Project description:Environmental factors during perinatal development influence developmental plasticity and disease susceptibility via alterations to the epigenome. Developmental exposure to the endocrine active compound, bisphenol A (BPA), has previously been associated with altered methylation at candidate gene loci. Here, we undertake the first genome-wide characterization of DNA methylation profiles in the liver of murine offspring perinatally exposed to multiple doses of BPA through the maternal diet. Using a tiered focusing approach, our strategy proceeds from unbiased broad DNA methylation analysis using methylation-based next generation sequencing technology to in-depth quantitative site-specific CpG methylation determination using the Sequenom EpiTYPER MassARRAY platform to profile liver DNA methylation patterns in offspring maternally exposed to BPA during gestation and lactation to doses ranging from 0 BPA/kg (Ctr), 50 M-BM-5g BPA/kg (UG), or 50 mg BPA/kg (MG) diet (N=4 per group). Genome-wide analyses indicate non-monotonic effects of DNA methylation patterns following perinatal exposure to BPA, corroborating previous studies using multiple doses of BPA with non-monotonic outcomes. We observed enrichment of regions of altered methylation (RAMs) within CpG island (CGI) shores, but little evidence of RAM enrichment in CGIs. An analysis of promoter regions identified several hundred novel BPA-associated methylation events, and methylation alterations in the Myh7b and Slc22a12 gene promoters were validated. Using the Comparative Toxicogenomics Database, a number of candidate genes that have previously been associated with BPA-related gene expression changes were identified, and gene set enrichment testing identified epigenetically dysregulated pathways involved in metabolism and stimulus response. In this study, non-monotonic dose dependent alterations in DNA methylation among BPA-exposed mouse liver samples and their relevant pathways were identified and validated. The comprehensive methylome map presented here provides candidate loci underlying the role of early BPA exposure and later in life health and disease status. For this study, liver DNA from a subset of a/a wild-type animals was analyzed for full methylome characteristics: 1) standard diet (Ctr, n = 4 offspring; 2 male and 2 female); 2) 50 M-BM-5g BPA/kg diet (UG, n = 4 offspring; 2 male and 2 female); 3) 50 mg BPA/kg diet (MG, n = 4 offspring; 1 male and 3 female).

Project description:Environmental factors during perinatal development influence developmental plasticity and disease susceptibility via alterations to the epigenome. Developmental exposure to the endocrine active compound, bisphenol A (BPA), has previously been associated with altered methylation at candidate gene loci. Here, we undertake the first genome-wide characterization of DNA methylation profiles in the liver of murine offspring perinatally exposed to multiple doses of BPA through the maternal diet. Using a tiered focusing approach, our strategy proceeds from unbiased broad DNA methylation analysis using methylation-based next generation sequencing technology to in-depth quantitative site-specific CpG methylation determination using the Sequenom EpiTYPER MassARRAY platform to profile liver DNA methylation patterns in offspring maternally exposed to BPA during gestation and lactation to doses ranging from 0 BPA/kg (Ctr), 50 µg BPA/kg (UG), or 50 mg BPA/kg (MG) diet (N=4 per group). Genome-wide analyses indicate non-monotonic effects of DNA methylation patterns following perinatal exposure to BPA, corroborating previous studies using multiple doses of BPA with non-monotonic outcomes. We observed enrichment of regions of altered methylation (RAMs) within CpG island (CGI) shores, but little evidence of RAM enrichment in CGIs. An analysis of promoter regions identified several hundred novel BPA-associated methylation events, and methylation alterations in the Myh7b and Slc22a12 gene promoters were validated. Using the Comparative Toxicogenomics Database, a number of candidate genes that have previously been associated with BPA-related gene expression changes were identified, and gene set enrichment testing identified epigenetically dysregulated pathways involved in metabolism and stimulus response. In this study, non-monotonic dose dependent alterations in DNA methylation among BPA-exposed mouse liver samples and their relevant pathways were identified and validated. The comprehensive methylome map presented here provides candidate loci underlying the role of early BPA exposure and later in life health and disease status.

