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和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，但在肾脏中调节NO产生的重要因素尚未明确定义。我们实验室之前的工作证明了l -精氨酸（L-Arg）摄取机制在肾上皮细胞中的重要性。我们实验室令人兴奋的新结果表明，细胞摄取l -精氨酸（NO合成酶的底物）也是肾血管内皮细胞NO生成的关键调节剂。因此，l -精氨酸摄取也是肾血管阻力的重要调节因子，从而影响肾脏排泄功能。新的数据将表明，L-Arg转运机制对肾血管中NO的产生和NO依赖功能有重要影响。利用这些新数据作为理论基础和独特的综合实验方法，我们将定义l -精氨酸转运体在体外和体内肾血管功能调节中的作用，以了解这种生理调节NO产生的重要性。实验将验证一般假设，即肾血管内皮细胞中y+和y+L转运体对L-精氨酸的摄取通过改变体内NOS底物的可用性来介导NO的产生，并在肾脏功能以及体液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。Specific Aim 1将利用独特的细胞和分子技术来鉴定肾血管中的l -精氨酸摄取机制和转运体。目的2将采用新颖的方法来确定这些转运蛋白在正常和患病动物体内和体外对一氧化氮生成和一氧化氮依赖功能的功能重要性。Aim 3的实验将利用转基因小鼠来确定哪种NOS异构体受到细胞l -精氨酸摄取机制的影响。这种新颖的实验方法组合将用于阐明l -精氨酸转运在肾血管阻力和肾功能调节中的重要作用。这些研究的结果可能为高血压和血管相关并发症的病因提供重要的见解，而高血压和血管相关并发症是美国死亡和发病率的主要原因。

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.