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Sample records for ccl3-mediated neutrophil recruitment

  1. Intracellular signalling during neutrophil recruitment.

    PubMed

    Mócsai, Attila; Walzog, Barbara; Lowell, Clifford A

    2015-08-01

    Recruitment of leucocytes such as neutrophils to the extravascular space is a critical step of the inflammation process and plays a major role in the development of various diseases including several cardiovascular diseases. Neutrophils themselves play a very active role in that process by sensing their environment and responding to the extracellular cues by adhesion and de-adhesion, cellular shape changes, chemotactic migration, and other effector functions of cell activation. Those responses are co-ordinated by a number of cell surface receptors and their complex intracellular signal transduction pathways. Here, we review neutrophil signal transduction processes critical for recruitment to the site of inflammation. The two key requirements for neutrophil recruitment are the establishment of appropriate chemoattractant gradients and the intrinsic ability of the cells to migrate along those gradients. We will first discuss signalling steps required for sensing extracellular chemoattractants such as chemokines and lipid mediators and the processes (e.g. PI3-kinase pathways) leading to the translation of extracellular chemoattractant gradients to polarized cellular responses. We will then discuss signal transduction by leucocyte adhesion receptors (e.g. tyrosine kinase pathways) which are critical for adhesion to, and migration through the vessel wall. Finally, additional neutrophil signalling pathways with an indirect effect on the neutrophil recruitment process, e.g. through modulation of the inflammatory environment, will be discussed. Mechanistic understanding of these pathways provide better understanding of the inflammation process and may point to novel therapeutic strategies for controlling excessive inflammation during infection or tissue damage. PMID:25998986

  2. Mechanism of neutrophil recruitment to the lung after pulmonary contusion.

    PubMed

    Hoth, J Jason; Wells, Jonathan D; Hiltbold, Elizabeth M; McCall, Charles E; Yoza, Barbara K

    2011-06-01

    Blunt chest trauma resulting in pulmonary contusion is a common but poorly understood injury. We previously demonstrated that lung contusion activates localized and systemic innate immune mechanisms and recruits neutrophils to the injured lung. We hypothesized that the innate immune and inflammatory activation of neutrophils may figure prominently in the response to lung injury. To investigate this, we used a model of pulmonary contusion in the mouse that is similar to that observed clinically in humans and evaluated postinjury lung function and pulmonary neutrophil recruitment. Comparisons were made between injured mice with and without neutrophil depletion. We further examined the role of chemokines and adhesion receptors in neutrophil recruitment to the injured lung. We found that lung injury and resultant physiological dysfunction after contusion were dependent on the presence of neutrophils in the alveolar space. We show that CXCL1, CXCL2/3, and CXCR2 are involved in neutrophil recruitment to the lung after injury and that intercellular adhesion molecule 1 is locally expressed and actively participates in this process. Injured gp91-deficient mice showed improved lung function, indicating that oxidant production by neutrophil NADPH oxidase mediates lung dysfunction after contusion. These data suggest that both neutrophil presence and function are required for lung injury after lung contusion. PMID:21330942

  3. Chemokine CXCL1 mediated neutrophil recruitment: Role of glycosaminoglycan interactions.

    PubMed

    Sawant, Kirti V; Poluri, Krishna Mohan; Dutta, Amit K; Sepuru, Krishna Mohan; Troshkina, Anna; Garofalo, Roberto P; Rajarathnam, Krishna

    2016-01-01

    The chemokine CXCL1/MGSA plays a pivotal role in the host immune response by recruiting and activating neutrophils for microbial killing at the tissue site. CXCL1 exists reversibly as monomers and dimers, and mediates its function by binding glycosaminoglycans (GAG) and CXCR2 receptor. We recently showed that both monomers and dimers are potent CXCR2 agonists, the dimer is the high-affinity GAG ligand, lysine and arginine residues located in two non-overlapping domains mediate GAG interactions, and there is extensive overlap between GAG and receptor-binding domains. To understand how these structural properties influence in vivo function, we characterized peritoneal neutrophil recruitment of a trapped monomer and trapped dimer and a panel of WT lysine/arginine to alanine mutants. Monomers and dimers were active, but WT was more active indicating synergistic interactions promote recruitment. Mutants from both domains showed reduced GAG heparin binding affinities and reduced neutrophil recruitment, providing compelling evidence that both GAG-binding domains mediate in vivo trafficking. Further, mutant of a residue that is involved in both GAG binding and receptor signaling showed the highest reduction in recruitment. We conclude that GAG interactions and receptor activity of CXCL1 monomers and dimers are fine-tuned to regulate neutrophil trafficking for successful resolution of tissue injury. PMID:27625115

  4. CXCL5 Drives Neutrophil Recruitment in TH17-Mediated GN

    PubMed Central

    Disteldorf, Erik M.; Krebs, Christian F.; Paust, Hans-Joachim; Turner, Jan-Eric; Nouailles, Geraldine; Tittel, André; Meyer-Schwesinger, Catherine; Stege, Gesa; Brix, Silke; Velden, Joachim; Wiech, Thorsten; Helmchen, Udo; Steinmetz, Oliver M.; Peters, Anett; Bennstein, Sabrina B.; Kaffke, Anna; Llanto, Chrystel; Lira, Sergio A.; Mittrücker, Hans-Willi; Stahl, Rolf A.K.; Kurts, Christian; Kaufmann, Stefan H.E.

    2015-01-01

    Neutrophil trafficking to sites of inflammation is essential for the defense against bacterial and fungal infections, but also contributes to tissue damage in TH17-mediated autoimmunity. This process is regulated by chemokines, which often show an overlapping expression pattern and function in pathogen- and autoimmune-induced inflammatory reactions. Using a murine model of crescentic GN, we show that the pathogenic TH17/IL-17 immune response induces chemokine (C-X-C motif) ligand 5 (CXCL5) expression in kidney tubular cells, which recruits destructive neutrophils that contribute to renal tissue injury. By contrast, CXCL5 was dispensable for neutrophil recruitment and effective bacterial clearance in a murine model of acute bacterial pyelonephritis. In line with these findings, CXCL5 expression was highly upregulated in the kidneys of patients with ANCA-associated crescentic GN as opposed to patients with acute bacterial pyelonephritis. Our data therefore identify CXCL5 as a potential therapeutic target for the restriction of pathogenic neutrophil infiltration in TH17-mediated autoimmune diseases while leaving intact the neutrophil function in protective immunity against invading pathogens. PMID:24904089

  5. Facilitation of Allergic Sensitization and Allergic Airway Inflammation by Pollen-Induced Innate Neutrophil Recruitment.

    PubMed

    Hosoki, Koa; Aguilera-Aguirre, Leopoldo; Brasier, Allan R; Kurosky, Alexander; Boldogh, Istvan; Sur, Sanjiv

    2016-01-01

    Neutrophil recruitment is a hallmark of rapid innate immune responses. Exposure of airways of naive mice to pollens rapidly induces neutrophil recruitment. The innate mechanisms that regulate pollen-induced neutrophil recruitment and the contribution of this neutrophilic response to subsequent induction of allergic sensitization and inflammation need to be elucidated. Here we show that ragweed pollen extract (RWPE) challenge in naive mice induces C-X-C motif ligand (CXCL) chemokine synthesis, which stimulates chemokine (C-X-C motif) receptor 2 (CXCR2)-dependent recruitment of neutrophils into the airways. Deletion of Toll-like receptor 4 (TLR4) abolishes CXCL chemokine secretion and neutrophil recruitment induced by a single RWPE challenge and inhibits induction of allergic sensitization and airway inflammation after repeated exposures to RWPE. Forced induction of CXCL chemokine secretion and neutrophil recruitment in mice lacking TLR4 also reconstitutes the ability of multiple challenges of RWPE to induce allergic airway inflammation. Blocking RWPE-induced neutrophil recruitment in wild-type mice by administration of a CXCR2 inhibitor inhibits the ability of repeated exposures to RWPE to stimulate allergic sensitization and airway inflammation. Administration of neutrophils derived from naive donor mice into the airways of Tlr4 knockout recipient mice after each repeated RWPE challenge reconstitutes allergic sensitization and inflammation in these mice. Together these observations indicate that pollen-induced recruitment of neutrophils is TLR4 and CXCR2 dependent and that recruitment of neutrophils is a critical rate-limiting event that stimulates induction of allergic sensitization and airway inflammation. Inhibiting pollen-induced recruitment of neutrophils, such as by administration of CXCR2 antagonists, may be a novel strategy to prevent initiation of pollen-induced allergic airway inflammation. PMID:26086549

  6. Neutrophil recruitment by allergens contribute to allergic sensitization and allergic inflammation

    PubMed Central

    Hosoki, Koa; Boldogh, Istvan; Sur, Sanjiv

    2016-01-01

    Purpose of review To discuss the presence and role of neutrophils in asthma and allergic diseases, and outline importance of pollen and cat dander-induced innate neutrophil recruitment in induction of allergic sensitization and allergic inflammation. Recent findings Uncontrolled asthma is associated with elevated numbers of neutrophils, and levels of neutrophil-attracting chemokine IL-8 and IL-17 in BAL fluids. These parameters negatively correlate with lung function. Pollen allergens and cat dander recruit neutrophils to the airways in a TLR4, MD2 and CXCR2-dependent manner. Repeated recruitment of activated neutrophils by these allergens facilitates allergic sensitization and airway inflammation. Inhibition of neutrophil recruitment with CXCR2 inhibitor, disruption of TLR4, or siRNA against MD2 also inhibits allergic inflammation. The molecular mechanisms by which neutrophils shift the inflammatory response of the airways to inhaled allergens to an allergic phenotype is an area of active research. Summary Recent studies have revealed that neutrophil recruitment is important in development of allergic sensitization and inflammation. Inhibition of neutrophils recruitment may be strategy to control allergic inflammation. PMID:26694038

  7. Visualization of Signaling Molecules During Neutrophil Recruitment in Transgenic Mice Expressing FRET Biosensors.

    PubMed

    Mizuno, Rei; Kamioka, Yuji; Sakai, Yoshiharu; Matsuda, Michiyuki

    2016-01-01

    A number of chemical mediators regulate neutrophil recruitment to inflammatory sites either positively or negatively. Although the actions of each chemical mediator on the intracellular signaling networks controlling cell migration have been studied with neutrophils cultured in vitro, how such chemical mediators act cooperatively or counteractively in vivo remains largely unknown. To understand the mechanisms regulating neutrophil recruitment to the inflamed intestine in vivo, we recently generated transgenic mice expressing biosensors based on FRET (Förster resonance energy transfer) and set up two-photon excitation microscopy to observe the gastrointestinal tract in living mice. By measuring FRET in neutrophils, we showed activity changes of protein kinases in the neutrophils recruited to inflamed intestines. In this chapter, we describe the protocol used to visualize the protein kinase activities in neutrophils of the inflamed intestine of transgenic mice expressing the FRET biosensors. PMID:27246030

  8. Neutrophil Recruitment to Lymph Nodes Limits Local Humoral Response to Staphylococcus aureus

    PubMed Central

    Kamenyeva, Olena; Boularan, Cedric; Kabat, Juraj; Cheung, Gordon Y. C.; Cicala, Claudia; Yeh, Anthony J.; Chan, June L.; Periasamy, Saravanan; Otto, Michael; Kehrl, John H.

    2015-01-01

    Neutrophils form the first line of host defense against bacterial pathogens. They are rapidly mobilized to sites of infection where they help marshal host defenses and remove bacteria by phagocytosis. While splenic neutrophils promote marginal zone B cell antibody production in response to administered T cell independent antigens, whether neutrophils shape humoral immunity in other lymphoid organs is controversial. Here we investigate the neutrophil influx following the local injection of Staphylococcus aureus adjacent to the inguinal lymph node and determine neutrophil impact on the lymph node humoral response. Using intravital microscopy we show that local immunization or infection recruits neutrophils from the blood to lymph nodes in waves. The second wave occurs temporally with neutrophils mobilized from the bone marrow. Within lymph nodes neutrophils infiltrate the medulla and interfollicular areas, but avoid crossing follicle borders. In vivo neutrophils form transient and long-lived interactions with B cells and plasma cells, and their depletion augments production of antigen-specific IgG and IgM in the lymph node. In vitro activated neutrophils establish synapse- and nanotube-like interactions with B cells and reduce B cell IgM production in a TGF- β1 dependent manner. Our data reveal that neutrophils mobilized from the bone marrow in response to a local bacterial challenge dampen the early humoral response in the lymph node. PMID:25884622

  9. Cxcl8 (Interleukin-8) mediates neutrophil recruitment and behavior in the zebrafish inflammatory response

    PubMed Central

    de Oliveira, Sofia; Reyes-Aldasoro, Constantino C.; Candel, Sergio; Renshaw, Stephen A.; Mulero, Victoriano; Calado, Ângelo

    2013-01-01

    Neutrophils play a pivotal role in the innate immune response. The small cytokine CXCL8 (also known as interleukin-8 or IL-8) is known to be one of the most potent chemoattractant molecules which, among several other functions, is responsible for guiding neutrophils through the tissue matrix until they reach sites of injury. Unlike mice and rats that lack a CXCL8 homologue, zebrafish has two distinct CXCL8 homologues: Cxcl8-l1 and Cxcl8-l2. Cxcl8-l1 is known to be up-regulated under inflammatory conditions caused by bacterial or chemical insult but until now, the role of Cxcl8s in neutrophil recruitment has not been studied. Here, we show that both Cxcl8 genes are up-regulated in response to an acute inflammatory stimulus, and that both are crucial for normal neutrophil recruitment to the wound and normal resolution of inflammation. Additionally, we have analyzed neutrophil migratory behavior through tissues to the site of injury in vivo, using open-access phagocyte tracking software, PhagoSight. Surprisingly, we observed that in the absence of these chemokines, the speed of the neutrophils migrating to the wound was significantly increased in comparison to control neutrophils, although the directionality was not affected. Our analysis suggests that zebrafish may possess a sub-population of neutrophils whose recruitment to inflamed areas occurs independently of Cxcl8 chemokines. Moreover, we report that Cxcl8-l2 signaled through Cxcr2 for inducing neutrophil recruitment. Our study, therefore, confirms the zebrafish as an excellent in vivo model to shed light on the roles of CXCL8 in neutrophil biology. PMID:23509368

  10. Fatty acids as modulators of neutrophil recruitment, function and survival.

    PubMed

    Rodrigues, Hosana G; Takeo Sato, Fabio; Curi, Rui; Vinolo, Marco A R

    2016-08-15

    Neutrophils are well-known to act in the destruction of invading microorganisms. They have also been implicated in the activation of other immune cells including B- and T-lymphocytes and in the resolution of inflammation and tissue regeneration. Neutrophils are produced in the bone marrow and released into the circulation from where they migrate to tissues to perform their effector functions. Neutrophils are in constant contact with fatty acids that can modulate their function, activation and fate (survival or cell death) through different mechanisms. In this review, the effects of fatty acids pertaining to five classes, namely, long-chain saturated fatty acids (LCSFAs), short-chain fatty acids (SCFAs), and omega-3 (n-3), omega-6 (n-6) and omega-9 (n-9) unsaturated fatty acids, on neutrophils and the relevance of these effects for disease development are discussed. PMID:25987417

  11. Neutrophil recruitment in endotoxin-induced murine mastitis is strictly dependent on mammary alveolar macrophages

    PubMed Central

    Elazar, Sharon; Gonen, Erez; Livneh-Kol, Ayala; Rosenshine, Ilan; Shpigel, Nahum Yehuda

    2009-01-01

    Mastitis, inflammation of the mammary tissue, is a common disease in dairy animals and mammary pathogenic Escherichia coli (MPEC) is a leading cause of the disease. Lipopolysaccharide (LPS) is an important virulence factor of MPEC and inoculation of the mammary glands with bacterial LPS is sufficient to induce an inflammatory response. We previously showed using adoptive transfer of normal macrophages into the mammary gland of TLR4-deficient C3H/HeJ mice that LPS/TLR4 signaling on mammary alveolar macrophages is sufficient to elicit neutrophil recruitment into the alveolar space. Here we show that TLR4-normal C3H/HeN mice, depleted of alveolar macrophages, were completely refractory to LPS intramammary challenge. These results indicate that alveolar macrophages are both sufficient and essential for neutrophil recruitment elicited by LPS/TLR4 signaling in the mammary gland. Using TNFα gene-knockout mice and adoptive transfer of wild-type macrophages, we show here that TNFα produced by mammary alveolar macrophages in response to LPS/TLR4 signaling is an essential mediator eliciting blood neutrophil recruitment into the milk spaces. Furthermore, using the IL8 receptor or IL1 receptor gene-knockout mice we observed abrogated recruitment of neutrophils into the mammary gland and their entrapment on the basal side of the alveolar epithelium in response to intramammary LPS challenge. Adoptive transfer of wild-type neutrophils to IL1 receptor knockout mice, just before LPS challenge, restored normal neutrophil recruitment into the milk spaces. We conclude that neutrophil recruitment to the milk spaces is: (i) mediated through TNFα, which is produced by alveolar macrophages in response to LPS/TLR4 signaling and (ii) is dependent on IL8 and IL1β signaling and regulated by iNOS-derived NO. PMID:19828114

  12. Orai1 controls C5a-induced neutrophil recruitment in inflammation.

    PubMed

    Sogkas, Georgios; Vögtle, Timo; Rau, Eduard; Gewecke, Britta; Stegner, David; Schmidt, Reinhold E; Nieswandt, Bernhard; Gessner, J Engelbert

    2015-07-01

    Stromal interaction molecule 1 (STIM1)-dependent store operated calcium-entry (SOCE) through Orai1-mediated calcium (Ca(2+) ) influx is considered a major pathway of Ca(2+) signaling, serving T-cell, mast cell, and platelet responses. Here, we show that Orai1 is critical for neutrophil function. Orai1-deficient neutrophils present defects in fMLP and complement C5a-induced Ca(2+) influx and migration, although they respond normally to another chemoattractant, CXCL2. Up until now, no specific contribution of Orai1 independent from STIM1 or SOCE has been recognized in immune cells. Here, we observe that Orai1-deficient neutrophils exhibit normal STIM1-dependent SOCE and STIM1-deficient neutrophils respond to fMLP and C5a efficiently. Despite substantial cytokine production, Orai1(-/-) chimeric mice show impaired neutrophil recruitment in LPS-induced peritonitis. Moreover, Orai1 deficiency results in profoundly defective C5a-triggered neutrophil lung recruitment in hypersensitivity pneumonitis. Comparative evaluation of inflammation in Stim1(-/-) chimeras reveals a distinct pathogenic contribution of STIM1, including its involvement in IgG-induced C5a production. Our data establish Orai1 as key signal mediator of C5aR activation, contributing to inflammation by a STIM1-independent pathway of Ca(2+) -influx in neutrophils. PMID:25912155

  13. CARD9-Dependent Neutrophil Recruitment Protects against Fungal Invasion of the Central Nervous System

    PubMed Central

    Swamydas, Muthulekha; Rodriguez, Carlos A.; Lim, Jean K.; Mendez, Laura M.; Fink, Danielle L.; Hsu, Amy P.; Zhai, Bing; Karauzum, Hatice; Mikelis, Constantinos M.; Rose, Stacey R.; Ferre, Elise M. N.; Yockey, Lynne; Lemberg, Kimberly; Kuehn, Hye Sun; Rosenzweig, Sergio D.; Lin, Xin; Chittiboina, Prashant; Datta, Sandip K.; Belhorn, Thomas H.; Weimer, Eric T.; Hernandez, Michelle L.; Hohl, Tobias M.; Kuhns, Douglas B.; Lionakis, Michail S.

    2015-01-01

    Candida is the most common human fungal pathogen and causes systemic infections that require neutrophils for effective host defense. Humans deficient in the C-type lectin pathway adaptor protein CARD9 develop spontaneous fungal disease that targets the central nervous system (CNS). However, how CARD9 promotes protective antifungal immunity in the CNS remains unclear. Here, we show that a patient with CARD9 deficiency had impaired neutrophil accumulation and induction of neutrophil-recruiting CXC chemokines in the cerebrospinal fluid despite uncontrolled CNS Candida infection. We phenocopied the human susceptibility in Card9-/- mice, which develop uncontrolled brain candidiasis with diminished neutrophil accumulation. The induction of neutrophil-recruiting CXC chemokines is significantly impaired in infected Card9-/- brains, from both myeloid and resident glial cellular sources, whereas cell-intrinsic neutrophil chemotaxis is Card9-independent. Taken together, our data highlight the critical role of CARD9-dependent neutrophil trafficking into the CNS and provide novel insight into the CNS fungal susceptibility of CARD9-deficient humans. PMID:26679537

  14. CARD9-Dependent Neutrophil Recruitment Protects against Fungal Invasion of the Central Nervous System.

    PubMed

    Drummond, Rebecca A; Collar, Amanda L; Swamydas, Muthulekha; Rodriguez, Carlos A; Lim, Jean K; Mendez, Laura M; Fink, Danielle L; Hsu, Amy P; Zhai, Bing; Karauzum, Hatice; Mikelis, Constantinos M; Rose, Stacey R; Ferre, Elise M N; Yockey, Lynne; Lemberg, Kimberly; Kuehn, Hye Sun; Rosenzweig, Sergio D; Lin, Xin; Chittiboina, Prashant; Datta, Sandip K; Belhorn, Thomas H; Weimer, Eric T; Hernandez, Michelle L; Hohl, Tobias M; Kuhns, Douglas B; Lionakis, Michail S

    2015-12-01

    Candida is the most common human fungal pathogen and causes systemic infections that require neutrophils for effective host defense. Humans deficient in the C-type lectin pathway adaptor protein CARD9 develop spontaneous fungal disease that targets the central nervous system (CNS). However, how CARD9 promotes protective antifungal immunity in the CNS remains unclear. Here, we show that a patient with CARD9 deficiency had impaired neutrophil accumulation and induction of neutrophil-recruiting CXC chemokines in the cerebrospinal fluid despite uncontrolled CNS Candida infection. We phenocopied the human susceptibility in Card9-/- mice, which develop uncontrolled brain candidiasis with diminished neutrophil accumulation. The induction of neutrophil-recruiting CXC chemokines is significantly impaired in infected Card9-/- brains, from both myeloid and resident glial cellular sources, whereas cell-intrinsic neutrophil chemotaxis is Card9-independent. Taken together, our data highlight the critical role of CARD9-dependent neutrophil trafficking into the CNS and provide novel insight into the CNS fungal susceptibility of CARD9-deficient humans. PMID:26679537

  15. NK cells promote neutrophil recruitment in the brain during sepsis-induced neuroinflammation

    PubMed Central

    He, Hao; Geng, Tingting; Chen, Piyun; Wang, Meixiang; Hu, Jingxia; Kang, Li; Song, Wengang; Tang, Hua

    2016-01-01

    Sepsis could affect the central nervous system and thus induces neuroinflammation, which subsequently leads to brain damage or dysfunction. However, the mechanisms of generation of neuroinflammation during sepsis remain poorly understood. By administration of lipopolysaccharides (LPS) in mice to mimic sepsis, we found that shortly after opening the blood–brain barrier, conventional CD11b+CD27+ NK subset migrated into the brain followed by subsequent neutrophil infiltration. Interestingly, depletion of NK cells prior to LPS treatment severely impaired neutrophil recruitment in the inflamed brain. By in vivo recruitment assay, we found that brain-infiltrated NK cells displayed chemotactic activity to neutrophils, which depended on the higher expression of chemokines such as CXCL2. Moreover, microglia were also responsible for neutrophil recruitment, and their chemotactic activity was significantly impaired by ablation of NK cells. Furthermore, depletion of NK cells could significantly ameliorate depression-like behavior in LPS-treated mice. These data indicated a NK cell-regulated neutrophil recruitment in the blamed brain, which also could be seen on another sepsis model, cecal ligation and puncture. So, our findings revealed an important scenario in the generation of sepsis-induced neuroinflammation. PMID:27270556

  16. NK cells promote neutrophil recruitment in the brain during sepsis-induced neuroinflammation.

    PubMed

    He, Hao; Geng, Tingting; Chen, Piyun; Wang, Meixiang; Hu, Jingxia; Kang, Li; Song, Wengang; Tang, Hua

    2016-01-01

    Sepsis could affect the central nervous system and thus induces neuroinflammation, which subsequently leads to brain damage or dysfunction. However, the mechanisms of generation of neuroinflammation during sepsis remain poorly understood. By administration of lipopolysaccharides (LPS) in mice to mimic sepsis, we found that shortly after opening the blood-brain barrier, conventional CD11b(+)CD27(+) NK subset migrated into the brain followed by subsequent neutrophil infiltration. Interestingly, depletion of NK cells prior to LPS treatment severely impaired neutrophil recruitment in the inflamed brain. By in vivo recruitment assay, we found that brain-infiltrated NK cells displayed chemotactic activity to neutrophils, which depended on the higher expression of chemokines such as CXCL2. Moreover, microglia were also responsible for neutrophil recruitment, and their chemotactic activity was significantly impaired by ablation of NK cells. Furthermore, depletion of NK cells could significantly ameliorate depression-like behavior in LPS-treated mice. These data indicated a NK cell-regulated neutrophil recruitment in the blamed brain, which also could be seen on another sepsis model, cecal ligation and puncture. So, our findings revealed an important scenario in the generation of sepsis-induced neuroinflammation. PMID:27270556

  17. Rapid lung cytokine accumulation and neutrophil recruitment after lipopolysaccharide inhalation by cigarette smokers and nonsmokers.

    PubMed

    Wesselius, L J; Nelson, M E; Bailey, K; O'Brien-Ladner, A R

    1997-01-01

    Inhalation of lipopolysaccharide (LPS) by humans rapidly recruits neutrophils to alveolar structures. Recruitment of neutrophils may be mediated in part by intrapulmonary release of cytokines such as tumor necrosis factor-alpha, interleukin (IL)-1beta, and IL-8, although the kinetics of cytokine accumulation and neutrophil recruitment to the lungs after LPS inhalation have not been determined. Release of some cytokines in response to LPS is reported to be decreased in smokers' alveolar macrophages compared with nonsmokers', suggesting responses to LPS may differ in smokers (S) and nonsmokers (NS). To assess the kinetics of early cytokine accumulation after LPS inhalation and to compare inflammation induced in LPS-exposed S and NS, we performed bronchoalveolar lavage (BAL) in 28 subjects (14 NS and 14 S) at 90 or 240 minutes after inhalation of aerosolized LPS (30 microg). BAL performed at 90 and 240 minutes after LPS inhalation recovered increased numbers of neutrophils and lymphocytes in both NS and S compared with an unexposed control group (10 NS, 10 S), with greater recovery of neutrophils in S than NS (p < 0.001). BAL fluid supernate concentrations of IL-8, IL-1beta, and tumor necrosis factor-alpha at 90 minutes were increased in S and NS compared with an unexposed control group. IL-8 and tumor necrosis factor-alpha concentrations were similar in S and NS; however, IL-1beta concentrations were greater in S (p < 0.005). BAL fluid concentrations of IL-1beta and IL-8 at 90 minutes correlated with absolute neutrophil recovery in S and NS. These findings suggest that the rapid accumulation of cytokines, particularly IL-1beta and IL-8, contributes to lung neutrophil recruitment after LPS inhalation. In addition, parameters of pulmonary inflammation present in S after LPS inhalation are similar to or increased compared with those present in NS. PMID:9011586

  18. Protection from septic peritonitis by rapid neutrophil recruitment through omental high endothelial venules.

    PubMed

    Buscher, Konrad; Wang, Huiyu; Zhang, Xueli; Striewski, Paul; Wirth, Benedikt; Saggu, Gurpanna; Lütke-Enking, Stefan; Mayadas, Tanya N; Ley, Klaus; Sorokin, Lydia; Song, Jian

    2016-01-01

    Acute peritonitis is a frequent medical condition that can trigger severe sepsis as a life-threatening complication. Neutrophils are first-responders in infection but recruitment mechanisms to the abdominal cavity remain poorly defined. Here, we demonstrate that high endothelial venules (HEVs) of the greater omentum constitute a main entry pathway in TNFα-, Escherichia coli (E. coli)- and caecal ligation and puncture-induced models of inflammation. Neutrophil transmigration across HEVs is faster than across conventional postcapillary venules and requires a unique set of adhesion receptors including peripheral node addressin, E-, L-selectin and Mac-1 but not P-selectin or LFA-1. Omental milky spots readily concentrate intra-abdominal E. coli where macrophages and recruited neutrophils collaborate in phagocytosis and killing. Inhibition of the omental neutrophil response exacerbates septic progression of peritonitis. This data identifies HEVs as a clinically relevant vascular recruitment site for neutrophils in acute peritonitis that is indispensable for host defence against early systemic bacterial spread and sepsis. PMID:26940548

  19. Protection from septic peritonitis by rapid neutrophil recruitment through omental high endothelial venules

    PubMed Central

    Buscher, Konrad; Wang, Huiyu; Zhang, Xueli; Striewski, Paul; Wirth, Benedikt; Saggu, Gurpanna; Lütke-Enking, Stefan; Mayadas, Tanya N.; Ley, Klaus; Sorokin, Lydia; Song, Jian

    2016-01-01

    Acute peritonitis is a frequent medical condition that can trigger severe sepsis as a life-threatening complication. Neutrophils are first-responders in infection but recruitment mechanisms to the abdominal cavity remain poorly defined. Here, we demonstrate that high endothelial venules (HEVs) of the greater omentum constitute a main entry pathway in TNFα-, Escherichia coli (E. coli)- and caecal ligation and puncture-induced models of inflammation. Neutrophil transmigration across HEVs is faster than across conventional postcapillary venules and requires a unique set of adhesion receptors including peripheral node addressin, E-, L-selectin and Mac-1 but not P-selectin or LFA-1. Omental milky spots readily concentrate intra-abdominal E. coli where macrophages and recruited neutrophils collaborate in phagocytosis and killing. Inhibition of the omental neutrophil response exacerbates septic progression of peritonitis. This data identifies HEVs as a clinically relevant vascular recruitment site for neutrophils in acute peritonitis that is indispensable for host defence against early systemic bacterial spread and sepsis. PMID:26940548

  20. Tumor-Derived CXCL1 Promotes Lung Cancer Growth via Recruitment of Tumor-Associated Neutrophils

    PubMed Central

    Zhu, Ha; Xu, Junfang; Zheng, Yuanyuan; Cao, Xuetao

    2016-01-01

    Neutrophils have a traditional role in inflammatory process and act as the first line of defense against infections. Although their contribution to tumorigenesis and progression is still controversial, accumulating evidence recently has demonstrated that tumor-associated neutrophils (TANs) play a key role in multiple aspects of cancer biology. Here, we detected that chemokine CXCL1 was dramatically elevated in serum from 3LL tumor-bearing mice. In vitro, 3LL cells constitutively expressed and secreted higher level of CXCL1. Furthermore, knocking down CXCL1 expression in 3LL cells significantly hindered tumor growth by inhibiting recruitment of neutrophils from peripheral blood into tumor tissues. Additionally, tumor-infiltrated neutrophils expressed higher levels of MPO and Fas/FasL, which may be involved in TAN-mediated inhibition of CD4+ and CD8+ T cells. These results demonstrate that tumor-derived CXCL1 contributes to TANs infiltration in lung cancer which promotes tumor growth. PMID:27446967

  1. Activated human valvular interstitial cells sustain interleukin-17 production to recruit neutrophils in infective endocarditis.

    PubMed

    Yeh, Chiou-Yueh; Shun, Chia-Tung; Kuo, Yu-Min; Jung, Chiau-Jing; Hsieh, Song-Chou; Chiu, Yen-Ling; Chen, Jeng-Wei; Hsu, Ron-Bin; Yang, Chia-Ju; Chia, Jean-San

    2015-06-01

    The mechanisms that underlie valvular inflammation in streptococcus-induced infective endocarditis (IE) remain unclear. We previously demonstrated that streptococcal glucosyltransferases (GTFs) can activate human heart valvular interstitial cells (VIC) to secrete interleukin-6 (IL-6), a cytokine involved in T helper 17 (Th17) cell differentiation. Here, we tested the hypothesis that activated VIC can enhance neutrophil infiltration through sustained IL-17 production, leading to valvular damage. To monitor cytokine and chemokine production, leukocyte recruitment, and the induction or expansion of CD4(+) CD45RA(-) CD25(-) CCR6(+) Th17 cells, primary human VIC were cultured in vitro and activated by GTFs. Serum cytokine levels were measured using an enzyme-linked immunosorbent assay (ELISA), and neutrophils and Th17 cells were detected by immunohistochemistry in infected valves from patients with IE. The expression of IL-21, IL-23, IL-17, and retinoic acid receptor-related orphan receptor C (Rorc) was upregulated in GTF-activated VIC, which may enhance the proliferation of memory Th17 cells in an IL-6-dependent manner. Many chemokines, including chemokine (C-X-C motif) ligand 1 (CXCL1), were upregulated in GTF-activated VIC, which might recruit neutrophils and CD4(+) T cells. Moreover, CXCL1 production in VIC was induced in a dose-dependent manner by IL-17 to enhance neutrophil chemotaxis. CXCL1-expressing VIC and infiltrating neutrophils could be detected in infected valves, and serum concentrations of IL-17, IL-21, and IL-23 were increased in patients with IE compared to healthy donors. Furthermore, elevated serum IL-21 levels have been significantly associated with severe valvular damage, including rupture of chordae tendineae, in IE patients. Our findings suggest that VIC are activated by bacterial modulins to recruit neutrophils and that such activities might be further enhanced by the production of Th17-associated cytokines. Together, these factors can amplify

  2. Comparative Ability of Mesenchymal Stromal Cells from Different Tissues to Limit Neutrophil Recruitment to Inflamed Endothelium

    PubMed Central

    Munir, Hafsa; Luu, Nguyet-Thin; Clarke, Lewis S. C.; Nash, Gerard B.; McGettrick, Helen M.

    2016-01-01

    Mesenchymal stromal cells (MSC) are tissue-resident stromal cells capable of modulating immune responses, including leukocyte recruitment by endothelial cells (EC). However, the comparative potency of MSC from different sources in suppressing recruitment, and the necessity for close contact with endothelium remain uncertain, although these factors have implications for use of MSC in therapy. We thus compared the effects of MSC isolated from bone marrow, Wharton’s jelly, and trabecular bone on neutrophil recruitment to cytokine-stimulated EC, using co-culture models with different degrees of proximity between MSC and EC. All types of MSC suppressed neutrophil adhesion to inflamed endothelium but not neutrophil transmigration, whether directly incorporated into endothelial monolayers or separated from them by thin micropore filters. Further increase in the separation of the two cell types tended to reduce efficacy, although this diminution was least for the bone marrow MSC. Immuno-protective effects of MSC were also diminished with repeated passage; with BMMSC, but not WJMSC, completing losing their suppressive effect by passage 7. Conditioned media from all co-cultures suppressed neutrophil recruitment, and IL-6 was identified as a common bioactive mediator. These results suggest endogenous MSC have a homeostatic role in limiting inflammatory leukocyte infiltration in a range of tissues. Since released soluble mediators might have effects locally or remotely, infusion of MSC into blood or direct injection into target organs might be efficacious, but in either case, cross-talk between EC and MSC appears necessary. PMID:27171357

  3. Dual oxidase regulates neutrophil recruitment in allergic airways.

    PubMed

    Chang, Sandra; Linderholm, Angela; Franzi, Lisa; Kenyon, Nicholas; Grasberger, Helmut; Harper, Richart

    2013-12-01

    Enhanced reactive oxygen species production in allergic airways is well described and correlates with increased airway contractions, inflammatory cell infiltration, goblet cell metaplasia, and mucus hypersecretion. There is also an abundance of interleukin-4/interleukin-13 (IL-4/IL-13)- or interleukin-5-secreting cells that are thought to be central to the pathogenesis of allergic asthma. We postulated that the dual oxidases (DUOX1 and DUOX2), members of the nicotinamide adenine dinucleotide phosphate oxidase family that release hydrogen peroxide (H2O2) in the respiratory tract, are critical proteins in the pathogenesis of allergic airways. DUOX activity is regulated by cytokines, including IL-4 and IL-13, and DUOX-mediated H2O2 influences several important features of allergic asthma: mucin production, IL-8 secretion, and wound healing. The objective of this study was to establish the contribution of DUOXs to the development of allergic asthma in a murine model. To accomplish this goal, we utilized a DUOXA-deficient mouse model (Duoxa(-/-)) that lacked maturation factors for both DUOX1 and DUOX2. Our results are the first to demonstrate evidence of DUOX protein and DUOX functional activity in murine airway epithelium. We also demonstrate that DUOXA maturation factors are required for airway-specific H2O2 production and localization of DUOX to cilia of fully differentiated airway epithelial cells. We compared wild-type and Duoxa(-/-) mice in an ovalbumin exposure model to determine the role of DUOX in allergic asthma. In comparison to DUOX-intact mice, Duoxa(-/-) mice had reduced mucous cell metaplasia and lower levels of TH2 cytokine levels in bronchoalveolar fluid. In addition, increased airway resistance in response to methacholine was observed in Duoxa(+/+) mice, as expected, but was absent in Duoxa(-/-) mice. Surprisingly, Duoxa(-/-) mice had decreased influx of neutrophils in bronchoalveolar fluid and lung tissue sections associated with a lower level of the

  4. Dual Oxidase Regulates Neutrophil Recruitment in Allergic Airways

    PubMed Central

    Chang, Sandra; Linderholm, Angela; Franzi, Lisa; Kenyon, Nicholas; Grasberger, Helmut; Harper, Richart

    2013-01-01

    Enhanced reactive oxygen species production in allergic airways is well described, and correlates with increased airway contractions, inflammatory cell infiltration, goblet cell metaplasia, and mucus hypersecretion. There is also an abundance of interleukin-4/interleukin-13 (IL-4/IL-13) or interleukin-5-secreting cells that are thought to be central to the pathogenesis of allergic asthma. We postulated that dual oxidases (DUOX1 and DUOX2), members of the nicotinamide adenine dinucleotide phosphate oxidase family that release hydrogen peroxide (H2O2) in the respiratory tract, are critical proteins in the pathogenesis of allergic airways. DUOX activity is regulated by cytokines including IL-4 and IL-13, and DUOX-mediated H2O2 influences several important features of allergic asthma: mucin production, IL-8 secretion, and wound healing. The objective of this study was to establish the contribution of DUOX to the development of allergic asthma in a murine model. To accomplish this goal, we utilized a DUOXA-deficient mouse model (Duoxa−/−) that lacked maturation factors for both DUOX1 and DUOX2. Our results are the first to demonstrate evidence of DUOX protein and DUOX functional activity in murine airway epithelium. We also demonstrate that DUOXA maturation factors are required for airway-specific H2O2 production and localization of DUOX to cilia of fully differentiated airway epithelial cells. We compared wild-type and Duoxa−/− mice in an ovalbumin exposure model to determine the role of DUOX in allergic asthma. In comparison to DUOX-intact mice, Duoxa−/− mice had reduced mucous cell metaplasia, and lower levels of TH2 cytokine levels in bronchoalveolar fluid. In addition, increased airway resistance in response to methacholine was observed in Duoxa+/+ mice as expected, but was absent in Duoxa−/− mice. Surprisingly, Duoxa−/− mice had decreased influx of neutrophils in bronchoalveolar fluid and lung tissue sections associated with a lower level of

  5. Platelet serotonin promotes the recruitment of neutrophils to sites of acute inflammation in mice.

    PubMed

    Duerschmied, Daniel; Suidan, Georgette L; Demers, Melanie; Herr, Nadine; Carbo, Carla; Brill, Alexander; Cifuni, Stephen M; Mauler, Maximilian; Cicko, Sanja; Bader, Michael; Idzko, Marco; Bode, Christoph; Wagner, Denisa D

    2013-02-01

    The majority of peripheral serotonin is stored in platelets, which secrete it on activation. Serotonin releases Weibel-Palade bodies (WPBs) and we asked whether absence of platelet serotonin affects neutrophil recruitment in inflammatory responses. Tryptophan hydroxylase (Tph)1–deficient mice, lacking non-neuronal serotonin, showed mild leukocytosis compared with wild-type (WT), primarily driven by an elevated neutrophil count. Despite this, 50% fewer leukocytes rolled on unstimulated mesenteric venous endothelium of Tph1(-/-) mice. The velocity of rolling leukocytes was higher in Tph1(-/-) mice, indicating fewer selectin-mediated interactions with endothelium. Stimulation of endothelium with histamine, a secretagogue of WPBs, or injection of serotonin normalized the rolling in Tph1(-/-) mice. Diminished rolling in Tph1(-/-) mice resulted in reduced firm adhesion of leukocytes after lipopolysaccharide treatment. Blocking platelet serotonin uptake with fluoxetine in WT mice reduced serum serotonin by > 80% and similarly reduced leukocyte rolling and adhesion. Four hours after inflammatory stimulation, neutrophil extravasation into lung, peritoneum, and skin wounds was reduced in Tph1(-/-) mice, whereas in vitro neutrophil chemotaxis was independent of serotonin. Survival of lipopolysaccharide-induced endotoxic shock was improved in Tph1(-/-) mice. In conclusion, platelet serotonin promotes the recruitment of neutrophils in acute inflammation, supporting an important role for platelet serotonin in innate immunity. PMID:23243271

  6. Effect of boldine, secoboldine, and boldine methine on angiotensin II-induced neutrophil recruitment in vivo.

    PubMed

    Estellés, Rossana; Milian, Lara; Nabah, Yafa Naim Abu; Mateo, Teresa; Cerdá-Nicolás, Miguel; Losada, Mercedes; Ivorra, María Dolores; Issekutz, Andrew C; Cortijo, Julio; Morcillo, Esteban J; Blázquez, María Amparo; Sanz, María-Jesús

    2005-09-01

    Angiotensin-II (Ang-II) has inflammatory activity and is involved in different diseases associated with the cardiovascular system. This study has evaluated the effect of boldine (B), and two phenanthrene alkaloids semisynthesized by us, secoboldine (SB) and boldine methine (BM), on Ang-II-induced neutrophil recruitment. Intraperitoneal administration of 1 nM Ang-II induced significant neutrophil accumulation, which was maximal at 4-8 h. BM inhibited neutrophil infiltration into the peritoneal cavity at 4 h and 8 h by 73% and 77%, respectively, SB at 8 h by 55%, and B had no effect on this response. Although BM inhibited the release of cytokine-inducible neutrophil chemoattractant/keratinocyte-derived chemokine, macrophage inflammatory protein-2 (MIP-2), and platelet-activating factor (PAF) elicited by Ang-II, SB only reduced the release of MIP-2 after 4 h of its administration. Sixty-minute superfusion of the rat mesentery with 1 nM Ang-II induced a significant increase in the leukocyte-endothelial cell interactions and P-selectin up-regulation, which were inhibited by 1 microM BM and SB. The generation of reactive oxygen species (ROS) in endothelial cells stimulated with Ang-II was inhibited significantly by the three alkaloids tested. BM also diminished Ang-II-induced interleukin-8 release from endothelial cells and blocked the PAF receptor on human neutrophils (concentration of the compound needed to produce 50% inhibition value: 28.2 microM). Therefore, BM is a potent inhibitor of Ang-II-induced neutrophil accumulation in vivo. This effect appears to be mediated through inhibition of CXC chemokine and PAF release, ROS scavenging activity, and blockade of the PAF receptor. Thus, it may have potential therapeutic interest for the control of neutrophil recruitment that occurs in inflammation associated with elevated levels of Ang-II. PMID:15944212

  7. Circumventing Y. pestis Virulence by Early Recruitment of Neutrophils to the Lungs during Pneumonic Plague

    PubMed Central

    Vagima, Yaron; Zauberman, Ayelet; Levy, Yinon; Gur, David; Tidhar, Avital; Aftalion, Moshe; Shafferman, Avigdor; Mamroud, Emanuelle

    2015-01-01

    Pneumonic plague is a fatal disease caused by Yersinia pestis that is associated with a delayed immune response in the lungs. Because neutrophils are the first immune cells recruited to sites of infection, we investigated the mechanisms responsible for their delayed homing to the lung. During the first 24 hr after pulmonary infection with a fully virulent Y. pestis strain, no significant changes were observed in the lungs in the levels of neutrophils infiltrate, expression of adhesion molecules, or the expression of the major neutrophil chemoattractants keratinocyte cell-derived chemokine (KC), macrophage inflammatory protein 2 (MIP-2) and granulocyte colony stimulating factor (G-CSF). In contrast, early induction of chemokines, rapid neutrophil infiltration and a reduced bacterial burden were observed in the lungs of mice infected with an avirulent Y. pestis strain. In vitro infection of lung-derived cell-lines with a YopJ mutant revealed the involvement of YopJ in the inhibition of chemoattractants expression. However, the recruitment of neutrophils to the lungs of mice infected with the mutant was still delayed and associated with rapid bacterial propagation and mortality. Interestingly, whereas KC, MIP-2 and G-CSF mRNA levels in the lungs were up-regulated early after infection with the mutant, their protein levels remained constant, suggesting that Y. pestis may employ additional mechanisms to suppress early chemoattractants induction in the lung. It therefore seems that prevention of the early influx of neutrophils to the lungs is of major importance for Y. pestis virulence. Indeed, pulmonary instillation of KC and MIP-2 to G-CSF-treated mice infected with Y. pestis led to rapid homing of neutrophils to the lung followed by a reduction in bacterial counts at 24 hr post-infection and improved survival rates. These observations shed new light on the virulence mechanisms of Y. pestis during pneumonic plague, and have implications for the development of novel

  8. TLR2-induced IL-10 production impairs neutrophil recruitment to infected tissues during neonatal bacterial sepsis.

    PubMed

    Andrade, Elva B; Alves, Joana; Madureira, Pedro; Oliveira, Liliana; Ribeiro, Adília; Cordeiro-da-Silva, Anabela; Correia-Neves, Margarida; Trieu-Cuot, Patrick; Ferreira, Paula

    2013-11-01

    Sepsis is the third most common cause of neonatal death, with Group B Streptococcus (GBS) being the leading bacterial agent. The pathogenesis of neonatal septicemia is still unsolved. We described previously that host susceptibility to GBS infection is due to early IL-10 production. In this study, we investigated whether triggering TLR2 to produce IL-10 is a risk factor for neonatal bacterial sepsis. We observed that, in contrast to wild-type (WT) pups, neonatal TLR2-deficient mice were resistant to GBS-induced sepsis. Moreover, if IL-10 signaling were blocked in WT mice, they also were resistant to sepsis. This increased survival rate was due to an efficient recruitment of neutrophils to infected tissues that leads to bacterial clearance, thus preventing the development of sepsis. To confirm that IL-10 produced through TLR2 activation prevents neutrophil recruitment, WT pups were treated with the TLR2 agonist Pam3CSK4 prior to nebulization with the neutrophil chemotactic agent LTB4. Neutrophil recruitment into the neonatal lungs was inhibited in pups treated with Pam3CSK4. However, the migration was restored in Pam3CSK4-treated pups when IL-10 signaling was blocked (either by anti-IL-10R mAb treatment or by using IL-10-deficient mice). Our findings highlight that TLR2-induced IL-10 production is a key event in neonatal susceptibility to bacterial sepsis. PMID:24078699

  9. Annexin A1 and the Resolution of Inflammation: Modulation of Neutrophil Recruitment, Apoptosis, and Clearance

    PubMed Central

    Sugimoto, Michelle Amantéa; Vago, Juliana Priscila; Teixeira, Mauro Martins; Sousa, Lirlândia Pires

    2016-01-01

    Neutrophils (also named polymorphonuclear leukocytes or PMN) are essential components of the immune system, rapidly recruited to sites of inflammation, providing the first line of defense against invading pathogens. Since neutrophils can also cause tissue damage, their fine-tuned regulation at the inflammatory site is required for proper resolution of inflammation. Annexin A1 (AnxA1), also known as lipocortin-1, is an endogenous glucocorticoid-regulated protein, which is able to counterregulate the inflammatory events restoring homeostasis. AnxA1 and its mimetic peptides inhibit neutrophil tissue accumulation by reducing leukocyte infiltration and activating neutrophil apoptosis. AnxA1 also promotes monocyte recruitment and clearance of apoptotic leukocytes by macrophages. More recently, some evidence has suggested the ability of AnxA1 to induce macrophage reprogramming toward a resolving phenotype, resulting in reduced production of proinflammatory cytokines and increased release of immunosuppressive and proresolving molecules. The combination of these mechanisms results in an effective resolution of inflammation, pointing to AnxA1 as a promising tool for the development of new therapeutic strategies to treat inflammatory diseases. PMID:26885535

  10. The time-of-day of myocardial infarction onset affects healing through oscillations in cardiac neutrophil recruitment.

