Molecular regulation of human placental growth factor (PlGF) gene expression in placental villi and trophoblast cells is mediated via the protein kinase a pathway.
Cyclic 3',5'-adenosine monophosphate (cAMP) is a critical second messenger for human trophoblasts and regulates the expression of numerous genes. It is known to stimulate in vitro the fusion and differentiation of BeWo choriocarcinoma cells, which acquire characteristics of syncytiotrophoblasts. A DNA microarray analysis of BeWo cells undergoing forskolin-induced syncytialization revealed that among the induced genes, placental growth factor (PlGF) was 10-fold upregulated. We verified this result in two choriocarcinoma cell lines, BeWo and JEG-3, and also in first trimester placental villous explants by quantifying PlGF mRNA (real time PCR) and PlGF protein secreted into the supernatant (ELISA). Similar effects were noted for vascular endothelial growth factor (VEGF) mRNA and protein expression. Treatment with cholera toxin and the use of a specific inhibitor of protein kinase A (PKA) blocked these effects, indicating that the cAMP/PKA pathway is responsible for the cAMP-induced upregulation of PlGF and that one or more G protein coupled receptor(s) was involved. We identified two functional cAMP responsive elements (CRE) in the PlGF promoter and demonstrated that the CRE binding protein, CREB, contributes to the regulation of PlGF gene expression. We speculate that defects in this signaling pathway may lead to abnormal secretion of PlGF protein as observed in the pregnancy-related diseases preeclampsia and intrauterine growth restriction.
Laboratoire d'obstétrique, Université Catholique de Louvain-Bruxelles, Belgium.
Christophe
C
Depoix
Meng Kian
MK
Tee
Robert N
RN
Taylor
D045744:Cell Line, Tumor; D002824:Chorionic Villi / Q000378:metabolism / Q000502:physiology*; D000242:Cyclic AMP / Q000378:metabolism; D017362:Cyclic AMP Response Element-Binding Protein / Q000378:metabolism; D017868:Cyclic AMP-Dependent Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D005260:Female; D006801:Humans; D066298:In Vitro Techniques; D000072483:Placenta Growth Factor; D011247:Pregnancy; D011257:Pregnancy Proteins / Q000096:biosynthesis* / Q000235:genetics; D011261:Pregnancy Trimester, First; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D012333:RNA, Messenger / Q000737:chemistry / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D042461:Vascular Endothelial Growth Factor A / Q000096:biosynthesis / Q000235:genetics
D017362:Cyclic AMP Response Element-Binding Protein; C000608036:PGF protein, human; D011257:Pregnancy Proteins; D047428:Protein Kinase Inhibitors; D012333:RNA, Messenger; C467484:VEGFA protein, human; D042461:Vascular Endothelial Growth Factor A; D000072483:Placenta Growth Factor; D000242:Cyclic AMP; D017868:Cyclic AMP-Dependent Protein Kinases