Identification of upregulators of human ATP-binding cassette transporter A1 via high-throughput screening of a synthetic and natural compound library

The ATP-binding cassette trasporter A1 (ABCA1) is a membrane transporter that directly contributes tohigh-density lipoprotein (HDL) biogenesis by mediating the cellular efflux of cholesterol and phospholipids to lipid-poor apolipoprotein A-I. Therefore, identification of a novel upregulator of ABCA1 would be beneficial for atherosclerosis prevention and/or therapy because of ots pivotal role in cholesterol homeostasis and HDL metabolism. In this study, a high-throughput assay mthod for ABCA1 upregulates was developed and used for screening a synthetic and natural compound library. The cell-based high-throughput screen is conducted in a 96-well format using the human hepatoma HepG2 cells stably transfected with ABCA1 promoter-luciferase construct and calibrated in a 96-well reference ABCA1 upregulates (oxysterols, 9-cis-retinoic acid, thiazolidinediones, cyclic adenosine monophosphate, verapamil, fenofibrate, and oncostatin M). Among 2600 compounds, 4 microbial compounds (pyrromycin, aclarubin, daidzein, and pratensein) were picled up as hits by the high-throughput screening assay, and those compounds were further identified as upregulators of ABCA1 expression by real-time quantative reverse transcription-polymerase chain reaction and Western blot analysis.