Abstract 473: Development of High-throughput ABCA1, ABCG1 and SR-BI Mediated HDL Efflux Assays

Studies have shown an inverse association between HDL-efflux capacity and cardiovascular disease (CVD). The efflux of cholesterol from cells to HDL can occur by several mechanisms, including unmediated aqueous diffusion and ABCA1, ABCG1 and SR-BI specifically mediated process. We developed a high throughput assay to measure pathway specific HDL efflux capacity using BHK cells expressing inducible ABCA1, ABCG1, or SR-BI in 96-well plate format. We found that ABCA1-mediated cholesterol efflux in BHK cells correlated significantly with that of J774 macrophages when apoA-I, HDL or 2% apoB-depleted serum were used as acceptors (R2=0.98 to 0.99, p<0.0001). Compared with J774 macrophages, ABCA1-mediated efflux using BHK cells is more sensitive, consistent and has better reproducibility (Intro-assay CV=3.0%, R2=0.99; Inter assay CV=3.2%, R2=0.98). The consistence and reproducibility for ABCG1 and SR-BI mediated cholesterol efflux were also excellent as judged by intro-assay and inter-assay CV and R2. When pathway...