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

基本信息

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
项目类别：
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

项目摘要

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 (2E26K) 是世界范围内最常见的天然存在的 Hb 突变体，在 1121 界面处有突变。 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神秘的。由于 HbE 已被证明具有正常的氧亲和力（Bunn 等人，1972），因此我们提出了一种可能的机制，即 HbE 可能会降低产生足够的生物活性一氧化氮 (NO) (1) 的能力，从而提供针对高水平的保护2-地中海贫血引起的膜损伤活性氧 (ROS) 和 (2) 作为内皮功能的次要 NO 来源。为了支持这一假设，我们从 HbE 获得了初步数据，显示与 HbA 相比，亚硝酸还原酶活性降低。我们小组最近获得了高分辨率脱氧和配体的 HbE 结构（蛋白质数据库条目 1YVQ、1YVT、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。拟议的项目以这两项发现为基础，旨在确定亚硝酸盐反应性改变的程度和分子起源。该项目将利用创新的溶胶-凝胶封装方案来捕获和表征 HbE 的 T 和 R 状态的反应性，涉及一系列旨在促进生物活性 NO 产生的反应。该项目旨在确定 HbE 的来源改变了从亚硝酸盐生成生物活性一氧化氮的反应性是否源于变构、局部三级结构或 T 和 R 态氧化还原特性的变化。这些研究具有重要意义，因为它们可能为 HbE 衍生的病理生理学起源提供一种新的机制，并对其他与内皮功能障碍相关的 Hb 相关病理和疾病产生影响。有可能建立一种新的范例来开发 HbE 2-地中海贫血的治疗方法。公共健康相关性：本提案旨在了解引起血红蛋白 E 疾病的根本原因，其中一种疾病可导致身体和精神发育迟缓，并可导致死亡（通常是由于心脏功能障碍）。本提案的目的是检验以下假设：该疾病源于 HbE 的特性，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。