scholarly journals Silver Nanoparticles Induce Neutrophil Extracellular Traps Via Activation of PAD and Neutrophil Elastase

Biomolecules ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 317
Author(s):  
HanGoo Kang ◽  
Jinwon Seo ◽  
Eun-Jeong Yang ◽  
In-Hong Choi
Keyword(s):  
Silver Nanoparticles ◽  
Neutrophil Elastase ◽  
Mammalian Cells ◽  
Antimicrobial Properties ◽  
Neutrophil Extracellular Traps ◽  
Arginine Deiminase ◽  
Human Neutrophils ◽  
Extracellular Traps ◽  
Peptidyl Arginine Deiminase ◽  
Key Factor

Silver nanoparticles (AgNPs) are widely used in various fields because of their antimicrobial properties. However, many studies have reported that AgNPs can be harmful to both microorganisms and humans. Reactive oxygen species (ROS) are a key factor of cytotoxicity of AgNPs in mammalian cells and an important factor in the immune reaction of neutrophils. The immune reactions of neutrophils include the expulsion of webs of DNA surrounded by histones and granular proteins. These webs of DNA are termed neutrophil extracellular traps (NETs). NETs allow neutrophils to catch and destroy pathogens in extracellular spaces. In this study, we investigated how AgNPs stimulate neutrophils, specifically focusing on NETs. Freshly isolated human neutrophils were treated with 5 or 100 nm AgNPs. The 5 nm AgNPs induced NET formation, but the 100 nm AgNPs did not. Subsequently, we investigated the mechanism of AgNP-induced NETs using known inhibitors related to NET formation. AgNP-induced NETs were dependent on ROS, peptidyl arginine deiminase, and neutrophil elastase. The result in this study indicates that treatment of 5 nm AgNPs induce NET formation through histone citrullination by peptidyl arginine deiminase and histone cleavage by neutrophil elastase.

scholarly journals Neutrophil Extracellular Traps Promote the Development of Intracranial Aneurysm Rupture

Hypertension ◽  
2021 ◽  
Author(s):  
Masaaki Korai ◽  
James Purcell ◽  
Yoshinobu Kamio ◽  
Kazuha Mitsui ◽  
Hajime Furukawa ◽  
...  
Keyword(s):  
Intracranial Aneurysm ◽  
Interleukin 1 ◽  
Neutrophil Extracellular Traps ◽  
Aneurysm Rupture ◽  
Arginine Deiminase ◽  
Intercellular Adhesion Molecule ◽  
Necrosis Factor Alpha ◽  
Extracellular Traps ◽  
Peptidyl Arginine Deiminase ◽  
Aneurysm Wall

Potential roles for neutrophils in the pathophysiology of intracranial aneurysm have long been suggested by clinical observations. The presence of neutrophil enzymes in the aneurysm wall has been associated with significant increases in rupture risk. However, the mechanisms by which neutrophils may promote aneurysm rupture are not well understood. Neutrophil extracellular traps (NETs) were implicated in many diseases that involve inflammation and tissue remodeling, including atherosclerosis, vasculitis, and abdominal aortic aneurysm. Therefore, we hypothesized that NETs may promote the rupture of intracranial aneurysm, and that removal of NETs can reduce the rate of rupture. We employed both pharmacological and genetic approaches for the disruption of NETs and used a mouse model of intracranial aneurysm to investigate the roles of NETs in the development of intracranial aneurysm rupture. Here, we showed that NETs are detected in human intracranial aneurysms. Both global and granulocyte-specific knockout of peptidyl arginine deiminase 4 (an enzyme essential for NET formation) reduced the rate of aneurysm rupture. Pharmacological blockade of the NET formation by Cl-amidine also reduced the rate of aneurysm rupture. In addition, the resolution of already formed NETs by deoxyribonuclease was effective against aneurysm rupture. Inhibition of NETs formation with Cl-amidine decreased mRNA expression of proinflammatory cytokines (intercellular adhesion molecule 1 (ICAM-1), interleukin 1 beta (IL-1β), monocyte chemoattractant protein-1 (MCP-1), and tumor necrosis factor alpha (TNF-α)) in cerebral arteries. These data suggest that NETs promote the rupture of intracranial aneurysm. Pharmacological removal of NETs, by inhibition of peptidyl arginine deiminase 4 or resolution of already-formed NETs, may represent a potential therapeutic strategy for preventing aneurysmal rupture.

