Diclofenac exposure alter the expression of PXR and its downstream target genes in mosquito fish (Gambusia affinis)
Diclofenac exposure alter the expression of PXR and its downstream target genes in mosquito fish (Gambusia affinis)
复制标题
双氯芬酸暴露改变蚊鱼 (Gambusia affinis) PXR 及其下游靶基因的表达
DOI：
10.1016/j.scitotenv.2017.10.305
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发表时间：
2018-03-01
影响因子：
9.8
通讯作者：
Liu, Sijia
中科院分区：
文献类型：
--
作者：
Bao, Shuang;Nie, Xiangping;Liu, Sijia
As one of widely used drugs, Diclofenac (DCF) recently has been universally detected in aquatic environment and some negative effects derived from DCF exposure to mammals have been also reported. However, studies about its potential deleterious effects on non-target organisms like fish still require more investigation. In this study an ubiquitous small freshwater invader species in Southern of China, mosquito fish (Gambusia affinis), was employed as test organism. We firstly cloned the crucial partial sequences of nucleus transcriptional factor related genes pregnane X receptor (PXR) and its downstream genes, including P-glycoprotein (P-gp), cytochrome 3A (CYP3A), multidrug resistance protein 2 (MRP2), glutathione peroxidase (GPx) and thioredoxin reductase (TXR) in mosquito fish. The phylogenetic trees of PXR, CYP3A and MRP2 were constructed based on their deduced amino acids sequences, respectively. Phylogenetic trees and blast results showed a high similarity between G. affinis and other killifish species, such as Xiphophorus maculatus. The transcriptional expression of these genes mentioned above and partly related enzymes/proteins activities were then measured under the exposure of environmentally relevant concentrations of DCF (from 0.5 mu g L-1 to 500 mu g L-1) for 24 h and 168 h. Results showed that the mRNA expression of PXR, CYP3A, P-gp and TXR showed dramatic induction under DCF exposure, exhibiting an obvious time-effect relationship with the extend of exposure time. In terms of enzyme activity and protein content, no dramatic changes as in transcription were observed. Western blotting showed PXR protein increased at 24 h but decreased at 168 h with the increasing of DCF concentration, displaying a dose-effect relationship to some extent. GPX activitywas continuously induced both at 24 h and 168 h, exhibiting a good consistency with the performance of GPX gene. GSSH/T-GSH increased in all treatments. Overall, DCF had traceable effects on the expression of PXR and its downstream target genes in mosquito fish. (c) 2017 Elsevier B.V. All rights reserved.
