20-HETE and EETs in pressure natriuresis

20-HETE 和 EET 在压力尿钠中的作用

• 批准号: 7367208
• 负责人: Richard J. Roman
• 金额: $ 30.25万
• 依托单位: MEDICAL COLLEGE OF WISCONSIN
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-03-01 至 2008-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7367208
• 关键词: Acids; Acute; Address; Agonist; Antihypertensive Agents; Arachidonic Acids; Attenuated; Binding; Biological Assay; Blood Pressure; Blood Vessels; Blood flow; Chronic; Clinical; Collaborations; Cytochrome P450; Cytochromes; Development; Elevation; Enzyme Inhibitor Drugs; Enzyme Inhibitors; Enzymes; Experimental Genetics; Experimental Models; Fibrates; Henle' s loop; High Pressure Liquid Chromatography; Hydrostatic Pressure; Hydroxyeicosatetraenoic Acids; Hypertension; Infusion procedures; Intake; Intercellular Fluid; Kidney; Kidney Diseases; Laboratories; Measures; Mediating; Mediator of activation protein; Methods; Microdialysis; Modeling; Natriuresis; Nephrons; Oxidative Stress; Oxygen; Pathway interactions; Perfusion; Pharmacologic Substance; Play; Production; Proximal Kidney Tubules; Rat Strains; Rattus; Reactive Oxygen Species; Renal Blood Flow; Renal Hypertension; Renal function; Renal tubule structure; Research; Resistance; Role; Signal Transduction; Stress; Superoxide Dismutase; Superoxides; System; Thick; Tissues; Tubular formation; Vitamin E; Wit; Work; antioxidant therapy; apical membrane; base; concept; in vivo; inhibitor/antagonist; interstitial; liquid chromatography mass spectrometry; normotensive; novel; pressure; response; salt sensitive; tempol; tool

The concept that the kidney plays a dominant role in the long-term control of arterial pressure is based on the pressure-natriuresis. Previous work by our laboratory has indicated that pressure-natriuresis is associated with inhibition of Na+ transport in the proximal tubule and the loop of Henle and identified an important role for elevations in renal medullary blood flow and renal interstitial hydrostatic pressure (RIHP) in signaling this response. However, the mechanism by which elevations in renal perfusion pressure (RPP) and/or RIHP inhibit Na transport is unknown and remains a key unanswered question in hypertension research. Recent studies by our lab and others have revealed that arachidonic acid is primarily metabolized by cytochrome P450 (CYP) enzymes to 20-hydroxyeicosatetraenoic acid (20-HETE) and epoxyeicosatrienoic acids (EETs) in the proximal tubule and TALH where these compounds regulate Na+ transport. Thus, the present study will examine the hypothesis that elevations in RPP (through changes in RIHP) increase the production of 20-HETE and/or EETs in the proximal and TALH and that these compounds mediate pressure-natriuresis by inhibiting Na+transport in these nephron segments. Aim 1 will determine whether elevations in RPP and RIHP increase the levels of EETs and 20-HETE in renal interstitial fluid and cortical and medullary tissue using in vivo microdialysis and new fluorescent HPLC and LC/MS assays that we developed for measuring EETs and 20-HETE. Aim 2 will examine the effects of acute and chronic blockade of the synthesis or actions of EETs and 20-HETE on pressure natriuresis and Na in the proximal tubule and TALH using in vivo tubular perfusion. These studies will take advantage of novel specific inhibitors of the synthesis and actions of 20-HETE and EETs that we recently developed in collaboration with Dr. Falck and Tashio Pharmaceutical Corp. This aim will also examine whether 20-HETE and EETs mediate the inhibitory effects of elevations in RPP on Na by inhibiting Na+-K in the proximal tubule and TALH or by altering the distribution of Na+ transporters in the apical membranes of these nephron segments. Aim 3 will characterize the effects of elevations in Na on the levels of EETs and 20-HETE in the kidney of salt-sensitive and salt-resistant strains of rats and whether chronic blockade of the formation of 20-HETE and/or EETs blunts pressure-natriuresis and promotes the development of salt-sensitive hypertension in normotensive strains of rats. Aim 4 will determine if reactive oxygen species (ROS) inhibit the synthesis and enhance the degradation of CYP metabolites of AA in the kidney and whether elevations in the renal levels of CYP metabolites of AA contribute to the antihypertensive effects of antioxidant therapy (TEMPOL or vitamin E) in Dahl SS/Mcw rats. This aim will also examine if ROS-induced decreases in the renal levels of 20-HETE and/or EETs contribute to the development of hypertension in salt-resistant strains of rats when renal oxidative stress is elevated by a chronic renal medullary infusion of the superoxide dismutase inhibitor, DETC. Overall, these studies will provide new information regarding the role of CYP metabolites of AA in renal function, pressure-natriuresis and the long-term control of arterial pressure and the potential interactions of this system in mediating some of the deterimental effects of ROS on renal function. This information will likely provide a strong rationale for the clinical development of inducers of the formation of 20-HETE and/or EETs (fibrates) and stable 20-HETE and EET agonists as new theraputic approaches for the treatment of hypertension and renal disease.

