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Shaw RJ, Abrams ST, Badu S, Toh CH, Dutt T. The Highs and Lows of ADAMTS13 Activity. J Clin Med 2024; 13:5152. [PMID: 39274365 PMCID: PMC11396319 DOI: 10.3390/jcm13175152] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2024] [Revised: 08/20/2024] [Accepted: 08/28/2024] [Indexed: 09/16/2024] Open
Abstract
Severe deficiency of ADAMTS13 (<10 iu/dL) is diagnostic of thrombotic thrombocytopenic purpura (TTP) and leads to accumulation of ultra-large vWF multimers, platelet aggregation, and widespread microthrombi, which can be life-threatening. However, the clinical implications of a low ADAMTS13 activity level are not only important in an acute episode of TTP. In this article, we discuss the effects of low ADAMTS13 activity in congenital and immune-mediated TTP patients not only at presentation but once in a clinical remission. Evidence is emerging of the clinical effects of low ADAMTS13 activity in other disease areas outside of TTP, and here, we explore the wider impact of low ADAMTS13 activity on the vascular endothelium and the potential for recombinant ADAMTS13 therapy in other thrombotic disease states.
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Affiliation(s)
- Rebecca J Shaw
- Liverpool University Hospitals NHS Foundation Trust, Liverpool L7 8YE, UK
- Clinical Infection, Microbiology and Immunology, Institute of Infection, Veterinary & Ecological Sciences, University of Liverpool, Ronald Ross Building, 8 West Derby Street, Liverpool L69 7BE, UK
| | - Simon T Abrams
- Clinical Infection, Microbiology and Immunology, Institute of Infection, Veterinary & Ecological Sciences, University of Liverpool, Ronald Ross Building, 8 West Derby Street, Liverpool L69 7BE, UK
| | - Samuel Badu
- Liverpool University Hospitals NHS Foundation Trust, Liverpool L7 8YE, UK
| | - Cheng-Hock Toh
- Liverpool University Hospitals NHS Foundation Trust, Liverpool L7 8YE, UK
- Clinical Infection, Microbiology and Immunology, Institute of Infection, Veterinary & Ecological Sciences, University of Liverpool, Ronald Ross Building, 8 West Derby Street, Liverpool L69 7BE, UK
| | - Tina Dutt
- Liverpool University Hospitals NHS Foundation Trust, Liverpool L7 8YE, UK
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Yada N, Zhang Q, Bignotti A, Ye Z, Zheng XL. ADAMTS13 or Caplacizumab Reduces the Accumulation of Neutrophil Extracellular Traps and Thrombus in Whole Blood of COVID-19 Patients under Flow. Thromb Haemost 2024; 124:725-738. [PMID: 38272066 PMCID: PMC11260255 DOI: 10.1055/a-2253-9359] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2024]
Abstract
BACKGROUND Neutrophil NETosis and neutrophil extracellular traps (NETs) play a critical role in pathogenesis of coronavirus disease 2019 (COVID-19)-associated thrombosis. However, the extents and reserve of NETosis, and potential of thrombus formation under shear in whole blood of patients with COVID-19 are not fully elucidated. Neither has the role of recombinant ADAMTS13 or caplacizumab on the accumulation of NETs and thrombus in COVID-19 patients' whole blood under shear been investigated. METHODS Flow cytometry and microfluidic assay, as well as immunoassays, were employed for the study. RESULTS We demonstrated that the percentage of H3Cit + MPO+ neutrophils, indicative of NETosis, was dramatically increased in patients with severe but not critical COVID-19 compared with that in asymptomatic or mild disease controls. Upon stimulation with poly [I:C], a double strain DNA mimicking viral infection, or bacterial shigatoxin-2, the percentage of H3Cit + MPO+ neutrophils was not significantly increased in the whole blood of severe and critical COVID-19 patients compared with that of asymptomatic controls, suggesting the reduction in NETosis reserve in these patients. Microfluidic assay demonstrated that the accumulation of NETs and thrombus was significantly enhanced in the whole blood of severe/critical COVID-19 patients compared with that of asymptomatic controls. Like DNase I, recombinant ADAMTS13 or caplacizumab dramatically reduced the NETs accumulation and thrombus formation under arterial shear. CONCLUSION Significantly increased neutrophil NETosis, reduced NETosis reserve, and enhanced thrombus formation under arterial shear may play a crucial role in the pathogenesis of COVID-19-associated coagulopathy. Recombinant ADAMTS13 or caplacizumab may be explored for the treatment of COVID-19-associated thrombosis.
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Affiliation(s)
- Noritaka Yada
- Department of Pathology and Laboratory Medicine, The University of Kansas Medical Center, Kanas City, Kansas, United States
| | - Quan Zhang
- Department of Pathology and Laboratory Medicine, The University of Kansas Medical Center, Kanas City, Kansas, United States
| | - Antonia Bignotti
- Department of Pathology and Laboratory Medicine, The University of Kansas Medical Center, Kanas City, Kansas, United States
| | - Zhan Ye
- Department of Pathology and Laboratory Medicine, The University of Kansas Medical Center, Kanas City, Kansas, United States
| | - X. Long Zheng
- Department of Pathology and Laboratory Medicine, The University of Kansas Medical Center, Kanas City, Kansas, United States
- Institute of Reproductive Medicine and Developmental Sciences, The University of Kansas Medical Center, Kanas City, Kansas, United States
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Zheng XL. Novel mechanisms of action of emerging therapies of hereditary thrombotic thrombocytopenic purpura. Expert Rev Hematol 2024; 17:341-351. [PMID: 38752747 PMCID: PMC11209763 DOI: 10.1080/17474086.2024.2356763] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2024] [Accepted: 05/14/2024] [Indexed: 05/21/2024]
Abstract
INTRODUCTION Hereditary thrombotic thrombocytopenic purpura (hTTP) is caused by deficiency of plasma ADAMTS13 activity, resulting from ADAMTS13 mutations. ADAMTS13 cleaves ultra large von Willebrand factor (VWF), thus reducing its multimer sizes. Hereditary deficiency of plasma ADAMTS13 activity leads to the formation of excessive platelet-VWF aggregates in small arterioles and capillaries, resulting in hTTP. AREAS COVERED PubMed search from 1956 to 2024 using thrombotic thrombocytopenic purpura and therapy identified 3,675 articles. Only the articles relevant to the topic were selected for discussion, which focuses on pathophysiology, clinical presentations, and mechanisms of action of emerging therapeutics for hTTP. Current therapies include infusion of plasma, or coagulation factor VIII, or recombinant ADAMTS13. Emerging therapies include anti-VWF A1 aptamers or nanobody and gene therapies with adeno-associated viral vector or self-inactivated lentiviral vector or a sleeping beauty transposon system for a long-term expression of a functional ADAMTS13 enzyme. EXPERT OPINION Frequent plasma infusion remains to be the standard of care in most parts of the world, while recombinant ADAMTS13 has become the treatment of choice for hTTP in some of the Western countries. The success of gene therapies in preclinical models may hold a promise for future development of these novel approaches for a cure of hTTP.
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Affiliation(s)
- X. Long Zheng
- Department of Pathology and Laboratory Medicine and Institute of Reproductive Medicine and Developmental Sciences, the University of Kansas Medical Center, Kansas City, Kansas 66160, USA
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Zheng XL. Mechanism underlying severe deficiency of plasma ADAMTS-13 activity in immune thrombotic thrombocytopenic purpura. J Thromb Haemost 2024; 22:1358-1365. [PMID: 38360215 PMCID: PMC11055658 DOI: 10.1016/j.jtha.2024.02.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Revised: 02/02/2024] [Accepted: 02/05/2024] [Indexed: 02/17/2024]
Abstract
BACKGROUND Immune-mediated thrombotic thrombocytopenic purpura is caused by autoantibodies against ADAMTS-13, a plasma enzyme that cleaves von Willebrand factor. However, the mechanism resulting in severe deficiency of plasma ADAMTS-13 activity remains controversial. OBJECTIVES To determine the mechanism of autoantibody-mediated severe deficiency of plasma ADAMTS13 activity in immune-mediated thrombotic thrombocytopenic purpura. METHODS Fluorescence resonance energy transfer-VWF73 was used to determine plasma ADAMTS-13 activity. Enzyme-linked immunosorbent assay (ELISA) was used to determine anti-ADAMTS-13 immunoglobulin G. ELISA and capillary electrophoresis-based Western blotting were employed to assess plasma ADAMTS-13 antigen. RESULTS We showed that plasma ADAMTS-13 antigen levels varied substantially in the samples collected on admission despite all showing plasma ADAMTS-13 activity of <10 IU/dL (or <10% of normal level) using either ELISA or Western blotting. More severe deficiency of plasma ADAMTS-13 antigen (<10%) was detected in admission samples by ELISA than by capillary Western blotting. There was a significant but moderate correlation between plasma ADAMTS-13 activity and ADAMTS-13 antigen by either assay method, suggesting that severe deficiency of plasma ADAMTS-13 activity is not entirely associated with low levels of ADAMTS-13 antigen. CONCLUSION We conclude that severe deficiency of plasma ADAMTS-13 activity primarily resulted from antibody-mediated inhibition, but the accelerated clearance of plasma ADAMTS-13 antigen via immune complexes may also contribute significantly to severe deficiency of plasma ADAMTS-13 activity in a subset of patients with acute immune-mediated thrombotic thrombocytopenic purpura.
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Affiliation(s)
- X Long Zheng
- (1)Department of Pathology and Laboratory Medicine, the University of Kansas Medical Center, Kansas City, Kansas, USA; (2)Institue of Reproductive Medicine and Developmental Sciences, the University of Kansas Medical Center, Kansas City, Kansas, USA.
