The formation of neutrophil extracellular traps induced by antineutrophil cytoplasmic autoantibodies has been implicated in the pathogenesis of antineutrophil cytoplasmic autoantibody-associated vasculitis. Kraaij et al. now provide evidence that excessive neutrophil extracellular trap formation in vitro induced by sera from patients with antineutrophil cytoplasmic autoantibody-associated vasculitis is associated with active disease but is not dependent on the presence of antineutrophil cytoplasmic autoantibodies. ...

Neutrophil cell trapping bacteria. Coloured scanning electron micrograph (SEM) of bacteria (rod-shaped) being trapped by a neutrophil cell. The neutrophil cell (a type of white blood cell) has trapped the bacteria with extruded material that forms a net-like structure called a NET (neutrophil extracellular trap). This method of cellular defence was first discovered in 2004. These are Shigella sp. bacteria, one of the causes of dysentery, a severe intestinal inflammation. - Stock Image P276/0186

Staphylococcus aureus is a commensal organism in approximately 30% of the human population and colonization is a significant risk factor for invasive infection. As a result of this, there is a great need to better understand how S. aureus overcomes human immunity. Neutrophils are essential during the innate immune response to S. aureus, yet this microorganism uses multiple evasion strategies to avoid killing by these immune cells, perhaps the most catastrophic of which is the rapid induction of neutrophil cell death. The aim of this study was to better understand the mechanisms underpinning S. aureus-induced neutrophil lysis, and how this contributes to pathogenesis in a whole organism model of infection. To do this we screened the genome-wide Nebraska Transposon Mutant Library (NTML) in the community acquired methicillin resistant S. aureus strain, USA300, for decreased ability to induce neutrophil cell lysis. Out of 1,920 S. aureus mutants, a number of known regulators of cell lysis ...

Optic atrophy 1 (OPA1) is a mitochondrial inner membrane protein that has an important role in mitochondrial fusion and structural integrity. Dysfunctional OPA1 mutations cause atrophy of the optic nerve leading to blindness. Here, we show that OPA1 has an important role in the innate immune system. Using conditional knockout mice lacking Opa1 in neutrophils (Opa1N∆), we report that lack of OPA1 reduces the activity of mitochondrial electron transport complex I in neutrophils. This then causes a decline in adenosine-triphosphate (ATP) production through glycolysis due to lowered NAD+ availability. Additionally, we show that OPA1-dependent ATP production in these cells is required for microtubule network assembly and for the formation of neutrophil extracellular traps. Finally, we show that Opa1N∆ mice exhibit a reduced antibacterial defense capability against Pseudomonas aeruginosa. Optic atrophy 1 (OPA1) is known to be important for mitochondrial fusion and structural integrity. Here, using OPA1

Bacteria colony counts in peripheral blood and in bronchoalveolar lavage fluid (BALF) were also markedly decreased in PLD2−/− mice versus WT (Fig. 3 a). Bacteria released into the peritoneal cavity eventually make their way through the circulation and enter lung tissue, resulting in lung inflammation (Matute-Bello et al., 2001). Bacteria colony counts in lung tissues were also significantly decreased in PLD2−/− mice versus WT (Fig. 3 a). Live bacterial colony numbers were significantly increased in liver and spleen 24 h after CLP in WT mice compared with PLD2−/− mice (Fig. 3 a).. It was recently reported that neutrophils generate NETs to trap and kill invading bacteria (Brinkmann et al., 2004). To investigate the effect of PLD2 deficiency on NET formation, we stained neutrophils with SYTOX Green nucleic acid stain, a nonpermeable dye that stains nucleic acid, a primary component of NETs. Stimulation of neutrophils isolated from WT mice with ionomycin induced NET formation (Fig. 3 d). ...

Definition of neutrophil microbicidal assay in the Legal Dictionary - by Free online English dictionary and encyclopedia. What is neutrophil microbicidal assay? Meaning of neutrophil microbicidal assay as a legal term. What does neutrophil microbicidal assay mean in law?

Polymorphonuclear neutrophils, or granulocytes, are essential effector cells of the innate immune system against bacterial infections. Their role in sepsis has been long established as the primary phagocyte to clear the infectious process. In the early phase of sepsis, one observes a massive recruitment of immature neutrophils from the bone marrow into peripheral blood, the so-called band forms or left shift cells. Despite the daily clinical use of neutrophil band forms count in the care of septic patients and their abundance in septic blood, no information exists on the fate of these cells, nor on their capacity to mount an efficient innate immune response. It is the goal of this proposal to study the fate and the innate immune functions of immature neutrophils obtained in patients with early septic shock. Immature neutrophils will be separated from mature neutrophils. The following functions will be studied ex vivo in mature vs. immature neutrophils from a series of patients with severe ...

TY - JOUR. T1 - Role of arachidonyl triglycerides within lipid bodies in eicosanoid formation by human polymorphonuclear cells. AU - Johnson, Margaret M.. AU - Vaughn, Benjamin. AU - Triggiani, Massimo. AU - Swan, Dennis D.. AU - Fonteh, Alfred N.. AU - Chilton, Floyd H.. PY - 1999/1/1. Y1 - 1999/1/1. N2 - Increasing evidence suggests that the subcellular and glycerolipid localization of esterified arachidonic acid (AA) is a key factor in regulating its availability to lipases. The goal of the current study was to determine the potential of AA stored in triglycerides (TG) to serve as a substrate for lipases and 5-lipoxygenase during neutrophil (polymorphonuclear leukocytes, PMN) activation. PMN containing high concentrations of AA in TG were generated by culturing PMN in vitro with high concentrations of exogenous AA (eAA) for 12 h. Cellular AA increased 2- and 4-fold in PMNs incubated with 5 and 20 μM AA, respectively, and this increase was almost exclusively observed in neutral lipids (NL). ...

The mechanism of Ca2+ entry after ligand binding to receptors on the surface of non-excitable cells is a current focus of interest. Considerable attention has been given to Ca2+ influx induced by emptying of intracellular pools. Thapsigargin, an inhibitor of microsomal Ca(2+)-ATPase, is an important tool in inducing store-regulated Ca2+ influx. In the present paper we show that, at concentrations above 500 nM, thapsigargin also has an opposite effect: it inhibits store-regulated Ca2+ influx into Fura-2-loaded human neutrophil granulocytes. As thapsigargin has been frequently applied at concentrations up to 2 microM, its inhibitory action on plasma-membrane Ca2+ fluxes deserves consideration. ...

Powered by Pure, Scopus & Elsevier Fingerprint Engine™ © 2021 Elsevier B.V. We use cookies to help provide and enhance our service and tailor content. By continuing you agree to the use of cookies. ...

The chemokinetic inhibitory factor (CIF) is a recently described B-cell derived lymphokine that mediates a chemokinetic inhibitory effect on human polymorphonuclear leukocyte (PMN) migration. In the present report the interaction of CIF with the neutrophil plasma membrane was studied. Normal human peripheral blood neutrophils and purified neutrophil plasma membranes selectively removed biologic activity from CIF-containing concentrates obtained during the purification procedure from conditioned medium. Removal was obtained at both 4 degrees C and 37 degrees C. Furthermore, HL-60 cells treated with dimethyl sulfoxide removed CIF activity (granulocyte-like cells) but HL-60 cells treated with 12-O-tetradecanoylphorbol-13-acetate (macrophage-like cells) did not. Purified human blood monocytes, cells from the macrophage-like U-937 cell line and cells from the basophilic leukemia cell line KU-812 did not remove CIF. These studies suggest that neutrophils express specific binding sites for ...

To gain further insight into the effects of calcium influx on neutrophil chemotaxis, we depleted the calcium in the under-agarose chemotaxis models using a calcium-free solution and EGTA. We observed that the inhibitory effects of LPS on neutrophil chemotaxis were impaired in the presence of calcium-depleted medium (Fig. 3C). Moreover, using a calcium ionophore ionomycin to stimulate neutrophils, a sustained calcium influx was observed and chemoattractant-induced neutrophil chemotaxis was dramatically inhibited (SI Appendix, Fig. S7A). The sustained calcium influx appeared to be required for initiating stop signal of neutrophil chemotaxis. Previous reports displayed that intracellular calcium was necessary for neutrophil migration (19). Therefore, we further clarified the effects of calcium on neutrophil migration. Different chemoattractant-induced calcium mobilization patterns were found to be inconsistent (20, 21). We noted that different from stimulation of IL-8, a rapid increase in ...

