apoE, arterial biomechanics, and cardiovascular disease

apoE、动脉生物力学和心血管疾病

• 批准号: 8771694
• 负责人: Richard Assoian
• 金额: $ 45.79万
• 依托单位: UNIVERSITY OF PENNSYLVANIA
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-09-01 至 2018-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8771694
• 关键词: Accounting; Address; Adhesions; Adult; Affect; Apolipoprotein E; Arterial Fatty Streak; Arteries; Atherosclerosis; Attenuated; Biology; Biomechanics; Cardiovascular Diseases; Cells; Cholesterol; Collaborations; Collagen; Complement; Cre-LoxP; Data; Development; Disease; Elasticity; Extracellular Matrix; Extracellular Matrix Proteins; Fibrillar Collagen; Fibronectins; Gene Expression; Genes; Goals; Guanosine Triphosphate; High Density Lipoproteins; In Vitro; Infiltration; Integrins; Knockout Mice; Lesion; Link; Lipid Binding; Lipoproteins; Mechanics; Microfabrication; Mus; Non-Fibrillar Collagens; Pathway interactions; Plasma; Production; Property; Protein-Lysine 6-Oxidase; Publications; Recording of previous events; Reporting; Rho-associated kinase; Risk Factors; Role; Signal Transduction; Smooth Muscle Myocytes; System; Technology; Testing; Tissue Model; Tissues; Work; adhesion receptor; arterial stiffness; cell motility; feeding; genome-wide; in vivo; inhibitor/antagonist; interest; macrophage; monocyte; mouse model; novel; public health relevance; research study; response; rho

DESCRIPTION (provided by applicant): Arterial stiffening is a risk factor for cardiovascular disease, but how arteries stay supple and how arterial stiffness contributes to disease are unknown. Our preliminary studies show that arterial elasticity is maintained by Apo lipoprotein E (apoE) and apoE-containing HDL through a suppressive effect on the expression of extracellular matrix genes. ApoE interrupts a mechanically driven feed-forward loop that increases the expression of collagen-I, fibronectin, and lysyl oxidase in response to substratum stiffening. These effects are independent of the apoE lipid-binding domain. Arterial stiffness is increased in apoE-null mice, this stiffening can be reduced by administration of the lysyl oxidase inhibitor, BAPN, and BAPN treatment attenuates atherosclerosis despite highly elevated cholesterol. Macrophage abundance in lesions is reduced by BAPN in vivo, and monocyte/macrophage adhesion is reduced by substratum softening in vitro. Mechanistically, we show that apoE and apoE-containing HDL inhibit Rho-GTP activity and reduce intracellular force in VSMCs. These changes in VSMC mechanics then affect ECM gene expression. Finally, we show that in addition to regulating (fibrillar) collagen-I, apoE and apoE-HDL inhibit the expression of collagen-VIII, a non-fibrillar collagen that has profound effects on VSMC function and atherosclerosis, yet is largely unexplored in terms of its mechanical properties and mechanistic effects. Overall, our data describe a completely new role for apoE and apoE-HDL that is independent of plasma cholesterol levels, intimately connected to cell and tissue mechanobiology, and causally linked to protection from atherosclerosis. We now propose three specific aims to characterize the relationships between apoE, intracellular force, matrix remodeling, and protection from atherosclerosis. In Aim 1, we will use a new micro fabrication platform of VSMC micro-tissues to study the effect of collagen-VIII on Rho-activity, contractility, ECM gene expression, and tissues stiffness in 3D. We will also use this system to determine how collagen-VIII controls the mechanical response to apoE. These in vitro studies will be complemented with an ex vivo analysis of arterial stiffness in apoE+/+ and apoE-/- arteries isolated from WT and collagen-VIII deficient mice. In Aim 2, we examine the mechanism by which stiffness controls atherosclerotic lesion development, with the particular goal of identifyin mechano-sensitive adhesion receptors that account for stiffness-dependent attachment of monocytes and macrophages to sub endothelial ECM protein. As in Aim 1, complementary in vivo experiments with existing mouse models will test the effect of arterial stiffness on monocyte abundance in vivo. Aim 3 will link the results in the first two aims by developing a new mouse model that can delete RhoA from VSMCs and establish the effect of reduced intracellular force on ECM gene expression, arterial stiffness, and atherosclerosis in vivo. This work brings together a team of three PI's (Assoian, Chen and Bendeck) with complementary expertise and an established track record of co- publication who, jointly, will establish how this novel regulatin of the ECM and VSMC mechanics by apoE provides cholesterol-independent protection against cardiovascular disease.

