Martínez Cristina, Rodiño-Janeiro Bruno K, Lobo Beatriz, Stanifer Megan L, Klaus Bernd, Granzow Martin, González-Castro Ana M, Salvo-Romero Eloisa, Alonso-Cotoner Carmen, Pigrau Marc, Roeth Ralph, Rappold Gudrun, Huber Wolfgang, González-Silos Rosa, Lorenzo Justo, de Torres Inés, Azpiroz Fernando, Boulant Steeve, Vicario María, Niesler Beate, Santos Javier
Department of Human Molecular Genetics, Institute of Human Genetics, University of Heidelberg, Heidelberg, Germany.
Digestive System Research Unit, Institut de Recerca Vall d'Hebron, Barcelona, Spain.
Gut. 2017 Sep;66(9):1537-1538. doi: 10.1136/gutjnl-2016-311477. Epub 2017 Jan 12.
Micro-RNAs (miRNAs) play a crucial role in controlling intestinal epithelial barrier function partly by modulating the expression of tight junction (TJ) proteins. We have previously shown differential messenger RNA (mRNA) expression correlated with ultrastructural abnormalities of the epithelial barrier in patients with diarrhoea-predominant IBS (IBS-D). However, the participation of miRNAs in these differential mRNA-associated findings remains to be established. Our aims were (1) to identify miRNAs differentially expressed in the small bowel mucosa of patients with IBS-D and (2) to explore putative target genes specifically involved in epithelial barrier function that are controlled by specific dysregulated IBS-D miRNAs.
Healthy controls and patients meeting Rome III IBS-D criteria were studied. Intestinal tissue samples were analysed to identify potential candidates by: (a) miRNA-mRNA profiling; (b) miRNA-mRNA pairing analysis to assess the co-expression profile of miRNA-mRNA pairs; (c) pathway analysis and upstream regulator identification; (d) miRNA and target mRNA validation. Candidate miRNA-mRNA pairs were functionally assessed in intestinal epithelial cells.
IBS-D samples showed distinct miRNA and mRNA profiles compared with healthy controls. TJ signalling was associated with the IBS-D transcriptional profile. Further validation of selected genes showed consistent upregulation in 75% of genes involved in epithelial barrier function. Bioinformatic analysis of putative miRNA binding sites identified hsa-miR-125b-5p and hsa-miR-16 as regulating expression of the TJ genes (cingulin) and (claudin-2), respectively. Consistently, protein expression of CGN and CLDN2 was upregulated in IBS-D, while the respective targeting miRNAs were downregulated. In addition, bowel dysfunction, perceived stress and depression and number of mast cells correlated with the expression of hsa-miR-125b-5p and hsa-miR-16 and their respective target proteins.
Modulation of the intestinal epithelial barrier function in IBS-D involves both transcriptional and post-transcriptional mechanisms. These molecular mechanisms include miRNAs as master regulators in controlling the expression of TJ proteins and are associated with major clinical symptoms.
微小RNA（miRNA）在控制肠道上皮屏障功能中发挥关键作用，部分是通过调节紧密连接（TJ）蛋白的表达来实现的。我们之前已经表明，腹泻型肠易激综合征（IBS-D）患者的信使核糖核酸（mRNA）表达差异与上皮屏障的超微结构异常相关。然而，miRNA在这些与mRNA相关的差异结果中的参与情况仍有待确定。我们的目的是：（1）鉴定IBS-D患者小肠黏膜中差异表达的miRNA；（2）探索由特定失调的IBS-D miRNA控制的、具体参与上皮屏障功能的假定靶基因。
对符合罗马III IBS-D标准的健康对照者和患者进行研究。通过以下方法分析肠道组织样本以确定潜在候选物：（a）miRNA-mRNA谱分析；（b）miRNA-mRNA配对分析以评估miRNA-mRNA对的共表达谱；（c）通路分析和上游调节因子鉴定；（d）miRNA和靶mRNA验证。在肠道上皮细胞中对候选miRNA-mRNA对进行功能评估。
与健康对照相比，IBS-D样本显示出不同的miRNA和mRNA谱。TJ信号传导与IBS-D转录谱相关。对选定基因的进一步验证显示，参与上皮屏障功能的基因中有75%持续上调。对假定的miRNA结合位点进行生物信息学分析，确定hsa-miR-125b-5p和hsa-miR-16分别调节TJ基因（cingulin）和（claudin-2）的表达。一致的是，IBS-D中CGN和CLDN2的蛋白表达上调，而各自的靶向miRNA下调。此外，肠道功能障碍、感知到的压力和抑郁以及肥大细胞数量与hsa-miR-
