Unknown,Transcriptomics,Genomics,Proteomics

Dataset Information

Cultured Cyto and Syncytio-trophoblast samples exposed to varying degrees of hypoxia (expression)

ABSTRACT: The mechanisms by which the placenta adapts to exogenous stimuli to create a stable and healthy environment for the growing fetus are not well known. Low oxygen tension and sub-optimal vitamin D levels influence placental function and both are associated with preeclampsia, a condition associated with altered development of placental trophoblast. We hypothesized that oxygen tension, vitamin D levels, or both affect villous trophoblast by modulation of gene expression through DNA methylation. To test this we used the Illumina Infinium Human Methylation 450 BeadChip array to compare the DNA methylation profile of primary cultures of human cytotrophoblasts and syncytiotrophoblasts under three oxygen tensions and three vitamin D levels. We found no effect on global DNA methylation by either treatment, but a limited set of loci became hypermethylated in cytotrophoblasts exposed for 24 hours to 1% oxygen, as compared to the same cells exposed to 8% or 20% oxygen. Vitamin D levels had no detectable effect on methylation profiles in either trophoblast type. Hypermethylation with low oxygen tension was independently confirmed by bisulfite-pyrosequencing in a subset of functionally important genes including CP, ITGA5, SOD2, XDH and ZNF2. Intriguingly, 70 out of the 147 hypoxia-associated CpGs, overlapped with CpG sites that become hypomethylated upon differentiation of cytotrophoblasts into syncytiotrophoblasts. Furthermore, the preponderance of altered sites was located at AP-1 binding sites. We suggest that AP-1 expression is triggered by hypoxia and interacts with DNA methyltransferases (DNMTs) to target methylation at specific sites in the genome, thus causing suppression of the associated genes that are responsible for differentiation of villous cytotrophoblast to syncytiotrophoblast. RNA from cytotrophoblast from 2 placentas exposed to 3 different conditions of hypoxia (1%,8%,20%) and treated with 3 levels of vitamin D were run on the Illumina HT-12v4 Expression Array

ORGANISM(S): Homo sapiens

SUBMITTER: John Blair

PROVIDER: E-GEOD-41331 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

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Publications

Hypoxia alters the epigenetic profile in cultured human placental trophoblasts.

Yuen Ryan K C RK Chen Baosheng B Blair John D JD Robinson Wendy P WP Nelson D Michael DM

Epigenetics 20130111 2

The mechanisms by which the placenta adapts to exogenous stimuli to create a stable and healthy environment for the growing fetus are not well known. Low oxygen tension influences placental function, and is associated with preeclampsia, a condition displaying altered development of placental trophoblast. We hypothesized that oxygen tension affects villous trophoblast by modulation of gene expression through DNA methylation. We used the Infinium HumanMethylation450 BeadChip array to compare the D ...[more]

PMID: 23314690

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Project description:The mechanisms by which the placenta adapts to exogenous stimuli to create a stable and healthy environment for the growing fetus are not well known. Low oxygen tension and sub-optimal vitamin D levels influence placental function and both are associated with preeclampsia, a condition associated with altered development of placental trophoblast. We hypothesized that oxygen tension, vitamin D levels, or both affect villous trophoblast by modulation of gene expression through DNA methylation. To test this we used the Illumina Infinium Human Methylation 450 BeadChip array to compare the DNA methylation profile of primary cultures of human cytotrophoblasts and syncytiotrophoblasts under three oxygen tensions and three vitamin D levels. We found no effect on global DNA methylation by either treatment, but a limited set of loci became hypermethylated in cytotrophoblasts exposed for 24 hours to 1% oxygen, as compared to the same cells exposed to 8% or 20% oxygen. Vitamin D levels had no detectable effect on methylation profiles in either trophoblast type. Hypermethylation with low oxygen tension was independently confirmed by bisulfite-pyrosequencing in a subset of functionally important genes including CP, ITGA5, SOD2, XDH and ZNF2. Intriguingly, 70 out of the 147 hypoxia-associated CpGs, overlapped with CpG sites that become hypomethylated upon differentiation of cytotrophoblasts into syncytiotrophoblasts. Furthermore, the preponderance of altered sites was located at AP-1 binding sites. We suggest that AP-1 expression is triggered by hypoxia and interacts with DNA methyltransferases (DNMTs) to target methylation at specific sites in the genome, thus causing suppression of the associated genes that are responsible for differentiation of villous cytotrophoblast to syncytiotrophoblast. DNA from 2 cell types from 5 placentas exposed to 3 different conditions of hypoxia (1%,8%,20%) and treated with 3 levels of vitamin D were bisulfite converted and run on the Illumina HumanMethylation450 BeadChip

Project description:Human monocyte-derived dendritic cells (moDCs) have been used as an in vitro model for studying tolerance and immunity. However, the underlying metabolic states of tolerogenic (dexamethasone and vitamin D3-treated), immature and immunogenic (mature, LPS-treated) moDCs have not been completely characterized. Through transcriptomic analyses, we determined that tolerogenic moDCs exhibit augmented catabolic pathways with respect to oxidative phosphorylation (OXPHOS), fatty acid oxidation (FAO) and glycolysis. Functionally, tolerogenic moDCs showed the highest mitochondrial membrane potential, production of reactive oxygen species and superoxide, and increased mitochondrial spare respiratory capacity. Tolerogenic and mature moDCs manifested differential FAO gene expression with FAO activity being significantly higher in tolerogenic and immature moDCs than in mature. In addition, tolerogenic and mature moDCs demonstrated similar levels of glycolytic rate, but not glycolytic capacity and reserve, which were more pronounced in tolerogenic and immature moDCs. Finally, tolerogenic and immature moDCs, but not mature moDCs, showed high plasticity to compensate the intracellular ATP content after inhibition of different energetic metabolic pathways. Overall, tolerogenic moDCs exhibit a metabolic signature of increased, stable OXPHOS programing and high plasticity for metabolic adaptation. These findings provide a framework for future research of metabolic properties of human DCs. Total RNA of sixteen samples from four moDC types (tolerogenic, LPS-tolerogenic, immature and mature) were extracted by Trizol (Invitrogen) followed by a clean-up procedure using RNeasy Micro Kit (Qiagen). All RNA samples had an integrity number ≥9.6 assessed by Agilent Bioanalyzer. Total RNA samples were amplified using TargetAmp™ and the biotinilated cRNA was prepared by Nano-g™ Biotin-aRNA Labeling Kit for the Illumina® System (Epicentre). After the hybridization to the Illumina Human HT-12 v4 Beadchips for 17 h at 58°C, the arrays were washed, stained (Illumina Wash Protocol) and then scanned using BeadArray Scanner 500GX. Array data were extracted at the probe level without background correction using Illumina GenomeStudio software. These raw data were quantile normalized and log2 transformed. Technical replicates were obtained from the hybridization in duplicate of three samples. Pearson correlation analysis showed high correlation between the technical replicates (r>0.99). Differentially expressed genes (DEGs) were identified using Limma16 with Benjamini-Hochberg multiple testing correction (p<0.05). DEGs were further clustered into different groups according to the patterns of expression change among the different moDC types using STEM software17. The analysis was performed in R v.2.12.2 (http://www.R-project.org) with Bioconductor 2.12 (http://www.bioconductor.org) and enabled by Pipeline Pilot (www.accelrys.com).

Dataset Information

Cultured Cyto and Syncytio-trophoblast samples exposed to varying degrees of hypoxia (expression)

Publications

Hypoxia alters the epigenetic profile in cultured human placental trophoblasts.

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