Investigating RDX neurotoxicity in rat brain using gene expression analysis and transcriptional network modeling
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ABSTRACT:
ORGANISM(S): Rattus norvegicus
SUBMITTER: Mitchell Wilbanks
PROVIDER: E-GEOD-27042 | biostudies-arrayexpress |
REPOSITORIES: biostudies-arrayexpress
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Project description:ABSTRACT: The central nervous system is remarkably plastic in its ability to recover from trauma. We examined recovery from hexahydro-1,3,5-trinitrotriazine (RDX) induced seizures in rat through changes in transcriptional networks. Transcriptional networks from time series experiments provide a good basis for organizing and studying the dynamic behavior of biological processes. The goal of this work was to identify networks affected by chemical exposure and track changes in these networks as animals recover. We examined brain microarray data from rats exposed to 0, 1.2, 12, 24, and 47 mg RDX/kg body weight at different time points after exposure (24hr, 48hr, 7d, 14d, 28d and 90d). RESULTS A credible transcriptional network was constructed from the gene expression microarray data, which predicts the role of some key genes such as heat shock proteins, neuropeptide Y, thyrotropin-releasing hormones, growth factors, and ion channels in neurotransmission and neuroprotective mechanisms. Examination of the dynamic changes in expression within this network over time provided insight into CNS protective mechanisms from traumas.
2011-05-31 | GSE27042 | GEO
Project description:We investigated ecotoxicological effects and toxicogenomic responses in fathead minnows (Pimephales promelas) exposed to an environmentally-relevant concentration (0.83 mg/L) of the munitions compound cyclotrimethylenetrinitramine (RDX) in one year and multi-generational assays. In the one year assay, RDX effects were discerned by comparing breeding groups reared in control or RDX-exposure conditions for one year. RDX had no detectable effect on gonad-somatic index, or condition factor in females assayed at 1 day and at 1, 3, 6, 9, and 12 months, however the liver-somatic index was significantly increased versus controls only at the 12 month time point. RDX had no effect on live-prey capture rates at all time points assayed and no significant impacts on egg production, fertilization or hatch success in the 1-year exposure trial. Genomic analyses indicated that RDX exposure caused limited differential expression of transcripts within time points and no functional conservation of effects indicative of RDX exposure among time points for either brain or liver tissues in the one year exposure. In the multi-generational assay, the effects of acute (96h) exposure to RDX were compared in fish reared to the F2 generation in either control or RDX-exposure conditions. The RDX-reared fish were not observed to have appreciably enhanced RDX tolerance versus the control-reared fish. However, significant differences in gene expression were observed among the control and RDX-reared fish related to neuro-excitatory glutamate metabolism, sensory signaling and processes in neurological development. In total, our results indicate that exposure to an RDX concentration approximating maximum levels observed in the field (0.83 mg/L) caused limited impacts in fathead minnows in a one year exposure, however caused altered expression in genes involved in neural function in a multi-generational exposure.
2010-07-30 | GSE21102 | GEO
Project description:We investigated ecotoxicological effects and toxicogenomic responses in fathead minnows (Pimephales promelas) exposed to an environmentally-relevant concentration (0.83 mg/L) of the munitions compound cyclotrimethylenetrinitramine (RDX) in one year and multi-generational assays. In the one year assay, RDX effects were discerned by comparing breeding groups reared in control or RDX-exposure conditions for one year. RDX had no detectable effect on gonad-somatic index, or condition factor in females assayed at 1 day and at 1, 3, 6, 9, and 12 months, however the liver-somatic index was significantly increased versus controls only at the 12 month time point. RDX had no effect on live-prey capture rates at all time points assayed and no significant impacts on egg production, fertilization or hatch success in the 1-year exposure trial. Genomic analyses indicated that RDX exposure caused limited differential expression of transcripts within time points and no functional conservation of effects indicative of RDX exposure among time points for either brain or liver tissues in the one year exposure. In the multi-generational assay, the effects of acute (96h) exposure to RDX were compared in fish reared to the F2 generation in either control or RDX-exposure conditions. The RDX-reared fish were not observed to have appreciably enhanced RDX tolerance versus the control-reared fish. However, significant differences in gene expression were observed among the control and RDX-reared fish related to neuro-excitatory glutamate metabolism, sensory signaling and processes in neurological development. In total, our results indicate that exposure to an RDX concentration approximating maximum levels observed in the field (0.83 mg/L) caused limited impacts in fathead minnows in a one year exposure, however caused altered expression in genes involved in neural function in a multi-generational exposure.
