151
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Kriebel K, Hieke C, Müller-Hilke B, Nakata M, Kreikemeyer B. Oral Biofilms from Symbiotic to Pathogenic Interactions and Associated Disease -Connection of Periodontitis and Rheumatic Arthritis by Peptidylarginine Deiminase. Front Microbiol 2018; 9:53. [PMID: 29441048 PMCID: PMC5797574 DOI: 10.3389/fmicb.2018.00053] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Accepted: 01/10/2018] [Indexed: 12/15/2022] Open
Abstract
A wide range of bacterial species are harbored in the oral cavity, with the resulting complex network of interactions between the microbiome and host contributing to physiological as well as pathological conditions at both local and systemic levels. Bacterial communities inhabit the oral cavity as primary niches in a symbiotic manner and form dental biofilm in a stepwise process. However, excessive formation of biofilm in combination with a corresponding deregulated immune response leads to intra-oral diseases, such as dental caries, gingivitis, and periodontitis. Moreover, oral commensal bacteria, which are classified as so-called “pathobionts” according to a now widely accepted terminology, were recently shown to be present in extra-oral lesions with distinct bacterial species found to be involved in the onset of various pathophysiological conditions, including cancer, atherosclerosis, chronic infective endocarditis, and rheumatoid arthritis. The present review focuses on oral pathobionts as commensal and healthy members of oral biofilms that can turn into initiators of disease. We will shed light on the processes involved in dental biofilm formation and also provide an overview of the interactions of P. gingivalis, as one of the most prominent oral pathobionts, with host cells, including epithelial cells, phagocytes, and dental stem cells present in dental tissues. Notably, a previously unknown interaction of P. gingivalis bacteria with human stem cells that has impact on human immune response is discussed. In addition to this very specific interaction, the present review summarizes current knowledge regarding the immunomodulatory effect of P. gingivalis and other oral pathobionts, members of the oral microbiome, that pave the way for systemic and chronic diseases, thereby showing a link between periodontitis and rheumatoid arthritis.
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Affiliation(s)
- Katja Kriebel
- Institute of Medical Microbiology, Virology and Hygiene, University of Rostock, Rostock, Germany
| | - Cathleen Hieke
- Institute of Medical Microbiology, Virology and Hygiene, University of Rostock, Rostock, Germany
| | | | - Masanobu Nakata
- Department of Oral and Molecular Microbiology, Osaka University Graduate School of Dentistry, Suita-Osaka, Japan
| | - Bernd Kreikemeyer
- Institute of Medical Microbiology, Virology and Hygiene, University of Rostock, Rostock, Germany
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152
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Zhou Y, Mittereder N, Sims GP. Perspective on Protein Arginine Deiminase Activity-Bicarbonate Is a pH-Independent Regulator of Citrullination. Front Immunol 2018; 9:34. [PMID: 29403504 PMCID: PMC5778117 DOI: 10.3389/fimmu.2018.00034] [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: 12/01/2017] [Accepted: 01/04/2018] [Indexed: 01/14/2023] Open
Abstract
Protein citrullination catalyzed by peptidyl arginine deiminase (PADs) is involved in autoimmune disease pathogenesis, especially in rheumatoid arthritis. Calcium is a key regulator of PAD activity, but under normal physiological conditions it remains uncertain how intracellular calcium levels can be raised to sufficiently high levels to activate these enzymes. In pursuit of trying to identify other factors that influence PAD activity, we identified bicarbonate as a potential regulator of PAD activity. We demonstrate that physiological levels of bicarbonate upregulate citrullination by recombinant PAD2/4 and endogenous PADs in neutrophils. The impact of bicarbonate is independent of calcium and pH. Adding bicarbonate to commercial PAD activity kits could increase assay performance and biological relevance. These results suggest that citrullination activity is regulated by multiple factors including calcium and bicarbonate. We also provide commentary on the current understanding of PAD regulation and future perspective of research in this area.
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Affiliation(s)
- Yebin Zhou
- Department of Respiratory, Inflammation, and Autoimmunity, MedImmune LLC, Gaithersburg, MD, United States
| | - Nanette Mittereder
- Department of Respiratory, Inflammation, and Autoimmunity, MedImmune LLC, Gaithersburg, MD, United States
| | - Gary P Sims
- Department of Respiratory, Inflammation, and Autoimmunity, MedImmune LLC, Gaithersburg, MD, United States
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153
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Tao L, Xu M, Liu Y. The total terpenoids of Celastrus orbiculatus (TTC) inhibit NOX-dependent formation of PMA-induced neutrophil extracellular traps (NETs). EUR J INFLAMM 2018. [DOI: 10.1177/2058739218805667] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Previously, we identified that Celastrus orbiculatus, a traditional Chinese herbal medicine, exhibited prominent anti-inflammatory and anti-tumor activities. More recently, the formation of neutrophil extracellular traps (NETs) or NETosis has been recognized as a critical pathological event in the development of inflammatory and autoimmune diseases. The present study is aimed to explore the pharmacological effect of the total terpenoids from the stems of C. orbiculatus (TTC) on NETosis and underlying mechanisms, which may provide fundamental knowledge for future utilization of the Chinese medicine. Human neutrophils were isolated by density gradient centrifugation; lactase dehydrogenase (LDH) assay was used to detect cytotoxic effect of TTC on neutrophils. Moreover, we established phorbol-12-myristate-13-acetate (PMA)-induced NETosis. Quantitative and qualitative study of PMA-induced NET release was labeled by SYTOX™ Green. ROS production was determined by flow cytometry. The neutrophil NADPH oxidase (NOX) activity was assessed by lucigenin chemiluminescence assay, and the phosphorylation of NOX subunit was analyzed by immunoblot assay. TTC (5–80 μg.mL−1) had no predominant neutrophil cytotoxicity after 4 h exposure. PMA (200 ng.mL−1) significantly induced the formation of NETs after 4 h stimulus, whereas TTC dose-dependently (5–80 μg.mL−1) inhibited the process. TTC (40 μg.mL−1) blocked neutrophil elastase (NE) and myeloperoxidase (MPO) translocation from cytoplasm to nucleus and disrupted the formation of NET-associated deoxyribonucleic acid (DNA)–MPO and DNA–NE complexes. Moreover, TTC dose-dependently blocked PMA-mediated ROS production, and inhibited the NOX enzymatic activity of neutrophils upon PMA stimulus for 1 h. Finally, TTC suppressed PMA-induced phosphorylation of NOX subunit p40phox on Thr154 residue. TTC inhibited PMA-induced NOX phosphorylation, thereby suppressing NOX enzymatic activity and ROS generation in neutrophils undergoing NETosis. Consequently, TTC disrupted NETosis in the early stage of NOX-dependent NETs formation, which might serve as a promising anti-inflammatory agent by targeting suicidal NETosis.
