Expression and functional characterization of the mannose receptor (MR) from Nile tilapia (Oreochromis niloticus) in response to bacterial infection
Expression and functional characterization of the mannose receptor (MR) from Nile tilapia (Oreochromis niloticus) in response to bacterial infection
复制标题
尼罗罗非鱼 (Oreochromis niloticus) 甘露糖受体 (MR) 响应细菌感染的表达和功能特征
DOI：
10.1016/j.dci.2021.104257
复制
发表时间：
2021-09-15
影响因子：
2.9
通讯作者：
Ye, Jianmin
中科院分区：
文献类型：
--
作者：
Yin, Xiaoxue;Bai, Hao;Ye, Jianmin
甘露糖受体(MR)作为模式识别受体(PRRs)的一员，在免疫应答中发挥着重要作用。在哺乳动物中，MR在调节吞噬作用中的作用已被阐明；然而，在硬骨鱼中，其对调理吞噬作用的贡献仍不清楚。本研究探讨了尼罗罗非鱼甘露糖受体基因(OnMR)的表达模式及其对单核/巨噬细胞吞噬病原菌的调节作用。OnMR开放阅读框全长4314bp，编码1437个氨基酸残基的多肽。推导的氨基酸序列表明，onMR含有一个富含半胱氨酸的结构域、一个纤维连接蛋白II型结构域、多个C型凝集素样结构域、一个跨膜区和一个短的细胞质结构域。组织分布分析表明，onMR转录本广泛分布于所检测的10个组织中，且在头肾、后肾、肠和脾中高表达。无乳链球菌和嗜水气单胞菌感染后，头肾和脾组织中onMR的表达显著增加。此外，在体外感染细菌和甘露糖液后，MO/Mo中onMR的表达也上调。提示MR作为巨噬细胞表面的甘露糖受体，可能对病原菌的刺激有强烈的反应。此外，(R)onMR蛋白能有效结合和凝集无乳链球菌和嗜水气单胞菌，调节单核/巨噬细胞对病原菌的吞噬能力。这些结果表明，onMR参与了尼罗罗非鱼对细菌感染的应答，这一研究将有助于我们更好地了解MR在硬骨鱼中的功能。
Mannose receptor (MR) as a member of the pattern recognition receptors (PRRs) plays an important role in the immune response. In mammals, the role of MR in the regulation of phagocytosis is clarified; however, its contribution to opsonize phagocytosis remains unclear in bony fish. In this study, the expression pattern of Nile tilapia mannose receptor gene (OnMR) was investigated and its regulation of the phagocytosis of monocytes/ macrophages to pathogenic bacteria was identified. The full-length of OnMR open reading frame is 4314 bp, encoding a peptide containing 1437 amino acid residues. The deduced amino acid sequence revealed that OnMR contained a cysteine-rich domain, a fibronectin type II domain, multiple C-type lectin-like domains, a transmembrane domain and a short cytoplasmic domain. Tissue distribution analysis showed the OnMR transcripts was widely distribute in the ten detected tissues, and highly expressed in head kidney, hind kidney, intestine and spleen. After S. agalactiae and A. hydrophila infection, the expression of OnMR in head kidney and spleen increased significantly. Moreover, the expression of OnMR in MO/Mo were also upregulated post the infection of bacteria and mannose solutions in vitro. This suggested that MR, as a mannose receptor on macrophage surface, could respond strongly to the stimulation of pathogenic bacteria. In addition, the (r)OnMR protein could effectively bind and agglutinate S. agalactiae and A. hydrophila, and regulate the phagocytic ability of monocytes/ macrophages to pathogenic bacteria. These results suggest that OnMR is involved in response against bacterial infection in Nile tilapia, and this study will help us better understand the function of MR in teleost fish.