2010-07-30 | GSE21101 | GEO
Project description:We investigated ecotoxicological effects and toxicogenomic responses in fathead minnows (Pimephales promelas) exposed to an environmentally-relevant concentration (0.83 mg/L) of the munitions compound cyclotrimethylenetrinitramine (RDX) in one year and multi-generational assays. In the one year assay, RDX effects were discerned by comparing breeding groups reared in control or RDX-exposure conditions for one year. RDX had no detectable effect on gonad-somatic index, or condition factor in females assayed at 1 day and at 1, 3, 6, 9, and 12 months, however the liver-somatic index was significantly increased versus controls only at the 12 month time point. RDX had no effect on live-prey capture rates at all time points assayed and no significant impacts on egg production, fertilization or hatch success in the 1-year exposure trial. Genomic analyses indicated that RDX exposure caused limited differential expression of transcripts within time points and no functional conservation of effects indicative of RDX exposure among time points for either brain or liver tissues in the one year exposure. In the multi-generational assay, the effects of acute (96h) exposure to RDX were compared in fish reared to the F2 generation in either control or RDX-exposure conditions. The RDX-reared fish were not observed to have appreciably enhanced RDX tolerance versus the control-reared fish. However, significant differences in gene expression were observed among the control and RDX-reared fish related to neuro-excitatory glutamate metabolism, sensory signaling and processes in neurological development. In total, our results indicate that exposure to an RDX concentration approximating maximum levels observed in the field (0.83 mg/L) caused limited impacts in fathead minnows in a one year exposure, however caused altered expression in genes involved in neural function in a multi-generational exposure.
2010-07-30 | GSE21100 | GEO
Project description:We investigated ecotoxicological effects and toxicogenomic responses in fathead minnows (Pimephales promelas) exposed to an environmentally-relevant concentration (0.83 mg/L) of the munitions compound cyclotrimethylenetrinitramine (RDX) in one year and multi-generational assays. In the one year assay, RDX effects were discerned by comparing breeding groups reared in control or RDX-exposure conditions for one year. RDX had no detectable effect on gonad-somatic index, or condition factor in females assayed at 1 day and at 1, 3, 6, 9, and 12 months, however the liver-somatic index was significantly increased versus controls only at the 12 month time point. RDX had no effect on live-prey capture rates at all time points assayed and no significant impacts on egg production, fertilization or hatch success in the 1-year exposure trial. Genomic analyses indicated that RDX exposure caused limited differential expression of transcripts within time points and no functional conservation of effects indicative of RDX exposure among time points for either brain or liver tissues in the one year exposure. In the multi-generational assay, the effects of acute (96h) exposure to RDX were compared in fish reared to the F2 generation in either control or RDX-exposure conditions. The RDX-reared fish were not observed to have appreciably enhanced RDX tolerance versus the control-reared fish. However, significant differences in gene expression were observed among the control and RDX-reared fish related to neuro-excitatory glutamate metabolism, sensory signaling and processes in neurological development. In total, our results indicate that exposure to an RDX concentration approximating maximum levels observed in the field (0.83 mg/L) caused limited impacts in fathead minnows in a one year exposure, however caused altered expression in genes involved in neural function in a multi-generational exposure. P. promelas larvae produced in the original one year exposure were collected and grown out to sexual maturity while being maintained in the same treatment (control or 0.83 mg/L RDX) as their respective F0 parental generation. Once the fish reached sexual maturity, they were placed into eight experimental units for both control and RDX treatment consisting of four females and two males and were maintained with the same experimental conditions as the F0 generation. To determine if the chronic, multi-generational exposure to RDX resulted in any change in sensitivity to RDX, 90 dph progeny (F2 or sub-adults) of the control and RDX-exposed F1 generation were subjected to a challenge experiment where the fish were exposed to RDX at 5 mg/L.
2010-07-30 | E-GEOD-21102 | biostudies-arrayexpress
Project description:We investigated ecotoxicological effects and toxicogenomic responses in fathead minnows (Pimephales promelas) exposed to an environmentally-relevant concentration (0.83 mg/L) of the munitions compound cyclotrimethylenetrinitramine (RDX) in one year and multi-generational assays. In the one year assay, RDX effects were discerned by comparing breeding groups reared in control or RDX-exposure conditions for one year. RDX had no detectable effect on gonad-somatic index, or condition factor in females assayed at 1 day and at 1, 3, 6, 9, and 12 months, however the liver-somatic index was significantly increased versus controls only at the 12 month time point. RDX had no effect on live-prey capture rates at all time points assayed and no significant impacts on egg production, fertilization or hatch success in the 1-year exposure trial. Genomic analyses indicated that RDX exposure caused limited differential expression of transcripts within time points and no functional conservation of effects indicative of RDX exposure among time points for either brain or liver tissues in the one year exposure. In the multi-generational assay, the effects of acute (96h) exposure to RDX were compared in fish reared to the F2 generation in either control or RDX-exposure conditions. The RDX-reared fish were not observed to have appreciably enhanced RDX tolerance versus the control-reared fish. However, significant differences in gene expression were observed among the control and RDX-reared fish related to neuro-excitatory glutamate metabolism, sensory signaling and processes in neurological development. In total, our results indicate that exposure to an RDX concentration approximating maximum levels observed in the field (0.83 mg/L) caused limited impacts in fathead minnows in a one year exposure, however caused altered expression in genes involved in neural function in a multi-generational exposure. Adult fathead minnows were exposed to 0.83 mg/L (0.15 mg/L standard deviation) in experimental units including 2 male and 4 fish. Five replicate males were randomly sampled with replacement from each of 8 control and 8 RDX-exposed experimental units at 1d, 1mo, 3mo, 6mo, 9mo and 12mo sampling periods. Liver tissue was investigated for differential expression in response to RDX exposure.