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Affiliation(s)
- Li Tao
- College of Medicine, Yangzhou University, Yangzhou, China
- The State Administration of Traditional Chinese Medicine Key Laboratory of Toxic Pathogens-Based Therapeutic Approaches of Gastric Cancer, College of Medicine, Yangzhou University, Yangzhou, China
| | - Min Xu
- College of Medicine, Yangzhou University, Yangzhou, China
- The State Administration of Traditional Chinese Medicine Key Laboratory of Toxic Pathogens-Based Therapeutic Approaches of Gastric Cancer, College of Medicine, Yangzhou University, Yangzhou, China
| | - Yanqing Liu
- College of Medicine, Yangzhou University, Yangzhou, China
- The State Administration of Traditional Chinese Medicine Key Laboratory of Toxic Pathogens-Based Therapeutic Approaches of Gastric Cancer, College of Medicine, Yangzhou University, Yangzhou, China
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154
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Abstract
PURPOSE OF REVIEW Dysregulated citrullination is a key element that drives the production and maintenance of antibodies to citrullinated proteins, a hallmark in rheumatoid arthritis (RA). This article reviews recent literature on the origin of citrullinated antigens in RA. RECENT FINDINGS The study of synovial fluid from patients with RA has provided important insights into the identity of citrullinated proteins that accumulate in the RA joint (the RA citrullinome) and mechanisms that control their generation. SUMMARY Citrullinating enzymes (peptidylarginine deiminases, PADs) are tightly controlled to limit their hyperactivation. Calcium and redox conditions are important regulators of PAD activity. Studies suggest that citrullination is dysregulated both intra- and extracellularly in RA. In neutrophils, host (i.e., perforin and the membrane attack complex) and bacterial (i.e., toxins) pore-forming proteins induce prominent calcium influx, cytolysis, and hyperactivation of PADs. These factors likely drive hypercitrullination in the RA joint and at extraarticular sites of disease initiation, respectively. As oxidizing conditions present in the extracellular environment are known to inactivate PADs, extracellular citrullination in RA probably requires the constant release of active enzymes from dying cells and may be accelerated by autoantibodies that activate PADs.
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Affiliation(s)
- Erika Darrah
- Division of Rheumatology, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Felipe Andrade
- Division of Rheumatology, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
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155
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Konig MF, Abusleme L, Reinholdt J, Palmer RJ, Teles RP, Sampson K, Rosen A, Nigrovic PA, Sokolove J, Giles JT, Moutsopoulos NM, Andrade F. Aggregatibacter actinomycetemcomitans-induced hypercitrullination links periodontal infection to autoimmunity in rheumatoid arthritis. Sci Transl Med 2017; 8:369ra176. [PMID: 27974664 DOI: 10.1126/scitranslmed.aaj1921] [Citation(s) in RCA: 355] [Impact Index Per Article: 50.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2016] [Revised: 09/09/2016] [Accepted: 11/09/2016] [Indexed: 12/16/2022]
Abstract
A bacterial etiology of rheumatoid arthritis (RA) has been suspected since the beginnings of modern germ theory. Recent studies implicate mucosal surfaces as sites of disease initiation. The common occurrence of periodontal dysbiosis in RA suggests that oral pathogens may trigger the production of disease-specific autoantibodies and arthritis in susceptible individuals. We used mass spectrometry to define the microbial composition and antigenic repertoire of gingival crevicular fluid in patients with periodontal disease and healthy controls. Periodontitis was characterized by the presence of citrullinated autoantigens that are primary immune targets in RA. The citrullinome in periodontitis mirrored patterns of hypercitrullination observed in the rheumatoid joint, implicating this mucosal site in RA pathogenesis. Proteomic signatures of several microbial species were detected in hypercitrullinated periodontitis samples. Among these, Aggregatibacter actinomycetemcomitans (Aa), but not other candidate pathogens, induced hypercitrullination in host neutrophils. We identified the pore-forming toxin leukotoxin A (LtxA) as the molecular mechanism by which Aa triggers dysregulated activation of citrullinating enzymes in neutrophils, mimicking membranolytic pathways that sustain autoantigen citrullination in the RA joint. Moreover, LtxA induced changes in neutrophil morphology mimicking extracellular trap formation, thereby releasing the hypercitrullinated cargo. Exposure to leukotoxic Aa strains was confirmed in patients with RA and was associated with both anticitrullinated protein antibodies and rheumatoid factor. The effect of human lymphocyte antigen-DRB1 shared epitope alleles on autoantibody positivity was limited to RA patients who were exposed to Aa These studies identify the periodontal pathogen Aa as a candidate bacterial trigger of autoimmunity in RA.
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Affiliation(s)
- Maximilian F Konig
- Division of Rheumatology, Johns Hopkins University School of Medicine, Baltimore, MD 21224, USA
| | - Loreto Abusleme
- National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD 20892, USA
| | - Jesper Reinholdt
- Department of Biomedicine, Aarhus University, 8000 Aarhus C, Denmark
| | - Robert J Palmer
- National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD 20892, USA
| | - Ricardo P Teles
- Department of Periodontology, School of Dentistry, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.,Department of Applied Oral Sciences, Forsyth Institute, Cambridge, MA 02142, USA
| | - Kevon Sampson
- Division of Rheumatology, Johns Hopkins University School of Medicine, Baltimore, MD 21224, USA
| | - Antony Rosen
- Division of Rheumatology, Johns Hopkins University School of Medicine, Baltimore, MD 21224, USA
| | - Peter A Nigrovic
- Division of Rheumatology, Immunology, and Allergy, Brigham and Women's Hospital, Boston, MA 02115, USA.,Division of Immunology, Boston Children's Hospital, Boston, MA 02115, USA
| | - Jeremy Sokolove
- Division of Immunology and Rheumatology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Jon T Giles
- Division of Rheumatology, College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
| | - Niki M Moutsopoulos
- National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD 20892, USA
| | - Felipe Andrade
- Division of Rheumatology, Johns Hopkins University School of Medicine, Baltimore, MD 21224, USA.
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156
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Azithromycin and Chloramphenicol Diminish Neutrophil Extracellular Traps (NETs) Release. Int J Mol Sci 2017; 18:ijms18122666. [PMID: 29292737 PMCID: PMC5751268 DOI: 10.3390/ijms18122666] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2017] [Revised: 11/25/2017] [Accepted: 12/05/2017] [Indexed: 12/24/2022] Open
Abstract
Neutrophils are one of the first cells to arrive at the site of infection, where they apply several strategies to kill pathogens: degranulation, respiratory burst, phagocytosis, and release of neutrophil extracellular traps (NETs). Antibiotics have an immunomodulating effect, and they can influence the properties of numerous immune cells, including neutrophils. The aim of this study was to investigate the effects of azithromycin and chloramphenicol on degranulation, apoptosis, respiratory burst, and the release of NETs by neutrophils. Neutrophils were isolated from healthy donors by density-gradient centrifugation method and incubated for 1 h with the studied antibiotics at different concentrations (0.5, 10 and 50 μg/mL—azithromycin and 10 and 50 μg/mL—chloramphenicol). Next, NET release was induced by a 3 h incubation with 100 nM phorbol 12-myristate 13-acetate (PMA). Amount of extracellular DNA was quantified by fluorometry, and NETs were visualized by immunofluorescent microscopy. Degranulation, apoptosis and respiratory burst were assessed by flow cytometry. We found that pretreatment of neutrophils with azithromycin and chloramphenicol decreases the release of NETs. Moreover, azithromycin showed a concentration-dependent effect on respiratory burst in neutrophils. Chloramphenicol did not affect degranulation, apoptosis nor respiratory burst. It can be concluded that antibiotics modulate the ability of neutrophils to release NETs influencing human innate immunity.
