Identification of Exposure Biomarkers for Mutagenic Carcinogens in Complex Environmental Matrices
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ABSTRACT: We investigated an in vitro experimental exposure model of the MutaMouse flat epithelial (FE1) cells exposed to a complex mixture of carcinogenic PAHs known as coal tar (SRM 1597a) using an Agilent 22k, oligo mouse array platform. Keywords: Toxicology, biomarkers discovery, stress response, complex mixture of carcinogens, PAHs The FE1 cells were exposed to two different sub-toxic concentrations of coal tar (SRM 1597a): 1 mg/ml and 4 mg/ml in a serum free media. After 6h exposure, the cells were washed twice with PBS and re-incubated in fresh media without coal tar. After 4h and 8h incubation, the media were collected for proteomic experiment and the cells were collected from the petri dishes for RNA extraction.
Project description:We investigated the effects of thyroid hormone disruptions on gene expression in juvenile mice liver to develop a stronger understanding of the mechanisms by which thyroid disrupting chemicals impair development. Gene expression was examined by hybridization of hepatic RNA to Agilent mouse microarrays for hyper-, hypo-, hypo-replacement (hypo+) and euthyroid animals. Keywords: Toxicogenomics, biomarkers of thyroid disruptors Hypothyroidism was induced from post natal day (PND) 13 to 15 by adding model thyroid toxicants methimazole and sodium perchlorate to drinking water of pregnant females. Hyperthyroidism was induced by intraperitoneal injections (i.p.) of THs at PND 15, 4 hours before decapitation and tissue collection. For the hypothyroid/replacement group; dams were provided with drinking water for 3 days (PND 13 to 15), containing a mixture of methimazole/sodium perchlorate. Pups then received intraperitoneal injections of thyoid hormones on PND 15, 4 hours before decapitation and tissue collection.
Project description:Benzo[a]pyrene (BaP) is a very extensively studied prototypical polycyclic aromatic hydrocarbons (PAHs). Previous work in our laboratory showed no changes of microRNA (miRNA) expression in liver following a 3 days exposure to BaP, suggesting a lack of miRNA transcriptional responses to aryl hydrocarbon receptor agonists and/or DNA damage. Here, we studied 25-week old male MutaTM Mouse exposed to 25, 50, and 75 mg/kg/day BaP by oral gavage for 28 consecutive days. MAANOVA identified 110 differentially expressed genes (adjusted p < 0.05) with fold change greater than 1.5. The genes most affected included those involved in xenobiotic metabolism, phase II metabolizing enzymes, as well as the downstream targets of p53. Pathway specific RT-PCR was used to confirm the p53 response. A single significant increase in miRNA expression was identified (mir-34a and validated using the Qiagen miScript PCR system). This miRNA is known to be transcriptionally activated by p53. Ingestion of BaP leads to widespread changes in gene expression in mouse liver, with enrichment of genes involved in cell cycle arrest, DNA damage response, and apoptosis via the p53 pathway. In contrast, miRNA expression was relatively unaffected. Only miR-34a was significantly up-regulated, and may therefore play a critical role in the post-transcriptional regulation of p53 and/or its downstream targets. Keywords: Agilent mouse 4 x 44 oligonucleotide microarrays were used to assess global gene expression in response to 25, 50, and 75 mg/kg BaP treatment Individual total RNA (200 ng) from 5 mice per treatment group (control, 24mg/kg, 50mg/kg, and 75mg/kg) and universal reference total RNA (Stratagene, Mississauga, ON, Canada) was used to synthesize double stranded cDNA.
Project description:Adult male mice were exposed to 150 mg/kg benzo(a)pyrene (BaP) or solvent for 3 days and sampled 4 or 24 hours after the last dose. mRNA expression levels in adult mouse liver were measured using Agilent arrays. We found widespread changes in mRNA in pathways consistent with known response (xenobiotic metabolism, glutathione). We also found that BaP caused changes in the circadian rhythm pathway. We measured miRNA changes in the same samples and found no evidence for any change in transcription of miRNA as a result of the exposure. Keywords: Toxicology, time course Adult male B6C3F1 mice were exposed to a daily dose of corn oil (vehicle control group) or 150 mg/kg BaP (treatment group) for 3 days (n=5 per group). Mice were sacrificed at 4 h or 24 h following the last dose and liver lobes were extracted and flash frozen. RNA was extracted from median liver lobes and hybridized to the Agilent 4 x 44K mouse DNA arrays using a randomized block design.
