State Key Laboratory for Biocontrol, Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), School of Marine Sciences, Sun Yat-sen University, No.132 Waihuan Dong Road, Higher Education Mega Center, Guangzhou, Guangdong, 510006, PR China; Institute of Aquatic Economic Animals, Guangdong Province Key Laboratory for Aquatic Economic Animals, School of Life Sciences, Sun Yat-sen University, 135 Xingang Road West, Guangzhou, 510275, PR China.
State Key Laboratory for Biocontrol, Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), School of Marine Sciences, Sun Yat-sen University, No.132 Waihuan Dong Road, Higher Education Mega Center, Guangzhou, Guangdong, 510006, PR China.
Fish Shellfish Immunol. 2020 May;100:80-89. doi: 10.1016/j.fsi.2020.02.062. Epub 2020 Mar 2.
The mandarin fish Siniperca chuatsi is a cultured freshwater fish species that is popular in China because of its high market value. With the development of high-density cultural mode in mandarin fish, viral diseases such as Infectious spleen and kidney necrosis virus (ISKNV) are becoming increasingly serious. Stimulator of interferon genes (STING) is a central component in the innate immune response to cytosolic DNA and RNA derived from different pathogens. However, the roles of STING in innate immune response of mandarin fish remain unknown. In the present study, S. chuatsi STING (scSTING)-mediated host immune response against ISKNV infection was investigated. ScSTING transcription level increased remarkably in response to ISKNV infection, LPS, PMA, or poly (I:C) stimulation in mandarin fish fry (MFF-1) cells. Immunofluorescence results showed that scSTING localized majorly in the endoplasmic reticulum. scSTING overexpression remarkably increased the expression levels of scIFN-h, scMx, scISG15, scPKR, scViperin, scIL-1β, scIL-18, and scTNF-α genes. IFN-β-luciferase report assay results showed that the relative expressions of luciferin were remarkably increased in MFF-1 cells. Site mutation of serine (S) on C-terminus of scSTING showed that both S388 and S396 were important for mediated signaling. Furthermore, scSTING overexpression inhibited ISKNV infection, and knockdown of scSTING promoted ISKNV infection, indicating that scSTING could suppress ISKNV infection in MFF-1 cells. These observations suggested that the scSTING played an important role in innate immune against ISKNV infection. Our work would help elucidate the roles of teleost fish STING in innate immunity.
翘嘴红鲌（Siniperca chuatsi）是一种养殖淡水鱼类，因其市场价值高而在中国广受欢迎。随着翘嘴红鲌高密度养殖模式的发展，传染性脾肾坏死病毒（ISKNV）等病毒性疾病日益严重。干扰素基因刺激蛋白（STING）是对来自不同病原体的细胞质 DNA 和 RNA 的先天免疫反应的核心组成部分。然而，STING 在翘嘴红鲌先天免疫反应中的作用尚不清楚。在本研究中，研究了 S. chuatsi STING（scSTING）介导的对 ISKNV 感染的先天免疫反应。scSTING 的转录水平在翘嘴红鲌鱼苗（MFF-1）细胞中对 ISKNV 感染、LPS、PMA 或 poly（I:C）刺激显著增加。免疫荧光结果表明，scSTING 主要定位于内质网。scSTING 的过表达显著增加了 scIFN-h、scMx、scISG15、scPKR、scViperin、scIL-1β、scIL-18 和 scTNF-α 基因的表达水平。IFN-β-荧光素酶报告基因检测结果表明，MFF-1 细胞中荧光素的相对表达显著增加。scSTING 羧基末端丝氨酸（S）的位点突变表明 S388 和 S396 对介导信号都很重要。此外，scSTING 的过表达抑制了 ISKNV 的感染，而 scSTING 的敲低促进了 ISKNV 的感染，表明 scSTING 可以抑制 MFF-1 细胞中的 ISKNV 感染。这些观察结果表明，scSTING 在先天免疫抵抗 ISKNV 感染中发挥重要作用。我们的工作将有助于阐明硬骨鱼类 STING 在先天免疫中的作用。