    PubMed

    Schloss, Maximilian J; Horckmans, Michael; Nitz, Katrin; Duchene, Johan; Drechsler, Maik; Bidzhekov, Kiril; Scheiermann, Christoph; Weber, Christian; Soehnlein, Oliver; Steffens, Sabine

    2016-01-01

    Myocardial infarction (MI) is the leading cause of death in Western countries. Epidemiological studies show acute MI to be more prevalent in the morning and to be associated with a poorer outcome in terms of mortality and recovery. The mechanisms behind this association are not fully understood. Here, we report that circadian oscillations of neutrophil recruitment to the heart determine infarct size, healing, and cardiac function after MI Preferential cardiac neutrophil recruitment during the active phase (Zeitgeber time, ZT13) was paralleled by enhanced myeloid progenitor production, increased circulating numbers of CXCR2(hi) neutrophils as well as upregulated cardiac adhesion molecule and chemokine expression. MI at ZT13 resulted in significantly higher cardiac neutrophil infiltration compared to ZT5, which was inhibited by CXCR2 antagonism or neutrophil-specific CXCR2 knockout. Limiting exaggerated neutrophilic inflammation at this time point significantly reduced the infarct size and improved cardiac function. PMID:27226028

  11. Nicorandil inhibits neutrophil recruitment in carrageenan-induced experimental pleurisy in mice.

    PubMed

    Matsui, Tamires C; Coura, Giovanna M E; Melo, Ivo S F; Batista, Carla R A; Augusto, Paulo Sérgio A; Godin, Adriana M; Araújo, Débora P; César, Isabela C; Ribeiro, Lucas S; Souza, Danielle G; Klein, André; de Fátima, Ângelo; Machado, Renes R; Coelho, Márcio M

    2015-12-15

    Nicorandil is a drug characterized by the coupling of a nitric oxide (NO) donor to nicotinamide. We have previously demonstrated that nicotinamide exhibits activity in different models of pain and inflammation. Now, we investigated the effects induced by per os (p.o.) administration of nicorandil (25, 50 or 100mg/Kg) on neutrophil recruitment in a carrageenan-induced model of pleurisy in mice. Effects induced by nicorandil (100mg/kg) were compared with those induced by equimolar doses of nicotinamide (58mg/kg) and N-(2-hydroxyethyl)-nicotinamide (NHN; 79mg/kg). We also investigated whether effects on the production of inflammatory mediators play a role in the activity of nicorandil. P.o. nicorandil, 0.5h before and 1h after the i.pl. injection of carrageenan, reduced neutrophil recruitment. However, equimolar doses of nicotinamide or NHN failed to induce such effect. Single treatment (previous or late) with nicorandil (100mg/Kg, p.o.) also reduced neutrophils recruitment, although to a lesser extent when compared to the double treatment. Nicorandil reduced the concentrations of interleukin-1β, CXCL-1 and prostaglandin E2 in the pleural exudate. Concluding, we demonstrated the activity of nicorandil in a model of pleurisy induced by carrageenan. This activity was characterized by reduction of the neutrophil accumulation and inhibition of production of inflammatory mediators. The effects induced by nicorandil on the leukocytes recruitment and production of inflammatory mediators contribute to a better understanding of its clinical benefits and indicate that these benefits may be due to its vasodilating and anti-inflammatory activities. PMID:26607465

  12. Tumor-Recruited Neutrophils and Neutrophil TIMP-Free MMP-9 Regulate Coordinately the Levels of Tumor Angiogenesis and Efficiency of Malignant Cell Intravasation

    PubMed Central

    Bekes, Erin M.; Schweighofer, Bernhard; Kupriyanova, Tatyana A.; Zajac, Ewa; Ardi, Veronica C.; Quigley, James P.; Deryugina, Elena I.

    2011-01-01

    Tumor-associated neutrophils contribute to neovascularization by supplying matrix metalloproteinase-9 (MMP-9), a protease that has been genetically and biochemically linked to induction of angiogenesis. Specific roles of inflammatory neutrophils and their distinct proMMP-9 in the coordinate regulation of tumor angiogenesis and tumor cell dissemination, however, have not been addressed. We demonstrate that the primary tumors formed by highly disseminating variants of human fibrosarcoma and prostate carcinoma recruit elevated levels of infiltrating MMP-9-positive neutrophils and concomitantly exhibit enhanced levels of angiogenesis and intravasation. Specific inhibition of neutrophil influx by interleukin 8 (IL-8) neutralization resulted in the coordinated diminishment of tumor angiogenesis and intravasation, both of which were rescued by purified neutrophil proMMP-9. However, if neutrophil proMMP-9, naturally devoid of tissue inhibitor of metalloproteinases (TIMP), was delivered in complex with TIMP-1 or in a mixture with TIMP-2, the protease failed to rescue the inhibitory effects of anti-IL8 therapy, indicating that the TIMP-free status of proMMP-9 is critical for facilitating tumor angiogenesis and intravasation. Our findings directly link tumor-associated neutrophils and their TIMP-free proMMP-9 with the ability of aggressive tumor cells to induce the formation of new blood vessels that serve as conduits for tumor cell dissemination. Thus, treatment of cancers associated with neutrophil infiltration may benefit from specific targeting of neutrophil MMP-9 at early stages to prevent ensuing tumor angiogenesis and tumor metastasis. PMID:21741942

  13. Platelet-Derived CCL5 Regulates CXC Chemokine Formation and Neutrophil Recruitment in Acute Experimental Colitis.

    PubMed

    Yu, Changhui; Zhang, Songen; Wang, Yongzhi; Zhang, Su; Luo, Lingtao; Thorlacius, Henrik

    2016-02-01

    Accumulating data suggest that platelets not only regulate thrombosis and haemostasis but also inflammatory processes. Platelets contain numerous potent pro-inflammatory compounds, including the chemokines CCL5 and CXCL4, although their role in acute colitis remains elusive. The aim of this study is to examine the role of platelets and platelet-derived chemokines in acute colitis. Acute colitis is induced in female Balb/c mice by administration of 5% dextran sodium sulfate (DSS) for 5 days. Animals receive a platelet-depleting, anti-CCL5, anti-CXCL4, or a control antibody prior to DSS challenge. Colonic tissue is collected for quantification of myeloperoxidase (MPO) activity, CXCL5, CXCL2, interleukin-6 (IL-6), and CCL5 levels as well as morphological analyses. Platelet depletion reduce tissue damage and clinical disease activity index in DSS-exposed animals. Platelet depletion not only reduces levels of CXCL2 and CXCL5 but also levels of CCL5 in the inflamed colon. Immunoneutralization of CCL5 but not CXCL4 reduces tissue damage, CXC chemokine expression, and neutrophil recruitment in DSS-treated animals. These findings show that platelets play a key role in acute colitis by regulating CXC chemokine generation, neutrophil infiltration, and tissue damage in the colon. Moreover, our results suggest that platelet-derived CCL5 is an important link between platelet activation and neutrophil recruitment in acute colitis. PMID:26089223

  14. Aryl Hydrocarbon Receptor Targets Pathways Extrinsic to Bone Marrow Cells to Enhance Neutrophil Recruitment during Influenza Virus Infection

    PubMed Central

    Teske, Sabine; Bohn, Andrea A.; Hogaboam, Jason P.; Lawrence, B. Paige

    2010-01-01

    There is growing evidence that neutrophils influence host resistance during influenza virus infection; however, factors that regulate neutrophil migration to the lung during viral infection are unclear. Activation of the aryl hydrocarbon receptor (AhR) by the pollutant 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD or dioxin) results in an increased number of neutrophils in the lung after influenza virus infection. The mechanism of AhR-mediated neutrophilia does not involve elevated levels of soluble neutrophil chemoattractants, upregulated adhesion molecules on pulmonary neutrophils, delayed neutrophil apoptosis, or increased vascular damage. In this study, we determined whether AhR activation increases neutrophil numbers systemically or only in the infected lung, and whether AhR-regulated events within the hematopoietic system underlie the dioxin-induced increase in pulmonary neutrophils observed during influenza virus infection. We report here that AhR activation does not increase neutrophil numbers systemically or increase neutrophil production in hematopoietic tissue, suggesting that the elevated number of neutrophils is restricted to the site of antigen challenge. The generation of CD45.2AhR−/− → CD45.1AhR+/+ bone marrow chimeric mice demonstrates that even when hematopoietic cells lack the AhR, TCDD treatment still results in twice as many pulmonary neutrophils compared with control-treated, infected CD45.2AhR−/− → CD45.1AhR+/+ chimeric mice. This finding reveals that AhR-mediated events extrinsic to bone marrow–derived cells affect the directional migration of neutrophils to the infected lung. These results suggest that the lung contains important and heretofore overlooked targets of AhR regulation, unveiling a novel mechanism for controlling neutrophil recruitment to the infected lung. PMID:18007012

  15. The atypical cannabinoid O-1602 protects against experimental colitis and inhibits neutrophil recruitment

    PubMed Central

    Schicho, Rudolf; Bashashati, Mohammad; Bawa, Misha; McHugh, Douglas; Saur, Dieter; Hu, Huang-Ming; Zimmer, Andreas; Lutz, Beat; Mackie, Ken; Bradshaw, Heather B.; McCafferty, Donna-Marie; Sharkey, Keith A.; Storr, Martin

    2010-01-01

    Background Cannabinoids are known to reduce intestinal inflammation. Atypical cannabinoids produce pharmacological effects via unidentified targets. We were interested whether the atypical cannabinoid O-1602, reportedly an agonist of the putative cannabinoid receptor GPR55, reduces disease severity of dextran sulfate sodium (DSS) and trinitrobenzene sulfonic acid (TNBS)-induced colitis in C57BL/6N and CD1 mice. Methods DSS (2.5% and 4%) was supplied in drinking water for one week while TNBS (4 mg) was applied as a single intrarectal bolus. Results Both treatments caused severe colitis. Injection of O-1602 (5 mg/kg i.p.) significantly reduced macroscopic and histological colitis scores, and myeloperoxidase activity. The protective effect was still present in cannabinoid receptor 1 (CB1) and 2 (CB2) double knockout mice and mice lacking the GPR55 gene. To investigate a potential mechanism underlying the protection by O-1602 we performed neutrophil chemotactic assays. O-1602 concentration-dependently inhibited migration of murine neutrophils to keratinocyte-derived chemokine (KC), N-formyl-methionyl-leucyl-phenylalanine (fMLP) and the N-formyl-peptide receptor ligand WKYMVm. The inhibitory effect of O-1602 was preserved in neutrophils from CB1/CB2 double knockout and GPR55 knockout mice. No differences were seen in locomotor activity between O-1602-treated and control mice indicating lack of central sedation by this compound. Conclusions Our data demonstrate that O-1602 is protective against experimentally induced colitis and inhibits neutrophil recruitment independently of CB1, CB2 and GPR55 receptors. Thus, atypical cannabinoids represent a novel class of therapeutics that may be useful for the treatment of inflammatory bowel diseases. PMID:21744421

  16. Group A Streptococcus Secreted Esterase Hydrolyzes Platelet-Activating Factor to Impede Neutrophil Recruitment and Facilitate Innate Immune Evasion

    PubMed Central

    Li, Jinquan; Garcia, Cristiana C.; Feng, Wenchao; Kirpotina, Liliya N.; Hilmer, Jonathan; Tavares, Luciana P.; Layton, Arthur W.; Quinn, Mark T.; Bothner, Brian; Teixeira, Mauro M.; Lei, Benfang

    2012-01-01

    The innate immune system is the first line of host defense against invading organisms. Thus, pathogens have developed virulence mechanisms to evade the innate immune system. Here, we report a novel means for inhibition of neutrophil recruitment by Group A Streptococcus (GAS). Deletion of the secreted esterase gene (designated sse) in M1T1 GAS strains with (MGAS5005) and without (MGAS2221) a null covS mutation enhances neutrophil ingress to infection sites in the skin of mice. In trans expression of SsE in MGAS2221 reduces neutrophil recruitment and enhances skin invasion. The sse deletion mutant of MGAS5005 (ΔsseMGAS5005) is more efficiently cleared from skin than the parent strain. SsE hydrolyzes the sn-2 ester bond of platelet-activating factor (PAF), converting biologically active PAF into inactive lyso-PAF. KM and kcat of SsE for hydrolysis of 2-thio-PAF were similar to those of the human plasma PAF acetylhydrolase. Treatment of PAF with SsE abolishes the capacity of PAF to induce activation and chemotaxis of human neutrophils. More importantly, PAF receptor-deficient mice significantly reduce neutrophil infiltration to the site of ΔsseMGAS5005 infection. These findings identify the first secreted PAF acetylhydrolase of bacterial pathogens and support a novel GAS evasion mechanism that reduces phagocyte recruitment to sites of infection by inactivating PAF, providing a new paradigm for bacterial evasion of neutrophil responses. PMID:22496650

  17. The LPS-induced neutrophil recruitment into rat air pouches is mediated by TNFα: likely macrophage origin

    PubMed Central

    Arreto, C-D.; Dumarey, C.; Nahori, M-A.; Vargaftig, B. B.

    1997-01-01

    The role of resident cells during the lipopolysaccharide (LPS)-induced neutrophil recruitment into rat air pouches was investigated. In this model, LPS (Escherichia coli, O55: B5 strain; 2–2000 ng) induced a dose– and time-dependent neutrophil recruitment accompanied by the generation of a tumour necrosis factor-α (TNFα)-like activity. Dexamethasone (0.05–5 mug) and cycloheximide (6 ng), injected 2 h before LPS into the pouches, inhibited the neutrophil recruitment and the generation of the TNFα-like activity, while the H1-receptor antagonist mepyramine (1 and 4 mg/kg, i.p., 0.5 h before LPS) and the PAF-receptor antagonist WEB 2170 (0.05 and 1 mg/kg, i.p., 0.5 h before LPS) had no effect. Purified alveolar macrophages (AM) were used to replenish the pouches of cycloheximide-treated recipient rats. AM provided by PBS-treated animals led to the recovery of the LPS-induced neutrophil recruitment and of the TNFα-like formation contrasting with those from cycloheximide-treated animals (1 mg/kg, i.p.). When delivered in situ, liposome-encapsulated clodronate, a macrophage depletor, significantly impaired both the LPSinduced neutrophil recruitment and the TNFα-like activity. An anti-murine TNFα polyclonal antibody (0.5 h before LPS) was also effective. These results emphasize the pivotal role of macrophages for LPS-induced neutrophil recruitment via the formation of TNFα. PMID:18472868

  18. Pharmacological Beta-Adrenergic Receptor Activation Attenuates Neutrophil Recruitment by a Mechanism Dependent on Nicotinic Receptor and the Spleen.

    PubMed

    Silva, Rangel L; Castanheira, Fernanda V; Figueiredo, Jozi G; Bassi, Gabriel S; Ferreira, Sérgio H; Cunha, Fernando Q; Cunha, Thiago M; Kanashiro, Alexandre

    2016-08-01

    The aim of this study was to identify the effect of beta-adrenergic receptor activation on neutrophil migration in experimental peritonitis elucidating the neuroimmune components involved such as nicotinic receptors and the spleen. Mice pre-treated with mecamylamine (nicotinic antagonist) and propranolol (beta-adrenergic antagonist) or splenectomized animals were treated with isoproterenol (beta-adrenergic agonist) prior to intraperitoneal injection of carrageenan. After 4 h, the infiltrating neutrophils and the local cytokine/chemokine levels were evaluated in the peritoneal lavage. The effect of isoproterenol on neutrophil chemotaxis was investigated in a Boyden chamber. Isoproterenol inhibited neutrophil trafficking, reducing the cytokine/chemokine release and neutrophil chemotaxis. Surprisingly, the isoproterenol effect on neutrophil migration was totally reverted by splenectomy and mecamylamine pre-treatment. In contrast, the inhibitory effect of nicotine on neutrophil migration was abrogated only by splenectomy but not by propranolol pre-treatment. Collectively, our data show that beta-adrenergic receptor activation regulates the acute neutrophil recruitment via splenic nicotinic receptor. PMID:27262431

  19. Toll-Like Receptor 9 Signaling in Dendritic Cells Regulates Neutrophil Recruitment to Inflammatory Foci following Leishmania infantum Infection

    PubMed Central

    Sacramento, Laís; Trevelin, Silvia C.; Nascimento, Manuela S.; Lima-Jùnior, Djalma S.; Costa, Diego L.; Almeida, Roque P.; Cunha, Fernando Q.

    2015-01-01

    Leishmania infantum is a protozoan parasite that causes visceral leishmaniasis (VL). This infection triggers dendritic cell (DC) activation through the recognition of microbial products by Toll-like receptors (TLRs). Among the TLRs, TLR9 is required for DC activation by different Leishmania species. We demonstrated that TLR9 is upregulated in vitro and in vivo during infection. We show that C57BL/6 mice deficient in TLR9 expression (TLR9−/− mice) are more susceptible to infection and display higher parasite numbers in the spleen and liver. The increased susceptibility of TLR9−/− mice was due to the impaired recruitment of neutrophils to the infection foci associated with reduced levels of neutrophil chemoattractants released by DCs in the target organs. Moreover, both Th1 and Th17 cells were also committed in TLR9−/− mice. TLR9-dependent neutrophil recruitment is mediated via the MyD88 signaling pathway but is TIR domain-containing adapter-inducing interferon beta (TRIF) independent. Furthermore, L. infantum failed to activate both plasmacytoid and myeloid DCs from TLR9−/− mice, which presented reduced surface costimulatory molecule expression and chemokine release. Interestingly, neutrophil chemotaxis was affected both in vitro and in vivo when DCs were derived from TLR9−/− mice. Our results suggest that TLR9 plays a critical role in neutrophil recruitment during the protective response against L. infantum infection that could be associated with DC activation. PMID:26371124

  20. Treadmill Exercise Induces Neutrophil Recruitment into Muscle Tissue in a Reactive Oxygen Species-Dependent Manner. An Intravital Microscopy Study

    PubMed Central

    Nunes-Silva, Albená; Bernardes, Priscila T. T.; Rezende, Bárbara M.; Lopes, Fernando; Gomes, Elisa C.; Marques, Pedro E.; Lima, Paulo M. A.; Coimbra, Cândido C.; Menezes, Gustavo B.; Teixeira, Mauro M.; Pinho, Vanessa

    2014-01-01

    Intense exercise is a physiological stress capable of inducing the interaction of neutrophils with muscle endothelial cells and their transmigration into tissue. Mechanisms driving this physiological inflammatory response are not known. Here, we investigate whether production of reactive oxygen species is relevant for neutrophil interaction with endothelial cells and recruitment into the quadriceps muscle in mice subjected to the treadmill fatiguing exercise protocol. Mice exercised until fatigue by running for 56.3±6.8 min on an electric treadmill. Skeletal muscle was evaluated by intravital microscopy at different time points after exercise, and then removed to assess local oxidative stress and histopathological analysis. We observed an increase in plasma lactate and creatine kinase (CK) concentrations after exercise. The numbers of monocytes, neutrophils, and lymphocytes in blood increased 12 and 24 hours after the exercise. Numbers of rolling and adherent leukocytes increased 3, 6, 12, and 24 hours post-exercise, as assessed by intravital microscopy. Using LysM-eGFP mice and confocal intravital microscopy technology, we show that the number of transmigrating neutrophils increased 12 hours post-exercise. Mutant gp91phox-/- (non-functional NADPH oxidase) mice and mice treated with apocynin showed diminished neutrophil recruitment. SOD treatment promoted further adhesion and transmigration of leukocytes 12 hours after the exercise. These findings confirm our hypothesis that treadmill exercise increases the recruitment of leukocytes to the postcapillary venules, and NADPH oxidase-induced ROS plays an important role in this process. PMID:24798414

  1. Stromal cells differentially regulate neutrophil and lymphocyte recruitment through the endothelium

    PubMed Central

    McGettrick, Helen M; Buckley, Christopher D; Filer, Andrew; Ed Rainger, G; Nash, Gerard B

    2010-01-01

    Stromal fibroblasts modify the initial recruitment of leucocytes by endothelial cells (EC), but their effects on subsequent transendothelial migration remain unclear. Here, EC and dermal or synovial fibroblasts were cultured on opposite surfaces of 3-μm pore filters and incorporated in static or flow-based migration assays. Fibroblasts had little effect on tumour necrosis factor-α-induced transendothelial migration of neutrophils, but tended to increase the efficiency of migration away from the endothelium. Surprisingly, similar close contact between EC and fibroblasts strongly reduced lymphocyte migration in static assays, and nearly abolished stable lymphocyte adhesion from flow. Fibroblasts did not alter endothelial surface expression of adhesion molecules or messenger RNA for chemokines. Inhibition of attachment did not occur when EC-fibroblast contact was restricted by using 0·4-μm pore filters, but under these conditions pre-treatment with heparinase partially inhibited adhesion. In the 3-μm pore co-cultures, inhibition of metalloproteinase activity partially recovered lymphocyte adhesion, but addition of CXCL12 (SDF-1α) to the endothelial surface did not. Hence, the ability of EC to present activating chemokines for lymphocytes may have been enzymatically inhibited by direct contact with fibroblasts. To avoid contact, we cultured EC and fibroblasts on separate 3-μm pore filters one above the other. Here, fibroblasts promoted the transendothelial migration of lymphocytes. Fibroblasts generate CXCL12, but blockade of CXCL12 receptor had no effect on lymphocyte migration. While stromal cells can provide signal(s) promoting leucocyte migration away from the sub-endothelial space, direct cell contact (which might occur in damaged tissue) may cause disruption of chemokine signalling, specifically inhibiting lymphocyte rather than neutrophil recruitment. PMID:20518822

  2. Pulmonary leukostasis and the inhibition of airway neutrophil recruitment are early events in the endotoxemic rat.

    PubMed

    Wagner, James G; Harkema, Jack R; Roth, Robert A

    2002-02-01

    Neutrophil (polymorphonuclear leukocyte [PMN]) migration into pulmonary airspaces is a prerequisite for clearance of bacteria commonly found in nosocomial pneumonia. Patients at risk for nosocomial pneumonia often experience endotoxemia, and neutrophil dysfunction is associated with endotoxemia in both humans and animals. Using a rodent model of endotoxemia-associated pneumonia, we characterized the altered kinetics of pulmonary PMN trafficking and addressed the roles of platelets, tumor necrosis factor (TNF), and products of complement activation as potential mediators in the modulation of PMN migratory function. In male Sprague-Dawley rats made endotoxemic with intravenously (i.v.) administered endotoxin (lipopolysaccharide [LPS]), recruitment of PMNs into the lung airspaces in response to intratracheally (i.t.) instilled LPS was inhibited. In animals given IT LPS alone (0.5 mg/rat), numbers of airway PMNs were significantly elevated by 2 h, and immunohistochemical evaluation revealed PMNs in alveolar airspaces, alveolar walls, and in interstitium surrounding large airways. LPS (2 mg/kg i.v.) caused neutropenia and pulmonary PMN sequestration within 15 min of administration. Inhibition of airway PMN accumulation occurred by 30 min and lasted for at least 6 h after i.v. LPS. Factors present or activated after 30 min of endotoxemia were hypothesized to mediate the inhibitory effect of i.v. LPS. We found that pretreatment of rats with cobra venom factor to deplete complement (and C5a production) or immunodepletion of platelets or TNF did not affect the ability of i.v. LPS to inhibit pulmonary PMN recruitment or to cause pulmonary leukostasis. In summary, our results show that the inhibitory effects of i.v. LPS on PMN trafficking are rapid and persist for several hours and suggest that neither TNF, C5a, nor platelets are sufficient to mediate the inhibitory response. PMID:11837792

  3. Macrophage-derived neutrophil chemotactic factor is involved in the neutrophil recruitment inhibitory activity present in the supernatants of LPS-stimulated macrophages

    PubMed Central

    Tavares-Murta, B. M.; Cunha, F. Q.; Dias-Baruffi, M.; Roque-Barreira, M. C.

    1996-01-01

    In a previous study, we demonstrated the presence of a neutrophil recruitment inhibitory factor (NRIF) in the supernatants of LPS-stimulated macrophages. Recently, the purification of a 54 kDa protein, identified as the macrophage-derived neutrophil chemotactic factor (MNCF) was reported. Since NRIF and MNCF are obtained under the same conditions, and, since the intravenous administration of TNF-α and IL-8 inhibits neutrophil migration, we have investigated whether MNCF could be responsible for this inhibitory activity. After affinity chromatography of the macrophage supernatants on a D-galactose column, the inhibitory activity was recovered in both the unbound (D-gal−) and bound (D-gal+) fractions, with MNCF being found in the D-gal+ fraction. Further gel filtration of the latter on Superdex 75 yielded a single peak containing both activities. In a cytotoxicity assay, most of the TNF found in the crude supernatants was recovered in the D-gal− fraction. Furthermore, the incubation of the D-gal− fraction with anti-TNF-α plus anti-IL-8 antisera partially prevents its inhibitory effect on neutrophil migration, but had no effect on the D-gal+ activity. Overall, these results suggest that the D-gal− inhibitory effect is partially mediated by TNF-α and IL-8, and that MNCF accounts for the inhibition of neutrophil migration in vivo by the D-gal+ fraction. PMID:18475709

  4. Neutrophil Recruitment and Activation in Decidua with Intra-Amniotic IL-1beta in the Preterm Rhesus Macaque1

    PubMed Central

    Presicce, Pietro; Senthamaraikannan, Paranthaman; Alvarez, Manuel; Rueda, Cesar M.; Cappelletti, Monica; Miller, Lisa A.; Jobe, Alan H.; Chougnet, Claire A.; Kallapur, Suhas G.

    2014-01-01

    ABSTRACT Chorioamnionitis, an infection/inflammation of the fetomaternal membranes, is frequently associated with preterm delivery. The mechanisms of inflammation in chorioamnionitis are poorly understood. We hypothesized that neutrophils recruited to the decidua would be the major producers of proinflammatory cytokines. We injected intra-amniotic (IA) interleukin 1beta (IL-1beta) at ∼80% gestation in rhesus macaque monkeys, Macaca mulatta, delivered the fetuses surgically 24 h or 72 h after IA injections, and investigated the role of immune cells in the chorion-amnion decidua. IA IL-1beta induced a robust infiltration of neutrophils and significant increases of proinflammatory cytokines in the chorioamnion decidua at 24 h after exposure, with a subsequent decrease at 72 h. Neutrophils in the decidua were the major source of tumor necrosis factor alpha (TNFalpha) and IL-8. Interestingly, IA IL-1beta also induced a significant increase in anti-inflammatory indoleamine 2,3-dioxygenase (IDO) expression in the decidua neutrophils. The frequency of regulatory T cells (Tregs) and FOXP3 mRNA expression in the decidua did not change after IA IL-1beta injection. Collectively, our data demonstrate that in this model of sterile chorioamnionitis, the decidua neutrophils cause the inflammation in the gestational tissues but may also act as regulators to dampen the inflammation. These results help to understand the contribution of neutrophils to the pathogenesis of chorioamnionitis-induced preterm labor. PMID:25537373

  5. Targeting distinct tautomerase sites of D-DT and MIF with a single molecule for inhibition of neutrophil lung recruitment

    PubMed Central

    Rajasekaran, Deepa; Zierow, Swen; Syed, Mansoor; Bucala, Richard; Bhandari, Vineet; Lolis, Elias J.

    2014-01-01

    We report a new inflammatory activity for extracellular d-dopachrome tautomerase (D-DT), the recruitment of neutrophils to the lung on D-DT intratracheal installation of C57BL/6J mice with an EC50 of 5.6 μg. We also find that D-DT and macrophage migration inhibitory factor (MIF) have additive effects in neutrophil recruitment. Although the tautomerase site of D-DT and its homologue MIF are biophysically very different, 4-iodo-6-phenylpyrimidine (4-IPP) forms a covalent bond with Pro-1 of both proteins, resulting in a 6-phenylpyrimidine (6-PP) adduct. Recruitment of neutrophils to the lung for the 6-PP adducts of D-DT and MIF are reduced by ∼50% relative to the apo proteins, demonstrating that an unmodified Pro-1 is important for this activity, but there is no cooperativity in inhibition of the proteins together. The differences in the binding mode of the 6-PP adduct for D-DT was determined by crystallographic studies at 1.13 Å resolution and compared to the structure of the MIF–6-PP complex. There are major differences in the location of the 6-PP adduct to the D-DT and MIF active sites that provide insight into the lack of cooperativity by 4-IPP and into tuning the properties of the covalent inhibitors of D-DT and MIF that are necessary for the development of therapeutic small molecules against neutrophil damage from lung infections such as Pseudomonas aeruginosa in cystic fibrosis and immunocompromised patients.—Rajasekaran, D., Zierow, S., Syed, M., Bucala, R., Bhandari, V., Lolis, E. J. Targeting distinct tautomerase sites of D-DT and MIF with a single molecule for inhibition of neutrophil lung recruitment. PMID:25016026

  6. Tir Triggers Expression of CXCL1 in Enterocytes and Neutrophil Recruitment during Citrobacter rodentium Infection.

    PubMed

    Crepin, Valerie F; Habibzay, Maryam; Glegola-Madejska, Izabela; Guenot, Marianne; Collins, James W; Frankel, Gad

    2015-09-01

    The hallmarks of enteropathogenic Escherichia coli (EPEC) infection are formation of attaching and effacing (A/E) lesions on mucosal surfaces and actin-rich pedestals on cultured cells, both of which are dependent on the type III secretion system effector Tir. Following translocation into cultured cells and clustering by intimin, Tir Y474 is phosphorylated, leading to recruitment of Nck, activation of N-WASP, and actin polymerization via the Arp2/3 complex. A secondary, weak, actin polymerization pathway is triggered via an NPY motif (Y454). Importantly, Y454 and Y474 play no role in A/E lesion formation on mucosal surfaces following infection with the EPEC-like mouse pathogen Citrobacter rodentium. In this study, we investigated the roles of Tir segments located upstream of Y451 and downstream of Y471 in C. rodentium colonization and A/E lesion formation. We also tested the role that Tir residues Y451 and Y471 play in host immune responses to C. rodentium infection. We found that deletion of amino acids 382 to 462 or 478 to 547 had no impact on the ability of Tir to mediate A/E lesion formation, although deletion of amino acids 478 to 547 affected Tir translocation. Examination of enterocytes isolated from infected mice revealed that a C. rodentium strain expressing Tir_Y451A/Y471A recruited significantly fewer neutrophils to the colon and triggered less colonic hyperplasia on day 14 postinfection than the wild-type strain. Consistently, enterocytes isolated from mice infected with C. rodentium expressing Tir_Y451A/Y471A expressed significantly less CXCL1. These result show that Tir-induced actin remodeling plays a direct role in modulation of immune responses to C. rodentium infection. PMID:26077760

  7. Tir Triggers Expression of CXCL1 in Enterocytes and Neutrophil Recruitment during Citrobacter rodentium Infection

    PubMed Central

    Habibzay, Maryam; Glegola-Madejska, Izabela; Guenot, Marianne; Collins, James W.

    2015-01-01

    The hallmarks of enteropathogenic Escherichia coli (EPEC) infection are formation of attaching and effacing (A/E) lesions on mucosal surfaces and actin-rich pedestals on cultured cells, both of which are dependent on the type III secretion system effector Tir. Following translocation into cultured cells and clustering by intimin, Tir Y474 is phosphorylated, leading to recruitment of Nck, activation of N-WASP, and actin polymerization via the Arp2/3 complex. A secondary, weak, actin polymerization pathway is triggered via an NPY motif (Y454). Importantly, Y454 and Y474 play no role in A/E lesion formation on mucosal surfaces following infection with the EPEC-like mouse pathogen Citrobacter rodentium. In this study, we investigated the roles of Tir segments located upstream of Y451 and downstream of Y471 in C. rodentium colonization and A/E lesion formation. We also tested the role that Tir residues Y451 and Y471 play in host immune responses to C. rodentium infection. We found that deletion of amino acids 382 to 462 or 478 to 547 had no impact on the ability of Tir to mediate A/E lesion formation, although deletion of amino acids 478 to 547 affected Tir translocation. Examination of enterocytes isolated from infected mice revealed that a C. rodentium strain expressing Tir_Y451A/Y471A recruited significantly fewer neutrophils to the colon and triggered less colonic hyperplasia on day 14 postinfection than the wild-type strain. Consistently, enterocytes isolated from mice infected with C. rodentium expressing Tir_Y451A/Y471A expressed significantly less CXCL1. These result show that Tir-induced actin remodeling plays a direct role in modulation of immune responses to C. rodentium infection. PMID:26077760

  8. Tumor Exosomal RNAs Promote Lung Pre-metastatic Niche Formation by Activating Alveolar Epithelial TLR3 to Recruit Neutrophils.

    PubMed

    Liu, Yanfang; Gu, Yan; Han, Yanmei; Zhang, Qian; Jiang, Zhengping; Zhang, Xiang; Huang, Bo; Xu, Xiaoqing; Zheng, Jianming; Cao, Xuetao

    2016-08-01

    The pre-metastatic niche educated by primary tumor-derived elements contributes to cancer metastasis. However, the role of host stromal cells in metastatic niche formation and organ-specific metastatic tropism is not clearly defined. Here, we demonstrate that lung epithelial cells are critical for initiating neutrophil recruitment and lung metastatic niche formation by sensing tumor exosomal RNAs via Toll-like receptor 3 (TLR3). TLR3-deficient mice show reduced lung metastasis in the spontaneous metastatic models. Mechanistically, primary tumor-derived exosomal RNAs, which are enriched in small nuclear RNAs, activate TLR3 in lung epithelial cells, consequently inducing chemokine secretion in the lung and promoting neutrophil recruitment. Identification of metastatic axis of tumor exosomal RNAs and host lung epithelial cell TLR3 activation provides potential targets to control cancer metastasis to the lung. PMID:27505671

  9. Optineurin deficiency in mice contributes to impaired cytokine secretion and neutrophil recruitment in bacteria-driven colitis.

    PubMed

    Chew, Thean S; O'Shea, Nuala R; Sewell, Gavin W; Oehlers, Stefan H; Mulvey, Claire M; Crosier, Philip S; Godovac-Zimmermann, Jasminka; Bloom, Stuart L; Smith, Andrew M; Segal, Anthony W

    2015-08-01

    Crohn's disease (CD) is associated with delayed neutrophil recruitment and bacterial clearance at sites of acute inflammation as a result of impaired secretion of proinflammatory cytokines by macrophages. To investigate the impaired cytokine secretion and confirm our previous findings, we performed transcriptomic analysis in macrophages and identified a subgroup of individuals with CD who had low expression of the autophagy receptor optineurin (OPTN). We then clarified the role of OPTN deficiency in: macrophage cytokine secretion; mouse models of bacteria-driven colitis and peritonitis; and zebrafish Salmonella infection. OPTN-deficient bone-marrow-derived macrophages (BMDMs) stimulated with heat-killed Escherichia coli secreted less proinflammatory TNFα and IL6 cytokines despite similar gene transcription, which normalised with lysosomal and autophagy inhibitors, suggesting that TNFα is mis-trafficked to lysosomes via bafilomycin-A-dependent pathways in the absence of OPTN. OPTN-deficient mice were more susceptible to Citrobacter colitis and E. coli peritonitis, and showed reduced levels of proinflammatory TNFα in serum, diminished neutrophil recruitment to sites of acute inflammation and greater mortality, compared with wild-type mice. Optn-knockdown zebrafish infected with Salmonella also had higher mortality. OPTN plays a role in acute inflammation and neutrophil recruitment, potentially via defective macrophage proinflammatory cytokine secretion, which suggests that diminished OPTN expression in humans might increase the risk of developing CD. PMID:26044960

  10. Optineurin deficiency in mice contributes to impaired cytokine secretion and neutrophil recruitment in bacteria-driven colitis

    PubMed Central

    Chew, Thean S.; O'Shea, Nuala R.; Sewell, Gavin W.; Oehlers, Stefan H.; Mulvey, Claire M.; Crosier, Philip S.; Godovac-Zimmermann, Jasminka; Bloom, Stuart L.; Smith, Andrew M.; Segal, Anthony W.

    2015-01-01

    ABSTRACT Crohn's disease (CD) is associated with delayed neutrophil recruitment and bacterial clearance at sites of acute inflammation as a result of impaired secretion of proinflammatory cytokines by macrophages. To investigate the impaired cytokine secretion and confirm our previous findings, we performed transcriptomic analysis in macrophages and identified a subgroup of individuals with CD who had low expression of the autophagy receptor optineurin (OPTN). We then clarified the role of OPTN deficiency in: macrophage cytokine secretion; mouse models of bacteria-driven colitis and peritonitis; and zebrafish Salmonella infection. OPTN-deficient bone-marrow-derived macrophages (BMDMs) stimulated with heat-killed Escherichia coli secreted less proinflammatory TNFα and IL6 cytokines despite similar gene transcription, which normalised with lysosomal and autophagy inhibitors, suggesting that TNFα is mis-trafficked to lysosomes via bafilomycin-A-dependent pathways in the absence of OPTN. OPTN-deficient mice were more susceptible to Citrobacter colitis and E. coli peritonitis, and showed reduced levels of proinflammatory TNFα in serum, diminished neutrophil recruitment to sites of acute inflammation and greater mortality, compared with wild-type mice. Optn-knockdown zebrafish infected with Salmonella also had higher mortality. OPTN plays a role in acute inflammation and neutrophil recruitment, potentially via defective macrophage proinflammatory cytokine secretion, which suggests that diminished OPTN expression in humans might increase the risk of developing CD. PMID:26044960

  11. Neutrophils recruited by chemoattractants in vivo induce microvascular plasma protein leakage through secretion of TNF

    PubMed Central

    Finsterbusch, Michaela; Voisin, Mathieu-Benoit; Beyrau, Martina; Williams, Timothy John

    2014-01-01

    Microvascular plasma protein leakage is an essential component of the inflammatory response and serves an important function in local host defense and tissue repair. Mediators such as histamine and bradykinin act directly on venules to increase the permeability of endothelial cell (EC) junctions. Neutrophil chemoattractants also induce leakage, a response that is dependent on neutrophil adhesion to ECs, but the underlying mechanism has proved elusive. Through application of confocal intravital microscopy to the mouse cremaster muscle, we show that neutrophils responding to chemoattractants release TNF when in close proximity of EC junctions. In vitro, neutrophils adherent to ICAM-1 or ICAM-2 rapidly released TNF in response to LTB4, C5a, and KC. Further, in TNFR−/− mice, neutrophils accumulated normally in response to chemoattractants administered to the cremaster muscle or dorsal skin, but neutrophil-dependent plasma protein leakage was abolished. Similar results were obtained in chimeric mice deficient in leukocyte TNF. A locally injected TNF blocking antibody was also able to inhibit neutrophil-dependent plasma leakage, but had no effect on the response induced by bradykinin. The results suggest that TNF mediates neutrophil-dependent microvascular leakage. This mechanism may contribute to the effects of TNF inhibitors in inflammatory diseases and indicates possible applications in life-threatening acute edema. PMID:24913232

  12. MET is required for the recruitment of anti-tumoural neutrophils

    PubMed Central

    Finisguerra, Veronica; Di Conza, Giusy; Di Matteo, Mario; Serneels, Jens; Costa, Sandra; Thompson, A.A. Roger; Wauters, Els; Walmsley, Sarah; Prenen, Hans; Granot, Zvi; Casazza, Andrea; Mazzone, Massimiliano

    2015-01-01

    Mutations or amplification of the MET proto-oncogene are involved in the pathogenesis of several tumours1-4, which rely on the constitutive engagement of this pathway for their growth and survival1,5. However, MET is expressed not only by cancer cells but also by tumour-associated stromal cells although its precise role in this compartment is not well characterized6-11. Here, we show that MET is required for neutrophil chemoattraction and cytotoxicity in response to its ligand HGF. Met deletion in neutrophils enhances tumour growth and metastasis. This phenotype correlates with reduced neutrophil infiltration to both primary tumour and metastatic site. Similarly, Met is necessary for neutrophil transudation during colitis, skin rash or peritonitis. Mechanistically, Met is induced by tumour-derived TNF-α or other inflammatory stimuli in both mouse and human neutrophils. This induction is instrumental for neutrophil transmigration across an activated endothelium and iNOS production upon HGF stimulation. Consequently, HGF/MET-dependent nitric oxide release by neutrophils promotes cancer cell killing, which abates tumour growth and metastasis. Following systemic administration of a MET kinase inhibitor, we prove that the therapeutic benefit of MET targeting in cancer cells is partly countered by the pro-tumoural effect rising from MET blockade in neutrophils. Our work identifies an unprecedented role of MET in neutrophils, suggests a potential “Achilles’ heel” of MET-targeted therapies in cancer, and supports the rationale for evaluating anti-MET drugs in certain inflammatory diseases. PMID:25985180

  13. GDF-15 inhibits integrin activation and mouse neutrophil recruitment through the ALK-5/TGF-βRII heterodimer.

    PubMed

    Artz, Annette; Butz, Stefan; Vestweber, Dietmar

    2016-07-28

    Growth differentiation factor 15 (GDF-15) is the first cytokine known to counteract chemokine-induced activation of leukocyte integrins. We showed recently that this activity dampens neutrophil recruitment into inflamed tissue and is required for survival of myocardial infarction in mice. The receptor responsible for this GDF-15-triggered anti-inflammatory mechanism on myeloid cells is not known. Here, we identify this receptor as transforming growth factor β receptor I (TGF-βRI) (activin receptor-like kinase 5 [ALK-5]) and TGF-β receptor II (TGF-βRII). We show that interference with these receptors by small-molecule inhibitors, antibodies, or small interfering RNA, blocked the GDF-15 effect on leukocyte integrin activation. Likewise, gene inactivation of each of the 2 receptors in neutrophils isolated from conditional gene-deficient mice abolished the inhibitory effect of GDF-15 on CXCL1-induced β2-integrin activation and neutrophil diapedesis. Rapid neutrophil arrest induced by CXCL1 in vivo was inhibited by GDF-15 in an ALK-5 and TGF-βRII dependent way. As for GDF-15 gene-deficient mice, we found that extravasation of neutrophils deficient for ALK-5 or TGF-βRII was strongly increased in the interleukin-1β inflamed cremaster. The inhibitory effects of GDF-15 on neutrophil integrin activation and in vivo neutrophil arrest were also found for TGF-β1. Mechanistically, GDF-15 and TGF-β1 interfered with integrin activation by inhibiting the activation of Ras-related protein 1 (Rap-1), an effect that depended on CalDAG- guanine nucleotide exchange factor 1 (GEF1) and cell division control protein 42 homolog. We conclude that both GDF-15 and TGF-β1 counteract chemokine-induced integrin activation on neutrophils via the ALK-5/TGF-βRII heterodimer. This represents a novel, rapid anti-inflammatory activity of the 2 TGF-β receptors and of TGF-β1. PMID:27235139

  14. Quantitative Trait Loci and Candidate Genes for Neutrophil Recruitment in Sterile Inflammation Mapped in AXB-BXA Recombinant Inbred Mice

    PubMed Central

    Cheng, Quyen; Seltzer, Ze’ev; Sima, Corneliu; Lakschevitz, Flavia S.; Glogauer, Michael

    2015-01-01

    Neutrophil recruitment (NR) to sites of sterile inflammation plays a key role in tissue damage and healing potential of lesions characteristic to non-infectious inflammatory diseases. Previous studies suggested significant genetic control of neutrophil survival, function, and migration in inflammatory responses to endogenous and exogenous stimuli. We have mapped the murine genome for quantitative trait loci (QTLs) harbouring genetic determinants that regulate NR in SI using a murine model of chemically-induced peritonitis. NR was quantified in 16 AXB-BXA recombinant inbred strains and their progenitors, A/J (A) and C57BL/6J (B). A continuous distribution of NR was found among the strains, with parent B showing higher NR and parent A showing lower NR (3.0-fold difference, p=0.05). Within the progeny strains, a 5.5-fold difference in NR was observed between the lowest, BXA1, and the highest responders AXB19 (p<0.001). This data was analyzed using GeneNetwork, which linked NR to one significant QTL on chromosome 12 (Peritoneal Neutrophil Recruitment 1, PNR1) and two suggestive QTLs (PNR2, PNR3) on chromosomes 12 and 16 respectively. Sixty-four candidate genes within PNR1 were cross-referenced with currently published data, mRNA expression from two NR microarrays, and single nucleotide polymorphism analysis. The present study brings new light into the genetics of NR in response to cell injury and highlights potential candidate genes Hif1α, Fntb, and Prkch and their products for further studies on neutrophil infiltration and inflammation resolution in sterile inflammation. PMID:25942439

  15. Spinal GABA-B receptor modulates neutrophil recruitment to the knee joint in zymosan-induced arthritis.

    PubMed

    Bassi, Gabriel S; do C Malvar, David; Cunha, Thiago M; Cunha, Fernando Q; Kanashiro, Alexandre

    2016-08-01

    Recent studies have demonstrated that the central nervous system controls inflammatory responses by activating complex efferent neuroimmune pathways. The present study was designed to evaluate the role that central gamma-aminobutyric acid type B (GABA-B) receptor plays in neutrophil migration in a murine model of zymosan-induced arthritis by using different pharmacological tools. We observed that intrathecal administration of baclofen, a selective GABA-B agonist, exacerbated the inflammatory response in the knee after zymosan administration characterized by an increase in the neutrophil recruitment and knee joint edema, whereas saclofen, a GABA-B antagonist, exerted the opposite effect. Intrathecal pretreatment of the animals with SB203580 (an inhibitor of p38 mitogen-activated protein kinase) blocked the pro-inflammatory effect of baclofen. On the other hand, systemic administration of guanethidine, a sympatholytic drug that inhibits catecholamine release, and nadolol, a beta-adrenergic receptor antagonist, reversed the effect of saclofen. Moreover, saclofen suppressed the release of the pro-inflammatory cytokines into the knee joint (ELISA) and pain-related behaviors (open field test). Since the anti-inflammatory effect of saclofen depends on the sympathetic nervous system integrity, we observed that isoproterenol, a beta-adrenergic receptor agonist, mimics the central GABA-B blockade decreasing knee joint neutrophil recruitment. Together, these results demonstrate that the pharmacological manipulation of spinal GABAergic transmission aids control of neutrophil migration to the inflamed joint by modulating the activation of the knee joint-innervating sympathetic terminal fibers through a mechanism dependent on peripheral beta-adrenergic receptors and central components, such as p38 MAPK. PMID:27106212

  16. Interleukin-33 facilitates neutrophil recruitment and bacterial clearance in S. aureus-caused peritonitis.

    PubMed

    Lan, Fang; Yuan, Baohong; Liu, Tao; Luo, Xiaochun; Huang, Ping; Liu, Yunjun; Dai, Liangcheng; Yin, Hui

    2016-04-01

    Interleukin (IL)-33, a newly recognized member of IL-1 family of cytokines, plays an important role in polarizing Th2-associated immunity. Recently growing evidence indicates that IL-33 also represents a crucial mediator of antimicrobial infection. In this study, we investigated the effect of IL-33 on antibacterial response using an acute Staphylococcus aureus peritoneal infection model. Our results showed that IL-33 administration induced a rapid bacterial clearance and markedly reduced the S. aureus infection-related mortality. IL-33-treated mice displayed increased neutrophil influx into the focus of infection and higher concentrations of chemokine CXCL2 in the peritoneum than untreated mice. The beneficial effect of IL-33 priming was related to reversal of the S. aureus-induced reduction of CXCR2 expression on the surface of neutrophils. Furthermore, conditioning of neutrophils by IL-33 led to the enhancement of complement receptor 3 expression induced by S. aureus, which in turn facilitates the phagocytosis of opsonized S. aureus. Finally, neutrophils primed by IL-33 upregulated the production of reactive oxygen species and the subsequent killing activity for S. aureus. All together, these findings suggest that IL-33, through regulating multiple steps of neutrophil-mediated bactericidal function, provides a profound effect in host antimicrobial defense response. PMID:26991049

  17. Interleukin 17A promotes pneumococcal clearance by recruiting neutrophils and inducing apoptosis through a p38 mitogen-activated protein kinase-dependent mechanism in acute otitis media.

