School of Marine Science and Engineering, Qingdao Agricultural University, Qingdao, Shandong Province, 266109, China; Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology, Qingdao, Shandong Province, 266109, China.
School of Marine Science and Engineering, Qingdao Agricultural University, Qingdao, Shandong Province, 266109, China.
Fish Shellfish Immunol. 2023 Sep;140:108936. doi: 10.1016/j.fsi.2023.108936. Epub 2023 Jul 7.
IFN-γ (interferon gamma) is a critical cytokine in the immune system involved both directly and indirectly in antiviral activity, stimulation of bactericidal activity, antigen presentation and activation of macrophages via the Janus kinase/signal transducer and activator of transcription (JAK-STAT) pathway. The IFN-γ function is best described in cell defense against intracellular pathogens in mammals, but IFN-γ cytokine-induced metabolic change and its role in anti-infection remain unknown in teleost fish. In this study, a novel IFN-γ (SsIFN-γ) was identified from black rockfish (Sebastes schlegeli) by rapid amplification of cDNA ends (RACE). The open reading frame (ORF) of SsIFN-γ encoded a putative protein of 215 amino acids and shares 60.2%-93.5% overall sequence identities with other teleost IFN-γ. SsIFN-γ was distributed ubiquitously in all the detected tissues and immune cells, which was highly expressed in the spleen, gills, head kidney by quantitative real-time PCR. The mRNA expression of SsIFN-γ was significantly upregulated in the spleen, head kidney, head kidney (HK) macrophages and peripheral blood lymphocytes (PBLs) during pathogen infection. Meanwhile, the recombinant protein (rSsIFN-γ) exhibited an immunomodulatory function to enhance respiratory burst activity and nitric oxide response of HK macrophages. Furthermore, rSsIFN-γ could effectively upregulate the expression of macrophage proinflammatory cytokine, the expression of JAK-STAT signaling pathway related genes and interferon-related downstream genes in the head kidney and spleen. Luciferase assays showed ISRE and GAS activity were obviously enhanced after rSsIFN-γ treatment. These results indicated that SsIFN-γ possessed apparent immunoregulatory properties and played a role in fighting pathogen infection which will be helpful to further understanding of the immunologic mechanism of teleosts IFN-γ in innate immunity.
干扰素-γ（IFN-γ）是免疫系统中的一种关键细胞因子，它直接或间接地参与抗病毒活性、刺激杀菌活性、抗原呈递以及通过 Janus 激酶/信号转导和转录激活因子（JAK-STAT）途径激活巨噬细胞。IFN-γ 的功能在哺乳动物细胞防御细胞内病原体方面表现得最为明显，但 IFN-γ 细胞因子诱导的代谢变化及其在抗感染中的作用在硬骨鱼类中仍然未知。在这项研究中，通过快速扩增 cDNA 末端（RACE），从黑鲷（Sebastes schlegeli）中鉴定出一种新型 IFN-γ（SsIFN-γ）。SsIFN-γ 的开放阅读框（ORF）编码一个推测的 215 个氨基酸的蛋白质，与其他硬骨鱼 IFN-γ 的整体序列同一性为 60.2%-93.5%。SsIFN-γ 在所有检测到的组织和免疫细胞中广泛分布，在脾脏、鳃和头肾中通过定量实时 PCR 高度表达。在病原体感染期间，SsIFN-γ 在脾脏、头肾、头肾（HK）巨噬细胞和外周血淋巴细胞（PBLs）中的 mRNA 表达显著上调。同时，重组蛋白（rSsIFN-γ）表现出免疫调节功能，可增强 HK 巨噬细胞的呼吸爆发活性和一氧化氮反应。此外，rSsIFN-γ 可有效上调头肾和脾脏中巨噬细胞促炎细胞因子的表达、JAK-STAT 信号通路相关基因的表达以及干扰素相关下游基因的表达。荧光素酶测定表明，rSsIFN-γ 处理后 ISRE 和 GAS 活性明显增强。这些结果表明，SsIFN-γ 具有明显的免疫调节特性，在抵抗病原体感染中发挥作用，这将有助于进一步了解硬骨鱼 IFN-γ 在先天免疫中的免疫机制。
