Exposure to bisphenol A (BPA), an endocrine disruptor (ED), has raised concerns for both human and ecosystem health. Epigenetic factors, including microRNAs, are key regulators of gene expression during cancer. The effect of BPA exposure on the zebrafish epigenome remains poorly characterized. Zebrafish represents an excellent model to study cancer as the organism develops disease that resembles human cancer. Using zebrafish as systems toxicology model, we hypothesized that chronic BPA-exposure impacts the miRNome in adult zebrafish and establishes an epigenome more susceptible to cancer development. After a 21 day exposure to 100 nM BPA, RNA from the liver was extracted to perform high throughput mRNA and miRNA sequencing. Differential expression (DE) analyses comparing BPA-exposed to control specimens were performed using established bioinformatics pipelines. In the BPA-exposed liver, 6,188 mRNAs and 15 miRNAs were differently expressed (q = 0.1). By analyzing human orthologs of the DE zebrafish genes signatures associated with non-alcoholic fatty liver disease (NAFLD), oxidative phosphorylation, mitochondrial dysfunction and cell cycle were uncovered. Chronic exposure to BPA has a significant impact on the liver miRNome in adult zebrafish and has the potential to cause adverse outcomes including cancer. Overall design: Examination of transcriptome changes in an in vivo model organism exposed to a common, environmental compound.
The Plasticizer Bisphenol A Perturbs the Hepatic Epigenome: A Systems Level Analysis of the miRNome.
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View SamplesIn germ cells, Piwi proteins interact with a specific class of small non-coding RNAs, piwi-interacting RNAs (piRNAs). Together, these form a pathway that represses transposable elements, thus safeguarding germ cell genomes. While basic models describe the operation of piRNA pathways, neither the protein compositions of Piwi complexes, the critical protein-protein interactions that drive small RNA production and target recognition, or the precise molecular consequences of conserved localization to germline structures, call nuage, is well understood. We purified the three murine Piwi family proteins, Mili, Miwi, and Miwi2, from mouse germ cells and characterized their interacting protein partners. Piwi proteins were found in complex with Prmt5/Wdr77, an enzyme that di-methylates arginine residues. By immunoprecipitation with specific antibodies and by mass spectrometry, we found that Piwi proteins are arginine methylated at conserved positions in their amino termini. These modifications are essential to direct complex formation with specific Tudor-domain proteins, whose interactions with Piwis can be required for localization of RNP complexes in cytoplasmic nuage, proper piRNA expression, and transposon silencing. Considered together, our findings indicate that arginine methylation drives the assembly of multi-protein machines whose integrity and specific sub-cellular localization is necessary for efficient function of the piRNA pathway. Keywords: gene regulation study Overall design: Total small RNA in embryonic and post-birth mouse testes of tdrd1 and tdrd6 mutants
RNF17 blocks promiscuous activity of PIWI proteins in mouse testes.
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View SamplesModern functional genomic approaches may help to better understand the molecular events involved in tissue morphogenesis and to identify molecular signatures and pathways. We have recently applied transcriptomic profiling to evidence molecular signatures in the development of the normal chicken chorioallantoic membrane and in tumor engrafted on the CAM. We have now extended our studies by performing a transcriptome analysis in the wound model of the chicken CAM which is another relevant model of tissue morphogenesis. To induce granulation tissue formation, we performed wounding of the chicken CAM and compared gene expression to normal CAM at the same stage of development. Matched control samples from the same individual were used. We observed a total of 282 genes up-regulated and 44 genes downregulated assuming a false-discovery rate at 5 % and a fold change > 2. Furthermore, bioinformatics analysis lead to the identification of several categories that are associated to organismal injury, tissue morphology, cellular movement, inflammatory disease, development and immune system. Endothelial cell data filtering leads to the identification of several new genes with an endothelial cell signature. In summary, the chick chorioallantoic wound model allows the identification of gene signatures involved in granulation tissue formation and neoangiogenesis. This may constitute a fertile ground for further studies.
Gene signatures in wound tissue as evidenced by molecular profiling in the chick embryo model.
Specimen part
View SamplesMammalian spermatogonial stem cells (SSCs) spontaneously convert to multipotent adult spermatogonial-derived stem cells (MASCs) during in vitro expansion. Here, we examine the epigenetic signature of SSCs and MASCs, identifying bivalent histone H3-lysine4 and -lysine27 trimethylation at somatic gene promoters in SSCs and an ESC-like promoter chromatin state in MASCs. Overall design: Examination of gene expression in different cell types.
Epigenetic profiles signify cell fate plasticity in unipotent spermatogonial stem and progenitor cells.
Specimen part, Cell line, Subject
View SamplesP1 encodes an R2R3-MYB transcription factor responsible for the accumulation of insecticidal flavones in maize silks and red phlobaphene pigments in pericarps and other floral tissues, which contributed to making P1 an important visual marker since the dawn of modern genetics. We conducted RNA-Seq using pericarps at two different stages, 14 and 25 days after pollination (DAP). High-throughput sequencing using the Illumina platform resulted in the generation of ~20 million high quality reads, from which ~90% aligned to the recently completed maize genome sequence corresponding to ~5 million reads for each one of the four samples. Overall design: Examination of two different RNA samples from two different stages of maize pericarp tissues.
