Project description:Exposure to Propylthiouracil in Pregnant Mice Potentiates the Transcriptional Response to Thyroid Hormone in the Fetal Cerebral Cortex
Project description:Astrocytes mediate the action of thyroid hormone in the brain on other neural cells through the production of the active hormone triiodothyronine (T3) from its precursor thyroxine (T4). T3 has also many effects on the astrocytes in vivo and in culture, but whether these actions are directly mediated by transcriptional regulation is not clear. In this work, we have analyzed the genomic response to T3 of cultured astrocytes isolated from the postnatal mouse cerebral cortex, using RNA sequencing. Cultured astrocytes express relevant genes of thyroid hormone metabolism and action encoding type 2 deiodinase (Dio2), Mct8 transporter (Slc16a2), T3 receptors (Thra1 and Thrb), and nuclear corepressor (Ncor1) and coactivator (Ncoa1). T3 changed the expression of 668 genes (4.5% of expressed genes), of which 117 genes (0.8% of expressed genes) were primary, transcriptional responses. The Wnt and Notch pathways were down-regulated at the post-transcriptional level. Comparison with the effect of T3 on astrocyte-enriched genes in mixed cerebrocortical cultures isolated from fetal cortex revealed that the response to T3 is influenced by the degree of astrocyte maturation, and that in agreement with its physiological effects, T3 promotes the transition between the fetal and adult patterns of gene expression.
Project description:Timed pregnant C57Bl6 mice were exposed to ethanol during a critical period, gestational day 15 to 18, of cerebral cortical development to identify gene expression changes in the cerebral cortex of developing fetus due to this ethanol exposure Keywords: Compared animals exposed to ethanol (alcohol fed group) to a pair-fed control group and both groups were normalized to a control group (animals fed adlibitum)
Project description:A dataset for coordinated transcriptome analysis of the effect of ethanol on human embryonic cerebral slices in vitro and on the mouse embryonic cerebral cortex in a in vivo model. GW15 and 17 embryonic cortices that were obtained from the Human Fetal Tissue Repository at Albert Einstein College of Medicine. The research protocol was approved by Yale Human Investigation Committee. The medical histories of all samples did not present exposure to alcohol during pregnancy. The tissues were stored in L-15 Leibovitz medium on ice and were cut at 300 µm using a tissue chopper within 3 hours after the surgery. the slices were cultured on the membrane floating on the Neurobasal medium containing 50 mM ethanol or PBS with supplements for 24 hours in tissue culture plate with low evaporation lid (falcon, 353046). Wild-type CD-1 pregnant mice were purchased from Charles River. For the mouse in vivo mFAE model, the pregnant dams of wild-type and transgenic mice were intraperitoneally injected with 25% ethanol/PBS (final 2.0g/kg weight) or PBS (as the control) once a day from E14 to E16.
Project description:Although the effects of thyroid hormones (TH) on the brain development have been extensively studied perinatally, effects of TH of maternal origin on the fetal brain development have been largely unexplored. We applied a high throughput study on the mouse models with aberrant TH levels on gestation day (GD) 16, before the onset of fetal thyroid function. Although 3 day treatment with methimazole (MMI) and perchlorate significantly decreased TH levels in fetal cerebral cortex, few changes in the abundance of mRNA were revealed by the microarray analysis. Injection TH to dams 12 hours before sacrifice on GD 16 induced 161 genes significantly changed in fetal cortex. Nine out of 10 selected genes were confirmed with RT-PCR, including known TH responsive gene Klf9 and other novel TH responsive genes such as Appbp2, Ppap2b and Fgfr1op2. TH regulation of the expression of these genes was also confirmed with cultured N2a? cells. Thyroid responsive elements (TREs) in the promoters of these genes were identified using electrophoresis mobility shift assay. TH effect on microRNA (miRNA) expression in developing cortex on GD 16 and postnatal day (PND) 15 was investigated with microarray and RT-PCR. Some of miRNAs and precursors decreased in fetal cortex from the dams injected with TH on GD 16, including miR-16 and miR-106. Using 3’ untranslate region reporter vector, we identified Klf9 is one of the target genes of miR-106, while Ppap2b is the target of miR-16. These results indicated that TH regulation on gene expression could through TR-TRE interaction and through regulating target miRNA expression. This study is the first report to identify TH responsive genes and miRNAs genome wide in the early fetal brain; it provides evidence to further understand the mechanism of TH effect on brain development. Timed-pregnant C57BL/6 mice (n=20; Harlan, Indianapolis, IN) arrived on gestational day (GD) 11 and were housed individually in plastic cages under a 12:12 light cycle (0600 h–1800 h) with food available ad libitum. Mice were divided randomly into one of 4 groups (control, hypo, hypo+ and hyper; 5 per group) . Mice in the control and hyper groups were provided with fresh drinking water containing 2% sucrose from GD 13 to GD 16 until sacrifice. Mice in hypo and hypo+ were provided with fresh drinking water daily containing 1% Perchlorate (Per) and 0.025% Methimazole (MMI) supplemented with 2% sucrose (to mask bitterness) from GD 13 to sacrifice on GD 16. Twelve hours prior to sacrifice on GD 16 all mice received a single subcutaneous injection. Control and hypo mice received vehicle (0.9% saline in 100 µl volume); the hypo+ group received 25.0 µg/100g body weight thyroxine (T4) with 2.5 µg/100g body weight T3 to restore a physiological level of TH; the hyper group received 100.0 µg/100g body weight T4 with 10.0 µg/100g body weight T3 to model hyperthyroidism. Dams were killed by exposure to CO2. Fetuses were dissected from the uterine horn and embryonic membranes then frozen on pulverized dry ice. Tissue samples were taken from the fetuses to determine sex using PCR for SRY (Yang J and RT Zoeller, 2002). Fetal cerebral cortices were removed from each mouse and used for microarray and RT-PCR analysis. Total RNA was extracted from half cortices of individual female fetuses using RNeasy Lipid tissue Mini kits (Qiagen, Germantown, MD) according to the manufacturer's instructions. The quality of total RNA was evaluated by A260/A280 ratio (found to be at least 1.8 for each sample) and by electrophoresis on the Agilent Bioanalyzer. The Yale Center for the Neuroscience Microarray Consortium carried out the Affymetrix microarray analysis using The GeneChip Rat Genome 230 2.0 Array. Preparation of labeled cRNA for hybridization onto Affymetrix GeneChips followed the recommended Affymetrix protocol. Control versus each of the three treatment groups: hyper, hypo, and hypo+. 1 of 20 samples removed due to poor quality.
