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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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2
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Hasdemir HS, Pozzi N, Tajkhorshid E. Atomistic characterization of β2-glycoprotein I domain V interaction with anionic membranes. J Thromb Haemost 2024:S1538-7836(24)00427-6. [PMID: 39047943 DOI: 10.1016/j.jtha.2024.07.010] [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: 03/20/2024] [Revised: 06/18/2024] [Accepted: 07/01/2024] [Indexed: 07/27/2024]
Abstract
BACKGROUND Interaction of β2-glycoprotein I (β2GPI) with anionic membranes is crucial in antiphospholipid syndrome (APS), implicating the role of its membrane-binding domain, domain V (DV). The mechanism of DV binding to anionic lipids is not fully understood. OBJECTIVES This study aimed to elucidate the molecular details of β2GPI DV binding to anionic membranes. METHODS We utilized molecular dynamics simulations to investigate the structural basis of anionic lipid recognition by DV. To corroborate the membrane-binding mode identified in the highly mobile membrane mimetic simulations, we conducted additional simulations using a full membrane model. RESULTS The study identified critical regions in DV, namely the lysine-rich loop and the hydrophobic loop, which are essential for membrane association via electrostatic and hydrophobic interactions, respectively. A novel lysine pair contributing to membrane binding was also discovered, providing new insights into β2GPI's membrane interaction. Simulations revealed 2 distinct binding modes of DV to the membrane, with mode 1 characterized by the insertion of the hydrophobic loop into the lipid bilayer, suggesting a dominant mechanism for membrane association. This interaction is pivotal for the pathogenesis of APS, as it facilitates the recognition of β2GPI by antiphospholipid antibodies. CONCLUSION The study advances our understanding of the molecular interactions between β2GPI's DV and anionic membranes, which are crucial for APS pathogenesis. It highlights the importance of specific regions in DV for membrane binding and reveals a predominant binding mode. These findings have significant implications for APS diagnostics and therapeutics, offering a deeper insight into the molecular basis of the syndrome.
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Affiliation(s)
- Hale S Hasdemir
- Theoretical and Computational Biophysics Group, NIH Resource for Macromolecular Modeling and Visualization, Beckman Institute for Advanced Science and Technology, University of Illinois Urbana-Champaign, Urbana, Illinois, USA; Center for Biophysics and Computational Biology, University of Illinois Urbana-Champaign, Urbana, Illinois, USA
| | - Nicola Pozzi
- Edward A. Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, St. Louis, Missouri, USA. https://www.twitter.com/LabPozzi
| | - Emad Tajkhorshid
- Theoretical and Computational Biophysics Group, NIH Resource for Macromolecular Modeling and Visualization, Beckman Institute for Advanced Science and Technology, University of Illinois Urbana-Champaign, Urbana, Illinois, USA; Center for Biophysics and Computational Biology, University of Illinois Urbana-Champaign, Urbana, Illinois, USA; Department of Biochemistry, University of Illinois Urbana-Champaign, Urbana, Illinois, USA.
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3
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Knight JS, Erkan D. Rethinking antiphospholipid syndrome to guide future management and research. Nat Rev Rheumatol 2024; 20:377-388. [PMID: 38702511 DOI: 10.1038/s41584-024-01110-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/18/2024] [Indexed: 05/06/2024]
Abstract
Antiphospholipid syndrome (APS) consists of thrombotic, non-thrombotic and obstetric clinical manifestations developing in individuals with persistent antiphospholipid antibodies (aPL). Although researchers have made progress in characterizing different clinical phenotypes of aPL-positive people, the current approach to clinical management is still mostly based on a 'one size fits all' strategy, which is derived from the results of a limited number of prospective, controlled studies. With the 2023 publication of the ACR-EULAR APS classification criteria, it is now possible to rethink APS, to lay the groundwork for subphenotyping through novel pathophysiology-informed approaches, and to set a future APS research agenda guided by unmet needs in clinical management.
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Affiliation(s)
- Jason S Knight
- Division of Rheumatology, University of Michigan, Ann Arbor, MI, USA
| | - Doruk Erkan
- Barbara Volcker Center for Women and Rheumatic Diseases, Hospital for Special Surgery, Weill Cornell Medicine, New York, NY, USA.
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Kyriukha Y, Watkins MB, Redington JM, Dastvan R, Uversky VN, Hopkins JB, Pozzi N, Korolev S. The strand exchange domain of tumor suppressor PALB2 is intrinsically disordered and promotes oligomerization-dependent DNA compaction. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.06.01.543259. [PMID: 37333393 PMCID: PMC10274692 DOI: 10.1101/2023.06.01.543259] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/20/2023]
Abstract
The Partner and Localizer of BRCA2 (PALB2) is a scaffold protein that links BRCA1 with BRCA2 to initiate homologous recombination (HR). PALB2 interaction with DNA strongly enhances HR efficiency in cells. The PALB2 DNA-binding domain (PALB2-DBD) supports strand exchange, a complex multistep reaction conducted by only a few proteins such as RecA-like recombinases and Rad52. Using bioinformatics analysis, small-angle X-ray scattering, circular dichroism, and electron paramagnetic spectroscopy, we determined that PALB2-DBD is an intrinsically disordered region (IDR) forming compact molten globule-like dimer. IDRs contribute to oligomerization synergistically with the coiled-coil interaction. Using confocal single-molecule FRET we demonstrated that PALB2-DBD compacts single-stranded DNA even in the absence of DNA secondary structures. The compaction is bimodal, oligomerization-dependent, and is driven by IDRs, suggesting a novel strand exchange mechanism. Intrinsically disordered proteins (IDPs) are prevalent in the human proteome. Novel DNA binding properties of PALB2-DBD and the complexity of strand exchange mechanism significantly expands the functional repertoire of IDPs. Multivalent interactions and bioinformatics analysis suggest that PALB2 function is likely to depend on formation of protein-nucleic acids condensates. Similar intrinsically disordered DBDs may use chaperone-like mechanism to aid formation and resolution of DNA and RNA multichain intermediates during DNA replication, repair and recombination.
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Affiliation(s)
- Yevhenii Kyriukha
- Edward A. Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, St Louis, MO
| | - Maxwell B Watkins
- The Biophysics Collaborative Access Team (BioCat), Departments of Biology and Physics, Illinois Institute of Technology, Chicago, IL
| | - Jennifer M Redington
- Edward A. Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, St Louis, MO
| | - Reza Dastvan
- Edward A. Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, St Louis, MO
| | - Vladimir N Uversky
- Department of Molecular Medicine and USF Health Byrd Alzheimer's Research Institute, Morsani College of Medicine, University of South Florida, Tampa, FL
| | - Jesse B Hopkins
- The Biophysics Collaborative Access Team (BioCat), Departments of Biology and Physics, Illinois Institute of Technology, Chicago, IL
| | - Nicola Pozzi
- Edward A. Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, St Louis, MO
| | - Sergey Korolev
- Edward A. Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, St Louis, MO
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Hasdemir HS, Pozzi N, Tajkhorshid E. Atomistic Characterization of Beta-2-Glycoprotein I Domain V Interaction with Anionic Membranes. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.19.585743. [PMID: 38562685 PMCID: PMC10983932 DOI: 10.1101/2024.03.19.585743] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
Background Interaction of beta-2-glycoprotein I ( β 2 GPI) with anionic membranes is crucial in antiphospholipid syndrome (APS), implicating the role of it's membrane bind-ing domain, Domain V (DV). The mechanism of DV binding to anionic lipids is not fully understood. Objectives This study aims to elucidate the mechanism by which DV of β 2 GPI binds to anionic membranes. Methods We utilized molecular dynamics (MD) simulations to investigate the struc-tural basis of anionic lipid recognition by DV. To corroborate the membrane-binding mode identified in the HMMM simulations, we conducted additional simulations using a full mem-brane model. Results The study identified critical regions in DV, namely the lysine-rich loop and the hydrophobic loop, essential for membrane association via electrostatic and hydrophobic interactions, respectively. A novel lysine pair contributing to membrane binding was also discovered, providing new insights into β 2 GPI's membrane interaction. Simulations revealed two distinct binding modes of DV to the membrane, with mode 1 characterized by the insertion of the hydrophobic loop into the lipid bilayer, suggesting a dominant mechanism for membrane association. This interaction is pivotal for the pathogenesis of APS, as it facilitates the recognition of β 2 GPI by antiphospholipid antibodies. Conclusion The study advances our understanding of the molecular interactions be-tween β 2 GPI's DV and anionic membranes, crucial for APS pathogenesis. It highlights the importance of specific regions in DV for membrane binding and reveals a predominant bind-ing mode. These findings have significant implications for APS diagnostics and therapeutics, offering a deeper insight into the molecular basis of the syndrome.