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157
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The Peptidylarginine Deiminase Inhibitor Cl-Amidine Suppresses Inducible Nitric Oxide Synthase Expression in Dendritic Cells. Int J Mol Sci 2017; 18:ijms18112258. [PMID: 29077055 PMCID: PMC5713228 DOI: 10.3390/ijms18112258] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2017] [Revised: 10/16/2017] [Accepted: 10/17/2017] [Indexed: 02/07/2023] Open
Abstract
The conversion of peptidylarginine into peptidylcitrulline by calcium-dependent peptidylarginine deiminases (PADs) has been implicated in the pathogenesis of a number of diseases, identifying PADs as therapeutic targets for various diseases. The PAD inhibitor Cl-amidine ameliorates the disease course, severity, and clinical manifestation in multiple disease models, and it also modulates dendritic cell (DC) functions such as cytokine production, antigen presentation, and T cell proliferation. The beneficial effects of Cl-amidine make it an attractive compound for PAD-targeting therapeutic strategies in inflammatory diseases. Here, we found that Cl-amidine inhibited nitric oxide (NO) generation in a time- and dose-dependent manner in maturing DCs activated by lipopolysaccharide (LPS). This suppression of NO generation was independent of changes in NO synthase (NOS) enzyme activity levels but was instead dependent on changes in inducible NO synthase (iNOS) transcription and expression levels. Several upstream signaling pathways for iNOS expression, including the mitogen-activated protein kinase, nuclear factor-κB p65 (NF-κB p65), and hypoxia-inducible factor 1 pathways, were not affected by Cl-amidine. By contrast, the LPS-induced signal transducer and the activator of transcription (STAT) phosphorylation and activator protein-1 (AP-1) transcriptional activities (c-Fos, JunD, and phosphorylated c-Jun) were decreased in Cl-amidine-treated DCs. Inhibition of Janus kinase/STAT signaling dramatically suppressed iNOS expression and NO production, whereas AP-1 inhibition had no effect. These results indicate that Cl-amidine-inhibited STAT activation may suppress iNOS expression. Additionally, we found mildly reduced cyclooxygenase-2 expression and prostaglandin E2 production in Cl-amidine-treated DCs. Our findings indicate that Cl-amidine acts as a novel suppressor of iNOS expression, suggesting that Cl-amidine has the potential to ameliorate the effects of excessive iNOS/NO-linked immune responses.
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158
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Shi J, Darrah E, Sims GP, Mustelin T, Sampson K, Konig MF, Bingham CO, Rosen A, Andrade F. Affinity maturation shapes the function of agonistic antibodies to peptidylarginine deiminase type 4 in rheumatoid arthritis. Ann Rheum Dis 2017; 77:141-148. [PMID: 29070531 DOI: 10.1136/annrheumdis-2017-211489] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2017] [Revised: 09/08/2017] [Accepted: 09/09/2017] [Indexed: 12/28/2022]
Abstract
OBJECTIVES The citrullinating enzyme peptidylarginine deiminase type 4 (PAD4) is the target of a polyclonal group of autoantibodies in patients with rheumatoid arthritis (RA). A subgroup of such antibodies, initially identified by cross-reactivity with peptidylarginine deiminase type 3 (PAD3), is strongly associated with progression of radiographic joint damage and interstitial lung disease and has the unique ability to activate PAD4. The features of these antibodies in terms of their T cell-dependent origin, genetic characteristics and effect of individual antibody specificities on PAD4 function remain to be defined. METHODS We used PAD4 tagged with the monomeric fluorescent protein mWasabi to isolate PAD4-specific memory B cells from anti-PAD4 positive patients with RA and applied single cell cloning technologies to obtain monoclonal antibodies. RESULTS Among 44 single B cells, we cloned five antibodies with PAD4-activating properties. Sequence analysis, germline reversion experiments and antigen specificity assays suggested that autoantibodies to PAD4 are not polyreactive and arise from PAD4-reactive precursors. Somatic mutations increase the agonistic activity of these antibodies at low calcium concentrations by facilitating their interaction with structural epitopes that modulate calcium-binding site 5 in PAD4. CONCLUSIONS PAD4-activating antibodies directly amplify a key process in disease pathogenesis, making them unique among other autoantibodies in RA. Understanding the molecular basis for their functionality may inform the design of future PAD4 inhibitors.
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Affiliation(s)
- Jing Shi
- Division of Rheumatology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Erika Darrah
- Division of Rheumatology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Gary P Sims
- Respiratory, Inflammation, and Autoimmunity, MedImmune LLC, Gaithersburg, Maryland, USA
| | - Tomas Mustelin
- Respiratory, Inflammation, and Autoimmunity, MedImmune LLC, Gaithersburg, Maryland, USA
| | - Kevon Sampson
- Division of Rheumatology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Maximilian F Konig
- Division of Rheumatology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Clifton O Bingham
- Division of Rheumatology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Antony Rosen
- Division of Rheumatology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Felipe Andrade
- Division of Rheumatology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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159
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Johnson CJ, Kernien JF, Hoyer AR, Nett JE. Mechanisms involved in the triggering of neutrophil extracellular traps (NETs) by Candida glabrata during planktonic and biofilm growth. Sci Rep 2017; 7:13065. [PMID: 29026191 PMCID: PMC5638821 DOI: 10.1038/s41598-017-13588-6] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2017] [Accepted: 09/25/2017] [Indexed: 12/14/2022] Open
Abstract
Candida spp. adhere to medical devices, such as catheters, forming drug-tolerant biofilms that resist killing by the immune system. Little is known about how C. glabrata, an emerging pathogen, resists attack by phagocytes. Here we show that upon encounter with planktonic (non-biofilm) C. glabrata, human neutrophils initially phagocytose the yeast and subsequently release neutrophil extracellular traps (NETs), complexes of DNA, histones, and proteins capable of inhibiting fungal growth and dissemination. When exposed to C. glabrata biofilms, neutrophils also release NETs, but significantly fewer than in response to planktonic cells. Impaired killing of biofilm parallels the decrease in NET production. Compared to biofilm, neutrophils generate higher levels of reactive oxygen species (ROS) when presented with planktonic organisms, and pharmacologic inhibition of NADPH-oxidase partially impairs NET production. In contrast, inhibition of phagocytosis nearly completely blocks NET release to both biofilm and planktonic organisms. Imaging of the host response to C. glabrata in a rat vascular model of infection supports a role for NET release in vivo. Taken together, these findings show that C. glabrata triggers NET release. The diminished NET response to C. glabrata biofilms likely contributes to the resilience of these structured communities to host defenses.