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Sui J, Zheng L, Zheng XL. ADAMTS13 Biomarkers in Management of Immune Thrombotic Thrombocytopenic Purpura. Arch Pathol Lab Med 2023; 147:974-979. [PMID: 36223210 PMCID: PMC11033696 DOI: 10.5858/arpa.2022-0050-ra] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/24/2022] [Indexed: 11/06/2022]
Abstract
CONTEXT.— Immune thrombotic thrombocytopenic purpura (iTTP) is a rare but potentially fatal blood disorder resulting from acquired deficiency of plasma ADAMTS13, a metalloprotease that cleaves endothelium-derived ultralarge von Willebrand factor. Standard of care for iTTP including therapeutic plasma exchange, caplacizumab, and immunosuppressives, known as triple therapy, has led to a significant reduction in the disease-related mortality rate. The first International Society of Thrombosis and Haemostasis TTP guideline stresses the importance of having plasma ADAMTS13 activity testing in the algorithm for diagnosis and management of iTTP. However, the predictive role of assessing plasma ADAMTS13 activity and inhibitors or other ADAMTS13-related parameters in patients with acute iTTP and during remission has not been systematically evaluated. OBJECTIVE.— To review and assess the predictive values of testing plasma ADAMTS13 activity, antigen, and inhibitors or anti-ADAMTS13 immunoglobulin G at various stages of disease in outcomes of iTTP. DATA SOURCES.— Peer-reviewed publications and personal experience. CONCLUSIONS.— We conclude that assessing ADAMTS13 biomarkers is not only essential for establishing the initial diagnosis, but also crucial for risk stratification and the early detection of disease recurrence. This may guide therapeutic interventions during acute episodes and for long-term follow-up of iTTP patients.
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Affiliation(s)
- Jingrui Sui
- From the Department of Hematology, Yantai Yu Huang Ding Hospital Affiliated to Qingdao University, Shandong Province, China (Sui)
| | - Liang Zheng
- The Department of Pathology & Laboratory Medicine, University of Kansas Medical Center, Kansas City (L. Zheng, X. L. Zheng)
| | - X Long Zheng
- The Department of Pathology & Laboratory Medicine, University of Kansas Medical Center, Kansas City (L. Zheng, X. L. Zheng)
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Halkidis K, Meng C, Liu S, Mayne L, Siegel DL, Zheng XL. Mechanisms of inhibition of human monoclonal antibodies in immune thrombotic thrombocytopenic purpura. Blood 2023; 141:2993-3005. [PMID: 37023370 PMCID: PMC10315623 DOI: 10.1182/blood.2022019252] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 02/17/2023] [Accepted: 03/12/2023] [Indexed: 04/08/2023] Open
Abstract
Antibody binding to a plasma metalloprotease, a disintegrin and metalloproteinase with thrombospondin type 1 repeats 13 (ADAMTS13), is necessary for the development of immune thrombotic thrombocytopenic purpura (iTTP). Inhibition of ADAMTS13-mediated von Willebrand factor (VWF) cleavage by such antibodies clearly plays a role in the pathophysiology of the disease, although the mechanisms by which they inhibit ADAMTS13 enzymatic function are not fully understood. At least some immunoglobulin G-type antibodies appear to affect the conformational accessibility of ADAMTS13 domains involved in both substrate recognition and inhibitory antibody binding. We used single-chain fragments of the variable region previously identified via phage display from patients with iTTP to explore the mechanisms of action of inhibitory human monoclonal antibodies. Using recombinant full-length ADAMTS13, truncated ADAMTS13 variants, and native ADAMTS13 in normal human plasma, we found that, regardless of the conditions tested, all 3 inhibitory monoclonal antibodies tested affected enzyme turnover rate much more than substrate recognition of VWF. Hydrogen-to-deuterium exchange plus mass spectrometry experiments with each of these inhibitory antibodies demonstrated that residues in the active site of the catalytic domain of ADAMTS13 are differentially exposed to solvent in the presence and absence of monoclonal antibody binding. These results support the hypothesis that inhibition of ADAMTS13 in iTTP may not necessarily occur because the antibodies directly prevent VWF binding, but instead because of allosteric effects that impair VWF cleavage, likely by affecting the conformation of the catalytic center in the protease domain of ADAMTS13. Our findings provide novel insight into the mechanism of autoantibody-mediated inhibition of ADAMTS13 and pathogenesis of iTTP.
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Affiliation(s)
- Konstantine Halkidis
- Division of Hematologic Malignancies and Cellular Therapeutics, Department of Internal Medicine, The University of Kansas Medical Center, Kansas City, KS
| | - Chan Meng
- Division of Hematologic Malignancies and Cellular Therapeutics, Department of Internal Medicine, The University of Kansas Medical Center, Kansas City, KS
| | - Szumam Liu
- Department of Pathology and Laboratory Medicine, The University of Kansas Medical Center, Kansas City, KS
| | - Leland Mayne
- Department of Biochemistry and Molecular Biophysics, University of Pennsylvania, Philadelphia, PA
| | - Don L. Siegel
- Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, PA
| | - X. Long Zheng
- Department of Pathology and Laboratory Medicine, The University of Kansas Medical Center, Kansas City, KS
- Institute of Reproductive Medicine and Developmental Sciences, The University of Kansas Medical Center, Kansas City, KS
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Pillai VG, Zheng XL. A novel mechanism underlying allosteric regulation of ADAMTS-13 revealed by hydrogen-deuterium exchange plus mass spectrometry. Res Pract Thromb Haemost 2022; 7:100012. [PMID: 36852110 PMCID: PMC9958085 DOI: 10.1016/j.rpth.2022.100012] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Revised: 11/11/2022] [Accepted: 11/14/2022] [Indexed: 02/15/2023] Open
Abstract
Background ADAMTS-13, a plasma metalloprotease, cleaves von Willebrand factor. ADAMTS-13 activity appears to be regulated through allosteric inhibition by its distal C-terminus. Objectives The objective of this study was to better understand how domain-domain interactions may affect ADAMTS-13 conformations and functions. Methods We performed deuterium-hydrogen exchange plus mass spectrometry to assess the number and rate of deuterium incorporation into various peptides of full-length ADAMTS-13 and its truncated variants. Results Under physiological conditions, a bimodal distribution of deuterium incorporation was detected in the peptides from metalloprotease (217-230 and 282-304), cysteine-rich (446-482), and CUB (for complement C1r/C1s, Uegf, Bmp1) domains (1185-1214, 1313-1330, 1341-1347, 1358-1378, and 1393-1407) of full-length recombinant ADAMTS-13, but not of truncated variants. These results suggest that the full-length ADAMTS-13 undergoes conformational changes. On removal of the middle and distal C-terminal domains, the number and rate of deuterium incorporation were increased in the peptides from cysteine-rich (445-467, 467-482, and 495-503) and spacer domains (621-642 and 655-654) but decreased in the peptides from metalloprotease (115-124, 217-230, and 274-281). Moreover, most peptides, except for 217-230 and 1357-1376, exhibited a pD-dependent deuterium incorporation in the full-length ADAMTS-13, but not in the truncated variant (eg, MDTCS or T5C). These results further suggest that the bimodal deuterium incorporation observed in the peptides from the full-length ADAMTS-13 is the result of potential impact from the middle to distal C-terminal domains. Surface plasmon resonance revealed the direct binding interactions between the distal and proximal domains of ADAMTS-13. Conclusion Our results provide novel insight on how intramolecular interactions may affect conformations of ADAMTS-13, thus regulating its proteolytic functions.
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Affiliation(s)
- Vikram G. Pillai
- Department of Pathology and Laboratory Medicine, The University of Kansas Medical Center, Kansas City, USA,Department of Biophysics, Institute of Medical Sciences, Banaras Hindu University, Varanasi, India
| | - X. Long Zheng
- Department of Pathology and Laboratory Medicine, The University of Kansas Medical Center, Kansas City, USA,Institute of Reproductive Medicine and Developmental Sciences, The University of Kansas Medical Center, Kansas City, USA,Correspondence X. Long Zheng, MD, PhD, Department of Pathology and Laboratory Medicine, The University of Kansas Medical Center, 3901 Rainbow Boulevard, 5016 Delp, Kansas City, Kansas 66160, USA.
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Platelet-Neutrophil Association in NETs-Rich Areas in the Retrieved AIS Patient Thrombi. Int J Mol Sci 2022; 23:ijms232214477. [PMID: 36430952 PMCID: PMC9694992 DOI: 10.3390/ijms232214477] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Revised: 11/08/2022] [Accepted: 11/10/2022] [Indexed: 11/23/2022] Open
Abstract
Histological structure of thrombi is a strong determinant of the outcome of vascular recanalization therapy, the only treatment option for acute ischemic stroke (AIS) patients. A total of 21 AIS patients from this study after undergoing non-enhanced CT scan and multimodal MRI were treated with mechanical stent-based and manual aspiration thrombectomy, and thromboembolic retrieved from a cerebral artery. Complementary histopathological and imaging analyses were performed to understand their composition with a specific focus on fibrin, von Willebrand factor, and neutrophil extracellular traps (NETs). Though distinct RBC-rich and platelet-rich areas were found, AIS patient thrombi were overwhelmingly platelet-rich, with 90% of thrombi containing <40% total RBC-rich contents (1.5 to 37%). Structurally, RBC-rich areas were simple, consisting of tightly packed RBCs in thin fibrin meshwork with sparsely populated nucleated cells and lacked any substantial von Willebrand factor (VWF). Platelet-rich areas were structurally more complex with thick fibrin meshwork associated with VWF. Plenty of leukocytes populated the platelet-rich areas, particularly in the periphery and border areas between platelet-rich and RBC-rich areas. Platelet-rich areas showed abundant activated neutrophils (myeloperoxidase+ and neutrophil-elastase+) containing citrullinated histone-decorated DNA. Citrullinated histone-decorated DNA also accumulated extracellularly, pointing to NETosis by the activated neutrophils. Notably, NETs-containing areas showed strong reactivity to VWF, platelets, and high-mobility group box 1 (HMGB1), signifying a close interplay between these components.
