LOX-1 mediates lysophosphatidylcholine-induced oxidized LDL uptake in smooth muscle cells.
A novel receptor for oxidized low-density lipoprotein (OxLDL), lectin-like OxLDL receptor (LOX-1), was cloned from endothelial cells. Since OxLDL is taken up by vascular smooth muscle cells (VSMC) in atheroma, we analyzed the inducible expression of LOX-1 in VSMC in the present study. Incubation of cultured bovine VSMC with lysophosphatidylcholine (LPC), an atherogenic component of OxLDL, increased the level of mRNA for LOX-1 in a dose- and time-dependent manner. Since LPC did not significantly change the half-life of LOX-1 mRNA, the induction seemed to occur at the transcriptional level. The induction accompanied an increase in the protein level of LOX-1 and activity of OxLDL uptake. Blocking antibody against LOX-1 significantly suppressed the enhanced uptake of OxLDL. Thus, LOX-1 is a major receptor for OxLDL in VSMC as in endothelial cells. The enhanced expression of LOX-1 by LPC suggests that OxLDL and LPC would progressively change the function of VSMC and accelerate atherogenesis in vivo.
Aoyama
T
T
Second Department of Internal Medicine, Gifu University School of Medicine, Gifu, Japan.
Chen
M
M
Fujiwara
H
H
Masaki
T
T
Sawamura
T
T
D000818:Animals; D001161:Arteriosclerosis / Q000378:metabolism; D002417:Cattle; D002478:Cells, Cultured; D008077:Lipoproteins, LDL / Q000378:metabolism*; D008244:Lysophosphatidylcholines / Q000494:pharmacology; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000378:metabolism*; D010084:Oxidation-Reduction; D012333:RNA, Messenger / Q000378:metabolism; D011973:Receptors, LDL / Q000235:genetics / Q000378:metabolism*; D051131:Receptors, Oxidized LDL
D008077:Lipoproteins, LDL; D008244:Lysophosphatidylcholines; D012333:RNA, Messenger; D011973:Receptors, LDL; D051131:Receptors, Oxidized LDL; C099252:oxidized low density lipoprotein