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Affiliation(s)
- Chad J Johnson
- Department of Medicine, University of Wisconsin, Madison, WI, United States of America
| | - John F Kernien
- Department of Medicine, University of Wisconsin, Madison, WI, United States of America
| | - Amanda R Hoyer
- Department of Medicine, University of Wisconsin, Madison, WI, United States of America
| | - Jeniel E Nett
- Department of Medicine, University of Wisconsin, Madison, WI, United States of America. .,Department of Medical Microbiology and Immunology, University of Wisconsin, Madison, WI, United States of America.
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160
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Damgaard D, Bjørn ME, Jensen PØ, Nielsen CH. Reactive oxygen species inhibit catalytic activity of peptidylarginine deiminase. J Enzyme Inhib Med Chem 2017; 32:1203-1208. [PMID: 28933232 PMCID: PMC6021033 DOI: 10.1080/14756366.2017.1368505] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
Protein citrullination catalysed by peptidylarginine deiminase (PAD) may play an important pathogenic role in several chronic inflammatory diseases and malignancies. PAD2, PAD4, and citrullinated proteins are found in the synovium of rheumatoid arthritis patients. PAD activity is dependent on calcium and reducing conditions. However, reactive oxygen species (ROS) have been shown to induce citrullination of histones in granulocytes. Here we examine the ability of H2O2 and leukocyte-derived ROS to regulate PAD activity using citrullination of fibrinogen as read-out. H2O2 at concentrations above 40 µM inhibited the catalytic activity of PAD2 and PAD4 in a dose-dependent manner. PMA-stimulated leukocytes citrullinated fibrinogen and this citrullination was markedly enhanced when ROS formation was inhibited by the NADPH oxidase inhibitor diphenyleneiodonium (DPI). In contrast, PAD released from stimulated leukocytes was unaffected by exogenously added H2O2 at concentrations up to 1000 µM. The role of ROS in regulating PAD activity may play an important part in preventing hypercitrullination of proteins.
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Affiliation(s)
- Dres Damgaard
- a Institute for Inflammation Research, Center for Rheumatology and Spine Diseases, Copenhagen University Hospital, Rigshospitalet , Copenhagen , Denmark.,b Section for Periodontology, Microbiology and Community Dentistry, Department of Odontology, Faculty of Health and Medical Sciences , University of Copenhagen , Copenhagen , Denmark
| | - Mads Emil Bjørn
- a Institute for Inflammation Research, Center for Rheumatology and Spine Diseases, Copenhagen University Hospital, Rigshospitalet , Copenhagen , Denmark.,c Department of Haematology , Roskilde Hospital , Roskilde , Denmark
| | - Peter Østrup Jensen
- a Institute for Inflammation Research, Center for Rheumatology and Spine Diseases, Copenhagen University Hospital, Rigshospitalet , Copenhagen , Denmark.,d Department of Clinical Microbiology , Copenhagen University Hospital, Rigshospitalet , Copenhagen , Denmark
| | - Claus Henrik Nielsen
- a Institute for Inflammation Research, Center for Rheumatology and Spine Diseases, Copenhagen University Hospital, Rigshospitalet , Copenhagen , Denmark.,b Section for Periodontology, Microbiology and Community Dentistry, Department of Odontology, Faculty of Health and Medical Sciences , University of Copenhagen , Copenhagen , Denmark
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161
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Abstract
Neutrophils are innate immune phagocytes that have a central role in immune defence. Our understanding of the role of neutrophils in pathogen clearance, immune regulation and disease pathology has advanced dramatically in recent years. Web-like chromatin structures known as neutrophil extracellular traps (NETs) have been at the forefront of this renewed interest in neutrophil biology. The identification of molecules that modulate the release of NETs has helped to refine our view of the role of NETs in immune protection, inflammatory and autoimmune diseases and cancer. Here, I discuss the key findings and concepts that have thus far shaped the field of NET biology.
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162
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Zhou Y, Chen B, Mittereder N, Chaerkady R, Strain M, An LL, Rahman S, Ma W, Low CP, Chan D, Neal F, Bingham CO, Sampson K, Darrah E, Siegel RM, Hasni S, Andrade F, Vousden KA, Mustelin T, Sims GP. Spontaneous Secretion of the Citrullination Enzyme PAD2 and Cell Surface Exposure of PAD4 by Neutrophils. Front Immunol 2017; 8:1200. [PMID: 28993780 PMCID: PMC5622307 DOI: 10.3389/fimmu.2017.01200] [Citation(s) in RCA: 78] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Accepted: 09/11/2017] [Indexed: 01/08/2023] Open
Abstract
Autoantibodies directed against citrullinated epitopes of proteins are highly diagnostic of rheumatoid arthritis (RA), and elevated levels of protein citrullination can be found in the joints of patients with RA. Calcium-dependent peptidyl-arginine deiminases (PAD) are the enzymes responsible for citrullination. PAD2 and PAD4 are enriched in neutrophils and likely drive citrullination under inflammatory conditions. PADs may be released during NETosis or cell death, but the mechanisms responsible for PAD activity under physiological conditions have not been fully elucidated. To understand how PADs citrullinate extracellular proteins, we investigated the cellular localization and activity of PAD2 and PAD4, and we report that viable neutrophils from healthy donors have active PAD4 exposed on their surface and spontaneously secrete PAD2. Neutrophil activation by some stimulatory agents increased the levels of immunoreactive PAD4 on the cell surface, and some stimuli reduced PAD2 secretion. Our data indicate that live neutrophils have the inherent capacity to express active extracellular PADs. These novel pathways are distinguished from intracellular PAD activation during NETosis and calcium influx-mediated hypercitrullination. Our study implies that extracellular PADs may have a physiological role under non-pathogenic conditions as well as a pathological role in RA.
