scholarly journals NETs Enhance STING To Promote Surgical Adhesion

2021 ◽  
Author(s):  
Qiongyu Hu ◽  
Xiaofei Shen ◽  
Meng Wang ◽  
Xiaofeng Lu ◽  
Song Liu ◽  
...  
Keyword(s):  
Early Stage ◽  
Neutrophil Extracellular Traps ◽  
Postoperative Adhesion ◽  
Peptidylarginine Deiminase ◽  
Extracellular Traps ◽  
Dnase 1 ◽  
Neutrophil Depletion ◽  
Essential Enzyme ◽  
Pad Inhibitor ◽  
Pharmacologic Inhibition

Abstract Background Postoperative adhesion (PA) following abdominal surgery may cause bowel obstruction, chronic pain, infertility, or even death. Knowledge of adhesion biology is limited, and preventive agents in clinical trials have failed to achieve efficacy. Results In the present study, we showed that neutrophils accumulate in the injured peritoneum at early stage of PA, and neutrophils within the ischemic buttons undergo cell death and form neutrophil extracellular traps (NETs) that contribute to PA. Neutrophil depletion reduces adhesion burden at 7 days after adhesion induction. Peptidylarginine deiminase 4 (PAD4), an essential enzyme for NET formation, is increased in ischemic buttons. Degradation of NETs by DNase 1 and suppression of NET formation by pharmacologic inhibition of PAD4 alleviated adhesion burden, collogen deposition and fibrosis formation. Mechanistically, administration of DNase I and PAD inhibitor reduces STING-mediated inflammatory response. STING deficiency attenuates adhesion burden, collogen deposition, and α-SMA production in the adhesive tissues at 7 days after surgery. Conclusions Collectively, our findings reveal NETs/STING signaling as a therapeutic target to prevent PA.

scholarly journals Neutrophil Extracellular Traps and Microcrystals

2017 ◽  
Vol 2017 ◽  
pp. 1-7 ◽  
Author(s):  
Balázs Rada
Keyword(s):  
Early Stage ◽  
Neutrophil Extracellular Traps ◽  
Calcium Pyrophosphate ◽  
Cholesterol Crystals ◽  
Extracellular Traps ◽  
Calcium Pyrophosphate Dehydrate ◽  
Innate Immune Mechanism ◽  
Silica Crystals ◽  
Net Release ◽  
Urate Crystals

Neutrophil extracellular traps represent a fascinating mechanism by which PMNs entrap extracellular microbes. The primary purpose of this innate immune mechanism is thought to localize the infection at an early stage. Interestingly, the ability of different microcrystals to induce NET formation has been recently described. Microcrystals are insoluble crystals with a size of 1–100 micrometers that have different composition and shape. Microcrystals have it in common that they irritate phagocytes including PMNs and typically trigger an inflammatory response. This review is the first to summarize observations with regard to PMN activation and NET release induced by microcrystals. Gout-causing monosodium urate crystals, pseudogout-causing calcium pyrophosphate dehydrate crystals, cholesterol crystals associated with atherosclerosis, silicosis-causing silica crystals, and adjuvant alum crystals are discussed.

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 Neutrophil extracellular traps promote tPA-induced brain hemorrhage via cGAS in mice with stroke

Blood ◽  
2021 ◽  
Author(s):  
Ranran Wang ◽  
Yuanbo Zhu ◽  
Zhongwang Liu ◽  
Luping Chang ◽  
Xiaofei Bai ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Thrombolytic Therapy ◽  
Clinical Problem ◽  
Neutrophil Extracellular Traps ◽  
Artery Occlusion ◽  
Type I ◽  
Brain Hemorrhage ◽  
Extracellular Traps ◽  
Dnase 1

