背景:22q11.2缺失综合征(22q11.2DS)是一种微缺失综合征,具有高度可变的表型表现,即使大多数患者呈现典型的3Mb微缺失,通常影响相同的~106个基因。受这种缺失影响的基因之一是DGCR8,它在miRNA生物发生中起着至关重要的作用。因此,由于这种微缺失导致的DGCR8单倍体不足可以改变涉及一系列生物学过程的几种miRNA表达的调节。
结果:在这项研究中,我们使用下一代测序评估了12名具有典型22q11DS的个体和12名健康匹配对照者外周血中的miRNA谱.我们使用DESeq2软件包进行差异基因表达分析,并使用DIANA-miTED数据集来验证差异表达的miRNA在其他组织中的表达。我们使用miRWalk预测差异表达miRNA的靶基因。这里,我们描述了与对照组相比,患者中两种差异表达的miRNA:hsa-miR-1304-3p,位于22q11.2区域之外,在患者中上调,和hsa-miR-185-5p,位于22q11.2地区,显示下调。在22q11DS患者中经常受影响的组织中观察到miR-185-5p的表达,以前的研究报道了其在22q11DS患者中的下调。hsa-miR-1304-3p在血液中低表达,因此,需要更多的验证,尽管使用敏感的技术使我们能够识别患者和对照组之间的表达差异。
结论:因此,miR-185-5p的低表达可能与22q11.2缺失和DGCR8单倍体不足有关,导致22q11.2DS患者的表型后果,而hsa-miR-1304-3p的较高表达可能与巴西人群的异质性背景导致的个体基因组差异有关。
BACKGROUND: The 22q11.2 deletion syndrome (22q11.2DS) is a microdeletion syndrome with highly variable phenotypic manifestations, even though most patients present the typical 3 Mb microdeletion, usually affecting the same ~ 106 genes. One of the genes affected by this deletion is DGCR8, which plays a crucial role in miRNA biogenesis. Therefore, the
haploinsufficiency of DGCR8 due to this microdeletion can alter the modulation of the expression of several miRNAs involved in a range of biological processes.
RESULTS: In this study, we used next-generation sequencing to evaluate the miRNAs profiles in the peripheral blood of 12 individuals with typical 22q11DS compared to 12 healthy matched controls. We used the DESeq2 package for differential gene expression analysis and the DIANA-miTED dataset to verify the expression of differentially expressed miRNAs in other tissues. We used miRWalk to predict the target genes of differentially expressed miRNAs. Here, we described two differentially expressed miRNAs in patients compared to controls: hsa-miR-1304-3p, located outside the 22q11.2 region, upregulated in patients, and hsa-miR-185-5p, located in the 22q11.2 region, which showed downregulation. Expression of miR-185-5p is observed in tissues frequently affected in patients with 22q11DS, and previous studies have reported its downregulation in individuals with 22q11DS. hsa-miR-1304-3p has low expression in blood and, thus, needs more validation, though using a sensitive technology allowed us to identify differences in expression between patients and controls.
CONCLUSIONS: Thus, lower expression of miR-185-5p can be related to the 22q11.2 deletion and DGCR8
haploinsufficiency, leading to phenotypic consequences in 22q11.2DS patients, while higher expression of hsa-miR-1304-3p might be related to individual genomic variances due to the heterogeneous background of the Brazilian population.