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Halfon M, Zhang L, Ehirchiou D, Pandian VD, Dahdal S, Huynh-Do U, Pasch A, Ribi C, Busso N. ITGAM rs1143679 Variant in Systemic Lupus Erythematosus Is Associated with Increased Serum Calcification Propensity. Genes (Basel) 2023; 14:genes14051105. [PMID: 37239465 DOI: 10.3390/genes14051105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Revised: 05/11/2023] [Accepted: 05/15/2023] [Indexed: 05/28/2023] Open
Abstract
OBJECTIVES CD11B/ITGAM (Integrin Subunit α M) mediates the adhesion of monocytes, macrophages, and granulocytes and promotes the phagocytosis of complement-coated particles. Variants of the ITGAM gene are candidates for genetic susceptibility to systemic lupus erythematosus (SLE). SNP rs1143679 (R77H) of CD11B particularly increases the risk of developing SLE. Deficiency of CD11B is linked to premature extra-osseous calcification, as seen in the cartilage of animals with osteoarthritis. Serum calcification propensity measured by the T50 test is a surrogate marker for systemic calcification and reflects increased cardiovascular (CV) risk. We aimed to assess whether the CD11B R77H gene variant is associated with a higher serum calcification propensity (i.e., a lower T50 value) in SLE patients compared to the wild-type allele (WT). METHODS Cross-sectional study incorporating adults with SLE genotyped for the CD11B variant R77H and assessed for serum calcification propensity with the T50 method. Participants were included in a multicenter trans-disciplinary cohort and fulfilled the 1997 revised American College of Rheumatology (ACR) criteria for SLE. We used descriptive statistics for comparing baseline characteristics and sequential T50 measurements in subjects with the R77H variant vs. WT CD11B. RESULTS Of the 167 patients, 108 (65%) were G/G (WT), 53 (32%) were G/A heterozygous, and 6 (3%) were A/A homozygous for the R77H variant. A/A patients cumulated more ACR criteria upon inclusion (7 ± 2 vs. 5 ± 1 in G/G and G/A; p = 0.02). There were no differences between the groups in terms of global disease activity, kidney involvement, and chronic renal failure. Complement C3 levels were lower in A/A individuals compared to others (0.6 ± 0.08 vs. 0.9 ± 0.25 g/L; p = 0.02). Baseline T50 did not differ between the groups (A/A 278 ± 42' vs. 297 ± 50' in G/G and G/A; p = 0.28). Considering all sequential T50 test results, serum calcification propensity was significantly increased in A/A individuals compared to others (253 ± 50 vs. 290 ± 54; p = 0.008). CONCLUSIONS SLE patients with homozygosity for the R77H variant and repeated T50 assessment displayed an increased serum calcification propensity (i.e., a lower T50) and lower C3 levels compared to heterozygous and WT CD11B, without differing with respect to global disease activity and kidney involvement. This suggests an increased CV risk in SLE patients homozygous for the R77H variant of CD11B.
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Affiliation(s)
- Matthieu Halfon
- Transplantation Center, Lausanne University Hospital, 1010 Lausanne, Switzerland
| | - Li Zhang
- Department of Physiology, Center for Vascular and Inflammatory Diseases, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Driss Ehirchiou
- Service of Rheumatology, Department of Musculoskeletal Medicine, Lausanne University Hospital, University of Lausanne, 1010 Lausanne, Switzerland
| | - Vishnuprabu Durairaj Pandian
- Department of Physiology, Center for Vascular and Inflammatory Diseases, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Suzan Dahdal
- Division of Nephrology and Hypertension, University Hospital Bern Inselspital, 3010 Bern, Switzerland
| | - Uyen Huynh-Do
- Division of Nephrology and Hypertension, University Hospital Bern Inselspital, 3010 Bern, Switzerland
- Swiss Systemic Lupus Erythematosus Cohort Study
| | - Andreas Pasch
- Department of Physiology and Pathophysiology, Linz University, 4040 Linz, Austria
| | - Camillo Ribi
- Swiss Systemic Lupus Erythematosus Cohort Study
- Division of Immunology and Allergy, Department of Medicine, Lausanne University Hospital, University of Lausanne, 1010 Lausanne, Switzerland
| | - Nathalie Busso
- Service of Rheumatology, Department of Musculoskeletal Medicine, Lausanne University Hospital, University of Lausanne, 1010 Lausanne, Switzerland
