Thrombotic thrombocytopenic purpura (TTP) is a fatal syndrome. Acquired TTP is mainly caused by autoantibodies that inhibit ADAMTS13 enzyme. Plasma exchange is the only effective therapy available to date.
In Aim1 of this proposal, we will reengineer and characterize a series of novel recombinant ADAMTS13 variants that exhibit increased specific activity, but are resistant to inhibition by autoantibodies from patients with acquired TTP. The completion of this aim will provide novel insights into the structure-function relationship of ADAMTS13 and change how we treat TTP today.
In Aim 2, we propose to determine the antigenic binding epitopes at the amino acid resolution using our novel and groundbreaking deuterium exchange coupled with mass spectrometric analysis approaches. In addition, we will determine the pathogenicity of a panel of inhibitory scFV(s) in murine models of arterial thrombosis and TTP established in the laboratory. The information gained from this study may help our understanding of the molecular mechanisms of acquired TTP and the rational designing of novel recombinant ADAMTS13 variants with desired properties (such as resistance to autoantibody inhibition) for future therapy. Finally, in Aim 3, we will test the hypothesis that ectopic expression of wild-type ADAMTS13 and gain-of-function/antibody-resistant ADAMTS13 variants in platelets would target the therapeutic enzyme directly to sites of injury without being inhibited by circulating anti-ADAMTS13 antibodies. Overall, the information obtained from the completion of the proposed study will provide novel insight into the structure-function relationship of ADAMTS13, help our understandings of the mechanisms of acquired TTP, and provide novel tools for potential therapy of such a fatal TTP syndrome.

Public Health Relevance

This project aims to design and assess the biological functions of novel ADAMTS13 variants with increased specific activity but resistance to autoantibodies. We will also determine the antigenic epitopes of ADAMTS13 using novel hydrogen exchange and mass spectrometry and the pathogenicity of a panel of human monoclonal antibodies from patients with acquired thrombotic thrombocytopenic purpura (TTP). Finally, we will develop an ectopic expression of ADAMTS13 and variants in platelets and determine the role of platelet- delivered ADAMTS13 for modulation of arterial thrombosis and TTP phenotype in mouse models. The information obtained from the study will shed new light on the structure-function relationship of ADAMTS13, help understand the molecular mechanism of TTP, and provide novel tools for therapy for acquired TTP.

National Institute of Health (NIH)
National Heart, Lung, and Blood Institute (NHLBI)
Research Project (R01)
Project #
Application #
Study Section
Special Emphasis Panel (ZRG1-VH-J (02))
Program Officer
Kindzelski, Andrei L
Project Start
Project End
Budget Start
Budget End
Support Year
Fiscal Year
Total Cost
Indirect Cost
Children's Hospital of Philadelphia
United States
Zip Code
Joly, Bérangère S; Zheng, X Long; Veyradier, Agnès (2018) Understanding thrombotic microangiopathies in children. Intensive Care Med 44:1536-1538
Russell, Robert T; McDaniel, Jenny K; Cao, Wenjing et al. (2018) Low Plasma ADAMTS13 Activity Is Associated with Coagulopathy, Endothelial Cell Damage and Mortality after Severe Paediatric Trauma. Thromb Haemost 118:676-687
Abdelgawwad, Mohammad S; Cao, Wenjing; Zheng, Liang et al. (2018) Transfusion of Platelets Loaded With Recombinant ADAMTS13 (A Disintegrin and Metalloprotease With Thrombospondin Type 1 Repeats-13) Is Efficacious for Inhibiting Arterial Thrombosis Associated With Thrombotic Thrombocytopenic Purpura. Arterioscler Thromb Vasc Biol 38:2731-2743
Kumar, Monisha; Cao, Wenjing; McDaniel, Jenny K et al. (2017) Plasma ADAMTS13 activity and von Willebrand factor antigen and activity in patients with subarachnoid haemorrhage. Thromb Haemost 117:691-699
Kim, Chong H; Simmons, Sierra C; Williams III, Lance A et al. (2017) ADAMTS13 test and/or PLASMIC clinical score in management of acquired thrombotic thrombocytopenic purpura: a cost-effective analysis. Transfusion 57:2609-2618
Ueda, Yoshiyasu; Mohammed, Imran; Song, Delu et al. (2017) Murine systemic thrombophilia and hemolytic uremic syndrome from a factor H point mutation. Blood 129:1184-1196
Cao, W J; Zheng, X L (2017) Conformational quiescence of ADAMTS-13 prevents proteolytic promiscuity: comment. J Thromb Haemost 15:586-589
Nguyen, G N; George, L A; Siner, J I et al. (2017) Novel factor VIII variants with a modified furin cleavage site improve the efficacy of gene therapy for hemophilia A. J Thromb Haemost 15:110-121
Ping, Zheng; Soni, Abha; Williams 3rd, Lance A et al. (2017) Mutations in Coagulation Factor VIII Are Associated with More Favorable Outcome in Patients with Cutaneous Melanoma. TH Open 1:e113-e121
Saha, M; McDaniel, J K; Zheng, X L (2017) Thrombotic thrombocytopenic purpura: pathogenesis, diagnosis and potential novel therapeutics. J Thromb Haemost 15:1889-1900

Showing the most recent 10 out of 33 publications