Neutrophil extracellular traps (NETs) play an important role in innate immunity to microbial infections. NETs have been described in several species, but the molecular details of NET formation and their role in infection has not been addressed, partly because we lack optimal experimental models. Here we describe tools to investigate NET formation in neutrophils isolated from mice. Upon in vitro stimulation of wild-type mouse neutrophils with PMA, we analyzed 3 important steps in the process of NET formation: reactive oxygen species (ROS) production, NET cell death and NET release. As expected, neutrophils from NADPH oxidase-deficient mice failed to produce ROS and did not die nor release NETs upon stimulation. We found that neutrophils from several mouse strains produced NETs with different efficiency and that NET formation correlated with the amount of ROS produced. Activation with Candida albicans also resulted in ROS production and NET cell death. The hyphal form of this fungus induced NETs ...

JS Parmar, D Bilton, ER Chilvers, DA Lomas; The Selective Chemotactic Effect of α1-Antitrypsin Polymers for Human Peripheral Blood Neutrophils. Clin Sci (Lond) 1 July 2002; 103 (s47): 56P. doi: https://doi.org/10.1042/cs103056P. Download citation file:. ...

Our results uncovered an unexpected role for MPO to influence the fate of neutrophils and consequently the duration of inflammation. By suppressing the constitutive cell death program, MPO prolonged the life span of neutrophils, thereby delaying the resolution of inflammation. These actions were specific for MPO, because other azurophilic granule constituents lactoferrin and elastase failed to affect neutrophil apoptosis.. Consistent with the commitment of neutrophils to apoptosis, MPO at clinically relevant concentrations delayed, rather than blocked apoptosis, resulting in prolonged survival of human neutrophils in vitro. We confirmed that increasing plasma concentrations of MPO in rats to levels comparable to those detected in patients with inflammatory vascular diseases20,21 was sufficient to retard the apoptotic machinery in neutrophils as assayed ex vivo. Furthermore, MPO also suppressed apoptosis in neutrophils that had emigrated into the airways and delayed resolution of inflammation in ...

TY - JOUR. T1 - Plasminogen activator inhibitor-1 supports IL-8-mediated neutrophil transendothelial migration by inhibition of the constitutive shedding of endothelial IL-8/heparan sulfate/syndecan-1 complexes. AU - Marshall, Lindsay J.. AU - Ramdin, Lara S.P.. AU - Brooks, Teresa. AU - Charlton, Peter. AU - Shute, Janis K.. PY - 2003/8/15. Y1 - 2003/8/15. N2 - The endothelium is the primary barrier to leukocyte recruitment at sites of inflammation. Neutrophil recruitment is directed by transendothelial gradients of IL-8 that, in vivo, are bound to the endothelial cell surface. We have investigated the identity and function of the binding site(s) in an in vitro model of neutrophil transendothelial migration. In endothelial culture supernatants, IL-8 was detected in a trimolecular complex with heparan sulfate and syndecan-1. Constitutive shedding of IL-8 in this form was increased in the presence of a neutralizing Ab to plasminogen activator inhibitor-1 (PAI-1), indicating a role for endothelial ...

TY - JOUR. T1 - Organism-Specific Neutrophil-Endothelial Cell Interactions in Response to Escherichia coli, Streptococcus pneumoniae, and Staphylococcus aureus. AU - Moreland, Jessica G.. AU - Bailey, Gail. AU - Nauseef, William M.. AU - Weiss, Jerrold P.. PY - 2004/1/1. Y1 - 2004/1/1. N2 - The recruitment of polymorphonuclear leukocytes (PMNs) from the vascular space into the lung interstitium and airspace is an early step in the host innate immune response to bacterial invasion of these sites. To determine the ability of intact bacteria to directly elicit PMN migration across an endothelial monolayer, we studied in vitro migration of PMNs across a monolayer of human pulmonary microvascular endothelial cells in response to Streptococcus pneumoniae, Staphylococcus aureus, and Escherichia coli, as well as to purified E. coli LPS. Bacterial induction of PMN migration was dose dependent and elicited by ≥104 bacteria/ml of each of the species tested. Pretreatment of PMNs with blocking Abs to CD18 ...

Neutrophil superoxide anion production was measured in healthy subjects and in patients with quiescent and active Crohns disease using superoxide dismutase inhibitable cytochrome C reduction. Three stimuli were used: phorbol 12-myristate 13-acetate (PMA1), phorbol 20-oxo-20-deoxy 12-myristate 13-acetate (PMA2), and Candida albicans in serum. Normal neutrophils produced significantly more superoxide anion than Crohns disease neutrophils with both PMA1 (mean (SD) 9.6 (2.2) v 8.6 (1.8) nmol/10(6) cells/5 minutes, p = 0.04) and PMA2 (1.8 (0.8) v 0.8 (0.77) nmol/10(6) cells/5 minutes, p = 0.00004). With C albicans in serum, normal and Crohns disease neutrophils produced similar amounts of superoxide anion (4.4 (1.5) v 4.3 (1.7) nmol/10(6) cells/30 minutes, not significant). Results were independent of disease activity. Superoxide anion production by PMA-stimulated Crohns disease neutrophils is significantly lower than by normal neutrophils.. ...

Human granulocyte-macrophage colony-stimulating factor (GM-CSF) modulates the function of mature neutrophils by priming for enhanced chemotaxis and oxidative metabolism in response to N-formyl-methionyl-leucyl-phenylalanine (f-Met-Leu-Phe). Our studies establish a relationship between f-Met-Leu-Phe receptor number and affinity and neutrophil chemotaxis and oxidative metabolism. A brief (5- to 15-min) exposure to physiologic concentrations of GM-CSF (10 pM to 100 pM) enhances f-Met-Leu-Phe-induced neutrophil chemotaxis by 85%, correlating with a rapid threefold increase (46,000/cell to 150,000/cell) in high-affinity neutrophil f-Met-Leu-Phe receptors. More prolonged incubation (1 to 2 hr) of neutrophils with GM-CSF is accompanied by a change to low-affinity f-Met-Leu-Phe receptors (Kd = 29 nM to Kd = 99 nM) concomitant with priming for enhanced neutrophil oxidative metabolism. Moreover, enhanced chemotactic responses to f-Met-Leu-Phe are no longer evident after more prolonged incubation of ...

TY - JOUR. T1 - Neutrophil extracellular traps in autoimmune diseases. T2 - Trampas extracelulares de neutrófilos en enfermedades autoinmunes. AU - Monsalve, Diana M.. AU - Acosta-Ampudia, Yeny. AU - Ramírez-Santana, Carolina. AU - Polo, José Fernando. AU - Anaya, Juan Manuel. PY - 2020/10/1. Y1 - 2020/10/1. N2 - Neutrophils play an important role in immune defence against several pathogens. These cells actively participate in the innate immune response through different functions, such as chemotaxis, phagocytosis, oxidative burst and degranulation, which have been widely studied. However, in the last few years, a new function has been described; activated neutrophils are able to release web-like chromatin structures known as neutrophil extracellular traps (NETs). These structures formed by DNA, histones, and proteins, immobilize and kill microorganisms. Disruption in NET formation is associated with the pathophysiology of several disorders, including the autoimmune diseases. NETs are an ...

IL-8 is a potent neutrophil chemoattractant that has been detected in high concentrations at acutely inflamed sites in vivo. Many cell types, including peripheral blood neutrophils, produce IL-8 that can be released by a variety of pro-inflammatory stimuli. However, the functional importance of neutrophil IL-8 during exudation is not yet known. We now report that neutrophils, harvested from skin lesions on the forearms of normal human volunteers (exudative neutrophils), expressed 100-fold higher levels of cell-associated IL-8 and spontaneously released up to 50-fold more IL-8 than freshly isolated peripheral blood neutrophils from the same donor. Furthermore, cell-associated IL-8 in peripheral blood neutrophils increased 20-fold during incubation at 37 degrees C in vitro and was increased over 200-fold after treatment with the Ca2+ ionophore A23187. More than 35% of the cell-associated IL-8 could be released by stimulation with either Ca2+ ionophore A23187 or phorbol myristate acetate. IL-8 was ...

Introduction: Hormonal and metabolic changes, as well as energy imbalance, can affect health, production and reproductive performance of dairy cows. In the present study, we evaluated phagocytosis and respiratory burst neutrophil activity during the transition period and early lactation and compared it with biochemical and hematological parameters in dairy cows. Methodology: Simmental cows (n = 21) were enrolled in the study. Whole blood samples were collected weekly from 3 weeks pre- calving until 6 weeks post calving. Basic metabolic and blood parameters were assessed by routine laboratory analyses, while neutrophil functions were analyzed by commercial test kits. Results: Optimal neutrophil response was observed pre and post calving. The highest value was recorded in the 6th week after calving (89.54 ± 7.61%) and being significantly higher (p , 0.01) as compared to values recorded at two and one week before and one week after calving. The percentage of activated neutrophils was high during ...

