Arginine Uptake Mechanisms Regulate Nitric Oxide in the Renal Vasculature

描述（由申请人提供）：一氧化氮（NO）通过影响全身血管阻力以及液体和电解质稳态来调节动脉血压和肾功能。尽管对这一主题进行了大量的研究，但在肾脏中NO产生的调节中重要的因素尚未明确定义。我们实验室的前期工作证明了L-精氨酸（L-Arg）摄取机制在肾上皮细胞中的重要性。令人兴奋的新的结果表明，从我们的实验室的细胞摄取的L-Arg，为NO合酶的底物，也是一个关键的调节剂，在肾血管内皮细胞的NO生产。因此，L-Arg摄取也是肾血管阻力的重要调节剂，对肾排泄功能产生影响。新的数据将表明，L-精氨酸运输机制有重要的影响，NO的生产和NO依赖的功能，在肾血管系统。使用这些新的数据作为一个基本原理和一个独特的综合实验方法，我们将定义的作用，L-精氨酸转运蛋白在体外和体内的肾血管功能的调节提供了一个了解的重要性，这种生理调节NO的生产。实验将检验一般假设，即肾血管内皮细胞中y+和y+L转运蛋白的细胞L-精氨酸摄取通过改变体内NOS底物的可用性来介导NO的产生，并在肾功能以及液体和电解质稳态的调节中起关键作用。这一假设将在三个具体目标中得到解决。具体目标1将利用独特的细胞和分子技术来确定肾血管中的L-Arg摄取机制和转运蛋白。目的2将采用新的方法来确定这些转运蛋白在肾血管系统中的功能的重要性，在体外和体内的NO生产和NO依赖的功能，在正常和患病动物。目标3中的实验然后将利用遗传操作的小鼠来确定哪种NOS同种型受细胞L-Arg摄取机制的影响。这种新的实验方法的组合将用于阐明L-Arg转运在调节肾血管阻力和肾功能中的重要作用。这些研究的结果可能为高血压和血管相关并发症的原因提供重要见解，这些并发症是美国死亡和发病的主要原因。

DESCRIPTION (provided by applicant): Nitric oxide (NO) regulates arterial blood pressure and kidney function by influencing systemic vascular resistance and fluid and electrolyte homeostasis. Despite the large amount of research on this subject, the factors important in the regulation of NO production in the kidney have not been clearly defined. Previous work from our laboratory demonstrated the importance of L-Arginine (L-Arg) uptake mechanisms in renal epithelial cells. Exciting new results from our laboratory indicate that cellular uptake of L-Arg, the substrate for NO synthase, is also a critical modulator of NO production in renal vascular endothelial cells. L-Arg uptake is therefore also an important regulator of renal vascular resistance with resulting effects on kidney excretory function. New data will be presented indicating that mechanisms of L-Arg transport have important effects on NO production and NO-dependent function in the renal vasculature. Using these novel data as a rationale and a unique integrative experimental approach, we will define the role of the L-Arg transporters in the regulation of renal vascular function in vitro and in vivo to provide an understanding of the importance of this physiological regulator of NO production. Experiments will test the General Hypothesis that cellular L-arginine uptake by y+ and y+L transporters in endothelial cells of the renal vasculature mediates the production of NO by altering the availability of NOS substrate in vivo and plays a critical role in the regulation of renal function as well as fluid and electrolyte homeostasis. This hypothesis will be addressed in three specific aims. Specific Aim 1 will utilize unique cellular and molecular techniques to identify the L-Arg uptake mechanisms and transporters in renal blood vessels. Aim 2 will employ novel methodology to determine the functional importance of these transporters in the renal vasculature on NO production and NO-dependent function both in vitro and in vivo in normal and diseased animals. Experiments in Aim 3 will then make use of genetically manipulated mice to determine which NOS isoform is affected by cellular L-Arg uptake mechanisms. This novel combination of experimental methods will be used to elucidate the important role of L-Arg transport in the regulation of renal vascular resistance and kidney function. The results of these studies may provide important insight into the causes of hypertension and vascular-related complications that are a leading cause of death and morbidity in the US.