    PubMed

    Wang, Wei; Zhou, Aie; Zhang, Xuemei; Xiang, Yun; Huang, Yifei; Wang, Lei; Zhang, Shuai; Liu, Yusi; Yin, Yibing; He, Yujuan

    2014-06-01

    Streptococcus pneumoniae is a Gram-positive and human-restricted pathogen colonizing the nasopharynx with an absence of clinical symptoms as well as a major pathogen causing otitis media (OM), one of the most common childhood infections. Upon bacterial infection, neutrophils are rapidly activated and recruited to the infected site, acting as the frontline defender against emerging microbial pathogens via different ways. Evidence shows that interleukin 17A (IL-17A), a neutrophil-inducing factor, plays important roles in the immune responses in several diseases. However, its function in response to S. pneumoniae OM remains unclear. In this study, the function of IL-17A in response to S. pneumoniae OM was examined using an in vivo model. We developed a model of acute OM (AOM) in C57BL/6 mice and found that neutrophils were the dominant immune cells that infiltrated to the middle ear cavity (MEC) and contributed to bacterial clearance. Using IL-17A knockout (KO) mice, we found that IL-17A boosted neutrophil recruitment to the MEC and afterwards induced apoptosis, which was identified to be conducive to bacterial clearance. In addition, our observation suggested that the p38 mitogen-activated protein kinase (MAPK) signaling pathway was involved in the recruitment and apoptosis of neutrophils mediated by IL-17A. These data support the conclusion that IL-17A contributes to the host immune response against S. pneumoniae by promoting neutrophil recruitment and apoptosis through the p38 MAPK signaling pathway. PMID:24664502

  18. Enhanced angiogenesis, hypoxia and neutrophil recruitment during Myc-induced liver tumorigenesis in zebrafish.

    PubMed

    Zhao, Ye; Huang, Xiaoqian; Ding, Tony Weixi; Gong, Zhiyuan

    2016-01-01

    Angiogenesis, hypoxia and immune cells are important components in tumor microenvironment affecting tumor growth. Here we employed a zebrafish liver tumor model to investigate the effect of Myc expression on angiogenesis, hypoxia and tumor-infiltrated neutrophils during the tumor initiation stage. We found that induced Myc expression in the liver caused a dramatic increase of liver size with neoplastic features. The tumorigenic liver was accompanied by enhanced angiogenesis and inhibition of angiogenesis by an inhibitor (SU5416 or sunitinib) hindered the tumorigenic growth, suggesting an essential role of angiogenesis in tumorigenic growth of liver tumor in this zebrafish model. Myc induction also caused hypoxia, which could be further enhanced by hypoxia activator, ML228, to lead to a further enlargement of tumorigenic liver. Furthermore, Myc overexpression incurred an increase of liver-infiltrated neutrophils and the increase could be suppressed by angiogenesis inhibitors or by morpholino knockdown inhibition of neutrophil differentiation, leading to a suppression of growth of tumorigenic livers. Finally, the enhanced angiogenesis, hypoxia and tumor-infiltrated neutrophils by Myc overexpression were validated by RT-qPCR examination of expression of relevant biomarker genes. In sum, the current study demonstrated that the Myc-induced liver tumor model in zebrafish provides an excellent platform for study of tumor microenvironment. PMID:27549025

  19. Enhanced angiogenesis, hypoxia and neutrophil recruitment during Myc-induced liver tumorigenesis in zebrafish

    PubMed Central

    Zhao, Ye; Huang, Xiaoqian; Ding, Tony Weixi; Gong, Zhiyuan

    2016-01-01

    Angiogenesis, hypoxia and immune cells are important components in tumor microenvironment affecting tumor growth. Here we employed a zebrafish liver tumor model to investigate the effect of Myc expression on angiogenesis, hypoxia and tumor-infiltrated neutrophils during the tumor initiation stage. We found that induced Myc expression in the liver caused a dramatic increase of liver size with neoplastic features. The tumorigenic liver was accompanied by enhanced angiogenesis and inhibition of angiogenesis by an inhibitor (SU5416 or sunitinib) hindered the tumorigenic growth, suggesting an essential role of angiogenesis in tumorigenic growth of liver tumor in this zebrafish model. Myc induction also caused hypoxia, which could be further enhanced by hypoxia activator, ML228, to lead to a further enlargement of tumorigenic liver. Furthermore, Myc overexpression incurred an increase of liver-infiltrated neutrophils and the increase could be suppressed by angiogenesis inhibitors or by morpholino knockdown inhibition of neutrophil differentiation, leading to a suppression of growth of tumorigenic livers. Finally, the enhanced angiogenesis, hypoxia and tumor-infiltrated neutrophils by Myc overexpression were validated by RT-qPCR examination of expression of relevant biomarker genes. In sum, the current study demonstrated that the Myc-induced liver tumor model in zebrafish provides an excellent platform for study of tumor microenvironment. PMID:27549025

  20. Trappin-2 promotes early clearance of Pseudomonas aeruginosa through CD14-dependent macrophage activation and neutrophil recruitment.

    PubMed

    Wilkinson, Thomas S; Dhaliwal, Kevin; Hamilton, Thomas W; Lipka, Alexander F; Farrell, Lesley; Davidson, Donald J; Duffin, Rodger; Morris, Andrew Conway; Haslett, Chris; Govan, John R W; Gregory, Christopher D; Sallenave, Jean-Michel; Simpson, A John

    2009-04-01

    Microaspiration of Pseudomonas aeruginosa contributes to the pathogenesis of nosocomial pneumonia. Trappin-2 is a host defense peptide that assists with the clearance of P. aeruginosa through undefined mechanisms. A model of macrophage interactions with replicating P. aeruginosa (strain PA01) in serum-free conditions was developed, and the influence of subantimicrobial concentrations of trappin-2 was subsequently studied. PA01 that was pre-incubated with trappin-2 (at concentrations that have no direct antimicrobial effects), but not control PA01, was cleared by alveolar and bone marrow-derived macrophages. However, trappin-2-enhanced clearance of PA01 was completely abrogated by CD14- null macrophages. Fluorescence microscopy demonstrated the presence of trappin-2 on the bacterial cell surface of trappin-2-treated PA01. In a murine model of early lung infection, trappin-2-treated PA01 was cleared more efficiently than control PA01 2 hours of intratracheal instillation. Furthermore, trappin-2-treated PA01 up-regulated the murine chemokine CXCL1/KC after 2 hours with a corresponding increase in neutrophil recruitment 1 hour later. These in vivo trappin-2-treated PA01 effects were absent in CD14-deficient mice. Trappin-2 appears to opsonize P. aeruginosa for more efficient, CD14-dependent clearance by macrophages and contributes to the induction of chemokines that promote neutrophil recruitment. Trappin-2 may therefore play an important role in innate recognition and clearance of pathogens during the very earliest stages of pulmonary infection. PMID:19264904

  1. Trappin-2 Promotes Early Clearance of Pseudomonas aeruginosa through CD14-Dependent Macrophage Activation and Neutrophil Recruitment

    PubMed Central

    Wilkinson, Thomas S.; Dhaliwal, Kevin; Hamilton, Thomas W.; Lipka, Alexander F.; Farrell, Lesley; Davidson, Donald J.; Duffin, Rodger; Morris, Andrew Conway; Haslett, Chris; Govan, John R.W.; Gregory, Christopher D.; Sallenave, Jean-Michel; Simpson, A. John

    2009-01-01

    Microaspiration of Pseudomonas aeruginosa contributes to the pathogenesis of nosocomial pneumonia. Trappin-2 is a host defense peptide that assists with the clearance of P. aeruginosa through undefined mechanisms. A model of macrophage interactions with replicating P. aeruginosa (strain PA01) in serum-free conditions was developed, and the influence of subantimicrobial concentrations of trappin-2 was subsequently studied. PA01 that was pre-incubated with trappin-2 (at concentrations that have no direct antimicrobial effects), but not control PA01, was cleared by alveolar and bone marrow-derived macrophages. However, trappin-2-enhanced clearance of PA01 was completely abrogated by CD14- null macrophages. Fluorescence microscopy demonstrated the presence of trappin-2 on the bacterial cell surface of trappin-2-treated PA01. In a murine model of early lung infection, trappin-2-treated PA01 was cleared more efficiently than control PA01 2 hours of intratracheal instillation. Furthermore, trappin-2-treated PA01 up-regulated the murine chemokine CXCL1/KC after 2 hours with a corresponding increase in neutrophil recruitment 1 hour later. These in vivo trappin-2-treated PA01 effects were absent in CD14-deficient mice. Trappin-2 appears to opsonize P. aeruginosa for more efficient, CD14-dependent clearance by macrophages and contributes to the induction of chemokines that promote neutrophil recruitment. Trappin-2 may therefore play an important role in innate recognition and clearance of pathogens during the very earliest stages of pulmonary infection. PMID:19264904

  2. Activated prostaglandin D2 receptors on macrophages enhance neutrophil recruitment into the lung

    PubMed Central

    Jandl, Katharina; Stacher, Elvira; Bálint, Zoltán; Sturm, Eva Maria; Maric, Jovana; Peinhaupt, Miriam; Luschnig, Petra; Aringer, Ida; Fauland, Alexander; Konya, Viktoria; Dahlen, Sven-Erik; Wheelock, Craig E.; Kratky, Dagmar; Olschewski, Andrea; Marsche, Gunther; Schuligoi, Rufina; Heinemann, Akos

    2016-01-01

    Background Prostaglandin (PG) D2 is an early-phase mediator in inflammation, but its action and the roles of the 2 D-type prostanoid receptors (DPs) DP1 and DP2 (also called chemoattractant receptor–homologous molecule expressed on TH2 cells) in regulating macrophages have not been elucidated to date. Objective We investigated the role of PGD2 receptors on primary human macrophages, as well as primary murine lung macrophages, and their ability to influence neutrophil action in vitro and in vivo. Methods In vitro studies, including migration, Ca2+ flux, and cytokine secretion, were conducted with primary human monocyte-derived macrophages and neutrophils and freshly isolated murine alveolar and pulmonary interstitial macrophages. In vivo pulmonary inflammation was assessed in male BALB/c mice. Results Activation of DP1, DP2, or both receptors on human macrophages induced strong intracellular Ca2+ flux, cytokine release, and migration of macrophages. In a murine model of LPS-induced pulmonary inflammation, activation of each PGD2 receptor resulted in aggravated airway neutrophilia, tissue myeloperoxidase activity, cytokine contents, and decreased lung compliance. Selective depletion of alveolar macrophages abolished the PGD2-enhanced inflammatory response. Activation of PGD2 receptors on human macrophages enhanced the migratory capacity and prolonged the survival of neutrophils in vitro. In human lung tissue specimens both DP1 and DP2 receptors were located on alveolar macrophages along with hematopoietic PGD synthase, the rate-limiting enzyme of PGD2 synthesis. Conclusion For the first time, our results show that PGD2 markedly augments disease activity through its ability to enhance the proinflammatory actions of macrophages and subsequent neutrophil activation. PMID:26792210

  3. Oncogenic RAS pathway activation promotes resistance to anti-VEGF therapy through G-CSF-induced neutrophil recruitment.

    PubMed

    Phan, Vernon T; Wu, Xiumin; Cheng, Jason H; Sheng, Rebecca X; Chung, Alicia S; Zhuang, Guanglei; Tran, Christopher; Song, Qinghua; Kowanetz, Marcin; Sambrone, Amy; Tan, Martha; Meng, Y Gloria; Jackson, Erica L; Peale, Franklin V; Junttila, Melissa R; Ferrara, Napoleone

    2013-04-01

    Granulocyte-colony stimulating factor (G-CSF) promotes mobilization of CD11b(+)Gr1(+) myeloid cells and has been implicated in resistance to anti-VEGF therapy in mouse models. High G-CSF production has been associated with a poor prognosis in cancer patients. Here we show that activation of the RAS/MEK/ERK pathway regulates G-CSF expression through the Ets transcription factor. Several growth factors induced G-CSF expression by a MEK-dependent mechanism. Inhibition of G-CSF release with a MEK inhibitor markedly reduced G-CSF production in vitro and synergized with anti-VEGF antibodies to reduce CD11b(+)Ly6G(+) neutrophil mobilization and tumor growth and led to increased survival in animal models of cancer, including a genetically engineered mouse model of pancreatic adenocarcinoma. Analysis of biopsies from pancreatic cancer patients revealed increased phospho-MEK, G-CSF, and Ets expression and enhanced neutrophil recruitment compared with normal pancreata. These results provide insights into G-CSF regulation and on the mechanism of action of MEK inhibitors and point to unique anticancer strategies. PMID:23530240

  4. Interleukin-10 plays a key role in the modulation of neutrophils recruitment and lung inflammation during infection by Streptococcus pneumoniae.

    PubMed

    Peñaloza, Hernán F; Nieto, Pamela A; Muñoz-Durango, Natalia; Salazar-Echegarai, Francisco J; Torres, Javiera; Parga, María J; Alvarez-Lobos, Manuel; Riedel, Claudia A; Kalergis, Alexis M; Bueno, Susan M

    2015-09-01

    Streptococcus pneumoniae is a major aetiological agent of pneumonia worldwide, as well as otitis media, sinusitis, meningitis and sepsis. Recent reports have suggested that inflammation of lungs due to S. pneumoniae infection promotes bacterial dissemination and severe disease. However, the contribution of anti-inflammatory molecules to the pathogenesis of S. pneumoniae remains unknown. To elucidate whether the production of the anti-inflammatory cytokine interleukin-10 (IL-10) is beneficial or detrimental for the host during pneumococcal pneumonia, we performed S. pneumoniae infections in mice lacking IL-10 (IL-10(-/-) mice). The IL-10(-/-) mice showed increased mortality, higher expression of pro-inflammatory cytokines, and an exacerbated recruitment of neutrophils into the lungs after S. pneumoniae infection. However, IL-10(-/-) mice showed significantly lower bacterial loads in lungs, spleen, brain and blood, when compared with mice that produced this cytokine. Our results support the notion that production of IL-10 during S. pneumoniae infection modulates the expression of pro-inflammatory cytokines and the infiltration of neutrophils into the lungs. This feature of IL-10 is important to avoid excessive inflammation of tissues and to improve host survival, even though bacterial dissemination is less efficient in the absence of this cytokine. PMID:26032199

  5. Oncogenic RAS pathway activation promotes resistance to anti-VEGF therapy through G-CSF–induced neutrophil recruitment

    PubMed Central

    Phan, Vernon T.; Wu, Xiumin; Cheng, Jason H.; Sheng, Rebecca X.; Chung, Alicia S.; Zhuang, Guanglei; Tran, Christopher; Song, Qinghua; Kowanetz, Marcin; Sambrone, Amy; Tan, Martha; Meng, Y. Gloria; Jackson, Erica L.; Peale, Franklin V.; Junttila, Melissa R.; Ferrara, Napoleone

    2013-01-01

    Granulocyte-colony stimulating factor (G-CSF) promotes mobilization of CD11b+Gr1+ myeloid cells and has been implicated in resistance to anti-VEGF therapy in mouse models. High G-CSF production has been associated with a poor prognosis in cancer patients. Here we show that activation of the RAS/MEK/ERK pathway regulates G-CSF expression through the Ets transcription factor. Several growth factors induced G-CSF expression by a MEK-dependent mechanism. Inhibition of G-CSF release with a MEK inhibitor markedly reduced G-CSF production in vitro and synergized with anti-VEGF antibodies to reduce CD11b+Ly6G+ neutrophil mobilization and tumor growth and led to increased survival in animal models of cancer, including a genetically engineered mouse model of pancreatic adenocarcinoma. Analysis of biopsies from pancreatic cancer patients revealed increased phospho-MEK, G-CSF, and Ets expression and enhanced neutrophil recruitment compared with normal pancreata. These results provide insights into G-CSF regulation and on the mechanism of action of MEK inhibitors and point to unique anticancer strategies. PMID:23530240

  6. Interleukin-10 plays a key role in the modulation of neutrophils recruitment and lung inflammation during infection by Streptococcus pneumoniae

    PubMed Central

    Peñaloza, Hernán F; Nieto, Pamela A; Muñoz-Durango, Natalia; Salazar-Echegarai, Francisco J; Torres, Javiera; Parga, María J; Alvarez-Lobos, Manuel; Riedel, Claudia A; Kalergis, Alexis M; Bueno, Susan M

    2015-01-01

    Streptococcus pneumoniae is a major aetiological agent of pneumonia worldwide, as well as otitis media, sinusitis, meningitis and sepsis. Recent reports have suggested that inflammation of lungs due to S. pneumoniae infection promotes bacterial dissemination and severe disease. However, the contribution of anti-inflammatory molecules to the pathogenesis of S. pneumoniae remains unknown. To elucidate whether the production of the anti-inflammatory cytokine interleukin-10 (IL-10) is beneficial or detrimental for the host during pneumococcal pneumonia, we performed S. pneumoniae infections in mice lacking IL-10 (IL-10−/− mice). The IL-10−/− mice showed increased mortality, higher expression of pro-inflammatory cytokines, and an exacerbated recruitment of neutrophils into the lungs after S. pneumoniae infection. However, IL-10−/− mice showed significantly lower bacterial loads in lungs, spleen, brain and blood, when compared with mice that produced this cytokine. Our results support the notion that production of IL-10 during S. pneumoniae infection modulates the expression of pro-inflammatory cytokines and the infiltration of neutrophils into the lungs. This feature of IL-10 is important to avoid excessive inflammation of tissues and to improve host survival, even though bacterial dissemination is less efficient in the absence of this cytokine. PMID:26032199

  7. IL17 Promotes Mammary Tumor Progression by Changing the Behavior of Tumor Cells and Eliciting Tumorigenic Neutrophils Recruitment.

    PubMed

    Benevides, Luciana; da Fonseca, Denise Morais; Donate, Paula Barbim; Tiezzi, Daniel Guimarães; De Carvalho, Daniel D; de Andrade, Jurandyr M; Martins, Gislaine A; Silva, João S

    2015-09-15

    The aggressiveness of invasive ductal carcinoma (IDC) of the breast is associated with increased IL17 levels. Studying the role of IL17 in invasive breast tumor pathogenesis, we found that metastatic primary tumor-infiltrating T lymphocytes produced elevated levels of IL17, whereas IL17 neutralization inhibited tumor growth and prevented the migration of neutrophils and tumor cells to secondary disease sites. Tumorigenic neutrophils promote disease progression, producing CXCL1, MMP9, VEGF, and TNFα, and their depletion suppressed tumor growth. IL17A also induced IL6 and CCL20 production in metastatic tumor cells, favoring the recruitment and differentiation of Th17. In addition, IL17A changed the gene-expression profile and the behavior of nonmetastatic tumor cells, causing tumor growth in vivo, confirming the protumor role of IL17. Furthermore, high IL17 expression was associated with lower disease-free survival and worse prognosis in IDC patients. Thus, IL17 blockade represents an attractive approach for the control of invasive breast tumors. PMID:26208902

  8. Short-Term Heat Exposure Inhibits Inflammation by Abrogating Recruitment of and Nuclear Factor-κB Activation in Neutrophils Exposed to Chemotactic Cytokines

    PubMed Central

    Choi, Mira; Salanova, Birgit; Rolle, Susanne; Wellner, Maren; Schneider, Wolfgang; Luft, Friedrich C.; Kettritz, Ralph

    2008-01-01

    Cytokines, such as granulocyte macrophage-colony stimulating factor (GM-CSF) and interleukin (IL)-8 attract neutrophils into inflammatory sites. During emigration from the blood neutrophils interact with extracellular matrix proteins such as fibronectin. Fibronectin provides β2-integrin co-stimulation, allowing GM-CSF and IL-8 to activate nuclear factor (NF)-κB, an effect that does not occur in suspension. We tested the hypothesis that exposure of mice to fever-like temperatures abrogates neutrophil recruitment and NF-κB activation in a mouse model of skin inflammation. Mice that were exposed to 40°C for 1 hour showed strongly reduced GM-CSF- and IL-8-induced neutrophilic skin inflammation. In vitro heat exposure did not interfere with neutrophil adhesion or spreading on fibronectin but strongly inhibited migration toward both cytokines. Using specific inhibitors, we found that PI3-K/Akt was pivotal for neutrophil migration and that heat down-regulated this pathway. Furthermore, neutrophils on fibronectin showed abrogated NF-κB activation in response to GM-CSF and IL-8 after heat. In vivo heat exposure of mice followed by ex vivo stimulation of isolated bone marrow neutrophils confirmed these results. Finally, less NF-κB activation was seen in the inflammatory lesions of mice exposed to fever-like temperatures as demonstrated by in situ hybridization for IκBα mRNA. These new findings suggest that heat may have anti-inflammatory effects in neutrophil-dependent inflammation. PMID:18187571

  9. FGF23 signaling impairs neutrophil recruitment and host defense during CKD

    PubMed Central

    Rossaint, Jan; Oehmichen, Jessica; Van Aken, Hugo; Reuter, Stefan; Pavenstädt, Hermann J.; Meersch, Melanie; Unruh, Mark

    2016-01-01

    Chronic kidney disease (CKD) has been associated with impaired host response and increased susceptibility to infections. Leukocyte recruitment during inflammation must be tightly regulated to protect the host against pathogens. FGF23 levels are increased in blood during CKD, and levels of this hormone have been associated with a variety of adverse effects in CKD patients. Here, we have shown that CKD impairs leukocyte recruitment into inflamed tissue and host defense in mice and humans. FGF23 neutralization during CKD in murine models restored leukocyte recruitment and host defense. Intravital microscopy of animals with chronic kidney failure showed that FGF23 inhibits chemokine-activated leukocyte arrest on the endothelium, and downregulation of FGF receptor 2 (FGFR2) on PMNs rescued host defense in these mice. In vitro, FGF23 inhibited PMN adhesion, arrest under flow, and transendothelial migration. Mechanistically, FGF23 binding to FGFR2 counteracted selectin- and chemokine-triggered β2 integrin activation on PMNs by activating protein kinase A (PKA) and inhibiting activation of the small GTPase Rap1. Moreover, knockdown of PKA abolished the inhibitory effect of FGF23 on integrin activation. Together, our data reveal that FGF23 acts directly on PMNs and dampens host defense by direct interference with chemokine signaling and integrin activation. PMID:26878171

  10. Chemokine (C-C Motif) Receptor 1 Is Required for Efficient Recruitment of Neutrophils during Respiratory Infection with Modified Vaccinia Virus Ankara

    PubMed Central

    Price, Philip J. R.; Luckow, Bruno; Torres-Domínguez, Lino E.; Brandmüller, Christine; Zorn, Julia; Kirschning, Carsten J.; Sutter, Gerd

    2014-01-01

    ABSTRACT Modified vaccinia virus Ankara (MVA) serves as a versatile platform in vaccine development. This highly attenuated orthopoxvirus, which cannot replicate in mammalian cells, triggers strong innate immune responses, including cell migration. Previously, we have shown that induction of chemokine (C-C motif) ligand 2 (CCL2) by MVA is necessary for the recruitment of monocytes and T cells, but not neutrophils, to the lung. Here, we identified neutrophil-attracting chemokines produced by MVA-infected primary murine lung fibroblasts and murine bone marrow-derived macrophages. We demonstrate that MVA, but not vaccinia virus (VACV) strain WR, induces chemokine expression, which is independent of Toll-like receptor 2 (TLR2) signaling. Additionally, we show that both chemokine (C-C motif) receptor 1 (CCR1) and chemokine (C-X-C motif) receptor 2 (CXCR2) are involved in MVA-induced neutrophil chemotaxis in vitro. Finally, intranasal infection of Ccr1−/− mice with MVA, as well as application of the CCR1 antagonist J-113863, revealed a role for CCR1 in leukocyte recruitment, including neutrophils, into the lung. IMPORTANCE Rapid attraction of leukocytes to the site of inoculation is unique to MVA in comparison to other VACV strains. The findings here extend current knowledge about the regulation of MVA-induced leukocyte migration, particularly regarding neutrophils, which could potentially be exploited to improve other VACV strains currently in development as oncolytic viruses and viral vectors. Additionally, the data presented here indicate that the inflammatory response may vary depending on the cell type infected by MVA, highlighting the importance of the site of vaccine application. Moreover, the rapid recruitment of neutrophils and other leukocytes can directly contribute to the induction of adaptive immune responses elicited by MVA inoculation. Thus, a better understanding of leukocyte migration upon MVA infection is particularly relevant for further

  11. Extracellular Adenosine Protects against Streptococcus pneumoniae Lung Infection by Regulating Pulmonary Neutrophil Recruitment.

    PubMed

    Bou Ghanem, Elsa N; Clark, Stacie; Roggensack, Sara E; McIver, Sally R; Alcaide, Pilar; Haydon, Philip G; Leong, John M

    2015-08-01

    An important determinant of disease following Streptococcus pneumoniae (pneumococcus) lung infection is pulmonary inflammation mediated by polymorphonuclear leukocytes (PMNs). We found that upon intratracheal challenge of mice, recruitment of PMNs into the lungs within the first 3 hours coincided with decreased pulmonary pneumococci, whereas large numbers of pulmonary PMNs beyond 12 hours correlated with a greater bacterial burden. Indeed, mice that survived infection largely resolved inflammation by 72 hours, and PMN depletion at peak infiltration, i.e. 18 hours post-infection, lowered bacterial numbers and enhanced survival. We investigated host signaling pathways that influence both pneumococcus clearance and pulmonary inflammation. Pharmacologic inhibition and/or genetic ablation of enzymes that generate extracellular adenosine (EAD) (e.g. the ectoenzyme CD73) or degrade EAD (e.g. adenosine deaminase) revealed that EAD dramatically increases murine resistance to S. pneumoniae lung infection. Moreover, adenosine diminished PMN movement across endothelial monolayers in vitro, and although inhibition or deficiency of CD73 had no discernible impact on PMN recruitment within the first 6 hours after intratracheal inoculation of mice, these measures enhanced PMN numbers in the pulmonary interstitium after 18 hours of infection, culminating in dramatically elevated numbers of pulmonary PMNs at three days post-infection. When assessed at this time point, CD73-/- mice displayed increased levels of cellular factors that promote leukocyte migration, such as CXCL2 chemokine in the murine lung, as well as CXCR2 and β-2 integrin on the surface of pulmonary PMNs. The enhanced pneumococcal susceptibility of CD73-/- mice was significantly reversed by PMN depletion following infection, suggesting that EAD-mediated resistance is largely mediated by its effects on PMNs. Finally, CD73-inhibition diminished the ability of PMNs to kill pneumococci in vitro, suggesting that EAD alters

  12. IL-17RA in Non-Hematopoietic Cells Controls CXCL-1 and 5 Critical to Recruit Neutrophils to the Lung of Mycobacteria-Infected Mice during the Adaptive Immune Response

    PubMed Central

    Lombard, Robin; Epardaud, Mathieu; Le Vern, Yves; Buzoni-Gatel, Dominique; Winter, Nathalie

    2016-01-01

    During chronic infection with Mycobacterium tuberculosis (Mtb), bacilli multiplication is constrained within lung granulomas until excessive inflammation destroys the lung. Neutrophils are recruited early and participate in granuloma formation, but excessive neutrophilia exacerbates the tuberculosis disease. Neutrophils thus appear as potential targets for therapeutic interventions, especially in patients for whom no antibiotic treatment is possible. Signals that regulate neutrophil recruitment to the lung during mycobacterial infection need to be better understood. We demonstrated here, in the mouse model, that neutrophils were recruited to the lung in two waves after intranasal infection with virulent Mtb or the live attenuated vaccine strain Bacillus Calmette Guérin (BCG). A first wave of neutrophils was swiftly recruited, followed by a subsequent adaptive wave that reached the lung together with IFN-γ- and IL-17A-producing T cells. Interestingly, the second neutrophil wave did not participate to mycobacteria control in the lung and established contacts with T cells. The adaptive wave was critically dependent on the expression of IL-17RA, the receptor for IL-17A, expressed in non-hematopoietic cells. In absence of this receptor, curtailed CXCL-1 and 5 production in the lung restrained neutrophil recruitment. CXCL-1 and 5 instillation reconstituted lung neutrophil recruitment in BCG-infected IL17RA-/- mice. PMID:26871571

  13. Brucella CβG induces a dual pro- and anti-inflammatory response leading to a transient neutrophil recruitment

    PubMed Central

    Degos, Clara; Gagnaire, Aurélie; Banchereau, Romain; Moriyón, Ignacio; Gorvel, Jean-Pierre

    2015-01-01

    Brucella is the causing agent of a chronic zoonosis called brucellosis. The Brucella β-1,2 cyclic glucan (CβG) is a virulence factor, which has been described as a potent immune stimulator, albeit with no toxicity for cells and animals. We first used a genome-wide approach to characterize human myeloid dendritic cell (mDC) responses to CβG. Transcripts related to inflammation (IL-6, IL2RA, PTGS2), chemokine (CXCR7, CXCL2) and anti-inflammatory pathways (TNFAIP6, SOCS3) were highly expressed in CβG-treated mDC. In mouse GMCSF-derived DC, CβG triggered the expression of both activation (CXCL2, KC) and inhibition (SOCS3 and TNFAIP6) molecules. We then characterized the inflammatory infiltrates at the level of mouse ear when injected with CβG or LPS. CβG yielded a lower and transient recruitment of neutrophils compared to LPS. The consequence of these dual pro- and anti-inflammatory signals triggered by CβG corresponds to the induction of a controlled local inflammation. PMID:25654761

  14. Mast cells mediate neutrophil recruitment and vascular leakage through the NLRP3 inflammasome in histamine-independent urticaria

    PubMed Central

    Nakamura, Yuumi; Saito, Megumu; Nishikomori, Ryuta; Kim, Yun-Gi; Murakami, Makoto; Núñez, Gabriel; Matsue, Hiroyuki

    2009-01-01

    Urticarial rash observed in cryopyrin-associated periodic syndrome (CAPS) caused by nucleotide-binding oligomerization domain–leucine-rich repeats containing pyrin domain 3 (NLRP3) mutations is effectively suppressed by anti–interleukin (IL)-1 treatment, suggesting a pathophysiological role of IL-1β in the skin. However, the cellular mechanisms regulating IL-1β production in the skin of CAPS patients remain unclear. We identified mast cells (MCs) as the main cell population responsible for IL-1β production in the skin of CAPS patients. Unlike normal MCs that required stimulation with proinflammatory stimuli for IL-1β production, resident MCs from CAPS patients constitutively produced IL-1β. Primary MCs expressed inflammasome components and secreted IL-1β via NLRP3 and apoptosis-associated speck-like protein containing a caspase recruitment domain when stimulated with microbial stimuli known to activate caspase-1. Furthermore, MCs expressing disease-associated but not wild-type NLRP3 secreted IL-1β and induced neutrophil migration and vascular leakage, the histological hallmarks of urticarial rash, when transplanted into mouse skin. Our findings implicate MCs as IL-1β producers in the skin and mediators of histamine-independent urticaria through the NLRP3 inflammasome. PMID:19364881

  15. Interleukin-23 (IL-23), independent of IL-17 and IL-22, drives neutrophil recruitment and innate inflammation during Clostridium difficile colitis in mice.

    PubMed

    McDermott, Andrew J; Falkowski, Nicole R; McDonald, Roderick A; Pandit, Chinmay R; Young, Vincent B; Huffnagle, Gary B

    2016-01-01

    Our objective was to determine the role of the inflammatory cytokine interleukin-23 (IL-23) in promoting neutrophil recruitment, inflammatory cytokine expression and intestinal histopathology in response to Clostridium difficile infection. Wild-type (WT) and p19(-/-) (IL-23KO) mice were pre-treated with cefoperazone in their drinking water for 5 days, and after a 2-day recovery period were challenged with spores from C. difficile strain VPI 10463. Interleukin-23 deficiency was associated with significant defects in both the recruitment of CD11b(High) Ly6G(H) (igh) neutrophils to the colon and the expression of neutrophil chemoattractants and stabilization factors including Cxcl1, Cxcl2, Ccl3 and Csf3 within the colonic mucosa as compared with WT animals. Furthermore, the expression of inflammatory cytokines including Il33, Tnf and Il6 was significantly reduced in IL-23-deficient animals. There was also a trend towards less severe colonic histopathology in the absence of IL-23. The induction of Il17a and Il22 was also significantly abrogated in IL-23KO mice. Inflammatory cytokine expression and neutrophilic inflammation were not reduced in IL-17a-deficient mice or in mice treated with anti-IL-22 depleting monoclonal antibody. However, induction of RegIIIg was significantly reduced in animals treated with anti-IL-22 antibody. Taken together, these data indicate that IL-23, but not IL-17a or IL-22, promotes neutrophil recruitment and inflammatory cytokine and chemokine expression in the colon in response to C. difficile infection. PMID:26455347

  16. The α-tocopherol form of vitamin E reverses age-associated susceptibility to streptococcus pneumoniae lung infection by modulating pulmonary neutrophil recruitment.

    PubMed

    Bou Ghanem, Elsa N; Clark, Stacie; Du, Xiaogang; Wu, Dayong; Camilli, Andrew; Leong, John M; Meydani, Simin N

    2015-02-01

    Streptococcus pneumoniae infections are an important cause of morbidity and mortality in older patients. Uncontrolled neutrophil-driven pulmonary inflammation exacerbates this disease. To test whether the α-tocopherol (α-Toc) form of vitamin E, a regulator of immunity, can modulate neutrophil responses as a preventive strategy to mitigate the age-associated decline in resistance to S. pneumoniae, young (4 mo) and old (22-24 mo) C57BL/6 mice were fed a diet containing 30-PPM (control) or 500-PPM (supplemented) α-Toc for 4 wk and intratracheally infected with S. pneumoniae. Aged mice fed a control diet were exquisitely more susceptible to S. pneumoniae than young mice. At 2 d postinfection, aged mice suffered 1000-fold higher pulmonary bacterial burden, 2.2-fold higher levels of neutrophil recruitment to the lung, and a 2.25-fold higher rate of lethal septicemia. Strikingly, α-Toc supplementation of aged mice resulted in a 1000-fold lower bacterial lung burden and full control of infection. This α-Toc-induced resistance to pneumococcal challenge was associated with a 2-fold fewer pulmonary neutrophils, a level comparable to S. pneumoniae-challenged, conventionally fed young mice. α-Toc directly inhibited neutrophil egress across epithelial cell monolayers in vitro in response to pneumococci or hepoxilin-A3, an eicosanoid required for pneumococcus-elicited neutrophil trans-epithelial migration. α-Toc altered expression of multiple epithelial and neutrophil adhesion molecules involved in migration, including CD55, CD47, CD18/CD11b, and ICAM-1. These findings suggest that α-Toc enhances resistance of aged mice to bacterial pneumonia by modulating the innate immune response, a finding that has potential clinical significance in combating infection in aged individuals through nutritional intervention. PMID:25512603

  17. The α-Tocopherol Form of Vitamin E Reverses Age-Associated Susceptibility to Streptococcus pneumoniae Lung Infection by Modulating Pulmonary Neutrophil Recruitment

    PubMed Central

    Ghanem, Elsa N. Bou; Clark, Stacie; Du, Xiaogang; Wu, Dayong; Camilli, Andrew; Leong, John M.; Meydani, Simin N.

    2016-01-01

    Streptococcus pneumoniae infections are an important cause of morbidity and mortality in older patients. Uncontrolled neutrophil-driven pulmonary inflammation exacerbates this disease. To test whether the α-tocopherol (α-Toc) form of vitamin E, a regulator of immunity, can modulate neutrophil responses as a preventive strategy to mitigate the age-associated decline in resistance to S. pneumoniae, young (4 mo) and old (22–24 mo) C57BL/6 mice were fed a diet containing 30-PPM (control) or 500-PPM (supplemented) α-Toc for 4 wk and intratracheally infected with S. pneumoniae. Aged mice fed a control diet were exquisitely more susceptible to S. pneumoniae than young mice. At 2 d postinfection, aged mice suffered 1000-fold higher pulmonary bacterial burden, 2.2-fold higher levels of neutrophil recruitment to the lung, and a 2.25-fold higher rate of lethal septicemia. Strikingly, α-Toc supplementation of aged mice resulted in a 1000-fold lower bacterial lung burden and full control of infection. This α-Toc–induced resistance to pneumococcal challenge was associated with a 2-fold fewer pulmonary neutrophils, a level comparable to S. pneumoniae–challenged, conventionally fed young mice. α-Toc directly inhibited neutrophil egress across epithelial cell monolayers in vitro in response to pneumococci or hepoxilin-A3, an eicosanoid required for pneumococcus-elicited neutrophil trans-epithelial migration. α-Toc altered expression of multiple epithelial and neutrophil adhesion molecules involved in migration, including CD55, CD47, CD18/CD11b, and ICAM-1. These findings suggest that α-Toc enhances resistance of aged mice to bacterial pneumonia by modulating the innate immune response, a finding that has potential clinical significance in combating infection in aged individuals through nutritional intervention. PMID:25512603

  18. Innate immune adaptor MyD88 mediates neutrophil recruitment and myocardial injury after ischemia-reperfusion in mice.

    PubMed

    Feng, Yan; Zhao, Huailong; Xu, Xinhua; Buys, Emmanuel S; Raher, Michael J; Bopassa, Jean C; Thibault, Helene; Scherrer-Crosbie, Marielle; Schmidt, Ulrich; Chao, Wei

    2008-09-01

    MyD88 is an adaptor protein critical for innate immune response against microbial infection and in certain noninfectious tissue injury. The present study examined the role of MyD88 in myocardial inflammation and injury after ischemia-reperfusion (I/R). I/R was produced by coronary artery ligation for 30 min followed by reperfusion. The ratios of area at risk to left ventricle (LV) were similar between wild-type (WT) and MyD88-deficient (MyD88-/-) mice. However, 24 h after I/R, the ratios of myocardial infarction to area at risk were 58% less in MyD88(-/-) than in WT mice (14 +/- 2% vs. 33 +/- 6%, P = 0.01). Serial echocardiographic studies demonstrated that there was no difference in baseline LV contractile function between the two groups. Twenty-four hours after I/R, LV ejection fraction (EF) and fractional shortening (FS) in WT mice were reduced by 44% and 62% (EF, 51 +/- 2%, and FS, 22 +/- 1%, P < 0.001), respectively, and remained depressed on the seventh day after I/R. In comparison, EF and FS in MyD88(-/-) mice were 67 +/- 3% and 33 +/- 2%, respectively, after I/R (P < 0.001 vs. WT). Similarly, LV function, as demonstrated by invasive hemodynamic measurements, was better preserved in MyD88(-/-) compared with WT mice after I/R. Furthermore, when compared with WT mice, MyD88(-/-) mice subjected to I/R had a marked decrease in myocardial inflammation as demonstrated by attenuated neutrophil recruitment and decreased expression of the proinflammatory mediators keratinocyte chemoattractant, monocyte chemoattractant protein-1, and ICAM-1. Taken together, these data suggest that MyD88 modulates myocardial inflammatory injury and contributes to myocardial infarction and LV dysfunction during I/R. PMID:18660455

  19. Neutrophil granulocytes recruited upon translocation of intestinal bacteria enhance graft-versus-host disease via tissue damage.

    PubMed

    Schwab, Lukas; Goroncy, Luise; Palaniyandi, Senthilnathan; Gautam, Sanjivan; Triantafyllopoulou, Antigoni; Mocsai, Attila; Reichardt, Wilfried; Karlsson, Fridrik J; Radhakrishnan, Sabarinath V; Hanke, Kathrin; Schmitt-Graeff, Annette; Freudenberg, Marina; von Loewenich, Friederike D; Wolf, Philipp; Leonhardt, Franziska; Baxan, Nicoleta; Pfeifer, Dietmar; Schmah, Oliver; Schönle, Anne; Martin, Stefan F; Mertelsmann, Roland; Duyster, Justus; Finke, Jürgen; Prinz, Marco; Henneke, Philipp; Häcker, Hans; Hildebrandt, Gerhard C; Häcker, Georg; Zeiser, Robert

    2014-06-01

    Acute graft-versus-host disease (GVHD) considerably limits wider usage of allogeneic hematopoietic cell transplantation (allo-HCT). Antigen-presenting cells and T cells are populations customarily associated with GVHD pathogenesis. Of note, neutrophils are the largest human white blood cell population. The cells cleave chemokines and produce reactive oxygen species, thereby promoting T cell activation. Therefore, during an allogeneic immune response, neutrophils could amplify tissue damage caused by conditioning regimens. We analyzed neutrophil infiltration of the mouse ileum after allo-HCT by in vivo myeloperoxidase imaging and found that infiltration levels were dependent on the local microbial flora and were not detectable under germ-free conditions. Physical or genetic depletion of neutrophils reduced GVHD-related mortality. The contribution of neutrophils to GVHD severity required reactive oxygen species (ROS) because selective Cybb (encoding cytochrome b-245, beta polypeptide, also known as NOX2) deficiency in neutrophils impairing ROS production led to lower levels of tissue damage, GVHD-related mortality and effector phenotype T cells. Enhanced survival of Bcl-xL transgenic neutrophils increased GVHD severity. In contrast, when we transferred neutrophils lacking Toll-like receptor-2 (TLR2), TLR3, TLR4, TLR7 and TLR9, which are normally less strongly activated by translocating bacteria, into wild-type C57BL/6 mice, GVHD severity was reduced. In humans, severity of intestinal GVHD strongly correlated with levels of neutrophils present in GVHD lesions. This study describes a new potential role for neutrophils in the pathogenesis of GVHD in both mice and humans. PMID:24836575

  20. Atrial natriuretic peptide down-regulates neutrophil recruitment on inflamed endothelium by reducing cell deformability and resistance to detachment force

    PubMed Central

    Morikis, Vasilios A.; Radecke, Chris; Jiang, Yanyan; Heinrich, Volkmar; Curry, Fitz-Roy; Simon, Scott I.

    2016-01-01

    BACKGROUND Recombinant atrial natriuretic peptide (ANP) is administered in patients with acute heart failure in Japan to improve renal function and hemodynamics, but its anti-inflammatory effect on activated leukocytes may also contribute to its therapeutic efficacy. OBJECTIVE Examine unconventional role of ANP in neutrophil adhesion to inflamed endothelium. METHODS Human neutrophils were perfused over endothelial monolayers in a microfluidic lab-chip assay. Cell rheology was assessed by micropipette aspiration to assess changes in cortical tension and viscosity. Fluorescence microscopy was applied to measure adhesive contact area and β2-integrin focal bond formation. RESULTS ANP inhibited neutrophil rolling and firm adhesion without influencing the upregulation of cellular adhesion molecules on endothelium or the regulation of high affinity CD18 and shedding of L-selectin during neutrophil activation. Exposed to fluid shear, integrin mediated arrest was disrupted with ANP treatment, which elicited formation of long tethers and diminished cell spreading and contact. This correlated with a ~40% increase in neutrophil viscosity and a reduction in the adhesive footprint. CONCLUSIONS A decrease in cell deformation and neutrophil flattening with ANP results in fewer integrin bond clusters, which translates to higher tensile forces and impaired adhesion strengthening and cell detachment. PMID:26639357

  1. Innate immune adaptor MyD88 mediates neutrophil recruitment and myocardial injury after ischemia-reperfusion in mice

    PubMed Central

    Feng , Yan; Zhao, Huailong; Xu, Xinhua; Buys, Emmanuel S.; Raher, Michael J.; Bopassa, Jean C.; Thibault, Helene; Scherrer-Crosbie, Marielle; Schmidt, Ulrich; Chao, Wei

    2008-01-01

    MyD88 is an adaptor protein critical for innate immune response against microbial infection and in certain noninfectious tissue injury. The present study examined the role of MyD88 in myocardial inflammation and injury after ischemia-reperfusion (I/R). I/R was produced by coronary artery ligation for 30 min followed by reperfusion. The ratios of area at risk to left ventricle (LV) were similar between wild-type (WT) and MyD88-deficient (MyD88−/−) mice. However, 24 h after I/R, the ratios of myocardial infarction to area at risk were 58% less in MyD88−/− than in WT mice (14 ± 2% vs. 33 ± 6%, P = 0.01). Serial echocardiographic studies demonstrated that there was no difference in baseline LV contractile function between the two groups. Twenty-four hours after I/R, LV ejection fraction (EF) and fractional shortening (FS) in WT mice were reduced by 44% and 62% (EF, 51 ± 2%, and FS, 22 ± 1%, P < 0.001), respectively, and remained depressed on the seventh day after I/R. In comparison, EF and FS in MyD88−/− mice were 67 ± 3% and 33 ± 2%, respectively, after I/R (P < 0.001 vs. WT). Similarly, LV function, as demonstrated by invasive hemodynamic measurements, was better preserved in MyD88−/− compared with WT mice after I/R. Furthermore, when compared with WT mice, MyD88−/− mice subjected to I/R had a marked decrease in myocardial inflammation as demonstrated by attenuated neutrophil recruitment and decreased expression of the proinflammatory mediators keratinocyte chemoattractant, monocyte chemoattractant protein-1, and ICAM-1. Taken together, these data suggest that MyD88 modulates myocardial inflammatory injury and contributes to myocardial infarction and LV dysfunction during I/R. PMID:18660455

  2. Vinpocetine reduces lipopolysaccharide-induced inflammatory pain and neutrophil recruitment in mice by targeting oxidative stress, cytokines and NF-κB.

    PubMed

    Ruiz-Miyazawa, Kenji W; Pinho-Ribeiro, Felipe A; Zarpelon, Ana C; Staurengo-Ferrari, Larissa; Silva, Rangel L; Alves-Filho, Jose C; Cunha, Thiago M; Cunha, Fernando Q; Casagrande, Rubia; Verri, Waldiceu A

    2015-07-25

    In response to lipopolysaccharide (LPS), tissue resident macrophages and recruited neutrophils produce inflammatory mediators through activation of Toll-like receptor 4 (TLR4)/nuclear factor kappa B (NF-κB) signaling pathway. These mediators include inflammatory cytokines and reactive oxygen species that, in turn, sensitize nociceptors and lead to inflammatory pain. Vinpocetine is a nootropic drug widely used to treat cognitive and neurovascular disorders, and more recently its anti-inflammatory properties through inhibition of NF-κB activation have been described. In the present study, we used the intraplantar and intraperitoneal LPS stimulus in mice to investigate the effects of vinpocetine pre-treatment (3, 10, or 30mg/kg by gavage) in hyperalgesia, leukocyte recruitment, oxidative stress, and pro-inflammatory cytokine production (TNF-α, IL-1β, and IL-33). LPS-induced NF-κB activation and cytokine production were investigated using RAW 264.7 macrophage cell in vitro. Vinpocetine (30mg/kg) significantly reduces hyperalgesia to mechanical and thermal stimuli, and myeloperoxidase (MPO) activity (a neutrophil marker) in the plantar paw skin, and also inhibits neutrophil and mononuclear cell recruitment, superoxide anion and nitric oxide production, oxidative stress, and cytokine production (TNF-α, IL-1β and IL-33) in the peritoneal cavity. At least in part, these effects seem to be mediated by direct effects of vinpocetine on macrophages, since it inhibited the production of the same cytokines (TNF-α, IL-1β and IL-33) and the NF-κB activation in LPS-stimulated RAW 264.7 macrophages. Our results suggest that vinpocetine represents an important therapeutic approach to treat inflammation and pain induced by a gram-negative bacterial component by targeting NF-κB activation and NF-κB-related cytokine production in macrophages. PMID:25980587

  3. Preferential Recruitment of Neutrophils into the Cerebellum and Brainstem Contributes to the Atypical Experimental Autoimmune Encephalomyelitis Phenotype.

