Exploring the mechanisms of action of anti-ADAMTS 13 antibodies in immune thrombotic thrombocytopenic purpura

探讨抗 ADAMTS 13 抗体在免疫性血栓性血小板减少性紫癜中的作用机制

• 批准号: 10429277
• 负责人: Konstantine Halkidis
• 金额: $ 16.52万
• 依托单位: UNIVERSITY OF KANSAS MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-08-18 至 2027-07-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10429277
• 关键词: Address; Advisory Committees; Affect; Affinity; Agglutination; Agreement; Antibodies; Area; Autoantibodies; Autoimmune; Binding; Binding Sites; Biological Assay; Blood Platelets; Clinic; Clinical; Clinical Management; Coupled; Data; Deuterium; Development Plans; Diagnostic; Diagnostic tests; Disease; Disease Management; Disintegrins; Distal; Endothelium; Enzyme Inhibition; Enzymes; Epitopes; Functional disorder; Goals; Hematologic Neoplasms; Hematological Disease; Human; Hydrogen; IgG autoantibodies; Immune; Immunodiagnostics; Immunoglobulin G; Immunotherapy; Individual; Informal Social Control; Internal Medicine; Kansas; Life; Mass Spectrum Analysis; Mediating; Medical center; Mentors; Metalloproteases; Molecular; Molecular Conformation; Monoclonal Antibodies; Morbidity - disease rate; Non-Malignant; Organ; Outcome; Pathogenesis; Patients; Phage Display; Physicians; Physiological; Plasma; Plasmapheresis; Process; Prognosis; Recurrent disease; Research; Research Personnel; Research Training; Role; Scientist; Site; Source; Specificity; Structure; Techniques; Temperature; Tertiary Protein Structure; Testing; Therapeutic; Therapeutic Agents; Therapeutic Intervention; Thrombosis; Thrombospondins; Thrombotic Thrombocytopenic Purpura; Time; Training; Translating; Universities; Work; career; career development; cleavage factor; disorder risk; enzyme activity; human monoclonal antibodies; improved; in vitro activity; in vivo; in-vitro diagnostics; inhibiting antibody; inhibitor; insight; meetings; mortality; novel diagnostics; novel strategies; novel therapeutic intervention; prevent; professor; structural biology; tenure track; thrombotic; von Willebrand Factor

Project Summary/Abstract Immune thrombotic thrombocytopenic purpura (iTTP) is a thrombotic microangiopathy caused by autoimmune inhibition of the enzyme ADAMTS13. The only known substrate of ADAMTS13 is von Willebrand factor (VWF). Cleavage of VWF by ADAMTS13 is needed to prevent accumulation of ultralarge VWF multimers in the microvasculature, leading to end-organ damage and potentially life-threatening consequences. Anti-ADAMTS13 IgGs are responsible for the inhibition of the enzyme. The vast majority of inhibitory antibodies target a region of ADAMTS13 that is principally responsible for binding to the domain of VWF cleaved by the enzyme. However, the mechanism of inhibition of these antibodies is currently an area of active research, and it is not known if they primarily prevent substrate binding or decrease catalytic turnover, or if different antibodies inhibit by different mechanisms. Recent work has shown that ADAMTS13 in iTTP patient plasma exists primarily in a conformation that exposes a cryptic epitope otherwise hidden when ADAMTS13 is in its latent state. The current paradigm of ADAMTS13 activity defines this as a so-called “Open” state, and the latent state as “Closed”. A third state also appears to exist in which ADAMTS13 has the cryptic episode exposed, but also is able to cleave VWF; this is referred to here as the “Open and Primed” state. Anti-ADAMTS13 IgGs that target distal domains of the protein appear capable of inducing both the “Open” and “Open and Primed” state. The role of the different conformations of ADAMTS13 in the pathophysiology of iTTP is unclear, as is the potential role of the distal domain-targeting IgGs in the disease. Lastly, it is not known if ADAMTS13 activity can be rescued by introducing moieties capable of competing for the binding of anti-ADAMTS13 IgGs with ADAMTS13. This project aims to elucidate the mechanism(s) of inhibition of anti-ADAMTS13 antibodies, characterize the role of distal domain-targeting anti- ADAMTS13 antibodies in the pathophysiology of the disease, and explore molecular mimics of the binding epitopes of anti-ADAMTS13 IgGs as a rescue strategy for the disease. My career goal is to become an independent investigator as a physician scientist, with a focus on the pathophysiology of iTTP. I am currently on the tenure-track as an Assistant Professor in the Department of Internal Medicine, Division of Hematologic Malignancies and Cellular Therapeutics, at the University of Kansas Medical Center (KUMC), a large academic center. My research mentor is Dr. X. Long Zheng, a world-renowned researcher in iTTP. I am afforded 80% protected time for research under my agreement with the University. My career development plan includes regular meetings with my Career Advisory Committee, hands-on training in the structural biology techniques included in this proposal, and ongoing clinical responsibilities, including a half-day of clinic weekly where I see patients with non-malignant hematologic disorders.

项目概要/摘要 免疫性血栓性血小板减少性紫癜（iTTP）是一种由自身免疫性疾病引起的血栓性微血管病 ADAMTS13 酶的抑制 ADAMTS13 唯一已知的底物是血管性血友病因子 (VWF)。 需要通过 ADAMTS13 切割 VWF，以防止超大型 VWF 多聚体在 微血管，导致终末器官损伤和潜在的危及生命的后果。 IgG 负责抑制该酶，绝大多数抑制性抗体都针对某个区域。 ADAMTS13 主要负责与被酶切割的 VWF 结构域结合。 这些抗体的抑制机制目前是一个活跃的研究领域，尚不清楚它们是否 主要阻止底物结合或减少催化周转，或者如果不同的抗体通过不同的抑制 最近的研究表明，iTTP 患者血浆中的 ADAMTS13 主要以一种构象存在。 当 ADAMTS13 处于潜在状态时，它会暴露一个隐藏的表位。 ADAMTS13 活动将其定义为所谓的“打开”状态，并将潜在状态定义为“关闭”第三种状态。 似乎存在 ADAMTS13 暴露了神秘事件，但也能够裂解 VWF； 此处称为“开放和引发”状态，靶向蛋白质的远端结构域。 似乎能够诱导“开放”和“开放和启动”状态不同构象的作用。 ADAMTS13 在 iTTP 病理生理学中的作用尚不清楚，远端结构域靶向的潜在作用也不清楚 最后，尚不清楚 ADAMTS13 活性是否可以通过引入具有功能的部分来恢复。 该项目旨在阐明抗 ADAMTS13 IgG 与 ADAMTS13 的结合竞争。 抑制抗 ADAMTS13 抗体的机制，表征远端域靶向抗-ADAMTS13 抗体的作用 ADAMTS13 抗体在疾病病理生理学中的作用，并探索结合的分子模拟物 抗 ADAMTS13 IgG 表位作为疾病的救援策略 我的职业目标是成为一名医生。 作为一名医学科学家的独立研究者，我目前主要研究 iTTP 的病理生理学。 内科血液科助理教授的终身职位 大型学术机构堪萨斯大学医学中心 (KUMC) 的恶性肿瘤和细胞治疗 我的研究导师是X. Long Cheng博士，他是iTTP领域的世界著名研究员，我的学费是80%。 根据我与大学的协议，我的职业发展计划包括受保护的研究时间。 与我的职业咨询委员会定期举行会议，进行结构生物学技术的实践培训 包括在这个提案中，以及持续的临床责任，包括每周半天的诊所，我在那里看到 患有非恶性血液系统疾病的患者。