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Halkidis K, Zheng XL. ADAMTS13 conformations and mechanism of inhibition in immune thrombotic thrombocytopenic purpura. J Thromb Haemost 2022; 20:2197-2203. [PMID: 35842925 PMCID: PMC9587499 DOI: 10.1111/jth.15822] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Revised: 06/29/2022] [Accepted: 07/15/2022] [Indexed: 08/31/2023]
Abstract
ADAMTS13, a plasma metalloprotease that cleaves von Willebrand factor, is crucial for normal hemostasis. Acquired autoantibody-mediated deficiency of plasma ADAMTS13 results in a potentially fatal blood disorder, immune thrombotic thrombocytopenic purpura (iTTP). Plasma ADAMTS13 protease appears to exist in multiple conformations. Under physiological conditions, plasma ADAMTS13 exists predominantly in its "closed" conformation (or latent form), which may be activated by lowering pH, ligand binding, and binding of an antibody against the distal domains of ADAMTS13. In patients with iTTP, polyclonal antibodies target at various domains of ADAMTS13. However, nearly all inhibitory antibodies bind the spacer domain, whereas antibodies that bind the distal C-terminal domains may activate ADAMTS13 through removing its allosteric inhibition. Additionally, the anti-C-terminal antibodies may alter the potency of inhibitory antibodies towards ADAMTS13 activity. This review summarizes some of the most recent knowledge about the ADAMTS13 conformation and its mechanism of inhibition by its autoantibodies.
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Affiliation(s)
- Konstantine Halkidis
- Division of Hematologic Malignancies and Cellular Therapeutics, Department of Internal Medicine, The University of Kansas Medical Center, Kansas City, Kansas, USA
| | - X. Long Zheng
- Department of Pathology and Laboratory Medicine, The University of Kansas Medical Center, Kansas City, Kansas, USA
- Institute of Reproductive and Developmental Sciences, The University of Kansas Medical Center, Kansas City, Kansas, USA
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Halkidis K, Siegel DL, Zheng XL. A human monoclonal antibody against the distal carboxyl terminus of ADAMTS-13 modulates its susceptibility to an inhibitor in thrombotic thrombocytopenic purpura. J Thromb Haemost 2021; 19:1888-1895. [PMID: 33834592 PMCID: PMC8324539 DOI: 10.1111/jth.15332] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2021] [Revised: 04/01/2021] [Accepted: 04/05/2021] [Indexed: 12/13/2022]
Abstract
BACKGROUND Immune thrombotic thrombocytopenic purpura (iTTP) is a potentially fatal thrombotic microangiopathy, resulting from a severe deficiency of plasma ADAMTS-13 (A Disintegrin And Metalloproteinase with ThromboSpondin type 1 motif, member 13) activity. IgG-type autoantibodies are primarily responsible for the inhibition of plasma ADAMTS-13 activity. However, the mechanism underlying autoantibody-mediated inhibition is not fully understood. OBJECTIVE The purpose of the present study is to determine the role of IgG autoantibodies against various carboxyl-terminal domains of ADAMTS-13 in regulating ADAMTS-13 activity and its inhibition. METHOD Various human monoclonal antibodies isolated by phage display, recombinant protein expression and purification, and biochemical analyses were employed for the study. RESULTS Our results demonstrate for the first time that a human monoclonal antibody fragment, the single chain fragment of the variable region (scFv) isolated from a patient with acute iTTP that binds the distal carboxyl-terminus of ADAMTS-13, is able to activate ADAMTS-13 and increase the proteolytic cleavage of a FRETS-VWF73 substrate; moreover, binding of such a human monoclonal antibody against the carboxyl-terminus of ADAMTS-13 to plasma ADAMTS-13 appears to modulate inhibition by another human monoclonal antibody (i.e., scFv4-20), also isolated from an iTTP patient, that targets the spacer domain of ADAMTS-13. These results provide new insights into our understanding of the pathogenesis of iTTP.
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Affiliation(s)
- Konstantine Halkidis
- Division of Hematologic Malignancies and Cellular Therapeutics, Department of Internal Medicine, University of Kansas Medical Center, Kansas City, Kansas
| | - Don L. Siegel
- Department of Pathology and Laboratory Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania
| | - X. Long Zheng
- Department of Pathology and Laboratory Medicine, University of Kansas Medical Center, Kansas City, Kansas, U.S.A
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Velásquez Pereira LC, Roose E, Graça NAG, Sinkovits G, Kangro K, Joly BS, Tellier E, Kaplanski G, Falter T, Von Auer C, Rossmann H, Feys HB, Reti M, Prohászka Z, Lämmle B, Voorberg J, Coppo P, Veyradier A, De Meyer SF, Männik A, Vanhoorelbeke K. Immunogenic hotspots in the spacer domain of ADAMTS13 in immune-mediated thrombotic thrombocytopenic purpura. J Thromb Haemost 2021; 19:478-488. [PMID: 33171004 DOI: 10.1111/jth.15170] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Revised: 10/10/2020] [Accepted: 10/28/2020] [Indexed: 01/25/2023]
Abstract
BACKGROUND Immune-mediated thrombotic thrombocytopenic purpura (iTTP) is caused by anti-ADAMTS13 autoantibodies inducing a severe deficiency of ADAMTS13. Epitope mapping studies on samples obtained during acute iTTP episodes have shown that the iTTP immune response is polyclonal, with almost all patients having autoantibodies targeting the spacer domain of ADAMTS13. OBJECTIVES To identify the immunogenic hotspots in the spacer domain of ADAMTS13. PATIENTS/METHODS A library of 11 full-length ADAMTS13 spacer hybrids was created in which amino acid regions of the spacer domain of ADAMTS13 were exchanged by the corresponding region of the spacer domain of ADAMTS1. Next, the full-length ADAMTS13 spacer hybrids were used in enzyme-linked immunosorbent assay to epitope map anti-spacer autoantibodies in 138 samples from acute and remission iTTP patients. RESULTS Sixteen different anti-spacer autoantibody profiles were identified with a similar distribution in acute and remission patients. There was no association between the anti-spacer autoantibody profiles and disease severity. Almost all iTTP samples contained anti-spacer autoantibodies against the following three regions: amino acid residues 588-592, 602-610, and 657-666 (hybrids E, G, and M). Between 31% and 57% of the samples had anti-spacer autoantibodies against amino acid regions 572-579, 629-638, 667-676 (hybrids C, J, and N). In contrast, none of the samples had anti-spacer autoantibodies against amino acid regions 556-563, 564-571, 649-656, and 677-685 (hybrids A, B, L, and O). CONCLUSION We identified three hotspot regions (amino acid regions 588-592, 602-610, and 657-666) in the spacer domain of ADAMTS13 that are targeted by anti-spacer autoantibodies found in a large cohort of iTTP patients.
