Signal transduction pathways activated by chorionic gonadotropin in the primate endometrial epithelial cells.
Successful implantation requires synergism between the developing embryo and the receptive endometrium. In the baboon, infusion of chorionic gonadotropin (CG) modulates both morphology and physiology of the epithelial and stromal cells of the receptive endometrium. This study explored the signal transduction pathways activated by CG in endometrial epithelial cells from baboon (BE) and human (HES). Incubations of BE and HES cells with CG did not significantly alter adenylyl cyclase activity or increase intracellular cAMP when compared with Chinese hamster ovarian cells stably transfected with the full-length human CG/luteinizing hormone (LH) receptor (CHO-LH cells). However, in BE and HES cells, CG induced the phosphorylation of several proteins, among them, extracellular signal-regulated protein kinases 1 and 2 (ERK 1/2). Phosphorylation of ERK 1/2 in uterine epithelial cells was protein kinase A (PKA) independent. This novel signaling pathway is functional because, in response to CG stimulation, prostaglandin E(2) (PGE(2)) was released into the media and increased significantly 2 h following CG stimulation. CG-stimulated PGE(2) synthesis in epithelial cells was inhibited by a specific mitogen-activated protein kinase (MEK 1/2) inhibitor, PD 98059. In conclusion, immediate signal transduction pathways induced by CG in endometrial epithelial cells are cAMP independent and stimulate phosphorylation of ERK 1/2 via a MEK 1/2 pathway, leading to an increase in PGE(2) release as the possible result of cyclooxygenase-2 activation.
Srisuparp
Santha
S
Department of Obstetrics and Gynecology, University of Illinois at Chicago, Chicago, Illinois 60212-7313, USA.
Strakova
Zuzana
Z
Brudney
Allison
A
Mukherjee
Sutapa
S
Reierstad
Scott
S
Hunzicker-Dunn
Mary
M
Fazleabas
Asgerally T
AT
D000818:Animals; D016466:CHO Cells; D002460:Cell Line; D006063:Chorionic Gonadotropin / Q000494:pharmacology / Q000502:physiology*; D006224:Cricetinae; D000242:Cyclic AMP / Q000096:biosynthesis; D017362:Cyclic AMP Response Element-Binding Protein / Q000378:metabolism; D017868:Cyclic AMP-Dependent Protein Kinases / Q000502:physiology; D015232:Dinoprostone / Q000096:biosynthesis; D004717:Endometrium / Q000166:cytology / Q000502:physiology*; D004847:Epithelial Cells / Q000502:physiology; D005260:Female; D006801:Humans; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D010215:Papio; D010766:Phosphorylation / Q000187:drug effects; D011974:Receptors, LH / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology*
D006063:Chorionic Gonadotropin; D017362:Cyclic AMP Response Element-Binding Protein; D011974:Receptors, LH; D000242:Cyclic AMP; D017868:Cyclic AMP-Dependent Protein Kinases; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; D015232:Dinoprostone