制，为干预心肌纤维化，防治心衰提供新的路径。

心肌纤维化与心力衰竭的进展和预后有密切关联，是引起心室重塑的关键因素，阻止和逆转心肌纤维化是心力衰竭防治的重要靶点。 miR-21参与多种心血管系统的生理及病理过程，在心脏表达丰富，在心血管疾病中发挥广泛而重要的作用，调节NOX4/ROS可能是miR-21参与心肌纤维化过程的重要机制。本研究内容包括：建立心力衰竭心肌纤维化实验动物模型和体外培养心肌成纤维细胞模型，检测miR-21和NOX4的表达、心功能相关指标、心肌纤维化相关标志物的表达、ROS生成和变化。在动物模型和体外培养心肌成纤维细胞模型特异性抑制和过表达miR-21，研究miR-21对心力衰竭心肌纤维化，NOX4，ROS的影响。体外培养心肌成纤维细胞模型，检测并分析心肌纤维化过程中miR-21是否调控NOX4，促进ROS生成及参与心力衰竭心肌纤维化的过程。结果显示：（1）miR-21参与调控心肌纤维化。（2）抑制miR-21能够下调NOX4、减少ROS的生成。 （3）抑制miR-21通过调控NOX4/ROS信号通路改善了心肌纤维化。科学意义：慢性心力衰竭发病机制不明，死亡率高，心肌纤维化是引起心室重塑的关键因素，与心力衰竭的进展和预后有密切关系。本项目探索miR-21调控NOX4/ROS的内在作用机制，深化对miR-21对心肌纤维化的调控机制的理解，探求心力衰竭心肌纤维化的新治疗策略。