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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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2
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Liu X, Liu H, Deng Y. Efferocytosis: An Emerging Therapeutic Strategy for Type 2 Diabetes Mellitus and Diabetes Complications. J Inflamm Res 2023; 16:2801-2815. [PMID: 37440994 PMCID: PMC10335275 DOI: 10.2147/jir.s418334] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2023] [Accepted: 06/24/2023] [Indexed: 07/15/2023] Open
Abstract
Increasing evidence indicates that chronic, low-grade inflammation is a significant contributor to the fundamental pathogenesis of type 2 diabetes mellitus (T2DM). Efferocytosis, an effective way to eliminate apoptotic cells (ACs), plays a critical role in inflammation resolution. Massive accumulation of ACs and the proliferation of persistent inflammation caused by defective efferocytosis have been proven to be closely associated with pancreatic islet β cell destruction, adipose tissue inflammation, skeletal muscle dysfunction, and liver metabolism abnormalities, which together are considered the most fundamental pathological mechanism underlying T2DM. Therefore, here we outline the association between the molecular mechanisms of efferocytosis in glucose homeostasis, T2DM, and its complications, and we analyzed the present constraints and potential future prospects for therapeutic targets in T2DM and its complications.
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Affiliation(s)
- Xun Liu
- Hunan University of Chinese Medicine, Changsha, Hunan, 410208, People’s Republic of China
| | - Hua Liu
- Southern Theater General Hospital of the Chinese People’s Liberation Army, Guangzhou, Guangdong, 510010, People’s Republic of China
| | - Yihui Deng
- Hunan University of Chinese Medicine, Changsha, Hunan, 410208, People’s Republic of China
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3
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Álvarez D, Morales-Prieto DM, Cadavid ÁP. Interaction between endothelial cell-derived extracellular vesicles and monocytes: A potential link between vascular thrombosis and pregnancy-related morbidity in antiphospholipid syndrome. Autoimmun Rev 2023; 22:103274. [PMID: 36649876 DOI: 10.1016/j.autrev.2023.103274] [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: 12/23/2022] [Accepted: 01/12/2023] [Indexed: 01/15/2023]
Abstract
Antiphospholipid syndrome (APS) is an autoimmune disease driven by a wide group of autoantibodies primarily directed against phospholipid-binding proteins (antiphospholipid antibodies). APS is defined by two main kinds of clinical manifestations: vascular thrombosis and pregnancy-related morbidity. In recent years, in vitro and in vivo assays, as well as the study of large groups of patients with APS, have led some authors to suggest that obstetric and vascular manifestations of the disease are probably the result of different pathogenic mechanisms. According to this hypothesis, the disease could be differentiated into two parallel entities: Vascular APS and obstetric APS. Thus, vascular APS is understood as an acquired thrombophilia in which a generalised phenomenon of endothelial activation and dysfunction (coupled with a triggering factor) causes thrombosis at any location. In contrast, obstetric APS seems to be due to an inflammatory phenomenon accompanied by trophoblast cell dysfunction. The recent approach to APS raises new issues; for instance, the mechanisms by which a single set of autoantibodies can lead to two different clinical entities are unclear. This review will address the monocyte, a cell with well-known roles in haemostasis and pregnancy, as a potential participant in vascular thrombosis and pregnancy-related morbidity in APS. We will discuss how in a steady state the monocyte-endothelial interaction occurs via extracellular vesicles (EVs), and how antiphospholipid antibodies, by inducing endothelial activation and dysfunction, may disturb this interaction to promote the release of monocyte-targeted procoagulant and inflammatory messages.
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Affiliation(s)
- Daniel Álvarez
- Grupo Reproducción, Departamento Microbiología y Parasitología, Facultad de Medicina, Universidad de Antioquia UdeA, Calle 70 No. 52-21, Medellín, Colombia.
| | - Diana M Morales-Prieto
- Placenta Lab, Department of Obstetrics, Jena University Hospital, Am Klinikum 1, 07747 Jena, Germany.
| | - Ángela P Cadavid
- Grupo Reproducción, Departamento Microbiología y Parasitología, Facultad de Medicina, Universidad de Antioquia UdeA, Calle 70 No. 52-21, Medellín, Colombia; Grupo de Investigación en Trombosis, Departamento Medicina Interna, Facultad de Medicina, Universidad de Antioquia UdeA, Medellín, Colombia.
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4
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Grossi C, Capitani N, Benagiano M, Baldari CT, Della Bella C, Macor P, Tedesco F, Borghi MO, Maugeri N, D’Elios MM, Meroni PL. Beta 2 glycoprotein I and neutrophil extracellular traps: Potential bridge between innate and adaptive immunity in anti-phospholipid syndrome. Front Immunol 2023; 13:1076167. [PMID: 36700193 PMCID: PMC9868732 DOI: 10.3389/fimmu.2022.1076167] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Accepted: 12/20/2022] [Indexed: 01/10/2023] Open
Abstract
Antiphospholipid syndrome (APS) is a systemic autoimmune disorder characterized by recurrent vascular thrombosis and miscarriages in the absence of known causes. Antibodies against phospholipid-binding proteins (aPL) are pathogenic players in both clotting and pregnancy APS manifestations. There is sound evidence that antibodies specific for beta2 glycoprotein I (β2GPI) trigger thrombotic and pregnancy complications by interacting with the molecule on the membranes of different cell types of the coagulation cascade, and in placenta tissues. In addition to the humoral response against β2GPI, both peripheral and tissue CD4+ β2GPI-specific T cells have been reported in primary APS as well as in systemic lupus erythematosus (SLE)-associated APS. While adaptive immunity plays a clear role in APS, it is still debated whether innate immunity is involved as well. Acute systemic inflammation does not seem to be present in the syndrome, however, there is sound evidence that complement activation is crucial in animal models and can be found also in patients. Furthermore, neutrophil extracellular traps (NETs) have been documented in arterial and venous thrombi with different etiology, including clots in APS models. Keeping in mind that β2GPI is a pleiotropic glycoprotein, acting as scavenger molecule for infectious agents and apoptotic/damaged body constituents and that self-molecules externalized through NETs formation may become immunogenic autoantigens, we demonstrated β2GPI on NETs, and its ability to stimulate CD4+β2GPI-specific T cells. The aim of this review is to elucidate the role of β2GPI in the cross-talk between the innate and adaptive immunity in APS.
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Affiliation(s)
- Claudia Grossi
- Istituto Auxologico Italiano, Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS), Laboratory of Immuno-Rheumatology, Milan, Italy
| | - Nagaja Capitani
- Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy,Department of Life Sciences, University of Siena, Siena, Italy
| | - Marisa Benagiano
- Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy
| | | | - Chiara Della Bella
- Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy
| | - Paolo Macor
- Department of Life Science, University of Trieste, Trieste, Italy
| | - Francesco Tedesco
- Istituto Auxologico Italiano, Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS), Laboratory of Immuno-Rheumatology, Milan, Italy
| | - Maria Orietta Borghi
- Istituto Auxologico Italiano, Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS), Laboratory of Immuno-Rheumatology, Milan, Italy,Department of Clinical Science and Community Health, University of Milan, Milan, Italy
| | - Norma Maugeri
- Autoimmunity and Vascular Inflammation Unit, Division of Immunology, Transplantation & Infectious Diseases, Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) San Raffaele Institute, Milan, Italy
| | - Mario Milco D’Elios
- Department of Molecular and Developmental Medicine, University of Siena, Siena, Italy,*Correspondence: Pier Luigi Meroni, ; ; Mario Milco D’Elios,
| | - Pier Luigi Meroni
- Istituto Auxologico Italiano, Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS), Laboratory of Immuno-Rheumatology, Milan, Italy,*Correspondence: Pier Luigi Meroni, ; ; Mario Milco D’Elios,
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5
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Zhang J, Ding W, Zhao M, Liu J, Xu Y, Wan J, Wang M. Mechanisms of efferocytosis in determining inflammation resolution: Therapeutic potential and the association with cardiovascular disease. Br J Pharmacol 2022; 179:5151-5171. [PMID: 36028471 DOI: 10.1111/bph.15939] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Revised: 08/16/2022] [Accepted: 08/19/2022] [Indexed: 11/29/2022] Open
Abstract
Efferocytosis is defined as the clearance of apoptotic cells (ACs) in physiological and pathological states and is performed by efferocytes, such as macrophages. Efferocytosis can lead to the resolution of inflammation and restore tissue homoeostasis; however, the mechanisms of efferocytosis in determining inflammation resolution are still not completely understood, and the effects of efferocytosis on other proresolving properties need to be explored and explained. In this review, the process of efferocytosis will be summarized briefly, and then these mechanisms and effects will be thoroughly discussed. In addition, the association between the mechanisms of efferocytosis in determining inflammation resolution and cardiovascular diseases will also be reviewed, as an understanding of this association may provide information on novel treatment targets.
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Affiliation(s)
- Jishou Zhang
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, China.,Cardiovascular Research Institute, Wuhan University, Wuhan, China.,Hubei Key Laboratory of Cardiology, Wuhan, China
| | - Wen Ding
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, China.,Cardiovascular Research Institute, Wuhan University, Wuhan, China.,Hubei Key Laboratory of Cardiology, Wuhan, China.,department of radiology, the First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China
| | - Mengmeng Zhao
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, China.,Cardiovascular Research Institute, Wuhan University, Wuhan, China.,Hubei Key Laboratory of Cardiology, Wuhan, China
| | - Jianfang Liu
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, China.,Cardiovascular Research Institute, Wuhan University, Wuhan, China.,Hubei Key Laboratory of Cardiology, Wuhan, China
| | - Yao Xu
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, China.,Cardiovascular Research Institute, Wuhan University, Wuhan, China.,Hubei Key Laboratory of Cardiology, Wuhan, China
| | - Jun Wan
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, China.,Cardiovascular Research Institute, Wuhan University, Wuhan, China.,Hubei Key Laboratory of Cardiology, Wuhan, China
| | - Menglong Wang
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, China.,Cardiovascular Research Institute, Wuhan University, Wuhan, China.,Hubei Key Laboratory of Cardiology, Wuhan, China
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6
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Boteanu RM, Suica VI, Uyy E, Ivan L, Cerveanu-Hogas A, Mares RG, Simionescu M, Schiopu A, Antohe F. Short-Term Blockade of Pro-Inflammatory Alarmin S100A9 Favorably Modulates Left Ventricle Proteome and Related Signaling Pathways Involved in Post-Myocardial Infarction Recovery. Int J Mol Sci 2022; 23:ijms23095289. [PMID: 35563680 PMCID: PMC9103348 DOI: 10.3390/ijms23095289] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Revised: 05/05/2022] [Accepted: 05/08/2022] [Indexed: 02/01/2023] Open
Abstract
Prognosis after myocardial infarction (MI) varies greatly depending on the extent of damaged area and the management of biological processes during recovery. Reportedly, the inhibition of the pro-inflammatory S100A9 reduces myocardial damage after MI. We hypothesize that a S100A9 blockade induces changes of major signaling pathways implicated in post-MI healing. Mass spectrometry-based proteomics and gene analyses of infarcted mice left ventricle were performed. The S100A9 blocker (ABR-23890) was given for 3 days after coronary ligation. At 3 and 7 days post-MI, ventricle samples were analyzed versus control and Sham-operated mice. Blockade of S100A9 modulated the expressed proteins involved in five biological processes: leukocyte cell–cell adhesion, regulation of the muscle cell apoptotic process, regulation of the intrinsic apoptotic signaling pathway, sarcomere organization and cardiac muscle hypertrophy. The blocker induced regulation of 36 proteins interacting with or targeted by the cellular tumor antigen p53, prevented myocardial compensatory hypertrophy, and reduced cardiac markers of post-ischemic stress. The blockade effect was prominent at day 7 post-MI when the quantitative features of the ventricle proteome were closer to controls. Blockade of S100A9 restores key biological processes altered post-MI. These processes could be valuable new pharmacological targets for the treatment of ischemic heart. Mass spectrometry data are available via ProteomeXchange with identifier PXD033683.
