Scavenger receptors play a central role in defending against infectious diseases in mammals. However, the function of SRECII remains unknown in teleost fish. In this study, type F scavenger receptor expressed by endothelial cells-II (SRECII) cDNA sequence was first identified from Epinephelus coioides, named EcSRECII, which contained an N-terminal signal peptide, eight EGF/EGF-like cysteine-rich motifs and a C-terminal low-complexity region. The gene location maps revealed that EcSRECII has the conservation of synteny among selected species. Subcellular localization showed that EcSRECII was mainly located in the cytoplasm in HEK293T cells and GS cells. In healthy E. coioides, EcSRECII mRNA was highly expressed in spleen, skin, gill, thymus and head kidney. The relative EcSRECII mRNA expression after Vibrio parahaemolyticus infection was significantly up-regulated at 12 h in spleen, head kidney and thymus, but downregulated at 1 d in skin and reduced at 3 d and 1 w in spleen. Furthermore, overexpression of EcSRECII activated NF-κB and IFN-β signaling pathway in vitro. Taken together, these results indicated that EcSRECII could be as the potential pathogen recognition receptor for involving in bacterial infection by regulating innate immunity responses in E. coioides.

中文翻译：

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大肠杆菌（Epinephelus coioides）的内皮细胞（SREC）-II表达的F型清除剂受体在对副溶血性弧菌感染的免疫应答中是潜在的病原体识别受体。

清道夫受体在抵抗哺乳动物的传染病中起着重要作用。但是，在硬骨鱼中，SRECII的功能仍然未知。在这项研究中，内皮细胞-II（SRECII）cDNA序列表达的F型清道夫受体首先从大肠钩虫（Epinephelus coioides）中鉴定出来，名为EcSRECII，它包含一个N端信号肽，八个EGF / EGF样富含半胱氨酸的基序和C端低复杂度区域。基因定位图显示，EcSRECII在选定物种之间具有同义性保守性。亚细胞定位表明EcSRECII主要位于HEK293T细胞和GS细胞的细胞质中。在健康的大肠杆菌中，EcSRECII mRNA在脾脏，皮肤，腮，胸腺和头肾中高度表达。副溶血性弧菌感染后的相对EcSRECII mRNA表达在脾脏，头部肾脏和胸腺中在12 h时显着上调，但在皮肤中1 d下调，在脾脏3 d和1 w时降低。此外，EcSRECII的过表达在体外激活了NF-κB和IFN-β信号通路。综上所述，这些结果表明，EcSRECII可以通过调节大肠杆菌中的先天免疫应答而成为参与细菌感染的潜在病原体识别受体。