title: Differential regulation of 11 beta-hydroxysteroid dehydrogenase type 1 and 2 by nitric oxide in cultured human placental trophoblast and chorionic cell preparation.
abstract: Two types of 11 beta-hydroxysteroid dehydrogenase (11 beta-HSD) have been identified in different tissues. Type 1 has both oxidase and reductase activities interconverting cortisol and cortisone, whereas type 2 has only oxidase activity converting cortisol to cortisone. It has been proposed that placental 11 beta-HSD controls the passage of maternal glucocorticoids to the fetal circulation. However, little is known about the regulation of 11 beta-HSD in the human placenta and fetal membranes. We cultured human term placental trophoblast and chorionic trophoblast cells to examine effects of nitric oxide donors, sodium nitroprusside (SNP) and S-nitroso-N-acetyl penicillamine (SNAP), on the activity and messenger RNA (mRNA) expression of 11 beta-HSD. At 72 h of culture, placental trophoblast formed syncytial clumps that were cytokeratin positive and displayed mainly type 2 oxidase activity, although some type 1 reductase activity was detectable. Chorion preparations contain greater than 90% trophoblast cells as demonstrated by immunostaining for cytokeratin and less than 5% vimentin positive cells. Type 1 reductase activity predominated in the chorionic trophoblast cells with barely detectable type 1 or type 2 oxidase activity. Both SNP (1-400 microM) and SNAP (1 mM) inhibited placental 11 beta-HSD type 2 oxidase activity but not type 1 reductase activity either in placental or chorionic cells. An inhibitory effect on type 2 oxidase activity was reproduced in part by 8-bromo cGMP, blocked partially by the guanylate cyclase inhibitor LY83583 (1 microM), but not by an ADP-ribosylation inhibitor N, N'-hexamethylene-bis-acetamide (HMBG) (10 mM). SNP also suppressed the expression of type 2 mRNA in cultured placental trophoblast in a dose-dependent manner, and this effect was also blocked by LY83583. We conclude that human placental trophoblast possesses predominantly 11 beta-HSD type 2 oxidase activity, whereas chorionic cells possess mainly type 1 reductase activity under the culture conditions employed. Nitric oxide specifically attenuated 11 beta-HSD type 2 oxidase activity as well as its mRNA expression in the placental trophoblast. The effect was mediated at least partially through the cGMP pathway, although an alternative pathway other than ADP-ribosylation may exist.
authors.affiliation: Department of Physiology, University of Toronto, Ontario, Canada. kang.sun@utoronto.ca
authors.forename: K
authors.initials: K
authors.lastname: Sun
authors.forename: K
authors.initials: K
authors.lastname: Yang
authors.forename: J R
authors.initials: JR
authors.lastname: Challis
mesh_terms: D042842:11-beta-Hydroxysteroid Dehydrogenases; D000328:Adult; D002478:Cells, Cultured; D002823:Chorion / Q000166:cytology / Q000201:enzymology*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005260:Female; D006801:Humans; D006913:Hydroxysteroid Dehydrogenases / Q000235:genetics / Q000378:metabolism*; D007527:Isoenzymes / Q000235:genetics / Q000378:metabolism*; D007700:Kinetics; D009569:Nitric Oxide / Q000502:physiology*; D009599:Nitroprusside / Q000494:pharmacology; D010396:Penicillamine / Q000031:analogs & derivatives / Q000494:pharmacology; D010920:Placenta / Q000166:cytology*; D012333:RNA, Messenger / Q000378:metabolism; D026423:S-Nitroso-N-Acetylpenicillamine; D014327:Trophoblasts / Q000201:enzymology*
chemical_list: D004791:Enzyme Inhibitors; D007527:Isoenzymes; D012333:RNA, Messenger; D009599:Nitroprusside; D009569:Nitric Oxide; D026423:S-Nitroso-N-Acetylpenicillamine; D006913:Hydroxysteroid Dehydrogenases; D042842:11-beta-Hydroxysteroid Dehydrogenases; D010396:Penicillamine