School of Marine Science and Engineering, Qingdao Agricultural University, Qingdao 266109, China.
Shandong Province Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China.
Int J Mol Sci. 2023 Jun 26;24(13):10665. doi: 10.3390/ijms241310665.
Mannose receptor, as a member of the C-type lectin superfamily, is a non-canonical pattern recognition receptor that can internalize pathogen-associated ligands and activate intracellular signaling. Here, a mannose receptor gene, LvMR, was identified from the Pacific white shrimp . LvMR encoded a signal peptide, a fibronectin type II (FN II) domain, and two carbohydrate-recognition domains (CRDs) with special EPS and FND motifs. LvMR transcripts were mainly detected in the hepatopancreas, and presented a time-dependent response after pathogen challenge. The recombinant LvMR (rLvMR) could bind to various PAMPs and agglutinate microorganisms in a Ca-dependent manner with strong binding ability to -mannose and -acetyl sugars. The knockdown of LvMR enhanced the expression of most NF-κB pathway genes, inflammation and redox genes, while it had no obvious effect on the transcription of most phagocytosis genes. Moreover, the knockdown of LvMR caused an increase in reactive oxygen species (ROS) content and inducible nitric oxide synthase (iNOS) activity in the hepatopancreas after infection. All these results indicate that LvMR might perform as a PRR in immune recognition and a negative regulator of inflammation during bacterial infection.
甘露糖受体作为 C 型凝集素超家族的一员，是一种非经典的模式识别受体，能够内化病原体相关配体并激活细胞内信号。本文从凡纳滨对虾中鉴定出一个甘露糖受体基因 LvMR。LvMR 编码一个信号肽、一个纤维连接蛋白 II （FN II）结构域和两个具有特殊 EPS 和 FND 基序的碳水化合物识别结构域（CRD）。LvMR 转录本主要在肝胰腺中检测到，并在病原体攻击后表现出时间依赖性反应。重组 LvMR（rLvMR）可以与各种 PAMP 结合，并在 Ca2+依赖性方式下凝集微生物，对 -甘露糖和 -乙酰糖具有很强的结合能力。LvMR 的敲低增强了大多数 NF-κB 通路基因、炎症和氧化还原基因的表达，而对大多数吞噬基因的转录没有明显影响。此外，LvMR 的敲低导致在 感染后肝胰腺中活性氧（ROS）含量和诱导型一氧化氮合酶（iNOS）活性增加。所有这些结果表明，LvMR 可能在细菌感染过程中作为免疫识别的 PRR 和炎症的负调节剂发挥作用。