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Affiliation(s)
- Yebin Zhou
- Department of Respiratory, Inflammation, and Autoimmunity, MedImmune LLC, Gaithersburg, MD, United States
| | - Bo Chen
- Department of Respiratory, Inflammation, and Autoimmunity, MedImmune LLC, Gaithersburg, MD, United States
| | - Nanette Mittereder
- Department of Respiratory, Inflammation, and Autoimmunity, MedImmune LLC, Gaithersburg, MD, United States
| | - Raghothama Chaerkady
- Antibody Discovery and Protein Engineering, MedImmune LLC., Gaithersburg, MD, United States
| | - Martin Strain
- Antibody Discovery and Protein Engineering, MedImmune LTD., Cambridge, United Kingdom
| | - Ling-Ling An
- Department of Respiratory, Inflammation, and Autoimmunity, MedImmune LLC, Gaithersburg, MD, United States
| | - Saifur Rahman
- Department of Respiratory, Inflammation, and Autoimmunity, MedImmune LLC, Gaithersburg, MD, United States
| | - Wenting Ma
- Department of Respiratory, Inflammation, and Autoimmunity, MedImmune LLC, Gaithersburg, MD, United States
| | - Choon Pei Low
- Antibody Discovery and Protein Engineering, MedImmune LTD., Cambridge, United Kingdom
| | - Denice Chan
- Antibody Discovery and Protein Engineering, MedImmune LTD., Cambridge, United Kingdom
| | - Frances Neal
- Antibody Discovery and Protein Engineering, MedImmune LTD., Cambridge, United Kingdom
| | - Clifton O Bingham
- Division of Rheumatology, Department of Medicine, School of Medicine, Johns Hopkins University, Baltimore, MD, United States
| | - Kevon Sampson
- Division of Rheumatology, Department of Medicine, School of Medicine, Johns Hopkins University, Baltimore, MD, United States
| | - Erika Darrah
- Division of Rheumatology, Department of Medicine, School of Medicine, Johns Hopkins University, Baltimore, MD, United States
| | - Richard M Siegel
- Immunoregulation Section, Autoimmunity Branch, National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS), NIH, Bethesda, MD, United States
| | - Sarfaraz Hasni
- Office of the Clinical Director, National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS), NIH, Bethesda, MD, United States
| | - Felipe Andrade
- Division of Rheumatology, Department of Medicine, School of Medicine, Johns Hopkins University, Baltimore, MD, United States
| | - Katherine A Vousden
- Antibody Discovery and Protein Engineering, MedImmune LTD., Cambridge, United Kingdom
| | - Tomas Mustelin
- Department of Respiratory, Inflammation, and Autoimmunity, MedImmune LLC, Gaithersburg, MD, United States
| | - Gary P Sims
- Department of Respiratory, Inflammation, and Autoimmunity, MedImmune LLC, Gaithersburg, MD, United States
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163
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Cheng Z, Meade J, Mankia K, Emery P, Devine DA. Periodontal disease and periodontal bacteria as triggers for rheumatoid arthritis. Best Pract Res Clin Rheumatol 2017; 31:19-30. [PMID: 29221594 DOI: 10.1016/j.berh.2017.08.001] [Citation(s) in RCA: 69] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Revised: 06/01/2017] [Accepted: 06/12/2017] [Indexed: 11/17/2022]
Abstract
There is an epidemiological association between periodontitis and rheumatoid arthritis (RA), which is hypothesised to lead to enhanced generation of RA-related autoantibodies that can be detected years before the onset of RA symptoms. Periodontitis is a common dysbiotic disease; tissue damage occurs because the immune system fails to limit both the resident microbial community and the associated local immune response. Certain periodontal bacteria, including Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans, may contribute to RA autoantibody production through direct post-translational modification of proteins or, indirectly, by influencing neutrophil-mediated neo-epitope generation. Oral bacteria that invade the blood may also contribute to chronic inflammatory responses and generation of autoantibodies. The putative association between periodontitis and the development of RA raises the potential of finding novel predictive markers of disease and disease progression and for periodontitis treatment to be included in the future as an adjunct to conventional RA immunotherapy or as part of a preventive strategy.
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Affiliation(s)
- Zijian Cheng
- Division of Oral Biology, School of Dentistry, University of Leeds, UK
| | - Josephine Meade
- Division of Oral Biology, School of Dentistry, University of Leeds, UK
| | - Kulveer Mankia
- Leeds Musculoskeletal Biomedical Research Unit, School of Medicine, University of Leeds, UK
| | - Paul Emery
- Leeds Musculoskeletal Biomedical Research Unit, School of Medicine, University of Leeds, UK
| | - Deirdre A Devine
- Division of Oral Biology, School of Dentistry, University of Leeds, UK.
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164
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Pan B, Alam HB, Chong W, Mobley J, Liu B, Deng Q, Liang Y, Wang Y, Chen E, Wang T, Tewari M, Li Y. CitH3: a reliable blood biomarker for diagnosis and treatment of endotoxic shock. Sci Rep 2017; 7:8972. [PMID: 28827548 PMCID: PMC5567134 DOI: 10.1038/s41598-017-09337-4] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Accepted: 07/12/2017] [Indexed: 12/23/2022] Open
Abstract
Current biomarkers for sepsis are limited by their non-specificity, short half-life, and insensitive response to therapy. Recently, we have demonstrated that citrullinated histone H3(CitH3) is released into the blood from neutrophil extracellular traps(NETs) in response to severe infection, and CitH3 may be a potential biomarker for sepsis. In the present study, we found that NET components were released in mouse models of both lipopolysaccharide(LPS)-induced shock (LPSS) and hemorrhagic shock (HS). To further quantify CitH3 in the NETs, we established a CitH3 specific enzyme-linked immunosorbent assay. Circulating CitH3 was found to be elevated only in LPSS but not in HS. Importantly, blood CitH3 was detected 30 minutes after LPS insult, and remained elevated for 24 hours (period of the highest mortality). Treatment of endotoxic mice with YW3-56, a peptidylarginine deiminase-2/4 inhibitor, significantly diminished levels of CitH3 in the blood. Interleukin-1β did not respond to LPS early, and interleukin-1β and interleukin-6 fluctuated although they responded to treatment. Procalcitonin reacted to LPS insult late. Compared to CitH3, these biomarkers were non-specifically induced in LPSS and HS. Collectively, our results demonstrate that YW3-56 protects animals from LPSS, and CitH3 is a reliable biomarker due to its early appearance, specificity, duration, and response to therapeutic intervention.
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Affiliation(s)
- Baihong Pan
- Department of General Surgery, Xiangya Hospital, Changsha, Hunan, China.,Department of Surgery, University of Michigan Hospital, Ann Arbor, MI, USA
| | - Hasan B Alam
- Department of Surgery, University of Michigan Hospital, Ann Arbor, MI, USA
| | - Wei Chong
- The First Hospital, China Medical University, Shenyang, China
| | | | - Baoling Liu
- Department of Surgery, University of Michigan Hospital, Ann Arbor, MI, USA
| | - Qiufang Deng
- Department of General Surgery, Xiangya Hospital, Changsha, Hunan, China.,Department of Surgery, University of Michigan Hospital, Ann Arbor, MI, USA
| | - Yinjian Liang
- Department of Surgery, University of Michigan Hospital, Ann Arbor, MI, USA.,The First Hospital, China Medical University, Shenyang, China
| | - Yanming Wang
- Department of Biochemistry and Molecular Biology, Penn State University, University Park, PA, USA
| | - Eric Chen
- Department of Surgery, University of Michigan Hospital, Ann Arbor, MI, USA
| | - Tianbing Wang
- Department of Trauma and Orthopedic Surgery, Peking University People's Hospital, Beijing, China
| | - Muneesh Tewari
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA
| | - Yongqing Li
- Department of Surgery, University of Michigan Hospital, Ann Arbor, MI, USA.
