scholarly journals Neutrophil extracellular traps orchestrate formation of peritoneal adhesions

2021 ◽  
Author(s):  
Michael Boettcher ◽  
Lavinia Schönfeld ◽  
Annika Heuer ◽  
Julia Elrod ◽  
Carolin Stiel ◽  
...  
Keyword(s):  
Intestinal Obstruction ◽  
Essential Role ◽  
Adhesion Formation ◽  
Neutrophil Extracellular Traps ◽  
Experimental Models ◽  
Extracellular Dna ◽  
Murine Models ◽  
Therapeutic Application ◽  
Peritoneal Adhesions ◽  
Extracellular Traps

Abstract Peritoneal adhesions are a poorly understood but highly prevalent condition that can lead to intestinal obstruction, pelvic pain, and infertility. While there is consensus that stress-induced inflammation triggers peritoneal adhesions, the process of their formation remained elusive to date. Herein, we show that neutrophil extracellular traps (NETs) serve as essential scaffold for adhesion formation and that DNases interfere with this process. Thus, peritoneal adhesions in murine models and in humans showed that these lesions are largely based on extracellular DNA derived from neutrophils. Furthermore, treatment with DNASE1 or a DNASE1L3 analog significantly reduced or even prevented peritoneal adhesions in experimental models. These data not only suggest that NET formation plays an essential role in peritoneal adhesions but also show that therapeutic application of DNases can prevent the formation of peritoneal adhesions.

scholarly journals Detailed histological analysis of a thrombectomy-resistant ischemic stroke thrombus: a case report

2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Senna Staessens ◽  
Olivier François ◽  
Linda Desender ◽  
Peter Vanacker ◽  
Tom Dewaele ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Von Willebrand Factor ◽  
Histological Analysis ◽  
Mechanical Thrombectomy ◽  
Neutrophil Extracellular Traps ◽  
Extracellular Dna ◽  
Extracellular Traps ◽  
First Pass ◽  
Von Willebrand ◽  
Willebrand Factor

Abstract Background Mechanical removal of a thrombus by thrombectomy can be quite challenging. For reasons that are not fully understood, some thrombi require multiple passes to achieve successful recanalization, whereas other thrombi are efficiently removed in a single pass. Since first pass success is associated with better clinical outcome, it is important to better understand the nature of thrombectomy resistant thrombi. The aim of this study was therefore to characterize the cellular and molecular composition of a thrombus that was very hard to retrieve via mechanical thrombectomy. Case presentation In a patient that was admitted with a right middle cerebral artery M1-occlusion, 11 attempts using various thrombectomy devices and techniques were required for removal of the thrombus. This peculiar case provided a rare opportunity to perform an in-depth histopathological study of a difficult to retrieve thrombus. Thrombus material was histologically analyzed using hematoxylin and eosin, Martius Scarlet Blue stain (red blood cells and fibrin), Feulgen stain (DNA), von Kossa stain (calcifications) and immunohistochemical analysis of von Willebrand factor, platelets, leukocytes and neutrophil extracellular traps. Histological analysis revealed abnormally high amounts of extracellular DNA, leukocytes, von Willebrand factor and calcifications. Extracellular DNA stained positive for markers of leukocytes and NETs, suggesting that a significant portion of DNA is derived from neutrophil extracellular traps. Conclusion In this unique case of a nearly thrombectomy-resistant stroke thrombus, our study showed an atypical composition compared to the common structural features found in ischemic stroke thrombi. The core of the retrieved thrombus consisted of extracellular DNA that colocalized with von Willebrand factor and microcalcifications. These results support the hypothesis that von Willebrand factor, neutrophil extracellular traps and microcalcifications contribute to mechanical thrombectomy resistance. Such information is important to identify novel targets in order to optimize technical treatment protocols and techniques to increase first pass success rates.

scholarly journals Neutrophil Extracellular Traps Promote the Development and Growth of Human Salivary Stones

Cells ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 2139
Author(s):  
Mirco Schapher ◽  
Michael Koch ◽  
Daniela Weidner ◽  
Michael Scholz ◽  
Stefan Wirtz ◽  
...  
Keyword(s):  
Salivary Gland ◽  
Salivary Glands ◽  
Clinical Symptoms ◽  
Neutrophil Extracellular Traps ◽  
Physicochemical Process ◽  
Extracellular Dna ◽  
Neutrophil Granulocyte ◽  
Extracellular Traps ◽  
Efferent Ducts ◽  
Small Crystals