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Affiliation(s)
- Raluca Maria Boteanu
- Department of Proteomics, Institute of Cellular Biology and Pathology “N. Simionescu” of the Romanian Academy, 050568 Bucharest, Romania; (R.M.B.); (V.-I.S.); (E.U.); (L.I.); (A.C.-H.); (M.S.)
| | - Viorel-Iulian Suica
- Department of Proteomics, Institute of Cellular Biology and Pathology “N. Simionescu” of the Romanian Academy, 050568 Bucharest, Romania; (R.M.B.); (V.-I.S.); (E.U.); (L.I.); (A.C.-H.); (M.S.)
| | - Elena Uyy
- Department of Proteomics, Institute of Cellular Biology and Pathology “N. Simionescu” of the Romanian Academy, 050568 Bucharest, Romania; (R.M.B.); (V.-I.S.); (E.U.); (L.I.); (A.C.-H.); (M.S.)
| | - Luminita Ivan
- Department of Proteomics, Institute of Cellular Biology and Pathology “N. Simionescu” of the Romanian Academy, 050568 Bucharest, Romania; (R.M.B.); (V.-I.S.); (E.U.); (L.I.); (A.C.-H.); (M.S.)
| | - Aurel Cerveanu-Hogas
- Department of Proteomics, Institute of Cellular Biology and Pathology “N. Simionescu” of the Romanian Academy, 050568 Bucharest, Romania; (R.M.B.); (V.-I.S.); (E.U.); (L.I.); (A.C.-H.); (M.S.)
| | - Razvan Gheorghita Mares
- Department of Pathophysiology, University of Medicine, Pharmacy, Sciences and Technology of Targu Mures, 540142 Targu Mures, Romania; (R.G.M.); (A.S.)
| | - Maya Simionescu
- Department of Proteomics, Institute of Cellular Biology and Pathology “N. Simionescu” of the Romanian Academy, 050568 Bucharest, Romania; (R.M.B.); (V.-I.S.); (E.U.); (L.I.); (A.C.-H.); (M.S.)
| | - Alexandru Schiopu
- Department of Pathophysiology, University of Medicine, Pharmacy, Sciences and Technology of Targu Mures, 540142 Targu Mures, Romania; (R.G.M.); (A.S.)
- Department of Clinical Sciences Malmö, Lund University, 21428 Malmö, Sweden
| | - Felicia Antohe
- Department of Proteomics, Institute of Cellular Biology and Pathology “N. Simionescu” of the Romanian Academy, 050568 Bucharest, Romania; (R.M.B.); (V.-I.S.); (E.U.); (L.I.); (A.C.-H.); (M.S.)
- Correspondence: ; Tel.: +40-213-192-737
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7
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Serrano M, Espinosa G, Serrano A, Cervera R. Antigens and Antibodies of the Antiphospholipid Syndrome as New Allies in the Pathogenesis of COVID-19 Coagulopathy. Int J Mol Sci 2022; 23:ijms23094946. [PMID: 35563337 PMCID: PMC9102661 DOI: 10.3390/ijms23094946] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2022] [Revised: 04/21/2022] [Accepted: 04/26/2022] [Indexed: 01/27/2023] Open
Abstract
High prevalence of both criteria and extra-criteria antiphospholipid antibodies (aPL) has been reported in COVID-19 patients. However, the differences in aPL prevalence decreased when an age-matched control group was included. The association of aPL with thrombotic events in COVID-19 is very heterogeneous. This could be influenced by the fact that most of the studies carried out were conducted on small populations enriched with elderly patients in which aPL was measured only at a single point and they were performed with non-standardized assays. The few studies that confirmed aPL in a second measurement showed that aPL levels hardly changed, with the exception of the lupus anticoagulant that commonly reduced. COVID-19 coagulopathy is an aPL-independent phenomenon closely associated with the onset of the disease. Thrombosis occurs later in patients with aPL presence, which is likely an additional prothrombotic factor. B2-glycoprotein deficiency (mainly aPL antigen caused both by low production and consumption) is very common during the SARS-CoV2 infection and has been associated with a greater predisposition to COVID-19 complications. This could be a new prothrombotic mechanism that may be caused by the blockage of its physiological functions, the anticoagulant state being the most important.
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Affiliation(s)
- Manuel Serrano
- Department of Immunology, Healthcare Research Institute I+12, Hospital 12 de Octubre, 28041 Madrid, Spain;
| | - Gerard Espinosa
- Department of Autoimmune Diseases, Hospital Clínic, Insititut d’Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Universitat de Barcelona, 08036 Barcelona, Spain; (G.E.); (R.C.)
| | - Antonio Serrano
- Department of Immunology, Healthcare Research Institute I+12, Hospital 12 de Octubre, 28041 Madrid, Spain;
- Correspondence: or
| | - Ricard Cervera
- Department of Autoimmune Diseases, Hospital Clínic, Insititut d’Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Universitat de Barcelona, 08036 Barcelona, Spain; (G.E.); (R.C.)
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8
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Linge CP, Jern A, Tydén H, Gullstrand B, Yan H, Welinder C, Kahn R, Jönssen A, Semple JW, Bengtsson AA. Enrichment of complement, immunoglobulins and autoantibody targets in the proteome of platelets from patients with Systemic Lupus Erythematosus (SLE). Thromb Haemost 2022; 122:1486-1501. [PMID: 35419777 PMCID: PMC9420555 DOI: 10.1055/a-1825-2915] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Background
Systemic lupus erythematosus (SLE) is a complex disease characterized by autoimmunity toward apoptotic cells, excessive amounts of circulating immune complexes, and complement activation. A decreased platelet size has been observed in SLE and their nonhemostatic functions may play an active role in the disease. The main objective of this study was to find clues that could explain their decreased size and functional role, analyzing the entire platelet proteome.
Methods
Platelets were isolated from 23 patients with SLE. The five individuals with the highest and lowest average platelet forward scatter were selected for further analysis. Platelet protein content was analyzed using liquid chromatography with tandem mass spectrometry (LC-MS/MS) and compared with platelets from five healthy controls. Data are available via ProteomeXchange with identifier PXD031202.
Results
Out of 2,572 proteins identified, 396 had significantly different levels (ANOVA
q
-value ≤ 0.01). Forty proteins, including immunoglobulin-, complement- and phosphatidylserine-binding proteins had higher abundance in platelets from SLE patients, largely independent of size (fold difference of ≥1.5 and a
t
-test
p
-value of ≤0.05 as cut-off). Functional characterization revealed increased degranulation and skewed hemostatic balance in platelets from SLE patients. In the SLE proteome, immunoglobulin proteins were negatively correlated to serum complement C3 and C4 and the highest relative levels were detected in platelets of normal size.
Conclusion
Platelets from SLE patients shared a specific protein profile, including immunoglobulins, complement proteins, and autoantigens, largely independent of the platelet size and in agreement with an integrated role for platelets in SLE.
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Affiliation(s)
- Carl Petrus Linge
- Department of Clinical Sciences Lund, Lund University Section for Molecular Skeletal Biology and Rheumatology, Lund, Sweden
| | - Andreas Jern
- Department of Clinical Sciences, Lund University Section for Molecular Skeletal Biology and Rheumatology, Lund, Sweden
| | - Helena Tydén
- Department of Clinical Sciences, Lund University Section for Molecular Skeletal Biology and Rheumatology, Lund, Sweden
| | - Birgitta Gullstrand
- Department of Clinical Sciences, Lund University Section for Molecular Skeletal Biology and Rheumatology, Lund, Sweden
| | - Hong Yan
- BioMS, Swedish National Infrastructure for Biological Mass Spectrometry, Lund, Sweden
| | - Charlotte Welinder
- Department of Clinical Sciences Lund, Lund University Department of Oncology and Pathology, Lund, Sweden
| | - Robin Kahn
- Wallenberg Center for Molecular Medicin, Lund University Faculty of Medicine, Lund, Sweden.,Paediatrics, Lund University Faculty of Medicine, Lund, Sweden
| | - Andreas Jönssen
- Department of Clinical Sciences Lund, Lund University Section for Molecular Skeletal Biology and Rheumatology, Lund, Sweden
| | - John W Semple
- Transfusion Medicine, Lunds Universitet, Lund, Sweden
| | - Anders A Bengtsson
- Department of Clinical Sciences, Lund University Section for Molecular Skeletal Biology and Rheumatology, Lund, Sweden
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9
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Cabrera JTO, Makino A. Efferocytosis of vascular cells in cardiovascular disease. Pharmacol Ther 2022; 229:107919. [PMID: 34171333 PMCID: PMC8695637 DOI: 10.1016/j.pharmthera.2021.107919] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Revised: 05/21/2021] [Accepted: 06/03/2021] [Indexed: 12/20/2022]
Abstract
Cell death and the clearance of apoptotic cells are tightly regulated by various signaling molecules in order to maintain physiological tissue function and homeostasis. The phagocytic removal of apoptotic cells is known as the process of efferocytosis, and abnormal efferocytosis is linked to various health complications and diseases, such as cardiovascular disease, inflammatory diseases, and autoimmune diseases. During efferocytosis, phagocytic cells and/or apoptotic cells release signals, such as "find me" and "eat me" signals, to stimulate the phagocytic engulfment of apoptotic cells. Primary phagocytic cells are macrophages and dendritic cells; however, more recently, other neighboring cell types have also been shown to exhibit phagocytic character, including endothelial cells and fibroblasts, although they are comparatively slower in clearing dead cells. In this review, we focus on macrophage efferocytosis of vascular cells, such as endothelial cells, smooth muscle cells, fibroblasts, and pericytes, and its relation to the progression and development of cardiovascular disease. We also highlight the role of efferocytosis-related molecules and their contribution to the maintenance of vascular homeostasis.
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Affiliation(s)
- Jody Tori O Cabrera
- Division of Endocrinology and Metabolism, Department of Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Ayako Makino
- Division of Endocrinology and Metabolism, Department of Medicine, University of California, San Diego, La Jolla, CA, USA.
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10
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Grossi C, Artusi C, Meroni P, Borghi MO, Neglia L, Lonati PA, Oggioni M, Tedesco F, De Simoni MG, Fumagalli S. β2 glycoprotein I participates in phagocytosis of apoptotic neurons and in vascular injury in experimental brain stroke. J Cereb Blood Flow Metab 2021; 41:2038-2053. [PMID: 33444093 PMCID: PMC8323337 DOI: 10.1177/0271678x20984551] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Beta-2 Glycoprotein I (β2-GPI) is the main target of anti-phospholipid antibodies (aPL) in the autoimmune anti-phospholipid syndrome, characterized by increased risk of stroke. We here investigated the antibody independent role of β2-GPI after ischemia/reperfusion, modeled in vivo by transient middle cerebral artery occlusion (tMCAo) in male C57Bl/6J mice; in vitro by subjecting immortalized human brain microvascular endothelial cells (ihBMEC) to 16 h hypoxia and 4 h re-oxygenation. ApoH (coding for β2-GPI) was upregulated selectively in the liver at 48 h after tMCAo. At the same time β2-GPI circulating levels increased. β2-GPI was detectable in brain parenchyma and endothelium at all time points after tMCAo. Parenchymal β2-GPI recognized apoptotic neurons (positive for annexin V, C3 and TUNEL) cleared by CD68+ brain macrophages. Hypoxic ihBMEC showed increased release of IL-6, over-expression of thrombomodulin and IL-1α after re-oxygenation with β2-GPI alone. β2-GPI interacted with mannose-binding lectin in mouse plasma and ihBMEC medium, potentially involved in formation of thrombi. We show for the first time that brain ischemia triggers the hepatic production of β2-GPI. β2-GPI is present in the ischemic endothelium, enhancing vascular inflammation, and extravasates binding stressed neurons before their clearance by phagocytosis. Thus β2-GPI may be a new mediator of brain injury following ischemic stroke.
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Affiliation(s)
- Claudia Grossi
- Istituto Auxologico Italiano, IRCCS, Laboratory of Immuno-Rheumatology, Milan, Italy
| | - Carolina Artusi
- Rheumatology Department, ASST Gaetano Pini-CTO, Milan, Italy.,Department of Clinical Sciences and Community Health, University of Milan, Milan, Italy
| | - PierLuigi Meroni
- Istituto Auxologico Italiano, IRCCS, Laboratory of Immuno-Rheumatology, Milan, Italy
| | - Maria Orietta Borghi
- Istituto Auxologico Italiano, IRCCS, Laboratory of Immuno-Rheumatology, Milan, Italy.,Department of Clinical Sciences and Community Health, University of Milan, Milan, Italy
| | - Laura Neglia
- Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Department of Neuroscience, Milan, Italy
| | - Paola Adele Lonati
- Istituto Auxologico Italiano, IRCCS, Laboratory of Immuno-Rheumatology, Milan, Italy
| | - Marco Oggioni
- Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Department of Neuroscience, Milan, Italy
| | - Francesco Tedesco
- Istituto Auxologico Italiano, IRCCS, Laboratory of Immuno-Rheumatology, Milan, Italy
| | - Maria-Grazia De Simoni
- Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Department of Neuroscience, Milan, Italy
| | - Stefano Fumagalli
- Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Department of Neuroscience, Milan, Italy
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Cecchi I, Radin M, Rodríguez-Carrio J, Tambralli A, Knight JS, Sciascia S. Utilizing type I interferon expression in the identification of antiphospholipid syndrome subsets. Expert Rev Clin Immunol 2021; 17:395-406. [PMID: 33686921 PMCID: PMC10183148 DOI: 10.1080/1744666x.2021.1901581] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
INTRODUCTION Antiphospholipid Syndrome (APS) is a systemic autoimmune disease with a complex multifactorial pathogenesis, combining genetic background, traditional cardiovascular risk factors, disease-specific features such as the presence of antiphospholipid antibodies (aPL), and an imbalance of various immune system functions. Recent data support the role of interferons (IFNs), especially type IIFN (IFN-I), in the onset and development of APS clinical manifestations, including thrombotic events and obstetric complications. AREAS COVERED In this review, the authors aimed to discuss the growing body of evidence on the relevance of IFN-I pathways in APS, both from a basic mechanistic perspective, focusing on its possible use in disease/patients stratification. The IFN-I signature has shown promising, although preliminary, results in segregating aPL-positive subjects by aPL profile, association with other autoimmune conditions, such as lupus, age at onset, and current treatment, among others. EXPERT OPINION To date, the scarce available data as well as methodological and technical heterogeneity among studies limit the comparability of the results, thus requiring further validation to translate these findings to routine clinical practice. Therefore, further research is required in pursuit of more nuanced patient profiling and the development of new immunomodulatory therapeutic strategies for APS beyond anti-coagulant and antiplatelet agents.
