MACROPHAGE CELL-SURFACE PROTEOLYSIS IN ATHEROGENESIS

动脉粥样硬化形成中的巨噬细胞表面蛋白水解

• 批准号: 6861526
• 负责人: Elaine W Raines
• 金额: $ 37.9万
• 依托单位: UNIVERSITY OF WASHINGTON
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-01-01 至 2005-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6861526
• 关键词: CD95 molecule; atherosclerosis; atherosclerotic plaque; cell surface receptors; enzyme activity; free radical oxygen; genetically modified animals; immunogenetics; inflammation; laboratory mouse; leukocyte activation /transformation; macrophage; metalloendopeptidases; oxidative stress; pathologic process; proteolysis; receptor expression; scavenger receptor

DESCRIPTION (provided by applicant): Numerous studies examining atherosclerotic lesions from human and animal models have established the central role of the macrophage in atherosclerosis. Despite these observations, it is still unclear how the multiple pro- and anti-inflammatory capabilities of the macrophage are balanced within lesions. One potentially important mechanism for them to regulate their function is by the rapid modulation of the repertoire of proteins expressed on their cell surface through proteolytic "shedding". In addition to dynamically altering the cell surface constituents, shedding also leads to the release of soluble ectodomains with distinct biological properties. This proposal will focus on the ADAM family of proteases that have gained recognition as primary effectors of ectodomain shedding. Early lesions of atherosclerosis are characterized by lipid-filled macrophages. Scavenger receptors are responsible for this massive accumulation of cholesterol, and their significance for atherogenesis is highlighted by multiple gene knockout studies. Fas ligand (FasL) is a key regulator of macrophage apoptosis and activation. Both scavenger receptors and FasL can be proteolytically cleaved from the cell surface, and their proteolytic shedding could modulate lesion progression. However, the enzymes responsible for their shedding have not been fully characterized. In Aim 1, we will determine the proteases involved in the shedding of scavenger receptors and FasL, and the functional significance of shedding on atherogenesis will be examined by expressing uncleavable mutants of these substrates in Aim 3. Macrophage activation is observed at all stages of lesion development, and induces the shedding of a multitude of inflammatory proteins. ADAM17 has been shown to be responsible for the shedding of a large number of inflammatory mediators, but the mechanisms that underlie the activation of ADAM17 are poorly understood. In Aim 2, the role played by oxidants in regulating the activity of ADAM17 will be investigated. Finally in Aim 3, we will test the role of ADAM17 in lesion initiation, progression and plaque rupture by genetically modulating its expression in macrophages.

描述（由申请人提供）：许多研究检查了来自人类和动物模型的动脉粥样硬化病变，已经确定了巨噬细胞在动脉粥样硬化中的中心作用。尽管有这些观察结果，但仍不清楚巨噬细胞的多种促炎和抗炎能力如何在病变内平衡。它们调节其功能的一个潜在的重要机制是通过蛋白水解“脱落”快速调节在其细胞表面上表达的蛋白质库。除了动态改变细胞表面成分外，脱落还导致具有不同生物学特性的可溶性胞外域的释放。这项建议将集中在ADAM家族的蛋白酶，已获得认可的主要效应细胞外结构域脱落。动脉粥样硬化的早期病变以充满脂质的巨噬细胞为特征。清道夫受体是胆固醇大量积累的原因，多基因敲除研究强调了清道夫受体在动脉粥样硬化形成中的重要性。Fas配体（FasL）是巨噬细胞凋亡和活化的关键调节因子。清道夫受体和FasL都可以从细胞表面蛋白水解切割，并且它们的蛋白水解脱落可以调节病变进展。然而，负责其脱落的酶尚未完全表征。在目标1中，我们将确定参与清道夫受体和FasL脱落的蛋白酶，并通过在目标3中表达这些底物的不可切割突变体来检查脱落对动脉粥样硬化形成的功能意义。在病变发展的所有阶段都观察到巨噬细胞活化，并诱导大量炎性蛋白的脱落。已显示ADAM 17负责大量炎症介质的脱落，但对ADAM 17激活的机制知之甚少。在目标2中，将研究氧化剂在调节ADAM 17活性中所起的作用。最后，在目标3中，我们将通过遗传调节巨噬细胞中的ADAM 17表达来测试ADAM 17在病变起始、进展和斑块破裂中的作用。