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Nording H, Baron L, Langer HF. Platelets as therapeutic targets to prevent atherosclerosis. Atherosclerosis 2020; 307:97-108. [DOI: 10.1016/j.atherosclerosis.2020.05.018] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Revised: 04/30/2020] [Accepted: 05/27/2020] [Indexed: 12/11/2022]
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Chen JY, Cortes C, Ferreira VP. Properdin: A multifaceted molecule involved in inflammation and diseases. Mol Immunol 2018; 102:58-72. [PMID: 29954621 DOI: 10.1016/j.molimm.2018.05.018] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Revised: 05/16/2018] [Accepted: 05/23/2018] [Indexed: 01/17/2023]
Abstract
Properdin, the widely known positive regulator of the alternative pathway (AP), has undergone significant investigation over the last decade to define its function in inflammation and disease, including its role in arthritis, asthma, and kidney and cardiovascular diseases. Properdin is a glycoprotein found in plasma that is mainly produced by leukocytes and can positively regulate AP activity by stabilizing C3 and C5 convertases and initiating the AP. Promotion of complement activity by properdin results in changes in the cellular microenvironment that contribute to innate and adaptive immune responses, including pro-inflammatory cytokine production, immune cell infiltration, antigen presenting cell maturation, and tissue damage. The use of properdin-deficient mouse models and neutralizing antibodies has contributed to the understanding of the mechanisms by which properdin contributes to promoting or preventing disease pathology. This review mainly focusses on the multifaceted roles of properdin in inflammation and diseases, and how understanding these roles is contributing to the development of new disease therapies.
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Affiliation(s)
- Jin Y Chen
- Department of Medical Microbiology and Immunology, University of Toledo College of Medicine and Life Sciences, Toledo, OH, United States.
| | - Claudio Cortes
- Department of Biomedical Sciences, University of Oakland University School of Medicine, Rochester, MI, United States.
| | - Viviana P Ferreira
- Department of Medical Microbiology and Immunology, University of Toledo College of Medicine and Life Sciences, Toledo, OH, United States.
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Hertle E, Arts ICW, Kallen CJHVD, Feskens EJM, Schalkwijk CG, Stehouwer CDA, Greevenbroek MMJV. The alternative complement pathway is longitudinally associated with adverse cardiovascular outcomes. Thromb Haemost 2017; 115:446-57. [DOI: 10.1160/th15-05-0439] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Accepted: 09/08/2015] [Indexed: 01/01/2023]
Abstract
SummaryThe alternative pathway of complement activation is highly reactive and can be activated spontaneously in the vasculature. Activation may contribute to vascular damage and development of cardiovascular disease (CVD). We aimed to investigate functional components of the alternative pathway in cardiovascular risk. We studied 573 individuals who were followed-up for seven years. At baseline, we measured the enhancer properdin; the rate-limiting protease factor D (FD); and a marker of systemic activation, Bb. Using generalised estimating equations, we investigated their longitudinal associations with cardiovascular events (CVE, N=89), CVD (N=159), low-grade inflammation (LGI), endothelial dysfunction (ED) and carotid intima-media thickness (cIMT). Furthermore, we investigated associations with incident CVE (N=39) and CVD (N=73) in 342 participants free of CVD at baseline. CVE included myocardial infarction, stroke, cardiac angioplasty and/or cardiac bypass. CVD additionally included ischaemia on an electrocardiogram and/or ankle-brachial index < 0.9. In adjusted analyses, properdin was positively associated with CVE (per 1SD, longitudinal OR=1.36 [1.07; 1.74], OR for incident CVE=1.53 [1.06; 2.20]), but not with CVD. Properdin was also positively associated with ED (β=0.13 [95 %CI 0.06; 0.20]), but not with LGI or cIMT. FD and Bb were positively associated with LGI (per 1SD, FD: β=0.21 [0.12; 0.29], Bb: β=0.14 [0.07; 0.21]), and ED (FD: β=0.20 [0.11; 0.29], Bb: β=0.10 [0.03; 0.18]), but not with cIMT, CVE or CVD. Taken together, this suggests that the alternative complement pathway contributes to processes of vascular damage, and that in particular a high potential to enhance alternative pathway activation may promote unfavourable cardiovascular outcomes in humans.Supplementary Material to this article is available online at www.thrombosis-online.com.
