Renal Vascular Reactivity in Hypertension

高血压中的肾血管反应性

基本信息

批准号：
8050304
负责人：
WILLIAM J ARENDSHORST
金额：
$ 57.43万
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/8050304
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 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

DESCRIPTION (provided by applicant): 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-PGF21 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. PUBLIC HEALTH RELEVANCE: More than 70 million Americans have hypertension, a major cardiovascular risk factor, highly predictive of other vascular diseases such as atherosclerosis, diabetes mellitus, renal failure, and stroke. Studies are proposed to investigate mechanisms regulating calcium metabolism in smooth muscle cells that contract blood vessels. Abnormal cell signaling can cause arteries to be hyper-responsive to vasoactive hormones and cause the kidneys to retain inappropriate amounts of salt and water, resulting in an expanded blood volume and the development of high blood pressure.

描述（由申请人提供）：CD38 ADP 核糖基 (ADPR) 环化酶是一种膜结合酶，其产生的代谢物已知可促进小动脉平滑肌细胞中兰尼碱受体 (RyR) 介导的 Ca2+ 动员。我们假设肾脏 CD38 对于血管紧张素 II (Ang II) 诱导的高血压 (AIH) 的发展至关重要，并且与野生型 (WT) 小鼠相比，CD38 缺陷小鼠表现出较不明显的肾血管收缩、Na + 潴留和 AIH。 AIM 1 测试了以下假设：CD38 ADPR 环化酶参与 AIH 的发展，因此与 WT 小鼠相比，Ang II 在 CD38-/-（整体遗传缺陷）小鼠中产生不太明显的高血压。通过 siRNA 诱导的 CD38 的靶向、肾脏特异性部分敲低，WT 小鼠中的高血压也有望减轻。 AIH 的严重程度是通过在慢性 Ang II 输注之前和期间测量清醒、不受约束的小鼠的 24 小时动脉压（遥测）来确定的。还测量了 24 小时尿中亚硝酸盐/硝酸盐和 8-iso-PGF21 的排泄量，以评估一氧化氮 (NO) 的产生和氧化应激。 CD38 mRNA 和 ADPR 环化酶活性将在肾小球前血管中进行定量。 AIM 2 评估 CD38 ADPR 环化酶对肾血管收缩的贡献以及 AIH 中压力-尿钠排泄关系的右移。我们预测，在 AIH 发展过程中，CD38 缺陷型小鼠的肾脏对急性盐负荷的反应比 WT 小鼠更快地排泄 Na+，并且排泄率在已形成的 AIH 中变得相似。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在两个阶段进行评估。 AIM 3 评估了以下假设：CD38 是主要的 ADPR 环化酶，介导 G 蛋白偶联受体引发的 Ca2+ 信号传导，涉及 RyR 和 Ca2+ 诱导的孤立传入小动脉中的 Ca2+ 释放和体内肾血管收缩。我们预测，在对照和 AIH 条件下，CD38 缺陷小鼠与 WT 小鼠相比，Ca2+ 信号传导和血管对血管收缩剂（Ang II、ET-1、TxA2）的反应性减弱。放射性配体结合的 Scatchard 分析将表征肾微血管中 Ang II、ET-1 和 TP 受体亲和力和/或密度。我们的目标是确定高血压发展之前或早期发生的一系列事件，因此这些事件更有可能是导致高血压的原因，而不是次要的、与压力相关的后果。将 CD38 的基因靶向缺失（整体和肾脏特异性）与 ADPR 环化酶和 RyR 介导的 Ca2+ 释放的药理学抑制相结合，将提供重要的新信息，即 CD38 是介导肾微循环中 Ca2+ 信号传导的主要环化酶家族成员及其功能意义长期调节肾血管收缩、Na+潴留和 AIH 的发展。我们对这一未被充分重视的途径的新研究的成功完成将显着促进我们对肾脏微循环中 Ca2+ 信号传导的细胞/分子机制以及健康和疾病中肾血管反应性调节的理解，从而对该领域产生重大影响。公共卫生相关性：超过 7000 万美国人患有高血压，这是一种主要的心血管危险因素，高度预测其他血管疾病，如动脉粥样硬化、糖尿病、肾衰竭和中风。拟议研究调查调节收缩血管的平滑肌细胞中钙代谢的机制。异常的细胞信号传导会导致动脉对血管活性激素过度反应，并导致肾脏保留不适当量的盐和水，导致血容量增加和高血压的发生。