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Affiliation(s)
- Irene Cecchi
- Center of Research of Immunopathology and Rare Diseases - Nephrology and Dialysis Coordinating Center of Piemonte and Aosta Valley Network for Rare Diseases, S. Giovanni Bosco Hospital, Department of Clinical and Biological Sciences, University of Turin, Turin Italy
| | - Massimo Radin
- Center of Research of Immunopathology and Rare Diseases - Nephrology and Dialysis Coordinating Center of Piemonte and Aosta Valley Network for Rare Diseases, S. Giovanni Bosco Hospital, Department of Clinical and Biological Sciences, University of Turin, Turin Italy
| | - Javier Rodríguez-Carrio
- Department of Functional Biology, Immunology Area, Faculty of Medicine, University of Oviedo, Oviedo, Spain.,Group of Basic and Translational Research in Inflammatory Diseases, Instituto De Investigación Sanitaria Del Principado De Asturias (ISPA), Oviedo, Spain
| | - Ajay Tambralli
- Division of Rheumatology, University of Michigan, Ann Arbor, Michigan, USA
| | - Jason S Knight
- Division of Rheumatology, University of Michigan, Ann Arbor, Michigan, USA
| | - Savino Sciascia
- Center of Research of Immunopathology and Rare Diseases - Nephrology and Dialysis Coordinating Center of Piemonte and Aosta Valley Network for Rare Diseases, S. Giovanni Bosco Hospital, Department of Clinical and Biological Sciences, University of Turin, Turin Italy
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12
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Serrano M, Espinosa G, Lalueza A, Bravo-Gallego LY, Diaz-Simón R, Garcinuño S, Gil-Etayo J, Moises J, Naranjo L, Prieto-González S, Ruiz-Ortiz E, Sánchez B, Moreno-Castaño AB, Díaz-Pedroche C, Viñas-Gomis O, Cervera R, Serrano A. Beta-2-Glycoprotein-I Deficiency Could Precipitate an Antiphospholipid Syndrome-like Prothrombotic Situation in Patients With Coronavirus Disease 2019. ACR Open Rheumatol 2021; 3:267-276. [PMID: 33738987 PMCID: PMC8063141 DOI: 10.1002/acr2.11245] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2020] [Accepted: 02/09/2021] [Indexed: 12/13/2022] Open
Abstract
Objective Patients with coronavirus disease 2019 (COVID‐19) present coagulation abnormalities and thromboembolic events that resemble antiphospholipid syndrome (APS). This work has aimed to study the prevalence of APS‐related antigens, antibodies, and immune complexes in patients with COVID‐19 and their association with clinical events. Methods A prospective study was conducted on 474 adults with severe acute respiratory syndrome coronavirus 2 infection hospitalized in two Spanish university hospitals. Patients were evaluated for classic and extra‐criteria antiphospholipid antibodies (aPLs), immunoglobulin G (IgG)/immunoglobulin M (IgM) anticardiolipin, IgG/IgM/immunoglobulin A (IgA) anti‐β2‐glicoprotein‐I (aβ2GPI), IgG/IgM antiphosphatidylserine/prothrombin (aPS/PT), the immune complex of IgA aβ2GPI (IgA‐aβ2GPI), bounded to β2‐glicoprotein‐1 (β2GPI) and β2GPI levels soon after COVID‐19 diagnosis and were followed‐up until medical discharge or death. Results Prevalence of aPLs in patients with COVID‐19 was as follows: classic aPLs, 5.8%; aPS/PT, 4.6%; IgA‐aβ2GPI, 15%; and any aPL, 21%. When patients were compared with individuals of a control group of a similar age, the only significant difference found was the higher prevalence of IgA‐aβ2GPI (odds ratio: 2.31; 95% confidence interval: 1.16‐4.09). No significant differences were observed in survival, thrombosis, or ventilatory failure in aPL‐positive versus aPL‐negative patients. β2GPI median levels were much lower in patients with COVID‐19 (15.9 mg/l) than in blood donors (168.8 mg/l; P < 0.001). Only 3.5% of patients with COVID‐19 had normal levels of β2GPI (>85 mg/l). Low levels of β2GPI were significantly associated with ventilatory failure (P = 0.026). Conclusion β2GPI levels were much lower in patients with COVID‐19 than in healthy people. Low β2GPI‐levels were associated with ventilatory failure. No differences were observed in the COVID‐19 evolution between aPL‐positive and aPL‐negative patients. Functional β2GPI deficiency could trigger a clinical process similar to that seen in APS but in the absence of aPLs.
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Affiliation(s)
- Manuel Serrano
- Hospital 12 de Octubre, Healthcare Research Institute and Hospital Clínico San Carlos, Madrid, Spain
| | - Gerard Espinosa
- Hospital Clínic, Institut d'Investigacions Biomèdiques August Pi i Sunyer, University of Barcelona, Barcelona, Catalonia, Spain
| | - Antonio Lalueza
- Hospital 12 de Octubre, Healthcare Research Institute I+12, Madrid, Spain
| | - Luz Yadira Bravo-Gallego
- Hospital Clínic, Institut d'Investigacions Biomèdiques August Pi i Sunyer, University of Barcelona, Barcelona, Catalonia, Spain
| | - Raquel Diaz-Simón
- Hospital 12 de Octubre, Healthcare Research Institute I+12, Madrid, Spain
| | - Sara Garcinuño
- Hospital 12 de Octubre, Healthcare Research Institute I+12, Madrid, Spain
| | - Javier Gil-Etayo
- Hospital 12 de Octubre, Healthcare Research Institute I+12, Madrid, Spain
| | - Jorge Moises
- Hospital Clínic, Institut d'Investigacions Biomèdiques August Pi i Sunyer, University of Barcelona, Barcelona, Catalonia, Spain
| | - Laura Naranjo
- Hospital 12 de Octubre, Healthcare Research Institute I+12, Madrid, Spain
| | - Sergio Prieto-González
- Hospital Clínic, Institut d'Investigacions Biomèdiques August Pi i Sunyer, University of Barcelona, Barcelona, Catalonia, Spain
| | - Estibaliz Ruiz-Ortiz
- Hospital Clínic, Institut d'Investigacions Biomèdiques August Pi i Sunyer, University of Barcelona, Barcelona, Catalonia, Spain
| | - Beatriz Sánchez
- Hospital Clínic, Institut d'Investigacions Biomèdiques August Pi i Sunyer, University of Barcelona, Barcelona, Catalonia, Spain
| | - Ana Belen Moreno-Castaño
- Hospital Clínic, Institut d'Investigacions Biomèdiques August Pi i Sunyer, University of Barcelona, Barcelona, Catalonia, Spain
| | | | - Odette Viñas-Gomis
- Hospital Clínic, Institut d'Investigacions Biomèdiques August Pi i Sunyer, University of Barcelona, Barcelona, Catalonia, Spain
| | - Ricard Cervera
- Hospital Clínic, Institut d'Investigacions Biomèdiques August Pi i Sunyer, University of Barcelona, Barcelona, Catalonia, Spain
| | - Antonio Serrano
- Hospital 12 de Octubre, Healthcare Research Institute and Biomedical Research Centre Network for Epidemiology and Public Health, Madrid, Spain
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13
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The Weight of IgA Anti-β2glycoprotein I in the Antiphospholipid Syndrome Pathogenesis: Closing the Gap of Seronegative Antiphospholipid Syndrome. Int J Mol Sci 2020; 21:ijms21238972. [PMID: 33255963 PMCID: PMC7730063 DOI: 10.3390/ijms21238972] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 11/20/2020] [Accepted: 11/23/2020] [Indexed: 12/12/2022] Open
Abstract
The specific value of IgA Anti-β2glycoprotein I antibodies (aB2GP1) in the diagnosis and management of antiphospholipid syndrome (APS) is still controversial and a matter of active debate. The relevance of the IgA aB2GP1 isotype in the pathophysiology of APS has been increasingly studied in the last years. There is well know that subjects with multiple positive APS tests are at increased risk of thrombosis and/or miscarriage. However, these antibodies are not included in the 2006 APS classification criteria. Since 2010 the task force of the Galveston International Congress on APS recommends testing IgA aB2GP1 isotype in patients with APS clinical criteria in the absence of criteria antibodies. In this review, we summarize the molecular and clinical “state of the art” of the IgA aB2GP in the context of APS. We also discuss some of the characteristics that may help to evaluate the real value of the IgA aB2GP1 determination in basic research and clinical practice. The scientific community should be aware of the importance of clarifying the role of IgA aB2GP1 in the APS diagnosis.
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Fang YY, Zhang JH. MFG-E8 alleviates oxygen-glucose deprivation-induced neuronal cell apoptosis by STAT3 regulating the selective polarization of microglia. Int J Neurosci 2020; 131:15-24. [PMID: 32098538 DOI: 10.1080/00207454.2020.1732971] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Background: Ischemic stroke is a complex pathological process, involving inflammatory reaction, energy metabolism disorder, free radical injury, cell apoptosis and other aspects. Accumulating evidences have revealed that MFG-E8 had a protective effect on multiple organ injuries. However, the comprehensive function and mechanism of MFG-E8 in ischemic brain remain largely unclear.Methods: BV-2 cells were treated with recombinant murine MFG-E8 (rmMFG-E8) or/and Colivelin TFA after exposing for 4 h with oxygen glucose deprivation (OGD). Cell viability and apoptosis were assessed by MTT assay and Flow cytometry. RT-qPCR and Western blot assays were applied to examine the expression levels of MFG-E8, apoptosis-related proteins and M1/M2 polarization markers.Results: Our results demonstrated that OGD significantly inhibited microglial viability and facilitated apoptosis. In addition, we found that OGD downregulated MFG-E8 expression, and MFG-E8 inhibited OGD-induced microglial apoptosis and promoted microglial M2 polarization. In terms of mechanism, we proved that MFG-E8 regulated OGD-induced microglial M1/M2 polarization by inhibiting p-STAT3 and SOCS3 expressions, which was reversed by STAT3 activator (Colivelin TFA). Finally, we verified MFG-E8 alleviated OGD-induced neuronal cell apoptosis by M2 polarization of BV-2 cells.Conclusions: We demonstrated that MFG-E8 reduced neuronal cell apoptosis by enhancing activation of microglia via STAT3 signaling. Therefore, we suggested that MFG-E8 might provide a novel mechanism for ischemic stroke.
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Affiliation(s)
- Ying-Ying Fang
- Department of Neurobiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, Guangdong Province, P.R. China
| | - Jing-Hui Zhang
- Department of Rehabilitation, The Third Affiliated Hospital of Sun Yat-Sen University, Guangzhou, Guangdong Province, P.R. China.,Guangdong Association of Rehabilitation Medicine, The Third Affiliated Hospital of Sun Yat-Sen University, Guangzhou, Guangdong Province, P.R. China
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15
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Ricks TJ, Cassilly CD, Carr AJ, Alves DS, Alam S, Tscherch K, Yokley TW, Workman CE, Morrell-Falvey JL, Barrera FN, Reynolds TB, Best MD. Labeling of Phosphatidylinositol Lipid Products in Cells through Metabolic Engineering by Using a Clickable myo-Inositol Probe. Chembiochem 2018; 20:172-180. [PMID: 30098105 DOI: 10.1002/cbic.201800248] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Revised: 07/30/2018] [Indexed: 12/28/2022]
Abstract
Phosphatidylinositol (PI) lipids control critical biological processes, so aberrant biosynthesis often leads to disease. As a result, the capability to track the production and localization of these compounds in cells is vital for elucidating their complex roles. Herein, we report the design, synthesis, and application of clickable myo-inositol probe 1 a for bioorthogonal labeling of PI products. To validate this platform, we initially conducted PI synthase assays to show that 1 a inhibits PI production in vitro. Fluorescence microscopy experiments next showed probe-dependent imaging in T-24 human bladder cancer and Candida albicans cells. Growth studies in the latter showed that replacement of myo-inositol with probe 1 a led to an enhancement in cell growth. Finally, fluorescence-based TLC analysis and mass spectrometry experiments support the labeling of PI lipids. This approach provides a promising means for tracking the complex biosynthesis and trafficking of these lipids in cells.
