miR-23a调控TRPM1介导的钙信号通路在老年性房颤中的分子机制

我们近来的研究对心房衰老和房颤行表达谱测序，发现与二者均相关的miR-23a和受其调控下游TRPM1基因。预实验在HEK293细胞转染TRPM1，可记录到TRPM1介导的阳离子电流，伴有胞内Ca2+浓度显著增加。经AngII培养的老年鼠成纤维细胞，磷酸化ERK1/2的蛋白明显增加。因此提出假说，miR-23a通过调控下游TRPM1基因，导致细胞钙内流和ERK1/2磷酸化增加，诱导心房成纤维细胞增殖分化，从而参与老年性房颤的发生。本课题拟：1）在细胞模型检测TRPM1介导的离子流、钙内流和TRPM1蛋白，评价干预miR-23a的效应。2）建立TRPM1基因过表达小鼠模型，监测自发房颤、AngII诱导房颤和电生理诱导房颤。3）在转基因动物模型和老年房颤患者成纤维细胞，论述“miR23a-TRPM1-钙信号通路-老年性房颤”的分子机制。本研究旨在阐明老年性房颤新的分子机制，为其干预提供新的思路。

Our recent study performed miRNA-sequencing and mRNA-sequencing on atrial aging and atrial fibrillation (AF), identifying miR-23a which was related with both atrial aging and AF and its downstream target TRPM1 gene. Preliminary experiments on HEK 293 cells transfected with TRPM1, showed the TRPM1-mediated cation current, and the concentration of intracellular Ca2+ was significantly increased. In the fibroblasts incubated with AngII from aged rat, it showed the increased expression of phosphorylated ERK1/2 protein. Herein, the hypothesis is raised that TRPM1 channel regulated by miR-23a might result in calcium influx and ERK1/2 phosphorylation, then induce the differentiation and proliferation of fibroblasts contributing to the development of aged AF. The present study is aimed to: 1) examine the cation current mediated by TRPM1, intracellular calcium influx and the protein expression of TRPM1 in two kinds of fibroblast models, and assess the effects of the interventions on miR-23a. 2) create transgenic mice model by overexpressing TRPM1, and moniter the phenotype of spontaneous AF, AngII induced AF and electrophysiological stimulation induced AF. 3) clarify the molecular mechanisms of “miR-23a-TRPM1-calcium signaling-aged AF” in transgenic mice model and fibroblasts from aged AF patients. The study is designed to investigate novel molecular mechanisms of aged AF and to provide some new theoretical basis for its management.