Transcriptomics of the Fetal Hypothalamic Response to Brachiocephalic Occusion and Estradiol Treatment
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ABSTRACT:
ORGANISM(S): Ovis aries
SUBMITTER: Charles Wood
PROVIDER: E-GEOD-52888 | biostudies-arrayexpress |
REPOSITORIES: biostudies-arrayexpress
Similar Datasets
Project description:Estradiol (E2) is a well-known modulator of fetal neuroendocrine activity, and has been proposed as a critical endocrine signal readying the fetus for birth and postnatal life. To investigate the modulatory role of E2 on fetal stress responsiveness and the response of the fetal brain to asphyxic stress, we subjected chronically catheterized fetal sheep to a transient (10 min) brachiocephalic occlusion or sham occlusion. Half of the fetuses received subcutaneous pellets that released E2 (5 days@~250 μg/day, increasing plasma E2 from 62±6 to 102±12 pg/mL). Hypothalamic mRNA was analyzed using the Agilent 8x15k ovine array (019921), processed and annotated as previously reported by our laboratory. Analysis of the data by ANOVA revealed that E2 differentially regulated (DR) 561 genes, and BCO DR 894 genes compared to control and estradiol+BCO DR 1153 genes compared to BCO alone (all p<0.05). E2 upregulated epigenetic pathways and downregulated local steroid biosynthesis, but did not significantly involve genes known to directly respond to the estrogen receptor (ie., contain ERE sequences). BCO upregulated kinase pathways as well as genes associated with lymphocyte infiltration into the brain, and downregulated neuropeptide synthesis. E2 upregulated immune- and apopotosis- related pathways after BCO, and reduced kinase and epigenetic pathway responses to the BCO. We conclude that array results are consistent with the results of more limited hypotheses previously published from these experiments.
2014-07-01 | GSE52888 | GEO
Project description:In the fetal sheep during late gestation sulfoconjugated estrogens in plasma reach a concentration 40-100 times greater than unconjugated estrogens. The objective of the present study was to determine the genomics of estradiol-3-sulfate (E2S) action in the fetal brain. The hypothesis was that E2S stimulates genes involved in the neuroendocrine pathways in the hypothalamus that direct or facilitate fetal development at the end of gestation. Four sets of chronically-catheterized ovine twin fetuses were studied (gestational age: 120-127 days gestation) with one infused with E2S intracerebroventricularly (1 mg/day) and the other remained untreated (control). After euthanasia, mRNA samples were extracted from the 8 hypothalami, corresponding to the four treatment and four control fetuses. Microarray analysis was performed following the Agilent protocol for 1-color 8x15 microarrays, designed for Ovis aries. A total of 4 sets of chronically-catheterized ovine twin fetuses were studied with one infused with estradiol-3-sulfate intracerebroventricularly (1 mg/day) for 7-12 days, using an osmotic mini-pump implanted in the fetus, and the other served as an untreated control. The gestational age at the time of surgery was 120-127 days of gestation. Twin fetuses were randomly assigned to the two groups at the time of surgery. After 7-12 days of infusion, twin fetuses of known gestational age (130 to 134 days) were euthanized and mRNA samples were extracted from the 8 hypothalami, corresponding to the four treatment and four control fetuses.
2011-08-02 | E-GEOD-31184 | biostudies-arrayexpress
Project description:In the fetal sheep during late gestation sulfoconjugated estrogens in plasma reach a concentration 40-100 times greater than unconjugated estrogens. The objective of the present study was to determine the genomics of estradiol-3-sulfate (E2S) action in the fetal brain. The hypothesis was that E2S stimulates genes involved in the neuroendocrine pathways in the hypothalamus that direct or facilitate fetal development at the end of gestation. Four sets of chronically-catheterized ovine twin fetuses were studied (gestational age: 120-127 days gestation) with one infused with E2S intracerebroventricularly (1 mg/day) and the other remained untreated (control). After euthanasia, mRNA samples were extracted from the 8 hypothalami, corresponding to the four treatment and four control fetuses. Microarray analysis was performed following the Agilent protocol for 1-color 8x15 microarrays, designed for Ovis aries.
