Overexpression of microRNA-21 and microRNA-126 in the patients of bronchial asthma

MicroRNAs are implicated in an increasing number of diseases and health complications, including asthma. Previous studies have suggested roles for microRNA-21 (miR-21) and microRNA-126 (miR-126) in asthma, although these relationships are incompletely understood. The aim of this study was to further assess the relationship between miR-21, miR-126 and the occurrence and treatment of allergic asthma. Quantitative real-time PCR analyzed expression levels of miR-21 and miR-126 in bronchial epidermal cells from asthma patients treated with (treatment group, n = 19) or without (non-treatment group, n = 16) inhaled corticosteroids or from non-asthmatic healthy individuals (normal group, n = 12). Bronchial epidermal cells were cultured in vitro to determine if there was a relationship between IL-13 and miR-21 and miR-126 expression. Compared to the normal group, miR-21 and miR-126 expression was significantly upregulated in asthma patients regardless of treatment. miR-21 and miR-126 expression was significantly higher in the non-treatment group than the treatment group (P < 0.05). In vitro, miR-21 and miR-126 expression increased in bronchial epidermal cells with increasing IL-13 concentration. Because upregulation of miR-126 and miR-21 were associated with occurrence and therapy of allergic asthma, they may be indices of therapeutic effect that are valuable for the evaluation for asthma treatment.