title: Selective cholesteryl ester uptake from high density lipoprotein by human first trimester and term villous trophoblast cells.
abstract: As villous trophoblast does represent the contact zone between foetal and maternal tissues, the present in vitro study was aimed at investigating cholesterol supply from human high density lipoprotein subclass 3 (HDL(3)) to trophoblast cells isolated from human first trimester and term placenta. Binding of (125)I-HDL(3) was specific and saturable with similar K(d)-values for first trimester (54 microg HDL(3)-protein/ml) and term villous trophoblast cells (29 microg HDL(3)-protein/ml). The cell-association of (125)I-HDL(3) was 3-fold higher for term trophoblast cells while the specific cell-association of [(3)H]cholesterol ester(CE)-labelled HDL(3) was higher for first trimester trophoblast preparations. As a consequence, first trimester trophoblast cells have a pronounced capacity for selective CE-uptake from HDL(3). Competition experiments with native and oxidized low-density lipoprotein as well as cAMP-mediated stimulation of cell-association of [(3)H]CE-HDL(3) in both trophoblast preparations suggested the scavenger receptor class B, type I (SR-BI) as a likely receptor mediating this pathway. SR-BI m RNA could be identified by RT-PCR and Northern blot experiments in both trophoblast preparations. Western blot analysis and immunocytochemistry revealed high expression of SR-BI in first trimester trophoblast. A polyclonal antiserum raised against murine SR-BI significantly decreased cell-association of [(3)H]CE-HDL(3) in trophoblast cells. We conclude that human first trimester and term trophoblast cells express SR-BI which could serve as an efficient route for supplying cholesterol esters from maternal lipoproteins to foetal tissues.
authors.affiliation: Institute of Medical Biochemistry and Molecular Biology, Karl-Franzens University Graz, Austria.
authors.forename: C
authors.initials: C
authors.lastname: Wadsack
authors.forename: A
authors.initials: A
authors.lastname: Hammer
authors.forename: S
authors.initials: S
authors.lastname: Levak-Frank
authors.forename: G
authors.initials: G
authors.lastname: Desoye
authors.forename: K F
authors.initials: KF
authors.lastname: Kozarsky
authors.forename: B
authors.initials: B
authors.lastname: Hirschmugl
authors.forename: W
authors.initials: W
authors.lastname: Sattler
authors.forename: E
authors.initials: E
authors.lastname: Malle
mesh_terms: D000328:Adult; D000818:Animals; D001667:Binding, Competitive; D015153:Blotting, Western; D018955:CD36 Antigens / Q000235:genetics / Q000378:metabolism; D016466:CHO Cells; D002448:Cell Adhesion / Q000187:drug effects; D002788:Cholesterol Esters / Q000378:metabolism*; D002824:Chorionic Villi / Q000187:drug effects / Q000378:metabolism*; D006224:Cricetinae; D000242:Cyclic AMP / Q000494:pharmacology; D005260:Female; D019084:Fluorescent Antibody Technique, Indirect; D006801:Humans; D007743:Labor, Obstetric; D008075:Lipoproteins, HDL / Q000378:metabolism; D053440:Lipoproteins, HDL3; D008565:Membrane Proteins; D018613:Microscopy, Confocal; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D012333:RNA, Messenger / Q000378:metabolism; D011971:Receptors, Immunologic; D018110:Receptors, Lipoprotein; D051116:Receptors, Scavenger; D020133:Reverse Transcriptase Polymerase Chain Reaction; D051122:Scavenger Receptors, Class B; D014327:Trophoblasts / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*
chemical_list: D018955:CD36 Antigens; D002788:Cholesterol Esters; D008075:Lipoproteins, HDL; D053440:Lipoproteins, HDL3; D008565:Membrane Proteins; D012333:RNA, Messenger; D011971:Receptors, Immunologic; D018110:Receptors, Lipoprotein; D051116:Receptors, Scavenger; C495124:SCARB1 protein, human; C454739:Scarb1 protein, mouse; D051122:Scavenger Receptors, Class B; D000242:Cyclic AMP