Oxidants, Eicosanoids and Endothelium in Diabetes

糖尿病中的氧化剂、类二十烷酸和内皮细胞

• 批准号: 7441025
• 负责人: RICHARD J COHEN
• 金额: $ 46.38万
• 依托单位: BOSTON MEDICAL CENTER
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/7441025
• 关键词: 3-nitrotyrosine; AICA ribonucleotide; Abbreviations; Adenine; Adenovirus Vector; Adhesions; Affect; Agonist; Apolipoprotein E; Apoptosis; Atherosclerosis; Blood Vessels; Cell Adhesion Molecules; Cell physiology; Cells; Condition; Cyclic GMP; Diabetes Mellitus; Dominant-Negative Mutation; Eicosanoids; Eko; Endothelial Cells; Endothelium; Enzymes; Epoprostenol; Event; Exposure to; F2-Isoprostanes; Fatty Acids; Glucose; Human; Hyperglycemia; Hyperlipidemia; Intercellular adhesion molecule 1; Knockout Mice; Leukocytes; Low Density Lipoprotein Receptor; Measures; Mediating; Mitochondria; Modeling; Mus; NADP; NADPH Oxidase; Niacinamide; Nitrates; Nonesterified Fatty Acids; Numbers; Oxidants; Peroxonitrite; Play; Positioning Attribute; Principal Investigator; Production; Prostacyclin synthase; Prostaglandin H2; Protein Overexpression; Proteins; Reaction; Role; Source; Streptozocin; Stress; Superoxide Dismutase; Superoxides; TNF gene; Thromboxane A2 Receptor; Thromboxane Receptor; Transgenic Mice; Tyrosine; Umbilical vein; Vascular Cell Adhesion Molecule-1; adenylate kinase; atherogenesis; cytokine; day; diabetic; diphenyleneiodonium; human NOS2A protein; in vivo; inorganic phosphate; insight; intercellular cell adhesion molecule; mouse model; nitrate; nitration; prevent; programs

Our preliminary studies establish new insights into how elevated glucose increases oxidant stress and the mechanisms by which its effects on cell function are mediated. Exposure of cultured human endothelial cells to elevated glucose for 7-10 days increases the production of both NO and superoxide anion (Oa-). NO is inactivated by reacting with 02- to form the reaction product, peroxynitrite (OONO), and increased levels of its reaction product with tyrosine, nitrotyrosine, is found in the cells. Although the fimction of many proteins may be affected, we have found that prostacyclin synthase (PGIS) is inactivated by tyrosine nitration in endothelial cells grown in elevated glucose. This may not only explain why diabetes decreases levels of PGI2, but also why increases have been noted in the PGI2 precursor, PGH2, which activates thromboxane A2 receptors (TPr). Activation of TPr can increase VCAM-1 and ICAM-1 expression as well as apoptosis of human endothelial cells. Expression of adhesion molecules and apoptosis, two events important in atherogenesis, are also enhanced by O2-, and indeed, exposure to elevated glucose enhances adhesion molecule expression and apoptosis by mechanisms which depend on O2- and TPr. Indeed, we have found that blockade of TPr inhibits the dramatic enhancement by diabetes ofatherogenesis in the Apo E deficient mouse. Our overall hypothesis is that the effects of oxidant stress in the endothelium in atherogenesis are importantly mediated via TPr as a result of inactivation of PGIS. Furthermore, in the context of this program, we have found that AICAR, a stimulator of AMP kinase, prevents the oxidant stress in endothelial cells exposed to elevated glucose, and inhibits VCAM-1 expression induced by TNF_. Our aims are: 1) To determine the mechanism by which elevated glucose and fatty acids increases production of NO and 02- and causes tyrosine nitration and inactivation ofPGI synthase. The role of AMP kinase in regulating oxidant stress via PKC will be studied. 2) To determine the role of TPr stimulation by eicosanoid products due to endothelial cell oxidant stress and PGI synthase inactivation in causing the increased leukocyte adhesion and apoptosis caused by high glucose and fatty acids, and 3) to determine if oxidant stress, PGIS inactivation, and TPr contr_ute to the increased atherogenesis caused by diabetes in transgenie mouse models. Activation of AMP kinase as a strategy for reducing oxidant stress will be explored.

我们的初步研究为葡萄糖升高如何增加氧化应激和氧化应激提供了新的见解。 其对细胞功能的影响是通过其机制介导的。培养的人内皮细胞的暴露 升高葡萄糖7-10天后，NO和超氧阴离子（Oa-）的产生均增加。NO是 通过与O2-反应以形成反应产物过氧亚硝酸盐（OONO）而失活，并且增加的过氧亚硝酸盐的水平。 其与酪氨酸的反应产物硝基酪氨酸存在于细胞中。虽然许多蛋白质的功能 可能受到影响，我们已经发现前列环素合酶（PGIS）被酪氨酸硝化失活， 内皮细胞在高浓度葡萄糖中生长。这不仅可以解释为什么糖尿病会降低 PGI 2，但也为什么增加已注意到PGI 2前体，PGH 2，激活血栓烷A2 受体（TPr）。TPr的激活可增加VCAM-1和ICAM-1的表达以及细胞凋亡。 人内皮细胞粘附分子的表达和细胞凋亡， 动脉粥样硬化形成，也被O2-增强，事实上，暴露于升高的葡萄糖会增强粘附 分子表达和细胞凋亡的机制依赖O2-和TPr。我确已发现， 阻断TPr可抑制糖尿病对载脂蛋白E缺陷型糖尿病患者的造血功能的显著增强， 老鼠.我们的总体假设是氧化应激在动脉粥样硬化形成中的作用 作为PGIS失活的结果，重要地通过TPr介导。此外，在此背景下， 我们已经发现AICAR，一种AMP激酶的刺激剂，可以防止内皮细胞的氧化应激， 细胞暴露于高浓度葡萄糖，并抑制VCAM-1的表达由TNF_α诱导。我们的目标是：1） 确定升高的葡萄糖和脂肪酸增加NO和O2-的产生的机制， 导致酪氨酸硝化和PGI合成酶失活。AMP激酶在氧化调节中的作用 将研究通过PKC的应激。2)为了确定类花生酸产物对TPr刺激的作用， 内皮细胞氧化应激和PGI合酶失活导致白细胞粘附增加， 由高糖和脂肪酸引起的细胞凋亡，和3）确定氧化应激，PGIS失活， 而TPr在转基因小鼠模型中与糖尿病引起的动脉粥样硬化形成增加相反。激活 AMP激酶作为减少氧化应激的策略将被探索。