Department of Gastroenterology, The Affiliated Hospital of Guangdong Medical College, Zhanjiang, Guangdong, People's Republic of China.
PLoS One. 2012;7(12):e52782. doi: 10.1371/journal.pone.0052782. Epub 2012 Dec 28.
MicroRNAs (miRNAs) are important post-transcriptional regulators. Altered expression of miRNAs has recently demonstrated association with human ulcerative colitis (UC). In this study, we attempted to elucidate the roles of miR-126 in the pathogenesis of UC.
Expression of miR-126, miR-21, miR-375 and the potential targets NF-κB inhibitor alpha (IκBα, IKBA or NFKBIA), Polo-like kinase 2 (PLK2) and v-Crk sarcoma virus CT10 oncogene homolog (CRK) were assessed in 52 colonic biopsies from patients with active UC, inactive UC, irritable bowel syndrome (IBS) and from healthy subjects by quantitative RT-PCR and immunofluorescence analyses. Regulation of gene expression by miR-126 was assessed using luciferase reporter construct assays and specific miRNA mimic transfection.
We found that the expression of miR-126 and miR-21 were significantly increased in active UC group compared to the inactive UC, IBS and healthy control groups (P<0.05). In contrast, the expression of IKBA mRNA and protein was remarkably decreased in the active UC group compared with the other three groups (P<0.05). The expression of miR-126 and IKBA mRNA were inversely correlated in active UC patients (P<0.05). However the expression of miR-375, PLK2 and CRK showed no difference between each group. Furthermore, we demonstrate that endogenous miR-126 and exogenous miR-126 mimic can inhibit IκBα expression. Finally, mutating the miR-126 binding site of the IKBA 3'-UTR reporter construct restored reporter gene expression.
miR-126 may play roles in UC inflammatory activity by down-regulating the expression of IKBA, an important inhibitor of NF-κB signaling pathway.
MicroRNAs（miRNAs）是重要的转录后调控因子。miRNAs 的表达改变最近被证明与人类溃疡性结肠炎（UC）有关。在这项研究中，我们试图阐明 miR-126 在 UC 发病机制中的作用。
通过定量 RT-PCR 和免疫荧光分析，评估了 52 例来自活动期 UC、缓解期 UC、肠易激综合征（IBS）和健康对照患者的结肠活检组织中 miR-126、miR-21、miR-375 和潜在靶点 NF-κB 抑制剂α（IκBα、IKBA 或 NFKBIA）、Polo 样激酶 2（PLK2）和 v-Crk 肉瘤病毒 CT10 癌基因同源物（CRK）的表达。通过荧光素酶报告基因构建体测定和特异性 miRNA 模拟转染评估基因表达的调控。
我们发现，与缓解期 UC、IBS 和健康对照组相比，活动期 UC 组 miR-126 和 miR-21 的表达显著增加（P<0.05）。相比之下，在活动期 UC 组中 IKBA mRNA 和蛋白的表达明显降低（P<0.05）。活动期 UC 患者中 miR-126 和 IKBA mRNA 的表达呈负相关（P<0.05）。然而，miR-375、PLK2 和 CRK 的表达在各组之间没有差异。此外，我们证明内源性 miR-126 和外源性 miR-126 模拟物可以抑制 IκBα 的表达。最后，突变 IKBA 3'-UTR 报告基因构建体中的 miR-126 结合位点恢复了报告基因的表达。
miR-126 可能通过下调 NF-κB 信号通路的重要抑制剂 IKBA 的表达在 UC 炎症活性中发挥作用。