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Affiliation(s)
| | - Elien Roose
- Laboratory for Thrombosis Research, IRF Life Sciences, KU Leuven Campus Kulak Kortrijk, Kortrijk, Belgium
| | - Nuno A G Graça
- Department of Molecular and Cellular Hemostasis, Sanquin Research and Landsteiner Laboratory, Academic Medical Center, University of Amsterdam, Amsterdam, the Netherlands
- Icosagen Cell Factory OÜ, Kambia vald, Tartumaa, Estonia
| | - György Sinkovits
- Department of Internal Medicine and Hematology, and Research Group of Immunology and Hematology, Hungarian Academy of Sciences and Semmelweis University, Budapest, Hungary
| | - Kadri Kangro
- Laboratory for Thrombosis Research, IRF Life Sciences, KU Leuven Campus Kulak Kortrijk, Kortrijk, Belgium
| | - Bérangère S Joly
- Service d'Hématologie biologique, Hôpital Lariboisière, Assistance Publique-Hôpitaux de Paris and EA3518, Institut de Recherche Saint Louis, Université de Paris, Paris, France
| | - Edwige Tellier
- INSERM, INRAE, C2VN, Aix-Marseille Univ, Marseille, France
- APHM, INSERM, C2VN, CHU Conception, Service de Médecine Interne et Immunologie Clinique, Aix-Marseille Univ, Marseille, France
| | | | - Tanja Falter
- Institute of Clinical Chemistry and Laboratory Medicine, University Medical Center, Johannes Gutenberg University, Mainz, Germany
- Center for Thrombosis and Hemostasis, University Medical Center of the Johannes Gutenberg University, Mainz, Germany
| | - Charis Von Auer
- Center for Thrombosis and Hemostasis, University Medical Center of the Johannes Gutenberg University, Mainz, Germany
- Department of Hematology, Oncology and Pneumology, University Medical Center of the Johannes Gutenberg University, Mainz, Germany
| | - Heidi Rossmann
- Institute of Clinical Chemistry and Laboratory Medicine, University Medical Center, Johannes Gutenberg University, Mainz, Germany
- Center for Thrombosis and Hemostasis, University Medical Center of the Johannes Gutenberg University, Mainz, Germany
| | - Hendrik B Feys
- Transfusion Research Center, Belgian Red Cross-Flanders, Ghent, Belgium
- Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium
| | - Marienn Reti
- Department of Haematology and Stem Cell Transplantation, Central Hospital of Southern Pest, National Institute of Haematology and Infectious Diseases, Budapest, Hungary
| | - Zoltán Prohászka
- Department of Internal Medicine and Hematology, and Research Group of Immunology and Hematology, Hungarian Academy of Sciences and Semmelweis University, Budapest, Hungary
| | - Bernhard Lämmle
- Center for Thrombosis and Hemostasis, University Medical Center of the Johannes Gutenberg University, Mainz, Germany
- Department of Hematology and Central Hematology Laboratory, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
- Haemostasis Research Unit, University College London, London, UK
| | - Jan Voorberg
- Department of Molecular and Cellular Hemostasis, Sanquin Research and Landsteiner Laboratory, Academic Medical Center, University of Amsterdam, Amsterdam, the Netherlands
| | - Paul Coppo
- Service d'hématologie, Hôpital Saint-Antoine, Assistance Publique - Hôpitaux de Paris, Paris, France
- Université Sorbonne Paris Cité, Paris, France
| | - Agnès Veyradier
- Service d'Hématologie biologique, Hôpital Lariboisière, Assistance Publique-Hôpitaux de Paris and EA3518, Institut de Recherche Saint Louis, Université de Paris, Paris, France
| | - Simon F De Meyer
- Laboratory for Thrombosis Research, IRF Life Sciences, KU Leuven Campus Kulak Kortrijk, Kortrijk, Belgium
| | - Andres Männik
- Icosagen Cell Factory OÜ, Kambia vald, Tartumaa, Estonia
| | - Karen Vanhoorelbeke
- Laboratory for Thrombosis Research, IRF Life Sciences, KU Leuven Campus Kulak Kortrijk, Kortrijk, Belgium
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12
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Abstract
Introduction. The signifi cance of ADAMTS-13 extends beyond its key role in the pathogenesis of thrombotic thrombocytopenic purpura (TTP); there is evidence of a relationship between a decrease in the ADAMTS-13 activity and thrombotic events in acute myocardial infarction and ischemic stroke.Aim. To generalise available information on the structure and function of the metalloprotease ADAMTS-13.General findings. The biological function of ADAMTS-13 consists in the cleavage of ultra-large von Willebrand factor (vWF) multimers. The fact that its defi ciency causes the development of TTP provides a basis for understanding the function of vWF–cleaving protease. ADAMTS-13 has a domain structure. The functional roles of most ADAMTS-13 domains, as well as the key role of the ADAMTS-13-vWF interaction in the regulation of haemostasis, are defi ned. The conformational activation of ADAMTS-13 by vWF constitutes an important aspect of its function. After getting into the bloodstream, ultra-large vWF multimers quickly adopt a closed conformation, which becomes very resistant to ADAMTS-13 proteolysis in the absence of shear stress. Ultra-large plasma vWF multimers regain their sensitivity to ADAMTS-13 after being exposed to high fl uid shear stress, which unfolds the central vWF-A2 domain. The unfolding of a vWF molecule under shear stress conditions reveals previously hidden exosites in domain A2, which gradually increase the binding affi nity between ADAMTS-13 and vWF. The mechanism underlying the production of autoantibodies against ADAMTS-13 is unknown and requires further study. The masking of cryptic epitopes in the closed conformation of ADAMTS-13 prevents the formation of autoantibodies. Early antigen recognition of ADAMTS-13 occurs through surface-exposed epitopes in the C-terminal domains. More detailed information on the mechanisms underlying the interaction between ADAMTS-13 and the vWF can improve the understanding of mechanisms involved in the regulation of the coagulation system.Conflict of interest: the authors declare no confl ict of interest.Financial disclosure: the study had no sponsorship.
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Affiliation(s)
- A. V. Koloskov
- North-Western State Medical University named after I.I. Mechnikov
| | - A. A. Mangushlo
- North-Western State Medical University named after I.I. Mechnikov
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13
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Cao W, Abdelgawwad MS, Li J, Zheng XL. Apolipoprotein B100/Low-Density Lipoprotein Regulates Proteolysis and Functions of von Willebrand Factor under Arterial Shear. Thromb Haemost 2019; 119:1933-1946. [PMID: 31493779 PMCID: PMC7814363 DOI: 10.1055/s-0039-1696713] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
BACKGROUND Proteolytic cleavage of von Willebrand factor (VWF) by a plasma a disintegrin and metalloproteinase with a thrombospondin type 1 motifs, member 13 (ADAMTS13) is regulated by shear stress and binding of coagulation factor VIII, platelets or platelet glycoprotein 1b, and ristocetin to VWF. OBJECTIVE Current study aims to identify novel VWF binding partners that may modulate VWF functions under physiological conditions. METHODS A deoxyribonucleic acid aptamer-based affinity purification of VWF, followed by tandem mass spectrometry, functional, and binding assays was employed. RESULTS Apolipoprotein B100/low-density lipoprotein (apoB100/LDL) was identified as a novel VWF-binding partner. Purified apoB100/LDL was able to accelerate the proteolytic cleavage of VWF by ADAMTS13 under shear in a concentration-dependent manner. This rate-enhancing activity was dramatically reduced when apoB100/LDL was oxidized. More interestingly, the oxidized apoB100/LDL appeared to compete with native apoB100/LDL for its enhancing activity on VWF proteolysis under shear. As a control, a purified apoA1/high-density lipoprotein (apoA1/HDL) or apoB48 exhibited a minimal or no activity enhancing VWF proteolysis by ADAMTS13 under the same conditions. Both VWF and ADAMTS13 were able to bind native or oxidized apoB100/LDL with high affinities. No binding interaction was detected between VWF (or ADAMTS13) and apoA1/HDL (or apoB48). Moreover, apoB100/LDL but not its oxidized products inhibited the adhesion of platelets to ultra large VWF released from endothelial cells under flow. Finally, significantly reduced ratios of high to low molecular weight of VWF multimers with increased levels of plasma VWF antigen were detected in LDLR-/- mice fed with high cholesterol diet. CONCLUSION These results indicate that apoB100/LDL may be a novel physiological regulator for ADAMTS13-VWF functions.
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Affiliation(s)
- Wenjing Cao
- Division of Laboratory Medicine, Department of Pathology, The University of Alabama at Birmingham, Birmingham, Alabama, United States
| | - Mohammad S. Abdelgawwad
- Division of Laboratory Medicine, Department of Pathology, The University of Alabama at Birmingham, Birmingham, Alabama, United States
| | - Jingzhi Li
- Division of Laboratory Medicine, Department of Pathology, The University of Alabama at Birmingham, Birmingham, Alabama, United States
| | - X. Long Zheng
- Division of Laboratory Medicine, Department of Pathology, The University of Alabama at Birmingham, Birmingham, Alabama, United States
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14
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Zheng L, Zhang D, Cao W, Song WC, Zheng XL. Synergistic effects of ADAMTS13 deficiency and complement activation in pathogenesis of thrombotic microangiopathy. Blood 2019; 134:1095-1105. [PMID: 31409673 PMCID: PMC6764266 DOI: 10.1182/blood.2019001040] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Accepted: 08/02/2019] [Indexed: 12/13/2022] Open
Abstract
Severe deficiency of plasma ADAMTS13 activity is the primary cause of thrombotic thrombocytopenic purpura (TTP) whereas overwhelming activation of complement via an alternative pathway results in atypical hemolytic uremic syndrome (aHUS), the prototypes of thrombotic microangiopathy (TMA). However, clinical and pathogenic distinctions between TTP and aHUS are often quite challenging. Clinical reports have suggested that complement activation may play a role in the development of TTP, which is caused by severe deficiency of plasma ADAMTS13 activity. However, the experimental evidence to support this hypothesis is still lacking. Here, we show that mice with either Adamts13 -/- or a heterozygous mutation of complement factor H (cfh) at amino acid residue of 1206 (ie, cfh W/R ) alone remain asymptomatic despite the presence of occasional microvascular thrombi in various organ tissues. However, mice carrying both Adamts13 -/- and cfh W/R exhibit thrombocytopenia, low haptoglobin, increased fragmentation of erythrocytes in peripheral blood smear, increased plasma levels of lactate dehydrogenase activity, blood urea nitrogen, and creatinine, as well as an increased mortality rate, consistent with the development of TMA. Moreover, mice with a homozygous mutation of cfh (ie, cfh R/R ) with or without Adamts13 -/- developed severe TMA. The mortality rate in mice with Adamts13 -/- cfh R/R was significantly higher than that in mice with cfh R/R alone. Histological and immunohistochemical analyses demonstrated the presence of disseminated platelet-rich thrombi in terminal arterioles and capillaries of major organ tissues in these mice that were either euthanized or died. Together, our results support a synergistic effect of severe ADAMTS13 deficiency and complement activation in pathogenesis of TMA in mice.
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Affiliation(s)
- Liang Zheng
- Division of Laboratory Medicine, Department of Pathology, The University of Alabama at Birmingham, Birmingham, AL; and
| | - Di Zhang
- Division of Laboratory Medicine, Department of Pathology, The University of Alabama at Birmingham, Birmingham, AL; and
| | - Wenjing Cao
- Division of Laboratory Medicine, Department of Pathology, The University of Alabama at Birmingham, Birmingham, AL; and
| | - Wen-Chao Song
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, The University of Pennsylvania, Philadelphia, PA
| | - X Long Zheng
- Division of Laboratory Medicine, Department of Pathology, The University of Alabama at Birmingham, Birmingham, AL; and
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15
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Abstract
von Willebrand factor (VWF) is a key player in hemostasis, acting as a carrier for factor VIII and capturing platelets at sites of vascular damage. To capture platelets, it must undergo conformational changes, both within its A1 domain and at the macromolecular level through A2 domain unfolding. Its size and this function are regulated by the metalloproteinase ADAMTS-13. Recently, it has been shown that ADAMTS-13 undergoes a conformational change upon interaction with VWF, and that this enhances its activity towards its substrate. This review summarizes recent work on these conformational transitions, describing how they are controlled. It points to their importance in hemostasis, bleeding disorders, and the developing field of therapeutic application of ADAMTS-13 as an antithrombotic agent in obstructive microvascular thrombosis and in cardiovascular disease.
