POLY(ADP) RIBOSE SYNTHETASE AND AUTOIMMUNE DIABETES

描述(改编自申请人的摘要)：细胞和分子 自由基相关的胰岛破坏机制有 不完全理解。这种胰岛细胞死亡的药物调控 可能为糖尿病的实验性治疗提供新的途径。近期 对分离的胰岛细胞和其他细胞类型的研究表明 过氧亚硝酸盐和过氧化氢，在 免疫细胞介导的胰岛细胞攻击，触发细胞内级联反应 最终导致细胞能量衰竭。由以下因素引发的DNA链断裂 过氧化氢和过氧亚硝酸盐由特定的结构域识别 核酶多(ADP-核糖)合成酶(PARS)。这将导致 激活PARS，启动耗能的低效修复 循环，结果是二核苷酸池的耗尽，减缓了 糖酵解和线粒体呼吸，减少ATP合成。因此，Pars 作为细胞能量崩溃的终端媒介，导致细胞 坏死。初步数据表明，PARS的药理抑制作用 5-碘-6-氨基-1，2苯并吡喃酮(INH_2BP)--一种新型、有效的PARS抑制剂 减少高血糖的发展和胰岛细胞的腐烂 链脲佐菌素诱导的糖尿病模型。此外，来自该小组的数据，以及 同样来自另外两组研究人员的研究表明，Pars有缺陷 (基因敲除)小鼠对链脲佐菌素诱导的糖尿病具有抵抗力。因为 链脲佐菌素模型不能完全预测人类的情况， 当前议定书的第一个目标是调查分析程序的作用 自发性自身免疫性糖尿病病理生理学中的激活：PARS 将缺陷小鼠与NOD小鼠回交，并发育成 糖尿病将在这个模型中进行研究。胰腺胰岛素的病程 衰竭、胰岛炎症的病程和高血糖的发展 被监视。他们还将测试PARS抑制剂INH2 BP对 NOD模型糖尿病的发生发展过程。的第二个目标 建议的研究是在野生型和野生型胰岛中进行体外研究 PARS缺陷小鼠，以确定细胞死亡的模式(坏死和 过氧亚硝酸盐诱导的细胞凋亡)，并确定PARs在细胞凋亡中的作用 进程。目前的提议将提供(1)新的机械信息 自身免疫性糖尿病的机制，以及(2)将产生的数据将 帮助公司做出临床前发展的战略决策 一种新的，有效的，口服活性的PARS抑制剂。

DESCRIPTION (adapted from the applicant's abstract): The cellular and molecular mechanisms of free radical-related pancreatic islet destruction are incompletely understood. Pharmacological modulation of this islet cell death may provide novel avenues for the experimental therapy of diabetes. Recent studies in isolated islet cells, and other cell types demonstrate that peroxynitrite and hydrogen peroxide, potent oxidants produced during immune-cell mediated islet cell attack, trigger an intracellular cascade culminating in cellular energy failure. DNA strand-breakage triggered by hydrogen peroxide and peroxynitrite is recognized by a specific domain of the nuclear enzyme poly (ADP-ribose) synthetase (PARS). This results in the activation of PARS which initiates an energy consuming inefficient repair cycle, with resultant depletion of dinucleotide pools, slowing the rate of glycolysis and mitochondrial respiration, reducing ATP synthesis. Thus, PARS acts as a terminal mediator of cellular energetic collapse leading to cellular necrosis. The preliminary data show that pharmacological inhibition of PARS with 5-iodo-6-amino-1,2 benzopyrone (INH2BP), a novel, potent inhibitor of PARS reduces the development of hyperglycemia and islet cell destruction in a rot model of streptozotocin-induced diabetes. Furthermore, data from the group, and also from two other groups of investigators demonstrate that PARS deficient (knockout) mice are resistant against streptozotocin-induced diabetes. Because the streptozotocin-model is not fully predictable of the human situation, the first aim of the current protocol is aimed at investigating the role of PARS activation in the pathophysiology of spontaneous autoimmune diabetes: PARS deficient mice will be back-crossed with the NOD mice, and the development of diabetes will be investigated in this model. The course of pancreatic insulin depletion, the course of insulitis, and the development of hyperglycemia will be monitored. They will also test the effect of the PARS inhibitor INH2BP on the course of diabetes development in the NOD model. The second aim of the proposed studies is to perform in vitro studies in islets from wild type and PARS deficient mice in order to define the mode of cell death (necrosis and apoptosis) induced by peroxynitrite, and to define the role of PARS in the process. The current proposal will provide (1) novel mechanistic information on the mechanism of autoimmune diabetes, and (2) will result in data which will help the company in making a strategic decision for the preclinical development of a novel, potent, orally active PARS inhibitor.