转录组分析揭示溶藻弧菌感染早期大黄鱼的免疫应答特征

TRANSCRIPTOME ANALYSIS REVEALED THE IMMUNE RESPONSE OF LARGE YELLOW CROAKER(LARIMICHTHYS CROCEA)IN EARLY STAGE OF VIBRIO ALGINOLYTICUS INFECTION

为探究大黄鱼(Larimichthys crocea)抗溶藻弧菌(Vibrio alginolyticus)感染的免疫应答机制,研究通过转录组测序及生物信息学分析的手段,在转录组水平分析了溶藻弧菌感染24h后大黄鱼头肾中基因表达水平的变化,共获得1903个差异表达基因(Differentially expressed genes,DEGs),其中641个上调表达基因,1262个下调表达基因。通过Gene Ontology(GO)和Kyoto encyclopedia of genes and genomes(KEGG)富集分析发现,一些先天性免疫相关基因,包括补体(C1qbp、C1QL2和C7)、热休克蛋白(hspd1、hspa4、hspa5和hspa9)、抗菌肽(Hepcidin-1)、C型凝集素受体(Clec4e和MR1)、己糖激酶(hex1)、精氨酸酶(Arg-II)和线粒体翻译延伸因子(TUFM)等基因表达水平均显著上调;而许多与获得性免疫相关基因,包括T、B淋巴细胞增殖分化(FcR5和CCL17)、T细胞调控(TCRα、TCRβ、CD3ε、CD3γδ、CD3ζ、ZAP-70和ITK)及免疫球蛋白参与抗原识别(Ighv 5A、Ighv 914和Ighv XIG14)等基因表达水平均显著下调。结果表明,在感染早期,大黄鱼先天性免疫在抵御溶藻弧菌感染中发挥重要作用,而此时获得性免疫受到了抑制。

In order to investigate the immune response mechanism of large yellow croaker(Larimichthys crocea)against Vibrio alginolyticus infection,the transcriptome changes in head kidney 24h after infection were analyzed by high-throughput sequencing and bioinformatic analysis.A total of 1903 differentially expressed genes(DEGs)were obtained,of which 641 were up-regulated and 1262 were down-regulated.After Gene Ontology(GO)and Kyoto encyclopedia of genes and genomes(KEGG)enrichment analysis,the results showed that some innate immune-related genes,including complement(C1qbp,C1QL2 and C7),heat shock protein(hspd1,hspa4,hspa5 and hspa9),antimicrobial peptide(Hepcidin-1),C-type lectin receptor(Clec4e and MR1),hexokinase(hex1),arginase(Arg-II),and Tu translation elongation factor(TUFM)were significantly up-regulated.While many adaptive immune-related genes,including T and B cell proliferation and differentiation(FcR5 and CCL17),T cell regulatory factors(TCRα,TCRβ,CD3ε,CD3γδ,CD3ζ,ZAP-70 and ITK),and antigen recognition factors of Immunoglobulin(Ighv 5A,Ighv 914 and Ighv XIG14)were significantly down-regulated.Besides,GO terms related to aerobic metabolism,like Hemoglobin complex,Oxygen binding and Oxygen carrier activity also got significant enrichment,of which all DEGs were down-regulated in infection group.The results indicated that in the early stage of V.alginolyticus infection,the innate immunity of large yellow croaker was activated,while the adaptive immunity was inhibited.Since the late activation of adaptive immunity,in early stage of bacterial infection,the blocking of TCR signal pathway,and the inhibition of proliferation and differentiation of specific immonocytes might save enough energy for innate immunity,which was beneficial to the immune response of fish against bacterial infection.Our results also showed that after V.alginolyticus infection,oxygen transfer ability of large yellow croaker was decreased,which might be related to the hemolytic activity of the bacterium.