Altered gene expression in the brain and liver of female fathead minnows exposed to fadrozole
Ontology highlight
ABSTRACT:
ORGANISM(S): Pimephales promelas
PROVIDER: GSE10722 | GEO | 2008/08/21
SECONDARY ACCESSION(S): PRJNA107611
REPOSITORIES: GEO
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Project description:The fathead minnow (Pimephales promelas) is a small fish species widely used for ecotoxicology research and regulatory testing in North America. This study used a 2000 gene oligonucleotide microarray to evaluate the effects of the aromatase inhibitor, fadrozole, on gene expression in the liver and brain tissue of exposed females. Reproductive measures, plasma vitellogenin, and gene expression data for the brain isoform of aromatase (CYP19B), vitellogenin precursors, and transferrin all provided evidence supporting the efficacy of the fadrozole exposure. Unsupervised analysis of the microarray results identified 20 genes in brain and 41 in liver as significantly up-regulated and 7 genes in brain and around 45 in liver as significantly down-regulated. Differentially expressed genes were associated with a broad spectrum of biological functions, many with no obvious relationship to aromatase inhibition. However, in brain, fadrozole exposure elicited significant up-regulation of several genes involved in the cholesterol synthesis, suggesting it as one potentially impacted pathway. Gene ontology-based analysis of expression changes in liver suggested overall down-regulation of protein biosynthesis. While real-time PCR analyses supported some of the microarray responses, others could not be verified. Overall, results of this study provide a foundation for developing novel hypotheses regarding the system-wide effects of fadrozole, and other chemical stressors with similar modes of action, on fish biology. Keywords: chemical stress response --Fadrozole exposure-- Treatments: 0, 60 ug fadrozole/L Replication: 4 replicate tanks per treatment, 2 replicate pairs (1 male, one female per pair) per tank for a total of 8 male, 8 female per treatment. Route of exposure: Waterborne, continuous flow through, without the use of carrier solvents, flow rate approx. 45 ml/min. Tanks: 20 L tanks containing 10 L of exposure water Fadrozole (purity ⥠99%; Dr. H. Cooper Eckhardt, Summit, NJ, USA). Fish: Adult (ca. 6 month old) male (4.65±0.93 g) and female (1.90±0.44 g) Conditions: (25°C, 16:8 light:dark photoperiod, fed adult brine shrimp twice daily) Duration: 7 d (± 4 h) Sampling: Fish humanely euthanized in tricaine methanesulfonate (Finquel; Argent, Redmond, WA, USA). Liver, and brain samples transferred directly to pre-weighed vials of RNAlater® (Sigma, St. Louis, MO). Plasma samples were stored frozen at -80°C. Average water quality characteristics (±SD): temperature 25.5±0.1 °C; pH 7.21±0.04; dissolved oxygen 5.74±0.52 mg/L. --Microarray analysis-- n=3 microarrays per treatment and tissue Experimental samples: total RNA pooled from n=2 fish from the same treatment and replicate (except for pooled sample BC3 which included fish from two different replicate tanks). Reference sample: pooled liver, brain, and gonad samples from adult male and female fathead minnows Microarray design: Two color, reference design Hybridization: Experimental samples Cy5, reference sample Cy3
2010-05-22 | E-GEOD-10722 | biostudies-arrayexpress
Project description:Aromatase, a member of the cytochrome P450 superfamily, is a key enzyme in estrogen synthesis and is responsible for the aromatization of androgens into estrogens. Here, we used an integrated approach to better understand the effects of aromatase inhibition as well as the mechanisms involved in the adaptation and recovery process. We exposed female fathead minnows (Pimephales promelas) to 30 μg/L of a model aromatase inhibitor, fadrozole, during 8 days (exposure phase). Fish were then held in clean water for 8 more days (recovery phase). Samples were collected at 1, 2, 4, and 8 days of both the exposure and the recovery phase. We used transcriptomics, metabolomics, and network inference to understand changes and infer connections at the transcript and metabolite level in the ovary. Other apical endpoints such as plasma estradiol, testosterone, and vitellogenin levels were also measured. An integrated analysis of the data revealed changes in gene expression consistent with increased testosterone. Metabolites such as glycogen and taurine were strongly correlated with increased testosterone levels. Comparison of in vivo and ex vivo data suggested the accumulation of steroidogenic enzymes, including aromatase, as a mechanism to compensate for aromatase inhibition. We exposed female fathead minnows (Pimephales promelas) to 30 μg/L of a model aromatase inhibitor, fadrozole, during 8 days (exposure phase). Fish were then held in clean water for 8 more days (recovery phase). Samples were collected at 1, 2, 4, and 8 days of both the exposure and the recovery phase.
