title: Disruption of bidirectional oocyte-cumulus paracrine signaling during in vitro maturation reduces subsequent mouse oocyte developmental competence.
abstract: Oocyte-cumulus cell bidirectional communication is essential for normal development of the oocyte and cumulus cells (CCs) within the follicle. We showed recently that addition of recombinant growth differentiation factor 9 (GDF9), which signals through the SMAD2/3 pathway, during mouse oocyte in vitro maturation (IVM) increased fetal viability. This study thus aimed to observe the effects of disrupting oocyte-CC bidirectional communication during IVM on oocyte developmental competence and fetal outcomes. Cumulus-oocyte complexes (COCs) from equine chorionic gonadotropin-primed prepubertal (CBA/C57BL6) mice were cultured with or without 50 mIU/ml follicle-stimulating hormone (FSH) and 10 ng/ml epidermal growth factor (EGF) or 4 muM SMAD2/3 inhibitor SB-431542. Cumulus expansion and first polar body extrusion were then assessed, or COCs were fertilized and stained to evaluate sperm entry or cultured to the blastocyst stage. Embryo development and blastocyst quality were assessed, and Day 4.5 blastocysts were transferred to pseudopregnant recipients to analyze fetal outcomes. SMAD2/3 inhibition or FSH/EGF absence during IVM resulted in decreased cumulus expansion. First polar body extrusion and sperm entry were decreased in the absence of FSH/EGF, whereas only sperm entry was affected in SB-431542-matured COCs. Embryo development and blastocyst rates were unaffected; however, blastocyst quality was significantly altered, with reduced inner cell mass cell numbers in embryos derived from COCs matured in both treatments. When COCs were matured with SB-431542 in the absence of FSH/EGF, cumulus expansion was reduced, but fertilization, embryo development, and embryo quality were not. Inhibition of SMAD2/3 signaling in the presence of FSH/EGF significantly reduced fetal survival but had no effect on implantation or fetal and placental dimensions and morphology.
authors.affiliation: Research Centre for Reproductive Health, University of Adelaide, Adelaide, South Australia, Australia.
authors.forename: Christine X
authors.initials: CX
authors.lastname: Yeo
authors.forename: Robert B
authors.initials: RB
authors.lastname: Gilchrist
authors.forename: Michelle
authors.initials: M
authors.lastname: Lane
mesh_terms: D000818:Animals; D001549:Benzamides / Q000494:pharmacology; D001755:Blastocyst / Q000166:cytology / Q000187:drug effects; D002452:Cell Count; D054885:Cumulus Cells / Q000187:drug effects / Q000502:physiology*; D004149:Dioxoles / Q000494:pharmacology; D047108:Embryonic Development / Q000187:drug effects; D004815:Epidermal Growth Factor / Q000494:pharmacology; D005260:Female; D005640:Follicle Stimulating Hormone / Q000494:pharmacology; D055429:Growth Differentiation Factor 9 / Q000494:pharmacology; D066298:In Vitro Techniques; D051379:Mice; D008810:Mice, Inbred C57BL; D008808:Mice, Inbred CBA; D009865:Oocytes / Q000187:drug effects / Q000254:growth & development* / Q000502:physiology*; D019899:Paracrine Communication / Q000187:drug effects; D011247:Pregnancy; D011256:Pregnancy Outcome; D011994:Recombinant Proteins / Q000494:pharmacology; D051899:Smad2 Protein / Q000037:antagonists & inhibitors / Q000378:metabolism; D051900:Smad3 Protein / Q000037:antagonists & inhibitors / Q000378:metabolism; D013084:Sperm-Ovum Interactions / Q000187:drug effects
chemical_list: C459179:4-(5-benzo(1,3)dioxol-5-yl-4-pyridin-2-yl-1H-imidazol-2-yl)benzamide; D001549:Benzamides; D004149:Dioxoles; C525898:Gdf9 protein, mouse; D055429:Growth Differentiation Factor 9; D011994:Recombinant Proteins; D051899:Smad2 Protein; C497783:Smad2 protein, mouse; D051900:Smad3 Protein; C497791:Smad3 protein, mouse; D004815:Epidermal Growth Factor; D005640:Follicle Stimulating Hormone