scholarly journals Neutrophil extracellular trap formation and nuclease activity in septic patients

2019 ◽  
Author(s):  
Linda Cox ◽  
Kai Walstein ◽  
Lena Völlger ◽  
Friederike Reuner ◽  
Alexandra Bick ◽  
...  
Keyword(s):  
Healthy Volunteers ◽  
Nuclease Activity ◽  
Positive Control ◽  
Neutrophil Extracellular Trap ◽  
Average Percentage ◽  
Molecular Pattern ◽  
Extracellular Trap ◽  
Net Release

Abstract Background: There is little knowledge, whether in patients with sepsis neutrophil extracellular trap (NET) formation and NET degrading nuclease activity are altered. Thus, we tested the hypotheses that 1) NET formation from neutrophils of septic patients is increased compared to healthy volunteers, both without stimulation and following incubation with mitochondrial DNA (mtDNA), a damage-associated molecular pattern, or phorbol 12-myristate 13-acetate (PMA; positive control); and 2) serum nuclease activities are increased as well. Methods: We included 18 septic patients and 27 volunteers in this prospective observational trial while study was registered retrospectively. Blood was withdrawn and NET formation from neutrophils in vitro was quantified (average percentage of neutrophils showing NET formation on an image) without stimulation and following incubation with mtDNA (10µg/well) or PMA (25nmol). Serum nuclease activity was assessed using gel electrophoresis. Results: In contrast to our hypothesis, compared to healthy volunteers unstimulated NET release from neutrophils in septic patients was decreased by 46.3% (4.3%±1.8 SD vs. 8.2%±2.9, p≤0.0001) and 48.1% (4.9%±2.5 vs. 9.4%±5.2, p=0.002) after 2 and 4 hours of incubation. mtDNA further decreased NET formation in neutrophils from septic patients (4.7%±1.2 to 2.8%±0,8; p=0.03) but did not alter NET formation in neutrophils from volun-teers. As expected, PMA, as positive control, increased NET formation to 73.2% (±29.6) in septic patients and to 91.7% (±7.1) in volunteers after 4 hours of incubation (p=0.22). Serum nuclease activity (range: 0-6) was decreased in septic patients by 39.6% (3±2 vs 5±0; median and ICR, p=0.0001) compared to volunteers. Conclusions: Unstimulated NET formation and nuclease activity are decreased in septic patients and mtDNA can further reduce NET formation. Thus, neutrophils from septic patients show decreased NET formation in vitro despite diminished nuclease activity in vivo. Trail registration DRKS00007694, German Clinical Trials database (DRKS). Registered retrospectively 06.02.2015.

scholarly journals Neutrophil extracellular trap formation and nuclease activity in septic patients

2019 ◽  
Author(s):  
Linda Cox ◽  
Kai Walstein ◽  
Lena Völlger ◽  
Friederike Reuner ◽  
Alexandra Bick ◽  
...  
Keyword(s):  
Healthy Volunteers ◽  
Nuclease Activity ◽  
Positive Control ◽  
Neutrophil Extracellular Trap ◽  
Average Percentage ◽  
Molecular Pattern ◽  
Extracellular Trap ◽  
Net Release

Abstract Background: There is little knowledge, whether in patients with sepsis neutrophil extracellular trap (NET) formation and NET degrading nuclease activity are altered. Thus, we tested the hypotheses that 1) NET formation from neutrophils of septic patients is increased compared to healthy volunteers, both without stimulation and following incubation with mitochondrial DNA (mtDNA), a damage-associated molecular pattern, or phorbol 12-myristate 13-acetate (PMA; positive control); and 2) serum nuclease activities are increased as well. Methods: We included 18 septic patients and 27 volunteers in this prospective observational trial while study was registered retrospectively. Blood was withdrawn and NET formation from neutrophils in vitro was quantified (average percentage of neutrophils showing NET formation on an image) without stimulation and following incubation with mtDNA (10µg/well) or PMA (25nmol). Serum nuclease activity was assessed using gel electrophoresis. Results: In contrast to our hypothesis, compared to healthy volunteers unstimulated NET release from neutrophils in septic patients was decreased by 46.3% (4.3%±1.8 SD vs. 8.2%±2.9, p≤0.0001) and 48.1% (4.9%±2.5 vs. 9.4%±5.2, p=0.002) after 2 and 4 hours of incubation. mtDNA further decreased NET formation in neutrophils from septic patients (4.7%±1.2 to 2.8%±0,8; p=0.03) but did not alter NET formation in neutrophils from volun-teers. As expected, PMA, as positive control, increased NET formation to 73.2% (±29.6) in septic patients and to 91.7% (±7.1) in volunteers after 4 hours of incubation (p=0.22). Serum nuclease activity (range: 0-6) was decreased in septic patients by 39.6% (3±2 vs 5±0; median and ICR, p=0.0001) compared to volunteers. Conclusions: Unstimulated NET formation and nuclease activity are decreased in septic patients and mtDNA can further reduce NET formation. Thus, neutrophils from septic patients show decreased NET formation in vitro despite diminished nuclease activity in vivo. Trail registration DRKS00007694, German Clinical Trials database (DRKS). Registered retrospectively 06.02.2015.

