title: Characterization of FSH signalling networks in bovine cumulus cells: a perspective on oocyte competence acquisition.
abstract: Understanding the mechanisms regulating oocyte developmental competence is essential to enhance the clinical efficiency of assisted reproduction. FSH orchestrates the acquisition of oocyte competence, both in vivo and in vitro. Multiple pathways are implicated in FSH signalling; however, their precise coordination remains unresolved. A robust system to investigate FSH signalling is oocyte in vitro maturation (IVM) and we have previously demonstrated better bovine embryo development after FSH addition for the first 6 h during IVM. Using this model, we investigated FSH signalling in cumulus through transcriptomic and pharmacological tools. We demonstrate modulation of cumulus transcriptome by FSH mainly through protein kinase A (PKA) and epidermal growth factor (EGF) pathways. Differentially expressed transcripts were implicated in cumulus expansion, steroidogenesis, cell metabolism and oocyte competence. FSH required rouse-sarcoma oncogene (SRC) for EGF receptor transactivation. PKA and EGF pathway crosstalk was investigated using extracellular signal-regulated kinases (ERK1/2) phosphorylation as the functional end-point. FSH enhanced ERK1/2 activation by the EGF pathway with a simultaneous diminution through PKA. More specifically, FSH increased dual specific phosphatase (DUSP1) transcripts via PKA although DUSP1 protein did not change since EGF was required to prevent degradation. Our findings implicate FSH in PKA and EGF pathway activation, which interact to maintain appropriate levels of ERK1/2 phosphorylation and eventually cumulus expansion, metabolism and steroidogenesis. Moreover, considering the implication of the EGF pathway in GDF9 and BMP15 actions, our findings suggest that FSH may have a role in modulation of the cumulus response to oocyte-secreted factors. This information has implications for improvement of IVM and hence oocyte developmental competence.
authors.affiliation: Centre de Recherche en Biologie de la Reproduction, Département des Sciences Animales, Faculté des sciences de l'agriculture et de l'alimentation, Université Laval, Québec, Canada.
authors.forename: D R
authors.initials: DR
authors.lastname: Khan
authors.affiliation: Centre de Recherche en Biologie de la Reproduction, Département des Sciences Animales, Faculté des sciences de l'agriculture et de l'alimentation, Université Laval, Québec, Canada.
authors.forename: C
authors.initials: C
authors.lastname: Guillemette
authors.affiliation: Centre de Recherche en Biologie de la Reproduction, Département des Sciences Animales, Faculté des sciences de l'agriculture et de l'alimentation, Université Laval, Québec, Canada.
authors.forename: M A
authors.initials: MA
authors.lastname: Sirard
authors.affiliation: Centre de Recherche en Biologie de la Reproduction, Département des Sciences Animales, Faculté des sciences de l'agriculture et de l'alimentation, Université Laval, Québec, Canada francois.richard@fsaa.ulaval.ca.
authors.forename: F J
authors.initials: FJ
authors.lastname: Richard
mesh_terms: D000818:Animals; D002417:Cattle; D019295:Computational Biology; D054885:Cumulus Cells / Q000187:drug effects* / Q000378:metabolism; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism; D054638:Dual Specificity Phosphatase 1 / Q000378:metabolism; D004815:Epidermal Growth Factor / Q000378:metabolism; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D005260:Female; D005299:Fertility Agents / Q000494:pharmacology*; D005640:Follicle Stimulating Hormone / Q000494:pharmacology*; D020869:Gene Expression Profiling; D018507:Gene Expression Regulation, Developmental; D053263:Gene Regulatory Networks; D059471:In Vitro Oocyte Maturation Techniques; D009865:Oocytes / Q000187:drug effects* / Q000378:metabolism; D010766:Phosphorylation; D012333:RNA, Messenger / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects* / Q000235:genetics; D013997:Time Factors; D059467:Transcriptome
chemical_list: D005299:Fertility Agents; D012333:RNA, Messenger; D004815:Epidermal Growth Factor; D005640:Follicle Stimulating Hormone; D017868:Cyclic AMP-Dependent Protein Kinases; D048049:Extracellular Signal-Regulated MAP Kinases; D054638:Dual Specificity Phosphatase 1
keywords: FSH; cumulus cells; epidermal growth factor; extracellular signal-regulated kinases; in vitro maturation; oocyte maturation; protein kinase A; transcriptomics