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Affiliation(s)
- K. South
- Centre for HaematologyImperial College LondonLondonUK
| | - D. A. Lane
- Centre for HaematologyImperial College LondonLondonUK
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16
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Patel S, Rani A, Goyal A. Insights into the immune manipulation mechanisms of pollen allergens by protein domain profiling. Comput Biol Chem 2017; 70:31-39. [PMID: 28780227 DOI: 10.1016/j.compbiolchem.2017.07.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2017] [Revised: 04/13/2017] [Accepted: 07/26/2017] [Indexed: 11/25/2022]
Abstract
Plant pollens are airborne allergens, as their inhalation causes immune activation, leading to rhinitis, conjunctivitis, sinusitis and oral allergy syndrome. A myriad of pollen proteins belonging to profilin, expansin, polygalacturonase, glucan endoglucosidase, pectin esterase, and lipid transfer protein class have been identified. In the present in silico study, the protein domains of fifteen pollen sequences were extracted from the UniProt database and submitted to the interactive web tool SMART (Simple Modular Architecture Research Tool), for finding the protein domain profiles. Analysis of the data based on custom-made scripts revealed the conservation of pathogenic domains such as OmpH, PROF, PreSET, Bet_v_1, Cpl-7 and GAS2. Further, the retention of critical domains like CHASE2, Galanin, Dak2, DALR_1, HAMP, PWI, EFh, Excalibur, CT, PbH1, HELICc, and Kelch in pollen proteins, much like cockroach allergens and lethal viruses (such as HIV, HCV, Ebola, Dengue and Zika) was observed. Based on the shared motifs in proteins of taxonomicall-ydispersed organisms, it can be hypothesized that allergens and pathogens manipulate the human immune system in a similar manner. Allergens, being inanimate, cannot replicate in human body, and are neutralized by immune system. But, when the allergens are unremitting, the immune system becomes persistently hyper-sensitized, creating an inflammatory milieu. This study is expected to contribute to the understanding of pollen allergenicity and pathogenicity.
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Affiliation(s)
- Seema Patel
- Bioinformatics and Medical Informatics Research Center, San Diego State University, San Diego 92182, USA.
| | - Aruna Rani
- Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati 781039, Assam, India
| | - Arun Goyal
- Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati 781039, Assam, India
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17
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Patel S. Pathogenicity-associated protein domains: The fiercely-conserved evolutionary signatures. GENE REPORTS 2017; 7:127-141. [PMID: 32363241 PMCID: PMC7185390 DOI: 10.1016/j.genrep.2017.04.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2016] [Revised: 03/29/2017] [Accepted: 04/07/2017] [Indexed: 12/15/2022]
Abstract
Proteins have highly conserved domains that determine their functionality. Out of the thousands of domains discovered so far across all living forms, some of the predominant clinically-relevant domains include IENR1, HNHc, HELICc, Pro-kuma_activ, Tryp_SPc, Lactamase_B, PbH1, ChtBD3, CBM49, acidPPc, G3P_acyltransf, RPOL8c, KbaA, HAMP, HisKA, Hr1, Dak2, APC2, Citrate_ly_lig, DALR, VKc, YARHG, WR1, PWI, ZnF_BED, TUDOR, MHC_II_beta, Integrin_B_tail, Excalibur, DISIN, Cadherin, ACTIN, PROF, Robl_LC7, MIT, Kelch, GAS2, B41, Cyclin_C, Connexin_CCC, OmpH, Bac_rhodopsin, AAA, Knot1, NH, Galanin, IB, Elicitin, ACTH, Cache_2, CHASE, AgrB, PRP, IGR, and Antimicrobial21. These domains are distributed in nucleases/helicases, proteases, esterases, lipases, glycosylase, GTPases, phosphatases, methyltransferases, acyltransferase, acetyltransferase, polymerase, kinase, ligase, synthetase, oxidoreductase, protease inhibitors, nucleic acid binding proteins, adhesion and immunity-related proteins, cytoskeletal component-manipulating proteins, lipid biosynthesis and metabolism proteins, membrane-associated proteins, hormone-like and signaling proteins, etc. These domains are ubiquitous stretches or folds of the proteins in pathogens and allergens. Pathogenesis alleviation efforts can benefit enormously if the characteristics of these domains are known. Hence, this review catalogs and discusses the role of such pivotal domains, suggesting hypotheses for better understanding of pathogenesis at molecular level. Proteins have highly conserved regions or domains across pathogens and allergens. Knowledge on these critical domains can facilitate our understanding of pathogenesis mechanisms. Such immune manipulation-related domains include IENR1, HNHc, HELICc, ACTIN, PROF, Robl_LC7, OmpH etc. These domains are presnt in enzyme, transcription regulators, adhesion proteins, and hormones. This review discusses and hypothesizes on these domains.
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Key Words
- CARDs, caspase activation and recruitment domains
- CBM, carbohydrate binding module
- CTD, C-terminal domain
- ChtBD, chitin-binding domain
- Diversification
- HNHc, homing endonucleases
- HTH, helix-turn-helix
- IENR1, intron-encoded endonuclease repeat
- Immune manipulation
- PAMPs, pathogen associated molecular patterns
- Pathogenesis
- Phylogenetic conservation
- Protein domains
- SMART, Simple Modular Architecture Research Tool
- Shuffling
- UDG, uracil DNA glycosylase
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Affiliation(s)
- Seema Patel
- Bioinformatics and Medical Informatics Research Center, San Diego State University, San Diego 92182, USA
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18
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Zhou X, Ye X, Ren Y, Mei C, Ma L, Huang J, Xu W, Wei J, Ye L, Mai W, Qian W, Meng H, Jin J, Tong H. Diagnosis and management of acquired thrombotic thrombocytopenic purpura in southeast China: a single center experience of 60 cases. Front Med 2016; 10:430-436. [DOI: 10.1007/s11684-016-0492-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2016] [Accepted: 09/01/2016] [Indexed: 12/24/2022]
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19
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Patel S. In silico analysis of Hepatitis C virus (HCV) polyprotein domains and their comparison with other pathogens and allergens to gain insight on pathogenicity mechanisms. Comput Biol Chem 2016; 65:91-102. [DOI: 10.1016/j.compbiolchem.2016.10.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Revised: 09/12/2016] [Accepted: 10/11/2016] [Indexed: 12/12/2022]
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20
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South K, Freitas MO, Lane DA. Conformational quiescence of ADAMTS-13 prevents proteolytic promiscuity. J Thromb Haemost 2016; 14:2011-2022. [PMID: 27514025 PMCID: PMC5111603 DOI: 10.1111/jth.13445] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Indexed: 11/29/2022]
Abstract
Essentials Recently, ADAMTS-13 has been shown to undergo substrate induced conformation activation. Conformational quiescence of ADAMTS-13 may serve to prevent off-target proteolysis in plasma. Conformationally active ADAMTS-13 variants are capable of proteolysing the Aα chain of fibrinogen. This should be considered as ADAMTS-13 variants are developed as potential therapeutic agents. Click to hear Dr Zheng's presentation on structure function and cofactor-dependent regulation of ADAMTS-13 SUMMARY: Background Recent work has revealed that ADAMTS-13 circulates in a 'closed' conformation, only fully interacting with von Willebrand factor (VWF) following a conformational change. We hypothesized that this conformational quiescence also maintains the substrate specificity of ADAMTS-13 and that the 'open' conformation of the protease might facilitate proteolytic promiscuity. Objectives To identify a novel substrate for a constitutively active gain of function (GoF) ADAMTS-13 variant (R568K/F592Y/R660K/Y661F/Y665F). Methods Fibrinogen proteolysis was characterized using SDS PAGE and liquid chromatography-tandem mass spectrometry (LC-MS/MS). Fibrin formation was monitored by turbidity measurements and fibrin structure visualized by confocal microscopy. Results ADAMTS-13 exhibits proteolytic activity against the Aα chain of human fibrinogen, but this is only manifest on its conformational activation. Accordingly, the GoF ADAMTS-13 variant and truncated variants such as MDTCS exhibit this activity. The cleavage site has been determined by LC-MS/MS to be Aα chain Lys225-Met226. Proteolysis of fibrinogen by GoF ADAMTS-13 impairs fibrin formation in plasma-based assays, alters clot structure and increases clot permeability. Although GoF ADAMTS-13 does not appear to proteolyse preformed cross-linked fibrin, its proteolytic activity against fibrinogen increases the susceptibility of fibrin to tissue-type plasminogen activator (t-PA)-induced lysis by plasmin and increases the fibrin clearance rate more than 8-fold compared with wild-type (WT) ADAMTS-13 (EC50 values of 3.0 ± 1.7 nm and 25.2 ± 9.7 nm, respectively) in in vitro thrombosis models. Conclusion The 'closed' conformation of ADAMTS-13 restricts its specificity and protects against fibrinogenolysis. Induced substrate promiscuity will be important as ADAMTS-13 variants are developed as potential therapeutic agents against thrombotic thrombocytopenic purpura (TTP) and other cardiovascular diseases.
