Mechanisms of platelet stimulation in hemolysis

溶血中血小板刺激的机制

• 批准号: 10370496
• 负责人: Deirdre Nolfi-Donegan
• 金额: $ 12.82万
• 依托单位: UNIVERSITY OF PITTSBURGH AT PITTSBURGH
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-02-15 至 2027-01-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10370496
• 关键词: Advisory Committees; Attenuated; Blood; Blood Platelet Disorders; Blood Platelets; Blood Vessels; Cells; Complex; Cysteine; Data; Development; Development Plans; Disease; Disulfides; Electron Transport; Environment; Erythrocytes; Event; Experimental Models; Foundations; Generations; Genetic Diseases; HMGB1 Protein; Haptoglobins; Heme; Hemoglobin; Hemolysis; Hemopexin; Human; Hypoxia; Incubated; Inflammation; Inflammation Mediators; Inflammatory; Infusion procedures; Institute of Medicine (U.S.); Knock-out; Life; Link; Mass Spectrum Analysis; Measurement; Measures; Mediating; Membrane Potentials; Mentors; Mentorship; Mitochondria; Molecular; Mus; Oxidation-Reduction; Oxides; Pathogenesis; Pathway interactions; Patients; Pattern; Plasma; Platelet Activation; Platelet aggregation; Play; Polymers; Production; Proteins; Pulmonary Hypertension; Reactive Oxygen Species; Receptor Signaling; Recombinants; Research; Research Personnel; Respiration; Risk; Role; Sickle Cell Anemia; Sickle Hemoglobin; Signal Pathway; Signal Transduction; Sterility; Stimulant; Stimulus; Stroke; Sulfhydryl Compounds; Surface; TLR4 gene; Therapeutic; Thrombosis; Thrombus; Training; Transgenic Mice; Universities; Work; base; career; career development; ferric chloride; hemoglobin polymer; high risk; improved; in vivo; inhibitor; mouse model; multidisciplinary; mutant; new therapeutic target; novel; oxidation; prevent; receptor; synergism; therapeutic target; thrombotic; thrombotic complications

ABSTRACT While sickle cell disease (SCD) is instigated by a mutant hemoglobin that polymerizes in hypoxia to cause hemolysis and vaso-occlusion, inflammation plays a fundamental role in propagating this pathogenesis. SCD patients are at significantly higher risk of thrombosis, which contributes to severe life-threatening complications such as pulmonary hypertension and stroke. On a cellular level, it is well established that in SCD patients, platelet activation is elevated and correlates with hemolysis. However, the contribution of inflammatory signaling to platelet activation and its cross-talk with hemolysis remain unknown. High-mobility group box 1 (HMGB1), an inflammatory mediator released by cells, has been shown to be elevated in the blood of SCD patients and to stimulate platelet activation. Notably, the ability of HMGB1 to mediate platelet activation is dependent on the oxidation state of critical cysteine residues in the protein. Preliminary data shows that HMGB1-mediated platelet activation is significantly enhanced in the presence of cell-free hemoglobin (Hb), a major component of hemolysis. Further, Hb and HMGB1 each independently increase platelet mitochondrial reactive oxygen species (mtROS) generation, a known stimulus for platelet activation. Based on these data, I hypothesize that in SCD, Hb oxidizes HMGB1 to increase platelet mtROS production leading to platelet activation and secondary release of additional thrombotic stimulants including HMGB1 from platelets. Aim 1 will determine whether Hb oxidizes HMGB1 to potentiate its activation of platelets using human healthy and sickle Hb and platelets in ex vivo experimental models. Aim 2 will determine the mechanism by which HMGB1-induced mtROS stimulates platelet activation. Aim 3 will utilize murine models of hemolysis to determine whether neutralizing HMGB1 attenuates platelet activation and thrombus formation. Successful completion of these aims will elucidate a novel mechanism of synergy between hemolysis and inflammatory signaling in potentiating thrombosis. This work will reveal novel therapeutic targets and potential therapeutics for the treatment of thrombosis in SCD. In addition, this project, along with the guidance of my multi-disciplinary mentorship team, career development plan, and cutting-edge research environment at the Vascular Medicine Institute at the University of Pittsburgh, will serve as a strong training vehicle to facilitate my independence as a researcher focused on mechanisms of thrombosis in hemolytic disease.

抽象的 镰状细胞疾病（SCD）是由突变血红蛋白促进了缺氧的聚合物的突变体血红蛋白 溶血和血管结合，炎症在传播这种发病机理中起着基本作用。 scd 患者的血栓形成风险明显更高，这导致严重威胁生命的并发症 例如肺动脉高压和中风。在细胞水平上，可以很好地确定在SCD患者中，血小板 激活升高并与溶血相关。但是，炎症信号传导对 血小板激活及其与溶血的串扰仍然未知。高机动性组框1（HMGB1），一个 细胞释放的炎症介质已显示在SCD患者的血液中升高 刺激血小板激活。值得注意的是，HMGB1介导血小板激活的能力取决于 蛋白质中关键半胱氨酸残基的氧化态。初步数据显示HMGB1介导的血小板 在存在无细胞血红蛋白（Hb）的情况下，激活显着增强，这是 溶血。此外，HB和HMGB1各自独立增加血小板线粒体活性氧 （MTROS）生成，一种已知的血小板激活刺激。基于这些数据，我假设在SCD中， HB氧化HMGB1以增加血小板MTROS的产生，导致血小板激活和次级释放 其他血小板刺激剂，包括血小板的HMGB1。 AIM 1将确定HB是否氧化 HMGB1使用人类健康和镰状HB和小血小板增强其血小板的激活 实验模型。 AIM 2将确定HMGB1诱导的MTRO刺激血小板的机制 激活。 AIM 3将利用溶血的鼠模型来确定中和HMGB1是否会减弱 血小板激活和血栓形成。这些目标的成功完成将阐明一本小说 溶血和炎症信号之间的协同作用在增强血栓形成中。这项工作将 揭示了用于治疗SCD血栓形成的新型治疗靶标和潜在的治疗剂。此外， 这个项目，以及我的跨学科指导团队，职业发展计划和 匹兹堡大学血管医学研究所的尖端研究环境将服务 作为强大的训练工具，可以促进我作为研究人员的独立性，专注于血栓形成机制 在溶血疾病中。