ERα Dependent Alterations in the Epigenetic Landscape of the Mouse Uterus Following Neonatal Estrogen Exposure [RNA-Seq]
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ABSTRACT: Abstract. Very little is known regarding how hormonal exposures impact the epigenetic landscape of developing tissues in the context of a whole organism, in contrast to the impact on cultured cells. Here we took a global approach to understanding how neonatal exposure to the xenoestrogen, diethylstilbestrol (DES), alters the uterine epigenome. RNA-seq and ChIP-seq (H3K4me3, H3K27me3, H3K27ac and H3K4me1) were performed on DES-treated and control uteri. The most striking finding was differential association of H3K27ac and H3K4me1 at typical and super-enhancer regions of 79% of altered genes. These peaks overlapped with previously reported estrogen receptor a (ERα) ChIP-seq peaks. Conditional uterine deletion of ERα (Esr1cKO) conferred protection of 88% of altered genes. H3K27ac ChIP-seq on Esr1cKO samples showed that 72% of protected genes had a differential H3K27ac enhancer. These data suggest that DES regulates gene expression in the neonatal mouse uterus by H3K27ac association at ERα binding sites near estrogen-regulated genes.
Project description:Abstract. Very little is known regarding how hormonal exposures impact the epigenetic landscape of developing tissues in the context of a whole organism, in contrast to the impact on cultured cells. Here we took a global approach to understanding how neonatal exposure to the xenoestrogen, diethylstilbestrol (DES), alters the uterine epigenome. RNA-seq and ChIP-seq (H3K4me3, H3K27me3, H3K27ac and H3K4me1) were performed on DES-treated and control uteri. The most striking finding was differential association of H3K27ac and H3K4me1 at typical and super-enhancer regions of 79% of altered genes. These peaks overlapped with previously reported estrogen receptor a (ERα) ChIP-seq peaks. Conditional uterine deletion of ERα (Esr1cKO) conferred protection of 88% of altered genes. H3K27ac ChIP-seq on Esr1cKO samples showed that 72% of protected genes had a differential H3K27ac enhancer. These data suggest that DES regulates gene expression in the neonatal mouse uterus by H3K27ac association at ERα binding sites near estrogen-regulated genes.
Project description:Neonatal exposure to diethylstilbestrol (DES) results in abnormal reproductive tract morphology, female infertility and uterine cancer in mice. This exposure also causes altered gene expression in the female reproductive tract that persists into adulthood. To further explore on a genome-wide basis how neonatal estrogen exposure results in permanent epigenetic changes, we performed RNA-seq and ChIP-seq analyses of DES-treated and control mice. CD-1 mice were treated on postnatal days (PND) 1-5 with DES (2 µg/pup/day) or corn oil as a control; uterine tissues were collected on PND5. RNA-seq analysis resulted in 4,498 differentially expressed genes (>1.5 fold difference; RPKM >1; FDR <0.05). ChIP-seq was performed on uterine samples using H3K4me3, H3K27me3, H3K27acetyl and H3K4me1 as the precipitating antibodies. The most significant findings at the TSS were increased H3K4me3 at up-regulated genes (22%), increased H3K27ac at up-regulated genes (55%) and differential H3K27ac at down-regulated genes (33%). The most striking finding was differential association of H3K27ac at presumed enhancer regions; 3,012 out of 4498 altered genes (67%) had a differential H3K27ac peak associated with them and 2,962 out of 4,498 (66%) had differential H3K4me1. These differences were generally coordinated with gene expression with increased gene expression having more H3K27ac associated although a small subset of genes showed the opposite. To further investigate the mechanism of differential H3K27ac binding in enhancer regions near estrogen regulated genes, we overlapped these enhancers to Esr1 ChIP seq data; a large percentage of them overlap with Esr1 peaks (39%). We also performed motif analysis where ERE was enriched in the differential H3K27ac peaks. We further investigated Esr1’s role in differential H3K27ac enhancer binding by using a conditional uterine deletion of Esr1 by crossing Esr1 floxed mice with PgR-cre and then treating with vehicle or DES and collecting uteri on day 5. We performed a microarray and pattern analysis and determined there were 4,073 out of 4,617 altered genes (88%) protected by conditional uterine deletion of Esr1. We also performed H3K27ac ChIP seq on these samples and found a large number of these protected genes have a differential H3K27ac enhancer. Several Fox genes were up-regulated following DES treatment and Fox binding motifs were found to be enriched in both H3K27ac and H3K4me1 differential enhancer peaks. To further study the impact of Foxa2 or Foxo1, we conditionally deleted each of these using PgR-cre. There were far fewer genes impacted by deletion of either Foxa2 or Foxo1 suggesting these Fox genes are not responsible for DES induced gene expression and these two lines were not followed further. Taken together, these data suggest estrogen regulates gene expression in the neonatal mouse uterus by H3K27ac association at Esr1 binding sites near estrogen regulated genes. Changes in the epigenome during the time of treatment may contribute to the permanent alterations in gene expression observed in aged DES treated mice.
