CYTOCHROME P-450 ARACHIDONIC ACID METABOLISM & REGULATION OF RENAL ION TRANSPORT

CYTOCHROME P-450 花生四烯酸代谢

• 批准号: 6564251
• 负责人: Matthew Douglas Breyer
• 金额: $ 16.26万
• 依托单位: VANDERBILT UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-12-01 至 2002-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6564251
• 关键词: cyclic AMP; cytochrome P450; eicosanoid metabolism; ion transport; isozymes; kidney function; laboratory mouse; laboratory rabbit; peroxisome; polymerase chain reaction; prostaglandin endoperoxide synthase; prostaglandin inhibitors; prostaglandin receptor; renal tubular transport; sodium ion; tissue /cell culture; troglitazone; western blottings

The renal metabolism of arachidonic acid (AA) produces a diverse array of biologically active lipid mediators which potently regulate renal hemodynamics and ion transport along the nephron. Cyclooxygenase mediated prostanoid formation has been extensively studied and an important physiologic role, established. The kidney also possess a robust cytochrome P450 (CYP450) system which rapidly metabolizes arachidonate to several bioactive lipids including the epoxyeicosatrienoic acids (EETs) and omega/omega-1 AA metabolites (the hydroxyeicosatetraenoic acids or HETEs). Accumulating evidence supports an intimal association between renal CYP450 activity and the regulation of systemic blood pressure. Inhibition of renal CYP450 activity induces hypertension and the CYP450 AA metabolite, 20-HETE inhibits CI-absorption in the thick ascending limb (TAL). 20-HETE is actively formed by only a few CYP450s, and the CYP4A family appear to be the relevant isoforms in the kidney. In specific aim #1 we propose to characterize the role of specific CYP4A isoforms and their omega/omega-1 AA metabolites in regulating ion transport to murine microperfused thick ascending limbs (TAL). Studies in mice with targeted disruption of CYP4A10 and 4A14 should allow us to define roles for specific CYP450 isoforms in regulating TAL ion transport. The expression of CYP4As has recently been shown to be under the control of a fatty acid activated transcription factor, known as peroxisome proliferator activated receptor alpha (PPARalpha). We have recently mapped the intra-renal expression of three PPAR isoforms (PPARalpha, gamma, and delta) and find PPARalpha is highly expressed in proximal tubule and TAL, whereas PPARgamma is primarily expressed in the collecting duct. Preliminary data suggests activation and TAL, whereas PPARgamma enhances Na+ absorption in collecting duct. In specific aim #2, we propose to characterize the effects of PPAR activation on epithelial Na+ transport in cultured cortical collecting ducts (CCDs) as well as in whole animal Na+ balance studies. Finally, the production of the EETs is mediated by distinct families of CYP450s including CYP2C and CYP2B isoforms Evidence suggests 5,6-EET and 14,15-EET potently regulate transport in the renal collecting duct. In specific aim #3 we propose to further examine the role of CYP450 AA epoxygenases in regulating ion transport along the nephron. Roles for the prostaglandin EP1 receptor in mediating the effect of 5,6-EET in microperfused CCDs will be tested, as will effects of adenoviral mediated CYP450 expression on transport in cultured CCDs. It is our hope these studies will help define the role of CYP450-AA metabolism in regulating renal ion transport, its impact on Na+ excretion, and ultimately the control of systemic blood pressure.

蛛网膜酸（AA）的肾脏代谢产生了多种多样的阵列 有效调节肾脏的生物活性脂质介质 血液动力学和离子沿着肾单位转运。环氧酶介导的 前列腺素的形成已经进行了广泛的研究，并且很重要 生理角色，建立。肾脏还具有强大的细胞色素 P450（CYP450）系统迅速代谢蛛网 生物活性脂质在内 Omega/Omega-1 AA代谢产物（羟基乙烯酸或HETES）。 积累的证据支持肾脏CYP450之间的直接关联 活性和全身血压的调节。抑制 肾脏CYP450活性诱导高血压和CYP450 AA代谢物， 20-Hete抑制厚升肢（TAL）中的CI吸收。 20-hete 仅由几个CYP450积极形成，CYP4A家族似乎 成为肾脏中相关的同工型。在特定目标＃1中，我们建议 表征特定CYP4A同工型及其Omega/Omega-1的作用 AA代谢产物在调节离子转运到鼠微体厚的厚度 上升的四肢（TAL）。在针对CYP4A10靶向破坏的小鼠中的研究 4A14应允许我们定义特定CYP450同工型的角色 调节塔尔离子运输。 CYP4A的表达最近已经 被证明在脂肪酸激活转录的控制之下 因子，称为过氧化物酶体增殖物激活受体α （pparalpha）。我们最近绘制了三个的肾脏内表达 PPAR同工型（Pparalpha，Gamma和Delta），找到PPARALPHA高度 在近端小管和TAL中表达，而Ppargamma主要是 在收集管中表达。初步数据表明激活和 TAL，而ppargamma在收集管道中增强了Na+吸收。在 特定目标＃2，我们建议表征PPAR激活的影响 在培养的皮质收集管（CCD）中上皮Na+转运 以及整个动物NA+平衡研究。最后，生产 EET由包括CYP2C和包括CYP450的不同家族介导 CYP2B同工型证据表明，有5,6-EET和14,15-EET有效调节 在肾脏收集管道中的运输。在特定目标＃3中，我们建议 进一步研究CYP450 AA环氧酶在调节离子中的作用 沿着肾脏运输。前列腺素EP1受体的作用 将测试介导5,6-EET在微填充CCD中的效果，例如 将对腺病毒介导的CYP450表达对运输的影响 培养的CCD。我们希望这些研究将有助于定义 CYP450-AA代谢在调节肾离子运输中，其对Na+的影响 排泄，最终控制全身血压。