Competitive inhibition of LDL binding and uptake by HDL in aortic endothelial cells

Journal Article · Sat Sep 01 00:00:00 EDT 1990 · Journal of Surgical Research; (USA)

DOI:https://doi.org/10.1016/0022-4804(90)90128-O· OSTI ID:6511226

Alexander, J J; Miguel, R; Graham, D ^[1]

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1. Case Western Reserve Univ. School of Medicine, OH (USA)

High-density lipoprotein (HDL) may inhibit the binding and cellular uptake of low-density lipoprotein (LDL) as one means of regulating the delivery of exogenous cholesterol to nonhepatic tissues. This may play an important role in atherogenesis, by altering lipid metabolism in cells of the arterial wall. To verify and better characterize this effect, endothelial cells were harvested from bovine aorta and maintained in tissue culture. Following initial preincubation in lipid-deficient culture media, these cells were incubated for 2 hr at 4 degrees C in media containing 125I-LDL (10 micrograms protein/ml) and varying concentrations of either HDL (0-400 micrograms protein/ml) or comparable amounts of Apoprotein A (Apo A), the major protein component of HDL. Intracellular and trypsin-released counts were assayed separately, as a measurement of cellular uptake and membrane bound LDL, respectively. Results of this study indicated an inhibition of LDL binding and uptake by HDL (P less than 0.005, ANOVA). A similar inhibition was found with Apo A alone (P less than 0.005). When identical studies were performed using 125I-Apoprotein B, the protein component of LDL, and Apo A, the latter was found to inhibit the binding of Apo B to the same extent (P less than 0.0006). These results indicate that HDL does inhibit LDL binding and uptake by bovine aortic endothelial cells and that, because this effect is seen equally with only the protein component of these lipoprotein particles, it is most likely due to competitive binding at the receptor level rather than to stearic hindrance or an alteration of the cell membrane.

• OSTI ID: 6511226
• Journal Information: Journal of Surgical Research; (USA), Vol. 49:3; ISSN 0022-4804
• Country of Publication: United States
• Language: English

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59 BASIC BIOLOGICAL SCIENCES
ARTERIOSCLEROSIS
PATHOGENESIS
LIPOPROTEINS
BIOCHEMICAL REACTION KINETICS
UPTAKE
AORTA
CATTLE
CELL MEMBRANES
CHOLESTEROL
CPB
ENDOTHELIUM
INHIBITION
IODINE 125
TISSUE CULTURES
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BODY
CARDIOVASCULAR DISEASES
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DOMESTIC ANIMALS
ELECTRON CAPTURE RADIOISOTOPES
HYDROXY COMPOUNDS
INTERMEDIATE MASS NUCLEI
IODINE ISOTOPES
ISOTOPES
KINETICS
LIPIDS
MAMMALS
MEMBRANES
NUCLEI
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
ORGANS
PROTEINS
RADIOISOTOPES
REACTION KINETICS
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