scholarly journals Neutrophil extracellular trap-associated RNA and LL37 enable self-amplifying inflammation in psoriasis

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Franziska Herster ◽  
Zsofia Bittner ◽  
Nathan K. Archer ◽  
Sabine Dickhöfer ◽  
David Eisel ◽  
...  
Keyword(s):  
Neutrophil Extracellular Trap ◽  
Vicious Cycle ◽  
Inflammatory Skin Disease ◽  
Disease Exacerbation ◽  
Dna And Rna ◽  
Human Pmns ◽  
Extracellular Trap ◽  
Net Release

AbstractPsoriasis is an inflammatory skin disease with strong neutrophil (PMN) infiltration and high levels of the antimicrobial peptide, LL37. LL37 in complex with DNA and RNA is thought to initiate disease exacerbation via plasmacytoid dendritic cells. However, the source of nucleic acids supposed to start this initial inflammatory event remains unknown. We show here that primary murine and human PMNs mount a fulminant and self-propagating neutrophil extracellular trap (NET) and cytokine response, but independently of the canonical NET component, DNA. Unexpectedly, RNA, which is abundant in NETs and psoriatic but not healthy skin, in complex with LL37 triggered TLR8/TLR13-mediated cytokine and NET release by PMNs in vitro and in vivo. Transfer of NETs to naive human PMNs prompts additional NET release, promoting further inflammation. Our study thus uncovers a self-propagating vicious cycle contributing to chronic inflammation in psoriasis, and NET-associated RNA (naRNA) as a physiologically relevant NET component.

scholarly journals Potentiation of NETs release is novel characteristic of TREM-1 activation and the pharmacological inhibition of TREM-1 could prevent from the deleterious consequences of NETs release in sepsis

2021 ◽  
Author(s):  
Amir Boufenzer ◽  
Kevin Carrasco ◽  
Lucie Jolly ◽  
Benjamin Brustolin ◽  
Elisa Di-Pillo ◽  
...  
Keyword(s):  
Vascular Reactivity ◽  
Myeloid Cell ◽  
Neutrophil Extracellular Trap ◽  
Toll Like Receptor 4 ◽  
Genetic Ablation ◽  
Experimental Septic Shock ◽  
Net Release

AbstractDuring sepsis, neutrophil activation induces endothelial cell (EC) dysfunction partly through neutrophil extracellular trap (NET) release. The triggering receptor expressed on myeloid cell-1 (TREM-1) is an orphan immune receptor that amplifies the inflammatory response mediated by Toll-like receptor-4 (TLR4) engagement. Although the key role of TLR4 signaling in NETosis is known, the role of TREM-1 in this process has not yet been investigated. Here, we report that TREM-1 potentiates NET release by human and murine neutrophils and is a component of the NET structure. In contrast, pharmacologic inhibition or genetic ablation of TREM-1 decreased NETosis in vitro and during experimental septic shock in vivo. Moreover, isolated NETs were able to activate ECs and impair vascular reactivity, and these deleterious effects were dampened by TREM-1 inhibition. TREM-1 may, therefore, constitute a new therapeutic target to prevent NETosis and associated endothelial dysfunction.

scholarly journals Uremic serum damages endothelium by provoking excessive neutrophil extracellular trap formation

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Hoi Woul Lee ◽  
Victor Nizet ◽  
Jung Nam An ◽  
Hyung Seok Lee ◽  
Young Rim Song ◽  
...  
Keyword(s):  
Inflammatory Responses ◽  
Umbilical Vein ◽  
Composite Endpoint ◽  
Neutrophil Extracellular Trap ◽  
Intracellular Adhesion Molecule ◽  
Uremic Serum ◽  
Control Serum ◽  
Extracellular Trap

