scholarly journals Neutrophil Extracellular Traps (NETs) in Severe SARS-CoV-2 Lung Disease

2021 ◽  
Vol 22 (16) ◽  
pp. 8854
Author(s):  
Monika Szturmowicz ◽  
Urszula Demkow

Neutrophil extracellular traps (NETs), built from mitochondrial or nuclear DNA, proteinases, and histones, entrap and eliminate pathogens in the course of bacterial or viral infections. Neutrophils’ activation and the formation of NETs have been described as major risk factors for acute lung injury, multi-organ damage, and mortality in COVID-19 disease. NETs-related lung injury involves both epithelial and endothelial cells, as well as the alveolar-capillary barrier. The markers for NETs formation, such as circulating DNA, neutrophil elastase (NE) activity, or myeloperoxidase-DNA complexes, were found in lung specimens of COVID-19 victims, as well as in sera and tracheal aspirates obtained from COVID-19 patients. DNA threads form large conglomerates causing local obstruction of the small bronchi and together with NE are responsible for overproduction of mucin by epithelial cells. Various components of NETs are involved in the pathogenesis of cytokine storm in SARS-CoV-2 pulmonary disease. NETs are responsible for the interplay between inflammation and thrombosis in the affected lungs. The immunothrombosis, stimulated by NETs, has a poor prognostic significance. Better understanding of the role of NETs in the course of COVID-19 can help to develop novel approaches to the therapeutic interventions in this condition.

2014 ◽  
Vol 307 (7) ◽  
pp. L586-L596 ◽  
Author(s):  
Lingtao Luo ◽  
Su Zhang ◽  
Yongzhi Wang ◽  
Milladur Rahman ◽  
Ingvar Syk ◽  
...  

Excessive neutrophil activation is a major component in septic lung injury. Neutrophil-derived DNA may form extracellular traps in response to bacterial invasions. The aim of the present study was to investigate the potential role of neutrophil extracellular traps (NETs) in septic lung injury. Male C57BL/6 mice were treated with recombinant human (rh)DNAse (5 mg/kg) after cecal ligation and puncture (CLP). Extracellular DNA was stained by Sytox green, and NET formation was quantified by confocal microscopy and cell-free DNA in plasma, peritoneal cavity, and lung. Blood, peritoneal fluid, and lung tissue were harvested for analysis of neutrophil infiltration, NET levels, tissue injury, as well as CXC chemokine and cytokine formation. We observed that CLP caused increased formation of NETs in plasma, peritoneal cavity, and lung. Administration of rhDNAse not only eliminated NET formation in plasma, peritoneal cavity, and bronchoalveolar space but also reduced lung edema and tissue damage 24 h after CLP induction. Moreover, treatment with rhDNAse decreased CLP-induced formation of CXC chemokines, IL-6, and high-mobility group box 1 (HMGB1) in plasma, as well as CXC chemokines and IL-6 in the lung. In vitro, we found that neutrophil-derived NETs had the capacity to stimulate secretion of CXCL2, TNF-α, and HMGB1 from alveolar macrophages. Taken together, our findings show that NETs regulate pulmonary infiltration of neutrophils and tissue injury via formation of proinflammatory compounds in abdominal sepsis. Thus we conclude that NETs exert a proinflammatory role in septic lung injury.


2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Elcha Charles ◽  
Benjamin L. Dumont ◽  
Steven Bonneau ◽  
Paul-Eduard Neagoe ◽  
Louis Villeneuve ◽  
...  

