The Impact of Hemoglobin S on Red Blood Cell Nitric Oxide Production

血红蛋白 S 对红细胞一氧化氮生成的影响

• 批准号: 9376631
• 负责人: Jon A Detterich
• 金额: $ 8.33万
• 依托单位: CHILDREN'S HOSPITAL OF LOS ANGELES
• 依托单位国家: 美国
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-08-11 至 2019-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9376631
• 关键词: Acute; Adhesions; Affect; Alpha Cell; American; Arteries; Basal Cell; Bioavailable; Biochemical; Biological Availability; Biological Models; Biophysics; Blood; Blood Vessels; California; Cells; Centers for Disease Control and Prevention (U.S.); Child; Chronic; Clinical Research; Complex; Data Collection; Diffuse; Disease; Dissociation; Enzymes; Erythrocytes; Functional disorder; Gene Mutation; Generations; Genes; Goals; Grant; Health; Heart; Heme; Hemoglobin; Hemoglobin concentration result; Hemolysis; Hospitalization; Human; Hypoxia; Inclusion Bodies; Insurance Carriers; Iron; Kidney Diseases; Laboratories; Left; Link; Mechanical Stress; Mechanics; Mediating; Mediator of activation protein; Medicaid; Mentored Patient-Oriented Research Career Development Award; Metabolic; Methods; Modeling; Morbidity - disease rate; N,N-dimethylarginine; NOS3 gene; Nitric Oxide; Nitrites; Oxygen; Pain; Patients; Phenotype; Plasma; Platelet aggregation; Play; Polymers; Predisposition; Priapism; Privatization; Process; Production; Pulmonary Hypertension; Pulmonary artery structure; Regulation; Research Proposals; Research Training; Role; Rupture; Sickle Cell; Sickle Cell Anemia; Sickle Hemoglobin; Skin Ulcer; Source; Stroke; United States; Variant; Vascular Diseases; Vascular remodeling; Work; acute chest syndrome; arginase; base; beta Globin; career development; cost; design; improved; inhibitor/antagonist; mortality; multimodality; new therapeutic target; novel; oxidative damage; patient oriented research; polymerization; pressure; shear stress; sickling; statistics; stem; therapeutic target; tissue oxygenation; translational study; vascular bed; vascular inflammation; vasoconstriction

Project Summary Sickle cell disease is a progressive vasculopathy stemming from decreased red blood cell (RBC) deformability. Vascular disease is at the heart of both acute and chronic sickle disease, including pain crisis, acute chest syndrome, stroke, skin ulcers, and pulmonary hypertension. However, the mechanisms linking decreased RBC deformability to chronic vasculopathy are multifactorial and poorly characterized. Nitric oxide (NO) is the key mediator linking blood mechanics to vessel tone and vascular remodeling. NO bioavailability is diminished in SCD because decellularized hemoglobin and arginase, released during hemolysis, scavenge NO and lower endothelial NO production. Recent evidence suggests that 50% of bioavailable NO is synthesized within RBC, themselves, through a shear-activated eNOS enzyme. RBC NO is primarily converted to nitrite and nitrosylated hemoglobins when tissue oxygenation is high, but deoxygenated hemoglobin converts these species to nitric oxide under hypoxic conditions. Thus, RBC generated NO appears to be a vital mediator of oxygen supply and demand and its role in sickle cell vasculopathy is unexplored. Early results from our lab suggest that tissue oxygenation is dependent on RBC deformability at high shear. Deformation of healthy and SCD RBC increases NO production to a similar degree, while basal NO production is higher in SCD RBC. With the addition of nitrite to fully oxygenated SCD RBC basal production of NO is increased whereas it did not change in healthy RBC. Our overall goal is to demonstrate that nitrite and NOS contribute to RBC NO production, which in turn plays a significant role in the vascular health of normal healthy subjects and patients with sickle cell disease, a human model of diffuse vasculopathy. This research proposal leverages our current work in sickle cell disease vascular function assessment and novel laboratory methods in RBC nitric oxide production. Multimodal characterization of the different vascular beds will lead to improved phenotypic categorization and pathophysiological links to the underlying RBC biophysical/biochemical derangements. We continue to explore whether RBC-generated NO has the ability to decreases platelet aggregation. The studies proposed in Aim I and II will separate the effect of basal and shear-mediated NO production allowing us to determine control mechanisms in healthy and SCD patients. We know that a paradox exists whereby tissue oxygenation is low in non-transfused SCD subjects, while microcirculatory flow is increased. This may be due to changes in nitric oxide production due to nitrite reduction from hemoglobin S deoxygenation, shear-mediated changes in NO production or both. Our overall design, which performs Aims I/II simultaneously with studies in Aim III, should resolve this paradox. The K23 mechanism represents the natural extension my career development to date, combining my previous laboratory and patient-oriented research expertise with the specific clinical research training necessary to conduct large translational studies of novel targets in vascular dysfunction.

项目摘要 镰状细胞病是一种进行性血管病变，源于红细胞（RBC）变形能力下降。 血管疾病是急性和慢性镰状病的核心，包括疼痛危象、急性胸 综合征、中风、皮肤溃疡和肺动脉高压。但连接机制减少， 红细胞变形性对慢性血管病变是多因素的，特点不明确。一氧化氮（NO）是 将血液力学与血管张力和血管重塑联系起来的关键介质。NO生物利用度降低 在SCD中，由于溶血过程中释放的脱细胞血红蛋白和凝血酶， 内皮NO生成。最近的证据表明，50%的生物可利用的NO在RBC内合成， 通过剪切激活的eNOS酶。RBC NO主要转化为亚硝酸盐， 当组织氧合高时，亚硝基化血红蛋白，但脱氧血红蛋白将这些 一氧化氮在缺氧条件下。因此，红细胞产生的NO似乎是一个重要的调解人， 氧的供应和需求及其在镰状细胞血管病变中的作用尚未被探索。我们实验室的初步结果 表明组织氧合依赖于红细胞在高剪切力下变形能力。变形的健康和 SCD RBC以类似程度增加NO产生，而基础NO产生在SCD RBC中更高。与 向完全氧合的SCD RBC中加入亚硝酸盐增加了NO的基础产生，而没有 健康RBC的变化。我们的总体目标是证明亚硝酸盐和NOS有助于RBC NO 产生，这反过来又在正常健康受试者的血管健康中起重要作用， 镰状细胞病患者，一种弥漫性血管病变的人类模型。本研究提案 利用我们目前在镰状细胞病血管功能评估方面的工作和新的实验室方法， RBC一氧化氮生成。不同血管床的多模态表征将导致改善的 表型分类和与基础RBC生物物理/生化的病理生理学联系 混乱我们将继续探索红细胞产生的NO是否具有降低血小板聚集的能力。 聚合来目的I和II中提出的研究将分离基础和剪切介导的NO的作用。 生产使我们能够确定健康和SCD患者的控制机制。我们知道一个 存在悖论，即非输血SCD受试者的组织氧合较低，而微循环流量 提高了这可能是由于血红蛋白S减少亚硝酸盐导致一氧化氮产生的变化 脱氧、剪切介导的NO产生变化或两者。我们的整体设计， 第一/第二部分与目标三的研究同时进行，应能解决这一矛盾。K23机制代表了 自然延伸我的职业发展至今，结合我以前的实验室和病人为导向 具有进行大型转化研究所需的特定临床研究培训的研究专业知识， 血管功能障碍的新靶点。