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Affiliation(s)
- Tanei J Ricks
- Department of Chemistry, University of Tennessee, 1420 Circle Park Drive, Knoxville, TN, 37996, USA
| | - Chelsi D Cassilly
- Department of Microbiology, University of Tennessee, 1414 Cumberland Avenue, Knoxville, TN, 37996-0840, USA
| | - Adam J Carr
- Department of Chemistry, University of Tennessee, 1420 Circle Park Drive, Knoxville, TN, 37996, USA
| | - Daiane S Alves
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, 1414 Cumberland Avenue, Knoxville, TN, 37996-0840, USA
| | - Shahrina Alam
- Department of Chemistry, University of Tennessee, 1420 Circle Park Drive, Knoxville, TN, 37996, USA
| | - Kathrin Tscherch
- Department of Chemistry, University of Tennessee, 1420 Circle Park Drive, Knoxville, TN, 37996, USA
| | - Timothy W Yokley
- Department of Chemistry, University of Tennessee, 1420 Circle Park Drive, Knoxville, TN, 37996, USA
| | - Cameron E Workman
- Department of Chemistry, University of Tennessee, 1420 Circle Park Drive, Knoxville, TN, 37996, USA
| | | | - Francisco N Barrera
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, 1414 Cumberland Avenue, Knoxville, TN, 37996-0840, USA
| | - Todd B Reynolds
- Department of Microbiology, University of Tennessee, 1414 Cumberland Avenue, Knoxville, TN, 37996-0840, USA
| | - Michael D Best
- Department of Chemistry, University of Tennessee, 1420 Circle Park Drive, Knoxville, TN, 37996, USA
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16
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Muhsin-Sharafaldine MR, McLellan AD. Tumor-Derived Apoptotic Vesicles: With Death They Do Part. Front Immunol 2018; 9:957. [PMID: 29780392 PMCID: PMC5952256 DOI: 10.3389/fimmu.2018.00957] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Accepted: 04/17/2018] [Indexed: 12/21/2022] Open
Abstract
Tumor cells release lipid particles known as extracellular vesicles (EV) that contribute to cancer metastasis, to the immune response, and to thrombosis. When tumors are exposed to radiation or chemotherapy, apoptotic vesicles (ApoVs) are released in abundance as the plasma membrane delaminates from the cytoskeleton. Recent studies have suggested that ApoVs are distinct from the EVs released from living cells, such as exosomes or microvesicles. Depending on their treatment conditions, tumor-released ApoV have been suggested to either enhance or suppress anti-cancer immunity. In addition, tumor-derived ApoV possess procoagulant activity that could increase the thrombotic state in cancer patients undergoing chemotherapy or radiotherapy. Since ApoVs are one of the least appreciated type of EVs, we focus in this review on the distinctive characterization of tumor ApoVs and their proposed mechanistic effects on cancer immunity, coagulation, and metastasis.
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Affiliation(s)
| | - Alexander D McLellan
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
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17
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Mobarrez F, Gunnarsson I, Svenungsson E. Altered β 2 -glycoprotein I expression on microparticles in the presence of antiphospholipid antibodies. J Thromb Haemost 2017; 15:1799-1806. [PMID: 28667788 DOI: 10.1111/jth.13765] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2017] [Accepted: 06/08/2017] [Indexed: 01/15/2023]
Abstract
Essentials β2 glycoprotein-I (β2 GPI) is a scavenger molecule that binds to microparticles (MPs). β2 GPI expression on MPs was measured in systemic lupus erythematosus (SLE) patients and controls. β2 GPI positive MPs is depressed among SLE patients positive for antiphospholipid antibodies. Complex formation between β2 GPI on MPs and patients own anti-β2 GPI may disturb MP clearance. Click to hear an ISTH Academy presentation on antiphospholipid antibody syndrome by Drs de Laat and Bertolaccini SUMMARY: Background Antiphospholipid antibodies (aPLs) together with thrombosis and/or pregnancy morbidities characterize the antiphospholipid syndrome. β2 -Glycoprotein I (β2 GPI), the most important antigen for aPLs, is a scavenger molecule that specifically binds to phosphatidylserine (PS) expressed on microparticles (MPs). Objectives To evaluate β2 GPI-expressing MPs in patients with systemic lupus erythematosus (SLE) stratified for aPL status, and in healthy controls. Patients/Methods We investigated 18 aPL/anti-β2 GPI-positive and 22 aPL-negative patients from a large SLE cohort and 19 healthy controls. β2 GPI-positive MPs and IgG-positive MPs were detected by flow cytometry. We measured plasma levels of β2 GPI, and performed in vitro experiments to investigate the binding properties of β2 GPI on MPs. Results SLE patients had more MPs and IgG-positive MPs than controls. We observed fewer β2 GPI-positive MPs in aPL/anti-β2 GPI-positive patients than in aPL/anti-β2 GPI-negative patients and controls (approximately two-fold). β2 GPI levels in plasma did not differ with aPL/anti-β2 GPI status in patients; however, controls had slightly higher levels of β2 GPI than aPL/anti-β2 GPI-positive patients. In vitro experiments revealed that β2 GPI preferentially binds to PS-positive MPs. Conclusions Despite abundant total MPs and MPs in immune complexes, β2 GPI-positive MPs were depleted in SLE patients, and the levels were especially low in aPL/anti-β2 GPI-positive patients. We suggest that anti-β2 GPI antibodies bind to β2 GPI-PS complexes expressed on MPs. Consequent loss of β2 GPI-PS expression on MPs may impair scavenging and contribute to the accumulation of circulating PS-negative MPs, a possible source of autoantigens. Autoantibodies delaying MP clearance may thus constitute an important mechanism underlying autoimmunity.
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Affiliation(s)
- F Mobarrez
- Unit of Rheumatology, Department of Medicine, Solna, Karolinska Institutet, Karolinska University Hospital, Stockholm, Sweden
| | - I Gunnarsson
- Unit of Rheumatology, Department of Medicine, Solna, Karolinska Institutet, Karolinska University Hospital, Stockholm, Sweden
| | - E Svenungsson
- Unit of Rheumatology, Department of Medicine, Solna, Karolinska Institutet, Karolinska University Hospital, Stockholm, Sweden
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18
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Abstract
Systemic lupus erythematosus (lupus, SLE) is a chronic autoimmune disease characterized by the production of autoantibodies, which bind to antigens and are deposited within tissues to fix complement, resulting in widespread systemic inflammation. The studies presented herein are consistent with hyperpolarized, adenosine triphosphate (ATP)-deficient mitochondria being central to the disease process. These hyperpolarized mitochondria resist the depolarization required for activation-induced apoptosis. The mitochondrial ATP deficits add to this resistance to apoptosis and also reduce the macrophage energy that is needed to clear apoptotic bodies. In both cases, necrosis, the alternative pathway of cell death, results. Intracellular constituents spill into the blood and tissues, eliciting inflammatory responses directed at their removal. What results is “autoimmunity.” Ultraviolet (UV)-A1 photons have the capacity to remediate this aberrancy. Exogenous exposure to low-dose, full-body, UV-A1 radiation generates singlet oxygen. Singlet oxygen has two major palliative actions in patients with lupus and the UV-A1 photons themselves have several more. Singlet oxygen depolarizes the hyperpolarized mitochondrion, triggering non-ATP-dependent apoptosis that deters necrosis. Next, singlet oxygen activates the gene encoding heme oxygenase (HO-1), a major governor of systemic homeostasis. HO-1 catalyzes the degradation of the oxidant heme into biliverdin (converted to bilirubin), Fe, and carbon monoxide (CO), the first three of these exerting powerful antioxidant effects, and in conjunction with a fourth, CO, protecting against injury to the coronary arteries, the central nervous system, and the lungs. The UV-A1 photons themselves directly attenuate disease in lupus by reducing B cell activity, preventing the suppression of cell-mediated immunity, slowing an epigenetic progression toward SLE, and ameliorating discoid and subacute cutaneous lupus. Finally, a combination of these mechanisms reduces levels of anticardiolipin antibodies and protects during lupus pregnancy. Capping all of this is that UV-A1 irradiation is an essentially innocuous, highly manageable, and comfortable therapeutic agency.
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Affiliation(s)
- H McGrath
- Veterans Administration, New Orleans, LA, USA
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19
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Arachchillage DRJ, Laffan M. Pathogenesis and management of antiphospholipid syndrome. Br J Haematol 2017; 178:181-195. [PMID: 28339096 DOI: 10.1111/bjh.14632] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Antiphospholipid antibodies are a heterogeneous group of autoantibodies that have clear associations with thrombosis and pregnancy morbidity, and which together constitute the 'antiphospholipid syndrome' (APS). However, the pathophysiology of these complications is not well understood and their heterogeneity suggests that more than one pathogenic process may be involved. Diagnosis remains a combination of laboratory analysis and clinical observation but there have been significant advances in identifying specific pathogenic features, such as domain I-specific anti-β2-glycoprotein-I antibodies. This in turn has pointed to endothelial and complement activation as important factors in the pathogenesis of APS. Consequently, although anticoagulation remains the standard treatment for thrombotic APS and during pregnancy, the realisation that these additional pathways are involved in the pathogenesis of APS has significant implications for treatment: agents acting outside the coagulation system, such as hydroxychloroquine for pregnancy complications and sirolimus as an inhibitor of the mammalian target of rapamycin (mTOR) pathway, are now under evaluation and represent a radical change in thinking for haematologists. Conventional anticoagulation is also under challenge from new, direct acting anticoagulants. This review will provide a comprehensive overview of the evolving understanding of APS pathogenesis and how this and novel therapeutics will alter diagnosis and management.
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Affiliation(s)
- Deepa R J Arachchillage
- Department of Haematology, Imperial College Healthcare NHS Trust and Imperial College London, Hammersmith Hospital, London, UK
| | - Mike Laffan
- Department of Haematology, Imperial College Healthcare NHS Trust and Imperial College London, Hammersmith Hospital, London, UK
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20
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Kagan VE, Bayır H, Tyurina YY, Bolevich SB, Maguire JJ, Fadeel B, Balasubramanian K. Elimination of the unnecessary: Intra- and extracellular signaling by anionic phospholipids. Biochem Biophys Res Commun 2017; 482:482-490. [PMID: 28212735 PMCID: PMC5319735 DOI: 10.1016/j.bbrc.2016.11.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Accepted: 11/01/2016] [Indexed: 12/19/2022]
Abstract
High fidelity of biological systems is frequently achieved by duplication of the essential intracellular machineries or, removal of the entire cell, which becomes unnecessary or even harmful in altered physiological environments. Carefully controlled removal of these cells, without damaging normal cells, requires precise signaling, and is critical to maintaining homeostasis. This review describes how two anionic phospholipids - phosphatidylserine (PS) and cardiolipin (CL) - residing in distinct compartments of the cell, signal removal of "the unnecessary" using several uniform principles. One of these principles is realized by collapse of inherent transmembrane asymmetry and the externalization of the signal on the outer membrane surface - mitochondria for CL and the plasma membrane for PS - to trigger mitophagy and phagocytosis, respectively. Release from damaged cells of intracellular structures with externalized CL or externalized PS triggers their elimination by phagocytosis. Another of these principles is realized by oxidation of polyunsaturated species of CL and PS. Highly specific oxidation of CL by cytochrome c serves as a signal for mitochondria-dependent apoptosis, while oxidation of externalized PS improves its effectiveness to trigger phagocytosis of effete cells.