2013-11-01 | E-GEOD-51961 | biostudies-arrayexpress
Project description:Prochloraz is a fungicide known to cause endocrine disruption through effects on the hypothalamic-pituitary-gonadal (HPG) axis. To determine the short-term impacts of prochloraz on gene expression and steroid production, adult female fathead minnows (Pimephales promelas) were exposed to the chemical (0 or 300 μg/L) for a time-course of 6, 12 and 24 h. Consistent with inhibition of cytochrome P450 17α-hydroxylase/17,20-lyase (CYP17) and aromatase (CYP19), known molecular targets of prochloraz, plasma 17β-estradiol (E2) was reduced within 6 hours. Ex vivo E2 production was significantly reduced at all time-points, while ex vivo testosterone (T) production remained unchanged. Consistent with the decrease in E2 levels, plasma concentrations of the estrogen-responsive protein vitellogenin were significantly reduced at 24 h. Genes coding for CYP19, CYP17, and steroidogenic acute regulatory protein were up-regulated in a compensatory manner in ovaries of the prochloraz-treated fish. In addition to targeted quantitative real-time polymerase chain reaction analyses, a 15k feature fathead minnow microarray was used to determine gene expression profiles in ovaries. From time-point to time-point, the microarray results showed a relatively rapid change in the differentially expressed gene (DEG) profiles associated with the chemical exposure. Functional analysis of the DEGs indicated changes in expression of genes associated with cofactor and coenzyme binding (GO: 0048037 and 0050662), fatty acid binding (GO:0005504) and organelle organization and biogenesis (GO: 0006996). Overall, the results from this study are consistent with compensation of the fish HPG axis to inhibition of steroidogenesis by prochloraz, and provide further insights into relatively rapid, system-wide, effects of a model chemical stressor on fish.
2011-02-03 | GSE26958 | GEO
Project description:Aromatase, a member of the cytochrome P450 superfamily, is a key enzyme in estrogen synthesis and is responsible for the aromatization of androgens into estrogens. Here, we used an integrated approach to better understand the effects of aromatase inhibition as well as the mechanisms involved in the adaptation and recovery process. We exposed female fathead minnows (Pimephales promelas) to 30 μg/L of a model aromatase inhibitor, fadrozole, during 8 days (exposure phase). Fish were then held in clean water for 8 more days (recovery phase). Samples were collected at 1, 2, 4, and 8 days of both the exposure and the recovery phase. We used transcriptomics, metabolomics, and network inference to understand changes and infer connections at the transcript and metabolite level in the ovary. Other apical endpoints such as plasma estradiol, testosterone, and vitellogenin levels were also measured. An integrated analysis of the data revealed changes in gene expression consistent with increased testosterone. Metabolites such as glycogen and taurine were strongly correlated with increased testosterone levels. Comparison of in vivo and ex vivo data suggested the accumulation of steroidogenic enzymes, including aromatase, as a mechanism to compensate for aromatase inhibition.
2013-11-01 | GSE51961 | GEO
Project description:Interpreting proteomic and genomic data is a major challenge in predictive ecotoxicology that can be addressed by a systems biology approach. Mathematical modeling provides an organizational platform to consolidate protein dynamics with possible genomic regulation. Here, a model of ovarian steroidogenesis in the fathead minnow (Pimephales promelas) is developed to evaluate possible transcriptional regulation of the steroid production observed in microarray studies. Steroidogenesis, the production of sex steroids, is a highly conserved pathway whose regulation is critical to sexual reproduction. The model was developed from literature sources, integrating key signaling components (G-protein and PKA activation) with their ensuing effect on steroid production. The model properly predicted steroid behavior when fish were exposed to fadrozole, a specific aromatase inhibitor, but failed to predict testosterone and estradiol behavior during depuration. In vivo microarray data implicated three modes of regulation which may account for over-production of steroids during depuration: P450 enzyme up-regulation, inhibin down-regulation, or luteinizing hormone up-regulation. Simulation studies and sensitivity analysis were used to evaluate each of the three modes as possible sources of compensation.
