Calcium sparklets-induced vascular dysfunction during diabetes

糖尿病期间钙火花诱导的血管功能障碍

• 批准号: 7982925
• 负责人: Manuel F Navedo
• 金额: $ 39万
• 依托单位: UNIVERSITY OF WASHINGTON
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-07-19 至 2015-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7982925
• 关键词: A kinase anchoring protein; Acute; Affect; American; Arteries; Arts; Biological; Blood Pressure; Blood Vessels; Calcium; Cardiovascular system; Cells; Contractile Proteins; Cyclic AMP-Dependent Protein Kinases; Data; Development; Diabetes Mellitus; Dihydropyridines; Disease; Electrophysiology (science); Event; Figs - dietary; Functional disorder; Gene Expression; Goals; Hyperglycemia; Hypertension; Image; L-Type Calcium Channels; Membrane; Metabolic; Modality; Modeling; Molecular; Molecular Models; Morbidity - disease rate; Muscle; Muscle Cells; Non-Insulin-Dependent Diabetes Mellitus; Optics; Outcome; Pathway interactions; Phosphotransferases; Physiological; Play; Potassium; Potassium Channel; Regulation; Reporting; Research Project Grants; Resistance; Role; Scaffolding Protein; Series; Signal Transduction; Site; Smooth Muscle; Stroke; System; Techniques; Telemetry; Testing; Vascular Smooth Muscle; Work; base; constriction; diabetic; dihydropyridine; innovation; model development; molecular imaging; molecular modeling; mortality; novel; public health relevance; research study; transcription factor; transcription factor NF-AT c3; voltage

DESCRIPTION (provided by applicant): Calcium influx via dihydropyridine-sensitive, voltage-gated L-type calcium channels (LTCC) plays a crucial role in the regulation of excitability, contraction, and gene expression in arterial smooth muscle. Exaggerated Ca2+ influx through smooth muscle LTCCs has been implicated in the chain of events contributing to hyperglycemia- induced vascular dysfunction during non-insulin dependent diabetes mellitus (NIDDM). However, the molecular mechanisms underlying the increase in LTCC activity during hyperglycemia and NIDDM remain poorly defined. Recently, we identified and characterized a novel modality of LTCC function in which a single or a small cluster of these channels can operate in a persistent gating mode that create sites of nearly continual Ca2+ influx (called "persistent Ca2+ sparklets") in arterial myocytes. Under physiological conditions, persistent Ca2+ sparklet activity is low. However, preliminary data presented in this application suggest that Ca2+ sparklet activity increases during hyperglycemia and NIDDM through a mechanism requiring protein kinase A (PKA) activation and membrane targeting of this kinase by the scaffolding protein AKAP150. The goal of this application is to test the central hypothesis that an increase in persistent Ca2+ sparklet activity is an early, critical event in the pathway leading to vascular dysfunction during diabetes. The central hypothesis has been formulated on the basis of strong preliminary data and will be tested by pursuing three novel specific aims. Aim 1 will investigate the mechanisms and functional consequences of increased Ca2+ sparklet activity in arterial smooth muscle during hyperglycemia and diabetes. Aim 2 will determine the role of AKAP150 and PKA activity in the mechanisms leading to increase Ca2+ sparklet activity during acute hyperglycemia and diabetes. Aim 3 will test the hypothesis that persistent Ca2+ sparklets downregulate K+ channel expression through the activation of NFATc3 during acute hyperglycemia and diabetes. These hypotheses will be tested using a series of novel imaging approaches developed by our team in combination with state-of-the-art electrophysiological, cellular, and molecular biological approaches. The proposed work is innovative as it aims to integrate, at multiple levels, the mechanisms contributing to vascular dysfunction during NIDDM. Such outcomes will be significant because they will provide new fundamental information on the mechanisms by which increased Ca2+ sparklet activity underlie vascular dysfunction during NIDDM and may contribute to the development of rational therapies for the treatment of this pathological condition. PUBLIC HEALTH RELEVANCE: Approximately 10 million Americans suffer of non-insulin dependent diabetes, which, if untreated, leads to several cardiovascular complications such as hypertension and strokes. This research project will determine the mechanisms by which hyperglycemia induces the activation of a novel Ca2+ signaling modality (e.g. persistent Ca2+ sparklets) in the muscle cells of blood vessels, causing increased contraction and thereby leading to arterial dysfunction during diabetes.

描述（由申请人提供）：通过二氢吡啶敏感，电源门控L型钙通道（LTCC）通过二氢吡啶敏感的钙流入在动脉平滑肌中的兴奋性，收缩和基因表达中起着至关重要的作用。通过平滑肌LTCCs夸大的Ca2+流入与在非胰岛素依赖性糖尿病（NIDDM）期间导致高血糖诱导的血管功能障碍的事件有关。但是，高血糖和NIDDM期间LTCC活性增加的基础机制仍然很差。最近，我们确定并表征了LTCC函数的新型方式，其中这些通道的一个或一小部分可以在持久的门控模式下运行，该模式在动脉肌细胞中创建几乎连续的Ca2+涌入位点（称为“持续的Ca2+ Sparklets”）。在生理条件下，持续的Ca2+火花活动较低。然而，本应用程序中介绍的初步数据表明，在高血糖和NIDDM期间，Ca2+ Sparplet活性通过需要蛋白激酶A（PKA）激活和膜靶向这种激酶的机制增加了脚手架蛋白AKAP150。该应用的目的是测试中心假设，即持续的Ca2+ Sparklet活动的增加是导致糖尿病期间血管功能障碍的途径的早期，关键事件。中心假设是根据强大的初步数据提出的，将通过追求三个新颖的特定目标来测试。 AIM 1将研究高血糖和糖尿病期间动脉平滑肌中Ca2+火花活动增加的机制和功能后果。 AIM 2将确定AKAP150和PKA活性在导致急性高血糖和糖尿病期间Ca2+ Sparklet活性的机制中的作用。 AIM 3将检验以下假设：持续的Ca2+火花通过在急性高血糖和糖尿病期间激活NFATC3的K+通道表达。这些假设将通过我们的团队与最先进的电生理，细胞和分子生物学方法相结合的一系列新型成像方法进行检验。拟议的工作具有创新性，因为它旨在以多个级别整合导致NIDDM期间血管功能障碍的机制。这些结果将是重要的，因为它们将提供有关NIDDM期间血管功能障碍的CA2+ Sparklet活性增加的机制的新基本信息，并可能有助于开发理性疗法以治疗这种病理状况。 公共卫生相关性：大约1000万美国人患有非胰岛素依赖性糖尿病，如果未经治疗，会导致几种心血管并发症，例如高血压和中风。该研究项目将确定高血糖诱导血管肌肉细胞中新型Ca2+信号传导方式（例如持续的Ca2+ Sparplets）激活的机制，从而导致收缩增加，从而导致糖尿病期间动脉功能障碍。