Interferon-γ Stimulates Interleukin-27 Derived from Dendritic Cells to Regulate Th9 Differentiation through STAT1/3 Pathway

The initiation and progression of allergic asthma (AA) are associated with complex interactions between inflammation and immune response. Herein, we report the specific mechanisms underlying the molecular action of interferon (IFN)-γ in AA regulation. We speculated that IFN-γ inhibits Th9 differentiation by regulating the secretion of interleukin (IL)-27 from dendritic cells (DCs), thereby suppressing airway inflammation in asthma. We constructed a mouse model of ovalbumin-induced AA and overexpressed IFN-γ to evaluate the effect on the IL-27/Th9 axis via the in vitro effect of IFN-γ on IL-27 secretion by DCs and their influence on Th9 differentiation and asthmatic inflammation. IFN-γ overexpression reduced the proportion of Th9 cells and DCs and altered lung morphology and cytokine production in AA-induced mice, thus suppressing the AA phenotype. In addition, exogenous IFN-γ stimulation promoted the secretion of IL-27 and suppressed Th9 differentiation of CD4+ T cells via signal transducer and activator of transcription 1/3 (STAT1/3) signaling in a time-dependent manner. This study aimed to clarify the regulatory effect and mechanism of the IFN-γ/DCs/IL-27/Th9 axis on AA and provide novel insights for effective targeted treatment of asthma.