2011-08-03 | GSE31184 | GEO
Project description:Fetuses respond to transient hypoxia (a common stressor in utero) with cellular responses that are appropriate for promoting survival of the fetus. The present experiment was performed to identify the acute genomic responses of the fetal hypothalamus to transient hypoxia. Three fetal sheep were exposed to 30 min of hypoxia and hypothalamic mRNA extracted from samples collected 30 min after return to normoxia. These samples were compared to those from 4 normoxic control fetuses using the Agilent 019921 ovine array. Differentially-regulated genes were analyzed by network analysis and by gene ontology analysis, identifying statistically significant overrepresentation of biological processes. Real-time PCR of selected genes supported the validity of the array data. Hypoxia induced increased expression of genes involved in response to oxygen stimulus, RNA splicing, anti-apoptosis, vascular smooth muscle proliferation, and positive regulation of Notch receptor target. Downregulated genes were involved in metabolism, antigen receptor-mediated immunity, macromolecular complex assembly, S-phase, translation elongation, RNA splicing, protein transport, and post-transcriptional regulation. We conclude that these results emphasize that the cellular response to hypoxia involves reduced metabolism, the involvement of the fetal immune system, and the importance of glucocorticoid signaling. 3 Ventilatory Hypoxia (VH) and 4 Control (con) fetuses. All fetuses were chronically catheterized and in late gestation. Hypoxia produced by low PO2 in maternal inspired gas for 30 min, followed by normoxia recovery for 30 min. Control fetuses maintained at normoxia for 30 min, followed by another 30 min of normoxia. Hypothalami collected for mRNA at end of normoxic recovery period.
2014-01-16 | E-GEOD-43371 | biostudies-arrayexpress
Project description:Triclosan (TCS), an antibacterial compound commonly added to personal care products, could be an endocrine disruptor at low doses. Although TCS has been shown to alter fetal physiology, its effects in the developing fetal brain are unknown. The objective of this study was to use transcriptomics and systems analysis to determine significantly altered biological processes in the late gestation ovine fetal hypothalamus after direct or indirect exposure to low doses of TCS. We found that short-term infusion of TCS induces vigorous changes in the fetal hypothalamic transcriptomics, which are mainly related to food intake pathways and metabolism. For direct TCS exposure, chronically catheterized late gestation fetal sheep were infused with vehicle (n=4) or TCS (250 μg/day; n=4) iv. For indirect TCS exposure, TCS (100 μg/kg/day; n=3) or vehicle (n=3) was infused into the maternal circulation. Fetal hypothalami were collected after 2 days of infusion, and gene expression was measured using Agilent 15k ovine microarrays.
2016-02-29 | E-GEOD-69275 | biostudies-arrayexpress
Project description:Transient hypoxia in pregnancy stimulates a physiological reflex response that redistributes blood flow and defends oxygen delivery to the fetal brain. The chemoreceptor reflex that is responsible for this physiological response is dependent on glutamatergic neurotransmission which, in times of vigorous activity, could produce cell death secondary to calcium uptake. We designed the present experiment to test the hypotheses that transient hypoxia produces damage of the cerebral cortex and that ketamine, an antagonist of NMDA receptors, reduces the damage. Late-gestation, chronically catheterized fetal sheep were subjected to a 30 min period of ventilatory hypoxia that decreased fetal PaO2 from 17±1 to 10±1 mm Hg, or normoxia (PaO2 17±1 mm Hg), with or without pretreatment (10 min before hypoxia/normoxia) with ketamine (3 mg/kg, iv). One day (24 h) after hypoxia/normoxia, fetal cerebral cortex was removed and mRNA extracted for transcriptomics and systems biology analysis. Hypoxia stimulated a transcriptomics response consistent with a reduction in cellular metabolism and an increase in inflammation. Ketamine pretreatment reduced both of these responses. The inflammation response modeled with transcriptomic system biology was validated by immunohistochemistry and showed increased abundance of microglia/macrophages after hypoxia in the cerebral cortical tissue that ketamine significantly reduced. We conclude that transient hypoxia produces inflammation of the fetal cerebral cortex and that ketamine, in a standard clinical dose, reduces the inflammation response. 4 groups: hypoxia, hypoxia plus ketamine, normoxia, normoxia plus ketamine. Hypoxia produced by low PO2 in maternal inspired gas for 30 min, followed by normoxia recovery for 23.5 hours. Control fetuses maintained at normoxia for 30 min, followed by another 23.5 h of normoxia. Fetal frontal cerebral cortex collected for mRNA at end of 23.5 h recovery period.
