Sporothrix schenckii regulates macrophage inflammatory responses via the c-JUN-induced Dab2 transcription.

Macrophages, which serve as a bridge between innate and adaptive immunity, play an important role in sporotrichosis. Sporothrix schenckii infections can produce immune responses such as macrophage polarization and inflammatory factor secretion. In the early stages of inflammation, the expression of DAB2 in macrophages is increased, which controls the secretion of inflammatory factors and affects the polarization of macrophages. However, the expressions and mechanisms of DAB2 in sporotrichosis are not clear. In this study, we examined the expression of DAB2 and its regulation of inflammatory factors under conditions of Sporothrix schenckii infection. Our results indicated that the Sporothrix schenckii infection increased the expression of DAB2 and revealed a mixed M1/M2-like type of gene expression in BMDMs with the inhibited Il-6, Il1-β and Arg-1 and induced Tnf-α, Il-10 and Mgl-1. The deficiency of Dab2 gene suspended the changes of cytokines. In addition, JNK activity in BMDMs was inhibited by Sporothrix schenckii infection, leading to an increase in c-JUN. We also identified c-JUN as a transcription factor for Dab2 through chromatin immunoprecipitation and luciferase reporter assays. In an in vivo mouse model, sporotrichosis-induced skin lesions were accompanied with an upregulation of c-JUN and inhibition of JNK activity, which were in accord with findings from in vitro experiments. Taken together, these findings indicate that in the early stages of Sporothrix schenckii infection there is a promotion of DAB2 expression through the JNK/c-JUN pathway, effects that can then control the expression of inflammatory factors.