Abstract Background Neutrophils induce the synthesis and release of angiopoietin 1 (Ang1), a cytosolic growth factor involved in angiogenesis and capable of inducing several pro-inflammatory activities in neutrophils. Neutrophils also synthesize and release neutrophil extracellular traps (NETs), comprised from decondensed nuclear DNA filaments carrying proteins such as neutrophil elastase (NE), myeloperoxidase (MPO), proteinase 3 (PR3) and calprotectin (S100A8/S100A9), which together, contribute to the innate immune response against pathogens (e.g., bacteria). NETs are involved in various pathological conditions through pro-inflammatory, pro-thrombotic and endothelial dysfunction effects and have recently been found in heart failure (HF) and type 2 diabetes (T2DM) patients. The aim of the present study was to investigate the role of NETs on the synthesis and release of Ang1 by the neutrophils in patients with T2DM and HF with preserved ejection fraction (HFpEF) (stable or acute decompensated; ADHFpEF) with or without T2DM. Results Our data show that at basal level (PBS) and upon treatment with LPS, levels of NETs are slightly increased in patients suffering from T2DM, HFpEF ± T2DM and ADHF without (w/o) T2DM, whereas this increase was significant in ADHFpEF + T2DM patients compared to healthy control (HC) volunteers and ADHFpEF w/o T2DM. We also observed that treatments with PMA or A23187 increase the synthesis of Ang1 (from 150 to 250%) in HC and this effect is amplified in T2DM and in all cohorts of HF patients. Ang1 is completely released (100%) by neutrophils of all groups and does not bind to NETs as opposed to calprotectin. Conclusions Our study suggests that severely ill patients with HFpEF and diabetes synthesize and release a greater abundance of NETs while Ang1 exocytosis is independent of NETs synthesis.


JCI Insight ◽  
2018 ◽  
Vol 3 (3) ◽  
Author(s):  
Emma Lefrançais ◽  
Beñat Mallavia ◽  
Hanjing Zhuo ◽  
Carolyn S. Calfee ◽  
Mark R. Looney

2020 ◽  
Vol 58 (5) ◽  
pp. 419-420 ◽  
Author(s):  
Ahmed Yaqinuddin ◽  
Peter Kvietys ◽  
Junaid Kashir

2021 ◽  
Author(s):  
Elcha Charles ◽  
Benjamin Dumont ◽  
Steven Bonneau ◽  
Paul-Eduard Neagoe ◽  
Louis Villeneuve ◽  
...  

Abstract Background: Neutrophils induce the synthesis and release of angiopoietin 1 (Ang1), a cytosolic growth factor involved in angiogenesis and capable of inducing several pro-inflammatory activities in neutrophils. Neutrophils also synthesize and release neutrophil extracellular traps (NETs), comprised from decondensed nuclear DNA filaments carrying proteins such as neutrophil elastase (NE), myeloperoxidase (MPO), proteinase 3 (PR3) and calprotectin (S100A8/S100A9), which together, contribute to the innate immune response against pathogens (e.g., bacteria). NETs are involved in various pathological conditions through pro-inflammatory, pro-thrombotic and endothelial dysfunction effects and have recently been found in heart failure (HF) and type 2 diabetes (T2DM) patients. The aim of the present study was to investigate the role of NETs on the synthesis and release of Ang1 by the neutrophils in patients with T2DM and HF with preserved ejection fraction (HFpEF) (stable or acute decompensated; ADHFpEF) with or without T2DM. Results: Our data show that at basal level (PBS) and upon treatment with LPS, levels of NETs are slightly increased in patients suffering from T2DM, HFpEF ± T2DM and ADHF w/o T2DM, whereas this increase was significant in ADHFpEF + T2DM patients compared to healthy control (HC) volunteers and ADHFpEF without T2DM. We also observed that treatments with PMA or A23187 increase the synthesis of Ang1 (from 150 to 250%) in HC and this effect is amplified in T2DM and in all cohorts of HF patients. Ang1 is completely released (100%) by neutrophils of all groups and does not bind to NETs as opposed to calprotectin. Conclusions: Our study suggests that severely ill patients with HFpEF and diabetes synthesize and release a greater abundance of NETs while Ang1 exocytosis is independent of NETs synthesis.


