Renal Vascular Reactivity in Hypertension

高血压中的肾血管反应性

基本信息

批准号：
8383467
负责人：
WILLIAM J ARENDSHORST
金额：
$ 56.06万
依托单位：
UNIV OF NORTH CAROLINA CHAPEL HILL
依托单位国家：
美国
项目类别：
财政年份：
1986
资助国家：
美国
起止时间：
1986-09-01 至 2014-11-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8383467
关键词：
ADP-ribosyl Cyclase Abnormal Cell Acute Adenosine Diphosphate Affinity Agonist American Angiotensin II Animals Arteries Atherosclerosis Attenuated Binding Blood Vessels Blood Volume Chronic Conscious Contracts Development Diabetes Mellitus Dinoprost Disease Endothelin Endothelin-1 Enzymes Event Excretory function Exhibits Family member Flowmetry Funding G-Protein-Coupled Receptors Gene Targeting Genetic Goals Health Hormones Hypertension Image Infusion procedures Ion Channel Isoprostanes Kidney Kidney Failure Knock-out Knockout Mice Measures Mediating Membrane Messenger RNA Microcirculation Modeling Molecular Mus NAD+ Nucleosidase Natriuresis Nitrates Nitric Oxide Nitrites Oxidative Stress Pathogenesis Pathway interactions Phase Physiological Physiology Play Positioning Attribute Production Regulation Renal function Resistance Role Ryanodine Receptors Second Messenger Systems Severities Signal Pathway Signal Transduction Small Interfering RNA Smooth Muscle Myocytes Sodium Chloride Stroke System Telemetry Testing Thromboxane Receptor Thromboxanes Ultrasonics Vascular Diseases Vasoconstrictor Agents Water Wild Type Mouse Work arteriole blood pressure regulation calcium metabolism cardiovascular risk factor density genetic manipulation in vivo kidney cortex kidney vascular structure knock-down novel pressure radioligand receptor response tool urinary vasoconstriction

项目摘要

ABSTRACT CD38 ADP ribosyl (ADPR) cyclase is a membrane-bound enzyme that produces metabolites known to promote Ca2+ mobilization mediated by ryanodine receptors (RyR) in arteriolar smooth muscle cells. We posit that renal CD38 is central to the development of angiotensin II (Ang II)-induced hypertension (AIH) and that CD38-deficient mice exhibit less pronounced renal vasoconstriction, Na+ retention and AIH than do wild-type (WT) mice. AIM 1 tests the hypothesis that CD38 ADPR cyclase participates in the development of AIH such that Ang II produces less pronounced hypertension in CD38-/- (global genetic deficiency) vs. WT mice. Less severe hypertension is also predicted in WT mice with targeted, renal-specific partial knockdown of CD38 induced by siRNA. The severity of AIH is determined by measuring 24-hr arterial pressure (telemetry) in conscious, unrestrained mice before and during chronic Ang II infusion. Also measured are 24 hr urinary excretion of nitrite/nitrate and 8-iso-PGF2¿ to assess nitric oxide (NO) production and oxidative stress. CD38 mRNA and ADPR cyclase activity will be quantified in preglomerular vessels. AIM 2 assesses the contribution of CD38 ADPR cyclase to renal vasoconstriction and the rightward shift in the pressure-natriuresis relation in AIH. We predict that the kidneys of CD38-deficient mice excrete Na+ more rapidly in response to an acute salt load than WT mice during development of AIH, with excretion rates becoming similar in established AIH. Conscious and anesthetized mice with global knockout and renal-specific knockdown of CD38 will be evaluated in both phases. AIM 3 evaluates the hypothesis that CD38 is the major ADPR cyclase mediating G- protein coupled receptor-elicited Ca2+ signaling involving RyR and Ca2+-induced Ca2+ release in isolated afferent arterioles and renal vasoconstriction in vivo. We predict that Ca2+ signaling and vascular responsiveness to vasoconstrictor agents (Ang II, ET-1, TxA2) are attenuated in CD38-deficient vs. WT mice during control and AIH conditions. Scatchard analysis of radioligand binding will characterize Ang II, ET-1, and TP receptor affinity and/or density in renal microvessels. Our goal is to identify a sequence of events that precede or occur early during the development of hypertension and thus are more likely to be causative than secondary, pressure-dependent consequences. Combining gene-targeted deletion of CD38, global and renal- specific, with pharmacological inhibition of ADPR cyclase and RyR-mediated Ca2+ release will provide important new information that CD38 is the primary cyclase family member mediating Ca2+ signaling in the renal microcirculation and its functional significance in long-term regulation of renal vasoconstriction, Na+ retention and the development of AIH. Successful completion of our novel studies of this underappreciated pathway will significantly advance our understanding of cellular/molecular mechanisms of Ca2+ signaling in the renal microcirculation and regulation of renal vascular reactivity in health and disease, making a major impact on the field.

