title: Nitric oxide and cGMP induce COX-2 expression and PGE2 production in human granulosa cells through CREB signaling pathway.
abstract: BACKGROUND
  It is well known that cyclooxygenase-2 (COX-2) and its major derivative product prostaglandin E2 (PGE2) play key regulatory roles in the ovulation process. Animal studies have demonstrated that the inhibition of nitric oxide (NO) suppresses ovarian PGE2 production and ovulation. Although the expression of NO synthases has been detected in human granulosa cells, the effect of NO on COX-2 expression and PGE2 production in these cells remains unknown.
  
  
  OBJECTIVE
  The purpose of this article was to investigate the effects of NO on COX-2 expression and PGE2 production in human granulosa cells.
  
  
  METHODS
  SVOG cells are human granulosa cells that were obtained from women undergoing in vitro fertilization and immortalized with simian virus 40 large T antigen. SVOG cells were used to investigate the effects of NO on COX-2 expression and PGE2 production.
  
  
  METHODS
  The study was conducted in an academic research center.
  
  
  METHODS
  The levels of mRNA and protein were examined by RT-quantitative real-time PCR and Western blotting, respectively. The accumulation levels of PGE2 were measured by ELISA.
  
  
  RESULTS
  Treatment with the NO donor S-nitroso-N-acetyl-DL-penicillamine (SNAP) induced COX-2 expression and PGE2 production. In addition, the stimulatory effect of SNAP on COX-2 and PGE2 was mimicked by treatment with the cGMP analog 8-bromo-cGMP (8-Br-cGMP). Interestingly, neither SNAP nor 8-Br-cGMP affected the expression of COX-1. Moreover, our results showed that either SNAP or 8-Br-cGMP activated cAMP response element-binding protein (CREB) signaling and that the knockdown of CREB attenuated SNAP- and 8-Br-cGMP-induced COX-2 expression and PGE2 production.
  
  
  CONCLUSIONS
  CREB mediates NO and cGMP-induced COX-2 expression and PGE2 production, which subsequently contribute to NO-regulated ovulation in human granulosa cells.
authors.affiliation: Reproductive Medical Center (L.F., Y.-P.S.), The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China 450052; and Department of Obstetrics and Gynaecology (H.-M.C., J.-C.C., P.C.K.L.), Child & Family Research Institute, University of British Columbia, Vancouver, British Columbia V5Z 4H4, Canada.
authors.forename: Lanlan
authors.initials: L
authors.lastname: Fang
authors.forename: Hsun-Ming
authors.initials: HM
authors.lastname: Chang
authors.forename: Jung-Chien
authors.initials: JC
authors.lastname: Cheng
authors.forename: Peter C K
authors.initials: PC
authors.lastname: Leung
authors.forename: Ying-Pu
authors.initials: YP
authors.lastname: Sun
mesh_terms: D002460:Cell Line; D017362:Cyclic AMP Response Element-Binding Protein / Q000378:metabolism*; D006152:Cyclic GMP / Q000494:pharmacology*; D051546:Cyclooxygenase 2 / Q000378:metabolism*; D015232:Dinoprostone / Q000378:metabolism*; D005260:Female; D006107:Granulosa Cells / Q000187:drug effects* / Q000378:metabolism; D006801:Humans; D009569:Nitric Oxide / Q000378:metabolism*; D026423:S-Nitroso-N-Acetylpenicillamine / Q000494:pharmacology; D015398:Signal Transduction / Q000187:drug effects*; D015854:Up-Regulation / Q000187:drug effects
chemical_list: D017362:Cyclic AMP Response Element-Binding Protein; D009569:Nitric Oxide; D026423:S-Nitroso-N-Acetylpenicillamine; D051546:Cyclooxygenase 2; D006152:Cyclic GMP; D015232:Dinoprostone