A serotonin receptor (Cg5-HTR-1) mediating immune response in oyster Crassostrea gigas

Serotonin receptors, including ligand-gated ion channel (LGICs) and G protein-coupled receptors (GPCR), play vital roles in modulating physiological processes and immunoreaction. In the present study, a homologue of serotonin (5-HT) receptor was identified from oyster Crassostrea gigas (designated C...

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Bibliographic Details
Published in:Developmental & Comparative Immunology
Main Authors: Jia, Yunke, Yang, Bin, Dong, Wenjing, Liu, Zhaoqun, Lv, Zhao, Jia, Zhihao, Qiu, Limei, Wang, Lingling, Song, Linsheng
Format: Report
Language:English
Published: ELSEVIER SCI LTD 2018
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Online Access:http://ir.qdio.ac.cn/handle/337002/158365
https://doi.org/10.1016/j.dci.2017.12.029
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Summary:Serotonin receptors, including ligand-gated ion channel (LGICs) and G protein-coupled receptors (GPCR), play vital roles in modulating physiological processes and immunoreaction. In the present study, a homologue of serotonin (5-HT) receptor was identified from oyster Crassostrea gigas (designated Cg5-HTR1). Its open reading frame (ORF) was of 1239 bp, encoding-a polypeptide of 412 amino acids with a seven transmembrane region. Cg5-HTR-1 shared high similarity with the 5-HTRs from other animals. The cAMP contents in HEK293T cells decreased significantly after Cg5-HTR-1 transfection and 5-HT incubation (p < .05), while blocking Cg5-HTR-1 with specific receptor antagonist reversed this downtrend. The intracellular Ca2+ concentrations increased significantly (p < .05) after cell transfection and 5-HT incubation, and the antagonist treatment also arrested this process. Cg5-HTR-1 transcripts were widely distributed in various tissues, with the highest level in hepatopancreas and lowest level in mantle and gill. The mRNA expression of Cg5-HTR-1 in hemocyte increased significantly after lipopolysaccharide (LPS) stimulation and reached the peak level (6.47-fold, p < .05) at 6 h post treatment. The inhibition of Cg5-HTR-1 significantly reduced the expression of tumor necrosis factor (TNF) mRNA in hemocyte, down-regulated the superoxide dismutase (SOD) activity in serum, and induced the apoptosis of hemocyte (p < .05). These results suggested that Cg5-HTR-1 was a novel member of 5-HT1 receptor family and it mediated serotonergic immunomodulation on both cellular and humoral immune responses. (C) 2018 Elsevier Ltd. All rights reserved.