Intracerebral hemorrhage associated with thrombolytic therapy with tissue plasminogen activator (tPA) in acute ischemic stroke continues to present a major clinical problem. Here, we report that infusion of tPA resulted in a significant increase in markers of neutrophil extracellular traps (NETs) in the ischemic cortex and plasma of mice subjected to photothrombotic middle cerebral artery occlusion. Peptidylarginine deiminase 4 (PAD4), a critical enzyme for NET formation, is also significantly upregulated in the ischemic brains in tPA-treated mice. Blood-brain barrier (BBB) disruption following ischemic challenge in an in vitro model of BBB was exacerbated after exposure to NETs. Importantly, disruption of NETs by DNase 1 or inhibition of NET production by PAD4 deficiency restored tPA-induced loss of BBB integrity and consequently decreased tPA-associated brain hemorrhage after ischemic stroke. Furthermore, either DNase 1 or PAD4 deficiency reversed tPA-mediated upregulation of the DNA sensor cyclic GMP-AMP (cGAMP) synthase (cGAS). Administration of cGAMP after stroke abolished DNase 1-mediated downregulation of the STING pathway and type I interferon (IFN) production, and blocked the antihemorrhagic effect of DNase 1 in tPA-treated mice. We also show that tPA-associated brain hemorrhage after ischemic stroke was significantly reduced in cGas-/- mice. Collectively, these findings demonstrate that NETs significantly contribute to tPA-induced BBB breakdown in ischemic brain, and suggest that targeting NETs or cGAS may ameliorate thrombolytic therapy for ischemic stroke by reducing tPA-associated hemorrhage.

scholarly journals Neutrophil Extracellular Traps Generation Relates with Early Stage and Vascular Complications in Systemic Sclerosis

2020 ◽  
Vol 9 (7) ◽  
pp. 2136 ◽  
Author(s):  
Kevin Didier ◽  
Delphine Giusti ◽  
Sebastien Le Jan ◽  
Christine Terryn ◽  
Celine Muller ◽  
...  
Keyword(s):  
Systemic Sclerosis ◽  
Early Stage ◽  
Systemic Disease ◽  
Vascular Complications ◽  
Neutrophil Extracellular Traps ◽  
Digital Ulcers ◽  
Serum Factors ◽  
Net Production ◽  
Extracellular Traps ◽  
Enhanced Production

Systemic sclerosis (SSc) is a systemic disease characterized by a great clinical and immunological heterogeneity whose pathophysiology is still being unraveled. Recently, innate immunity has been proposed to participate to the pathogenesis of SSc. In this study, we investigated the release of neutrophil extracellular traps (NETs) according to patient phenotype. Polymorphonuclear neutrophils (PMN) from 34 SSc patients and 26 healthy controls were stimulated by serum from SSc or healthy subject. NETs were visualized using epifluorescence microscope after DNA, myeloperoxidase, and Histone H3 tagging. Area of NETs were quantified using an original macro running in ImageJ® software. PMN from SSc patients were significantly more prone to releasing NETs than control PMN after autologous stimulation. PMN from patients with severe vascular complications (pulmonary arterial hypertension, digital ulcers) produced more NETs than PMN from other SSc patients and their aberrant NET production appeared to be sustained over time. In patients with pulmonary interstitial disease or extensive cutaneous fibrosis, NET production was high at an early stage of the disease before progressively decreasing. Both serum factors and PMN activation status were involved in the enhanced production of NETs in SSc. Consequently, neutrophils and especially NETosis represent new physiopathological and therapeutic fields in SSc.

scholarly journals Neutrophil extracellular traps impair regeneration

2020 ◽  
Author(s):  
Eric Wier ◽  
Mayumi Asada ◽  
Gaofeng Wang ◽  
Martin P. Alphonse ◽  
Ang Li ◽  
...  
Keyword(s):  
Hair Follicle ◽  
De Novo ◽  
Neutrophil Extracellular Traps ◽  
Neutrophil Extracellular Trap ◽  
Major Health ◽  
Net Production ◽  
Extracellular Traps ◽  
Single Cell Rna Sequencing ◽  
Neutrophil Depletion ◽  
Extracellular Trap

