Scavenger receptor class B type I (SR-BI) is the high-affinity high-density lipoprotein (HDL) receptor, and CLA-1 is the human homologue of the murine SR-BI. CLA-1/SR-BI receptor has been suggested as a new preventative and/or therapeutic target for atherosclerosis due to its pivotal role in overall HDL cholesterol (HDL-C) metabolism and its antiatherogenic activity in vivo. To search for active compounds that can increase CLA-1 transcription, a novel cell-based assay was developed for application in high-throughput screening (HTS). Human hepatoma HepG2 cells were transfected with a CLA-1-promoter-luciferase reporter gene construct, and the stable transfected cell line was selected and named CLAp-LUC HepG2. With rosiglitazone as a positive control, this stable cell line was used to establish a specific CLA-1 gene expression assay in a 96-well microplate format. The evaluating parameter Z' value of 0.64 showed that this cell-based HTS assay was robust and reliable. Screening of 6000 microbial secondary metabolite crude extracts identified 8 positive strains. Between 2 identified CLA-1 up-regulators produced by actinomycete strain 04-4776, 4776B may stimulate not only the expression of CLA-1 on the transcriptional and translational levels but also the activity of CLA-1 to uptake the HDL-C in HepG2 cells. The active compounds originated from this HTS assay may be developed to drug candidates or lead compounds for new antiatherosclerosis agents.
Lewis GF, Rader DJ: New insights into the regulation of HDL metabolism and reverse cholesterol transport. Circ Res2005;96:1221-1232.
2.
Acton S, Rigotti A, Landschulz KT, Xu SZ, Hobbs HH, Krigger M: Identification of scavenger receptor SR-BI as a high density lipoprotein receptor. Science1996;271:517-520.
3.
Calvo D, Vega MA: Identification, primary structure, and distribution of CLA-1, a novel member of the CD36/LIMPII gene family. J Biol Chem1993;268:18929-18935.
4.
Cao GQ, Garcia CK, Wyne KL, Schultz RA, Parker KL, Hobbs HH: Structure and localization of the human gene encoding SR-BI/CLA-1. J Biol Chem1997;272:33068-33076.
5.
Ji Y, Jian B, Wang N, Sun Y, Moya ML, Phillips MC, et al: Scavenger receptor BI promotes high density lipoprotein-mediated cellular cholesterol efflux. J Biol Chem1997;272:20982-20985.
6.
Zhang Y, Da Silva JR, Reilly M, Billheimer JT, Rothblat GH, Rader DJ: Hepatic expression of scavenger receptor class B type I (SR-BI) is a positive regulator of macrophage reverse cholesterol transport in vivo. J Clin Invest2005;115:2870-2874.
7.
Trigatti B, Covey S, Rizvi A: Scavenger receptor class B type I in high-density lipoprotein metabolism, atherosclerosis and heart disease: lessons from gene-targeted mice. Biochem Soc Trans2004;32(pt 1):116-120.
8.
Acton SL, Kozarsky KF, Rigotti A: The HDL receptor SR-BI: a new therapeutic target for atherosclerosis?Mol Med Today1999;5:518-524.
9.
Osgood D, Corella D, Demissie S, Cupples LA, Wilson PW, Meigs JB, et al: Genetic variation at the scavenger receptor class B type I gene locus determines plasma lipoprotein concentrations and particle size and interacts with type 2 diabetes: the Framingham study. J Clin Endocrinol Metab2003;88:2869-2879.
10.
Hsu LA, Ko YL, Wu S, Teng MS, Peng TY, Chen CF, et al: Association between a novel 11-base pair deletion mutation in the promoter region of the scavenger receptor class B type I gene and plasma HDL cholesterol levels in Taiwanese Chinese. Arterioscler Thromb Vasc Biol2003;23:1869-1874.
11.
Rodriguez-Esparragon F, Rodriguez-Perez JC, Hemandez-Trujillo Y, Macias-Reyes A, Medina A, Caballero A, et al: Allelic variants of the human scavenger receptor class B type I and paraoxonase I on coronary heart disease: genotype-phenotype correlations. Arterioscler Thromb Vasc Biol2005;25:854-860.
12.
Liu XH, Hong B, Wang LF, Yang Y, Si SY, Li Y: Establishment of a drug screening model for identifying up-regulator of human high-density lipoprotein receptor. Acta Acad Med Sin2004;26:354-358.
