ROLE OF LP(A) IN THROMBOSIS AND ATHEROSCLEROSIS

LP(A) 在血栓形成和动脉粥样硬化中的作用

• 批准号: 5213985
• 负责人: RICHARD M LAWN
• 金额: --
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/5213985
• 关键词: DNA footprinting; apolipoproteins; atherosclerosis; blood vessels; gel mobility shift assay; gene expression; genetic promoter element; genetic regulatory element; genetic transcription; genetically modified animals; hemodynamics; human genetic material tag; laboratory mouse; molecular cloning; nucleic acid hybridization; nucleic acid sequence; plasminogen; polymerase chain reaction; site directed mutagenesis; thrombosis

Elevated plasma concentration of Lp(a) is one of the major inherited risk factors for atherosclerosis, and may account for roughly one-fourth of the heart attacks suffered by men under 60. Lp(a) resembles the cholesterol- rich low density lipoprotein (LDL), but is distinguished by the presence of an additional protein known as apolipoprotein(a), [apo(a)]. Apo(a) closely resembles plasminogen, providing a possible link between thrombosis and atherosclerosis. The plasma levels of apo(a) vary one thousand-fold in the population, yet for a given individual change little during lifetime. Apo(a) level is genetically determined with relatively little environmental influence. Since the level of apo(a) is linked to atherosclerosis, understanding of the regulation of gene expression and the molecular determinants for the variation between individuals is clearly important. We propose to clone human apo(a) genomic DNA, characterize its promoter region and study the transcriptional regulation of its expression. The 5' flanking region of the highly similar apo(a) and plasminogen genes will be compared. We will examine the apo(a) gene sequence variation between representative individuals with varied plasma apo(a) levels and attempt to establish a correlation between these parameters. We propose that variations in regulatory elements in the promoter region are responsible for the differences in apo(a) expression levels. This will be tested by transient expression studies using reporter gene approaches, by in vitro transcription and by site directed mutagenesis. The in vivo effect of sequence variations will be tested by hybridization and PCR analysis of family members. In the second part of this proposal, we will produce transgenic animals expressing human apo(a), to directly test its proposed role in the development of atherosclerosis and thrombosis. Arterial injury animal models will also be employed to study the ways in which elevated apo(a) may lead to accelerated restenosis, as implied by human epidemiologic studies.

LP（a）的血浆浓度升高是主要的遗传风险之一 动脉粥样硬化的因素，可能占大约四分之一的 60岁以下男性遭受的心脏病发作。LP（a）类似于胆固醇 - 丰富的低密度脂蛋白（LDL），但通过存在 一种称为载脂蛋白（a），[apo（a）]的额外蛋白质。 apo（a）紧密 类似于纤溶酶原，提供了血栓形成与 动脉粥样硬化。 Apo的血浆水平（a）在 人口，但对于给定的个人而言，一生中的变化很少。 Apo（a）水平是遗传确定的，用相对较少的环境确定 影响。 由于Apo（a）的水平与动脉粥样硬化有关 了解基因表达和分子的调节 个体之间变化的决定因素显然很重要。 我们提议克隆人apo（a）基因组DNA，以其启动子来表征 区域并研究其表达的转录调控。 5' 高度相似的Apo（A）和纤溶酶原基因的侧翼区域将是 比较的。 我们将检查APO（a）基因序列之间的变化 具有不同等离子体APO（a）水平的代表性个体，并尝试 在这些参数之间建立相关性。 我们提出了这一点 启动子区域调节元素的变化是负责 对于apo（a）表达水平的差异。 这将通过 使用报告基因方法的瞬时表达研究，通过体外 转录和通过位点定向诱变。 体内效应 序列变化将通过杂交和PCR分析测试 家庭成员。 在本提案的第二部分中，我们将生产 表达人apo（a）的转基因动物直接测试其提议 在动脉粥样硬化和血栓形成的发展中的作用。 动脉损伤 动物模型也将被用来研究升高的方式 如人所暗示的那样，Apo（a）可能导致加速再狭窄 流行病学研究。