    PubMed

    Liu, Yudong; Holdbrooks, Andrew T; Meares, Gordon P; Buckley, Jessica A; Benveniste, Etty N; Qin, Hongwei

    2015-08-01

    The JAK/STAT pathway is critical for development, regulation, and termination of immune responses, and dysregulation of the JAK/STAT pathway, that is, hyperactivation, has pathological implications in autoimmune and neuroinflammatory diseases. Suppressor of cytokine signaling 3 (SOCS3) regulates STAT3 activation in response to cytokines that play important roles in the pathogenesis of neuroinflammatory diseases, including IL-6 and IL-23. We previously demonstrated that myeloid lineage-specific deletion of SOCS3 resulted in a severe, nonresolving atypical form of experimental autoimmune encephalomyelitis (EAE), characterized by lesions, inflammatory infiltrates, elevated STAT activation, and elevated cytokine and chemokine expression in the cerebellum. Clinically, these mice exhibit ataxia and tremors. In this study, we provide a detailed analysis of this model, demonstrating that the atypical EAE observed in LysMCre-SOCS3(fl/fl) mice is characterized by extensive neutrophil infiltration into the cerebellum and brainstem, increased inducible NO synthase levels in the cerebellum and brainstem, and prominent axonal damage. Importantly, infiltrating SOCS3-deficient neutrophils produce high levels of CXCL2, CCL2, CXCL10, NO, TNF-α, and IL-1β. Kinetic studies demonstrate that neutrophil infiltration into the cerebellum and brainstem of LysMCre-SOCS3(fl/fl) mice closely correlates with atypical EAE clinical symptoms. Ab-mediated depletion of neutrophils converts the atypical phenotype to the classical EAE phenotype and, in some cases, a mixed atypical/classical phenotype. Blocking CXCR2 signaling ameliorates atypical EAE development by reducing neutrophil infiltration into the cerebellum/brainstem. Thus, neutrophils lacking SOCS3 display elevated STAT3 activation and expression of proinflammatory mediators and play a critical role in the development of atypical EAE. PMID:26085687

  4. Tumour inflammasome-derived IL-1β recruits neutrophils and improves local recurrence-free survival in EBV-induced nasopharyngeal carcinoma

    PubMed Central

    Chen, Lih-Chyang; Wang, Li-Jie; Tsang, Nang-Ming; Ojcius, David M; Chen, Chia-Chun; OuYang, Chun-Nan; Hsueh, Chuen; Liang, Ying; Chang, Kai-Ping; Chen, Chiu-Chin; Chang, Yu-Sun

    2012-01-01

    Inflammasomes sense infection and cellular damage and are critical for triggering inflammation through IL-1β production. In carcinogenesis, inflammasomes may have contradictory roles through facilitating antitumour immunity and inducing oncogenic factors. Their function in cancer remains poorly characterized. Here we show that the NLRP3, AIM2 and RIG-I inflammasomes are overexpressed in Epstein-Barr virus (EBV)-associated nasopharyngeal carcinoma (NPC), and expression levels correlate with patient survival. In tumour cells, AIM2 and RIG-I are required for IL-1β induction by EBV genomic DNA and EBV-encoded small RNAs, respectively, while NLRP3 responds to extracellular ATP and reactive oxygen species. Irradiation and chemotherapy can further activate AIM2 and NLRP3, respectively. In mice, tumour-derived IL-1β inhibits tumour growth and enhances survival through host responses. Mechanistically, IL-1β-mediated anti-tumour effects depend on infiltrated immunostimulatory neutrophils. We show further that presence of tumour-associated neutrophils is significantly associated with better survival in NPC patients. Thus, tumour inflammasomes play a key role in tumour control by recruiting neutrophils, and their expression levels are favourable prognostic markers and promising therapeutic targets in patients. PMID:23065753

  5. Effects of leukotriene B4 in the human lung. Recruitment of neutrophils into the alveolar spaces without a change in protein permeability.

    PubMed Central

    Martin, T R; Pistorese, B P; Chi, E Y; Goodman, R B; Matthay, M A

    1989-01-01

    Leukotriene B4 (LTB4) is a major product of human alveolar macrophages and has potent chemotactic activity for neutrophils (PMN) in vitro. To evaluate the effects of LTB4 in the normal human lung, we instilled LTB4 (5 X 10(-7)M, 10 ml) into a subsegment of the right middle lobe and 0.9% NaCl (10 ml) into a subsegment of the lingula using a fiberoptic bronchoscope in 12 healthy human volunteers. 4 h later, we performed bronchoalveolar lavage of the same subsegments. Compared with the NaCl instillation, LTB4 caused a large increase in lavage total cells (NaCl = 6.8 +/- 1.0 X 10(6) vs. LTB4 = 26.4 +/- 5.0 X 10(6), P less than 0.01), most of which were PMN (NaCl = 12.2 +/- 4.6% vs. LTB4 = 55.7 +/- 6.0%, P less than 0.001). In contrast, there was only a small increase in lavage total protein, and the lavage total protein correlated weakly with lavage total cells and PMN. The production of superoxide anion by the lavage PMN in response to phorbol myristate acetate was similar to that of peripheral blood PMN. The migration of lavage PMN was normal toward the chemotactic peptide FMLP, but reduced toward LTB4 and zymosan-activated human serum. Morphometric analysis using transmission electron microscopy indicated a selective loss of small granules in the lung neutrophils as compared with peripheral blood neutrophils. The data indicate that in the normal human lung, LTB4 can recruit active PMN into the airspaces without causing a significant change in the protein permeability of the epithelial barrier. Images PMID:2553777

  6. Polymorphonuclear Neutrophils Are Necessary for the Recruitment of CD8+ T Cells in the Liver in a Pregnant Mouse Model of Chlamydophila abortus (Chlamydia psittaci Serotype 1) Infection

    PubMed Central

    de Oca, Roberto Montes; Buendía, Antonio J.; Del Río, Laura; Sánchez, Joaquín; Salinas, Jesús; Navarro, Jose A.

    2000-01-01

    The role of polymorphonuclear neutrophils (PMNs) in the development of the specific immune response against Chlamydophila abortus (Chlamydia psittaci serotype 1) infection was studied in a pregnant mouse model involving treatment with RB6-8C5 monoclonal antibody. PMN depletion significantly affected the immune response in the liver, in which the T-lymphocyte and F4/80+ cell populations decreased, particularly the CD8+ T-cell population. A Th1-like response, characterized by high levels of gamma interferon without detectable levels of interleukin 4 (IL-4) in serum, was observed in both depleted and nondepleted mice, although an increased production of IL-10 was detected in the depleted group. Our results suggest that PMNs play a very important role in the recruitment of other leukocyte populations to the inflammatory foci but have little influence in the polarization of the immune specific response toward a Th1-like response. PMID:10679002

  7. Lipopolysaccharide modulates neutrophil recruitment and macrophage polarization on lymphatic vessels and impairs lymphatic function in rat mesentery.

    PubMed

    Chakraborty, Sanjukta; Zawieja, Scott D; Wang, Wei; Lee, Yang; Wang, Yuan J; von der Weid, Pierre-Yves; Zawieja, David C; Muthuchamy, Mariappan

    2015-12-15

    Impairment of the lymphatic system is apparent in multiple inflammatory pathologies connected to elevated endotoxins such as LPS. However, the direct mechanisms by which LPS influences the lymphatic contractility are not well understood. We hypothesized that a dynamic modulation of innate immune cell populations in mesentery under inflammatory conditions perturbs tissue cytokine/chemokine homeostasis and subsequently influences lymphatic function. We used rats that were intraperitoneally injected with LPS (10 mg/kg) to determine the changes in the profiles of innate immune cells in the mesentery and in the stretch-mediated contractile responses of isolated lymphatic preparations. Results demonstrated a reduction in the phasic contractile activity of mesenteric lymphatic vessels from LPS-injected rats and a severe impairment of lymphatic pump function and flow. There was a significant reduction in the number of neutrophils and an increase in monocytes/macrophages present on the lymphatic vessels and in the clear mesentery of the LPS group. This population of monocytes and macrophages established a robust M2 phenotype, with the majority showing high expression of CD163 and CD206. Several cytokines and chemoattractants for neutrophils and macrophages were significantly changed in the mesentery of LPS-injected rats. Treatment of lymphatic muscle cells (LMCs) with LPS showed significant changes in the expression of adhesion molecules, VCAM1, ICAM1, CXCR2, and galectin-9. LPS-TLR4-mediated regulation of pAKT, pERK pI-κB, and pMLC20 in LMCs promoted both contractile and inflammatory pathways. Thus, our data provide the first evidence connecting the dynamic changes in innate immune cells on or near the lymphatics and complex cytokine milieu during inflammation with lymphatic dysfunction. PMID:26453331

  8. Ecto-5′-Nucleotidase (CD73) Deficiency in Mycobacterium tuberculosis-Infected Mice Enhances Neutrophil Recruitment

    PubMed Central

    Petit-Jentreau, Laetitia; Jouvion, Grégory; Charles, Patricia; Majlessi, Laleh; Gicquel, Brigitte

    2015-01-01

    The immune system needs safeguards that prevent collateral tissue damage mediated by the immune system while enabling an effective response against a pathogen. The purinergic pathway is one such mechanism and finely modulates inflammation by sensing nucleotides in the environment. Extracellular ATP is considered to be a danger signal leading to a proinflammatory response, whereas adenosine is immunosuppressive. CD73, also called ecto-5′-nucleotidase, occupies a strategic position in this pathway, as it is the main enzyme responsible for the generation of adenosine from ATP. Here, we explore the role of CD73 during tuberculosis, a disease characterized by an immune response that is harmful to the host and unable to eradicate Mycobacterium tuberculosis. Using CD73 knockout (KO) mice, we found that CD73 regulates the response to M. tuberculosis infection in vitro and in vivo. Mycobacterium-infected murine macrophages derived from CD73 KO mice secrete more keratinocyte chemoattractant (KC), tumor necrosis factor alpha (TNF-α), and interleukin-6 (IL-6) and release less vascular endothelial growth factor (VEGF) upon ATP stimulation than do those derived from wild-type (WT) mice. In vivo, CD73 limits the early influx of neutrophils to the lungs without affecting bacterial growth and dissemination. Collectively, our results support the view that CD73 fine-tunes antimycobacterial immune responses. PMID:26150535

  9. Epithelial Cell Apoptosis and Neutrophil Recruitment in Acute Lung Injury—A Unifying Hypothesis? What We Have Learned from Small Interfering RNAs

    PubMed Central

    Perl, Mario; Lomas-Neira, Joanne; Chung, Chun-Shiang; Ayala, Alfred

    2008-01-01

    In spite of protective ventilatory strategies, Acute Lung Injury (ALI) remains associated with high morbidity and mortality. One reason for the lack of therapeutic options might be that ALI is a co-morbid event associated with a diverse family of diseases and, thus, may be the result of distinct pathological processes. Among them, activated neutrophil- (PMN-) induced tissue injury and epithelial cell apoptosis mediated lung damage represent two potentially important candidate pathomechanisms that have been put forward. Several approaches have been undertaken to test these hypotheses, with substantial success in the treatment of experimental forms of ALI. With this in mind, we will summarize these two current hypotheses of ALI briefly, emphasizing the role of apoptosis in regulating PMN and/or lung epithelial cell responses. In addition, the contribution that Fas-mediated inflammation may play as a potential biological link between lung cell apoptosis and PMN recruitment will be considered, as well as the in vivo application of small interfering RNA (siRNA) as a novel approach to the inhibition of ALI and its therapeutic implications. PMID:18368145

  10. The Multifaceted Functions of Neutrophils

    PubMed Central

    Mayadas, Tanya N.; Cullere, Xavier; Lowell, Clifford A.

    2014-01-01

    Neutrophils and neutrophil-like cells are the major pathogen-fighting immune cells in organisms ranging from slime molds to mammals. Central to their function is their ability to be recruited to sites of infection, to recognize and phagocytose microbes, and then to kill pathogens through a combination of cytotoxic mechanisms. These include the production of reactive oxygen species, the release of antimicrobial peptides, and the recently discovered expulsion of their nuclear contents to form neutrophil extracellular traps. Here we discuss these primordial neutrophil functions, which also play key roles in tissue injury, by providing details of neutrophil cytotoxic functions and congenital disorders of neutrophils. In addition, we present more recent evidence that interactions between neutrophils and adaptive immune cells establish a feed-forward mechanism that amplifies pathologic inflammation. These newly appreciated contributions of neutrophils are described in the setting of several inflammatory and autoimmune diseases. PMID:24050624

  11. The lymph node neutrophil.

    PubMed

    Hampton, Henry R; Chtanova, Tatyana

    2016-04-01

    Secondary lymphoid organs provide a specialized microenvironment tailored to foster communication between cells of the innate and adaptive immune systems. These interactions allow immune cells to coordinate multilayered defense against pathogens. Until recently dendritic cells and macrophages were thought to comprise the main innate immune cell subsets responsible for delivering signals that drive the adaptive immune response, while the function of neutrophils was largely confined to the innate immune system. However, the discovery of neutrophils in lymph nodes has raised the question of whether neutrophils might play a more extensive role not only in innate immunity per se, but also in coordinating the interactions between innate and adaptive immune responses. In this review we discuss the mechanisms and consequences of neutrophil recruitment to lymph nodes and how this recruitment influences subsequent immune responses both in situ and at distant sites. PMID:27025975

  12. Neutrophil swarming: an essential process of the neutrophil tissue response.

    PubMed

    Kienle, Korbinian; Lämmermann, Tim

    2016-09-01

    Neutrophil infiltration into inflamed and infected tissues is a fundamental process of the innate immune response. While neutrophil interactions with the blood vessel wall have been intensely studied over the last decades, neutrophil dynamics beyond the vasculature have for a long time remained poorly investigated. Recent intravital microscopy studies of neutrophil populations directly at the site of tissue damage or microbial invasion have changed our perspective on neutrophil responses within tissues. Swarm-like migration patterns of neutrophils, referred to as 'neutrophil swarming', have been detected in diverse tissues under conditions of sterile inflammation and infection with various pathogens, including bacteria, fungi, and parasites. Current work has begun to unravel the molecular pathways choreographing the sequential phases of highly coordinated chemotaxis followed by neutrophil accumulation and the formation of substantial neutrophil clusters. It is now clear that intercellular communication among neutrophils amplifies their recruitment in a feed-forward manner, which provides them with a level of self-organization during neutrophil swarming. This review will summarize recent developments and current concepts on neutrophil swarming, an important process of the neutrophil tissue response with a critical role in maintaining the balance between host protection and inflammation-driven tissue destruction. PMID:27558329

  13. Low intensity laser therapy (LILT) in vivo acts on the neutrophils recruitment and chemokines/cytokines levels in a model of acute pulmonary inflammation induced by aerosol of lipopolysaccharide from Escherichia coli in rat.

    PubMed

    Mafra de Lima, F; Villaverde, A B; Salgado, M A; Castro-Faria-Neto, H C; Munin, E; Albertini, R; Aimbire, F

    2010-12-01

    It has been suggested that low intensity laser therapy (LILT) acts on pulmonary inflammation. Thus, we investigate in this work if LILT (650nm, 2.5mW, 31.2mW/cm(2), 1.3J/cm(2), laser spot size of 0.08cm(2) and irradiation time of 42s) can attenuate edema, neutrophil recruitment and inflammatory mediators in acute lung inflammation. Thirty-five male Wistar rats (n=7 per group) were distributed in the following experimental groups: control, laser, LPS, LPS+laser and dexamethasone+LPS. Airway inflammation was measured 4h post-LPS challenge. Pulmonary microvascular leakage was used for measuring pulmonary edema. Bronchoalveolar lavage fluid (BALF) cellularity and myeloperoxidase (MPO) were used for measuring neutrophil recruitment and activation. RT-PCR was performed in lung tissue to assess mRNA expression of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), interleukin (IL-10), cytokine-induced neutrophil chemoattractant-1 (CINC-1), macrophage inflammatory protein-2 (MIP-2) and intercellular adhesion molecule-1 (ICAM-1). Protein levels in both BALF and lung were determined by ELISA. LILT inhibited pulmonary edema and endothelial cytoskeleton damage, as well as neutrophil influx and activation. Similarly, the LILT reduced the TNF-α and IL-1β, in lung and BALF. LILT prevented lung ICAM-1 up-regulation. The rise of CINC-1 and MIP-2 protein levels in both lung and BALF, and the lung mRNA expressions for IL-10, were unaffected. Data suggest that the LILT effect is due to the inhibition of ICAM-1 via the inhibition of TNF-α and IL-1β. PMID:20728373

  14. Interleukin-17 contributes to generation of Th1 immunity and neutrophil recruitment during Chlamydia muridarum genital tract infection but is not required for macrophage influx or normal resolution of infection.

    PubMed

    Scurlock, Amy M; Frazer, Lauren C; Andrews, Charles W; O'Connell, Catherine M; Foote, Isaac P; Bailey, Sarabeth L; Chandra-Kuntal, Kumar; Kolls, Jay K; Darville, Toni

    2011-03-01

    Interleukin 17 (IL-17) contributes to development of Th1 immunity and neutrophil influx during Chlamydia muridarum pulmonary infection, but its role during C. muridarum genital tract infection has not been described. We detected similar numbers of Chlamydia-specific Th17 and Th1 cells in iliac nodes of wild-type mice early during genital C. muridarum infection, while Th1 cells predominated later. il17ra(-/-) mice exhibited a reduced chlamydia-specific Th1 response in draining iliac nodes and decreased local IFN-γ production. Neutrophil influx into the genital tract was also decreased. However, il17ra(-/-) mice resolved infection normally, and no difference in pathology was observed compared to the wild type. Macrophage influx and tumor necrosis factor alpha (TNF-α) production were increased in il17ra(-/-) mice, providing a compensatory mechanism to effectively control chlamydial genital tract infection despite a reduced Th1 response. In ifnγ(-/-) mice, a marked increase in cellular infiltrates and chronic pathology was associated with an increased Th17 response. Although neutralization of IL-17 in ifnγ(-/-) mice decreased neutrophil influx, macrophage infiltration remained intact and the bacterial burden was not increased. Collectively, these results indicate that IL-17 contributes to the generation of Th1 immunity and neutrophil recruitment but is not required for macrophage influx or normal resolution of C. muridarum genital infection. These data highlight the redundant immune mechanisms operative at this mucosal site and the importance of examining site-specific responses to mucosal pathogens. PMID:21149587

  15. Interleukin-17 Contributes to Generation of Th1 Immunity and Neutrophil Recruitment during Chlamydia muridarum Genital Tract Infection but Is Not Required for Macrophage Influx or Normal Resolution of Infection ▿

    PubMed Central

    Scurlock, Amy M.; Frazer, Lauren C.; Andrews, Charles W.; O'Connell, Catherine M.; Foote, Isaac P.; Bailey, Sarabeth L.; Chandra-Kuntal, Kumar; Kolls, Jay K.; Darville, Toni

    2011-01-01

    Interleukin 17 (IL-17) contributes to development of Th1 immunity and neutrophil influx during Chlamydia muridarum pulmonary infection, but its role during C. muridarum genital tract infection has not been described. We detected similar numbers of Chlamydia-specific Th17 and Th1 cells in iliac nodes of wild-type mice early during genital C. muridarum infection, while Th1 cells predominated later. il17ra−/− mice exhibited a reduced chlamydia-specific Th1 response in draining iliac nodes and decreased local IFN-γ production. Neutrophil influx into the genital tract was also decreased. However, il17ra−/− mice resolved infection normally, and no difference in pathology was observed compared to the wild type. Macrophage influx and tumor necrosis factor alpha (TNF-α) production were increased in il17ra−/− mice, providing a compensatory mechanism to effectively control chlamydial genital tract infection despite a reduced Th1 response. In ifnγ−/− mice, a marked increase in cellular infiltrates and chronic pathology was associated with an increased Th17 response. Although neutralization of IL-17 in ifnγ−/− mice decreased neutrophil influx, macrophage infiltration remained intact and the bacterial burden was not increased. Collectively, these results indicate that IL-17 contributes to the generation of Th1 immunity and neutrophil recruitment but is not required for macrophage influx or normal resolution of C. muridarum genital infection. These data highlight the redundant immune mechanisms operative at this mucosal site and the importance of examining site-specific responses to mucosal pathogens. PMID:21149587

  16. Lower Respiratory Tract Infection of the Ferret by 2009 H1N1 Pandemic Influenza A Virus Triggers Biphasic, Systemic, and Local Recruitment of Neutrophils

    PubMed Central

    Camp, Jeremy V.; Bagci, Ulas; Chu, Yong-Kyu; Squier, Brendan; Fraig, Mostafa; Uriarte, Silvia M.; Guo, Haixun; Mollura, Daniel J.

    2015-01-01

    ABSTRACT Infection of the lower respiratory tract by influenza A viruses results in increases in inflammation and immune cell infiltration in the lung. The dynamic relationships among the lung microenvironments, the lung, and systemic host responses during infection remain poorly understood. Here we used extensive systematic histological analysis coupled with live imaging to gain access to these relationships in ferrets infected with the 2009 H1N1 pandemic influenza A virus (H1N1pdm virus). Neutrophil levels rose in the lungs of H1N1pdm virus-infected ferrets 6 h postinfection and became concentrated at areas of the H1N1pdm virus-infected bronchiolar epithelium by 1 day postinfection (dpi). In addition, neutrophil levels were increased throughout the alveolar spaces during the first 3 dpi and returned to baseline by 6 dpi. Histochemical staining revealed that neutrophil infiltration in the lungs occurred in two waves, at 1 and 3 dpi, and gene expression within microenvironments suggested two types of neutrophils. Specifically, CCL3 levels, but not CXCL8/interleukin 8 (IL-8) levels, were higher within discrete lung microenvironments and coincided with increased infiltration of neutrophils into the lung. We used live imaging of ferrets to monitor host responses within the lung over time with [18F]fluorodeoxyglucose (FDG). Sites in the H1N1pdm virus-infected ferret lung with high FDG uptake had high levels of proliferative epithelium. In summary, neutrophils invaded the H1N1pdm virus-infected ferret lung globally and focally at sites of infection. Increased neutrophil levels in microenvironments did not correlate with increased FDG uptake; hence, FDG uptake may reflect prior infection and inflammation of lungs that have experienced damage, as evidenced by bronchial regeneration of tissues in the lungs at sites with high FDG levels. IMPORTANCE Severe influenza disease is characterized by an acute infection of the lower airways that may progress rapidly to organ failure

  17. STK11/LKB1 Deficiency Promotes Neutrophil Recruitment and Proinflammatory Cytokine Production to Suppress T-cell Activity in the Lung Tumor Microenvironment.

    PubMed

    Koyama, Shohei; Akbay, Esra A; Li, Yvonne Y; Aref, Amir R; Skoulidis, Ferdinandos; Herter-Sprie, Grit S; Buczkowski, Kevin A; Liu, Yan; Awad, Mark M; Denning, Warren L; Diao, Lixia; Wang, Jing; Parra-Cuentas, Edwin R; Wistuba, Ignacio I; Soucheray, Margaret; Thai, Tran; Asahina, Hajime; Kitajima, Shunsuke; Altabef, Abigail; Cavanaugh, Jillian D; Rhee, Kevin; Gao, Peng; Zhang, Haikuo; Fecci, Peter E; Shimamura, Takeshi; Hellmann, Matthew D; Heymach, John V; Hodi, F Stephen; Freeman, Gordon J; Barbie, David A; Dranoff, Glenn; Hammerman, Peter S; Wong, Kwok-Kin

    2016-03-01

    STK11/LKB1 is among the most commonly inactivated tumor suppressors in non-small cell lung cancer (NSCLC), especially in tumors harboring KRAS mutations. Many oncogenes promote immune escape, undermining the effectiveness of immunotherapies, but it is unclear whether the inactivation of tumor suppressor genes, such as STK11/LKB1, exerts similar effects. In this study, we investigated the consequences of STK11/LKB1 loss on the immune microenvironment in a mouse model of KRAS-driven NSCLC. Genetic ablation of STK11/LKB1 resulted in accumulation of neutrophils with T-cell-suppressive effects, along with a corresponding increase in the expression of T-cell exhaustion markers and tumor-promoting cytokines. The number of tumor-infiltrating lymphocytes was also reduced in LKB1-deficient mouse and human tumors. Furthermore, STK11/LKB1-inactivating mutations were associated with reduced expression of PD-1 ligand PD-L1 in mouse and patient tumors as well as in tumor-derived cell lines. Consistent with these results, PD-1-targeting antibodies were ineffective against Lkb1-deficient tumors. In contrast, treating Lkb1-deficient mice with an IL6-neutralizing antibody or a neutrophil-depleting antibody yielded therapeutic benefits associated with reduced neutrophil accumulation and proinflammatory cytokine expression. Our findings illustrate how tumor suppressor mutations can modulate the immune milieu of the tumor microenvironment, and they offer specific implications for addressing STK11/LKB1-mutated tumors with PD-1-targeting antibody therapies. PMID:26833127

  18. Neutrophils in Cancer: Two Sides of the Same Coin

    PubMed Central

    Uribe-Querol, Eileen; Rosales, Carlos

    2015-01-01

    Neutrophils are the most abundant leukocytes in blood and are considered to be the first line of defense during inflammation and infections. In addition, neutrophils are also found infiltrating many types of tumors. Tumor-associated neutrophils (TANs) have relevant roles in malignant disease. Indeed neutrophils may be potent antitumor effector cells. However, increasing clinical evidence shows TANs correlate with poor prognosis. The tumor microenvironment controls neutrophil recruitment and in turn TANs help tumor progression. Hence, TANs can be beneficial or detrimental to the host. It is the purpose of this review to highlight these two sides of the neutrophil coin in cancer and to describe recent studies that provide some light on the mechanisms for neutrophil recruitment to the tumor, for neutrophils supporting tumor progression, and for neutrophil activation to enhance their antitumor functions. PMID:26819959

  19. Tumor necrosis factor-α-induced colitis increases NADPH oxidase 1 expression, oxidative stress, and neutrophil recruitment in the colon: preventive effect of apocynin.

    PubMed

    Mouzaoui, Souad; Djerdjouri, Bahia; Makhezer, Nesrine; Kroviarski, Yolande; El-Benna, Jamel; Dang, Pham My-Chan

    2014-01-01

    Reactive oxygen species- (ROS-) mediated injury has been implicated in several inflammatory disorders, including inflammatory bowel disease (IBD). NADPH oxidases (NOXs) are the major source of endogenous ROS. Here, we investigated the role of NOXs derived-ROS in a mouse model of colitis induced by the proinflammatory cytokine, tumor necrosis factor-α (TNF-α). Intraperitoneal injection of TNFα (10 μg · kg(-1)) induced an acute inflammation of the colon and a marked increase in expression of NADPH oxidase 1 (NOX1), a colon specific NADPH oxidase isoform. TNFα-induced colitis was also characterized by high production of keratinocyte-derived chemokine (KC) and mucosal infiltration of neutrophils, NOX2-expressing cells. Concomitantly, ROS production and lipid peroxidation were significantly enhanced while catalase activity and glutathione level were reduced indicating a redox imbalance in the colon. Furthermore, the redox-sensitive MAP kinases, ERK1/2 and p38 MAPK, were activated during TNFα-induced colitis. Pretreatment of mice with apocynin, an NADPH oxidase inhibitor with antioxidant properties, before TNFα challenge, prevented all these events. These data suggest that ROS derived from NADPH oxidases (mainly NOX1 and NOX2) and MAP kinase pathways could contribute to the induction and expansion of oxidative lesions characteristics of IBD and that apocynin could potentially be beneficial in IBD treatment. PMID:25276054

  20. Anti-inflammatory Effect of Methyl Gallate on Experimental Arthritis: Inhibition of Neutrophil Recruitment, Production of Inflammatory Mediators, and Activation of Macrophages.

    PubMed

    Correa, Luana Barbosa; Pádua, Tatiana Almeida; Seito, Leonardo Noboru; Costa, Thadeu Estevam Moreira Maramaldo; Silva, Magaiver Andrade; Candéa, André Luis Peixoto; Rosas, Elaine Cruz; Henriques, Maria G

    2016-06-24

    Methyl gallate (MG) is a prevalent phenolic acid in the plant kingdom, and its presence in herbal medicines might be related to its remarkable biological effects, such as its antioxidant, antitumor, and antimicrobial activities. Although some indirect evidence suggests anti-inflammatory activity for MG, there are no studies demonstrating this effect in animal models. Herein, we demonstrated that MG (0.7-70 mg/kg) inhibited zymosan-induced experimental arthritis in a dose-dependent manner. The oral administration of MG (7 mg/kg) attenuates arthritis induced by zymosan, affecting edema formation, leukocyte migration, and the production of inflammatory mediators (IL-1β, IL-6, TNF-α, CXCL-1, LTB4, and PGE2). Pretreatment with MG inhibited in vitro neutrophil chemotaxis elicited by CXCL-1, as well as the adhesion of these cells to TNF-α-primed endothelial cells. MG also impaired zymosan-stimulated macrophages by inhibiting IL-6 and NO production, COX-2 and iNOS expression, and intracellular calcium mobilization. Thus, MG is likely to present an anti-inflammatory effect by targeting multiple cellular events such as the production of various inflammatory mediators, as well as leukocyte activation and migration. PMID:27227459

  1. Tumor Necrosis Factor-α-Induced Colitis Increases NADPH Oxidase 1 Expression, Oxidative Stress, and Neutrophil Recruitment in the Colon: Preventive Effect of Apocynin

    PubMed Central

    Mouzaoui, Souad; Djerdjouri, Bahia; Makhezer, Nesrine; Kroviarski, Yolande; El-Benna, Jamel; Dang, Pham My-Chan

    2014-01-01

    Reactive oxygen species- (ROS-) mediated injury has been implicated in several inflammatory disorders, including inflammatory bowel disease (IBD). NADPH oxidases (NOXs) are the major source of endogenous ROS. Here, we investigated the role of NOXs derived-ROS in a mouse model of colitis induced by the proinflammatory cytokine, tumor necrosis factor-α (TNF-α). Intraperitoneal injection of TNFα (10 μg · kg−1) induced an acute inflammation of the colon and a marked increase in expression of NADPH oxidase 1 (NOX1), a colon specific NADPH oxidase isoform. TNFα-induced colitis was also characterized by high production of keratinocyte-derived chemokine (KC) and mucosal infiltration of neutrophils, NOX2-expressing cells. Concomitantly, ROS production and lipid peroxidation were significantly enhanced while catalase activity and glutathione level were reduced indicating a redox imbalance in the colon. Furthermore, the redox-sensitive MAP kinases, ERK1/2 and p38 MAPK, were activated during TNFα-induced colitis. Pretreatment of mice with apocynin, an NADPH oxidase inhibitor with antioxidant properties, before TNFα challenge, prevented all these events. These data suggest that ROS derived from NADPH oxidases (mainly NOX1 and NOX2) and MAP kinase pathways could contribute to the induction and expansion of oxidative lesions characteristics of IBD and that apocynin could potentially be beneficial in IBD treatment. PMID:25276054

  2. Regulation of immune responses by neutrophils.

    PubMed

    Wang, Jing; Arase, Hisashi

    2014-06-01

    Neutrophils, the most abundant circulating cells in humans, are major pathogen-killing immune cells. For many years, these cells were considered to be simple killers at the "bottom" of immune responses. However, recent studies have revealed more sophisticated mechanisms associated with neutrophilic cytotoxic functions, and neutrophils have been shown to contribute to various infectious and inflammatory diseases. In this review, we discuss the key features of neutrophils during inflammatory responses, from their release from the bone marrow to their death in inflammatory loci. We also discuss the expanding roles of neutrophils that have been identified in the context of several inflammatory diseases. We further focus on the mechanisms that regulate neutrophil recruitment to inflamed tissues and neutrophil cytotoxic activities against both pathogens and host tissues. PMID:24850053

  3. A comparison of the pulmonary defenses against streptococcal infection in rats and mice following O3 exposure: Differences in disease susceptibility and neutrophil recruitment

    SciTech Connect

    Gilmour, M.I.; Selgrade, M.K. )

    1993-12-01

    Ozone (O3) exposure reduces alveolar macrophage (AM) phagocytosis in mice and increases their susceptibility to Streptococcus zooepidemicus. O3 exposure also decreases AM phagocytosis in rats but does not result in mortality to infection. To investigate the mechanism of disease protection in rats, antibacterial defenses of two strains of mice and F344 rats were compared. O3 exposure (3 hr, 0.4 or 0.8 ppm) and infection with S. zooepidemicus resulted in a dose-dependent proliferation of bacteria in the lungs of mice and high mortality. Polymorphonuclear leukocytes (PMNs) were observed in severely affected individuals 2 or more days postinfection and did not alter the fatal infection. In contrast, microbial inactivation was only impaired in O3-exposed rat lungs during the first 48 hr after infection. In these animals PMNs could be isolated from bronchoalveolar lavage fluid between 6 and 48 hr postinfection with the peak response occurring at 24 hr. Pretreatment with anti-PMN serum eliminated the neutrophil influx and impaired further the bactericidal activity in ozone-exposed rats. The results suggest that inhaled streptococci are cleared normally from the mouse lung by AMs. Following exposure to O3, AM phagocytosis is reduced and the mice develop a fatal infection. The persistence of bacteria in the lungs of O3-exposed rats triggers a transient influx of PMNs whose appearance corresponds with elimination of the bacteria. Differences in antimicrobial defenses between various experimental species and humans need to be better understood in order to predict effects of air pollutants on susceptibility to infection in man.

  4. Pulmonary neutrophil recruitment and bronchial reactivity in formaldehyde-exposed rats are modulated by mast cells and differentially by neuropeptides and nitric oxide

    SciTech Connect

    Lino dos Santos Franco, Adriana; Damazo, Amilcar Sabino; Beraldo de Souza, Hyula Regines; Domingos, Helory Vanni; Oliveira-Filho, Ricardo Martins; Oliani, Sonia Maria; Costa, Soraia Katia Pereira; Tavares de Lima, Wothan . E-mail: wtdelima@icb.usp.br

    2006-07-01

    We have used a pharmacological approach to study the mechanisms underlying the rat lung injury and the airway reactivity changes induced by inhalation of formaldehyde (FA) (1% formalin solution, 90 min once a day, 4 days). The reactivity of isolated tracheae and intrapulmonary bronchi were assessed in dose-response curves to methacholine (MCh). Local and systemic inflammatory phenomena were evaluated in terms of leukocyte countings in bronchoalveolar lavage (BAL) fluid, blood, bone marrow lavage and spleen. Whereas the tracheal reactivity to MCh did not change, a significant bronchial hyporesponsiveness (BHR) was found after FA inhalation as compared with naive rats. Also, FA exposure significantly increased the total cell numbers in BAL, in peripheral blood and in the spleen, but did not modify the counts in bone marrow. Capsaicin hindered the increase of leukocyte number recovered in BAL fluid after FA exposure. Both compound 48/80 and indomethacin were able to prevent the lung neutrophil influx after FA, but indomethacin had no effect on that of mononuclear cells. Following FA inhalation, the treatment with sodium cromoglycate (SCG), but not with the nitric oxide (NO) synthase inhibitor L-NAME, significantly reduced the total cell number in BAL. Compound 48/80, L-NAME and SCG significantly prevented BHR to MCh after FA inhalation, whereas capsaicin was inactive in this regard. On the other hand, indomethacin exacerbated BHR. These data suggest that after FA inhalation, the resulting lung leukocyte influx and BHR may involve nitric oxide, airway sensory fibers and mast cell-derived mediators. The effect of NO seemed to be largely restricted to the bronchial tonus, whereas neuropeptides appeared to be linked to the inflammatory response, therefore indicating that the mechanisms responsible for the changes of airway responsiveness caused by FA may be separate from those underlying its inflammatory lung effects.

  5. Feedback Amplification of Neutrophil Function.

    PubMed

    Németh, Tamás; Mócsai, Attila

    2016-06-01

    As the first line of innate immune defense, neutrophils need to mount a rapid and robust antimicrobial response. Recent studies implicate various positive feedback amplification processes in achieving that goal. Feedback amplification ensures effective migration of neutrophils in shallow chemotactic gradients, multiple waves of neutrophil recruitment to the site of inflammation, and the augmentation of various effector functions of the cells. We review here such positive feedback loops including intracellular and autocrine processes, paracrine effects mediated by lipid (LTB4), chemokine, and cytokine mediators, and bidirectional interactions with the complement system and with other immune and non-immune cells. These amplification mechanisms are not only involved in antimicrobial immunity but also contribute to neutrophil-mediated tissue damage under pathological conditions. PMID:27157638

  6. Neutrophil Functions in Periodontal Homeostasis.

    PubMed

    Cortés-Vieyra, Ricarda; Rosales, Carlos; Uribe-Querol, Eileen

    2016-01-01

    Oral tissues are constantly exposed to damage from the mechanical effort of eating and to microorganisms, mostly bacteria. In healthy gingiva tissue remodeling and a balance between bacteria and innate immune cells are maintained. However, excess of bacteria biofilm (plaque) creates an inflammation state that recruits more immune cells, mainly neutrophils to the gingiva. Neutrophils create a barrier for bacteria to reach inside tissues. When neutrophils are insufficient, bacteria thrive causing more inflammation that has been associated with systemic effects on other conditions such as atherosclerosis, diabetes, and cancer. But paradoxically when neutrophils persist, they can also promote a chronic inflammatory state that leads to periodontitis, a condition that leads to damage of the bone-supporting tissues. In periodontitis, bone loss is a serious complication. How a neutrophil balance is needed for maintaining healthy oral tissues is the focus of this review. We present recent evidence on how alterations in neutrophil number and function can lead to inflammatory bone loss, and how some oral bacteria signal neutrophils to block their antimicrobial functions and promote an inflammatory state. Also, based on this new information, novel therapeutic approaches are discussed. PMID:27019855

  7. Neutrophil Functions in Periodontal Homeostasis

    PubMed Central

    Cortés-Vieyra, Ricarda; Rosales, Carlos

    2016-01-01

    Oral tissues are constantly exposed to damage from the mechanical effort of eating and to microorganisms, mostly bacteria. In healthy gingiva tissue remodeling and a balance between bacteria and innate immune cells are maintained. However, excess of bacteria biofilm (plaque) creates an inflammation state that recruits more immune cells, mainly neutrophils to the gingiva. Neutrophils create a barrier for bacteria to reach inside tissues. When neutrophils are insufficient, bacteria thrive causing more inflammation that has been associated with systemic effects on other conditions such as atherosclerosis, diabetes, and cancer. But paradoxically when neutrophils persist, they can also promote a chronic inflammatory state that leads to periodontitis, a condition that leads to damage of the bone-supporting tissues. In periodontitis, bone loss is a serious complication. How a neutrophil balance is needed for maintaining healthy oral tissues is the focus of this review. We present recent evidence on how alterations in neutrophil number and function can lead to inflammatory bone loss, and how some oral bacteria signal neutrophils to block their antimicrobial functions and promote an inflammatory state. Also, based on this new information, novel therapeutic approaches are discussed. PMID:27019855

  8. Moesin regulates neutrophil rolling velocity in vivo.

    PubMed

    Matsumoto, Masanori; Hirata, Takako

    2016-01-01

    During inflammation, the selectin-induced slow rolling of neutrophils on venules cooperates with chemokine signaling to mediate neutrophil recruitment into tissues. Previous studies identified P-selectin glycoprotein ligand-1 (PSGL-1) and CD44 as E-selectin ligands that activate integrins to induce slow rolling. We show here that in TNF-α-treated cremaster muscle venules, slow leukocyte rolling was impaired in mice deficient in moesin, a member of the ezrin-radixin-moesin (ERM) family. Accordingly, neutrophil recruitment in a peritonitis model was decreased in moesin-deficient mice when chemokine signaling was blocked with pertussis toxin. These results suggest that moesin contributes to the slow rolling and subsequent recruitment of neutrophils during inflammation. PMID:27131737

  9. Neutrophil Responses to Sterile Implant Materials

    PubMed Central

    Jhunjhunwala, Siddharth; Aresta-DaSilva, Stephanie; Tang, Katherine; Alvarez, David; Webber, Matthew J.; Tang, Benjamin C.; Lavin, Danya M.; Veiseh, Omid; Doloff, Joshua C.; Bose, Suman; Vegas, Arturo; Ma, Minglin; Sahay, Gaurav; Chiu, Alan; Bader, Andrew; Langan, Erin; Siebert, Sean; Li, Jie; Greiner, Dale L.; Newburger, Peter E.; von Andrian, Ulrich H.; Langer, Robert; Anderson, Daniel G.

    2015-01-01

    In vivo implantation of sterile materials and devices results in a foreign body immune response leading to fibrosis of implanted material. Neutrophils, one of the first immune cells to be recruited to implantation sites, have been suggested to contribute to the establishment of the inflammatory microenvironment that initiates the fibrotic response. However, the precise numbers and roles of neutrophils in response to implanted devices remains unclear. Using a mouse model of peritoneal microcapsule implantation, we show 30–500 fold increased neutrophil presence in the peritoneal exudates in response to implants. We demonstrate that these neutrophils secrete increased amounts of a variety of inflammatory cytokines and chemokines. Further, we observe that they participate in the foreign body response through the formation of neutrophil extracellular traps (NETs) on implant surfaces. Our results provide new insight into neutrophil function during a foreign body response to peritoneal implants which has implications for the development of biologically compatible medical devices. PMID:26355958

  10. Different Leishmania Species Drive Distinct Neutrophil Functions.

    PubMed

    Hurrell, Benjamin P; Regli, Ivo B; Tacchini-Cottier, Fabienne

    2016-05-01

    Leishmaniases are vector-borne diseases of serious public health importance. During a sand fly blood meal, Leishmania parasites are deposited in the host dermis where neutrophils are rapidly recruited. Neutrophils are the first line of defense and can kill pathogens by an array of mechanisms. They can also form web-like structures called neutrophil extracellular traps (NETs) that can trap and/or kill microbes. The function of neutrophils in leishmaniasis was reported to be either beneficial by contributing to parasite killing or detrimental by impairing immune response development and control of parasite load. Here we review recent data showing that different Leishmania species elicit distinct neutrophil functions thereby influencing disease outcomes. Emerging evidence suggests that neutrophils should be considered important modulators of leishmaniasis. PMID:26944469

  11. Alarmins Link Neutrophils and Dendritic Cells

    PubMed Central

    Yang, De; de la Rosa, Gonzalo; Tewary, Poonam; Oppenheim, Joost J.

    2009-01-01

    Neutrophils are the first major population of leukocyte to infiltrate infected or injured tissues and are crucial for initiating host innate defense and adaptive immunity. Although the contribution of neutrophils to innate immune defense is mediated predominantly by phagocytosis and killing of microorganisms, neutrophils also participate in the induction of adaptive immune responses. At sites of infection and/or injury, neutrophils release numerous mediators upon degranulation or death, among these are alarmins which have a characteristic dual capacity to mobilize and activate antigen-presenting cells. We describe here how alarmins released by neutrophil degranulation and/or death can link neutrophils to dendritic cells by promoting their recruitment and activation, resulting in the augmentation of innate and adaptive immune responses. PMID:19699678

  12. Promoting effect of neutrophils on lung tumorigenesis is mediated by CXCR2 and neutrophil elastase

    PubMed Central

    2013-01-01

    Background Tumor cells produce various cytokines and chemokines that attract leukocytes. Leukocytes can amplify parenchymal innate immune responses, and have been shown to contribute to tumor promotion. Neutrophils are among the first cells to arrive at sites of inflammation, and the increased number of tumor-associated neutrophils is linked to poorer outcome in patients with lung cancer. Results We have previously shown that COPD-like airway inflammation promotes lung cancer in a K-ras mutant mouse model of lung cancer (CC-LR). This was associated with severe lung neutrophilic influx due to the increased level of neutrophil chemoattractant, KC. To further study the role of neutrophils in lung tumorigenesis, we depleted neutrophils in CC-LR mice using an anti-neutrophil antibody. This resulted in a significant reduction in lung tumor number. We further selectively inhibited the main receptor for neutrophil chemo-attractant KC, CXCR2. Similarly, this resulted in suppression of neutrophil recruitment into the lung of CC-LR mice followed by significant tumor reduction. Neutrophil elastase (NE) is a potent elastolytic enzyme produced by neutrophils at the site of inflammation. We crossed the CC-LR mice with NE knock-out mice, and found that lack of NE significantly inhibits lung cancer development. These were associated with significant reduction in tumor cell proliferation and angiogenesis. Conclusion We conclude that lung cancer promotion by inflammation is partly mediated by activation of the IL-8/CXCR2 pathway and subsequent recruitment of neutrophils and release of neutrophil elastase. This provides a baseline for future clinical trials using the IL-8/CXCR2 pathway or NE inhibitors in patients with lung cancer. PMID:24321240

  13. Intergrin-dependent neutrophil migration in the injured mouse cornea

    Technology Transfer Automated Retrieval System (TEKTRAN)

    As an early responder to an inflammatory stimulus, neutrophils must exit the vasculature and migrate through the extravascular tissue to the site of insult, which is often remote from the point of extravasation. Following a central epithelial corneal abrasion, neutrophils recruited from the peripher...

  14. Neutrophils: Between Host Defence, Immune Modulation, and Tissue Injury

    PubMed Central

    Kruger, Philipp; Saffarzadeh, Mona; Weber, Alexander N. R.; Rieber, Nikolaus; Radsak, Markus; von Bernuth, Horst; Benarafa, Charaf; Roos, Dirk; Skokowa, Julia; Hartl, Dominik

    2015-01-01

    Neutrophils, the most abundant human immune cells, are rapidly recruited to sites of infection, where they fulfill their life-saving antimicrobial functions. While traditionally regarded as short-lived phagocytes, recent findings on long-term survival, neutrophil extracellular trap (NET) formation, heterogeneity and plasticity, suppressive functions, and tissue injury have expanded our understanding of their diverse role in infection and inflammation. This review summarises our current understanding of neutrophils in host-pathogen interactions and disease involvement, illustrating the versatility and plasticity of the neutrophil, moving between host defence, immune modulation, and tissue damage. PMID:25764063

  15. The influence of early neutrophil-Leishmania interactions on the host immune response to infection

    PubMed Central

    Ribeiro-Gomes, Flavia L.; Sacks, David

    2012-01-01

    Neutrophils are the first cells recruited to the dermal site of Leishmania infection following injection by needle or sand fly bite. The role of neutrophils in either promoting or suppressing host immunity remains controversial. We discuss the events driving neutrophil recruitment, their interaction with the parasite and apoptotic fate, and the nature of their encounters with other innate cells. We suggest that the influence of the neutrophil response on infection outcome critically depends on the timing of their recruitment and the tissue environment in which it occurs. PMID:22919650

  16. Excessive Neutrophils and Neutrophil Extracellular Traps Contribute to Acute Lung Injury of Influenza Pneumonitis

    PubMed Central

    Narasaraju, Teluguakula; Yang, Edwin; Samy, Ramar Perumal; Ng, Huey Hian; Poh, Wee Peng; Liew, Audrey-Ann; Phoon, Meng Chee; van Rooijen, Nico; Chow, Vincent T.

