BPA disrupts meiosis I in oogonia by acting on pathways including cell cycle regulation, meiosis initiation and spindle assembly

This work was supported by funding to PAF and CC from the Wellcome Trust (080388) and the European Community's Seventh Framework Programme under grant agreement no. 212885. (http://www.abdn.ac.uk/reef/). The authors would like to thank INRAE, SAAJ, experimental animal facility (Sciences de l'Animal et de l'Aliment de Jouy), especially Jean-Pierre Albert, Didier Mauchand, and Jean-François Alkombre.Peer reviewedPublisher PD

Exposure to a Complex Cocktail of Environmental Endocrine-Disrupting Compounds Disturbs the Kisspeptin/GPR54 System in Ovine Hypothalamus and Pituitary Gland

BACKGROUND: Ubiquitous environmental chemicals, including endocrine-disrupting chemicals (EDCs), are associated with declining human reproductive health, as well as an increasing incidence of cancers of the reproductive system. Verifying such links requires animal models exposed to "real-life," environmentally relevant concentrations/mixtures of EDC, particularly in utero, when sensitivity to EDC exposure is maximal. OBJECTIVES: We evaluated the effects of maternal exposure to a pollutant cocktail (sewage sludge) on the ovine fetal reproductive neuroendocrine axes, particularly the kisspeptin (KiSS-1)/GPR54 (G-protein-coupled receptor 54) system. METHODS: KiSS-1, GPR54, and ERalpha (estrogen receptor alpha) mRNA expression was quantified in control (C) and treated (T) maternal and fetal (110-day) hypothalami and pituitary glands using semiquantitative reverse transcription polymerase chain reaction, and colocalization of kisspeptin with LHbeta (luteinizing hormone beta) and ERalpha in C and T fetal pituitary glands quantified using dual-labeling immunohistochemistry. RESULTS: Fetuses exposed in utero to the EDC mixture showed reduced KiSS-1 mRNA expression across three hypothalamic regions examined (rostral, mid, and caudal) and had fewer kisspetin immunopositive cells colocalized with both LHbeta and ERalpha in the pituitary gland. In contrast, treatment had no effect on parameters measured in the adult ewe hypothalamus or pituitary. CONCLUSIONS: This study demonstrates that the developing fetus is sensitive to real-world mixtures of environmental chemicals, which cause significant neuroendocrine alterations. The important role of kisspeptin/GPR54 in regulating puberty and adult reproduction means that in utero disruption of this system is likely to have long-term consequences in adulthood and represents a novel, additional pathway through which environmental chemicals perturb human reproduction

Ovine fetal testis stage-specific sensitivity to environmental chemical mixtures

Acknowledgements We thank George Corsar and Jim MacDonald for the management of experimental animals Funding This work was supported by the European Commission Framework 7 Programme (Contract No 212885)Peer reviewedPublisher PD

Long-term exposure to chemicals in sewage sludge fertilizer alters liver lipid content in females and cancer marker expression in males

This work was supported by the SRF Academic Scholarship Award 2013 (to PAF, PJOS, PF), the Wellcome Trust (080388 to PAF, CC, SMR, RMS, NPE) and the European Community’s Seventh Framework Programme (FP7 ⁄ 2007-2013 to PAF, SMR, CC) under grant agreement no 212885. The authors would like to thank Ms Margaret Fraser and the Proteomics Core Facility at the University of Aberdeen and Ms Carol E. Kyle and as Dr Stewart Rhind (deceased) at James Hutton Institute, Aberdeen, for their important contributions to this study. Supplementary material and research data are available at https://doi.org/10.1016/j.envint.2019.01.003Peer reviewedPublisher PD

Exposure to chemical cocktails before or after conception : The effect of timing on ovarian development

Copyright © 2013 The Authors. Published by Elsevier Ireland Ltd.. All rights reserved.Peer reviewedPublisher PD

Transcriptome profiling of sheep granulosa cells and oocytes during early follicular development obtained by Laser Capture Microdissection

