title: Matrix metalloproteinases 2 and 9 mediate epidermal growth factor receptor transactivation by gonadotropin-releasing hormone.
abstract: Rapid engagement of the extracellular signal-regulated kinase (ERK) cascade via the Gq/11-coupled GnRH receptor (GnRHR) is mediated by transactivation of the epidermal growth factor receptor (EGFR). Here we show that the cross-talk between GnRHR and EGFR in gonadotropic cells is accomplished via gelatinases A and B (matrix metalloproteinases (MMPs) 2 and 9), identifying gelatinases as the first distinct members of the MMP family mediating EGFR transactivation by G protein-coupled receptors. Using a specific MMP2 and MMP9 inhibitor, Ro28-2653, GnRH-dependent EGFR transactivation was abrogated. Proving the specificity of the effect, transient transfection of alphaT3-1 cells with ribozymes directed against MMP2 or MMP9 specifically blocked EGFR tyrosine phosphorylation in response to GnRH stimulation. GnRH challenge of alphaT3-1 cells furthered the release of active MMP2 and MMP9 and increased their gelatinolytic activities within 5 min. Rapid release of activated MMP2 or MMP9 was inhibited by ribozyme-targeted down-regulation of MT1-MMP or MMP2, respectively. We found that GnRH-induced Src, Ras, and ERK activation were also gelatinase-dependent. Thus, gelatinase-induced EGFR transactivation was required to engage the extracellular-signal regulated kinase cascade. Activation of c-Jun N-terminal kinase and p38 MAPK by GnRH was unaffected by EGFR or gelatinase inhibition that, however, suppressed GnRH induction of c-Jun and c-Fos. Our findings suggest a novel role for gelatinases in the endocrine regulation of pituitary gonadotropes.
authors.affiliation: Institut für Pharmakologie und Toxikologie, Philipps Universität Marburg, Karl-von-Frisch-Strasse 1, 35033 Marburg, Germany.
authors.forename: Susanne
authors.initials: S
authors.lastname: Roelle
authors.forename: Robert
authors.initials: R
authors.lastname: Grosse
authors.forename: Achim
authors.initials: A
authors.lastname: Aigner
authors.forename: H W
authors.initials: HW
authors.lastname: Krell
authors.forename: Frank
authors.initials: F
authors.lastname: Czubayko
authors.forename: Thomas
authors.initials: T
authors.lastname: Gudermann
mesh_terms: D000818:Animals; D002460:Cell Line; D004791:Enzyme Inhibitors / Q000494:pharmacology; D066246:ErbB Receptors / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism; D007987:Gonadotropin-Releasing Hormone / Q000502:physiology*; D020935:MAP Kinase Signaling System; D020778:Matrix Metalloproteinase 2 / Q000502:physiology*; D020780:Matrix Metalloproteinase 9 / Q000502:physiology*; D061965:Matrix Metalloproteinase Inhibitors; D051379:Mice; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D016337:RNA, Catalytic / Q000494:pharmacology; D020239:Receptor Cross-Talk; D043562:Receptors, G-Protein-Coupled / Q000502:physiology; D015533:Transcriptional Activation
chemical_list: D004791:Enzyme Inhibitors; D061965:Matrix Metalloproteinase Inhibitors; D016337:RNA, Catalytic; D043562:Receptors, G-Protein-Coupled; D007987:Gonadotropin-Releasing Hormone; D066246:ErbB Receptors; D020928:Mitogen-Activated Protein Kinases; D020778:Matrix Metalloproteinase 2; D020780:Matrix Metalloproteinase 9