Acta Naturae ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 15-23
Author(s):  
Dmitry V. Volkov ◽  
George V. Tetz ◽  
Yury P. Rubtsov ◽  
Alexey V. Stepanov ◽  
Alexander G. Gabibov

Antitumor therapy, including adoptive immunotherapy, inevitably faces powerful counteraction from advanced cancer. If hematological malignancies are currently amenable to therapy with CAR-T lymphocytes (T-cells modified by the chimeric antigen receptor), solid tumors, unfortunately, show a significantly higher degree of resistance to this type of therapy. As recent studies show, the leading role in the escape of solid tumors from the cytotoxic activity of immune cells belongs to the tumor microenvironment (TME). TME consists of several types of cells, including neutrophils, the most numerous cells of the immune system. Recent studies show that the development of the tumor and its ability to metastasize directly affect the extracellular traps of neutrophils (neutrophil extracellular traps, NETs) formed as a result of the response to tumor stimuli. In addition, the nuclear DNA of neutrophils the main component of NETs erects a spatial barrier to the interaction of CAR-T with tumor cells. Previous studies have demonstrated the promising potential of deoxyribonuclease I (DNase I) in the destruction of NETs. In this regard, the use of eukaryotic deoxyribonuclease I (DNase I) is promising in the effort to increase the efficiency of CAR-T by reducing the NETs influence in TME. We will examine the role of NETs in TME and the various approaches in the effort to reduce the effect of NETs on a tumor.


Cells ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1689
Author(s):  
Manovriti Thakur ◽  
Bryce Evans ◽  
Marc Schindewolf ◽  
Iris Baumgartner ◽  
Yvonne Döring

Neutrophil extracellular traps (NETs) are web-like structures of decondensed extracellular chromatin fibers and neutrophil granule proteins released by neutrophils. NETs participate in host immune defense by entrapping pathogens. They are pro-inflammatory in function, and they act as an initiator of vascular coagulopathies by providing a platform for the attachment of various coagulatory proteins. NETs are diverse in their ability to alter physiological and pathological processes including infection and inflammation. In this review, we will summarize recent findings on the role of NETs in bacterial/viral infections associated with vascular inflammation, thrombosis, atherosclerosis and autoimmune disorders. Understanding the complex role of NETs in bridging infection and chronic inflammation as well as discussing important questions related to their contribution to pathologies outlined above may pave the way for future research on therapeutic targeting of NETs applicable to specific infections and inflammatory disorders.


Author(s):  
Hao Zhang ◽  
Yilu Zhou ◽  
Mengdi Qu ◽  
Ying Yu ◽  
Zhaoyuan Chen ◽  
...  

BackgroundPatients with sepsis may progress to acute respiratory distress syndrome (ARDS). Evidence of neutrophil extracellular traps (NETs) in sepsis-induced lung injury has been reported. However, the role of circulating NETs in the progression and thrombotic tendency of sepsis-induced lung injury remains elusive. The aim of this study was to investigate the role of tissue factor-enriched NETs in the progression and immunothrombosis of sepsis-induced lung injury.MethodsHuman blood samples and an animal model of sepsis-induced lung injury were used to detect and evaluate NET formation in ARDS patients. Immunofluorescence imaging, ELISA, Western blotting, and qPCR were performed to evaluate in vitro NET formation and tissue factor (TF) delivery ability. DNase, an anti-TF antibody, and thrombin inhibitors were applied to evaluate the contribution of thrombin to TF-enriched NET formation and the contribution of TF-enriched NETs to immunothrombosis in ARDS patients.ResultsSignificantly increased levels of TF-enriched NETs were observed in ARDS patients and mice. Blockade of NETs in ARDS mice alleviated disease progression, indicating a reduced lung wet/dry ratio and PaO2 level. In vitro data demonstrated that thrombin-activated platelets were responsible for increased NET formation and related TF exposure and subsequent immunothrombosis in ARDS patients.ConclusionThe interaction of thrombin-activated platelets with PMNs in ARDS patients results in local NET formation and delivery of active TF. The notion that NETs represent a mechanism by which PMNs release thrombogenic signals during thrombosis may offer novel therapeutic targets.


Sign in / Sign up

Export Citation Format

Share Document