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Raschi E, Borghi MO, Tedesco F, Meroni PL. Antiphospholipid syndrome pathogenesis in 2023: an update of new mechanisms or just a reconsideration of the old ones? Rheumatology (Oxford) 2024; 63:SI4-SI13. [PMID: 38320591 DOI: 10.1093/rheumatology/kead603] [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: 07/28/2023] [Accepted: 10/27/2023] [Indexed: 02/08/2024] Open
Abstract
Antibodies against phospholipid (aPL)-binding proteins, in particular, beta 2 glycoprotein I (β2GPI), are diagnostic/classification and pathogenic antibodies in antiphospholipid syndrome (APS). β2GPI-aPL recognize their target on endothelium and trigger a pro-thrombotic phenotype which is amplified by circulating monocytes, platelets and neutrophils. Complement activation is required as supported by the lack of aPL-mediated effects in animal models when the complement cascade is blocked. The final result is a localized clot. A strong generalized inflammatory response is associated with catastrophic APS, the clinical variant characterized by systemic thrombotic microangiopathy. A two-hit hypothesis was suggested to explain why persistent aPL are associated with acute events only when a second hit allows antibody/complement binding by modulating β2GPI tissue presentation. β2GPI/β2GPI-aPL are also responsible for obstetric APS, being the molecule physiologically present in placental/decidual tissues. Additional mechanisms mediated by aPL with different characteristics have been reported, but their diagnostic/prognostic value is still a matter of research.
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Affiliation(s)
- Elena Raschi
- Immunorheumatology Research Laboratory, IRCCS Istituto Auxologico Italiano, Milan, Italy
| | - Maria Orietta Borghi
- Immunorheumatology Research Laboratory, IRCCS Istituto Auxologico Italiano, Milan, Italy
- Department of Clinical Sciences and Community Health, University of Milan, Milan, Italy
| | - Francesco Tedesco
- Immunorheumatology Research Laboratory, IRCCS Istituto Auxologico Italiano, Milan, Italy
| | - Pier Luigi Meroni
- Immunorheumatology Research Laboratory, IRCCS Istituto Auxologico Italiano, Milan, Italy
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Dasgupta SK, Gollamudi J, Rivera S, Poche RA, Rumbaut RE, Thiagarajan P. β2-glycoprotein I promotes the clearance of circulating mitochondria. PLoS One 2024; 19:e0293304. [PMID: 38271349 PMCID: PMC10810532 DOI: 10.1371/journal.pone.0293304] [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: 05/12/2023] [Accepted: 10/10/2023] [Indexed: 01/27/2024] Open
Abstract
β2-glycoprotein I (β2-Gp1) is a cardiolipin-binding plasma glycoprotein. It is evolutionarily conserved from invertebrates, and cardiolipin-bound β2-Gp1 is a major target of antiphospholipid antibodies seen in autoimmune disorders. Cardiolipin is almost exclusively present in mitochondria, and mitochondria are present in circulating blood. We show that β2-Gp1 binds to cell-free mitochondria (CFM) in the circulation and promotes its phagocytosis by macrophages at physiological plasma concentrations. Exogenous CFM had a short circulation time of less than 10 minutes in mice. Following infusion of CFM, β2-Gp1-deficient mice had significantly higher levels of transfused mitochondria at 5 minutes (9.9 ± 6.4 pg/ml versus 4.0 ± 2.3 pg/ml in wildtype, p = 0.01) and at 10 minutes (3.0 ± 3.6 pg/ml versus 1.0 ± 0.06 pg/ml in wild-type, p = 0.033, n = 10). In addition, the splenic macrophages had less phagocytosed CFM in β2-Gp1-deficient mice (24.4 ± 2.72% versus 35.6 ± 3.5 in wild-type, p = 0.001, n = 5). A patient with abnormal β2-Gp1, unable to bind cardiolipin, has increased CFM in blood (5.09 pg/ml versus 1.26 ± 1.35 in normal) and his plasma induced less phagocytosis of CFM by macrophages (47.3 ± 1.6% versus 54.3 ± 1.3, p = 0.01) compared to normal plasma. These results show the evolutionarily conserved β2-Gp1 is one of the mediators of the clearance of CFM in circulation.
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Affiliation(s)
- Swapan Kumar Dasgupta
- Center for Translational Research on Inflammatory Diseases (CTRID), Michael E. DeBakey Veterans Affairs Medical Center and Departments of Pathology, Baylor College of Medicine, Houston, Texas, United States of America
| | - Jahnavi Gollamudi
- Department of Medicine, Baylor College of Medicine, Houston, Texas, United States of America
| | - Stefanie Rivera
- Center for Translational Research on Inflammatory Diseases (CTRID), Michael E. DeBakey Veterans Affairs Medical Center and Departments of Pathology, Baylor College of Medicine, Houston, Texas, United States of America
| | - Ross A. Poche
- Department of Medicine Integrative Physiology, Baylor College of Medicine, Houston, Texas, United States of America
| | - Rolando E. Rumbaut
- Department of Medicine, Baylor College of Medicine, Houston, Texas, United States of America
| | - Perumal Thiagarajan
- Center for Translational Research on Inflammatory Diseases (CTRID), Michael E. DeBakey Veterans Affairs Medical Center and Departments of Pathology, Baylor College of Medicine, Houston, Texas, United States of America
- Department of Medicine, Baylor College of Medicine, Houston, Texas, United States of America
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Atsumi T, Chighizola CB, Fujieda Y, Mackie I, Radin M, Roubey R, Bertolaccini ML. 16th International congress on antiphospholipid antibodies task force report on antiphospholipid syndrome laboratory diagnostics and trends. Lupus 2023; 32:1625-1636. [PMID: 37933818 PMCID: PMC10666497 DOI: 10.1177/09612033231211820] [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] [Indexed: 11/08/2023]
Abstract
Classification criteria for antiphospholipid syndrome (APS) require IgG or IgM isotypes of the anticardiolipin (aCL) antibodies, anti-β2 glycoprotein I (anti-β2GPI) antibodies, and/or the lupus anticoagulant (LA) to satisfy the laboratory disease definition. Over the past 20 years, non-criteria antiphospholipid antibodies (aPL) directed to other proteins of the coagulation cascade (i.e. prothrombin and/or phosphatidylserine-prothrombin complex) or to some domains of β2GPI have been proposed. This task force concentrated and reviewed the literature on data including aPS/PT, antibodies to domain 4/5 of β2GPI and the newly described antibodies to protein/HLA-DR complex. In addition, we discussed testing of LA in the 'new' oral anticoagulants' era and the value of triple positivity in the risk assessment of aPL. The conclusions were presented at a special session during the 16th International Congress on aPL, Manchester, UK, September 2019.
