Mechanism of Vascular Remodeling in Hyperhomocysteinemia

高同型半胱氨酸血症血管重塑机制

• 批准号: 6899590
• 负责人: Suresh C. Tyagi
• 金额: $ 3.69万
• 依托单位: UNIVERSITY OF LOUISVILLE
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-06-01 至 2006-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6899590
• 关键词: affinity chromatography; antihyperlipoproteinemic agent; atherosclerotic plaque; cardiovascular injury; clofibrate; elastin; homocystinuria; laboratory mouse; metalloendopeptidases; nitric oxide; peroxisome proliferator activated receptor; receptor binding; receptor expression; tyrosine; vasomotion; western blottings

DESCRIPTION (provided by the applicant): The long-term objective of this project is to further the understanding of contribution of homocysteine in vascular disease. Previous studies have indicated a decrease in the bioavailability of endothelial nitric oxide and an increase in the concentration of nitrotyrosine in the aortic wall associated with hyperhomocysteinemia. The plasma levels of homocysteine have shown to be inversely related to peroxisome proliferator activated receptor (PPAR), a nuclear receptor, which ameliorates vascular dysfunction. The central hypothesis of this proposal is that increased levels of homocysteine suppress the activity of PPAR by increasing the generation of nitrotyrosine and metalloproteinase activity, and decreasing the endothelial nitric oxide concentration. The central hypothesis will be addressed by the following four specific aims: 1) To determine whether the homocysteine binds to PPAR, the competitive binding of homocysteine and agonist (fibrate) to PPAR will be measured using homocysteine-cellulose affinity chromatography and aortic nuclear extracts. Bound PPAR will be eluted with fibrate and characterized by antibody to PPAR. 2) To determine whether the increase in PPAR expression decreases nitrotyrosine levels and increases endothelial nitric oxide concentration in a murine model of hyperhomocysteinemia, the concentrations of PPAR and nitrotyrosine in the aortas of hyperhomocysteinemic mice treated with and without fibrate will be measured by Western blot analysis. The levels of nitric oxide will be measured by estimating the total nitrate/nitrite concentration. 3) To determine whether the increase in PPAR decreases the levels of metalloproteinase and elastinolysis, the matrix metalloproteinase activity will be measured using specific substrate gel zymography, and the elastinolysis by identifying elastin fragments using anti-elastin antibody. 4) To determine whether an increase in PPAR expression reverses the homocysteine-mediated vascular dysfunction, the aortic contractile function will be measured. The proposed studies will elucidate the molecular, cellular and extracellular mechanism by which homocysteine promotes arterial lesions and should provide new insights to therapeutic ramifications for vessel wall disease.

描述（由申请人提供）：该项目的长期目标是进一步了解同型半胱氨酸在血管疾病中的作用。先前的研究表明，内皮一氧化氮的生物利用度降低以及主动脉壁中硝基酪氨酸浓度的增加与高同型半胱氨酸血症相关。血浆同型半胱氨酸水平与过氧化物酶体增殖物激活受体 (PPAR) 呈负相关，PPAR 是一种核受体，可改善血管功能障碍。该提议的中心假设是，同型半胱氨酸水平的增加通过增加硝基酪氨酸的产生和金属蛋白酶活性以及降低内皮一氧化氮浓度来抑制 PPAR 的活性。中心假设将通过以下四个具体目标来解决：1）为了确定同型半胱氨酸是否与 PPAR 结合，将使用同型半胱氨酸-纤维素亲和层析和主动脉核提取物来测量同型半胱氨酸和激动剂（贝特）与 PPAR 的竞争性结合。结合的 PPAR 将用贝特洗脱，并通过 PPAR 抗体进行表征。 2) 为了确定高同型半胱氨酸血症小鼠模型中 PPAR 表达的增加是否会降低硝基酪氨酸水平并增加内皮一氧化氮浓度，将通过蛋白质印迹分析测量用和不用贝特治疗的高同型半胱氨酸血症小鼠主动脉中 PPAR 和硝基酪氨酸的浓度。 。一氧化氮的水平将通过估计总硝酸盐/亚硝酸盐浓度来测量。 3)为了确定PPAR的增加是否降低金属蛋白酶和弹性蛋白溶解的水平，将使用特定底物凝胶酶谱法测量基质金属蛋白酶活性，并通过使用抗弹性蛋白抗体鉴定弹性蛋白片段来测量弹性蛋白溶解。 4)为了确定PPAR表达的增加是否逆转同型半胱氨酸介导的血管功能障碍，将测量主动脉收缩功能。拟议的研究将阐明同型半胱氨酸促进动脉病变的分子、细胞和细胞外机制，并为血管壁疾病的治疗后果提供新的见解。