Identification of the lectin-like receptor for oxidized low-density lipoprotein in human macrophages and its potential role as a scavenger receptor.
A new receptor for oxidized low-density lipoprotein (LDL), lectin-like oxidized LDL receptor-1 (LOX-1), has recently been cloned from bovine endothelial cells and human lung. A limited tissue-distribution study suggested that the protein was mainly produced by the vascular endothelium. In the present study we demonstrate that LOX-1 is also expressed in macrophages, where it may function as a scavenger receptor. LOX-1 was not detected in undifferentiated THP-1 cells or in freshly isolated human blood monocytes. However, mature human monocyte-derived macrophages and differentiated THP-1 cells showed high levels of LOX-1 transcripts. Consistent with these results, immunofluorescence staining and FACS analysis demonstrated that LOX-1 protein is expressed on the plasma membrane of macrophages. Western-blot analysis of membranes from macrophages (but not those from monocytes) identified a single band, with an apparent molecular mass of about 40 kDa, that displayed oxidized LDL-binding activity. These results suggest that differentiation induces the expression of LOX-1 in macrophages, where it may play a role as a scavenger receptor and/or a receptor for oxidized LDL.
University of California, San Diego, Department of Medicine, 0682, 9500 Gilman Drive, La Jolla, CA 92093, USA.
H
H
Yoshida
N
N
Kondratenko
S
S
Green
D
D
Steinberg
O
O
Quehenberger
D000818:Animals; D002417:Cattle; D002454:Cell Differentiation; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism; D004730:Endothelium, Vascular / Q000378:metabolism; D005434:Flow Cytometry; D005786:Gene Expression Regulation; D006801:Humans; D007150:Immunohistochemistry; D008077:Lipoproteins, LDL / Q000378:metabolism*; D008168:Lung / Q000378:metabolism; D008264:Macrophages / Q000166:cytology / Q000378:metabolism*; D008565:Membrane Proteins; D008970:Molecular Weight; D009000:Monocytes / Q000166:cytology; D016133:Polymerase Chain Reaction; D011971:Receptors, Immunologic / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D011973:Receptors, LDL / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D018110:Receptors, Lipoprotein; D051131:Receptors, Oxidized LDL; D051116:Receptors, Scavenger; D051122:Scavenger Receptors, Class B; D051127:Scavenger Receptors, Class E
D008077:Lipoproteins, LDL; D008565:Membrane Proteins; C495137:OLR1 protein, human; D011971:Receptors, Immunologic; D011973:Receptors, LDL; D018110:Receptors, Lipoprotein; D051131:Receptors, Oxidized LDL; D051116:Receptors, Scavenger; C454739:Scarb1 protein, mouse; D051122:Scavenger Receptors, Class B; D051127:Scavenger Receptors, Class E; C099252:oxidized low density lipoprotein