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Affiliation(s)
- Tatsuya Atsumi
- Department of Rheumatology, Endocrinology and Nephrology, Faculty of Medicine, Hokkaido University, Sapporo, Japan
| | - Cecilia B Chighizola
- Unit of Pediatric Rheumatology, ASST G. Pini - CTO, Department of Clinical Sciences and Community Health, University of Milan, Milan, Italy
| | - Yuichiro Fujieda
- Department of Rheumatology, Endocrinology and Nephrology, Faculty of Medicine, Hokkaido University, Sapporo, Japan
| | - Ian Mackie
- Department of Haematology, Haemostasis Research Unit, University College London, London, UK
| | - Massimo Radin
- Department of Clinical and Biological Sciences, and SCDU Nephrology and Dialysis, S. Giovanni Bosco Hospital, Center of Research of Immunopathology and Rare Diseases - Coordinating Center of Piemonte and Valle d'Aosta Network for Rare Diseases, Turin, Italy
| | - Robert Roubey
- Division of Rheumatology, Allergy & Immunology, Thurston Arthritis Research Center, University of North Carolina, Chapel Hill, NC, USA
| | - Maria Laura Bertolaccini
- Academic Department of Vascular Surgery, School of Cardiovascular and Metabolic Medicine & Sciences, King's College London, London, UK
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Kumar S, Wulf J, Basore K, Pozzi N. Structural analyses of β 2-glycoprotein I: is there a circular conformation? J Thromb Haemost 2023; 21:3511-3521. [PMID: 37536570 PMCID: PMC10834832 DOI: 10.1016/j.jtha.2023.07.016] [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: 05/22/2023] [Revised: 07/10/2023] [Accepted: 07/17/2023] [Indexed: 08/05/2023]
Abstract
BACKGROUND Antiphospholipid antibodies targeting β2-glycoprotein I (β2GPI) cause thrombosis and pregnancy morbidity in antiphospholipid syndrome (APS) patients. How these antibodies recognize β2GPI remains controversial. OBJECTIVES This study aimed to elucidate the structure of β2GPI and evaluate how pathogenic anti-domain I (DI) antibodies recognize it in human plasma. METHODS β2GPI was made recombinant and purified from human plasma using different protocols. Structural and functional analyses were conducted using orthogonal techniques, namely, electron microscopy, size-exclusion chromatography, single-molecule Förster resonance energy transfer, and microfluidic diffusional sizing. RESULTS Electron microscopy and size-exclusion chromatography showed that the structure of β2GPI produced recombinantly and purified from plasma is elongated, even when subjected to conditions previously reported to favor circularization. Single-molecule Förster resonance energy transfer analyses of β2GPI labeled at positions 88 in DII and 278 in DV showed that these residues are located >90 Å apart, consistent with an elongated form. They also documented that the distance between these 2 residues did not change when the protein was reconstituted in human plasma. Microfluidic diffusional sizing documented that β2GPI binds with moderate affinity to a prototypical anti-DI antibody targeting the epitope G40-R43 despite being elongated. CONCLUSION Circulating β2GPI is elongated and, therefore, fully capable of binding to anti-DI antibodies. Binding of β2GPI to negatively charged phospholipids drives autoantibody recognition by increasing the local concentration of the antigen and not by dramatically changing its conformation. These findings clarify the structural properties of β2GPI, which have important implications for understanding APS pathogenesis and the development of APS diagnostics and therapeutics.
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Affiliation(s)
- Suresh Kumar
- Edward A. Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, St Louis, Missouri, USA
| | - John Wulf
- Washington University Center for Cellular Imaging, Washington University School of Medicine, St Louis, Missouri, USA
| | - Katherine Basore
- Washington University Center for Cellular Imaging, Washington University School of Medicine, St Louis, Missouri, USA
| | - Nicola Pozzi
- Edward A. Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, St Louis, Missouri, USA.
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Kmeťová K, Lonina E, Yalavarthi S, Levine JS, Hoy CK, Sarosh C, Gockman K, Morris AE, Tambralli A, Madison JA, Zuo Y, Subang R, Rauch J, Knight JS. Interaction of the antiphospholipid syndrome autoantigen beta-2 glycoprotein I with DNA and neutrophil extracellular traps. Clin Immunol 2023; 255:109714. [PMID: 37527733 PMCID: PMC11200149 DOI: 10.1016/j.clim.2023.109714] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Revised: 07/26/2023] [Accepted: 07/28/2023] [Indexed: 08/03/2023]
Abstract
Beta-2 glycoprotein I (β2GPI) is a phospholipid-binding plasma protein and prominent autoantigen in antiphospholipid syndrome (APS). Here, we tested the hypothesis that β2GPI might bind to not only phospholipids, but also cell-free DNA and neutrophil extracellular traps (NETs). We report that β2GPI interacts with cell-free DNA from different species, as well as NETs, in a dose-dependent manner, retarding their migration in an agarose-gel electrophoretic mobility shift assay. We confirm the direct binding interaction of β2GPI with DNA and NETs by ELISA. We also demonstrate that β2GPI colocalizes with NET strands by immunofluorescence microscopy. Finally, we provide evidence that β2GPI-DNA complexes can be detected in the plasma of APS patients, where they positively correlate with an established biomarker of NET remnants. Taken together, our findings indicate that β2GPI interacts with DNA and NETs, and suggest that this interaction may play a role as a perpetuator and/or instigator of autoimmunity in APS.
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Affiliation(s)
- Katarína Kmeťová
- Division of Rheumatology, Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA; Institute of Molecular Biomedicine, Faculty of Medicine, Comenius University, Bratislava, Slovakia
| | - Elena Lonina
- Division of Rheumatology, Department of Medicine, McGill University, Research Institute of the McGill University Health Centre, Montreal, QC, Canada
| | - Srilakshmi Yalavarthi
- Division of Rheumatology, Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA
| | - Jerrold S Levine
- Section of Nephrology, Department of Medicine, University of Illinois at Chicago, Chicago, IL, USA; Section of Nephrology, Department of Medicine, Jesse Brown Veterans Affairs Medical Center, Chicago, IL, USA
| | - Claire K Hoy
- Division of Rheumatology, Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA
| | - Cyrus Sarosh
- Division of Rheumatology, Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA
| | - Kelsey Gockman
- Division of Rheumatology, Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA
| | - Alexandra E Morris
- Division of Rheumatology, Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA
| | - Ajay Tambralli
- Division of Rheumatology, Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA
| | - Jacqueline A Madison
- Division of Rheumatology, Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA
| | - Yu Zuo
- Division of Rheumatology, Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA
| | - Rebecca Subang
- Division of Rheumatology, Department of Medicine, McGill University, Research Institute of the McGill University Health Centre, Montreal, QC, Canada
| | - Joyce Rauch
- Division of Rheumatology, Department of Medicine, McGill University, Research Institute of the McGill University Health Centre, Montreal, QC, Canada
| | - Jason S Knight
- Division of Rheumatology, Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA.
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Kyriukha Y, Watkins MB, Redington JM, Dastvan R, Uversky VN, Hopkins J, Pozzi N, Korolev S. The PALB2 DNA-binding domain is an intrinsically disordered recombinase. RESEARCH SQUARE 2023:rs.3.rs-3235465. [PMID: 37790553 PMCID: PMC10543426 DOI: 10.21203/rs.3.rs-3235465/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/05/2023]
Abstract
The Partner and Localizer of BRCA2 (PALB2) tumor suppressor is a scaffold protein that links BRCA1 with BRCA2 to initiate homologous recombination (HR). PALB2 interaction with DNA strongly enhances HR efficiency. The PALB2 DNA-binding domain (PALB2-DBD) supports DNA strand exchange, a complex multistep reaction supported by only a few protein families such as RecA-like recombinases or Rad52. The mechanisms of PALB2 DNA binding and strand exchange are unknown. We performed circular dichroism, electron paramagnetic spectroscopy, and small-angle X-ray scattering analyses and determined that PALB2-DBD is intrinsically disordered, even when bound to DNA. The intrinsically disordered nature of this domain was further supported by bioinformatics analysis. Intrinsically disordered proteins (IDPs) are prevalent in the human proteome and have many important biological functions. The complexity of the strand exchange reaction significantly expands the functional repertoire of IDPs. The results of confocal single-molecule FRET indicated that PALB2-DBD binding leads to oligomerization-dependent DNA compaction. We hypothesize that PALB2-DBD uses a chaperone-like mechanism to aid formation and resolution of complex DNA and RNA multichain intermediates during DNA replication and repair. Since PALB2-DBD alone or within the full-length PALB2 is predicted to have strong liquid-liquid phase separation (LLPS) potential, protein-nucleic acids condensates are likely to play a role in complex functionality of PALB2-DBD. Similar DNA-binding intrinsically disordered regions may represent a novel class of functional domains that evolved to function in eukaryotic nucleic acid metabolism complexes.
