Reactive nitrogen species and accelerated atherosclerosis

活性氮和加速动脉粥样硬化

基本信息

批准号：
7279125
负责人：
MING-HUI ZOU
金额：
$ 40.98万
依托单位：
UNIVERSITY OF OKLAHOMA HLTH SCIENCES CTR
依托单位国家：
美国
项目类别：
财政年份：
2004
资助国家：
美国
起止时间：
2004-09-30 至 2008-08-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7279125
关键词：
1,2-diacylglycerol 1-Phosphatidylinositol 3-Kinase 3-nitrotyrosine 4-ethoxymethylene-2-phenyl-2-oxazoline-5-one Abbreviations Affect Agonist Antioxidants Apolipoprotein E Apoptosis Arterial Fatty Streak Atherosclerosis Attenuated Biological Blood Vessels Bos taurus Cardiovascular Diseases Cattle Cell Adhesion Molecules Cell physiology Ceramides Condition Cyclic GMP Diabetes Mellitus Diglycerides Down-Regulation Endothelial Cells Epoprostenol Equilibrium GLUT4 gene Generations Glucose Glucose Transporter Human Hyperglycemia Insulin Knockout Mice Link Lipids Low Density Lipoprotein Receptor Mediating Molecular Mus NG-Nitroarginine Methyl Ester National Research Service Awards Nitrates Nitric Oxide Nonesterified Fatty Acids Numbers Oxidants Oxidative Stress Peroxonitrite Phosphatidylinositols Platelet aggregation Polyethylene Glycols Production Prostacyclin synthase Prostaglandin H2 Prostaglandin H2 Receptor Prostaglandin-Endoperoxide Synthase Prostaglandins Prostaglandins I Protein Kinase Protein Kinase C Protein Overexpression Proteins Proto-Oncogene Proteins c-akt Reaction Reactive Nitrogen Species Reactive Oxygen Species Receptors, Thromboxane A2, Prostaglandin H2 Resistance Role Signaling Molecule Somatomedins Source Streptozocin Stress Superoxide Dismutase Superoxides Thromboxane A2 Thromboxane A2 Receptor Thromboxane Receptor Thrombus Transgenic Organisms Tyrosine Vitamin E antioxidant therapy arginine methyl ester atherogenesis clinically relevant cyclooxygenase 1 cyclooxygenase 2 day diabetic human NOS3 protein insight low density lipoprotein inhibitor nitrate nitration polyethylene glycol-superoxide dismutase prevent progesterone 11-hemisuccinate-(2-iodohistamine)

项目摘要

DESCRIPTION (provided by applicant): There is evidence that reactive nitrogen species (RNS) derived from nitric oxide (NO) of endothelial nitric oxide synthase (eNOS), such as peroxynitrite (ONOO-), are important in cardiovascular diseases including diabetes. These oxidants would not be sensitive to "classical" lipid-soluble antioxidants such as vitamin E, which might explain why antioxidant therapy is ineffective in delivering sustained improvement. However, the mechanisms by which diabetes increases RNS, and those by which RNS modifies vascular functions are poorly understood. Our preliminary studies have established new insights into how hyperglycemia and free fatty acids (FFA) increase RNS and the mechanisms by which its effects on cell function are mediated. Exposure of cultured human aortic endothelial cells (HAEC) to clinically relevant concentrations of glucose (20 mM) and FFA (up to 0.5 mM) for 3 days additively increases the production of both NO and O2-, and, consequently, decreases the bioactivity of NO, as indicated by decreased levels of cyclic GMP. Further evidence that NO is inactivated by reacting with 02- to form the reaction products, ONOO-, is found in the increased levels of its reaction product with tyrosine, 3-nitrotyrosine (3-NT). While the function of many proteins may be affected, we have found that prostacyclin synthase (PGIS) is particularly susceptible to tyrosine nitration; the levels of nitrated PGIS increases and its activity decreases in HAEC grown in hyperglycemia/FFA. This may not only explain why diabetes decreases levels of PGI2, but also why an increase has been noted in its precursor PGH2 which activates upon thromboxane A2 receptor (termed TP receptor, TPr). Our preliminary studies have also shown that activation of TPr can modulate both adhesion molecule expression and apoptosis in HAEC. In addition, either TPr antagonist or inhibition of cyclooxygenase (COX) significantly attenuates both the expression of these adhesion molecules and apoptosis, suggesting activation of TPr by PGH2 occurs in HAEC exposed to hyperglycemia/FFA. Thus, our central hypothesis is that diabetes via hyperglycemia/hyperlipdemia increases the generation of 02- and then ONOO', resulting in eNOS uncoupling, PGIS nitration, and TPr stimulation. This contributes to the initiation and progression of vascular complications in diabetes mellitus because of the down-regulation of protective actions of NO and PGI2 and because the non-metabolized PGH2 tips the balance towards platelet aggregation, atheroma accumulation, and thrombus formation. Thus, the aims of the proposed studies are: (1) To elucidate the mechanism by which hyperglycemia and FFA increases the production of NO and O2-, as well as its reaction product ONOO-, and nitration and inactivation of PGIS in cultured HAEC; (2) To determine the role of TPr stimulation in enhancing endothelial cell adhesion molecules expression and apoptosis under conditions of increased oxidant stress caused by hyperglycemia and FFA; (3) To determine if oxidant stress and PGIS inactivation contribute to the diabetes-enhanced atherogenesis in transgenic and knockout mice.