肾脏在动脉压的长期控制中起主要作用的概念是基于压力 - 纳二硫酸盐。我们的实验室的先前工作表明，压力纳他尿液与近端小管中Na+转运的抑制有关，并确定了肾脏髓质血流和肾脏间质性静水压（RIHP）在信号中的升高中的重要作用。但是，肾脏灌注压力（RPP）和/或RIHP抑制NA转运的机制尚不清楚，并且在高血压研究中仍然是一个关键的未解决问题。我们的实验室和其他人的最新研究表明，蛛网膜酸主要是由细胞色素P450（CYP）酶代谢为20-羟基羟基乙烯烯酸（20-甲基）和环氧化含量（EET）（EET）（EET）（EET），这些含量在这些近端管道和TALH中构成了NA的调节。因此，本研究将研究以下假设：RPP的升高（通过RIHP的变化）增加了近端和TALH中20-HETE和/或EET的产生 这些化合物通过抑制这些肾单位段中的Na+转运来介导压阳离子。 AIM 1将确定RPP和RIHP的升高是否会增加使用体内微透析中的Eets和20-HETE的肾脏间质液以及皮质和髓质组织的水平，以及我们开发用于测量Eets和20-Hete的新荧光HPLC和LC/​​MS分析。 AIM 2将检查急性和慢性阻断EET的急性和慢性封锁和20-HETE对近端小管的压力Natriuresis和Na的作用的影响 使用体内管状灌注。 These studies will take advantage of novel specific inhibitors of the synthesis and actions of 20-HETE and EETs that we recently developed in collaboration with Dr. Falck and Tashio Pharmaceutical Corp. This aim will also examine whether 20-HETE and EETs mediate the inhibitory effects of elevations in RPP on Na by inhibiting Na+-K in the proximal tubule and TALH or by altering the distribution of Na+ transporters in the apical membranes of these肾单位段。 AIM 3将表征NA的高程对大鼠盐敏感和耐盐的抗菌菌株的Eets和20-Hete水平的影响 压力催生并促进正常大鼠菌株中盐敏感性高血压的发展。 AIM 4将确定活性氧（ROS）是否抑制了肾脏中AA的CYP代谢物的合成并增强降解，以及AA肾脏CYP代谢产物的升高是否有助于抗氧化治疗（Tempol或Vivamin e）在Dahlls/McW中的抗近型抗激素作用。这个目标也将 检查ROS诱导的20-HETE和/或EET的肾脏水平的降低是否有助于当肾脏氧化应激通过慢性肾脏髓样在上氧化物歧化酶抑制剂抑制剂detc升高时，有助于大鼠盐耐盐菌株的高血压发育。总体而言，这些研究将提供有关AA的CYP代谢产物在肾功能，压力 - 纳他的作用以及对动脉压的长期控制以及该系统在介导ROS对肾功能的某些恶化作用中的作用的新信息。这些信息可能会为诱导者的临床发展提供了有力的基本原理，作为治疗高血压和肾脏疾病的新治疗方法，诱导者的形成20-HETE和/或EET（纤维）和稳定的20-Hete和Eet激动剂。