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165
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Qi H, Yang S, Zhang L. Neutrophil Extracellular Traps and Endothelial Dysfunction in Atherosclerosis and Thrombosis. Front Immunol 2017; 8:928. [PMID: 28824648 PMCID: PMC5545592 DOI: 10.3389/fimmu.2017.00928] [Citation(s) in RCA: 109] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2017] [Accepted: 07/20/2017] [Indexed: 12/23/2022] Open
Abstract
Cardiovascular diseases are a leading cause of mortality and morbidity worldwide. Neutrophils are a component of the innate immune system which protect against pathogen invasion; however, the contribution of neutrophils to cardiovascular disease has been underestimated, despite infiltration of leukocyte subsets being a known driving force of atherosclerosis and thrombosis. In addition to their function as phagocytes, neutrophils can release their extracellular chromatin, nuclear protein, and serine proteases to form net-like fiber structures, termed neutrophil extracellular traps (NETs). NETs can entrap pathogens, induce endothelial activation, and trigger coagulation, and have been detected in atherosclerotic and thrombotic lesions in both humans and mice. Moreover, NETs can induce endothelial dysfunction and trigger proinflammatory immune responses. Overall, current data indicate that NETs are not only present in plaques and thrombi but also have causative roles in triggering formation of atherosclerotic plaques and venous thrombi. This review is focused on published findings regarding NET-associated endothelial dysfunction during atherosclerosis, atherothrombosis, and venous thrombosis pathogenesis. The NET structure is a novel discovery that will find its appropriate place in our new understanding of cardiovascular disease. In addition, NETs have high potential to be further explored toward much better treatment of atherosclerosis and venous thromboembolism in clinic.
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Affiliation(s)
- Haozhe Qi
- Department of Vascular Surgery, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Shuofei Yang
- Department of Vascular Surgery, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Lan Zhang
- Department of Vascular Surgery, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
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166
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Kenny EF, Herzig A, Krüger R, Muth A, Mondal S, Thompson PR, Brinkmann V, Bernuth HV, Zychlinsky A. Diverse stimuli engage different neutrophil extracellular trap pathways. eLife 2017; 6. [PMID: 28574339 PMCID: PMC5496738 DOI: 10.7554/elife.24437] [Citation(s) in RCA: 507] [Impact Index Per Article: 72.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Accepted: 06/01/2017] [Indexed: 12/13/2022] Open
Abstract
Neutrophils release neutrophil extracellular traps (NETs) which ensnare pathogens and have pathogenic functions in diverse diseases. We examined the NETosis pathways induced by five stimuli; PMA, the calcium ionophore A23187, nigericin, Candida albicans and Group B Streptococcus. We studied NET production in neutrophils from healthy donors with inhibitors of molecules crucial to PMA-induced NETs including protein kinase C, calcium, reactive oxygen species, the enzymes myeloperoxidase (MPO) and neutrophil elastase. Additionally, neutrophils from chronic granulomatous disease patients, carrying mutations in the NADPH oxidase complex or a MPO-deficient patient were examined. We show that PMA, C. albicans and GBS use a related pathway for NET induction, whereas ionophores require an alternative pathway but that NETs produced by all stimuli are proteolytically active, kill bacteria and composed mainly of chromosomal DNA. Thus, we demonstrate that NETosis occurs through several signalling mechanisms, suggesting that extrusion of NETs is important in host defence. DOI:http://dx.doi.org/10.7554/eLife.24437.001 The immune system protects the body against microorganisms that can cause infections and diseases. Neutrophils are a type of immune cell that patrol the blood in search of germs. Once they encounter potentially harmful microbes, neutrophils eradicate them in different ways. One way to catch the germs is by using ‘neutrophil extracellular traps’, or NETs for short, to confine and kill the invaders. NETs are web-like structures made up of anti-microbial proteins and the neutrophil’s own DNA. The process of making NETs kills the neutrophil, as it eventually explodes to release the NETs. NETs play a key role in disease prevention, but producing too many NETs or producing them at the wrong time or in the wrong place can actually make certain diseases worse. Therefore, it is important to fully understand the signaling pathways and molecules the neutrophils use to make NETs. Kenny et al. exposed neutrophils from healthy people to five different compounds known to cause the cells to make NETs, including some harmful molecules, a fungus and a bacterium. Microscopy was then used to count how many neutrophils made NETs in response to each of the five stimuli. Further experiments showed that neutrophils from patients with an immune system disorder produced fewer NETs when stimulated with some of the compounds, while the other stimuli caused neutrophils to produce the same levels of NETs as healthy individuals. Kenny et al. also revealed that neutrophils use several different ways to produce and release NETs, depending on the stimulus used. Some of the ways required reactive oxygen species, such as hydrogen peroxide and enzymes, while others produced NETs without the need for these molecules. Lastly, Kenny et al. showed that the way the cells die after the NET is released is unique from other pathways that are known to kill cells. Future work will aim to identify a single molecule that can block neutrophils from releasing NETs at the wrong time and place, without affecting the important role NETs play in fighting germs. Such a molecule could be developed into a drug for people with diseases like lupus or rheumatoid arthritis, where the release of NETs makes the disease worse not better. DOI:http://dx.doi.org/10.7554/eLife.24437.002
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Affiliation(s)
- Elaine F Kenny
- Department of Cellular Microbiology, Max Planck Institute for Infection Biology, Berlin, Germany
| | - Alf Herzig
- Department of Cellular Microbiology, Max Planck Institute for Infection Biology, Berlin, Germany
| | - Renate Krüger
- Department of Paediatric Pneumology and Immunology, Outpatient Clinic for Primary Immunodeficiencies, Charité Medical School, Berlin, Germany.,Sozialpädiatrisches Zentrum, Charité Medical School, Berlin, Germany
| | - Aaron Muth
- Department of Biochemistry and Pharmacology, University of Massachusetts Medical School, Worcester, United States
| | - Santanu Mondal
- Department of Biochemistry and Pharmacology, University of Massachusetts Medical School, Worcester, United States
| | - Paul R Thompson
- Department of Biochemistry and Pharmacology, University of Massachusetts Medical School, Worcester, United States
| | - Volker Brinkmann
- Microscopy Core Facility, Max Planck Institute for Infection Biology, Berlin, Germany
| | - Horst von Bernuth
- Department of Paediatric Pneumology and Immunology, Outpatient Clinic for Primary Immunodeficiencies, Charité Medical School, Berlin, Germany.,Sozialpädiatrisches Zentrum, Charité Medical School, Berlin, Germany.,Labor Berlin, Section for Immunology, Charité-Vivantes GmbH, Berlin, Germany.,Berlin Centre for Regenerative Therapies, Charité Medical School, Berlin, Germany
| | - Arturo Zychlinsky
- Department of Cellular Microbiology, Max Planck Institute for Infection Biology, Berlin, Germany
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167
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Gordon RA, Herter JM, Rosetti F, Campbell AM, Nishi H, Kashgarian M, Bastacky SI, Marinov A, Nickerson KM, Mayadas TN, Shlomchik MJ. Lupus and proliferative nephritis are PAD4 independent in murine models. JCI Insight 2017; 2:92926. [PMID: 28515361 DOI: 10.1172/jci.insight.92926] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2017] [Accepted: 04/10/2017] [Indexed: 12/21/2022] Open
Abstract
Though recent reports suggest that neutrophil extracellular traps (NETs) are a source of antigenic nucleic acids in systemic lupus erythematosus (SLE), we recently showed that inhibition of NETs by targeting the NADPH oxidase complex via cytochrome b-245, β polypeptide (cybb) deletion exacerbated disease in the MRL.Faslpr lupus mouse model. While these data challenge the paradigm that NETs promote lupus, it is conceivable that global regulatory properties of cybb and cybb-independent NETs confound these findings. Furthermore, recent reports indicate that inhibitors of peptidyl arginine deiminase, type IV (Padi4), a distal mediator of NET formation, improve lupus in murine models. Here, to clarify the contribution of NETs to SLE, we employed a genetic approach to delete Padi4 in the MRL.Faslpr model and used a pharmacological approach to inhibit PADs in both the anti-glomerular basement membrane model of proliferative nephritis and a human-serum-transfer model of SLE. In contrast to prior inhibitor studies, we found that deletion of Padi4 did not ameliorate any aspect of nephritis, loss of tolerance, or immune activation. Pharmacological inhibition of PAD activity had no effect on end-organ damage in inducible models of glomerulonephritis. These data provide a direct challenge to the concept that NETs promote autoimmunity and target organ injury in SLE.