Project description:Developmental exposure to diethylstilbestrol (DES) causes reproductive tract malformations, affects fertility and increases the risk of clear cell carcinoma of the vagina and cervix in humans. Previous studies on a well-established mouse DES model demonstrated that it recapitulates many features of the human syndrome, yet the underlying molecular mechanism is far from clear. Using the neonatal DES mouse model, the present study uses global transcript profiling to systematically explore early gene expression changes in individual epithelial and mesenchymal compartments of the neonatal uterus. Over 900 genes show differential expression upon DES treatment in either one or both tissue layers. Interestingly, multiple components of the Peroxisome Proliferator-Activated Receptor gamma (PPAR gamma)-mediated adipogenic/lipid metabolic pathway, including PPARgamma itself, are targets of DES in the neonatal uterus. TEM and Oil Red O staining further demonstrate a dramatic increase in lipid deposition in the uterine epithelial cells upon DES exposure. Neonatal DES exposure also perturbs glucose homeostasis in the uterine epithelium. Some of these neonatal DES-induced metabolic changes appear to last into adulthood, suggesting a permanent effect of DES on energy metabolism in uterine epithelial cells. This study extends the list of biological processes that can be regulated by estrogen or DES, and provides a novel perspective for endocrine disruptor induced reproductive abnormalities.
Project description:The estrogen receptor-α (ERα) is a transcription factor which plays a critical role in controlling cell proliferation and tumorigenesis by recruiting various cofactors to estrogen response elements (EREs) to induce or repress gene transcription. A deeper understanding of these transcriptional mechanisms may uncover novel therapeutic targets for ERα-dependent cancers. Here we show for the first time that BRD4 regulates ERα−induced gene expression by affecting elongation-associated phosphorylation of RNA Polymerase II (RNAPII P-Ser2) and histone H2B monoubiquitination (H2Bub1). Consistently, BRD4 activity is required for estrogen-induced proliferation of ER+ breast and endometrial cancer cells and uterine growth in mice. Genome-wide occupancy studies revealed an enrichment of BRD4 on transcriptional start sites as well as EREs enriched for H3K27ac and demonstrate a requirement for BRD4 for H2B monoubiquitination in the transcribed region of estrogen-responsive genes. Importantly, we further demonstrate that BRD4 occupancy correlates with active mRNA transcription and is required for the production of ERα-dependent enhancer RNAs (eRNAs). These results uncover BRD4 as a central regulator of ERα function and potential therapeutic target. ChIP-sequencing of BRD4, ERα and H2Bub1 in MCF7 cells treated with +/- estrogen treatment and or +/- JQ1 treatment in triplicates.