描述（由申请人提供）：有证据表明，来自内皮一氧化氮合酶（ENOS）（例如过氧亚硝酸盐（ONOO-））的反应性氮种（RN）在心血管疾病中很重要。这些氧化剂不会对“经典”脂质溶质抗氧化剂（例如维生素E）敏感，这可能解释了为什么抗氧化剂治疗在提供持续改善方面无效。但是，糖尿病增加RN的机制，RNS修饰血管功能的机制知之甚少。我们的初步研究已经建立了有关高血糖和游离脂肪酸（FFA）如何增加RN的新见解以及其对细胞功能的影响的机制。培养的人主动脉内皮细胞（HAEC）暴露于临床相关的葡萄糖（20 mM）和FFA（最高0.5 mm）3天，加上NO和O2-的产生，从而降低了NO和O2-的产生，从而降低了NO的生物活性性，如环状GMP的降低所示。进一步的证据表明，通过与02-形成反应产物的反应在其与酪氨酸，3-硝基酪氨酸（3-nt）的反应产物水平上发现反应产物，从而灭活了NO。尽管许多蛋白质的功能可能受到影响，但我们发现前列环素合酶（PGIS）特别容易受到酪氨酸硝化的影响。高血糖/FFA中生长的HAEC的硝化PGI水平增加，其活性降低。这不仅可以解释为什么糖尿病会降低PGI2的水平，而且还为什么在其前体PGH2中注意到了糖尿病的增加，该前体PGH2在血栓烷A2受体（称为TP受体，TPR）上激活。我们的初步研究还表明，TPR的激活可以调节HAEC中的粘附分子表达和凋亡。此外，TPR拮抗剂或对环氧合酶（COX）的抑制显着减弱了这些粘附分子的表达和凋亡，表明PGH2激活TPR在暴露于高血糖/FFA的HAEC中。因此，我们的中心假设是通过高血糖/高脂血症通过糖尿病增加了02-，然后是Onoo'的产生，从而导致eNOS解偶联，PGIS硝化和TPR刺激。这有助于糖尿病中血管并发症的起始和进展，因为NO和PGI2的保护作用下调，并且由于非代谢的PGH2在血小板聚集，动脉粥样硬化的积累和血栓形成方面的平衡提示。因此，拟议的研究的目的是：（1）阐明高血糖和FFA增加NO和O2-的产生的机制，以及其反应产物Onoo-onoo-以及PGI在培养的HAEC中的硝化和硝化和失活；（2）确定TPR刺激在增强内皮细胞粘附分子表达和凋亡中的作用，这是高血糖和FFA引起的氧化应激增加的；（3）确定氧化应激和PGIS失活是否有助于转基因和基因敲除小鼠的糖尿病增强动脉粥样硬化。