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Affiliation(s)
- Rachael A Gordon
- Department of Immunology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Jan M Herter
- Department of Pathology, Brigham and Women's Hospital, and Harvard Medical School, Boston, Massachusetts, USA
| | - Florencia Rosetti
- Department of Pathology, Brigham and Women's Hospital, and Harvard Medical School, Boston, Massachusetts, USA
| | | | - Hiroshi Nishi
- Department of Pathology, Brigham and Women's Hospital, and Harvard Medical School, Boston, Massachusetts, USA
| | - Michael Kashgarian
- Department of Pathology, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Sheldon I Bastacky
- Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Anthony Marinov
- Department of Immunology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Kevin M Nickerson
- Department of Immunology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Tanya N Mayadas
- Department of Pathology, Brigham and Women's Hospital, and Harvard Medical School, Boston, Massachusetts, USA
| | - Mark J Shlomchik
- Department of Immunology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA.,Department of Immunobiology.,Department of Laboratory Medicine, Yale University School of Medicine, New Haven, Connecticut, USA
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168
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Kienhöfer D, Hahn J, Stoof J, Csepregi JZ, Reinwald C, Urbonaviciute V, Johnsson C, Maueröder C, Podolska MJ, Biermann MH, Leppkes M, Harrer T, Hultqvist M, Olofsson P, Munoz LE, Mocsai A, Herrmann M, Schett G, Holmdahl R, Hoffmann MH. Experimental lupus is aggravated in mouse strains with impaired induction of neutrophil extracellular traps. JCI Insight 2017; 2:92920. [PMID: 28515366 DOI: 10.1172/jci.insight.92920] [Citation(s) in RCA: 100] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2017] [Accepted: 04/10/2017] [Indexed: 11/17/2022] Open
Abstract
Many effector mechanisms of neutrophils have been implicated in the pathogenesis of systemic lupus erythematosus (SLE). Neutrophil extracellular traps (NETs) have been assigned a particularly detrimental role. Here we investigated the functional impact of neutrophils and NETs on a mouse model of lupus triggered by intraperitoneal injection of the cell death-inducing alkane pristane. Pristane-induced lupus (PIL) was aggravated in 2 mouse strains with impaired induction of NET formation, i.e., NOX2-deficient (Ncf1-mutated) and peptidyl arginine deiminase 4-deficient (PAD4-deficient) mice, as seen from elevated levels of antinuclear autoantibodies (ANAs) and exacerbated glomerulonephritis. We observed a dramatically reduced ability to form pristane-induced NETs in vivo in both Ncf1-mutated and PAD4-deficient mice, accompanied by higher levels of inflammatory mediators in the peritoneum. Similarly, neutropenic Mcl-1ΔMyelo mice exhibited higher levels of ANAs, which indicates a regulatory function in lupus of NETs and neutrophils. Blood neutrophils from Ncf1-mutated and human individuals with SLE exhibited exuberant spontaneous NET formation. Treatment with specific chemical NOX2 activators induced NET formation and ameliorated PIL. Our findings suggest that aberrant NET is one of the factors promoting experimental lupus-like autoimmunity by uncontrolled release of inflammatory mediators.