    2011-01-01

    Complications of acute respiratory distress syndrome (ARDS) are common among critically ill patients infected with highly pathogenic influenza viruses. Macrophages and neutrophils constitute the majority of cells recruited into infected lungs, and are associated with immunopathology in influenza pneumonia. We examined pathological manifestations in models of macrophage- or neutrophil-depleted mice challenged with sublethal doses of influenza A virus H1N1 strain PR8. Infected mice depleted of macrophages displayed excessive neutrophilic infiltration, alveolar damage, and increased viral load, later progressing into ARDS-like pathological signs with diffuse alveolar damage, pulmonary edema, hemorrhage, and hypoxemia. In contrast, neutrophil-depleted animals showed mild pathology in lungs. The brochoalveolar lavage fluid of infected macrophage-depleted mice exhibited elevated protein content, T1-α, thrombomodulin, matrix metalloproteinase-9, and myeloperoxidase activities indicating augmented alveolar-capillary damage, compared to neutrophil-depleted animals. We provide evidence for the formation of neutrophil extracellular traps (NETs), entangled with alveoli in areas of tissue injury, suggesting their potential link with lung damage. When co-incubated with infected alveolar epithelial cells in vitro, neutrophils from infected lungs strongly induced NETs generation, and augmented endothelial damage. NETs induction was abrogated by anti-myeloperoxidase antibody and an inhibitor of superoxide dismutase, thus implying that NETs generation is induced by redox enzymes in influenza pneumonia. These findings support the pathogenic effects of excessive neutrophils in acute lung injury of influenza pneumonia by instigating alveolar-capillary damage. PMID:21703402

  17. Exosomes Mediate LTB4 Release during Neutrophil Chemotaxis.

    PubMed

    Majumdar, Ritankar; Tavakoli Tameh, Aidin; Parent, Carole A

    2016-01-01

    Leukotriene B4 (LTB4) is secreted by chemotactic neutrophils, forming a secondary gradient that amplifies the reach of primary chemoattractants. This strategy increases the recruitment range for neutrophils and is important during inflammation. Here, we show that LTB4 and its synthesizing enzymes localize to intracellular multivesicular bodies that, upon stimulation, release their content as exosomes. Purified exosomes can activate resting neutrophils and elicit chemotactic activity in a LTB4 receptor-dependent manner. Inhibition of exosome release leads to loss of directional motility with concomitant loss of LTB4 release. Our findings establish that the exosomal pool of LTB4 acts in an autocrine fashion to sensitize neutrophils towards the primary chemoattractant, and in a paracrine fashion to mediate the recruitment of neighboring neutrophils in trans. We envision that this mechanism is used by other signals to foster communication between cells in harsh extracellular environments. PMID:26741884

  18. Neutrophils--a key component of ischemia-reperfusion injury.

    PubMed

    Schofield, Zoe Victoria; Woodruff, Trent Martin; Halai, Reena; Wu, Mike Chia-Lun; Cooper, Matthew Allister

    2013-12-01

    Ischemia-reperfusion injury (IRI) is a common occurrence following myocardial infarction, transplantation, stroke, and trauma that can lead to multiple organ failure, which remains the foremost cause of death in critically ill patients. Current therapeutic strategies for IRI are mainly palliative, and there is an urgent requirement for a therapeutic that could prevent or reverse tissue damage caused by IRI. Neutrophils are the primary responders following ischemia and reperfusion and represent important components in the protracted inflammatory response and severity associated with IRI. Experimental studies demonstrate neutrophil infiltration at the site of ischemia and show that inducing neutropenia can protect organs from IRI. In this review, we highlight the mechanisms involved in neutrophil recruitment, activation, and adherence and how this contributes to disease severity in IRI. Inhibiting neutrophil mobilization, tissue recruitment, and ultimately neutrophil-associated activation of local and systemic inflammatory responses may have therapeutic potential in the amelioration of local and remote tissue damage following IRI. PMID:24088997

  19. Exosomes Mediate LTB4 Release during Neutrophil Chemotaxis

    PubMed Central

    Majumdar, Ritankar; Tavakoli Tameh, Aidin; Parent, Carole A.

    2016-01-01

    Leukotriene B4 (LTB4) is secreted by chemotactic neutrophils, forming a secondary gradient that amplifies the reach of primary chemoattractants. This strategy increases the recruitment range for neutrophils and is important during inflammation. Here, we show that LTB4 and its synthesizing enzymes localize to intracellular multivesicular bodies that, upon stimulation, release their content as exosomes. Purified exosomes can activate resting neutrophils and elicit chemotactic activity in a LTB4 receptor-dependent manner. Inhibition of exosome release leads to loss of directional motility with concomitant loss of LTB4 release. Our findings establish that the exosomal pool of LTB4 acts in an autocrine fashion to sensitize neutrophils towards the primary chemoattractant, and in a paracrine fashion to mediate the recruitment of neighboring neutrophils in trans. We envision that this mechanism is used by other signals to foster communication between cells in harsh extracellular environments. PMID:26741884

  20. Chemokine Regulation of Neutrophil Infiltration of Skin Wounds

    PubMed Central

    Su, Yingjun; Richmond, Ann

    2015-01-01

    Significance: Efficient recruitment of neutrophils to an injured skin lesion is an important innate immune response for wound repair. Defects in neutrophil recruitment lead to impaired wound healing. Recent Advances: Chemokines and chemokine receptors are known to regulate neutrophil recruitment. Recent research advances reveal more mechanistic details about the regulation of chemokines and chemokine receptors on neutrophil egress from bone marrow, transmigration into the wound site, spatial navigation toward the necrotic skin tissue, and apoptosis-induced clearance by efferocytosis. Critical Issues: Skin injury triggers local and systemic alterations in the expression of multiple chemotactic molecules and the magnitude of chemokine receptor-mediated signaling. The responses of a number of CXC and CX3C chemokines and their receptors closely associate with the temporal and spatial recruitment of neutrophils to wound sites during the inflammatory phase and promote the clearance of necrotic neutrophils during the transition into the proliferative phase. Functional aberrancy in these chemokines and chemokine receptor systems is recognized as one of the important mechanisms underlying the pathology of impaired wound healing. Future Directions: Future research should aim to investigate the therapeutic modulation of neutrophil activity through the targeting of specific chemokines or chemokine receptors in the early inflammatory phase to improve clinical management of wound healing. PMID:26543677

  1. Human filarial Wolbachia lipopeptide directly activates human neutrophils in vitro.

    PubMed

    Tamarozzi, F; Wright, H L; Johnston, K L; Edwards, S W; Turner, J D; Taylor, M J

    2014-10-01

    The host inflammatory response to the Onchocerca volvulus endosymbiont, Wolbachia, is a major contributing factor in the development of chronic pathology in humans (onchocerciasis/river blindness). Recently, the toll-like pattern recognition receptor motif of the major inflammatory ligands of filarial Wolbachia, membrane-associated diacylated lipoproteins, was functionally defined in murine models of pathology, including mediation of neutrophil recruitment to the cornea. However, the extent to which human neutrophils can be activated in response to this Wolbachia pattern recognition motif is not known. Therefore, the responses of purified peripheral blood human neutrophils to a synthetic N-terminal diacylated lipopeptide (WoLP) of filarial Wolbachia peptidoglycan-associated lipoprotein (PAL) were characterized. WoLP exposure led to a dose-dependent activation of healthy, human neutrophils that included gross morphological alterations and modulation of surface expressed integrins involved in tethering, rolling and extravasation. WoLP exposure induced chemotaxis but not chemokinesis of neutrophils, and secretion of the major neutrophil chemokine, interleukin 8. WoLP also induced and primed the respiratory burst, and enhanced neutrophil survival by delay of apoptosis. These results indicate that the major inflammatory motif of filarial Wolbachia lipoproteins directly activates human neutrophils in vitro and promotes a molecular pathway by which human neutrophils are recruited to sites of Onchocerca parasitism. PMID:24909063

  2. How neutrophils kill fungi.

    PubMed

    Gazendam, Roel P; van de Geer, Annemarie; Roos, Dirk; van den Berg, Timo K; Kuijpers, Taco W

    2016-09-01

    Neutrophils play a critical role in the prevention of invasive fungal infections. Whereas mouse studies have demonstrated the role of various neutrophil pathogen recognition receptors (PRRs), signal transduction pathways, and cytotoxicity in the murine antifungal immune response, much less is known about the killing of fungi by human neutrophils. Recently, novel primary immunodeficiencies have been identified in patients with a susceptibility to fungal infections. These human 'knock-out' neutrophils expand our knowledge to understand the role of PRRs and signaling in human fungal killing. From the studies with these patients it is becoming clear that neutrophils employ fundamentally distinct mechanisms to kill Candida albicans or Aspergillus fumigatus. PMID:27558342

  3. Neutrophil's weapons in atherosclerosis.

    PubMed

    Chistiakov, Dimitry A; Bobryshev, Yuri V; Orekhov, Alexander N

    2015-12-01

    Neutrophils are important components of immunity associated with inflammatory responses against a broad spectrum of pathogens. These cells could be rapidly activated by proinflammatory stimuli and migrate to the inflamed and infected sites where they release a variety of cytotoxic molecules with antimicrobial activity. Neutrophil antibacterial factors include extracellular proteases, redox enzymes, antimicrobial peptides, and small bioactive molecules. In resting neutrophils, these factors are stored in granules and released upon activation during degranulation. These factors could be also secreted in a neutrophil-derived microparticle-dependent fashion. Neutrophils exhibit a unique property to produce neutrophil extracellular traps (NETs) composed of decondensed chromatin and granular proteins to catch and kill bacteria. Neutrophil-released factors are efficient in inactivation and elimination of pathogens through oxidation-dependent or independent damage of bacterial cells, inactivation and neutralization of virulence factors and other mechanisms. However, in chronic atherosclerosis-associated inflammation, protective function of neutrophils could be impaired and misdirected against own cells. This could lead to deleterious effects and progressive vascular injury. In atherogenesis, a pathogenic role of neutrophils could be especially seen in early stages associated with endothelial dysfunction and induction of vascular inflammation and in late atherosclerosis associated with plaque rupture and atherothrombosis. Assuming a prominent impact of neutrophils in cardiovascular pathology, developing therapeutic strategies targeting neutrophil-specific antigens could have a promising clinical potential. PMID:26551083

  4. Review of the neutrophil response to Bordetella pertussis infection.

    PubMed

    Eby, Joshua C; Hoffman, Casandra L; Gonyar, Laura A; Hewlett, Erik L

    2015-12-01

    The nature and timing of the neutrophil response to infection with Bordetella pertussis is influenced by multiple virulence factors expressed by the bacterium. After inoculation of the host airway, the recruitment of neutrophils signaled by B. pertussis lipooligosaccharide (LOS) is suppressed by pertussis toxin (PTX). Over the next week, the combined activities of PTX, LOS and adenylate cyclase toxin (ACT) result in production of cytokines that generate an IL-17 response, promoting neutrophil recruitment which peaks at 10-14 days after inoculation in mice. Arriving at the site of infection, neutrophils encounter the powerful local inhibitory activity of ACT, in conjunction with filamentous hemagglutinin. With the help of antibodies, neutrophils contribute to clearance of B. pertussis, but only after 28-35 days in a naïve mouse. Studies of the lasting, antigen-specific IL-17 response to infection in mice and baboons has led to progress in vaccine development and understanding of pathogenesis. Questions remain about the mediators that coordinate neutrophil recruitment and the mechanisms by which neutrophils overcome B. pertussis virulence factors. PMID:26432818

  5. Blocking neutrophil integrin activation prevents ischemia–reperfusion injury

    PubMed Central

    Yago, Tadayuki; Petrich, Brian G.; Zhang, Nan; Liu, Zhenghui; Shao, Bojing; Ginsberg, Mark H.

    2015-01-01

    Neutrophil recruitment, mediated by β2 integrins, combats pyogenic infections but also plays a key role in ischemia–reperfusion injury and other inflammatory disorders. Talin induces allosteric rearrangements in integrins that increase affinity for ligands (activation). Talin also links integrins to actin and other proteins that enable formation of adhesions. Structural studies have identified a talin1 mutant (L325R) that perturbs activation without impairing talin’s capacity to link integrins to actin and other proteins. Here, we found that mice engineered to express only talin1(L325R) in myeloid cells were protected from renal ischemia–reperfusion injury. Dissection of neutrophil function in vitro and in vivo revealed that talin1(L325R) neutrophils had markedly impaired chemokine-induced, β2 integrin–mediated arrest, spreading, and migration. Surprisingly, talin1(L325R) neutrophils exhibited normal selectin-induced, β2 integrin–mediated slow rolling, in sharp contrast to the defective slow rolling of neutrophils lacking talin1 or expressing a talin1 mutant (W359A) that blocks talin interaction with integrins. These studies reveal the importance of talin-mediated activation of integrins for renal ischemia–reperfusion injury. They further show that neutrophil arrest requires talin recruitment to and activation of integrins. However, although neutrophil slow rolling requires talin recruitment to integrins, talin-mediated integrin activation is dispensable. PMID:26169939

  6. Tumor-Associated Macrophages and Neutrophils in Tumor Microenvironment

    PubMed Central

    Kim, Jaehong; Bae, Jong-Sup

    2016-01-01

    Distinct tumor microenvironment forms in each progression step of cancer and has diverse capacities to induce both adverse and beneficial consequences for tumorigenesis. It is now known that immune cells can be activated to favor tumor growth and progression, most probably influenced by the tumor microenvironment. Tumor-associated macrophages and tumor-associated neutrophils can exert protumoral functions, enhancing tumor cell invasion and metastasis, angiogenesis, and extracellular matrix remodeling, while inhibiting the antitumoral immune surveillance. Considering that neutrophils in inflammatory environments recruit macrophages and that recruited macrophages affect neutrophil functions, there may be various degrees of interaction between tumor-associated macrophages and tumor-associated neutrophils. Platelets also play an important role in the recruitment and regulation of monocytic and granulocytic cells in the tumor tissues, suggesting that platelet function may be essential for generation of tumor-associated macrophages and tumor-associated neutrophils. In this review, we will explore the biology of tumor-associated macrophages and tumor-associated neutrophils and their possible interactions in the tumor microenvironment. Special attention will be given to the recruitment and activation of these tumor-associated cells and to the roles they play in maintenance of the tumor microenvironment and progression of tumors. PMID:26966341

  7. Dimethylfumarate Impairs Neutrophil Functions.

    PubMed

    Müller, Susen; Behnen, Martina; Bieber, Katja; Möller, Sonja; Hellberg, Lars; Witte, Mareike; Hänsel, Martin; Zillikens, Detlef; Solbach, Werner; Laskay, Tamás; Ludwig, Ralf J

    2016-01-01

    Host defense against pathogens relies on neutrophil activation. Inadequate neutrophil activation is often associated with chronic inflammatory diseases. Neutrophils also constitute a significant portion of infiltrating cells in chronic inflammatory diseases, for example, psoriasis and multiple sclerosis. Fumarates improve the latter diseases, which so far has been attributed to the effects on lymphocytes and dendritic cells. Here, we focused on the effects of dimethylfumarate (DMF) on neutrophils. In vitro, DMF inhibited neutrophil activation, including changes in surface marker expression, reactive oxygen species production, formation of neutrophil extracellular traps, and migration. Phagocytic ability and autoantibody-induced, neutrophil-dependent tissue injury ex vivo was also impaired by DMF. Regarding the mode of action, DMF modulates-in a stimulus-dependent manner-neutrophil activation using the phosphoinositide 3-kinase/Akt-p38 mitogen-activated protein kinase and extracellular signal-regulated kinase 1/2 pathways. For in vivo validation, mouse models of epidermolysis bullosa acquisita, an organ-specific autoimmune disease caused by autoantibodies to type VII collagen, were employed. In the presence of DMF, blistering induced by injection of anti-type VII collagen antibodies into mice was significantly impaired. DMF treatment of mice with clinically already-manifested epidermolysis bullosa acquisita led to disease improvement. Collectively, we demonstrate a profound inhibitory activity of DMF on neutrophil functions. These findings encourage wider use of DMF in patients with neutrophil-mediated diseases. PMID:26763431

  8. ISOLATION OF MOUSE NEUTROPHILS

    PubMed Central

    Swamydas, Muthulekha; Luo, Yi; Dorf, Martin E.; Lionakis, Michail S.

    2015-01-01

    Neutrophils represent the first line of defense against bacterial and fungal pathogens. Indeed, patients with inherited and acquired qualitative and quantitative neutrophil defects are at high risk for developing bacterial and fungal infections and suffering adverse outcomes from these infections. Therefore, research aiming at defining the molecular factors that modulate neutrophil effector function under homeostatic conditions and during infection is essential for devising strategies to augment neutrophil function and improve the outcome of infected individuals. This unit describes a reproducible density gradient centrifugation-based protocol that can be applied in any laboratory to harvest large numbers of highly enriched and highly viable neutrophils from the bone marrow of mice both at the steady state and following infection with Candida albicans as described in UNIT 19.6. In another protocol, we also present a method that combines gentle enzymatic tissue digestion with a positive immunomagnetic selection technique or Fluorescence-activated cell sorting (FACS) to harvest highly pure and highly viable preparations of neutrophils directly from mouse tissues such as the kidney, the liver or the spleen. Finally, methods for isolating neutrophils from mouse peritoneal fluid and peripheral blood are included. Mouse neutrophils isolated by these protocols can be used for examining several aspects of cellular function ex vivo including pathogen binding, phagocytosis and killing, neutrophil chemotaxis, oxidative burst, degranulation and cytokine production, and for performing neutrophil adoptive transfer experiments. PMID:26237011

  9. Salmonella Transiently Reside in Luminal Neutrophils in the Inflamed Gut

    PubMed Central

    Loetscher, Yvonne; Wieser, Andreas; Lengefeld, Jette; Kaiser, Patrick; Schubert, Sören; Heikenwalder, Mathias; Hardt, Wolf-Dietrich; Stecher, Bärbel

    2012-01-01

    Background Enteric pathogens need to grow efficiently in the gut lumen in order to cause disease and ensure transmission. The interior of the gut forms a complex environment comprising the mucosal surface area and the inner gut lumen with epithelial cell debris and food particles. Recruitment of neutrophils to the intestinal lumen is a hallmark of non-typhoidal Salmonella enterica infections in humans. Here, we analyzed the interaction of gut luminal neutrophils with S. enterica serovar Typhimurium (S. Tm) in a mouse colitis model. Results Upon S. Tmwt infection, neutrophils transmigrate across the mucosa into the intestinal lumen. We detected a majority of pathogens associated with luminal neutrophils 20 hours after infection. Neutrophils are viable and actively engulf S. Tm, as demonstrated by live microscopy. Using S. Tm mutant strains defective in tissue invasion we show that pathogens are mostly taken up in the gut lumen at the epithelial barrier by luminal neutrophils. In these luminal neutrophils, S. Tm induces expression of genes typically required for its intracellular lifestyle such as siderophore production iroBCDE and the Salmonella pathogenicity island 2 encoded type three secretion system (TTSS-2). This shows that S. Tm at least transiently survives and responds to engulfment by gut luminal neutrophils. Gentamicin protection experiments suggest that the life-span of luminal neutrophils is limited and that S. Tm is subsequently released into the gut lumen. This “fast cycling” through the intracellular compartment of gut luminal neutrophils would explain the high fraction of TTSS-2 and iroBCDE expressing intra- and extracellular bacteria in the lumen of the infected gut. Conclusion In conclusion, live neutrophils recruited during acute S. Tm colitis engulf pathogens in the gut lumen and may thus actively engage in shaping the environment of pathogens and commensals in the inflamed gut. PMID:22493718

  10. Major neutrophil functions subverted by Porphyromonas gingivalis

    PubMed Central

    Olsen, Ingar; Hajishengallis, George

    2016-01-01

    Polymorphonuclear leukocytes (neutrophils) constitute an integrated component of the innate host defense in the gingival sulcus/periodontal pocket. However, the keystone periodontal pathogen Porphyromonas gingivalis has in the course of evolution developed a number of capacities to subvert this defense to its own advantage. The present review describes the major mechanisms that P. gingivalis uses to subvert neutrophil homeostasis, such as impaired recruitment and chemotaxis, resistance to granule-derived antimicrobial agents and to the oxidative burst, inhibition of phagocytic killing while promoting a nutritionally favorable inflammatory response, and delay of neutrophil apoptosis. Studies in animal models have shown that at least some of these mechanisms promote the dysbiotic transformation of the periodontal polymicrobial community, thereby leading to inflammation and bone loss. It is apparent that neutrophil–P. gingivalis interactions and subversion of innate immunity are key contributing factors to the pathogenesis of periodontal disease. PMID:26993626

  11. Neutrophilic dermatoses in children.

    PubMed

    Berk, David R; Bayliss, Susan J

    2008-01-01

    The neutrophilic dermatoses are rare disorders, especially in children, and are characterized by neutrophilic infiltrates in the skin and less commonly in extracutaneous tissue. The neutrophilic dermatoses share similar clinical appearances and associated conditions, including inflammatory bowel disease, malignancies, and medications. Overlap forms of disease demonstrating features of multiple neutrophilic dermatoses may be seen. The manuscript attempts to provide an up-to-date review of (i) classical neutrophilic dermatoses, focusing on distinctive features in children and (ii) neutrophilic dermatoses which may largely be pediatric or genodermatosis-associated (Majeed, SAPHO [synovitis, severe acne, sterile palmoplantar pustulosis, hyperostosis, and osteitis] syndrome, PAPA (pyogenic sterile arthritis, pyoderma gangrenosum, and acne), PFAPA (periodic fever with aphthous stomatitis, pharyngitis, and cervical adenopathy), and other periodic fever syndromes, and congenital erosive and vesicular dermatosis healing with reticulated supple scarring). PMID:18950391

  12. Blocking neutrophil diapedesis prevents hemorrhage during thrombocytopenia.

    PubMed

    Hillgruber, Carina; Pöppelmann, Birgit; Weishaupt, Carsten; Steingräber, Annika Kathrin; Wessel, Florian; Berdel, Wolfgang E; Gessner, J Engelbert; Ho-Tin-Noé, Benoît; Vestweber, Dietmar; Goerge, Tobias

    2015-07-27

    Spontaneous organ hemorrhage is the major complication in thrombocytopenia with a potential fatal outcome. However, the exact mechanisms regulating vascular integrity are still unknown. Here, we demonstrate that neutrophils recruited to inflammatory sites are the cellular culprits inducing thrombocytopenic tissue hemorrhage. Exposure of thrombocytopenic mice to UVB light provokes cutaneous petechial bleeding. This phenomenon is also observed in immune-thrombocytopenic patients when tested for UVB tolerance. Mechanistically, we show, analyzing several inflammatory models, that it is neutrophil diapedesis through the endothelial barrier that is responsible for the bleeding defect. First, bleeding is triggered by neutrophil-mediated mechanisms, which act downstream of capturing, adhesion, and crawling on the blood vessel wall and require Gαi signaling in neutrophils. Second, mutating Y731 in the cytoplasmic tail of VE-cadherin, known to selectively affect leukocyte diapedesis, but not the induction of vascular permeability, attenuates bleeding. Third, and in line with this, simply destabilizing endothelial junctions by histamine did not trigger bleeding. We conclude that specifically targeting neutrophil diapedesis through the endothelial barrier may represent a new therapeutic avenue to prevent fatal bleeding in immune-thrombocytopenic patients. PMID:26169941

  13. Employee recruitment.

    PubMed

    Breaugh, James A

    2013-01-01

    The way an organization recruits can influence the type of employees it hires, how they perform, and their retention rate. This article provides a selective review of research that has addressed recruitment targeting, recruitment methods, the recruitment message, recruiters, the organizational site visit, the job offer, and the timing of recruitment actions. These and other topics (e.g., the job applicant's perspective) are discussed in terms of their potential influence on prehire (e.g., the quality of job applicants) and posthire (e.g., new employee retention) recruitment outcomes. In reviewing research, attention is given to the current state of scientific knowledge, limitations of previous research, and important issues meriting future investigation. PMID:23121331

  14. Immunoreceptors on neutrophils.

    PubMed

    van Rees, Dieke J; Szilagyi, Katka; Kuijpers, Taco W; Matlung, Hanke L; van den Berg, Timo K

    2016-04-01

    Neutrophils play a critical role in the host defense against infection, and they are able to perform a variety of effector mechanisms for this purpose. However, there are also a number of pathological conditions, including autoimmunity and cancer, in which the activities of neutrophils can be harmful to the host. Thus the activities of neutrophils need to be tightly controlled. As in the case of other immune cells, many of the neutrophil effector functions are regulated by a series of immunoreceptors on the plasma membrane. Here, we review what is currently known about the functions of the various individual immunoreceptors and their signaling in neutrophils. While these immunoreceptors allow for the recognition of a diverse range of extracellular ligands, such as cell surface structures (like proteins, glycans and lipids) and extracellular matrix components, they commonly signal via conserved ITAM or ITIM motifs and their associated downstream pathways that depend on the phosphorylation of tyrosine residues in proteins and/or inositol lipids. This allows for a balanced homeostatic regulation of neutrophil effector functions. Given the number of available immunoreceptors and their fundamental importance for neutrophil behavior, it is perhaps not surprising that pathogens have evolved means to evade immune responses through some of these pathways. Inversely, some of these receptors evolved to specifically recognize these pathogens. Finally, some interactions mediated by immunoreceptors in neutrophils have been identified as promising targets for therapeutic intervention. PMID:26976825

  15. Neutrophils in cancer.

    PubMed

    Treffers, Louise W; Hiemstra, Ida H; Kuijpers, Taco W; van den Berg, Timo K; Matlung, Hanke L

    2016-09-01

    Neutrophils play an important role in cancer. This does not only relate to the well-established prognostic value of the presence of neutrophils, either in the blood or in tumor tissue, in the context of cancer progression or for the monitoring of therapy, but also to their active role in the progression of cancer. In the current review, we describe what is known in general about the role of neutrophils in cancer. What is emerging is a complex, rather heterogeneous picture with both pro- and anti-tumorigenic roles, which apparently differs with cancer type and disease stage. Furthermore, we will discuss the well-known role of neutrophils as myeloid-derived suppressor cells (MDSC), and also on the role of neutrophils as important effector cells during antibody therapy in cancer. It is clear that neutrophils contribute substantially to cancer progression in multiple ways, and this includes both direct effects on the cancer cells and indirect effect on the tumor microenvironment. While in many cases neutrophils have been shown to promote tumor progression, for instance by acting as MDSC, there are also protective effects, particularly when antibody immunotherapy is performed. A better understanding of the role of neutrophils is likely to provide opportunities for immunomodulation and for improving the treatment of cancer patients. PMID:27558343

  16. Myeloperoxidase Stimulates Neutrophil Degranulation.

    PubMed

    Grigorieva, D V; Gorudko, I V; Sokolov, A V; Kostevich, V A; Vasilyev, V B; Cherenkevich, S N; Panasenko, O M

    2016-08-01

    Myeloperoxidase, heme enzyme of azurophilic granules in neutrophils, is released into the extracellular space in the inflammation foci. In neutrophils, it stimulates a dose-dependent release of lactoferrin (a protein of specific granules), lysozyme (a protein of specific and azurophilic granules), and elastase (a protein of azurophilic granules). 4-Aminobenzoic acid hydrazide, a potent inhibitor of peroxidase activity of myeloperoxidase, produced no effect on neutrophil degranulation. Using signal transduction inhibitors (genistein, methoxyverapamil, wortmannin, and NiCl2), we demonstrated that myeloperoxidase-induced degranulation of neutrophils resulted from enzyme interaction with the plasma membrane and depends on activation of tyrosine kinases, phosphatidylinositol 3-kinases (PI3K), and calcium signaling. Myeloperoxidase modified by oxidative/halogenation stress (chlorinated and monomeric forms of the enzyme) lost the potency to activate neutrophil degranulation. PMID:27597056

  17. [Neutrophilic functional heterogeneity].

    PubMed

    2006-02-01

    Blood neutrophilic functional heterogeneity is under discussion. The neutrophils of one subpopulation, namely killer neutrophils (Nk), potential phagocytes, constitute a marginal pool and a part of the circulating pool, intensively produce active oxygen forms (AOF) and they are adherent to the substrate. The neutrophils of another subpopulation, cager neutrophils (Nc), seem to perform a transport function of delivering foreign particles to the competent organs, to form about half of the circulating pool, to produce APC to a lesser extent, exclusively for self-defense and, probably, in usual conditions, to fail to interact with substrate. Analysis of the experimental findings suggests that the phylogenetic age of Nk is older than that of Nc and Nk has predominantly a tendency to spontaneous apoptosis under physiological conditions. PMID:16610631

  18. Intravenous immunoglobulins modulate neutrophil activation and vascular injury through FcγRIII and SHP-1

    PubMed Central

    Jang, Jung-Eun; Hidalgo, Andrés; Frenette, Paul S.

    2012-01-01

    Rationale Intravascular neutrophil recruitment and activation are a key pathogenic factor that contributes to vascular injury. Intravenous immunoglobulin (IVIG) has been shown to have a beneficial effect in systemic inflammatory disorders; however, the mechanisms underlying IVIG’s inhibitory effect on neutrophil recruitment and activation are not understood. Objective We studied the mechanisms by which IVIG exerts protection from neutrophil-mediated acute vascular injury. Methods and Results We examined neutrophil behavior in response to IVIG in vivo using real time intravital microscopy. We found that an antibody that blocks both FcγRIII and its inhibitory receptor counterpart, FcγRIIB, abrogated the inhibitory effect of IVIG on leukocyte recruitment and heterotypic RBC interactions with adherent leukocytes in wild-type mice. In the context of sickle cell disease, the blockade of both FcγRIIB and III abrogated the protective effect of IVIG on acute vaso-occlusive crisis caused by neutrophil recruitment and activation. Analysis of FcγRIIB- and FcγRIII-deficient mice revealed the predominant expression of FcγRIII on circulating neutrophils. FcγRIII mediated IVIG-triggered inhibition of leukocyte recruitment, circulating RBC capture, and enhanced Mac-1 activity, whereas FcγRIIB was dispensable. In addition, FcγRIII-induced IVIG anti-inflammatory activity in neutrophils was mediated by recruitment of Src homology 2 (SH2)-containing tyrosine phosphatase-1 (SHP-1). Indeed, the protective effect of IVIG on leukocyte recruitment and activation was abrogated in SHP-1-mutant mice. Conclusions FcγRIII, a classical activating receptor, has an unexpected inhibitory role on neutrophil adhesion and activation via recruitment of SHP-1 in response to IVIG. Our results identify SHP-1 as a therapeutic target in neutrophil-mediated vascular injury. PMID:22415018

  19. Neutrophil kinetics in man.

    PubMed Central

    Dancey, J T; Deubelbeiss, K A; Harker, L A; Finch, C A

    1976-01-01

    A method has been developed for measuring neutrophil cellularity in normal human bone marrow, in which the neutrophil-erythroid ratio was determined from marrow sections and marrow normoblasts were estimated by the erythron iron turnover. Neutrophil maturational categories, defined by morphologic criteria, were supported by autoradiographs of marrow flashed-labeled with 3H-thymidine. Correction for multiple counting error was empirically derived by counting serial sections through cells of each maturational category. The normal neutrophil-erythroid ratio in 13 normal human subjects was 1.5 +/- 0.07. The mean number of normoblasts in the same subjects was estimated to be 5.07 +/- 0.84 X 10(9) cells/kg. Total marrow neutrophils (X 10(9) cells/kg) were 7.70 +/- 1.20, the postmitotic pool (metamyelocytes, bands, and segmented forms) was 5.59 +/- 0.90 and the mitotic pool (promyelocytes + myelocytes) was 2.11 +/- 0.36. Marrow neutrophil ("total") production has been determined from the number of neutrophils comprising the postmitotic marrow pool divided by their transit time Transit time was derived from the appearance in circulating neutrophils of injected 3H-thymidine. The postmitotic pool comprised 5.59 +/- 0.90 X 10(9) neutrophils/kg, and the transit time was 6.60 +/- 0.03 days. From these data marrow neutrophil production was calculated to be 0.85 X 10(9) cells/kg per day. Effective production, measured as the turnover of circulating neutrophils labeled with 3H-thymidine, was 0.87 +/- 0.13 X 10(9) cells/kg per day. This value correlated well with the calculation of marrow neutrophil production. A larger turnover of 1.62 +/- 0.46 X 10(9) cells/kg per day was obtained when diisopropylfluorophosphate-32P was used to label circulating neutrophils. Studies using isologous cells doubly labeled with 3H-thymidine and diisopropylfluorophosphate-32P demonstrated a lower recovery and shorter t1/2 of the 32P label. Images PMID:956397

  20. Neutrophil Elastase Modulates Cytokine Expression

    PubMed Central

    Benabid, Rym; Wartelle, Julien; Malleret, Laurette; Guyot, Nicolas; Gangloff, Sophie; Lebargy, François; Belaaouaj, Azzaq

    2012-01-01

    There is accumulating evidence that following bacterial infection, the massive recruitment and activation of the phagocytes, neutrophils, is accompanied with the extracellular release of active neutrophil elastase (NE), a potent serine protease. Using NE-deficient mice in a clinically relevant model of Pseudomonas aeruginosa-induced pneumonia, we provide compelling in vivo evidence that the absence of NE was associated with decreased protein and transcript levels of the proinflammatory cytokines TNF-α, MIP-2, and IL-6 in the lungs, coinciding with increased mortality of mutant mice to infection. The implication of NE in the induction of cytokine expression involved at least in part Toll-like receptor 4 (TLR-4). These findings were further confirmed following exposure of cultured macrophages to purified NE. Together, our data suggest strongly for the first time that NE not only plays a direct antibacterial role as it has been previously reported, but released active enzyme can also modulate cytokine expression, which contributes to host protection against P. aeruginosa. In light of our findings, the long held view that considers NE as a prime suspect in P. aeruginosa-associated diseases will need to be carefully reassessed. Also, therapeutic strategies aiming at NE inhibition should take into account the physiologic roles of the enzyme. PMID:22927440

  1. Vestibular recruitment

    NASA Technical Reports Server (NTRS)

    Tsemakhov, S. G.

    1980-01-01

    Vestibular recruitment is defined through the analysis of several references. It is concluded that vestibular recruitment is an objective phenomenon which manifests itself during the affection of the vestibular receptor and thus serves as a diagnostic tool during affection of the vestibular system.

  2. Resident recruitment.

    PubMed

    Longmaid, H Esterbrook

    2003-02-01

    This article has introduced the reader to the critical components of successful recruitment of radiology residents. With particular attention to the ACGME institutional and program requirements regarding resident recruitment, and an explanation of the support systems (ERAS and NRMP) currently available to those involved in applicant review and selection, the article has sought to delineate a sensible approach to recruitment. Successful recruiters have mastered the essentials of these programs and have learned to adapt the programs to their needs. As new program directors work with their departments' resident selection committees, they will identify the factors that faculty and current residents cite as most important in the successful selection of new residents. By structuring the application review process, exploiting the power of the ERAS, and crafting a purposeful and friendly interview process, radiology residency directors can find and recruit the residents who best match their programs. PMID:12585436

  3. Proteinase 3 contributes to transendothelial migration of NB1-positive neutrophils.

    PubMed

    Kuckleburg, Christopher J; Tilkens, Sarah B; Santoso, Sentot; Newman, Peter J

    2012-03-01

    Neutrophil transmigration requires the localization of neutrophils to endothelial cell junctions, in which receptor-ligand interactions and the action of serine proteases promote leukocyte diapedesis. NB1 (CD177) is a neutrophil-expressed surface molecule that has been reported to bind proteinase 3 (PR3), a serine protease released from activated neutrophils. PR3 has demonstrated proteolytic activity on a number of substrates, including extracellular matrix proteins, although its role in neutrophil transmigration is unknown. Recently, NB1 has been shown to be a heterophilic binding partner for the endothelial cell junctional protein, PECAM-1. Disrupting the interaction between NB1 and PECAM-1 significantly inhibits neutrophil transendothelial cell migration on endothelial cell monolayers. Because NB1 interacts with endothelial cell PECAM-1 at cell junctions where transmigration occurs, we considered that NB1-PR3 interactions may play a role in aiding neutrophil diapedesis. Blocking Abs targeting the heterophilic binding domain of PECAM-1 significantly inhibited transmigration of NB1-positive neutrophils through IL-1β-stimulated endothelial cell monolayers. PR3 expression and activity were significantly increased on NB1-positive neutrophils following transmigration, whereas neutrophils lacking NB1 demonstrated no increase in PR3. Finally, using selective serine protease inhibitors, we determined that PR3 activity facilitated transmigration of NB1-positive neutrophils under both static and flow conditions. These data demonstrate that PR3 contributes in the selective recruitment of the NB1-positive neutrophil population. PMID:22266279

  4. Neutrophil AKT2 regulates heterotypic cell-cell interactions during vascular inflammation.

    PubMed

    Li, Jing; Kim, Kyungho; Hahm, Eunsil; Molokie, Robert; Hay, Nissim; Gordeuk, Victor R; Du, Xiaoping; Cho, Jaehyung

    2014-04-01

    Interactions between platelets, leukocytes, and activated endothelial cells are important during microvascular occlusion; however, the regulatory mechanisms of these heterotypic cell-cell interactions remain unclear. Here, using intravital microscopy to evaluate mice lacking specific isoforms of the serine/threonine kinase AKT and bone marrow chimeras, we found that hematopoietic cell-associated AKT2 is important for neutrophil adhesion and crawling and neutrophil-platelet interactions on activated endothelial cells during TNF-α-induced venular inflammation. Studies with an AKT2-specific inhibitor and cells isolated from WT and Akt KO mice revealed that platelet- and neutrophil-associated AKT2 regulates heterotypic neutrophil-platelet aggregation under shear conditions. In particular, neutrophil AKT2 was critical for membrane translocation of αMβ2 integrin, β2-talin1 interaction, and intracellular Ca2+ mobilization. We found that the basal phosphorylation levels of AKT isoforms were markedly increased in neutrophils and platelets isolated from patients with sickle cell disease (SCD), an inherited hematological disorder associated with vascular inflammation and occlusion. AKT2 inhibition reduced heterotypic aggregation of neutrophils and platelets isolated from SCD patients and diminished neutrophil adhesion and neutrophil-platelet aggregation in SCD mice, thereby improving blood flow rates. Our results provide evidence that neutrophil AKT2 regulates αMβ2 integrin function and suggest that AKT2 is important for neutrophil recruitment and neutrophil-platelet interactions under thromboinflammatory conditions such as SCD. PMID:24642468

  5. Commensal microbiota stimulate systemic neutrophil migration through induction of serum amyloid A.

    PubMed

    Kanther, Michelle; Tomkovich, Sarah; Xiaolun, Sun; Grosser, Melinda R; Koo, Jaseol; Flynn, Edward J; Jobin, Christian; Rawls, John F

    2014-07-01

    Neutrophils serve critical roles in inflammatory responses to infection and injury, and mechanisms governing their activity represent attractive targets for controlling inflammation. The commensal microbiota is known to regulate the activity of neutrophils and other leucocytes in the intestine, but the systemic impact of the microbiota on neutrophils remains unknown. Here we utilized in vivo imaging in gnotobiotic zebrafish to reveal diverse effects of microbiota colonization on systemic neutrophil development and function. The presence of a microbiota resulted in increased neutrophil number and myeloperoxidase expression, and altered neutrophil localization and migratory behaviours. These effects of the microbiota on neutrophil homeostasis were accompanied by an increased recruitment of neutrophils to injury. Genetic analysis identified the microbiota-induced acute phase protein serum amyloid A (Saa) as a host factor mediating microbial stimulation of tissue-specific neutrophil migratory behaviours. In vitro studies revealed that zebrafish cells respond to Saa exposure by activating NF-κB, and that Saa-dependent neutrophil migration requires NF-κB-dependent gene expression. These results implicate the commensal microbiota as an important environmental factor regulating diverse aspects of systemic neutrophil development and function, and reveal a critical role for a Saa-NF-κB signalling axis in mediating neutrophil migratory responses. PMID:24373309

  6. Central role of neutrophil in the pathogenesis of severe acute pancreatitis

    PubMed Central

    Yang, Zhi-wen; Meng, Xiao-xiao; Xu, Ping

    2015-01-01

    Severe acute pancreatitis (SAP) is an acute abdominal disease with the strong systemic inflammatory response, and rapidly progresses from a local pancreatic damage into multiple organ dysfunction. For many decades, the contributions of neutrophils to the pathology of SAP were traditionally thought to be the chemokine and cytokine cascades that accompany inflammation. In this review, we focus mainly on those recently recognized aspects of neutrophils in SAP processes. First, emerging evidence suggests that therapeutic interventions targeting neutrophils significantly lower tissue damage and protect against the occurrence of pancreatitis. Second, trypsin activation promotes the initial neutrophils recruitment into local pancreas, and subsequently neutrophils infiltration in turn triggers trypsin production. Finally, neutrophils have the unique ability to release neutrophil extracellular traps even in the absence of pathogens. PMID:26249268

  7. Frontline Science: Splenic progenitors aid in maintaining high neutrophil numbers at sites of sterile chronic inflammation.

    PubMed

    Jhunjhunwala, Siddharth; Alvarez, David; Aresta-DaSilva, Stephanie; Tang, Katherine; Tang, Benjamin C; Greiner, Dale L; Newburger, Peter E; von Andrian, Ulrich H; Langer, Robert; Anderson, Daniel G

    2016-08-01

    Neutrophils are constantly generated from hematopoietic stem and progenitor cells in the bone marrow to maintain high numbers in circulation. A considerable number of neutrophils and their progenitors have been shown to be present in the spleen too; however, their exact role in this organ remains unclear. Herein, we sought to study the function of splenic neutrophils and their progenitors using a mouse model for sterile, peritoneal inflammation. In this microcapsule device implantation model, we show chronic neutrophil presence at implant sites, with recruitment from circulation as the primary mechanism for their prevalence in the peritoneal exudate. Furthermore, we demonstrate that progenitor populations in the spleen play a key role in maintaining elevated neutrophil numbers. Our results provide new insight into the role for splenic neutrophils and their progenitors and establish a model to study neutrophil function during sterile inflammation. PMID:26965635

  8. Central role of neutrophil in the pathogenesis of severe acute pancreatitis.

    PubMed

    Yang, Zhi-Wen; Meng, Xiao-Xiao; Xu, Ping

    2015-11-01

    Severe acute pancreatitis (SAP) is an acute abdominal disease with the strong systemic inflammatory response, and rapidly progresses from a local pancreatic damage into multiple organ dysfunction. For many decades, the contributions of neutrophils to the pathology of SAP were traditionally thought to be the chemokine and cytokine cascades that accompany inflammation. In this review, we focus mainly on those recently recognized aspects of neutrophils in SAP processes. First, emerging evidence suggests that therapeutic interventions targeting neutrophils significantly lower tissue damage and protect against the occurrence of pancreatitis. Second, trypsin activation promotes the initial neutrophils recruitment into local pancreas, and subsequently neutrophils infiltration in turn triggers trypsin production. Finally, neutrophils have the unique ability to release neutrophil extracellular traps even in the absence of pathogens. PMID:26249268

  9. EVALUATION OF ASSAYS FOR THE MEASUREMENT OF BOVINE NEUTROPHIL REACTIVE OXYGEN SPECIES.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    During mastitis and other bacterial-mediated diseases of cattle, neutrophils play a critical role in the host innate immune response to infection. Neutrophils are among the earliest leukocytes recruited to the site of infection and contribute to host innate immune defenses through their ability to ...

  10. Neutrophils in cystic fibrosis.

    PubMed

    Laval, Julie; Ralhan, Anjali; Hartl, Dominik

    2016-06-01

    Cystic fibrosis (CF) lung disease is characterized by chronic infection and inflammation. Among inflammatory cells, neutrophils represent the major cell population accumulating in the airways of CF patients. While neutrophils provide the first defensive cellular shield against bacterial and fungal pathogens, in chronic disease conditions such as CF these short-lived immune cells release their toxic granule contents that cause tissue remodeling and irreversible structural damage to the host. A variety of human and murine studies have analyzed neutrophils and their products in the context of CF, yet their precise functional role and therapeutic potential remain controversial and incompletely understood. Here, we summarize the current evidence in this field to shed light on the complex and multi-faceted role of neutrophils in CF lung disease. PMID:26854289

  11. Neutrophil biology: an update

    PubMed Central

    Kobayashi, Yoshiro

    2015-01-01

    Neutrophil extracellular traps (NETs) are involved in bacterial killing as well as autoimmunity, because NETs contain proteases, bactericidal peptides, DNA and ribonucleoprotein. NETs are formed via a novel type of cell death called NETosis. NETosis is distinct from apoptosis, but it resembles necrosis in that both membranes are not intact so that they allow intracellular proteins to leak outside of the cells. Removal of NETs and neutrophils undergoing NETosis by phagocytes and its subsequent response are not completely clarified, as compared with the response after removal of either apoptotic or necrotic neutrophils by phagocytes. How neutrophil density in peripheral blood is kept within a certain range is important for health and disease. Although the studies on severe congenital neutropenia and benign ethnic neutropenia have provided unbiased views on it, the studies are rather limited to human neutropenia, and mice with a mutation of mouse counterpart gene often fail to exhibit neutropenia. Degranulation plays a critical role in bactericidal action. The recent studies revealed that it is also involved in immunomodulation, pain control and estrous cycle control. N1 and N2 are representative of neutrophil subpopulations. The dichotomy holds true in patients or mice with severe trauma or cancer, providing the basis of differential roles of neutrophils in diseases. PMID:26600743

  12. Identification and characterization of VEGF-A-responsive neutrophils expressing CD49d, VEGFR1, and CXCR4 in mice and humans.