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Affiliation(s)
- Yevhenii Kyriukha
- Edward A. Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, St Louis, MO
| | | | - Jennifer M Redington
- Edward A. Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, St Louis, MO
| | - Reza Dastvan
- Edward A. Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, St Louis, MO
| | - Vladimir N Uversky
- Department of Molecular Medicine and USF Health Byrd Alzheimer's Research Institute, Morsani College of Medicine, University of South Florida, Tampa, FL
| | - Jesse Hopkins
- BioCat, Advanced Photon Source, Argonne National Lab, Argonne, IL
| | - Nicola Pozzi
- Edward A. Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, St Louis, MO
| | - Sergey Korolev
- Edward A. Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, St Louis, MO
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12
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Taylor A, Kumar S, Pozzi N. Forecasting the Future of Antiphospholipid Syndrome: Prospects and Challenges. MISSOURI MEDICINE 2023; 120:359-366. [PMID: 37841574 PMCID: PMC10569398] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 10/17/2023]
Abstract
Antiphospholipid syndrome (APS) is an autoimmune condition affecting young patients, primarily women, negatively impacting their quality of life. APS is under-recognized and underdiagnosed and can have devastating results if untreated, mainly due to uncontrolled thrombosis. Research in the past decades has led to several breakthroughs with important implications for clinical practice. Here, we summarize the state of APS diagnosis, treatment, pathophysiology, and research directions that hold promise for advancing diagnosis and treatment.
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Affiliation(s)
- Aberdeen Taylor
- Edward A. Doisy Department of Biochemistry & Molecular Biology, Saint Louis University School of Medicine, St. Louis, Missouri
| | - Suresh Kumar
- Edward A. Doisy Department of Biochemistry & Molecular Biology, Saint Louis University School of Medicine, St. Louis, Missouri
| | - Nicola Pozzi
- Edward A. Doisy Department of Biochemistry & Molecular Biology, Saint Louis University School of Medicine, St. Louis, Missouri
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13
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Chinnaraj M, Flaumenhaft R, Pozzi N. Reduction of protein disulfide isomerase results in open conformations and stimulates dynamic exchange between structural ensembles. J Biol Chem 2022; 298:102217. [PMID: 35780832 PMCID: PMC9352907 DOI: 10.1016/j.jbc.2022.102217] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Revised: 06/25/2022] [Accepted: 06/27/2022] [Indexed: 11/19/2022] Open
Abstract
Human protein disulfide isomerase (PDI) is an essential redox-regulated enzyme required for oxidative protein folding. It comprises four thioredoxin domains, two catalytically active (a, a’) and two inactive (b, b’), organized to form a flexible abb’a’ U-shape. Snapshots of unbound oxidized and reduced PDI have been obtained by X-ray crystallography. Yet, how PDI’s structure changes in response to the redox environment and inhibitor binding remains controversial. Here, we used multiparameter confocal single-molecule FRET to track the movements of the two catalytic domains with high temporal resolution. We found that at equilibrium, PDI visits three structurally distinct conformational ensembles, two “open” (O1 and O2) and one “closed” (C). We show that the redox environment dictates the time spent in each ensemble and the rate at which they exchange. While oxidized PDI samples O1, O2, and C more evenly and in a slower fashion, reduced PDI predominantly populates O1 and O2 and exchanges between them more rapidly, on the submillisecond timescale. These findings were not expected based on crystallographic data. Using mutational analyses, we further demonstrate that the R300-W396 cation-π interaction and active site cysteines dictate, in unexpected ways, how the catalytic domains relocate. Finally, we show that irreversible inhibitors targeting the active sites of reduced PDI did not abolish these protein dynamics but rather shifted the equilibrium toward the closed ensemble. This work introduces a new structural framework that challenges current views of PDI dynamics, helps rationalize its multifaceted role in biology, and should be considered when designing PDI-targeted therapeutics.
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Affiliation(s)
- Mathivanan Chinnaraj
- Edward A. Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, St. Louis, MO, 63104, USA
| | - Robert Flaumenhaft
- Division of Hemostasis and Thrombosis, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts 02115, USA.
| | - Nicola Pozzi
- Edward A. Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, St. Louis, MO, 63104, USA.
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14
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Yang R, Zhang J, Zhang L, Liu Y, Guo Q. Combined detection of anticardiolipin and anti-β2-glycoprotein 1 antibodies may predict pregnancy outcome. Am J Transl Res 2022; 14:1750-1756. [PMID: 35422959 PMCID: PMC8991117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Accepted: 12/24/2020] [Indexed: 06/14/2023]
Abstract
Antiphospholipid syndrome (APS) is a typical non-inflammatory autoimmune disease that is common in young women. It is characterized by the presence of the anti-cardiolipin antibody (ACA) and anti-β2 glycoprotein 1 (anti-β2-GP1) antibody and is associated with a high risk of arteriovenous thrombosis. We measured the expression of ACA and anti-β2-GP1 antibodies in the serum of pregnant women early in their pregnancy, and analyzed the pregnancy outcome of the primigravidas who were positive for both the antibodies, so as to evaluate the efficacy of the combined determination in predicting pregnancy outcome. A total of 102 pregnant women who visited the Hebei General Hospital from January 2014 to December 2017 were enrolled in the study. The serum levels of ACA and anti-β2-GP1 antibodies were determined in all the enrolled pregnant women using the enzyme-linked immunosorbent assay (ELISA) method and the correlation between positive ACA/anti-β2-GP1 antibody and the adverse pregnancy outcomes was analyzed. Meanwhile, the difference in the pregnancy outcomes between patients who were positive for ACA only, for anti-β2-GP1 only and for both of the two antibodies was also investigated. The incidence of adverse pregnancy outcomes of pregnant women who were positive for both the ACA and the anti-β2-GP1 antibodies (48.87%) was higher than that of those positive for ACA only (28.67%) and those positive for anti-β2-GP1 only (36.66%). The positive predictive value (PPV), negative predictive value (NPV), sensitivity and specificity of the combined determination of the two predictors was 81.75%, 95.84%, 88.37% and 95.92%, respectively. The combined determination of ACA and anti-β2-GP1 antibodies early in pregnancy may predict the occurrence of pregnancy outcome, with superiority over either of the two predictors alone.