In a previous study we observed that neutrophils respond with a rapid rise in [Ca2+]i during adherence to cytokine-activated endothelial cells (EC), caused by EC membrane-associated platelet-activating factor (PAF). In the present study, we investigated whether this form of PAF was important in neutrophil adherence and migration across monolayers of rIL-1 beta- or rTNF alpha-prestimulated EC. PAF receptor antagonists prevented neutrophil migration across cytokine-pretreated EC by approximately 60% (P less than 0.005) without interfering with the process of adherence. The antagonists WEB 2086 and L-652,731 had no effect on neutrophil migration across resting EC induced by formylmethionyl-leucyl-phenylalanine (FMLP). A murine anti-IL-8 antiserum was found to also partially inhibit the neutrophil transmigration across cytokine-activated EC. When the anti-IL-8 antiserum was used in combination with a PAF receptor antagonist, neutrophil migration across cytokine-pretreated monolayers of EC was ...

Inhibition of LPS induced sputum neutrophil percentage. The reduction in sputum neutrophil percentage caused by active treatments compared to placebo are shown;

TY - JOUR. T1 - Nitrite generation and antioxidant effects during neutrophil apoptosis. AU - Misso, Neil L.A.. AU - Peacock, Craig D.. AU - Neil Watkins, D.. AU - Thompson, Philip J.. PY - 2000/3/15. Y1 - 2000/3/15. N2 - Neutrophil apoptosis is important for the resolution of airway inflammation in a number of lung diseases. Inflammatory mediators, endogenous reactive oxygen and nitrogen species, and intracellular and extracellular antioxidants may all influence neutrophil apoptosis. This study investigated the involvement of these factors during apoptosis of neutrophils cultured in vitro. Neutrophils undergoing spontaneous apoptosis in culture as assessed by annexin V binding generated significant amounts of nitrite. Incubation with agonistic anti-Fas monoclonal antibody or tumor necrosis factor-α (TNF-α) enhanced neutrophil apoptosis at 6 h, although it decreased nitrite accumulation. Although granulocyte-macrophage colony-stimulating factor significantly reduced neutrophil apoptosis, this ...

We introduce machine learning (ML) to perform classification and quantitation of images of nuclei from human blood neutrophils. Here we assessed the use of convolutional neural networks (CNNs) using free, open source software to accurately quantitate neutrophil NETosis, a recently discovered process involved in multiple human diseases. CNNs achieved ,94% in performance accuracy in differentiating NETotic from non-NETotic cells and vastly facilitated dose-response analysis and screening of the NETotic response in neutrophils from patients. Using only features learned from nuclear morphology, CNNs can distinguish between NETosis and necrosis and between distinct NETosis signaling pathways, making them a precise tool for NETosis detection. Furthermore, by using CNNs and tools to determine object dispersion, we uncovered differences in NETotic nuclei clustering between major NETosis pathways that is useful in understanding NETosis signaling events. Our study also shows that neutrophils from patients ...

Bacteria And Neutrophil Cell, Sem is a photograph by which was uploaded on May 10th, 2013. The photograph may be purchased as wall art, home decor, apparel, phone cases, greeting cards, and more. All products are produced on-demand and shipped worldwide within 2 - 3 business days.

This study shows that in mice selectively depleted of neutrophils by treatment with a monoclonal antibody, RB6-8C5, listeriosis is severely exacerbated in the liver, but not in the spleen or peritoneal cavity during the crucial first day of infection. At sites of infection in the livers of neutrophil-depleted mice, Listeria monocytogenes grew to large numbers inside hepatocytes. By contrast, in the livers of normal mice neutrophils rapidly accumulated at infectious foci and this was associated with the lysis of infected hepatocytes that served to abort infection in these permissive cells. In the spleen the situation was different, in that depletion of neutrophils did not result in appreciable exacerbation of infection. In this organ intact infected cells, many of which appeared to be fibroblast-like stromal cells, were found at foci of infection in the presence or absence of large numbers of neutrophils. This suggests that neutrophils are less effective at destroying L. monocytogenes-infected ...

Neutrophil extracellular traps (NETs) are networks of extracellular fibers, primarily composed of DNA from neutrophils, which bind pathogens. Neutrophils are the immune systems first-line of defense against infection and have conventionally been thought to kill invading pathogens through two strategies: engulfment of microbes and secretion of anti-microbials. In 2004, a novel third function was identified: formation of NETs. NETs allow neutrophils to kill extracellular pathogens while minimizing damage to the host cells. Upon in vitro activation with the pharmacological agent phorbol myristate acetate (PMA), Interleukin 8 (IL-8) or lipopolysaccharide (LPS), neutrophils release granule proteins and chromatin to form an extracellular fibril matrix known as NETs through an active process. High-resolution scanning electron microscopy has shown that NETs consist of stretches of DNA and globular protein domains with diameters of 15-17 nm and 25 nm, respectively. These aggregate into larger threads ...

Neutrophil granulocytes: Low neutrophil (neutropenia) and high neutrophil level counts on blood tests: Easy to understand entry on this type of white blood cell (Lymphocytes B cells and T cells; Monocytes; Eosinophils; Basophils).

Early and accurate risk assessment is an important clinical demand in patients with infective endocarditis (IE). The neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) are independent predictors of prognosis in many infectious and cardiovascular diseases. Very limited studies have been conducted to evaluate the prognostic role of these markers in IE. We analyzed clinical, laboratory, and echocardiographic data and outcomes throughout the whole period of hospitalization for a total of 142 consecutive patients with definitive IE. The overall in-hospital mortality was 21%. Major complications defined as central nervous system embolization, fulminant sepsis, acute heart failure, acute renal failure, and major artery embolization occurred in 38 (27%), 34 (24%), 32 (22.5%), 40 (28%), and 90 (63.4%) patients, respectively. The NLR, total leucocyte count (TLC), neutrophil percentage, creatinine, and C-reactive protein (CRP) level obtained upon admission were significantly higher in the

TY - JOUR. T1 - Endotoxin-induced selective dysfunction of rabbit polymorphonuclear leukocytes in response to endogenous chemotactic factors. AU - Hartiala, K. T.. AU - Langlois, L.. AU - Goldstein, I. M.. AU - Rosenbaum, J. T.. PY - 1985. Y1 - 1985. N2 - To assess the mechanism and specificity of polymorphonuclear leukocytes (PMN) dysfunction induced by endotoxin, rabbits were injected intravenously with 100 μg of Escherichia coli endotoxin, and PMN function was studied 18 to 24 h later. Compared to PMN from normal rabbits, peripheral blood PMN from rabbits injected with endotoxin showed diminished chemotactic responsiveness to two endogenous peptides, C5a (complement) and platelet-derived growth factor, and to two endogenous lipids, leukotriene B4 and platelet-activating factor. The chemotactic response to the synthetic chemotactic peptide, N-formyl-methionyl-leucyl-phenylalanine (FMLP), was unimpaired. In contrast to migration, endotoxin injection resulted in inhibition of the secretory ...

TY - JOUR. T1 - Rac2 concentrations in umbilical cord neutrophils. AU - Meade, Virginia M.. AU - Barese, Cecilia N.. AU - Kim, Chaekyun. AU - Njinimbam, Charles G.. AU - Marchal, Christophe C.. AU - Ingram, David A.. AU - Clapp, D. Wade. AU - Dinauer, Mary C.. AU - Yoder, Mervin C.. PY - 2006/9/1. Y1 - 2006/9/1. N2 - Background: Human newborn infants display a variety of immunodeficiencies of immaturity, including diminished neutrophil adhesion, chemotaxis, and migration. Rac2, a guanosine triphosphate-binding protein, is an essential regulator of human neutrophil migration and chemotaxis. Since human subjects and mice deficient in Rac2 display deficiencies in neutrophil functions similar to newborn infants, we postulated that newborn neutrophils may be deficient in Rac2. Objectives: The aim of the study was to measure Rac1 and Rac2 concentrations in neutrophils from umbilical cord blood. Methods: Neutrophils from cord and adult blood were isolated, total cell lysates extracted, and Rac protein ...

Depletion of neutrophils following sand fly bite enhances the efficacy of ALM+CpG vaccination.AMC, ALM+CpG vaccinated, or healed mice were exposed to the bites

Cystic fibrosis (CF) lung disease is defined by large numbers of neutrophils and associated damaging products in the airway. Delayed neutrophil apoptosis is described in CF although it is unclear whether this is a primary neutrophil defect or a response to chronic inflammation. Increased levels of neutrophil extracellular traps (NETs) have been measured in CF and we aimed to investigate the causal relationship between these phenomena and their potential to serve as a driver of inflammation. We hypothesised that the delay in apoptosis in CF is a primary defect and preferentially allows CF neutrophils to form NETs, contributing to inflammation ...

