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: 10685963
• 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/10685963
• 关键词: Advisory Committees; Affect; Affinity; Agglutination; Agreement; Antibodies; Area; Autoantibodies; Autoimmune; Binding; Binding Sites; Biological Assay; Blood Platelets; Blood Vessels; Cell Therapy; 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-Neoplastic Hematologic and Lymphocytic Disorder; Organ; Outcome; Pathogenesis; Patients; Phage Display; Physicians; Physiological; Plasma; Plasmapheresis; Process; Prognosis; Recurrent disease; Research; Research Personnel; Role; Scientist; Site; Source; Specificity; Structure; Techniques; Temperature; Tertiary Protein Structure; Testing; 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.

项目总结/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 酶ADAMTS 13的抑制。ADAMTS 13的唯一已知底物是von Willebrand因子（VWF）。 需要ADAMTS 13切割VWF以防止超大VWF多聚体在细胞中的积累。 微血管，导致终末器官损伤和潜在的危及生命的后果。抗ADAMTS 13 IgG负责酶的抑制。绝大多数抑制性抗体靶向肿瘤细胞的一个区域， ADAMTS 13主要负责与酶切割的VWF结构域结合。然而，在这方面， 这些抗体的抑制机制目前是一个活跃的研究领域，并且不知道它们是否 主要防止底物结合或减少催化周转，或者如果不同的抗体抑制不同的 机制等最近的研究表明，iTTP患者血浆中的ADAMTS 13主要以构象存在 暴露隐藏的表位，否则当ADAMTS 13处于其潜伏状态时隐藏。当前的范式 ADAMTS 13活动将此定义为所谓的“打开”状态，而潜在状态为“关闭”。第三个国家也 似乎存在ADAMTS 13具有暴露的隐蔽事件，但也能够切割VWF;这是 在此称为“打开并灌注”状态。靶向蛋白质远端结构域的抗ADAMTS 13 IgG 似乎能够诱导“打开”和“打开并预充”状态。不同构象的作用 ADAMTS 13在iTTP的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。 疾病中的IgG。最后，还不知道是否可以通过引入能够 竞争抗ADAMTS 13 IgG与ADAMTS 13的结合。本项目旨在阐明 抑制抗ADAMTS 13抗体的机制，表征远端结构域靶向抗ADAMTS 13抗体的作用。 ADAMTS 13抗体在疾病病理生理中的作用，并探索分子模拟物的结合 抗ADAMTS 13 IgG的表位作为疾病的拯救策略。我的职业目标是成为一名 作为一名独立的研究者，医生科学家，重点是iTTP的病理生理学。我目前在 在内科学系，血液科， 堪萨斯大学医学中心（KUMC）的肿瘤和细胞治疗学， 中心我的研究导师是X博士国际知名的iTTP研究者龙正。我能得到80% 根据我和大学的协议，我有受保护的研究时间。我的职业发展计划包括 定期与我的职业顾问委员会开会，在结构生物学技术方面进行实践培训， 包括在本提案中，以及正在进行的临床责任，包括每周半天的诊所，我看到 非恶性血液病患者。