Neutrophil extracellular traps mediate joint hyperalgesia induced by immune inflammation

Rheumatology ◽  
2020 ◽  
Author(s):  
Ayda Henriques Schneider ◽  
Caio Cavalcante Machado ◽  
Flávio Protásio Veras ◽  
Alexandre Gomes de Macedo Maganin ◽  
Flávio Falcão Lima de Souza ◽  
...  
Keyword(s):  
Clinical Investigation ◽  
Neutrophil Extracellular Traps ◽  
Arginine Deiminase ◽  
Human Neutrophils ◽  
Oedema Formation ◽  
Extracellular Traps ◽  
Mechanical Threshold ◽  
Articular Pain ◽  
Dose Dependent

Abstract Objective To evaluate the role of neutrophil extracellular traps (NETs) in the genesis of joint hyperalgesia using an experimental model of arthritis and transpose the findings to clinical investigation. Methods C57BL/6 mice were subjected to antigen-induced arthritis (AIA) and treated with Pulmozyme (PLZ) to degrade NETs or Cl-amidine to inhibit NET production. Oedema formation, the histopathological score and mechanical hyperalgesia were evaluated. NETs were injected intra-articularly in wild type (WT), Tlr4−/−, Tlr9−/−, Tnfr1−/− and Il1r−/− mice, and the levels of cytokines and Cox2 expression were quantified. NETs were also quantified from human neutrophils isolated from RA patients and individual controls. Results AIA mice had increased NET concentration in joints, accompanied by increased Padi4 gene expression in the joint cells. Treatment of AIA mice with a peptidyl arginine deiminase 4 inhibitor or with PLZ inhibited the joint hyperalgesia. Moreover, the injection of NETs into joints of naïve animals generated a dose-dependent reduction of mechanical threshold, an increase of articular oedema, inflammatory cytokine production and cyclooxygenase-2 expression. In mice deficient for Tnfr1, Il1r, Tlr4 and Tlr9, joint hyperalgesia induced by NETs was prevented. Last, we found that neutrophils from RA patients were more likely to release NETs, and the increase in synovial fluid NET concentration correlated with an increase in joint pain. Conclusion The findings indicate that NETs cause hyperalgesia possibly through Toll-like receptor (TLR)-4 and TLR-9. These data support the idea that NETs contribute to articular pain, and this pathway can be an alternative target for the treatment of pain in RA.

scholarly journals Filifactor alocis manipulates human neutrophils affecting their ability to release neutrophil extracellular traps induced by PMA

2018 ◽  
Vol 24 (4) ◽  
pp. 210-220 ◽  
Author(s):  
Cortney L Armstrong ◽  
Christopher K Klaes ◽  
Aruna Vashishta ◽  
Richard J Lamont ◽  
Silvia M Uriarte
Keyword(s):  
Neutrophil Elastase ◽  
Neutrophil Extracellular Traps ◽  
Periodontal Pathogen ◽  
Periodontal Pocket ◽  
Human Neutrophils ◽  
Streptococcus Gordonii ◽  
Periodontal Health ◽  
Extracellular Traps ◽  
Tnf Α ◽  
Filifactor Alocis

Neutrophils operate at the site of injury or inflammation in the periodontal pocket to ensure periodontal health and clearance of bacterial pathogens. Filifactor alocis is recently identified as a potential periodontal pathogen, and in this study, we assessed the formation of neutrophil extracellular traps (NETs), in response to the presence of the organism . NET formation by human neutrophils was not induced when challenged with F. alocis, independent of opsonization, viability, time, or bacterial dose. F. alocis also failed to induce NETs from TNF-α-primed neutrophils and did not induce the release of extracellular neutrophil elastase. However, significant NET induction was observed when neutrophils were challenged with Streptococcus gordonii or Peptoanaerobacter stomatis, In addition, co-infection studies revealed that the presence of F. alocis with S. gordonii or P. stomatis does not enhance or reduce NETs. Additionally, F. alocis failed to impact pre-formed NETs induced by either S. gordonii or P. stomatis. Pretreatment with F. alocis prior to stimulation with phorbol 12-myristate 13-acetate (PMA), S. gordonii, or P. stomatis revealed that the bacterium is capable of reducing only PMA but not S. gordonii or P. stomatis NET formation. These results indicate that F. alocis manipulates neutrophils, inhibiting the triggering of NET induction.

scholarly journals Neutrophil elastase and myeloperoxidase regulate the formation of neutrophil extracellular traps