In this study, we demonstrated that a modest reduction of neutrophil counts in patients with T1D at onset is accompanied by a marked elevation of protein levels and enzymatic activities of NE and PR3, the two major neutrophil serine proteases. Furthermore, these changes in T1D patients are closely associated with increased neutrophil NETosis, as determined by quantification of MPO-DNA complexes in the circulation. These findings suggest that the reduction of neutrophil counts in T1D patients is partly attributed to augmented NETosis, which in turn leads to increased NET formation and the release of NE and PR3 into the blood stream.. We showed that the amplitude of elevation in circulating NE/PR3 enzymatic activities and NET formation in patients with disease duration of ,1 year is substantially higher than those with disease duration of ,1 year. A significant reduction in neutrophil counts is observed only in T1D patients with a disease duration of ,1 year. Consistent with our findings, a ...

Emerging evidence shows that miRNAs are substantially involved in myelopoiesis, but the role of miRNAs in the development of neutrophils remains elusive. In this study, we provided genetic evidence that miR-142-3p plays an essential role in the regulation of neutrophil homeostasis and maturation. Up to this point, the best-known miRNA that regulates neutrophil development is miR-223. A previous study in knockout mouse has revealed that miR-223 acts as a negative regulator of progenitor proliferation and granulocyte differentiation.7 As revealed by that study, miR-223-deficient neutrophils exhibit an unusual hypermature morphology that is characterized by nuclear hypersegmentation and blebbing, which is reminiscent of the granulocytes observed in human myelokathexis,44 and those abnormalities of neutrophils were also observed in our miR-142ab−/− knockout zebrafish. Moreover, a previous study showed that miR-142 is positively regulated by miR-223 in the myeloid cell line K562. Considering the ...

To determine if the SHIP phosphatase activity is sufficient to alter neutrophil motility, we ectopically expressed a membrane-bound form of the human SHIP1 phosphatase domain (aa364-826) in zebrafish neutrophils (Freeburn et al., 2002). Transient expression was achieved using the lyz promoter driving both the constitutively active SHIP1 phosphatase and EGFP expression with the viral 2A peptide system which allows multiple protein products to be expressed from a single transgene (Provost et al., 2007). Transient expression of this construct in Tg(mpx:mCherry) embryos allowed for mosaic expression of the phosphatase domain labeled with EGFP and mCherry to be compared to control neutrophils that expressed mCherry alone. Live imaging of neutrophil random motility in the head of 3 dpf embryos showed that ectopic expression of the SHIP1 phosphatase domain impaired neutrophil random motility as compared to control neutrophils (Fig. 4D-E; supplementary material Movie 7). By contrast, ectopic expression ...

Neutrophils (also called polymorphonuclear leukocytes, PMNs) are the most abundant white blood cells in humans and play a central role in innate host defense. Another distinguishing feature of PMNs is their short lifespan. Specifically, these cells survive for less than 24 hours in the bloodstream and are inherently pre-programed to die by constitutive apoptosis. Recent data indicate that this process is regulated by intracellular signaling and changes in gene expression that define an apoptosis differentiation program. Infection typically accelerates neutrophil turnover, and as such, phagocytosis-induced cell death (PICD) and subsequent clearance of the corpses by macrophages are essential for control of infection and resolution of the inflammatory response. Herein we reprise recent advances in our understanding of the molecular mechanisms of neutrophil apoptosis with a focus on regulatory factors and pathway intermediates that are specific to this cell type. In addition, we summarize mechanisms

Following inhibition of DPP1 in the rat, the NSP activity was determined by the amount of DPP1 inhibition and the turnover of neutrophils and is thus supportive of the role of neutrophil maturation in the activation of NSPs. Clinical trials to monitor the effect of a DPP1 inhibitor on NSPs should ta …

BioAssay record AID 101434 submitted by ChEMBL: Inhibition of leukotriene B4 (LTB4) binding to its receptor on intact human neutrophils.

Cystic fibrosis (CF) is an autosomal recessive disorder caused by mutations in the gene that codes for the CF trans-membrane conductance regulator. These mutations result in abnormal secretions viscous airways of the lungs, favoring pulmonary infection and inflammation in the middle of neutrophil recruitment. Recently it was described that neutrophils can contribute with disease pathology by extruding large amounts of nuclear material through a mechanism of cell death known as Neutrophil Extracellular Traps (NETs) into the airways of patients with CF. Additionally, NETs production can contribute to airway colonization with bacteria, since they are the microorganisms most frequently found in these patients. In this review, we will discuss the implication of individual or mixed bacterial infections that most often colonize the lung of patients with CF, and the NETs role on the disease.

TY - JOUR. T1 - Acute inflammatory reaction after myocardial ischemic injury and reperfusion. Development and use of a neutrophil-specific antibody. AU - Hawkins, Hal K.. AU - Entman, Mark L.. AU - Zhu, Jessica Y.. AU - Youker, Keith A.. AU - Berens, Kurt. AU - Doré, Monique. AU - Smith, C. Wayne. PY - 1996/6. Y1 - 1996/6. N2 - Reperfusion of the infarcted canine myocardium after 1 hour of ischemia is associated with an acute inflammatory infiltrate at the border of the infarct. In this paper, we demonstrate that early margination and emigration of neutrophils originate in thin-walled (∼5-μm) venous cisterns that average 200 μm in length and vary from 10 to 70 μm in width and show strong constitutive expression of both ICAM-1 and P-selectin; this class of vessels (venous cisterns) appears to be a unique feature in heart. A monoclonal antibody (SG8H6) with specificity for canine neutrophils was developed that allowed much more sensitive immunohistochemical detection of neutrophils in tissue ...

Neutrophil swarming is a specific type of neutrophil migration behaviour characterised by a high coordination between neutrophils, clustering of neutrophils to the inflammation site and signalling to other neutrophils further away. This specific type of migration rely on the production and secretion of LTB4 and on the use of integrins for neutrophil to stop at the cluster site. Tan, Sioh-Yang; Weninger, Wolfgang (February 2017). Neutrophil migration in inflammation: intercellular signal relay and crosstalk. Current Opinion in Immunology. 44: 34-42. doi:10.1016/j.coi.2016.11.002. L?mmermann, Tim; Afonso, Philippe V.; Angermann, Bastian R.; Wang, Ji Ming; Kastenm?ller, Wolfgang; Parent, Carole A.; Germain, Ronald N. (26 May 2013). Neutrophil swarms require LTB4 and integrins at sites of cell death in vivo. Nature. 498 (7454): 371-375. doi:10.1038/nature12175 ...

TY - JOUR. T1 - Endogenous nitric oxide inhibits neutrophil adherence to lung epithelial cells to modulate interleukin-8 release. AU - Lin, Horng Chyuan. AU - Wang, Chun Hua. AU - Yu, Chih Teng. AU - Hwang, Kuo Shiung. AU - Kuo, Han Pin. PY - 2001/8/3. Y1 - 2001/8/3. N2 - To investigate the effect of neutrophil adherence to epithelial cells on the release of interleukin 8 (IL-8), we measured neutrophil adherence in the presence or absence of IFN-γ+TNF-α+IL-1β (cytomix) stimulation on cultured A549 epithelial cells. The extent of neutrophil adherence to A549 epithelial cells was measured and the concomitant production of IL-8 and nitrite were assayed. The roles of adhesion molecules and nitrite in modulation of neutrophil adherence were examined by pretreatment with oversaturating ICAM-1 blocking antibody and L-NAME (1mM), respectively. There was a time-dependent spontaneous and cytomix-induced release of IL-8 from epithelial cells, as well as a time-dependent increase in the magnitude of ...

TY - CHAP. T1 - Neutrophil isolation from nonhuman species. AU - Siemsen, Daniel W.. AU - Malachowa, Natalia. AU - Schepetkin, Igor A.. AU - Whitney, Adeline R.. AU - Kirpotina, Liliya N.. AU - Lei, Benfang. AU - Deleo, Frank R.. AU - Quinn, Mark T.. PY - 2014. Y1 - 2014. N2 - The development of new advances in the understanding of neutrophil biochemistry requires effective procedures for isolating purified neutrophil populations. Although methods for human neutrophil isolation are now standard, similar procedures for isolating neutrophils from many of the nonhuman species used to model human diseases are not as well developed. Since neutrophils are reactive cells, the method of isolation is extremely important to avoid isolation technique-induced alterations in cell function. We present methods here for reproducibly isolating highly purified neutrophils from large animals (bovine, equine, ovine), small animals (murine and rabbit), and nonhuman primates (cynomolgus macaques), and describe ...

Neutrophil invasion of inflamed tissue is a complex process involving an initial mild adhesive interaction with the venular endothelium, termed rolling, which allows neutrophils to remain in close apposition to the endothelial cells and to sample the environment for local signals of an ongoing inflammatory process.1 2 3 If the appropriate signals (stimuli) are present, the neutrophils become activated, and a strong adhesive interaction takes place. This results in neutrophil arrest and eventual emigration toward the chemotactic stimulus in the interstitium. Although there is a general consensus on the mechanisms (adhesion molecule activation/expression) involved in neutrophil-endothelial cell adhesive interactions,1 2 3 the mechanisms by which neutrophils penetrate the endothelial cell lining to gain access to the interstitium remain controversial. The barriers to neutrophil movement to the site of chemotactic (or inflammatory) stimuli in the interstitium are (1) the endothelial cells lining the ...

