Key Laboratory of Tropical & Subtropical Fishery Resource Application & Cultivation, Ministry of Agriculture, Pearl River Fisheries Research Institute, Chinese Academy of Fishery Science, Guangzhou, 510380, China; Guangdong Provincial Key Laboratory of Aquatic Animal Immune Technology, Pearl River Fisheries Research Institute, Chinese Academy of Fishery Science, Guangzhou, 510380, China.
Key Laboratory of Tropical & Subtropical Fishery Resource Application & Cultivation, Ministry of Agriculture, Pearl River Fisheries Research Institute, Chinese Academy of Fishery Science, Guangzhou, 510380, China; College of Fisheries and Life Science, Shanghai Ocean University, Shanghai, 201306, China.
Dev Comp Immunol. 2022 Feb;127:104300. doi: 10.1016/j.dci.2021.104300. Epub 2021 Oct 18.
Toll-like receptors (TLRs) play a critical role in the innate immune response of fish. In this study, we isolated the cDNA sequence of Nile tilapia TLR1 (OnTLR1). The deduced OnTLR1 protein contains a signal peptide, 7 leucine-rich repeats (LRRs), a C-terminal LRR (LRR-CT), a transmembrane region and a highly conserved TIR domain. In healthy Nile tilapia, the OnTLR1 transcript was broadly expressed in all examined tissues, with the highest expression levels in the spleen. After infection with Streptococcus agalactiae, the OnTLR1 transcripts were upregulated in the gill and kidney. After stimulation with polyinosinic-polycytidylic acid (poly(I:C)), the expression levels of OnTLR1 were significantly downregulated in the intestine, whereas OnTLR1 transcripts were significantly upregulated in the kidney. After challenge with lipopolysaccharide (LPS), the expression levels of OnTLR1 were significantly upregulated in the spleen and kidney. The subcellular localization showed that OnTLR1 was expressed in the cytoplasm. TLR1 significantly increased MyD88-dependent NF-κB activity. However, the results of a pull-down assay showed that OnTLR1 did not interact with MyD88 or TIRAP. Binding assays revealed the specificity of OnTLR1 for pathogen-associated molecular patterns (PAMPs) and bacteria that included S. agalactiae, Aeromonas hydrophila and poly(I:C) and LPS. Taken together, these findings suggest that OnTLR1, as a pattern recognition receptor (PRR), might play an important role in the immune response to pathogen invasion.
Toll 样受体 (TLRs) 在鱼类的先天免疫反应中发挥着关键作用。在这项研究中，我们分离了尼罗罗非鱼 TLR1（OnTLR1）的 cDNA 序列。推断的 OnTLR1 蛋白包含一个信号肽、7 个富含亮氨酸的重复序列 (LRRs)、一个 C 端 LRR（LRR-CT）、一个跨膜区域和一个高度保守的 TIR 结构域。在健康的尼罗罗非鱼中，OnTLR1 转录本广泛表达于所有检测到的组织中，在脾脏中表达水平最高。在感染无乳链球菌后，OnTLR1 转录本在鳃和肾脏中上调。在用多聚肌苷酸-多聚胞苷酸 (poly(I:C)) 刺激后，OnTLR1 的表达水平在肠道中显著下调，而在肾脏中 OnTLR1 转录本显著上调。在用脂多糖 (LPS) 攻击后，OnTLR1 的表达水平在脾脏和肾脏中显著上调。亚细胞定位表明 OnTLR1 表达于细胞质中。TLR1 显著增加了 MyD88 依赖性 NF-κB 活性。然而，下拉实验的结果表明 OnTLR1 与 MyD88 或 TIRAP 不相互作用。结合实验揭示了 OnTLR1 对病原体相关分子模式 (PAMPs) 和细菌的特异性，包括无乳链球菌、嗜水气单胞菌、poly(I:C) 和 LPS。综上所述，这些发现表明，作为模式识别受体 (PRR) 的 OnTLR1 可能在对病原体入侵的免疫反应中发挥重要作用。
