Department of Respiratory Medicine, Ghent University Hospital, Ghent, Belgium.
Am J Respir Crit Care Med. 2011 Apr 1;183(7):898-906. doi: 10.1164/rccm.201002-0304OC. Epub 2010 Oct 29.
Chronic obstructive pulmonary disease (COPD) is characterized by progressive inflammation in the airways and lungs combined with disturbed homeostatic functions of pulmonary cells. MicroRNAs (miRNAs) have the ability to regulate these processes by interfering with gene transcription and translation.
We aimed to identify miRNA expression in induced sputum and examined whether the expression of miRNAs differed between patients with COPD and subjects without airflow limitation.
Expression of 627 miRNAs was evaluated in induced sputum supernatant of 32 subjects by stem-loop reverse transcription-quantitative polymerase chain reaction. Differentially expressed miRNAs were validated in an independent replication cohort of 41 subjects. Enrichment of miRNA target genes was identified by in silico analysis. Protein expression of target genes was determined by ELISA.
Thirty-four miRNAs were differentially expressed between never-smokers and current smokers without airflow limitation in the screening cohort. Eight miRNAs were expressed at a significantly lower level in current-smoking patients with COPD compared with never-smokers without airflow limitation. Reduced expression of let-7c and miR-125b in patients with COPD compared with healthy subjects was confirmed in the validation cohort. Target genes of let-7c were significantly enriched in the sputum of patients with severe COPD. The concentration of tumor necrosis factor receptor type II (TNFR-II, implicated in COPD pathogenesis and a predicted target gene of let-7c) was inversely correlated with the sputum levels of let-7c .
let-7c is significantly reduced in the sputum of currently smoking patients with COPD and is associated with increased expression of TNFR-II.
慢性阻塞性肺疾病（COPD）的特征是气道和肺部的进行性炎症，同时伴有肺细胞稳态功能紊乱。microRNAs（miRNAs）通过干扰基因转录和翻译，具有调节这些过程的能力。
我们旨在鉴定诱导痰中的 miRNA 表达，并检查 COPD 患者和无气流受限患者之间 miRNA 的表达是否存在差异。
通过茎环反转录定量聚合酶链反应评估 32 例受试者诱导痰上清液中 627 种 miRNA 的表达。在一个由 41 例受试者组成的独立复制队列中验证差异表达的 miRNA。通过计算机分析鉴定 miRNA 靶基因的富集。通过 ELISA 测定靶基因的蛋白表达。
在筛选队列中，从不吸烟者和无气流限制的当前吸烟者之间有 34 种 miRNA 存在差异表达。与无气流限制的从不吸烟者相比，COPD 患者的当前吸烟者中有 8 种 miRNA 的表达水平明显降低。在验证队列中，COPD 患者与健康受试者相比，let-7c 和 miR-125b 的表达明显降低。let-7c 的靶基因在严重 COPD 患者的痰液中明显富集。COPD 发病机制中涉及的肿瘤坏死因子受体 II（TNFR-II，是 let-7c 的预测靶基因）的浓度与痰液中 let-7c 的水平呈负相关。
在 COPD 患者当前吸烟者的痰液中，let-7c 的表达明显降低，与 TNFR-II 的表达增加有关。
