The innate antiviral response upregulates IL-13 receptor α2 in bronchial fibroblasts

Background: IL-13 is key mediator of allergic inflammation in asthmatic patients. We have previously shown that the decoy receptor IL-13 receptor (IL-13R) alpha 2 attenuates responses of fibroblasts to IL-13. Because the expression of IL-13R alpha 2 can be regulated by IFN-gamma, a type II interferon, we hypothesized that innate antiviral responses characterized by type I interferon expression can also induce IL-13R alpha 2 expression. Objective: We sought to induce an innate antiviral response in primary fibroblasts using exposure to double-stranded RNA (dsRNA) and to examine the expression and function of IL-13R alpha 2. Methods: Primary human fibroblasts were cultured from endobronchial biopsy specimens obtained from healthy or asthmatic volunteers and challenged with dsRNA. Upregulation of IL-13R alpha 2 mRNA was measured by using real-time quantitative PCR, and cell-surface IL-13R alpha 2 protein expression was measured by using fluorescence-activated cell sorting. Eotaxin release was determined by means of ELISA. Results: Direct treatment with IFN-beta led to an upregulation of IL-13R alpha 2. Exposure to dsRNA rapidly induced IFN-beta mRNA in fibroblasts, and this was followed by significant induction of IL-13R alpha 2 mRNA and cell-surface protein expression, which was dependent on de novo protein synthesis. A neutralizing antibody to the IFN-alpha/beta receptor blocked cell-surface expression of IL-13R alpha 2 in the presence of dsRNA. Pretreatment of fibroblasts with dsRNA led to attenuation of IL-13-stimulated eotaxin production. However, the presence of an IL13R alpha 2 neutralizing antibody restored IL-13-stimulated eotaxin production in dsRNA-treated cells. Conclusion: IFN-beta induces IL-13R alpha 2 expression, leading to a consequential suppression of responsiveness to IL-13. These data suggest cross-talk between T(H)1 and T(H)2 pathways and point to an immunomodulatory role for IL-13R alpha 2 in human bronchial fibroblasts during viral infection. (J Allergy Clin Immunol 2013; 131:849-55.)