Exosomes derived from hypertrophic cardiomyocytes induce inflammation in macrophages via miR-155 mediated MAPK pathway.

We report the application of RNA sequencing technology for high-throughput profiling of normal cardiomyocytes-derived and hypertrophic cardiomyocytes- derived exosomes. The miRNA expression profiles were determined by high throughput miRNA sequencing, and 635 differentially expressed miRNAs were found. However, compared with the control group, 7 miRNAs were significantly differentially expressed in exosomes released from Ang II-treated cardiomyocytes. A total of 4 miRNAs were upregulated while 3 were downregulated. We used qRT-PCR to characterize relative expression levels of miR-155 and miR-212-3p to validate the data obtained through miRNA sequencing. The results obtained through qRT-PCR and miRNA sequencing were essentially identical. To elucidate the potential role of miRNAs in hypertrophic cardiomyocytes, the prediction of miRNA targets was performed and 11,637 genes were obtained. To reduce the false positives rate of target gene prediction, only the predicted targets within the 3 databases described above were further analyzed. Finally, 5,477 predicted target genes were selected for further investigation. Our results support the concept that exosomal microRNAs have emerged as important inflammatory response modulators regulating the cardiac hypertrophy.本研究报道了RNA测序技术（RNA sequencing）在正常心肌细胞与肥厚型心肌细胞来源外泌体（exosomes）高通量谱分析中的应用。本研究通过高通量miRNA测序测定了微小RNA（miRNA）的表达谱，共鉴定出635个差异表达的miRNA。然而，与对照组相比，经血管紧张素II（Ang II）处理的心肌细胞所释放的外泌体中，仅有7个miRNA呈现显著差异表达，其中4个miRNA表达上调，3个表达下调。本研究采用实时定量逆转录聚合酶链反应（qRT-PCR）对miR-155与miR-212-3p的相对表达水平进行定量分析，以验证miRNA测序获得的结果，qRT-PCR与miRNA测序所得结果基本一致。为阐明miRNA在肥厚型心肌细胞中的潜在作用，本研究开展了miRNA靶基因预测工作，共获得11637个候选靶基因；为降低靶基因预测的假阳性率，本研究仅对上述3个数据库中的预测靶基因进行后续分析，最终筛选出5477个预测靶基因用于后续研究。本研究结果支持如下观点：外泌体源性miRNA已成为调控心肌肥厚的重要炎症反应调节因子。