Identifying Natural Derived Upregulators of Human ApoA-I Expression via a Cell-Based Drug Screening System

Abstract

Apolipoprotein A-I (apoA-I), the major protein component of high-density lipoprotein, is instrumental in promoting efflux of cholesterol from extrahepatic tissues to the liver. It has been proposed that upregulation of apoA-I gene expression could have anti-atherosclerosis effects. For the purpose of screening human apoA-I expression upregulators, we established a cell-based drug screening model in vitro to identifying the effects of natural derived upregulators of apoA-I. In the work, human apoA-I promoter gene was cloned into pGL3B-neo vector containing luciferase gene and neomycin resistance gene. The recombinant reporter gene vector pGL3B-neo/apo was transfected into HepG2 cells, and therefore the stable cell line SApoA-I was obtained. These cells were treated with extracts from traditional Chinese herbs. The luciferase activities were detected to identify which ones can activate apoA-I promoter. Baicalein extracted from dried roots of Scutellaria baicalensis Georgi (Labiatae, Scutellaria) showed significant dose-dependent upregulatory activity in cell model, which might become an effective basic compound for developing novel HDL-raising drugs because of its effects on proteins involved in reverse cholesterol transport.

Keywords:

• ApoA-I
• baicalein
• drug screening
• HDL
• reverse cholesterol transport

Acknowledgment

This work was mainly supported by Shanghai Comman Pharmaceutical Co., Ltd. We are greatful to G.J. Zhang, L.M. Wang, and J.X. Cao for their excellent technical assistance.