Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Ministry of Education, Shanghai Ocean University, Shanghai, 201306, China; National Pathogen Collection Center for Aquatic Animals, Shanghai Ocean University, Shanghai, 201306, China.
Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Ministry of Education, Shanghai Ocean University, Shanghai, 201306, China; National Pathogen Collection Center for Aquatic Animals, Shanghai Ocean University, Shanghai, 201306, China.
Fish Shellfish Immunol. 2020 Dec;107(Pt A):84-94. doi: 10.1016/j.fsi.2020.10.003. Epub 2020 Oct 7.
Toll-like receptors, which are a class of cell-surface proteins, have been regarded as the most important pattern recognition receptors in the innate immunity and play a vital role in multiple innate immune responses against pathogen invasion. The full-length cDNA of a novel Toll-like receptor (MrToll3) was identified from Macrobrachium rosenbergii in the current research. The nucleotide sequence of MrToll3 is 4481 bp long and contains a 3726-bp open reading frame encoding a putative protein of 1241 amino acids. MrToll3 was constitutively expressed in all the examined tissues, and high expression of MrToll3 was detected in gill, heart, and ganglion. The result of RNA interference assay revealed that silencing of MrToll1 remarkably suppressed the prophenoloxidase (proPO) expression and phenoloxidase (PO) activities while enhancing MrToll2 expression in the prawns. Furthermore, the expression of myeloid differentiation factor 88 (MyD88), anti-lipopolysaccharide factor (ALF) and crustin was remarkably down-regulated in the MrToll1-silenced prawns after white spot syndrome virus (WSSV) or Vibrio alginolyticus challenge. MrToll2-silenced prawns exhibited the significant decline of ALF and crustin expression post the pathogen challenges, and silencing of MrToll3 obviously improved the immune deficiency (IMD) expression during the whole RNA interference assay. Additionally, higher mortality was observed in MrToll1-or MrToll2-silenced prawns after V. alginolyticus challenge, and the MrToll1-silenced prawns also showed the obviously enhanced susceptibility to WSSV. These results suggested that MrToll1, 2, and 3 were involved in the innate immune responses against WSSV and V. alginolyticus in M. rosenbergii.
Toll 样受体是一类细胞表面蛋白，被认为是固有免疫中最重要的模式识别受体，在多种针对病原体入侵的固有免疫反应中发挥着重要作用。本研究从罗氏沼虾中鉴定出一种新型 Toll 样受体（MrToll3）的全长 cDNA。MrToll3 的核苷酸序列长 4481bp，包含一个 3726bp 的开放阅读框，编码一个推测的 1241 个氨基酸的蛋白质。MrToll3 在所有检测的组织中均持续表达，在鳃、心脏和神经节中检测到 MrToll3 的高表达。RNA 干扰试验的结果表明，MrToll1 的沉默显著抑制了对虾原酚氧化酶（proPO）的表达和酚氧化酶（PO）的活性，同时增强了 MrToll2 的表达。此外，在 MrToll1 沉默的对虾中，髓样分化因子 88（MyD88）、抗脂多糖因子（ALF）和几丁质酶的表达在受到白斑综合征病毒（WSSV）或溶藻弧菌攻击后显著下调。在受到病原体攻击后，MrToll2 沉默的对虾中 ALF 和几丁质酶的表达显著下降，MrToll3 沉默则明显改善了整个 RNA 干扰试验期间的免疫缺陷（IMD）表达。此外，在受到溶藻弧菌攻击后，MrToll1 或 MrToll2 沉默的对虾死亡率更高，MrToll1 沉默的对虾对 WSSV 的敏感性也明显增强。这些结果表明，MrToll1、2 和 3 参与了罗氏沼虾对 WSSV 和溶藻弧菌的固有免疫反应。