Background: The inflamed bronchial mucosal surface is a profoundly hypoxic environment. Neutrophilic airway inflammation and neutrophil-derived proteases have been linked to disease progression in conditions such as COPD and cystic fibrosis, but the effects of hypoxia on potentially harmful neutrophil functional responses such as degranulation are unknown. Methods and results: Following exposure to hypoxia (0.8% oxygen, 3 kPa for 4 h), neutrophils stimulated with inflammatory agonists (granulocyte-macrophage colony stimulating factor or platelet-activating factor and formylated peptide) displayed a markedly augmented (twofold to sixfold) release of azurophilic (neutrophil elastase, myeloperoxidase), specific (lactoferrin) and gelatinase (matrix metalloproteinase-9) granule contents. Neutrophil supernatants derived under hypoxic but not normoxic conditions induced extensive airway epithelial cell detachment and death, which was prevented by coincubation with the antiprotease α-1 antitrypsin; ...

In contrast to other isolation techniques, neutrophils enriched by spontaneous sedimentation were found to be intact both in terms of their function and relative numbers within the

Although resistin was recently found to modulate insulin resistance in preclinical models of type II diabetes and obesity, recent studies also suggested that resistin has proinflammatory properties. We examined whether the human-specific variant of resistin affects neutrophil activation and the severity of LPS-induced acute lung injury. Because human and mouse resistin have distinct patterns of tissue distribution, experiments were performed using humanized resistin mice that exclusively express human resistin (hRTN +/-/-) but are deficient in mouse resistin. Enhanced production of TNF-α or MIP-2 was found in LPS-treated hRtn+/-/- neutrophils compared with control Rtn-/-/- neutrophils. Expression of human resistin inhibited the activation of AMPactivated protein kinase, a major sensor and regulator of cellular bioenergetics that also is implicated in inhibiting inflammatory activity of neutrophils and macrophages. In addition to the ability of resistin to sensitize neutrophils to LPS ...

Looking for online definition of neutrophil microbicidal assay in the Medical Dictionary? neutrophil microbicidal assay explanation free. What is neutrophil microbicidal assay? Meaning of neutrophil microbicidal assay medical term. What does neutrophil microbicidal assay mean?

Are neutrophil/lymphocyte ratio and platelet/lymphocyte ratio reliable parameters as prognostic indicators in malignant mesothelioma? Seda Tural Onur,1 Sinem Nedime Sokucu,1 Levent Dalar,2 Sinem Iliaz,1 Kaan Kara,1 Songül Buyukkale,3 Sedat Altin1 1Department of Chest Diseases, Yedikule Chest Diseases and Thoracic Surgery Training and Research Hospital, 2Department of Pulmonary Medicine, Faculty of Medicine, Istanbul Bilim University, 3Department of Thoracic Surgery, Yedikule Chest Diseases and Thoracic Surgery Training and Research Hospital, Istanbul, Turkey Background: Malignant mesothelioma (MM) is an aggressive asbestos-related pleural tumor. The incidence is increasing with intensive use of asbestos in developing countries. We need an easily accessible, inexpensive, and reliable method for determining the low survival time prognosis of this tumor. The aim of our study was to investigate the viability of neutrophil/lymphocyte ratio (NLR) and platelet/lymphocyte ratio (PLR) as prognostic

Results In vehicle treated neutrophils, there was increased viability and less apoptosis in bronchiectasis patients compared to healthy volunteers; Figure 1. There was a significant increase in CD11b upregulation; p = 0.01 and CD62L shedding; p = 0.01 in bronchiectasis patients compared to healthy volunteers. There was a significant increase in neutrophil degranulation with myeloperoxidase (MPO) release, in bronchiectasis patients; p = 0.04. There was an increase in neutrophil phagocytosis of GFP labelled Pseudomonas aeruginosa by neutrophils from bronchiectasis patients, p = 0.03, compared to healthy volunteers; Figure1.. In LXA4 treated neutrophils, there was no effect of LXA4 on spontaneous neutrophil apoptosis. There was a significant reduction in n-formyl-methyl-leucyl-phenylalanine (fMLF)-induced CD11b upregulation and CD62L shedding by LXA4 in a dose dependent manner in all three groups. There was a significant reduction in cytochalasin-B and fMLF-induced activation of neutrophils and ...

Serine proteinases of human polymorphonuclear neutrophils play an important role in neutrophil-mediated proteolytic events; however, the non-oxidative mechanisms by which the cells can degrade extracellular matrix in the presence of proteinase inhibitors have not been elucidated. Herein, we provide the first report that human neutrophils express persistently active cell surface-bound human leukocyte elastase and cathepsin G on their cell surface. Unstimulated neutrophils have minimal cell surface expression of these enzymes; however, phorbol ester induces a 30-fold increase. While exposure of neutrophils to chemoattractants (fMLP and C5a) stimulates modest (two- to threefold) increases in cell surface expression of serine proteinases, priming with concentrations of lipopolysaccharide as low as 100 fg/ml leads to striking (up to 10-fold) increase in chemoattractant-induced cell surface expression, even in the presence of serum proteins. LPS-primed and fMLP-stimulated neutrophils have ...

Helicobacter pylori (HP) can cause many diseases and malignant conditions. In the stomach, HP causes mucosal injury and inflammation. We determined the association of the platelet/lymphocyte ratio (PLR) and neutrophil/lymphocyte ratio (NLR) with HP-positive and HP-negative gastritis severity. We retrospectively reviewed 234 patients who had undergone upper gastrointestinal endoscopy for the investigation of dyspepsia and reflux symptoms. The patients were divided into three groups according to the results of the histopathologic evaluation: HP-negative gastritis group, HP-positive gastritis group and control group (neither HP positivity nor gastritis). We routinely collected laboratory data, including complete blood count, from all the patients. The mean neutrophil count was higher and the mean lymphocyte count was lower in the HP-positive gastritis group than in the other groups. The mean platelet count was increased in all groups, but the lowest increase was seen in the HP-positive gastritis ...

Neutrophils release neutrophil extracellular traps (NETs) which ensnare pathogens and have pathogenic functions in diverse diseases. We examined the NETosis pathways induced by five stimuli; PMA, the calcium ionophore A23187, nigericin, Candida albicans and Group B Streptococcus. We studied NET production in neutrophils from healthy donors with inhibitors of molecules crucial to PMA induced NETs including protein kinase C, calcium, reactive oxygen species, the enzymes myeloperoxidase (MPO) and neutrophil elastase. Additionally, neutrophils from chronic granulomatous disease patients, carrying mutations in the NADPH oxidase complex or a MPO-deficient patient were examined. We show that PMA, C. albicans and GBS use a related pathway for NET induction whereas ionophores require an alternative pathway but that NETs produced by all stimuli are proteolytically active, kill bacteria and composed mainly of chromosomal DNA. Thus, we demonstrate that NETosis occurs through several signalling mechanisms,

The Predictive Value of Total Neutrophil Count and Neutrophil/ Lymphocyte Ratio in Predicting In-hospital Mortality and Complications after STEMI ...

A wide variety of microbial and inflammatory factors induce DNA release from neutrophils as neutrophil extracellular traps (NETs). Consensus on the kinetics and mechanism of NET release has been hindered by the lack of distinctive methods to specifically quantify NET release in time. Here, we validate and refine a semi-automatic ... read more live imaging approach for quantification of NET release. Importantly, our approach is able to correct for neutrophil input and distinguishes NET release from neutrophil death by other means, aspects that are lacking in many NET quantification methods. Real time visualization shows that opsonized S. aureus rapidly induces cell death by toxins, while actual NET formation occurs after 90 minutes, similar to the kinetics of NET release by immune complexes and PMA. Inhibition of SYK, PI3K and mTORC2 attenuates NET release upon challenge with physiological stimuli but not with PMA. In contrast, neutrophils from chronic granulomatous disease patients show ...

