Xia Junliang, Chen Weiding, Xu Chengxun, Wang Meihuizi, Mo Guodong, Zhang Xiquan
Department of Animal Genetics, Breeding and Reproduction, College of Animal Science, South China Agricultural University, Guangzhou, Guangdong, China; Guangdong Provincial Key Laboratory of Agro-Animal Genomics and Molecular Breeding, and Key Lab of Chicken Genetics, Breeding and Reproduction, Ministry of Agriculture and Rural Affair, Guangzhou, Guangdong, China; State Key Laboratory of Swine and Poultry Breeding Industry, Guangzhou, China.
Guangxi Vocational University of Agriculture, Nanning, 530007 Guangxi, China.
Poult Sci. 2025 Aug 6;104(11):105648. doi: 10.1016/j.psj.2025.105648.
Avian leukosis viruses (ALVs) are a group of retroviruses with immunosuppressive and tumorigenic effects, causing substantial economic losses to the poultry industry due to the lack of effective commercial vaccines and antiviral drugs. Granulocyte colony-stimulating factor 3 (CSF3) is a cytokine that regulates hematopoiesis and modulates the proliferation and differentiation of immune cells. In our previous study, we unexpectedly observed that CSF3 expression was significantly upregulated upon stimulation with interferon-α (IFN-α) and ALV, suggesting a potential role in ALV infection. In this study, we confirmed that the CSF3 promoter could be activated by ALV and polyinosinic-polycytidylic acid (poly I:C) using a CSF3 promoter-driven reporter construct, and GAS potentially serving as the response element. Phylogenetic analysis showed that avian and mammalian CSF3 genes clustered separately within the phylogenetic tree. Subsequently, we overexpressed and silenced CSF3 in DF-1 cells followed by ALV-J infection. Transcriptome analysis revealed that CSF3 overexpression significantly upregulated genes involved in antiviral and inflammatory responses, particularly those in the TLR, RIG-I, JAK/STAT, and NF-κB signaling pathways. Our results demonstrated that CSF3 induced the expression of IFNs and antiviral genes (IRF7, Mx, MDA5, OASL, and ACSL1). Furthermore, CSF3 improved the phosphorylation level of IκBα, leading to the production of pro-inflammatory cytokines and activation of the NF-κB pathway, ultimately suppressing ALV-J envelope glycoprotein expression. Notably, the pro-inflammatory and antiviral effects of CSF3 were abolished upon treatment with a STAT3 inhibitor, suggesting that CSF3 exerts its antiviral function through STAT3 phosphorylation. A similar effect of CSF3 was observed in primary fibroblasts derived from chicken embryos. Collectively, our findings indicate that CSF3 may function as an atypical interferon-stimulated gene (ISG), enhancing the immune response against ALV-J by activating the NF-κB signaling pathway and interferon-mediated antiviral mechanisms. These results not only reveal the antiviral role of CSF3 but also provide new insights into the host's innate immune response to ALV. Furthermore, they highlight the potential of CSF3 as a candidate resistance gene for breeding programs or as a vaccine adjuvant for disease prevention.
禽白血病病毒（ALVs）是一类具有免疫抑制和致瘤作用的逆转录病毒，由于缺乏有效的商业疫苗和抗病毒药物，给家禽业造成了巨大的经济损失。粒细胞集落刺激因子3（CSF3）是一种调节造血并调控免疫细胞增殖和分化的细胞因子。在我们之前的研究中，我们意外地观察到，在用干扰素-α（IFN-α）和ALV刺激后，CSF3的表达显著上调，这表明其在ALV感染中可能发挥作用。在本研究中，我们使用CSF3启动子驱动的报告基因构建体证实，CSF3启动子可被ALV和聚肌苷酸-聚胞苷酸（poly I:C）激活，并且GAS可能作为应答元件。系统发育分析表明，禽类和哺乳动物的CSF3基因在系统发育树中分别聚类。随后，我们在DF-1细胞中过表达和沉默CSF3，然后进行ALV-J感染。转录组分析显示，CSF-3过表达显著上调了参与抗病毒和炎症反应的基因，特别是那些在TLR、RIG-I、JAK/STAT和NF-κB信号通路中的基因。我们的结果表明，CSF3诱导了IFN和抗病毒基因（IRF7、Mx、MDA5、OASL和ACSL1）的表达。此外，CSF3提高了IκBα的磷酸化水平，导致促炎细胞因子的产生和NF-κB通路的激活，最终抑制了ALV-J包膜糖蛋白的表达。值得注意的是，在用STAT3抑制剂处理后，CSF3的促炎和抗病毒作用被消除，这表明CSF3通过STAT3磷酸化发挥其抗病毒功能。在源自鸡胚的原代成纤维细胞中也观察到了CSF3的类似作用。总的来说，我们的研究结果表明，CSF3可能作为一种非典型的干扰素刺激基因（ISG），通过激活NF-κB信号通路和干扰素介导的抗病毒机制来增强对ALV-J的免疫反应。这些结果不仅揭示了CSF3的抗病毒作用，还为宿主对ALV的固有免疫反应提供了新的见解。此外，它们突出了CSF3作为育种计划的候选抗性基因或作为疾病预防的疫苗佐剂的潜力。
