title: Regulation of placental villous angiopoietin-1 and -2 expression by estrogen during baboon pregnancy.
abstract: We recently showed an increase in vascular endothelial growth factor (VEGF), decrease in angiopoietin-1 (Ang-1) and unaltered Ang-2 expression by the villous placenta with advancing baboon pregnancy. Moreover, placental VEGF expression was increased by estrogen in early pregnancy. In the present study, we determined whether placental Ang-1 and Ang-2 are regulated by estrogen. Ang-1 and Ang-2 mRNA and protein were determined by RT-PCR and immunocytochemistry in the placenta of baboons on Day 60 of gestation (term is 184 days) after administration of estrogen precursor androstenedione on Days 25-59 or on Day 54 after acute estradiol administration. Chronic androstenedione treatment increased serum estradiol levels three-fold (P < 0.001) and decreased (P < 0.05) villous cytotrophoblast Ang-1 mRNA to a level (0.36 +/- 0.08 relative to 18S rRNA) that was one-third of that in untreated animals (0.98 +/- 0.26). Within 2 hr of estradiol administration, cytotrophoblast Ang-1 mRNA was decreased to a level (0.24 +/- 0.05) one-fifth (P < 0.05) of that in untreated animals (1.14 +/- 0.23). However, Ang-2 mRNA levels were unaltered. Ang-1, Ang-2 and estrogen receptors alpha and beta protein were localized within villous cytotrophoblasts providing a mechanism for estrogen action at this site. In summary, estrogen increased VEGF, decreased Ang-1, and had no effect on Ang-2 expression within placental cytotrophoblasts during early baboon pregnancy. We propose that the estrogen-dependent differential regulation of these angioregulatory factors underpins the unique pattern of neovascularization established within the villous placenta during primate pregnancy.
authors.affiliation: Department of Obstetrics, Center for Studies in Reproduction, University of Maryland School of Medicine, Baltimore, Maryland 21201, USA. ealbrech@umaryland.edu
authors.forename: Eugene D
authors.initials: ED
authors.lastname: Albrecht
authors.forename: Jeffery S
authors.initials: JS
authors.lastname: Babischkin
authors.forename: Gerald J
authors.initials: GJ
authors.lastname: Pepe
mesh_terms: D042683:Angiopoietin-1 / Q000235:genetics* / Q000378:metabolism; D042702:Angiopoietin-2 / Q000235:genetics* / Q000378:metabolism; D000818:Animals; D002824:Chorionic Villi / Q000378:metabolism*; D047628:Estrogen Receptor alpha / Q000378:metabolism; D047629:Estrogen Receptor beta / Q000378:metabolism; D004967:Estrogens / Q000097:blood / Q000494:pharmacology*; D005260:Female; D005786:Gene Expression Regulation / Q000187:drug effects*; D008297:Male; D008954:Models, Biological; D010215:Papio / Q000235:genetics* / Q000502:physiology; D011247:Pregnancy; D011270:Pregnancy, Animal; D011374:Progesterone / Q000097:blood; D012333:RNA, Messenger / Q000378:metabolism; D013997:Time Factors
chemical_list: D042683:Angiopoietin-1; D042702:Angiopoietin-2; D047628:Estrogen Receptor alpha; D047629:Estrogen Receptor beta; D004967:Estrogens; D012333:RNA, Messenger; D011374:Progesterone