Salivary gland stones, or sialoliths, are the most common cause of the obstruction of salivary glands. The mechanism behind the formation of sialoliths has been elusive. Symptomatic sialolithiasis has a prevalence of 0.45% in the general population, is characterized by recurrent painful periprandial swelling of the affected gland, and often results in sialadenitis with the need for surgical intervention. Here, we show by the use of immunohistochemistry, immunofluorescence, computed tomography (CT) scans and reconstructions, special dye techniques, bacterial genotyping, and enzyme activity analyses that neutrophil extracellular traps (NETs) initiate the formation and growth of sialoliths in humans. The deposition of neutrophil granulocyte extracellular DNA around small crystals results in the dense aggregation of the latter, and the subsequent mineralization creates alternating layers of dense mineral, which are predominantly calcium salt deposits and DNA. The further agglomeration and appositional growth of these structures promotes the development of macroscopic sialoliths that finally occlude the efferent ducts of the salivary glands, causing clinical symptoms and salivary gland dysfunction. These findings provide an entirely novel insight into the mechanism of sialolithogenesis, in which an immune system-mediated response essentially participates in the physicochemical process of concrement formation and growth.

The screening of albumin as a key serum component to prevent neutrophil extracellular traps release by selectively inhibiting mitochondrial ROS generation

2020 ◽  
Author(s):  
Yue Zheng ◽  
Yuanfeng Zhu ◽  
Xin Liu ◽  
Hang Zheng ◽  
Yongjun Yang ◽  
...  
Keyword(s):  
Neutrophil Extracellular Traps ◽  
Extracellular Dna ◽  
Organ Injury ◽  
Ros Generation ◽  
Ros Production ◽  
Serum Free ◽  
Extracellular Traps ◽  
Mitochondrial Ros ◽  
Serum Component ◽  
Microbial Defense

Neutrophil extracellular traps (NETs) are extracellular DNA webs released from neutrophils to mediate host anti-microbial defense. As NETs could also induce thrombosis and cause organ injury, their release should be strictly controlled. However, it is not well understood about the intrinsic mechanisms that prevent unfavorable NETs. Herein, an accidental finding of NETs release from human peripheral neutrophils was firstly described in serum free culture, and it was also determined as a conserved effect for serum to prevent NETs. In contrast to canonical NETs induced by phorbol-12-myristate-13-acetate (PMA), NETs formation by serum free culture was rapid and without prevalent NETosis. Next, albumin was screened out as a key serum component that mediated the suppression of NETs. Moreover, NETs induced upon serum or albumin deficiency were independent of the canonical pathway that involves NOX2 activation and cytosol ROS production. Instead, the generation of mitochondrial ROS (mtROS) was upregulated to promote NETs release. Albumin exhibited mtROS scavenging activity and thus inhibited NETs. Serum free culture also induces the release of NET-bound oxidized mtDNA which stimulated IFN-β production. Overall, our research provides new evidences that characterize the NETs production in serum free culture and determine the mechanisms of serum albumin to inhibit NETs.

Proinflammatory role of neutrophil extracellular traps in abdominal sepsis

2014 ◽  
Vol 307 (7) ◽  
pp. L586-L596 ◽  
Author(s):  
Lingtao Luo ◽  
Su Zhang ◽  
Yongzhi Wang ◽  
Milladur Rahman ◽  
Ingvar Syk ◽  
...  
Keyword(s):  
Lung Injury ◽  
Peritoneal Cavity ◽  
Tissue Injury ◽  
Cecal Ligation ◽  
Neutrophil Extracellular Traps ◽  
Abdominal Sepsis ◽  
Extracellular Dna ◽  
Extracellular Traps ◽  
Proinflammatory Role

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.

scholarly journals Tissue Accumulation of Neutrophil Extracellular Traps Mediates Muscle Hyperalgesia in a Mouse Model