A genome-wide regulatory framework identifies maize pericarp color1 controlled genes.
Specimen part, Subject
View SamplesP1 encodes an R2R3-MYB transcription factor responsible for the accumulation of insecticidal flavones in maize silks and red phlobaphene pigments in pericarps and other floral tissues, which contributed to making P1 an important visual marker since the dawn of modern genetics. We conducted RNA-Seq using from maize silks obtained at 2-3 days after emergence. High-throughput sequencing using the Illumina platform resulted in the generation of ~14 million high quality reads, corresponding to ~7 million reads for each sample, from which 76% aligned to the maize genome. Overall design: Examination of two different RNA samples from maize silks obtained at 2-3 days after emergence
A genome-wide regulatory framework identifies maize pericarp color1 controlled genes.
Specimen part, Subject
View SamplesExposure to common environmental chemicals, including those found in personal care products has been linked to mammary cancer at high doses in animal models. Their effects at low doses at levels comparable to human exposure, especially during critical windows of development remain poorly understood. Using a Sprague-Dawley rat model, we investigated the effects of of three environmental chemicals diethyl phthalate (DEP), methyl paraben (MPB) and triclosan (TCS) on the transcriptome of normal developing mammary glands at low doses mimicking human exposure. Rats were exposed during three windows of early development perinatal (gestation day (GD) 1 - 20 or postnatal day (PND) 1 - 20), prepubertal (PND 21 - 41) and pubertal (PND 42 - 62), as well as chronic exposure from birth to end of lactation (PND 1 - 146). Mammary gland whole-transcriptomes were profiled by Affymetrix rat gene 2.0 st arrays.
Changes in mammary histology and transcriptome profiles by low-dose exposure to environmental phenols at critical windows of development.
Sex, Specimen part
View SamplesThere is a lack of systematic investigations of large-scale transcriptome patterns associated with normal breast development. Herein, we profiled whole-transcriptome (by microarrays) of normal mammary glands in female Sprague-Dawley rats, an animal model widely used in breast cancer research, across six distinctive developmental stages pre-pubertal, peri-pubertal, pubertal, lactation, and adult parous and age-matched nulliparous.
Histology and Transcriptome Profiles of the Mammary Gland across Critical Windows of Development in Sprague Dawley Rats.
Sex, Specimen part
View SamplesSynovial fibroblasts in persistent inflammatory arthritis have been suggested to have parallels with cancer growth and wound healing, both of which involve a stereotypical serum response program. We tested the hypothesis that a serum response program can be used to classify diseased tissues, and investigated the serum response program in fibroblasts from multiple anatomical sites and two diseases. To test our hypothesis we utilized a bioinformatics approach to explore a publicly available microarray dataset including RA, OA and normal synovial tissue, then extended those findings in a new microarray dataset representing matched synovial, bone marrow and skin fibroblasts cultured from RA and OA patients undergoing arthroplasty. The classical fibroblast serum response program discretely classified RA, OA and normal synovial tissues. Analysis of low and high serum treated fibroblast microarray data revealed a hierarchy of control, with anatomical site the most powerful classifier followed by response to serum and then disease. In contrast to skin and bone marrow fibroblasts, exposure of synovial fibroblasts to serum led to convergence of RA and OA expression profiles. Pathway analysis revealed three inter-linked gene networks characterising OA synovial fibroblasts: Cell remodelling through insulin-like growth factors, differentiation and angiogenesis through 3 integrin, and regulation of apoptosis through CD44. We have demonstrated that Fibroblast serum response signatures define disease at the tissue level, and that an OA specific, serum dependent repression of genes involved in cell adhesion, extracellular matrix remodelling and apoptosis is a critical discriminator between cultured OA and RA synovial fibroblasts.
Stromal transcriptional profiles reveal hierarchies of anatomical site, serum response and disease and identify disease specific pathways.
Specimen part, Disease
View SamplesHexose-6-phosphate dehydrogenase (H6PD)is the initial component of a pentose phosphate pathway inside the endoplasmic reticulum (ER) that generates NADPH for ER enzymes. In liver, H6PD is required for the 11-oxoreductase activity of 11ss-hydroxysteroid dehydrogenase type 1 (11ss-HSD1), which converts inactive 11-oxo glucocorticoids to their active 11-hydroxyl counterparts; consequently, H6PD null mice are relatively insensitive to glucocorticoids, exhibiting fasting hypoglycemia, increased insulin sensitivity despite elevated circulating levels of corticosterone, and increased basal and insulin-stimulated glucose uptake in muscles normally enriched in Type II (fast) fibers which have increased glycogen content. They also display a progressive vacuolar myopathy evident after 4 weeks of age.
Deletion of hexose-6-phosphate dehydrogenase activates the unfolded protein response pathway and induces skeletal myopathy.
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