Collecting duct endothelin and sodium homeostasis

集合管内皮素和钠稳态

• 批准号: 8002593
• 负责人: Donald E Kohan
• 金额: $ 51.5万
• 依托单位: AUGUSTA UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-08-06 至 2015-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8002593
• 关键词: Address; Antihypertensive Agents; Apical; Binding; Biology; Blood Pressure; Cell Culture Techniques; Cells; Coupled; Coupling; Data; Defect; Duct (organ) structure; Electrophysiology (science); Endothelin; Endothelin A Receptor; Endothelin B Receptor; Endothelin-1; Excretory function; Extracellular Fluid; Gene Targeting; Genes; Genetic Transcription; Genetically Engineered Mouse; Homeostasis; Hypertension; Kidney; Lead; Liquid substance; Mediating; Molecular; Mus; Pathway interactions; Physiological; Preparation; Probability; Production; Regulation; SRC gene; Signal Pathway; Signal Transduction; Sodium; System; Testing; Transcriptional Activation; Tubular formation; autocrine; base; cis acting element; epithelial Na+ channel; extracellular; polycystic kidney disease 1 protein; promoter; receptor; receptor coupling; response; saluretic; tool; Address; Antihypertensive Agents; Apical; Binding; Biology; Blood Pressure; Cell Culture Techniques; Cells; Coupled; Coupling; Data; Defect; Duct (organ) structure; Electrophysiology (science); Endothelin; Endothelin A Receptor; Endothelin B Receptor; Endothelin-1; Excretory function; Extracellular Fluid; Gene Targeting; Genes; Genetic Transcription; Genetically Engineered Mouse; Homeostasis; Hypertension; Kidney; Lead; Liquid substance; Mediating; Molecular; Mus; Pathway interactions; Physiological; Preparation; Probability; Production; Regulation; SRC gene; Signal Pathway; Signal Transduction; Sodium; System; Testing; Transcriptional Activation; Tubular formation; autocrine; base; cis acting element; epithelial Na+ channel; extracellular; polycystic kidney disease 1 protein; promoter; receptor; receptor coupling; response; saluretic; tool

The collecting duct (CD) endothelin system has emerged as an important regulator of renal Na excretion and systemic blood pressure (BP). CD-derived endothelin-1 (ET-1) exerts a hypotensive effect that is likely due, at least partly, to inhibition of the CD epithelial Na channel (ENaC). CD-derived ET-1 is important in mediating the natriuretic response to extracellular fluid volume (ECFV) expansion and controlling arterial BP; defects in the CD ET-1 system may contribute to hypertension. While the general biology of the CD ET system has been established, there remains much unknown about how this system functions. In particular, key components in critical need of study are: 1) determination if and how ET-1 inhibits CD Na transport; and 2) determination how ECFV status is coupled to CD ET-1 production. Based on preliminary data, the proposed studies will address the following hypotheses; ECFV expansion increases tubule fluid fiow rate through the CD. Increased fiow increases intracellular Ca concentration [Ca2+] through polycystins-1 and -2. Increased CD [Ca2+] induces signaling pathways causing transcriptional activation of the ET-1 gene. This increases CD ET-1 production and secretion resulting in autocrine activation of most likely the ETB receptor (ETRB), but also possibly the ETA receptor (ETRA). ET-1 binding leads to inhibition of the ENaC through reduction of channel open probability (Po) and possibly apical channel number (N). The effect on Po is due, at least partly, to activation of the c-src/MAPK pathway. The specific aims for this project include: Aim 1. Test the hypothesis that fiow stimulates CD ET-1 production, and that this effect is exerted by activation of specific cellular signaling pathways, cis-acting elements and trans-activating factors. Accordingly, we will: a) determine the effects of flow on CD ET-1 production; and b) determine the cellular signaling pathways, cis-acting elements and trans-activating factors coupling flow and intracellular Ca to ET-1 gene transcription. Aim 2. Test the hypothesis that ET-1 regulates ENaC in the CD, and that specific cellular and molecular mechanisms underpin this regulation. Accordingly, we will: a) determine if ET-1 regulates ENaC Po in native isolated CD cells; b) identify the specific ET receptor involved in regulating ENaC in native CD cells and elucidate the cellular signaling pathway coupling this receptor to the channel; c) define the importance of ET-1 regulation of CD ENaC in physiologic control of renal Na handling, and probe pathophysiological consequences of disrupting this regulation using gene targeted mice; and d) define the molecular mechanisms by which ET-1 modulates ENaC function, including identifying the specific residues/regions of ENaC that enable the channel to respond to ET-1.

收集管道（CD）内皮素系统已成为肾脏NA排泄的重要调节剂 和全身血压（BP）。 CD衍生的内皮素-1（ET-1）发挥了降压作用，可能是 至少部分归因于抑制CD上皮NA通道（ENAC）。 CD衍生的ET-1在 介导对细胞外流体体积（ECFV）膨胀和控制动脉BP的纳地尿症反应； CD ET-1系统中的缺陷可能导致高血压。而CD ET的一般生物学 已经建立了系统，关于该系统的运作方式尚不清楚。尤其， 迫切需要研究的关键组成部分是：1）确定ET-1是否以及如何抑制CD NA转运；和 2）确定如何将ECFV状态与CD ET-1产生结合。基于初步数据 拟议的研究将解决以下假设； ECFV膨胀增加了小管液率 通过CD。 FIOW增加可通过Polycystins -1和-2增加细胞内Ca浓度[Ca2+]。 增加的CD [Ca2+]诱导信号通路，导致ET-1基因转录激活。这 增加CD ET-1的产生和分泌，导致自分泌激活很可能ETB受体 （ETRB），但也可能是ETA受体（ETRA）。 ET-1结合通过降低通道开放概率（PO）和可能的顶通道数（n）来抑制ENAC。对PO的影响至少部分归因于C-SRC/MAPK途径的激活。该项目的具体目的包括： 目标1。检验以下假设，即FIOW刺激CD ET-1的产生，并且这种效应由 特定细胞信号通路，顺式作用元件和反式激活因子的激活。 因此，我们将：a）确定流动对CD ET-1产生的影响； b）确定细胞信号通路，顺式作用元件和跨激活因子耦合流以及细胞内CA与ET-1基因转录。 AIM 2。检验ET-1调节CD中ENAC的假设，以及该调节的特定细胞和分子机制。因此，我们将：a）确定ET-1是否调节天然分离的CD细胞中的ENAC PO； b）确定参与调节天然CD细胞ENAC的特定ET受体，并阐明该受体与通道的细胞信号传导途径； c）定义CD ENAC在肾脏NA处理的生理控制中的ET-1调节的重要性，以及使用基因靶向小鼠破坏这种调控的探针病理生理后果； d）定义ET-1调节ENAC功能的分子机制，包括识别ENAC的特定残基/区域，使通道能够对ET-1做出响应。