Identification, expression pattern and functional characterization of IFN-γ involved in activating JAK-STAT pathway in Sebastes schlegeli

• Published in: Fish & shellfish immunology Vol. 140; p. 108936
• Main Authors: Zhang, Min, Liu, Wen-qing, Wang, Yue, Yan, Xue, Wang, Bing, Wang, Guang-hua
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.09.2023
• Subjects: Immunoregulation; Recombinant protein; Sebastes schlegeli; SsIFN-γ; Recombinant protein; Immunoregulation; Sebastes schlegeli; SsIFN-γ
• ISSN: 1050-4648; 1095-9947
• DOI: 10.1016/j.fsi.2023.108936

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. •A novel IFN-γ from black rockfish, Sebastes schlegeli (named SsIFN-γ) was characterized.•The relative expression of SsIFN-γ was significantly upregulated in immune-related tissues (spleen and head kidney) after treatment in vivo with Vibrio anguillarum, Edwardsiella tarda or polyI:C.•The recombinant protein (rSsIFN-γ) exhibited an immunomodulatory function to enhance respiratory burst activity and nitric oxide response of HK macrophages.•rSsIFN-γ could effectively upregulate the expression of macrophage proinflammatory cytokine (TNFα, IL-1β, IL-6, IL-8), the expression of JAK-STAT signaling pathway related genes (STAT1, SOCS1) and downstream antiviral genes (Viperin, IFP35 and ISG15).