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Giannakopoulos B, Krilis SA. Domain 5 of Beta 2 glycoprotein I: Friend or foe in health? Context matters. Clin Immunol 2024; 265:110282. [PMID: 38917928 DOI: 10.1016/j.clim.2024.110282] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Revised: 06/03/2024] [Accepted: 06/05/2024] [Indexed: 06/27/2024]
Abstract
Beta 2 glycoprotein I (β2GPI) is the major autoantigen in the antiphospholipid syndrome, an autoimmune disorder characterized by thrombotic and obstetric complications. The autoantibodies that target beta 2 glycoprotein I are pathogenic and contribute to disease pathogenesis. The β2GPI molecule is composed of 5 domains that are numbered 1 through to 5. Autoantibodies bind mainly to domain 1 whereas the majority of the biological functions of the β2GPI molecule in diverse processes such as apoptotic cell clearance, complement regulation, lipopolysaccharide clearance and anticoagulation have been localised to domain 5 and its unique biochemistry, reviewed in this article. The role of purified domain 5 peptide as a potential therapeutic agent in APS and ischemia reperfusion injury is discussed.
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Affiliation(s)
- Bill Giannakopoulos
- Faculty of Medicine and Health, University of New South Wales, St George and Sutherland Campus, Level 2, Pitney Building, Kogarah, Sydney, NSW 2217, Australia; Department of Rheumatology, St George Public Hospital, Kogarah, Sydney, 2217, Australia.
| | - Steven A Krilis
- Faculty of Medicine and Health, University of New South Wales, St George and Sutherland Campus, Level 2, Pitney Building, Kogarah, Sydney, NSW 2217, Australia; Department of Infectious Diseases, Immunology, and Sexual Health, St George Public Hospital, Kogarah, Sydney 2217, Australia.
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Willis R, McDonnell TCR, Pericleous C, Gonzalez EB, Schleh A, Romay-Penabad Z, Giles IP, Rahman A. PEGylated Domain I of Beta-2-Glycoprotein I Inhibits Thrombosis in a Chronic Mouse Model of the Antiphospholipid Syndrome. Front Immunol 2022; 13:842923. [PMID: 35479096 PMCID: PMC9035797 DOI: 10.3389/fimmu.2022.842923] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2021] [Accepted: 03/21/2022] [Indexed: 11/13/2022] Open
Abstract
Antiphospholipid syndrome (APS) is an autoimmune disorder in which autoantibodies cause clinical effects of vascular thrombosis and pregnancy morbidity. The only evidence-based treatments are anticoagulant medications such as warfarin and heparin. These medications have a number of disadvantages, notably risk of haemorrhage. Therefore, there is a pressing need to develop new, more focused treatments that target the actual pathogenic disease process in APS. The pathogenic antibodies exert their effects by interacting with phospholipid-binding proteins, of which the most important is beta-2-glycoprotein I. This protein has five domains, of which the N-terminal Domain I (DI) is the main site for binding of pathogenic autoantibodies. We previously demonstrated bacterial expression of human DI and showed that this product could inhibit the ability of IgG from patients with APS (APS-IgG) to promote thrombosis in a mouse model. Since DI is a small 7kDa protein, its serum half-life would be too short to be therapeutically useful. We therefore used site-specific chemical addition of polyethylene glycol (PEG) to produce a larger variant of DI (PEG-DI) and showed that PEG-DI was equally effective as the non-PEGylated DI in inhibiting thrombosis caused by passive transfer of APS-IgG in mice. In this paper, we have used a mouse model that reflects human APS much more closely than the passive transfer of APS-IgG. In this model, the mice are immunized with human beta-2-glycoprotein I and develop endogenous anti-beta-2-glycoprotein I antibodies. When submitted to a pinch stimulus at the femoral vein, these mice develop clots. Our results show that PEG-DI inhibits production of thromboses in this model and also reduces expression of tissue factor in the aortas of the mice. No toxicity was seen in mice that received PEG-DI. Therefore, these results provide further evidence supporting possible efficacy of PEG-DI as a potential treatment for APS.
