2,3,7,8-TCDD (TCDD) is a reproductive toxicant and endocrine disruptor in nearly all vertebrates, yet the mechanisms by which TCDD induces these reproductive alterations have not been fully characterized. Fish are among the most sensitive vertebrates to the toxic effects of TCDD, and even subtle physiologic changes induced by TCDD can impair reproduction. Previously, we have shown that chronic, sub-lethal exposure to TCDD decreased reproductive capacity, reduced serum estradiol and vitellogenin concentrations, and altered follicular development. Here we investigate the transcriptional changes in zebrafish ovary as they relate to observed attenuated estradiol concentrations and ovarian development. We used quantitative RT-PCR to assess TCDDs effects on the expression of several candidate genes important in the regulation of follicular development and steroidogenesis. Additionally, global changes in gene expression in the ovary caused by TCDD exposure were identified using Affymetrix Gene Chip Analysis. Our data suggest that TCDD may inhibit follicle maturation via attenuated gonadotropin responsiveness and/or depressed estradiol biosynthesis. Additionally, genes involved in glucose and lipid metabolism, regulation of transcription, and immune function were dysregulated by at least 2-fold suggesting that TCDD alters various integrated networks of signaling pathways. Approximately 89% of dysregulated transcripts contain putative AHR response elements (AHRE) within 5kb upstream of the predicted transcriptional start site suggesting ovarian toxicity is AHRE driven. Furthermore, approximately 49% of dysregulated transcripts contain putative estrogen response elements (ERE) suggesting that dysregulation of estrogen-responsive genes may also contribute to TCDD-induced attenuated follicular development. Patterns in gene expression were correlated with putative EREs and AHREs, and suggest that impacts on the regulation of transcription may play a large role in TCDDs ovarian toxicity. Taken together, these data illustrate the complexity of TCDDs ovarian toxicity.
Molecular targets of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) within the zebrafish ovary: insights into TCDD-induced endocrine disruption and reproductive toxicity.
Sex, Specimen part
View SamplesThe purpose of this study was to characterize the transcriptional effects induced by subcutaneous IFN-beta-1b treatment (Betaferon, 250 g every other day) in patients with relapsing-remitting form of multiple sclerosis (MS).
Long-term genome-wide blood RNA expression profiles yield novel molecular response candidates for IFN-beta-1b treatment in relapsing remitting MS.
Sex
View SamplesThis SuperSeries is composed of the SubSeries listed below.
No associated publication
Specimen part
View SamplesGene expression profile comparison from fibroblasts of Huntington individuals and normal ones
Gene expression profile in fibroblasts of Huntington's disease patients and controls.
Sex, Age, Specimen part, Disease
View SamplesComparison of the differential expression mRNA profiles from the brain cortex of hypoxia and normaixa rats by silica microarray chip
No associated publication
Specimen part
View SamplesBone mineral density and structure candidate gene analysis in alcohol-non-preferring (NP), alcohol-preferring (P), congenic NP (NP.P) and congenic P (P.NP) rats
Identification of genes influencing skeletal phenotypes in congenic P/NP rats.
No sample metadata fields
View SamplesFemoral neck bone mineral density and structure candidate gene analysis in Fischer 344 (F344) and Lewis (LEW) rats
Genomic expression analysis of rat chromosome 4 for skeletal traits at femoral neck.
No sample metadata fields
View SamplesGene expression was measured using microarrays in 8 hour postfertilization embryos, comparing control versus ethanol-treated (2 to 8 hours postfertilization) embryos. This experiment was performed to determine the gene expression changes that occur in response to ethanol treatment as a model of fetal alcohol spectrum disorder.
Ethanol exposure disrupts extraembryonic microtubule cytoskeleton and embryonic blastomere cell adhesion, producing epiboly and gastrulation defects.
Age, Specimen part, Treatment
View SamplesEthanol exposure during prenatal development causes fetal alcohol spectrum disorder (FASD), the most frequent preventable birth defect and neurodevelopmental disability syndrome. The molecular targets of ethanol toxicity during development are poorly understood. Developmental stages surrounding gastrulation are very sensitive to ethanol exposure. To understand the effects of ethanol on early transcripts during embryogenesis, we treated zebrafish embryos with ethanol during pre-gastrulation period and examined the transcripts by Affymetrix GeneChip microarray before gastrulation. We identified 521 significantly dysregulated genes, including 61 transcription factors in ethanol-exposed embryos. Sox2, the key regulator of pluripotency and early development was significantly reduced. Functional annotation analysis showed enrichment in transcription regulation, embryonic axes patterning, and signaling pathways, including Wnt, Notch and retinoic acid. We identified all potential genomic targets of 25 dysregulated transcription factors and compared their interactions with the ethanol-dysregulated genes. This analysis predicted that Sox2 targeted a large number of ethanol-dysregulated genes. A gene regulatory network analysis showed that many of the dysregulated genes are targeted by multiple transcription factors. Injection of sox2 mRNA partially rescued ethanol-induced gene expression, epiboly and gastrulation defects. Additional studies of this ethanol dysregulated network may identify therapeutic targets that coordinately regulate early development.
Embryonic ethanol exposure alters expression of sox2 and other early transcripts in zebrafish, producing gastrulation defects.
Treatment
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Integrated analysis of global mRNA and protein expression data in HEK293 cells overexpressing PRL-1.
Cell line
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