State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei Province, China; University of Chinese Academy of Sciences, Beijing, China.
State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei Province, China; Key Laboratory of Aquaculture Disease Control, Ministry of Agriculture, Wuhan, Hubei Province, China; The Innovative Academy of Seed Design, Chinese Academy of Sciences, Beijing, China; University of Chinese Academy of Sciences, Beijing, China.
Fish Shellfish Immunol. 2019 Nov;94:355-372. doi: 10.1016/j.fsi.2019.09.040. Epub 2019 Sep 15.
Streptococcus agalactiae is a major aquaculture pathogen infecting various saltwater and freshwater fish. To better understand the mechanism of the immune responses to S. agalactiae in wildtype zebrafish, the transcriptomic profiles of two organs containing mucosal-associated lymphoid tissues from S. agalactiae-infected and non-infected groups were obtained using RNA-seq techniques. In the intestines, 6735 and 12908 differently expressed genes (DEGs) were identified at 24 hpi and 48 hpi, respectively. Among 66 and 116 significantly enriched pathways, 15 and 21 pathways were involved in immune system or signal transduction at 24 hpi and 48 hpi, respectively. A number of genes involved in Toll-like receptor signaling pathway, RIG-I-like receptor signaling pathway, NOD-like receptor signaling pathway, T cell receptor signaling pathway, B cell receptor signaling pathway, Antigen processing and presentation, NF-kappa B signaling pathway and PI3K-Akt signaling pathway were significantly downregulated. In the skins, 3113 and 4467 DEGs were identified at 24 hpi and 48 hpi, respectively. Among 24 and 56 significantly enriched pathways, 4 and 13 pathways were involved in immune system or signal transduction at 24 hpi and 48 hpi, respectively. More immune-related signaling pathways including Leukocyte transendothelial migration, Cytokine-cytokine receptor interaction, PI3K-Akt signaling pathway, IL-17 signaling pathway, MAPK signaling pathway, TNF signaling pathway, Complement and coagulation cascades, Hematopoietic cell lineage and Jak-STAT signaling pathway were differently enriched for upregulated DEGs at 48 hpi, which were completely different from that in the intestines. Furthmore, comparative transcriptome analysis revealed that the downregulated 1618 genes and upregulated 1622 genes existed both at 24 hpi and 48 hpi for the intestine samples. In the skins, the downregulated 672 genes and upregulated 428 genes existed both at 24 hpi and 48 hpi. Three pathways related to immune processes were significantly enriched for downregulated DEGs both in the intestines and skins collected at 24 hpi and 48 hpi, which included Antigen processing and presentation, Intestinal immune network for IgA production and Hematopoietic cell lineage. Interaction network analysis of DEGs identified the main DEGs in the sub-network of complement and coagulation cascades both in the intestines and skins. Twenty of DEGs involved in complement and coagulation cascades were further validated by Real-time quantitative PCR. Altogether, the results obtained in this study will provide insight into the immune response of zebrafish against S. agalactiae XQ-1 infection in fatal conditions, and reveal the discrepant expression pattern of complement and coagulation cascades in the intestines and skins.
无乳链球菌是一种主要的水产养殖病原体，感染各种海水和淡水鱼类。为了更好地了解野生型斑马鱼对无乳链球菌免疫反应的机制，我们使用 RNA-seq 技术获得了来自无乳链球菌感染和未感染组的两个含有黏膜相关淋巴组织的器官的转录组图谱。在肠道中，在 24 hpi 和 48 hpi 时分别鉴定出 6735 和 12908 个差异表达基因（DEGs）。在 66 和 116 个显著富集的途径中，在 24 hpi 和 48 hpi 时，分别有 15 和 21 个途径参与免疫系统或信号转导。许多参与 Toll 样受体信号通路、RIG-I 样受体信号通路、NOD 样受体信号通路、T 细胞受体信号通路、B 细胞受体信号通路、抗原加工和呈递、NF-κB 信号通路和 PI3K-Akt 信号通路的基因显著下调。在皮肤中，在 24 hpi 和 48 hpi 时分别鉴定出 3113 和 4467 个 DEGs。在 24 和 56 个显著富集的途径中，在 24 hpi 和 48 hpi 时，分别有 4 个和 13 个途径参与免疫系统或信号转导。更多与免疫相关的信号通路，包括白细胞跨内皮迁移、细胞因子-细胞因子受体相互作用、PI3K-Akt 信号通路、IL-17 信号通路、MAPK 信号通路、TNF 信号通路、补体和凝血级联、造血细胞谱系和 Jak-STAT 信号通路，在 48 hpi 时上调的 DEGs 中差异富集，这与肠道完全不同。此外，比较转录组分析显示，在 24 hpi 和 48 hpi 时，肠道样本中下调的 1618 个基因和上调的 1622 个基因同时存在。在皮肤中，在 24 hpi 和 48 hpi 时，下调的 672 个基因和上调的 428 个基因同时存在。在 24 hpi 和 48 hpi 时，与免疫过程相关的三个途径都显著富集下调的 DEGs，包括抗原加工和呈递、肠道免疫网络中 IgA 的产生和造血细胞谱系。DEGs 的相互作用网络分析鉴定了肠道和皮肤中补体和凝血级联亚网络中的主要 DEGs。20 个涉及补体和凝血级联的 DEGs 通过实时定量 PCR 进一步验证。总的来说，本研究的结果将为斑马鱼在致命条件下对抗无乳链球菌 XQ-1 感染的免疫反应提供深入了解，并揭示肠道和皮肤中补体和凝血级联的差异表达模式。
