An overview of gene expression dynamics during early ovarian folliculogenesis: specificity of follicular compartments and bi-directional dialog

Abstract

BackgroundSuccessful early folliculogenesis is crucial for female reproductive function. It requires appropriate gene specific expression of the different types of ovarian cells at different developmental stages. To date, most gene expression studies on the ovary were conducted in rodents and did not distinguish the type of cell. In mono-ovulating species, few studies have addressed gene expression profiles and mainly concerned human oocytes.ResultsWe used a laser capture microdissection method combined with RNA-seq technology to explore the transcriptome in oocytes and granulosa cells (GCs) during development of the sheep ovarian follicle. We first documented the expression profile of 15 349 genes, then focused on the 5 129 genes showing differential expression between oocytes and GCs. Enriched functional categories such as oocyte meiotic arrest and GC steroid synthesis reflect two distinct cell fates. We identified the implication of GC signal transduction pathways such as SHH, WNT and RHO GTPase. In addition, signaling pathways (VEGF, NOTCH, IGF1, etc.) and GC transzonal projections suggest the existence of complex cell-cell interactions. Finally, we highlighted several transcription regulators and specifically expressed genes that likely play an important role in early folliculogenesis.ConclusionsTo our knowledge, this is the first comprehensive exploration of transcriptomes derived from in vivo oocytes and GCs at key stages in early follicular development in sheep. Collectively, our data advance our understanding of early folliculogenesis in mono-ovulating species and will be a valuable resource for unraveling human ovarian dysfunction such as premature ovarian failure (POF).

Improvement of oocyte in vitro maturation from mice with polycystic ovary syndrome by human mesenchymal stromal cell–conditioned media

“…39,40 This precipitating impact may be related to elevated histone H1 and MAP kinase activities through early stages of maturation. 42,43 We found that a high level of FGF-20 was secreted by MSCs into the CM. 42,43 We found that a high level of FGF-20 was secreted by MSCs into the CM.…”

Transcriptome profile of one-month-old lambs’ granulosa cells after superstimulation

“…Analisis of canonical pathways and regulator effects as well as network analysis were performed as previously described [21]. The activation score (z-score) was used to infer the activation state of transcriptional regulators (z-score<−2 and >2).…”

Transcriptome Landscape Reveals Underlying Mechanisms of Ovarian Cell Fate Differentiation and Primordial Follicle Assembly

“…Despite these results and previous transcriptome analyses performed in rat (Kezele, Ague et al, 2005, Nilsson, Zhang et al, 2013) and mouse fetal and early post-natal ovaries (Bonnet, Cabau et al, 2013, Tan, Zhang et al, 2018), the precise molecular mechanisms underlying oocyte survival/death, granulosa cell differentiation and the crosstalk among them during PF assembly are still incomplete. Moreover, all these studies were performed on entire ovary or follicles so that the contribution of each cell type to the transcriptomes was not distinguishable.…”