TRP channels in regulation of vascular tone

TRP 通道调节血管张力

• 批准号: 8220836
• 负责人: David X. Zhang
• 金额: $ 38.31万
• 依托单位: MEDICAL COLLEGE OF WISCONSIN
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-02-04 至 2016-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8220836
• 关键词: Acids; Affect; Animals; Applications Grants; Arachidonic Acids; Blood Vessels; Blood flow; Calcium Channel; Cardiovascular Diseases; Cations; Caveolae; Cell membrane; Cell surface; Coronary; Coronary Arteriosclerosis; Coupling; Data; Dilator; Disease; Down-Regulation; Electron Transport; Electrons; Electrophysiology (science); Endoplasmic Reticulum; Endothelial Cells; Endothelium; Event; Fluorescence; Generations; Genetically Engineered Mouse; Goals; Health; Human; Hydrogen Peroxide; Imaging Techniques; In Vitro; Lead; Link; Mechanics; Mediating; Membrane; Microcirculation; Mitochondria; Molecular Biology; Mus; Muscle Cells; Nitric Oxide; Nitric Oxide Donors; Nitric Oxide Synthase; Outcome; Patients; Phospholipase A2; Physiological; Process; Production; Reactive Oxygen Species; Regional Blood Flow; Regulation; Research; Role; Signal Transduction; Site; Small Interfering RNA; Smooth Muscle; Testing; Time; Tissues; Vanilloid; Vascular Endothelial Cell; Vasodilation; Vasodilator Agents; arteriole; caveolin 1; design; human data; inhibitor/antagonist; innovation; knock-down; mouse model; new therapeutic target; novel; public health relevance; receptor; relaxing factor; response; shear stress; vascular bed

DESCRIPTION (provided by applicant): Shear stress generated by blood flow is one of the most important physiological regulators of vascular tone. Flow stimulates vascular endothelial cell to release vasodilator factors that subsequently relax underlying smooth muscle, a response often known as flow-mediated dilation (FMD). In human coronary arterioles (HCA), FMD results from the release of two entirely independent dilator factors: nitric oxide (NO) in subjects without coronary artery disease (CAD), and reactive oxygen species (ROS), specifically hydrogen peroxide (H2O2) derived from the mitochondrial electron transport chain, in CAD patients. However, it remains unsolved how shear induces the release of these two distinct relaxing factors. The present proposal will test a central hypothesis that the transient receptor potential vanilloid 4 (TRPV4) channel serves as a common mechanism for the release of two otherwise diversely regulated relaxing factors (NO and mitochondria-derived H2O2) responsible for FMD in the human coronary microcirculation. We further propose that the signaling cascade occurs within caveolae that host novel interactions between the plasma membrane and mitochondria. Studies will be conducted on isolated HCA and cultured endothelial cells using an integrated approach incorporating molecular biology, electrophysiology and fluorescence/electron imaging techniques with in vitro assessment of vessel reactivity. Genetically engineered mice will also be used to provide more definitive corroboration of the human data. Three specific aims are proposed. Aim 1 will determine whether FMD requires endothelial TRPV4 in HCA from patients with or without CAD. We will test the effects of pharmacological inhibition and siRNA downregulation of TRPV4 on flow-induced Ca2+ entry, ROS/NO release, and vasodilation in HCA from CAD and non-CAD subjects. In aim 2, we will examine whether endothelial TRPV4 channels are associated with caveolae and whether this association is essential for shear-induced TRPV4 activation. We will test three caveolae-associated signaling events contributing to TRPV4 activation: namely, TRPV4 translocation, caveolin-1 regulation, and phospholipase A2-epoxyeicosatrienoic acids activation. In aim 3, we will determine whether shear increases mitochondrial ROS through localized Ca2+ signaling involving caveolar TRPV4 and adjacent mitochondria and whether this process is negatively regulated by NO. The proposed research will, for the first time, link endothelial TRPV4, caveolae, and mitochondria as essential signaling components for FMD in humans. We expect the outcomes of this proposal will substantially increase our understanding of the intricate signaling mechanisms involved in FMD in the human coronary microcirculation, and may lead to new therapeutic targets for the treatment of CAD and/or other cardiovascular disorders. PUBLIC HEALTH RELEVANCE: This grant proposal is designed to study a novel signaling mechanism by which shear stress, a mechanical force generated by blood flow, causes blood vessel dilation in humans. Specifically we examine whether a calcium ion channel (TRPV4) located on the cell surface membrane of vascular endothelial cells serves an essential signaling component for shear-induced dilation in human coronary microvessels. Flow or shear- induced dilation is one of the most important regulators of vascular tone and regional blood flow. Therefore the findings of this proposal will importantly contribute to our understanding of how coronary blood flow is regulated in normal and disease states, and may lead to new therapeutic targets for the treatment of coronary artery disease and/or other cardiovascular disorders.

