Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Ministry of Education, Shanghai Ocean University, Shanghai, China; International Research Center for Marine Biosciences, Ministry of Science and Technology, Shanghai Ocean University, Shanghai, China.
Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Ministry of Education, Shanghai Ocean University, Shanghai, China; International Research Center for Marine Biosciences, Ministry of Science and Technology, Shanghai Ocean University, Shanghai, China.
Fish Shellfish Immunol. 2023 Dec;143:109225. doi: 10.1016/j.fsi.2023.109225. Epub 2023 Nov 16.
Liver-expressed antimicrobial peptide 2 (LEAP2) is a blood-derived antimicrobial peptide expressed predominantly in the liver. Although LEAP2 has been reported to exert antimicrobial effects in various fish species, its antimicrobial mechanism is not entirely understood. Zebrafish is an intensively developing animal model for studying bacterial diseases. In this study, we used zebrafish to identify the role of LEAP2 in bacterial infection. We found that knockout of LEAP2 in zebrafish led to a higher bacterial burden and mortality. To further investigate the effect of LEAP2 mutation on the immune system, we conducted a comparative transcriptome analysis of zebrafish with a mutant of LEAP2. Based on gene ontologies (GO) enrichment, LEAP2 mutant zebrafish revealed that, compared to wild-type zebrafish, robust responses to bacteria, inflammatory factors, and disrupt immune homeostasis and induct hyperinflammation. Furthermore, based on Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis, six immune pathways were identified: Phagosome, NOD-like receptor, ferroptosis, Cytokine-cytokine receptor, Toll-like receptor, and FOXO signalling pathways. Interestingly, besides the liver, muscle, intestine, and eggs are also significantly enriched to the ferroptosis pathway, as revealed using quantitative polymerase chain reaction (qPCR), further confirmed that the effect of LEAP2 mutations on inflammatory factors and ferroptosis-related genes. Most importantly, this is the first report of the zebrafish LEAP2 mutant transcriptome obtained using high-throughput sequencing. Our study employed comparative transcriptome analysis to reveal the inflammatory response and ferroptosis-signalling pathway as a novel potential mechanism of LEAP2 antibacterial activity, laying the foundation for future studies of LEAP2 immune functions.
肝表达抗菌肽 2（LEAP2）是一种主要在肝脏中表达的血液来源的抗菌肽。虽然已经报道 LEAP2 在各种鱼类中具有抗菌作用，但它的抗菌机制尚不完全清楚。斑马鱼是研究细菌性疾病的一种重要的动物模型。在本研究中，我们使用斑马鱼来鉴定 LEAP2 在细菌感染中的作用。我们发现，斑马鱼中 LEAP2 的敲除导致细菌负荷和死亡率增加。为了进一步研究 LEAP2 突变对免疫系统的影响，我们对 LEAP2 突变的斑马鱼进行了比较转录组分析。基于基因本体论（GO）富集分析，与野生型斑马鱼相比，LEAP2 突变斑马鱼对细菌、炎症因子和破坏免疫平衡以及诱导过度炎症有强烈的反应。此外，基于京都基因与基因组百科全书（KEGG）分析，确定了 6 条免疫途径：吞噬体、NOD 样受体、铁死亡、细胞因子-细胞因子受体、Toll 样受体和 FOXO 信号通路。有趣的是，除了肝脏，肌肉、肠道和卵子也显著富集到铁死亡途径，这是通过定量聚合酶链反应（qPCR）进一步证实的，这进一步证实了 LEAP2 突变对炎症因子和铁死亡相关基因的影响。最重要的是，这是首次利用高通量测序获得斑马鱼 LEAP2 突变转录组的报告。我们的研究采用比较转录组分析揭示了炎症反应和铁死亡信号通路作为 LEAP2 抗菌活性的一种新的潜在机制，为未来研究 LEAP2 的免疫功能奠定了基础。