Alpha-1 antitrypsin (AAT) deficiency (AATD) is characterised by excessive neutrophil degranulation and a protease: anti-protease imbalance leading to premature emphysema. Current specialised treatment for AATD consists of once weekly infusion of plasma purified AAT. Neutrophil degranulation is under the control of small GTP-binding proteins, including Ras-related C3 botulinum toxin substrate 2 (Rac2). The molecular basis for aberrant neutrophil degranulation in AATD has not been elucidated to date. The aim of this study was to fully characterise neutrophil degranulation in AATD and to determine the effects of AAT augmentation therapy on the AATD neutrophil. In this study, we examined degranulation by AATD neutrophils by Western blotting. This revealed a 3-fold increase in levels of myeloperoxidase (MPO), human cathelicidin antimicrobial protein (hCAP-18) and matrix metalloprotease-9 (MMP-9), markers of primary, secondary and tertiary granules, respectively (p=0.023, p=0.036 and p=0.042, respectively).

|jats:title|Abstract|/jats:title| |jats:sec| |jats:title|Background|/jats:title| |jats:p|Neutrophil activation results in Plasmodium parasite killing in vitro, but neutrophil products including neutrophil extracellular traps (NETs) mediate host organ damage and may contribute to severe malaria. The role of NETs in the pathogenesis of severe malaria has not been examined.|/jats:p| |/jats:sec| |jats:sec| |jats:title|Methods|/jats:title| |jats:p|In Papua, Indonesia, we enrolled adults with symptomatic Plasmodium falciparum (n = 47 uncomplicated, n = 8 severe), Plasmodium vivax (n = 37), or Plasmodium malariae (n = 14) malaria; asymptomatic P falciparum (n = 19) or P vivax (n = 21) parasitemia; and healthy adults (n = 23) without parasitemia. Neutrophil activation and NETs were quantified by immunoassays and microscopy and correlated with parasite biomass and disease severity.|/jats:p|

The production of reactive oxygen metabolites by neutrophils is thought to play a key role in host defense against invading microorganisms. In this study, the generation of oxygen metabolites induced by two uropathogenic Escherichia coli strains, ABU2 and PN7, and their subsequent killing in neutrophils were investigated. Both strains were grown to promote type 1 (mannose-sensitive) fimbria formation, but they differ with respect to other surface structures. When interacting with human neutrophils, the ABU2 bacteria adhered to and were phagocytized by the neutrophils, whereas PN7 bacteria adhered to the neutrophils but resisted phagocytosis. Both strains induced a pronounced neutrophil chemiluminescence response. However, when the intracellular and extracellular parts of the oxidative response were separated, we found that the predominant part of the response was of intracellular origin with the ABU2 bacteria as prey, whereas a large fraction of the response induced by the PN7 bacteria was ...

TY - JOUR. T1 - Source of iron in neutrophil-mediated killing of endothelial cells. AU - Gannon, D. E.. AU - Varani, J.. AU - Phan, S. H.. AU - Ward, J. H.. AU - Kaplan, J.. AU - Till, G. O.. AU - Simon, R. H.. AU - Ryan, U. S.. AU - Ward, P. A.. PY - 1987/9/10. Y1 - 1987/9/10. N2 - Recently we have shown that human neutrophils activated with phorbol ester are cytotoxic for cultured boving pulmonary artery endothelial cells in an iron-dependent manner. By using the ferric iron chelator deferoxamine mesylate, we have now investigated the source of the iron. Pretreatment of neutrophils with deferoxamine mesylate affected neither their production of O2- nor their cytotoxicity for endothelial cells after addition of phorbol ester. However, similar pretreatment of endothelial cells with deferoxamine mesylate, followed by washing of the cells, resulted in a persistent presence of chelator associated with the endothelial cells and high degrees of protection of endothelial cells from cytotoxicity. The ...

Both cis and trans unsaturated fatty acids and sodium dodecyl sulfate activated NADPH oxidase in plasma membranes of human neutrophils in the presence of neutrophil cytosol. In contrast, 5,8,11,14-icosatetraynoic acid, saturated fatty acids, esters, peroxides and 4 beta-phorbol 12-myristate 13-acetate, a potent activator of protein kinase C, were inactive. 5,8,11,14-icosatetraynoic acid inhibited superoxide formation elicited by fatty acids. Guanosine 5[gamma-thio]triphosphate (GTP[gamma S]), a potent activator of guanine-nucleotide-binding proteins (N-proteins) enhanced superoxide formation elicited by fatty acids up to fourfold, supporting our previous suggestion that NADPH oxidase is regulated by an N-protein [Seifert, R. et al. (1986) FEBS Lett. 205, 161-165]. Cytosols from various tissues, soybean lipoxygenase and protein kinase C, purified from chicken stomach, did not substitute neutrophil cytosol. The activity of neutrophil cytosol was destroyed by heating at 95 degrees C. Superoxide ...

Background: There is a direct relation between C-reactive protein and leukocyte count as indicators of inflammation. The neutrophil lymphocyte ratio (NLR) is the balance between both cells and is considered a marker of low-grade inflammation and an indicator of high risk of cardiovascular events. An elevated NLR is related with type 2 diabetes (T2D), however, even when in type 1 diabetes (T1D) there is an underlying inflammatory process, an elevation of circulating neutrophils isn t observed. NLR is associated with hyperglycemia in adult patients with long-duration T2D. However, reports in pediatric populations with recent-onset type 1 (T1D) and T2D are scarce.. Objective and hypotheses: To evaluate the association between NLR and the degree of glycemic control in pediatric patients with recent-onset T1D and T2D vs healthy controls.. Method: Design: Analytical cross-sectional. Subjects 8 16 years of age were included, with T1D or T2D with diagnosis ≤ 3 months, who, with their guardians, signed ...

Here we investigated microtubule dynamics and function during neutrophil migration in vivo. In accordance with reported in vitro findings, we found that microtubule disruption impairs neutrophil directed migration to wounds but induces cell motility and polarity in a PI(3)K-independent manner. We also found that Rho mediates nocodazole-induced neutrophil motility. These findings are consistent with previous findings in vitro, but further provide a physiological context for neutrophil migration. In addition, we elucidated two previously unidentified roles of microtubules during neutrophil motility in vivo. First, microtubule arrays nucleate in front of the nucleus and mainly radiate towards the uropod. Second, Rac is activated by microtubule depolymerization in primary human neutrophils and is necessary for nocodazole-induced neutrophil motility in vivo.. Leukocytes are often described as having the microtubule cytoskeleton and MTOC behind the nucleus at the uropod (Friedl and Weigelin, 2008; ...

We have previously shown that gadolinium oxide (Gd2O3) nanoparticles are promising candidates to be used as contrast agents in magnetic resonance (MR) imaging applications. In this study, these nanoparticles were investigated in a cellular system, as possible probes for visualization and targeting intended for bioimaging applications. We evaluated the impact of the presence of Gd2O3 nanoparticles on the production of reactive oxygen species (ROS) from human neutrophils, by means of luminol-dependent chemiluminescence. Three sets of Gd2O3 nanoparticles were studied, i.e. as synthesized, dialyzed and both PEG-functionalized and dialyzed Gd2O3 nanoparticles. In addition, neutrophil morphology was evaluated by fluorescent staining of the actin cytoskeleton and fluorescence microscopy. We show that surface modification of these nanoparticles with polyethylene glycol (PEG) is essential in order to increase their biocompatibility. We observed that the as synthesized nanoparticles markedly decreased the ...

Neutrophils play a critical role in host defense against invading pathogens. Chemotaxis, the directed migration of cells, allows neutrophil to seek out the sites of inflammation and infection. Neutrophil chemotaxis as well as other type of cell migration are considered as cycles composed of highly orchestrated steps. Recently the underlying signaling mechanisms of neutrophil chemotaxis are better understood with the studies in knockout mice and neutrophil-like cell lines: a number of signaling molecules in neutrophil chemotaxis have been identified, and a feedback loop-based model of frontness and backness pathways has been proposed to explain the establishment of neutrophil polarity and chemotaxis. However, the signaling mechanisms that control actin cytoskeleton reorganization and interaction between the cells and the substratum on which cells migrate are still not fully understood. In my first research project, we have identified a signaling pathway, mediated by non-receptor tyrosine ...

TY - JOUR. T1 - Neutrophil Extracellular Traps Enhance Staphylococcus Aureus Vegetation Formation through Interaction with Platelets in Infective Endocarditis. AU - Hsu, Chih-Chieh. AU - Hsu, Ron-Bin. AU - Ohniwa, Ryosuke L. AU - Chen, Jeng-Wei. AU - Yuan, Chang-Tsu. AU - Chia, Jean-San. AU - Jung, Chiau-Jing. N1 - Georg Thieme Verlag KG Stuttgart · New York.. PY - 2019/5. Y1 - 2019/5. N2 - The mechanisms or host factors involved in septic thrombus or vegetation formation in Staphylococcus aureus-induced infective endocarditis (IE) are unclear. Using an experimental endocarditis rat model, here we demonstrated that S. aureus HG001-induced vegetation was composed of bacterial floes encased in aggregated platelets and surrounded by neutrophil extracellular traps (NETs). In vitro data demonstrated that platelets contribute to both biofilm and NET formation. Prophylactic administration of DNase I significantly reduced the size of vegetation induced by methicillin-resistant S. aureus (MRSA) and ...