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Affiliation(s)
- Rongjuan Yang
- The 7th Obstertrics Department, Shijiazhuang Gynecological & Obstetrical HospitalShijiazhuang 050000, Hebei, China
| | - Jiajia Zhang
- The 7th Obstertrics Department, Shijiazhuang Gynecological & Obstetrical HospitalShijiazhuang 050000, Hebei, China
| | - Limei Zhang
- The 7th Obstertrics Department, Shijiazhuang Gynecological & Obstetrical HospitalShijiazhuang 050000, Hebei, China
| | - Yongli Liu
- The 7th Obstertrics Department, Shijiazhuang Gynecological & Obstetrical HospitalShijiazhuang 050000, Hebei, China
| | - Qing Guo
- Obstertrics Department, Shijiazhuang Gynecological & Obstetrical HospitalShijiazhuang 050000, Hebei, China
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15
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Islabão AG, Trindade VC, da Mota LMH, Andrade DCO, Silva CA. Managing Antiphospholipid Syndrome in Children and Adolescents: Current and Future Prospects. Paediatr Drugs 2022; 24:13-27. [PMID: 34904182 PMCID: PMC8667978 DOI: 10.1007/s40272-021-00484-w] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 11/03/2021] [Indexed: 11/28/2022]
Abstract
Pediatric antiphospholipid syndrome (APS) is a rare acquired multisystem autoimmune thromboinflammatory condition characterized by thrombotic and non-thrombotic clinical manifestations. APS in children and adolescents typically presents with large-vessel thrombosis, thrombotic microangiopathy, and, rarely, obstetric morbidity. Non-thrombotic clinical manifestations are frequently seen in pediatric APS and may be present even before the vascular thrombotic events occur. We review insights into the pathogenesis of APS and discuss potential targets for therapy. The identification of multiple immunologic abnormalities in patients with APS reveals molecular targets for current or future treatment. Management strategies, especially for APS in adolescents, require screening for additional prothrombotic risk factors and consideration of counseling regarding contraceptive strategies, lifestyle recommendations, treatment adherence, and mental health issues associated with this autoimmune thrombophilia. The main goal of therapy in pediatric APS is the prevention of thrombosis. The management of acute thrombosis events in children and adolescents is the same as for primary APS, which involves isolated occurrences, and secondary APS, which is seen in association with another autoimmune disease, e.g., systemic lupus erythematosus. A pediatric hematologist should be consulted so other differential thrombophilic conditions can be eliminated. Therapy includes unfractionated heparin or low-molecular-weight heparin followed by vitamin K antagonists. Treatment of catastrophic APS involves triple therapy (anticoagulation, intravenous corticosteroid pulse therapy, and plasma exchange) and may include intravenous immunoglobulin for children and adolescents with this condition. New drugs such as eculizumab and sirolimus seem to be promising drugs for APS.
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Affiliation(s)
- Aline Garcia Islabão
- Pediatric Rheumatology Unit, Hospital da Criança de Brasília Jose Alencar, Brasília, DF Brazil ,Programa de Pós-graduação em Ciências Médicas, Faculdade de Medicina, Universidade de Brasília, Brasília, DF Brazil
| | - Vitor Cavalcanti Trindade
- Faculdade de Medicina, Children and Adolescent Institute, Hospital das Clinicas HCFMUSP, Universidade de São Paulo, Av. Dr. Enéas Carvalho de Aguiar, 647-Cerqueira César, São Paulo, SP 05403-000 Brazil
| | - Licia Maria Henrique da Mota
- Programa de Pós-graduação em Ciências Médicas, Faculdade de Medicina, Universidade de Brasília, Brasília, DF Brazil ,Rheumatology Unit, Hospital Universitário de Brasília, Universidade de Brasília, Brasília, Brazil
| | | | - Clovis Artur Silva
- Faculdade de Medicina, Children and Adolescent Institute, Hospital das Clinicas HCFMUSP, Universidade de São Paulo, Av. Dr. Enéas Carvalho de Aguiar, 647-Cerqueira César, São Paulo, SP, 05403-000, Brazil. .,Rheumatology Division, Faculdade de Medicina, Hospital das Clinicas HCFMUSP, Universidade de São Paulo, São Paulo, Brazil.
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16
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Chinnaraj M, Pengo V, Pozzi N. A Novel ELISA Assay for the Detection of Anti-Prothrombin Antibodies in Antiphospholipid Syndrome Patients at High Risk of Thrombosis. Front Immunol 2021; 12:741589. [PMID: 34567006 PMCID: PMC8455811 DOI: 10.3389/fimmu.2021.741589] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Accepted: 08/25/2021] [Indexed: 12/03/2022] Open
Abstract
Autoantibodies targeting prothrombin (aPT) can be found in antiphospholipid syndrome (APS) patients. However, their detection has proven difficult to standardize. Here, we developed a new ELISA assay to improve the identification of aPT and compared its performance with currently available anti-phosphatidylserine/prothrombin antibodies (aPS/PT) and autoantibodies targeting prothrombin bound to the plastic plate (aPT-A) assays using a cohort of 27 APS patients at high risk of thrombosis. We generated a novel prothrombin variant, ProTS525A-Biot, carrying an artificial tag at the C-terminus suitable for site-specific biotinylation and added the mutation S525A to improve stability. ProTS525A-Biot was immobilized to neutravidin-coated plates at the desired density and with a defined orientation, i.e., pointing the N-terminal fragment-1 toward the solvent. Antibodies against ProTS525A-Biot (aPT-Bio) were found in 24 out of 27 triple-positive APS patients (88%). When compared to aPS/PT and aPT-A, aPT-Bio showed an excellent linear correlation with aPS/PT (R2 = 0.85) but not with aPT-A (R2 = 0.40). Since aPS/PT but not aPT-A are an emerging biomarker of thrombosis in APS, this method may find utility for detecting pathogenic aPT in APS but also other prothrombotic conditions such as COVID-19.
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Affiliation(s)
- Mathivanan Chinnaraj
- Edward A. Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, St. Louis, MO, United States
| | - Vittorio Pengo
- Thrombosis Research Laboratory, Department of Cardiac-Thoracic-Vascular Sciences and Public Health, University of Padova, Padua, Italy.,Arianna Foundation on Anticoagulation, Bologna, Italy
| | - Nicola Pozzi
- Edward A. Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, St. Louis, MO, United States
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17
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Kumar S, Chinnaraj M, Planer W, Zuo X, Macor P, Tedesco F, Pozzi N. An allosteric redox switch in domain V of β 2-glycoprotein I controls membrane binding and anti-domain I autoantibody recognition. J Biol Chem 2021; 297:100890. [PMID: 34197876 PMCID: PMC8326733 DOI: 10.1016/j.jbc.2021.100890] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2021] [Revised: 06/09/2021] [Accepted: 06/16/2021] [Indexed: 01/27/2023] Open
Abstract
β2-glycoprotein I (β2GPI) is an abundant multidomain plasma protein that plays various roles in the clotting and complement cascades. It is also the main target of antiphospholipid antibodies (aPL) in the acquired coagulopathy known as antiphospholipid syndrome (APS). Previous studies have shown that β2GPI adopts two interconvertible biochemical conformations, oxidized and reduced, depending on the integrity of the disulfide bonds. However, the precise contribution of the disulfide bonds to β2GPI structure and function is unknown. Here, we substituted cysteine residues with serine to investigate how the disulfide bonds C32-C60 in domain I (DI) and C288-C326 in domain V (DV) regulate β2GPI's structure and function. Results of our biophysical and biochemical studies support the hypothesis that the C32-C60 disulfide bond plays a structural role, whereas the disulfide bond C288-C326 is allosteric. We demonstrate that absence of the C288-C326 bond, unlike absence of the C32-C60 bond, diminishes membrane binding without affecting the thermodynamic stability and overall structure of the protein, which remains elongated in solution. We also document that, while absence of the C32-C60 bond directly impairs recognition of β2GPI by pathogenic anti-DI antibodies, absence of the C288-C326 disulfide bond is sufficient to abolish complex formation in the presence of anionic phospholipids. We conclude that the disulfide bond C288-C326 operates as a molecular switch capable of regulating β2GPI's physiological functions in a redox-dependent manner. We propose that in APS patients with anti-DI antibodies, selective rupture of the C288-C326 disulfide bond may be a valid strategy to lower the pathogenic potential of aPL.
