Human endothelial cells of the placental barrier efficiently deliver cholesterol to the fetal circulation via ABCA1 and ABCG1

Although maternal-fetal cholesterol transfer may serve to compensate for insufficient fetal cholesterol biosynthesis under pathological conditions, it may have detrimental consequences under conditions of maternal hypercholesterolemia leading to preatherosclerotic lesion development in fetal aortas....

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Published in:Circulation research Vol. 104; no. 5; p. 600
Main Authors: Stefulj, Jasminka, Panzenboeck, Ute, Becker, Tatjana, Hirschmugl, Birgit, Schweinzer, Cornelia, Lang, Ingrid, Marsche, Gunther, Sadjak, Anton, Lang, Uwe, Desoye, Gernot, Wadsack, Christian
Format: Journal Article
Language:English
Published: United States 13.03.2009
Subjects:
Apolipoprotein A-I - metabolism
ATP Binding Cassette Transporter 1
ATP Binding Cassette Transporter, Subfamily G
ATP Binding Cassette Transporter, Subfamily G, Member 1
ATP-Binding Cassette Transporters - antagonists & inhibitors
ATP-Binding Cassette Transporters - genetics
ATP-Binding Cassette Transporters - metabolism
Cell Membrane - metabolism
Cells, Cultured
Cholesterol - metabolism
DNA-Binding Proteins - metabolism
Endothelial Cells - drug effects
Endothelial Cells - metabolism
Female
Glyburide - pharmacology
Humans
Lipoproteins, HDL3 - metabolism
Liver X Receptors
Maternal-Fetal Exchange
Orphan Nuclear Receptors
Placenta - blood supply
Pregnancy
Probucol - pharmacology
Receptors, Cytoplasmic and Nuclear - metabolism
RNA Interference
RNA, Small Interfering - metabolism
Scavenger Receptors, Class B - metabolism
Time Factors
ISSN:1524-4571, 1524-4571
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Summary:Although maternal-fetal cholesterol transfer may serve to compensate for insufficient fetal cholesterol biosynthesis under pathological conditions, it may have detrimental consequences under conditions of maternal hypercholesterolemia leading to preatherosclerotic lesion development in fetal aortas. Maternal cholesterol may enter fetal circulation by traversing syncytiotrophoblast and endothelial layers of the placenta. We hypothesized that endothelial cells (ECs) of the fetoplacental vasculature display a high and tightly regulated capacity for cholesterol release. Using ECs isolated from human term placenta (HPECs), we investigated cholesterol release capacity and examined transporters involved in cholesterol efflux pathways controlled by liver-X-receptors (LXRs). HPECs demonstrated 2.5-fold higher cholesterol release to lipid-free apolipoprotein (apo)A-I than human umbilical vein ECs (HUVECs), whereas both cell types showed similar cholesterol efflux to high-density lipoproteins (HDLs). Interestingly, treatment of HPECs with LXR activators increased cholesterol efflux to both types of acceptors, whereas no such response could be observed for HUVECs. In line with enhanced cholesterol efflux, LXR activation in HPECs increased expression of ATP-binding cassette transporters ABCA1 and ABCG1, while not altering expression of ABCG4 and scavenger receptor class B type I (SR-BI). Inhibition of ABCA1 or silencing of ABCG1 decreased cholesterol efflux to apoA-I (-70%) and HDL(3) (-57%), respectively. Immunohistochemistry localized both transporters predominantly to the apical membranes of placental ECs in situ. Thus, ECs of human term placenta exhibit unique, efficient and LXR-regulated cholesterol efflux mechanisms. We propose a sequential pathway mediated by ABCA1 and ABCG1, respectively, by which HPECs participate in forming mature HDL in the fetal blood.
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ISSN:1524-4571
1524-4571
DOI:10.1161/CIRCRESAHA.108.185066