抽象的 CD38 ADP 核糖基 (ADPR) 环化酶是一种膜结合酶，可产生已知的代谢物促进小动脉平滑肌细胞中兰尼碱受体 (RyR) 介导的 Ca2+ 动员。 CD38 是血管紧张素 II (Ang II) 诱导的高血压 (AIH) 发展的核心，并且与野生型相比，CD38 缺陷小鼠的肾血管收缩、Na+ 潴留和 AIH 表现出不太明显 (WT) 小鼠测试了 CD38 ADPR 环化酶参与 AIH 发展的假设。与 WT 小鼠相比，Ang II 在 CD38-/-（整体遗传缺陷）小鼠中产生的高血压不太明显。通过靶向、肾脏特异性部分敲除 CD38 的 WT 小鼠也可预测严重高血压 AIH 的严重程度是通过测量 24 小时动脉压（遥测）来确定的。在慢性 Ang II 输注之前和期间，还测量了清醒、不受约束的小鼠的 24 小时尿量。亚硝酸盐/硝酸盐和 8-iso-PGF2 的排泄¿评估一氧化氮 (NO) 的产生和氧化应激。 AIM 2 将对肾小球前血管中的 mRNA 和 ADPR 环化酶活性进行定量评估。 CD38 ADPR 环化酶对肾血管收缩的影响以及压力-尿钠排泄关系的右移我们预测，CD38 缺陷小鼠的肾脏对急性盐的反应会更快地排泄 Na+。在 AIH 的发展过程中，其负荷量高于 WT 小鼠，并且在已建立的 AIH 中排泄率变得相似。具有 CD38 整体敲除和肾脏特异性敲除的清醒且麻醉的小鼠将被 AIM 3 评估 CD38 是介导 G- 的主要 ADPR 环化酶的假设。蛋白质偶联受体诱导的 Ca2+ 信号转导 RyR 和 Ca2+ 诱导的 Ca2+ 释放涉及分离的我们预测 Ca2+ 信号传导和体内血管收缩。与 WT 小鼠相比，CD38 缺陷小鼠对血管收缩剂（Ang II、ET-1、TxA2）的反应减弱在对照和 AIH 条件下，放射性配体结合的 Scatchard 分析将表征 Ang II、ET-1、我们的目标是确定肾微血管中 TP 受体亲和力和/或密度。在高血压发展之前或早期发生，因此更有可能是高血压的病因结合基因靶向删除 CD38、整体和肾功能的次要后果。具体而言，通过药理学抑制 ADPR 环化酶和 RyR 介导的 Ca2+ 释放将提供重要的新信息表明 CD38 是介导 Ca2+ 信号传导的主要环化酶家族成员肾微循环及其在肾血管收缩长期调节中的功能意义，Na+ AIH 的保留和发展成功完成了我们对这一未被充分重视的新颖研究。途径将显着促进我们对 Ca2+ 信号传导的细胞/分子机制的理解肾微循环和肾血管反应性的调节对健康和疾病产生重大影响在球场上。