Department of Cardiology, Clinical Sciences, Skåne University Hospital, Lund University, BMC D12, S?gatan 19, 221 84, Lund, Sweden.
Prevention of Organ Failure (PROOF) Centre of Excellence, 1190 Hornby Street, Vancouver, British Columbia, V6Z 2K5. Canada.
Cardiovasc Res. 2017 Apr 1;113(5):440-452. doi: 10.1093/cvr/cvw244.
Exosome-mediated microRNA transfer is a recently discovered mode of cell-to-cell communication, in which microRNAs act as paracrine molecules, exerting their regulatory effects in recipient cells. T cells and endothelial cells are two main players in the mechanism of acute cellular cardiac rejection. The aim of this study was to investigate the role of exosomal microRNAs in the crosstalk between T cells and endothelial cells and its implications for the molecular mechanisms that drive acute cellular rejection in heart transplantation.
Exosomes isolated from serum samples of heart transplant patients with and without acute cardiac allograft rejection were profiled and showed enrichment of miR-142-3p, miR-92a-3p, miR-339-3p and miR-21-5p. Treatment of endothelial cells with the respected serum exosomes resulted the increased of miR-142-3p level in endothelial cells. Using T cells isolated from healthy donors and activated with either anti-CD3/CD28 antibody or IL-2/PHA, we could show that miR-142-3p is released from activated cells, is contained in exosomes and can be transferred to human vascular endothelial cells in vitro. Transcriptome analysis of endothelial cells treated with activated T cell supernatant with or without exosomes was used to identify mRNA targets of transferred miR-142-3-p. Overexpression of miR-142-3p in endothelial cells resulted in a significant down-regulation of RAB11FIP2, and interaction of miR-142-3p with its predicted target site was confirmed with a reporter assay. Moreover, treatment of endothelial cells with serum exosomes from heart transplant patients with acute cellular rejection resulted in down-regulation of RAB11FIP2 expression and increase in vascular endothelial permeability.
We have identified a novel mechanism whereby miR-142-3p, a microRNA enriched in exosomes during acute cellular rejection, is transferred to endothelial cells and compromises endothelial barrier function via down-regulation of RAB11FIP2. This study sheds new light on the interaction between host immune system and cardiac allograft endothelium during acute cellular rejection.
外泌体介导的 microRNA 转移是一种最近发现的细胞间通讯模式，其中 microRNA 作为旁分泌分子，在受体细胞中发挥其调节作用。T 细胞和内皮细胞是急性细胞性心脏排斥反应机制中的两个主要参与者。本研究旨在探讨外泌体 microRNA 在 T 细胞和内皮细胞之间相互作用中的作用及其对驱动心脏移植中急性细胞性排斥反应的分子机制的影响。
从有和没有急性心脏移植物排斥的心脏移植患者的血清样本中分离出外泌体进行分析，结果显示 miR-142-3p、miR-92a-3p、miR-339-3p 和 miR-21-5p 富集。用相应的血清外泌体处理内皮细胞，可使内皮细胞中 miR-142-3p 水平升高。使用从健康供体分离的 T 细胞，并用抗 CD3/CD28 抗体或 IL-2/PHA 激活，我们可以证明 miR-142-3p 从激活的细胞中释放出来，包含在外泌体中，并可以在体外转移到人血管内皮细胞中。用含有或不含有外泌体的激活 T 细胞上清液处理内皮细胞的转录组分析用于鉴定转移的 miR-142-3p 的 mRNA 靶标。在内皮细胞中转染 miR-142-3p 可显著下调 RAB11FIP2 的表达，通过报告基因实验证实了 miR-142-3p 与其预测靶位点的相互作用。此外，用急性细胞性排斥的心脏移植患者的血清外泌体处理内皮细胞，导致 RAB11FIP2 表达下调和血管内皮通透性增加。
我们已经确定了一种新的机制，即在急性细胞性排斥期间富含外泌体的 microRNA miR-142-3p 转移到内皮细胞，并通过下调 RAB11FIP2 来破坏内皮屏障功能。本研究为宿主免疫系统和心脏移植物内皮细胞在急性细胞性排斥反应期间的相互作用提供了新的认识。