13.
Malerod L, Sporstol M, Juvet LK, Mousavi A, Gjoen T, Berg T: Hepatic scavenger receptor class B, type I is stimulated by peroxisome proliferatorsactivated receptor α and hepatocyte nuclear factor 4α. Biochem Bioph Res Commun2003;305:557-565.
Huang ZP, Inazu A, Kawashiri M, Nohara A, Higashikata T, Mabuchi H: Dual effects on HDL metabolism by cholesteryl ester transfer protein inhibition in HepG2 cells. Am J Physiol Endocrinol Metab2003;284: E1210-E1219.
16.
Marone M, Mozzetti S, Ritis DD, Pierelli L, Scambia G: Semiquantitative RT-PCR analysis to assess the expression levels of multiple transcripts from the same sample. Biol Proced Online2001;3:19-25.
17.
Zhang JH, Chung TDY, Oldenburg KR: A simple statistical parameter for use in evaluation and validation of high throughput screening assays. J Biomol Screen1999;4:67-73.
18.
Shah PK: Emerging non-statin LDL-lowering therapies for dyslipidemia and atherosclerosis. Rev Cardiovasc Med2003;4:136-141.
19.
Price MJ, Shah PK: New strategies in managing and preventing atherosclerosis: focus on HDL. Rev Cardiovasc Med2002;3:129-137.
20.
Trigatti BL, Krieger M, Rigotti A: Influence of the HDL receptor SR-BI on lipoprotein metabolism and atherosclerosis. Arterioscler Thromb Vasc Biol2003;23:1732-1738.
21.
Mizutani T, Yamada K, Mineqishi T, Miyamoto K: Transcriptional regulation of rat scavenger receptor class B type I gene. J Biol Chem2000;275: 22512-22519.
22.
Treguier M, Doucet C, Moreau M, Dachet C, Thillet J, Chapman MJ, et al: Transcription factor sterol regulatory element binding protein 2 regulates scavenger receptor cla-1 gene expression. Arterioscler Thromb Vasc Biol2004;24:2358-2364.
23.
Schoonjans K, Annicotte JS, Huby T, Botrugno OA, Fayard E, Ueda Y, et al: Liver receptor homolog 1 controls the expression of the scavenger receptor class B type I. EMBO Rep2002;3:1181-1187.
24.
Sporstol M, Tapia G, Malerod L, Mousavi SA, Berg T: Pregnane X receptor-agonists down-regulate hepatic ATP-binding cassette transporter A1 and scavenger receptor class B type I. Biochem Biophys Res Commun2005;331:1533-1541.
25.
Lambert G, Amar MJ, Guo G, Brewer HB Jr, Gonzalez FJ, Sinal CJ: The farnesoid X-receptor is an essential regulator of cholesterol homeostasis. J Biol Chem2003;278:2563-2570.
26.
Malerod L, Juvet LK, Hanssen-Bauer A, Eskild W, Berg T: Oxysterolactivated LXRalpha/RXR induces hSR-BI-promoter activity in hepatoma cells and preadipocytes. Biochem Biophys Res Commun2002;299:916-923.
27.
Martens FM, Visseren FL, Lemay J, Koning EJ, Rabelink TJ: Metabolic and additional vascular effects of thiazolidinediones. Drugs2002;62:1463-1480.
28.
Webb NR, Connell PM, Graf GA, Smart EJ, Villiers WJS, Beer FC, et al: SR-BII, an isoform of the scavenger receptor BI containing an alternate cytoplasmic Tail, mediates lipid transfer between high density lipoprotein and cells. J Biol Chem1998;273:15241-15248.
29.
Han CH, Lee MN: Topology of scavenger receptor class B type I (SR-BI) on brush border membrane. J Vet Sci2002;3:265-272.
30.
Cassidy A, Hooper L: Phytoestrogens and cardiovascular disease. J Br Menopause Soc2006;12:49-56.
31.
Cassidy A, Albertazzi P, Lise Nielsen I, Hall W, Williamson G, Tetens I, et al: Critical review of health effects of soyabean phyto-oestrogens in post-menopausal women. Proc Nutr Soc2006;65:76-92.
32.
Sharma RD: Effect of various isoflavones on lipid levels in Triton-treated rats. Atherosclerosis1979;33:371-375.
