A feedback loop involving FREP and NF-κB regulates the immune response of sea cucumber Apostichopus japonicus
A feedback loop involving FREP and NF-κB regulates the immune response of sea cucumber Apostichopus japonicus
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DOI：
10.1016/j.ijbiomac.2019.05.133
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发表时间：
2019-08-15
影响因子：
8.2
通讯作者：
Li, Chenghua
中科院分区：
文献类型：
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作者：
Jiang, Liting;Wei, Zhixin;Li, Chenghua
我们的前期工作表明，刺参纤维蛋白原相关蛋白（AjFREP）在天然免疫中起重要作用。为了了解AjFREP在A.因此，我们克隆了AjFREP启动子并表征了假定的转录因子结合基序。AjFREP启动子区跨越1365 bp，含有几个转录因子结合位点。全长序列和所有截短片段在HEK-293细胞中表现出高启动子活性。LPS暴露后P1（-1365/+16）的荧光素酶活性显著增加，表明启动子对LPS有反应。我们还发现在启动子区有两个潜在的NF-κ B结合位点，共转染实验证明第一个结合位点是AjFREP转录所必需的。进一步研究了AjFREP敲低后体内注射LPS后AjNF-κ B/Rel的表达。我们发现，与对照组相比，用LPS攻击沉默AjFREP后4和8 h，AjNF-kappa B/Rel转录显著降低，表明激活的AjFREP反过来影响免疫应答下的NF-κ B通路。这些结果为AjFREP的激活机制提供了新的见解，即，选择性改变AjFREP表达可能会预防A. - 是的(C)2019爱思唯尔B. V.保留所有权利。
Our previous work indicated that fibrinogen-related protein (AjFREP) from sea cucumber (Apostichopus japonicus) plays important roles in innate immunity. To understand AjFREP expression regulation in A. japonicus, we cloned the AjFREP promoter and characterized the putative transcription-factor binding motifs. The AjFREP promoter region spans 1365 bp, containing several transcription-factor binding sites. The full-length sequence and all truncated fragments exhibited high promoter activity in HEK-293 cells. Luciferase activity significantly increased for P1(-1365/+16) after LPS exposure, suggesting that the promoter responded to LPS. We also found that two potential NF-kappa B binding sites were involved in the promoter region, and co-transfection assay demonstrated that the first binding site was necessary for AjFREP transcription. The expression of AjNF-kappa B/Rel after AjFREP knock-down followed by LPS injection in vivo was further investigated. We found that AjNF-kappa B/Rel transcript significantly decreased after silencing AjFREP with LPS challenge compared with the control at 4 and 8 h, suggesting that activated AjFREP in turn affected the NF-kappa B pathway under immune responses. These results provided novel insights into the activation mechanism of AjFREP, i.e., that selectively changing AjFREP expression may prevent pathogen infection in A. japonicus. (C) 2019 Elsevier B.V. All rights reserved.