Immunomodulation in allergic rhinitis: Insights from Th2 cells and NLRP3/IL-18 pathway

Allergic rhinitis (AR) is characterized by nasal symptoms such as rubbing and sneezing, often triggered by allergen exposure. The purpose of this study is to dissect the roles of NLRP3-mediated immune modulation and macrophage pyroptosis in modulating T cell differentiation within the context of ovalbumin (OVA)-induced AR in mice. OVA-induced AR was established in mice, evaluating nasal symptoms, macrophage infiltration, cytokine levels, and T cell differentiation. Manipulations using NLRP3-/-, ASC-/- mice, clodronate liposome treatment, and NLRP3 inhibitor MCC950 were performed to assess their impact on AR symptoms and immune responses. Following OVA stimulation, increased nasal symptoms were observed in the OVA group along with augmented GATA3 expression and elevated IL-4 and IL-1b levels, indicative of Th2 polarization and cellular pyroptosis involvement. NLRP3-/- and ASC-/- mice exhibited reduced CD3+ T cells post OVA induction, implicating cellular pyroptosis in AR. Macrophage depletion led to decreased IgE levels, highlighting their involvement in allergic responses. Further investigations revealed enhanced macrophage pyroptosis, influencing Th1/Th2 differentiation in AR models. IL-18 released through NLRP3-mediated pyroptosis induced Th2 differentiation, distinct from IL-1b. Additionally, MCC950 effectively mitigated AR symptoms by modulating Th2 responses and reducing macrophage infiltration. This comprehensive study unravels the pivotal role of NLRP3-mediated immune modulation and macrophage pyroptosis in Th1/Th2 balance regulation in OVA-induced AR. Targeting NLRP3 pathways with MCC950 emerged as a promising strategy to alleviate AR symptoms, providing insights for potential therapeutic interventions in AR management.