Renal Cortical Oxidative & Nitrosative Stress in IDDM

在大鼠1型糖尿病（DM）早期，超氧阴离子（O2 -）的产生加速了一氧化氮（NO）通过过氧亚硝酸盐（ONOO）的降解。形成，导致蛋白质酪氨酸硝化和血管反应性的改变。糖尿病患者肾脏氧化应激的发生机制尚未明确。我们已经发现，患有DM的大鼠表现出循环血管紧张素II（AngII）水平和AngII 1型（AT 1）受体蛋白的肾皮质水平的显著增加。AT 1受体激活可以激发O2。 通过NAD（P）H氧化酶活化产生。我们还发现DM大鼠肾皮质中Hsp 90水平降低的证据。 新出现的证据表明，Hsp 90代表了NO产生的重要步骤，至少部分地限制了O2。NO合成酶（NOS）。在这些初步观察的基础上，我们假设，NAD（P）H氧化酶激活和NOS解偶联有助于糖尿病肾皮质氧化和亚硝化应激，从而影响NO的生物利用度和行动，最终减少其对肾功能的影响。将利用大鼠中STZ诱导的DM模型来评估：1）AngII依赖性NAD（P）H氧化酶活化在肾皮质O2中的作用。 2）Hsp 90或BH 4依赖的NOS解偶联蛋白9对糖尿病肾损害的作用。 皮质氧含量3）鸟苷酸环化酶酪氨酸硝化在糖尿病肾微血管功能改变中的潜在作用。根据RFA-DK-O2-O23的雅阁，该应用程序请求支持两个独立的、已建立的研究者之间的合作伙伴关系- Pamela K。Carmines（一位专门研究糖尿病肾脏微血管并发症的肾脏生理学家）和Jennifer S.波洛克（一位蛋白质化学家，在NOS方面有特殊的专长）。Carmines博士和Pollock博士最近在一份联合出版物中记录了他们作为合作者的成功，为该项目提供了许多初步数据。完成拟议的工作应定位波洛克博士作为一个积极的糖尿病研究人员。对这一研究伙伴关系的资助也将加强Carmines博士实验室正在进行的努力，促进获得专门知识和技术，这些知识和技术是对她的实验室目前可用于研究糖尿病肾微血管功能和氧化应激的补充。因此，拟议的合作允许生物化学，细胞和功能方法，可以揭示治疗干预的新靶点，限制DM早期阶段氧化和亚硝化应激的发展或后果， 延缓或预防糖尿病肾病的发展。

During the early stage of type 1 diabetes mellitus (DM) in the rat, accelerated superoxide anion (O2 -) production fuels degradation of nitric oxide (NO) via peroxynitrite (ONOO.) formation, resulting in protein tyrosine nitration and alterations in vascular reactivity. The mechanisms engendering renal oxidative stress in DM have not been established. We have found that rats with DM exhibit significant increases in both circulating angiotensin II (Angll) levels and renal cortical levels of the Angll type 1 (AT 1) receptor protein. AT 1 receptor activation can provoke O2.- production via NAD(P)H oxidase activation. We have also found evidence of reduced Hsp90 levels in the renal cortex of rats with DM. Emerging evidence indicates that Hsp90 represents an essential step in NO production, functioning at least in part to limit O2.- production by NO synthase (NOS). On the basis of these preliminary observations, we hypothesize that NAD(P)H oxidase activation and NOS-uncoupling contribute to renal cortical oxidative and nitrosative stress in DM, with consequent effects on NO bioavailability and action that ultimately diminish its impact on renal function. The STZ-induced model of DM in the rat will be utilized to evaluate: 1) the role of Angll-dependent NAD(P)H oxidase activation in the renal cortical O2.- production during DM; 2) the contribution of Hsp90- or BH4-dependent NOS-uncouplin9 to renal cortical O2.- production during DM; and 3) the potential role of tyrosine nitration of guanylyl cyclase in altering in renal microvascular function during DM. Tin accord with RFA-DK-O2-O23, this application requests support for a collaborative partnership between two independent, established investigators - Pamela K. Carmines (a renal physiologist with expertise in the renal microvascular complications of DM)) and Jennifer S. Pollock (a protein chemist with particular expertise in NOS). Drs. Carmines and Pollock recently documented their success as collaborators in a joint publication providing much of the preliminary data for this project. Completion of the proposed work should position Dr. Pollock as an active diabetes researcher. Funding of this research partnership would also strengthen the ongoing efforts of Dr. Carmines' laboratory by facilitating access to expertise and technologies that are complementary to those currently available to her laboratory for studies of renal microvascular function and oxidative stress in DM. The proposed collaboration thus allows a biochemical, cellular, and functional approach that could unveil novel targets for therapeutic interventions that limit the development or consequences of oxidative and nitrosative stress during the early stage of DM, thereby delaying or preventing development of diabetic nephropathy.