Apolipoproteins and Amyloid Formation in Atheroma

我们建议使用我们实验室开发的敏感和可重复性的模型来研究知之甚少的、与疾病相关的淀粉样蛋白形成过程。淀粉样沉积是阿尔茨海默氏症和帕金森氏症等多种神经退行性和代谢性疾病的特征，在动脉粥样硬化斑块或动脉粥样硬化中也很常见。它们是由纤维蛋白以及几种非纤维蛋白和蛋白多糖组成的缠绕网络。动脉粥样硬化斑块通常由纤维蛋白、脂类和泡沫细胞组成，通过受体介导的氧化低密度脂蛋白摄取来自巨噬细胞。我们的模型系统是基于载脂蛋白(Apo)C-II形成的淀粉样纤维，它聚集在动脉粥样硬化斑块中，在那里它与血清淀粉样蛋白P组分共同定位，血清淀粉样蛋白P组分是淀粉样纤维的标志。载脂蛋白C-II是血浆脂蛋白的一种成分，也是脂蛋白脂酶的重要激活剂，在三酰甘油向组织的运输和分布中起着重要的作用。我们已经证明apoC-II(79个氨基酸)在无脂条件下很容易形成淀粉样纤维，采用交叉β片状结构，与淀粉样染色硫代黄素T和刚果红反应。载脂蛋白C-II类淀粉样纤维的形成和性质以及氧化脂蛋白的类淀粉样属性是本提案的主题。我们将描述脂质和氧化对载脂蛋白C-II淀粉样纤维的形成速度和性质的影响。我们还将研究氧化对脂蛋白类淀粉样属性的影响，以及它们与血清淀粉样蛋白P组分和细胞表面受体的相互作用。

We propose to study the poorly understood, disease-associated process of amyloid formation, using a sensitive and reproducible model developed in our laboratory. Amyloid deposits are a feature of several neurodegenerative and metabolic disorders such as Alzheimer's and Parkinson's disease and are also common in atherosclerotic plaque or atheroma. They are composed of tangled networks of fibrillar proteins together with several non-fibrillar proteins and proteoglycans. Atherosclerotic plaques typically consist of fibrous proteins, lipids and foam cells derived from macrophages via receptor-mediated uptake of oxidized low density lipoproteins. Our model system is based on the formation of amyloid fibrils from apolipoprotein (apo) C-II which accumulates in atherosclerotic plaques where it co-localizes with serum amyloid P component, a marker of amyloid fibrils. ApoC-II is a component of plasma lipoproteins and an important activator of the enzyme lipoprotein lipase, which functions in the transport and distribution of triacylglycerols to tissues. We have shown that apoC-II (79 amino acids) readily forms amyloid fibrils under lipid-free conditions, adopting a cross-beta sheet structure that reacts with the amyloid stains thioflavin T and Congo Red. The formation and properties of apoC-II amyloid fibrils and the amyloid-like properties of oxidized lipoproteins are the subject of the present proposal. We will characterize the effects of lipids and oxidation on the rate of formation and the properties of apoC-II amyloid fibrils. We will also study the effects of oxidation on the amyloid-like properties of lipoproteins and their interactions with serum amyloid P component and cell surface receptors.