Effects of carboxy-terminal truncation on human lecithin:cholesterol acyltransferase activity.

Objective: Enhancement of LCAT (lecithin:cholesterol acyltransferase) activity has possibility to be beneficial for atherosclerosis. To evaluate this concept, we characterized our novel, orally administered, small-molecule LCAT activator DS-8190a, which was created from high-throughput screening and subsequent derivatization. We also focused on its mechanism of LCAT activation and the therapeutic activity with improvement of HDL (high-density lipoprotein) functionality. Approach and Results: DS-8190a activated human and cynomolgus monkey but not mouse LCAT enzymes in vitro. DS-8190a was orally administered to cynomolgus monkeys and dose dependently increased LCAT activity (ca. 2.1-fold in 3 mg/kg group on day 7), resulting in HDL cholesterol elevation without drastic changes of non-HDL cholesterol. Atheroprotective effects were then evaluated using Ldl-r KO × hLcat Tg mice fed a Western diet for 8 weeks. DS-8190a treatment achieved significant reduction of atherosclerotic lesion area (48.3% reduction in 10 mg/kg treatment group). Furthermore, we conducted reverse cholesterol transport study using Ldl-r KO × hLcat Tg mice intraperitoneally injected with J774A.1 cells loaded with [ 3 H]-cholesterol and confirmed significant increases of [ 3 H] count in plasma (1.4-fold) and feces (1.4-fold on day 2 and 1.5-fold on day3) in the DS-8190a–treated group. With regard to the molecular mechanism involved, direct binding of DS-8190a to human LCAT protein was confirmed by 2 different approaches: affinity purification by DS-8190a–immobilized beads and thermal shift assay. In addition, the candidate binding site of DS-8190a in human LCAT protein was identified by photoaffinity labeling. Conclusions: This study demonstrates the potential of DS-8190a as a novel therapeutic for atherosclerosis. This is also the first report describing that a small-molecule direct LCAT activator achieved HDL cholesterol elevation in monkey and reduction of atherosclerotic lesion area with enhanced HDL function in rodent.

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Reverse cholesterol transport from fibroblasts to high density lipoproteins: computer solutions of a kinetic model

Canadian Journal of Biochemistry ◽

10.1139/o81-081 ◽

1981 ◽

Vol 59 (8) ◽

pp. 586-592 ◽

Cited By ~ 4

Author(s):

Roy B. Verdery

Keyword(s):

Theoretical Calculations ◽

Density Lipoprotein ◽

High Density ◽

High Density Lipoproteins ◽

Computer Integration ◽

Lecithin:Cholesterol Acyltransferase ◽

Cholesterol Removal ◽

Acyltransferase Activity ◽

Direct Experiment ◽

Peripheral Cells

A model for cholesterol balance between fibroblasts and high density lipoproteins which includes first steps in cholesterol egress is proposed. Kinetic solutions of this model, obtained by digital computer integration of associated differential equations, showed that 15-fold variations in high density lipoprotein levels might be expected to cause less than 8% change in cell cholesterol and twofold variations in lecithin:cholesterol acyltransferase activity might be expected to cause less than 10% change in cell cholesterol. These theoretical calculations are limited by deficiencies in the model. However, they can be used as adjuncts to direct experiment to evaluate the hypothesis that high density lipoproteins and lecithin:cholesterol acyltransferase are involved in cholesterol removal from peripheral cells.

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