Table 1. Binding of native HDL and acro-HDL to SR-BI and selective uptake of COE.
Binding to SR-BI(ng HDL protein/mg cell protein) ± SEM | Uptake of HDL-COE(ng HDL-COE protein/mg cell protein) ± SEM | ||||
---|---|---|---|---|---|
HDL | Acro-HDL | HDL | Acro-HDL | ||
Lipoproteinconcentration(μg/mL) | 2.5 | 27.5 ± 3.6 | 29.3 ± 2.6 | 179.2 ± 19.8 | 147.8 ± 21.5 |
5 | 54.1 ± 7.0 | 54.7 ± 4.1 | 324.0 ± 38.0 | 260.5 ± 35.4 | |
10 | 88.7 ± 9.2 | 108.9 ± 9.7 *** | 551.6 ± 64.1 | 591.3 ± 61.6 | |
25 | 117.3 ± 7.6 | 125.7 ± 7.6 | 1149.6 ± 133.1 | 963.5 ± 105.8 * | |
50 | 168.9 ± 5.8 | 205.4 ± 13.7 ** | 956.5 ± 153.6 | 1085.2 ± 164.9 | |
Time (min) | 5 | 18.0 ± 1.2 | 15.9 ± 1.7 | 5.3 ± 0.4 | 5.0 ± 0.4 |
10 | 27.3 ± 1.8 | 24.2 ± 1.8 | 9.1 ± 0.7 | 7.5 ± 0.7 * | |
20 | 35.1 ± 2.2 | 42.3 ± 0.9 ** | 16.0 ± 1.3 | 15.6 ± 1.5 | |
30 | 37.4 ± 2.4 | 39.4 ± 3.5 | 17.7 ± 2.7 | 18.0 ± 2.8 | |
45 | 44.3 ± 4.3 | 53.5 ± 2.3 * | 30.3 ± 5.0 | 21.4 ± 2.2 | |
90 | 52.0 ± 4.1 | 59.7 ± 3.9 ** | 46.3 ± 7.8 | 37.1 ± 6.2 * | |
180 | 45.8 ± 7.7 | 64.7 ± 3.1 * | 74.3 ± 15.3 | 68.1 ± 10.6 |
COS-7 cells transiently transfected with empty vector (pcDNA3) or human SR-BI were incubated with native- or acrolein-modified [125I]/[3H]-COE-labeled HDL. Binding of radiolabeled HDL/acro-HDL to SR-BI and selective uptake of HDL-COE were measured as a function of ligand concentration (for 1.5 hours at 37°C) or incubation time (ligand concentration of 10 μg/mL at 37°C). Values represent the mean ± SEM of at least four independent experiments, each performed in triplicate. Data sets are presented following subtraction of empty vector values. Statistical analyses were determined by paired t-test.
*p<0.05,
**p<0.01
***p<0.001