2016-04-06 | E-GEOD-76110 | biostudies-arrayexpress
Project description:Acute fetal hypoxia is a form of fetal stress that stimulates renal vasoconstriction and ischemia as a consequence of the physiological redistribution of combined ventricular output. We have demonstrated that hypoxia in late ovine gestation induces inflammation in the brain that is ameliorated by treatment with ketamine. We hypothesized that the fetal kidney would also respond to hypoxia with an increase in the expression of inflammatory genes, and that ketamine (an N-Methyl-D-aspartate receptor antagonist) would reduce or block this response. Enriched biological processes for the 427 upregulated genes were immune and inflammatory responses and for the 946 down-regulated genes were metabolic processes. Ketamine countered the effects of hypoxia on upregulated immune/inflammatory responses as well as the down-regulated metabolic responses. We conclude that our transcriptomics modeling predicts that hypoxia activates inflammatory pathways and reduces metabolism in the fetal kidney cortex, and ketamine blocks or ameliorates this response. The results suggest that ketamine may have therapeutic potential for protection from ischemic renal damage. At the time of surgery, fetuses were randomly assigned to one of the four groups (n=3-4/group): normoxic control, normoxia+ketamine, hypoxic control, and hypoxia+ketamine. Hypoxia was induced for 30 min in chronically catheterized fetal sheep (125±3 d; term=145-147d), with or without ketamine (3 mg/kg) administered intravenously to the fetus 10 min prior to hypoxia. Fetuses were euthanized 24 hours after the onset of hypoxia, and the kidney cortex were collected for RNA extraction and gene array studies. Gene expression was analyzed using ovine Agilent 15.5 k array and validated with qPCR. Significant differences in gene expression between groups were determined with t-statistics using the limma package for R (Pâ¤0.05).
2016-09-01 | E-GEOD-66920 | biostudies-arrayexpress
Project description:The physiological response to hypoxia in the fetus has been extensively studied with regard to redistribution of fetal combined ventricular output and sparing of oxygen delivery to fetal brain and heart. However, little is known about the biochemical and molecular response of the fetal brain to transient hypoxia. The present study was designed to use transcriptomics and systems biology modeling to identify major biological responses of the fetal hypothalamus to transient hypoxia. We also investigated the effect of ketamine, an FDA approved anesthetic that has anti-inflammatory properties in various tissues. Chronically catheterized fetal sheep (122±5 days gestation) were subjected to 30 min hypoxia (relative reduction in PaO2 ~50 %) caused by infusion of nitrogen into the inspired gas of the pregnant ewe. Messenger RNA was isolated from fetal hypothalamus collected 24 hours after hypoxia, and was analyzed for gene expression using the Agilent 15.5k ovine microarray. Hypoxia increased expression of 280 and decreased expression of 357 genes. Genes increased by hypoxia were associated with immune responses, consistent with stimulation by lipopolysaccharide. Pretreatment of the fetuses with ketamine reduced immune/inflammation responses. Immunohistochemical analysis revealed that the number of microglia/macrophages in the anterior hypothalamus was increased by hypoxia and that the increase was blunted by ketamine. We conclude that transient hypoxia stimulates an inflammatory/immune response in the fetal hypothalamus and that transcriptomics/systems biology modeling is a useful and valid tool for investigation of biological function in the fetal sheep.
2017-07-31 | GSE82016 | GEO
Project description:We have previously shown in sheep that 10 days of modest chronic increase in maternal cortisol result in fetal heart enlargement and Purkinje cell apoptosis. In subsequent studies in which we extended the duration of cortisol infusion (1mg/kg/d) to term, we found a dramatic incidence of stillbirth in the pregnancies with chronically increased cortisol and associated maternal hyperglycemia. To investigate the effects on the heart, transcriptomic analyses were performed on the septa using ovine microarrays and Webgestalt and Cytoscape programs for pathway inference. Analyses of the effects of 10 days of maternal cortisol infusion (130d-cortisol vs 130d control), ~25 days (term at ~140d-cortisol vs 140d control), normal maturation (140d-control vs 130d control) were performed. In all analyses gene ontology (GO) terms related to immune function and cytokine actions were significantly over-represented. After 10 days of cortisol, growth factor and muscle cell apoptosis pathways were significantly over-represented, consistent with our previous findings. We found significantly differentially regulated genes in the term fetuses (ie after ~25 days of cortisol) in pathways consistent with altered metabolism in the heart, particularly in mitochondria, associated with responses to hypoxia and to nutrient. Analysis of mitochondrial number by quantitative real-time PCR confirmed a significant decrease. These pathways were different from those modeled following the normal increase in cortisol in late gestation which contributes to normal maturation of the heart, and thus may be indicative of the fetal heart pathophysiologies seen in pregnancies complicated by diabetes, CushingM-bM-^@M-^Ys disease and chronic stress. 2 cohorts of singleton sheep fetuses at 129-131d gestation or 139-144d gestation (approximately term) were used. The first cohort received maternal cortisol infusion of 1mg/kg/day or vehicle for 10 days until approximately day 130 of gestation (n=6/group), the second cohort received the same dose of cortisol for approximately 25 days until near term (n=7, cortisol; n=7ewes, n=8 fetuses due to one set of twins, control)
2014-08-07 | E-GEOD-54237 | biostudies-arrayexpress
Project description:To elucidate the impact of androgen exposure in fetal life on adolescent sheep, fetuses were exposed to either a vehicle control or testosterone propionate. Sheep were then reared to adolescence, and RNA was extracted from the liver to assess the impact of hormone exposure during fetal development.
2019-12-31 | E-MTAB-8032 | biostudies-arrayexpress