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Blatt AZ, Pathan S, Ferreira VP. Properdin: a tightly regulated critical inflammatory modulator. Immunol Rev 2017; 274:172-190. [PMID: 27782331 PMCID: PMC5096056 DOI: 10.1111/imr.12466] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The complement alternative pathway is a powerful arm of the innate immune system that enhances diverse inflammatory responses in the human host. Key to the effects of the alternative pathway is properdin, a serum glycoprotein that can both initiate and positively regulate alternative pathway activity. Properdin is produced by many different leukocyte subsets and circulates as cyclic oligomers of monomeric subunits. While the formation of non‐physiological aggregates in purified properdin preparations and the presence of potential properdin inhibitors in serum have complicated studies of its function, properdin has, regardless, emerged as a key player in various inflammatory disease models. Here, we review basic properdin biology, emphasizing the major hurdles that have complicated the interpretation of results from properdin‐centered studies. In addition, we elaborate on an emerging role for properdin in thromboinflammation and discuss the potential utility of properdin inhibitors as long‐term therapeutic options to treat diseases marked by increased formation of platelet/granulocyte aggregates. Finally, we describe the interplay between properdin and the alternative pathway negative regulator, Factor H, and how aiming to understand these interactions can provide scientists with the most effective ways to manipulate alternative pathway activation in complex systems.
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Affiliation(s)
- Adam Z Blatt
- Department of Medical Microbiology and Immunology, University of Toledo College of Medicine and Life Sciences, Toledo, OH, USA
| | - Sabina Pathan
- Department of Medical Microbiology and Immunology, University of Toledo College of Medicine and Life Sciences, Toledo, OH, USA
| | - Viviana P Ferreira
- Department of Medical Microbiology and Immunology, University of Toledo College of Medicine and Life Sciences, Toledo, OH, USA.
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Wiegner R, Chakraborty S, Huber-Lang M. Complement-coagulation crosstalk on cellular and artificial surfaces. Immunobiology 2016; 221:1073-9. [PMID: 27371975 DOI: 10.1016/j.imbio.2016.06.005] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2016] [Revised: 06/02/2016] [Accepted: 06/09/2016] [Indexed: 12/13/2022]
Abstract
The humoral serine proteases of the complement system and the coagulation system play central roles during the events of an inflammatory response. While the complement system confers immunoprotective and -regulatory functions, the coagulation cascade is responsible to ensure hemostatic maintenance. Although these two systems individually unfold during inflammation, several studies have reported on the "crosstalk" between components of the complement and the coagulation system in the fluid phase. However, both cascades are usually initiated on or in close proximity to foreign or activated surfaces, and there is increasing evidence for interacting complement and coagulation proteins on various superficial areas on endothelium, circulating entities like platelets, leukocytes, microparticles and pathogens, and even on artificial surfaces. This review aims at summarizing these interactions to complete the picture.
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Affiliation(s)
- Rebecca Wiegner
- Department of Orthopedic Trauma, Hand-, Plastic- and Reconstructive Surgery, University Hospital of Ulm, Germany
| | - Shinjini Chakraborty
- Department of Orthopedic Trauma, Hand-, Plastic- and Reconstructive Surgery, University Hospital of Ulm, Germany
| | - Markus Huber-Lang
- Department of Orthopedic Trauma, Hand-, Plastic- and Reconstructive Surgery, University Hospital of Ulm, Germany.
