title: Gonadotrophin-releasing hormone antagonist induces apoptosis in human decidual stromal cells: effect on GADD45α and MAPK signaling.
abstract: BACKGROUND
  The impact of gonadotrophin-releasing hormone (GnRH) antagonists used in IVF protocols on endometrial tissue remodeling, embryo implantation and the programming of early pregnancy is still unclear. Pregnancy and infant outcomes after treatment with GnRH antagonist for IVF are particular causes of concern. The purpose of this study was to investigate the mechanisms of GnRH antagonist-induced apoptosis of human decidual stromal cells and the effects of GnRH antagonist on the activation of ERK1/2, JNK and GADD45α signaling.
  
  
  METHODS
  Human decidual stromal cells were isolated from decidual tissue. The expression of GnRH-I receptor (GnRH-IR) was examined by immunoblot analysis and immunohistochemistry. The cells were treated with the GnRH antagonist, Cetrorelix. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazoliumbromide assay was used to examine cell viability. Cleaved caspase-3 and terminal deoxynucleotidyl transferase-mediated dUDP nick-end labeling assay were used as indicators for cell apoptosis. Mitogen-activated protein kinase function was tested for the elucidation of intracellular signalings through the pre-treatment of stromal cells with ERK1/2 (U0126) and JNK (SP600125) inhibitors prior to the Cetrorelix treatment. To characterize the signaling pathway of GnRH antagonist, the endogenous GnRH-IR and GADD45α were knocked down by specific small-interfering RNA (siRNA).
  
  
  RESULTS
  The GnRH-IR is expressed in human decidual stromal cells. Treatment with GnRH antagonist decreased cell viability, induced apoptosis and increased the phosphorylation of ERK1/2 and JNK. Cells pre-treated with U0126 and SP600125 were rescued from the GnRH antagonist-mediated inhibition of cell growth and did not exhibit GnRH antagonist-induced apoptosis and downstream GADD45α signaling. GnRH antagonist-mediated cell growth inhibition and apoptosis were also abolished by the knockdown of the endogenous GnRH-IR or GADD45α with siRNAs.
  
  
  CONCLUSIONS
  The GnRH antagonist suppresses the growth of decidual stromal cells by inducing apoptosis through the GnRH-IR and through the ERK1/2 and JNK phosphorylation-dependent induction of GADD45α signaling. These results indicate that ERK1/2, JNK and GADD45α are coordinately regulated by the GnRH antagonist through the GnRH-IR to induce apoptosis in human decidual stromal cells, suggesting that the GnRH antagonist may play a role in decidual programming in human pregnancy.
authors.affiliation: Department of Obstetrics and Gynecology, Chang Gung Memorial Hospital Linkou Medical Center, Taoyuan 333, Taiwan ROC. danielwu@cgmh.org.tw
authors.forename: Hsien-Ming
authors.initials: HM
authors.lastname: Wu
authors.forename: Hsin-Shih
authors.initials: HS
authors.lastname: Wang
authors.forename: Yung-Kuei
authors.initials: YK
authors.lastname: Soong
authors.forename: Hong-Yuan
authors.initials: HY
authors.lastname: Huang
authors.forename: Chun-Kai
authors.initials: CK
authors.lastname: Chen
authors.forename: Chyi-Long
authors.initials: CL
authors.lastname: Lee
authors.forename: Peter C K
authors.initials: PC
authors.lastname: Leung
mesh_terms: D000328:Adult; D017209:Apoptosis / Q000187:drug effects*; D018797:Cell Cycle Proteins / Q000378:metabolism*; D002478:Cells, Cultured; D003656:Decidua / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D005260:Female; D055785:Gene Knockdown Techniques; D007987:Gonadotropin-Releasing Hormone / Q000037:antagonists & inhibitors*; D006801:Humans; D020935:MAP Kinase Signaling System / Q000187:drug effects; D009687:Nuclear Proteins / Q000378:metabolism*; D010766:Phosphorylation; D034741:RNA, Small Interfering; D011966:Receptors, LHRH / Q000378:metabolism; D017154:Stromal Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D000097642:GADD45 Proteins
chemical_list: D018797:Cell Cycle Proteins; D007987:Gonadotropin-Releasing Hormone; D009687:Nuclear Proteins; D034741:RNA, Small Interfering; D011966:Receptors, LHRH; C439070:GADD45A protein, human; D000097642:GADD45 Proteins