Transcriptome network data in larval zebrafish (Danio rerio) following exposure to the phenylpyrazole fipronil

Abstract

Fipronil is a phenylpyrazole pesticide that is used in both residential and agricultural applications. Fipronil is detected in run-off and water systems that are near areas in which the pesticide has been applied. The pesticide acts to antagonize gamma aminobutyric acid receptors, leading to over-excitation in the central nervous system. Fipronil has relatively high toxicity to fish, but the mechanisms underlying the toxicity are not well understood in embryonic stages. Zebrafish embryos were exposed to a single concentration of fipronil for 48 h at ∼3-4 h-post-fertilization. Following a 7-day depuration phase, transcriptome and behavioral analyses were conducted. Transcriptomics identified neural processes as those differentially expressed with different doses of fipronil (0.2 µg, 200 µg and 2 mg fipronil/L). Gene networks associated with astrocyte differentiation, myelination, neural tube development, brain stem response, innervation, nerve regeneration, astrocyte differentiation, among other pathways were altered with exposure. In addition, miRNA-related events are disrupted by fipronil exposure and genes associated with primary or pri-miRNA processing were increased in larval fish exposed to the pesticide. These data present putative mechanisms associated with neurological impacts at later ages of zebrafish. This is important because it is not clear how early exposure to pesticides like fipronil affect central nervous system function and organisms later in life.

Keywords: Agrochemical; Environmental toxicology; Gene network; Neurotoxicity; Pesticide.

Fig. 1

Venn diagrams for the number of gene sets (GSEA, left graph) and subnetworks (SNEA, right graph) affected in fish exposed to each of the three concentrations of fipronil. These computational methods represent two separate bioinformatics approaches used to discern molecular pathways. Units of concentrations are in µg/L.

Fig. 2

Gene network for cell processes affected in larval fish by fipronil exposure. Red indicates that the gene is increased in expression relative to the control and blue indicates a down-regulation. Data from the 200 µg fipronil/L exposure were used to build the network. Abbreviations are reported in Supplemental Data 1.

Fig. 3

Gene network for a primary or pri-miRNA network affected in larval fish by fipronil exposure. Red indicates that the gene is increased in expression relative to the control and blue indicates a down-regulation. Data from the 200 µg fipronil/L exposure were used to build the network. Abbreviations are reported in Supplemental Data 1.