2010-07-30 | E-GEOD-21100 | biostudies-arrayexpress
Project description:RDX (Hexahydro-1,3,5-trinitro-1,3,5-triazine) is a synthetic, high-impact, relatively stable explosive that has been in use since WWII. Exposure to RDX can occur either occupationally or through ordnance that lays unexploded on training ranges. The toxicology of RDX is dominated by acute tonic-clonic seizures at high doses, which remit when exposure is removed and internal RDX levels decrease. Sub-chronic studies have revealed few other toxic effects. The objective of this study was to examine the effect of a single oral dose of RDX on global gene expression in the mammalian brain and liver, using a rodent model. Keywords: time course, dose response
2009-03-13 | GSE12196 | GEO
Project description:This SuperSeries is composed of the following subset Series: GSE21100: One Year RDX Exposure, Liver Tissue Investigation GSE21101: One Year RDX Exposure, Brain Tissue Investigation GSE21102: Sub-adult RDX Exposure, Whole Body Tissue Investigation Refer to individual Series
2010-07-30 | E-GEOD-21103 | biostudies-arrayexpress
Project description:Production, usage and disposal of the munitions constituent (MC) cyclotrimethylenetrinitramine (RDX) has led to environmental releases on military facilities. The chemical attributes of RDX are conducive for leaching to surface water which may put aquatic organisms at risk of exposure. Because RDX has been observed to cause aberrant neuromuscular effects across a wide range of animal phyla, we assessed the effects of RDX on central nervous system (CNS) function in the representative aquatic ecotoxicological model species, fathead minnow (Pimephales promelas). A brain-tissue based cDNA library enriched for transcripts differentially expressed in response to RDX exposure was developed for fathead minnow and was transitioned to custom cDNA-based microarrays. All 4,128 cDNAs were sequenced, quality filtered and assembled yielding 3,018 unique sequences and 945 significant blastx matches (E ≤ 10-5). Bioassays were conducted exposing fathead minnows to RDX at 0.625, 1.25, 2.5, 5, 10 mg/L or an acetone-spike control for 10d. Overt toxicity of RDX in fathead minnow occurred only at the highest exposure concentration resulting in 50% mortality. Conversely, Bayesian analysis of microarray data indicated significant changes in transcript expression in fathead minnow brain tissue at RDX concentrations as low as 0.625 mg/L. In total, 154 microarray targets representing 44 unique transcript identities were differentially expressed in RDX exposures, the majority of which were validated by RT-qPCR. Investigation of molecular pathways, gene ontology and individual gene functions indicated that RDX exposures affected metabolic processes involved in: oxygen transport, neurological function, calcium binding / signaling, energy metabolism, cell cycle / cell proliferation, oxidative stress and ubiquitination. In total, our study indicated that RDX exposure affected molecular processes critical to CNS function in fathead minnow.
2010-07-30 | GSE21153 | GEO
Project description:FSAT01021/OBJ01/28D:<br> TITLE: Development of methods for the assessment of the health effects from mixtures of food additives. SAP/S3 project code: 010.45073<br> TNO Voeding-TNO BIBRA project for UK Food Standard Agency<br> Objective No. 01: In vivo range finding studies in the rat with selected individual food additives.<br> <br> Rat study using 4 compounds, oral administration in diet (concentration given in ppm), for 28 days:<br> Butylated hydroxytoluene (BHT): 254 ppm; 762 ppm; 1523 ppm; 3046 ppm; 10154 ppm<br> Curcumin (CC): 254 ppm; 762 ppm; 2031 ppm; 4062 ppm; 10154 ppm<br> Propyl Gallate (PG): 203 ppm; 508 ppm; 1523 ppm; 3046 ppm; 6092 ppm<br> Thiabendazole (TB): 102 ppm; 254 ppm; 762 ppm; 2031 ppm; 5077 ppm<br> <br> <br> Within Objective No. 01: clinical chemistry, pathology, drug metabolizing enzymes are assessed as well.<br> <br> Within Objective No. 01: A smaller study in which rats were exposed for 3 days to two doses of BHT, CC, PG, TB was performed as well. Depending on the outcome of arrays performed within FSAT01021/OBJ01/28D, transcriptomics will be performed on these samples: the Experiment name then will be FSAT01021/OBJ01/3D<br> <br> for details: Rob Stierum , AVTO, Monday December 17th 2001
2008-06-09 | E-MEXP-116 | biostudies-arrayexpress