Role of Cytochrome P450 Eichosanoids in Pressure-Natriuresis

细胞色素 P450 类二十烷酸在压力尿钠中的作用

• 批准号: 8230995
• 负责人: Richard J. Roman
• 金额: $ 25.56万
• 依托单位: MEDICAL COLLEGE OF WISCONSIN
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-03-01 至 2013-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8230995
• 关键词: Alkane 1-monooxygenase; Alleles; Animal Model; Antihypertensive Agents; Attenuated; Biological Assay; Biological Models; Blood Pressure; Blood flow; CYP4A11 gene; Chromosomes, Human, Pair 5; Congenic Strain; Consomic Strain; Cytochrome P450; Data; Development; Experimental Models; Funding; Genes; Genetic; Genetic Models; Genetic Polymorphism; Goals; Human; Hydrostatic Pressure; Hydroxyeicosatetraenoic Acids; Hypertension; Kidney; Kidney Diseases; Measurement; Measures; Molecular Abnormality; Natriuresis; Pathway interactions; Play; Population; Production; Protein Isoforms; Proteins; Rat Strains; Rattus; Renal function; Role; Sodium; Techniques; Tern; Testing; Time; Transgenic Organisms; Variant; Work; drug development; enzyme activity; hypertension treatment; inhibitor/antagonist; interstitial; liquid chromatography mass spectrometry; man; novel; pressure; programs; response; salt sensitive; saluretic

Previous studies have indicated the kidney plays a dominant role in the long-tern control of arterial pressure and that the pressure-natriuresis relationship is shifted to higher pressures in every genetic and experimental model of hypertension that has been studied to date. However, the factors that alter renal function and the genes and pathways involved remain to be determined. Previous work done in this program revealed that pressure-natriuresis is associated with elevations in renal medullary blood flow and interstitial hydrostatic pressure (RIHP) and inhibition of Na+ transport in the proximal tubule. During the last funding period, we found that elevations in RIHP stimulate the renal formation of 20-HETE and that 20-HETE contributes to the pressure-natriuretic response by inhibiting sodium transport in the proximal tubule. We further demonstrated that blockade of the formation of 20-HETE promotes the development of salt-sensitive hypertension and obtained exciting new evidence that transfer of a 5 cM region of chromosome 5 containing the CYP4504A alleles from Lewis rats onto the Dahl salt-sensitive (SS) genetic background increases the renal expression of CYP4A protein and attenuates the development of hypertension. We now have preliminary data that transfer of chromosome 5 from the Brown Norwary (BN) rat onto the SS genetic background also opposes the development of hypertension in a SS.5BN consomic strain. These findings support our working hypothesis that a deficiency in the renal formation of 20-HETE contributes to the development of hypertension in SS rats. The goal of this project is to determine whether there is a sequence variant that reduces the activity or expression of one of the CYP4A genes in the kidney of SS rats and plays a causal role in the development of hypertension or if this pathway maybe secondarily involved because the expression of CYP4A isoforms are regulated by some other gene on chromosome 5. The Specific Aims are: 1) to determine whether the antihypertensive and renoprotective effects of transfer of chromosome 5 from the BN rat into the SS genetic background is dependent on an increase in the renal expression of CYP4A protein and the production of 20-HETE; 2) to determine if there is a sequence variant in one of the four CYP4A genes that reduces the expression or activity of these enzymes in the kidney of SS rats; and 3) to test if any of the sequence variants identified in the CYP4A genes contribute to the development of hypertension and renal disease in SS rats using transgenic techniques. The novel aspects of these studies are that they will employ unique chromosome 5 congenic and consomic strains of SS rats that we developed over the last 5 years, a new LC/MS/MS assay for measurement of 20-HETE, novel inhibitors of the synthesis and actions of 20-HETE, real time-PCR assays for measuring the expression of CYP4A isoforms and a new lentiviral strategy for creating transgenic strains of rats The proposed studies to determine if a genetic abnormality in the renal formation of 20-HETE contributes to the development of hypertension in SS rats by resetting the pressure-natriuretic relationship are especially unique and relevant, since a polymorphism in the CYP4A11 gene that reduces the formation of 20-HETE has recently been associated with elevated blood pressure in three independent human populations.(77,183,184) These studies will provide a new homologous animal model system to explore mechanisms to explain how a deficiency in the renal formation of 20-HETE could contribute to the development of salt-sensitive forms of hypertension in man. The results obtained may also spur the development of drugs that upregulate this pathway for the treatment of hypertension and renal disease.

先前的研究表明，肾脏在动脉压的长端控制中起主要作用，并且在迄今为止研究的每种遗传和实验性高血压模型中，压力 - 纳他的关系都转移到了更高的压力上。但是，改变肾功能以及所涉及的基因和途径的因素仍有待确定。该计划中所做的先前工作表明，压力纳他尿素与肾脏血流和间质静水压力（RIHP）（RIHP）的升高以及近端小管中Na+转运的抑制有关。在最后一个资金期间，我们发现RIHP的升高刺激了20-HETE的肾脏形成，而20-HETE则通过抑制近端小管中的钠转运来促进压力 - 纳他尿素反应。我们进一步证明，封锁20-HETE会促进盐敏感高血压的发展和 获得了令人兴奋的新证据，表明将含有CYP4504A等位基因的5厘米染色体区域转移到刘易斯大鼠到达尔盐敏感（SS）遗传背景会增加CYP4A蛋白的肾脏表达并减轻高血压的发展。现在，我们有了转移的初步数据 来自棕色诺瓦里（BN）大鼠到SS遗传背景的5号染色体也相反，在5亿SS的配音菌株中发展了高血压。这些发现支持我们的工作假设，即20-HETE肾脏形成的缺乏有助于SS大鼠的高血压发展。该项目的目的是确定是否有一个序列变体可以减少活动或 SS大鼠肾脏中CYP4A基因之一的表达在高血压发展中起因果作用，或者是否涉及该途径，因为CYP4A同工型的表达受到染色体5的其他基因的调节。 CYP4A蛋白的肾脏表达增加和20-HETE的产生； 2）确定四个CYP4A基因之一中是否存在序列变体，可以降低SS大鼠肾脏中这些酶的表达或活性； 3）测试CYP4A基因中鉴定出的任何序列变体是否有助于使用转基因技术在SS大鼠中的高血压和肾脏疾病的发展。这些研究的新方面是，它们将采用我们过去5年中开发的SS大鼠的独特染色体和综合菌株，这是一个新的 LC/MS/MS assay for measurement of 20-HETE, novel inhibitors of the synthesis and actions of 20-HETE, real time-PCR assays for measuring the expression of CYP4A isoforms and a new lentiviral strategy for creating transgenic strains of rats The proposed studies to determine if a genetic abnormality in the renal formation of 20-HETE contributes to the development of hypertension in SS rats by resetting the pressure-natriuretic relationship are especially unique and relevant, since a polymorphism in the CYP4A11 gene that reduces the formation of 20-HETE has recently been associated with elevated blood pressure in three independent human populations.(77,183,184) These studies will provide a new homologous animal model system to explore mechanisms to explain how a deficiency in the renal formation of 20-HETE could contribute to the development of salt-sensitive forms of人类的高血压。获得的结果也可能刺激 开发用于上调这一治疗高血压和肾脏疾病的途径的药物。