Project description:Deltamethrin (Del) is a widely administered pyrethroid insecticide that is established as a common contaminant of the freshwater environment and can be detected in many freshwater ecosystems even at lower concentrations. In this study, we investigated the changes in brain transcriptome and metabolome of crucian carp after exposure to 0.6 μg/L Del for 28 days. Antioxidant system analysis revealed that Del exposure significantly increases MDA concentration, and the activity of SOD was significantly inhibited in the brain (p < 0.05). Moreover, a total of 70 differential metabolites (DMs) were identified by the liquid chromatography-mass spectrometry (LC-MS/MS) system analysis, including 32 upregulated and 38 downregulated DMs in the DG group. The DMs associated with chronic Del exposure were enriched in steroid hormone biosynthesis, fatty acid metabolism, and glycerophospholipid metabolisms, such as prostaglandin G2, 5-oxoeicosatetraenoic acid, progesterone, androsterone, etiocholanolone, and hydrocortisone. Simultaneously, transcriptomics analysis revealed that chronic Del exposure caused lipid metabolism disorder, endocrine disruption, and proinflammatory immune response by upregulating the pla2g4, cox2, log5, ptgis, lcn, and cbr gene expression. Importantly, the integrative analysis of transcriptomics and metabolomics indicated that the arachidonic acid (AA) metabolism pathway and steroid hormone biosynthesis were decisive pathways in the brain tissue of crucian carp after Del exposure. Further, Del exposure perturbed the tight junction, HIF-1 signaling pathway, and thyroid hormone signaling pathway. Overall, transcriptome and metabolome data in our study offer a new insight to assess the risk of chronic Del exposure in fish brains.
Project description:Fish gills represent a complex organ that perform multiple physiological functions and is composed of several cell types. Among these cells, ionocytes are implicated in the maintenance of ion homeostasis. However, because the ionocyte represents only a small percent of whole gill tissue, its specific transcriptome can be overlooked among the numerous cell types included in the gill. The objective of this study is to better understand ionocyte functions by comparing the RNA expression of this cell type in freshwater and seawater adapted rainbow trout. To realize this objective, ionocytes were captured from gill cryosections using laser capture microdissection after immunohistochemistry. Then, transcriptome analyses were performed on an Agilent trout oligonucleotide microarray. Gene expression analysis identified 108 unique annotated genes differentially expressed between freshwater and seawater ionocytes, with a gene fold higher than 3. Most of these genes were up regulated in freshwater cells. Interestingly, several genes implicated in ion transport, extracellular matrix and structural cellular proteins appeared up regulated in freshwater ionocytes. Among them, several ion transporters, such as CIC2, SLC26A6, and NBC, were validated by qPCR and/or in situ hybridization. The latter technique allowed us to localize the transcripts of these ion transporters in only ionocytes and more particularly in the freshwater cells. Genes involved in metabolism and also several genes implicated in transcriptional regulation, cell signaling and the cell cycle were also over-expressed in freshwater ionocytes. In conclusion, laser capture microdissection combined with microarray analysis allowed for the determination of the cell signature of scarce cells in fish gills, such as ionocytes, and aided characterization of the transcriptome of these cells in freshwater and seawater adapted trout.