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Affiliation(s)
- Valerian E Kagan
- Center for Free Radical and Antioxidant Health, University of Pittsburgh, Pittsburgh, PA, USA; Department of Environmental and Occupational Health, University of Pittsburgh, Pittsburgh, PA, USA; Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA, USA; Department of Chemistry, University of Pittsburgh, Pittsburgh, PA, USA; Department of Human Pathology, I.M. Sechenov First Moscow State Medical University, Moscow, Russia.
| | - Hülya Bayır
- Center for Free Radical and Antioxidant Health, University of Pittsburgh, Pittsburgh, PA, USA; Department of Environmental and Occupational Health, University of Pittsburgh, Pittsburgh, PA, USA; Department of Critical Care Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Yulia Y Tyurina
- Center for Free Radical and Antioxidant Health, University of Pittsburgh, Pittsburgh, PA, USA; Department of Environmental and Occupational Health, University of Pittsburgh, Pittsburgh, PA, USA
| | - Sergey B Bolevich
- Department of Human Pathology, I.M. Sechenov First Moscow State Medical University, Moscow, Russia
| | - John J Maguire
- Center for Free Radical and Antioxidant Health, University of Pittsburgh, Pittsburgh, PA, USA; Department of Environmental and Occupational Health, University of Pittsburgh, Pittsburgh, PA, USA
| | - Bengt Fadeel
- Nanosafety & Nanomedicine Laboratory, Division of Molecular Toxicology, Institute of Environmental Medicine, Karolinska Institute, Stockholm, Sweden
| | - Krishnakumar Balasubramanian
- Center for Free Radical and Antioxidant Health, University of Pittsburgh, Pittsburgh, PA, USA; Department of Environmental and Occupational Health, University of Pittsburgh, Pittsburgh, PA, USA
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21
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Ho YC, Ahuja KDK, Körner H, Adams MJ. β 2GP1, Anti-β 2GP1 Antibodies and Platelets: Key Players in the Antiphospholipid Syndrome. Antibodies (Basel) 2016; 5:E12. [PMID: 31557993 PMCID: PMC6698853 DOI: 10.3390/antib5020012] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2016] [Revised: 04/26/2016] [Accepted: 04/26/2016] [Indexed: 12/21/2022] Open
Abstract
Anti-beta 2 glycoprotein 1 (anti-β2GP1) antibodies are commonly found in patients with autoimmune diseases such as the antiphospholipid syndrome (APS) and systemic lupus erythematosus (SLE). Their presence is highly associated with increased risk of vascular thrombosis and/or recurrent pregnancy-related complications. Although they are a subtype of anti-phospholipid (APL) antibody, anti-β2GP1 antibodies form complexes with β2GP1 before binding to different receptors associated with anionic phospholipids on structures such as platelets and endothelial cells. β2GP1 consists of five short consensus repeat termed "sushi" domains. It has three interchangeable conformations with a cryptic epitope at domain 1 within the molecule. Anti-β2GP1 antibodies against this cryptic epitope are referred to as 'type A' antibodies, and have been suggested to be more strongly associated with both vascular and obstetric complications. In contrast, 'type B' antibodies, directed against other domains of β2GP1, are more likely to be benign antibodies found in asymptomatic patients and healthy individuals. Although the interactions between anti-β2GP1 antibodies, β2GP1, and platelets have been investigated, the actual targeted metabolic pathway(s) and/or receptor(s) involved remain to be clearly elucidated. This review will discuss the current understanding of the interaction between anti-β2GP1 antibodies and β2GP1, with platelet receptors and associated signalling pathways.
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Affiliation(s)
- Yik C Ho
- School of Health Sciences, University of Tasmania, Locked Bag 1322, Launceston, Tasmania 7250, Australia.
| | - Kiran D K Ahuja
- School of Health Sciences, University of Tasmania, Locked Bag 1322, Launceston, Tasmania 7250, Australia.
| | - Heinrich Körner
- Menzies Institute for Medical Research, University of Tasmania, Private Bag 23, Hobart, Tasmania 7001, Australia.
| | - Murray J Adams
- School of Health Sciences, University of Tasmania, Locked Bag 1322, Launceston, Tasmania 7250, Australia.
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22
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Bevers EM, Williamson PL. Getting to the Outer Leaflet: Physiology of Phosphatidylserine Exposure at the Plasma Membrane. Physiol Rev 2016; 96:605-45. [PMID: 26936867 DOI: 10.1152/physrev.00020.2015] [Citation(s) in RCA: 285] [Impact Index Per Article: 35.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Phosphatidylserine (PS) is a major component of membrane bilayers whose change in distribution between inner and outer leaflets is an important physiological signal. Normally, members of the type IV P-type ATPases spend metabolic energy to create an asymmetric distribution of phospholipids between the two leaflets, with PS confined to the cytoplasmic membrane leaflet. On occasion, membrane enzymes, known as scramblases, are activated to facilitate transbilayer migration of lipids, including PS. Recently, two proteins required for such randomization have been identified: TMEM16F, a scramblase regulated by elevated intracellular Ca(2+), and XKR8, a caspase-sensitive protein required for PS exposure in apoptotic cells. Once exposed at the cell surface, PS regulates biochemical reactions involved in blood coagulation, and bone mineralization, and also regulates a variety of cell-cell interactions. Exposed on the surface of apoptotic cells, PS controls their recognition and engulfment by other cells. This process is exploited by parasites to invade their host, and in specialized form is used to maintain photoreceptors in the eye and modify synaptic connections in the brain. This review discusses what is known about the mechanism of PS exposure at the surface of the plasma membrane of cells, how actors in the extracellular milieu sense surface exposed PS, and how this recognition is translated to downstream consequences of PS exposure.
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Affiliation(s)
- Edouard M Bevers
- Department of Biochemistry, Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, The Netherlands; and Department of Biology, Amherst College, Amherst, Massachusetts
| | - Patrick L Williamson
- Department of Biochemistry, Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, The Netherlands; and Department of Biology, Amherst College, Amherst, Massachusetts
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Abstract
Disulfide bonds represent versatile posttranslational modifications whose roles encompass the structure, catalysis, and regulation of protein function. Due to the oxidizing nature of the extracellular environment, disulfide bonds found in secreted proteins were once believed to be inert. This notion has been challenged by the discovery of redox-sensitive disulfides that, once cleaved, can lead to changes in protein activity. These functional disulfides are twisted into unique configurations, leading to high strain and potential energy. In some cases, cleavage of these disulfides can lead to a gain of function in protein activity. Thus, these motifs can be referred to as switches. We describe the couples that control redox in the extracellular environment, examine several examples of proteins with switchable disulfides, and discuss the potential applications of disulfides in molecular biology.
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Affiliation(s)
- Michael C Yi
- Department of Chemical Engineering, Stanford University, Stanford, California 94305; ,
| | - Chaitan Khosla
- Department of Chemical Engineering, Stanford University, Stanford, California 94305; , .,Department of Chemistry, Stanford University, Stanford, California 94305
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Balasubramanian K, Maeda A, Lee JS, Mohammadyani D, Dar HH, Jiang JF, St Croix CM, Watkins S, Tyurin VA, Tyurina YY, Klöditz K, Polimova A, Kapralova VI, Xiong Z, Ray P, Klein-Seetharaman J, Mallampalli RK, Bayir H, Fadeel B, Kagan VE. Dichotomous roles for externalized cardiolipin in extracellular signaling: Promotion of phagocytosis and attenuation of innate immunity. Sci Signal 2015; 8:ra95. [PMID: 26396268 PMCID: PMC4760701 DOI: 10.1126/scisignal.aaa6179] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Among the distinct molecular signatures present in the mitochondrion is the tetra-acylated anionic phospholipid cardiolipin, a lipid also present in primordial, single-cell bacterial ancestors of mitochondria and multiple bacterial species today. Cardiolipin is normally localized to the inner mitochondrial membrane; however, when cardiolipin becomes externalized to the surface of dysregulated mitochondria, it promotes inflammasome activation and stimulates the elimination of damaged or nonfunctional mitochondria by mitophagy. Given the immunogenicity of mitochondrial and bacterial membranes that are released during sterile and pathogen-induced trauma, we hypothesized that cardiolipins might function as "eat me" signals for professional phagocytes. In experiments with macrophage cell lines and primary macrophages, we found that membranes with mitochondrial or bacterial cardiolipins on their surface were engulfed through phagocytosis, which depended on the scavenger receptor CD36. Distinct from this process, the copresentation of cardiolipin with the Toll-like receptor 4 (TLR4) agonist lipopolysaccharide dampened TLR4-stimulated production of cytokines. These data suggest that externalized, extracellular cardiolipins play a dual role in host-host and host-pathogen interactions by promoting phagocytosis and attenuating inflammatory immune responses.
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Affiliation(s)
- Krishnakumar Balasubramanian
- Center for Free Radical and Antioxidant Health, Department of Environmental and Occupational Health, University of Pittsburgh, Pittsburgh, PA 15219, USA.
| | - Akihiro Maeda
- Division of Molecular Toxicology, Institute of Environmental Medicine, Karolinska Institutet, Stockholm 171 77, Sweden
| | - Janet S Lee
- Division of Pulmonary, Allergy and Critical Care Medicine, Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
| | - Dariush Mohammadyani
- Center for Free Radical and Antioxidant Health, Department of Environmental and Occupational Health, University of Pittsburgh, Pittsburgh, PA 15219, USA
| | - Haider Hussain Dar
- Center for Free Radical and Antioxidant Health, Department of Environmental and Occupational Health, University of Pittsburgh, Pittsburgh, PA 15219, USA
| | - Jian Fei Jiang
- Center for Free Radical and Antioxidant Health, Department of Environmental and Occupational Health, University of Pittsburgh, Pittsburgh, PA 15219, USA
| | - Claudette M St Croix
- Center for Biologic Imaging, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Simon Watkins
- Center for Biologic Imaging, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Vladimir A Tyurin
- Center for Free Radical and Antioxidant Health, Department of Environmental and Occupational Health, University of Pittsburgh, Pittsburgh, PA 15219, USA
| | - Yulia Y Tyurina
- Center for Free Radical and Antioxidant Health, Department of Environmental and Occupational Health, University of Pittsburgh, Pittsburgh, PA 15219, USA
| | - Katharina Klöditz
- Division of Molecular Toxicology, Institute of Environmental Medicine, Karolinska Institutet, Stockholm 171 77, Sweden
| | - Anastassia Polimova
- Center for Free Radical and Antioxidant Health, Department of Environmental and Occupational Health, University of Pittsburgh, Pittsburgh, PA 15219, USA
| | - Valentyna I Kapralova
- Center for Free Radical and Antioxidant Health, Department of Environmental and Occupational Health, University of Pittsburgh, Pittsburgh, PA 15219, USA
| | - Zeyu Xiong
- Division of Pulmonary, Allergy and Critical Care Medicine, Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
| | - Prabir Ray
- Division of Pulmonary, Allergy and Critical Care Medicine, Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
| | | | - Rama K Mallampalli
- Department of Internal Medicine, Acute Lung Injury Center of Excellence, University of Pittsburgh, Pittsburgh, PA 15213, USA. Veterans Affairs Pittsburgh Healthcare System, Pittsburgh, PA 15215, USA
| | - Hülya Bayir
- Center for Free Radical and Antioxidant Health, Department of Environmental and Occupational Health, University of Pittsburgh, Pittsburgh, PA 15219, USA. Department of Critical Care Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
| | - Bengt Fadeel
- Division of Molecular Toxicology, Institute of Environmental Medicine, Karolinska Institutet, Stockholm 171 77, Sweden.
| | - Valerian E Kagan
- Center for Free Radical and Antioxidant Health, Department of Environmental and Occupational Health, University of Pittsburgh, Pittsburgh, PA 15219, USA.
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25
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Ruff WE, Vieira SM, Kriegel MA. The role of the gut microbiota in the pathogenesis of antiphospholipid syndrome. Curr Rheumatol Rep 2015; 17:472. [PMID: 25475595 DOI: 10.1007/s11926-014-0472-1] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Infectious triggers are associated with the induction of transient antiphospholipid antibodies. One therefore wonders if microbes that permanently colonize us play a role in the pathogenesis of antiphospholipid syndrome (APS). The microbiota represents the collection of all microorganisms colonizing humans and is necessary for normal host physiology. The microbiota, however, is a constant stress on the immune system, which is tasked with recognizing and eliminating pathogenic microbes while tolerating commensal populations. A growing body of literature supports a critical role for the commensal-immune axis in the development of autoimmunity against colonized barriers (e.g., gut or skin) and sterile organs (e.g., pancreas or joints). Whether these interactions affect the development and sustainment of autoreactive CD4(+) T cells and pathogenic autoantibodies in APS is unknown. This review provides an overview of the current understanding of the commensal-immune axis in autoimmunity with a focus on the potential relevance to APS. Additionally, we discuss emerging findings supporting the involvement of the gut microbiota in a spontaneous model of APS, the (NZW × BXSB)F1 hybrid, and formalize hypotheses to explain how interactions between the immune system and the microbiota may influence human APS etiopathogenesis.
