Expression data from mouse oocytes treated with low-dose bisphenol S
Ontology highlight
ABSTRACT: Bisphenol S (BPS) is widely used to replace earlier-eliminated BPA. We evaluated the effect of acute in vivo BPS exposure on oocyte quality using eight-weeks-old ICR female mice (N = 15 per experimental group), exposed to vehicle or BPS1-BPS4 (0.001, 0.1, 10, and 100 ng BPS x g bw-1 x day-1, respectively). Oocytes were isolated and matured in vitro. Thereafter, we observed that BPS exposure increases aberrant spindle formation in mature oocytes and induces DNA damage. Moreover, BPS3 significantly increases chromatin repressive marks 5-methyl cytosine (5meC) and H3K27me2 in immature oocytes. In the BPS2 group (0.1 ng x g bw-1 x day-1), the increase in 5meC arises during oocyte maturation. Transcriptome analysis shows differential expression of early embryonic development transcripts in BPS2-exposed oocytes. These findings indicate that the biological effect of BPS is non-monotonic, affecting oocyte quality even at concentrations that are orders of magnitude below those measured in humans. We used microarray aproach to unravel gene expression differences triggered by the administration of BPS at different concentrations in mouse oocytes.
Project description:Lactating cows experience transient metabolic stresses during postpartum which results in abnormal concentrations of non-esterified fatty acids and beta-hydroxybutyrate that can impact oocyte maturation and ultimately reproductive success. We hypothesize that metabolic challenges in lactating cows influence DNA methylation changes of the oocyte affecting genes involved in oocyte developmental competency. Therefore, we compared whole genome bisultfite sequencing (wgbs) of the oocytes collected from 5-6 week (early) or 9-10 week (mid) post-partum against that of oocytes from nulliparous heifers as metabolically unchallenged condition control. Bisulfite-Seq DNA libraries were generated from pooled oocytes using an EZ DNA methylation-direct kit and Pico-Methyl seq library preparation kit (Zymo Research), and parallel sequenced using the illumina HiSeq2500 system.
Project description:We optimised an in vitro culture model for mouse oocytes starting from immature oocytes to get mature oocytes and investigated the effect of oxygen concentrations on the cultured oocytes (5 % vs 20% oxygen). The cultured oocytes were size-selected in both conditions. We generated expression and methylation profiling (RNA-Seq, RRBS, PBAT) by high throughput sequencing from these size selected oocytes and compared the results with in vivo size oocytes. Our observations reveal changes in DNA methylation and transcripts between oocytes cultured in vitro with different oxygen concentrations and in vivo grown murine oocytes. Oocytes grown under 20% O2 had a higher correlation with in vivo oocytes for DNA methylation and transcription demonstrating that higher oxygen concentration is beneficial for the oocyte maturation in ex-vivo culture condition.
Project description:The genetic causes of oocyte meiotic deficiency (OMD), a form of primary infertility characterised by the production of immature oocytes, remain largely unexplored. Using whole exome sequencing, we found that 26% of a cohort of 23 subjects with OMD harboured the same homozygous nonsense pathogenic mutation in PATL2, a gene encoding a putative RNA-binding protein. Using Patl2 knockout mice, we confirmed that PATL2 deficiency disturbs oocyte maturation, since oocytes and zygotes exhibit morphological and developmental defects respectively. PATL2's amphibian orthologue is involved in the regulation of oocyte mRNA as a partner of CPEB. However, Patl2's expression profile throughout oocyte development in mice, alongside colocalisation experiments with Cpeb1, Msy2 and Ddx6 (three oocyte RNA-regulators) suggest an original role for Patl2 in Mammals. Accordingly, transcriptomic analysis of oocytes from WT and Patl2-/- animals demonstrated that in the absence of Patl2, expression levels of a select number of highly relevant genes involved in oocyte maturation and early embryonic development are deregulated. In conclusion, PATL2 is a novel actor of mammalian oocyte maturation whose invalidation causes OMD in humans.
