ANALYSIS OF GENE EXPRESSION PROFILE IN MACROPHAGES TREATED WITH OXIDIZED LDL AND THE ACAT INHIBITOR AVASIMIBE

Abstract
In a recent article (Llaverias et al., Eur J Pharmacol 451:11-17, 2002) we demonstrated that the ACAT inhibitor avasimibe reduces the intracellular content of cholesteryl esters in THP-1 macrophages. In the present work, we have investigated the effects of avasimibe on the pattern of gene expression in the above mentioned cells, to identify novel genes regulated by this agent that may be involved in atherosclerosis development. To this end, we have used ADNc arrays that allow the simultaneous screening of a huge number of genes. Among the results obtained, it is of special interest the increase in the ARNm levels of FABP4 detected after exposure of the cells to oxidized-LDL, which is attenuated when the cells were treated in the presence of avasimibe. It has been described that the absence of FABP4 in macrophages protects apoE-deficient mice from atherosclerosis development. Therefore, the inhibition of FABP4 expression in macrophages may represent a novel mechanism of action that could explain the direct antiatherosclerotic effects of avasimibe, impairing the accumulation of cholesterol in these cells.

Key words
Macrophages, oxidized ldl, avasimibe, gene expression, arrays

Bibliografía del artículo

1. Singh BK, Mehta JL. Management of dyslipidemia in the primary prevention of coronary heart disease. Curr Opin Cardiol 2002;17:503-511.
2. Executive Summary of the Third Report of the National Cholesterol Education Program (NCEP) Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults (Adult Treatment Panel III). JAMA 2001;285:2486-2497.
3. Maron DJ, Fazio S, McRae FL. Current perspectives on statins. Circulation 2000;101:207-213.
4. Pearson TA, Laurora I, Chu H et al. The Lipid Treatment Assessement Project (L-TAP): a multicenter survey to evaluate the percentages of dyslipidemic patients receiving lipid-lowering therapy and achieving low-density lipoprotein cholesterol goals. Arch Intern Med 2000;160:459-467.
5. Ross R. The pathogenesis of atherosclerosis: an update. N Engl J Med 1986;314:488-500.
6. Lee HT, Sliskovic DR, Picard JA, et al. Inhibitors of acyl-CoA: cholesterol O-acyl transferase (ACAT) as hypocholesterolemic agents. CI-1011: an acyl sulfamate with unique cholesterol-lowering activity in animals fed noncholesterol- supplemented diets. J Med Chem 1996;39:5031-5034.
7. Llaverias G, Laguna JC, Alegret M. Pharmacology of the ACAT inhibitor avasimibe (CI-1011). Cardiovasc Drug Rev 2003.
8. Llaverias G, Jove M, Vazquez-Carrera M, et al. Avasimibe and atorvastatin synergistically reduce cholesteryl ester content in THP-1 macrophages. Eur J Pharmacol 2002;451:11-17.
9. Warner GJ, Stoudt G, Bamberger M, et al. Cell toxicity induced by inhibition of acyl coenzyme A:cholesterol acyltransferase and accumulation of unesterified cholesterol. J Biol Chem 1995;270:5772-5778.
10. Kellner-Weibel G, Jerome WG, Small D et al. Effects of intracellular free cholesterol accumulation on macrophage viability: a model for foam cell death. Arterioscler Thromb Vasc Biol 1998;18:423-431.
11. Perrey S, Legendre C, Matsuura A, et al. Preferential pharmacological inhibition of macrophage ACAT increases plaque formation in mouse and rabbit models of atherogenesis. Atherosclerosis 2001;155:359-370.
12. Li AC, Glass CK. The macrophage foam cell as a target for therapeutic intervention. Nat Med 2002;8:1235-1242.
13. Auwerx J. The human leukemia cell line THP-1: a multifaceted model for the study of monocyte-macrophage differentiation. Experientia 1991;47:22-31.
14. Andersson T, Boräng S, Larsson M, et al. Novel candidate genes for atherosclerosis are identified by representational difference analysis-based transcript profiling of cholesterol-loaded macrophages. Pathobiology 2001;69:304-314.
15. Dhaliwal BS, Steinbrecher UP. Scavenger receptors and oxidized low density lipoproteins. Clin Chim Acta 1999;286:191-205.
16. Tsukamoto K, Kinoshita M, Kojima K, et al. Synergically increased expression of CD36, CLA-1 and CD68, but not of SR-A and LOX-1, with the progression to foam cells from macrophages. J Atheroscler Thromb 2002;9:57-64.
17. Cabrero A, Cubero M, Llaverias G, et al. Differential effects of peroxisome proliferator-activated receptor activators on the ARNm level of genes involved in lipid metabolism in primary human monocyte-derived macrophages. Metabolism 2003;52:652-657.
18. Fu Y, Luo N, Lopes-Virella M F. Oxidized LDL induces the expression of ALBP/aP2 ARNm and protein in human THP-1macrophages. J Lipid Res 2000;41:2017-2023.
19. Sun L, Nicholson AC, Hajjar DP, et al. Adipogenic differentiating agents regulate expression of fatty acid binding protein and CD36 in the J744 macrophage cell line. J Lipid Res 2003;44:1877-1886.
20. Makowski L, Boord JB, Maeda K, et al. Lack of macrophage fatty-acid-binding protein aP2 protects mice deficient in apolipoprotein E against atherosclerosis. Nat Med 2001;7:699-705.
21. Fidge N. High density lipoprotein receptors, binding proteins, and ligands. J Lipid Res 1999;40:187-201.
22. Chiu DS, Oram JF, LeBoeuf RC et al. High-density lipoprotein-binding protein (HBP)/vigilin is expressed in human atherosclerotic lesions and colocalizes with apolipoprotein E. Arterioscler Thromb Vasc Biol 1997;-2350.
23. Zhang W-Y, Gaynor PM, Kruth HS. Apolipoprotein E produced by human monocyte-derived macrophages mediates cholesterol efflux that occurs in the absence of added cholesterol acceptors. J Biol Chem 1996;271:28641-28646.
24. Bellosta S, Mahley RW, Sanan DA, Murata J, Newland DL, Taylor JM, Pitas RE. Macrophage-specific expression of human apolipoprotein E reduces atherosclerosis in hypercholesterolemic apolipoprotein E-null mice. J Clin Invest 1995;96:2170-2179.
25. Mazzone T, Basheeruddin K. Dissociated regulation of macrophage LDL receptor and apolipoprotein E gene expression by sterol. J Lipid Res 1991;32:507-514.
26. Castilho LN, Chamberland A, Boulet L, et al. Effect of atorvastatin on ApoE and ApoC-I synthesis and secretion by THP-1 macrophages. J Cardiovasc Pharmacol 2003;42:251-257.
27. O'Brien ER, Garvin MR, Dev R, et al. Angiogenesis in human coronary atherosclerotic plaques. Am J Pathol 1994;145:883-894.
28. Lijnen HR. Plasmin and Matrix Metalloproteinases in Vascular Remodeling. Thromb Haemost 2001;86:324-333.
29. Winberg JO, Kolset SO, Berg E, Uhlin-Hansen L. Macrophages secrete matrix metalloproteinase 9 covalently linked to the core protein of chondroitin sulphate proteoglycans. J Mol Biol 2000;304:669-680.
30. Death AK, Fisher EJ, McGrath KCY, et al. High glucose alters matrix metalloproteinase expression in two key vascular cells: potential impact on atherosclerosis in diabetes. Atherosclerosis 2003;168:263-269.