Project description:Determining the spatial and temporal expression of genes involved in the ovulatory pathway is critical for the understanding of the role of each estrogen receptor in the modulation of folliculogenesis and ovulation. Estrogen receptor (ER) b is highly expressed in ovarian granulosa cells and mice lacking ERb (bERKO) are subfertile due to inefficient ovulation. Previous work has focused on isolated granulosa cells or cultured follicles and while informative, provides confounding results due to the heterogeneous cell types present including granulosa, theca and oocytes and exposure to in vitro conditions. Herein, we isolated preovulatory granulosa cells from WT and ERb-null mice using laser capture microdissection to examine the genomic transcriptional response downstream of PMSG (mimicking FSH) and PMSG/hCG (mimicking LH) stimulation. This allows for a direct comparison of in vivo granulosa cells at the same stage of development from both WT and ERb-null ovaries. ERb-null granulosa cells showed altered expression of genes known to be regulated by FSH (Akap12 and Runx2) as well as not previously reported (Arnt2 and Pou5f1) in WT granulosa cells. Our analysis also identified 304 genes not previously associated with ERb in granulosa cells. LH responsive genes including Abcb1b and Fam110c show reduced expression in ERb-null granulosa cells; however novel genes including Rassf2 and Megf10 were also identified as being downstream of LH signaling in granulosa cells. Collectively, our data suggests that granulosa cells from ERb-null ovaries may not be appropriately differentiated and are unable to respond properly to gonadotropin stimulation We used microarray to compare the gene expression profiles of wiltype (WT) and Erb-null (bERKO) preovulatory granulosa cells as they respond to either PMSG or PMSG+hCG treatments. Laser microdissection was used to collect a purified population of granulosa cells only from preovulatory follicles. We chose to compre the response to PMSG or PMSG+hCG of granulosa cells collected from either WT and bERKO preovulatory follicles. We chose to collect cells 48h after mice were treated with PMSG to compare the gene expression profile ot preovulatory granulosa cells. We also studied the response of these cells to LH (or hCG) as we collected cells 4h after mice were treated with hCG (peak of transcriptional response to hCG).

Project description:Female infertility syndromes are among the most prevalent chronic health disorders in women, but their molecular basis remains unknown because of the complexity of oogenesis and uncertainty regarding the number and identity of ovarian factors controlling the assembly, preservation, and maturation of ovarian follicles. To systematically discover such ovarian fertility factors en masse, we employed a mouse model (Foxo3), where follicles are assembled normally but are then synchronously activated. Gene expression profiling of mutant and normal ovaries led to the identification a surprisingly large set of ovarian factors. The set included the vast majority of known ovarian factors, many of which when mutated produce female sterility phenotypes, but most were novel. Subsequent analyses revealed novel classes of ovarian factors and significant overrpresentation on the X chromosome, among other insights into the general properties of oogenesis genes and their patterns of expression. Experiment Overall Design: Total ovarian RNA from +/+ and -/- ovaries at PND1, 3, 7, and 14 (n=3 replicates per timepoint and genotype, a total of 24 microarrays) was subjected to linear RNA amplification and hybridized to Affymetrix 430 2.0 mouse whole-genome microarrays, which interrogate >39K transcripts including the vast majority of protein-coding genes. We also profiled 14 somatic tissues. Additionally, to provide more refined views of gene expression, we profiled adult ovaries, adult testis, KitlSl/KitlSl-d testis (devoid of germ cells except for rare spermatogonia) (Shinohara et al., 2000), ES cells, laser-capture microdissected (LCM) primary oocytes, LCM somatic cells (granulosa cells + surrounding stroma), superovulated unfertilized eggs, cumulus granulosa cells, and E11 Foxo3 +/+ and -/- embryos. Each array data set was independently normalized by global median scaling, and the signal strengths were averaged for those samples for which replicates were available (PND1-14).

Project description:Background Correct achievement of early ovarian folliculogenesis is a crucial phase for further ovarian function. This process is closely regulated by cell-cell interactions and coordinated expression of genes from oocyte and granulosa cells. But, despite of the large number of studies, little is known about the precise gene expression patterns driving early folliculogenesis. The experimental limitations concerned the very small size of these follicles and the mixture of the different developmental stages within an ovary that make the study of isolated follicular components much more difficult. The recently developed laser capture microdissection (LCM) technique coupled with microarrays experiments is promising in addressing the molecular specificity of each follicular compartment. Nevertheless, the isolation of unique cells or group of cells is still challenging to maintain RNA quality during this process and to obtain sufficient amount of RNA. In this study, we described a method allowing the analysis of oocyte and granulosa cells gene expression during the first stages of sheep early folliculogenesis. Results First we developed a new fixation protocol using a frizzed 70% ethanol fixation solution that ensures correct single cell capture and RNA integrity during microdissection time. After LCM capture of the compartments and follicular stages, RNA extraction and amplification, the expression of 6 oocyte-specific genes (SOHLH2, MAEL, MATER, VASA, GDF9, BMP15) and 3 granulosa cell-specific genes (KITLG, GATA4, AMH) confirmed the purity of the samples and documented their ovine expression profiles. Then, using bovine Affymetrix chip, we identified for the first time, a global gene expression for each follicular compartment during early developmental stages. Particularly the granulosa cell data set is quite unique. 1050 granulosa cell specific transcripts compared to oocyte and 759 oocyte specific transcripts were detected. The analysis of the expression of 2 genes (SIRT7, FST) confirmed this specificity of expression. Finally, the integration of the data stated the 3 main physiological events involved in early folliculogenesis and provided descriptive elements that confirmed the relevance and the potential of the LCM-derived RNAs. Conclusions This method should contribute through an additional genome wide expression profiling to give insights on molecular mechanisms involved in stage transitions and cell type interplays.

Dataset Information

E-GEOD-44651

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure