scholarly journals Insight into Neutrophil Extracellular Traps through Systematic Evaluation of Citrullination and Peptidylarginine Deiminases

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Caitlyn L. Holmes ◽  
Daeun Shim ◽  
John Kernien ◽  
Chad J. Johnson ◽  
Jeniel E. Nett ◽  
...  
Keyword(s):  
Rheumatoid Arthritis ◽  
Neutrophil Extracellular Traps ◽  
Systematic Evaluation ◽  
Peptidylarginine Deiminase ◽  
Monosodium Urate ◽  
Extracellular Traps ◽  
Different Types ◽  
Citrullinated Proteins ◽  
Insight Into

In rheumatoid arthritis, an autoimmune inflammatory arthritis, citrullinated proteins are targeted by autoantibodies and thus thought to drive disease. Neutrophil extracellular traps (NETs) are a source of citrullinated proteins and are increased in rheumatoid arthritis and therefore also implicated in disease pathogenesis. However, not all NETs are citrullinated. One theory aiming to clarify the intersection of citrullination, NETs, and rheumatoid arthritis suggests that specific stimuli induce different types of NETs defined by citrullination status. However, most studies do not evaluate uncitrullinated NETs, only citrullinated or total NETs. Further, the requirement for peptidylarginine deiminase (PAD) 2 and 4, two important citrullinating enzymes in neutrophils and rheumatoid arthritis, in the formation of different NETs has not been clearly defined. To determine if specific stimulants induce citrullinated or uncitrullinated NETs and if those structures require PAD2 or PAD4, human and murine neutrophils, including from PAD4-/- and PAD2-/- mice, were stimulated in vitro and NETs imaged and quantified. In humans, phorbol myristate acetate (PMA), ionomycin, monosodium urate (MSU), and Candida albicans induced NETs with MSU and C. albicans inducing primarily citrullinated, PMA primarily uncitrullinated, and ionomycin a mix of NETs. Only ionomycin and C. albicans were strong inducers of NETs in mice with ionomycin-induced NETs mostly citrullinated and C. albicans-induced NETs a mix of citrullinated and uncitrullinated. Interestingly, no stimulus induced exclusively citrullinated or uncitrullinated NETs. Further, PAD4 was required for citrullinated NETs only, whereas PAD2 was not required for either NET in mice. Therefore, specific stimuli induce varying proportions of both citrullinated and uncitrullinated NETs with different requirements for PAD4. These findings highlight the complexity of NET formation and the need to further define the mechanisms by which different NETs form and their implications for autoimmune disease.

scholarly journals S100A11 (calgizzarin) is released via NETosis in rheumatoid arthritis (RA) and stimulates IL-6 and TNF secretion by neutrophils

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Adéla Navrátilová ◽  
Viktor Bečvář ◽  
Jiří Baloun ◽  
Dres Damgaard ◽  
Claus Henrik Nielsen ◽  
...  
Keyword(s):  
Rheumatoid Arthritis ◽  
Synovial Fluid ◽  
Synovial Tissue ◽  
Neutrophil Extracellular Traps ◽  
S100 Family ◽  
Extracellular Traps ◽  
Associated Proteins ◽  
First Time ◽  
Pro Inflammatory Cytokines

AbstractS100A11 (calgizzarin), a member of S100 family, is associated with several autoimmune diseases, including rheumatoid arthritis (RA). Neutrophil extracellular traps (NETs) are implicated in the pathogenesis of RA and in the externalization of some S100 family members. Therefore, we aimed to determine the association between S100A11 and NETs in RA. For this purpose, the levels of S100A11 and NETosis markers were detected in the RA synovial fluid by immunoassays. The expression of S100A11 by neutrophils in the RA synovial tissue was assessed. Neutrophils isolated from peripheral blood were exposed to S100A11 or stimulated to release NETs. The levels of NETosis- and inflammation-associated proteins were analysed by immunoassays. NETs were visualized by immunofluorescence. We showed that S100A11 was expressed by the neutrophils in the RA synovial tissue. Moreover, S100A11 in the RA synovial fluid correlated with several NETosis markers. In vitro, S100A11 was abundantly released by neutrophils undergoing NETosis compared to untreated cells (p < 0.001). Extracellular S100A11 increased the secretion of IL-6 (p < 0.05) and TNF (p < 0.05) by neutrophils but did not induce NETosis. This study demonstrates, for the first time, that the release of S100A11 is dependent on NETosis and that extracellular S100A11 augments the inflammatory response by inducing pro-inflammatory cytokines in neutrophils.

scholarly journals Neutrophil Extracellular Traps Induced in Rheumatoid Arthritis Conditioned Animals are Inhibited Through Selenium Nanoparticles Supplementation

2020 ◽  
Author(s):  
Bo Zhang ◽  
Xiao-Xiong Zhao ◽  
Yuan Lin ◽  
Tong Chen ◽  
Ren Shi-Xiang
Keyword(s):  
Rheumatoid Arthritis ◽  
Oxidative Stress ◽  
Human Study ◽  
Neutrophil Extracellular Traps ◽  
The Other ◽  
Antioxidant Enzyme Activities ◽  
Experimental Conditions ◽  
Extracellular Traps ◽  
Other Hand

Abstract Growing experimental evidence shows that the neutrophil extracellular traps (NETs) plays vital contribution in rheumatoid arthritis (RA). Selenium (Se) and Se nanoparticles (SeNPs) known to modulate RA-induced pathogenesis through antioxidant gene modulation. In the present study we have inferred that SeNPs supplementation effectively controls NETs formation, which in turn could curtail RA-induced inflammatory response.Neutrophils obtained from different experimental conditions were used to evaluate the in vitro NETs formation and inhibition of through SeNPs supplementation. Increased oxidative stress, decreased antioxidant enzyme activities and increased inflammatory cytokines were observed in neutrophils of RA, whereas SeNPs treatment attenuate it. Neutrophils obtained from control and SeNPs supplemented groups do not have statistically significant Se level between the groups, on the other hand reduced the oxidative stress. Neutrophils of RA forms more spontaneous NETs in vitro culture than that of control and SeNPs treated neutrophils. Neutrophils obtained from RA rats are more inclined for external NETs inducing agent such as lipopolysaccharides and phorbol 12-myristate 13-acetate, when compared with SeNPs treated and control neutrophils. On the other hand in vitro pre-treatment of neutrophils with SeNPs before exposing to NETs inducing substances, indicate the anti-NETs forming property of SeNPs. This effect could be mediated through reduction in major inflammatory mediators namely TNF-α, IL-17 and IL-6. This findings confirms that SeNPs could act as effective NETs formation blocking agent. Our present and previous observation conclude that SeNPs, could serve as an effective anti-arthritic agent warranting human study. Furthermore, this study also throws light on the new information such as SeNPs which could be used as therapeutics agent, where NETs is major pathogenic factor.

scholarly journals Cytonemes Versus Neutrophil Extracellular Traps in the Fight of Neutrophils with Microbes

2020 ◽  
Vol 21 (2) ◽  
pp. 586 ◽  
Author(s):  
Svetlana I. Galkina ◽  
Natalia V. Fedorova ◽  
Ekaterina A. Golenkina ◽  
Vladimir I. Stadnichuk ◽  
Galina F. Sud’ina
Keyword(s):  
Nitric Oxide ◽  
Membrane Vesicles ◽  
Neutrophil Extracellular Traps ◽  
The Body ◽  
Peptidylarginine Deiminase ◽  
Chromatin Decondensation ◽  
Extracellular Traps ◽  
Dna Strands

Neutrophils can phagocytose microorganisms and destroy them intracellularly using special bactericides located in intracellular granules. Recent evidence suggests that neutrophils can catch and kill pathogens extracellularly using the same bactericidal agents. For this, live neutrophils create a cytoneme network, and dead neutrophils provide chromatin and proteins to form neutrophil extracellular traps (NETs). Cytonemes are filamentous tubulovesicular secretory protrusions of living neutrophils with intact nuclei. Granular bactericides are localized in membrane vesicles and tubules of which cytonemes are composed. NETs are strands of decondensed DNA associated with histones released by died neutrophils. In NETs, bactericidal neutrophilic agents are adsorbed onto DNA strands and are not covered with a membrane. Cytonemes and NETs occupy different places in protecting the body against infections. Cytonemes can develop within a few minutes at the site of infection through the action of nitric oxide or actin-depolymerizing alkaloids of invading microbes. The formation of NET in vitro occurs due to chromatin decondensation resulting from prolonged activation of neutrophils with PMA (phorbol 12-myristate 13-acetate) or other stimuli, or in vivo due to citrullination of histones with peptidylarginine deiminase 4. In addition to antibacterial activity, cytonemes are involved in cell adhesion and communications. NETs play a role in autoimmunity and thrombosis.

scholarly journals THE ROLE OF PLATELETS IN FORMATION OF NEUTROPHIL EXTRACELLULAR TRAPS IN PATIENTS WITH IMMUNOCOMPLEX PATHOLOGY

2016 ◽  
pp. 66-70
Author(s):  
J. V. Zubkova ◽  
I. A. Novikova ◽  
V. V. Zhelezko
Keyword(s):  
Rheumatoid Arthritis ◽  
Systemic Lupus Erythematosus ◽  
Rheumatoid Factor ◽  
Lupus Erythematosus ◽  
Neutrophil Extracellular Traps ◽  
In Vitro Cultures ◽  
Systemic Lupus ◽  
Extracellular Traps

The article presents the results of the assessment of the role of platelets in formation of extracellular traps by neutrophils. We have detected the ability of platelets to oppress the formation of extracellular traps by neutrophils in vitro cultures in patients with rheumatoid arthritis (RA) (n = 42) and systemic lupus erythematosus (SLE) (n = 24), but not in patients with hemorrhagic vasculitis (GW) (n = 15). The study has revealed the interrelation of NETosis and rheumatoid factor in patients with RA and SLE, as well as NET formation and number of platelets in patients with GW.

scholarly journals Neutrophil extracellular traps induce MCP-1 release from endothelial cells at the plaque rupture site in acute myocardial infarction

2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
A Ondracek ◽  
T.M Hofbauer ◽  
A Mangold ◽  
T Scherz ◽  
V Seidl ◽  
...  
Keyword(s):  
Myocardial Infarction ◽  
Acute Myocardial Infarction ◽  
Endothelial Cells ◽  
Plaque Rupture ◽  
Ex Vivo ◽  
Coronary Intervention ◽  
Neutrophil Extracellular Traps ◽  
Funding Source ◽  
Extracellular Traps

Abstract Introduction Leukocyte-mediated inflammation is crucial in acute myocardial infarction (AMI). We recently observed that neutrophil extracellular traps (NETs) are increased at the culprit site, promoting activation and differentiation of fibrocytes, cells with mesenchymal and leukocytic properties. Fibrocyte migration is mediated by monocyte chemoattractant protein (MCP)-1 and C-C chemokine receptor type 2 (CCR2). We investigated the interplay between NETs, fibrocyte function, and MCP-1 in AMI. Methods Culprit site and femoral blood of AMI patients was drawn during percutaneous coronary intervention. We characterized CCR2 expression of fibrocytes by flow cytometry. MCP-1 and the NET marker citrullinated histone H3 (citH3) were measured by ELISA. Fibrocytes were treated in vitro with MCP-1. Human coronary arterial endothelial cells (hCAECs) were stimulated with isolated NETs, and MCP-1 was measured by ELISA and qPCR. The influence of MCP-1 on NET formation in vitro was assessed using isolated neutrophils. Results We have included 50 consecutive AMI patients into the study. NETs and concentrations of MCP-1 were increased at the CLS. NET stimulation of hCAECs induced MCP-1 on mRNA and protein level. Increasing MCP-1 gradient was associated with fibrocyte accumulation at the site of occlusion. In the presence of higher MCP-1 these fibrocytes expressed proportionally less CCR2 than peripheral fibrocytes. In vitro, MCP-1 dose-dependently decreased fibrocyte CCR2 and reduced ex vivo NET release of healthy donor neutrophils. Conclusions NETs induce endothelial MCP-1 release, presumably promoting a chemotactic gradient for leukocyte and fibrocyte migration. MCP-1 mediated inhibition of NET formation could point to a negative feedback loop. These data will shed light on vascular healing. Funding Acknowledgement Type of funding source: Public grant(s) – National budget only. Main funding source(s): Austrian Science Fund

755 CXCR1 and CXCR2 chemokine receptor agonists produced by tumors induce neutrophil extracellular traps that interfere with immune cytotoxicity

2020 ◽  
Vol 8 (Suppl 3) ◽  
pp. A803-A803 ◽  
Author(s):  
Alvaro Teijeira ◽  
Saray Garasa ◽  
Itziar Migueliz ◽  
Assunta Cirella ◽  
Ignacio Melero
Keyword(s):  
Cancer Patients ◽  
Tumor Cells ◽  
Mouse Models ◽  
Chemokine Receptor ◽  
Suppressor Cells ◽  
Neutrophil Extracellular Traps ◽  
Myeloid Derived Suppressor Cells ◽  
Extracellular Traps ◽  
Tumor Associated Neutrophils

BackgroundNeutrophils are expanded and abundant in an important fraction (up to 35% of patients) in cancer-bearing hosts. When neutrophils are expanded, they usually promote exert immunomodulatory functions promoting tumor progression and the generation of metastases. Neutrophils can undergo a specialized form of cell death called NETosis that is characterized by the extrusion of their DNA to contain infections. In cancer NETs have been described to promote metastases in mouse models. IL-8, a CXCR1/2 ligand clinically targeted by blocking antibodies, has been described to induce NETosis and is upregulated in many cancer patients. Our hypothesis is that chemokines secreted by cancer cells can mediate NETosis in tumor associated neutrophils and that NETs can be one of the immunomodulatory mechanisms provided by tumor associated neutrophils.MethodsNETosis induction of peripheral neutrophils and granulocytic myeloid derived suppressor cells by different chemotactic stimuli, tumor cell supernatants and cocultures upon CXCR1/2 blockade. NET immunodetection in mouse models and xenograft tumors upon CXCR1/2 blockade. In vitro tumor cytotoxicity assays in the presence/absence of NETs, and videomicroscopy studies in vitro and by intravital imaging to test NETs inhibition of immune cytotoxicity by immune-cell/target-cell inhibition. Tumor growth studies and metastases models in the presence of NETosis inhibitors and in combination with checkpoint blockade in mouse cancer models.ResultsUnder the influence of CXCR1 and CXCR2 chemokine receptor agonists and other chemotactic factors produced by tumors, neutrophils, and granulocytic myeloid-derived suppressor cells (MDSCs) from cancer patients extrude their neutrophil extracellular traps (NETs). In our hands, CXCR1 and CXCR2 agonists proved to be the major mediators of cancer-promoted NETosis. NETs wrap and coat tumor cells and shield them from cytotoxicity, as mediated by CD8+ T cells and natural killer (NK) cells, by obstructing contact between immune cells and the surrounding target cells. Tumor cells protected from cytotoxicity by NETs underlie successful cancer metastases in mice and the immunotherapeutic synergy of protein arginine deiminase 4 (PAD4) inhibitors, which curtail NETosis with immune checkpoint inhibitors. Intravital microscopy provides evidence of neutrophil NETs interfering cytolytic cytotoxic T lymphocytes (CTLs) and NK cell contacts with tumor cells.ConclusionsCXCR1 and 2 are the main receptors mediating NETosis of tumor associated neutrophils in our in-vitro and in vivo systems expressing high levels of CXCR1 and 2 ligands. NETs limit cancer cell cytotoxicity by impeding contacts with cancer cells.

Are neutrophil extracellular traps the link for the cross-talk between periodontitis and rheumatoid arthritis physiopathology?

Rheumatology ◽  
2021 ◽  
Author(s):  
Sicília Rezende Oliveira ◽  
José Alcides A de Arruda ◽  
Ayda Henriques Schneider ◽  
Valessa Florindo Carvalho ◽  
Caio Machado ◽  
...  
Keyword(s):  
Rheumatoid Arthritis ◽  
Cross Talk ◽  
Neutrophil Extracellular Traps ◽  
Periodontal Therapy ◽  
Clinical Parameters ◽  
Extracellular Traps ◽  
Early Ra ◽  
The Cross ◽  
High Concentrations ◽  
The Impact

Abstract Objectives Neutrophil extracellular traps (NETs) play a role in the pathogenesis of periodontitis and rheumatoid arthritis (RA). However, it remains poorly understood whether NETs participate in the cross-talk between periodontitis and RA. Herein, we investigated the production of NETs in individuals with periodontitis and RA and its association with clinical parameters. The impact of periodontal therapy on RA and NET release was also assessed. Methods The concentration of NETs and cytokines was determined in the saliva and plasma of individuals with early RA (n = 24), established RA (n = 64), and individuals without RA (n = 76). The influence of periodontitis on the production of NETs and cytokines was also evaluated. Results Individuals with early RA had a higher concentration of NETs in saliva and plasma than individuals with established RA or without RA. Periodontitis resulted in an increase in the concentration of NETs of groups of individuals without RA and with early RA. The proportion of individuals with high concentrations of IL-6, IL-10 and GM-CSF was higher among individuals with periodontitis than among individuals without periodontitis. The concentrations of TNF-α, IL-6, IL-17/IL-25, and IL-28A were particularly high in individuals with early RA. Worse periodontal clinical parameters, RA onset and RA activity were significantly associated with circulating NETs. Periodontal therapy was associated with a reduction in the concentration of NETs and inflammatory cytokines and amelioration in periodontitis and RA. Conclusion This study reveals that NETs are a possible link between periodontitis and RA, with periodontal therapy resulting in a dramatic switch in circulating NET levels.

scholarly journals AB0048 ENZYMATIC PATTERN OF CIRCULATING PRO- AND ANTIOXIDANT ENZYMES IN RHEUMATOID ARTHRITIS PATIENTS

2021 ◽  
Vol 80 (Suppl 1) ◽  
pp. 1056.2-1057
Author(s):  
S. Bedina ◽  
E. Mozgovaya ◽  
A. Trofimenko ◽  
S. Spitsina ◽  
M. Mamus
Keyword(s):  
Rheumatoid Arthritis ◽  
Antioxidant Enzymes ◽  
Disease Activity ◽  
Neutrophil Extracellular Traps ◽  
Unknown Etiology ◽  
Antioxidant Enzyme Activities ◽  
Reference Ranges ◽  
Sod Activity ◽  
Low Disease Activity ◽  
Extracellular Traps

Background:Rheumatoid arthritis (RA) is an autoimmune rheumatic disease of unknown etiology characterized by chronic erosive arthritis and systemic organ involvement resulting in early disability and shorter life expectancy. Neutrophils are suggested to play a substantial role in the induction and promotion of autoimmune inflammation in RA. This ability can be based on newly discovered feature of neutrophils to release neutrophil extracellular traps (NETs) during specific type cell death called NETosis. Hyperproduction of reactive oxygen species (ROS) is one of the factors promoting NETs production. With this background, the study of pro- and antioxidant enzymatic activities in RA patients can be of great interest.Objectives:To assess plasma activities of essential prooxidant and antioxidant enzymes in RA patients.Methods:The research was carried out in agreement with the WMA Declaration of Helsinki principles. 71 RA patients (46 women and 25 men) were enrolled in the study. The diagnosis was verified using ACR/EULAR criteria (2010). RA activity was measured using the Disease Activity Score of 28 joints (DAS28). 30 healthy persons comprise control group. Plasma xanthine oxidase (XO; ЕС 1.17.3.2), xanthine dehydrogenase (XDH; ЕС 1.17.1.4) and superoxide dismutase (SOD; ЕС 1.15.1.1) activities were measured using spectrophotometric technique. XO and XDG activities were expressed as nmol/ml/min, SOD activity – as units of action. Statistical analysis was performed using Statistica 6.0 software package. Differences were considered significant when p<0.05. Reference ranges were calculated as means ±2SD.Results:Mean age of patients was 43.2±3.6 years, mean RA duration was 11.9±2.6 years. 24 (33.8%) RA patients had low disease activity, and 6 (8.5%) patients had high one. Extra-articular manifestations were found in 30 (42.2%) patients. 30% of them had cardiovascular involvement, 23.3% – pulmonary lesions, and 23.3% had renal involvement. Reference ranges for XO, XDG, and SOD activities were 2.28-5.12 nmol/min/ml, 3,96-7,24 nmol/min/ml, and 3,13-6,58 units, respectively. We examined activities of these enzymes in circulation of RA patients with different patterns of clinical manifestations as well as relationship between RA activity and XO, XDG, and SOD activities. RA patients had increased both mean XO and mean SOD activities (p<0.001 for both enzymes). XO activity reached its highest values at maximum disease activity and overt extra-articular involvements, while SOD activity did it in moderate and high disease activities as well as in patients with joint manifestations. XDG activity was increased in low disease activity (р<0.001) and solely joint lesions (р=0.011), while moderate or high disease activities (р=0.008) and extra-articular involvements (р=0.025) were characterized by decreased activity of this enzyme.Conclusion:We have revealed substantial multidirectional changes of plasma XO and XDG activities in RA. Plasma enzymatic pattern in RA patients is characterized by activation of both oxidant and antioxidant metabolic pathways. Activities of XO and SOD were positively correlated with RA activity, while XDG activity was negative correlated with RA activity. The differences between selective articular RA type and RA form with extraarticular manifestations were also revealed. Changes in oxidant and antioxidant enzyme activities can be connected with anticitrulline autoimmunity in RA via production of citrulline-rich neutrophil extracellular traps, thus enhancing rheumatoid autoimmunity.Disclosure of Interests:None declared

scholarly journals Neutrophil Extracellular Traps Serve as Key Effector Molecules in the Protection Against Phialophora verrucosa

2021 ◽  
Vol 186 (3) ◽  
pp. 367-375
Author(s):  
Qin Liu ◽  
Wenjuan Yi ◽  
Si Jiang ◽  
Jiquan Song ◽  
Pin Liang
Keyword(s):  
Neutrophil Extracellular Traps ◽  
Innate Immune ◽  
Immune Effector ◽  
Phialophora Verrucosa ◽  
Extracellular Traps ◽  
Sytox Green ◽  
Innate Immune Effector ◽  
Pathogen Control ◽  
Extracellular Structures

AbstractPhialophora verrucosa (P. verrucosa) is a pathogen that can cause chromoblastomycosis and phaeohyphomycosis. Recent evidence suggests that neutrophils can produce neutrophil extracellular traps (NETs) that can protect against invasive pathogens. As such, we herein explored the in vitro functional importance of P. verrucosa-induced NET formation. By assessing the co-localization of neutrophil elastase and DNA, we were able to confirm the formation of classical NETs entrapping P. verrucosa specimens. Sytox Green was then used to stain these NETs following neutrophil infection with P. verrucosa in order to quantify the formation of these extracellular structures. NET formation was induced upon neutrophil exposure to both live, UV-inactivated, and dead P. verrucosa fungi. The ability of these NETs to kill fungal hyphae and conidia was demonstrated through MTT and pouring plate assays, respectively. Overall, our results confirmed that P. verrucosa was able to trigger the production of NETs, suggesting that these extracellular structures may represent an important innate immune effector mechanism controlling physiological responses to P. verrucosa infection, thereby aiding in pathogen control during the acute phases of infection.

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