AbstractCardiovascular disease (CVD) is the leading cause of death in patients with chronic kidney disease (CKD). Endothelial cell (EC) dysfunction is a key CKD-specific risk factor; however, the mechanisms by which uremia harms the endothelium are still unclear. We report a role for excessive neutrophil extracellular trap (NET) formation induced by uremic serum on EC injury. Level of plasma nucleosome and myeloperoxidase-DNA, established in vivo markers of NETs, as well as intracellular adhesion molecule (ICAM)-1 were measured in hemodialysis (HD) patients and healthy volunteers (HV) and their prognostic role evaluated. For in vitro studies, HV-derived neutrophils and differentiated HL-60 cells by retinoic acid were used to determine the effect of uremic serum-induced NETs on human umbilical vein EC (HUVEC). The level of in vivo NETs was significantly higher in incident HD patients compared to HV, and these markers were strongly associated with ICAM-1. Specifically, nucleosome and ICAM-1 levels were independent predictors of a composite endpoint, all-cause mortality, or vascular access failure. In vitro, HD-derived uremic serum significantly increased NET formation both in dHL-60 and isolated neutrophils compared to control serum, and these NETs decreased EC viability and induced their apoptosis. In addition, the level of ICAM-1, E-selectin and von Willebrand factor in HUVEC supernatant was significantly increased by uremic serum-induced NETs compared to control serum-induced NETs. Dysregulated neutrophil activities in the uremic milieu may play a key role in vascular inflammatory responses. The high mortality and CVD rates in ESRD may be explained in part by excessive NET formation leading to EC damage and dysfunction.

scholarly journals Cannabidiol Modifies the Formation of NETs in Neutrophils of Psoriatic Patients

2020 ◽  
Vol 21 (18) ◽  
pp. 6795
Author(s):  
Piotr Wójcik ◽  
Marzena Garley ◽  
Adam Wroński ◽  
Ewa Jabłońska ◽  
Elżbieta Skrzydlewska
Keyword(s):  
Healthy Subjects ◽  
Antioxidant Properties ◽  
Neutrophil Extracellular Trap ◽  
Oxygen Species ◽  
Extracellular Trap ◽  
Positive Effect ◽  
Healthy Participants ◽  
Lps Treatment

Psoriasis is associated with increased production of reactive oxygen species which leads to oxidative stress. As antioxidants can provide protection, the aim of this study was to evaluate the effects of cannabidiol (CBD) on neutrophil extracellular trap (NET) formation in psoriatic and healthy neutrophils. Important markers of NETosis were measured in healthy and psoriatic neutrophils after incubation with CBD, lipopolysaccharide (LPS), and LPS + CBD). The percentage of neutrophils undergoing NETosis and the level of NETosis markers (cfDNA, MPO, elastase) were higher in the neutrophils and blood plasma of psoriatic patients, compared to controls. After LPS treatment, all of the markers of NETosis, except elastase, and p47 and citrullinated histones, were increased in samples from healthy subjects and psoriasis patients. CBD reduced the concentrations of NETosis markers. This led to a reduction in NETosis, which was more pronounced in psoriatic neutrophils and neutrophils treated with LPS in both psoriatic and healthy participants. These results suggest that psoriatic patients neutrophils are at a higher risk of NETosis both in vitro and in vivo. CBD reduces NETosis, mainly in psoriatic neutrophils, possibly due to its antioxidant properties. The anti-NET properties of CBD suggest the positive effect of CBD in the treatment of autoimmune diseases.

scholarly journals Uremic Serum Damages Endothelium by Provoking Excessive Neutrophil Extracellular Trap Formation

2021 ◽  
Author(s):  
Hoi Woul Lee ◽  
Victor Nizet ◽  
Jung Nam An ◽  
Hyung Seok Lee ◽  
Young Rim Song ◽  
...  
Keyword(s):  
Inflammatory Responses ◽  
Umbilical Vein ◽  
Composite Endpoint ◽  
Neutrophil Extracellular Trap ◽  
Intracellular Adhesion Molecule ◽  
Uremic Serum ◽  
Control Serum ◽  
Extracellular Trap