Introduction Neutrophils accumulate in the lungs of patients with bronchiectasis and cystic fibrosis, and the resulting inflammation causes tissue hypoxia. Neutrophils have a unique ability to survive and function in such hypoxic environments, a response regulated by the hypoxia-inducible transcription factor (HIF)/hydroxylase oxygen sensing pathway.. Pseudomonas aeruginosa is an opportunistic pathogen which colonises patients with chronic lung disease, including cystic fibrosis. It secretes the toxin pyocyanin, which induces neutrophil apoptosis in an oxygen-dependent manner, as a means of immune-evasion. P. aeruginosa has recently been shown to possess hydroxylase-homologs, suggesting that prokaryotes may also have oxygen-sensing capabilities. A prolyl-hydroxylase (PHD)-deficient strain secretes higher levels of pyocyanin compared with wild-types.. We hypothesised that PHD-deficient P. aeruginosa induces a higher degree of neutrophil death compared with an otherwise genetically identical ...

Synergistic regulation of endogenous TRPM2 channels by adenine dinucleotides in primary human neutrophils. Cell Calcium.2008 Dec;44(6):604-15; Epub 2008 Jun 24; PubMed Central PMCID: PMC2597220.PMED ID: 18572241. ...

article{f7336ebb-e740-4acd-bf1a-ccf3f3a2c8e1, author = {Weineisen, Maria and Sjöbring, Ulf and Fällman, Maria and Andersson, Tommy}, issn = {1550-6606}, language = {eng}, number = {6}, pages = {3798--3807}, publisher = {American Association of Immunologists}, series = {Journal of Immunology}, title = {Streptococcal M5 protein prevents neutrophil phagocytosis by interfering with CD11b/CD18 receptor-mediated association and signaling.}, volume = {172}, year = {2004 ...

COVID-19 affects millions of patients worldwide with clinical presentation ranging from isolated thrombosis to acute respiratory distress syndrome (ARDS) requiring ventilator support. Neutrophil extracellular traps (NETs) originate from decondensed chromatin released to immobilize pathogens and can trigger immunothrombosis. We studied the connection between NETs and COVID-19 severity and progression. We conducted a prospective cohort study of COVID-19 patients (n=33) with age- and sex-matched controls (n=17). We measured plasma myeloperoxidase (MPO)-DNA complexes (NETs), Platelet Factor 4, RANTES, and selected cytokines. Three COVID-19 lung autopsies were examined for NETs and platelet involvement. We assessed NET formation ex vivo in COVID-19 neutrophils and in healthy neutrophils incubated with COVID-19 plasma. We also tested the ability of neonatal NET-Inhibitory Factor (nNIF) to block NET formation induced by COVID-19 plasma. Plasma MPO-DNA complexes increased in COVID-19 with intubation ...

Neutrophil granulocytes constitute the front line of defense in the innate immune response to invading microorganisms, but can also contribute to development of inflammatory disease and tissue destruction following e.g. myocardial infarction or stroke. During inflammatory activation, neutrophils leave the blood, interact with extracellular matrix proteins, and migrate into tissues in response to chemotactic factors to phagocytose and kill infectious agents by using toxic granule contents and reactive oxygen metabolites. The functional neutrophil response relies on exocytosis of cytoplasmic granules, each containing membrane proteins, which are thereby mobilized to the plasma membrane. Specific programmed cell death (apoptotic) pathways regulate neutrophil homeostasis, where an inflammatory milieu can prolong the life span of neutrophils to several days, whereas non-activated neutrophils are committed to constitutive/spontaneous apoptosis within hours.. Signal regulatory protein alpha (SIRPα) is ...

Activated neutrophils release proteases that function in neutrophil extracellular traps to mediate bacterial killing and that also function as autocrine regulators of neutrophil function. Previous work had shown that neutrophils deficient in two proteases, cathepsin G and elastase (CG/NE), did not respond to activation by immune complexes in vitro and that the response was restored by exogenous addition of cathepsin G. Woloszynek et al. performed a proteomic proteolysis screen of CG/NE-deficient neutrophils stimulated with immune complexes and then treated with cathepsin G and identified four candidate targets of cathepsin G. Of these, Annexin A1 (AnxA1) and CRAMP (the mouse ortholog of human cathelicidin) had been previously reported as substrates of serine proteases that modulate neutrophil function, and those were selected for further evaluation. Both AnxA1 and CRAMP were substrates of cathepsin G in vitro, with AnxA1 cleaved to the active product and CRAMP only partially cleaved. Comparison ...

Neutrophil extracellular traps (NETs) have been implicated in the pathogenesis of systemic Lupus erythematosus (SLE), since netting neutrophils release potentially immunogenic autoantigens including histones, LL37, human neutrophil peptide (HNP), and self-DNA. In turn, these NETs activate plasmacytoid dendritic cells resulting in aggravation of inflammation and disease. How suppression of NET formation can be targeted for treatment has not been reported yet. Signal Inhibitory Receptor on Leukocytes-1 (SIRL-1) is a surface molecule exclusively expressed on phagocytes. We recently identified SIRL-1 as a negative regulator of human neutrophil function. Here, we determine whether ligation of SIRL-1 prevents the pathogenic release of NETs in SLE. Peripheral blood neutrophils from SLE patients with mild to moderate disease activity and healthy donors were freshly isolated. NET release was assessed spontaneously or after exposure to anti-neutrophil antibodies or plasma obtained from SLE patients. The ...

TY - JOUR. T1 - Conditioned medium from stimulated mononuclear leucocytes potentiates the ability of human neutrophils do damage human articular cartilage. AU - Bates, E. J.. AU - Kowanko, I. C.. AU - Ferrante, A.. N1 - Copyright: Copyright 2017 Elsevier B.V., All rights reserved.. PY - 1988. Y1 - 1988. N2 - Human neutrophils were able to degrade proteoglycan and inhibit its synthesis when incubated with human articular cartilage coated with heat aggregated immunoglobulin G. These effects were potentiated when culture medium conditioned by mononuclear leucocytes stimulated with killed Staphylococcus aureus was also present during the incubations. Neutrophils preincubated with this conditioned medium and washed before incubation with cartilage also showed an increased ability to degrade proteoglycan and inhibit its synthesis. The percentage of neutrophils binding to cartilage was significantly increased in the presence of this conditioned medium.. AB - Human neutrophils were able to degrade ...

The coronavirus disease 2019 (COVID-19) has become a pandemic. Rapidly distinguishing COVID-19 from other respiratory infections is a challenge for first-line health care providers. This retrospective study was conducted at the Taipei Medical University Hospital, Taiwan. Patients who visited the outdoor epidemic prevention screening station for respiratory infection from February 19 to April 30, 2020, were evaluated for blood biomarkers to distinguish COVID-19 from other respiratory infections. Monocyte distribution width (MDW) ≥ 20 (odds ratio [OR]: 8.39, p = 0.0110, area under curve [AUC]: 0.703) and neutrophil-to-lymphocyte ratio (NLR) | 3.2 (OR: 4.23, p = 0.0494, AUC: 0.673) could independently distinguish COVID-19 from common upper respiratory tract infections (URIs). Combining MDW ≥ 20 and NLR | 3.2 was more efficient in identifying COVID-19 (AUC: 0.840). Moreover, MDW ≥ 20 and NLR | 5 effectively identified influenza infection (AUC: 0.7055). Thus, MDW and NLR can distinguish COVID-19 from

We have developed induced pluripotent stem cells (iPSCs) from a patient with X-linked chronic granulomatous disease (X-CGD), a defect of neutrophil microbicidal reactive oxygen species (ROS) generation resulting from gp91phox deficiency. We demonstrated that mature neutrophils differentiated from X-CGD iPSCs lack ROS production, reproducing the pathognomonic CGD cellular phenotype. Targeted gene transfer into iPSCs, with subsequent selection and full characterization to assure no off-target changes, holds promise for correction of monogenic diseases without the insertional mutagenesis caused by multisite integration of viral or plasmid vectors. Zinc finger nuclease mediated gene targeting of a single copy gp91phox therapeutic minigene into one allele of the safe harbor AAVS1 locus in X-CGD iPSCs without off-target inserts resulted in sustained expression of gp91phox and substantially restored neutrophil ROS production. Our findings demonstrate how precise gene targeting may be applied to ...

Neutrophil-To-Lymphocyte Ratio (NLR) Platelet-To-Lymphocyte Ratio (PLR), and Outcomes With Nivolumab in Pretreated Non-Small Cell Lung Cancer (NSCLC): A Large Retrospective Multicenter Study

Background: In this study, we explored the relationship between                  neutrophil-to-lymphocyte ratio (NLR) and grade 3 or higher treatment related small bowel toxicity and treatment outcome of patients with rectal cancer undergoing capecitabine and concurrent intensity modulated radiotherapy (IMRT). Materials and Methods: From the year of 2012 to 2013, 117 rectal cancer ...

