title: GnRH I and II up-regulate MMP-26 expression through the JNK pathway in human cytotrophoblasts.
abstract: BACKGROUND
  Matrix metalloproteinase-26 (MMP-26), one of the main mediators of extracellular matrix (ECM) degradation, has been shown to exist in trophoblasts of human placenta and to play a role in trophoblast cell invasion. However, little is known about the regulation of MMP-26 expression in human trophoblasts. Recently, gonadotropin-releasing hormone I (GnRH I) and GnRH II have been shown to regulate the expression of MMP-2, MMP-9/tissue inhibitor of metalloproteinases 1 (TIMP-1), and urokinase plasminogen activator (uPA)/plasminogen activator inhibitor (PAI) in human trophoblasts, suggesting that these two hormones may work as paracrine and/or autocrine regulators in modulating the activities of various protease systems at the feto-maternal interface. In this study, we determined the regulatory effects of GnRH I and GnRH II on the expression of MMP-26 in human immortalized cytotrophoblast-like cell line, B6Tert-1.
  
  
  METHODS
  Real-time PCR was used to quantify mRNA levels of MMP-26 in human trophoblast-like cell line, B6Tert-1 and primary cultured cytotrophoblasts. Western blotting was used to characterize the expression of MMP-26 and the phosphorylation of c-Jun NH2-terminal kinase (JNK) and extracellular signal-regulated kinase 1/2 (ERK1/2) in B6Tert-1 cells after treatment with GnRH I and GnRH II.
  
  
  RESULTS
  We found that GnRH I increased MMP-26 expression in B6Tert-1 cells after 12 h of treatment at both the mRNA and protein level, while GnRH II increased MMP-26 expression beginning at 3 h of treatment. Treatment of GnRH I at 1 nM resulted in maximal increase of MMP-26 mRNA and protein levels, whereas GnRH II treatment at a concentration of 100 nM was required to induce maximal increase in MMP-26 expression. In addition, we demonstrated that the activation of JNK, but not ERK1/2, was required for GnRH I and II-stimulated MMP-26 production in B6Tert-1 cells and primary cytotrophoblasts.
  
  
  CONCLUSIONS
  These novel findings indicated that GnRH I and II could up-regulate MMP-26 expression through the JNK signaling pathway in human trophoblast-like/trophoblast cells.
authors.affiliation: State Key Laboratory of Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, PR China.
authors.forename: Jing
authors.initials: J
authors.lastname: Liu
authors.forename: Bin
authors.initials: B
authors.lastname: Cao
authors.forename: Yu-xia
authors.initials: YX
authors.lastname: Li
authors.forename: Xiao-qiu
authors.initials: XQ
authors.lastname: Wu
authors.forename: Yan-ling
authors.initials: YL
authors.lastname: Wang
mesh_terms: D018929:Cell Culture Techniques; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D005260:Female; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D007987:Gonadotropin-Releasing Hormone / Q000031:analogs & derivatives* / Q000494:pharmacology; D006801:Humans; D048031:JNK Mitogen-Activated Protein Kinases / Q000378:metabolism / Q000502:physiology*; D020782:Matrix Metalloproteinases / Q000235:genetics* / Q000378:metabolism; D053505:Matrix Metalloproteinases, Secreted / Q000235:genetics* / Q000378:metabolism; D011247:Pregnancy; D011261:Pregnancy Trimester, First / Q000235:genetics / Q000378:metabolism; D011498:Protein Precursors / Q000494:pharmacology*; D015398:Signal Transduction / Q000187:drug effects; D013997:Time Factors; D014327:Trophoblasts / Q000187:drug effects* / Q000378:metabolism; D015854:Up-Regulation / Q000187:drug effects
chemical_list: D011498:Protein Precursors; C050866:progonadoliberin I; D007987:Gonadotropin-Releasing Hormone; C047717:LHRH, His(5)-Trp(7)-Tyr(8)-; D048031:JNK Mitogen-Activated Protein Kinases; C410599:MMP26 protein, human; D020782:Matrix Metalloproteinases; D053505:Matrix Metalloproteinases, Secreted