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Blatt AZ, Saggu G, Kulkarni KV, Cortes C, Thurman JM, Ricklin D, Lambris JD, Valenzuela JG, Ferreira VP. Properdin-Mediated C5a Production Enhances Stable Binding of Platelets to Granulocytes in Human Whole Blood. THE JOURNAL OF IMMUNOLOGY 2016; 196:4671-4680. [PMID: 27183616 DOI: 10.4049/jimmunol.1600040] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2016] [Accepted: 03/28/2016] [Indexed: 12/11/2022]
Abstract
Enhanced levels of platelet/granulocyte aggregates (PGAs) are found in patients suffering from many different inflammatory vascular diseases, and their formation in animal models of vascular disease is associated with increased thromboinflammation and worsened outcomes. The complement system, a part of the innate immune system, influences PGA formation, but the mechanisms for its effects are unknown. In this study, we have defined complement-mediated mechanisms that enhance PGA formation in human whole blood stimulated with thrombin receptor-activating peptide (TRAP) using ex vivo flow cytometry assays. We demonstrate that physiological properdin, a positive regulator of complement alternative pathway activity, increases PGA formation when added to TRAP-stimulated blood. All physiological properdin forms increase PGA formation, but properdin tetramers are the most efficient at increasing complement activity and PGA formation. Inhibition of endogenous properdin, either circulating in the blood or produced locally by leukocytes, impairs TRAP-mediated PGA formation to the same level as specific inhibition of either the alternative or classical pathway. Additionally, blocking the interaction of C5a with its cellular receptor prevents properdin-mediated increases in PGA formation. Adding either properdin tetramers or C5a to whole blood increases CD11b expression on granulocytes, and this increase is prevented by blockade of the C5a-C5a receptor axis. Finally, we demonstrate that the effects of properdin on PGA formation are tightly regulated by Factor H. Cumulatively, our data indicate that properdin enhances PGA formation via increased production of C5a, and that inhibition of properdin function has therapeutic potential to limit thromboinflammation in diseases characterized by increased PGA formation.
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Affiliation(s)
- Adam Z Blatt
- Department of Medical Microbiology and Immunology, University of Toledo College of Medicine and Life Sciences, Toledo, Ohio
| | - Gurpanna Saggu
- Department of Medical Microbiology and Immunology, University of Toledo College of Medicine and Life Sciences, Toledo, Ohio
| | - Koustubh V Kulkarni
- Department of Medical Microbiology and Immunology, University of Toledo College of Medicine and Life Sciences, Toledo, Ohio
| | - Claudio Cortes
- Department of Biomedical Sciences, Oakland University William Beaumont School of Medicine, Rochester, Michigan
| | - Joshua M Thurman
- Department of Medicine, University of Colorado School of Medicine, Aurora, Colorado
| | - Daniel Ricklin
- Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - John D Lambris
- Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Jesus G Valenzuela
- Vector Molecular Biology Section, LMVR, National Institute of Allergy and Infectious Diseases, NIH, Rockville, Maryland
| | - Viviana P Ferreira
- Department of Medical Microbiology and Immunology, University of Toledo College of Medicine and Life Sciences, Toledo, Ohio
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Saggu G, Cortes C, Emch HN, Ramirez G, Worth RG, Ferreira VP. Identification of a novel mode of complement activation on stimulated platelets mediated by properdin and C3(H2O). JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2013; 190:6457-67. [PMID: 23677468 PMCID: PMC3784323 DOI: 10.4049/jimmunol.1300610] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Elevated numbers of activated platelets circulate in patients with chronic inflammatory diseases, including atherosclerosis and coronary disease. Activated platelets can activate the complement system. Although complement activation is essential for immune responses and removal of spent cells from circulation, it also contributes to inflammation and thrombosis, especially in patients with defective complement regulation. Proinflammatory activated leukocytes, which interact directly with platelets in response to vascular injury, are among the main sources of properdin, a positive regulator of the alternative pathway. The role of properdin in complement activation on stimulated platelets is unknown. Our data show that physiological forms of human properdin bind directly to human platelets after activation by strong agonists in the absence of C3, and bind nonproportionally to surface CD62P expression. Activation of the alternative pathway on activated platelets occurs when properdin is on the surface and recruits C3b or C3(H2O) to form C3b,Bb or a novel cell-bound C3 convertase [C3(H2O),Bb], which normally is present only in the fluid phase. Alternatively, properdin can be recruited by C3(H2O) on the platelet surface, promoting complement activation. Inhibition of factor H-mediated cell surface complement regulation significantly increases complement deposition on activated platelets with surface properdin. Finally, properdin released by activated neutrophils binds to activated platelets. Altogether, these data suggest novel molecular mechanisms for alternative pathway activation on stimulated platelets that may contribute to localization of inflammation at sites of vascular injury and thrombosis.
