Allergen induces CD11c⁺ dendritic cell autophagy to aggravate allergic rhinitis through promoting immune imbalance

The level of autophagy in CD11c⁺ dendritic cell (DC) and its contribution to the subsequent immune imbalance are still unclear. The aim of this study was to investigate the role and mechanism of them in promoting the allergic inflammatory response. Nasal mucosa tissues were collected from allergic rhinitis (AR) mice and their control group to detect the expression of LC3II, P62 and ATG5 and CD11c⁺DC autophagy. Different concentration of OVA or the combination of OVA and autophagy inhibitor (3-MA) were used to induce the differentiation of mouse bone marrow-derived DCs (CD11c⁺BMDCs). Differences in LC3II, P62 and ATG5 expression and autophagosome formation were detected. BMDCs in the above groups were cocultured with spleen lymphocytes to detect the proportions of effector T cells and changes in cytokines. OVA-loaded BMDCs were injected intravenously into C57BL/6 mice to develop allergic model. The nasal mucosa of mice in the AR group showed significantly increased LC3II and ATG5 protein expression, whereas showed significantly decreased P62 protein expression. Moreover, LC3II was mainly co-expressed with CD11c⁺ DC markers. In vitro, OVA stimulation induced the increase of autophagosomes and the expression of autophagy-related proteins in BMDCs in a dose-dependent manner, and inhibition of autophagy showed significantly decreased LC3II and ATG5 expression and autophagosome abundance. In addition, OVA-induced BMDC autophagy can affect CD4+T cell differentiation and related cytokine levels, however, the Th1/Th2/Th9/Th17/Treg/Tfh cell immune imbalances were significantly reversed after the addition of 3-MA. Adoptive transfer of OVA-loaded BMDCs could promote the allergic inflammation, while the administration of 3-MA on OVA-loaded BMDCs could significantly reduce the AR inflammation. Overall, our findings demonstrate that allergen can induce CD11c⁺DC autophagy in a dose-dependent manner and promote the immune imbalance of downstream T cells towards a proinflammatory phenotype.