2021 ◽  
Author(s):  
Kazuaki Suzuki ◽  
Masahiro Tsuchiya ◽  
Shinichiro Yoshida ◽  
Kazumi Ogawa ◽  
Weijian Chen ◽  
...  
Keyword(s):  
Uric Acid ◽  
Muscle Contraction ◽  
Dna Cleavage ◽  
Neutrophil Extracellular Traps ◽  
Neutrophil Recruitment ◽  
Triceps Surae ◽  
Extracellular Dna ◽  
Xanthine Oxidase Inhibitor ◽  
Extracellular Traps ◽  
Neutrophil Depletion

Abstract Background: Accumulation of uric acid during muscular trauma is potentially a causative factor of damage-associated molecular patterns (DAMPs) involved in the development of muscle hyperalgesia. Neutrophil extracellular traps (NETs), DNA-based reticular structures to capture DAMPs, play a central role in the onset of pain in gout attacks associated with hyperuricemia; however, their association with muscle hyperalgesia due to overuse injuries remains unknown. Therefore, the aim of this study was to investigate the involvement of NETs via the elevation of local uric acid level in muscle nociception.Methods: The triceps surae muscles (TSMs) in the unilateral hindlimb of mice were repeatedly stimulated with electrical pulses to induce excessive muscle contraction, and the contralateral TSM was used as a control. In addition to mechanical nociceptive thresholds, tissue uric acid levels, neutrophil recruitment, protein amount, and histological distribution of citrullinated histone 3 (citH3), a major marker of NETs, were investigated. Furthermore, whether neutrophil depletion, extracellular DNA cleavage (deoxyribonuclease I), and administration of the urate-lowering agent febuxostat, a xanthine oxidase inhibitor, improved muscle hyperalgesia due to NET accumulation was examined. Using a combination of multiphoton imaging analysis and intravital fluorescence staining, we also evaluated the intramuscular distribution of NET accumulation in stimulated TSMs.Results: CitH3 expression upon neutrophil recruitment significantly increased in the stimulated TSMs tissues with an increase in tissue uric acid levels. However, neutrophil depletion and extracellular DNA cleavage prevented the increase in uric acid levels in damaged muscle tissues. Furthermore, febuxostat administration significantly improved muscle hyperalgesia, with decreases not only in citH3 and tissue uric acid levels, but also in neutrophil recruitment. Interestingly, the intramuscular distribution of NETs in the stimulated TSM was predominantly observed in the myofascial region.Conclusions: Our findings suggest that NET accumulation caused by excessive muscle contraction was strongly associated with the pathogenesis of muscle hyperalgesia. Further, the mechanism underlying induction of locally recruited neutrophils forming NETs was increased tissue uric acid levels, which potentially plays a significant role in creating a vicious circle of muscle pain.

scholarly journals Netome: The Molecular Characterization of Neutrophil Extracellular Traps (NETs)

2020 ◽  
Author(s):  
David Scieszka ◽  
Yi-Han Lin ◽  
Weizhong Li ◽  
Saibyasachi Choudhury ◽  
Yanbao Yu ◽  
...  
Keyword(s):  
Antimicrobial Agents ◽  
Genomic Sequence ◽  
White Blood Cells ◽  
Neutrophil Extracellular Traps ◽  
Extracellular Dna ◽  
Sterile Inflammation ◽  
Extracellular Milieu ◽  
Extracellular Traps ◽  
Genomics And Proteomics

AbstractNeutrophils are the most abundant type of white blood cells in humans with biological roles relevant to inflammation and fighting infections. The release of neutrophil extracellular DNA aims to control invasion by bacteria, viruses, fungi, and tissue damage. Neutrophil Extracellular Traps (NETs) act as antimicrobial agents triggering immune signaling through the release of the nuclear content into the extracellular space. Although intense investigations have elucidated the pathways preceding NET formation, the exact molecular composition of released NETs has not been mapped. We aimed to decode the sequences of DNA and proteins from NETs. With emerging needs to understand neutrophil functions precisely, we open the field of NETOMIC studies through isolation of NETs in combination with omics approaches including shotgun genomics and proteomics. Our in vitro NET isolation methodology allowed for unprecedented replicability with induction in a sterile inflammation model system. Enrichment of mitochondrial DNA and telomere sequences are significantly expressed in NET genomes. This study revealed that the genomic sequence released in the extracellular milieu is not stochastically serving as a scaffold for a repertoire of proteins involved in neutrophil protective functions. Collectively, we established the gene and protein signatures exclusive to the extracellular NETs in comparison to undifferentiated and differentiated neutrophil states, further guiding future detection of specific regions needed for diagnostics and targeted therapies of NET related conditions.