Abstract Cardiovascular disease (CVD) is the leading cause of death in patients with chronic kidney disease (CKD). Endothelial cell (EC) dysfunction is a key CKD-specific risk factor; however, the mechanisms by which uremia harms the endothelium are still unclear. We report a role for excessive neutrophil extracellular trap (NET) formation induced by uremic serum on EC injury. Level of plasma nucleosome and myeloperoxidase-DNA, established in vivo markers of NETs, as well as intracellular adhesion molecule (ICAM)-1 were measured in hemodialysis (HD) patients and healthy volunteers (HV) and their prognostic role evaluated. For in vitro studies, we differentiated HL-60 cells into neutrophil-like cells (dHL-60) by applying retinoic acid and determined the effect of uremic serum on these dHL-60 and human umbilical vein EC (HUVEC). The level of in vivo NETs was significantly higher in incident HD patients compared to HV, and these markers were strongly associated with ICAM-1. Specifically, nucleosome and ICAM-1 levels were independent predictors of a composite endpoint, all-cause mortality or vascular access failure. In vitro, HD-derived serum significantly increased NET formation by dHL-60, and these NETs decreased EC viability and induced their apoptosis. In addition, the ICAM-1 level in HUVEC supernatant was significantly increased by uremic serum-induced NETs compared to control serum-induced NETs. Dysregulated neutrophil activities in the uremic milieu may play a key role in vascular inflammatory responses. The high mortality and CVD rates in ESRD may be explained in part by excessive NET formation leading to EC damage and dysfunction.

scholarly journals Immunoregulation of Neutrophil Extracellular Trap Formation by Endothelial-Derived p33 (gC1q Receptor)

2017 ◽  
Vol 10 (1) ◽  
pp. 30-43 ◽  
Author(s):  
Ariane Neumann ◽  
Praveen Papareddy ◽  
Johannes Westman ◽  
Ole Hyldegaard ◽  
Johanna Snäll ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Enzymatic Activity ◽  
Streptococcus Pyogenes ◽  
Neutrophil Extracellular Traps ◽  
Neutrophil Extracellular Trap ◽  
Defence Mechanism ◽  
Extracellular Traps ◽  
Molecular Pattern ◽  
Extracellular Trap

The formation of neutrophil extracellular traps (NETs) is a host defence mechanism, known to facilitate the entrapment and growth inhibition of many bacterial pathogens. It has been implicated that the translocation of myeloperoxidase (MPO) from neutrophilic granules to the nucleus is crucial to this process. Under disease conditions, however, excessive NET formation can trigger self-destructive complications by releasing pathologic levels of danger-associated molecular pattern molecules (DAMPs). To counteract such devastating immune reactions, the host has to rely on precautions that help circumvent these deleterious effects. Though the induction of DAMP responses has been intensively studied, the mechanisms that are used by the host to down-regulate them are still not understood. In this study, we show that p33 is an endothelial-derived protein that has the ability to annul NET formation. We found that the expression of human p33 is up-regulated in endothelial cells upon infections with Streptococcus pyogenes bacteria. Using tissue biopsies from a patient with streptococcal necrotising fasciitis, we monitored co-localisation of p33 with MPO. Further in vitro studies revealed that p33 is able to block the formation of DAMP-induced NET formation by inhibiting the enzymatic activity of MPO. Additionally, mice challenged with S. pyogenes bacteria demonstrated diminished MPO activity when treated with p33. Together, our results demonstrate that host-derived p33 has an important immunomodulating function that helps to counterbalance an overwhelming DAMP response.

In Vitro and In Vivo Neutralizing Activity of Uvaria chamae Leaves Fractions on the Venom of Naja nigricollis in Albino Rat and Bovine Blood

2020 ◽  
Vol 14 (4) ◽  
pp. 295-311
Author(s):  
Ada Gabriel ◽  
Mamman Mohammed ◽  
Mohammed G. Magaji ◽  
Yusuf P. Ofemile ◽  
Ameh P. Matthew ◽  
...  
Keyword(s):  
Ethyl Acetate ◽  
Neglected Tropical Diseases ◽  
Lethal Dose ◽  
Positive Control ◽  
Haemolytic Activity ◽  
Cytotoxic Activities ◽  
Albino Rat ◽  
Aqueous Residue

Background: Snakebite envenomation is a global priority ranked top among other neglected tropical diseases. There is a folkloric claim that Uvaria chamae is beneficial for the management of snakebite and wounds in African ethnobotanical surveys. Besides, there are many registered patents asserting the health benefits of U. chamae. Objective: This study aimed to investigate U. chamae’s potentials and identify candidates for the development of tools for the treatment and management of N. nigricollis envenomation. Methods: Freshly collected U. chamae leaves were air-dried, powdered, and extracted in methanol. The median lethal dose of the extract was determined and further fractionated with n-hexane, n-butanol and ethyl acetate. Each fraction was tested for neutralizing effect against venom-induced haemolytic, fibrinolytic, hemorrhagic, and cytotoxic activities. Results: U. chamae fractions significantly (p<0.05) neutralized the haemolytic activity of N. nigricollis venom in n-butanol; 31.40%, n-hexane; 33%, aqueous residue; 39.60% and ethyl acetate; 40.70% at the concentration of 100mg/ml of each fraction against 10mg/ml of the snake venom when compared to the positive control. The fibrinolytic activity of N. nigricollis venom was significantly (p<0.05) neutralized in n-hexane at 73.88%, n-butanol; 72.22% and aqueous residue; 72.22% by the fractions of U. chamae. In addition, haemorrhagic activity of N. nigricollis venom was significantly (p<0.05) neutralized by U. chamae fractions at the concentrations of 100mg/ml, 200mg/ml and 400mg/ml except for n-butanol and aqueous residues at 400 mg/ml. Conclusion: U. chamae leaves fractions possess a high level of protection against N. nigricollis venoms-induced lethality and thus validate the pharmacological rationale for its usage in the management of N. nigricollis envenomation.