2010 ◽  
Vol 191 (3) ◽  
pp. 677-691 ◽  
Author(s):  
Venizelos Papayannopoulos ◽  
Kathleen D. Metzler ◽  
Abdul Hakkim ◽  
Arturo Zychlinsky
Keyword(s):  
Immune Deficiency ◽  
Neutrophil Elastase ◽  
Serine Proteases ◽  
Neutrophil Extracellular Traps ◽  
Oxygen Species ◽  
Chromatin Decondensation ◽  
Unknown Mechanism ◽  
Extracellular Traps ◽  
Decondensed Chromatin ◽  
Chromatin Density

Neutrophils release decondensed chromatin termed neutrophil extracellular traps (NETs) to trap and kill pathogens extracellularly. Reactive oxygen species are required to initiate NET formation but the downstream molecular mechanism is unknown. We show that upon activation, neutrophil elastase (NE) escapes from azurophilic granules and translocates to the nucleus, where it partially degrades specific histones, promoting chromatin decondensation. Subsequently, myeloperoxidase synergizes with NE in driving chromatin decondensation independent of its enzymatic activity. Accordingly, NE knockout mice do not form NETs in a pulmonary model of Klebsiella pneumoniae infection, which suggests that this defect may contribute to the immune deficiency of these mice. This mechanism provides for a novel function for serine proteases and highly charged granular proteins in the regulation of chromatin density, and reveals that the oxidative burst induces a selective release of granular proteins into the cytoplasm through an unknown mechanism.

scholarly journals Capsular polysaccharides from Cryptococcus neoformans modulate production of neutrophil extracellular traps (NETs) by human neutrophils

2015 ◽  
Vol 5 (1) ◽  
Author(s):  
Juliana D. B. Rocha ◽  
Michelle T. C. Nascimento ◽  
Debora Decote-Ricardo ◽  
Suzana Côrte-Real ◽  
Alexandre Morrot ◽  
...  
Keyword(s):  
Cryptococcus Neoformans ◽  
Neutrophil Extracellular Traps ◽  
Human Neutrophils ◽  
Capsular Polysaccharides ◽  
Extracellular Traps

Exosomal MALAT1 derived from ox-LDL-treated endothelial cells induce neutrophil extracellular traps to aggravate atherosclerosis

2020 ◽  
Vol 401 (3) ◽  
pp. 367-376 ◽  
Author(s):  
Hailai Gao ◽  
XiaoLi Wang ◽  
Chaolan Lin ◽  
Zhujun An ◽  
Jiangbo Yu ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Umbilical Vein ◽  
Low Density Lipoprotein ◽  
Atherosclerotic Lesion ◽  
Density Lipoprotein ◽  
Neutrophil Extracellular Traps ◽  
Human Neutrophils ◽  
Enzyme Linked Immunosorbent Assay ◽  
Extracellular Traps ◽  
Umbilical Vein Endothelial Cells

AbstractThe objective of this study was to reveal a novel mechanism underlying the progression of atherosclerosis (AS) associated with endothelial cells (ECs) and neutrophils. Transmission electron microscopy (TEM) and nanoparticle tracking analysis (NTA) were used to observe the morphology and particle size of isolated exosomes. Western blotting was applied to examine exosomal markers, while the expression of metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) was measured by quantitative real-time polymerase chain reaction (qRT-PCR). The production of inflammatory cytokines and reactive oxygen species (ROS) was determined by an enzyme-linked immunosorbent assay (ELISA) and a dichloro-dihydro-fluorescein diacetate (DCFH-DA) assay. Circulating neutrophil extracellular traps (NETs) were represented by myeloperoxidase (MPO)-DNA complexes. NETs formation was assessed using immunofluorescence microscopy. Atherosclerotic lesion development was measured by Oil Red O (ORO) staining. In the results, MALAT1 expression was increased in exosomes extracted from oxidized low-density lipoprotein (ox-LDL)-treated human umbilical vein endothelial cells (HUVECs). When co-cultured with human neutrophils, exosomes derived from ox-LDL-treated HUVECs were revealed to promote NETs formation, which was mediated by exosomal MALAT1. Furthermore, ox-LDL-treated HUVECs-derived exosomes were demonstrated to trigger hyperlipidemia, inflammatory response and NETs release in a mouse model of AS. In conclusion, exosomal MALAT1 derived from ox-LDL-treated ECs initiated NETs formation, which in turn deteriorated AS.

scholarly journals Nitric oxide and peroxynitrite trigger and enhance release of neutrophil extracellular traps

