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(Arteriosclerosis, Thrombosis, and Vascular Biology. 2009;29:1622.)
© 2009 American Heart Association, Inc.

Cell Biology/Signaling

Scavenger Receptors of Endothelial Cells Mediate the Uptake and Cellular Proatherogenic Effects of Carbamylated LDL

Eugene O. Apostolov; Sudhir V. Shah; Debarti Ray; Alexei G. Basnakian

From the Department of Pharmacology & Toxicology (E.O.A., D.R., A.G.B.) and the Division of Nephrology, Department of Internal Medicine (E.O.A., S.V.S., A.G.B.), University of Arkansas for Medical Sciences, Little Rock; and the Renal Medicine Service (S.V.S., A.G.B.), Central Arkansas Veterans Healthcare System, Little Rock, USA.

Correspondence to Alexei G. Basnakian, Department of Pharmacology & Toxicology, University of Arkansas for Medical Sciences, 4301 W Markham St, Slot 638, Little Rock, AR USA 72205. E-mail basnakianalexeig{at}uams.edu

Objective— Carbamylated LDL (cLDL) has been recently shown to have robust proatherogenic effects on human endothelial cells in vitro, suggesting cLDL may have a significant role in atherosclerosis in uremia. The current study was designed to determine which receptors are used by cLDL and thus cause the proatherogenic effects.

Methods and Results— In ex vivo or in vitro models as well as in intact animals, administration of cLDL was associated with endothelial internalization of cLDL and subendothelial translocation (transcytosis). In vitro recombinant LOX-1 and SREC-1 receptors showed the greatest cLDL binding. However, pretreatment of the endothelial cells with specific inhibiting antibodies demonstrated that cLDL binds mainly to LOX-1 and CD36 receptors. The transcytosis was dependent on SR-A1, SREC-1, and CD36 receptors whereas LOX-1 receptor was not involved. The cytotoxicity was mediated by several studied scavenger receptors, but cLDL-induced monocyte adhesion depended only on LOX-1. The cLDL-induced synthesis of LOX-1 protein significantly contributed to both cytotoxicity and accelerated monocyte adhesion to endothelial cells.

Conclusions— Our data suggest that cLDL uses a unique pattern of scavenger receptors. They show that LOX-1 receptor, and partially CD36, SREC-1, and SR-A1 receptors, are essential for the proatherogenic effects of cLDL on human endothelial cells.

Key Words: carbamylated LDL • LOX-1 • scavenger receptor • endothelial cells • atherosclerosis