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Affiliation(s)
- Gurpanna Saggu
- Department of Medical Microbiology and Immunology, College of Medicine and Life Sciences, University of Toledo, Toledo, OH. 43614
| | - Claudio Cortes
- Department of Medical Microbiology and Immunology, College of Medicine and Life Sciences, University of Toledo, Toledo, OH. 43614
- Department of Molecular Sciences, Medical University of the Americas, Charlestown, Nevis, West Indies
| | - Heather N. Emch
- Department of Medical Microbiology and Immunology, College of Medicine and Life Sciences, University of Toledo, Toledo, OH. 43614
| | - Galia Ramirez
- Department of Medical Microbiology and Immunology, College of Medicine and Life Sciences, University of Toledo, Toledo, OH. 43614
- Department of Preventive Animal Medicine, Faculty of Veterinary Medicine, University of Chile, Santiago, Chile
| | - Randall G. Worth
- Department of Medical Microbiology and Immunology, College of Medicine and Life Sciences, University of Toledo, Toledo, OH. 43614
| | - Viviana P. Ferreira
- Department of Medical Microbiology and Immunology, College of Medicine and Life Sciences, University of Toledo, Toledo, OH. 43614
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Cortes C, Ohtola JA, Saggu G, Ferreira VP. Local release of properdin in the cellular microenvironment: role in pattern recognition and amplification of the alternative pathway of complement. Front Immunol 2013; 3:412. [PMID: 23335922 PMCID: PMC3547370 DOI: 10.3389/fimmu.2012.00412] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2012] [Accepted: 12/18/2012] [Indexed: 12/24/2022] Open
Abstract
Properdin, the only positive regulatory protein of the complement system, acts as both a stabilizer of the alternative pathway (AP) convertases and as a selective pattern recognition molecule of certain microorganisms and host cells (i.e., apoptotic/necrotic cells) by serving as a platform for de novo C3b,Bb assembly. Properdin, a highly positively charged protein, normally exists as cyclic dimers (P(2)), trimers (P(3)), and tetramers (P(4)) of head-to-tail associations of monomeric 53 kDa subunits. While most complement proteins are produced mainly in the liver, properdin is synthesized primarily by various cell types, including neutrophils, monocytes, primary T cells, and shear-stressed endothelial cells resulting in properdin serum levels of 4-25 μg/ml. Multiple inflammatory agonists stimulate the release of properdin from stimulated leukocytes into the cellular microenvironment. Concentrated, focused increases in properdin levels may lead to stabilization and initiation of AP convertases, thus greatly amplifying the complement response to a local stimulus. This review highlights current knowledge related to these properties and discusses the implications of properdin production in a pro-inflammatory microenvironment.
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Affiliation(s)
- Claudio Cortes
- Department of Medical Microbiology and Immunology, College of Medicine and Life Sciences, University of Toledo Toledo, OH, USA ; Department Medical Immunology and Microbiology, Medical University of the Americas West Indies, Nevis
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Platelets, Complement, and Contact Activation: Partners in Inflammation and Thrombosis. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2012; 946:185-205. [DOI: 10.1007/978-1-4614-0106-3_11] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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Native properdin binds to Chlamydia pneumoniae and promotes complement activation. Infect Immun 2010; 79:724-31. [PMID: 21134964 DOI: 10.1128/iai.00980-10] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Activation of complement represents one means of natural resistance to infection from a wide variety of potential pathogens. Recently, properdin, a positive regulator of the alternative pathway of complement, has been shown to bind to surfaces and promote complement activation. Here we studied whether properdin-mediated complement activation occurs on the surface of Chlamydia pneumoniae, an obligate intracellular Gram-negative bacterium that causes 10 to 20% of community-acquired pneumonia. We have determined for the first time that the physiological P₂, P₃, and P₄ forms of human properdin bind to the surface of Chlamydia pneumoniae directly. The binding of these physiological forms accelerates complement activation on the Chlamydia pneumoniae surface, as measured by C3b and C9 deposition. Finally, properdin-depleted serum could not control Chlamydia pneumoniae infection of HEp-2 cells compared with normal human serum. However, after addition of native properdin, the properdin-depleted serum recovered the ability to control the infection. Altogether, our data suggest that properdin is a pattern recognition molecule that plays a role in resistance to Chlamydia infection.