2019 ◽  
Vol 77 (15) ◽  
pp. 3059-3075 ◽  
Author(s):  
Aneta Manda-Handzlik ◽  
Weronika Bystrzycka ◽  
Adrianna Cieloch ◽  
Eliza Glodkowska-Mrowka ◽  
Ewa Jankowska-Steifer ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Nitrosative Stress ◽  
Calcium Ionophore ◽  
Neutrophil Extracellular Traps ◽  
Calcium Ionophore A23187 ◽  
Human Neutrophils ◽  
Ionophore A23187 ◽  
Inflammatory Reactions ◽  
Extracellular Traps

Abstract Despite great interest, the mechanism of neutrophil extracellular traps (NETs) release is not fully understood and some aspects of this process, e.g. the role of reactive nitrogen species (RNS), still remain unclear. Therefore, our aim was to investigate the mechanisms underlying RNS-induced formation of NETs and contribution of RNS to NETs release triggered by various physiological and synthetic stimuli. The involvement of RNS in NETs formation was studied in primary human neutrophils and differentiated human promyelocytic leukemia cells (HL-60 cells). RNS (peroxynitrite and nitric oxide) efficiently induced NETs release and potentiated NETs-inducing properties of platelet activating factor and lipopolysaccharide. RNS-induced NETs formation was independent of autophagy and histone citrullination, but dependent on the activity of phosphoinositide 3-kinases (PI3K) and myeloperoxidase, as well as selective degradation of histones H2A and H2B by neutrophil elastase. Additionally, NADPH oxidase activity was required to release NETs upon stimulation with NO, as shown in NADPH-deficient neutrophils isolated from patients with chronic granulomatous disease. The role of RNS was further supported by increased RNS synthesis upon stimulation of NETs release with phorbol 12-myristate 13-acetate and calcium ionophore A23187. Scavenging or inhibition of RNS formation diminished NETs release triggered by these stimuli while scavenging of peroxynitrite inhibited NO-induced NETs formation. Our data suggest that RNS may act as mediators and inducers of NETs release. These processes are PI3K-dependent and ROS-dependent. Since inflammatory reactions are often accompanied by nitrosative stress and NETs formation, our studies shed a new light on possible mechanisms engaged in various immune-mediated conditions.

Neutrophil Extracellular Traps Induce Platelet Adhesion and Thrombus Formation.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 1345-1345 ◽  
Author(s):  
Tobias Fuchs ◽  
Alexander Brill ◽  
Daniel Dürschmied ◽  
Daphne Schatzberg ◽  
John H. Hartwig ◽  
...  
Keyword(s):  
Whole Blood ◽  
Platelet Adhesion ◽  
Conflicts Of Interest ◽  
Thrombus Formation ◽  
Neutrophil Extracellular Traps ◽  
Thrombin Inhibitor ◽  
Human Neutrophils ◽  
Dependent Manner ◽  
Extracellular Traps ◽  
Deep Vein

Abstract Abstract 1345 Introduction Thrombus stability is provided by very large polymers adhering to platelets and anchoring the thrombus to the vessel wall. The best described polymers are fibrin and von Willebrand Factor (VWF). Activated neutrophils and other leukocytes can form an extracellular fibrous network which is composed of DNA, histones, and granular proteins. These neutrophil extracellular traps (NETs) are present in various inflammatory diseases. In deep vein thrombosis (DVT) inflammation closely cooperates with thrombosis. Here we examine whether NETs provide a new means to support the adhesion and recruitment of platelets and whether NETs are present in DVT. Methods and Results: To study the interaction of platelets with NETs, we isolated human neutrophils, induced NET formation and perfused over the NETs human platelets in plasma or whole blood anticoagulated with the thrombin inhibitor PPACK. Microscopic analysis revealed that under flow platelets adhere avidly to NETs. Perfusion of whole blood at physiological shear resulted in formation of thrombi on NETs in a time dependent manner. Addition of DNase1 degraded NETs and removed all platelets and thrombi demonstrating their adhesion to NETs. Thrombus formation on NETs was absent if blood was supplemented with EDTA indicating the requirement for divalent cations. Perfusion of NETs with heparinized blood dismantled NETs and prevented thrombus formation. Incubation of NETs with heparin alone released histones from NETs, indicating that heparin destroys the chromatin backbone of NETs. Furthermore, immunocytochemistry revealed that NETs were able to bind platelet adhesion molecules VWF and fibronectin from human plasma. Immunohistochemical analysis of a baboon deep vein thrombus showed abundant extracellular chromatin which co-localized with fibronectin and VWF. Conclusions: We show that extracellular traps are able to promote thrombosis in vitro and are abundant in vivo in DVT. We propose that extracellular chromatin provides a new type of scaffold that promotes platelet adhesion, activation, and aggregation and may be important for thrombus initiation or stability. Disclosures No relevant conflicts of interest to declare.

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