2009-05-13 | GSE15924 | GEO
Project description:Cytochrome P450 aromatase is an essential enzyme for vertebrates. It is responsible for the conversion of androgens to estrogens in the brain and gonadal tissues. Aromatase converts testosterone into estradiol and therefore participates in the regulation of many processes which are controlled by estrogens such as development and fertility. Teleosts have been characterized as having exceptionally high levels of brain estrogen biosynthesis when compared to the brains of the other vertebrates. Little is known about the effects of estrogens on brain function in teleosts. The main objective of this study was to assess the effects of fadrozole, a powerful aromatase inhibitor, on gene expression in the zebrafish brain. To achieve this, male zebrafish were exposed to fadrozole for 10 days. This exposure causes a decrease in estrogens along with an increase in androgens. Plasma testosterone levels showed a 3-fold increase in response to the exposure. In the telencephalon, 235 genes were identified by Affymetrix GeneChip analysis as being differentially regulated. Real-time RT-PCR was used to validate the data obtained from the microarrays. This technique was also used to evaluate the response in the hypothalamus, which appears to follow similar transcriptional regulation. Gene ontology analysis of the microarray data revealed common biological processes and molecular functions such as sensory perception and detection of light stimulus, homeobox and transcription factor complexes. This study has identified genes which are directly and/or indirectly controlled by estrogens and androgens which helped to demonstrate the pronounced effects of endocrine disrupting chemicals on gene expression in the brain of teleosts. Collectively, the results provide a better understanding of the effects of aromatase inhibitors on gene expression and also shed light on the underlying effects of sex hormone variation and their importance in the brain of teleosts. Adult male zebrafish were exposed to fadrozole (200 ug/L) for 10 days. Telencephalons were pooled; approximately 30 per array. 3 treated samples, 3 control samples
2009-02-26 | E-GEOD-14718 | biostudies-arrayexpress
Project description:Cytochrome P450 aromatase is an essential enzyme for vertebrates. It is responsible for the conversion of androgens to estrogens in the brain and gonadal tissues. Aromatase converts testosterone into estradiol and therefore participates in the regulation of many processes which are controlled by estrogens such as development and fertility. Teleosts have been characterized as having exceptionally high levels of brain estrogen biosynthesis when compared to the brains of the other vertebrates. Little is known about the effects of estrogens on brain function in teleosts. The main objective of this study was to assess the effects of fadrozole, a powerful aromatase inhibitor, on gene expression in the zebrafish brain. To achieve this, male zebrafish were exposed to fadrozole for 10 days. This exposure causes a decrease in estrogens along with an increase in androgens. Plasma testosterone levels showed a 3-fold increase in response to the exposure. In the telencephalon, 235 genes were identified by Affymetrix GeneChip analysis as being differentially regulated. Real-time RT-PCR was used to validate the data obtained from the microarrays. This technique was also used to evaluate the response in the hypothalamus, which appears to follow similar transcriptional regulation. Gene ontology analysis of the microarray data revealed common biological processes and molecular functions such as sensory perception and detection of light stimulus, homeobox and transcription factor complexes. This study has identified genes which are directly and/or indirectly controlled by estrogens and androgens which helped to demonstrate the pronounced effects of endocrine disrupting chemicals on gene expression in the brain of teleosts. Collectively, the results provide a better understanding of the effects of aromatase inhibitors on gene expression and also shed light on the underlying effects of sex hormone variation and their importance in the brain of teleosts.
2009-02-26 | GSE14718 | GEO
Project description:Municipal wastewater effluent can impact its receiving environment. In the St. Lawrence River, male fish living downstream from Montreal exhibit increased hepatic vitellogenin, intersex, delayed spermatogenesis and altered immune function. Few studies have examined genome-wide effects associated with municipal effluent exposure in fish to decipher the mechanisms of toxicity. The present objective was to identify hepatic cellular signaling pathways in fathead minnows following exposure to municipal wastewater effluent. Immature minnows were exposed for 21 days to either 0% (Control) or 20% municipal effluent, the highest concentration in the St. Lawrence River. Hepatic RNA was extracted and used to hybridize a fathead minnow oligonucleotide microarray containing approximately 15K gene sequences.