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Affiliation(s)
- Suresh Kumar
- Edward A. Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, St Louis, Missouri, USA
| | - Mathivanan Chinnaraj
- Edward A. Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, St Louis, Missouri, USA
| | - William Planer
- Edward A. Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, St Louis, Missouri, USA
| | - Xiaobing Zuo
- X-Ray Science Division, Argonne National Laboratory, Lemont, Illinois, USA
| | - Paolo Macor
- Department of Life Sciences, University of Trieste, Trieste, Italy
| | - Francesco Tedesco
- Istituto Auxologico Italiano, IRCCS, Laboratory of Immuno-Rheumatology, Milan, Italy
| | - Nicola Pozzi
- Edward A. Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, St Louis, Missouri, USA.
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18
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Buchholz I, McDonnell T, Nestler P, Tharad S, Kulke M, Radziszewska A, Ripoll VM, Schmidt F, Hammer E, Toca-Herrera JL, Rahman A, Delcea M. Specific domain V reduction of beta-2-glycoprotein I induces protein flexibility and alters pathogenic antibody binding. Sci Rep 2021; 11:4542. [PMID: 33633190 PMCID: PMC7907366 DOI: 10.1038/s41598-021-84021-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2020] [Accepted: 02/10/2021] [Indexed: 01/31/2023] Open
Abstract
Beta-2-glycoprotein I (β2GPI) is a blood protein and the major antigen in the autoimmune disorder antiphospholipid syndrome (APS). β2GPI exists mainly in closed or open conformations and comprises of 11 disulfides distributed across five domains. The terminal Cys288/Cys326 disulfide bond at domain V has been associated with different cysteine redox states. The role of this disulfide bond in conformational dynamics of this protein has not been investigated so far. Here, we report on the enzymatic driven reduction by thioredoxin-1 (recycled by Tris(2-carboxyethyl)phosphine; TCEP) of β2GPI. Specific reduction was demonstrated by Western blot and mass spectrometry analyses confirming majority targeting to the fifth domain of β2GPI. Atomic force microscopy images suggested that reduced β2GPI shows a slightly higher proportion of open conformation and is more flexible compared to the untreated protein as confirmed by modelling studies. We have determined a strong increase in the binding of pathogenic APS autoantibodies to reduced β2GPI as demonstrated by ELISA. Our study is relevant for understanding the effect of β2GPI reduction on the protein structure and its implications for antibody binding in APS patients.
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Affiliation(s)
- Ina Buchholz
- Institute of Biochemistry, University of Greifswald, Greifswald, Germany
- ZIK HIKE, University of Greifswald, Greifswald, Germany
| | - Thomas McDonnell
- Division of Biochemical Engineering, Bernard Katz Institute, University College London, London, UK
| | - Peter Nestler
- Institute of Physics, University of Greifswald, Greifswald, Germany
| | - Sudarat Tharad
- Institute for Biophysics, University of Natural Resources and Life Sciences Vienna, Vienna, Austria
| | - Martin Kulke
- Institute of Biochemistry, University of Greifswald, Greifswald, Germany
| | - Anna Radziszewska
- Centre for Adolescent Rheumatology Versus Arthritis at UCL, UCLH, GOSH, London, UK
- Division of Medicine, Centre for Rheumatology, University College London, London, UK
| | - Vera M Ripoll
- Division of Medicine, Centre for Rheumatology, University College London, London, UK
| | - Frank Schmidt
- Interfaculty Institute for Genetics and Functional Genomics, University of Greifswald, Greifswald, Germany
- Proteomics Core, Weill Cornell Medicine-Qatar, Doha, Qatar
| | - Elke Hammer
- Interfaculty Institute for Genetics and Functional Genomics, University of Greifswald, Greifswald, Germany
- DZHK (German Centre for Cardiovascular Research), Partner Site Greifswald, Greifswald, Germany
| | - Jose L Toca-Herrera
- Institute for Biophysics, University of Natural Resources and Life Sciences Vienna, Vienna, Austria
| | - Anisur Rahman
- Division of Medicine, Centre for Rheumatology, University College London, London, UK.
| | - Mihaela Delcea
- Institute of Biochemistry, University of Greifswald, Greifswald, Germany.
- ZIK HIKE, University of Greifswald, Greifswald, Germany.
- DZHK (German Centre for Cardiovascular Research), Partner Site Greifswald, Greifswald, Germany.
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19
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Chinnaraj M, Barrios DA, Frieden C, Heyduk T, Flaumenhaft R, Pozzi N. Bioorthogonal Chemistry Enables Single-Molecule FRET Measurements of Catalytically Active Protein Disulfide Isomerase. Chembiochem 2021; 22:134-138. [PMID: 32857455 PMCID: PMC7790914 DOI: 10.1002/cbic.202000537] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2020] [Revised: 08/24/2020] [Indexed: 12/31/2022]
Abstract
Folding of newly synthesized proteins in the endoplasmic reticulum is assisted by several families of enzymes. One such family is the protein disulfide isomerases (PDIs). PDIs are oxidoreductases, capable of forming new disulfide bonds or breaking existing ones. Structural information on PDIs unbound and bound to substrates is highly desirable for developing targeted therapeutics, yet it has been difficult to obtain by using traditional approaches because of their relatively large size and remarkable flexibility. Single-molecule FRET (smFRET) could be a powerful tool to study PDIs' structure and dynamics under conditions relevant to physiology, but its implementation has been hindered by technical challenges of position-specific fluorophore labeling. We have overcome this limitation by site-specifically engineering fluorescent dyes into human PDI, the founding member of the family. Proof-of-concept smFRET measurements of catalytically active PDI demonstrate, for the first time, the feasibility of this approach, expanding the toolkit for structural studies of PDIs.
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Affiliation(s)
- Mathivanan Chinnaraj
- Edward A. Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, 1100 South Grand Boulevard, St. Louis, MO, 63104, USA
| | - David A Barrios
- Division of Hemostasis and Thrombosis, Beth Israel Deaconess Medical Center, Harvard Medical School, 3 Blackfan Circle, Boston, MA 02115, USA
| | - Carl Frieden
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, 660 S. Euclid Avenue, St. Louis, MO 63110, USA
| | - Tomasz Heyduk
- Edward A. Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, 1100 South Grand Boulevard, St. Louis, MO, 63104, USA
| | - Robert Flaumenhaft
- Division of Hemostasis and Thrombosis, Beth Israel Deaconess Medical Center, Harvard Medical School, 3 Blackfan Circle, Boston, MA 02115, USA
| | - Nicola Pozzi
- Edward A. Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, 1100 South Grand Boulevard, St. Louis, MO, 63104, USA
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20
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Misasi R, Longo A, Recalchi S, Caissutti D, Riitano G, Manganelli V, Garofalo T, Sorice M, Capozzi A. Molecular Mechanisms of "Antiphospholipid Antibodies" and Their Paradoxical Role in the Pathogenesis of "Seronegative APS". Int J Mol Sci 2020; 21:ijms21218411. [PMID: 33182499 PMCID: PMC7665122 DOI: 10.3390/ijms21218411] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Revised: 10/30/2020] [Accepted: 11/06/2020] [Indexed: 02/06/2023] Open
Abstract
Antiphospholipid Syndrome (APS) is an autoimmune disease characterized by arterial and/or venous thrombosis and/or pregnancy morbidity, associated with circulating antiphospholipid antibodies (aPL). In some cases, patients with a clinical profile indicative of APS (thrombosis, recurrent miscarriages or fetal loss), who are persistently negative for conventional laboratory diagnostic criteria, are classified as "seronegative" APS patients (SN-APS). Several findings suggest that aPL, which target phospholipids and/or phospholipid binding proteins, mainly β-glycoprotein I (β-GPI), may contribute to thrombotic diathesis by interfering with hemostasis. Despite the strong association between aPL and thrombosis, the exact pathogenic mechanisms underlying thrombotic events and pregnancy morbidity in APS have not yet been fully elucidated and multiple mechanisms may be involved. Furthermore, in many SN-APS patients, it is possible to demonstrate the presence of unconventional aPL ("non-criteria" aPL) or to detect aPL with alternative laboratory methods. These findings allowed the scientists to study the pathogenic mechanism of SN-APS. This review is focused on the evidence showing that these antibodies may play a functional role in the signal transduction pathway(s) leading to thrombosis and pregnancy morbidity in SN-APS. A better comprehension of the molecular mechanisms triggered by aPL may drive development of potential therapeutic strategies in APS patients.