AbstractFibrosis is a major health burden across diseases and organs. To remedy, we study wound induced hair follicle regeneration (WIHN) as a model of non-fibrotic healing that instead recapitulates embryogenesis for de novo hair follicle morphogenesis after wounding. We have previously demonstrated that TLR3 promotes WIHN through binding dsRNA, but the source of which is still unclear. Here, we demonstrate that multiple distinct contexts of high WIHN all show a strong neutrophil signature, and given the likelihood of nuclear dsRNA release during the production of neutrophil extracellular trap (NETs), we hypothesized that neutrophils and NETs might promote WIHN. Consistent with this, in addition to the presence of neutrophils shortly after wounding, neutrophils remain within the wound after the barrier is reestablished, where they produce extracellular traps (NETs) that likely release spliceosomal U1 dsRNA. Contrary to our hypothesis, genetic models of neutrophil depletion show enhanced WIHN. Pad4 null mice that are defective in NET production also augment WIHN. Finally, using single-cell RNA sequencing, we identified a dramatic increase in neutrophil populations in the wound beds of low regenerating Tlr3-/- mice. Taken together, these results demonstrate that although neutrophils are stimulated by a common pro-regenerative cue, their presence and NETs can hinder regeneration.

scholarly journals The total terpenoids of Celastrus orbiculatus (TTC) inhibit NOX-dependent formation of PMA-induced neutrophil extracellular traps (NETs)

2018 ◽  
Vol 16 ◽  
pp. 205873921880566
Author(s):  
Li Tao ◽  
Min Xu ◽  
Yanqing Liu
Keyword(s):  
Enzymatic Activity ◽  
Early Stage ◽  
Neutrophil Extracellular Traps ◽  
Human Neutrophils ◽  
Ros Generation ◽  
Ros Production ◽  
Celastrus Orbiculatus ◽  
Traditional Chinese Herbal Medicine ◽  
Extracellular Traps ◽  
Anti Inflammatory

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.

scholarly journals Origin of Circulating Free DNA in Sepsis: Analysis of the CLP Mouse Model

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Shigeto Hamaguchi ◽  
Yukihiro Akeda ◽  
Norihisa Yamamoto ◽  
Masafumi Seki ◽  
Kouji Yamamoto ◽  
...  
Keyword(s):  
Histone H3 ◽  
Cecal Ligation ◽  
Physiological Role ◽  
Neutrophil Extracellular Traps ◽  
Control Groups ◽  
Extracellular Traps ◽  
Circulating Free Dna ◽  
Free Dna ◽  
Neutrophil Depletion

Recently, it has been reported that circulating free DNA (cf-DNA) in the blood is increased in various infectious diseases, including sepsis. Moreover, a relationship between cf-DNA and neutrophil extracellular traps (NETs) has been suggested. However, it is still unclear what the source and physiological role of cf-DNA in sepsis are. In this study, we examined the source of cf-DNA by detecting citrullinated histone H3, a characteristic feature of NET formation, in cecal ligation and puncture- (CLP-)operated mice. In addition, neutrophil depletion using anti-Ly6G antibodies was performed to assess the association between neutrophils and cf-DNA. Increased cf-DNA levels were observed only in CLP mice and not in the control groups; the qPCR findings revealed that the cf-DNA was mainly host-derived, even in bacteremic conditions. Citrullinated histone H3 was not increased in the neutrophils upon CLP, and the depletion of neutrophils showed limited effects on decreasing the amount of cf-DNA. Taken together, these results suggested that elevated cf-DNA levels during early-phase sepsis may represent a candidate biomarker for the severity of sepsis and that, contrary to previous findings, cf-DNA is not derived from neutrophils or NETs.

