MicroRNA调控TLR4信号通路在早期缩窄性心包炎致心肌纤维化中的作用

Chronic constrictive pericarditis (CP) can lead to myocardial fibrosis, but recently, some research suggested that the early constrictive pericarditis could cause left ventricular systolic function decreases. The molecular mechanism of induction and the association with the launch of myocardial fibrosis have not been reported to this day. Our research team has found early CP can reduced left ventricular systolic function and cardiomyopathy using two-dimensional speckle tracking echocardiography using Wistar rats CP animal models. On the base of early work, we plan to study further the key point of TLR4 signal pathway (MAPK/ERK1/2, Jak/STAT and NF-κB) and the variation of various molecular using CP model of rats and in vitro rat myocardial cells. To study related miR-29 and miR-223 in response to different inflammatory stimulation (IL-6, INF-γ and LPS) and the regulation of downstream effect genes (NGF, TGF-1β and MMPs/TIMPs). Study of these problems will help us understand the relationships of miRNA upstream control genes and downstream target genes with the important inflammation coupling signal path in the process of early CP induced myocardial fibrosis. In addition, studies of the molecular mechanism thoroughly would provide more theory base and thinking including prevention, diagnosis and treatment of myocardial fibrosis.

慢性缩窄性心包炎（CP）可以导致心肌纤维化，但最新研究表明早期缩窄性心包炎即能够引发左室收缩功能减低。其诱导心肌病变的分子机制，以及是否启动了心肌纤维化，迄今国内外尚不清楚。本课题组首次运用Wistar大鼠CP动物模型，利用二维斑点追踪显像技术证实了早期CP可引发左室收缩功能减低。本项目拟在前期工作的基础上，研究早期CP致心肌纤维化TLR4信号通路（MAPK/ERK1/2，Jak/STAT及NF-κB）的关键调控节点和各种调控分子的变化规律；鉴定相关miR-29及miR-223在应对不同炎症刺激（IL-6、INF-γ、LPS等）条件下调控下游效应基因（NGF、TGF-1β、MMPs/TIMPs），从而揭示大鼠早期CP致心肌纤维化过程中这些miRNA的上游调控基因和下游效应基因与炎症偶联信号通路之间的相互联系，为早期CP致心肌纤维化的预防、诊断、治疗提供更多的依据与思路。

缩窄性心包炎（Constrictive Pericarditis，CP）是由于纤维化、钙化和粘连的心包弹性丧失所导致的心室舒张期充盈异常，同时也伴随着收缩功能的异常，其病理基础是心肌的纤维化，CP早期心肌组织纤维化的机制是其治疗和预后研究的基础和关键。本研究以小型动物大鼠为模型制备对象，探索不开胸心包腔注射致炎剂制备CP模型的方法，从心包弹性丧失和心室舒张异常两方面对模型进行验证。在成功制备的大鼠CP模型的基础上，应用二维斑点追踪成像技术系统性评价CP致大鼠心肌损伤的特点和程度，从超声和病理两方面表明CP所致心肌纤维化有从心外膜下心肌向心内膜下心肌演进的趋势。利用高通量测序检测大鼠心肌组织，发现模型组miR 146a异常高表达，在之后的Realtime PCR验证中，发现miR 146a在CP发展过程中的表达为先增高后降低的动态变化；在大鼠心肌组织中发现并在原代培养的新生大鼠心肌成纤维细胞中验证了miR 146a靶向TRAF6、IRAK1负向调控心肌纤维化的机制；此外，同样在心肌组织和细胞水平发现并验证了LPS/TLR4上调TGFβ1/Smads在CP致心肌纤维化机制；上述基础研究为缩窄性心包炎早期诊断和治疗提供了新的靶点和思路。