Project description:We examined the effect of acetaminophen (APAP) on the transcriptional response induced by interferon-β (IFN-β). Transcript levels from total RNA isolated rom murine livers were determined using G4121B whole genome arrays. Keywords: Pharmakinetics, drug treatment 6-8 week male CD-1 mice were administered vehicle alone, APAP, IFN-β or IFN-β + APAP (n=5 per treatment per time point 40 animals total) and were euthanized at 1.5 or 4 hours post-treatment. Agilent 22k whole genome arrays were used to measure changes in mRNA transcripts in the liver mRNA. Stratatagene Universal Mouse RNA was used as a reference.
Project description:In the present study we investigate the effect of maternal pulmonary exposure to titanium dioxide (UV-Titan designed for use in the paint and lacquer industry) on prenatally exposed offspring. Time-mated mice (C57BL/6BomTac) were exposed by inhalation for 1 h/day to 42 mg UV-titan/m3 aerosolized powder or filtered air during gestation days (GD) 8-18. We evaluated levels of DNA strand breaks using the comet assay in bronchioalveolar lavage (BAL) cells and liver cells of the time-mated mice, and in liver cells of the offspring. In parallel, we analyzed changes in gene expression in the liver tissue of offspring using DNA microarrays. We demonstrate that UV-Titan did not induce DNA strand breaks in the time-mated mice or their offspring. Transcriptional profiling of newborn liver tissue revealed changes in the expression of genes related to the retinoic acid (RA) signalling pathway in the females, while gene expression in male offspring was relatively unaffected by exposure. Time-mated, nulliparous mice (C57BL/6BomTac, Taconic Europe, Ejby, Denmark) were exposed to filtered clean air or approximately 42 mg/m3 UV-Titan on GD 8M-bM-^@M-^S18 for 1 hr/day by a whole-body exposure.Delivery was expected on GD 20, and designated postnatal day (PND) 0. On PND 2, one offspring (M-bM-^@M-^\newbornM-bM-^@M-^]) per litter was killed by decapitation, to yield litters with at least 5 offspring per exposure group. The newborn offspring were collected two days after birth. On PND 23-24 (M-bM-^@M-^\at weaningM-bM-^@M-^]) one male and one female per litter were killed. Organs were dissected, weighed, placed in NUNC cryotubes, snap frozen in liquid N2 and stored at -80M-BM-0C until analysis. Exposed dams were killed on PND 24-25 (26-27 days after last exposure). DNA strad break detection was carried out in bronchoalveolar lavage fluid in dams by COMET assay. Total RNA was extracted from offspring livers and gene expression profiling was carried out on whole liver tissues from offspring. 9 UV-Titan treated and 7 controls mice consisting of 8 males and 8 females mRNA, hepatic, developmental, Toxicogenomics, nano-titanium dioxide
Project description:This SuperSeries is composed of the following subset Series: GSE24907: Lack of hepatic response of microRNA in mice following chronic benzo(a)pyrene exposure (gene expression) GSE24909: Lack of hepatic response of microRNA in mice following chronic benzo(a)pyrene exposure (miRNA) Refer to individual Series
Project description:MicroRNAs (miRNAs) are extensively in diverse biological processes. However, very little is known about the role of miRNAs in mediating thyroid hormones (TH) action. Maintenance of appropriate TH levels is known to be critically important for development, differentiation and maintenance of metabolic balance in mammals. We induced transient hypothyroidism in juvenile mice by short term exposure to methimazole and perchlorate from post natal day (PND) 12 to 15. The expression of miRNAs in the liver was analyzed with the Taqman Low Density Array (containing up to 600 rodent microRNAs). We found the expression of 40 miRNAs was significantly altered in the liver of hypothyroid mice compared to euthyroid controls. Among the miRNAs, miR-1/206/133 exhibited a massive increase in expression (50 – 500 folds). To further explore TH effect on miR-1/206/133, we treated mouse hepatocyte AML 12 cells with 10 nm T3 for 1 hr and 24 hrs. TH treatment induced the down-regulation of miR-1/206/133b at both time points, reaching statistical significance at 24 hrs. To identify the genes targeted by these miRNAs, DNA microarrays were used to examine hepatic mRNA levels in the hypothyroid mouse model alongside controls. We found transcripts from 92 known genes were significantly altered in hypothyroid mice. Web-based target predication softwares (TargetScan and Microcosm) identified 14 of these transcripts as targets of miR-1/106/133. The vast majority of these mRNA targets were significantly down-regulated in hypothyroid mice, corresponding well with the up-regulation of miR-1/206/133 in hypothyroid mouse liver. The results suggest that TH regulation of these genes may occur secondarily via the reduced repression consequent to TH-induced down-regulation of miR-1/206/133. These studies provide novel insight into the role of miRNAs in mediating TH regulation of gene expression. Agilent two-color microarray were used to perform gene expression profile in euthyroid and hypothyroid male mouse livers, 5 biological replicates. TLDA (Taqman microRNA Array) was used to explore the miRNA expression profile in euthyroid and hypothyroid male mouse livers, 4 biological replicates.
