Gao Jin-Hua, Zhao Jin-Liang, Guo Ning-Xin, Tola Temesgen, Xue Wen-Bo, Cai Kang-Ning, Yao Xiao-Li, Hu Miao
Key Laboratory of Freshwater Aquatic Genetic Resources, Ministry of Agriculture and Rural Affairs, Shanghai Ocean University, Shanghai, 201306, PR China; Shanghai Engineering Research Center of Aquaculture, Shanghai Ocean University, Shanghai, 201306, PR China; National Demonstration Center for Experimental Fisheries Science Education, Shanghai Ocean University, Shanghai, 201306, PR China.
Key Laboratory of Freshwater Aquatic Genetic Resources, Ministry of Agriculture and Rural Affairs, Shanghai Ocean University, Shanghai, 201306, PR China; Shanghai Engineering Research Center of Aquaculture, Shanghai Ocean University, Shanghai, 201306, PR China; National Demonstration Center for Experimental Fisheries Science Education, Shanghai Ocean University, Shanghai, 201306, PR China.
Fish Shellfish Immunol. 2024 Dec;155:110003. doi: 10.1016/j.fsi.2024.110003. Epub 2024 Nov 2.
Bacterial septicemia caused by Aeromonas hydrophila is one of the common bacterial diseases in aquaculture. Antimicrobial peptides, including hepcidin, are key components of the innate immune system in fish, playing a role in defense against pathogens. This study investigated the defense patterns of hepcidin in mandarin fish (Siniperca chuatsi) following A. hydrophila infection using gene expression analysis and in vitro antibacterial assays. We measured changes in the expression of iron metabolism-related genes (hepcidin, fpn, ftn, tf, tfr1) and immune-related genes (il-1β, il-6, il-8, il-10, tnf-α, socs3, nkap, tlr1, tlr2) in the intestine post-infection. MBC experiment demonstrated that the hepcidin synthetic peptide has an inhibitory effect on the growth of V. parahaemolyticus (32 μg/ml), A. hydrophilus (64 μg/ml), and F. columnaris (128 μg/ml), but not E. tarda (>256 μg/ml). After A. hydrophilus challenge, fpn, tf and tfr1 with peak expression at 24 hpi (2.75), 12 hpi (4.43) and 6 hpi (7.41), respectively. Hepcidin and ftn expression was highest at 48 hpi (115.01) and 72 hpi (4.16). The Fe content peaked at 6 hpi (2.64 μmol/l) and reached its lowest at 12 hpi (1.12 μmol/l) in the intestine. After pathogen challenge, il-1β, il-8, socs3, tlr2, and hepcidin showed trends of increased and then decreased, with peak expression at 72 hpi (5.13, 37.05, 3.08) and 48 hpi (5.35, 115.01), respectively. These findings suggested that hepcidin plays a key role in the defense against A. hydrophila: initially restricting bacterial growth through iron metabolism (0-48 hpi), and later modulating immune responses via the TNF (by inducing il-1β and socs3) and Toll-like receptor pathways (by inducing il-8 and tlr2) (48-96 hpi). This study provides novel insights into the immune function of hepcidin in fish and its potential application in managing bacterial infections in aquaculture.
嗜水气单胞菌引起的细菌性败血症是水产养殖中常见的细菌性疾病之一。抗菌肽，包括铁调素，是鱼类先天免疫系统的关键组成部分，在抵御病原体方面发挥作用。本研究通过基因表达分析和体外抗菌试验，研究了鳜鱼（Siniperca chuatsi）在感染嗜水气单胞菌后铁调素的防御模式。我们测量了感染后肠道中铁代谢相关基因（铁调素、铁转运蛋白1、铁蛋白、转铁蛋白、转铁蛋白受体1）和免疫相关基因（白细胞介素-1β、白细胞介素-6、白细胞介素-8、白细胞介素-10、肿瘤坏死因子-α、细胞因子信号转导抑制因子3、核因子κB激活蛋白、Toll样受体1、Toll样受体2）表达的变化。MBC实验表明，铁调素合成肽对副溶血性弧菌（32μg/ml）、嗜水气单胞菌（64μg/ml）和柱状黄杆菌（128μg/ml）的生长有抑制作用，但对迟钝爱德华氏菌（>256μg/ml）无抑制作用。嗜水气单胞菌攻毒后，铁转运蛋白1、转铁蛋白和转铁蛋白受体1分别在感染后24小时（2.75）、12小时（4.43）和6小时（7.41）达到表达峰值。铁调素和铁蛋白的表达在感染后48小时（115.01）和72小时（4.16）最高。肠道中铁含量在感染后6小时达到峰值（2.64μmol/l），在12小时达到最低值（1.12μmol/l）。病原体攻毒后，白细胞介素-1β、白细胞介素-8、细胞因子信号转导抑制因子3、Toll样受体2和铁调素呈现先升高后降低的趋势，分别在感染后72小时（5.13、37.05、3.08）和48小时（5.35、115.01）达到表达峰值。这些发现表明，铁调素在抵御嗜水气单胞菌方面发挥关键作用：最初通过铁代谢限制细菌生长（0-48小时），随后通过肿瘤坏死因子（诱导白细胞介素-1β和细胞因子信号转导抑制因子3）和Toll样受体途径（诱导白细胞介素-8和Toll样受体2）调节免疫反应（48-96小时）。本研究为铁调素在鱼类中的免疫功能及其在水产养殖细菌感染管理中的潜在应用提供了新的见解。