scholarly journals SOCE-inhibitor reduced human sperm-induced formation of neutrophil extracellular traps

Reproduction ◽  
2021 ◽  
Vol 161 (1) ◽  
pp. 21-29
Author(s):  
Fabiola Zambrano ◽  
Liliana Silva ◽  
Pamela Uribe ◽  
Ulrich Gärtner ◽  
Anja Taubert ◽  
...  
Keyword(s):  
Binding Capacity ◽  
Human Sperm ◽  
Neutrophil Extracellular Traps ◽  
Positive Control ◽  
Polymorphonuclear Neutrophils ◽  
Extracellular Dna ◽  
Dna Integrity ◽  
Extracellular Traps

Human spermatozoa activate neutrophil extracellular traps (NETs) in vitro. NETosis is an efficient mechanism through which polymorphonuclear neutrophils (PMN) capture sperm in vitro. The objective of this study was to establish the role of store-operated Ca+2 entry (SOCE) in human sperm-triggered NETs and its impact on sperm integrity and oocyte binding capacity. PMN isolated from donors were exposed to spermatozoa isolated from normozoospermic donors using the swim-up technique and were divided into the following groups: (1) sperm, (2) PMN, (3) PMN + sperm, (4) PMN (pretreated with 2-APB, SOCE inhibitor) + sperm, (5) (PMN + DNase) + sperm, and (6) (PMN + PMA) + sperm (positive control). NETs were quantified using PicoGreen® and visualised by scanning electron microscopy and immunofluorescence of extracellular DNA and neutrophil elastase. Plasma membrane, acrosome, and DNA integrity were analysed by flow cytometry, and oocyte binding was evaluated using the hemizona pellucida assay. Sperm-triggered NETosis negatively affected the sperm membrane and acrosome integrity and decreased the oocyte binding capacity. These effects were negated by an SOCE inhibitor, thus improving sperm function and achieving high oocyte binding capacity. The SOCE inhibitor significantly reduced NET formation compared with that in control PMN/sperm (P < 0.05). Collectively, these results advance the knowledge about the role of PMN in reproduction and will allow the development of strategies to block NET formation in situations of reduced fertilisation success.

scholarly journals A DNase from a Fungal Phytopathogen Is a Virulence Factor Likely Deployed as Counter Defense against Host-Secreted Extracellular DNA

mBio ◽  
2019 ◽  
Vol 10 (2) ◽  
Author(s):  
Hee-Jin Park ◽  
Weiwei Wang ◽  
Gilberto Curlango-Rivera ◽  
Zhongguo Xiong ◽  
Zeran Lin ◽  
...  
Keyword(s):  
Single Gene ◽  
Neutrophil Extracellular Traps ◽  
Extracellular Dna ◽  
Fungal Culture ◽  
Wild Type ◽  
Plant Host ◽  
Gene Encoding ◽  
Content Type ◽  
Extracellular Traps ◽  
Fungal Plant Pathogen

ABSTRACT Histone-linked extracellular DNA (exDNA) is a component of neutrophil extracellular traps (NETs). NETs have been shown to play a role in immune response to bacteria, fungi, viruses, and protozoan parasites. Mutation of genes encoding group A Streptococcus extracellular DNases (exDNases) results in reduced virulence in animals, a finding that implies that exDNases are deployed as counter defense against host DNA-containing NETs. Is the exDNA/exDNase mechanism also relevant to plants and their pathogens? It has been demonstrated previously that exDNA is a component of a matrix secreted from plant root caps and that plants also carry out an extracellular trapping process. Treatment with DNase I destroys root tip resistance to infection by fungi, the most abundant plant pathogens. We show that the absence of a single gene encoding a candidate exDNase results in significantly reduced virulence of a fungal plant pathogen to its host on leaves, the known infection site, and on roots. Mg2+-dependent exDNase activity was demonstrated in fungal culture filtrates and induced when host leaf material was present. It is speculated that the enzyme functions to degrade plant-secreted DNA, a component of a complex matrix akin to neutrophil extracellular traps of animals. IMPORTANCE We document that the absence of a single gene encoding a DNase in a fungal plant pathogen results in significantly reduced virulence to a plant host. We compared a wild-type strain of the maize pathogen Cochliobolus heterostrophus and an isogenic mutant lacking a candidate secreted DNase-encoding gene and demonstrated that the mutant is reduced in virulence on leaves and on roots. There are no previous reports of deletion of such a gene from either an animal or plant fungal pathogen accompanied by comparative assays of mutants and wild type for alterations in virulence. We observed DNase activity, in fungal culture filtrates, that is Mg2+ dependent and induced when plant host leaf material is present. Our findings demonstrate not only that fungi use extracellular DNases (exDNases) for virulence, but also that the relevant molecules are deployed in above-ground leaves as well as below-ground plant tissues. Overall, these data provide support for a common defense/counter defense virulence mechanism used by animals, plants, and their fungal and bacterial pathogens and suggest that components of the mechanism might be novel targets for the control of plant disease.