Project description:The mechanisms of aging-related oocyte aneuploidy remain elusive. Hi-C and SMART-seq revealed aging-related decreases in chromosome condensation, particularly for genomic regions proximal to the centromeres, accompanied with disrupted meiosis-associated gene expression in metaphase I (MI) aged oocytes. Further transcriptomic analysis showed that oocyte meiotic maturation was correlated with robust increases in mevalonate (MVA) pathway gene expression in young oocyte-surrounding granulosa cells (GCs), which was largely downregulated in aged GCs. Inhibtion of MVA metabolism in GCs by statins resulted in marked meiotic defects and aneuploidy in young cumulus-oocyte complexes (COCs). Conversely, supplementation with the MVA isoprenoid geranylgeraniol ameliorated meiotic defects and aneuploidy in aged COCs. Meanwhile, geranylgeraniol also activated LHR/EGF signaling in aged GCs and then enhanced the meiosis-associated gene expression in oocytes. Generally, the MVA pathway in GCs is a critical regulator of meiotic maturation and euploidy in oocytes.
Project description:Study Question: What effects do maternal age and oocyte maturation stage have on the human oocyte transcriptome that may be associated with oocyte developmental potential? Summary Answer: Although polyadenylated transcript abundance changes during human oocyte maturation irrespective of age, young (YNG) and advanced maternal age (AMA) metaphase II (MII) oocytes exhibit divergent transcriptomes. What is known already: Maternal age and maturation stage affect oocyte polyadenylated transcript abundance in human oocytes. Although RNA-Seq analysis of single human MII oocytes has been conducted, comparison of the germinal vesicle (GV) and MII oocyte transcriptomes has not been investigated using RNA-Seq, a technique that could provide novel insight into oocyte maturation and age-associated aberrations in gene expression. Participants / materials, settings, methods: Patients undergoing infertility treatment at the Colorado Center for Reproductive Medicine (Lone Tree, CO, USA) underwent ovarian stimulation with FSH and received hCG for final follicular maturation prior to ultrasound guided egg retrieval. Unused GV oocytes obtained at retrieval were donated for transcriptome analysis. Single oocytes were stored (at -80°C in PicoPure RNA Extraction Buffer; Thermo Fisher Scientific, USA) immediately upon verification of immaturity or after undergoing in vitro oocyte maturation (24 hour incubation), representing GV and MII samples, respectively. After isolating RNA and generating single oocyte RNA-Seq libraries (SMARTer Ultra Low Input RNA HV kit; Clontech, USA), Illumina sequencing (100 bp paired-end reads in HiSeq 2500) and bioinformatics analysis (CLC Genomics Workbench, DESeq2, Weighted Gene Correlation Network Analysis (WGCNA), 3’UTR motif analysis, Ingenuity Pathway Analysis) were performed. Main results and the role of chance: Within the 12,770 expressed genes in human oocytes (reads per kilobase per million mapped reads (RPKM) > 0.4 in at least 3 of 5 replicates for a minimum of one sample type), 458 and 3,506 genes significantly (adjusted p < 0.05 and log2 fold change > 1) increased and decreased in polyadenylated transcript abundance during oocyte maturation, respectively. The differentially expressed genes were enriched (FDR < 0.05) for biological functions and canonical pathways related to cell cycle and mitochondrial function. The majority (76%) and minority (25%) of up- and down-regulated transcripts with a complete 3’UTR were predicted to be targets of cytoplasmic polyadenylation (910 total genes), respectively. Differential gene expression analysis between young and advanced maternal age oocytes (within stage) identified 1 and 255 genes that significantly differed (adjusted p < 0.1 and log2 fold change > 1) in polyadenylated transcript abundance for GV and MII oocytes, respectively. These genes included CDK1, NLRP5, and PRDX1, which have been reported to affect oocyte developmental potential and be markers of oocyte quality. Despite similarity in transcript abundance between GV oocytes irrespective of age, divergent expression patterns emerged during oocyte maturation. These age-specific differentially expressed genes were enriched (FDR < 0.05) for functions and pathways associated with mitochondria, cell cycle, and cytoskeleton. Gene modules generated by WGCNA (based on gene expression) and patient traits related to oocyte quality (e.g. age and blastocyst development) were determined to be correlated (p < 0.05) and enriched (FDR < 0.05) for functions and pathways associated with oocyte maturation. Limitations, reasons for caution: The human oocytes used in the current study were obtained from patients with varying causes of infertility (e.g. decreased oocyte quality and oocyte quality-independent factors), possibly affecting oocyte gene expression. Oocytes in this study were retrieved at the GV stage following hCG administration and the MII oocytes were derived by in vitro maturation of patient oocytes, which has the benefit of identifying intrinsic differences between samples, but may not be completely representative of in vivo matured oocytes. Thus, these factors should be considered when interpreting the results. Wider Implications of the findings: Transcriptome profiles of young and advanced maternal age oocytes, particularly at the MII stage, suggest aberrant transcript abundance contributes to the age-associated decline in fertility.
