斑点叉尾TLR5和TLR5S基因在不同病原诱导下的表达特征

Gene expression of TLR5 and TLR5S in channel catfish Ictalurus punctatus induced by different pathogens

中文关键词: 斑点叉尾鮰  先无免疫  TLR5  TLR5S  基因表达  病原

英文关键词: Ictalurus punctatus  Innate immune  TLR5  TLR5S  Gene expression  Pathogens

中文摘要:

      分别用迟钝爱德华氏菌Edwardsiella tarda、嗜水气单胞菌Aeromonas hydrophila、链球菌Streptococcus iniae和斑点叉尾呼肠孤病毒（channel catfish hemorrhage reovirus，CCRV）对斑点叉尾Ictalurus punctatus进行感染实验，取感染后0h、12h、24h、48h、72h和7d的头肾、肠、肝脏和脾脏，采用实时定量PCR方法检测了TLR5和TLR5S基因在这4种免疫相关组织中的时空表达特征，探讨它们与斑点叉尾先天免疫反应的关系。结果表明，链球菌和迟钝爱德华氏菌能够引起TLR5和TLR5S强烈的上调表达，其中以感染链球菌12h后TLR5S在头肾中的表达上调量最为显著，与对照组相比提高了132倍 (P<0.01)。在感染嗜水气单胞菌后的24h内TLR5和TLR5S基因的表达量上升，但随后却显示出了明显的下调趋势，而斑点叉尾呼肠孤病毒在TLR5和TLR5S基因表达中起到了明显的抑制作用，于大部分组织中表达下调。在感染12h的脾脏中，TLR5基因的表达量仅为对照组的0.017倍 (P<0.01)，而TLR5S基因表达量达到最低，仅为对照组的001倍 (P<0.01)。从不同的组织来看，TLR5在肠中的表达上调幅度最大，而TLR5S在头肾中的表达增幅最明显，如感染链球菌和迟钝爱德华氏菌12h后，TLR5在肠中的表达量分别增加了50.4倍 (P<0.01) 和14.8倍 (P<0.01)，TLR5S在头肾中的表达量分别上升了52.8倍 (P<0.01) 和132倍 (P<0.01)。以上结果进一步证明了TLR5和TLR5S基因在斑点叉尾先天免疫反应过程中发挥着非常重要的作用，同时在抗病原侵袭过程中表现出了一定的组织特异性和病原特异性。

英文摘要:

      Expression of channel catfish TLR5 and TLR5S genes in the head kidney, intestine, liver and spleen were analyzed by quantitative real time PCR method at 0 h, 12 h, 24 h, 48 h, 72 h and 7 d after infection with Edwardsiella tarda, Aeromonas hydrophila, Streptococcus iniae and channel catfish hemorrhage reovirus (CCRV), respectively. The results showed that TLR5 and TLR5S mRNAs were largely up-regulated by E. tarda and S. iniae and the most significant increase of TLR5S gene expression occurred in head kidney 12h after being challenged with S. iniae, which was 132-fold higher than the PBS control. After infection with A. hydrophila, TLR5 and TLR5S showed up regulation at 12h and 24h and obvious down-regulation at 48h to 7d post-infection. TLR5 and TLR5S genes expression were suppressed by infection with CCRV in most tissues. In spleen, the expression of TLR5 was 0.017-fold while TLR5S was only 0.01-fold compared with PBS control. Among the four immune-related different tissues, the expression of TLR5 and TLR5S showed significant up-regulation in intestine and head kidney. For example, after being challenged with E. tarda and S. iniae, at time point of 12h, the expression of TLR5 increased 50.4-fold and 14.8-fold respectively in intestine, and the expression of TLR5S increased 52.8-fold and 132-fold respectively in head kidney. All data suggested that TLR5 and TLR5S were involved in the immune response of channel catfish against the intracellular bacterial and virus pathogen in a tissue-specific and pathogen-specific manner, and further confirmed that both of them played significant roles in the channel catfish innate immunity.