核纤层蛋白LaminA/C突变介导的Rb/E2F1信号通路异常引起家族性房室传导阻滞的分子机制研究

核纤层蛋白LaminA/C由LMNA基因编码，参与组成核膜的核纤层结构，可介导胞内信号转导，突变后会引起家族性房室传导阻滞等心脏病，但致病机制不清。课题组前期在房室传导阻滞家系中鉴定了LMNA基因新突变p.W520R，预实验提示该突变蛋白可能通过干扰Lamin A/C介导的Rb/E2F1信号通路，引起下游KCNK1等一群离子通道基因表达下调，进而导致心肌细胞电活动异常，引发房室传导阻滞疾病发生。本项目拟针对该信号通路，基于病人自身来源诱导性多能干细胞（iPSC），诱导分化获取心肌细胞，并结合心肌细胞株AC16及HCM，运用分子生物学及干细胞技术，着重阐明p.W520R突变通过LaminA/C介导的Rb/E2F1信号通路下调KCNK1离子通道基因的详细分子机制，并结合膜片钳分析突变蛋白对心肌细胞电活动的影响效应,探讨LMNA基因突变引起家族性房室传导阻滞的新机制，探索干预疾病的可能分子靶点。

Nuclear lamina protein LaminA/C encoded by LMNA gene, and participated in forming nuclear membrane and its signaling transmission. Mutations LMNA gene caused severe cardiac diseases such as severe atrioventricular block, but its mechanisms were unclear. In previous study, we reported a family with atrioventricular block and identified a novel pathogenic mutation LMNA p.W520R. Our preliminary experiments suggested that this mutation may lead to the dysfunction of nuclear lamina Rb/E2F1 signaling pathway mediated by LaminA/C, which resulted in abnormal expression for multiple ion channel genes such as KCNK1 and the electrical activity changing of cardiomyocyte, thus causing atrioventricular block. Therefore, this project based on the Rb/E2F1 signaling pathway and used induced pluripotent stem cells (iPSC) of patients, human myocardial cell model AC16 and HCM, using stem cell and molecular biology techniques to elucidate the p.W520R mutation effects for the regulation mechanism between Rb/E2F1 and KCNK1 gene. Moreover, we would use patch clamp technique to further investigate disease effects of p.W520R mutation, in order to clarify the molecular mechanism between LMNA gene mutation and atrioventricular block, and to explore the possible molecular targets intervention for atrioventricular block.