title: The effect of lysophosphatidic acid during in vitro maturation of bovine cumulus-oocyte complexes: cumulus expansion, glucose metabolism and expression of genes involved in the ovulatory cascade, oocyte and blastocyst competence.
abstract: BACKGROUND
  In the cow, lysophosphatidic acid (LPA) acts as an auto-/paracrine factor, through its receptors LPAR1-4, on oocytes and cumulus cells during in vitro maturation (IVM). The aim of the present work was to determine the effect of LPA during IVM of bovine oocytes on: 1) oocyte maturation; 2) apoptosis of COCs; 3) expression of genes involved in developmental competence and apoptosis in bovine oocytes and subsequent blastocysts; 4) cumulus expansion and expression of genes involved in the ovulatory cascade in cumulus cells; 5) glucose metabolism and expression of genes involved in glucose utilization in cumulus cells; 6) cleavage and blastocyst rates on Day 2 and Day 7 of in vitro culture, respectively.
  
  
  METHODS
  Cumulus-oocyte complexes (COCs) were matured in vitro in the presence or absence of LPA (10(-5) M) for 24 h. Following maturation, we determined: oocyte maturation stage, cumulus expansion, COCs apoptosis and glucose and lactate levels in the maturation medium. Moreover, COCs were either used for gene expression analysis or fertilized in vitro. The embryos were cultured until Day 7 to assess cleavage and blastocyst rates. Oocytes, cumulus cells and blastocysts were used for gene expression analysis.
  
  
  RESULTS
  Supplementation of the maturation medium with LPA enhanced oocyte maturation rates and stimulated the expression of developmental competence-related factors (OCT4, SOX2, IGF2R) in oocytes and subsequent blastocysts. Moreover, LPA reduced the occurrence of apoptosis in COCs and promoted an antiapoptotic balance in the transcription of genes involved in apoptosis (BAX and BCL2) either in oocytes or blastocysts. LPA increased glucose uptake by COCs via augmentation of GLUT1 expression in cumulus cells as well as stimulating lactate production via the enhancement of PFKP expression in cumulus cells. LPA did not affect cumulus expansion as visually assessed, however, it stimulated upstream genes of cumulus expansion cascade, AREG and EREG.
  
  
  CONCLUSIONS
  Supplementation of the maturation medium with LPA improves oocyte maturation rates, decreases extent of apoptosis in COCs and sustains the expression of developmental competence related factors during oocyte maturation and subsequently affects gene expression profile at the blastocyst stage. We also demonstrate that LPA directs glucose metabolism toward the glycolytic pathway during IVM.
authors.affiliation: Department of Reproductive Immunology and Pathology, Institute of Animal Reproduction and Food Research, Polish Academy of Sciences, Tuwima 10, 10-748, Olsztyn, Poland. d.boruszewska@pan.olsztyn.pl.
authors.forename: Dorota
authors.initials: D
authors.lastname: Boruszewska
authors.affiliation: Department of Reproductive Immunology and Pathology, Institute of Animal Reproduction and Food Research, Polish Academy of Sciences, Tuwima 10, 10-748, Olsztyn, Poland. e.sinderewicz@pan.olsztyn.pl.
authors.forename: Emilia
authors.initials: E
authors.lastname: Sinderewicz
authors.affiliation: Department of Reproductive Immunology and Pathology, Institute of Animal Reproduction and Food Research, Polish Academy of Sciences, Tuwima 10, 10-748, Olsztyn, Poland. i.kowalczyk@pan.olsztyn.pl.
authors.forename: Ilona
authors.initials: I
authors.lastname: Kowalczyk-Zieba
authors.affiliation: Department of Reproductive Immunology and Pathology, Institute of Animal Reproduction and Food Research, Polish Academy of Sciences, Tuwima 10, 10-748, Olsztyn, Poland. k.grycmacher@pan.olsztyn.pl.
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Grycmacher
authors.affiliation: Department of Reproductive Immunology and Pathology, Institute of Animal Reproduction and Food Research, Polish Academy of Sciences, Tuwima 10, 10-748, Olsztyn, Poland. i.woclawek-potocka@pan.olsztyn.pl.
authors.forename: Izabela
authors.initials: I
authors.lastname: Woclawek-Potocka
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D001755:Blastocyst / Q000187:drug effects; D002417:Cattle; D054885:Cumulus Cells / Q000187:drug effects*; D046149:Embryo Culture Techniques; D005260:Female; D018507:Gene Expression Regulation, Developmental; D005947:Glucose / Q000378:metabolism*; D059471:In Vitro Oocyte Maturation Techniques / Q000379:methods*; D008246:Lysophospholipids / Q000494:pharmacology*; D009865:Oocytes / Q000187:drug effects* / Q000254:growth & development; D010060:Ovulation / Q000235:genetics
chemical_list: D008246:Lysophospholipids; D005947:Glucose; C032881:lysophosphatidic acid