描述(申请人提供)：动脉硬化是心血管疾病的危险因素，但动脉如何保持柔软以及动脉僵硬如何导致疾病尚不清楚。我们的初步研究表明，载脂蛋白E(ApoE)和含apoE的高密度脂蛋白通过抑制细胞外基质基因的表达来维持动脉弹性。APOE阻断了机械驱动的前馈环路，该环路增加了I型胶原、纤维连接蛋白和赖氨酰氧化酶的表达，以响应底物僵硬。这些作用不依赖于载脂蛋白E的脂结合结构域。在apoE基因缺失的小鼠中，动脉僵硬增加，这种僵硬可以通过给予赖氨酰氧化酶抑制剂BAPN来减少，BAPN治疗可以减轻动脉粥样硬化，尽管胆固醇水平很高。在体内，BAPN可降低病变组织中巨噬细胞的丰度，在体外可通过软化基质减少单核/巨噬细胞的黏附。从机制上讲，我们发现载脂蛋白E和含载脂蛋白E的高密度脂蛋白抑制血管平滑肌细胞的Rho-GTP活性并降低细胞内力。VSMC机制的这些变化继而影响ECM基因的表达。最后，我们发现除了调节(纤维性)I型胶原，apoE和apoE-高密度脂蛋白还抑制VIII型胶原的表达，VIII型胶原是一种对VSMC功能和动脉粥样硬化有深远影响的非纤维性胶原，但其机械性能和机制作用在很大程度上尚不清楚。总体而言，我们的数据描述了载脂蛋白E和载脂蛋白E-高密度脂蛋白的全新作用，它独立于血浆胆固醇水平，与细胞和组织机械生物学密切相关，并与防止动脉粥样硬化有关。我们现在提出三个具体目标来描述载脂蛋白E、细胞内力、基质重塑和动脉粥样硬化保护之间的关系。在目标1中，我们将使用一个新的VSMC微组织微制造平台来研究VIII型胶原对血管活性，收缩， ECM基因表达和组织硬度的三维变化。我们还将使用这个系统来确定VIII型胶原如何控制对载脂蛋白E的机械反应。这些体外研究将与从WT和VIII型胶原缺陷小鼠分离的apoE+/+和apoE-/-动脉的动脉硬度的体外分析相补充。在目标2中，我们研究了僵硬控制动脉粥样硬化病变发展的机制，特别的目标是识别机械敏感的黏附受体，该受体解释了单核细胞和巨噬细胞与内皮下ECM蛋白的僵硬依赖的黏附。与目标1一样，用现有的小鼠模型进行的体内补充实验将测试动脉僵硬对体内单核细胞丰度的影响。目的3将通过建立一种新的小鼠模型将前两个目的的结果联系起来，该模型可以从VSMCs中删除RhoA，并在体内建立细胞内力降低对ECM基因表达、动脉僵硬和动脉粥样硬化的影响。这项工作汇集了一个由三位PI(Assoian、Chen和Bendeck)组成的团队，他们拥有互补的专业知识和既定的联合发表记录，他们将共同建立这一由apoE调节ECM和VSMC机制的新颖产品如何提供对心血管疾病的胆固醇非依赖性保护。