Abstract:

Objective　To observe the expression features of peripheral blood microRNA（miR）-126 in children with asthma and to investigate the influence of miR-126 downregulation on release of interleukin（IL）-4 in mast cells and its possible mechanism. Methods　The peripheral blood of healthy subjects（control group） and astham children（asthma group） were enrolled. The asthma group included 6 children who were treated in Nanjing Children’s Hospital from September to December of 2015. The levels of serum miR-126 were measured in both groups by quantitative real-time polymerase chain reaction（RT-PCR）. After stimulation with lipopolysaccharide（LPS） on P815，miR-126 expression was detected by RT-PCR. P815 were transfected with miR-126 negative control（negative control group） and miR-126 inhibitor（miR-126 inhibitor group） respectively. The levels of IL-4 in supernatants were detect by ELISA，and the levels of phosphorylated P38 were detected by Western Blot in two groups. Results    The levels of peripheral blood miR-126 in asthma group were significantly higher than those in control group（P＜0.05）. In LPS stimulated P815，miR-126 expression increased（P＜0.05）. The levels of IL-4 and phosphorylated P38 in the miR-126 inhibitor group were lower than those in the negative control group，with statistical significance（P＜0.05）. Conclusion    The expression of peripheral blood miR-126 increases in asthma children. Down-regulation of miR-126  may suppress IL-4 release from mast cells by reducing the expression of phosphorylated P38.

Key words: miR-126, asthma, child, mast cell, IL-4

摘要：

目的　观察microRNA（miR）-126在哮喘患儿外周血中的表达特点，检测其下调对肥大细胞白介素（IL）-4分泌的影响及可能机制。方法　以2015年9～12月在南京医科大学附属南京儿童医院哮喘专科门诊就诊的哮喘患儿6例作为观察组，收集同期健康体检儿童作为对照组。应用实时荧光定量聚合酶链反应（RT-PCR）方法检测2组外周血miR-126的表达差异。采用RT-PCR检测小鼠肥大细胞株（P815）中miR-126的变化。将P815细胞分别转染miR-126 阴性对照序列（阴性对照组）及 miR-126抑制物（miR-126下调组），应用酶联免疫吸附实验（ELISA）检测2组细胞上清IL-4水平，应用免疫印迹法（Western Blot）验证2组细胞磷酸化P38水平。结果　哮喘组外周血miR-126水平显著高于对照组（P＜0.05）。在细胞水平的研究发现，脂多糖（LPS）刺激后P815中miR-126表达量增加（P＜0.05）。而miR-126下调组的IL-4及磷酸化P38水平均低于阴性对照组，差异均有统计学意义（P＜0.05）。结论　miR-126在哮喘患儿外周血表达升高。下调miR-126可能通过减少磷酸化P38蛋白表达抑制肥大细胞IL-4分泌。

关键词: miR-126, 哮喘, 儿童, 肥大细胞, 白介素-4