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Affiliation(s)
- William E Ruff
- Department of Immunobiology, Yale University School of Medicine, 300 George St, Suite 353G, New Haven, CT, 06511, USA,
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26
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Giannakopoulos B, Mirarabshahi P, Qi M, Weatherall C, Qi JC, Tanaka K, Millar E, Vonthethoff L, Gatto D, Spielman D, Krilis SA. Deletion of the antiphospholipid syndrome autoantigen β2 -glycoprotein I potentiates the lupus autoimmune phenotype in a Toll-like receptor 7-mediated murine model. Arthritis Rheumatol 2014; 66:2270-80. [PMID: 24692206 DOI: 10.1002/art.38646] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2013] [Accepted: 03/25/2014] [Indexed: 12/11/2022]
Abstract
OBJECTIVE The BXSB.Yaa mouse strain is a model of systemic lupus erythematosus that is dependent on duplication of the Toll-like receptor 7 gene. The objective of this study was to systematically describe the amplified autoimmune phenotype observed when the soluble plasma protein β2 -glycoprotein I (β2 GPI) gene was deleted in male BXSB.Yaa mice. METHODS We generated BXSB.Yaa and NZW mouse strains in which the β2 GPI gene had been knocked out by backcrossing the wild-type strains with C57BL/6 β2 GPI(-/-) mice for 10 generations. Sex- and age-matched mice of the various strains were housed under identical conditions and were killed at fixed time intervals. Serum and tissue specimens were collected at various time points. Lupus-associated autoantibodies, inflammatory cytokines, and the type I interferon (IFN) gene signature were measured. Flow cytometric analyses of lymphocyte populations were performed. The severity of glomerulonephritis was graded by 2 independent renal histopathologists. RESULTS Male BXSB.Yaa β2 GPI(-/-) mice developed significant lymphadenopathy and splenomegaly compared with age-matched controls. Male BXSB.Yaa β2 GPI(-/-) mice also had significantly higher levels of autoantibodies, increased levels of inflammatory cytokines including tumor necrosis factor α, interleukin-6, and BAFF, and more severe glomerulonephritis. The type I IFN gene signature in male BXSB.Yaa β2 GPI(-/-) mice was significantly higher than that in control mice. Male BXSB.Yaa β2 GPI(-/-) mice also had marked dysregulation of various B cell and T cell populations in the spleens and lymph nodes and a disturbance in apoptotic cell clearance. CONCLUSION Deletion of β2 GPI accelerates and potentiates the autoimmune phenotype in male BXSB.Yaa mice.
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Affiliation(s)
- Bill Giannakopoulos
- St. George Hospital and University of New South Wales, Kogarah, New South Wales, Australia
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27
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Andreoli L, Fredi M, Nalli C, Franceschini F, Meroni PL, Tincani A. Antiphospholipid antibodies mediate autoimmunity against dying cells. Autoimmunity 2013; 46:302-6. [PMID: 23713583 DOI: 10.3109/08916934.2013.783025] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The Antiphospholipid Syndrome (APS) is characterized by thrombosis and pregnancy loss, clinical events mediated by pathogenic anti-phospholipid autoantibodies (aPL). β2-glycoprotein I (β2GPI) is the major autoantigens recognized by aPL. β2GPI is a cationic protein that binds to negatively charged surfaces such as those of apoptotic cells. This feature may lead to two major events: i) immunization with β2GPI fosters the Fc-receptor-mediated uptake by antigen presenting cells of apoptotic material decorated with β2GPI and the activation of β2GPI-specific T cells which in turn provide help to β2GPI-specific B cells for the production of anti-β2GPI; ii) apoptotic bodies decorated with β2GPI can be opsonized by anti-β2GPI and shifted towards a pro-inflammatory clearance by macrophages; epitope spread can occur with the generation of autoimmunity against nuclear autoantigens. In the presence of a predisposing genetic background and of a particular cytokine environment (type I interferons), the sequential emergence of autoantibodies can evolve into overt clinical disease. The spectrum of clinical phenotypes of the patients can be modulated by several factors affecting the pathogenicity of anti-β2GPI (e.g. domain specificity). We conclude that dying cells may play a dual role in APS: (I) as immunogen for the induction of aPL (etiology) and (II) as targets of aPL for the chronification of inflammation and the development of autoimmune diseases (pathology).
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Affiliation(s)
- Laura Andreoli
- Rheumatology and Clinical Immunology, Spedali Civili and University of Brescia, Italy.
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28
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Lauber K, Ernst A, Orth M, Herrmann M, Belka C. Dying cell clearance and its impact on the outcome of tumor radiotherapy. Front Oncol 2012; 2:116. [PMID: 22973558 PMCID: PMC3438527 DOI: 10.3389/fonc.2012.00116] [Citation(s) in RCA: 129] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2012] [Accepted: 08/27/2012] [Indexed: 12/29/2022] Open
Abstract
The induction of tumor cell death is one of the major goals of radiotherapy and has been considered to be the central determinant of its therapeutic outcome for a long time. However, accumulating evidence suggests that the success of radiotherapy does not only derive from direct cytotoxic effects on the tumor cells alone, but instead might also depend – at least in part – on innate as well as adaptive immune responses, which can particularly target tumor cells that survive local irradiation. The clearance of dying tumor cells by phagocytic cells of the innate immune system represents a crucial step in this scenario. Dendritic cells and macrophages, which engulf, process and present dying tumor cell material to adaptive immune cells, can trigger, skew, or inhibit adaptive immune responses, respectively. In this review we summarize the current knowledge of different forms of cell death induced by ionizing radiation, the multi-step process of dying cell clearance, and its immunological consequences with special regard toward the potential exploitation of these mechanisms for the improvement of tumor radiotherapy.
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Affiliation(s)
- Kirsten Lauber
- Department of Radiotherapy and Radiation Oncology, Ludwig Maximilian University of Munich Munich, Germany
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29
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Ortel TL. Antiphospholipid syndrome: laboratory testing and diagnostic strategies. Am J Hematol 2012; 87 Suppl 1:S75-81. [PMID: 22473619 DOI: 10.1002/ajh.23196] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2011] [Accepted: 03/05/2012] [Indexed: 12/13/2022]
Abstract
The antiphospholipid syndrome (APS) is diagnosed in patients with recurrent thromboembolic events and/or pregnancy loss in the presence of persistent laboratory evidence for antiphospholipid antibodies. Diagnostic tests for the detection of antiphospholipid antibodies include laboratory assays that detect anticardiolipin antibodies, lupus anticoagulants, and anti-β(2)-glycoprotein I antibodies. These assays have their origins beginning >60 years ago, with the identification of the biologic false positive test for syphilis, the observation of "circulating anticoagulants" in certain patients with systemic lupus erythematosus, the identification of cardiolipin as a key component in the serologic test for syphilis, and the recognition and characterization of a "cofactor" for antibody binding to phospholipids. Although these assays have been used clinically for many years, there are still problems with the accurate diagnosis of patients with this syndrome. For example, lupus anticoagulant testing can be difficult to interpret in patients receiving anticoagulant therapy, but most patients with a thromboembolic event will already be anticoagulated before the decision to perform the tests has been made. In addition to understanding limitations of the assays, clinicians also need to be aware of which patients should be tested and not obtain testing on patients unlikely to have APS. New tests and diagnostic strategies are in various stages of development and should help improve our ability to accurately diagnose this important clinical disorder.
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Affiliation(s)
- Thomas L Ortel
- Division of Hematology, Duke University Medical Center, Durham, North Carolina, USA.
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30
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Lodge R, Ouellet M, Barat C, Andreani G, Kumar P, Tremblay MJ. HIV-1 promotes intake of Leishmania parasites by enhancing phosphatidylserine-mediated, CD91/LRP-1-dependent phagocytosis in human macrophages. PLoS One 2012; 7:e32761. [PMID: 22412921 PMCID: PMC3295765 DOI: 10.1371/journal.pone.0032761] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2011] [Accepted: 02/02/2012] [Indexed: 12/22/2022] Open
Abstract
Over the past decade, the number of reported human immunodeficiency virus type-1 (HIV-1)/Leishmania co-infections has risen dramatically, particularly in regions where both diseases are endemic. Although it is known that HIV-1 infection leads to an increase in susceptibility to Leishmania infection and leishmaniasis relapse, little remains known on how HIV-1 contributes to Leishmania parasitaemia. Both pathogens infect human macrophages, and the intracellular growth of Leishmania is increased by HIV-1 in co-infected cultures. We now report that uninfected bystander cells, not macrophages productively infected with HIV-1, account for enhanced phagocytosis and higher multiplication of Leishmania parasites. This effect can be driven by HIV-1 Tat protein and transforming growth factor-beta (TGF-β). Furthermore, we show for the first time that HIV-1 infection increases surface expression of phosphatidylserine receptor CD91/LRP-1 on human macrophages, thereby leading to a Leishmania uptake by uninfected bystander cells in HIV-1-infected macrophage populations. The more important internalization of parasites is due to interactions between the scavenger receptor CD91/LRP-1 and phosphatidylserine residues exposed at the surface of Leishmania. We determined also that enhanced CD91/LRP-1 surface expression occurs rapidly following HIV-1 infection, and is triggered by the activation of extracellular TGF-β. Thus, these results establish an intricate link between HIV-1 infection, Tat, surface CD91/LRP-1, TGF-β, and enhanced Leishmania phosphatidylserine-mediated phagocytosis.
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Affiliation(s)
- Robert Lodge
- Centre de Recherche en Infectiologie, Centre Hospitalier Universitaire de Québec - CHUL, Université Laval, Québec, Canada
- Département de Microbiologie-Infectiologie et Immunologie, Faculté de Médecine, Université Laval, Québec, Canada
| | - Michel Ouellet
- Centre de Recherche en Infectiologie, Centre Hospitalier Universitaire de Québec - CHUL, Université Laval, Québec, Canada
- Département de Microbiologie-Infectiologie et Immunologie, Faculté de Médecine, Université Laval, Québec, Canada
| | - Corinne Barat
- Centre de Recherche en Infectiologie, Centre Hospitalier Universitaire de Québec - CHUL, Université Laval, Québec, Canada
- Département de Microbiologie-Infectiologie et Immunologie, Faculté de Médecine, Université Laval, Québec, Canada
| | - Guadalupe Andreani
- Centre de Recherche en Infectiologie, Centre Hospitalier Universitaire de Québec - CHUL, Université Laval, Québec, Canada
- Département de Microbiologie-Infectiologie et Immunologie, Faculté de Médecine, Université Laval, Québec, Canada
| | - Pranav Kumar
- Centre de Recherche en Infectiologie, Centre Hospitalier Universitaire de Québec - CHUL, Université Laval, Québec, Canada
- Département de Microbiologie-Infectiologie et Immunologie, Faculté de Médecine, Université Laval, Québec, Canada
| | - Michel J. Tremblay
- Centre de Recherche en Infectiologie, Centre Hospitalier Universitaire de Québec - CHUL, Université Laval, Québec, Canada
- Département de Microbiologie-Infectiologie et Immunologie, Faculté de Médecine, Université Laval, Québec, Canada
- * E-mail:
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Li W. Eat-me signals: keys to molecular phagocyte biology and "appetite" control. J Cell Physiol 2012; 227:1291-7. [PMID: 21520079 DOI: 10.1002/jcp.22815] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Hundreds of billions of cells undergo apoptosis in our body everyday and are removed by immunologically silent phagocytosis to maintain tissue homeostasis. Impairments in phagocytosis result in autoimmune and/or degenerative diseases. Eat-me signals are the key to the recognition of extracellular cargos and the initiation of the phagocytosis process by activating phagocytic receptors and signaling cascades, and are convenient targets for therapeutic modulation. Despite their importance, eat-me signals and other phagocytosis players are mostly identified on case-by-case basis with daunting challenges. This Commentary focuses on our latest knowledge of the extracellular players, highlights our approaches to systematically map unknown pathways by functional genetic and proteomic technologies, and discusses future direction to unravel the mystery of molecular phagocyte biology.
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Affiliation(s)
- Wei Li
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami School of Medicine, Miami, Florida 33136, USA.