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Affiliation(s)
- Rohan Willis
- Internal Medicine, University of Texas Medical Branch, Galveston, TX, United States
| | - Thomas C. R. McDonnell
- Centre for Rheumatology Research, Division of Medicine, University College London, London, United Kingdom
| | - Charis Pericleous
- Centre for Rheumatology Research, Division of Medicine, University College London, London, United Kingdom
| | - Emilio B. Gonzalez
- Internal Medicine, University of Texas Medical Branch, Galveston, TX, United States
| | - Alvaro Schleh
- Internal Medicine, University of Texas Medical Branch, Galveston, TX, United States
| | - Zurina Romay-Penabad
- Internal Medicine, University of Texas Medical Branch, Galveston, TX, United States
| | - Ian P. Giles
- Centre for Rheumatology Research, Division of Medicine, University College London, London, United Kingdom
| | - Anisur Rahman
- Centre for Rheumatology Research, Division of Medicine, University College London, London, United Kingdom
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McDonnell TCR, Willis R, Pericleous C, Ripoll VM, Giles IP, Isenberg DA, Brasier AR, Gonzalez EB, Papalardo E, Romay-Penabad Z, Jamaluddin M, Ioannou Y, Rahman A. PEGylated Domain I of Beta-2-Glycoprotein I Inhibits the Binding, Coagulopathic, and Thrombogenic Properties of IgG From Patients With the Antiphospholipid Syndrome. Front Immunol 2018; 9:2413. [PMID: 30405613 PMCID: PMC6204385 DOI: 10.3389/fimmu.2018.02413] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Accepted: 09/28/2018] [Indexed: 01/08/2023] Open
Abstract
APS is an autoimmune disease in which antiphospholipid antibodies (aPL) cause vascular thrombosis and pregnancy morbidity. In patients with APS, aPL exert pathogenic actions by binding serum beta-2-glycoprotein I (β2GPI) via its N-terminal domain I (DI). We previously showed that bacterially-expressed recombinant DI inhibits biological actions of IgG derived from serum of patients with APS (APS-IgG). DI is too small (7 kDa) to be a viable therapeutic agent. Addition of polyethylene glycol (PEGylation) to small molecules enhances the serum half-life, reduces proteolytic targeting and can decrease immunogenicity. It is a common method of tailoring pharmacokinetic parameters and has been used in the production of many therapies in the clinic. However, PEGylation of molecules may reduce their biological activity, and the size of the PEG group can alter the balance between activity and half-life extension. Here we achieve production of site-specific PEGylation of recombinant DI (PEG-DI) and describe the activities in vitro and in vivo of three variants with different size PEG groups. All variants were able to inhibit APS-IgG from: binding to whole β2GPI in ELISA, altering the clotting properties of human plasma and promoting thrombosis and tissue factor expression in mice. These findings provide an important step on the path to developing DI into a first-in-class therapeutic in APS.
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Affiliation(s)
- Thomas C. R. McDonnell
- Division of Medicine, Centre for Rheumatology Research, University College London, London, United Kingdom
| | - Rohan Willis
- Internal Medicine, University of Texas Medical Branch, Galveston, TX, United States
| | - Charis Pericleous
- Division of Medicine, Centre for Rheumatology Research, University College London, London, United Kingdom
| | - Vera M. Ripoll
- Division of Medicine, Centre for Rheumatology Research, University College London, London, United Kingdom
| | - Ian P. Giles
- Division of Medicine, Centre for Rheumatology Research, University College London, London, United Kingdom
| | - David. A. Isenberg
- Division of Medicine, Centre for Rheumatology Research, University College London, London, United Kingdom
- Arthritis Research UK Centre for Adolescent Rheumatology, UCL/UCLH/Great Ormond Street Hospital, London, United Kingdom
| | - Allan R. Brasier
- Internal Medicine, University of Texas Medical Branch, Galveston, TX, United States
| | - Emilio B. Gonzalez
- Internal Medicine, University of Texas Medical Branch, Galveston, TX, United States
| | - Elizabeth Papalardo
- Internal Medicine, University of Texas Medical Branch, Galveston, TX, United States
| | - Zurina Romay-Penabad
- Internal Medicine, University of Texas Medical Branch, Galveston, TX, United States
| | - Mohammad Jamaluddin
- Internal Medicine, University of Texas Medical Branch, Galveston, TX, United States
| | - Yiannis Ioannou
- Division of Medicine, Centre for Rheumatology Research, University College London, London, United Kingdom
- Arthritis Research UK Centre for Adolescent Rheumatology, UCL/UCLH/Great Ormond Street Hospital, London, United Kingdom
| | - Anisur Rahman
- Division of Medicine, Centre for Rheumatology Research, University College London, London, United Kingdom
