Abstract 15394: Novel Apolipoprotein E-derived ABCA1 Agonist Peptide (CS-6253) Promotes Reverse Cholesterol Transport in vitro and Induces de novo Formation of Apoa-I Containing preβ-1 HDL in Human Plasma
Modulation of the reverse cholesterol transport (RCT) pathway may provide a therapeutic target for the prevention and treatment of atherosclerotic cardiovascular disease. We evaluated a 26 amino acid apolipoprotein peptide CS-6253 (CS) in its ability to mimic apoA-I functionality in RCT in vitro.
CS acted as a substrate for ABCA1 in vitro, and when adding CS to human plasma a 4 fold increase in ABCA1 dependent cholesterol efflux capacity was noted. Incubation of plasma with CS increased preβ-1 HDL formation in a dose-dependent fashion (up to 4-fold) as determined by 2D-PAGGE. A time course study effect of CS on plasma HDL species showed conversion of α-HDL species to preβ-1 HDL after 2h incubation, 37°C in a process where CS displaces apoA-I from α-HDL species. Analysis of FPLC profiles by SDS-PAGGE and anti-CS or anti-apoA-I western blots, showed that the peptide binds to HDL similarly to apoA-I. This was associated with considerable increase of cholesterol in LDL and VLDL, as observed by FPLC when normalized to plasma incubated without peptide. Furthermore, nHDL-CS generated by incubating CS in the presence of BHK cells expressing ABCA1 labelled with 3[H]cholesterol increased LCAT activity significantly, although approximately 50% less efficient than nHDL-apoA-I (Fractional Esterification Rate =22.32±0.86%; vs nHDL-CS=10.64±0.35%, p<0.05). nHDL-CS generated by incubating CS in the presence of BHK cells expressing ABCA1 labelled with 3[H]choline at 37°C, promoted significant phosphatidyl choline transfer to apoB lipoproteins: (43±0.72%) for HDL-apoA-I and (68±0.21%, p<0.05) for nHDL-CS, respectively, confirming physiological remodeling in the presence of resident plasma lipoproteins. We then investigated kinetics for cholesterol delivery from HDL-CS to hepatic tissue via SR-BI using Fu5AH cells, and HDL-apoA-I as control; HDL-CS was efficient at promoting total cholesterol uptake into the Fu5AH cells (0.11±0.02 μM) but less than HDL-apoA-I (0.01±0.004 μM), p<0.05.
Our data suggests that CS promotes cholesterol efflux in plasma via generation of preβ-1 HDL. The expression of ABCA1 and formation of preβ-1 HDL with the cycling of apoA-I between the preβ and α-HDL are proposed here as a potential anti-atherogenic mechanisms of action of CS.
Author Disclosures: A. Hafiane: None. J. Bielicki: None. J. Johansson: None. J. Genest: None.
- © 2014 by American Heart Association, Inc.