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32
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Ioannou Y, Zhang JY, Qi M, Gao L, Qi JC, Yu DM, Lau H, Sturgess AD, Vlachoyiannopoulos PG, Moutsopoulos HM, Rahman A, Pericleous C, Atsumi T, Koike T, Heritier S, Giannakopoulos B, Krilis SA. Novel assays of thrombogenic pathogenicity in the antiphospholipid syndrome based on the detection of molecular oxidative modification of the major autoantigen β2-glycoprotein I. ACTA ACUST UNITED AC 2011; 63:2774-82. [PMID: 21618459 PMCID: PMC3328749 DOI: 10.1002/art.30383] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Objective Beta-2-glycoprotein I (β2GPI) constitutes the major autoantigen in the antiphospholipid syndrome (APS), a common acquired cause of arterial and venous thrombosis. We recently described the novel observation that β2GPI may exist in healthy individuals in a free thiol (biochemically reduced) form. The present study was undertaken to quantify the levels of total, reduced, and posttranslationally modified oxidized β2GPI in APS patients compared to various control groups. Methods In a retrospective multicenter analysis, the proportion of β2GPI with free thiols in serum from healthy volunteers was quantified. Assays for measurement of reduced as well as total circulating β2GPI were developed and tested in the following groups: APS (with thrombosis) (n = 139), autoimmune disease with or without persistent antiphospholipid antibodies (aPL) but without APS (n = 188), vascular thrombosis without APS or aPL (n = 38), and healthy volunteers (n = 91). Results Total β2GPI was significantly elevated in patients with APS (median 216.2 μg/ml [interquartile range 173.3–263.8]) as compared to healthy subjects (median 178.4 μg/ml [interquartile range 149.4–227.5] [P < 0.0002]) or control patients with autoimmune disease or vascular thrombosis (both P < 0.0001). The proportion of total β2GPI in an oxidized form (i.e., lacking free thiols) was significantly greater in the APS group than in each of the 3 control groups (all P < 0.0001). Conclusion This large retrospective multicenter study shows that posttranslational modification of β2GPI via thiol-exchange reactions is a highly specific phenomenon in the setting of APS thrombosis. Quantification of posttranslational modifications of β2GPI in conjunction with standard laboratory tests for APS may offer the potential to more accurately predict the risk of occurrence of a thrombotic event in the setting of APS.
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Affiliation(s)
- Yiannis Ioannou
- Department of Immunology, St. George Hospital and University of New South Wales, Sydney, New South Wales, Australia
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Laplante P, Amireault P, Subang R, Dieudé M, Levine JS, Rauch J. Interaction of β2-glycoprotein I with lipopolysaccharide leads to Toll-like receptor 4 (TLR4)-dependent activation of macrophages. J Biol Chem 2011; 286:42494-42503. [PMID: 21965665 DOI: 10.1074/jbc.m111.230383] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
β(2)-Glycoprotein I (β(2)GPI) is an abundant plasma protein that binds to the surface of cells and particles expressing negatively charged lipids, but its physiological role remains unknown. Antibodies to β(2)GPI are found in patients with anti-phospholipid syndrome, a systemic autoimmune disease associated with vascular thrombosis and pregnancy morbidity. Although it has been suggested that anti-β(2)GPI antibodies activate endothelial cells and monocytes by signaling through TLR4, it is unclear how anti-β(2)GPI antibodies and/or β(2)GPI interact with TLR4. A number of mammalian proteins (termed "endogenous Toll-like receptor (TLR) ligands") have been reported to bind to TLR4, but, in most cases, subsequent studies have shown that LPS interaction with these proteins is responsible for TLR activation. We hypothesized that, like other endogenous TLR ligands, β(2)GPI interacts specifically with LPS and that this interaction is responsible for apparent TLR4 activation by β(2)GPI. Here, we show that both LPS and TLR4 are required for β(2)GPI to bind to and activate macrophages. Untreated β(2)GPI stimulated TNF-α production in TLR4-sufficient (but not TLR4-deficient) macrophages. In contrast, neither polymyxin B-treated nor delipidated β(2)GPI stimulated TNF-α production. Furthermore, β(2)GPI bound to LPS in a specific and dose-dependent manner. Finally, untreated β(2)GPI bound to the surface of TLR4-sufficient (but not TLR4-deficient) macrophages. Polymyxin B treatment of β(2)GPI abolished macrophage binding. Our findings suggest a potential new biological activity for β(2)GPI as a protein that interacts specifically with LPS and point to the need to evaluate newly discovered endogenous TLR ligands for potential interactions with LPS.
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Affiliation(s)
- Patrick Laplante
- Division of Rheumatology, Department of Medicine, Research Institute of the McGill University Health Centre, Montreal, Quebec H3G 1A4, Canada
| | - Pascal Amireault
- Division of Rheumatology, Department of Medicine, Research Institute of the McGill University Health Centre, Montreal, Quebec H3G 1A4, Canada
| | - Rebecca Subang
- Division of Rheumatology, Department of Medicine, Research Institute of the McGill University Health Centre, Montreal, Quebec H3G 1A4, Canada
| | - Mélanie Dieudé
- Division of Rheumatology, Department of Medicine, Research Institute of the McGill University Health Centre, Montreal, Quebec H3G 1A4, Canada
| | - Jerrold S Levine
- Section of Nephrology, Department of Medicine, University of Illinois at Chicago, Chicago, Illinois 60680; Section of Nephrology, Department of Medicine, Jesse Brown Veterans Affairs Medical Center, Chicago, Illinois 60612
| | - Joyce Rauch
- Division of Rheumatology, Department of Medicine, Research Institute of the McGill University Health Centre, Montreal, Quebec H3G 1A4, Canada.
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Yancey PG, Ding Y, Fan D, Blakemore JL, Zhang Y, Ding L, Zhang J, Linton MF, Fazio S. Low-density lipoprotein receptor-related protein 1 prevents early atherosclerosis by limiting lesional apoptosis and inflammatory Ly-6Chigh monocytosis: evidence that the effects are not apolipoprotein E dependent. Circulation 2011; 124:454-64. [PMID: 21730304 DOI: 10.1161/circulationaha.111.032268] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
BACKGROUND We previously demonstrated that macrophage low-density lipoprotein receptor (LDLR)-related protein 1 (LRP1) deficiency increases atherosclerosis despite antiatherogenic changes including decreased uptake of remnants and increased secretion of apolipoprotein E (apoE). Thus, our objective was to determine whether the atheroprotective effects of LRP1 require interaction with apoE, one of its ligands with multiple beneficial effects. METHODS AND RESULTS We examined atherosclerosis development in mice with specific deletion of macrophage LRP1 (apoE(-/-) MΦLRP1(-/-)) and in LDLR(-/-) mice reconstituted with apoE(-/-) MΦLRP1(-/-) bone marrow. The combined absence of apoE and LRP1 promoted atherogenesis more than did macrophage apoE deletion alone in both apoE-producing LDLR(-/-) mice (+88%) and apoE(-/-) mice (+163%). The lesions of both mouse models with apoE(-/-) LRP1(-/-) macrophages had increased macrophage content. In vitro, apoE and LRP1 additively inhibit macrophage apoptosis. Furthermore, there was excessive accumulation of apoptotic cells in lesions of both LDLR(-/-) mice (+110%) and apoE(-/-) MΦLRP1(-/-) mice (+252%). The apoptotic cell accumulation was partially due to decreased efferocytosis as the ratio of free to cell-associated apoptotic nuclei was 3.5-fold higher in lesions of apoE(-/-) MΦLRP1(-/-) versus apoE(-/-) mice. Lesion necrosis was also increased (6 fold) in apoE(-/-) MΦLRP1(-/-) versus apoE(-/-) mice. Compared with apoE(-/-) mice, the spleens of apoE(-/-) MΦLRP1(-/-) mice contained 1.6- and 2.4-fold more total and Ly6-C(high) monocytes. Finally, there were 3.6- and 2.4-fold increases in Ly6-C(high) and CC-chemokine receptor 2-positive cells in lesions of apoE(-/-) MΦLRP1(-/-) versus apoE(-/-) mice, suggesting that accumulation of apoptotic cells enhances lesion development and macrophage content by promoting the recruitment of inflammatory monocytes. CONCLUSION Low-density lipoprotein receptor protein 1 exerts antiatherogenic effects via pathways independent of apoE involving macrophage apoptosis and monocyte recruitment.
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Affiliation(s)
- Patricia G Yancey
- Atherosclerosis Research Unit, Division of Cardiology, Department of Medicine, Vanderbilt University Medical Center, 2220 Pierce Avenue, Nashville, TN 37232, USA.
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Abstract
β(2) -Glycoprotein I (β(2) -GPI) is a protein that circulates in blood at high concentrations. The function of β(2) -GPI has long been an enigma. More than 20 years ago, it was discovered that β(2) -GPI is the major antigen for the circulating antibodies in the antiphospholipid syndrome. However, this knowledge has not advanced our understanding of the physiologic role of the protein. In recent years, new insights have suggested an important function of this protein in innate immunity. β(2) -GPI was found to scavenge lipopolysaccharide and was able to clear unwanted anionic cellular remnants such as microparticles from the circulation. The function of β(2) -GPI seems to depend on the structural conformation of the protein, and it has been established that β(2) -GPI can exist in at least two conformations. In this review, we will highlight and summarize the current knowledge on this protein.
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Affiliation(s)
- P G de Groot
- Department of Clinical Chemistry and Hematology, University Medical Center, Utrecht, the Netherlands.
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Naturally occurring free thiols within β2-glycoprotein I in vivo: nitrosylation, redox modification by endothelial cells, and regulation of oxidative stress–induced cell injury. Blood 2010; 116:1961-70. [DOI: 10.1182/blood-2009-04-215335] [Citation(s) in RCA: 93] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Abstractβ2-Glycoprotein I (β2GPI) is an evolutionary conserved, abundant circulating protein. Although its function remains uncertain, accumulated evidence points toward interactions with endothelial cells and components of the coagulation system, suggesting a regulatory role in vascular biology. Our group has shown that thioredoxin 1 (TRX-1) generates free thiols in β2GPI, a process that may have a regulatory role in platelet adhesion. This report extends these studies and shows for the first time evidence of β2GPI with free thiols in vivo in both multiple human and murine serum samples. To explore how the vascular surface may modulate the redox status of β2GPI, unstimulated human endothelial cells and EAhy926 cells are shown to be capable of amplifying the effect of free thiol generation within β2GPI. Multiple oxidoreductase enzymes, such as endoplasmic reticulum protein 46 (ERp 46) and TRX-1 reductase, in addition to protein disulfide isomerase are secreted on the surface of endothelial cells. Furthermore, one or more of these generated free thiols within β2GPI are also shown to be nitrosylated. Finally, the functional significance of these findings is explored, by showing that free thiol–containing β2GPI has a powerful effect in protecting endothelial cells and EAhy926 cells from oxidative stress–induced cell death.
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Passam FH, Qi JC, Tanaka K, Matthaei KI, Krilis SA. In vivo modulation of angiogenesis by beta 2 glycoprotein I. J Autoimmun 2010; 35:232-40. [PMID: 20655705 DOI: 10.1016/j.jaut.2010.06.013] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Beta 2 glycoprotein I (β2GPI) is the major auto antigen in the antiphospholipid syndrome but also interacts with fibrinolytic and angiogenic proteins. The aim of this study was to examine the angiogenic potential of β2GPI in vivo in β2GPI deficient mice utilizing angiogenic assays. β2GPI deficient mice show increased microvessel formation in comparison to β2GPI replete controls when injected with growth factor free-matrigel implants. However, microvessel formation in matrigel plugs of β2GPI deficient mice was less than in β2GPI replete mice when basic fibroblast growth factor (bFGF) was included in the matrigel. Hemoglobin content was higher in vascular endothelial growth factor (VEGF) containing-matrigel plugs in the β2GPI deficient mouse demonstrating that the lack of β2GPI led to increased extravasation by VEGF. Melanoma B16F10 tumour growth was enhanced in β2GPI deficient mice. Melanoma microvessel density was increased in β2GPI deficient mice but the proliferation rate of tumour cells (determined by Ki67 immunohistochemistry) was unaffected by the presence or absence of β2GPI. Subcutaneous delivery of native human β2GPI by the ALZET osmotic pump did not affect melanoma tumour growth in β2GPI deficient mice. We conclude that the in vivo unopposed action of β2GPI is anti-angiogenic however this function is modified in the presence of a strong angiogenic stimulus into stabilization of vessel formation. Although the presence of β2GPI attenuates vessel sprouting in certain tumours, no survival benefit is conferred to tumour bearing animals. This does not preclude the potential benefit of modified or fragments of β2GPI in anti-angiogenesis research.
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Affiliation(s)
- F H Passam
- Department of Immunology, Allergy and Infectious Disease, University of New South Wales, St. George Hospital, 2 South St., Kogarah, NSW 2217, Sydney, Australia
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Muslin AJ. Phenotypic high-throughput screening in atherosclerosis research: focus on macrophages. J Cardiovasc Transl Res 2010; 3:448-53. [PMID: 20625867 DOI: 10.1007/s12265-010-9205-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/07/2010] [Accepted: 06/21/2010] [Indexed: 10/19/2022]
Abstract
Atherosclerosis is a complex disease characterized by arterial lesions consisting of macrophage foam cells, smooth muscle cells, lymphocytes and other cell types. As atherosclerotic lesions mature, they can rupture and thereby trigger thrombosis that can result in tissue infarction. Macrophage foam cells develop in the subendothelial space when cells take up cholesterol from modified forms of low-density lipoprotein (LDL) and other apolipoprotein B-containing lipoproteins. Current therapies to limit atherosclerosis focus on altering the plasma lipid composition, most commonly by reducing circulating LDL levels. No current therapy is specifically designed to alter the cellular composition of atherosclerotic lesions. To address this deficit, phenotypic high-throughput drug screens have been developed to identify compounds that reduce the uptake of oxidized LDL by macrophages or to identify compounds that increase the efflux of cholesterol from macrophages. Additional phenotypic screens can be envisaged that address cellular processes in active atherosclerotic lesions including macrophage apoptosis and efferocytosis.