    PubMed

    Massena, Sara; Christoffersson, Gustaf; Vågesjö, Evelina; Seignez, Cédric; Gustafsson, Karin; Binet, François; Herrera Hidalgo, Carmen; Giraud, Antoine; Lomei, Jalal; Weström, Simone; Shibuya, Masabumi; Claesson-Welsh, Lena; Gerwins, Pär; Welsh, Michael; Kreuger, Johan; Phillipson, Mia

    2015-10-22

    Vascular endothelial growth factor A (VEGF-A) is upregulated during hypoxia and is the major regulator of angiogenesis. VEGF-A expression has also been found to recruit myeloid cells to ischemic tissues where they contribute to angiogenesis. This study investigates the mechanisms underlying neutrophil recruitment to VEGF-A as well as the characteristics of these neutrophils. A previously undefined circulating subset of neutrophils shown to be CD49d(+)VEGFR1(high)CXCR4(high) was identified in mice and humans. By using chimeric mice with impaired VEGF receptor 1 (VEGFR1) or VEGFR2 signaling (Flt-1tk(-/-), tsad(-/-)), we found that parallel activation of VEGFR1 on neutrophils and VEGFR2 on endothelial cells was required for VEGF-A-induced recruitment of circulating neutrophils to tissue. Intravital microscopy of mouse microcirculation revealed that neutrophil recruitment by VEGF-A versus by the chemokine macrophage inflammatory protein 2 (MIP-2 [CXCL2]) involved the same steps of the recruitment cascade but that an additional neutrophil integrin (eg, VLA-4 [CD49d/CD29]) played a crucial role in neutrophil crawling and emigration to VEGF-A. Isolated CD49d(+) neutrophils featured increased chemokinesis but not chemotaxis compared with CD49d(-) neutrophils in the presence of VEGF-A. Finally, by targeting the integrin α4 subunit (CD49d) in a transplantation-based angiogenesis model that used avascular pancreatic islets transplanted to striated muscle, we demonstrated that inhibiting the recruitment of circulating proangiogenic neutrophils to hypoxic tissue impairs vessel neoformation. Thus, angiogenesis can be modulated by targeting cell-surface receptors specifically involved in VEGF-A-dependent recruitment of proangiogenic neutrophils without compromising recruitment of the neutrophil population involved in the immune response to pathogens. PMID:26286848

  13. Identification and characterization of VEGF-A–responsive neutrophils expressing CD49d, VEGFR1, and CXCR4 in mice and humans

    PubMed Central

    Massena, Sara; Christoffersson, Gustaf; Vågesjö, Evelina; Seignez, Cédric; Gustafsson, Karin; Binet, François; Herrera Hidalgo, Carmen; Giraud, Antoine; Lomei, Jalal; Weström, Simone; Shibuya, Masabumi; Claesson-Welsh, Lena; Gerwins, Pär; Welsh, Michael; Kreuger, Johan

    2015-01-01

    Vascular endothelial growth factor A (VEGF-A) is upregulated during hypoxia and is the major regulator of angiogenesis. VEGF-A expression has also been found to recruit myeloid cells to ischemic tissues where they contribute to angiogenesis. This study investigates the mechanisms underlying neutrophil recruitment to VEGF-A as well as the characteristics of these neutrophils. A previously undefined circulating subset of neutrophils shown to be CD49d+VEGFR1highCXCR4high was identified in mice and humans. By using chimeric mice with impaired VEGF receptor 1 (VEGFR1) or VEGFR2 signaling (Flt-1tk−/−, tsad−/−), we found that parallel activation of VEGFR1 on neutrophils and VEGFR2 on endothelial cells was required for VEGF-A-induced recruitment of circulating neutrophils to tissue. Intravital microscopy of mouse microcirculation revealed that neutrophil recruitment by VEGF-A versus by the chemokine macrophage inflammatory protein 2 (MIP-2 [CXCL2]) involved the same steps of the recruitment cascade but that an additional neutrophil integrin (eg, VLA-4 [CD49d/CD29]) played a crucial role in neutrophil crawling and emigration to VEGF-A. Isolated CD49d+ neutrophils featured increased chemokinesis but not chemotaxis compared with CD49d– neutrophils in the presence of VEGF-A. Finally, by targeting the integrin α4 subunit (CD49d) in a transplantation-based angiogenesis model that used avascular pancreatic islets transplanted to striated muscle, we demonstrated that inhibiting the recruitment of circulating proangiogenic neutrophils to hypoxic tissue impairs vessel neoformation. Thus, angiogenesis can be modulated by targeting cell-surface receptors specifically involved in VEGF-A-dependent recruitment of proangiogenic neutrophils without compromising recruitment of the neutrophil population involved in the immune response to pathogens. PMID:26286848

  14. The Multifaceted Roles Neutrophils Play in the Tumor Microenvironment.

    PubMed

    Sionov, Ronit Vogt; Fridlender, Zvi G; Granot, Zvi

    2015-12-01

    Neutrophils are myeloid cells that constitute 50-70 % of all white blood cells in the human circulation. Traditionally, neutrophils are viewed as the first line of defense against infections and as a major component of the inflammatory process. In addition, accumulating evidence suggest that neutrophils may also play a key role in multiple aspects of cancer biology. The possible involvement of neutrophils in cancer prevention and promotion was already suggested more than half a century ago, however, despite being the major component of the immune system, their contribution has often been overshadowed by other immune components such as lymphocytes and macrophages. Neutrophils seem to have conflicting functions in cancer and can be classified into anti-tumor (N1) and pro-tumor (N2) sub-populations. The aim of this review is to discuss the varying nature of neutrophil function in the cancer microenvironment with a specific emphasis on the mechanisms that regulate neutrophil mobilization, recruitment and activation. PMID:24895166

  15. Matters of life and death. How neutrophils die or survive along NET release and is "NETosis" = necroptosis?

    PubMed

    Desai, Jyaysi; Mulay, Shrikant R; Nakazawa, Daigo; Anders, Hans-Joachim

    2016-06-01

    Neutrophil extracellular trap (NET) formation is a hallmark of many disorders that involve neutrophil recruitment, tissue damage, and inflammation. As NET formation is often associated with neutrophil death, the term "NETosis" has become popular. Upon discovery that neutrophils may survive NET release, apparent misnomers, such as "vital NETosis," have been proposed. Meanwhile, it has become obvious that certain stimuli can trigger neutrophil necroptosis, a process associated with NET-like chromatin release. Here, we discuss the relationship between NET release and neutrophil death in view highlighting that many assays used in the field do not properly distinguish between the two. An updated nomenclature is needed replacing the term "NETosis" to meet the growing variety of settings leading to chromatin release with and without neutrophil death. Dissecting which triggers of NET release involve which signaling pathway will help to define drugable molecular targets that inhibit NET release and/or neutrophil necrosis in specific disorders. PMID:27048811

  16. Lung inflammation promotes metastasis through neutrophil protease-mediated degradation of Tsp-1

    PubMed Central

    El Rayes, Tina; Catena, Raúl; Lee, Sharrell; Stawowczyk, Marcin; Joshi, Natasha; Fischbach, Claudia; Powell, Charles A.; Dannenberg, Andrew J.; Altorki, Nasser K.; Gao, Dingcheng; Mittal, Vivek

    2015-01-01

    Inflammation is inextricably associated with primary tumor progression. However, the contribution of inflammation to tumor outgrowth in metastatic organs has remained underexplored. Here, we show that extrinsic inflammation in the lungs leads to the recruitment of bone marrow-derived neutrophils, which degranulate azurophilic granules to release the Ser proteases, elastase and cathepsin G, resulting in the proteolytic destruction of the antitumorigenic factor thrombospondin-1 (Tsp-1). Genetic ablation of these neutrophil proteases protected Tsp-1 from degradation and suppressed lung metastasis. These results provide mechanistic insights into the contribution of inflammatory neutrophils to metastasis and highlight the unique neutrophil protease–Tsp-1 axis as a potential antimetastatic therapeutic target. PMID:26668367

  17. Effects of CXC chemokines on neutrophil activation and sequestration in hepatic vasculature.

    PubMed

    Bajt, M L; Farhood, A; Jaeschke, H

    2001-11-01

    The initiating step of neutrophil-induced cytotoxicity in the liver is the recruitment of these phagocytes into sinusoids. The aim of our study was to compare the efficacy of systemic exposure with individual inflammatory mediators on neutrophil activation and sequestration in the hepatic vasculature of C3Heb/FeJ mice as assessed by flow cytometry and histochemistry, respectively. The CXC chemokine macrophage inflammatory protein-2 (MIP-2; 20 microg/kg) induced a time-dependent upregulation of Mac-1 (318% at 4 h) and shedding of L-selectin (41% at 4 h). MIP-2 treatment caused a temporary increase of sinusoidal neutrophil accumulation at 0.5 h [97 +/- 6 polymorphonuclear leukocytes (PMN)/50 high-power fields (HPF)], which declined to baseline (8 +/- 2) at 4 h. The CXC chemokine KC was largely ineffective in activating neutrophils or recruiting them into the liver. Cytokines (tumor necrosis factor-alpha and interleukin-1alpha) and cobra venom factor substantially increased Mac-1 expression and L-selectin shedding on neutrophils and caused stable sinusoidal neutrophil accumulation (170-220 PMN/50 HPF). Only cytokines induced venular neutrophil margination. Thus CXC chemokines in circulation are less effective than cytokines or complement in activation of neutrophils and their recruitment into the hepatic vasculature in vivo. PMID:11668027

  18. Neutrophils Self-Regulate Immune Complex-Mediated Cutaneous Inflammation through CXCL2.

    PubMed

    Li, Jackson LiangYao; Lim, Chun Hwee; Tay, Fen Wei; Goh, Chi Ching; Devi, Sapna; Malleret, Benoit; Lee, Bernett; Bakocevic, Nadja; Chong, Shu Zhen; Evrard, Maximilien; Tanizaki, Hideaki; Lim, Hwee Ying; Russell, Bruce; Renia, Laurent; Zolezzi, Francesca; Poidinger, Michael; Angeli, Veronique; St John, Ashley L; Harris, John E; Tey, Hong Liang; Tan, Suet Mien; Kabashima, Kenji; Weninger, Wolfgang; Larbi, Anis; Ng, Lai Guan

    2016-02-01

    Deposition of immune complexes (ICs) in tissues triggers acute inflammatory pathology characterized by massive neutrophil influx leading to edema and hemorrhage, and is especially associated with vasculitis of the skin, but the mechanisms that regulate this type III hypersensitivity process remain poorly understood. Here, using a combination of multiphoton intravital microscopy and genomic approaches, we re-examined the cutaneous reverse passive Arthus reaction and observed that IC-activated neutrophils underwent transmigration, triggered further IC formation, and transported these ICs into the interstitium, whereas neutrophil depletion drastically reduced IC formation and ameliorated vascular leakage in vivo. Thereafter, we show that these neutrophils expressed high levels of CXCL2, which further amplified neutrophil recruitment and activation in an autocrine and/or paracrine manner. Notably, CXCL1 expression was restricted to tissue-resident cell types, but IC-activated neutrophils may also indirectly, via soluble factors, modulate macrophage CXCL1 expression. Consistent with their distinct cellular origins and localization, only neutralization of CXCL2 but not CXCL1 in the interstitium effectively reduced neutrophil recruitment. In summary, our study establishes that neutrophils are able to self-regulate their own recruitment and responses during IC-mediated inflammation through a CXCL2-driven feed forward loop. PMID:26802238

  19. Inactivation of heparan sulfate 2-O-sulfotransferase accentuates neutrophil infiltration during acute inflammation in mice

    PubMed Central

    Axelsson, Jakob; Xu, Ding; Na Kang, Bit; Nussbacher, Julia K.; Handel, Tracy M.; Ley, Klaus; Sriramarao, P.

    2012-01-01

    Neutrophil recruitment and extravasation at sites of inflammation provide a mechanism for host defense. We showed previously that heparan sulfate, a type of sulfated glycosaminoglycan, facilitates neutrophil recruitment based on the reduction of neutrophil infiltration in mice in which the overall sulfation of the chains was reduced by selective inactivation of N-acetylglucosamine N-deacetylase-N-sulfotransferase (Ndst1) in endothelial cells. Here we show that inactivation of uronyl 2-O-sulfotransferase in endothelial cells (Hs2st), an enzyme that acts downstream from Ndst1, results in enhanced neutrophil recruitment in several models of acute inflammation. Enhanced neutrophil infiltration resulted in part from reduced rolling velocity under flow both in vivo and in vitro, which correlated with stronger binding of neutrophil L-selectin to mutant endothelial cells. Hs2st-deficient endothelial cells also displayed a striking increase in binding of IL-8 and macrophage inflammatory protein-2. The enhanced binding of these mediators of neutrophil recruitment resulted from a change in heparan sulfate structure caused by increased N-sulfation and 6-O-sulfation of glucosamine units in response to the decrease in 2-O-sulfation of uronic acid residues. This gain-of-function phenotype provides formidable evidence demonstrating the importance of endothelial heparan sulfate in inflammation and suggests a novel enzyme target for enhancing the innate immune response. PMID:22791291

  20. The hepatic inflammatory response after acetaminophen overdose: role of neutrophils.

    PubMed

    Lawson, J A; Farhood, A; Hopper, R D; Bajt, M L; Jaeschke, H

    2000-04-01

    Acetaminophen overdose induces severe liver injury and hepatic failure. There is evidence that inflammatory cells may be involved in the pathophysiology. Thus, the aim of this investigation was to characterize the neutrophilic inflammatory response after treatment of C3Heb/FeJ mice with 300 mg/kg acetaminophen. A time course study showed that neutrophils accumulate in the liver parallel to or slightly after the development of liver injury. The number of neutrophils in the liver was substantial (209 +/- 64 PMN/50 high-power fields at 12 h) compared to baseline levels (7 +/- 1). Serum levels of TNF-alpha and the C-X-C chemokines KC and MIP-2 increased by 28-, 14-, and 295-fold, respectively, over levels found in controls during the injury process. In addition, mRNA expression of MIP-2 and KC were upregulated in livers of acetaminophen-treated animals as determined by ribonuclease protection assay. However, none of these mediators were generated in large enough quantities to account for neutrophil sequestration in the liver. There was no upregulation of Mac-1 (CD11b/ CD18) or shedding of L-selectin on circulating neutrophils. Moreover, an anti-CD18 antibody had no protective effect against acetaminophen overdose during the first 24 h. These results indicate that there is a local inflammatory response after acetaminophen overdose, including a substantial accumulation of neutrophils in the liver. Because of the critical importance of beta2 integrins for neutrophil cytotoxicity, these results suggest that neutrophils do not contribute to the initiation or progression of AAP-induced liver. The inflammation observed after acetaminophen overdose may be characteristic for a response sufficient to recruit neutrophils for the purpose of removing necrotic cells but is not severe enough to cause additional damage. PMID:10774834

  1. Translational control of human neutrophil responses by MNK1.

    PubMed

    Fortin, Carl F; Mayer, Thomas Z; Cloutier, Alexandre; McDonald, Patrick P

    2013-10-01

    A growing number of inflammatory and immune processes in vivo have been shown to be influenced by neutrophil-derived cytokines. Whereas the underlying transcriptional mechanisms are increasingly well understood, the translational regulation of this neutrophil response remains largely unexplored. Here, we show that the MNK1, which participates in translational control in several cell types, is activated in response to physiological neutrophil agonists (LPS, TNF-α) in the cytoplasmic and nuclear compartments. With the use of various pharmacological inhibitors, we found that MNK1 activation takes place downstream of the TAK1-p38 MAPK axis in neutrophils, whereas the MEK/ERK, JNK, PI3K, and PKC pathways are not involved. Pharmacological blockade of MNK1, as well as overexpression experiments, established that cytokine protein synthesis (but not gene expression) is under the control of MNK1 in neutrophils. Likewise, MNK1 inhibition reversed the antiapoptotic effect of LPS and TNF-α in neutrophils, and this was accompanied by a decreased expression of the antiapoptotic protein Mcl-1. Thus, MNK1 appears to be an important regulator of neutrophil responses. Although MNK1 inhibition did not affect protein recruitment to mRNA caps, it decreased the phosphorylation of molecules implicated in translation initiation control, such as S6K, S6, and hyperphosphorylated 4E-BP1. These molecular targets of MNK1 are shared with those of PI3K in neutrophils, and accordingly, MNK1 inhibition partially impaired the belated PI3K/Akt activation elicited by LPS or TNF in these cells. Given the importance of neutrophils and their products in numerous chronic inflammatory disorders, MNK1 could represent an attractive therapeutic target. PMID:23401599

  2. Platelets enhance neutrophil transendothelial migration

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Platelets are increasingly recognized as important mediators of inflammation in addition to thrombosis. While platelets have been shown to promote neutrophil (PMN) adhesion to endothelium in various inflammatory models, it is unclear whether platelets enhance neutrophil transmigration across inflame...

  3. Kupffer cells and activation of endothelial TLR4 coordinate neutrophil adhesion within liver sinusoids during endotoxemia.

    PubMed

    McDonald, Braedon; Jenne, Craig N; Zhuo, Lisheng; Kimata, Koji; Kubes, Paul

    2013-12-01

    A key pathological feature of the systemic inflammatory response of sepsis/endotoxemia is the accumulation of neutrophils within the microvasculature of organs such as the liver, where they cause tissue damage and vascular dysfunction. There is emerging evidence that the vascular endothelium is critical to the orchestration of inflammatory responses to blood-borne microbes and microbial products in sepsis/endotoxemia. In this study, we aimed to understand the role of endothelium, and specifically endothelial TLR4 activation, in the regulation of neutrophil recruitment to the liver during endotoxemia. Intravital microscopy of bone marrow chimeric mice revealed that TLR4 expression by non-bone marrow-derived cells was required for neutrophil recruitment to the liver during endotoxemia. Furthermore, LPS-induced neutrophil adhesion in liver sinusoids was equivalent between wild-type mice and transgenic mice that express TLR4 only on endothelium (tlr4(-/-)Tie2(tlr4)), revealing that activation of endothelial TLR4 alone was sufficient to initiate neutrophil adhesion. Neutrophil arrest within sinusoids of endotoxemic mice requires adhesive interactions between neutrophil CD44 and endothelial hyaluronan. Intravital immunofluorescence imaging demonstrated that stimulation of endothelial TLR4 alone was sufficient to induce the deposition of serum-derived hyaluronan-associated protein (SHAP) within sinusoids, which was required for CD44/hyaluronan-dependent neutrophil adhesion. In addition to endothelial TLR4 activation, Kupffer cells contribute to neutrophil recruitment via a distinct CD44/HA/SHAP-independent mechanism. This study sheds new light on the control of innate immune activation within the liver vasculature during endotoxemia, revealing a key role for endothelial cells as sentinels in the detection of intravascular infections and coordination of neutrophil recruitment to the liver. PMID:24113769

  4. The Essential Role of Neutrophils during Infection with the Intracellular Bacterial Pathogen Listeria monocytogenes.

    PubMed

    Witter, Alexandra R; Okunnu, Busola M; Berg, Rance E

    2016-09-01

    Neutrophils have historically been characterized as first responder cells vital to host survival because of their ability to contain and eliminate bacterial and fungal pathogens. However, recent studies have shown that neutrophils participate in both protective and detrimental responses to a diverse array of inflammatory and infectious diseases. Although the contribution of neutrophils to extracellular infections has been investigated for decades, their specific role during intracellular bacterial infections has only recently been appreciated. During infection with the Gram-positive intracellular pathogen Listeria monocytogenes, neutrophils are recruited from the bone marrow to sites of infection where they use novel bacterial-sensing pathways leading to phagocytosis and production of bactericidal factors. This review summarizes the requirement of neutrophils during L. monocytogenes infection by examining both neutrophil trafficking and function during primary and secondary infection. PMID:27543669

  5. Complement factor H modulates the activation of human neutrophil granulocytes and the generation of neutrophil extracellular traps.

    PubMed

    Schneider, Andrea E; Sándor, Noémi; Kárpáti, Éva; Józsi, Mihály

    2016-04-01

    Factor H (FH) is a major inhibitor of the alternative pathway of complement activation in plasma and on certain host surfaces. In addition to being a complement regulator, FH can bind to various cells via specific receptors, including binding to neutrophil granulocytes through complement receptor type 3 (CR3; CD11b/CD18), and modulate their function. The cellular roles of FH are, however, poorly understood. Because neutrophils are important innate immune cells in inflammatory processes and the host defense against pathogens, we aimed at studying the effects of FH on various neutrophil functions, including the generation of extracellular traps. FH co-localized with CD11b on the surface of neutrophils isolated from peripheral blood of healthy individuals, and cell-bound FH retained its cofactor activity and enhanced C3b degradation. Soluble FH supported neutrophil migration and immobilized FH induced cell spreading. In addition, immobilized but not soluble FH enhanced IL-8 release from neutrophils. FH alone did not trigger the cells to produce neutrophil extracellular traps (NETs), but NET formation induced by PMA and by fibronectin plus fungal β-glucan were inhibited by immobilized, but not by soluble, FH. Moreover, in parallel with NET formation, immobilized FH also inhibited the production of reactive oxygen species induced by PMA and by fibronectin plus β-glucan. Altogether, these data indicate that FH has multiple regulatory roles on neutrophil functions. While it can support the recruitment of neutrophils, FH may also exert anti-inflammatory effects and influence local inflammatory and antimicrobial reactions, and reduce tissue damage by modulating NET formation. PMID:26938503

  6. [Leukemic neutrophilic dermatosis].

    PubMed

    Török, L; Kirschner, A; Gurzó, M; Krenács, L

    1999-03-28

    A case of a 67 year-old female patient with acute myeloid leukemia is presented. As the first manifestation of the disease, the patient had symptoms of Sweet's syndrome, later signs of gangrenous pyoderma have developed. This transient form is termed as a "leukemic neutrophilic dermatosis". The authors focus on the important diagnostic and prognostic value of this entity. PMID:10349319

  7. Neutrophils in cancer development and progression: Roles, mechanisms, and implications (Review).

    PubMed

    Zhang, Xu; Zhang, Wen; Yuan, Xiao; Fu, Min; Qian, Hui; Xu, Wenrong

    2016-09-01

    Neutrophils are predominant immune cells that protect the host from microbial infection. The roles of neutrophils in tumor have long been ignored due to their short life span and terminal differentiation phenotype. In recent years, emerging evidence indicates that neutrophils have phenotypic and functional plasticity. Neutrophils eliminate malignant cells by releasing the antimicrobial and cytotoxic contents in their granules or secreting immune mediators to recruit and activate other antitumor effector cells. On the contrary, tumor derived factors can convert neutrophils into a pro-tumor phenotype. Neutrophils have been shown to facilitate tumorigenesis, promote tumor growth and metastasis, stimulate tumor angiogenesis, and mediate immunosuppression. The number of neutrophils in blood and tumor tissues of cancer patients is associated with disease progression and patient outcome. In this review, we summarize the recent progress of neutrophils in the pathogenesis of cancer with an emphasis on neutrophil polarization. Better understanding of the mechanisms that regulate the dichotomy of neutrophils will not only shed light on their roles in cancer but also provide new approaches for cancer diagnosis and treatment. PMID:27573431

  8. Proteinase 3 and neutrophil elastase enhance inflammation in mice by inactivating antiinflammatory progranulin

    PubMed Central

    Kessenbrock, Kai; Fröhlich, Leopold; Sixt, Michael; Lämmermann, Tim; Pfister, Heiko; Bateman, Andrew; Belaaouaj, Azzaq; Ring, Johannes; Ollert, Markus; Fässler, Reinhard; Jenne, Dieter E.

    2008-01-01

    Neutrophil granulocytes form the body’s first line of antibacterial defense, but they also contribute to tissue injury and noninfectious, chronic inflammation. Proteinase 3 (PR3) and neutrophil elastase (NE) are 2 abundant neutrophil serine proteases implicated in antimicrobial defense with overlapping and potentially redundant substrate specificity. Here, we unraveled a cooperative role for PR3 and NE in neutrophil activation and noninfectious inflammation in vivo, which we believe to be novel. Mice lacking both PR3 and NE demonstrated strongly diminished immune complex–mediated (IC-mediated) neutrophil infiltration in vivo as well as reduced activation of isolated neutrophils by ICs in vitro. In contrast, in mice lacking just NE, neutrophil recruitment to ICs was only marginally impaired. The defects in mice lacking both PR3 and NE were directly linked to the accumulation of antiinflammatory progranulin (PGRN). Both PR3 and NE cleaved PGRN in vitro and during neutrophil activation and inflammation in vivo. Local administration of recombinant PGRN potently inhibited neutrophilic inflammation in vivo, demonstrating that PGRN represents a crucial inflammation-suppressing mediator. We conclude that PR3 and NE enhance neutrophil-dependent inflammation by eliminating the local antiinflammatory activity of PGRN. Our results support the use of serine protease inhibitors as antiinflammatory agents. PMID:18568075

  9. Leishmania amazonensis promastigotes induce and are killed by neutrophil extracellular traps

    PubMed Central

    Guimarães-Costa, Anderson B.; Nascimento, Michelle T. C.; Froment, Giselle S.; Soares, Rodrigo P. P.; Morgado, Fernanda N.; Conceição-Silva, Fátima; Saraiva, Elvira M.

    2009-01-01

    Neutrophils are short-lived leukocytes that die by apoptosis, necrosis, and NETosis. Upon death by NETosis, neutrophils release fibrous traps of DNA, histones, and granule proteins named neutrophil extracellular traps (NETs), which can kill bacteria and fungi. Inoculation of the protozoan Leishmania into the mammalian skin causes local inflammation with neutrophil recruitment. Here, we investigated the release of NETs by human neutrophils upon their interaction with Leishmania parasites and NETs' ability to kill this protozoan. The NET constituents DNA, elastase, and histones were detected in traps associated to promastigotes by immunofluorescence. Electron microscopy revealed that Leishmania was ensnared by NETs released by neutrophils. Moreover, Leishmania and its surface lipophosphoglycan induced NET release by neutrophils in a parasite number- and dose-dependent manner. Disruption of NETs by DNase treatment during Leishmania–neutrophil interaction increased parasite survival, evidencing NETs' leishmanicidal effect. Leishmania killing was also elicited by NET-rich supernatants from phorbol 12-myristate 13-acetate-activated neutrophils. Immunoneutralization of histone during Leishmania–neutrophil interaction partially reverted Leishmania killing, and purified histone killed the parasites. Meshes composed of DNA and elastase were evidenced in biopsies of human cutaneous leishmaniasis. NET is an innate response that might contribute to diminish parasite burden in the Leishmania inoculation site. PMID:19346483

  10. Granule Protein Processing and Regulated Secretion in Neutrophils

    PubMed Central

    Sheshachalam, Avinash; Srivastava, Nutan; Mitchell, Troy; Lacy, Paige; Eitzen, Gary

    2014-01-01

    Neutrophils are part of a family of granulocytes that, together with eosinophils and basophils, play an essential role in innate immunity. Neutrophils are the most abundant circulating leukocytes and are vital for rapid immune responses, being recruited to sites of injury or infection within minutes, where they can act as specialized phagocytic cells. However, another prominent function of neutrophils is the release of pro-inflammatory compounds, including cytokines, chemokines, and digestive enzymes, which are stored in intracellular compartments and released through regulated exocytosis. Hence, an important feature that contributes to rapid immune responses is capacity of neutrophils to synthesize and store pre-formed pro-inflammatory mediators in specialized intracellular vesicles and thus no new synthesis is required. This review will focus on advancement in three topics relevant to neutrophil secretion. First, we will examine what is known about basal level pro-inflammatory mediator synthesis, trafficking, and storage in secretory compartments. Second, we will review recent advancements in the mechanisms that control vesicle mobilization and the release of pre-formed mediators. Third, we will examine the upregulation and de novo synthesis of pro-inflammatory mediators by neutrophils engaged at sites of infection. PMID:25285096

  11. Permissive and protective roles for neutrophils in leishmaniasis.

    PubMed

    Carlsen, E D; Liang, Y; Shelite, T R; Walker, D H; Melby, P C; Soong, L

    2015-11-01

    Leishmania parasites are the causative agents of leishmaniasis, a neglected tropical disease that causes substantial morbidity and considerable mortality in many developing areas of the world. Recent estimates suggest that roughly 10 million people suffer from cutaneous leishmaniasis (CL), and approximately 76,000 are afflicted with visceral leishmaniasis (VL), which is universally fatal without treatment. Efforts to develop therapeutics and vaccines have been greatly hampered by an incomplete understanding of the parasite's biology and a lack of clear protective correlates that must be met in order to achieve immunity. Although parasites grow and divide preferentially in macrophages, a number of other cell types interact with and internalize Leishmania parasites, including monocytes, dendritic cells and neutrophils. Neutrophils appear to be especially important shortly after parasites are introduced into the skin, and may serve a dual protective and permissive role during the establishment of infection. Curiously, neutrophil recruitment to the site of infection appears to continue into the chronic phase of disease, which may persist for many years. The immunological impact of these cells during chronic leishmaniasis is unclear at this time. In this review we discuss the ways in which neutrophils have been observed to prevent and promote the establishment of infection, examine the role of anti-neutrophil antibodies in mouse models of leishmaniasis and consider recent findings that neutrophils may play a previously unrecognized role in influencing chronic parasite persistence. PMID:26126690

  12. Fructose-1,6-biphosphate and nucleoside pool modifications prevent neutrophil accumulation in the reperfused intestine.

    PubMed

    Sola, Anna; Panés, Julián; Xaus, Carme; Hotter, Georgina

    2003-01-01

    Fructose-1,6-biphosphate (F16BP) attenuates ischemia/reperfusion (I/R) injury by inhibiting microvascular leukocyte adhesion or reducing neutrophil-derived oxygen free-radical production, but the causes of this action, the mechanisms in vivo, and the possible implication of nucleoside pool modifications are still controversial issues. We explored whether F16BP's inhibition of free-radical production and neutrophil recruitment is a result of its effect on adenosine (Ado) accumulation during intestinal I/R injury. The effects of F16BP administration were tested on the nucleotide/nucleoside metabolism at the end of the ischemic period and on microvascular neutrophil recruitment and free-radical production after reperfusion in vivo, in the presence or absence of Ado deaminase (ADA). Infusion of F16BP markedly increased endogenous Ado, decreased xanthine accumulation during the ischemic period, and inhibited neutrophil recruitment and subsequent neutrophil free-radical generation during reperfusion. Administration of ADA reversed these processes. The results provide strong evidence that F16BP prevents neutrophil accumulation and neutrophil free-radical generation during intestinal I/R by a key mechanism that modifies the nucleoside pool, leading to an endogenous accumulation of Ado and to a reduction of xanthine during ischemia. PMID:12525564

  13. Aquaporin-9-expressing neutrophils are required for the establishment of contact hypersensitivity.

    PubMed

    Moniaga, Catharina Sagita; Watanabe, Sachiko; Honda, Tetsuya; Nielsen, Søren; Hara-Chikuma, Mariko

    2015-01-01

    Aquaporin-9 (AQP9), a water/glycerol channel protein, is expressed in several immune cells including neutrophils; however, its role in immune response remains unknown. Here we show the involvement of AQP9 in hapten-induced contact hypersensitivity (CHS), as a murine model of skin allergic contact dermatitis, using AQP9 knockout (AQP9(-/-)) mice. First, the CHS response to hapten dinitrofluorobenzene (DNFB) was impaired in AQP9(-/-) mice compared with wild-type (WT) mice. Adoptive transfer of sensitized AQP9(-/-) draining lymph node (dLN) cells into WT recipients resulted in a reduced CHS response, indicating impaired sensitization in AQP9(-/-) mice. Second, administration of WT neutrophils into AQP9(-/-) mice during sensitization rescued the impaired CHS response. Neutrophil recruitment to dLNs upon hapten application was attenuated by AQP9 deficiency. Coincidentally, AQP9(-/-) neutrophils showed a reduced CC-chemokine receptor 7 (CCR7) ligand-induced migration efficacy, which was attributed to the attenuated recruitment of neutrophils to dLNs. Furthermore, we found that neutrophil deficiency, observed in AQP9(-/-) or neutrophil-depleted mice, decreased IL-17A production by dLN cells, which might be responsible for T cell activation during a subsequent CHS response. Taken together, these findings suggest that AQP9 is required for the development of sensitization during cutaneous acquired immune responses via regulating neutrophil function. PMID:26489517

  14. Aquaporin-9-expressing neutrophils are required for the establishment of contact hypersensitivity

    PubMed Central

    Moniaga, Catharina Sagita; Watanabe, Sachiko; Honda, Tetsuya; Nielsen, Søren; Hara-Chikuma, Mariko

    2015-01-01

    Aquaporin-9 (AQP9), a water/glycerol channel protein, is expressed in several immune cells including neutrophils; however, its role in immune response remains unknown. Here we show the involvement of AQP9 in hapten-induced contact hypersensitivity (CHS), as a murine model of skin allergic contact dermatitis, using AQP9 knockout (AQP9−/−) mice. First, the CHS response to hapten dinitrofluorobenzene (DNFB) was impaired in AQP9−/− mice compared with wild-type (WT) mice. Adoptive transfer of sensitized AQP9−/− draining lymph node (dLN) cells into WT recipients resulted in a reduced CHS response, indicating impaired sensitization in AQP9−/− mice. Second, administration of WT neutrophils into AQP9−/− mice during sensitization rescued the impaired CHS response. Neutrophil recruitment to dLNs upon hapten application was attenuated by AQP9 deficiency. Coincidentally, AQP9−/− neutrophils showed a reduced CC-chemokine receptor 7 (CCR7) ligand-induced migration efficacy, which was attributed to the attenuated recruitment of neutrophils to dLNs. Furthermore, we found that neutrophil deficiency, observed in AQP9−/− or neutrophil-depleted mice, decreased IL-17A production by dLN cells, which might be responsible for T cell activation during a subsequent CHS response. Taken together, these findings suggest that AQP9 is required for the development of sensitization during cutaneous acquired immune responses via regulating neutrophil function. PMID:26489517

  15. Characterization of Neutrophil Function in Human Cutaneous Leishmaniasis Caused by Leishmania braziliensis

    PubMed Central

    Conceição, Jacilara; Davis, Richard; Carneiro, Pedro Paulo; Giudice, Angela; Muniz, Aline C.; Wilson, Mary E.; Carvalho, Edgar M.; Bacellar, Olívia

    2016-01-01

    Infection with different Leishmania spp. protozoa can lead to a variety of clinical syndromes associated in many cases with inflammatory responses in the skin. Although macrophages harbor the majority of parasites throughout chronic infection, neutrophils are the first inflammatory cells to migrate to the site of infection. Whether neutrophils promote parasite clearance or exacerbate disease in murine models varies depending on the susceptible or resistant status of the host. Based on the hypothesis that neutrophils contribute to a systemic inflammatory state in humans with symptomatic L. braziliensis infection, we evaluated the phenotype of neutrophils from patients with cutaneous leishmaniasis (CL) during the course of L. braziliensis infection. After in vitro infection with L. braziliensis, CL patient neutrophils produced more reactive oxygen species (ROS) and higher levels of CXCL8 and CXCL9, chemokines associated with recruitment of neutrophils and Th1-type cells, than neutrophils from control healthy subjects (HS). Despite this, CL patient and HS neutrophils were equally capable of phagocytosis of L. braziliensis. There was no difference between the degree of activation of neutrophils from CL versus healthy subjects, assessed by CD66b and CD62L expression using flow cytometry. Of interest, these studies revealed that both parasite-infected and bystander neutrophils became activated during incubation with L. braziliensis. The enhanced ROS and chemokine production in neutrophils from CL patients reverted to baseline after treatment of disease. These data suggest that the circulating neutrophils during CL are not necessarily more microbicidal, but they have a more pro-inflammatory profile after parasite restimulation than neutrophils from healthy subjects. PMID:27167379

  16. Characterization of Neutrophil Function in Human Cutaneous Leishmaniasis Caused by Leishmania braziliensis.

    PubMed

    Conceição, Jacilara; Davis, Richard; Carneiro, Pedro Paulo; Giudice, Angela; Muniz, Aline C; Wilson, Mary E; Carvalho, Edgar M; Bacellar, Olívia

    2016-05-01

    Infection with different Leishmania spp. protozoa can lead to a variety of clinical syndromes associated in many cases with inflammatory responses in the skin. Although macrophages harbor the majority of parasites throughout chronic infection, neutrophils are the first inflammatory cells to migrate to the site of infection. Whether neutrophils promote parasite clearance or exacerbate disease in murine models varies depending on the susceptible or resistant status of the host. Based on the hypothesis that neutrophils contribute to a systemic inflammatory state in humans with symptomatic L. braziliensis infection, we evaluated the phenotype of neutrophils from patients with cutaneous leishmaniasis (CL) during the course of L. braziliensis infection. After in vitro infection with L. braziliensis, CL patient neutrophils produced more reactive oxygen species (ROS) and higher levels of CXCL8 and CXCL9, chemokines associated with recruitment of neutrophils and Th1-type cells, than neutrophils from control healthy subjects (HS). Despite this, CL patient and HS neutrophils were equally capable of phagocytosis of L. braziliensis. There was no difference between the degree of activation of neutrophils from CL versus healthy subjects, assessed by CD66b and CD62L expression using flow cytometry. Of interest, these studies revealed that both parasite-infected and bystander neutrophils became activated during incubation with L. braziliensis. The enhanced ROS and chemokine production in neutrophils from CL patients reverted to baseline after treatment of disease. These data suggest that the circulating neutrophils during CL are not necessarily more microbicidal, but they have a more pro-inflammatory profile after parasite restimulation than neutrophils from healthy subjects. PMID:27167379

  17. Characterization of neutrophil function in Papillon-Lefèvre syndrome.

    PubMed

    Roberts, Helen; White, Phillipa; Dias, Irundika; McKaig, Sarah; Veeramachaneni, Ratna; Thakker, Nalin; Grant, Melissa; Chapple, Iain

    2016-08-01

    Papillon-Lefévre syndrome is a rare, inherited, autosomal-recessive disease, characterized by palmoplantar keratosis and severe prepubertal periodontitis, leading to premature loss of all teeth. Papillon-Lefévre syndrome is caused by a mutation in the cathepsin C gene, resulting in complete loss of activity and subsequent failure to activate immune response proteins. Periodontitis in Papillon-Lefévre syndrome is thought to arise from failure to eliminate periodontal pathogens as a result of cathepsin C deficiency, although mechanistic pathways remain to be elucidated. The aim of this study was to characterize comprehensively neutrophil function in Papillon-Lefévre syndrome. Peripheral blood neutrophils were isolated from 5 patients with Papillon-Lefévre syndrome, alongside matched healthy control subjects. For directional chemotactic accuracy, neutrophils were exposed to the chemoattractants MIP-1α and fMLP and tracked by real-time videomicroscopy. Reactive oxygen species generation was measured by chemiluminescence. Neutrophil extracellular trap formation was assayed fluorometrically, and proinflammatory cytokine release was measured following overnight culture of neutrophils with relevant stimuli. Neutrophil serine protease deficiencies resulted in a reduced ability of neutrophils to chemotax efficiently and an inability to generate neutrophil extracellular traps. Neutrophil extracellular trap-bound proteins were also absent in Papillon-Lefévre syndrome, and Papillon-Lefévre syndrome neutrophils released higher levels of proinflammatory cytokines in unstimulated and stimulated conditions, and plasma cytokines were elevated. Notably, neutrophil chemoattractants MIP-1α and CXCL8 were elevated in Papillon-Lefévre syndrome neutrophils, as was reactive oxygen species formation. We propose that relentless recruitment and accumulation of hyperactive/reactive neutrophils (cytokines, reactive oxygen species) with increased tissue transit times into periodontal

  18. Nanoparticle Targeting of Neutrophils for Improved Cancer Immunotherapy

    PubMed Central

    Chu, Dafeng; Zhao, Qi; Yu, Jian; Zhang, Faya; Zhang, Hui; Wang, Zhenjia

    2016-01-01

    Cancer immunotherapy using tumor specific monoclonal antibodies (mAbs) presents a novel approach for cancer treatment. A monoclonal antibody TA99 specific for gp75 antigen of melanoma, initiates neutrophil recruitment in tumor responsible for cancer therapy. Here we report a strategy for hijacking neutrophils in vivo using nanoparticles (NPs) to deliver therapeutics into tumor. In a mouse model of melanoma, we showed that systemically delivered albumin NPs increased in tumor when TA99 antibody was injected; and the nanoparticle tumor accumulation was mediated by neutrophils. After the administration of pyropheophorbide-a (Ppa) loaded albumin NPs and TA99, photodynamic therapy significantly suppressed the tumor growth and increased mouse survival compared with treatment with the NPs or TA99. The study reveals a new avenue to treat cancer by nanoparticle hitchhiking of immune systems to enhance delivery of therapeutics into tumor sites. PMID:26989887

  19. Monocytic cell differentiation from band-stage neutrophils under inflammatory conditions via MKK6 activation

    PubMed Central

    Köffel, René; Meshcheryakova, Anastasia; Warszawska, Joanna; Hennig, Annika; Wagner, Karin; Jörgl, Almut; Gubi, Daniela; Moser, Doris; Hladik, Anastasiya; Hoffmann, Ulrike; Fischer, Michael B.; van den Berg, Wim; Koenders, Marije; Scheinecker, Clemens; Gesslbauer, Bernhard; Knapp, Sylvia

    2014-01-01

    During inflammation, neutrophils are rapidly mobilized from the bone marrow storage pool into peripheral blood (PB) to enter lesional sites, where most rapidly undergo apoptosis. Monocytes constitute a second wave of inflammatory immigrates, giving rise to long-lived macrophages and dendritic cell subsets. According to descriptive immunophenotypic and cell culture studies, neutrophils may directly “transdifferentiate” into monocytes/macrophages. We provide mechanistic data in human and murine models supporting the existence of this cellular pathway. First, the inflammatory signal–induced MKK6-p38MAPK cascade activates a monocyte differentiation program in human granulocyte colony-stimulating factor–dependent neutrophils. Second, adoptively transferred neutrophils isolated from G-CSF–pretreated mice rapidly acquired monocyte characteristics in response to inflammatory signals in vivo. Consistently, inflammatory signals led to the recruitment of osteoclast progenitor cell potential from ex vivo–isolated G-CSF–mobilized human blood neutrophils. Monocytic cell differentiation potential was retained in left-shifted band-stage neutrophils but lost in neutrophils from steady-state PB. MKK6-p38MAPK signaling in HL60 model cells led to diminishment of the transcription factor C/EBPα, which enabled the induction of a monocytic cell differentiation program. Gene profiling confirmed lineage conversion from band-stage neutrophils to monocytic cells. Therefore, inflammatory signals relayed by the MKK6-p38MAPK cascade induce monocytic cell differentiation from band-stage neutrophils. PMID:25214442

  20. The crucial role of neutrophil granulocytes in bone fracture healing.

    PubMed

    Kovtun, A; Bergdolt, S; Wiegner, R; Radermacher, P; Huber-Lang, M; Ignatius, A

    2016-01-01

    Delayed bone fracture healing and the formation of non-unions represent an important clinical problem, particularly in polytrauma patients who suffer from posttraumatic systemic inflammation. However, the underlying pathomechanisms remain unclear. Neutrophil granulocytes are crucial effector cells in the systemic immune response and represent the most abundant immune cell population in the early fracture haematoma. Here we investigated the role of neutrophils in a mouse model of uncomplicated fracture healing and compromised fracture healing induced by an additional thoracic trauma. Twenty four hours before injury, 50 % of the mice were systemically treated with an anti-Ly-6G-antibody to reduce neutrophil numbers. In the isolated fracture model, Ly-6G-Ab treatment significantly increased the concentration of both pro- and anti-inflammatory cytokines, including interleukin (IL)-6 and IL-10, and chemokines, for example, C-X-C motif ligand 1 (CXCL1) and monocyte chemotactic protein-1 (MCP-1), in the fracture haematoma. Monocyte/macrophage recruitment was also significantly enhanced. After 21 d, bone regeneration was considerably impaired as demonstrated by significantly diminished bone content and impaired mechanical properties of the fracture callus. These results indicate that undisturbed neutrophil recruitment and function in the inflammatory phase after fracture is crucial to initiate downstream responses leading to bone regeneration. In the combined trauma model, the reduction of neutrophil numbers ameliorated pulmonary inflammation but did not provoke any significant effect on bone regeneration, suggesting that neutrophils may not play a crucial pathomechanistic role in compromised fracture healing induced by an additional thoracic trauma. PMID:27452963

  1. Apoptotic cell clearance of Leishmania major-infected neutrophils by dendritic cells inhibits CD8+ T-cell priming in vitro by Mer tyrosine kinase-dependent signaling

    PubMed Central

    Ribeiro-Gomes, F L; Romano, A; Lee, S; Roffê, E; Peters, N C; Debrabant, A; Sacks, D

    2015-01-01

    Neutrophils are the predominant recruited and infected cells during the early stages of Leishmania major infection in the skin, and depletion of neutrophils promotes immunity to infection transmitted by sand fly bite. In order to better understand how the acute neutrophilic response suppresses immunity, we assessed the consequences of the interaction between neutrophils recovered from the skin-inoculation site and bone marrow-derived dendritic cells (DCs) in vitro. The capture of infected, apoptotic neutrophils by the DCs completely inhibited their cross-presentation function that was dependent on engagement of the receptor tyrosine kinase Mer on the DCs. The capture of uninfected neutrophils, or neutrophils infected with Toxoplasma gondii, had only slight immunomodulatory effects. These studies define the clearance of infected, apoptotic neutrophils by DCs and Mer receptor signaling as central to the early immune evasion strategies of L. major, with relevance to other vector-borne pathogens delivered by bite to the skin. PMID:26658192

  2. Neutrophil-mediated protection of cultured human vascular endothelial cells from damage by growing Candida albicans hyphae

    SciTech Connect

    Edwards, J.E. Jr.; Rotrosen, D.; Fontaine, J.W.; Haudenschild, C.C.; Diamond, R.D.

    1987-05-01

    Interactions were studied between human neutrophils and cultured human umbilical vein endothelial cells invaded by Candida albicans. In the absence of neutrophils, progressive Candida germination and hyphal growth extensively damaged endothelial cell monolayers over a period of 4 to 6 hours, as determined both by morphological changes and release of /sup 51/Cr from radiolabeled endothelial cells. Monolayers were completely destroyed and replaced by hyphae after 18 hours of incubation. In contrast, when added 2 hours after the monolayers had been infected with Candida, neutrophils selectively migrated toward and attached to hyphae at points of hyphal penetration into individual endothelial cells (observed by time-lapse video-microscopy). Attached neutrophils spread over hyphal surfaces both within and beneath the endothelial cells; neutrophil recruitment to initial sites of leukocyte-Candida-endothelial cell interactions continued throughout the first 60 minutes of observation. Neutrophil spreading and stasis were observed only along Candida hyphae and at sites of Candida-endothelial cell interactions. These events resulted in 58.0% killing of Candida at 2 hours and subsequent clearance of Candida from endothelial cell monolayers, as determined by microcolony counts and morphological observation. On introduction of additional neutrophils to yield higher ratios of neutrophils to endothelial cells (10 neutrophils:1 endothelial cell), neutrophil migration toward hyphal elements continued. Despite retraction or displacement of occasional endothelial cells by invading Candida and neutrophils, most endothelial cells remained intact, viable, and motile as verified both by morphological observations and measurement of /sup 51/Cr release from radiolabeled monolayers.

  3. Oral Neutrophil Transcriptome Changes Result in a Pro-Survival Phenotype in Periodontal Diseases

    PubMed Central

    Lakschevitz, Flavia S.; Aboodi, Guy M.; Glogauer, Michael

    2013-01-01

    Background Periodontal diseases are inflammatory processes that occur following the influx of neutrophils into the periodontal tissues in response to the subgingival bacterial biofilm. Current literature suggests that while neutrophils are protective and prevent bacterial infections, they also appear to contribute to damage of the periodontal tissues. In the present study we compare the gene expression profile changes in neutrophils as they migrate from the circulation into the oral tissues in patients with chronic periodontits and matched healthy subjects. We hypothesized that oral neutrophils in periodontal disease patients will display a disease specific transcriptome that differs from the oral neutrophil of healthy subjects. Methods Venous blood and oral rinse samples were obtained from healthy subjects and chronic periodontitis patients for neutrophil isolation. mRNA was isolated from the neutrophils, and gene expression microarray analysis was completed. Results were confirmed for specific genes of interest by qRT-PCR and Western Blot analysis. Results and Discussion Chronic periodontitis patients presented with increased recruitment of neutrophils to the oral cavity. Gene expression analysis revealed differences in the expression levels of genes from several biological pathways. Using hierarchical clustering analysis, we found that the apoptosis network was significantly altered in patients with chronic inflammation in the oral cavity, with up-regulation of pro-survival members of the Bcl-2 family and down-regulation of pro-apoptosis members in the same compartment. Additional functional analysis confirmed that the percentages of viable neutrophils are significantly increased in the oral cavity of chronic periodontitis patients. Conclusions Oral neutrophils from patients with periodontal disease displayed an altered transcriptome following migration into the oral tissues. This resulted in a pro-survival neutrophil phenotype in chronic periodontitis patients

  4. Reactive oxygen species (ROS)-induced actin glutathionylation controls actin dynamics in neutrophils

    PubMed Central

    Sakai, Jiro; Li, Jingyu; Subramanian, Kulandayan K.; Mondal, Subhanjan; Bajrami, Besnik; Hattori, Hidenori; Jia, Yonghui; Dickinson, Bryan C.; Zhong, Jia; Ye, Keqiang; Chang, Christopher J; Ho, Ye-Shih; Zhou, Jun; Luo, Hongbo R.

    2012-01-01

    Summary The regulation of actin dynamics is pivotal for cellular processes such as cell adhesion, migration, and phagocytosis, and thus is crucial for neutrophils to fulfill their roles in innate immunity. Many factors have been implicated in signal-induced actin polymerization, however the essential nature of the potential negative modulators are still poorly understood. Here we report that NADPH oxidase-dependent physiologically generated reactive oxygen species (ROS) negatively regulate actin polymerization in stimulated neutrophils via driving reversible actin glutathionylation. Disruption of glutaredoxin 1 (Grx1), an enzyme that catalyzes actin deglutathionylation, increased actin glutathionylation, attenuated actin polymerization, and consequently impaired neutrophil polarization, chemotaxis, adhesion, and phagocytosis. Consistently, Grx1-deficient murine neutrophils showed impaired in vivo recruitment to sites of inflammation and reduced bactericidal capability. Together, these results present a physiological role for glutaredoxin and ROS- induced reversible actin glutathionylation in regulation of actin dynamics in neutrophils. PMID:23159440

  5. Neutrophil swarms require LTB4 and integrins at sites of cell death in vivo

    PubMed Central

    Lämmermann, Tim; Afonso, Philippe V.; Angermann, Bastian R.; Wang, Ji Ming; Kastenmüller, Wolfgang; Parent, Carole A.; Germain, Ronald N.

