title: Gonadotropin releasing hormone and transforming growth factor beta activate mitogen-activated protein kinase/extracellularly regulated kinase and differentially regulate fibronectin, type I collagen, and plasminogen activator inhibitor-1 expression in leiomyoma and myometrial smooth muscle cells.
abstract: GnRH analog (GnRHa) and TGF-beta act directly on leiomyoma/myometrial smooth muscle cells (LSMCs and MSMCs) regulating diverse activities resulting in leiomyoma growth and regression. Because GnRH and TGF-beta receptor signaling is in part mediated through the MAPK pathway, we determined whether the contribution of MAPK/ERK and transcriptional activation of c-fos and c-jun, result in differential regulation of type I collagen, fibronectin, and plasminogen activator inhibitor 1 (PAI-1) gene expression, whose products are known to influence extracellular matrix turnover, which is critical in leiomyoma growth and GnRHa-induced regression. We found that GnRHa and TGF-beta in a dose- and time-dependent manner increased the level of phosphorylated ERK1/2 (pERK1/2) in LSMCs and MSMCs. GnRHa and TGF-beta increased ERK1/2 nuclear accumulation resulting in differential regulation of c-fos and c-jun mRNA expression via downstream signaling from MAPK kinase (MEK)1/2, because pretreatment with U0126, a synthetic inhibitor of MEK1/2, abolished basal and GnRHa- and TGF-beta-induced pERK1/2 and the expression of c-fos and c-jun. LSMCs and MSMCs also express fibronectin, type I collagen, and PAI-1 mRNA, and GnRHa and TGF-beta altered their expression in a cell-specific manner through MEK1/2. We concluded that GnRHa and TGF-beta acting through a MAPK/ERK pathway and transcriptional activation of c-fos/c-jun results in differential regulation of specific genes whose products may in part influence the outcome of leiomyoma growth and regression.
authors.affiliation: Department of Obstetrics and Gynecology, University of Florida, Box 100294, Gainesville, Florida 32610, USA.
authors.forename: Li
authors.initials: L
authors.lastname: Ding
authors.forename: Jingxia
authors.initials: J
authors.lastname: Xu
authors.forename: Xiaoping
authors.initials: X
authors.lastname: Luo
authors.forename: Nasser
authors.initials: N
authors.lastname: Chegini
mesh_terms: D024042:Collagen Type I / Q000235:genetics*; D004789:Enzyme Activation; D005260:Female; D005353:Fibronectins / Q000235:genetics*; D005786:Gene Expression Regulation / Q000187:drug effects*; D016762:Genes, fos; D016758:Genes, jun; D007987:Gonadotropin-Releasing Hormone / Q000031:analogs & derivatives* / Q000494:pharmacology*; D006801:Humans; D007889:Leiomyoma / Q000378:metabolism*; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D032389:Myocytes, Smooth Muscle / Q000378:metabolism*; D009215:Myometrium / Q000378:metabolism*; D017395:Plasminogen Activator Inhibitor 1 / Q000235:genetics*; D016212:Transforming Growth Factor beta / Q000494:pharmacology*; D014594:Uterine Neoplasms / Q000378:metabolism*
chemical_list: D024042:Collagen Type I; D005353:Fibronectins; D017395:Plasminogen Activator Inhibitor 1; D016212:Transforming Growth Factor beta; D007987:Gonadotropin-Releasing Hormone; C083781:LHRH, Ala(6)-Gly(10)-ethylamide-; D020928:Mitogen-Activated Protein Kinases