Allergen-induced dendritic cell autophagy drives immune imbalance in asthma.

Abstract

The role of autophagy in dendritic cell (DC) maturation and immune balance in asthma remains unclear. This study investigates the involvement of autophagy in DC function and its impact on T cell differentiation in asthma. Peripheral blood mononuclear cells (PBMCs) from asthmatic children and healthy controls were analyzed by flow cytometry to assess DC maturation and T cell subsets. In house dust mite (HDM) -induced asthma mouse models(20 μg per dose, intranasal), we evaluated DC maturation and T cell differentiation. Bone Marrow-Derived Dendritic Cells (BMDCs) from normal and asthmatic mice were stimulated with LPS to assess pro-inflammatory functions. Autophagy in HDM-induced BMDCs was assessed by Western blotting (LC3-II/I, p62, ATG3, ATG7, Beclin-1), immunofluorescence (LC3 puncta and LAMP2), and electron microscopy. Autophagic flux was inferred from LC3-II turnover in the presence of bafilomycin A1 together with p62 dynamics. Autophagy inhibitors (3-MA and bafilomycin A1) were used to examine their effects on DC maturation and T cell differentiation. Asthmatic children exhibited elevated DC maturation markers, which were negatively correlating with lung function (FEV1/FVC ratio), along with imbalances in Th1/Th2 and Th17/Treg ratios. In HDM-induced models, increased DC maturation occurred concurrently with enhanced Th2/Th17 polarization and worsened airway inflammation (higher inflammation scores, elevated serum IgE, increased BALF total counts and eosinophil counts). HDM treatment upregulated autophagy in BMDCs. Autophagy inhibition suppressed DC over-maturation, reduced Th2/Th17 differentiation, and promoted Th1/Treg polarization. Adoptive transfer of HDM-treated BMDCs exacerbated airway inflammation and immune imbalances, which were alleviated by co-treatment with 3-MA. We demonstrate that autophagy-a process with established roles in antigen processing and metabolic reprogramming-drives DC over-maturation and T cell differentiation in asthma. Despite its homeostatic functions, its moderate inhibition restrains DC over-activation and rebalances T-cell responses. Potential dependencies on DC subsets (cDC1/cDC2) and disease stage (acute vs. chronic) warrant further investigation.