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Affiliation(s)
- K South
- Centre for Haematology, Imperial College London, London, UK.
| | - M O Freitas
- Centre for Haematology, Imperial College London, London, UK
| | - D A Lane
- Centre for Haematology, Imperial College London, London, UK
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21
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Human neutrophil peptides inhibit cleavage of von Willebrand factor by ADAMTS13: a potential link of inflammation to TTP. Blood 2016; 128:110-9. [PMID: 27207796 DOI: 10.1182/blood-2015-12-688747] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2015] [Accepted: 04/30/2016] [Indexed: 12/16/2022] Open
Abstract
Infection or inflammation may precede and trigger formation of microvascular thrombosis in patients with acquired thrombotic thrombocytopenic purpura (TTP). However, the mechanism underlying this clinical observation is not fully understood. Here, we show that human neutrophil peptides (HNPs) released from activated and degranulated neutrophils inhibit proteolytic cleavage of von Willebrand factor (VWF) by ADAMTS13 in a concentration-dependent manner. Half-maximal inhibitory concentrations of native HNPs toward ADAMTS13-mediated proteolysis of peptidyl VWF73 and multimeric VWF are 3.5 μM and 45 μM, respectively. Inhibitory activity of HNPs depends on the RRY motif that is shared by the spacer domain of ADAMTS13. Native HNPs bind to VWF73 (KD = 0.72 μM), soluble VWF (KD = 0.58 μM), and ultra-large VWF on endothelial cells. Enzyme-linked immunosorbent assay (ELISA) demonstrates markedly increased plasma HNPs1-3 in most patients with acquired autoimmune TTP at presentation (median, ∼170 ng/mL; range, 58-3570; n = 19) compared with healthy controls (median, ∼23 ng/mL; range, 6-44; n = 18) (P < .0001). Liquid chromatography plus tandem mass spectrometry (LC-MS/MS) reveals statistically significant increases of HNP1, HNP2, and HNP3 in patient samples (all P values <.001). There is a good correlation between measurement of HNPs1-3 by ELISA and by LC-MS/MS (Spearman ρ = 0.7932, P < .0001). Together, these results demonstrate that HNPs1-3 may be potent inhibitors of ADAMTS13 activity, likely by binding to the central A2 domain of VWF and physically blocking ADAMTS13 binding. Our findings may provide a novel link between inflammation/infection and the onset of microvascular thrombosis in acquired TTP and potentially other immune thrombotic disorders.
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22
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ADAMTS13-mediated thrombolysis of t-PA-resistant occlusions in ischemic stroke in mice. Blood 2016; 127:2337-45. [PMID: 26929275 DOI: 10.1182/blood-2015-08-662650] [Citation(s) in RCA: 126] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2015] [Accepted: 02/18/2016] [Indexed: 12/31/2022] Open
Abstract
Rapid vascular recanalization forms the basis for successful treatment of cerebral ischemia. Currently, tissue plasminogen activator (t-PA) is the only approved thrombolytic drug for ischemic stroke. However, t-PA does not always result in efficient thrombus dissolution and subsequent blood vessel recanalization. To better understand thrombus composition, we analyzed thrombi retrieved from ischemic stroke patients and found a distinct presence of von Willebrand factor (VWF) in various samples. Thrombi contained on average 20.3% ± 10.1% VWF, and this was inversely correlated with thrombus red blood cell content. We hypothesized that ADAMTS13 can exert a thrombolytic effect in VWF-containing thrombi in the setting of stroke. To test this, we generated occlusive VWF-rich thrombi in the middle cerebral artery (MCA) of mice. Infusion of t-PA did not dissolve these MCA occlusions. Interestingly, administration of ADAMTS13 5 minutes after occlusion dose-dependently dissolved these t-PA-resistant thrombi resulting in fast restoration of MCA patency and consequently reduced cerebral infarct sizes (P < .005). Delayed ADAMTS13 administration 60 minutes after occlusion was still effective but to a lesser extent (P < .05). These data show for the first time a potent thrombolytic activity of ADAMTS13 in the setting of stroke, which might become useful in treatment of acute ischemic stroke.
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23
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Abstract
Pathogenesis of thrombotic thrombocytopenic purpura (TTP) was a mystery for over half a century until the discovery of ADAMTS13. ADAMTS13 is primarily synthesized in the liver, and its main function is to cleave von Willebrand factor (VWF) anchored on the endothelial surface, in circulation, and at the sites of vascular injury. Deficiency of plasma ADAMTS13 activity (<10%) resulting from mutations of the ADAMTS13 gene or autoantibodies against ADAMTS13 causes hereditary or acquired (idiopathic) TTP. ADAMTS13 activity is usually normal or modestly reduced (>20%) in other forms of thrombotic microangiopathy secondary to hematopoietic progenitor cell transplantation, infection, and disseminated malignancy or in hemolytic uremic syndrome. Plasma infusion or exchange remains the initial treatment of choice to date, but novel therapeutics such as recombinant ADAMTS13 and gene therapy are under development. Moreover, ADAMTS13 deficiency has been shown to be a risk factor for the development of myocardial infarction, stroke, cerebral malaria, and preeclampsia.
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Affiliation(s)
- X Long Zheng
- Department of Pathology and Laboratory Medicine, The Children's Hospital of Philadelphia and The University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania 19104;
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24
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Maino A, Siegerink B, Lotta LA, Crawley JTB, le Cessie S, Leebeek FWG, Lane DA, Lowe GDO, Peyvandi F, Rosendaal FR. Plasma ADAMTS-13 levels and the risk of myocardial infarction: an individual patient data meta-analysis. J Thromb Haemost 2015; 13:1396-404. [PMID: 26073931 DOI: 10.1111/jth.13032] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2014] [Accepted: 05/20/2015] [Indexed: 11/28/2022]
Abstract
BACKGROUND Low ADAMTS-13 levels have been repeatedly associated with an increased risk of ischemic stroke, but results concerning the risk of myocardial infarction are inconclusive. OBJECTIVES To perform an individual patient data meta-analysis from observational studies investigating the association between ADAMTS-13 levels and myocardial infarction. METHODS A one-step meta-analytic approach with random treatment effects was used to estimate pooled odds ratios (ORs) and corresponding 95% confidence intervals (CIs) adjusted for confounding. Analyses were based on dichotomous exposures, with the 5th and 1st percentiles of ADAMTS-13 antigen levels as cut-off values. Quartile analyses, with the highest quartile as a reference category, were used to assess a graded association between levels and risk ('dose' relationship). Additionally, we assessed the risk of the combined presence of low ADAMTS-13 and high von Willebrand factor (VWF) levels. RESULTS Five studies were included, yielding individual data on 1501 cases and 2258 controls (mean age of 49 years). Low ADAMTS-13 levels were associated with myocardial infarction risk, with an OR of 1.89 (95% CI 1.15-3.12) for values below the 5th percentile versus above, and an OR of 4.21 (95% CI 1.73-10.21) for values below the 1st percentile versus above. Risk appeared to be restricted to these extreme levels, as there was no graded association between ADAMTS-13 levels and myocardial infarction risk over quartiles. Finally, there was only a minor synergistic effect for the combination of low ADAMTS-13 and high VWF levels. CONCLUSIONS Low ADAMTS-13 levels are associated with an increased risk of myocardial infarction.
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Affiliation(s)
- A Maino
- Department of Clinical Epidemiology, Leiden University Medical Center, Leiden, the Netherlands
- A. Bianchi Bonomi Hemophilia and Thrombosis Center, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico Milano, Università degli Studi di Milano, Milan, Italy
| | - B Siegerink
- Department of Clinical Epidemiology, Leiden University Medical Center, Leiden, the Netherlands
- Einthoven Laboratory for Experimental Vascular Medicine, Leiden University Medical Center, Leiden, the Netherlands
- Center for Stroke Research, Charité-Universitätsmedizin, Berlin, Germany
| | - L A Lotta
- A. Bianchi Bonomi Hemophilia and Thrombosis Center, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico Milano, Università degli Studi di Milano, Milan, Italy
| | - J T B Crawley
- Centre for Haematology, Faculty of Medicine, Imperial College London, London, UK
| | - S le Cessie
- Department of Clinical Epidemiology, Leiden University Medical Center, Leiden, the Netherlands
- Department of Medical Statistics and Bioinformatics, Leiden University Medical Center, Leiden, the Netherlands
| | - F W G Leebeek
- Department of Hematology, Erasmus University Medical Center, Rotterdam, the Netherlands
| | - D A Lane
- Centre for Haematology, Faculty of Medicine, Imperial College London, London, UK
| | - G D O Lowe
- Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, UK
| | - F Peyvandi
- A. Bianchi Bonomi Hemophilia and Thrombosis Center, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico Milano, Università degli Studi di Milano, Milan, Italy
| | - F R Rosendaal
- Department of Clinical Epidemiology, Leiden University Medical Center, Leiden, the Netherlands
- Einthoven Laboratory for Experimental Vascular Medicine, Leiden University Medical Center, Leiden, the Netherlands
- Department of Thrombosis and Hemostasis, Leiden University Medical Center, Leiden, the Netherlands
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25
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Lu RN, Yang S, Wu HM, Zheng XL. Unconjugated bilirubin inhibits proteolytic cleavage of von Willebrand factor by ADAMTS13 protease. J Thromb Haemost 2015; 13:1064-72. [PMID: 25782102 PMCID: PMC4599575 DOI: 10.1111/jth.12901] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2014] [Accepted: 03/03/2015] [Indexed: 12/16/2022]
Abstract
BACKGROUND Bilirubin is a yellow breakdown product of heme catabolism. Increased serum levels of unconjugated bilirubin are conditions commonly seen in premature neonates and adults with acute hemolysis including thrombotic microangiopathy. Previous studies have shown that unconjugated bilirubin lowers plasma ADAMTS13 activity, but the mechanism is not fully understood. OBJECTIVES The study is to determine whether unconjugated bilirubin directly inhibits the cleavage of von Willebrand factor (VWF) and its analogs by ADAMTS13. METHODS Fluorogenic, surface-enhanced laser desorption/ionization time-of-flight mass spectrometric assay, and Western blotting analyses were used to address this question. RESULTS Unconjugated bilirubin inhibits the cleavage of F485-rVWF73-H, D633-rVWF73-H, and GST-rVWF71-11K by ADAMTS13 in a concentration-dependent manner with a half-maximal inhibitory concentration of ~13, ~70, and ~17 μmol L(-1) , respectively. Unconjugated bilirubin also dose-dependently inhibits the cleavage of multimeric VWF by ADAMTS13 under denaturing conditions. The inhibitory activity of bilirubin on the cleavage of D633-rVWF73-H and multimeric VWF, but not F485-rVWF73-H, was eliminated after incubation with bilirubin oxidase that converts bilirubin to biliverdin. Furthermore, plasma ADAMTS13 activity in patients with hyperbilirubinemia increased after treatment with bilirubin oxidase. CONCLUSIONS Unconjugated bilirubin directly inhibits ADAMTS13's ability to cleave both peptidyl and native VWF substrates in addition to its interference with certain fluorogenic assays. Our findings may help proper interpretation of ADAMTS13 results under pathological conditions. Whether elevated serum unconjugated bilirubin has prothrombotic effect in vivo remains to be determined in our future study.