Project description:Developmental exposure to diethylstilbestrol (DES) causes reproductive tract malformations, affects fertility and increases the risk of clear cell carcinoma of the vagina and cervix in humans. Previous studies on a well-established mouse DES model demonstrated that it recapitulates many features of the human syndrome, yet the underlying molecular mechanism is far from clear. Using the neonatal DES mouse model, the present study uses global transcript profiling to systematically explore early gene expression changes in individual epithelial and mesenchymal compartments of the neonatal uterus. Over 900 genes show differential expression upon DES treatment in either one or both tissue layers. Interestingly, multiple components of the Peroxisome Proliferator-Activated Receptor gamma (PPAR gamma)-mediated adipogenic/lipid metabolic pathway, including PPARgamma itself, are targets of DES in the neonatal uterus. TEM and Oil Red O staining further demonstrate a dramatic increase in lipid deposition in the uterine epithelial cells upon DES exposure. Neonatal DES exposure also perturbs glucose homeostasis in the uterine epithelium. Some of these neonatal DES-induced metabolic changes appear to last into adulthood, suggesting a permanent effect of DES on energy metabolism in uterine epithelial cells. This study extends the list of biological processes that can be regulated by estrogen or DES, and provides a novel perspective for endocrine disruptor induced reproductive abnormalities. We separated UE from the UM from vehicle (oil)- or DES-treated postnatal day 5 (P5) mice, and prepared biological triplicates of RNA from pooled specimens (nM-bM-^IM-%3). Those samples were analyzed on two MouseWG-6 BeadChips, which detects 45,200 transcripts including more than 26,000 annotated genes in the NCBI RefSeq database. Difference of at least twofold in signal intensity of each given probe set with a P-value less than 0.05 was considered statistically significant.
Project description:To advance understanding of mechanisms leading to biological and transcriptional endpoints related to estrogen action in the mouse uterus, we have mapped ERα and RNA polymerase II binding sites using chromatin immunoprecipitation (ChIP) followed by sequencing of enriched chromatin fragments (ChIP-seq). In the absence of hormone, 5184 ERα binding sites were apparent in the vehicle treated ovariectomized uterine chromatin, while 17240 were seen one hour after estrogen (E2) treatment, indicating that some sites are occupied by unliganded ERα, and that ERα binding is increased by E2. Approximately 15% of the uterine ERα binding sites were adjacent to (<10 KB) annotated transcription start sites and many sites are found within genes or are found more than 100 KB distal from mapped genes; however, the density (sites per bp) of ERα binding sites is significantly greater adjacent to promoters. An increase in quantity of sites but no significant positional differences were seen between vehicle and E2 treated samples in the overall locations of ERα binding sites either distal from, adjacent to or within genes. Analysis of the PolII data revealed the presence of poised promoter proximal PolII on some highly upregulated genes. Additionally, co-recruitment of PolII and ERα to some distal enhancer regions was observed. A de novo motif analysis of sequences in the ERα bound chromatin confirmed that estrogen response elements (EREs) were significantly enriched. Interestingly, in areas of ERα binding without predicted ERE motifs, homeodomain transcription factor (Hox) binding motifs were significantly enriched. The integration of the ERα and PolII binding sites from our uterine ChIP-seq data with transcriptional responses revealed in our uterine microarrays has the potential to greatly enhance our understanding of mechanisms governing estrogen response in uterine and other estrogen target tissues.
Project description:ERα binding activity largely depends on access to binding sites on chromatin, which is facilitated in part by Pioneer Factors (PFs).We show that most binding events of NR2F2 occur together with the ERα binding sites.To explore whether NR2F2 may act as potential pioneer factor of ER, we performed a series of ChIP-seq genome wide in MCF-7. Since NR2F2 associates with chromatin prior to estrogen treatment and its depletion in MCF-7 cells did not affect ERα expression, we hypothesize NR2F2 may inhibit estrogen-dependent growth by modulating ERα recruitment. We performed ChIP-seq genome wide gainst ERα before and after NR2F2 depletion.Covalent modifications are a main chromatin property.To test whether NR2F2 favoured histone modification deposition on chromatin, we profiled ChIP-Seq of H3K4me1, H3K4me3, and H3K27ac following NR2F2 depletion in oestrogen-starved MCF-7 cells to gain comprehensive histone medication landscape.
