Project description:Traditional toxicity testing has been unable to keep pace with the introduction of new chemicals into commerce. Consequently, there are limited or no toxicity data upon which to base a risk assessment for many chemicals to which fish and wildlife may be exposed. Per- and polyfluoroalkyl substances (PFAS) are emblematic of this issue in that most the ecological hazards of most PFAS remain uncharacterized. The present study employed a high throughput assay to identify the concentration at which 20 PFAS, with diverse properties, elicited a concerted gene expression response in larval fathead minnows (Pimephales promelas, 5-6 days post-fertilization) exposed for 24 h. Based on a reduced transcriptome approach that measured whole body expression of 1832 genes, the median transcriptomic point of departure (tPOD) for the 20 PFAS tested was 10 µM. Longer chain carboxylic acids (12-13 C-F) and an eight C-F di-alcohol, N-alkyl sulfonamide, and telomer sulfonic acid were among the most potent PFAS, eliciting gene expression responses at concentrations below 1 µM. With a few exceptions, larval fathead minnow tPODs were concordant with those based on whole transcriptome response in human cell lines. However, larval fathead minnow tPODs were often greater than those for Daphnia magna exposed to the same PFAS. The tPODs overlapped concentrations at which other sub-lethal effects have been reported in fish (available for 10 PFAS; including a range of species, life stages, and study designs). Nonetheless, fathead minnow tPODs were all orders of magnitude higher than aqueous PFAS concentrations detected in tributaries of the North American Great Lakes suggesting a substantial margin of safety in those systems, even for PFAS with significant potential for bioaccumulation. Overall, results broadly support the use of a fathead minnow larval transcriptomics assay to derive screening level potency estimates for use in ecological risk-based prioritization. Traditional toxicity testing has been unable to keep pace with the introduction of new chemicals into commerce. Consequently, there are limited or no toxicity data upon which to base a risk assessment for many chemicals to which fish and wildlife may be exposed. Per- and polyfluoroalkyl substances (PFAS) are emblematic of this issue in that most the ecological hazards of most PFAS remain uncharacterized. The present study employed a high throughput assay to identify the concentration at which 20 PFAS, with diverse properties, elicited a concerted gene expression response in larval fathead minnows (Pimephales promelas, 5-6 days post-fertilization) exposed for 24 h. Based on a reduced transcriptome approach that measured whole body expression of 1832 genes, the median transcriptomic point of departure (tPOD) for the 20 PFAS tested was 10 µM. Longer chain carboxylic acids (12-13 C-F) and an eight C-F di-alcohol, N-alkyl sulfonamide, and telomer sulfonic acid were among the most potent PFAS, eliciting gene expression responses at concentrations below 1 µM. With a few exceptions, larval fathead minnow tPODs were concordant with those based on whole transcriptome response in human cell lines. However, larval fathead minnow tPODs were often greater than those for Daphnia magna exposed to the same PFAS. The tPODs overlapped concentrations at which other sub-lethal effects have been reported in fish (available for 10 PFAS; including a range of species, life stages, and study designs). Nonetheless, fathead minnow tPODs were all orders of magnitude higher than aqueous PFAS concentrations detected in tributaries of the North American Great Lakes suggesting a substantial margin of safety in those systems, even for PFAS with significant potential for bioaccumulation. Overall, results broadly support the use of a fathead minnow larval transcriptomics assay to derive screening level potency estimates for use in ecological risk-based prioritization.
Project description:RNA-seq expression assays were done in larval Pimephales promelas (Fathead minnow, FHM) exposed to 10 chemicals (3 metals, 4 Neonicotinoids, and 3 pharmaceuticals) over a range of concentrations to derive relatively short term transcriptomics based points of departure (tPODs). tPODs were compared to apical points of departures (aPODs) to investigate the potential use of the FHM tPODS as part of a high throughput approach that might be used in a regulatory context.
Project description:It is postulated that below a transcriptomic-based point of departure, adverse effects are unlikely to occur, thereby providing a chemical concentration to use in screening level hazard assessment. The present study extends previous work describing a high throughput fathead minnow assay that can provide full transcriptomic data after exposure to a test chemical. One day post-hatch fathead minnows were exposed to ten concentrations of three representatives of four chemical modes of action: organophosphates, ecdysone receptor agonists, plant photosystem II inhibitors, and estrogen receptor agonists for 24 hours. Concentration response modeling was performed on whole body gene expression data from each exposure, using measured chemical concentrations when available. Transcriptomic points of departure in larval fathead minnow were lower than apical effect concentrations across fish species but not always lower than toxic effect concentrations in other aquatic taxa like crustaceans and insects. The point of departure was highly dependent on measured chemical concentration which were often lower than the nominal concentration. Differentially expressed genes between chemicals within modes of action were compared and often showed statistically significant overlap. In addition, reproducibility between identical exposures using a positive control chemical (CuSO4) and variability associated with the transcriptomic point of departure using in-silico sampling were considered. Results extend a transcriptomic-compatible fathead minnow high throughput assay for possible use in ecological hazard screening.
