Mechanisms of cLDL-Induced Endothelial Injury

cLDL 引起的内皮损伤的机制

• 批准号: 8598066
• 负责人: Sudhir V Shah
• 金额: --
• 依托单位: CENTRAL ARKANSAS VETERANS HLTHCARE SYS
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-10-01 至 2015-09-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8598066
• 关键词: Accounting; Acute; Adhesions; Adult; Apolipoprotein E; Atherosclerosis; Attenuated; Biological; Blocking Antibodies; Blood; Blood Urea Nitrogen; CD36 gene; Cardiovascular Diseases; Cardiovascular system; Case-Control Studies; Caspase; Cause of Death; Cell Adhesion Molecules; Cell Death; Cells; Cessation of life; Chelating Agents; Cholesterol; Chronic; Chronic Kidney Failure; Common carotid artery; Consumption; Coronary; Coronary artery; DNA; DNA Fragmentation; Data; Deoxyribonuclease I; Deoxyribonucleases; Development; Diet; Endothelial Cells; Enzymes; Event; Exposure to; Fatty acid glycerol esters; Functional disorder; Future; General Population; Generations; Genetic; Health; Human; Hydrogen Peroxide; Immunohistochemistry; In Vitro; Injection of therapeutic agent; Injury; Iron; Iron Chelation; Knock-out; Knockout Mice; LOX gene; Lipoprotein (a); Low-Density Lipoproteins; Mediating; Mediator of activation protein; Methods; Modeling; Molecular Target; Mus; Operative Surgical Procedures; Oxidants; Oxygen; Pathway interactions; Patients; Plasma; Prevalence; Prevention; Process; Proteins; RNA Interference; Regulation; Risk; Risk Factors; Role; Sampling; Smooth Muscle Myocytes; Superoxides; Testing; Thick; Toxic effect; United States; Urea; Uremia; Vascular Endothelial Cell; Veterans; Wild Type Mouse; atherogenesis; cardiovascular risk factor; caspase-3; cell injury; cell type; cellular targeting; cytotoxicity; data modeling; disability; drinking water; endonuclease G; feeding; follow-up; improved; in vivo; inhibitor/antagonist; intima media; monocyte; mortality; mouse model; nuclease; prevent; research study; response; scavenger receptor; therapeutic target; treatment strategy

DESCRIPTION (provided by applicant): The prevalence of chronic kidney disease (CKD) is increasing worldwide. In the United States, over 20 million adults have CKD, and traditional cardiovascular risk factors do not account for this. Blood urea dissociates to form cyanate that may alter proteins including low-density lipoprotein (LDL) by a process known as carbamylation. Our recent studies demonstrate that cLDL has all of the biological effects relevant to atherosclerosis: (a) cLDL induces injury to human coronary artery endothelial cells; (b) it induces adhesion molecule expression and monocyte adhesion on human coronary artery endothelial cells; and (c) it causes proliferation of human coronary artery smooth muscle cells. In addition, we have demonstrated that elevated plasma cLDL concentration from either chronic kidney failure or chronic urea consumption results in the development of aortic atherosclerosis in mice. Our case-control study in uremic patients revealed a strong positive correlation between elevated cLDL and an increase in common carotid artery intima-media thickness (IMT), an accepted quantifiable marker of early atherosclerosis. One of the major events that occurs in response of cLDL exposure to endothelial cells is the induction of DNA fragmentation and cell death. The mechanisms by which cLDL induces endothelial cell injury, an early step in atherosclerosis, are not known. The central hypothesis of this proposal is that cLDL elevated by CKD induces endothelial cell injury by activating EndoG to promote atherosclerosis, and that inactivation of endothelial EndoG will blunt endothelial cell death and atherogenesis in uremic mice. Our preliminary studies show that endothelial cell death induced by cLDL depends on the expression of endonuclease G (EndoG), the nuclease associated with caspase-independent DNA fragmentation. Ex vivo experiments with primary endothelial cells isolated from wild-type (WT) and EndoG null knockout (KO) mice demonstrated that KO cells are partially protected against cLDL toxicity compared to WT cells. Our results showed increased number of floating endothelial cells after cLDL injection compared to nLDL in WT mice but not in KO mice. These data point to EndoG as an important mediator of cLDL toxicity to endothelial cells, and suggest that EndoG is a potential therapeutic target for cLDL cytotoxicity and, potentially, atherosclerosis. To study the cLDL-EndoG pathway, we plan: Aim 1. Determine molecular and cellular targets of cLDL causing activation of EndoG in vitro and in vivo. Aim 2. Evaluate the role of likely upstream regulators of EndoG in cLDL-induced endothelial cell death in vitro and in vivo. Aim 3. Test whether genetic inactivation of EndoG or inhibition of mechanisms upregulating EndoG attenuate uremia/cLDL-induced endothelial cell injury and atherosclerosis. Recent studies showed that among veterans, traditional cardiovascular risk factors CVD and CKD are highly prevalent, and CKD is associated with an increased risk of baseline CVD and follow-up mortality. Our study is aimed to determine whether regulation of the cLDL mediator EndoG or its upstream mechanisms may be beneficial for protection against acute endothelial injury and atherosclerosis induced by cLDL. Therefore, the results of this study may eventually save human lives, improve the health and well being of veterans, and decrease the number of disabilities among veterans and in the general population.

