Liver gene transcripts patterns were used to characterize toxicity from exposure to polybrominated diphenyl ethers (PBDEs), flame retardant components. In this study, Wistar Han dams were exposed by gavage to the PBDE mixture (DE71) starting at gestation day 6 (GD 6) and continuing to weaning on postnatal day 21 (PND 21). Offspring from the dams began PBDE direct dosing on PND 12 and were dosed daily through PND 21. After weaning, they were dosed 5 days per week for another 13 weeks. Liver samples were collected at PND 22 and week 13 for liver gene expression analysis and interrogated with the Affymetrix Rat Genome 230 2.0 Array.
Characterization of polybrominated diphenyl ether toxicity in Wistar Han rats and use of liver microarray data for predicting disease susceptibilities.
Sex, Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Sleep is not just for the brain: transcriptional responses to sleep in peripheral tissues.
Specimen part, Treatment, Time
View SamplesMolecular profiles in sleep and sleep deprivation in peripheral tissues using microarrays
Sleep is not just for the brain: transcriptional responses to sleep in peripheral tissues.
Specimen part, Treatment, Time
View SamplesMolecular profiles in sleep and sleep deprivation in peripheral tissues using microarrays
Sleep is not just for the brain: transcriptional responses to sleep in peripheral tissues.
Specimen part, Treatment, Time
View SamplesRosiglitazone (Rosi), a member of the thiazolidinedione class of drugs used to treat type 2 diabetes, activates the adipocyte-specific transcription factor peroxisome proliferator-activated receptor gamma (PPARg). This activation causes bone loss in animals and humans, at least in part due to suppression of osteoblast differentiation from marrow mesenchymal stem cells (MSC). In order to identify mechanisms by which PPARg2 suppresses osteoblastogenesis and promotes adipogenesis in MSC, we have analyzed the PPARg2 transcriptome in response to Rosi. A total of 4,252 transcriptional changes resulted when Rosi (1 uM) was applied to the U-33 marrow stromal cell line, stably transfected with PPARg2 (U-33/g2), as compared to non-induced U-33/g2 cells. Differences between U-33/g2 and U-33 cells stably transfected with empty vector (U-33/c) comprised 7,928 transcriptional changes, independent of Rosi. Cell type-, time- and treatment-specific gene clustering uncovered distinct patterns of PPARg2 transcriptional control of MSC lineage commitment. The earliest changes accompanying Rosi activation of PPARg2 included adjustments in morphogenesis, Wnt signaling, and immune responses, as well as sustained induction of lipid metabolism. Expression signatures influenced by longer exposure to Rosi provided evidence for distinct mechanisms governing the repression of osteogenesis and stimulation of adipogenesis. Our results suggest interactions that could lead to the identification of a master regulatory scheme controlling osteoblast differentiation.
PPARgamma2 nuclear receptor controls multiple regulatory pathways of osteoblast differentiation from marrow mesenchymal stem cells.
Compound, Time
View SamplesTo gain insight into the dynamic molecular processes that are altered during prolonged wakefulness and during sleep. We performed an RNA expression profiling study examining temporal changes in the brain of Drosophila in relationship to the duration of prior sleep or wakefulness. Our experimental design allowed us to determine whether genes identified as differentially regulated between sleep and wakefulness were up- or down-regulated in these states.
Multiple mechanisms limit the duration of wakefulness in Drosophila brain.
Sex, Age, Specimen part
View SamplesA recent two-year NTP cancer bioassay showed a marked increase in the incidence of malignant mesothelioma arising from the tunica vaginalis in male Fischer 344/N rats exposed to Vinylidene chloride (VDC). Aged male F344/N rats are prone to developing spontaneous peritoneal mesotheliomas, which also arise predominantly from the tunica vaginalis of the testes. A definitive mechanism for the observed increased incidence in VDC-exposed rats is unknown. Investigation of the molecular alterations that occur in mesotheliomas from vehicle control and VDC-exposed rats may provide insight into their pathogenesis, as well enable a better understanding regarding the mechanisms underlying chemically induced mesothelioma in rodents. Mesothelial cell function represents a complex interplay of pathways related to host defense mechanisms and maintenance of cellular homeostasis. Global gene expression profiles of spontaneous mesotheliomas from vehicle control male F344/N rats from various two-year National Toxicology Program carcinogenicity bioassays were compared to mesotheliomas from VDC-exposed rats to characterize the molecular features that are present in mesotheliomas from VDC-exposed animals, and to elucidate tumor-specific gene expression profiles. The resulting gene expression pattern showed that mesotheliomas from VDC-exposed animals are genomically very different from spontaneous tumors; while both tumor types are characterized by alterations in gene expression associated with carcinogenic pathways (oncogenes, tumor suppressor genes, growth factors, etc.), mesotheliomas from VDC-exposed animals are associated with increased dysreguation of immune pathways and inflammatory mediators. Alterations in these pathways may suggest a pro-inflammatory and immune dysfunction signature as one mechanism in the observed increased incidence of these tumors in VDC-exposed animals.
Spontaneous mesotheliomas in F344/N rats are characterized by dysregulation of cellular growth and immune function pathways.
Disease
View SamplesTo identify nasal cavity transcripts differentially expressed due to treatment with N, N-dimethyl-p-toluidine (DMPT), we collected RNA during the from male F344/N rats exposed to 120 mg/kg DMPT, 5 days after DMPT exposure for animals 5-6 weeks of age. These samples were interrogated with the Affymetrix Rat Genome 230 2.0 GeneChip Array.
Molecular Changes in the Nasal Cavity after N, N-dimethyl-p-toluidine Exposure.
Sex
View SamplesThese studies address temporal changes in gene expression during spontaneous sleep and extended wakefulness in the mouse cerebral cortex, a neuronal target for processes that control sleep; and the hypothalamus, an important site of sleep regulatory processes. We determined these changes by comparing expression in sleeping animals sacrificed at different times during the lights on period, to that in animals sleep deprived and sacrificed at the same diurnal time.
Macromolecule biosynthesis: a key function of sleep.
Sex, Age, Specimen part
View SamplesTo identify liver transcripts differentially expressed due to treatment with N, N-dimethyl-p-toluidine (DMPT) and p-toluidine, we collected RNA during the from male F344/N rats exposed to 0, 1, 6, 20, 60 or 120 mg/kg DMPT (or p-toluidine), 5 days after exposure for animals 5-6 weeks of age. These samples were interrogated with the Affymetrix Rat Genome 230 2.0 GeneChip Array.
Hepatic transcriptomic alterations for N,N-dimethyl-p-toluidine (DMPT) and p-toluidine after 5-day exposure in rats.
Specimen part
View Samples