Inhibition of PAD4 mediated neutrophil extracellular traps prevents fibrotic osseointegration failure in a tibial implant murine model

2021 ◽  
Vol 103-B (7 Supple B) ◽  
pp. 135-144
Author(s):  
Emile-Victor Kuyl ◽  
Fei Shu ◽  
Branden R. Sosa ◽  
Juan D. Lopez ◽  
Di Qin ◽  
...  
Keyword(s):  
Aseptic Loosening ◽  
Murine Model ◽  
Innate Immune System ◽  
Neutrophil Extracellular Traps ◽  
Innate Immune ◽  
Bone Implant ◽  
Extracellular Traps ◽  
Fibrotic Tissue ◽  
Dnase 1 ◽  
Biological Target

Aims Aseptic loosening is a leading cause of uncemented arthroplasty failure, often accompanied by fibrotic tissue at the bone-implant interface. A biological target, neutrophil extracellular traps (NETs), was investigated as a crucial connection between the innate immune system’s response to injury, fibrotic tissue development, and proper bone healing. Prevalence of NETs in peri-implant fibrotic tissue from aseptic loosening patients was assessed. A murine model of osseointegration failure was used to test the hypothesis that inhibition (through Pad4-/- mice that display defects in peptidyl arginine deiminase 4 (PAD4), an essential protein required for NETs) or resolution (via DNase 1 treatment, an enzyme that degrades the cytotoxic DNA matrix) of NETs can prevent osseointegration failure and formation of peri-implant fibrotic tissue. Methods Patient peri-implant fibrotic tissue was analyzed for NETs biomarkers. To enhance osseointegration in loose implant conditions, an innate immune system pathway (NETs) was either inhibited ( Pad4-/- mice) or resolved with a pharmacological agent (DNase 1) in a murine model of osseointegration failure. Results NETs biomarkers were identified in peri-implant fibrotic tissue collected from aseptic loosening patients and at the bone-implant interface in a murine model of osseointegration failure. Inhibition ( Pad4-/- ) or resolution (DNase 1) of NETs improved osseointegration and reduced fibrotic tissue despite loose implant conditions in mice. Conclusion This study identifies a biological target (NETs) for potential noninvasive treatments of aseptic loosening by discovering a novel connection between the innate immune system and post-injury bone remodelling caused by implant loosening. By inhibiting or resolving NETs in an osseointegration failure murine model, fibrotic tissue encapsulation around an implant is reduced and osseointegration is enhanced, despite loose implant conditions. Cite this article: Bone Joint J 2021;103-B(7 Supple B):135–144.

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):  
Dna Cleavage ◽  
Underlying Mechanism ◽  
Causative Factor ◽  
Neutrophil Extracellular Traps ◽  
Neutrophil Recruitment ◽  
Triceps Surae ◽  
Extracellular Dna ◽  
Extracellular Traps ◽  
Neutrophil Depletion ◽  
Triceps Surae Muscles

Abstract Accumulation of uric acid (UA) during muscular trauma is a causative factor involved in the development of muscle hyperalgesia. Neutrophil extracellular traps (NETs), DNA-based reticular structures to capture UA, play a central role in the pain onset of gout attacks; however, the involvement of NETs via the elevation of local UA level in muscle hyperalgesia due to overuse injuries remains unknown. The triceps surae muscles (TSMs) in the unilateral hindlimb of mice were electrically stimulated to induce excessive muscle contraction. Mechanical withdrawal thresholds, tissue UA levels, neutrophil recruitment, protein amount of citrullinated histone 3 (citH3), a major marker of NETs, were investigated. Furthermore, whether neutrophil depletion, extracellular DNA cleavage, and administration of the urate-lowering agent febuxostat could improve muscle hyperalgesia due to NET formation was examined. CitH3 expression upon neutrophil recruitment significantly increased in the stimulated TSMs with an increase in tissue UA levels, whereas febuxostat administration improved muscle hyperalgesia with decreases in citH3 and tissue UA levels, as observed in neutrophil depletion and extracellular DNA digestion. The underlying mechanism of muscle hyperalgesia associated with locally recruited neutrophils forming NETs due to the increased tissue UA levels potentially plays a significant role in creating a vicious circle of muscle pain.

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.

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