    2013-01-01

    Neutrophil recruitment from blood to extravascular sites of sterile or infectious tissue damage is a hallmark of early innate immune responses, and the molecular events leading to cell exit from the bloodstream have been well defined1,2. Once outside the vessel, individual neutrophils often show extremely coordinated chemotaxis and cluster formation reminiscent of the swarming behaviour of insects3–11. The molecular players that direct this response at the single-cell and population levels within the complexity of an inflamed tissue are unknown. Using two-photon intravital microscopy in mouse models of sterile injury and infection, we show a critical role for intercellular signal relay among neutrophils mediated by the lipid leukotriene B4, which acutely amplifies local cell death signals to enhance the radius of highly directed interstitial neutrophil recruitment. Integrin receptors are dispensable for long-distance migration12, but have a previously unappreciated role in maintaining dense cellular clusters when congregating neutrophils rearrange the collagenous fibre network of the dermis to form a collagen-free zone at the wound centre. In this newly formed environment, integrins, in concert with neutrophil-derived leukotriene B4 and other chemoattractants, promote local neutrophil interaction while forming a tight wound seal. This wound seal has borders that cease to grow in kinetic concert with late recruitment of monocytes and macrophages at the edge of the displaced collagen fibres. Together, these data provide an initial molecular map of the factors that contribute to neutrophil swarming in the extravascular space of a damaged tissue. They reveal how local events are propagated over large-range distances, and how auto-signalling produces coordinated, self-organized neutrophil-swarming behaviour that isolates the wound or infectious site from surrounding viable tissue. PMID:23708969

  6. Marine Natural Product Inhibitors of Neutrophil-Associated Inflammation.

    PubMed

    Chen, Chun-Yu; Tsai, Yung-Fong; Chang, Wen-Yi; Yang, Shun-Chin; Hwang, Tsong-Long

    2016-01-01

    Neutrophils are widely recognized to play an important role in acute inflammatory responses, and recent evidence has expanded their role to modulating chronic inflammatory and autoimmune diseases. Reactive oxygen species (ROS) and microbicidal compounds released from neutrophils that are recruited to the site of inflammation contribute to the pathogenesis of multiple inflammation-associated diseases such as chronic obstructive pulmonary disease, atherosclerosis, and hepatitis. Marine organisms are a valuable source of bioactive compounds with potential for industrial and pharmaceutical application. Marine natural products that inhibit neutrophil activation could be used as drugs for the treatment of inflammatory diseases. Numerous studies investigating marine natural products have reported novel anti-inflammatory agents. Nevertheless, the detailed mechanisms underlying their actions, which could facilitate our understanding of the molecular events occurring in neutrophils, have not been reported in most of the associated research studies. Therefore, in this review, we will present marine products that inhibit neutrophil-associated inflammation. Furthermore, we will be limiting the detailed discussion to agents with well-investigated molecular targets. PMID:27472345

  7. Neutrophil-Epithelial Interactions: A Double-Edged Sword.

    PubMed

    Parkos, Charles A

    2016-06-01

    In recent years, it has become clear that innate immune cells termed neutrophils act as double-edged swords by playing essential roles in clearing infection but also causing tissue damage, yet being critical for wound healing. Neutrophil recruitment to sites of injured tissue or infection has been well studied, and many of the molecular events that regulate passage of leukocytes out of the microcirculation are now understood. However, after exiting the circulation, the molecular details that regulate neutrophil passage to end targets, such mucosal surfaces, are just beginning to be appreciated. Given that migration of neutrophils across mucosal epithelia is associated with disease symptoms and disruption of critical barrier function in disorders such as inflammatory bowel disease, there has been long-standing interest in understanding the molecular basis and functional consequences of neutrophil-epithelial interactions. It is a great honor that my work was recognized by the Rous-Whipple Award this past year, giving me the opportunity to summarize what we have learned during the past few decades about leukocyte interactions with epithelial cells. PMID:27083514

  8. Synthesis and biological evaluation of neutrophilic inflammation inhibitors.

    PubMed

    Bruno, Olga; Brullo, Chiara; Arduino, Nicoletta; Schenone, Silvia; Ranise, Angelo; Bondavalli, Francesco; Ottonello, Luciano; Dapino, Patrizia; Dallegri, Franco

    2004-03-01

    In several non-infectious human diseases, such as ulcerous colitis, rheumatoid arthritis, chronic obstructive pulmonary disease (COPD), the extravasal recruitment of neutrophils plays a crucial role in the development of tissue damage, which, when persistent, can lead to the irreversible organ dysfunction. The neutrophil activation is controlled by a number of intracellular pathways, particularly by a cAMP-dependent protein kinase A (PKA) which also acts on phosphodiesterase IV (PDE4) gene stimulating the synthesis of this enzyme, able to transform cAMP to inactive AMP. PDE4 inhibitors enhance intracellular cAMP and decrease inflammatory cell activation. Several 3-cyclopentyloxy-4-methoxybenzaldehyde and 3-cyclopentyloxy-4-methoxybenzoic acid derivatives were synthesized and studied by us to evaluate their ability to inhibit the superoxide anion production in human neutrophils. These compounds were found able to inhibit the neutrophil activation and some of them increased the cAMP level on tumor necrosis factor-alpha-stimulated neutrophils. Moreover, they also inhibited selectively the human PDE4 enzyme, although they are less potent than the reference compound Rolipram. We report here synthesis, biological studies and some SAR considerations concerning the above mentioned compounds. PMID:14987986

  9. Marine Natural Product Inhibitors of Neutrophil-Associated Inflammation

    PubMed Central

    Chen, Chun-Yu; Tsai, Yung-Fong; Chang, Wen-Yi; Yang, Shun-Chin; Hwang, Tsong-Long

    2016-01-01

    Neutrophils are widely recognized to play an important role in acute inflammatory responses, and recent evidence has expanded their role to modulating chronic inflammatory and autoimmune diseases. Reactive oxygen species (ROS) and microbicidal compounds released from neutrophils that are recruited to the site of inflammation contribute to the pathogenesis of multiple inflammation-associated diseases such as chronic obstructive pulmonary disease, atherosclerosis, and hepatitis. Marine organisms are a valuable source of bioactive compounds with potential for industrial and pharmaceutical application. Marine natural products that inhibit neutrophil activation could be used as drugs for the treatment of inflammatory diseases. Numerous studies investigating marine natural products have reported novel anti-inflammatory agents. Nevertheless, the detailed mechanisms underlying their actions, which could facilitate our understanding of the molecular events occurring in neutrophils, have not been reported in most of the associated research studies. Therefore, in this review, we will present marine products that inhibit neutrophil-associated inflammation. Furthermore, we will be limiting the detailed discussion to agents with well-investigated molecular targets. PMID:27472345

  10. Targeted deletion of tumor suppressor PTEN augments neutrophil function and enhances host defense in neutropenia-associated pneumonia

    PubMed Central

    Li, Yitang; Jia, Yonghui; Pichavant, Muriel; Loison, Fabien; Sarraj, Bara; Kasorn, Anongnard; You, Jian; Robson, Bryanne E.; Umetsu, Dale T.; Mizgerd, Joseph P.; Ye, Keqiang

    2009-01-01

    Neutropenia and related infections are the most important dose-limiting toxicities in anticancer chemotherapy and radiotherapy. In this study, we explored a new strategy for augmenting host defense in neutropenia-related pneumonia. Phosphatidylinositol-3,4,5-trisphosphate (PtdIns(3,4,5)P3) signaling in neutrophils was elevated by depleting PTEN, a phosphatidylinositol 3′-phosphatase that hydrolyzes PtdIns(3,4,5)P3. In myeloid-specific PTEN knockout mice, significantly more neutrophils were recruited to the inflamed lungs during neutropenia-associated pneumonia. Using an adoptive transfer technique, we demonstrated that this enhancement could be caused directly by PTEN depletion in neutrophils. In addition, disruption of PTEN increased the recruitment of macrophages and elevated proinflammatory cytokines/chemokine levels in the inflamed lungs, which could also be responsible for the enhanced neutrophil recruitment. Depleting PTEN also significantly delayed apoptosis and enhanced the bacteria-killing capability of the recruited neutrophils. Finally, we provide direct evidence that enhancement of neutrophil function by elevating PtdIns(3,4,5)P3 signaling can alleviate pneumonia-associated lung damage and decrease pneumonia-elicited mortality. Collectively, these results not only provide insight into the mechanism of action of PTEN and PtdIns(3,4,5)P3 signaling pathway in modulating neutrophil function during lung infection and inflammation, but they also establish PTEN and related pathways as potential therapeutic targets for treating neutropenia-associated pneumonia. PMID:19286998

  11. Whole blood human neutrophil trafficking in a microfluidic model of infection and inflammation.

    PubMed

    Hamza, Bashar; Irimia, Daniel

    2015-06-21

    Appropriate inflammatory responses to wounds and infections require adequate numbers of neutrophils arriving at injury sites. Both insufficient and excessive neutrophil recruitment can be detrimental, favouring systemic spread of microbes or triggering severe tissue damage. Despite its importance in health and disease, the trafficking of neutrophils through tissues remains difficult to control and the mechanisms regulating it are insufficiently understood. These mechanisms are also complex and difficult to isolate using traditional in vivo models. Here we designed a microfluidic model of tissue infection/inflammation, in which human neutrophils emerge from a droplet-size samples of whole blood and display bi-directional traffic between this and micro-chambers containing chemoattractant and microbe-like particles. Two geometrical barriers restrict the entrance of red blood cells from the blood to the micro-chambers and simulate the mechanical function of the endothelial barrier separating the cells in blood from cells in tissues. We found that in the presence of chemoattractant, the number of neutrophils departing the chambers by retrotaxis is in dynamic equilibrium with the neutrophils recruited by chemotaxis. We also found that in the presence of microbe-like particles, the number of neutrophils trapped in the chambers is proportional to the number of particles. Together, the dynamic equilibrium between migration, reversed-migration and trapping processes determine the optimal number of neutrophils at a site. These neutrophils are continuously refreshed and responsive to the number of microbes. Further studies using this infection-inflammation-on-a-chip-model could help study the processes of inflammation resolution. The new in vitro experimental tools may also eventually help testing new therapeutic strategies to limit neutrophil accumulation in tissues during chronic inflammation, without increasing the risk for infections. PMID:25987163

  12. IFN-γ induction by neutrophil-derived IL-17A homodimer augments pulmonary antibacterial defense.

    PubMed

    Cai, S; Batra, S; Langohr, I; Iwakura, Y; Jeyaseelan, S

    2016-05-01

    The role of interleukin-17A (IL-17A) in host defense against Legionella pneumophila remains elusive. To address this issue, we used Il17a(-/-), Il17f(-/-), and Il17a/Il17f(-/-) mice on a C57Bl/6 (non-permissive) background and IL-17 neutralizing Abs in mice on an A/J (permissive) background. Higher bacterial (L. pneumophila) counts in the lung and blood along with reduced neutrophil recruitment were detected in Il17a(-/-), but not Il17f(-/-), mice. We found that neutrophils produce IL-17A homodimer (IL-17A) during L. pneumophila infection, and hematopoietic cell-derived IL-17A is known to be important for bacterial clearance. Thus, intratracheal administration of wild-type neutrophils or recombinant IL-17A restored bacterial clearance and neutrophil recruitment in Il17a(-/-) mice. Furthermore, neutrophil-depleted Rag2(-/-) and Rag2/Il-2rγ(-/-) mice exhibited increased bacterial burden, reduced neutrophil influx and IL-17A production in the lung. Recombinant IFN-γ administration in Il17a(-/-) mice augmented bacterial elimination, whereas IL-17A administration in Ifnγ(-/-) mice did not augment bacterial clearance. IFN-γ is produced by T cells, but not neutrophils or macrophages, suggesting that neutrophil-derived IL-17A induces IFN-γ in a paracrine fashion. Human pneumonic lungs and human neutrophils challenged with L. pneumophila exhibited increased numbers of IL-17A producing cells. These findings display a novel function of neutrophil-derived IL-17A in antibacterial defense via the induction of IFN-γ in a paracrine manner. PMID:26349661

  13. The role of neutrophils in myocardial ischemia-reperfusion injury.

    PubMed

    Jordan, J E; Zhao, Z Q; Vinten-Johansen, J

    1999-09-01

    Reperfusion of ischemic myocardium is necessary to salvage tissue from eventual death. However, reperfusion after even brief periods of ischemia is associated with pathologic changes that represent either an acceleration of processes initiated during ischemia per se, or new pathophysiological changes that were initiated after reperfusion. This 'reperfusion injury' shares many characteristics with inflammatory responses in the myocardium. Neutrophils feature prominently in this inflammatory component of postischemic injury. Ischemia-reperfusion prompts a release of oxygen free radicals, cytokines and other proinflammatory mediators that activate both the neutrophils and the coronary vascular endothelium. Activation of these cell types promotes the expression of adhesion molecules on both the neutrophils and endothelium, which recruits neutrophils to the surface of the endothelium and initiate a specific cascade of cell-cell interactions, leading first to adherence of neutrophils to the vascular endothelium, followed later by transendothelial migration and direct interaction with myocytes. This specific series of events is a prerequisite to the phenotypic expression of reperfusion injury, including endothelial dysfunction, microvascular collapse and blood flow defects, myocardial infarction and apoptosis. Pharmacologic therapy can target the various components in this critical series of events. Effective targets for these pharmacologic agents include: (a) inhibiting the release or accumulation of proinflammatory mediators, (b) altering neutrophil or endothelial cell activation and (c) attenuating adhesion molecule expression on endothelium, neutrophils and myocytes. Monoclonal antibodies to adhesion molecules (P-selectin, L-selectin, CD11, CD18), complement fragments and receptors attenuate neutrophil-mediated injury (vascular injury, infarction), but clinical application may encounter limitations due to antigen-antibody reactions with the peptides. Humanized

  14. Serum and glucocorticoid-regulated kinase 1 regulates neutrophil clearance during inflammation resolution.

    PubMed

    Burgon, Joseph; Robertson, Anne L; Sadiku, Pranvera; Wang, Xingang; Hooper-Greenhill, Edward; Prince, Lynne R; Walker, Paul; Hoggett, Emily E; Ward, Jonathan R; Farrow, Stuart N; Zuercher, William J; Jeffrey, Philip; Savage, Caroline O; Ingham, Philip W; Hurlstone, Adam F; Whyte, Moira K B; Renshaw, Stephen A

    2014-02-15

    The inflammatory response is integral to maintaining health by functioning to resist microbial infection and repair tissue damage. Large numbers of neutrophils are recruited to inflammatory sites to neutralize invading bacteria through phagocytosis and the release of proteases and reactive oxygen species into the extracellular environment. Removal of the original inflammatory stimulus must be accompanied by resolution of the inflammatory response, including neutrophil clearance, to prevent inadvertent tissue damage. Neutrophil apoptosis and its temporary inhibition by survival signals provides a target for anti-inflammatory therapeutics, making it essential to better understand this process. GM-CSF, a neutrophil survival factor, causes a significant increase in mRNA levels for the known anti-apoptotic protein serum and glucocorticoid-regulated kinase 1 (SGK1). We have characterized the expression patterns and regulation of SGK family members in human neutrophils and shown that inhibition of SGK activity completely abrogates the antiapoptotic effect of GM-CSF. Using a transgenic zebrafish model, we have disrupted sgk1 gene function and shown this specifically delays inflammation resolution, without altering neutrophil recruitment to inflammatory sites in vivo. These data suggest SGK1 plays a key role in regulating neutrophil survival signaling and thus may prove a valuable therapeutic target for the treatment of inflammatory disease. PMID:24431232

  15. Serum and Glucocorticoid Regulated Kinase 1 (SGK1) Regulates Neutrophil Clearance During Inflammation Resolution

    PubMed Central

    Burgon, Joseph; Robertson, Anne L.; Sadiku, Pranvera; Wang, Xingang; Hooper-Greenhill, Edward; Prince, Lynne R.; Walker, Paul; Hoggett, Emily E.; Ward, Jonathan R.; Farrow, Stuart N.; Zuercher, William J.; Jeffrey, Philip; Savage, Caroline O.; Ingham, Philip W.; Hurlstone, Adam F.; Whyte, Moira K. B.; Renshaw, Stephen A.

    2013-01-01

    The inflammatory response is integral to maintaining health, by functioning to resist microbial infection and repair tissue damage. Large numbers of neutrophils are recruited to inflammatory sites to neutralise invading bacteria through phagocytosis and the release of proteases and reactive oxygen species into the extracellular environment. Removal of the original inflammatory stimulus must be accompanied by resolution of the inflammatory response, including neutrophil clearance, to prevent inadvertent tissue damage. Neutrophil apoptosis and its temporary inhibition by survival signals provides a target for anti-inflammatory therapeutics, making it essential to better understand this process. GM-CSF, a neutrophil survival factor, causes a significant increase in mRNA levels for the known anti-apoptotic protein Serum and Glucocorticoid Regulated Kinase 1 (SGK1). We have characterised the expression patterns and regulation of SGK family members in human neutrophils, and shown that inhibition of SGK activity completely abrogates the anti-apoptotic effect of GM-CSF. Using a transgenic zebrafish model, we have disrupted sgk1 gene function and shown this specifically delays inflammation resolution, without altering neutrophil recruitment to inflammatory sites in vivo. These data suggest SGK1 plays a key role in regulating neutrophil survival signalling, and thus may prove a valuable therapeutic target for the treatment of inflammatory disease. PMID:24431232

  16. Distinct Infiltration of Neutrophils in Lesion Shoulders in ApoE−/− Mice

    PubMed Central

    Rotzius, Pierre; Thams, Sebastian; Soehnlein, Oliver; Kenne, Ellinor; Tseng, Chi-Nan; Björkström, Niklas K.; Malmberg, Karl-Johan; Lindbom, Lennart; Eriksson, Einar E.

    2010-01-01

    Inflammation and activation of immune cells are key mechanisms in the development of atherosclerosis. Previous data indicate important roles for monocytes and T-lymphocytes in lesions. However, recent data suggest that neutrophils also may be of importance in atherogenesis. Here, we use apolipoprotein E (ApoE)-deficient mice with fluorescent neutrophils and monocytes (ApoE−/−/LysEGFP/EGFP mice) to specifically study neutrophil presence and recruitment in atherosclerotic lesions. We show by flow cytometry and confocal microscopy that neutrophils make up for 1.8% of CD45+ leukocytes in the aortic wall of ApoE−/−/LysEGFP/EGFP mice and that their contribution relative to monocyte/macrophages within lesions is approximately 1:3. However, neutrophils accumulate at sites of monocyte high density, preferentially in shoulder regions of lesions, and may even outnumber monocyte/macrophages in these areas. Furthermore, intravital microscopy established that a majority of leukocytes interacting with endothelium on lesion shoulders are neutrophils, suggesting a significant recruitment of these cells to plaque. These data demonstrate neutrophilic granulocytes as a major cellular component of atherosclerotic lesions in ApoE−/− mice and call for further study on the roles of these cells in atherogenesis. PMID:20472897

  17. The anti-inflammatory drug nimesulide rescues alpha-1-proteinase inhibitor from oxidative inactivation by phagocytosing neutrophils.

    PubMed

    Dallegri, F; Ottonello, L; Dapino, P; Bevilacqua, M

    1992-01-01

    When neutrophils are recruited to tissue sites and exposed to phagocytosable targets, they release oxidants which may be responsible for the local inactivation of alpha-1-proteinase inhibitor (A1PI). Consequently, A1PI becomes incapable of inhibiting the proteolytic activity of elastase, released at the same time by neutrophils as a result of leakage from phagocytic vacuoles. In the present paper we show that phagocytosing neutrophils inactivate A1PI via a process inhibitable by chemical agents known to interfere with the hypochlorous acid (HOCl)-generating myeloperoxidase pathway. The anti-inflammatory drug nimesulide (NMS), which is able to efficiently limit the extracellular availability of HOCl in the neutrophil surroundings, was found to prevent the inactivation of A1PI by neutrophils. The results provide evidence for a possible way to control neutrophil elastase activity by rescuing its natural inhibitor (A1PI) at inflamed tissue sites during infectious and noninfectious processes. PMID:1579712

  18. Neutrophil swarming toward Cryptococcus neoformans is mediated by complement and leukotriene B4.

    PubMed

    Sun, Donglei; Shi, Meiqing

    2016-09-01

    Swarming behavior of neutrophils has been noticed in both sterile injury and infection models and the mechanisms are being unveiled. So far, no in vitro model has been established to study neutrophil swarming to microbes. In the current study, using live-cell imaging, we observed in vitro neutrophil swarming toward Cryptococcus neoformans, a fungal pathogen causing human meningoencephalitis. Complement C3 and CD11b expression are essential for neutrophils to form cell swarms surrounding C. neoformans. Leukotriene B4 (LTB4) was quickly released by neutrophils during their interactions with C. neoformans. Blockade of LTB4 synthesis inhibited the swarming response to C. neoformans. Importantly, blockade of LTB4 synthesis also significantly reduced neutrophil recruitment in the lung vasculature of mice infected intravenously with C. neoformans, demonstrating a critical role of LTB4 in intravascular neutrophil swarming during infection. Together, this is the first report of neutrophil dynamics of swarming toward a microorganism in vitro, mediated by complement and LTB4. PMID:27402276

  19. A Simple and Efficient Method to Detect Nuclear Factor Activation in Human Neutrophils by Flow Cytometry

    PubMed Central

    García-García, Erick; Uribe-Querol, Eileen; Rosales, Carlos

    2013-01-01

    Neutrophils are the most abundant leukocytes in peripheral blood. These cells are the first to appear at sites of inflammation and infection, thus becoming the first line of defense against invading microorganisms. Neutrophils possess important antimicrobial functions such as phagocytosis, release of lytic enzymes, and production of reactive oxygen species. In addition to these important defense functions, neutrophils perform other tasks in response to infection such as production of proinflammatory cytokines and inhibition of apoptosis. Cytokines recruit other leukocytes that help clear the infection, and inhibition of apoptosis allows the neutrophil to live longer at the site of infection. These functions are regulated at the level of transcription. However, because neutrophils are short-lived cells, the study of transcriptionally regulated responses in these cells cannot be performed with conventional reporter gene methods since there are no efficient techniques for neutrophil transfection. Here, we present a simple and efficient method that allows detection and quantification of nuclear factors in isolated and immunolabeled nuclei by flow cytometry. We describe techniques to isolate pure neutrophils from human peripheral blood, stimulate these cells with anti-receptor antibodies, isolate and immunolabel nuclei, and analyze nuclei by flow cytometry. The method has been successfully used to detect NF-κB and Elk-1 nuclear factors in nuclei from neutrophils and other cell types. Thus, this method represents an option for analyzing activation of transcription factors in isolated nuclei from a variety of cell types. PMID:23603868

  20. Multifaceted effects of Francisella tularensis on human neutrophil function and lifespan.

    PubMed

    Kinkead, Lauren C; Allen, Lee-Ann H

    2016-09-01

    Francisella tularensis in an intracellular bacterial pathogen that causes a potentially lethal disease called tularemia. Studies performed nearly 100 years ago revealed that neutrophil accumulation in infected tissues correlates directly with the extent of necrotic damage during F. tularensis infection. However, the dynamics and details of bacteria-neutrophil interactions have only recently been studied in detail. Herein, we review current understanding regarding the mechanisms that recruit neutrophils to F. tularensis-infected lungs, opsonization and phagocytosis, evasion and inhibition of neutrophil defense mechanisms, as well as the ability of F. tularensis to prolong neutrophil lifespan. In addition, we discuss distinctive features of the bacterium, including its ability to act at a distance to alter overall neutrophil responsiveness to exogenous stimuli, and the evidence which suggests that macrophages and neutrophils play distinct roles in tularemia pathogenesis, such that macrophages are major vehicles for intracellular growth and dissemination, whereas neutrophils drive tissue destruction by dysregulation of the inflammatory response. PMID:27558340

  1. Granulocyte colony-stimulating factor delays neutrophil apoptosis by inhibition of calpains upstream of caspase-3

    PubMed Central

    Drewniak, Agata; Groenewold, Vincent; van den Berg, Timo K.; Kuijpers, Taco W.

    2008-01-01

    Neutrophils have a very short life span and undergo apoptosis within 24 hours after leaving the bone marrow. Granulocyte colony-stimulating factor (G-CSF) is essential for the recruitment of fresh neutrophils from the bone marrow but also delays apoptosis of mature neutrophils. To determine the mechanism by which G-CSF inhibits neutrophil apoptosis, the kinetics of neutrophil apoptosis during 24 hours in the absence or presence of G-CSF were analyzed in vitro. G-CSF delayed neutrophil apoptosis for approximately 12 hours and inhibited caspase-9 and -3 activation, but had virtually no effect on caspase-8 and little effect on the release of proapoptotic proteins from the mitochondria. However, G-CSF strongly inhibited the activation of calcium-dependent cysteine proteases calpains, upstream of caspase-3, via apparent control of Ca2+-influx. Calpain inhibition resulted in the stabilization of the X-linked inhibitor of apoptosis (XIAP) and hence inhibited caspase-9 and -3 in human neutrophils. Thus, neutrophil apoptosis is controlled by G-CSF after initial activation of caspase-8 and mitochondrial permeabilization by the control of postmitochondrial calpain activity. PMID:18524991

  2. The Interleukin-17 Induced Activation and Increased Survival of Equine Neutrophils Is Insensitive to Glucocorticoids

    PubMed Central

    Murcia, Ruby Yoana; Vargas, Amandine; Lavoie, Jean-Pierre

    2016-01-01

    Background Glucocorticoids (GCs) are the most effective drugs for the treatment of human asthma. However, a subgroup of asthmatic patients with neutrophilic airway inflammation is insensitive to GCs. Interleukin-17 (IL-17), a cytokine upregulated in the airways of a subset of human asthmatic patients, contributes to the recruitment of neutrophils and induces a glucocorticoid resistance in human airway epithelial cells. We hypothesized that IL-17 similarly activates neutrophils and contributes to their persistence in the asthmatic airways in spite of glucocorticoid therapy. Objective To determine whether IL-17 directly activates neutrophils and whether this response is attenuated by GCs. Methods Neutrophils were isolated from the blood of horses and incubated in the presence of recombinant equine IL-17, LPS and dexamethasone. mRNA and protein expression of IL-17 receptors (IL-17RA/IL-17RC) were assessed by qPCR and immunoblot, respectively. Pro-inflammatory cytokine expression, cell viability and apoptosis were determined by qPCR, Trypan Blue exclusion test, and flow cytometry, respectively. Results Equine neutrophils express both IL-17RA and IL-17RC at the mRNA and protein levels. Neutrophil stimulation with IL-17 increases the mRNA expression of IL-8, which is not attenuated by dexamethasone (p = 0.409). Also, neutrophil viability is significantly increased (p<0.0001) by IL-17 in the presence of LPS when compared to LPS alone. Flow cytometry and light microscopy revealed that LPS-induced apoptosis is decreased by IL-17 (p = 0.02 and p = 0.006 respectively). Conclusion These results indicate that IL-17 directly activates equine neutrophils at 24 hours, and that the expression of IL-8 thus induced is not attenuated by GCs. Additionally, IL-17 increases neutrophil viability and decreases apoptosis. These findings suggest an important role of IL-17 in pulmonary persistence of neutrophils in the asthmatic airways. PMID:27138006

  3. Gliadin Induces Neutrophil Migration via Engagement of the Formyl Peptide Receptor, FPR1

    PubMed Central

    Liu, Song; Omatsu, Tatsushi; Janka-Junttila, Mirkka; Casolaro, Vincenzo; Reinecker, Hans-Christian; Parent, Carole A.; Fasano, Alessio

    2015-01-01

    Background Gliadin, the immunogenic component within gluten and trigger of celiac disease, is known to induce the production of Interleukin-8, a potent neutrophil-activating and chemoattractant chemokine. We sought to study the involvement of neutrophils in the early immunological changes following gliadin exposure. Methods Utilizing immunofluorescence microscopy and flow cytometry, the redistribution of major tight junction protein, Zonula occludens (ZO)-1, and neutrophil recruitment were assessed in duodenal tissues of gliadin-gavaged C57BL/6 wild-type and Lys-GFP reporter mice, respectively. Intravital microscopy with Lys-GFP mice allowed monitoring of neutrophil recruitment in response to luminal gliadin exposure in real time. In vitro chemotaxis assays were used to study murine and human neutrophil chemotaxis to gliadin, synthetic alpha-gliadin peptides and the neutrophil chemoattractant, fMet-Leu-Phe, in the presence or absence of a specific inhibitor of the fMet-Leu-Phe receptor-1 (FPR1), cyclosporine H. An irrelevant protein, zein, served as a control. Results Redistribution of ZO-1 and an influx of CD11b+Lys6G+ cells in the lamina propria of the small intestine were observed upon oral gavage of gliadin. In vivo intravital microscopy revealed a slowing down of GFP+ cells within the vessels and influx in the mucosal tissue within 2 hours after challenge. In vitro chemotaxis assays showed that gliadin strongly induced neutrophil migration, similar to fMet-Leu-Phe. We identified thirteen synthetic gliadin peptide motifs that induced cell migration. Blocking of FPR1 completely abrogated the fMet-Leu-Phe-, gliadin- and synthetic peptide-induced migration. Conclusions Gliadin possesses neutrophil chemoattractant properties similar to the classical neutrophil chemoattractant, fMet-Leu-Phe, and likewise uses FPR1 in the process. PMID:26378785

  4. Single platelets seal neutrophil-induced vascular breaches via GPVI during immune-complex-mediated inflammation in mice.

    PubMed

    Gros, Angèle; Syvannarath, Varouna; Lamrani, Lamia; Ollivier, Véronique; Loyau, Stéphane; Goerge, Tobias; Nieswandt, Bernhard; Jandrot-Perrus, Martine; Ho-Tin-Noé, Benoît

    2015-08-20

    Platelets protect vascular integrity during inflammation. Recent evidence suggests that this action is independent of thrombus formation and requires the engagement of glycoprotein VI (GPVI), but it remains unclear how platelets prevent inflammatory bleeding. We investigated whether platelets and GPVI act primarily by preventing detrimental effects of neutrophils using models of immune complex (IC)-mediated inflammation in mice immunodepleted in platelets and/or neutrophils or deficient in GPVI. Depletion of neutrophils prevented bleeding in thrombocytopenic and GPVI(-/-) mice during IC-mediated dermatitis. GPVI deficiency did not modify neutrophil recruitment, which was reduced by thrombocytopenia. Neutrophil cytotoxic activities were reduced in thrombocytopenic and GPVI(-/-) mice during IC-mediated inflammation. Intravital microscopy revealed that in this setting, intravascular binding sites for platelets were exposed by neutrophils, and GPVI supported the recruitment of individual platelets to these spots. Furthermore, the platelet secretory response accompanying IC-mediated inflammation was partly mediated by GPVI, and blocking of GPVI signaling impaired the vasculoprotective action of platelets. Together, our results show that GPVI plays a dual role in inflammation by enhancing neutrophil-damaging activities while supporting the activation and hemostatic adhesion of single platelets to neutrophil-induced vascular breaches. PMID:26036804

  5. Neutrophils rapidly transit inflamed lymphatic vessel endothelium via integrin-dependent proteolysis and lipoxin-induced junctional retraction.

    PubMed

    Rigby, David A; Ferguson, David J P; Johnson, Louise A; Jackson, David G

    2015-12-01

    Neutrophils are the first leukocyte population to be recruited from the circulation following tissue injury or infection, where they play key roles in host defense. However, recent evidence indicates recruited neutrophils can also enter lymph and shape adaptive immune responses downstream in draining lymph nodes. At present, the cellular mechanisms regulating neutrophil entry to lymphatic vessels and migration to lymph nodes are largely unknown. Here, we have investigated these events in an in vivo mouse Mycobacterium bovis bacillus Calmette-Guérin vaccination model, ex vivo mouse dermal explants, and in vitro Transwell system comprising monolayers of primary human dermal lymphatic endothelial cells. We demonstrate that neutrophils are reliant on endothelial activation for adhesion, initially via E-selectin and subsequently, by integrin-mediated binding to ICAM-1 and VCAM-1, combined with CXCL8-dependent chemotaxis. Moreover, we reveal that integrin-mediated neutrophil adhesion plays a pivotal role in subsequent transmigration by focusing the action of matrix metalloproteinases and the 15-lipoxygenase-1-derived chemorepellent 12(S)-hydroxyeicosatetraenoic acid at neutrophil:endothelial contact sites to induce transient endothelial junctional retraction and rapid, selective neutrophil trafficking. These findings reveal an unexpectedly intimate collaboration between neutrophils and the lymphatic vessel endothelium, in which these phagocytic leukocytes act as pathfinders for their own transit during inflammation. PMID:26216937

  6. Neutrophil rolling at high shear: flattening, catch bond behavior, tethers and slings.

    PubMed

    Sundd, Prithu; Pospieszalska, Maria K; Ley, Klaus

    2013-08-01

    Neutrophil recruitment to sites of inflammation involves neutrophil rolling along the inflamed endothelium in the presence of shear stress imposed by blood flow. Neutrophil rolling in post-capillary venules in vivo is primarily mediated by P-selectin on the endothelium binding to P-selectin glycoprotein ligand-1 (PSGL-1) constitutively expressed on neutrophils. Blood flow exerts a hydrodynamic drag on the rolling neutrophil which is partially or fully balanced by the adhesive forces generated in the P-selectin-PSGL-1 bonds. Rolling is the result of rapid formation and dissociation of P-selectin-PSGL-1 bonds at the center and rear of the rolling cell, respectively. Neutrophils roll stably on P-selectin in post-capillary venules in vivo and flow chambers in vitro at wall shear stresses greater than 6 dyn cm(-2). However, the mechanisms that enable neutrophils to roll at such high shear stress are not completely understood. In vitro and in vivo studies have led to the discovery of four potential mechanisms, viz. cell flattening, catch bond behavior, membrane tethers, and slings. Rolling neutrophils undergo flattening at high shear stress, which not only increases the size of the cell footprint but also reduces the hydrodynamic drag experienced by the rolling cell. P-selectin-PSGL-1 bonds behave as catch bonds at small detachment forces and thus become stronger with increasing force. Neutrophils rolling at high shear stress form membrane tethers which can be longer than the cell diameter and promote the survival of P-selectin-PSGL-1 bonds. Finally, neutrophils rolling at high shear stress form 'slings', which act as cell autonomous adhesive substrates and support step-wise peeling. Tethers and slings act together and contribute to the forces balancing the hydrodynamic drag. How the synergy between the four mechanisms leads to stable rolling at high shear stress is an area that needs further investigation. PMID:23141302

  7. Neutrophil rolling at high shear: flattening, catch bond behavior, tethers and slings

    PubMed Central

    Sundd, Prithu; Pospieszalska, Maria K.; Ley, Klaus

    2012-01-01

    Neutrophil recruitment to sites of inflammation involves neutrophil rolling along the inflamed endothelium in the presence of shear stress imposed by blood flow. Neutrophil rolling in post-capillary venules in vivo is primarily mediated by P-selectin on the endothelium binding to P-selectin glycoprotein ligand-1 (PSGL-1) constitutively expressed on neutrophils. Blood flow exerts a hydrodynamic drag on the rolling neutrophil which is partially or fully balanced by the adhesive forces generated in the P-selectin-PSGL-1 bonds. Rolling is the result of rapid formation and dissociation of P-selectin-PSGL-1 bonds at the center and rear of the rolling cell, respectively. Neutrophils roll stably on P-selectin in post-capillary venules in vivo and flow chambers in vitro at wall shear stresses greater than 6 dyn cm−2. However, the mechanisms that enable neutrophils to roll at such high shear stress are not completely understood. In vitro and in vivo studies have led to the discovery of four potential mechanisms, viz. cell flattening, catch bond behavior, membrane tethers, and slings. Rolling neutrophils undergo flattening at high shear stress, which not only increases the size of the cell footprint but also reduces the hydrodynamic drag experienced by the rolling cell. P-selectin-PSGL-1 bonds behave as catch bonds at small detachment forces and thus become stronger with increasing force. Neutrophils rolling at high shear stress form membrane tethers which can be longer than the cell diameter and promote the survival of P-selectin-PSGL-1 bonds. Finally, neutrophils rolling at high shear stress form slings, which act as cell autonomous adhesive substrates and support step-wise peeling. Tethers and slings act together and contribute to the forces balancing the hydrodynamic drag. How the synergy between the four mechanisms leads to stable rolling at high shear stress is an area that needs further investigation. PMID:23141302

  8. Neutrophil Elastase Inhibitors

    PubMed Central

    Groutas, William C.; Dou, Dengfeng; Alliston, Kevin R.

    2011-01-01

    Introduction Chronic obstructive pulmonary disease (COPD) constitutes a worldwide health problem. There is currently an urgent and unmet need for the development of small molecule therapeutics capable of blocking and/or reversing the progression of the disorder. Recent studies have greatly illuminated our understanding of the multiple pathogenic processes associated with COPD. Of paramount importance is the key role played by proteases, oxidative stress, apoptosis, and inflammation. Insights gained from these studies have made possible the exploration of new therapeutic approaches. Areas covered An overview of major developments in COPD research with emphasis on low molecular weight neutrophil elastase inhibitors is described in this review. Expert opinion Great strides have been made toward our understanding of the biochemical and cellular events associated with COPD. However, our knowledge regarding the inter-relationships among the multiple pathogenic mechanisms and their mediators involved is till limited. The problem is further compounded by the unavailability of suitable validated biomarkers for assessing the efficacy of potential therapeutic interventions. The complexity of COPD suggests that effective therapeutic interventions may require the administration of more than one agent such as, for instance, an HNE or MMP-12 inhibitor with an anti-inflammatory agent such as a phosphodiesterase-4 inhibitor, or a dual function agent capable of disrupting the cycle of proteolysis, apoptosis, inflammation and oxidative stress PMID:21235378

  9. AUTOINFLAMMATORY PUSTULAR NEUTROPHILIC DISEASES

    PubMed Central

    Naik, Haley B.; Cowen, Edward W.

    2013-01-01

    SYNOPSIS The inflammatory pustular dermatoses constitute a spectrum of non-infectious conditions ranging from localized involvement to generalized disease with associated acute systemic inflammation and multi-organ involvement. Despite the variability in extent and severity of cutaneous presentation, each of these diseases is characterized by non-infectious neutrophilic intra-epidermal microabscesses. Many share systemic findings including fever, elevated inflammatory markers, inflammatory bowel disease and/or osteoarticular involvement, suggesting potential common pathogenic links (Figure 1). The recent discoveries of several genes responsible for heritable pustular diseases have revealed a distinct link between pustular skin disease and regulation of innate immunity. These genetic advances have led to a deeper exploration of common pathways in pustular skin disease and offer the potential for a new era of biologic therapy which targets these shared pathways. This chapter provides a new categorization of inflammatory pustular dermatoses in the context of recent genetic and biologic insights. We will discuss recently-described monogenic diseases with pustular phenotypes, including deficiency of IL-1 receptor antagonist (DIRA), deficiency of the IL-36 receptor antagonist (DITRA), CARD14-associated pustular psoriasis (CAMPS), and pyogenic arthritis, pyoderma gangrenosum, acne (PAPA). We will then discuss how these new genetic advancements may inform how we view previously described pustular diseases, including pustular psoriasis and its clinical variants, with a focus on historical classification by clinical phenotype. PMID:23827244

  10. Role of osteopontin in hepatic neutrophil infiltration during alcoholic steatohepatitis

    SciTech Connect

    Apte, Udayan M.; Banerjee, Atrayee; McRee, Rachel; Wellberg, Elizabeth; Ramaiah, Shashi K. . E-mail: sramaiah@cvm.tamu.edu

    2005-08-22

    Alcoholic liver disease (ALD) is a major complication of heavy alcohol (EtOH) drinking and is characterized by three progressive stages of pathology: steatosis, steatohepatitis, and fibrosis/cirrhosis. Alcoholic steatosis (AS) is the initial stage of ALD and consists of fat accumulation in the liver accompanied by minimal liver injury. AS is known to render the hepatocytes increasingly sensitive to toxicants such as bacterial endotoxin (LPS). Alcoholic steatohepatitis (ASH), the second and rate-limiting step in the progression of ALD, is characterized by hepatic fat accumulation, neutrophil infiltration, and neutrophil-mediated parenchymal injury. However, the pathogenesis of ASH is poorly defined. It has been theorized that the pathogenesis of ASH involves interaction of increased circulating levels of LPS with hepatocytes being rendered highly sensitive to LPS due to heavy EtOH consumption. We hypothesize that osteopontin (OPN), a matricellular protein (MCP), plays an important role in the hepatic neutrophil recruitment due to its enhanced expression during the early phase of ALD (AS and ASH). To study the role of OPN in the pathogenesis of ASH, we induced AS in male Sprague-Dawley rats by feeding EtOH-containing Lieber-DeCarli liquid diet for 6 weeks. AS rats experienced extensive fat accumulation and minimal liver injury. Moderate induction in OPN was observed in AS group. ASH was induced by feeding male Sprague-Dawley rats EtOH-containing Lieber-DeCarli liquid diet for 6 weeks followed by LPS injection. The ASH rats had substantial neutrophil infiltration, coagulative oncotic necrosis, and developed higher liver injury. Significant increases in the hepatic and circulating levels of OPN was observed in the ASH rats. Higher levels of the active, thrombin-cleaved form of OPN in the liver in ASH group correlated remarkably with hepatic neutrophil infiltration. Finally, correlative studies between OPN and hepatic neutrophil infiltration was corroborated in a simple

  11. Ibuprofen inhibits adhesion-dependent neutrophil response by a glycoprotein-unrelated mechanism.

    PubMed

    Ottonello, L; Pastorino, G; Dapino, P; Beretta, A; Dallegri, F

    1992-01-01

    The anti-inflammatory drug ibuprofen was found to inhibit neutrophil aggregation and chemotaxis, triggered by the chemotactic factor N-formyl-methionyl-leucyl-phenylalanine (FMLP). The drug did not modify the surface expression of the glycoprotein CD11b-CD18, required for both aggregation and chemotaxis. Consistent with this finding, ibuprofen did not affect the release of lactoferrin from secondary granules which contain CD11b-CD18 molecules in their membranes. As the drug failed to interfere with the neutrophil oxidant production and primary granule release, the results suggest that it acts primarily at the initial steps of the neutrophil response during inflammation, i.e. the cell recruitment at inflamed tissue sites. Moreover, the data prove that adhesion-dependent neutrophil responses required cell processes independent of CD11b-CD18 but controlled, at least in part, by ibuprofen-inhibitable pathways. PMID:1350975

  12. Do neutrophil extracellular traps contribute to the heightened risk of thrombosis in inflammatory diseases?

    PubMed Central

    Rao, Ashish N; Kazzaz, Nayef M; Knight, Jason S

    2015-01-01

    Thrombotic events, both arterial and venous, are a major health concern worldwide. Further, autoimmune diseases, such as systemic lupus erythematosus, anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis, and antiphospholipid syndrome, predispose to thrombosis, and thereby push the risk for these morbid events even higher. In recent years, neutrophils have been identified as important players in both arterial and venous thrombosis. Specifically, chromatin-based structures called neutrophil extracellular traps (NETs) play a key role in activating the coagulation cascade, recruiting platelets, and serving as scaffolding upon which the thrombus can be assembled. At the same time, neutrophils and NETs are emerging as important mediators of pathogenic inflammation in the aforementioned autoimmune diseases. Here, we first review the general role of NETs in thrombosis. We then posit that exaggerated NET release contributes to the prothrombotic diatheses of systemic lupus erythematosus, ANCA-associated vasculitis, and antiphospholipid syndrome. PMID:26730289

  13. Real-time detection of implant-associated neutrophil responses using a formyl peptide receptor-targeting NIR nanoprobe

    PubMed Central

    Zhou, Jun; Tsai, Yi-Ting; Weng, Hong; Tang, Ewin N; Nair, Ashwin; Davé, Digant P; Tang, Liping

    2012-01-01

    Neutrophils play an important role in implant-mediated inflammation and infection. Unfortunately, current methods which monitor neutrophil activity, including enzyme measurements and histological evaluation, require many animals and cannot be used to accurately depict the dynamic cellular responses. To understand the neutrophil interactions around implant-mediated inflammation and infection it is critical to develop methods which can monitor in vivo cellular activity in real time. In this study, formyl peptide receptor (FPR)-targeting near-infrared nanoprobes were fabricated. This was accomplished by conjugating near-infrared dye with specific peptides having a high affinity to the FPRs present on activated neutrophils. The ability of FPR-targeting nanoprobes to detect and quantify activated neutrophils was assessed both in vitro and in vivo. As expected, FPR-targeting nanoprobes preferentially accumulated on activated neutrophils in vitro. Following transplantation, FPR-targeting nanoprobes preferentially accumulated at the biomaterial implantation site. Equally important, a strong relationship was observed between the extent of fluorescence intensity in vivo and the number of recruited neutrophils at the implantation site. Furthermore, FPR-targeting nanoprobes may be used to detect and quantify the number of neutrophils responding to a catheter-associated infection. The results show that FPR-targeting nanoprobes may serve as a powerful tool to monitor and measure the extent of neutrophil responses to biomaterial implants in vivo. PMID:22619542

  14. Gαi2 and Gαi3 Differentially Regulate Arrest from Flow and Chemotaxis in Mouse Neutrophils.

    PubMed

    Kuwano, Yoshihiro; Adler, Micha; Zhang, Hong; Groisman, Alex; Ley, Klaus

    2016-05-01

    Leukocyte recruitment to inflammation sites progresses in a multistep cascade. Chemokines regulate multiple steps of the cascade, including arrest, transmigration, and chemotaxis. The most important chemokine receptor in mouse neutrophils is CXCR2, which couples through Gαi2- and Gαi3-containing heterotrimeric G proteins. Neutrophils arrest in response to CXCR2 stimulation. This is defective in Gαi2-deficient neutrophils. In this study, we show that Gαi3-deficient neutrophils showed reduced transmigration but normal arrest in mice. We also tested Gαi2- or Gαi3-deficient neutrophils in a CXCL1 gradient generated by a microfluidic device. Gαi3-, but not Gαi2-, deficient neutrophils showed significantly reduced migration and directionality. This was confirmed in a model of sterile inflammation in vivo. Gαi2-, but not Gαi3-, deficient neutrophils showed decreased Ca(2+) flux in response to CXCR2 stimulation. Conversely, Gαi3-, but not Gαi2-, deficient neutrophils exhibited reduced AKT phosphorylation upon CXCR2 stimulation. We conclude that Gαi2 controls arrest and Gαi3 controls transmigration and chemotaxis in response to chemokine stimulation of neutrophils. PMID:26976957

  15. BLT1 signalling protects the liver against acetaminophen hepatotoxicity by preventing excessive accumulation of hepatic neutrophils

    PubMed Central

    Kojo, Ken; Ito, Yoshiya; Eshima, Koji; Nishizawa, Nobuyuki; Ohkubo, Hirotoki; Yokomizo, Takehiko; Shimizu, Takao; Watanabe, Masahiko; Majima, Masataka

    2016-01-01

    Leukotriene B4 (LTB4) is a potent chemoattractant for neutrophils. Signalling of LTB4 receptor type 1 (BLT1) has pro-inflammatory functions through neutrophil recruitment. In this study, we investigated whether BLT1 signalling plays a role in acetaminophen (APAP)-induced liver injury by affecting inflammatory responses including the accumulation of hepatic neutrophils. BLT1-knockout (BLT1−/−) mice and their wild-type (WT) counterparts were subjected to a single APAP overdose (300 mg/kg), and various parameters compared within 24 h after treatment. Compared with WT mice, BLT1−/− mice exhibited exacerbation of APAP-induced liver injury as evidenced by enhancement of alanine aminotransferase level, necrotic area, hepatic neutrophil accumulation, and expression of cytokines and chemokines. WT mice co-treated with APAP and ONO-0457, a specific antagonist for BLT1, displayed amplification of the injury, and similar results to those observed in BLT1−/− mice. Hepatic neutrophils in BLT1−/− mice during APAP hepatotoxicity showed increases in the production of reactive oxygen species and matrix metalloproteinase-9. Administration of isolated BLT1-deficient neutrophils into WT mice aggravated the liver injury elicited by APAP. These results demonstrate that BLT1 signalling dampens the progression of APAP hepatotoxicity through inhibiting an excessive accumulation of activated neutrophils. The development of a specific agonist for BLT1 could be useful for the prevention of APAP hepatotoxicity. PMID:27404729

  16. Rapid and label-free microfluidic neutrophil purification and phenotyping in diabetes mellitus.

    PubMed

    Hou, Han Wei; Petchakup, Chayakorn; Tay, Hui Min; Tam, Zhi Yang; Dalan, Rinkoo; Chew, Daniel Ek Kwang; Li, King Ho Holden; Boehm, Bernhard O

    2016-01-01

    Advanced management of dysmetabolic syndromes such as diabetes will benefit from a timely mechanistic insight enabling personalized medicine approaches. Herein, we present a rapid microfluidic neutrophil sorting and functional phenotyping strategy for type 2 diabetes mellitus (T2DM) patients using small blood volumes (fingerprick ~100 μL). The developed inertial microfluidics technology enables single-step neutrophil isolation (>90% purity) without immuno-labeling and sorted neutrophils are used to characterize their rolling behavior on E-selectin, a critical step in leukocyte recruitment during inflammation. The integrated microfluidics testing methodology facilitates high throughput single-cell quantification of neutrophil rolling to detect subtle differences in speed distribution. Higher rolling speed was observed in T2DM patients (P < 0.01) which strongly correlated with neutrophil activation, rolling ligand P-selectin glycoprotein ligand 1 (PSGL-1) expression, as well as established cardiovascular risk factors (cholesterol, high-sensitive C-reactive protein (CRP) and HbA1c). Rolling phenotype can be modulated by common disease risk modifiers (metformin and pravastatin). Receiver operating characteristics (ROC) and principal component analysis (PCA) revealed neutrophil rolling as an important functional phenotype in T2DM diagnostics. These results suggest a new point-of-care testing methodology, and neutrophil rolling speed as a functional biomarker for rapid profiling of dysmetabolic subjects in clinical and patient-oriented settings. PMID:27381673

  17. Neutrophils support lung colonization of metastasis-initiating breast cancer cells.

    PubMed

    Wculek, Stefanie K; Malanchi, Ilaria

    2015-12-17

    Despite progress in the development of drugs that efficiently target cancer cells, treatments for metastatic tumours are often ineffective. The now well-established dependency of cancer cells on their microenvironment suggests that targeting the non-cancer-cell component of the tumour might form a basis for the development of novel therapeutic approaches. However, the as-yet poorly characterized contribution of host responses during tumour growth and metastatic progression represents a limitation to exploiting this approach. Here we identify neutrophils as the main component and driver of metastatic establishment within the (pre-)metastatic lung microenvironment in mouse breast cancer models. Neutrophils have a fundamental role in inflammatory responses and their contribution to tumorigenesis is still controversial. Using various strategies to block neutrophil recruitment to the pre-metastatic site, we demonstrate that neutrophils specifically support metastatic initiation. Importantly, we find that neutrophil-derived leukotrienes aid the colonization of distant tissues by selectively expanding the sub-pool of cancer cells that retain high tumorigenic potential. Genetic or pharmacological inhibition of the leukotriene-generating enzyme arachidonate 5-lipoxygenase (Alox5) abrogates neutrophil pro-metastatic activity and consequently reduces metastasis. Our results reveal the efficacy of using targeted therapy against a specific tumour microenvironment component and indicate that neutrophil Alox5 inhibition may limit metastatic progression. PMID:26649828

  18. Human neutrophils: Their role in cancer and relation to myeloid-derived suppressor cells.

    PubMed

    Moses, Katrin; Brandau, Sven

    2016-04-01

    Increased frequencies of peripheral blood neutrophils as well as tumor-infiltrating (associated) neutrophils (TAN) have been observed in many tumor entities. Although the most frequent cell type in the peripheral blood, neutrophils are outnumbered by other leukocyte subsets in the tumor microenvironment. Nevertheless, a number of recent meta-analyses identified TAN as well as high neutrophil-lymphocyte ratio in the blood as one of the most powerful immunologic prognostic parameters in human oncology. This clinical impact is based on an intense bidirectional crosstalk of neutrophils and tumor cells resulting in changes in neutrophil as well as tumor cell biology. These changes eventually lead to TAN equipped with various tumor promoting features, which enhance angiogenesis, cancer cell invasion and metastasis. Many of the pro-tumor features of TAN are shared with PMN-MDSC (myeloid-derived suppressor cells). Consequently, the distinction of these two cell populations is a matter of intensive debate and also specifically discussed in this article. The importance of neutrophils in cancer progression has triggered numerous efforts to therapeutically target these cells. Current strategies in this area focus on the inhibition of either TAN recruitment or pro-tumorigenic function. PMID:27067179

  19. BLT1 signalling protects the liver against acetaminophen hepatotoxicity by preventing excessive accumulation of hepatic neutrophils.