Project description:Estrogen (E2) signaling through its nuclear receptor, estrogen receptor α (ERα) increases insulin-like growth factor 1 (IGF1) in the rodent uterus, which then initiates further signals via the IGF1 receptor (IGF1R). Directly administering IGF1 results in similar biological and transcriptional uterine responses. Our studies using global ERα-null mice demonstrated a loss of uterine biological responses of the uterus to E2 or IGF1 treatment, while maintaining transcriptional responses to IGF1. To address this discrepancy in the need for uterine ERα in mediating the IGF1 transcriptional vs. growth responses, we assessed the IGF1 transcriptional responses in PgrCre+Esr1f/f (called ERαUtcKO) mice, which selectively lack ERα in progesterone receptor (PGR) expressing cells, including all uterine cells, while maintaining ERα expression in other tissues and cells that do not express Pgr. Additionally, we profiled IGF1-induced ERα binding sites in uterine chromatin using ChIP-seq. Herein, we explore the transcriptional and molecular signaling that underlies our findings to refine our understanding of uterine IGF1 signaling and identify ERα-mediated and ERα-independent uterine transcriptional responses. Defining these mechanisms in vivo in whole tissue and animal contexts provides details of nuclear receptor mediated mechanisms that impact biological systems and have potential applicability to reproductive processes of humans, livestock and wildlife.
Project description:Estrogen (E2) signaling through its nuclear receptor, estrogen receptor α (ERα) increases insulin-like growth factor 1 (IGF1) in the rodent uterus, which then initiates further signals via the IGF1 receptor (IGF1R). Directly administering IGF1 results in similar biological and transcriptional uterine responses. Our studies using global ERα-null mice demonstrated a loss of uterine biological responses of the uterus to E2 or IGF1 treatment, while maintaining transcriptional responses to IGF1. To address this discrepancy in the need for uterine ERα in mediating the IGF1 transcriptional vs. growth responses, we assessed the IGF1 transcriptional responses in PgrCre+Esr1f/f (called ERαUtcKO) mice, which selectively lack ERα in progesterone receptor (PGR) expressing cells, including all uterine cells, while maintaining ERα expression in other tissues and cells that do not express Pgr. Additionally, we profiled IGF1-induced ERα binding sites in uterine chromatin using ChIP-seq. Herein, we explore the transcriptional and molecular signaling that underlies our findings to refine our understanding of uterine IGF1 signaling and identify ERα-mediated and ERα-independent uterine transcriptional responses. Defining these mechanisms in vivo in whole tissue and animal contexts provides details of nuclear receptor mediated mechanisms that impact biological systems and have potential applicability to reproductive processes of humans, livestock and wildlife.
Project description:Estrogen receptor α (ERα) modulates gene expression through interactions with enhancer regions of chromatin that are frequently distal from the promoters of estrogen regulated genes. Active chromatin enriched “super-enhancer” (SE) regions, mainly described in in vitro culture systems, often control production of key cell type determining transcription factors. Here, we define ERα binding super-enhancers in vivo within hormone responsive uterine tissue. SE are already formed prior to estrogen exposure at the onset of puberty. The SE encode critical developmental factors including Rara and Hoxd. Using chromosome conformation capture with high throughput sequencing (Hi-C) we demonstrate that most ERα-binding SE are located at a chromatin loop end and most uterine genes in loop ends associated with ERα-binding SEs are estrogen regulated. Although SE are formed prior to puberty, SE-associated genes acquire optimal ERα dependent expression after reproductive maturity, indicating estrogen impacts enhancer function subsequent to assembly. ERα-binding SE-associated genes impact key uterine functions mediated by estrogen, including TGFβ and LIF signaling pathways. This is the first identification of ERα-binding SE interactions underlying hormonal regulation of genes in uterine tissue and optimal development of estrogen response