神经上皮转化因子Net-1介导心肌纤维化的分子调控机制

Various cardiovascular disease almost have different degree of myocardial fibrosis, and it is also one of the important risk factors of cardiac deaths. So far there is no any reported about the effect of neuroepithelial conversion factor-Net-1 in myocardial fibrosis. Preliminary results of this research was first discovered Net-1 is significantly increased in the mice of myocardial fibrosis. It hint that Net - 1 participated in the pathological process of myocardial fibrosis. In this regard, the mechanism of Net-1 in regulation of myocardial fibrosis will be explored by using techniques such as animal model, cellular experiment and molecular biology and so on. This project tries to clarify: (1) Net - 1 form a complex by combining with GSK - 3βto adjust the activation of Wnt/β- catenin signaling pathway, promoting the synthesis of fibroblasts collagen, and it involved in the role of myocardial fibrosis; (2) To demonstrate that knock-down of Net-1 could relieve myocardial fibrosis with deactivating the Wnt/β- catenin signaling pathway. Net-1 may be is an important player in the process of myocardial fibrosis and the potential drug target of myocardial fibrosis. This project will provide a new theoretical basis for the prevention and treatment of myocardial fibrosis and treatment of new targets.

多种心血管疾病均伴有心肌纤维化的发生，心肌纤维化是导致心源性猝死的重要危险因素之一，目前关于神经上皮转化因子Net-1在心肌纤维化的作用尚无相关报道。本研究前期结果首次发现了心肌纤维化模型小鼠心肌组织Net-1含量显著增高，提示Net-1参与了心肌纤维化的病理过程。本研究通过建立纤维化模型、细胞实验和分子生物学等技术，探讨Net-1调控心肌纤维化的机制。本项目试阐明：⑴Net-1可能通过作用于GSK-3β调节了Wnt/β-catenin信号通路的激活，促进成纤维细胞胶原合成，参与心肌纤维化的作用；⑵敲减Net-1可以促进Wnt/β-catenin信号通路的失活，缓解心肌纤维化的进展，Net-1可能是心肌纤维化潜在治疗靶点。本项目将为心肌纤维化基础研究与临床防治提供重要的理论依据。

心脏纤维化是导致心源性猝死的重要危险因素之一，神经上皮转化因子1（Net-1）属于Rho鸟嘌呤核苷酸交换因子家族中的一员，该家族蛋白具有激活和调节Rho家族成员的功能。本项目通过构建在体TAC/离体TGF-β1诱导的心脏纤维化模型，确定了Net-1在心脏纤维化时的表达变化。发现心脏纤维化发生时Net-1表达水平增加；敲减Net-1能够减轻TGF-β1诱导的心肌成纤维细胞纤维性变，从细胞水平和在体转基因小鼠，阐明特异性敲减Net-1对心脏纤维化的抑制作用。而过表达Net-1诱导成纤维细胞纤维性变，促进心脏纤维化。本项目揭示了Net-1调控心脏纤维化的机制，阐明了Net-1通过β-catenin信号通路参与心脏纤维化的调节作用及其分子机制。Net-1能够促进GSK3β磷酸化水平，使其失活，进而促进β-catenin入核并激活心脏纤维化相关蛋白的表达。敲减GSK3β能够减轻TGF-β1诱导的心脏成纤维细胞向肌成纤维细胞的转变；过表达Net-1同时敲减GSK3β能够抑制由Net-1诱导的心脏成纤维细胞向肌成纤维细胞的转变。本项目阐明了Net-1可能通过与GSK3β结合，促进GSK3β的磷酸化，从而增强β-catenin的入核，从而促进心脏纤维化的分子机制。主要结论及科学意义：本项目揭示了Net-1在心脏中发挥重要的作用，Net-1通过调节GSK3β/β-catenin通路参与调控心脏纤维化，本项目探索靶向敲减Net-1的抗心脏纤维化作用，为临床心脏纤维化的治疗及药物研发提供新思路和新靶点。