scholarly journals Therapeutic effects of sesamolin on leukemia induced by WEHI-3B in model mice

2021 ◽  
Vol 64 (1) ◽  
Author(s):  
Senthil Nagarajan ◽  
Jae Kwon Lee
Keyword(s):  
Nk Cell ◽  
Neoplastic Cell ◽  
Positive Control ◽  
Cytolytic Activity ◽  
Leukemic Cells ◽  
Therapeutic Effects ◽  
Control Drug ◽  
Lysis Activity

AbstractSesamolin is one of the lignans derived from sesame oil. It has demonstrated significant antioxidant, anti-aging, and anti-mutagenic properties. It also reportedly augments natural killer (NK) cell lysis activity. We previously reported that sesamolin also exerts anticancer effects in vitro and induces enhanced NK cell cytolytic activity against tumor cells. Herein, we aimed to determine the mechanism by which sesamolin prevents and retards tumorigenesis in BALB/c mouse models of leukemia induced by murine (BALB/c) myelomonocytic leukemia WEHI-3B cells. Banded neutrophils, myeloblasts, and monocytic leukemic cells were more abundant in the leukemia model than in normal mice. Sesamolin decreased the number of leukemic cells by almost 60% in the leukemia model mice in vivo; additionally, sesamolin and the positive control drug, vinblastine, similarly hindered neoplastic cell proliferation. Spleen samples were ~ 4.5-fold heavier in leukemic mice than those obtained from normal mice, whereas spleen samples obtained from leukemic mice treated with sesamolin had a similar weight to those of normal mice. Moreover, sesamolin induced a twofold increase in the cytotoxic activity of leukemic mouse NK cells against WEHI-3B cells. These results indicated that sesamolin exerts anti-leukemic effects in vivo.

scholarly journals In Vitro Effects of Sulforaphane on Interferon-Driven Inflammation and Exploratory Evaluation in Two Healthy Volunteers

Molecules ◽  
2021 ◽  
Vol 26 (12) ◽  
pp. 3602
Author(s):  
Elena Genova ◽  
Maura Apollonio ◽  
Giuliana Decorti ◽  
Alessandra Tesser ◽  
Alberto Tommasini ◽  
...  
Keyword(s):  
Healthy Volunteers ◽  
Supportive Therapy ◽  
P Value ◽  
Type I ◽  
Interferon Signature ◽  
Interferon Stimulated Genes ◽  
Immune System Activation ◽  
In Vitro Effects

Interferonopathies are rare genetic conditions defined by systemic inflammatory episodes caused by innate immune system activation in the absence of pathogens. Currently, no targeted drugs are authorized for clinical use in these diseases. In this work, we studied the contribution of sulforaphane (SFN), a cruciferous-derived bioactive molecule, in the modulation of interferon-driven inflammation in an immortalized human hepatocytes (IHH) line and in two healthy volunteers, focusing on STING, a key-component player in interferon pathway, interferon signature modulation, and GSTM1 expression and genotype, which contributes to SFN metabolism and excretion. In vitro, SFN exposure reduced STING expression as well as interferon signature in the presence of the pro-inflammatory stimulus cGAMP (cGAMP 3 h vs. SFN+cGAMP 3 h p value < 0.0001; cGAMP 6 h vs. SFN+cGAMP 6 h p < 0.001, one way ANOVA), restoring STING expression to the level of unstimulated cells. In preliminary experiments on healthy volunteers, no appreciable variations in interferon signature were identified after SFN assumption, while only in one of them, presenting the GSTM1 wild type genotype related to reduced SFN excretion, could a downregulation of STING be recorded. This study confirmed that SFN inhibits STING-mediated inflammation and interferon-stimulated genes expression in vitro. However, only a trend towards the downregulation of STING could be reproduced in vivo. Results obtained have to be confirmed in a larger group of healthy individuals and in patients with type I interferonopathies to define if the assumption of SFN could be useful as supportive therapy.

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