Scorpion and centipede alleviates severe asthma through M2 macrophage-derived exosomal miR-30b-5p

Asthma is one of the most common chronic inflammatory diseases. Although the scorpion and centipede (SC) significantly ameliorates asthma and changes exosomal miRNAs, the molecular mechanism is still obscure. Here, we show that SC improves inflammation in asthmatic mice and increases M2 macrophage-derived exosomes (M2Φ-Exos) by promoting M2 macrophage polarization. The M2Φ-Exos remarkably inhibits airway epithelial cell pyroptosis by reducing the expression of NLRP3, caspase-1, and LI-1β and mitochondrial swelling. Furthermore, miR-30b-5p is up-regulated in M2Φ-Exos compared with M1Φ-Exos. Overexpression of miR-30b-5p in M2Φ-Exos prevents airway epithelial cell pyroptosis, while down-regulation of miR-30b-5p promotes pyroptosis. We also uncover that pyroptosis is increased in asthmatic mice, while SC blocks pyroptosis. Moreover, miR-30b-5p overexpressed M2Φ-Exos further enhances the ameliorative effect of SC, which significantly down-regulates IRF7 expression. Our results collectively reveal that M2Φ-Exos induced by SC could carry miR-30b-5p to mitigate severe asthma by inhibiting airway epithelial cell pyroptosis. Most importantly, our findings may provide a potential clinical application of M2Φ-Exos for treating severe asthma.