Rho/Rock信号通路对压应力诱导心房缝隙连接和离子通道重构的调控作用研究

Atrial fibrillation is common and refractory, which significantly increase mortality by causing heart failure and stroke. Atrial gap junction and ion channel remodeling under changes of atrial mechanical circumstances are closely related to the occurrence and maintenance of atrial fibrillation. However, the underling mechanism has not been clearly elucidated. Compressive stress is a major form of mechanical stress in atrium. We have previously observed the changes of mRNA and protein expression of connexin and ion channels of neonatal rat atrial myocytes under compressive force in vitro. Besides, Rho/ROCK pathway had been shown to be a mechanosensor and plays a significant role in force transmission. This study is aimed to develop in vitro and in vivo methods to apply compressive force on cardiac myocytes, observe the Rho/ROCK kinase activity of atrial myocytes during pressure overload, find optimal ways to suppress Rho/ROCK pathway and explore its regulatory effect on atrial gap junction and ion channel remodeling. This study is critical for elucidating the mechano-electric feedback mechanism of AF and bound to provide a molecular biological evidence and theoretical basis for improving the upstream regulation and treatment effect of atrial fibrillation.

心房颤动常见而顽固，引发心衰、卒中等并发症使其死亡率显著高于非房颤人群。心房在异常力学环境下发生的缝隙连接和离子通道重构是房颤发生和持续的重要基础，但应力超负荷导致心房肌细胞缝隙连接和离子通道重构的信号转导通路及其调控机制远未阐明。压应力是心房重要应力构成，本团队前期研究显示压应力可导致心房肌细胞缝隙连接和离子通道蛋白表达改变。此外，Rho/ROCK信号通路在生物体内具有明显的机械敏感性，在力学信号向细胞内传递过程中扮演重要作用。本研究拟分别构建心房肌细胞体内、体外压应力超负荷模型，通过观察心房肌细胞及组织在压应力刺激下Rho/ROCK信号通路的活性变化，筛选有效干预Rho/ROCK信号通路的方法，探究其在压应力诱导心房肌缝隙连接和离子通道重构过程中的调控作用，旨在为阐明房颤力学机制，优化房颤上游干预手段，提高房颤治疗效果提供新的分子生物学证据和理论基础。

心房颤动常见而顽固，其机制未完全阐明，以心房內压力升高为特征的力学环境改变常见于易发房颤的疾病，其中压应力是心房应力的重要构成。已知由缝隙连接和离子通道蛋白表达下降为代表的心房电重构以及由成纤维细胞活化和细胞外基质沉积为代表的心房结构重构贯穿于房颤发生及维持的全过程，Rho/ROCK信号通路被证实具有机械敏感性，但其是否参与压应力介导的心房肌细胞缝隙连接和离子通道重构，以及成纤维细胞活化的过程，目前尚无研究报道。外科消融手术是最有效的房颤根治手段，但外科术式存在诸多争议。本项目分别围绕上述问题展开了离体、在体研究和临床系统评价，成功优化离体心房肌细胞压应力超负荷模型并观察到压应力刺激伴随心房肌细胞Cx43、L-Ca2+α1C表达量下降，Rho/ROCK信号通路可能参与了由压应力介导的心房钙离子通道重构，心房成纤维细胞Rho/ROCK信号通路具有机械敏感性，抑制Rho/ROCK信号通路可降低成纤维细胞活性，部分逆转由横主动脉缩窄导致的大鼠左房结构重构，Rho/ROCK信号通路可能参与了间歇性低氧下Cx43的调控过程；自主神经节丛消融仅能提高经导管消融的疗效，而对外科消融没有改善，对于非选择性的外科房颤患者，双心房消融并不优于单纯左房消融，左心房迷宫术式可能具有最佳的收益-风险比。本研究进一步丰富了当前对房颤力学机制的认识，对Rho/ROCK信号通路的研究初步揭示了它的力学敏感性，为进一步深入探究它的力学转导作用，筛选适宜的干预方式创造了条件，相关研究成果为进一步深入阐释房颤力学机制，优化房颤治疗策略奠定了理论和方法学基础。