Impact of dyslipidemia on endothelial biomechanics

血脂异常对内皮生物力学的影响

• 批准号: 9041643
• 负责人: Irena Levitan
• 金额: $ 54.89万
• 依托单位: UNIVERSITY OF ILLINOIS AT CHICAGO
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-09-04 至 2018-09-23
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9041643
• 关键词: Accounting; Actins; Address; Antiatherogenic; Aorta; Apolipoprotein E; Atherosclerosis; Atomic Force Microscopy; Belief; Biological Assay; Biomechanics; Blood Vessels; Cardiovascular Diseases; Caveolins; Cell membrane; Cell physiology; Cessation of life; Cholesterol; Complex; Deposition; Development; Disease; Dyslipidemias; Endothelial Cells; Endothelium; Environment; Event; Exposure to; Functional disorder; Funding; Goals; Grant; Guanosine Triphosphate Phosphohydrolases; Harvest; Image; Impairment; In Vitro; Individual; Inflammatory; Link; Lipids; Low-Density Lipoproteins; Mass Spectrum Analysis; Measures; Mechanics; Mediating; Membrane; Microscopy; Modeling; Modification; Morbidity - disease rate; Mus; Myosin ATPase; Myosin Light Chains; Pathway interactions; Permeability; Phosphorylation; Plasma; Play; Property; Regulation; Resistance; Rho-associated kinase; Risk Factors; Role; Scheme; Signal Pathway; Signal Transduction; Staging; Testing; Tissues; Woman; athero susceptible; base; biophysical techniques; caveolin 1; cell injury; disorder prevention; endothelial dysfunction; gain of function; hemodynamics; in vivo; insight; loss of function; low density lipoprotein inhibitor; men; mutant; myosin phosphatase; novel; oxidized lipid; oxidized low density lipoprotein; response; rho; rho GTP-Binding Proteins; shear stress; two-photon; uptake

DESCRIPTION (provided by applicant): Biomechanical properties of endothelial cells (ECs) are crucially important in regulation of multiple EC functions, such as mechanotransduction and the integrity of the EC barrier. We have recently discovered that oxidized modifications of LDL (oxLDL) induce significant EC stiffening indicating that dyslipidemia plays a major role in the regulation of EC mechanics. Our long term goal is to elucidate the mechanisms responsible for dyslipidemia-induced changes in EC biomechanics and to determine the contribution of these mechanisms to endothelial dysfunction. During the first funding period of this grant, we have provided the first mechanistic insights into oxLDL-induced EC stiffening and demonstrated that it may facilitate the sensitivity of endothelial cells to flow. In the current proposal, we extend thee studies to address three new goals: In Aim 1, we will identify specific oxidized lipids that induce EC stiffening and address the hypothesis that EC stiffening is mediated by the insertion of oxidized lipids into the plasma membranes of endothelial cells and disruption of lipid packing of membrane domains. To achieve this goal, we will perform Mass Spectrometry analysis of oxidized lipids found in both oxLDL complex and in the vascular walls of aortas isolated from dyslipidemic ApoE-/- mice. EC stiffness will be measured using a combination of two biophysical techniques, Microaspiration and Atomic Force Microscopy and lipid packing will be assayed by two-photon microscopy. In Aim 2, we will elucidate the downstream signaling pathways that are responsible for oxLDL-induced EC stiffening focusing on the roles of caveolin and Rho-GTPases. Specifically, we will address a hypothesis that oxLDL/oxidized lipids-induced disruption of cholesterol-rich membrane domains activate a signaling pathway that includes phosphorylation of caveolin-1, activation of Rho-GTPase and its major downstream target, ROCK, with subsequent changes in actin/myosin organization. This hypothesis will be addressed using an array of gain-of-function and loss-of-function mutants of caveolin, Rho and Rac- GTPases and ROCK. In Aim 3, we will determine the impact dyslipidemia-induced EC stiffening on endothelial permeability under different hemodynamic environments in vitro and in vivo. More specifically, first we will test the hypothesis that oxLDL-induced EC stiffening impairs EC barrier and augments an increase in EC permeability under disturbed pro-atherogenic flow environment in vitro. Finally, we will determine whether an increase in EC stiffness correlates with an increase in endothelial permeability in vivo in ApoE-/- mice and determine whether disruption of the endothelial barrier in ApoE-/- mice can be rescued by caveolin-1 deficiency and/or ROCK inhibition.

描述（由申请人提供）：内皮细胞（ECs）的生物力学特性在多种EC功能的调节中至关重要，如机械转导和EC屏障的完整性。我们最近发现LDL的氧化修饰（oxLDL）诱导EC显著硬化，表明血脂异常在EC力学调节中起主要作用。我们的长期目标是阐明血脂异常引起EC生物力学变化的机制，并确定这些机制对内皮功能障碍的贡献。在该基金的第一个资助期内，我们首次提供了oxldl诱导EC硬化的机制见解，并证明它可能促进内皮细胞对血流的敏感性。在目前的提案中，我们扩展了三项研究，以解决三个新的目标：在目标1中，我们将确定诱导的特异性氧化脂质