突触结合蛋白7在心脏自主神经活动及房颤发生中的作用  

Role of synaptotagmin 7 in cardiac autonomic nerve activity and the pathogenesis of atrial fibrillation

作　　者：杨璐梓 申晶 闫敏 李佳蕾 周岚 曹济民 YANG Luzi;SHEN Jing;YAN Min;LI Jialei;ZHOU Lan;CAO Jimin(Key Laboratory of Cellular Physiology,Ministry of Education,Department of Physiology,Shanxi Medical University,Taiyuan 030001,China)

机构地区：[1]山西医科大学生理学系,细胞生理学教育部重点实验室,太原030001

出　　处：《生命的化学》2021年第9期2001-2011,共11页Chemistry of Life

基　　金：国家自然科学基金面上项目(8167021355);山西省“1331工程”重点学科建设计划(1331KSC)。

摘　　要：突触结合蛋白7(synaptotagmin 7, SYT7)是一种钙离子感受器,介导囊泡分泌过程的延迟性非同步释放过程。但SYT7在调控自主神经活动及房颤(atrial fibrillation, AF)发生中的作用尚不清楚。本研究利用CRISPR/Cas9技术构建SYT7基因全身敲除(SYT7 KO)小鼠模型;用尾静脉注射乙酰胆碱(acetylcholine,Ach)(66μg/mL)+Ca Cl2(10 mg/mL)(注射剂量0.01 mL/10 g)诱发小鼠AF;用心电图、小动物心脏超声、免疫组织化学染色、高效液相色谱-电化学检测(HPLC-ED)、RT-q PCR及Western blot等技术检测AF、心功能、心房神经支配、去甲肾上腺素(norepinephrine, NE)释放、心房自主神经及AF相关蛋白的表达水平。结果显示,与野生型对照小鼠相比,SYT7 KO小鼠诱导性AF发生率增高(P<0.01)、左心房内径扩大、心房收缩功能下降;心房迷走神经密度增高、交感神经密度降低、交感神经递质释放减少;心房肌中胆碱乙酰转移酶(choline acetyltransferase, ChAT)、乙酰胆碱敏感的内向整流钾通道Kir3.1和心房钠尿肽前体(pro-ANP, NPPA)表达增高。本研究结果提示,SYT7有抑制胆碱性AF的作用,其机制与SYT7调节交感/迷走神经活动平衡及Kir3.1通道表达有关。SYT7有可能成为胆碱性AF的一个治疗靶点。Synaptotagmin 7(SYT7) is a Ca2+ sensor which mediates the delayed non-synchronous release of vesicle secretion. However, the role of SYT7 in the regulation of atrial autonomic nerve activity and the pathogenesis of atrial fibrillation(AF) is unclear. In this study, SYT7 gene global knockout(SYT7 KO) mice were created using the CRISPR/Cas9 technique. AF was induced by intravenous injection of acetylcholine(Ach)(66 μg/mL)+CaCl2(10 mg/mL)(0.01 mL/10 g). AF was monitored by electrocardiogram(ECG).Echocardiography, immunohistochemistry, high-performance liquid chromatography-electrochemical detection(HPLC-ED), RT-qPCR, and Western blot were used to evaluate cardiac performance, atrial innervation, sympathetic neurotransmitter norepinephrine(NE) level, and atrial expressions of autonomic nerve-and AF-related proteins. Results showed that, compared with the wild type(WT) mice, SYT7 KO mice showed increased Ach-induced AF(P<0.01), enlarged left atrial diameter, atrial systolic dysfunction, and conduction abnormality;SYT7 KO mice also showed increased vagal innervation but decreased sympathetic innervation, and reduced NE level, while exhibited increased expressions of choline acetyltransferase(ChAT),Ach-sensitive K+ channel(IK,Ach)(Kir3.1), and atrial natriuretic peptide precursor(pro-ANP, NPPA), in the atria. This study suggests that SYT7 can suppress cholinergic AF by regulating atrial sympathetic/vagal nerve balance and the expression of IK,Ach channels in the atria. SYT7 may potentially be a therapeutic target for cholinergic AF.

关 键 词：突触结合蛋白7 自主神经 房颤 乙酰胆碱敏感的内向整流钾通道 

分 类 号：R541.75[医药卫生—心血管疾病]