Project description:Maternal RNAs are stored from minutes to decades in oocytes throughout meiotic arrest. The nature and dynamics of maternal RNAs during this arrest remain uncharted. We address this by performing single-oocyte RNA sequencing on arrested and maturing C. elegans oocytes. We discovered a population of transcripts that increases as the arrested meiosis I oocyte ages, but ruled out ERK signaling and nascent transcription as a mechanism for this increase. Instead, we report extracellular communication from neighboring somatic cells as a mechanism for the increase in transcripts during meiosis I arrest. These analyses provide a single-cell resolution of the RNA landscape during the developmental history of a meiosis I arrested oocyte and as it prepares for oocyte maturation and embryonic progression.
Project description:Mono(2-ethylhexyl) phthalate (MEHP), the main di(2-ethylhexyl) phthalate (DEHP) metabolite, is a known reproductive toxicant. Residual levels of 20 nM MEHP have been found in follicular fluid aspirated from IVF-treated women and DEHP-treated animals. It is not yet clear whether these residual MEHP levels have any effect on the follicle-enclosed oocyte or developing embryo. To clarify this point, bovine oocytes were matured with or without 20 nM MEHP for 22 h. Microarray analysis was performed for both mature oocytes and 7-day blastocysts. A feasibility examination was performed on mature oocytes (n = 200/group) to reveal a possible direct effect on the oocyte proteomic profile. Transcriptome analysis revealed MEHP-induced alterations in the expression of 456 and 290 genes in oocytes and blastocysts, respectively. The differentially expressed genes are known to be involved in various biological pathways, such as transcription process, cytoskeleton regulation and metabolic pathway. Among these, the expression of 9 genes was impaired in both oocytes exposed to MEHP (i.e., direct effect) and blastocysts developed from those oocytes (i.e., carryover effect). In addition, 191 proteins were found to be affected by MEHP in mature oocytes. The study explores, for the first time, the risk associated with exposing oocytes to physiologically relevant MEHP concentrations to the maternal transcripts. Although it was the oocytes that were exposed to MEHP, alterations carried over to the blastocyst stage, following embryonic genome activation, implying that these embryos are of low quality.
Project description:We analyzed the functions of BTG family proteins in maternal mRNA degradation in mouse oocytes. By comparing the degradation of transcripts in WT oocytes and KO oocytes, we are able to know the defects in maternal mRNA clearance in BTG4-deleted oocytes, and identified the BTG4 target genes in oocyte cyplasmic maturation. 2 WT oocyte samples at GV stage, 2 WT oocyte samples at MII stage, 2 Btg4-/- oocyte samples at GV stage and 2 Btg4-/- oocyte samples at MII stage?2 WT embryo samples at zygote stage, 2 WT embryo samples at 2-cell stage, 2 Btg4-/- embryo samples at zygote stage and 2 Btg4-/- embryo samples at 2-cell stage , and a WT GV oocyte, a WT MII oocyte, a Erk-/- GV oocyte and a Erk-/- MII oocyte are performed RNA sequencing.
Project description:Follicle stimulating hormone (FSH) and epidermal growth factor (EGF) are currently used on cumulus-oocyte complexes to mimic the luteinizing hormone surge in vitro and induce oocyte maturation and cumulus expansion. We have previously shown that addition of exogenous recombinant growth differentiation factor 9 (GDF9) during oocyte in vitro maturation led to an improvement of oocyte quality, as shown by an increased blastocyst percentage and fetal survival. Our objective was to characterize the effect of FSH/EGF and GDF9 treatments on mouse cumulus cells expression profile by microarray analysis. Cumulus-oocyte complexes (COCs) were recovered from 21 to 26 day old female 129/SV mice, 44 hours post equine chorionic gonadotropin treatment (eCG (5 IU)). For the microarray experiment whole COCs were treated with 293H control medium (0.125% v/v), with 20 ng/ml GDF9 or with a combination of 50 mIU/ml FSH and 10 ng/ml EGF. After 8 hours of in vitro maturation, COCs were denuded by gentle pipetting, the oocytes were removed and the cumulus cells centrifuged and extracted RNA analysed by microarray.