Role of microRNA-21 in airway remodeling in asthmatic mice

Abstract

Objective Airway remodeling is an important pathological feature of asthma.This study is to investigate the role of microRNA-21 (miR-21) in airway remodeling in asthmatic mice. Methods A total of 16 female BALB/c mice were randomly divided into control group and asthma model group.Mice were sensitized and challenged by ovalbumin to establish a murine model of asthma.The mice in the normal control group were intraperitoneally injected with phosphate buffered saline for sensitization and given a phosphate buffered saline inhalation for the challenge.Twenty-four hours after the last aerosol inhalation, lung tissues of mice were sampled and subjectd to Western blot for testing expression of TGFβ type Ⅱ receptor, Smad7, and Collagen Type Ⅰ (COL Ⅰ) in lung tissue of mice of each group.Quantitative real-time PCR was used to test miR-21 expression in lung tissue of mice of each group.Target gene prediction software (TargetScan) was used to predict target gene of miR-21.293T cell was used to conduct dual-luciferase reporter gene assay for verification of miR-21 target gene. Results Compared with control group, asthma group had increased expression of COL Ⅰ protein and miR-21 in lung tissue (t=11.94, P<0.05; t=23.05, P<0.05). Smad7 and TGF-βRⅡ were target genes of miR-21. Conclusion miR-21 down-regulates Smad7, a target gene of miR-21, activates the TGFβ/Smad signaling pathway, and promotes airway remodeling, indicating that miR-21 may be a therapeutic target for the treatment of airway remodeling in asthma. Key words: MicroRNA-21; Target gene; Asthma; Airway remodeling; Mice