Project description:In a recent egg injection study, we showed that in ovo exposure to perfluorohexane sulfonate (PFHxS) affects the pipping success of developing chicken (Gallus gallus domesticus) embryos. We also found evidence of thyroid hormone (TH) pathway interference at multiple levels of biological organization (i.e. somatic growth, mRNA expression and circulating free thyroxine levels). Based on these findings, we hypothesize that PFHxS exposure interferes with TH-dependent neurodevelopmental pathways. The present study investigates global transcriptional profiles of cerebral cortex tissue from chicken embryos following exposure to a solvent control, 890 or 38,000 ng PFHxS/g egg (n=4-5 per group); doses which lead to the adverse effects above. PFHxS significantly alters the expression (≥1.5-fold, p≤0.001) of 11 transcripts at the low dose (LD; 890 ng/g) and 101 transcripts at the high dose (HD; 38,000 ng/g). Functional enrichment analysis shows that PFHxS affects genes involved in tissue development and morphology, cellular assembly and organization, and cell-to-cell signalling. Pathway and interactome analyses suggest that genes may be affected through several potential regulatory molecules, including integrin receptors, myelocytomatosis viral oncogene and CCAAT/enhancer binding protein. This study identifies key functional and regulatory modes of PFHxS action involving TH-dependent and -independent neurodevelopmental pathways. Some of these TH-dependent mechanisms that occur during embryonic development include tight junction formation, signal transduction and integrin signaling, while TH-independent mechanisms include gap junction intercellular communication. Reference Design. Reference = pool of equal parts of all control and treated samples. Control groups and 2 treatment groups. Control samples were chicken embryonic cerebral cortex exposed DMSO only (solvent). Treatments were: chicken embryonic cerebral cortex exposed to 890 ng/g PFHxS (LD) and 38,000 ng/g PFHxS (HD).
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.
Project description:Background: Prenatal exposure to air pollutants is associated with increased risk for neurodevelopmental and neurodegenerative disorders. However, few studies have identified transcriptional changes related to air pollutant exposure. Methods: RNA sequencing was used to examine transcriptomic changes in blood and cerebral cortex of three male and three female mouse neonates prenatally exposed to traffic-related nano-sized particulate matter (nPM) compared to three male and three female mouse neonates prenatally exposed to control filter air. Results: We identified 19 nPM-associated differentially expressed genes (nPM-DEGs) in blood and 124 nPM-DEGs in cerebral cortex. The cerebral cortex transcriptional responses to nPM suggested neuroinflammation involvement, including CREB1, BDNF, and IFN γ genes. Both blood and brain tissues showed nPM transcriptional changes related to DNA damage, oxidative stress, and immune responses. Three blood nPM-DEGs showed a canonical correlation of 0.98 with 14 nPM-DEGS in the cerebral cortex, suggesting a convergence of gene expression changes in blood and cerebral cortex. Exploratory sex-stratified analyses suggested a higher number of nPM-DEGs in female cerebral cortex than male cerebral cortex. The sex-stratified analyses identified 2 nPM-DEGs (Rgl2 and Gm37534) shared between blood and cerebral cortex in a sex-dependent manner. Conclusions: Our findings suggest that prenatal nPM exposure induces transcriptional changes in the cerebral cortex, some of which are also observed in blood. Further research is needed to replicate nPM-induced transcriptional changes with additional biologically relevant time points for brain development.
Project description:To investigate the effects of administration of carbon black nanoparticle (CB-NP) to pregnant mice on the brain development in infantile mice, we have employed whole-genome microarray expression profiling to identify genes which show dose-dependent differential expression with astrogliosis in the frontal cortex of offspring mice. Some pregnant mice were pretreated with ascorbic acid to investigate the mechanism underlying the CB-NP effect. In addition to the frontal cortex of offspring mice who were exposed to CB-NP maternally, placenta was also subjected to the analysis to investigate the mechanism. Pregnant mice were intranasally exposed to 0, 2.9, 15, 73, or 95 micro gram of CB-NP (Printex 90) per kg (body weight) on gestational days (GDs) 5 and 9. Some pregnant mice were treated with intraperitoneal injection of ascorbic acid (500 mg/kg) at 1 h before the CB-NP instillation (95 μg/kg). Placentae were collected from pregnant dams on GD 13. Dissected cerebral cortex were collected from 6- and 12-week-old offspring mice.
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.