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21
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Borghi MO, Beltagy A, Garrafa E, Curreli D, Cecchini G, Bodio C, Grossi C, Blengino S, Tincani A, Franceschini F, Andreoli L, Lazzaroni MG, Piantoni S, Masneri S, Crisafulli F, Brugnoni D, Muiesan ML, Salvetti M, Parati G, Torresani E, Mahler M, Heilbron F, Pregnolato F, Pengo M, Tedesco F, Pozzi N, Meroni PL. Anti-Phospholipid Antibodies in COVID-19 Are Different From Those Detectable in the Anti-Phospholipid Syndrome. Front Immunol 2020; 11:584241. [PMID: 33178218 PMCID: PMC7593765 DOI: 10.3389/fimmu.2020.584241] [Citation(s) in RCA: 105] [Impact Index Per Article: 26.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Accepted: 09/25/2020] [Indexed: 12/14/2022] Open
Abstract
Background Critically ill patients with coronavirus disease 2019 (COVID-19) have a profound hypercoagulable state and often develop coagulopathy which leads to organ failure and death. Because of a prolonged activated partial-thromboplastin time (aPTT), a relationship with anti-phospholipid antibodies (aPLs) has been proposed, but results are controversial. Functional assays for aPL (i.e., lupus anticoagulant) can be influenced by concomitant anticoagulation and/or high levels of C reactive protein. The presence of anti-cardiolipin (aCL), anti-beta2-glycoprotein I (anti-β2GPI), and anti-phosphatidylserine/prothrombin (aPS/PT) antibodies was not investigated systematically. Epitope specificity of anti-β2GPI antibodies was not reported. Objective To evaluate the prevalence and the clinical association of aPL in a large cohort of COVID-19 patients, and to characterize the epitope specificity of anti-β2GPI antibodies. Methods ELISA and chemiluminescence assays were used to test 122 sera of patients suffering from severe COVID-19. Of them, 16 displayed major thrombotic events. Results Anti-β2GPI IgG/IgA/IgM was the most frequent in 15.6/6.6/9.0% of patients, while aCL IgG/IgM was detected in 5.7/6.6% by ELISA. Comparable values were found by chemiluminescence. aPS/PT IgG/IgM were detectable in 2.5 and 9.8% by ELISA. No association between thrombosis and aPL was found. Reactivity against domain 1 and 4-5 of β2GPI was limited to 3/58 (5.2%) tested sera for each domain and did not correlate with aCL/anti-β2GPI nor with thrombosis. Conclusions aPL show a low prevalence in COVID-19 patients and are not associated with major thrombotic events. aPL in COVID-19 patients are mainly directed against β2GPI but display an epitope specificity different from antibodies in antiphospholipid syndrome.
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Affiliation(s)
- Maria Orietta Borghi
- Immunorheumatology Research Laboratory, Istituto Auxologico Italiano, Istituto di Ricovero Cura a Carattere Scientifico (IRCCS), Milan, Italy
- Department of Clinical Sciences and Community Health, University of Milan, Milan, Italy
| | - Asmaa Beltagy
- Immunorheumatology Research Laboratory, Istituto Auxologico Italiano, Istituto di Ricovero Cura a Carattere Scientifico (IRCCS), Milan, Italy
- Rheumatology and Clinical Immunology Department, Faculty of Medicine, Alexandria University, Alexandria, Egypt
| | - Emirena Garrafa
- Department of Molecular and Translational Medicine, University of Brescia, Brescia, Italy
- Department of Laboratory Diagnostics, Azienda Socio-Sanitaria Territoriale (ASST) Spedali Civili, Brescia, Italy
| | - Daniele Curreli
- Immunorheumatology Research Laboratory, Istituto Auxologico Italiano, Istituto di Ricovero Cura a Carattere Scientifico (IRCCS), Milan, Italy
| | - Germana Cecchini
- Department of Chemical Chemistry, Istituto Auxologico Italiano, Istituto di Ricovero Cura a Carattere Scientifico (IRCCS), Milan, Italy
| | - Caterina Bodio
- Immunorheumatology Research Laboratory, Istituto Auxologico Italiano, Istituto di Ricovero Cura a Carattere Scientifico (IRCCS), Milan, Italy
| | - Claudia Grossi
- Immunorheumatology Research Laboratory, Istituto Auxologico Italiano, Istituto di Ricovero Cura a Carattere Scientifico (IRCCS), Milan, Italy
| | - Simonetta Blengino
- Department of Cardiovascular, Neural and Metabolic Sciences, Istituto Auxologico Italiano, Istituto di Ricovero Cura a Carattere Scientifico (IRCCS), San Luca Hospital, Milan, Italy
| | - Angela Tincani
- Rheumatology and Clinical Immunology Unit, Department of Clinical and Experimental Sciences, Azienda Socio-Sanitaria Territoriale (ASST) Spedali Civili and University of Brescia, Brescia, Italy
| | - Franco Franceschini
- Rheumatology and Clinical Immunology Unit, Department of Clinical and Experimental Sciences, Azienda Socio-Sanitaria Territoriale (ASST) Spedali Civili and University of Brescia, Brescia, Italy
| | - Laura Andreoli
- Rheumatology and Clinical Immunology Unit, Department of Clinical and Experimental Sciences, Azienda Socio-Sanitaria Territoriale (ASST) Spedali Civili and University of Brescia, Brescia, Italy
| | - Maria Grazia Lazzaroni
- Rheumatology and Clinical Immunology Unit, Department of Clinical and Experimental Sciences, Azienda Socio-Sanitaria Territoriale (ASST) Spedali Civili and University of Brescia, Brescia, Italy
| | - Silvia Piantoni
- Rheumatology and Clinical Immunology Unit, Department of Clinical and Experimental Sciences, Azienda Socio-Sanitaria Territoriale (ASST) Spedali Civili and University of Brescia, Brescia, Italy
| | - Stefania Masneri
- Rheumatology and Clinical Immunology Unit, Department of Clinical and Experimental Sciences, Azienda Socio-Sanitaria Territoriale (ASST) Spedali Civili and University of Brescia, Brescia, Italy
| | - Francesca Crisafulli
- Rheumatology and Clinical Immunology Unit, Department of Clinical and Experimental Sciences, Azienda Socio-Sanitaria Territoriale (ASST) Spedali Civili and University of Brescia, Brescia, Italy
| | - Duilio Brugnoni
- Department of Laboratory Diagnostics, Azienda Socio-Sanitaria Territoriale (ASST) Spedali Civili, Brescia, Italy
| | - Maria Lorenza Muiesan
- Unità Operativa Complessa (UOC) 2° Medicina, Department of Clinical and Experimental Sciences, Azienda Socio-Sanitaria Territoriale (ASST) Spedali Civili and University of Brescia, Brescia, Italy
| | - Massimo Salvetti
- Unità Operativa Complessa (UOC) 2° Medicina, Department of Clinical and Experimental Sciences, Azienda Socio-Sanitaria Territoriale (ASST) Spedali Civili and University of Brescia, Brescia, Italy
| | - Gianfranco Parati
- Department of Cardiovascular, Neural and Metabolic Sciences, Istituto Auxologico Italiano, Istituto di Ricovero Cura a Carattere Scientifico (IRCCS), San Luca Hospital, Milan, Italy
| | - Erminio Torresani
- Department of Chemical Chemistry, Istituto Auxologico Italiano, Istituto di Ricovero Cura a Carattere Scientifico (IRCCS), Milan, Italy
| | - Michael Mahler
- Research and Development, Inova Diagnostics, Inc., San Diego, CA, United States
| | - Francesca Heilbron
- Department of Cardiovascular, Neural and Metabolic Sciences, Istituto Auxologico Italiano, Istituto di Ricovero Cura a Carattere Scientifico (IRCCS), San Luca Hospital, Milan, Italy
| | - Francesca Pregnolato
- Immunorheumatology Research Laboratory, Istituto Auxologico Italiano, Istituto di Ricovero Cura a Carattere Scientifico (IRCCS), Milan, Italy
