Department of Veterinary Medicine, College of Veterinary Medicine, National Pingtung University of Science and Technology, Pingtung, Taiwan; International Degree Program of Ornamental Fish Technology and Aquatic Animal Health, International College, National Pingtung University of Science and Technology, Pingtung, Taiwan; General Research Service Centre, National Pingtung University of Science and Technology, Pingtung, Taiwan.
Department of Veterinary Medicine, College of Veterinary Medicine, National Pingtung University of Science and Technology, Pingtung, Taiwan.
Fish Shellfish Immunol. 2021 Apr;111:36-48. doi: 10.1016/j.fsi.2020.11.009. Epub 2021 Jan 11.
Francisella noatunensis subsp. orientalis (Fno) is a gram-negative intracellular bacterium identified in many fish species worldwide, including cultured Nile tilapia (Oreochromis niloticus) in Taiwan. To investigate the gene expression responses to Fno infection, we performed transcriptome analysis of the head kidney and spleen in Nile tilapia using RNA-seq. Total RNA was extracted from the head kidney and spleen of infected (Fno-injected) and uninfected (control) tilapia at 1-day and 2-days post-infection, and RNA-seq was performed using the Illumina HiSeq™ 4000 platform. After de novo assembly, a total of 106,534 transcripts were detected. These transcripts were annotated and categorized into a total of 7171 genes based on the KEGG pathway database. Differentially expressed genes (DEGs) were significantly (2-fold difference comparing Fno and PBS groups at each time point) enriched in the immune-related pathways, including the following: complement and coagulation cascades, cytokine-cytokine receptor interaction, hematopoietic cell lineage, lysosome, phagosome. We identified the upregulation of inflammatory cytokine-, apoptosis-, and neutrophil-related genes, and downregulation of complement- and lymphocyte-related genes. Additionally, we found the induction of natural resistance-associated macrophage protein 1 (NRAMP1) and heme responsive gene-1 (HRG1). Anemia of inflammation, caused by intracellular iron storage in spleen after Fno infection, was also observed. This study provides natural disease control strategies against Fno infection in tilapia. It is suggested that intercellular iron storage is a host protection strategy.
东方气单胞菌亚种（Fno）是一种革兰氏阴性细胞内细菌，已在全球许多鱼类物种中被发现，包括台湾养殖的尼罗罗非鱼（Oreochromis niloticus）。为了研究其对 Fno 感染的基因表达反应，我们使用 RNA-seq 对尼罗罗非鱼的头肾和脾脏进行了转录组分析。从感染（Fno 注射）和未感染（对照）尼罗罗非鱼的头肾和脾脏中提取总 RNA，在感染后 1 天和 2 天进行 RNA-seq，并使用 Illumina HiSeq™ 4000 平台进行。在从头组装后，共检测到 106534 个转录本。这些转录本基于 KEGG 途径数据库进行注释和分类，共分为 7171 个基因。差异表达基因（DEGs）在免疫相关途径中显著富集（每个时间点 Fno 和 PBS 组之间的差异倍数为 2 倍），包括以下途径：补体和凝血级联反应、细胞因子-细胞因子受体相互作用、造血细胞谱系、溶酶体、吞噬体。我们发现炎症细胞因子、凋亡和嗜中性粒细胞相关基因上调，而补体和淋巴细胞相关基因下调。此外，我们还发现了天然抗性相关巨噬细胞蛋白 1（NRAMP1）和血红素反应基因 1（HRG1）的诱导。在 Fno 感染后脾脏中细胞内铁储存引起的炎症性贫血也被观察到。本研究为罗非鱼对抗 Fno 感染提供了天然疾病控制策略。研究表明，细胞内铁储存是一种宿主保护策略。
