Downregulation of common cytokine receptor γ chain inhibits inflammatory responses in macrophages stimulated with Riemerella anatipestifer

Abstract

Th17-cell-mediated inflammation is affected by the soluble form of common cytokine receptor γ chain (γ_c). We previously suggested that inflammatory cytokines including interleukin (IL)-17A are associated with Riemerella anatipestifer infection, which a harmful bacterial pathogen in ducks. Here, the expression profiles of membrane-associated γ_c (duγ_c-a) and soluble γ_c (duγ_c-b) in R. anatipestifer-stimulated splenic lymphocytes and macrophages, and in the spleens and livers of R. anatipestifer-infected ducks, were investigated. In vitro and in vivo results indicated that the expression levels of both forms of γ_c were increased, showing that marked increases were detected in the expression of the duγ_c-b form rather than the duγ_c-a form. Treatment with γ_c-specific siRNA downregulated mRNA expression of Th17-related cytokines, including IL-17A and IL-17F, in duck splenic macrophages stimulated with R. anatipestifer, whereas the expressions of interferon (IFN)-γ and IL-2 were enhanced. The results showed that the upregulation of γ_c, especially the duγ_c-b form, was associated with expression of Th17-related cytokines during R. anatipestifer infection.

Keywords: Common cytokine receptor γ chain; Ducks; Inflammatory cytokines; Riemerella anatipestifer infection; Small interfering RNAs.