Advertisement

A selective ACAT-1 inhibitor, K-604, suppresses fatty streak lesions in fat-fed hamsters without affecting plasma cholesterol levels

      Abstract

      Background

      Acyl-coenzyme A:cholesterol O-acyltransferase-1 (ACAT-1), a major ACAT isozyme in macrophages, plays an essential role in foam cell formation in atherosclerotic lesions. However, whether pharmacological inhibition of macrophage ACAT-1 causes exacerbation or suppression of atherosclerosis is controversial.

      Methods and results

      We developed and characterized a novel ACAT inhibitor, K-604. The IC50 values of K-604 for human ACAT-1 and ACAT-2 were 0.45 and 102.85 μmol/L, respectively, indicating that K-604 is 229-fold more selective for ACAT-1. Kinetic analysis indicated that the inhibition was competitive with respect to oleoyl-coenzyme A with a Ki value of 0.378 μmol/L. Exposure of human monocyte-derived macrophages to K-604 inhibited cholesterol esterification with IC50 of 68.0 nmol/L. Furthermore, cholesterol efflux from THP-1 macrophages to HDL3 or apolipoprotein A-I was enhanced by K-604. Interestingly, administration of K-604 to F1B hamsters on a high-fat diet at a dose of ≥1 mg/kg suppressed fatty streak lesions without affecting plasma cholesterol levels.

      Conclusions

      K-604, a potent and selective inhibitor of ACAT-1, suppressed the development of atherosclerosis in an animal model without affecting plasma cholesterol levels, providing direct evidence that pharmacological inhibition of ACAT-1 in the arterial walls leads to suppression of atherosclerosis.

      Keywords

      To read this article in full you will need to make a payment

      Purchase one-time access:

      Academic & Personal: 24 hour online accessCorporate R&D Professionals: 24 hour online access
      One-time access price info
      • For academic or personal research use, select 'Academic and Personal'
      • For corporate R&D use, select 'Corporate R&D Professionals'

      Subscribe:

      Subscribe to Atherosclerosis
      Already a print subscriber? Claim online access
      Already an online subscriber? Sign in
      Institutional Access: Sign in to ScienceDirect