BACKGROUND: The preoperative neutrophil-to-lymphocyte ratio (NLR) and the platelet-to-lymphocyte ratio (PLR) are associated with poor prognosis of gastric cancer. We aimed to determine whether the combination of NLR and PLR (NLR-PLR) could better predict survival of patients after curative resection for stage I-II gastric cancer.. METHODS: We collected data from the medical records of patients with stage I-II gastric cancer undergoing curative resection between December 2000 and November 2012 at the Sun Yat-sen Cancer Center. The preoperative NLR-PLR was calculated as follows: patients with both elevated NLR (≥2.1) and PLR (≥120) were given a score of 2, and patients with only one or neither were given a score of 1 or 0, respectively.. RESULTS: Kaplan-Meier analysis and log-rank tests revealed significant differences in overall survival (OS) among patients with NLR-PLR scores of 0, 1 and 2 (P , 0.001). Multivariate analysis showed that OS was independently associated with the NLR-PLR score ...

The prognostic significance of neutrophil-to-lymphocyte ratio at different time points in patients with hepatocellular carcinoma receiving liver resection

Postoperative neutrophil-to-lymphocyte ratio change is a potential marker for the early detection of recurrence in urothelial carcinoma

The application of fluid shear stress on leukocytes is critical for physiological functions including initial adhesion to the endothelium, the formation of pseudopods, and migration into tissues. The formyl peptide receptor (FPR) on neutrophils, which binds to formyl-methionyl-leucyl-phenylalanine (fMLP) and plays a role in neutrophil chemotaxis, has been implicated as a fluid shear stress sensor that controls pseudopod formation. The role of shear forces on earlier indicators of neutrophil activation, such as L-selectin shedding and α(M)β(2) integrin activation, remains unclear. Here, human neutrophils exposed to uniform shear stress (0.1-4.0 dyn/cm(2)) in a cone-and-plate viscometer for 1-120 min showed a significant reduction in both α(M)β(2) integrin activation and L-selectin shedding after stimulation with 0.5 nM of fMLP. Neutrophil resistance to activation was directly linked to fluid shear stress, as the response increased in a shear stress force- and time-dependent manner. Significant shear

TY - JOUR. T1 - Inhibition of CD18-dependent neutrophil adherence reduces organ injury after hemorrhagic shock in primates. AU - Mileski, W. J.. AU - Winn, R. K.. AU - Vedder, N. B.. AU - Pohlman, T. H.. AU - Harlan, J. M.. AU - Rice, C. L.. PY - 1990. Y1 - 1990. N2 - Neutrophil adherence or aggregation may be important in the development of organ injury after hemorrhagic shock. Monoclonal antibody (MAb) 60.3 prevents both adherence and aggregation. Therefore we investigated MAb 60.3 treatment in prevention of organ injury after hemorrhagic shock in rhesus monkeys (Macaca mulatta). We performed esophagogastroscopy and placed catheters to measure cardiac output, mean arterial pressure, arterial blood gases, and urine output. Blood was removed to decrease CO to 30% of baseline for 90 minutes. Just before resuscitation, MAb 60.3 (2 mg/kg) or saline solution (control) was administered intravenously. Monitoring and fluid resuscitation continued for 24 hours, with lactated Ringers solution given as a ...

TY - JOUR. T1 - Adherent neutrophils activate endothelial myosin light chain kinase. T2 - Role in transendothelial migration. AU - Garcia, Joe G.N.. AU - Verin, Alexander D.. AU - Herenyiova, Maria. AU - English, Denis. PY - 1998/5/1. Y1 - 1998/5/1. N2 - Increased vascular endothelial cell (EC) permeability and neutrophilic leukocyte (PMN) diapedesis through paracellular gaps are cardinal features of acute inflammation. Activation of the EC contractile apparatus is necessary and sufficient to increase vascular permeability in specific models of EC barrier dysfunction. However, it is unknown whether EC contraction with subsequent paracellular gap formation is required for PMN transendothelial migration in response to chemotactic factors. To test this possibility, we assessed migration of human PMNs across confluent bovine pulmonary arterial EC monolayers. Transendothelial PMN migration in the absence of a chemotactic gradient was minimal, whereas abluminal addition of leukotriene B4 (LTB4; 5 μM) ...

Role of Neutrophils in Fibrin Structure and Function: How do Cells, Fibrin and Neutrophil Extracellular Traps (NETs) Integrate in Thrombi and Blood Cl, School of Medicine, University of Leeds

Immunoglobulin intravenous (IVIG) is widely used in mucocutaneous lymph node syndrome, known as Kawasaki disease (KD). However, the patients inflammatory response during usage remains unclear. In the present study, the association between inflammatory response and lymphocyte count in children with KD from different ages was evaluated before and after IVIG. The medical records of 50 children with KD were retrospectively reviewed and divided into five groups according to age. As compared with the data from healthy children, the relative neutrophil count of all children with KD was increased, and that of lymphocytes was decreased. The neutrophil/lymphocyte ratio (NLR) was different among all groups and was higher in children aged ≥4 years, as compared with other groups. Following IVIG, the relative neutrophil and lymphocyte counts of all children with KD returned to normal levels. The altered levels of neutrophils and lymphocytes were found to be linearly correlated. The correlation coefficient in the

The presence of anti-neutrophil cytoplasmic antibodies (ANCA) in Wegeners granulomatosis (WG), implicate the neutrophil as a key effector cell. Previous studies have reported elevated neutrophil counts in the lung although the determinants of neutrophil chemotaxis in the WG lung are unknown.. BALF cell counts, myeloperoxidase (MPO) and chemokines were measured in 27 patients with WG, 20 disease controls with idiopathic pulmonary fibrosis (IPF) and 6 healthy controls. CXCL-8, IL-1β, ENA-78, G-CSF and GM-CSF were measured by ELISA. The neutrophil chemotactic potential of BALF was investigated using the under agarose method and specific antibodies examined the role of CXCL-8 and IL-1β.. WG BALF had an increased neutrophil percentage and elevated MPO, CXCL-8 and G-CSF concentrations compared with healthy controls. Chemotaxis of control neutrophils towards BALF from patients with active (p=0.006) and remission WG (p=0.077) and IPF patients (p=0.001) was increased compared with normal controls. ...

Background: Clinical and experimental studies showing lung damage associated with biologically active neutrophil derivatives suggests the possibility that intrauterine neutrophil activation may predispose to the development of pulmonary haemorrhage in extremely low birthweight infants early after birth.. Objectives: To assess neutrophil functional activity in cord blood from extremely low birthweight infants who subsequently developed severe pulmonary haemorrhage.. Methods: Neutrophil functional activity was evaluated in the cord blood of preterm neonates (gestational age ,28 weeks and weight ,800 g) who developed pulmonary haemorrhage (n = 6) and in controls who did not (n = 6). Infants with congenital abnormalities and noteworthy maternal complications such as diabetes, pre-eclampsia, haemorrhagic disorders, and connective tissue disease were excluded. Neutrophils isolated from cord blood immediately after delivery were tested to evaluate neutrophil chemotaxis, random motility, and ...

alpha-Tocopherol augmentation in human neutrophils was investigated for effects on neutrophil activation and tyrosine phosphorylation of proteins, through its modulation of protein kinase C (PKC) and tyrosine phosphatase activities. Incubation of neutrophils with alpha-tocopherol succinate (TS) resulted in a dose-dependent incorporation into cell membranes, up to 2.5 nmol/2 X 10(6) cells. A saturating dose of TS (40 mumol/l) inhibited oxidant production by neutrophils stimulated with phorbol myristate acetate (PMA) or opsonized zymosan (OZ) by 86 and 57%, as measured by luminol-amplified chemiluminescence (CL). With PMA, TS inhibited CL generation to a similar extent to staurosporine (10 nmol/l) or genistein (100 mumol/l), and much more than Trolox (40 mumol/l). With OZ, TS inhibited CL to a similar extent to Trolox. Neutrophil PKC activity was inhibited 50% or more by TS or staurosporine. the enzyme activity was unaffected by genistein or Trolox, indicating a specific interaction of ...

Retinoid agonist Am80-enhanced neutrophil bactericidal activity arising from granulopoiesis in vitro and in a neutropenic mouse model.

Neutrophil to lymphocyte ratio see Neutrophil to lymphocyte ratio for subarachnoid hemorrhage. see Neutrophil to lymphocyte ratio for glioma. see Neutrophil to lymphocyte ratio for intracerebral hemorrhage. Normal Neutrophil to lymphocyte ratio values in an adult, non-geriatric, population in good health are between 0.78 and 3.53. These data may help the researcher as the clinician searching for a cut-off for the NLR, until now lacking