Project description:Bisphenol A (BPA) is primarily used to make polycarbonate plastic, with a global capacity of production exceeding 8 million tons per year. Biomonitoring studies with human urine, blood and tissue samples suggest that humans are subjected to widespread and continuous exposure to BPA. It has been well established that early life exposure to BPA predisposes the prostate gland to carcinogenesis later in life. However, it remains unknown if BPA exposure during adulthood induces benign or neoplastic pathology in the prostate. The main objective of the present study is to determine the effects of BPA exposures during adulthood on the prostate and to characterize the global transcriptional reprogramming underlying endocrine disruption by BPA. We elevated circulating levels of free BPA in Noble rats to the human-relevant internal dose range with BPA-filled Silastic implants while maintaining the physiological levels of testosterone (T) with T-filled implants. Cotreatment with T and 17β-estradiol (E2) was our reference regimen which induced preneoplastic and cancereous lesions. The T + low/high dose of BPA induced prostatic hyperplasia, low-grade prostate intraepithelial neoplasia (LGPIN) and intraepithelial infiltration of T-lymphocytes specifically in the lateral prostate (LP). Using microarray analysis, we delineated specific impacts of low and high dose of BPA (with the T-support) on the gene expression program in LPs. Hierarchical clustering revealed that the endocrine disrupting effects of T + low dose of BPA showed partial resemblance to those of T + high dose of BPA and T+E2. In contrast, the influence of T+ high dose of BPA on the LP transcriptome was completely different from those of T + E2. Further, IPA analysis of specific T+ low or high BPA gene signature identified a transcription factor, HNF4α, as a regulatory hub affecting a number of differentially expressed genes by BPA exposures. These findings suggest that the adult rat prostate is still venerable to the endocrine disrupting effects of BPA. Perhaps chronic exposure to low dose of BPA provides a niche comprising heightened cell proliferation, inflammatory responses and disrupted gene expression program, which favor the onset and development of prostatic benign or malignant diseases in men. Rat lateral prostates were collected from untreated control and treated groups [Testosterone (T) + Estradiol (E2), T + low dose Bisphenol A (low BPA) and T + high BPA] for RNA extraction and hybridization on Affymetrix microarrays. We sought to identify transcriptional signature of BPA exposures in the lateral prostate gland.

Project description:Purpose: the goal of this project is to study the effects of the bisphenol A (BPA) in the transcriptome profiling (RNA-seq) of exposed zebrafish larvae. Methods: Total RNA was isolated from the samples using AllPrep DNA/RNA Mini Kit (Qiagen, CA, USA) as described by the manufacturer. Three high quality sample per condition were chosen to the mRNA enrichment using KAPA Stranded mRNA-Seq Kit Illumina® Platforms (Kapa Biosystems). Transcriptomic profiles were generated by deep sequencing using Illumina TruSeq SBS Kit v3-HS (pair-ended; 2x76bp) on a HiSeq2000 sequencing system. Images analysis, base calling and quality scoring of the run were processed using the manufacturer’s software Real Time Analysis (RTA 1.13.48) and followed by generation of FASTQ sequence files by CASAVA. Statistical analysis: RNA-seq reads were aligned to the D. rerio reference genome (GRCz10) using STAR version 2.5.1b . Genes annotated in GRCz10.84 were quantified using RSEM version 1.2.28 with default parameters. Differential expression analysis between all BPA conditions was performed with the DESeq2 (v.1.10.1) R package with the Likelihood ratio test option. ANOVA-PLS was performed on the normalized data using the lmdme package in R (v. 1.0.136, R Core Team). Results: We generated on average 40 million paired-end reads for each sample and identified aproximatelly 25000 transcripts. 2539 differentially expressed genes (DEGs) were detected which could be divided in 3 clusters including 960, 1132 and 447 genes, respectively. Affected metabolic pathways were analyzed from the DEGs: liver development, lipid transport, lysosome and protein glycosylation, metabolic pathways for lipids, glutathione, retinol, and steroid hormones, and cytochrome P450-mediated metabolism in adittion to protein ubiquitination and glycolysis/gluconeogenesis pathways' were down or upregulated. Conclusions: The results suggest the interaction of BPA with different signaling pathways, being the estrogenic and retinoid receptors two likely BPA targets. We concluded that our analysis allowed us the identification of underlying molecular mechanisms occurring simultaneously at the exposed animals. While this approach is very useful to analyze the effects of compounds, like BPA, able to interact with different cellular targets, we believe that it can be also applied to the characterization of the different toxic components present in complex natural mixtures.

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