      References

        • Buhman K.F.
        • Accad M.
        • Farese R.V.
        Mammalian acyl-CoA:cholesterol acyltransferases.
        Biochim Biophys Acta. 2000; 1529: 142-154
        • Chang T.Y.
        • Chang C.C.
        • Lin S.
        • et al.
        Roles of acyl-coenzyme A:cholesterol acyltransferase-1 and -2.
        Curr Opin Lipidol. 2001; : 289-296
        • Chang T.Y.
        • Chang C.C.
        • Cheng D.
        Acyl-coenzyme A:cholesterol acyltransferase.
        Annu Rev Biochem. 1997; 66: 613-638
        • Chang C.C.
        • Huh H.Y.
        • Cadigan K.M.
        • Chang T.Y.
        Molecular cloning and functional expression of human acyl-coenzyme A:cholesterol acyltransferase cDNA in mutant Chinese hamster ovary cells.
        J Biol Chem. 1993; 268: 20747-20755
        • Oelkers P.
        • Behari A.
        • Cromley D.
        • Billheimer J.T.
        • Sturley S.L.
        Characterization of two human genes encoding acyl coenzyme A:cholesterol acyltransferase-related enzymes.
        J Biol Chem. 1998; 273: 26765-26771
        • Sakashita N.
        • Miyazaki A.
        • Takeya M.
        • et al.
        Localization of human acyl-coenzyme A:cholesterol acyltransferase-1 (ACAT-1) in macrophages and in various tissues.
        Am J Pathol. 2000; 156: 227-236
        • Parini P.
        • Davis M.
        • Lada A.T.
        • et al.
        ACAT2 is localized to hepatocytes and is the major cholesterol-esterifying enzyme in human liver.
        Circulation. 2004; 110: 2017-2023
        • Chang C.C.
        • Sakashita N.
        • Ornvold K.
        • et al.
        Immunological quantitation and localization of ACAT-1 and ACAT-2 in human liver and small intestine.
        J Biol Chem. 2000; 275: 28083-28092
        • Miyazaki A.
        • Sakashita N.
        • Lee O.
        • et al.
        Expression of ACAT-1 protein in human atherosclerotic lesions and cultured human monocytes-macrophages.
        Arterioscler Thromb Vasc Biol. 1998; 18: 1568-1574
        • Wang H.
        • Germain S.J.
        • Benfield P.P.
        • Gillies P.J.
        Gene expression of acyl-coenzyme-A:cholesterol-acyltransferase is upregulated in human monocytes during differentiation and foam cell formation.
        Arterioscler Thromb Vasc Biol. 1996; 16: 809-814
        • Streja L.
        • et al.
        Factors affecting low-density lipoprotein and high-density lipoprotein cholesterol response to pravastatin in the West Of Scotland Coronary Prevention Study (WOSCOPS).
        Am J Cardiol. 2002; 90: 731-736
        • Miyazaki A.
        • Sakai M.
        • Sakamoto Y.
        • Horiuchi S.
        Acyl-coenzyme A:cholesterol acyltransferase inhibitors for controlling hypercholesterolemia and atherosclerosis.
        Curr Opin Invest Drugs. 2003; 4: 1095-1099
        • Ong H.T.
        The statin studies: from targeting hypercholesterolaemia to targeting the high-risk patient.
        QJM. 2005; 98: 599-614
        • Fazio S.
        • Major A.S.
        • Swift L.L.
        • et al.
        Increased atherosclerosis in LDL receptor-null mice lacking ACAT1 in macrophages.
        J Clin Invest. 2001; 107: 163-171
        • Chang C.C.
        • Chen J.
        • Thomas M.A.
        • et al.
        Regulation and immunolocalization of acyl-coenzyme A:cholesterol acyltransferase in mammalian cells as studied with specific antibodies.
        J Biol Chem. 1995; 270: 29532-29540
        • Chang C.C.
        • Lee C.Y.
        • Chang E.T.
        • et al.
        Recombinant acyl-CoA:cholesterol acyltransferase-1 (ACAT-1) purified to essential homogeneity utilized cholesterol in mixed micelles or in vesicles in a highly cooperative manner.
        J Biol Chem. 1998; 273: 35132-35141
        • Wilde R.G.
        • Billheimer J.T.
        • Germain S.J.
        • et al.
        ACAT inhibitors derived from hetero-Diels–Alder cycloadducts of thioaldehydes.
        Bioorg Med Chem. 1996; 4: 1493-1513
        • Nicolosi R.J.
        • Wilson T.A.
        • Krause B.R.
        The ACAT inhibitor, CI-1011 is effective in the prevention and regression of aortic fatty streak area in hamsters.
        Atherosclerosis. 1998; 137: 77-85
        • Kowala M.C.
        • Nunnari J.J.
        • Durham S.K.
        • Nicolosi R.J.
        Doxazosin and cholestyramine similarly decrease fatty streak formation in the aortic arch of hyperlipidemic hamsters.
        Atherosclerosis. 1991; 91: 35-49
        • Bocan T.M.
        • Mueller S.B.
        • Uhlendorf P.D.
        • Newton R.S.
        • Krause B.R.
        Comparison of CI-976, an ACAT inhibitor, and selected lipid-lowering agents for antiatherosclerotic activity in iliac-femoral and thoracic aortic lesions. A biochemical, morphological, and morphometric evaluation.
        Arterioscler Thromb. 1991; 11: 1830-1843
        • Ioriya K.
        • Noguchi T.
        • Muraoka M.
        • et al.
        Effect of SMP-500, a novel acyl-CoA:cholesterol acyltransferase inhibitor, on the cholesterol esterification and its hypocholesterolemic properties.
        Pharmacology. 2002; 65: 18-25
        • Rival Y.
        • Junquero D.
        • Bruniquel F.
        • et al.
        Anti-atherosclerotic properties of the acyl-coenzyme A:cholesterol acyltransferase inhibitor F 12511 in casein-fed New Zealand rabbits.
        J Cardiovasc Pharmacol. 2002; 39: 181-191
        • Aragane K.
        • Fujinami K.
        • Kojima K.
        • Kusunoki J.
        ACAT inhibitor F-1394 prevents intimal hyperplasia induced by balloon injury in rabbits.
        J Lipid Res. 2001; 42: 480-488
        • Bocan T.M.
        • Krause B.R.
        • Rosebury W.S.
        • et al.
        The ACAT inhibitor avasimibe reduces macrophages and matrix metalloproteinase expression in atherosclerotic lesions of hypercholesterolemic rabbits.
        Arterioscler Thromb Vasc Biol. 2000; 20: 70-79
        • 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
        • Tabas I.
        Consequences of cellular cholesterol accumulation: basic concepts and physiological implications.
        J Clin Invest. 2002; 110: 905-911
        • Bernard D.W.
        • Rodoriguez A.
        • Rothblat G.H.
        • Glick J.M.
        Influence of high density lipoprotein on esterified cholesterol stores in macrophages and hepatoma cells.
        Arteriosclerosis. 1990; 10: 135-144
        • Rodriguez A.
        • Bachorik P.S.
        • Wee S.B.
        Novel effects of the acyl-coenzyme A:cholesterol acyltransferase inhibitor 58-035 on foam cell development in primary human monocyte-derived macrophages.
        Arterioscler Thromb Vasc Biol. 1999; 19: 2199-2206
        • Sugimoto K.
        • Tsujita M.
        • Wu C.A.
        • Suzuki K.
        • Yokoyama S.
        An inhibitor of acyl-CoA:cholesterol acyltransferase increases expression of ATP-binding cassette transporter A1 and thereby enhances the ApoA-I-mediated release of cholesterol from macrophages.
        Biochim Biophys Acta. 2004; 1636: 69-76
        • Tradif J.C.
        • Gregoire J.
        • L’Allier
        • et al.
        Avasimibe and progression of lesions on ultrasound (A-PLUS) investigators. Effects of the acyl coenzyme A:cholesterol acyltransferase inhibitor avasimibe on human atherosclerotic lesions.
        Circulation. 2004; 110: 3372-3377
        • Nissen S.E.
        • Tuzcu E.M.
        • Brewer H.B.
        • et al.
        ACAT Intravascular atherosclerosis treatment evaluation (ACTIVATE) investigators. Effect of ACAT inhibition on the progression of coronary atherosclerosis.
        N Engl J Med. 2006; 354: 1253-1263
        • Kharbanda R.K.
        • Wallace S.
        • Walton B.
        • et al.
        Systemic acyl-CoA:cholesterol acyltransferase inhibition reduces inflammation and improves vascular function in hypercholesterolemia.
        Circulation. 2005; 111: 804-807