2014-08-31 | GSE52693 | GEO
Project description:Prochloraz is a fungicide known to cause endocrine disruption through effects on the hypothalamic-pituitary-gonadal (HPG) axis. To determine the short-term impacts of prochloraz on gene expression and steroid production, adult female fathead minnows (Pimephales promelas) were exposed to the chemical (0 or 300 M-NM-<g/L) for a time-course of 6, 12 and 24 h. Consistent with inhibition of cytochrome P450 17M-NM-1-hydroxylase/17,20-lyase (CYP17) and aromatase (CYP19), known molecular targets of prochloraz, plasma 17M-NM-2-estradiol (E2) was reduced within 6 hours. Ex vivo E2 production was significantly reduced at all time-points, while ex vivo testosterone (T) production remained unchanged. Consistent with the decrease in E2 levels, plasma concentrations of the estrogen-responsive protein vitellogenin were significantly reduced at 24 h. Genes coding for CYP19, CYP17, and steroidogenic acute regulatory protein were up-regulated in a compensatory manner in ovaries of the prochloraz-treated fish. In addition to targeted quantitative real-time polymerase chain reaction analyses, a 15k feature fathead minnow microarray was used to determine gene expression profiles in ovaries. From time-point to time-point, the microarray results showed a relatively rapid change in the differentially expressed gene (DEG) profiles associated with the chemical exposure. Functional analysis of the DEGs indicated changes in expression of genes associated with cofactor and coenzyme binding (GO: 0048037 and 0050662), fatty acid binding (GO:0005504) and organelle organization and biogenesis (GO: 0006996). Overall, the results from this study are consistent with compensation of the fish HPG axis to inhibition of steroidogenesis by prochloraz, and provide further insights into relatively rapid, system-wide, effects of a model chemical stressor on fish. RNA samples for each treatment/time point combination were used for microarray analysis (total of 23 arrays). For the microarray work, total RNA was isolated from ovary samples using RNeasy kits (Qiagen, Valencia, CA, USA). The RNA quality was assessed with an Agilent 2100 Bioanalyzer (Agilent, Wilmington, DE, USA) and quantity was determined using a NanodropM-BM-. ND-1000 spectrophotometer. Total RNA was stored at -80oC until analyzed with oligonucleotide microarrays. Microarray analysis was conducted at the US Army Engineer Research and Development Center (Vicksburg, MS, USA) using a 15k feature fathead minnow microarray (GEO: http://www.ncbi.nlm.nih.gov/geo/; Accession platform number GPL9248) designed by Dr. Nancy Denslow (University of Florida, Gainesville, FL, USA) and manufactured by Agilent Technologies (Palo Alto, CA, USA). The Agilent one-color microarray hybridization protocol (One-Color Microarray-Based Gene Expression Analysis, version 5.7, Agilent Technologies) was used for microarray hybridizations. One M-BM-5g of total RNA was used for all hybridizations. The cDNA synthesis, cRNA labeling, amplification and hybridization were performed following the manufacturerM-bM-^@M-^Ys kits and protocols (Quick Amp Labeling kit; Agilent Technologies). An Axon GenePixM-BM-. 4000B Microarray Scanner (Molecular Devices Inc., Sunnyvale, CA, USA) was used to scan microarray images at 5 M-NM-<m resolution. Data were resolved from microarray images using Agilent Feature Extraction software (Agilent Technologies). Statistical analyses were conducted using Statistica 8 (StatSoft Inc., Tulsa, OK, USA) and GraphPad Instat v. 3.01 (GraphPad Software, San Diego, CA, USA). Data were tested for normality and homogeneity of variance. When data conformed to parametric assumptions, data were analyzed using a parametric one-way ANOVA with chemical treatment as the independent variable. When data did not conform to parametric assumptions, they were either transformed (log 10) or analyzed using a non-parametric KruskallM-bM-^@M-^SWallis test (pM-bM-^IM-$ 0.05). The data are presented as means with standard errors of the mean. Differences were considered significant at p M-bM-^IM-$ 0.05. Microarray data were imported into the Rosetta Resolver 7.2 system for gene expression analysis (Rosetta Biosoftware, Kirkland, WA, USA). Data were normalized using the default, text loader, intensity profile builder settings in the Rosetta Resolver system. Significantly DEGs were identified using one-way ANOVA (p < 0.01) with no multiple testing correction