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Affiliation(s)
- Anthony J Muslin
- Center for Cardiovascular Research, Washington University School of Medicine, 660 South Euclid Avenue, Box 8086, St. Louis, MO 63110, USA.
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Mode of Interaction between β2GPI and Lipoprotein Receptors Suggests Mutually Exclusive Binding of β2GPI to the Receptors and Anionic Phospholipids. Structure 2010; 18:366-76. [DOI: 10.1016/j.str.2009.12.013] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2009] [Revised: 11/30/2009] [Accepted: 12/29/2009] [Indexed: 12/20/2022]
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Abstract
The antiphospholipid syndrome is defined by the presence of antiphospholipid antibodies in patients with recurrent venous or arterial thromboembolism or pregnancy morbidity. Antithrombotic therapies are the mainstay of treatment to reduce the risk of recurrent thromboembolism. Among patients with antiphospholipid antibodies, the absolute risk of new thrombosis developing is low in healthy patients without previous thrombotic events. However, the risk of recurrent thrombosis appears to be high in patients with a history of arterial or venous thrombosis. Compared with placebo or untreated control, anticoagulation with warfarin administered to achieve an international normalized ratio of 2.0 to 3.0 probably reduces the risk of recurrence of thrombotic events. Aspirin and moderate-intensity warfarin appear equally effective for preventing recurrent stroke in patients with a single positive antiphospholipid antibody test result and previous stroke. It is unknown how best to prevent first stroke in patients found to be persistently positive for the antiphospholipid syndrome. The catastrophic variant of the antiphospholipid syndrome is a condition characterized by multiple vascular occlusive events, usually affecting small vessels and evolving over a short period of time. This condition has a very high mortality rate. First-line treatment with therapeutic anticoagulation, corticosteroids, plasma exchange, and intravenous immunoglobulin seems to be effective in reducing mortality and risk of catastrophic thrombotic events in these patients. In conclusion, moderate-intensity warfarin is effective for preventing recurrent thrombotic events in patients with venous thrombosis. Aspirin appears to be as effective as moderate-intensity warfarin for preventing recurrent stroke in patients with previous stroke and a single positive test result for antiphospholipid antibody. The optimal treatment of other clinical manifestations of antiphospholipid syndrome needs to be addressed in well-designed prospective studies.
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Yancey PG, Blakemore J, Ding L, Fan D, Overton CD, Zhang Y, Linton MF, Fazio S. Macrophage LRP-1 controls plaque cellularity by regulating efferocytosis and Akt activation. Arterioscler Thromb Vasc Biol 2010; 30:787-95. [PMID: 20150557 DOI: 10.1161/atvbaha.109.202051] [Citation(s) in RCA: 122] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVE The balance between apoptosis susceptibility and efferocytosis of macrophages is central to plaque remodeling and inflammation. LRP-1 and its ligand, apolipoprotein E, have been implicated in efferocytosis and apoptosis in some cell types. We investigated the involvement of the macrophage LRP-1/apolipoprotein E axis in controlling plaque apoptosis and efferocytosis. Method and Results- LRP-1(-/-) macrophages displayed nearly 2-fold more TUNEL positivity compared to wild-type cells in the presence of DMEM alone or with either lipopolysaccharide or oxidized low-density lipoprotein. The survival kinase, phosphorylated Akt, was barely detectable in LRP-1(-/-) cells, causing decreased phosphorylated Bad and increased cleaved caspase-3. Regardless of the apoptotic stimulation and degree of cell death, LRP-1(-/-) macrophages displayed enhanced inflammation with increased IL-1 beta, IL-6, and tumor necrosis factor-alpha expression. Efferocytosis of apoptotic macrophages was reduced by 60% in LRP-1(-/-) vs wild-type macrophages despite increased apolipoprotein E expression by both LRP-1(-/-) phagocytes and wild-type apoptotic cells. Compared to wild-type macrophage lesions, LRP-1(-/-) lesions had 5.7-fold more necrotic core with more dead cells not associated with macrophages. CONCLUSIONS Macrophage LRP-1 deficiency increases cell death and inflammation by impairing phosphorylated Akt activation and efferocytosis. Increased apolipoprotein E expression in LRP-1(-/-) macrophages suggests that the LRP-1/apolipoprotein E axis regulates the balance between apoptosis and efferocytosis, thereby preventing necrotic core formation.
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Affiliation(s)
- Patricia G Yancey
- Division of Cardiology, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37232, USA.
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Beglov D, Lee CJ, De Biasio A, Kozakov D, Brenke R, Vajda S, Beglova N. Structural insights into recognition of beta2-glycoprotein I by the lipoprotein receptors. Proteins 2010; 77:940-9. [PMID: 19676115 DOI: 10.1002/prot.22519] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The interactions of beta2 glycoprotein I (B2GPI) with the receptors of the low-density lipoprotein receptor (LDLR) family are implicated in the clearance of negatively charged phospholipids and apoptotic cells and, in the presence of autoimmune anti-B2GPI antibodies, in cell activation, which might play a role in the pathology of antiphospholipid syndrome (APS). The ligand-binding domains of the lipoprotein receptors consist of multiple homologous LA modules connected by flexible linkers. In this study, we investigated at the atomic level the features of the LA modules required for binding to B2GPI. To compare the binding interface in B2GPI/LA complex to that observed in the high-resolution co-crystal structure of the receptor associated protein (RAP) with a pair of LA modules 3 and 4 from the LDLR, we used LA4 in our studies. Using solution NMR spectroscopy, we found that LA4 interacts with B2GPI and the binding site for B2GPI on the (15)N-labeled LA4 is formed by the calcium coordinating residues of the LA module. We built a model for the complex between domain V of B2GPI (B2GPI-DV) and LA4 without introducing any experimentally derived constraints into the docking procedure. Our model, which is in the agreement with the NMR data, suggests that the binding interface of B2GPI for the lipoprotein receptors is centered at three lysine residues of B2GPI-DV, Lys 308, Lys 282, and Lys317.
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Affiliation(s)
- Dmitri Beglov
- Department of Biomedical Engineering, Boston University, Boston, Massachusetts 02215, USA
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Immunogenic oxidized low-density lipoprotein/beta2-glycoprotein I complexes in the diagnostic management of atherosclerosis. Clin Rev Allergy Immunol 2009; 37:12-9. [PMID: 18982458 DOI: 10.1007/s12016-008-8096-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Oxidized low-density lipoprotein (oxLDL) promotes atherosclerosis through a complex interaction of inflammatory and immunologic factors that lead to macrophage lipid uptake and foam cell formation. OxLDL interacts with beta2-glycoprotein I (beta2GPI) forming oxLDL/beta2GPI complexes. These complexes may be formed in the arterial intima during atherogenesis and released into the circulation. Autoantibodies against oxLDL/beta2GPI complexes have been demonstrated in patients with systemic lupus erythematosus and/or antiphospholipid syndrome, and shown to be significantly associated with arterial thrombosis. The observation that monoclonal autoantibodies against oxLDL/beta2GPI complexes significantly increased the oxLDL uptake by macrophages strongly suggests that such IgG autoantibodies are pro-atherogenic. In this article, we review the recent progress in our understanding of LDL oxidation, oxLDL/beta2GPI complex formation, and immune regulation of atherogenesis.
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Reed JH, Giannakopoulos B, Jackson MW, Krilis SA, Gordon TP. Ro 60 functions as a receptor for beta(2)-glycoprotein I on apoptotic cells. ACTA ACUST UNITED AC 2009; 60:860-9. [PMID: 19248095 DOI: 10.1002/art.24361] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
OBJECTIVE The autoantigens 60-kd Ro/SSA (Ro 60) and beta(2)-glycoprotein I (beta(2)GPI) are both displayed on the surface membrane of apoptotic cells. Epitope-spreading experiments have suggested that these autoantigens may be present as a complex on the apoptotic cell surface. This study was undertaken to investigate whether beta(2)GPI interacts with Ro 60 on apoptotic cells and alters the binding of anti-Ro 60 IgG. METHODS The interaction between soluble recombinant Ro 60 fragments and beta(2)GPI was investigated in vitro by direct and saturation binding assays using native human beta(2)GPI and recombinant domain deletion mutants. Binding of beta(2)GPI to early and late apoptotic cells was assessed by multiparameter flow cytometry, and specificity of binding was determined by competitive inhibition with soluble recombinant Ro 60 and anti-Ro 60 IgG. RESULTS The Ro 60 fragment expressing a surface-exposed epitope (apotope) bound with high affinity (K(d) = approximately 15 nM) to domain V of beta(2)GPI in vitro. Beta(2)-glycoprotein I bound to the surface of apoptotic cells in a dose-dependent manner and was blocked by the Ro 60 apotope fragment. In reciprocal competitive inhibition studies, beta(2)GPI blocked the binding of anti-Ro 60 autoantibodies to apoptotic cells in a dose-dependent manner, and anti-Ro 60 IgG inhibited the binding of beta(2)GPI. Moreover, beta(2)GPI showed a 2-fold increase in binding to apoptotic cells that overexpress Ro 60 on the surface. CONCLUSION These results demonstrate that Ro 60 functions as a novel receptor for beta(2)GPI on the surface of apoptotic cells. The formation of Ro 60-beta(2)GPI complexes may protect against anti-Ro 60 autoantibody-mediated tissue injury.
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Affiliation(s)
- Joanne H Reed
- Flinders University of South Australia, Adelaide, and Flinders Medical Centre, Bedford Park, South Australia, Australia
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Farmer-Boatwright MK, Roubey RA. Venous Thrombosis in the Antiphospholipid Syndrome. Arterioscler Thromb Vasc Biol 2009; 29:321-5. [DOI: 10.1161/atvbaha.108.182204] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Mary Katherine Farmer-Boatwright
- From the Division of Rheumatology, Allergy and Immunology, Department of Medicine, and Thurston Arthritis Research Center, The University of North Carolina at Chapel Hill
| | - Robert A.S. Roubey
- From the Division of Rheumatology, Allergy and Immunology, Department of Medicine, and Thurston Arthritis Research Center, The University of North Carolina at Chapel Hill
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Abstract
Antiphospholipid (aPL) antibodies are clinically important acquired risk factors for thrombosis and pregnancy loss and are thought to have a direct prothrombotic effect in vivo. Data suggest that a major mechanism by which aPL antibodies contribute to thrombophilia is the upregulation of tissue factor (TF) (CD142) on blood cells and vascular endothelium. TF is the physiological trigger of normal blood coagulation and thrombosis in many hypercoagulable conditions. This article reviews the physiology of TF, the molecular regulation of TF expression and the effects of aPL antibodies on intravascular TF regulation and expression. Inhibition of TF and the pathways by which aPL antibodies induce TF expression are potentially attractive therapeutic targets in the antiphospholipid syndrome.
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Affiliation(s)
- A V Kinev
- Department of Medicine and Thurston Arthritis Research Center, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-7280, USA
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van Genderen HO, Kenis H, Hofstra L, Narula J, Reutelingsperger CPM. Extracellular annexin A5: functions of phosphatidylserine-binding and two-dimensional crystallization. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2008; 1783:953-63. [PMID: 18334229 DOI: 10.1016/j.bbamcr.2008.01.030] [Citation(s) in RCA: 151] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2007] [Revised: 01/22/2008] [Accepted: 01/23/2008] [Indexed: 02/06/2023]
Abstract
In normal healthy cells phosphatidylserine is located in the inner leaflet of the plasma membrane. However, on activated platelets, dying cells and under specific circumstances also on various types of viable leukocytes phosphatidylserine is actively externalized to the outer leaflet of the plasma membrane. Annexin A5 has the ability to bind in a calcium-dependent manner to phosphatidylserine and to form a membrane-bound two-dimensional crystal lattice. Based on these abilities various functions for extracellular annexin A5 on the phosphatidylserine-expressing plasma membrane have been proposed. In this review we describe possible mechanisms for externalization of annexin A5 and various processes in which extracellular annexin A5 may play a role such as blood coagulation, apoptosis, phagocytosis and formation of plasma membrane-derived microparticles. We further highlight the recent discovery of internalization of extracellular annexin A5 by phosphatidylserine-expressing cells.
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Affiliation(s)
- Hugo O van Genderen
- Department of Biochemistry, Cardiovascular Research Institute Maastricht, University Maastricht, Maastricht, The Netherlands
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