PREVENTION OF VASCULOPATHY AND NEPHROPATHY IN METABOLIC SYNDROME

描述(由申请人提供)：糖尿病和代谢综合征患者心血管系统加速的动脉粥样硬化和过早老化已经达到流行的程度。我们之前对内皮细胞在模拟糖尿病环境的微环境中的研究表明，细胞衰老的发展加速。根据观察到硝基酪氨酸修饰的蛋白在过早衰老的细胞中表达增强，以及过氧亚硝酸盐处理完整细胞导致提前衰老，我们用真正的过氧亚硝酸盐清除剂/抗氧化剂ebselen处理内皮细胞。这种治疗与预防和逆转早衰有关。这些发现促使我们研究代谢综合征-Zucker糖尿病大鼠模型细胞过早衰老的分子机制(S)，依布硒对内皮细胞过早衰老的影响，并观察这些动物血管病变的发展。我们假设氧化应激/过氧亚硝酸盐诱导的溶酶体功能障碍启动内皮细胞衰老和神经节苷脂的积累，这是从衰老到凋亡的分子开关--这些事件支撑着血管病变的进展。体外和体内研究采用图像分析和荧光活体显微镜，生化技术检测溶酶体和线粒体蛋白的泄漏以及神经节苷脂的积累，以及细胞周期标志物的定量分析，以探讨过早衰老和细胞凋亡的分子和细胞机制。用依布塞伦治疗Zucker糖尿病肥胖大鼠的体内研究将考察预防和逆转这种综合征的大血管和微血管病变(肾病)的可能性。这些研究可能有助于阐明内皮细胞早衰的机制，过氧亚硝酸盐在其中的作用，以及过氧亚硝酸盐清除在改善血管病变中的潜在治疗作用。

DESCRIPTION (provided by applicant): Accelerated atherosclerosis and premature aging of the cardiovascular system in patients with diabetes mellitus and metabolic syndrome have acquired epidemic proportions. Our previous studies of endothelial cells subjected to a microenvironment emulating the diabetic milieu revealed accelerated development of cell senescence. Based on the observations that the expression of nitrotyrosine-modified proteins was enhanced in the prematurely senescent cells and peroxynitrite treatment of intact cells led to premature senescence, we treated endothelial cells with a bona fide peroxynitrite scavenger/antioxidant ebselen. Such a treatment was associated with the prevention and reversal of premature senescence. These findings prompted us to investigate the molecular mechanism(s) of premature cell senescence, effects of ebselen on premature endothelial cell senescence in a model of metabolic syndrome - Zucker diabetic rats, and examine the development of vasculopathy in these animals. We hypothesize that oxidative stress/peroxynitrite-induced lysosomal dysfunction initiates endothelial cell senescence and accumulation of gangliosides, a molecular switch from senescence to apoptosis - events underpinning the progression of vasculopathy. In vitro and in vivo studies employing image analysis and fluorescence intravital microscopy, biochemical techniques to detect leakage of lysosomal and mitochondrial proteins as well as accumulation of gangliosides, and quantitative analysis of the markers of cell cycle are designed to investigate molecular and cellular mechanisms of premature senescence and apoptosis. In vivo studies of the Zucker diabetic fat rat treated with ebselen will be conducted to examine the possibility of preventing and reversing macro- and micro-vasculopathy (nephropathy) in this syndrome. The investigations may shed light on mechanisms of premature senescence of endothelial cells, role of peroxynitrite in initiating it, and potential therapeutic efficacy of peroxynitrite scavenging in amelioration of vasculopathy.