Molecular mechanism of Mir-27B-3P carried by bronchial epithelial cell-derived extracellular vesicle in airway inflammation in asthmatic mice

Asthma represents a classic respiratory disorder marked by chronic inflammation in the airways. This study aims to demonstrate the mechanism of bronchial epithelial cell-derived extracellular vesicles (BEC-EVs) carrying miR-27b-3p in airway inflammation in asthmatic mice, providing potential therapeutic targets for asthma. BECs and their EVs were isolated from mice and characterized. Asthmatic mouse models were established using ovalbumin and neutrophils were isolated. Histopathological changes and collagen deposition in lung tissues were observed. The levels of proinflammatory factors in the BALF and neutrophils were measured by ELISA. dsDNA levels in BALF or neutrophils were quantified using a dsDNA kit. Expression of cy3-labeled miR-27b-3p in neutrophils was detected. The levels of miR-27b-3p, ZMAT3, FGF1, Cit-H3, and MPO in lung tissues and cells were detected by RT-qPCR and Western blot. The binding relationships between miR-27b-3p and ZMAT3 and between ZMAT3 and FGF1 were verified. Combined experiments were used to validate the molecular mechanism by which BEC-EVs promote NET formation and regulate airway inflammation in asthmatic mice via the miR-27b-3p/ZMAT3/FGF1 axis. After BEC-EVs treatment, peribronchial inflammatory cell infiltration and collagen deposition were aggravated, and Cit-H3, MPO, and dsDNA were increased in OVA-induced mice, indicating exacerbated airway inflammation and promoted NET formation. BEC-EVs delivered miR-27b-3p to neutrophils and upregulated miR-27b-3p expression, which inhibited ZMAT3 to promote FGF1 expression. ZMAT3 overexpression or FGF1 knockdown partially reversed the BEC-EVs-induced NET formation. BEC-EVs promote NET formation and further aggravate airway inflammation in OVA-induced asthmatic mice by delivering miR-27b-3p to neutrophils, inhibiting ZMAT3, and promoting FGF1 expression.