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Native polymeric forms of properdin selectively bind to targets and promote activation of the alternative pathway of complement. Immunobiology 2010; 215:932-40. [PMID: 20382442 DOI: 10.1016/j.imbio.2010.02.002] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2010] [Accepted: 02/06/2010] [Indexed: 12/16/2022]
Abstract
Properdin, a positive regulator of the complement system, has recently been reported to bind to certain pathogenic microorganisms, to early or late apoptotic and necrotic cells, and to particular live human cell lines, thus providing a platform for de novo convertase assembly and complement activation. These studies, with some contradictory results, have been carried out with purified properdin, which forms a series of oligomers of a ∼53,000 Mr subunit, assembling into dimers (P₂), trimers (P₃), tetramers (P₄) and higher forms (P(n)). The P(n) forms have been shown to likely be an artefact of purification that results from procedures including freeze-thawing of properdin. In this study we isolated the individual natural forms of properdin (P₂, P₃, and P₄) and separated them from the P(n) forms present in purified frozen properdin using ion exchange and/or size exclusion chromatography. We analyzed the ability of each form to bind to live or necrotic Jurkat and Raji cells, rabbit erythrocytes (E(R)), and zymosan by FACS analysis. While the unseparated properdin and the purified P(n) forms bound to all the surfaces except E(R), the physiological P₂-P₄ forms specifically bound only to zymosan and to necrotic nucleated cells. Our results indicate that aggregated P(n) present in unseparated properdin may bind non-specifically to some surfaces and should be separated before analysis in order to obtain meaningful results. Finally, we have determined for the first time that the physiological forms of human properdin can selectively recognize surfaces and enhance or promote complement activation, which is in agreement with the reported role for properdin as a complement initiator.
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Horstman LL, Jy W, Ahn YS, Zivadinov R, Maghzi AH, Etemadifar M, Steven Alexander J, Minagar A. Role of platelets in neuroinflammation: a wide-angle perspective. J Neuroinflammation 2010; 7:10. [PMID: 20128908 PMCID: PMC2829540 DOI: 10.1186/1742-2094-7-10] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2009] [Accepted: 02/03/2010] [Indexed: 01/03/2023] Open
Abstract
OBJECTIVES This review summarizes recent developments in platelet biology relevant to neuroinflammatory disorders. Multiple sclerosis (MS) is taken as the "Poster Child" of these disorders but the implications are wide. The role of platelets in inflammation is well appreciated in the cardiovascular and cancer research communities but appears to be relatively neglected in neurological research. ORGANIZATION After a brief introduction to platelets, topics covered include the matrix metalloproteinases, platelet chemokines, cytokines and growth factors, the recent finding of platelet PPAR receptors and Toll-like receptors, complement, bioactive lipids, and other agents/functions likely to be relevant in neuroinflammatory diseases. Each section cites literature linking the topic to areas of active research in MS or other disorders, including especially Alzheimer's disease. CONCLUSION The final section summarizes evidence of platelet involvement in MS. The general conclusion is that platelets may be key players in MS and related disorders, and warrant more attention in neurological research.
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Affiliation(s)
- Lawrence L Horstman
- Wallace Coulter Platelet Laboratory, Division of Hematology and Oncology, Department of Medicine, Miller School of Medicine, University of Miami, Miami, Florida, USA
| | - Wenche Jy
- Wallace Coulter Platelet Laboratory, Division of Hematology and Oncology, Department of Medicine, Miller School of Medicine, University of Miami, Miami, Florida, USA
| | - Yeon S Ahn
- Wallace Coulter Platelet Laboratory, Division of Hematology and Oncology, Department of Medicine, Miller School of Medicine, University of Miami, Miami, Florida, USA
| | - Robert Zivadinov
- Buffalo Neuroimaging Analysis Center, The Jacobs Neurological Institute, Department of Neurology, School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo NY, USA
| | - Amir H Maghzi
- Department of Neurology, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Masoud Etemadifar
- Department of Neurology, Isfahan University of Medical Sciences, Isfahan, Iran
| | - J Steven Alexander
- Department of Cellular and Molecular Physiology, Louisiana State University Health Sciences Center, Shreveport, LA 71130, USA
| | - Alireza Minagar
- Department of Neurology, Louisiana State University Health Sciences Center, Shreveport, LA 71130, USA
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