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Yin D, de Laat B, Devreese KMJ, Kelchtermans H. The clinical value of assays detecting antibodies against domain I of β2-glycoprotein I in the antiphospholipid syndrome. Autoimmun Rev 2018; 17:1210-1218. [PMID: 30316989 DOI: 10.1016/j.autrev.2018.06.011] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Accepted: 06/18/2018] [Indexed: 02/07/2023]
Abstract
As the clinical symptoms of the antiphospholipid syndrome (APS) frequently occur irrespective of the syndrome, diagnosis predominantly depends on the laboratory assays measuring the level or function of antiphospholipid antibodies (aPLs). β2-glycoprotein I (β2GPI) is increasingly accepted as the most important target of aPLs. Anti-β2GPI antibodies constitute a heterogeneous population, but current in vivo and in vitro evidence show that especially the first domain (DI) of β2GPI contains an important pathogenic epitope. This epitope containing Glycine40-Arginine43 (G40-R43) has proven to be cryptic and only exposed when β2GPI is in its open conformation. A previous study demonstrated a highly variable exposure of the cryptic epitope in commercial anti-β2GPI assays, with implications on correct patient classification. Unexpectedly, recent unpublished data revealed impaired exposure of the pathogenic epitope in the commercially available anti-DI chemiluminescence immunoassay (CIA) assay detecting specific antibodies directed to DI. In this review we summarize the laboratory and clinical performance characteristics of the different anti-DI assays in published data and conclude with inconsistent results for both the correlation of anti-DI antibodies with clinical symptoms and the added value of anti-DI antibodies in the classification criteria of APS. Additionally, we hypothesize on possible explanations for the observed discrepancies. Finally, we highly advise manufacturers to use normal pooled plasma spiked with the monoclonal anti-DI antibodies to verify correct exposure of the cryptic epitope.
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Affiliation(s)
- Dongmei Yin
- Cardiovascular Research Institute Maastricht, Maastricht University Medical Center, Maastricht, the Netherlands,; Synapse Research Institute, Maastricht, the Netherlands.
| | - Bas de Laat
- Cardiovascular Research Institute Maastricht, Maastricht University Medical Center, Maastricht, the Netherlands,; Synapse Research Institute, Maastricht, the Netherlands.
| | - Katrien M J Devreese
- Coagulation Laboratory, Department of Laboratory Medicine, Ghent University Hospital, Department of Diagnostic Sciences, Ghent University, Ghent, Belgium.
| | - Hilde Kelchtermans
- Cardiovascular Research Institute Maastricht, Maastricht University Medical Center, Maastricht, the Netherlands,; Synapse Research Institute, Maastricht, the Netherlands.
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Antibodies against TFPI and protein C are associated with a severe thrombotic phenotype in patients with and without antiphospholipid syndrome. Thromb Res 2018; 170:60-68. [DOI: 10.1016/j.thromres.2018.08.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Revised: 07/17/2018] [Accepted: 08/06/2018] [Indexed: 01/06/2023]
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Al Marzooqi A, Leone A, Al Saleh J, Khamashta M. Current status and future prospects for the treatment of antiphospholipid syndrome. Expert Rev Clin Immunol 2016; 12:927-35. [PMID: 27117597 DOI: 10.1080/1744666x.2016.1178573] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Antiphospholipid syndrome (APS) is a prothrombotic disease characterized by thrombosis and pregnancy morbidity in the presence of antiphospholipid antibodies (apL). Management of thrombosis is based on long-term oral anticoagulation and patients with arterial events should be treated aggressively. Primary thrombo-prophylaxis is recommended in patients with systemic lupus erythromatosus (SLE) and obstetric APS. Obstetric APS care is based on high-risk management and treatment with aspirin and heparin. Possible future therapies include statins, hydroxychloroquine, rituximab, and new anticoagulant drugs. Current research is focused on targeting components of the complement system, interfering with aPL-mediated cell activation and using tailored peptides to block the pathogenic subpopulation of aPL.
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Affiliation(s)
| | - Alessia Leone
- b School of Medicine , University of Birmingham , Birmingham , UK
| | - Jamal Al Saleh
- a Rheumatology Department , Dubai Hospital , Dubai , UAE
| | - Munther Khamashta
- a Rheumatology Department , Dubai Hospital , Dubai , UAE.,c Lupus Research Unit, The Rayne Institute, Division of Women's Health , St Thomas' Hospital , London , UK
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