College of Agronomy Liaocheng University, Liaochen, 252000, China; Aquaculture Research Lab, College of Animal Science and Veterinary Medicine, Shandong Agricultural University, Taian, 271018, China.
Aquaculture Research Lab, College of Animal Science and Veterinary Medicine, Shandong Agricultural University, Taian, 271018, China.
Fish Shellfish Immunol. 2022 Aug;127:611-622. doi: 10.1016/j.fsi.2022.06.069. Epub 2022 Jul 6.
In invertebrates, several genes controlled by the Toll and immunodeficiency (IMD) signaling cascade are altered during microbial infection. However, little is known about the expression patterns of innate immune response genes in red-clawed crayfish (Cherax quadricarinatus). In the present study, the transcription of five genes was assessed in C. quadricarinatus challenged with Vibrio parahaemolyticus (V. parahaemolyticus). The expression of Relish, Toll-like receptor (TLR), tumor necrosis factor receptor-related factor 6 (TRAF6), Akirin, and IMD in different tissues and at different time points after infection were assessed. In addition, the Relish gene was amplified, the protein conformation of the Relish gene was predicted, and gene expression changes associated with antimicrobial peptide production in C. quadricarinatus were analyzed using RNA interference (RNAi). During V. parahaemolyticus infection, the transcripts of the above five genes were significantly increased in the hepatopancreas of C. quadricarinatus (P < 0.05). In contrast, TLR was significantly downregulated in muscle tissue at the initial stage of infection (P < 0.05); TRAF6 and IMD were significantly down-regulated throughout infection (P < 0.05); Akirin transcripts had the lowest abundance at 24 h post-infection; Relish, IMD and Akirin genes were significantly up-regulated in gill tissue at the early stage of infection (P < 0.05); only TRAF6 was significantly up-regulated at 6, 24 and 48 h after infection. The Relish gene of C. quadricarinatus is closely related to the Exopalaemon carinicauda. When the Relish gene was knocked down by RNAi, the V. parahaemolyticus challenge showed that the mortality rate of the RANi group was significantly higher than that of the NC group; pathological sections showed that the hepatopancreatic tissue damage was the most severe 12 h after the interference; and the interference significantly inhibited IRF4, NF-κB, ALF, laccase, SOD1, and lectin genes. Therefore, it can be hypothesized that the Toll and IMD pathways are activated in C. quadricarinatus in response to bacterial infection and that genes associated with these pathways are differentially transcribed in different tissues. This study provides insights into the Toll and IMD signaling pathways and the spatiotemporal expression of key genes regulating bacterial infection resistance in C. quadricarinatus.
在无脊椎动物中，几种受 Toll 和先天免疫缺陷 (IMD) 信号级联控制的基因在微生物感染过程中发生改变。然而，关于红螯螯虾（Cherax quadricarinatus）先天免疫反应基因的表达模式知之甚少。本研究评估了 5 种基因在感染副溶血弧菌（Vibrio parahaemolyticus，V. parahaemolyticus）后红螯螯虾中的转录情况。检测了感染后不同时间点不同组织中 Relish、Toll 样受体（TLR）、肿瘤坏死因子受体相关因子 6（TRAF6）、Akirin 和 IMD 的表达。此外，扩增了 Relish 基因，预测了 Relish 基因的蛋白质构象，并通过 RNA 干扰（RNAi）分析了与抗菌肽产生相关的基因表达变化。在副溶血弧菌感染期间，红螯螯虾肝胰腺中上述 5 种基因的转录明显增加（P < 0.05）。相反，在感染初期 TLR 在肌肉组织中明显下调（P < 0.05）；TRAF6 和 IMD 整个感染过程中均下调（P < 0.05）；Akirin 转录物在感染后 24 小时时丰度最低；Relish、IMD 和 Akirin 基因在感染早期鳃组织中显著上调（P < 0.05）；只有 TRAF6 在感染后 6、24 和 48 小时时显著上调。红螯螯虾的 Relish 基因与中国对虾（Exopalaemon carinicauda）密切相关。当 Relish 基因被 RNAi 敲低时，副溶血弧菌攻毒表明 RNAi 组的死亡率明显高于 NC 组；病理切片显示，干扰后 12 小时肝胰腺组织损伤最严重；干扰显著抑制了 IRF4、NF-κB、ALF、漆酶、SOD1 和凝集素基因。因此，可以假设 Toll 和 IMD 途径在红螯螯虾中被激活以应对细菌感染，并且与这些途径相关的基因在不同组织中差异转录。本研究为 Toll 和 IMD 信号通路以及调控红螯螯虾细菌感染抗性的关键基因的时空表达提供了见解。
