Role of Endothelin System and NAD(P)H Oxidase in Retinal Arteriolar Dysfunction

内皮素系统和 NAD(P)H 氧化酶在视网膜小动脉功能障碍中的作用

基本信息

批准号：
7926513
负责人：
TRAVIS W HEIN
金额：
$ 29.35万
依托单位：
SCOTT AND WHITE MEMORIAL HOSPITAL
依托单位国家：
美国
项目类别：
财政年份：
2008
资助国家：
美国
起止时间：
2008-01-01 至 2009-12-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7926513
关键词：
Acetylcholine Acute Address Affect Agonist Angle-Closure Glaucoma Animal Welfare Bibliography Biological Availability Blindness Blood Vessels Blood flow Bradykinin Brain Country Diabetic Retinopathy Disease Endothelin Endothelin B Receptor Endothelin Receptor Endothelin-1 Endothelin-converting enzyme 1 Endothelium Environment Environmental Impact Enzyme Inhibitor Drugs Enzyme Inhibitors Equipment Event Family suidae Functional disorder Future Goals Heart IACUC Impairment In Vitro International Ischemia Lead Link MAPK14 gene Mediating Mitogen-Activated Protein Kinases Mitogens Modality Modeling Molecular Neurons Nitric Oxide Operative Surgical Procedures Oxidases Oxidative Stress Pathogenesis Pathway interactions Physiologic Intraocular Pressure Physiological Pilot Projects Principal Investigator Production Protein Kinase Protein Kinase C Proteins Reactive Oxygen Species Regulation Relative (related person)Research Research Ethics Committees Resources Retina Retinal Retinal Vascular Occlusion Retinopathy of Prematurity Rho-associated kinase Role Series Signal Pathway Signal Transduction Site Smooth Muscle Source Superoxides System Techniques Testing Therapeutic Intervention Vascular Diseases Vasoconstrictor Agents Vasodilation Vasodilator Agents Vasomotor Vertebrates Visual impairment abstracting arteriole citrate carrier constriction endothelin-converting enzyme expiration human MAPK14 protein human subject in vivo novel phosphoramidon prevent programs receptor research study retinal damage retinal ischemia rho tempol vasoconstriction

项目摘要

Acute periods of retinal ischemia impair subsequent supply of retinal blood flow and have been associated with several ocular diseases leading to visual impairment and blindness. Experimental evidence of diminished retinal blood flow after the initial retinal ischemia suggests that endothelial dysfunction may contribute to persistent retinal damage. Two important endothelium-derived factors involved in regulating retinal blood flow are vasodilator nitric oxide (NO) and vasoconstrictor endothelin-1 (ET-1). Our preliminary studies showed that retinal ischemia via elevated intraocular pressure (IOP) impaired bradykinin-induced NO-mediated dilation and enhanced ET-1-mediated constriction in pig retinal arterioles. Intravitreal administration of superoxide scavenger TEMPOL or endothelin-converting enzyme (ECE) inhibitor phosphoramidon before ischemia preserved vasodilation to bradykinin. Although these pilot studies suggest the involvement of ET-1 and oxidative stress in vascular dysfunction, their interrelationship and the signaling events contributing to the observed impairment remain to be elucidated. Herein, we hypothesize that ischemic insult activates the protein kinase C (PKC)-dependent vascular endothelin system, which leads to superoxide production via NAD(P)H oxidase and a subsequent increase in Rho/Rho kinase activation for the increased vascular tone and a reduced NO-mediated vasodilation. Since our long-term goal is to understand the signaling mechanisms responsible for physiological and pathophysiological regulation of retinal vasomotor function leading to future vascular therapy, the present application will serve the initial step toward this goal by identifying the causal factor and cellular mechanisms contributing to the impairment of vascular function following acute retinal ischemia. We will test the aforementioned hypothesis by pursuing three specific aims: (1) Determine whether enhanced ECE and PKC activities contribute to ischemia-induced dysfunction of retinal arterioles. (2) Determine whether activation of endothelin A/B receptors and vascular p38 mitogen-activated protein kinase/NAD(P)H oxidase signaling contributes to ischemia-induced dysfunction of retinal arterioles. (3) Determine whether enhanced vascular Rho/Rho kinase signaling contributes to ischemia-induced dysfunction of retinal arterioles. We will use both in-vivo and in-vitro approaches with various cellular/molecular techniques to integrate these three aims for elucidating the underlying mechanisms and signaling pathways responsible for the ischemia-induced arteriolar dysfunction in the retina. The results derived from these studies are essential to advance our understanding in the pathogenesis of retinal vascular disease associated with retinal ischemia and may suggest novel targets for future therapeutic interventions.

视网膜缺血的急性周期会损害视网膜血流的供应，并与几种眼部疾病有关，导致视觉障碍和失明。实验证据减少初始视网膜缺血后的视网膜血流表明内皮功能障碍可能有助于持续的视网膜损害。调节视网膜血流的两个重要的内皮衍生因素是血管扩张剂一氧化氮（NO）和血管收缩的内皮素-1（ET-1）。我们的初步研究表明，通过升高的眼内压（IOP）降低了心动过队诱导的无介导的扩张并增强了猪视网膜动脉的ET-1介导的收缩，视网膜缺血受损。玻璃体内给药超氧化物清除型tempol或内皮素转化酶（ECE）抑制剂磷氧化酶之前缺血之前保留了血管舒张的血管舒张。尽管这些初步研究表明ET-1和氧化应激在血管功能障碍中的参与，但它们的相互关系和导致观察到的障碍的信号传导事件仍有待阐明。本文中，我们假设缺血性损伤激活了蛋白激酶C（PKC）依赖性血管内皮素系统，从而导致通过NAD（P）H氧化酶产生超氧化物，随后Rho/Rho激酶激活增加了血管张力和无介导的杂种质量的增加。由于我们的长期目标是了解导致视网膜血管舒缩功能的生理和病理生理调节的信号传导机制，从而导致未来的血管疗法，因此本应用将通过确定导致急性视网膜质量质量性血管内血管功能的因果因素和细胞机制来朝着该目标迈出的初步步骤。我们将通过追求三个具体目标来检验上述假设：（1）确定增强的ECE和PKC活动是否有助于缺血引起的视网膜动脉功能障碍。（2）确定内皮素A/B受体的激活以及血管p38促丝分裂原激活的蛋白激酶/NAD（P）H氧化酶信号传导是否有助于缺血诱导的视网膜动脉功能障碍。（3）确定增强的血管RHO/RHO激酶信号是否有助于缺血引起的视网膜动脉功能障碍。我们将使用各种细胞/分子技术使用体内和体外方法来整合这三个目的，以阐明导致视网膜中缺血诱导的小动脉功能障碍的基本机制和信号传导途径。从这些研究中得出的结果对于促进我们在与视网膜缺血相关的视网膜血管疾病的发病机理中的理解至关重要，并且可能暗示了未来治疗干预措施的新靶标。