ABSTRACT

To translate circulating microRNAs (miRNAs) into the clinic, a deeper understanding of the factors affecting their expression is needed. In this study, we explored the features affecting the expression of miRNAs and their genetic regulation using the expression data of 103 miRNAs obtained by qPCR in the platelet-poor plasma of 104 subjects. The principal components (PCs) of the expression of the miRNAs were associated with technical and biological features (e.g., synthetic controls or sex) and with blood cell counts. Also, the associations with proximal genetics variants were analysed. We found that haemolysis marker (dCt hsa-miR-23a-3p-hsa-miR-451a) was correlated strongly (β = 0.84, p = 2.07x10⁻²⁹) with the second PC, which explained 10.1% of the overall variability. Thus, we identified haemolysis as a source of variability for miRNA expression even in mild hemolyzed samples (haemolysis marker dCt <5). In addition to hsa-miR-23a-3p and hsa-miR-451a, the miRNAs most stable and most susceptible to haemolysis were identified. Then, we discovered that the expression of miRNAs in platelet-poor plasma was not biased by any blood cell count, and thus, our results supported their role as biomarkers of tissue-specific conditions. Finally, we identified 1,323 genetic variants that corresponded to 158 miRNA expression quantitative trait loci for 14 miRNAs (FDR <0.2), which were enriched in promoter regions (p = 0.03). This enrichment corresponded to a range of specific tissues (e.g., breast or fat) although not to blood tissue, supporting the concept that the expression of circulating miRNAs is under the genetic control of different tissues.

摘要

要将循环微RNA（miRNA）转换到临床，需要对影响其表达的因素有更深入的了解。在这项研究中，我们使用104位受试者的贫血小板血浆中通过qPCR获得的103条miRNA的表达数据，探索了影响miRNA表达的特征及其遗传调控。miRNA表达的主要成分（PC）与技术和生物学特征（例如，合成对照或性别）以及血细胞计数有关。此外，分析了与近端遗传变异的关联。我们发现溶血标志物（dCt hsa-miR-23a-3p-hsa-miR-451a）密切相关（β= 0.84，p = 2.07x10 ^-29）与第二台PC一起使用，它解释了总体差异的10.1％。因此，我们确定溶血是miRNA表达变异的来源，即使在轻度溶血的样品中（溶血标记dCt <5）。除了hsa-miR-23a-3p和hsa-miR-451a，还鉴定出最稳定，最易溶血的miRNA。然后，我们发现贫血血浆中的miRNA表达不受任何血细胞计数的影响，因此，我们的结果支持了它们作为组织特异性疾病的生物标志物的作用。最后，我们确定了1,323个遗传变异，对应于14个miRNA的158个miRNA表达定量性状位点（FDR <0.2），它们富含启动子区域（p = 0.03）。这种富集对应于一定范围的特定组织（例如，乳房或脂肪），但不对应于血液组织，