| | - Martino Pengo
- Department of Cardiovascular, Neural and Metabolic Sciences, Istituto Auxologico Italiano, Istituto di Ricovero Cura a Carattere Scientifico (IRCCS), San Luca Hospital, Milan, Italy
| | - Francesco Tedesco
- Immunorheumatology Research Laboratory, Istituto Auxologico Italiano, Istituto di Ricovero Cura a Carattere Scientifico (IRCCS), Milan, Italy
| | - Nicola Pozzi
- Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, St. Louis, MO, United States
| | - Pier Luigi Meroni
- Immunorheumatology Research Laboratory, Istituto Auxologico Italiano, Istituto di Ricovero Cura a Carattere Scientifico (IRCCS), Milan, Italy
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22
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Durigutto P, Macor P, Pozzi N, Agostinis C, Bossi F, Meroni PL, Grossi C, Borghi MO, Planer W, Garred P, Tedesco F. Complement Activation and Thrombin Generation by MBL Bound to β2-Glycoprotein I. THE JOURNAL OF IMMUNOLOGY 2020; 205:1385-1392. [PMID: 32759297 DOI: 10.4049/jimmunol.2000570] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Accepted: 07/04/2020] [Indexed: 01/23/2023]
Abstract
β2-Glycoprotein I (β2-GPI) is an abundant plasma glycoprotein with unknown physiological function and is currently recognized as the main target of antiphospholipid Abs responsible for complement activation and vascular thrombosis in patients with antiphospholipid syndrome (APS). In this study, we provide evidence that mannose-binding lectin (MBL) binds to β2-GPI in Ca++ and a dose-dependent manner and that this interaction activates complement and promotes complement-dependent thrombin generation. Surprisingly, a significant binding was observed between MBL and isolated domains II and IV of β2-GPI, whereas the carbohydrate chains, domain I and domain V, were not involved in the interaction, documenting a noncanonical binding mode between MBL and β2-GPI. Importantly, this interaction may occur on endothelial cells because binding of MBL to β2-GPI was detected on the surface of HUVECs, and colocalization of MBL with β2-GPI was observed on the endothelium of a biopsy specimen of a femoral artery from an APS patient. Because β2-GPI-mediated MBL-dependent thrombin generation was increased after priming the endothelium with TNF-α, our data suggests that this mechanism could play an important yet unrecognized role under physiological conditions and may be upregulated in pathological situations. Moreover, the complement activation and the procoagulant effects of the β2-GPI/MBL complex may contribute to amplify similar activities of anti-β2-GPI Abs in APS and possibly act independently of Abs, raising the issue of developing appropriate therapies to avoid recurrences and disability in patients at risk for these clinical conditions.
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Affiliation(s)
- Paolo Durigutto
- Laboratorio di Immuno-Reumatologia, Istituto Auxologico Italiano, Istituto di Ricerca e Cura a Carattere Scientifico, Cusano Milanino, 20095 Milan, Italy
| | - Paolo Macor
- Department of Life Sciences, University of Trieste, 34127 Trieste, Italy
| | - Nicola Pozzi
- Edward A. Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, St. Louis, MO 63104
| | - Chiara Agostinis
- Istituto Materno-Infantile, Istituto di Ricerca e Cura a Carattere Scientifico, Burlo Garofolo, 34137 Trieste, Italy
| | - Fleur Bossi
- Istituto Materno-Infantile, Istituto di Ricerca e Cura a Carattere Scientifico, Burlo Garofolo, 34137 Trieste, Italy
| | - Pier Luigi Meroni
- Laboratorio di Immuno-Reumatologia, Istituto Auxologico Italiano, Istituto di Ricerca e Cura a Carattere Scientifico, Cusano Milanino, 20095 Milan, Italy
| | - Claudia Grossi
- Laboratorio di Immuno-Reumatologia, Istituto Auxologico Italiano, Istituto di Ricerca e Cura a Carattere Scientifico, Cusano Milanino, 20095 Milan, Italy
| | - Maria O Borghi
- Laboratorio di Immuno-Reumatologia, Istituto Auxologico Italiano, Istituto di Ricerca e Cura a Carattere Scientifico, Cusano Milanino, 20095 Milan, Italy.,Department of Clinical Sciences and Community Health, University of Milan, 20122 Milan, Italy; and
| | - William Planer
- Edward A. Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, St. Louis, MO 63104
| | - Peter Garred
- Laboratory of Molecular Medicine, Department of Clinical Immunology, Rigshospitalet, Faculty of Health and Medical Sciences, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Francesco Tedesco
- Laboratorio di Immuno-Reumatologia, Istituto Auxologico Italiano, Istituto di Ricerca e Cura a Carattere Scientifico, Cusano Milanino, 20095 Milan, Italy;
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23
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Borghi MO, Beltagy A, Garrafa E, Curreli D, Cecchini G, Bodio C, Grossi C, Blengino S, Tincani A, Franceschini F, Andreoli L, Lazzaroni MG, Piantoni S, Masneri S, Crisafulli F, Brugnoni D, Muiesan ML, Salvetti M, Parati G, Torresani E, Mahler M, Heilbron F, Pregnolato F, Pengo M, Tedesco F, Pozzi N, Meroni PL. Anti-phospholipid antibodies in COVID-19 are different from those detectable in the anti-phospholipid syndrome. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2020. [PMID: 32588001 DOI: 10.1101/2020.06.17.20134114] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
BACKGROUND Critically ill patients with coronavirus disease 2019 (COVID-19) have a profound hypercoagulable state and often develop coagulopathy which leads to organ failure and death. Because of a prolonged activated partial-thromboplastin time (aPTT), a relationship with anti-phospholipid antibodies (aPL) has been proposed, but results are controversial. Functional assays for aPL (i.e., lupus anticoagulant) can be influenced by concomitant anticoagulation and/or high levels of C reactive protein. The presence of anti-cardiolipin (aCL), anti-beta2-glycoprotein I (anti-β2GPI) and anti-phosphatidylserine/prothrombin (aPS/PT) antibodies was not investigated systematically. Epitope specificity of anti-β2GPI antibodies was not reported. OBJECTIVE To evaluate the prevalence and the clinical association of aPL in a large cohort of COVID-19 patients, and to characterize the epitope specificity of anti-β2GPI antibodies. METHODS ELISA and chemiluminescence assays were used to test 122 sera of patients suffering from severe COVID-19. Of them, 16 displayed major thrombotic events. RESULTS Anti-β2GPI IgG/IgA/IgM were the most frequent in 15.6/6.6/9.0% of patients, while aCL IgG/IgM were detected in 5.7/6.6% by ELISA. Comparable values were found by chemiluminescence. aPS/PT IgG/IgM were detectable in 2.5 and 9.8% by ELISA. No association between thrombosis and aPL was found. Reactivity against domain 1 and 4-5 of β2GPI was limited to 3/58 (5.2%) tested sera for each domain and did not correlate with aCL/anti-β2GPI nor with thrombosis. CONCLUSIONS aPL show a low prevalence in COVID-19 patients and are not associated with major thrombotic events. aPL in COVID-19 patients are mainly directed against β2GPI but display an epitope specificity different from antibodies in antiphospholipid syndrome.
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