描述（由申请人提供）：血流产生的剪切应力是血管张力最重要的生理调节因子之一。血流刺激血管内皮细胞释放血管舒张因子，随后放松底层平滑肌，这种反应通常称为血流介导的扩张（FMD）。在人类冠状动脉 (HCA) 中，FMD 是由两种完全独立的扩张因子释放引起的：没有冠状动脉疾病 (CAD) 的受试者中的一氧化氮 (NO) 和 CAD 患者中的活性氧 (ROS)，特别是源自线粒体电子传递链的过氧化氢 (H2O2)。然而，剪切如何诱导这两种不同的松弛因子的释放仍然悬而未决。本提案将测试一个中心假设，即瞬态受体电位香草酸 4 (TRPV4) 通道是释放两种不同调节的松弛因子（NO 和线粒体衍生的 H2O2）的共同机制，这些因子负责人类冠状动脉微循环中的 FMD。我们进一步提出，信号级联发生在细胞膜穴内，细胞膜和线粒体之间存在新的相互作用。将使用结合分子生物学、电生理学和荧光/电子成像技术以及血管反应性体外评估的综合方法对分离的 HCA 和培养的内皮细胞进行研究。基因工程小鼠还将用于为人类数据提供更明确的佐证。提出了三个具体目标。目标 1 将确定 FMD 是否需要患有或不患有 CAD 患者的 HCA 中的内皮 TRPV4。我们将测试 TRPV4 的药物抑制和 siRNA 下调对 CAD 和非 CAD 受试者 HCA 中血流诱导的 Ca2+ 进入、ROS/NO 释放和血管舒张的影响。在目标 2 中，我们将检查内皮 TRPV4 通道是否与小窝相关，以及这种关联是否对于剪切诱导的 TRPV4 激活至关重要。我们将测试导致 TRPV4 激活的三个与小凹相关的信号事件：即 TRPV4 易位、小凹蛋白-1 调节和磷脂酶 A2-环氧二十碳三烯酸激活。在目标 3 中，我们将确定剪切是否通过涉及穴居 TRPV4 和邻近线粒体的局部 Ca2+ 信号传导增加线粒体 ROS，以及该过程是否受到 NO 的负向调节。拟议的研究将首次将内皮 TRPV4、小窝和线粒体作为人类 FMD 的重要信号成分联系起来。我们预计该提案的结果将大大增加我们对人类冠状动脉微循环中 FMD 所涉及的复杂信号机制的理解，并可能为治疗 CAD 和/或其他心血管疾病带来新的治疗靶点。 公共健康相关性：该拨款提案旨在研究一种新颖的信号传导机制，通过该机制剪切应力（一种由血流产生的机械力）引起人体血管扩张。具体来说，我们检查了位于血管内皮细胞细胞表面膜上的钙离子通道（TRPV4）是否是人冠状微血管剪切诱导扩张的重要信号成分。流动或剪切引起的扩张是血管张力和局部血流最重要的调节剂之一。因此，该提案的研究结果将重要地有助于我们了解正常和疾病状态下冠状动脉血流如何调节，并可能导致治疗冠状动脉疾病和/或其他心血管疾病的新治疗靶点。