Project description:Omics approaches are broadly used to explore endocrine and toxicity-related pathways and functions. Nevertheless, there is still a significant gap in knowledge in terms of understanding the endocrine system and its numerous connections and intricate feedback loops, especially in non-model organisms. The fathead minnow (Pimephales promelas) is a widely used small fish model for aquatic toxicology and regulatory testing, particularly in North America. A draft genome has been published but the amount of available genomic or transcriptomic information is still far behind that of other more broadly studied species, such as the zebrafish. Here, we surveyed the tissue-specific proteome and transcriptome profiles in adult male fathead minnow. To do so, we generated a draft transcriptome using short and long sequencing reads. We also performed RNA sequencing and proteomics analysis on the telencephalon, hypothalamus, liver, and gut of male fish. The main purpose of this analysis was to generate tissue-specific omics data in order to support future aquatic ecotoxicogenomic and endocrine-related studies as well as to improve our understanding of the fathead minnow as an ecological model.
Project description:Given that larval fish stages provide opportunities for development of stressor-selective screening level tests, this work aimed to investigate the optimal age of fathead minnow larva and duration of exposure for the pharmaceutical, propranolol, found in the environment. Differentially expressed genes were studied as well as gene set enrichment analysis.
Project description:Nanoparticles are compounds of emerging concern with largely unknown risks for human and ecological health. It is crucial to evaluate their potential biological impact to prevent unintended adverse effects on human health and the environment. We analyzed the transcriptional effects of polyvinylpyrrolidone-coated silver nanoparticles (PVP-AgNPs) and silver nitrate (AgNO3) on the fathead minnow (Pimephales promelas) to understand their potential toxicity and adverse outcomes. We also tested the feasibility of the fathead minnow as an alternative species to elucidate potential adverse effects on humans. Fathead minnow females were exposed to either 4 µg/L of AgNO3 or 70 µg/L of PVP-AgNPs for 96h. Microarray analyses were performed on liver and brain. Functional analysis identified potential toxicity pathways and molecular initiating events (MIEs) that were confirmed with functional assays. Data suggested that AgNO3 and PVP-AgNPs had both common and distinct transcriptional effects. The nanoparticles were linked to neurotoxicity and oxidative stress, and identified as a dopamine receptor antagonist. Silver nitrate was also identified as a potential neurotoxicant and was confirmed as adrenergic and cannabinoid receptors antagonist. While silver nitrate and PVP-AgNPs were both potential neurotoxicants, they appeared to act through different MIEs. Fathead minnow is a promising alternative species to elucidate potential adverse effects of relevance to human health. We analyzed the transcriptional effects of polyvinylpyrrolidone-coated silver nanoparticles (PVP-AgNPs) and silver nitrate (AgNO3) on the fathead minnow (Pimephales promelas) to understand their potential toxicity and adverse outcomes. FHM were obtained from Aquatic Biosystems (Fort Collins, CO), held in aerated dechlorinated tap water and fed three times daily with Zeigler® AquaTox Feed Gardners, PA, USA). Fathead minnow females were exposed to either 4 µg/L of AgNO3 or 70 µg/L of PVP-AgNPs (Luna Innovations, Blackburn, VA) for 96h at 24°C ± 1 with a 90% water change at 48 hours. Microarray analyses were performed on liver and brain.
Project description:Nanoparticles are compounds of emerging concern with largely unknown risks for human and ecological health. It is crucial to evaluate their potential biological impact to prevent unintended adverse effects on human health and the environment. We analyzed the transcriptional effects of polyvinylpyrrolidone-coated silver nanoparticles (PVP-AgNPs) and silver nitrate (AgNO3) on the fathead minnow (Pimephales promelas) to understand their potential toxicity and adverse outcomes. We also tested the feasibility of the fathead minnow as an alternative species to elucidate potential adverse effects on humans. Fathead minnow females were exposed to either 4 µg/L of AgNO3 or 70 µg/L of PVP-AgNPs for 96h. Microarray analyses were performed on liver and brain. Functional analysis identified potential toxicity pathways and molecular initiating events (MIEs) that were confirmed with functional assays. Data suggested that AgNO3 and PVP-AgNPs had both common and distinct transcriptional effects. The nanoparticles were linked to neurotoxicity and oxidative stress, and identified as a dopamine receptor antagonist. Silver nitrate was also identified as a potential neurotoxicant and was confirmed as adrenergic and cannabinoid receptors antagonist. While silver nitrate and PVP-AgNPs were both potential neurotoxicants, they appeared to act through different MIEs. Fathead minnow is a promising alternative species to elucidate potential adverse effects of relevance to human health.
Project description:In this study, fathead minnow (FHM) embryos were exposed to two doses of fresh, aged and pure naphthenic acids mixtures until hatch. Larvae were scored for developmental deformities prior to preservation for gene expression analyses. 5 larvae were pooled per gene expression replicate.
Project description:This experiment was conducted as part of an overall study aimed at examining effects of a dopamine receptor antagonist on reproduction, behavior, and gene expression in cyprinid fish. Relative to gene expression, we hypothesized that if haloperidol disrupted normal regulation of the HPG axis, there may be robust transcriptional alterations in the ovary of exposed females that might serve as useful markers of exposure and/or effects. For the purposes of this study, robust transcriptional alterations were defined as those detected in two separate fish species (fathead minnow and zebrafish), exposed to the same concentration of haloperidol for the same duration. There is a companion fathead minnow microarray experiment (GSE15115) that these data are compared to. Transcriptional responses in the ovary of the two species are compared in terms of differentially expressed genes, enriched gene ontology categories they represent, and associated pathways.