Managing Atherosclerosis by Modulating HDL Function

项目总结/摘要 动脉粥样硬化是全世界人类死亡的主要原因。一直以来， 开发这种疾病的新疗法，其通过正交作用机制发挥作用， 可用的药物。一个有前途的策略是增强高密度脂蛋白（HDL）的功能。HDLs 促进胆固醇逆向转运（RCT），将多余的胆固醇从外周组织转移到肝脏 以供淘汰。这项拟议中的研究得到了最近强有力的进展的支持， 超分子策略改善体内HDL功能以对抗动脉粥样硬化。 拟议的研究建立在我们的研究计划的成功基础上，由NHLBI R 01拨款资助， 在过去的八年里尽管载脂蛋白模拟肽领域取得了实质性进展，包括 在1期和2期人体临床试验中评价几种候选药物， 与线性肽相关的典型缺点是提高HDL的主要障碍， 通过临床调节肽。我们提出的研究旨在开发一类新的化学型 其可以概括螺旋脂蛋白模拟物的功能属性，但没有其固有的局限性。 我们已经确定，适当设计的八残基自组装环状D，L-a-肽是 可重塑人和小鼠血浆HDL并提高胆固醇水平的有效HDL调节剂 从巨噬细胞流出。这些肽特异性地增加前β HDL颗粒的水平 （HDL的亚种被认为是最抗动脉粥样硬化的），降低LDL-胆固醇和甘油三酯水平， 并在小鼠疾病模型中促进抗炎作用，同时预防动脉粥样硬化。 环状D，L-a-肽的非生物结构克服了通常与生物活性相关的许多缺点。 线性肽，例如低血清/血浆稳定性和高生产成本等。 拟议研究的具体目标1和2涉及i）实施一系列基于机制的 功能性生物测定和生物物理测定，以优化和更好地表征先导化合物的作用模式 ii）在两种化合物中建立所选环肽的体内药理学、毒理学和功效， 领先的动脉粥样硬化小鼠模型。拟议研究的具体目标3是基于一个意想不到的， 我们在最近的研究中发现了一个惊人的现象。我们已经发现三氟乙酸盐（TFA）， 口服或肠胃外给药，引起血浆胆固醇水平的剂量依赖性降低， 体内动脉粥样硬化的发展。这一发现的影响可能是广泛的，因为 几乎所有在不同生物环境中使用的合成肽都含有TFA抗衡离子， 通过制备型HPLC纯化。因此，必须研究TFA对体外和体内细胞代谢的影响。 特点和理解。我们提出了一系列基于假设的体外和体内研究来定义 观察到的TFA介导的抗动脉粥样硬化作用的机制和一般性。

PROJECT SUMMARY/ABSTRACT Atherosclerosis is the leading cause of human mortality worldwide. There has been a great interest in developing novel therapeutics for this disease that function via an orthogonal mechanism of action to currently available drugs. One promising strategy is to enhance the function of high-density lipoproteins (HDLs). HDLs facilitate reverse cholesterol transport (RCT) to transfer excess cholesterol from peripheral tissues to the liver for elimination. The proposed research, supported by strong recent progress, seeks to advance a novel supramolecular strategy for improving HDL function in vivo to combat atherosclerosis. The proposed studies build on the successes of our research program, funded by an NHLBI R01 grant over the past eight years. Despite substantial progress in the field of apolipoprotein mimetic peptides, including evaluation of several candidates in phase 1 and 2 human clinical trials, the inherent pharmacological shortcomings typically associated with linear peptides have been a major impediment to advancing HDL- modulating peptides through the clinic. Our proposed research seeks to develop a novel class of chemotypes that can recapitulate the functional attributes of helical lipoprotein mimetics, but without their inherent limitations. We have established that appropriately designed eight-residue self-assembling cyclic D,L-a-peptides are effective HDL modulating agents that can remodel human and mouse plasma HDLs and enhance cholesterol efflux from macrophage cells. These peptides specifically increase the level of pre-beta HDL particles (subspecies of HDLs considered to be the most anti-atherogenic), reduce LDL-cholesterol and triglyceride levels, and promote anti-inflammatory effects with concomitant prevention of atherosclerosis in mouse disease models. The abiotic structure of cyclic D,L-a-peptides overcomes many of the shortcomings typically associated with linear peptides, such as low serum/plasma stability and high production costs, among others. Specific aims 1 and 2 of the proposed research involve i) implementing a series of mechanism-based functional bioassays and biophysical assays to optimize and better characterize the mode of action of the lead compounds, and ii) establishing in vivo pharmacology, toxicology, and efficacy of selected cyclic peptides in two leading mouse models of atherosclerosis. Specific aim 3 of the proposed research is based on an unexpected, remarkable observation made in the course of our recent studies. We have discovered that trifluoroacetate (TFA), administered orally or parenterally, causes dose-dependent reductions in plasma cholesterol levels and prevents the development of atherosclerosis in vivo. The implications of this discovery are potentially broad because nearly all synthetic peptides, employed across diverse biological settings, contain TFA counterions resulting from purification by preparative HPLC. As such, the effects of TFA on cellular metabolism in vitro and in vivo must be characterized and understood. We propose a series of hypothesis-based in vitro and in vivo studies to define the mechanism and generality of the observed TFA-mediated anti-atherosclerosis effects.