    PubMed

    Kojo, Ken; Ito, Yoshiya; Eshima, Koji; Nishizawa, Nobuyuki; Ohkubo, Hirotoki; Yokomizo, Takehiko; Shimizu, Takao; Watanabe, Masahiko; Majima, Masataka

    2016-01-01

    Leukotriene B4 (LTB4) is a potent chemoattractant for neutrophils. Signalling of LTB4 receptor type 1 (BLT1) has pro-inflammatory functions through neutrophil recruitment. In this study, we investigated whether BLT1 signalling plays a role in acetaminophen (APAP)-induced liver injury by affecting inflammatory responses including the accumulation of hepatic neutrophils. BLT1-knockout (BLT1(-/-)) mice and their wild-type (WT) counterparts were subjected to a single APAP overdose (300 mg/kg), and various parameters compared within 24 h after treatment. Compared with WT mice, BLT1(-/-) mice exhibited exacerbation of APAP-induced liver injury as evidenced by enhancement of alanine aminotransferase level, necrotic area, hepatic neutrophil accumulation, and expression of cytokines and chemokines. WT mice co-treated with APAP and ONO-0457, a specific antagonist for BLT1, displayed amplification of the injury, and similar results to those observed in BLT1(-/-) mice. Hepatic neutrophils in BLT1(-/-) mice during APAP hepatotoxicity showed increases in the production of reactive oxygen species and matrix metalloproteinase-9. Administration of isolated BLT1-deficient neutrophils into WT mice aggravated the liver injury elicited by APAP. These results demonstrate that BLT1 signalling dampens the progression of APAP hepatotoxicity through inhibiting an excessive accumulation of activated neutrophils. The development of a specific agonist for BLT1 could be useful for the prevention of APAP hepatotoxicity. PMID:27404729

  20. Rapid and label-free microfluidic neutrophil purification and phenotyping in diabetes mellitus

    NASA Astrophysics Data System (ADS)

    Hou, Han Wei; Petchakup, Chayakorn; Tay, Hui Min; Tam, Zhi Yang; Dalan, Rinkoo; Chew, Daniel Ek Kwang; Li, King Ho Holden; Boehm, Bernhard O.

    2016-07-01

    Advanced management of dysmetabolic syndromes such as diabetes will benefit from a timely mechanistic insight enabling personalized medicine approaches. Herein, we present a rapid microfluidic neutrophil sorting and functional phenotyping strategy for type 2 diabetes mellitus (T2DM) patients using small blood volumes (fingerprick ~100 μL). The developed inertial microfluidics technology enables single-step neutrophil isolation (>90% purity) without immuno-labeling and sorted neutrophils are used to characterize their rolling behavior on E-selectin, a critical step in leukocyte recruitment during inflammation. The integrated microfluidics testing methodology facilitates high throughput single-cell quantification of neutrophil rolling to detect subtle differences in speed distribution. Higher rolling speed was observed in T2DM patients (P < 0.01) which strongly correlated with neutrophil activation, rolling ligand P-selectin glycoprotein ligand 1 (PSGL-1) expression, as well as established cardiovascular risk factors (cholesterol, high-sensitive C-reactive protein (CRP) and HbA1c). Rolling phenotype can be modulated by common disease risk modifiers (metformin and pravastatin). Receiver operating characteristics (ROC) and principal component analysis (PCA) revealed neutrophil rolling as an important functional phenotype in T2DM diagnostics. These results suggest a new point-of-care testing methodology, and neutrophil rolling speed as a functional biomarker for rapid profiling of dysmetabolic subjects in clinical and patient-oriented settings.

  1. Neutrophil Crawling in Capillaries; A Novel Immune Response to Staphylococcus aureus

    PubMed Central

    Harding, Mark Geoffrey; Zhang, Kunyan; Conly, John; Kubes, Paul

    2014-01-01

    Methicillin-resistant Staphylococcus aureus (MRSA), particularly the USA300 strain, is a highly virulent pathogen responsible for an increasing number of skin and soft tissue infections globally. Furthermore, MRSA-induced soft tissue infections can rapidly progress into life-threatening conditions, such as sepsis and necrotizing fasciitis. The importance of neutrophils in these devastating soft tissue infections remains ambiguous, partly because of our incomplete understanding of their behaviour. Spinning disk confocal microscopy was used to visualize the behaviour of GR1-labelled neutrophils in subcutaneous tissue in response to GFP-expressing MRSA attached to a foreign particle (agarose bead). We observed significant directional neutrophil recruitment towards the S. aureus agarose bead but not a control agarose bead. A significant increase in neutrophil crawling within the capillaries surrounding the infectious nidus was noted, with impaired capillary perfusion in these vessels and increased parenchymal cell death. No neutrophils were able to emigrate from capillaries. The crawling within these capillaries was mediated by the β2 and α4 integrins and blocking these integrins 2 hours post infection eliminated neutrophil crawling, improved capillary perfusion, reduced cell death and reduced lesion size. Blocking prior to infection increased pathology. Neutrophil crawling within capillaries during MRSA soft tissue infections, while potentially contributing to walling off or preventing early dissemination of the pathogen, resulted in impaired perfusion and increased tissue injury with time. PMID:25299673

  2. How neutrophil extracellular traps orchestrate the local immune response in gout.

    PubMed

    Maueröder, Christian; Kienhöfer, Deborah; Hahn, Jonas; Schauer, Christine; Manger, Bernhard; Schett, Georg; Herrmann, Martin; Hoffmann, Markus H

    2015-07-01

    Neutrophil granulocytes possess a large arsenal of pro-inflammatory substances and mechanisms that empower them to drive local acute immune reactions to invading microorganisms or endogenous inflammatory triggers. The use of this armory needs to be tightly controlled to avoid chronic inflammation and collateral tissue damage. In gout, inflammation arises from precipitation of uric acid in the form of needle-shaped monosodium urate crystals. Inflammasome activation by these crystals in local immune cells results in a rapid and dramatic recruitment of neutrophils. This neutrophil influx is accompanied by the infamously intense clinical symptoms of inflammation during an acute gout attack. Neutrophilic inflammation however is equipped with a built-in safeguard; activated neutrophils form neutrophil extracellular traps (NETs). At the very high neutrophil densities that occur at the site of inflammation, NETs build aggregates that densely pack the monosodium urate (MSU) crystals and trap and degrade pro-inflammatory mediators by inherent proteases. Local removal of cytokines and chemokines by aggregated NETs explains how acute inflammation can stop in the consistent presence of the inflammatory trigger. Aggregated NETs resemble early stages of the typical large MSU deposits that constitute the pathognomonic structures of gout, tophi. Although tophi contribute to muscosceletal damage and mortality in patients with chronic gout, they can therefore be considered as a payoff that is necessary to silence the intense inflammatory response during acute gout. PMID:26002146

  3. Rapid and label-free microfluidic neutrophil purification and phenotyping in diabetes mellitus

    PubMed Central

    Hou, Han Wei; Petchakup, Chayakorn; Tay, Hui Min; Tam, Zhi Yang; Dalan, Rinkoo; Chew, Daniel Ek Kwang; Li, King Ho Holden; Boehm, Bernhard O.

    2016-01-01

    Advanced management of dysmetabolic syndromes such as diabetes will benefit from a timely mechanistic insight enabling personalized medicine approaches. Herein, we present a rapid microfluidic neutrophil sorting and functional phenotyping strategy for type 2 diabetes mellitus (T2DM) patients using small blood volumes (fingerprick ~100 μL). The developed inertial microfluidics technology enables single-step neutrophil isolation (>90% purity) without immuno-labeling and sorted neutrophils are used to characterize their rolling behavior on E-selectin, a critical step in leukocyte recruitment during inflammation. The integrated microfluidics testing methodology facilitates high throughput single-cell quantification of neutrophil rolling to detect subtle differences in speed distribution. Higher rolling speed was observed in T2DM patients (P < 0.01) which strongly correlated with neutrophil activation, rolling ligand P-selectin glycoprotein ligand 1 (PSGL-1) expression, as well as established cardiovascular risk factors (cholesterol, high-sensitive C-reactive protein (CRP) and HbA1c). Rolling phenotype can be modulated by common disease risk modifiers (metformin and pravastatin). Receiver operating characteristics (ROC) and principal component analysis (PCA) revealed neutrophil rolling as an important functional phenotype in T2DM diagnostics. These results suggest a new point-of-care testing methodology, and neutrophil rolling speed as a functional biomarker for rapid profiling of dysmetabolic subjects in clinical and patient-oriented settings. PMID:27381673

  4. Apoptotic cell clearance of Leishmania major-infected neutrophils by dendritic cells inhibits CD8⁺ T-cell priming in vitro by Mer tyrosine kinase-dependent signaling.

    PubMed

    Ribeiro-Gomes, F L; Romano, A; Lee, S; Roffê, E; Peters, N C; Debrabant, A; Sacks, D

    2015-01-01

    Neutrophils are the predominant recruited and infected cells during the early stages of Leishmania major infection in the skin, and depletion of neutrophils promotes immunity to infection transmitted by sand fly bite. In order to better understand how the acute neutrophilic response suppresses immunity, we assessed the consequences of the interaction between neutrophils recovered from the skin-inoculation site and bone marrow-derived dendritic cells (DCs) in vitro. The capture of infected, apoptotic neutrophils by the DCs completely inhibited their cross-presentation function that was dependent on engagement of the receptor tyrosine kinase Mer on the DCs. The capture of uninfected neutrophils, or neutrophils infected with Toxoplasma gondii, had only slight immunomodulatory effects. These studies define the clearance of infected, apoptotic neutrophils by DCs and Mer receptor signaling as central to the early immune evasion strategies of L. major, with relevance to other vector-borne pathogens delivered by bite to the skin. PMID:26658192

  5. Adjustment to Recruit Training.

    ERIC Educational Resources Information Center

    Anderson, Betty S.

    The thesis examines problems of adjustment encountered by new recruits entering the military services. Factors affecting adjustment are discussed: the recruit training staff and environment, recruit background characteristics, the military's image, the changing values and motivations of today's youth, and the recruiting process. Sources of…

  6. ICAM-1 mediates surface contact between neutrophils and keratocytes following corneal epithelial abrasion in the mouse

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Corneal epithelial abrasion elicits an inflammatory response involving neutrophil (PMN) recruitment from the limbal vessels into the corneal stroma. These migrating PMNs make surface contact with collagen and stromal keratocytes. Using mice deficient in PMN integrin CD18, we previously showed that P...

  7. Neutrophil roles in left ventricular remodeling following myocardial infarction

    PubMed Central

    2013-01-01

    Polymorphonuclear granulocytes (PMNs; neutrophils) serve as key effector cells in the innate immune system and provide the first line of defense against invading microorganisms. In addition to producing inflammatory cytokines and chemokines and undergoing a respiratory burst that stimulates the release of reactive oxygen species, PMNs also degranulate to release components that kill pathogens. Recently, neutrophil extracellular traps have been shown to be an alternative way to trap microorganisms and contain infection. PMN-derived granule components are also involved in multiple non-infectious inflammatory processes, including the response to myocardial infarction (MI). In this review, we will discuss the biological characteristics, recruitment, activation, and removal of PMNs, as well as the roles of PMN-derived granule proteins in inflammation and innate immunity, focusing on the MI setting when applicable. We also discuss future perspectives that will direct research in PMN biology. PMID:23731794

  8. Neutrophils and Granulocytic MDSC: The Janus God of Cancer Immunotherapy.

    PubMed

    Zilio, Serena; Serafini, Paolo

    2016-01-01

    Neutrophils are the most abundant circulating blood cell type in humans, and are the first white blood cells recruited at the inflammation site where they orchestrate the initial immune response. Although their presence at the tumor site was recognized in the 1970s, until recently these cells have been neglected and considered to play just a neutral role in tumor progression. Indeed, in recent years neutrophils have been recognized to play a dual role in tumor development by either assisting the growth, angiogenesis, invasion, and metastasis or by exerting tumoricidal action directly via the secretion of antitumoral compounds, or indirectly via the orchestration of antitumor immunity. Understanding the biology of these cells and influencing their polarization in the tumor micro- and macro-environment may be the key for the development of new therapeutic strategies, which may finally hold the promise of an effective immunotherapy for cancer. PMID:27618112

  9. Interleukin-17A and Neutrophils in a Murine Model of Bird-Related Hypersensitivity Pneumonitis

    PubMed Central

    Ishizuka, Masahiro; Miyazaki, Yasunari; Masuo, Masahiro; Suhara, Kozo; Tateishi, Tomoya; Yasui, Makito; Inase, Naohiko

    2015-01-01

    Hypersensitivity pneumonitis (HP) is an immune mediated lung disease induced by the repeated inhalation of a wide variety of antigens. Bird-related hypersensitivity pneumonitis (BRHP) is one of the most common forms of HP in human and results from the inhalation of avian antigens. The findings of a recent clinical analysis suggest that in addition to Th1 factors, the levels of interleukin(IL)-17 and IL-17-associated transcripts are increased in the setting of HP, and that both IL-17A and neutrophils are crucial for the development of pulmonary inflammation in murine models of HP. Our objectives were to investigate the roles of IL-17A and neutrophils in granuloma-forming inflammation in an acute HP model. We developed a mouse model of acute BRHP using pigeon dropping extract. We evaluated the process of granuloma formation and the roles of both IL-17A and neutrophils in a model. We found that the neutralization of IL-17A by the antibody attenuated granuloma formation and the recruitment of neutrophils, and also decreased the expression level of chemokine(C-X-C motif) ligand 5 (CXCL5) in the acute HP model. We confirmed that most of the neutrophils in the acute HP model exhibited immunoreactivity to the anti-IL-17 antibody. We have identified the central roles of both IL-17A and neutrophils in the pathogenesis of granuloma formation in acute HP. We have also assumed that neutrophils are an important source of IL-17A in an acute HP model, and that the IL-17A-CXCL5 pathway may be responsible for the recruitment of neutrophils. PMID:26367130

  10. Neutrophils do not mediate the pathophysiological sequelae of Cryptosporidium parvum infection in neonatal piglets.

    PubMed

    Zadrozny, Leah M; Stauffer, Stephen H; Armstrong, Martha U; Jones, Samuel L; Gookin, Jody L

    2006-10-01

    Cryptosporidium parvum is a minimally invasive protozoal pathogen of intestinal epithelium that results in villus atrophy, mucosal lipid peroxidation, diarrhea, and diminished barrier function. Influx of neutrophils is a consistent feature of human and animal cryptosporidiosis, and yet their contribution to the pathological sequelae of infection has not been investigated. Accordingly, we used an established neonatal piglet model of C. parvum infection to examine the role of neutrophils in disease pathogenesis by inhibiting their recruitment and activation in vivo using a monoclonal anti-CD18 antibody. Infected piglets were treated daily with anti-CD18 or isotype control immunoglobulin G and euthanized at peak infection, at which time neutrophil infiltrates, lipid peroxidation, severity of infection, and intestinal barrier function were quantified. C. parvum infection resulted in a significant increase in mucosal neutrophil myeloperoxidase activity that was prevented by treatment of piglets with anti-CD18 antibody. Neutrophil recruitment was dependent on mucosal superoxide formation (prevented by treatment of infected piglets with superoxide dismutase). Neutrophils did not contribute to peroxynitrite formation or peroxidative injury of C. parvum-infected mucosa and had no impact on the severity of epithelial infection, villus atrophy, or diarrhea. The presence of neutrophils in C. parvum-infected mucosa was associated with enhanced barrier function that could not be attributed to mucosal elaboration of prostaglandins or stimulation of their synthesis. These studies are the first to demonstrate that neutrophilic inflammation arising in response to infection by a noninvasive epithelial pathogen results in physiologic rather than pathological effects in vivo. PMID:16988224

  11. Neutrophils Do Not Mediate the Pathophysiological Sequelae of Cryptosporidium parvum Infection in Neonatal Piglets

    PubMed Central

    Zadrozny, Leah M.; Stauffer, Stephen H.; Armstrong, Martha U.; Jones, Samuel L.; Gookin, Jody L.

    2006-01-01

    Cryptosporidium parvum is a minimally invasive protozoal pathogen of intestinal epithelium that results in villus atrophy, mucosal lipid peroxidation, diarrhea, and diminished barrier function. Influx of neutrophils is a consistent feature of human and animal cryptosporidiosis, and yet their contribution to the pathological sequelae of infection has not been investigated. Accordingly, we used an established neonatal piglet model of C. parvum infection to examine the role of neutrophils in disease pathogenesis by inhibiting their recruitment and activation in vivo using a monoclonal anti-CD18 antibody. Infected piglets were treated daily with anti-CD18 or isotype control immunoglobulin G and euthanized at peak infection, at which time neutrophil infiltrates, lipid peroxidation, severity of infection, and intestinal barrier function were quantified. C. parvum infection resulted in a significant increase in mucosal neutrophil myeloperoxidase activity that was prevented by treatment of piglets with anti-CD18 antibody. Neutrophil recruitment was dependent on mucosal superoxide formation (prevented by treatment of infected piglets with superoxide dismutase). Neutrophils did not contribute to peroxynitrite formation or peroxidative injury of C. parvum-infected mucosa and had no impact on the severity of epithelial infection, villus atrophy, or diarrhea. The presence of neutrophils in C. parvum-infected mucosa was associated with enhanced barrier function that could not be attributed to mucosal elaboration of prostaglandins or stimulation of their synthesis. These studies are the first to demonstrate that neutrophilic inflammation arising in response to infection by a noninvasive epithelial pathogen results in physiologic rather than pathological effects in vivo. PMID:16988224

  12. Role of G-CSF in monophosphoryl lipid A-mediated augmentation of neutrophil functions after burn injury.

    PubMed

    Bohannon, Julia K; Luan, Liming; Hernandez, Antonio; Afzal, Aqeela; Guo, Yin; Patil, Naeem K; Fensterheim, Benjamin; Sherwood, Edward R

    2016-04-01

    Infection is the leading cause of death in severely burned patients that survive the acute phase of injury. Neutrophils are the first line of defense against infections, but hospitalized burn patients frequently cannot mount an appropriate innate response to infection. Thus, immune therapeutic approaches aimed at improving neutrophil functions after burn injury may be beneficial. Prophylactic treatment with the TLR4 agonist monophosphoryl lipid A is known to augment resistance to infection by enhancing neutrophil recruitment and facilitating bacterial clearance. This study aimed to define mechanisms by which monophosphoryl lipid A treatment improves bacterial clearance and survival in a model of burn-wound sepsis. Burn-injured mice were treated with monophosphoryl lipid A or vehicle, and neutrophil mobilization was evaluated in the presence or absence ofPseudomonas aeruginosainfection. Monophosphoryl lipid A treatment induced significant mobilization of neutrophils from the bone marrow into the blood and sites of infection. Neutrophil mobilization was associated with decreased bone marrow neutrophil CXCR4 expression and increased plasma G-CSF concentrations. Neutralization of G-CSF before monophosphoryl lipid A administration blocked monophosphoryl lipid A-induced expansion of bone marrow myeloid progenitors and mobilization of neutrophils into the blood and their recruitment to the site of infection. G-CSF neutralization ablated the enhanced bacterial clearance and survival benefit endowed by monophosphoryl lipid A in burn-wound-infected mice. Our findings provide convincing evidence that monophosphoryl lipid A-induced G-CSF facilitates early expansion, mobilization, and recruitment of neutrophils to the site of infection after burn injury, allowing for a robust immune response to infection. PMID:26538529

  13. Neutrophil ageing is regulated by the microbiome.

    PubMed

    Zhang, Dachuan; Chen, Grace; Manwani, Deepa; Mortha, Arthur; Xu, Chunliang; Faith, Jeremiah J; Burk, Robert D; Kunisaki, Yuya; Jang, Jung-Eun; Scheiermann, Christoph; Merad, Miriam; Frenette, Paul S

    2015-09-24

    Blood polymorphonuclear neutrophils provide immune protection against pathogens, but may also promote tissue injury in inflammatory diseases. Although neutrophils are generally considered to be a relatively homogeneous population, evidence for heterogeneity is emerging. Under steady-state conditions, neutrophil heterogeneity may arise from ageing and replenishment by newly released neutrophils from the bone marrow. Aged neutrophils upregulate CXCR4, a receptor allowing their clearance in the bone marrow, with feedback inhibition of neutrophil production via the IL-17/G-CSF axis, and rhythmic modulation of the haematopoietic stem-cell niche. The aged subset also expresses low levels of L-selectin. Previous studies have suggested that in vitro-aged neutrophils exhibit impaired migration and reduced pro-inflammatory properties. Here, using in vivo ageing analyses in mice, we show that neutrophil pro-inflammatory activity correlates positively with their ageing whilst in circulation. Aged neutrophils represent an overly active subset exhibiting enhanced αMβ2 integrin activation and neutrophil extracellular trap formation under inflammatory conditions. Neutrophil ageing is driven by the microbiota via Toll-like receptor and myeloid differentiation factor 88-mediated signalling pathways. Depletion of the microbiota significantly reduces the number of circulating aged neutrophils and dramatically improves the pathogenesis and inflammation-related organ damage in models of sickle-cell disease or endotoxin-induced septic shock. These results identify a role for the microbiota in regulating a disease-promoting neutrophil subset. PMID:26374999

  14. Neutrophils: game changers in glomerulonephritis?

    PubMed Central

    Mayadas, Tanya N.; Rosetti, Florencia; Ernandez, Thomas; Sethi, Sanjeev

    2010-01-01

    Glomerulonephritides represent a diverse array of diseases that have in common immune cell-mediated effector mechanisms that cause organ damage. The contribution of neutrophils to the pathogenesis of proliferative glomerulonephritis (GN) is not well recognized. Most equate neutrophils with killing pathogens and causing collateral tissue damage during acute inflammation. However, these phagocytes are endowed with additional characteristics that have been traditionally reserved for cells of the adaptive immune system. They communicate with other cells, exhibit plasticity in their responses and have the potential to coordinate and inform the subsequent immune response, thus countering the notion that they arrive, destroy and then disappear. Therefore, neutrophils, which are the first to arrive at a site of inflammation, are potential game changers in GN. PMID:20667782

  15. Ras regulates alveolar macrophage formation of CXC chemokines and neutrophil activation in streptococcal M1 protein-induced lung injury.

    PubMed

    Zhang, Songen; Hwaiz, Rundk; Rahman, Milladur; Herwald, Heiko; Thorlacius, Henrik

    2014-06-15

    Streptococcal toxic shock syndrome (STSS) is associated with a high mortality rate. The M1 serotype of Streptococcus pyogenes is most frequently associated with STSS. Herein, we examined the role of Ras signaling in M1 protein-induced lung injury. Male C57BL/6 mice received the Ras inhibitor (farnesylthiosalicylic acid, FTS) prior to M1 protein challenge. Bronchoalveolar fluid and lung tissue were harvested for quantification of neutrophil recruitment, edema and CXC chemokine formation. Neutrophil expression of Mac-1 was quantified by use of flow cytometry. Quantitative RT-PCR was used to determine gene expression of CXC chemokines in alveolar macrophages. Administration of FTS reduced M1 protein-induced neutrophil recruitment, edema formation and tissue damage in the lung. M1 protein challenge increased Mac-1 expression on neutrophils and CXC chemokine levels in the lung. Inhibition of Ras activity decreased M1 protein-induced expression of Mac-1 on neutrophils and secretion of CXC chemokines in the lung. Moreover, FTS abolished M1 protein-provoked gene expression of CXC chemokines in alveolar macrophages. Ras inhibition decreased chemokine-mediated neutrophil migration in vitro. Taken together, our novel findings indicate that Ras signaling is a potent regulator of CXC chemokine formation and neutrophil infiltration in the lung. Thus, inhibition of Ras activity might be a useful way to antagonize streptococcal M1 protein-triggered acute lung injury. PMID:24704370

  16. Neutrophil activation during acetaminophen hepatotoxicity and repair in mice and humans

    SciTech Connect

    Williams, C. David; Bajt, Mary Lynn; Sharpe, Matthew R.; McGill, Mitchell R.; Farhood, Anwar; Jaeschke, Hartmut

    2014-03-01

    Following acetaminophen (APAP) overdose there is an inflammatory response triggered by the release of cellular contents from necrotic hepatocytes into the systemic circulation which initiates the recruitment of neutrophils into the liver. It has been demonstrated that neutrophils do not contribute to APAP-induced liver injury, but their role and the role of NADPH oxidase in injury resolution are controversial. C57BL/6 mice were subjected to APAP overdose and neutrophil activation status was determined during liver injury and liver regeneration. Additionally, human APAP overdose patients (ALT: > 800 U/L) had serial blood draws during the injury and recovery phases for the determination of neutrophil activation. Neutrophils in the peripheral blood of mice showed an increasing activation status (CD11b expression and ROS priming) during and after the peak of injury but returned to baseline levels prior to complete injury resolution. Hepatic sequestered neutrophils showed an increased and sustained CD11b expression, but no ROS priming was observed. Confirming that NADPH oxidase is not critical to injury resolution, gp91{sup phox}−/− mice following APAP overdose displayed no alteration in injury resolution. Peripheral blood from APAP overdose patients also showed increased neutrophil activation status after the peak of liver injury and remained elevated until discharge from the hospital. In mice and humans, markers of activation, like ROS priming, were increased and sustained well after active liver injury had subsided. The similar findings between surviving patients and mice indicate that neutrophil activation may be a critical event for host defense or injury resolution following APAP overdose, but not a contributing factor to APAP-induced injury. - Highlights: • Neutrophil (PMN) function increases during liver repair after acetaminophen overdose. • Liver repair after acetaminophen (APAP)-overdose is not dependent on NADPH oxidase. • Human PMNs do not appear

  17. Neutrophil dynamics in the blood and milk of crossbred cows naturally infected with Staphylococcus aureus

    PubMed Central

    Swain, Dilip K.; Kushwah, Mohar Singh; Kaur, Mandheer; Dang, Ajay K.

    2015-01-01

    Aim: The present study was designed to evaluate the neutrophil dynamics in terms of the functional competence during subclinical mastitis (SCM) and clinical mastitis (CM). Materials and Methods: A total of 146 Karan fries cows were screened and were divided into three groups as control (n=12), SCM, n=12 and CM, n=12 groups on the basis of California mastitis test scoring, bacteriological evaluation, gross and morphological changes in milk and by counting milk somatic cell count (SCC). Both blood and milk polymorphonuclear neutrophils (PMNs) were isolated in the study. Phagocytic activity (PA) was studied by spectrophotometrically; neutrophil extracelluar traps (NETs) were studied by scanning electron microscopy (SEM); CD44 was quantified by flow cytometry and apoptosis was studied by fluorescent microscopy. Results: Significantly (p<0.05) higher SCC, PA was found in milk of CM cows as compared to SCM and control cows. Significantly lower (p<0.05) apoptosis was observed in PMNs isolated from both blood and milk of CM group of cows when compared to control and SCM group. The milk neutrophils of CM group of cows formed NETs as evidenced from the SEM images. Surface expression of CD44 revealed a significantly (p<0.05) lower expression in milk neutrophils of CM group of cows when compared to SCM and control group of cows. Conclusion: The study indicated a positive correlation between delayed neutrophil apoptosis, persistent staying of neutrophils at the site of infection along with formation of NETs as the strategies to fight against the pathogens in the udder during Staphylococcal mastitis. The study forms a strong base for future molecular research in terms of neutrophil recruitment and neutrophil removal from the site of infection. PMID:27047094

  18. APPLICATION OF PROTEOMICS TO NEUTROPHIL BIOLOGY

    PubMed Central

    Luerman, Gregory C.; Uriarte, Silvia M.; Rane, Madhavi J.; McLeish, Kenneth R.

    2009-01-01

    Polymorphonuclear leukocytes or neutrophils are a primary effector cell of the innate immune system and contribute to the development of adaptive immunity. Neutrophils participate in both the initiation and resolution of inflammatory responses through a series of highly coordinated molecular and phenotypic changes. To accomplish these changes, neutrophils express numerous receptors and use multiple overlapping and redundant signal transduction pathways. Dysregulation of the activation or resolution pathways plays a role in a number of human diseases. A comprehensive understanding of the regulation of neutrophil responses can be provided by high throughput proteomic technologies and sophisticated computational analysis. The first steps in the application of proteomics to understanding neutrophil biology have been taken. Here we review the application of expression, structural, and functional proteomic studies to neutrophils. Although defining the complex molecular events associated with neutrophil activation is in the early stages, the data generated to date suggest that proteomic technologies will dramatically enhance our understanding of neutrophil biology. PMID:19580889

  19. Role of neutrophils in systemic autoimmune diseases

    PubMed Central

    2013-01-01

    Neutrophils have emerged as important regulators of innate and adaptive immune responses. Recent evidence indicates that neutrophils display marked abnormalities in phenotype and function in various systemic autoimmune diseases, and may play a central role in initiation and perpetuation of aberrant immune responses and organ damage in these conditions. This review discusses the putative roles that neutrophils and aberrant neutrophil cell death play in the pathogenesis of various systemic autoimmune diseases, including systemic lupus erythematosus, small vessel vasculitis and rheumatoid arthritis. PMID:24286137

  20. Type I interferon transcriptional signature in neutrophils and high frequency of low-density granulocytes are associated with tissue damage in malaria

    PubMed Central

    Rocha, Bruno Coelho; Marques, Pedro Elias; Leoratti, Fabiana Maria de Souza; Junqueira, Caroline; Pereira, Dhelio Batista; Antonelli, Lis Ribeiro do Valle; Menezes, Gustavo Batista

    2015-01-01

    SUMMARY Neutrophils are the most abundant leukocyte population in the bloodstream, the primary compartment of Plasmodium sp. infection. Yet, the role of these polymorphonuclear cells in mediating either resistance or pathogenesis of malaria is poorly understood. We report that circulating neutrophils from malaria patients are highly activated, as indicated by a strong type I interferon transcriptional signature, increased expression of surface activation markers, the enhanced release of reactive oxygen species and myeloperoxidase, as well as the high frequency of low-density granulocytes. The activation of neutrophils was associated with increased levels of serum alanine and aspartate aminotransferases, indicating liver damage. In a rodent malaria model, we observed an intense recruitment of neutrophils to liver sinusoids. Neutrophil migration, IL-1β and chemokine expression as well as liver damage were all dependent on type I interferon signaling. The data suggests that type I interferon signaling have a central role in neutrophil activation and malaria pathogenesis. PMID:26711347

  1. Recruitment by Brainstorming.

    ERIC Educational Resources Information Center

    Hankin, Joseph N.

    1982-01-01

    Reports on Westchester Community College's (WCC's) campuswide brainstorming meetings which prepared strategies, programs, and recommendations for realizing recruitment goals. Includes a draft of WCC's 1981 Marketing Recruitment Plan, which covers programs and instruction, services, admissions office and processes, publications, and…

  2. BAFF-secreting neutrophils drive plasma cell responses during emergency granulopoiesis.

    PubMed

    Parsa, Roham; Lund, Harald; Georgoudaki, Anna-Maria; Zhang, Xing-Mei; Ortlieb Guerreiro-Cacais, André; Grommisch, David; Warnecke, Andreas; Croxford, Andrew L; Jagodic, Maja; Becher, Burkhard; Karlsson, Mikael C I; Harris, Robert A

    2016-07-25

    Prolonged infections or adjuvant usage can trigger emergency granulopoiesis (EG), leading to dysregulation in neutrophil blood counts. However, the impact of EG on T and B cell function remains largely unknown. In this study, to address this question, we used a mouse model of neutropenia and studied immune activation after adjuvant administration. The initial neutropenic state fostered an environment of increased dendritic cell activation and T cell-derived IL-17 production. Interestingly, neutropenic lysozyme 2-diphtheria toxin A mice exhibited striking EG and amplified neutrophil recruitment to the lymph nodes (LNs) that was dependent on IL-17-induced prostaglandin activity. The recruited neutrophils secreted a B cell-activating factor that highly accelerated plasma cell generation and antigen-specific antibody production. Reduction of neutrophil functions via granulocyte colony-stimulating factor neutralization significantly diminished plasma cell formation, directly linking EG with the humoral immune response. We conclude that neutrophils are capable of directly regulating T cell-dependent B cell responses in the LN. PMID:27432941

  3. Reverse-migrated neutrophils regulated by JAM-C are involved in acute pancreatitis-associated lung injury

    PubMed Central

    Wu, Deqing; Zeng, Yue; Fan, Yuting; Wu, Jianghong; Mulatibieke, Tunike; Ni, Jianbo; Yu, Ge; Wan, Rong; Wang, Xingpeng; Hu, Guoyong

    2016-01-01

    Junctional adhesion molecule-C (JAM-C) plays a key role in the promotion of the reverse transendothelial migration (rTEM) of neutrophils, which contributes to the dissemination of systemic inflammation and to secondary organ damage. During acute pancreatitis (AP), systemic inflammatory responses lead to distant organ damage and typically result in acute lung injury (ALI). Here, we investigated the role of rTEM neutrophils in AP-associated ALI and the molecular mechanisms by which JAM-C regulates neutrophil rTEM in this disorder. In this study, rTEM neutrophils were identified in the peripheral blood both in murine model of AP and human patients with AP, which elevated with increased severity of lung injury. Pancreatic JAM-C was downregulated during murine experimental pancreatitis, whose expression levels were inversely correlated with both increased neutrophil rTEM and severity of lung injury. Knockout of JAM-C resulted in more severe lung injury and systemic inflammation. Significantly greater numbers of rTEM neutrophils were present both in the circulation and pulmonary vascular washout in JAM-C knockout mice with AP. This study demonstrates that during AP, neutrophils that are recruited to the pancreas may migrate back into the circulation and then contribute to ALI. JAM-C downregulation may contribute to AP-associated ALI via promoting neutrophil rTEM. PMID:26841848

  4. Reverse-migrated neutrophils regulated by JAM-C are involved in acute pancreatitis-associated lung injury.

    PubMed

    Wu, Deqing; Zeng, Yue; Fan, Yuting; Wu, Jianghong; Mulatibieke, Tunike; Ni, Jianbo; Yu, Ge; Wan, Rong; Wang, Xingpeng; Hu, Guoyong

    2016-01-01

    Junctional adhesion molecule-C (JAM-C) plays a key role in the promotion of the reverse transendothelial migration (rTEM) of neutrophils, which contributes to the dissemination of systemic inflammation and to secondary organ damage. During acute pancreatitis (AP), systemic inflammatory responses lead to distant organ damage and typically result in acute lung injury (ALI). Here, we investigated the role of rTEM neutrophils in AP-associated ALI and the molecular mechanisms by which JAM-C regulates neutrophil rTEM in this disorder. In this study, rTEM neutrophils were identified in the peripheral blood both in murine model of AP and human patients with AP, which elevated with increased severity of lung injury. Pancreatic JAM-C was downregulated during murine experimental pancreatitis, whose expression levels were inversely correlated with both increased neutrophil rTEM and severity of lung injury. Knockout of JAM-C resulted in more severe lung injury and systemic inflammation. Significantly greater numbers of rTEM neutrophils were present both in the circulation and pulmonary vascular washout in JAM-C knockout mice with AP. This study demonstrates that during AP, neutrophils that are recruited to the pancreas may migrate back into the circulation and then contribute to ALI. JAM-C downregulation may contribute to AP-associated ALI via promoting neutrophil rTEM. PMID:26841848

  5. Microbe-specific unconventional T-cells induce human neutrophil differentiation into antigen cross-presenting cells

    PubMed Central

    Liuzzi, Anna Rita; Tyler, Christopher J.; Khan, Mohd Wajid A.; Szakmany, Tamas; Hall, Judith E.; Moser, Bernhard; Eberl, Matthias

    2014-01-01

    The early immune response to microbes is dominated by the recruitment of neutrophils whose primary function is to clear invading pathogens. However, there is emerging evidence that neutrophils play additional effector and regulatory roles. The present study demonstrates that human neutrophils assume antigen cross-presenting functions, and suggests a plausible scenario for the local generation of APC-like neutrophils through the mobilization of unconventional T-cells in response to microbial metabolites. Vγ9/Vδ2 T-cells and MAIT cells are abundant in blood, inflamed tissues and mucosal barriers. Here, both human cell types responded rapidly to neutrophils after phagocytosis of Gram-positive and Gram-negative bacteria producing the corresponding ligands, and in turn mediated the differentiation of neutrophils into APCs for both CD4+ and CD8+ T-cells through secretion of GM-CSF, IFN-γ and TNF-α. In patients with acute sepsis, circulating neutrophils displayed a similar APC-like phenotype and readily processed soluble proteins for cross-presentation of antigenic peptides to CD8+ T-cells, at a time when peripheral Vγ9/Vδ2 T-cells were highly activated. Our findings indicate that unconventional T-cells represent key controllers of neutrophil-driven innate and adaptive responses to a broad range of pathogens. PMID:25165152

  6. Type 2 Interleukin-4 Receptor Signaling in Neutrophils Antagonizes Their Expansion and Migration during Infection and Inflammation.

    PubMed

    Woytschak, Janine; Keller, Nadia; Krieg, Carsten; Impellizzieri, Daniela; Thompson, Robert W; Wynn, Thomas A; Zinkernagel, Annelies S; Boyman, Onur

    2016-07-19

    Neutrophils are the first immune cells recruited to sites of inflammation and infection. However, patients with allergic disorders such as atopic dermatitis show a paucity of skin neutrophils and are prone to bacterial skin infections, suggesting that allergic inflammation curtails neutrophil responses. Here we have shown that the type 2 cell signature cytokine interleukin-4 (IL-4) hampers neutrophil expansion and migration by antagonizing granulocyte colony-stimulating factor (G-CSF) and chemokine receptor-mediated signals. Cutaneous bacterial infection in mice was exacerbated by IL-4 signaling and improved with IL-4 inhibition, each outcome inversely correlating with neutrophil migration to skin. Likewise, systemic bacterial infection was worsened by heightened IL-4 activity, with IL-4 restricting G-CSF-induced neutrophil expansion and migration to tissues by affecting CXCR2-CXCR4 chemokine signaling in neutrophils. These effects were dependent on IL-4 acting through type 2 IL-4 receptors on neutrophils. Thus, targeting IL-4 might be beneficial in neutropenic conditions with increased susceptibility to bacterial infections. PMID:27438770

  7. Neutral serine proteases of neutrophils.

    PubMed

    Kettritz, Ralph

    2016-09-01

    Neutrophil serine proteases (NSPs) exercise tissue-degrading and microbial-killing effects. The spectrum of NSP-mediated functions grows continuously, not least because of methodological progress. Sensitive and specific FRET substrates were developed to study the proteolytic activity of each NSP member. Advanced biochemical methods are beginning to characterize common and specific NSP substrates. The resulting novel information indicates that NSPs contribute not only to genuine inflammatory neutrophil functions but also to autoimmunity, metabolic conditions, and cancer. Tight regulatory mechanisms control the proteolytic potential of NSPs. However, not all NSP functions depend on their enzymatic activity. Proteinase-3 (PR3) is somewhat unique among the NSPs for PR3 functions as an autoantigen. Patients with small-vessel vasculitis develop autoantibodies to PR3 that bind their target antigens on the neutrophil surface and trigger neutrophil activation. These activated cells subsequently contribute to vascular necrosis with life-threatening multiorgan failure. This article discusses various aspects of NSP biology and highlights translational aspects with strong clinical implications. PMID:27558338

  8. Neutrophil alveolitis in bronchioloalveolar carcinoma: induction by tumor-derived interleukin-8 and relation to clinical outcome.

    PubMed Central

    Bellocq, A.; Antoine, M.; Flahault, A.; Philippe, C.; Crestani, B.; Bernaudin, J. F.; Mayaud, C.; Milleron, B.; Baud, L.; Cadranel, J.

    1998-01-01

    Tumor infiltrate, predominantly constituted by lymphocytes, may represent an important prognostic factor in bronchioloalveolar carcinoma (BAC), in addition to tumor extension and histological type. In the present study, we determined the presence, the origin, and the prognostic importance of neutrophils that also participate in leukocyte infiltrates of BAC. Neutrophil alveolitis was determined immunohistochemically in both lung biopsies and bronchoalveolar lavage (BAL) fluid samples from 29 patients with histologically proved BAC. The local expression of interleukin (IL)-8 was determined by immunohistochemical and immunoenzymatic techniques. Neutrophil counts were analyzed in relation to the clinical outcome of patients by the Kaplan-Meier method and Cox's univariate and stepwise multivariate models. Lymphocytes and neutrophils dominated the inflammatory cell population in the lower respiratory tract of patients with BAC. Neutrophils were located mainly in the alveolar lumen and seldom in alveolar wall whereas lymphocytes were exclusively present in alveolar wall. A relationship was observed between the number of neutrophils and the level of IL-8 in BAL fluid suggesting the involvement of that chemokine in neutrophil recruitment. The tumor cells were the predominant cells that appeared to express IL-8 by immunolocalization. The presence of increased numbers of neutrophils was significantly associated with a poorer outcome in patients with BAC (P = 0.02). In a multivariate analysis, the neutrophil percentage in BAL fluid was an independent predictor of clinical outcome. The risk of death was increased substantially (rate ratio, 5.2; 95% confidence interval, 1.1 to 24.7) among patients with BAL neutrophil percentage of > or = 39% (median of the distribution) as compared with the others. In BAC, neutrophils accumulate in the alveolar lumen. Elaboration of IL-8 by tumor cells may be responsible for this event, which is associated with a significantly higher risk of

  9. Recruitment and Training. Symposium.

    ERIC Educational Resources Information Center

    2002

    This document contains three papers from a symposium on recruitment and training. "College Choice: The State of Marketing and Effective Student Recruitment Strategies" (Fredrick Muyia Nafukho, Michael F. Burnett) reports on a study of the recruitment strategies used by Louisiana State University's admissions office and College of Agriculture that…

  10. Endothelial LSP1 Modulates Extravascular Neutrophil Chemotaxis by Regulating Nonhematopoietic Vascular PECAM-1 Expression.

    PubMed

    Hossain, Mokarram; Qadri, Syed M; Xu, Najia; Su, Yang; Cayabyab, Francisco S; Heit, Bryan; Liu, Lixin

    2015-09-01

    During inflammation, leukocyte-endothelial cell interactions generate molecular signals that regulate cell functions. The Ca(2+)- and F-actin-binding leukocyte-specific protein 1 (LSP1) expressed in leukocytes and nonhematopoietic endothelial cells is pivotal in regulating microvascular permeability and leukocyte recruitment. However, cell-specific function of LSP1 during leukocyte recruitment remains elusive. Using intravital microscopy of cremasteric microvasculature of chimeric LSP1-deficient mice, we show that not neutrophil but endothelial LSP1 regulates neutrophil transendothelial migration and extravascular directionality without affecting the speed of neutrophil migration in tissue in response to CXCL2 chemokine gradient. The expression of PECAM-1-sensitive α6β1 integrins on the surface of transmigrated neutrophils was blunted in mice deficient in endothelial LSP1. Functional blocking studies in vivo and in vitro elucidated that α6β1 integrins orchestrated extravascular directionality but not the speed of neutrophil migration. In LSP1-deficient mice, PECAM-1 expression was reduced in endothelial cells, but not in neutrophils. Similarly, LSP1-targeted small interfering RNA silencing in murine endothelial cells mitigated mRNA and protein expression of PECAM-1, but not ICAM-1 or VCAM-1. Overexpression of LSP1 in endothelial cells upregulated PECAM-1 expression. Furthermore, the expression of transcription factor GATA-2 that regulates endothelial PECAM-1 expression was blunted in LSP1-deficient or LSP1-silenced endothelial cells. The present study unravels endothelial LSP1 as a novel cell-specific regulator of integrin α6β1-dependent neutrophil extravascular chemotactic function in vivo, effective through GATA-2-dependent transcriptional regulation of endothelial PECAM-1 expression. PMID:26238489