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Affiliation(s)
- Deborah Kienhöfer
- Friedrich-Alexander-University Erlangen-Nürnberg (FAU), Department of Internal Medicine 3 - Rheumatology and Immunology, Universitätsklinikum Erlangen, Erlangen, Germany
| | - Jonas Hahn
- Friedrich-Alexander-University Erlangen-Nürnberg (FAU), Department of Internal Medicine 3 - Rheumatology and Immunology, Universitätsklinikum Erlangen, Erlangen, Germany
| | - Julia Stoof
- Friedrich-Alexander-University Erlangen-Nürnberg (FAU), Department of Internal Medicine 3 - Rheumatology and Immunology, Universitätsklinikum Erlangen, Erlangen, Germany
| | - Janka Zsófia Csepregi
- Friedrich-Alexander-University Erlangen-Nürnberg (FAU), Department of Internal Medicine 1 - Gastroenterology, Pneumology and Endocrinology, Universitätsklinikum Erlangen, Erlangen, Germany
| | - Christiane Reinwald
- Friedrich-Alexander-University Erlangen-Nürnberg (FAU), Department of Internal Medicine 3 - Rheumatology and Immunology, Universitätsklinikum Erlangen, Erlangen, Germany
| | - Vilma Urbonaviciute
- Section of Medical Inflammation Research, Department of Medical Biochemistry and Biophysics, Karolinska Institute, Stockholm, Sweden
| | | | - Christian Maueröder
- Friedrich-Alexander-University Erlangen-Nürnberg (FAU), Department of Internal Medicine 3 - Rheumatology and Immunology, Universitätsklinikum Erlangen, Erlangen, Germany
| | - Malgorzata J Podolska
- Friedrich-Alexander-University Erlangen-Nürnberg (FAU), Department of Internal Medicine 3 - Rheumatology and Immunology, Universitätsklinikum Erlangen, Erlangen, Germany
| | - Mona H Biermann
- Friedrich-Alexander-University Erlangen-Nürnberg (FAU), Department of Internal Medicine 3 - Rheumatology and Immunology, Universitätsklinikum Erlangen, Erlangen, Germany
| | - Moritz Leppkes
- Department of Medicine 1, University of Erlangen-Nuremberg, Erlangen, Germany
| | - Thomas Harrer
- Friedrich-Alexander-University Erlangen-Nürnberg (FAU), Department of Internal Medicine 3 - Rheumatology and Immunology, Universitätsklinikum Erlangen, Erlangen, Germany
| | | | | | - Luis E Munoz
- Friedrich-Alexander-University Erlangen-Nürnberg (FAU), Department of Internal Medicine 3 - Rheumatology and Immunology, Universitätsklinikum Erlangen, Erlangen, Germany
| | - Attila Mocsai
- Friedrich-Alexander-University Erlangen-Nürnberg (FAU), Department of Internal Medicine 1 - Gastroenterology, Pneumology and Endocrinology, Universitätsklinikum Erlangen, Erlangen, Germany
| | - Martin Herrmann
- Friedrich-Alexander-University Erlangen-Nürnberg (FAU), Department of Internal Medicine 3 - Rheumatology and Immunology, Universitätsklinikum Erlangen, Erlangen, Germany
| | - Georg Schett
- Friedrich-Alexander-University Erlangen-Nürnberg (FAU), Department of Internal Medicine 3 - Rheumatology and Immunology, Universitätsklinikum Erlangen, Erlangen, Germany
| | - Rikard Holmdahl
- Friedrich-Alexander-University Erlangen-Nürnberg (FAU), Department of Internal Medicine 1 - Gastroenterology, Pneumology and Endocrinology, Universitätsklinikum Erlangen, Erlangen, Germany
| | - Markus H Hoffmann
- Friedrich-Alexander-University Erlangen-Nürnberg (FAU), Department of Internal Medicine 3 - Rheumatology and Immunology, Universitätsklinikum Erlangen, Erlangen, Germany
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169
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Döring Y, Soehnlein O, Weber C. Neutrophil Extracellular Traps in Atherosclerosis and Atherothrombosis. Circ Res 2017; 120:736-743. [PMID: 28209798 DOI: 10.1161/circresaha.116.309692] [Citation(s) in RCA: 319] [Impact Index Per Article: 45.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Revised: 01/13/2016] [Accepted: 01/16/2016] [Indexed: 12/17/2022]
Abstract
Neutrophil extracellular traps expelled from suicidal neutrophils comprise a complex structure of nuclear chromatin and proteins of nuclear, granular, and cytosolic origin. These net-like structures have also been detected in atherosclerotic lesions and arterial thrombi in humans and mice. Functionally, neutrophil extracellular traps have been shown to induce activation of endothelial cells, antigen-presenting cells, and platelets, resulting in a proinflammatory immune response. Overall, this suggests that they are not only present in plaques and thrombi but also they may play a causative role in triggering atherosclerotic plaque formation and arterial thrombosis. This review will focus on current findings of the involvement of neutrophil extracellular traps in atherogenesis and atherothrombosis.
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Affiliation(s)
- Yvonne Döring
- From the Institute for Cardiovascular Prevention (IPEK), Department of Medicine, LMU Munich, Germany (Y.D., O.S., C.W.); DZHK (German Centre for Cardiovascular Research), partner site Munich Heart Alliance, Germany (O.S., C.W.); Department of Pathology, Academic Medical Center, Amsterdam, The Netherlands (O.S.); and Department of Biochemistry, Cardiovascular Research Institute (CARIM), Maastricht University, The Netherlands (C.W.).
| | - Oliver Soehnlein
- From the Institute for Cardiovascular Prevention (IPEK), Department of Medicine, LMU Munich, Germany (Y.D., O.S., C.W.); DZHK (German Centre for Cardiovascular Research), partner site Munich Heart Alliance, Germany (O.S., C.W.); Department of Pathology, Academic Medical Center, Amsterdam, The Netherlands (O.S.); and Department of Biochemistry, Cardiovascular Research Institute (CARIM), Maastricht University, The Netherlands (C.W.)
| | - Christian Weber
- From the Institute for Cardiovascular Prevention (IPEK), Department of Medicine, LMU Munich, Germany (Y.D., O.S., C.W.); DZHK (German Centre for Cardiovascular Research), partner site Munich Heart Alliance, Germany (O.S., C.W.); Department of Pathology, Academic Medical Center, Amsterdam, The Netherlands (O.S.); and Department of Biochemistry, Cardiovascular Research Institute (CARIM), Maastricht University, The Netherlands (C.W.).
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170
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Dekkers JS, Verheul MK, Stoop JN, Liu B, Ioan-Facsinay A, van Veelen PA, de Ru AH, Janssen GMC, Hegen M, Rapecki S, Huizinga TWJ, Trouw LA, Toes REM. Breach of autoreactive B cell tolerance by post-translationally modified proteins. Ann Rheum Dis 2017; 76:1449-1457. [DOI: 10.1136/annrheumdis-2016-210772] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2016] [Revised: 02/10/2017] [Accepted: 03/23/2017] [Indexed: 02/01/2023]
Abstract
ObjectivesOver 50% of patients with rheumatoid arthritis (RA) harbour a variety of anti-modified protein antibodies (AMPA) against different post-translationally modified (PTM) proteins, including anti-carbamylated protein (anti-CarP) antibodies. At present, it is unknown how AMPA are generated and how autoreactive B cell responses against PTM proteins are induced. Here we studied whether PTM foreign antigens can breach B cell tolerance towards PTM self-proteins.MethodsSerum reactivity towards five carbamylated proteins was determined for 160 patients with RA and 40 healthy individuals. Antibody cross-reactivity was studied by inhibition experiments. Mass spectrometry was performed to identify carbamylated self-proteins in human rheumatic joint tissue. Mice were immunised with carbamylated or non-modified (auto)antigens and analysed for autoantibody responses.ResultsWe show that anti-CarP antibodies in RA are highly cross-reactive towards multiple carbamylated proteins, including modified self-proteins and modified non-self-proteins. Studies in mice show that anti-CarP antibody responses recognising carbamylated self-proteins are induced by immunisation with carbamylated self-proteins and by immunisation with carbamylated proteins of non-self-origin. Similar to the data observed with sera from patients with RA, the murine anti-CarP antibody response was, both at the monoclonal level and the polyclonal level, highly cross-reactive towards multiple carbamylated proteins, including carbamylated self-proteins.ConclusionsSelf-reactive AMPA responses can be induced by exposure to foreign proteins containing PTM. These data show how autoreactive B cell responses against PTM self-proteins can be induced by exposure to PTM foreign proteins and provide new insights on the breach of autoreactive B cell tolerance.
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