Department of Biological Sciences, University of Alberta, Edmonton, Alberta T6E 2E9, Canada.
J Biol Chem. 2010 Jul 30;285(31):23537-47. doi: 10.1074/jbc.M109.096925. Epub 2010 May 27.
Unlike mammals, bony fish have two type II interferons, IFNgamma and IFNgammarel, whose pro-inflammatory functions have not been fully characterized. To elucidate the distinct roles of these type II interferons of bony fish, we examined the effects of recombinant goldfish (rg) IFNgamma and IFNgammarel on the macrophage antimicrobial responses, immune gene expression, and their signaling pathways. Our findings indicate that rgIFNgamma and rgIFNgammarel possess unique capacities to mediate each of the above processes. Q-PCR analysis revealed similar expression of both cytokines in tissues and immune cell populations of the goldfish, although IFNgamma mRNA levels were generally higher in most tissues and cell types. Whereas rgIFNgamma had long-lasting effects on the priming of goldfish monocyte ROI production, the rgIFNgammarel had relatively short-lived ROI priming potential and eventually down-regulated the priming of ROI production induced by rgIFNgamma or rgTNFalpha2. Whereas rgIFNgamma induced relatively modest phagocytic and nitric oxide responses of goldfish macrophages, rgIFNgammarel induced significantly higher phagocytosis, iNOSA and iNOSB gene expression and nitric oxide production compared with rgIFNgamma. The rgIFNgamma and rgIFNgammarel induced different gene expression profiles in goldfish monocytes. These differences included significantly higher induction of TNFalpha2, CXCL8, ceruloplasmin, and interferon regulatory factor (IRFs) expression after activation of monocytes with rgIFNgammarel. The rgIFNgammarel was more abundant in whole cell lysates compared with rgIFNgamma. Both cytokines induced the phosphorylation of Stat1, while the nuclear localization of Stat1 was only observed following treatment of monocytes with rgIFNgamma. Our findings suggest the presence of functional segregation of the induction of macrophage antimicrobial functions by type II interferons of bony fish.
与哺乳动物不同，硬骨鱼有两种 II 型干扰素，IFNγ和 IFNgammarel，它们的促炎功能尚未完全阐明。为了阐明硬骨鱼这两种 II 型干扰素的不同作用，我们研究了重组金鱼（rg）IFNγ和 IFNgammarel 对巨噬细胞抗菌反应、免疫基因表达及其信号通路的影响。我们的研究结果表明，rgIFNγ和 rgIFNgammarel 具有独特的能力来介导上述过程中的每一个过程。Q-PCR 分析显示，这两种细胞因子在金鱼的组织和免疫细胞群体中均有相似的表达，尽管 IFNγ mRNA 水平在大多数组织和细胞类型中普遍较高。虽然 rgIFNγ对金鱼单核细胞 ROI 产生的启动具有持久的影响，但 rgIFNgammarel 的 ROI 启动潜力相对较短，最终下调了 rgIFNγ或 rgTNFalpha2 诱导的 ROI 产生的启动。虽然 rgIFNγ诱导金鱼巨噬细胞产生适度的吞噬和一氧化氮反应，但 rgIFNgammarel 诱导的吞噬、iNOSA 和 iNOSB 基因表达和一氧化氮产生显著高于 rgIFNγ。rgIFNγ和 rgIFNgammarel 在金鱼单核细胞中诱导不同的基因表达谱。这些差异包括 rgIFNgammarel 激活单核细胞后 TNFalpha2、CXCL8、铜蓝蛋白和干扰素调节因子（IRFs）的表达显著增加。与 rgIFNγ相比，rgIFNgammarel 在整个细胞裂解物中更为丰富。两种细胞因子均诱导 Stat1 的磷酸化，而只有在用 rgIFNγ处理单核细胞后才观察到 Stat1 的核定位。我们的研究结果表明，硬骨鱼 II 型干扰素诱导巨噬细胞抗菌功能的诱导存在功能分离。