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Affiliation(s)
- Rui-Nan Lu
- Division of Laboratory Medicine, Department of Pathology, The University of Alabama at Birmingham, Birmingham, AL
- Department of Hematology, the First Affiliated Hospital of Nanjing Medical University, Jiangsu Province Hospital, Nanjing, China
| | - Shangbin Yang
- Department of Pathology, Ohio State University, Columbus, OH
| | - Haifeng M. Wu
- Department of Pathology, Ohio State University, Columbus, OH
| | - X. Long Zheng
- Division of Laboratory Medicine, Department of Pathology, The University of Alabama at Birmingham, Birmingham, AL
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Abstract
In this issue of Blood, de Groot et al identify a hydrophobic pocket in the Cys-rich domain of ADAMTS13 that appears to interact with the hydrophobic pocket in the central A2 domain of von Willebrand factor (VWF) for its proteolysis.
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Platelet-delivered ADAMTS13 inhibits arterial thrombosis and prevents thrombotic thrombocytopenic purpura in murine models. Blood 2015; 125:3326-34. [PMID: 25800050 DOI: 10.1182/blood-2014-07-587139] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2014] [Accepted: 03/11/2015] [Indexed: 11/20/2022] Open
Abstract
ADAMTS13 metalloprotease cleaves von Willebrand factor (VWF), thereby inhibiting platelet aggregation and arterial thrombosis. An inability to cleave ultralarge VWF resulting from hereditary or acquired deficiency of plasma ADAMTS13 activity leads to a potentially fatal syndrome, thrombotic thrombocytopenic purpura (TTP). Plasma exchange is the most effective initial therapy for TTP to date. Here, we report characterization of transgenic mice expressing recombinant human ADAMTS13 (rADAMTS13) in platelets and its efficacy in inhibiting arterial thrombosis and preventing hereditary and acquired antibody-mediated TTP in murine models. Western blotting and fluorescent resonance energy transfer assay detect full-length rADAMTS13 protein and its proteolytic activity, respectively, in transgenic (Adamts13(-/-)Plt(A13)), but not in wild-type and Adamts13(-/-), platelets. The expressed rADAMTS13 is released on stimulation with thrombin and collagen, but less with 2MesADP. Platelet-delivered rADAMTS13 is able to inhibit arterial thrombosis after vascular injury and prevent the onset and progression of Shigatoxin-2 or recombinant murine VWF-induced TTP syndrome in mice despite a lack of plasma ADAMTS13 activity resulting from the ADAMTS13 gene deletion or the antibody-mediated inhibition of plasma ADAMTS13 activity. These findings provide a proof of concept that platelet-delivered ADAMTS13 may be explored as a novel treatment of arterial thrombotic disorders, including hereditary and acquired TTP, in the presence of anti-ADAMTS13 autoantibodies.
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Lee M, Keener J, Xiao J, Long Zheng X, Rodgers GM. ADAMTS13 and its variants promote angiogenesis via upregulation of VEGF and VEGFR2. Cell Mol Life Sci 2015; 72:349-56. [PMID: 24950743 PMCID: PMC11113207 DOI: 10.1007/s00018-014-1667-3] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2013] [Revised: 06/04/2014] [Accepted: 06/05/2014] [Indexed: 02/08/2023]
Abstract
Severe plasma ADAMTS13 deficiency results in the clinical disorder thrombotic thrombocytopenic purpura. However, other potential pathophysiological roles of ADAMTS13 in endothelial cell biology remain unexplored. The goals of this study were to understand the angiogenic pathways ADAMTS13 activates and to identify the important structural components of ADAMTS13 that stimulate angiogenesis. Incubation of human umbilical vein endothelial cells (HUVEC) with 150 ng/mL (1 nM) of recombinant human ADAMTS13 induced VEGF expression by 53 % and increased VEGF mRNA by over sixfold, both within 10 min; the measured VEGF levels steadily decreased over 2 h, as shown by Western blot and ELISA. Phosphorylation of VEGFR2 was significantly enhanced in HUVEC after incubation with ADAMTS13 (1 nM). Structure-function analysis showed that an ADAMTS13 variant containing thrombospondin type 1 (TSP1) 2-8 repeats (TSP1 2-8), TSP1 2-8 plus CUB domains (TSP1 2-8 plus CUB), or TSP1 5-8 repeats plus CUB domains (TSP1 5-8 plus CUB) increased HUVEC proliferation by 41-54 % as compared to the EBM-2 controls. Chemotaxis assays further demonstrated that the TSP1 domains of ADAMTS13 increased HUVEC migration by 2.65-fold. Incubation of HUVEC with both ADAMTS13 variants containing TSP1 repeats and anti-VEGF IgG abrogated the enhanced effect of ADAMTS13 on proliferation, migration, and VEGFR2 phosphorylation. In conclusion, ADAMTS13-induced endothelial cell angiogenesis occurs via the upregulation of VEGF and phosphorylation of VEGFR2. This angiogenic activity depends on the C-terminal TSP1 repeats of ADAMTS13.
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Affiliation(s)
- Manfai Lee
- Division of Hematology and Hematologic Malignancies, University of Utah Health Sciences Center, 30 N 1900 E Room 5C402, Salt Lake City, UT, 84132, USA,
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29
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Hanby HA, Zheng XL. Current status in diagnosis and treatment of hereditary thrombotic thrombocytopenic purpura. ACTA ACUST UNITED AC 2014; 3. [PMID: 25343060 DOI: 10.4172/2161-1041.1000e108] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Hayley A Hanby
- The Cell and Molecular Biology Graduate Group and Department of Pathology and Laboratory Medicine, The Children's Hospital of Philadelphia and The University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, Tel. 215-590-3565; Fax. 267-426-5165
| | - X Long Zheng
- The Cell and Molecular Biology Graduate Group and Department of Pathology and Laboratory Medicine, The Children's Hospital of Philadelphia and The University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, Tel. 215-590-3565; Fax. 267-426-5165
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30
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Bao J, Xiao J, Mao Y, Zheng XL. Carboxyl terminus of ADAMTS13 directly inhibits platelet aggregation and ultra large von Willebrand factor string formation under flow in a free-thiol-dependent manner. Arterioscler Thromb Vasc Biol 2013; 34:397-407. [PMID: 24357063 DOI: 10.1161/atvbaha.113.302547] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVE ADAMTS13 (A Disintegrin And Metalloprotease with Thrombospondin type 1 repeats, 13) cleaves von Willebrand factor (VWF), thereby inhibiting thrombus formation. Proteolytic cleavage relies on the amino-terminal (MDTCS) domains, but the role of the more distal carboxyl-terminal domains of ADAMTS13 is not fully understood. A previous study demonstrated the presence of multiple surface-exposed free sulfhydryls on ADAMTS13 that seemed to interact with those on VWF under shear. Here, we determined the physiological relevance of such an interaction in antithrombotic responses under flow. APPROACH AND RESULTS A microfluidic assay demonstrated that a carboxyl-terminal fragment of ADAMTS13, comprising either 2 to 8 thrombospondin type 1 (TSP1) repeats and CUB domains (T2C) or 5 to 8 Thrombospondin type 1 (TSP1) repeats and CUB domains (T5C), directly inhibited platelet adhesion/aggregation on a collagen surface under arterial shear. In addition, an intravital microscopic imaging analysis showed that the carboxyl-terminal fragment of ADAMTS13 (T2C or T5C) was capable of inhibiting the formation and elongation of platelet-decorated ultra large (UL) VWF strings and the adhesion of platelets/leukocytes on endothelium in mesenteric venules after oxidative injury. The inhibitory activity of T2C and T5C on platelet aggregation and ULVWF string formation were dependent on the presence of their surface free thiols; pretreatment of T2C and T5C or full-length ADAMTS13 with N-ethylmaleimide that reacts with free sulfhydryls abolished or significantly reduced its antithrombotic activity. CONCLUSIONS Our results demonstrate for the first time that the carboxyl terminus of ADAMTS13 has direct antithrombotic activity in a free-thiol-dependent manner. The free thiols in the carboxyl-terminal domains of ADAMTS13 may also contribute to the overall antithrombotic function of ADAMTS13 under pathophysiological conditions.
