Clinical Medical Research Center, Shenzhen Pingshan People's Hospital, Shenzhen, Guangdong 518118, PR China; Key Laboratory of Laboratory Medical Diagnostics of Education Ministry, Chongqiong Medical University, Chongqing 400016, PR China.
Gene. 2013 Nov 10;530(2):278-86. doi: 10.1016/j.gene.2013.07.055. Epub 2013 Aug 8.
Given the important roles of miRNAs in post-transcriptional regulation and its implications for the development of immune tissues and cells, characterization of miRNAs promotes us to uncover the molecular mechanisms underlying the pathway of trisomic chromosome 21 that disrupts the disomic genes expression and immunological defects related to Down syndrome (DS). In the present study, we analyzed global changes and chromosome distribution characteristics of miRNAs expression in lymphocytes from children with trisomy 21 by means of the Illumina high-throughput sequencing technology. Two small libraries were constructed using pool RNA of normal and DS children. The results have been further validated by stem-loop quantitative RT-PCR. Comparison between DS and normal profiles revealed that most of identified miRNAs were expressed at similar levels. The chromosome 21 that contributes to the abundantly expressed miRNAs was small, and not all Hsa21-derived miRNAs were over-expressed with ratios significantly ≥ 1.5 in Down syndrome children lymphocytes. Based on the deep sequencing technology, 108 novel candidate miRNAs have been identified, and 2 of them were derived from human chromosome 21. For the 114 significantly differentially expressed miRNAs, function annotation of target genes indicated that a set of highly abundantly and significantly differentially expressed miRNAs were involved in hematopoietic or lymphoid organ development, thymus development, and T/B cell differentiation and activation. Our results indicated that these abnormally expressed miRNAs might be associated with the mechanisms that trisomy 21 results in dysregulation of disomic genes and involved in the immunological defects seen in DS.
鉴于 miRNAs 在转录后调控中的重要作用及其对免疫组织和细胞发育的影响，对 miRNAs 的特征进行分析有助于我们揭示导致 21 三体染色体的分子机制，该机制破坏了二倍体基因的表达，并与唐氏综合征（DS）相关的免疫缺陷有关。在本研究中，我们通过高通量测序技术分析了唐氏综合征患儿淋巴细胞中 miRNAs 表达的全局变化和染色体分布特征。使用正常和 DS 患儿的混合 RNA 构建了两个小文库。通过茎环定量 RT-PCR 进一步验证了结果。DS 和正常图谱之间的比较表明，大多数鉴定出的 miRNAs 以相似的水平表达。导致丰富表达 miRNAs 的 21 号染色体较小，并非所有源自 Hsa21 的 miRNA 在唐氏综合征患儿的淋巴细胞中都以显著比例≥1.5 过表达。基于深度测序技术，已鉴定出 108 个新的候选 miRNA，其中 2 个源自人类 21 号染色体。对于 114 个显著差异表达的 miRNAs，靶基因的功能注释表明，一组高度丰富和显著差异表达的 miRNAs 参与了造血或淋巴器官发育、胸腺发育以及 T/B 细胞分化和激活。我们的研究结果表明，这些异常表达的 miRNAs 可能与 21 三体导致二倍体基因失调的机制有关，并与 DS 中观察到的免疫缺陷有关。
