title: Glycogen synthase kinase 3B in bovine oocytes and granulosa cells: possible involvement in meiosis during in vitro maturation.
abstract: Glycogen synthase kinase 3 (GSK3) regulates cellular metabolism and cell cycle via different signalling pathways. In response to insulin and growth factors GSK3 is serine-phosphorylated and inactivated. We analysed GSK3B expression and activation in bovine cumulus cells (CC) and oocytes at different meiotic stages in vitro in parallel with MAP kinases ERK (MAPK3/MAPK1) and p38 (MAPK14). GSK3B localised to cytoplasm in granulosa cells and in oocytes throughout folliculogenesis. In mature metaphase-II (MII) oocytes, GSK3B was concentrated to the region of midzone between the oocyte and the first polar body, as well as active phospho-Thr Aurora A kinase (AURKA). During in vitro maturation (IVM), in oocytes, phospho-Ser(9)-GSK3B level increased as well as phospho-MAPK3/MAPK1, while phospho-MAPK14 decreased. In CC, phospho-MAPK14 increased upon germinal vesicle breakdown (GVBD)/metaphase-I (MI) and then decreased during transition to MII. Administration of inhibitors of GSK3 activity (lithium chloride or 2'Z,3'E -6-bromoindirubin-3'-oxime) rapidly increased phospho-Ser(9)-GSK3B, and led to transient decrease of phospho-MAPK3/MAPK1 and to durable enhancing of phospho-MAPK14 in granulosa primary cell culture. GSK3 inhibitors during IVM diminished cumulus expansion and delayed meiotic progression. In cumulus, phospho-MAPK14 level was significantly higher in the presence of inhibitors, comparing with control, through the time of MI/MII transition. In oocytes, phospho-GSK3B was increased and phospho-MAPK3/MAPK1 was decreased before GVBD and oocytes were mainly arrested at MI. Therefore, GSK3B might regulate oocyte meiosis, notably MI/MII transition being the part of MAPK3/1 and MAPK14 pathways in oocytes and CC. GSK3B might be also involved in the local activation of AURKA that controls this transition.
authors.affiliation: Physiologie de la Reproduction et des Comportements, UMR6175 INRA, CNRS, Université de Tours, Haras Nationaux, Nouzilly, France. svetlana.uzbekova@tours.inra.fr
authors.forename: Svetlana
authors.initials: S
authors.lastname: Uzbekova
authors.forename: Mohamad
authors.initials: M
authors.lastname: Salhab
authors.forename: Christine
authors.initials: C
authors.lastname: Perreau
authors.forename: Pascal
authors.initials: P
authors.lastname: Mermillod
authors.forename: Joëlle
authors.initials: J
authors.lastname: Dupont
mesh_terms: D000818:Animals; D064127:Aurora Kinases; D002417:Cattle / Q000378:metabolism*; D002478:Cells, Cultured; D003593:Cytoplasm / Q000201:enzymology; D004789:Enzyme Activation; D005260:Female; D005307:Fertilization in Vitro; D038362:Glycogen Synthase Kinase 3 / Q000032:analysis / Q000378:metabolism*; D006107:Granulosa Cells / Q000201:enzymology*; D007150:Immunohistochemistry; D008540:Meiosis / Q000502:physiology*; D019950:Mitogen-Activated Protein Kinase 1 / Q000032:analysis / Q000378:metabolism; D048308:Mitogen-Activated Protein Kinase 14 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000032:analysis / Q000378:metabolism; D020929:Mitogen-Activated Protein Kinase Kinases / Q000032:analysis / Q000378:metabolism; D009865:Oocytes / Q000166:cytology / Q000201:enzymology*; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000032:analysis / Q000378:metabolism
chemical_list: D064127:Aurora Kinases; D017346:Protein Serine-Threonine Kinases; D019950:Mitogen-Activated Protein Kinase 1; D048308:Mitogen-Activated Protein Kinase 14; D048052:Mitogen-Activated Protein Kinase 3; D038362:Glycogen Synthase Kinase 3; D020929:Mitogen-Activated Protein Kinase Kinases