title: Progesterone regulation of AVEN protects bovine oocytes from apoptosis during meiotic maturation.
abstract: Inhibition of progesterone (P4) synthesis by cumulus cells during bovine in vitro oocyte maturation (IVM) causes a decrease in subsequent embryo development, indicating that P4 intracellular signaling within the cumulus oocyte complex (COC) is important for oocyte developmental competence. The aim of the present study was to further elucidate, on a protein level, the downstream signaling pathway involved in P4 regulation of oocyte developmental competence. COCs were subjected to IVM for 24 h in the presence or absence of trilostane, aglepristone, or promegestone (R5020). These altered IVM conditions resulted in dynamic changes in protein expression of the progesterone receptors and the cell death-regulated proteins AVEN, BCL-xL, and active caspase 3. In addition, AVEN protein localization, caspase 3 activation, and mitochondrial distribution were studied by immunofluorescence. Inhibition of progesterone synthesis (trilostane treatment) resulted in changes in AVEN localization within the COC, corresponding to caspase 3 activation and altered mitochondrial distribution. AVEN was also found to bind BCL-xL in COCs, but this interaction was lost following treatment with trilostane.
authors.affiliation: School of Biomolecular and Biomedical Science, Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin, Ireland.
authors.forename: Lynne C
authors.initials: LC
authors.lastname: O'Shea
authors.forename: Carmel
authors.initials: C
authors.lastname: Hensey
authors.forename: Trudee
authors.initials: T
authors.lastname: Fair
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D017209:Apoptosis / Q000187:drug effects / Q000235:genetics; D051017:Apoptosis Regulatory Proteins / Q000235:genetics* / Q000378:metabolism; D002417:Cattle; D002478:Cells, Cultured; D005260:Female; D005786:Gene Expression Regulation; D059471:In Vitro Oocyte Maturation Techniques / Q000662:veterinary; D008540:Meiosis / Q000187:drug effects / Q000235:genetics; D008928:Mitochondria / Q000502:physiology; D008969:Molecular Sequence Data; D009865:Oocytes / Q000187:drug effects* / Q000502:physiology; D009866:Oogenesis / Q000187:drug effects / Q000235:genetics; D011374:Progesterone / Q000494:pharmacology*; D017386:Sequence Homology, Amino Acid
chemical_list: D051017:Apoptosis Regulatory Proteins; D011374:Progesterone
keywords: apoptosis; cow; developmental competence; egg quality; in vitro maturation; progesterone receptors