title: Characterisation of the transcriptome of male and female wild-type guppy brains with RNA-Seq and consequences of exposure to the pharmaceutical pollutant, 17α-ethinyl estradiol.
abstract: Waterways are increasingly being contaminated by chemical compounds that can disrupt the endocrinology of organisms. One such compound is 17α-ethinyl estradiol (EE2), a synthetic estrogen used in the contraceptive pill. Despite considerable research interest in the effects of EE2 on reproduction and gene expression, surprisingly, only a few studies have capitalised on technologies, such as next-generation sequencing (NGS), to uncover the molecular pathways related to EE2 exposure. Accordingly, using high-throughput sequencing technologies, the aim of our study was to explore the effects of EE2 on brain transcriptome in wild-type male and female guppy (Poecilia reticulata). We conducted two sets of experiments, where fish were exposed to EE2 (measured concentrations: 8ng/L and 38ng/L) in a flow-through system for 21days. The effects on the brain transcriptome on both males and females were assessed using Illumina sequencing (MiSeq and HiSeq) platform followed by bioinformatics analysis (edgeR, DESeq2). Here, we report that exposure to EE2 caused both up- and downregulation of specific transcript abundances, and affected transcript abundance in a sex-specific manner. Specifically, we found 773 transcripts, of which 60 were male-specific, 61 female-specific and 285 treatment-specific. EE2 affected expression of 165 transcripts in males, with 88 downregulated and 77 upregulated, while in females, 120 transcripts were affected with 62 downregulated and 58 upregulated. Finally, RT-qPCR validation demonstrated that expression of transcripts related to transposable elements, neuroserpin and heat shock protein were significantly affected by EE2-exposure. Our study is the first to report brain transcriptome libraries for guppies exposed to EE2. Not only does our study provide a valuable resource, it offers insights into the mechanisms underlying the feminizing effects on the brains of organisms exposed to environmentally realistic concentrations of EE2.
authors.affiliation: School of Biological Sciences, Monash University, 3800 Victoria, Australia; Environmental and Marine Biology, Åbo Akademi University, 20500 Turku, Finland. Electronic address: minna.saaristo@monash.edu.
authors.forename: Minna
authors.initials: M
authors.lastname: Saaristo
authors.affiliation: School of Biological Sciences, Monash University, 3800 Victoria, Australia.
authors.forename: Bob B M
authors.initials: BBM
authors.lastname: Wong
authors.affiliation: Life Sciences, Glasgow Caledonian University, Glasgow G4 0BA, UK.
authors.forename: Laura
authors.initials: L
authors.lastname: Mincarelli
authors.affiliation: Life Sciences, Glasgow Caledonian University, Glasgow G4 0BA, UK.
authors.forename: Allison
authors.initials: A
authors.lastname: Craig
authors.affiliation: School of Biological Sciences, Monash University, 3800 Victoria, Australia.
authors.forename: Christopher P
authors.initials: CP
authors.lastname: Johnstone
authors.affiliation: Victorian Centre for Aquatic Pollution Identification and Management (CAPIM), School of Chemistry, 3010 Victoria, Australia.
authors.forename: Mayumi
authors.initials: M
authors.lastname: Allinson
authors.affiliation: Environmental and Marine Biology, Åbo Akademi University, 20500 Turku, Finland.
authors.forename: Kai
authors.initials: K
authors.lastname: Lindström
authors.affiliation: Life Sciences, Glasgow Caledonian University, Glasgow G4 0BA, UK.
authors.forename: John A
authors.initials: JA
authors.lastname: Craft
mesh_terms: D000818:Animals; D001921:Brain / Q000187:drug effects / Q000378:metabolism*; D016000:Cluster Analysis; D004997:Ethinyl Estradiol / Q000633:toxicity*; D005260:Female; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation / Q000187:drug effects; D015723:Gene Library; D008297:Male; D058977:Molecular Sequence Annotation; D011036:Poecilia / Q000235:genetics*; D016133:Polymerase Chain Reaction; D025341:Principal Component Analysis; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D017423:Sequence Analysis, RNA / Q000379:methods*; D059467:Transcriptome / Q000187:drug effects / Q000235:genetics*; D014874:Water Pollutants, Chemical / Q000633:toxicity*
chemical_list: D012333:RNA, Messenger; D014874:Water Pollutants, Chemical; D004997:Ethinyl Estradiol
keywords: Brain; EE2; Endocrine disrupting chemicals; Next generation sequencing; Poecilia reticulata; Transcriptome