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E-GEOD-61039 - Transcriptional Profiling of rat hypothalamic response to TCDD

Status
Released on 23 December 2014, last updated on 2 January 2015
Organism
Rattus norvegicus
Samples (16)
Array (1)
Protocols (7)
Description
In many mammals, halogenated aromatic hydrocarbon (HAH) exposure causes wasting syndrome, defined as lethal weight loss as a result of severe and persistent hypophagia. The most potent HAH in causing wasting is 2,3,7,8-tetrachlorodibenzo-ρ-dioxin (TCDD), which exerts its toxic effects through the aryl hydrocarbon receptor (AHR) – a transcription factor. Because TCDD toxicity is thought to predominantly arise from dysregulation of AHR-transcribed genes, we hypothesized that wasting syndrome is due to TCDD-induced dysregulation of genes involved in regulation of food-intake. We therefore focused on the hypothalamus, as it is the regulatory center of food-intake and energy balance in the central nervous system. We profiled mRNA abundance in hypothalamic tissue from two rat strains with widely differing sensitivities to wasting syndrome: TCDD-sensitive Long-Evans rats and TCDD-resistant Han/Wistar rats, 23 hours after exposure to TCDD (100 μg/kg) or corn oil vehicle. We found that TCDD exposure caused minimal transcriptional dysregulation effects in the hypothalamus, with only 6 genes changed in Long-Evans rats and 15 genes in Han/Wistar rats. Two of the most dysregulated genes were Cyp1a1 and Nqo1, which are induced by TCDD across a wide range of tissues and are considered sensitive markers of TCDD exposure. The minimal response of the hypothalamic transcriptome to a lethal dose of TCDD at an early time-point suggests that the hypothalamus is not the predominant site of initial events leading to hypophagia and associated wasting. TCDD may affect feeding behaviour via events upstream or downstream of the hypothalamus, and further work is required to evaluate this at the level of individual hypothalamic nuclei and subregions. Two strains, each with drug-treated vs vehicle-control
Experiment type
transcription profiling by array 
Contacts
Stephenie Prokopec <stephenie.prokopec@oicr.on.ca>, Allan B Okey, Ivy D Moffat, Jere Lindén, Kathleen E Houlahan, Paul C Boutros, Raimo Pohjanvirta, Sanna Lensu, Stephenie D Prokopec
Citation
MIAME
PlatformsProtocolsVariablesProcessedRaw
Files
Investigation descriptionE-GEOD-61039.idf.txt
Sample and data relationshipE-GEOD-61039.sdrf.txt
Raw data (1)E-GEOD-61039.raw.1.zip
Processed data (1)E-GEOD-61039.processed.1.zip
Additional data (1)E-GEOD-61039.additional.1.zip
Array designA-GEOD-19144.adf.txt
Links