Academic Unit of Clinical and Experimental Sciences and the Southampton NIHR Respiratory Biomedical Research Unit, University of Southampton Faculty of Medicine, Sir Henry Wellcome Laboratories, Southampton General Hospital, Southampton, United Kingdom.
J Allergy Clin Immunol. 2013 Mar;131(3):849-55. doi: 10.1016/j.jaci.2012.08.030. Epub 2012 Oct 12.
IL-13 is key mediator of allergic inflammation in asthmatic patients. We have previously shown that the decoy receptor IL-13 receptor (IL-13R) α2 attenuates responses of fibroblasts to IL-13. Because the expression of IL-13Rα2 can be regulated by IFN-γ, a type II interferon, we hypothesized that innate antiviral responses characterized by type I interferon expression can also induce IL-13Rα2 expression.
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-13Rα2.
Primary human fibroblasts were cultured from endobronchial biopsy specimens obtained from healthy or asthmatic volunteers and challenged with dsRNA. Upregulation of IL-13Rα2 mRNA was measured by using real-time quantitative PCR, and cell-surface IL-13Rα2 protein expression was measured by using fluorescence-activated cell sorting. Eotaxin release was determined by means of ELISA.
Direct treatment with IFN-β led to an upregulation of IL-13Rα2. Exposure to dsRNA rapidly induced IFN-β mRNA in fibroblasts, and this was followed by significant induction of IL-13Rα2 mRNA and cell-surface protein expression, which was dependent on de novo protein synthesis. A neutralizing antibody to the IFN-α/β receptor blocked cell-surface expression of IL-13Rα2 in the presence of dsRNA. Pretreatment of fibroblasts with dsRNA led to attenuation of IL-13-stimulated eotaxin production. However, the presence of an IL-13Rα2 neutralizing antibody restored IL-13-stimulated eotaxin production in dsRNA-treated cells.
IFN-β induces IL-13Rα2 expression, leading to a consequential suppression of responsiveness to IL-13. These data suggest cross-talk between TH1 and TH2 pathways and point to an immunomodulatory role for IL-13Rα2 in human bronchial fibroblasts during viral infection.
IL-13 是哮喘患者过敏炎症的关键介质。我们之前已经表明，诱饵受体 IL-13 受体 (IL-13R)α2 可减弱成纤维细胞对 IL-13 的反应。由于 IL-13Rα2 的表达可以被 IFN-γ（一种 II 型干扰素）调节，我们假设以 I 型干扰素表达为特征的先天抗病毒反应也可以诱导 IL-13Rα2 的表达。
我们试图使用双链 RNA（dsRNA）在原代成纤维细胞中诱导先天抗病毒反应，并研究 IL-13Rα2 的表达和功能。
从健康或哮喘志愿者的支气管活检标本中培养原代人成纤维细胞，并使用 dsRNA 进行挑战。通过实时定量 PCR 测量 IL-13Rα2 mRNA 的上调，通过荧光激活细胞分选测量细胞表面 IL-13Rα2 蛋白表达。通过 ELISA 测定嗜酸性粒细胞趋化因子释放。
IFN-β 的直接治疗导致 IL-13Rα2 的上调。dsRNA 快速诱导成纤维细胞中的 IFN-β mRNA，随后显著诱导 IL-13Rα2 mRNA 和细胞表面蛋白表达，这依赖于从头蛋白质合成。dsRNA 存在时，针对 IFN-α/β 受体的中和抗体阻断 IL-13Rα2 的细胞表面表达。dsRNA 预处理可减弱 IL-13 刺激的嗜酸性粒细胞趋化因子产生。然而，在 dsRNA 处理的细胞中存在 IL-13Rα2 中和抗体恢复了 IL-13 刺激的嗜酸性粒细胞趋化因子产生。
IFN-β 诱导 IL-13Rα2 的表达，导致对 IL-13 的反应性降低。这些数据表明 TH1 和 TH2 途径之间存在串扰，并指出在病毒感染期间 IL-13Rα2 在人支气管成纤维细胞中具有免疫调节作用。
