ABSTRACT: Transcriptional profiling of mouse liver after short-term in vivo exposure (up to 56 days) of C57BL-mice to carcinogenic and non-carcinogenic chemicals
Project description:Trancriptional profiling of rat liver after short-term (up tp 14 days) administration of carcinogenic and non-carcinogenic chemicals
Project description:Mycotoxin citrinin (CTN) is a secondary metabolite of fungi, becoming a contaminant widely found in foods, feeds, and fermented health supplements. CTN is known to disrupt microtubule and chromosome arrangement at high dose (50 - 150 μM), but the toxicological effect of CTN long-term exposure has not been clearly studied. To investigate the molecular mechanisms of genotoxic, clastogenic, and carcinogenic effects of CTN, RNA-seq was performed on HEK293 cells exposed to chronic 20 μM CTN treatment (3 days for short-term and 30 days for long-term). The transcriptomic profile may reveal some underlying mechanisms regarding chronic carcinogenic potential of CTN, providing information for risk assessment of CTN-contaminated grains and its commercial food products.
Project description:Febrile seizures are the most prevalent type of seizures among children up to 5 years of age (2-4% of Western-European children). Complex febrile seizures are associated with an increased risk to develop temporal lobe epilepsy. To investigate short- and long-term effects of experimental febrile seizures (eFS), we induced eFS in highly febrile convulsion-susceptible C57BL/6J mice at post-natal day 10 by exposure to hyperthermia (HT) and compared them to normotherm-exposed (NT) mice. We detected structural re-organization in the hippocampus 14 days after eFS. To identify molecular candidates, which entrain this structural re-organization, we investigated temporal changes in mRNA expression profiles eFS 1 hour to 56 days after eFS. We identified 931 regulated genes and profiled several candidates using in situ hybridization and histology at 3 and 14 days after eFS. This is the first study to report genome-wide transcriptome analysis after eFS in mice. We identify temporal regulation of multiple processes, such as stress-, immune- and inflammatory responses, glia activation, glutamate-glutamine cycle and myelination. Identification of the short- and long-term changes after eFS is important to elucidate the mechanisms contributing to epileptogenesis.
Project description:Febrile seizures are the most prevalent type of seizures among children up to 5 years of age (2-4% of Western-European children). Complex febrile seizures are associated with an increased risk to develop temporal lobe epilepsy. To investigate short- and long-term effects of experimental febrile seizures (eFS), we induced eFS in highly febrile convulsion-susceptible C57BL/6J mice at post-natal day 10 by exposure to hyperthermia (HT) and compared them to normotherm-exposed (NT) mice. We detected structural re-organization in the hippocampus 14 days after eFS. To identify molecular candidates, which entrain this structural re-organization, we investigated temporal changes in mRNA expression profiles eFS 1 hour to 56 days after eFS. We identified 931 regulated genes and profiled several candidates using in situ hybridization and histology at 3 and 14 days after eFS. This is the first study to report genome-wide transcriptome analysis after eFS in mice. We identify temporal regulation of multiple processes, such as stress-, immune- and inflammatory responses, glia activation, glutamate-glutamine cycle and myelination. Identification of the short- and long-term changes after eFS is important to elucidate the mechanisms contributing to epileptogenesis. Acute, short-, and long-term effects of prolonged febrile seizures on gene expression were investigated in whole hippocampal samples. Samples were taken from C57BL/6J animals one hour (HT n = 8, NT n = 8), three days (HT n = 6, NT n = 6), fourteen days (HT n = 6, NT n = 6), and fifty-six days (HT n = 6, NT n = 6) after HT. Two-channel oligonucleotide microarray analysis was performed with an NT and HT sample on the same chip, including a dye-swap (technical replicate). 3 failed hybridizations were omitted from further analysis.
Project description:The carcinogenic potential of chemicals is currently evaluated with rodent life-time bioassays, which are time consuming, and expensive with respect to cost, number of animals and amount of compound required. Since the results of these 2-year bioassays are not known until quite late during development of new chemical entities, and since the short-term test battery to test for genotoxicity, a characteristic of genotoxic carcinogens, is hampered by low specificity, the identification of early biomarkers for carcinogenicity would be a big step forward. Using gene expression profiles from the livers of rats treated up to 14 days with genotoxic and non-genotoxic carcinogens we previously identified characteristic gene expression profiles for these two groups of carcinogens. We have now added expression profiles from further hepatocarcinogens and from non-carcinogens the latter serving as control profiles. We used these profiles to extract biomarkers discriminating genotoxic from non-genotoxic carcinogens and to calculate classifiers based on the support vector machine (SVM) algorithm. These classifiers then predicted a set of independent validation compound profiles with up to 88% accuracy, depending on the marker gene set. We would like to present this study as proof of the concept that a classification of carcinogens based on short-term studies may be feasible.