描述(由申请人提供)： 慢性肾脏疾病(CKD)的患病率在全球范围内呈上升趋势。在美国，超过2000万成年人患有慢性肾脏病，而传统的心血管危险因素没有考虑到这一点。血尿素解离形成氰酸盐，可能会通过氨甲酰化过程改变包括低密度脂蛋白(LDL)在内的蛋白质。我们最近的研究表明，cLDL具有与动脉粥样硬化相关的所有生物学效应：(A)cLDL诱导人冠状动脉内皮细胞损伤；(B)诱导人冠状动脉内皮细胞表达黏附分子和单核细胞黏附；(C)引起人冠状动脉平滑肌细胞增殖。此外，我们已经证明，慢性肾功能衰竭或慢性尿素消耗导致的血浆cLDL浓度升高会导致小鼠动脉粥样硬化的发生。我们在尿毒症患者中进行的病例对照研究显示，cLDL升高与颈总动脉内中膜厚度(IMT)增加呈显著正相关，IMT是公认的早期动脉粥样硬化的可量化标记物。CLDL暴露于内皮细胞后发生的主要事件之一是诱导DNA片段化和细胞死亡。CLDL诱导内皮细胞损伤的机制尚不清楚，这是动脉粥样硬化的早期步骤。这一假设的核心假设是CKD升高的cLDL通过激活endog促进动脉粥样硬化而导致内皮细胞损伤，而内皮endog的失活将阻碍尿毒症小鼠内皮细胞的死亡和动脉粥样硬化的形成。我们的初步研究表明，cLDL诱导的内皮细胞死亡依赖于核酸内切酶G的表达，该核酸酶与caspase非依赖的DNA片段有关。从野生型(WT)和endog空基因敲除(KO)小鼠分离的原代内皮细胞的体外实验表明，与WT细胞相比，KO细胞可以部分地对抗cLDL毒性。我们的结果显示，注射cLDL后，WT小鼠漂浮内皮细胞的数量比nLDL增加，而KO小鼠则没有。这些数据表明，endog是cLDL对内皮细胞毒性的重要介质，并提示endog是cLDL细胞毒性以及潜在的动脉粥样硬化的潜在治疗靶点。为了研究cLDL-endog通路，我们计划：目的1.确定cLDL在体外和体内激活endog的分子和细胞靶点。目的2.在体内外评价可能的endog上游调控因子在cLDL诱导内皮细胞死亡中的作用。目的3.检测endog基因失活或抑制endog上调机制是否能减轻尿毒症/低密度脂蛋白诱导的内皮细胞损伤和动脉粥样硬化。最近的研究表明，在退伍军人中，传统的心血管危险因素CVD和CKD非常普遍，CKD与基线CVD和随访死亡率的风险增加相关。我们的研究旨在确定调节cLDL介导物endog或其上游机制是否有助于对抗cLDL诱导的急性内皮损伤和动脉粥样硬化。因此，这项研究的结果最终可能会拯救人类的生命，改善退伍军人的健康和福祉，并减少退伍军人和普通人群中的残疾人数。