Apo E mimetics reduce cholesterol and improve HDL function

描述（由申请人提供）：动脉粥样硬化的理想治疗包括快速清除血浆胆固醇和抑制炎症途径。apoA-I模拟肽的最新进展表明，它有可能改善HDL的功能。本建议探讨结合降低血浆载脂蛋白B-含脂蛋白的特性与改善HDL功能的特性的方法。我们的假设是，这些肽不仅保留了改善HDL功能的特性，而且还增强了含载脂蛋白的脂蛋白的清除，从而降低了血浆胆固醇水平。因此，我们设计了新的多肽，该多肽具有apoE的阳离子推定受体结合域，该受体结合域与活性apoA-I模拟肽域共价连接。我们还设计了一种单域阳离子肽，我们将apoA-I模拟物的脂质过氧化氢清除特性纳入其中。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apoE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可显著降低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，该肽具有抗炎特性。这是通过降低血浆脂质过氧化氢水平同时显著增加血浆对氧磷酶活性而发生的。在WHHL模型中，LDL-R通路被破坏，因此肽介导的致动脉粥样硬化脂蛋白清除可能通过细胞表面硫酸肝素蛋白聚糖（HSPG）介导的途径，正如我们之前在小鼠模型中描述的那样。在第二种动脉粥样硬化兔模型中，新西兰白兔（NZW）饲喂致动脉粥样硬化饮食，单次静脉注射（3mg/kg）肽显著降低血浆总胆固醇水平，持续15天。50天后对病变的面部分析显示，生理盐水兔（对照组）的病变覆盖率约为50%，而肽治疗兔的病变几乎没有。因此，我们假设这些新肽的胆固醇依赖性和非依赖性都有助于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的：特定目的1：多肽对不同血脂异常小鼠模型和兔模型分离的肝细胞以及HepG2细胞中含载脂蛋白的摄取的影响。B)含apoA-I和apoe颗粒的变化及其抗炎特性。特异性目标2：肽对A)血浆胆固醇水平的影响，B)动脉粥样硬化动物模型中的病变抑制，以及C) HDL特性的调节。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稳态，并可能导致新的治疗试剂对动脉粥样硬化及其后遗症的治疗有用。公共卫生相关性：动脉粥样硬化的理想治疗包括快速清除血浆胆固醇和抑制炎症途径。apoA-I模拟肽的最新研究进展表明其有改善HDL功能的可能性。本建议探讨结合降低血浆载脂蛋白B-含脂蛋白的特性与改善HDL功能的特性的方法。假设这是为了保留所设计肽的抗炎和降胆固醇功能，以获得治疗动脉粥样硬化和相关脂质相关炎症性疾病的理想肽。

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.