Background:Transcatheter aortic valve replacement (TAVR) is a well-established treatment option for high- and intermediate-risk patients with severe symptomatic aortic valve stenosis. A majority of patients exhibit improvements in left ventricular ejection fraction (LVEF) after TAVR in response to TAVR-associated afterload reduction. However, a specific role for circulating microRNAs (miRNAs) in the improvement of cardiac function for patients after TAVR has not yet been investigated. Here, we profiled the differential expression of miRNAs in circulating extracellular vesicles (EVs) in patients after TAVR and, in particular, the novel role of circulating miR-122-5p in cardiomyocytes.Methods:Circulating EV-associated miRNAs were investigated by use of an unbiased Taqman-based human miRNA array. Several EV miRNAs (miR-122-5p, miR-26a, miR-192, miR-483-5p, miR-720, miR-885-5p, and miR-1274) were significantly deregulated in patients with aortic valve stenosis at day 7 after TAVR compared with the preprocedural levels in patients without LVEF improvement. The higher levels of miR-122-5p were negatively correlated with LVEF improvement at both day 7 (r=−0.264 and P=0.015) and 6 months (r=−0.328 and P=0.0018) after TAVR.Results:Using of patient-derived samples and a murine aortic valve stenosis model, we observed that the expression of miR-122-5p correlates negatively with cardiac function, which is associated with LVEF. Mice with graded wire injury–induced aortic valve stenosis demonstrated a higher level of miR-122-5p, which was related to cardiomyocyte dysfunction. Murine ex vivo experiments revealed that miR-122-5p is highly enriched in endothelial cells compared with cardiomyocytes. Coculture experiments, copy-number analysis, and fluorescence microscopy with Cy3-labeled miR-122-5p demonstrated that miR-122-5p can be shuttled through large EVs from endothelial cells into cardiomyocytes. Gain- and loss-of-function experiments suggested that EV-mediated shuttling of miR-122-5p increases the level of miR-122-5p in recipient cardiomyocytes. Mechanistically, mass spectrometry, miRNA pulldown, electrophoretic mobility shift assay, and RNA immunoprecipitation experiments confirmed that miR-122-5p interacts with the RNA-binding protein hnRNPU (heterogeneous nuclear ribonucleoprotein U) in a sequence-specific manner to encapsulate miR-122-5p into large EVs. On shuttling, miR-122-5p reduces the expression of the antiapoptotic gene BCL2 by binding to its 3′ untranslated region to inhibit its translation, thereby decreasing the viability of target cardiomyocytes.Conclusions:Increased levels of circulating proapoptotic EV-incorporated miR-122-5p are associated with reduced LVEF after TAVR. EV shuttling of miR-122-5p regulates the viability and apoptosis of cardiomyocytes in a BCL2-dependent manner.

中文翻译：

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循环 MicroRNA-122-5p 与经导管主动脉瓣置换术后左心室功能缺乏改善有关，并通过细胞外囊泡调节心肌细胞的活力


背景：经导管主动脉瓣置换术（TAVR）是针对患有严重症状性主动脉瓣狭窄的高风险和中风险患者的一种成熟的治疗选择。大多数患者在 TAVR 后表现出左心室射血分数 (LVEF) 的改善，以响应 TAVR 相关的后负荷减少。然而，循环 microRNA (miRNA) 在改善 TAVR 后患者心功能方面的具体作用尚未得到研究。在这里，我们分析了 TAVR 后患者循环细胞外囊泡 (EV) 中 miRNA 的差异表达，特别是循环 miR-122-5p 在心肌细胞中的新作用。方法：通过使用基于 Taqman 的无偏人类 miRNA 阵列。主动脉瓣狭窄患者的几种 EV miRNA（miR-122-5p、miR-26a、miR-192、miR-483-5p、miR-720、miR-885-5p 和 miR-1274）在白天显着失调7 TAVR 后与术前水平相比，LVEF 未改善的患者。 TAVR 后第 7 天（ r =−0.264 和P =0.015）和 6 个月（ r =−0.328 和P =0.0018）时，较高水平的 miR-122-5p 与 LVEF 改善呈负相关。 结果：患者的使用通过对衍生样本和小鼠主动脉瓣狭窄模型的研究，我们观察到 miR-122-5p 的表达与心功能呈负相关，而心功能又与 LVEF 相关。分级金属丝损伤引起的主动脉瓣狭窄的小鼠表现出较高水平的 miR-122-5p，这与心肌细胞功能障碍有关。小鼠离体实验表明，与心肌细胞相比，miR-122-5p在内皮细胞中高度富集。 使用 Cy3 标记的 miR-122-5p 进行的共培养实验、拷贝数分析和荧光显微镜检查表明，miR-122-5p 可以通过大型 EV 从内皮细胞转运到心肌细胞。功能获得和丧失实验表明，EV介导的miR-122-5p穿梭增加了受体心肌细胞中miR-122-5p的水平。从机制上讲，质谱分析、miRNA Pulldown、电泳迁移率变动分析和 RNA 免疫沉淀实验证实 miR-122-5p 以序列特异性方式与 RNA 结合蛋白 hnRNPU（异质核核糖核蛋白 U）相互作用，从而封装 miR-122-5p。大型电动汽车 5 便士。在穿梭过程中，miR-122-5p 通过结合抗凋亡基因BCL2的 3' 非翻译区来抑制其翻译，从而降低抗凋亡基因 BCL2 的表达，从而降低靶心肌细胞的活力。 结论：循环中 EV 掺入的促凋亡 miR-122 水平增加-5p 与 TAVR 后 LVEF 降低相关。 miR-122-5p 的 EV 穿梭以 BCL2 依赖性方式调节心肌细胞的活力和凋亡。