Production of Bioactive NO: Origin of Hemoglobin E Associated Pathophysiology

生物活性一氧化氮的产生：血红蛋白 E 的起源相关病理生理学

• 批准号: 8030696
• 负责人: JOEL M FRIEDMAN
• 金额: $ 24.9万
• 依托单位: ALBERT EINSTEIN COLLEGE OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-12-15 至 2012-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8030696
• 关键词: Affinity; Anemia; Biological Availability; Blood Vessels; Cardiac; Cardiovascular Physiology; Cell membrane; Cessation of life; Chronic; Clinical; Coupling; Data; Databases; Disease; Erythrocytes; Evaluation; Exhibits; Functional disorder; Gel; Heart; Heart Diseases; Hemoglobin; Hemoglobin E; Hemoglobin E Disease; Hemoglobinopathies; In Vitro; Individual; Induced Mutation; Lead; Ligands; Light; Link; Mediating; Membrane; Mental Retardation; Modeling; Molecular; Molecular Conformation; Morbidity - disease rate; Mutation; Nitric Oxide; Nitrite Reductase; Nitrites; Outcome; Oxidation-Reduction; Oxidative Stress; Oxygen; Pathologic; Pathology; Patients; Play; Production; Property; Proteins; Protocols documentation; Reaction; Reactive Oxygen Species; Relative (related person); Reporting; Resolution; Role; Series; Sickle Cell Anemia; Source; Structure; Testing; Thalassemia; Therapeutic; X-Ray Crystallography; base; innovation; mutant; novel; programs; protein structure; therapy development

DESCRIPTION (provided by applicant): Hemoglobin (Hb) E (2E26K) is the most common worldwide naturally occurring mutant Hb with a mutation at the 1121 interface. EE individuals exhibit a mild, chronic anemia while HbE/2-thalassemia individuals show a range of clinical manifestations, including high morbidity, and death, often resulting from cardiac dysfunction. The significant role of HbE in the red blood cell pathophysiology and molecular mechanisms giving rise to the HbE diseases is enigmatic. Since, HbE has been shown to have normal oxygen affinity (Bunn et al., 1972), we have proposed a possible mechanism whereby HbE may have reduced capacity to generate sufficient bioactive nitric oxide (NO) (1) to confer protection against high levels of membrane damaging reactive oxygen species (ROS) arising from the 2-thalassemia and (2) as a secondary NO source for endothelial functioning. In support of this hypothesis we have obtained preliminary data from HbE showing decreased nitrite reductase activity compared to HbA. Our group recently obtained the high resolution deoxy and liganded HbE structures (Protein Data Bank entries 1YVQ, 1YVT, 3DUT) and found that the tertiary conformations within the T and R quaternary structures of HbE are altered relative to HbA. The proposed project which builds on these two findings, seeks to establish the extent and molecular origins of the altered nitrite reactivity. The project will utilize innovative sol-gel encapsulation protocols to trap and characterize the reactivity of the T and R state of HbE with respect to a series of reactions proposed to contribute to the production of bioactive NO. The project seeks to determine whether the source of HbE altered reactivity to generate bioactive forms of NO from nitrite arises from changes in allostery, in local tertiary structure or in the redox properties of the T and R states. These studies are of significance in that they are likely to provide a novel mechanism for the origin of HbE-derived pathophysiology with implications for other Hb related pathologies and diseases linked to endothelial dysfunction. There is the potential for a new paradigm in which to develop therapies for HbE 2-thalassemia. PUBLIC HEALTH RELEVANCE: This proposal aims to understand the fundamental causes that give rise to Hemoglobin E diseases, one of which can cause body and mental retardation and can lead to death, usually from heart malfunction. It is the aim of this proposal to test the hypothesis that this disease originates from properties of HbE that reduce its capacity to produce nitric oxide from nitrite. These findings have the potential to change the way doctors view and treat the often fatal HbE/2-thalassemia disease.

描述（由申请人提供）：血红蛋白（Hb）E（2 E26 K）是世界范围内最常见的天然突变型Hb，在1121界面处发生突变。EE个体表现出轻度慢性贫血，而HbE/2-地中海贫血个体表现出一系列临床表现，包括高发病率和死亡，通常由心功能障碍引起。HbE在红细胞病理生理学和引起HbE疾病的分子机制中的重要作用是谜。因为，HbE已显示具有正常的氧亲和力（邦恩et al.，1972），我们已经提出了一种可能的机制，其中HbE可能具有降低的产生足够的生物活性一氧化氮（NO）的能力，（1）以提供针对由β 2-地中海贫血引起的高水平的膜损伤活性氧（ROS）的保护，和（2）作为内皮功能的二级NO来源。为了支持这一假设，我们已经从HbE中获得了初步数据，表明与HbA相比，亚硝酸盐还原酶活性降低。我们的团队最近获得了高分辨率脱氧和配体HbE结构（蛋白质数据库条目1 YVQ，1 YVT，3DUT），并发现HbE的T和R四级结构内的三级构象相对于HbA发生了改变。拟议的项目建立在这两个发现的基础上，旨在建立改变亚硝酸盐反应性的程度和分子起源。该项目将利用创新的溶胶-凝胶包封方案来捕获和表征HbE的T和R状态相对于一系列反应的反应性，这些反应被提议用于产生生物活性NO。该项目旨在确定HbE改变反应性的来源是否来自变构，局部三级结构或T和R状态的氧化还原性质。这些研究具有重要意义，因为它们可能为HbE衍生的病理生理学的起源提供新的机制，并对与内皮功能障碍相关的其他Hb相关病理和疾病产生影响。有可能为HbE 2-地中海贫血开发新的治疗方法。 公共卫生相关性：该提案旨在了解引起血红蛋白E疾病的根本原因，其中一种可能导致身体和智力迟钝，并可能导致死亡，通常是心脏功能障碍。该提案的目的是检验这种疾病起源于HbE的特性的假设，该特性降低了其从亚硝酸盐产生一氧化氮的能力。这些发现有可能改变医生看待和治疗通常致命的HbE/2地中海贫血疾病的方式。