IL-17A deficiency alleviates PM-induced allergic asthma by suppressing Th17 cell secretion cytokines and mucus overproduction

Abstract

Abstract Particulate matter (PM) aggravates airway and lung inflammatory response in allergic asthma by directly inducing Th17 cells to secrete Th17 cell-associated inflammatory factors and chemokines. IL-17A is a key Th17 cell secretion pro-inflammatory cytokine. In this study, we investigated the role of IL-17A in PM-induced allergic asthma in mice. 7–8 weeks old wild type (WT) mice, and similarly IL-17A knockout (KO) mice, were divided into four experimental groups (healthy control, PM only, OVA only, OVA+PM treatment groups) and treated accordingly. Inflammatory cell and eosinophil infiltration were increased in the PM-induced WT mice compared to WT healthy control, but were decreased in KO mice compared to PM-induced WT mice. Among toll-like receptors (TLRs) that play an important role in innate immune response, TLR2/4/7 expression was significantly increased in PM-induced WT mice, but was reduced in KO mice. Furthermore, we observed decrease in mRNA expression of IL-13, IL-17A, IL-22, and TGF-β among cytokines of Th2 and Th17 cells in KO mice. PM-induced WT mice facilitated the overt histopathological symptoms of allergic asthma such as mucus overproduction and goblet cell hyperplasia while KO mice showed mitigated such responses compared to PM-induced allergic asthma WT mice. These results prove that IL-17A plays a key role in pathogenesis of PM-induced allergic asthma. This research was funded by the Ministry of Education. This research was funded by the Ministry of Education