Neutrophil Extracellular Traps (NETs) in Patients with Congenital Neutropenia

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 15-15
Author(s):  
Christine Happle ◽  
Manuela Germeshausen ◽  
Cornelia Zeidler ◽  
Karl Welte ◽  
Julia Skokowa
Keyword(s):  
Peripheral Blood ◽  
Neutrophil Elastase ◽  
Myeloid Cells ◽  
Neutrophil Extracellular Traps ◽  
Extracellular Dna ◽  
Lower Amount ◽  
Congenital Neutropenia ◽  
Aberrant Expression ◽  
Extracellular Traps ◽  
Activated Neutrophils

Abstract Abstract 15 Activated neutrophils kill microbes by phagocytosis and extracellular mechanisms, including neutrophil extracellular traps (NETs), which are composed of decondensed chromatin and granular proteins such as neutrophil elastase (NE) and cathepsin G. Enzymatic generation of reactive oxygen species (ROS) by NADPH oxidase and the release of serine proteases such as NE have been shown to be essential factors for NET formation. Patients with chronic granulmatous disease (CGD), who lack a normal generation of ROS, show a defective NET formation. Since myeloid cells of patients with severe congenital neutropenia (CN) show an aberrant expression pattern of granular proteases such as neutrophil elastase (NE) or myeloperoxidase, we aimed to analyse NET formation in activated neutrophils of these patients. CN is a heterogeneous hematological disorder, characterized by peripheral blood neutrophil counts below 0,2×109/l and a maturation arrest of myelopoiesis at the promyelocytic/myelocytic stage. 60% of CN patients harbor autosomal dominant mutations within the ELA2 gene encoding for NE, but also mutations in other genes (e.g. HAX1, G6PC3, WAS, GFI1, p14) have been found to be disease-causing. Previously, we described severely diminished levels of NE in myeloid cells of CN patients. Here, we aimed to explore NET formation in neutrophils of CN patients. Moreover, we intended to analyze the effects of a reduced ELA2 expression and gene mutations as seen in CN patients on NET formation in vitro. Granulocytes of CN patients undergoing G-CSF therapy were extracted by density centrifugation, stimulated with phorbol myristate acetate (PMA, 50 nM, up to 240 min) and then tested for NET formation. NETs were stained with an extracellular DNA dye or DAPI. Our analyses showed normal NET formation in peripheral blood granulocytes of two patients with HAX1-related neutropenia, whereas there was a significantly lower amount of NETs in two patients with ELA2 mutations. One further patient out of three CN patients with unknown mutations showed a reduced amount of NETs in bone marrow PMNs. To further evaluate the possible effect of downregulated ELA2 expression on NET formation, we transduced primary human CD34+ cells with a lentiviral-based shRNA construct downregulating the expression of NE. Subsequently, these cells were differentiated into granulocytes with a cytokine cocktail containing G-CSF and tested for their ability to form NETs. We found an almost completely abolished NET formation in cells transduced with ELA2 shRNA as compared to control cells. Hitherto, CGD is the only immunodeficiency with a clearly defective NET formation. Our results point to an impaired formation of NETs also in CN patients carrying ELA2 mutations. This supports the recent finding of a central role for NE in NET formation. Two patients with HAX1 related CN showed a normal ability to form NETs. Our further work will aim to better define the subgroup of CN patients defective in NET formation. Disclosures: No relevant conflicts of interest to declare.

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