出版社：American Society for Biochemistry and Molecular Biology
摘要：We have identified a series of potent cholesteryl ester transferprotein (CETP) inhibitors, one member of which, torcetrapib,is undergoing phase 3 clinical trials. In this report, we demonstratethat these inhibitors bind specifically to CETP with 1:1 stoichiometryand block both neutral lipid and phospholipid (PL) transferactivities. CETP preincubated with inhibitor subsequently boundboth cholesteryl ester and PL normally; however, binding oftriglyceride (TG) appeared partially reduced. Inhibition bytorcetrapib could be reversed by titration with both nativeand synthetic lipid substrates, especially TG-rich substrates,and occurred to an equal extent after long or short preincubations.The reversal of TG transfer inhibition using substrates containingTG as the only neutral lipid was noncompetitive, suggestingthat the effect on TG binding was indirect. Analysis of theCETP distribution in plasma demonstrated increased binding toHDL in the presence of inhibitor. Furthermore, the degree towhich plasma CETP shifted from a free to an HDL-bound statewas tightly correlated to the percentage inhibition of CE transferactivity. The finding by surface plasmon resonance that torcetrapibincreases the affinity of CETP for HDL by 5-fold likely representsa shift to a binding state that is nonpermissive for lipid transfer.In summary, these data are consistent with a mechanism wherebythis series of inhibitors block all of the major lipid transferfunctions of plasma CETP by inducing a nonproductive complexbetween the transfer protein and HDL.Supplementary key words lipid transfer • high density lipoprotein • atherosclerosis • cardiovascular disease
Abbreviations: apoA-I, apolipoprotein A-I BPI, bactericidal/permeability-increasing protein; CE, cholesteryl ester; CETP, cholesteryl ester transfer protein; FC, free cholesterol; FPLC, fast-protein liquid chromatography; HDL-C, high density lipoprotein cholesterol; LDL-C, low density lipoprotein cholesterol; Mr, apparent molecular weight; PC, phosphatidylcholine; PL, phospholipid; PLTP, phospholipid transfer protein; SPR, surface plasmon resonance; TC, total cholesterol; TG, triglyceride; WT, wild-type
5-fold likely represents a shift to a binding state that is nonpermissive for lipid transfer. In summary, these data are consistent with a mechanism whereby this series of inhibitors block all of the major lipid transfer functions of plasma CETP by inducing a nonproductive complex between the transfer protein and HDL.
Supplementary key words lipid transfer • high density lipoprotein • atherosclerosis • cardiovascular disease
Abbreviations: apoA-I, apolipoprotein A-I BPI, bactericidal/permeability-increasing protein; CE, cholesteryl ester; CETP, cholesteryl ester transfer protein; FC, free cholesterol; FPLC, fast-protein liquid chromatography; HDL-C, high density lipoprotein cholesterol; LDL-C, low density lipoprotein cholesterol; Mr, apparent molecular weight; PC, phosphatidylcholine; PL, phospholipid; PLTP, phospholipid transfer protein; SPR, surface plasmon resonance; TC, total cholesterol; TG, triglyceride; WT, wild-type