2011-02-03 | E-GEOD-26958 | biostudies-arrayexpress
Project description:Effects of bisphenol A (BPA) on ovarian transcript profiles as well as targeted endpoints with endocrine/reproductive relevance were examined in two fish species, fathead minnow (Pimephales promelas) and zebrafish (Danio rerio), exposed in parallel using matched experimental designs. Four days of waterborne exposure to 10 µg BPA caused significant vitellogenin induction in both species. However, zebrafish were less sensitive to effects on hepatic gene expression and steroid production than fathead minnow and the magnitude of vitellogenin induction was more modest. The concentration-response at the ovarian transcriptome level was non-monotonic and violated assumptions that underlie proposed methods for estimating hazard thresholds from transcriptomic results. However, the non-monotonic profile was consistent among species and there were nominal similarities in the functions associated with the differentially expressed genes, suggesting potential activation of common pathway perturbation motifs in both species. Overall, the results provide an effective case study for considering the potential application of ecotoxicogenomics to ecological risk assessments and provide novel comparative data regarding effects of BPA in fish. Fish were exposed to 0, 0.01, 0.1, 1.0, 10, or 100 µg BPA/L delivered in a continuous flow (45 ml/min) of sand filtered, UV treated, Lake Superior Water, without the use of carrier solvents. The design employed six replicate tanks per treatment. Three of the replicates were loaded with three male and three female zebrafish per tank, while the remaining three replicates were loaded with three male and three female fathead minnows. Addition of fish to the exposure tanks was staggered by replicate such that all sampling could be completed within 60 min of the desired 96 h exposure duration. After 96 h of exposure, fish were anesthetized in a buffered solution of tricaine methanesulfonate (MS-222; Finquel; Argent, Redmond, WA, USA) and weighed. Blood was collected from the caudal vasculature using microhematocrit tubes, centrifuged to separate the plasma, and plasma was stored at -80oC until analyzed. Liver, gonad, and brain tissues (including pituitary gland) were snap frozen in liquid nitrogen and stored at -80oC until extracted. Total RNA was isolated from ovary tissue of both fathead minnow and zebrafish using RNeasy kits (Qiagen, Valencia, CA, USA). RNA quality was evaluated using an Agilent 2100 Bioanalyzer (Agilent, Wilmington, DE, USA) and RNA was quantified spectrophotometrically (Nanodrop). Total RNA samples were stored at -80oC until used for microarray analyses. Ovarian transcripts from 32 fathead minnows (n=5 per treatment, except for control and 1.0 µg BPA/L, n=6) were analyzed using a custom, 15,000 gene microarray (GEO Platform Accession GPL9248) purchased from Agilent Technologies (Palo Alto, CA, USA). Ovarian transcripts from 34 zebrafish (n=6 per treatment, except 0.01 and 0.1 µg BPA/L, n=5) were analyzed using a commercial 44,000 feature microarray (Agilent design 019161; GEO Platform Accession GPL6457). The same hybridization and scanning procedures were used for both platforms. Briefly, microarrays were hybridized following the manufacturer’s guidelines for One-Color Microarray-Based Gene Expression Analysis (version 5.7; Agilent). Hybridizations were conducted with 1 µg of total RNA. Complementary DNA synthesis, cRNA labeling, amplification, and hybridizations were performed following the manufacturer’s kits and protocols (Quick Amp labeling kit; Agilent). Scanning was conducted at 5 µm resolution using an Axon GenePix® 4000B Microarray Scanner (Molecular Devices Inc., Concord, Ontario, Canada). Data were extracted from microarray array images using Agilent Feature Extraction Software (Agilent; Palo Alto, CA, USA).
2012-01-01 | E-GEOD-28351 | biostudies-arrayexpress