miRNA-590-3p调控的PDGF-BB信号通路在心房重构致心房颤动中的作用研究

Atrial structural and electrical remodeling caused by Cx43 remodeling and atrial fibrosis play a part in the atrial fibrillation. Our previous research showed that the Platelet derived growth factor (PDGF) mediated the Cx43 remodeling and atrial fibrosis. MicroRNA-590-3p(miR-590-3p) is an important anti-fibrotic factor, PDGF-B as a target gene of miR-590-3p. Therefore we hypothesize that down-regulation of miR-590-3p can lead to the atrial fibrillation via Cx43 remodeling and atrial fibrosis by activating thePDGF-BB signaling pathway.There is none of the report for the related research in the literature.The miR-590-3p，PDGF-BB，Cx43，CollagenⅠwill be measured for the patients with atrial fibrillation and rapid atrial pacing canine models by RT-qPCR、Western-blot; Dual luciferase reporter gene assay kit will verify PDGF-B as a target gene of miR-590-3p; miR-590-3p overexpression or underexpression mouse models will be made by lentiviral vector transfection. This study is to lay the foundation for revealing the pathogenesis of atrial fibrillation and provide new strategies for the prevention and treatment of atrial fibrillation.

Cx43重构及心房纤维化引起的心房电重构及结构重构是房颤发生的重要机制。我们前期的研究工作发现血小板衍生生长因子（PDGF）参与Cx43重构及心房纤维化，微小RNA-590-3p(miR-590-3p)是重要的抗纤维化因子，PDGF-B是miR-590-3p的潜在靶基因。因此，假设由于不同原因下调的miR-590-3p参与了PDGF-BB信号通路的调控，导致Cx43重构及心房纤维化而致房颤，相关的研究尚未见文献报道。我们将采用RT-qPCR、Western-blot检测房颤患者、快速心房起搏房颤犬心房miR-590-3P、PDGF-BB、Cx43、I型胶原，双荧光素酶报告基因系统验证PDGF-B是miR-590-3p调控靶基因，慢病毒转染构建miR-590-3p过表达及抑制表达小鼠模型，探讨miR-590-3p调控的PDGF-BB信号通路在心房重构中的作用机制，为房颤的防治提供新的思路。

本项目首次探索了microRNA-590-3p（miR-590-3p）在房颤心房Cx43重构和心房纤维化中的作用，及其具体的机制。我们发现，房颤患者右心房miR-590-3p表达下降，PDGF-B/PDGFR-β信号通路表达上调，Cx43表达下调，心房纤维化沉积增加。我们利用左心房快速起博，构建了不同房颤时程的房颤犬模型。结果显示，随着房颤时间的延长，犬左右心耳，左右心房miR-590-3p表达逐渐下降，房颤第2周后一直维持在较低的表达水平；随着房颤时间的延长，犬左、右心耳和左、右心房PDGF-B、COL1表达和胶原容积分数逐渐增加；犬左、右心耳和左、右心房PDGFR-β蛋白表达在房颤早期无明显变化，从房颤第2周起PDGFR-β表达逐渐增加；房颤犬左、右心耳和左、右心房Cx43表达下调。上述结果进一步表明，miR-590-3p下调可能通过上调PDGF-B/PDGFR-β信号通路，参与心房Cx43重构和心房纤维化的发生。随后，我们利用miR-590-3p inhibitors分别干预人心房成纤维细胞和人心肌细胞，结果显示miR-590-3p inhibitors组心房成纤维细胞PDGF-B和COL-1表达明显上调，miR-590-3p inhibitors组人心肌细胞PDGF-B表达上调，而Cx43表达下调。我们同时利用双荧光素酶报告基因试验证实PDGF-B是miR-590-3p直接作用的靶基因。从而在体外证实，miR-590-3p通过靶向调控PDGF-B信号通路，参与房颤心房Cx43重构和心房纤维化的发生。最后，我们经尾静脉注射miR-590-3p过表达和低表达慢病毒载体，构建miR-590-3p过表达/低表达SD大鼠。其结果显示，miR-590-3p过表达降低房颤易感性和持续时间、心房组织Cx43表达水平、心房组织纤维化标记物表达水平，减轻心房纤维化程度。综上，过表达miR-590-3p能够减轻心房纤维化，降低大鼠的房颤易感性，且通过提高Cx43参与心房重构机制。因此，miR-590-3p可能是AF治疗中一个新的基因治疗靶点。