Project description:Long-term exposure of Atlantic salmon to 19M-BM-0C resulted in cardiac gene and protein expression changes indicating that the unfolded protein response, vascularization, remodeling of connective tissue and altered innate immune responses were part of the cardiac acclimation or response to elevated temperature Heart tissue from Atlantic salmon (RNA poooled from N=3 fish per 3 replicate tanks) reared under normal (14 deg C) and elevated (19 deg C) temperatures were sampled after 21 (short-term) and 56 days (long-term acclimation), and gene expression changes between the elevated and the control temperature were assessed using microarray analysis.
Project description:Liver tumors in rodents are frequently induced by non-genotoxic carcinogens. These hepatocarcinogens generally activate hepatic nuclear receptors (e.g., CAR and PXR), resulting in a cascade of signals causing modifications in the expression of genes responsible for several processes involved in carcinogenesis. Evaluation of the carcinogenic potential of chemicals is a regulatory requirement but is time-consuming and expensive. Consequently, several short-term in vivo and in vitro approaches, using molecular tools, have been proposed as predictive models for non-genotoxic hepatocarcinogens. The objective of our study was to discriminate between chemicals that are either non-genotoxic hepatocarcinogens or merely hepatotoxicants and also between CAR and PXR modulators on the basis of their gene expression profiles. Thus, we treated rats for seven days with the hepatoxicants, diclofenac and diazepam, or with several CAR and PXR modulators, which were mainly hepatocarcinogens. Different hepatic gene expression profiles were obtained not only between the hepatotoxicants and the non-genotoxic hepatocarcinogens but also between the CAR activators phenobarbital, phenytoin and 1,1-bis-(4-chlorophenyl)-2,2-dichloroethene which were grouped together, and the two PXR activators pregnenolone 16α-carbonitrile and clotrimazole. Diethylstilbestrol had an expression profile that was quite distinct from the other PXR activators, suggesting that this compound is certainly not a classic PXR modulator. Moreover, some differences were observed between phenytoin (not considered as a hepatocarcinogen), and the other two CAR activators. Our data therefore indicate that discrimination is possible between hepatocarcinogens and hepatotoxicants, between CAR and PXR modulators and also between compounds within the same class of modulators using a short-term transcriptomic approach. CAR or PXR inducers were administered in suspension to rats (7 weeks old at start of treatment) by oral gavage at a daily dose for 7 consecutive days. Treatment-related changes in gene expression were determined in the liver using whole genome oligonucleotide microarrays.
Project description:Juvenile hormone (JH) and JH agonists have been reported to induce male offspring production in various daphnids including Daphnia magna. We have recently established a short-term in vivo screening method to detect chemicals having JH activity, induction of male offspring, using adult D. magna. Diofenolan has been developed to be a JH agonist in insects, but no male induction in daphniids has been studied. In this study, we found the male offspring induction by diofenolan with a short-term in vivo screening method, and the most potent male offspring production activity among JH analogs studied using the OECD TG211 Annex 7. Transcriptome analysis of diofenolan-exposed D. magna showed up-regulation of JH-responsive genes. These results clearly demonstrated that diofenolan has JH activities in D. magna using the short-term in vivo screening assay, OECD TG211 Annex 7 and microarray analysis.
Project description:Polycyclic aromatic hydrocarbons (PAHs) are a class of hundreds of structurally similar chemicals ubiquitously present in our environment. They are created during the incomplete combustion of organic materials, such as oil, wood, tobacco, and charbroiled meat. As such, human exposure to mixtures of PAHs can occur through consumption of PAH-containing foods and water, inhalation of polluted air, or dermal contact. Several PAHs have been classified as carcinogenic to humans or probably carcinogenic to humans by the International Agency for Research on Cancer. Chrysene is one such compound. In the present study, we sought to determine the dose-dependent changes in gene expression upon oral exposure to benz(a)anthracene in the lung, liver, and forestomach tissues. Adult male MutaTMMouse were exposed to three doses of chrysene or vehicle control (olive oil) for 28 days and sacrificed three days after the final exposure.