MicroRNA-30a Targets ATG5 and Attenuates Airway Fibrosis in Asthma by Suppressing Autophagy

Asthma is the most common chronic disease of childhood, chronic airway inflammation; bronchial tissue fibrosis, is a pathological feature common to children asthma, and an emerging data has indicted that autophagy plays critical roles in airway inflammation and fibrosis-mediated airway remodeling. The aim of this study was to examine whether the antifibrotic effect of epithelial microRNAs (miRNAs) relies on regulating autophagy-mediated airway remodeling and to identify the factors involved and the underlying mechanisms. Our results showed miR-30a were downregulated in children with asthma and ovalbumin (OVA) mouse model in parallel with the upregulation of autophagy-related proteins; moreover, we observed miR-30a inhibited the autophagy by downregulated autophagy-related 5 (ATG5). Then, we observed that overexpression of miR-30a suppressed the fibrogenesis and autophagic flux which was stimulated by interleukin-33 (IL-33) in bronchial epithelial cells. In vivo experiments showed that miR-30a overexpression decreased airway remodeling by decreased autophagy. This study uncovered a previously unrecognized antifibrotic role of miR-30a in asthma, in IL-33-induced lung epithelial cells in vitro, and in a murine model of OVA-induced airway inflammation in vivo and explored the underlying mechanisms.