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Affiliation(s)
- Jialing Bao
- From the Department of Pathology and Laboratory Medicine, The Children's Hospital of Philadelphia (J.B., J.X., Y.M., X.L.Z.); The University of Pennsylvania Perelman School of Medicine, Philadelphia (X.L.Z.); and the Department of Obstetrics and Gynecology, Tongji Hospital, Huazhong University of Science and Technology, Wuhan, China (J.X., X.L.Z.)
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31
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Zheng XL. Structure-function and regulation of ADAMTS-13 protease. J Thromb Haemost 2013; 11 Suppl 1:11-23. [PMID: 23809107 PMCID: PMC3713533 DOI: 10.1111/jth.12221] [Citation(s) in RCA: 90] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2013] [Accepted: 03/03/2013] [Indexed: 12/11/2022]
Abstract
ADAMTS-13, a plasma reprolysin-like metalloprotease, cleaves von Willebrand factor (VWF). Severe deficiency of plasma ADAMTS-13 activity results in thrombotic thrombocytopenic purpura (TTP), while mild to moderate deficiencies of plasma ADAMTS-13 activity are emerging risk factors for developing myocardial and cerebral infarction, pre-eclampsia, and malignant malaria. Moreover, Adamts13(-/-) mice develop more severe inflammatory responses, leading to increased ischemia/perfusion injury and formation of atherosclerosis. Structure-function studies demonstrate that the N-terminal portion of ADAMTS-13 (MDTCS) is necessary and sufficient for proteolytic cleavage of VWF under various conditions and attenuation of arterial/venous thrombosis after oxidative injury. The more distal portion of ADAMTS-13 (TSP1 2-8 repeats and CUB domains) may function as a disulfide bond reductase to prevent an elongation of ultra-large VWF strings on activated endothelial cells and inhibit platelet adhesion/aggregation on collagen surface under flow. Remarkably, the proteolytic cleavage of VWF by ADAMTS-13 is accelerated by FVIII and platelets under fluid shear stress. A disruption of the interactions between FVIII (or platelet glycoprotein 1bα) and VWF dramatically impairs ADAMTS-13-dependent proteolysis of VWF in vitro and in vivo. These results suggest that FVIII and platelets may be physiological cofactors regulating VWF proteolysis. Finally, the structure-function and autoantibody mapping studies allow us to identify an ADAMTS-13 variant with increased specific activity but reduced inhibition by autoantibodies in patients with acquired TTP. Together, these findings provide novel insight into the mechanism of VWF proteolysis and tools for the therapy of acquired TTP and perhaps other arterial thrombotic disorders.
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Affiliation(s)
- X L Zheng
- Department of Pathology and Laboratory Medicine, The Children's Hospital of Philadelphia, The University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA.
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32
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AAV-mediated expression of an ADAMTS13 variant prevents shigatoxin-induced thrombotic thrombocytopenic purpura. Blood 2013; 121:3825-9, S1-3. [PMID: 23515928 DOI: 10.1182/blood-2013-02-486779] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Severe deficiency of plasma ADAMTS13 activity causes thrombotic thrombocytopenic purpura (TTP), a life-threatening syndrome for which plasma is the only effective therapy currently available. As much as 5% of TTP cases are hereditary, resulting from mutations of the ADAMTS13 gene. Here, we report the efficacy and safety of recombinant adeno-associated virus serotype 8 (AAV8)-mediated expression of a murine ADAMTS13 variant (MDTCS), truncated after the spacer domain, in a murine model of TTP. Administration of AAV8-hAAT-mdtcs at doses greater than 2.6 × 10(11) vg/kg body weight resulted in sustained expression of plasma ADAMTS13 activity at therapeutic levels. Expression of the truncated ADAMTS13 variant eliminated circulating ultralarge von Willebrand factor multimers, prevented severe thrombocytopenia, and reduced mortality in Adamts13(-/-) disease-prone mice triggered by shigatoxin-2. These data support AAV vector-mediated expression of a comparable truncated ADAMTS13 variant as a novel therapeutic approach for hereditary TTP in humans.
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33
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Affiliation(s)
- X Long Zheng
- Department of Pathology and Laboratory Medicine, The Children's Hospital of Philadelphia and The University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19194, USA
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35
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Abstract
Prevailing approaches to manage autoimmune thrombotic disorders, such as heparin-induced thrombocytopenia, antiphospholipid syndrome and thrombotic thrombocytopenic purpura, include immunosuppression and systemic anticoagulation, though neither provides optimal outcome for many patients. A different approach is suggested by the concurrence of autoantibodies and their antigenic targets in the absence of clinical disease, such as platelet factor 4 in heparin-induced thrombocytopenia and β(2)-glycoprotein-I (β(2)GPI) in antiphospholipid syndrome. The presence of autoantibodies in the absence of disease suggests that conformational changes or other alterations in endogenous protein autoantigens are required for recognition by pathogenic autoantibodies. In thrombotic thrombocytopenic purpura, the clinical impact of ADAMTS13 deficiency caused by autoantibodies likely depends on the balance between residual antigen, that is, enzyme activity, and demand imposed by local genesis of ultralarge multimers of von Willebrand factor. A corollary of these concepts is that disrupting platelet factor 4 and β(2)GPI conformation (or ultralarge multimer of von Willebrand factor oligomerization or function) might provide a disease-targeted approach to prevent thrombosis without systemic anticoagulation or immunosuppression. Validation of this approach requires a deeper understanding of how seemingly normal host proteins become antigenic or undergo changes that increase antibody avidity, and how they can be altered to retain adaptive functions while shedding epitopes prone to elicit harmful autoimmunity.
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36
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Cao W, Sabatino DE, Altynova E, Lange AM, Casina VC, Camire RM, Zheng XL. Light chain of factor VIII is sufficient for accelerating cleavage of von Willebrand factor by ADAMTS13 metalloprotease. J Biol Chem 2012; 287:32459-66. [PMID: 22854959 DOI: 10.1074/jbc.m112.390690] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We previously demonstrated that coagulation factor VIII (FVIII) accelerates proteolytic cleavage of von Willebrand factor (VWF) by A disintegrin and metalloprotease with thrombospondin type 1 repeats (ADAMTS13) under fluid shear stress. In this study, the structural elements of FVIII required for the rate-enhancing effect and the biological relevance of this cofactor activity are determined using a murine model. An isolated light chain of human FVIII (hFVIII-LC) increases proteolytic cleavage of VWF by ADAMTS13 under shear in a concentration-dependent manner. The maximal rate-enhancing effect of hFVIII-LC is ∼8-fold, which is comparable with human full-length FVIII and B-domain deleted FVIII (hFVIII-BDD). The heavy chain (hFVIII-HC) and the light chain lacking the acidic (a3) region (hFVIII-LCΔa3) have no effect in accelerating VWF proteolysis by ADAMTS13 under the same conditions. Although recombinant hFVIII-HC and hFVIII-LCΔa3 do not detectably bind immobilized VWF, recombinant hFVIII-LC binds VWF with high affinity (K(D), ∼15 nM). Moreover, ultra-large VWF multimers accumulate in the plasma of fVIII(-/-) mice after hydrodynamic challenge but not in those reconstituted with either hFVIII-BDD or hFVIII-LC. These results suggest that the light chain of FVIII, which is not biologically active for clot formation, is sufficient for accelerating proteolytic cleavage of VWF by ADAMTS13 under fluid shear stress and (patho) physiological conditions. Our findings provide novel insight into the molecular mechanism of how FVIII regulates VWF homeostasis.
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Affiliation(s)
- Wenjing Cao
- Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104, USA
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37
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Gain-of-function ADAMTS13 variants that are resistant to autoantibodies against ADAMTS13 in patients with acquired thrombotic thrombocytopenic purpura. Blood 2012; 119:3836-43. [PMID: 22289888 DOI: 10.1182/blood-2011-12-399501] [Citation(s) in RCA: 88] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Thrombotic thrombocytopenic purpura (TTP) is primarily caused by immunoglobulin G (IgG) autoantibodies against A Disintegrin And Metalloprotease with ThromboSpondin type 1 repeats, 13 (ADAMTS13). Nearly all adult idiopathic TTP patients harbor IgGs, which bind the spacer domain of ADAMTS13, a region critical for recognition and proteolysis of von Willebrand factor (VWF). We hypothesize that a modification of an exosite in the spacer domain may generate ADAMTS13 variants with reduced autoantibody binding while preserving or enhancing specific activity. Site-directed mutagenesis was used to generate a series of ADAMTS13 variants, and their functional properties were assessed. Of 24 novel ADAMTS13 variants, 2 (ie, M4, R660K/F592Y/R568K/Y661F and M5, R660K/F592Y/R568K/Y661F/Y665F) exhibited increased specific activity approximately 4- to 5-fold and approximately 10- to 12-fold cleaving a peptide VWF73 substrate and multimeric VWF, respectively. More interestingly, the gain-of-function ADAMTS13 variants were more resistant to inhibition by anti-ADAMTS13 autoantibodies from patients with acquired idiopathic TTP because of reduced binding by anti-ADAMTS13 IgGs. These results shed more light on the critical role of the exosite in the spacer domain in substrate recognition. Our findings also help understand the pathogenesis of acquired autoimmune TTP. The autoantibody-resistant ADAMTS13 variants may be further developed as a novel therapeutic for acquired TTP with inhibitors.
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