Wuhu decoction regulates ROS/AMPK/mTOR pathway-mediated dendritic cells autophagy and pyroptosis for the treatment of respiratory syncytial virus-induced asthma.

Background: Respiratory syncytial virus (RSV) infection is a major trigger of asthma, especially in children, and is associated with oxidative stress and inflammation. Emerging evidence suggests that dendritic cell (DC) pyroptosis and impaired autophagy contribute to asthma pathogenesis. Wuhu decoction (WHD), a traditional Chinese herbal formula, has shown clinical potential in asthma management, but its mechanisms remain unclear. This study aimed to investigate the mechanism by which WHD regulates DCs autophagy and pyroptosis to prevent and treat RSV-induced asthma, as well as its regulatory effect on the reactive oxygen species (ROS)/AMPK/mTOR pathway. Methods: One hundred specific pathogen-free-grade male Bagg Albino/c mice were induced with asthma by inhalation of RSV complexed with ovalbumin (OVA). After successful modeling, the mice were designated into control, model group, WHD low-dose, WHD medium-dose, WHD high-dose, dexamethasone, rapamycin, 3-MA, MCC950 group, and these treatments lasted for 2 weeks. Respiratory responsiveness of mice was measured by plethysmography. Lung tissue pathology changes, goblet cell mucin secretion, and airway collagen deposition were assessed with histology. Flow cytometry detected ROS activity in lung tissue. Transmission electron microscopy examined lung autophagosomes. Western blot determined expression of airway remodeling-related proteins α-smooth muscle actin (α-SMA) and transforming growth factor-β (TGF-β), autophagy-, pyroptosis-, pathway-related proteins in lung tissue DCs. Results: Comparing to controls, asthmatic mice exhibited increased airway responsiveness, peri-bronchial inflammatory cell infiltration, goblet cell hyperplasia, and widespread airway collagen deposition. α-SMA and TGF-β proteins in lung tissue were significantly elevated, and ROS activity in lung tissues was enhanced. DCs autophagy level in lungs was increased and DCs pyroptosis was increased, while p-AMPK/AMPK protein in lung tissue DCs was decreased, and p-mTOR/mTOR protein level was increased in asthmatic mice comparing to controls. Comparing to model mice, medium and high dose of WHD, rapamycin and MCC950 significantly reduced airway responsiveness in asthmatic mice, alleviated airway inflammation, epithelial cell proliferation, and widespread deposition of TGF-β and α-SMA proteins in lung tissues, as well as reduced ROS activity. Furthermore, these interventions further enhanced DCs autophagy, inhibited DCs pyroptosis, promoted p-AMPK expression, and inhibited p-mTOR expression in DCs of lung tissues. Conclusions: WHD may activate DCs autophagy through the ROS/AMPK/mTOR axis, inhibit NLRP3 inflammasome-induced cell pyroptosis, and thus prevent and treat RSV-induced asthma in mice.