<p>Abstract</p> <p>Background</p> <p>Successful achievement of early folliculogenesis is crucial for female reproductive function. The process is finely regulated by cell-cell interactions and by the coordinated expression of genes in both the oocyte and in granulosa cells. Despite many studies, little is known about the cell-specific gene expression driving early folliculogenesis. The very small size of these follicles and the mixture of types of follicles within the developing ovary make the experimental study of isolated follicular components very difficult.</p> <p>The recently developed laser capture microdissection (LCM) technique coupled with microarray experiments is a promising way to address the molecular profile of pure cell populations. However, one main challenge was to preserve the RNA quality during the isolation of single cells or groups of cells and also to obtain sufficient amounts of RNA.</p> <p>Using a new LCM method, we describe here the separate expression profiles of oocytes and follicular cells during the first stages of sheep folliculogenesis.</p> <p>Results</p> <p>We developed a new tissue fixation protocol ensuring efficient single cell capture and RNA integrity during the microdissection procedure. Enrichment in specific cell types was controlled by qRT-PCR analysis of known genes: six oocyte-specific genes (<it>SOHLH2</it>, <it>MAEL</it>, <it>MATER</it>, <it>VASA</it>, <it>GDF9</it>, <it>BMP15</it>) and three granulosa cell-specific genes (<it>KL</it>, <it>GATA4</it>, <it>AMH</it>).</p> <p>A global gene expression profile for each follicular compartment during early developmental stages was identified here for the first time, using a bovine Affymetrix chip. Most notably, the granulosa cell dataset is unique to date. The comparison of oocyte vs. follicular cell transcriptomes revealed 1050 transcripts specific to the granulosa cell and 759 specific to the oocyte.</p> <p>Functional analyses allowed the characterization of the three main cellular events involved in early folliculogenesis and confirmed the relevance and potential of LCM-derived RNA.</p> <p>Conclusions</p> <p>The ovary is a complex mixture of different cell types. Distinct cell populations need therefore to be analyzed for a better understanding of their potential interactions. LCM and microarray analysis allowed us to identify novel gene expression patterns in follicular cells at different stages and in oocyte populations.</p

Spatio-Temporal Gene Expression Profiling during <i>In Vivo</i> Early Ovarian Folliculogenesis: Integrated Transcriptomic Study and Molecular Signature of Early Follicular Growth

<div><p>Background</p><p>The successful achievement of early ovarian folliculogenesis is important for fertility and reproductive life span. This complex biological process requires the appropriate expression of numerous genes at each developmental stage, in each follicular compartment. Relatively little is known at present about the molecular mechanisms that drive this process, and most gene expression studies have been performed in rodents and without considering the different follicular compartments.</p><p>Results</p><p>We used RNA-seq technology to explore the sheep transcriptome during early ovarian follicular development in the two main compartments: oocytes and granulosa cells. We documented the differential expression of 3,015 genes during this phase and described the gene expression dynamic specific to these compartments. We showed that important steps occurred during primary/secondary transition in sheep. We also described the <i>in vivo</i> molecular course of a number of pathways. In oocytes, these pathways documented the chronology of the acquisition of meiotic competence, migration and cellular organization, while in granulosa cells they concerned adhesion, the formation of cytoplasmic projections and steroid synthesis. This study proposes the involvement in this process of several members of the integrin and BMP families. The expression of genes such as <i>Kruppel-like factor 9</i> (<i>KLF9</i>) and <i>BMP binding endothelial regulator</i> (<i>BMPER</i>) was highlighted for the first time during early follicular development, and their proteins were also predicted to be involved in gene regulation. Finally, we selected a data set of 24 biomarkers that enabled the discrimination of early follicular stages and thus offer a molecular signature of early follicular growth. This set of biomarkers includes known genes such as <i>SPO11 meiotic protein covalently bound to DSB</i> (<i>SPO11</i>), <i>bone morphogenetic protein 15</i> (<i>BMP15</i>) and <i>WEE1 homolog 2</i> (<i>S</i>. <i>pombe</i>)(<i>WEE2</i>) which play critical roles in follicular development but other biomarkers are also likely to play significant roles in this process.</p><p>Conclusions</p><p>To our knowledge, this is the first <i>in vivo</i> spatio-temporal exploration of transcriptomes derived from early follicles in sheep.</p></div

Dynamic representation of gene expression involved in steroid biosynthesis process.

<p>Significant differences in relative gene expression during early folliculogenesis of genes involved in steroid synthesis (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0141482#pone.0141482.s007" target="_blank">S2 Table</a>). *: FDR <0.05, pairwise comparison pval <0.01.</p

Significantly enriched pathways highlighted in early folliculogenesis.

<p>Pathway enrichment analysis for sets of differentially expressed genes during early follicular development was performed using Webgestalt software. Statistical significance was determined by multiple testing correction of p-values using Benjamini-Hochberg test (FDR <0.05). Thirty one enriched pathways are presented. Each graph corresponds to the percentage of gene enrichment in the pathway (%) according to different stages of follicles (PM (primary), SC (secondary) and SA (small antrum)). Granulosa canonical pathways are colored in red and oocyte canonical pathways are colored in blue.</p