Project description:Acute phase reactants serum amyloid A-1, 3 and micro RNA-135b, -449a, and -1 are induced in lungs of mice exposed to subtoxic doses of nano-titanium dioxide particles by inhalation In the present study we investigate pulmonary mRNA and miRNA profiles of mice exposed to subtoxic dose of nano-titanium dioxide particles by inhalation. We show dramatic induction of acute phase reactants, chemoattractants, immune and host defence related genes. We also demonstrate for the first time changes in miRNA profiles in the lungs in response to nanoTiO2. Keywords: Toxicology, disease state analysis, biomarkers of health effects Female C57BL/6 mice were exposed to 40 mg nanoTiO2/m3 for one hour/day for 11 consecutive days and were sacrificed 5 days following the last exposure. Left lung lobes and liver were removed and flash frozen. Total RNA was isolated from a small random part of the frozen lung and liver and was hybridized against universal mouse reference RNA to Agilent Oligo DNA microarrays (Agilent Technologies) containing 44,000 transcripts. Microarrays were normalized using a global LOWESS approach and analyzed by MAANOVA 2.0 and SAM. Microarray results were validated by real time RT-PCR. Impact of alteration in expression of select genes was further validated by analysing their total protein levels in lung tissue homogenates.
Project description:Polycyclic aromatic hydrocarbons (PAHs) are widely distributed, carcinogenic environmental contaminants produced as a consequence of the incomplete combustion of fossil fuels. Benzo[a]pyrene (BaP) is a very extensively studied prototypical PAH. We recently reported a complete lack of change in microRNA (miRNA) expression in adult mouse liver following oral gavage with BaP despite a robust transcriptome response. We hypothesized that hepatic miRNAs may not be highly responsive to the treatment. Here, we analyse the pulmonary mRNA and miRNA response to BaP in the same mice. Adult male B6C3F1 mice were exposed to 5, 50, 150 and 300 mg/kg BaP by oral gavage for three consecutive days and sacrificed 4 or 24 hours after the last exposure. Serum clinical chemistry and DNA adduct levels in whole lung and liver tissues were analysed at both the time points for all the doses. Acute exposure to BaP resulted in modest decreases in serum inorganic phosphorous, calcium, glucose, alkaline phosphatase and lactate dehydrogenase in animals treated with 300 mg/kg BaP. 32P postlabeling of DNA revealed similar increases in BaP-DNA adducts in both lungs and livers of exposed mice in a dose dependent manner at the 4 hour time point. Using DNA microarrays, pulmonary mRNA and miRNA expression was analysed 4 hours after the final exposure. Over 1,000 genes were statistically differentially expressed (fold change > 1.5 and p < 0.05), encompassing numerous pathways including: oxidative stress, xenobiotic metabolism, cell proliferation, cell cycle, B and T-cell receptor signalling and primary immunodeficiency signalling pathways. Analysis of miRNA profiles revealed downregulation of miR-150, miR-142-5p, 142-3p and upregulation of miR-34c and miR-29b. These miRNAs are involved in various biological processes including immune response, cell proliferation and cell cycle, which are also the main pathways affected at the gene expression level. As BaP exposure does not result in hepatocarcinogenicity, but does cause lung cancer, these miRNAs may play an important role in the outcome of the exposure and be more predictive of carcinogenesis. Keywords: mRNA, miRNA, Pulmonary, non-target tissue, Toxicogenomics, Benzoapyrene Adult male B6C3F1 mice were exposed to 5, 50, 150 and 300 mg/kg BaP by oral gavage for three consecutive days and sacrificed 4 or 24 hours after the last exposure. Serum clinical chemistry and DNA adduct levels in whole lung and liver tissues were analysed at both the time points for all the doses. Using DNA microarrays, pulmonary mRNA and miRNA expression was analysed 4 hours after the final exposure. This submission only contains the 4hr time point, at control, 150mg/kg and 300mg/kg (except for the liver study where only the control and 300mg/kg samples were used).
Project description:We investigated an in vitro experimental exposure model of the MutaMouse flat epithelial (FE1) cells exposed to a complex mixture of carcinogenic PAHs known as coal tar (SRM 1597a) using an Agilent 22k, oligo mouse array platform. Keywords: Toxicology, biomarkers discovery, stress response, complex mixture of carcinogens, PAHs