A new non-phagocytic TLR6 with broad recognition ligands from Pacific oyster Crassostrea gigas
A new non-phagocytic TLR6 with broad recognition ligands from Pacific oyster Crassostrea gigas
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一种新的非吞噬细胞 TLR6，具有来自太平洋牡蛎巨牡蛎的广泛识别配体
DOI：
10.1016/j.dci.2016.07.010
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发表时间：
2016-12-01
影响因子：
2.9
通讯作者：
Song, Linsheng
中科院分区：
文献类型：
--
作者：
Wang, Weilin;Zhang, Tao;Song, Linsheng
Toll样受体（Toll like receptor, TLRs）是动植物界进化中普遍存在的识别分子，在免疫防御和体内平衡维持中起着重要作用。近年来，在无脊椎动物基因组中发现了扩增的tlr，但扩增的tlr的特性和免疫功能尚不清楚。本研究在长牡蛎中发现了一个具有5个LRR结构域的TLR家族新成员（命名为CgTLR6）。它与其他生物的tlr具有同源性，与软体动物的tlr具有最密切的系统发育关系。重组蛋白CgTLR6 （rCgTLR6）对革兰氏阴性菌安古拉弧菌和脾弧菌、革兰氏阳性菌金黄色葡萄球菌和黄体微球菌以及真菌毕赤酵母具有直接结合活性，而对多脂耶氏菌不具有直接结合活性。对脂多糖（LPS）和肽聚糖（PGN）也有亲和力，而对甘露聚糖（MAN）没有亲和力。CgTLR6 mRNA主要存在于牡蛎的血细胞和肝胰腺中，LPS、PGN和脾弧菌刺激后，其在牡蛎的血细胞中被显著诱导（p < 0.01）。免疫荧光分析表明，CgTLR6主要位于血细胞膜上。抗rcgtlr6抗体阻断CgTLR6后，血细胞对已识别的革兰氏阴性细菌V. anguillarum和V. splendidus以及未识别的真菌Y. lipolytica的吞噬率没有明显抑制。这些结果共同表明，CgTLR6是一种新的非吞噬受体，通过识别病原体相关的分子模式来介导gigas的体液免疫反应。(C) 2016 Elsevier Ltd.版权所有。
Toll like receptors (TLRs) are evolutionarily prevalent recognition molecules in the Animalia and Plantae kingdom, which play vital roles in immune defense and homeostasis maintenance. Recently, the expansion of TLRs has been reported in invertebrate genomes, but the characters and immune functions of these expanded TLRs were still not well known. In the present study, a new member of TLR family with five LRR domains was identified in Crassostrea gigas (designated CgTLR6). It shared homology with TLRs from other organisms with the closest phylogenic relationship with molluscan TLRs. The recombinant protein of CgTLR6 (rCgTLR6) displayed direct bind activity to gram-negative bacteria Vibrio anguillarum and Vibrio splendidus, gram-positive bacteria Staphylococci aureus and Micrococcus luteus, and fungi Pichia pastoris, but not to fungi Yarrowia lipolytica. It also exhibited affinity to lipopolysaccharide (LPS) and peptidoglycan (PGN), while no affinity to mannan (MAN). The mRNA of CgTLR6 was mainly detected in hemocytes and hepatopancreas, and was significantly induced (p < 0.01) in hemocytes after the oyster was stimulated with LPS, PGN or bacteria V. splendidus. Immunofluorescence analysis indicated that CgTLR6 was mainly located at the membrane of hemocytes. The blockage of CgTLR6 by anti-rCgTLR6 antibody did not significantly inhibit the phagocytic rates of hemocytes toward recognized gram negative bacteria V. anguillarum and V. splendidus, and unrecognized fungi Y. lipolytica. These results collectively implied that CgTLR6 was a novel non-phagocytic receptor of C. gigas to mediate humoral immune response by recognizing pathogen-associated molecular patterns on the invaders. (C) 2016 Elsevier Ltd. All rights reserved.