Apo E mimetics reduce cholesterol and improve HDL function

描述(申请人提供)：理想的动脉粥样硬化治疗方法包括快速清除血浆胆固醇和抑制炎症途径。载脂蛋白A-I模拟肽的最新进展表明，有可能改善高密度脂蛋白的功能。本建议涉及将降低血浆载脂蛋白B-含脂蛋白的特性与改善高密度脂蛋白功能的特性相结合的方法。我们的假设是，这样的多肽不仅保留了改善高密度脂蛋白功能的特性，而且还增强了含载脂蛋白B的脂蛋白的清除，从而降低了血浆胆固醇水平。因此，我们设计了具有来自apoE的阳离子受体结合结构域的新型多肽，该结构域共价连接到一个活性的apoA-I模拟多肽结构域。我们还设计了一种单域阳离子多肽，我们在其中加入了apoA-I模拟物的脂类清除氢过氧化氢的特性。初步结果表明，这些特性增强了HepG2细胞对致动脉粥样硬化脂蛋白的摄取，并抑制了apoE基因缺失小鼠的动脉粥样硬化。它们似乎还能改善高密度脂蛋白的功能。我们有令人兴奋的结果表明，Ac-He-18A-NH2显著降低了不同血脂异常小鼠模型和WHHL兔的血浆胆固醇。初步结果还表明，该多肽具有抗炎特性。这是通过降低血浆脂质过氧化氢水平，伴随着血浆对氧磷酶活性的显着增加而发生的。在WHHL模型中，低密度脂蛋白-受体途径受到损害，因此，正如我们先前在小鼠模型中描述的那样，多肽介导的致动脉粥样硬化脂蛋白清除可能是通过细胞表面硫酸乙酰肝素蛋白多糖(HSPG)介导的途径。在第二种兔动脉粥样硬化模型中，新西兰白(NZW)兔喂食致动脉粥样硬化的饮食，单次静脉注射多肽(3 mg/kg)可显著降低血浆总胆固醇水平，持续15天。50天后对病变的EN分析显示，注射生理盐水的兔(对照组)的病变覆盖率约为50%，而注射多肽的动物几乎没有病变。因此，我们假设这些新多肽的胆固醇依赖性和非独立性都有助于这些多肽抑制动脉粥样硬化的有益作用。为了进一步研究这两种多肽的作用机制，我们提出了两个特定的目标：特定目的1：多肽对不同血脂异常的小鼠和兔模型的肝细胞和HepG2细胞摄取含apoB的脂蛋白的影响。B)载脂蛋白A-I和载脂蛋白E颗粒的变化及其抗炎特性。具体目标2：多肽对A)血浆胆固醇水平的影响，B)对动脉粥样硬化动物模型的损伤抑制，以及C)对高密度脂蛋白性质的调节。对这些新型多肽抗动脉粥样硬化特性的研究将有助于更好地了解胆固醇的动态平衡，并有望开发出可用于治疗动脉粥样硬化及其后遗症的新型治疗试剂。公共卫生相关性：动脉粥样硬化的理想治疗方法包括快速清除血浆胆固醇和抑制炎症途径。载脂蛋白A-I模拟肽的最新进展表明，有可能改善高密度脂蛋白的功能。本建议涉及将降低血浆载脂蛋白B-含脂蛋白的特性与改善高密度脂蛋白功能的特性相结合的方法。这是为了在设计的多肽中保留抗炎和降胆固醇的功能，以获得一种理想的用于治疗动脉粥样硬化和相关的脂质相关炎性疾病的多肽。

DESCRIPTION (provided by applicant): An ideal treatment for atherosclerosis would involve rapid clearance of plasma cholesterol and inhibition of inflammatory pathways. Recent advances in apoA-I mimetic peptides indicate the possibility of improving HDL functions. This proposal deals with ways of incorporating properties of lowering plasma apolipoprotein B- containing lipoproteins with properties of improving HDL function. Our hypothesis is that such peptides would not only retain properties that improve HDL functions, but also enhance the clearance of apoB-containing lipoproteins, thus lowering plasma cholesterol levels. Thus, we designed novel peptides that possesses the cationic putative receptor binding domain from apoE that is covalently linked to an active apoA-I mimetic peptide domain. We have also designed a single-domain cationic peptide to which we have incorporated the lipid hydroperoxide-scavenging properties of apoA-I mimetics. Preliminary results show that these properties enhance uptake of atherogenic lipoproteins in HepG2 cells and inhibit atherosclerosis in apoE null mice. They also appear to improve HDL function. We have exciting results to show that Ac-hE-18A-NH2 dramatically decreases plasma cholesterol in different dyslipidemic mouse models and WHHL rabbits. Preliminary results also show that the peptide possesses antiinflammatory properties. This occurs through a lowering of plasma lipid hydroperoxide levels concomitant with a significant increase in plasma paraoxonase activity. In the WHHL model, the LDL-R pathway is compromised, thus the peptide-mediated atherogenic lipoprotein clearance is likely via the cell surface heparan sulfate proteoglycan (HSPG)-mediated pathway, as described earlier by us in murine models. In a second rabbit model of atherosclerosis, New Zealand White (NZW) rabbits fed an atherogenic diet, a single intravenous administration (3mg/kg) of the peptide significantly decreased total plasma cholesterol levels for 15 days. En face analysis of the lesions after 50 days showed approximately 50% lesion coverage in the saline administered rabbits (control), while little to no lesion in the peptide-treated animals. We therefore hypothesize that both cholesterol-dependent and -independent properties of these novel peptides contribute to the beneficial effects of the peptides to inhibit atherogenesis. We propose two specific aims to further investigate the mechanism of action of these two types of peptides: Specific Aim 1: Effect of peptides on A) uptake of apoB-containing lipoproteins in hepatocytes isolated from different dyslipidemic mouse models and rabbit models and in HepG2 cells. B) Changes in apoA-I and apoE-containing particles and their anti- inflammatory properties. Specific Aim 2: Effect of peptides on A) plasma cholesterol levels, B) lesion inhibition in animal models of atherosclerosis, and C) modulation of HDL properties. Research towards the understanding of the antiatherogenic properties of these novel peptides would yield a better understanding of cholesterol homeostasis and could lead to novel therapeutic reagents that would be useful in the treatment of atherosclerosis and its sequelae. PUBLIC HEALTH RELEVANCE: An ideal treatment for atherosclerosis would involve rapid clearance of plasma cholesterol and inhibition of inflammatory pathways. Recent advances in apoA-I mimetic peptides indicate the possibility of improving HDL function. This proposal deals with ways of incorporating properties of lowering plasma apolipoprotein B- containing lipoproteins with properties of improving HDL function. This is hypothesized to preserve both the anti- inflammatory and cholesterol reducing functions in designed peptides in order to obtain a peptide that would be ideal for the treatment of atherosclerosis and related lipid related inflammatory disorders.